低负荷下车用重型柴油机排放与热效率的规律研究

摘要

为了实现重型柴油发动机在低负荷下的超低排放及高的有效热效率，在1台配备了两级涡轮增压系统的重型柴油发动机上研究了在低负荷下采用低温燃烧策略时不同EGR率对发动机排放以及热效率的影响及不同转速下发动机热效率的变化规律。研究结果表明，EGR率的增加有利于改善排放和提高热效率，但随着发动机转速的增加，热效率呈下降趋势。%In order to achieve the ultra-low emission and high thermal efficiency of heavy duty diesel engine ,the influences of different EGR rates on engine emission and thermal efficiency under low temperature combustion strategy at low load and their influences on thermal efficiency under different speeds were researched on a heavy duty diesel engine with two-staged turbo-charged system .The result shows that the increase of EGR rate helps to improve the exhaust emission and thermal efficiency , but the thermal efficiency decreases with the increase of engine speed .