Straddled Vehicle Gear Position Sensor Failure Detection
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Solution Overview
Problem
Existing straddled vehicle gear position sensor failure detection methods, such as those described in JP H10 281279 A, are inadequate in detecting sensor failures caused by prolonged vibration and contamination, leading to inaccurate gear position readings.
Innovation Solution
A gear position sensor failure detector is implemented using engine rotation speed and vehicle speed sensors, which are less susceptible to vibration and contamination, to estimate the actual gear position and compare it with the detected position, thereby enhancing failure detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact-type gear position sensor is used to detect gear position, then the sensor can provide direct contact-based detection, but the sensor becomes susceptible to wear from prolonged vibration and contamination, leading to detection failures
Solution Approach 1:
The patent replaces the contact-type mechanical sensor with a contactless sensor that uses electromagnetic fields to detect gear position. This substitution eliminates mechanical contact, thereby preventing wear from vibration and contamination while maintaining detection accuracy. The contactless sensor detects changes in electromagnetic characteristics caused by gear position changes without physical contact.
2Reliability
If voltage range checking is used to detect sensor failure, then short-circuit and disconnection can be identified, but failures caused by contact wear and contamination remain undetected
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the output signal of the gear position sensor and compares it with expected gear position values based on vehicle operation state. When a discrepancy is detected, the system determines sensor failure and activates warning indicators, providing continuous feedback to detect various failure modes including contact wear and contamination.
Solution Approach 2:
The patent introduces an intermediary control unit that acts as a mediator between the gear position sensor and the vehicle's control systems. This control unit processes sensor signals, validates them against expected operational parameters, and determines failure conditions, thereby enhancing detection capability for subtle failures like contact wear without requiring direct sensor modification.
3Measurement precision
If the gear position sensor is exposed to detect gear position accurately, then detection capability is maintained, but the sensor becomes vulnerable to contamination from water and dust
Solution Approach 1:
The patent replaces the vulnerable contact-type sensor with a contactless sensor that uses electromagnetic fields for detection. This eliminates the need for physical exposure and contact, thereby preventing contamination from water and dust while maintaining accurate gear position detection through electromagnetic characteristic changes.
Solution Approach 2:
The patent employs a protective structure that encapsulates the sensor elements, creating a barrier against contamination from water and dust. This protective enclosure allows the sensor to maintain detection capability while being isolated from harmful environmental factors.
Data Source
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AI summary
A straddled vehicle having a gear position sensor failure detector which is able to improve the capability of detecting a failure of a gear position sensor is provided. An ECU (90) which is a gear position sensor failure detector includes a gear position estimation unit (93) and a sensor failure detection unit (94). The gear position estimation unit (93) estimates the gear position of a gearbox based on a transmission ratio which is estimated based on a signal from an engine rotation speed sensor (71) and a signal from a vehicle speed sensor (16). The engine rotation speed sensor (71) and the vehicle speed sensor (16) are contactless sensors. A gear position sensor failure determination unit (95) of the sensor failure detection unit (94) determines whether there is a failure in a gear position sensor (77) by comparing the gear position estimated by the gear position estimation unit (93) with the gear position detected by the gear position sensor (77). The gear position sensor (77) is provided in a crankcase which houses a crankshaft and the gearbox.