Straddle Vehicle ECVT Shift Down Control
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Solution Overview
Problem
Conventional electronically controlled continuously variable transmissions (ECVTs) in vehicles do not allow riders to easily perform intentional shift down operations in AT mode, making it difficult to activate engine brakes strongly or achieve quick acceleration, as they require complex mode changes between AT and MT modes.
Innovation Solution
A control system for a straddle type vehicle with a mode temporarily changing switch that allows the gear ratio to be changed to a lower gear ratio within the MT mode with a single operation, enabling easy shift down operations and automatic return to AT mode when conditions are met, simplifying the process of accelerating or decelerating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional ECVT with AT and MT modes is used, then the gear ratio can be automatically changed in AT mode, but the rider cannot easily perform intentional shift down operations
Solution Approach 1:
The system dynamically switches between AT mode and MT mode based on rider input. When the shift down switch is operated in AT mode, the system temporarily transitions to MT mode to enable the shift down operation, then automatically returns to AT mode. This dynamic mode adjustment allows the rider to perform shift down operations without manually changing modes, resolving the contradiction between ease of operation and device complexity.
Solution Approach 2:
The system performs automatic mode switching and automatic return to AT mode after the shift down operation. The control unit detects the shift down switch operation, automatically transitions to MT mode, executes the shift down, and then automatically returns to AT mode without requiring rider intervention. This self-service mechanism eliminates the need for complex manual mode switching operations.
2Productivity
If the rider manually switches from AT to MT mode to perform shift down operation, then the shift down can be executed, but the operation becomes complicated and troublesome
Solution Approach 1:
The system prepares for the shift down operation by automatically transitioning to MT mode when the shift down switch is operated in AT mode. This preliminary action of automatic mode switching eliminates the time the rider would otherwise spend manually switching modes, allowing the shift down operation to be executed quickly and efficiently.
Solution Approach 2:
The system maintains continuous operation by automatically returning to AT mode after the shift down is completed. This ensures that the transmission system remains in the appropriate mode for normal driving conditions without interruption, eliminating the loss of time associated with manual mode switching and maintaining the continuity of useful action.
Data Source
AI summary
A control system for an electronically controlled continuously variable transmission of a straddle type vehicle in which an intentional shift down operation is easily made in an AT mode. An MT mode temporarily selecting section makes the gear change mode selecting section select the MT mode temporarily and makes the gear ratio control section change the gear ratio of the transmission to a gear ratio from among a plurality of predetermined gear ratios that is positioned lower than a current gear ratio when a mode change signal is inputted in AT mode. An AT mode returning section returns the gear change mode selected by the gear change mode selecting section to AT mode when a release signal is outputted after MT mode is temporarily selected by the MT mode temporarily selecting section.