Oil-gas separation system for engine crankcase, engine and vehicle

Abstract

The invention relates to the technical field of vehicles, and particularly discloses an oil-gas separation system for an engine crankcase, an engine and a vehicle, and the oil-gas separation system for the engine crankcase comprises a box body, an oil-gas separator and an exhaust pipeline. Due to the fact that gas in a negative pressure gas inlet pipe of a gas compressor in the supercharger is negative pressure, an oil-gas mixture in a crankcase is pumped into a crankcase body under the action of the negative pressure, gas separated by an oil-gas separator can enter the supercharger to serve as part of gas supplement, and the gas and fresh air jointly enter an engine to participate in combustion; moreover, along with the improvement of the operation working condition of the engine, the oil-gas mixture in the crankcase is increased, the rotating speed of the supercharger is increased, and the air inlet negative pressure is also increased, at the moment, the pressure difference generated by the supercharger and the crankcase is increased, and the oil-gas mixture extracted from the crankcase is increased, so that the effect of keeping the pressure in the crankcase in a normal range under the full working condition is realized; and the whole process does not need manual control.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular to an oil and gas separation system for an engine crankcase, an engine and a vehicle. Background Art

[0002] At present, when an internal combustion engine is in normal working condition, as the power increases, the oil and gas pressure in the crankcase will increase. The main reasons for the increase in pressure are as follows: 1. Due to the reciprocating motion of the piston, the temperature inside the engine is relatively high, which will generate a certain amount of oil vapor; 2. The piston ring or cylinder liner is worn, resulting in the escape of combustion exhaust gas along the worn part; 3. Too much oil is filled, resulting in an increase in oil and gas generated by evaporation. However, the increase in crankcase pressure will have an adverse impact on the safety and life of the internal combustion engine. For example: 1. Oil leakage: The increase in pressure in the crankcase will cause oil to leak from the engine cover, crankshaft oil seal, etc.; 2. Decrease in lubrication performance: The increase in crankcase pressure may cause too much gas to be mixed into the oil, reducing the lubrication performance of the oil and increasing engine wear; 3. If the pressure is too high, it will cause the explosion-proof door of the crankcase to pop open, resulting in the abnormal operation of the diesel engine. Therefore, an oil and gas separation system is usually set up to discharge the pressure in the crankcase. However, in the existing oil and gas separation system, according to the required value of the crankcase pressure under different working conditions, the operator needs to observe the pressure value while adjusting the adjustment handle to control the pressure within the safe range, resulting in low work efficiency and time-consuming and laborious. Summary of the Invention

[0003] The purpose of the present invention is to provide an oil and gas separation system for an engine crankcase, an engine and a vehicle, so as to solve the problem that in the existing oil and gas separation system, the operator needs to adjust the adjustment handle to control the pressure in the crankcase within the safe range, resulting in low work efficiency and time-consuming and laborious.

[0004] On the one hand, the present invention provides an oil and gas separation system for an engine crankcase. The oil and gas separation system for an engine crankcase includes: a box body, which is installed on the crankcase and communicated with the cavity of the crankcase; an oil and gas separator, which is installed on the box body and communicated with the cavity of the box body, and the oil and gas separator is used to separate the oil and gas mixture entering the cavity of the box body from the crankcase; an extraction pipeline, one end of the extraction pipeline is communicated with the air outlet of the oil and gas separator, and the other end of the extraction pipeline can be communicated with the negative pressure intake pipe of the compressor in the supercharger; wherein, when the engine gear gradually increases, the air pressure of the oil and gas mixture in the crankcase gradually increases, and at the same time, the speed of the supercharger gradually increases, and the negative pressure in the negative pressure intake pipe gradually increases, so that the pressure difference between the negative pressure in the negative pressure intake pipe and the air pressure of the oil and gas mixture in the crankcase becomes larger, so as to increase the extraction amount of the oil and gas mixture in the crankcase.

[0005] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the negative pressure in the negative pressure intake pipe is Y, with the unit of -kpa, and the blow-by gas volume of the crankcase is X, with the unit of l / min. Then: Y = A 1 *exp(-X / t 1 ) + A 2 *exp(-X / t 2 ) + Y 0 ; where A 1 、A 2 、t 1 、t 2 、Y 0 are all constants.

[0006] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the oil-gas separation system for the engine crankcase further includes a safety valve, and the safety valve is arranged on the crankcase.

[0007] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the throughput of the oil-gas separator is greater than the maximum blow-by gas volume of the crankcase.

[0008] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the suction pipeline includes a first suction pipe and a second suction pipe that are connected to each other. The first suction pipe is connected to the air outlet of the oil-gas separator, and the second suction pipe is connected to the negative pressure intake port of the supercharger.

[0009] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the first suction pipe includes a suction pipe body and a plurality of connecting pipes. One ends of the plurality of connecting pipes are all connected to the suction pipe body. There are a plurality of oil-gas separators, and the plurality of oil-gas separators are installed on the box body at intervals. The other ends of the connecting pipes are connected to the air outlets of the oil-gas separators, and the plurality of connecting pipes and the plurality of oil-gas separators are arranged in one-to-one correspondence.

[0010] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the oil-gas separation system for the engine crankcase further includes a connecting piece. One end of the connecting piece is connected to the suction pipeline, and the other end of the connecting piece is connected to the box body.

[0011] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the oil-gas separation system for the engine crankcase further includes an oil return pipeline. One end of the oil return pipeline is connected to the bottom of the box body, and the other end of the oil return pipeline is connected to the oil return channel of the crankcase.

[0012] As an alternative technical solution for the oil-gas separation system of the engine crankcase, the housing has a main oil return passage and a branch oil return passage. One end of the branch oil return passage is communicated with the oil-gas separator, the other end of the branch oil return passage is communicated with one end of the main oil return passage, and the other end of the main oil return passage is communicated with one end of the oil return pipeline.

[0013] On the other hand, the present invention provides an engine, including a crankcase and the oil-gas separation system for the engine crankcase in any of the above solutions. The housing is installed on the crankcase and communicated with the cavity of the crankcase.

[0014] In still another aspect, the present invention provides a vehicle, including a vehicle body and the engine in any of the above solutions. The engine is installed on the vehicle body.

[0015] The beneficial effects of the present invention are as follows:

[0016] The present invention provides an oil-gas separation system for an engine crankcase. The oil-gas separation system for the engine crankcase includes a housing, an oil-gas separator, and an extraction pipeline. By using the oil-gas separation system for the engine crankcase of the present invention, since the gas in the negative pressure intake pipe of the compressor in the supercharger is negative pressure, one end of the extraction pipeline is communicated with the air outlet of the oil-gas separator, and the other end of the extraction pipeline can be communicated with the negative pressure intake pipe. In this way, the oil-gas mixture in the crankcase can be pumped into the housing by the action of the negative pressure. Subsequently, the oil-gas separator is used to separate the oil-gas mixture. At the same time, the separated gas can enter the supercharger as a part of the gas supplement and enter the engine to participate in combustion together with fresh air, further improving the fuel efficiency of the engine. Moreover, as the operating condition of the engine improves, the oil-gas mixture in the crankcase increases, and at the same time, the speed of the supercharger increases, and the intake negative pressure also increases. At this time, the pressure difference generated with the crankcase becomes larger, and the oil-gas mixture extracted from the crankcase increases accordingly, realizing the function of keeping the pressure in the crankcase within the normal range under all operating conditions, and the whole process does not require manual control, effectively solving the problem that the oil-gas separation system in the prior art requires the operator to control the pressure in the crankcase within the safe range by adjusting the adjusting handle, which has low working efficiency and is time-consuming and laborious. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the oil-gas separation system for the engine crankcase in the embodiment of the present invention installed on the supercharger;

[0018] Figure 2 It is a schematic structural diagram of the oil-gas separation system for the engine crankcase in the embodiment of the present invention;

[0019] Figure 3Schematic diagram of the installation structure of the oil-gas separator on the box body in the embodiment of the present invention;

[0020] Figure 4 Cross-sectional view of the box body and the oil-gas separator in the embodiment of the present invention;

[0021] Figure 5 Cross-sectional view of the box body and the oil-gas separator from another angle in the embodiment of the present invention.

[0022] In the figure:

[0023] 1. Box body; 11. Main oil return channel; 12. Branch oil return channel;

[0024] 2. Oil-gas separator;

[0025] 3. Air extraction pipeline; 31. First air extraction pipe; 311. Air extraction pipe body; 312. Connecting pipe; 32. Second air extraction pipe;

[0026] 4. Supercharger; 41. Compressor;

[0027] 5. Connector;

[0028] 6. Oil return pipeline. Specific implementation manners

[0029] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and moreover, the first feature being "above", "above" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "below" and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the first feature has a lower horizontal height than the second feature.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0032] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0033] As Figures 1 to 5 shown, this embodiment provides an oil-gas separation system for an engine crankcase. The oil-gas separation system for the engine crankcase includes a housing 1, an oil-gas separator 2, and a suction pipeline 3. Among them, the housing 1 is installed on the crankcase and is in communication with the cavity of the crankcase; the oil-gas separator 2 is installed on the housing 1 and is in communication with the cavity of the housing 1. The oil-gas separator 2 is used to separate the oil-gas mixture entering the cavity of the housing 1 from the crankcase; one end of the suction pipeline 3 is in communication with the air outlet of the oil-gas separator 2, and the other end of the suction pipeline 3 can be in communication with the negative pressure intake pipe of the compressor 41 in the supercharger 4; among them, when the engine gear gradually increases, the air pressure of the oil-gas mixture in the crankcase gradually increases, and at the same time, the rotational speed of the supercharger 4 gradually increases, and the negative pressure in the negative pressure intake pipe gradually increases, so that the pressure difference between the negative pressure in the negative pressure intake pipe and the air pressure of the oil-gas mixture in the crankcase becomes larger, so as to increase the extraction amount of the oil-gas mixture in the crankcase.

[0034] By adopting the oil-gas separation system for the engine crankcase of the present invention, since the negative-pressure intake pipe of the compressor 41 in the supercharger 4 is under negative pressure, one end of the suction pipeline 3 is communicated with the air outlet of the oil-gas separator 2, and the other end of the suction pipeline 3 can be communicated with the negative-pressure intake pipe. In this way, the oil-gas mixture in the crankcase can be pumped to the casing 1 by the action of negative pressure, and then the oil-gas separator 2 is used to separate the oil-gas mixture. At the same time, the separated gas can enter the supercharger 4 as a part of gas supplement, and enter the engine together with fresh air to participate in combustion, further improving the fuel efficiency of the engine. Moreover, as the operating condition of the engine improves, the oil-gas mixture in the crankcase increases, and at the same time, the rotational speed of the supercharger 4 increases, and the intake negative pressure also increases. At this time, the pressure difference generated with the crankcase becomes larger, and the oil-gas mixture extracted from the crankcase increases accordingly, realizing the function of keeping the pressure in the crankcase within the normal range under all working conditions, and the whole process does not require manual control, effectively solving the problem that the oil-gas separation system in the prior art requires the operator to control the pressure in the crankcase within the safe range by adjusting the adjusting handle, resulting in low work efficiency and time-consuming and laborious problems.

[0035] Among them, since the casing 1 is relatively close to the supercharger 4, it is not necessary to install a very long suction pipeline 3 and it will not cause system pressure loss.

[0036] It should be noted that as the operating gear of the engine increases, the combustion in the cylinder intensifies, and the amount of oil-gas leakage in the crankcase also gradually increases. For example: when the engine runs in the 1st gear, the leakage amount is 209 l / min, and when the diesel engine runs in the 12th gear, the leakage amount is 2189.2 l / min.

[0037] At the same time, as the operating gear of the engine increases, the intake pressure of the supercharger gradually increases. When the engine runs in the 1st gear, the intake negative pressure is 0.09 kPa, and when the engine runs in the 12th gear, the intake negative pressure is 3.38 kPa. Therefore, the suction capacity of the oil-gas separation system for the engine crankcase of the present invention also increases accordingly.

[0038] Moreover, this oil-gas separation system for the engine crankcase is installed on the D180-16 type diesel engine, and the alarm value of the crankcase pressure is 4.5 kPa. The pressure in the crankcase can be automatically controlled. During the whole working condition operation process, the pressure in the crankcase can be controlled below 3 kPa, far lower than the alarm value, and safe operation can be achieved.

[0039] Specifically, the negative pressure in the negative-pressure intake pipe is Y, with the unit of -kPa, and the amount of oil-gas leakage in the crankcase is X, with the unit of l / min, then: Y = A 1 *exp(-X / t 1 ) + A 2 *exp(-X / t2 ) + Y 0 ; wherein, A1 = -1128.25, A2 = -1807.11, t1 = 0.09, t2 = 1.16, Y0 = 2292.59. In this way, the negative pressure in the negative pressure intake pipe required can be judged according to the blow-by gas volume of the crankcase, so as to achieve the purpose of extracting the oil-gas mixture from the crankcase.

[0040] The oil-gas separation system for the engine crankcase further includes a safety valve, and the safety valve is arranged on the crankcase. In this way, when the speed of the speed increaser is not high, the pressure of the oil-gas mixture in the crankcase can be prevented from being too high, and the oil-gas mixture in the crankcase can be discharged through the safety valve to ensure that the pressure in the crankcase is within the normal range value.

[0041] Specifically, in this embodiment, the through-flow rate of the oil-gas separator 2 is greater than the maximum blow-by gas volume of the crankcase. Such a setting can ensure the full separation of the oil-gas mixture in the crankcase by the oil-gas separator 2 and improve the separation effect. The number of the oil-gas separators 2 is multiple and can be obtained by calculation. In the present invention, the maximum blow-by gas volume of the crankcase under the rated condition of the diesel engine is: for a new engine, it is 3065.2 l / min, and after depreciation, multiplying by the coefficient 1.5, the blow-by gas volume is 4597.9 l / min. The through-flow rate of each selected oil-gas separator 2 in this solution is 300 l / min. Therefore, a total of 16 oil-gas separators 2 are installed, 8 on each side, which can meet the actual requirements.

[0042] The through-flow rate of the oil-gas separator 2 refers to its ability to process the oil-gas mixture per unit time, that is, it represents the gas flow rate that the oil-gas separator can process under the rated condition; the maximum blow-by gas volume of the crankcase refers to the wear degree and sealing performance of the engine cylinder piston assembly, and its value is significantly affected by the engine type, working condition and technical state. Specifically, according to different working conditions, the intake air volume of the diesel engine can be calculated. According to experience, for a new engine, the blow-by gas volume of the crankcase is about 0.9% times the intake air volume, and after depreciation, the blow-by gas volume of the crankcase is about 1.5% times the intake air volume.

[0043] As Figure 1 and Figure 2 shown, the suction pipeline 3 includes a first suction pipe 31 and a second suction pipe 32 that are connected to each other. The first suction pipe 31 is connected to the air outlet of the oil-gas separator 2, which is convenient for connecting multiple oil-gas separators 2 at the same time. At the same time, the second suction pipe 32 is connected to the negative pressure intake port of the supercharger 4, which is convenient for transporting the separated gas to the negative pressure intake port of the supercharger 4.

[0044] Further, in order to connect multiple oil and gas separators 2 simultaneously, in this embodiment, the first suction pipe 31 includes a suction pipe body 311 and multiple connecting pipes 312. One ends of the multiple connecting pipes 312 are all connected to the suction pipe body 311. There are multiple oil and gas separators 2, and the multiple oil and gas separators 2 are installed on the box body 1 at intervals. The other ends of the connecting pipes 312 are connected to the air outlets of the oil and gas separators 2, and the multiple connecting pipes 312 and the multiple oil and gas separators 2 are arranged in one-to-one correspondence. With this arrangement, it is ensured that the air outlets of the multiple oil and gas separators 2 can all be transported to the suction pipe body 311 through the connecting pipes 312, and then the suction pipe body 311 is used to transport the gas to the second suction pipe 32.

[0045] As Figure 2 shown, in order to ensure the stability and safety of the suction pipe line 3, in this solution, the oil and gas separation system for the engine crankcase further includes a connecting member 5. One end of the connecting member 5 is connected to the suction pipe line 3, and the other end of the connecting member 5 is connected to the box body 1. In this way, the suction pipe line 3 can be fixed to the box body 1 through the connecting member 5, thereby ensuring the stability and safety of the suction pipe line 3 during operation. Among them, the connecting member 5 includes but is not limited to a connecting piece or a connecting rod, etc., and is connected to the suction pipe line 3 and the box body 1 respectively by means of bolt connection.

[0046] In this embodiment, in order to ensure cleanliness and avoid causing secondary pollution, the oil and gas separation system for the engine crankcase further includes an oil return pipeline 6. One end of the oil return pipeline 6 is connected to the bottom of the box body 1, and the other end of the oil return pipeline 6 is connected to the oil return passage of the crankcase. With this arrangement, the oil separated by the oil and gas separator 2 can directly flow back to the crankcase through the oil return pipeline 6, avoiding causing secondary pollution.

[0047] Specifically, in order to ensure that the oil separated by the multiple oil and gas separators 2 all flows back to the crankcase, the box body 1 has a main oil return passage 11 and a branch oil return passage 12. One end of the branch oil return passage 12 is connected to the oil and gas separator 2, the other end of the branch oil return passage 12 is connected to one end of the main oil return passage 11, and the other end of the main oil return passage 11 is connected to one end of the oil return pipeline 6. In this way, the oil separated by the multiple oil and gas separators 2 collected by the branch oil return passage 12 flows to the main oil return passage 11 uniformly, and then flows to the oil return pipeline 6 through the main oil return passage 11.

[0048] This embodiment also provides an engine, which includes a crankcase and the oil-gas separation system for the engine crankcase in the above solution. The housing 1 is installed on the crankcase and is in communication with the cavity of the crankcase. In the engine adopting the present invention, since the intake port of the supercharger is under negative pressure, one end of the suction pipeline 3 is connected to the air outlet of the oil-gas separator 2, and the other end of the suction pipeline 3 can be connected to the negative-pressure intake port of the supercharger 4. In this way, the oil-gas mixture in the crankcase can be drawn into the housing 1 by the action of negative pressure. Subsequently, the oil-gas separator 2 is used to separate the oil-gas mixture. At the same time, the separated gas can enter the supercharger 4 as a part of the gas supplement, and enter the engine to participate in combustion together with fresh air, further improving the fuel efficiency of the engine. Moreover, as the operating condition of the engine improves, the oil-gas mixture in the crankcase increases, and at the same time, the rotational speed of the supercharger 4 increases, and the intake negative pressure also increases. At this time, the pressure difference generated with the crankcase becomes larger, and the oil-gas mixture drawn from the crankcase increases accordingly, achieving the effect of keeping the pressure in the crankcase within the normal range under all operating conditions, and the entire process does not require manual control.

[0049] This embodiment further provides a vehicle, which includes a vehicle body and the engine in the above solution. The engine is installed on the vehicle body. Since it includes the above engine, the vehicle in the embodiment of the present invention has all the advantages and beneficial effects of the above embodiment, which will not be elaborated here.

[0050] The advantages of the oil-gas separation system for the engine crankcase of the present invention are as follows;

[0051] The present invention directly connects the suction pipeline to the negative-pressure intake port of the supercharger, skillfully utilizes the action of negative pressure to draw the oil-gas mixture in the crankcase into the housing, and at the same time uses the oil-gas separator for separation. Subsequently, the separated gas can directly enter the supercharger, and after being compressed by the supercharger, it enters the cylinder of the engine to participate in combustion. Moreover, as the operating condition of the engine improves, the oil-gas mixture in the crankcase increases, and at the same time, the rotational speed of the supercharger 4 increases, and the intake negative pressure also increases. At this time, the pressure difference generated with the crankcase becomes larger, and the oil-gas mixture drawn from the crankcase increases accordingly, achieving the effect of keeping the pressure in the crankcase within the normal range under all operating conditions, and the entire process does not require manual control. And the engine oil separated by the oil-gas separator 2 can directly flow back to the crankcase through the oil return pipeline 6, avoiding secondary pollution. Among them, the structure of the present invention is simple and does not require auxiliary equipment (such as a fan) to be installed outside the engine.

[0052] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. An oil-gas separation system for an engine crankcase, characterized in that: include: A housing (1) is mounted on the crankcase and communicated with the cavity of the crankcase; An oil-gas separator (2) is mounted on the housing (1) and is in communication with the cavity of the housing (1), wherein the oil-gas separator (2) is used to separate the oil-gas mixture from the crankcase that enters the cavity of the housing (1); An air extraction pipeline (3), one end of the air extraction pipeline (3) being connected to the air outlet of the oil-gas separator (2), and the other end of the air extraction pipeline (3) being able to be connected to the negative pressure air inlet pipe of the air compressor (41) in the supercharger (4); When the engine gear gradually increases, the air pressure of the oil-gas mixture in the crankcase gradually increases, and at the same time, the rotation speed of the supercharger (4) gradually increases, and the negative pressure in the negative pressure intake pipe gradually increases, so that the pressure difference between the negative pressure in the negative pressure intake pipe and the air pressure of the oil-gas mixture in the crankcase becomes larger, so as to increase the amount of oil-gas mixture extracted from the crankcase.

2. The oil-gas separation system for an engine crankcase according to claim 1, characterized in that: The negative pressure in the negative pressure intake pipe is Y, in units of -kpa, and the blowby volume of the crankcase is X, in units of l / min, then: Y=A1*exp(-X / t1)+A2*exp(-X / t2)+Y0; Among them, A1, A2, t1, t2, and Y0 are all constants.

3. The oil-gas separation system for an engine crankcase according to claim 1, characterized in that: The oil-gas separation system for the engine crankcase further comprises a safety valve, which is arranged on the crankcase.

4. The oil-gas separation system for an engine crankcase according to claim 1, characterized in that: The flow rate of the oil-gas separator (2) is greater than the maximum blowby gas volume of the crankcase.

5. The oil-gas separation system for an engine crankcase according to claim 1, characterized in that: The air extraction pipeline (3) comprises a first air extraction pipe (31) and a second air extraction pipe (32) which are connected to each other, wherein the first air extraction pipe (31) is connected to the air outlet of the oil-gas separator (2), and the second air extraction pipe (32) is connected to the negative pressure air inlet of the supercharger (4).

6. The oil-gas separation system for an engine crankcase according to claim 5, characterized in that: The first air extraction pipe (31) comprises an air extraction pipe body (311) and a plurality of connecting pipes (312), one end of each of the plurality of connecting pipes (312) being connected to the air extraction pipe body (311), the plurality of oil-gas separators (2) being installed on the housing (1) at intervals, the other end of the connecting pipe (312) being connected to an air outlet of the oil-gas separator (2), and the plurality of connecting pipes (312) and the plurality of oil-gas separators (2) being arranged in a one-to-one correspondence.

7. The oil-gas separation system for an engine crankcase according to claim 1, characterized in that: The oil-gas separation system for the engine crankcase further comprises a connecting piece (5), one end of the connecting piece (5) is connected to the air extraction pipeline (3), and the other end of the connecting piece (5) is connected to the case (1).

8. The oil-gas separation system for an engine crankcase according to any one of claims 1 to 7, characterized in that: The oil-gas separation system for the engine crankcase further comprises an oil return pipeline (6), one end of the oil return pipeline (6) being connected to the bottom of the case (1), and the other end of the oil return pipeline (6) being connected to the oil return channel of the crankcase.

9. The oil-gas separation system for an engine crankcase according to claim 8, characterized in that: The housing (1) comprises a main oil return passage (11) and a branch oil return passage (12); one end of the branch oil return passage (12) is in communication with the oil-gas separator (2); the other end of the branch oil return passage (12) is in communication with one end of the main oil return passage (11); and the other end of the main oil return passage (11) is in communication with one end of the oil return pipeline (6).

10. An engine, characterized in that: It comprises a crankcase and an oil-gas separation system for an engine crankcase according to any one of claims 1 to 9, wherein the case (1) is mounted on the crankcase and communicated with a cavity of the crankcase.

11. A vehicle, characterized in that: The invention comprises a vehicle body and the engine according to claim 10, wherein the engine is mounted on the vehicle body.

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