大型LPG公交车运行工况与排放特性的试验研究

An Experimental Study on the Operating Conditions and Emission Characteristics of Large-sized LPG Bus

采用车载排放测试技术,对大型LPG公交车辆运行工况和排放特性进行试验研究。结果表明,公交车运行工况与国家排放标准规定的重型车发动机台架测试工况ESC和ETC有较大的差异。试验公交车辆的平均运行车速为16.7km/h,怠速时间占总运行时间的26.6%,加减速时间占61.3%,加减速度主要集中在-0.5～0.5m/s2之间。发动机过量空气系数为1.06～1.5,CO、NOx和HC的平均排放速率分别为0.016、0.19和0.026g/s。排放速率随车辆加速度的增加而升高,HC的高排放速率区位于低速、高加速区,NOx的高排放速率区位于高速、高加速区。

An experimental study on the operating conditions and emission characteristics of large-sized LPG bus is conducted with on-board emission test technique.The results show that the operating conditions of large public bus is quite different to the driving cycles ESC and ETC for bench test of heavy-duty vehicle engine specified in national regulation.The average speed of bus is 16.7km/h,idle time accounts for 26.6% of total operating time while the times of acceleration and deceleration account for 61.3% with their value falls into the range of-0.5-0.5m/s2.The excess air coefficient of engine is 1.06~1.5,the average emission rate of CO,NOx and HC is 0.016,0.19 and 0.026g/s respectively,which increases with the rise in vehicle acceleration.The high HC emission region is located at low speed and high acceleration area,while that for NOx at high speed and high acceleration area.