增压直喷汽油机冷起过程碳氢排放影响因素试验研究

Influencing Factors of HC Emission during Cold Start for Turbocharged GDI Engine

针对增压直喷汽油机的特点,进行了冷起动HC排放影响因素的探讨,研究过程采用试验与仿真相结合的方法,基于发动机试验台测试数据,重点分析了冷起动过程中空燃比、点火策略、缸内残余废气、喷油策略对HC排放的影响。分析结果表明:在发动机冷起动过程中,实现有效的稀燃和降低缸内残余废气有利于降低HC排放;适当的喷油策略可降低HC排放,但需要合理地组织发动机瞬态进气;发动机点火角提前有利于降低HC排放,但需要考虑整车三元催化器暖起过程。

For the characteristics of turbocharged GDI engine ,the influencing factors of HC emission during cold start was discussed through test and simulation .Based on the measured data from test bench ,the influences of air-fuel ratio ,ignition strategy ,in-cylinder residual gas and injection strategy on HC emission were mainly analyzed during cold start .The results showed that the effective lean burn and in-cylinder residual gas reduction during cold start were beneficial to the HC reduction . The appropriate fuel injection strategy could reduce HC emission ,but the reasonable adjustment of transient intake was neces-sary .The advance of ignition timing was also helpful to reduce HC emission ,but the warming-up of vehicle three way catalysts should be considered .