Dual Clutch Transmission Torque Learning Control

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Solution Overview

Problem

Existing methods for learning transmission torque of a clutch in dual clutch-type transmissions face challenges in accuracy due to age-related deterioration and quality variations, and safety concerns when requiring drivers to apply brakes during learning processes.

Innovation Solution

A control device and method that includes a temperature sensor to detect hydraulic fluid temperature and a storage module for learning transmission torque changes, allowing learning to occur when a vehicle reaches a predetermined distance traveled, ensuring accurate torque learning without requiring brake application by generating torque circulations through controlled clutch engagement states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If transmission torque is estimated indirectly from clutch engagement starting point based on rotation number change, then learning can be executed without requiring driver to apply brakes, but transmission torque estimation accuracy deteriorates and clutch characteristic changes cannot be dealt with

Engineering Contradiction:
Improvelearning execution convenienceVSAvoidtransmission torque estimation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the indirect estimation method based on rotation number changes with a direct measurement method using engine torque. By substituting the mechanical observation approach with direct torque measurement, the system achieves both ease of operation and high measurement precision simultaneously.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces engine torque as an intermediary parameter to accurately determine clutch transmission torque. Instead of directly observing clutch behavior, the system uses engine torque as a mediator to calculate the transmission torque, providing more accurate results while maintaining operational convenience.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If transmission torque is learned based on engine torque with clutch partially engaged in predetermined gear, then transmission torque learning accuracy improves, but driver must apply brakes to prevent vehicle start, compromising safety

Engineering Contradiction:
Improvetransmission torque learning accuracyVSAvoidvehicle safety
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the clutch engagement process into distinct phases: a first phase for learning transmission torque in neutral state without brake application, and a second phase for learning in predetermined gear with brake application. This segmentation allows the system to prioritize safety by performing the majority of learning in the safer first phase, while still maintaining high accuracy through the complementary second phase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs transmission torque learning partially in two different states rather than requiring complete learning in a single state. By executing learning in both neutral state and predetermined gear state, the system achieves comprehensive torque characteristics without always requiring the unsafe brake application condition.

Inventive Principle:
Principle #16Partial or excessive action

3Device complexity

If transmission torque is estimated based on single clutch engagement starting point, then learning process is simplified, but learning accuracy cannot be ensured due to inability to account for clutch deterioration and quality variations

Engineering Contradiction:
Improvelearning process complexityVSAvoidlearning accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements periodic learning actions at different stages: initial learning in neutral state, and subsequent learning in predetermined gear state. This periodic execution of learning in multiple phases ensures comprehensive torque characterization while accounting for clutch deterioration and quality variations, without excessively increasing process complexity.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent performs preliminary learning of transmission torque in neutral state before actual driving conditions. This preliminary action establishes a baseline torque value that accounts for initial clutch characteristics, which is then refined through subsequent learning phases, ensuring high accuracy without overly complicating the overall learning process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3205907B1Control device and control method for dual clutch-type transmission
Publication Date: 2019.11.20 ISUZU MOTORS LTD
  • EP3205907B1 patent drawingFigure 1
  • EP3205907B1 patent drawingFigure 2
  • EP3205907B1 patent drawingFigure 3A~3B

AI summary

A dual clutch-type transmission control device is provided which improves the accuracy with which transmission torque is learned. A dual-clutch transmission includes a clutch apparatus 20 having a first clutch 21 and a second clutch 22, a first input shaft 31, a second input shaft 32, a counter shaft 34, an output shaft 33, an auxiliary transmission portion 40 including a first input gear pair 41 and a second input gear pair 42, a main transmission portion 50 including an output gear pair 51, and learning modules 61, 62, and the learning modules 61, 62 shift the main transmission portion 50 into a neutral state, disengage both the first and second clutched 21, 22, generate a torque change in an engine 10 by keeping the engine 10 running at a predetermined revolution number, engaging partially one of the first and second clutches 21, 22, and thereafter engaging the other clutch gradually partially and learn an amount of change of torque associated with the torque change as transmission torque of the other clutch.