Combustion system of hydrogen engine, hydrogen engine and design method of combustion system

Abstract

The invention discloses a combustion system of a hydrogen engine, the hydrogen engine and a design method of the combustion system. The combustion system comprises a cylinder cover and a hydrogen spraying assembly. The cylinder cover and the piston are arranged in the axis direction of the piston, and a combustion chamber is formed between the cylinder cover and the piston. The cylinder cover is provided with two air inlets and two air outlets, and the air inlets and the air outlets are communicated with the combustion chamber; the first gas inlet channel and the second gas inlet channel are channels for providing rolling flowing gas for the combustion chamber; the hydrogen spraying assembly is installed on the cylinder cover, located between the gas inlet and the gas outlet, communicated with the combustion chamber and used for spraying hydrogen into the combustion chamber in the direction facing the gas outlet. The first air inlet channel and the second air inlet channel provide rolling air for the combustion chamber, the hydrogen spraying assembly sprays hydrogen towards the exhaust port, and the hydrogen can impact the inner wall of the cylinder sleeve in the spraying process, so that the hydrogen and rolling air form a vortex at the edge of the cylinder sleeve, and the hydrogen and the air in the cylinder are mixed more uniformly.

Description

Technical Field

[0001] This invention relates to the technical field of hydrogen engines, and particularly to a combustion system for a hydrogen engine, a hydrogen engine, and a design method for the combustion system. Background Technology

[0002] Hydrogen, as a renewable and clean energy source, can be obtained directly from water. Compared with methane and gasoline, hydrogen has advantages in internal combustion engine applications, such as low unit mass, high calorific value, low ignition energy, wide ignition threshold, fast flame propagation speed, and low emissions. Therefore, hydrogen engines have been developed rapidly.

[0003] Currently, most hydrogen engines use port injection for air intake. However, due to hydrogen's low density, low ignition energy, and wide ignition limit, hydrogen engines are prone to abnormal combustion phenomena such as pre-ignition and backfire. To address this issue, some hydrogen engines have changed the hydrogen supply method from port injection to direct injection into the cylinder. While direct injection can solve the backfire problem, it results in a shorter hydrogen-air mixing time, leading to uneven distribution of the air-fuel mixture within the cylinder. Summary of the Invention

[0004] In view of this, the present invention provides a combustion system for a hydrogen engine to alleviate the problem of uneven mixing of hydrogen and air. Furthermore, the present invention also provides a hydrogen engine having the above-described combustion system and a design method for the combustion system of the above-described hydrogen engine.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A combustion system for a hydrogen engine, comprising:

[0007] A cylinder head, wherein the cylinder head and the piston are arranged along the axial direction of the piston, and a combustion chamber is formed between the cylinder head and the piston; the cylinder head is provided with at least two air intake ports and at least two exhaust ports, and both the air intake ports and the exhaust ports are in communication with the combustion chamber;

[0008] The first and second air intakes are connected to the air inlet, and the first and second air intakes are channels for providing rolling flow of gas to the combustion chamber.

[0009] A hydrogen injection assembly is mounted on the cylinder head and located between the intake port and the exhaust port. The hydrogen injection assembly communicates with the combustion chamber and is used to inject hydrogen into the combustion chamber in a direction toward the exhaust port to form a vortex at the edge of the combustion chamber.

[0010] Preferably, in the combustion system of the hydrogen engine described above, the hydrogen injection assembly includes a hydrogen injector and a guide sleeve; the hydrogen injector is mounted on the cylinder head, and the outlet end of the hydrogen injector extends into the combustion chamber; the guide sleeve is fitted onto the outlet end of the hydrogen injector, and the guide sleeve has a guide opening facing the exhaust port.

[0011] Preferably, in the combustion system of the hydrogen engine described above, the guide port is located on the side of the guide sleeve near the exhaust port and is arranged radially along the guide sleeve.

[0012] Preferably, in the combustion system of the hydrogen engine described above, the cylinder head is a flat-top cylinder head; and within the plane of the cylinder head, the angle β between the projection of the guide port's axis onto the cylinder head and the line connecting it to the horizontal direction is 30° to 60°.

[0013] Wherein, the projection of the axis of the guide port onto the cylinder head is the projection of the axis of the guide port onto the cylinder head in a direction perpendicular to the cylinder head; the horizontal direction is the direction of the line connecting the adjacent intake port and exhaust port located on the cylinder head.

[0014] Preferably, in the combustion system of the hydrogen engine described above, the guide port is located at the bottom of the guide sleeve and is disposed near the exhaust port, and the guide port is a through hole inclined relative to the axial direction of the guide sleeve.

[0015] Preferably, in the combustion system of the hydrogen engine described above, the angle α between the axis of the guide port and the axis of the guide sleeve is 10° to 50°.

[0016] Preferably, in the combustion system of the hydrogen engine described above, both the first intake manifold and the second intake manifold are straight pipes, and the ends of the first intake manifold and the second intake manifold are bent and inserted into the corresponding intake ports. The ends of the first intake manifold and the second intake manifold both face the bottom of the combustion chamber, and the axis of the intake port is perpendicular to the tangential direction of the edge of the cylinder head.

[0017] Preferably, in the combustion system of the hydrogen engine described above, the inner wall of the air intake near the exhaust port has a first included angle A with the lower surface of the cylinder head;

[0018] The inner wall of the side of the air intake port away from the exhaust port has a second included angle B with the lower surface of the cylinder head, and the first included angle A is smaller than the second included angle B;

[0019] The lower surface of the cylinder head is the side of the cylinder head opposite to the piston.

[0020] Preferably, in the combustion system of the hydrogen engine described above, the first included angle A is 30° to 40°; and the second included angle B is 50° to 70°.

[0021] Preferably, the combustion system of the hydrogen engine described above further includes an exhaust duct, which includes a first branch and a second branch. One end of the first branch and one end of the second branch are respectively connected to an exhaust port, and the other ends of the first branch and the second branch are connected as one unit.

[0022] A hydrogen engine includes a combustion system, said combustion system being any of the hydrogen engines described above.

[0023] A design method for a combustion system of a hydrogen engine, used in any of the above-mentioned combustion systems, includes: building a combustion system simulation model, and setting a preset swirl ratio and a preset tumble ratio in the cylinder;

[0024] Adjust the intake manifold structure until the simulated tumble ratio in the cylinder obtained from the simulation reaches the preset tumble ratio.

[0025] After hydrogen is injected, the simulated vortex ratio in the cylinder is obtained through simulation. If the simulated vortex ratio is lower than the preset vortex ratio, at least one of conditions one and two can be performed until the simulated vortex ratio reaches the preset vortex ratio. Condition one is to reduce the orifice diameter of the guide port of the hydrogen injection assembly of the combustion system, and condition two is to increase the angle α between the axis of the guide port and the axis of the guide sleeve of the hydrogen injection assembly.

[0026] Adjust the injection direction of the hydrogen injection assembly until the gas in the cylinder is evenly mixed.

[0027] Preferably, in the above-mentioned design method for the combustion system of a hydrogen engine, the step of building a combustion system simulation model includes: building an initial simulation model;

[0028] The initial simulation model is corrected, and the cylinder pressure, heat release rate and tumble ratio data obtained from the simulation calculation are compared with the experimental results. If the calibration error exceeds the preset range, the parameter settings and mesh of the simulation model are adjusted until the error meets the limit.

[0029] Once the error meets the limit, the mesh settings and parameter settings in the simulation model are standardized to obtain the combustion system simulation model.

[0030] This invention discloses a combustion system for a hydrogen engine. A first intake manifold and a second intake manifold provide swirling air to the combustion chamber. A hydrogen injection assembly injects hydrogen towards the exhaust port, meaning the hydrogen injection assembly guides the hydrogen flow towards the exhaust side of the hydrogen engine. As a result, the hydrogen impacts the inner wall of the cylinder liner during injection, causing the hydrogen and swirling gas to form a vortex at the edge of the cylinder liner. That is, the middle of the combustion chamber is filled with swirling gas, while the gas at the edge flows in a vortex. Under the action of the vortex, the hydrogen and the air in the cylinder can be mixed more evenly.

[0031] Furthermore, embodiments of the present invention also disclose a hydrogen engine having the combustion system of the aforementioned hydrogen engine and a design method for the combustion system of the aforementioned hydrogen engine. Therefore, the hydrogen engine designed by the design method of the hydrogen engine and combustion system also has the aforementioned technical effects. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a bottom view of the combustion system of the hydrogen engine disclosed in an embodiment of the present invention;

[0034] Figure 2 This is a front sectional view of the combustion system of a hydrogen engine disclosed in an embodiment of the present invention;

[0035] Figure 3 This is a front sectional view of the guide sleeve of the combustion system of the hydrogen engine disclosed in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the tumble ratio and swirl ratio in the combustion chamber of a hydrogen engine under different piston operating conditions as disclosed in an embodiment of the present invention;

[0037] Figure 5 This is a diagram showing the relationship between the included angle α and the eddy current ratio as disclosed in an embodiment of the present invention;

[0038] Figure 6 This is a flowchart illustrating the design method of the combustion system of a hydrogen engine disclosed in an embodiment of the present invention.

[0039] Among them, 1-cylinder head, 11-intake port, 12-exhaust port, 2-intake manifold, 21-first intake manifold, 22-second intake manifold, 3-exhaust manifold, 31-first branch, 32-second branch, 4-hydrogen injection assembly, 41-hydrogen injector, 42-guide sleeve, 421-guide port, 5-spark plug, 6-piston, 7-combustion chamber. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Hereinafter, the terms "first" and "second" are used 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 as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0042] Hydrogen, as a renewable and clean energy source, can be obtained directly from water. Compared with methane and gasoline, hydrogen has advantages in internal combustion engine applications, such as low unit mass, high calorific value, low ignition energy, wide ignition threshold, fast flame propagation speed, and low emissions. Therefore, hydrogen engines have been developed rapidly.

[0043] Currently, most hydrogen engines use port injection for air intake, where hydrogen is injected into the intake manifold to premix with the existing air before entering the cylinder. However, due to hydrogen's low density, low ignition energy, and wide ignition limit, hydrogen engines are prone to abnormal combustion phenomena such as pre-ignition and backfire. To address this issue, some hydrogen engines have changed the hydrogen supply method from port injection to direct injection into the cylinder. While direct injection can solve the backfire problem, it results in a shorter hydrogen-air mixing time, leading to uneven distribution of the air-fuel mixture within the cylinder.

[0044] Based on the above-mentioned technical problems, this embodiment discloses a combustion system for a hydrogen engine to alleviate the problem of uneven mixing of hydrogen and air.

[0045] like Figure 1 and Figure 2 As shown, the combustion system of the hydrogen engine in this embodiment includes: cylinder head 1, cylinder liner (not shown in the figure), piston 6, intake manifold 2, exhaust manifold 3, hydrogen injection assembly 4, and spark plug 5.

[0046] The piston 6 is disposed inside the cylinder liner and is movable within the cylinder liner along the axial direction of the cylinder liner. The cylinder head 1 is disposed on the upper surface of the cylinder liner along the axial direction, and the cylinder head 1 and the piston 6 are arranged opposite each other along the axial direction of the piston 6. A combustion chamber 7 is formed between the piston 6 and the cylinder head 1, and a spark plug 5 is disposed on the top of the combustion chamber 7 on the cylinder head 1.

[0047] Optionally, the cylinder head 1 in this embodiment can be a flat-top cylinder head, thereby utilizing the cylinder head of a diesel engine to reduce the conversion cost of converting an existing diesel engine into a hydrogen engine.

[0048] The cylinder head 1 has at least two intake ports 11 and at least two exhaust ports 12 at at least one cylinder liner, and both the intake ports 11 and the exhaust ports 12 are in communication with the combustion chamber 7. The hydrogen injection assembly 4 and the spark plug 5 are both disposed on the cylinder head 1.

[0049] In this embodiment, at least one cylinder liner of the cylinder head 1 is provided with at least one set of intake and exhaust channels, which include an intake passage 2 and an exhaust passage 3. The intake passage 2 includes a first intake passage 21 and a second intake passage 22, and the exhaust passage 3 includes a first branch 31 and a second branch 32. The first intake passage 21 and the second intake passage 22 are respectively connected to an intake port 11, and the first branch 31 and the second branch 32 are respectively connected to an exhaust port 12.

[0050] In this embodiment, the first air intake 21 and the second air intake 22 are channels for providing rolling flow gas (such as air or oxygen, hereinafter referred to as air) to the combustion chamber 7.

[0051] As can be seen, an intake valve is provided at the air inlet 11, and the air inlet 11 can be opened or closed by moving the intake valve; an exhaust valve is provided at the exhaust outlet 12, and the exhaust outlet 12 can be opened or closed by moving the exhaust valve.

[0052] The hydrogen injection assembly 4 is located at the edge of the cylinder head 1 and is situated in the area between the intake port 11 and the exhaust port 12. The hydrogen injection assembly 4 is connected to the combustion chamber 7 and is used to inject hydrogen into the combustion chamber 7 in the direction of the exhaust port 12.

[0053] Since the hydrogen injection assembly 4 injects hydrogen towards the exhaust port 12, that is, the hydrogen injection assembly 4 guides the hydrogen flow towards the exhaust side of the hydrogen engine, the hydrogen will impact the inner wall of the cylinder liner during the injection process, causing the hydrogen and the tumbling gas to form a vortex at the edge of the cylinder liner, thereby making the hydrogen and the air in the cylinder mix more evenly.

[0054] Since the first intake duct 21 and the second intake duct 22 provide swirling air to the combustion chamber 7, and the hydrogen injected by the hydrogen injection assembly 4 forms a vortex with the air at the edge of the combustion chamber 7, the high-speed swirling area in the combustion chamber 7 in this embodiment is located near the spark plug 5, which makes the hydrogen combustion fast in the early stage and slow in the later stage, increases the in-cylinder vortex, accelerates the later combustion speed, and improves the engine thermal efficiency.

[0055] It should be noted that the spark plug 5 in this article is located in the middle of the cylinder head 1.

[0056] Figure 4 This diagram illustrates the airflow patterns within the combustion chamber of the combustion system under different piston operating conditions in this embodiment. The solid line represents the tumble ratio within combustion chamber 7, and the dashed line represents the vortex ratio within combustion chamber 7. As can be seen from the diagram, in this embodiment's combustion system, after the hydrogen injection assembly 4 injects hydrogen, vortices are formed within the combustion chamber, causing the airflow within the combustion chamber to primarily operate in a tumble manner, generating vortices at the edges.

[0057] like Figure 1 As shown, the hydrogen injection assembly 4 in this embodiment includes a hydrogen injector 41 and a guide sleeve 42.

[0058] The hydrogen injector 41 is inserted into the cylinder head 1. Optionally, the cylinder head 1 has a mounting hole, and the hydrogen injector 41 is sealed and inserted into the mounting hole. The outlet end of the hydrogen injector 41 extends into the combustion chamber 7 for injecting hydrogen into the combustion chamber 7.

[0059] The guide sleeve 42 is fitted onto the outlet end of the hydrogen injector 41. Optionally, the guide sleeve 42 and the hydrogen injector 41 can be threaded, bonded, or snap-fitted together. In some embodiments, the direct D of the guide sleeve 42 is adapted to the outlet end of the hydrogen injector 41 to achieve a sealed connection between the guide sleeve 42 and the hydrogen injector 41.

[0060] The guide sleeve 42 has a guide opening 421, which faces the exhaust port 12.

[0061] In some embodiments, the guide port 421 may be located on the side of the guide sleeve 42 near the exhaust port 12, and the guide port 421 may be arranged radially along the guide sleeve 42 so that hydrogen is ejected toward the exhaust side.

[0062] It should be noted that the guide port 421 is located on the side of the guide sleeve 42, which can increase the collision force between the injected hydrogen and the side wall of the cylinder liner.

[0063] Combination Figure 1 As shown, since the cylinder head 1 in this embodiment can be a flat-top cylinder head, the angle β between the projection of the axis of the guide port 421 onto the cylinder head 1 and the line connecting the horizontal direction in the plane of the cylinder head 1 is 30° to 60°.

[0064] The projection of the axis of the guide port 421 onto the cylinder head 1 is the projection of the axis of the guide port 421 onto the cylinder head 1 in a direction perpendicular to the cylinder head 1. The horizontal direction is the direction of the line connecting the adjacent intake port 11 and exhaust port 12 located on the cylinder head 1; it can be understood as the direction of the line connecting the centers of the intake port 11 and exhaust port 12 on the cylinder head 1. The horizontal direction in this text is merely a name and is not limited to the direction of a horizontal line.

[0065] In this embodiment, the angle of the guide port 421 toward the exhaust port 12 is limited so as to use the tumble flow in the cylinder to provide driving force for the hydrogen, so that the hydrogen flows faster in the combustion chamber 7, which is beneficial to increase the vortex effect formed by the hydrogen.

[0066] like Figure 3 As shown, the guide port 421 is located at the bottom of the guide sleeve 42 and is set near the exhaust port 12. The guide port 421 is a through hole that is inclined relative to the axial direction of the guide sleeve 42 so that hydrogen gas is sprayed out towards the exhaust side.

[0067] It should be noted that the guide port 421 is located at the bottom of the guide sleeve 42 and is set at an angle, so that the injected hydrogen has a vertical velocity, which increases the disturbance force between hydrogen and air and improves the mixing effect of hydrogen and air.

[0068] Optionally, the angle α between the axis of the guide port 421 and the axis of the guide sleeve 42 is 10° to 50°, so that hydrogen can be injected through the guide port 421 toward the side wall of the cylinder liner.

[0069] Combination Figure 5 As can be seen from simulation experiments, the eddy current ratio gradually increases as the angle α between the axis of the guide port and the axis of the guide sleeve of the hydrogen injection assembly gradually increases along the direction of the arrow in the figure. Therefore, those skilled in the art can select the value of the angle α according to different requirements. It should be noted that... Figure 5 The corresponding value along the direction of the arrow will gradually increase.

[0070] The guide opening 421 is not limited to a round hole or a rectangular hole, and the diameter c of the guide opening 421 can be set according to different needs, which is not specifically limited here.

[0071] This embodiment provides two different arrangements of the guide port 421. Those skilled in the art can choose the arrangement of the guide port 421 according to different requirements.

[0072] like Figure 1As shown, both the first intake manifold 21 and the second intake manifold 22 are straight pipes, and the ends of the first intake manifold 21 and the second intake manifold 22 are bent and inserted into the corresponding intake ports 11. This can be understood as the end of the first intake manifold 21 being inserted into one intake port 11 of the cylinder head 1, and the end of the second intake manifold 22 being inserted into the other intake port 11 of the cylinder head 1. Optionally, the ends of the first intake manifold 21 and the second intake manifold 22 both face the bottom of the combustion chamber 7. Furthermore, in this embodiment, the axis of the intake port 11 is perpendicular to the edge of the cylinder head 1 and tangentially, which reduces the tangential component of both the first intake manifold 21 and the second intake manifold 22, allowing the air entering the combustion chamber 7 to move in a tumbling manner. Thus, the first intake manifold 21 and the second intake manifold 22 can be formed as pipes providing tumbling flow gas to the combustion chamber 7.

[0073] It should be noted that the specific shapes of the first air intake 21 and the second air intake 22 can be set according to different needs, as long as the first air intake 21 and the second air intake 22 can both enable the gas entering the combustion chamber 7 to move in a tumbling manner.

[0074] like Figure 2 As shown, the inner wall of the intake port 11 on the side closer to the exhaust port 12 has a first included angle A with the lower surface of the cylinder head 1; the inner wall of the intake port 11 on the side away from the exhaust port 12 has a second included angle B with the lower surface of the cylinder head 1, and the first included angle A is smaller than the second included angle B.

[0075] In this embodiment, the first included angle A of the air intake 11 is smaller than the second included angle B, which makes the side wall of the air intake 11 near the exhaust port 12 smoother radially. The side wall of the air intake 11 near the exhaust port 12 is closer to the shape of the valve seat of the intake valve, so that the area of ​​the side wall of the air intake 11 near the exhaust port 12 that is in sealing contact with the intake valve is larger. In order to seal with the valve seat of the intake valve, the side wall of the air intake 11 away from the exhaust port 12 has a smaller area for sealing contact with the valve seat.

[0076] Combining the above settings and Figure 2 As shown, during the movement of the intake valve, the intake port 11 is open. The flow area of ​​the side wall of the intake port 11 near the exhaust port 12 is larger than that of the side wall of the intake port 11 away from the exhaust port 12. This allows more gas to flow from the side wall of the intake valve near the exhaust port 12, thus enhancing the tumble effect.

[0077] In some embodiments, the first included angle A may be 30° to 40°; the second included angle B may be 50° to 70°.

[0078] The specific values ​​of the first included angle A and the second included angle B can be set according to different needs, and all are within the protection range.

[0079] Figure 1 The exhaust duct 3 shown includes a first branch 31 and a second branch 32. One end of the first branch 31 and one end of the second branch 32 are respectively connected to an exhaust port 12, and the other ends of the first branch 31 and the second branch 32 are connected as one unit.

[0080] During the movement of the exhaust valve at the first branch 31, the exhaust port 12 connected to the first branch 31 can be closed or opened; during the movement of the exhaust valve at the second branch 32, the exhaust port 12 connected to the second branch 32 can be closed or opened.

[0081] The first branch 31 and the second branch 32 are connected as one unit, which simplifies the path and facilitates the collection and utilization of exhaust gas.

[0082] In addition, this embodiment also discloses a hydrogen engine, including a combustion system, and the combustion system is the same as the combustion system disclosed in the above embodiments. Therefore, the hydrogen engine with this combustion system also has all the above-mentioned technical effects, which will not be described in detail here.

[0083] This embodiment also discloses a design method for the combustion system of a hydrogen engine, which can be used for the design of the combustion system of the aforementioned hydrogen engine.

[0084] like Figure 6 As shown, the design method for the combustion system of a hydrogen engine includes:

[0085] S1: Build a combustion system simulation model and set the preset swirl ratio and preset tumble ratio in the cylinder.

[0086] The process of building a combustion system simulation model may include:

[0087] S11: Build the initial simulation model.

[0088] An initial simulation model can be built based on the existing experimental data. The initial simulation model includes the size parameters of the air intake (including the first air intake and the second air intake) as well as the size of the hydrogen injector and the guide port in the hydrogen injection assembly.

[0089] S12: Correct the initial simulation model.

[0090] The cylinder pressure, heat release rate, and tumble ratio data obtained from the simulation calculations are compared with the experimental results. If the calibration error exceeds the preset range, that is, if the difference between the simulated cylinder pressure data and the experimental results exceeds the preset range of cylinder pressure, the difference between the simulated heat release rate data and the experimental results exceeds the preset range of heat release rate, and the difference between the simulated tumble ratio data and the experimental results exceeds the preset range of tumble ratio, then the parameter settings and mesh of the simulation model are adjusted until the error meets the limit, that is, the error is within the preset range.

[0091] S13: Build a simulation model.

[0092] Once the error meets the limit, the mesh settings and parameter settings in the simulation model will be standardized.

[0093] If the cylinder pressure, heat release rate, and tumble ratio data obtained from the simulation calculation are within the preset range of the calibration error with the test structure, then the numerical range of the parameters and the mesh settings of the simulation model are retained, and a corresponding adjustment menu is generated in the simulation interface to build the combustion system simulation model.

[0094] S2: Ensure that the simulated tumble ratio is the same as the preset tumble ratio.

[0095] Adjust the intake manifold structure until the simulated tumble ratio in the cylinder obtained from the simulation reaches the preset tumble ratio.

[0096] In this embodiment, the simulated tumble ratio can be adjusted by adjusting the size of at least one of the first included angle A and the second included angle B, so that the simulated tumble ratio reaches the preset tumble ratio.

[0097] Wherein, the first included angle A is the angle between the inner wall of the intake port on the side closer to the exhaust port and the lower surface of the cylinder head, and the second included angle B is the angle between the inner wall of the intake port on the side farther from the exhaust port and the lower surface of the cylinder head.

[0098] S3: Ensure that the simulated eddy current ratio is the same as the preset eddy current ratio.

[0099] After hydrogen is injected, the simulated swirl ratio inside the cylinder is obtained through simulation. The hydrogen injection components of the combustion system are adjusted according to the simulated swirl ratio until the simulated swirl ratio reaches the preset swirl ratio.

[0100] If the simulated eddy current ratio is lower than the preset eddy current ratio, at least one of conditions one and two can be performed. Condition one is to reduce the orifice diameter of the guide port of the hydrogen injection assembly of the combustion system, and condition two is to increase the angle α between the axis of the guide port and the axis of the guide sleeve of the hydrogen injection assembly.

[0101] S4: Ensure that the gas in the cylinder is mixed evenly.

[0102] Adjust the injection direction of the hydrogen injection assembly until the gas in the cylinder is evenly mixed.

[0103] If the mixture is uneven, adjust the injection direction of the guide port, increasing or decreasing the included angle β, until the mixture is uniform. Here, included angle β is the angle between the lines connecting the intake and exhaust ports and the lines connecting the guide port and exhaust port within the plane of the cylinder head. It should be noted that utilizing the tumble flow within the cylinder to provide driving force for the hydrogen allows it to flow faster within the combustion chamber, which is beneficial for increasing the vortex effect formed by the hydrogen.

[0104] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0105] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A combustion system for a hydrogen engine, characterized in that, include: A cylinder head (1) is arranged along the axis of the piston (6), and a combustion chamber (7) is formed between the cylinder head (1) and the piston (6); the cylinder head (1) is provided with at least two air inlets (11) and at least two exhaust ports (12), and both the air inlets (11) and the exhaust ports (12) are connected to the combustion chamber (7); The first air intake (21) and the second air intake (22) are connected to the air inlet (11), and the first air intake (21) and the second air intake (22) are channels for providing rolling flow of gas to the combustion chamber (7); Hydrogen injection assembly (4) is mounted on the cylinder head (1) and located between the intake port (11) and the exhaust port (12). The hydrogen injection assembly (4) is connected to the combustion chamber (7) and is used to inject hydrogen into the combustion chamber (7) in a direction toward the exhaust port (12) to form a vortex at the edge of the combustion chamber (7).

2. The combustion system of the hydrogen engine according to claim 1, characterized in that, The hydrogen injection assembly (4) includes a hydrogen injector (41) and a guide sleeve (42); The hydrogen injector (41) is mounted on the cylinder head (1), and the outlet end of the hydrogen injector (41) extends into the combustion chamber (7); The guide sleeve (42) is fitted onto the outlet end of the hydrogen injector (41), and the guide sleeve (42) has a guide opening (421) facing the exhaust port (12).

3. The combustion system of the hydrogen engine according to claim 2, characterized in that, The guide port (421) is located on the side of the guide sleeve (42) near the exhaust port (12) and is arranged radially along the guide sleeve (42).

4. The combustion system of the hydrogen engine according to claim 3, characterized in that, The cylinder head (1) is a flat-top cylinder head; in the plane of the cylinder head (1), the angle β between the projection of the axis of the guide port (421) onto the cylinder head (1) and the line connecting it to the horizontal direction is 30° to 60°. Wherein, the projection of the axis of the guide port (421) onto the cylinder head (1) is the projection of the axis of the guide port (421) onto the cylinder head (1) in a direction perpendicular to the cylinder head (1); the horizontal direction is the direction of the line connecting the adjacent air intake port (11) and the exhaust port (12) located on the cylinder head (1).

5. The combustion system of the hydrogen engine according to claim 2, characterized in that, The guide port (421) is located at the bottom of the guide sleeve (42) and is disposed near the exhaust port (12). The guide port (421) is a through hole that is inclined relative to the axial direction of the guide sleeve (42).

6. The combustion system of the hydrogen engine according to claim 5, characterized in that, The angle α between the axis of the guide port (421) and the axis of the guide sleeve (42) is 10° to 50°.

7. The combustion system of the hydrogen engine according to any one of claims 1 to 6, characterized in that, Both the first intake passage (21) and the second intake passage (22) are straight pipes, and the ends of the first intake passage (21) and the second intake passage (22) are bent and inserted into the corresponding intake ports (11). The ends of the first intake passage (21) and the second intake passage (22) are both facing the bottom of the combustion chamber (7), and the axis of the intake port (11) is perpendicular to the tangential direction of the edge of the cylinder head (1).

8. The combustion system of the hydrogen engine according to claim 7, characterized in that, The inner wall of the air intake (11) on the side near the exhaust port (12) has a first included angle A with the lower surface of the cylinder head (1); The inner wall of the air intake (11) on the side away from the exhaust port (12) has a second included angle B with the lower surface of the cylinder head (1), and the first included angle A is smaller than the second included angle B; The lower surface of the cylinder head (1) is the side of the cylinder head (1) opposite to the piston (6).

9. The combustion system of the hydrogen engine according to claim 8, characterized in that, The first included angle A is 30° to 40°; the second included angle B is 50° to 70°.

10. The combustion system of the hydrogen engine according to claim 7, characterized in that, It also includes an exhaust duct (3), which includes a first branch (31) and a second branch (32). One end of the first branch (31) and one end of the second branch (32) are respectively connected to an exhaust port (12), and the other end of the first branch (31) and the other end of the second branch (32) are connected as one unit.

11. A hydrogen engine, characterized in that, Includes a combustion system, said combustion system being a hydrogen engine as described in any one of claims 1 to 10.

12. A method for designing a combustion system for a hydrogen engine, used in the combustion system as described in any one of claims 1 to 10, characterized in that, include: Build a simulation model of the combustion system and set the preset swirl ratio and preset tumble ratio in the cylinder; Adjust the intake manifold structure until the simulated tumble ratio in the cylinder obtained from the simulation reaches the preset tumble ratio. After hydrogen is injected, the simulated vortex ratio in the cylinder is obtained through simulation. If the simulated vortex ratio is lower than the preset vortex ratio, at least one of conditions one and two can be performed until the simulated vortex ratio reaches the preset vortex ratio. Condition one is to reduce the orifice diameter of the guide port of the hydrogen injection assembly of the combustion system, and condition two is to increase the angle α between the axis of the guide port and the axis of the guide sleeve of the hydrogen injection assembly. Adjust the injection direction of the hydrogen injection assembly until the gas in the cylinder is evenly mixed.

13. The design method for the combustion system of a hydrogen engine according to claim 12, characterized in that, The construction of the combustion system simulation model includes: Build the initial simulation model; The initial simulation model is corrected, and the cylinder pressure, heat release rate and tumble ratio data obtained from the simulation calculation are compared with the experimental results. If the calibration error exceeds the preset range, the parameter settings and mesh of the simulation model are adjusted until the error meets the limit. Once the error meets the limit, the mesh settings and parameter settings in the simulation model are standardized to obtain the combustion system simulation model.

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