液化气单一燃料电控发动机的起动控制策略

Start control strategy in electronically controlled LPG port injection spark ignition engine

分别在初始温度为9℃、15℃、20℃的条件下对LPG发动机的冷起动特性进行了试验研究,并与汽油发动机进行了对比。试验结果表明:LPG发动机成功起动所需的混合气浓度比汽油发动机的稀。汽油发动机首次着火循环所需的起动初始脉宽约是稳定怠速时的6.9倍,LPG的为2.5倍;由于较低的充气效率,发动机使用LPG燃料成功起动时的初始节气门开度及能够稳定在怠速转速下的节气门开度比使用汽油燃料的大。与汽油发动机相比,LPG发动机具有较好的起动特性。

The cold start tests were performed comparatively for the liquid petroleum gas(LPG) and gasoline engines at the ambient temperatures of 9,15 and 20 ℃ respectively.The results showed that the fuel-air mixture suitable for the LPG engine start is leaner than that of the gasoline engine.The first fuel injection pulse width for the start of the gasoline engine is about 6.9 times of that at the normal idle condition,while it needs only 2.5 times for the LPG engine.Because of the lower volumetric efficiency,the initial throttle openings for the start and idling of the LPG engine are larger than those of the gasoline engine.Generally speaking,the start behavior of the LPG engine is better than that of the gasoline engine.