System and method for an internal combustion engine using ammonia as a fuel source and heat exchange medium for engine cooling

Abstract

This relates to a system and method for generating hydrogen from ammonia on a vehicle. [Solution] The present invention relates to a system and method for producing hydrogen from ammonia on a vehicle, wherein the produced hydrogen is used together with ammonia as a fuel source for an internal combustion engine. The present invention utilizes ammonia not only as a co-fuel for the engine but also as a heat exchange medium used in a cooling system for the internal combustion engine, thereby transferring heat from the high-temperature engine coolant to the ammonia, which cools the engine coolant and preheats the ammonia into a gaseous state, providing a system and method for producing hydrogen from ammonia on a vehicle for use as a fuel source for an internal combustion engine.

Description

[Technical Field]

[0001] [Cross-reference of related applications] This application relates to U.S. Provisional Patent Application No. 63 / 395,820, filed on August 6, 2022, entitled "Systems and Methods for the Catalytic Production of Hydrogen from Ammonia on-Board Motor Vehicles," U.S. Provisional Patent Application No. 63 / 355,959, filed on June 27, 2022, entitled "Systems and Methods for the Catalytic Production of Hydrogen from Ammonia on-Board Motor Vehicles," and "Systems and Methods for the Catalytic Production of Hydrogen from Ammonia on-Board Motor Vehicles." This is a continuation application to U.S. Patent No. 11,840,449, filed on November 14, 2022, claiming the interests of U.S. Provisional Patent Application No. 63 / 312,121, filed on February 21, 2022, entitled "VEHICLES," and also claims the interests of U.S. Patent No. 11,840,449, filed on September 1, 2023, entitled "SYSTEMS AND METHODS FOR THE ON-BOARD CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA USING A HEAT EXCHANGE CATALYST UNIT AND AN ELECTRIC CATALYST UNIT OPERATING IN SERIES," entitled "SYSTEMS AND METHODS FOR THE ON-BOARD CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA USING A HEAT EXCHANGE CATALYST UNIT AND AN ELECTRIC CATALYST UNIT OPERATING IN SERIES," filed on September 1, 2023.This is a continuation-in-part of and claims the benefit of U.S. Non-Provisional Application No. 18 / 660,466, filed May 10, 2024, entitled "SYSTEMS AND METHODS FOR ENGINE-MOUNTED CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA FOR USE AS A COMBUSTION FUEL", which is a continuation-in-part of and claims the benefit of the same, and all of these are jointly owned, and each disclosure is hereby incorporated by reference in its entirety.

[0002] The present invention generally relates to systems and methods for producing hydrogen from ammonia on a vehicle, where the produced hydrogen is used as a fuel source for an internal combustion engine, and where ammonia is used as a heat exchange medium for the cooling system of the internal combustion engine. BACKGROUND OF THE INVENTION

[0003] The overall increase in temperature on and above the Earth's surface represents a significant challenge that the Earth is facing. The Earth's climate has changed significantly mainly due to human activities, and the transportation sector plays a prominent role in this global warming. For example, internal combustion engines have conventionally burned fossil fuels, thereby generating CO2, a known factor in global warming. Over the past decade, the transportation sector has advanced in making electric and hybrid vehicles widely available. Most electric and hybrid vehicles sold today tend to produce significantly fewer global warming emissions than most vehicles operating on fossil fuels, i.e., gasoline. However, the environmental benefits of electric and hybrid vehicles still mainly depend on how much fossil fuel is burned to charge these vehicles. For example, if a vehicle is charged using a coal-heavy power grid, the environmental benefits are reduced.

[0004] Furthermore, batteries and fuel cells in electric vehicles rely on raw materials such as cobalt, lithium, and rare earth elements. These materials are linked to serious environmental and human rights issues. Cobalt, for example, is particularly problematic. When cobalt is mined, harmful tailings and slag that can leach into the environment are produced, and studies have found that communities surrounding cobalt mining and processing facilities have high rates of exposure to cobalt and other metals. Extracting these metals from their ore also requires a process called smelting, which can release sulfur oxides and other harmful air pollutants.

[0005] In light of the ongoing environmental problems associated with electric vehicles, ammonia has been proposed as a fossil fuel alternative for use in internal combustion engines, given its relatively high energy density and zero CO2 emissions when burned. However, pure ammonia burns too slowly to complete combustion during the power stroke of a four-stroke engine operating at several thousand revolutions per minute (RPM). Therefore, pure ammonia cannot be efficiently used as a fuel in small internal combustion engines, whether spark-ignited (i.e., gasoline) or compression-ignited (i.e., diesel). In other words, when ammonia burns, the combustion produces a flame with a relatively low propagation speed. This low combustion speed of ammonia makes combustion unstable under operating conditions of low engine load and high engine speed.

[0006] Previous approaches to refueling combustion engines with ammonia or hydrogen alone required mixing the ammonia or hydrogen with a secondary combustion-enhancing fuel such as gasoline, liquefied petroleum, or diesel. However, the requirements for the secondary combustion-enhancing fuel change with fluctuating engine load and speed, which can lead to control problems. Therefore, the use of secondary combustion-enhancing fuels typically requires additional control mechanisms, which must be part of the engine management system.

[0007] Furthermore, even when used as a secondary combustion-enhancing fuel as described in U.S. Patent No. 4,480,595 by Hobby et al., the use of fossil fuels does not achieve zero carbon emissions, and under any circumstances, the use of fossil fuels as a fuel source increases the greenhouse effect and contributes to global warming.

[0008] Hydrogen is also extremely abundant, and considering its lower heating value, it can rival the power of gasoline or diesel, making it a proposed alternative to fossil fuels for use in internal combustion engines. Hydrogen is known to ignite easily due to its high flame velocity and low ignition temperature, burning approximately six times faster than gasoline. Most importantly, hydrogen produces zero CO2 emissions when burned.

[0009] However, the challenges of using hydrogen in vehicles are that it is an extremely light, low-density gas and cannot be stored as easily as liquid fossil fuels. Hydrogen requires compression, cooling, or a combination of both. The use of compressed hydrogen fuel tanks in vehicles inherently presents several safety issues, including the risk of pressure vessel failure, hydrogen leakage in a confined space, and similar risks.

[0010] It is known that hydrogen can be obtained from ammonia by catalytically decomposing ammonia into its constituent hydrogen and nitrogen components through a process called "cracking." However, the ammonia cracking process is an endothermic process that requires heat. When the power supply on a motor vehicle is limited, it is difficult to generate the heat necessary to efficiently perform ammonia cracking onboard.

[0011] Conventional catalytic units for vehicles, also known as catalytic converters, are well-known. These catalytic units typically have planar metal conductors that allow electric current to pass through. For example, Emitec Technologies GmbH (trademark), located in Lohmar, Germany, manufactures electrocatalytic converters used to treat exhaust gas emissions, which include spiral planar conductors. Such planar conductors are used for exothermic reactions.

[0012] The conductor can also take other forms, such as the honeycomb structure of the ammonia reforming device described in Takeuchi's U.S. Patent No. 11,421,629, which utilizes an exothermic reaction to produce hydrogen gas from ammonia gas.

[0013] However, the ammonia dissociation reaction is highly endothermic. Conventional catalytic converters typically have limited surface area to allow for an endothermic reaction that absorbs enough heat into the ammonia gas to provide efficient ammonia dissociation, given their inherently low length-to-diameter ratio.

[0014] Furthermore, conventional catalytic converters are primarily used to contain exhaust gases and are not designed to accommodate large pressures. As a result, there is no large pressure difference across the ends of these catalytic converter devices that need to be sealed. In addition, conventional catalytic converters are typically made from steel, such as elastomer steel, which may be prone to leakage and cannot be hermetically sealed. For the purpose of onboard ammonia dissociation, unsealed devices are unsuitable, given the risk of irritating heated ammonia and / or flammable hydrogen being exposed to the environment, vehicle components, and vehicle occupants.

[0015] Other systems that utilize an exothermic reaction to produce hydrogen from ammonia onboard burn ammonia to generate the heat required for the exothermic reaction. For example, Grannell's U.S. Patent Publication 20140105816 and Tange's U.S. Patent Publication 20140238316 describe ammonia cracking systems that rely on the combustion of ammonia, for example, by a flame cracker, to generate the heat required for ammonia decomposition.

[0016] In addition, various attempts have been made to optimize the cooling of engine components. For example, conventional engine cooling systems are designed to control ambient cooling airflow throughout the engine compartment to transfer a desired amount of heat away from the engine, transmission, and other heat-generating components. The engine cooling system thus maintains the engine's optimal operating temperature.

[0017] Such systems typically rely on a radiator mounted behind a grille positioned at the front of the vehicle. Generally, grilles and openings at the front of a vehicle tend to negatively impact the vehicle's aerodynamic characteristics, resulting in reduced fuel efficiency. Therefore, minimizing the number, profile, and size of such grilles and radiators is beneficial. However, reducing the size of these components may result in less efficient engine cooling.

[0018] Therefore, there is a need for systems and methods for producing hydrogen from ammonia on a vehicle for use as an internal combustion engine fuel source, which do not require fossil fuels as accelerators, co-fuels, additives, or auxiliary fuels, and which address the aforementioned challenges and drawbacks of vehicle cooling systems that rely primarily on ambient cooling airflow. [Overview of the project]

[0019] In one embodiment, the present invention relates to a system for heat exchange between ammonia and engine coolant for an internal combustion engine, the system comprising: an ammonia tank containing ammonia; a heat exchange unit fluidly coupled to the ammonia tank and the internal combustion engine, the heat exchange unit receiving ammonia from the ammonia tank; and a radiator fluidly coupled to the heat exchange unit and the internal combustion engine, the radiator receiving hot engine coolant from the internal combustion engine, and the radiator supplying the hot engine coolant to the heat exchange unit, wherein heat is transferred from the hot engine coolant to ammonia within the heat exchange unit, resulting in heated ammonia and cooled engine coolant, the heated ammonia exiting the heat exchange unit and being supplied to the internal combustion engine, and the cooled engine coolant exiting the heat exchange unit and being supplied to the radiator.

[0020] In another embodiment, the present invention relates to a system for heat exchange between ammonia and engine coolant for an internal combustion engine, the system comprising: an ammonia tank containing ammonia; and a heat exchange unit fluidly coupled to the ammonia tank and the internal combustion engine, the heat exchange unit receiving ammonia from the ammonia tank, and the heat exchange unit receiving hot engine coolant from the internal combustion engine, where heat is transferred from the hot engine coolant to ammonia within the heat exchange unit, resulting in heated ammonia and cooled engine coolant, where the heated ammonia and cooled engine coolant exit the heat exchange unit and are supplied to the internal combustion engine.

[0021] In yet another embodiment, the present invention is directed to a system for heat exchange between ammonia and an engine coolant for an internal combustion engine, the system comprising: an ammonia tank containing liquid ammonia; an expansion valve fluidly coupled to the ammonia tank, the expansion valve being capable of effecting a phase change of the liquid ammonia into a mixed-phase liquid and gaseous ammonia; and a heat exchange unit fluidly coupled to the expansion valve and to the internal combustion engine, the heat exchange unit being capable of receiving the mixed-phase liquid and gaseous ammonia from the expansion valve and the heat exchange unit being capable of receiving high-temperature engine coolant from the internal combustion engine, wherein the mixed-phase liquid and gaseous ammonia and the high-temperature engine coolant undergo heat exchange within the heat exchange unit, resulting in heated gaseous ammonia and cooled engine coolant, wherein the heated gaseous ammonia exits the heat exchange unit and is supplied to the internal combustion engine for use as a combustion co-fuel with hydrogen, and wherein the cooled engine coolant exits the heat exchange unit and is supplied to the internal combustion engine.

Brief Description of the Drawings

[0022] These and other embodiments of the present invention will be discussed with reference to the following exemplary and non-limiting figures, in which like elements are assigned like numbers.

[0023] [Figure 1] Perspective internal view of an exchange catalyst unit utilizing a TPMS structure.

[0024] [Figure 2] Perspective internal view of a heat exchange catalyst unit utilizing a TPMS structure, according to an embodiment of the present invention, showing the flow of heated exhaust gas and gaseous ammonia through a matrix.

[0025] [Figure 3] Perspective view of a matrix having a gyroidal TPMS structure, according to an embodiment of the present invention.

[0026] [Figure 4] Perspective view of a matrix having an orthogonal hole TPMS structure according to an embodiment of the present invention.

[0027] [Figure 5] Perspective view of a matrix having a split pea TPMS structure according to an embodiment of the present invention.

[0028] [Figure 6] Top perspective view of a heat exchange catalyst unit utilizing a TPMS structure according to an embodiment of the present invention.

[0029] [Figure 7] Front cross-sectional view of a cylindrical heat exchange catalyst unit utilizing a TPMS structure according to an embodiment of the present invention.

[0030] [Figure 8] Front cross-sectional view of a cylindrical heat exchange catalyst unit utilizing a TPMS structure according to an embodiment of the present invention, showing the flow of heated exhaust gas and gaseous ammonia through the matrix.

[0031] [Figure 9] Side cross-sectional view of a cylindrical heat exchange catalyst unit utilizing a TPMS structure according to an embodiment of the present invention, showing the flow of heated exhaust gas and gaseous ammonia through the matrix.

[0032] [Figure 10] Perspective view of a heat exchange catalyst unit utilizing a tube bundle structure according to an embodiment of the present invention.

[0033] [Figure 11] Front cross-sectional view of a heat exchange catalyst unit utilizing a tube bundle structure according to an embodiment of the present invention.

[0034] [Figure 12] Side cross-sectional view of a heat exchange catalyst unit utilizing a tube bundle structure according to an embodiment of the present invention.

[0035] [Figure 13] This is a front cross-sectional view of a two-pass heat exchange catalyst unit utilizing a tube bundle structure according to one embodiment of the present invention.

[0036] [Figure 14] This is a block diagram of an onboard ammonia cracking system for an internal combustion engine according to one embodiment of the present invention.

[0037] [Figure 15] This is a perspective view of an onboard ammonia cracking system for an internal combustion engine according to one embodiment of the present invention.

[0038] [Figure 16] This is a top perspective view of an onboard ammonia cracking system according to one embodiment of the present invention.

[0039] [Figure 17] This is a perspective side view of an onboard ammonia cracking system according to one embodiment of the present invention.

[0040] [Figure 18] This is a perspective view of an electrocatalytic unit according to one embodiment of the present invention.

[0041] [Figure 19] This is a cross-sectional view of an electrocatalytic unit according to one embodiment of the present invention.

[0042] [Figure 20] This is a perspective view of a dual onboard ammonia cracking system mounted in the internal combustion engine compartment of a motor vehicle, according to one embodiment of the present invention.

[0043] [Figure 21]This is a top view of a dual onboard ammonia cracking system mounted in the internal combustion engine compartment of a motor vehicle, according to one embodiment of the present invention.

[0044] [Figure 22] This is a side view of a dual onboard ammonia cracking system mounted in the internal combustion engine compartment of a motor vehicle, according to one embodiment of the present invention.

[0045] [Figure 23] This is a front view of a dual onboard ammonia cracking system mounted in the internal combustion engine compartment of a motor vehicle, according to one embodiment of the present invention.

[0046] [Figure 24] This is a block diagram of an engine cooling system according to one embodiment of the present invention, which includes a radiator and utilizes ammonia as a heat exchange medium.

[0047] [Figure 25] This is a block diagram of an engine cooling system according to one embodiment of the present invention, which does not have a radiator and uses ammonia as a heat exchange medium.

[0048] [Figure 26] A perspective view of the front of a vehicle with a grille, according to one embodiment of the present invention.

[0049] [Figure 27] A perspective view of a louver system for a grill according to one embodiment of the present invention.

[0050] [Figure 28] This flowchart shows a step in which a louver is activated based on the detected engine temperature according to one embodiment of the present invention.

[0051] [Figure 29]This is a block diagram of an engine cooling system according to one embodiment of the present invention, which has a radiator equipped with a bypass valve and uses ammonia as a heat exchange medium.

[0052] [Figure 30] This is a flowchart showing a step in one embodiment of the process of bypassing the radiator based on the detected engine temperature. Definition

[0053] The following definitions are intended to aid in the explanation and understanding of the terms defined in the context of this invention. These definitions are not intended to limit these terms to a narrower scope than those described throughout this specification. These definitions are intended to encompass grammatical equivalents.

[0054] As used herein, the term “motor vehicle” means any mobile vehicle capable of carrying one or more human occupants and / or cargo, or capable of performing work, and powered by any form of energy. The term “motor vehicle” includes, but is not limited to, (a) vehicles such as cars, trucks, vans, minivans, sports utility vehicles, passenger transport vehicles, cargo transport vehicles, two-wheeled, three-wheeled, and four-wheeled vehicles, quadricycles, motorcycles, scooters, all-terrain vehicles, utility task vehicles, and the like; (b) aerial vehicles such as helicopters, aircraft, airships, drones, aerospace vehicles, and the like; (c) vessels such as dry cargo ships, liquid cargo ships, special cargo ships, tugboats, cruise ships, recreational boats, fishing boats, personal watercraft, jet skis, and the like; (d) locomotives; and (e) heavy machinery and equipment, generators, lawnmowers and tractors, agricultural equipment and machinery, forestry equipment and machinery, construction equipment and machinery, mining equipment and machinery, and the like.

[0055] As used herein, the term “internal combustion engine” refers to any engine, spark-ignition gasoline engine, compression-ignition diesel engine, rotary, reciprocating, or other engine, in which combustion takes place in a combustion chamber, thereby performing work by the products of combustion, along with any other by-products, exerting force on a moving surface, from which mechanical output from the engine is obtained. The term “internal combustion engine” includes, but is not limited to, hybrid internal combustion engines, two-stroke engines, four-stroke engines, six-stroke engines, and similar types.

[0056] As used herein, the term “catalyst” refers to a material that facilitates a chemical reaction. The term “catalyst” includes, but is not limited to, one or more catalysts capable of facilitating a cracking reaction, such as ammonia cracking, whether used as a basic catalyst and / or an addition catalyst. For the purposes of the present invention, catalysts may include, but are not limited to, unstoichiometric lithium imide, nickel, iron, cobalt, iron-cobalt, ruthenium, vanadium, palladium, rhodium, platinum, sodium amide, and the like, as well as various combinations thereof.

[0057] As used herein, the terms “dissociation” and “cracking” refer to a process or a series of processes in which ammonia is dissociated and / or decomposed on at least one catalyst into its constituent hydrogen and nitrogen components.

[0058] As used herein, the term “nickel alloy” refers to pure nickel or an alloy containing nickel as a primary component. The term “nickel alloy” includes, but is not limited to, Inconel® products such as Inconel® 625, Inconel® 718, and Inconel® 725, and other composite metals having nickel as a primary component. Inconel® is a trademark of Special Metals Corporation, Huntington, West Virginia, and is a nickel-chromium superalloy often used in extreme environments where its components are exposed to high temperatures, high pressures, or mechanical loads.

[0059] As used herein, the term "triply-periodic minimal surface (TPMS)" refers to a mathematically defined, repeating structure in three dimensions with a mean curvature of zero and a large surface area.

[0060] As used herein, the term "ceramic" refers to silicon nitride ceramics, ceramic glass, steatite ceramics, quartz glass, glass, and other non-conductive ceramic materials.

[0061] As used herein, the term "lattice" refers to a structure in which unit cells are repeated at one or more points in a periodic arrangement, resulting in a structure that appears identical from any point.

[0062] As used herein, the terms “three-dimensional print” and “three-dimensionally printed” refer to a three-dimensional object obtained through an additive manufacturing process, wherein the object has height, width, and length. An additive manufacturing process involves the deposition, bonding, or solidification of material under computer control, typically with material added layer by layer.

[0063] As used herein, the term “fossil fuel” means any carbon compound or hydrocarbon-containing material, including but not limited to motor gasoline, diesel fuel, gasohol, kerosene, propane, and any combination of the aforementioned materials, as well as coal, petroleum, oil, and natural gas, and fuels derived from the physical separation, conversion and / or recombination of these materials.

[0064] As used herein, the term “coolant” refers to a fluid transported through and / or around components to control their temperature. The coolant may, in some cases, cool the components by removing heat from them, or in other cases, heat the components by transferring heat contained within them. Coolants may be inorganic additive technology (IAT) coolants (such as ethylene glycol (i.e., antifreeze) in the form of conventional low-silicate coolants, fully formulated coolants, or long-life coolants), organic acid technology (OAT) coolants, and / or hybrid organic acid technology (HOAT) coolants. Furthermore, the coolant may be a heat-transferring medium, such as water, refrigerant, betaine, polyalkylene glycol, propylene glycol, oil, liquefied gas, nanofluids, and similar. [Modes for carrying out the invention]

[0065] It should be understood that aspects of the present invention are described herein with reference to the figures illustrating exemplary embodiments. The exemplary embodiments herein are not necessarily intended to illustrate all embodiments of the present invention, but rather to illustrate a small number of exemplary embodiments. Therefore, aspects of the present invention are not intended to be interpreted narrowly in view of the exemplary embodiments. Furthermore, although the present invention is described in relation to its application in an internal combustion engine for a motor vehicle, it should be understood that the system can be implemented in any engine-driven configuration that can be powered by ammonia and / or hydrogen fuel.

[0066] Figure 1 is a perspective internal view of a heat exchange catalyst unit that functions as a heat exchanger and a catalytic converter for ammonia cracking, utilizing a TPMS structure, according to one embodiment of the present invention. The heat exchange catalyst unit 100 is made of metal and, in one embodiment, includes a gaseous ammonia inlet 102, a hydrogen outlet 104, a heated exhaust gas inlet 106, and an exhaust gas outlet 108. In one embodiment, the heat exchange catalyst unit 100 is made of a nickel alloy. In a preferred embodiment, the heat exchange catalyst unit 100 is made of Inconel® 625.

[0067] In one embodiment, the gaseous ammonia inlet 102, hydrogen outlet 104, heated exhaust gas inlet 106, and exhaust gas outlet 108 can be made from the same metallic material as the heat exchange catalyst unit 100. In another embodiment, the gaseous ammonia inlet 102, hydrogen outlet 104, heated exhaust gas inlet 106, and exhaust gas outlet 108 can be made from stainless steel, silver, bronze, and equivalent alloys.

[0068] The matrix 110 is located between the inlets 102 and 106 and the outlets 104 and 108. The matrix 110 is formed from widthwise surfaces 112 and lengthwise surfaces 114 that extend substantially perpendicular to each other. The surfaces 112 and 114 of the matrix 110 create passages that allow gaseous ammonia and heated exhaust gas to flow; these passages are indicated by the ammonia channel 116 and the heated exhaust gas channel 118. Gaseous ammonia is supplied to the heat exchange catalyst unit 100 via the inlet 102, while heated exhaust gas is supplied simultaneously to the inlet 106. Gaseous ammonia traverses the matrix 110 via the ammonia channel 116, and heated exhaust gas traverses the matrix via the heated exhaust gas channel 118. The ammonia channel 116 and the heated exhaust gas channel 118 are oriented substantially perpendicular to each other, so that gaseous ammonia traverses the matrix 110 substantially perpendicular to the heated exhaust gas.

[0069] In one embodiment, surfaces 112 and 114 may have a thickness of 1 to 2 millimeters, and each of surfaces 112 and 114 may have the same thickness. In another embodiment, surfaces 112 and 114 may each have different thicknesses. In yet another embodiment, surfaces 112 and 114 may vary in thickness as they traverse the matrix 110. For example, surfaces 112 and 114 may not have a uniform thickness across the entire width of the matrix 110, and may have thicker or narrower portions at various locations.

[0070] As shown in Figure 1, the matrix 110 physically separates the gases passing through channels 116 and 118, thereby providing an exceptionally large surface area across the entire matrix 110 for the heated exhaust gas to exchange its heat with gaseous ammonia. In one embodiment, surfaces 112 and 114 of the matrix 110 are coated with a catalyst that facilitates the cracking of ammonia into constituent hydrogen and nitrogen components (hereinafter collectively referred to as the "hydrogen gas mixture"). In this embodiment, surfaces 112 and 114 of the matrix 110 are coated with the catalyst using a wash coating or deposition technique that binds or deposits the catalyst onto surfaces 112 and 114.

[0071] In another embodiment, a catalyst in the form of a separate catalytic medium is deposited in the passages that form the ammonia channel 116 and the heated exhaust gas channel 118. The separate catalytic medium can be porous, thereby allowing gaseous ammonia and exhaust gas to pass through the catalyst as they flow through the matrix 110, respectively.

[0072] In yet another embodiment, the surfaces 112 and 114 of the matrix 110 can be coated with the catalyst described herein, and additional separate catalytic media can be deposited in the passages that form the ammonia channels 116 and the heated exhaust gas channels 118.

[0073] In one embodiment, the matrix 110 is made of metal and is constructed from a nickel alloy. In a preferred embodiment, the matrix 110 is made from Inconel® 625. The heat exchange catalyst unit 100 and the matrix 110 may be constructed from the same metallic material. In another embodiment, the heat exchange catalyst unit 100 and the matrix 110 may be constructed from different metallic materials.

[0074] The materials selected for the heat exchange catalyst unit 100 and matrix 110 must have the ability to withstand the corrosive environment resulting from high-temperature heated exhaust gases and the heated hydrogen gas produced from ammonia cracking.

[0075] In a preferred embodiment, the matrix 110 is in the form of a triple periodic minimal surface (TPMS), and the matrix 110 is three-dimensionally (3D) printed using powder metal. The 3D printing process is an additive manufacturing process that uses laser sintering to selectively fuse powder metal particles together to form a TPMS structure in a layer-by-layer strategy. The TPMS structure of the matrix 110 provides a relatively large surface area containing cells that can be confined within the dimensions and shape of the heat exchange catalyst unit 100.

[0076] TPMS structures can be diverse crystalline structures with various patterns and profiles. In the embodiment shown in Figure 1, the TPMS is a gyroid structure. The structure can be, but is not limited to, gyroid, diamond, orthogonal-pore, and split pea forms, among many others. Each of these forms has a different surface area. For example, in the embodiment shown in Figure 1, the heat exchange catalyst unit 100 has dimensions of approximately 10 × 10 × 4 inches (25.4 × 25.4 × 10.16 cm). With respect to a matrix 110 that fits within these dimensions, Table 1 provides approximate surface area values ​​for various TPMS structures that can be used. Table 1 [Table 1]

[0077] However, it should be noted that the values ​​in Table 1 are merely illustrative examples and are not intended to be limiting in any way. The individual cell sizes of the TPMS can be modified to increase or decrease the surface area of ​​the matrix 110. For example, within the same volume of heat exchange catalyst unit 100, the overall surface area of ​​the matrix 110 can be increased by increasing the individual cell sizes, and conversely, the overall surface area of ​​the matrix 110 can be decreased by decreasing the individual cell sizes.

[0078] The TPMS structure is ideal for matrix 110 because it allows heat to be distributed across all surfaces of matrix 100, thereby facilitating the chemical reactions required for the ammonia cracking process. As the surface area increases, the configuration of channels 116 and 118 becomes narrower relative to each other, and as the surface area of ​​matrix 110 increases, inherent challenges arise when cleaning its surface after printing. However, increasing the cell size of matrix 110 reduces the surface area, thereby decreasing the throughput efficiency of the heat exchange catalyst unit 100. The surface area of ​​matrix 110 may depend on the power requirements of the motor vehicle and its engine.

[0079] In one embodiment, the heat exchange catalyst unit 100 is sized and sized to accommodate a matrix 110 having sufficient surface area to facilitate the cracking process, while still having a form factor suitable for placement within a motor vehicle. The dimensions of the heat exchange catalyst unit 100 can vary, and can range from 5 to 30 inches in width, 5 to 30 inches in length, and 0.5 to 12 inches in height.

[0080] In one embodiment, the heat exchange catalyst unit 100 has a substantially square shape that accommodates a square-shaped matrix 110, as shown in Figure 1, which is merely an illustrative example and is not intended to limit the unit in any way. In other embodiments, the heat exchange catalyst unit 100 can be any polygonal shape, such as ellipse, oblong, triangular, square, kite, trapezoid, parallelogram, rhombus, and the like, and various 3D shapes, such as cube, cuboid, sphere, cone, and the like.

[0081] In one embodiment, since the exhaust gas flow rate may be several orders of magnitude higher than the ammonia flow rate, the ammonia inlet 102 has a smaller diameter than the heated exhaust gas inlet 106. Similar to the dimensions of the heat exchange catalyst unit 100, the diameters, shapes, and sizes of the inlets 102, 106 and outlets 104, 108 can be varied based on the power requirements of the motor vehicle and its engine.

[0082] Figure 2 is a perspective internal view of a heat exchange catalyst unit 100 utilizing a TPMS structure according to one embodiment of the present invention, showing the flow of heated exhaust gas and gaseous ammonia through the matrix. During operation, gaseous ammonia 200 is supplied to the inlet 102 and flows through the ammonia channel 116, and heated exhaust gas 202 is simultaneously supplied to the inlet 106 and flows through the heated gas channel 118. The heated exhaust gas 202 heats the catalyst, resulting in cracking of the gaseous ammonia 200 and the formation of a hydrogen gas mixture 204. The hydrogen gas mixture 204 exits the heat exchange catalyst unit 100 through the outlet 104 and is supplied to the downstream injection system of the engine, while the residual exhaust gas 206 exits the heat exchange catalyst unit through the outlet 108.

[0083] Figure 3 is a perspective view of a matrix 110 having a gyroid TPMS structure, Figure 4 is a perspective view of a matrix 110 having an orthogonal hole TPMS structure, and Figure 5 is a perspective view of a matrix 110 having a split-P TPMS structure, all of which are according to one embodiment of the present invention. However, it should be noted that the TPMS structures shown in Figures 1 to 5 are merely illustrative examples and are not intended to limit the present invention in any way.

[0084] Figure 6 is a top perspective view of a heat exchange catalyst unit 100 utilizing a TPMS structure according to one embodiment of the present invention. In one embodiment, the heat exchange catalyst unit 100 can be manufactured by welding inlets 102, 106 and outlets 104, 108 to a housing 600. In one embodiment, the housing 600 may include a cover (not shown in Figure 6) that can be removed for maintenance or replacement of the matrix 110. In another embodiment, the inlets 102, 106 and / or outlets 104, 108 can be detachably mounted to the housing 600, so that various inlets and outlets with various dimensions, sizes, and flow characteristics can be used modularly with the housing 600.

[0085] Figure 7 is a front cross-sectional view of a cylindrical heat exchange catalyst unit 700 utilizing a TPMS structure according to one embodiment of the present invention. Similar to the heat exchange catalyst unit 100 shown in Figure 1, the cylindrical heat exchange catalyst unit 700 is made of metal and nickel alloy, and in a preferred embodiment, the cylindrical heat exchange catalyst unit 700 is made of Inconel® 625.

[0086] In one embodiment, the cylindrical heat exchange catalyst unit 700 includes an ammonia inlet 702, a hydrogen outlet 704, a heated exhaust gas inlet 706, and an exhaust gas outlet 708. Positioned between the inlets 702, 706 and the outlets 704, 708 is a matrix 710. The matrix 710 is formed from widthwise surfaces 712 and lengthwise surfaces 714 that extend substantially perpendicular to each other. The surfaces 712, 714 of the matrix 710 create passages that allow gaseous ammonia and heated exhaust gas to flow; these passages are indicated by an ammonia channel 716 and a heated exhaust gas channel 718.

[0087] Gaseous ammonia is supplied to the cylindrical heat exchange catalyst unit 700 via inlet 702, while heated exhaust gas is simultaneously supplied to inlet 706. The gaseous ammonia traverses the matrix 710 in the axial direction, and the heated exhaust gas traverses the matrix laterally.

[0088] As shown in Figure 7, the matrix 710 physically separates the gases passing through channels 716 and 718, thereby providing an exceptionally large surface area across the entire matrix 710 for the heated exhaust gas to exchange heat with gaseous ammonia. In one embodiment, surfaces 712 and 714 of the matrix 710 are coated with a catalyst that facilitates the cracking of ammonia into a hydrogen gas mixture. In this embodiment, surfaces 712 and 714 of the matrix 710 are coated with the catalyst using a wash coating or deposition technique that binds or deposits the catalyst onto surfaces 712 and 714.

[0089] In another embodiment, a catalyst in the form of a separate catalytic medium is deposited in the passages that form the ammonia channel 716 and the heated exhaust gas channel 718.

[0090] In yet another embodiment, the surfaces 712 and 714 of the matrix 710 can be coated with the catalyst described herein, and additional separate catalytic media can be deposited in the passages that form the ammonia channel 716 and the heated exhaust gas channel 718.

[0091] Figure 8 is a front cross-sectional view of a cylindrical heat exchange catalyst unit 700 utilizing a TPMS structure according to one embodiment of the present invention, showing the flow of heated exhaust gas and gaseous ammonia through the matrix. During operation, gaseous ammonia 200 is supplied to the inlet 702 and flows through the ammonia channel 716, while heated exhaust gas 202 is simultaneously supplied to the inlet 706 and flows through the heated gas channel 718. The heated exhaust gas 202 heats the catalyst, resulting in cracking of the ammonia 200 and the formation of a hydrogen gas mixture 204. The hydrogen gas mixture 204 exits the heat exchange catalyst unit 700 through the outlet 704 and is supplied to the downstream injection system of the engine, while the residual exhaust gas 206 exits the heat exchange catalyst unit through the outlet 708.

[0092] Therefore, since the resulting hydrogen and nitrogen components 204 are used as combustion fuel by the present invention, either alone or in combination with ammonia as a co-fuel, no fossil fuels are ever supplied to the engine's injection system as a primary fuel, accelerator, co-fuel, additive, auxiliary fuel, or otherwise. The absence of carbon in the combustion fuel means that no carbon dioxide is produced by the internal combustion engine of the present invention, and thus completely eliminates the major greenhouse gas emissions of conventional gasoline or petroleum engines.

[0093] Figure 9 is a side cross-sectional view of a cylindrical heat exchange catalyst unit 700 utilizing a TPMS structure according to one embodiment of the present invention, showing the flow of heated exhaust gas and gaseous ammonia through the matrix. As shown in Figure 9, surfaces 712 and 714 of the matrix 710 create ammonia channels 716 and heated exhaust gas channels 718. The cylindrical design can provide efficiency for mass production considering its rounded sections, fewer welded seams / joints compared to square and rectangular designs, and lower susceptibility to thermal stress.

[0094] It should be noted that the cylindrical shape of the cylindrical heat exchange catalyst unit 700 is merely an illustrative example and is not intended to limit it in any way. In other embodiments, the heat exchange catalyst unit 700 may be any polygonal shape, such as ellipse, oblong, triangular, square, kite, trapezoid, parallelogram, rhombic, and the like, and various 3D shapes, such as cube, cuboid, sphere, cone, and the like.

[0095] Figure 10 is a perspective view of a heat exchange catalyst unit 1000, according to one embodiment of the present invention, which utilizes a tube bundle structure and functions as a heat exchanger and a catalytic converter for ammonia cracking. The heat exchange catalyst unit 1000 is made of metal and, in one embodiment, includes a side wall 1002 containing a gaseous ammonia inlet 1004. In one embodiment, the inlet side wall 1002 may include an additional port 1006 that can be used for various functions. For example, port 1006 may function as an inlet or may be coupled to equipment for temperature, throughput, and / or pressure sensing.

[0096] The heat exchange catalyst unit 1000 further includes a heated gas inlet 1008. In one embodiment, the heated exhaust gas inlet 1008 includes a partition 1010 that evenly distributes the heated exhaust gas from the engine onto an internal tube bundle structure housed within the heat exchange catalyst unit 1000, which is described in more detail with reference to Figure 11. In one embodiment, the partition 1010 may have a grid or lattice structure.

[0097] The heat exchange catalyst unit 1000 includes an exhaust gas outlet 1012 positioned on the opposite side of the heated gas inlet 1008.

[0098] Figure 11 is a front cross-sectional view of a heat exchange catalyst unit 1000 utilizing a tube bundle structure according to one embodiment of the present invention. In one embodiment, the tube bundle structure 1100 is located inside the heat exchange catalyst unit 1000. The tube bundle structure 1100 consists of individual tubes 1102 that extend perpendicularly from the side wall 1002 along the width of the heat exchange catalyst unit 1000 to the inlet 1008 and outlet 1012.

[0099] In one embodiment, the tube bundle structure 1100 includes rows and / or columns of tubes 1102 arranged in an offset manner, so that each adjacent row and / or column includes a tube offset from its adjacent tube. This pattern maximizes the surface area in contact with the heated exhaust gas as it traverses the tube bundle structure 1100, thereby maximizing the amount of catalyst heated to facilitate the cracking process.

[0100] In one embodiment, the heat exchange catalyst unit 1000 includes at least one support structure 1104 that facilitates the 3D printing process and further provides stability against thermal stress during the operation of the heat exchange catalyst unit 1000.

[0101] Gaseous ammonia is supplied to the heat exchange catalyst unit 1000 via inlet 1004, while heated exhaust gas is simultaneously supplied to inlet 1008. The gaseous ammonia traverses the lateral space between the tubes 1102, and the heated exhaust gas traverses the axial space inside the tubes 1102.

[0102] In one embodiment, the space between the tubes 1102 is filled with a catalyst in the form of a separate catalytic medium. In another embodiment, the tubes 1102 themselves are hollow and are also filled with a separate catalytic medium.

[0103] In yet another embodiment, the outer and / or inner surfaces of the tube 1102 are also coated with catalyst using a wash coating or deposition technique that binds or deposits the catalyst onto the surface.

[0104] Figure 12 is a side cross-sectional view of a heat exchange catalyst unit 1000 utilizing a tube bundle structure 1100 according to one embodiment of the present invention. In one embodiment, the heat exchange catalyst unit 1000 includes a side wall 1200 positioned opposite the side wall 1002. The side wall 1200 includes a hydrogen outlet 1202 and may include an additional port 1204 which may be used for various functions. For example, port 1204 may function as an outlet or may be coupled to equipment for temperature, throughput, and / or pressure sensing.

[0105] During operation, gaseous ammonia is supplied to inlet 1004, and heated exhaust gas is simultaneously supplied to inlet 1008. The heated exhaust gas heats the catalyst, resulting in cracking of the gaseous ammonia and the formation of a hydrogen gas mixture. The resulting hydrogen gas mixture exits the heat exchange catalyst unit 1000 via outlet 1202 and is supplied to the engine downstream.

[0106] In one embodiment, the heat exchange catalyst unit 1000 is made from a nickel alloy. In a preferred embodiment, the heat exchange catalyst unit 1000 is made from Inconel® 625.

[0107] In one embodiment, the side walls 1002, 1200, the gaseous ammonia inlet 1004, the hydrogen outlet 1202, the heated exhaust gas inlet 1008, the partition 1010, the exhaust gas outlet 1012, and the support structure 1104 can be made from the same metallic material as the heat exchange catalyst unit 1000. In another embodiment, the side walls 1002, 1200, the gaseous ammonia inlet 1004, the partition 1010, the hydrogen outlet 1202, the heated exhaust gas inlet 1008, and the exhaust gas outlet 1012 can be made from stainless steel, silver, bronze, and equivalent alloys.

[0108] Figure 13 is a front cross-sectional view of a two-pass heat exchange catalyst unit 1300 utilizing a tube bundle structure 1100 according to one embodiment of the present invention. In this embodiment, the support structure 1302 includes a fascia that receives the side walls (not shown in Figure 13). The support structure 1302 includes a partition 1304 that physically separates the tube bundle structure 1100 into a left portion 1306 and a right portion 1308. The partition 1304 extends along the width of the two-pass heat exchange catalyst unit 1300 between the two side walls. In this embodiment, the gaseous ammonia inlet is located in the side wall covering the left portion 1306, and the hydrogen outlet is located in the side wall covering the right portion 1308.

[0109] During operation, gaseous ammonia is supplied to the gaseous ammonia inlet, and heated exhaust gas is simultaneously supplied to the inlet 1008. As the ammonia crosses the left portion 1306 of the tube bundle structure 1100, the heated exhaust gas heats the catalyst, resulting in the cracking of the ammonia into the hydrogen gas mixture. The remaining ammonia returns across the right portion 1308 of the tube bundle structure 1100, undergoing further cracking, thereby providing a two-pass cracking process. The resulting hydrogen gas mixture exits the two-pass heat exchange catalyst unit 1300 through the hydrogen outlet and is supplied to the downstream engine.

[0110] Figure 14 is a block diagram of an onboard ammonia cracking system for an internal combustion engine according to one embodiment of the present invention. The onboard ammonia cracking system 1400 provides a mechanism for generating hydrogen from ammonia, thereby eliminating the need for the motor vehicle to maintain a separate hydrogen tank.

[0111] Referring to Figure 14, the liquid ammonia tank 1402 is mounted on a motor vehicle or engine, and in one embodiment, the liquid ammonia tank 1402 can be coupled to a pump 1404. In one embodiment, the tank 1402 is refillable and / or replaceable. The pump 1404 can be coupled to a port of the tank 1402 to facilitate the delivery of ammonia from the tank 1402. For example, in a low-temperature environment where the temperature is about 0°C or lower, the vapor pressure of ammonia is not sufficient to push itself out of the tank 1402. Therefore, the pump 1404 is required to draw or push the ammonia out of the tank 1402.

[0112] In one embodiment, multiple liquid ammonia tanks can be mounted on a motor vehicle or engine, where each ammonia tank can supply ammonia to a separate onboard cracking system as described herein with respect to Figures 20-23.

[0113] In another embodiment, an electric heater (not shown in Figure 14) is coupled to the tank 1402, either inside the tank 1402 or on the outer surface of the tank 1402, and can heat the liquid ammonia contained in the tank 1402 to a temperature at which it vaporizes into a gaseous state.

[0114] In one embodiment, a pressure regulator 1406 is coupled to the outlet of a tank 1402 and functions to control the volume and / or flow rate of ammonia drawn out of the tank 1402 by a pump 1404. The pressure regulator 1406 monitors the pressure of liquid ammonia in the tank 1402. When the pressure drops to a threshold pressure value at which the liquid ammonia can vaporize into a gaseous state, the pressure regulator 1406 opens and supplies gaseous ammonia downstream. Any residual liquid ammonia that passes through the pressure regulator 1406 is also supplied to the injection system 1408 (for example, via a T-fitting on the supply line).

[0115] In one embodiment, a temperature control valve 1410 receives a temperature feedback signal 1412 during a cold start of the engine, which includes a temperature reading from the electrocatalytic unit 1420. The temperature feedback signal 1412 may be generated by a temperature sensor coupled to the electrocatalytic unit 1420. When the electrocatalytic unit 1420 reaches a threshold temperature suitable for carrying out the ammonia cracking process (i.e., the temperature reading is equal to or greater than the threshold temperature), the temperature control valve 1410 opens, allowing gaseous ammonia to pass through the heat exchange catalyst unit 1418 and move downstream to the electrocatalytic unit 1420, where it is heated using power supplied from the vehicle power system 1422.

[0116] If the electrocatalytic unit 1420 has not reached the threshold temperature, the temperature control valve 1410 continues to monitor the temperature feedback signal 1412 to prevent the downstream movement of gaseous ammonia. Cold start operation is described in more detail herein.

[0117] In one embodiment, the temperature of the heated exhaust gas entering the heat exchange catalyst unit 1418 is determined based on the current drawn into the electrocatalyst unit 1420, where the current drawn is an indicator of how effective the heat exchange catalyst unit 1418 is in cracking gaseous ammonia.

[0118] For example, if there is hydrogen and nitrogen passing from the heat exchange catalyst unit 1418 to the electrocatalyst unit 1420, the electrocatalyst unit 1420 does not perform the ammonia cracking process and therefore draws in a minimum or no current.

[0119] However, when gaseous ammonia passes from the heat exchange catalyst unit 1418 to the electrocatalyst unit 1420, an ammonia cracking process occurs, drawing an electric current to heat the heating element located within the electrocatalyst unit 1420.

[0120] However, during normal or high-load engine operating conditions (i.e., when not under cold start or low-load operating conditions), the onboard ammonia cracking system 1400 does not utilize the electrocatalytic unit 1420 to perform the ammonia cracking process, as the heat exchange catalytic unit 1418 is heated to a threshold temperature by the heated exhaust gas from the engine, and this unit performs the ammonia cracking process.

[0121] The heat exchange catalyst unit 1418 referenced in Figure 14 may be any of the embodiments described herein, namely the heat exchange catalyst unit 100 utilizing a TPMS structure, the cylindrical heat exchange catalyst unit 700 utilizing a TPMS structure, the heat exchange catalyst unit 1000 utilizing a tube bundle structure, the two-pass heat exchange catalyst unit 1300 utilizing a tube bundle structure, or the plate heat exchange unit described in the jointly owned U.S. Nonprovisional Patent Application No. 18 / 241,321 filed on September 1, 2023, entitled "SYSTEMS AND METHODS FOR THE ON-BOARD CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA USING A PLATE HEAT EXCHANGE CATALYST UNIT," the disclosure of which is incorporated herein by reference in its entirety.

[0122] The pressure control valve 1414 is located in series with the temperature control valve 1410 and controls the amount of gaseous ammonia supplied to the heat exchange catalyst unit 1418.

[0123] In one embodiment, the pressure control valve 1414 receives a pressure feedback signal 1416 from the heat exchange catalyst unit 1418. For example, the heat exchange catalyst unit 1418 can be coupled to a pressure transducer or similar device (not shown in Figure 14) that generates the pressure feedback signal 1416.

[0124] In one embodiment, to facilitate a cold start of the onboard ammonia cracking system 1400 when the exhaust gas from the engine is not at a suitable threshold temperature for carrying out the ammonia cracking process, an electrocatalytic unit 1420 is used to heat the catalyst so that gaseous ammonia can be cracked, and the resulting hydrogen is supplied to a downstream injection system for the engine. The engine can then burn the hydrogen to power itself, thereby supplying heated exhaust gas to the onboard ammonia cracking system 1400.

[0125] In one embodiment, the electrocatalytic unit 1420 is coupled to a vehicle power system 1422, such as a conventional vehicle battery. In another embodiment, the electrocatalytic unit 1420 can be heated via an auxiliary heat source / power source, such as a renewable energy source, a portable battery source, an onboard electric battery pack, and / or a rechargeable battery.

[0126] In addition to facilitating the cold start of the onboard ammonia cracking system 1400, the electrocatalytic unit 1420 is used to replenish the heat exchange catalytic unit 1418 during low-load engine operating conditions, such as when the vehicle is stopped, moving at a low speed, or idling. For example, during low-load operating conditions, the engine exhaust gas temperature can drop significantly. The reduced temperature of the exhaust gas flowing into the heat exchange catalytic unit 1418 during such low-load operating conditions may not be sufficient for the catalyst to crack ammonia. In one embodiment, depending on the specific catalyst used, the exhaust gas temperature needs to be at least 400°C to 700°C to carry out the ammonia cracking process, and in one preferred embodiment, the exhaust gas temperature is at least 600°C to carry out the ammonia cracking process.

[0127] In this scenario, cold gaseous ammonia passes through the heat exchange catalyst unit 1418 and is supplied downstream to the electrocatalyst unit 1420, which is heated using electricity supplied from the vehicle power system 1422. When the electrocatalyst unit 1420 is heated to a threshold temperature suitable for the ammonia cracking process, the temperature control valve 1410 opens, allowing gaseous ammonia to be supplied to the heat exchange catalyst unit 1418 and finally to the electrocatalyst unit 1420. The electrocatalyst unit 1420 then carries out the ammonia cracking process, and the resulting hydrogen is supplied to the downstream injection system for the engine.

[0128] When the exhaust gas flowing into the heat exchange catalyst unit 1418 reaches a threshold temperature suitable for the ammonia cracking process, such as under normal or high-load engine operating conditions, the ammonia cracking process occurs within the heat exchange catalyst unit 1418. The resulting hydrogen and nitrogen pass downstream through the electrocatalytic catalyst unit 1420, further downstream to the gas-liquid or gas-gas heat exchange unit 1428, and then to the engine's injection system 1430. In one embodiment, the gas-liquid or gas-gas heat exchange unit 1428 may utilize engine coolant and / or engine radiator or be injected with ammonia gas or liquid to accelerate the heat exchange process.

[0129] In one embodiment, the pressure regulator 1406 may be controlled using an electric servo motor to provide a stable flow of gaseous ammonia from the tank 1402. In another embodiment, a pulse width modulation injection valve may be used. The servo motor and / or pulse generator may be controlled using an electronic controller such as an industrial PID controller (not shown in Figure 14).

[0130] In one embodiment, the electronic controller may be coupled to various components of the onboard ammonia cracking system 1400 and receive inputs from a pressure regulator 1406, a temperature control valve 1410, a pressure control valve 1414, and from sensors such as temperature sensors and pressure transducers that may be coupled to a heat exchange catalyst unit 1418 and / or an electrocatalytic unit 1420.

[0131] In another embodiment, the electronic controller can be integrated into the hardware and software together with the vehicle's electronic control unit (ECU). In this embodiment, the flow rate of hydrogen supplied to the engine's injection system may be measured and reported back to the ECU, which acts as a mechanism for controlling the injection strategy.

[0132] Figures 15-17 are various perspective views of the onboard ammonia cracking system 1400 for the internal combustion engine described in Figure 14, according to one embodiment of the present invention.

[0133] Figure 18 is a perspective view of an electrocatalytic unit. In one embodiment, the electrocatalytic unit 1800 includes a housing 1802 surrounding a ceramic tube 1900 (shown in Figure 19) according to one embodiment of the present invention. In one embodiment, the housing 1802 is a metal housing.

[0134] In one embodiment, the electrocatalytic unit 1800 includes a gaseous ammonia inlet 1804 and a hydrogen outlet 1806 located at the opposite end of the electrocatalytic unit 1800. The electrocatalytic unit further includes power feedthroughs 1808, 1810 for a heating element 1904 (shown in Figure 19). In one embodiment, the electrocatalytic unit 1800 may include radial fixtures 1812, 1814 which can be used for a variety of functions. For example, the radial fixtures 1812, 1814 may function as inlets and outlets, or be coupled to devices for temperature, throughput and / or pressure sensing. In one embodiment, the radial fixture 1812 may each include or be coupled to thermocouples, and the radial fixture 1814 may include or be coupled to a pressure transducer.

[0135] Figure 19 is a cross-sectional view of the electrocatalyst unit 1800. In one embodiment, the ceramic tube 1900 houses the catalyst according to one embodiment of the present invention. The ceramic tube 1900 functions as an insulator and allows heat to be focused and reflected toward the catalyst, thereby heating the catalyst.

[0136] In one embodiment, a first screen 1901 and a second screen 1902 are provided at both ends of a ceramic tube 1900. Screens 1901 and 1902 can be made from wire, wire mesh, or another metal mesh or matrix structure. In one embodiment, screens 1901 and 1902 can be made from a nickel alloy that is resistant to heated hydrogen gas generated from ammonia cracking and resistant to gaseous ammonia itself.

[0137] In one embodiment, a heating element 1904 is also provided inside the ceramic tube 1900. Current passes through the heating element 1904, heating it to a threshold temperature suitable for the ammonia cracking process. Since nickel maintains a fairly constant resistance at high temperatures, in contrast to steel which exhibits low resistance at high temperatures, in one embodiment, the heating element 1904 and screens 1901, 1902 are made from a nickel alloy or other material resistant to hydrogen and ammonia. Furthermore, the nickel alloy may have higher corrosion resistance during high-temperature exposure to ammonia and hydrogen (this may be achieved, for example, within the electrocatalytic unit 1800, such as at temperatures above 600°C).

[0138] In one preferred embodiment, the heating element 1904 and the screens 1901, 1902 are made from Inconel® 625. In one embodiment, the heating element 1904 and the screens 1901, 1902 can be made from the same material. Alternatively, the heating element 1904 and the screens 1901, 1902 can be made from different materials.

[0139] In one embodiment, the heating element 1904 may be an air process heater, a cartridge heater, a tube heater, a band heater, a strip heater, an etched foil heater (or thin film heater), a ceramic heater, a ceramic fiber heater, a resistive wire, and the like.

[0140] In one embodiment, each end of the heating element 1904 is in contact with power feedthroughs 1808 and 1810. The power feedthroughs 1808 and 1810 energize the heating element 1904 or provide electricity to heat it.

[0141] In one embodiment, the heating element 1904 is regulated via an electronic controller coupled to power feedthroughs 1808, 1810 by utilizing readings from a thermocouple coupled to a radial mounting fixture 1812, thereby maintaining a threshold temperature suitable for carrying out the ammonia cracking process. The threshold temperature can be in the range of 400°C to 700°C, and in one preferred embodiment, the threshold temperature is at least 600°C.

[0142] In one embodiment, an electronic controller can be used to control an electric expansion valve (not shown in Figure 19) coupled to the inlet 1804 by utilizing readings from a pressure transducer coupled to a radial fixture 1814 and / or a thermocouple coupled to a radial fixture 1812. When the gaseous ammonia received from the heat exchange catalyst unit by the electrocatalyst unit 1800 reaches a threshold temperature, the electric expansion valve is used to maintain the vapor pressure of the gaseous ammonia. At these threshold temperatures and pressure values, the electric expansion valve opens, allowing ammonia to enter the ceramic tube 1900.

[0143] In one embodiment, a catalyst, such as a separate catalytic medium, is deposited inside a ceramic tube. Gaseous ammonia undergoes a chemical reaction with the catalyst placed inside the ceramic tube 1900, and the resulting hydrogen gas mixture exits the electrocatalytic unit 1800 through outlet 1806 and is supplied to the engine's downstream injection system.

[0144] In another embodiment, the heating element 1904 is coated with a catalyst that facilitates the ammonia cracking process, and the separate catalyst is not provided inside the ceramic tube 1900. In this embodiment, the catalyst is coated onto the heating element 1904 using a wash coating or deposition technique that binds or deposits the catalyst onto the surface of the heating element 1904.

[0145] In one embodiment, the heating element 1904 is a strip heater. The heating element 1904 can be coated with a catalyst on all surfaces, or alternatively, a catalyst sleeve can be arranged to cover the strip heating element 1904. In one embodiment, the strip heating element 1904 has a relatively low heat transfer efficiency, thereby allowing a high surface (or boundary layer) temperature of the catalyst coating the outside of the strip heating element 1904 to be maintained.

[0146] In another embodiment, the heating element 1904 is a spiral heater, a coil heater, or an air process heater, where the inner wall (including an integral heating element) is coated with a catalyst.

[0147] In yet another embodiment, the catalyst is coated on the inner wall of the ceramic tube 1900. In this embodiment, the catalyst is coated on the inner wall of the ceramic tube 1900 using a wash coating or deposition technique that bonds or adheres the catalyst to the wall surface.

[0148] Figure 20 is a perspective view of a dual onboard ammonia cracking system mounted in the internal combustion engine compartment of a motor vehicle according to one embodiment of the present invention. In one embodiment, the dual onboard cracking systems 1400a,b described herein in relation to Figure 14 are mounted in the engine compartment 2000 and are used to supply the hydrogen gas mixture obtained as a result of cracking, or as co-fuel together with ammonia, to the injection system of an 8-cylinder piston engine 2002 (hereinafter, "V8 engine").

[0149] In one embodiment, the engine 2002 includes left and right banks of four cylinders each sharing a common crankshaft, and an intake manifold 2004 including left and right bank hydrogen fuel rails 2006a, b and left and right bank ammonia fuel rails 2008a, b. In the embodiment, a left bank onboard cracking system 1400a supplies a hydrogen gas mixture to the left bank hydrogen fuel rail 2006a, and a right bank onboard cracking system 1400b supplies a hydrogen gas mixture to the right bank hydrogen fuel rail 2006b.

[0150] In one embodiment, the ammonia fuel rails 2008a and 2008b are mounted on top of the intake manifold 2004, above the mounting positions of the respective hydrogen fuel rails 2006a and 2006b. In another embodiment, the mounting positions of the ammonia fuel rails 2008a and 2008b and the hydrogen fuel rails 2006a and 2006b can be reversed, so that the hydrogen fuel rails 2006a and 2006b are mounted on top of the intake manifold 2004, above the mounting positions of the ammonia fuel rails 2008a and 2008b.

[0151] The engine 2002 further includes left and right bank exhaust manifolds 2010a and 2010b. Each exhaust manifold 2010a and 2010b is coupled to its respective left and right bank heat exchange catalytic converter units 1418a and 2018b. The exhaust manifolds 2010a and 2010b collect exhaust gases from multiple cylinders in the engine 2002 and allow the exhaust gases to flow to their respective heat exchange catalytic converter units 1418a and 2018b. For example, the left bank exhaust manifold 2010a collects exhaust gases generated from the left bank cylinders and directs these exhaust gases to the left bank heat exchange catalytic converter unit 1418a.

[0152] In one embodiment, the outlet of the left bank heat exchange catalyst unit 1418a is connected to the exhaust pipe 2014 via a conduit 2012. In another embodiment, each heat exchange catalyst unit 1418a,b has an outlet connected to an independent exhaust pipe, and the outlets of the two heat exchange catalyst units 1481a,b are not fluidly connected via a conduit.

[0153] In one embodiment, each onboard cracking system 1400a,b includes an expansion valve 2016 which is fluidly coupled to the ammonia inlet of a plate heat exchange unit 2018 via a supply line 2020.

[0154] The ammonia outlet of the plate heat exchange unit 2018 is fluidically coupled to the ammonia inlet of the electrocatalyst unit 1420 via supply line 2022, and to the ammonia inlet of each heat exchange catalyst unit 1418 via supply line 2024.

[0155] The hydrogen inlet of the electrocatalytic unit 1420 is fluidically coupled to the hydrogen outlet of each heat exchange catalyst unit 1418 via the supply line 2026.

[0156] The hydrogen outlet of the electrocatalytic unit 1420 is fluidically coupled to the hydrogen inlet of the plate heat exchange unit 2018 via the supply line 2028.

[0157] The hydrogen outlet of the plate heat exchange unit 2018 is fluidically coupled to each hydrogen fuel rail 2006 via the supply line 2030.

[0158] The use of the plate heat exchange unit 2018 is not intended to be limited in any way, and various other types of heat exchange units may be used, as described herein, for preheating low-temperature gaseous ammonia from ammonia tank 1402 and for cooling a high-temperature hydrogen gas mixture from electrocatalytic unit 1420.

[0159] In a preferred embodiment, there is a single ammonia tank 1402 that supplies ammonia to both onboard cracking systems 1400a,b. However, in another embodiment, each onboard cracking system 1400a,b may have a separate, dedicated ammonia tank from which it receives ammonia. In this embodiment, the number of ammonia tanks directly correlates to the number of onboard cracking systems utilized within the engine compartment.

[0160] In one embodiment, each onboard cracking system 1400a, b further includes an expansion valve 2032 which is fluidically coupled to the ammonia inlet of the evaporator 2034 via a supply line 2036. The ammonia outlet of the evaporator 2034 is fluidically coupled to the respective ammonia fuel rail 2008 via a supply line 2038. The coolant outlets are fluidly coupled to radiators (not shown in Figure 20) via the respective supply lines 2040, 2042.

[0161] In one embodiment, during a cold start of the engine, liquid ammonia from tank 1402 (not shown in Figure 20) flows to expansion valves 2016 and 2032. The expansion valves 2016 and 2032 release pressure from the liquid ammonia, thereby allowing the liquid ammonia to expand or change state to a gaseous form.

[0162] When the expansion valve 2016 is open, gaseous ammonia flows out of the expansion valve 2016 and through the supply line 2020 to the plate heat exchange unit 2018. In one embodiment, the plate heat exchange unit 2018 preheats the low-temperature gaseous ammonia before supplying it further downstream to the electrocatalyst unit 1420 and / or the heat exchange catalyst unit 1418. The low-temperature gaseous ammonia is heated as it traverses the plate heat exchange unit 2018 to maintain its gaseous state; if the temperature of the gaseous ammonia drops below a threshold temperature, the gaseous ammonia can change to a liquid state.

[0163] In one embodiment, the high-temperature hydrogen gas mixture exiting the electrocatalyst unit 1420 is supplied to the plate heat exchange unit 2018 via a supply line 2028. The high-temperature hydrogen gas mixture is used to heat the plate heat exchange unit 2018, which then preheats gaseous ammonia as described herein. The plate heat exchange unit 2018 provides a dual function: it cools the high-temperature hydrogen gas mixture produced in the electrocatalyst unit 1420 and also preheats the low-temperature gaseous ammonia received from the ammonia tank 1402.

[0164] However, the plate heat exchange unit 2018 is used in preferred embodiments because it has a structure consisting of a series of parallel plates that enable heat exchange via parallel flow of a mixture of low-temperature gaseous ammonia and high-temperature hydrogen gas. In another embodiment, the plate heat exchange unit 2018 can be configured so that heat exchange occurs via counterflow of a mixture of low-temperature gaseous ammonia and high-temperature hydrogen gas.

[0165] In one embodiment, the plate heat exchange unit 2018 can provide a single path of two gas flows, or multiple paths such as a double or triple path.

[0166] Preheated gaseous ammonia flows from the plate heat exchange unit 2018 through the supply line 2024 to the respective heat exchange catalyst units 1418. As described herein, the heat exchange catalyst unit 1418 receives exhaust gas from the engine 2002 through the exhaust manifold 2010. When the exhaust gas reaches a threshold temperature for the ammonia cracking process, the preheated gaseous ammonia is cracked in the heat exchange catalyst unit 1418, and the resulting hydrogen gas mixture flows from the heat exchange catalyst unit 1418 through the supply line 2026 to the hydrogen inlet of the electrocatalyst unit 1420.

[0167] In one embodiment, when the hydrogen gas mixture flows from the heat exchange catalyst 1418 to the electrocatalytic unit 1420, the electrocatalytic unit 1420 does not perform the ammonia cracking process, and the current draw within the electrocatalytic unit is minimal or zero.

[0168] The high-temperature hydrogen gas mixture exits the electrocatalyst unit 1420 and continues flowing through the supply line 2028 to the plate heat exchange unit 2018. As the high-temperature hydrogen gas mixture enters the plate heat exchange unit 2018 and traverses it, it is cooled as a result of heat exchange with the low-temperature gaseous ammonia flowing from the ammonia tank 1402 through the plate heat exchange unit 2018. The cooled hydrogen gas mixture then exits the plate heat exchange unit 2018 and flows through the supply line 2030 to the respective hydrogen fuel rails 2006.

[0169] In one embodiment, when the expansion valve 2032 is open, the cryogenic gaseous ammonia exits the expansion valve 2032 and flows through the supply line 2036 to the evaporator 2034. The evaporator 2034 functions to preheat the cryogenic gaseous ammonia, which then flows through the supply line 2038 to the respective ammonia fuel rails 2008. The cryogenic gaseous ammonia is heated as it crosses the evaporator 2034 to maintain its gaseous state; if the temperature of the gaseous ammonia drops below a threshold temperature, the gaseous ammonia can change to a liquid state. In one embodiment, the coolant in the evaporator 2034 flows downstream to a radiator (not shown in Figure 20) through supply lines 2040, 2042.

[0170] In another embodiment, other types of heating units or mechanisms can be used to preheat the cold gaseous ammonia from the ammonia tank 1402 instead of the evaporator 2034. For example, the supply line from the ammonia tank 1402 to the ammonia fuel rail 2008 can be coupled to an in-line heater (also known as a line heater or flow-through heater), or the supply line can be wrapped or covered with heating tubing, coil heaters and the like. In another example, heating units such as plate heat exchangers, spiral heat exchangers, tubular heat exchangers, scraped surface heat-exchangers, microwave heaters, electric heaters and the like can be used to preheat the ammonia before supplying it to the ammonia fuel rail 2008.

[0171] In another embodiment, the plate heat exchange unit 2018 includes an outlet that supplies preheated ammonia directly to the ammonia fuel rail 2008.

[0172] In one embodiment, ammonia flowing from the evaporator 2034 to the ammonia fuel rail 2008 and hydrogen flowing from the plate heat exchange unit 2018 to the hydrogen fuel rail 2006 are used as co-fuels and supplied to an injection system in the intake manifold 2004. The injection system (not shown in Figure 20) can include various fuel injector configurations, and in one embodiment, it includes two ammonia fuel injectors and one hydrogen fuel injector for each cylinder. In another embodiment, the injection system includes one ammonia fuel injector and one hydrogen fuel injector for each cylinder. In yet another embodiment, the injection system includes one ammonia fuel injector and two hydrogen fuel injectors for each cylinder.

[0173] The injection system configurations described herein are not intended to be limiting in any way, and the number of fuel injectors in each cylinder may vary depending on the power and efficiency requirements of the specific engine used and the type of engine implemented in the onboard ammonia cracking system 1400.

[0174] For example, the number of fuel injectors per cylinder can be based on (i) the flow rate of the specific injector type used and / or (ii) the engine size, so that an appropriate volume of hydrogen gas mixture can be administered to each cylinder. When the engine size and the corresponding power output of the engine are relatively small, a smaller amount of hydrogen gas mixture is required per cylinder compared to a larger engine with greater power output. Therefore, fewer fuel injectors can potentially be used for smaller engines compared to larger engines. For example, for an engine with 12 or more cylinders, three or more onboard ammonia cracking systems can potentially be used.

[0175] In one embodiment, the injection system can utilize port injection, direct injection, or a combination of both for each cylinder to supply hydrogen and ammonia as cofuels.

[0176] However, it should be noted that while the engine 2002 shown in Figures 20-23 is a V8 engine, this description is merely illustrative and not intended to limit the engine in any way. For example, engine 2002 can be a V-engine or inline engine (i.e., an in-line engine) with any number of cylinders, from 2 to a maximum of 24. The number of onboard ammonia cracking systems 1400 used within engine compartment 2000 depends on the number of cylinders and cylinder banks in engine 2002. For example, in the case of a V4 engine, a single onboard ammonia cracking system 1400 can be used to supply a hydrogen gas mixture as fuel or as co-fuel with ammonia to each cylinder bank in the intake manifold 2004.

[0177] In one embodiment, both onboard ammonia cracking systems 1400a, b operate in parallel with each other. In another embodiment, an electronic controller and / or vehicle ECU can selectively deactivate one of the onboard cracking systems based on sensor readings related to the throughput, pressure, temperature, flow rate, cracking efficiency, and similar of the hydrogen gas mixture to optimize the flow rate of hydrogen supplied to the injection system.

[0178] Figure 21 is a top view of a dual onboard ammonia cracking system 1400a, b, which is installed in the internal combustion engine compartment 2000 shown in Figure 20, according to one embodiment of the present invention.

[0179] Figure 22 is a side view of dual onboard ammonia cracking systems 1400a and 1400b, installed in the internal combustion engine compartment 2000 shown in Figure 20, according to one embodiment of the present invention. The right bank onboard ammonia cracking system 1400b is prominently shown in Figure 22.

[0180] Figure 23 is a front view of a dual onboard ammonia cracking system 1400a, b, which is installed in the internal combustion engine compartment 2000 shown in Figure 20, according to one embodiment of the present invention.

[0181] Figure 24 is a block diagram of an engine cooling system 2400, according to one embodiment of the present invention, which utilizes ammonia as a heat exchange medium and includes a radiator 2404. In one embodiment, an evaporator 2034 vaporizes liquid ammonia and supplies the resulting gaseous ammonia to the ammonia fuel rail 2008 of the engine 2002. The evaporator 2034 also functions as a heat exchange unit between the low-temperature ammonia received from the liquid ammonia tank 1402 and the high-temperature engine coolant output from the engine 2002.

[0182] In one embodiment, cryogenic liquid ammonia flows from a liquid ammonia tank 1402 through a supply line 2402 to an expansion valve 2032. The expansion valve 2032 removes pressure from the cryogenic liquid ammonia, resulting in cryogenic mixed phase (i.e., liquid and gaseous) ammonia. The cryogenic mixed phase ammonia flows from the expansion valve 2032 through a supply line 2036 to an evaporator 2034.

[0183] In one embodiment, the radiator 2404 receives high-temperature coolant from the engine 2002 via a supply line 2406. The high-temperature engine coolant flows from the radiator 2404 to the evaporator 2034 via a supply line 2408.

[0184] In one embodiment, the evaporator 2034 is in the form of a plate heat exchange unit having a structure consisting of a series of parallel plates that enable heat exchange via parallel flows of low-temperature ammonia and high-temperature engine coolant. In another embodiment, the evaporator 2034 may be configured so that heat exchange occurs by counterflow of low-temperature ammonia and high-temperature engine coolant.

[0185] In one embodiment, the evaporator 2034 can provide a single or multiple (i.e., double or triple) flow of ammonia and coolant.

[0186] As the high-temperature engine coolant and low-temperature ammonia traverse the evaporator 2034, heat is transferred from the high-temperature engine coolant to the low-temperature ammonia, thereby cooling the engine coolant.

[0187] As heat is transferred from the engine coolant to the low-temperature ammonia mixture, the ammonia mixture is heated and vaporizes, becoming gaseous ammonia. The resulting gaseous ammonia is kept in a gaseous state because it is continuously preheated due to the continuous transfer of heat from the engine coolant as both fluids traverse the evaporator 2034. If the temperature of the gaseous ammonia drops below the threshold temperature, the gaseous ammonia can change back into a liquid state.

[0188] The cooled engine coolant is supplied back to the radiator 2404 via supply line 2410, while preheated gaseous ammonia is supplied to the ammonia fuel rail 2008 via supply line 2038 and then to the injection system in the intake manifold 2004 of the engine 2002.

[0189] Furthermore, the cooled engine coolant is supplied to the engine 2002 from the radiator 2404 via supply line 2412. The cooled engine coolant is heated as it transfers heat from the components of the engine 2002. The hot engine coolant flows back to the radiator 2404 via supply line 2406, and then flows to the evaporator 2034 via supply line 2408, where the heat exchange process described herein is repeated.

[0190] Therefore, the onboard ammonia cracking system 1400 not only utilizes ammonia as a co-fuel (i.e., preheated gaseous ammonia via supply line 2038) along with hydrogen supplied to engine 2002, but also utilizes ammonia as a heat exchange medium for transferring heat from the high-temperature engine coolant.

[0191] Thus, the radiator 2404 of the present invention can have a smaller size, weight, and footprint than conventional radiators. A smaller radiator allows for a smaller grille footprint (i.e., a smaller size and / or dimensions of the grille or air intake opening), which in turn allows for a more streamlined front end of the vehicle. A streamlined front end can improve the aesthetic appearance and the aerodynamic characteristics of the vehicle.

[0192] In another embodiment, as shown in Figure 25, the radiator 2404 shown in Figure 24 is not required. The hot engine coolant flows from the engine 2002 to the evaporator 2034 via the supply line 2502 and is cooled as described herein. The cooled engine coolant is supplied back to the engine 2002 via the supply line 2504, where heat from the components of the engine 2002 is transferred to the engine coolant.

[0193] Eliminating the radiator 2404 allows the front of the vehicle to be free of a grille or air intake opening, enabling a streamlined front end, which can improve the aesthetic appearance and the aerodynamic characteristics of the vehicle.

[0194] For example, the front of the vehicle according to the present invention can more easily accommodate an air dam and / or splitter by increasing the usable surface area of ​​the front due to a smaller grille footprint or the elimination of the grille. For example, air dams and splitters balance the distribution of forward and rear downforce by altering the airflow passing under the vehicle body. An air dam is a fluid barrier structure mounted on or integrated into the lower part of the vehicle's front-end bumper structure and extending downward to the vicinity of the roadway. Also known as a front spoiler, an air dam improves the vehicle's aerodynamic characteristics and stability by blocking and redirecting the turbulent airflow under the vehicle chassis. A splitter, on the other hand, is a flat extension component that extends to the lower part of the front bumper and extends forward and parallel to the ground. The splitter acts as a wedge that forces high-pressure air upward and over the vehicle, and high-speed, low-pressure air downward on the vehicle, resulting in a net, reliable downforce.

[0195] Improving the aerodynamic characteristics of the front of a vehicle by reducing the grille footprint or eliminating the grille altogether can improve performance and efficiency in several ways: 1. Improved Fuel Efficiency - Reducing drag on the vehicle requires less power from the engine, which improves fuel economy. On average, aerodynamics can improve fuel economy by 0.1 to 0.3 miles (0.16 to 0.48 kilometers) per gallon (3.79 liters). 2. Increased top speed - With less drag, the vehicle can reach a higher top speed. 3. Improved Maneuverability and Stability - Controlling lift can improve the maneuverability and stability of the vehicle, especially when dealing with side winds. 4. Improved tire grip - Aerodynamic downforce can increase tire grip without adding weight to the vehicle. 5. Reduced Noise - Aerodynamic characteristics can help minimize wind noise and other noise emissions.

[0196] Figure 26 is a perspective view of the front section 2600 of a vehicle equipped with a grille 2602 according to one embodiment of the present invention. The grille 2602 may have an upper grille member and a lower grille member. In another embodiment, the grille 2602 may include only a single grille member. Although a pickup truck is shown in Figure 26, the vehicle can be any type of motor vehicle, such as a passenger car, sports utility vehicle, sedan, coupe, heavy-duty truck, van, ship, aircraft and the like.

[0197] Figure 27 is a perspective view of a louver system 2704 for a grille 2602 according to one embodiment of the present invention. The front of the vehicle 2600 includes a radiator 2404 mounted on a frame member 2702 adjacent to the engine compartment. The frame member 2702 has upper and lower grille openings 2706 (corresponding to the upper and lower grille members shown in Figure 26), which provide ambient cooling airflow to the radiator 2404.

[0198] In one embodiment, a separate louver system 2704 is installed within each grille opening 2706. The louver system 2704 regulates the cooling airflow to the radiator 2404. The louver system 2704 includes a series of individual louvers 2708 that can be controlled to rotate or swivel to adjust the amount and / or rate of cooling airflow supplied to the radiator 2404. For example, the louvers 2708 can be closed to prevent cooling airflow from reaching the radiator 2404, fully open to maximize the cooling airflow supplied to the radiator 2404, or partially open to limit the cooling airflow supplied to the radiator 2404.

[0199] In one embodiment, the louver system 2704 can be controlled by the ECU and automatically adjusted based on the temperature detected from the engine 2002 and / or engine components. For example, if the engine temperature is above the optimal operating range, the louver 2708 can be opened to allow more cooling airflow to reach the radiator 2404 and promote engine cooling. However, if the engine temperature is below the optimal operating range, the louver 2708 can be closed to limit or block the cooling airflow, as the heat exchange occurring in the evaporator 2034 provides the engine 2002 with sufficiently cooled engine coolant and maintains the optimal operating temperature.

[0200] Conversely, in low ambient environments or during a cold start of engine 2002, it may be necessary to raise the engine temperature to the optimal operating range. When engine 2002 is first started and is substantially the same temperature as the ambient environment, engine 2002 is the least fuel-efficient (especially when the ambient temperature is low). This reduced fuel efficiency is why it is desirable to raise the engine temperature to the optimal operating temperature relatively quickly. In this scenario, if the engine temperature is below the optimal operating range, the louvers 2708 can be closed to limit or block the cooling airflow in order to promote heating of engine 2002.

[0201] In one embodiment, the upper and lower louver systems 2704 can be controlled independently so that only one of the louvers 2708 of the louver system 2704 is operated.

[0202] In another embodiment, the vehicle operator may manually operate or control the louvers 2708, for example, to manually utilize a low-temperature air intake charger, as desired.

[0203] Figure 28 is a flowchart showing the steps for operating the louver 2708 based on the detected engine temperature according to one embodiment of the present invention. In step 2800, the temperature of the engine 2002 is detected by a temperature sensor. In step 2802, the ECU determines whether the detected engine temperature is above the optimal operating range. In one embodiment, the optimal operating range of the engine 2002 is between 87 and 107°C (190 and 225°F).

[0204] If the detected engine temperature exceeds the optimal operating range, the ECU determines the difference between the detected engine temperature and the maximum optimal operating range in step 2804. If the difference exceeds a threshold, the ECU controls the louvers 2708 to fully open in step 2806 to maximize the amount of cooling airflow supplied to the radiator 2404. This then allows the radiator 2404 to assist the cooling system 2400 in lowering the engine temperature to within the optimal operating range.

[0205] If the difference is below a threshold, the ECU controls the louvers 2708 to partially open in step 2808, thereby reducing the aerodynamic drag on the vehicle and simultaneously providing sufficient cooling airflow to the radiator 2404. Again, this then allows the radiator 2404 to assist the cooling system 2400 in lowering the engine temperature within the optimal operating range.

[0206] In one embodiment, the threshold can be a fixed value or a percentage. For example, the threshold can be a temperature 10° above the maximum optimal operating range, or a temperature 10% above the maximum optimal operating range. However, it should be noted that these thresholds are merely illustrative examples and are not intended to limit the range in any way.

[0207] After the louvers 2708 are opened either completely in step 2806 or partially in step 2808, the process continues back to step 2800, where the engine temperature is detected again.

[0208] However, if the detected engine temperature in step 2802 does not exceed the optimal operating range, the process continues to step 2810, where the louvers 2810 are closed or kept closed if they were not previously open. The process then returns to step 2800, where the engine temperature is detected again.

[0209] Figure 29 is a block diagram of an engine cooling system 2900 according to one embodiment of the present invention, which has a radiator 2404 equipped with a bypass valve 2902 and utilizes ammonia as a heat exchange medium. The engine cooling system 2900 is identical to the engine cooling system shown in Figure 25, except that the bypass valve 2902 is coupled between the evaporator 2034, the radiator 2404, and the engine 2002. The ECU can control the bypass valve 2902 based on the temperature of the engine 2002. For example, if the temperature of the engine 2002 exceeds the optimal operating range, the bypass valve 2902 can be closed, thereby allowing cooled engine coolant to flow from the evaporator 2034 through supply line 2904 and through supply line 2410 to the radiator 2404.

[0210] However, if the temperature of engine 2002 falls below the optimal operating range, the bypass valve 2902 can be opened, thereby allowing cooled engine coolant to flow from evaporator 2034 to engine 2002 via supply line 2904 and supply line 2906.

[0211] The bypass valve 2902 allows the vehicle to utilize auxiliary cooling from the radiator 2404 as needed if the engine temperature rises above the optimal operating range.

[0212] Figure 30 is a flowchart showing the steps for bypassing the radiator 2404 based on the detected engine temperature, according to one embodiment of the present invention. In step 3000, the temperature of the engine 2002 is detected by a temperature sensor. In step 3002, the ECU determines whether the detected engine temperature is above the optimal operating range. In one embodiment, the optimal operating range of the engine 2002 is between 87 and 107°C (190 and 225°F).

[0213] If the detected engine temperature exceeds the optimal operating range, the ECU determines the difference between the detected engine temperature and the maximum optimal operating range in step 3004. If the difference exceeds a threshold, the ECU controls the bypass valve 2902 to close completely, allowing the maximum amount of cooled engine coolant to flow from the evaporator 2034 to the radiator 2404. This then allows the radiator 2404 to assist the cooling system 2400 in lowering the engine temperature to within the optimal operating range.

[0214] If the difference is below a threshold, the ECU controls the bypass valve 2902 to partially close in step 3008, thereby reducing the power consumption of the coolant pump (not shown in the figure) and simultaneously allowing the radiator 2404 to assist the cooling system 2900 in lowering the engine temperature within the optimal operating range.

[0215] In one embodiment, the threshold can be a fixed value or a percentage. For example, the threshold can be a temperature 10° above the maximum optimal operating range, or a temperature 10% above the maximum optimal operating range. However, it should be noted that these thresholds are merely illustrative examples and are not intended to limit the range in any way.

[0216] After the bypass valve 2902 is closed either completely in step 3006 or partially in step 3008, the process returns to step 3000, where the engine temperature is detected again.

[0217] However, if the detected engine temperature in step 3002 does not exceed the optimal operating range, the process continues to step 3010, where the bypass valve 2902 is fully opened or, if it was not previously open, remains fully open. This process then returns to step 3000, where the engine temperature is detected again.

[0218] When the bypass valve 2902 is fully or partially opened, the total flow rate of coolant passing through the radiator 2404 can be reduced, thus reducing the amount of power required for the coolant pump and thereby improving the vehicle's fuel efficiency.

[0219] The remaining figures are provided to illustrate additional details and embodiments of the onboard ammonia cracking system.

[0220] The principles of this disclosure are shown in connection with the exemplary embodiments described herein, but the principles of the present invention are not limited thereto and include modifications, variations, or substitutions thereof.

Claims

1. A system for heat exchange between ammonia and engine coolant for an internal combustion engine, Ammonia tank for storing liquid ammonia; An expansion valve receives liquid ammonia from the ammonia tank, and the expansion valve facilitates the change of state of the liquid ammonia to gaseous ammonia; A heat exchange unit fluidly coupled to the expansion valve and the internal combustion engine, the heat exchange unit receiving gaseous ammonia from the expansion valve; and A radiator is fluidly coupled to the heat exchange unit and the internal combustion engine, the radiator receives high-temperature engine coolant from the internal combustion engine, and the radiator supplies the high-temperature engine coolant to the heat exchange unit. Equipped with, Here, heat is transferred from the high-temperature engine coolant to the gaseous ammonia within the heat exchange unit, resulting in heated gaseous ammonia and cooled engine coolant. Here, the heated ammonia gas exits the heat exchange unit and is supplied to the internal combustion engine, and At this point, the cooled engine coolant exits the heat exchange unit and is supplied to the radiator. system.

2. The system according to claim 1, wherein the heated gaseous ammonia is supplied to the internal combustion engine for use as a combustion fuel.

3. The system according to claim 1, wherein, while the internal combustion engine is in a low-temperature state, only the heated gaseous ammonia is supplied to the internal combustion engine together with hydrogen and nitrogen obtained as a result of ammonia decomposition for use as a combustion cofuel.

4. The system according to claim 1, wherein the heat exchange unit is an evaporator.

5. The system according to claim 1, wherein the heat exchange unit has a structure comprising a series of parallel plates that enable heat exchange via parallel flows of the ammonia and the high-temperature engine coolant.

6. The system according to claim 1, wherein the gaseous ammonia is preheated within the heat exchange unit, thereby maintaining its gaseous state as it traverses the heat exchange unit.

7. The system according to any one of claims 1 to 6, wherein the internal combustion engine uses only (i) the heated gaseous ammonia and (ii) constituent hydrogen and nitrogen generated from the liquid ammonia stored in the ammonia tank as combustion fuels.

8. A system for heat exchange between ammonia and engine coolant for an internal combustion engine, Ammonia tank for storing liquid ammonia; An expansion valve that receives liquid ammonia from the ammonia tank, the expansion valve that enables the state change of the liquid ammonia to gaseous ammonia; and A heat exchange unit is fluidly coupled to the expansion valve and the internal combustion engine. The heat exchange unit receives gaseous ammonia from the expansion valve and receives high-temperature engine coolant from the internal combustion engine. Equipped with, Here, heat is transferred from the high-temperature engine coolant to the gaseous ammonia within the heat exchange unit, resulting in heated gaseous ammonia and cooled engine coolant. At this point, the heated gaseous ammonia and the cooled engine coolant exit the heat exchange unit and are supplied to the internal combustion engine. system.

9. The system according to claim 8, wherein the heated gaseous ammonia is supplied to the internal combustion engine for use as a combustion fuel.

10. The system according to claim 8, wherein only the heated gaseous ammonia is supplied to an internal combustion engine for use as a combustion co-fuel together with constituent hydrogen and nitrogen obtained as a result of ammonia decomposition.

11. The system according to claim 8, wherein the heat exchange unit is an evaporator.

12. The system according to claim 8, wherein the heat exchange unit has a structure comprising a series of parallel plates that enable heat exchange via parallel flows of the ammonia and the high-temperature engine coolant.

13. The system according to claim 8, wherein, during a cold start of the internal combustion engine, only the heated gaseous ammonia and the hydrogen and nitrogen produced as a result of ammonia decomposition are supplied to the internal combustion engine for use as combustion fuel.

14. The system according to any one of claims 8 to 13, wherein the internal combustion engine utilizes (i) the heated gaseous ammonia and (ii) constituent hydrogen and nitrogen generated from the liquid ammonia stored in the ammonia tank as combustion fuels.

15. A system for heat exchange between ammonia and engine coolant for an internal combustion engine, Ammonia tank for storing liquid ammonia; An expansion valve that receives liquid ammonia from the ammonia tank, the expansion valve that enables the state change of the liquid ammonia to gaseous ammonia; and A heat exchange unit is fluidly coupled to the expansion valve and the internal combustion engine. The heat exchange unit receives gaseous ammonia from the expansion valve and receives high-temperature engine coolant from the internal combustion engine. Equipped with, Here, within the heat exchange unit, the gaseous ammonia and the high-temperature engine coolant undergo heat exchange, resulting in heated gaseous ammonia and cooled engine coolant. Here, the heated ammonia gas exits the heat exchange unit and is supplied to the internal combustion engine along with hydrogen for use as a combustion fuel. At this point, the cooled engine coolant exits the heat exchange unit and is supplied to the internal combustion engine. system.

16. The system according to claim 15, wherein the heat exchange unit is an evaporator.

17. The system according to claim 15, wherein the heat exchange unit has a structure comprising a series of parallel plates that enable heat exchange via parallel flow of the mixed phase liquid, gaseous ammonia, and the high-temperature engine coolant.

18. The system according to claim 15, wherein, during a cold start of the internal combustion engine, only the heated gaseous ammonia and the hydrogen and nitrogen produced as a result of ammonia decomposition are supplied to the internal combustion engine for use as combustion fuel.

19. The system according to claim 15, wherein the internal combustion engine uses only hydrogen produced from the heated gaseous ammonia and the liquid ammonia stored in the ammonia tank as combustion fuels.

20. The system according to any one of claims 15 to 19, wherein the heat exchange unit has a structure that enables heat exchange between the mixed phase liquid, gaseous ammonia, and the high-temperature engine coolant via counterflow.

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