Engine system

Abstract

To provide an engine system capable of suppressing reduction in a service life of an oil cooler.SOLUTION: An engine system SY includes: a scavenging pump 30 for sucking and discharging oil O from inside of an oil pan 14 of an engine E; an oil tank 28 that stores the oil O discharged by the scavenging pump 30; an oil cooler 40 that cools the oil O derived from the oil tank 28; and a feed pump 32 for supplying the oil O derived from the oil cooler 40 to a lubricated portion of the engine E.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an engine system with a dry sump lubrication method.

Background Art

[0002] As a vehicle drive source, an engine with a dry sump lubrication method having a scavenge pump that sucks oil from inside the oil pan and discharges it to an oil tank may be used (for example, Patent Document 1). The oil stored in the oil tank is pumped to the lubricated parts of the engine by a feed pump. Also, before being pumped by the feed pump after being discharged from the oil pan by the scavenge pump, the oil is cooled by an oil cooler.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such an engine, if an oil cooler is arranged downstream of the scavenge pump and upstream of the oil tank, air from the scavenge pump may enter the oil cooler, which may affect the life of the oil cooler.

[0005] The disclosure of the present application provides an engine system capable of suppressing a decrease in the life of the oil cooler.

Means for Solving the Problems

[0006] The engine system of the present disclosure includes a scavenge pump that sucks and discharges oil from inside the oil pan of the engine, an oil tank that stores the oil discharged by the scavenge pump, an oil cooler that cools the oil derived from the oil tank, and a feed pump that supplies the oil derived from the oil cooler to lubricated parts of the engine.

Advantages of the Invention

[0007] According to the engine system of the present disclosure, an oil tank is arranged on the downstream side of the scavenge pump, and an oil cooler is arranged on the downstream side of the oil tank. Thereby, the air from the scavenge pump escapes in the oil tank, so that the air entrainment in the oil cooler can be avoided. As a result, it is possible to suppress a decrease in the life of the oil cooler.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present disclosure will be described with reference to FIGS. 1 to 3. The engine E of this 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 is applicable, for example, as a driving source for ships and also as a driving source for vehicles such as motorcycles and four-wheel 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 this 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 for example, it may be four cylinders. Further, the engine E of this embodiment is a gasoline engine, but the fuel is not limited to gasoline. The crankshaft 2 changes the reciprocating motion of the piston 3 into a rotational motion.

[0012] The engine E has a crankcase 4 that supports the 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. 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 this 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 integrated structure of the crankcase upper 4b and the cylinder 6 is referred to as the 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. In the cam chamber, a valve operating mechanism for opening and closing the intake and exhaust valves in conjunction with the rotation of the crankshaft 2 is arranged.

[0015] The engine E further has an oil pan 14 connected to the lower end of the crankcase 4. Engine oil for lubricating the lubricated parts of the engine E is stored in the oil pan 14.

[0016] The intake port 16 opens on one side (the right side in FIG. 1) of the cylinder head 8 in the orthogonal direction PD, and the 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".

[0017] 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.

[0018] 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 fuel-air mixture. The fuel-air 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.

[0019] Figure 2 is a front view of the engine E as seen from the intake side in the orthogonal direction PD. As shown in the figure, the output shaft 25 and the reduction mechanism 26 are provided on one side (the right side in Figure 2) in the width direction WD of the engine E. The rotational force of the crankshaft 2 is reduced by the reduction mechanism 26 and transmitted to the output shaft 25. A rotating body RB such as an aircraft propeller, vehicle wheels, turbine rotor blades, compressor impellers, or blower fans is attached to the output shaft 25 directly or via a power transmission member.

[0020] The engine E of the present disclosure is an engine with a dry sump lubrication system having a scavenge pump 30 that sucks oil O from inside the oil pan 14 and discharges it to the oil tank 28. In the present embodiment, the engine E and the oil tank 28 constitute an engine system SY with a dry sump lubrication system. The oil O 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 O after lubricating the lubricated parts is returned to the oil pan 14.

[0021] In the following description, "upstream" and "downstream" refer to "upstream" and "downstream" in the flow direction of the oil O, respectively.

[0022] The oil tank 28 stores the oil O discharged by the scavenge pump 30. In the present embodiment, the oil tank 28 is provided outside the engine E, that is, separated from the engine E. The oil tank 28 is, for example, made of metal. However, the material of the oil tank 28 is not limited to this.

[0023] In this embodiment, the oil tank 28 is disposed on the output shaft side (the right side in FIG. 2) in the engine width direction WD. That is, the oil tank 28 is provided near the rotating body RM attached to the output shaft 25. As a result, the air flow generated by the rotation of the rotating body RM heads toward the oil tank 28, taking away the heat of the oil tank 28 and the oil O inside it. Thus, in this embodiment, the rotating body RM constitutes a cooling mechanism CM that supplies cooling air to the oil tank 28.

[0024] The cooling mechanism CM is not limited to the rotating body RM attached to the output shaft 25. For example, when the engine E is mounted on a moving body such as an aircraft or a vehicle, the running wind may be used. Further, a blower may be provided separately as the cooling mechanism CM. The cooling mechanism CM may not be provided.

[0025] As described above, the scavenge pump 30 sucks the oil O from inside the oil pan 14 of the engine E and discharges it to the outside of the oil pan 14. In this embodiment, the scavenge pump 30 is disposed inside the oil pan 14.

[0026] In this 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.

[0027] The feed pump 32 pressurizes the oil O stored in the oil tank 28 and pumps it to the lubricated parts of the engine E. The oil O pumped by the feed pump 32 is first supplied to the main oil gallery 36. The main oil gallery 36 is the largest-diameter passage among the passages inside the engine through which the oil O pressurized by the feed pump 32 flows, and into which the oil from the feed pump 32 first flows. The main oil gallery 36 is also the passage with the highest pressure among the passages inside the engine. As shown in FIG. 1, in this embodiment, the main oil gallery 36 is provided on the exhaust side. An oil jet that injects the oil O behind the piston 3 is provided in the main oil gallery 36.

[0028] As shown in FIG. 2, in the present embodiment, the feed pump 32 is also disposed in the oil pan 14. Specifically, the feed pump 32 is disposed on the other side (the left side in FIG. 2) in the width direction WD of the engine E inside the oil pan 14. That is, the scavenge pump 30 and the feed pump 32 are arranged side by side in the engine width direction WD.

[0029] In the present 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.

[0030] In the present 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 shaft 30a of the scavenge pump 30 and the rotation shaft 32a of the feed pump 32 are coaxially arranged, and both rotation shafts 30a, 32a are connected. The power transmission member 34 is spanned over the rotation shaft 32a of the feed pump 32, and the rotational force of the crankshaft 2 is transmitted to the rotation shaft 32a of the feed pump 32 and the rotation shaft 30a of the scavenge pump 30 connected thereto via the power transmission member 34.

[0031] The engine E of the present disclosure includes an oil cooler 40 that cools the oil O. In the oil cooler 40 of the present embodiment, the oil O is cooled by heat exchange with the cooling water of the engine E. Specifically, a cooling water inlet 38 is formed on the intake side surface in the orthogonal direction PD in the crankcase 4 of the engine E, and an inlet fitting 42 attached to the cooling water inlet 38 and the oil cooler 40 are connected by a bypass passage 44. A part of the engine cooling water is supplied to the oil cooler 40 through this bypass passage 44. However, the form of the oil cooler 40 is not limited to this, and it may be an air-cooled oil cooler, or a structure in which the oil is cooled by a coolant dedicated to oil.

[0032] In the present embodiment, the oil cooler 40 is disposed on the intake side in the orthogonal direction PD in the crankcase 4 of the engine E. Specifically, with respect to the orthogonal direction PD, the orthogonal direction center of the oil cooler 40 is located on the intake side of the orthogonal direction center of the crankcase 4. Thereby, it is possible to avoid the influence of the heat of the exhaust gas and increase the cooling efficiency of the oil cooler 40, and the bypass passage 44 can be made compact.

[0033] The oil cooler 40 is provided on the downstream side of the oil tank 28 and on the upstream side of the feed pump 32. That is, in the present embodiment, the oil O flows in the order of the scavenge pump 30, the oil tank 28, the oil cooler 40, and the feed pump 32. That is, the oil cooler 40 cools the oil O led out from the oil tank 28.

[0034] In the present embodiment, the oil cooler 40 is attached to the crankcase 4 of the engine E via the adapter 46. Specifically, the adapter 46 is detachably attached to the crankcase 4 by a fastening member such as a bolt, and the oil cooler 40 is detachably attached to the adapter 46 by a fastening member such as a bolt.

[0035] The adapter 46 is interposed between the crankcase 4 and the oil cooler 40, and a passage for the oil O is formed inside. Specifically, as shown in FIG. 3, a cooler bypass passage 48 and a cooler inlet passage 50 are formed in the adapter 46. The cooler bypass passage 48 allows the oil O supplied from the scavenge pump 30 to flow toward the oil tank 28. That is, the oil O in the cooler bypass passage 48 does not pass through the oil cooler 40. The cooler inlet passage 50 allows the oil O supplied from the oil tank 28 to flow toward the oil cooler 40.

[0036] Next, with reference to FIGS. 2 and 3, the passage of the oil O and the flow of the oil O in the engine system SY of the present embodiment will be described. In FIG. 3, the broken line indicates an internal passage, that is, a passage that cannot be visually recognized from the outside, and the solid line indicates an external passage that can be visually recognized from the outside.

[0037] When the engine E shown in FIG. 2 starts, the scavenge pump 30 and the feed pump 32 are driven in conjunction with the rotation of the crankshaft 2. The oil O in the oil pan 14 is recovered by the scavenge pump 30 and discharged from the oil pan 14.

[0038] The oil O discharged from the oil pan 14 by the scavenge pump 30 is supplied to the adapter 46 through the first passage 51. The first passage 51 is an internal passage formed inside the crankcase 4. The first passage 51 extends vertically inside the crankcase 4, the lower end is connected to the scavenge pump 30, and the upper end communicates with the cooler bypass passage 48 of the adapter 46.

[0039] The oil O flowing into the cooler bypass passage 48 flows through the cooler bypass passage 48 and is supplied to the second passage 52. The second passage 52 is an internal passage formed inside the crankcase 4. The second passage 52 extends in the engine width direction WD inside the crankcase 4, the upstream end communicates with the cooler bypass passage 48, and the downstream end communicates with the third passage 53 of the adapter 46 shown in FIG. 3.

[0040] The oil O flowing into the third passage 53 flows through the third passage 53 and is supplied to the oil tank 28. The third passage 53 is an external passage with the pipe exposed to the outside. The third passage 53 extends from the crankcase 4 to the oil tank 28 arranged apart from the engine E, the upstream end communicates with the second passage 52, and the downstream end is connected to the oil tank 28.

[0041] The oil O flowing into the oil tank 28 is stored in the oil tank 28. The oil O in the oil tank 28 is supplied to the adapter 46 through the fourth passage 54. The fourth passage 54 is an external passage with the pipe exposed to the outside. The fourth passage 54 extends from the oil tank 28 to the crankcase 4, the upstream end is connected to the oil tank 28 to the second passage 52, and the downstream end communicates with the cooler inlet passage 50 of the adapter 46 shown in FIG. 3.

[0042] The oil O flowing into the cooler inlet passage 50 flows through the cooler inlet passage 50 and is supplied to the oil cooler 40. When passing through the oil cooler 40, the oil O is cooled by heat exchange with the cooling water. The oil O cooled by the oil cooler 40 flows into the fifth passage 55.

[0043] The oil O flowing into the fifth passage 55 flows through the fifth passage 55 and is supplied to the feed pump 32. The fifth passage 55 is an external passage with the piping exposed to the outside. The upstream end of the fifth passage 55 is connected to the oil cooler 40, and the downstream end is connected to the feed pump 32.

[0044] The oil O supplied to the feed pump 32 is pressurized by the feed pump 32 and supplied to the main oil gallery 36 through the sixth passage 56. The sixth passage 56 is an internal passage formed inside the crankcase 4. The sixth passage 56 extends vertically inside the crankcase 4, with the upstream end connected to the feed pump 32 and the downstream end communicating with the main oil gallery 36.

[0045] The oil O supplied to the main oil gallery 36 is pumped to the lubricated parts of the engine E. After lubricating the lubricated parts, the oil O returns to the oil pan 14 under its own weight.

[0046] Figure 4 is a schematic diagram showing the flow of oil in the engine system of the comparative example. In the example of Figure 4, the oil discharged from the oil pan 14 by the scavenge pump 30 is supplied to the oil cooler 40 through the first passage 101. After being cooled by the oil cooler 40, the oil is supplied to the oil tank 28 through the second passage 102 and the third passage 103. The oil stored in the oil tank 28 is supplied to the feed pump 32 through the fourth passage 104. The oil pressurized by the feed pump 32 is supplied to the main oil gallery 36. Also in Figure 4, the dashed line indicates the internal passage, and the solid line indicates the external passage.

[0047] In the example of FIG. 4, since the oil cooler 40 is arranged downstream of the scavenge pump 30 and upstream of the oil tank 28, air from the scavenge pump 30 may be drawn into the oil cooler 40, which may affect the service life of the oil cooler 40.

[0048] According to the above configuration, as shown in FIG. 2, the oil tank 40 is arranged on the downstream side of the scavenge pump 30, and the oil cooler 28 is arranged on the downstream side of the oil tank 40. Thereby, since the air from the scavenge pump 30 escapes in the oil tank 28, the air being drawn into the oil cooler 40 can be avoided. As a result, it is possible to suppress a decrease in the service life of the oil cooler 40.

[0049] In order to prevent the air from being drawn into the scavenge pump 30, it is also conceivable to arrange the oil cooler 40 on the downstream side of the feed pump 32. In the above embodiment, as shown in FIG. 1, the main gallery 36 to which the feed pump 32 supplies the oil O is arranged on the exhaust side in the orthogonal direction PD in the crankcase 4. Therefore, in order to arrange the oil cooler 40 on the downstream side of the feed pump 32, it is necessary to arrange the oil cooler 40 on the exhaust side.

[0050] However, in the above embodiment, the inlet fitting 42 of the cooling water inlet 38 for supplying the cooling water to the oil cooler 40 in FIG. 2 is arranged on the intake side. For this reason, if the oil cooler 40 is arranged on the exhaust side, the cooling water piping becomes complicated, which is not preferable. In the above embodiment, while arranging the oil cooler 40 on the intake side to simplify the cooling water piping, the air being drawn into the oil cooler 40 is avoided to prevent a decrease in the service life of the oil cooler 40.

[0051] In addition, since the temperature of the intake side is lower than that of the exhaust side, arranging the oil cooler 40 on the intake side suppresses the temperature rise of the oil O and the cooling water, so that the cooling effect of the oil cooler 40 is improved.

[0052] In this embodiment, the oil tank 28 is disposed outside the engine E. According to this configuration, heat from the engine E can be prevented from being transmitted to the oil tank 28, and an increase in the temperature of the oil O in the oil tank 28 can be avoided. Further, the oil O is cooled by radiation in the passage toward the oil tank 28 and in the oil tank 28. Thus, since the oil O whose temperature has decreased via the oil tank 28 is sent to the oil cooler 40, the oil O can be effectively cooled by the oil cooler 40. Thereby, miniaturization of the oil cooler 40 can also be achieved.

[0053] In this embodiment, further, a cooling mechanism CM for supplying cooling air to the oil tank 28 is provided. In the above embodiment, as the cooling mechanism CM, it is a rotating body RB attached to the output shaft 25 of the engine E. According to this configuration, the oil O in the oil tank 28 can be effectively cooled. Since the oil O cooled by the oil tank 28 is sent to the oil cooler 40, the oil O can be more effectively cooled by the oil cooler 40. Thereby, miniaturization of the oil cooler 40 can also be achieved.

[0054] In this embodiment, the oil cooler 40 is attached to the crankcase 4 via an adapter 46. Further, the adapter 40 has a cooler bypass passage 48 that allows the oil O supplied from the scavenge pump 30 to flow toward the oil tank 28, and a cooler inlet passage 50 that allows the oil O supplied from the oil tank 28 to flow toward the oil cooler 40.

[0055] In an engine of a comparative example as shown in FIG. 4, a first passage 101 from the scavenge pump 30 toward the oil cooler 40 and a second passage 102 from the oil cooler 40 toward the oil tank 28 are internal passages formed inside the crankcase 4.

[0056] By providing the adapter 46 in FIG. 3, it is possible to realize a configuration in which oil O flows in the order of the scavenge pump 30, the oil tank 28, the oil cooler 40, and the feed pump 32 while diverting the existing internal passages 101 and 102. Specifically, the passages 101 and 102 in FIG. 4 correspond to the first and second passages 51 and 52 in FIG. 3, respectively, and the first passage 51 and the second passage 52 communicate with each other via the cooler bypass passage 48. That is, the oil O discharged by the scavenge pump 30 goes toward the oil tank 28 without passing through the oil cooler 40.

[0057] Thus, by providing the adapter 46 in FIG. 3, it is possible to realize a configuration in which oil O flows in the order of the scavenge pump 30, the oil tank 28, the oil cooler 40, and the feed pump 32 only by changing the external passages 53, 54, and 55 while diverting the existing internal passages 51 and 52. Therefore, it can be easily applied to an existing engine.

[0058] However, the configuration of the passage of the oil O is not limited to the above embodiment. For example, when there is no need to divert the existing internal passage, as shown in the second embodiment of FIG. 5, the adapter 46 can be omitted.

[0059] In the example of FIG. 5, the oil O discharged from the oil pan 14 by the scavenge pump 30 is supplied to the oil cooler 40 through the first passage 61. After being cooled by the oil cooler 40, the oil O is supplied to the oil tank 28 through the second passage 62. The oil O stored in the oil tank 28 is supplied to the feed pump 32 through the third passage 63. The oil O pressurized by the feed pump 32 is supplied to the main oil gallery 36 through the fourth passage 64. Also in FIG. 5, the dashed line indicates the internal passage, and the solid line indicates the external passage. In the example of FIG. 5, the third passage 63 is an internal passage, but it may be an external passage.

[0060] The engine system of the present disclosure is suitably mounted on a moving body such as an aircraft or a vehicle. Further, the engine system of the present disclosure is suitably mounted on an off-road vehicle such as a four-wheel buggy (all-terrain vehicle), a utility vehicle, a recreational vehicle, etc.

[0061] The engine system of the present disclosure includes the following aspects 1 to 8. [Aspect 1] A scavenge pump that sucks and discharges oil from the oil pan of the engine, An oil tank that stores the oil discharged by the scavenge pump, An oil cooler that cools the oil derived from the oil tank, A feed pump that supplies the oil derived from the oil cooler to the lubricated parts of the engine, An engine system provided with the above. [Aspect 2] In the engine system according to Aspect 1, further, an engine system provided with a cooling mechanism that supplies cooling air to the oil tank. [Aspect 3] In the engine system according to Aspect 2, the cooling mechanism includes a rotating body attached to the output shaft of the engine. [Aspect 4] In the engine system according to any one of Aspects 1 to 3, the oil cooler is attached to the crankcase of the engine via an adapter, The adapter has a cooler bypass passage that allows the oil supplied from the scavenge pump to flow toward the oil tank, and a cooler inlet passage that allows the oil supplied from the oil tank to flow toward the oil cooler. [Aspect 5] In the engine system according to any one of Aspects 1 to 4, with respect to the orthogonal direction that is orthogonal to both the reciprocating direction of the piston and the axial direction of the crankshaft, the oil cooler is arranged on the intake side in the orthogonal direction of the crankcase of the engine. [Aspect 6] An engine system according to any one of Aspects 1 to 5, wherein the oil tank is disposed outside the engine. [Aspect 7] A moving body equipped with the engine system according to any one of Aspects 1 to 6. [Aspect 8] An off-road vehicle equipped with the engine system according to any one of Aspects 1 to 6.

[0062] 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 system of the above embodiment can also be applied to saddle-riding type vehicles such as motorcycles, tricycles, and four-wheel buggies (all-terrain vehicles). The engine system may be used for an outboard motor or as a propulsion source for an aircraft. In addition, the engine system 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 may be less than six cylinders or seven cylinders or more. The engine system may be provided with a supercharger such as a turbocharger or a supercharger. Therefore, such things are also included in the scope of the present disclosure.

Description of Reference Numerals

[0063] 4 crankcase 14 oil pan 25 output shaft of the engine 28 oil tank 30 scavenge pump 32 feed pump 40 oil cooler 46 adapter 48 cooler bypass passage 50 cooler inlet passage CM cooling mechanism E engine RB rotating body SY engine system

Claims

1. A scavenge pump that sucks and discharges oil from an oil pan of an engine, an oil tank that stores the oil discharged by the scavenge pump, an oil cooler that cools the oil derived from the oil tank, and a feed pump that supplies the oil derived from the oil cooler to lubricated parts of the engine. An engine system comprising these components.

2. The engine system according to claim 1, further comprising a cooling mechanism that supplies cooling air to the oil tank.

3. The engine system according to claim 2, wherein the cooling mechanism includes a rotating body attached to an output shaft of the engine.

4. In the engine system according to claim 1 or 2, the oil cooler is attached to a crankcase of the engine via an adapter, and the adapter has a cooler bypass passage that allows the oil supplied from the scavenge pump to flow toward the oil tank, and a cooler inlet passage that allows the oil supplied from the oil tank to flow toward the oil cooler.

5. In the engine system according to claim 1 or 2, with respect to a direction orthogonal to both the reciprocating direction of the piston and the axial direction of the crankshaft, the oil cooler is arranged on an intake side in the orthogonal direction of the crankcase of the engine.

6. In the engine system according to claim 1 or 2, the oil tank is arranged outside the engine.

7. A scavenge pump that sucks and discharges oil from an oil pan of an engine, an oil tank that stores the oil discharged by the scavenge pump, an oil cooler that cools the oil derived from the oil tank, and a feed pump that supplies the oil derived from the oil cooler to lubricated parts of the engine. A moving body equipped with an engine system having these components.

8. The moving body according to claim 7, which is an off-road vehicle.

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