Gear Shift Fail-Safe Release Using Solenoid Current Feedback
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Solution Overview
Problem
Existing automatic gear shifting devices fail to rapidly return to a normal gear shift ratio after an abnormality, often maintaining a fixed ratio even after the issue has been resolved, which can hinder vehicle performance.
Innovation Solution
A control device with an electronic control unit that includes an abnormality determining process, fail-safe process, relief determining process, and release process, using frictional engagement elements and solenoid valves to assess and manage gear shift ratios, allowing for rapid return to normal operation when abnormalities are temporary and resolved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gear shift ratio is fixed when an abnormality occurs, then the reliability of power transmission is improved, but the productivity is worsened due to inability to rapidly return to normal operation
Solution Approach 1:
The gear shift ratio control is made dynamic by transitioning from a static fixed state during abnormalities to a恢复正常 state automatically. The control device monitors abnormality status and dynamically adjusts the gear shift ratio based on whether the abnormality is present or has been relieved, allowing the system to adapt its behavior to current operational conditions.
Solution Approach 2:
The control device implements feedback by continuously monitoring the abnormality status and using this information to determine whether to maintain the fixed gear shift ratio or restore normal variable gear shifting. The feedback mechanism detects when the abnormality has been relieved and triggers the release of the fail-safe process, enabling automatic recovery without manual intervention.
2Reliability
If the frictional engagement element is switched to disengaged state during abnormality, then the reliability of power transmission is improved, but the loss of time increases due to prolonged fixed gear shift ratio
Solution Approach 1:
The control device prepares for potential abnormalities by having the fail-safe process ready to engage, and simultaneously monitors for abnormality relief conditions. When an abnormality occurs, the system quickly switches to the disengaged state with preliminary prepared commands, minimizing the time to enter the safe state. The system also preliminarily prepares to release the fail-safe process as soon as relief conditions are detected.
Solution Approach 2:
The gear shifting system performs self-diagnosis and self-recovery by automatically detecting when the abnormality has been relieved and autonomously releasing the fail-safe process. The control device monitors its own operational status and triggers the restoration of normal gear shifting without external intervention, enabling the system to service itself and return to optimal performance.
3Reliability
If the gear shift ratio is kept fixed after abnormality relief, then the reliability is maintained, but the ease of operation is worsened due to inability to restore normal gear shifting
Solution Approach 1:
The control device uses feedback to continuously monitor the abnormality status and automatically determine when it is safe to restore normal gear shifting operations. The feedback mechanism detects the relief of abnormalities and triggers the appropriate control actions to transition from the fixed gear shift ratio back to normal variable gear shifting, maintaining reliability while restoring full operational capability.
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
Enables appropriate power transmission during abnormalities and quick restoration of normal gear shift ratios, reducing hindrances in vehicle travel and improving drivability by accurately determining abnormality relief through turn-on current behavior analysis.
Implementation Method 1
a drive device that drives the frictional engagement element corresponding to the abnormality to the disengaged state
Implementation Method 2
frictional engagement elements...switching the frictional engagement element corresponding to an abnormality to a disengaged state
Data Source
AI summary
A control device provided in a gear shifting device includes an electronic control unit. The electronic control unit determines whether an abnormality of the gear shifting device has occurred, performs a fail-safe process of switching the frictional engagement element corresponding to an abnormality to a disengaged state and fixing the gear shift ratio of the gear shifting device when it is determined that an abnormality has occurred, determines whether the abnormality has been relieved based on a behavior of an input signal at the time of operating a drive device of the frictional engagement element corresponding to an abnormality on condition that the frictional engagement element is maintained in the disengaged state after it is determined that the abnormality has occurred, and releases the fail-safe process when it is determined that the abnormality has been relieved.