Clutch Slipping Point Estimation Without a Gearbox Speed Sensor
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Solution Overview
Problem
Existing methods for estimating the clutch slipping point position in a vehicle gearbox fail when the gearbox speed sensor is malfunctioning, preventing accurate clutch control and gear engagement.
Innovation Solution
A computer system estimates the clutch slipping point position by controlling the powertrain to a specific operating condition, applying a brake torque to prevent gearbox rotation, monitoring torque changes as the clutch moves between positions, and using known clutch torque transfer characteristics to determine the slipping point without relying on a gearbox speed sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the clutch slipping point position is estimated by monitoring the acceleration of the gearbox input shaft, then the clutch position can be determined accurately, but the method fails when the gearbox speed sensor is not functional
Solution Approach 1:
The patent introduces a braking component as an intermediary element to prevent rotation of the torque transferring shaft. This mediator enables the estimation of clutch slipping point position by creating a controlled condition where torque from the prime mover can be monitored without the complexity of speed sensor measurements, allowing accurate clutch position determination even when the gearbox speed sensor is non-functional
Solution Approach 2:
The patent replaces the sensor-based mechanical measurement system (gearbox speed sensor monitoring input shaft acceleration) with a torque-based measurement system. By monitoring the torque applied by the prime mover during controlled clutch engagement with the braking component preventing shaft rotation, the system determines clutch position without relying on the faulty speed sensor
2Ease of operation
If a gearbox speed sensor is used to monitor acceleration for determining clutch slipping point, then accurate clutch control is possible, but the system becomes dependent on this single sensor
Solution Approach 1:
The patent changes the measurement parameter from acceleration (requiring speed sensor) to torque (measurable by torque sensor). By monitoring torque applied by the prime mover during clutch engagement with the braking component holding the shaft stationary, the system achieves accurate clutch slipping point detection through a different physical parameter that does not depend on the speed sensor's functionality
Solution Approach 2:
The patent applies a braking component beforehand to prevent rotation of the torque transferring shaft during the estimation process. This preparatory action creates a controlled environment where torque measurements alone are sufficient to determine clutch position, cushioning against the potential failure of the speed sensor and ensuring the system can operate reliably
Data Source
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AI summary
A computer system comprising processing circuitry configured to estimate a clutch slipping point position (Xsp) of a clutch in a powertrain, by: - controlling the powertrain to a first operating condition in which a prime mover is running and in which rotation of a torque transferring shaft of a gearbox is prevented by a braking component different from the clutch, - controlling the clutch to move from a first clutch position towards a second clutch position, wherein the first clutch position is a disengaged or an engaged clutch position, - detecting that torque applied by the prime mover meets a predetermined first torque criterion, and in response thereto register an associated clutch position (Xb), in which the clutch is positioned when the first torque criterion is met, - estimating the clutch slipping point position based on a known clutch torque transfer characteristics and the registered clutch position.