Liquid ammonia direct injection engine with passive pre-chamber and its partition control method

Abstract

This application relates to a liquid ammonia direct injection engine with a passive pre-combustion chamber and its zone control method. The liquid ammonia direct injection engine includes: a cylinder mechanism and an ammonia injection mechanism; an ignition mechanism including a housing, an injection section, and a spark plug; the housing is connected to the cylinder block and has a passive pre-combustion chamber communicating with the main combustion chamber; the spark plug is located at the end of the passive pre-combustion chamber away from the cylinder block, and the end of the housing near the cylinder block has an injection section with jet nozzles communicating with the passive pre-combustion chamber and the main combustion chamber respectively. The liquid ammonia direct injection engine of this application can effectively improve the charging efficiency by injecting liquid ammonia; simultaneously, by setting up a passive pre-combustion chamber, it can effectively improve the ignition efficiency and alleviate the problem of liquid ammonia fuel being difficult to ignite; combined with the zone control method of the liquid ammonia direct injection engine proposed in this application, it further improves the stability of the ignition and combustion process, enabling the engine to stably ignite and burn rapidly under all operating conditions.

Description

Technical Field

[0001] This application relates to the field of engine technology, and in particular to a liquid ammonia direct injection engine with a passive pre-combustion chamber and a method for zoned control thereof. Background Technology

[0002] Breakthroughs in key zero-carbon power technologies, currently lacking significant advancements, have become an essential requirement for engine research in the context of the dual-carbon era. Among all zero-carbon fuels, hydrogen, ammonia, and hydrazine are the most promising. However, hydrazine, due to its high toxicity and instability, is unsuitable for widespread use. Ammonia fuel boasts numerous advantages, including low cost, safety, ease of storage and transportation, and high energy density. Its stoichiometric calorific value is comparable to fossil fuels, achieving power densities similar to lean-burn diesel. However, ammonia exhibits low reactivity, a high auto-ignition temperature, and a narrow ignition concentration range. Hydrogen, as a typical representative of zero-carbon and reactive fuels, possesses advantages such as low ignition energy, a wide air-fuel ratio range, and rapid flame propagation. Co-firing hydrogen with ammonia can enhance combustion speed and thus improve engine efficiency. However, ammonia's low reactivity makes igniting the air-fuel mixture more challenging when using ammonia as fuel in an engine. Summary of the Invention

[0003] Therefore, it is necessary to provide a liquid ammonia direct injection engine with a passive pre-combustion chamber and its zone control method that has high ignition efficiency and stability, addressing the problem of unstable combustion in liquid ammonia direct injection engines.

[0004] On one hand, this application provides a liquid ammonia direct injection engine with a passive pre-combustion chamber, comprising:

[0005] A cylinder mechanism includes a cylinder body and a piston, the piston being movably mounted within the cylinder body along the axial direction of the cylinder body, and having a main combustion chamber between the piston and the cylinder body; and

[0006] An ammonia injection mechanism, connected to the cylinder block, is configured to inject liquid ammonia into the main combustion chamber;

[0007] An ignition mechanism, comprising a housing and a spark plug; the housing is connected to the cylinder block and has a passive pre-combustion chamber communicating with the main combustion chamber; the spark plug is located at the end of the passive pre-combustion chamber away from the cylinder block, and the end of the housing near the cylinder block is provided with an injection section, the injection section having jet nozzles communicating with the passive pre-combustion chamber and the main combustion chamber respectively.

[0008] In one embodiment, both the injection section and the jet nozzle are located within the main combustion chamber.

[0009] In one embodiment, the jet nozzles are provided in multiple ways, and each jet nozzle faces a different direction.

[0010] In one embodiment, the housing mounting portion has a mounting hole corresponding to the cylinder body, and the mounting portion is connected to the mounting hole.

[0011] In one embodiment, the cylinder block includes a cylinder liner and a cylinder head connected to the cylinder liner, the cylinder head having the mounting hole.

[0012] In one embodiment, an intake and exhaust mechanism is further included, the intake and exhaust mechanism being configured to deliver fuel into the main combustion chamber; the intake and exhaust mechanism includes an intake passage and an exhaust passage respectively connected to the main combustion chamber, the intake passage being connected to a fuel injector for injecting fuel.

[0013] In one embodiment, the ratio of the volume of the passive pre-combustion chamber to the maximum volume of the main combustion chamber is less than 0.1.

[0014] In one embodiment, the angle between the central axis of the jet nozzle and the central axis of the cylinder is α, where 20°≤α≤50°.

[0015] In one embodiment, the diameter of the jet nozzle is d, where 0.1 mm ≤ d ≤ 1 mm.

[0016] On one hand, this application provides a zone control method for a liquid ammonia direct injection engine, applied to the aforementioned liquid ammonia direct injection engine with a passive pre-combustion chamber, the control method comprising:

[0017] When the liquid ammonia direct injection engine is running, the intake air temperature of the main combustion chamber is adjusted to be greater than 100°C; the operating conditions of the liquid ammonia direct injection engine include a first operating condition zone, a second operating condition zone, and a third operating condition zone.

[0018] In the first operating condition zone, the load of the liquid ammonia direct injection engine is less than or equal to 40%; in the first operating condition zone, the injection pressure of the ammonia injection mechanism, the liquid ammonia injection duration of the ammonia injection mechanism, the fuel injection pressure of the intake and exhaust mechanism, and / or the fuel injection duration of the intake and exhaust mechanism are adjusted so that the fuel substitution rate is in the range of 20-50%;

[0019] In the second operating condition zone, the load of the liquid ammonia direct injection engine is greater than 40% and less than or equal to 65%; in the second operating condition zone, the injection pressure of the ammonia injection mechanism, the liquid ammonia injection duration of the ammonia injection mechanism, the fuel injection pressure of the intake and exhaust mechanism, and / or the fuel injection duration of the intake and exhaust mechanism are adjusted so that the fuel substitution rate is in the range of 10-40%;

[0020] In the third operating condition zone, the load of the liquid ammonia direct injection engine is greater than 65%; in the third operating condition zone, the injection pressure of the ammonia injection mechanism, the liquid ammonia injection duration of the ammonia injection mechanism, the fuel injection pressure of the intake and exhaust mechanism, and / or the fuel injection duration of the intake and exhaust mechanism are adjusted so that the fuel substitution rate is in the range of 20-50%.

[0021] The liquid ammonia direct injection engine of this application can effectively improve the charging efficiency by injecting liquid ammonia; at the same time, by setting a passive pre-combustion chamber, the ignition efficiency can be effectively improved, and the problem of ammonia fuel being difficult to ignite due to the heat carried away by liquid ammonia vaporization can be improved; combined with the zone control method of the liquid ammonia direct injection engine proposed in this application, the stability of the ignition and combustion process is further improved, so that the engine can stably ignite and burn rapidly under all operating conditions. Attached Figure Description

[0022] Figure 1 This is a partial structural schematic diagram of a liquid ammonia direct injection engine with a passive pre-combustion chamber according to an embodiment of this application.

[0023] Figure 2 This is a schematic diagram of the structure of a liquid ammonia direct injection engine with a passive pre-combustion chamber according to an embodiment of this application.

[0024] Figure 3 This is a schematic diagram of the partitioning of a control method for a liquid ammonia direct injection engine with a passive pre-combustion chamber according to an embodiment of this application. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0027] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0031] Ammonia is a zero-carbon fuel with numerous advantages, including low cost, safety, ease of storage and transportation, and high energy density. Therefore, using ammonia as fuel in engines can significantly reduce carbon emissions. However, ammonia has low reactivity, making it difficult to ignite the air-fuel mixture when using it in an engine. In view of this, this application proposes a liquid ammonia direct injection engine and its control method, as well as a vehicle, aiming to solve the problem of the difficulty in igniting the air-fuel mixture in engines.

[0032] See Figure 1 and Figure 2 , Figure 1 and Figure 2 A schematic diagram of the structure of a liquid ammonia direct injection engine with a passive pre-combustion chamber is shown in one embodiment of this application. The liquid ammonia direct injection engine 1 provided in one embodiment of this application is suitable for vehicles. The liquid ammonia direct injection engine 1 includes a cylinder mechanism 10, an ammonia injection mechanism 20, an intake and exhaust mechanism 40, and an ignition mechanism 30.

[0033] The cylinder mechanism 10 includes a cylinder body 11 and a piston 12. The piston 12 is movably installed inside the cylinder body 11 along the axial direction of the cylinder body 11, and a main combustion chamber 13 is provided between the piston 12 and the cylinder body 11.

[0034] The ammonia injection mechanism 20 is connected to the cylinder block 11 and is configured to inject fuel into the main combustion chamber 13. In this embodiment, the fuel includes liquid ammonia. Since ammonia has a low calorific value and requires a large filling volume, a direct in-cylinder injection of liquid ammonia is used to effectively improve filling efficiency.

[0035] The intake and exhaust mechanism 40 is connected to the cylinder block 11 and is configured to deliver a portion of the fuel and air into the main combustion chamber 13. In this embodiment, the fuel for the liquid ammonia direct injection engine 1 is an ammonia-hydrogen mixture, and the intake and exhaust mechanism 40 is used to input the hydrogen-air mixture, which is then injected into the main combustion chamber 13 via the ignition mechanism 30.

[0036] An ignition mechanism 30 is connected to the cylinder block 11. The ignition mechanism 30 includes a housing, an injection section 32, and a spark plug 33. The housing is connected to the cylinder block 11 and has a passive pre-combustion chamber communicating with the main combustion chamber 13. The spark plug 33 is located at the end of the passive pre-combustion chamber 31 away from the cylinder block 11. The injection section 32 is located at the end of the housing close to the cylinder block 11, and the housing and the injection section 32 are integrally formed. The injection section 32 has jet nozzles 34 communicating with both the passive pre-combustion chamber 31 and the main combustion chamber 13. The spark plug 33 is configured to ignite fuel entering the passive pre-combustion chamber 31, so that the burned fuel is ejected through the jet nozzles 34.

[0037] Considering the difficulty of ammonia fuel combustion, a pre-combustion chamber is needed to ensure stable ignition and rapid combustion, in addition to mixing with hydrogen. The hydrogen-air mixture enters the cylinder during the intake phase, and liquid ammonia is injected immediately after the intake valve closes to promote mixing. During the compression stroke, the ammonia-hydrogen-air mixture is forced into the pre-combustion chamber by the rising piston through high-speed jet orifices. Near top dead center, the ammonia-hydrogen-air mixture in the pre-combustion chamber is ignited by the spark plug, causing a rapid increase in pressure. A large number of reactive groups are ejected through jet orifices on the passive pre-combustion chamber, forming jet flames. These flames ignite at multiple points evenly distributed circumferentially within the main combustion chamber 13, causing the mixture to burn rapidly from the edge to the center, resulting in a rapid increase in cylinder combustion pressure.

[0038] The ratio of the volume of the passive pre-combustion chamber 31 to the maximum volume of the main combustion chamber 13 is less than 0.1. Preferably, the ratio of the volume of the passive pre-combustion chamber 31 to the maximum volume of the main combustion chamber 13 is less than or equal to 0.04 and greater than or equal to 0.02. In this embodiment, the ratio of the volume of the passive pre-combustion chamber 31 to the maximum volume of the main combustion chamber 13 is 0.025.

[0039] For liquid ammonia engines, liquid ammonia is highly susceptible to vaporization, absorbing a large amount of heat during the vaporization process. By setting up a passive pre-combustion chamber 31, higher ignition energy can be provided. The ignition mechanism 30 is connected to the main combustion chamber 13 through the passive pre-combustion chamber 31. During the compression stroke, fuel enters and fills the passive pre-combustion chamber 31. According to the set ignition timing, it is ignited by the spark plug 33 in the passive pre-combustion chamber 31. When the fuel is burning in the passive pre-combustion chamber 31, it is injected from the jet nozzle 34 into the main combustion chamber 13 to complete stable ignition.

[0040] At least a portion of the ignition mechanism 30 extends into the cylinder block 11, and this extended portion is provided with jet nozzles 34. Specifically, both the injection section 32 and the jet nozzles 34 are located within the main combustion chamber 13. The flame injected by the ignition mechanism 30 can penetrate into the interior of the gas-fuel mixture, thereby making full contact with the mixture and better igniting it. Specifically, the ignition mechanism 30 also includes an injection section 32, which is located at the end of the housing facing the cylinder block 11. The injection section 32 is disposed within the main combustion chamber 13, and the injection section 32 is provided with jet nozzles 34.

[0041] The cylinder block 11 includes a cylinder liner and a cylinder head (not shown in the figure), and the cylinder head is provided with mounting holes. The housing has a mounting part that connects to the mounting holes, thereby mounting the housing onto the cylinder head. Multiple mounting holes may be provided to allow the ammonia injection mechanism 20, intake and exhaust mechanisms 40, etc., to be mounted on the cylinder head.

[0042] Multiple jet nozzles 34 are provided, each facing a different direction. These multiple jet nozzles 34 are equidistantly arranged on the injection section 32. The high-temperature flame, after ignition, expands and is injected into the main combustion chamber 13 through these multiple jet nozzles 34. This allows the high-temperature flame to contact the gas mixture at different locations within the main combustion chamber 13, creating multiple ignition sources and rapidly inducing strong turbulence within the main combustion chamber 13, igniting the gas mixture and achieving stable and efficient ignition.

[0043] The angle between the central axis of each jet nozzle 34 and the central axis of the cylinder 11 is α, where 20°≤α≤50°, preferably 30°≤α≤50°. In this embodiment, the angle α between the central axis of each jet nozzle 34 and the central axis of the cylinder 11 is 30°. The extension direction of the jet nozzle 34 determines the direction of flame injection. When the central axis of the jet nozzle 34 forms an angle with the central axis of the cylinder 11, the flame will be injected towards the outer layer of the main combustion chamber 13 relative to the central axis. This will cause the flame to only contact the mixed gas located at the outer edge of the main combustion chamber 13 and ignite the mixed gas at the outer edge first, allowing the flame to contact more of the mixed gas, resulting in better ignition and more complete combustion of the mixed gas. At the same time, it will create stronger combustion turbulence, making the ammonia gas burn more completely.

[0044] The diameter of the jet nozzle 34 is d, which is 0.1 mm ≤ d ≤ 1 mm, preferably 0.1 mm ≤ d ≤ 0.5 mm. In this embodiment, the diameter d of the jet nozzle 34 is 0.5 mm. The smaller diameter of the jet nozzle 34 in this application can provide a higher flame jet velocity and flame penetration distance. The flame velocity increases when passing through the small-diameter jet nozzle 34, which results in a longer flame penetration distance, thereby ensuring sufficient contact between the flame and the gas mixture.

[0045] The intake and exhaust mechanism 40 includes an intake duct 41 and an exhaust duct 42 respectively connected to the main combustion chamber 13. A fuel injector 45 for injecting fuel is connected to the intake duct 41. In related technologies, engines generally use active pre-combustion chambers, but active pre-combustion chambers have complex arrangements, occupy a large amount of space, and require a large cylinder head space. The passive pre-combustion chamber 31 of this application is a passive pre-combustion chamber. Hydrogen is not directly injected into the passive pre-combustion chamber 31, but enters the main combustion chamber 13 through the intake duct 41 to mix with the ammonia-air mixture, and enters the passive pre-combustion chamber 31 during the compression stroke of the cylinder mechanism 10. The passive pre-combustion chamber 31 has a simple arrangement, compact structure, and small cylinder head space requirement. While providing the same combustion energy, its volume size is much smaller than that of the active pre-combustion chamber. Specifically, in this embodiment, the fuel injector 45 provides hydrogen as fuel to the intake duct 41, and the hydrogen enters the main combustion chamber 13 through the intake duct 41. An intake valve 43 is provided at the connection between the intake manifold 41 and the main combustion chamber 13 of the cylinder block 11, and an exhaust valve 44 is provided at the connection between the exhaust manifold 42 and the main combustion chamber 13 of the cylinder block 11. Furthermore, the intake valve 43 or the exhaust valve 44 is located between the ammonia injection mechanism 20 and the ignition mechanism 30.

[0046] The ammonia injection mechanism 20 is connected to one side of the cylinder block 11, while the ignition mechanism 30 is connected to the center of the cylinder block 11. The ammonia injection port of the ammonia injection mechanism 20 is directly connected to the cylinder block 11, thus connecting the ammonia injection mechanism 20 to the main combustion chamber 13. The extension direction of the ammonia injection mechanism 20 (i.e., the orientation of the jet nozzle 34) is adjusted according to combustion requirements, external space of the cylinder block 11, and other factors.

[0047] The piston 12 of the cylinder mechanism 10 has a concave top surface facing the main combustion chamber 13. The cylinder head is a flat-bottomed cylinder head. Specifically, in this embodiment, the top surface of the piston 12 is a concave shape that is recessed away from the main combustion chamber 13. The concave top surface can couple the airflow direction of the fuel intake with the liquid ammonia injection direction of the ammonia injection mechanism 20, effectively promoting the formation of tumble flow in the cylinder to enhance the ammonia-air mixing effect.

[0048] The liquid ammonia direct injection engine 1 also includes a heating mechanism 50, which is located on the intake port 41 of the intake and exhaust mechanism 40. The heating mechanism 50 is used to increase the intake air temperature to compensate for the decrease in cylinder temperature caused by the heat absorption of liquid ammonia vaporization.

[0049] In some embodiments, multiple cylinder mechanisms 10 are provided, and the intake and exhaust mechanisms 40 may include multiple intake manifolds, with each intake manifold corresponding to and connected to one of the multiple cylinder mechanisms 10. In some embodiments, multiple ammonia injection mechanisms 20 are provided, with each ammonia injection mechanism 20 corresponding to and connected to one of the main combustion chambers 13 of the multiple cylinder mechanisms 10. The one-to-one connection between the multiple ammonia injection mechanisms 20 and the multiple cylinder mechanisms 10 allows each cylinder mechanism 10 to directly receive the injection of liquid ammonia, while the multiple intake manifolds supply air to each cylinder mechanism 10, thus completing the air intake for each cylinder mechanism 10.

[0050] In some embodiments, multiple ammonia injection mechanisms 20 are provided, and the multiple ammonia injection mechanisms 20 are connected to the cylinder head. Each ammonia injection mechanism 20 injects liquid ammonia into the cylinder mechanism 10.

[0051] In some embodiments, the ammonia injection mechanism 20 is connected to the intake and exhaust mechanism 40. The ammonia injection mechanism 20 injects liquid ammonia into the intake duct 41, thereby mixing the air or hydrogen gas in the intake duct 41 with the ammonia gas, which allows the intake duct 41 to directly input the mixed gas into the main combustion chamber 13.

[0052] Combination Figure 3 As shown, this application also proposes a zone control method for a liquid ammonia direct injection engine 1, applicable to the aforementioned liquid ammonia direct injection engine 1 with a passive pre-combustion chamber or vehicle. The control method includes:

[0053] When the liquid ammonia direct injection engine 1 is running, the adjustment is made so that the intake temperature of the gas injected into the main combustion chamber 13 is greater than 100°C.

[0054] The operating conditions of the liquid ammonia direct injection engine 1 include three operating conditions: the first operating condition zone, the second operating condition zone, and the third operating condition zone. Specifically:

[0055] In the first operating condition zone, the load of the liquid ammonia direct injection engine 1 is less than or equal to 40%; in the first operating condition zone, the injection pressure of the ammonia injection mechanism 20, the liquid ammonia injection duration of the ammonia injection mechanism 20, the fuel injection pressure of the intake and exhaust mechanism 40, and / or the fuel injection duration of the intake and exhaust mechanism 40 are adjusted so that the hydrogen fuel substitution rate is in the range of 20-50%;

[0056] In the second operating condition zone, the load of the liquid ammonia direct injection engine 1 is greater than 40% and less than or equal to 65%; in the second operating condition zone, the injection pressure of the ammonia injection mechanism 20, the liquid ammonia injection duration of the ammonia injection mechanism 20, the fuel injection pressure of the intake and exhaust mechanism 40, and / or the fuel injection duration of the intake and exhaust mechanism 40 are adjusted so that the hydrogen fuel substitution rate is in the range of 10-40%;

[0057] In the third operating condition zone, the load of the liquid ammonia direct injection engine 1 is greater than 65%; in the third operating condition zone, the injection pressure of the ammonia injection mechanism 20, the liquid ammonia injection duration of the ammonia injection mechanism 20, the fuel injection pressure of the intake and exhaust mechanism 40 and / or the fuel injection duration of the intake and exhaust mechanism 40 are adjusted so that the hydrogen fuel substitution rate is in the range of 20-50%.

[0058] Furthermore, the first operating condition zone corresponds to the liquid ammonia direct injection engine 1 operating under low load, the second operating condition zone corresponds to the liquid ammonia direct injection engine 1 operating under medium load, and the third operating condition zone corresponds to the liquid ammonia direct injection engine 1 operating under high load.

[0059] Furthermore, the steps for adjusting the injection pressure of the ammonia injection mechanism 20 and the fuel injection duration of the intake and exhaust mechanism 40 include:

[0060] In the first operating condition zone, the hydrogen injection pressure of the intake and exhaust mechanism 40 is greater than or equal to 3 bar and less than or equal to 7 bar. In this embodiment, the hydrogen injection pressure of the intake and exhaust mechanism 40 is 5 bar. The duration of hydrogen injection of the intake and exhaust mechanism 40 corresponds to a crankshaft angle of 10-30°CA for the liquid ammonia direct injection engine 1. The liquid ammonia injection pressure of the ammonia injection mechanism 20 is greater than or equal to 200 bar and less than or equal to 280 bar. In this embodiment, the liquid ammonia injection pressure of the ammonia injection mechanism 20 is 250 bar. The duration of liquid ammonia injection of the ammonia injection mechanism 20 corresponds to a crankshaft angle of 30-50°CA for the liquid ammonia direct injection engine 1.

[0061] In the second operating condition zone, the hydrogen injection pressure of the intake and exhaust mechanism 40 is greater than or equal to 5 bar and less than or equal to 10 bar. In this embodiment, the hydrogen injection pressure of the intake and exhaust mechanism 40 is 8 bar. The duration of hydrogen injection of the intake and exhaust mechanism 40 corresponds to a crankshaft angle of 20-40°CA for the liquid ammonia direct injection engine 1. The liquid ammonia injection pressure of the ammonia injection mechanism 20 is greater than or equal to 250 bar and less than or equal to 340 bar. In this embodiment, the liquid ammonia injection pressure of the ammonia injection mechanism 20 is 300 bar. The duration of liquid ammonia injection of the ammonia injection mechanism 20 corresponds to a crankshaft angle of 50-70°CA for the liquid ammonia direct injection engine 1.

[0062] In the third operating condition zone, the hydrogen injection pressure of the intake and exhaust mechanism 40 is greater than or equal to 8 bar and less than or equal to 12 bar. In this embodiment, the hydrogen injection pressure of the intake and exhaust mechanism 40 is 10 bar. The duration of hydrogen injection of the intake and exhaust mechanism 40 corresponds to a crankshaft angle of 30-50°CA for the liquid ammonia direct injection engine 1. The liquid ammonia injection pressure of the ammonia injection mechanism 20 is greater than or equal to 300 bar and less than or equal to 400 bar. In this embodiment, the liquid ammonia injection pressure of the ammonia injection mechanism 20 is 350 bar. The duration of liquid ammonia injection of the ammonia injection mechanism 20 corresponds to a crankshaft angle of 70-90°CA for the liquid ammonia direct injection engine 1.

[0063] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A zone control method for a liquid ammonia direct injection engine, characterized in that, A liquid ammonia direct injection engine with a passive pre-combustion chamber is provided, the liquid ammonia direct injection engine with a passive pre-combustion chamber comprising: A cylinder mechanism includes a cylinder body and a piston, the piston being movably mounted within the cylinder body along the axial direction of the cylinder body, and defining a main combustion chamber between the piston and the cylinder body; and An ammonia injection mechanism, connected to the cylinder block, is configured to inject liquid ammonia into the main combustion chamber; An ignition mechanism, comprising a housing and a spark plug; the housing is connected to the cylinder block and has a passive pre-combustion chamber communicating with the main combustion chamber; the spark plug is disposed at the end of the passive pre-combustion chamber away from the cylinder block, and the end of the housing near the cylinder block is provided with an injection section, the injection section having jet nozzles communicating with the passive pre-combustion chamber and the main combustion chamber respectively; An intake and exhaust mechanism, configured to deliver fuel into the main combustion chamber; Furthermore, the fuel is not directly injected into the passive pre-combustion chamber, but enters the main combustion chamber and enters the passive pre-combustion chamber during the compression stroke of the cylinder mechanism; The control method includes: the operating conditions of the liquid ammonia direct injection engine include a first operating condition zone, a second operating condition zone, and a third operating condition zone. In the first operating condition zone, the load of the liquid ammonia direct injection engine is less than or equal to 40%; in the first operating condition zone, the injection pressure of the ammonia injection mechanism, the liquid ammonia injection duration of the ammonia injection mechanism, the fuel injection pressure of the intake and exhaust mechanism, and / or the fuel injection duration of the intake and exhaust mechanism are adjusted so that the hydrogen fuel substitution rate is in the range of 20-50%; In the second operating condition zone, the load of the liquid ammonia direct injection engine is greater than 40% and less than or equal to 65%; in the second operating condition zone, the injection pressure of the ammonia injection mechanism, the liquid ammonia injection duration of the ammonia injection mechanism, the fuel injection pressure of the intake and exhaust mechanism, and / or the fuel injection duration of the intake and exhaust mechanism are adjusted so that the hydrogen fuel substitution rate is in the range of 10-40%; In the third operating condition zone, the load of the liquid ammonia direct injection engine is greater than 65%; in the third operating condition zone, the injection pressure of the ammonia injection mechanism, the liquid ammonia injection duration of the ammonia injection mechanism, the fuel injection pressure of the intake and exhaust mechanism, and / or the fuel injection duration of the intake and exhaust mechanism are adjusted so that the hydrogen fuel substitution rate is in the range of 20-50%.

2. The zone control method for a liquid ammonia direct injection engine according to claim 1, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes: Both the injection section and the jet nozzle are located within the main combustion chamber.

3. The zone control method for a liquid ammonia direct injection engine according to claim 1, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes: multiple jet nozzles, each jet nozzle facing a different direction.

4. The zone control method for a liquid ammonia direct injection engine according to claim 1, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes: the housing having a mounting portion, the cylinder having a mounting hole corresponding to the mounting portion, and the mounting portion being connected to the mounting hole.

5. The zone control method for a liquid ammonia direct injection engine according to claim 4, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes: the cylinder block includes a cylinder liner and a cylinder head connected to the cylinder liner, and the cylinder head is provided with the mounting hole.

6. The zone control method for a liquid ammonia direct injection engine according to claim 1, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes: the intake and exhaust mechanism includes an intake duct and an exhaust duct respectively connected to the main combustion chamber, and a fuel injector for injecting fuel is connected to the intake duct.

7. The zone control method for a liquid ammonia direct injection engine according to claim 1, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes an engine in which the volume ratio of the passive pre-combustion chamber to the maximum volume of the main combustion chamber is less than 0.

1.

8. The zone control method for a liquid ammonia direct injection engine according to claim 1 or 3, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes an angle α between the central axis of the jet nozzle and the central axis of the cylinder block, where 20°≤α≤50°.

9. The zone control method for a liquid ammonia direct injection engine according to claim 1 or 3, characterized in that, The liquid ammonia direct injection engine with a passive pre-combustion chamber includes a jet nozzle with a diameter of d, where 0.1 mm ≤ d ≤ 1 mm.

10. The zone control method for a liquid ammonia direct injection engine according to claim 1, characterized in that, When the liquid ammonia direct injection engine is running, the intake air temperature is adjusted to be greater than 100°C.

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