Fuel Injector Seal Supporting Ring with Radial Opening

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Solution Overview

Problem

Existing fuel injectors for internal combustion engines face issues with sealing element deformation under high pressure, leading to undefined leakage cross-sections and increased risk of extrusion, which affects sealing efficiency and tolerance handling.

Innovation Solution

The design incorporates a support ring with radially inner and outer sealing surfaces and strategically placed openings, positioned centrally within the support ring, to maintain a defined leakage cross-sectional area and reduce the risk of extrusion by aligning the leakage areas radially inward, away from the edge, thus minimizing deformation impact on sealing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the support ring has edge regions close to the sealing ring, then the sealing effect is improved, but the support ring undergoes plastic deformation under high pressure making the leakage cross-section undefined

Engineering Contradiction:
Improvesealing effectVSAvoidleakage cross-section definition
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The support ring is segmented by introducing at least one opening that extends through the radial thickness, dividing the support ring structure into separate sections. This segmentation prevents continuous plastic deformation across the entire support ring while maintaining localized sealing contact regions, thus preserving both sealing effectiveness and dimensional stability of the leakage cross-section.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The opening is positioned at a specific radial distance from the edge regions to create different functional zones: the edge regions maintain close proximity to the sealing ring for effective sealing, while the opening region provides stress relief to prevent deformation. This local differentiation of structural properties resolves the contradiction between sealing effectiveness and dimensional precision.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the sealing ring is made flexible to accommodate pressure variations, then adaptability is improved, but the risk of extrusion increases

Engineering Contradiction:
Improvepressure accommodationVSAvoidextrusion risk
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The opening in the support ring acts as an intermediary structure that allows controlled fuel penetration into the radial gap between the sealing ring and support ring. This controlled penetration reduces shear load on the sealing ring material without compromising the flexible sealing contact, thereby mitigating extrusion risk while preserving pressure accommodation capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stress or pressure

If the opening is placed in the edge region of the support ring, then stress relief is improved, but the leakage area becomes sensitive to micro-movements

Engineering Contradiction:
Improvepressure reliefVSAvoidleakage area stability
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The opening is positioned at an optimized radial distance from the edge region, creating distinct functional zones: the edge regions maintain stability for reliable leakage area definition, while the opening provides stress relief. This local differentiation ensures that micro-movements do not significantly affect the leakage area while pressure relief is effectively provided.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP1941152B1Injector having a seal and supporting ring
Publication Date: 2010.04.07 ROBERT BOSCH GMBH
  • EP1941152B1 patent drawingFigure 1~2
  • EP1941152B1 patent drawingFigure 3~4
  • EP1941152B1 patent drawingFigure 5a~5d

AI summary

The invention relates to an injector, in particular for injecting fuel into a combustion chamber of an internal combustion engine, having a valve element which can be displaced longitudinally in a valve housing and an annular pressure chamber which is formed between the valve housing and the valve element and has a sealing element which is arranged therein between the valve housing and the valve element, wherein the sealing element has a sealing ring and an associated supporting ring (30), and the sealing ring has a radially inwardly lying sealing face and a radially outwardly lying sealing face, characterized in that the supporting ring (30) has at least one opening (31) which is spaced apart from a radially inner and a radially outer edge region (30A, 30B) of the supporting ring (30) (figure 5a).