Accelerator Reaction Force Control via Variable Friction Plate

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Solution Overview

Problem

Existing accelerator pedal reaction force control systems increase the pedal force unnecessarily when transitioning to a low rotational speed/low load operating region, degrading driver feel and fuel efficiency due to automatic speed limiters limiting engine output.

Innovation Solution

An accelerator reaction force control apparatus that detects the pedal position and varies the reaction force beyond a base threshold, prohibiting further increases when an automatic speed limiter limits engine output, using a control unit to manage a variable friction plate and actuator to adjust the pedal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the accelerator pedal reaction force is increased based on accelerator pedal position to suppress further depression, then fuel consumption is reduced, but the accelerator pedal operating feel is degraded when the automatic speed limiter limits engine output

Engineering Contradiction:
Improvefuel consumptionVSAvoidaccelerator pedal operating feel
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The reaction force of the accelerator pedal is made dynamically adjustable based on operating conditions. The control unit varies the reaction force magnitude according to the detected accelerator pedal position and throttle valve opening degree, allowing the system to adapt between fuel efficiency mode (higher reaction force) and drivability mode (lower reaction force) depending on whether the automatic speed limiter is active

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by continuously monitoring the accelerator pedal position and throttle valve opening degree, then adjusting the reaction force accordingly. When the throttle opening degree is smaller than the accelerator pedal position (indicating speed limiter intervention), the control unit reduces the reaction force to maintain natural pedal feel

Inventive Principle:
Principle #23Feedback

2Productivity

If the reaction force limiting apparatus is employed to increase accelerator pedal reaction force, then the vehicle transitions to low rotational speed/low load operating region for better fuel efficiency, but the automatic speed limiter limits throttle opening degree causing unnecessary reaction force increase

Engineering Contradiction:
Improvefuel efficiencyVSAvoidaccelerator pedal operating feel
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The control unit continuously compares the accelerator pedal position with the throttle valve opening degree to detect when the automatic speed limiter is active. This feedback mechanism prevents unnecessary reaction force increases by identifying the conflict between driver input and system-imposed throttle limitations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The reaction force magnitude is dynamically adjusted based on the relationship between accelerator pedal position and throttle opening degree. When the throttle opening is restricted by the speed limiter, the system dynamically reduces reaction force to prevent degradation of operating feel while maintaining fuel efficiency benefits

Inventive Principle:
Principle #15Dynamics

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 solution reduces fuel consumption while maintaining good driver feel and vehicle operability by preventing unnecessary pedal force increases during low load conditions, ensuring efficient fuel use and comfortable driver interaction.

Implementation Method 1

The reaction force varying means includes a variable friction plate having a pair of friction members arranged facing opposite each other and configured to apply a frictional force

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2305987B1Accelerator reaction force control apparatus
Publication Date: 2013.10.23 NISSAN MOTOR CO LTD
  • EP2305987B1 patent drawingFigure 1
  • EP2305987B1 patent drawingFigure 2~3
  • EP2305987B1 patent drawingFigure 4

AI summary

An accelerator force control apparatus (100) is provided that basically comprising accelerator position detecting means (6), engine output control means (10), reaction force varying means (101) and reaction force increase prohibiting means (10). The accelerator position detecting means (6) is configured to detect an accelerator position. The engine output control means (10) is configured to control an engine output in accordance with the accelerator position. The reaction force varying means (101) is configured to vary a reaction force of an accelerator (2) by increasing the reaction force of the accelerator (2) beyond a base reaction force when the accelerator position is equal to or larger than a prescribed position threshold value. The reaction force increase prohibiting means (10) is configured to prohibit an increase of the reaction force of the accelerator (2) when a prescribed condition for limiting the engine output is satisfied regardless of the accelerator position.