轻型柴油机起动过程瞬态喷油量控制策略研究

摘要

为一高压共轨轻型柴油机提出了基于目标转速变化规律的起动过程瞬态喷油量的控制策略和确定方法,并与定油量和油量MAP控制方式进行了对比.结果表明:油量MAP控制方式在起动过程中虽NOx排放低,过渡转速波动小,但平均燃烧效率较低,HC和CO排放高;而定油量控制方式平均燃烧效率较高,HC和CO排放低,但NOx和CO2排放高,且过渡转速波动大.新的控制策略可根据起动过程瞬态转速变化特性精确控制喷油量,使各瞬态燃烧效率高,有效降低CO2,HC,CO和NOx排放,且起动到怠速可实现圆滑过渡.%A control strategy for and the determination method of transient fuel injection quantity in starting process based on the changing rule of target speed is proposed for a high-pressure common-rail light diesel engine, which is then compared with constant fuel quantity control and fuel quantity MAP control. The results show that with MAP control mode, although the NOx emission in starting process is low and the speed fluctuation in transition peri-od is small, but its average combustion efficiency is low and the emissions of HC and CO are higher;With constant fuel quantity control mode, the average combustion efficiency is higher, the emissions of HC and CO are lower, but NOx and CO2 emissions are higher and the speed fluctuation in transition period is increased;While the new control strategy can accurately control fuel injection quantity according to the characteristics of the transient speed in starting process, resulting in higher transient combustion efficiency, lower emissions of CO2 , HC, CO and NOx and smoot-her transition from starting to idling.