Control strategy of automated manual transmission based on active synchronisation of driving motor in electric bus

Abstract

The development of electric bus has been an effective method of solving the energy crisis and environmental pollution caused by automotives. Present electric buses have fixed ratio gearboxes, however, the one-speed gearboxes cannot meet the requirements of torque and driving range simultaneously. Electric buses also have substantial requirements from batteries and driving motors. A driving system consisting of driving motor and multi-speed automated manual transmission has a simple structure, is cost-effective and easy to match. Therefore, this study focuses on the dedicated automated manual transmission structure of an electric bus without using a clutch and a synchronizer. The research also proposes the shift control strategy by actively synchronising the driving motor and by clearing the control phase division and the shift quality evaluation index. This index further studies the method of determining the range of optimal speed difference, the control strategy of the driving motor and other key techniques. The index also forms a practical shift integrated control strategy. In addition, prototype vehicle testing verifies that the strategy can shorten torque interruption time. Moreover, the absolute value of shift impact is far less than the standard value of 10 m/s 3. Finally, the success rate of the shift reaches 100%.

Fundamental limitations to no-jerk gearshifts of multi-speed transmission architectures in electric vehicles

“…A natural evolution of the single-motor fixed-ratio concept is the introduction of a multi-speed transmission. A simple concept is the manual transmission [6,7]. It consists of mounting gears on bearings, and selectively locking different gears to their transmission shafts to achieve different transmission ratios.…”