摘要
汽油机的小型化技术虽然在一定程度上能提高燃油经济性,但是也会带来爆震趋势加强的问题;鉴于EGR能够有效降低燃烧温度从而抑制爆震,在一台1.5 L缸内直喷汽油机上,开展了外部冷EGR对发动机燃油经济性影响的试验。结果表明,在2 000 r/min、负荷为1.4 MPa,引入EGR后,燃烧相位大幅改善,排气温度不断降低,燃油经济性得到改善,EGR为20%时的节油率最大,为7.9%;在2 000 r/min、负荷为0.8 MPa,引入EGR还能够降低泵气损失;在2 500 r/min外特性,引入EGR能够通过减少加浓程度改善燃油经济性;EGR也存在缺点:随着EGR率的升高,低速转矩会受到限制,循环波动率会不断加大,燃烧持续期会不断延长。
The Downsizing of gasoline engine can improve the fuel economy, but also intensify the knock tendency of the engine. Because of that the EGR（Exhaust Gas Recirculation） can weaken the intensify the knock through reducing the combustion temperature, the effect of the external cooled EGR on the fuel economy was studied on a 1.5L GDI（Gasoline Direct Injection） engine. The results show that on a speed of 2000r/min under the load of 1.4Mpa, EGR helps to improve the angle of combustion and reduce the exhaust gas temperature, and the fuel consumption is mostly reduced by 7.9% when the rate of EGR is 20%; on a speed of 2000r/min under the load of 0.8Mpa, EGR helps to reduce the loss of pumping; on a speed of2500r/min under the load of maximum, EGR helps to reduce the consistence of mixture. But the disadvantage of the EGR is that it will limit the low-speed torque, raise the COV（Coefficient of Variation）and extend the combustion duration.
出处
《小型内燃机与车辆技术》
2017年第4期19-25,共7页
Small Internal Combustion Engine and Vehicle Technique
基金
广东省科技厅省部产学研结合基金(2013B090400002)资助
关键词
汽油机
废气再循环
燃油经济性
Gasoline engine
Exhaust gas recirculation
Fuel economy
