基于车载测试的轻型汽车排放特征

选择11辆轻型汽车作为研究对象，利用车载测试系统（portable emission measurement system，PEMS）研究了轻型汽车气态污染物排放和油耗特征。结果表明：轻型汽车一氧化碳（carbon monoxide，CO）、氮氧化物（nitrogen oxides，NO_x）和总碳氢化合物（total hydrocarbons，THC）的排放因子分别为（910.4±822.6）、（58.0±48.3）和（21.6±16.1）mg/km，且其排放速率随发动机比功率-速度（vehicle specific power-velocity，VSP-v）增大而增加，冷启动期间CO、NO_x和THC的排放量占排放总量的11.2%±2.1%、3.7%±5.4%和52.7%±4.6%。轻型汽车瞬态油耗速率随VSP-v的增大而增加，车辆相对油耗在平均车速低于15 km/h时显著上升，车速在40 km/h以上时油耗随车速变化呈平稳的趋势。20 ℃时CO、NO_x和THC排放速率高于1 ℃时的排放速率；1 ℃的环境温度使油耗速率增加，尤其在车辆高速行驶时，1 ℃时其油耗速率比20 ℃时高27.1%±24.5%。

Emission characteristics of light-duty vehicles based on portable emission measurement system (PEMS)

The emission characteristics of gaseous pollutants and the fuel consumption from eleven gasoline light-duty gasoline cars were studied, using the portable emission measurement system (PEMS). The results showed that the emission factors of light-duty gasoline cars were (910.4±822.6) mg/km for carbon monoxide (CO), (58.0±48.3) mg/km for nitrogen oxides (NOx), and (21.6±16.1) mg/km for total hydrocarbons (THC), respectively. The emission rates of CO, NOx, and THC increased with the increase of vehicle specific power-velocity (VSP-v), and the emissions in the cold start phase accounted for 11.2%±2.1%, 3.7%±5.4%, and 52.7%±4.6% of the total CO, NOx, and THC mass, respectively. The transient fuel consumption rates of the light-duty gasoline cars increased with the increase of VSP-v. Vehicle relative fuel consumption increased significantly as the vehicle average speed was less than 15 km/h, and increased slightly as the vehicle average speed was over 40 km/h. The emission rates of CO, NOx, and THC at 20 ℃ were higher than those at 1 ℃. Ambient temperature also dramatically influenced vehicle fuel consumption rate. Especially when the vehicle was running at high speed, the fuel consumption rate at 1 ℃ was 27.1%±24.5% higher than that at 20 ℃.