Engine oil tank

Abstract

This provides an engine oil tank that can maintain both gas venting and oil draining functions. [Solution] An engine oil tank having a gas-liquid separator 9 that divides the inside of the oil tank 4 into an upper chamber 41 and a lower chamber 42, the separator 9 is provided with a communication hole 90 that connects the upper chamber 41 and the lower chamber 42, wherein at least one first communication hole 90a is provided in one region 43 of the separator 9, and at least one second communication hole 90b is provided in the other region 44 of the separator 9, having an opening area (hole diameter) different from that of the first communication hole, and the hole diameter is such that when the lubricating oil 3 stored in the lower chamber 42 is tilted to the maximum extent toward one region 43, the oil level 3al closes the first communication hole 90a, but when it is tilted to the maximum extent toward the other region 44, the oil level 3ar does not close the second communication hole 90b.

Description

Technical Field

[0001] The present invention relates to an oil tank combined with an engine.

Background Art

[0002] As an example of an oil tank combined with an engine, there is a dry sump type engine lubrication system. Hereinafter, the present invention will be described by taking an oil tank combined with a dry sump type engine lubrication system as an example. For example, in Patent Document 1, the lubricating oil in the oil pan is refluxed to the oil tank by the main discharge pump, while the lubricating oil in the cylinder head is refluxed to the oil tank by the sub-discharge pump, and thus the lubricating oil accumulated in the oil tank is supplied to a predetermined lubrication location by the supply pump. Further, gas components such as blow-by gas separated from the lubricating oil inside the oil tank are returned to the intake system of the engine from a discharge portion provided at the upper center of the oil tank.

[0003] At this time, the liquid component and the gas component are separated, and the liquid component (lubricating oil) is supplied to locations in the engine that require lubrication by a pump, and the gas component (blow-by gas) is refluxed to the intake system of the engine. Therefore, inside the oil tank, it is necessary to separate the lubricating oil component supplied to the lubrication locations and the blow-by gas refluxed to the intake system by gas-liquid separation. For this reason, a separator for gas-liquid separation that partitions the inside of the oil tank body is provided.

[0004] For example, Patent Document 2 relates to an oil tank in which lubrication system return fuel and injection system return fuel are supplied back into the oil tank and recirculated, such as in a fuel-recirculating diesel engine that uses fuel as lubricant. The body of the oil tank is divided into upper and lower sections by a separator, with the upper chamber being the first chamber into which fuel returned from inside the engine flows, and the lower chamber being the second chamber where the fuel intake is located. In order to remove impurities that accumulate in the oil tank, a recess for accumulating impurities is provided on one end of the tank, and the separator is formed on a downward sloping surface toward this recess, and a communication hole is provided that penetrates the first and second chambers. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 4284952 [Patent Document 2] Japanese Patent Publication No. 2007-291893 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the oil tank described in Patent Document 1, a separator is not installed, but a gas discharge port is provided in the upper center of the oil tank. Therefore, if a large acceleration occurs in the front-to-back or left-to-right direction, the lubricating oil will not leak out of the discharge port unless the oil level, tilted by the acceleration, reaches the discharge port. However, one of the advantages of a dry-sump lubrication system is that the capacity of the lubricating oil can be increased. If the amount of lubricating oil in the oil tank is increased and the oil level rises, the absence of a separator means that even a small acceleration can cause the oil level to tilt, potentially reaching the discharge port, making it easier for the lubricating oil to leak out.

[0007] On the other hand, in the oil tank described in Patent Document 2, a separator is installed, and the communication holes provided in this separator are used to regulate the pressure in order to create a smooth flow from the upper first chamber to the lower second chamber. Here, lubrication system return fuel and injection system return fuel are dripped into the upper first chamber, and it is also necessary to properly drain the fuel (which is also lubricating oil) accumulated in the first chamber into the second chamber. However, in this respect, although these communication holes can discharge gas from the lower second chamber to the upper first chamber (hereinafter referred to as "gas venting"), they cannot properly drain lubricating oil (hereinafter sometimes referred to as "oil," but they are synonymous) into the lower second chamber (oil chamber) (hereinafter referred to as "oil draining").

[0008] Furthermore, conventional separators have relatively small diameter holes, primarily for pressure regulation. When the oil level reaches these holes, deposits and other substances contained in the recirculating lubricating oil can adhere to them, potentially causing clogging. For the reasons stated above, in the case of an oil tank combined with a dry-sump engine lubrication system, it is desirable to maintain the functions of gas venting and oil drainage, taking into account cases where the oil level tilts significantly due to acceleration.

[0009] Therefore, an oil tank like the one in Figure 4 can be considered. Specifically, this oil tank 4' divides the inside of the tank into an upper chamber 41 and a lower chamber 42 by a separator 9', and the separator 9' has communication holes 90c in each of the regions 43 and 44 in a cross-sectional view. Thus, the separator has at least two communication holes 90c (90cl on the left and 90cr on the right), through which gas can be vented and oil can be drained. In the normal state, as shown in Figure 4(a), the lubricating oil 3 in the upper chamber 41 drips into the lower chamber 42 through the communication holes 90c (indicated by Od), and the oil level 3a' is stored in a horizontal state. On the other hand, the gas in the lower chamber 42 is discharged to the upper chamber 41 through the communication holes 90c (indicated by Gd).

[0010] However, as mentioned above, vehicles can experience large accelerations. Figure 4(b) shows the state of the oil tank when large accelerations are acting on it. This state shows the case when acceleration occurs to the left of the paper (towards one region 43), and the lubricating oil 3 inside the oil tank 4' is pushed to the right (towards the other region 44) by inertial force, causing the oil surface 3a' to tilt significantly. The oil surface 3a' pushed towards the wall passes through the communication hole 90cr of the separator 9' and flows into the upper chamber 41. Furthermore, if centrifugal acceleration is acting or if there is a large amount of lubricating oil 3 in the oil tank, the oil surface 3a' will be pushed forward even more, and the lubricating oil 3 will accumulate in the upper chamber 41 through the communication hole 90cr provided on the other region 44 side. In the end, as shown in Figure 4(b), the communication hole 90cr in the other region 44 becomes blocked with lubricating oil 3, and the function of oil drainage is lost. At this time, although the communication hole 90cl on one side of region 43 is open, it becomes impossible for this communication hole 90cl alone to handle both the gas venting and oil draining functions. If this condition persists for a long time, it will become impossible to achieve both gas venting and oil draining functions simultaneously. In addition, deposits and other substances will accumulate, making clogging more likely.

[0011] This invention has been made in view of the above technical problems, and the object of this invention is to provide an engine oil tank that can maintain both the functions of "gas venting" and "oil draining" even when the oil level of the lubricating oil in the tank is significantly tilted. [Means for solving the problem]

[0012] To achieve the above objective, the present invention provides an engine oil tank having a gas-liquid separator that divides the interior into an upper chamber and a lower chamber, the separator having a communication hole that connects the upper chamber and the lower chamber, characterized in that it has at least two such communication holes, and the opening areas of the two communication holes are different. [Effects of the Invention]

[0013] The oil tank of the present invention is equipped with a gas-liquid separator that divides the interior into an upper chamber and a lower chamber, and this separator is provided with at least two communication holes with different opening areas. That is, the diameter of one communication hole is larger than the diameter of the other communication hole. Therefore, if the oil level of the lubricating oil is significantly tilted, even if the communication hole with the smaller diameter is completely blocked by the oil level, the communication hole with the larger diameter will not be completely blocked. Thus, both gas venting and oil draining functions can be maintained. Furthermore, when multiple communication holes are present, if only small-diameter communication holes are present, many communication holes will be blocked, reducing the gas venting and oil draining functions. However, as in the present invention, if there are large-diameter communication holes, the area of ​​the open portion that is not blocked is kept larger, thus improving gas venting and oil draining performance. In addition, because the hole diameter is larger, blockage due to deposits and the like is less likely to occur, reducing clogging and improving maintainability. As described above, the present invention provides an engine oil tank that can maintain both the functions of "gas venting" and "oil draining" even when the oil level is at its maximum inclination. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram illustrating the configuration of the dry-sump lubrication system targeted in one embodiment of the present invention. [Figure 2] An oil tank according to one embodiment of the present invention, where (a) is a longitudinal cross-sectional view in a state where no acceleration is acting, and (b) is a longitudinal cross-sectional view showing the oil surface when the lubricating oil is tilted to the maximum extent towards one region or the other region, indicated by dashed lines. [Figure 3] Figure 2 shows an oil tank, where (a) is a longitudinal cross-sectional view showing the state in which acceleration is acting and the oil surface is tilted to the maximum extent toward one region (the side with the first communication hole), and (b) is a longitudinal cross-sectional view showing the state in which the oil surface is tilted to the maximum extent toward the other region (the side with the second communication hole). [Figure 4]In a conventional oil tank, (a) is a longitudinal cross-sectional view in a state where no acceleration is acting, and (b) is a longitudinal cross-sectional view showing the state in which acceleration is acting and the oil surface is at its maximum inclination toward the other region. [Modes for carrying out the invention]

[0015] Embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, an oil tank combined with a dry-sump type engine lubrication system will be described as an example. Note that the embodiments described below are merely examples of how the present invention can be carried out and do not limit the present invention.

[0016] Figure 1 is a schematic diagram showing the configuration of a dry-sump lubrication system. To briefly explain the dry-sump lubrication system, in Figure 1, the symbol "1" represents the engine, and an oil pan 2 is provided at its bottom. The dry-sump lubrication system is a system that pumps lubricating oil 3 from the oil pan 2 and resupplies it to parts that require lubrication, such as the engine 1. A scavenging pump 5 is provided to pump the lubricating oil 3 from the oil pan 2 and send it to the oil tank 4. A supply pump 6 that sends the lubricating oil 3 to parts that require lubrication, such as the engine 1, is connected to the oil tank 4. Furthermore, a separator 9 for gas-liquid separation is provided inside the oil tank 4. As the lubricating oil 3 separates into gas and liquid, gas accumulates in the upper chamber of the oil tank 4. A recirculation passage 8 is provided to return this gaseous component, such as blow-by gas, to the intake manifold (or intake system) 7 of the engine 1.

[0017] FIG. 2 is a schematic diagram showing the configuration of the oil tank 4 in an embodiment of the present invention. First, the state shown in FIG. 2(a) shows a state where no acceleration is acting, and the oil tank 4 is vertically mounted on a vehicle (not shown). The oil tank 4 has an overall sealed cylindrical shape, and a separator 9 is installed inside it. The separator 9 divides the inside of the tank into an upper chamber 41 and a lower chamber 42. The separator 9 has a first communication hole 90a formed in one region 43 on the left side and a second communication hole 90b having an opening area (synonymous with the hole diameter, hereinafter sometimes referred to as the hole diameter) different from that of the first communication hole in the other region 44 on the right side. The first communication hole 90a may be a relatively small-diameter hole equivalent to the conventional one. On the other hand, the second communication hole 90b is a relatively large-diameter hole in consideration of the fact that the lubricating oil easily falls. The difference in the opening area (hole diameter) will be described later, but first, it is a requirement that the hole diameter of the first communication hole 90a (hereinafter sometimes simply referred to as the communication hole 90a) is different from the hole diameter of the second communication hole 90b (hereinafter sometimes simply referred to as the communication hole 90b).

[0018] With the above configuration, the lubricating oil 3 pumped out from the oil pan 2 is introduced into the upper chamber 41 of the oil tank 4, and drips (Od) into the lower chamber 42 mainly through a relatively large-diameter communication hole 90b for oil drainage and the like, and is stored as the lubricating oil 3. In a normal state, the oil level 3a of the lubricating oil in the lower chamber 42 is stored in a horizontal state. On the other hand, the gas contained in the lubricating oil 3 in the lower chamber 42 is discharged (Gd) through the communication hole 90c and accumulates in the upper chamber 41. In the above cycle, gas also escapes through the communication hole 90b, and the lubricating oil can also fall through the communication hole 90a to perform the function of oil drainage. Therefore, usually, the communication holes 90a and 90b are used for both gas venting and oil drainage. In this embodiment, an example is described in which a relatively small-diameter communication hole 90a is provided on one region 43 side and a relatively large-diameter communication hole 90b is provided on the other region 44 side, but this may be reversed. That is, a relatively large-diameter communication hole may be provided in one region, and a relatively small-diameter communication hole may be provided in the other region.

[0019] Thus, the form of the communication holes in Fig. 2 is an example, and it can be said that this example has the simplest configuration. In fact, since the oil tank 4 is cylindrical, a plurality of communication holes 90a can be formed as the first communication holes on the side of the above-mentioned one region 43, and similarly, a plurality of communication holes 90b can be formed as the second communication holes on the side of the other region 44. However, the one region and the other region are not necessarily separated by the center line of the longitudinal section. There may be a case where the one region is wide, or there may be a case where the other region is wide. Also, there may be a case where the two regions are mixed. The key is that since the inclination of the lubricating oil level described later changes back and forth and left and right depending on the direction of acceleration, it is preferable that it can correspond to the inclination of the oil level in all directions. From this point of view, a form in which the first communication holes 90a and the second communication holes 90b are mixed in the plane is preferable.

[0020] Next, Fig. 2(b) shows, for example, the oil level when the lubricating oil 3 in the tank is inclined maximally to one region 43 side or the other region 44 side assuming that a large acceleration occurs in the vehicle, indicated by the imaginary lines 3al or 3ar. As shown in the figure, when the lubricating oil 3 is greatly inclined to the one region 43 side, in a sectional view, the oil level 3al covers all of the openings of the communication holes 90a and closes the holes. Therefore, the functions of venting gas and draining oil of the communication holes 90a at this time are lost, and the functions rely solely on the communication holes 90b. On the contrary, when the lubricating oil 3 is greatly inclined to the other region 44 side, in a sectional view, the oil level 3ar covers the openings of the communication holes 90b but does not reach the point of closing all of the openings, leaving some opening portions 90bo. Therefore, the functions of venting gas and draining oil of the communication holes 90b at this time are ensured, and both functions can be maintained together with the communication holes 90a.

[0021] In this embodiment, the first communication hole 90a and the second communication hole 90b are formed as holes with different opening areas. For example, the communication hole 90a can be a hole with a small opening area, similar to that of conventional designs, but the communication hole 90b is preferably a hole with a somewhat larger opening area, considering the function of gas venting and oil drainage. Therefore, the diameter of the second communication hole 90b is set to be larger than the diameter of the first communication hole 90a. Here, the diameters of both holes are set based on the state of the oil level and the communication hole when the oil level of the lubricating oil is at its maximum inclination. That is, as shown in Figure 2(b) above, the diameter of the first communication hole 90a may be such that it is closed by the oil level 3al when it is at its maximum inclination, but the diameter of the second communication hole 90b must be set such that it is not closed by the oil level 3ar when it is at its maximum inclination, leaving at least a part of the opening 90bo. Due to these requirements, even when the oil level is tilted to its maximum extent due to a large acceleration, at least the second communication hole will not be blocked, so the functions of "gas venting" and "oil draining" can be maintained.

[0022] Next, we will explain in more detail, using Figure 3, the case in which acceleration acts on the oil tank according to this embodiment. Figure 3(a) is a longitudinal cross-sectional view showing a state in which acceleration acts to the right of the paper (towards the other region 44) and the oil surface 3a is tilted to the maximum extent toward one region 43 (towards the first communication hole 90a). Figure 3(b) is a longitudinal cross-sectional view showing a state in which acceleration acts to the left of the paper (towards one region 43) and the oil surface 3a is tilted to the maximum extent toward the other region 44 (towards the second communication hole 90b).

[0023] First, as described above, the separator 9 installed in the oil tank 4 has, for example, a relatively small-diameter communication hole 90a on one side of the vertical cross-section 43, and a relatively large-diameter communication hole 90b on the other side of the vertical cross-section 44. As described above, these communication holes 90a and 90b are holes with different opening areas. The policy for setting the different opening areas (hole diameters) here is to consider the case where a large acceleration acts on the vehicle and the lubricating oil tilts. To reiterate, when the lubricating oil 3 in the lower chamber 42 of the oil tank is tilted to the maximum extent towards one side of the vertical cross-section 43, the opening of the communication hole 90a may be closed by the oil level 3a, but when it is tilted to the maximum extent towards the other side of the vertical cross-section 44, the opening of the communication hole 90b is set to a diameter such that the oil level 3a does not completely close it. Therefore, it is necessary to make the communication hole 90b larger in diameter than the communication hole 90a, but it is preferable to set the specific hole diameter for each oil tank based on conditions such as its space capacity, the amount of lubricating oil stored, and the maximum slope of the oil surface.

[0024] Now, Figure 3(a) shows the state when a large acceleration acts to the right of the paper. At this time, due to the inertial force in the opposite direction, the lubricating oil 3 tilts sharply to the left. The oil surface 3a, pushed towards the wall, passes through the communication hole 90a and flows into the upper chamber 41. Subsequently, the lubricating oil 3 blocks the opening of the communication hole 90a, and the function of gas venting and oil drainage through this communication hole 90a is lost. However, the communication hole 90b in the other region remains open and is set to a large diameter, so the function of gas venting and oil drainage is maintained through this communication hole 90b. Even if this state persists for a long time, it is possible to maintain both gas venting and oil drainage functions. Furthermore, if multiple first communication holes 90a and second communication holes 90b are provided, the proportion of communication hole blockage will decrease, so the impact on oil drainage and gas venting will be even less.

[0025] On the other hand, Figure 3(b) shows the state when a large acceleration acts in the leftward direction of the paper. In this case, contrary to the above, the lubricating oil 3 tilts sharply to the right. The oil level 3a, pushed towards the wall, passes through the communication hole 90b and flows into the upper chamber 41. Subsequently, the lubricating oil 3 closes the opening of the communication hole 90b, but a portion of the opening 90bo remains, and it cannot be completely blocked. This is because, as mentioned above, the hole diameter is set to be relatively large so that even when the oil level 3a is tilted to its maximum extent, the opening of the communication hole 90b is not blocked by the oil level 3a. In short, the oil level 3a passes through the communication hole 90b but does not completely block the opening. Therefore, the functions of gas venting and oil drainage are not lost, and the lubricating oil 3 in the upper chamber 41 can immediately drip down. Meanwhile, since the first communication hole 90a remains open at this time, gas venting and oil drainage also occur from here. Thus, in this case as well, the functions of gas venting and oil drainage can be maintained simultaneously. Furthermore, if multiple first communication holes 90a and second communication holes 90b are provided, the impact on oil leakage and gas venting will be even less, as described above.

[0026] To summarize the gist of the embodiments shown in Figures 2 and 3, the present invention provides an oil tank for an engine having a gas-liquid separator 9 that divides the inside of the oil tank 4 into an upper chamber 41 and a lower chamber 42, and the separator 9 is provided with a communication hole that penetrates the upper chamber 41 and the lower chamber 42, and when the oil tank 4 is viewed in a vertical cross-section, for example, at least one first communication hole 90a is provided in one region 43 of the separator 9 with its center as the boundary, and In the other region 44 of the separator 9, at least one second communication hole 90b is provided, which has a different opening area (hole diameter) from the first communication hole 90a. The hole diameter is such that when the lubricating oil 3 in the lower chamber 41 is tilted to the one region 43 side, the oil level 3al closes the first communication hole 90a, but when it is tilted to the other region 44 side, the oil level 3ar does not close the second communication hole 90b.

[0027] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be implemented with appropriate modifications as needed. For example, as mentioned above, the first and second communication holes are not limited to one, but may be provided in multiple numbers, or they may be mixed in one region and the other region. Furthermore, the one region and the other region do not need to be positioned symmetrically with respect to the center line of the vertical cross-section. Furthermore, the first and second communication holes do not need to be round; they may be square, triangular, rhombic, or other shapes. They may also be tapered in cross-section, narrowing towards the bottom, to facilitate oil drainage, or a filter may be attached. Furthermore, a valve mechanism for opening and closing the first and second communication holes may be provided, and a system may be added that controls the opening and closing of the communication holes by operating the valve mechanism as appropriate according to the oil level. Furthermore, although this embodiment uses an oil tank for a dry-sump engine lubrication system as an example, the present invention can also be applied to oil tanks used in combination with other engine systems. [Explanation of Symbols]

[0028] 1: Engine 2: Oil pan 3: Lubricating oil 3a, 3al, 3ar, 3a': Oil level 4, 4': Oil tank 5: Scavenging pump 6: Supply pump 7: Intake System 8: Recirculation channel 9, 9': Separator 90a: First communication hole 90b: Second communication hole 90bo: Some remaining openings 90c: Communication hole 41: Upper chamber 42: Lower chamber 43: One of the domains 44: The other domain Gd: Gas emissions Od: Oil dripping

Claims

[Claim 1] An engine oil tank having a gas-liquid separator that divides the interior into an upper chamber and a lower chamber, and the separator is provided with a communication hole that connects the upper chamber and the lower chamber, An engine oil tank characterized by having at least two of the aforementioned communication holes, wherein the opening areas of the two communication holes are different.

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