混合动力控制策略对催化转化率影响的研究

在NEDC循环工况下,研究了采用400目催化转化器的混合动力汽车的动力控制策略对其催化转化器的转化效率的影响。研究表明,怠速停机后,残余排放物附着在气缸及排气管内,在发动机重新启动后,会造成催化转化器过载,从而使转化率下降;在加速断油过程中,由于没有燃油喷射,新鲜空气被直接排入排气管,造成排气管内氧浓度的增加,从而影响NOx的转化。更换600目催化转化器后,催化转化率有明显改善,但仍不能根除控制策略对转化率的影响。

A Study on the Influence of Powertrain Control Strategy in HEV on Catalytic Conversion Rate

The effects of powertrain control strategy of a hybrid electric vehicle(HEV) with a catalytic converter of 400csi honeycomb substrate on its catalytic conversion efficiency on the new European driving cycle(NEDC) are analyzed.The results show that catalytic conversion rate will drop when restarting the engine since the residual pollutants remained in cylinder and exhaust pipe during the idle stop period cause the overloading of catalytic converter;while in the course of deceleration fuel cut off(DFCO),the fresh air is expelled straight into exhaust pipe and enrich its oxygen concentration,affecting the catalytic conversion of NOx.Though the catalytic conversion rate can be improved markedly when using 600csi honeycomb substrate in catalytic converter,the effects of control strategy in HEV on catalytic conversion rate can not be eradicated.