排气背压对船用高速发动机性能的影响及优化研究

Study on the Effects and Optimization of Exhaust Back Pressure on the Performance of a High-Speed Marine Engine

为了改善某型船用高速发动机在高排气背压下的性能,在GT-Power软件中建立了船用高速发动机的一维工作过程仿真模型,并试验验证了模型精度。针对高排气背压下船用高速发动机性能急剧下降的问题,重新匹配了小流通截面积的涡轮增压器,并采用粒子群优化算法对其配气系统和喷油系统的关键参数进行了优化。结果表明:排气背压对船用高速发动机性能影响显著,排气背压的升高导致发动机燃油消耗率上升及功率大幅下降;优化后的配气和喷油系统大幅提升了发动机在高背压下的性能,在170 kPa排气背压下的涡轮前排气温度较优化前降低99.3℃,功率较优化前提升9.9%,残余废气系数较优化前下降5.8%,改善了增加排气背压给发动机带来的动力性下降及热负荷等问题。

A one-dimensional simulation model of a high-speed marine engine was established and validated in GT-Power software to improve the performance of a high-speed marine engine under high exhaust back pressure conditions.To solve the problem that the performance of the high-speed marine engine drops drastically under the condition of high exhaust back pressure,a small-flow turbocharger was matched and the key parameters of the intake system and the fuel injection system were optimized by using the particle swarm optimization algorithm.Results indicated that the increase of the exhaust back pressure had a significant effect on the engine performance,which led to the increase in fuel consumption rate and the drastical decrease in engine power.The optimized intake system and fuel injection system significantly improved the engine performance under high exhaust back pressures.Under the exhaust back pressure of 170 kPa,the engine exhaust temperature in front of the exhaust turbine was reduced by 99.3℃.Meanwhile,the power increased by 9.9%and the residual exhaust coefficient decreased by 5.8%.Thus,the decrease of power performance and thermal load caused by the increase of exhaust back pressure was significantly alleviated.