Control of Electric to Parallel Hybrid Drive Transition in a Dual-Drive Hybrid Powertrain

Hybrid electric vehicle (HEV) powertrains have become key to developing environmentally friendly and fuel efficient vehicles. As such, companies are continually investing in developing new hybrid powertrain architectures. Ford Motor Company has developed a new “Dual-Drive” full hybrid electric vehicle that overcomes some attribute deficiencies of existing hybrid powertrain architectures due to the kinematic arrangement of the engine, motors and driveline components. This hybrid powertrain is comprised of conventional powertrain components as its base with an electric motor on the rear axle, and a crank integrated starter generator, engine and transmission on the front axle. It forms a complex configuration which provides fuel economy improvement over a conventional powertrain. However, due to this complex configuration, transitioning between electric and parallel hybrid drive modes presents a unique powertrain control challenge which requires coordinated vehicle and subsystem controls. This paper describes the control system solution to address this challenge and presents vehicle test results from a Dual-Drive HEV prototype vehicle to demonstrate the solution.