Fuel Injection Device Nested Projections Prevent Leakage
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Solution Overview
Problem
Existing fuel injection devices face issues with fuel leakage due to radial deformation and stress concentration at connecting portions when injecting high-pressure fuel, leading to potential fracturing and gap formation between tubular members.
Innovation Solution
The fuel injection device incorporates inside and outside projections formed from tubular members made of magnetic and non-magnetic materials, where the outside projections are placed radially outer to the inside projections, limiting radial deformation and stress concentration at connecting portions, thereby preventing fuel leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure fuel is injected through the fuel passage, then fuel injection performance is improved, but radial deformation and stress concentration occur at the connecting portions of the tubular members
Solution Approach 1:
The patent applies nesting by placing the inside projection inside the outside projection, forming a nested structure. The inside projection is positioned within the outer circumference of the outside projection, creating a concentric arrangement that reinforces the connecting portions against radial deformation while maintaining fuel injection performance
Solution Approach 2:
The patent uses composite construction by combining magnetic material (first and third tubular members) with non-magnetic material (second tubular member). This composite structure allows optimization of different regions for specific functions while maintaining overall structural integrity under high pressure conditions
2Ease of manufacture
If the tubular members are joined by welding to form the housing, then assembly is simplified, but stress concentration causes fracturing of the welded portions
Solution Approach 1:
The patent applies preliminary action by pre-forming the inside and outside projections on the tubular members before final assembly. These projections are created in advance to reinforce the connecting portions, preventing stress concentration and welding fracturing before the high-pressure fuel injection operation begins
3Stress or pressure
If the connecting portions deform radially under pressure, then fuel injection pressure is maintained, but gaps form between tubular members causing fuel leakage
Solution Approach 1:
The nested arrangement of inside projection within outside projection creates a reinforced structure that resists radial deformation. This nested configuration allows the connecting portions to maintain their shape under high fuel pressure, preventing gap formation and fuel leakage between tubular members
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 effectively prevents fuel leakage while maintaining the ability to inject high-pressure fuel by limiting radial deformation and stress concentration at the connecting portions, ensuring the integrity of the fuel injection process.
Implementation Method 1
A coil is placed on a radially outer side of the intermediate tubular member and a stationary core. With this construction, when the coil is energized, a movable core can be magnetically attracted to the stationary core.
Implementation Method 2
two tubular members, which are located at two ends, respectively, of the housing, are made of a magnetic material
Data Source
AI summary
An inside projection is formed in one piece with a second tubular member and projects in a tubular form toward a third tubular member, and an outside projection is formed in one piece with the third tubular member and projects in a tubular form toward the second tubular member, while an inner wall of the outside projection is engaged with an outer wall of the inside projection. Another inside projection is formed in one piece with the second tubular member and projects in a tubular form toward a first tubular member, and another outside projection is formed in one piece with the first tubular member and projects in a tubular form toward the second tubular member, while an inner wall of the outside projection is engaged with an outer wall of the inside projection.