Control strategy design and experimental research on a four-shaft electronic continuously variable transmission hybrid electric vehicle

Abstract

A new electromechanical power-splitting full-hybrid transmission with two shifting elements, namely a four-shaft planetary gear and an electronic continuously variable transmission, is introduced in this paper. This transmission was developed with the aim of combining all the advantages of an internal combustion engine and two electric motors in an optimal way so as to improve the power performance and the fuel economy. The architecture and analogy of the four-shaft planetary gear are analysed, a control strategy is designed, and the engine management system and hybrid control system are calibrated. To evaluate the performance, the control strategy and the calibrated results, nine tests were performed as per the New European Driving Cycle under various initial conditions, different maps and different thresholds. The test results indicate that a four-shaft planetary gear, electronic continuously variable transmission hybrid electric vehicle can realize good fuel economy and good emissions performance except for nitrogen oxide emissions. The best fuel consumption obtained was 5.4 l/100 km. The amount of nitrogen oxide emissions needs to be decreased by optimizing the control strategy of the hybrid control system and calibration of the engine management system in future research.