Lockup Control Device Heat Accumulation Correction
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Solution Overview
Problem
Existing lockup control devices for vehicle power transmission systems with fluid transmission devices may restrict flex lockup control unnecessarily, potentially compromising the durability of friction members due to excessive heat generation, or fail to adequately protect them from deterioration.
Innovation Solution
A lockup control device with an electronic control unit that calculates and corrects the target differential rotation based on the heat accumulation amount, long-term change, and other factors like oxidative deterioration and foreign matter in the lubricating oil, to adjust the flex lockup control and protect friction members from excessive fatigue and thermal load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If flex lockup control is executed with a fixed target differential rotation, then the simplicity of control is maintained, but the friction members may deteriorate due to excessive heat generation
Solution Approach 1:
The target differential rotation is made dynamic rather than fixed. The electronic control unit adjusts the target differential rotation based on the cumulative heat accumulation amount, allowing the control parameter to adapt to changing thermal conditions and protect friction members from excessive heat while maintaining control simplicity
Solution Approach 2:
The control system changes the parameter (target differential rotation) based on thermal conditions. When the cumulative heat accumulation amount exceeds a threshold, the target differential rotation is reduced, thereby controlling heat generation and protecting friction members without complex structural modifications
2Reliability
If the target differential rotation is reduced to protect friction members, then heat generation is controlled, but flex lockup control is restricted beyond necessity
Solution Approach 1:
The system selectively changes the target differential rotation parameter only when necessary (when cumulative heat accumulation exceeds the threshold). This ensures friction member protection is activated only when heat-related deterioration risk exists, avoiding unnecessary restriction of flex lockup control during normal operating conditions
Solution Approach 2:
The control system uses feedback from the cumulative heat accumulation amount to dynamically adjust the target differential rotation. This feedback mechanism ensures that control restrictions are applied only when thermal conditions warrant protection, maintaining optimal flex lockup control performance under normal conditions
3Reliability
If existing heat-based control methods are used, then some protection is provided, but the control is not sufficient to prevent friction member deterioration
Solution Approach 1:
The control system uses readily available data (rotational speeds of input and output shafts, which are already measured for normal operation) to calculate the differential rotation and cumulative heat accumulation. This self-service approach avoids additional sensors or complex measurements, providing effective protection without proportionally increasing system complexity
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 protects friction members from heat-induced deterioration and improves durability without restricting flex lockup control, ensuring optimal performance and longevity of the vehicle's power transmission components.
Implementation Method 1
the heat generated may compromise durability
Data Source
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AI summary
Provided is a lockup control device and a lockup control method for a vehicle power transmission device (16) provided with a fluid transmission device (20) including a lockup clutch. The lockup clutch is controlled to perform slip-engagement such that a differential rotation between an input-side rotating member and an output-side rotating member of the fluid transmission device (20) is a target differential rotation set in advance, and the target differential rotation is corrected based on transition of a heat accumulation amount applied to friction members of the lockup clutch.