基于面径比的车用高速柴油机增压匹配研究

涡轮的面径比是废气涡轮增压器与车用发动机匹配的重要参数之一。将两台面径比不同的涡轮增压器与车用高速柴油机进行了匹配研究。结果表明:匹配较小面径比增压器的柴油机进气压力较高,新鲜充量增加,排气背压较高;低转速区域内进气压力和新鲜充量的增加提高了柴油机的燃烧效率,而排气负功的影响作用较弱,因此外特性输出转矩增加,燃油消耗率降低;高转速区域的排气负功影响作用增加,经济性变差;全工况烟度排放均较低。

Matching of Vehicle High Speed Diesel Engine and Turbocharger Based on A/R

Ratio of the area of minimum section of turbo entrance to the distance between the centroid of the area and the turbo rotation centre, denoted by A/R, is one of the key parameters to turbocharger matching. The present paper tested the performance of the vehicle high speed diesel engine as it equipped different A/R turbocharger. The results show that as the engine equipped small A/R turbocharger, in cylinder pressure, exhaust back pressure and volumetric efficiency were increased. The maximum increment of torque output up to 14%, the brake specific fuel consumption (BSFC) decreased 11% and the minimum BSFC of external characteristic decreased 3.5% in medium and low speed operating points. Contrast to low speed operating points, the loss of exhaust power increased in high speed operating points, so the BSFC increased. The smoke emission is always lower as the engine equipped small A/R turbocharger, because of the high volumetric efficiency and high in cylinder pressure.