进气增压拓展汽油HCCI发动机高负荷的试验研究

Extending HCCI High Load Operation of Gasoline Engine by Intake Boosting

在1台四冲程汽油缸内直喷式发动机上研究了进气增压对HCCI高负荷拓展的影响。试验结果表明,HCCI发动机所能达到的最大IMEP从自然吸气条件下的0.41 MPa升高到增压条件下的0.74 MPa。随着增压压力的增大,燃烧持续期明显拉长,燃烧温度大幅度下降,NOx排放大幅度降低。但在高增压低负荷下,由于混合气过稀,HCCI燃烧恶化,CO排放大幅度升高。

The effect of intake boosting on extending homogeneous charge compression ignition（HCCI） high load operation was investigated in a 4-stroke gasoline direct injection engine. The test results show that the maximum indicated mean effective pressure（IMEP） of HCCI at high load increases significantly from 0.41 MPa at natural aspiration to 0.74 MPa at boost condition. As the boost pressure increases, the duration of combustion increases, and the combustion temperature decreases significantly, the NOx emissions are greatly reduced with the increase of boost pressure. But at higher boost pressure and leaner air fuel ratio, the HCCI combustion deteriorates and the CO emissions increase dramatically.