Fuel Distributor Screw Connection Sealing and Contamination Control
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Solution Overview
Problem
Existing fuel distributor systems for medium-pressure fuel injection systems in spark-ignited internal combustion engines face challenges in creating cost-effective connections suitable for medium pressure while preventing contamination and ensuring structural integrity, particularly with plastic components which cannot be brazed like steel.
Innovation Solution
A plastic fuel distributor rail design featuring a screw element with an external thread and annular groove, where the sealing ring leads the external thread during screwing, and conical thread shapes with steeper angles, combined with longitudinal and transverse ribs for enhanced stability, allows for self-tapping connections that seal and prevent contamination, reducing material costs and installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steel fuel rail uses brazing for high-pressure connections, then connection strength and reliability are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces the brazing process (thermal/chemical joining) with a mechanical screw connection system. The screw element with external thread engages with an internally threaded recess in the housing part, creating a mechanically secure connection that eliminates the need for brazing operations, specialized equipment, and complex manufacturing processes while maintaining connection reliability under medium pressure conditions
Solution Approach 2:
The screw element is designed as a self-tapping fastener that creates its own threaded engagement with the housing part during installation. The self-tapping feature allows the screw to automatically form matching threads in the recess without requiring pre-threaded holes or separate tapping operations, significantly simplifying the manufacturing process and enabling direct assembly
2Ease of manufacture
If a plastic fuel distributor rail is used to reduce cost, then manufacturing cost decreases, but connection strength and pressure resistance worsen
Solution Approach 1:
The patent employs a composite construction where a plastic housing part is combined with a metal screw element. The plastic component provides cost-effective, corrosion-resistant fuel distribution channels, while the metal screw element contributes high strength, pressure resistance, and secure fastening capability. This composite approach allows the assembly to achieve the mechanical strength of metal connections while maintaining the cost and corrosion advantages of plastic components
Solution Approach 2:
The patent applies different material properties to different functional regions: the housing part is made of plastic for fuel distribution and cost efficiency, while the screw element is made of metal for strength and pressure resistance. This localized material selection optimizes the overall performance by giving each component the material properties best suited for its specific function
3Object-affected harmful factors
If the annular groove is positioned to lead the external thread, then contamination prevention is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into the annular groove feature: it serves as both the seating position for the sealing ring (providing sealing functionality) and as a geometric feature that leads the external thread during assembly (providing alignment and contamination prevention). This merging of sealing and thread-leading functions into a single geometric feature avoids adding separate alignment pins, guides, or complex positioning mechanisms, thereby preventing contamination without significantly increasing device complexity
4Strength
If conical thread shapes with steeper angles are used, then structural strength is improved, but manufacturing precision requirements increase
Solution Approach 1:
The self-tapping screw element automatically creates its own threaded engagement with the housing part during installation. The conical thread shape with steeper angle is formed directly by the screwing action itself, eliminating the need for pre-threaded holes or separate tapping operations. This self-service approach allows complex thread geometries to be achieved without requiring highly precise pre-prepared receptacles, as the thread form is created in-situ by the screw element
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 enables a cost-effective, medium-pressure connection with improved structural strength and contamination prevention, ensuring reliable operation by trapping contaminants and maintaining system functionality.
Implementation Method 1
a sealing ring (14), which forms a seal between the screw element (6) and the housing part (2)
Implementation Method 2
the screw element (6) having an external thread (7), with an annular groove (15) being designed on the screw element (6)
Data Source
Figure 1~2
AI summary
A fuel distributor (1), which serves in particular for fuel injection systems of mixture-compressing, applied-ignition internal combustion engines, comprises at least one housing part (2) enclosing a fuel chamber (3), comprises at least one screw element (6), and comprises at least one sealing ring (14). Here, there is provided on the housing part (2) a recess (4) into which the screw element (6) is screwed in a self-tapping manner. Here, the sealing ring (14) forms a seal between the screw element (6) and the housing part (2). Chips formed during the screwing-in process thus remain reliably separated from the fuel chamber (3). The screw element (6) has an external thread (7), wherein on the screw element (6) there is formed an annular groove (15) which receives the sealing ring (14), and wherein the sealing ring (14) leads the external thread (7) of the screw element (6).