Brake System Segmented Hydraulic Lines Vapor Lock

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Solution Overview

Problem

Conventional brake systems are vulnerable to Vapor Lock, especially during frequent braking on long downhill slopes, which affects the performance of both front and rear wheel brakes due to shared hydraulic lines and increased heat, leading to reduced braking efficiency and safety.

Innovation Solution

A brake system with separate hydraulic supply lines and switch valves that adjust fluid distribution based on travel conditions, switching to an H pipe mode when a vehicle is on a steep slope, ensuring that each wheel brake receives a dedicated fluid supply to prevent Vapor Lock and maintain braking performance without increasing system size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single shared hydraulic line is used for both front and rear wheel brakes, then the system complexity is reduced and cost is lowered, but the reliability deteriorates due to Vapor Lock affecting both brakes simultaneously

Engineering Contradiction:
Improvehydraulic line configurationVSAvoidbrake system reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The hydraulic system is segmented into two independent circuits: a first hydraulic line supplying the front wheel brake and a second hydraulic line supplying the rear wheel brake. This segmentation prevents Vapor Lock in one brake from affecting the other, resolving the reliability issue while maintaining reasonable system complexity through modular design.

Inventive Principle:
Principle #1Segmentation

2Force

If brake size is increased to provide greater braking force, then the braking force increases and safety is improved, but the weight increases and cost increases

Engineering Contradiction:
Improvebraking forceVSAvoidbrake system weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent employs hydraulic pressure transmission through separate hydraulic lines to deliver braking force to both front and rear wheels. This hydraulic system enables effective braking force distribution without requiring oversized mechanical brake components, thereby avoiding excessive weight and cost while maintaining safety.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If frequent braking is performed on long downhill slopes, then the braking frequency increases and control is improved, but the temperature increases causing Vapor Lock and reducing braking efficiency

Engineering Contradiction:
Improvebraking frequencyVSAvoidbrake oil temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

By segmenting the hydraulic system into separate lines for front and rear brakes, the heat generation from frequent braking is distributed and isolated. This prevents the cumulative heat effect that would otherwise cause Vapor Lock in a shared system, allowing sustained high-frequency braking on downhill slopes without loss of braking efficiency.

Inventive Principle:
Principle #1Segmentation

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 allows for safe operation and maximized braking force without increasing brake size or cost, by isolating the impact of Vapor Lock on the front wheel brake from the rear wheel brake, ensuring consistent performance even under high-frequency braking conditions.

Implementation Method 1

a master cylinder for generating pressurized fluid, a wheel brake in fluid communication with the master cylinder

Methodology Applied
Scientific EffectHydraulic pressure transmission: Pascal's Law

Implementation Method 2

the brake pad provided at the caliper is rubbed against the brake disc fixed to the vehicle wheel to generate heat of high temperature

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

It begins to boil when the brake oil reaches a predetermined threshold temperature. Vapor may be formed in the brake oil, which reduces a pedal effort of the brake to remarkably deteriorate a braking force

Methodology Applied
Scientific EffectBoiling: Boiling

Data Source

PatentEP3736186B1Brake system and control method thereof
Publication Date: 2022.12.28 HYUNDAI MOTOR CO LTD
  • EP3736186B1 patent drawingFigure 1
  • EP3736186B1 patent drawingFigure 2
  • EP3736186B1 patent drawingFigure 3

AI summary

A brake system may include a first hydraulic line; a second hydraulic line; a third hydraulic line; a fourth hydraulic line; a third switch valve; a fourth switch valve; a fifth hydraulic line; a sixth hydraulic line. The brake control unit can suppress a Vapor Lock even in a frequency brake operation in the section in which the downhill traveling from the highland to the flat is continued.