柴油机恒转速增转矩瞬态工况的燃烧过程分析及其对烟度的影响

Effect of Combustion Parameters on Diesel Engine Smoke Opacity Under Constant Speed and Increasing Torque Transient Operating Condition

采用自行设计的瞬态工况控制及测量系统,对增压中冷柴油机进行了恒转速增转矩瞬态工况下发动机的空燃比、消光烟度及示功图参数的测试.试验结果表明:随转矩增加率的上升,空燃比减小,引起混合气变浓,燃烧恶化;燃烧始点后移,而燃烧持续期延长;预混燃烧比明显下降.上述原因导致了在恒转速增转矩瞬态工况下,随转矩增加率的升高,排气烟度上升.

The air-fuel ratio, smoke opacity and in-cylinder pressure of a TCA diesel engine under constant speed and increasing torque transient operating conditions were tested by a home-made control and measurement system. The conclusions can be drawn that with the rise of the torque increasing rate the air-fuel ratio decreased rapidly, the combustion start point delayed, the combustion duration prolonged, and the premixed combustion rate reduced. All the factors mentioned above make the diesel engine smoke opacity increased with the torque increasing rate.