Fuel Injector Needle Valve Conical Seating for Leakage Control
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Solution Overview
Problem
Common rail fuel systems face issues with fuel leakage and engine performance due to nozzle tip failures, as existing leak limiters allow fuel to drain into the combustion chamber and do not effectively restrict deliberate injections, leading to increased complexity, cost, and unreliability.
Innovation Solution
A fuel injector design featuring a nozzle member with conical seating surfaces and a needle valve member that selectively restricts fuel flow through orifices, using existing components to minimize leakage and maintain engine performance during nozzle tip failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a limiter valve is added to limit fuel leakage through the nozzle, then fuel leakage is reduced, but device complexity and system cost increase
Solution Approach 1:
The patent combines the leak limiting function with the existing needle valve assembly by providing a conical leak limiting surface on the needle valve member that engages with a corresponding conical surface on the nozzle member. This merging eliminates the need for a separate limiter valve component, reducing system complexity while maintaining fuel leakage control functionality.
Solution Approach 2:
The needle valve member is designed to perform multiple functions: it serves as both the injection control valve and the leak limiting mechanism. The conical leak limiting surface on the needle valve member engages with the nozzle member's conical surface to restrict fuel flow during nozzle tip failure, making the needle valve assembly a multi-functional component that reduces overall system complexity.
2Object-affected harmful factors
If a limiter valve is added to limit fuel leakage through the nozzle, then fuel leakage is reduced, but manufacturing cost increases
Solution Approach 1:
The leak limiting function is merged into the existing needle valve assembly, eliminating the need for additional limiter valve components. This reduces the total number of parts to be manufactured, assembled, and quality-checked, thereby reducing manufacturing cost while maintaining effective fuel leakage control.
Solution Approach 2:
The needle valve member incorporates the leak limiting functionality directly into its structure through the conical leak limiting surface. This self-service approach allows the existing needle valve assembly to perform both injection control and leak limiting functions without requiring separate dedicated components, reducing overall manufacturing cost.
3Ease of operation
If the needle valve is designed with a large hydraulic surface area at the base end, then deliberate injection control is improved, but fuel leakage during nozzle failure increases
Solution Approach 1:
The patent introduces a conical leak limiting surface on the needle valve member with specific geometric properties (angle and surface area) that are locally optimized for leak limiting functionality. This localized quality change at the leak limiting surface allows the needle valve to effectively restrict fuel flow during nozzle tip failure while maintaining its overall large hydraulic surface area for deliberate injection control.
Solution Approach 2:
The needle valve member is segmented into functionally distinct surfaces: a large hydraulic surface area at the base end for injection control and a separate conical leak limiting surface for fuel leakage restriction. This segmentation allows each surface to be optimized for its specific function, balancing injection control performance with leak limiting capability.
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 fuel injector effectively limits fuel leakage and maintains engine performance by using existing components to restrict fuel flow, reducing complexity and cost while improving fuel efficiency and emissions.
Implementation Method 1
The male conical seating surface is configured to engage the female conical seating surface to restrict fuel flow through the at least one orifice. The needle valve member includes a base end having a hydraulic surface area that is greater than a hydraulic surface area of the tip end.
Data Source
AI summary
A fuel injector for a fuel system is disclosed. The fuel injector has a nozzle member and a needle valve member slidingly disposed with the nozzle member. The nozzle member has a tip portion, at least one orifice disposed at the tip portion, a base portion, and a female conical seating surface disposed at the base portion. The needle valve member has a tip end configured to selectively restrict fuel flow through the at least one orifice, a base end, and a male conical seating surface disposed between the tip end and the base end. The male conical seating surface is configured to engage the female conical seating surface to restrict fuel flow through the at least one orifice and has a hydraulic surface area greater than a hydraulic surface area of the base end of the needle valve member.