两种米勒循环对柴油机性能的影响

The Influence of Two Miller Cycles on Diesel Engine Performance

基于某轻型柴油机使用GT-Power软件建立一维仿真模型,通过试验数据与仿真数据进行验证分析,确定仿真模型的精度,同时研究两种米勒循环对柴油机性能的影响。结果表明,当柴油机工作在额定转速下,采用进气门早关(EIVC)策略,缸内压力和有效燃油消耗率随米勒度的增加而下降,NOx排放随米勒度的增加而减少;采用进气门晚关(LIVC)策略,缸内压力随米勒度的增加而减小,有效燃油消耗率随米勒度的增加而上升,NOx随米勒度的增加先增加后减少;当柴油机工作在1 800 r/min转速下,采用EIVC策略,缸内压力随米勒度的增加而下降,有效燃油消耗率随米勒度的增加而上升,NOx排放随米勒度的增加先增加后减少;采用LIVC策略,缸内压力随米勒度的增加而下降,有效燃油消耗率随米勒度的增加而上升,NOx排放随米勒度的增加而减少。

A one-dimensional simulation model based on light diesel engine is established by using GT-Power software.The accuracy of the simulation model is verified and analyzed by the test data and simulation data.The effects of two Miller cycles on diesel engine performance are studied.The results show that when the engine runs at rated speed and adopts early intake valve closure(EIVC)strategy,the cylinder pressure and brake specific fuel consumption decrease with the increase of Miller degree,and the NOx emission decreases with the increase of Miller degree.When late intake valve closure(LIVC)strategy is adopted,the cylinder pressure decreases with the increase of Miller cycle,the brake specific fuel consumption increases with the increase of Miller degree,and NOx increases first and then decreases with the increase of Miller degree.When the diesel engine is working at 1800 r/min,the EIVC strategy is adopted,the cylinder pressure decreases with the increase of the Miller cycle degree,the braking specific fuel consumption increases with the increase of the Miller cycle degree,and the NOx emission increases first and then decreases with the increase of the Miller cycle degree.Using LIVC strategy,the cylinder pressure decreases with the increase of Miller degree,the braking specific fuel consumption increases with the increase of Miller degree,and the NOx emission decreases with the increase of Miller degree.