国Ⅴ阶段天然气发动机车载诊断系统的设计

OBD System Design of Stage Ⅴ CNG Engine

基于法规HJ 437—2008,总结了国Ⅴ阶段对CNG发动机车载诊断(OBD)系统的主要功能要求;对CNG发动机OBD系统关键诊断策略中关于催化器效率降低、氧传感器、缸内失火诊断策略进行了研究;同时,在添蓝控制器的基础上,针对CNG发动机的诊断策略和需求信号,对OBD系统进行硬件改进和软件设计;基于通用标准诊断仪ELM—327,进行了相关OBD功能验证试验。试验表明,系统设计基本满足OBD系统功能要求。

Based on HJ 437—2008 legislation,the main function requirement of stage Ⅴ for CNG engine OBD system were analyzed.The diagnosis strategies of catalyst performance,oxygen sensor and in-cylinder misfire in key diagnosis strategies of CNG engine OBD system were researched.For the diagnosis strategy and demand signal of CNG engine,the hardware modification and software design were carried out based on the Adblue controller.Based on ELM—327 diagnosis equipment,the verification experiments of OBD function were carried out.The result shows that the design of system can meet the requirement of OBD function.