Clutch Microslip and Overpressure Control for Shift Comfort

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Solution Overview

Problem

Conventional drive train systems, particularly in dual clutch transmissions, face challenges in achieving efficient and comfortable operation due to slip losses and discomfort caused by torque imbalances during gear shifts, which are exacerbated by the inability to precisely set clutch torque without slip.

Innovation Solution

A method where an electronic computing device sets microslip during one operating phase and overpressure during another, allowing controlled microslip management to minimize slip losses and maintain driving comfort by adjusting clutch torque precisely, with test phases to determine optimal control parameters for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the clutch is operated with micro-slip during constant gear operation, then driving comfort is improved and torque irregularities are mitigated, but slip losses increase and energy efficiency deteriorates

Engineering Contradiction:
Improvedriving comfortVSAvoidslip losses
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The clutch control system dynamically switches between two operating modes: micro-slip mode during gear shifts to ensure comfort, and overpressure mode during constant gear operation to minimize energy loss. This dynamic adaptation allows the system to optimize performance based on real-time driving conditions, resolving the contradiction between comfort and efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the clutch operating parameters by adjusting the degree of slip between clutch plates. During gear shifts, a controlled micro-slip (small speed difference) is maintained for comfort, while during constant operation, the parameter changes to overpressure mode with minimal or no slip, thereby reducing energy losses while maintaining comfort when needed.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the clutch is operated with overpressure without slip, then energy efficiency is improved and slip losses are reduced, but driving comfort deteriorates due to torque imbalances during gear shifts

Engineering Contradiction:
Improveslip lossesVSAvoiddriving comfort
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The clutch control system employs periodic switching between overpressure mode and micro-slip mode based on the gear shift cycle. During constant gear operation, overpressure mode is maintained for efficiency, while during gear shift events, the system periodically transitions to micro-slip mode to ensure smooth torque transmission and comfort, then returns to overpressure mode afterward.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If conventional clutch control is used without targeted micro-slip setting, then device complexity is reduced, but driving comfort and shift quality deteriorate

Engineering Contradiction:
Improvecontrol system complexityVSAvoidshift quality
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The clutch control system incorporates feedback mechanisms that monitor clutch operating conditions, gear shift status, and vehicle dynamics. This feedback enables the electronic computing device to automatically adjust clutch torque and slip characteristics in real-time, achieving high shift quality and comfort without requiring complex mechanical adjustments or manual intervention.

Inventive Principle:
Principle #23Feedback

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

This approach reduces slip losses and enhances driving comfort by minimizing slip during constant gear operation and optimizing clutch torque settings, resulting in more efficient and comfortable gear shifts.

Implementation Method 1

a first clutch component (28) arranged on the input side (24) and a second clutch component (30) arranged on the output side (26), wherein the first clutch component (28) and the second clutch component (30) are pressed against one another with a clutch torque

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3615827B1Method for operating a clutch of a drive train for a motor vehicle and motor vehicle having a drive train
Publication Date: 2021.05.12 AUDI AG
  • EP3615827B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for operating a clutch (10) of a drive train (12) for a motor vehicle, wherein, by means of an electronic computing device (34) of the drive train (12), at least on micro-slip of the clutch (10) is specifically adjusted, whereby the clutch (10) is operated with the micro-slip during at least one operating phase (56, 58), wherein, by means of an electronic computing device (34), an over-pressing of the clutch (10) is specifically adjusted, whereby the clutch (10) is operated slip-free during at least one second operating phase (62, 64), which is different from the at least one operating phase (56, 58).