Clutch Actuator Control for Accurate Stroke Learning

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Solution Overview

Problem

Existing control systems for actuators that supply hydraulic pressure to slave cylinders to disengage and engage clutches face errors in learning the operation amount at the start of clutch engagement due to gaps between the piston and seal, especially under negative pressure conditions, leading to inaccurate clutch engagement.

Innovation Solution

A control apparatus and method that includes a first piston and a second piston, where the second piston forms part of the oil chamber and is slid to move the first piston, with repeated disengagement and engagement cycles to ensure positive pressure and contact between the pistons, allowing accurate learning of the operation amount at clutch engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the piston and seal are formed separately in the slave cylinder, then the manufacturing and assembly are simplified, but a gap is formed between the piston and seal under negative pressure, causing errors in learning the operation amount at clutch engagement

Engineering Contradiction:
Improveease of manufactureVSAvoidmeasurement precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The control apparatus performs preliminary actions by repeatedly disengaging and engaging the clutch before learning the operation amount. This preliminary operation ensures that the piston and seal are in proper contact, eliminating gaps caused by negative pressure, and establishes accurate initial conditions for subsequent measurement and learning operations.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the operation amount is learned immediately without preliminary operations, then the learning process is faster, but errors occur due to gaps between the piston and seal

Engineering Contradiction:
Improveloss of timeVSAvoidmeasurement precision
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The control apparatus performs preliminary actions by repeatedly disengaging and engaging the clutch before learning the operation amount. This preliminary operation ensures that the piston and seal are in proper contact, eliminating gaps caused by negative pressure, and establishes accurate initial conditions for subsequent measurement and learning operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control apparatus employs periodic action by repeatedly disengaging and engaging the clutch a predetermined number of times before learning the operation amount. This periodic operation cycles the hydraulic system to ensure positive pressure and proper contact between components, thereby eliminating measurement errors while maintaining efficient learning timing.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If the clutch is repeatedly disengaged and engaged before learning, then the operation amount is learned accurately, but the control process takes more time

Engineering Contradiction:
Improvemeasurement precisionVSAvoidloss of time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The control apparatus employs periodic action by repeatedly disengaging and engaging the clutch a predetermined number of times before learning the operation amount. This periodic operation cycles the hydraulic system to ensure positive pressure and proper contact between components, thereby eliminating measurement errors while maintaining efficient learning timing.

Inventive Principle:
Principle #19Periodic action

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 effectively reduces errors in learning the operation amount at clutch engagement by ensuring the pistons contact each other, enabling accurate detection and control of the clutch actuator's operation amount.

Implementation Method 1

an actuator that supplies a hydraulic pressure to a slave cylinder in which a first piston and a second piston are provided

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP2208906B1Control apparatus and control method for actuator
Publication Date: 2012.11.28 TOYOTA JIDOSHA KK
  • EP2208906B1 patent drawingFigure 1
  • EP2208906B1 patent drawingFigure 2
  • EP2208906B1 patent drawingFigure 3~4

AI summary

An ECU executes a program that includes a step (S102) of controlling a clutch actuator that supplies a hydraulic pressure to a slave cylinder so that the clutch is repeatedly disengaged and engaged; and a step (S104) of performing initial learning of a stroke of the clutch actuator, after controlling the clutch actuator so that the clutch is repeatedly disengaged and engaged.