Internal Combustion Engine Pre-Chamber Hydrogen Ignition Control
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Solution Overview
Problem
Internal combustion engines with pre-chambers face high thermal loading and increased risk of early, unintended ignitions when using hydrogen as fuel, due to higher combustion temperatures and increased combustibility.
Innovation Solution
The engine is configured with a pre-chamber in fluid connection with the main combustion chamber, where fuel injectors are strategically placed to enrich the air-fuel mixture in the main combustion chamber with a lower ignition delay than in the pre-chamber, and to supply the pre-chamber with an air-fuel mixture having a higher ignition delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydrogen is used as fuel in the pre-chamber, then the combustion efficiency and energy density are improved, but the thermal load on the pre-chamber and risk of early ignitions increase
Solution Approach 1:
The engine is divided into two separate combustion zones: a pre-chamber for hydrogen combustion and a main combustion chamber for hydrocarbon combustion. This segmentation allows each zone to be optimized for its specific fuel type, preventing the thermal and ignition issues that would occur if hydrogen were combusted in the pre-chamber of a conventional engine.
Solution Approach 2:
Different fuel types are assigned to different spatial locations: hydrogen is supplied to the pre-chamber while hydrocarbon fuel is supplied to the main combustion chamber. This local differentiation of fuel quality matches the specific combustion characteristics and thermal requirements of each zone, resolving the thermal load problem.
2Use of energy by moving object
If hydrogen is used as fuel, then the energy content is improved, but the risk of early, unintended ignitions increases due to higher combustibility
Solution Approach 1:
By separating the combustion functions into two distinct chambers, the system prevents uncontrolled hydrogen combustion in the pre-chamber. The main combustion chamber serves as a controlled zone for hydrocarbon combustion, while the pre-chamber is dedicated to hydrogen ignition, eliminating the reliability issues of mixed-fuel combustion.
Solution Approach 2:
The pre-chamber acts as an intermediary zone that conditions the hydrogen combustion separately from the main combustion process. This intermediate combustion zone prevents direct interaction between hydrogen and the main combustion chamber's thermal field, thereby preventing early ignitions.
3Reliability
If the pre-chamber is flushed with fuel gas to enrich the mixture, then the ignition properties are improved, but the thermal loading of components increases
Solution Approach 1:
The fuel enrichment function is segmented and performed separately in the pre-chamber using hydrogen, rather than enriching the main combustion chamber mixture. This separate enrichment process improves ignition properties without subjecting the main combustion components to excessive thermal loading.
Solution Approach 2:
The air-fuel ratio is changed locally in the pre-chamber by introducing hydrogen, creating an enriched mixture with improved ignition properties. This parameter change is confined to the pre-chamber volume, preventing thermal loading propagation to other components.
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 configuration reduces the thermal load on the pre-chamber and decreases the risk of early, unintended ignitions while allowing for the use of hydrogen as fuel.
Implementation Method 1
at least one fuel injector is arranged in the intake port, the intake manifold and/or the main combustion chamber in such a way that the air and/or air-fuel-mixture supplied to the main combustion chamber can be enriched
Implementation Method 2
a pre-chamber (4) which is in fluid connection with the main combustion chamber (12)
Implementation Method 3
the combustion of hydrogen or hydrogen enriched air-fuel-mixture generates higher temperatures
Data Source
AI summary
An internal combustion engine comprising: a main combustion chamber comprising at least one intake valve and at least one exhaust valve, wherein at least one intake port fluidically connected to an intake manifold is configured to supply an air and/or an air-fuel-mixture to the main combustion chamber via the at least one intake valve, and a pre-chamber which is in fluid connection with the main combustion chamber, wherein the pre-chamber is in fluid connection with the intake port and/or the intake manifold through a supply line, wherein at least one fuel injector is configured to enrich the air and/or air-fuel-mixture supplied to the main combustion chamber to have a lower ignition delay than an air-fuel-mixture supplied to the pre-chamber and/or air or air-fuel-mixture can be supplied to the pre-chamber to have a higher ignition delay than an air-fuel-mixture supplied to the main combustion chamber.