摘要
以一台高压级为可变几何截面的增压器(VGT)的两级涡轮增压重型柴油机为研究对象,研究负荷烟度试验(ELR)测试循环中恒转速突加载的瞬态过程中喷油系统及EGR的控制策略对响应性能和排放的影响.发现单次喷射的转矩响应时间比两次喷射缩短26.1%,但两次喷射模式的烟度峰值比单次喷射降低了33.3%,NOx峰值降低了21.9%.两次喷射的主喷和后喷燃油比例确定时,主喷最终定时提前2°,CA,将缩短42.6%的转矩响应时间;而后喷定时提前3,°,CA,将引起烟度峰值增大91.7%.此外,基于转矩响应及排放的需求,开发了EGR阀晚开的控制策略,EGR阀开启时刻过早和过晚都将引起转矩响应的恶化,EGR阀开启过早将会产生过高的烟度峰值,EGR阀开启过晚将产生大量的NOx排放.故合理匹配喷油系统和EGR阀控制策略是实现恒转速突加载过程高转矩响应和低排放的重要技术手段之一.
Effect of EGR and fuel injection on engine torque response and emissions under load transient operation of constant speed as the ELR test has been investigated in a two-stage turbocharged heavy-duty diesel engine with VGT. It was found that the torque response time decreased by 26.1% through single fuel injection comparing with that of two pulse-injection. By using two pulse-injection,the smoke peak reduces by 33.3% and NOx peak reduces by 21.9%. Furthermore,it was found that while keeping constant fuel injection proportion,the change in 2,°,CA of the final main injection timing will change the torque response time by 42. 6% and 3,°,CA retarding of the second injection timing can decrease the smoke peak by 91.7%. To meet the demand for fast torque response and lower emissions,the strategy of retardation of EGR valve was adopted. Over early openning of EGR valve would raise the peak of smoke while too late EGR valve openning would increase the NOx emissions. Optimization on matching fuel injection and EGR was proved to be the important technical approach for achieving high torque response and low emissions under load transient operation of constant engine speed.
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2014年第5期385-392,共8页
Transactions of Csice
基金
国家高技术研究发展计划"863"资助项目(2012AA111714)
关键词
发动机控制
瞬态策略
瞬态响应
排放
engine control
engine transient operation
transient response
emissions
