Actuator Pressure Stabilization in Multi-Speed Transmissions
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Solution Overview
Problem
Closed-end variable-bleed solenoids in automatic transmissions experience destabilization and increased output pressure during low transmission input speed and high hydraulic fluid temperature conditions, leading to unstable actuator performance and noticeable shifts to the vehicle operator, with existing solutions requiring costly hardware changes or introducing new leakage issues.
Innovation Solution
An electronic control system that detects the trim phase of torque transmitting mechanisms and applies alternating 'pressure off' and 'pressure on' commands to stabilize actuator output pressure, using a closed-end, variable-bleed solenoid valve, by issuing modified pressure commands based on transmission input speed and fluid temperature thresholds to maintain stable actuator performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed-end variable-bleed solenoids are used to control torque transmitting mechanisms, then actuator output pressure can be controlled, but under low transmission input speed and high hydraulic fluid temperature conditions, the actuator output pressure becomes unstable and increases, leading to destabilization
Solution Approach 1:
The patent applies periodic action by cycling the solenoid between energized and de-energized states during the trim phase to prevent destabilization. The electronic control alternates between applying and releasing pressure to the actuator in a periodic manner, which stabilizes the actuator output pressure under low speed and high temperature conditions where continuous pressure application would cause instability.
Solution Approach 2:
The patent changes the control parameters by monitoring transmission input speed and hydraulic fluid temperature, and adjusting the pressure control strategy accordingly. When low speed and high temperature conditions are detected, the system transitions from continuous pressure application to periodic pressure cycling, effectively changing the control parameters to maintain stability.
2Reliability
If existing hardware changes are implemented to address actuator destabilization, then actuator performance may be improved, but the solution becomes costly and may introduce new leakage issues
Solution Approach 1:
The patent replaces potential mechanical hardware modifications with an electronic control solution. Instead of changing the physical actuator design or adding mechanical components to address destabilization, the system uses electronic control logic to monitor conditions and adjust pressure application timing, thereby avoiding hardware complexity and potential leakage issues.
Solution Approach 2:
The existing actuator system serves itself through intelligent control. The electronic control system monitors the operating conditions and self-adjusts the pressure control strategy without requiring external hardware modifications. The system uses its existing sensors and control capabilities to stabilize actuator performance, making the system self-sufficient.
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 solution effectively stabilizes actuator output pressure during low transmission input speed and high fluid temperature conditions, preventing destabilization and providing smoother shifts without the need for costly hardware changes or introducing new leakage issues, thus enhancing the reliability and efficiency of torque transmitting mechanisms.
Implementation Method 1
an electro-hydraulic actuator in fluid communication with the fluid supply, where the electro-hydraulic actuator is configured to provide an output pressure to a torque transmitting mechanism
Implementation Method 2
an electro-hydraulic actuator in fluid communication with the fluid supply
Data Source
AI summary
A method for managing torque transmitting mechanism actuator output pressure under low supply pressure conditions is provided. The method is executable to control engagement of a torque transmitting mechanism during such conditions.