Study on Plateau Emission for Plug-in Hybrid Electrical Vehicle

China 6b emission standard GB18352 specifies the pollutant emission limit of type I normal temperature cold start test, but does not specify the altitude conditions, which means that all vehicles in plateau conditions of plateau should also meet the normal temperature limit requirements, in addition to the actual driving pollutant emission test of type II stipulates corresponding conformity factor and altitude expansion conditions. The above tests all need to consider emission performance of the engine under plateau conditions. There have been studies on the emission test of traditional fuel vehicles under plateau conditions, but relatively few studies on the altitude emission of new type plug-in hybrid vehicles. Different from the performance of conventional vehicles, the first start time of the plug-in vehicle engine in the WLTC (Worldwide Harmonized Light Vehicles Test Cycle) cycle is closely related to the balance energy, and the start time has a greater impact on the WLTC cycle emission results. Purpose of this paper is to perform RDE (Real Drive Emission) emission and room temperature emission test of a plug-in hybrid vehicle at the altitude of Kunming, as well as analyze the corresponding results, and finally summarize the characteristics of the Plug-in Hybrid Electrical Vehicle in plateau conditions. The research shows that for plug-in hybrid vehicles, different balance SOC set has a big difference in emission performance. Compared with balance SOC level B, balance SOC level A has 51% more CO emissions, 27% more THC emissions, 13% more NOx emissions, and 63% more PN emissions. To meet the emission requirements, balance SOC (State Of Charge) level needs to be optimized according to the altitude conditions (atmospheric pressure) to meet emission limit requirements at normal temperature, and the performance of RDE in plateau and plateau mountain areas has no big difference from that of plain RDE for the overall travel, but urban condition has deteriorated, for example CO emissions under normal driving conditions in high-altitude and high-altitude mountainous areas are 6.3 and 6.6 times higher than those under plain conditions in urban conditions, respectively. NOx is 1.1 and 1.6 times higher, and PN is 1.3 and 3.1 times higher.