Compact gasoline engine cylinder head structure

Abstract

The application discloses a compact gasoline engine cylinder cover structure, which comprises a first cylinder cover assembly, a second cylinder cover assembly, an oil flow channel assembly and a working space, wherein the first cylinder cover assembly comprises a front cylinder cover and an oil return hole arranged at one end of the front cylinder cover; the second cylinder cover assembly is detachably matched with one end of the first cylinder cover assembly, and the second cylinder cover assembly and the first cylinder cover assembly have a working space in common inside the second cylinder cover assembly and the first cylinder cover assembly. The compact gasoline engine cylinder cover structure has the oil return function arranged on the front cylinder cover, can guarantee the flow direction of the air passage, is designed to utilize the shape of oil flow, can achieve the effect of flow gathering and speed increasing, and simultaneously realizes the PCV function by establishing the passage by utilizing the oil cavity wall of the cylinder cover itself, reduces the weight of the cylinder cover, and simultaneously realizes the purpose of light weight by the compact design of the oil return hole. Throttling holes are added in the main oil channel, the throttling holes are connected with the exhaust oil supply channel, and the oil pressure loss is reduced.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and more particularly to a compact gasoline engine cylinder head structure. Background Technology

[0002] The cylinder head and piston together form the combustion chamber. During engine operation, the cylinder head combustion chamber is repeatedly subjected to strong pressure shocks and temperature changes, making the working environment quite harsh. Under these conditions, a well-designed cylinder head will determine the cylinder head's pressure bearing capacity and cooling temperature control capabilities. Furthermore, the design of the cylinder head's intake and exhaust port shapes, combustion chamber shapes, and other features also have a significant impact on engine performance.

[0003] The 1.5L displacement engine is widely used in family cars, but the cylinder head of this displacement engine has large parts and a non-compact structure, which means that the existing oil return hole design occupies a large amount of internal space in the cylinder head. It also results in poor combustion and gas flow performance, complicated processing and casting, high cost, and large size and weight of the parts. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the current compact gasoline engine cylinder head structure, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to provide a compact gasoline engine cylinder head structure, which aims to save layout space and improve oil return efficiency while reducing the total weight of the cylinder head, lowering costs and reducing oil pressure loss.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a first cylinder head assembly, including a front cylinder head, an oil return hole disposed at one end of the front cylinder head, and a PCV channel disposed inside the front cylinder head; a second cylinder head assembly, detachably fitted to one end of the first cylinder head assembly, and having a shared working space with the interior of the first cylinder head assembly; and an oil flow channel assembly, disposed inside the first cylinder head assembly and the second cylinder head assembly, and communicating with the working space.

[0008] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, the first cylinder head assembly further includes an exhaust-side oil return port and an intake-side port respectively disposed at the outer end of the front cylinder head; the PCV channel is connected to an air passage provided in the working space.

[0009] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, the second cylinder head assembly includes a rear cylinder head that is connected to one side of the front cylinder head, and a cam groove that is jointly formed by the front cylinder head and the rear cylinder head.

[0010] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, the working space is composed of an oil chamber, a valve guide bottom hole, an air passage, a combustion chamber and a return oil guide chamber, and the oil chamber is connected to the return oil guide chamber.

[0011] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, wherein: the bottom hole of the valve guide connects the air passage and the oil chamber, the oil return hole is hollow, and the air passage is connected to the PCV channel.

[0012] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, the PCV channel includes a main through hole, an upper through hole, a connecting hole, and an oblique hole; the main through hole is opened on one side of the front cylinder head and connects the upper through hole, the connecting hole, and the oblique hole; one end of the upper through hole away from the main through hole extends to the other side of the front cylinder head; one end of the connecting hole extends to the outside of the front cylinder head; and the end of the oblique hole away from the main through hole connects to the air passage.

[0013] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, the oil flow channel assembly includes an upper oil port, a main oil passage, an intake hydraulic tappet, and an exhaust hydraulic tappet; the main oil passage and the intake hydraulic tappet are both connected to the outer surface of the upper oil port, and the intake hydraulic tappet and the exhaust hydraulic tappet are respectively connected to both ends of the main oil passage.

[0014] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, wherein: the intake hydraulic tappet is connected to the upper oil port through the intake oil supply passage, and the exhaust hydraulic tappet is connected to the main oil passage through the throttle hole.

[0015] In a preferred embodiment of the compact gasoline engine cylinder head structure described in this invention, the throttle orifice and the oil inlet are respectively connected to both ends of the main oil passage.

[0016] As a preferred embodiment of the compact gasoline engine cylinder head structure of the present invention, the oil flow channel assembly further includes an exhaust oil supply channel, which is connected to one end of the main oil channel and is also connected to the throttle orifice.

[0017] The beneficial effects of this invention are as follows: The oil return function provided on the front cylinder head can ensure the airflow direction while being designed to utilize the shape of oil flow, thereby achieving the effect of flow aggregation and acceleration. At the same time, through the oil flow channel assembly, the channel is established by utilizing the oil cavity wall of the cylinder head itself, realizing the PCV function while reducing the weight of the cylinder head. In addition, the oil return hole is designed to be compact, achieving the purpose of weight reduction. A throttle hole is added to the main oil passage, connecting the throttle hole to the exhaust oil supply passage, reducing oil pressure loss. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. 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. Wherein:

[0019] Figure 1 This is a schematic diagram of the overall structure of the compact gasoline engine cylinder head structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the connection structure between the front and rear cylinder heads of the compact gasoline engine cylinder head structure of the present invention.

[0021] Figure 3 This is a side view of the connection between the front and rear cylinder heads of the compact gasoline engine cylinder head structure of the present invention.

[0022] Figure 4 This is a schematic diagram of the cylinder head oil flow channel assembly structure of the compact gasoline engine cylinder head structure of the present invention.

[0023] Figure 5 This is a cross-sectional view of the oil return guide cavity of the compact gasoline engine cylinder head structure of the present invention, which adopts a flow-converging design.

[0024] Figure 6 This is a cross-sectional view of the air passage and main through hole of the compact gasoline engine cylinder head structure of the present invention, which are connected by an oblique hole.

[0025] Figure 7 This is a cross-sectional view of the connection between the upper through hole and the main through hole in the compact gasoline engine cylinder head structure of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0030] Example 1

[0031] Reference Figures 1-4 The first embodiment of the present invention provides a compact gasoline engine cylinder head structure, which includes a first cylinder head assembly 100, a second cylinder head assembly 200, an oil flow passage assembly 300, and a working space G.

[0032] The first cylinder head assembly 100 includes a front cylinder head 101, an oil return hole 102 disposed at one end of the front cylinder head 101, and a PCV channel 105 disposed inside the front cylinder head 101; the second cylinder head assembly 200 is detachably fitted to one end of the first cylinder head assembly 100, and shares a working space G with the first cylinder head assembly 100; and the oil flow passage assembly 300 is disposed inside the first cylinder head assembly 100 and the second cylinder head assembly 200, and communicates with the working space G.

[0033] During use, the first cylinder head assembly 100 and the second cylinder head assembly 200 are combined to form a gasoline engine cylinder head, which can be disassembled and installed for easy maintenance. The internal oil flow channel assembly 300 is located in the first cylinder head assembly 100 and the second cylinder head assembly 200 to reduce the risk of air-fuel mixture leakage and improve emissions. At the same time, the oil flow channel assembly 300 reduces the weight of the cylinder head and reduces costs. The whole system operates through the working space G.

[0034] Furthermore, the "front" in the front cylinder head 101 of the present invention is not limited to the front side, but only corresponds to... Figure 2The working space G formed by the combination of the first cylinder head assembly 100 and the second cylinder head assembly 200 is used to ensure that the temperature generated by the gasoline engine cylinder head is distributed as evenly as possible during operation, so as to prevent serious thermal cracking of the gasoline engine cylinder head components.

[0035] Furthermore, the first cylinder head assembly 100 and the second cylinder head assembly 200 are not limited to being cast from gray cast iron or alloy cast iron; the first cylinder head assembly 100 and the second cylinder head assembly 200 can be manufactured using lighter aluminum alloy materials to reduce weight.

[0036] Example 2

[0037] Reference Figures 1-7 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that: the first cylinder head assembly 100 further includes an exhaust-side oil return port 103 and an intake-side port 104 respectively disposed at the outer end of the front cylinder head 101; the PCV passage 105 connects to the air passage G3 provided in the working space G; the second cylinder head assembly 200 includes a rear cylinder head 201 that is connected to one side of the front cylinder head 101, and a cam groove 202 jointly formed by the front cylinder head 101 and the rear cylinder head 201.

[0038] Compared to Embodiment 1, the oil return function of the first cylinder head assembly 100 is designed in three parts during use. The first part is arranged in the oil return hole of the intake side port 104, which is integrated with the intake side bolt hole of the cylinder head. This allows oil to flow from the exhaust side oil return port 103 to the intake side port 104 during the oil return process, thereby effectively saving arrangement space and meeting functional requirements.

[0039] Furthermore, the second part is arranged at the rear end of the exhaust side oil return port 103, and is composed of a large oil return hole with a diameter that can be set to 25mm, so as to return oil while effectively reducing the weight of the cylinder head.

[0040] Furthermore, the third part adopts a hollowed-out design for the oil return hole 102 and a beveled flow-gathering structure design to effectively enhance the oil return effect.

[0041] By designing three parts to improve oil return efficiency, the overall weight of the cylinder head is reduced, thus lowering costs. This design utilizes the flow of oil while ensuring the air passage direction, achieving the effect of flow aggregation and acceleration.

[0042] All of these designs utilize the internal space of the cylinder head to create a usable oil return line within these compact and multifunctional features.

[0043] Meanwhile, the integrated traveling tray on the exhaust side of the front cylinder head 101 consists of multiple locating pin holes and tension bolts. It not only meets the dimensional requirements of the exhaust side's functional characteristics but also accommodates two of the locating pins. During processing, the front cylinder head 101 and the traveling tray remain together as they are processed on different machine tools. Each processing operation only requires positioning of the traveling tray and the machine tool table, allowing the front cylinder head 101 to always travel on the tray during processing. Positioning with the machine tool via the traveling tray enhances processing flexibility. While meeting the functional requirements of the exhaust side, the integrated traveling tray on the exhaust side of the front cylinder head 101 provides installation and positioning functions until processing is completely finished. Only then will the front cylinder head 101 and the traveling tray separate, enabling co-production with other cylinder heads. This improves flexibility while eliminating the cost of modifying the fixtures for gasoline engine cylinder head processing equipment.

[0044] The remaining structure is the same as that in Example 1.

[0045] Example 3

[0046] Reference Figures 5-7 This is the third embodiment of the present invention. The difference between this embodiment and the second embodiment is that the working space G is composed of an oil chamber G1, a valve guide bottom hole G2, an air passage G3, a combustion chamber G4, and a return oil guide cavity G5, and the oil chamber G1 is connected to the return oil guide cavity G5; the valve guide bottom hole G2 connects the air passage G3 and the oil chamber G1, and the return oil hole 102 is hollow, and the air passage G3 is connected to the PCV channel 105.

[0047] Compared to Example 2, during use, the working space G operates while the vehicle is running. The entire system can work smoothly through the connected oil chamber G1, valve guide bottom hole G2, air passage G3, combustion chamber G4, and return oil guide chamber G5. The sealed combustion space is used to withstand high temperature and high pressure combustion gases.

[0048] Furthermore, the working space G can make the temperature field as uniform as possible, effectively reducing thermal stress and thus avoiding thermal cracking. In the oil cavity G1 set by the present invention, the transmission uniformity is improved by the symmetrical valve guide bottom hole G2.

[0049] Furthermore, the oil return hole 102 is designed with a hollowed-out shape. Both the oil return guide cavity G5 and the oil return hole 102 are designed with a flow-gathering structure. Through the design of both, the oil return effect can be enhanced by their shape during the oil return process, improving the oil return efficiency while ensuring the airflow direction. The oil return effect is increased by the gas. This design can also utilize the oil flow to achieve the effect of flow gathering and acceleration. The oil return hole 102 can also adopt a symmetrical design.

[0050] The remaining structure is the same as that in Example 2.

[0051] Example 4

[0052] Reference Figures 1-3 and Figures 4-7 This is the fourth embodiment of the present invention. The difference between this embodiment and the third embodiment is that the PCV channel 105 includes a main through hole 105a, an upper through hole 105b, a connecting hole 105c, and an oblique hole 105d. The main through hole 105a is opened on one side of the front cylinder head 101 and connects the upper through hole 105b, the connecting hole 105c, and the oblique hole 105d. One end of the upper through hole 105b away from the main through hole 105a extends to the other side of the front cylinder head 101. One end of the connecting hole 105c extends to the outside of the front cylinder head 101, and the end of the oblique hole 105d away from the main through hole 105a is connected to the air passage G3.

[0053] Compared to Example 3, in the operation of this engine, oil is pumped up from the bottom of the engine to lubricate moving parts such as the camshaft and valves. The lubricated oil falls into the oil chamber G1. After entering the oil chamber G1, the oil flows downward towards the return oil guide chamber G5 and towards the bottom of the engine. On the other side, it flows from the air passage G3 to the combustion chamber G4 for operation.

[0054] Furthermore, during the oil circulation process, the oil returns through the oil return hole 102, the exhaust side oil return port 103, and the intake side port 104. The PCV channel 105, formed by the main through hole 105a, the upper through hole 105b, the connecting hole 105c, and the inclined hole 105d, functions independently to create a crankcase forced ventilation effect. During the ventilation process, the oil discharged from the inclined hole 105d increases the efficiency of the return oil flowing from the intake passage G3 to the combustion chamber G4. The inclined hole 105d can be set to 46° to 48°. When the air-fuel mixture enters from the cover, since the inclined hole 105d is completely connected to the main through hole 105a, it enters the intake passage through the inclined hole 105d, which can effectively reduce the risk of air-fuel mixture leakage and improve emissions, allowing fresh air to flow evenly to each cylinder, thereby ensuring smooth operation of the four cylinders of the engine.

[0055] Furthermore, the main through hole 105a is relatively long and adopts a single-sided blind hole design, reducing the need for steel ball sealing measures, thereby reducing the scope and cost of manufacturing equipment modification. During the leak test, it can be connected with the intake duct, combustion chamber, and exhaust duct to form a communication mechanism for joint leak testing, reducing the functional investment in leak testing equipment and lowering costs.

[0056] The overall PCV channel 105 is integrated into the intake side port 104 at the outer end of the front cylinder head 101, and the outlet is at the top of the exhaust side oil return port 103. It effectively utilizes the oil chamber wall itself to establish the channel, realizes the PCV function, and reduces the weight of the cylinder head, thus achieving the goal of lightweighting.

[0057] The remaining structure is the same as that in Example 3.

[0058] Example 5

[0059] Reference Figures 1-4 This is the fifth embodiment of the present invention. The difference between this embodiment and the fourth embodiment is that the oil flow channel assembly 300 includes an upper oil port 301, a main oil passage 303, an intake hydraulic tappet 304, and an exhaust hydraulic tappet 306. The main oil passage 303 and the intake hydraulic tappet 304 are both connected to the outer surface of the upper oil port 301, and the intake hydraulic tappet 304 and the exhaust hydraulic tappet 306 are respectively connected to both ends of the main oil passage 303.

[0060] The intake hydraulic tappet 304 is connected to the upper oil port 301 through the intake oil supply passage 302, and the exhaust hydraulic tappet 306 is connected to the main oil passage 303 through the throttle hole 305. The throttle hole 305 and the upper oil port 301 are respectively connected to the two ends of the main oil passage 303. The oil flow passage assembly 300 also includes an exhaust oil supply passage 307, which is connected to one end of the main oil passage 303 and is also connected to the throttle hole 305.

[0061] Compared to Example 4, during use, oil is supplied through the oil inlet 301 and enters one of the intake hydraulic tappets 304 through the intake oil supply channel 302. At the same time, oil is supplied through the oil inlet 301 and also enters the main oil channel 303. Then, it is diverted to the throttle orifice 305 and the exhaust oil supply channel 307. The oil in the throttle orifice 305 can enter another intake hydraulic tappet 304.

[0062] Furthermore, a series of holes forming the function of the oil flow channel assembly 300 are constructed through the oil inlet 301, intake oil supply channel 302, main oil channel 303, intake hydraulic tappet 304, throttle orifice 305, exhaust hydraulic tappet 306, and exhaust oil supply channel 307, thereby reducing the weight of the cylinder head and lowering costs. The oil cavity wall of the cylinder head itself is used to establish the channel, realizing the oil circuit function while reducing the weight of the cylinder head and achieving the goal of lightweighting.

[0063] Furthermore, the width of the throttle orifice 305 should be smaller than the width of the upper oil port 301, the intake oil supply passage 302, the main oil passage 303, the intake hydraulic tappet 304, and the exhaust oil supply passage 307 to reduce oil pressure loss.

[0064] Furthermore, through the compact design of the first cylinder head assembly 100, the second cylinder head assembly 200, and the oil flow channel assembly 300, the oil enters from the upper through hole 305a and is divided into two intake hydraulic tappet branches 304. One intake hydraulic tappet branch 304 supplies oil to the exhaust hydraulic tappet and the camshaft diameter slide, while the other intake hydraulic tappet branch 304 supplies oil to the intake hydraulic tappet and the camshaft diameter slide. In other words, one branch supplies oil to the hydraulic tappet, journal lubrication, and vacuum pump respectively, while the other branch supplies oil to the VVT ​​in the camshaft. By adding the design of the throttle orifice 305, the oil pressure loss is effectively reduced. The VVT ​​oil supply channel is designed at the second camshaft diameter, without occupying the rolling bearing design of the first camshaft diameter.

[0065] Furthermore, the integrated hydraulic tappet design offers a longer lifespan and lower operating noise compared to traditional mechanical tappets.

[0066] The remaining structure is the same as that in Example 4.

[0067] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0068] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the currently considered best mode for carrying out the invention, or those features that are not relevant to implementing the invention) may be omitted.

[0069] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A compact gasoline engine cylinder head structure, characterized in that: include, The first cylinder head assembly (100) includes a front cylinder head (101), an oil return hole (102) disposed at one end of the front cylinder head (101), and a PCV channel (105) disposed inside the front cylinder head (101). The second cylinder head assembly (200) is detachably fitted to one end of the first cylinder head assembly (100), and shares a working space (G) with the interior of the first cylinder head assembly (100); and, An oil flow channel assembly (300) is disposed inside the first cylinder head assembly (100) and the second cylinder head assembly (200) and communicates with the working space (G); The second cylinder head assembly (200) includes a rear cylinder head (201) that is connected to one side of the front cylinder head (101), and a cam groove (202) that is opened together by the front cylinder head (101) and the rear cylinder head (201). The PCV channel (105) includes a main through hole (105a), an upper through hole (105b), a connecting hole (105c), and an oblique hole (105d). The PCV channel (105) is connected to the air passage (G3) provided in the workspace (G). The main through hole (105a) is opened on one side of the front cylinder head (101) and connects the upper through hole (105b), the connecting hole (105c) and the oblique hole (105d). The upper through hole (105b) extends away from the main through hole (105a) to the other side of the front cylinder head (101). One end of the connecting hole (105c) extends to the outside of the front cylinder head (101), and the oblique hole (105d) connects away from the main through hole (105a) to the air passage (G3). The oil flow channel assembly (300) includes an oil inlet (301), a main oil passage (303), an intake hydraulic tappet (304), and an exhaust hydraulic tappet (306). The main oil passage (303) and the intake hydraulic tappet (304) are both connected to the outer surface of the upper oil port (301), and the intake hydraulic tappet (304) and the exhaust hydraulic tappet (306) are respectively connected to both ends of the main oil passage (303); The intake hydraulic tappet (304) is connected to the upper oil port (301) through the intake oil supply channel (302), and the exhaust hydraulic tappet (306) is connected to the main oil passage (303) through the throttle hole (305). The throttle orifice (305) and the upper oil port (301) are respectively connected to both ends of the main oil passage (303); The oil flow path assembly (300) also includes an exhaust oil supply passage (307), which is connected to one end of the main oil passage (303) and is also connected to the throttle orifice (305).

2. The compact gasoline engine cylinder head structure according to claim 1, characterized in that: The first cylinder head assembly (100) also includes an exhaust side oil return port (103) and an intake side port (104) respectively disposed at the outer end of the front cylinder head (101).

3. The compact gasoline engine cylinder head structure according to claim 2, characterized in that: The working space (G) is composed of an oil chamber (G1), a valve guide bottom hole (G2), an air passage (G3), a combustion chamber (G4), and a return oil guide cavity (G5), and the oil chamber (G1) and the return oil guide cavity (G5) are connected.

4. The compact gasoline engine cylinder head structure according to claim 3, characterized in that: The valve guide bottom hole (G2) connects the air passage (G3) and the oil chamber (G1), and the oil return hole (102) is hollow.

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