Fuel Rail Inlet Fitting With Self-Retaining Pin and Pulse Damping
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Solution Overview
Problem
Conventional fuel delivery systems face challenges in manufacturing complexity and cost due to precise requirements for high-pressure fuel line-to-fuel rail connections, and they struggle with managing pressure pulsations and providing reliable, simple connections between fuel injectors and injector cups.
Innovation Solution
The fuel delivery system employs an inlet fitting with a self-retaining elastic retaining pin to decouple retention and sealing functions, and uses a similar pin to secure fuel injectors to injector cups, providing a fluid-tight connection with fewer parts and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional fuel line connections are used with integrated retention and sealing features, then the connection can be achieved in a single component, but the manufacturing complexity and cost increase due to high precision requirements
Solution Approach 1:
The connection assembly is divided into separate functional components: the fuel line connector provides retention through external threads engaging with the fuel rail inlet, while the O-ring seal provides sealing independently. This segmentation allows each component to be manufactured with standard tolerances rather than requiring high precision integration of retention and sealing features into a single component.
2Reliability
If conventional fuel line connections are used, then the connection can be made, but the retention features and sealing features are coupled using highly variable processes that are difficult to control
Solution Approach 1:
By separating the retention function (external threads on fuel line connector) from the sealing function (O-ring seal), the design eliminates the need for highly variable coupled processes. Each component can be manufactured and assembled independently using standardized, easily controlled processes, improving both reliability and manufacturability.
3Reliability
If conventional connections are used, then the fuel delivery system can operate, but pressure pulsations caused by injector delivery timing are not reduced
Solution Approach 1:
The inlet fitting acts as an intermediary component between the fuel line and fuel rail inlet. It includes a damping chamber that receives fuel from the fuel line and distributes it to the fuel rail, absorbing pressure pulsations generated by injector delivery timing. This intermediary structure isolates the pressure variations from the main fuel delivery system.
4Reliability
If conventional fuel injector connections are used, then the injector can be secured to the injector cup, but the connection requires multiple parts and complex manufacturing
Solution Approach 1:
The injector connection uses separate retainers that independently secure the injector to the injector cup, while sealing is provided by dedicated sealing elements. This segmentation allows each component to perform its specific function with simple geometry, reducing manufacturing complexity while maintaining connection reliability through the combined action of multiple simplified parts.
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 solution simplifies the connection process, reduces manufacturing costs, and effectively manages pressure pulsations, ensuring reliable and efficient high-pressure fuel delivery to engine cylinders.
Implementation Method 1
The retaining pin is elastically expandable and contractible in a direction perpendicular to the pin longitudinal axis
Implementation Method 2
The inlet fitting has a generally cylindrical leading end that is disposed in, and sealed with respect to, the main fuel channel of the fuel rail via a first O-ring seal
Implementation Method 3
the retaining pin damps vibration of the assembly
Data Source
AI summary
A connection assembly is used to connect a first body to a second body. The first body includes a bore that is coaxial with a first axis, and a retainer opening that extends coaxially with a second axis. The second axis is perpendicular to the first axis and offset relative to the first axis. In addition, a portion of the retainer opening intersects the bore. The second body includes an insertion portion that is disposed in the bore, a fluid passage that extends through the insertion portion and communicates with the bore, and an outer surface of the second body has a channel. The connection assembly employs an elastic retaining pin that retains the insertion portion within the bore. The retaining pin is disposed in the retainer opening such that a portion of the retaining pin resides in the channel, and the retaining pin is self-aligning and self-retaining.