Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions from the diesel engines are recognized main cause which influenced environment strong. In this study, the potential of biodiesel fuel and oxygenated fuel (ethylene glycol mono-n-butyl ether; EGBE) was investigated as an effective method of decreasing the smoke emission. The smoke emission of blending fuel (EGBE 0~20 vol-%) was reduced in comparison with diesel fuel and it was reduced approximately 64% at 2000 rpm, full load in the 20% of blending rate. But torque and brake specific energy consumption (BSEC) didn't have no large differences. But, NOx emissions from biodiesel fuel and EGBE blended fuel were increased compared with diesel fuel.

일반적으로 선박용 디젤엔진의 아산화질소(N₂O)배출률은 이산화황(SO₂)배출률과 밀접한 상관성을 갖고 있고, 선박에서 사용되는 연료의 다양성은 N₂O배출특성에 영향을 미친다고 받아들여져 왔다. 최근의 연구보고에 의하면 연료 연소에서 발생한 충분한 일산화질소(NO)가 존재할 경우, 배기의 SO₂배출률이 N₂O생성에 미치는 영향은 NO의 영향보다 막대하게 크다. 그러므로 SO₂성분으로부터 기인하는 N₂O생성은 NOx저감을 위한 배기가스 재순환(EGR) 시스템에서 중요한 인자로 작용한다. 본 실험적인 연구의 목적은 SO₂유량 증가를 갖는 디젤엔진의 흡기가 배기의 N₂O배출률에 미치는 영향에 대하여 조사하는 것이다. 실험에 사용된 테스트 엔진은 2600rpm에서 12kW의 출력을 갖는 4행정 직접분사식 디젤엔진이고, 운전조건은 75% 부하에서 실시되었다. 0.499%(m3/m3)의 SO₂표준가스는 흡기의 SO₂농도를 변화시키기 위해 사용되었다. 결과적으로 황 성분을 포함하지 않는 연료는 SO₂를 배출시키지 않았고, 흡기 중에 SO₂표준가스의 증가에 따른 배기의 SO₂배출률은 SO₂흡입률과 비교하여 거의 같은 비율이었다. 또한, 흡기의 SO₂유량 상승은 N₂O배출률을 상승시켜 배기 중의 N₂O는 흡기의 SO₂혼합기에 의해 생성되었다. 결국 황 성분을 함유한 연료는 연소 중에 SO₂를 형성하고 배기 중의 N₂O는 연소실에 존재하는 NO와 SO₂의 반응에 의해 발생된다고 할 수 있다.

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions of diesel engines are recognized as main causes of the air pollution. DI diesel engine is widely used for the sake of minimization on exhaust emission. Because biodiesel fuel is a renewable and alternative fuel for diesel engine, its usability is expanded. The smoke emission of esterfied rapeseed oil is reduced remarkably in comparison with commercial gas oil, that is, it was reduced approximately 44.5% at 1500rpm. But, brake specific energy consumption showed very slight differences. It was concluded that esterfied rapeseed oil can utilize effectively as an alternative and renew-able fuel for diesel engine.

To investigate the relation of NOx emission and consumption rate in a direct injection diesel engine with a multihole nozzle under same fuel consumption and rpm, a naphthyl ethylenediaming method on NO, emission and Tektronix oscilloscop on the indicator diagrams have been used. Comparisons of the NOx emission and fuel consumption rate made on various conditions have led to the fllowing results. 1. The higher the injection pressure in the later injection time the lower NOx emission and the fuel consumption rate have been attained. 2. By the change of nozzle hole diameter under the same injection pressure, the NOx emission was much more lowered in the small diameter than large one, but fuel consumption rate was in inverse proption to the NOx emission. 3. The effect of injection spray angle, 1ndn on NOx emission, fuel consumption rate under same injection time and injection pressure was neglectable.