DCT Acceleration Control via Clutch Torque Synchronization
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Solution Overview
Problem
In vehicles with dual clutch transmissions (DCT), acceleration delays and torque impacts occur when the engine speed is lower than the desired shift stage input shaft speed, leading to a suboptimal acceleration experience.
Innovation Solution
A control method that determines the engine speed relative to the desired shift stage input shaft speed, gradually increases the engagement-side clutch torque based on the difference between engine torque and clutch torque, and stabilizes engine speed synchronization to prevent acceleration delays and impacts, using a controller to manage clutch engagement and maintain engine torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine torque is forcibly reduced and then increased to synchronize engine speed with desired shift stage input shaft speed, then the engine speed synchronization is achieved, but the acceleration feeling is delayed
Solution Approach 1:
The controller performs preliminary action by determining whether engine speed is lower than desired shift stage input shaft speed before executing torque reduction, and by gradually increasing engagement-side clutch torque in advance to prepare for smooth synchronization without delay
Solution Approach 2:
The controller changes parameters by adjusting engagement-side clutch torque gradually based on the difference between engine torque and clutch torque, rather than forcibly reducing engine torque, thereby achieving speed synchronization while maintaining acceleration feeling
2Speed
If the engagement-side clutch torque is increased rapidly to accelerate the vehicle, then the acceleration response is improved, but torque impact and synchronization instability occur
Solution Approach 1:
The controller applies dynamics by gradually increasing engagement-side clutch torque based on the difference between engine torque and clutch torque, making the torque application dynamic and adaptive rather than fixed or abrupt, thereby achieving rapid acceleration response while maintaining stability
Solution Approach 2:
The controller uses feedback by continuously monitoring engine speed and comparing it with desired shift stage input shaft speed, then adjusting engagement-side clutch torque accordingly to maintain synchronization stability while achieving rapid acceleration response
3Productivity
If the engine torque is maintained during engagement-side clutch engagement, then the acceleration feeling is improved, but the engine speed synchronization becomes unstable
Solution Approach 1:
The controller changes parameters by adjusting engagement-side clutch torque gradually based on the difference between engine torque and clutch torque, allowing engine torque to be maintained while achieving stable synchronization through controlled clutch engagement parameters
Data Source
AI summary
An acceleration control method for a dual clutch transmission (DCT) vehicle, may include determining whether an engine speed is lower than a desired shift stage input shaft speed by a controller when a driver's demand for acceleration is verified, determining whether an engine speed increased by the demand for acceleration is equal to or greater than the desired shift stage input shaft speed by the controller, feedback-controlling an engagement-side clutch to reduce a slip caused by a difference between the engine speed and the desired shift stage input shaft speed while maintaining an engine torque by the controller when the engine speed is verified to be equal to or greater than the desired shift stage input shaft speed, and completing control by verifying whether synchronization of the engine speed with the desired shift stage input shaft speed is stabilized.