重型车国六法规和中国工况发动机测试循环的差异分析

Analysis of the Engine Test Cycles of China Ⅵ Heavy Duty Vehicle Standard and China Engine Test Cycle

选取一台满足国六排放标准的柴油发动机,开展基于国六法规发动机测试循环(WHSC和WHTC)以及中国工况发动机测试循环(CHSC和CHTC)的测试。结果表明:运行中国工况的发动机稳态和瞬态测试循环,转速、转矩和功率回归分析的结果均满足国六法规的要求。对于该发动机,稳态循环的NOx、PM和THC污染物,CHSC比WHSC分别高134.5%、29.6%和94.4%。而PN排放,CHSC比WHSC低65.6%。瞬态循环的NOx、PM和PN污染物,CHTC较WHTC分别增加了62.9%、96.4%和64.3%。CHTC前350s的排气温度更低,对低速低负荷下的后处理转化效率提出了更大的挑战。

This paper studies the engine test cycles including world harmonized steady cycle(WHSC),world harmonized transient cycle(WHTC),china heavy-duty steady cycle(CHSC)and china heavy-duty transient cycle(CHTC)based on a diesel engine which meets the China Ⅵ heavy duty vehicle emission standard.The results show that regression analysis results of speed,torque and power all meet the requirements of the China Ⅵ heavy duty vehicle standard.For this engine,NOx,PM and THC pollutants under CHSC are 134.5%,29.6% and 94.4% higher than those under WHSC,respectively.PN emissions of CHSC is 65.6% lower than that of WHSC.NOx,PM and PN pollutants under CHTC are 62.9%、96.4% and 64.3% higher than those under WHTC,respectively.The exhaust temperature of the first 350 seconds at CHTC is lower,which poses a greater challenge to the conversion efficiency of the after-treatment system at low speed and low load.