Variable EDM Spray-Hole Geometry for Fuel Injector Nozzles
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Solution Overview
Problem
Current Electrical Discharge Machining (EDM) methods are limited in producing fuel injector nozzles with venturi and converge-diverge spray-hole designs, which are necessary for improved fuel injection and atomization, due to high capital costs and limited ability to create accurate and repeatable venturi injection orifices.
Innovation Solution
A method utilizing Electrical Discharge Machining (EDM) that involves a controller to adjust operational parameters and electrode positions to create specific orifice sections with varying flow areas, forming a venturi or converge-diverge spray-hole design by applying different voltages and advancing the electrode in controlled increments, allowing for the production of fuel injector nozzles with increased precision and longevity of EDM machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional EDM methods are used to create spray-holes, then the process is simple and equipment cost is low, but the ability to create accurate venturi and converge-diverge designs is limited
Solution Approach 1:
The patent applies dynamics by making the EDM process parameters variable rather than fixed. The controller dynamically adjusts voltage, current, pulse duration, and electrode positioning during the machining process to create different orifice sections with varying flow areas, enabling venturi and converge-diverge geometries that require continuous parameter changes throughout the drilling operation.
Solution Approach 2:
The patent implements parameter changes by systematically varying multiple EDM operational parameters including voltage level, current intensity, pulse frequency, and electrode advancement rate. These parameter changes allow the same EDM machine to produce different orifice sections (first, second, third sections with different flow areas) within a single spray-hole, achieving complex venturi geometries without requiring multiple machines or processes.
2Manufacturing precision
If laser drilling technology is used to produce venturi injection orifices, then accurate venturi designs can be achieved, but capital costs are high
Solution Approach 1:
The patent applies universality by enabling a standard EDM machine to perform multiple functions: it can create straight-walled orifices, venturi-shaped orifices, and converge-diverge spray-holes using the same equipment. The controller system allows one machine to replace what would traditionally require specialized laser drilling equipment, making the EDM machine versatile enough to handle various orifice geometries without additional capital investment.
Solution Approach 2:
The patent substitutes the mechanical/laser-based drilling system with an electrical discharge machining system. Instead of using laser energy or mechanical drilling to create venturi geometries, the patent uses controlled electrical discharges (sparks) to erode material and form the desired shapes, replacing expensive laser technology with a more cost-effective EDM approach enhanced by intelligent parameter control.
3Reliability
If conventional EDM creates straight-walled orifices, then the process is reliable and repeatable, but fuel injection and atomization performance is limited
Solution Approach 1:
The patent applies local quality by creating different geometric characteristics in different sections of the same orifice. The first orifice section has one flow area characteristics, the second section has different characteristics, and the third section has yet another set of characteristics. Each section is machined with specific parameter settings optimized for its local geometric requirements, allowing the overall orifice to achieve superior fuel injection and atomization performance while maintaining process reliability through controlled parameter variations.
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 method enables the accurate and reliable generation of venturi and converge-diverge spray-hole designs in fuel injector nozzles, enhancing fuel injection and atomization processes while reducing the high capital costs associated with laser drilling technology and extending the life of EDM machines.
Implementation Method 1
Electrical Discharge Machining ("EDM") is a process by which conductive particles are removed from the surface of a positively charged workpiece by a series of discharges emanating from a negatively charged electrode. The electrical discharges or sparks create micro-craters on the workpiece by removing material along the cutting path through melting and vaporization.
Data Source
AI summary
A method is provided comprising identifying an alignment point of a workpiece; positioning a first end of an electrode in the direction of the alignment point of the workpiece; applying a first voltage to the electrode wherein the applied first voltage generates a spark; rotating the electrode in a first direction; advancing the electrode toward the alignment point by a first distance wherein advancing the electrode and applying the first voltage creates a first orifice section; applying a second voltage to the electrode and modifying one or more operational parameters of the electrode; advancing the electrode toward the alignment point by a second distance wherein advancing the electrode and applying the second voltage causes formation of at least a second orifice section; wherein the first and second orifice sections cooperate to form an orifice comprising a first flow area and a second flow area.