Hydrogen Fuel Injector With Eddy-Current Valve Damping
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Solution Overview
Problem
Hydrogen combustion engines face challenges such as low wear resistance, unpredictable fuel mass flow, and high wear due to valve bounce, which affect robustness and durability, particularly in direct injection systems.
Innovation Solution
A fuel injector design incorporating a passive valve with a reciprocating plunger made of a permanent magnet and an electrically conductive, non-magnetizable plunger guide, utilizing eddy currents to induce a magnetic field that opposes the movement of the plunger, reducing impact speed and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a passive valve with reciprocating plunger is used in hydrogen direct injection, then the injection speed can be increased, but valve bounce and wear increase due to lack of damping
Solution Approach 1:
The patent replaces the traditional mechanical damping system (mechanical stops and guides) with an electromagnetic damping system. The plunger is equipped with a magnet that interacts with the conductive plunger guide to generate eddy currents, which provide passive damping without mechanical contact during the critical injection phase, thereby reducing valve bounce and wear while maintaining high injection speed.
Solution Approach 2:
The patent introduces a conductive plunger guide as an intermediary element between the plunger magnet and the external environment. This guide serves dual purposes: it provides structural guidance for the plunger movement and acts as a medium to generate electromagnetic damping forces through eddy currents, thereby controlling valve bounce without direct mechanical contact.
2Productivity
If high injection pressure is used to shorten injection duration, then combustion efficiency improves, but compression of hydrogen beforehand is required which decreases overall efficiency
Solution Approach 1:
The patent implements preliminary action by pre-compressing hydrogen in the plunger chamber before injection. The reciprocating plunger compresses the hydrogen fuel to high pressure in advance, storing energy that is then released during the injection phase. This eliminates the need for additional compression during injection, maintaining high combustion efficiency while avoiding energy losses from repeated compression.
3Manufacturing precision
If the plunger moves quickly to achieve smooth injection rate, then fuel mass flow predictability improves, but impact speed against stops increases causing more wear
Solution Approach 1:
The patent replaces mechanical damping (physical contact with stops and guides) with electromagnetic damping. The magnet on the plunger interacts with the conductive plunger guide to generate eddy currents that provide passive damping forces, reducing valve bounce and impact speeds without compromising injection rate smoothness or requiring mechanical contact during operation.
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 injector robustness by reducing wear and ensuring a smooth injection rate, improving durability and predictability of the fuel mass flow.
Implementation Method 1
a reciprocating plunger (or valve insert) of the passive valve comprises or is a permanent magnet, and a plunger guide is provided for guiding the reciprocating movement of the plunger, which is electrically conductive and non-magnetizable or only weakly magnetizable
Implementation Method 2
utilizing eddy currents to induce a magnetic field that opposes the movement of the plunger
Data Source
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AI summary
The present invention relates to an injector for injecting fuel, preferably for directly blowing in a gaseous fuel, in particular hydrogen, comprising a fuel feed line for introducing a gaseous fuel which is under high pressure, an actively switchable active valve, which is designed to close or release at least one passage in order to either permit or interrupt a flow connection from the fuel feed line to a region downstream of the active valve, and a passive valve which is arranged downstream of the active valve and is passively switchable by different pressure ratios prevailing upstream and downstream of the passive valve into a closing or releasing state in order to either permit or interrupt a flow connection from upstream of the passive valve to a region downstream of the passive valve. The invention is further characterized in that a reciprocating tappet of the passive valve comprises a permanent magnet or is a permanent magnet, and that a tappet guide for guiding the reciprocating movement of the tappet is provided, said tappet guide being electrically conductive and non-magnetizable or only weakly magnetizable.