Ammonia-hydrogen engine based on reforming mechanism

Abstract

The application discloses an ammonia-hydrogen engine based on a reforming mechanism, which comprises an engine controller, an ammonia fuel tank, a fuel pump, a multifunctional ammonia reformer, a throttle valve, a circulating reciprocating internal combustion engine and a controllable flow control device. The ammonia is reformed into hydrogen by the multifunctional ammonia reformer for use, so that the hydrogen enters a premixing chamber through a second valve to be mixed with ammonia to form hydrogen-rich fuel for combustion, thereby overcoming the shortcomings of a pure hydrogen engine, such as insufficient power, and a pure ammonia engine, such as high ignition energy, slow flame propagation speed and difficult ignition. In addition, the hydrogen-rich ratio is calculated based on the current load of the ammonia-hydrogen engine, the target ammonia injection amount and the target hydrogen injection amount are calculated according to the hydrogen-rich ratio and the target hydrogen-ammonia fuel supply amount, so as to realize accurate control of the ammonia injection amount and the hydrogen injection amount, and make the mixed fuel in the circulating reciprocating internal combustion engine more combustible, the flame more stable and the combustion more sufficient.

Description

Technical Field

[0001] This invention relates to the field of reforming technology, and more specifically, to an ammonia-hydrogen engine based on a reforming mechanism. Background Technology

[0002] Ammonia and hydrogen are two zero-carbon fuels that are currently receiving particular attention from academia and industry.

[0003] Hydrogen can be sourced in various ways, such as from renewable energy sources through electrolysis (which is considered green hydrogen) and industrial by-products (which are considered grey hydrogen). Furthermore, hydrogen combustion produces only water and some nitrogen oxides, making it a zero-carbon fuel, thus attracting increasing attention from scholars and companies. Research has found that pure hydrogen engines have high thermal efficiency under lean-burn conditions, but this also leads to a rapid drop in engine power. Studies have shown that for the same internal combustion engine, using hydrogen fuel results in a more than 50% decrease in peak power compared to gasoline fuel.

[0004] Ammonia is an ideal alternative fuel due to its carbon-free nature, and its energy density and storage methods are superior to hydrogen. However, the combustion of pure ammonia requires high ignition energy and has a low combustion rate.

[0005] Therefore, for engines, under pure hydrogen conditions, there is a disadvantage of reduced engine power, while under pure ammonia conditions, there are disadvantages of high ignition energy, slow flame propagation speed, and difficulty in ignition. Summary of the Invention

[0006] This invention provides an ammonia-hydrogen engine based on a reforming mechanism, which overcomes the shortcomings of insufficient power in pure hydrogen engines and the high ignition energy, slow flame propagation speed, and difficulty in ignition of pure ammonia engines. The specific technical solution is as follows.

[0007] In a first aspect, the present invention provides an ammonia-hydrogen engine based on a reforming mechanism, comprising: an engine controller, an ammonia fuel tank, a fuel pump, a multi-functional ammonia reformer, a throttle valve, a reciprocating internal combustion engine, and a controllable flow control device. The controllable flow control device includes a first valve for injecting ammonia fuel, an ammonia shut-off valve, an ammonia injection chamber, a second valve for injecting hydrogen fuel, a hydrogen shut-off valve, a hydrogen injection chamber, and a premixing chamber. The multi-functional ammonia reformer includes an electric heating device, which is equipped with a catalyst. The fuel pump, the first valve, the second valve, and the electric heating device are all electrically connected to the engine controller. The first valve and the second valve are either injection valves or high-precision proportional valves.

[0008] The throttle valve is connected to the reciprocating internal combustion engine via the intake manifold. The ammonia fuel tank is connected to the fuel pump. The fuel pump is connected to the ammonia shut-off valve and the electric heating device. The ammonia shut-off valve is connected to the first valve. The first valve is connected to the ammonia injection chamber. The electric heating device is connected to the hydrogen shut-off valve. The hydrogen shut-off valve is connected to the second valve. The second valve is connected to the hydrogen injection chamber. Both the ammonia injection chamber and the hydrogen injection chamber are connected to the premixing chamber. The premixing chamber is connected to the intake manifold.

[0009] When the engine controller detects that the ammonia-hydrogen engine is in a cold state, it controls the electric heating device to turn on, determines the engine target power of the ammonia-hydrogen engine, obtains the target throttle opening of the ammonia-hydrogen engine based on the engine target power and the preset throttle opening MAP table, obtains the target intake air volume of the ammonia-hydrogen engine based on the engine target power, the target throttle opening and the preset intake air volume MAP table, obtains the target hydrogen-ammonia fuel supply volume based on the target intake air volume, the preset air-fuel ratio, the current speed of the ammonia-hydrogen engine and the preset hydrogen-ammonia fuel supply volume MAP table, calculates the hydrogen richness ratio based on the current load of the ammonia-hydrogen engine, the preset exothermic reaction equivalence relationship between hydrogen and air, the preset exothermic reaction equivalence relationship between ammonia and air and the target hydrogen-ammonia fuel supply volume, calculates the target ammonia injection volume and the target hydrogen injection volume based on the hydrogen richness ratio and the target hydrogen-ammonia fuel supply volume, controls the injection volume of the second valve to reach the target hydrogen injection volume, and controls the injection volume of the first valve to reach the target ammonia injection volume.

[0010] Optionally, the engine controller receives the engine power requirement of the ammonia-hydrogen engine sent by the vehicle controller, calculates the accessory power based on the current load and oil temperature information of the ammonia-hydrogen engine, and calculates the engine target power based on the engine power requirement and the accessory power.

[0011] Optionally, the engine controller determines a first target combustion heat equivalent corresponding to the current load of the ammonia-hydrogen engine based on the current load of the ammonia-hydrogen engine and a preset reaction heat equivalent relationship between hydrogen and air. It also determines a second target combustion heat equivalent corresponding to the current load of the ammonia-hydrogen engine based on the same relationship. The hydrogen-rich ratio is calculated based on the first target combustion heat equivalent, the second target combustion heat equivalent, and the target hydrogen-ammonia fuel supply. The first target combustion heat equivalent is the combustion heat equivalent of hydrogen in air, and the second target combustion heat equivalent is the combustion heat equivalent of ammonia in air.

[0012] Optionally, the aforementioned ammonia-hydrogen engine also includes an exhaust temperature sensor, which is located at the turbocharger outlet of the reciprocating internal combustion engine and is signal-connected to the engine controller. The multi-functional ammonia reformer also includes an exhaust heating device, which is equipped with a catalyst.

[0013] The fuel pump is also connected to the exhaust heating device, which is connected to the hydrogen shut-off valve.

[0014] The engine controller receives the temperature signal sent by the exhaust temperature sensor. When the temperature signal reaches a preset temperature, it turns off the electric heating device or reduces the power of the electric heating device, and controls the exhaust heating device to turn on.

[0015] Optionally, the aforementioned ammonia-hydrogen engine also includes an exhaust aftertreatment device;

[0016] Both the fuel pump and the multi-functional ammonia reformer are connected to the exhaust aftertreatment device.

[0017] Optionally, the controllable flow control device further includes a temperature and pressure integrated sensor, which is disposed in the premixing chamber and is signal-connected to the engine controller;

[0018] The engine controller receives the premixing chamber pressure and temperature from the integrated temperature and pressure sensor. Based on the premixing chamber pressure, the premixing chamber temperature, and the ideal gas law, it calculates the amount of substance of the mixed gas in the premixing chamber. If the amount of substance of the mixed gas exceeds a preset target amount, it reduces the target hydrogen injection rate and the target ammonia injection rate until the amount of substance of the mixed gas equals the preset target amount. If the amount of substance of the mixed gas does not reach the preset target amount, it increases the target hydrogen injection rate and the target ammonia injection rate until the amount of substance of the mixed gas equals the preset target amount.

[0019] Optionally, the aforementioned ammonia-hydrogen engine also includes a fuel filter;

[0020] The ammonia fuel tank is connected to the fuel filter, and the fuel filter is connected to the fuel pump.

[0021] Optionally, the aforementioned ammonia-hydrogen engine further includes an air intake filter, which is disposed in the air intake manifold.

[0022] Optionally, the injection start time of the second valve is later than the injection start time of the first valve.

[0023] As described above, the ammonia-hydrogen engine based on a reforming mechanism provided in this embodiment of the invention includes an engine controller, an ammonia fuel tank, a fuel pump, a multi-functional ammonia reformer, a throttle valve, a reciprocating internal combustion engine, and a controllable flow control device. The controllable flow control device includes a first valve for injecting ammonia fuel, an ammonia shut-off valve, an ammonia injection chamber, a second valve for injecting hydrogen fuel, a hydrogen shut-off valve, a hydrogen injection chamber, and a premixing chamber. The multi-functional ammonia reformer includes an electric heating device, which is equipped with a catalyst. The fuel pump, the first valve, the second valve, and the electric heating device are all electrically connected to the engine controller. The first and second valves are either injection valves or high-precision proportional valves. The throttle valve is connected to the reciprocating internal combustion engine via the intake manifold. The ammonia fuel tank is connected to the fuel pump, which is connected to both the ammonia shut-off valve and the electric heating device. The ammonia shut-off valve is connected to the first valve, which is connected to the ammonia injection chamber. The electric heating device is connected to the hydrogen shut-off valve, which is connected to the second valve, which is connected to the hydrogen injection chamber. Both the injection chamber and the hydrogen injection chamber are connected to the premixing chamber, which is connected to the intake manifold. When the engine controller detects that the ammonia-hydrogen engine is in a cold state, it controls the electric heating device to turn on, determines the engine target power of the ammonia-hydrogen engine, obtains the target throttle opening of the ammonia-hydrogen engine based on the engine target power and the preset throttle opening MAP table, obtains the target intake air volume of the ammonia-hydrogen engine based on the engine target power, the target throttle opening, and the preset intake air volume MAP table, obtains the target hydrogen-ammonia fuel supply based on the target intake air volume, the preset air-fuel ratio, the current speed of the ammonia-hydrogen engine, and the preset hydrogen-ammonia fuel supply MAP table, calculates the hydrogen richness ratio based on the current load of the ammonia-hydrogen engine, the preset exothermic reaction equivalent relationship between hydrogen and air, the preset exothermic reaction equivalent relationship between ammonia and air, and the target hydrogen-ammonia fuel supply, calculates the target ammonia injection quantity and the target hydrogen injection quantity based on the hydrogen richness ratio and the target hydrogen-ammonia fuel supply, controls the injection quantity of the second valve to reach the target hydrogen injection quantity, and controls the injection quantity of the first valve to reach the target ammonia injection quantity. Therefore, in this embodiment of the invention, ammonia is reformed into hydrogen using a multifunctional ammonia reformer. The hydrogen then enters the premixing chamber through a second valve and mixes with the ammonia to form hydrogen-rich fuel for combustion. This overcomes the shortcomings of pure hydrogen engines (insufficient power) and pure ammonia engines (high ignition energy, slow flame propagation speed, and difficulty in ignition). Furthermore, the hydrogen enrichment ratio is calculated based on the current load of the ammonia-hydrogen engine. The target ammonia injection quantity and target hydrogen injection quantity are calculated based on the hydrogen enrichment ratio and the target hydrogen-ammonia fuel supply, thereby achieving precise control of the ammonia and hydrogen injection quantities. This makes the mixed fuel entering the reciprocating internal combustion engine easier to burn, the flame more stable, and combustion more complete. Of course, implementing any product or method of this invention does not necessarily require achieving all of the above advantages simultaneously.

[0024] The innovative aspects of this invention include:

[0025] 1. Ammonia is reformed into hydrogen through a multi-functional ammonia reformer, allowing the hydrogen to enter the premixing chamber through the second valve and mix with ammonia to form hydrogen-rich fuel for combustion. This overcomes the shortcomings of pure hydrogen engines, such as insufficient power and the high ignition energy, slow flame propagation speed, and difficulty in ignition of pure ammonia engines.

[0026] 2. The hydrogen enrichment ratio is calculated based on the current load of the ammonia-hydrogen engine. The target ammonia injection quantity and target hydrogen injection quantity are calculated based on the hydrogen enrichment ratio and the target hydrogen-ammonia fuel supply quantity, thereby achieving precise control of the ammonia injection quantity and hydrogen injection quantity, making the mixed fuel entering the reciprocating internal combustion engine easier to burn, the flame more stable, and the combustion more complete.

[0027] 3. By setting the injection start time of the second valve to be later than that of the first valve, the hydrogen-rich fuel is mixed more evenly.

[0028] 4. By installing an integrated temperature and pressure sensor in the premixing chamber and calculating the amount of mixed gas in the premixing chamber based on the premixing chamber pressure, premixing chamber temperature, and the ideal gas law, the amount of mixed gas in the premixing chamber is adjusted according to the premixing chamber pressure, premixing chamber temperature, and the ideal gas law. When the amount of mixed gas exceeds the preset target amount, the target hydrogen injection rate and target ammonia injection rate are reduced. When the amount of mixed gas does not reach the preset target amount, the target hydrogen injection rate and target ammonia injection rate are increased. This method ensures that the amount of mixed gas in the premixing chamber is equal to the preset target amount.

[0029] 5. By setting up exhaust temperature sensors and exhaust heating devices, ammonia can be reformed into hydrogen through exhaust temperature, making full use of exhaust waste heat and achieving the goal of efficient fuel utilization.

[0030] 6. By preparing urea online using ammonia, nitrogen oxides in the exhaust gas are decomposed to generate pollution-free nitrogen and water, reducing the nitrogen oxide content in the exhaust gas and achieving a clean and efficient result. This allows the ammonia-hydrogen engine to truly achieve the goal of low carbon emissions and environmental protection.

[0031] 7. By installing a fuel filter, particulate impurities, trace amounts of water, and light oil in the ammonia fuel can be removed, preventing blockages and damage caused by impurities, rust, welding slag, etc. in the pipeline. This avoids maintenance costs and production losses, and protects the normal operation of valves and other equipment. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0033] Figure 1 A schematic diagram of a reforming-based ammonia-hydrogen engine provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of a pressure closed-loop process.

[0035] Figure 1 The components include: 1. Ammonia fuel tank; 2. Fuel pump; 3. Multifunctional ammonia reformer; 4. Throttle valve; 5. Reciprocating internal combustion engine; 6. Controllable flow control device; 61. First valve; 62. Ammonia shut-off valve; 63. Ammonia injection chamber; 64. Second valve; 65. Hydrogen shut-off valve; 66. Hydrogen injection chamber; 67. Premixing chamber; 7. Intake manifold; 8. Exhaust aftertreatment device; and 9. Fuel filter. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that the terms "comprising" and "having," and any variations thereof, in the embodiments and drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0038] This invention discloses an ammonia-hydrogen engine based on a reforming mechanism, which overcomes the shortcomings of insufficient power in pure hydrogen engines and the high ignition energy, slow flame propagation speed, and difficulty in ignition of pure ammonia engines. Furthermore, it makes the mixed fuel entering the reciprocating internal combustion engine easier to burn, the flame more stable, and the combustion more complete. The embodiments of this invention are described in detail below.

[0039] Figure 1 This is a schematic diagram of an ammonia-hydrogen engine based on a reforming mechanism, provided as an embodiment of the present invention.

[0040] See Figure 1 The ammonia-hydrogen engine based on reforming mechanism provided in this embodiment of the invention includes: an engine controller, an ammonia fuel tank 1, a fuel pump 2, a multi-functional ammonia reformer 3, a throttle valve 4, a reciprocating internal combustion engine 5, and a controllable flow control device 6.

[0041] The controllable flow control device 6 includes a first valve 61 for injecting ammonia fuel, an ammonia shut-off valve 62, an ammonia injection chamber 63, a second valve 64 for injecting hydrogen fuel, a hydrogen shut-off valve 65, a hydrogen injection chamber 66, and a premixing chamber 67. The multi-functional ammonia reformer 3 includes an electric heating device, which is equipped with a catalyst. The fuel pump 2, the first valve 61, the second valve 64, and the electric heating device are all electrically connected to the engine controller. The first valve and the second valve are either injection valves or high-precision proportional valves.

[0042] For example, the catalyst in the electric heating device can be a catalyst based on ruthenium or palladium, but is not limited to this type of catalyst. There are three first valves 61 and three second valves 64. The valve data is calculated based on the flow rate and engine displacement.

[0043] See also Figure 1 Throttle valve 4 is connected to reciprocating internal combustion engine 5 via intake manifold 7. Ammonia fuel tank 1 is connected to fuel pump 2. Fuel pump 2 is connected to ammonia shut-off valve 62 and electric heating device respectively. Ammonia shut-off valve 62 is connected to first valve 61. First valve 61 is connected to ammonia injection chamber 63. Electric heating device is connected to hydrogen shut-off valve 65. Hydrogen shut-off valve 65 is connected to second valve 64. Second valve 64 is connected to hydrogen injection chamber 66. Ammonia injection chamber 63 and hydrogen injection chamber 66 are both connected to premixing chamber 67. Premixing chamber 67 is connected to intake manifold 7.

[0044] In this embodiment of the invention, ammonia is reformed into hydrogen by a multifunctional ammonia reformer 3. In order to reform ammonia into hydrogen, the ammonia needs to be heated. Therefore, when the engine controller detects that the ammonia-hydrogen engine is in a cold state, it controls the electric heating device to turn on.

[0045] Once the electric heating device is turned on, the ammonia gas can be heated to the reforming temperature by electric heating. Then, the reformed hydrogen gas is connected to the hydrogen shut-off valve 65 through a pipeline, and then injected into the hydrogen injection chamber 66 through the second valve 64, and then enters the premixing chamber 67.

[0046] Liquid ammonia in the ammonia fuel tank 1 is pumped into the ammonia shut-off valve 62 by the fuel pump 2, and then injected into the ammonia injection chamber 63 through the first valve 61 to form ammonia gas. This gas then enters the premixing chamber 67, where it mixes with hydrogen to form a hydrogen-rich fuel mixture. This mixture then mixes with fresh air passing through the throttle valve 4 in the intake manifold 7. The mixed fuel then enters the reciprocating internal combustion engine 5, and is finally ignited by the spark plug, after which it expands and performs work. The throttle valve 4 controls the air-fuel ratio of the reciprocating internal combustion engine 5.

[0047] In order to make the mixed fuel entering the reciprocating internal combustion engine 5 easier to burn, the flame more stable, and the combustion more complete, in this embodiment of the invention, not only are ammonia and hydrogen mixed, but the injection amounts of ammonia and hydrogen are also controlled.

[0048] Specifically, the engine controller determines the target engine power of the ammonia-hydrogen engine, and obtains the target throttle opening of the ammonia-hydrogen engine based on the target engine power and the preset throttle opening MAP table.

[0049] The engine controller determines the target engine power of the ammonia-hydrogen engine, which can be:

[0050] The engine controller receives the engine power demand of the ammonia-hydrogen engine from the vehicle controller, calculates the accessory power based on the current load and oil temperature information of the ammonia-hydrogen engine, and calculates the engine target power based on the engine power demand and accessory power.

[0051] The vehicle controller obtains the target power of the vehicle based on the current operating conditions of the ammonia-hydrogen engine, then calculates the engine power requirement of the ammonia-hydrogen engine through a preset vehicle model, and then sends it to the engine controller via the bus. The engine power requirement is the power generated by components other than engine accessories.

[0052] The engine controller receives the engine power demand of the ammonia-hydrogen engine from the vehicle controller. Based on the engine's current load, oil temperature, and a preset accessory power calculation method, it calculates the accessory power. Then, it calculates the engine target power based on the engine power demand and accessory power. The engine's current load and oil temperature information can be obtained through corresponding sensors.

[0053] The engine controller calculates the target engine power using the following formula:

[0054]

[0055] in, For the engine target power, To meet the engine's power requirements, For the power of the accessory.

[0056] After obtaining the engine target power, the engine controller determines the target throttle opening of the ammonia-hydrogen engine based on the engine target power and the preset throttle opening MAP table. The preset throttle opening MAP table is used to characterize the correspondence between the engine target power and the throttle opening.

[0057] Specifically, the engine controller obtains the target throttle opening of the ammonia-hydrogen engine by looking up the preset throttle opening MAP table based on the engine's target power.

[0058] Then, the engine controller obtains the target intake volume of the ammonia-hydrogen engine based on the engine target power, target throttle opening and preset intake volume MAP table, and obtains the target hydrogen-ammonia fuel supply based on the target intake volume, preset air-fuel ratio, current speed of the ammonia-hydrogen engine and preset hydrogen-ammonia fuel supply MAP table.

[0059] Specifically, the engine controller obtains the target intake volume of the ammonia-hydrogen engine by looking up the preset intake volume MAP table based on the engine target power and target throttle opening. It also obtains the target hydrogen-ammonia fuel supply by looking up the preset hydrogen-ammonia fuel supply MAP table based on the target intake volume, preset air-fuel ratio, and current engine speed.

[0060] Among them, the preset intake air volume MAP table is used to characterize the correspondence between engine target power, throttle opening and engine intake air volume, and the preset hydrogen ammonia fuel supply MAP table is used to characterize the correspondence between engine intake air volume, air-fuel ratio, engine speed and hydrogen ammonia fuel supply.

[0061] After obtaining the target hydrogen-ammonia fuel supply, that is, knowing the total amount of hydrogen and ammonia mixed fuel required, we still do not know the exact amounts of hydrogen and ammonia, that is, the injection rates of ammonia and hydrogen. In order to know the injection rates of ammonia and hydrogen, we need to determine the volume ratio of hydrogen and ammonia, that is, the hydrogen enrichment ratio.

[0062] Figure 2 For a schematic diagram of the pressure closed loop, see [link / reference]. Figure 2 To determine the hydrogen enrichment ratio, the engine controller uses the current load of the ammonia-hydrogen engine and the preset exothermic reaction equivalence between hydrogen and air (… Figure 2 (Not specified in the text) The presupposed exothermic equivalence relationship between ammonia and air (not specified in the text) Figure 2 The hydrogen enrichment ratio was calculated based on the target hydrogen-ammonia fuel supply (not specified in the text).

[0063] The engine controller calculates the hydrogen enrichment ratio based on the current load of the ammonia-hydrogen engine, the preset exothermic reaction equivalence relationship between hydrogen and air, the preset exothermic reaction equivalence relationship between ammonia and air, and the target hydrogen-ammonia fuel supply. This ratio can be:

[0064] The engine controller determines the first target combustion heat equivalent corresponding to the current load of the ammonia-hydrogen engine based on the current load of the ammonia-hydrogen engine and the preset reaction heat equivalent relationship between hydrogen and air. It also determines the second target combustion heat equivalent corresponding to the current load of the ammonia-hydrogen engine based on the same relationship. The hydrogen-rich ratio is calculated based on the first target combustion heat equivalent, the second target combustion heat equivalent, and the target hydrogen-ammonia fuel supply. The first target combustion heat equivalent is the heat equivalent of hydrogen combustion in air, and the second target combustion heat equivalent is the heat equivalent of ammonia combustion in air.

[0065] Among them, the preset reaction exothermic equivalent relationship between hydrogen and air can characterize the correspondence between the exothermic equivalent of hydrogen combustion in air and the engine load, and then the first target combustion exothermic equivalent corresponding to the current load of the ammonia-hydrogen engine can be determined.

[0066] Specifically, the heat equivalent of fuel combustion in air is obtained as follows, taking the heat equivalent of hydrogen combustion in air as an example:

[0067] Using only one fuel, such as hydrogen, the engine speed is gradually increased from idle speed until it can ignite normally; this initial speed is then used as the starting speed. The hydrogen injection quantity is then gradually increased at different speeds until combustion is just achieved, and the hydrogen injection quantity and cylinder pressure curves are recorded. By analyzing the hydrogen injection quantity, cylinder pressure curves, and engine speed, the combustion heat release rate curves for different hydrogen fuel quantities at different engine speeds can be obtained. These combustion heat release rate curves can be used to determine the equivalent heat release of hydrogen combustion in air corresponding to different engine loads. In other words, the correspondence between the equivalent heat release of hydrogen combustion in air and engine load can be established, thereby determining the first target combustion heat release equivalent corresponding to the current load of the ammonia-hydrogen engine.

[0068] The heat release equivalent of ammonia combustion in air is similar. The pre-defined reaction heat release equivalent relationship between ammonia and air can characterize the correspondence between the heat release equivalent of ammonia combustion in air and the engine load, thereby determining the second target combustion heat release equivalent corresponding to the current load of the ammonia-hydrogen engine.

[0069] After obtaining the first target combustion heat release equivalent and the second target combustion heat release equivalent, the engine controller calculates the hydrogen richness ratio based on the first target combustion heat release equivalent, the second target combustion heat release equivalent, the target hydrogen-ammonia fuel supply, and the preset hydrogen richness ratio calculation formula.

[0070] Once the hydrogen enrichment ratio is obtained, the engine controller can calculate the target ammonia injection rate and the target hydrogen injection rate based on the hydrogen enrichment ratio and the target hydrogen ammonia fuel supply.

[0071] The target ammonia injection rate and target hydrogen injection rate, calculated based on the hydrogen richness ratio and the target hydrogen-ammonia fuel supply, can be:

[0072] The target hydrogen injection rate is calculated by multiplying the hydrogen enrichment ratio and the target hydrogen-ammonia fuel supply. The target ammonia injection rate is calculated by the difference between the target hydrogen-ammonia fuel supply and the target hydrogen injection rate.

[0073] See also Figure 2 After obtaining the target ammonia injection quantity and the target hydrogen injection quantity, the engine controller can use an algorithm to change the hydrogen injection duty cycle to make the injection quantity of the second valve reach the target hydrogen injection quantity, and use an algorithm to change the ammonia injection duty cycle to make the injection quantity of the first valve reach the target ammonia injection quantity. Then, the mixed gas filling the premixing chamber 67 generates pressure, namely the target fuel supply pressure, which further causes the target fuel to enter the reciprocating internal combustion engine 5. The target fuel is the mixed fuel mentioned above.

[0074] Specifically, the engine controller determines the ammonia injection duty cycle corresponding to the target ammonia injection quantity and the hydrogen injection duty cycle corresponding to the target hydrogen injection quantity according to the preset PEAK-HOLD algorithm, controls the second valve to inject at the hydrogen injection duty cycle, and controls the first valve to inject at the ammonia injection duty cycle.

[0075] In summary, the ammonia-hydrogen engine in this embodiment of the invention includes an engine controller, an ammonia fuel tank 1, a fuel pump 2, a multi-functional ammonia reformer 3, a throttle valve 4, a reciprocating internal combustion engine 5, and a controllable flow control device 6. The controllable flow control device 6 includes a first valve 61 for injecting ammonia fuel, an ammonia shut-off valve 62, an ammonia injection chamber 63, a second valve 64 for injecting hydrogen fuel, a hydrogen shut-off valve 65, a hydrogen injection chamber 66, and a premixing chamber 67. The multi-functional ammonia reformer 3 includes an electric heating device, which is equipped with a catalyst. The fuel pump 2, the first valve 61, the second valve 64, and the electric heating device are all electrically connected to the engine controller. The first valve and the second valve are injection valves or high-precision proportional valves. Throttle valve 4 is connected to reciprocating internal combustion engine 5 via intake manifold 7. Ammonia fuel tank 1 is connected to fuel pump 2. Fuel pump 2 is connected to ammonia shut-off valve 62 and electric heating device respectively. Ammonia shut-off valve 62 is connected to first valve 61. First valve 61 is connected to ammonia injection chamber 63. Electric heating device is connected to hydrogen shut-off valve 65. Hydrogen shut-off valve 65 is connected to second valve 64. Second valve 64 is connected to hydrogen injection chamber 66. Ammonia injection chamber 63 and hydrogen injection chamber 66 are both connected to premixing chamber 67. Premixing chamber 67 is connected to intake manifold 7. When the engine controller detects that the ammonia-hydrogen engine is in a cold state, it controls the electric heating device to turn on, determines the engine target power of the ammonia-hydrogen engine, obtains the target throttle opening of the ammonia-hydrogen engine based on the engine target power and the preset throttle opening MAP table, obtains the target intake air volume of the ammonia-hydrogen engine based on the engine target power, target throttle opening and the preset intake air volume MAP table, obtains the target hydrogen-ammonia fuel supply based on the target intake air volume, preset air-fuel ratio, current speed of the ammonia-hydrogen engine and preset hydrogen-ammonia fuel supply MAP table, calculates the hydrogen richness ratio based on the current load of the ammonia-hydrogen engine, the preset exothermic reaction equivalent relationship between hydrogen and air, the preset exothermic reaction equivalent relationship between ammonia and air, and the target hydrogen-ammonia fuel supply, calculates the target ammonia injection quantity and target hydrogen injection quantity based on the hydrogen richness ratio and the target hydrogen-ammonia fuel supply, controls the injection quantity of the second valve to reach the target hydrogen injection quantity, and controls the injection quantity of the first valve to reach the target ammonia injection quantity. Therefore, in this embodiment of the invention, ammonia is reformed into hydrogen by a multifunctional ammonia reformer 3, allowing the hydrogen to enter the premixing chamber 67 through the second valve 64 and mix with ammonia to form hydrogen-rich fuel for combustion. This overcomes the shortcomings of insufficient power in a pure hydrogen engine and the high ignition energy, slow flame propagation speed, and difficulty in ignition of a pure ammonia engine. Furthermore, the hydrogen enrichment ratio is calculated based on the current load of the ammonia-hydrogen engine, and the target ammonia injection quantity and target hydrogen injection quantity are calculated based on the hydrogen enrichment ratio and the target hydrogen-ammonia fuel supply quantity. This achieves precise control of the ammonia injection quantity and hydrogen injection quantity, making the mixed fuel entering the reciprocating internal combustion engine 5 easier to burn, the flame more stable, and the combustion more complete.

[0076] Because hydrogen diffuses quickly, in order to make the hydrogen-rich fuel mix more evenly, the injection start time of the second valve is set later than that of the first valve. The specific time by which the injection start time of the second valve is later than that of the first valve is calculated based on the current load of the ammonia-hydrogen engine and the hydrogen enrichment ratio.

[0077] Therefore, by setting the injection start time of the second valve to be later than that of the first valve, the hydrogen-rich fuel is mixed more evenly.

[0078] To ensure combustion stability and power output stability, the gas entering the premixing chamber 67 needs to be pressure closed-loop. Therefore, the controllable flow control device 6 also includes a temperature and pressure integrated sensor, which is located in the premixing chamber 67 and is connected to the engine controller signal.

[0079] See also Figure 2 The engine controller receives the premixing chamber pressure (target fuel supply pressure) from the integrated temperature and pressure sensor. It checks if the premixing chamber pressure equals the preset target pressure. If not, it needs to recalculate the target hydrogen-ammonia fuel supply. Specifically, it obtains the new engine power demand, updates the engine power demand value accordingly, and returns to execute the calculation of the engine target power based on the engine power demand and accessory power. Then, it performs subsequent steps to recalculate the target hydrogen-ammonia fuel supply until the premixing chamber pressure equals the preset target pressure. The target fuel then enters the reciprocating internal combustion engine 5. Therefore, when the premixing chamber pressure is not equal to the preset target pressure, the target hydrogen-ammonia fuel supply is recalculated until the premixing chamber pressure equals the preset target pressure by obtaining the new engine power demand value and updating it accordingly. This achieves pressure closed-loop control of the gas entering the premixing chamber 67, ensuring combustion stability and power output stability.

[0080] Furthermore, the obtained target hydrogen injection rate and target ammonia injection rate are used to ensure that the volume of the mixed gas in the premixing chamber reaches the preset target volume. If the target volume is not reached, the target hydrogen injection rate and target ammonia injection rate need to be changed.

[0081] Specifically, the engine controller receives the premixing chamber pressure and temperature from the integrated temperature and pressure sensor. Based on the premixing chamber pressure, premixing chamber temperature, and the ideal gas law, it calculates the amount of gas mixture in the premixing chamber. If the amount of gas mixture exceeds the preset target amount, it reduces the target hydrogen injection rate and the target ammonia injection rate until the amount of gas mixture equals the preset target amount. If the amount of gas mixture does not reach the preset target amount, it increases the target hydrogen injection rate and the target ammonia injection rate until the amount of gas mixture equals the preset target amount.

[0082] Therefore, by installing an integrated temperature and pressure sensor in the premixing chamber and calculating the amount of mixed gas in the premixing chamber based on the premixing chamber pressure, premixing chamber temperature, and the ideal gas law, the amount of mixed gas in the premixing chamber can be equal to the amount of the preset target amount when the amount of mixed gas exceeds the preset target amount, and the target hydrogen injection rate and target ammonia injection rate can be reduced when the amount of mixed gas does not reach the preset target amount.

[0083] Since the reciprocating internal combustion engine 5 is in a hot state after starting, the exhaust gas also has a temperature, usually between 500℃ and 700℃. The temperature required for ammonia reforming is within this range. Therefore, the exhaust gas temperature can meet the requirements of ammonia reforming. In order not to waste exhaust heat, the exhaust gas temperature is also used as the temperature for hydrogen production by ammonia reforming in this embodiment of the invention.

[0084] See also Figure 1 The ammonia-hydrogen engine also includes an exhaust temperature sensor, which is located at the turbocharger outlet of the reciprocating internal combustion engine 5. The exhaust temperature sensor is connected to the engine controller signal. The multi-functional ammonia reformer 3 also includes an exhaust heating device, which is equipped with a catalyst. For example, the catalyst in the exhaust heating device can be a catalyst based on ruthenium or palladium, but is not limited to this type of catalyst.

[0085] Fuel pump 2 is also connected to exhaust heating device, which is connected to hydrogen shut-off valve 65. Engine controller receives temperature signal sent by exhaust temperature sensor. When the temperature signal reaches the preset temperature, it means that the exhaust temperature can meet the requirements of ammonia reforming. The controller then turns off the electric heating device or reduces the power of the electric heating device and controls the exhaust heating device to turn on.

[0086] After the exhaust heating device is turned on, the ammonia can be heated to the reforming temperature by exhaust heating. Then, the reformed hydrogen is connected to the hydrogen shut-off valve 65 through a pipeline, and then injected into the hydrogen injection chamber 66 through the second valve 64. It then enters the premixing chamber 67 to mix with the ammonia to form hydrogen-rich fuel.

[0087] Therefore, by setting up exhaust temperature sensors and exhaust heating devices, ammonia can be reformed into hydrogen through exhaust temperature, making full use of exhaust waste heat and achieving the goal of efficient fuel utilization.

[0088] As the load on the ammonia-hydrogen engine increases, the cylinder temperature and pressure will rise. When the temperature reaches or exceeds the nitrogen oxide synthesis temperature, a certain amount of nitrogen oxides will be synthesized. At this time, the concentration of nitrogen oxides in the exhaust gas will increase accordingly, and nitrogen oxides will cause air pollution.

[0089] Therefore, in order to reduce pollution, please continue to see Figure 1 The ammonia-hydrogen engine also includes an exhaust aftertreatment device 8, a fuel pump 2, and a multi-functional ammonia reformer 3, all of which are connected to the exhaust aftertreatment device 8.

[0090] Ammonia in fuel pump 2 reacts with exhaust gas to generate urea, which is then injected into exhaust aftertreatment device 8 via urea pump. Urea then reacts with nitrogen oxides in the exhaust gas to generate nitrogen and water.

[0091] Therefore, by using ammonia to produce urea online to decompose nitrogen oxides in the exhaust gas, pollution-free nitrogen and water are generated, reducing the nitrogen oxide content in the exhaust gas and achieving the goal of cleanliness and efficiency, making the ammonia-hydrogen engine truly achieve the goal of low carbon and environmental protection.

[0092] To remove impurities from ammonia fuel, see [link to relevant documentation]. Figure 1 The ammonia-hydrogen engine also includes a fuel filter 9, which is connected to the ammonia fuel tank 1 and the fuel filter 9, which is connected to the fuel pump 2. This ensures that the ammonia gas entering the subsequent ammonia shut-off valve 62 and the multi-functional ammonia reformer 3 contains fewer impurities.

[0093] Therefore, by installing a fuel filter 9, particulate impurities, trace amounts of water, and light oil in the ammonia fuel are removed, preventing blockage and damage caused by impurities, rust, welding shavings, etc. in the pipeline, thus avoiding maintenance costs and production losses, and protecting the normal use of valves and other equipment.

[0094] In addition, to remove impurities from the air, the ammonia-hydrogen engine also includes an air intake filter, which is located in the air intake manifold 7.

[0095] Therefore, by installing an intake filter, impurities in the air entering the reciprocating internal combustion engine 5 are reduced.

[0096] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0097] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ammonia-hydrogen engine based on a reforming mechanism, characterized in that, include: The engine controller, ammonia fuel tank, fuel pump, multi-functional ammonia reformer, throttle valve, reciprocating internal combustion engine, and controllable flow control device are included. The controllable flow control device comprises a first valve for injecting ammonia fuel, an ammonia shut-off valve, an ammonia injection chamber, a second valve for injecting hydrogen fuel, a hydrogen shut-off valve, a hydrogen injection chamber, and a premixing chamber. The multi-functional ammonia reformer includes an electric heating device with a catalyst. The fuel pump, the first valve, the second valve, and the electric heating device are all electrically connected to the engine controller. The first valve and the second valve are either injection valves or high-precision proportional valves. The throttle valve is connected to the reciprocating internal combustion engine via the intake manifold. The ammonia fuel tank is connected to the fuel pump. The fuel pump is connected to the ammonia shut-off valve and the electric heating device. The ammonia shut-off valve is connected to the first valve. The first valve is connected to the ammonia injection chamber. The electric heating device is connected to the hydrogen shut-off valve. The hydrogen shut-off valve is connected to the second valve. The second valve is connected to the hydrogen injection chamber. Both the ammonia injection chamber and the hydrogen injection chamber are connected to the premixing chamber. The premixing chamber is connected to the intake manifold. When the engine controller detects that the ammonia-hydrogen engine is in a cold state, it controls the electric heating device to turn on, determines the engine target power of the ammonia-hydrogen engine, obtains the target throttle opening of the ammonia-hydrogen engine based on the engine target power and the preset throttle opening MAP table, obtains the target intake volume of the ammonia-hydrogen engine based on the engine target power, the target throttle opening and the preset intake volume MAP table, obtains the target hydrogen-ammonia fuel supply volume based on the target intake volume, the preset air-fuel ratio, the current speed of the ammonia-hydrogen engine and the preset hydrogen-ammonia fuel supply volume MAP table, calculates the hydrogen richness ratio based on the current load of the ammonia-hydrogen engine, the preset exothermic reaction equivalence relationship between hydrogen and air, the preset exothermic reaction equivalence relationship between ammonia and air and the target hydrogen-ammonia fuel supply volume, calculates the target ammonia injection volume and the target hydrogen injection volume based on the hydrogen richness ratio and the target hydrogen-ammonia fuel supply volume, controls the injection volume of the second valve to reach the target hydrogen injection volume, and controls the injection volume of the first valve to reach the target ammonia injection volume; The engine controller determines a first target combustion heat equivalent corresponding to the current load of the ammonia-hydrogen engine based on the current load of the ammonia-hydrogen engine and a preset reaction heat equivalent relationship between hydrogen and air. It also determines a second target combustion heat equivalent corresponding to the current load of the ammonia-hydrogen engine based on the same relationship. The hydrogen-rich ratio is calculated based on the first target combustion heat equivalent, the second target combustion heat equivalent, and the target hydrogen-ammonia fuel supply. The first target combustion heat equivalent is the combustion heat equivalent of hydrogen in air, and the second target combustion heat equivalent is the combustion heat equivalent of ammonia in air.

2. The ammonia-hydrogen engine as described in claim 1, characterized in that, The engine controller receives the engine power requirement of the ammonia-hydrogen engine from the vehicle controller, calculates the accessory power based on the current load and oil temperature information of the ammonia-hydrogen engine, and calculates the engine target power based on the engine power requirement and the accessory power.

3. The ammonia-hydrogen engine as described in claim 1, characterized in that, The ammonia-hydrogen engine also includes an exhaust temperature sensor, which is located at the turbocharger outlet of the reciprocating internal combustion engine. The exhaust temperature sensor is connected to the engine controller. The multi-functional ammonia reformer also includes an exhaust heating device, which is equipped with a catalyst. The fuel pump is also connected to the exhaust heating device, which is connected to the hydrogen shut-off valve. The engine controller receives the temperature signal sent by the exhaust temperature sensor. When the temperature signal reaches a preset temperature, it turns off the electric heating device or reduces the power of the electric heating device, and controls the exhaust heating device to turn on.

4. The ammonia-hydrogen engine as described in any one of claims 1-3, characterized in that, The ammonia-hydrogen engine also includes an exhaust aftertreatment device; Both the fuel pump and the multi-functional ammonia reformer are connected to the exhaust aftertreatment device.

5. The ammonia-hydrogen engine as described in claim 1, characterized in that, The controllable flow control device also includes a temperature and pressure integrated sensor, which is disposed in the premixing chamber and is signal-connected to the engine controller; The engine controller receives the premixing chamber pressure and temperature from the integrated temperature and pressure sensor. Based on the premixing chamber pressure, the premixing chamber temperature, and the ideal gas law, it calculates the amount of substance of the mixed gas in the premixing chamber. If the amount of substance of the mixed gas exceeds a preset target amount, it reduces the target hydrogen injection rate and the target ammonia injection rate until the amount of substance of the mixed gas equals the preset target amount. If the amount of substance of the mixed gas does not reach the preset target amount, it increases the target hydrogen injection rate and the target ammonia injection rate until the amount of substance of the mixed gas equals the preset target amount.

6. The ammonia-hydrogen engine as described in any one of claims 1-3, characterized in that, The ammonia-hydrogen engine also includes a fuel filter; The ammonia fuel tank is connected to the fuel filter, and the fuel filter is connected to the fuel pump.

7. The ammonia-hydrogen engine as described in any one of claims 1-3, characterized in that, The ammonia-hydrogen engine also includes an air intake filter, which is disposed in the air intake manifold.

8. The ammonia-hydrogen engine as described in any one of claims 1-3, characterized in that, The injection start time of the second valve is later than the injection start time of the first valve.

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