Brake Control System with Master Pressure Controller

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Solution Overview

Problem

Existing brake control systems fail to maintain required braking force when the brake booster is out of order, leading to a loss of braking force and discomfort for the driver due to inadequate sensing and control of brake operating conditions.

Innovation Solution

A brake control system that includes a master pressure controller and wheel pressure controller, which execute bidirectional communication and share control instructions to generate braking force as required by the driver, using sensors to detect displacement and force of the brake pedal and a driving motor to amplify the braking force, eliminating the need for a separate device to generate brake pedal reaction force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump of the anti-lock control system is used to suppress the drop of braking force when the brake booster is out of order, then the braking force can be partially maintained, but the response is delayed because the master pressure recovery takes time and the driver feels loosening of braking force

Engineering Contradiction:
Improvebraking force maintenanceVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system detects brake booster failure in advance and preemptively activates the backup braking mechanism through the wheel pressure control mechanism, rather than waiting for braking force drop to occur. This preliminary action ensures immediate response and maintains braking force without delay.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The wheel pressure control mechanism acts as an intermediary between the brake pedal operation and the final braking force application. When the brake booster fails, this intermediary mechanism directly generates the required braking force through the brake hydraulic mechanism, bypassing the failed booster and eliminating response delay.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If a vacuum booster is used as a brake booster, then braking force amplification is achieved, but the possibility of trouble increases compared to conventional systems

Engineering Contradiction:
Improvebraking force amplificationVSAvoidsystem reliability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The system incorporates a backup wheel pressure control mechanism that is prepared in advance to compensate for potential brake booster failures. This redundant mechanism ensures that if the vacuum booster fails, braking force can still be generated through the hydraulic mechanism, cushioning against the reliability risk.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system changes the operating parameters and control mode when brake booster failure is detected. Instead of relying on vacuum-assisted mechanical braking, the system switches to electrically-controlled hydraulic braking with adjusted pressure parameters, maintaining braking performance while bypassing the failed component.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the master pressure is controlled to a target value using a master pressure sensor, then braking force can be maintained, but the system complexity increases and response is delayed due to great depressing force and stroke requirements

Engineering Contradiction:
Improvebraking force stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes the master pressure sensor and complex master pressure control logic from the system. Instead of using sophisticated pressure sensing and control, the system directly uses wheel pressure sensors and a simplified control algorithm that calculates required braking force based on sensor inputs, reducing complexity while maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system implements a feedback control mechanism where wheel pressure sensors continuously monitor the actual braking force applied to each wheel, and the wheel pressure control mechanism adjusts hydraulic pressure in real-time based on this feedback to maintain the target braking force, achieving stability without complex master pressure control.

Inventive Principle:
Principle #23Feedback

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

The system ensures consistent braking force and stability even when the brake booster fails, reducing system size and weight, and providing fail-safe operation by detecting and responding to driver input through multiple sensors.

Implementation Method 1

sensors to detect displacement and force of the brake pedal

Methodology Applied
Scientific EffectForce detection:

Implementation Method 2

a driving motor to amplify the braking force

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

master pressure controller and wheel pressure controller... to generate braking force

Methodology Applied
Scientific EffectHydraulic pressure generation: Hydraulic Press

Data Source

PatentEP2105364B1Brake control system
Publication Date: 2015.08.12 HITACHI LTD
  • EP2105364B1 patent drawingFigure 1
  • EP2105364B1 patent drawingFigure 2
  • EP2105364B1 patent drawingFigure 3A~3B

AI summary

A brake control system for a vehicle includes a first controller (3) having a first brake operation quantity sensor (8) and a second controller (5) executing a different control from that of the first controller and having a second operation quantity sensor. The second controller may include a master pressure acquisition unit (56) for acquiring a master pressure and a failure detection unit for detecting a failure of the first controller on the basis of the brake operation quantity detected by the second brake operation quantity sensor and the master pressure acquired by the master pressure acquisition unit.