天然气发动机燃烧制动性能仿真研究

Simulation of CNG Engine Combustion Brake Performance

利用GT-Power仿真软件建立某一型号发动机模型,研究点火时刻、转速和减压气门运行参数对发动机燃烧制动性能的影响。研究结果表明:随着点火时刻的提前,发动机制动功率呈线性增加;点火时刻一定时,发动机转速越高制动功率越大,减压气门升程越高制动功率也越大。当转速一定时,每个减压气门升程都对应一个最佳气门提前角使得制动功率的峰值最大,且最佳气门提前角随着气门升程的增大而减小;当升程一定时,每个转速都对应一个最佳气门提前角使得制动功率的峰值最大,且最佳气门提前角随着转速增大而增大。当气门升程为4mm、转速为2 400r/min时,最大制动功率可达137kW,可达发动机标定功率的1.7倍。

In order to simulate the effects of ignition timing,speed,and release valve operating parameters on engine combustion brake performance,the GT-Power software was used to establish a model of a certain engine and the simulation was then conducted.The results show that the engine braking power increases linearly with the advance of the ignition timing.At each ignition timing,the higher the engine speed,the greater the braking power;the higher the release valve lift,the greater the braking power.When the engine speed remains constant,each release valve lift has an optimal valve advance angle where the braking power reaches peak,and the optimal valve advance angle decreases as the release valve lift increases.When the release valve lift is fixed,each engine speed has an optimal release valve advance angle where the braking power is the maximum,and the optimal valve advance angle increases with the engine speed.At4 mm valve lift and 2 400 r/min engine speed,the maximum braking power is 137 kW,1.7 times the rated engine power.