Cable Strand Filter for Common-Rail Injection EMI Reduction

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Solution Overview

Problem

Existing cable strands for common-rail injection systems in internal combustion engines face challenges in minimizing electromagnetic interference radiation, particularly in commercial vehicles, due to high-frequency actuation peaks and steep signal amplitudes, which are costly to address through conventional shielding or engine control system modifications.

Innovation Solution

Integration of a filter arrangement within the cable strand, molded or foamed into a polymeric carrier, which includes a filter support with inductors and capacitors to minimize electromagnetic interference, and a mounting system that connects the filter support to the engine control device for effective grounding without additional expense.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a metallic shielding is added to the cable strand to block interference radiation, then electromagnetic compatibility is improved, but manufacturing cost and complexity increase significantly

Engineering Contradiction:

Improveelectromagnetic interference radiationVSAvoidcable strand structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The filtering function is extracted from the cable strand structure and implemented as a separate filter circuit integrated into the engine control device. This eliminates the need for metallic shielding in the cable strand while still addressing electromagnetic interference through passive filter circuits at the control unit outputs.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Passive filter circuits serve as intermediary elements between the engine control device outputs and the cable strand connections. These filter circuits prevent actuation peaks from passing to the cable connections, thereby reducing interference radiation without requiring modification of the cable strand itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If metallic shielding is integrated into the cable strand, then electromagnetic compatibility is improved, but production cost increases due to additional materials and assembly steps

Engineering Contradiction:

Improveinterference radiationVSAvoidcable strand production

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The electromagnetic filtering function is extracted from the cable strand manufacturing process and relocated to the engine control device. This eliminates the need for metallic shielding materials and associated assembly steps in cable strand production, thereby maintaining ease of manufacture while still addressing interference radiation through filter circuits integrated into the control unit.

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If the engine control system is modified to reduce interference, then electromagnetic compatibility is improved, but development cost and complexity increase

Engineering Contradiction:

Improveinterference radiationVSAvoidengine control system

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The engine control system is segmented into functional modules, with passive filter circuits integrated into the output stage. This segmentation allows the filter circuits to be added as a discrete component without requiring comprehensive modification of the entire control system, thereby limiting the increase in device complexity to a specific functional area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Passive filter circuits are integrated into the output stage of the engine control device to modify the electrical parameters of actuation signals. This approach addresses interference radiation by filtering high-frequency actuation peaks while maintaining the core control system architecture, thereby limiting complexity increase to the addition of filter components rather than comprehensive system redesign.

Inventive Principle:

Principle #35Parameter changes

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 electromagnetic interference radiation effectively while maintaining media resistance and mechanical protection, optimizing electromagnetic compatibility without the need for extensive modifications or increased costs, especially in small-scale production.

Implementation Method 1

at least one filter that is also molded and/or foamed in the cable strand, wherein the filter is adapted to affect the electromagnetic compatibility of the cable strand arrangement

Methodology Applied

Scientific EffectElectromagnetic filtering: Filter (electronic)

Implementation Method 2

the filter arrangement... includes a filter support with inductors and capacitors to minimize electromagnetic interference

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS8269573B2Cable strand for activating ejection valves

Publication Date: 2012.09.18 MAN TRUCK & BUS SE

AI summary

A cable strand for the activation of electrically actuatable injection valves of internal combustion engines having a common-rail injection system, wherein the cable strand connects an engine control device with the injection valves. Electrical cables of the cable strand are molded and/or foamed in a carrier that largely prescribes the shape of the cable strand. At least one filter is also molded and/or foamed in the cable strand and is adapted to affect the electromagnetic compatibility of the cable strand arrangement.