DCT Clutch Touch Point Search via Acceleration Difference

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Solution Overview

Problem

Conventional methods for searching the touch point of a DCT clutch are ineffective when a gear is engaged with the clutch, leading to unstable control quality and inability to guarantee reliable clutch operation due to temperature changes and abrasion, especially when the clutch is in a slip control state.

Innovation Solution

A method that involves checking the touch point searching conditions by detecting the absolute difference in acceleration values between the engine and the driving clutch when the non-driving clutch is in gear and applying its position value to the engine, determining the touch point based on this difference and compensating with an offset value for torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional touch point search method based on velocity change value is used, then touch point can be searched when clutch is applied, but touch point cannot be searched when gear is engaged with clutch in advance

Engineering Contradiction:

Improvetouch point search capabilityVSAvoidcontrol quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the search condition from static (clutch applied state) to dynamic (slip control state during gear engagement). By detecting acceleration differences between engine and driving clutch during the dynamic slip control process, the system can now search for touch points in previously inaccessible states, improving adaptability while maintaining reliability through the offset compensation mechanism

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces offset compensation values that correspond to engine torque to adjust the detected touch point position. This parameter adjustment allows accurate touch point identification even when searching during slip control with gear engagement, resolving the contradiction between expanded search capability and control reliability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If touch point search is performed during slip control state with gear engagement, then control quality is improved, but conventional search methods become ineffective

Engineering Contradiction:

Improvecontrol qualityVSAvoidtouch point detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces the conventional velocity-based detection method with an acceleration-based detection method. By measuring acceleration values and their differences during slip control, the system overcomes the limitations of velocity-based methods in gear-engaged states, making touch point detection feasible in the slip control state while maintaining control quality

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses acceleration difference as an intermediary indicator to indirectly detect touch point position. Instead of directly measuring clutch plate contact, the system detects the acceleration difference between engine and driving clutch, which serves as a reliable proxy signal for touch point identification during slip control with gear engagement

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If clutch position is applied without offset compensation, then search process is simple, but touch point determination is inaccurate

Engineering Contradiction:

Improvesearch process complexityVSAvoidtouch point position accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent performs preliminary calculation of offset compensation values corresponding to engine torque before final touch point determination. This advance preparation of compensation data allows the system to maintain relatively simple search procedures while achieving accurate touch point positioning through the pre-computed offset adjustments

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9989110B2Method for searching touch point of DCT clutch

Publication Date: 2018.06.05 HYUNDAI KEFICO CORP

AI summary

The present invention provides a method for searching a touch point of a clutch in a dual clutch transmission, including: (a) a step of checking whether a touch point searching condition for a non-driving clutch and a driving clutch is met or not; (b) when the search condition of the step (a) is met, a step of detecting a searching point at which an absolute value of a difference between an acceleration value of an engine and an acceleration value of the driving clutch is larger than a threshold value after applying a position value of the non-driving clutch to the engine; and (c) a step of determining a position of the non-driving clutch corresponding to the searching point as the touch point.