张光攀,陆海峰,李超,晁岳栋,李理光.进气VVT对低压EGR汽油机油耗影响研究[J].内燃机工程,2017,38(5):104-107.
进气VVT对低压EGR汽油机油耗影响研究
Effects of Intake VVT on Fuel Consumption of a Gasoline Engine with Low Pressure EGR
DOI：
关键词:进气VVT  废气再循环  燃烧  PFI汽油机
Key Words:intake VVT  EGR  combustion  port fuel injection gasoline
基金项目:国家自然科学基金项目（51376139）；同济大学KSPG教席基金项目；吉利-同济汽车研究院项目 National Natural Science Foundation of China (51376139)；KSPG Professorship Chair in CDHK Tongji University；Tongji Geely Automotive Institute
作者单位
张光攀,陆海峰,李超,晁岳栋,李理光 1.同济大学 汽车学院,上海 201804
2.同济大学 中德学院,上海 200092 
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摘要:基于一台带有低压废气再循环（EGR）回路的小排量增压进气道喷射（PFI）发动机,研究了进气正时(VVT)对低压EGR汽油机油耗与燃烧特性的影响。结果表明：EGR率越小，泵气损失越大,EGR率较小时泵气损失随EGR率的变化程度较小,EGR率较大时泵气损失随EGR率变化程度较大;进气门开启时刻相对于上止点提前或滞后均会使泵气损失减小。在1850 r/min、0.45 MPa工况下,进气门在上止点前10°、28°曲轴转角和上止点后24°曲轴转角开启可使泵气损失依次减小2.3%、11.9%和18.8%;进气门开启时刻越提前或迟后，EGR率越大,对应的燃烧持续期和滞燃期越大,燃油消耗率越小;与原机相比(燃油消耗率为294.49 g/(kW•h)),综合优化EGR率和进气门开启时刻后(EGR率为10%、进气门开启时刻为上止点后25°曲轴转角)的最佳燃油消耗率为283.44 g/(kW•h),可使燃油消耗率提高3.8%。
Abstract:The effects of intake VVT on the BSFC and combustion characteristics of a gasoline engine with low pressure EGR were studied based on a port fuel injection gasoline engine of small displacement with a low pressure EGR system. Results show that the smaller the EGR rate, the greater the pump loss, and when the EGR rate is small, the variation of the pump loss with EGR rate is also small, and vice versa; besides, the pump loss decreases when the intake valve open time is advanced or retarded. At 1850 r/min and 0.45 MPa, when the intake valve open timing is set at 10° and 28° before TDC, as well as 24° after TDC, the pump loss decreases by 2.3%, 11.9% and 18.8% respectively; when the open timing is advanced to before TDC or lagged behind after TDC with higher EGR, the combustion duration and ignition delay increases and the BSFC decreases. The lowest BSFC is 283.44 g/(kW•h) achieved by the optimization of the EGR rate and intake valve open timing, and it decreases by 3.8% compared with the original one of 294.49 g/(kW•h).
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