汽油机两级增压系统的匹配与性能研究

A Study on Two-Stage Charging System Matching and Performances of Gasoline Engines

在某单级涡轮增压汽油机的基础上,围绕提升低速扭矩及改善涡轮迟滞效应进行了复合增压系统、两级涡轮增压系统匹配方法研究。采用GT-Power软件建立某汽油机单级涡轮增压与两级增压发动机(复合增压发动机和两级涡轮增压发动机)仿真模型,并借助实测结果进行校核。在此基础上,利用模拟计算结果对单级涡轮增压和两级增压系统的低速扭矩特性、动态响应特性和燃油经济性进行比较分析。研究结果表明:复合增压与两级涡轮增压发动机的低速扭矩特性比单级涡轮增压发动机分别增加了62.80%和54.35%,燃油经济性分别减少了23.45%和22.71%;动态响应特性由优到劣依次为复合增压、两级涡轮增压、单级涡轮增压发动机,并且在1 500r/min(低速区域)三者动态响应特性差距最为明显。

On the basis of single-stage turbocharged gasoline engine a new matching method of engine/ charging system for two-stage sequentially turbocharged system and superturbo system was put forward to improve the low speed torque and turbo lag effect. The GT-Power models were set up for each of the charging systems and calibrated by the experimental results. Based on the GT-Power simulation results, the low speed torque and transient load response characteristics as well as the fuel economy of these three types of charging systems under consideration were compared and analyzed with each other. Results indicate that the low speed torgue of the superturbo and the two-stage sequential turbocharger could be increased by 62.80% and 54.35% respectively, while the engine BSFC at full load could also be reduced by as much as 23.45% and 22. 71% respectively as compared to the single-stage turbocharged baseline engine. For the transient load response characteristics, the charging systems ranked in the order of priority are the superturbo, the two-stage sequential turbo and the single-stage turbo. These three types of charging systems had quite different transient load response characteristics at 1 500 r/min.