Defect Analysis and Innovation Design of Synchronizer for Clutchless Automatic Mechanical Transmission

The synchronizer is a key component of automatic mechanical transmission(AMT)equipped in electric vehicles,but the inertial lock-ring synchronizer(ILRS)commonly used there is not suitable especially for pure electric vehicles without a clutch because of big shift impact.To make the shifting process rapid and smooth,a new synchronizer named pressure-controllable friction ring synchronizer(PCFRS)was designed.Initially,the inevitable shortcoming of ILRS was verified by simulation and test.Furthermore,the mechanical characteristics and advantages of the new synchronizer over ILRS were analyzed.Then,the formulations describing the dynamic transmission based on the working mechanism of the PCFRS were established.Finally,the shifting simulation results with PCFRS and ILRS based on the same operating conditions were compared and analyzed.The research shows that the PCFRS can meet the main shifting evaluation index of an AMT without complex control methods,as well as it takes only 0.2406 s to finish the comfortable and zero-speed-difference shifting.The shifting quality of PCFRS is better than that of the ILRS.It lays a foundation for using the new synchronizer as a part of clutchless AMTs equipped in pure electric vehicles.

Experimental and simulated studies on hydraulic buffering valve for ZF-4WG308 power-shift transmission

The structure and working principle of a hydraulic buffering valve for a power-shift transmission ZF-4WG308 were studied comprehensively, and a model of the hydraulic buffering valve was developed with AMESim. A bench test was conducted on a buffering valve for transmissions(ZF-4WG308) and the test results agree well with the simulated results. Further more, the influences of the key parameters of the valve on the buffering performance were also studied in details.

Study on shift schedule saving energy of automatic transmission of ground vehicles

To improve ground vehicle efficiency, shift schedule energy saving was proposed for the ground vehicle automatic transmission by studying the function of the torque converter and transmission in the vehicular drivetrain. The shift schedule can keep the torque converter working in the high efficiency range under all the working conditions except in the low efficiency range on the left when the transmission worked at the lowest shift, and in the low efficiency range on the right when the transmission worked at the highest shift. The shift quality key factors were analysed. The automatic trans-mission's bench-test adopting this shift schedule was made on the automatic transmission's test-bed. The experimental results showed that the shift schedule was correct and that the shift quality was controllable.