CO2 emission characteristics of hybrid electric vehicles in the tank-to-wheel (TTW) phase in plateau region.

In order to investigate the CO2 emission characteristics of hybrid electric vehicles in the tank-to-wheel (TTW) Phase in plateau region, this study conducted real-driving emission tests in Kunming using a portable emissions measurement system (PEMS). The test fleet included one internal combustion engine vehicle (ICEV) and three hybrid electric vehicles with different powertrain architectures: a plug-in hybrid electric vehicle (PHEV), a range-extended electric vehicle (REEV), and a series/parallel hybrid electric vehicle (SPHEV). The results show that the CO2 emissions of hybrid electric vehicles is significantly lower than that of ICEV under various road conditions, especially under complex urban conditions, the CO2 emission factors of ICEV are 2.56-3.27 times higher than those of hybrid electric vehicles. Hybrid electric vehicles are influenced by engine and driving characteristics, with engine characteristics having a more significant impact. The CO2 emission rates exhibit a significant nonlinear relationship with engine speed and exhaust temperature, and its R2 = 0.86-0.94. Additionally, the CO2 emission rates show a significant polynomial function relationship with vehicle velocity and acceleration. It was also found that in the Bin33-Bin40 range, the CO2 emissions of ICEV, PHEV and REEV increased with the increase of vehicle specific power (VSP), while SPHEV showed a certain emissions suppression trend. Research indicates that hybrid electric vehicles possess stronger emission reductions capabilities under multiple operating conditions, providing technical support for achieving urban low-carbon transportation goals.