Compression ignition type ammonia-diesel dual-fuel engine

Abstract

The invention provides a compression ignition type ammonia-diesel oil dual-fuel engine, which relates to the technical field of engines, and comprises a cylinder body, a cylinder cover and a piston, a combustion chamber is defined between the cylinder body and the cylinder cover, and the piston is configured to reciprocate along the axial direction of the cylinder body. The ammonia injector is installed on the cylinder cover and used for injecting ammonia fuel, a first injection hole set, a second injection hole set and a third injection hole set which are distributed in the axial direction are formed in the ammonia injector, the first injection hole set faces a high-turbulence kinetic energy area on the upper portion of the combustion chamber, and the second injection hole set faces a middle-turbulence kinetic energy area in the middle of the combustion chamber; and the third spray hole group faces a low-turbulent-energy area at the lower part of the combustion chamber. A diesel nozzle is mounted to the cylinder head for injecting diesel, and a piston is adapted for compression ignition of diesel to ignite ammonia fuel.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and more particularly to a compression-ignition ammonia-diesel dual-fuel engine. Background Art

[0002] Ammonia (NH3), a zero-carbon fuel, is a key candidate for future energy transitions due to its high energy density (18.6 MJ / kg) and established storage and transportation infrastructure. Unlike traditional carbon-based fuels, ammonia combustion releases only nitrogen and water, making it particularly suitable for high-emission sectors such as shipping and power generation that are difficult to electrify. However, widespread adoption of ammonia fuel faces multiple challenges: First, ammonia's slow combustion rate (laminar flame speed is only one-fifth that of gasoline) and high ignition temperature (651°C) result in low combustion efficiency. Second, ammonia combustion readily generates nitrogen oxides (NOx), whose emissions can reach more than twice those of diesel engines, necessitating the use of post-treatment technologies. Third, ammonia's toxicity and corrosiveness to metals require specialized protective designs for storage and transportation systems. Currently, researchers are improving ammonia's combustion characteristics through methods such as hydrogen blending and optimizing combustion chamber structure. However, achieving high thermal efficiency while maintaining low emissions remains a core technical challenge.

[0003] Ammonia-fueled engines are a new type of power plant, with technical approaches categorized into spark ignition (SI), compression ignition (CI), and dual-fuel modes. Spark ignition engines face challenges such as unstable flame propagation and large cycle fluctuations. Due to ammonia's high auto-ignition temperature (>900°C), compression ignition engines also require a high compression ratio (>35:1) or the addition of a highly active fuel (such as diesel) for ignition. The ammonia-diesel dual-fuel engine is a hybrid system that combines the zero-carbon properties of ammonia with the high combustion activity of diesel, aiming to achieve low carbon emissions while ensuring stable engine operation. In this system, ammonia serves as the primary fuel (accounting for 50% to 90% of the energy) and is supplied through the intake manifold or injection system. A small amount of diesel (10% to 50%) is ignited through high-pressure in-cylinder injection. The high cetane number of diesel fuel promotes the combustion of ammonia, thereby overcoming the difficulties of pure ammonia ignition and slow combustion.

[0004] In related direct-injection engine technologies, there have been few improvements to the injection method of ammonia fuel, and the ignition success rate, combustion stability and substitution rate (i.e., the proportion of ammonia fuel in the mixed fuel) of ammonia fuel still need to be further improved. These are closely related to the diffusion and distribution of ammonia fuel in the combustion chamber. Therefore, how to further optimize the injection system of the ammonia-diesel dual-fuel engine and improve the ignition stability and ammonia fuel substitution rate has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] In view of this, the present invention provides a compression ignition ammonia-diesel dual-fuel engine, which can reduce the ignition temperature of the engine combustion chamber, improve the ignition stability of the ammonia-diesel dual-fuel, and reduce nitrogen oxide emissions.

[0006] In order to achieve the above-mentioned objectives, the present invention provides a compression-ignition ammonia-diesel dual-fuel engine, comprising a cylinder block, a cylinder head and a piston, wherein a combustion chamber is defined between the cylinder block and the cylinder head, and the piston is configured to reciprocate along the axial direction of the cylinder block. The engine also comprises: an ammonia injector, mounted on the cylinder head and used for injecting ammonia fuel, the ammonia injector being formed with a first spray hole group, a second spray hole group and a third spray hole group arranged along the axial direction, the first spray hole group being directed toward a high turbulent kinetic energy region at the upper part of the combustion chamber, the second spray hole group being directed toward a medium turbulent kinetic energy region at the middle part of the combustion chamber, and the third spray hole group being directed toward a low turbulent kinetic energy region at the lower part of the combustion chamber; a diesel nozzle, mounted on the cylinder head and used for injecting diesel, and the piston being suitable for compression igniting diesel to ignite the ammonia fuel.

[0007] According to an embodiment of the present invention, the ammonia fuel flow rate of the first injection hole group is greater than the ammonia fuel flow rate of the second injection hole group, and the ammonia fuel flow rate of the second injection hole group is greater than the ammonia fuel flow rate of the third injection hole group.

[0008] According to an embodiment of the present invention, the first spray hole group includes: a first middle spray hole; two first spray holes, respectively located on both sides of the first middle spray hole along the circumferential direction, and the aperture of the first spray holes is smaller than the aperture of the first middle spray hole.

[0009] According to an embodiment of the present invention, the second spray hole group includes: a second middle spray hole; two second spray holes, respectively located on both sides of the second middle spray hole along the circumferential direction, and the aperture of the second spray holes is smaller than the aperture of the second middle spray hole.

[0010] According to an embodiment of the present invention, the third nozzle hole group includes at least two third nozzle holes.

[0011] According to an embodiment of the present invention, the diesel nozzle and the ammonia injector are spaced apart in the circumferential direction, and the diesel nozzle is located on a side of the ammonia injector away from the ammonia fuel and injects diesel toward the ammonia fuel.

[0012] According to an embodiment of the present invention, the diesel nozzle is provided with a first fuel injection hole, a second fuel injection hole and a third fuel injection hole arranged in an axial direction. The oil beam sprayed from the first fuel injection hole is mixed with the ammonia fuel mist beam sprayed from the first nozzle group in a high turbulent kinetic energy area, the oil beam sprayed from the second fuel injection hole is mixed with the ammonia fuel mist beam sprayed from the second nozzle group in a medium turbulent kinetic energy area, and the oil beam sprayed from the third fuel injection hole is mixed with the ammonia fuel mist beam sprayed from the third nozzle group in a low turbulent kinetic energy area.

[0013] According to an embodiment of the present invention, the diesel flow rate of the first fuel injection hole is greater than the diesel flow rate of the second fuel injection hole, and the diesel flow rate of the second fuel injection hole is greater than the diesel flow rate of the third fuel injection hole.

[0014] According to an embodiment of the present invention, the above-mentioned first oil injection hole includes: a first middle oil injection hole; two first side oil injection holes, which are respectively located on both sides of the above-mentioned first middle oil injection hole along the circumferential direction, and the aperture of the above-mentioned first side oil injection holes is smaller than the aperture of the above-mentioned first middle oil injection hole.

[0015] According to an embodiment of the present invention, the above-mentioned second oil spray hole includes: a second middle oil spray hole; two second side oil spray holes, which are respectively located on both sides of the above-mentioned second middle oil spray hole along the circumferential direction, and the aperture of the above-mentioned second side oil spray holes is smaller than the aperture of the above-mentioned second middle oil spray hole.

[0016] Preferably, at least two of the third oil injection holes are arranged at intervals along the circumferential direction.

[0017] The compression-ignition ammonia-diesel dual-fuel engine provided by the present invention simultaneously injects ammonia fuel and diesel into the combustion chamber, so that the diesel is first compression-ignited by the piston and then ignites the ammonia fuel, thereby reducing the ignition temperature in the combustion chamber. The ammonia fuel is then injected into different turbulent kinetic energy areas in the combustion chamber, so that the ammonia fuel is distributed more evenly in the combustion chamber, thereby improving the diesel ignition efficiency and the stability of the combustion process, and reducing the emission of nitrogen oxides. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a cross-sectional schematic diagram of a compression ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention;

[0019] Figure 2 is a top view of a compression ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention;

[0020] Figure 3 is a top view of an ammonia injector for a compression-ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention;

[0021] Figure 4 1 is a top view of a diesel nozzle of a compression ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention;

[0022] Figure 5 4 is a cross-sectional schematic diagram of an ammonia injector for a compression-ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention.

[0023] In the drawings, the meanings of the reference numerals are as follows:

[0024] 1. Ammonia injector;

[0025] 11. The first nozzle group;

[0026] 111. first middle spray hole;

[0027] 112. First spray hole;

[0028] 12. Second nozzle group;

[0029] 121, second middle spray hole;

[0030] 122, second spray hole;

[0031] 13. The third nozzle group;

[0032] 131, third nozzle;

[0033] 14. Fourth nozzle;

[0034] 15. Housing;

[0035] 16. Core;

[0036] 2. Diesel nozzle;

[0037] 21. First fuel injection hole;

[0038] 211, first middle oil injection hole;

[0039] 212, first side oil injection hole;

[0040] 22. Second fuel injection hole;

[0041] 221, second middle oil injection hole;

[0042] 222, second side oil injection hole;

[0043] 23. The third fuel injection hole;

[0044] 3. Cylinder body;

[0045] 4. Cylinder head;

[0046] 5. Piston. DETAILED DESCRIPTION

[0047] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0048] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0049] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0050] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0051] Figure 1 is a cross-sectional schematic diagram of a compression ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention, Figure 2 FIG. 1 is a top view of a compression-ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention.

[0052] An exemplary embodiment of the present invention provides a compression ignition ammonia-diesel dual fuel engine, such as Figures 1 to 2 As shown, the engine comprises a cylinder block 3, a cylinder head 4, and a piston 5. A combustion chamber is defined between the cylinder block 3 and the cylinder head 4, and the piston 5 is configured to reciprocate along the axial direction of the cylinder block 3. It also includes an ammonia injector 1 and a diesel nozzle 2. The ammonia injector 1 is mounted on the cylinder head 4 and is used to inject ammonia fuel. Ammonia injector 1 is formed with a first nozzle group 11, a second nozzle group 12, and a third nozzle group 13 arranged along the axial direction. The first nozzle group faces the high turbulent kinetic energy region at the top of the combustion chamber, the second nozzle group 12 faces the medium turbulent kinetic energy region in the middle of the combustion chamber, and the third nozzle group 13 faces the low turbulent kinetic energy region at the bottom of the combustion chamber. The diesel nozzle 2 is mounted on the cylinder head 4 and is used to inject diesel fuel. The piston 5 is suitable for compression igniting the diesel fuel to ignite the ammonia fuel.

[0053] In the combustion chamber, the upper space has a high turbulent kinetic energy (TKE) due to its proximity to the ammonia injector 1, diesel nozzle 2, air intake, and compression ignition point. Therefore, it is a high turbulent kinetic energy region. The turbulence in the high turbulent kinetic energy region diffuses downstream (i.e., the middle space of the combustion chamber), where the energy gradually dissipates and the turbulent kinetic energy decreases. Therefore, it is a medium turbulent kinetic energy region. The shear effect of the cylinder wall 3 further suppresses the development of turbulence, and small-scale eddies further lose energy due to viscous dissipation. Therefore, it is a low turbulent kinetic energy region.

[0054] Because ammonia fuel has a high auto-ignition temperature, reaching above 900°C, compression ignition requires a compression ratio of 35 or higher to ensure a successful compression ignition. This implementation simultaneously injects ammonia fuel and diesel into the combustion chamber, causing the diesel to be compression-ignited first, followed by the ammonia fuel, lowering the ignition temperature of the mixed fuel (ammonia fuel and diesel). Furthermore, by injecting ammonia fuel into different turbulent kinetic energy zones within the combustion chamber, the ammonia fuel is more evenly distributed within the combustion chamber, improving diesel ignition efficiency and combustion stability, while also reducing nitrogen oxide emissions.

[0055] More specifically, during the compression stroke, piston 5 ascends from bottom dead center. When it reaches near top dead center, ammonia injector 1 and diesel nozzle 2 begin spraying fuel. Diesel nozzle 2 may begin spraying fuel slightly before or simultaneously with ammonia injector 1. As piston 5 continues to ascend, the diesel fuel is compression-ignited first, which in turn ignites the ammonia fuel, pushing piston 5 downward and entering the power stroke.

[0056] In an exemplary embodiment, the ammonia fuel flow rate of the first injection hole group 11 is greater than the ammonia fuel flow rate of the second injection hole group 12 , and the ammonia fuel flow rate of the second injection hole group 12 is greater than the ammonia fuel flow rate of the third injection hole group 13 .

[0057] In such an embodiment, the amount of ammonia fuel to be injected in the target area is adjusted accordingly according to the difference in turbulent kinetic energy in different areas. For example, in areas with higher turbulent kinetic energy, the flow shear is strong, the vortex size is small, the mixing rate is fast, and the corresponding ammonia fuel equivalence ratio is higher, so as to promote ignition and reduce nitrogen oxide emissions.

[0058] In some optional embodiments, the ammonia fuel flow ratio of the first nozzle group 11, the second nozzle group 12 and the third nozzle group 13 is approximately 2:1.5:1. Taking the first nozzle group 11 as an example, the ammonia fuel flow rate is achieved by adjusting the number of holes it contains or the aperture of the holes.

[0059] Figure 3 FIG. 1 is a top view of an ammonia injector for a compression-ignition ammonia-diesel dual-fuel engine according to an exemplary embodiment of the present invention.

[0060] In an exemplary embodiment, Figure 3 As shown, the first spray hole group 11 includes a first middle spray hole 111 and two first spray holes 112 . The two first spray holes 112 are respectively located on both sides of the first middle spray hole 111 along the circumferential direction, and the aperture of the first spray hole 112 is smaller than that of the first middle spray hole 111 .

[0061] In such an embodiment, the ammonia fuel sprayed from the large-aperture first middle nozzle 111 has a large flow rate and high injection energy to match the high-temperature and high-turbulent kinetic energy zone to form a rich fuel environment, while the first nozzles 112 on both sides adopt a small aperture to avoid excessive ammonia fuel accumulation and the escape of unburned ammonia.

[0062] According to the embodiments of the present disclosure, Figure 3 As shown, the second spray hole group 12 includes a second middle spray hole 121 and two second spray holes 122 . The two second spray holes 122 are respectively located on both sides of the second middle spray hole 121 along the circumferential direction, and the aperture of the second spray hole 122 is smaller than that of the second middle spray hole 121 .

[0063] In this embodiment, similar to the first nozzle group 11, the large-diameter second intermediate nozzles 121 spray ammonia fuel at a high flow rate and high injection energy, matching the high-temperature, high-turbulent kinetic energy zone to create a fuel-rich environment. It should be noted that the high-turbulent kinetic energy zone targeted by the second intermediate nozzles 121 is actually the high-turbulent kinetic energy portion of the intermediate turbulent kinetic energy region of the entire combustion chamber, rather than the high-turbulent kinetic energy region described in the above embodiment. The second nozzles 122 on both sides have small diameters to prevent excess ammonia fuel accumulation and the escape of unburned ammonia.

[0064] In some optional embodiments, taking the first nozzle group 11 as an example, the two first nozzles 112 are respectively located on both sides of the first middle nozzle 111, and the angle of the sprayed ammonia fuel mist beam, or the first angle between the axis of the first nozzle 112 and the axis of the first middle nozzle 111 is between 20° and 40°, and preferably 30°.

[0065] Furthermore, taking the second nozzle group 12 as an example, the two second nozzles 122 are respectively located on both sides of the second middle nozzle 121, and the angle of the sprayed ammonia fuel mist beam, or the second angle between the axis of the second nozzle 122 and the axis of the second middle nozzle 121 is between 35° and 55°, preferably different from the first angle, for example 45°, to further improve the uniformity of the ammonia fuel distribution.

[0066] According to the embodiments of the present disclosure, Figure 3 As shown, the third spray hole group 13 includes at least two third spray holes 131 .

[0067] In such an embodiment, since the third nozzle group 13 faces the low turbulent kinetic energy area, the ammonia fuel equivalence ratio in this area is appropriately reduced to prevent ammonia escape and avoid the accidental generation of thermal nitrogen oxides due to excessive temperature in the low turbulent kinetic energy area.

[0068] In some optional embodiments, the number of the third injection holes 131 is preferably two, or the number of the third injection holes 131 is increased while the apertures of the third injection holes 131 are reduced to maintain the equivalence ratio.

[0069] In an exemplary embodiment, Figure 2 As shown, the diesel nozzle 2 and the ammonia injector 1 are spaced apart in the circumferential direction, and the diesel nozzle 2 is located on the side of the ammonia injector 1 away from the ammonia fuel, and injects diesel toward the ammonia fuel.

[0070] In such an embodiment, the directions of the first spray hole group 11, the second spray hole group 12 and the third spray hole group 13 of the ammonia injector 1 are roughly in line with the vortex direction in the cylinder body 3, that is, the circumferential direction of the cylinder body 3. Taking the direction of the ammonia fuel injection by the ammonia injector 1 as a reference, the diesel nozzle 2 is located upstream of the ammonia injector 1, and the injection direction of the diesel nozzle 2 is mainly to spray the ammonia fuel.

[0071] In some other embodiments, two ammonia injectors 1 and two diesel nozzles 2 are provided. Taking the ammonia injector 1 as an example, the two ammonia injectors 1 are symmetrically arranged about the center of the cylinder body 3, so that the two ammonia injectors 1 cooperate to inject ammonia fuel and better conform to the direction of the vortex.

[0072] According to the embodiments of the present disclosure, Figure 1 and Figure 2 As shown, the diesel nozzle 2 is provided with a first fuel injection hole 21, a second fuel injection hole 22 and a third fuel injection hole 23 arranged in the axial direction. The oil beam sprayed from the first fuel injection hole 21 is mixed with the ammonia fuel mist beam sprayed from the first nozzle group 11 in a high turbulent kinetic energy area, the oil beam sprayed from the second fuel injection hole 22 is mixed with the ammonia fuel mist beam sprayed from the second nozzle group 12 in a medium turbulent kinetic energy area, and the oil beam sprayed from the third fuel injection hole 23 is mixed with the ammonia fuel mist beam sprayed from the third nozzle group 13 in a low turbulent kinetic energy area.

[0073] In such an embodiment, the first spray hole group 11 of the ammonia injector 1 and the first spray hole 21 of the diesel nozzle 2 are at the same horizontal plane, the second spray hole group 12 and the second spray hole 22 are at the same horizontal plane, and the third spray hole group 13 and the third spray hole 23 are at the same horizontal plane. By injecting diesel in a similar injection method to ammonia fuel, the mixing of diesel and ammonia fuel is further promoted, the mixing uniformity is improved, and the ammonia fuel is better ignited.

[0074] Further according to an embodiment of the present disclosure, the diesel flow rate of the first injection hole 21 is greater than the diesel flow rate of the second injection hole 22 , and the diesel flow rate of the second injection hole 22 is greater than the diesel flow rate of the third injection hole 23 .

[0075] In such an embodiment, since the first injection hole 21, the second injection hole 22 and the third injection hole 23 are also directed towards the high turbulent kinetic energy area, the medium turbulent kinetic energy area and the low turbulent kinetic energy area in the cylinder body 3 respectively, based on similar principles, for the area with higher turbulent kinetic energy, the injection amount of diesel is correspondingly higher, so as to ignite the ammonia fuel more effectively.

[0076] In some optional embodiments, the diesel flow ratio of the first injection hole 21, the second injection hole 22 and the third injection hole 23 is approximately 1.5:1.25:1, and the diesel flow rate is achieved by adjusting the number of holes contained therein or the aperture of the holes.

[0077] Figure 4 FIG. 1 is a top view of a diesel nozzle of a compression-ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention.

[0078] In an exemplary embodiment, Figure 4 As shown, the first fuel injection hole 21 includes a first middle fuel injection hole 211 and two first side fuel injection holes 212. The two first side fuel injection holes 212 are respectively located on both sides of the first middle fuel injection hole 211 along the circumferential direction, and the aperture of the first side fuel injection holes 212 is smaller than the aperture of the first middle fuel injection hole 211.

[0079] In this embodiment, the large-diameter first middle injection hole 211 sprays diesel with a high flow rate and high injection energy, matching the high-equivalence ratio ammonia fuel sprayed from the first middle injection hole 111. The first side injection holes 212 on both sides have smaller diameters and relatively lower diesel flow rates, but their placement allows them to cover a wider range, enhance mixing efficiency, and achieve a more uniform mixing of ammonia fuel and diesel.

[0080] According to the embodiments of the present disclosure, Figure 4 As shown, the second fuel injection hole 22 includes a second middle fuel injection hole 221 and two second side fuel injection holes 222. The two second side fuel injection holes 222 are respectively located on both sides of the second middle fuel injection hole 221 along the circumferential direction, and the aperture of the second side fuel injection hole 222 is smaller than the aperture of the second middle fuel injection hole 221.

[0081] In this embodiment, similar to the first injection hole 21, the large-diameter second middle injection hole 221 sprays a large diesel flow rate and high injection energy to match the high-equivalence ratio ammonia fuel sprayed from the second middle injection hole 121. The second side injection holes 222 on both sides have smaller diameters and relatively lower diesel flow rates, but their placement allows them to cover a wider range, enhance mixing efficiency, and achieve a more uniform mixing of ammonia fuel and diesel.

[0082] In some optional embodiments, taking the first fuel injection hole 21 as an example, the two first side fuel injection holes 212 are respectively located on both sides of the first middle fuel injection hole 211, and the angle of the sprayed diesel mist beam, or the third angle between the axis of the first side fuel injection hole 212 and the axis of the first middle fuel injection hole 211 is between 20° and 40°, and preferably 30°.

[0083] Furthermore, taking the second fuel injection hole 22 as an example, the two second side fuel injection holes 222 are respectively located on both sides of the second middle fuel injection hole 221, and the angle of the sprayed diesel mist beam, or the fourth angle between the axis of the second side fuel injection hole 222 and the axis of the second middle fuel injection hole 221 is between 35° and 55°, preferably different from the third angle, for example 45°, to further improve the mixing uniformity of diesel and ammonia fuel.

[0084] In some preferred embodiments, at least two third oil injection holes 23 are arranged at intervals along the circumferential direction.

[0085] In this embodiment, because the third injection hole group 13 faces the low turbulent kinetic energy region and the ammonia fuel equivalent injected is relatively low, the number of third injection holes 23 is preferably the same as the number of third injection holes 131, and the apertures of the third injection holes 23 are approximately equal. Alternatively, more third injection holes 23 may be provided to improve ignition efficiency and ensure combustion stability.

[0086] Figure 5 4 is a cross-sectional schematic diagram of an ammonia injector for a compression-ignition ammonia-diesel dual-fuel engine provided by an exemplary embodiment of the present invention.

[0087] In an exemplary embodiment, Figure 5 As shown, the ammonia injector 1 is composed of a housing 15 and a core 16. The first nozzle group 11, the second nozzle group 12, and the third nozzle group 13 are all formed on the housing 15. A cavity is formed inside the housing 15 for accommodating the ammonia fuel. The cavity is connected to the combustion chamber through the first nozzle group 11, the second nozzle group 12, and the third nozzle group 13.

[0088] According to an embodiment of the present disclosure, the ammonia injector 1 further includes a fourth spray hole 14 . The fourth spray hole 14 is configured as an annular spray hole and is located at the bottom of the ammonia injector 1 .

[0089] Specifically, such as Figure 2 、 Figure 3 and Figure 5 As shown, an opening is formed at the bottom of the ammonia injector 1, and a core 16 is arranged in the cavity and extends out of the shell 15 through the opening. The core 16 is configured to reciprocate in the vertical direction, blocking the opening to prevent the ammonia fuel from being sprayed, or forming an annular gap between the core 16 and the opening to allow the ammonia fuel to be sprayed.

[0090] More specifically, the tail of the core 16 is cylindrical and located inside the cavity. The head of the core 16 is conical, and the opening at the bottom of the shell 15 is flared with a gradually increasing inner diameter to match the conical head of the core 16, so that the sprayed ammonia fuel mist is trumpet-shaped, thereby increasing the flame diffusion speed. Figure 2 and Figure 3 The circular dotted line on the periphery of the ammonia injector 1 represents the trumpet-shaped ammonia fuel spray in a top view.

[0091] It will be understood by those skilled in the art that the features described in the various embodiments of the present invention may be combined and / or coupled in various ways, even if such combinations or couplings are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention may be combined and / or coupled in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or couplings fall within the scope of the present invention.

[0092] The above describes embodiments of the present invention. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A compression ignition ammonia-diesel dual-fuel engine comprising a cylinder block, a cylinder head, and a piston, wherein a combustion chamber is defined between the cylinder block and the cylinder head, and the piston is configured to reciprocate along the axial direction of the cylinder block, characterized in that: Also includes: an ammonia injector, mounted on the cylinder head and used to inject ammonia fuel, the ammonia injector being formed with a first nozzle group, a second nozzle group, and a third nozzle group arranged in an axial direction, the first nozzle group facing a high turbulent kinetic energy region at the upper portion of the combustion chamber, the second nozzle group facing a medium turbulent kinetic energy region at the middle portion of the combustion chamber, and the third nozzle group facing a low turbulent kinetic energy region at the lower portion of the combustion chamber; A diesel nozzle is installed on the cylinder head and is used for injecting diesel. The piston is suitable for compression igniting the diesel to ignite the ammonia fuel.

2. The compression ignition ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The ammonia fuel flow rate of the first injection hole group is greater than the ammonia fuel flow rate of the second injection hole group, and the ammonia fuel flow rate of the second injection hole group is greater than the ammonia fuel flow rate of the third injection hole group.

3. The compression ignition ammonia-diesel dual-fuel engine according to claim 2, characterized in that: The first nozzle group includes: a first intermediate spray hole; The two first spray holes are respectively located on both sides of the first middle spray hole along the circumferential direction, and the apertures of the first spray holes are smaller than the aperture of the first middle spray hole.

4. The compression ignition ammonia-diesel dual-fuel engine according to claim 3, characterized in that: The second nozzle group includes: second middle spray hole; The two second spray holes are respectively located on both sides of the second middle spray hole along the circumferential direction, and the apertures of the second spray holes are smaller than the aperture of the second middle spray hole.

5. The compression ignition ammonia-diesel dual-fuel engine according to claim 4, characterized in that: The third spray hole group includes at least two third spray holes.

6. The compression ignition ammonia-diesel dual-fuel engine according to any one of claims 1 to 5, characterized in that: The diesel nozzle and the ammonia injector are arranged at intervals in the circumferential direction, and the diesel nozzle is located on a side of the ammonia injector away from the ammonia fuel and injects diesel toward the ammonia fuel.

7. The compression ignition ammonia-diesel dual-fuel engine according to claim 6, characterized in that: The diesel nozzle is provided with a first fuel injection hole, a second fuel injection hole and a third fuel injection hole arranged in an axial direction. The oil beam sprayed from the first fuel injection hole is mixed with the ammonia fuel mist beam sprayed from the first nozzle group in a high turbulent kinetic energy area, the oil beam sprayed from the second fuel injection hole is mixed with the ammonia fuel mist beam sprayed from the second nozzle group in a medium turbulent kinetic energy area, and the oil beam sprayed from the third fuel injection hole is mixed with the ammonia fuel mist beam sprayed from the third nozzle group in a low turbulent kinetic energy area.

8. The compression ignition ammonia-diesel dual-fuel engine according to claim 7, characterized in that: The diesel flow rate of the first fuel injection hole is greater than the diesel flow rate of the second fuel injection hole, and the diesel flow rate of the second fuel injection hole is greater than the diesel flow rate of the third fuel injection hole.

9. The compression ignition ammonia-diesel dual-fuel engine according to claim 8, characterized in that: The first oil injection hole comprises: a first intermediate oil injection hole; The two first side oil spray holes are respectively located on both sides of the first middle oil spray hole along the circumferential direction, and the aperture of the first side oil spray hole is smaller than the aperture of the first middle oil spray hole.

10. The compression ignition ammonia-diesel dual-fuel engine according to claim 9, characterized in that: The second oil injection hole includes: second middle oil injection hole; two second side oil spray holes, respectively located on either side of the second middle oil spray hole along the circumferential direction, and the apertures of the second side oil spray holes are smaller than the aperture of the second middle oil spray hole; Preferably, at least two third oil injection holes are arranged at intervals along the circumferential direction.

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