Torque Control for Lock-Up Clutch Thermal Management
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Solution Overview
Problem
The increased output of prime movers leads to lock-up clutch temperatures exceeding allowable limits when engaged, causing reduced acceleration performance due to the clutch remaining disengaged to avoid overheating.
Innovation Solution
A target torque control device and method that reduces the prime mover's target torque when the lock-up clutch is engaged, ensuring the heat generation temperature remains within safe limits during up-shift transmissions, and executes this reduction only during torque phase changes to minimize driver discomfort and maintain acceleration performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output of the prime mover is increased, then the power output is improved, but the lock-up clutch temperature exceeds allowable limits when engaged
Solution Approach 1:
The control device dynamically adjusts the target torque of the prime mover based on the operational state of the lock-up clutch. When the clutch is engaged, the system reduces the target torque to prevent temperature exceedance, and restores it when the clutch is disengaged, creating a dynamic adaptation to operational conditions
Solution Approach 2:
The system changes the torque parameter of the prime mover based on the lock-up clutch engagement state. By modifying the target torque parameter dynamically, the system prevents overheating while maintaining high power output capability when conditions permit
2Temperature
If the lock-up clutch remains disengaged to avoid overheating, then the temperature is controlled within limits, but the acceleration performance deteriorates
Solution Approach 1:
The system dynamically switches between torque reduction and normal torque output based on lock-up clutch engagement detection. When the clutch is disengaged, full torque is available for acceleration; when engaged, torque is reduced to control temperature, optimizing both performance and thermal management
3Temperature
If the target torque is reduced when the lock-up clutch is engaged, then the lock-up clutch temperature is maintained within allowable limits, but the acceleration performance may be affected
Solution Approach 1:
The control device implements dynamic torque management by detecting lock-up clutch engagement state and adjusting target torque accordingly. This dynamic approach maintains temperature control during clutch engagement while preserving acceleration performance during disengagement
Solution Approach 2:
The system changes the target torque parameter based on the lock-up clutch state, reducing it during engagement to control temperature and restoring it during disengagement to maintain acceleration performance, optimizing both thermal and performance requirements
Data Source
AI summary
A target torque control device and a target torque control method capable of maintaining a temperature within an allowable temperature even when a lock-up clutch is engaged are provided. In a target torque control device (ECU) for setting a target torque of a prime mover (E) that outputs a torque to a multi-stage transmission (3) including a torque converter (2) and a lock-up clutch (2a), when the lock-up clutch (2a) is in an engaged state (STEP 1), a target torque reduction control for reducing a target torque of the prime mover (E) (STEP 3) is executed so that an output torque of the prime mover (E) becomes an output torque at which a heat generation temperature of the lock-up clutch (2a) does not exceed an allowable temperature during the up-shift transmission (STEP 2).