基于耐久老化车辆的实际道路行驶NOx排放控制方法研究

Research on NO_(x)Emission Control Method of Real Driving Based on Durable Aging Vehicle

为满足国六排放法规中在用车辆16万km RDE(real driving emission)检查要求,对两辆耐久老化车辆展开苛刻的1℃环境下转毂激进RDE试验研究。通过调整发动机的控制策略,对试验中NO_(x)排放偏高的两个极端工况:冷起动后急加速及热机起步急加速至超高速阶段的运行参数进行优化,然后在多种组合下的转毂循环及实际道路行驶排放中对优化前后的策略进行了对比验证。结果表明:VVT、过量扫气系数、目标空燃比及老化催化器窗口控制分别对耐久老化车辆的冷、热机超大负荷运行工况下NO_(x)排放量影响较大,合适的策略可使NO_(x)整体下降超40%;先基于耐久老化车辆开展转毂激进RDE开发,再进行实际道路行驶排放验证,是一种有效的RDE开发方法。

In order to meet the RDE(real driving emission)sampling requirements of 160,000 km in-use vehicles stipulated in China 6 emission regulations,the aggressive RDE test cycle on test bench is carried out on two durable aging vehicles under the critical environment of 1℃.By adjusting the engine control strategies,the operation parameters of two extreme working conditions with high NO_(x)emission are optimized:rapid acceleration after cold start and rapid acceleration to super high vehicle speed after hot start,then the comparative verification tests between the new and old strategies in variable emission combinations include roller cycles and RDE are carried out.The results show that the VVT,excess scavenging coefficient,lambda target value and aging catalyst window con⁃trol have great impact on NO_(x)emission of durable aging vehicle under cold and hot engine’s high load conditions.Appropriate control strategies can reduce the total NO_(x)emission by more than 40%.It is an effective RDE development method to firstly carry out the emission development based on durable aging vehicles under aggressive RDE cycle,and then validate it on the real road.