Friction Control Device for Vehicle Stability

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Solution Overview

Problem

Existing vehicle systems fail to effectively manage brake judder and torque steer, leading to vibrations and instability during braking and acceleration, due to inadequate control over friction forces in suspension and steering components.

Innovation Solution

Implementing a method to dynamically change the friction mode of components like suspension dampers, ball joints, and steering rack guides based on vehicle speed, deceleration rate, and operational conditions, using smart fluids or motors to adjust friction forces and torques, thereby attenuating brake judder and reducing torque steer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If friction control devices operate in a fixed friction mode, then the device complexity is reduced, but the vehicle stability deteriorates during braking and acceleration

Engineering Contradiction:

Improvevehicle stabilityVSAvoidfriction control device complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The friction control devices are designed to dynamically change their friction mode based on vehicle operating conditions. The controller receives inputs from sensors detecting vehicle speed, deceleration rate, and other parameters, then actuates the friction control devices to switch between first and second friction modes, enabling the system to adapt to varying driving conditions and maintain vehicle stability.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If friction forces are increased to reduce brake judder, then the brake judder is attenuated, but the handling and comfort deteriorate

Engineering Contradiction:

Improvebrake judderVSAvoidhandling and comfort

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system dynamically adjusts friction forces by switching between different friction modes based on real-time vehicle conditions. During braking events with high deceleration rates, the friction control devices switch to a second friction mode with higher friction forces to attenuate brake judder. During normal driving conditions, the system operates in a first friction mode with lower friction forces to maintain optimal handling and comfort characteristics.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The friction control devices change their friction parameter (friction force level) based on detected vehicle operating conditions. The controller monitors parameters such as vehicle speed, deceleration rate, and brake system operation, then actuates the friction control devices to adjust the friction force parameter, switching between a first friction mode for normal operation and a second friction mode for brake judder attenuation.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If friction modes are changed based on multiple parameters, then the adaptability is improved, but the measurement precision requirements increase

Engineering Contradiction:

Improveoperational adaptabilityVSAvoidparameter detection precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The friction control system changes operational parameters (friction mode) based on multiple detected vehicle parameters including vehicle speed, deceleration rate, throttle device velocity, transmission gear, and brake system operation. The controller integrates these multiple parameter inputs to determine when to switch between friction modes, enabling the system to adapt to diverse driving conditions while using standard sensor precision levels.

Inventive Principle:

Principle #35Parameter changes

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 enhances vehicle stability by reducing brake judder and torque steer, improving handling and comfort by dynamically adjusting friction forces and torques in response to operational conditions.

Implementation Method 1

using smart fluids or motors to adjust friction forces and torques

Methodology Applied

Scientific EffectElectrorheological Effect: Electrorheological Effect

Implementation Method 2

using smart fluids or motors to adjust friction forces and torques

Methodology Applied

Scientific EffectMagnetorheological Effect: Magnetorheological Fluid

Data Source

PatentUS8682532B2Vehicle including friction control device and methods

Publication Date: 2014.03.25 HONDA MOTOR CO LTD

AI summary

A method for controlling a vehicle comprises operating at least one friction control device in a first friction mode, said at least one friction control device comprising one of a suspension damper, a lower control arm ball joint, a strut bearing, a steering rack guide, and an outer tie rod ball joint. The method further comprises changing operation of said at least one friction control device from the first friction mode to a second friction mode.