电增压协同EGR技术对发动机排放性能的影响

Effect of Electric Supercharging Combined with EGR Technology on Engine Emission Performance

在一台带废气涡轮增压器的直喷汽油机进气道上空气滤清器后串联电动涡轮增压器,通过控制燃烧循环变动系数,探索废气再循环率(REGR)的使用极限,进而研究电增压对汽油机排放性能的影响。结果表明:电动增压器能够弥补废气涡轮增压器的不足,可获得较大的REGR;在外特性和部分负荷下,电动增压器促进废气涡轮增压器提升REGR,使得不同转速和不同负荷下的NO_(x)排放量(φ_(NO_(x)))整体下降、HC排放量(φ_(HC))整体上升;各试验工况下,φ_(NO_(x))下降4 g/(kW·h)以上,φ_(HC)上升基本保持在3 g/(kW·h)以内;合理应用电增压获得最高REGR在提升发动机动力性的同时能够较好地控制其排放性。

The electric turbocharger is connected in series to the air filter on the intake port of a direct injection gasoline engine with an exhaust turbocharger.By controlling the coefficient of variation of the combustion cycle,the limit of the use of the exhaust gas recirculation rate(REGR)is explored,and then the impact of electric turbocharging on the exhaust performance of the gasoline engine is studied.The results show that the electric supercharger can make up for the inadequacy of the exhaust turbocharger,and can obtain a larger REGR;Under external characteristics and partial load,the electric supercharger promotes the exhaust gas turbocharger to increase REGR,which makes the NO_(x)emissions at different speeds and loads(φ_(HC))overall decrease,HC emissions(φ_(HC))overall rise;Under each test condition,φ_(NO_(x))decreases by more than 4 g/(kW·h),φHCrise is basically kept within 3 g/(kW·h);Reasonable application of electric supercharging to obtain the highest REGRcan improve the engine power performance and control its emissions.