JPH0913934A - Lubricating device for internal combustion engine - Google Patents

Abstract

PURPOSE: To surely increase the oil temperature in a short time by preventing the heat of oil from being discharged to the outside air or being deprived of by a cylinder block when an internal combustion engine is kept at a low temperature. CONSTITUTION: A main oil pan 14 is fitted to the lower face of a cylinder block 12, and an auxiliary oil pan 16 having a capacity smaller than that of the main oil pan 14 is arranged in a crankcase 15. A main oil feed passage 22 covered with a heat insulating layer 33 made of air is provided in the cylinder block 12, and the oil 17 from an oil pump 42 is fed to various lubrication sections via the main oil feed passage 22. The return oil 44 from the lubrication sections is guided to the auxiliary oil pan 16. The oil 17 in the main oil pan 14 is guided to the oil pump 42, and a main oil guide passage 36 having an oil cooler 43 and an auxiliary oil guide passage 38 guiding the oil 17 in the auxiliary oil pan 16 to the oil pump 42 are provided in the middle respectively. Both passages 36, 38 are connected to the oil pump 42 via a thermostat 41 switching both passages 36, 38 in response to the temperature of the oil 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating device for supplying oil to a lubricating portion of a moving part such as a piston or a crankshaft by circulating the oil in the internal combustion engine, and more particularly to a lubricating device for supplying oil to the lubricating portion of a moving part such as a piston or a crankshaft. The present invention relates to a lubricating device for an internal combustion engine that quickly raises the temperature.

[0002]

2. Description of the Related Art Many moving parts such as crankshafts, camshafts, pistons, etc. are incorporated in an internal combustion engine mounted on a vehicle or the like, and the lubricating parts (supporting parts, sliding parts, etc.) of each moving part are incorporated. A lubrication device is provided for supplying oil. In this lubrication system, oil flows through the cylinder block, part of which is the crankshaft,
Supplied to pistons, etc. Also, other oil is supplied to the cam shaft of the cylinder head after passing through the cylinder block. The oil supplied as described above is returned to the oil pan after being used for smooth operation, cooling, maintaining airtightness and the like of each moving part.

By the way, the viscosity of oil changes depending on the oil temperature. In particular, when the temperature of the internal combustion engine itself is low and the oil temperature is low, the viscosity of the oil is highest. Therefore, when the oil temperature is low, the frictional resistance of the oil to the movement of each moving part is large and the friction loss is large. For this, it is desirable to raise the oil temperature early. However, such a measure is practically difficult because a large amount of heat is required at one time in order to rapidly raise the temperature of all the oil in the lubricating device.

Therefore, for example, Japanese Patent Laid-Open No. 55-57611.
In the publication, the oil pan is partitioned into a small-capacity first chamber and a large-capacity second chamber, and each lubricating section and the first chamber are connected by an oil return passage. Both the first and second chambers are connected by a communication passage, and the communication passage and each lubricating portion are connected by an oil supply passage.
A switching valve that operates according to the oil temperature is arranged at the connection portion of the oil supply passage to the communication passage. The switching valve connects the supply passage to the first chamber only when the oil temperature is equal to or lower than a predetermined value, and connects the supply passage to the second chamber when the oil temperature exceeds the predetermined value. This technique attempts to raise the oil temperature early by supplying a small amount of oil in the first chamber to each lubrication unit via the supply passage when the internal combustion engine is at a low temperature.

[0005]

However, in the above-mentioned prior art, a part of the bottom plate of the oil pan also serves as the bottom plate of the first chamber. Therefore, the heat of the oil in the first chamber is
It is easy to be released to the air (outside air) outside the oil pan through the bottom plate. On the contrary, when the wind (traveling wind) generated as the vehicle travels hits the oil pan, the traveling wind easily cools the oil in the room. Further, since the cylinder block itself is cold when the internal combustion engine has a low temperature, when the oil passes through the oil supply passage in the cylinder block, the heat of the oil is taken by the cylinder block. When the heat of the oil is released to the outside air or taken by the cylinder block, the oil temperature does not rise as fast as intended.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to prevent the heat of oil from being released to the outside air or taken by a cylinder block when the internal combustion engine is at a low temperature. An object of the present invention is to provide a lubricating device for an internal combustion engine that can reliably raise the temperature in a short time.

[0007]

In order to achieve the above object, a lubricating device of the present invention comprises a main oil pan mounted on the lower surface of a cylinder block of an internal combustion engine, and a capacity smaller than that of the main oil pan. An auxiliary oil pan disposed in the crank chamber of the engine, a main oil supply passage provided in the cylinder block and covered by a heat insulating means, and oil to each lubrication portion of the internal combustion engine via the main oil supply passage. An oil pump for supplying the oil, a return passage for guiding the return oil from the lubrication section of the internal combustion engine into the sub oil pan, and a main oil introducing passage for guiding the oil in the main oil pan to the oil pump. An oil cooling means provided in the middle of the main oil introducing passage for cooling the oil, and for guiding the oil in the sub oil pan to the oil pump And a secondary oil guide passage, wherein the main oil introduction passage and the auxiliary oil introduction passage is connected to the oil pump via the temperature switching means for switching both said passage in response to the temperature of the oil.

[0008]

When the internal combustion engine is cold, the oil temperature is also low. At this time, for example, when the sub oil introducing passage is opened and the main oil introducing passage is closed by the temperature switching means, a small amount of oil in the sub oil pan is operated by the oil pump to supply the sub oil introducing passage and the main oil. After being supplied to each part of the lubricating portion of the internal combustion engine through the passage, it is guided to the sub oil pan through the return passage. Thus, the oil circulation at low temperature is performed in the sub oil pan → the sub oil introduction passage → the oil pump → the main oil supply passage → each lubrication section → the return passage → the sub oil pan. Here, if the amount of heat transferred to the oil due to the operation of the internal combustion engine is constant, the amount of heat transferred to the oil per unit amount will be greater than when a large amount of oil in the main oil pan is circulated. .

Since the sub oil pan is shielded from the outside air, it does not come into direct contact with the outside air. Instead of the outside air,
The high temperature blow-by gas generated by the operation of the internal combustion engine contacts the outer surface of the sub oil pan. The heat of the blow-by gas passes through the sub oil pan and is transferred to the oil stored therein. Further, since the main oil supply passage is covered by the heat insulating means, heat exchange between the main oil supply passage and the cylinder block is difficult to occur, and the heat of the oil is not easily absorbed by the low temperature cylinder block. Therefore, the oil in the sub oil pan is not only efficiently heated, but also the heat of the oil is not easily released, and the oil temperature rises early.

When the internal combustion engine is hot, the temperature of oil is high. At this time, when the main oil introducing passage is opened by, for example, the temperature switching means, a large amount of oil in the main oil pan is operated by the oil pump to pass through the main oil introducing passage and the main oil supply passage to each part of the lubricating portion of the internal combustion engine. Is supplied to the sub oil pan through the return passage.
When an oil amount exceeding the capacity of the sub oil pan flows in, this oil overflows from the sub oil pan and flows into the main oil pan. In this way, oil circulation at high temperature is performed in the main oil pan → main oil introduction passage → oil pump → main oil supply passage → lubricating parts → return passage → sub oil pan → main oil pan. At this time, since the main oil supply passage is covered by the heat insulating means and the heat of the oil flowing through the supply passage is not easily released, the oil temperature rises. But,
Since the oil is cooled by the oil cooling means when passing through the main oil introduction passage, the oil temperature is prevented from rising excessively.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a vehicle is equipped with a gasoline engine (hereinafter, simply referred to as an engine) 11 as an internal combustion engine. The engine 11 includes a cylinder block 12 and a cylinder head 13 arranged on the cylinder block 12.
And

The cylinder block 12 is made of metal such as cast iron and aluminum. A plurality of cylinder bores are formed in the cylinder block 12, and a piston is reciprocally housed therein. Cylinder block 1
A crankshaft is rotatably supported by a journal on the shaft 2, and the shaft and the piston are connected by a connecting rod. Then, the reciprocating motion of the piston is converted into a rotary motion by the connecting rod and the crankshaft. On the other hand, on the cylinder head 13, a cam shaft having a cam on the outer periphery is rotatably supported by a journal. The camshaft is
It is drivingly connected to the crankshaft by a timing belt (or a timing chain). In this way, the cylinder block 12 and the cylinder head 13 are
Many moving parts, such as a piston, a crankshaft, and a camshaft, are incorporated in the.

A skirt portion is formed in the lower portion of the cylinder block 12, and a main oil pan 14 having an open upper surface is attached to the lower surface of the skirt portion. Main oil pan 1
4 is intended to store the oil 17 and has a large capacity. The space surrounded by the skirt and the main oil pan 14 is the crank chamber 1
It is 5.

An upper side of the crank chamber 15 is provided with a sub oil pan 16 having an open upper surface and having a smaller capacity than the main oil pan 14. In the sub oil pan 16, the oil (return oil 44) after lubricating the lubricating parts (supporting parts, sliding parts, etc.) of the above-mentioned respective motion parts is the plate 4
5 is stored via the cylinder block 12 or the main oil pan 1 by a fixing means such as a stay 18.
4 is fixed. The oil 17 overflowing from the sub oil pan 16 is stored in the main oil pan 14. Here, in order to raise the temperature of the oil 17 rapidly, it is desirable to circulate as little oil 17 as possible. From this point of view, the auxiliary oil pan 16 has a minimum size capable of storing the amount of oil 17 required for lubricating all the moving parts described above.

The sub oil pan 16 is located above the oil surface 19 of the oil 17 in the main oil pan 14, and the high temperature blow-by gas 21 is applied to the outer surface 1 of the sub oil pan 16.
6a is touched. Blow-by gas 21
Among the combustion gases generated by the combustion of the air-fuel mixture of fuel and air, is the gas leaking into the crank chamber 15 from the gap between the piston and the cylinder bore.

A main oil supply passage (oil main hole) 22 is provided in the cylinder block 12. More specifically, as shown in FIG. 3, the cylinder block 12
A hole 23 is formed in the inside, and a plurality of oil passages 25 extend from a wall surface 24 of the hole 23 toward a lubrication portion of each moving component such as a piston and a crankshaft. A passage forming member 26 is arranged in the hole 23. Passage forming member 26
Is composed of a circular tubular pipe body 27 having a diameter smaller than that of the hole 23 and a plurality of circular tubular connecting portions 28 extending outward from the pipe body 27 in the radial direction. The internal space of the portion 28 constitutes the main oil supply passage 22. A flange 28a is formed at the outer end of each connecting portion 28, and the passage forming member 26 is in contact with the wall surface 24 of the hole 23 at the flange 28a. Therefore, in this state, the pipe body 27 is separated from the wall surface 24.

As shown in FIG. 1, the pipe body 27 is communicated with a head lubrication passage 29 provided in the cylinder head 13, and the oil 17 passing through the main oil supply passage 22 passes through this head lubrication passage 29. , Camshaft,
It is designed to be guided by journals. The form of lubrication of the camshaft, journal, etc. in the cylinder head 13 is called mixed lubrication, and the crankshaft,
This is different from the lubrication form of the piston. In the cylinder head 13, the oil temperature when the friction of the oil 17 is minimum is lower than the oil temperature when the friction is minimum in the cylinder block 12.

In the hole 23, air, which is one of substances having low thermal conductivity, is sealed in the annular space 31 around the passage forming member 26. This air constitutes a heat insulating layer 33 as heat insulating means, covers the entire main oil supply passage 22, and blocks heat transfer between the passage forming member 26 and the wall surface 24 of the hole 23.

An oil pump 42 is drivingly connected to the crankshaft of the engine 11. The discharge port of the oil pump 42 and the main oil supply passage 22 are connected by a supply passage 39, and the oil 17 discharged from the pump 42 is supplied to the supply passage 39 and the main oil supply passage 2.
It is supplied to each part of the lubrication section via 2.

In order to guide the oil 17 in the main oil pan 14 to the oil pump 42, a main oil strainer 35 is arranged at the inner bottom portion of the main oil pan 14, and from the strainer 35, a main oil introduction passage 36 is provided. Is extended. Similarly, in order to guide the oil 17 in the sub oil pan 16 to the oil pump 42, the sub oil strainer 37 is arranged at the inner bottom portion of the sub oil pan 16, and the sub oil introduction passage 38 is provided from the strainer 37. Is extended. In both the main and sub oil strainers 35, 37, the oil 17 in the oil pans 14, 16 is introduced into the oil introduction passage 36,
When sucked into 38, the foreign matter mixed in the oil 17 is captured. In addition, the oil strainers 35, 37
The foreign matter not captured in (1) is captured by an oil filter (not shown) provided in the lubrication path.

The main oil introducing passage 36 and the sub oil introducing passage 38 are connected to a thermostat 41 as a temperature switching means.
It is connected to the suction port of the oil pump 42 via.
The thermostat 41 is for switching between the two introduction passages 36, 38 according to the temperature of the oil 17. More specifically, the thermostat 41 opens the auxiliary oil introduction passage 38 and closes the main oil introduction passage 36 when the temperature of the oil 17 is low. Further, the thermostat 41 opens the main oil introduction passage 36 and closes the sub oil introduction passage 38 when the temperature of the oil 17 is high. In other words, due to the switching operation of the thermostat 41, the sub oil pan 16 and the main oil supply passage 22 are brought into communication via the sub oil introduction passage 38 and the supply passage 39 when the oil 17 is at a low temperature. At a high temperature, the main oil pan 14 and the main oil supply passage 22 are connected to each other between the main oil introduction passage 36 and the supply passage 3.
The communication is established via 9.

An oil cooler 43 as an oil cooling means is arranged in the main oil introducing passage 36, that is, between the main oil strainer 35 and the thermostat 41. The oil cooler 43 is for preventing the temperature of the oil 17 from rising excessively, and cools the oil 17 circulated through the main oil pan 14 and the main oil supply passage 22 by the oil pump 42.

The cylinder block 12 and the cylinder head 13 are provided with return passages for guiding all the oil (return oil 44) from the lubrication portion of each moving part to the sub oil pan 16. A plate 45 which is a part of the return passage and which receives and collects the return oil 44 is disposed in the middle of the return passage and above the sub oil pan 16. At the center of the bottom portion of the plate 45, a conduit 46 for collecting the return oil 44 accumulated on the plate 45 and guiding it to the sub oil pan 16 is provided so as to project downward.

The plate 45 and the sub oil pan 16 are connected by an oil passage 47, and a heat retaining tank 48 is arranged in the middle of the oil passage 47. The heat-retaining tank 48 is for temporarily storing the high-temperature return oil 44 during operation of the engine 11 in preparation for the next start of the engine 11, while maintaining the temperature. The heat retaining tank 48 is formed such that its capacity is slightly larger than the capacity of the sub oil pan 16.

Both the plate 45 and the heat insulation tank 48 are connected to each other in order to connect or disconnect the communication.
An electromagnetic switching valve 49 is provided in the oil passage 47 between the valves 5 and 48. Similarly, the heat insulation tank 48 and the auxiliary oil pan 16
An electromagnetic switching valve 51 is also provided in the oil passage 47 between the both 48 and 16 in order to connect or disconnect the communication between them. The opening and closing of both electromagnetic switching valves 49 and 51 are drive-controlled by a controller (not shown). For example,
If the oil temperature is lower than a predetermined value when the engine 11 is started, both electromagnetic switching valves 49 and 51 are opened, and the engine 1
When 1 is stopped, both electromagnetic switching valves 49 and 51 are closed.

Next, the operation and effect of this embodiment constructed as described above will be described with reference to the graphs of FIGS. 2 (a) and 2 (b). When the engine 11 is started in a cold state (at the time of cold start), each part (cylinder block 12,
The temperature of the cylinder head 13 and the like) and the oil temperature are low, and the electromagnetic switching valves 49, 51 are opened. Engine 1
Oil 17 stored during operation of No. 1 and kept at high temperature
Flows into the sub oil pan 16 through the oil passage 47. The auxiliary oil introduction passage 38 is opened by the thermostat 41. The oil 17 in the sub oil pan 16 is sucked by the operation of the oil pump 42, and the sub oil strainer 3
The oil is supplied to the main oil supply passage 22 through the auxiliary oil introduction passage 38 and the supply passage 39 in order. A part of the oil 17 is guided to the head lubrication path 29 in the cylinder head 13 and supplied to the lubrication portion of the moving parts such as the camshaft. A part of the oil 17 is part of the cylinder block 1.
It is supplied to the lubrication part of moving parts such as pistons, crankshafts, etc. through the oil passages 25 in 2. The oil (return oil 44) that has passed through these lubrication portions passes through the return passage, is received by the plate 45, flows down from the conduit 46 into the sub oil pan 16, and is again returned to the oil pump 42.
Is sucked by The oil 17 circulates in the engine 11 through such a route.

At this time, since the capacity of the auxiliary oil pan 16 is small, a small amount of oil 17 circulates in the engine 11. Here, assuming that the amount of heat generated by the operation of the engine 11 is constant, the oil per unit amount is smaller than when the large amount of oil 17 in the main oil pan 14 is constantly circulated without providing the sub oil pan 16. The amount of heat transferred to 17 increases and the oil temperature easily rises.

Further, unlike the prior art, the sub oil pan 16 is shielded from the outside air, and the hot blow-by gas 21 comes into contact with the outer surface 16a thereof. The sub-oil pan 16 is not directly exposed to the outside air, and the oil 17 in the oil pan 16 is unlikely to be affected by the outside air temperature. The heat of the blow-by gas 21 passes through the auxiliary oil pan 16 and the oil 17 stored there.
Is transmitted to Further, since the main oil supply passage 22 is covered with the heat insulating layer 33 of air having a lower thermal conductivity than the metal material forming the cylinder block 12, heat exchange with the cylinder block 12 is hard to be performed. In other words, the heat of the oil 17 is not easily absorbed by the low temperature cylinder block 12. Therefore, the oil 17 circulating in the engine 11 is not only efficiently warmed, but also
The heat of the oil 17 is hard to be released.

As a result, immediately after the cold start, even if the running wind accompanying the running of the vehicle hits the main oil pan 14,
As shown in (a), the oil temperature THB in the cylinder block 12 and the oil temperature THH in the cylinder head 13 both rapidly rise and reach the temperature at which the friction is minimized in a short time. When the oil 17 flows through the head lubricating path 29, the heat of the oil 17 is taken by the cooling water flowing inside the cylinder head 13. Therefore, the temperature reached by the oil 17 is lower than the temperature reached by the oil 17 in the cylinder block 12.

On the other hand, when the temperature of the engine 11 is high, the oil temperature is high, and the thermostat 41 causes the main oil introducing passage 36
Is released. The oil 17 in the main oil pan 14 is supplied to the main oil supply passage 22 through the main oil strainer 35, the main oil introduction passage 36, and the supply passage 39 in order. A part of this oil 17 flows through the head lubrication path 29 in the same manner as when the temperature is low, and is supplied to the lubrication portion of the moving parts such as the camshaft. In addition, the oil 17
Part of the oil passes through the oil passage 25 and is supplied to the lubricating portion of the moving parts such as the piston and the crankshaft. The return oil 44 that has passed through these lubrication portions is received by the plate 45 in the process of passing through the return passage, and flows down from the conduit 46 into the sub oil pan 16. Since the oil 17 is not sucked from the sub oil strainer 37, the storage amount of the oil 17 gradually increases. This oil 17 eventually overflows from the sub oil pan 16, flows into the main oil pan 14, and is again sucked by the oil pump 42. The oil 17 circulates in the engine 11 through such a route.

During this circulation, the main oil supply passage 22 is covered with the heat insulating layer 33 for air, so that the heat of the oil 17 flowing through the passage 22 is hard to be released and the engine 1
The temperature of the oil 17 circulating in 1 rises. But,
The oil 17 is cooled when passing through the oil cooler 43 in the middle of the main oil introducing passage 36, and is prevented from rising excessively. Therefore, after a certain amount of time has passed since the engine 11 was started, the oil temperatures THB and THH are maintained at the temperatures at which the friction is minimized, as shown in FIG.

When the oil 17 flows through the head lubrication path 29, the heat of the oil 17 is removed by the cooling water flowing in the cylinder head 13 as described above. Therefore, the oil 17 is kept at a lower temperature than the oil 17 in the cylinder block 12.

When the engine 11 is stopped, both electromagnetic switching valves 49 and 51 are closed. Then, the return oil 44 is stored in the heat retention tank 48, and is kept at a high temperature in preparation for the next engine start.

As described above, the friction caused by the oil 17 can be reduced even when the engine 11 is started in the cold state and when a certain amount of time has elapsed after the start. Further, since the temperature of the oil 17 flowing through the head lubrication path 29 also rises quickly, the temperature of the cylinder head 13 itself also rises at an early stage, fuel atomization is promoted, and emissions are reduced and fuel consumption is improved. It is valid.

Further, in this embodiment, the heat retaining tank 4 is previously prepared.
The oil 17 stored in the engine 8 is supplied to the sub oil pan 16 when the engine 11 is cold started.
Therefore, even at the cold start, the oil 17 having a high temperature and a low viscosity can be circulated immediately after the cold start.

In addition to this, the heat of the cooling water is less likely to be taken by the oil 17 and released to the outside air, so that the cooling water temperature T immediately after the cold start as shown in FIG. 2 (a).
HW also rises rapidly. Therefore, the performance of the heater that uses the heat of the cooling water can be improved. Further, the heat insulating layer 33 is formed by air enclosed between the hole 23 of the cylinder block 12 and the passage forming member 26. Since the heat insulating layer 33 is formed with such a very simple structure, it can be manufactured at low cost.

The present invention can be embodied in another embodiment shown below. (1) In the above-described embodiment, the sub oil pan 16 is arranged above the oil surface 19 so that the sub oil pan 16 does not come into contact with the oil 17 in the main oil pan 14.
It may be changed as shown in. That is, the outer member 52 that immerses the sub oil pan 16 in the oil 17 in the main oil pan 14, and the small-capacity inner member 5 that stores the oil 17
3 and 3. The inner member 53 is disposed inside the outer member 52, and the spacer 54 is interposed between the two members 53 and 52. In this way, the outer member 52 and the inner member 53
The blow-by gas 21 can pass between them. Therefore,
Similar to the above embodiment, the oil 1
The heat of 7 is difficult to be released to the outside air. Moreover, since the blow-by gas 21 contacts the outer surface 16a of the inner member 53, the oil temperature can be raised rapidly.

(2) As the heat insulating means,
Besides the heat insulating layer 33 made of air, the cylinder block 1
A material that is less likely to transfer heat than 2 can be used.
Such a material is not limited to gas and may be liquid or solid.

(3) Insulation tank 4 in the above embodiment
8. The electromagnetic switching valves 49 and 51 may be omitted. that's all,
Although the respective embodiments of the present invention have been described, technical ideas other than the claims that can be understood from the respective embodiments will be described below together with their effects.

(A) In the lubricating device according to the first aspect of the present invention, the main oil supply passage is formed by a tubular passage constituting member arranged in a hole opened in the cylinder block, and the heat insulating means is provided in the hole and the passage. A lubricating device for an internal combustion engine, which comprises air enclosed in an annular space between the constituent members. With such a structure, the heat insulating means can be formed with a very simple structure.

(B) In the lubricating device according to the first aspect of the present invention, further, a heat retaining tank for storing a part of the oil while keeping the oil at a high temperature while the internal combustion engine is stopped, a heat retaining tank and a sub tank when the internal combustion engine is started at a low temperature. A lubricating device for an internal combustion engine, which is provided with a switching valve that brings an oil pan into a communicating state. With such a configuration, it is possible to circulate high-temperature, low-viscosity oil immediately after the internal combustion engine is started.

(C) The lubricating device for an internal combustion engine according to claim 1, wherein the sub oil pan is disposed above an oil level of the main oil pan. With such a structure, the blow-by gas can be brought into contact with the outer surface of the sub oil pan with a simple structure.

[0043]

As described above in detail, in the present invention, the main oil supply passage in the cylinder block is covered with the heat insulating means, and the auxiliary oil pan having a smaller capacity than the main oil pan is provided in the crank chamber. Therefore, it is possible to suppress the heat of the oil from being released to the outside air or taken by the cylinder block at a low temperature such as a cold start of the internal combustion engine, and to reliably raise the oil temperature in a short time. it can.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an engine lubrication device.

2A and 2B are graphs showing changes with time of oil temperature and cooling water temperature.

FIG. 3 is a partial sectional view of a main oil supply passage.

FIG. 4 is a schematic configuration diagram showing another embodiment of the arrangement position of the sub oil pan.

[Explanation of symbols]

11 ... Gasoline engine as internal combustion engine, 12 ... Cylinder block, 14 ... Main oil pan, 15 ... Crank chamber, 16 ... Sub oil pan, 17 ... Oil, 22 ... Main oil supply passage, 33 ... Air constituting heat insulating means Insulation layer,
36 ... Main oil introduction passage, 38 ... Sub oil introduction passage, 4
DESCRIPTION OF SYMBOLS 1 ... Thermostat as temperature switching means, 42 ... Oil pump, 43 ... Oil cooler as oil cooling means, 44 ... Return oil, 45 ... Plate which comprises a part of return passage.

Claims (1)

[Claims] 1. A main oil pan attached to a lower surface of a cylinder block of an internal combustion engine, an auxiliary oil pan smaller than a capacity of the main oil pan and arranged in a crank chamber of the internal combustion engine, and an inside of the cylinder block. A main oil supply passage provided with a heat insulating means, an oil pump for supplying oil to each part of the lubricating part of the internal combustion engine through the main oil supply passage, and a return oil from the lubricating part of the internal combustion engine. A return passage for guiding the oil in the sub oil pan, a main oil introducing passage for guiding the oil in the main oil pan to the oil pump, and an oil cooling device for cooling the oil provided in the middle of the main oil introducing passage. Means, a sub oil introduction passage for guiding the oil in the sub oil pan to the oil pump, the main oil introduction passage, and the sub oil. Introducing passage lubrication system for an internal combustion engine, characterized in that connected to the oil pump via the temperature switching means for switching both said passage in accordance with the temperature of the oil and.