Clutch Touch Point Learning via Rotational Speed Ratio
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Solution Overview
Problem
Current methods for learning the touch point of a clutch in dual-clutch transmissions are prone to control errors and cannot accurately determine the touch point while the vehicle is being driven, especially due to variations in temperature and abrasion.
Innovation Solution
A method and apparatus that calculate a reference value by dividing the difference in rotational speeds between the drive shaft clutch and non-drive shaft clutch by the engine's rotational speed, and output control signals to move the non-drive shaft clutch toward the engine until a preset threshold is reached, determining the touch point at this point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional touch point learning methods are used, then the clutch control error is reduced, but the method cannot learn the touch point while the vehicle is being driven and is prone to control errors due to temperature change or abrasion
Solution Approach 1:
The patent implements a dynamic touch point learning method that adapts to real-time operating conditions. The control unit continuously monitors rotational speeds of the engine, drive shaft clutch, and non-drive shaft clutch during vehicle operation, and dynamically adjusts the learning process based on calculated reference values. This allows the system to learn and update touch point positions while the vehicle is being driven, rather than requiring static pre-learning only.
Solution Approach 2:
The patent employs a feedback mechanism where the control unit calculates a reference value by comparing the rotational speed difference between the drive shaft clutch and non-drive shaft clutch against the engine's rotational speed. This reference value provides continuous feedback to determine when the non-drive shaft clutch reaches the touch point position, enabling accurate touch point learning during actual vehicle operation and improving both measurement precision and adaptability.
2Measurement precision
If the non-drive shaft clutch is moved toward the engine to learn the touch point, then the touch point position can be determined, but control errors occur due to variations in temperature and abrasion
Solution Approach 1:
The patent addresses reliability issues by continuously monitoring and comparing rotational speed parameters under varying operating conditions. The control unit calculates a reference value that accounts for temperature changes and abrasion by comparing the ratio of rotational speed differences. This parameter-based approach allows the system to adapt to changing physical conditions while maintaining accurate touch point determination.
3Device complexity
If a simple touch point learning method is used, then the device complexity is low, but the control error cannot be significantly reduced
Solution Approach 1:
The patent achieves high measurement precision without increasing device complexity by making the existing control unit perform multiple functions. The control unit not only controls clutch operation but also calculates reference values, monitors rotational speeds, determines touch point positions, and adapts to varying operating conditions. This multi-functional approach eliminates the need for separate learning devices while significantly improving touch point learning accuracy.
Data Source
AI summary
A method for learning a touch point of a clutch may include a step of outputting a first control signal for controlling a touch point learning mode to be entered if a preset condition is satisfied, a step of calculating a reference value by dividing a difference value between rotational speed of a drive shaft clutch and rotational speed of a non-drive shaft clutch by a difference value between rotational speed of an engine and the rotational speed of the drive shaft clutch, a step of outputting a second control signal for moving the non-drive shaft clutch toward the engine if the reference value is less than a preset threshold value and a step of determining a position of the non-drive shaft clutch at a time when the reference value reaches the preset threshold value to be the touch point.