Fuel Injection Valve Support Ring and Plastic Overmolding

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Solution Overview

Problem

Existing fuel injection valves face challenges in maintaining effective sealing and minimizing vibration-induced noise, particularly in long valves with large axial lengths, where additional metallic extensions and weld seams are required, increasing manufacturing costs and risk of noise transmission.

Innovation Solution

A fuel injection valve design featuring a support ring that engages under the inlet side sealing ring, resting on a plastic overmolding with a conically oblique upper end face, providing indirect axial support and a V-shaped contact surface to prevent radial gaps and ensure secure sealing without metallic contact, thus eliminating vibration transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If additional metallic extensions are used to increase axial length, then the valve can achieve required installation length, but manufacturing costs increase and noise transmission risk increases

Engineering Contradiction:

Improveaxial lengthVSAvoidmanufacturing costs

Core Design Contradiction:

Length of moving objectVSEase of manufacture

Solution Approach 1:

The patent employs a composite structure combining metal inlet connection with plastic overmolding material. The plastic material extends the axial length of the valve body without requiring additional metallic extensions, thereby reducing manufacturing costs while avoiding noise transmission associated with metallic components.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameter from purely metallic to a composite of metal and plastic overmolding. This parameter change allows the plastic material to provide the necessary axial length extension while eliminating the need for additional metal parts and weld seams, thus reducing manufacturing complexity and cost.

Inventive Principle:

Principle #35Parameter changes

2Length of moving object

If additional metallic extensions and weld seams are used, then axial length requirements are met, but noise transmission increases

Engineering Contradiction:

Improveaxial lengthVSAvoidnoise transmission

Core Design Contradiction:

Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The plastic overmolding acts as an intermediary material between the metal inlet connection and the external environment. This plastic intermediary prevents direct metallic contact and vibration transmission, thereby eliminating noise transmission while still providing the required axial length extension.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces expensive and noise-prone metallic extensions with a cost-effective plastic overmolding material. The plastic material achieves the same functional purpose of length extension without the harmful noise transmission properties of metal.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If the support ring is made larger radially, then sealing reliability improves, but assembly difficulty increases due to radial pressing requirements

Engineering Contradiction:

Improvesealing reliabilityVSAvoidassembly difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The support ring is designed with a dynamic characteristic where it can be compressed radially during assembly to pass through tight spaces, then expands to its full radial size to provide effective sealing. This dynamic behavior allows the ring to be both compact during assembly and large during operation, resolving the contradiction between assembly ease and sealing reliability.

Inventive Principle:

Principle #15Dynamics

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 design enhances sealing efficiency, reduces manufacturing costs by avoiding additional metallic extensions, and minimizes noise by preventing metallic contact and vibration transmission, even under increased pressures and potential creep of plastic components.

Implementation Method 1

This prevents the sealing ring from extruding between the support ring and the walls of the receiving opening or the connecting piece, because no undesirable gaps are able to form

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

As a result of the fluid pressure, two force components act via the sealing ring on the two flanks of the V-shaped contact surface of the support ring

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 3

These forces cause a slight elastic deformation of the support ring, specifically in the thin-walled regions radially on the inside and on the outside below the contact surface

Methodology Applied

Scientific EffectForce decomposition: Mechanical Force

Data Source

PatentUS20230332568A1Fuel injection valve

Publication Date: 2023.10.19 ROBERT BOSCH GMBH

AI summary

A fuel injection valve. The fuel injection valve has a support ring is provided on an inlet connection, which engages under the sealing ring on the inlet side. A plastic overmolding forms at least part of a valve housing. The support ring engaging under the sealing ring is positioned on the fuel injection valve in such a way that it rests directly on an upper end face of the plastic overmolding facing the sealing ring, so that the axial support of the sealing ring is provided indirectly via the plastic overmolding. The fuel injection valve is suitable, in particular, for the direct injection of fuel into a combustion chamber of a mixture-compressing external spark-ignition combustion engine.