Vehicle Power Transmission Control Apparatus Hydraulic Pressure Learning
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Solution Overview
Problem
The existing vehicle power transmission systems face inaccuracies in engagement transitional hydraulic pressure command values during transitions from a non-drive to a drive operating position, leading to potential over or under-supply of hydraulic pressure, which can result in prolonged engagement times and decreased response accuracy.
Innovation Solution
An electronic control unit is implemented to monitor and adjust the engagement transitional hydraulic pressure command values based on the duration of the operating position transition, learning to increase the command value if the transition time exceeds a target and reducing it if the transition is shorter, while prohibiting learning when the operating time exceeds a predetermined limit to prevent excessive pressure supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If learning control is executed to adjust the hydraulic pressure command value based on engagement transition time, then the engagement response time is improved, but the accuracy of learning decreases when the operating time is long
Solution Approach 1:
The patent changes the parameter of learning execution based on the operating time condition. When the operating time from non-drive to drive position exceeds a predetermined threshold, the learning control is prohibited. This parameter-based conditional control prevents inaccurate learning that would occur under prolonged operating conditions, thereby maintaining learning accuracy while still optimizing engagement response time under normal conditions.
Solution Approach 2:
The system implements feedback control by monitoring the operating time and engagement transition time, comparing them against predetermined thresholds, and adjusting the learning execution accordingly. This feedback mechanism ensures that learning is only performed when conditions are favorable for accurate measurement, preventing the degradation of learning accuracy while maintaining optimal engagement performance.
2Speed
If the hydraulic pressure command value is increased through learning to reduce engagement transition time, then the engagement speed is improved, but excessive or deficient hydraulic pressure may be supplied
Solution Approach 1:
The patent adjusts the hydraulic pressure command value parameter through learning control, but only under specific conditions where the operating time is within the predetermined threshold. This conditional parameter adjustment ensures that the hydraulic pressure is optimized for faster engagement while preventing excessive or deficient pressure supply that would compromise reliability.
Solution Approach 2:
The system applies partial learning adjustment rather than uncontrolled increases in hydraulic pressure. By limiting learning execution to cases where operating time is below the threshold, the system applies just enough pressure adjustment to improve engagement speed without risking excessive pressure supply, thereby maintaining both speed and reliability.
3Duration of action of moving object
If the operating time from non-drive to drive position is long, then the hydraulic pressure rises gradually, but the engagement transition time becomes longer than the target time
Solution Approach 1:
The patent changes the execution parameter of learning control based on the operating time duration. When the operating time exceeds the predetermined threshold, learning is prohibited to prevent further delays. This parameter-based control strategy addresses the issue by preventing the system from attempting to compensate for delays that cannot be recovered, thereby maintaining realistic engagement transition time expectations.
Data Source
AI summary
A control apparatus includes an ECU that is configured to: start engagement transition control for outputting an engagement transitional hydraulic pressure command value that causes an engagement device to be actuated from a released state toward an engaged state from when an operating member is displaced from a non-drive operating position; when an engagement transition time is longer than a target time, learn the engagement transitional hydraulic pressure command value such that the engagement transitional hydraulic pressure command value increases; when the engagement transition time is shorter than the target time, learn the engagement transitional hydraulic pressure command value such that the engagement transitional hydraulic pressure command value reduces; and prohibit learning of the engagement transitional hydraulic pressure command value or invalidate the learned engagement transitional hydraulic pressure command value, when the operating time of the operating member is longer than a predetermined time.