Fuel Injector Needle Axial Alignment via Extraction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing fuel injectors for internal-combustion engines face issues with irregular wear and high production costs due to the need for precise intermediate elements to ensure axial alignment, leading to faster deterioration and increased complexity.

Innovation Solution

A fuel injector design utilizing a perforated intermediate member with a bushing that has an external diameter smaller than the needle, allowing direct engagement and reducing the need for precise adjustments, thus simplifying production and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an intermediate element is used between the rod and the needle to enable adjustment of axial dimensions, then the adjustability and versatility of the injector are improved, but the intermediate element causes transverse components of force that lead to irregular wear and faster deterioration

Engineering Contradiction:

Improveadjustability of axial dimensionsVSAvoidwear resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The invention extracts and eliminates the problematic intermediate element from the system. By establishing direct engagement between the rod and the needle's conical depression, the source of transverse forces and irregular wear is removed, while the desired axial adjustment capability is maintained through direct modification of the needle-rod interface geometry.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using an intermediate element to achieve adjustment, the invention inverts the approach by making the needle itself (through its conical depression) the direct interface with the rod. This reversal eliminates the intermediate component that caused wear problems while preserving the adjustment function through geometric design of the conical engagement surfaces.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If the intermediate element is made with very high precision to limit transverse components, then the reliability and wear resistance are improved, but the manufacturing cost and complexity increase

Engineering Contradiction:

Improvewear resistanceVSAvoidprecision requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention removes the intermediate element entirely, eliminating the need for high-precision manufacturing of such a component. The direct engagement between rod and needle simplifies the system, reducing manufacturing complexity while maintaining reliability through proper geometric design of the conical depression and rod end surfaces.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If a conical depression with intermediate ball or specially shaped rod end is used to guarantee axial resultant, then the reliability is improved, but the production cost increases

Engineering Contradiction:

Improveaxial alignmentVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention merges the functions of the intermediate element and the rod end into a single direct engagement interface. The conical depression in the needle works directly with the rod end (which may have a complementary conical or spherical shape) to guarantee axial resultant forces, eliminating the need for separate intermediate balls or complex shims, thereby reducing production cost while maintaining reliability.

Inventive Principle:

Principle #5Merging (Combining)

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 reliability and performance by minimizing wear and production costs while maintaining axial alignment, resulting in a more efficient and cost-effective fuel injection system.

Implementation Method 1

a rod for controlling the needle, which is controlled by the fuel under pressure, aided by a compression spring

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

the needle, which is normally pushed into a closing position of the nozzle by the fuel under pressure in a control chamber

Methodology Applied

Scientific EffectPressure: Pressure Increase

Data Source

PatentUS7527210B2Fuel injector for an internal-combustion engine

Publication Date: 2009.05.05 CENTRO RICERCHE FIAT SCPA

AI summary

The fuel injector comprises a hollow casing, fixed on which is a nozzle having a nebulizer for the fuel under pressure, a needle axially mobile for opening and closing the nebulizer by means of a first end thereof, and a control rod, substantially coaxial with the needle and in direct engagement therewith. The needle is normally pushed into a closing position of the nozzle by the fuel under pressure acting on the rod, aided by a compression spring, which acts on the needle through a sleeve that is in axial engagement with a portion of the rod. The sleeve further comprises a surface designed to engage at the front and directly one end of the needle. The spring engages another surface of the sleeve so as to transmit its action directly onto the needle.