Parking Brake Control Method for Motor Vehicles

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Solution Overview

Problem

Modern motor vehicle braking systems with electrical components face complexity in determining and modulating the amplitude of braking actions between hydraulic and mechanical means to ensure effective parking brake functionality, especially in cases of electrical power failures.

Innovation Solution

A method for controlling a braking system that determines the power capability of electrical means to achieve disc locking, actuating electrical means alone if sufficient, and hydraulic means if not, simplifying the control process and ensuring effective clamping force application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electrical means are actuated alone to exert clamping force on the disc, then the control method is simpler, but this is only possible when the electrical means have sufficient power capability

Engineering Contradiction:
Improvecontrol method complexityVSAvoidparking brake functionality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control method performs a preliminary determination step before actuation to assess whether the electrical means have sufficient power capability. This preliminary assessment allows the system to select the appropriate actuation path (electrical only vs. hydraulic then electrical), thereby simplifying control when conditions permit while ensuring reliability when they don't.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the operating parameter from a fixed actuation sequence to a conditional selection based on power capability assessment. By evaluating the power parameter first, the system adapts its actuation strategy dynamically, achieving simplicity when electrical power is sufficient and reliability when it is not.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the hydraulic means are actuated before the electrical means, then effective clamping force is ensured, but the control process becomes more complex

Engineering Contradiction:
Improveparking brake functionalityVSAvoidcontrol method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The determination step serves as a preliminary action that assesses power capability before committing to a specific actuation sequence. This preliminary assessment prevents unnecessary complexity by only invoking the hydraulic-then-electrical sequence when truly needed, rather than making it the default for all operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of following the conventional approach of always using hydraulic means first (which would ensure reliability but increase complexity), the invention inverts the logic by attempting to use electrical means first when possible, and only resorting to hydraulic means when the determination step reveals insufficient power capability.

Inventive Principle:
Principle #13The other way round (Inversion)

3Speed

If the electrical means are used to achieve disc locking, then the response time is faster, but this requires sufficient power availability which may not be guaranteed

Engineering Contradiction:
Improvedisc locking speedVSAvoidpower availability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The determination step acts as a preliminary check of power availability before attempting fast electrical actuation. This ensures that the system only commits to the faster electrical path when power is actually available, preventing failures due to insufficient power while still achieving fast response when conditions permit.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts its actuation strategy based on real-time power capability assessment. Rather than using a fixed actuation method, the system transitions between electrical-only and hydraulic-then-electrical approaches based on the determination outcome, optimizing both speed and reliability according to available resources.

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 approach simplifies the control method, ensuring effective parking brake functionality by prioritizing hydraulic actuation before electrical, thereby eliminating the need for complex regulation and ensuring the vehicle remains stationary under various conditions.

Implementation Method 1

electrical means for driving the piston in order to produce a clamping force on the disk

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

hydraulic means for driving the piston in order to produce a clamping force on the disk

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 3

a brake comprising a piston for applying the brake pad on a disc

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3390181B1Method for controlling a braking system capable of carrying out the parking brake function
Publication Date: 2022.03.30 HITACHI ASTEMO FRANCE
  • EP3390181B1 patent drawingFigure 1~2
  • EP3390181B1 patent drawingFigure 3~4

AI summary

The invention relates to a method (10) for controlling a braking system for a motor vehicle, which is capable of implementing a parking brake function, the braking system comprising, in particular, a disk, a brake caliper and at least one piston movably mounted relative to the caliper and cooperating with the caliper in order to exert a disk clamping force on the disk, the braking system further comprising electric drive means for moving the piston relative to the caliper and hydraulic drive means for moving the piston relative to the caliper, the method (10) comprising at least one step (20, 26) consisting of exerting a disk clamping force that consists of moving the piston, by the electric drive means and/or the hydraulic drive means, characterised in that the method (10) comprises a step (26) of actuating the hydraulic means that consists of exerting a first clamping power on the piston, that is followed by a step (20) of actuating the electric means that consists of exerting an additional clamping power, until a total power is obtained that is high enough to lock the disk.