Fuel Rail Coupling Device With Retaining Element
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Solution Overview
Problem
Existing coupling devices for mechanically coupling a fuel rail to a cylinder head of a combustion engine often fail to provide a reliable and precise connection while minimizing pressure pulsation and vibration transmission, and they are difficult to manufacture and assemble efficiently.
Innovation Solution
A coupling device featuring a holding fixture with a through hole, a fastening element with a head and shank portion, and a retaining element with a cross-section restriction, which includes a plastic retaining element for secure engagement and a rubber spring element to reduce noise and vibration, allowing for pre-assembled and secure attachment of the fuel rail to the cylinder head without direct contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional coupling device is used to mechanically couple the fuel rail to the cylinder head, then the connection is established, but the coupling is not secure and may be accidentally disassembled due to collision with environmental components
Solution Approach 1:
The fastening element is nested within the holding fixture during transportation and assembly. The retaining element is inserted through the through-hole of the holding fixture and engages with the fastening element, creating a nested configuration that prevents accidental disassembly while maintaining structural simplicity
Solution Approach 2:
The fastening element is pre-positioned in a captive and aligned manner within the holding fixture before assembly. The retaining element is pre-configured with engagement features that automatically secure the fastening element during the assembly process, eliminating the need for separate securing operations
2Reliability
If the fastening element is loosely positioned during transportation, then assembly is simple, but the fastening element may be disassembled due to accidental collision with environmental components
Solution Approach 1:
The fastening element is pre-positioned in a captive and aligned manner within the holding fixture before assembly. The retaining element is pre-configured with engagement features that automatically secure the fastening element during the assembly process, eliminating the need for separate securing operations
Solution Approach 2:
The retaining element automatically secures the fastening element through its engagement features (such as ribs engaging with grooves or threaded engagement) without requiring additional securing operations. The design self-secures the fastening element during assembly, preventing accidental disassembly while maintaining assembly simplicity
3Reliability
If a retaining component with only fractional engagement with the shank portion is used, then the device complexity is reduced, but the fixing of the fastening element is insufficient and friction depends on material and tolerances
Solution Approach 1:
The retaining element features localized engagement structures (such as ribs with grooves or threaded sections) at specific positions along its length. These local engagement features concentrate the securing function at critical points, providing reliable fixing without requiring complex structures along the entire length of the retaining element
Solution Approach 2:
The retaining element may be made from plastic material that provides both structural integrity and sufficient friction engagement with the metallic fastening element. This composite material approach allows for reliable fixing through a combination of mechanical engagement and material friction properties
4Object-affected harmful factors
If the coupling device allows direct contact between the fuel rail and cylinder head, then the assembly is simpler, but pressure pulsation and vibration transmission are increased
Solution Approach 1:
The holding fixture acts as an intermediary component between the fuel rail and cylinder head, providing mechanical coupling while isolating vibrations and pressure pulsations. The fixture's structure and material properties are designed to attenuate high-frequency vibrations, preventing their transmission to the cylinder head while maintaining the mechanical connection
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
The solution enables a fast, secure, and reliable coupling of the fuel rail to the cylinder head, reducing the risk of accidental disassembly and noise transmission, while facilitating efficient assembly and manufacturing with improved dynamic behavior and reduced vibration.
Implementation Method 1
a rubber spring element to reduce noise and vibration
Implementation Method 2
the friction between the retaining element and the shank portion may depend on the material of these both components and tolerances of the inner diameter of the retaining element and the outer diameter of the shank portion
Data Source
AI summary
The coupling device comprises a holding fixture being designed to be mechanically coupled to the fuel rail and comprising a through hole extending between a first surface and a second surface, the second surface opposing the first surface and being arranged and designed to face the cylinder head. Furthermore the coupling device comprises a fastening element being designed to be fixedly coupled to the cylinder head. The fastening element comprises a head portion and a shank portion. The head portion faces the first surface of the holding fixture and the shank portion is being partially arranged in the through hole and is designed to be in engagement with the cylinder head. In addition the coupling device comprises a retaining element being arranged inside the through hole, being coupled with the holding fixture, comprising in a given latch area a cross-section restriction and being in engagement with the shank portion at least in this latch area. The retaining element is formed as a one-piece unit.