The influence of the hybridization factor on vehicle energetic consumption for different e-gearbox configurations

Abstract

To reduce the CO2 emission level for the new CAFE regulations, it is mandatory that automobile producers should choose the hybridization approach.Relevant published literature show that for a mild hybrid passenger car, increased values of the hybridization factor (HF) have marginal influence over the fuel economy for high speed values if a fixed ratio e-gearbox is used. This paper analyzes the energetic consumption for a Through the Road Hybrid Vehicle (TTR-HEV) when using a two-gear ratio transmission for the electric axle.To investigate the energetic performances, a complex model developed in a performant simulation environment is used. The energetic consumption is determined for five different test cycles in terms of speed and duration by analyzing the fuel consumption ratio (FCR) for different values of the HF.In order to compare the test cycles, the FCR parameter is used, after which the correlation with vehicle speed fluctuation (VSF) is explored.The simulation results obtained for the current application are compared with a hybrid vehicle equipped with a single gear in the rear axle. The results are also expressed in terms of CO2 emission.