CVT Control Device for Straddle-Type Vehicle Kick Down
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In continuously variable transmissions (CVTs) used in straddle-type vehicles, unnecessary engine racing occurs during re-acceleration after deceleration, leading to unsmooth acceleration feelings.
Innovation Solution
A CVT system with a control device that sets a control target value for a kick down mode, limiting the speed change ratio to prevent engine racing, and adjusting the target value based on throttle operation to ensure smooth acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If kick down mode is used during re-acceleration after deceleration, then acceleration response is improved, but unnecessary engine racing occurs causing unsmooth acceleration
Solution Approach 1:
The control device changes the control target value parameters based on the throttle operation state. When the throttle is fully closed and then opened for re-acceleration, the system applies a specific limit value (fifth limit value) that prevents the control target value from exceeding certain thresholds, thereby controlling the speed change ratio to avoid engine racing while maintaining acceleration response
Solution Approach 2:
The control device continuously monitors the throttle operation state and adjusts the control target value accordingly. By detecting whether the throttle is fully closed and subsequently opened, the system provides feedback control that applies appropriate speed change ratio limits during re-acceleration, preventing engine racing while maintaining smooth acceleration
2Stability of the object's composition
If speed change ratio is controlled to prevent engine racing, then acceleration smoothness is improved, but acceleration response may be delayed
Solution Approach 1:
The system uses different limit values for control target values based on throttle operation state. During re-acceleration after full throttle closure, the fifth limit value is applied which allows sufficient acceleration response while preventing excessive speed change ratio changes that would cause engine racing. The limit values are specifically calibrated to balance smoothness and response
Data Source
AI summary
When performing kick down, during re-acceleration after decelerating, the engine sometimes races unnecessarily, and a smooth acceleration feeling is not obtained. During control by a kick down mode, when accelerating after a throttle has been fully closed, a control target value is set so as not to pass to a Low side of a limit value of the control target value used during re-acceleration. As a result, racing of the engine is inhibited.