装配SCR系统的混合动力公交车排放特征研究

Study on the Emission Properties of Hybrid Electrical Transit Bus with SCR System

利用车载测试系统,对两种类型的混合动力公交车进行了整车排放测试,研究了装备SCR系统的国Ⅳ混合动力公交车排放情况,结果表明,SCR技术的应用能一定程度上降低NOx排放量,但同时SCR技术在混合动力公交车上实际应用时存在排气温度过低、从而导致NOx转化率偏低的问题。建议采用某种技术(如排气加热系统)提高城市公交车排气温度或提高SCR的低温性能,以便提高NOx转化效率。

The vehicle emission test on two different types of hybrid electrical transit buses（HEB）was conducted,using on-board test system.Emission of State Ⅳ HEB with SCR was studied.The result showed that the use of SCR technology could reduce NOx emissions to a certain extent.However,SCR technology application in HEB also faces with low NOx conversion efficiency caused low exhaust temperature.It was suggested that some technology should be adopted to raise HEB exhaust temperature（for example the exhaust heating system） or improve the low temperature performance of SCR in order to improve the NOx conversion efficiency.