基于汽油/柴油双阶段燃烧模式对低温阶段燃烧及排放性能的影响  

Influence of Gasoline/Diesel Dual-Stage Combustion Mode on Emissions and Performances During Low Temperature Stage

作　　者：韩永强[1] 柴嘉鸿 刘忠长[1] 田径[1] 许允[1] 刘佳会[1] 

机构地区：[1]吉林大学汽车仿真与控制国家重点实验室,吉林长春130022

出　　处：《内燃机学报》2017年第6期502-508,共7页Transactions of Csice

基　　金：国家自然科学基金资助项目(51576089);吉林大学研究生创新基金资助项目(2016026)

摘　　要：在一台高压共轨柴油机进气总管上加装汽油喷射系统,汽油采用进气道喷射形成预混合气,柴油采用缸内大角度预喷并引燃汽油.试验以降低NOx排放和消光烟度为主要目标,探究汽油/柴油双阶段燃烧模式的汽油喷射量、柴油预喷正时、柴油预喷量对低温阶段燃烧及排放特性的影响,并通过对燃烧、排放及经济性综合考量构建喷油参数优化策略.结果表明:引入汽油后的燃烧过程呈现两阶段放热,实现了柴油着火时刻可控;增加汽油喷射量可以有效强化缸内油气混合,使主放热率峰值升高,有助于燃烧完全;该燃烧模式的低温阶段避免了传统柴油机NOx和消光烟度出现的折中关系,消光烟度处于低水平范围,均低于3%,;适度提前柴油预喷正时或减少柴油预喷量能同时降低NOx排放和消光烟度,但CO和HC会出现一定程度恶化.A gasoline injection system was added to the intake manifold of a high pressure common rail diesel engine. The gasoline was supplied by port injection to form pre-mixture in the cylinder, and the diesel injected into the cylinder with a large advanced injection angle was compressed to auto-ignite the gasoline based mixture. This gasoline/diesel dual fuel combustion experiment was carried out to investigate the effects of gasoline injection quantity, diesel pilot injection timing and quantity on the combustion process and emission characteristics during low tempera- ture stage with the aim to reduce NOx emissions and smoke opacity simultaneously. Optimized strategy about injection parameters was built based on comprehensive analyses of the combustion, emissions and fuel economy. Results show that due to the introduction of gasoline, the combustion process demonstrates a distinct dual-stage heat release and the diesel auto-ignition timing becomes controllable. Increasing gasoline injection quantity can enhance fuel-air mixing process in the cylinder effectively, leading to an increase in the peak heat release rate and a promotion in complete combustion. During the low temperature stage of the gasoline/diesel duel fuel combustion mode, the trade-off relationship between NOx and smoke opacity in traditional diesel engine is broken and an ultra-low level of smoke opacity emissions, less than 3%, is obtained. Advancing diesel injection timing or decreasing diesel pilot injection quantity properly can reduce NOx emissions and smoke opacity simultaneously, but CO and HC emissions deteriorate to a certain extent.

关 键 词：汽油 柴油 双阶段燃烧 预喷 排放 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]