A shift control method and system

Abstract

The present invention proposes a shift control method, comprising the following steps: obtaining a target rotational speed; controlling the rotational speed of the motor to reach the target rotational speed; when the rotational speed of the motor reaches the target rotational speed, controlling the synchronizer to start, obtaining the target torque, The torque of the motor reaches the target torque; when the torque of the motor reaches the target torque, shifting is performed. According to the control method of the present invention, first make the motor reach the target speed, and then control the torque of the motor to reach the target torque, which can reduce the speed difference between the input shaft and the output shaft of the gearbox when shifting gears under bad road conditions, so that the vehicle can shift gears reliably . The invention also proposes a shift control system.

Description

technical field [0001] The invention relates to a shift control method and system. Background technique [0002] At present, most electric vehicles have canceled the clutch in the traditional transmission system. During the shifting process, the motor rotates freely without output torque. The speed of the output shaft and the input shaft of the gearbox are synchronized by the function of the synchronizer. When the synchronization is achieved, The shift fork pushes the sliding gear sleeve to engage with the splined ring gear on the gear side to complete the gear; or by controlling the torque of the motor to make the speed of the input shaft of the gearbox reach the target speed, so that the speed of the output shaft and the input shaft of the gearbox The difference is reduced to synchronize. [0003] The above two technologies can make the gearbox quickly respond to the shift signal and complete the shift under good road conditions, but have high requirements for the samplin...

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Problems solved by technology

[0003] The above two technologies can make the gearbox quickly respond to the shift signal and complete the shift under good road conditions, but have high requirements for the sampling accuracy of the sensor and the control accuracy of the motor, and for typical road conditions such as climbing a steep slope or When the road surface is muddy, the resistance coefficient of the road surface is large, and the output shaft speed of the gearbox will drop, resulting in an increase in the speed difference between the input shaft and the output shaft of the gearbox. The torque of the motor is controlled for speed regulation and the friction torque through the synchronizer is not enough to eliminate the gearbox The speed difference between the input shaft and the output shaft of the gearbox will cause the synchronization failure of the input shaft and the output shaft of the gearbox, resulting in the failure of shifting

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