Brake-by-wire Pedal Travel Simulator Force Control

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Solution Overview

Problem

Existing brake-by-wire systems are costly, complex, and require monitoring due to the need for separate devices to switch the pedal travel simulator on and off, which is inefficient and increases operational complexity.

Innovation Solution

A controllable force-displacement characteristic of the pedal travel simulator allows for an additional path with a limited force level to be released, eliminating the need for separate shutdown mechanisms and enabling the simulator to remain active in fallback modes, thus simplifying the system and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate device is provided to switch the pedal travel simulator on and off, then operational safety is improved, but device complexity and cost increase

Engineering Contradiction:
Improveoperational safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the switching function with the existing brake pedal mechanism by using a articulated connection between piston and piston rod. This allows the pedal travel simulator to be automatically activated/deactivated through the driver's natural braking action, eliminating the need for separate switching devices while maintaining operational safety

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The brake pedal mechanism is given multiple functions: it serves both as the primary braking actuator and as the switching mechanism for the pedal travel simulator. The articulated connection enables the same mechanical structure to control simulator activation based on braking intensity, reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If the pedal travel simulator is deactivated outside brake-by-wire mode, then system complexity is reduced, but braking performance may be compromised

Engineering Contradiction:
Improvedevice complexityVSAvoidbraking performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic activation of the pedal travel simulator based on real-time operating conditions. The articulated connection allows the simulator to be automatically engaged when braking forces exceed a threshold, ensuring optimal braking performance is maintained regardless of whether the vehicle is in brake-by-wire or fallback mode

Inventive Principle:
Principle #15Dynamics

3Reliability

If monitoring of the electro-hydraulic device is required, then operational safety is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveoperational safetyVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs self-monitoring through the articulated connection mechanism between piston and piston rod. The mechanical design inherently detects activation conditions and automatically adjusts simulator engagement without requiring external monitoring systems, maintaining operational safety while simplifying operation

Inventive Principle:
Principle #25Self-service

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 system complexity, eliminates the need for monitoring, and ensures consistent braking performance by integrating the pedal travel simulator within the existing components, enhancing operational safety and cost-effectiveness.

Implementation Method 1

a spring element to extend the pedal travel, which is compressible from a predetermined foot force applied to the brake pedal

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2387521B1"brake-by-wire" type braking system
Publication Date: 2019.07.17 CONTINENTAL TEVES AG & CO OHG
  • EP2387521B1 patent drawingFigure 1
  • EP2387521B1 patent drawingFigure 2
  • EP2387521B1 patent drawingFigure 3

AI summary

The invention relates to a "brake-by-wire" type braking system for a motor vehicle, comprising a brake pressure transducer which can be actuated by means of a brake pedal of a pedal unit and can be connected to wheel brakes of the vehicle outside of the "brake-by-wire" operating mode, comprising a pressure source which can be controlled by means of an electronic control unit and can be connected to the wheel brakes of the vehicle in the "brake-by-wire" operating mode, comprising means for detecting a deceleration request of a driver, and further comprising a pedal travel simulator which interacts with the brake pedal and is formed by at least one simulator element and by means of which a restoring force acting on the brake pedal in the "brake-by-wire" operating mode can be simulated independently of the control of the pressure source. In order to provide a simpler and more cost-effective "brake-by-wire" type braking system, according to the invention a force-distance characteristic of the pedal travel simulator 2 is controllable.