Cylinder head structure and hydrogen engine

Abstract

The present invention relates to the field of engine technology, and specifically discloses a cylinder head structure and a hydrogen engine, wherein the cylinder head structure includes a cylinder head body, a cylinder head bottom plate, an annular chamfered structure, and a plurality of slide groove structures. During the generation and propagation of a detonation pressure wave, since the annular chamfered structure is provided and surrounds the intake valve hole and the exhaust valve hole, the intensity of the detonation pressure wave can be weakened by increasing the volume of the cylinder head bottom plate when the detonation pressure wave moves radially along the intake valve hole; a plurality of slide groove structures are provided at intervals of the annular chamfered structure, so that when the detonation pressure wave moves in a circular motion along the annular chamfered structure, the intensity of the detonation pressure wave is gradually weakened by utilizing the plurality of slide groove structures. Under the combined action of the annular chamfered structure and the slide groove structure, the intensity of the detonation pressure wave is effectively reduced, and the occurrence of detonation is suppressed. Compared with other methods, the cylinder head structure of the present invention does not affect the design of the original cylinder head structure, has less impact on the performance of the hydrogen engine, and is low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a cylinder head structure and a hydrogen engine. Background Art

[0002] In the context of dual carbon emissions, hydrogen engines are developing rapidly, and knock is the primary issue limiting further improvements in their thermal efficiency. While the mechanism of hydrogen knock is not fully understood, recent research has shown that, unlike traditional gasoline and natural gas, hydrogen knock is mostly not caused by spontaneous combustion of the final mixture, but rather by a process of pressure wave oscillation and amplification. Existing methods for suppressing hydrogen engine knock still follow the principles of traditional engines, primarily focusing on controlling engine operating parameters, which can severely impact engine power and economy. Summary of the Invention

[0003] The purpose of the present invention is to provide a cylinder head structure and a hydrogen engine to solve the problem of hydrogen engine knock.

[0004] On the one hand, the present invention provides a cylinder head structure, which includes: a cylinder head body, a cylinder head base plate, which is arranged at the bottom of the cylinder head body, and the cylinder head base plate has two intake valve holes and two exhaust valve holes arranged at intervals; an annular chamfer structure, which is arranged on the cylinder head base plate and surrounds the intake valve holes and the exhaust valve holes; and a plurality of slide groove structures, wherein the plurality of slide groove structures are arranged at intervals on the annular chamfer structure.

[0005] As an optional technical solution for the cylinder head structure, in the depth direction of the intake valve hole, the length of the annular chamfered structure is a, 0.5mm≤a≤4mm, and in the radial direction of the intake valve hole, the length of the annular chamfered structure is b, 1mm≤b≤6mm.

[0006] As an optional technical solution for the cylinder head structure, in the cross section in the depth direction of the intake valve hole, the shape of the annular chamfered structure is triangular, rectangular or arc-shaped.

[0007] As an optional technical solution for the cylinder head structure, the angle between two adjacent slide groove structures is 16°-20°.

[0008] As an optional technical solution for the cylinder head structure, the sliding groove structure is a rectangular groove, and the extending direction of the rectangular groove is toward the center of the annular chamfered structure.

[0009] As an optional technical solution for the cylinder head structure, the length of the rectangular groove is d, 3mm≤d≤7mm, the width of the rectangular groove is c, 1.5mm≤c≤4mm, and the depth of the rectangular groove is h, 1mm≤h≤3mm.

[0010] As an optional technical solution for the cylinder head structure, in the radial cross section of the intake valve hole, the shape of the slide groove structure is a parallelogram or an arc.

[0011] As an optional technical solution for the cylinder head structure, the number of the slide groove structures is 6-30.

[0012] On the other hand, the present invention provides a hydrogen engine, comprising an engine cylinder and a cylinder head structure according to any of the above schemes, wherein the cylinder head structure can be connected to the engine cylinder.

[0013] As an optional technical solution for the hydrogen engine, the outer diameter of the annular chamfered structure of the cylinder head structure is equal to the diameter of the engine cylinder.

[0014] The beneficial effects of the present invention are:

[0015] The present invention provides a cylinder head structure, which includes a cylinder head body, a cylinder head base plate, an annular chamfered structure, and multiple slide groove structures. With the cylinder head structure of the present invention, when a detonation pressure wave is generated and propagated, the annular chamfered structure is provided, surrounding the intake and exhaust valve holes. This allows the volume of the cylinder head base plate to be increased, thereby weakening the intensity of the detonation pressure wave as the detonation pressure wave moves radially along the intake valve hole. At the same time, multiple slide groove structures are provided at intervals between the annular chamfered structure. As the detonation pressure wave moves in a circular motion along the annular chamfered structure, the multiple slide groove structures are utilized to gradually weaken the intensity of the detonation pressure wave. The combined effects of the annular chamfered structure and the slide groove structure effectively reduce the intensity of the detonation pressure wave, suppressing the occurrence of detonation. Compared to other methods, the cylinder head structure of the present invention does not affect the design of the original cylinder head structure, has less impact on hydrogen engine performance, and is inexpensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the cylinder head structure in the first embodiment of the present invention;

[0017] Figure 2 A cross-sectional view of a cylinder head structure according to an embodiment of the present invention;

[0018] Figure 3 for Figure 2 A magnified view of the middle annular chamfer structure;

[0019] Figure 4 for Figure 1 Enlarged view of the middle chute structure;

[0020] Figure 5 A cross-sectional view of a cylinder head structure according to a second embodiment of the present invention;

[0021] Figure 6A cross-sectional view of a cylinder head structure in a third embodiment of the present invention;

[0022] Figure 7 Schematic diagram of the cylinder head structure in the fourth embodiment of the present invention;

[0023] Figure 8 Schematic diagram of the cylinder head structure in the fifth embodiment of the present invention;

[0024] Figure 9 Schematic diagram comparing the cylinder pressure between the cylinder head structure in the embodiment of the present invention and the original cylinder head structure.

[0025] In the picture:

[0026] 1. Cylinder head body;

[0027] 2. Cylinder head base plate; 21. Intake valve hole; 22. Exhaust valve hole;

[0028] 3. Annular chamfer structure;

[0029] 4. Chute structure;

[0030] 5. Spark plug hole. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0035] like Figures 1 to 9 As shown, this embodiment provides a cylinder head structure, which includes a cylinder head body 1, a cylinder head base plate 2, an annular chamfered structure 3, and multiple slide groove structures 4. The cylinder head base plate 2 is disposed at the bottom of the cylinder head body 1 and has two intake valve holes 21 and two exhaust valve holes 22 spaced apart. The annular chamfered structure 3 is disposed on the cylinder head base plate 2 and surrounds the intake valve holes 21 and the exhaust valve holes 22. The multiple slide groove structures 4 are spaced apart on the annular chamfered structure 3.

[0036] With the cylinder head structure of the present invention, when the detonation pressure wave is generated and propagated, the annular chamfered structure 3 is provided, and surrounds the intake valve hole 21 and the exhaust valve hole 22. This can reduce the intensity of the detonation pressure wave by increasing the volume of the cylinder head bottom plate 2 when the detonation pressure wave moves radially along the intake valve hole 21. At the same time, multiple slide groove structures 4 are provided at intervals on the annular chamfered structure 3. When the detonation pressure wave moves in a circular motion along the annular chamfered structure 3, the multiple slide groove structures 4 are used to gradually reduce the intensity of the detonation pressure wave. Under the combined action of the annular chamfered structure 3 and the slide groove structure 4, the intensity of the detonation pressure wave is effectively reduced, and the occurrence of detonation is suppressed. Compared with other methods, the cylinder head structure of the present invention does not affect the design of the original cylinder head structure, has less impact on the performance of the hydrogen engine, and is low in cost.

[0037] It should be noted that the cylinder head structure of the present invention interferes with the detonation pressure wave during its generation and propagation by modifying the original cylinder head structure.

[0038] According to the latest research, a detonation pressure wave is generated at the flame front during flame development. It then moves radially outward along the cylinder head base plate 2 to the cylinder liner surface. After contacting the cylinder liner, it then moves in a circular motion around the cylinder liner. The anti-detonation structure of the present invention comprises two structures. The first is an annular chamfered structure 3, distributed on the cylinder head base plate 2. This structure increases the volume and weakens the detonation pressure wave's strength during radial movement. The second structure is a chute structure, evenly distributed on the annular chamfered structure 3, which gradually weakens the detonation pressure wave's strength during its circular motion. These two structures, combined together, reduce the intensity of the detonation pressure wave and suppress the occurrence of detonation.

[0039] Optionally, the cylinder head base plate 2 has a spark plug hole 5 , which is located at the center of the cylinder head base plate 2 , and the two intake valve holes 21 and the two exhaust valve holes 22 all surround the spark plug hole 5 .

[0040] like Figure 1 and Figure 3 As shown, in the depth direction of the intake valve hole 21, the length of the annular chamfered structure 3 is a, 0.5mm≤a≤4mm. In this embodiment, limiting the length a of the annular chamfered structure 3 within the aforementioned range can further increase the volume of the cylinder head base plate 2, thereby weakening the intensity of the detonation pressure wave. The length a of the annular chamfered structure 3 can be adjusted according to actual needs, and can be selected from 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, or 4mm. Furthermore, in the radial direction of the intake valve hole 21, the length of the annular chamfered structure 3 is b, 1mm≤b≤6mm. This configuration, limiting the length b of the annular chamfered structure 3 within the aforementioned range, combined with the length a of the annular chamfered structure 3, can further increase the volume of the cylinder head base plate 2, thereby weakening the intensity of the detonation pressure wave. Among them, the length b of the annular chamfered structure 3 can be adjusted according to actual needs. The length b of the annular chamfered structure 3 can be selected as 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm or 6mm, etc.

[0041] like Figure 1 and, Figure 2 and Figure 3 As shown, on the cross section in the depth direction of the intake valve hole 21, the shape of the annular chamfered structure 3 is triangular. This arrangement can effectively increase the volume of the cylinder head base plate 2, thereby weakening the intensity of the detonation pressure wave.

[0042] Or, as Figure 1 and Figure 5 As shown, on the cross section in the depth direction of the intake valve hole 21, the shape of the annular chamfered structure 3 is rectangular, which can also effectively increase the volume of the cylinder head base plate 2 and thus weaken the intensity of the detonation pressure wave.

[0043] Or, as Figure 1 and Figure 6 As shown, on the cross section in the depth direction of the intake valve hole 21, the shape of the annular chamfered structure 3 is arc-shaped. Such an arrangement can also effectively increase the volume of the cylinder head base plate 2, thereby weakening the intensity of the detonation pressure wave.

[0044] Optionally, in the cross section of the intake valve hole 21 in the depth direction, the shape of the annular chamfered structure 3 may be a polygon.

[0045] In this embodiment, the angle between two adjacent chute structures 4 is 16°-20°.

[0046] This can avoid the situation where the distance between two adjacent chute structures 4 is too large, thereby poorly weakening the intensity of the detonation pressure wave. A suitable angle between two adjacent chute structures 4 can be selected based on actual needs. Specifically, the angle between two adjacent chute structures 4 can be 16°, 17°, 18°, 19°, or 20°. Preferably, in this embodiment, the angle between two adjacent chute structures 4 is 18°.

[0047] In some embodiments, as Figure 1 As shown, the chute structure 4 is a rectangular groove, the extension direction of the rectangular groove is toward the center of the annular chamfered structure 3, the length of the rectangular groove is d, 3mm≤d≤7mm, the width of the rectangular groove is c, 1.5mm≤c≤4mm, and the depth of the rectangular groove is h, 1mm≤h≤3mm. With this arrangement, a suitable length can be selected according to the actual needs of the site, wherein the length d of the rectangular groove can be selected as 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm or 7mm, etc. The width c of the rectangular groove can be selected as 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm or 4mm, etc. The depth h of the rectangular groove can be selected as 1mm, 1.5mm, 2mm, 2.5mm or 3mm, etc.

[0048] In some embodiments, as Figure 7 As shown, on the radial cross section of the intake valve hole 21, the shape of the slide groove structure 4 is a parallelogram. This arrangement can also gradually weaken the strength of the detonation pressure wave when it moves in a circular motion, effectively reducing the strength of the detonation pressure wave and suppressing the occurrence of detonation.

[0049] or, as Figure 8 As shown, the shape of the chute structure 4 is an arc in the radial cross section of the intake valve hole 21. This arrangement can also gradually weaken the intensity of the detonation pressure wave during its circular motion, effectively reducing the intensity of the detonation pressure wave and suppressing the occurrence of detonation.

[0050] In some embodiments, the number of the chute structures 4 is 6 to 30. The number of the chute structures 4 can be selected according to actual needs. Specifically, the number of the chute structures 4 can be selected as 6, 10, 15, 20, 25 or 30.

[0051] This embodiment also provides a hydrogen engine, comprising an engine cylinder and the cylinder head structure of the above-described embodiment, which is connectable to the engine cylinder. In the hydrogen engine of the present invention, when a detonation pressure wave is generated and propagated, the annular chamfered structure 3 is provided, surrounding the intake valve hole 21 and the exhaust valve hole 22. This allows the volume of the cylinder head base plate 2 to be increased as the detonation pressure wave moves radially along the intake valve hole 21, thereby weakening the intensity of the detonation pressure wave. Furthermore, multiple chute structures 4 are spaced apart within the annular chamfered structure 3. As the detonation pressure wave moves in a circular motion along the annular chamfered structure 3, the multiple chute structures 4 gradually weaken the intensity of the detonation pressure wave. The combined action of the annular chamfered structure 3 and the chute structure 4 effectively reduces the intensity of the detonation pressure wave, suppressing the occurrence of detonation. Compared to other methods, the hydrogen engine of the present invention does not affect the design of the original cylinder head structure, has a minimal impact on hydrogen engine performance, and is inexpensive.

[0052] It should be noted that the present invention mentions two types of knock suppression structures - chamfer structure and slide groove structure. Cylinder heads using only one of these structures are also within the scope of protection of this patent.

[0053] The main purpose of the annular chamfer structure of this patent is to utilize the expansion of space to reduce the intensity of pressure waves. Therefore, other similar structures are also within the scope of protection of this patent, such as rectangular ring groove structures or arc-shaped ring groove structures; the long side of the slide groove structure of this patent can be a straight line that is not parallel to the diameter direction of the piston top surface, or it can be an arc shape; the slide groove structure of this patent does not require the size and shape of each slide groove to be consistent, and the intervals between adjacent slide groove structures can also be different, that is, the array slide groove structure with different sizes and shapes and uneven circumferential distribution is also within the scope of protection of this patent.

[0054] Specifically, the outer diameter of the annular chamfered structure 3 of the cylinder head structure is equal to the diameter of the engine cylinder. This allows the detonation pressure wave to be generated at the flame front during flame development, then initially move radially outward along the cylinder head base plate 2 to the cylinder liner surface. After contacting it, it then moves in a circular motion around the cylinder liner.

[0055] After using the patent of this invention, the compression ratio of the hydrogen engine may be reduced by about 0.05-0.1 depending on the actual situation. Although it will slightly affect the thermal efficiency of the hydrogen engine, after achieving the corresponding anti-knock effect, the ignition angle of the hydrogen engine can be advanced, and the benefits obtained are far higher than the loss of thermal efficiency; at the same time, the hydrogen engine can also use the method of redesigning the piston pit or reducing the thickness of the cylinder gasket to replenish the compression ratio, or even increase the compression ratio according to the actual knock situation to obtain greater thermal efficiency benefits.

[0056] The following uses a commercial vehicle hydrogen engine as an example to specifically illustrate the implementation and effects of the present invention.

[0057] When the anti-knock structure of the present invention is applied to the hydrogen engine, the dimensions of the annular chamfer structure are a = 2mm and b = 4mm, distributed around the lower end surface of the cylinder head; the number of the chute structures is 20, evenly distributed on the annular chamfer structure, the angle between two adjacent chute structures is 18°, and the rectangular groove has a width c = 2mm, a length d = 6mm, and a depth h of 2mm.

[0058] The other configurations of the hydrogen engine remain unchanged, and the test conditions remain unchanged. After using this patent, the engine's knock condition has been significantly improved. Figure 9 As shown, the horizontal axis is the crankshaft angle and the vertical axis is the cylinder pressure. It can be seen that when using the original cylinder head structure, the engine has obvious knock, which is manifested as obvious fluctuations in the cylinder pressure; after using the cylinder head structure of this patent, this pressure fluctuation obviously disappears and the knock is effectively suppressed.

[0059] The design ideas of this patent are as follows:

[0060] A typical cylinder head structure has four valve holes and a spark plug hole arranged on its lower end face. The intake valve hole is typically larger than the exhaust valve hole, and the spark plug hole is located in the center. While the lower end face of a conventional cylinder head is smooth, the patented knock suppression structure incorporates an annular chamfer and a sliding groove, primarily located around the outer ring of the valve holes and beyond.

[0061] like Figure 3 As shown, in some embodiments, the annular chamfered structure is triangular, the chamfer dimension a is in the range of 0.5-4 mm, b is in the range of 1-6 mm, and the maximum diameter of the chamfer is equal to the cylinder diameter of the engine cylinder.

[0062] The chute structures of this patent are within the range of 6-30 and need to be evenly distributed within the annular chamfered structure, with the angles between each chute structure being equal. The top view of the chute structure is rectangular, with its long side parallel to the piston diameter and its wide side perpendicular to the piston diameter. The width c ranges from 1.5-4mm, and the length d ranges from 3-7mm. The depth h of the chute structure in the front view ranges from 1-3mm. The diameter of its outermost circle is equal to the cylinder diameter.

[0063] The cylinder head structure of the present invention can suppress hydrogen engine knock and achieve the following benefits:

[0064] 1. The cylinder head structure of the present invention can effectively suppress knock. According to test results, it can reduce the knock index by more than 40%.

[0065] 2. In view of the different knock mechanisms of hydrogen engines and conventional gasoline or natural gas engines, the cylinder head structure of the present invention can suppress the generation of the knock pressure wave in the early stage and continuously weaken its strength during the subsequent propagation process. It is a knock suppression structure designed specifically for the hydrogen knock mechanism;

[0066] 3. The cylinder head structure of the present invention does not require changes to other engine structures to match it, and the overall modification of the engine is relatively small;

[0067] 4. The cylinder head structure of the present invention can suppress engine knock without substantially affecting engine performance, thus avoiding the negative effects of conventional knock suppression methods.

[0068] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A cylinder head structure, characterized in that: include: Cylinder head body (1), A cylinder head base plate (2) is arranged at the bottom of the cylinder head body (1), and the cylinder head base plate (2) has two intake valve holes (21) and two exhaust valve holes (22) arranged at intervals; An annular chamfered structure (3) is provided on the cylinder head bottom plate (2) and surrounds the intake valve hole (21) and the exhaust valve hole (22); A plurality of slide groove structures (4), wherein the plurality of slide groove structures (4) are arranged at intervals on the annular chamfered structure (3).

2. The cylinder head structure according to claim 1, characterized in that: In the depth direction of the intake valve hole (21), the length of the annular chamfered structure (3) is a, 0.5mm≤a≤4mm, and in the radial direction of the intake valve hole (21), the length of the annular chamfered structure (3) is b, 1mm≤b≤6mm.

3. The cylinder head structure according to claim 1, characterized in that: On a cross section in the depth direction of the intake valve hole (21), the shape of the annular chamfered structure (3) is triangular, rectangular or arc-shaped.

4. The cylinder head structure according to claim 1, characterized in that: The angle between two adjacent chute structures (4) is 16°-20°.

5. The cylinder head structure according to claim 1, characterized in that: The sliding groove structure (4) is a rectangular groove, and the extending direction of the rectangular groove is toward the center of the annular chamfered structure (3).

6. The cylinder head structure according to claim 5, characterized in that: The length of the rectangular groove is d, 3mm≤d≤7mm, the width of the rectangular groove is c, 1.5mm≤c≤4mm, and the depth of the rectangular groove is h, 1mm≤h≤3mm.

7. The cylinder head structure according to claim 1, characterized in that: On the radial cross section of the intake valve hole (21), the shape of the slide groove structure (4) is a parallelogram or an arc.

8. The cylinder head structure according to claim 1, characterized in that: The number of the chute structures (4) is 6 to 30.

9. A hydrogen engine, characterized in that: It comprises an engine cylinder and the cylinder head structure according to any one of claims 1 to 8, wherein the cylinder head structure can be connected to the engine cylinder.

10. The hydrogen engine according to claim 9, characterized in that: The outer diameter of the annular chamfered structure (3) of the cylinder head structure is equal to the diameter of the engine cylinder.

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