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Mathematical Problems in Engineering
Volume 2014 (2014), Article ID 985652, 12 pages
Research Article

Research on Gear Shifting Process without Disengaging Clutch for a Parallel Hybrid Electric Vehicle Equipped with AMT

1State Key Laboratory of Vehicle Transmission, Beijing Institute of Technology, Beijing 100081, China
2Department of Mechanical Engineering, Politecnico di Milano, Campus Bovisa, Via La Masa 1, 20156 Milano, Italy

Received 31 October 2013; Revised 13 December 2013; Accepted 13 December 2013; Published 11 February 2014

Academic Editor: Hamid Reza Karimi

Copyright © 2014 Hui-Long Yu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Dynamic models of a single-shaft parallel hybrid electric vehicle (HEV) equipped with automated mechanical transmission (AMT) were described in different working stages during a gear shifting process without disengaging clutch. Parameters affecting the gear shifting time, components life, and gear shifting jerk in different transient states during a gear shifting process were deeply analyzed. The mathematical models considering the detailed synchronizer working process which can explain the gear shifting failure, long time gear shifting, and frequent synchronizer failure phenomenon in HEV were derived. Dynamic coordinated control strategy of the engine, motor, and actuators in different transient states considering the detailed working stages of synchronizer in a gear shifting process of a HEV is for the first time innovatively proposed according to the state of art references. Bench test and real road test results show that the proposed control strategy can improve the gear shifting quality in all its evaluation indexes significantly.