Dual Clutch Transmission Load Distribution Control

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Solution Overview

Problem

Dual clutch transmissions experience uneven wear on clutches due to high load during start, leading to reduced durability and impaired driving comfort, as existing methods either increase wear on the support clutch or require additional components.

Innovation Solution

A method of controlling dual clutch transmissions that brings both clutches into a half-clutch state at start, distributing load and calculating absorbed energy to determine when to engage the support clutch, thereby reducing wear on the start gear clutch and minimizing wear on the support clutch without additional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the clutch on the start gear side is used for starting, then the gear shift operation can be performed, but the clutch experiences high load and wear during start

Engineering Contradiction:
Improvegear shift operationVSAvoidclutch durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent divides the clutch usage into two separate clutches (first clutch C1 and second clutch C2), where one clutch handles start operations while the other handles gear shifts. This segmentation allows the start clutch to be protected from excessive wear by switching to the other clutch after start, thereby improving overall reliability while maintaining operational capability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If both clutches are used during start to reduce wear on the start clutch, then clutch durability improves, but the support clutch experiences increased wear

Engineering Contradiction:
Improveclutch durabilityVSAvoidsupport clutch wear
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The control device monitors the rotational speed difference between input and output shafts of the second clutch, and based on this feedback, determines whether to connect the first clutch during start. When the rotational speed difference exceeds a threshold, the first clutch is connected to share the load; otherwise, only the second clutch is used. This feedback-based control minimizes unnecessary wear on the support clutch while protecting the start clutch.

Inventive Principle:
Principle #23Feedback

3Reliability

If the first clutch is connected during start to reduce wear on the second clutch, then both clutches experience reduced wear, but the device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improveclutch wear reductionVSAvoidcontrol mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control device automatically determines whether to connect the first clutch based on real-time rotational speed data from sensors. The system self-regulates the clutch connection state without requiring complex external control mechanisms or additional components. This self-service approach reduces wear on both clutches while maintaining relatively simple device architecture.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2730814B1Dual clutch transmission control method, dual clutch transmission, and vehicle mounted therewith
Publication Date: 2021.02.24 ISUZU MOTORS LTD
  • EP2730814B1 patent drawingFigure 1
  • EP2730814B1 patent drawingFigure 2(a)~2(d)
  • EP2730814B1 patent drawingFigure 3

AI summary

Provided is a method of a dual clutch transmission, a dual clutch transmission, and a vehicle equipped with the same which can reduce the load on a clutch on a start gear side to reduce the wear thereof and therefore make the clutch replacement interval longer. There are a first input shaft 11 configured to be connected to a first clutch C1 and a second input shaft 12 configured to be connected to a second clutch C2. A set of odd-numbered gears G1, G3, and G5 and a set of even-numbered gears G2, G4, and G6 are arranged respectively across the first input shaft and second input shaft 11 and 12 and an output shaft 3. When a vehicle starts, an absorbed energy Eabs by the second clutch C2 is calculated while a start gear DG2 is partially connected to the second input shaft 12. The first clutch C1 is partially connected (half clutch state) to the first input shaft 11, to which a support gear SG3 is synchronously engaged, when the absorbed energy Eabs exceeds a set value Elim which is a predetermined threshold, the support gear SG3 having a gear ratio greater than that of the start gear DG2 by one speed or higher.