Three-Passage Torque Converter Lockup Clutch to Prevent Ballooning
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Solution Overview
Problem
Conventional two-passage torque converters face issues such as ballooning, clutch damage due to lack of lubrication, delayed lockup engagement, and inability to increase stall speed without causing clutch damage.
Innovation Solution
A torque converter with a lockup clutch and three oil passageways is introduced, which controls oil pressure, prevents ballooning, includes lubrication grooves for enhanced cooling, maintains the piston in the released position, allows charge pressure drainage, and ensures continuous fluid circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the torque converter pressurizes the entire interior to apply the lockup clutch, then the clutch engagement force is improved, but the torque converter balloons and the impeller deforms
Solution Approach 1:
The torque converter interior is divided into two separate hydraulic passages: Passage A (apply passage) that supplies pressure only to the clutch apply side, and Passage B (release passage) that maintains pressure on the release side. This segmentation allows localized pressurization for clutch engagement without pressurizing the entire converter interior, preventing ballooning and impeller deformation.
2Reliability
If solid clutch linings without lubrication grooves are used to maintain sealing, then the seal integrity is improved, but the clutch cooling and lubrication are insufficient causing heat buildup
Solution Approach 1:
Lubrication grooves are added to the clutch linings to provide localized lubrication and cooling channels. These grooves allow lubricating oil to reach the clutch friction surfaces directly, improving heat dissipation and reducing temperature without compromising the overall seal integrity of the clutch assembly.
3Productivity
If oil flow through passageway A is restricted, then the hydraulic circuit efficiency is improved, but the clutch piston cannot maintain released position causing clutch dragging
Solution Approach 1:
A check valve is introduced as an intermediary component in Passage A to ensure unidirectional oil flow. The check valve maintains sufficient oil pressure to keep the clutch piston in the released position during high RPM conditions while allowing efficient hydraulic operation during normal conditions, preventing clutch dragging without sacrificing circuit efficiency.
4Device complexity
If the lockup clutch is engaged by changing oil flow direction, then the clutch engagement control is simplified, but the lockup engagement is delayed due to centrifugal forces
Solution Approach 1:
The hydraulic system is pre-configured with separate apply and release passages that can independently control clutch engagement. The apply passage (A) and release passage (B) are designed to allow simultaneous or near-simultaneous pressure changes, eliminating the sequential delay caused by centrifugal forces that prevent immediate oil flow redirection in conventional single-passance systems.
5Speed
If charge pressure is drained to increase stall speed, then the turbocharger spooling performance is improved, but the clutch drags and fails in conventional systems
Solution Approach 1:
The hydraulic system is segmented into independent apply and release passages, allowing the release passage (B) to be drained for increasing stall speed while the apply passage (A) maintains sufficient pressure to prevent clutch dragging. This segmentation enables charge pressure drainage for turbo spooling without compromising 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 three-passage torque converter effectively prevents ballooning, enhances clutch resilience and heat dissipation, ensures timely lockup engagement, increases stall speed without damaging the clutch, and maintains lower internal temperatures.
Implementation Method 1
The lubrication grooves in the lining allow lubricating oil to reach the clutch and, thus, improve clutch resilience and heat dissipation
Implementation Method 2
The fiber material of the clutch plates 20 act as a seal to separate passageways A and B from one another
Data Source
AI summary
A torque converter with a lockup clutch is provided with three oil passageways in and around the input shaft. One of the oil passageways provides oil to and from the converter for locking and unlocking the clutch via a piston. The piston moves away from the front cover of the torque converter to lock or apply the clutch and moves toward the front cover to release or unlock the clutch. A hydraulic circuit with control block is in fluid communication with the torque converter housing. The control block has three passages and two check valves to control fluid flow from the converter to the cooler, from the transmission to the cooler, and from the control block to the converter.