实际驾驶中冷起动对CO和NOx排放影响

Influence of Cold Start on CO and NOx Emissions in Real Driving

用便携式排放测量系统(PEMS)对3辆国六轻型车进行实际驾驶排放(RDE)试验,研究实际道路驾驶中冷起动对CO和NOx排放的影响。用CO2移动平均窗口法处理3辆车的试验数据,并在不同冷却液温度下,对比CO和NOx排放与该路段行驶里程在市区和全程的贡献率。结果发现,汽油车在不剔除冷起动工况下CO和NOx排放因子比剔除冷起动的高10.45%~53.12%和8.91%~38.74%,柴油车高62.60%~96.67%和2.11%~4.79%;较低的发动机温度导致汽油机和柴油机的CO排放严重,低温对柴油机NOx的排放有一定的抑制作用。建议后续排放法规中更加关注RDE试验的冷起动排放。

A portable emission measurement system(PEMS)was used to perform a real driving emission(RDE)test on three China 6 light-duty vehicles to study the impact of cold starting on real road driving on CO and NOx emissions.The CO2 moving average window method was used to process the test data of these vehicles,and compare the contribution rate of CO and NOx emissions and the mileage of the road section in the urban area and the whole process at different coolant temperatures.It is found that the CO and NOx emission factors including cold start are 10.45%~53.12%and 8.91%~38.74%higher than those of without cold start for gasoline vehicles,and 62.60%~96.67%and 2.11%~4.79%higher for diesel cars;Lower engine temperature leads to serious CO emissions from both gasoline and diesel engines,and low coolant temperature has a certain inhibitory effect on diesel engine NOx emissions.It is recommended that the follow-up emission regulations pay more attention to the cold start emissions of the RDE test.