JPH08200028A - Lubricating device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Object] The present invention independently has a main lubrication system that lubricates sliding parts around a piston and a cylinder, and a sub-lubrication system that lubricates sliding parts of a valve train. An object of the present invention is to automatically prevent seizure of a valve mechanism due to a shortage of lubricating oil in a sub-lubrication system in a lubricating device for an internal combustion engine. [Composition] A communication passage 30 that connects the main lubrication system and the sub-lubrication system so that lubricating oil is supplied from the main lubrication system to the sub-lubrication system, and a closing valve 31 disposed in the communication passage.
And a lubricating oil amount detecting means 41 for detecting the amount of lubricating oil in the sub-lubricating system, and when it is determined that the amount of lubricating oil in the sub-lubricating system detected by the lubricating oil amount detecting means is below a predetermined value, A closing valve opening degree control means 40 for controlling the opening degree of the closing valve 31 so that a desired amount of lubricating oil in the main lubricating system is supplied to the sub lubricating system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine having a main lubrication system for lubricating a sliding portion around a piston and a cylinder and a sub-lubrication system for lubricating a sliding portion of a valve mechanism independently. The lubrication device.

[0002]

2. Description of the Related Art Optimum lubricating oil differs between a fluid-lubricated piston and a valve operating mechanism in which boundary lubrication is performed around a cylinder, and the lubricating oil used around a piston and a cylinder that has a high temperature has a thin viscous oil film. It has been found that when used for lubrication of the sliding portion of the valve mechanism, the sliding portion is considerably worn. In order to solve this problem, Japanese Utility Model Laid-Open No. 58-6908 discloses a main lubrication system that lubricates a sliding portion around a piston and a cylinder and a sub-lubrication system that lubricates a sliding portion of a valve mechanism. A lubricating device for an internal combustion engine is described, which is independent of each other.

Lubricating oil used in the sub-lubricating system does not reach such a high temperature and is not mixed with blow-by gas, so that it is very unlikely to deteriorate and it is necessary to replace it by the life of the vehicle. Therefore, in the above-mentioned prior art, a mechanism for replacing and replenishing the lubricating oil is not provided.

[0004]

However, the lubricating oil of the sub-lubricating system may be consumed by a phenomenon called oil falling that leaks from the valve stem seal into the combustion chamber and burns. Continuing operation without knowing that the valve mechanism may seize due to lack of lubricating oil.

Therefore, an object of the present invention is to provide a main lubrication system for lubricating a sliding portion around a piston and a cylinder,
In a lubricating device for an internal combustion engine, which independently has a sub-lubrication system for lubricating a sliding portion of a valve mechanism, seizure of the valve mechanism due to insufficient lubricating oil in the sub-lubrication system is automatically prevented.

[0006]

In order to achieve the above-mentioned object, a lubricating device for a first internal combustion engine according to the present invention comprises a main lubricating system for lubricating a sliding portion around a piston and a cylinder, and a valve operating valve. In a lubricating device for an internal combustion engine, which independently has a sub-lubrication system for lubricating a sliding portion of a mechanism, a lubricating oil is supplied from the main lubrication system to the sub-lubrication system for the main lubrication system and the sub-lubrication system. Communication passage, the closing valve disposed in the communication passage, the lubricating oil amount detecting means for detecting the lubricating oil amount in the sub-lubrication system, and the lubricating oil amount detecting means. When it is determined that the amount of lubricating oil in the sub-lubrication system is less than or equal to a predetermined value, the opening degree of the closing valve is adjusted so that a desired amount of lubricating oil in the main lubrication system is supplied to the sub-lubrication system. Control closing valve Degree control means, characterized by including the capital.

A second lubricating system for an internal combustion engine according to the present invention is, in the lubricating system for the first internal combustion engine, a deterioration degree detecting means for detecting a deterioration degree of lubricating oil in the main lubricating system, A closing valve opening prohibiting means for prohibiting the closing valve opening control means from opening the closing valve when the deterioration degree of the lubricating oil detected by the deterioration degree detecting means is on the deterioration side of a predetermined boundary value; It is characterized by including.

A third lubricating system for an internal combustion engine according to the present invention is the same as the lubricating system for the first internal combustion engine described above, for supplying lubricating oil to each sliding portion provided in the main lubricating system. A lubricating oil pressure sending means and a lubricating oil pressure detecting means for detecting a lubricating oil pressure downstream of a connecting portion of the communication passage in the main lubricating system are provided, and the closing valve opening control means is the lubricating oil pressure detecting means. The opening degree of the closing valve is controlled so that a desired amount of lubricating oil in the main lubricating system is supplied to the sub-lubricating system without the lubricating oil pressure detected by the hydraulic pressure falling below a predetermined hydraulic pressure. And

A fourth lubricating system for an internal combustion engine according to the present invention is the lubricating system for a first internal combustion engine as described above, wherein the main lubricating system is lubricated to supply lubricating oil to each sliding portion. A hydraulic pressure feeding means, an oil pan for storing lubricating oil, a relief passage connecting the downstream side of the lubricating hydraulic pressure feeding means and the oil pan, and a relief means arranged in the relief passage for controlling the lubricating oil pressure. The communication passage is provided and is connected to the relief passage downstream of the relief passage in the main lubrication system.

[0010]

In the first internal combustion engine lubrication device described above, the main lubrication system that lubricates the sliding portion around the piston and the cylinder and the sub-lubrication system that lubricates the sliding portion of the valve mechanism are independent of each other. In a lubricating device for an internal combustion engine that has, when it is determined that the amount of lubricating oil in the sub-lubrication system detected by the lubricating oil amount detecting means is less than or equal to a predetermined value, The sub-lubrication system is opened by controlling the opening degree by opening the closing valve arranged in the communication passage that communicates so that the lubricating oil is supplied from the main lubrication system to the sub-lubrication system. Make sure that the lubrication system is replenished.

Further, the above-described second internal combustion engine lubricating device is the same as the above-described first internal combustion engine lubricating device, wherein the closing valve opening prohibiting means is the deterioration degree of the lubricating oil detected by the deterioration degree detecting means. Is on the deterioration side of the predetermined boundary value, the opening of the closing valve by the closing valve opening control means is prohibited so that the deteriorated lubricating oil in the main lubricating system is not supplied to the sub lubricating system.

Further, the above third lubricating system for an internal combustion engine is the same as the lubricating system for the first internal combustion engine, in which the closing valve opening control means is used in the main lubricating system detected by the lubricating oil pressure detecting means. The opening of the closing valve is controlled so that the lubricating oil pressure on the downstream side of the connecting portion of the communication passage does not fall below the predetermined oil pressure, and the desired amount of lubricating oil in the main lubricating system is replenished to the sub-lubricating system, At this time, the lubricating oil pressure on the downstream side of the connecting portion of the communication passage in the main lubricating system is maintained at a predetermined oil pressure or higher.

Further, the above-mentioned fourth lubricating apparatus for an internal combustion engine is the same as the lubricating apparatus for the first internal-combustion engine, wherein the communication passage is a lubricating oil for supplying lubricating oil to each sliding portion in the main lubricating system. Even when supplying the lubricating oil from the main lubrication system to the sub-lubrication system, the main lubrication system is connected because it is connected to the downstream side of the relief mechanism in the relief passage that connects the downstream side of the hydraulic pressure feeding means and the oil pan that stores the lubricating oil. The lubricating oil pressure of the system is maintained at the lubricating oil pressure controlled by the relief means.

[0014]

1 is a system diagram showing a lubricating device for an internal combustion engine according to the present invention. In the figure, 10 is a main lubrication system that lubricates the sliding parts around the piston and the cylinder, and 20 is a sub-lubrication system that lubricates the sliding parts of the valve operating mechanism. In the internal combustion engine lubrication device, the sliding portion around the piston and the cylinder and the sliding portion of the valve operating mechanism are independently lubricated,
A lubricating oil suitable for each sliding part can be used. For example, it is possible to use a lubricating oil containing a friction modifier, such as a Mo-based lubricating oil, which cannot be used around the piston and cylinder where the temperature becomes high and blow-by gas mixes in the sliding part of the valve mechanism. Good lubrication of this sliding portion where the oil film becomes thin can be realized.

Explaining the main lubricating system 10, the lubricating oil in the oil pan 11 provided under the crankcase is an oil strainer 12 for removing large foreign matters.
Through the oil pump 13 through the oil filter 14
Pumped to. The lubricating oil from which fine foreign substances have been removed by the oil filter 14 is sent into the block jacket 15, and then supplied to the crankshaft 16, the connecting rod 17, the piston and the cylinder 18, and after lubricating them, the oil pan Returned to 11.
In order to prevent excessive pressurization of the lubricating oil by the oil pump 13, the valve is opened when the pressure immediately upstream of the oil filter 14 becomes equal to or higher than the predetermined pressure suitable for supplying the lubricating oil to the above-mentioned sliding portions. A relief valve 19 for returning excess lubricating oil to the oil pan 11 is provided.

Further, the sub-lubrication system 20 pumps the lubricating oil in the sub-oil pan 21 to the camshaft journal 23 and the camshaft gear 24 by the sub-oil pump 22 and then to the camshaft gear 24 to lubricate it. The lubricating oil is returned to the sub oil pan 21, and is pumped to the camshaft journal 23, and the lubricating oil that lubricates it is then cam 25, valve lifter and valve stem 26, camshaft gear 27, and fuel pump. 28, and after lubricating them, they are returned to the sub oil pan 21. In order to prevent excessive pressurization of the lubricating oil by the sub oil pump 22, the valve is opened when the predetermined pressure suitable for supplying the lubricating oil to each of the above-mentioned sliding parts is exceeded, and excess lubricating oil is removed from the sub oil pan. A relief valve 29 for returning to 21 is provided.

In this embodiment, the block jacket 15 and the crankshaft 16 in the main lubrication system 10
And a sub oil pan 21 of the sub lubrication system 20 are communicated with each other by a communication passage 30, and a closing valve 31 for closing the communication passage 30 is arranged in the communication passage 30. FIG. 2 is a diagram for explaining the opening control of the closing valve 31. The opening degree of the closing valve 31 arranged in the communication passage 30 is controlled by a driving device such as a step motor 32 based on a command from the control device 40. The control device 40 includes a lubricating oil amount detection sensor 41 for detecting the amount of lubricating oil in the sub oil pan 21 of the sub lubricating system 20, and a main lubricating system 2
The pressure sensor 42 for detecting the lubricating oil pressure in the lubricating oil passage between the block jacket 15 and the crankshaft 16 at 0, and the deterioration degree of the lubricating oil of the main lubricating system 10 are integrated from the time of lubricating oil replacement. An odometer 43 for measuring the mileage and a cooling water temperature sensor 44 are connected to the input side, and the output side thereof has considerably deteriorated the lubricating oil of the step motor 32 and the main lubrication system 10. A display 33 for notifying the driver of the is connected.

The lubricating oil in the sub-lubricating system 20 may be consumed due to the oil falling, and it may be consumed for a very long time (5 to 5).
After 6 years of use, a shortage of lubricating oil occurs, and operating without knowing this may cause the valve train to seize. In order to prevent this, the control device 40 described above controls the opening degree of the closing valve 31 according to the flowchart shown in FIG.
This flowchart is executed, for example, every time the engine is started.

First, at step 101, it is judged if the cooling water temperature THW detected by the cooling water temperature sensor 44 is equal to or lower than a predetermined water temperature THW1. When this judgment is denied, the engine stop time is short and the sub-lubrication system 2
Since there is a possibility that the lubricating oil in 0 has not been sufficiently collected in the sub oil pan 21, the processing ends. When the determination in step 101 is affirmative, step 1
Proceeding to 02, the present lubricating oil amount L in the sub oil pan 21 detected by the lubricating oil amount detection sensor 41 has a certain margin against the lack of lubricating oil that causes seizure in the valve mechanism. It is determined whether the amount is equal to or less than the predetermined amount L1. When this determination is denied, there is a sufficient amount of lubricating oil in the sub-lubrication system 20, and the process ends.

On the other hand, when the determination in step 102 is affirmative, the routine proceeds to step 103, where the current lubricating oil amount L in the sub oil pan 21 detected by the lubricating oil amount detecting sensor 41 causes the valve operating mechanism to seize. It is determined whether or not the amount is equal to or less than the second predetermined amount L2 immediately before waking up. When this judgment is affirmed, the routine proceeds to step 104, where the closing valve 3
1 is opened, and the pressure sensor 42 monitors the lubricating oil pressure in the lubricating oil passage between the block jacket 15 and the crankshaft 16 in the main lubricating system 10,
The opening degree of the lubricating oil pressure is controlled so that the lubricating oil pressure does not fall below a pressure at which the lubricating oil can be sufficiently supplied to each sliding portion of the main lubricating system 10, and the main lubricating system 10 is connected via the communication passage 30.
The lubricating oil in the sub-lubrication system 20 is replenished.
The lubrication oil in the sub-lubrication system 20 is maintained until the initial amount L3 is reached.

On the other hand, when the determination in step 103 is negative, the amount of lubricating oil in the sub-lubrication system 20 has decreased, but it has not yet reached the point where immediate refueling is required, so the routine proceeds to step 105, where the vehicle runs. It is determined whether or not the cumulative traveling distance D measured by the distance meter 43 after the lubricating oil of the main lubrication system 10 is changed is equal to or greater than the first predetermined distance D1. When this determination is affirmed, the lubricating oil of the main lubrication system 10 has a low degree of deterioration and is sufficiently suitable for replenishment to the sub-lubrication system 20, so the routine proceeds to step 104, where the sub-lubrication system 20 is Replenishment of lubricating oil is executed, but when the determination in step 105 is negative, this replenishment is not executed and step 106 is executed.
Then, it is judged whether or not the integrated travel distance D is equal to or more than the second predetermined distance D2 indicating the time for replacing the lubricating oil in the main lubrication system 10. If this judgment is denied, the processing is ended as is, but affirmed. When it is necessary to proceed to step 107, the indicator 33 is turned on to prompt the driver to replace the lubricating oil in the main lubricating system 10.

As described above, the current predetermined amount L of lubricating oil in the sub oil pan 21 has a certain margin against the lack of lubricating oil that may cause seizure in the valve mechanism.
If it is 1 or less, but is not equal to or less than the second predetermined amount L2 immediately before the valve mechanism is seized, the deteriorated main lubricating system 10 is not replenished with lubricating oil and the main lubricating system 10 is lubricated. It is designed to replenish after waiting for oil change.

The second predetermined amount L immediately before the lubricating oil of the sub-lubrication system 20 is seized in the valve mechanism due to the oil drop.
It usually takes 5 to 6 years to be consumed, whereas the replacement interval of the lubricating oil in the main lubricating system 10 is about 1 year, so such replenishment is sufficient for seizing the valve mechanism. Although it can be prevented, if the amount of lubricating oil in the sub-lubricating system 20 decreases to the second predetermined amount L2 just before the seizure of the valve operating mechanism before the replacement of the lubricating oil in the main lubricating system 10, it deteriorates. However, the lubricating oil of the main lubrication system 10 is replenished to the sub-lubrication system 20 to prevent seizure of the valve mechanism.

FIG. 4 is a system diagram showing another embodiment of the present invention. The difference from FIG. 1 is that the communication passage 30 ′ is connected to the downstream side of the relief valve 19 of the main lubrication system 10. It is that you are. Replenishment of the lubricating oil from the main lubricating system 10 to the sub-lubricating system 20 is performed in the same manner as in the above-described embodiment, except that the lubricating oil at this position in the main lubricating system 10 is simply returned to the oil pan 11. So to speak
It is an excessive amount to lubricate each sliding portion of the main lubrication system 10, and when it is necessary to replenish the sub-lubrication system 20 with lubrication oil, it is not necessary to monitor the lubrication oil pressure of the main lubrication system 10. The closing valve 31 may be fully opened. Close valve 31
If the relief valve 19 is not opened even if is opened, the lubricating oil is not supplied from the main lubrication system 10 to the sub-lubrication system 20, but the oil pump 13 is driven in synchronization with the crankshaft. Therefore, the relief valve 19 is reliably opened at the time of high engine speed, and at this time, the lubricating oil is reliably supplied to the sub-lubrication system 20.

FIG. 5 is a sectional view of the valve mechanism in the above-described two embodiments. In the figure, 50 is a cam, and 51 is a valve lifter that abuts the cam 50 via a shim 52. At the upper inside of the cap-shaped valve lifter 51, the valve 5 is urged in the valve opening direction by a spring 53.
The stem 54a of No. 4 is in contact. The recess 55 formed near the lower side of the valve lifter 51 of the cylinder head is a sub oil pan of the sub lubrication system. In the conventional case where the lubrication system was one system, a cap-shaped valve lifter 51 was used.
Lubrication at the contact portion with the valve stem 54a located inside of the valve allows the atomized lubricating oil to be guided into the valve lifter 51 by the blow-by gas when the blow-by gas is supplied to the intake air and passes near the valve lifter 51 of the cylinder head. However, when the lubrication system of the valve mechanism is a separate system as in the present invention, the low-friction lubricating oil used as the lubricating oil on the valve mechanism side is not deteriorated by blow-by gas. Not preferred, valve lifter 51
Blow-by gas cannot be used to guide the lubricating oil to the inside of the.

FIG. 6 is a cross-sectional view of the valve lifter 51. The lower portion of the cylindrical inner wall surface 51a has a valve stem 54.
inclined surface 51c at a predetermined angle θ toward the contact portion 51b with a
When the lubricating oil flowing down along the cylindrical outer wall surface 51d of the valve lifter reaches the lower part and enters the inner part,
As the valve lifter 51 moves up and down, the lubricating oil is blown by the inclined surface toward the contact portion 51b with the valve stem 54a, and the contact portion located inside the valve lifter 51, the entire valve stem, and the spring 53 are blow-by. Good lubrication can be achieved without using gas.

FIG. 7 shows a modification of the inclined surface 51c of FIG. 6, in which (A) shows a wedge-shaped groove 51 immediately above the inclined surface 51c.
e formed, (B) formed with an arcuate groove 51f above the inclined surface 51c, and (C) formed an inclined surface 51c '.
Since it protrudes inward from the cylindrical inner wall surface 51a, the lubricating oil that flows down along the cylindrical inner wall 51a of the valve lifter 51 is temporarily stored immediately above the inclined surfaces 51c and 51c '. Lubricating oil is splashed to the contact portion 51b with the valve stem 54a without interruption due to the inclined surface 51c, so that the above-described lubrication can be further ensured.

In the above-mentioned two embodiments, the communication passage is the oil pan 11 of the main lubrication system 10 and the sub-lubrication system 2.
No. 0 sub oil pan 21 is communicated with, and a pump for pumping the lubricating oil from the oil pan 11 of the main lubrication system 10 to the sub oil pan 21 of the sub lubrication system 20 is arranged in this communication passage. For example, the main lubrication system does not necessarily have to have an oil pump.

Further, in order to detect the degree of deterioration of the lubricating oil of the main lubrication system 10, the odometer 43 measures the total traveling distance after the lubricating oil is replaced, but this limits the present invention. Instead, it is possible to directly detect the degree of deterioration by, for example, an oil basicity sensor that detects the basicity of the lubricating oil, an oil acidity sensor that detects the acidity, or the like. Further, in the two embodiments described above, the main lubrication system 10 and the sub-lubrication system 20 are provided.
In order to optimize the oil viscosity of the above, for example, the sub-lubrication system 20 may be independently cooled so as to have a temperature lower than that of the main lubrication system 10.

[0030]

As described above, according to the first lubricating system for an internal combustion engine of the present invention, the main lubrication system that lubricates the sliding parts around the piston and the cylinder and the sliding parts of the valve train are lubricated. In a lubricating device for an internal combustion engine having an independent sub-lubrication system for performing the above, when the amount of lubricating oil in the sub-lubrication system detected by the lubricating oil amount detecting means is determined to be below a predetermined value, the closing valve is opened. Control means opens a closing valve arranged in a communication passage that connects the main lubrication system and the sub-lubrication system so that the lubricating oil is supplied from the main lubrication system to the sub-lubrication system, and controls the opening degree thereof. However, in order to supply the desired amount of lubricating oil to the sub-lubricating system, even if the lubricating oil in the sub-lubricating system is consumed due to oil drop, etc. To lubricate the main lubrication system There is replenished, it is possible to prevent the seizure of the valve operating mechanism.

Further, according to the above-described second internal combustion engine lubricating device, in the above-described first internal combustion engine lubricating device, the closing valve opening prohibiting means is provided with the lubricating oil detected by the deterioration degree detecting means. When the deterioration level is on the deterioration side of the predetermined boundary value,
In order to prohibit the opening of the closing valve by the closing valve opening control means, the lubricating oil is replenished to the sub-lubricating system only when the lubricating oil in the main lubricating system is not deteriorated. Lubrication in the system can be improved.

Further, according to the above-described third internal combustion engine lubricating device, in the above-described first internal combustion engine lubricating device, the closing valve opening control means is the main lubricating oil detected by the lubricating oil pressure detecting means. The opening degree of the closing valve is controlled so that the desired amount of lubricating oil in the main lubricating system is supplied to the sub-lubricating system without the lubricating oil pressure on the downstream side of the connection part of the communication passage in the system falls below a predetermined hydraulic pressure. At this time, in order to maintain the lubricating oil pressure on the downstream side of the connection part of the communication passage in the main lubricating system above the predetermined hydraulic pressure, even when the lubricating oil is supplied from the main lubricating system to the sub lubricating system, A sufficient amount of lubricating oil is supplied to each of the sliding parts to ensure good lubrication.

According to the fourth internal combustion engine lubricating device described above, in the first internal combustion engine lubricating device described above, the communication passage is connected to the relief passage of the main lubricating system downstream of the relief means. Therefore, even when replenishing the lubricating oil from the main lubricating system to the sub-lubricating system, the lubricating oil pressure in the main lubricating system is maintained at the lubricating oil pressure controlled by the relief means, and the sliding parts in the main lubricating system are Is supplied with sufficient amount of lubricating oil to ensure good lubrication.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a lubricating device for an internal combustion engine according to the present invention.

FIG. 2 is a configuration diagram near the communication passage of FIG.

FIG. 3 is a flowchart for closing valve opening control executed by a control device.

FIG. 4 is a system diagram showing another embodiment of a lubricating device for an internal combustion engine according to the present invention.

FIG. 5 is a sectional view of the vicinity of the valve.

FIG. 6 is a sectional view of a valve lifter.

FIG. 7 is a modification of the lower portion of the valve lifter.

[Explanation of symbols]

 10 ... Main lubrication system 20 ... Sub lubrication system 30, 30 '... Communication passage 31 ... Closure valve 40 ... Control device 41 ... Lubricating oil amount detection sensor 51 ... Valve lifter 51c, 51c' ... Inclined surface

Claims (4)

[Claims] 1. A lubricating device for an internal combustion engine, comprising: a main lubricating system for lubricating a sliding portion around a piston and a cylinder; and a sub-lubricating system for lubricating a sliding portion of a valve mechanism independently. A communication passage that connects the main lubrication system and the sub-lubrication system so that lubricating oil is supplied from the main lubrication system to the sub-lubrication system, a closing valve disposed in the communication passage, and a sub-lubrication system in the sub-lubrication system. The amount of lubricating oil for detecting the amount of lubricating oil in the sub-lubrication system detected by the lubricating oil amount detecting means is less than a predetermined value A closing device for controlling the opening degree of the closing valve so that the lubricating oil in the lubricating system is supplied to the sub-lubricating system, and a lubricating device for an internal combustion engine. 2. A deterioration degree detecting means for detecting a deterioration degree of the lubricating oil in the main lubrication system, and a deterioration degree of the lubricating oil detected by the deterioration degree detecting means on a deterioration side of a predetermined boundary value, 2. The lubricating device for an internal combustion engine according to claim 1, further comprising: a closing valve opening prohibiting unit that prohibits opening of the closing valve by the closing valve opening control unit. 3. Lubricating hydraulic pressure feeding means for supplying lubricating oil to each sliding portion provided in the main lubricating system, and lubricating oil pressure on the downstream side of the connecting portion of the communication passage in the main lubricating system are detected. Lubricating oil pressure detection means, the closing valve opening control means, the lubricating oil pressure detected by the lubricating oil pressure detection means does not fall below a predetermined oil pressure,
The lubricating device for an internal combustion engine according to claim 1, wherein the opening degree of the closing valve is controlled so that a desired amount of lubricating oil in the main lubricating system is supplied to the sub lubricating system. 4. The main lubrication system includes a lubricating oil pressure feeding means for feeding lubricating oil to each sliding portion, an oil pan for accumulating the lubricating oil, a downstream side of the lubricating oil pressure feeding means, and the oil pan. And a relief means arranged in the relief passage to control the lubricating oil pressure, and the communication passage is connected to a relief means downstream side of the relief passage in the main lubrication system. The lubrication device for an internal combustion engine according to claim 1, wherein: