Oil tank for internal combustion engines

Abstract

To prevent exposure of an oil outlet from an oil surface in an oil tank.SOLUTION: An oil tank 50 has: a first part 60 having an oil inlet 61 into which an oil flows; and a second part 70 having an oil outlet 92 from which the oil flows out. The second part 70 has: a cylindrical base part 80 having a communication opening 81, which is an opening communicating with the interior of the first part 60; and a bottom wall part 90 which closes one end of the base part 80. The oil outlet 92 is located at the bottom wall part 90. When the longest distance between an outer edge of the communication opening 81 and an outer edge of the oil outlet 92 when the second part 70 is planarly viewed in a direction along a center axis of the base part 80 is referred to as a lateral length LX and the shortest distance between an outer edge of the oil outlet 92 and an outer edge of the communication opening 81 in the direction along the center axis of the base part 80 is referred to as a vertical length LY, a value obtained by dividing the vertical length LY by the lateral length LX is 2 or larger.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an oil tank for an internal combustion engine. [Background technology]

[0002] The lubrication system of the internal combustion engine disclosed in Patent Document 1 employs a so-called dry sump type lubrication method. That is, the lubrication system includes an internal combustion engine, an oil tank, a first passage, and a second passage. The internal combustion engine has a V-shaped cylinder block. The oil tank is located outside the internal combustion engine and inside the V shape of the cylinder block. The oil tank stores oil. The first passage extends from the internal combustion engine to the oil tank. The oil after lubricating the internal combustion engine reaches the oil tank through the first passage. The second passage extends from the oil tank to the internal combustion engine. The oil inside the oil tank reaches the internal combustion engine through the second passage. When this type of lubrication method is adopted, the oil storage volume at the bottom of the internal combustion engine can be reduced, making it possible to miniaturize the internal combustion engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 05-306611 Summary of the Invention [Problem to be solved by the invention]

[0004] In a lubrication system such as that described in Patent Document 1, the oil level inside the oil tank tilts depending on the driving conditions of the vehicle, such as sharp turns and rapid acceleration. When the oil level tilts in this way, the connection point of the second passage with the oil tank may become exposed above the oil level. In this case, problems such as air intake are likely to occur in the second passage. [Means for solving the problem]

[0005] The oil tank for an internal combustion engine for solving the above problems comprises: It is installed in a four-wheeled vehicle for racing that runs on a circuit, and the four-wheeled vehicle has An oil tank provided separately from an internal combustion engine and capable of storing oil therein for lubricating the internal combustion engine, the oil tank having a first section having an inlet through which oil discharged from the internal combustion engine flows in, and a second section having an outlet through which oil to be introduced into the internal combustion engine flows out, the second section having a cylindrical base section having an opening communicating with the inside of the first section, and a bottom wall section closing one end of the base section, the outlet being located in the bottom wall section, a central axis of the base portion is perpendicular to a horizontal plane, and when oil is pooled in the second portion, a minor angle between the horizontal plane and the oil surface when the four-wheeled vehicle is traveling is 70 degrees or less; When the second part is viewed in a plane facing the central axis of the base part, the longest distance between the outer edge of the opening and the outer edge of the outlet is defined as the horizontal length, and the shortest distance between the outer edge of the outlet and the outer edge of the opening in the direction along the central axis of the base part is defined as the vertical length, and the value obtained by dividing the vertical length by the horizontal length is 2 or more.

[0006] The oil tank is mounted on the vehicle in the following installation position. The installation position is a position in which the central axis of the base portion extends along the top and bottom of the vehicle, and the bottom wall portion is located below the vehicle when viewed from the base portion. In this case, in the above configuration, even if the inclination angle of the oil surface with respect to the horizontal plane becomes considerably large depending on the running conditions of the vehicle, the outflow port is submerged in the oil. Specifically, if the inclination angle of the oil surface with respect to the horizontal plane is approximately 63 degrees or less, the outflow port is submerged in the oil. Therefore, even if the vehicle accelerates or turns, the outflow port can be prevented from being exposed above the oil surface. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a lubrication system for an internal combustion engine. [Diagram 2] FIG. 2 is a cross-sectional view of the oil tank. [Diagram 3] FIG. 3 is a plan view of the oil tank as viewed from below. [Figure 4] FIG. 4 is a schematic diagram showing an example of the position of the oil surface in an oil tank of a comparative example. [Diagram 5] FIG. 5 is a schematic diagram showing an example of the position of the oil level in the oil tank. [Figure 6] FIG. 6 is a cross-sectional view showing a modified example of the oil tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of an oil tank for an internal combustion engine applied to a vehicle will be described with reference to the drawings. The vehicle of this embodiment is a four-wheeled automobile for racing that runs on a circuit. The circuit is a circular road for racing. In the following, each configuration related to the oil tank will be described based on the top, bottom, front and rear of the vehicle.

[0009] <General configuration of internal combustion engine> 1, the vehicle 200 has an internal combustion engine 11. The internal combustion engine 11 is a drive source of the vehicle 200. The internal combustion engine 11 has an oil pan 24, a cylinder block 21, a first cylinder head 30A, a second cylinder head 30B, and a crankshaft 12.

[0010] The oil pan 24 is shaped like a rectangular box. The cylinder block 21 is located above the oil pan 24. The cylinder block 21 has a base portion 22, a first bank portion 23A, and a second bank portion 23B.

[0011] The base 22 has a rectangular frame shape. The base 22 is fixed to the upper end of an oil pan 24. The base 22 and the oil pan 24 define a crank chamber. The crank chamber houses the crankshaft 12. A central axis 12C of the crankshaft 12 extends from the front to the rear of the vehicle 200.

[0012] The first bank portion 23A protrudes upward from the base 22. The second bank portion 23B also protrudes upward from the base 22. When viewed in a plan view along the central axis 12C of the crankshaft 12, the first bank portion 23A and the second bank portion 23B extend so as to move away from each other as they move away from the base 22. In other words, when viewed in a plan view along the central axis 12C of the crankshaft 12, the first bank portion 23A and the second bank portion 23B are arranged in a V-shape.

[0013] The first bank portion 23A has a rectangular parallelepiped shape as a whole. The first bank portion 23A has a plurality of cylinders 21T. Each cylinder 21T is a space partitioned by the first bank portion 23A and is a space for burning fuel. The plurality of cylinders 21T are aligned along the central axis 12C of the crankshaft 12.

[0014] Second bank section 23B has a similar configuration to first bank section 23A, so a detailed description of second bank section 23B will be omitted. The first cylinder head 30A has a rectangular parallelepiped shape as a whole. The first cylinder head 30A is fixed to the surface of the tip of the first bank portion 23A in the direction protruding from the base portion 22. The first cylinder head 30A has an intake port 36 for introducing intake air into each cylinder 21T of the first bank portion 23A. The intake port 36 is connected to an intake passage that takes in intake air from the outside. Note that the intake passage is not shown in FIG. 1. The first cylinder head 30A has an exhaust port 37 for discharging exhaust gas from each cylinder 21T of the first bank portion 23A. The exhaust port 37 is connected to an exhaust passage that discharges exhaust gas to the outside. Note that the exhaust passage is not shown in FIG. 1.

[0015] The second cylinder head 30B is fixed to the surface of the tip of the second bank portion 23B in the direction protruding from the base portion 22. The configuration of the second cylinder head 30B is obtained by replacing the configuration for each cylinder 21T of the first bank portion 23A in the first cylinder head 30A with the configuration for each cylinder 21T of the second bank portion 23B. Therefore, a detailed description of the second cylinder head 30B will be omitted.

[0016] The internal combustion engine 11 has an oil passage 27 through which oil flows. The oil passage 27 is connected to various parts of the internal combustion engine 11 that require lubrication. After lubricating the various parts of the internal combustion engine 11, the oil reaches the oil pan 24. In FIG. 1, the oil passage 27 is diagrammatically illustrated by an arrow.

[0017] <Lubrication system for internal combustion engines> The vehicle 200 has a lubrication system 10 for an internal combustion engine 11. In addition to the internal combustion engine 11, the lubrication system 10 has an oil tank 50, a first passage 41, a second passage 42, a scavenging pump 43, and a feed pump 44.

[0018] The oil tank 50 is separate from the internal combustion engine 11. The oil tank 50 is hollow. Oil is stored inside the oil tank 50. The oil tank 50 is fixed to the internal combustion engine 11 by a fixing structure (not shown). The oil tank 50 is located between the first bank portion 23A and the second bank portion 23B of the cylinder block 21, and toward the front of the cylinder block 21 in the direction along the central axis 12C of the crankshaft 12. The oil tank 50 will be described in detail later.

[0019] The first passage 41 extends from the internal combustion engine 11 to the oil tank 50. In FIG. 1, the first passage 41 is diagrammatically indicated by a dashed line. An upstream end 41a of the first passage 41 is connected to an opening provided at the bottom of the oil pan 24. A downstream end 41b of the first passage 41 is connected to the oil tank 50. As a result, the first passage 41 connects the inside of the oil pan 24 to the inside of the oil tank 50. The scavenging pump 43 is located midway through the first passage 41. The scavenging pump 43 pumps oil from the internal combustion engine 11 to the oil tank 50.

[0020] The second passage 42 extends from the oil tank 50 to the internal combustion engine 11. In FIG. 1, the second passage 42 is diagrammatically shown by a dashed line. An upstream end 42a of the second passage 42 is connected to the oil tank 50. A downstream end 42b of the second passage 42 is located inside the internal combustion engine 11 and is connected to the oil passage 27 of the internal combustion engine 11. As a result, the second passage 42 connects the inside of the oil tank 50 to the inside of the internal combustion engine 11. The feed pump 44 is located midway through the second passage 42. The feed pump 44 pumps oil from the oil tank 50 to the internal combustion engine 11.

[0021] <Overall structure of oil tank> 2, the oil tank 50 has a first section 60, a second section 70, and a gas-liquid separator 51. In this embodiment, the first section 60 and the second section 70 are integrally molded.

[0022] The first part 60 is rectangular and hollow. That is, the first part 60 has six walls forming its outer contour. Of these six walls, the walls excluding the lower wall 60a and the upper wall 60b are referred to as side walls. The first part 60 has an inlet 61. The inlet 61 is an opening provided in one of the four side walls of the first part 60. The inlet 61 is connected to the downstream end 41b of the first passage 41. Through the inlet 61, oil discharged from the internal combustion engine 11 flows into the inside of the first part 60.

[0023] The gas-liquid separator 51 is located inside the first section 60. The gas-liquid separator 51 is located in an upper portion of the first section 60. The gas-liquid separator 51 is approximately cylindrical. Oil is supplied into the gas-liquid separator 51 through an inlet 61. The oil supplied into the gas-liquid separator 51 is separated from the gas as it flows down while rotating along the inner circumferential surface of the gas-liquid separator 51.

[0024] The first section 60 has a gas discharge passage 53. The gas discharge passage 53 is cylindrical. One end of the gas discharge passage 53 opens in an upper wall 60b of the first section 60. The gas discharge passage 53 is located directly above the gas-liquid separator 51.

[0025] The second part 70 has a base part 80 and a bottom wall part 90. The base part 80 is cylindrical. The inner diameter of the base part 80 is constant from the upper end to the lower end of the base part 80. The upper end of the base part 80 opens in the lower wall 60a of the first part 60. That is, the area of ​​the opening at the upper end of the base part 80 is smaller than the area of ​​the lower wall 60a of the first part 60. In the following, the opening at the upper end of the base part 80 is referred to as a communication opening 81. The opening surface of the communication opening 81 is perpendicular to the central axis of the base part 80. When the oil tank 50 is mounted on the vehicle 200, the base part 80 is located below the first part 60. The central axis of the base part 80 is parallel to the vertical axis of the vehicle 200. In FIG. 2, the position of the communication opening 81 is indicated by a two-dot chain line for convenience.

[0026] The bottom wall portion 90 is in the form of a circular flat plate. The diameter of the bottom wall portion 90 is approximately the same as the inner diameter of the base portion 80. The bottom wall portion 90 is located at the lower end of the base portion 80. That is, the bottom wall portion 90 closes the opening at the lower end of the base portion 80. The bottom wall portion 90 is perpendicular to the central axis of the base portion 80. That is, the bottom wall portion 90 is in an approximately horizontal position.

[0027] An upper surface of the bottom wall portion 90 and an inner surface of the base portion 80 define an oil storage space. Although not shown in Fig. 2, the oil discharged from the gas-liquid separator 51 is stored in the storage space. The space inside the first portion 60 and outside the gas-liquid separator 51 serves as an auxiliary storage space. The oil that cannot be stored in the storage space of the second portion 70 is stored in this auxiliary storage space.

[0028] The bottom wall portion 90 has an outflow port 92. The outflow port 92 is an opening provided in the bottom wall portion 90. In this embodiment, the outflow port 92 is circular. The upstream end 42a of the second passage 42 is connected to the outflow port 92. Through the outflow port 92, oil to be introduced into the internal combustion engine 11 flows out from the inside of the oil tank 50.

[0029] Hereinafter, a plan view of the second part 70 in a direction along the central axis of the base part 80 will be referred to as a specified plan view. In the specified plan view, the outflow port 92 is located toward the outside of the bottom wall part 90 when viewed from the center of the bottom wall part 90. In this embodiment, the outflow port 92 is located to the side of the vehicle 200 when viewed from the center of the bottom wall part 90. As shown in FIG. 3, a part of the outer edge of the outflow port 92 overlaps with a part of the outer edge of the communication opening 81 in the specified plan view.

[0030] <Details of various dimensions in Part 2> Various dimensions of the second portion 70, such as the inner diameter of the base portion 80 and the length along the central axis of the base portion 80, are determined taking into consideration the relationship between the maximum inclination angle θm and the specific angle θ, which will be described next.

[0031] The maximum inclination angle θm will now be described. When the vehicle 200 runs on a circuit in a competition or the like, the vehicle 200 turns at a considerably high running speed. At that time, the vehicle 200 is subjected to a considerably large acceleration to the left and right. As a result, the oil level in the oil tank 50 is considerably inclined with respect to the horizontal plane. The maximum value of the inclination angle of the oil level with respect to the horizontal plane that can occur at this time is called the maximum inclination angle θm. The maximum inclination angle θm is, for example, 70 degrees. The maximum inclination angle θm can be determined from an experiment or a simulation.

[0032] The specific angle θ will be described. First, the horizontal length LX and vertical length LY, which are the premise of the angle θ, will be described. As shown in FIG. 3, the horizontal length LX is the longest distance between the outer edge of the communication opening 81 and the outer edge of the outlet 92 in a specified plan view. In detail, the horizontal length LX is the distance from a specific portion 81s of the outer edge of the communication opening 81 to a specific portion 92s of the outer edge of the outlet 92. Here, in the specified plan view, a virtual line connecting the center 81v of the communication opening 81 and the center 92v of the outlet 92 is called a specific virtual line D. In the above specified plan view, the specific portion 81s of the outer edge of the communication opening 81 is a portion of the outer edge of the communication opening 81 on the specific virtual line D, and is a portion on the opposite side of the outlet 92 across the center 81v of the communication opening 81. In addition, in the specified plan view, the specific portion 92s of the outer edge of the outlet 92 is a portion of the outer edge of the outlet 92 on the specific virtual straight line D, and is a portion on the opposite side of the center 81v of the communication opening 81 across the center 92v of the outlet 92. In this embodiment, both the communication opening 81 and the outlet 92 are circular, and due to the positional relationship in which the outer edge of the communication opening 81 and part of the outer edge of the outlet 92 overlap, the horizontal length LX substantially coincides with the diameter of the communication opening 81. In other words, the horizontal length LX substantially coincides with the inner diameter of the base portion 80.

[0033] 2, the vertical length LY is the shortest distance between the outer edge of the outlet 92 and the outer edge of the communication opening 81 of the base portion 80 in a direction along the central axis of the base portion 80. In this embodiment, both the bottom wall portion 90 and the opening surface of the communication opening 81 are perpendicular to the central axis of the base portion 80. Therefore, the vertical length LY is the distance from the upper surface of the bottom wall portion 90 to the communication opening 81 in a direction along the central axis of the base portion 80.

[0034] The imaginary line connecting the specific portion 81s of the outer edge of the communication opening 81 and the specific portion 92s of the outer edge of the outlet 92 is referred to as the symmetric imaginary line P. The specific angle θ is the minor angle of the angle formed between the upper surface of the bottom wall portion 90 and the symmetric imaginary line P. This specific angle θ is a function of the vertical length LY and the horizontal length LX, as shown in (Equation 1). (Equation 1) θ = tan(LY / LX) The dimensions of the second portion 70 are determined so that the specific angle θ is greater than the maximum inclination angle θm. In this embodiment, the set value U obtained by dividing the vertical length LY by the horizontal length LX is 3, that is, the specific angle θ is approximately 72 degrees.

[0035] <Operation of the embodiment> Consider an oil tank 150 of a comparative example shown in Fig. 4. This oil tank 150 has a first part 160 and a second part 170 similar to the oil tank 50 of this embodiment. However, the second part 170 has the following configuration. That is, the second part 170 has the same vertical length LY as the second part 70 of the oil tank 50 of this embodiment, and the dimension of the inner diameter of the base part 180 is adjusted so that the set value U is 1. In this case, since the set value U is 1, the specific angle θa formed between the target imaginary straight line Pa and the upper surface of the bottom wall part 190 is 45 degrees.

[0036] Now, assume that as the vehicle 200 turns, acceleration acts on the vehicle 200 in the direction opposite to the outlet 192 across the central axis of the base portion 180. At the same time, assume that the oil level is tilted with respect to the horizontal plane so as to move away from the outlet 192 as it moves upward. Assume that the inclination angle of the oil level at this time becomes the maximum inclination angle θm. As described above, the specific angle θa of the comparative example is 45 degrees. That is, the specific angle θa is smaller than the maximum inclination angle θm. In this case, as shown by the two-dot chain line W1 in FIG. 4, if the amount of oil in the oil tank 50 is not very large, the oil level W1 moves toward the opposite side of the outlet 192 to a position considerably distant from the outlet 192. Then, the outlet 192 is exposed from the oil level W1. In order to prevent the outlet 92 from being exposed from the oil level in the configuration of the comparative example, a considerably large amount of oil needs to be present in the oil tank 150, as shown by the two-dot chain line W2 in FIG. 4. The two-dot chain line W2 indicates the oil level, similar to the two-dot chain line W1.

[0037] In contrast, as shown in FIG. 5, in the configuration of this embodiment in which the set value U is 3, the horizontal length LX is shorter than that of the comparative example, so that even if the amount of oil in the oil tank 50 is not so large, the oil level W inclined to the maximum inclination angle θm remains near the outlet 92. In addition to this, the amount of oil stored in the oil tank 50 is basically secured to a degree that spans both the second part 70 and the first part 60 when the oil level W is inclined. And, as shown in the example of FIG. 5, even when the amount of oil in the oil tank 50 is small, there is enough oil in the oil tank 50 that the oil level W passes through the specific portion 81s of the outer edge of the communication opening 81. And, even if the oil level W passes through the specific portion 81s of the outer edge of the communication opening 81, if the specific angle θ is larger than the maximum inclination angle θm, the outlet 92 is submerged in the oil. Therefore, in the configuration of this embodiment, the outlet 92 is always located in the oil.

[0038] <Effects of the embodiment> In order to reduce the weight of the racing vehicle 200, it is desirable to minimize the amount of oil stored in the oil tank 50. On the other hand, if the amount of oil is reduced without any consideration of the shape and dimensions of the oil tank 50, there is a risk that the outlet 92 will be exposed from the oil surface when the oil surface tilts due to the vehicle 200 turning, as shown in the above comparative example.

[0039] In this regard, in the oil tank 50 of this embodiment, various dimensions of the second portion 70 are set so that the specific angle θ is larger than the maximum inclination angle θm of the oil level. As a result, if a certain amount of oil is secured in the oil tank 50, it is possible to prevent the outlet 92 from being exposed above the oil level even if the oil level is inclined to the maximum inclination angle θm. In other words, the configuration of this embodiment can achieve both a reduction in the amount of oil and prevention of the outlet 92 from being exposed above the oil level.

[0040] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0041] The position of the outlet 92 in the bottom wall portion 90 is not limited to the example of the above embodiment. For example, the outlet 92 may be provided in the front or rear of the vehicle 200 as viewed from the center of the bottom wall portion 90. In these cases, the running conditions of the vehicle 200 in which the outlet 92 may be exposed above the oil surface may differ from those in the above embodiment. That is, the outlet 92 may be exposed above the oil surface when the vehicle 200 accelerates or decelerates. Even in these cases, if the various dimensions of the second portion 70 are set in consideration of the set value U as in the above embodiment, the amount of oil can be reduced and the outlet 92 can be prevented from being exposed above the oil surface.

[0042] The position of the outlet 192 does not have to be an outer portion of the bottom wall portion 90. As shown in FIG. 6, the outlet 92 may be provided at a position closer to the center of the bottom wall portion 90. Even in this case, a specific portion 81s on the outer edge of the communication opening 81 and a specific portion 92s on the outer edge of the outlet 92 may be defined in the same manner as in the above embodiment. Then, the horizontal length LX may be defined as the distance between these specific portions. The vertical length LY may also be defined in the same manner as in the above embodiment. Then, various dimensions of the second portion 70 may be set so that the set value U calculated from the horizontal length LX and the vertical length LY becomes an appropriate value.

[0043] The set value U is not limited to the example of the above embodiment. The set value U may be equal to or greater than 2. For example, if the set value U is 2, the outlet 92 can be prevented from being exposed above the oil surface even when the inclination angle of the oil surface reaches about 60 degrees.

[0044] The overall configuration of the second part 70 is not limited to the example of the embodiment. For example, the base part 80 may be a square tube in which a cross section perpendicular to the central axis of the base part 80 is configured to be a polygon. The base part 80 may be cylindrical. The shape of the bottom wall part 90 may be changed to match the shape of the opening edge of the base part 80. Then, one end of the base part 80 may be closed by the bottom wall part 90. Even if the shapes of the base part 80 and the bottom wall part 90 are changed from the examples of the embodiment, the longest distance between the outer edge of the communication opening 81 and the outer edge of the outlet 92 in the specified plan view may be the horizontal length LX. Also, the shortest distance between the outer edge of the outlet 92 and the outer edge of the communication opening 81 in the direction along the central axis of the base part 80 may be the vertical length LY. Then, various dimensions of the second part 70 may be set so that the set value U calculated from the horizontal length LX and the vertical length LY is 2 or more.

[0045] The inner surface of the base portion 80 may be tapered in a direction along the central axis of the base portion 80. Even in this case, the various dimensions of the second portion 70 can be set by defining the horizontal length LX and the vertical length LY as in the above modified example.

[0046] The shape of the outlet 92 is not limited to the example in the above embodiment. The outlet 92 may be any shape as long as it can discharge the oil inside the oil tank 50 to the outside. For example, the outlet 92 may be rectangular. The horizontal length LX and the vertical length LY may be defined according to the shape of the outlet 92.

[0047] The base portion 80 does not have to be open at the upper end. That is, a separate opening for communication with the first portion 60 may be provided in the wall of the base portion 80. In this case, the opening communicating with the first portion 60 may be regarded as the communication opening 81, and the vertical length LY and the set value U described above may be determined.

[0048] The configuration of the first part 60 is not limited to the example of the embodiment described above. For example, the outer shape of the first part 60 may be spherical. When the configuration of the communication opening 81 of the second part 70 is changed from that of the embodiment described above, as in the above modified example, the shape of the first part 60 may be appropriately designed so that the inside of the second part 70 and the inside of the first part 60 can communicate with each other through the communication opening 81 provided in the base part 80. The first part 60 may have an inlet 61 through which the oil discharged from the internal combustion engine 11 flows.

[0049] It is not essential that the gas-liquid separator 51 is accommodated in the first section 60. Regardless of the presence or absence of the gas-liquid separator 51, the oil tank 50 only needs to be able to store oil. The first portion 60 and the second portion 70 may be molded separately in advance and then joined together later.

[0050] The manner in which the oil tank 50 is mounted on the vehicle 200 is not limited to the example of the above embodiment. That is, when the oil tank 50 is mounted on the vehicle 200, the central axis of the base portion 80 may be inclined with respect to the vertical axis of the vehicle 200. Also, the oil tank 50 may not be fixed to the internal combustion engine 11, but may be fixed to a frame member of the vehicle 200 at a position away from the internal combustion engine 11.

[0051] The configuration of the lubrication system 10 for the internal combustion engine 11, including the internal combustion engine 11 itself, is not limited to the example of the above embodiment. For example, the internal combustion engine 11 may not be a V-type engine, but may have only one row of cylinders. Regardless of the configuration or type of the internal combustion engine 11, if the oil tank 50 is employed, the oil can be stored at a location separate from the internal combustion engine 11. This allows the oil storage volume at the bottom of the internal combustion engine 11 to be reduced.

[0052] The vehicle 200 equipped with the oil tank 50 is not limited to a vehicle for racing on a circuit. Regardless of the type of vehicle 200, if the oil tank 50 is used, the outlet 92 of the oil tank 50 can be prevented from being exposed above the oil surface even if the inclination angle of the oil surface becomes considerably large. [Explanation of symbols]

[0053] LX: Width LY…Vertical length 11...Internal combustion engine 50…Oil tank 60…Part 1 61...Inlet 70…Part 2 80…Base 81…Communication opening 90…Bottom wall 92…Outlet

Claims

[Claim 1] An oil tank that is mounted on a four-wheeled automobile for racing on a circuit and is provided separately from an internal combustion engine of the automobile, and that is capable of storing oil for lubricating the internal combustion engine, A first portion has an inlet through which oil discharged from the internal combustion engine flows, and a second portion has an outlet through which oil to be introduced into the internal combustion engine flows out, The second portion has a cylindrical base portion having an opening communicating with the inside of the first portion, and a bottom wall portion closing one end of the base portion, The outlet is located in the bottom wall portion, The central axis of the base portion is perpendicular to the horizontal plane, When the four-wheeled vehicle is traveling in a state in which oil is pooled in the second portion, a minor angle between a horizontal plane and an oil surface is 70 degrees or less, When the second portion is viewed in a plan view in a direction along the central axis of the base portion, the longest distance between the outer edge of the opening and the outer edge of the outlet is defined as the horizontal length, and the shortest distance between the outer edge of the outlet and the outer edge of the opening in a direction along the central axis of the base portion is defined as the vertical length. The value obtained by dividing the vertical length by the horizontal length is 2 or more. Oil tank for internal combustion engines.

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