Ammonia Engine Fuel Reforming Using Exhaust Heat Cracking
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Solution Overview
Problem
Existing internal combustion engine systems using ammonia as a fuel suffer from carbon emissions, and have an overall relatively low reactivity as a fuel, requiring significant energy for conversion to hydrogen and adding complexity, weight, and cost to vehicles.
Innovation Solution
An internal combustion engine system that uses exhaust gases to crack ammonia into nitrogen and hydrogen efficiently, supplying these gases to the engine with adjustable ratios through separate fuel channels, and optionally using ammonia directly as fuel, with a fuel reforming arrangement and control system to optimize combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ammonia is converted to hydrogen through thermal decomposition or catalytic cracking, then combustible hydrogen is obtained, but significant energy is required and overall efficiency is reduced
Solution Approach 1:
The system performs preliminary cracking of ammonia to hydrogen in a reformer unit before combustion, but uses preliminary heating of the reformer catalyst by exhaust gases to eliminate the need for external energy input. This preliminary action is self-sustaining and does not reduce overall efficiency.
Solution Approach 2:
The exhaust gases from the engine are used to selfheat the reformer catalyst, making the cracking process self-sustaining. The system serves itself by using its own waste heat to enable the fuel conversion process, eliminating the need for external energy input and maintaining overall efficiency.
2Reliability
If ammonia is converted to hydrogen through thermal decomposition or catalytic cracking, then combustible hydrogen is obtained, but extra systems are required adding complexity, weight and costs
Solution Approach 1:
The reformer unit is integrated with the exhaust system, merging the fuel conversion function with the existing exhaust pathway. The reformer is positioned to receive exhaust heat directly, combining thermal management and fuel processing into a single integrated component rather than separate systems.
Solution Approach 2:
The reformer unit serves multiple functions: it cracks ammonia to hydrogen, is heated by exhaust gases to maintain reaction temperature, and the cracked ammonia/hydrogen mixture is then supplied to the engine. This multi-functionality reduces the need for separate components and simplifies the overall system architecture.
3Object-affected harmful factors
If ammonia is used as fuel, then no carbon emissions are produced, but ammonia has low reactivity and requires hydrogen assistance for combustion
Solution Approach 1:
The system changes the chemical composition parameters of the fuel by cracking ammonia into a mixture of hydrogen and cracked ammonia in specific ratios. This parameter change transforms the low-reactivity ammonia into a high-reactivity fuel blend suitable for compression ignition engines while maintaining zero carbon emissions.
Solution Approach 2:
The system creates a composite fuel from cracked ammonia and hydrogen in controlled ratios. This composite fuel combines the carbon-free advantage of ammonia with the high reactivity and combustion properties of hydrogen, achieving both low emissions and reliable combustion characteristics.
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 energy efficiency, reduces system complexity, and improves ammonia's flammability properties, allowing for compact and efficient ammonia-based engine operation.
Implementation Method 1
crack (e.g. at around 425 °C), by use of (only) heat from said exhaust gases in the fuel reforming arrangement, the ammonia into cracked ammonia comprising nitrogen and hydrogen. The fuel reforming arrangement may be nickel based, or be based on any other suitable catalyst material for cracking ammonia efficiently.
Implementation Method 2
Ammonia can be converted to hydrogen (H2) through thermal decomposition or catalytic cracking, which is the most common means of hydrogen generation from ammonia.
Implementation Method 3
a heat exchanger (3b) having a first end being connected to the reformer (3a) and a second end being connected to the primary fuel line (9) upstream of the reformer (3a), wherein the system is configured to preheat, by the heat exchanger (3b), the ammonia using the exhaust gases.
Implementation Method 4
The system is configured to supply at least one of said hydrogen and said nitrogen to said ICE from the fuel reforming arrangement via the fuel control arrangement. Furthermore, the system is configured to supply air to said ICE from said air-supply channel. The air may react with the fuel at the inlet manifold or cylinders.
Data Source
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AI summary
The present disclosure relates to an internal combustion engine, ICE, system (1) comprising an internal combustion engine (2), an ammonia tank (4), an air supply channel (6) connected to said ICE (2) for supplying air to said ICE (2) and a fuel reforming arrangement (3). Further, the system (1) comprises a fuel control arrangement (8) comprising at least a first fuel supply channel (8a) being connected between a second part of said fuel reforming arrangement (3) and said ICE (2). The system (1) is configured to: supply ammonia to said fuel reforming arrangement (3) and crack, by use of heat from said exhaust gases in the fuel reforming arrangement (3), the ammonia into cracked ammonia comprising nitrogen and hydrogen. Further, the system (1) is configured to supply air and at least one of said hydrogen and said nitrogen to said ICE (2) from the fuel reforming arrangement (3) via the fuel control arrangement (8).