CVT Control Device Second-Time Kick-Down Upshift Conditions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In continuously variable transmissions, second-time kick-down control combined with multistage-like kick-down control can result in acceleration failure and a reduced engine rotational speed, leading to an uncomfortable driving experience due to unintended acceleration termination.
Innovation Solution
A control device for continuously variable transmissions that includes an upshift determining unit, a second-time kick-down determining unit, and a second-time kick-down upshift conditions setting unit, which adjusts the upshift conditions to maintain a higher primary pulley rotational speed during second-time kick-down, ensuring sustained acceleration by using the second-time kick-down upshift conditions instead of normal upshift conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If second-time kick-down control is combined with multistage-like kick-down control, then downshift amount is increased to achieve faster acceleration, but upshift may be executed immediately after downshift causing acceleration failure and reduced engine rotational speed
Solution Approach 1:
The patent applies dynamics by making the upshift determination threshold adaptive rather than fixed. The upshift determining unit dynamically adjusts the primary rotational speed threshold based on whether second-time kick-down control is active. When second-time kick-down is detected, the system uses a higher threshold (second-time kick-down upshift conditions) instead of the normal threshold, allowing the system to maintain aggressive downshift behavior while preventing premature upshift execution that would terminate acceleration.
Solution Approach 2:
The patent changes the parameter of upshift determination by introducing different upshift conditions based on the kick-down state. The second-time kick-down upshift conditions setting unit modifies the primary rotational speed threshold parameter specifically for second-time kick-down scenarios. This parameter change ensures that upshift is delayed until appropriate conditions are met, preventing acceleration failure while maintaining the intended acceleration performance.
2Ease of operation
If normal upshift conditions are used during second-time kick-down control, then upshift is executed at standard primary rotational speed, but acceleration intention is not maintained and driver feels uncomfortable
Solution Approach 1:
The patent applies local quality by providing different upshift conditions for different operational states. Instead of using a single uniform upshift threshold for all conditions, the system implements specialized upshift conditions specifically for second-time kick-down scenarios. The second-time kick-down upshift conditions setting unit creates localized upshift logic that accounts for the specific acceleration intentions and operational context of second-time kick-down, ensuring driver intention is fulfilled while maintaining appropriate engine rotational speed.
Data Source
AI summary
A control device for a continuously variable transmission performs kick-down control for executing downshift if kick-down conditions are satisfied. The device includes an upshift determining unit, an upshift controller, a second-time kick-down determining unit, a second-time kick-down controller, and a second-time kick-down upshift conditions setting unit. The upshift determining unit determines whether upshift conditions are satisfied during kick-down control. The upshift controller sets an upshift amount and executes upshift if the upshift conditions are satisfied. The second-time kick-down determining unit determines whether second-time kick-down conditions are satisfied during kick-down control. The second-time kick-down controller sets a second-time kick-down downshift amount and executes downshift if the second-time kick-down conditions are satisfied. The second-time kick-down upshift conditions setting unit sets second-time kick-down upshift conditions if the second-time kick-down conditions are satisfied. If the second-time kick-down conditions are satisfied, the upshift determining unit performs determination using the second-time kick-down upshift conditions.