Dual Gas Metering for Hydrogen Engine Premature Ignition Control
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Solution Overview
Problem
Internal combustion engines operating with gas mixtures of high flame speeds and low ignition energies, such as those containing hydrogen, face risks of premature ignition and damage due to the high flammability and rapid combustion propagation, which existing fuel metering systems struggle to manage safely and cost-effectively.
Innovation Solution
A dual fuel metering system is employed, comprising a first gas metering device for pulsed, combustion chamber-adjacent fuel injection and a second gas metering device for continuous intake manifold fuel injection, with the flow velocity in the intake tract exceeding the flame velocity under high loads to prevent combustion propagation, and a control mechanism to switch between these systems based on load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gas mixtures with high flame speeds and low ignition energies (e.g., hydrogen-air mixtures) are used in internal combustion engines, then the engine power and efficiency are improved, but the risk of premature ignition and combustion propagation through the intake manifold increases
Solution Approach 1:
The patent divides the fuel gas supply system into two separate metering devices: one for metering fuel gas into the intake manifold and another for metering fuel gas close to the combustion chamber. This segmentation allows the system to supply fuel gas safely to the intake manifold while preventing excessive fuel gas accumulation that could lead to premature ignition and combustion propagation.
Solution Approach 2:
The patent introduces a control unit as an intermediary that coordinates the operation of multiple metering devices and monitors engine conditions. This control unit ensures that fuel gas is supplied safely by regulating the amount entering the intake manifold and coordinating with combustion chamber-adjacent metering, thereby preventing premature ignition while maintaining engine power.
2Ease of operation
If fuel gas is continuously supplied into the intake manifold, then the engine operation is simplified, but the flame speed of the gas mixture may exceed the flow velocity in the intake tract, allowing combustion propagation
Solution Approach 1:
The patent employs dynamic control of fuel gas supply by using multiple metering devices that can adjust their operation based on engine load and operating conditions. The control unit dynamically regulates the amount of fuel gas supplied to the intake manifold versus direct combustion chamber injection, ensuring that the gas mixture's flame speed remains below the flow velocity in the intake tract while maintaining simplified operation.
Solution Approach 2:
The patent changes the operational parameters of the fuel supply system by introducing a second metering device that operates in conjunction with the first. This allows the system to vary the distribution of fuel gas between intake manifold supply and direct combustion chamber injection based on operating conditions, preventing combustion propagation while maintaining ease of operation through automated control.
3Device complexity
If a single fuel metering system is used for all operating conditions, then the device complexity is reduced, but the wear on fuel injectors increases and lifespan is reduced
Solution Approach 1:
The patent segments the fuel gas metering function into multiple dedicated devices: one metering device for intake manifold supply and another for combustion chamber-adjacent injection. This segmentation distributes the wear and operational stress across multiple components rather than concentrating it on a single injector, extending overall system lifespan while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The control unit acts as an intermediary that manages the coordinated operation of multiple metering devices. By distributing the fuel supply task across multiple specialized components and managing their operation based on conditions, the system reduces wear on individual injectors and extends their lifespan while keeping the overall system complexity manageable through centralized control.
4Reliability
If combustion chamber-adjacent fuel gas metering is used exclusively, then safety against premature ignition is improved, but the cost-effectiveness and simplicity of the system are reduced
Solution Approach 1:
The patent segments the fuel supply system into two metering devices with distinct functions, where one device supplies fuel gas to the intake manifold and another supplies fuel gas close to the combustion chamber. This segmentation maintains safety against premature ignition through combustion chamber-adjacent metering while improving cost-effectiveness by allowing the intake manifold metering device to operate under safer conditions, extending component lifespan and reducing maintenance costs.
Solution Approach 2:
The control unit serves as an intermediary that coordinates the operation of multiple metering devices to achieve both safety and cost-effectiveness. By managing the distributed fuel supply system, the control unit ensures that combustion chamber-adjacent metering provides safety while the divided architecture improves cost-effectiveness through reduced wear on individual components and optimized fuel distribution.
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
This approach ensures safe and cost-effective operation across various load ranges by minimizing premature ignitions and reducing wear on fuel injectors, extending their lifespan and maintaining engine safety and efficiency.
Implementation Method 1
a first gas metering device for the pulsed, combustion chamber-adjacent metering of a fuel gas with several gas injectors assigned to the cylinders
Implementation Method 2
a second gas metering device for the continuous, central metering of a fuel gas into the intake manifold
Implementation Method 3
the flow velocity in the intake tract, particularly in an exhaust cross-section of the intake tract, is higher than the flame velocity of the gas mixture
Implementation Method 4
The gas injector meters the fuel gas into the intake port belonging to each cylinder. The amount of fuel gas is determined by how long a gas injector is open to allow fuel gas to pass through.
Data Source
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AI summary
The present invention relates to a method for operating an internal combustion engine (2) with gas mixtures of high flame speeds and low ignition energy, in particular hydrogen-air mixtures, comprising a plurality of cylinders (4), an intake tract (6) through which intake air enters the cylinders (4) of the internal combustion engine (2), a first gas metering device (20) for intermittently metering a fuel gas near the combustion chamber with several gas injectors (22) assigned to the cylinders (4), and a second gas metering device (24) for continuously metering a fuel gas far from the combustion chamber into the intake tract (8) for all cylinders (4), wherein the metering of the fuel gas in a first load range of low load is carried out exclusively by the first gas metering device (20) and in a second load range of high load is carried out at least mainly by the second gas metering device (24).