Automatic Shift Control for Quiet 4WD-to-2WD Disengagement
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Solution Overview
Problem
Existing vehicles with automatic transmission systems experience impact and noise due to clashes of meshing teeth during switching between two-wheel drive and four-wheel drive modes, affecting driving experience.
Innovation Solution
An automatic shift control method that includes an elastic release operation to unload torque, followed by a position adaptive operation to stabilize the rotational speed of the moving component, and then controlled meshing and separation to achieve a completely disengaged position without impact or noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a disengaging and engaging apparatus is used to switch between two-wheel drive and four-wheel drive modes, then power switching capability is improved, but impact and noise occur during mode switching
Solution Approach 1:
The method applies preliminary action by performing speed synchronization before the actual disengagement. The control system pre-adjusts the rotational speeds of the input shaft and output shaft to be substantially equal before the moving component fully disengages, ensuring that meshing teeth are at the same rotational position when separation occurs, thereby preventing impact and noise during mode switching
Solution Approach 2:
The control system continuously monitors the rotational speeds of the input shaft and output shaft through sensors and uses feedback control to adjust the electric machine's torque output. This feedback mechanism ensures that speed synchronization is achieved and maintained throughout the disengagement process, preventing relative speed differences that would cause meshing tooth clashes
2Productivity
If the disengaging and engaging apparatus disengages quickly to reduce switching time, then productivity is improved, but relative oscillation of rotational speed increases causing clashes
Solution Approach 1:
The method applies dynamics by implementing a dynamic control strategy that adjusts the disengagement process based on real-time rotational speed conditions. The control system modulates the electric machine torque during disengagement to actively dampen relative oscillations between input and output shafts, maintaining speed synchronization even during rapid mode transitions, thus preventing meshing tooth clashes while enabling quick switching
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method reduces or eliminates speed differences and impacts during mode switching, enabling imperceptible automatic shift control and improving driving experience by avoiding clashes and noise.
Implementation Method 1
controlling a rotor speed of the first electric machine of the vehicle to zero rotational speed to convert kinetic energy of the first electric machine into electric energy for storage or power supply
Data Source
AI summary
An automatic shift control method, apparatus, device and storage medium. A vehicle is controlled to perform an elastic release operation in response to a drive switching request. When unloading torque of a first electric machine of the vehicle is completed, a moving component of a disengaging and engaging apparatus of the vehicle is controlled to perform a position adaptive operation. Meshing direction and separation control is performed on the moving component when a rotational speed of the moving component reaches a stable state, to cause the moving component to move in a disengaging direction to a completely disengaged position, and switch of the vehicle from a four-wheel drive power mode to a two-wheel drive mode is completed.