满足国六法规的汽油机颗粒捕集器故障诊断策略功能开发

Fault Diagnosis Strategy Function Development of Gasoline Particulate Filter in Compliance with China Ⅵ Regulation

基于压差—流量特性建立汽油机颗粒捕集器(gasoline particulate filter,GPF)压差模型,提出了以压差测量值—模型值为基础的GPF载体特征因子算法,该特征因子能够准确地表征测压管路连接状态与GPF载体状态;考虑到GPF本身的载体特点、压差传感器测量偏差及GPF出口弯管所带来的流阻,将GPF载体特征因子算法改进为压差梯度修正方式,并通过对全球轻型车测试循环(world-harmonized light-duty vehicle test cycle,WLTC)工况分析得到适宜条件下的诊断窗口。实车验证结果表明,WLTC工况下可以准确诊断GPF移除故障,车载诊断系统(on-board diagnostics system,OBD)GPF监控组在用实际监测频率(in-use performance ratio,IUPR)分子计数器成功增加,且对车辆道路试验结果进行的统计学分析表明诊断阈值的设置满足3σ标准,由此实现了诊断策略准确性与实时性兼顾的需求。

Based on the gasoline particulate filter(GPF) differential pressure model established by the differential pressure– flow characteristics,a GPF characteristic factor algorithm(FGC) based on the differential pressure measurement value – model value was proposed,which could accurately characterize the connection state of the pressure pipeline and the GPF carrier status.Taking into account the GPF carrier characteristics,the measurement deviation of the differential pressure sensors,and the flow resistance caused by the outlet elbow,the FGCalgorithm was improved to the differential pressure gradient correction method,and the appropriate diagnosis window was obtained through the analysis of the world-harmonized light-duty vehicle test cycle(WLTC).The actual vehicle verification results showed that the GPF removal failure in the WLTC cycle could be accurately diagnosed and the in-use performance ratio(IUPR) numerator for the GPF monitor group of the on-board diagnostics(OBD) system had successfully increased.The statistical analysis of the vehicle road test results showed that the diagnosis threshold met the 3σ standard,which achieved the balance requirement of diagnosis strategy between accuracy and real-time performance.