The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Zuohua Huang - One of the best experts on this subject based on the ideXlab platform.
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Effect of Compression Ratio on Cycle-by-Cycle Variations in a Natural Gas Direct Injection Engine
Energy & Fuels, 2009Co-Authors: Jianjun Zheng, Zuohua Huang, Jinhua Wang, Bin Wang, Dezhong Ning, Yingjia ZhangAbstract:Cycle-by-cycle variations of a natural gas direct-injection spark ignition engine at different compression ratios were investigated. The results show that the lean burn limit of the natural-gas direct injection engine can be extended to a larger overall excess air ratio compared with that of the homogeneous charge natural gas engine. The coefficient of variations (CoV) of indicated Mean Effective Pressure decreases with the increase of compression ratio. However, CoV of indicated Mean Effective Pressure is increased at high engine load when compression ratio is larger than 12. The cycle-by-cycle variations are more clearly demonstrated in CoV of indicated Mean Effective Pressure rather than in CoV of cylinder peak Pressure. Average values of flame development duration, main combustion duration, and total combustion duration are decreased and combustion is improved with increasing compression ratio. This is the reason for decreasing cycle-by-cycle variations in the natural gas direct-injection engine. Bett...
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cycle by cycle variations in a spark ignition engine fueled with natural gas hydrogen blends combined with egr
International Journal of Hydrogen Energy, 2009Co-Authors: Bin Huang, Bing Liu, Erjiang Hu, Zuohua Huang, Jianjun Zheng, Deming JiangAbstract:Abstract Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak Pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated Mean Effective Pressure and EGR ratio. Slight influence of EGR ratio on indicated Mean Effective Pressure is observed at low EGR ratios while large influence of EGR ratio on indicated Mean Effective Pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios.
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Cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with EGR
International Journal of Hydrogen Energy, 2009Co-Authors: Bin Huang, Bing Liu, Erjiang Hu, Zuohua Huang, Jianjun Zheng, Deming JiangAbstract:Abstract Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak Pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated Mean Effective Pressure and EGR ratio. Slight influence of EGR ratio on indicated Mean Effective Pressure is observed at low EGR ratios while large influence of EGR ratio on indicated Mean Effective Pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios.
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Experimental study on combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends combining with EGR
International Journal of Hydrogen Energy, 2009Co-Authors: Erjiang Hu, Bing Liu, Zuohua Huang, Jianjun Zheng, Xiaolei GuAbstract:Abstract An experimental study on the effect of hydrogen fraction and EGR rate on the combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends was investigated. The results show that flame development duration, rapid combustion duration and total combustion duration are increased with the increase of EGR rate and decreased with the increase of hydrogen fraction in the blends. Hydrogen addition shows larger influence on flame development duration than that on rapid combustion duration. The coefficient of variation of the indicated Mean Effective Pressure increases with the increase of EGR rate. And hydrogen addition into natural gas decreases the coefficient of variation of the indicated Mean Effective Pressure, and this Effectiveness becomes more obviously at high EGR rate. Engine fueled with natural gas–hydrogen blends combining with proper EGR rate can realize the stable low temperature combustion in gas engine.
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experimental study on combustion characteristics of a spark ignition engine fueled with natural gas hydrogen blends combining with egr
International Journal of Hydrogen Energy, 2009Co-Authors: Erjiang Hu, Bing Liu, Zuohua Huang, Jianjun Zheng, Xiaolei GuAbstract:Abstract An experimental study on the effect of hydrogen fraction and EGR rate on the combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends was investigated. The results show that flame development duration, rapid combustion duration and total combustion duration are increased with the increase of EGR rate and decreased with the increase of hydrogen fraction in the blends. Hydrogen addition shows larger influence on flame development duration than that on rapid combustion duration. The coefficient of variation of the indicated Mean Effective Pressure increases with the increase of EGR rate. And hydrogen addition into natural gas decreases the coefficient of variation of the indicated Mean Effective Pressure, and this Effectiveness becomes more obviously at high EGR rate. Engine fueled with natural gas–hydrogen blends combining with proper EGR rate can realize the stable low temperature combustion in gas engine.
Deming Jiang - One of the best experts on this subject based on the ideXlab platform.
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Cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with EGR
International Journal of Hydrogen Energy, 2009Co-Authors: Bin Huang, Bing Liu, Erjiang Hu, Zuohua Huang, Jianjun Zheng, Deming JiangAbstract:Abstract Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak Pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated Mean Effective Pressure and EGR ratio. Slight influence of EGR ratio on indicated Mean Effective Pressure is observed at low EGR ratios while large influence of EGR ratio on indicated Mean Effective Pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios.
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cycle by cycle variations in a spark ignition engine fueled with natural gas hydrogen blends combined with egr
International Journal of Hydrogen Energy, 2009Co-Authors: Bin Huang, Bing Liu, Erjiang Hu, Zuohua Huang, Jianjun Zheng, Deming JiangAbstract:Abstract Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak Pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated Mean Effective Pressure and EGR ratio. Slight influence of EGR ratio on indicated Mean Effective Pressure is observed at low EGR ratios while large influence of EGR ratio on indicated Mean Effective Pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios.
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Study on cycle-by-cycle variations of combustion in a natural-gas direct-injection engine:
Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2008Co-Authors: Zuohua Huang, Deming Jiang, Ke Zeng, Qiuwang WangAbstract:In this paper, the cycle-by-cycle variations of a compressed-natural-gas (CNG) direct-injection (DI) engine were investigated. The results show that the CNG DI engine has a better lean burn capability, and misfire cycles and partial burn cycles exist when the engine operates at small equivalence ratio (w ,0.4). Meanwhile, the indicated Mean Effective Pressure (IMEP) has a low value, and the high value of the coefficient of variation in the IMEP is presented in comparison with those operating at a high equivalence ratio. Cycles with a high maximum cylinder Pressure correspond to the cycles of fast burning, and parameter interdependence is observed between the maximum cylinder gas Pressure and its correspond- ing crank angle, between the maximum rate of Pressure rise and its corresponding crank angle, and between the maximum cylinder Pressure and the indicated Mean Effective Pressure. Better parameter interdependence exists between the maximum cylinder Pressure and the flame- developing period, between the maximum cylinder Pressure and the rapid-burning period, and between the accumulated heat release amount per cycle and the indicated Mean Effective Pressure. A small variation in the flame-developing duration will lead to a large variation in the rapid-burning duration under lean mixture combustion; the slow flame propagation speed of the lean mixture combustion is considered to lead to this phenomenon.
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Combustion characteristics of a direct-injection engine fueled with natural gas–hydrogen blends under different ignition timings
Fuel, 2007Co-Authors: Zuohua Huang, Jinrong Yu, Bing Liu, Ke Zeng, Jinhua Wang, Deming JiangAbstract:Abstract In this paper, combustion characteristics of a direct-injection spark-ignited engine fueled with natural gas–hydrogen blends under various ignition timings and lean mixture condition were investigated. The results show that the ignition timing has significant influence on engine performance, combustion and emissions. The time intervals between the end of fuel injection and ignition timing are very sensitive to direct-injection gas engine combustion. The turbulence in combustion chamber generated by the fuel jet maintains high and relatively strong mixture stratification is presented when decreasing the time intervals between the end of injection and the ignition timing, giving fast burning rate, high brake Mean Effective Pressure, high thermal efficiency and short combustion durations. For specific ignition timing, the brake Mean Effective Pressure and the Effective thermal efficiency increase and combustion durations decrease with the increase of hydrogen fraction in natural gas. Exhaust HC concentration decreases and exhaust NO x concentration increase with advancing the ignition timing while the exhaust CO gives little variation under various ignition timings.
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combustion characteristics of a direct injection engine fueled with natural gas hydrogen blends under different ignition timings
Fuel, 2007Co-Authors: Zuohua Huang, Jinrong Yu, Bing Liu, Ke Zeng, Jinhua Wang, Deming JiangAbstract:Abstract In this paper, combustion characteristics of a direct-injection spark-ignited engine fueled with natural gas–hydrogen blends under various ignition timings and lean mixture condition were investigated. The results show that the ignition timing has significant influence on engine performance, combustion and emissions. The time intervals between the end of fuel injection and ignition timing are very sensitive to direct-injection gas engine combustion. The turbulence in combustion chamber generated by the fuel jet maintains high and relatively strong mixture stratification is presented when decreasing the time intervals between the end of injection and the ignition timing, giving fast burning rate, high brake Mean Effective Pressure, high thermal efficiency and short combustion durations. For specific ignition timing, the brake Mean Effective Pressure and the Effective thermal efficiency increase and combustion durations decrease with the increase of hydrogen fraction in natural gas. Exhaust HC concentration decreases and exhaust NO x concentration increase with advancing the ignition timing while the exhaust CO gives little variation under various ignition timings.
Bing Liu - One of the best experts on this subject based on the ideXlab platform.
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cycle by cycle variations in a spark ignition engine fueled with natural gas hydrogen blends combined with egr
International Journal of Hydrogen Energy, 2009Co-Authors: Bin Huang, Bing Liu, Erjiang Hu, Zuohua Huang, Jianjun Zheng, Deming JiangAbstract:Abstract Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak Pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated Mean Effective Pressure and EGR ratio. Slight influence of EGR ratio on indicated Mean Effective Pressure is observed at low EGR ratios while large influence of EGR ratio on indicated Mean Effective Pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios.
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Cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with EGR
International Journal of Hydrogen Energy, 2009Co-Authors: Bin Huang, Bing Liu, Erjiang Hu, Zuohua Huang, Jianjun Zheng, Deming JiangAbstract:Abstract Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas–hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak Pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated Mean Effective Pressure and EGR ratio. Slight influence of EGR ratio on indicated Mean Effective Pressure is observed at low EGR ratios while large influence of EGR ratio on indicated Mean Effective Pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios.
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Experimental study on combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends combining with EGR
International Journal of Hydrogen Energy, 2009Co-Authors: Erjiang Hu, Bing Liu, Zuohua Huang, Jianjun Zheng, Xiaolei GuAbstract:Abstract An experimental study on the effect of hydrogen fraction and EGR rate on the combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends was investigated. The results show that flame development duration, rapid combustion duration and total combustion duration are increased with the increase of EGR rate and decreased with the increase of hydrogen fraction in the blends. Hydrogen addition shows larger influence on flame development duration than that on rapid combustion duration. The coefficient of variation of the indicated Mean Effective Pressure increases with the increase of EGR rate. And hydrogen addition into natural gas decreases the coefficient of variation of the indicated Mean Effective Pressure, and this Effectiveness becomes more obviously at high EGR rate. Engine fueled with natural gas–hydrogen blends combining with proper EGR rate can realize the stable low temperature combustion in gas engine.
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experimental study on combustion characteristics of a spark ignition engine fueled with natural gas hydrogen blends combining with egr
International Journal of Hydrogen Energy, 2009Co-Authors: Erjiang Hu, Bing Liu, Zuohua Huang, Jianjun Zheng, Xiaolei GuAbstract:Abstract An experimental study on the effect of hydrogen fraction and EGR rate on the combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends was investigated. The results show that flame development duration, rapid combustion duration and total combustion duration are increased with the increase of EGR rate and decreased with the increase of hydrogen fraction in the blends. Hydrogen addition shows larger influence on flame development duration than that on rapid combustion duration. The coefficient of variation of the indicated Mean Effective Pressure increases with the increase of EGR rate. And hydrogen addition into natural gas decreases the coefficient of variation of the indicated Mean Effective Pressure, and this Effectiveness becomes more obviously at high EGR rate. Engine fueled with natural gas–hydrogen blends combining with proper EGR rate can realize the stable low temperature combustion in gas engine.
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Study of cycle-by-cycle variations of a spark ignition engine fueled with natural gas–hydrogen blends
International Journal of Hydrogen Energy, 2008Co-Authors: Jinhua Wang, Bing Liu, Hao Chen, Zuohua HuangAbstract:Abstract Cycle-by-cycle variations of a spark ignition engine fueled with natural gas–hydrogen blends with hydrogen volumetric fraction of 0%, 12%, 23%, 30% and 40% were studied. The effect of hydrogen addition on cycle-by-cycle variations of the natural gas engine was analyzed. The results showed that the peak cylinder Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure increased and their corresponding cycle-by-cycle variations decreased with the increase of hydrogen fraction at lean mixture operation. The interdependency between the combustion parameters and the corresponding crank angle tended to be strongly correlated with the increase of hydrogen fraction under lean mixture operation. Coefficient of variation of the indicated Mean Effective Pressure gave a low level and is slightly influenced by hydrogen addition under the stoichiometric and relatively rich mixture operation while it decreased remarkably with the increase of hydrogen fraction under the lean mixture operation. The excessive air ratio at CoV imep = 10% extended to the leaner mixture side with the increase of hydrogen fraction and this indicated that the engine lean operating limit could be extended with hydrogen addition.
Myoung Ho Sunwoo - One of the best experts on this subject based on the ideXlab platform.
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robust indicated Mean Effective Pressure and combustion lambda feedback control for lean nox trap regeneration in a 2 2 l common rail direct injection diesel engine
Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2015Co-Authors: Myoung Ho SunwooAbstract:To meet stringent Euro-6 emission regulations, a lean NOx trap (LNT) catalyst should be considered to Effectively abate NOx emissions. This LNT catalyst should be periodically regenerated without deteriorating driving quality and also satisfy emission constraints, such as CO, low particulate matter or smoke, and low O2 during the regeneration phase. As a Means of reductant delivery, in-cylinder post fuel injection with a feedforward (FF) control has been applied due to its simple implementation in an engine management system (EMS). However, with this method, it is difficult to satisfy the driving quality and emission constraints during the transition to or out of the regeneration phase. To solve this problem, we propose a novel LNT regeneration control method using an indicated Mean Effective Pressure (IMEP) and a combustion lambda feedback (FB) control combined with the FF control. For the precise FB control of the post injection timing, among the location of the second rate of heat release (ROHR) peak, the magnitude of the second ROHR peak, and IMEP, the IMEP was selected as a control parameter because of its lowest cyclic variation. In addition, the exhaust lambda control was applied for the accurate FB control of the post injection quantity. The proposed method was implemented in an in-house EMS. The performance in several engine tests indicated that the torque fluctuation was minimized and all emission constraints were Effectively satisfied. Furthermore, this method was also robust with regard to the thermal disturbance.
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Robust Indicated Mean Effective Pressure and Combustion Lambda Feedback Control for Lean NO x Trap Regeneration in a 2.2 L Common Rail Direct Injection Diesel Engine
Journal of Engineering for Gas Turbines and Power, 2015Co-Authors: Hyunjun Lee, Manbae Han, Myoung Ho SunwooAbstract:To meet stringent Euro-6 emission regulations, a lean NOx trap (LNT)\ncatalyst should be considered to Effectively abate NOx emissions. This\nLNT catalyst should be periodically regenerated without deteriorating\ndriving quality and also satisfy emission constraints, such as CO, low\nparticulate matter or smoke, and low O-2 during the regeneration phase.\nAs a Means of reductant delivery, in-cylinder post fuel injection with a\nfeedforward (FF) control has been applied due to its simple\nimplementation in an engine management system (EMS). However, with this\nmethod, it is difficult to satisfy the driving quality and emission\nconstraints during the transition to or out of the regeneration phase.\nTo solve this problem, we propose a novel LNT regeneration control\nmethod using an indicated Mean Effective Pressure (IMEP) and a\ncombustion lambda feedback (FB) control combined with the FF control.\nFor the precise FB control of the post injection timing, among the\nlocation of the second rate of heat release (ROHR) peak, the magnitude\nof the second ROHR peak, and IMEP, the IMEP was selected as a control\nparameter because of its lowest cyclic variation. In addition, the\nexhaust lambda control was applied for the accurate FB control of the\npost injection quantity. The proposed method was implemented in an\nin-house EMS. The performance in several engine tests indicated that the\ntorque fluctuation was minimized and all emission constraints were\nEffectively satisfied. Furthermore, this method was also robust with\nregard to the thermal disturbance.
Jinhua Wang - One of the best experts on this subject based on the ideXlab platform.
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Effect of Compression Ratio on Cycle-by-Cycle Variations in a Natural Gas Direct Injection Engine
Energy & Fuels, 2009Co-Authors: Jianjun Zheng, Zuohua Huang, Jinhua Wang, Bin Wang, Dezhong Ning, Yingjia ZhangAbstract:Cycle-by-cycle variations of a natural gas direct-injection spark ignition engine at different compression ratios were investigated. The results show that the lean burn limit of the natural-gas direct injection engine can be extended to a larger overall excess air ratio compared with that of the homogeneous charge natural gas engine. The coefficient of variations (CoV) of indicated Mean Effective Pressure decreases with the increase of compression ratio. However, CoV of indicated Mean Effective Pressure is increased at high engine load when compression ratio is larger than 12. The cycle-by-cycle variations are more clearly demonstrated in CoV of indicated Mean Effective Pressure rather than in CoV of cylinder peak Pressure. Average values of flame development duration, main combustion duration, and total combustion duration are decreased and combustion is improved with increasing compression ratio. This is the reason for decreasing cycle-by-cycle variations in the natural gas direct-injection engine. Bett...
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Study of cycle-by-cycle variations of a spark ignition engine fueled with natural gas–hydrogen blends
International Journal of Hydrogen Energy, 2008Co-Authors: Jinhua Wang, Bing Liu, Hao Chen, Zuohua HuangAbstract:Abstract Cycle-by-cycle variations of a spark ignition engine fueled with natural gas–hydrogen blends with hydrogen volumetric fraction of 0%, 12%, 23%, 30% and 40% were studied. The effect of hydrogen addition on cycle-by-cycle variations of the natural gas engine was analyzed. The results showed that the peak cylinder Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure increased and their corresponding cycle-by-cycle variations decreased with the increase of hydrogen fraction at lean mixture operation. The interdependency between the combustion parameters and the corresponding crank angle tended to be strongly correlated with the increase of hydrogen fraction under lean mixture operation. Coefficient of variation of the indicated Mean Effective Pressure gave a low level and is slightly influenced by hydrogen addition under the stoichiometric and relatively rich mixture operation while it decreased remarkably with the increase of hydrogen fraction under the lean mixture operation. The excessive air ratio at CoV imep = 10% extended to the leaner mixture side with the increase of hydrogen fraction and this indicated that the engine lean operating limit could be extended with hydrogen addition.
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study of cycle by cycle variations of a spark ignition engine fueled with natural gas hydrogen blends
International Journal of Hydrogen Energy, 2008Co-Authors: Jinhua Wang, Bing Liu, Hao Chen, Zuohua HuangAbstract:Abstract Cycle-by-cycle variations of a spark ignition engine fueled with natural gas–hydrogen blends with hydrogen volumetric fraction of 0%, 12%, 23%, 30% and 40% were studied. The effect of hydrogen addition on cycle-by-cycle variations of the natural gas engine was analyzed. The results showed that the peak cylinder Pressure, the maximum rate of Pressure rise and the indicated Mean Effective Pressure increased and their corresponding cycle-by-cycle variations decreased with the increase of hydrogen fraction at lean mixture operation. The interdependency between the combustion parameters and the corresponding crank angle tended to be strongly correlated with the increase of hydrogen fraction under lean mixture operation. Coefficient of variation of the indicated Mean Effective Pressure gave a low level and is slightly influenced by hydrogen addition under the stoichiometric and relatively rich mixture operation while it decreased remarkably with the increase of hydrogen fraction under the lean mixture operation. The excessive air ratio at CoV imep = 10% extended to the leaner mixture side with the increase of hydrogen fraction and this indicated that the engine lean operating limit could be extended with hydrogen addition.
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Combustion characteristics of a direct-injection engine fueled with natural gas–hydrogen blends under different ignition timings
Fuel, 2007Co-Authors: Zuohua Huang, Jinrong Yu, Bing Liu, Ke Zeng, Jinhua Wang, Deming JiangAbstract:Abstract In this paper, combustion characteristics of a direct-injection spark-ignited engine fueled with natural gas–hydrogen blends under various ignition timings and lean mixture condition were investigated. The results show that the ignition timing has significant influence on engine performance, combustion and emissions. The time intervals between the end of fuel injection and ignition timing are very sensitive to direct-injection gas engine combustion. The turbulence in combustion chamber generated by the fuel jet maintains high and relatively strong mixture stratification is presented when decreasing the time intervals between the end of injection and the ignition timing, giving fast burning rate, high brake Mean Effective Pressure, high thermal efficiency and short combustion durations. For specific ignition timing, the brake Mean Effective Pressure and the Effective thermal efficiency increase and combustion durations decrease with the increase of hydrogen fraction in natural gas. Exhaust HC concentration decreases and exhaust NO x concentration increase with advancing the ignition timing while the exhaust CO gives little variation under various ignition timings.
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combustion characteristics of a direct injection engine fueled with natural gas hydrogen blends under different ignition timings
Fuel, 2007Co-Authors: Zuohua Huang, Jinrong Yu, Bing Liu, Ke Zeng, Jinhua Wang, Deming JiangAbstract:Abstract In this paper, combustion characteristics of a direct-injection spark-ignited engine fueled with natural gas–hydrogen blends under various ignition timings and lean mixture condition were investigated. The results show that the ignition timing has significant influence on engine performance, combustion and emissions. The time intervals between the end of fuel injection and ignition timing are very sensitive to direct-injection gas engine combustion. The turbulence in combustion chamber generated by the fuel jet maintains high and relatively strong mixture stratification is presented when decreasing the time intervals between the end of injection and the ignition timing, giving fast burning rate, high brake Mean Effective Pressure, high thermal efficiency and short combustion durations. For specific ignition timing, the brake Mean Effective Pressure and the Effective thermal efficiency increase and combustion durations decrease with the increase of hydrogen fraction in natural gas. Exhaust HC concentration decreases and exhaust NO x concentration increase with advancing the ignition timing while the exhaust CO gives little variation under various ignition timings.