Hydrogen Internal Combustion Engine NOx Catalyst Regeneration
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Solution Overview
Problem
Existing hydrogen-powered internal combustion engines face challenges in managing nitrogen oxide emissions due to the complexity of regeneration processes and the need for continuous reducing agent supply, which can lead to emissions if not controlled properly.
Innovation Solution
A method for operating an internal combustion engine using hydrogen fuel with a nitrogen oxide storage catalyst, alternating between lean and rich air/hydrogen mixtures to store and regenerate nitrogen oxides, reducing the need for continuous reducing agent supply and simplifying the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If selective catalytic reduction process is used to reduce NOx emissions, then NOx emissions are reduced, but continuous supply of reducing agent is required which complicates the system and may lead to emissions if control fails
Solution Approach 1:
The nitrogen oxide storage catalyst performs self-regeneration by storing NOx during lean combustion and releasing it during rich combustion cycles, eliminating the need for external reducing agent supply systems. The system uses its own operational cycles (lean/rich alternation) to regenerate the catalyst without requiring separate dosing equipment.
Solution Approach 2:
The catalyst operates in periodic cycles alternating between lean and rich combustion modes. During lean phases, NOx is stored; during rich phases, the stored NOx is reduced and released. This periodic operation enables self-regeneration without continuous reducing agent supply.
2Object-generated harmful factors
If nitrogen oxide storage catalyst is used to store NOx, then NOx emissions are reduced, but regeneration requires complex control and multiple fuels
Solution Approach 1:
Hydrogen fuel serves multiple functions: it is the primary fuel for power generation, and it also acts as the reducing agent for catalyst regeneration. The same fuel supply system provides hydrogen for both combustion power and NOx reduction, eliminating the need for separate reducing agent systems and simplifying control.
Solution Approach 2:
The air-to-fuel ratio parameter is alternated between lean and rich conditions to control catalyst operation. By changing this single parameter, the system achieves both NOx storage (during lean phases) and regeneration (during rich phases), simplifying control compared to systems requiring multiple fuel types.
3Productivity
If lean air/hydrogen mixture is combusted continuously, then engine efficiency increases and NOx formation is reduced, but nitrogen oxide storage catalyst saturation occurs over time requiring regeneration
Solution Approach 1:
The system alternates between lean combustion (for efficiency and NOx reduction) and rich combustion (for catalyst regeneration). This periodic switching maintains high overall efficiency while preventing catalyst saturation, extending the effective operational duration of the storage catalyst.
Solution Approach 2:
The catalyst provides continuous NOx reduction capability through alternating storage and regeneration cycles. By maintaining the catalyst in an active state through periodic regeneration, the system ensures continuous harmful factor reduction without interrupting the lean combustion operation that provides efficiency.
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 allows for reliable nitrogen oxide storage and regeneration, minimizing emissions and system complexity by utilizing hydrogen's synergy effects, enabling efficient operation with reduced nitrogen oxide formation and eliminating the need for additional exhaust aftertreatment systems.
Implementation Method 1
an internal combustion engine has at least one nitrogen oxide storage catalyst through which the discharged exhaust gas flows
Implementation Method 2
Internal combustion engines operated in this way only produce thermal nitrogen oxides as harmful combustion products
Implementation Method 3
in the second operating state a rich air/hydrogen mixture is burned in the at least one combustion chamber
Data Source
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AI summary
The invention relates to a method for operating an internal combustion engine (2), wherein the internal combustion engine (2) comprises at least one combustion chamber (3) in which a fuel is at least partially burned with ambient air, an exhaust tract (6) that is fluidically coupled to an outlet side (7b) of the at least one combustion chamber (3), wherein hydrogen is used as fuel for the internal combustion engine (2), wherein the internal combustion engine (2) also has at least one NOx storage catalyst (13) and an exhaust gas discharged from the at least one combustion chamber (3) into the exhaust tract (6) at least partially, preferably entirely, flows through the at least one NOx storage catalyst (13), wherein a lean hydrogen-air mixture is burned in the at least one combustion chamber (3) in a first operating state, wherein the NOx storage catalyst (13) is regenerated in a second operating state. In order to easily operate the internal combustion engine as a low-emissions system, a rich hydrogen-air mixture is burned in the at least one combustion chamber (3) in the second operating state.