Dynamic Clutch Torque Map Threshold Adjustment for Hill Start Assistance

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Solution Overview

Problem

Existing motor vehicle hill start assistance systems face inaccuracies in updating the torque transmission map of the clutch due to poor predetermination of position thresholds, which become unsuitable with clutch wear, leading to incorrect or lack of updating.

Innovation Solution

A device that recalculates and updates position thresholds for the clutch map based on the number of complete updates, using a comparator to determine when to modify these thresholds, and includes a hill start assistance system with a slope sensor and controlled braking to account for clutch wear, allowing automatic release of brakes when sufficient torque is supplied.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If predetermined position thresholds are used for updating the clutch torque map, then the updating process is simple, but the precision deteriorates with clutch wear

Engineering Contradiction:
Improveupdating process complexityVSAvoidclutch torque map precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent makes the position thresholds dynamic by automatically adjusting them based on the detected clutch torque characteristics. Instead of using fixed predetermined thresholds, the system calculates optimal thresholds based on actual clutch behavior, allowing the thresholds to adapt as the clutch wears over time, thereby maintaining measurement precision without increasing system complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback by using the detected clutch torque values to recalculate and update the position thresholds. The thresholds are continuously refined based on the difference between expected and actual torque readings, creating a closed-loop system that improves precision while keeping the updating process automated and simple

Inventive Principle:
Principle #23Feedback

2Device complexity

If position thresholds are not updated, then the device complexity remains low, but the reliability deteriorates due to clutch wear

Engineering Contradiction:
Improvethreshold management complexityVSAvoidhill start assistance reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system performs self-service by automatically updating its own position thresholds without requiring external intervention or complex manual calibration. The clutch torque map system self-adjusts by detecting wear patterns and recalculating thresholds autonomously, maintaining reliability while keeping the device complexity low through automated self-maintenance

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the parameters of the position thresholds based on detected clutch wear. By monitoring torque transmission characteristics over time and adjusting the threshold values accordingly, the system adapts to clutch degradation, ensuring continued reliability of the hill start assistance function without adding complex manual adjustment mechanisms

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If frequent threshold updates are performed, then the precision is maintained, but the loss of time increases due to repeated recalculations

Engineering Contradiction:
Improveclutch torque map precisionVSAvoidthreshold recalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system employs periodic action by updating the position thresholds at predetermined intervals rather than continuously. This approach maintains measurement precision by regularly refreshing the clutch torque map while minimizing time loss by avoiding unnecessary frequent recalculations, striking an optimal balance between precision and efficiency

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2183500B1Device and method for determining a mapping of the torque transmitted by a clutch in an automobile and hill-start assistance system for an automobile equipped with such device
Publication Date: 2014.07.16 RENAULT SA
  • EP2183500B1 patent drawingFigure 1
  • EP2183500B1 patent drawingFigure 2
  • EP2183500B1 patent drawing

AI summary

The invention relates to a device for determining, when driving a vehicle, a mapping (2) of the torque transmitted by the clutch of the automobile based on the position of a clutch control member (3). The device includes a means (5) for updating the mapping (2) based on position thresholds of the clutch control member (3). Said updating means (5) includes calculation means (7) for modifying the values of said thresholds based on the minimum and maximum values of the positions of the control member (3) stored in said mapping (2) and on the current values of said thresholds.