Spherical Nozzle Assembly for Fuel Injector Leakage Control
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Solution Overview
Problem
Existing fuel injection systems in dual-fuel engines face issues with liquid fuel leakage into the main fuel system, leading to excessive energy input, reduced engine reliability, and safety hazards, particularly during deceleration phases and when operating on liquid fuel alone, due to insufficient sealing and wear of radial sealing elements.
Innovation Solution
A nozzle assembly with a spherical or partially spherical closing element, fluid-tightly connected to a sleeve-shaped sealing element, eliminates the need for a guide and enhances sealing performance by compensating for manufacturing and assembly tolerances, using a corrugated or bellows-like sleeve made of metallic material to ensure reliable media separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radial sealing elements such as O-rings or piston rings are used to prevent liquid fuel leakage, then sealing performance is improved, but wear and functional reliability deteriorate over service life
Solution Approach 1:
The patent employs a spherical closing element instead of conventional radial sealing elements. The spherical geometry allows the closing element to maintain continuous contact with the sealing seat while accommodating wear and manufacturing tolerances, eliminating the wear problems associated with O-rings and piston rings. The curved surface ensures uniform pressure distribution and reliable sealing throughout the service life of the fuel injector.
2Reliability
If guide clearance is minimized and guide length is maximized to prevent liquid fuel leakage, then sealing performance is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent eliminates the guide structure entirely by using a spherical closing element that seals directly against a sealing seat. This removes the need for guide clearance optimization and complex guide mechanisms, simplifying the overall device structure while maintaining reliable media separation between the control medium and fuel supply path.
3Reliability
If the spherical closing element is used to compensate for manufacturing tolerances, then sealing performance is improved, but manufacturing precision requirements for other components increase
Solution Approach 1:
The spherical closing element changes the geometric parameters of the sealing interface. Instead of requiring precise linear guide clearance and guide alignment, the spherical geometry provides tolerance compensation through its curved surface contact with the sealing seat. This shifts the manufacturing precision requirements from the guide structure to the sealing seat surface, which can be more easily manufactured with appropriate tolerances.
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 effectively prevents leakage, reduces wear, and maintains consistent sealing performance throughout the fuel injector's life, ensuring reliable operation and compliance with certification standards by preventing gas entry into the liquid fuel system and maintaining uniform pressure distribution.
Implementation Method 1
The closing element is spherical or at least partially spherical in the region of a sealing surface interacting with the sealing seat and is directly or indirectly fluid-tight connected to the sleeve-shaped sealing element
Implementation Method 2
a corrugated or bellows-like sleeve made of metallic material to ensure reliable media separation
Implementation Method 3
The closing element is subjected on one side to combustion chamber pressure and on the other side to a control pressure prevailing in a control chamber
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a nozzle assembly (1) for a fuel injection valve for injecting a gaseous and/or liquid fuel into a combustion chamber (2) of an internal combustion engine, comprising a closing element (4), which interacts with a sealing seat (3) and can be moved back and forth, for opening and closing at least one injection opening (5), combustion chamber pressure being applied to one side of the closing element and a control pressure present in a control chamber (6) being applied to the other side of the closing element, which control chamber is separated from a supply path (7) for the fuel by a sleeve-shaped sealing element (8). According to the invention, the closing element (4) is spherical, or is partially spherical at least in the region of a sealing surface (9) which interacts with the sealing seat (3), and the closing element is directly or indirectly connected in a fluid-tight manner to the sleeve-shaped sealing element (8). The invention also relates to a fuel injection valve having a nozzle assembly (1) of this type.