Oil Circulation Device

Abstract

To provide an oil circulation device capable of preventing the degradation of the sucking performance of a scavenging pump using oil supplied from an oil pump for pump priming while securing the sucking performance of the scavenging pump at starting an engine.SOLUTION: An oil circulation device 1 includes a switching valve 40 having a first port 401a communicated with a discharge port of an oil pump 31, a second port 401b communicated with a suction port of a scavenging pump 32, and a third port 401c for relieving oil. The switching valve 40 shuts off the communication of the first port 401a with the second port 401b and the third port 401c when an oil pressure to be supplied to the first port 401a is lower than a first predetermined pressure, communicates the first port 401a with the second port 401b when the oil pressure is approximately equal to the first predetermined pressure, and communicates the first port 401a with the third port 401c when the oil pressure is equal to or higher than a second predetermined pressure higher than the first predetermined pressure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an oil circulation device. [Background technology]

[0002] Conventionally, for example, in an engine equipped with a turbocharger, a lubrication system (oil circulation system) has been known in which an oil catch tank (turbo oil pan) is placed below the turbocharger in addition to an oil pan (main oil pan) placed below the crankcase, and after lubricating the bearings of the turbocharger, which are located lower than the oil pan, the oil collected in the oil catch tank is sucked up by a scavenge pump and returned to the oil pan for storage.

[0003] In such an oil circulation device, for example, if an internal gear pump is used as the scavenge pump, which applies an oil film to the sealing portion to increase sealing and suck up oil, if the engine is left unused for a long period of time without being operated and the oil inside the scavenge pump falls into the oil catch tank, causing the scavenge pump to run out of oil (i.e., the inside of the scavenge pump becomes dry), then when the engine is started again, it may not be possible to generate negative pressure and it may not be able to suck up oil.

[0004] Patent Document 1 discloses a technology for an engine lubrication system in which lubricating oil (oil) flows in the following order: turbo oil pan (oil catch tank), oil circulation pump (scavenge pump), main oil pan (oil pan), and feed pump (oil pump). The technology connects the discharge port side of the oil pump and the suction port side of the scavenge pump with a lubricating oil bypass pipe, and supplies oil (priming water) from the oil pump side to the scavenge pump side while the engine is running, ensuring that oil is always present in the pump chamber of the scavenge pump, thereby ensuring sealing of the sealed parts of the scavenge pump and lubrication of each sliding part. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-266235 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, according to the technology of Patent Document 1, the discharge port side of the oil pump and the suction port side of the scavenge pump are connected by a lubricating oil bypass pipe, and oil (priming) is constantly supplied from the oil pump side to the scavenge pump side, ensuring sealing of the sealed parts of the scavenge pump and lubrication of each sliding part. Therefore, even if the inside of the scavenge pump becomes dry after being left unused for a long period of time, it is possible to prevent the scavenge pump from being unable to suck up oil when the engine is started thereafter.

[0007] However, with the technology of Patent Document 1, as the engine speed increases, the oil pump discharge rate increases, increasing the oil flow rate in the lubricating oil bypass pipe and increasing the amount of oil flowing into the scavenge pump (priming amount), which may reduce the suction performance of the scavenge pump and may result in oil overflowing from the oil catch tank.

[0008] The present invention has been made to solve the above problems, and aims to provide an oil circulation device that can ensure the suction performance of the scavenge pump when the engine is started, while preventing a decrease in the suction performance of the scavenge pump due to oil supplied as priming from the oil pump. [Means for solving the problem]

[0009] An oil circulation device according to one aspect of the present invention includes an oil pump that pressurizes and discharges oil stored in an oil pan; a scavenge pump that pumps out oil collected in an oil catch tank and returns it to the oil pan; a switching valve having a first port connected to the discharge port of the oil pump, a second port connected to the suction port of the scavenge pump, and a third port that relieves the oil, and which selectively switches the communication state of the first port depending on the oil pressure supplied to the first port, wherein the switching valve blocks communication between the first port and the second and third ports when the oil pressure is less than a first predetermined pressure, connects the first port to the second port when the oil pressure is approximately equal to the first predetermined pressure, and connects the first port to the third port when the oil pressure is equal to or greater than a second predetermined pressure that is higher than the first predetermined pressure. [Effects of the Invention]

[0010] According to the present invention, it is possible to ensure the suction performance of the scavenge pump when starting the engine, while preventing a decrease in the suction performance of the scavenge pump due to oil supplied as priming water from the oil pump. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram schematically illustrating a lubrication system (oil flow) of an engine to which an oil circulation device according to an embodiment is applied. [Figure 2] 1 is a diagram showing a configuration of a main part of an oil circulation device according to an embodiment; [Figure 3] 5 is a diagram showing a state of a switching valve when shut off in the oil circulation device according to the embodiment; FIG. [Figure 4] 5 is a diagram showing the state of the switching valve when priming water is supplied (when the second port is open) in the oil circulation device according to the embodiment. FIG. [Figure 5] 5 is a diagram showing the state of the switching valve during oil relief (when the third port is open) in the oil circulation device according to the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same elements are designated by the same reference numerals and redundant explanations will be omitted.

[0013] First, the configuration of an oil circulation device 1 according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a diagram schematically showing a lubrication system (oil flow) of an engine 10 to which the oil circulation device 1 is applied. Figure 2 is a diagram showing the configuration of a main part of the oil circulation device 1.

[0014] The oil circulation device 1 is applied to, for example, an engine 10 equipped with a turbocharger 11. The turbocharger 11 is disposed at a position lower than the engine 10 main body (the oil level in an oil pan 21, which will be described later). The engine 10 may be of any type, for example, a horizontally opposed four-cylinder gasoline engine. The turbocharger 11 is a supercharger disposed between an intake passage and an exhaust passage, and supercharges intake air to achieve high power output and low fuel consumption. The turbocharger 11 has a turbine disposed in the exhaust passage, and a compressor disposed in the intake passage and connected to the turbine by a rotating shaft; the turbine is driven by exhaust energy, thereby compressing air using the coaxial compressor.

[0015] The oil circulation device 1 supplies oil (lubricating oil) to lubricated parts such as the valve mechanism and crankshaft of the engine 10, and to bearings of the turbocharger 11. To this end, the oil circulation device 1 is equipped with an oil pan 21 that stores oil, an oil pump 31 that sucks up the oil stored in the oil pan 21 through a strainer, increases the pressure, and discharges the oil, an oil catch tank 22 that is provided at a lower position than the oil pan 21, and a scavenge pump 32 that pumps out the oil collected in the oil catch tank 22 and returns it to the oil pan 21.

[0016] As the oil pump 31, for example, a trochoid pump (internal gear pump) or the like is used. The oil pump 31 is driven by, for example, the engine 10. Similarly, as the scavenge pump 32, for example, a trochoid pump (internal gear pump) or the like is used. The scavenge pump 32 is also driven by the engine 10.

[0017] For example, oil in an oil pan 21 provided below the engine 10 (crankcase) is sucked up by an oil pump 31 and supplied to lubricated parts such as a valve mechanism of the engine 10. Then, the oil used to lubricate the lubricated parts of the engine 10 drips into the oil pan 21, where it is collected and temporarily stored.

[0018] Meanwhile, part of the oil used to lubricate the lubricated parts of engine 10 (or part of the oil discharged from oil pump 31) is supplied to bearings and the like (lubrication parts) of turbocharger 11, which is located at a position lower than the main body of engine 10. The oil used to lubricate (and cool) turbocharger 11 drips and is collected in oil catch tank 22 disposed below turbocharger 11. The oil is then sucked up by scavenge pump 32 and sent to oil pan 21 through oil passage 54.

[0019] In particular, the oil circulation device 1 has a function of ensuring the suction performance of the scavenge pump 32 when the engine is started, while preventing a decrease in the suction performance of the scavenge pump 32 due to oil supplied as priming water from the oil pump 31. For this reason, the oil circulation device 1 is provided with a switching valve 40.

[0020] The switching valve 40 has a first port 401a that is communicated with the discharge port of the oil pump 31 and is connected to a first oil passage 51 that supplies oil discharged from the oil pump 31, a second port 401b that is communicated with the suction side (expansion side) of the scavenge pump 32 and is connected to a second oil passage 52 that supplies oil as priming to the scavenge pump 32, and a third port 401c that is connected to a third oil passage 53 that relieves oil. The switching valve 40 selectively switches the communication state of the first port 401a (first oil passage 51) depending on the oil pressure (pressure of the oil discharged from the oil pump 31) supplied to the first port 401a.

[0021] More specifically, when the hydraulic pressure is lower than a first predetermined pressure, the switching valve 40 blocks (closes) communication between the first port 401a (first oil passage 51) and the second port 401b (second oil passage 52) and the third port 401c (third oil passage 53). On the other hand, when the hydraulic pressure is substantially equal to the first predetermined pressure, the switching valve 40 connects the first port 401a (first oil passage 51) and the second port 401b (second oil passage 52). Then, the switching valve 40 supplies oil as priming water to the scavenge pump 32. Furthermore, when the hydraulic pressure is equal to or higher than a second predetermined pressure that is higher than the first predetermined pressure, the switching valve 40 connects the first port 401a (first oil passage 51) and the third port 401c (third oil passage 53). Then, the supply of priming water to the scavenge pump 32 is stopped, and the oil is relieved. That is, the switching valve 40 also functions as a relief valve (can also be used as a relief valve).

[0022] The switching valve 40 has a valve case 401 formed, for example, in the shape of a cylinder with a bottom. A first port 401a, a second port 401b, and a third port 401c are formed in the valve case 401 along the axial direction. For example, the first port 401a is formed in a circular shape on one end face (top face) of the valve case 401 (it may be formed on a side face). The second port 401b is formed in a circular shape on a side face of the valve case 401. The third port 401c is formed in a circular shape on the side face of the valve case 401, at a position farther away from the first port 401a than the second port 401b.

[0023] A spool valve 402 formed, for example, in a cylindrical shape is housed inside the valve case 401 so as to be slidable in the axial direction. A through hole 402a, more specifically, a through hole 402a having an L-shaped cross section, where one end of the hole formed in the axial direction intersects with the other end of a hole formed in the radial direction, is formed inside the spool valve 402. One end of the hole formed in the axial direction is connected to the first port 401a (first oil passage 51), and the other end of the hole formed in the radial direction is configured to be able to switch the communication destination (shutoff, second port 401b (second oil passage 52), third port 401c (third oil passage 53)).

[0024] One end face (inner surface) of the valve case 401 and one end face of the spool valve 402 define a hydraulic chamber 403 to which oil discharged from the oil pump 31 is supplied via the first port 401a.

[0025] A biasing member 404 is disposed between the other end face (inner surface) of the valve case 401 and the other end face of the spool valve 402. The biasing member 404 applies a biasing force to the spool valve 402 in a direction to block communication between the first port 401a and the second and third ports 401b and 401c. For example, a coil spring or the like is used as the biasing member 404. The biasing force of the biasing member (coil spring) 404 increases as it is compressed. In other words, the biasing force at the position (first position) where communication between the first port 401a is blocked < the biasing force at the position (second position) where the first port 401a and the second port 401b are connected < the biasing force at the position (third position) where the first port 401a and the third port 401c are connected.

[0026] Spool valve 402 slides in the axial direction according to the force relationship (balance) between the pushing force of the hydraulic pressure in hydraulic chamber 403 and the biasing force of biasing member (coil spring) 404. More specifically, when the product of the hydraulic pressure and the pressure-receiving area of ​​spool valve 402 (multiplied value = pushing force) is less than the biasing force of biasing member 404 when spool valve 402 is located at a position (second position) where first port 401a and second port 401b are connected to each other, spool valve 402 blocks communication between first port 401a (first oil passage 51) and second port 401b (second oil passage 52) and third port 401c (third oil passage 53).

[0027] On the other hand, when the product of the oil pressure and the pressure-receiving area of ​​the spool valve 402 (multiplied value = pressing force) is approximately equal to the biasing force of the biasing member 404 when the spool valve 402 is positioned at the second position where the first port 401a and the second port 401b are connected (second position), the spool valve 402 slides in the axial direction to connect the first port 401a (hydraulic chamber 403) and the second port 401b. Thus, oil is supplied to the scavenge pump 32 as priming water.

[0028] Furthermore, when the product of the oil pressure and the pressure-receiving area of ​​the spool valve 402 (multiplied value = pressing force) is equal to or greater than the biasing force of the biasing member 404 when the spool valve 402 is located at the position (third position) where the first port 401a and the third port 401c are connected, the spool valve 402 slides further in the axial direction to connect the first port 401a (hydraulic chamber 403) and the third port 401c. This stops the supply of priming water to the scavenge pump 32 and relieves the oil.

[0029] Therefore, when the oil pressure becomes higher than the second predetermined pressure, the switching valve 40 transitions the communication state of the first port 401a (first oil passage 51) from a blocked state to a communication state with the second port 401b (second oil passage 52) and then to a communication state with the third port 401c (third oil passage 53). That is, the switching valve 40 supplies oil as priming to the scavenge pump 32 in the transient state (during the transition).

[0030] As described above, the switching valve 40 also functions as a relief valve that relieves oil when the hydraulic pressure reaches or exceeds the second predetermined pressure. Therefore, the switching valve 40 can be used in combination with (or can be diverted from) a conventional relief valve.

[0031] Here, the diameter of through-hole 402a, the opening area of ​​second port 401b, and the biasing force of biasing member (coil spring) 404 are set according to the amount of oil required as priming water by scavenge pump 32 (i.e., so that the required amount can be supplied). For example, when the oil temperature is about 40°C (warm-up mode) and the engine speed at start-up is about 2000 rpm, the oil pressure rises to 6 to 7 K, so biasing member (coil spring) 404 of switching valve (relief valve) 40 is set to open at about 5 K (i.e., so that it opens reliably), for example.

[0032] Next, the operation of the oil circulation device 1 will be described with reference to Figures 3 to 5. Figure 3 is a diagram showing the state of the switching valve (relief valve) 40 in the oil circulation device 1 when it is shut off. Figure 4 is a diagram showing the state of the switching valve (relief valve) 40 in the oil circulation device 1 when priming water is supplied (when the second port 401b is connected). Figure 5 is a diagram showing the state of the switching valve (relief valve) 40 in the oil circulation device 1 when oil is relieved (when the third port 401c is connected).

[0033] When the hydraulic pressure in the hydraulic chamber 403 is lower than the first predetermined pressure, the product of the hydraulic pressure and the pressure-receiving area of ​​the spool valve 402 (multiplied value = pressing force) becomes smaller than the biasing force of the biasing member 404 when the spool valve 402 is located at the position (second position) where the first port 401a and the second port 401b are connected to each other, and therefore, the communication between the first port 401a (first oil passage 51) and the second port 401b (second oil passage 52) and the third port 401c (third oil passage 53) is blocked (the valves are closed), as shown in Fig. 3. Therefore, the supply of oil to the scavenge pump 32 as priming water is stopped.

[0034] When the oil pressure becomes higher than the state shown in FIG. 3 and becomes substantially equal to the first predetermined pressure, the product of the oil pressure and the pressure-receiving area of ​​the spool valve 402 (multiplied value = pressing force) becomes substantially equal to the biasing force of the biasing member 404 when the spool valve 402 is located at the position (second position) where the first port 401a and the second port 401b are connected to each other. As a result, the spool valve 402 slides as shown in FIG. 4, and the first port 401a (first oil passage 51, oil pressure chamber 403) and the second port 401b (second oil passage 52) are connected to each other. As a result, oil is supplied to the scavenge pump 32 as priming water. Here, since the temperature of the oil is low and the viscosity is high when the engine is started after being left unused for a long period of time, the discharge pressure of the oil pump 31 becomes high (the oil pressure becomes high, equal to or higher than the first predetermined value), and oil is supplied to the scavenge pump 32 as priming water.

[0035] 4 and reaches or exceeds a second predetermined pressure that is higher than the first predetermined pressure, the product of the oil pressure and the pressure-receiving area of ​​spool valve 402 (multiplied value = pressing force) becomes equal to or greater than the biasing force of biasing member 404 when spool valve 402 is located at the position (third position) where first port 401a and third port 401c are connected, and spool valve 402 slides as shown in Fig. 5, connecting first port 401a (first oil passage 51, oil chamber 403) and third port 401c (third oil passage 53). Therefore, the supply of oil as priming water to scavenge pump 32 is stopped, and oil is relieved.

[0036] As described above in detail, according to this embodiment, when the hydraulic pressure in the hydraulic chamber 403 becomes approximately equal to the first predetermined pressure, the product (multiplied value = pressing force) of the hydraulic pressure and the pressure-receiving area of ​​the spool valve 402 becomes approximately equal to the biasing force of the biasing member 404 when the spool valve 402 is located at the position (second position) where the first port 401a and the second port 401b are connected to each other. As a result, the first port 401a (first oil passage 51) and the second port 401b (second oil passage 52) are connected to each other. Therefore, oil is supplied to the scavenge pump 32 as priming water. Here, since the temperature of the oil is low and the viscosity is high when the engine is started after being left unused for a long period of time, the discharge pressure of the oil pump 31 becomes high (the hydraulic pressure becomes high, equal to or higher than the first predetermined value), and oil is supplied to the scavenge pump 32 as priming water. Therefore, the suction performance of the scavenge pump 32 can be ensured immediately after the engine is started.

[0037] Furthermore, according to this embodiment, when the oil pressure reaches or exceeds a second predetermined pressure that is higher than the first predetermined pressure, the product of the oil pressure and the pressure-receiving area of ​​the spool valve 402 (multiplied value = pressing force) becomes equal to or greater than the biasing force of the biasing member 404 when the spool valve 402 is located at the position (third position) where the first port 401a and the third port 401c are connected, and the first port 401a (first oil passage 51, oil chamber 403) and the third port 401c (third oil passage 53) are connected. Therefore, the supply of oil as priming water to the scavenge pump 32 is stopped, and the oil can be relieved.

[0038] Furthermore, according to this embodiment, when the oil pressure is less than the first predetermined pressure, the product (multiplied value = pressing force) of the oil pressure and the pressure-receiving area of ​​the spool valve 402 becomes smaller than the biasing force of the biasing member 404 when the spool valve 402 is located at the position (second position) where the first port 401a and the second port 401b are connected to each other, and therefore communication between the first port 401a (first oil passage 51) and the second port 401b (second oil passage 52) and the third port 401c (third oil passage 53) is blocked (the valve is closed). Therefore, when the oil temperature rises after warm-up is completed and the oil viscosity decreases, the supply of oil as priming water to the scavenge pump 32 is stopped, and a decrease in the suction amount (discharge amount) of the scavenge pump 32 can be prevented.

[0039] As a result, according to this embodiment, oil is supplied as priming water when the inside of the scavenge pump 32 is dry (it is not supplied all the time), so it is possible to ensure the suction performance of the scavenge pump 32 when the engine is started while preventing a decrease in the suction performance of the scavenge pump 32 due to the oil supplied as priming water from the oil pump 31.

[0040] Furthermore, according to this embodiment, priming water is supplied to the scavenge pump 32 only immediately after the engine is started after being left unused (when cold), which makes it possible to reduce friction (improve fuel efficiency) and downsize (reduce costs and reduce weight) the oil pump 31 that supplies priming water (compared to a system in which priming water is supplied constantly).

[0041] According to this embodiment, when the hydraulic pressure becomes higher than the second predetermined pressure, the communication state of the first port 401a (first oil passage 51) transitions from a blocked state to a communication state with the second port 401b (second oil passage 52) and then to a communication state with the third port 401c (third oil passage 53). Therefore, in the transient state (during the transition), oil can be supplied as priming water to the scavenge pump 32. Then, when the hydraulic pressure becomes higher, the supply of priming water can be stopped to relieve the oil.

[0042] According to this embodiment, the diameter of through-hole 402a, the opening area of ​​second port 401b, and the biasing force of biasing member 404 are set according to the amount of oil as priming water required by scavenge pump 32. Therefore, the flow rate of oil supplied as priming water and the supply time of priming water (valve open time) can be appropriately set, and the amount of priming water to be supplied can be appropriately set.

[0043] According to this embodiment, the switching valve 40 can also be used as a relief valve (reuse of the relief valve) that relieves oil when the oil pressure reaches or exceeds a second predetermined pressure, which is superior (advantageous) in terms of cost, weight, layout freedom, etc. compared to using a dedicated switching valve.

[0044] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible. For example, the configuration (structure) of the switching valve (relief valve) 40 is not limited to the above embodiment and other configurations (structures) may be used.

[0045] In the above embodiment, a trochoid pump is used as the oil pump 31 and the scavenge pump 32. However, instead of the trochoid pump, for example, an internal gear pump having other tooth shapes may be used. [Explanation of symbols]

[0046] 1 Oil circulation device 10 Engine 11 Turbocharger 21 Oil pan 22 Oil catch tank 31 Oil pump 32 Scavenge Pump 40 Switching valve (relief valve) 401 Valve case 401a Port 1 401b 2nd port 401c 3rd Port 402 Spool valve 402a Through hole 403 Hydraulic Room 404 biasing member (coil spring) 51 No. 1 oil road 52 2nd oilway 53 3rd oil road

Claims

1. an oil pump that pressurizes and discharges oil stored in an oil pan; a scavenge pump that pumps out oil collected in the oil catch tank and returns it to the oil pan; a switching valve having a first port communicated with a discharge port of the oil pump, a second port communicated with a suction port of the scavenge pump, and a third port for relieving oil, the switching valve selectively switching a communication state of the first port in accordance with the hydraulic pressure supplied to the first port; Equipped with The switching valve is When the hydraulic pressure is less than a first predetermined pressure, communication between the first port and the second and third ports is blocked; When the hydraulic pressure is substantially equal to the first predetermined pressure, the first port and the second port are communicated with each other; When the hydraulic pressure is equal to or higher than a second predetermined pressure that is higher than the first predetermined pressure, the first port and the third port are communicated with each other. An oil circulation device characterized by:

2. 2. The oil circulation device according to claim 1, wherein the switching valve transitions the communication state of the first port from a blocked state to a communication state with the second port, via a communication state with the third port, when the oil pressure becomes higher than the second predetermined pressure.

3. The switching valve is a cylindrical valve case in which the first port, the second port, and the third port are formed along the axial direction; a spool valve housed in the valve case so as to be slidable in the axial direction; a hydraulic chamber defined by one end surface of the valve case and one end surface of the spool valve, the hydraulic chamber receiving oil discharged from the oil pump via the first port; a biasing member disposed between the other end surface of the valve case and the other end surface of the spool valve, the biasing member applying a biasing force to the spool valve in a direction to block communication between the first port and the second and third ports; and The spool valve is when the product of the hydraulic pressure and the pressure-receiving area of ​​the spool valve is less than the biasing force of the biasing member when the spool valve is positioned at a position where the first port and the second port are communicated with each other, the communication between the first port and the second port and the third port is blocked; when the product of the hydraulic pressure and the pressure-receiving area of ​​the spool valve is approximately equal to the biasing force of the biasing member when the spool valve is positioned at a position where the first port and the second port are connected to each other, When the product of the hydraulic pressure and the pressure-receiving area of ​​the spool valve is equal to or greater than the biasing force of the biasing member when the spool valve is positioned at a position where the first port and the third port are connected to each other, the first port and the third port are connected to each other.

3. The oil circulation device according to claim 1 or 2.

4. 4. The oil circulation device according to claim 3, wherein the opening area of ​​the second port and the biasing force of the biasing member are set according to the amount of oil required as priming water in the scavenge pump.

5. 5. The oil circulation device according to claim 1, wherein the switching valve is a relief valve that relieves oil when the oil pressure reaches or exceeds the second predetermined pressure.

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