A torque control method in the process of electric vehicle driving torque passing through 0

Abstract

The invention provides a pure electric vehicle torque cross-zero torque control method, which includes obtaining the smoothed driver demand torque process, the torque positive cross-zero working condition judgment process, the torque negative cross-zero working condition judgment process, and the torque positive cross-zero working condition judgment process. The control process of crossing zero and the negative torque crossing control process; this method can solve the problem of torque very well under the premise that there is no physical buffer device on the power transmission path when the gear meshing gap is slightly large due to various reasons. The two requirements of weak meshing impact and fast torque response in the process of crossing 0 can improve the NVH quality and driving experience of the vehicle; at the same time, this method also reduces the requirements for the gear meshing clearance, which is also beneficial to reduce the cost of gear processing. , this method is of great significance for improving the cost and quality competitiveness of electric vehicles.

Description

technical field [0001] The invention relates to a torque control method in the process of an electric vehicle driving torque passing through zero, and belongs to the technical field of pure electric vehicle control systems. Background technique [0002] For pure electric vehicles, the power transmission path is all gear transmission, but limited by the cost and process of gear processing, as well as the consideration of gear structure, there is a gap between two meshing gear teeth; There are no torsional vibration dampers, clutches and other power buffering devices on the transmission path similar to those on the power transmission path of the internal combustion engine gearbox. As a result, during the operation of the electric vehicle, when the torque is switched from driving to braking energy recovery, the motor will not provide The positive torque becomes the constant switching of negative torque, and for the gears on the power transmission path, the change of the torque ...

AI Technical Summary

Problems solved by technology

[0002] For pure electric vehicles, the power transmission path is all gear transmission, but limited by the cost and process of gear processing, as well as the consideration of gear structure, there is a gap between two meshing gear teeth; There are no torsional vibration dampers, clutches and other power buffering devices on the transmission path similar to those on the power transmission path of the internal combustion engine gearbox. As a result, during the operation of the electric vehicle, when the torque is switched from driving to braking energy recovery, the motor will not provide The positive torque becomes the constant switching of negative torque, and for the gears on the power transmission path, the change of the torque driving direction makes the meshing surfaces of the two meshing gears constantly change. Since the torque transmission is relatively direct and rapid, when the gear gap is slightly larger , the meshing impact will occur during the change of the torque driving direction, which will affect the quality of the whole vehicle; the existing control strategy for torque over 0, in order to reduce the meshing impact during the torque driving direction change, often slow down the torque during the process of torque over 0. Change speed, but in this way, it will lead to slow change in the process of torque crossing 0, affecting the torque response speed, resulting in poor vehicle drivability; and if the torque change speed in the process of torque crossing 0 is increased, it will cause torque change. The impact of gear meshing during the steering process is very large, which affects the NVH quality of the whole vehicle. The current torque-over-zero control method based on this fixed torque change speed can only make a compromise between shock reduction and torque response speed, and cannot be considered at the same time.

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