CVT Intermediate Gear Ratio Selection for Manual Mode Precision
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Solution Overview
Problem
Existing continuously variable transmissions with manual modes often fail to select a suitable gear ratio, as the amount of gear ratio change is insufficient when shifting to a next gear or excessive when shifting to the second next gear, leading to improper acceleration and braking performance.
Innovation Solution
A continuously variable transmission system that allows for a second gear-change operation to select an intermediate gear ratio between the next and second next gear, using a gear-change operating section with switches and sensors to detect and control the gear-change operations, ensuring proper detection and execution of gear changes based on operational force, speed, and duration, thereby allowing for more precise gear ratio selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gear ratios corresponding to approximately five to seven gears are previously set and a gear ratio is successively changed to a gear ratio corresponding to a next gear in accordance with upshift and downshift operations, then the transmission provides a manual mode with discrete gear options, but a suitable gear ratio cannot always be properly set in accordance with various travel states
Solution Approach 1:
The patent introduces dynamic gear ratio selection between fixed gear ratios. When a downshift operation is detected, the system can select an intermediate gear ratio between the current gear ratio and the next lower gear ratio, rather than being restricted to discrete fixed gear ratios. This dynamic adjustment capability allows the transmission to adapt continuously to varying travel conditions while maintaining the simplicity of manual operation.
Solution Approach 2:
The system changes the gear ratio parameter dynamically based on operational context. Instead of switching between fixed discrete gear ratios, the control section can select any gear ratio within a range between the current gear ratio and the target gear ratio, effectively changing the gear ratio parameter continuously to match travel conditions.
2Speed
If downshifting is performed for increasing the rotation speed of the engine, then the rotation speed of the engine increases, but the rotation speed of the engine may not be sufficiently increased by downshifting by only one gear or may become too high by downshifting by two gears
Solution Approach 1:
The system enables dynamic engine speed control through intermediate gear ratio selection. When downshifting is required to increase engine rotation speed, the control section can select an intermediate gear ratio between the current gear ratio and the next lower gear ratio, providing fine-grained control over engine speed adjustment rather than abrupt transitions between fixed gear ratios.
Solution Approach 2:
The gear ratio parameter is adjusted dynamically to achieve precise engine speed control. The control section calculates the appropriate intermediate gear ratio based on the desired engine speed range, allowing continuous parameter adjustment between discrete gear ratios to match the driver's acceleration needs.
3Loss of energy
If a gear ratio is automatically set in accordance with a request for a torque from a driver or a travel state of a vehicle, then the transmission optimizes fuel consumption, but the driver cannot manually select a specific gear ratio for specific driving conditions
Solution Approach 1:
The transmission system combines both automatic and manual control functions in a unified system. The same control section that performs automatic gear ratio selection based on torque requests and travel states also enables manual gear ratio selection with intermediate ratios, making the system universally adaptable to both automated optimization and manual driver control scenarios.
Solution Approach 2:
The system provides self-service by automatically selecting optimal gear ratios based on sensor inputs when the driver does not intervene, while simultaneously allowing manual override when the driver desires specific gear ratios for particular driving conditions. The system serves both automated optimization and manual control needs.
Data Source
AI summary
A continuously variable transmission includes a continuous gear-change mechanism, a gear-change operating section to which a gear-change operation is input, and a gear-change controlling section changing a gear ratio of the mechanism according to the gear-change operation that is input from the operating section. A first gear-change operation and a second gear-change operation, performed subsequently to the first operation, or an input from a second gear-change operating section can be input to the operating section. The e controlling section is provided with the plural gear ratios for plural gears and previously set, causes the mechanism to perform, according to the first operation, a gear-change operation to a gear ratio for a next gear, and to perform, according to the second operation, a gear-change operation to an intermediate gear ratio set between the gear ratio for the next gear and a gear ratio for a second next gear.