Internal combustion engine

Abstract

To provide a further improved internal combustion engine.SOLUTION: An internal combustion engine includes: an oil separator including an oil separation chamber capable of storing oil and gas therein; a first passage connected to a space between a bearing housing of a turbocharger and the oil separation chamber to introduce oil-containing gas from the bearing housing to the oil separation chamber; a second passage connected to a space between the oil separation chamber and an intake passage to discharge gas from the oil separation chamber to the intake passage; a third passage connected to a space between the oil separation chamber and a crank chamber of a cylinder block to discharge oil from the oil separation chamber to the crank chamber; and a pressure valve that is disposed in the second passage, opens when pressure in the oil separation chamber exceeds a threshold value and closes when the pressure in the oil separation chamber is the threshold value or lower.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to internal combustion engines. [Background technology]

[0002] Patent Document 1 discloses an internal combustion engine including an engine, an intake passage connected to the engine, and an exhaust passage connected to the engine. The internal combustion engine further includes a turbocharger and an oil tank that receives oil from the turbocharger through an oil passage. The oil tank stores oil and blow-by gas therein. The oil tank supplies oil to the engine through an oil supply passage and supplies blow-by gas to the intake passage through a blow-by gas passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-196864 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable to reduce the oil mist content in the blow-by gas supplied to the intake passage. [Means for solving the problem]

[0005] An internal combustion engine according to one embodiment of the present disclosure includes an oil separator including an oil separation chamber capable of storing oil and gas therein, a first passage connected between a bearing housing of a turbocharger and the oil separation chamber for introducing oil-containing gas from the bearing housing to the oil separation chamber, a second passage connected between the oil separation chamber and an intake passage for discharging gas from the oil separation chamber to the intake passage, a third passage connected between the oil separation chamber and a crank chamber of a cylinder block for discharging oil from the oil separation chamber to the crank chamber, and a pressure valve disposed in the second passage for opening when pressure in the oil separation chamber exceeds a threshold value and closing when pressure in the oil separation chamber is equal to or lower than the threshold value. Effect of the Invention

[0006] The present disclosure provides an improved internal combustion engine. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a configuration diagram showing an internal combustion engine according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a configuration diagram showing the oil separator according to the first embodiment of the present disclosure. [Diagram 3] FIG. 3 is a configuration diagram showing an oil separator according to a second embodiment of the present disclosure. [Figure 4] FIG. 4 is a configuration diagram showing an oil separator according to a third embodiment of the present disclosure. [Diagram 5] FIG. 5 is a configuration diagram showing an oil separator according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] As shown in Fig. 1, in this embodiment, an internal combustion engine 10 includes a cylinder block 12. The cylinder block 12 includes a cylinder 15 and a piston 16 slidably disposed within the cylinder 15. The cylinder block 12 includes a combustion chamber 13 formed by the cylinder 15 and the piston 16. The cylinder block 12 also includes a crank chamber 14 disposed below the combustion chamber 13. The crank chamber 14 includes an oil pan 17 therein.

[0009] The internal combustion engine 10 further includes an intake passage 21 connected to the combustion chamber 13. The intake passage 21 may include, for example, an air cleaner, an intercooler, and a throttle valve.

[0010] The internal combustion engine 10 further includes an exhaust passage 22 connected to the combustion chamber 13. The exhaust passage 22 may include a catalytic converter and a silencer.

[0011] The internal combustion engine 10 further includes a turbocharger 30. In this embodiment, the turbocharger 30 includes a compressor wheel 31, a turbine wheel 32, and a rotor shaft 33 connected between the compressor wheel 31 and the turbine wheel 32. The compressor wheel 31 is disposed in the intake passage 21. The turbine wheel 32 is disposed in the exhaust passage 22. The turbocharger 30 further includes a bearing housing 34 that rotatably houses the rotor shaft 33.

[0012] The internal combustion engine 10 may further include a breather hose 23 connected between the crank chamber 14 and the intake passage 21. Specifically, the breather hose 23 may be connected to a first position 51 of the intake passage 21. The first position 51 may be located between the air cleaner and the compressor wheel 31.

[0013] The internal combustion engine 10 may further include a ventilation hose 24 connected between the crank chamber 14 and the intake passage 21, and a PCV valve 25 disposed in the ventilation hose 24. Specifically, the ventilation hose 24 may be connected to a second position 52 of the intake passage 21. The second position 52 may be located, for example, between the compressor wheel 31 and the combustion chamber 13. The PCV valve 25 allows the flow of blow-by gas from the crank chamber 14 to the intake passage 21 and prevents the flow of blow-by gas from the intake passage 21 to the crank chamber 14.

[0014] The internal combustion engine 10 further includes an oil separator 40 that includes an oil separation chamber 41 .

[0015] The internal combustion engine 10 further includes a first passage 26 (oil return pipe) connected between the bearing housing 34 and the oil separation chamber 41. The first passage 26 is a passage for introducing oil used for lubricating the rotor shaft 33 in the bearing housing 34 into the oil separation chamber 41. The inside of the bearing housing 34 may contain exhaust gas that has leaked from the exhaust passage 22 into the bearing housing 34 after passing through a sealing in the turbocharger 30. This exhaust gas may also flow into the oil separation chamber 41 through the first passage 26 together with the oil. Hereinafter, the exhaust gas and oil that pass through the first passage 26 will be collectively referred to as oil-containing gas.

[0016] The internal combustion engine 10 further includes a second passage 27 connected between the oil separation chamber 41 and the intake passage 21. The second passage 27 is a passage for discharging the exhaust gas that has passed through the first passage 26 and flowed into the oil separation chamber 41 to the intake passage 21. Specifically, the second passage 27 may be connected to a third position 53 of the intake passage 21. The third position 53 may be located between the first position 51 and the compressor wheel 31, for example.

[0017] The internal combustion engine 10 further includes a third passage 28 connected between the oil separation chamber 41 and the crank chamber 14. The third passage 28 is a passage for discharging oil from the oil separation chamber 41 to the crank chamber 14.

[0018] Exhaust gas may flow into the oil separation chamber 41 through the first passage 26. Also, the oil supplied from the first passage 26 and the oil in the oil separation chamber 41 may turn into mist and accumulate in the oil separation chamber 41. For this reason, in this embodiment, a device is provided to prevent the oil mist in the oil separation chamber 41 from flowing into the intake passage 21 through the second passage 27, and a device is provided to prevent the exhaust gas in the oil separation chamber 41 from flowing into the crank chamber 14 through the third passage 28. These devices are described below.

[0019] The internal combustion engine 10 further includes a pressure valve 29 disposed in the second passage 27. The pressure valve 29 opens when the pressure in the oil separation chamber 41 exceeds a threshold value, and closes when the pressure in the oil separation chamber 41 is equal to or lower than the threshold value. For example, when the pressure of the gas in the oil separation chamber 41 exceeds the threshold value, the pressure valve 29 opens and discharges the gas to the second passage 27. As a result, the pressure of the gas in the oil separation chamber 41 becomes equal to or lower than the threshold value, and the pressure valve 29 closes. After a while, the pressure of the gas in the oil separation chamber 41 exceeds the threshold value again, and the pressure valve 29 opens and discharges the gas to the second passage 27. Since the pressure valve 29 opens intermittently, the oil separator 40 can secure a time for retaining the oil-containing gas in the oil separation chamber 41, and the possibility that the oil-containing gas is discharged directly through the second passage 27 can be reduced. This makes it possible to suppress the oil mist in the oil separation chamber 41 from flowing into the intake passage 21 through the second passage 27.

[0020] The threshold value of the pressure valve 29 may be determined based on various design concepts. For example, the threshold value of the pressure valve 29 may be determined so that the pressure valve 29 is always closed while the turbocharger 30 is stopped, and the pressure valve 29 opens and closes intermittently while the turbocharger 30 is operating. In addition, the threshold value of the pressure valve 29 may be determined so that when the oil level 66 of the oil 65 drops due to an increase in the pressure of the gas in the oil separation chamber 41, the pressure of the gas in the oil separation chamber 41 can be adjusted so that the oil level 66 does not become lower than the third opening 63, as described below.

[0021] 2 to 5 show specific embodiments of the oil separator 40. As shown in FIG. 2, the oil separator 40a may be integrated with the cylinder block 12. Specifically, the oil separator 40a includes a housing 42 that forms an oil separation chamber 41. Meanwhile, the cylinder block 12 has a housing 18 that forms the crank chamber 14. The housing 42 of the oil separator 40 is partially shared with the housing 18 of the cylinder block 12. However, this is not limited to the above, and the housing 42 may be a separate body from the cylinder block 12.

[0022] The oil separator 40a has a first opening 61, a second opening 62, and a third opening 63. The first opening 61 is connected to the first passage 26. The second opening 62 is connected to the second passage 27. The third opening 63 is connected to the third passage 28. In this embodiment, since the oil separator 40 is integrated with the cylinder block 12, the third opening 63 can serve as the third passage 28.

[0023] The oil separator 40a stores the oil 65 in the oil separation chamber 41. The third opening 63 is located below the oil level 66 of the oil 65 stored in the oil separation chamber 41. This allows the oil separator 40a to discharge only the oil 65 in the oil separation chamber 41 to the third passage 28. In this embodiment, as shown in FIG. 2, the oil separator 40a has an oil receiver 64 that protrudes into the crank chamber 14 of the cylinder block 12. The oil receiver 64 communicates with the oil separation chamber 41 through the third opening 63. The upper limit of the oil level 66 of the oil 65 can be adjusted by the height of the wall surface of the oil receiver 64. The oil 65 overflows the oil receiver 64 and falls from the oil separation chamber 41 to the oil pan 17. The height of the wall surface of the oil receiver 64 is set to be higher than the third opening 63.

[0024] Alternatively, as shown in FIG. 3, the oil separator 40b may include a valve 76 that opens and closes the third opening 63 depending on the weight of the oil 65 in the oil separation chamber 41. The valve 76 may include a spring 77 and a piston head 78 connected to the spring 77. The piston head 78 forms the bottom surface of the oil separation chamber 41 partially or entirely. The piston head 78 receives an upward pressing force from the spring 77 and a downward pressing force from the oil 65. The piston head 78 moves up and down depending on the balance between the upward pressing force and the downward pressing force, thereby opening and closing the third opening 63. The upper limit of the oil level 66 of the oil 65 can be adjusted by the elastic force of the spring 77.

[0025] Alternatively, as shown in FIG. 4, the oil separator 40c may include a valve 79 that opens and closes the third opening 63 depending on the weight of the oil 65 in the oil separation chamber 41. The valve 79 may include a spring 80 and a piston head 81 connected to the spring 80. The piston head 81 forms the bottom surface of the oil separation chamber 41 partially or entirely. The piston head 81 receives an upward pulling force from the spring 80 and a downward pushing force from the oil 65. The piston head 81 moves up and down depending on the balance between the upward pulling force and the downward pushing force, thereby opening and closing the third opening 63. The upper limit of the oil level 66 of the oil 65 can be adjusted by the elastic force of the spring 80.

[0026] In this embodiment, by adjusting the upper limit of the oil level 66, the first opening 61 is positioned above the oil level 66 of the oil 65 stored in the oil separation chamber 41. Similarly, the second opening 62 is positioned above the oil level 66 of the oil 65 stored in the oil separation chamber 41. Since the second opening 62 is positioned above the oil level 66 of the oil 65, the oil separator 40a can discharge only the gas in the oil separation chamber 41 to the second passage 27.

[0027] In this embodiment, the oil separator 40a includes second oil cutting plates 69, 70. The second oil cutting plates 69, 70 are disposed in the oil separation chamber 41, inclined downward, and overlap the second opening 62 partially or entirely in the vertical direction. For example, the second oil cutting plate 69 is provided on the first opening 61 side of the second opening 62 and inclined downward so as to move away from the first opening 61, and the second oil cutting plate 70 is provided on the opposite side of the first opening 61 of the second opening 62 and inclined downward so as to approach the first opening 61. The second oil cutting plates 69, 70 bend the airflow of the gas discharged from the oil separation chamber 41 to the second passage 27. Oil mist carried by the airflow of the exhaust gas collides with and adheres to the second oil cutting plates 69, 70. By inclining the second oil cutting plates 69, 70, the adhered oil falls downward. The number of second oil cutting plates 69, 70 is not limited to two, but may be one, or three or more.

[0028] The oil separator 40a may include a first oil cutting plate 68 in addition to the second oil cutting plates 69, 70 or instead of the second oil cutting plates 69, 70. The first oil cutting plate 68 is disposed in the oil separation chamber 41, inclined downward so as to move away from the second passage 27 (or the second opening 62), and overlaps the first opening 61 partially or entirely in the vertical direction. The first oil cutting plate 68 directs the oil that has flowed in from the first opening 61 in a direction away from the second opening 62 in the oil separation chamber 41. The first oil cutting plate 68 prevents the oil-containing gas from being immediately discharged from the second passage 27, and can suppress the oil that has flowed in from the first opening 61 from colliding with the oil surface 66 and becoming mist-like. The number of the first oil cutting plates 68 is not limited to one, and may be two or more.

[0029] The pressure valve 29 may take various forms. For example, as shown in Fig. 2, the pressure valve 29 may include a spring 71 and a piston head 72 connected to the spring 71. The piston head 72 receives a downward pressing force from the spring 71 and an upward pressing force from the gas in the oil separation chamber 41. The piston head 72 moves up and down depending on the balance between the downward pressing force and the upward pressing force, thereby opening and closing the second opening 62. The threshold of the pressure valve 29 can be adjusted by the elastic force of the spring 71.

[0030] 3, the pressure valve 29 may include a spring 73 and an opening / closing door 74 connected to the spring 73. The opening / closing door 74 receives a pressing force in a closing direction from the spring 73, and also receives a pressing force in an opening direction from the gas in the oil separation chamber 41. The opening / closing door 74 opens and closes the second opening 62 depending on the balance between the pressing force in the closing direction and the pressing force in the opening direction. The threshold of the pressure valve 29 can be adjusted by the elastic force of the spring 73.

[0031] 4, the pressure valve 29 may include a piston head 75. The piston head 75 receives an upward pushing force from the gas in the oil separation chamber 41. The piston head 75 moves up and down according to the balance between the downward force due to its own weight and the upward pushing force, thereby opening and closing the second opening 62. The threshold of the pressure valve 29 can be adjusted by the weight of the piston head 75.

[0032] 5, the second opening 62 may be closer to the cylinder block 12 than the first opening 61. Whether the oil separator 40d is integrated with the cylinder block 12 or separate from the cylinder block 12, this makes the pressure valve 29 more susceptible to heat from the cylinder block 12, and prevents the pressure valve 29 from freezing or sticking in other ways.

[0033] The oil separator 40a may also be located vertically above the oil pan 17. This allows the oil to return to the oil pan 17 by its own weight. The oil separator 40a may also be located vertically below the cylinder 15. This prevents the inside of the oil separation chamber 41 from becoming too hot due to the heat of the cylinder 15. [Explanation of symbols]

[0034] 10 Internal combustion engine 12 Cylinder block 13 Combustion chamber 14 Crankcase 21 Intake passage 22 Exhaust passage 29 Pressure valve 30 Turbocharger 31 Compressor wheel 32 Turbine wheel 33 Rotor shaft 34 Bearing housing 40 Oil Separator 41 Oil separation chamber

Claims

1. an oil separator including an oil separation chamber capable of storing oil and gas therein; a first passageway connected between a bearing housing of a turbocharger and the oil separation chamber for conducting oil-containing gas from the bearing housing to the oil separation chamber; a second passage connected between the oil separation chamber and the intake passage for discharging gas from the oil separation chamber to the intake passage; a third passage connected between the oil separation chamber and a crank chamber of a cylinder block for discharging oil from the oil separation chamber to the crank chamber; a pressure valve disposed in the second passage, the pressure valve opening when the gas pressure in the oil separation chamber exceeds a threshold value and closing when the gas pressure in the oil separation chamber is equal to or lower than the threshold value; Equipped with The oil separation chamber has a second opening connected to the second passage, The second opening is located above the oil level of the oil stored in the oil separation chamber, The oil separator further includes a second oil cutting plate disposed in the oil separation chamber, The second oil cutting plate is inclined downward and overlaps with the second opening in the vertical direction, The oil separation chamber has a first opening connected to the first passage, The first opening is located above the oil level of the oil stored in the oil separation chamber, The oil separator further includes a first oil cutting plate disposed in the oil separation chamber, The first oil cutting plate is inclined downward toward a wall portion that forms the oil separation chamber so as to move away from the second passage, and overlaps with the first opening in the vertical direction, and a lower end of the first oil cutting plate is located lower than a lower end of the second oil cutting plate. Internal combustion engine.

2. The oil separation chamber has a third opening connected to the third passage, The third opening is located below the oil level of the oil stored in the oil separation chamber.

2. The internal combustion engine of claim 1.

3. The oil separator is integrated into the cylinder block.

3. An internal combustion engine according to claim 1 or 2.

4. The oil separation chamber has a first opening connected to the first passage and a second opening connected to the second passage, The second opening is closer to the cylinder block than the first opening. An internal combustion engine according to any one of claims 1 to 3.

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