不同环境条件下轻型车RDE测试排放特性研究

以一辆国六排放标准的缸内直喷轻型汽油车为研究对象,试验测量了不同环境温度和测试海拔对于RDE试验常规污染物排放的影响规律.试验结果表明,相比于常温(23℃)测试,更高的测试环境温度(30℃)增加了后处理装置的热负荷,更易触发燃油加浓,使试验车辆的CO和PN排放增加、NOx排放略有降低.试验发现在30℃温度下,测试海拔的增加使车辆的道路阻力需求降低,从而降低燃油加浓频率,导致CO和PN呈现随海拔升高而降低的趋势.此外,CO和市区阶段的PN排放对于RDE边界测试条件的变化具有相对较高的敏感度,表明车辆在排放标定时仍有进一步精细化的必要.

Emission characteristics of light duty vehicle in RDE tests under different environmental conditions

The effect of different ambient temperatures and altitudes on the tailpipe emissions from the RDE test was measured on a China-6emission standardlight-duty direct-injection gasoline vehicle. The results showed that the 30ºC ambient temperature increased the heat load on the aftertreatment devices compared to the 23ºC ambient temperature test, resulting in an increase in CO and PN emissions and a slight decrease in NO_x emissions from the test vehicle. It is found that at 30ºC, the increase in test altitude reduced the vehicle's road resistance requirements, which in turn reduced the frequency of fuel enrichment, resulting in a trend of decreasing CO and PN with increasing altitude. The results also show a relatively high sensitivity of CO and PN emissions in the urban phase to changes in RDE testboundary conditions, indicating that further refinement of the vehicle's emissions calibration is still necessary.