基于轻型汽油车的燃油蒸发控制系统泄漏测试研究

Study on Leakage Test of Fuel Evaporation Control System Based on Light-duty Gasoline Vehicle

在某特大城市机动车检验站筛选了123台轻型汽油车,依据《汽油车污染物排放限值及测量方法(双怠速法及简易工况法)》(GB 18285—2018)开展燃油蒸发控制系统泄漏测试,定量研究典型车型的燃油蒸发系统的现状及泄漏原因。结果表明,由于燃油系统硬管连接或碳罐遮挡造成无法进行后续泄漏测试的车辆约占14%;油箱盖加压测试合格率为95%;不合格车辆主要为10 a以上老旧车辆,合格车辆中加压损失与年均行驶里程(VKT)呈正相关,VKT每增加1000 km,油箱盖压力损失约为9.9 Pa;加油口加压测试显示,各排放阶段(除国六外)的合格率为44%~75%。

123 light-duty gasoline vehicles were selected at a motor vehicle inspection station in a mega-city,the leakage test of fuel evaporation control system was carried out for quantitatively studying the current situation and leakage causes of fuel evaporation system of typical vehicle model,according to"Limits and measurement methods for emissions from gasoline vehicles under two-speed idle conditions and short driving mode conditions"(GB 18285—2018).The results showed that about 14% of tested vehicles were unable to undergo subsequent leakage test due to hard pipe connection or carbon canister blocking of the fuel system.The qualified rate of pressure test of fuel tank cap was 95%.Unqualified vehicles were mainly older than 10 years.The pressure loss of qualified vehicles were positively correlated with their average annual mileage(VKT).The pressure loss of fuel tank cap was about 9.9 Pa for every 1000 km increase of VKT.The pressure test of the oil filler showed that the qualified rate of each emission section(except ChinaⅥ)was between 44%and 75%.