满足国六排放的缸内直喷汽油车污染物排放特性试验研究

以满足国六排放的某缸内直喷轻型汽油车为研究对象,试验研究了该车国六Ⅰ型测试循环(WLTC循环)排放的CO、THC、NOx和固态颗粒数量,以及包含挥发性/半挥发性组分的颗粒物数量和粒径分布特性.结果表明:WLTC循环工况覆盖范围广、车速高、加速度大的特点导致污染物排放增加;车辆冷机起动、暖机过程、瞬态过渡工况和高速大负荷工况对车辆的污染物排放影响较大,研发合理的车辆起动、催化剂起燃和暖机热管理策略、提高发动机瞬态过渡工况响应性是控制排放的重点;包含挥发性/半挥发性组分的颗粒物数量排放呈单峰分布,在15 nm附近达到峰值.

Experimental investigation on emission characteristics from a gasoline direct injection light-duty vehicle certified to meet China VI regulation

The gaseous pollutants (CO, THC, NO_x), solid particles number, particles number containing volatile/semi volatile components, as well as particles size distribution characteristics of the light-duty gasoline direct injection (GDI) vehicle certified to meet China VI were experimentally studied under worldwide harmonized light vehicle test cycle(WLTC). The results show that the gaseous pollutants and solid particles number increased due to the wide range of driving condition, higher speed and acceleration of WLTC. The gaseous pollutants and solid particles number increased during the phase of cold-start, warm-up operation condition, transient conditions and super high speed with heavy load. The effective control strategies of start, light-off of catalyst, warm-up of engine, and transient conditions will suppress the emissions obviously. The particle number containing volatile/semi volatile components behave a single peak distribution, reaching the peak near particle size 15 nm.