External Needle Guide Injection Nozzle for High-Flow Fuel Delivery
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Solution Overview
Problem
Existing injection nozzles for liquid and gaseous fuels face issues with asymmetrical sliding of the nozzle needle during closure, leading to wear and impaired guiding properties due to widening guide gaps under high pressure, and require a compromise between fluid flow and guidance that often results in throttling points.
Innovation Solution
The injection nozzle design relocates the guide element from the inside to the outside of the nozzle body, ensuring optimal guidance of the nozzle needle near the sealing seat, separating the flow path and guide, and allowing for a larger fluid cross-section without internal guides, thus preventing asymmetrical sliding and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal guides are provided in the nozzle body to guide the nozzle needle, then the nozzle needle can be guided, but the guide gaps widen under high injection pressure which impairs guiding properties and causes asymmetrical sliding
Solution Approach 1:
The guide element is extracted from the internal structure of the nozzle body and repositioned to the external surface. This allows the guide to be positioned close to the sealing seat without creating internal flow restrictions. The guide element is rigidly connected to the nozzle needle and guided over an external guide surface formed on the nozzle body, eliminating the problem of guide gap widening under pressure.
2Reliability
If internal guides are provided near the sealing seat to center the nozzle needle, then guidance is improved, but the cross-sectional area for fluid flow is reduced creating throttling points
Solution Approach 1:
The guide element is moved from the internal flow path to the external surface of the nozzle body. This extraction eliminates the conflict between guidance and fluid flow, as the guide no longer occupies space within the fluid passage. The external guide surface is formed on the nozzle body and the guide element is guided over it, allowing full fluid cross-section while maintaining precise guidance near the sealing seat.
3Measurement precision
If multiple internal guides are provided to ensure precise guidance, then the nozzle needle guidance is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The guide structure is extracted from the complex internal multi-guide arrangement and simplified to a single external guide element. This external guide element is rigidly connected to the nozzle needle and guided over an external guide surface, providing precise guidance with a simpler structure that is easier to manufacture and assemble.
4Reliability
If the guide is positioned close to the sealing seat to prevent asymmetrical sliding, then wear is reduced, but internal guides in this position are difficult to manufacture
Solution Approach 1:
The guide element is extracted from the difficult-to-manufacture internal position and repositioned to the external surface of the nozzle body. This external positioning allows for easier manufacturing of both the guide element and the guide surface, while maintaining close proximity to the sealing seat to prevent asymmetrical sliding and reduce wear.
Data Source
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AI summary
The invention relates to an injection nozzle (1) for injecting a fluid, in particular a liquid or gaseous fuel, comprising: - a nozzle body (2) which is designed to be hollow-cylindrical at least in portions and forms a sealing seat (3) via which a flow path (4) for the fluid to be injected leads, - a nozzle needle (5) which is accommodated in the nozzle body (2) for reciprocating movement and has a sealing surface (6) that interacts with the sealing seat (3), - a guide element (7) which is fixedly connected to the nozzle needle (5) and is guided by means of an external guide (8) of the nozzle body (2). The invention further relates to a fuel injector having an injection nozzle (1) according to the invention.