进气门晚关策略对发动机经济性及炭烟排放的影响

摘要

针对增压直喷汽油机因降低几何压缩比而制约了燃油经济性改善的问题，通过应用进气门晚关（LIVC）策略，有效地抑制了高压缩比直喷汽油机的爆震并改善了其燃油经济性，但试验中发现，LIVC策略造成了高炭烟排放，为了进一步改进油耗并抑制炭烟排放，研究了EGR对油耗与炭烟的影响。在1000 r/min ，pme ＝1．32 M Pa这一低速大负荷工况下，试验结果表明，LIVC结合EGR技术显著抑制了爆震，降低油耗8．6％，同时能够有效缓解LIVC带来的高炭烟问题。%For the fuel economy limited by downsizing the boost and direct injection gasoline engine ,the late intake valve clos-ing (LIVC) strategy was applied .The strategy suppressed the knock and improved the fuel economy effectively ,but led to the high soot emission of direct injection gasoline engine with high compression ratio .The influences of EGR on fuel consumption and soot were further analyzed .At 1 000 r/min and 1 .32 MPa pme ,LIVC together with EGR suppressed the knock dramatical-ly ,reduced the fuel consumption by 8 .6% and alleviated the high soot caused by the LIVC .