Lock-Up Control Valve Circuit for Smooth Torque Converter Engagement
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Solution Overview
Problem
Existing hydraulic circuits for torque converters with three hydraulic paths lack sufficient controllability of the lock-up device, particularly in switching between engaged and released states.
Innovation Solution
A hydraulic circuit design incorporating a torque converter control valve and a lock-up control valve with a displaceable valve body, actuator, urging member, and strategically positioned ports to control oil flow, allowing precise regulation of hydraulic pressure for improved lock-up device controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hydraulic circuit with three hydraulic paths is used, then the structure is simple, but the controllability of the lock-up device is insufficient
Solution Approach 1:
The hydraulic circuit is segmented into three independent hydraulic paths, each controlled by a separate control valve (first control valve, second control valve, and third control valve). This segmentation allows independent control of each hydraulic path, thereby improving the controllability of the lock-up device without requiring a completely new complex system architecture.
Solution Approach 2:
The control valves are designed with multiple ports and passages that can handle multiple hydraulic functions simultaneously. Each control valve can regulate pressure, control flow direction, and manage multiple hydraulic paths through its internal passage structure, providing multi-functionality that improves controllability without proportionally increasing overall system complexity.
2Force
If hydraulic pressure is increased to improve lock-up engagement, then engagement force is improved, but sudden pressure changes cause instability
Solution Approach 1:
The control valves are configured to pre-regulate hydraulic pressure before it reaches the lock-up device. By controlling the pressure buildup in advance through regulated flow passages and pressure control mechanisms, the system achieves smooth engagement without sudden pressure spikes, thereby maintaining both engagement force and pressure stability.
Solution Approach 2:
The control valves act as intermediary devices between the hydraulic pump and the lock-up device. These intermediaries regulate and buffer hydraulic pressure fluctuations, providing stable controlled pressure to the lock-up device while preventing sudden pressure changes from propagating through the system, thus maintaining both force and stability.
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
Enhances the controllability of the lock-up device by stabilizing hydraulic pressure and preventing sudden changes, ensuring smooth transitions between engaged and released states.
Implementation Method 1
an urging member that causes the valve body to displace toward a second valve position on the other side in the axial direction
Implementation Method 2
oil flowing in from the third port urges the valve body toward the second valve position
Data Source
AI summary
A hydraulic circuit including: a torque converter control valve, and a lock-up control valve, in which the lock-up control valve includes a valve body that is displaceable in an axial direction, an actuator that causes the valve body to displace toward a first valve position on one side in the axial direction, an urging member that causes the valve body to displace toward a second valve position on the other side in the axial direction, a first port to which oil having a line pressure as a source pressure is supplied, a second port that communicates with a first oil passage connected to the piston oil chamber, a third port that communicates with the first oil passage, and a drain port, the valve body is displaceable between the first valve position and the second valve position, the first valve position allowing the first port and the second port to communicate with each other, the second valve position allowing the second port and the drain port to communicate with each other, and oil flowing in from the third port urges the valve body toward the second valve position.