Systems and methods for production of hydrogen from ammonia using dual catalyst units in series

Abstract

To solve a problem with using hydrogen in vehicles, which is that it is a low-density gas and cannot be stored as easily as liquid fossil fuels, while it is known that hydrogen can be obtained from ammonia through a process called "cracking", and to provide a system for on-board ammonia cracking for an internal combustion engine.SOLUTION: The present invention relates, in general, to a system and method for generating hydrogen from ammonia on-board vehicles, where the produced hydrogen is used as fuel source for an internal combustion engine. The present invention utilizes an electric catalyst unit to initiate an ammonia cracking process on-board during a cold start of the internal combustion engine, where a heat exchange catalyst unit is utilized once exhaust gas from the internal combustion engine is heated to a threshold temperature suitable to perform the ammonia cracking process.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Nonprovisional Patent Application No. 17 / 986,265, filed November 14, 2022, entitled "SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA ON-BOARD MOTOR VEHICLES," which in turn claims the benefit of U.S. Provisional Patent Application No. 63 / 395,820, filed August 6, 2022, entitled "SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA ON-BOARD MOTOR VEHICLES," and U.S. Provisional Patent Application No. 63 / 395,820, filed June 27, 2022, entitled "SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA ON-BOARD MOTOR VEHICLES." This application claims the benefit of U.S. Provisional Patent Application No. 63 / 355,959, filed February 21, 2022, entitled "SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA ON-BOARD MOTOR VEHICLES," and U.S. Provisional Patent Application No. 63 / 312,121, filed February 21, 2022, entitled "SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIA ON-BOARD MOTOR VEHICLES," all of which are commonly owned, the disclosures of each of which are incorporated herein by reference in their entireties.

[0002] The present invention relates generally to systems and methods for generating hydrogen from an ammonia-laden vehicle, where the produced hydrogen is used as a fuel source for an internal combustion engine. [Background technology]

[0003] [Description of Related Art] The overall increase in temperature on and above the Earth's surface represents a significant challenge facing the planet. The Earth's climate is changing significantly, primarily due to human activities, and the transportation sector plays a major role in this global warming. For example, internal combustion engines traditionally burn fossil fuels, which produce CO2, a known contributor to global warming. Over the past decade, the transportation sector has made progress in making electric and hybrid-powered vehicles available on a large scale. In general, most electric and hybrid vehicles sold today tend to produce significantly fewer global-warming emissions than most vehicles that run on fossil fuels, i.e., gasoline. However, the environmental benefits of electric and hybrid vehicles still depend primarily on how much fossil fuel is burned to charge these vehicles. For example, if vehicles are charged using a coal-intensive power grid, the environmental benefits are smaller.

[0004] Additionally, batteries and fuel cells in electrified vehicles rely on raw materials such as cobalt, lithium, and rare earth elements. These materials are associated with serious environmental and human rights issues. Cobalt, for example, is particularly problematic. Mining cobalt produces toxic waste and slag that can leach into the environment, and studies have found high rates of exposure to cobalt and other metals in communities surrounding cobalt mining and processing facilities. Removing these metals from their ores also requires a process called refining, which can release sulfur oxides and other harmful air pollutants.

[0005] In light of the ongoing environmental concerns currently associated with electrified 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 combusted. However, pure ammonia cannot be used efficiently as a fuel in small internal combustion engines, whether spark-ignition (i.e., gasoline) or compression-ignition (i.e., diesel), because it burns too slowly to complete combustion during the power stroke of a four-stroke engine operating at speeds of several thousand revolutions per minute (RPM). In other words, when ammonia burns, the combustion produces a flame with a relatively low propagation velocity. This low combustion velocity of ammonia makes combustion unstable under operating conditions of low engine load and high engine speed.

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

[0007] Hydrogen has also been proposed as a replacement for fossil fuels for use in internal combustion engines because it is extremely abundant and can match the power of gasoline or diesel, given its lower heating value. Hydrogen is known to burn approximately six times faster than gasoline, making it easy to ignite due to its high flame speed and low ignition temperature. Most importantly, hydrogen produces zero CO2 emissions when combusted.

[0008] However, the challenge with using hydrogen onboard a vehicle is that hydrogen is an extremely light, low-density gas that cannot be stored as easily as liquid fossil fuels. Hydrogen requires compression, refrigeration, or a combination of both. The use of compressed hydrogen fuel tanks onboard a vehicle inherently creates numerous safety issues, such as the risk of potential failure of the pressure vessel, hydrogen leakage in confined spaces, and the like.

[0009] 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. Given the limited power sources available onboard a vehicle, it is difficult to generate the heat required to efficiently perform ammonia cracking on board.

[0010] Therefore, there is a need for a system and method for generating hydrogen from an ammonia-powered vehicle for use as a fuel source for an internal combustion engine that addresses the aforementioned challenges and drawbacks of on-board storage of hydrogen for electrified vehicles, ammonia-fueled internal combustion engines, and hydrogen-fueled internal combustion engines. Summary of the Invention

[0011] In one embodiment, the present invention is directed to a system for on-board ammonia cracking for an internal combustion engine, the system comprising: an ammonia tank containing liquid ammonia; a heat exchange catalyst unit fluidly coupled to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine; and an electrocatalytic unit fluidly coupled in series with the heat exchange catalyst unit, wherein upon vaporization of the liquid ammonia, gaseous ammonia flows from the ammonia tank to the heat exchange catalyst unit, and if the exhaust gas has reached a temperature sufficient to perform ammonia cracking, the gaseous ammonia undergoes a cracking process in the heat exchange catalyst unit, and if the exhaust gas has not reached a temperature sufficient to perform ammonia cracking, the gaseous ammonia flows from the heat exchange catalyst unit to the electrocatalytic unit, and undergoes the cracking process in the electrocatalytic unit.

[0012] In another embodiment, the present invention is directed to a system for on-board ammonia cracking for an internal combustion engine, comprising: an ammonia tank containing ammonia; a heat exchange catalyst unit fluidly coupled to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine and receives the ammonia from the ammonia tank; and an electrocatalytic unit fluidly coupled in series with the heat exchange catalyst unit, the electrocatalytic unit having an electric heater, wherein if the exhaust gas has reached a temperature sufficient to perform ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit, and if the exhaust gas has not reached a temperature sufficient to perform ammonia cracking, the ammonia exits the heat exchange catalyst unit and flows to the electrocatalytic unit to undergo the cracking process in the electrocatalytic unit, and hydrogen produced from the cracking process flows to the internal combustion engine.

[0013] In yet another embodiment, the present invention is directed to a system for on-board ammonia cracking for an internal combustion engine, comprising: an ammonia tank containing ammonia; a heat exchange catalyst unit fluidly coupled to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine and receives the ammonia from the ammonia tank; and an electrocatalyst unit fluidly coupled in series with the heat exchange catalyst unit, the electrocatalyst unit being powered using a vehicle power grid, wherein when the exhaust gas has reached a temperature sufficient to perform ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit; and when the exhaust gas has not reached a temperature sufficient to perform ammonia cracking: (1) the ammonia is preheated in the heat exchange catalyst unit, (2) the preheated ammonia exits the heat exchange catalyst unit and flows to the electrocatalyst unit, and (3) the preheated ammonia undergoes the cracking process in the electrocatalyst unit. [Brief explanation of the drawings]

[0014] These and other embodiments of the present invention will be discussed with reference to the following illustrative and non-limiting figures, in which like elements are numbered alike.

[0015] [Figure 1] FIG. 1 is a perspective internal view of a heat exchange catalyst unit utilizing a TPMS structure.

[0016] [Figure 2] FIG. 1 is a perspective internal view of a heat exchange catalyst unit utilizing a TPMS structure, showing the flow of heated exhaust gas and gaseous ammonia through the matrix.

[0017] [Figure 3] FIG. 1 is a perspective view of a matrix having a gyroid TPMS structure.

[0018] [Figure 4]FIG. 1 is a perspective view of a matrix having an orthogonal cross-hole TPMS structure.

[0019] [Figure 5] FIG. 1 is a perspective view of a matrix with a split-pea TPMS structure.

[0020] [Figure 6] FIG. 1 is a top perspective view of a heat exchange catalyst unit utilizing a TPMS structure.

[0021] [Figure 7] FIG. 1 is a front cross-sectional view of a cylindrical heat exchange catalyst unit utilizing a TPMS structure.

[0022] [Figure 8] FIG. 1 is a cross-sectional front view of a cylindrical heat exchange catalyst unit utilizing a TPMS structure, showing the flow of heated exhaust gas and gaseous ammonia through the matrix.

[0023] [Figure 9] FIG. 1 is a cross-sectional side view of a cylindrical heat exchange catalyst unit utilizing a TPMS structure, showing the flow of heated exhaust gas and gaseous ammonia through the matrix.

[0024] [Figure 10] FIG. 1 is a perspective view of a heat exchange catalyst unit utilizing a tube bundle structure.

[0025] [Figure 11] FIG. 1 is a front cross-sectional view of a heat exchange catalyst unit utilizing a tube bundle structure.

[0026] [Figure 12] FIG. 1 is a cross-sectional side view of a heat exchange catalyst unit utilizing a tube bundle structure.

[0027] [Figure 13] FIG. 1 is a front cross-sectional view of a two-pass heat exchange catalyst unit utilizing a tube bundle structure.

[0028] [Figure 14] FIG. 1 is a block diagram of an on-board ammonia cracking system for an internal combustion engine.

[0029] [Figure 15] FIG. 1 is a perspective view of an on-board ammonia cracking system for an internal combustion engine.

[0030] [Figure 16] FIG. 1 is a top perspective view of an on-board ammonia cracking system.

[0031] [Figure 17] FIG. 1 is a perspective side view of an on-board ammonia cracking system.

[0032] [Figure 18] FIG. 2 is a perspective view of an electrocatalytic unit.

[0033] [Figure 19] 1 is a cross-sectional view of an electrocatalytic unit.

[0034] The following definitions are intended to aid in the explanation and understanding of the defined terms in the context of the present invention. The definitions are not intended to limit these terms to a narrower scope than described throughout this specification. These definitions are intended to encompass grammatical equivalents.

[0035] As used herein, the term "motor vehicle" refers to 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, sport utility vehicles, passenger carriers, goods carriers, 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, airplanes, airships, drones, aerospace vehicles, and the like; (c) watercraft such as dry cargo vessels, liquid cargo vessels, special cargo vessels, tugboats, cruise ships, recreational boats, fishing boats, personal watercraft, jet skis, and the like; (d) locomotives; and (e) heavy machinery and equipment, generators, lawn mowers and tractors, agricultural equipment and machinery, forestry equipment and machinery, construction equipment and machinery, mining equipment and machinery, and the like.

[0036] As used herein, the term "internal combustion engine" refers to any engine, spark-ignited gasoline engine, compression-ignited diesel engine, rotary, reciprocating, or other engine, in which combustion takes place in a combustion chamber whereby the products of combustion, together with any other by-products, perform work by exerting a force on a moving surface from which mechanical power is derived by the engine. 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 the like.

[0037] As used herein, the term "catalyst" refers to a material that promotes a chemical reaction. The term "catalyst" includes, but is not limited to, one or more catalysts capable of promoting a cracking reaction, such as an ammonia cracking reaction, whether used as a base catalyst and / or an additional catalyst. For purposes of the present invention, catalysts may include, but are not limited to, non-stoichiometric lithium imide, nickel, iron, cobalt, iron-cobalt, ruthenium, vanadium, palladium, rhodium, platinum, sodium amide, and the like, as well as various combinations thereof.

[0038] As used herein, the term "cracking" refers to one or more processes in which ammonia is broken down into its constituent hydrogen and nitrogen components over at least one catalyst.

[0039] As used herein, the term "nickel alloy" refers to pure nickel or an alloy containing nickel as the primary component. The term "nickel alloy" includes, but is not limited to, Inconel® 625, Inconel® 718, Inconel® 725, and other metallic compounds containing nickel as the primary component. Inconel® is a trademark of Special Metals Corporation, Huntington, West Virginia.

[0040] As used herein, the term "triply-periodic minimal surface (TPMS)" refers to a mathematically defined structure that repeats in three dimensions, with zero mean curvature and large surface area. DETAILED DESCRIPTION OF THE INVENTION

[0041] It should be understood that aspects of the present invention are described herein with reference to figures illustrating exemplary embodiments. The exemplary embodiments herein are not necessarily intended to illustrate all embodiments in accordance with the present invention, but rather are used to describe a few exemplary embodiments. Accordingly, aspects of the present invention are not intended to be narrowly construed in light of the exemplary embodiments. Furthermore, although the present invention is described with respect to its application in an internal combustion engine for an automobile, it should be understood that the system may be implemented in any engine-driven environment that can be powered by ammonia and / or hydrogen fuel.

[0042] 1 is a perspective internal view of a heat exchange catalyst unit utilizing a TPMS structure and functioning as both a heat exchanger and a catalytic converter for performing ammonia cracking. 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 from a nickel alloy. In a preferred embodiment, the heat exchange catalyst unit 100 is made from Inconel® 625.

[0043] In one embodiment, the gaseous ammonia inlet 102, the hydrogen outlet 104, the heated exhaust gas inlet 106, and the exhaust gas outlet 108 may be made from the same metallic material as the heat exchange catalyst unit 100. In another embodiment, the gaseous ammonia inlet 102, the hydrogen outlet 104, the heated exhaust gas inlet 106, and the exhaust gas outlet 108 may be made from stainless steel, silver, bronze, and similar alloys.

[0044] Located between the inlets 102, 106 and the outlets 104, 108 is a matrix 110. The matrix 110 is formed from a widthwise surface 112 and a lengthwise surface 114 that extend generally perpendicular to one another. The surfaces 112, 114 of the matrix 110 create passages that allow the gaseous ammonia and heated exhaust gas to flow; these passages are represented by ammonia channels 116 and heated exhaust gas channels 118. Gaseous ammonia is supplied to the heat exchange catalyst unit 100 via the inlet 102, while heated exhaust gas is simultaneously supplied to the inlet 106. The gaseous ammonia traverses the matrix 110 via the ammonia channels 116, while the heated exhaust gas traverses the matrix via the heated exhaust gas channels 118. The ammonia channels 116 and the heated exhaust gas channels 118 are oriented in a generally perpendicular manner relative to one another, such that the gaseous ammonia traverses the matrix 110 approximately perpendicular to the heated exhaust gas.

[0045] In one embodiment, surfaces 112, 114 have a thickness of 1 to 2 millimeters, and each of surfaces 112, 114 may have the same thickness. In another embodiment, surfaces 112, 114 may each have a different thickness. In yet another embodiment, surfaces 112, 114 may each vary in thickness as they traverse matrix 110. For example, surfaces 112, 114 may not have a uniform thickness across the width of matrix 110, but may have thicker or thinner portions in various locations.

[0046] 1 , matrix 110 physically separates the gases passing through each of channels 116, 118, thereby providing an exceptionally large surface area throughout matrix 110 for the heated exhaust gas to exchange its heat with the gaseous ammonia. In one embodiment, surfaces 112, 114 of matrix 110 are coated with a catalyst that promotes the cracking of ammonia into its constituent hydrogen and nitrogen components. In this embodiment, surfaces 112, 114 of matrix 110 are coated with the catalyst using a washcoating or deposition technique that bonds or adheres the catalyst to surfaces 112, 114.

[0047] In another embodiment, a catalyst in the form of a separate catalytic medium is deposited in the passages forming the ammonia channels 116 and the heated exhaust gas channels 118. The separate catalytic medium may be porous, thereby allowing the gaseous ammonia and exhaust gas to pass through the catalyst as they each flow through the matrix 110.

[0048] In yet another embodiment, the surfaces 112, 114 of the matrix 110 may be coated with a catalyst described herein, and additional separate catalytic media may be deposited in the passages forming the ammonia channel 116 and the heated exhaust gas channel 118.

[0049] In one embodiment, the matrix 110 is metallic and made 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.

[0050] The materials selected for the heat exchange catalyst unit 100 and matrix 110 must be capable of withstanding the corrosive environment resulting from the high temperature, heated exhaust gases and the heated hydrogen gas produced from the cracking of ammonia.

[0051] In a preferred embodiment, the matrix 110 is in the form of a Triply Periodic Minimal Surface (TPMS), and the matrix 110 is three-dimensionally (3D) printed using powdered metal. The 3D printing process is an additive manufacturing process that uses laser sintering to selectively fuse particles of powdered metal together into the TPMS structure in a layer-by-layer manner. The TPMS structure of the matrix 110 provides a relatively large surface area with cells that can be confined within the size and shape of the heat exchange catalyst unit 100.

[0052] TPMS structures can be a variety of crystalline structures with various patterns and profiles. In the embodiment shown in FIG. 1, the TPMS is a gyroid structure. The structure may be in the form of, but not limited to, gyroid, diamond, orthogonal cross-hole, or split pea, among many others. Each of these forms has a different surface area. For example, in the embodiment shown in FIG. 1, the heat exchange catalyst unit 100 has dimensions of approximately 10 x 10 x 4 inches (25.4 x 25.4 x 10.16 centimeters). For a matrix 110 that fits within these dimensions, Table 1 provides approximate surface area values ​​for various TPMS structures that may be utilized. [Table 1] Table 1

[0053] 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 may be modified to increase or decrease the surface area of ​​the matrix 110. For example, within the same volume of the heat exchange catalyst unit 100, the individual cell sizes may be increased to increase the overall surface area of ​​the matrix 110, or conversely, the individual cell sizes may be decreased to decrease the overall surface area of ​​the matrix 110.

[0054] The TPMS structure is ideal for the matrix 110 because it allows heat to be distributed across all surfaces of the matrix 100, thereby facilitating the chemical reactions required for the ammonia cracking process. As the surface area of ​​the matrix 110 increases, inherent challenges exist in cleaning its surface after it is printed, given that the arrangement of the channels 116, 118 becomes closer to one another as the surface area increases. However, as the cell size of the matrix 110 increases, the surface area decreases, thereby reducing the throughput efficiency of the heat exchange catalyst unit 100. The surface area of ​​the matrix 110 may depend on the power requirements of the automobile and its engine.

[0055] In one embodiment, the heat exchange catalyst unit 100 is sized and dimensioned to accommodate the matrix 110 with sufficient surface area to facilitate the cracking process while still having a form factor suitable for placement within an automobile. The dimensions of the heat exchange catalyst unit 100 may vary and may range from 5 to 30 inches (12.7 to 76.2 centimeters) in width, 5 to 30 inches (12.7 to 76.2 centimeters) in length, and 0.5 to 12 inches (1.27 to 30.48 centimeters) in height.

[0056] 1, the heat exchange catalyst unit 100 has a generally square shape containing a square shaped matrix 110, but this is merely an illustrative example and is not intended to be limiting in any way. In other embodiments, the heat exchange catalyst unit 100 may be any polygonal shape, such as, for example, an oval, a rectangle, a triangle, a square, a kite shape, a trapezoid, a parallelogram, a diamond, and the like, as well as various 3D shapes, such as, for example, a cube, a rectangular prism, a sphere, a cone, and the like.

[0057] In one embodiment, the ammonia inlet 102 has a smaller diameter than the heated exhaust gas inlet 106 because the flow velocity of the exhaust gas may be several orders of magnitude greater than the flow velocity of the ammonia. The diameter, shape, and size of the inlets 102, 106 and outlets 104, 108, as well as the dimensions of the heat exchange catalyst unit 100, may vary based on the power requirements of the vehicle and its engine.

[0058] 2 is a perspective internal view of a heat exchange catalyst unit 100 utilizing a TPMS structure, showing the flow of heated exhaust gas and gaseous ammonia through the matrix. During operation, gaseous ammonia 200 is fed to inlet 102 and flows through ammonia channels 116, while heated exhaust gas 202 is simultaneously fed to inlet 106 and flows through heated gas channels 118. The heated exhaust gas 202 heats the catalyst, thereby cracking the gaseous ammonia 200 into its constituent hydrogen and nitrogen components 204. The resulting hydrogen and nitrogen components 204 exit the heat exchange catalyst unit 100 via outlet 104 and are fed to a downstream injection system for the engine, while the remaining exhaust gas 206 exits the heat exchange catalyst unit via outlet 108.

[0059] 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 cross-hole TPMS structure, and Figure 5 is a perspective view of a matrix 110 having a split-pea TPMS structure. However, it should be noted that the TPMS structures shown in Figures 1 through 5 are merely illustrative examples and are not intended to be limiting in any way.

[0060] 6 is a top perspective view of a heat exchange catalyst unit 100 utilizing a TPMS structure. In one embodiment, the heat exchange catalyst unit 100 may be manufactured by welding the inlets 102, 106 and outlets 104, 108 to a housing 600. In one embodiment, the housing 600 may include a cover (not shown in FIG. 6) that can be removed to inspect or replace the matrix 110. In another embodiment, the inlets 102, 106 and / or outlets 104, 108 may be removably attached to the housing 600, such that a variety of inlets and outlets having different dimensions, sizes, and flow characteristics may be utilized with the housing 600 in a modular manner.

[0061] 7 is a cross-sectional front view of a cylindrical heat exchange catalyst unit 700 utilizing a TPMS structure. Similar to the heat exchange catalyst unit 100 shown in FIG. 1, the cylindrical heat exchange catalyst unit 700 is metallic and made from a nickel alloy; in a preferred embodiment, the cylindrical heat exchange catalyst unit 700 is made from Inconel® 625.

[0062] In one embodiment, 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. Located between the inlets 702, 706 and the outlets 704, 708 is a matrix 710. Matrix 710 is formed from a width surface 712 and a length surface 714 that extend generally perpendicular to one another. Surfaces 712, 714 of matrix 710 create passages that allow gaseous ammonia and heated exhaust gas to flow; these passages are represented by ammonia channels 716 and heated exhaust gas channels 718.

[0063] Gaseous ammonia is fed to the cylindrical heat exchange catalyst unit 700 via inlet 702, while heated exhaust gas is simultaneously fed to inlet 706. The gaseous ammonia traverses the matrix 710 axially, while the heated exhaust gas traverses the matrix laterally.

[0064] 7, matrix 710 physically separates the gases passing through each of channels 716, 718, thereby providing an exceptionally large surface area throughout matrix 710 for the heated exhaust gas to exchange its heat with the gaseous ammonia. In one embodiment, surfaces 712, 714 of matrix 710 are coated with a catalyst that promotes the cracking of ammonia into its constituent hydrogen and nitrogen components. In this embodiment, surfaces 712, 714 of matrix 710 are coated with the catalyst using a washcoating or deposition technique that bonds or adheres the catalyst to surfaces 712, 714.

[0065] In another embodiment, a catalyst in the form of a separate catalytic media is deposited in the passages forming the ammonia channel 716 and the heated exhaust gas channel 718 .

[0066] In yet another embodiment, surfaces 712, 714 of matrix 710 may be coated with a catalyst described herein, and additional separate catalytic media may be deposited in the passages forming ammonia channel 716 and heated exhaust gas channel 718.

[0067] 8 is a cross-sectional front view of a cylindrical heat exchange catalyst unit 700 utilizing a TPMS structure, showing the flow of heated exhaust gas and gaseous ammonia through the matrix. During operation, gaseous ammonia 200 is fed to inlet 702 and flows through ammonia channels 716, while heated exhaust gas 202 is simultaneously fed to inlet 706 and flows through heated gas channels 718. The heated exhaust gas 202 heats the catalyst, thereby cracking the ammonia 200 into its constituent hydrogen and nitrogen components 204. The resulting hydrogen and nitrogen components 204 exit the heat exchange catalyst unit 700 via outlet 704 and are fed to a downstream injection system for the engine, while the remaining exhaust gas 206 exits the heat exchange catalyst unit via outlet 708.

[0068] Figure 9 is a cross-sectional side view of a cylindrical heat exchange catalyst unit 700 utilizing a TPMS structure, showing the flow of heated exhaust gas and gaseous ammonia through the matrix. As shown in Figure 9, surfaces 712, 714 of matrix 710 create ammonia channels 716 and heated exhaust gas channels 718. Given the rounded parts, fewer weld seams / joints compared to square and rectangular designs, and less susceptibility to thermal stresses, the cylindrical design may offer efficiencies for mass production.

[0069] 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 be limiting in any way. In other embodiments, the heat exchange catalyst unit 700 may be any polygonal shape, such as, for example, an oval, a rectangle, a triangle, a square, a kite, a trapezoid, a parallelogram, a rhombus, and the like, as well as various 3D shapes, such as, for example, a cube, a rectangular parallelepiped, a sphere, a cone, and the like.

[0070] 10 is a perspective view of a heat exchange catalyst unit 1000 that utilizes a tube bundle structure and functions as both a heat exchanger and a catalytic converter for performing ammonia cracking. The heat exchange catalyst unit 1000 is made of metal and, in one embodiment, includes a sidewall 1002 that includes a gaseous ammonia inlet 1004. In one embodiment, the inlet sidewall 1002 may include an additional port 1006 that may be used for a variety of functions. For example, the port 1006 may function as an inlet or may be coupled to equipment for sensing temperature, throughput, and / or pressure.

[0071] The heat exchange catalyst unit 1000 further includes a heated gas inlet 1008. In one embodiment, as will be described in more detail with reference to Figure 11, the heated exhaust gas inlet 1008 includes a divider 1010 that distributes the heated exhaust gas from the engine evenly throughout the internal tube bundle structure housed in the heat exchange catalyst unit 1000. In one embodiment, the divider 1010 may have a grid or lattice structure.

[0072] The heat exchange catalyst unit 1000 includes an exhaust gas outlet 1012 located opposite the heated gas inlet 1008 .

[0073] 11 is a cross-sectional front view of a heat exchange catalyst unit 1000 utilizing a tube bundle structure. In one embodiment, a tube bundle structure 1100 is provided inside the heat exchange catalyst unit 1000. The tube bundle structure 1100 is made up of individual tubes 1102 that extend from the sidewall 1002 along the width of the heat exchange catalyst unit 1000, perpendicular to the inlet 1008 and outlet 1012.

[0074] In one embodiment, the tube bundle structure 1100 includes rows and / or columns of tubes 1102 arranged in an offset manner, such that each adjacent row and / or column includes tubes that are offset from its neighboring tubes. This pattern maximizes the surface area that the heated exhaust gas contacts as the gas traverses the tube bundle structure 1100, thereby maximizing the amount of catalyst that is heated to facilitate the cracking process.

[0075] In one embodiment, the heat exchange catalyst unit 1000 includes at least one support structure 1104 that facilitates the 3D printing process and also provides stability against thermal stresses during operation of the heat exchange catalyst unit 1000.

[0076] 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, while the heated exhaust gas traverses the axial space inside the tubes 1102.

[0077] In one embodiment, the spaces between the tubes 1102 are filled with catalyst in the form of a separate catalytic media. In another embodiment, the tubes 1102 themselves are hollow and are also filled with a separate catalytic media.

[0078] In yet another embodiment, the exterior and / or interior surfaces of the tubes 1102 are also coated with a catalyst using washcoating or deposition techniques that cause the catalyst to bond or adhere to the surface.

[0079] 12 is a cross-sectional side view of a heat exchange catalyst unit 1000 utilizing the tube bundle structure 1100. In one embodiment, the heat exchange catalyst unit 1000 includes a sidewall 1200 opposite the sidewall 1002. The sidewall 1200 includes a hydrogen outlet 1202 and may include an additional port 1204 that may be used for a variety of functions. For example, the port 1204 may function as an outlet or may be coupled to equipment for sensing temperature, throughput, and / or pressure.

[0080] During operation, gaseous ammonia is fed into inlet 1004, while heated exhaust gas is simultaneously fed into inlet 1008. The heated exhaust gas heats the catalyst, which cracks the ammonia into its constituent hydrogen and nitrogen components. The resulting hydrogen and nitrogen components exit heat exchange catalyst unit 1000 via outlet 1202 and are fed to the downstream engine.

[0081] 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.

[0082] In one embodiment, the side walls 1002, 1200, gaseous ammonia inlet 1004, hydrogen outlet 1202, heated exhaust gas inlet 1008, divider plate 1010, exhaust gas outlet 1012, and support structure 1104 may be made from the same metallic material as the heat exchange catalyst unit 1000. In another embodiment, the side walls 1002, 1200, gaseous ammonia inlet 1004, divider plate 1010, hydrogen outlet 1202, heated exhaust gas inlet 1008, and exhaust gas outlet 1012 may be made from stainless steel, silver, bronze, and similar alloys.

[0083] Figure 13 is a front cross-sectional view of a two-pass heat exchange catalyst unit 1300 utilizing the tube bundle structure 1100. In this embodiment, a support structure 1302 includes a fascia that receives sidewalls (not shown in Figure 13). The support structure 1302 includes a divider 1304 that physically separates the tube bundle structure 1100 into a left portion 1306 and a right portion 1308. The divider 1304 extends along the width of the two-pass heat exchange catalyst unit 1300 between the two sidewalls. In this embodiment, the gaseous ammonia inlet is located in the sidewall overlying the left portion 1306, and the hydrogen outlet is located in the sidewall overlying the right portion 1308.

[0084] During operation, gaseous ammonia is fed into the gaseous ammonia inlet, while heated exhaust gas is simultaneously fed into the inlet 1008. As the ammonia traverses the left portion 1306 of the tube bundle structure 1100, the heated exhaust gas heats the catalyst, causing the ammonia to be cracked into its constituent hydrogen and nitrogen components. The remaining ammonia returns across the right portion 1308 of the tube bundle structure 1100 and continues to undergo cracking, thereby providing a two-pass cracking process. The resulting hydrogen and nitrogen components exit the two-pass heat exchange catalyst unit 1300 via the hydrogen outlet and are fed to the downstream engine.

[0085] Figure 14 is a block diagram of an on-board ammonia cracking system for an internal combustion engine. The on-board ammonia cracking system 1400 provides a mechanism for generating hydrogen from ammonia, thereby eliminating the need for a separate hydrogen tank on the vehicle.

[0086] 14, an ammonia liquid tank 1402 is mounted to a vehicle or engine, and in one embodiment, the ammonia liquid tank 1402 may be coupled to a pump 1404. In one embodiment, the tank 1402 is refillable and / or replaceable. The pump 1404 may be coupled to a port on the tank 1402 to facilitate delivery of the 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 the ammonia is not sufficient to force itself out of the tank 1402. Therefore, the pump 1404 is needed to draw or push the ammonia out of the tank 1402.

[0087] In another embodiment, an electric heater (not shown in FIG. 14) may be coupled to tank 1402, for example, to the interior of tank 1402 or to the exterior surface of tank 1402, to heat the liquid ammonia contained in tank 1402 to a temperature at which the liquid ammonia will vaporize into gaseous form.

[0088] In one embodiment, a pressure regulator 1406 is coupled to the outlet of tank 1402 and functions to control the amount and / or flow rate of ammonia drawn from tank 1402 by pump 1404. Pressure regulator 1406 monitors the pressure of the liquid ammonia in tank 1402. When the pressure drops to a threshold pressure value at which the liquid ammonia may evaporate into gaseous form, pressure regulator 1406 opens and delivers the gaseous ammonia downstream. Any remaining liquid ammonia that passes through pressure regulator 1406 is also delivered to injection system 1408 (e.g., via a T-fitting on the supply line).

[0089] In one embodiment, during a cold start of the engine, the temperature control valve 1410 receives a temperature feedback signal 1412 including a temperature reading from the electrocatalyst unit 1420. The temperature feedback signal 1412 may be generated by a temperature sensor coupled to the electrocatalyst unit 1420. When the electrocatalyst unit 1420 reaches a threshold temperature suitable for conducting an ammonia cracking process (i.e., when the temperature reading is equal to or greater than the threshold temperature), the temperature control valve 1410 opens and the gaseous ammonia passes downstream through the heat exchange catalyst unit 1418 to the electrocatalyst unit 1420 where it is heated using power supplied from the vehicle power grid 1422.

[0090] If the electrocatalytic unit 1420 has not reached the threshold temperature, then the temperature control valve 1410 continues to monitor the temperature feedback signal 1412 and prevents gaseous ammonia from proceeding downstream. Cold start operation is described in more detail herein.

[0091] In one embodiment, the temperature of the heated exhaust gas entering the heat exchange catalytic unit 1418 is determined based on the current draw at the electrocatalytic unit 1420, where the current draw indicates how effective the heat exchange catalytic unit 1418 is at cracking gaseous ammonia.

[0092] 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 will not perform the ammonia cracking process and therefore will draw minimal or no current.

[0093] However, when gaseous ammonia passes from the heat exchange catalytic unit 1418 to the electrocatalytic unit 1420, the ammonia cracking process takes place and electrical current is drawn to heat a heating element provided within the electrocatalytic unit 1420.

[0094] However, during normal or high load operating conditions of the engine (i.e., not during cold start or low load operating conditions), the on-board ammonia cracking system 1400 does not utilize the electrocatalytic unit 1420 to perform the ammonia cracking process, as the heat exchange catalytic unit 1418 will have been heated to a threshold temperature by the heated exhaust gases from the engine, and the heat exchange catalytic unit 1418 will perform the ammonia cracking process.

[0095] The heat exchange catalyst unit 1418 referenced in FIG. 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, or the two-pass heat exchange catalyst unit 1300 utilizing a tube bundle structure.

[0096] A pressure control valve 1414 is positioned in series with the temperature control valve 1410 and controls the amount of gaseous ammonia delivered to the heat exchange catalyst unit 1418 .

[0097] In one embodiment, the pressure control valve 1414 receives a pressure feedback signal 1416 from a heat exchange catalyst unit 1418. For example, the heat exchange catalyst unit 1418 may be coupled to a pressure transducer or the like (not shown in FIG. 14) that generates the pressure feedback signal 1416.

[0098] In one embodiment, to facilitate cold starting of the on-board 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 a catalyst so that gaseous ammonia can be cracked, with the resulting hydrogen being supplied to a downstream injection system for the engine. The engine can then combust the hydrogen to power the engine, which in turn supplies heated exhaust gas to the on-board ammonia cracking system 1400.

[0099] In one embodiment, the electrocatalytic unit 1420 is coupled to a vehicle power grid 1422, such as a conventional vehicle battery. In another embodiment, the electrocatalytic unit 1420 may be heated via a supplemental heat / power source, such as a renewable energy source, a portable battery source, an on-board electric battery pack, and / or a rechargeable battery.

[0100] In addition to facilitating cold starts of the on-board ammonia cracking system 1400, the electrocatalytic unit 1420 is utilized to assist the heat exchange catalyst unit 1418 during low engine load operating conditions, such as when the vehicle is stopped, slowing down, or idling. For example, during low load operating conditions, the engine exhaust gas temperature may drop significantly. The reduced temperature of the exhaust gas flowing into the heat exchange catalyst unit 1418 during these low load operating conditions may not be sufficient for the catalyst to crack the ammonia. In one embodiment, depending on the particular catalyst utilized, the exhaust gas temperature needs to be at least 400°C to 700°C to perform the ammonia cracking process, and in a preferred embodiment, the exhaust gas temperature is at least 600°C to perform the ammonia cracking process.

[0101] In this scenario, the cold gaseous ammonia would pass through heat exchange catalyst unit 1418 and be supplied downstream to electrocatalyst unit 1420, which would be heated using power supplied from the vehicle power grid 1422. Once electrocatalyst unit 1420 has heated to a suitable threshold temperature to carry out the ammonia cracking process, temperature control valve 1410 opens, allowing the gaseous ammonia to be delivered to heat exchange catalyst unit 1418 and ultimately to electrocatalyst unit 1420. Electrocatalyst unit 1420 then carries out the ammonia cracking process, and the resulting hydrogen is supplied to a downstream injection system for the engine.

[0102] An ammonia cracking process occurs within the heat exchange catalytic unit 1418 when the exhaust gases flowing into the heat exchange catalytic unit 1418 reach a threshold temperature suitable for carrying out the ammonia cracking process, such as during normal or high load engine operating conditions. The resulting hydrogen and nitrogen pass downstream to an electrocatalytic unit 1420 and further downstream to a gas-to-liquid or gas-to-gas heat exchange unit 1428 and then to an injection system 1430 for the engine. In one embodiment, the gas-to-liquid or gas-to-gas heat exchange unit 1428 can utilize engine coolant and / or engine radiator, or input ammonia gas or liquid to facilitate the heat exchange process.

[0103] In one embodiment, pressure regulator 1406 may be controlled using an electric servo motor to provide a steady flow of gaseous ammonia from tank 1402. In another embodiment, a pulse width modulated 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 FIG. 14 ).

[0104] In one embodiment, the electronic controller may be coupled to various components of the on-board ammonia cracking system 1400 to receive inputs from sensors such as temperature and pressure transducers that may be coupled to the pressure regulator 1406, the temperature control valve 1410, the pressure control valve 1414, and the heat exchange catalyst unit 1418 and / or the electrocatalytic unit 1420.

[0105] In another embodiment, the electronic controller may be integrated in hardware and software with the vehicle's electronic control unit (ECU), where the flow rate of hydrogen delivered to the engine's injection system may be measured and reported back to the ECU as a mechanism for controlling the injection strategy.

[0106] 15-17 are various perspective views of the on-board ammonia cracking system 1400 for an internal combustion engine described in FIG.

[0107] Figure 18 is a perspective view of an electrocatalytic unit. In one embodiment, electrocatalytic unit 1800 comprises a housing 1802 that surrounds a ceramic tube 1900 (shown in Figure 19). In one embodiment, housing 1802 is a metal housing.

[0108] In one embodiment, electrocatalytic unit 1800 includes a gaseous ammonia inlet 1804 and a hydrogen outlet 1806 at an opposite end of electrocatalytic unit 1800. The electrocatalytic unit further includes power feedthroughs 1808, 1810 for a heating element 1904 (shown in FIG. 19 ). In one embodiment, electrocatalytic unit 1800 may include radial fittings 1812, 1814 that may be used for a variety of functions. For example, radial fittings 1812, 1814 may function as inlets, outlets, or may be coupled to instruments for sensing temperature, throughput, and / or pressure. In one embodiment, radial fitting 1812 may include or be coupled to a thermocouple, and radial fitting 1814 may include or be coupled to a pressure transducer, respectively.

[0109] 19 is a cross-sectional view of an electrocatalytic unit 1800. In one embodiment, a ceramic tube 1900 contains the catalyst. The ceramic tube 1900 acts as an insulator, allowing heat to be focused and reflected towards the catalyst, thereby heating it.

[0110] In one embodiment, a first screen 1901 and a second screen 1902 are provided at opposite ends of a ceramic tube 1900. Screens 1901, 1902 may be made from wire, wire mesh, or another metallic mesh or matrix structure. In one embodiment, screens 1901, 1902 may be made from a nickel alloy that is resistant to the heated hydrogen gas produced from the cracking of ammonia and to the gaseous ammonia itself.

[0111] In one embodiment, a heating element 1904 is also provided inside the ceramic tube 1900. An electric current is passed through the heating element 1904 to heat it to a threshold temperature suitable for carrying out the ammonia cracking process. Because nickel maintains a fairly constant resistance at high temperatures, as opposed to steel, which becomes less resistive at high temperatures, in one embodiment, the heating element 1904 and screens 1901, 1902 are made from a nickel alloy or other material that is resistant to hydrogen and ammonia. Furthermore, nickel alloys may have greater corrosion resistance during exposure to ammonia and hydrogen at high temperatures (such as temperatures above 600°C, which may be achieved in the electrocatalytic unit 1800).

[0112] In a 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 may be made from the same material. Alternatively, the heating element 1904 and the screens 1901, 1902 may be made from different materials.

[0113] In one embodiment, the heating element 1904 may be an air process heater, a cartridge heater, a tubular 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.

[0114] In one embodiment, each end of the heating element 1904 contacts a power feedthrough 1808, 1810. The power feedthroughs 1808, 1810 provide electricity to energize or heat the heating element 1904.

[0115] In one embodiment, the heating element 1904 is regulated via an electronic controller coupled to the power feedthroughs 1808, 1810 by utilizing readings from thermocouples coupled to the radial fixtures 1812, such that the heating element 1904 maintains a threshold temperature suitable for carrying out the ammonia cracking process. The threshold temperature may range from 400°C to 700°C, and in a preferred embodiment, the threshold temperature is at least 600°C.

[0116] In one embodiment, an electronic controller may be used to control an electric expansion valve (not shown in FIG. 19 ) coupled to inlet 1804 using readings from a pressure transducer coupled to radial fixture 1814 and / or a thermocouple coupled to radial fixture 1812. The electric expansion valve is used to maintain the vapor pressure of the gaseous ammonia received by electrocatalysis unit 1800 from the heat exchange catalyst unit when the gaseous ammonia reaches a threshold temperature. At these threshold temperature and pressure values, the electric expansion valve is opened to allow the ammonia to enter ceramic tube 1900.

[0117] In one embodiment, a catalyst, such as a separate catalytic media, is deposited within the ceramic tubes. Gaseous ammonia undergoes a chemical reaction with the catalyst inside the ceramic tubes 1900, and the resulting hydrogen and nitrogen components exit the electrocatalytic unit 1800 via outlet 1806 and are supplied to a downstream injection system for the engine.

[0118] In another embodiment, the heating element 1904 is coated with a catalyst that promotes the ammonia cracking process, and no separate catalyst is provided inside the ceramic tube 1900. In this embodiment, the catalyst is coated onto the heating element 1904 using a washcoating or deposition technique that bonds or adheres the catalyst to the surface of the heating element 1904.

[0119] In one embodiment, the heating element 1904 is a strip heater. The heating element 1904 may be coated with a catalyst on all surfaces, or alternatively, a catalyst sleeve may be disposed on the strip heating element 1904. In one embodiment, the strip heating element 1904 has a relatively low heat transfer efficiency, which may maintain a high skin (or boundary layer) temperature of the catalyst coating the exterior of the strip heating element 1904.

[0120] In another embodiment, the heating element 1904 is a spiral heater, a coil heater, or an air process heater, where the interior walls (including the integrated heating element) are coated with a catalyst.

[0121] In yet another embodiment, the catalyst is coated onto the interior wall of the ceramic tube 1900. In this embodiment, the catalyst is coated onto the interior wall of the ceramic tube 1900 using a washcoating or deposition technique that bonds or adheres the catalyst to the wall surface.

[0122] The remaining figures are provided to show additional details and embodiments of the on-board ammonia cracking system.

[0123] Although the principles of the present disclosure have been described in connection with the exemplary embodiments set forth herein, the principles of the present invention are not limited thereto but include any modifications, variations, or permutations thereof.

Claims

1. 1. A system for on-board ammonia cracking for an internal combustion engine, comprising: an ammonia tank containing liquid ammonia; a heat exchange catalyst unit fluidly coupled to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine; and an electrocatalytic unit fluidly coupled in series with said heat exchange catalytic unit; Equipped with When the liquid ammonia is vaporized, gaseous ammonia flows from the ammonia tank to the heat exchange catalyst unit; When the exhaust gas has reached a temperature sufficient to perform ammonia cracking, the gaseous ammonia undergoes a cracking process in the heat exchange catalyst unit; If the exhaust gas has not reached a temperature sufficient to perform ammonia cracking, the gaseous ammonia will exit the heat exchange catalytic unit and flow to the electrocatalytic unit where it will undergo the cracking process. system.

2. The system of claim 1 , wherein the ammonia tank is coupled to a pump.

3. The system of claim 1 , wherein the electrocatalytic unit comprises an electric heater.

4. The system of claim 1 , wherein the heat exchange catalyst unit comprises a matrix including a series of rows and columns.

5. The system of claim 4 , wherein the surface of the matrix is ​​coated with a catalyst.

6. 2. The system of claim 1, wherein the heat exchange catalyst unit has a tube bundle structure, the tube bundle structure including individual tubes extending along a width of the heat exchange catalyst unit perpendicular to an inlet that receives the exhaust gas.

7. 7. The system of claim 1, wherein the temperature sufficient to perform ammonia cracking is at least 600°C.

8. 1. A system for on-board ammonia cracking for an internal combustion engine, comprising: an ammonia tank containing ammonia; a heat exchange catalyst unit fluidly coupled to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine and receives the ammonia from the ammonia tank; and an electrocatalytic unit fluidly coupled in series with the heat exchange catalyst unit, the electrocatalytic unit having an electric heater; Equipped with When the exhaust gas has reached a temperature sufficient to perform ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit; If the exhaust gas has not reached a temperature sufficient to perform ammonia cracking, the ammonia exits the heat exchange catalytic unit and flows to the electrocatalytic unit where it undergoes the cracking process; The hydrogen produced from the cracking process flows to the internal combustion engine. system.

9. 9. The system of claim 8, wherein when the ammonia undergoes the cracking process in the heat exchange catalytic unit, the resulting hydrogen and nitrogen exit the heat exchange catalytic unit and flow to the electrocatalytic unit.

10. 9. The system of claim 8, wherein when the ammonia undergoes the cracking process in the electrocatalytic unit, the ammonia is preheated in the heat exchange catalytic unit before flowing to the electrocatalytic unit.

11. 9. The system of claim 8, wherein the temperature sufficient to perform ammonia cracking ranges from 400°C to 700°C depending on the particular catalyst provided in the heat exchange catalytic unit or the electrocatalytic unit.

12. 9. The system of claim 8, wherein the electric heater is selected from the group consisting of an air process heater, a cartridge heater, a tubular heater, a band heater, a strip heater, an etched foil heater, a thin film heater, a ceramic heater, a ceramic fiber heater, and a resistance wire.

13. The system of claim 8 , wherein the heat exchange catalyst unit comprises a matrix including a series of rows and columns.

14. 14. The system of any one of claims 8 to 13, wherein the heat exchange catalyst unit has a tube bundle structure with individual tubes extending along a width of the heat exchange catalyst unit perpendicular to an inlet for the exhaust gases.

15. 1. A system for on-board ammonia cracking for an internal combustion engine, comprising: an ammonia tank containing ammonia; a heat exchange catalyst unit fluidly coupled to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine and receives the ammonia from the ammonia tank; and an electrocatalyst unit fluidly coupled in series with the heat exchange catalyst unit, the electrocatalyst unit being powered using the vehicle power system; Equipped with When the exhaust gas has reached a temperature sufficient to perform ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit; If the exhaust gas does not reach a temperature sufficient to perform ammonia cracking: (1) the ammonia is preheated in the heat exchange catalyst unit; (2) the preheated ammonia exits the heat exchange catalytic unit and flows to the electrocatalytic unit; (3) The preheated ammonia undergoes the cracking process in the electrocatalytic unit. system.

16. 16. The system of claim 15, wherein the electrocatalytic unit comprises an electric heater.

17. 17. The system of claim 16, wherein the electric heater is selected from the group consisting of an air process heater, a cartridge heater, a tubular heater, a band heater, a strip heater, an etched foil heater, a thin film heater, a ceramic heater, a ceramic fiber heater, and a resistance wire.

18. 16. The system of claim 15, wherein the electrocatalytic unit has a separate catalytic media deposited therein.

19. 16. The system of claim 15, wherein the temperature sufficient to perform ammonia cracking ranges from 400°C to 700°C depending on the particular catalyst provided in the heat exchange catalytic unit or the electrocatalytic unit.

20. 20. The system of any one of claims 15 to 19, wherein hydrogen resulting from the cracking process flows to the internal combustion engine for use as a combustion co-fuel along with the ammonia.

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