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Literature on Biodiesel NOx Emissions

This page lists articles published worldwide in journal, book, magazine or otherwise about Biodiesel NOx emissions. Please provide us a feedback feedback if you see any error in this listing or you would like to report and articles that should have been in this section. Your help will make this a great place to find articles about biodiesel feedstock.

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  1. Antioxidant (A-tocopherol acetate) effect on oxidation stability and NOx emission reduction in methyl ester of Annona oil operated diesel engine
    Abstract

    Senthil, R.; Silambarasan, R.; Pranesh, G. 2017. Antioxidant (A-tocopherol acetate) effect on oxidation stability and NOx emission reduction in methyl ester of Annona oil operated diesel engine. Heat and Mass Transfer. 53(5) 1797-1804

    There is a major drawback while using biodiesel as a alternate fuel for compression ignition diesel engine due to lower heating value, higher viscosity, higher density and higher oxides of nitrogen emission. To minimize these drawbacks, fuel additives can contribute towards engine performance and exhaust emission reduction either directly or indirectly. In this current work, the test was conducted to investigate the effect of antioxidant additive (A-tocopherol acetate) on oxidation stability and NOx emission in a of Annona methyl ester oil (MEAO) fueled diesel engine. The A-tocopherol acetate is mixed in different concentrations such as 0.01, 0.02, 0.03 and 0.04% with 100% by vol MEAO. It is concluded that the antioxidant additive very effective in increasing the oxidation stability and in controlling the NOx emission. Further, the addition of antioxidant additive is slight increase the HC, CO and smoke emissions. Hence, A-tocopherol acetate is very effective in controlling the NOx emission with MEAO operated diesel engine without any major modification.
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  2. Biodiesel unsaturation degree effects on diesel engine NOx emissions and cotton wick flame temperature
    Abstract

    Abdullah, M. F. E.; Zhing, S. S.; Bugik, C. B. 2017. Biodiesel unsaturation degree effects on diesel engine NOx emissions and cotton wick flame temperature. 2nd International Conference on Automotive Innovation and Green Vehicle (Aigev 2016). 90

    As compared with conventional diesel fuel, biodiesel has better lubricity and lower particulate matter (PM) emissions however nitrogen oxides (NOx) emissions generally increase in biodiesel-fuelled diesel engine. Strict regulation on NOx emissions is being implemented in current Euro 6 standard and it is expected to be tighter in next standard, thus increase of NOx cannot be accepted. In this study, biodiesel unsaturation degree effects on NOx emissions are investigated. Canola, palm and coconut oils are selected as the feedstock based on their unsaturation degree. Biodiesel blends of B20 were used to fuel a single cylinder diesel engine and exhaust emissions were sampled directly at exhaust tailpipe with a flue gas analyser. Biodiesel flame temperature was measured from a cotton wick burned in simple atmospheric conditions using a thermocouple. Fourier transform infrared (FTIR) spectrometer was also used to identify the functional groups presence in the biodiesel blends. Oxygen content in biodiesel may promote complete combustion as the NOx emissions and flame temperatures were increased while the carbon monoxide (CO) emissions were decreased for all biodiesel blends. It is interesting to note that the NOx emissions and flame temperatures were directly proportional with biodiesel unsaturation degree. It might be suggested that apart from excess oxygen and free radical formation, higher NOx emissions can also be caused by the elevated flame temperatures due to the presence of double bonds in unsaturated biodiesel.
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  3. Combustion characteristics and NOx emissions of a waste cooking oil biodiesel blend in a marine auxiliary diesel engine
    Abstract

    Geng, P.; Mao, H. J.; Zhang, Y. J.; Wei, L. J.; You, K.; Ju, J.; Chen, T. K. 2017. Combustion characteristics and NOx emissions of a waste cooking oil biodiesel blend in a marine auxiliary diesel engine. Applied Thermal Engineering. 115947-954

    The International Maritime Organization (IMO) has enacted the Maritime Agreement Regarding Oil Pollution (MARPOL) VI to regulate the ship emissions. In the large ocean-going ship, the marine auxiliary diesel engine is widely used to produce electricity, and it could also generate large amounts of harmful emissions. In order to reduce these emissions, some alternative fuels were used in the marine diesel engine. In term of this, the combustion and emissions characteristics and emissions of a 6-cyclinder turbo-charged inter-cooling direct-injection marine auxiliary diesel engine was investigated in this study when using Ultralow Sulfur Diesel (ULSD), B70 (diesel containing 70 vol.% of biodiesel), B90 and neat waste cooking oil biodiesel (6100), respectively. The influence of high biodiesel to diesel ratio on the combustion characteristics and NOx (NO and NO2) emissions was studied, under 25%, 50%, 75% engine load at 1050 r/min and 1500 r/min (Rated speed) conditions. The experimental results indicated that the cylinder pressure decreases slightly with increasing the biodiesel content in the test fuels, while the ignition advances, ignition delay reduces and combustion duration becomes longer. When the test engine operated at low load, the maximum percent peak heat release rate (HRR) decreases is about 14.3%, while the maximum percent can reach to 21.3% at high load condition. For each test fuel, the cylinder pressure and peak heat release rate increase significantly with the increase of engine load. The temperature of the exhaust manifold decreases with the increases of biodiesel content in the test fuels. Moreover, the NOx emissions decrease significantly when using the high substitution ratio of biodiesel, which is due to the decrease of the cylinder temperature in the diffusion combustion mode. The NO emission increases with the increases of the engine torque, while the NO2 emission decreases. Consequently, the ratio of NO2 to NO decreases sharply with the increases of engine load, due to the increase of the cylinder temperature. (C) 2017 Elsevier Ltd. All rights reserved.
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  4. Comparative study of NOx emissions of biodiesel-diesel blends from soybean, palm and waste frying oils using methyl and ethyl transesterification routes
    Abstract

    da Silva, M. A. V.; Ferreira, B. L. G.; Marques, L. G. D.; Murta, A. L. S.; de Freitas, M. A. V. D. 2017. Comparative study of NOx emissions of biodiesel-diesel blends from soybean, palm and waste frying oils using methyl and ethyl transesterification routes. Fuel. 194144-156

    The research for renewable and less polluting fuels has focused on biodiesel. This fuel can derive from vegetable, animal or waste oils, and despite its potential to decrease atmospheric pollutants and greenhouse gases, its influence on NOx emissions is still uncertain. It is believed that biodiesel emissions, especially NOx vary depending on the feedstock, blend percentage and transesterification route. A better understanding of these factors can help choosing the best blend. In this context, this article aims at evaluating how the variation of these factors affects NOx emissions. Tests are carried out in a stationary internal combustion engine with 20% and 50% blends of methyl and ethyl esters made from soybean oil, palm oil and waste frying oil (collected in the University Campus). The analysis of the results with Tukey's test compare their means and lead to the conclusion that, when considering the route, ethyl blends have lower NOx emissions, and palm ethyl ester blends had the best results. Also when all factors are taken into account, B20 from soybean methyl ester has the lowest emissions of NOx. We recommend that future studies test the effect of antioxidants in NOx emissions, as well as test higher blend ratios. (C) 2016 Elsevier Ltd. All rights reserved.
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  5. Effects of biodiesel made from swine and chicken fat residues on carbon monoxide, carbon dioxide, and nitrogen oxide emissions
    Abstract

    Feddern, V.; Cunha Junior, A.; De Pra, M. C.; Busi da Silva, M. L.; Nicoloso, R. D. S.; Higarashi, M. M.; Coldebella, A.; de Abreu, P. G. 2017. Effects of biodiesel made from swine and chicken fat residues on carbon monoxide, carbon dioxide, and nitrogen oxide emissions. J Air Waste Manag Assoc. 67(7) 754-762

    The effects of two alternative sources of animal fat-derived biodiesel feedstock on CO2, CO, NOx tailpipe emissions as well as fuel consumption were investigated. Biodiesel blends were produced from chicken and swine fat waste (FW-1) or floating fat (FW-2) collected from slaughterhouse wastewater treatment processes. Tests were conducted in an unmodified stationary diesel engine operating under idling conditions in attempt to simulate slow traffic in urban areas. Significant reductions in CO (up to 47% for B100; FW-2) and NOx (up to 20% for B5; FW-2 or B100; FW-1) were attained when using biodiesel fuels at the expense of 5% increase in fuel consumption. Principal component analysis (PCA) was performed to elucidate possible associations among gas (CO2, CO, and NOx) emissions, cetane number and iodine index with different sources of feedstock typically employed in the biodiesel industry. NOx, cetane number and iodine index were inversely proportional to CO2 and biodiesel concentration. High NOx emissions were reported from high iodine index biodiesel derived especially from forestry, fishery and some agriculture feedstocks, while the biodiesel derived from animal sources consistently presented lower iodine index mitigating NOx emissions. The obtained results point out the applicability of biodiesel fuels derived from fat-rich residues originated from animal production on mitigation of greenhouse gas emissions. The information may encourage practitioners from biodiesel industry whilst contributing towards development of sustainable animal production. IMPLICATIONS: Emissions from motor vehicles can contribute considerably to the levels of greenhouse gases in the atmosphere. The use of biodiesel to replace or augment diesel can not only decrease our dependency on fossil fuels but also help decrease air pollution. Thus, different sources of feedstocks are constantly being explored for affordable biodiesel production. However, the amount of carbon monoxide (CO), carbon dioxide (CO2), and/or nitrogen oxide (NOx) emissions can vary largely depending on type of feedstock used to produce biodiesel. In this work, the authors demonstrated animal fat feasibility in replacing petrodiesel with less impact regarding greenhouse gas emissions than other sources.
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  6. Influence of polymethyl acrylate additive on the formation of particulate matter and NOX emission of a biodiesel-diesel-fueled engine
    Abstract

    Monirul, I. M.; Masjuki, H. H.; Kalam, M. A.; Zulkifli, N. W. M.; Shancita, I. 2017. Influence of polymethyl acrylate additive on the formation of particulate matter and NOX emission of a biodiesel-diesel-fueled engine. Environ Sci Pollut Res Int.

    The aim of this study is to investigate the effect of the polymethyl acrylate (PMA) additive on the formation of particulate matter (PM) and nitrogen oxide (NOX) emission from a diesel coconut and/or Calophyllum inophyllum biodiesel-fueled engine. The physicochemical properties of 20% of coconut and/or C. inophyllum biodiesel-diesel blend (B20), 0.03 wt% of PMA with B20 (B20P), and diesel fuel were measured and compared to ASTM D6751, D7467, and EN 14214 standard. The test results showed that the addition of PMA additive with B20 significantly improves the cold-flow properties such as pour point (PP), cloud point (CP), and cold filter plugging point (CFPP). The addition of PMA additives reduced the engine's brake-specific energy consumption of all tested fuels. Engine emission results showed that the additive-added fuel reduce PM concentration than B20 and diesel, whereas the PM size and NOX emission both increased than B20 fuel and baseline diesel fuel. Also, the effect of adding PMA into B20 reduced Carbon (C), Aluminum (Al), Potassium (K), and volatile materials in the soot, whereas it increased Oxygen (O), Fluorine (F), Zinc (Zn), Barium (Ba), Chlorine (Cl), Sodium (Na), and fixed carbon. The scanning electron microscope (SEM) results for B20P showed the lower agglomeration than B20 and diesel fuel. Therefore, B20P fuel can be used as an alternative to diesel fuel in diesel engines to lower the harmful emissions without compromising the fuel quality.
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  7. Prediction of NOx emissions from a simplified biodiesel surrogate by applying stochastic simulation algorithms (SSA)
    Abstract

    Omidvarborna, H.; Kumar, A.; Kim, D. S. 2017. Prediction of NOx emissions from a simplified biodiesel surrogate by applying stochastic simulation algorithms (SSA). Combustion Theory and Modelling. 21(2) 346-357

    A stochastic simulation algorithm (SSA) approach is implemented with the components of a simplified biodiesel surrogate to predict NOx (NO and NO2) emission concentrations from the combustion of biodiesel. The main reaction pathways were obtained by simplifying the previously derived skeletal mechanisms, including saturated methyl decenoate (MD), unsaturated methyl 5-decanoate (MD5D), and n-decane (ND). ND was added to match the energy content and the C/H/O ratio of actual biodiesel fuel. The MD/MD5D/ND surrogate model was also equipped with H-2/CO/C-1 formation mechanisms and a simplified NOx formation mechanism. The predicted model results are in good agreement with a limited number of experimental data at low-temperature combustion (LTC) conditions for three different biodiesel fuels consisting of various ratios of unsaturated and saturated methyl esters. The root mean square errors (RMSEs) of predicted values are 0.0020, 0.0018, and 0.0025 for soybean methyl ester (SME), waste cooking oil (WCO), and tallow oil (TO), respectively. The SSA model showed the potential to predict NOx emission concentrations, when the peak combustion temperature increased through the addition of ultra-low sulphur diesel (ULSD) to biodiesel. The SSA method used in this study demonstrates the possibility of reducing the computational complexity in biodiesel emissions modelling.
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  8. A comprehensive study on the improvement of oxidation stability and NOx emission levels by antioxidant addition to biodiesel blends in a light-duty diesel engine
    Abstract

    Rashed, M. M.; Masjuki, H. H.; Kalam, M. A.; Alabdulkarem, A.; Imdadul, H. K.; Rashedul, H. K.; Shahin, M. M.; Habibullah, M. 2016. A comprehensive study on the improvement of oxidation stability and NOx emission levels by antioxidant addition to biodiesel blends in a light-duty diesel engine. Rsc Advances. 6(27) 22436-22446

    Moringa oleifera oil, a non-edible biodiesel feedstock with high unsaturated fatty acid content, was used in this study. MB20 (20% Moringa oil methyl ester and 80% diesel fuel blend) was mixed with three antioxidants, namely, N, N'-diphenyl-1,4-phenylenediamine (DPPD), N-phenyl-1,4-phenylenediamine (NPPD) and 2-ethylhexyl nitrate (EHN), at a concentration of 1000 ppm. The effects of these antioxidants on the oxidation stability of biodiesel as well as on the exhaust emission and performance of a singlecylinder diesel engine were analysed. After the Rancimat test, oxidation stability was enhanced by the antioxidants in the order of DPPD > NPPD > EHN. Results also showed that DPPD-, NPPD-and EHN-treated blends reduced NOx emissions within 5.9-8.80% compared with those in the untreated blend because of suppressed free radical formation. Antioxidant-treated blends contained high amounts of carbon monoxide and hydrocarbon and showed improved smoke opacity, thereby indicating that emissions were below the diesel fuel emission levels. Results demonstrated that antioxidant addition to MB20 improves engine performance characteristics. This study shows that MB20 blends with antioxidants can be used in diesel engines without any modification.
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  9. A laboratory investigation on the effects of unsaturated bonds and chain lengths of different biodiesel feedstocks on carbon dioxide, carbon monoxide, and methane emissions under low-temperature combustion
    Abstract

    Omidvarborna, H.; Kumar, A.; Kim, D. S. 2016. A laboratory investigation on the effects of unsaturated bonds and chain lengths of different biodiesel feedstocks on carbon dioxide, carbon monoxide, and methane emissions under low-temperature combustion. Journal of Environmental Chemical Engineering. 4(4) 4769-4775

    Biodiesel fuel is produced from various types of feedstock and as a result, its chemical composition and exhaust emissions may vary depending on the feedstock type. In this study, combustion of three biodiesel fuels derived from soybean methyl ester (SME), waste cooking oil (WCO), and tallow oil (TO) was carried out separately in a combustion chamber to better understand the effects of feedstock type on carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) emissions under low-temperature combustion (LTC) and fuel-rich conditions. Additionally, blended biodiesel fuels, B20 and B50, with ultra-low sulfur diesel (ULSD) of these biodiesel fuels were examined. From the impact of different biodiesel feedstocks on combustion parameters, linear relationships were observed between the fuels and the peak combustion temperature and pressure (R-2 values ranging from 0.82 to 0.98). ULSD showed the highest emission of CO and the lowest emissions of CO2 and CH4 among the other fuels. Compared to ULSD, it was found that the use of pure biodiesel fuels reduced the CO and enhanced CO2 emissions by a factor of 1/3 and 3, respectively. Biodiesel fuel with a high degree of unsaturation and high portion of long methyl esters such as SME appeared to produce more CO and less CO2 emissions than those with low degrees of unsaturation and short chain lengths (WCO and TO). It is thought that the length of fatty acid methyl esters (FAMEs) affects the emissions because shorter chains, which contain less unsaturated structures, have the high oxygen-to-carbon ratio. (C) 2016 Elsevier Ltd. All rights reserved.
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  10. A review of the effect of the composition of biodiesel on NOx emission, oxidative stability and cold flow properties
    Abstract

    Lanjekar, R. D.; Deshmukh, D. 2016. A review of the effect of the composition of biodiesel on NOx emission, oxidative stability and cold flow properties. Renewable & Sustainable Energy Reviews. 541401-1411

    This paper will review and attempt to discover the ideal fatty acid composition of biodiesel which exhibits lower NOx emissions, better oxidative stability and cold flow properties. The physicochemical properties of biodiesel strongly depend on their fatty acid composition. A high percentage of unsaturated fatty acid in biodiesel is correlated with higher NOx emissions, poor oxidative stability and better cold flow properties. The presence of saturated fatty acids (SFA), in particular the long chain type, exhibits good oxidative stability and produces lower NOx emissions. SFA do however demonstrate poor cold flow properties. The polyunsaturated fatty acids (PUFA) exhibit better cold flow properties but produces higher NOx emissions and poorer oxidative stability.
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  11. Application of low-level biodiesel blends on heavy-duty (diesel) engines: Feedstock implications on NOx and particulate emissions
    Abstract

    Karavalakis, G.; Johnson, K. C.; Hajbabaei, M.; Durbin, T. D. 2016. Application of low-level biodiesel blends on heavy-duty (diesel) engines: Feedstock implications on NOx and particulate emissions. Fuel. 181259-268

    The use of low levels of biodiesel in diesel fuel is becoming more widespread throughout the world, and yet there is still limited information on the actual impact of low concentration biodiesel blends on NOx emissions. For this purpose, two different methyl ester feedstocks produced from soybean oil and animal tallow were tested at B5 and B10 levels in a 2006 Cummins ISM engine and a 1991 DDC Series 60 engine over the Federal Test Procedure (FTP), the Urban Dynamometer Driving Schedule (UDDS), and the Supplementary Emission Test (SET) cycles. Increases in nitrogen oxide (NOx) emissions were found for the unsaturated soy B5/B10 blends for the 2006 Cummins engine over the FTP and UDDS cycles and for the 1991 DDC engine over different combinations of all three cycles. Unlike the unsaturated soy blends, the higher saturated animal fat-based biodiesel did not show consistent NOx increases, with only the B10-animal blend showing a statistical significant increase for the FTP on the 1991 DDC engine. The differences in NOx emissions between the biodiesel feedstocks were likely due to differences in the degree of unsaturation in the ester. The low level biodiesel blends also showed reductions in particulate matter (PM), total hydrocarbon (THC), and carbon monoxide (CO) emissions, consistent with the trends seen for higher biodiesel blend levels. (C) 2016 Elsevier Ltd. All rights reserved.
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  12. Artificial neural network prediction of NOx emissions from EGR and non-EGR engines running on soybean biodiesel fuel (B5) during cold idle mode
    Abstract

    Omidvarborna, H.; Kumar, A.; Kim, D. S. 2016. Artificial neural network prediction of NOx emissions from EGR and non-EGR engines running on soybean biodiesel fuel (B5) during cold idle mode. Environmental Progress & Sustainable Energy. 35(5) 1537-1544

    Artificial neural network (ANN) prediction scheme was developed for nitrogen oxides (NOx) emissions in cold idle mode based on the analysis of NOx emissions from on-road transit buses operating on a blend of biodiesel. The input data necessary for training and testing the proposed ANN scheme was obtained from two different urban transit buses fueled with 5 vol% soybean methyl ester (SME) and 95% of ultra-low sulfur diesel (ULSD). One bus was equipped with exhaust gas recirculation (EGR) and the other one was not. The reduction of NOx emissions was observed when EGR was implemented. A standard feed forward back-propagation algorithm was used in this analysis and in building the network structure, whereas Levenberge-Marquardt (LM) learning algorithm was used to predict the NOx emissions. The study was carried out with 70% of total experimental data selected for training the neural network, 15% for the network's validation, and the remaining 15% data were used for testing the performance of the trained network. ANN results showed that the developed ANN model was capable of predicting the NOx emissions of the tested engines with excellent agreement (correlation coefficients: 0.99
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  13. Experimental Analysis and Modeling of NOx Emissions in Compression Ignition Engines Fueled with Blends of Diesel and Palm Oil Biodiesel
    Abstract

    Quiceno, A. P. V.; Quintero, R. F. C.; Merola, S. S.; Irimescu, A.; Valentino, G. 2016. Experimental Analysis and Modeling of NOx Emissions in Compression Ignition Engines Fueled with Blends of Diesel and Palm Oil Biodiesel. Vehits: Proceedings of the International Conference on Vehicle Technology and Intelligent Transport Systems. 245-252

    In this work, theoretical and experimental studies about the effects of the blends of diesel and palm oil biodiesel on NOx formation in compression-ignition engines were developed. Experiments were conducted using commercial diesel, palm oil biodiesel and blends at 5% (B5), 20% (B20) and 50% (B50) as fuels. A phenomenological semi-empirical model that uses the information obtained from thermodynamic diagnostics was used for determining the theoretical NOx formation. The model shows the high sensitivity of NOx formation to the temperature and the operating conditions. Effects associated to the operating conditions of the engine were evaluated and the results indicate that high engine loads and low speeds lead to the NOx formation. However, it was not possible to determine with precision, the effect of the type of fuel, because of the high sensitivity of the NOx formation with respect to the operating conditions of the engine.
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  14. EXPERIMENTAL STUDY ON COMBUSTION AND NOx EMISSION CHARACTERISTICS OF ACIDIC OIL BIODIESEL
    Abstract

    Ma, Z. H.; Li, Z. B.; Zhu, Y. D.; Sun, J. 2016. EXPERIMENTAL STUDY ON COMBUSTION AND NOx EMISSION CHARACTERISTICS OF ACIDIC OIL BIODIESEL. Energy and Mechanical Engineering. 775-785

    The combustion and NOx (Nitrogen Oxide) emission characteristics experiment fueled with conventional diesel fuel and four different fuel blends of acidic oil biodiesel (B5, B10, B15 and B20) were conducted in a four-cylinder, electronic controlled high-pressure common-rail, turbocharged diesel engine without any structure modifications. The results showed that operations with acidic oil biodiesel blends had increase in ignition delay, maximum in-cylinder pressure, heat release rate peak in diffusion combustion duration, cumulative heat release and maximum in-cylinder temperature compared with baseline diesel. In addition, the heat release rate peak and in-cylinder pressure rise rate peak in premixed combustion duration of biodiesel blends were decreased and their crank angular positions were lagged obviously. The NOx emission of biodiesel blends increased, especially at high loads.
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  15. Factors influencing NOx emission of a stationary diesel engine fuelled with crude rice bran oil methyl ester blend - Taguchi approach
    Abstract

    Saravanan, S.; Nagarajan, G.; Rao, G. L. N. 2016. Factors influencing NOx emission of a stationary diesel engine fuelled with crude rice bran oil methyl ester blend - Taguchi approach. International Journal of Sustainable Engineering. 9(3) 182-188

    The main objective of this work is to control the NOx emission of a stationary diesel engine fuelled with crude rice bran oil methyl ester blend with less sacrifice on smoke density and brake thermal efficiency (BTE) and also to investigate the factors influencing the objective. Fuel injection timing, percentage of exhaust gas recirculation and fuel injection pressure are chosen as the promising factors for the objective and NOx emission, smoke density and BTE are considered as response variables. Tests were conducted as per Taguchi's L-9 orthogonal array and the most influencing factor for each response variable and also the significance of each factor on the same was found out through analysis of variance (ANOVA). Response graph was drawn for each response variable and from the results of response graph and ANOVA the optimum combination of the factor levels in achieving the objective was obtained and the same was confirmed experimentally.
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  16. Impact of antioxidants on NOx emissions from a mango seed biodiesel powered DI diesel engine
    Abstract

    Velmurugan, K.; Sathiyagnanam, A. P. 2016. Impact of antioxidants on NOx emissions from a mango seed biodiesel powered DI diesel engine. Alexandria Engineering Journal. 55(1) 715-722

    The uses of biodiesel in diesel engines result in reduction of exhaust emissions, though many researchers described that the biodiesel produces higher NOx emissions than diesel, which is detract from the inflation of the market for these fuels. The aim of the present study was to analyze the experimental exploration of the three antioxidants DEA (Di-Ethyl Amine), PHC (Pyridoxine Hydro Chloride) and TBHQ (Tert Butyl Hydro Quinone) on engine emission and performance of a single cylinder diesel engine fueled with methyl ester of mango seed. The experiment is conducted with different antioxidant concentrations of mango seed methyl ester mixtures (100, 250, 500 and 1000 ppm). The results exhibited that PHC is effectual in controlling NOx emissions than TBHQ and DEA. (C) 2015 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V.
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  17. IMPACT OF UREA DIRECT INJECTION ON NOx EMISSION FORMATION OF DIESEL ENGINES FUELED BY BIODIESEL
    Abstract

    Yang, W. M.; An, H.; Li, J.; Zhou, D. Z.; Kraft, M. 2016. IMPACT OF UREA DIRECT INJECTION ON NOx EMISSION FORMATION OF DIESEL ENGINES FUELED BY BIODIESEL. Proceedings of the Asme Internal Combustion Engine Division Fall Technical Conference, 2015, Vol 2.

    There are many NO, removal technologies: exhaust gas recirculation (EGR), selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), miller cycle, emulsion technology and engine performance optimization. In this work, a numerical simulation investigation was conducted to explore the possibility of an alternative approach: direct aqueous urea solution injection on the reduction of NO, emissions of a biodiesel fueled diesel engine. Simulation was performed using the 3D CFD simulation software KIVA4 coupled with CHEMKIN II code for pure biodiesel combustion under realistic engine operating conditions of 2400 rpm and 100% load. To improve the overall prediction accuracy, the Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) spray break up model was implemented in the KIVA code to replace the original Taylor Analogy Breakup (TAB) model for the primary and secondary fuel breakup processes modeling. The KIVA4 code was further modified to accommodate multiple injections, different fuel types and different injection orientations. A skeletal reaction mechanism for biodiesel + urea was developed which consists of 95 species and 498 elementary reactions. The chemical behaviors of the NOx formation and Urea/NOx interaction processes were modeled by a modified extended Zeldovich mechanism and Urea/NOx interaction sub mechanism. Developed mechanism was first validated against the experimental results conducted on a light duty 2KD FTV Toyota car engine fueled by pure biodiesel in terms of in cylinder pressure, heat release rate. To ensure an efficient NO, reduction process, various aqueous urea injection strategies in terms of post injection timing and injection rate were carefully examined. The simulation results revealed that among all the four post injection timings (10 degrees ATDC, 15 degrees ATDC, 20 degrees ATDC and 25 degrees ATDC) that were evaluated, 15 degrees ATDC post injection timing consistently demonstrated a lower NO emission level. In addition, both the urea/water ratio and aqueous urea injection rate demonstrated important roles which affected the thermal decomposition of urea into ammonia and the subsequent NO, removal process, and it was suggested that 50% urea mass fraction and 40% injection rate presented the lowest NO, emission levels.
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  18. Influence of fuel (diesel and biodiesel) features and fleet vehicles transport group of NOx emissions in Curitiba, Parana, Brazil
    Abstract

    Ribas, W. F.; Bilotta, P.; Janissek, P. R.; Carvalho, M. A. D.; Neto, R. A. P. 2016. Influence of fuel (diesel and biodiesel) features and fleet vehicles transport group of NOx emissions in Curitiba, Parana, Brazil. Engenharia Sanitaria E Ambiental. 21(3) 437-445

    The public transportation system in Curitiba, Parana, Brazil, is recognized by its innovative solutions; and is a model for Brazil. In this work, the influence of fuel (diesel and biodiesel) and the conditions of the public transport vehicle fleet of Curitiba in NOx emissions was assessed, and this is a pioneered initiative. A total of 188 vehicles (9.7% of the total) with engines of 7 and 12 L were selected, named B7R, B10M, B12M and B215RH, and measurements of NO and NO2 were performed in the exhaust output. In relation to the type of fuel, the emissions of NO and NO2 for biodiesel (B100) were, respectively, 37 and 26% superior to the values observed with the fuel diesel (S10). Comparing the engines B12M with up to 3 and 10 years of operation, the average emissions of NOx were close to 40% higher. Thus, it was possible to observe that the biodiesel vehicles had higher NOx emissions when compared with diesel vehicles in similar conditions of operation and engine wear time. Therefore, although the use of biodiesel brings environmental advantages, as renewable fuel, new technologies and devices must be developed to control emissions of NO and NO2 in engines that use this type of fuel. For future works the authors recommend tests on dynamometer to simulate NOx emission in diesel and biodiesel engine in different conditions of charge and engine speed.
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  19. Influence of Residence Time on Fuel Spray Sauter Mean Diameter (Smd) and Emissions Using Biodiesel and Its Blends in a Low Nox Gas Turbine Combustor
    Abstract

    Altaher, M. A.; Li, H.; Andrews, G. E. 2016. Influence of Residence Time on Fuel Spray Sauter Mean Diameter (Smd) and Emissions Using Biodiesel and Its Blends in a Low Nox Gas Turbine Combustor. Proceedings of the Asme Turbo Expo: Turbine Technical Conference and Exposition, 2016, Vol 3.

    Biodiesels have advantages of low carbon footprint, reduced toxic emissions, improved energy supply security and sustainability and therefore attracted attentions in both industrial and aero gas turbines sectors. Industrial gas turbine applications are more practical biodiesels due to low temperature waxing and flow problems at altitude for aero gas turbine applications. This paper investigated the use of biodiesels in a low NOx radial swirler, as used in some industrial low NOx gas turbines. A waste cooking oil derived methyl ester biodiesel (WME) was tested on a radial swirler industrial low NOx gas turbine combustor under atmospheric pressure, 600K air inlet temperature and reference Mach number of 0.017&0.023. The pure WME, its blends with kerosene (B20 and B50) and pure kerosene were tested for gaseous emissions and lean extinction as a function of equivalence ratio for both Mach numbers. Sauter Mean Diameter (SMD) of the fuel spray droplets was calculated. The results showed that the WME and its blends had lower CO, UHC emissions and higher NOx emissions than the kerosene. The weak extinction limits were determined for all fuels and B100 has the lowest value. The higher air velocity (at Mach=0.023) resulted in smaller SMDs which improved the mixing and atomizing of fuels and thus led to reductions in NOx emissions.
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  20. NOx emissions from low-temperature combustion of biodiesel made of various feedstocks and blends
    Abstract

    Omidvarborna, H.; Kumar, A.; Kim, D. S. 2015. NOx emissions from low-temperature combustion of biodiesel made of various feedstocks and blends. Fuel Processing Technology. 140113-118

    Nitrogen oxides (NOx) are one of the major hazardous emissions from biodiesel-fueled engines that need to be regulated stringently. In this paper, NOx emissions from different types of biodiesel were studied using a laboratory combustion chamber. Biodiesel fuels with various portion of fatty acid methyl esters (FAMEs) from soybean methyl ester (SME), tallow oil (TO), and waste cooking oil (WCO) were combusted at 330-420 degrees C simulating low-temperature combustion (LTC). Combustion analysis results show that neat biodiesel fuels had longer ignition delay and lower ignition temperatures compared to ultra-low sulfur diesel (ULSD). The unsaturation of biodiesel samples and their blends with ULSD was analyzed for its effects on NOx emissions. The results showed that biodiesel with more unsaturated fatty acids emitted more NOx compared to biodiesel with more saturated fatty acids. A paired t-test showed that neat TO, WCO, and WCO B50 had significant reduction in the formation of NOx compared with ULSD and SME B20. It is concluded that less unsaturated FAME fuels would be preferable when reduction of NOx emissions is a critical issue. (C) 2015 Elsevier B.V. All rights reserved.
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  21. Simultaneous Reduction of NOx and HC Emissions in a CI Engine Fueled with Methyl Ester of Neem Oil Using Ethylenediamine as Antioxidant Additive
    Abstract

    Balaji, G.; Cheralathan, M. 2015. Simultaneous Reduction of NOx and HC Emissions in a CI Engine Fueled with Methyl Ester of Neem Oil Using Ethylenediamine as Antioxidant Additive. Energy Sources Part a-Recovery Utilization and Environmental Effects. 37(24) 2684-2691

    Biodiesel offers cleaner combustion over conventional diesel fuel, including reduced particulate matter, carbon monoxide, and unburned hydrocarbon emissions. However, several studies point to an increase in NOx emissions for biodiesel fuel compared with conventional diesel fuel. In this article, the experimental investigation of the effect of antioxidant additive (ethylenediamine) on NOx and HC emissions in a methyl ester of neem oil fueled direct-injection diesel engine has been reported. The antioxidant additive is mixed in various proportions with methyl ester of neem oil and was tested in a computerized four-stroke water-cooled single-cylinder diesel engine of 3.5 kW rated power. Results show that the antioxidant additive is effective in controlling the NOx and HC emissions of methyl ester of neem oil fueled diesel engines.
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  22. A STUDY ON BIODIESEL NOx EMISSION CONTROL WITH THE REDUCED CHEMICAL KINETICS MODEL
    Abstract

    Li, J. C.; Lee, C. F. F.; Han, Z. Y.; Shen, C.; Wang, M. Z. 2014. A STUDY ON BIODIESEL NOx EMISSION CONTROL WITH THE REDUCED CHEMICAL KINETICS MODEL. Proceedings of the Asme Internal Combustion Engine Division Fall Technical Conference, 2013, Vol 2.

    In this paper, the effects of the start of injection (SOI) timing and EGR rate on the nitrogen oxide (NO.) emissions of biodiesel-powered diesel engine are studied with computational fluid dynamics (CFD) coupling with a chemical kinetics model. A surrogate biodiesel mechanism consisting of two fuel components is employed as the combustion model of soybean biodiesel. The in-cylinder combustion processes of the cases with four injection timings and three exhaust gas recirculation (EGR) rates are simulated. The simulation results show that the NO emissions of biodiesel combustion can be effectively improved by SOT retardation or increasing EGR rate. The calculated NO emissions of the cases with default EGR rate are reduced by 20.3% and 32.9% when the injection timings are delayed by 2-degree and 4-degree crank angle, respectively. The calculated NO emissions of the cases with 24.0% and 28.0% EGR are reduced by 38.4% and 62.8%, respectively, compared to that of the case with default SOT and 19.2% EGR. But higher EGR rate deteriorates the soot emission. When EGR rate is 28.0% and SOT is advanced by 2-degree, the NO emission is reduced by 55.1% and soot emission is controlled as that of the case with 24% EGR and default SOI.
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  23. A Study on Biodiesel NOx Emission Control With the Reduced Chemical Kinetics Model
    Abstract

    Li, J. C.; Han, Z. Y.; Shen, C.; Lee, C. F. 2014. A Study on Biodiesel NOx Emission Control With the Reduced Chemical Kinetics Model. Journal of Engineering for Gas Turbines and Power-Transactions of the Asme. 136(10)

    In this paper, the effects of the start of injection (SOI) timing and exhaust gas recirculation (EGR) rate on the nitrogen oxides (NOx) emissions of a biodiesel-powered diesel engine are studied with computational fluid dynamics (CFD) coupling with a chemical kinetics model. The KIVA code coupling with a CHEMKIN-II chemistry solver is applied to the simulation of the in-cylinder combustion process. A surrogate biodiesel mechanism consisting of two fuel components is employed as the combustion model of soybean biodiesel. The in-cylinder combustion processes of the cases with four injection timings and three EGR rates are simulated. The simulation results show that the calculated NOx emissions of the cases with default EGR rate are reduced by 20.3% and 32.9% when the injection timings are delayed by 2- and 4- deg crank angle, respectively. The calculated NOx emissions of the cases with 24.0% and 28.0% EGR are reduced by 38.4% and 62.8%, respectively, compared to that of the case with default SOI and 19.2% EGR. But higher EGR rate deteriorates the soot emission. When EGR rate is 28.0% and SOI is advanced by 2 deg, the NOx emission is reduced by 55.1% and soot emission is controlled as that of the case with 24% EGR and default SOI. The NOx emissions of biodiesel combustion can be effectively improved by SOI retardation or increasing EGR rate. Under the studied engine operating conditions, introducing more 4.8% EGR into the intake air with unchanged SOI is more effective for NOx emission controlling than that of 4-deg SOI retardation with default EGR rate.
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  24. Assessment of NOx Emissions during Transient Diesel Engine Operation with Biodiesel Blends
    Abstract

    Giakoumis, E. G.; Rakopoulos, C. D.; Rakopoulos, D. C. 2014. Assessment of NOx Emissions during Transient Diesel Engine Operation with Biodiesel Blends. Journal of Energy Engineering. 140(3)

    The target of the present work is to review the literature regarding the effects of biodiesel blends on nitrogen oxide (NOx) emissions during the transient operation of diesel engines (acceleration, load increase, starting, driving cycles). The most important mechanisms are analyzed on the basis of the fundamental aspects of transient conditions and the effects that biodiesel physical and chemical properties have relative to conventional diesel oil; biodiesel feedstock and driving cycle effects are also emphasized. In parallel, a comprehensive statistical analysis is presented regarding the effects of biodiesel blends on NOx emissions for engines running on transient cycles during the last 30 years. For the majority of the reviewed transients, an increasing trend in NOx emissions is established when the biodiesel ratio in the fuel blend increases. Moreover, the biodiesel NOx emission penalty seems to increase for more aggressive cycles and for increasing feedstock unsaturation. (C) 2014 American Society of Civil Engineers.
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  25. Attempts to Reduce Biodiesel Blends Nox Pollutant Emissions by Ultrasonic Conditioning
    Abstract

    Mariasiu, F. 2014. Attempts to Reduce Biodiesel Blends Nox Pollutant Emissions by Ultrasonic Conditioning. Transport. 29(1) 43-49

    The conditions imposed by the renewable energy Directive 2009/28/EC make it mandatory for EU member countries to ensure that by 2020 fossil fuels used in the transport sector contain a 10% component of biofuel. The 10% limit is based on results of experiments conducted by engine manufacturers and researchers in the biofuels domain, which show that this percentage can be used in IC engines without major technical changes to equipment and engine systems. Taking into account that increasing the percentage of biodiesel in blends results in significant reductions of CO2 emissions, an immediate way to surpass the 10% limit is to carry out external and/or internal processes that will act on the physico-chemical properties of those biofuels. This paper presents data and results from experiments examining the process of ultrasonic irradiation of rapeseed oil methyl ester type biodiesel. The results show the effects of the irradiation process on biodiesel physical parameters such as density, kinematic viscosity, speed of sound through the medium, and isentropic bulk modulus. The values of these parameters directly influence the operation, performance and pollutant emissions of diesel engines. Primary results obtained demonstrate the possibilities of using what we call here the B25 blend with low-cost procedures and without major technical intervention in the equipment used to construct diesel engines. Two parameters important for the injection process (kinematic viscosity and density) show equal values for B25Us_irr ultrasonically irradiated for 350 seconds and diesel fuel ultrasonically irradiated for 420 seconds. The range of the achieved NOx pollutant emission reduction was between 18.2% for the ultrasonically irradiated blend B25Us_irr (no load) and 1.4% for the ultrasonically irradiated blend B100Us_irr (100% load), when compared with untreated basic biodiesel.
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  26. Experimental investigation of the effect of antioxidant additives on NOx emissions of a diesel engine using biodiesel
    Abstract

    Ileri, E.; Kocar, G. 2014. Experimental investigation of the effect of antioxidant additives on NOx emissions of a diesel engine using biodiesel. Fuel. 12544-49

    In this study, the effect of the antioxidant additives on the oxidation stability of biodiesel and the exhaust emissions of a diesel engine has been studied. Biodiesel used in this study was produced via transesterification process from canola oil, and was blended with diesel fuel 20% by volume (B20). Antioxidant additives butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butylhydroquinone (TBHQ) and 2-ethylhexyl nitrate (EHN) were individually dissolved at concentrations of 0, 500, 750 and 1000 ppm by weight in B20 fuel blend for experiments. The test results of oxidation stability showed that the effectiveness of the antioxidants was in the order of TBHQ > BHA > BHT > EHN. According to exhaust emissions test results, antioxidant additives had quite effects on oxides of nitrogen (NOx), carbon monoxide (CO) and hydrocarbon (HC) emissions of diesel engine running on biodiesel. A 1000 ppm concentration of EHN additive was optimal as NOx levels were substantially reduced in the whole engine speed in comparison with B20 fuel. (C) 2014 Elsevier Ltd. All rights reserved.
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  27. Experimental reduction of NOx and HC emissions in a CI engine fuelled with methyl ester of neem oil using p-phenylenediamine antioxidant
    Abstract

    Balaji, G.; Cheralathan, M. 2014. Experimental reduction of NOx and HC emissions in a CI engine fuelled with methyl ester of neem oil using p-phenylenediamine antioxidant. Journal of Scientific & Industrial Research. 73(3) 177-180

    Biodiesel, a renewable substitute to conventional diesel and offers cleaner combustion including reduced particulate matter, carbon monoxide and unburned hydrocarbon emissions. However, several studies point to increase in NO emissions for biodiesel fuel compared with conventional diesel fuel. In this paper, the experimental investigation of the effect of antioxidant additive (p-phenylenediamine) on NOx and HC emissions in a methyl ester of neem oil fuelled direct injection diesel engine has been reported. The antioxidant additive is mixed in various concentrations (0.010 to 0.040 % (w/w)) with methyl ester of neem oil and was tested in computerized 4-stroke water-cooled single cylinder diesel engine of 3.5 kW rated power. Results show that the antioxidant additive is effective in controlling the NO and HC emissions of methyl ester of neem oil fuelled diesel engines.
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  28. Impact of nozzle holes configuration on fuel spray, wall impingement and NOx emission of a diesel engine for biodiesel-diesel blend (B20)
    Abstract

    Lahane, S.; Subramanian, K. A. 2014. Impact of nozzle holes configuration on fuel spray, wall impingement and NOx emission of a diesel engine for biodiesel-diesel blend (B20). Applied Thermal Engineering. 64(1-2) 307-314

    A diesel engine fueled with biodiesel-diesel blend (B20) decreases CO, HC and smoke emissions drastically. However, NOx emission and chance of wall impingement increased significantly leading to the problems of the diesel engine for use of the biodiesel-diesel blend. Hence, the study is aimed at reduction in NOx emission of the engine at source level and chance of wall impingement using the modified nozzle configuration (5 (base) and 6 (modified) holes). NOx emission of the engine for B20 fuel decreased from 7.4 g/kW-hr with the base nozzle configuration to 6.6 g/kW-hr with modified nozzle configuration due to reduction in in-cylinder temperature, retarding in dynamic injection timing, reduction in spray penetration distance. The spray penetration distance for B20 with the modified nozzle configuration is lesser resulting in less chance of wall impingement resulting in solution to the main durable issues of diesel engines for B20. The spray characteristics including sauter mean diameter, penetration distance and air entrainment are analyzed for B20 fuel in detail. The NOx emission is well correlated with spray penetration distance. The modification of nozzle configuration (number of holes) is a solution to reduce NOx emission of biodiesel fueled diesel engine at source level and also the chance of wall impingement with tangible benefits of HC, CO, smoke and BSEC reduction. (C) 2013 Elsevier Ltd. All rights reserved.
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  29. Impacts of NOx reducing antioxidant additive on performance and emissions of a multi-cylinder diesel engine fueled with Jatropha biodiesel blends
    Abstract

    Palash, S. M.; Kalam, M. A.; Masjuki, H. H.; Arbab, M. I.; Masum, B. M.; Sanjid, A. 2014. Impacts of NOx reducing antioxidant additive on performance and emissions of a multi-cylinder diesel engine fueled with Jatropha biodiesel blends. Energy Conversion and Management. 77577-585

    Energy requirements are increasing rapidly due to fast industrialization and the increased number of vehicles on the road. The use of biodiesel in diesel engines instead of diesel results in the proven reduction of harmful exhaust emissions. However, most researchers have reported that they produce higher NOx emissions compared to diesel, which is a deterrent to the expansion of the market for these fuels. Several proposed pathways try to account for NOx formation during the combustion process. Among them, the Fenimore mechanism explains that fuel radicals formed during the combustion process react with nitrogen from the air to form NOx. It could be proposed that if these radical reactions could be terminated, the NOx formation rate for biodiesel combustion would decrease. An experimental study was conducted on a four-cylinder diesel engine to evaluate the performance and emission characteristics of Jatropha biodiesel blends (JB5, JB10, JB15 and JB20) with and without the addition of N,N'-diphenyl-1,4-phenylenediamine (DPPD) antioxidant. For each tested fuel, the engine performance and emissions were measured at engine speeds 1000-4000 rpm at an interval of 500 rpm under the full throttle condition. The results showed that this antioxidant additive could reduce NOx emissions significantly with a slight penalty in terms of engine power and Brake Specific Fuel Consumption (BSFC) as well as CO and HC emissions. However, when compared to diesel combustion, the emissions of HC and CO with the addition of the DPPD additive were found to be nearly the same or lower. By the addition of 0.15% (m) DPPD additive in JB5, JB10, JB15 and JB20, the reduction in NOx emissions were 8.03%, 3.503%, 13.65% and 16.54% respectively, compared to biodiesel blends without the additive under the full throttle condition. Moreover, the addition of DPPD additive to all biodiesel blend samples reduced the exhaust gas temperature. (C) 2013 Elsevier Ltd. All rights reserved.
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  30. Theoretical and experimental investigation on effect of injection timing on NOx emission of biodiesel blend
    Abstract

    Saravanan, S.; Nagarajan, G.; Rao, G. L. N.; Sampath, S. 2014. Theoretical and experimental investigation on effect of injection timing on NOx emission of biodiesel blend. Energy. 66216-221

    The present work explores the possibility of simultaneous reduction of NOx and smoke of a stationary CI (compression ignition) engine fuelled with biodiesel blend. Fuel injection timing is retarded which resulted in lower NOx emission with an increased smoke intensity. NOx emission of the biodiesel at the standard and retarded injection timing was predicted with the help of developed correlations and the same was compared with the NOx emission experimentally determined. It was observed that the predicted NOx emission of biodiesel is comparable with the experimentally determined. Fuel injection pressure was increased at the retarded injection timing and its effect on NOx and smoke emission was investigated. It was observed that the increase in smoke intensity resulting from the retarded injection timing was reduced significantly by increasing the fuel injection pressure. (C) 2014 Elsevier Ltd. All rights reserved.
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  31. Effect of aromatic amine antioxidants on NOx emissions from a soybean biodiesel powered DI diesel engine
    Abstract

    Varatharajan, K.; Cheralathan, M. 2013. Effect of aromatic amine antioxidants on NOx emissions from a soybean biodiesel powered DI diesel engine. Fuel Processing Technology. 106526-532

    It is an overwhelming argument that the use of biodiesel instead of petrodiesel causes a reduction in harmful exhaust emissions from engines. A number of studies, however, indicate substantial increases in engine out NOx emissions with biodiesel fuel. Some studies have pointed out that the increased formation of prompt NOx is responsible for biodiesel NOx effect. Treatment of biodiesel with antioxidants is a promising approach because it reduces the formation of hydrocarbon free radicals, which are responsible for prompt NOx production in combustion process. Aromatic amine antioxidants are known as to be efficient inhibitors of free radicals. This study examines the use of p-phenylenediamine derived aromatic amine antioxidants for NOx reduction in a soybean biodiesel fuelled DI diesel engine. The antioxidant additives, N,N'-diphenyl-1,4-phenylenediamine (DPPD) and N-phenyl-1,4-phenylenediamine (NPPD) were tested on a computerised Kirloskar-make 4 stroke water cooled single cylinder diesel engine of 4.4 kW rated power. Results show that significant reduction of NOx could be achieved by the addition of antioxidants but smoke, CO and HC emissions were found to have increased. (C) 2012 Elsevier B.V. All rights reserved.
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  32. HC, CO, CO2 and NOx Emission evaluation of a diesel engine fueled with waste frying oil methyl ester
    Abstract

    Shirneshan, A. 2013. HC, CO, CO2 and NOx Emission evaluation of a diesel engine fueled with waste frying oil methyl ester. Second International Conference on Leadership, Technology and Innovation Management (2012). 75292-297

    In this paper, experiments were conducted on a 4-cylinder direct-injection diesel engine using biodiesel as an alternative fuel and their blends to investigate the emission characteristics of the engine under four engine loads at an engine speed of 1800 rev/min. A test was applied in which an engine was fueled with diesel and four different blends of diesel/biodiesel (B20, B40, B60 and B80) made from waste frying oil and the results were analyzed. The use of biodiesel resulted in lower emissions of hydrocarbon (HC) and CO and increased emissions of CO2 and NOx. This study showed that the exhaust emissions of diesel/biodiesel blends were lower than those of the diesel fuels.
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  33. Impacts of biodiesel combustion on NOx emissions and their reduction approaches
    Abstract

    Palash, S. M.; Kalam, M. A.; Masjuki, H. H.; Masum, B. M.; Fattah, I. M. R.; Mofijur, M. 2013. Impacts of biodiesel combustion on NOx emissions and their reduction approaches. Renewable & Sustainable Energy Reviews. 23473-490

    Increasing energy demand and environment concerns have prompted an evolution of alternative fuel sources. As an alternative fuel source, biodiesel is attractive because it reduces engine emissions. However, biodiesel produces higher NOx emissions compared to ordinary diesel fuel. Previous researches have established many factors that cause biodiesel to produce elevated NOx emissions. This study reviews the impacts of biodiesel combustion on NOx emissions and their reduction approaches in diesel engines. The first part of this study recaps the NOx formation mechanisms for understanding the kinetics behind the NOx forming reactions. The second part describes the factors affecting on NOx emissions. This paper established that higher NOx emissions are produced for biodiesel combustion which influenced by several factors such as physicochemical properties and molecular structure of biodiesel, adiabatic flame temperature, ignition delay time, injection timing and engine load conditions etc. The final section discusses on the reduction of NOx emissions from biodiesel fuelled engines for both pre and post combustion techniques. The results of reduction approaches of the NOx emissions implies, exhaust gas recirculation (EGR) and retarded injection timing are effective as well as low cost techniques than others. Between these two techniques, EGR reduces the NOx emissions at 5-25% EGR rate adequately in biofuelled engine by controlling oxygen content and combustion peak temperature with slightly decreasing HC and CO emissions. However this technique shows few penalties on smoke and PM emissions as well as brake specific fuel consumption if not perfectly optimized. (C) 2013 Elsevier Ltd. All rights reserved.
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  34. Impacts of N, N '-diphenyl-1, 4-phenylenediamine (DPPD) antioxidant additive in Jatropha biodiesel blends to reduce NOx emission of a multi cylinder vehicle type diesel engine
    Abstract

    Palash, S. M.; Kalam, M. A.; Masjuki, H. H.; Masum, B. M. 2013. Impacts of N, N '-diphenyl-1, 4-phenylenediamine (DPPD) antioxidant additive in Jatropha biodiesel blends to reduce NOx emission of a multi cylinder vehicle type diesel engine. Advanced Technologies in Manufacturing, Engineering and Materials, Pts 1-3. 774-776784-790

    To meet stringent exhaust emission norms worldwide, various exhaust pre-treatment and post-treatment techniques have been employed in modern engines. Using antioxidant additives in biodiesel fuels is a promising and effective NOx reduction technology. Non-edible jatropha oil based methyl ester was produced and blended with conventional diesel. Five fuel samples (Diesel, JB5, JB5DPPD0.15%, JB15 and JB15DPPD0.15%) were tested for their use as substitute fuel for a radiator-cooled four cylinder diesel engine. Experiment results show that DPPD antioxidant additive could be reduced NOx emission significantly with slight penalty on engine performance as well as CO and HC emission. However, when compared to diesel combustion the emissions of HC and CO were found nearly same or below. By addition of 0.15% (m) DPPD additive in JB5 and JB15 reduction of NOx emission were 12.68% and 13.36 % compared to biodiesel blends without additive at full throttle position. As conclusion, JB5 and JB15 with addition of 0.15% (m) can be used in four cylinder diesel engine to reduce NOx and consequently overcome the barrier to market expansion of biodiesel fuels.
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  35. NOx and particulate matter emissions from a diesel engine burning Jatropha biodiesel-ULSD fuel blends
    Abstract

    Nuhn, J.; Peltier, E.; Depcik, C.; Mangus, M.; Stagg-Williams, S. M. 2013. NOx and particulate matter emissions from a diesel engine burning Jatropha biodiesel-ULSD fuel blends. Abstracts of Papers of the American Chemical Society. 245

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  36. NOx Emission Control in a Bio-Diesel engine: Pre and Post-Combustion techniques using engine valve timing (EVT) and Electrical discharge plasma (EDP) Investigation and Analysis of NOx emission control of biodiesel engine using combined engine valve timing control and Pulse Discharge Plasma (PDP) based exhaust control techniques
    Abstract

    Srinivasan, A. D.; Rajagopala, R.; Jagadisha, N.; Chandrashekara, K. 2013. NOx Emission Control in a Bio-Diesel engine: Pre and Post-Combustion techniques using engine valve timing (EVT) and Electrical discharge plasma (EDP) Investigation and Analysis of NOx emission control of biodiesel engine using combined engine valve timing control and Pulse Discharge Plasma (PDP) based exhaust control techniques. 2013 Ieee Industry Applications Society Annual Meeting.

    A detailed investigation on NOx emission control from a stationary bio-diesel engine is carried out using combined engine valve timing control and pulse discharge plasma based exhaust control techniques. The objective of the study is to explore the effect of the valve timing (injection pressure, injection duration and injection quantity) on the NOX formation for various blends of Biodiesel samples and subsequently to treat the exhaust by the pulse discharge plasma based techniques. A comparative study of pre and post combustion technique on NOx removal will be discussed. Further, the experiments are carried out at different engine loading and exhaust flow rate. The effectiveness of the techniques with regard to NOx control and byproduct reduction is discussed.
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  37. Optimization of FOME (fish oil methyl esters) blend and EGR (exhaust gas recirculation) for simultaneous control of NOx and particulate matter emissions in diesel engines
    Abstract

    Bhaskar, K.; Nagarajan, G.; Sampath, S. 2013. Optimization of FOME (fish oil methyl esters) blend and EGR (exhaust gas recirculation) for simultaneous control of NOx and particulate matter emissions in diesel engines. Energy. 62224-234

    There is world-wide interest in the search for alternatives to petroleum derived fuels for diesel engines. Key driving factors are depleting fossil-fuel reserves all over the globe as well as the environmental impact of burning fossil fuels that cause pollution and global warming. Bio-diesel derived from edible oils, non-edible oils and animal fats can be used in diesel engines with little or no modification. Non-land-based renewable sources are becoming important for the production of biodiesel due to limited availability of land. Under these circumstances, fish oil extracted from wastes of processed marine fish and refined through transesterification becomes an attractive alternative for the production of biodiesel. In this work, performance and emission characteristics of FUME (fish oil methyl ester) and its blends are evaluated in a direct-injection single-cylinder constant-speed diesel engine primarily used in the agricultural sector. It is seen that 20% FOME blend gives almost the same brake thermal efficiency with lower unburned hydrocarbons, carbon monoxide and soot emissions but higher NOx (nitrogen oxides) emissions compared to diesel fuel. EGR (Exhaust Gas Recirculation) is used to control NOx emissions. Percentage of EGR is varied to determine optimum EGR for 20% FUME blend. (C) 2013 Elsevier Ltd. All rights reserved.
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  38. Performance and NOx emissions of a diesel engine fueled with biodiesel-diesel-water nanoemulsions
    Abstract

    Koc, A. B.; Abdullah, M. 2013. Performance and NOx emissions of a diesel engine fueled with biodiesel-diesel-water nanoemulsions. Fuel Processing Technology. 10970-77

    The purpose of this research was to investigate the effects of water concentration in a biodiesel nanoemulsion fuel on engine performance and exhaust emissions of a 4-cylinder diesel engine. Biodiesel nanoemulsions containing 5%, 10% and 15% water were used for the engine tests and the results were compared with B5, B20 and certified #2 diesel fuels. Biodiesel nanoemulsions produced lower NOx emissions and soot opacity than B5, B20 and certified #2 diesel fuels. Biodiesel nanoemulsion with 5% water concentration produced engine power and torque values that were similar to the values measured for B5 fuel. Increasing water concentrations in biodiesel nanoemulsions increased the engine brake specific fuel consumption and CO emissions. The rate of NOx reduction was greater than the rate of CO increase when the water concentration in biodiesel nanoemulsions increased from 10% to 15%. These results provided strong evidences on the effects of increasing water concentration in biodiesel emulsions on reducing NOx and soot from a 4-cylinder diesel engine. Emulsified biodiesel fuel is a promising alternative method for reducing harmful emissions from diesel engines without requiring significant engine modifications. (c) 2012 Elsevier B.V. All rights reserved.
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  39. Premixed Burn Fraction: Its Relation to the Variation in NOx Emissions between Petro- and Biodiesel
    Abstract

    Peirce, D. M.; Alozie, N. S. I.; Hatherill, D. W.; Ganippa, L. C. 2013. Premixed Burn Fraction: Its Relation to the Variation in NOx Emissions between Petro- and Biodiesel. Energy & Fuels. 27(7) 3838-3852

    It is commonly reported in the literature that NOx emissions from a diesel engine increase when fuelling with biodiesel. However, some studies report varying or opposite results. This work scrutinized operating conditions known to yield both increases and decreases in NOx emissions when running on biodiesel. This involved sweeping the injection timing of an instrumented 2 L diesel engine from 14 BTDC (before top-dead-center) to 3 ATDC (after top-dead-center), under loads of 40 Nm and 80 Nm (equating to BMEP (brake mean effective pressure) of 2.5 bar and 5 bar, respectively), using ultralow sulfur diesel (ULSD) and rapeseed methyl ester (RME). Under a 40 Nm load, RME consistently generated lower NOx emissions than ULSD, whereas, under an 80 Nm load, RME generated higher NOx emissions at all but the most advanced/retarded injection timings. This behavior was linked to differences in combustion duration, ignition delay (ID), and the relative size of the premixed burn fraction (PMBF). Combustion tended to progress more quickly overall for the fuel that generated highest NOx emissions at most operating conditions. ID was always reduced when fuelling with RME, and hence PMBF was also reduced. Thus, reduced ID exerted conflicting influences over relative RME NOx emissions; a tendency to increase NOx, due to advanced start of combustion (SOC), and a tendency to decrease NOx, due to reduced PMBF. Additionally, calculations indicated that for the same SOC and PMBF RME would normally be expected to generate higher NOx emissions than UISD. However, as the level of premixing increased, the magnitude of the ceteris paribus RME NOx increase appeared to dedine. That is, as PMBF increases, the impact of the inherent factors-beyond advanced SOC- that lead to higher NOx emissions when fuelling with biodiesel appear to be reduced. This may be related to variations in soot radiative heat losses. Changes in operating PMBF may therefore explain some of the variety that exists in the literature relating to the effects of biodiesel fuelling on NOx emissions.
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  40. Real-Time Study of Noxious Gas Emissions and Combustion Efficiency of Blended Mixtures of Neem Biodiesel and Petrodiesel
    Abstract

    Pillay, A.; Molki, A.; Elkadi, M.; Manuel, J.; Bojanampati, S.; Khan, M.; Stephen, S. 2013. Real-Time Study of Noxious Gas Emissions and Combustion Efficiency of Blended Mixtures of Neem Biodiesel and Petrodiesel. Sustainability. 5(5) 2098-2107

    Neem biodiesel is currently being explored as a future biofuel and was extracted chemically from the vegetable oil. Many of its properties are still under investigation and our aim was to study its noxious-gas emission profiles from blends with regular petroleum diesel. The distinct advantage of a real-time study is acquisition of in situ data on the combustion behavior of gas components with actual progression of time. Mixtures of neem biodiesel and petroleum diesel corresponding to neem additives of 5%, 10%, 15% and 25% were tested for combustion efficiency and emitted gases using a high-performance gas analyzer. Our study, therefore, investigated the overall efficiency of the combustion process linked to emissions of the following gases: O-2, CO2, NO, NOx and SO2. The results for the 95/5% blend compared to the neat sample were most promising and showed no serious change in performance efficiency (<2%). NO/NOx emission trends displayed maxima/minima, suggestive of interconvertible chemical reactivity. Declining CO and SO2 emissions were consistent with rapid chemical conversion. The CO and SO2 concentrations fell well below the toxic atmospheric limits in less than 300 s. The results are generally encouraging for blends below 10%. The potential environmental impact of the study is discussed.
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  41. Reduction of NOx emission on NiCrAl-Titanium Oxide coated direct injection diesel engine fuelled with radish (Raphanus sativus) biodiesel
    Abstract

    Ravikumar, V.; Senthilkumar, D. 2013. Reduction of NOx emission on NiCrAl-Titanium Oxide coated direct injection diesel engine fuelled with radish (Raphanus sativus) biodiesel. Journal of Renewable and Sustainable Energy. 5(6)

    The main aim of this study is the experimental investigation of single cylinder DI diesel engine with and without coating. Diesel and radish (Raphanus sativus) oil Methyl Ester are used as fuels and the results are compared to find the effect of biodiesel in a thermal barrier coating engine. For this purpose, engine cylinder head, valves, and piston crown are coated with 100 mu m of nickel-chrome-aluminium bond coat and 450 mu m of TiO2 by the plasma spray method. Radish oil methyl ester is produced by the transesterification process method. From the experimental investigation, slight increase in specific fuel consumption in thermal barrier coating engine is observed when compared with the uncoated engine, whereas NOx, HC, Smoke, and CO emissions decreased with coated engine for all test fuels used in the coated engine when compared with that of the uncoated engine. (C) 2013 AIP Publishing LLC.
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  42. State of the art of NOx mitigation technologies and their effect on the performance and emission characteristics of biodiesel-fueled Compression Ignition engines
    Abstract

    Palash, S. M.; Masjuki, H. H.; Kalam, M. A.; Masum, B. M.; Sanjid, A.; Abedin, M. J. 2013. State of the art of NOx mitigation technologies and their effect on the performance and emission characteristics of biodiesel-fueled Compression Ignition engines. Energy Conversion and Management. 76400-420

    Biodiesel fuels have the potential to become a reliable substitute for diesel which is used moderately to meet the current energy demands. This fuel can be produced from new or used vegetable oils, non-edible sources and animal fats, which are non-toxic, biodegradable and renewable. In spite of the many advantages of using biodiesel, most of the researchers have reported that they produce higher NOx emissions compared to diesel, which is a deterrent to the market expansion of these fuels. In this study, the different paths to reduce NOx emissions from diesel engines by applying several technologies, such as using additives into fuel, exhaust gas recirculation (EGR), water injection (WI), emulsion technology (ET), injection timing retardation (ITR), simultaneous technology (ST) and low temperature combustion (LTC) mode are reviewed briefly. The impacts of different NOx mitigation technologies on biodiesel-fueled diesel engine performance and emissions are also analyzed critically and different methods of their implementation are shown. This paper also provides a comparison of different NOx mitigation technologies based on previous articles related to this topic. From this comparative study, it was found that the average reduction of NOx emissions by using additives, EGR, WI 82 ET, ITR, ST and LTC are in the ranges 4-45%, 26-84%, 1038%, 9.77-37%, 22-95% and 66-93% respectively, compared to biodiesel combustion without applying technologies. However, the average reduction of NOx emissions by using those technologies for biodiesel are reasonable, 36-46%, 3-34%, 21-37%, 33-92% and 8.68-70% respectively, when compared to diesel. The results of this paper show that using new NOx mitigation technology, such as LTC, is more efficient and promising than the others because of its having the capability to reduce both NOx and particulate matter (PM) emissions simultaneously without significant penalties with regard to engine performance. However, applying this technology has increased CO and HC emissions in several cases due to the reduction in their oxidation rates in the combustion chamber. (C) 2013 Elsevier Ltd. All rights reserved.
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  43. An investigation of the impact of injection strategy and biodiesel on engine NOx and particulate matter emissions with a common-rail turbocharged DI diesel engine
    Abstract

    Ye, P.; Boehman, A. L. 2012. An investigation of the impact of injection strategy and biodiesel on engine NOx and particulate matter emissions with a common-rail turbocharged DI diesel engine. Fuel. 97476-488

    An investigation of the impact of engine injection strategy on NOx and particulate matter (PM) emissions with biodiesel fueling was conducted with a common-rail turbocharged direct injection diesel engine at moderate speed and different load/torque conditions. The fuels included a baseline ultra low sulfur diesel fuel (ULSD) and a B40 (v/v) blend of a soybean methyl ester (SME)-based biodiesel and ULSD. Single fuel injections at start of injection timings over a range from 9 degrees before to 3 degrees after top dead center with different fuel injection pressures were investigated. It is found that at all load conditions, an increase of fuel injection pressure significantly increases NOx emissions, and that with the same injection strategy as the baseline diesel, biodiesel fueling increases NOx emissions. For particulate matter emissions, it is found that an increase of fuel injection pressure decreases PM emissions for all load conditions. Meanwhile, biodiesel fueling has a more significant effect on PM emissions at low load and a less significant effect at moderate to high load. For an engine running with early SOI (highest brake fuel conversion efficiency in this work), a decrease of fuel injection pressure can counter the biodiesel NOx effect while maintaining a similar or even lower level of PM emissions as ULSD. Both biodiesel fueling and the change of fuel injection pressure did not significantly affect the brake fuel conversion efficiency, but retarding the start of injection appears to decrease it. Apparent heat release analysis shows a faster and higher heat release peak with higher fuel injection pressure. With biodiesel fueling, an earlier of start of combustion can be observed for low load, but no significant difference in combustion phasing can be observed at moderate to high loads. A fuel spray, mixture stoichiometry field and lift-off length model was employed. Linear correlations between the average oxygen equivalence ratio of the fuel-air mixture at the autoignition zone near the lift-off length and brake specific NOx emissions were observed for all load conditions, regardless of fuel type. This confirms that the dominant factor that determines NOx emissions is the ignition event controlled by the oxygen equivalence ratio at the autoignition zone. (C) 2012 Elsevier Ltd. All rights reserved.
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  44. Analysis of the effects of reformate (hydrogen/carbon monoxide) as an assistive fuel on the performance and emissions of used canola-oil biodiesel
    Abstract

    Cecrle, E.; Depcik, C.; Guo, J.; Peltier, E. 2012. Analysis of the effects of reformate (hydrogen/carbon monoxide) as an assistive fuel on the performance and emissions of used canola-oil biodiesel. International Journal of Hydrogen Energy. 37(4) 3510-3527

    Evolving technology and a reoccurring energy crisis creates a continued investigation into the search for sustainable and clean-burning renewable fuels. One possibility is hydrogen that has many desirable qualities such as a low flammability limit promoting ultra-lean combustion, high laminar flame speed for increased thermal efficiency and low emissions. However, past research discovered certain limiting factors in its use such as pre-ignition in spark ignition engines and inability to work as a singular fuel in compression ignition engines. To offset these issues, this work documents manifold injection of a hydrogen/carbon monoxide mixture in a dual-fuel methodology with biodiesel. While carbon monoxide does degrade some of the desirable properties of hydrogen, it acts partially like a diluent to restrict pre-ignition. The result of this mixture addition allows the engine to maintain power while reducing biodiesel fuel consumption with a minimal NOx emissions increase. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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  45. Analyzing the Effects of Methyl Esters Produced from Raw Soybean and Waste Frying Oil on Engine Performance and NOx Emission
    Abstract

    Aksoy, F. 2012. Analyzing the Effects of Methyl Esters Produced from Raw Soybean and Waste Frying Oil on Engine Performance and NOx Emission. Energy Sources Part a-Recovery Utilization and Environmental Effects. 34(1-4) 143-151

    In this study, biodiesel is produced from waste frying oil and raw soybean oil by using a transesterification method. The effects of waste frying and raw soybean methyl esters on engine performance and NOx emissions are investigated. By using waste frying and raw soybean methyl esters, a decrease in engine torque and power and an increase in specific fuel consumption due to low heating values of methyl esters are observed. Since the oxygen content of methyl esters affects NOx development, an increase in Nay emissions is also observed.
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  46. Combined Impact of Biodiesel and Exhaust Gas Recirculation on NOx Emissions in Di Diesel Engines
    Abstract

    Jothithirumal, B.; Jamesgunasekaran, E. 2012. Combined Impact of Biodiesel and Exhaust Gas Recirculation on NOx Emissions in Di Diesel Engines. International Conference on Modelling Optimization and Computing. 381457-1466

    In Diesel engines, NOx formation is a highly temperature-dependent phenomenon and takes place when the temperature in the combustion chamber exceeds 2000K. Therefore, in order to reduce NOx emissions in the exhaust, it is necessary to keep peak combustion temperatures under control.
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  47. Evaluation of the Impacts of Biodiesel and Second Generation Biofuels on NOx Emissions for CARB Diesel Fuels
    Abstract

    Hajbabaei, M.; Johnson, K. C.; Okamoto, R. A.; Mitchell, A.; Pullman, M.; Durbin, T. D. 2012. Evaluation of the Impacts of Biodiesel and Second Generation Biofuels on NOx Emissions for CARB Diesel Fuels. Environmental Science & Technology. 46(16) 9163-9173

    The impact of biodiesel and second generation biofuels on nitrogen oxides (NOx) emissions from heavy-duty engines was investigated using a California Air Resources Board (GARB) certified diesel fuel. Two heavy-duty engines, a 2006 engine with no exhaust aftertreatment, and a 2007 engine with a diesel particle filter (DPF), were tested on an engine dynamometer over four different test cycles. Emissions from soy- and animal-based biodiesels, a hydrotreated renewable diesel, and a gas to liquid (GTL) fuel were evaluated at blend levels from 5 to 100%. NOx emissions consistently increased with increasing biodiesel blend level, while increasing renewable diesel and GTL blends showed NOx emissions reductions with blend level. NOx increases ranged from 1.5% to 6.9% for B20, 6.4% to 18.2% for B50, and 14.1% to 47.1% for B100. The soy-biodiesel showed higher NOx emissions increases compared to the animal-biodiesel. NOx emissions neutrality with the CARB diesel was achieved by blending GTL or renewable diesel fuels with various levels of biodiesel or by using di-tert-butyl peroxide (DTBP). It appears that the impact of biodiesel on NOx emissions might be a more important consideration when blended with CARB diesel or similar fuels, and that some form of NOx mitigation might be needed for biodiesel blends with such fuels.
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  48. Experimental analysis of low temperature combustion mode with diesel and biodiesel fuels: A method for reducing NOx and soot emissions
    Abstract

    Jimenez-Espadafor, F. J.; Torres, M.; Velez, J. A.; Carvajal, E.; Becerra, J. A. 2012. Experimental analysis of low temperature combustion mode with diesel and biodiesel fuels: A method for reducing NOx and soot emissions. Fuel Processing Technology. 10357-63

    One of the main advantages of biodiesel fuels is that almost eliminate carbon dioxide emissions based on the CO2 consumption during plant growth. However it is accepted for most researchers that when burned in diesel engines there is an increase of the NOx emissions when these are compared to the NOx emissions produced by mineral diesel fuel.
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  49. Influence of fuel properties and composition on NOx emissions from biodiesel powered diesel engines: A review
    Abstract

    Varatharajan, K.; Cheralathan, M. 2012. Influence of fuel properties and composition on NOx emissions from biodiesel powered diesel engines: A review. Renewable & Sustainable Energy Reviews. 16(6) 3702-3710

    Biodiesel has proved to be an environment friendly alternative fuel for diesel engine because it can alleviate regulated and unregulated exhaust emissions. However, most researchers have observed a significant increase in NOx emissions with biodiesel when compared to petrodiesel. The exact cause of this increase is still unclear; however, researchers believe that the fuel properties have been shown to effect the emissions of NOx. The present work reviews the effect of fuel properties and composition on NOx emissions from biodiesel fuelled engines. The paper is organised in three sections. The first section deals with the NOx formation mechanisms. In the following section, the reasons for increased NOx emissions of biodiesel fuel are discussed. After this, the influence of composition and fuel properties on NOx emissions from biodiesel fuelled engines has been reviewed. Finally, some general conclusions concerning this problem are summarised and further researches are pointed out. (c) 2012 Elsevier Ltd. All rights reserved.
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  50. Multi Response Optimization of NOx Emission of a Stationary Diesel Engine Fuelled with Crude Rice Bran Oil Methyl Ester
    Abstract

    Saravanan, S.; Nagarajan, G.; Sampath, S. 2012. Multi Response Optimization of NOx Emission of a Stationary Diesel Engine Fuelled with Crude Rice Bran Oil Methyl Ester. Oil & Gas Science and Technology-Revue D Ifp Energies Nouvelles. 67(3) 491-501

    Multi Response Optimization of NO Emission of a Stationary Diesel Engine Fuelled with Crude Rice Bran Oil Methyl Ester - In the present work, an attempt was made to reduce the NOx emission of crude rice bran oil methyl ester without any considerable increase in smoke density, when used as a fuel in a stationary CI engine. Three factors namely, fuel injection timing, Exhaust Gas Recirculation (EGR) and fuel injection pressure were chosen and their combined effect in controlling the NOx of a stationary Diesel engine fuelled with crude rice bran oil methyl ester was investigated. Three levels were chosen in each factor and NO smoke density and brake thermal efficiency were taken as the response variables. Experiments were designed by employing design of experiments method and Taguchi's L-9 orthogonal array was used to conduct the engine tests with different levels of the chosen factors. Multi Response Signal-to-Noise ratio (MRSN) was calculated for the response variables and the optimum combination level of factors was obtained simultaneously using Taguchi's parametric design. Confirmation experiment was conducted for the obtained optimum combination level of factors and the results were compared with normal operating conditions and significant improvement was observed in the response variables.
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  51. Review of the effects of biodiesel on NOx emissions
    Abstract

    Hoekman, S. K.; Robbins, C. 2012. Review of the effects of biodiesel on NOx emissions. Fuel Processing Technology. 96237-249

    Compared to conventional diesel fuel, use of biodiesel is generally found to reduce emissions of hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM); but to increase oxides of nitrogen (NOx) emissions. This paper reviews and summarizes relevant literature regarding the so-called "biodiesel NOx effect, and presents theories" to explain this effect. In modern diesel engines, several factors related to fuel composition and engine control strategies are important, though no single theory provides an adequate explanation of the biodiesel NOx effect under all conditions. There is evidence to suggest that effects on injection timing, ignition delay, adiabatic flame temperature, radiative heat loss, and other combustion phenomena all play some role. The biodiesel NOx effect can be mitigated by modifying engine control settings - particularly by retarding injection timing and increasing exhaust gas recirculation (EGR). The absolute magnitude of the biodiesel NOx effect appears to be reduced with modern engines, although there are cases where the percentage change is still substantial. Sophisticated after-treatment systems required to achieve the 2010 diesel engine emissions standards do not appear to be significantly affected by use of biodiesel. However, longer term study is warranted, as such systems have only been in commercial use for a short time. (C) 2012 Elsevier B.V. All rights reserved.
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  52. Aldehydes Emissions Measurement and OFP assessment of Biodiesel and its Blends with Kerosene using a Low NOx Gas Turbine Combustor
    Abstract

    Li, H.; Altaher, M. A.; Andrews, G. E. 2011. Aldehydes Emissions Measurement and OFP assessment of Biodiesel and its Blends with Kerosene using a Low NOx Gas Turbine Combustor. Proceedings of the Asme Turbo Expo 2011, Vol 2, Pts a and B. 671-680

    There is more interest of using biodiesel fuels derived from vegetable oil or animal fats as alternative fuels for both diesel and gas turbine engines. This is mainly due to the potential benefits on CO2 reductions and renewable. Regulated emissions of biodiesel and its blends are widely studied in diesel engines and some gas turbine engines. However, there is a knowledge gap of lack of information about non-regulated pollutants such as carbonyl compounds (aldehydes etc). This paper assessed aldehydes emissions under atmospheric pressure and 600K using a radial swirler industrial low NOx gas turbine combustor. A comparison was made between B100 (100% WME), B20 (80% Kerosene: 20% WME) and pure Kerosene. A FTIR was used to determine aldehydes including formaldehyde, acetaldehyde and acrolein. OFP (Ozone Formation Potential) of formaldehyde emissions were assessed for these three fuels. The results showed that formaldehyde was the most prevalent aldehyde species for B100, B20 and kerosene, accounted for up to 50%. The aldehydes decreased as equivalence ratio increased due to the increased flame temperatures. A strong correlation between aldehydes emissions and flame temperatures was observed.
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  53. Combustion Analysis and Study on Smoke and Nox Emissions of Diesel and Biodiesel Fueled Ci Engines with Ethanol Blends
    Abstract

    Iranmanesh, M. 2011. Combustion Analysis and Study on Smoke and Nox Emissions of Diesel and Biodiesel Fueled Ci Engines with Ethanol Blends. Proceedings of the Asme Internal Combustion Engine Division Fall Technical Conference (Icef). 1069-1077

    Diesel engines suffer from high amount of soot, particulate matter and nitrogen oxides emissions in spite of their advantages such as high thermal efficiency, low CO and HC emissions. The use of Biodiesel in conventional diesel engines results in a substantial reduction of HC, CO and PM. Its higher cetane number improves the ignition quality. However it suffers from cold starting problems and increased NOx emissions when compared with diesel fuel. Reduction of NOx emissions and particulate matter simultaneously is quite difficult due to the Soot/NOx trade off. In this investigation, tests were conducted on a single cylinder DI diesel engine fueled with neat diesel and biodiesel as baseline fuel and addition of 5 to 20% ethanol on a volume basis in steps of 5 vol.% as a bio-resource supplementary oxygenated fuel to analyze the combustion and emissions characteristics. The results have shown a simultaneous reduction of NOx and smoke emissions in comparison with baseline fuels. A global overview of the results has shown that the 15% ethanol addition to diesel and biodiesel fuel produce the lowest smoke opacity. Meanwhile the lowest amount of NOx emissions belongs to the 10% and 15% ethanol addition to diesel and biodiesel respectively.
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  54. Correlation of the NOx emission and exhaust gas temperature for biodiesel
    Abstract

    AL-Shemmeri, T. T.; Oberweis, S. 2011. Correlation of the NOx emission and exhaust gas temperature for biodiesel. Applied Thermal Engineering. 31(10) 1682-1688

    This paper presents an algorithm which correlates nitrogen oxides emitted and the combustion flame temperature during the combustion of biodiesel. An iterative process is used to determine the flame temperature taking into account the phenomenon of dissociation. The results of the algorithm are presented for different blends and air-to-fuel ratios. These predicted results are compared with laboratory tests conducted in the present study on a stationary diesel engine run on different blends of biodiesel. Within the range of tests carried out, the NOx emissions from biodiesel and its blends proved to be higher than those of petro-diesel fuel. Furthermore, in this study a strong correlation was found relating the NOx emissions and the flame temperature. (C) 2011 Elsevier Ltd. All rights reserved.
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  55. Irrigation Power Unit Performance, Efficiency, and Nox Emissions with Petroleum Diesel, Biodiesel, and Biodiesel Blends
    Abstract

    Kulkarni, S.; Johnson, D. M.; Davis, J. A.; Kennon, D. 2011. Irrigation Power Unit Performance, Efficiency, and Nox Emissions with Petroleum Diesel, Biodiesel, and Biodiesel Blends. Applied Engineering in Agriculture. 27(2) 217-222

    This study compared performance, fuel efficiency, and NOX emissions of a 67-kW irrigation power unit fueled with No. 2 ULSD petroleum diesel (D2), a 20% biodiesel blend (B20), a 50% biodiesel blend (B50), and neat biodiesel (B100) at rated engine speed (2400 rpm) and at typical pumping speed (1800 rpm). At rated speed, there were no differences between D2 and B20 in engine torque, power, or brake specific fuel consumption. There were no differences between the four fuels in thermal efficiency or brake specific NOX emissions. At 1800 rpm there were no differences between D2 and B20 in engine power or torque; however, torque and power decreased with B50 and B100. Brake specific fuel consumption increased as the percentage of biodiesel increased, but there was no difference between the four fuels in thermal efficiency. Finally, there was no difference between D2 and the biodiesel blends or neat biodiesel in brake specific NOX emissions. Based on these results, B20 is recommended as the optimal biodiesel blend for this and similar irrigation power units.
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  56. Mitigation of NOx emissions from a jatropha biodiesel fuelled DI diesel engine using antioxidant additives
    Abstract

    Varatharajan, K.; Cheralathan, M.; Velraj, R. 2011. Mitigation of NOx emissions from a jatropha biodiesel fuelled DI diesel engine using antioxidant additives. Fuel. 90(8) 2721-2725

    Biodiesel offers cleaner combustion over conventional diesel fuel including reduced particulate matter, carbon monoxide and unburned hydrocarbon emissions. However, several studies point to slight increase in NOx emissions (about 10%) for biodiesel fuel compared with conventional diesel fuel. Use of antioxidant additives is one of the most cost-effective ways to mitigate the formation of prompt NOx. In this study, the effect of antioxidant additives on NOx emissions in a jatropha methyl ester fuelled direct injection diesel engine have been investigated experimentally and compared. A survey of literature regarding the causes of biodiesel NOx effect and control strategies is presented. The antioxidant additives L-ascorbic acid, a tocopherol acetate, butylated hydroxytoluene, p-phenylenediamine and ethylenediamine were tested on computerised Kirloskar-make 4 stroke water cooled single cylinder diesel engine of 4.4 kW rated power. Results showed that antioxidants considered in the present study are effective in controlling the NOx emissions of biodiesel fuelled diesel engines. A 0.025%-m concentration of p-phenylenediamine additive was optimal as NOx levels were substantially reduced in the whole load range in comparison with neat biodiesel. However, hydrocarbon and CO emissions were found to have increased by the addition of antioxidants. (C) 2011 Elsevier Ltd. All rights reserved.
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  57. NOx and Soot Emissions Numerical Simulation of Diesel Engine Fueled with Biodiesel
    Abstract

    Ge, J. L.; Tang, D.; Chen, H.; Liu, S. J. 2011. NOx and Soot Emissions Numerical Simulation of Diesel Engine Fueled with Biodiesel. Materials Processing Technology. 337603-607

    The three dimensional numerical simulation on NOx and soot emissions was carried out on 186 FA diesel engine fueled with pure diesel and B20 fuel using CFD software Fire v2008 and the generating rule and distribution of NOx and soot of two fuel was described. Through comparison of the measured indicator diagrams, it verified the accuracy of the model. Based on the simulation of the original diesel engine fueling with B20 fuel, the swirl ratio and injection advance angle are optimized and it proposes technical programs to reduce two kinds of emissions simultaneously, which is optimized of NOx and soot emissions, when the swirl ratio is 2.7 and injection advance angle is 352.5 degrees.
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  58. Preparation of Palm Oil Biodiesel and Effect of Various Additives on NOx Emission Reduction in B20: An Experimental Study
    Abstract

    Vedaraman, N.; Puhan, S.; Nagarajan, G.; Velappan, K. C. 2011. Preparation of Palm Oil Biodiesel and Effect of Various Additives on NOx Emission Reduction in B20: An Experimental Study. International Journal of Green Energy. 8(3) 383-397

    In this study palm biodiesel was prepared from palm oil by transesterification and subsequently different blends (B20, B30, and B40) with diesel were prepared and tested in a standard diesel engine. From the engine test result, B20 was found to be an optimum blend ratio based on engine performance and emissions. The test result shows that the exhaust emissions such as CO and HC are reduced with B20 by 28% and 30%, respectively, compared to diesel. The NOX emissions are almost the same as diesel fuel. In order to reduce NOX emission, a small quantity of different additives namely methanol, ethanol, distilled water, and diethyl ether were added to B20 and evaluated in a standard diesel engine for performance and emissions characteristics. Among all the additives with B20, B20 with 2% distilled water shows the lowest NOX emission and this may be due to lower combustion temperature compared to other additives.
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  59. EVALUATION OF COMBUSTION AND EMISSIONS USING BIODIESEL AND BLENDS WITH KEROSENE IN A LOW NOx GAS TURBINE COMBUSTOR
    Abstract

    Li, H.; Altaher, M.; Andrews, G. E. 2010. EVALUATION OF COMBUSTION AND EMISSIONS USING BIODIESEL AND BLENDS WITH KEROSENE IN A LOW NOx GAS TURBINE COMBUSTOR. Proceedings of the Asme Turbo Expo 2010, Vol 1. 545-553

    Biofuels offer reduced CO(2) emissions for both industrial and aero gas turbines. Industrial applications are more practical due to low temperature waxing problems at altitude. Any use of biofuels in industrial gas turbines must also achieve low NOx and this paper investigates the use of biofuels in a low NOx radial swirler, as used in some industrial low NOx gas turbines. A waste cooking oil derived methyl ester biodiesel (WME) has been tested on a radial swirler industrial low NOx gas turbine combustor under atmospheric pressure and 600K. The pure WME and its blends with kerosene, B20 and B50 (WME:kerosene= 20:80 and 50:50 respectively), and pure kerosene were tested for gaseous emissions and lean extinction as a function of equivalence ratio. The co-firing with natural gas (NG) was tested for kerosene/biofuel blends B20 and B50. The central fuel injection was used for liquid fuels and wall injection was used for NG. The experiments were carried out at a reference Mach number of 0.017. The inlet air to the combustor was heated to 600K. The results show that B20 produced similar NOx at an equivalence ratio of similar to 0.5 and a significant low NOx when the equivalence ratio was increased comparing with kerosene. B50 and B100 produced higher NOx compared to kerosene, which indicates deteriorated mixing due to the poor volatility of the biofuel component. The biodiesel lower hydrocarbon and CO emissions than kerosene in the lean combustion range. The lean extinction limit was lower for B50 and B100 than kerosene. It is demonstrated that B20 has the lowest overall emissions. The co-firing with NG using B20 and B50 significantly reduced NOx and CO emissions.
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  60. Emission profile of 18 carbonyl compounds, CO, CO2, and NOx emitted by a diesel engine fuelled with diesel and ternary blends containing diesel, ethanol and biodiesel or vegetable oils
    Abstract

    Guarieiro, L. L. N.; de Souza, A. F.; Torres, E. A.; de Andrade, J. B. 2009. Emission profile of 18 carbonyl compounds, CO, CO2, and NOx emitted by a diesel engine fuelled with diesel and ternary blends containing diesel, ethanol and biodiesel or vegetable oils. Atmospheric Environment. 43(17) 2754-2761

    The impact of vehicular emissions on air depends, among other factors, on the composition of fuel and the technology used to build the engines. The reduction of vehicular emissions requires changes in the fuel composition, and improving the technologies used in the manufacturing of engines and for the after-treatment of gases. In general, improvements to diesel engines have targeted not only emission reductions, but also reductions in fuel consumption. However, changes in the fuel composition have been shown to be a more rapid and effective alternative to reduce pollution. Some factors should been taken into consideration when searching for an alternative fuel to be used in diesel engines, such as emissions, fuel stability, availability and its distribution, as well as its effects on the engine durability. In this work, 45 fuel blends were prepared and their stability was evaluated. The following mixtures (v/v/v) were stable for the 90-day period and were used in the emission study: diesel/ethanol - 90/10%, diesel/ethanol/soybean biodiesel - 80/15/5%, diesel/ethanol/castor biodiesel - 80/15/5%, diesel/ethanol/residual biodiesel - 80/15/5%, diesel/ethanol/soybean oil - 90/7/3%, and diesel/ethanol/castor oil - 90/7/3%. The diesel/ethanol fuel showed higher reduction of NO, emission at a lower load (2 kW) when compared with pure diesel. The other fuels showed a decrease of NOx emissions in the ranges of 6.9-75% and 4-85% at 1800 rpm and 2000 rpm, respectively. The combustion efficiencies of the diesel can be enhanced by the addition of the oxygenate fuels. like ethanol and biodiesel/vegetable oil, resulting in a more complete combustion in terms of NOx emission. In the case of CO2 the decreases were in the ranges of 5-24% and 4-6% at 1800 rpm and 2000 rpm, respectively. Meanwhile, no differences were observed in CO emission. The carbonyl compounds (CC) studied were formaldehyde, acetaldehyde, propionaldehyde, acrolein, acetone, crotonaldehyde, butyraldehyde, butanone, benzaldehyde, isovaleraldehyde, valeraldehyde, o-toluenaldehyde, m-toluenaldehyde, p-toluenaldehyde, hexaldehyde, octaldehyde, 2,5-dimethyl-benzaldehyde, and decaldehyde. Among them, formaldehyde, acetaldehyde, acetone, and propionaldehyde showed the highest emission concentrations. When ternary blend contains vegetable oil, there is a strong tendency to increase the emissions of the high weight CC and decrease the emissions of the low weight CC. The highest concentration of acrolein was observed when the fuel contains diesel, ethanol and biodiesel. With the exception of NOx, the use of ternary blended fuels resulted on the increase in the emission rates of the studied compounds. (C) 2009 Elsevier Ltd. All rights reserved.
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  61. Investigation of the origin of increased NOx emissions in a heavy-duty compression-ignition engine fueled with soy biodiesel
    Abstract

    Mueller, C. J.; Boehman, A. L.; Martin, G. C. 2009. Investigation of the origin of increased NOx emissions in a heavy-duty compression-ignition engine fueled with soy biodiesel. Abstracts of Papers of the American Chemical Society. 238

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  62. NOx emissions of biodiesel as an alternative diesel fuel
    Abstract

    Canakci, M. 2009. NOx emissions of biodiesel as an alternative diesel fuel. International Journal of Vehicle Design. 50(1-4) 213-228

    As an environmental friendly alternative fuel for compression-ignition (diesel) engines, fatty acid alkyl monoesters, commonly known as biodiesel, are produced from renewable feedstocks Such as vegetable oils and animal fats. Without engine modification, when a diesel engine is fuelled with biodiesel, it provides significant reductions in particulate matter, carbon monoxide and unburned hydrocarbons compared with petroleum-based diesel fuel. In contrast to these reductions, many studies show that the use of biodiesel increases NOx emissions, while only a few papers have reported no changes or reduction in NOx emissions. Various arguments have been used in the literature to explain the increase in NOx emissions when biodiesel is used. This study discusses the combustion characteristics of biodiesel and its fuel properties which are effective in the NOx formation.
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  63. REDUCTION OF NOx EMISSIONS BY CHANGING THE INJECTION TIMING IN A DIESEL ENGINE FUELLED BY BIODIESEL
    Abstract

    Kanellis, P.; Giomataris, V.; Domvrogiannis, A.; Stefanidis, G.; Savvidis, D.; Gogos, M.; Vosniakos, F.; Triandafyllis, J. 2009. REDUCTION OF NOx EMISSIONS BY CHANGING THE INJECTION TIMING IN A DIESEL ENGINE FUELLED BY BIODIESEL. Journal of Environmental Protection and Ecology. 10(4) 1091-1099

    Measurements of power and emissions were made in an indirect injection diesel engine with various mixtures of biodiesel from cottonseed oil and diesel (B0, 1320, 1350, 1380, B 100) under various loads at a chassis dynamometer. Data were taken with changing the injection timing -5 degrees before and +5 degrees from its factory setting that was -10 degrees. Measurements were also taken at three different speeds (30 km/h at second gear, 50 km/h at third gear and 80 km/h at fourth gear). Values of exhaust gases (CO2, NOx, CO, HC, O-2 and smoke) were measured with the biodiesel blends and compared with the values of pure diesel as a fuel. The NOx emissions at -5 degrees were reduced by 5.7% from the factory setting for B100. There was also an increase of NO. and a decrease of smoke with increasing the biodiesel content.
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  64. Simultaneous reduction in cloud point, smoke, and NOx emissions by blending bioethanol into biodiesel fuels and exhaust gas recirculation
    Abstract

    Shudo, T.; Nakajima, T.; Hiraga, K. 2009. Simultaneous reduction in cloud point, smoke, and NOx emissions by blending bioethanol into biodiesel fuels and exhaust gas recirculation. International Journal of Engine Research. 10(1) 15-26

    Palm oil has the important advantage of productivity compared with other vegetable oils such as rapeseed oil and soybean oil. However, the cold flow performance of palm oil methyl ester (PME) is poorer than other vegetable-oil-based biodiesel fuels. Previous research by the current authors has shown that ethanol blending into PME improves the cold flow performance and considerably reduces smoke emission. The reduced smoke may be expected to allow an expansion in the exhaust gas recirculation (EGR) limit and lead to reduced oxides of nitrogen (NOx). This paper experimentally analyses the influence of EGR on smoke and NO, emissions with ethanol-blended PME.
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  65. Soy-Biodiesel Impact on NOx Emissions and Fuel Economy for Diffusion-Dominated Combustion in a Turbo-Diesel Engine Incorporating Exhaust Gas Recirculation and Common Rail Fuel Injection
    Abstract

    Adi, G.; Hall, C.; Snyder, D.; Bunce, M.; Satkoski, C.; Kumar, S.; Garimella, P.; Stanton, D.; Shaver, G. 2009. Soy-Biodiesel Impact on NOx Emissions and Fuel Economy for Diffusion-Dominated Combustion in a Turbo-Diesel Engine Incorporating Exhaust Gas Recirculation and Common Rail Fuel Injection. Energy & Fuels. 235821-5829

    Alternative fuels are gaining importance as a means of reducing petroleum dependence and green house gas emissions. Biodiesel is an attractive renewable fuel; however, it typically results in increased emissions of nitrogen oxides (NOx) relative to petroleum diesel. In order to develop hypotheses for the cause of increased NOx emissions during diffusion-dominated combustion in a modern diesel engine, an effort incorporating both experimental and modeling tasks was conducted. Experiments using a 2007 Cummins diesel engine showed NOx and fuel consumption increases of up to 38% and 13%, respectively, and torque decreases up to 12% for soy-biodiesel. Fuel properties and ignition delay characteristics were implemented in it previously validated engine model to reflect soy-biodiesel. Model predictions are within 3.5%, 7%, and 9.5%, respectively, of experimental engine gas exchange (airflow, charge flow, and exhaust gas recirculation (EGR) fraction), performance (work Output, torque, and fuel consumption), and NOx emission measurements. The experimental and model results for the diffusion combustion-dominated operating conditions considered here suggest that higher biodiesel distillation temperatures and fuel-bound oxygen lead to near stoichiometric equivalence ratios in the rich, premixed portion of the flame as well as higher combustible oxygen mass fractions in the diffusion flame front which together result in increased biodiesel combustion temperatures and NOx formation rates.
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  66. Utilizing Water Emulsification to Reduce Nox and Particulate Emissions Associated with Biodiesel
    Abstract

    Kass, M. D.; Lewis, S. A.; Swartz, M. M.; Huff, S. P.; Lee, D. W.; Wagner, R. M.; Storey, J. M. E. 2009. Utilizing Water Emulsification to Reduce Nox and Particulate Emissions Associated with Biodiesel. Transactions of the Asabe. 52(1) 5-13

    A key barrier limiting extended utilization of biodiesel is higher NOx emissions compared to petrodiesel fuels. The reason for this effect is unclear; but various researchers have attributed this phenomena to the higher liquid bulk modulus associated with biodiesel and the additional heat released during the breaking of C-C double bonds in the methyl ester groups. In this study, water was incorporated into neat biodiesel (B100) as an emulsion in an attempt to lower NOx and particulate matter (PM) emissions. A biodiesel emulsion containing 10wt% water was formulated and evaluated against an ultra-low-sulfur petroleum diesel (ULSD) and neat biodiesel (B100) in a light-duty diesel engine operated at 1500 rpm and at loads of 68 and 102 Nm (50 and 75 ft-lbs). The influence of exhaust gas recirculation (EGR) was also examined. The incorporation of water was found to significantly lower the NOx emissions of B100 while maintaining fuel efficiency when operating at 0% and 27% EGR; however, NOx emissions were observed to increase slightly for the emulsified fuel when the engine load was raised to 102 Nm (75 ft-lbs). The soot fraction of the particulates (as determined using an opacity meter) was much lower for the B100 and B100-water emulsion compared to the ULSD. In contrast, total PM mass (for the three fuel types) was unchanged for the 0% EGR condition but was significantly lower for the B100 and B100-emulsion during the 27% EGR condition compared to the ULSD. Analysis of the emissions and heat release data indicate that water enhances air-fuel premixing to maintain fuel economy and lower soot formation. The exhaust chemistry of the biodiesel base fuels (B100 and water-emulsified B100) was found to be unique in that they contained measurable levels of methyl alkenoates, which were not found for the ULSD. These compounds were formed by the partial cracking of the methyl ester groups during combustion.
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  67. APPLICATION OF DIETHYL ETHER TO REDUCE SMOKE AND NOx EMISSIONS SIMULTANEOUSLY WITH DIESEL AND BIODIESEL FUELED ENGINES
    Abstract

    Iranmanesh, M.; Subrahmanyam, J. P.; Babu, M. K. G. 2008. APPLICATION OF DIETHYL ETHER TO REDUCE SMOKE AND NOx EMISSIONS SIMULTANEOUSLY WITH DIESEL AND BIODIESEL FUELED ENGINES. Imece 2008: Proceedings of the Asme International Mechanical Engineering Congress and Exposition, Vol 3. 77-83

    In this investigation, tests were conducted on a single cylinder DI diesel engine fueled with neat diesel and biodiesel as baseline fuel with addition of 5 to 20% DEE on a volume basis in steps of 5 vol.% as supplementary oxygenated fuel to analyze the simultaneous reduction of smoke and oxides of nitrogen.
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  68. Combining biodiesel and exhaust gas recirculation for reduction in NOx and particulate emissions
    Abstract

    Muncrief, R. L.; Rooks, C. W.; Cruz, M.; Harold, M. P. 2008. Combining biodiesel and exhaust gas recirculation for reduction in NOx and particulate emissions. Energy & Fuels. 22(2) 1285-1296

    The coupled elimination of NO, and particulate matter (PM) in diesel exhaust was investigated by combining biodiesel, exhaust gas recirculation (EGR), and diesel particulate filtration (DPF). The combustion of biodiesel fuels, being oxygenated hydrocarbons, produces less partial oxidation products such as CO, volatile organic hydrocarbons, and particulate soot. EGR requires auxiliary particulate filtration due to the increased soot that is produced while the reliability of the DPF regeneration requires a minimum exhaust temperature and NOx/ PM ratio. We employed a heavy-duty chassis dynamometer system to quantify the synergistic effects of biodiesel, EGR, and soot filtration for a vehicle having a drive cycle with a low exhaust temperature. The biodiesel/ EGR/DPF system performance was assessed in terms of NO, and PM emissions for low-temperature operation. The combination of biodiesel and EGR was shown to produce significantly less NO, and PM for a refuse truck operated at low load. The combination of biodiesel and EGR replaces gas phase 02 from air with nascent oxygen in the fuel, resulting in up to a 40% reduction in both PM and NO, compared to the use of ultralow sulfur diesel (ULSD) without EGR. The decrease in PM and corresponding increase in the NOx/PM ratio has a beneficial effect on DPF operability due to a more favorable oxidation stoichiometry. Another advantage of this system is the possibility of optimizing NOx reduction by increasing the amount of EGR, while staying within the prescribed limits of favorable DPF operation.
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  69. Reducing NOx Emissions from a Biodiesel-Fueled Engine by Use of Low-Temperature Combustion
    Abstract

    Fang, T. G.; Lin, Y. C.; Foong, T. M.; Lee, C. F. 2008. Reducing NOx Emissions from a Biodiesel-Fueled Engine by Use of Low-Temperature Combustion. Environmental Science & Technology. 42(23) 8865-8870

    Biodiesel is popularly discussed in many countries due to increased environmental awareness and the limited supply of petroleum. One of the main factors impacting general replacement of diesel by biodiesel is NOx (nitrogen oxides) emissions. Previous studies have shown higher NOx emissions relative to petroleum diesel in traditional direct-injection (DI) diesel engines. In this study, effects of injection timing and different biodiesel blends are studied for low load [2 bar IMEP (indicated mean effective pressure)] conditions. The results show that maximum heat release rate can be reduced by retarding fuel injection. Ignition and peak heat release rate are both delayed for fuels containing more biodiesel. Retarding the injection to post-TDC (top dead center) lowers the peak heat release and flattens the heat release curve. It is observed that low-temperature combustion effectively reduces NOx emissions because less thermal NOx is formed. Although biodiesel combustion produces more NOx for both conventional and late-injection strategies, with the latter leading to a low-temperature combustion mode, the levels of NOx of B20 (20 vol % soy biodiesel and 80 vol % European low-sulfur diesel), 1350, and B100 all with post-TDC injection are 68.1%, 66.7%, and 64.4%, respectively, lower than pure European low-sulfur diesel in the conventional injection scenario.
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  70. Reducing NOx emissions from a biodiesel-fueled engine by use of low-temperature combustion
    Abstract

    Fang, T.; Lin, Y. C.; Foong, T. M.; Lee, C. F. 2008. Reducing NOx emissions from a biodiesel-fueled engine by use of low-temperature combustion. Environ Sci Technol. 42(23) 8865-70

    Biodiesel is popularly discussed in many countries due to increased environmental awareness and the limited supply of petroleum. One of the main factors impacting general replacement of diesel by biodiesel is NOx (nitrogen oxides) emissions. Previous studies have shown higher NOx emissions relative to petroleum diesel in traditional direct-injection (DI) diesel engines. In this study, effects of injection timing and different biodiesel blends are studied for low load [2 bar IMEP (indicated mean effective pressure)] conditions. The results show that maximum heat release rate can be reduced by retarding fuel injection. Ignition and peak heat release rate are both delayed for fuels containing more biodiesel. Retarding the injection to post-TDC (top dead center) lowers the peak heat release and flattens the heat release curve. It is observed that low-temperature combustion effectively reduces NOx emissions because less thermal NOx is formed. Although biodiesel combustion produces more NOx for both conventional and late-injection strategies, with the latter leading to a low-temperature combustion mode, the levels of NOx of B20 (20 vol % soy biodiesel and 80 vol % European low-sulfur diesel), B50, and B100 all with post-TDC injection are 68.1%, 66.7%, and 64.4%, respectively, lower than pure European low-sulfur diesel in the conventional injection scenario.
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  71. Simultaneous reduction of NOx emission and smoke opacity of biodiesel-fueled engines by port injection of ethanol
    Abstract

    Lu, X. C.; Ma, J. J.; Ji, L. B.; Huang, Z. 2008. Simultaneous reduction of NOx emission and smoke opacity of biodiesel-fueled engines by port injection of ethanol. Fuel. 87(7) 1289-1296

    In the present study, the detailed combustion characteristics and emissions of biodiesel-fueled engines with premixed ethanol by port injection were investigated. The experiments were carried out on a single-cylinder, four-stroke, natural aspirated direct injection engine at a fixed speed. The heat release analysis indicates that, with the introduction of ethanol fuel by port injection, the ignition timing of the overall combustion event delays remarkably, while the maximum heat release rate increases smoothly. At a leaner fuel/air mixture, the peak value of the heat release rate (HRR) increases slightly, the maximum in-cylinder gas pressure and temperature decrease, and the indicated thermal efficiency (ITE) deteriorates with the increase of ethanol proportion. While at a rich fuel/air mixture, with the increase of the ethanol proportion, the maximum HRR increases rapidly, the overall combustion event is completed at an earlier crank angle. Moreover, the maximum values of the HRR reach the peak point in a certain premixed ratio which ranges from 20% to 40%. Also, the ITE reaches the largest value at this operation point. Due to the introduction of the ethanol fuel by port injection, both the NOx emission and smoke opacity decrease to a very low level under overall operation conditions. During the experimental points of this test, NOx and smoke opacity simultaneously decrease about 35-85% compared to those of the neat biodiesel-fueled engines. (c) 2007 Elsevier Ltd. All rights reserved.
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  72. Computational modelling of NOx emissions from biodiesel combustion
    Abstract

    Yuan, W.; Hansen, A. C.; Zhang, Q. 2007. Computational modelling of NOx emissions from biodiesel combustion. International Journal of Vehicle Design. 45(1-2) 12-32

    A detailed numerical spray atomisation, ignition, combustion and NOx formation model was developed for direct injection diesel engines using KIVA-3V code that could be applied to biodiesel fuels and this model was used to investigate the NOx emissions mechanisms of biodiesel compared with diesel fuel. In addition, computational modelling was applied to evaluate strategies for reducing NOx emissions from biodiesel combustion. The physical and thermodynamic properties of biodiesel used in the model were based on fatty acid composition. The model was verified with experimental data from an engine fuelled with diesel fuel, soyabean methyl ester, Yellow Grease Methyl Ester (YGME) and genetically modified soyabean methyl ester. Strategies for reducing NOx emissions from biodiesel combustion were evaluated with the aid of the model. Increasing spray cone angle, retarding start of injection, applying Exhaust Gas Recirculation (EGR) and charge air cooling were all effective approaches to reducing NOx emissions from biodiesel fuel.
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  73. Impact of biodiesel on NOx emissions in a common rail direct injection diesel engine
    Abstract

    Zhang, Y.; Boehman, A. L. 2007. Impact of biodiesel on NOx emissions in a common rail direct injection diesel engine. Energy & Fuels. 21(4) 2003-2012

    The impact of biodiesel on NOx emissions was investigated in a 2.5 L common rail direct injection diesel engine under both low load and high load conditions with different fuel injection strategies. Three fuels were used in this study, an ultralow sulfur diesel fuel (BP15), a blend of 20 vol % biodiesel in BP15 (B20), and a blend of 40 vol % biodiesel in BP15 (B40). Fuel injection timings were held the same for the biodiesel blends and the baseline diesel fuel to eliminate the potential injection timing differences due to the different fuel heating values. According to the needle lift profiles obtained from the needle lift sensor, no measurable injection timing differences were observed between the biodiesel blends and the baseline diesel fuel. Biodiesel blends were found to generally produce slightly lower NOx emissions than the baseline diesel fuel at the low load condition. Under the high load condition, evidently higher NOx emissions for biodiesel blends were observed under both single and double injection conditions. Overall, biodiesel diesel blends and the baseline diesel fuel had very similar heat release rate profiles. Injection system parameters were adjusted to reduce the increased NOx emissions for B20. Retarding injection timing under single injection conditions was found to be the more effective approach to reduce the NOx emissions than using pilot injection with retarded main injection in terms of NOx and fuel consumption tradeoff. Under the low load condition, the pilot injection strategy led to substantially reduced NOx emissions. When the performance of the 40 vol % biodiesel blend under various exhaust gas recirculation (EGR) rate conditions was investigated, the biodiesel blend showed no further combustion deterioration compared to the baseline diesel fuel. A low NOx and fuel-efficient engine operating condition was achieved with the 40 vol % biodiesel blend.
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  74. NOx and particulate matter (PM) emissions reduction potential by biodiesel usage
    Abstract

    Kegl, B. 2007. NOx and particulate matter (PM) emissions reduction potential by biodiesel usage. Energy & Fuels. 21(6) 3310-3316

    The transport in many countries is the most significant source for NOx and particulate matter (PM) emissions. Therefore, the possibility of reducing NOx and PM emissions is experimentally investigated using biodiesel and some of its blends with mineral diesel. Attention is focused on the optimal bus diesel engine adjustments for each tested fuel. The obtained engine characteristics are compared to each other by considering the 13 modes of the European stationary cycle test. The optimal injection pump timings are determined with the aim of reducing harmful emissions, while keeping other engine characteristics within acceptable limits. The optimal fuel blend is suggested, and the harmful emissions (NOx, PM, CO, unburned hydrocarbon, and smoke) reduction is estimated.
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  75. Effect of combustion air dilution by water vapor or nitrogen on NOx emission in a premixed turbulent natural gas flame: An experimental study
    Abstract

    Landman, M. J.; Derksen, M. A. F.; Kok, J. B. W. 2006. Effect of combustion air dilution by water vapor or nitrogen on NOx emission in a premixed turbulent natural gas flame: An experimental study. Combustion Science and Technology. 178(4) 623-634

    A study of the effects of combustion air dilution by water vapor or nitrogen on NOx emission in a premixed turbulent natural gas flame was performed for lean conditions. NOx concentrations were measured with dry air, water vapor dilution or nitrogen dilution of the combustion air at varying air factor at three different power/pressure settings. Results showed for all cases a significant reduction in NOx emission as an effect of combustion air dilution by water vapor and nitrogen for constant T-ad. The results also showed that the reducing effect of water vapor dilution is larger than the reducing effect of nitrogen dilution. It is therefore concluded that water vapor dilution of the combustion air not only reduces NOx emission in premixed turbulent flames by lowering flame temperature and oxygen deficiency, but also by chemical action
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  76. Experimental investigation of control of NOx emissions in biodiesel-fueled compression ignition engine
    Abstract

    Agarwal, D.; Sinha, S.; Agarwal, A. K. 2006. Experimental investigation of control of NOx emissions in biodiesel-fueled compression ignition engine. Renewable Energy. 31(14) 2356-2369

    Biodiesel is an alternative fuel consisting of the alkyl esters of fatty acids from vegetable oils or animal fats. Vegetable oils are produced from numerous oil seed crops (edible and non-edible), e.g., rapeseed oil, linseed oil, rice bran oil, soybean oil, etc. Research has shown that biodiesel-fueled engines produce less carbon monoxide (CO), unburned hydrocarbon (HC), and particulate emissions compared to mineral diesel fuel but higher NOx emissions. Exhaust gas recirculation (EGR) is effective to reduce NOx from diesel engines because it lowers the flame temperature and the oxygen concentration in the combustion chamber. However, EGR results in higher particulate matter (PM) emissions. Thus, the drawback of higher NOx emissions while using biodiesel may be overcome by employing EGR. The objective of current research work is to investigate the usage of biodiesel and EGR simultaneously in order to reduce the emissions of all regulated pollutants from diesel engines. A two-cylinder, air-cooled, constant speed direct injection diesel engine was used for experiments. HCs, NOx, CO, and opacity of the exhaust gas were measured to estimate the emissions. Various engine performance parameters such as thermal efficiency, brake specific fuel consumption (BSFC), and brake specific energy consumption (BSEC), etc. were calculated from the acquired data. Application of EGR with biodiesel blends resulted in reductions in NOx emissions without any significant penalty in PM emissions or BSEC. (c) 2006 Elsevier Ltd. All rights reserved.
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  77. Reformulating biodiesel to reduce NOx emissions
    Abstract

    Hess, M. A.; Haas, M. J.; Foglia, T. A. 2006. Reformulating biodiesel to reduce NOx emissions. Abstracts of Papers of the American Chemical Society. 231

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  78. Effect of antioxidant addition on NOx emissions from biodiesel
    Abstract

    Hess, M. A.; Haas, M. J.; Foglia, T. A.; Marmer, W. N. 2005. Effect of antioxidant addition on NOx emissions from biodiesel. Energy & Fuels. 19(4) 1749-1754

    Biodiesel is a renewable, domestically produced fuel that has been shown to reduce particulate, hydrocarbon, and carbon monoxide emissions from diesel engines. Biodiesel produced from certain feedstocks, however, has been shown to cause an increase in nitrogen oxides (NOx), which is of particular concern in urban areas that are subject to strict environmental regulations. There are several pathways proposed that try to account for NOx formation during the combustion process, one of which is the Fenimore mechanism. In the Fenimore mechanism, it is postulated that fuel radicals formed during the combustion process react with nitrogen from the air to form NOx. We proposed that if these radical reactions could be terminated, NOx production from biodiesel combustion would decrease. To test this hypothesis, we investigated the ability of antioxidants, which are capable of terminating these kinds of radical reactions, to reduce NOx levels in biodiesel exhaust. Several antioxidants added to a 20% soy biodiesel/80% diesel fuel blend (1320) at a concentration of 1000 ppm were screened using a small, minimally instrumented diesel engine to test their ability to reduce NO, emissions. The engine used for these studies was a single cylinder, direct-injection, air-cooled, naturally aspirated Yanmar engine. The NO and NO2 in the exhaust stream were quantified using electrochemical sensors, and differences in NOx emissions from the combustion of B20 with and without antioxidant were compared. The addition of butylated hydroxyanisole or butylated hydroxytoluene reduced NOx emissions, but the other antioxidants tested did not have this effect.
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  79. EU proposes new PM and NOx emission limits
    Abstract

    Christen, K. 2005. EU proposes new PM and NOx emission limits. Environmental Science & Technology. 39(19) 398A-398A

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  80. Spray, Ignition, and Combustion Modeling of Biodiesel Fuels for Investigating NOx Emissions
    Abstract

    Yuan, W.; C. Hansen, A.; E. Tat, M.; H. Van Gerpen, J.; Tan, Z. 2005. Spray, Ignition, and Combustion Modeling of Biodiesel Fuels for Investigating NOx Emissions. Transactions of the ASAE. 48(3) 933

    The objective of this research was to develop a detailed numerical spray atomization, ignition, and combustion model for direct-injection diesel engines using KIVA3V code that could be applied to biodiesel fuels for investigating NOx emissions. Several modified or recalibrated submodels were incorporated into KIVA3V, including a KH-RT spray breakup model, a Shell ignition model, and a single-step kinetic combustion model. This modified model was applied to a John Deere 4045T direct-injection diesel engine fueled by a soybean methyl ester, a yellow grease methyl ester, and No. 2 diesel fuel. The output of the model was in close agreement with the experimental measurements of cylinder pressure and heat release rate from this engine. It was predicted from the modeling results that the two biodiesel fuels had shorter ignition delay and higher overall cylinder temperatures than diesel fuel. The in-cylinder spray analysis indicated that the soybean methyl ester had slightly longer penetration than diesel fuel, but the yellow grease methyl ester had shorter penetration than diesel fuel. Fewer particle numbers were predicted for the two biodiesel fuels. Both soybean methyl ester and yellow grease methyl ester had more widespread high-temperature distribution areas than diesel fuel, which could account for the increases in NOx emissions typically measured for biodiesel fuels.
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  81. The effects of injection timing on NOx emissions of a low heat rejection indirect diesel injection engine
    Abstract

    Parlak, A.; Yasar, H.; Hasimoglu, C.; Kolip, A. 2005. The effects of injection timing on NOx emissions of a low heat rejection indirect diesel injection engine. Applied Thermal Engineering. 25(17-18) 3042-3052

    Higher NO, is one of the major problems to be overcomed in a low heat rejection (LHR) diesel engine as insulation leads to an increase in combustion temperature about 200-250 degrees C compared to an identical standard (STD) diesel engine. High combustion temperatures alter optimum injection timing of a LHR engine. With the proper adjustment of the injection timing, it is possible to partially offset the adverse effect of insulation on heat release rate and hence to obtain improved performance and lower NOx. However, the injection timing and brake specific fuel consumption (BSFC) trade-off must be considered together in performance and NO., emission point of view. In this study, optimum injection timing was found with 4 crank angle (34 degrees CA) retarded before top dead centre (BTDC) in LHR diesel engine in comparison to that of STD diesel engine (380 CA BTDC). When the LHR engine was operated with the injection timing of the 38 crank angle, which is the optimum value of the STD engine, it was shown that NOx emission increased about 15%. However, when the injection timing was retarded to 34 degrees CA in the LHR case, it was observed a decrease on the NOx emissions with about 40% and the brake specific fuel consumption (BSFC) with about 6% compared to that of the STD case. Thus, by retarding the injection timing, an additional 1.5% saving in fuel consumption was obtained. (c) 2005 Elsevier Ltd. All rights reserved
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  82. Effect of antioxidant addition on NOx emissions from biodiesel.
    Abstract

    Hess, M. A.; Haas, M. J.; Foglia, T. A.; Marmer, W. N. 2004. Effect of antioxidant addition on NOx emissions from biodiesel.. Abstracts of Papers of the American Chemical Society. 228U679-U679

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  83. Eliminating the NOx emissions increase associated with biodiesel.
    Abstract

    Chapman, E. M.; Hile, M.; Pague, M.; Song, J. H.; Boehman, A. L. 2003. Eliminating the NOx emissions increase associated with biodiesel.. Abstracts of Papers of the American Chemical Society. 226U539-U539

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