Fuel Injection Hole Surface Roughness for Atomization
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Solution Overview
Problem
Existing fuel injection devices have insufficient fuel atomization, which limits fuel economy and efficiency in internal combustion engines.
Innovation Solution
A fuel injection device design featuring an injection hole with a body portion that includes an inlet-channel-forming portion and an outlet-channel-forming portion, where the surface roughness of the outlet-channel-forming portion is greater than that of the inlet-channel-forming portion, and the diameter of the outlet channel is expanded more than the inlet channel, promoting fuel atomization through increased turbulent energy and radial spreading of the fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fuel injection device uses a conventional injection hole design, then the structure is simple, but the fuel atomization is insufficient
Solution Approach 1:
The injection hole structure applies local quality by differentiating the surface roughness between the inlet-channel-forming portion and outlet-channel-forming portion. The inlet channel maintains a smoother surface to preserve fuel flow rate, while the outlet channel features increased surface roughness to disturb fuel flow and enhance atomization. This localized differentiation resolves the contradiction by optimizing each section for its specific function.
Solution Approach 2:
The injection hole is segmented into distinct functional zones: an inlet-channel-forming portion and an outlet-channel-forming portion, each with different surface roughness characteristics. This segmentation allows independent optimization of fuel flow maintenance (inlet) and fuel atomization (outlet), thereby improving overall atomization quality without excessive structural complexity.
2Manufacturing precision
If the outlet channel diameter is expanded more than the inlet channel, then fuel atomization is improved, but the channel structure becomes more complex
Solution Approach 1:
The invention applies parameter changes by varying the diameter expansion ratios of the inlet and outlet channels. The outlet channel has a larger diameter expansion ratio than the inlet channel, which promotes fuel spreading in the radial direction and enhances atomization. This parameter differentiation is integrated into the molded structure, achieving improved atomization without requiring separate assembly components.
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 design enhances fuel atomization, leading to improved fuel economy and efficiency by ensuring the fuel is adequately dispersed upon injection, thereby reducing penetration force and increasing the fuel's directivity and atomization quality.
Implementation Method 1
When the fuel passes through the outlet-channel-forming portion having a relatively large surface roughness, the fuel flow is easily disturbed. When the fuel of which flow has been disturbed is injected from the outflow port, the fuel is atomized by being diffused in various directions.
Implementation Method 2
when passing through the outlet channel, the fuel tends to flow along the groove. Since the fuel flows along the groove, the fuel spreads in the radial direction of the injection hole and the liquid film tends to become thin.
Data Source
AI summary
In a fuel injection device including a body portion that forms an injection hole through which a fuel is injected, the body portion includes an inlet-channel-forming portion that is connected to an inflow port of the fuel in the injection hole and forms an inlet channel which is a fuel flow channel, and an outlet-channel-forming portion that is connected to the inlet channel and an outflow port of the fuel in the injection hole, and forms an outlet channel that is a fuel flow channel. A surface roughness of the outlet-channel-forming portion is larger than a surface roughness of the inlet-channel-forming portion.