Fuel-Saving Potentials of Hybrid Electric Vehicles with Different Powertrain Configurations

The fuel-saving potentials of a hybrid electric passenger vehicle with a series, parallel, and series-parallel powertrain were investigated together with the projection for the propulsion system’s future improvements. First, combined with the genetic algorithm and different energy management strategies, a multi-parameter optimization of each propulsion system's key components’ sizes was carried out. Future fuel-saving potentials of the studied hybrid electric vehicles by 2035 were then predicted based on the Chinese industry's development goals for the key components. The results show that the influence of the powertrain configurations on the studied vehicle’s fuel consumption is 2.21% -8.07%, and the parallel hybrid system has the greatest fuel-saving potential. The hybrid vehicles can save 18.25%-32.19% fuel compared to the conventional internal combustion engine (ICE) powered vehicle if the engine’s thermal efficiency remains the same. Improvement in ICE’s thermal efficiency will become the main driver to further reduce the vehicle’s fuel consumption in the future in addition to EMS optimization, improvement in the working regions of the key components, and reduction of the key components’ energy losses.