Effects of the swirl ratio and injector hole number on the combustion and emission characteristics of a light duty diesel engine

Abstract

In this study, the effects of swirl and the injector hole number were investigated to enhance the mixing of fuel and air. Both experimental and analytical methods were employed. The KIVA code coupled with the CHEMKIN chemistry solver was used to analyze the swirl intensity at various angles of the swirl control valve and experimental results. For the experimental investigation, a 498.75 cc single cylinder engine and a 55 kW AC dynamometer were employed. The experiments were conducted at IMEP values of 6 and 10 bar with 7, 8, 9, and 10 hole injectors. The swirl intensity was varied by opening of the swirl control valve from 0 degrees to 90 degrees. The experimental results demonstrated that the swirl intensity has an effect on the combustion and emission characteristics. An enhanced swirl intensity reduced the PM and CO emissions but increased the NOx emissions and ISFC. An increase of the injector hole number resulted in decreases of the PM and CO emissions along with a an increase of NOx emissions and no significant difference of output. However, the exhaust characteristics with the 10 hole injector deteriorated as the interference increased.