배기가스 재순환과 다공분사가 소형 직분식 디젤엔진의 연소와 배기에 미치는 영향

Abstract

EGR is a well known technique to reduce nitrogen oxides (NOx) emission in a diesel engine but it increases particulate matter (PM). As a solution, multi-hole injector could be applied. Multi-hole injector could lead faster atomization and vaporization due to the reduced hole-diameter. It promotes the engine performance and increases the premixed combustion portion that results low PM emission. On the other hand, NOx emission increases by the increase of the combustion temperature with enhancement of the air-fuel mixing. To resolve this problem, the effects of EGR and multi-hole injection on combustion and exhaust emissions were studied. The experiment was carried out in a single-cylinder optical direct-injection diesel engine equipped with a high-pressure common rail fuel injection system. The experimental results showed that the multi-hole injector reduced ignition delay and increased the portion of the premixed combustion. EGR affected the autoignition and combustion processes. As a result NOx emission was significantly reduced while total hydrocarbon(THC) and CO emissions were increased.