To properly evaluate the cold-start emissions of vehicles, four light-duty vehicles were selected to complete a Real Driving Emissions (RDE) test. The analysis and evaluation of the RDE test results reveal that the cold-start emissions account for a significant proportion of the urban trip emissions, and that the moving average window (MAW) method is not suitable for statistically processing the RDE test data that include the cold-start emission data. Additionally, three on-road emission tests including a cold-start test and two hot-start tests at different vehicle thermal states were designed to evaluate the effect of the initial vehicle thermal state on the vehicle start emissions. The results demonstrate that the thermal state of the TWC converter thermal state has a more direct and important effect on the cold-start emissions in the RDE test. Via a comparative analysis of the instantaneous characteristics of pollutant emission rates, fuel–air equivalent ratios, catalytic converter temperatures, vehicle trip dynamic parameters, etc., it is inferred that driving behavior has a more significant and sensitive impact on the cold-start emissions than on the non-cold-start emissions in the RDE test. Based on the RDE tests performed at different ambient temperatures, it is also indicated that the impact of the ambient temperature on the cold-start emissions is only a secondary factor relative to driving behavior. As a result, the trip dynamic conditions, specifically those for the cold-start period, should be set more reasonably and effectively in future RDE regulations to ensure the consistency of the cold-start emission test results.

为了正确评估车辆的冷启动排放，选择了四辆轻型车辆来完成实际驾驶排放（RDE）测试。RDE测试结果的分析和评估表明，冷启动排放量占城市出行排放量的很大一部分，而移动平均窗（MAW）方法不适用于统计处理包含以下内容的RDE测试数据：冷启动排放数据。此外，还设计了三种道路排放测试，包括冷启动测试和两种在不同车辆热状态下的热启动测试，以评估初始车辆热状态对车辆起动排放的影响。结果表明，在RDE测试中，TWC转换器的热状态对冷启动排放有更直接和重要的影响。通过对污染物排放速率，燃油-空气当量比，催化转化器温度，车辆行驶动态参数等的瞬时特性进行比较分析，可以推断出驾驶行为对冷启动排放有更重要和更敏感的影响比RDE测试中的非冷启动排放。基于在不同环境温度下执行的RDE测试，还表明环境温度对冷启动排放的影响只是相对于驾驶行为的次要因素。因此，应在未来的RDE法规中更合理，更有效地设置跳闸动态条件，尤其是冷启动期间的条件，以确保冷启动排放测试结果的一致性。