DCT Clutch Overheating Control via Gear Shifting
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Solution Overview
Problem
Dual Clutch Transmissions (DCTs) using dry clutches are prone to overheating, especially when drivers repeatedly stop and start their vehicles in the first gear on gentle slopes, as there is no cooling mechanism and heat is concentrated on the odd-numbered gears, leading to potential clutch failure.
Innovation Solution
A control method that senses the engaged gear, road inclination, and vehicle speed to adjust the shifting pattern by directly shifting into the second gear when the odd-numbered clutch temperature exceeds a set threshold, and increases engine torque to distribute heat to the even-numbered clutch, thereby preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the vehicle repeatedly stops and starts in the first gear on a gentle slope, then the vehicle can maintain good roadability and climbing performance, but the odd-numbered clutch overheats due to concentrated heat generation
Solution Approach 1:
The transmission system is segmented into two independent clutch systems (odd-numbered clutch for 1st/3rd/5th gear and even-numbered clutch for 2nd/4th/6th gear). When the odd-numbered clutch temperature exceeds the threshold, the controller switches to using the even-numbered clutch for gear engagement, effectively segmenting the heat generation problem and allowing the odd-numbered clutch to cool down while maintaining vehicle operation.
Solution Approach 2:
The controller implements periodic switching between odd-numbered and even-numbered clutches based on temperature monitoring. When the odd-numbered clutch temperature exceeds the threshold, the system periodically shifts to even-numbered gear engagement, creating a cyclic pattern of heat generation and cooling that prevents sustained overheating while maintaining roadability.
2Power
If the clutch slips to transmit torque by friction, then torque transmission is achieved, but thermal energy is generated causing heat concentration and potential overheating
Solution Approach 1:
The controller acts as an intermediary that monitors clutch temperature and intervenes by switching between odd-numbered and even-numbered clutches. When the odd-numbered clutch temperature exceeds the threshold, the controller mediates the torque transmission process by engaging the even-numbered clutch, thereby preventing excessive heat generation while maintaining power transmission capability.
Solution Approach 2:
The system changes the operational parameters of the transmission system by switching between different clutch engagement patterns based on temperature conditions. When the odd-numbered clutch temperature exceeds the threshold, the controller changes the gear engagement parameters to use the even-numbered clutch, thereby altering the heat generation pattern and preventing overheating while maintaining torque transmission.
3Temperature
If the shifting pattern is adjusted to shift into the second gear to cool the odd-numbered clutch, then clutch temperature is reduced, but the up-shifting pattern is lowered compared to the previous pattern
Solution Approach 1:
The shifting pattern is made dynamic and adaptive based on real-time clutch temperature conditions. The controller continuously monitors the odd-numbered clutch temperature and dynamically adjusts the shifting pattern accordingly. When the temperature exceeds the threshold, the system dynamically switches to a pattern that engages the even-numbered clutch (second gear), and when the temperature is acceptable, it returns to the reference shifting pattern, creating a flexible and adaptive transmission control system.
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 reduces or prevents overheating of the odd-numbered clutch, enhancing the durability of the transmission by distributing heat and maintaining vehicle roadability.
Implementation Method 1
a loss of torque generated by the clutch slipping while power is transmitted by friction of the friction material of a disc is converted into thermal energy and generates heat
Data Source
AI summary
A control method for a vehicle with a DCT may include: a sensing step in which a controller senses a currently engaged gear of the vehicle, an inclination of a road, and a vehicle speed; a comparing step in which the controller compares a temperature of an odd-numbered clutch of the transmission with a set temperature when the currently engaged gear is a first gear, the inclination of the road is within a set range, and the vehicle speed is a set vehicle speed or less, after the sensing step; and an adjusting step in which the controller adjusts a shifting pattern to shift into a second gear when the temperature of the odd-numbered clutch is the set temperature or more, as the result of the comparing step.