CVT Shift Line Control for Re-Acceleration Intent Detection
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Solution Overview
Problem
Existing control devices for continuously variable transmissions fail to accurately detect a driver's intention to accelerate, leading to 'rubber band feel' during increased accelerator pedal opening, where engine rotation speed increases without corresponding vehicle acceleration, causing a sense of incongruity.
Innovation Solution
A control device and method that switches to a linear mode based on predetermined acceleration conditions, updating the acceleration start vehicle speed and generating new shift lines to match driver intent, using a microcomputer and sensors to manage speed ratios and prevent excessive input rotation speed increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the accelerator pedal opening is increased during acceleration, then the driver intends to accelerate further, but the existing control device fails to detect this re-acceleration intention, causing rubber band feel
Solution Approach 1:
The control device continuously monitors accelerator pedal opening changes and provides feedback by detecting re-acceleration intentions. When the accelerator pedal opening increases by a predetermined amount or more during acceleration, the system detects this as a re-acceleration intention and updates the acceleration start vehicle speed accordingly, preventing rubber band feel.
2Stability of the object's composition
If the acceleration start vehicle speed is not updated during re-acceleration, then the shift line is based on outdated speed data, but this causes rubber band feel where engine rotation speed increases without corresponding vehicle acceleration
Solution Approach 1:
The control device dynamically updates the acceleration start vehicle speed based on detected re-acceleration intentions. When re-acceleration is detected through accelerator pedal opening changes, the system updates the acceleration start vehicle speed to the current vehicle speed, allowing the shift line to adapt dynamically to changing acceleration conditions and maintain proper alignment between engine speed and vehicle acceleration.
3Device complexity
If the control device uses fixed acceleration start vehicle speed, then the control logic is simple, but it cannot accurately detect re-acceleration intentions during multi-stage acceleration
Solution Approach 1:
The control device performs preliminary detection of accelerator pedal opening changes during acceleration. By monitoring whether the accelerator pedal opening has increased by a predetermined amount or more, the system proactively identifies re-acceleration intentions before they result in rubber band feel, and updates the acceleration start vehicle speed in advance.
Data Source
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AI summary
A control device for continuously variable transmission includes an operating state detection means for detecting an operating state of a vehicle including a vehicle speed and an accelerator pedal opening, a control means for controlling a speed ratio of a continuously variable transmission based on the operating state, an acceleration request determination means for determining the presence or absence of an acceleration request of a driver based on the accelerator pedal opening, and a speed ratio setting means for setting a speed reduction ratio controlled by the control means to be smaller with an increase in an acceleration start vehicle speed if the accelerator pedal opening is equal during acceleration. The control means updates the acceleration start vehicle speed to a vehicle speed at the time of a determination after determining that the accelerator pedal opening has been increased during acceleration.