进气充量温度对汽油机性能影响程度的研究

Resesrch of Inlet Charge Temperature on Performances of Gasoline Engines

通过发动机台架,分别对一台自然吸气进气道喷射(NA-PFI)汽油机和一台涡轮增压缸内直接喷射(TGDI)汽油机进行了外特性试验,研究进气充量温度对不同类型汽油机动力性和经济性的影响。试验结果表明:增加进气充量温度,NA-PFI汽油机的动力性下降。当进气充量温度由25℃增加到60℃时,在汽油机转速高于4 000 r/min区域,外特性平均有效压力的降低幅度达到10%。适当提高进气充量温度会提高NA-PFI汽油机的经济性,但进气充量温度过高会导致NA-PFI汽油机的经济性恶化。对于TGDI汽油机,增压能够补偿由于进气充量温度增加所引起的进气量损失,导致进气充量温度对TGDI汽油机动力性和经济性的影响均不是很明显。

Full load performance tests were conducted on engine test bench for a natural aspiration gaso- line engine with port fuel injection （NA-PFI）and a gasoline direct injection engine with turbocharger （TGDI） to investigate the effects of inlet charge temperature on power performance, fuel economy and emission properties of gasoline engines. Results show that increasing the inlet charge temperature weakens the power performance of NA-PFI engine. When increasing the inlet charge temperature h＇om 25 -C to 60 -C, the brake mean effective power （BMEP） will be reduced by 10% at the engine speed of above 4000 r/ min. Appropriately increasing the inlet charge temperature improves the fuel economy of NA-PFI engine, whereas too much increase in the inlet charge temperature deteriorates the fuel economy. For TGDI en- gine, however, the effects of after-intercooler inlet charge temperature on power performance and fuel consumption are insignificant because the turbocharger can compensate the inlet charge loss from the in- creasing charge temperature.