Torque Converter Lock-Up Clutch With Sealed Cooling Flow Control
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Solution Overview
Problem
Existing torque converter designs with complex clutch systems, such as three or four-pass designs, increase cost and complexity while aiming to improve clutch controllability and fuel economy, necessitating a simpler and less expensive alternative that maintains controllability.
Innovation Solution
A torque converter design featuring a lock-up clutch with a piston and seal ring configuration that forms fluid chambers, utilizing a valve to control fluid flow based on pressure differences and incorporating forced cooling fluid paths to reduce complexity and cost, while maintaining clutch controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex clutch systems with multiple flow passages are used, then clutch controllability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The torque converter is divided into distinct functional zones: a sealed clutch apply pressure chamber isolated from a cooling passage, with separate fluid pathways for pressure control and thermal management. This segmentation allows independent optimization of clutch controllability and cooling efficiency without requiring complex integrated flow passages.
Solution Approach 2:
A seal ring is introduced as an intermediary component between the clutch apply pressure chamber and the cooling passage. The seal ring creates a fluid barrier that prevents mixing between apply pressure fluid and cooling fluid, enabling simple separate pathways while maintaining effective thermal management and clutch control.
2Reliability
If complex clutch systems with multiple flow passages are used, then clutch controllability is improved, but manufacturing cost increases
Solution Approach 1:
The torque converter is divided into distinct functional zones: a sealed clutch apply pressure chamber isolated from a cooling passage, with separate fluid pathways for pressure control and thermal management. This segmentation allows independent optimization of clutch controllability and cooling efficiency without requiring complex integrated flow passages.
Solution Approach 2:
A seal ring is introduced as an intermediary component between the clutch apply pressure chamber and the cooling passage. The seal ring creates a fluid barrier that prevents mixing between apply pressure fluid and cooling fluid, enabling simple separate pathways while maintaining effective thermal management and clutch control.
3Temperature
If forced cooling fluid flow is passed through the lock-up clutch, then cooling efficiency is improved, but fluid leakage risk increases without proper sealing
Solution Approach 1:
A seal ring is introduced as an intermediary component between the clutch apply pressure chamber and the cooling passage. The seal ring creates a fluid barrier that prevents mixing between apply pressure fluid and cooling fluid, enabling simple separate pathways while maintaining effective thermal management and clutch control.
Solution Approach 2:
The cooling function is extracted from the clutch pressure control system by creating a separate cooling passage that does not mix with the clutch apply pressure chamber. This extraction allows forced cooling fluid to flow through the lock-up clutch for efficient thermal management while the seal ring prevents leakage into the pressure control system.
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 design achieves improved clutch controllability and reduced complexity and cost by using a two-pass torque converter system with a sealed clutch release pressure chamber, allowing for efficient fluid flow management and cooling, thus enhancing vehicle efficiency and NVH (Noise, Vibration, and Harshness) performance.
Implementation Method 1
A valve may be connected to the piston on the second axial side and configured to seal the first opening in response to a difference between a first pressure in the first fluid chamber and a second pressure in the second fluid chamber
Implementation Method 2
the front cover may include a second opening defined therein located radially outward of the seal ring and arranged such that forced cooling fluid flow passes through the lock-up clutch to the second fluid chamber via the second opening when the lock-up clutch is closed
Data Source
AI summary
A torque converter includes a front cover, an impeller having an outer shell non-rotatably connected to the front cover, and a turbine. A lock-up clutch is disposed axially between the front cover and the turbine. The lock-up clutch includes a piston axially displaceable and having a first opening extending from a first axial side facing the front cover to a second axial side facing the turbine. A seal ring is fixed to the front cover and sealed to the piston. A first fluid chamber is formed at least in part by the piston and the turbine, and a second fluid chamber is formed at least in part by the front cover, the seal ring, and the piston. A valve is connected to the piston and is configured to seal the first opening in response to a pressure difference in the first and second fluid chambers.