Fuel Injector Coupling Device for Precise Injection Angle Control
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Solution Overview
Problem
Existing coupling devices for hydraulically and mechanically connecting fuel injectors to fuel rails in internal combustion engines face challenges in maintaining precise and reliable connections while preventing movement and rotation, which can lead to pressure fluctuations and incorrect injection angles.
Innovation Solution
A coupling device featuring a fuel injector cup with a central longitudinal axis, a first retaining element, a second retaining element, and an interface element that form-fit couples to prevent movement and rotation, ensuring a secure and precise connection between the fuel injector and the fuel rail, including an electrical connector for simplified assembly and reduced part count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional coupling device is used to connect fuel injectors to fuel rails, then the connection can be established, but movement and rotation of the fuel injector may occur leading to pressure fluctuations and incorrect injection angles
Solution Approach 1:
The coupling device is divided into distinct functional segments: a first retaining element for hydraulic coupling to the fuel rail, a second retaining element for mechanical engagement with the fuel injector, and an interface element with tab and recess features. This segmentation allows each component to perform its specific function optimally while working together to prevent both axial movement and rotational displacement, thereby maintaining injection precision and connection reliability.
2Reliability
If multiple separate components are used to retain the fuel injector and prevent rotation, then the connection stability improves, but the device complexity and manufacturing cost increase
Solution Approach 1:
The first retaining element, second retaining element, and interface element are combined into a single integrated coupling device. This merging maintains all necessary functions: hydraulic coupling to the fuel rail, mechanical retention of the fuel injector, and prevention of rotational movement through the tab-recess interface. By consolidating these functions into one component, the device complexity is reduced while connection stability is preserved.
Solution Approach 2:
The coupling device serves multiple functions simultaneously: it provides hydraulic coupling to the fuel rail through the first retaining element, mechanical retention of the fuel injector through the second retaining element, and rotational prevention through the interface element with tab and recess. This multi-functionality eliminates the need for separate components for each function, simplifying the overall assembly while maintaining connection stability.
3Manufacturing precision
If a precise connection system is implemented to prevent movement and rotation, then injection angle accuracy improves, but the assembly process becomes more complex
Solution Approach 1:
The interface element incorporates an asymmetric tab-recess configuration where the tab extends in a specific direction and engages with a corresponding recess. This asymmetric design provides inherent rotational guidance and prevents misalignment during assembly. The geometry itself enforces the correct orientation, eliminating the need for complex alignment procedures while ensuring precise injection angles.
Solution Approach 2:
The coupling device is pre-configured with the tab and recess features in the correct relative positions during manufacturing. This preliminary arrangement of the retaining elements and interface features ensures that when the assembly is performed, the precise geometric relationships are already established, simplifying the assembly process while guaranteeing the required injection angle accuracy without requiring complex alignment steps.
Data Source
AI summary
A coupling device for hydraulically and mechanically coupling an injection valve to a fuel rail of a combustion engine has a fuel injector cup with a central longitudinal axis, is hydraulically coupled to the fuel rail and in engagement with the injection valve. A first retaining element is fixedly coupled to the fuel injector cup, a second retaining element is fixedly coupled to the injection valve, the second retaining element being coupled to the first retaining element to prevent a movement of the second retaining element relative to the first retaining element in a first direction of the central longitudinal axis to retain the injection valve in the fuel injector cup, and an interface element which is operable to axially couple the injection valve with the second retaining element in a fixed way. Fuel injection arrangement with a coupling device and an injection valve which is coupled to the coupling device.