engine

Abstract

To provide an engine capable of enhancing a gas-liquid separation effect of fluid.SOLUTION: An engine E includes: a crank shaft 2 that converts a reciprocating motion of a piston 3 to a rotating motion; a crank case 4 that supports the crank shaft 2; a cylinder 6 projecting from the crank case 4 to one side in a piston reciprocating direction; an oil pan 14 mounted to a lower side of the crank case 4 to form a fluid collecting space SP for collecting oil that has lubricated a lubricated portion within the crank case 4; and a scavenging pump 30 for sucking the oil from inside of the fluid collecting space SP and discharging the oil to an oil tank 28. A breather intake port 38a is formed at a position facing the fluid collecting space SP from above.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an engine used, for example, as a drive source of a vehicle.

Background Art

[0002] An engine may be used as a drive source of a vehicle such as a motorcycle (for example, Patent Document 1). In such an engine, a crankcase breather is provided to release the pressure inside the crankcase to the outside. The fluid taken into the crankcase breather is gas-liquid separated, and then the gas component is sent to the intake passage and the liquid component is sent to the oil pan.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] From the viewpoint of enhancing the gas-liquid separation effect, it is preferable that the fluid supplied to the crankcase breather has less liquid component. Therefore, the breather intake port for taking in the fluid is preferably provided in a place where the agitation of the oil is small. For example, the cam chamber of the cylinder head where the camshaft rotates or the crank chamber of the crankcase where the crankshaft rotates is not preferable. The inside of the oil pan below the crankcase has little agitation of the oil, but since it is filled with oil, it has been difficult to provide a breather intake port.

[0005] The disclosure of the present application provides an engine capable of enhancing the gas-liquid separation effect of the fluid.

Means for Solving the Problems

[0006] The engine of the present disclosure includes a crankshaft that converts the reciprocating motion of a piston into rotational motion, a crankcase that supports the crankshaft, a cylinder that protrudes from one side of the crankcase in the piston reciprocating direction, an oil pan that is attached below the crankcase and forms a liquid collection space for collecting oil that lubricates lubricated parts in the crankcase, and a scavenge pump that sucks oil from the liquid collection space and discharges it to an oil tank. A breather intake port is formed at a position facing the liquid collection space from above.

Advantages of the Invention

[0007] According to the engine of the present disclosure, since the oil collected in the oil pan is discharged by the scavenge pump, the liquid level of the oil in the oil pan does not rise. Therefore, it is possible to prevent the liquid component of the oil in the oil pan from flowing from the breather intake port toward the breather chamber, and the gas-liquid separation effect of the fluid is improved. In particular, if the breather intake port is arranged at a position facing the liquid collection space of the oil pan from above, that is, at a high position inside the oil pan, it is less likely to be affected by the liquid level of the oil. As a result, it becomes difficult for the liquid component to be taken in from the breather intake port, and the gas-liquid separation effect of the fluid is improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present disclosure will be described with reference to FIGS. 1 to 9. The engine E of the present embodiment is a reciprocating engine, and is used, for example, in an airplane in which a propeller is arranged at the tip of the fuselage. In this case, the engine E is housed in the fuselage, and the engine power is transmitted to the propeller. The use of the engine E is not limited to this, and it can also be applied, for example, as a driving source for ships, and can also be applied as a driving source for vehicles such as motorcycles and four-wheeled vehicles.

[0010] In the following description, the "width direction WD" refers to the direction in which the crankshaft 2 of the engine E extends, that is, the axial direction of the crankshaft 2. In the width direction WD, the direction toward the center in the width direction is referred to as the "inner side in the width direction", and the direction away from the center in the width direction is referred to as the "outer side in the width direction". The "reciprocating direction VD" refers to the reciprocating motion direction of the piston of the engine E. The direction orthogonal to both the "width direction WD" and the "reciprocating direction VD" is referred to as the "orthogonal direction PD".

[0011] The engine E of the present embodiment is a six-cylinder engine in which six cylinders are arranged in the direction in which the crankshaft 2 extends. However, the number of cylinders is not limited to this, and it may be, for example, four cylinders. Further, the engine E of the present embodiment is a gasoline engine, but the fuel is not limited to gasoline. The crankshaft 2 converts the reciprocating motion of the piston 3 into a rotational motion.

[0012] The engine E has a crankcase 4 that supports a crankshaft 2, a cylinder 6 that protrudes from the crankcase 4 in one direction of the reciprocating direction VD, and a cylinder head 8 that is connected to the protruding end of the cylinder 6. The crankshaft 2 is disposed in a crank chamber 5 inside the crankcase 4. In the following description, in the reciprocating direction VD, the direction in which the cylinder 6 protrudes from the crankcase 4 is referred to as "upward", and the opposite side is referred to as "downward".

[0013] The crankcase 4 is divided into upper and lower parts, and has a crankcase lower 4a and a crankcase upper 4b. In the present embodiment, the crankcase upper 4b and the cylinder 6 are integrally formed by molding. However, the crankcase upper 4b and the cylinder 6 may be separate. In the following description, the integrally formed crankcase upper 4b and cylinder 6 is referred to as a cylinder block 10.

[0014] The engine E further has a head cover 12 connected to the upper end of the cylinder head 8. A cam chamber is formed by the cylinder head 8 and the cylinder head cover 12. A valve operating mechanism for opening and closing intake and exhaust valves in conjunction with the rotation of the crankshaft 2 is disposed in the cam chamber.

[0015] The engine E further has an oil pan 14 connected to the lower end of the crankcase 4. Engine oil for lubricating lubricated parts of the engine E is stored in the oil pan 14. In other words, a liquid collecting space SP for collecting oil that has lubricated lubricated parts of the engine E is formed in the oil pan 14.

[0016] In the present embodiment, the crankcase upper 4b constitutes a first case half connected to the cylinder 6. On the other hand, the crankcase lower 4a constitutes a second case half to which the oil pan 14 is connected.

[0017] An intake port 16 opens on one side (the right side in FIG. 1) of the cylinder head 8 in the orthogonal direction PD, and an exhaust port 18 opens on the other side end (the left side in FIG. 1) of the cylinder head 8 in the orthogonal direction PD. In the following description, the intake port side in the orthogonal direction PD is simply referred to as the "intake side", and the exhaust port side is simply referred to as the "exhaust side".

[0018] The intake port 16 and the exhaust port 18 are passages formed inside the cylinder head 8. The upstream end of the intake port 16 opens on one side of the cylinder head 8 in the orthogonal direction PD, and the downstream end opens into the combustion chamber 20 inside the cylinder 6. The upstream end of the exhaust port 18 opens into the combustion chamber 20 inside the cylinder 6, and the downstream end opens in front of the other side of the cylinder head 8 in the orthogonal direction PD. The intake port 16 is formed for each cylinder. Similarly, the exhaust port 18 is also formed for each cylinder.

[0019] External air is supplied as intake air from the intake port 16 to the combustion chamber 20, and fuel is injected from the injector 22 into the combustion chamber 20 to form a mixture of fuel and air. The mixture in the combustion chamber 20 is ignited by the spark plug 24 and burns. The exhaust gas after combustion is led out of the engine from the exhaust port 18.

[0020] FIG. 2 is a front view of the engine E as viewed from the intake side in the orthogonal direction PD. As shown in the figure, an output shaft 25 and a speed reduction mechanism 26 are provided on one side (the right side in FIG. 2) in the width direction WD of the engine E. The rotational force of the crankshaft 2 is reduced by the speed reduction mechanism 26 and transmitted to the output shaft 25. An aircraft propeller, vehicle wheels, turbine rotor blades, compressor impellers, etc. are connected to the output shaft 25 directly or via a power transmission member.

[0021] The engine E of the present disclosure is an engine with a dry sump lubrication system having a scavenge pump 30 that sucks oil from the oil collecting space SP of the oil pan 14 and discharges it to the oil tank 28.

[0022] In the present embodiment, the oil tank 28 is provided outside the engine E, that is, spaced apart from the engine E. The oil discharged from the scavenge pump 30 is stored in the oil tank 28 and then pressurized by the feed pump 32 to lubricate the lubricated parts of the engine E. The oil after lubricating the lubricated parts is returned to the oil pan 14 through the vertical passage 27 (FIG. 3). The vertical passage 27 is a passage that communicates the crankcase 5 and the oil pan 14.

[0023] In the present embodiment, the oil pan 14 has a bottom wall 14a that constitutes the deepest part, and an inclined wall 14b that extends upward and inclines in the horizontal direction, in the present embodiment, away from the engine width direction WD from the bottom wall 14a.

[0024] In the present embodiment, the scavenge pump 30 is disposed inside the oil pan 14. Specifically, the scavenge pump 30 is disposed at the deepest part of the oil pan 14. The scavenge pump 30 sucks the oil in the oil collecting space SP of the oil pan 14 and discharges it to the outside of the oil collecting space SP. Therefore, in the oil pan 14, the oil level does not rise, and there are many gas components of the oil in the oil collecting space SP.

[0025] In the present embodiment, the scavenge pump 30 is driven in conjunction with the rotation of the crankshaft 2. Specifically, the rotational force of the crankshaft 2 is transmitted to the scavenge pump 30 by a power transmission member 34 such as a drive chain.

[0026] In the present embodiment, the feed pump 32 is also disposed inside the oil pan 14. Specifically, the feed pump 32 is disposed at the deepest part of the oil pan 14 and on the other side (the left side in FIG. 2) in the engine width direction WD inside the oil pan 14. The scavenge pump 30 and the feed pump 32 are arranged side by side in the engine width direction WD.

[0027] In this embodiment, the feed pump 32 is also driven in conjunction with the rotation of the crankshaft 2. Specifically, the rotational force of the crankshaft 2 is transmitted to the feed pump 32 by a power transmission member 34 such as a drive chain.

[0028] In this embodiment, the rotational force of the crankshaft 2 is transmitted to both the scavenge pump 30 and the feed pump 32 by a common power transmission member 34. Specifically, the rotation axis 30a of the scavenge pump 30 and the rotation axis 32a of the feed pump 32 are coaxially arranged, and both rotation axes 30a and 32a are connected. The power transmission member 34 is spanned over the rotation axis 32a of the feed pump 32, and the rotational force of the crankshaft 2 is transmitted to the rotation axis 32a of the feed pump 32 and the rotation axis 30a of the scavenge pump 30 connected thereto via the power transmission member 34.

[0029] When the engine E starts, the scavenge pump 30 and the feed pump 32 are driven in conjunction with the rotation of the crankshaft 2. The feed pump 32 pumps the oil stored in the oil tank 28 to the lubricated parts of the engine E. The oil after lubricating the lubricated parts is returned to the oil pan 14 via the upper and lower passages 27. The oil in the liquid collection space SP of the oil pan 14 is recovered by the scavenge pump 30, cooled by the oil cooler 35, and then supplied to the oil tank 28.

[0030] Next, the breather structure 36 of the crankcase 4 of the engine E of this embodiment will be described. The inside of the crankcase 4 is at a higher pressure than the outside air due to blow-by gas and oil vapor. The breather structure 36 of the crankcase 4 is provided to release such pressure, that is, the fluid inside the engine to the outside.

[0031] The breather structure 36 has a breather introduction passage 38, a breather chamber 40, a breather discharge passage 42, and a return passage 44. The fluid F inside the crankcase 4 is taken in from the breather introduction passage 38 and flows into the breather chamber 40. The fluid F is separated into a gas component Fg and a liquid component Fl in the breather chamber 40. The gas component Fg is sent through the breather discharge passage 42 to the intake system of the engine E and supplied to the combustion chamber 20 (FIG. 1) together with the intake air. The liquid component Fl is returned to the inside of the crankcase 4 through the return passage 44. This will be described in detail below.

[0032] The breather introduction passage 38 of the present embodiment is an internal passage formed inside the crankcase 4. Specifically, the breather introduction passage 38 is formed near the intake-side wall surface in the orthogonal direction PD in the crankcase 4. More specifically, the breather introduction passage 38 is formed on one side (the right side in FIG. 2) in the engine width direction WD of the intake-side wall surface of the crankcase 4.

[0033] The breather introduction passage 38 extends in the vertical direction, and the breather intake port 38a at the lower end opens into the liquid collection space SP of the oil pan 14, and the breather outlet 38b at the upper end opens into the breather chamber 40.

[0034] The breather intake port 38a is arranged at a position facing the liquid collection space SP of the oil pan 14 from above. In the vertical direction, the breather intake port 38a is arranged at a position higher than the suction port 30b of the scavenge pump 30. Further, the breather intake port 38a is formed at a part above the mating surface 45 between the crankcase 4 and the oil pan 14.

[0035] Specifically, the breather intake port 38a is formed in the crankcase lower 4a of the crankcase 4 and is arranged inside the mating surface 45, that is, on the liquid collection space SP side, as shown in FIG. 3 when the crankcase 4 is viewed from below.

[0036] As shown in FIG. 2, with respect to the engine width direction WD, the breather intake port 38a is arranged to face the inclined wall 14b of the oil pan 14. That is, the breather intake port 38a is arranged above the inclined wall 14b of the oil pan 14. Further, the breather intake port 38a is arranged on one side in the engine width direction WD rather than the scavenge pump 30. In the present embodiment, the breather intake port 38a is arranged near the wall surface on one side in the engine width direction WD of the oil pan 14.

[0037] As shown in FIG. 4, a standing wall 46 is provided around the breather intake port 38a at the lower end of the crankcase 4. The standing wall 46 prevents oil from flowing toward the breather intake port 38a. In the present embodiment, the standing wall 46 is integrally formed with the crankcase 4 by molding. The standing wall 46 extends in a direction VD intersecting the axial direction of the crankshaft 2, that is, the engine width direction WD.

[0038] The standing wall 46 is arranged between the vertical passage 45 and the breather intake port 38a. In the present embodiment, on the intake side in the orthogonal direction PD and on one side in the engine width direction WD (the right side in FIG. 4) with respect to the breather intake port 38a, a wall of the crankcase 4 is provided. The standing wall 46 is provided on the exhaust side in the orthogonal direction PD and on the other side in the engine width direction WD (the left side in FIG. 4) with respect to the breather intake port 38a. That is, the breather intake port 38a is substantially entirely surrounded by the wall of the crankcase 4 and the standing wall 46.

[0039] As shown in FIG. 2, a breather chamber 40 is formed in the crankcase upper 4b of the crankcase 4. Specifically, the breather chamber 40 is provided on the intake port side in the orthogonal direction PD in the crankcase 4. The fluid taken in from the breather intake port 38a is supplied to the breather chamber 40. The breather chamber 40 has a plurality of rooms, and the fluid is gas-liquid separated by repeatedly flowing into and out of the rooms.

[0040] In this embodiment, the breather chamber 40 is formed by a recess 48 formed in the crankcase 4 and a cover member 50 attached to the crankcase 4. Specifically, as shown in FIG. 5, the cover member 50 is detachably attached to the crankcase 4 via a seal member 52 (FIG. 7) by a plurality of bolts 54. The seal member 52 is, for example, a gasket made of graphite. However, the seal member 52 is not limited thereto.

[0041] As shown in FIG. 9, the breather chamber 40 of this embodiment has four rooms 61, 62, 63, 64 partitioned by a plurality of partition walls 56. The structure of each room 61, 62, 63, 64 of the breather chamber 40 of this embodiment will be described with reference to FIGS. 6 to 9. FIG. 6 shows a state in which the cover member 50 and the seal member 52 are removed, FIG. 7 shows a state in which only the cover member 50 is removed, FIG. 8 shows the back surface of the cover member 50, and FIG. 9 is a perspective view schematically showing the flow of the fluid F in the breather chamber 40.

[0042] As shown in FIG. 6, a first partition wall 56a that partitions the internal space 48a of the recess 48 is formed in the breather chamber 40. The first partition wall 56a is a wall that extends in the vertical direction VD from the upper end to the lower end of the recess 48 of the breather chamber 40 and divides the internal space 48a of the recess 48 in the engine width direction WD. In the following description, of the portions of the internal space 48a of the recess 48 partitioned by the first partition wall 56a, the portion on one side in the engine width direction WD is defined as the first portion 48a1, and the portion on the other side is defined as the second portion 48a2.

[0043] Further, a second partition wall 56b that vertically partitions the first portion 48a1 is formed in the recess 48 of the breather chamber 40. The second partition wall 56b is a wall that extends in the engine width direction WD from the first partition wall 56a to the outer wall of the recess 48 and divides the first portion 48a1 in the vertical direction VD. In the following description, of the portions of the first portion 48a1 partitioned by the second partition wall 56b, the upper portion is defined as the third portion 48a3, and the lower portion is defined as the fourth portion 48a4.

[0044] As shown in FIG. 7, a gasket 52, which is a kind of sealing member, is interposed between the end faces of the outer peripheral wall of the recess 48 of the breather chamber 40, the end face of the first partition wall 56a, and the end face of the second partition wall 56b. In the present embodiment, the sealing member 52 closes the third portion 48a3 of the internal space 48a of the recess 48 to the outside, that is, from the intake side in the orthogonal direction PD. That is, the portion of the sealing member 52 that closes the third portion 48a3 from the outside constitutes the third partition wall 56c. Thus, in the present embodiment, one of the partition walls 56 is constituted by the sealing member 52.

[0045] As shown in FIG. 8, a fourth partition wall 56d is formed in a portion of the back surface of the cover member 50 corresponding to the first partition wall 56a, and a fifth partition wall 56e is formed in a portion corresponding to the second partition wall 56b.

[0046] The fourth partition wall 56d divides the internal space 50a of the cover member 50 into a first portion 50a1 on one side (the left side in FIG. 8) in the engine width direction WD and a second portion 50a2 on the other side (the right side in FIG. 8). The fifth partition wall 56e divides the first portion 50a1 of the internal space 50a of the cover member 50 into an upper third portion 50a3 and a lower fourth portion 50a4.

[0047] A gas outlet 58 for leading out the gas components in the breather chamber 54 to the outside is formed in the cover member 50. In the present embodiment, the gas outlet 58 is provided slightly below the middle portion in the vertical direction of the cover member 50. The breather outlet passage 42 (FIG. 2) is connected to the gas outlet 58.

[0048] Further, a baffle plate 60 is formed on the inner surface, that is, the back surface of the cover member 50. The baffle plate 60 protrudes from the inner surface of the cover member 50 toward the inside of the breather chamber 40 and covers at least a part of the circumferential direction of the gas outlet 58. In the present embodiment, the baffle plate 60 has an arc shape and covers the upper part of the gas outlet 58.

[0049] As shown in Fig. 9, with the cover member 50 attached to the crankcase 4, the second portion 48a2 of the internal space 48a of the recess 48 communicates with the second portion 50a2 of the internal space 50a of the cover member 50.

[0050] Similarly, with the cover member 50 attached to the crankcase 4, the third portion 48a3 of the internal space 48a of the recess 48 communicates with the third portion 50a3 of the internal space 50a of the cover member 50. However, the third portion 48a3 of the internal space 48a of the recess 48 and the third portion 50a3 of the internal space 50a of the cover member 50 are partitioned by the third partition wall 56c of the seal member 52.

[0051] Furthermore, with the cover member 50 attached to the crankcase 4, the fourth portion 48a4 of the internal space 48a of the recess 48 communicates with the fourth portion 50a4 of the internal space 50a of the cover member 50.

[0052] In this way, the first room 61 of the breather chamber 40 is formed by the fourth portion 48a4 of the internal space 48a of the recess 48 and the fourth portion 50a4 of the internal space 50a of the cover member 50. Also, the second room 62 of the breather chamber 40 is formed by the third portion 50a3 of the internal space 50a of the cover member 50, and the third room 63 of the breather chamber 40 is formed by the third portion 48a3 of the internal space 48a of the recess 48. Furthermore, the fourth room 64 of the breather chamber 40 is formed by the second portion 48a2 of the internal space 48a of the recess 48 and the second portion 50a2 of the internal space 50a of the cover member 50.

[0053] The fluid flows in the order of the first room 61, the second room 62, the third room 63, and the fourth room 64. The rooms adjacent in the flow direction communicate with each other through the communication holes 70 formed in the partition wall 56. The breather outlet 38b of the breather introduction passage 38 opens at the exhaust side portion in the orthogonal direction PD on the bottom wall of the first room 61. As shown in Fig. 8, the first communication hole 71 is formed in the fifth partition wall 56e of the cover member 50. The first room 61 and the second room 62 in Fig. 9 communicate with each other through the first communication hole 71.

[0054] As shown in FIG. 7, a second communication hole 72 is formed in the third partition wall 56c of the seal member 52. The second room 62 and the third room 63 in FIG. 9 communicate with each other through the second communication hole 72. As shown in FIG. 6, a third communication hole 73 is formed in a portion of the first partition wall 56a that constitutes the third room 63. The third room 63 and the fourth room 64 in FIG. 9 communicate with each other through the third communication hole 73.

[0055] Next, the flow of the fluid F in the breather chamber 40 of the present embodiment will be described. The fluid F that has flowed into the first room 61 from the breather outlet 38b of the breather introduction passage 38 flows in the first room 61 toward the intake side in the orthogonal direction PD, then changes its direction upward and flows, and flows into the second room 62 through the first communication hole 71.

[0056] The fluid F that has flowed into the second room 62 flows in the second room 62 toward the exhaust side in the orthogonal direction PD and flows into the third room 63 through the second communication hole 72. The fluid F that has flowed into the third room 63 flows in the third room 62 toward the exhaust side in the orthogonal direction PD, then changes its direction to the width direction WD and flows, and flows into the fourth room 64 through the third communication hole 73. The fluid F that has flowed into the fourth room 64 changes its direction from the width direction WD downward and flows.

[0057] In this way, by repeating the inflow and outflow to each of the rooms 61, 62, 63, 64 while changing the flow direction, the fluid F collides with the partition wall 56 and expands and contracts, and gas-liquid separation is promoted. In the fourth room 64, the gas component Fg of the separated fluid F is sent from the gas outlet 58 through the breather lead-out passage 42 to the intake system of the engine E. On the other hand, the liquid component Fl of the separated fluid F is returned to the oil pan 14 from the return passage 44. At this time, the baffle plate 60 above the gas outlet 58 prevents the liquid component Fl from flowing into the gas outlet 58.

[0058] An inlet 44a of a return passage 44 opens on the other side portion in the engine width direction WD of the bottom wall of the fourth chamber 64. The return passage 44 extends downward from the breather chamber 40, and as shown in FIG. 2, an oil return port 44b which is an outlet opens into the oil pan 14. A liquid component Fl of the fluid F is returned to the oil pan 14 through the return passage 44.

[0059] The return passage 44 of the present embodiment is an internal passage formed inside the crankcase 4, similar to the breather introduction passage 38. The return passage 44 extends in the vertical direction, and the oil return port 44b at the lower end opens into a liquid collection space SP of the oil pan 14.

[0060] The oil return port 44b opens at a position closer to the suction port 30b of the scavenge pump 30 than the breather intake port 38a in the liquid collection space SP. In the present embodiment, a part (lower end portion) of the return passage 44 is formed in the wall of the oil pan 14 and extends downward to the vicinity of the suction port 30b of the scavenge pump 30. In the present embodiment, the oil return port 44b opens toward the suction port 30b of the scavenge pump 30.

[0061] According to the above configuration, since the oil collected in the oil pan 14 is discharged by the scavenge pump 30, the liquid level of the oil in the oil pan 14 does not rise. Therefore, it is possible to prevent the liquid component of the oil in the oil pan 14 from going from the breather intake port 38a toward the breather chamber 40, and the gas-liquid separation effect of the fluid F is improved. In particular, since the breather intake port 38a is arranged at a position facing the liquid collection space SP of the oil pan 14 from above, that is, at a high position inside the oil pan 14, it is hardly affected by the liquid level of the oil. As a result, it becomes difficult for the liquid component to be taken in from the breather intake port 38a, and the gas-liquid separation effect of the fluid F is improved.

[0062] In this embodiment, the breather intake port 38a is formed at a position higher than the suction port 30b of the scavenge pump 30. According to this configuration, due to the suction by the scavenge pump 30, it is easy to dispose the breather intake port 38a above the oil liquid level. Therefore, it is possible to prevent oil from flowing from the breather intake port 38a toward the breather chamber 40. As a result, the gas-liquid separation effect of the fluid F is improved.

[0063] In this embodiment, the breather intake port 38a is formed at a portion above the joint surface 45 with the oil pan 14 in the crankcase 4. According to this configuration, it is easy to dispose the breather intake port 38a above the oil liquid level. Thereby, even when the attitude of the engine changes, it is possible to prevent oil from flowing from the breather intake port 38a toward the breather chamber 40. As a result, the gas-liquid separation effect of the fluid F is improved.

[0064] In this embodiment, the breather intake port 38a is disposed closer to the wall surface of the oil pan 14 in the axial direction of the crankshaft 2, that is, in the engine width direction WD, than the scavenge pump 30. According to this configuration, it is easy to separate the scavenge pump 30 from the breather intake port 38a, and it is possible to prevent oil droplets generated during suction from entering the breather intake port 38a. As a result, the gas-liquid separation effect of the fluid F is improved.

[0065] In this embodiment, the oil pan 14 has a bottom wall 14a that constitutes the deepest part and an inclined wall 14b that extends upward as it moves away from the bottom wall 14a in the horizontal direction, and the breather intake port 38a is disposed above the inclined wall 14b. According to this configuration, since it is difficult for oil to accumulate on the inclined wall 14b, it is possible to prevent oil from flowing from the breather intake port 38a toward the breather chamber 40. As a result, the gas-liquid separation effect of the fluid F is improved.

[0066] In the present embodiment, as shown in FIG. 3, a vertical wall 46 is provided to prevent oil from flowing toward the breather intake port 38a. According to this configuration, it is possible to prevent oil from entering the breather chamber 40 from the breather intake port 38a. As a result, the gas-liquid separation effect of the fluid F is improved.

[0067] In the present embodiment, the vertical wall 46 extends in a direction intersecting with the axial direction of the crankshaft 2, that is, in the engine width direction WD. According to this configuration, even when the oil in the oil pan 14 moves in the axial direction of the crankshaft 2 due to a change in posture, the vertical wall 46 can prevent the oil from entering the breather intake port 38a. As a result, the gas-liquid separation effect of the fluid F is improved.

[0068] In the present embodiment, the vertical wall 46 is disposed between the vertical passage 27 communicating with the crank chamber 5 and the breather intake port 38a. According to this configuration, the vertical wall 46 can prevent the oil flowing downward through the vertical passage 27 from entering the breather intake port 38a. As a result, the gas-liquid separation effect of the fluid F is improved.

[0069] In the present embodiment, the breather chamber 40 is provided on the intake port side in the orthogonal direction PD in the crankcase 2, and the breather intake port 38a is disposed closer to the wall surface on the intake port side with respect to the orthogonal direction PD. According to this configuration, while the breather chamber 40 is disposed on the relatively low-temperature intake side from the breather intake port 38a, the passage from the breather intake port 38a to the breather chamber 40 can be shortened.

[0070] In the present embodiment, the breather intake port 38a is formed in the lower crankcase lower 4a, and the breather chamber 40 is formed in the upper crankcase upper 4b. According to this configuration, the breather introduction passage 38 extending from the crankcase lower 4a to the crankcase upper 4b is formed to be long, and the fluid is also gas-liquid separated in the breather introduction passage 38. As a result, the gas-liquid separation effect is improved. Further, since the breather chamber 40 is separated from the oil pan 14, it is possible to cope with the case where the posture of the engine E changes and the liquid level inclines.

[0071] In the present embodiment, the breather chamber 40 is formed by a recess 48 formed in the crankcase 4 and a cover member 50 attached to the crankcase 4. According to this configuration, the volume of the breather chamber 40 can be adjusted by changing the shape of the cover member 50.

[0072] In the present embodiment, a gas outlet 58 for leading out the gas component Fg in the breather chamber 40 to the outside is formed in the cover member 50, and a baffle plate 60 covering at least a part of the circumferential direction of the gas outlet 58 shown in FIG. 8 is formed on the inner surface of the cover member 50. According to this configuration, it is possible to prevent the liquid component Fl of the fluid F separated into gas and liquid in the breather chamber 40 from heading toward the gas outlet 58.

[0073] In the present embodiment, the cover member 50 shown in FIG. 5 is attached to the crankcase 4 via a seal member 52, and the breather chamber 40 has a partition wall 56 that partitions the breather chamber 40 into a plurality of chambers 61 to 64 and a communication hole 70 formed in the partition wall 56, and at least one of the partition walls 56 is constituted by the seal member 52. According to this configuration, since the seal member 52 can be used as the partition wall 56, the number of partition walls 56 provided in the crankcase 4 can be reduced, and the structure becomes simple.

[0074] In the present embodiment, an oil return port 44b for returning the liquid component Fl in the breather chamber 40 to the inside of the oil pan 14 opens at a position closer to the suction port 30b of the scavenge pump 30 than the breather intake port 38a. According to this configuration, since the liquid component Fl led out from the oil return port 44b is sucked from the suction port 30b of the scavenge pump 30, the liquid in the oil pan 14 can be efficiently discharged.

[0075] The engine of the present disclosure is suitably mounted on a moving body such as an aircraft or a vehicle. Further, the engine of the present disclosure is suitably mounted on an off-road vehicle such as a four-wheel buggy (all-terrain vehicle), a utility vehicle, or a recreational vehicle, for example.

[0076] In this embodiment, the breather introduction passage 38 is an internal passage. However, if the breather intake port 38a is formed at a position facing the liquid collection space SP from above, it may be an external passage, that is, a separate pipe. In the case of an external passage, one end of the pipe is arranged at a position facing the liquid collection space SP from above, and the other end communicates with the breather chamber 40 through the outside of the engine.

[0077] The engine of the present disclosure includes the following aspects 1 to 16. [Aspect 1] A crankshaft that converts the reciprocating motion of the piston into a rotational motion, A crankcase that supports the crankshaft, A cylinder that protrudes from one side of the crankcase in the piston reciprocating direction, An oil pan that is attached below the crankcase and forms a liquid collection space for collecting the oil that lubricates the lubricated parts in the crankcase, A scavenge pump that sucks oil from the liquid collection space and discharges it to the oil tank, Comprising, An engine in which a breather intake port is formed at a position facing the liquid collection space from above. [Aspect 2] In the engine according to Aspect 1, the breather intake port is formed at a position higher than the suction port of the scavenge pump. [Aspect 3] In the engine according to Aspect 1 or 2, the breather intake port is formed at a portion above the joint surface of the crankcase with the oil pan. [Aspect 4] In the engine according to any one of Aspects 1 to 3, the breather intake port is arranged closer to the wall surface of the oil pan in the axial direction of the crankshaft than the scavenge pump. [Aspect 5] In the engine according to any one of Aspects 1 to 4, the oil pan has a bottom wall that constitutes the deepest part and an inclined wall that extends upward as it moves away from the bottom wall in the horizontal direction. An engine in which the breather intake port is arranged to face the inclined wall. [Aspect 6] In the engine according to any one of Aspects 1 to 5, an engine provided with a vertical wall that prevents oil from flowing toward the breather intake port. [Aspect 7] In the engine according to Aspect 6, the vertical wall extends in a direction intersecting the axial direction of the crankshaft. [Aspect 8] In the engine according to Aspect 6 or 7, the vertical wall is arranged between an upper and lower passage communicating with the crank chamber in which the crankshaft is arranged and the breather intake port. [Aspect 9] In the engine according to any one of Aspects 1 to 8, an intake port is arranged on one side in the orthogonal direction that is orthogonal to both the axial direction and the vertical direction of the crankshaft, and an exhaust port is arranged on the other side, a breather chamber to which the fluid taken in from the breather intake port is supplied is provided on the intake port side in the orthogonal direction in the crankcase, the breather intake port is arranged closer to the wall surface on the intake port side in the orthogonal direction. [Aspect 10] In the engine according to any one of Aspects 1 to 9, the crankcase has a first case half to which the cylinder is connected and a second case half to which the oil pan is connected, the breather intake port is formed in the second case half, a breather chamber to which the fluid taken in from the breather intake port is supplied is formed in the first case half. [Aspect 11] In the engine according to any one of Aspects 1 to 10, a breather chamber to which the fluid taken in from the breather intake port is supplied is formed in the crankcase, the breather chamber is formed by a recess formed in the crankcase and a cover member attached to the crankcase. [Aspect 12] In the engine according to Aspect 11, a gas outlet for leading out the gas components in the breather chamber to the outside is formed in the cover member, and a baffle plate covering at least a part of the circumferential direction of the gas outlet is formed on the inner surface of the cover member. [Aspect 13] In the engine according to claim 11 or 12, the cover member is attached to the crankcase via a seal member, the breather chamber has a partition wall partitioning the breather chamber into a plurality of rooms and a communication hole formed in the partition wall, and at least one of the partition walls is constituted by the seal member. [Aspect 14] In the engine according to any one of Aspects 1 to 13, a breather chamber to which the fluid taken in from the breather intake port is supplied is formed in the crankcase, and an oil return port for returning the liquid components in the breather chamber to the inside of the oil pan opens at a position closer to the suction port of the scavenge pump than the breather intake port. [Aspect 15] A moving body including the engine according to any one of Aspects 1 to 14. [Aspect 16] An off-road vehicle including the engine according to any one of Aspects 1 to 14.

[0078] The present disclosure is not limited to the above forms, and various additions, changes, or deletions are possible without departing from the gist of the present disclosure. For example, the engine E in the above embodiment can also be applied to saddle-riding type vehicles such as motorcycles, three-wheeled vehicles, and four-wheel buggies (all-terrain vehicles). The engine E may be used for an outboard motor or as a propulsion source for an aircraft. In addition, the engine E may be used as a propulsion source for a four-wheel vehicle or a small speedboat. The number of cylinders is not limited to six cylinders, and it may be less than six cylinders or seven cylinders or more. A supercharger such as a turbocharger or a supercharger may be provided for the engine E. Therefore, such things are also included within the scope of the present disclosure.

Explanation of Signs

[0079] 2 Crankshaft 3 Piston 4 Crankcase 4a Second case half (crankcase lower) 4b First case half (crankcase upper) 5 Crank chamber 6 Cylinder 14 Oil pan 14a Bottom wall (deepest part) 14b Inclined wall 16 Intake port 18 Exhaust port 27 Upper and lower passage 28 Oil tank 30 Scavenge pump 30b Suction port of scavenge pump 38a Breather intake port 40 Breather chamber 45 Joint surface between crankcase and oil pan 46 Vertical wall 48 Recess 50 Cover member 52 Seal member 56 Partition wall 58 Gas outlet 60 Baffle plate 61~64 Rooms 70 Communication hole E Engine SP Liquid collection space

Claims

1. A crankshaft that converts the reciprocating motion of a piston into rotational motion, a crankcase that supports the crankshaft, a cylinder that protrudes from one side of the crankcase in the piston reciprocating direction, an oil pan that is attached below the crankcase and forms a liquid collection space for collecting oil that lubricates the lubricated parts in the crankcase, a scavenge pump that sucks oil from the liquid collection space and discharges it to an oil tank, and comprising an engine in which a breather intake port is formed at a position facing the liquid collection space from above.

2. The engine according to claim 1, wherein the breather intake port is formed at a position higher than the suction port of the scavenge pump.

3. The engine according to claim 1 or 2, wherein the breather intake port is formed at a part above the mating surface of the crankcase with the oil pan.

4. The engine according to claim 1 or 2, wherein the breather intake port is arranged closer to the wall surface of the oil pan in the axial direction of the crankshaft than the scavenge pump.

5. The engine according to claim 1 or 2, wherein the oil pan has a bottom wall that constitutes the deepest part and an inclined wall that extends upward as it moves away from the bottom wall in the horizontal direction, and the breather intake port is arranged so as to face the inclined wall.

6. The engine according to claim 1 or 2, wherein a standing wall is provided to prevent oil from flowing toward the breather intake port.

7. The engine according to claim 6, wherein the standing wall extends in a direction intersecting the axial direction of the crankshaft.

8. The engine according to claim 6, wherein the standing wall is arranged between an upper and lower passage communicating with the crank chamber in which the crankshaft is arranged and the breather intake port.

9. In the engine according to claim 1 or 2, an intake port is arranged on one side in the orthogonal direction that is orthogonal to both the axial direction and the vertical direction of the crankshaft, and an exhaust port is arranged on the other side, and a breather chamber to which the fluid taken in from the breather intake port is supplied is provided on the intake port side in the orthogonal direction in the crankcase. The breather intake port is arranged closer to the wall surface on the intake port side with respect to the orthogonal direction, for an engine.

10. In the engine according to claim 1 or 2, the crankcase has a first case half to which the cylinder is connected and a second case half to which the oil pan is connected, the breather intake port is formed in the second case half, and a breather chamber to which the fluid taken in from the breather intake port is supplied is formed in the first case half, for an engine.

11. In the engine according to claim 1 or 2, a breather chamber to which the fluid taken in from the breather intake port is supplied is formed in the crankcase, and the breather chamber is formed by a recess formed in the crankcase and a cover member attached to the crankcase, for an engine.

12. In the engine according to claim 11, a gas outlet for leading out the gas component in the breather chamber to the outside is formed in the cover member, and a baffle plate covering at least a part of the circumferential direction of the gas outlet is formed on the inner surface of the cover member, for an engine.

13. In the engine according to claim 11, the cover member is attached to the crankcase via a seal member, the breather chamber has a partition wall partitioning the breather chamber into a plurality of rooms and a communication hole formed in the partition wall, and at least one of the partition walls is constituted by the seal member, for an engine.

14. In the engine according to claim 1 or 2, a breather chamber to which the fluid taken in from the breather intake port is supplied is formed in the crankcase, and an oil return port for returning the liquid component in the breather chamber to the inside of the oil pan opens at a position closer to the suction port of the scavenge pump than the breather intake port, for an engine.

15. An engine includes a crankshaft that converts the reciprocating motion of a piston into a rotational motion, a crankcase that supports the crankshaft, a cylinder that protrudes from one side of the crankcase in the piston reciprocating direction, an oil pan that is attached below the crankcase and forms a liquid collection space for collecting oil that lubricates lubricated parts in the crankcase, and a scavenge pump that sucks oil from the liquid collection space and discharges it to an oil tank, a moving body in which a breather intake port is formed at a position facing the liquid collection space from above.

16. The mobile body according to claim 15, wherein the mobile body is an offloading vehicle.

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