Hydrogen Injector Nozzle Geometry for Stable Jet Direction
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Solution Overview
Problem
Hydrogen nozzles in hydrogen internal combustion engines face challenges in maintaining the initial direction of the jet, leading to vortices and auto-ignition risks due to larger nozzle cap holes and uncontrolled flow directions, especially at sonic or supersonic speeds.
Innovation Solution
A fuel injection arrangement with a nozzle cap featuring a valve protrusion and nozzle protrusion that overlap radially, guiding the hydrogen flow to maintain direction and increase pressure, using a smaller outlet area to enhance control and reduce the risk of auto-ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the nozzle cap hole exit area is increased to accommodate sonic or supersonic hydrogen flow, then the hydrogen flow rate is improved, but the ability to control jet direction and velocity deteriorates
Solution Approach 1:
The nozzle cap incorporates multiple holes with different geometries (circular, slot-shaped, irregular) distributed at specific locations. Each hole type creates distinct flow patterns - circular holes produce concentrated jets for penetration, while slot-shaped holes generate broader spray patterns. This local differentiation of hole characteristics enables simultaneous achievement of high flow rate and directional control.
Solution Approach 2:
The single large nozzle opening is segmented into multiple smaller holes of varying sizes and shapes. This segmentation allows independent optimization of each hole's contribution to the overall spray pattern, enabling precise control over jet direction and velocity while maintaining high total hydrogen flow rate through the combined effect of multiple openings.
2Quantity of substance
If the nozzle cap hole exit area is increased, then hydrogen flow rate is improved, but vortex formation and flow instability increase
Solution Approach 1:
Different hole geometries are strategically placed to address specific flow stability issues. Slot-shaped holes reduce vortex formation compared to circular holes, while irregularly shaped holes create specific flow patterns that enhance mixing. This local optimization of hole characteristics stabilizes the overall hydrogen flow while maintaining high flow rate.
3Quantity of substance
If the nozzle cap hole exit area is increased, then hydrogen flow rate is improved, but the risk of auto-ignition from residual gases increases
Solution Approach 1:
The design extracts and eliminates the problematic cap-volume reservoir by using multiple small holes that open directly into the combustion chamber. This eliminates the trapped residual hydrogen-containing gases that could auto-ignite, while still achieving high hydrogen flow rate through the combined area of multiple openings.
4Ease of manufacture
If conventional pintle-valve nozzle design is used, then manufacturing is simplified, but the ability to direct jet at desired velocity and direction deteriorates
Solution Approach 1:
The nozzle cap uses simple geometric hole patterns (circular, slot-shaped, irregular) that are straightforward to manufacture using conventional machining or forming processes. Despite the simplicity of individual hole shapes, the strategic arrangement and combination of different hole types provide sophisticated control over jet direction and velocity, achieving complex flow control without complex manufacturing.
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 solution provides improved control over hydrogen flow, increasing pressure by up to 100% and reducing the risk of vortices and auto-ignition, allowing for optimized piston bowl design and uniform mixing with air.
Implementation Method 1
By providing a valve protrusion on the inlet valve arrangement and a nozzle protrusion on the nozzle cap as defined above, the flow of hydrogen is obliged to follow the flow guiding portion of the inlet valve arrangement in a more satisfactory manner... the injection pressure of the hydrogen can be increased
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present invention relates to a fuel injection arrangement for admitting a flow of hydrogen into a combustion chamber of hydrogen internal combustion engine. The fuel injection arrangement comprises a nozzle cap and an inlet valve arrangement. An inner surface of the nozzle cap comprises a nozzle protrusion protruding radially towards an envelope surface of a flow guiding portion of the inlet valve arrangement, wherein the nozzle protrusion is arranged axially between a valve protrusion of the inlet valve arrangement and an outlet of the nozzle cap, wherein the valve protrusion and the nozzle protrusion at least partly overlap in a radial direction.