Influence of the Different Fuel Spray Wall Impingement Angles on Smoke Emission in a DI-Diesel Engine

Reduction of smoke emission from diesel engines is important in order to meet upcoming stringent exhaust gas regulations and also for improving fuel economy. In this paper, the reduction of smoke from DI diesel engines for heavy duty vehicles is discussed. A single cylinder engine test and three dimensional numerical analysis were carried out in order to obtain necessary and useful information for designing a combustion chamber and a fuel injection nozzle that could realize reduced smoke emission. This study is focused particularly on the behavior of the fuel spray which impinges on the piston cavity wall in the case of a reentrant type combustion bowl. As a result, it was found that the spray wall-impingement angle performs an important role in promoting fuel-air mixing. It is thus an important parameter which controls the main combustion region. It was also found that the optimized spray wall-impingement angle contributes to the efficient utilization of the air trapped in the cylinder, leading to a reduction in smoke emission.