Oxygen fuels have broad application prospects and great potential for realizing efficient and clean combustion,and hence this study applies diesel/n-butanol blends to explore the influence of split-injection strategy ...Oxygen fuels have broad application prospects and great potential for realizing efficient and clean combustion,and hence this study applies diesel/n-butanol blends to explore the influence of split-injection strategy on combustion and emission characteristics.Simultaneously,changing the way of exhaust gas recirculation(EGR)gas introduction forms uneven in-cylinder components distribution,and utilizing EGR stratification optimizes the combustion process and allows better emission results.The results show that the split-injection strategy can reduce the NO_(x)emissions and keep smoke opacity low compared with the single injection,but the rise in accumulation mode particles is noticeable.NO_(x)emissions show an upward trend as the injection interval expands,while soot emissions are significantly reduced.The increase in pre-injection proportion causes the apparent low-temperature heat release,and the two-stage heat release can be observed during the process of main combustion heat release.More pre-injection mass makes NO_(x)gradually increase,but smoke opacity reaches the lowest point at 15%pre-injection proportion.EGR stratification can optimize the emission results under the split injection strategy,especially the considerable suppression of accumulation mode particulate emissions.Above all,fuel stratification coupled with EGR stratification is beneficial for further realizing the in-cylinder purification of pollutants.展开更多
废气再循环(exhaust gas recirculation)是降低柴油机尾气排放中的氮氧化物(NOX)以及降低天然气发动机爆震的一项非常有效的措施,在废气再循环中,EGR冷却器是其中的一个关键零部件。本文在发动机试验台架上研究了EGR冷却器进水流量、EG...废气再循环(exhaust gas recirculation)是降低柴油机尾气排放中的氮氧化物(NOX)以及降低天然气发动机爆震的一项非常有效的措施,在废气再循环中,EGR冷却器是其中的一个关键零部件。本文在发动机试验台架上研究了EGR冷却器进水流量、EGR冷却器进水温度、EGR冷却器进气温度以及EGR冷却器进气流量对EGR冷却器出气温度的影响,以便为发动机匹配最合适的EGR冷却器。试验结果表明:水流量变化对EGR冷却器的出气温度不敏感,发动机无法使用减少或者增加水流量的方法来降低或者提高EGR冷却器的出气温度;EGR冷却器的进水温度每增加1℃,EGR冷却器的出气温度升高0.9℃;EGR冷却器的进气温度每升高10℃,EGR冷却器的出气温度升高0.7℃;EGR冷却器的进气流量每升高10kg/h,EGR冷却器的出气温度升高1.2℃。展开更多
在一款涡轮增压汽油缸内直喷(gasoline direct injection,GDI)汽油机上进行了高压(HP)废气再循环(exhaust gas recirculation,EGR)和低压(LP)EGR对发动机和增压器性能影响的试验研究。分别对比了HP EGR和LP EGR系统在外特性和部分负荷...在一款涡轮增压汽油缸内直喷(gasoline direct injection,GDI)汽油机上进行了高压(HP)废气再循环(exhaust gas recirculation,EGR)和低压(LP)EGR对发动机和增压器性能影响的试验研究。分别对比了HP EGR和LP EGR系统在外特性和部分负荷工况对发动机燃烧、油耗、进排气的影响及增压器相应的工况变化,并分析了出现这些变化的原因。结果表明,汽油机EGR系统能够优化缸内燃烧,减少泵气损失,从而降低油耗。低压EGR系统在部分负荷工况热效率比高压EGR更高,主要原因为低压EGR系统的涡轮增压器可利用的尾气能量更多,且进入发动机的废气温度较低,能进一步优化缸内燃烧。展开更多
以一台高压共轨轻型柴油机为样机,研究废气再循环(exhaust gas recirculation,EGR)和喷油正时协同作用对发动机燃烧特性、燃油消耗率、氮氧化物(NOx)和HC排放的影响。研究结果表明:随着EGR率增大,缸内最大压力有所下降,瞬时放热率峰值...以一台高压共轨轻型柴油机为样机,研究废气再循环(exhaust gas recirculation,EGR)和喷油正时协同作用对发动机燃烧特性、燃油消耗率、氮氧化物(NOx)和HC排放的影响。研究结果表明:随着EGR率增大,缸内最大压力有所下降,瞬时放热率峰值有所减小。随着喷油提前角增加,缸内最大压力增大,瞬时放热率峰值先增大后减小。EGR率与缸内最大压力降幅、瞬时放热率峰值降幅均具有较好的线性关系。随着EGR率的增大和喷油提前角的减小,NOx排放降低,燃油耗增加,而且存在一个最佳的EGR率和喷油提前角的组合区域使HC排放达到最低。为了实现降低NOx排放的同时有效控制燃油消耗率和避免HC排放升高,低负荷时选择高EGR率并结合大喷油提前角的控制策略;中等负荷时选择适中EGR率结合适中喷油提前角的控制策略。展开更多
基金Projects(51476069,51676084)supported by the National Natural Science Foundation of ChinaProject(2019C058-3)supported by the Jilin Provincial Industrial Innovation Special Guidance Fund Project,China+1 种基金Project(20180101059JC)supported by the Jilin Provincial Science and Technology Development Plan Project,ChinaProject(2020C025-2)supported by the Jilin Provincial Specific Project of Industrial Technology Research&Development,China。
文摘Oxygen fuels have broad application prospects and great potential for realizing efficient and clean combustion,and hence this study applies diesel/n-butanol blends to explore the influence of split-injection strategy on combustion and emission characteristics.Simultaneously,changing the way of exhaust gas recirculation(EGR)gas introduction forms uneven in-cylinder components distribution,and utilizing EGR stratification optimizes the combustion process and allows better emission results.The results show that the split-injection strategy can reduce the NO_(x)emissions and keep smoke opacity low compared with the single injection,but the rise in accumulation mode particles is noticeable.NO_(x)emissions show an upward trend as the injection interval expands,while soot emissions are significantly reduced.The increase in pre-injection proportion causes the apparent low-temperature heat release,and the two-stage heat release can be observed during the process of main combustion heat release.More pre-injection mass makes NO_(x)gradually increase,but smoke opacity reaches the lowest point at 15%pre-injection proportion.EGR stratification can optimize the emission results under the split injection strategy,especially the considerable suppression of accumulation mode particulate emissions.Above all,fuel stratification coupled with EGR stratification is beneficial for further realizing the in-cylinder purification of pollutants.
文摘废气再循环(exhaust gas recirculation)是降低柴油机尾气排放中的氮氧化物(NOX)以及降低天然气发动机爆震的一项非常有效的措施,在废气再循环中,EGR冷却器是其中的一个关键零部件。本文在发动机试验台架上研究了EGR冷却器进水流量、EGR冷却器进水温度、EGR冷却器进气温度以及EGR冷却器进气流量对EGR冷却器出气温度的影响,以便为发动机匹配最合适的EGR冷却器。试验结果表明:水流量变化对EGR冷却器的出气温度不敏感,发动机无法使用减少或者增加水流量的方法来降低或者提高EGR冷却器的出气温度;EGR冷却器的进水温度每增加1℃,EGR冷却器的出气温度升高0.9℃;EGR冷却器的进气温度每升高10℃,EGR冷却器的出气温度升高0.7℃;EGR冷却器的进气流量每升高10kg/h,EGR冷却器的出气温度升高1.2℃。
文摘在一款涡轮增压汽油缸内直喷(gasoline direct injection,GDI)汽油机上进行了高压(HP)废气再循环(exhaust gas recirculation,EGR)和低压(LP)EGR对发动机和增压器性能影响的试验研究。分别对比了HP EGR和LP EGR系统在外特性和部分负荷工况对发动机燃烧、油耗、进排气的影响及增压器相应的工况变化,并分析了出现这些变化的原因。结果表明,汽油机EGR系统能够优化缸内燃烧,减少泵气损失,从而降低油耗。低压EGR系统在部分负荷工况热效率比高压EGR更高,主要原因为低压EGR系统的涡轮增压器可利用的尾气能量更多,且进入发动机的废气温度较低,能进一步优化缸内燃烧。
文摘以一台高压共轨轻型柴油机为样机,研究废气再循环(exhaust gas recirculation,EGR)和喷油正时协同作用对发动机燃烧特性、燃油消耗率、氮氧化物(NOx)和HC排放的影响。研究结果表明:随着EGR率增大,缸内最大压力有所下降,瞬时放热率峰值有所减小。随着喷油提前角增加,缸内最大压力增大,瞬时放热率峰值先增大后减小。EGR率与缸内最大压力降幅、瞬时放热率峰值降幅均具有较好的线性关系。随着EGR率的增大和喷油提前角的减小,NOx排放降低,燃油耗增加,而且存在一个最佳的EGR率和喷油提前角的组合区域使HC排放达到最低。为了实现降低NOx排放的同时有效控制燃油消耗率和避免HC排放升高,低负荷时选择高EGR率并结合大喷油提前角的控制策略;中等负荷时选择适中EGR率结合适中喷油提前角的控制策略。
