Shift Control System Sensor Cross-Validation
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Solution Overview
Problem
Existing shift control systems for saddle-type vehicles, such as motorcycles, face issues with unnecessary engine output control due to breakdowns in gearshift or gear position sensors during clutchless shifting operations, leading to driver discomfort.
Innovation Solution
A shift control system comprising a gear shift lever, gearshift sensor, shift cam, gear position sensor, and a control device that determines abnormality occurrence based on detection results from both sensors, stopping engine operation control when a breakdown is detected to prevent unnecessary engine output adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor (gearshift sensor or gear position sensor) is used to detect shifting operations, then the device complexity is reduced, but the reliability of shifting detection deteriorates due to inability to detect sensor breakdowns
Solution Approach 1:
The patent combines two different sensing methods (gearshift sensor detecting lever operation and gear position sensor detecting shift cam position) into a unified shifting detection system. By merging these independent detection paths, the system achieves cross-validation capability where each sensor can verify the other's readings, thereby improving reliability without significantly increasing overall system complexity.
Solution Approach 2:
The control device continuously compares detection results from both sensors and provides feedback to determine sensor abnormality. When the gearshift sensor detects a shifting operation but the gear position sensor does not detect corresponding shift cam rotation (or vice versa), the system identifies this discrepancy as abnormality feedback, triggering appropriate error handling to prevent incorrect engine output control.
2Reliability
If sensor breakdown detection is implemented using multiple sensors, then the reliability of shifting detection is improved, but the device complexity increases
Solution Approach 1:
Each sensor serves multiple functions: the gearshift sensor detects both normal shifting operations and abnormal conditions, while the gear position sensor similarly detects both normal shift cam rotation and abnormal states. This multi-functionality allows the system to use existing sensors for dual purposes (normal operation detection and breakdown detection) without adding dedicated failure detection sensors, thereby improving reliability while minimizing complexity increase.
3Productivity
If engine output control is continuously adjusted based on sensor readings, then the productivity of shifting operations is improved, but the harmful factors increase due to unnecessary engine output reduction when sensors fail
Solution Approach 1:
The control device performs preliminary abnormality detection by comparing sensor readings before executing engine output control. When a sensor breakdown is detected through inconsistent readings, the system takes preliminary action to stop or modify engine output control based on that sensor's data, preventing the harmful effect of unnecessary engine output reduction from occurring in the first place.
Data Source
AI summary
There is provided a shift control system for a saddle-type vehicle. A gear shift lever is configured to be operated by a driver. A gearshift sensor is configured to detect an operation on the gear shift lever. A shift cam is configured to rotate according to the operation on the gear shift lever. A gear position sensor is configured to detect a rotation angle of the shift cam. In the case where the gearshift sensor does not detect a detection result according to a detection result of the gear position sensor, or in the case where the gear position sensor does not detect a detection result according to a detection result of the gearshift sensor, a control device determines abnormality occurrence, and stops engine operation control based on the detection results of the gearshift sensor and the gear position sensor on the basis of the abnormality occurrence.