Friction Clutch Temperature Estimation for Torque Control
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Solution Overview
Problem
Existing power transmission devices with friction clutches face challenges in accurately estimating temperature without dedicated sensors, leading to inadequate thermal management due to simplified assumptions and generalizations in algorithms, which can result in damage from extreme temperatures.
Innovation Solution
A power transmission device with a controller that determines the current power state and thermal coefficients using a thermal coefficient model, allowing for an approximated temperature calculation of the friction clutch, enabling controlled operation of the actuator to manage heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated temperature sensor is mounted to the friction clutch to monitor temperature, then temperature measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an intermediary algorithm that uses readily available sensor data (torque, speed, power state) as proxies to infer clutch temperature. Instead of directly measuring temperature with a dedicated sensor, the system uses these intermediary parameters combined with thermal models to calculate an estimated temperature, thereby avoiding the need for additional hardware while maintaining adequate measurement capability
Solution Approach 2:
The patent creates a virtual copy of the temperature measurement function through computational modeling. Rather than physically measuring temperature, the system replicates the temperature information through algorithms that simulate thermal behavior based on operational parameters, providing a software-based alternative to hardware sensing
2Device complexity
If simplified algorithms with generalizations are used to estimate temperature, then device complexity is reduced, but temperature estimation accuracy deteriorates
Solution Approach 1:
The patent implements dynamic temperature estimation by continuously updating the thermal model based on real-time power state changes and operational conditions. The algorithm adapts to varying clutch conditions (engaged, disengaged, slipping) and adjusts calculations accordingly, allowing accurate temperature estimation across different operating scenarios without requiring complex fixed-model approaches
Solution Approach 2:
The patent changes the parameters used for temperature estimation by incorporating multiple operational variables (torque, speed, power state, thermal coefficients) rather than relying on single-parameter or overly simplified models. The system dynamically adjusts thermal coefficients based on clutch condition, enabling accurate temperature estimation across diverse operating conditions while maintaining algorithmic simplicity
3Power
If the actuator applies more force to the clutch pack to transmit torque, then power transmission capacity is improved, but heat generation increases
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors estimated clutch temperature and adjusts actuator force application accordingly. When temperature exceeds thresholds, the system reduces actuator force to allow cooling, creating a closed-loop control that balances power transmission needs with thermal management, preventing overheating while maintaining adequate torque capacity
Solution Approach 2:
The patent employs periodic modulation of actuator engagement to manage thermal buildup. By cycling between engagement and disengagement states based on temperature conditions, the system allows periodic cooling intervals while maintaining overall power transmission capability, preventing continuous heat accumulation that would occur with sustained high-force engagement
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 solution provides accurate temperature estimation and effective thermal management, preventing damage to the friction clutch by adjusting torque transmission based on calculated temperatures, enhancing efficiency and reducing costs by eliminating the need for dedicated temperature sensors.
Implementation Method 1
one set of the plates will rotate relative to the other set of plates, which can generate significant heat given the magnitude of the friction between adjacent plates
Implementation Method 2
An actuator is employed to exert a compressive force on the clutch pack to frictionally engage the two sets of plates to one another to thereby resist relative rotation
Implementation Method 3
The amount of torque that is capable of being transmitted through the friction clutch is generally proportional to the magnitude of the compressive force that is exerted by the actuator
Data Source
AI summary
A power transmission device includes a friction clutch, an actuator, and a controller configured to determine an approximated temperature change of the friction clutch. The controller is configured to determine a current power state of the friction clutch, determine a desired power state change based on the current power state and a previous power state, determine a plurality of thermal coefficients based on a thermal coefficient model, the desired power state change, and a set of operation variables, determine an approximated temperature change of the friction clutch based on the thermal coefficients and a friction clutch temperature model, determine an approximated clutch temperature based on the approximated temperature change and a contemporaneous value of an device ambient temperature, and control operation of the actuator based at least on the approximated clutch temperature.