Vehicle Clutch Engagement Control Under Sensor Failure
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Solution Overview
Problem
The failure of sensors used to recognize the position of a dog clutch sleeve prevents the determination of clutch engagement or release, leading to potential failures in clutch control and risks such as engine stalling or undrivable conditions.
Innovation Solution
A vehicle clutch control method that adjusts the differential rotation threshold and uses differential rotation differences to determine clutch engagement or disengagement even when the engagement or disengagement sensor fails, ensuring reliable clutch operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an engagement sensor is used to detect clutch engagement, then the determination of clutch engagement is accurate, but the system becomes vulnerable to sensor failure
Solution Approach 1:
The patent introduces an intermediary detection method using differential rotation between the input shaft and output shaft of the clutch. When the engagement sensor fails, this intermediary measurement (differential rotation) serves as a backup to determine clutch engagement status, resolving the contradiction between measurement accuracy and system reliability.
Solution Approach 2:
The patent changes the detection parameter from direct position detection (engagement sensor) to rotational speed difference detection (differential rotation). By monitoring the parameter change in differential rotation, the system can infer clutch engagement status without relying solely on the engagement sensor, thereby improving reliability while maintaining detection accuracy.
2Measurement precision
If the differential rotation threshold is set to a small value for normal operation, then the engagement determination is precise, but the system cannot detect engagement when the sensor fails
Solution Approach 1:
The patent makes the differential rotation threshold dynamic rather than fixed. The threshold is adjusted based on the operational context and sensor status. When the engagement sensor is functional, a small threshold is used for precise determination. When the sensor fails, the threshold is adapted to accommodate the alternative detection method, ensuring the system remains versatile and adaptable to different operational conditions.
Solution Approach 2:
The patent changes the threshold parameter based on system state. By modifying the threshold value according to whether the engagement sensor is operational or failed, the system maintains both precision under normal conditions and adaptability under failure conditions. This parameter adjustment allows the same system to optimize for different operational scenarios.
3Device complexity
If the clutch engagement determination relies solely on the engagement sensor, then the control system is simple, but the system fails when the sensor malfunctions
Solution Approach 1:
The patent makes the control system universal by enabling it to function in multiple modes: normal mode using the engagement sensor and backup mode using differential rotation detection. This multi-functionality allows the same control system to handle both sensor-operational and sensor-failed conditions, improving reliability without significantly increasing complexity.
Solution Approach 2:
The patent implements preliminary detection of sensor status and prepares alternative detection methods in advance. By monitoring the engagement sensor and having the differential rotation detection method ready as a pre-prepared backup, the system can switch to the alternative method when sensor failure occurs, ensuring continuous reliable operation without requiring complex real-time decision-making.
Data Source
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AI summary
A clutch control method for a vehicle 1 is used in the vehicle 1 that has a second clutch mechanism 21 and a second clutch position sensor 52, which detects an engagement of the second clutch mechanism 21. The clutch control method for the vehicle 1 comprises executing an engagement of the second clutch mechanism 21 when the magnitude of the differential rotation of the second clutch mechanism 21 is less than or equal to a first prescribed value A1, and setting the target value of the differential rotation at the time of rotation synchronization to a second prescribed value A2, that is, offsetting the first prescribed value A1 to the larger side, at the time of failure of the second clutch position sensor 52, and then determining engagement of the second clutch mechanism 21 based on the differential rotation.