Helical Nozzle Needle Guide for Fuel Injector Stability

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Solution Overview

Problem

Existing nozzle needles for fuel injectors lack stability and efficient production methods, leading to potential deflection during stroke movements and increased production costs.

Innovation Solution

A nozzle needle design featuring helically guided surfaces and involute toothing, allowing for improved support and fuel flow, produced through cold forming and low-cost machining processes, which reduces cycle time and production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional guide surfaces are used in the nozzle needle, then the structure is simple to manufacture, but the nozzle needle stability is insufficient and deflection occurs during stroke movement

Engineering Contradiction:
Improvenozzle needle stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The guide surfaces are designed with helical curvature around the longitudinal axis of the nozzle needle, replacing traditional flat or simple curved surfaces. This helical geometry provides continuous contact with the nozzle body inner surface, distributing support forces evenly and preventing lateral deflection during stroke movement, thereby significantly improving nozzle needle stability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The guide surfaces extend in the axial direction along the nozzle needle stroke movement path, adding a dimensional element that traditional radial guide surfaces lack. This axial extension creates a more comprehensive contact zone with the nozzle body, providing continuous guidance and support throughout the entire stroke movement, which enhances stability without significantly complicating the manufacturing process.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If multiple guide surfaces are added to improve stability, then nozzle needle support is enhanced, but production costs and manufacturing complexity increase

Engineering Contradiction:
Improvenozzle needle supportVSAvoidguide section complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The guide section is divided into multiple discrete guide surfaces arranged helically around the nozzle needle. Each guide surface acts as an independent support element, and their distributed arrangement provides comprehensive stability without requiring a single complex guiding structure. This segmentation allows for modular manufacturing and assembly, controlling overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide surfaces serve multiple functions simultaneously: they provide lateral support to prevent deflection, guide the nozzle needle during stroke movement, and maintain proper alignment with the nozzle body. This multi-functionality reduces the need for separate components, thereby enhancing support while controlling device complexity and production costs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If the guide section is designed with helical guide surfaces, then nozzle needle stability is improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvenozzle needle stabilizationVSAvoidguide surface precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The helical curvature of the guide surfaces can be manufactured using standard cylindrical grinding or turning operations with appropriate toolpath programming. The helical geometry, while appearing complex, follows regular mathematical patterns that are well-suited to conventional CNC machining, allowing for precise replication without requiring specialized manufacturing equipment or processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design enhances the stability of the nozzle needle by minimizing axial deflection and reducing pressure on fuel delivery, while enabling cost-effective mass production through efficient manufacturing processes.

Implementation Method 1

The guide surface is designed to abut an inner surface of a nozzle body of the injector

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The guide surface is helically guided around the longitudinal axis of the nozzle needle, so that improved support of the nozzle needle is provided within the nozzle body of the injector. Furthermore, the deaxialization due to the helical design of the guide surface and the offset relative to possible other guide sections are minimized.

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 3

The recess is designed to allow fuel to flow along the guide section of the nozzle needle

Methodology Applied
Scientific EffectFluid Flow:

Implementation Method 4

the guide section is introduced into the nozzle needle by means of cold forming, in particular by means of the rolling manufacturing method

Methodology Applied
Scientific EffectCold-forming: Cold-forming

Implementation Method 5

The body of the nozzle needle is tempered and then at least the guide surfaces are hard-machined, in particular hard-turned or ground

Methodology Applied
Scientific EffectHeat Treatment: Heat Treatment

Data Source

PatentEP2771563B1Nozzle needle for an injector for injecting fuel into cylinder combustion chambers of an internal combustion engine, and an injector comprising such a nozzle needle
Publication Date: 2022.04.06 VITESCO TECHNOLOGIES GMBH
  • EP2771563B1 patent drawingFigure 1
  • EP2771563B1 patent drawingFigure 2
  • EP2771563B1 patent drawingFigure 3

AI summary

The invention relates to a nozzle needle (1) and an injector (2) comprising such a nozzle needle (1), as well as to a production method for producing said nozzle needle (1). This nozzle needle (1) for an injector (2) for injecting fuel comprises at least one guiding section (11, 13) with a recess (21) and a guiding surface (14, 15, 16) designed to rest against an inner surface (30) of a nozzle body (3) of the injector (2), said recess (21) at least partially delimiting the guiding surface (14, 15, 16) and being designed to allow a flow of fuel along the guiding section (11, 13), and said guiding surface (14, 15, 16) being guided about the longitudinal axis (10) of the nozzle needle (1) in a helical manner.