改变缸内涡流降低车用柴油机NOx和微粒排放

Reducing NOx and Particulate Emissions of an Automotive DI Diesel Engine by Means of Changing Swirl Level inthe Cylinder

用喷气式可变涡流进气系统改变车用柴油机气缸内的涡流水平,研究了涡流对柴油机微粒(PT)和NOx排放的影响。结果表明,适度降低低速小负荷工况的涡流水平,在对PT排放影响不大的情况下,可以有效降低NOx的排放量;低速大负荷工况,适度提高气缸内的涡流水平,在不至于过大提高NOx排放的情况下,可以有效降低PT排放量。中速工况涡流水平的变化对PT排放量影响不大,而降低中速小负荷工况气缸内的涡流水平,可以有效降低NOx的排放量。降低高速工况气缸内的涡流水平,可以同时降低PT和NOx的排放量。

The effect of swirl level in the cylinder on participate and NOx emissions of an automotive DI diesel engine was experimentally studied using an air injection variable swirl intake system to change swirl level in the cylinder. Test result showed that in the case of lower rpm and lighter load, NOx emission decreased and participate emission was not significantly deteriorated when swirl strength was decreased to some extent. In the case of lower rpm and heavier load the effective method to decrease participate emission is to increase swirl level moderately. At medium rpm, the effect of swirl strength on participate emission is not significant, but in order to decrease NOx emission at lighter load, the swirl level should decrease to some extent. While at higher speed, the decrease of swirl level leads to the decrease of both participate and NOx emissions.