| At present,the mainly structure type of the electric bus powertrain is a single-motor matching retarder or transmission.Although the single-motor powertrain has the characteristics of simple structure and easy control,there is a problem that it is difficult to coordinate the power and economical needs of the entire vehicle.In order to solve this problem,a dual-motor powertrain structure is proposed in this paper.The so-called dual-motor powertrain means that there are two drive motors on the same car.They can work alone to drive the car,and they can also work together to drive the car at the same time.Compared with single-motor powertrains,dual-motor powertrains with multiple drive modes not only have strong power,high motor efficiency,and small motor current load,but also improve the energy efficiency of the powertrain and provide good smoothness.This paper analyzes the structural characteristics,working principles,and advantages and disadvantages of several mature dual motor powertrains worldwide.In order to meet the requirements of powertrains for purely electric city buses,a type of dual motor matching four-speed transmission powertrain that meets the requirements of this document is identified.The working mode and control strategy of this type of dual motor are proposed,the mode selection method is formulated,and the matching route of the dual motor powertrain matching is proposed.Taking a certain type of 12-meter pure electric city bus as the research carrier,and satisfying the dynamics of the entire vehicle,the preliminary matching calculation of the powertrain parameters was performed.Tthe simulated annealing particle swarm algorithm was used to optimize the speed ratio of the gearbox and the speed ratio of the final gearbox.The optimization results show that the speed ratios of the optimized rear derailleur and main reducer are all significantly changed,and the electricity consumption after optimization is also reduced compared with that before optimization.This shows that this optimization method is conducive to improving the economic efficiency of the powertrain.In order to further prove the rationality and effectiveness of the matching method,CRUISE simulation software was used to simulate the dynamics and economy of the entire vehicle before and after optimization.The comparison of simulation results shows that after optimization of the driveline parameters,the overall vehicle economic performance is improved and the entire vehicle dynamic performance is ensured,which proves that the matching method used is reasonable and effective for improving the overall economic performance of the vehicle.The dual-motor powertrain matching method proposed in this paper is very important for solving the problem that the current electric bus is difficult to coordinate the power and economy of the whole vehicle.It can meet the needs of the whole vehicle dynamics and improve the economic performance of the powertrain.The electric vehicle driving range provides an effective research method. |
