Compression ignition ammonia-diesel dual fuel engine

Abstract

This invention provides a compression-ignition ammonia-diesel dual-fuel engine, relating to the field of engine technology. It includes a cylinder block, a cylinder head, and a piston. A combustion chamber is defined between the cylinder block and the cylinder head. The piston is configured to reciprocate along the axial direction of the cylinder block. It also includes an ammonia injector and a diesel nozzle. The ammonia injector is mounted on the cylinder head and is used to inject ammonia fuel. The ammonia injector has a first group of nozzles, a second group of nozzles, and a third group of nozzles arranged axially. The first group of nozzles faces the high turbulent kinetic energy region in the upper part of the combustion chamber, the second group of nozzles faces the medium turbulent kinetic energy region in the middle part of the combustion chamber, and the third group of nozzles faces the low turbulent kinetic energy region in the lower part of the combustion chamber. The diesel nozzle is mounted on the cylinder head and is used to inject diesel fuel. The piston is adapted to compress and ignite the diesel fuel to ignite the ammonia fuel.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically, to a compression-ignition ammonia-diesel dual-fuel engine. Background Technology

[0002] Ammonia (NH3), as a zero-carbon fuel, is a key candidate for future energy transition due to its high energy density (18.6 MJ / kg) and mature 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, which are difficult to electrify. However, the widespread application of ammonia fuel still faces several challenges: First, ammonia has a slow combustion rate (laminar flame speed is only 1 / 5 that of gasoline) and a high ignition temperature (651℃), resulting in low combustion efficiency; second, ammonia combustion easily generates nitrogen oxides (NOx), with emissions more than twice that of diesel engines, requiring after-treatment technologies; third, the toxicity and corrosiveness of ammonia to metal materials necessitate special protective designs in storage and transportation systems. Currently, researchers are improving the combustion characteristics of ammonia by blending it with hydrogen and optimizing the combustion chamber structure, but how to improve thermal efficiency while maintaining low emissions remains a core technical challenge.

[0003] Ammonia fuel engines are a new type of power unit, and their technical routes can be divided into spark ignition (SI), compression ignition (CI), and dual-fuel modes. Spark ignition engines face problems such as unstable flame propagation and large cycle fluctuations. Due to the high auto-ignition temperature of ammonia (>900℃), compression ignition engines also require a high compression ratio (>35:1) or the addition of highly reactive fuels (such as diesel) for ignition. The ammonia-diesel dual-fuel engine is a hybrid power system that combines the zero-carbon characteristics of ammonia with the high combustion reactivity of diesel, aiming to achieve low carbon emissions while ensuring stable engine operation. In this system, ammonia is the primary fuel (accounting for 50%~90% of energy), supplied through the intake manifold or injection system, while a small amount of diesel (10%~50%) is ignited through high-pressure in-cylinder injection. The high cetane number of diesel promotes the combustion of ammonia, thus overcoming the problems of difficult ignition and slow combustion speed of pure ammonia fuel.

[0004] Among the relevant direct injection engine technologies, there are few improvements in the injection method of ammonia fuel. 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. Moreover, they are closely related to the diffusion and distribution of ammonia fuel in the combustion chamber. Therefore, how to further optimize the injection system of ammonia-diesel dual-fuel engine and improve ignition stability and ammonia fuel substitution rate has become an urgent technical problem to be solved. Summary of the Invention

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

[0006] To achieve the above 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 further comprises: an ammonia injector mounted on the cylinder head for injecting ammonia fuel, wherein the ammonia injector has a first group of nozzles, a second group of nozzles, and a third group of nozzles arranged axially, the first group of nozzles facing the high turbulent kinetic energy region in the upper part of the combustion chamber, the second group of nozzles facing the medium turbulent kinetic energy region in the middle part of the combustion chamber, and the third group of nozzles facing the low turbulent kinetic energy region in the lower part of the combustion chamber; and a diesel nozzle mounted on the cylinder head for injecting diesel fuel. The piston is adapted to compress and ignite diesel fuel to ignite the ammonia fuel.

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

[0008] According to an embodiment of the present invention, the first nozzle group includes: a first intermediate nozzle; and two first nozzles located on both sides of the first intermediate nozzle in the circumferential direction, wherein the diameter of the first nozzles is smaller than the diameter of the first intermediate nozzle.

[0009] According to an embodiment of the present invention, the second nozzle group includes: a second intermediate nozzle; two second nozzles located on both sides of the second intermediate nozzle in the circumferential direction, and the diameter of the second nozzles is smaller than the diameter of the second intermediate nozzle.

[0010] According to an embodiment of the present invention, the above-mentioned third nozzle group includes at least two third nozzles.

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

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

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

[0014] According to an embodiment of the present invention, the first injection hole includes: a first intermediate injection hole; and two first side injection holes located on both sides of the first intermediate injection hole in the circumferential direction, wherein the diameter of the first side injection holes is smaller than the diameter of the first intermediate injection hole.

[0015] According to an embodiment of the present invention, the second injection hole includes: a second intermediate injection hole; and two second side injection holes located on both sides of the second intermediate injection hole in the circumferential direction, wherein the diameter of the second side injection holes is smaller than the diameter of the second intermediate injection hole.

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

[0017] The compression ignition ammonia-diesel dual-fuel engine provided by this invention simultaneously injects ammonia fuel and diesel fuel into the combustion chamber. This allows the diesel fuel to be ignited first by the piston, which then ignites the ammonia fuel, thus lowering the ignition temperature in the combustion chamber. Furthermore, by injecting ammonia fuel into different turbulent kinetic energy regions in the combustion chamber, the ammonia fuel is distributed more evenly in the combustion chamber, improving the diesel ignition efficiency and the stability of the combustion process, and reducing nitrogen oxide emissions. Attached Figure Description

[0018] Figure 1 This 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 This is a top view of a compression-ignition ammonia-diesel dual-fuel engine provided in an exemplary embodiment of the present invention;

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

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

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

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

[0024] 1. Ammonia injector;

[0025] 11. First nozzle group;

[0026] 111. First intermediate spray hole;

[0027] 112. First nozzle;

[0028] 12. Second nozzle group;

[0029] 121. Second intermediate spray hole;

[0030] 122. Second nozzle;

[0031] 13. Third nozzle group;

[0032] 131. Third nozzle;

[0033] 14. Fourth nozzle;

[0034] 15. Shell;

[0035] 16. Core;

[0036] 2. Diesel fuel injector;

[0037] 21. First fuel injection hole;

[0038] 211. First intermediate fuel injection hole;

[0039] 212. First side oil injection hole;

[0040] 22. Second fuel injection hole;

[0041] 221. Second intermediate fuel injection hole;

[0042] 222. Second side fuel injection hole;

[0043] 23. Third fuel injection hole;

[0044] 3. Cylinder block;

[0045] 4. Cylinder head;

[0046] 5. Piston. Detailed Implementation

[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 invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0048] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated 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 are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

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

[0051] Figure 1 This is a cross-sectional schematic diagram of a compression-ignition ammonia-diesel dual-fuel engine provided in an exemplary embodiment of the present invention. Figure 2 This is a top view of a compression-ignition ammonia-diesel dual-fuel engine provided in 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 system includes 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. 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. The ammonia injector 1 has a first group of nozzles 11, a second group of nozzles 12, and a third group of nozzles 13 arranged axially. The first group of nozzles faces the high turbulent kinetic energy region in the upper part of the combustion chamber, the second group of nozzles 12 faces the medium turbulent kinetic energy region in the middle of the combustion chamber, and the third group of nozzles 13 faces the low turbulent kinetic energy region in the lower part 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 adapted to compress and ignite diesel fuel to ignite the ammonia fuel.

[0053] In the combustion chamber, the upper space has a higher turbulent kinetic energy (TKE) due to its proximity to the ammonia injector 1, diesel nozzle 2, air intake, and compression ignition point, thus forming 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), and the energy is gradually dissipated, resulting in a decrease in turbulent kinetic energy, thus forming a medium turbulent kinetic energy region. Due to the shearing effect of the cylinder block 3 wall, the development of turbulence is further suppressed, and small-scale vortices further lose energy due to viscous dissipation, thus forming a low turbulent kinetic energy region.

[0054] Because ammonia fuel has a high auto-ignition temperature, requiring above 900°C, a compression ratio of 35 or higher is needed to ensure successful compression ignition. In this implementation, ammonia and diesel fuel are simultaneously injected into the combustion chamber. The diesel fuel is first compressed and ignited, followed by the ammonia fuel, thus lowering the ignition temperature of the mixed fuel (ammonia and diesel). Furthermore, by injecting ammonia fuel separately into different turbulent kinetic energy regions within the combustion chamber, the ammonia fuel is distributed more evenly, improving diesel ignition efficiency and combustion stability, and reducing nitrogen oxide emissions.

[0055] More specifically, during the compression stroke, piston 5 moves upward from the bottom dead center. When it reaches near the top dead center, ammonia injector 1 and diesel injector 2 begin to inject fuel. The diesel injector 2 may inject ammonia fuel slightly earlier than the ammonia injector 1, or it may inject fuel simultaneously with the ammonia injector 1. At this time, piston 5 continues to move upward, and the diesel fuel is first ignited by compression, which then ignites the ammonia fuel, pushing piston 5 downward to enter the power stroke.

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

[0057] In this implementation, the amount of ammonia fuel to be injected in the target area is adjusted according to the different turbulent kinetic energies 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, its ammonia fuel flow rate is achieved by adjusting the number of holes it contains or the diameter of the holes.

[0059] Figure 3 This is a top view of the ammonia injector of a compression-ignition ammonia-diesel dual-fuel engine provided in an exemplary embodiment of the present invention.

[0060] In one exemplary embodiment, such as Figure 3 As shown, the first nozzle group 11 includes a first intermediate nozzle 111 and two first nozzles 112. The two first nozzles 112 are located on both sides of the first intermediate nozzle 111 along the circumferential direction, and the diameter of the first nozzles 112 is smaller than the diameter of the first intermediate nozzle 111.

[0061] In this implementation, the large-diameter first intermediate nozzle 111 sprays a large flow rate of ammonia fuel with high injection energy to match the high-temperature and high-turbulence kinetic energy zone and form a fuel-rich environment, while the first nozzles 112 on both sides adopt a small diameter to avoid excessive ammonia fuel accumulation and unburned ammonia escape.

[0062] According to embodiments of this disclosure, such as Figure 3 As shown, the second nozzle group 12 includes a second intermediate nozzle 121 and two second nozzles 122. The two second nozzles 122 are located on both sides of the second intermediate nozzle 121 along the circumferential direction, and the diameter of the second nozzles 122 is smaller than the diameter of the second intermediate nozzle 121.

[0063] In this implementation, similar to the first nozzle group 11, the large-diameter second intermediate nozzle 121 sprays a large flow rate of ammonia fuel with high injection energy to match the high-temperature, high-turbulence kinetic energy zone and create a fuel-rich environment. It should be noted that the high-turbulence kinetic energy zone targeted by the second intermediate nozzle 121 is actually the portion with relatively high turbulence kinetic energy within the overall intermediate turbulence kinetic energy region of the combustion chamber, not the high-turbulence kinetic energy region described in the above embodiment. The second nozzles 122 on both sides use small diameters to avoid excessive ammonia fuel accumulation leading to unburned ammonia escape.

[0064] In some optional embodiments, taking the first nozzle group 11 as an example, the two first nozzles 112 are located on both sides of the first intermediate nozzle 111, and the included angle of the sprayed ammonia fuel mist, or the first included angle between the axis of the first nozzle 112 and the axis of the first intermediate 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 located on both sides of the second intermediate nozzle 121, and the included angle of the sprayed ammonia fuel mist, or the second included angle between the axis of the second nozzle 122 and the axis of the second intermediate nozzle 121, is between 35° and 55°, preferably different from the first included angle, for example 45°, so as to further improve the uniformity of ammonia fuel distribution.

[0066] According to embodiments of this disclosure, such as Figure 3 As shown, the third nozzle group 13 includes at least two third nozzles 131.

[0067] In this implementation, since the third nozzle group 13 is oriented towards the low turbulent kinetic energy region, the ammonia fuel equivalence ratio in this region is appropriately reduced to prevent ammonia escape and avoid the accidental generation of thermal nitrogen oxides due to excessively high temperature in the low turbulent kinetic energy region.

[0068] In some alternative embodiments, the number of third nozzles 131 is preferably two, or the number of third nozzles 131 is increased while the diameter of the third nozzles 131 is reduced to maintain the equivalence ratio.

[0069] In one exemplary embodiment, such as Figure 2 As shown, the diesel nozzle 2 and the ammonia injector 1 are arranged at intervals along the circumferential direction, and the diesel nozzle 2 is located on the side of the ammonia injector 1 away from the ammonia fuel, and sprays diesel towards the ammonia fuel.

[0070] In this embodiment, the orientation of the first nozzle group 11, the second nozzle group 12 and the third nozzle group 13 of the ammonia injector 1 is roughly in line with the vortex direction inside the cylinder 3, that is, the circumferential direction of the cylinder 3. With the direction of 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 ammonia fuel.

[0071] In some other embodiments, there are two ammonia injectors 1 and two diesel nozzles 2. Taking the ammonia injector 1 as an example, the two ammonia injectors 1 are arranged symmetrically about the center of the cylinder block 3. In this way, the two ammonia injectors 1 work together to inject ammonia fuel, which better follows the vortex direction.

[0072] According to embodiments of this disclosure, such as Figure 1 and Figure 2 As shown, the diesel nozzle 2 has a first injection hole 21, a second injection hole 22, and a third injection hole 23 arranged in the axial direction. The oil jet ejected from the first injection hole 21 mixes with the ammonia fuel mist jet ejected from the first injection hole group 11 in the high turbulent kinetic energy region. The oil jet ejected from the second injection hole 22 mixes with the ammonia fuel mist jet ejected from the second injection hole group 12 in the medium turbulent kinetic energy region. The oil jet ejected from the third injection hole 23 mixes with the ammonia fuel mist jet ejected from the third injection hole group 13 in the low turbulent kinetic energy region.

[0073] In this embodiment, the first nozzle group 11 of the ammonia injector 1 is on the same horizontal plane as the first nozzle 21 of the diesel nozzle 2, the second nozzle group 12 is on the same horizontal plane as the second nozzle 22, and the third nozzle group 13 is on the same horizontal plane as the third nozzle 23. By injecting diesel fuel using an injection method similar to that of ammonia fuel, the mixing of diesel fuel and ammonia fuel is further promoted, the mixing uniformity is improved, and the ammonia fuel is better ignited.

[0074] According to further embodiments of this 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 this implementation, since the first injection hole 21, the second injection hole 22 and the third injection hole 23 are also oriented toward the high turbulent kinetic energy region, the medium turbulent kinetic energy region and the low turbulent kinetic energy region in the cylinder block 3, respectively, based on a similar principle, the diesel fuel injection quantity is correspondingly higher for the region with higher turbulent kinetic energy, so as to more effectively ignite the ammonia fuel.

[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 or the diameter of the holes.

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

[0078] In one exemplary embodiment, such as Figure 4 As shown, the first fuel injection hole 21 includes a first intermediate fuel injection hole 211 and two first side fuel injection holes 212. The two first side fuel injection holes 212 are located on both sides of the first intermediate fuel injection hole 211 in the circumferential direction, and the diameter of the first side fuel injection holes 212 is smaller than the diameter of the first intermediate fuel injection hole 211.

[0079] In this embodiment, the large-diameter first intermediate injection hole 211 injects a large flow rate of diesel fuel with high injection energy to match the high equivalence ratio ammonia fuel injected by the first intermediate injection hole 111. The diameters of the first side injection holes 212 on both sides are smaller, and the diesel flow rate is relatively lower, but thanks to their arrangement, they can cover a wider range, enhance mixing efficiency, and make the ammonia fuel and diesel fuel mix more evenly.

[0080] According to embodiments of this disclosure, such as Figure 4 As shown, the second fuel injection hole 22 includes a second intermediate fuel injection hole 221 and two second side fuel injection holes 222. The two second side fuel injection holes 222 are located on both sides of the second intermediate fuel injection hole 221 in the circumferential direction, and the diameter of the second side fuel injection holes 222 is smaller than the diameter of the second intermediate fuel injection hole 221.

[0081] In this embodiment, similar to the first injection hole 21, the large-diameter second intermediate injection hole 221 injects a large flow rate of diesel fuel with high injection energy to match the high equivalence ratio ammonia fuel injected by the second intermediate injection hole 121. The second side injection holes 222 on both sides have smaller diameters and relatively lower diesel flow rates, but thanks to their arrangement, they can cover a wider range, enhance mixing efficiency, and make the ammonia fuel and diesel fuel mix more evenly.

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

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

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

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

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

[0087] In one exemplary embodiment, such as Figure 5 As shown, the ammonia injector 1 consists 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 for containing ammonia fuel is formed inside the housing 15, and 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 nozzle 14, which is configured as an annular nozzle and located at the bottom of the ammonia injector 1.

[0089] Specifically, such as Figure 2 , Figure 3 and Figure 5 As shown, the bottom of the ammonia injector 1 has an opening, and the core 16 is disposed in the cavity and extends out of the housing 15 through the opening. The core 16 is configured to reciprocate in the vertical direction, either blocking the opening to prevent ammonia fuel from being injected, or forming an annular gap with the opening to allow ammonia fuel to be injected.

[0090] More specifically, the tail of the core 16 is constructed in a cylindrical shape and located inside the cavity. The head of the core 16 is constructed in a conical shape, and the opening at the bottom of the shell 15 is constructed as a flared structure with a gradually increasing inner diameter to cooperate with the conical head of the core 16, so that the ejected ammonia fuel mist is funnel-shaped, thereby increasing the flame diffusion speed. Figure 2 and Figure 3 The circular dashed line around the outer periphery of the ammonia injector 1 represents the trumpet-shaped ammonia fuel spray from a top-down perspective.

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

[0092] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A compression ignition ammonia-diesel dual fuel engine comprising a cylinder block, a cylinder head and a piston, the cylinder block and the cylinder head defining a combustion chamber therebetween, the piston being configured to reciprocate in an axial direction of the cylinder block, characterized in that, Also includes: An ammonia injector is installed on the cylinder head and used to inject ammonia fuel. The ammonia injector has a first group of nozzles, a second group of nozzles, and a third group of nozzles arranged in an axial direction. The first group of nozzles faces the high turbulent kinetic energy region in the upper part of the combustion chamber, the second group of nozzles faces the medium turbulent kinetic energy region in the middle part of the combustion chamber, and the third group of nozzles faces the low turbulent kinetic energy region in the lower part of the combustion chamber. A diesel injector is mounted on the cylinder head and used to inject diesel fuel; the piston is adapted to compress and ignite diesel fuel to ignite ammonia fuel. The ammonia fuel flow rate of the first nozzle group is greater than that of the second nozzle group, and the ammonia fuel flow rate of the second nozzle group is greater than that of the third nozzle group. The first nozzle group includes: First intermediate nozzle; Two first nozzles are located on both sides of the first intermediate nozzle along the circumferential direction, and the diameter of the first nozzle is smaller than that of the first intermediate nozzle. The second nozzle assembly includes: Second intermediate nozzle; Two second nozzles are located on either side of the second intermediate nozzle along the circumferential direction, and the diameter of the second nozzle is smaller than that of the second intermediate nozzle.

2. The compression-ignition ammonia-diesel dual-fuel engine according to claim 1, characterized in that, The third nozzle group includes at least two third nozzles.

3. The compression-ignition ammonia-diesel dual-fuel engine according to claim 1 or 2, 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 the side of the ammonia injector away from the ammonia fuel, and sprays diesel towards the ammonia fuel.

4. The compression-ignition ammonia-diesel dual-fuel engine according to claim 3, characterized in that, The diesel nozzle has a first injection hole, a second injection hole, and a third injection hole arranged in the axial direction. The oil jet ejected from the first injection hole mixes with the ammonia fuel mist ejected from the first injection hole group in the high turbulent kinetic energy region. The oil jet ejected from the second injection hole mixes with the ammonia fuel mist ejected from the second injection hole group in the medium turbulent kinetic energy region. The oil jet ejected from the third injection hole mixes with the ammonia fuel mist ejected from the third injection hole group in the low turbulent kinetic energy region.

5. The compression-ignition ammonia-diesel dual-fuel engine according to claim 4, characterized in that, The diesel flow rate of the first injection hole is greater than that of the second injection hole, and the diesel flow rate of the second injection hole is greater than that of the third injection hole.

6. The compression-ignition ammonia-diesel dual-fuel engine according to claim 5, characterized in that, The first injection hole includes: First intermediate fuel injection hole; Two first side injection holes are located on both sides of the first middle injection hole in the circumferential direction, and the diameter of the first side injection holes is smaller than the diameter of the first middle injection hole.

7. The compression-ignition ammonia-diesel dual-fuel engine according to claim 6, characterized in that, The second injection hole includes: Second intermediate oil injection hole; Two second side injection holes are located on both sides of the second middle injection hole in the circumferential direction, and the diameter of the second side injection holes is smaller than that of the second middle injection hole.

8. The compression-ignition ammonia-diesel dual-fuel engine according to claim 7, characterized in that, At least two third injection holes are provided at intervals along the circumferential direction.

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