汽油车燃油蒸发控制系统泄露车载诊断及试验

Gasoline Vehicle's OBD on EVAP System Leak Detection and Demonstration Test

我国将出台的6阶段轻型车排放法规里新增了汽油车燃油蒸发控制(EVAP)系统泄露车载诊断(OBD)要求。这些规定多年前即已在美国OBDII法规里强制执行,催生出了多种实现EVAP系统泄露OBD的策略及配套组件。从不同的视角出发可以对它们进行不同的分类。建立了一套多层级分支分类方式,全面归纳和辨析了各类监测策略,可供国内制造商借鉴选用。对EVAP系统泄露车载诊断的演示试验监测流程进行介绍,便于制造商参考配合。开发并实车运用了防范失效措施(defeat device)的装置,该装置的微压仪实时记录压力信号,信号的幅度和动态过程特征鲜明可辨。该信号验证了车辆OBD系统的运行是否与已申报的诊断逻辑相一致。

Gasoline Vehicle＇s OBD on EVAP System Leak Detection will be introduced into China＇s6thstage emission standard for LDVs. Such requirements had already been in force in California OBDⅡ for years,and manufactures have developed many kinds of strategies for their vehicles sold in US. A category that classify all these strategies will be helpful for the local manufactures to make their own choice to accomplish the task. The demonstration requirement and the test procedure were alsoillustrated in this article,as a guide for the certifications. To prevent defeat devices,a pressure /vacuum record facility was built up and was run in the demonstration tests for certain vehicles,and the device of micro pressure meter can record pressure signal in real time and the signal amplitude characteristic and dynamic process were shown obviously. The signal verified that whether the vehicle OBD system running is consistent with the declared diagnosis logic.