Failure Analysis And Test Validation On Differential Coupling Device In HEV

Hybrid electric vehicle (HEV) which includes internal combustion engine and electric motor is the best solution for the transition from conventional cars to pure electric vehicles. Power-split HEVs combines the advantages of series and parallel. Its power split device is a core component. Development of efficient, reliable power split device is a key element for the development of power-split hybrid cars.Currently, the most successful power-split hybrid car is none other than Prius. Toyota has applied international patents for the power-split devices in Prius. With hybrid cars in China for further, research on the development of new type power split device needs more and more urgent.This paper relies on the National Natural Science Foundation of "The research on drive mechanism and control theory of a new power system for power-split HEV ", which puts forward a new idea of applying conventional automotive differential as power split device. In this paper, issues on the basis of previous theoretical arguments, in order to validate this idea by the bench test, carried out some research.First, through the experimental phenomena after a differential test and the failure situation about main parts of original redesign differential after the previous bench test, demonstrates the differential needs new changes design to reduce the friction if used as the power split device.Second, considering the analysis of the differential dynamic characteristics including the internal friction, by CATIA and ADAMS established a multi-joint rigid and soft body dynamic simulation model, combined with the working condition when failures occurred in previous bench test, to analyze the main reasons causing the differential pinion gear shaft failure.Third, considering the interaction between the structure and the heat, in the ABAQUS environment, the establishment of stress field and temperature field coupled finite element simulation model for pinion gear and pinion gasket to analyze the gasket stress, strain and temperature distribution at maximum load, explained severe wear pads on the pinion gear.Finally, based on the analysis, redesigned the automotive differential and test on the testing bench. The test results validate the feasibility of this new redesigned differential used as differential power split device, which laid the research foundation for the eventual development of a complete differential hybrid system(DHS) in power-split hybrid electric vehicle.