Ammonia fuel combustion system, engine and combustion control method

Abstract

The present application relates to the technical field of internal combustion engines, and provides an ammonia fuel combustion system, comprising: a body; a piston installed in the body; a cylinder head installed at an opening position of the body, the cylinder head, the body and the piston defining a first combustion chamber; a first combustion part, comprising: a first injector arranged at a middle part of the cylinder head and used for injecting ammonia fuel into the first combustion chamber; a second combustion part, comprising: a second combustion chamber formed in the cylinder head and communicated with the first combustion chamber and used for igniting fuel in advance of the first combustion chamber; a second injector arranged in the second combustion chamber and used for injecting fuel into the second combustion chamber; and a jet hole formed in a surface of the cylinder head and the piston on the same side and used for forming jet flame of the fuel combusted in the second combustion chamber and introducing the jet flame into the first combustion chamber. The present application also provides a corresponding ammonia fuel engine and a combustion control method.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine technology, and in particular to an ammonia fuel combustion system, engine, and combustion control method. Background Technology

[0002] Ammonia fuel is a clean energy source that can effectively address the carbon emissions caused by combustion.

[0003] However, ammonia fuel has a high ignition temperature, high ignition energy, slow flame propagation speed, and narrow flammability limit, making it difficult to ignite and burn, and resulting in poor combustion performance and stability. Therefore, using compression autoignition requires a very high compression ratio. Pure ammonia fuel compression ignition combustion will encounter problems such as poor combustion stability or even "misfire" under low load conditions. At the same time, an excessively high engine compression ratio leads to poor operational stability and reliability.

[0004] Currently, the application of ammonia fuel in internal combustion engines is mainly through premixed ignition or dual-fuel combustion (such as diesel / ammonia dual-fuel). Premixed ignition suffers from low combustion efficiency and poor combustion stability; while dual-fuel combustion still requires a large amount of diesel fuel for ignition, resulting in poor carbon emission reduction. Summary of the Invention

[0005] In view of the existing technical problems, the present invention provides an ammonia fuel combustion system, an engine and a combustion control method, which at least partially solves the above technical problems.

[0006] One aspect of this disclosure provides an ammonia fuel combustion system, including a body; a piston mounted in the body; a cylinder head mounted at an opening in the body, the cylinder head, body, and piston defining a first combustion chamber; a first combustion section including: a first injector disposed in the center of the cylinder head for injecting ammonia fuel into the first combustion chamber; a second combustion section including: a second combustion chamber formed in the cylinder head and communicating with the first combustion chamber for igniting fuel prior to the first combustion chamber; a second injector disposed in the second combustion chamber for injecting fuel into the second combustion chamber such that the fuel ejected from the second injector burns under pressure prior to the ammonia fuel in the first combustion chamber; and a jet orifice formed on the surface of the cylinder head and the piston on the same side for forming a jet flame from the fuel burning in the second combustion chamber and introducing it into the first combustion chamber, such that the ammonia fuel in the first combustion chamber burns by diffusion combustion.

[0007] According to embodiments of this disclosure, it further includes: an intake manifold formed on the cylinder head; and an exhaust manifold formed on the other radial side of the cylinder head symmetrical to the intake manifold; wherein an intake valve is closably installed in the intake manifold; and an exhaust valve is closably installed in the exhaust manifold.

[0008] According to an embodiment of this disclosure, the first injector extends into the first combustion chamber along the axial direction of the cylinder head.

[0009] According to an embodiment of the present disclosure, the first injector has a plurality of nozzles evenly spaced circumferentially at its first axial end located in the first combustion chamber.

[0010] According to an embodiment of this disclosure, a groove is formed on the same side surface of the piston and cylinder head, the surface of the groove is smoothly disposed, and ammonia fuel injected by the nozzle of the first injector forms a vortex on the surface of the groove.

[0011] Another aspect of this disclosure provides an ammonia fuel engine, including an ammonia fuel combustion system; a monitoring unit adapted to monitor the position of the piston; and a control unit adapted to control the injection timing of the first injector and / or the second injector according to the position of the piston.

[0012] Another aspect of this disclosure provides a combustion control method, comprising: monitoring the position of a piston in an ammonia fuel engine; controlling the injection timing of a second injector based on the position of the piston; and controlling the injection timing of a first injector based on the state of a second combustion chamber.

[0013] According to embodiments of this disclosure, monitoring the position of a piston in an ammonia fuel engine includes obtaining the position of the piston based on the angle of the crankshaft rotation corresponding to the crankshaft rotation during one working cycle of the piston.

[0014] According to an embodiment of this disclosure, controlling the injection timing of the second injector based on the position of the piston includes injecting fuel by the second injector as the piston approaches top dead center during one working cycle of the piston.

[0015] According to an embodiment of this disclosure, controlling the injection timing of the first injector based on the state of the second combustion chamber includes igniting the fuel in the second combustion chamber to form a jet flame in the first combustion chamber, at which time the first injector injects ammonia fuel.

[0016] This disclosure provides an ammonia fuel combustion system, in which a first combustion chamber is formed by the cooperation of an engine block, piston, and cylinder head. A first combustion section and a second combustion section are respectively arranged inside the cylinder head. The first combustion section is used to input ammonia fuel into the first combustion chamber, and the second combustion section is used to pre-burn a portion of the fuel. The ammonia fuel in the first combustion chamber is then ignited by the jet flame formed by the pre-burned fuel.

[0017] This disclosure also provides an ammonia fuel engine that, while possessing the advantages of an ammonia fuel combustion system, controls the injection timing based on the piston position and state through the cooperation of a monitoring unit and a control unit. The opening and closing of the valves are used to compress and ignite the fuel in the second combustion chamber, thereby igniting the ammonia fuel in the first combustion chamber.

[0018] This disclosure also provides a combustion control method for an ammonia fuel engine to achieve a more stable combustion process and higher combustion efficiency of ammonia fuel. Attached Figure Description

[0019] Figure 1 This is a cross-sectional schematic diagram of an ammonia fuel combustion system according to an illustrative embodiment of the present disclosure;

[0020] Figure 2 yes Figure 1 A cross-sectional view of the illustrative embodiment shown from another angle;

[0021] Figure 3 yes Figure 1 A state diagram illustrating the fuel injection status of the combustion system in a schematic embodiment.

[0022] Figure 4 yes Figure 1 A bottom view of the cylinder head portion in the schematic embodiment shown;

[0023] Figure 5 This is a schematic block diagram of an ammonia fuel engine according to an exemplary embodiment of the present disclosure; and

[0024] Figure 6 This is a flowchart of a combustion control method for an ammonia fuel engine according to the present disclosure.

[0025] Figure Labels

[0026] 1. Piston;

[0027] 2. Organism;

[0028] 3. Cylinder head;

[0029] 4. First combustion chamber;

[0030] 5. Spray nozzle;

[0031] 6. First injector;

[0032] 7. Injector end cap;

[0033] 8. Second combustion chamber;

[0034] 9. Second injector;

[0035] 10. Jet orifice;

[0036] 11. Air intake;

[0037] 12. Intake valve;

[0038] 13. Exhaust valve; and

[0039] 14. Exhaust duct. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0041] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. 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.

[0042] 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.

[0043] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or systems having A, B, and C, etc.). Similarly, when using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or systems having A, B, and C, etc.).

[0044] Figure 1 This is a cross-sectional schematic diagram of an ammonia fuel combustion system according to an illustrative embodiment of the present disclosure; Figure 2 yes Figure 1 A cross-sectional view of the illustrative embodiment shown from another angle; Figure 3 yes Figure 1 A state diagram illustrating the fuel injection status of the combustion system in a schematic embodiment. Figure 4 yes Figure 1 A bottom view of the cylinder head portion in the schematic embodiment shown; Figure 5This is a schematic block diagram of an ammonia fuel engine according to an exemplary embodiment of the present disclosure; Figure 6 This is a flowchart of a combustion control method for an ammonia fuel engine according to this disclosure.

[0045] This disclosure provides an ammonia fuel combustion system, such as Figures 1 to 4 As shown, the system includes: a body 2; a piston 1 installed within the body 2; and a cylinder head 3 installed at an opening in the body 2. The body 2, piston 1, and cylinder head 3 define a first combustion chamber 4. The system also includes a first combustion section and a second combustion section. The first combustion section includes a first injector 6 disposed in the middle of the cylinder head 3. The second combustion section includes a second combustion chamber 8 formed within the cylinder head 3 and communicating with the first combustion chamber 4, a second injector 9 disposed within the second combustion chamber 8, and jet holes 10 formed on the surfaces of the cylinder head 3 and the piston 1 on the same side. The first injector 6 is used to inject ammonia fuel into the first combustion chamber 4; the second combustion chamber 8 is used to ignite the fuel before the first combustion chamber 4, so that the fuel ejected from the second injector 9 burns under pressure before the fuel in the first combustion chamber 4; the second injector 9 is used to inject fuel into the second combustion chamber 8, and the jet orifice 10 is used to form a jet flame of the fuel burning in the second combustion chamber 8 and introduce it into the first combustion chamber 4, igniting the ammonia fuel mist formed by the ammonia fuel in the first combustion chamber 4, and causing the ammonia fuel in the first combustion chamber 4 to burn in a diffusion combustion manner.

[0046] In detail, the second combustion section uses highly reactive fuel, which is characterized by being more easily combusted than ammonia fuel, and further preferably being easily ignited by compression under the pressure and temperature conditions of the second combustion chamber.

[0047] Furthermore, the first combustion section uses ammonia fuel to form a fuel mist that is ignited by the jet flame formed in the second combustion section. The fuel mist is not limited to any particular type of fuel; in addition to being liquid, the fuel should also include gaseous or supercritical fluid states.

[0048] Furthermore, the second combustion section includes, but is not limited to, the forms described above. This second combustion section requires a corresponding second injector 9, and the second combustion chamber 8 and the first combustion chamber 4 are disposed within a single space. The highly reactive fuel injected by the second injector 9 burns before the ammonia fuel in the first combustion chamber 4, forming a jet flame to ignite the fuel.

[0049] According to embodiments of this disclosure, the combustion device further includes an intake manifold 11 formed on the cylinder head 3, and an exhaust manifold 14 symmetrically arranged on the cylinder head 3 with respect to the intake manifold 11. An intake valve 12 is installed in the intake manifold 11 and an exhaust valve 13 is installed in the exhaust manifold 14.

[0050] According to an embodiment of this disclosure, the first injector 6 extends along the axial direction of the cylinder head 3 into the first combustion chamber 4.

[0051] According to embodiments of this disclosure, such as Figure 3 and Figure 4 As shown, the first injector 6 is located in the first combustion chamber 4, and multiple nozzles 5 are uniformly spaced along the circumference at its first axial end.

[0052] In detail, the number of nozzles 5 is six to eight, and the above six nozzles 5 are evenly spaced along the circumference.

[0053] In detail, the first injector 6 is fixed to the end cap by the injector end cap 7.

[0054] Furthermore, the number of nozzles 5 can be designed according to actual fuel injection requirements and flow rates. It should be understood that the embodiments of this disclosure are not limited thereto.

[0055] For example, the number of nozzles 5 is different from other numbers.

[0056] Furthermore, the position of the nozzle 5 can also be designed according to the type of fuel and its relative position to the second combustion section.

[0057] In detail, the lower end of the second combustion chamber 8 is located inside the first combustion chamber 4.

[0058] Furthermore, the second combustion chamber 8 is an offset second combustion chamber relative to the first combustion chamber 4.

[0059] Furthermore, each of the multiple jet holes 10 formed in the second combustion chamber 8 can be designed individually according to actual needs. For example, the position, number, and parameters (including but not limited to angle, diameter, and length) of the jet holes 10 should be designed to ensure that the second combustion chamber 8 can form a jet flame and that the jet flame can effectively ignite the fuel in the first combustion chamber 4.

[0060] For example, the number of jet holes 10 is the same as the number of nozzles 5 in the first burner 6. Furthermore, the paths of the jet flame formed by the jet holes 10 and the fuel ejected from the nozzles 5 partially overlap.

[0061] For example, the number of jet holes 10 is inconsistent with the number of nozzles 5 of the first burner 6.

[0062] For example, the downward tilt angle of the jet orifice 10 near the first injector 6 is smaller than that of the jet orifice 10 on the other side, so that the jet flames ejected from both sides can come into contact with and effectively ignite the corresponding ammonia fuel mist, thereby improving the ignition effect of the flame jet on the fuel in the first combustion chamber 4. It should be understood that the embodiments of this disclosure are not limited thereto.

[0063] For example, the angles and positions of each jet orifice 10 are consistent.

[0064] For example, the speed of fuel ejected from the jet orifice 10 can be controlled by the overall design of parameters such as the length, diameter and angle of the jet orifice 10.

[0065] According to an embodiment of this disclosure, in the plane formed by the radial direction of the cylinder head 3, the line connecting the first combustion section and the second combustion section is perpendicular to the line connecting the intake passage 11 and the exhaust passage 14. This design allows the second combustion section to be offset relative to the first combustion section, which facilitates the design objective of igniting the first combustion section by designing the parameters of the nozzle 5 and the jet hole 10.

[0066] According to an embodiment of this disclosure, a groove is formed on the same side surface of the piston 1 and the cylinder head 3. The surface of the groove is smoothly disposed, and the fuel injected by the nozzle 5 of the first injector forms a vortex on the surface of the groove.

[0067] In detail, grooves are formed on the same side surface of the piston and cylinder head, and the bottom of the grooves is smoothly set with a rounded transition.

[0068] Furthermore, a protrusion is formed at the center of the groove and at the position of the orthographic projection of the first combustion section, and the protrusion is integrally formed with the bottom of the groove. This allows the fuel, after being injected into the groove, to be blocked by the bottom of the groove and extend radially outward along the bottom to form a vortex. It should be understood that the embodiments of this disclosure are not limited thereto.

[0069] For example, the shape of the groove should be designed according to the position of the first combustion section and the position of the nozzle 5 formed by the first injector 6.

[0070] Furthermore, since piston 1 moves along the body 2, the shape of the groove should also be designed according to the position of piston 1 relative to the body 2.

[0071] For example, the shape of the groove should be designed to determine what kind of vortex the fuel injected by the first injector 6 can form in the groove when the piston 1 moves upward to a certain position.

[0072] According to another aspect of this disclosure, an ammonia fuel engine is also provided, such as Figure 6 As shown, the system includes an ammonia fuel combustion system, a monitoring unit, and a control unit. The monitoring unit monitors the position of piston 1, and the control unit controls the injection timing of the first injector 6 and / or the second injector 9 based on the position of piston 1.

[0073] In detail, the control unit also controls the opening and closing of the intake valve 12 and / or the exhaust valve 13.

[0074] According to another aspect of this disclosure, a combustion control method for an ammonia fuel engine is also provided, such as... Figure 6 As shown, it includes: monitoring the position of piston 1 of the ammonia fuel engine; controlling the injection timing of the second injector 9 according to the position of piston 1; and controlling the injection timing of the first injector 6 according to the state of the second combustion chamber 8.

[0075] According to an embodiment of this disclosure, monitoring the position of piston 1 in an ammonia fuel engine includes obtaining the position of piston 1 based on the angle of the crankshaft rotation corresponding to the crankshaft linked to piston 1 during one working cycle of piston 1.

[0076] According to an embodiment of the present disclosure, controlling the injection timing of the second injector 9 based on the position of the piston 1 includes injecting fuel from the second injector 9 as the piston 1 approaches top dead center during one working cycle of the piston 1.

[0077] According to an embodiment of this disclosure, controlling the injection timing of the first injector 6 based on the state of the second combustion chamber 8 includes igniting the fuel in the second combustion chamber 8 to form a jet flame in the first combustion chamber 4, while the first injector 6 injects ammonia fuel.

[0078] In detail, piston 1 first moves downwards from top dead center. At this time, intake valve 12 is open and exhaust valve 13 is closed, allowing fresh air to enter the first combustion chamber 4 and the second combustion chamber 8 through intake manifold 11. When piston 1 passes bottom dead center, intake valve 12 closes, and piston 1 moves upwards, compressing the air in the cylinder, causing its temperature and pressure to rise continuously. When piston 1 approaches top dead center, the second injector 9 begins to inject highly reactive fuel. The highly reactive fuel ignites spontaneously under high temperature and pressure, and the heat released by fuel combustion causes a sharp increase in temperature and pressure in the second combustion chamber 8. Therefore, the pressure difference between the second combustion chamber 8 and the first combustion chamber 4 gradually increases. Under the action of pressure difference, the combustion flame in the second combustion chamber 8 will be ejected from the jet hole 10 to form a jet flame; at the same time, the first injector 6 also begins to inject ammonia fuel. Due to the high injection pressure, the ammonia fuel spray will be sprayed to the edge of the first combustion chamber 4, so that the jet flame can ignite the combustible mixture at the end of the spray; after the combustible mixture at the end of the spray in the first combustion chamber is ignited, a diffusion combustion flame is formed. The fuel combustion releases a large amount of heat, pushing the piston 1 to move downward and output mechanical work; when the piston 1 moves to near the bottom dead center, the exhaust valve 13 opens, and the piston 1 moves upward to expel the exhaust gas in the combustion chamber, completing the entire working process.

[0079] According to the ammonia fuel combustion system, ammonia fuel engine, and combustion control method of the ammonia fuel engine provided in this disclosure: 1. The jet flame generated by the combustion of highly reactive fuel in the second combustion chamber ignites the ammonia fuel in the first combustion chamber, enabling diffusion combustion of the ammonia fuel. Diffusion combustion has high efficiency; therefore, the ammonia fuel combustion system and ammonia fuel engine provided in this disclosure have high combustion efficiency and thermal efficiency. 2. The ignition effect of the jet flame can significantly improve the ignition and combustion stability of ammonia fuel under low-load conditions. 3. The amount of fuel entering the first and / or second combustion chambers can be adjusted according to real-time load changes to effectively improve the stable combustion of the combustion system under all operating conditions. This allows for increasing the amount of fuel in the second combustion chamber under low-load conditions, enhancing the ignition effect of the jet flame, and effectively improving combustion stability. Under high-load conditions, the fuel injection strategy is optimized to effectively prevent excessively rough combustion.

[0080] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. An ammonia fuel combustion system, comprising: Body (2); Piston (1) is installed inside the body (2); Cylinder head (3) is installed at the opening of the engine block (2), and the cylinder head (3), engine block (2) and piston (1) define a first combustion chamber (4). The first combustion section includes: The first injector (6) is located in the middle of the cylinder head (3) and is used to inject ammonia fuel into the first combustion chamber (4). The first injector (6) extends into the first combustion chamber (4) along the axial direction of the cylinder head (3). The end of the first injector (6) located in the first combustion chamber (4) is provided with a plurality of nozzles (5) evenly spaced in the circumferential direction. A groove is formed on the same side surface of the piston (1) and the cylinder head (3). The surface of the groove is smooth. A protrusion is formed at the middle of the groove and the position of the orthographic projection of the first combustion part. The ammonia fuel injected by the nozzles (5) of the first injector (6) forms a vortex on the surface of the groove. The second combustion section includes: The second combustion chamber (8) is formed in the cylinder head (3) and communicates with the first combustion chamber (4) to ignite the fuel before the first combustion chamber (4); A second injector (9) is disposed within the second combustion chamber (8) for injecting fuel into the second combustion chamber (8), such that the fuel injected from the second injector burns under pressure before the ammonia fuel in the first combustion chamber; and The jet orifice (10) is formed on the surface of the cylinder head (3) facing the piston (1) to form a jet flame of the fuel burning in the second combustion chamber (8) and introduce it into the first combustion chamber (4), igniting the ammonia fuel in the first combustion chamber (4) and causing the ammonia fuel in the first combustion chamber (4) to burn in a diffusion combustion manner; The jet flame formed by the jet hole (10) and the path of the fuel ejected from the nozzle (5) partially overlap.

2. The ammonia fuel combustion system according to claim 1, further comprising: An intake manifold (11) is formed on the cylinder head (3); as well as An exhaust passage (14) is formed on the other radial side of the cylinder head (3) that is symmetrical to the intake passage (11); The intake duct (11) is equipped with an intake valve (12) that can be opened and closed; the exhaust duct (14) is equipped with an exhaust valve (13) that can be opened and closed.

3. An ammonia-fueled engine, comprising: The ammonia fuel combustion system as described in claim 1 or 2; The monitoring unit is suitable for monitoring the position of the piston (1); as well as The control unit is adapted to control the injection timing of the first injector (6) and / or the second injector (9) according to the position of the piston (1).

4. A combustion control method for an ammonia fuel engine according to claim 3, comprising: Monitor the position of piston (1) in the ammonia fuel engine; The timing of oil injection by the second injector (9) is controlled according to the position of the piston (1); as well as The timing of fuel injection of the first injector (6) is controlled according to the state of the second combustion chamber (8).

5. The combustion control method according to claim 4, wherein, Monitoring the position of the piston (1) of an ammonia fuel engine includes obtaining the position of the piston (1) based on the angle of the crankshaft rotation corresponding to the crankshaft linked to the piston (1) during one working cycle of the piston (1).

6. The combustion control method according to claim 5, wherein, Controlling the injection timing of the second injector (9) according to the position of the piston (1) includes injecting fuel by the second injector (9) during one working cycle of the piston (1) as the piston (1) approaches the top dead center.

7. The combustion control method according to claim 6, wherein, Controlling the injection timing of the first injector (6) according to the state of the second combustion chamber (8) includes the following: after the fuel in the second combustion chamber (8) is ignited, a jet flame is formed in the first combustion chamber (4), and at the same time, the first injector (6) injects ammonia fuel.

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