Gas Fuel Injector Valve Seat Geometry to Prevent Leakage
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Solution Overview
Problem
Conventional gas fuel injectors face issues with fuel leakage due to gaps formed between the valve seat and body, especially when the valve body tilts or the cylinder pressure becomes excessively high.
Innovation Solution
A normally-closed gas fuel injector with a valve seat member and valve body having specific geometric shapes, such as tapered or spherical sealing surfaces, ensures alignment and close contact even when the valve body tilts, using an outwardly-opening check valve structure to prevent fuel leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat valve seat and valve body structure is used, then the manufacturing is simple, but gaps form between the valve seat and body when the valve tilts, causing fuel leakage
Solution Approach 1:
The valve body is designed with a spherical sealing surface that contacts the annular valve seat. This spherical geometry allows the valve body to self-align and correct tilting movements, ensuring continuous sealing contact even when the valve shaft oscillates. The curved surface replaces the conventional flat sealing interface, eliminating gaps while maintaining manufacturing feasibility.
2Reliability
If a normally-closed valve structure is used, then fuel injection control is achieved, but fuel leakage occurs when cylinder pressure becomes excessively high
Solution Approach 1:
The spherical sealing surface on the valve body combined with the annular valve seat creates a self-correcting sealing mechanism. When high cylinder pressure occurs, the spherical geometry ensures the valve body maintains optimal contact with the valve seat, preventing pressure-induced leakage that would occur with flat sealing surfaces.
Solution Approach 2:
The spherical valve body automatically self-aligns with the annular valve seat through its geometric properties, correcting any tilting or oscillation without external intervention. This self-service alignment mechanism ensures continuous sealing under varying pressure conditions.
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
Enhances alignability and sealing properties to effectively prevent fuel leakage, even under high in-cylinder pressures, by ensuring smooth alignment and close contact between the valve seat and body surfaces.
Implementation Method 1
a solenoid that is disposed in the main body and is configured to drive the opening/closing valve to open during energization
Implementation Method 2
the sealing surface of the valve body is formed in a tapered shape, an arch shape, or a spherical shape with the center axis of the valve shaft as the center line
Data Source
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AI summary
An object of the present invention is to provide a gas fuel injector including a normally-closed opening/closing valve, in which it is possible to prevent fuel leakage while the valve is closed even in a case where a pressure in a cylinder into which fuel is injected becomes excessively high or a valve body tilts. An opening/closing valve (20A) includes a valve shaft (19), a valve body (21A), and a valve seat member (22). The valve seat member (22) includes: a valve hole (24); and a seat surface (23) having an annular shape that is formed at a distal end portion of a peripheral wall protruding along an outer periphery of the valve hole (24). The valve body (21A) includes a sealing surface (211A) having a tapered shape, an arch shape, or a spherical shape to be in contact with the seat surface (23) when the opening/closing valve (20A) is closed.