CVT Transmission Control Device Mode Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicles with internal combustion engines, especially those slow in torque response, there is a challenge in controlling acceleration due to delayed driving force increase in stepless transmission mode, leading to driver discomfort and difficulty in operating the accelerator.
Innovation Solution
A transmission control device that switches between stepless and stepped transmission modes based on actual accelerator opening, using a controller to determine the appropriate mode switch by setting threshold values that increase with vehicle speed, thereby reducing driver incongruity and optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If stepless transmission mode is used to continuously change transmission gear ratio, then fuel efficiency is improved, but driver's sense of incongruity increases due to delayed driving force increase
Solution Approach 1:
The system dynamically switches between stepless and stepped transmission modes based on accelerator opening degree and vehicle speed. The controller determines switching timing by comparing accelerator opening degree against threshold values that vary with vehicle speed, enabling the transmission system to adapt its characteristics to driving conditions and reduce driver incongruity while maintaining fuel efficiency
Solution Approach 2:
The invention changes the transmission control parameters by switching between continuous gear ratio adjustment (stepless mode) and discrete gear stage selection (stepped mode). The threshold values for mode switching are set to increase stepwise with vehicle speed, allowing the system to optimize the balance between fuel efficiency and driving force response characteristics
2Force
If down-shift is executed in stepless transmission mode to respond to accelerator operation, then driving force increase is achieved, but response time is delayed
Solution Approach 1:
The system performs preliminary action by pre-setting multiple threshold values that increase stepwise with vehicle speed. When accelerator opening degree reaches these predetermined thresholds, the controller proactively switches to stepped transmission mode, which provides more immediate and pronounced driving force increase compared to continuous stepless adjustment
3Force
If stepped transmission mode is used to provide fixed gear stages, then driving force response is improved, but fuel efficiency deteriorates
Solution Approach 1:
The system dynamically selects between stepped and stepless transmission modes based on real-time driving conditions. The controller monitors accelerator opening degree and vehicle speed, switching to stepped mode when rapid driving force response is needed and returning to stepless mode for fuel-efficient cruising, thereby optimizing the trade-off between driving force response and fuel efficiency
Data Source
AI summary
A transmission control device controls a CVT installed in a vehicle. The device has, as modes for the CVT, a CVT mode M1 for changing a transmission gear ratio steplessly based on the operating state of the vehicle, and a stepped transmission mode M2 for changing the transmission gear ratio stepwise based on the operating state of the vehicle. The device includes a transmission mode switching control unit (controller) 12 for controlling switching between the CVT mode M1 and the stepped transmission mode M2 based on an actual accelerator opening. The transmission mode switching control unit (controller) 12 performs switching from the CVT mode M1 to the stepped transmission mode M2, if the actual accelerator opening reaches or exceeds a first threshold value T1 set in a plurality of stages so as to increase stepwise in accordance with an increase in a vehicle speed.