Fuel Supply Device Annular Gap Valve Sealing

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Solution Overview

Problem

Combustion engines often experience functional impairments due to unsuitable fuel supply, which can be caused by dirt such as chips accumulating between valve plates and the valve seat, preventing the valve plates from reaching the closed position.

Innovation Solution

A fuel supply facility is designed with a ring gap in the fuel canal where the valve is arranged, with the gap width coordinated to the hub of the valve plates, ensuring it is not larger than the double hub. This configuration prevents dirt from passing through while maintaining flow efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the valve seat and valve plate are in direct contact to ensure sealing, then sealing performance is improved, but contaminants can accumulate between them preventing proper valve closure

Engineering Contradiction:
Improvevalve sealing performanceVSAvoidcontaminant accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An annular gap is introduced as an intermediary space between the valve seat and valve plate. This gap prevents direct contact between the valve components and contaminants, allowing contaminants to be washed away by fuel flow while maintaining proper valve sealing through controlled clearance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the annular gap width is increased to prevent contaminant accumulation, then reliability is improved, but fuel flow efficiency deteriorates

Engineering Contradiction:
Improvevalve operation reliabilityVSAvoidfuel flow rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The annular gap width is optimized to specific parameter ranges (0.01-0.05mm in preferred embodiments) that balance two opposing requirements: wide enough to prevent contaminant accumulation and allow proper valve closure, but narrow enough to minimize impact on fuel flow efficiency.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the annular gap width is decreased to improve fuel flow efficiency, then productivity is improved, but the valve plate cannot reach the closed position due to contaminant obstruction

Engineering Contradiction:
Improvefuel flow efficiencyVSAvoidvalve closure capability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The annular gap is designed with dimensions that are larger than the typical size of fuel contaminants (chips, particles), creating excessive clearance relative to contaminant size. This ensures contaminants cannot bridge the gap to prevent valve closure, while the gap remains narrow enough to maintain fuel flow efficiency.

Inventive Principle:
Principle #16Partial or excessive action

4Reliability

If additional components are added to filter contaminants from the fuel path, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefuel supply reliabilityVSAvoidfuel supply device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The annular gap structure serves multiple functions simultaneously: it acts as a contaminant barrier, maintains fuel flow efficiency, enables proper valve closure, and is integrated into the existing valve seat and valve plate components without requiring separate filter elements or additional parts.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The annular gap is formed by integrating the valve seat and valve plate components themselves, merging the sealing function with the contaminant protection function. No separate filter component is needed, as the gap between existing components performs the filtration and protection role.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3798439B1Fuel supply device
Publication Date: 2025.04.09 ANDREAS STIHL AG & CO KG
  • EP3798439B1 patent drawingFigure 1
  • EP3798439B1 patent drawingFigure 2~3
  • EP3798439B1 patent drawingFigure 4~7

AI summary

A fuel supply device (1) has a housing (2) in which an intake channel section (3) is formed. At least one fuel opening (11, 12) opens into the intake channel section (3). The fuel supply device (1) has at least one fuel channel (26, 27, 28) in which a valve (23, 24, 25) is arranged. The valve (23, 24, 25) has a valve plate (29, 30, 31). The valve (23, 24, 25) has a closed position (41), in which the valve plate (29, 30, 31) rests against a valve seat (32, 33, 34), and an open position (42). The valve plate (29, 30, 31) travels one valve stroke (h) between the open position (42) and the closed position (41).In the fuel channel (26, 27, 28) an annular gap (28, 39, 40, 49) is formed, wherein the gap width (b) of the annular gap (38, 39, 40, 49) is matched to the stroke (a) of the valve plate (29, 30, 31) of the valve (23, 24, 25) such that the gap width (b) is not greater than twice the stroke (a) and wherein the flow cross-section of the annular gap (40) is larger than the flow cross-section of the valve (23, 24, 25).