Trailer Brake ECU Firewall for CAN Bus Integration

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Solution Overview

Problem

The increasing complexity and cost of trailer brake systems due to additional electrical and pneumatic connections for advanced functionalities, along with the need for separate CAN buses to segregate safety-critical and auxiliary systems, lead to space constraints and reliability issues.

Innovation Solution

A brake system with an electro-pneumatic module that acts as a firewall between different communication buses, allowing third-party devices to connect without requiring safety standard testing, by using a third standards-compliant CAN HD bus for auxiliary functionality and ensuring data integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional electrical and pneumatic connections are added for advanced functionalities, then the functionality and versatility of the brake system is improved, but the cost and device complexity increase

Engineering Contradiction:
ImprovefunctionalityVSAvoidcomplexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the CAN HD interface and the firewall function into a single integrated module, eliminating the need for separate connections and reducing overall system complexity while maintaining advanced functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated module serves multiple functions: it provides CAN HD communication capability, acts as a firewall between different network domains, and enables auxiliary functionality all through a single component, improving versatility without proportionally increasing complexity

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

2Reliability

If separate CAN buses are used to segregate safety-critical and auxiliary systems, then the reliability and safety of the brake system is improved, but the device complexity and space requirements increase

Engineering Contradiction:
ImprovesafetyVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The firewall acts as an intermediary component between the safety-critical CAN bus and the auxiliary CAN bus, allowing controlled communication while maintaining isolation. This enables reliable segregation of safety systems without requiring completely separate physical buses for all functions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system segments communication into different domains (safety-critical and auxiliary) with controlled interfaces, allowing each segment to be optimized independently while reducing overall complexity compared to fully separate systems

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If third-party devices are connected to the CAN bus, then the adaptability and versatility of the system is improved, but the reliability and safety of the brake system may be compromised

Engineering Contradiction:
ImproveadaptabilityVSAvoidsafety
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The firewall serves as an intermediary that mediates all communication between third-party devices on the auxiliary bus and the safety-critical brake control systems. It filters and validates data packets, blocking potentially harmful communications while allowing legitimate auxiliary functions to operate

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The firewall provides beforehand protection by pre-establishing security rules and filtering mechanisms that prevent harmful data from reaching safety-critical systems, cushioning the brake control against potential failures or malicious inputs from third-party devices

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

Data Source

PatentEP3261889B1Trailer brake system
Publication Date: 2021.08.04 KNORR BREMSE SYST FOR COMML VEHICLES LTD
  • EP3261889B1 patent drawingFigure 1
  • EP3261889B1 patent drawingFigure 2
  • EP3261889B1 patent drawingFigure 3

AI summary

Trailer brake system with a braking ECU, which is connected to a standards compliant communication bus on the trailer and is adapted to receive data inputs from sensors on the trailer and control a first pressure modulator. The brake system further comprises an electro pneumatic module, which receives further data inputs relating to auxiliary functionality from sensors on the trailer via a second standards compliant communication bus. The electropneumatic module is connected to the braking ECU via a third standards compliant communication bus.