Fuel Injector Coupling Device Using Snap Ring and Plate Elements
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Solution Overview
Problem
Existing coupling devices for fuel injectors to fuel rails in internal combustion engines face challenges in achieving a reliable and precise connection without resting on the cylinder head, leading to potential pressure fluctuations and noise transmission.
Innovation Solution
A coupling device comprising a fuel injector cup with a first and second plate element, a recess, and a snap ring, which forms a positive or torque-proof coupling to securely retain the fuel injector in the cup, allowing assembly without additional metallic contact, using a single screw element for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional coupling device is used to connect the fuel injector to the fuel rail, then the connection can be established, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The coupling device is divided into two separate plate elements: a first plate element integrated with the fuel injector cup and a second plate element integrated with the fuel injector. This segmentation allows each plate to be independently manufactured and then coupled together, simplifying the overall device complexity while maintaining connection reliability through the distributed coupling structure.
Solution Approach 2:
The second plate element is positioned within a recess of the first plate element, creating a nested arrangement. The snap ring is inserted into a groove to secure the second plate element within the recess. This nested structure achieves reliable mechanical coupling while minimizing the overall space required and reducing device complexity.
2Stability of the object's composition
If additional metallic contact is used to secure the fuel injector, then the connection stability improves, but noise transmission increases
Solution Approach 1:
The coupling device uses plate elements with distributed contact surfaces rather than concentrated metallic contact points. The snap ring acts as an intermediary element that secures the connection through elastic deformation in the groove, providing stable mechanical coupling while reducing direct rigid metallic contact that would transmit noise.
Solution Approach 2:
The design changes the contact parameters by distributing the connection force across multiple plate elements and using elastic deformation of the snap ring rather than rigid metallic contact. This parameter change maintains connection stability while reducing noise transmission by avoiding direct rigid metal-to-metal contact paths.
3Ease of manufacture
If a simple coupling structure is used, then the manufacturing becomes easier, but the precision of fuel injection positioning deteriorates
Solution Approach 1:
The first plate element is pre-integrated with the fuel injector cup and the second plate element is pre-integrated with the fuel injector during manufacturing. This preliminary integration ensures precise positioning relationships are established beforehand, allowing the final assembly to be simple while maintaining injection angle precision through the pre-established geometric relationships.
Solution Approach 2:
The design replaces complex adjustable mechanical positioning systems with a fixed geometric coupling structure. The plate elements and snap ring create a predetermined positioning geometry that ensures precise fuel injection positioning without requiring complex adjustment mechanisms, thereby simplifying manufacturing while maintaining precision.
4Device complexity
If the fuel injector is retained without a positive fitting coupling, then the device complexity decreases, but the fuel injector may move during operation
Solution Approach 1:
The snap ring is inserted into an asymmetric groove structure that prevents removal while allowing installation. The groove geometry is designed so that the snap ring can be inserted in one direction but is locked in position, creating a non-reversible connection that ensures positioning reliability without requiring complex fastening mechanisms.
Solution Approach 2:
The snap ring utilizes elastic deformation and curved geometry to achieve a secure connection. The circular cross-section of the snap ring allows it to flex during installation and then elastic recovery to lock firmly in the groove, providing reliable positioning with a simple continuous structure rather than multiple discrete components.
Data Source
AI summary
Coupling device for hydraulically and mechanically coupling a fuel injector to a fuel rail of a combustion engine. The fuel injector has a central longitudinal axis. The coupling device has a fuel injector cup being designed to be hydraulically coupled to the fuel rail and to engage a fuel inlet portion of the fuel injector, a first plate element being fixedly coupled to the fuel injector cup, the first plate element comprising a recess, and a second plate element being fixedly coupled to the fuel injector and being arranged in the recess and being fixedly coupled to the first plate element to retain the fuel injector in the fuel injector cup in direction of the central longitudinal axis. The fuel injector comprises a groove. A snap ring is arranged in the groove of the fuel injector and is designed to fixedly couple the second plate element to the fuel injector.