Fuel Injection Device Reducing Dribbling via Seat Gap Control
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Solution Overview
Problem
Existing fuel injection devices struggle to reduce soot component discharge by minimizing fuel dribbling at the end of injection, particularly during valve closure, as they do not effectively manage fuel inflow after injection.
Innovation Solution
A fuel injection device design featuring a valve body and a seat member with a fuel injection hole, where the gap between the seat member and the valve body downstream of the injection hole is smaller than the hole's diameter, ensuring efficient fuel discharge and minimizing dribbling during valve closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the gap between the seat member and valve body downstream of the fuel injection hole is made smaller than the hole diameter, then fuel dribbling is reduced and soot generation is minimized, but the manufacturing precision requirements increase
Solution Approach 1:
The invention changes the critical parameter from gap size alone to the ratio relationship between gap size and hole diameter. By specifying that the gap be smaller than the hole diameter (rather than a fixed absolute value), the design accommodates manufacturing variations while maintaining the functional effect of reducing fuel dribbling and soot generation.
Solution Approach 2:
The invention combines two geometric parameters (gap width and hole diameter) into a composite design criterion. Rather than controlling just the gap dimension, the solution uses the relationship between gap and hole diameter as a unified design parameter, which inherently accounts for both atomization performance and dribbling prevention.
2Object-generated harmful factors
If the gap between the seat member and valve body is reduced to minimize fuel inflow after injection, then soot components are reduced, but the atomization performance may be compromised
Solution Approach 1:
The invention transforms the design approach by changing from absolute gap dimension control to a relative parameter relationship (gap smaller than hole diameter). This parameter transformation allows the system to simultaneously achieve good atomization (adequate gap for fuel flow) and reduced soot (sufficiently small gap to prevent dribbling).
Solution Approach 2:
The invention applies different functional requirements to different regions of the flow path. The gap region is designed to control fuel inflow and prevent dribbling, while the injection hole region maintains dimensions optimized for atomization. This local differentiation of functional requirements allows both objectives to be achieved simultaneously.
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
This configuration reduces fuel dribbling and adhesion, which are soot generation factors, by maintaining high-speed fuel flow and reducing pressure loss, thereby minimizing soot formation.
Implementation Method 1
The seat member is formed such that a gap between the seat member and the opposing valve body in the whole region on the downstream side of the fuel injection hole is smaller than a diameter of the fuel injection hole
Data Source
AI summary
Provided is a structure capable of reducing dribbling of fuel generated when a valve body is closed. In order to achieve the above object, a fuel injection device includes: a valve body; and a seat member having a seat portion on which the valve body is seated and having a fuel injection hole formed on a downstream side of the seat portion. The seat member is formed such that a gap between the seat member and the opposing valve body in the whole region on the downstream side of the fuel injection hole is smaller than a diameter of the fuel injection hole.