Fuel Injection Valve Atomization via S-Shaped Flow Path
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Solution Overview
Problem
Existing fuel injection valves in internal combustion engines produce large droplets in the outer region of the fluid jet due to the spray hole geometry, leading to incomplete fuel vaporization during cold start cycles, resulting in poor mixture preparation and increased exhaust emissions.
Innovation Solution
The valve design relocates the inflow cavity to the spray hole disk, creating an S-shaped flow path and a transverse vortex system, which promotes fluid atomization by deflecting the flow and distributing it along the spray hole wall, allowing for shorter spray holes and improved atomization through targeted flow deflection and vortex generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the spray hole geometry is designed to produce large droplets in the outer region, then wall film deposition on intake pipe walls is achieved during cold start, but incomplete fuel vaporization occurs and exhaust emissions increase
Solution Approach 1:
The spray hole is divided into multiple sections along its length, with each section having a different contour shape. The first section has a contour that expands the fluid jet, while the second section has a contour that constricts it, creating distinct functional zones within a single spray hole structure
Solution Approach 2:
The spray hole contour is designed with radial expansion in the first section and radial constriction in the second section, utilizing dimensional changes in the cross-sectional area along the flow path to control droplet size distribution and atomization characteristics
2Manufacturing precision
If the spray hole length is reduced to improve atomization, then flow outlet vectors are not bundled in parallel and atomization is enhanced, but the structural stability and strength of the spray hole disk may be compromised
Solution Approach 1:
The spray hole is segmented into multiple functional sections with different contour characteristics, allowing the flow to be manipulated in stages - first expanded then constricted - achieving superior atomization without requiring excessive length that would compromise structural integrity
3Manufacturing precision
If the inflow cavity is formed in the valve seat body, then the spray hole geometry can be controlled, but additional machining costs and complexity are added to the valve seat body
Solution Approach 1:
The inflow cavity is extracted from the valve seat body and relocated to the spray hole disk, separating the atomization function from the sealing function. This allows the valve seat body to focus on providing a precise seal while the spray hole disk handles the complex flow conditioning geometry
Solution Approach 2:
The valve assembly is segmented into distinct functional components: the valve seat body for sealing and the spray hole disk for atomization. This functional segmentation allows each component to be optimized independently and manufactured separately with appropriate precision requirements
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 design achieves improved atomization of the fluid, reducing large droplet formation and enhancing fuel vaporization, leading to better mixture preparation and reduced exhaust emissions during cold start cycles.
Implementation Method 1
In the flow entry region of the spray hole within the depression, a transverse vortex system is generated which has vortex axes parallel to the vertical axis of the spray hole disk. Said transverse vortex system, by means of flow rotation, assists the fanning-out of the fluid jet emerging from the respective spray hole.
Implementation Method 2
As a result of the depressions, which represent the inflow cavity, in the spray hole disk, which depressions firstly extend as far as under the valve opening and secondly are covered in the region of the spray holes by the valve seat body, an S-shaped flow is attained in which the fluid flow emerging from the valve opening is deflected twice.
Data Source
AI summary
A valve for atomizing fluid is specified, in particular an injection or metering valve for fuel injection or exhaust-gas systems of motor vehicles, which valve has a valve seat body (11) with a valve seat (14) which surrounds a valve opening (13), a perforated injection disc (17) which bears against the front side of the valve seat body (12) downstream of the valve opening (13) and has at least one spray hole (18) which is offset radially with respect to the valve opening (13), and an inflow cavity (19) which is present between the valve opening (13) and the at least one spray hole (18). For the inexpensive and reproducible production of a stable, corrosion-resistant perforated injection disc (18) with improved atomization of the ejected fluid, the inflow cavity (19) is formed by at least one depression (20) which is made in that disc face of the perforated injection disc (17) which faces the valve seat body (12), in such a way that part of the depression (20) protrudes into the valve opening (13) and the remaining part of the depression (20) is covered by the valve seat body (12). The at least one spray hole (18) is made in that part of the depression (20) which is covered by the valve seat body (12), close to the depression wall, which faces away from the valve opening (13), into the bottom (201) of the depression (20).