带汽油机颗粒捕集器的后处理系统台架快速老化研究

Study on Accelerated Aging of Exhaust Aftertreatment System with Gasoline Particulate Filter by Engine Bench

基于某1.5 L增压直喷发动机及搭载相应机型的整车,开展了带汽油机颗粒过滤器(gasoline particulate filter,GPF)的后处理系统台架快速老化试验研究。将两套相同的后处理系统样件在发动机台架上基于标准台架循环(standard bench cycle,SBC)分别进行等效整车20万km耐久里程的快速老化。其中一组试验中只考虑热老化,老化过程中燃油为正常状态;另一组试验中将热老化与机油灰分影响进行了耦合,老化过程中将整车20万km消耗同等量的机油加入到燃油中进行掺烧。分别测量了两组样件在老化过程中的灰分累积量、GPF压差、催化剂性能、整车排放等。结果表明:两组试验中,等效20万km耐久里程老化后,两套GPF灰分累积量分别为12.1 g和38.9 g,灰分主要集中在GPF载体底部中间区域;GPF压差在前2万km~5万km上升较快,随后平稳上升;掺烧机油老化会加速前级三效催化转化器(three ways catalyst,TWC)催化剂性能劣化,对后级GPF催化剂性能影响不明显;掺烧机油进行老化后样件的排放劣化程度相对较大;两组台架老化后样件分别搭载整车进行世界轻型车统一测试循环(worldwide harmonized light vehicle test cycle,WLTC)排放测试,结果都要差于实车耐久的排放结果,其中总碳氢(total hydrogen carbon,THC)和CO排放结果差异较小,NO_(x)排放结果差异较大;掺烧机油进行老化的GPF在很短等效里程中就能获得很高的颗粒物捕集效率。

An accelerated aging experiment of aftertreatment system(ATS)with gasoline particulate filter(GPF)was studied on a 1.5 L turbocharge gasoline direct inject(TGDI)engine and a relevant vehicle.Two sets of same ATS were aged on the engine bench based on standard bench cycle(SBC),the aging time was same as 200000 km durability on the vehicle.One set only suffered with high temperature while the normal fuel was used for this test.The other one set suffered with high temperature and ash at the same time,fuel blended with lube oil was used for this test,and the lube oil amount equaled to consumption after 200000 km usage.The ash weight,GPF backpressure,catalyst performance and worldwide harmonized light vehicles test cycle(WLTC)emission were reviewed during the aging process.The results show that,after the aging test the ash is mainly stored in the central area at the bottom of GPF,with a total weight 12.1 g and 38.9 g respectively.The backpressure of GPF increase sharply in the first 20000~50000 km and then increase steadily.The aging process used fuel blended with lube oil has a certain acceleration effect on the performance degradation of the three ways catalyst(TWC),but has no obvious effect on the performance of the GPF.The WLTC emission test results are deteriorated more serious with the second kind of accelerated aging ATS,but WLTC test results with both ATS are worse than the durability vehicle's,the difference between THC/CO results are small,while obvious between NO_(x) results.The GPF can be a high filtration efficiency state in a short equivalent mileage when aging use fuel blended with lube oil.