A Novel Four-Wheel-Drive Hybrid Electric Sport Utility Vehicle with Double Planetary Gears

摘要

Hybrid technology must be applied to Sport Utility Vehicles (SUVs) to meet the stringent fuel economy and emission regulations in the near future. Current hybrid SUVs realize four-wheel-drive (4WD) function which could improve its drivability and handing stability, by adding a motor to the rear axle of conventional series, parallel and power-split hybrid architectures. However, the extra motor incur more cost for the hybrid powertrain. In this paper, a novel hybrid powertrain with double outputs is proposed for 4WD SUVs, which uses a pair of planetary gears to couple the gasoline engine, two electric machines, and both front and rear wheels. The dynamics of this hybrid powertrain is built up and analyzed firstly, then Dynamic Programming (DP) is used to calculate the optimal controls and best fuel economy. Results indicates this 4WD hybrid powertrain shows greater fuel economy improvement than conventional 4WD system.