Wet Clutch Torque Estimation Under Varying Operating Conditions
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Solution Overview
Problem
Existing methods for determining torque transmitted by wet clutches are imprecise due to variations in operating conditions, leading to degraded vehicle comfort and excessive slippage.
Innovation Solution
A method and device that calculate torque transmitted by a clutch using a characteristic function that accounts for operating states such as oil temperature, flow rate, and actuation pressure, incorporating gain and offset corrections based on real-time measurements and derivatives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a predetermined characteristic curve is used to determine clutch torque, then the method is simple, but the torque estimation is imprecise due to variations in operating conditions
Solution Approach 1:
The patent applies dynamics by transforming the static predetermined characteristic curve into a dynamic characteristic function that adapts in real-time to changing operating conditions. The gain and offset parameters are continuously updated based on measured operating states (oil temperature, flow rate, actuation pressure), allowing the torque estimation to dynamically adjust to varying clutch conditions while maintaining calculation efficiency through an affine mathematical model.
2Reliability
If the characteristic curve is corrected based on clutch friction coefficient, then some operating variations are accounted for, but the torque estimation remains unreliable due to insufficient parameter coverage
Solution Approach 1:
The patent implements parameter changes by introducing multiple operating state parameters (oil temperature, oil flow rate, actuation pressure) that directly influence the characteristic function. These parameters are measured in real-time and used to dynamically adjust the gain and offset of the affine function, comprehensively accounting for various operating conditions including thermal effects, lubrication variations, and hydraulic actuation changes, thereby significantly improving torque estimation reliability.
Data Source
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AI summary
The invention relates to a method (300) for determining a torque transmitted by a vehicle clutch, the method comprising: receiving (302) a control variable from an actuator of the clutch, the actuator being configured to move the clutch; measuring (304, 326) one or more operating states of the clutch; calculating a gain depending on the operating state or states; calculating an offset depending on the operating state or states; and calculating the torque transmitted depending on the control variable by using a characteristic function of the clutch, the characteristic function of the clutch being an affine function of the torque transmitted depending on the control variable, where the gain is the slope and the offset the y-intercept.