可变压缩比对增压中冷柴油机性能影响的模拟分析

摘要

为计算可变压缩比技术对柴油机燃油经济性和排放性能的影响,该文通过GT-Power软件,对一台装备有中冷废气再循环系统和可变几何涡轮增压系统的C6.6重型柴油机进行了建模和仿真分析,并采用了直喷燃烧预测模型对模型的有效性进行了验证.研究结果表明,可变压缩比技术使柴油机中、低负荷下燃油经济性的改善可达7.2％,再结合适当的废气再循环(exhaust gas recirculation,EGR)率和可变几何涡轮增压系统(variable geometry turbocharger,VGT)控制策略,柴油机的NOx和颗粒物的排放性能可达到欧洲5号标准瞬态测试循环(european transient cycle,ETC)中的排放要求.因此,可变压缩比技术可以有效改善直喷柴油机的燃油经济性,提高排放性能.%In order to investigate the effect of variable compression ratio (VCR) on fuel economy and emission reduction, a model of the heavy duty diesel engine C6.6 equipped with inter-cooling exhaust gas recirculation (EGR) and a variable geometry turbocharger (VGT) was presented and analyzed based on the GT-Power software and its validity was verified with a predictive direct-injection jet combustion model. The simulation results showed that the use of variable compression ratio improved fuel economy to 7.2% at low and medium load, also Nox and soot emissions could meet the need of Euro V values for ETC with corresponding EGR fraction and VGT strategy. Variable compression ratio can improve the fuel economy and emission performance of direct injection diesel engine effectively.