수소-DME 압축착화엔진에서의 DME 분사 시기에 따른 영향

Abstract

The hydrogen combustion with dimethyl-ether(DME) as an ignition promoter was investigated in a single cylinder engine using compression ignition engine. The hydrogen was injected at intake manifold to make homogeneous charge, and the DME was injected directly into the cylinder with common-rail system as an igniter. The hydrogen and DME injection quantity and DME injection timing were varied corresponding to the fixed total lower heating value. The injection timing of DME was varied from 35 crank angle degrees before the top dead center to the top dead center. indicated mean effective pressure, ignition delay, and emissions were tested under the same load condition. As DME injection timing was advanced, combustion temperature was lowered, and the emissions of carbon monoxide and hydrocarbon were increased by formation of lean premixed charge. When DME was injected near 10 crank angle degrees before top dead center, carbon monoxide and hydrocarbon emissions were minimum and the nitric oxides emission was maximum due to high pressure and heat release rate. If the injection timing of DME was retarded near to the top dead center, indicated mean effective pressure was increased due to partially rich region. DME early injection before the 40 crank angle degrees before the top dead center made unstable combustion due to excessive lean DME mixture. Misfire was occurred when DME was injected after the top dead center.