Abstract: Based on in vehicle emission testing portable emission measurement system (PEMS), a simulated emission test is conducted on sensors and deteriorated components of a National VI heavyduty diesel vehicle in use. The test results show that the failure of the upstream temperature sensor and selective catalytic reduction (SCR) temperature sensor, as well as the deterioration of exhaust gas re-circulation (EGR) and inter cooler, can significantly worsen the vehicle's nitrogen and oxygen emissions, exceeding the standard emission limit. The failure of the diesel particulate filter (DPF) upstream temperature sensor can cause the nitrogen and oxygen emissions to exceed the limit, but the impact is relatively small. However, the failure of the downstream temperature sensor of nitrogen and oxygen will not cause the vehicle's emissions to exceed the limit. At the same time, the on-board diagnostics (OBD) system can effectively identify vehicle faults and give an alarm.

Key words: fault simulation; OBD detection; on board emission testing; heavy duty aftertreatment

摘要： 为研究车辆后处理故障对车辆排放的影响，基于便携式排放测试系统（PEMS）对一辆 在用国六重型柴油车进行传感器和劣化件故障模拟排放测试。测试结果表明，氮氧上游温度 传感器和选择性催化还原（SCR）上游温度传感器故障及废气再循环（EGR）劣化和中冷器 故障会导致车辆氮氧排放明显恶化，氮氧排放超标准排放限值，柴油机颗粒捕集器（DPF） 上游温度传感器故障会导致氮氧排放超限值，但影响较小，而氮氧下游温度传感器故障则不 会导致车辆排放超限值，同时车载诊断（OBD）系统能有效识别车辆故障并报警。

关键词: 故障模拟；OBD 检测；车载排放测试；重型车后处理