Semi-Automatic Transmission Reverse Gear Control Logic
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Solution Overview
Problem
Current semi-automatic transmissions do not allow drivers to select a reverse gear using the shifter, which increases complexity and risks damage to the transmission or engine components, and there is a need for a method to control the transmission to prevent accidental selection of reverse gear.
Innovation Solution
A semi-automatic transmission system with a control unit that prevents the selection of reverse gear unless the reverse actuator is actuated simultaneously with the shifter, incorporating engine speed and vehicle speed sensors to ensure safe operation, and a shifter arrangement that requires separate hand operation of the actuator and shifter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the shifter is used to select reverse gear in semi-automatic transmission, then the device complexity is reduced, but the risk of damaging the transmission or engine components increases
Solution Approach 1:
A separate reverse actuator is introduced as an intermediary component between the driver's intent to select reverse gear and the transmission system. This actuator works in conjunction with the shifter to enable reverse gear selection, thereby maintaining simplicity while adding a safety layer to prevent accidental reverse gear engagement that could damage the transmission or engine components.
2Reliability
If a separate reverse system is used, then the transmission reliability is improved, but the device complexity increases
Solution Approach 1:
The reverse actuator is integrated with the existing shifter mechanism rather than being a completely separate system. The control unit combines signals from both the shifter and the reverse actuator to determine when to engage reverse gear, merging multiple control inputs into a unified decision-making process that reduces overall system complexity while maintaining safety.
3Reliability
If the reverse actuator requires simultaneous operation with the shifter, then the transmission safety is improved, but the ease of operation decreases
Solution Approach 1:
The system requires the driver to perform preliminary actions in a specific sequence: first move the shifter to the reverse position, then actuate the reverse actuator. This preliminary action sequence ensures intentional reverse gear selection while maintaining operational simplicity through clear, step-by-step controls that are easy to learn and execute.
Data Source
AI summary
A vehicle (1) having a frame, at least two wheels (14, 16), a straddle seat (28), a handlebar (18) with first (20) and second (22) handles, an engine (30), and a semi-automatic transmission (32). A reverse actuator (152) is electronically connected to a control unit (46) of the semi-automatic transmission. At least one shifter (108) is electronically connected to the control unit such that moving the at least one shifter to an up-shift position causes the control unit to send a signal to the semi-automatic transmission to shift up and moving the at least one shifter to the down-shift position causes the control unit to send a signal to the semi-automatic transmission to shift down. The control unit sends a signal to the semi-automatic transmission to select the at least one reverse gear (34) only when the reverse actuator is actuated while the at least one shifter is moved. A method of controlling a semi-automatic transmission is also disclosed.