Mechanical designs, energy management, and performance assessment of a novel hybrid electric scooter

This research aims for developing a simple but novel hybrid electric scooter (HES) for enhancing output performance compared to electric scooters and engine scooters. The mechanical system, mechatronics, and vehicle control unit (VCU) were designed and implemented on a 125 c.c. engine vehicle. For the mechanical modification, it mainly includes: 1) integrating a 1.5kW wheel motor on the hub with a new rear arm, 2) equipping a one-way clutch between the continuously variable transmission (CVT) and the hub, 3) producing a "folded" tail pipe under the chassis. For the mechatronics, it includes: 1) modifying the accelerator with electric signal, 2) integrating a step motor on the engine throttle valve, 3) adding a programmable rapid prototyping controller to be the VCU and the harness for measurement/control signals was designed. For the energy management, three operation modes were designed according to the voltage of the accelerator: 1) EV (electric vehicle) mode: the VCU delivers the torque signal to the motor control unit (MCU) while the wheel motor was the single power source; 2) HEV-ready (hybrid electric scooter-ready) mode: before the HEV mode, a relay was controlled to activate the starter to drive the engine to the idle status; 3) HEV mode: both the motor and the engine drive the scooter with proper energy management. The rule-based control was coded on the Matlab/Simulink/Stateflow platform and was downloaded to the rapid prototyping controller. To evaluate the performance, the completed HES was tested on a chassis dynamometer with a speed tracking auto-pilot under the ECE 40 driving pattern. The functions of the HEV system were verified. The key parameters were measured and analyzed. The results prove that the novel HES operates well with the novel and simple designs. More operation modes and theoretical-based energy management will be completed and verified in the future.