董秀云^1,2，张涛^1,2，刘刚^1,2，高翠^1,2，杨扬^1,2，杨秀花^1,2

1.内燃机可靠性国家重点实验室，山东 潍坊 261061; 2.潍柴动力股份有限公司，山东 潍坊 261061

摘要：通过车载诊断（on board diagnostics, OBD）系统循环试验，分析商用车OBD系统的影响因素。研究表明:排气温度和废气流量是影响OBD系统故障诊断的关键因素，两者之间存在最佳匹配区间；整车载质量和排气管长度是影响排气温度的主要因素，排气温度与整车载质量正相关，与排气管长度、整车综合速比负相关；整车综合速比是影响废气流量的主要因素，废气流量与整车综合速比正相关。试验结论可以为商用车设计提供参考。

关键词：商用车；OBD；载质量；综合速比；排气管长度

Abstract：According to the on board diagnostics (OBD) system cycle test, the factors of effect commercial vehicle OBD system are analyzed. The results show that the exhaust temperature and exhaust gas flow rate are the key factors affecting the OBD system, and there is an optimal matching between them. The vehicle mass and exhaust pipe length are the key factors affecting the exhaust temperature.It is positively related to the vehicle mass,negatively related to the length of the exhaust pipe and the overall speed ratio of the vehicle.The overall speed ratio of the vehicle is the key factor affecting the exhaust gas flow rate,it is positively related to the overall speed ratio of the vehicle.The test results can provide reference for commercial vehicle design.

Keywords:commercial vehicle; OBD; vehicle mass; vehicle speed ratio; exhaust pipe length