Clutch Torque Control for Automated Manual Transmission Impact Reduction
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Solution Overview
Problem
Automated manual transmission systems experience clutch engagement impacts due to variations in torque characteristics over time, leading to errors in predicting the clutch touch point, resulting in potential jolts or slips during clutch engagement.
Innovation Solution
A method for controlling the clutch torque that varies its rising slope based on whether the brake is in operation, with distinct control strategies before and after the clutch touch point, including standby control and torque control steps to minimize engagement impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the clutch torque rising slope is made steep to improve responsiveness, then the clutch engagement speed increases, but clutch engagement impact and jolts occur due to torque prediction errors
Solution Approach 1:
The clutch control system dynamically adjusts the torque rising slope based on real-time brake operation status. When the brake is applied, a steeper torque rising slope is used for faster engagement. When the brake is not applied, a gentler slope is used to prevent impacts. This dynamic adaptation resolves the contradiction between engagement speed and impact reduction.
Solution Approach 2:
The system changes the torque control parameter (rising slope) based on brake operation conditions. By switching between different torque rising profiles (steep vs. gentle slopes), the system optimizes both responsiveness and comfort depending on the driving situation, eliminating the need for a fixed torque curve.
2Device complexity
If a fixed torque-stroke curve is used for clutch control, then the control algorithm is simple, but errors occur in predicting the clutch touch point due to variations in torque characteristics over time
Solution Approach 1:
The system applies standby torque before the predicted touch point to prepare for engagement. This preliminary action compensates for prediction errors by ensuring the clutch is ready to engage smoothly regardless of variations in the actual touch point position, maintaining accuracy without complex real-time adjustments.
Solution Approach 2:
Instead of using a fixed torque-stroke curve, the system dynamically adjusts the torque profile based on brake operation status. This dynamic approach adapts to varying torque characteristics over time while keeping the control logic relatively simple, resolving the contradiction between algorithm complexity and prediction accuracy.
3Productivity
If the clutch torque rises rapidly to meet target torque, then the power transmission efficiency is improved, but jolts and slips occur during engagement
Solution Approach 1:
The system dynamically selects the torque rising profile based on brake operation. When the brake is applied, rapid torque rise is permitted for efficient power transmission. When the brake is not applied, a controlled gentler rise prevents jolts and slips. This dynamic adjustment resolves the contradiction between efficiency and smooth engagement.
Solution Approach 2:
Different torque control strategies are applied to different operational contexts (brake applied vs. brake not applied). By tailoring the torque rising characteristics to the specific operating condition, the system achieves both rapid power transmission when needed and smooth engagement when comfort is prioritized.
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 effectively reduces clutch engagement impacts and improves driving responsiveness by adapting clutch torque control to the brake's operation status, ensuring smoother transitions and enhanced control.
Implementation Method 1
the frictional coefficient, and thus, an error may occur in the learning touch point
Data Source
AI summary
The present disclosure relates to a technique of suppressing the occurrence of an impact caused by clutch engagement by differently controlling a clutch depending on whether or not a brake is in operation. Disclosed is a method of controlling a clutch for a vehicle, which effectively reduces engagement impact that occurs when the clutch is engaged by performing control such that a rising slope of clutch torque up to a touch point is gentler when the brake is not in operation than when the brake is in operation.