CVT Advance Compensation for Vibration Damping
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Solution Overview
Problem
Existing continuously variable transmission systems face challenges in achieving sufficient damping effects while maintaining stability of the speed ratio control system, particularly due to variations in vehicle operation states, which can lead to instability if the advance compensation amount is too large or insufficient.
Innovation Solution
A control method for continuously variable transmissions that adjusts the advance compensation amount based on the vibration frequency of the input shaft and the vehicle's operation state, ensuring stability and optimal damping effects by varying the advance amount according to parameters like rotation speed, input torque, speed ratio, secondary pressure, and oil temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the advance compensation amount is increased to suppress longitudinal vibrations, then the damping effect is improved, but the stability of the speed ratio control system deteriorates
Solution Approach 1:
The patent applies dynamics by making the advance compensation amount variable rather than fixed. The control device dynamically adjusts the advance compensation amount based on detected vibration frequency and vehicle operation state, allowing the system to optimize damping effectiveness while preventing instability across different operating conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the advance compensation amount according to detected vibration frequency and operation state parameters. When vibration frequency matches the resonant frequency of longitudinal vibration, the advance compensation amount is increased to enhance damping; otherwise, it is reduced to maintain control system stability.
2Device complexity
If the advance compensation amount is fixed at peak value frequency to simplify control, then the device complexity is reduced, but the damping effect becomes insufficient under varying operation states
Solution Approach 1:
The system transitions from a static fixed advance compensation approach to a dynamic adaptive approach. The control device continuously monitors vibration frequency and operation state, adjusting the advance compensation amount in real-time to maintain optimal damping performance across varying vehicle conditions without requiring complex additional hardware.
Solution Approach 2:
The patent implements feedback control by detecting the vibration frequency of the input shaft and using this information to adjust the advance compensation amount. The control device receives feedback on the actual vibration state and modifies the compensation parameter accordingly, creating a closed-loop system that adapts to changing operating conditions.
Data Source
AI summary
A control method of a continuously variable transmission mounted on a vehicle includes performing advance compensation in a speed ratio control system of the continuously variable transmission, and making an advance amount according to a vibration frequency of torsional vibration of an input shaft of the continuously variable transmission which is the advance amount of the advance compensation variable in accordance with an operation state of the vehicle. A feedback gain of speed ratio control of the continuously variable transmission performed in the speed ratio control system is variable in accordance with an operation state of the vehicle. When the advance amount is made variable, the advance amount is made variable in accordance with the feedback gain.