空燃比对直喷汽油机微粒排放特性的影响

Effect of Air-fuel Ratio on Particle Emission Performance of GDI Engine

以直喷汽油机为对象建立试验台架及试验测控系统,以研究空燃比对缸内燃烧和微粒排放粒度分布的影响规律。结果表明,在进气过程中喷油均质燃烧模式情况下,不同空燃比对应的微粒排放大部分在50nm以下;随着空燃比的增加,微粒粒径分布曲线形状由核模态、积聚模态双峰分布向核模态、初始颗粒的双峰分布渐变,最终变为核模态的单峰分布,且总微粒数量浓度降低。

Measurement and control system of gasoline direct injection engine （GDI engine） and the test rig are set up, to investigate the effect of air-fuel ratio on the in-cylinder combustion and particle size distribution characteristic. The result shows that under the homogeneous charge mode in the intake process, size of the most particulate matter diameter is under 50nm. With the increase of air-fuel ratio, the distribution curve shape of particle size changes from the bimodal distribution of nuclei mode and accumulation mode to the bimodal distribution of nuclei mode and initial particle, then it changes to the unimodal distribution of nuclei mode, the total particle number concentration is reduced in the process.