Friction Element Temperature Warning Device

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Solution Overview

Problem

Existing temperature warning systems for friction elements, such as clutches, issue excessive warnings when the element has not experienced burning, leading to insecure feelings for drivers due to the same upper limit temperature being used for both burned and unburned elements, resulting in inappropriate attention calling.

Innovation Solution

A temperature warning device and method that adjust the timing of warning issuance based on the heat resistance of the friction element, allowing a longer delay before warning when the temperature exceeds the upper limit for the first time, and immediate warning when exceeded subsequently, to better correspond with the element's heat resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the same upper limit temperature is used for both burned and unburned friction elements, then the warning system can be simplified, but excessive warnings are issued when the friction element has not experienced burning, causing insecure feelings to the driver

Engineering Contradiction:
Improvewarning system complexityVSAvoidwarning accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The warning system dynamically adjusts the upper limit temperature threshold based on the burning history of the friction element. For unburned elements, a higher threshold is applied, while for burned elements, a lower threshold is used. This dynamic adaptation resolves the contradiction by maintaining warning accuracy across different element states without requiring completely separate warning systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the temperature parameter (upper limit threshold) based on the condition of the friction element. When the element is unburned, a higher temperature threshold is used; when burned, a lower threshold is applied. This parameter change allows the same warning system to appropriately handle different element conditions, preventing excessive warnings while maintaining simplicity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the upper limit temperature is set lower to prevent burning, then safety is improved, but unnecessary warnings are issued during normal operation, causing driver anxiety

Engineering Contradiction:
ImprovesafetyVSAvoiddriver comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The warning threshold dynamically adapts based on the friction element's burning history. For unburned elements operating normally, a higher threshold prevents unnecessary warnings and driver anxiety. For burned elements requiring closer monitoring, a lower threshold ensures safety. This dynamic adjustment resolves the contradiction between safety and driver comfort.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different temperature thresholds are applied based on the local condition of the friction element (burned or unburned state). This localized quality adjustment ensures that the warning system provides appropriate sensitivity for each element state, preventing both unnecessary warnings and safety compromises.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the upper limit temperature is set higher to avoid unnecessary warnings, then driver comfort is improved, but the risk of burning increases

Engineering Contradiction:
Improvedriver comfortVSAvoidburning prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system dynamically adjusts the temperature threshold based on the element's condition. For unburned elements, a higher threshold maintains driver comfort by avoiding unnecessary warnings. For burned elements, the threshold automatically lowers to prevent burning. This dynamic adjustment resolves the contradiction between comfort and safety.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The temperature parameter is changed based on the burning history of the friction element. Unburned elements operate with a higher temperature parameter for comfort, while burned elements switch to a lower parameter for safety. This parameter change strategy resolves the contradiction without requiring separate warning systems.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2985483B1Friction element temperature warning device and temperature warning method
Publication Date: 2020.08.26 NISSAN MOTOR CO LTD
  • EP2985483B1 patent drawingFigure 1
  • EP2985483B1 patent drawingFigure 2
  • EP2985483B1 patent drawingFigure 3

AI summary

A period of time, from when the temperature of the friction element exceeds the upper limit temperature until when the warning is issued, is made longer when the temperature of the friction element exceeds the upper limit temperature for a first time, than when the temperature of the friction element exceeds the upper limit temperature for a second or subsequent time.