Torque Converter Clutch Switch Valve With Internal Pressure Limiting
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Solution Overview
Problem
Current torque converter clutch (TCC) systems lack a pressure limiting mechanism to protect the torque converter from high fluid pressures, which can lead to damage and failure, especially in upgraded transmissions where line pressures exceed 250 psi.
Innovation Solution
A TCC switch valve with an internal limit valve is introduced, featuring a plunger and piston configuration that allows fluid communication to be controlled, preventing overpressure from reaching the apply port and thus limiting the maximum line pressure to the TCC, mimicking OEM functionality without modifying the existing valve body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If line pressure is increased to improve transmission performance, then power transmission capability is improved, but torque converter clutch reliability deteriorates due to overpressure damage
Solution Approach 1:
A limit valve is introduced as an intermediary component between the line pressure source and the torque converter clutch apply port. This limit valve mediates the pressure transmission by allowing normal high line pressure to pass through during normal operation while blocking excessive pressure from reaching the TCC, thus protecting the TCC from overpressure damage while maintaining the power transmission capability of the upgraded transmission system.
2Reliability
If a pressure limiting mechanism is added to protect the torque converter clutch, then torque converter clutch reliability is improved, but device complexity increases
Solution Approach 1:
The limit valve is merged with the existing TCC switch valve assembly, integrating the pressure limiting function into the already-present valve structure. This combination allows the system to gain overpressure protection capability without adding a completely separate limit valve assembly, thereby reducing the increase in device complexity while still improving torque converter clutch reliability.
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 limits apply pressure to prevent damage to the torque converter clutch, maintaining normal drivability while protecting the TCC from excessive pressures, and can be easily installed as a drop-in kit within the OEM switch valve body.
Implementation Method 1
A first spring biases the plunger towards the first position in the bore of the TCC switch valve body
Implementation Method 2
A second spring biases the limit valve towards the second position in the bore of the plunger
Implementation Method 3
the limit valve is configured such that an overpressure from the line-in port overcomes the second spring to move the piston towards the first position
Data Source
AI summary
A switch valve for a torque converter clutch switch valve body having a bore with line-in and apply ports. The switch valve has a plunger with a bore defined therein. The plunger is configured for moving in the switch valve body bore between first and second positions, whereby fluid communication with the line-in port is prevented and permitted in the first and second positions, respectively. A first spring biases the plunger towards the first position. A limit valve is positioned in the bore of the plunger and has a piston configured for moving in the plunger bore between first and second positions, whereby fluid communication with the apply port is prevented and permitted in the first and second positions, respectively. A second spring biases the limit valve towards the second position. Overpressure from the line-in port moves the piston towards the first position to prevent overpressure to the apply port.