Dry Dual Clutch Interface Temperature Estimation
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Solution Overview
Problem
In dry dual clutch transmissions, accurately determining the temperature at the friction interfaces is challenging due to the difficulty in placing temperature sensors directly on the clutches, which can lead to permanent damage and reduced torque capacity if critical temperatures are exceeded.
Innovation Solution
A method is developed to determine interface temperatures by identifying slipping events, calculating heat flux, and using thermal models to estimate bulk and interface temperatures, allowing for control actions to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are placed directly on the clutch friction interfaces, then temperature measurement accuracy is improved, but the risk of permanent damage and torque capacity loss increases when critical temperatures are exceeded
Solution Approach 1:
The patent uses thermal coupling elements (temperature sensors embedded in the clutch housing or pressure plate) as intermediaries to indirectly measure friction interface temperatures. These sensors are positioned to thermally couple with the friction surfaces through conduction, allowing temperature estimation without direct contact with the high-stress friction interface, thus avoiding sensor damage while maintaining measurement capability
Solution Approach 2:
The patent replaces direct mechanical/physical sensor contact with a thermal modeling approach. By using thermal circuits and heat transfer models that simulate the thermal behavior of the clutch system, the actual temperature at the friction interface is calculated based on measurements from safer locations and known thermal properties, substituting direct measurement with computational estimation
2Reliability
If thermal models are used to estimate interface temperatures, then the risk of clutch damage is reduced, but the measurement precision and accuracy of temperature determination deteriorates
Solution Approach 1:
The patent employs multiple thermal modeling parameters including thermal conductivity, specific heat capacity, mass distribution, and heat generation rates to create a comprehensive thermal circuit model. By adjusting and optimizing these parameters based on experimental data and material properties, the model achieves sufficient accuracy for control purposes while maintaining system reliability
Solution Approach 2:
The patent implements a feedback mechanism where temperature sensor readings from the thermal model are continuously compared with actual measurements from embedded sensors. The model parameters are adjusted based on this feedback to improve accuracy over time, and the estimated temperatures are used to trigger control actions when threshold values are approached, creating a closed-loop system that balances accuracy with safety
3Ease of operation
If heat flux calculations are performed to determine interface temperatures, then temperature control capability is improved, but the computational complexity and processing requirements increase
Solution Approach 1:
The patent divides the clutch system into discrete thermal zones or nodes (e.g., friction surface, pressure plate, housing) and applies heat flux calculations only to critical interfaces where temperature control is most needed. This segmentation allows the system to focus computational resources on key temperature determination points rather than modeling the entire clutch assembly in detail, reducing overall computational complexity while maintaining control capability
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
This method effectively estimates clutch temperatures and torque capacity, preventing damage and ensuring safe operation by executing control actions based on calculated delta interface temperatures.
Implementation Method 1
determining that a slipping event is occurring at a friction interface of a clutch in the dry dual clutch mechanism, and determining a heat flux generated by the slipping event
Data Source
AI summary
A method for determining interface temperatures for a dry dual clutch mechanism includes determining that a slipping event is occurring at a friction interface of a clutch in the dry dual clutch mechanism, and determining a heat flux generated by the slipping event. The method includes determining a flux bulk temperature from the determined heat flux and determining a flux interface temperature from the determined heat flux. The flux interface temperature is the temperature at the friction interface during the slipping event. The method calculates a delta interface temperature by subtracting the flux interface temperature from the flux bulk temperature. The method executes a control action with the calculated delta interface temperature.