| Hybrid electric bus has two sources of power, the engine and the motor. By using Hybrid Control Unit (HCU), hybrid electric bus coordinates the work of the engine and the motor, so that the work area of engine stays in the economy area, which could save energy and reduce the pollutant emissions. Hybrid electric bus typically use Automatic Mechanical Transmission (AMT), which is based on a traditional manual transmission gearbox. Automatic mechanical transmission use Transmission Control Unit (TCU) to control the selecting & shifting actuating mechanism and the clutch actuating mechanism. By simulating the action of accelerator pedal, clutch pedal, and the shift lever, TCU can achieve the function of automatic driving and shift.This paper focused on the hybrid electric bus equipped with AMT, studied the feasibility of the development of non-synchronizer AMT, established the evaluating indicators for shift quality of non-synchronizer AMT of hybrid electric bus, optimized TCU program of non-synchronizer AMT by orthogonal design method, then verified the shift quality of non-synchronizer AMT in line with company specification. The main contents of this paper include:1) On the basis of analysis of the shift process without clutch operation of the coaxial parallel hybrid electric bus AMT, the problems of synchronizer AMT are demonstrated. The feasibility of the development of non-synchronizer AMT. is discussed2) The evaluating indicators for shift quality of non-synchronizer AMT of hybrid electric bus are established. The relationship of the control strategy of hybrid electric bus equipped with non-synchronizer AMT and the shift quality are analyzed. By the car test of non-synchronizer AMT, the conclusion that the shift quality of non-synchronizer AMT is better than synchronizer AMT is reached.3) By the method of orthogonal experimental design, the three parameters that influence the shift quality are optimized. The best TCU program is concluded by analyzed the test data and redesign.4) "the Test Specifications of non-synchronizers AMT for XX Company" is established. The vehicle matching tests are carried on in accordance with the test specification.In summary, this paper optimized shift quality of non-synchronizers AMT and this research will be of great significance for the development and marketing of non-synchronizers AMT of hybrid electric bus. |
