Hydrogen Injector Nozzle Cap Overlap for Jet Stability and Pressure
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Solution Overview
Problem
Hydrogen nozzles in hydrogen internal combustion engines face challenges in maintaining the initial direction of the jet due to the need for larger exit areas, leading to vortices and potential auto-ignition of residual gases, which complicates the control of hydrogen flow.
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, allowing for a smaller outlet area and improved control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the nozzle cap exit area is increased to accommodate sonic or supersonic hydrogen flow, then the hydrogen flow rate is improved, but the ability to maintain jet direction and control flow is worsened
Solution Approach 1:
The nozzle cap is designed with locally differentiated surface features: a generally smooth inner surface in the upstream region and a textured or roughened inner surface in the downstream region. This local quality variation creates controlled turbulence and eddy currents that redirect hydrogen flow along the nozzle cap surface, maintaining jet directionality despite the large exit area required for high flow rates
Solution Approach 2:
The textured surface of the nozzle cap acts as an intermediary between the hydrogen flow and the combustion chamber environment. This intermediate surface structure generates eddy currents that serve as a mediator to redirect the hydrogen jet, preventing direct collision with residual gases while maintaining controlled flow direction
2Quantity of substance
If the nozzle cap exit area is increased, then hydrogen flow capacity is improved, but vortex formation and residual gas auto-ignition risk increase
Solution Approach 1:
The design converts the potentially harmful large exit area that causes vortex formation into a beneficial feature by intentionally creating a textured surface that generates controlled eddy currents. These eddy currents, which would otherwise be considered harmful vortices, are redirected to serve a useful function by guiding the hydrogen jet away from residual gases, thus converting the harm into a protective mechanism
Solution Approach 2:
The solution moves the flow control mechanism from the traditional axial dimension to the radial dimension by using the nozzle cap's lateral surface texture to generate circumferential eddy currents. This dimensional shift allows the hydrogen jet to be redirected along the nozzle cap surface in a controlled manner, preventing harmful vortices while maintaining flow capacity
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 hydrogen flow control, increases pressure by up to 100%, and optimizes piston bowl design, reducing the risk of jet collapse and auto-ignition, while facilitating uniform mixing with air.
Implementation Method 1
the valve protrusion and the nozzle protrusion at least partly overlap in a radial direction... guiding the hydrogen flow to maintain direction and increase pressure
Data Source
AI summary
A fuel injection arrangement admits a flow of hydrogen into a combustion chamber of hydrogen internal combustion engine. The fuel injection arrangement has 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. The nozzle protrusion is arranged axially between a valve protrusion of the inlet valve arrangement and an outlet of the nozzle cap. The valve protrusion and the nozzle protrusion at least partly overlap in a radial direction.