DC Arc Detection Circuit for Vehicle Wiring Harness Protection

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Solution Overview

Problem

Existing arc suppression techniques in automotive applications face performance limitations, high costs, complexity, and durability issues, making them ineffective in preventing undesired arcing in electrical components and wiring.

Innovation Solution

A circuit is designed to detect DC arcing conditions and divert arcing energy using a capacitor, resistor, and diode configuration, coupled with a Field Effect Transistor (FET) or Silicon Controlled Rectifier (SCR) to shunt the arc energy, reducing power consumption and enhancing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional arc suppression techniques are used, then arc suppression capability is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvearc suppression capabilityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The circuit uses the arc-induced voltage spike itself as the trigger signal to activate the FET, eliminating the need for separate arc detection sensors or control circuits. The capacitor automatically charges during normal operation and discharges through the FET when an arc occurs, creating a self-regulating suppression system that reduces overall device complexity while maintaining effective arc suppression capability.

Inventive Principle:
Principle #25Self-service

2Reliability

If traditional arc suppression techniques are used, then arc suppression capability is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvearc suppression capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The circuit employs inexpensive, readily available components including a standard FET, capacitor, and diode that can be easily manufactured and replaced. These simple electronic components are significantly cheaper than complex mechanical arc suppression devices or specialized suppression circuits, enabling cost-effective mass production while providing reliable arc suppression protection.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If continuous monitoring for arc detection is implemented, then detection precision improves, but energy consumption increases

Engineering Contradiction:
Improvearc detection precisionVSAvoidcircuit power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of continuous monitoring, the circuit uses periodic passive charging of the capacitor during normal operation and only activates actively when an arc event occurs. The FET remains in high-impedance state during normal conditions, consuming minimal power, and only conducts when the capacitor voltage reaches the trigger threshold during an arc, achieving precise arc detection with negligible steady-state power consumption.

Inventive Principle:
Principle #19Periodic action

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 provides a 50% improvement in performance and a 70% reduction in manufacturing costs, effectively suppressing arcing and protecting automotive wire harness components by actively managing arcing energy during contact transitions.

Implementation Method 1

A capacitor is connected in parallel with the protected component

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

A diode is connected in series between the capacitor and the FET gate

Methodology Applied
Scientific EffectDiode effect: Diode

Implementation Method 3

The switching circuit includes a solid state triggerable switch that is configured to receive the control signal from the detector circuit, and upon receipt of the control signal, to conduct electricity from the input terminal to the output terminal

Methodology Applied
Scientific EffectField Effect Transistor conduction:

Implementation Method 4

An electric arc (also known as an arc discharge) is an electrical breakdown of a gas that produces an ongoing electrical discharge. Current passing through a medium produces plasma, which may generate visible light.

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 5

Current passing through a medium produces plasma, which may generate visible light

Methodology Applied
Scientific EffectPlasma: Plasma

Data Source

PatentEP3550581B1Methods and apparatus for DC arc detection/suppression
Publication Date: 2024.02.07 YAZAKI NORTH AMERICA INC
  • EP3550581B1 patent drawingFigure 1
  • EP3550581B1 patent drawingFigure 2
  • EP3550581B1 patent drawingFigure 3

AI summary

Some embodiments are directed to an apparatus for detecting and suppressing DC electric arcs at a component, and are particularly adapted for vehicle wiring harnesses. The apparatus can include a detector circuit electrically connected to input and output terminals so as to be electrically connected in parallel to the component, the detector circuit being configured to detect a significant voltage spike across the component upon the component actuating between open and closed positions. The detector circuit can also be configured to transmit a control signal upon detecting the significant voltage spike. The detector circuit can include multiple circuit elements, enabling both the detection of the significant voltage spike and the transmission of the control signal, that are directly electrically connected to each other. A switching circuit conducts electricity from the power source side of the component to the load side of the component upon receipt of the control signal.