Fuel Injection Valve Needle Tip Curvature for Uniform Spray
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Solution Overview
Problem
Blind hole nozzles in fuel injection valves suffer from reduced effective injection pressure due to swirling fuel between the valve sealing surface and body seat, leading to uneven fuel distribution and optimized inlet only at some injection openings.
Innovation Solution
A conical valve sealing surface with a concavely curved needle tip and an outwardly curved crest or flat end face, ensuring fuel flow separation and deflection for high-speed fuel exit at injection openings, optimizing inlet and reducing turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a blind hole nozzle is used to distribute fuel evenly to injection openings, then spray pattern uniformity is improved, but effective injection pressure is reduced due to fuel swirling between the valve sealing surface and body seat
Solution Approach 1:
The needle tip is designed with a concave curvature that matches the conical angle of the blind hole wall. This curved surface guides the fuel flow smoothly into the blind hole, preventing detachment and reducing turbulence. The curvature allows the fuel to follow the needle tip contour, maintaining attachment and preserving injection pressure while achieving uniform distribution to all injection openings.
2Loss of energy
If a needle tip with conical sealing surface and convex then concave area is used to direct fuel flow, then turbulence is reduced, but the shape cannot be adapted to injection openings with different angles
Solution Approach 1:
The needle tip features a concave area with a specific curvature radius that is locally optimized to match the conical angle of the blind hole wall. This local geometric adaptation allows the fuel flow to attach smoothly to the needle tip surface at the specific angle required by the blind hole configuration, reducing turbulence while being specifically tailored to the injection opening geometry.
3Manufacturing precision
If the valve needle protrudes into the blind hole to optimize inlet at some holes, then inlet optimization is achieved, but other injection openings receive unfavorable flow
Solution Approach 1:
The concave needle tip design serves multiple functions simultaneously: it acts as a sealing surface, a flow guide, and a turbulence reducer. The universal concave curvature geometry works effectively for all injection openings around the blind hole, providing consistent flow optimization and uniform fuel distribution to all openings regardless of their angular position.
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 effective injection pressure and uniformity by ensuring high-speed fuel exit at all injection openings, minimizing energy loss and improving spray pattern consistency.
Implementation Method 1
the fuel flow separates from the valve needle as it enters the blind hole, but is then deflected by the further downstream part of the needle tip
Implementation Method 2
the fuel, which passes between the valve sealing surface and the body seat, is swirled when passing into the blind hole
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a fuel injection valve for internal combustion engines having a valve body (1) in which a blind hole (10) is formed, with at least one injection opening (7) proceeding from said blind hole (10). A longitudinally displaceable needle (5) is arranged in the valve body (1), with a valve sealing face (11) being formed at that end of said valve needle (5) which faces towards the blind hole (10), said valve sealing face (11) being formed from one or more conical faces, and the valve needle (5) interacting, by means of a body seat (9), with said valve sealing face (11) to control a fuel flow to the at least one injection opening (7). A needle tip (30) adjoins the valve sealing face (11), said needle tip (30) dipping into the blind hole (10) when the valve needle (5) bears against the body seat (9), the needle tip (30) being curved in a concave fashion directly adjacent to the valve sealing face (11).