柴油轿车冷起动颗粒排放特性的试验研究

An Experimental Study on the Particle Emission Characteristics of a Diesel Car During Cold Start

使用排气颗粒数量与粒径分析仪对一辆帕萨特柴油轿车进行了冷起动和热起动对比试验,研究其起动过程的颗粒排放特性。结果表明,柴油轿车冷起动颗粒排放数量浓度与热起动相比显著增加,其中,聚集态颗粒数量浓度增加明显,而核模态颗粒数量浓度差别不大;冷起动排放颗粒表面积浓度、体积浓度和质量浓度显著高于热起动;冷起动过程燃油消耗量也比热起动成倍增加。因此,冷起动不但造成颗粒排放恶化,且严重影响柴油轿车的燃油经济性。

By using an engine exhaust particle sizer, the cold start and hot start tests on a Passat diesel car are conducted to study its particle emission characteristics during starting. The results show that the total particle number concentration in cold start is significantly higher than that in hot start, in which the number concentration of accumulation mode particles increases markedly whereas there is little difference in the number concentration of nu- cleation mode particles in cold start and hot start. The particle concentrations in surface area, volume and mass in cold start is much higher than that in hot start. The fuel consumption in cold start is also doubled compared with that in hot start. Thus cold start not only results in the deterioration of particle emission but also seriously affects the fuel economy of a diesel car.