Lock-Up Clutch Engagement Control for Retarding Systems
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Solution Overview
Problem
Current retarding systems in work machines, such as wheel loaders, experience premature wear and energy absorption issues due to inadequate disengagement of the lock-up clutch during braking, leading to inefficient energy distribution and potential transmission component failure.
Innovation Solution
A method and system that detect a pedal tap to disengage the lock-up clutch of a torque converter, allowing the power source output shaft and transmission input shaft to rotate freely, thereby reducing retarding force reliance on braking devices and minimizing energy absorption by the transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the lock-up clutch remains locked during braking, then the transmission absorbs kinetic energy to assist machine retardation, but a significant amount of energy may be absorbed by the transmission components causing reduction of useful life
Solution Approach 1:
The system dynamically adjusts the lock-up clutch state based on operating conditions. During braking events, the controller detects the braking condition and automatically unlocks the lock-up clutch to prevent excessive energy absorption by transmission components, while maintaining locked state during normal operation for optimal efficiency.
Solution Approach 2:
The control system continuously monitors operating parameters and provides feedback to adjust lock-up clutch engagement. When braking is detected, the system responds by unlocking the clutch, and can re-engage it when appropriate conditions are met, creating a closed-loop control system that optimizes both efficiency and component protection.
2Reliability
If the lock-up clutch is unlocked during braking, then the braking devices cause majority of retarding force leading to premature wear from heat generation, but keeping the clutch locked causes excessive energy absorption by transmission components
Solution Approach 1:
The system dynamically manages the lock-up clutch state during braking events. By unlocking the clutch when braking is detected, the system shifts the retarding load from the transmission to the braking devices, preventing transmission component damage while managing brake wear through controlled engagement timing.
3Use of energy by moving object
If the lock-up clutch is locked during normal operation, then power source output shaft and transmission input shaft rotate at same speed improving efficiency, but during braking this causes excessive energy absorption by transmission
Solution Approach 1:
The system maintains the lock-up clutch in a locked state during normal operation to maximize power transmission efficiency by synchronizing the power source output shaft and transmission input shaft rotation. Upon detecting braking conditions, the system dynamically unlocks the clutch to redirect energy flow and prevent excessive energy absorption by transmission components.
Data Source
AI summary
A method for controlling an engagement of a lock-up clutch (LUC) of a torque converter of a machine is disclosed. The method includes detecting a pedal tap of a pedal, wherein the pedal tap is detected when the pedal is depressed from a position corresponding to a pedal displacement less than a first threshold displacement to a position corresponding to a pedal displacement greater than a second threshold displacement, and then released to a position corresponding to a pedal displacement less than the first threshold displacement within a threshold time duration. The method further includes causing the LUC to move to the LUC unlocked position if the pedal tap is detected.