Brake Light Control Device with Hardware Backup Controller

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Solution Overview

Problem

Conventional vehicles rely on mechanical brake light switches for brake light control, which can fail in hybrid and electric vehicles during engine start or gear changes, leading to potential breakdowns, especially when software solutions are unavailable.

Innovation Solution

A device comprising a brake pedal sensor, main controller, and backup controller, where the main controller monitors and conditions the brake pedal signal to control braking and activate the brake lights, and the backup controller provides a hardware-based alternative signal to ensure reliable brake light activation in case of main controller failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a software-based brake control system is used in hybrid and electric vehicles, then recuperation efficiency and braking control are improved, but system reliability deteriorates when software is unavailable during engine start or gear changes

Engineering Contradiction:
Improvebrake light control reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a backup controller that is pre-configured with simple brake light control logic, standing by to take over immediately if the main software-based controller fails. This beforehand preparation ensures continuous reliable operation without requiring complex real-time decision-making during failure scenarios.

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

Solution Approach 2:

The patent replaces the traditional mechanical brake light switch with an electronic sensor-based system that provides continuous brake pedal position signals to both the main software controller and the backup controller, enabling more precise and reliable brake light activation control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If a mechanical brake light switch is used, then system simplicity is maintained, but system availability deteriorates during engine start or gear change operations

Engineering Contradiction:
Improvecontrol system complexityVSAvoidsystem availability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The brake pedal sensor serves multiple functions: it provides signals for the main software-based brake control system, supplies input to the backup controller for brake light activation, and enables security queries during engine start and gear changes. This multi-functionality eliminates the need for separate mechanical switches while improving availability.

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

Solution Approach 2:

The backup controller acts as an intermediary component that receives brake pedal signals independently from the main software system and directly controls brake light activation. This intermediary ensures brake light functionality remains available even when the main software system is unavailable during critical operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If redundant sensors and plausibility checks are implemented, then brake control reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvebrake control reliabilityVSAvoidsensor and control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a simplified copy of the brake control function in the backup controller that mirrors the essential brake light activation logic. This copy uses the same brake pedal sensor input but implements a simpler control algorithm, providing redundancy without requiring duplicate complex sensor systems or extensive plausibility check infrastructure.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2771209B1Device for controlling a brake light in a motor vehicle
Publication Date: 2015.08.12 ROBERT BOSCH GMBH
  • EP2771209B1 patent drawingFigure 1~2
  • EP2771209B1 patent drawingFigure 3

AI summary

A device (1) for controlling a brake light (21) of a motor vehicle is described. The device comprises a brake pedal sensor (5), a main control device (11) and a reserve control device (13). The brake pedal sensor (5) outputs a brake pedal signal which is dependent on an activation intensity of a brake pedal (3). The main control device (11) conditions and monitors the brake pedal signal and generates a brake control signal for controlling a braking process. In addition, the main control device (11) generates a brake pedal activation signal for controlling activation of the brake light. While the main control device (11) can be implemented by means of software in some of its functions, the reserve control device (13) is implemented exclusively by means of hardware and uses a comparator (25) to carry out a comparison between a brake pedal signal conditioned with a component (23) and switch-on and switch-off thresholds for the activation of the brake light. With the device proposed it is possible to dispense with conventionally used brake light switches and at the same time to ensure that even in the case of a defect in the main control device (11) a brake pedal activation signal is reliably generated which can both correctly activate the brake light (21) and prevent the vehicle from becoming stranded.