Rotatable Electrode Spark Plug for Swirl Chamber

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Solution Overview

Problem

Existing swirl chamber spark plugs for large gas engines have non-adjustable electrode gaps, leading to excessive use of precious metals and high manufacturing costs, with limited service life and a poor cost-benefit ratio.

Innovation Solution

A spark plug design where the center and ground electrodes can be rotated relative to each other, allowing adjustable spark surface gaps, reducing the need for large noble metal surfaces and enabling cost-effective manufacturing while extending service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the noble metal surfaces of the electrodes are made as large as possible to ensure reliable sparking, then the service life and reliability of the spark plug are improved, but the manufacturing costs increase significantly due to excessive use of expensive precious metals

Engineering Contradiction:
Improveservice life of spark plugVSAvoidamount of noble metal used
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention makes the electrode gap adjustable by allowing relative rotation between the center electrode and ground electrode through threaded connections. This dynamic adjustment capability enables optimization of the spark gap distance to achieve reliable sparking with smaller noble metal surfaces, resolving the contradiction between reliability and material consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the fixed parameter of electrode gap distance into a variable parameter that can be adjusted by rotating the center electrode or ground electrode. By adjusting the gap distance parameter, the system achieves optimal sparking performance with reduced noble metal surface area, addressing the contradiction between reliability and cost.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the electrode gap is fixed in the design, then the manufacturing process is simplified, but the spark plug cannot be adapted to different operating conditions and its service life is limited

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidadjustability of spark gap
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention introduces adjustability through threaded connections that allow relative rotation between electrodes. This dynamic feature enables gap adjustment without complicating the manufacturing process, as the threaded structure is integrated into the electrode assembly design, resolving the contradiction between manufacturing simplicity and adaptability.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the cap closes off the swirl chamber completely, then the combustion chamber is properly sealed, but access to the electrodes for adjusting the spark gap is blocked

Engineering Contradiction:
Improvesealing of combustion chamberVSAvoidaccessibility of electrodes
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention segments the cap structure into a main body that provides sealing and an adjustable section that allows access to the electrodes. The cap includes a through-opening or access path that enables tool insertion for adjusting the spark gap while maintaining the sealed combustion chamber, resolving the contradiction between sealing reliability and operational accessibility.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2815472B1Spark plug, particularly for swirl chamber
Publication Date: 2019.03.27 ROBERT BOSCH GMBH
  • EP2815472B1 patent drawingFigure 1~2
  • EP2815472B1 patent drawingFigure 3~4
  • EP2815472B1 patent drawingFigure 5~6

AI summary

The present invention relates to a spark plug (1) comprising a central electrode (3) extending along a longitudinal axis (2) of the spark plug (1) and having at least one first spark face (6), and a ground electrode (4) having at least one second spark face (8), wherein the first spark face (6) is arranged opposite the second spark face (8), with the result that an ignition spark can be generated between the first spark face (6) and the second spark face (8), wherein the central electrode (3) is rotatable with respect to the ground electrode (4) coaxially to the longitudinal axis (2), and/or the ground electrode (4) is rotatable with respect to the central electrode (3) coaxially to the longitudinal axis (2), and wherein the first spark face (6) and the second spark face (7) are inclined in such a way that, by rotation of the central electrode (3) with respect to the ground electrode (4) and/or of the ground electrode (4) with respect to the central electrode (3), a distance (18) between the first spark face (6) and the second spark face (8) is adjustable.