Clutch Slip Detection Using Twist Angle in Torsion-Damped Powertrains
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Solution Overview
Problem
Existing methods for detecting a slipping state of a clutch in motor vehicle powertrains, especially those equipped with a torsion damper, are prone to erroneous detections due to small amplitude speed differences caused by the damper, leading to inefficiencies in controlling the powertrain during transient phases like takeoff and gear changes.
Innovation Solution
A method that determines a twist angle between the output and input shafts and compares it to a torsion threshold, calculated based on the maximum transmissible torque and stiffness of the torsion damper, to accurately detect a slipping state, thereby improving detection reliability and avoiding torque gaps and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a speed difference threshold method is used to detect clutch slip state, then detection simplicity is maintained, but detection precision deteriorates due to small amplitude speed differences caused by torsion damper
Solution Approach 1:
The invention changes the detection parameter from speed difference to twist angle. The twist angle is calculated by integrating the speed difference between input and output shafts over time, transforming the detection approach from direct speed comparison to accumulated angular displacement measurement, thereby improving sensitivity to slight slip conditions
Solution Approach 2:
The invention replaces the mechanical speed threshold detection with a calculated twist angle threshold comparison. By using an integrator to accumulate speed differences and comparing the resulting twist angle against a predetermined threshold, the system achieves more precise detection without significant increases in device complexity
2Object-affected harmful factors
If a torsion damper is installed on the clutch disc to filter engine acyclism, then vibration reduction is achieved, but the ability to detect acyclism rate for slip detection is lost
Solution Approach 1:
The invention uses the twist angle as an intermediary parameter that bridges the torsion damper's vibration filtering function and the slip detection requirement. The twist angle accumulates speed differences over time, providing a integrated measure that reflects slip conditions while being insensitive to high-frequency vibrations filtered by the damper
Solution Approach 2:
The invention transitions from detecting slip in the speed domain to detecting it in the angular displacement domain. By integrating speed differences to obtain twist angle, the detection occurs in a different dimensional space where the torsion damper's vibration filtering does not mask the slip signal
3Measurement precision
If speed difference threshold calibration is set between 20-50 rpm to detect slip, then detection sensitivity is improved, but false detections increase due to torsion damper induced speed variations
Solution Approach 1:
The invention performs preliminary integration of speed differences to calculate the twist angle before comparing with the threshold. This preliminary action accumulates the slip signal over time, making the detection more sensitive to sustained slip conditions while less sensitive to transient speed variations caused by the torsion damper
Solution Approach 2:
The invention introduces a dynamic threshold comparison based on calculated twist angle rather than a fixed speed difference threshold. The twist angle naturally adapts to the system's operational characteristics, providing more reliable detection across different operating conditions while maintaining sensitivity to actual slip events
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the precision of slip state detection, optimizing powertrain control and reducing acoustic and vibration inconveniences, leading to improved driving experience by accurately identifying the transition from a closed to a slipping state.
Implementation Method 1
the torsion damper comprises springs allowing torsional freedom between the input shaft and the output shaft of the clutch
Implementation Method 2
determining a twist angle corresponding to relative rotation between the output shaft and the input shaft
Data Source
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AI summary
The invention relates to a method for detecting a slip state of a clutch for a motor vehicle powertrain, said clutch coupling an input shaft and an output shaft. According to the invention, the method comprises, during a closed state of said clutch, the following steps: determining (42) a torsion angle (αr) corresponding to a relative rotation between the output shaft and the input shaft, comparing (44) the torsion angle (αr) with a torsion threshold (αmax) of the clutch, and indicating (45) a slip state in the event of the detection of the torsion angle crossing the torsion threshold. The invention is applicable to conventional or hybrid propulsion motor vehicles, comprising a clutch that is preferably provided with a torsion damper. The invention allows the precision for controlling the powertrain and driving comfort to be improved.