Redundant ECU Communication Isolation Against Overvoltage Propagation

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Solution Overview

Problem

Existing redundant processing systems in vehicles face the risk of consecutive failures of multiple processing units due to overvoltage propagation through communicably connected CPUs, leading to potential system-wide malfunctions.

Innovation Solution

Incorporating a pair of physical layer devices and a capacitor in the communication line between redundant processing units, utilizing AC coupling to electrically isolate the units and prevent overvoltage propagation, thereby maintaining communication while avoiding simultaneous failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If redundant processing units are communicably connected to enable communication, then communication functionality is achieved, but overvoltage propagation risk increases leading to potential consecutive failures

Engineering Contradiction:

Improvecommunication functionalityVSAvoidconsecutive failure risk

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

A capacitor is introduced as an intermediary component in the communication line between redundant processing units. The capacitor provides AC coupling that enables signal transmission while blocking DC overvoltage propagation, thus serving as a mediator that allows communication functionality while preventing harmful overvoltage from causing consecutive failures

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The communication line is segmented into isolated sections by inserting capacitors between redundant processing units. This segmentation electrically isolates each processing unit while maintaining communication capability through AC coupling, preventing overvoltage from propagating across the entire system

Inventive Principle:

Principle #1Segmentation

2Reliability

If processing units are electrically isolated to prevent overvoltage propagation, then reliability against consecutive failures is improved, but communication capability may be degraded

Engineering Contradiction:

Improveprotection against overvoltage propagationVSAvoidcommunication capability

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The electrical parameters of the communication line are changed by introducing capacitors that allow AC signals to pass while blocking DC components. This parameter change enables the system to maintain communication capability for signal transmission while providing electrical isolation to prevent overvoltage propagation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Capacitors serve as intermediary components that reconcile the contradiction between electrical isolation and communication capability. They mediate by allowing desired AC communication signals to pass while blocking harmful DC overvoltage, thus maintaining both reliability and communication function

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively prevents consecutive failures of redundant processing units by isolating them electrically, ensuring continued operation and control functionality even if one unit fails.

Implementation Method 1

a capacitor that is disposed between the pair of physical layer devices on the communication line and is configured to electrically isolate the first processing unit and the second processing unit from each other by AC coupling

Methodology Applied

Scientific EffectAC coupling: Capacitance

Data Source

PatentUS12420813B2Electronic control unit

Publication Date: 2025.09.23 DENSO CORP

AI summary

An electronic control unit includes: a first processing unit that is configured to execute predetermined arithmetic processing and generate a first control signal for controlling the vehicle; a second processing unit that is redundantly disposed with the first processing unit and is configured to generate a second control signal for controlling the vehicle; a first power supply circuit that is configured to generate power for operating the first processing unit based on power supplied from a first power supply device mounted in the vehicle; a second power supply circuit that is configured to generate power for operating the second processing unit based on power supplied from a second power supply device mounted in the vehicle; and a communication line that communicably connects the first processing unit and the second processing unit to each other. The communication line includes a pair of physical layer devices and a capacitor.