Power delivery co-ordination to meet driver’s demand in a mild hybrid vehicle with automated manual transmission

Abstract

In this paper a power delivery control strategy for a passenger mild hybrid vehicle is developed and described with simulation results. The vehicle is equipped with Integrated Starter Alternator (ISA) and Automated Manual Transmission (AMT). The transmission and engine control units, and ISA torque control for boosting and regenerative braking are optimized according to the requirements of the power delivery from the vehicle power sources to the driven wheels, and the requirements of driver’s demand as well. A gear-shifting strategy for AMT is developed to extract the AMT up-shift and down-shift maps. These maps are utilized for proper gear-shifting and emulating the shifting strategy of a professional driver. An ISA power management strategy is also proposed and described which considers the driver’s wheel torque demand as well as the state of charge (SOC) of the battery. In the case of braking, the ISA produces braking force in parallel with the mechanical brake system. A braking control unit is also presented that computes the mechanical and electrical braking forces required to meet driver’s braking force command. The electrical braking captures the vehicle kinetic energy as much as possible without reducing the stability. The feasibility of operation of the vehicle controller has been demonstrated by simulating the vehicle with a driver model.