Effects of ethanol added fuel on exhaust emissions and combustion in a premixed charge compression ignition diesel engine

The use of Diesel engines for vehicle has been increasing recently due to its higher thermal efficiency and lower CO₂ emission level. However, in the case of Diesel engine, NO_x increases in a high temperature combustion region and particulate matter is generated in a fuel rich region. Therefore, the technique of premixed charge compression ignition is often studied to get the peak combustion temperature down and to make a better air-fuel mixing. However it also has got a limited operating range and lower engine power produced by the wall wetting and the difficulty of the ignition timing control. In this research, the effect of injection strategies on the injected fuel behavior, combustion, and emission characteristics in a premixed charge compression ignition engine were investigated to find out the optimal conditions for fuel injection, and then ethanol blended diesel fuel was used to control the ignition timing. As a result, the combustion pressures and rate of heat release of the blended fuel became lower, however, indicated mean effective pressure showed fewer differences. Especially in the case of triple injection, smoke could be reduced a little and NO_x emission decreased a lot by using the ethanol blended fuel simultaneously without much decreasing of indicated mean effective pressure compared to the result of 100% diesel fuel.