发动机停机后曲轴停止相位的研究

Engine Crankshaft Position after Shutdown

针对发动机在停机过程中由于缸内气体压力的作用出现的曲轴反转现象,研究发动机停机后曲轴停止的位置对于缸内直喷汽油机实施起动—停止控制策略的重要意义。在Jetta1.6 L发动机上的研究结果表明:发动机停机后处于压缩行程的活塞停在80°CA BTDC的概率较大,约占50%;发动机是否发生反转主要取决于转动动能衰减到0时缸内气体负力矩的大小;采用两个具有一定相位差的光电传感器可以判断曲轴是否反转并检测停机后曲轴的位置。

For the crankshaft reversal that caused by cylinder gas pressure during the process of stopping the engine, the significance of crankshaft position after shutdown for gasoline direct injection （GDI） applying start-stop control strategy was researched. The research was carried out on a Jettal. 6 L engine. The results show that the piston in the compression stroke tends to stop at around 80 ℃A BTDC, which probability is about 50%. Engine reversal depends on the cylinder gas negative torque when the engine rotational kinetic energy decays to 0. Using two photoelectric sensors with a certain phase difference, the crankshaft reversal and the crankshaft position after shutdown can be judged and detected.