System and method for hydrogen production from ammonia using tandem dual catalyst units

Abstract

The present invention generally relates to systems and methods for generating hydrogen from on-board ammonia, wherein the generated hydrogen is used as a fuel source for an internal combustion engine. The invention employs an electrocatalyst unit to initiate an on-board ammonia cracking process during cold start of the internal combustion engine, and once exhaust gas discharged from the internal combustion engine is heated to a threshold temperature suitable for the ammonia cracking process, the ammonia cracking process is carried out with a heat exchange catalyst unit.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. non-provisional patent application No. 17 / 986,265, filed on November 14, 2022, entitled “SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIAON-BOARD MOTOR VEHICLES,” which claims the benefit of 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 AMMONIAON-BOARD MOTOR VEHICLES,” and U.S. provisional patent application No. 63 / 395,820, filed on June 27, 2022, entitled “SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIAON-BOARD and the benefit of U.S. Provisional Patent Application No. 63 / 355,959, entitled “SYSTEMS AND METHODS FOR THE CATALYTIC PRODUCTION OF HYDROGEN FROM AMMONIAON-BOARD MOTOR VEHICLES” filed on February 21, 2022, all of which are commonly owned, and the entire contents of each disclosure are incorporated herein by reference. Technical Field

[0003] The present invention generally relates to systems and methods for generating hydrogen from on-board ammonia, wherein the generated hydrogen is used as a fuel source for an internal combustion engine. Background Art

[0004] The increase in overall temperature at and above the Earth's surface is a serious challenge facing the planet. The Earth's climate is undergoing significant changes, primarily due to human activities, and the transportation sector plays a prominent role in global warming. For example, internal combustion engines have historically burned fossil fuels, which in turn produce CO2, a well-known contributor to global warming. Over the past decade, the transportation industry has made progress in the mass adoption of electric and hybrid vehicles. In general, most electric and hybrid vehicles sold today produce significantly fewer global warming emissions than most vehicles that use 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 the vehicle is charged using a high coal-consuming grid, the environmental benefits are reduced.

[0005] In addition, batteries and fuel cells for 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. For example, the problem is particularly acute with cobalt. Mining cobalt creates harmful tailings and slag that seep into the environment, and studies have found high rates of exposure to cobalt and other metals in communities around cobalt mining and processing facilities. Extracting such metals from ores also requires a process called smelting, which emits sulfur oxides and other harmful air pollutants.

[0006] Given the ongoing environmental concerns surrounding electrified vehicles, ammonia has been suggested as a replacement for fossil fuels for use in internal combustion engines because of its relatively high energy density and zero CO2 emissions when burned. However, pure ammonia cannot be effectively used as a fuel in small internal combustion engines, either 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 running at thousands of revolutions per minute (RPM). In other words, when ammonia burns, the flame propagation velocity produced by the combustion is relatively low. This low burning rate of ammonia results in combustion instabilities under low engine load and high RPM operating conditions.

[0007] Previous methods of using ammonia to fuel combustion engines required mixing the ammonia with a secondary combustion promoter fuel, such as gasoline, LPG, or diesel. However, the demand for the secondary combustion promoter fuel fluctuates with changes in engine load and engine speed, which can cause control problems. Therefore, the use of a secondary combustion promoter fuel generally requires additional control mechanisms that must be part of the engine management system.

[0008] Hydrogen has also been suggested as a replacement for fossil fuels for use in internal combustion engines because it is extremely abundant and has a low calorific value comparable to gasoline or diesel. Hydrogen has a high flame speed and low ignition temperature, ignites easily and is known to burn about six times faster than gasoline. Most importantly, hydrogen produces no CO2 emissions when burned.

[0009] However, the challenge of using on-board hydrogen is that hydrogen is an extremely light, low-density gas that cannot be stored as easily as liquid fossil fuels. Hydrogen needs to be compressed, cooled, or a combination of both. Using compressed hydrogen fuel tanks on vehicles itself leads to a series of safety issues, such as the risk of potential failure of the pressure vessel and hydrogen leaks in confined spaces.

[0010] It is well known that hydrogen can be obtained from the catalytic decomposition of ammonia into its hydrogen and nitrogen components through a process known as "cracking". However, the cracking process of ammonia is an endothermic process that requires heat. Due to the limited supply of electricity on motor vehicles, it is difficult to generate the heat required for efficient on-board ammonia cracking.

[0011] Therefore, there is a need for systems and methods for generating hydrogen from on-board ammonia for use as a fuel source for internal combustion engines that address the above-mentioned challenges and shortcomings faced by electrified vehicles, ammonia-fueled internal combustion engines, and on-board hydrogen storage for hydrogen-fueled internal combustion engines. Summary of the invention

[0012] In one embodiment, the present invention relates to an on-vehicle ammonia cracking system for an internal combustion engine, comprising: an ammonia tank filled with liquid ammonia; a heat exchange catalyst unit fluidly connected to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine; and an electrocatalyst unit fluidly connected in series to the heat exchange catalyst unit, wherein gaseous ammonia flows from the ammonia tank to the heat exchange catalyst unit after the liquid ammonia is vaporized, wherein if the exhaust gas reaches a temperature sufficient for ammonia cracking, the gaseous ammonia undergoes a cracking process in the heat exchange catalyst unit, and wherein if the exhaust gas does not reach a temperature sufficient for ammonia cracking, the gaseous ammonia flows out of the heat exchange catalyst unit and flows to the electrocatalyst unit and undergoes a cracking process in the electrocatalyst unit.

[0013] In another embodiment, the present invention relates to an on-vehicle ammonia cracking system for an internal combustion engine, comprising: an ammonia tank filled with ammonia; a heat exchange catalyst unit fluidly connected to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine and receives ammonia from the ammonia tank; and an electrocatalyst unit fluidly connected in series to the heat exchange catalyst unit, the electrocatalyst unit comprising an electric heater, wherein if the exhaust gas reaches a temperature sufficient for ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit, wherein if the exhaust gas does not reach a temperature sufficient for ammonia cracking, the ammonia flows out of the heat exchange catalyst unit and flows to the electrocatalyst unit and undergoes a cracking process in the electrocatalyst unit; and wherein hydrogen generated from the cracking process flows to the internal combustion engine.

[0014] In yet another embodiment, the present invention relates to an on-vehicle ammonia cracking system for an internal combustion engine, comprising: an ammonia tank filled with ammonia; a heat exchange catalyst unit fluidly connected to the ammonia tank, wherein the heat exchange catalyst unit receives exhaust gas from the internal combustion engine and receives ammonia from the ammonia tank; and an electrocatalyst unit fluidly connected in series to the heat exchange catalyst unit, the electrocatalyst unit being powered by a vehicle power system, wherein if the exhaust gas reaches a temperature sufficient for ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit; and if the exhaust gas does not reach a temperature sufficient for ammonia cracking, then: (1) the ammonia is preheated in the heat exchange catalyst unit, (2) the preheated ammonia flows out of the heat exchange catalyst unit and flows to the electrocatalyst unit, and (3) the preheated ammonia undergoes a cracking process in the electrocatalyst unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] These and other embodiments of the present invention will be discussed with reference to the following exemplary and non-limiting illustrations, in which like elements are numbered alike and in which:

[0016] Figure 1 is a perspective internal view of an exchange catalyst unit using a TPMS structure;

[0017] Figure 2 is a perspective interior view of a heat exchange catalyst unit in a TPMS configuration depicting heated exhaust gas and gaseous ammonia flowing through a substrate;

[0018] Figure 3 is a perspective view of a substrate having a spiral TPMS structure;

[0019] Figure 4 is a perspective view of a substrate having an orthogonal hole TPMS structure;

[0020] Figure 5 is a perspective view of a substrate having a split-bean TPMS structure;

[0021] Figure 6is a top perspective view of a heat exchange catalyst unit using a TPMS structure;

[0022] Figure 7 is a front cross-sectional view of a cylindrical heat exchange catalyst unit adopting a TPMS structure;

[0023] Figure 8 is a front cross-sectional view of a cylindrical heat exchange catalyst unit in a TPMS configuration, depicting heated exhaust gas and gaseous ammonia flowing through a substrate;

[0024] Fig. 9 is a side cross-sectional view of a cylindrical heat exchange catalyst unit in a TPMS configuration depicting heated exhaust gas and gaseous ammonia flowing through a substrate;

[0025] Fig.10 is a perspective view of a heat exchange catalyst unit adopting a tube bundle structure;

[0026] Fig.11 is a front cross-sectional view of a heat exchange catalyst unit adopting a tube bundle structure;

[0027] Fig.12 is a side cross-sectional view of a heat exchange catalyst unit adopting a tube bundle structure;

[0028] Fig.13 is a front cross-sectional view of a double-channel heat exchange catalyst unit adopting a tube bundle structure;

[0029] Fig.14 is a block diagram of an on-board ammonia cracking system for an internal combustion engine; and

[0030] Fig.15 is a perspective view of an on-board ammonia cracking system for an internal combustion engine;

[0031] Fig.16 It is a top-down perspective view of the vehicle-mounted ammonia cracking system;

[0032] Fig.17 is a perspective side view of a vehicle-mounted ammonia cracking system;

[0033] Fig.18 is a perspective view of an electrocatalyst unit; and

[0034] Fig.19 is a cross-sectional view of an electrocatalyst unit.

[0035] definition

[0036] The following definitions are intended to help describe and understand the terms defined in this invention. These definitions are not meant to limit these terms to the scope described in this specification. These definitions are intended to include grammatical equivalents.

[0037] As used herein, the term "motor vehicle" means any moving vehicle capable of carrying one or more passengers and / or cargo, or capable of performing a task, and driven 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 cars, freight cars, two-wheeled, three-wheeled and four-wheeled automobiles, quadricycles, motorcycles, scooters, all-terrain vehicles, multi-purpose task vehicles, etc.; (b) aerial vehicles, such as helicopters, airplanes, airships, drones, aerospace vehicles, etc.; (c) marine vessels, such as dry cargo ships, liquid cargo ships, special cargo ships, tugboats, cruise ships, recreational boats, fishing boats, personal watercraft, jet skis, etc.; (d) locomotives; and (e) heavy equipment and machinery, generators, lawn mowers and tractors, agricultural equipment and machinery, forestry equipment and machinery, construction equipment and machinery, mining equipment and machinery, etc.

[0038] 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 occurs in a combustion chamber so that the products of combustion, together with any other by-products, perform work by applying forces to moving surfaces, which results in a mechanical output from 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.

[0039] 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 that can promote a cracking reaction (such as an ammonia cracking reaction), whether used as a base catalyst and / or an added catalyst. For the present invention, the catalyst may include, but is not limited to, non-stoichiometric lithium imide, nickel, iron, cobalt, iron cobalt, ruthenium, vanadium, palladium, rhodium, platinum, sodium amide, etc., and various combinations thereof.

[0040] As used herein, the term "cracking" refers to one or more processes in which ammonia is decomposed into its hydrogen and nitrogen components over at least one catalyst.

[0041] As used herein, the term "nickel alloy" refers to pure nickel or an alloy with nickel as the main component. The term "nickel alloy" includes but is not limited to And other compound metals with nickel as the main component. is a trademark of Special Metals Corporation of Huntington, West Virginia.

[0042] As used herein, the term "triperiodic minimal surface (TPMS)" refers to a mathematically defined structure that repeats in three dimensions with zero mean curvature and a large surface area. DETAILED DESCRIPTION

[0043] It should be understood that various aspects of the invention are described herein with reference to the accompanying drawings, which show illustrative embodiments. The illustrative embodiments herein are not necessarily intended to show all embodiments according to the invention, but are used to describe some illustrative embodiments. Therefore, various aspects of the invention are not intended to be narrowly interpreted in terms of the illustrative embodiments. In addition, although the invention is described with respect to its application to an internal combustion engine of a motor vehicle, it is understood that the system can be implemented in any engine drive arrangement that can be driven by ammonia and / or hydrogen fuel.

[0044] Figure 1 1 is a perspective internal view of a heat exchange catalyst unit in a TPMS configuration and which functions as both a heat exchanger and a catalytic converter for ammonia cracking. The heat exchange catalyst unit 100 is metallic 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 Made.

[0045] 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 of the same metal 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 of stainless steel, silver, bronze, and similar alloys.

[0046] Located between the inlets 102, 106 and the outlets 104, 108 is a substrate 110. The substrate 110 is formed by a transverse surface 112 and a longitudinal surface 114, which are generally perpendicular to each other. The surfaces 112 and 114 of the substrate 110 form passages that allow gaseous ammonia and heated exhaust gas to flow therethrough; these passages are represented by ammonia conduits 116 and heated exhaust conduits 118. Gaseous ammonia is supplied to the heat exchange catalyst unit 100 through the inlet 102, while heated exhaust gas is also supplied to the inlet 106. Gaseous ammonia passes through the substrate 110 through the ammonia conduit 116, while heated exhaust gas passes through the substrate through the heated exhaust conduit 118. The directions of the ammonia conduit 116 and the heated exhaust conduit 118 are generally perpendicular to each other, so that the gaseous ammonia passes through the substrate 110 at approximately right angles to the heated exhaust gas.

[0047] In one embodiment, the thickness of the surfaces 112, 114 is 1 to 2 millimeters, and each surface 112, 114 can have the same thickness. In another embodiment, the surfaces 112, 114 can each have a different thickness. In yet another embodiment, the thickness of the surfaces 112, 114 can be different when each passes through the substrate 110. For example, the surfaces 112, 114 may not have a uniform thickness across the width of the substrate 110, and may have thicker or narrower portions at different locations.

[0048] like Figure 1 As shown, the substrate 110 physically separates the gases passing through each conduit 116, 118, thereby providing a particularly large surface area throughout the substrate 110 where the heated exhaust gas exchanges heat with the gaseous ammonia. In one embodiment, the surfaces 112, 114 of the substrate 110 are coated with a catalyst that promotes the cracking of ammonia into its hydrogen and nitrogen components. In this embodiment, the surfaces 112, 114 of the substrate 110 are coated with the catalyst using a wash coating or deposition technique to bond or adhere the catalyst to the surfaces 112, 114.

[0049] In another embodiment, catalyst in the form of discrete catalyst media is deposited into the channels forming the ammonia conduit 116 and the heated exhaust conduit 118. The discrete catalyst media may be porous, allowing the gaseous ammonia and exhaust gas to pass through the catalyst as they each flow through the substrate 110.

[0050] In yet another embodiment, the surfaces 112 , 114 of the substrate 110 may be coated with the catalyst described herein, and additional discrete catalyst media may be deposited into the channels forming the ammonia conduit 116 and the heated exhaust conduit 118 .

[0051] In one embodiment, the substrate 110 is metallic and made of a nickel alloy. In a preferred embodiment, the substrate 110 is made of The heat exchange catalyst unit 100 and the substrate 110 may be made of the same metal material. In another embodiment, the heat exchange catalyst unit 100 and the substrate 110 may be made of different metal materials.

[0052] The materials selected for the heat exchange catalyst unit 100 and the substrate 110 need to be able to withstand the corrosive environment caused by the high temperature heated exhaust gas and the heated hydrogen generated by the cracking of ammonia.

[0053] In a preferred embodiment, the substrate 110 is in the form of a three-periodic minimal surface (TPMS), and the substrate 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 powdered metal particles together to form a TPMS structure in a layer-by-layer manner. The TPMS structure of the substrate 110 provides a relatively large surface area, including a small chamber that can be confined within the size and shape of the heat exchange catalyst unit 100.

[0054] The TPMS structure can adopt various crystal-like structures with different patterns and contours. Figure 1 In the embodiment shown, the TPMS is a spiral structure. These structures can be in various forms such as, but not limited to, spiral, diamond, orthogonal holes, split beans, etc. Each form has a different surface area. For example, in Figure 1 In the illustrated embodiment, the dimensions of the heat exchange catalyst unit 100 are approximately 10 x 10 x 4 inches. For a substrate 110 meeting these dimensions, Table 1 provides approximate surface area values ​​for various TPMS structures that may be used:

[0055] structure <![CDATA[Surface area (million mm 2 )]]> spiral <![CDATA[1.5 million millimeters 2 > Orthogonal holes <![CDATA[1.6 million millimeters 2 > cracked beans <![CDATA[2.1 million millimeters 2 > diamond <![CDATA[2.5 million millimeters 2 >

[0056] Table 1

[0057] However, it should be noted that the values ​​in Table 1 are only illustrative examples and are not intended to be limiting. The size of a single chamber of the TPMS can be changed to increase or decrease the surface area of ​​the substrate 110. For example, within the same volume of the heat exchange catalyst unit 100, the size of a single chamber can be increased to increase the total surface area of ​​the substrate 110, and conversely, the size of a single chamber can be reduced to reduce the total surface area of ​​the substrate 110.

[0058] The TPMS structure is an ideal structure for the substrate 110 because it allows heat to be distributed to all surfaces of the substrate 100, thereby promoting the chemical reactions required for the ammonia cracking process. As the surface area of ​​the substrate 110 increases, cleaning the surface of the substrate 110 after printing faces inherent challenges because as the surface area increases, the formed conduits 116, 118 become narrower relative to each other. However, as the size of the cells of the substrate 110 increases, the surface area decreases, which reduces the throughput efficiency of the heat exchange catalyst unit 100. The surface area of ​​the substrate 110 may depend on the power requirements of the vehicle and its engine.

[0059] In one embodiment, the size and dimensions of the heat exchange catalyst unit 100 can accommodate a substrate 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, between 5 to 30 inches in length, and between 0.5 to 12 inches in height.

[0060] In one embodiment, the heat exchange catalyst unit 100 has a generally square shape, which can accommodate a square substrate 110, such as Figure 1 , which are merely illustrative examples and are not intended to be limiting in any way. In other embodiments, the heat exchange catalyst unit 100 can be any polygonal shape, such as, for example, an ellipse, rectangle, triangle, square, kite, trapezoid, parallelogram, rhombus, etc., and various 3D shapes, such as, for example, a cube, cuboid, sphere, cone, etc.

[0061] In one embodiment, the diameter of the ammonia inlet 102 is smaller than the diameter of the heated exhaust gas inlet 106 because the exhaust gas flow rate can be several orders of magnitude higher than the ammonia flow rate. As with the size of the heat exchange catalyst unit 100, the diameter, shape and size of the inlets 102, 106 and outlets 104, 108 can vary depending on the power requirements of the vehicle and its engine.

[0062] Figure 2 1 is a perspective internal view of a heat exchange catalyst unit 100 in a TPMS configuration, depicting heated exhaust gas and gaseous ammonia flowing through the substrate. In operation, gaseous ammonia 200 is supplied to inlet 102 and flows through ammonia conduit 116, while heated exhaust gas 202 is supplied to inlet 106 and flows through heated gas conduit 118. The heated exhaust gas 202 heats the catalyst, causing the gaseous ammonia 200 to crack into hydrogen and nitrogen components 204. The resulting hydrogen and nitrogen components 204 flow out of the heat exchange catalyst unit 100 through outlet 104 and are supplied to the downstream injection system of the engine, while residual exhaust gas 206 flows out of the heat exchange catalyst unit through outlet 108.

[0063] Figure 3is a perspective view of a substrate 110 having a spiral TPMS structure, Figure 4 is a perspective view of a substrate 110 having an orthogonal hole TPMS structure, and Figure 5 is a perspective view of the substrate 110 having a split bean TPMS structure. However, it should be noted that Figures 1 to 5 The TPMS structures described in are merely illustrative examples and are not intended to be limiting in any way.

[0064] Figure 6 1 is a top perspective view of a heat exchange catalyst unit 100 in a TPMS structure. In one embodiment, the heat exchange catalyst unit 100 can be manufactured by welding the inlet 102, 106 and the outlet 104, 108 to the housing 600. In one embodiment, the housing 600 can include a cover ( Figure 6 104, 108 can be removably connected to the housing 600 so that different inlets and outlets having different sizes, dimensions, and flow characteristics can be used with the housing 600 in a modular manner.

[0065] Figure 7 FIG. 7 is a front cross-sectional view of a cylindrical heat exchange catalyst unit 700 adopting a TPMS structure. Figure 1 Similar to the heat exchange catalyst unit 100 shown in FIG. 1 , the cylindrical heat exchange catalyst unit 700 is metal and made of a nickel alloy, and in a preferred embodiment, the cylindrical heat exchange catalyst unit 700 is made of Made.

[0066] In one embodiment, the cylindrical heat exchange catalyst unit 700 includes an ammonia inlet 702, a hydrogen outlet 704, a heated exhaust inlet 706, and an exhaust outlet 708. Located between the inlets 702, 706 and the outlets 704, 708 is a substrate 710. The substrate 710 is composed of a transverse surface 712 and a longitudinal surface 714, which are generally perpendicular to each other. The surfaces 712 and 714 of the substrate 710 form channels that allow the flow of gaseous ammonia and heated exhaust; these channels are represented by ammonia conduits 716 and heated exhaust conduits 718.

[0067] Gaseous ammonia is supplied to the cylindrical heat exchange catalyst unit 700 through inlet 702, while heated exhaust gases are supplied to inlet 706. The gaseous ammonia passes through the substrate 710 in an axial direction, while the heated exhaust gases pass through the substrate laterally.

[0068] like Figure 7As shown, the substrate 710 physically separates the gases passing through each conduit 716, 718, thereby providing a particularly large surface area throughout the substrate 710 where the heated exhaust gas exchanges heat with the gaseous ammonia. In one embodiment, the surfaces 712, 714 of the substrate 710 are coated with a catalyst that promotes the cracking of ammonia into its hydrogen and nitrogen components. In this embodiment, the surfaces 712, 714 of the substrate 710 are coated with the catalyst using a wash coating or deposition technique to bond or adhere the catalyst to the surfaces 712, 714.

[0069] In another embodiment, the catalyst in the form of discrete catalyst media is deposited into the channels forming the ammonia conduit 716 and the heated exhaust conduit 718 .

[0070] In yet another embodiment, surfaces 712 , 714 of substrate 710 may be coated with a catalyst as described herein, and additional discrete catalyst media may be deposited into channels forming ammonia conduit 716 and heated exhaust conduit 718 .

[0071] Figure 8 7 is a front cross-sectional view of a cylindrical heat exchange catalyst unit 700 in a TPMS configuration, depicting heated exhaust gas and gaseous ammonia flowing through the substrate. In operation, gaseous ammonia 200 is supplied to inlet 702 and flows through ammonia conduit 716, while heated exhaust gas 202 is supplied to inlet 706 and flows through heated gas conduit 718. The heated exhaust gas 202 heats the catalyst, causing the ammonia 200 to crack into hydrogen and nitrogen components 204. The resulting hydrogen and nitrogen components 204 flow out of the heat exchange catalyst unit 700 through outlet 704 and are supplied to the downstream injection system of the engine, while residual exhaust gas 206 flows out of the heat exchange catalyst unit through outlet 708.

[0072] Fig. 9 FIG. 7 is a side cross-sectional view of a cylindrical heat exchange catalyst unit 700 in a TPMS configuration, depicting heated exhaust gas and gaseous ammonia flowing through the substrate. Fig. 9 As shown, surfaces 712, 714 of substrate 710 create ammonia conduits 716 and heated exhaust conduits 718. The cylindrical design provides efficiencies in mass production due to its rounded shape, fewer welds / joints than square and rectangular designs, and less susceptible to thermal stress.

[0073] 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 other way. In other embodiments, the heat exchange catalyst unit 700 can be any polygonal shape, such as, for example, an ellipse, a rectangle, a triangle, a square, a kite, a trapezoid, a parallelogram, a rhombus, etc., and various 3D shapes, such as, for example, a cube, a cuboid, a sphere, a cone, etc.

[0074] Fig.10 1 is a perspective view of a heat exchange catalyst unit 1000 that uses a tube bundle structure and acts as both a heat exchanger and a catalytic converter for ammonia cracking. The heat exchange catalyst unit 1000 is metal and, in one embodiment, includes a side wall 1002 that includes a gaseous ammonia inlet 1004. In one embodiment, the inlet side wall 1002 may include an additional port 1006 that may be used for a variety of functions. For example, the port 1006 may be used as an inlet and may also be connected to a device for sensing temperature, throughput, and / or pressure.

[0075] 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 plate 1010, which evenly spreads the heated exhaust gas from the engine to the internal tube bundle structure contained in the heat exchange catalyst unit 1000, as shown in FIG. Fig.11 In one embodiment, the separator plate 1010 may have a grid or lattice structure.

[0076] The heat exchange catalyst unit 1000 includes an exhaust gas outlet 1012 positioned opposite the heated gas inlet 1008 .

[0077] Fig.11 1 is a front cross-sectional view of a heat exchange catalyst unit 1000 with a tube bundle structure. In one embodiment, the tube bundle structure 1100 is disposed in the heat exchange catalyst unit 1000. The tube bundle structure 1100 is composed of individual tubes 1102, which extend perpendicularly to the inlet 1008 and the outlet 1012 along the width of the heat exchange catalyst unit 1000 starting from the side wall 1002.

[0078] 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 their adjacent tubes. This pattern can maximize the surface area that is contacted by the heated exhaust gas as the gas passes through the tube bundle structure 1100, thereby maximizing the amount of heating of the catalyst to promote the cracking process.

[0079] 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 operation of the heat exchange catalyst unit 1000 .

[0080] Gaseous ammonia is supplied to the heat exchange catalyst unit 1000 through inlet 1004, while heated exhaust gas is supplied to inlet 1008. The gaseous ammonia passes through the lateral spaces between the tubes 1102, while the heated exhaust gas passes through the axial spaces inside the tubes 1102.

[0081] In one embodiment, the spaces between the tubes 1102 are filled with catalyst in the form of discrete catalyst media. In another embodiment, the tubes 1102 themselves are hollow and are also filled with discrete catalyst media.

[0082] In yet another embodiment, the outer and / or inner surfaces of the tube 1102 are also coated with the catalyst using a wash coating or deposition technique to bind or adhere the catalyst to the surface.

[0083] Fig.12 1 is a side cross-sectional view of a heat exchange catalyst unit 1000 using a tube bundle structure 1100. In one embodiment, the heat exchange catalyst unit 1000 includes a side wall 1200 disposed opposite to the side wall 1002. The side wall 1200 includes a hydrogen outlet 1202 and may include additional ports 1204 that may be used for various functions. For example, the port 1204 may be used as an outlet and may also be connected to temperature, throughput and / or pressure sensing equipment.

[0084] In operation, gaseous ammonia is supplied to inlet 1004, while heated exhaust gas is supplied to inlet 1008. The heated exhaust gas heats the catalyst, causing the ammonia to crack into hydrogen and nitrogen components. The resulting hydrogen and nitrogen components flow out of the heat exchange catalyst unit 1000 through outlet 1202 and are supplied to the downstream engine.

[0085] In one embodiment, the heat exchange catalyst unit 1000 is made of nickel alloy. In a preferred embodiment, the heat exchange catalyst unit 1000 is made of Made.

[0086] 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 plate 1010, the exhaust gas outlet 1012, and the support structure 1104 can be made of the same metal material as the heat exchange catalyst unit 1000. In another embodiment, the side walls 1002, 1200, the gaseous ammonia inlet 1004, the partition plate 1010, the hydrogen outlet 1202, the heated exhaust gas inlet 1008, and the exhaust gas outlet 1012 can be made of stainless steel, silver, bronze, and similar alloys.

[0087] Fig.13 1 is a front cross-sectional view of a dual-channel heat exchange catalyst unit 1300 using a tube bundle structure 1100. In this embodiment, the support structure 1302 includes a receiving side wall ( Fig.13The support structure 1302 includes a partition plate 1304, which physically divides the tube bundle structure 1100 into a left section 1306 and a right section 1308. The partition plate 1304 extends between the two side walls along the width of the dual-channel heat exchange catalyst unit 1300. In this embodiment, the gaseous ammonia inlet is placed on the side wall covering the left section 1306, and the hydrogen outlet is placed on the side wall covering the right section 1308.

[0088] In operation, gaseous ammonia is supplied to the gaseous ammonia inlet, while heated exhaust gas is supplied to the inlet 1008. As the ammonia passes through the left section 1306 of the tube bundle structure 1100, the heated exhaust gas heats the catalyst, causing the ammonia to crack into hydrogen and nitrogen components. The remaining ammonia flows back from the right section 1308 of the tube bundle structure 1100 and continues to crack, thereby achieving a dual-channel cracking process. The resulting hydrogen and nitrogen components exit the dual-channel heat exchange catalyst unit 1300 through the hydrogen outlet and are supplied to the downstream engine.

[0089] Fig.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 to produce hydrogen from ammonia without the need to carry a separate hydrogen tank in the motor vehicle.

[0090] Reference Fig.14 , ammonia tank 1402 is mounted to a motor vehicle or engine, and in one embodiment, ammonia tank 1402 may be coupled to pump 1404. In one embodiment, tank 1402 is refillable and / or replaceable. Pump 1404 may be coupled to a port on tank 1402 to deliver ammonia from tank 1402. For example, in a cold environment with a temperature of about 0°C or less, the vapor pressure of ammonia is insufficient to push itself out of tank 1402. Therefore, pump 1404 is required to extract or force ammonia out of tank 1402.

[0091] In another embodiment, the electric heater ( Fig.14 1402, such as within the tank 1402 or on an outer surface of the tank 1402, so as to heat the liquid ammonia contained in the tank 1402 to a temperature at which it vaporizes into a gaseous form.

[0092] In one embodiment, a pressure regulator 1406 is coupled to the outlet of the tank 1402 and is used to control the volume and / or flow rate of ammonia drawn from the tank 1402 by the pump 1404. The pressure regulator 1406 monitors the pressure of the liquid ammonia in the tank 1402. Once the pressure drops to a critical pressure value at which the liquid ammonia can be vaporized into a gaseous form, the pressure regulator 1406 opens and delivers gaseous ammonia downstream. Any residual liquid ammonia passing through the pressure regulator 1406 is sent to the injection system 1408 (e.g., through a T-joint on the supply line).

[0093] In one embodiment, the temperature control valve 1410 receives a temperature feedback signal 1412 that includes a temperature reading from the electrocatalyst unit 1420 during a cold start of the engine. The temperature feedback signal 1412 may be generated by a temperature sensor coupled to the electrocatalyst unit 1420. Once the electrocatalyst unit 1420 reaches a threshold temperature suitable for performing an ammonia cracking process (i.e., a temperature reading equal to or greater than the threshold temperature), the temperature control valve 1410 opens, and gaseous ammonia passes through the heat exchange catalyst unit 1418 and flows downstream to the electrocatalyst unit 1420, which is heated using power provided by the vehicle power system 1422.

[0094] If the electrocatalyst unit 1420 has not reached the threshold temperature, the temperature control valve 1410 continues to monitor the temperature feedback signal 1412 and prevents the gaseous ammonia from moving downstream. Cold start operation will be described in more detail herein.

[0095] In one embodiment, the temperature of the heated exhaust gas entering the heat exchange catalyst unit 1418 is determined based on the current draw in the electrocatalyst unit 1420, where the current draw indicates how effectively the heat exchange catalyst unit 1418 is cracking the gaseous ammonia.

[0096] For example, if hydrogen and nitrogen are entering the electrocatalyst unit 1420 from the heat exchange catalyst unit 1418, the electrocatalyst unit 1420 will not perform the ammonia cracking process and will therefore consume minimal or no current.

[0097] However, if gaseous ammonia enters the electrocatalyst unit 1420 from the heat exchange catalyst unit 1418 , an ammonia cracking process may occur, thereby consuming current to heat a heating element disposed in the electrocatalyst unit 1420 .

[0098] However, during normal or high load operation of the engine (i.e., not during cold start or low load operation), the on-board ammonia cracking system 1400 does not use the electrocatalyst unit 1420 to perform the ammonia cracking process, but instead the heat exchange catalyst unit 1418 performs the ammonia cracking process because it has been heated to a threshold temperature by the heated exhaust gas from the engine.

[0099] Fig.14 The heat exchange catalyst unit 1418 mentioned in the specification can be any one of the embodiments described in this article - a heat exchange catalyst unit 100 with a TPMS structure, a cylindrical heat exchange catalyst unit 700 with a TPMS structure, a heat exchange catalyst unit 1000 with a tube bundle structure, or a dual-channel heat exchange catalyst unit 1300 with a tube bundle structure.

[0100] The pressure control valve 1414 is connected in series with the temperature control valve 1410 and controls the amount of gaseous ammonia entering the heat exchange catalyst unit 1418 .

[0101] 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 sensor or similar unit ( Fig.14 not depicted).

[0102] In one embodiment, when the exhaust gas discharged by the engine does not reach a threshold temperature suitable for the ammonia cracking process, in order to facilitate the cold start of the on-board ammonia cracking system 1400, the electrocatalyst unit 1420 is used to heat the catalyst so that the gaseous ammonia can be cracked and the generated hydrogen is supplied to the downstream injection system of the engine. The engine can then burn the hydrogen to provide power for the engine, which will generate heated exhaust gas supplied to the on-board ammonia cracking system 1400.

[0103] In one embodiment, the electrocatalyst unit 1420 is coupled to a vehicle powertrain 1422, such as a conventional vehicle battery. In another embodiment, the electrocatalyst unit 1420 may be heated by a supplemental heating / electric power source, such as a renewable energy source, a portable battery source, an onboard electric battery pack, and / or a rechargeable battery.

[0104] In addition to facilitating cold starts of the on-board ammonia cracking system 1400, the electrocatalyst unit 1420 can also be used to supplement the heat exchange catalyst unit 1418 during low-load operation of the engine, such as when the vehicle is stopped, moving slowly, or idling. For example, during low-load operation, the engine exhaust temperature can drop significantly. During such low-load operation, the temperature of the exhaust gas flowing into the heat exchange catalyst unit 1418 decreases and may not be sufficient for the catalyst to crack ammonia. In one embodiment, depending on the specific catalyst used, the temperature of the exhaust gas needs to be at least between 400°C and 700°C in order to proceed with the ammonia cracking process, and in a preferred embodiment, the temperature of the exhaust gas is at least 600°C in order to proceed with the ammonia cracking process.

[0105] In this case, the cold gaseous ammonia will pass through the heat exchange catalyst unit 1418 and will be supplied to the downstream electrocatalyst unit 1420, which is heated using power supplied by the vehicle power system 1422. Once the electrocatalyst unit 1420 is heated to a threshold temperature suitable for the ammonia cracking process, the temperature control valve 1410 will open and allow the gaseous ammonia to enter the heat exchange catalyst unit 1418 and ultimately enter the electrocatalyst unit 1420. The electrocatalyst unit 1420 then performs the ammonia cracking process and supplies the generated hydrogen to the downstream injection system of the engine.

[0106] When the exhaust gas flowing into the heat exchange catalyst unit 1418 reaches a threshold temperature suitable for the ammonia cracking process, such as during normal or high load operation of the engine, the ammonia cracking process occurs in the heat exchange catalyst unit 1418. The hydrogen and nitrogen produced thereby will enter downstream through the electrocatalyst unit 1420 and further enter the gas-liquid or gas-gas heat exchange unit 1428, and then enter the engine's injection system 1430. In one embodiment, the gas-liquid or gas-gas heat exchange unit 1428 can utilize engine coolant and / or engine radiator, or input ammonia gas or ammonia liquid to facilitate the heat exchange process.

[0107] In one embodiment, the pressure regulator 1406 may be controlled by an electric servo motor to provide a steady flow of gaseous ammonia from the 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 ( Fig.14 not depicted).

[0108] In one embodiment, the electronic controller can be coupled to various components of the onboard ammonia cracking system 1400 to receive inputs from the pressure regulator 1406, the temperature control valve 1410, the pressure control valve 1414, and sensors such as temperature sensors and pressure sensors that can be coupled to the heat exchange catalyst unit 1418 and / or the electrocatalyst unit 1420.

[0109] In another embodiment, the electronic controller may be integrated into hardware and software with the vehicle's electronic control unit (ECU). In this embodiment, the flow rate of hydrogen fed to the engine injection system may be measured and fed back to the ECU as a mechanism to control the injection strategy.

[0110] Figure 15-17 yes Fig.14 Various perspective views of an onboard ammonia cracking system 1400 for an internal combustion engine.

[0111] Fig.18 18 is a perspective view of an electrocatalyst unit. In one embodiment, the electrocatalyst unit 1800 includes a housing 1802 that surrounds a ceramic tube 1900 ( Fig.19 In one embodiment, housing 1802 is a metal housing.

[0112] In one embodiment, the electrocatalyst unit 1800 includes a gaseous ammonia inlet 1804 and a hydrogen outlet 1806 disposed at the other end of the electrocatalyst unit 1800. The electrocatalyst unit further includes power feedthroughs 1808, 1810 (eg, Fig.19). In one embodiment, the electrocatalyst unit 1800 may include radial fittings 1812, 1814, which may be used for a variety of functions. For example, the radial fittings 1812, 1814 may be used as inlets, outlets, and may also be coupled to temperature, throughput, and / or pressure sensing devices. In one embodiment, the radial fittings 1812 may each include a thermocouple, or be coupled to a thermocouple, and the radial fittings 1814 may include a pressure sensor, or be coupled to a pressure sensor.

[0113] Fig.19 is a cross-sectional view of an electrocatalyst unit 1800. In one embodiment, a ceramic tube 1900 houses the catalyst. The ceramic tube 1900 acts as an insulator and allows heat to be focused and reflected to the catalyst, thereby heating the catalyst.

[0114] In one embodiment, the first filter screen 1901 and the second filter screen 1902 are disposed at opposite ends of the ceramic tube 1900. The filter screens 1901 and 1902 may be made of metal wires, metal meshes, or other metal meshes or matrix structures. In one embodiment, the filter screens 1901 and 1902 may be made of a nickel alloy that can withstand the heated hydrogen produced by the cracking of ammonia, as well as the gaseous ammonia itself.

[0115] In one embodiment, a heating element 1904 is also disposed within the ceramic tube 1900. An electric current is passed through the heating element 1904 so as to heat the heating element 1904 to a threshold temperature suitable for the ammonia cracking process. In one embodiment, the heating element 1904 and the filter screens 1901, 1902 are made of a nickel alloy or other material resistant to hydrogen and ammonia, because nickel can maintain a fairly constant resistance at high temperatures, while steel has a lower resistance at high temperatures. In addition, the nickel alloy may have a higher corrosion resistance when exposed to ammonia and hydrogen at high temperatures (which may be implemented in the electrocatalyst unit 1800, such as, for example, when the temperature exceeds 600°C).

[0116] In a preferred embodiment, the heating element 1904 and the filters 1901, 1902 are composed of In one embodiment, the heating element 1904 and the filters 1901 and 1902 may be made of the same material. Alternatively, the heating element 1904 and the filters 1901 and 1902 may be made of different materials.

[0117] In one embodiment, the heating element 1904 can be an air handling heater, a cartridge heater, a tubular heater, a belt heater, a strip heater, an etched foil heater (or thin film heater), a ceramic heater, a ceramic fiber heater, a resistance wire, or the like.

[0118] In one embodiment, each end of the heating element 1904 is in contact with a power feedthrough 1808, 1810. The power feedthrough 1808, 1810 provides power or heat to the heating element 1904.

[0119] In one embodiment, the heating element 1904 is regulated by an electronic controller coupled to power feedthroughs 1808, 1810 using the reading of a thermocouple coupled to radial fitting 1812 so that the heating element 1904 maintains a threshold temperature suitable for 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.

[0120] In one embodiment, an electronic controller may be used to control an electric expansion valve (EVV) coupled to inlet 1804 by utilizing readings from a pressure sensor coupled to radial fitting 1814 and / or a thermocouple coupled to radial fitting 1812. Fig.19 Once the gaseous ammonia received by the electrocatalyst unit 1800 from the heat exchange catalyst unit reaches a threshold temperature, an electric expansion valve is used to maintain the vapor pressure of the gaseous ammonia. At these threshold temperature and pressure values, the electric expansion valve is opened to allow ammonia gas to enter the ceramic tube 1900.

[0121] In one embodiment, the catalyst (eg, discrete catalyst media) is deposited into the ceramic tube. The gaseous ammonia reacts with the catalyst in the ceramic tube 1900, and the generated hydrogen and nitrogen components flow out of the electrocatalyst unit 1800 through the outlet 1806 and are supplied to the downstream injection system of the engine.

[0122] In another embodiment, the heating element 1904 is coated with a catalyst that promotes the ammonia cracking process, and the discrete catalyst is not disposed within the ceramic tube 1900. In this embodiment, the catalyst is applied to the heating element 1904 using a wash coating or deposition technique to bond or adhere the catalyst to the surface of the heating element 1904.

[0123] In one embodiment, the heating element 1904 is a strip heater. The catalyst may be coated on all surfaces of the heating element 1904, or a catalyst sleeve may be optionally placed on the strip heating element 1904. In one embodiment, the strip heating element 1904 may have a relatively low heat transfer efficiency so that the catalyst coating the strip heating element 1904 on the outside maintains a high skin (or boundary layer) temperature.

[0124] In another embodiment, the heating element 1904 is a spiral heater, coil heater, or air handling heater where the inner wall (which contains the integral heating element) is coated with a catalyst.

[0125] 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 to bond or adhere the catalyst to the wall surface.

[0126] The remaining figures have been provided to show additional details and embodiments of the airborne ammonia cracking system.

[0127] Although the principles of the present disclosure have been described in conjunction with the exemplary embodiments shown herein, the principles of the present disclosure are not limited thereto but also include any modifications, variations, or permutations thereof.

Claims

1. A vehicle-mounted ammonia cracking system 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 electrocatalyst unit fluidly connected in series with the heat exchange catalyst unit, wherein gaseous ammonia flows from the ammonia tank to the heat exchange catalyst unit after the liquid ammonia is vaporized, wherein if the exhaust gas reaches a temperature sufficient for ammonia cracking, the gaseous ammonia undergoes a cracking process in the heat exchange catalyst unit, and If the exhaust gas does not reach a temperature sufficient for ammonia cracking, the gaseous ammonia flows out of the heat exchange catalyst unit and flows to the electrocatalyst unit, and the cracking process is performed in the electrocatalyst unit.

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

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

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

5. The system of claim 4, wherein a surface of the substrate is coated with a catalyst. 6 . The system of claim 1 , wherein the heat exchange catalyst unit comprises a tube bundle structure including individual tubes extending along a width of the heat exchange catalyst unit perpendicular to an inlet for receiving the exhaust gas.

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

8. An on-vehicle ammonia cracking system 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 ammonia from the ammonia tank; and an electrocatalyst unit fluidly connected in series with the heat exchange catalyst unit, the electrocatalyst unit comprising an electric heater, If the exhaust gas reaches a temperature sufficient for ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit. wherein if the exhaust gas does not reach a temperature sufficient for ammonia cracking, the ammonia flows out of the heat exchange catalyst unit and flows to the electrocatalyst unit, and the cracking process is carried out in the electrocatalyst unit, and The hydrogen produced from the cracking process is fed to the internal combustion engine. 9 . The system according to claim 8 , wherein when the ammonia undergoes the cracking process in the heat exchange catalyst unit, the generated hydrogen and nitrogen flow out of the heat exchange catalyst unit and flow toward the electrocatalyst unit.

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

11. The system of claim 8, wherein the temperature sufficient to crack ammonia ranges from 400°C to 700°C, depending on the specific catalyst disposed in the heat exchange catalyst unit or the electrocatalyst unit.

12. The system of claim 8, wherein the electric heater is selected from the group consisting of an air handling 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 having a series of rows and columns.

14. The system of claim 8, wherein the heat exchange catalyst unit comprises a tube bundle structure including individual tubes extending perpendicularly to an inlet of the exhaust gas along a width of the heat exchange catalyst unit.

15. An on-vehicle ammonia cracking system 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 ammonia from the ammonia tank; and an electrocatalyst unit fluidly connected in series with the heat exchange catalyst unit, the electrocatalyst unit being powered by a vehicle power system, wherein if the exhaust gas reaches a temperature sufficient for ammonia cracking, the ammonia undergoes a cracking process in the heat exchange catalyst unit, and If the off-gas does not reach a temperature sufficient for ammonia cracking: (1) preheating the ammonia in the heat exchange catalyst unit, (2) the preheated ammonia flows out of the heat exchange catalyst unit and flows to the electrocatalyst unit, and (3) The preheated ammonia undergoes the cracking process in the electrocatalyst unit.

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

17. The system of claim 16, wherein the electric heater is selected from the group consisting of an air handling 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. The system of claim 15, wherein the electrocatalyst unit comprises discrete catalyst media deposited within the electrocatalyst unit.

19. The system of claim 15, wherein the temperature sufficient to crack ammonia ranges from 400°C to 700°C, depending on the specific catalyst disposed in the heat exchange catalyst unit or the electrocatalyst unit.

20. The system of claim 15, wherein hydrogen produced from the cracking process flows into the internal combustion engine to be used as an auxiliary fuel for combustion with the ammonia.

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