CVT Lock-Up Clutch Control to Cancel Drive Shaft Return Movement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Engagement of the lock-up clutch in existing transmission systems can cause vibrations, leading to discomfort for the driver.
Innovation Solution
A control device and method that includes a continuously variable transmission mechanism with a primary and secondary pulley, where the rotation speed of the secondary pulley increases as the torque transmission capacity of the lock-up clutch increases, followed by a gear shift process to change the gear ratio to cancel the return movement of the drive shaft twisted by the lock-up clutch engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the lock-up clutch is engaged to improve torque transmission efficiency, then power transmission efficiency is improved, but vibration occurs causing driver discomfort
Solution Approach 1:
The control device performs a gear shift process before complete engagement of the lock-up clutch to prevent vibration. By changing the gear ratio in advance, the system prepares the transmission mechanism to absorb or mitigate the shock and vibration that would otherwise occur during clutch engagement, thereby maintaining both efficiency and comfort.
2Object-affected harmful factors
If the gear ratio is changed to cancel drive shaft return movement, then vibration is reduced, but the control complexity increases
Solution Approach 1:
The control device monitors the engagement state of the lock-up clutch and the rotation speed of the secondary pulley, and automatically adjusts the gear ratio accordingly. This feedback-based control system detects when vibration is likely to occur and responds by changing the gear ratio to cancel drive shaft return movement, reducing vibration without requiring complex manual intervention.
3Object-affected harmful factors
If the lock-up clutch engagement is delayed to prevent vibration, then vibration is reduced, but the torque transmission efficiency decreases
Solution Approach 1:
Instead of delaying clutch engagement, the system performs a preliminary gear shift action before complete engagement. This preliminary adjustment of the gear ratio prepares the transmission to handle the engagement shock, allowing the clutch to engage promptly for efficient torque transmission while the pre-adjusted gear ratio prevents vibration.
Solution Approach 2:
The system dynamically adjusts the gear ratio based on the real-time engagement state of the lock-up clutch. By making the gear ratio changeable and adaptive rather than fixed, the system can optimize both torque transmission efficiency and vibration reduction at different stages of clutch engagement, achieving both goals simultaneously.
Data Source
AI summary
A controller for a transmission including a continuously variable transmission mechanism including a primary pulley to which power of an engine is input, a secondary pulley that transmits the power to a drive wheel, and a belt that is wound around the primary pulley and the secondary pulley, increases a rotation speed of the secondary pulley as a torque transmission capacity of a lock-up clutch of a torque converter provided between the engine and the primary pulley increases, and the lock-up clutch is engaged, performs a gear shift process to change a gear ratio of the continuously variable transmission mechanism to a high side or a low side so as to cancel return movement of a drive shaft which has been twisted by the engagement of the lock-up clutch.