Cylinder gas extraction structure and engine crankcase ventilation system

Abstract

The utility model discloses a kind of cylinder body gas taking structure and engine crankcase ventilation system, cylinder body gas taking structure includes cylinder body and gas passage;Cylinder body is configured in crankcase, and at least two air inlets and gas outlets are formed;Gas passage is formed in the inside of cylinder body, gas passage has starting segment and end segment from bottom to top arrangement and intercommunication, the starting segment of gas passage is connected with at least two air inlets, and the end segment of gas passage is connected with gas outlet;The device is by setting at least two air inlets with height difference, effectively avoid the situation that all air inlets are submerged due to engine inclination, acceleration or braking and the like working condition cause oil liquid level fluctuation, simultaneously, at least one air inlet avoids crank connecting rod oil throwing area, can greatly reduce the oil amount inhaled, improve the efficiency of gas-liquid separation.

Description

Technical Field

[0001] This utility model relates to the field of engine technology, specifically to a cylinder block air intake structure and an engine crankcase ventilation system. Background Technology

[0002] During engine operation, some high-pressure combustible mixture or exhaust gas in the combustion chamber can leak into the crankcase through the piston ring gaps; this is called blow-by. Blow-by can cause increased pressure inside the crankcase, potentially leading to problems such as oil leaks and seal damage. Furthermore, unburned fuel and water vapor contained in blow-by can dilute and contaminate the engine oil, affecting the engine's lubrication efficiency and lifespan.

[0003] To address the aforementioned issues, existing engines generally employ crankcase ventilation systems. For example, patent CN208669378U discloses a crankcase ventilation system and a vehicle equipped with such a system, including an engine block and an oil-gas separator, with the oil-gas separator mounted on the cylinder block. This crankcase ventilation system moves the oil-gas separator from the cylinder head to the cylinder block, lowering its installation position and moving it further away from the cold cylinder head, thus reducing contact with cold outside air. This increases the operating temperature of the oil-gas separator, reduces internal water vapor condensation, and ultimately reduces oil emulsification and dilution.

[0004] However, the existing solutions mentioned above rely on a single air intake, which means that gas and blow-by gas must flow through the same channel via this single intake, which is not conducive to reducing the oil content in the crankcase blow-by gas. Furthermore, when the engine is tilted, accelerating, or braking, the oil level fluctuates, easily submerging the air intake. This not only prevents effective gas extraction but may also draw in large amounts of liquid oil, leading to abnormal oil consumption and affecting the oil-gas separator's separation efficiency. Utility Model Content

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a cylinder block air intake structure and an engine crankcase ventilation system to solve the technical problems in the prior art where the air intake port is singular and the flow of gas and blow-by gas in the same channel is not conducive to reducing oil content.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, this utility model provides a cylinder block air intake structure, including a cylinder block body and a gas passage; the cylinder block body is disposed in a crankcase and has at least two air inlets and an air outlet; the gas passage is formed inside the cylinder block body, the gas passage having a starting section and a ending section arranged from bottom to top and connected, the starting section of the gas passage being connected to at least two of the air inlets, and the ending section of the gas passage being connected to the air outlet; wherein, the air inlets have a height difference in the vertical direction, and the height of at least one air inlet is not lower than the crankshaft centerline of the crankcase, the air inlet being configured to introduce gas into the starting section, guide it through the ending section, and then exit it through the air outlet.

[0007] In some embodiments, the height of at least one of the air intakes is not lower than the crankshaft centerline of the crankcase.

[0008] In some embodiments, at least two air inlets include: a first air inlet and a second air inlet; the height of the first air inlet is not lower than the crankshaft centerline of the crankcase; the height of the second air inlet is lower than the height of the first air inlet.

[0009] In some embodiments, the second air intake is disposed on the bottom surface of the cylinder body.

[0010] In some embodiments, the central axis of the gas channel extends in a non-linear manner.

[0011] In some embodiments, the cylinder block air intake structure further includes an oil-gas separation structure, wherein the air inlet of the oil-gas separation structure is connected to the air outlet and is used to separate the oil and gas from the gas discharged from the air outlet.

[0012] In some embodiments, the oil-gas separation structure includes: a separator inlet pipe, a pre-separator, and a separator body; one end of the separator inlet pipe is connected to the outlet; the pre-separator is disposed in the separator inlet pipe and is used to perform preliminary oil-gas separation on the incoming gas; the inlet end of the separator body is connected to the other end of the separator inlet pipe and is used to perform further oil-gas separation on the gas pre-separated by the pre-separator.

[0013] In some embodiments, the separator inlet pipe includes a reflux section, which is one end of the separator inlet pipe near the outlet; the pre-separator is disposed in the reflux section; and the inner wall of the reflux section is configured as a liquid reflux channel of the pre-separator, which is smoothly connected to the inner wall of the gas channel to guide the liquid separated by the pre-separator back into the gas channel.

[0014] In some embodiments, the pre-separator includes several sets of separation sections, which are arranged sequentially along the axial direction of the separator inlet pipe.

[0015] In some possible embodiments, each group of the separation section includes a plurality of grid plates; the plurality of grid plates are spaced apart and arranged in parallel within the separator inlet pipe; the side of each grid plate near the outlet is an inclined surface, the inclined surface being configured to impact and guide droplets in the oil-gas mixture to converge downwards.

[0016] Secondly, this utility model also provides an engine crankcase ventilation system, including the cylinder block intake structure as described in any of the above.

[0017] Compared with existing technologies, the cylinder block air intake structure and engine crankcase ventilation system provided by this utility model, by setting up a cylinder block body, a gas passage, at least two air inlets, and an air outlet, and utilizing at least two air inlets with a height difference in the vertical direction, effectively prevents oil level fluctuations from submerging all air inlets under different operating conditions, ensuring that at least one air inlet can normally draw gas, thus improving the reliability and stability of air intake. The height of at least one air inlet is not lower than the crankshaft centerline of the crankcase, avoiding the oil slinging area of ​​the crankshaft and connecting rod, reducing the amount of oil drawn into the air inlet, and further improving the gas-liquid separation effect. By arranging and connecting the initial and final sections from bottom to top, the gas can undergo preliminary gas-liquid separation by gravity when flowing within the passage, reducing the amount of oil drawn out with the gas. This design facilitates the reduction of oil content in crankcase blow-by gases, improving the performance and efficiency of the entire engine crankcase ventilation system, extending engine life, and reducing various problems caused by abnormal oil consumption and poor oil-gas separator performance, thus providing strong support for stable engine operation. Simultaneously, this design integrates the intake, exhaust, and gas passages onto the cylinder block, simplifying the overall structure and providing better insulation against blow-by gases, reducing the risk of water vapor condensation, oil emulsification, and icing. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the cylinder block air intake structure and the engine crankcase ventilation system provided in this embodiment of the utility model; Figure 2 This is a schematic diagram of the cylinder block air intake structure and the pre-separator installation of the engine crankcase ventilation system provided in this embodiment of the utility model; Figure 3 This is a schematic diagram of the first air intake of the cylinder block air intake structure and the engine crankcase ventilation system provided in this embodiment of the utility model.

[0019] Explanation of reference numerals in the attached figures: 1. Cylinder body; 2. Gas passage; 3. Inlet; 31. First inlet; 32. Second inlet; 4. Outlet; 5. Oil-gas separation structure; 51. Separator inlet pipe; 511. Return section; 52. Pre-separator; 521. Grille plate; 53. Separator body. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0021] To address the technical problems of a single air intake and the co-flow of gas and blow-by gas, which are detrimental to reducing oil content, this invention provides a cylinder block air intake structure and an engine crankcase ventilation system. By setting at least two air intakes with a height difference, it effectively avoids the situation where all air intakes are submerged due to oil level fluctuations caused by engine tilting, acceleration, or braking. At the same time, at least one air intake avoids the crankshaft and connecting rod oil slinging area, which can significantly reduce the amount of oil drawn in and improve the efficiency of gas-liquid separation.

[0022] Please see Figures 1 to 3 In a first aspect, embodiments of this application provide a cylinder block air intake structure, including a cylinder block body 1 and a gas passage 2; the cylinder block body 1 is disposed in a crankcase and has at least two air inlets 3 and air outlets 4; the gas passage 2 is formed inside the cylinder block body 1, and the gas passage 2 has a starting section and a ending section arranged from bottom to top and connected to each other, the starting section of the gas passage 2 is connected to the air inlets 3; the ending section of the gas passage 2 is connected to the air outlets 4; wherein, the air inlets 3 have a height difference in the vertical direction, and the height of at least one air inlet 3 is not lower than the crankshaft centerline of the crankcase, and the air inlets 3 are configured to introduce gas into the starting section, guide it through the ending section, and then discharge it through the air outlets 4.

[0023] In this device, the gas passage 2 is arranged from bottom to top and connected through its initial and final sections. This allows for preliminary gas-liquid separation due to gravity as the gas flows within the passage, reducing the amount of oil extracted with the gas. Simultaneously, at least two air inlets 3 with a vertical height difference effectively prevent oil level fluctuations from submerging all air inlets 3 under different operating conditions, such as engine tilting, acceleration, or braking. This ensures that at least one air inlet 3 can normally extract gas, improving the reliability and stability of gas extraction. The height of at least one air inlet 3 is not lower than the crankshaft centerline of the crankcase, avoiding the oil-throwing area of ​​the crankshaft and connecting rod, reducing the amount of oil drawn into the air inlet 3, and further enhancing the gas-liquid separation effect. After being guided by the final section within the gas passage 2, the gas is discharged through the air outlet 4, preventing situations where a single air inlet is submerged, resulting in ineffective gas extraction or the extraction of large amounts of liquid oil. Meanwhile, the multi-intake design also increases the diversity of gas flow paths, which helps to further reduce the oil content in crankcase blow-by and improve the oil-gas separation effect.

[0024] Preferably, please refer to Figure 1 In this embodiment, two air inlets 3 are provided, including a first air inlet 31 and a second air inlet 32 ​​respectively. The height of the first air inlet 31 is not lower than the crankshaft centerline of the crankcase; the height of the second air inlet 32 ​​is lower than the height of the first air inlet 31. Under normal operating conditions, crankcase blow-by gas enters the gas passage 2 through the first air inlet 31 and the second air inlet 32. When the second air inlet 32 ​​is blocked by the oil level, crankcase blow-by gas only enters the gas passage 2 through the first air inlet 31. The first air inlet 31 avoids the crankshaft and connecting rod oil slinging area, so the amount of oil drawn in during the gas extraction process is small, thereby effectively reducing the oil content in the extracted gas.

[0025] Furthermore, in some possible embodiments, the second air intake 32 is located on the bottom surface of the cylinder block 1, which can fully collect the gas that escapes from various parts of the crankcase, ensure the pressure balance in the crankcase, and avoid affecting the normal operation of the engine due to excessively high or low local pressure.

[0026] Please see Figure 1In some possible embodiments, the central axis of the gas passage 2 extends non-linearly, forming a pre-cast channel on the engine block. The gas passage 2 is located between two cylinders within the crankcase. When blow-by gas flows within the passage, its flow direction changes multiple times due to the altered orientation of the gas passage 2. Due to their different inertia, the liquid oil adheres more readily to the inner wall of the passage when the flow direction changes, achieving initial separation of the liquid oil. After separation, the oil on the inner wall of the passage gradually converges and flows downwards, eventually returning to the crankcase. This effectively reduces the amount of oil discharged with the gas, prevents rapid cooling and condensation of the blow-by gas in the crankcase, and reduces water vapor condensation and oil emulsification within the crankcase.

[0027] Of course, in other possible embodiments, the number and layout of the air inlets 3 and outlets 4 can be adjusted according to actual needs. For example, more air inlets can be added to meet the gas extraction requirements under different operating conditions, further improving the flexibility and efficiency of gas extraction. At the same time, the position and size of the outlets 4 can also be optimized to ensure that the gas can be discharged smoothly, avoiding the formation of pressure or turbulence inside the cylinder, which would affect the gas-liquid separation effect. In addition, the shape design of the air inlets 3 and outlets 4 can also be diversified, such as using circular, elliptical, or other irregular shapes, to better adapt to the characteristics of gas flow and improve the performance of the entire cylinder gas extraction structure.

[0028] Please see Figure 1 In order to completely separate the liquid oil in the gas, in some possible embodiments, an oil-gas separation structure 5 is also provided. The inlet end of the oil-gas separation structure 5 is connected to the outlet 4 and is used to separate the oil and gas from the gas discharged from the outlet 4.

[0029] Preferably, please refer to Figure 1 and Figure 2 In this embodiment, the oil-gas separation structure 5 includes a separator inlet pipe 51, a pre-separator 52, and a separator body 53. One end of the separator inlet pipe 51 is connected to the outlet 4. The pre-separator 52 is disposed inside the separator inlet pipe 51 and is used to perform preliminary oil-gas separation on the incoming gas. The inlet end of the separator body 53 is connected to the other end of the separator inlet pipe 51 and is used to further separate the oil-gas from the gas after pre-separation by the pre-separator 52. This design directly connects the separator inlet pipe 51 to the outlet 4 formed on the cylinder block body 1, which can quickly guide crankcase blow-by gas into the pre-separator 52 and the separator body 53. The top of the cylinder block body 1 is closed, eliminating the existing structure of setting the outlet 4 on the cylinder head, making the overall structure more compact. At the same time, it significantly shortens the pipeline design length between the crankcase outlet 4 on the cylinder block and the oil-gas separator, shortening the external blow-by gas flow pipeline and reducing the risk of water vapor condensation.

[0030] During operation, the gas is guided through the end of gas channel 2 and enters the separator inlet pipe 51 through outlet 4. The pre-separator 52 first performs preliminary filtration on the gas, intercepting larger oil droplets, and then the gas enters the separator body 53 to complete deep separation.

[0031] It should be noted that the exhaust port of the separator body 53 can be configured to either openly discharge into the atmosphere or connect to a pre-pressure pipeline for closed-loop circulation. When open-loop discharge into the atmosphere is used, the separator body 53 directly discharges the deeply separated gas into the surrounding environment. When closed-loop circulation is selected by connecting to a pre-pressure pipeline, the separated gas is introduced into the pre-pressure pipeline and re-enters the system's circulation. This closed-loop circulation method effectively avoids direct gas discharge into the atmosphere, reducing environmental pollution and improving gas utilization.

[0032] Further, please refer to Figure 1 and Figure 2 In some possible embodiments, the separator inlet pipe 51 includes a return section 511, which is the end of the separator inlet pipe 51 near the outlet 4. The pre-separator 52 is disposed in the return section 511, and the inner wall of the return section 511 forms a liquid return channel for the pre-separator 52, which guides the oil separated by the pre-separator 52 back to the crankcase. The liquid return channel is smoothly connected to the inner wall of the gas channel 2, and its horizontal or downward sloping design towards the outlet 4 ensures that the oil naturally returns to the crankcase under gravity, avoiding the accumulation or stagnation of oil during the return process due to improper channel design.

[0033] Specifically, please refer to Figure 1 and Figure 2 The pre-separator 52 includes several sets of separation sections arranged sequentially along the axial direction of the separator inlet pipe 51. Each set of separation sections includes several grid plates 521; these grid plates 521 are spaced apart and arranged parallel to each other within the separator inlet pipe 51; the side of each grid plate 521 closest to the outlet 4 is an inclined surface, configured to impact and guide droplets in the oil-gas mixture downwards to converge. The lower end of the inclined surface of each grid plate 521 faces the outlet 4. When the high-speed oil-gas mixture impacts the inclined surface of the grid plate 521, the droplets adhere and coalesce more effectively due to inertia. The inclined surface of the grid plate 521 simultaneously provides a clear guide for the coalesced droplets, causing them to flow rapidly downwards. This integrates the efficient grid separation module directly into the return section 511 adjacent to the outlet 4, achieving "separation equals return." The separated droplets can instantly slide down the inclined surface to the inner wall of the return section 511 and return directly due to gravity.

[0034] Preferably, please refer to Figure 1 and Figure 2In this embodiment, two sets of separation sections are provided. In the set of separation sections near the air outlet 4, a gap is reserved between the bottom of the grille plate 521 and the bottom of the separator inlet pipe 51. In the set of separation sections away from the air outlet 4, the grille plate 521 is tightly fitted or fixedly sealed to the wall of the separator inlet pipe 51. This design allows a small amount of incompletely separated liquid oil to pass through the gap between the grille plate 521 and the pipe wall near the air outlet 4 during gas flow and flow back to the gas channel 2. The bottom of the grille plate 521 away from the air outlet 4 is tightly fitted or fixedly sealed to the wall of the separator inlet pipe 51, which can further intercept the liquid oil and prevent it from continuing to flow forward with the gas, thereby achieving a relatively fine oil-liquid separation effect in the pre-separation stage.

[0035] It should be noted that, in this embodiment, the specific form of the separator body 53 is not particularly limited, as long as it can meet the requirement of further oil-gas separation of the gas pre-separated by the pre-separator 52. The separator body 53 can adopt various forms such as centrifugal separation structure, filter element separation structure, or composite separation structure.

[0036] Secondly, embodiments of this application also provide an engine crankcase ventilation system, including a cylinder block intake structure as described in any of the above embodiments.

[0037] To better understand this utility model, the following is combined with... Figures 1 to 3 The technical solution of this utility model is described in detail below: During operation, crankcase blow-by gas first enters the gas passage 2 of the cylinder block 1 through two intake ports with a height difference. When the engine is under normal operating conditions, the first intake port 31 and the second intake port 32 operate simultaneously. After entering through the initial section, the gas undergoes preliminary gas-liquid separation by gravity and a non-linear flow channel during its upward flow. If special operating conditions such as engine tilting, acceleration, or braking occur, causing the second intake port 32 to be submerged by the oil level, crankcase blow-by gas enters the gas passage 2 only through the first intake port 31.

[0038] After being guided through the end of gas channel 2, the gas enters the separator inlet pipe 51 through outlet 4. The pre-separator 52 first performs preliminary filtration of the gas, intercepting larger oil droplets. The intercepted oil droplets slide down the inclined surface of the grid plate 521 and the liquid return channel, eventually flowing back to gas channel 2 under gravity and then back to the crankcase. The gas, after preliminary treatment by the pre-separator 52, continues to flow along the separator inlet pipe 51 and enters the separator body 53, where fine separation occurs. Afterward, any gas leaks are either openly discharged into the atmosphere or connected to the pre-pressurization pipeline for closed-loop circulation.

[0039] This invention features at least two air inlets with a vertical height difference. The first air inlet 31 is at a height no lower than the crankshaft centerline of the crankcase, and the second air inlet 32 ​​is located on the bottom surface of the cylinder block 1. This design avoids the oil spillage area of ​​the crankshaft and connecting rod, reducing the amount of oil drawn into the air inlet 3 and further improving the gas-liquid separation effect. Under normal operating conditions, crankcase blow-by gas enters the gas passage 2 through the first air inlet 31 and the second air inlet 32. Under different operating conditions, such as engine tilting, acceleration, or braking, when the second air inlet 32 ​​is blocked by the oil level, crankcase blow-by gas can still enter the gas passage 2 through the first air inlet 31. This effectively prevents oil level fluctuations from flooding all air inlets 3, ensuring that at least one air inlet 3 can normally extract gas, thus improving the reliability and stability of gas extraction.

[0040] This invention features a bottom-up, interconnected initial and final section, allowing for preliminary gas-liquid separation via gravity as gas flows through the channel, reducing the amount of engine oil extracted with the gas. Furthermore, the central axis of the gas channel 2 is designed to extend non-linearly. During gas flow, the tortuous path allows liquid engine oil to adhere more easily to the channel's inner wall, facilitating preliminary separation of the liquid oil. This also prevents rapid cooling and condensation of crankcase blow-by gas, reducing water vapor condensation and oil emulsification within the crankcase.

[0041] This design also facilitates the reduction of oil content in crankcase blow-by, improving the performance and efficiency of the entire engine crankcase ventilation system, extending engine life, and reducing various problems caused by abnormal oil consumption and poor oil-gas separator performance, thus providing strong support for stable engine operation. Simultaneously, this design integrates the intake port 3, exhaust port 4, and gas passage 2 onto the cylinder block body 1, simplifying the overall structure and providing better insulation against blow-by, reducing the risk of water vapor condensation, oil emulsification, and icing.

[0042] In the description of this application, it should be noted that the terms "upper" and "lower," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0043] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0044] The specific embodiments of this utility model described above do not constitute a limitation on the scope of protection of this utility model. Any other corresponding changes and modifications made based on the technical concept of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A cylinder block air intake structure, characterized in that, include: The cylinder block body is located inside the crankcase and has at least two air inlets and air outlets. A gas passage is formed inside the cylinder body. The gas passage has a starting section and a ending section arranged from bottom to top and connected to each other. The starting section of the gas passage is connected to at least two of the air inlets, and the ending section of the gas passage is connected to the air outlet. The air inlet has a height difference in the vertical direction, and the height of at least one air inlet is not lower than the crankshaft centerline of the crankcase. The air inlet is configured to introduce gas into the starting section, guide it through the ending section, and then discharge it through the outlet.

2. The cylinder block air intake structure according to claim 1, characterized in that, At least two air intakes include: The first air intake, the height of which is not lower than the crankshaft centerline of the crankcase; and The second air intake is lower in height than the first air intake.

3. The cylinder block air intake structure according to claim 2, characterized in that, The second air intake is located on the bottom surface of the cylinder body.

4. The cylinder block air intake structure according to claim 1, characterized in that, The central axis of the gas channel extends in a non-linear manner.

5. The cylinder block air intake structure according to claim 1, characterized in that, It also includes an oil-gas separation structure, wherein the inlet end of the oil-gas separation structure is connected to the outlet, and is used to separate the oil and gas in the gas discharged from the outlet.

6. The cylinder block air intake structure according to claim 5, characterized in that, The oil-gas separation structure includes: The separator inlet pipe has one end connected to the outlet. A pre-separator, installed inside the separator inlet pipe, is used for preliminary oil-gas separation of the incoming gas; and The separator body has its air inlet end connected to the other end of the separator air inlet pipe, and is used to further separate oil and gas in the gas that has been pre-separated by the pre-separator.

7. The cylinder block air intake structure according to claim 6, characterized in that, The separator inlet pipe includes a reflux section, which is the end of the separator inlet pipe near the outlet. The pre-separator is disposed in the reflux section; and the inner wall of the reflux section is configured as a liquid reflux channel of the pre-separator, the liquid reflux channel being smoothly connected to the inner wall of the gas channel to guide the liquid separated by the pre-separator back to the gas channel.

8. The cylinder block air intake structure according to claim 7, characterized in that, The pre-separator includes several sets of separation sections, which are arranged sequentially along the axial direction of the separator inlet pipe.

9. The cylinder block air intake structure according to claim 8, characterized in that, Each of the separation sections includes several grid plates; Several of the aforementioned grid plates are spaced apart and arranged parallel to each other inside the separator inlet pipe; the side of each grid plate near the outlet is an inclined surface, which is configured to impact and guide droplets in the oil-gas mixture to converge downwards.

10. An engine crankcase ventilation system, characterized in that, Includes the cylinder intake structure as described in any one of claims 1-9.

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