重型柴油车车载排放实测与加载影响研究

采用车载排放测试仪,对2辆重型柴油卡车在空载和加载条件下进行实际道路车载排放测试.通过分析获得了油耗与排放速率的速度-加速度及其工况点的分布,发现高油耗与高排放工况点主要集中在高速加速区域,加载时油耗与排放高值随工况点分布更广;车辆在(30±2.5)km·h^-1等速及加速行驶时受加载影响最大,此时加载油耗与排放约是空载的1.6～3.2倍左右;由实测结果发现,卡车Ⅰ和卡车Ⅱ加载时油耗及CO、HC、NO_x排放因子分别是空载的1.6倍、3.5倍、1.1倍、1.5倍以及1.2倍、1.0倍、0.9倍和1.5倍,加载对油耗与NO_x排放影响最为明显,对HC影响最小,CO影响取决于车辆保养水平;卡车Ⅱ较卡车Ⅰ车型更大,发动机功率更高,相同荷载时受加载影响较小,说明重型车在发动机负荷可承受的范围内合理装载,有助于避免油耗与排放恶化,提高燃油经济性和排放水平.

Study of On-board Emission Measurement for Heavy-Duty Diesel Vehicle and Its Impact with Load

Real world vehicle emission tests were conducted on two heavy-duty diesel trucks on un-loaded and loaded condition by using a portable emission measurement system. By analysis, the results indicate high fuel consumption and emission rates are concentrated on the high speed and acceleration areas of the speed-acceleration emission maps and the areas are much wider on loaded condition. The impact of load on fuel use and emissions will be highest while the vehicle is cruising or accelerating on (30 +/- 2.5) km x h(-1), which are 1.6 - 3.2 times of those on un-loaded condition. Synthetically, the comprehensive fuel consumption and CO, HC, NO(x) emission factors of truck I and truck II on loaded condition are respectively 1.6, 3.5, 1.1, 1.5 times and 1.2, 1.0, 0.9, 1.5 times of those without load. Load has greatest impact on fuel consumption and NO(x) emission and less effect on HC emission. As for the CO emission, it depends on the maintenance of the truck. It can be figured out from the results on two trucks that the impact of same load will be lower on a vehicle with lager type and more powerful engine, which means if one vehicle is loaded on its acceptable range of GVWR, fuel use and emissions caused by heavy loads could be decreased correspondingly.