Residual Air Split Disc for Fuel Injector Stability

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Solution Overview

Problem

Existing solenoid valves for fuel injectors face issues with armature oscillation and bouncing, and the residual air gap disc design impedes the outflow of the return quantity, leading to suboptimal armature movement due to conflicting requirements between stability and hydraulic performance.

Innovation Solution

A simplified residual air gap disc design made from non-magnetic metal foil, not fixed via a spring plate, is inserted between the magnet core and magnet sleeve, allowing free flow of the return quantity and avoiding deformation with radial slots, ensuring the inner pole of the magnetic coil remains uncovered.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the residual air gap disc is fixed via a spring plate on the armature, then the stability of the armature is improved, but the outflow of the return quantity is impeded

Engineering Contradiction:
Improvearmature stabilityVSAvoidreturn quantity outflow
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The residual air gap disc is extracted from the spring plate mounting location and repositioned to be fixed directly to the magnet armature. This removes the interference with the spring chamber and allows the return quantity to flow freely while maintaining armature stability through direct attachment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The residual air gap disc serves as an intermediary element that is strategically positioned and attached to the magnet armature. It provides the necessary stability function while its repositioned location prevents it from blocking the return quantity flow path through the spring chamber.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the residual air gap disc covers the spring chamber, then the armature stability is improved, but the cross section of the return geometry is reduced

Engineering Contradiction:
Improvearmature stabilityVSAvoidreturn geometry cross section
Core Design Contradiction:
Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

The residual air gap disc is extracted from the spring chamber area and repositioned to be attached to the magnet armature. This removes the obstruction to the return geometry cross section while maintaining the stabilizing function of the disc through its new attachment location.

Inventive Principle:
Principle #2Taking out (Extraction)

3Quantity of substance

If the residual air gap disc is made thin to meet hydraulic requirements, then the hydraulic performance is improved, but the strength and stability are compromised

Engineering Contradiction:
Improvehydraulic flowVSAvoiddisc strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The residual air gap disc is extracted from the spring plate mounting and repositioned to the magnet armature. This allows the disc to be made thin for optimal hydraulic performance while the direct attachment to the magnet armature provides sufficient structural support and stability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 the armature movement by eliminating damping interference, allowing optimal flow of the control or leakage quantity without compromising stability, thus improving the overall performance of the solenoid valve.

Implementation Method 1

held down by a spring plate with the magnet valve spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

follows the movement of the armature

Methodology Applied
Scientific EffectInertia: Inertia

Implementation Method 3

magnet armature with a residual air gap disc made from non-magnetic metal foil

Methodology Applied
Scientific EffectMagnetic force: Magnetic Field

Data Source

PatentEP2409308B1Residual air split disc
Publication Date: 2018.01.10 ROBERT BOSCH GMBH
  • EP2409308B1 patent drawingFigure 1~2
  • EP2409308B1 patent drawingFigure 3

AI summary

The invention relates to a magnetic assembly (10) for activation of a fuel injector. The magnetic assembly (10) comprises a magnetic core (22) and a magnetic sleeve (32) accommodating said magnetic core. A front side (26) of the magnetic core (22) has an anchor (14, 16). A residual air split disc (44) is inserted between the magnetic core (22) and the magnetic sleeve (32).