Fuel Injector Needle Suspension Reduces Seat Wear

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Solution Overview

Problem

Fuel injector nozzle seat wear leads to performance drift and potential missed injections due to high velocity impacts and altered hydraulic forces, with existing solutions either increasing production costs or compromising injector performance.

Innovation Solution

A hydraulic suspension needle arrangement divides the needle into a main portion and a separate tip portion, with a spring between them, reducing impact momentum and minimizing seat wear by using a pressure chamber and orifices to control damping and movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the needle closes quickly to meet injector delivery requirements, then injection speed and productivity are improved, but seat wear increases due to high velocity impact

Engineering Contradiction:

Improveinjection speedVSAvoidseat wear

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The needle is divided into two separate portions: a needle main portion and a needle tip portion. The needle tip portion (with mass of 0.1-1g) impacts the valve seat to maintain fast closing speed, while the needle main portion (with mass of 1-10g) is decelerated by spring force, preventing high-velocity impact and reducing seat wear.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A spring is positioned between the needle main portion and tip portion to provide cushioning force. The spring decelerates the needle main portion before it can impact the seat, reducing the impact momentum while allowing the lighter tip portion to complete the fast closing action.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Duration of action of stationary object

If material hardening processes are applied to suppress seat wear, then seat durability is improved, but production costs increase

Engineering Contradiction:

Improveseat durabilityVSAvoidproduction cost

Core Design Contradiction:

Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The patent replaces material hardening processes (thermal/nitriding treatment and DLC coating) with a mechanical solution - the hydraulic suspension needle arrangement. This substitutes expensive material treatment with a mechanically engineered needle structure that inherently reduces impact wear.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Duration of action of stationary object

If the needle closes slower to minimize seat wear, then seat durability is improved, but injector performance deteriorates

Engineering Contradiction:

Improveseat durabilityVSAvoidinjector performance

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

By segmenting the needle into main portion and tip portion, the system achieves differential motion: the tip portion maintains fast closing for performance, while the main portion slows down to protect the seat, resolving the contradiction between speed and durability.

Inventive Principle:

Principle #1Segmentation

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 solution effectively reduces nozzle seat wear while maintaining injector performance by decelerating the needle main portion with spring force, minimizing wear and maintaining efficient fuel injection.

Implementation Method 1

having spring means located between main portion and tip portion

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

reducing impact momentum and minimizing seat wear

Methodology Applied

Scientific EffectImpact momentum reduction: Inertia

Implementation Method 3

the proximal portion of said needle tip and said recess form a pressure chamber

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 4

the distal end of the needle main portion includes at least one orifice or flow channel fluidly connecting said pressure chamber to said nozzle body volume

Methodology Applied

Scientific EffectFluid flow through orifices: Pressure Drop

Data Source

PatentEP3411589B1Fuel injector nozzle and needle arrangement

Publication Date: 2019.10.23 DELPHI TECH IP LTD

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AI summary

A nozzle arrangement for a fuel injector including a nozzle body having a longitudinal axis, and including a valve seat located towards the distal end thereof, and housing a needle located within said nozzle body and wherein said nozzle body and said needle define a nozzle body volume at the distal end of said nozzle, said needle adapted to be slidable within said nozzle body along said axis, to a closed position where the tip of the needle is in contact with the valve seat, and an open position where the needle tip is in a position away form said valve seat, characterized wherein said needle comprises a needle main portion and a separate needle tip portion, said needle main portion including a recess located at its distal end for location of said needle tip portion, and having spring means located between main portion and tip portion, said tip portion adapted to move along said axis relative to said needle main portion, wherein the proximal portion of said needle tip and said recess form a pressure chamber, and wherein the distal end of the needle main portion includes at least one orifice or flow channel fluidly connecting said pressure chamber to said nozzle body volume.