Residual Air Gap Disc Segmentation for Fuel Injector Handling

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Solution Overview

Problem

Residual air gap disks used in magnet valves for fuel injectors, made of non-magnetic material, are difficult to handle due to their open structure, leading to issues with gripping, wedging, and instability, which affects the precision and reliability of fuel injector assembly.

Innovation Solution

A residual air gap disk with a closed outer circumference and kidney-shaped recesses separated by connecting webs, allowing for easy gripping by vacuum devices and enhanced stability, preventing wedging and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the residual air gap disc is made with large flow cross-section recesses to enable adequate flow of control quantity, then the flow capability is improved, but the handling security deteriorates due to lack of closed surfaces for gripping

Engineering Contradiction:
Improveflow cross sectionVSAvoidhandling security
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The disc is segmented into multiple recesses (first, second, and third recesses) that are distributed across the disc surface. Each recess provides flow pathways while the segmentation allows the remaining material to form closed peripheral portions that can be gripped by handling devices

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the disc have different properties: the recess areas provide flow capability while the closed peripheral portions provide gripping surfaces. The local quality varies between the open recess regions and the closed peripheral regions, optimizing both flow and handling functions

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the residual air gap disc has interrupted circumference with recesses to facilitate flow, then the flow cross section is improved, but the stability deteriorates making the disc susceptible to deformations

Engineering Contradiction:
Improveflow cross sectionVSAvoidresistance to deformation
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The disc is divided into multiple recesses rather than one large opening, and each recess is separated by closed peripheral portions. This segmentation distributes the structural load and prevents excessive deformation while maintaining adequate flow cross-section through each recess

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recesses are designed with specific asymmetric shapes and positions rather than uniform circular openings. This asymmetric arrangement optimizes both the flow characteristics and the structural stability by strategically placing material to resist deformation while maintaining flow pathways

Inventive Principle:
Principle #4Asymmetry

3Ease of operation

If the residual air gap disc has closed peripheral portions for easy handling, then the handling security is improved, but the flow cross section is reduced

Engineering Contradiction:
Improvehandling securityVSAvoidflow cross section
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The disc is segmented into multiple recesses (first, second, third recesses) rather than having a single large opening. This segmentation allows the closed peripheral portions to be sufficient for handling while the combined flow cross-section of all recesses maintains adequate flow capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design transitions from considering only the two-dimensional flow area to incorporating the third dimension of disc thickness and peripheral distribution. The closed peripheral portions extend around the circumference, providing gripping surfaces without significantly reducing the total flow cross-section available through the recesses

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

4Quantity of substance

If the residual air gap disc has multiple recesses spaced apart to release flow, then the flow capability is improved, but the device complexity increases making wedging possible

Engineering Contradiction:
Improveflow cross sectionVSAvoidstructural complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The disc is segmented into a specific number of recesses (three recesses in the preferred embodiment) arranged in a regular pattern around the circumference. This segmentation provides adequate flow cross-section while the regular, simple pattern minimizes structural complexity compared to irregular multi-recess designs

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple functional requirements are merged into the recess design: each recess provides flow pathways, the spaces between recesses provide closed peripheral portions for handling, and the overall arrangement prevents wedging. This merging of functions reduces the need for additional separate features, simplifying the overall structure

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2300702B1Residual air gap disc
Publication Date: 2012.09.26 ROBERT BOSCH GMBH
  • EP2300702B1 patent drawingFigure 1~2

AI summary

The invention relates to a residual air gap disc (10) for magnetic groups of solenoid valves, particularly for actuating fuel injectors. With the residual air gap disc (10), a residual air gap between a front of a magnet core of the magnet group and an armature actuating a valve member is set. The residual air gap disc (10) comprises a substantially closed outer circumference (30). Between a first and a second diameter (44, 46), recesses (40) and closed surface regions (48) are configured in the circumferential direction.