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To optimize the power and economic performance of battery electric passenger vehicles, an 8.5-m-long battery electric passenger vehicle was selected as the research subject. The simulated-annealing particle-swarm-optimization (SAPSO) algorithm was applied to optimize the two-speed gearbox and transmission ratio of the vehicle. With the opening of the accelerator pedal and speed as variables, a comprehensive gear shift schedule that considered both the power and economic performance was established. The comprehensive gear shift schedule curve was defined in the model built in the ADVISOR software. The transmission ratio was jointly optimized using the ADVISOR and ISIGHT software, and then the ADVISOR simulation software was used to analyze the economic and dynamic performances corresponding to the optimized transmission ratio. Finally, we compared the power and economic performances of the vehicle before and after transmission ratio optimization, the results of which showed that after the optimization, the maximum speed, climbing gradient, and 0–50 km/h acceleration time of the vehicle were greatly improved, and the driving range was slightly shortened. This enabled performance advantages of the battery electric passenger vehicle by balancing the power and economic performances of the vehicle.

Abstract. There is high market demand for new energy vehicles. And the driving system of new energy bus gets improved day by day. Within the performance studies on core components such as electric machinery, controller, battery and gearbox and within the vehicle system performance matching and conformity, it is an important part to accurately and quickly construct a test bench of the new energy bus hybrid system. To achieve ideal results of the bench test, the paper probes into the test objects, the test items, the site layout and technology assessment and others, and has taken every relevant factors into consideration.

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Abstract. Using tool such as torque wrenches, air guns, speed sensors and bolt fastening analyzer, the causes of flywheel bolt fracture of ISG motor was analyzed, respectively from the fixed structure of hybrid bus, tightening performance of bolt and clutches shock characteristics. The results show that lack of tightening torque and excessive torque occurred from clutches shock were the major causes of over-fatigue about flywheel bolt for hybrid bus. The solutions were proposed to prevent the connecting fracture of flywheel bolt, included using level 10.9 Hexagon bolt to increase the tensile strength, and using torque wrench to reset torque value, and insuring clutches engagement synchronously to reduce torque shocks.