Research on the real-world gaseous emission characteristics of a plug-in hybrid electric vehicle under different initial battery state-of-charge

Abstract Plug-in hybrid electric vehicles (PHEVs) have been greatly promoted due to their advantage in both vehicle performance and energy conversion efficiency. However, real-world emission measurements are rarely conducted for PHEV under different initial battery state-of-charge (SoC). In this study, a portable emission measurement system (PEMS) was employed to investigate the real-world emissions of carbon monoxide (CO), nitrogen oxides (NOx), and carbon dioxide (CO2) from a Euro V PHEV under fully and uncharged initial battery SoC. Compared to the emissions under the uncharged state, the average emission factors (EFs) of CO, NOx, and CO2 under the fully charged state are reduced by 72.2%, 27.8%, and 29.0%, respectively. And the reduction effect on the urban road is much more significantly prominent compared to that on the rural road and highway. In addition, obvious reduction effectiveness can be found for CO EFs in different average speed bins, especially those with speeds above 100 km/h. For NOx and CO2, however, the average speed-bin EFs are reduced only when the speed is below 70 km/h, while no obvious differences can be found when the speed is above 70 km/h. Furthermore, for the average vehicle specific power (VSP)-bin emission rates, obvious reduction effectiveness is observed for CO in different speed ranges, and for NOx and CO2 in the low- and medium-speed ranges except the high-speed range.