轻型车用柴油机起动怠速过渡过程瞬态喷油量控制

Injection quantity control strategy for starting to idling transition of light duty diesel engine

提出了一种基于目标转矩的起动过程瞬态喷油量控制方法,并在2.8T型高压共轨直喷柴油机上与恒定油量控制方法以及油量MAP式控制方法进行了对比试验。结果表明:基于MAP式控制方法在起动过程中虽然NO_x排放少,但燃烧效率也低,HC和CO排放较高;恒定油量控制方法在起动过程中能保持较高的燃烧效率,HC和CO排放较低,但NO排放多,而且起动过渡到怠速时转速波动较大;本文控制策略可根据起动过程中转速的变化精确控制瞬态喷油量,因此起动过程中燃油消耗量最少、燃烧效率高、CO_2排放最低,在HC和CO以及NO_x排放水平较低的前提下,可以实现起动过程平稳地过渡到怠速状态。

A target torque based injection quantity control strategy for diesel engine starting is presented,which is compared with constant fuel quantity control method and MAP based control method by experiments on a 2.8Thigh pressure common rail diesel engine.The results show that,with the MAP based control,the NOxemission is lower but the HC and CO emissions are higher and the combustion efficiency is lower.The combustion efficiency of the constant fuel quantity control is higher and the HC and CO emissions are lower,but the NOxemission is higher and the speed fluctuation is serious during the transition from start to idle.With the proposed control strategy,the injection quantity is accurately controlled according to the instantaneous torque demand,so the fuel consumption is lower and the combustion efficiency is higher,meanwhile,the CO,HC and NOx emissions are lower,the transition from start to idle is smooth.