Clutch Torque Estimation Using Engine Angular Speed Feedback
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Solution Overview
Problem
Conventional methods for estimating clutch torque in dual clutch transmissions (DCTs) using dry clutches are inaccurate due to errors in engine torque models, especially during transient engine states, leading to discrepancies between estimated and actual torque values.
Innovation Solution
A method that adjusts for errors by deducing engine transient torque based on measured angular speed, static torque, and load torque, and compensates for differences using integration and error compensation values, with feedback to refine the estimated clutch torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional observer theory methods are used to estimate clutch torque based on ECU engine torque data, then the estimation process is simple, but the accuracy is poor due to errors in engine torque models during transient states
Solution Approach 1:
The patent implements feedback control by continuously comparing the measured engine angular speed with the estimated engine angular speed, using the speed difference to correct the clutch torque estimation. The measured engine angular speed from sensors is fed back into the estimation algorithm to adjust the estimated engine angular speed and consequently refine the clutch torque calculation, thereby improving accuracy without excessive complexity
Solution Approach 2:
The patent introduces engine angular speed difference as an intermediary variable to bridge the gap between measured and estimated engine parameters. By using the difference between measured and estimated engine angular speeds as a correction term, the system indirectly compensates for errors in engine torque models during transient states, improving clutch torque estimation accuracy
2Ease of operation
If engine torque data from ECU is used directly for clutch torque estimation, then the process is straightforward, but errors occur during transient states such as creep and departure
Solution Approach 1:
The patent replaces direct reliance on ECU engine torque data with a physics-based estimation approach using engine angular speed measurements and moment of inertia. Instead of using uncertain torque models from the ECU, the system measures engine angular speed with sensors and calculates torque through mechanical principles (integration of angular acceleration multiplied by moment of inertia), providing more reliable results during transient states
Solution Approach 2:
The patent changes the fundamental parameter used for estimation from ECU-reported engine torque to measured engine angular speed. By measuring angular speed directly with sensors and deriving torque from the rate of change of angular speed combined with moment of inertia, the system transforms the estimation approach to one that remains reliable during transient operating conditions
Data Source
AI summary
A method of estimating a torque of a transmission clutch may include adjusting an error, deducing an estimated engine angular speed and deducing an estimated clutch torque. The error may be adjusted by deducing an engine transient torque based on an engine angular speed measured using a sensor, an engine static torque deduced using a data map and a load torque depending on a driving load. The estimated engine angular speed may be deduced based on the engine static torque and the engine transient torque. The estimated clutch torque may be deduced by summing an integration value and an error compensation value. The integration value and the error compensation value may be deduced based on a difference between the estimated engine angular speed and the measured engine angular speed.