Twin Clutch Gearshift Control for Transmission Load Reduction

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Solution Overview

Problem

The existing preshift control in automated manual transmissions increases inertia mass and load on the transmission output shaft, leading to worsened fuel efficiency due to the coupling with synchronous mesh mechanisms.

Innovation Solution

A gearshift control device that selectively engages or disengages the clutch using a twin clutch automated manual transmission system, optimizing the engagement of even-numbered or odd-numbered shafts to minimize transmission load and improve fuel efficiency by reducing unnecessary resistance during gear shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If preshift control is implemented by coupling the transmission input shaft and output shaft via synchronous mesh mechanisms, then the current gearshift position can be achieved, but the inertia mass and load on the transmission output shaft increase, worsening fuel efficiency

Engineering Contradiction:
Improvegearshift position achievementVSAvoidfuel efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The transmission system is divided into two independent clutch systems (first clutch and second clutch) operating on separate input shafts. This segmentation allows one clutch to remain disengaged during gear shifts, preventing the synchronous mesh mechanisms from coupling the input and output shafts, thereby eliminating the harmful inertia mass and load while still achieving the desired gearshift position through the engaged clutch system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful element (synchronous mesh mechanism coupling) is extracted or removed from the active transmission path during gear shifts. By using the twin clutch system, the patent ensures that the clutch not currently transmitting torque remains disengaged, effectively taking out the synchronous mesh mechanism from the load path, thus eliminating the energy loss associated with preshift operations

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If synchronous mesh mechanisms are used to achieve gearshift position, then gear transmission can be switched, but transmission load increases due to coupling inertia mass

Engineering Contradiction:
Improvegear transmission switchingVSAvoidtransmission load
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The transmission system is segmented into two independent clutch-gear sets (first clutch with first input shaft, second clutch with second input shaft). This segmentation enables one set to handle gear transmission switching while the other remains disengaged, preventing the coupling of inertia mass through synchronous mesh mechanisms and thereby reducing transmission load during gear shifts

Inventive Principle:
Principle #1Segmentation

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

The solution effectively reduces transmission load and enhances fuel efficiency during automatic driving by strategically managing clutch engagement and disengagement, thereby improving the overall performance of the vehicle.

Implementation Method 1

a clutch which transmits or blocks a torque of an engine which is a driving force source

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the synchronous mesh mechanisms are switched

Methodology Applied
Scientific EffectGear meshing: Gear

Implementation Method 3

the coupling with the synchronous mesh mechanism increases an inertia mass to be applied to the transmission output shaft and produces a load

Methodology Applied
Scientific EffectInertia: Inertia

Data Source

PatentEP3604863B1Transmission control device
Publication Date: 2022.01.12 ASTEMO LTD
  • EP3604863B1 patent drawingFigure 1
  • EP3604863B1 patent drawingFigure 2
  • EP3604863B1 patent drawingFigure 3

AI summary

There is proposed a gearshift control device which can reduce a transmission load due to preshift, and improve fuel efficiency of a vehicle. A gearshift control device which controls a transmission 50 including two systems of power transmission mechanisms, and preshifts the transmission 50 based on a traveling plan during automatic driving of a vehicle. The gearshift control device makes automatic driving preshift execution decision of planning control contents of the transmission 50 based on the traveling plan, and preshift execution decision of deciding whether or not to preshift the transmission based on a control plan of the transmission 50.