使用缸压信息的柴油机低温燃烧闭环控制

Closed-loop control of low temperature combustion in diesel engines with cylinder pressure information

在柴油机上采用低温燃烧技术,可以获得比传统压燃方式更低的氮氧化物和颗粒物排放。为了解决柴油机低温燃烧不稳定和各缸均匀性差的问题,基于缸压信息,构建了双控制单元的分布式控制系统,设计了平均指示压力(indicated mean effective pressure,IMEP)和50%放热曲轴位置(50%of the mass fraction burned,MFB50或CA50)双闭环的控制方法。实验结果表明:基于缸压信息反馈的燃烧闭环控制系统,在低负荷低温燃烧工况点,能够有效控制各缸的燃烧状态不均匀的状况,并大幅度改善燃烧不稳定的现象;在高负荷低温燃烧工况点,可以将各缸的CA50和IMEP控制在目标值附近。

Low temperature combustion will lower nitric oxides and particulate matter emissions more than conventional compression ignition. However, low temperature combustion results in unstable combustion and cylinder-to-cylinder variations. Thus, a distributed control system is developed with a two input-two-output control algorithm based on cylinder pressure feedback information. Experimental results show that this closed-loop combustion control system improves cylinder-to cylinder uniformity and combustion stability at low load operating conditions for low temperature combustion and controls the 50%of the mass fraction burned （MFB50 or CA50） and indicated mean effective pressure （IMEP） at their set points for high load operating conditions.