Abstract: Exhaust system is an important part of engine accessories, the size of exhaust backpressure directly affects the pump gas loss and thermal efficiency of diesel engine, thus affecting the vehicle fuel economy performance. In this paper, the variation trend of engine power and fuel consumption rate with the increase of exhaust backpressure was measured under rated working conditions through diesel engine bench test. The simulation model of truck was built in AVL CRUISE software, through the influence curve of exhaust backpressure on vehicle economy, the optimization direction of exhaust system is given.

Key words: Exhaust system; Exhaust backpressure; The diesel engine; Fuel economy; Bench test

摘要： 排气系统作为发动机附件的重要组成部分，排气背压的大小直接影响到柴油发动机的 泵气损失和热效率，从而影响整车燃油经济性的表现。论文通过柴油机台架试验，在额定工 况下测得发动机功率和燃油消耗率随排气背压的变化曲线，利用 CRUISE 软件进行整车经济 性仿真，通过排气背压对整车燃油经济性的影响，给出排气系统优化方向。

关键词: 排气系统；排气背压；柴油机；燃油经济性；台架试验