小型点燃式发动机应用LPG的微粒排放特性

Characteristics of Particulate Emissions from a Small SI Engine with LPG Fuel

介绍了液化石油气(LPG)在点燃式发动机上应用时微粒排放特性的试验研究.试验在一台四行程、水冷125mL单缸电喷式发动机上进行.结果表明,LPG在点燃式发动机上应用时也有大量的微粒排放,但其排放的总颗粒数与使用汽油燃料时基本相同.LPG燃料排放的微粒在粒度分布上有双峰分布的特点,但有时第1个峰的特征不明显,第2个峰对应的粒径大小同汽油机基本相同,发动机中等负荷时的微粒排放量最大,浓混合气的微粒排放量高,微粒的粒数浓度在中等转速时最大.

This paper presents the experimental studies of particulate emissions from a small SI engine with LPG fuel. Experiments were carried out on a four-stroke water-cooled 125 mL single cylinder EFI engine. Test results show that: there are a great quantity of particulate emissions from the LPG fueled engine, but it has the same total number of particulate emissions as that given from a gasoline fueled engine, and the distribution of the particulate number has two peak values. The first one is not evident, but the second one occurs in about the same position of that of the gasoline fueled engine. At medium loads, the LPG fueled engine emits the highest quantities of exhaust particulates. A richer mixture will lead to higher particulate emissions, too. The particulate emission is high at a medium engine speed.