Ammonia internal combustion engine jet flow combustion system and combustion control method thereof

Abstract

The invention relates to the technical field of internal combustion engines, and provides an ammonia internal combustion engine jet flow combustion system and a combustion control method thereof. The ammonia ejector is arranged on the air cylinder according to a preset inclination angle and used for ejecting liquid ammonia to the main combustion chamber for the first time in the air inlet stroke, so that ammonia mixed gas is formed in the main combustion chamber; the ammonia ejector is used for ejecting liquid ammonia to the main combustion chamber for the second time in the compression stroke, the liquid ammonia enters the jet flow chamber under the action of airflow movement to form over-concentrated ammonia mixed gas, the ammonia mixed gas is modified online to generate hydrogen in the high-temperature and high-pressure state, and the ammonia-hydrogen mixed gas is formed in the jet flow chamber; the ignition device is arranged in the jet flow chamber and used for igniting the ammonia-hydrogen mixed gas in the jet flow chamber to form flame jet flow. According to the invention, the ignition of the internal combustion engine using ammonia as fuel is stable, and the combustion process is accelerated; and a single fuel supply system is adopted, the structural arrangement of the internal combustion engine system can be simplified, and the operation cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of internal combustion engines, and in particular to an ammonia internal combustion engine jet combustion system and a combustion control method thereof. Background Art

[0002] Global environmental issues are becoming increasingly prominent, and the proposal of dual carbon goals has further aroused widespread concern about carbon emissions from internal combustion engines. From an energy perspective, the application of zero-carbon fuels is seen as a promising path. In particular, hydrogen and ammonia, as representatives of zero-carbon fuels, do not produce carbon emissions during their combustion process, providing technical support for achieving a win-win situation of high efficiency and environmental protection. Although hydrogen energy has significant advantages in volumetric energy density and flammability, there are corresponding technical and economic problems in preparation, transportation, storage, vehicle integration, power systems, and cost-effectiveness. Ammonia energy has a rich resource base. As a fuel, ammonia not only has high energy density, efficient production process, convenient transportation characteristics, low economic cost and good safety, but is also seen as a highly potential hydrogen energy carrier.

[0003] However, ammonia is inert to combustion, and in an internal combustion engine using ammonia as fuel, it is often difficult to ignite ammonia, resulting in unstable ignition. Therefore, in the related art, active fuel (such as hydrogen) is used to ignite ammonia to solve the problem of unstable ignition in an internal combustion engine using ammonia as fuel.

[0004] Although the use of hydrogen to ignite ammonia can solve the problem of unstable ignition of internal combustion engines using ammonia as fuel, the internal combustion engine requires two fuel supply systems, the system structure is cumbersome, and the control process is relatively complicated. Summary of the invention

[0005] The present invention provides an ammonia internal combustion engine jet combustion system and a combustion control method thereof, which are used to solve the above-mentioned technical defects in the prior art. It can not only stabilize the ignition of the internal combustion engine using ammonia as fuel and accelerate the combustion process; but also adopt a single fuel supply system, which can simplify the structural setting of the internal combustion engine system, reduce operating costs, and improve system efficiency and safety.

[0006] A first aspect of the present invention provides an ammonia internal combustion engine jet combustion system, comprising a main structure, an ammonia injector and an ignition device.

[0007] The main structure includes a cylinder and a piston, wherein the piston is located inside the piston, and the interior of the cylinder is configured with a main combustion chamber and a jet chamber, wherein the main combustion chamber and the jet chamber are communicated; an ammonia injector, arranged at the cylinder at a preset inclination angle, and used to inject liquid ammonia into the main combustion chamber for the first time during the intake stroke, so that the main combustion chamber forms an ammonia mixed gas; and the ammonia injector is used to inject liquid ammonia into the main combustion chamber for the second time during the compression stroke, and enter the jet chamber under the action of the airflow to form an over-concentrated ammonia mixed gas, and the ammonia mixed gas is reformed online to produce hydrogen under high temperature and high pressure, so that the jet chamber forms an ammonia-hydrogen mixed gas; The ignition device is arranged in the jet chamber and is used for igniting the ammonia-hydrogen mixed gas in the jet chamber to form a flame jet.

[0008] According to the ammonia internal combustion engine jet combustion system provided by the present invention, at the end of the compression stroke, when the piston approaches the top dead center, the ammonia injector injects liquid ammonia into the main combustion chamber for a second time, and the amount of liquid ammonia injected into the main combustion chamber for the second time by the ammonia injector is less than the amount of liquid ammonia injected into the main combustion chamber for the first time.

[0009] According to the ammonia internal combustion engine jet combustion system provided by the present invention, a reflux structure is provided on the surface of the piston, and the reflux structure is configured as follows: when the ammonia injector injects a small amount of liquid ammonia into the main combustion chamber for the second time, the liquid ammonia evaporates rapidly in a high temperature and high pressure environment to produce ammonia gas, and the ammonia gas is squeezed into the jet chamber along with the air flow, forming a locally over-concentrated ammonia mixture in the jet chamber.

[0010] According to the ammonia internal combustion engine jet combustion system provided by the present invention, the reflow structure includes a recessed area arranged on the piston surface, and the position of the recessed area corresponds to the position of the jet chamber.

[0011] According to the ammonia internal combustion engine jet combustion system provided by the present invention, the jet chamber is located in the center of the cylinder head of the cylinder, and an intake channel and an exhaust channel are symmetrically arranged along the center line of the jet chamber, and the intake channel and the exhaust channel are both connected to the main combustion chamber; The bottom of the jet chamber is provided with at least one jet hole, and the at least one jet hole is used to connect the main combustion chamber and the jet chamber.

[0012] According to the ammonia internal combustion engine jet combustion system provided by the present invention, when three jet holes are provided, one of the jet holes is located on the center line of the jet chamber, and the remaining two jet holes are symmetrically arranged along the center line of the jet chamber.

[0013] The ammonia internal combustion engine jet combustion system provided by the present invention is configured by arranging the ammonia injector in the cylinder at a preset tilt angle. The ammonia injector is used to spray liquid ammonia into the main combustion chamber for the first time during the intake stroke, so that an ammonia mixture is formed in the main combustion chamber; the ammonia injector is used to spray liquid ammonia into the main combustion chamber for the second time during the compression stroke, and enters the jet chamber under the action of the airflow to form an over-concentrated ammonia mixture. The ammonia mixture is reformed online under high temperature and high pressure to produce hydrogen, so that an ammonia-hydrogen mixture is formed in the jet chamber. This configuration can not only stabilize the ignition of the internal combustion engine using ammonia as fuel and accelerate the combustion process; but also adopt a single fuel supply system, which can simplify the structural setting of the internal combustion engine system, reduce operating costs, and improve system efficiency and safety.

[0014] The single fuel supply system means that the entire system design is simple and clear, reducing the fuel supply structure, such as additional fuel tanks, fuel pumps, filters, valves and controllers, etc., making the overall system weight lighter and more compact, which can reduce manufacturing costs and long-term operating costs.

[0015] In addition, the single fuel supply system can be better adjusted in terms of combustion efficiency and system response speed, especially in terms of fuel supply, injection, ignition and other aspects of the control is more precise, which helps to improve the engine's power performance and economy. It can also reduce the risk of fuel leakage, cross contamination, etc., especially when involving dangerous or flammable fuels. The single system reduces safety hazards and potential failure points, and improves the overall operational reliability of the system.

[0016] A second aspect of the present invention provides a combustion control method of the jet combustion system of an ammonia internal combustion engine according to any one of the above, comprising the following steps: During the intake stroke, the ammonia injector is controlled to inject a large amount of liquid ammonia into the main combustion chamber for the first time, so that an ammonia mixed gas is formed in the main combustion chamber; During the compression stroke, the ammonia injector is controlled to inject a small amount of liquid ammonia into the main combustion chamber for the second time, and the liquid ammonia enters the jet chamber under the action of the airflow to form an over-concentrated ammonia mixed gas, and the ammonia mixed gas is reformed online under high temperature and high pressure to produce hydrogen, so that the ammonia-hydrogen mixed gas is formed in the jet chamber; The ignition device is controlled to ignite the ammonia-hydrogen mixture in the jet chamber to form a flame jet, and the flame jet is sprayed into the main combustion chamber through the jet hole to ignite the ammonia mixture.

[0017] According to the combustion control method of the ammonia internal combustion engine jet combustion system provided by the present invention, the combustion control method further includes: In the first stroke cycle, during the intake stroke, the ammonia injector is controlled to inject a large amount of liquid ammonia into the main combustion chamber for the first time, so that an ammonia mixed gas is formed in the main combustion chamber; during the compression stroke, the ammonia injector is controlled to inject a small amount of liquid ammonia into the main combustion chamber for the second time, and enters the jet chamber under the action of airflow to form an over-concentrated ammonia mixed gas, and the ammonia mixed gas is reformed online under high temperature and high pressure to produce hydrogen, so that an ammonia-hydrogen mixed gas is formed in the jet chamber; In the subsequent stroke cycles, the ratio of the residual ammonia-hydrogen mixture in the jet chamber is monitored in real time. When it is determined that the ratio of the ammonia-hydrogen mixture in the jet chamber does not meet the ignition conditions, the first stroke cycle is repeated to control the ammonia injector to spray liquid ammonia into the main combustion chamber twice.

[0018] According to the combustion control method of the ammonia internal combustion engine jet combustion system provided by the present invention, the real-time monitoring of the ratio of the residual ammonia-hydrogen mixed gas in the jet chamber comprises: The residual ammonia concentration and hydrogen concentration in the jet chamber are monitored in real time, and the ratio of the ammonia-hydrogen mixed gas is determined according to the ammonia concentration and the hydrogen concentration.

[0019] The combustion control method of the jet combustion system of an ammonia internal combustion engine provided by the present invention further includes: When the first stroke cycle or the ratio of the ammonia-hydrogen mixture does not meet the ignition condition, the ignition device is controlled to perform strong ignition; In the subsequent stroke cycle, when the ratio of the ammonia-hydrogen mixture meets the ignition condition, the ignition device is controlled to perform normal ignition.

[0020] The combustion control method of the ammonia internal combustion engine jet combustion system provided by the present invention can not only stabilize the ignition of the internal combustion engine using ammonia as fuel and accelerate the combustion process; but also adopts a single fuel supply system, which can simplify the structural setting of the internal combustion engine system, reduce operating costs, and improve system efficiency and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the structure of an ammonia internal combustion engine jet combustion system provided by an embodiment of the present invention.

[0023] Figure 2 It is a flow chart of a combustion control method of an ammonia internal combustion engine jet combustion system provided by an embodiment of the present invention.

[0024] Reference numerals: 10. Main structure; 11. Cylinder; 12. Piston; 121. Reflux structure; 13. Main combustion chamber; 14. Jet chamber; 15. Intake passage; 16. Exhaust passage; 17. Jet hole; 20. Ammonia injector; 30. Ignition device. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0027] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0029] Figure 1 It is a schematic diagram of the structure of an ammonia internal combustion engine jet combustion system provided by an embodiment of the present invention.

[0030] See also Figure 1 An embodiment of the present invention provides an ammonia internal combustion engine jet combustion system, which includes a main structure, an ammonia injector 20 and an ignition device 30.

[0031] The main structure 10 includes a cylinder 11 and a piston 12. The piston 12 is located inside the cylinder 11. The piston 12 is connected to a crank-connecting rod mechanism. The rectilinear reciprocating motion of the piston 12 is converted into a rotary motion through the crankshaft, thereby driving the engine to operate. A main combustion chamber 13 and a jet chamber 14 are provided inside the cylinder 11. The main combustion chamber 13 and the jet chamber 14 are connected. The working cycle of the piston 12 moving in the cylinder 11 is divided into four stages: intake, compression, combustion (power) and exhaust.

[0032] The ammonia injector 20 is arranged on the cylinder head of the cylinder 11 at a preset tilt angle. The ammonia injector 20 is used to inject liquid ammonia into the main combustion chamber 13 for the first time during the intake stroke, so that the main combustion chamber 13 forms an ammonia mixed gas. The ammonia injector 20 is used to inject liquid ammonia into the main combustion chamber 13 for the second time during the compression stroke, and the evaporated liquid ammonia enters the jet chamber 14 under the action of the air flow to form a locally over-concentrated high-temperature ammonia mixed gas. The ammonia mixed gas is reformed online under high temperature and high pressure to produce hydrogen, so that the jet chamber 14 forms an ammonia-hydrogen mixed gas.

[0033] Here, "over-concentrated" means that the proportion of ammonia is higher relative to the amount of oxygen required for complete combustion, with the purpose of creating an ammonia-rich environment to facilitate subsequent high-temperature decomposition. Ammonia (NH3) is mixed with an appropriate amount of air or other inert carrier gas to form a highly concentrated ammonia mixture. Therefore, the jet chamber 14 realizes local online hydrogen production through the locally over-concentrated ammonia mixture, and forms an ammonia-hydrogen flame jet rich in highly active free radicals, which can effectively ignite the ammonia mixture in the main combustion chamber and improve ignition stability.

[0034] Specifically, when a partially over-concentrated ammonia mixture is formed in the jet chamber 14, the ammonia mixture is compressed to extremely high pressure and temperature during the compression stroke by the compression action of the piston 12. Under high pressure and high temperature conditions, the distance between gas molecules decreases and the kinetic energy increases, which helps to accelerate the chemical reaction of ammonia (2NH3=3H2+N2).

[0035] Since the chemical reaction of ammonia needs to be carried out at high temperature (generally over 800°C), the instantaneous high temperature generated during the compression process of the piston 12 can promote the chemical reaction. The high temperature provides sufficient energy for the decomposition of ammonia, making it easier to break bonds and release hydrogen atoms. As ammonia decomposes, nitrogen (N2) and hydrogen (H2) are produced. The hydrogen generated by the decomposition reaction is immediately mixed with the remaining undecomposed ammonia and other inert gases to form an ammonia-hydrogen mixture that can be used as an ignition agent. In order to improve the reaction efficiency, a suitable catalyst or catalyst can also be set in the jet chamber 14.

[0036] In other words, the embodiment of the present invention can prepare hydrogen online by decomposing ammonia, without providing an oxidant supply system for the jet combustion system of the ammonia internal combustion engine, thereby reducing the fuel supply structure, such as additional fuel tanks, fuel pumps, filters, valves and controllers, etc., simplifying the system setting, and enabling the entire system to adopt a single fuel supply system.

[0037] The ignition device 30 is integrated in the jet chamber 14 and is used to ignite the ammonia-hydrogen mixture in the jet chamber 14 to form a flame jet. The flame jet can be sprayed into the main combustion chamber 13 to ignite the ammonia mixture, thereby improving ignition stability and achieving zero carbon emissions.

[0038] The ignition device 30 includes a high-energy spark plug, a glow plug, a corona ignition and other powerful ignition structures. The ignition device 30 may also include a common ignition structure. For example, a high-energy spark plug may be installed at an appropriate position of the jet chamber 14 so that the high-energy spark plug can directly ignite the ammonia-hydrogen mixture in the jet chamber 14 to form a flame jet. The high-energy spark plug is usually located at the center or side of the jet chamber 14, close to the combustion zone, so as to quickly trigger the flame jet and promote the diffusion of the combustion wave.

[0039] In addition, an intake passage 15 and an exhaust passage 16 communicating with the main combustion chamber 13 are also provided on the cylinder head of the cylinder 11. The intake passage 15 includes an intake pipe and an air filter. The air filter is provided in the intake pipe, and the intake pipe is used to introduce combustion-supporting gas (such as air). The exhaust passage 16 includes an exhaust manifold and a muffler. The muffler is provided in the exhaust manifold, and the exhaust manifold is used to discharge exhaust gas after combustion.

[0040] It can be understood that the ammonia internal combustion engine jet combustion system provided by the embodiment of the present invention is to arrange the ammonia injector 20 at the cylinder 11 according to a preset tilt angle, and the ammonia injector 20 is used to inject liquid ammonia into the main combustion chamber 13 for the first time during the intake stroke, so that the main combustion chamber 13 forms an ammonia mixture. The ammonia injector 20 is used to inject liquid ammonia into the main combustion chamber 13 for the second time during the compression stroke, and the evaporated liquid ammonia enters the jet chamber 14 under the action of the air flow to form a locally over-concentrated high-temperature ammonia mixture. The ammonia mixture is reformed online under high temperature and high pressure to produce hydrogen, so that the jet chamber 14 forms an ammonia-hydrogen mixture. The ammonia-hydrogen mixture is ignited by the ignition device 30 to generate a flame jet, which is sprayed into the main combustion chamber 13 to ignite the ammonia mixture. This arrangement can not only stabilize the ignition of the internal combustion engine using ammonia as fuel and accelerate the combustion process; but also adopt a single fuel supply system, which can simplify the structural setting of the internal combustion engine system, reduce operating costs, and improve system efficiency and safety.

[0041] The single fuel supply system means that the entire system design is simple and clear, reducing the fuel supply structure, such as additional fuel tanks, fuel pumps, filters, valves and controllers, etc., making the overall system weight lighter and more compact, which can reduce manufacturing costs and long-term operating costs.

[0042] In addition, the single fuel supply system can be better adjusted in terms of combustion efficiency and system response speed, especially in terms of fuel supply, injection, ignition and other aspects of the control is more precise, which helps to improve the engine's power performance and economy. It can also reduce the risk of fuel leakage, cross contamination, etc., especially when involving dangerous or flammable fuels. The single system reduces safety hazards and potential failure points, and improves the overall operational reliability of the system.

[0043] In some embodiments of the present invention, at the end of the compression stroke, when the piston 12 approaches the top dead center, the ammonia injector 20 injects liquid ammonia into the main combustion chamber 13 for a second time, and the amount of liquid ammonia injected by the ammonia injector 20 into the main combustion chamber 13 for the second time is less than the amount of liquid ammonia injected into the main combustion chamber 13 for the first time.

[0044] When the piston 12 moves in the cylinder 11, the highest point is called the top dead center (or top dead center). When the piston 12 approaches the top dead center, the pressure in the cylinder 11 will increase significantly because the piston 12 moves upward to compress the gas in the cylinder 11 to the minimum volume. Therefore, injecting liquid ammonia at this time point at the end of the compression stroke and when the piston 12 approaches the top dead center can allow the liquid ammonia to evaporate quickly and mix with the air in a high temperature and high pressure environment, which can not only promote complete combustion, but also enter the jet chamber 14 under the action of airflow movement, forming a locally over-concentrated high-temperature ammonia mixture in the jet chamber 14.

[0045] In some embodiments of the present invention, a reflow structure 121 is provided on the surface of the piston 12. The reflow structure 121 is configured as follows: at the end of the compression stroke, when the piston 12 approaches the top dead center, when the ammonia injector 20 injects a small amount of liquid ammonia into the main combustion chamber 13 for the second time, the liquid ammonia evaporates rapidly in a high temperature and high pressure environment to produce ammonia gas, and because the reflow structure 121 generates a vortex in the main combustion chamber 13, the ammonia gas is squeezed into the jet chamber 14 with the movement of the airflow, and a locally over-concentrated ammonia mixture is formed in the jet chamber 14. The locally over-concentrated ammonia mixture reaches a high temperature and high pressure state under the compression of the piston 12, and can realize online reforming to produce hydrogen, and form an ammonia-hydrogen mixture in the jet chamber 14.

[0046] Among them, the reflux structure 121 needs to ensure that the liquid ammonia flow sprayed by the ammonia injector 20 can generate vortex or turbulence under the action of the reflux structure 121, so that the airflow enters the jet chamber 14, and forms a locally over-concentrated high-temperature ammonia mixture in the jet chamber 14, providing gas support for online reforming hydrogen production.

[0047] In some embodiments of the present invention, the reflux structure 121 may be a recessed area provided on the surface of the piston 12, and the position of the recessed area corresponds to the position of the jet chamber 14. At the end of the compression stroke, when the piston 12 is close to the top dead center, the ammonia injector 20 sprays a small amount of liquid ammonia into the main combustion chamber 13, and uses the recessed area on the surface of the piston 12 to generate airflow movement, squeezes the ammonia mixture into the jet chamber 14, and forms a locally over-concentrated ammonia mixture in the jet chamber 14. The jet chamber 14 reaches a high temperature and high pressure state under the compression of the piston 12, realizes online reforming to produce hydrogen, and forms an ammonia-hydrogen mixture in the jet chamber 14.

[0048] In addition, the reflux structure 121 can also be a blade, a guide vane or other obstacle set on the surface of the piston 12, which is used to force the fluid to bypass and generate a rotating flow, thereby causing a reflux phenomenon or a gas movement phenomenon.

[0049] In some embodiments of the present invention, the jet chamber 14 is located in the center of the cylinder head of the cylinder 11 , and the intake channel 15 and the exhaust channel 16 may be symmetrically arranged along the center line of the jet chamber 14 .

[0050] In other words, the symmetrically arranged intake channel 15 and exhaust channel 16 help create a balanced airflow in the main combustion chamber 13, avoid local airflow deflection or asymmetry, ensure that the airflow is evenly distributed throughout the main combustion chamber 13, and promote more effective mixing and combustion. The symmetrically arranged intake channel 15 and exhaust channel 16 help reduce exhaust back pressure, so that the high-temperature and high-pressure gas generated by combustion can be discharged faster and more smoothly, reducing the resistance in the main combustion chamber 13, which is beneficial to the intake process of the next cycle; at the same time, the symmetrical design helps to slow down the oscillation waves generated during the combustion process, thereby reducing noise and vibration.

[0051] In some embodiments of the present invention, at least one jet hole 17 is provided at the bottom of the jet chamber 14, and the jet chamber 14 and the main combustion chamber 13 are connected through the at least one jet hole 17, wherein the aperture of the jet hole 17 is 1 mm to 2 mm.

[0052] When three jet holes 17 are provided, one of the jet holes 17 is located on the center line of the jet chamber 14, and the other two jet holes 17 are symmetrically arranged along the center line of the jet chamber 14, and the angle between the line between the other two jet holes 17 and the ignition device 30 and the center line of the jet chamber 14 is 45 degrees. In other words, the other two jet holes 17 and the jet hole 17 located on the center line of the jet chamber 14 are evenly distributed at 45 degrees to each other.

[0053] In this way, the distributed jet holes 17 can cover a larger circulation space, ensuring that there is sufficient ammonia mixed gas in every corner of the jet chamber 14, improving the reliability of online hydrogen production, and providing a reliable basis for stable ignition. By introducing flame jets in different directions, the main combustion chamber 13 generates more turbulence, strengthens the collision and mixing between gases, improves ignition efficiency, and accelerates combustion speed.

[0054] It should be noted that the ammonia injector 20 is arranged on the cylinder head of the cylinder 11 at a preset tilt angle, in order to optimize the direction and distribution of fuel injection, ensure that the fuel can be better mixed with the air, improve the combustion efficiency and reduce emissions. The specific tilt angle is determined according to the position of the reflow structure 121 in the main combustion chamber 13, so that the liquid ammonia stream injected for the second time can enter the injection chamber 14 through the airflow generated by the reflow structure 121 after evaporation in the main combustion chamber 13.

[0055] The preset tilt angle can be 45° to 60°. Such a design can make the injected fuel form a fan-shaped or conical spray, which can cover a larger range of the main combustion chamber 13 space, while reducing the possibility of the fuel directly hitting the cylinder 11 wall to avoid the wet wall effect. The preset tilt angle can also be 15° to 20°. This preset tilt angle is used in situations where close-range concentrated injection is required, which can concentrate the fuel in the center of the main combustion chamber 13, facilitating ignition and control of the initial combustion stage.

[0056] Figure 2 It is a flow chart of a combustion control method of an ammonia internal combustion engine jet combustion system provided by an embodiment of the present invention.

[0057] See also Figure 2 The embodiment of the present invention provides a combustion control method of an ammonia internal combustion engine jet combustion system, comprising the following steps S100, S200 and S300.

[0058] Step S100: During the intake stroke, the ammonia injector 20 is controlled to inject a large amount of liquid ammonia into the main combustion chamber 13 for the first time, so that an ammonia mixture is formed in the main combustion chamber 13 .

[0059] It is understood that at the beginning of the intake stroke, the piston 12 moves downward, the volume of the main combustion chamber 13 increases, and fresh air or pre-filled gas enters the main combustion chamber 13 of the cylinder 11. At this time, the ECU (electronic control unit) determines the best injection time according to a preset program, usually triggering the ammonia injector 20 to operate within a period of time before the intake valve is about to close, ensuring that the ammonia and the incoming air have enough time to mix.

[0060] After entering the high-temperature main combustion chamber 13, ammonia quickly absorbs heat and vaporizes, and mixes with air to form an ammonia mixed gas. During the vaporization process, the latent heat of ammonia can cool the surface of the main combustion chamber 13 to prevent the main combustion chamber 13 from overheating. Auxiliary structures such as vortex chambers, bosses, slits, etc. can also be set in the main combustion chamber 13 to create vortices and turbulence to accelerate the mixing of ammonia and air.

[0061] The ammonia injector 20 is precisely controlled by an electronic control system, and a pulse width modulation (PWM) signal can be used to adjust the injection time and injection flow rate to ensure that each injection amount is accurate, thereby ensuring that the main combustion chamber 13 has sufficient ammonia and avoiding incomplete combustion or engine overcooling that may be caused by excessive supply.

[0062] The ECU continuously monitors the engine's operating conditions, such as temperature, pressure, speed, etc., and dynamically adjusts the injection parameters of the ammonia injector 20 to cope with different operating conditions, ensuring good combustion efficiency and emission control regardless of cold start or high load.

[0063] Step S200: During the compression stroke, the ammonia injector 20 is controlled to inject a small amount of liquid ammonia into the main combustion chamber 13 for the second time, and the liquid ammonia enters the jet chamber 14 under the action of the airflow to form an over-concentrated ammonia mixture. The ammonia mixture is reformed online under high temperature and high pressure to produce hydrogen, so that an ammonia-hydrogen mixture is formed in the jet chamber 14.

[0064] It is understandable that in the middle and late stages of the compression stroke, that is, before the piston 12 approaches the top dead center, the ammonia injector 20 is controlled to open again to inject a certain amount of liquid ammonia into the main combustion chamber 13. The ammonia injected this time is fully mixed with the previously formed ammonia mixed gas, the remaining air, etc. to form an ammonia mixed gas. At this time, since the piston 12 has moved upward, the volume of the main combustion chamber 13 has shrunk, and the temperature and pressure are relatively high. The ammonia injected this time evaporates quickly and enters the injection chamber 14 under the movement of the airflow to form an over-concentrated ammonia mixed gas.

[0065] Under high temperature conditions, some ammonia molecules decompose into nitrogen (N2) and hydrogen (H2), among which hydrogen becomes the more active fuel component. This process is called ammonia cracking or reforming.

[0066] Among them, the top dead center of the piston 12 can be understood as a position 1° ahead of the crankshaft angle. When it is about to reach the top dead center, the ammonia injector 20 is controlled to open again to spray a certain amount of liquid ammonia into the main combustion chamber 13. The airflow generated by the evaporation of liquid ammonia is squeezed into the jet chamber 14 along with the movement of the airflow to increase the concentration of the ammonia mixture in the jet chamber 14.

[0067] Step S300: Control the ignition device 30 to ignite the ammonia-hydrogen mixture in the jet chamber 14 to form a flame jet, and the flame jet is sprayed into the main combustion chamber 13 through the jet hole 17 to ignite the ammonia mixture.

[0068] It is understood that when the ammonia-hydrogen mixture reaches the ignition limit concentration, the ignition device 30 is controlled to ignite the ammonia-hydrogen mixture in the jet chamber 14 to form a flame jet. Due to the presence of hydrogen, the combustion speed is fast and the flame propagation ability is strong, achieving efficient ignition.

[0069] The jet hole 17 is used to guide the high-temperature and high-pressure gas after combustion to be sprayed to the center of the main combustion chamber 13 through a specific path, so as to promote the combustion of the ammonia mixture in the main combustion chamber 13 and maintain stable combustion.

[0070] In some embodiments of the present invention, the combustion control method of the ammonia internal combustion engine jet combustion system further includes: In the first stroke cycle, during the intake stroke, the ammonia injector 20 is controlled to inject a large amount of liquid ammonia into the main combustion chamber 13 for the first time, so that an ammonia mixture is formed in the main combustion chamber 13; during the compression stroke, the ammonia injector 20 is controlled to inject a small amount of liquid ammonia into the main combustion chamber 13 for the second time, and enters the jet chamber 14 under the action of airflow movement to form an over-concentrated ammonia mixture, and the ammonia mixture is reformed online under high temperature and high pressure to produce hydrogen, so that an ammonia-hydrogen mixture is formed in the jet chamber 14.

[0071] In the subsequent stroke cycles, the proportion of the high-temperature ammonia-hydrogen mixture remaining in the jet chamber 14 is monitored in real time. When it is determined that the proportion of the high-temperature ammonia-hydrogen mixture in the jet chamber 14 does not meet the ignition conditions, the ammonia injector 20 is controlled to spray liquid ammonia into the main combustion chamber 13 twice in the first stroke cycle.

[0072] In some embodiments of the present invention, real-time monitoring of the ratio of the residual high-temperature ammonia-hydrogen mixed gas in the jet chamber 14 includes: The residual ammonia concentration and hydrogen concentration in the jet chamber 14 are detected in real time, and the ratio of the high-temperature ammonia-hydrogen mixed gas is determined according to the ammonia concentration and the hydrogen concentration.

[0073] It is understood that a gas sensor, such as an infrared spectrometer, a mass spectrometer or a dedicated NH 3 / H 2 sensor, may be installed near the jet chamber 14 to continuously monitor the concentrations of ammonia (NH 3 ) and hydrogen (H 2 ).

[0074] The gas sensor transmits the collected data to the ECU (electronic control unit). The ECU's built-in algorithm processes the information from the gas sensor, calculates the actual ratio of ammonia and hydrogen in the current mixture, and the deviation from the set ideal ratio, determines whether it is necessary to continue repeating the first stroke cycle, and controls the ammonia injector 20 to spray liquid ammonia into the main combustion chamber 13 twice.

[0075] When it is determined that the ratio of the residual ammonia-hydrogen mixture in the jet chamber 14 meets the ignition condition, the ignition device 30 can be directly controlled to ignite in the subsequent stroke cycle. When it is determined that the ratio of the residual ammonia-hydrogen mixture in the jet chamber 14 does not meet the ignition condition, the ammonia injector 20 is first controlled to spray liquid ammonia into the main combustion chamber 13 twice, so that the ratio of the ammonia-hydrogen mixture in the jet chamber 14 meets the ignition condition, and then the ignition device 30 is controlled to ignite to ensure stable and reliable ignition.

[0076] It should be noted that the ECU will set upper and lower safety concentration limits for ammonia and hydrogen. Once these thresholds are exceeded or fallen below, immediate measures will be taken, such as adjusting the injection amount or stopping a single injection, to avoid unsafe combustion conditions.

[0077] In some embodiments of the present invention, the combustion control method of the ammonia internal combustion engine jet combustion system further includes: In the first stroke cycle or when the ratio of the ammonia-hydrogen mixture does not meet the ignition conditions, the ignition device 30 is controlled to perform strong ignition; in subsequent stroke cycles, and when the ratio of the ammonia-hydrogen mixture meets the ignition conditions, the ignition device 30 is controlled to perform normal ignition.

[0078] It is understandable that it is difficult to achieve stable ignition in the first cycle of engine startup and the first cycle after all the residual ammonia-hydrogen mixture in the jet chamber 14 is consumed. Therefore, it is necessary to use powerful ignition components such as high-energy spark plugs, glow plugs, corona ignition, etc. to achieve the first ignition.

[0079] In the subsequent cycles, due to the presence of residual high-temperature ammonia-hydrogen mixture, it is no longer necessary to use high-energy ignition components, and ordinary spark ignition can be used. Specific implementation methods include but are not limited to: (1) using the electronic control system to adjust the charging energy of the spark plug ignition coil to achieve the switching of the high-energy spark plug and ordinary spark plug states. (2) only using the glow plug to work continuously; (3) using the glow plug and ordinary spark plug at the same time, switching the use mode through the control system, using the glow plug to achieve ignition in the first cycle, and using the ordinary spark plug in the subsequent cycles until the residual ammonia-hydrogen mixture in the jet chamber 14 is completely consumed, and the glow plug is started when the double injection strategy is used again.

[0080] Among them, high-energy spark plugs, glow plugs, etc. can be replaced with other strong ignition devices. The purpose is to use them together with the above two injection strategies in the first cycle of engine startup and the first cycle after all the residual ammonia-hydrogen mixture in the jet chamber 14 is consumed, so as to achieve stable ignition in the first cycle.

[0081] The innovative features of the ammonia internal combustion engine jet combustion system and combustion control method provided by the present invention are: In the first cycle of the internal combustion engine, the ammonia injector 20 adopts a two-injection strategy. The first injection occurs during the intake stroke, and a large amount of ammonia is ejected. The purpose is to form an ammonia mixture in the cylinder 11. The ammonia mixture can be a stoichiometric ammonia mixture or a lean ammonia mixture to achieve higher thermal efficiency. The second injection occurs in the late stage of the compression stroke. When the piston 12 approaches the top dead center, the amount of ammonia ejected is small. Through the airflow movement generated by the concave area on the piston 12, a small amount of ammonia mixture is squeezed into the jet chamber 14, forming a locally over-concentrated high-temperature ammonia mixture in the jet chamber 14. The ammonia mixture is reformed online under high temperature and high pressure to produce hydrogen, so that the jet chamber forms an ammonia-hydrogen mixture. After the ammonia-hydrogen mixture is ignited by the high-energy spark plug, it is ejected into the flame jet to the main combustion chamber 13 through the jet hole 17, further igniting the ammonia mixture in the main combustion chamber 13.

[0082] During the intake stroke, when the ammonia injector 20 injects liquid ammonia for the first time, the injection pressure and injection duration of the ammonia injector 20 can be reasonably controlled to form an ammonia mixed gas in the main combustion chamber 13. That is, during the intake stroke, the purpose of injecting liquid ammonia is to form an ammonia mixed gas in the entire main combustion chamber 13. At this time, the volume of the main combustion chamber 13 is relatively large, and more liquid ammonia needs to be injected. For example, the injection pressure can be 10kPa, and the injection duration can be 1ms. Among them, the injection pressure and injection duration depend on the engine working condition and can be changed according to the specific working condition.

[0083] At the end of the compression stroke, when the ammonia injector 20 injects liquid ammonia for the second time, the injection pressure, injection duration and injection timing of the liquid ammonia can be reasonably controlled so that the jet chamber 14 forms an ammonia-hydrogen mixture with a certain proportion of hydrogen before ignition, so that an ammonia-hydrogen flame jet can be formed under the action of ignition by the ignition device 30, and the ammonia-hydrogen flame jet is injected into the main combustion chamber 13 through the jet hole 17 to ignite the ammonia mixture in the main combustion chamber 13. That is, the purpose of the second injection of liquid ammonia near the top dead center of the piston 12 is to use the concave area on the surface of the piston 12 to form an airflow movement, and the airflow movement rolls the sprayed ammonia into the jet chamber 14 to form a locally over-concentrated ammonia mixture, and the locally over-concentrated ammonia mixture under high temperature and high pressure is reformed online to produce hydrogen (for example, compressed to 1100 K, 30 bar top dead center pressure can produce hydrogen online), and an ammonia-hydrogen mixture is formed in the jet chamber 14. At this time, the amount of liquid ammonia injected does not need to be too large, for example, the injection pressure can be 5kPa, the injection duration can be 0.1ms, and the injection pressure and duration are both reduced.

[0084] Since online reforming is achieved in the jet chamber 14 to produce hydrogen, and further form an ammonia-hydrogen mixture, a flame jet is formed after ignition by a powerful ignition device such as a high-energy spark plug, a glow plug, or a corona ignition. The flame jet is sprayed into the main combustion chamber 13 to ignite the ammonia mixture in the main combustion chamber 13. This can not only obtain stable ignition performance, but also accelerate the combustion process, improve thermal efficiency, and achieve zero carbon emissions. It has significant progress in achieving energy conservation and emission reduction of internal combustion engines and solving the problem of carbon neutrality. At the same time, only a single fuel supply system is used, which makes the structural setting of the internal combustion engine system simple, which can reduce operating costs, and improve system efficiency and safety.

[0085] In the first cycle, the concentrated ammonia mixture is reformed into hydrogen online under high temperature and high pressure conditions to form a hydrogen-ammonia mixture that is compressed and ignited. Theoretically, hydrogen will remain in the jet chamber 14. Due to the existence of the jet chamber 14, according to the theory of exhaust gas recirculation (EGR), the exhaust gas cannot be completely discharged. Then in the next cycle, the jet chamber 14 only needs to spray ammonia to form an ammonia-hydrogen mixture.

[0086] Therefore, in the first cycle, a two-injection strategy is used to form a stable jet ignition. In the subsequent cycles, a certain proportion of high-temperature ammonia-hydrogen mixture still remains in the jet chamber 14, that is, a locally over-concentrated high-temperature ammonia-hydrogen mixture remains, which can achieve stable jet ignition in the subsequent cycles. Therefore, the two-injection strategy can be omitted in the subsequent cycles, and only the first injection can be retained to achieve stable jet ignition. After several cycles, when the ammonia concentration and hydrogen concentration in the residual ammonia-hydrogen mixture in the jet chamber 14 decrease and it is difficult to meet the ignition conditions, the two-injection strategy is reactivated, and this reciprocating process can ensure that the internal combustion engine system can be stably ignited using a single ammonia fuel and its supply system.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ammonia internal combustion engine jet combustion system, characterized in that: include: The main structure includes a cylinder and a piston, wherein the piston is located inside the piston, and the interior of the cylinder is configured with a main combustion chamber and a jet chamber, wherein the main combustion chamber and the jet chamber are communicated; an ammonia injector, arranged at the cylinder at a preset inclination angle, the ammonia injector being used to inject liquid ammonia into the main combustion chamber for the first time during the intake stroke so as to form an ammonia mixed gas in the main combustion chamber; The ammonia injector is used to inject liquid ammonia into the main combustion chamber for the second time during the compression stroke, and the liquid ammonia enters the jet chamber under the action of the airflow to form an over-concentrated ammonia mixed gas, and the ammonia mixed gas is reformed online under high temperature and high pressure to produce hydrogen, so that the ammonia-hydrogen mixed gas is formed in the jet chamber; The ignition device is arranged in the jet chamber and is used for igniting the ammonia-hydrogen mixed gas in the jet chamber to form a flame jet.

2. The ammonia internal combustion engine jet combustion system according to claim 1, characterized in that: At the end of the compression stroke, when the piston approaches the top dead center, the ammonia injector injects liquid ammonia into the main combustion chamber for the second time, and the amount of liquid ammonia injected into the main combustion chamber for the second time is less than the amount of liquid ammonia injected into the main combustion chamber for the first time.

3. The ammonia internal combustion engine jet combustion system according to claim 1, characterized in that: A reflux structure is provided on the surface of the piston, and the reflux structure is configured as follows: when the ammonia injector injects a small amount of liquid ammonia into the main combustion chamber for the second time, the liquid ammonia evaporates rapidly in a high temperature and high pressure environment to produce ammonia gas, and the ammonia gas moves into the jet chamber with the air flow, forming a locally over-concentrated ammonia mixture in the jet chamber.

4. The ammonia internal combustion engine jet combustion system according to claim 3, characterized in that: The reflux structure includes a recessed area arranged on the surface of the piston, and the position of the recessed area corresponds to the position of the jet chamber.

5. The ammonia internal combustion engine jet combustion system according to claim 1, characterized in that: The jet chamber is located in the center of the cylinder head of the cylinder, and an intake channel and an exhaust channel are symmetrically arranged along the center line of the jet chamber, and the intake channel and the exhaust channel are both connected to the main combustion chamber; The bottom of the jet chamber is provided with at least one jet hole, and the at least one jet hole is used to connect the main combustion chamber and the jet chamber.

6. The ammonia internal combustion engine jet combustion system according to claim 5, characterized in that: In the case where three jet holes are provided, one of the jet holes is located at the center line of the jet chamber, and the remaining two jet holes are symmetrically arranged along the center line of the jet chamber.

7. A combustion control method for an ammonia internal combustion engine jet combustion system according to any one of claims 1 to 6, characterized in that: The steps include: During the intake stroke, the ammonia injector is controlled to inject a large amount of liquid ammonia into the main combustion chamber for the first time, so that an ammonia mixed gas is formed in the main combustion chamber; During the compression stroke, the ammonia injector is controlled to inject a small amount of liquid ammonia into the main combustion chamber for the second time, and the liquid ammonia enters the jet chamber under the action of the airflow to form an over-concentrated ammonia mixed gas, and the ammonia mixed gas is reformed online under high temperature and high pressure to produce hydrogen, so that the ammonia-hydrogen mixed gas is formed in the jet chamber; The ignition device is controlled to ignite the ammonia-hydrogen mixture in the jet chamber to form a flame jet, and the flame jet is sprayed into the main combustion chamber through the jet hole to ignite the ammonia mixture.

8. The combustion control method of the jet combustion system of an ammonia internal combustion engine according to claim 7, characterized in that: The combustion control method further comprises: In the first stroke cycle, during the intake stroke, the ammonia injector is controlled to inject a large amount of liquid ammonia into the main combustion chamber for the first time, so that an ammonia mixed gas is formed in the main combustion chamber; during the compression stroke, the ammonia injector is controlled to inject a small amount of liquid ammonia into the main combustion chamber for the second time, and enters the jet chamber under the action of airflow to form an over-concentrated ammonia mixed gas, and the ammonia mixed gas is reformed online under high temperature and high pressure to produce hydrogen, so that an ammonia-hydrogen mixed gas is formed in the jet chamber; In the subsequent stroke cycles, the ratio of the residual ammonia-hydrogen mixture in the jet chamber is monitored in real time. When it is determined that the ratio of the ammonia-hydrogen mixture in the jet chamber does not meet the ignition conditions, the first stroke cycle is repeated to control the ammonia injector to spray liquid ammonia into the main combustion chamber twice.

9. The combustion control method of the jet combustion system of an ammonia internal combustion engine according to claim 8, characterized in that: The real-time monitoring of the ratio of the residual ammonia-hydrogen mixed gas in the jet chamber comprises: The residual ammonia concentration and hydrogen concentration in the jet chamber are monitored in real time, and the ratio of the ammonia-hydrogen mixed gas is determined according to the ammonia concentration and the hydrogen concentration.

10. The combustion control method of the jet combustion system of an ammonia internal combustion engine according to claim 8, characterized in that: Also includes: When the first stroke cycle or the ratio of the ammonia-hydrogen mixture does not meet the ignition condition, the ignition device is controlled to perform strong ignition; In the subsequent stroke cycle, when the ratio of the ammonia-hydrogen mixture meets the ignition condition, the ignition device is controlled to perform normal ignition.

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