Urea-assisted hydrogen internal combustion engine and hydrogen internal combustion engine control method

Abstract

The invention provides a urea-assisted hydrogen internal combustion engine and a hydrogen internal combustion engine control method, and relates to the technical field of hydrogen internal combustion engines. The urea-assisted hydrogen internal combustion engine comprises an internal combustion engine body, a knock sensor and a urea injection system, hydrogen serves as fuel of the internal combustion engine body, the internal combustion engine body is provided with an air inlet channel, an air inlet valve and an air cylinder, the air inlet channel communicates with the air cylinder through an air inlet, and the air inlet valve is movably installed at the air inlet to open and close the air inlet. The knock sensor is installed on the internal combustion engine body and used for detecting whether abnormal combustion occurs in the air cylinder or not. The urea injection system is provided with a first urea nozzle installed at the position of the air inlet channel, the urea injection system is electrically connected with the knock sensor, the first urea nozzle is used for injecting a urea solution to the air inlet channel after the knock sensor detects that abnormal combustion occurs in the air cylinder, and the urea solution and hydrogen are mixed and combusted in the air cylinder, so that the combustion efficiency of the air cylinder is improved. Therefore, abnormal combustion conditions such as knocking and preignition are inhibited.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen internal combustion engines, and in particular to a urea-assisted hydrogen internal combustion engine and a hydrogen internal combustion engine control method. Background Art

[0003] Due to the low density of hydrogen and the difficulty of compression ignition, hydrogen internal combustion engines generally use spark plug ignition and lean combustion. Therefore, it is necessary to accurately control the intake volume and hydrogen injection volume to ensure the formation of an effective mixture in the cylinder. For intake port injection hydrogen internal combustion engines, the hydrogen injection pressure is generally controlled at 0.3-3MPa, and since hydrogen can be premixed with air in the intake duct before entering the cylinder, it can ensure the efficient combustion of hydrogen and reduce combustion byproducts. At the same time, the air duct layout of such systems is simple and the modification cost is low. However, the power density of intake port injection hydrogen internal combustion engines is low, and there is a risk of backfire, which is prone to pre-ignition. For direct injection hydrogen internal combustion engines, the hydrogen injection pressure is generally controlled at 1.5-30MPa. Since the fuel does not pass through the intake duct, the risk of backfire and pre-ignition is reduced, and a higher power density can be achieved, but direct injection hydrogen internal combustion engines usually have higher NOx emissions. In general, hydrogen internal combustion engines still have occasional cylinder detonation and pre-ignition, which is one of the bottlenecks for hydrogen internal combustion engines to improve power density. Summary of the invention

[0004] The purpose of the present invention is to provide a urea-assisted hydrogen internal combustion engine, which can improve the problem of abnormal combustion such as knock and pre-ignition in the prior art hydrogen internal combustion engine.

[0005] Another object of the present invention is to provide a hydrogen internal combustion engine control method, which can improve the problem of abnormal combustion such as knock and pre-ignition in the hydrogen internal combustion engine in the prior art.

[0006] The embodiments of the present invention can be implemented in the following ways:

[0007] A urea-assisted hydrogen internal combustion engine, the urea-assisted hydrogen internal combustion engine comprising an internal combustion engine body, the internal combustion engine body using hydrogen as fuel; the internal combustion engine body having an intake passage, an intake valve and a cylinder, the intake passage being connected to the cylinder through an intake port, the intake valve being movably mounted at the intake port to open and close the intake port; the urea-assisted hydrogen internal combustion engine further comprising:

[0008] a knock sensor, the knock sensor being mounted on the internal combustion engine body and being used to detect whether abnormal combustion occurs in the cylinder; and

[0009] A urea injection system, wherein the urea injection system has a first urea nozzle, and the first urea nozzle is installed at the intake duct; the urea injection system is electrically connected to the knock sensor, and the first urea nozzle is used to inject urea solution into the intake duct after the knock sensor detects abnormal combustion in the cylinder.

[0010] Optionally, the urea-assisted hydrogen internal combustion engine further comprises a temperature regulating structure, and the temperature regulating structure is used to maintain the temperature of the urea solution at the first urea nozzle within a preset range.

[0011] Optionally, the temperature regulating structure includes a liquid storage tank and a temperature regulating pipe, both ends of the temperature regulating pipe are connected to the liquid storage tank, and the temperature regulating pipe is connected to the first urea nozzle so that the temperature of the urea solution at the first urea nozzle is maintained within the preset range through heat exchange between the liquid in the temperature regulating pipe and the first urea nozzle.

[0012] Optionally, the urea solution sprayed from the first urea nozzle is a urea aqueous solution with a concentration of 40% to 60%, and the preset range is 28°C to 50°C.

[0013] Optionally, the urea nozzle sprays toward the back side of the intake valve.

[0014] Optionally, a distance between the first urea nozzle and the air inlet is L, 50 mm ≤ L ≤ 100 mm.

[0015] Optionally, the urea injection system further includes a second urea nozzle, and the internal combustion engine body further includes a post-treatment system, and the second urea nozzle is used to inject urea solution into the post-treatment system.

[0016] Optionally, the internal combustion engine body further comprises a hydrogen fuel supply system, the hydrogen fuel supply system comprises a hydrogen fuel nozzle; the hydrogen fuel nozzle is installed in the intake passage to inject hydrogen fuel into the intake passage; or,

[0017] The hydrogen fuel nozzle is installed at the cylinder to inject the hydrogen fuel into the cylinder.

[0018] A hydrogen internal combustion engine control method is used to control the above-mentioned urea-assisted hydrogen internal combustion engine; the hydrogen internal combustion engine control method comprises:

[0019] Obtain abnormal combustion signals;

[0020] During the intake valve opening phase of the next working cycle after the abnormal combustion signal is acquired, the first urea nozzle is controlled to spray urea solution into the intake passage.

[0021] Optionally, during the intake valve opening phase, the first urea nozzle performs a single or double injection into the intake passage.

[0022] The beneficial effects of the urea-assisted hydrogen internal combustion engine and the hydrogen internal combustion engine control method provided by the embodiments of the present invention include:

[0023] An embodiment of the present invention provides a urea-assisted hydrogen internal combustion engine, which includes an internal combustion engine body, a knock sensor, and a urea injection system. The internal combustion engine body uses hydrogen as fuel, and the internal combustion engine body has an intake duct, an intake valve, and a cylinder. The intake duct is connected to the cylinder through an intake port, and the intake valve is movably installed at the intake port to open and close the intake port. The knock sensor is installed on the internal combustion engine body, and the knock sensor is used to detect whether abnormal combustion occurs in the cylinder. The urea injection system has a first urea nozzle, which is installed at the intake duct, and the urea injection system is electrically connected to the knock sensor. The first urea nozzle is used to inject urea solution into the intake duct after the knock sensor detects abnormal combustion in the cylinder, and the urea solution and hydrogen are mixed and burned in the cylinder, thereby suppressing the occurrence of abnormal combustion such as knock and pre-ignition.

[0024] An embodiment of the present invention also provides a hydrogen internal combustion engine control method, which is used to control the above-mentioned urea-assisted hydrogen internal combustion engine, by controlling the first urea nozzle to inject urea solution during the intake valve opening stage of the next working cycle when the knock sensor detects abnormal combustion, so that the urea solution is mixed with hydrogen in the cylinder to combust, thereby suppressing the occurrence of abnormal combustion conditions such as knock and pre-ignition. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0026] Figure 1 A partial structural schematic diagram of a urea-assisted hydrogen internal combustion engine provided according to one aspect of the present invention is shown;

[0027] Figure 2 A partial structural schematic diagram of a urea-assisted hydrogen internal combustion engine provided according to another aspect of the present invention is shown;

[0028] Figure 3 A step diagram of a hydrogen internal combustion engine control method provided according to one aspect of the present invention is shown.

[0029] Reference numerals:

[0030] 10-urea-assisted hydrogen internal combustion engine; 100-internal combustion engine body; 111-engine body; 112-cylinder; 113-cylinder head; 114-intake duct; 115-intake valve; 116-intake port; 117-exhaust duct; 120-hydrogen fuel supply system; 121-hydrogen fuel nozzle; 122-hydrogen fuel storage tank; 130-after-treatment system; 211-knock sensor; 212-signal processor; 300-urea injection system; 311-first urea nozzle; 312-urea solution storage tank; 313-second urea nozzle; 400-temperature regulation structure; 411-liquid storage tank; 412-temperature regulation pipe. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0032] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", "vertical" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] At the same time, it should be noted that the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0034] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, an integral connection, or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or the internal communication of two components, etc. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Figure 1 This is a partial structural diagram of the urea-assisted hydrogen internal combustion engine 10 provided in this embodiment. Figure 1The present embodiment provides a urea-assisted hydrogen internal combustion engine 10, which includes an internal combustion engine body 100. The internal combustion engine body 100 uses hydrogen as fuel, and the internal combustion engine body 100 has an intake duct 114, an intake valve 115, and a cylinder 112. The intake duct 114 is connected to the cylinder 112 through an intake port 116, and the intake valve 115 is movably installed at the intake port 116 to open and close the intake port 116. Specifically, the internal combustion engine body 100 can adopt the main body of a conventional hydrogen internal combustion engine, which includes a body 111 and a cylinder head 113. The cylinder 112 is located in the body 111, and the cylinder head 113 is fixedly installed above the body 111. The cylinder head 113 is provided with an intake duct 114, and an opening at one end of the intake duct 114 is connected to the cylinder 112, so that the opening at this end of the intake duct 114 is the intake port 116. The intake valve 115 is movably disposed on the cylinder head 113 and can be raised and lowered relative to the intake port 116 to open and close the intake port 116. When the intake port 116 is opened, the airflow in the intake passage 114 can enter the cylinder 112 through the intake port 116 for fuel combustion.

[0036] Since the internal combustion engine body 100 uses hydrogen as fuel, accordingly, it also has a hydrogen fuel supply system 120, and the hydrogen fuel supply system 120 includes a hydrogen fuel nozzle 121, and hydrogen fuel is injected through the hydrogen fuel nozzle 121. Figure 1 As shown, the hydrogen fuel nozzle 121 is installed in the intake duct 114, so the hydrogen internal combustion engine is an injection type internal combustion engine using the intake duct 114. It can be understood that in some other embodiments, the position of the hydrogen fuel nozzle 121 can also be set according to needs. As an example, Figure 2 A partial structural diagram of another urea-assisted hydrogen internal combustion engine 10 provided in this embodiment is shown. Figure 2 As shown, in this urea-assisted hydrogen internal combustion engine 10, a hydrogen fuel nozzle 121 is installed at the cylinder 112, and hydrogen fuel can be directly injected into the cylinder 112. In other words, the hydrogen internal combustion engine can also be set to a direct-injection type.

[0037] Specifically, the hydrogen combustion supply system further includes a hydrogen fuel storage tank 122 , which is connected to the hydrogen fuel nozzle 121 to provide hydrogen fuel to the hydrogen fuel nozzle 121 .

[0038] The urea-assisted hydrogen internal combustion engine 10 further includes a knock sensor 211 and a urea injection system 300. The knock sensor 211 is mounted on the internal combustion engine body 100, and the knock sensor 211 is used to detect whether abnormal combustion occurs in the cylinder 112. Specifically, the knock sensor 211 is mounted on the cylinder head 113, and the knock sensor 211 is used to detect the combustion condition in the cylinder 112. Optionally, the knock sensor 211 can adopt a patch structure.

[0039] The urea injection system 300 is electrically connected to the knock sensor 211, and the urea injection system 300 has a first urea nozzle 311, which is installed at the intake passage 114. After the knock sensor 211 detects abnormal combustion in the cylinder 112, the urea solution is injected into the intake passage 114. Optionally, the urea-assisted hydrogen internal combustion engine 10 further has a signal processor 212, and the first urea nozzle 311 and the knock sensor 211 are both electrically connected to the signal processor 212. The knock sensor 211 transmits the detected abnormal combustion signal to the signal processor 212. After the signal processor 212 obtains the signal, it sends a control signal to the first urea nozzle 311, thereby controlling the first urea nozzle 311 to inject urea solution during the opening stage of the intake valve 115 of the next working cycle. It can be understood that in some other embodiments, the urea injection system 300 can also be configured as a structure with a built-in control structure such as a controller or a signal processor, and the knock sensor 211 is used to transmit signals with the built-in control structure in the urea injection system 300, and the control structure sends a control signal to the first urea nozzle 311.

[0040] The first urea nozzle 311 sprays urea solution into the intake passage 114 during the opening phase of the intake valve 115. The urea enters the cylinder 112 along with the airflow in the intake passage 114. The urea solution and hydrogen are mixed and burned in the cylinder 112, thereby suppressing the occurrence of abnormal combustion conditions such as knock and pre-ignition. Specifically, after the urea solution enters the cylinder 112, the temperature in the cylinder 112 gradually increases, and the urea is thermally decomposed to generate ammonia. The chemical reaction equation is as follows:

[0041] CO(NH2)2+H2O=CO2+2NH3

[0042] The generated ammonia and the injected hydrogen are mixed and burned in the cylinder 112, and the main products are water (H2O) and nitrogen (N2) and a small amount of nitrogen oxides (NOx). At the same time, a small amount of ammonia will also burn to generate water (H2O) and nitrogen (N2) and a small amount of nitrogen oxides (NOx) after reaching the auto-ignition point of 651.1°C. In addition, the generated water will reduce the temperature in the cylinder. Under the same temperature conditions, the increase of nitrogen and ammonia will increase the combustion inertia, and suppress the occurrence of knocking and pre-ignition to a certain extent.

[0043] Further, the urea injection system 300 further includes a urea solution storage tank 312, in which urea solution is stored, and the first urea nozzle 311 is in communication with the urea solution storage tank 312, and the urea solution is supplied to the first urea nozzle 311 through the urea solution storage tank 312. In this embodiment, the urea solution injected into the intake passage 114 by the first urea nozzle 311 is a urea aqueous solution. Optionally, in this embodiment, the concentration of the urea aqueous solution is 40% to 60%.

[0044] Furthermore, the first urea nozzle 311 is installed at a position of the intake passage 114 close to the intake valve 115, and directly sprays the urea solution to the back of the intake valve 115. It should be noted that, in this embodiment, the injection time of the first urea nozzle 311 is the stage when the intake valve 115 is in the starting state, so the injection direction of the first urea nozzle 311 can be regarded as facing the back of the intake valve 115 when the intake valve 115 is opened, or when the up and down movement of the intake valve 115 is small, the injection direction of the first urea nozzle 311 can be regarded as always facing the back of the intake valve 115.

[0045] Optionally, the distance between the first urea nozzle 311 and the intake valve 115 is L, 50mm≤L≤100mm. Specifically, the distance L between the first urea nozzle 311 and the intake valve 115 can be set to 50mm, 80mm or 100mm. It is understandable that in some other embodiments, it can also be set to other values ​​within the range of 50mm to 100mm. Further, the urea solution injection pressure is 3bar to 10bar, and the atomization particle size target is 50μm to 150μm. Too coarse will lead to incomplete evaporation, and too fine may be directly carried away by the airflow. At the same time, the first urea nozzle 311 needs to ensure that the urea solution is evenly atomized, otherwise it will lead to insufficient decomposition and reduce the urea conversion efficiency.

[0046] The spray installation angle of the first urea nozzle 311 can be set according to the shape of the intake duct 114 to prevent the urea solution from being directly sprayed onto the wall of the intake duct 114 and causing crystal accumulation. Further, the spray cone angle of the first urea nozzle 311 can generally be set to 15° to 30°.

[0047] Optionally, in order to prevent the first urea nozzle 311 from leaking or being damaged due to corrosion by the urea solution, the first urea nozzle 311 needs to be made of corrosion-resistant materials, such as stainless steel, special materials, etc. At the same time, the pipe sealing ring at the connection may be regularly checked for aging and leakage.

[0048] In this embodiment, the urea-assisted hydrogen internal combustion engine 10 further includes a temperature regulating structure 400, which is used to maintain the temperature of the urea solution at the first urea nozzle 311 within a preset range. Specifically, when the ambient temperature is lower than the low temperature limit or higher than the high temperature limit, the urea solution will crystallize. For example, a 32.5% urea solution will crystallize at a temperature lower than -11°C, which affects the urea decomposition efficiency. The temperature regulating structure 400 can be used to maintain the temperature of the urea solution within a preset range to ensure that the urea solution sprayed from the first urea nozzle 311 does not have the problem of crystallization.

[0049] Optionally, in this embodiment, the concentration of the urea solution is 40% to 60%, and the preset range is set to be within the range of 28° C. to 50° C. When the temperature of the urea solution is lower than the preset range, the temperature regulating structure 400 is used to heat the urea solution at the first urea nozzle 311; when the temperature of the urea solution is higher than the preset range, the temperature regulating structure 400 is used to cool the urea solution at the first urea nozzle 311.

[0050] Optionally, the temperature regulating structure 400 includes a liquid storage tank 411 and a temperature regulating pipe 412, both ends of the temperature regulating pipe 412 are connected to the liquid storage tank 411, and the temperature regulating pipe 412 is connected to the first urea nozzle 311, so that heat exchange is performed between the liquid in the temperature regulating pipe 412 and the first urea nozzle 311, so that the temperature of the urea solution at the first urea nozzle 311 is maintained within a preset range.

[0051] Specifically, both ends of the temperature regulating tube 412 are respectively connected to the liquid storage tank 411. The middle part of the temperature regulating tube 412 can be arranged around the outside of the first urea nozzle 311, so that the heat exchange liquid enters the temperature regulating tube 412 from the liquid storage tank 411, exchanges heat with the first urea nozzle 311 while flowing along the temperature regulating tube 412, and the heat exchange liquid after the heat exchange continues to flow back to the liquid storage tank 411 along the temperature regulating tube 412.

[0052] It is understandable that in some other embodiments, other methods may be used to connect the temperature regulating tube 412, so as to adjust the urea temperature in the first urea nozzle 311. For example, a heat exchange channel may be provided inside the first urea nozzle 311, and the temperature regulating tube 412 may be provided as two independent pipes, wherein the two ends of one pipe are respectively connected to the heat exchange channel and the liquid storage tank 411, so as to guide the heat exchange liquid in the liquid storage tank 411 to flow into the heat exchange channel, and the two ends of the other pipe are also respectively connected to the heat exchange channel and the liquid storage tank 411, so as to make the heat exchange liquid in the heat exchange channel flow back to the liquid storage tank 411.

[0053] In this embodiment, the internal combustion engine body 100 further includes a post-treatment system 130, which is a system for performing exhaust gas treatment and is connected to the exhaust passage 117. The urea injection system 300 further includes a second urea nozzle 313, which is used to inject urea into the post-treatment system 130. Specifically, the second urea nozzle 313 is connected to the urea solution storage tank 312, and the second urea nozzle 313 is installed at the post-treatment system 130, and the exhaust gas is treated by injecting urea solution into the post-treatment system 130. The post-treatment system 130 is a urea thermal decomposition SCR denitration system.

[0054] SCR denitrification technology is a technology that reduces nitrogen oxide (NOx) emissions through catalytic reduction reactions. Its basic principle is to use a selective catalyst, usually ammonia-iron (NH3-Fe) or ammonia-vanadium (NH3-V), to catalyze the reaction of NOx with ammonia (NH3) on the catalyst surface. The nitrogen (N2) and water vapor (H2O) produced in this reaction process are harmless gases, which effectively reduce harmful emissions. The main reaction chemical formula is:

[0055] 4NO+4NH3+O2→4N2+6H2O

[0056] 6NO+4NH3→5N2+6H2O

[0057] 6NO2+8NH3→7N2+12H2O

[0058] 2NO2+4NH3+O2→3N2+6H2O

[0059] The structure of the post-treatment system 130 can adopt a conventional post-treatment system 130. Generally, the SCR denitration device includes a catalyst assembly, a reactor, and a regeneration system. The catalyst assembly is a core component, which usually includes a porous medium and a catalyst to promote the catalytic reduction reaction of ammonia and NOx. The reactor provides a contact area and an appropriate space to ensure sufficient reaction. The regeneration system is used to remove the reaction products attached to the catalyst to maintain the effect of the catalyst. The entire SCR denitration device achieves a high-efficiency emission reduction function of nitrogen oxides by reasonably matching these parts.

[0060] The urea-assisted hydrogen internal combustion engine 10 provided in the embodiment of the present invention injects urea in the intake duct 114 and utilizes the mixed combustion of urea solution and hydrogen in the cylinder 112, thereby effectively reducing the occurrence of abnormal combustion conditions such as knock and pre-ignition during the operation of the hydrogen internal combustion engine and ensuring the stable operation of the hydrogen internal combustion engine.

[0061] Figure 3 The step diagram of the hydrogen internal combustion engine control method provided by this embodiment is shown. Figure 1-Figure 3 The embodiment of the present invention further provides a hydrogen internal combustion engine control method for controlling the above-mentioned urea-assisted hydrogen internal combustion engine 10. Specifically, the above-mentioned urea-assisted hydrogen internal combustion engine 10 also has a signal processor 212, and the signal processor 212 can be regarded as being used to execute at least part of the steps of the hydrogen internal combustion engine control method.

[0062] The hydrogen internal combustion engine control method comprises:

[0063] S01: Acquire abnormal combustion signal.

[0064] The knock sensor 211 detects the combustion condition in the cylinder 112 . When abnormal combustion conditions such as knock and pre-ignition occur in the cylinder 112 , the knock sensor 211 sends an abnormal combustion signal representing the abnormal combustion condition to the signal processor 212 .

[0065] S02: During the opening phase of the intake valve 115 of the next working cycle after the abnormal combustion signal is obtained, the first urea nozzle 311 is controlled to spray urea solution into the intake passage 114 .

[0066] When an abnormal combustion signal is obtained in a certain working cycle, the first urea nozzle 311 is controlled to spray urea solution when the intake valve 115 is in an open state in the next working cycle. The spraying direction of the first urea nozzle 311 is toward the back of the intake valve 115. In this way, after the urea solution sprayed by the first urea nozzle 311 falls on the back of the intake valve 115, the urea solution can be brought into the cylinder 112 by the airflow when the intake valve 115 is opened.

[0067] Furthermore, during the operation of the hydrogen internal combustion engine, hydrogen fuel forms a flammable mixture (λ≈1) near the spark plug to ensure reliable ignition; urea solution is introduced into the peripheral lean area through a single or double injection, and the heat release process is prolonged through the slow combustion of ammonia to suppress knock.

[0068] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technology in the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A urea-assisted hydrogen internal combustion engine, comprising an internal combustion engine body, the internal combustion engine body using hydrogen as fuel; the internal combustion engine body having an intake duct, an intake valve and a cylinder, the intake duct being connected to the cylinder through an intake port, the intake valve being movably mounted at the intake port to open and close the intake port; characterized in that: The urea-assisted hydrogen internal combustion engine further comprises: a knock sensor, the knock sensor being mounted on the internal combustion engine body and being used to detect whether abnormal combustion occurs in the cylinder; and A urea injection system, wherein the urea injection system has a first urea nozzle, and the first urea nozzle is installed at the intake duct; the urea injection system is electrically connected to the knock sensor, and the first urea nozzle is used to inject urea solution into the intake duct after the knock sensor detects abnormal combustion in the cylinder.

2. The urea-assisted hydrogen internal combustion engine according to claim 1, characterized in that: The urea-assisted hydrogen internal combustion engine further includes a temperature regulating structure, and the temperature regulating structure is used to maintain the temperature of the urea solution at the first urea nozzle within a preset range.

3. The urea-assisted hydrogen internal combustion engine according to claim 2, characterized in that: The temperature regulating structure includes a liquid storage tank and a temperature regulating pipe, both ends of the temperature regulating pipe are in communication with the liquid storage tank, and the temperature regulating pipe is connected to the first urea nozzle so that the temperature of the urea solution at the first urea nozzle is maintained within the preset range through heat exchange between the liquid in the temperature regulating pipe and the first urea nozzle.

4. The urea-assisted hydrogen internal combustion engine according to claim 2, characterized in that: The urea solution sprayed from the first urea nozzle is a urea aqueous solution with a concentration of 40% to 60%, and the preset range is 28° C. to 50° C.

5. The urea-assisted hydrogen internal combustion engine according to claim 1, characterized in that: The urea nozzle sprays toward the back side of the intake valve.

6. The urea-assisted hydrogen internal combustion engine according to claim 1, characterized in that: The distance between the first urea nozzle and the air inlet is L, 50mm≤L≤100mm.

7. The urea-assisted hydrogen internal combustion engine according to claim 1, characterized in that: The urea injection system further includes a second urea nozzle, and the internal combustion engine body further includes a post-treatment system, and the second urea nozzle is used for injecting urea solution into the post-treatment system.

8. The urea-assisted hydrogen internal combustion engine according to claim 1, characterized in that: The internal combustion engine body further includes a hydrogen fuel supply system, and the hydrogen fuel supply system includes a hydrogen fuel nozzle; the hydrogen fuel nozzle is installed in the intake passage to inject hydrogen fuel into the intake passage; or, The hydrogen fuel nozzle is installed at the cylinder to inject the hydrogen fuel into the cylinder.

9. A method for controlling a hydrogen internal combustion engine, characterized in that: Used to control a urea-assisted hydrogen internal combustion engine as described in any one of claims 1 to 8; the hydrogen internal combustion engine control method comprises: Obtain abnormal combustion signals; During the intake valve opening phase of the next working cycle after the abnormal combustion signal is acquired, the first urea nozzle is controlled to spray urea solution into the intake passage.

10. The hydrogen internal combustion engine control method according to claim 9, characterized in that: During the intake valve opening stage, the first urea nozzle performs single or double injection into the intake passage.

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