Handling method for failure of static shifting of pure electric vehicle mechanical automatic transmission

Abstract

The invention discloses a static gear shift failure handling method for a mechanical automatic transmission of an electric vehicle. First, sending a torque request to the MCU to rotate a motor rotor and thus reach the purpose of tooth staggering if the TCU recognizes the static gear shift failure; the first step can avoid the recurrence of tooth butting, shorten the gear-shifting and the second gear-shifting time, and improve the success rate of the second gear-shifting. Second, sending a zero torque request to the MCU during the second gear-shifting process, and only after detecting that thetorque of the MCU feedback power motor is 0, and only the rotating speed of the power motor is less than a set value, can the second gear-shifting action be activated. The torque of the shifting and shifting ring during the second gear-shifting process is reduced, and the torque of the power motor can be prevented from being transmitted to the wheel end, thereby avoiding the whole vehicle swayingor shaking. The success rate of the second gear-shifting is improved, and the static gear shifting smoothness of the whole vehicle is improved as well.

Description

technical field [0001] The invention relates to a method for processing static shifting failure of a mechanical automatic transmission of a pure electric vehicle, belonging to the field of shift control of the mechanical automatic transmission. Background technique [0002] The transmission is an important part of the automobile transmission system, and its important role is to realize safe and reliable transmission of power under different gears. The mechanical automatic transmission used in pure electric vehicles cancels the clutch and shift synchronizer on the basis of the traditional mechanical automatic transmission. The rotor of the motor is directly connected to the input end of the transmission through a spline. Since the rotor inertia of the motor is larger than that of the clutch, it is very easy to cause gear failure problems caused by gear coupling teeth and coupling top teeth, or due to the large resistance torque of the shift ring during the static gear shifti...

AI Technical Summary

Problems solved by technology

This method has the following problems: First, every time the static gear is engaged, the motor needs to be requested to enter the speed mode, and the gear shift action is performed after the motor speed reaches the predetermined speed

This process will inevitably lead to the extension of the shifting time by several times under normal shifting conditions, and the transmission cannot quickly respond to the driver's shifting intention; The torque and the moment of inertia of the motor rotor are transmitted to the wheel end of the vehicle, causing the whole vehicle to vibrate or sway, which seriously affects the drivability and safety of the vehicle; again, the existence of the motor speed adjustment torque and the rotor inertia moment will inevitably lead to hanging The resistance torque of the shift ring becomes larger, which further leads to an increase in the number of shift failures or a longer shift time

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