Electromagnetic Fuel Injection Valve Taper Face Segmentation

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Solution Overview

Problem

The existing electromagnetic fuel injection valves experience a sticking phenomenon due to fuel oil films, leading to delays in the detachment of the movable core from the fixed core when the coil is de-energized, which degrades valve-closing responsiveness.

Innovation Solution

The electromagnetic fuel injection valve incorporates a taper face on the movable core with recess parts that divide it into sections along the peripheral direction, reducing engagement area and sectioning fuel oil films, allowing immediate detachment and improving responsiveness, and features a plating layer for enhanced durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the annular projection and taper face engage over the entire periphery to provide self-centering action, then the movable core is maintained coaxial with the fixed core, but a fuel oil film forms in the engaged part causing sticking phenomenon and delaying detachment

Engineering Contradiction:

Improvecoaxial alignment stabilityVSAvoidvalve-closing responsiveness

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The taper face is divided into multiple separate engagement regions by radial grooves, transforming the continuous peripheral engagement into segmented discrete contact points. This segmentation prevents the formation of a continuous fuel oil film while maintaining sufficient engagement area for self-centering action, thereby resolving the contradiction between alignment stability and sticking prevention.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the coil is energized to attract the movable core for valve opening, then the valve body opens for fuel injection, but residual magnetism causes delay in detachment when energization is cut off

Engineering Contradiction:

Improvevalve-opening responsivenessVSAvoiddetachment delay time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The segmented engagement structure reduces the total engagement area between the annular projection and taper face, which in turn reduces residual magnetism in the engaged part. This allows the movable core to detach more quickly from the fixed core when energization is cut off, reducing the detachment delay time while maintaining sufficient engagement for reliable valve opening.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If the engagement area between annular projection and taper face is increased for better self-centering, then coaxial alignment is improved, but the fuel oil film sticking phenomenon is exacerbated

Engineering Contradiction:

Improvecoaxial alignment precisionVSAvoidfuel oil film sticking

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

By dividing the taper face into multiple discrete engagement regions through radial grooves, the design maintains sufficient total engagement area for precise self-centering action while preventing continuous fuel oil film formation. The grooves act as fuel discharge paths, eliminating the harmful sticking effect while preserving alignment precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The radial grooves serve as intermediary structures that disrupt the fuel oil film formation between the annular projection and taper face. These grooves provide fuel discharge paths that prevent the harmful oil film from developing, while the engagement surfaces between the grooves maintain the necessary mechanical engagement for precise alignment.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 suppresses sticking, enhances valve-closing responsiveness, and stabilizes self-centering action, reducing residual magnetism and wear, thereby improving the overall performance and durability of the fuel injection valve.

Implementation Method 1

a coil that is disposed on an outer periphery of the fixed core, a valve body that is formed by a valve part and a rod connected to the valve part that operates in cooperation with the valve seat, a movable core that is fitted around an outer periphery of the rod while making an attracted face of the movable core oppose an attracting face of the fixed core within the valve housing

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an auxiliary spring that exhibits a spring force to move the movable core away from the valve open-side stopper and make the movable core abut against the valve closed-side stopper when the coil is unenergized

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11486343B2Electromagnetic fuel injection valve

Publication Date: 2022.11.01 ASTEMO LTD

AI summary

In an electromagnetic fuel injection valve, a plurality of recess parts are provided in an attracted face of a movable core, the recess parts dividing a taper face of the movable core into a plurality of sections along a peripheral direction of the movable core. Accordingly, a fuel oil film present in an engaged part between an annular projection of a fixed core and the taper face is sectioned at a plurality of locations, thereby suppressing a sticking phenomenon of the engaged part caused by the fuel oil film. Therefore, when energization of a coil is cut off, a delay in detachment of the movable core from the fixed core is eliminated, thus contributing to improvement of valve-closing responsiveness.