JP2008286063A - Lubricating device for internal combustion engine - Google Patents

Abstract

An object of the present invention is to provide a lubricating device for an internal combustion engine that can prevent seizure of the internal combustion engine.
Lubricating oil stored in a storage means 51 is pressurized to a reference discharge pressure by a pressurizing means 55 and supplied to a supply target portion 53 of an internal combustion engine. According to the operating state of the internal combustion engine, the oil pressure of the lubricating oil circulating in the lubricating oil circulation system 52 can be reduced by a low hydraulic pressure setting means 80 capable of reducing the reference discharge pressure according to the rotational speed of the internal combustion engine, and the storage means 51. The oil amount detecting means 73 for detecting the amount of lubricating oil stored, and the low oil pressure setting means 80 are controlled when at least the oil amount detected by the oil amount detecting means 73 is not more than a preset oil amount threshold value. And a control means 70 capable of prohibiting the reduction of the hydraulic pressure.
[Selection] Figure 1

Description

  The present invention relates to an internal combustion engine lubrication device, and more particularly to an internal combustion engine lubrication device suitable for application to an internal combustion engine having a two-tank oil pan.

  Conventionally, lubricating oil (engine oil) has been used for lubricating and cooling internal combustion engines. In such a conventional internal combustion engine lubricating device, the lubricating oil stored in the oil pan is sucked out by the oil pump, and the lubricating oil is supplied to the lubricating oil supply target parts (for example, gears, cams) of each part of the internal combustion engine. Shaft, cylinder, journal, piston, lash adjuster, etc.). The lubricating oil, for example, forms an oil film at the supply target part to promote lubrication between the parts and prevent oxidation of the parts. After absorbing and cooling the heat, etc., it is returned (returned) to the oil pan provided below the crank chamber through the oil return passage by the action of gravity.

  As such a conventional internal combustion engine lubricating device, for example, an engine lubricating oil control device described in Patent Document 1 includes a hydraulic pressure changing means capable of changing a lubricating hydraulic pressure for lubricating each part of the engine, and an engine water temperature is predetermined. By controlling the lubricating oil pressure to be on the high pressure side when the water temperature rise rate is greater than the threshold value and lower than the threshold value, the lubricating oil pressure is on the low pressure side when the water temperature rise rate is below the threshold value. The amount of work in an oil pump driven in conjunction with an internal combustion engine is reduced to improve fuel efficiency.

JP-A-6-221127

  However, in the engine lubricating oil control device described in Patent Document 1 described above, for example, when the lubricating oil pressure circulating through each part of the engine is set to the low pressure side, the lubricating oil pressure is set to the low pressure side. Therefore, the amount of circulating oil circulating in the lubricating oil circulation system is also reduced. In this state, if the amount of lubricating oil stored in the oil pan is insufficient, air is sucked into the lubricating oil circulation system by the oil pump, which further reduces the circulating oil amount. There is a possibility that seizure may occur at the sliding portion.

  Accordingly, an object of the present invention is to provide a lubricating device for an internal combustion engine that can prevent seizure of the internal combustion engine.

  In order to achieve the above object, a lubricating device for an internal combustion engine according to the first aspect of the present invention pressurizes the lubricating oil stored in the storage means to the reference discharge pressure by the pressurizing means and supplies it to the supply target portion of the internal combustion engine. And the reference of the lubricating oil circulation system that can be collected in the storage means and the hydraulic pressure of the lubricating oil that circulates through the lubricating oil circulation system according to the rotational speed of the internal combustion engine, depending on the operating state of the internal combustion engine. Low oil pressure setting means that can be reduced from the discharge pressure, oil amount detection means for detecting the oil amount of the lubricating oil stored in the storage means, and at least the oil amount detected by the oil amount detection means is preset. And a control means capable of controlling the low oil pressure setting means and prohibiting the reduction of the oil pressure when the oil amount is equal to or less than an oil amount threshold value.

  According to a second aspect of the present invention, there is provided a lubricating device for an internal combustion engine, comprising: a hydraulic pressure detecting means for detecting a hydraulic pressure of the lubricating oil circulating in the lubricating oil circulation system; The reduction of the hydraulic pressure is prohibited when the hydraulic pressure is not more than a preset hydraulic pressure threshold.

  According to a third aspect of the present invention, there is provided a lubrication apparatus for an internal combustion engine, comprising: a rotational speed detection means for detecting a rotational speed of the internal combustion engine; A hydraulic pressure threshold is set.

  In the lubricating device for an internal combustion engine according to a fourth aspect of the present invention, the storage means is partitioned from a first storage section provided with a suction section for sucking the lubricating oil into the lubricating oil circulation system, and the first storage section. The oil amount detecting means detects the amount of the lubricating oil stored in the first storage portion.

  In the lubricating device for an internal combustion engine according to the invention according to claim 5, provided with communication means capable of communicating the first storage part and the second storage part in the lubricating oil stored in the second storage part, The control means controls the communication means to connect the first storage section and the second storage section when the low hydraulic pressure setting means is controlled to prohibit the reduction of the hydraulic pressure. .

  According to a sixth aspect of the present invention, there is provided a lubrication apparatus for an internal combustion engine comprising an inclination detection means for detecting an inclination of an oil surface of the lubricating oil stored in the storage means, wherein the control means is detected by the inclination detection means. The reduction of the hydraulic pressure can be prohibited by controlling the low hydraulic pressure setting means based on the inclination of the lubricating oil.

  In a lubricating device for an internal combustion engine according to a seventh aspect of the present invention, the supply target portion includes an injection means capable of injecting the lubricating oil toward a piston of the internal combustion engine.

  An internal combustion engine lubrication apparatus according to an eighth aspect of the invention is characterized in that the pressurizing means can be driven in conjunction with the internal combustion engine to pressurize the lubricating oil.

  In the lubricating device for an internal combustion engine according to the invention according to claim 9, the low hydraulic pressure setting means includes an introduction port into which a part of the lubricating oil circulating in the lubricating oil circulation system is introduced and the lubrication of the lubricating oil circulation system. A first oil chamber having a discharge port capable of discharging the lubricating oil upstream of the pressurizing unit with respect to the oil circulation direction; and the discharge port according to a hydraulic pressure of the lubricating oil in the first oil chamber. A first valve body that can be opened and closed, a second oil chamber that can introduce a part of the lubricating oil that circulates through the lubricating oil circulation system, and that can be discharged, and a second oil chamber A second valve body capable of regulating the opening and closing of the discharge port by the first valve body according to the oil pressure of the lubricant, the introduction of the lubricant into the second oil chamber via the introduction discharge port, and the And a switching portion capable of switching between discharge of the lubricating oil from the second oil chamber. .

  According to the lubricating device for an internal combustion engine according to the present invention, the reduction of the hydraulic pressure is prohibited based on the amount of the lubricating oil stored in the storage means, so that the internal combustion engine can be prevented from being seized.

  Embodiments of a lubricating device for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  1 is a schematic cross-sectional view of a lubricating device for an internal combustion engine according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view during oil relief of the lubricating device for an internal combustion engine according to a first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view at the time of low oil pressure control of the lubricating device for the internal combustion engine according to the first embodiment of the present invention, and FIG. 4 shows the engine speed in the lubricating device for the internal combustion engine according to the first embodiment of the present invention. FIG. 5 is a diagram showing the relationship between the oil amount threshold and FIG. 5 is a diagram showing the relationship between the engine speed and the oil pressure threshold in the lubricating device for an internal combustion engine according to the first embodiment of the present invention. FIG. 7 is a schematic sectional view of an engine to which a lubricating device for an internal combustion engine according to Embodiment 1 is applied. FIG. 7 is a schematic configuration diagram showing a lubricating oil circulation system of the lubricating device for the internal combustion engine according to Embodiment 1 of the present invention. .

  As shown in FIG. 6, in this embodiment, the internal combustion engine lubrication device 50 according to the present invention is applied to an engine 1 as an internal combustion engine. The engine 1 is an engine mounted on a vehicle such as a passenger car or a truck, and includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston 2 provided in the cylinder bore 3 so as to reciprocate is reciprocated twice. This is a so-called four-cycle engine that performs a series of four strokes.

  The engine 1 includes a cylinder bore 3 in which each piston 2 can reciprocate, a combustion chamber 5 provided on one side in the moving direction of the piston 2, and a crank chamber 4 provided on the other side in the moving direction of the piston 2. Here, the moving direction of the piston 2 is the axial direction of the cylinder bore 3 formed in a cylindrical shape. That is, the combustion chamber 5 is provided on one side in the axial direction of the cylinder bore 3 with the piston 2 in between, and the crank chamber 4 is provided on the other side. The engine 1 is a four-cylinder engine including four pistons 2, cylinder bores 3, crank chambers 4, and combustion chambers 5 each. However, the number of cylinders is an example and is not necessarily limited to four cylinders.

  Further, the engine 1 includes an intake port 6 and an exhaust port 7 communicating with the combustion chamber 5, an injector 8 capable of directly injecting fuel into the combustion chamber 5, and an air-fuel mixture located above the combustion chamber 5. A spark plug 9 that ignites and a crankshaft 10 that can rotate in conjunction with the reciprocating motion of the piston are provided. The engine 1 further includes a cylinder head 11, a cylinder block 12, and a two-tank oil pan 51 as a storage unit that forms a lubricating device 50 described later.

  The cylinder head 11 is fastened on the cylinder block 12, and the two-tank oil pan 51 is fastened to the lower part of the cylinder block 12. The cylinder block 12 has a cylindrical cylinder bore 3 formed therein. The cylinder block 12 has a bore wall surface 3a that forms a plurality of cylinder bores 3 and a crank chamber wall surface 4a that forms a plurality of crank chambers 4. The bore wall surface 3a and the crank chamber wall surface 4a are formed on the bore wall surface 3a. The lower end portion is continuous with the upper end portion of the crank chamber wall surface 4a.

  The piston 2 is fitted to the cylinder bore 3 so as to be movable up and down. The plurality of crank chambers 4 communicate with the plurality of cylinder bores 3 and are independently partitioned by a bulkhead 4b as a partition wall. More specifically, each crank chamber 4 includes a crank chamber wall surface 4a, a bulkhead 4b, a two-tank oil pan 51, a bottom surface 2b that is one end surface of the piston 2, and a bore wall surface 3a. Partitioned. That is, the volume of each crank chamber 4 changes due to the reciprocating motion of the piston 2, and when the piston 2 is located on the top dead center side (cylinder head 11 side), the internal space of the cylinder bore 3 is also part of it. included.

  The crankshaft 10 is provided so as to pass through the plurality of crank chambers 4 and the bulkhead 4b, and each piston 2 is connected to the crankshaft 10 via a connecting rod 17, respectively. The crankshaft 10 has a counterweight 10a around its axis. The reciprocating motion of each piston 2 is transmitted to the crankshaft 10 via the connecting rod 17, where it is converted into rotational motion and taken out as the output of the engine 1. In this engine 1, the crankshaft 10 and the counterweight 10a rotate clockwise as indicated by arrows in FIG.

  The combustion chamber 5 is provided on the opposite side of the crank chamber 4 with the piston 2 in between. A plurality of combustion chambers 5 are formed corresponding to the plurality of cylinder bores 3, and are defined by the lower surface 11 a of the cylinder head 11, the bore wall surface 3 a of the cylinder bore 3, and the top surface 2 a which is the other end surface of the piston 2. Two intake ports 6 and two exhaust ports 7 are formed in the upper portion of the combustion chamber 5, that is, in the lower surface 11 a of the cylinder head 11. An intake valve 14 and an exhaust valve 15 are provided at the openings of the intake port 6 and the exhaust port 7. The intake valve 14 and the exhaust valve 15 can open and close the intake port 6 and the exhaust port 7, respectively, and can connect the intake port 6 and the combustion chamber 5, and the combustion chamber 5 and the exhaust port 7, respectively. The intake port 6 is connected to an intake passage (intake pipe) 18 that introduces air upstream in the intake direction, and the exhaust port 7 is provided with an exhaust passage (exhaust pipe) 19 that discharges exhaust gas downstream in the exhaust direction. Connected.

  The injector 8 is attached to the intake port 6 side of the cylinder head 11. In addition, the injector 8 is provided with a tip inclined toward the center line of the cylinder bore 3 by a predetermined angle with respect to the vertical direction. The injector 8 injects fuel spray toward the top surface 2 a of the piston 2. The spark plug 9 is attached to the ceiling portion of the combustion chamber 5, that is, between the intake port 6 and the exhaust port 7 on the lower surface 11 a of the cylinder head 11.

  The engine 1 further supplies oil as lubricating oil stored in the two-tank oil pan 51 to a supply target portion 53 (for example, gear, camshaft, cylinder, journal, piston, lash adjuster, etc.) of each part of the engine 1. And a lubrication device 50 for supplying and lubricating. The lubricating device 50 supplies the two-tank oil pan 51 and the oil as lubricating oil stored in the two-tank oil pan 51 to the supply target portion 53 of the engine 1 and collects it again in the two-tank oil pan 51. A possible oil circulation system 52 (see FIG. 7) is included.

  The two-tank oil pan 51 is fastened to the lower portion of the cylinder block 12 as described above, and a baffle plate (not shown) is mounted therein to store oil as lubricating oil. Further, the two-tank oil pan 51 of the present embodiment includes an inner tank 51a as a first storage part and an outer tank 51b as a second storage part. The inner tank 51a is provided inside the outer tank 51b, and as shown in FIG. 1, an oil strainer 54 (described later with reference to FIG. 7) as a suction portion that sucks oil as lubricating oil into the oil circulation system 52 is provided. Provided. The outer tub 51b is separated from the inner tub 51a and communicates via a communication hole 51c having a relatively small communication area. The communication hole 51c controls the oil conduction between the inner tank 51a and the outer tank 51b by utilizing a change in the viscosity of the oil.

  Therefore, for example, at the time of cold start where the temperature of the oil is low and the viscosity is high, the oil stored in the inner tank 51a provided with the oil strainer 54 is mainly sucked into the oil circulation system 52 and easily circulated. The amount of oil circulating through the circulation system 52 is relatively small. For this reason, since the total amount of oil circulating through the oil circulation system 52 is relatively small, the temperature of the oil is easily raised early, and as a result, the warm-up property of the engine 1 can be improved.

  When the oil stored in the inner tank 51a is at a low temperature and has a high viscosity, the oil passage resistance when the oil having a high viscosity passes through the communication hole 51c in the communication hole 51c having a relatively small communication area. Therefore, mixing of oil between the inner tank 51a and the outer tank 51b is suppressed. On the other hand, when the oil temperature of the oil that is sucked into the oil circulation system 52 and circulated increases, the viscosity of the oil in the inner tank 51a gradually decreases, and this low viscosity oil passes through the communication hole 51c. As a result, the oil is mixed between the inner tank 51a and the outer tank 51b. As a result, the oil stored in the entire two-tank oil pan 51 is transferred from the oil strainer 54 to the oil circulation system 52. Inhaled and circulated. The two-tank oil pan 51 may not be configured to control oil conduction between the inner tank 51a and the outer tank 51b by the communication hole 51c having a relatively small communication area as described above. By providing a temperature control valve or the like in a communication hole having a normal size and controlling this temperature control valve according to the oil temperature, the communication between the inner tank 51a and the outer tank 51b, in other words, the outer tank You may make it control the flow of the oil from 51b to the inner tank 51a.

  As shown in FIG. 7, the oil circulation system 52 supplies the oil stored in the two-tank oil pan 51 to each part of the engine 1 through a plurality of pipes and passages, and then collects the oil in the two-tank oil pan 51. Configured as a system. In the lubricating device 50, the oil stored in the two-tank oil pan 51 is sucked out by an oil pump 55 as a pressurizing means, and the oil is supplied to the oil supply target portion 53 of each part of the engine 1 as lubricating oil or It is configured to be supplied as hydraulic oil. The oil has a lubricating action at the oil supply target portion 53 and absorbs heat such as friction heat from the oil supply target portion 53, and then enters the two-tank oil pan 51 provided below the crank chamber 4. Reflux.

  Specifically, the oil circulation system 52 is provided with an oil strainer 54, an oil pump 55, an oil filter 56, and a main gallery 57 as suction portions. The oil strainer 54 is provided in the inner tank 51a of the two-tank oil pan 51, and serves as a suction port for oil in the inner tank 51a. The oil pump 55 is driven as the crankshaft 10 rotates, sucks the oil in the two-tank oil pan 51 into the passage of the oil circulation system 52, and pressurizes the oil to a reference discharge pressure corresponding to the rotation speed of the crankshaft 10. It is to be pumped. The oil filter 56 is provided between the oil pump 55 and the main gallery 57, and removes foreign matters in the oil. The main gallery 57 extends in the wall surface of the cylinder block 12 along the crankshaft 10. The main gallery 57 is connected to an oil pump 55 through an oil filter 56, supplied with oil pressurized by the oil pump 55, and branches the supplied oil to the cylinder head 11 and the cylinder block 12. To supply.

  Therefore, the oil stored in the inner tank 51 a of the two-tank oil pan 51 is sucked out by the oil pump 55 through the oil strainer 54 into the passage of the oil circulation system 52, passed through the oil filter 56, and the reference to the main gallery 57. Pumped by discharge pressure. The oil pumped to the main gallery 57 branches to the cylinder head 11 and the cylinder block 12 via the main gallery 57 and is then supplied to each part of the engine 1. For example, in the cylinder block 12, the crankshaft journal 58, the crank pin 59, the connecting rod 17 and the like, and the hydraulic oil of the oil jet 60 as the injection means, the cylinder head 11 uses the lubricating oil such as the cam journal 61, the lash adjuster 62, and the VVT (variable valve mechanism). : Variable Valve Timing-intelligent) That is, here, the oil supply target portion 53 is the crankshaft journal 58, the crankpin 59, the connecting rod 17, the oil jet 60, the cam journal 61, the lash adjuster 62, and the VVT 63.

  Here, the oil jet 60 injects oil toward the bottom surface 2b of the piston 2 to cool the piston 2 that is exposed to the combustion gas and has a high thermal load. This prevents combustion and suppresses knocking. The VVT 63 is an intake / exhaust variable valve mechanism that controls the intake valve 14 and the exhaust valve 15 at an optimal opening / closing timing according to the operating state. The VVT 63 is configured by providing a VVT controller at the shaft end portions of the intake and exhaust camshafts and the exhaust camshaft, and the cam by operating the hydraulic pressure from the oil control valve on the advance angle chamber and the retard angle chamber of the VVT controller. By changing the phase of the camshaft with respect to the sprocket, the opening / closing timing of the intake valve 14 and the exhaust valve 15 can be advanced or retarded. The lash adjuster 62 has a high temperature in the engine body due to combustion in the combustion chamber 5, and the heat is transmitted to the VVT 63 so that the VVT 63 also becomes high temperature. In order to prevent this, the gaps between the constituent members in the VVT 63 are adjusted. The lash adjuster 62 is interposed between the constituent members that are displaced during the operation of the VVT 63 and uses the supplied oil as the working oil, thereby preventing the occurrence of a gap following the change in these intervals. In addition, the operating noise of the VVT 63 and the wear during operation can be reduced.

  Oil supplied to the cylinder block 12 and used as lubricating oil or hydraulic oil falls toward the two-tank oil pan 51 and is collected in the two-tank oil pan 51. On the other hand, the oil supplied to the cylinder head 11 and used as lubricating oil or hydraulic oil flows through the cylinder head 11 and then is discharged into an oil return passage (not shown), and drops in the oil return passage by the action of gravity. Similarly, it is returned into the two-tank oil pan 51.

  Further, as shown in FIG. 6, the lubricating device 50 includes an electronic control unit (ECU: Electronic Control Unit; hereinafter simply referred to as “ECU”) 70 as a control unit, and a crank angle sensor 71 as a rotation speed detection unit. A water temperature sensor 72 is provided as a cooling water temperature detecting means.

  The ECU 70 is configured around a microcomputer and controls each part of the engine 1, and a crank angle sensor 71 and a water temperature sensor 72 are electrically connected to each other. The crank angle sensor 71 detects the crank angle of each cylinder. The crank angle sensor 71 transmits the detected crank angle to the ECU 70. The ECU 70 determines the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke in each cylinder based on the received crank angle, and the engine 1 of the engine 1 Calculate the number of revolutions (rpm). Here, in other words, the engine speed corresponds to the rotational speed of the crankshaft 10, and as the rotational speed of the crankshaft 10 increases, the rotational speed of the crankshaft 10 and the engine rotational speed also increase. The water temperature sensor 72 is provided in the cylinder block 12 and detects the engine cooling water temperature of the engine 1, and transmits the detected engine cooling water temperature to the ECU 70.

  In addition to the crank angle sensor 71 and the water temperature sensor 72, the ECU 70 includes an intake air temperature sensor that detects the intake air temperature in the air cleaner, an accelerator sensor that detects the amount of depression of the accelerator pedal (accelerator opening), and a throttle valve. A throttle position sensor for detecting the opening of the engine, an air / fuel ratio sensor for outputting a signal corresponding to the rich / lean of the exhaust air / fuel ratio in the exhaust passage, an intake pipe pressure sensor for detecting the pressure in the intake passage downstream of the throttle valve, and Various sensors such as a fuel pressure sensor for detecting the fuel pressure in the fuel supply passage are connected as necessary. That is, the ECU 70 determines the fuel injection amount (fuel injection amount) based on engine operating conditions such as intake air amount, intake air temperature, intake pressure, throttle opening, accelerator opening, engine speed, engine cooling water temperature, etc. detected by various sensors. Time), injection timing, ignition timing, etc. are determined, and the injector 8 and spark plug 9 are driven to execute fuel injection and ignition.

  Further, the ECU 70 can control the VVT 63 (see FIG. 7) based on the engine operating state. That is, when the temperature is low, the engine is started, the engine is idling, or the load is light, the exhaust gas blows back to the intake port 6 or the combustion chamber 5 by eliminating the overlap between the closing timing of the exhaust valve 15 and the opening timing of the intake valve 14. Reduce the amount to enable stable combustion and improved fuel efficiency. Further, at the time of medium load, by increasing the overlap, the internal EGR rate is increased to improve the exhaust gas purification efficiency, and the pumping loss is reduced to improve the fuel consumption. Furthermore, at the time of high-load low-medium rotation, the closing timing of the intake valve 14 is advanced, thereby reducing the amount of intake air that blows back to the intake port 6 and improving the volume efficiency. At the time of high load and high rotation, the closing timing of the intake valve 14 is retarded in accordance with the rotational speed, so that the timing is adjusted to the inertial force of the intake air and the volume efficiency is improved.

  In the engine 1 configured as described above, when the piston 2 descends in the cylinder bore 3, air is sucked into the combustion chamber 5 through the intake passage 18 and the intake port 6 (intake stroke). The fuel injected from the injector 8 into the combustion chamber 5 is mixed to form an air-fuel mixture. The air-fuel mixture is compressed by the piston 2 ascending in the cylinder bore 3 through the intake stroke bottom dead center (compression stroke), and when the piston 2 approaches the vicinity of the compression stroke top dead center, the mixture is made into the air-fuel mixture by the spark plug 9. It is ignited, the air-fuel mixture burns, and the piston 2 is lowered by the combustion pressure (expansion stroke). The air-fuel mixture after combustion is released as exhaust gas through the exhaust port 7 and the exhaust passage 19 as the piston 2 rises again toward the top dead center of the intake stroke via the expansion stroke bottom dead center (exhaust stroke). . The reciprocating motion of the piston 2 in the cylinder bore 3 is transmitted to the crankshaft 10 via the connecting rod 17, where it is converted into a rotational motion and taken out as an output. As the shaft 10 further rotates due to the inertial force, the cylinder 10 reciprocates in the cylinder bore 3 as the crankshaft 10 rotates. By rotating the crankshaft 10 twice, the piston 2 reciprocates the cylinder bore 3 twice, and during this time, a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke are performed, and once in the combustion chamber 5. Explosion takes place.

  During this time, in the lubricating device 50 of the engine 1, the oil stored in the two-tank oil pan 51 is sucked out by the oil pump 55 in the oil circulation system 52, and the oil is discharged to the engine via the main gallery 57. 1 is supplied to the oil supply target portion 53 of each part, and the oil performs a lubricating action in the oil supply target portion 53 and absorbs heat such as frictional heat from the oil supply target portion 53, and then the oil is cranked. It returns (returns) into a two-tank oil pan 51 provided below the chamber 4.

  Here, as shown in FIGS. 1, 2, and 3, the lubricating device 50 of the present embodiment reduces the oil pressure of the oil circulating in the oil circulation system 52 from the reference discharge pressure corresponding to the rotational speed of the engine 1. A low hydraulic pressure setting unit 80 as a possible low hydraulic pressure setting means is provided, and the friction work of the oil pump 55 that is driven in conjunction with the crankshaft 10 according to the operating state of the engine 1 is reduced, and toward the bottom surface 2b of the piston 2 By suppressing the injection pressure of the oil jet 60 that injects oil, the fuel consumption is improved and the warm-up property at the cold start is improved.

  The low hydraulic pressure setting unit 80 includes a casing 81, a branch main passage (between the branch mains) 82, a relief passage (relief pipe) 83, a branch sub passage (branch sub pipe) 84, an oil control valve 85, and a discharge. And a passage (discharge pipe) 86.

  The casing 81 is formed in a cylindrical shape, and a first oil chamber 87 and a second oil chamber 88 are formed inside. The first oil chamber 87 is provided on one end side in the axial direction in the casing 81, while the second oil chamber 88 is provided on the other end side. Further, the second oil chamber 88 is formed coaxially with the first oil chamber 87, and the diameter thereof is set larger than the diameter of the first oil chamber 87. Accordingly, the casing 81 is formed with a stepped portion 89 at the boundary between the first oil chamber having a small diameter and the second oil chamber having a large diameter. The first oil chamber 87 is fitted so that the first valve body 90 is movable in the axial direction, while the second oil chamber 88 is fitted so that the second valve body 91 is movable in the axial direction. .

  The first valve body 90 is formed in a cylindrical shape slightly smaller in diameter than the first oil chamber 87, and a pressure receiving surface 90a is provided at one end. The second valve body 91 is formed in a cylindrical shape slightly smaller in diameter than the second oil chamber 88, and a pressure receiving surface 91a is provided at one end. The first valve body 90 and the second valve body 91 are opposite to each other at the casing 81 in the casing 81. The casing 81 is provided with a compression spring 92 as an urging means. The compression spring 92 is provided between the first valve body 90 and the second valve body 91, and both ends thereof are in contact with the back surfaces of the pressure receiving surface 90a and the pressure receiving surface 91a, respectively. Thereby, as will be described later, when the oil is introduced into the first oil chamber 87 and the second oil chamber 88 and the oil pressure acts on the pressure receiving surface 90a and the pressure receiving surface 91a, the compression spring 92 The second valve body 91 can be urged in a direction away from each other.

  The branch main passage 82 is branched from the main passage (main pipe) 52 a forming the oil circulation system 52 by the oil pump 55, and the oil pump 55 and the second passage in the casing 81 are connected through an introduction port 81 a formed in the casing 81. One oil chamber 87 is connected. The inlet 81 a is formed on the end wall surface of the casing 81 so as to face the first oil chamber 87, and is always open to the first oil chamber 87. The branch main passage 82 introduces a part of the oil circulating in the oil circulation system 52 to the first oil chamber 87 through the introduction port 81a.

  The relief passage 83 is connected to the first oil chamber 87 in the casing 81 and the main passage on the upstream side of the oil pump 55 with respect to the direction of oil circulation in the oil circulation system 52 via a discharge port 81 b formed in the casing 81. 52a is connected. The discharge port 81b is formed on the side wall surface of the casing 81 so as to face the first oil chamber 87, and is opened and closed as the first valve body 90 moves along the axial direction. The relief passage 83 circulates oil introduced from the introduction port 81 a into the first oil chamber 87 through the discharge port 81 b that is opened and closed as the first valve body 90 moves, and circulates oil from the first oil chamber 87. The oil is discharged to the upstream side of the oil pump 55 of the system 52.

  The branch sub-passage 84 branches from the branch main passage 82 between the oil pump 55 and the introduction port 81a, and is connected to the oil pump 55 via the introduction / discharge port 81c and the branch main passage 82 formed in the casing 81. The second oil chamber 88 in the casing 81 is connected. The inlet / outlet port 81 c is formed on the side wall surface of the casing 81 so as to face the second oil chamber 88. The branch sub-passage 84 is provided with an oil filter 84a and an oil control valve 85 as a switching unit in the path. In the oil filter 84a and the oil control valve 85, the oil control valve 85 is provided on the introduction / discharge port 81c side, and the oil filter 84a is provided on the oil pump 55 side. That is, in the branching sub-passage 84, an oil control valve 85 is provided between the oil pump 55 and the introduction / discharge port 81c, and an oil filter 84a is further provided between the oil pump 55 and the oil control valve 85.

  The discharge passage 86 branches from the branching sub-passage 84 at one end by the oil control valve 85 and opens into the inner tank 51a of the two-tank oil pan 51 at the other end. The discharge passage 86 discharges the oil introduced into the second oil chamber 88 to the inner tank 51 a of the two-tank oil pan 51 via the introduction discharge port 81 c and the oil control valve 85.

  The oil control valve 85 is constituted by, for example, an electromagnetic valve, and can open and close the branch sub-passage 84 and the discharge passage 86. In other words, the branch sub-passage 84 and the discharge passage 86 can be switched. The oil control valve 85 is electrically connected to the ECU 70, and the driving of the oil control valve 85 is controlled by the ECU 70. Therefore, the oil control valve 85 can switch between the branch sub-passage 84 and the discharge passage 86 according to the operating state of the engine 1 under the control of the ECU 70. Here, when the oil control valve 85 is turned off, the branching sub-passage 84 is opened and the discharge passage 86 is closed to introduce oil into the second oil chamber 88, while when it is turned on, the branching sub-passage 84 is closed. The passage 84 is closed and the discharge passage 86 is opened, and the oil in the second oil chamber 88 is discharged through the discharge passage 86. Therefore, the oil control valve 85 can switch between the introduction of oil into the second oil chamber 88 and the discharge of oil from the second oil chamber 88 via the introduction / discharge port 81c. The oil filter 84a is substantially the same as the oil filter 56 described above, and removes foreign matters in the oil.

  In the normal hydraulic pressure (reference discharge pressure) state, the low hydraulic pressure setting unit 80 configured as described above is in a state where the oil control valve 85 is turned off (the oil in the second oil chamber 88 is turned off) by the ECU 70 as shown in FIG. State in which it is not released to the inner tank 51a). That is, a part of the oil circulating in the oil circulation system 52 is introduced into the first oil chamber 87 through the branch main passage 82 and the inlet 81a, and the branch sub-passage 84 is opened and discharged by the oil control valve 85. Since the passage 86 is closed, it is also introduced into the second oil chamber 88 via the branch sub-passage 84 and the introduction / discharge port 81c.

  Then, the oil pressures of the oil introduced into the first oil chamber 87 and the second oil chamber 88 act on the pressure receiving surface 90a of the first valve body 90 and the pressure receiving surface 91a of the second valve body 91, respectively. Here, the oil pressure acting on the pressure receiving surface 90a and the pressure receiving surface 91a is substantially equal, but the sum of the upward forces in the figure acting on the pressure receiving surface 91a of the second valve body 91 having a large diameter, This is larger than the sum of downward forces acting on the pressure receiving surface 90a of the first valve body 90 having a small diameter. For this reason, the second valve body 91 moves so as to approach the first valve body 90 side while pressing and compressing the compression spring 92. When the second valve body 91 approaches the first valve body 90 side until it abuts on the stepped portion 89, the further movement toward the first valve body 90 side is restricted by the stepped portion 89. Is stopped.

  In this state, the number of rotations of the crankshaft 10 of the engine 1 is increased. Therefore, when the oil discharge pressure by the oil pump 55 is increased, the oil pressure acting on the pressure receiving surface 90a and the pressure receiving surface 91a is also increased. While the movement of the second valve body 91 toward the first valve body 90 is restricted by the stepped portion 89, the force acting on the pressure receiving surface 90a of the first valve body 90 is biased by the compression spring 92 ( Therefore, the first valve body 90 approaches the second valve body 91 side while compressing and compressing the compression spring 92. The first valve body 90 is a force acting in a direction in which the first valve body 90 and the second valve body 91 are separated from each other. To move.

  Then, the rotation speed of the crankshaft 10 becomes higher than a predetermined value, so that the oil discharge pressure by the oil pump 55 becomes higher than the predetermined value, and the pressure receiving surface 90a of the first valve body 90 is connected to the second valve from the discharge port 81b. When moving to the position on the body 91 side, the discharge port 81b is opened to the first oil chamber 87. When the discharge port 81 b is opened with respect to the first oil chamber 87, the first oil chamber 87 and the relief passage 83 communicate with each other, and the oil in the first oil chamber 87 is circulated through the relief passage 83. The oil is discharged to the main passage 52 a upstream of the oil pump 55 of the system 52.

  Accordingly, when the first valve body 90 approaches or separates from the second valve body 91 according to the oil pressure of the oil in the first oil chamber 87, the discharge port 81b is opened and closed, thereby circulating through the oil circulation system 52. When the oil pressure of the oil is excessive, the oil in the first oil chamber 87 is discharged to the upstream side from the oil pump 55 through the relief passage 83, so that the oil pressure is maintained below a predetermined pressure set in advance. be able to. As a result, it is possible to prevent a failure (such as failure of other parts) due to excessive increase in the oil pressure of the oil circulated through the oil circulation system 52. In other words, the low hydraulic pressure setting unit 80 including the relief passage 83, the first oil chamber 87, the first valve body 90, the compression spring 92, and the like discharges excess oil to the upstream side of the oil pump 55, so that the oil pump A so-called relief mechanism that prevents the oil discharge pressure by 55 from rising above a predetermined level is provided.

  On the other hand, in the low oil pressure control state, as shown in FIG. 3, the low oil pressure setting unit 80 has an oil control valve 85 turned on by the ECU 70 (a state in which the oil in the second oil chamber 88 is released to the inner tank 51a). Has been. That is, a part of the oil circulating in the oil circulation system 52 is introduced into the first oil chamber 87 through the branch main passage 82 and the introduction port 81a, while the branch sub passage 84 is closed by the oil control valve 85. Since the discharge passage 86 is open, the introduction of oil into the second oil chamber 88 through the branch sub-passage 84 and the introduction / discharge port 81c is restricted.

  Then, a part of the oil discharged from the oil pump 55 is not introduced into the second oil chamber 88 but is introduced only into the first oil chamber 87, and the pressure receiving surface 90a of the first valve body 90 and the second valve are introduced. It acts only on the pressure receiving surface 90a of the first valve body 90 out of the pressure receiving surface 91a of the body 91. Then, the first valve body 90 in which the discharge pressure due to the oil discharged from the oil pump 55 acts on the pressure receiving surface 90a is pushed to the bottom side (lower side in FIG. 3) of the second oil chamber 88, and the compression spring 92, It moves together with the second valve body 91.

  When the first valve body 90, the compression spring 92, and the second valve body 91 are moved as they are to the bottom side (the lower side in FIG. 3) of the second oil chamber 88, the oil in the second oil chamber 88 becomes the second valve body. It is pushed out from the second oil chamber 88 by 91 and discharged into the inner tank 51 a of the two-tank oil pan 51 through the inlet / outlet port 81 c and the discharge passage 86. At this time, since the first valve body 90, the compression spring 92, and the second valve body 91 are moved to the bottom side (the lower side in FIG. 3) of the second oil chamber 88, the discharge port 81b is always the first oil. Therefore, in the low hydraulic pressure control state, the first oil chamber 87 and the relief passage 83 are always in communication, and the oil introduced into the first oil chamber 87 is The oil is always discharged to the main passage 52 a upstream of the oil pump 55 of the oil circulation system 52 through the relief passage 83.

  Therefore, the low oil pressure setting unit 80 sets the oil control valve 85 to the ON state according to the operating state of the engine 1 and keeps the discharge port 81b open to the first oil chamber 87, so that the oil circulation system 52 is set. A part of the circulating oil is discharged to the upstream side of the oil pump 55, the oil pressure of the oil circulating in the oil circulation system 52 can be reduced, and a low oil pressure control state can be achieved. As a result, the friction work of the oil pump 55 can be reduced in the low hydraulic pressure control state, and the friction work of the oil pump 55 driven in conjunction with the crankshaft 10 can be reduced according to the operating state of the engine 1. Can improve fuel efficiency. Furthermore, for example, the injection pressure of the oil jet 60 that injects oil toward the bottom surface 2b of the piston 2 at the time of cold start can be suppressed. Then, by suppressing the oil injection pressure by the oil jet 60, the temperature of the combustion chamber 5 including the piston 2 is low at the time of cold start, thereby causing poor atomization of fuel spray and poor combustion. By injecting oil onto the bottom surface 2b of the piston 2, it is possible to prevent the piston 2 from being excessively cooled and further promote atomization of fuel spray and deterioration of combustion. Can be improved. Moreover, the discharge amount of unburned hydrocarbon (HC) and particulate matter (PM) can also be suppressed.

  The cold start of the engine 1 may be determined based on, for example, the engine coolant temperature of the engine 1 detected by the water temperature sensor 72. That is, the ECU 70 detects the cold start of the engine 1 when the engine coolant temperature of the engine 1 detected by the water temperature sensor 72 is lower than a preset coolant temperature threshold, and the oil control valve of the low hydraulic pressure setting unit 80 For example, if the cooling water temperature reaches 80 degrees and a complete warm-up state is achieved, low pressure control is performed from 25 degrees to 80 degrees. Good.

  By the way, in the lubricating device 50 of the engine 1 as described above, when the oil pressure of the oil circulating through the oil circulation system 52 is set to the low pressure side by the low oil pressure setting unit 80 as described above, that is, in the low oil pressure control state. In some cases, since the oil pressure is set to the low pressure side, the amount of circulating oil circulating through the oil circulation system 52 is also reduced. In this state, if the amount of oil stored in the inner tank 51 a of the two-tank oil pan 51 is insufficient, the hydraulic pressure is further reduced, and the oil circulation system 52 is connected via the oil strainer 54 by the oil pump 55. There is a risk that the amount of circulating oil may be further reduced by inhaling air. As a result, there is a possibility that image sticking may occur at the sliding portion of the supply target portion 53 of the engine 1. In particular, like the lubricating device 50 of the present embodiment, at the time of cold start, the amount of oil circulating in the oil circulation system 52 is suppressed by circulating mainly the oil stored in the inner tank 51a. In the case where the two-tank oil pan 51 is provided to raise the temperature of the oil at an early stage and improve the warm-up performance, the amount of oil stored in the inner tank 51a tends to be insufficient. There is a risk that it is likely to occur.

  Therefore, as shown in FIGS. 1, 2, and 3, the lubricating device 50 of the engine 1 of the present embodiment includes a level sensor 73 as oil amount detecting means, and an ECU 70 as control means is provided at least in the inner tank 51a. By prohibiting the reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 based on the amount of stored oil, the seizing of the supply target portion 53 of the engine 1 is prevented. Further, the lubrication apparatus 50 of the present embodiment also includes a hydraulic pressure sensor 74 as a hydraulic pressure detection unit, and the ECU 70 prohibits the reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 even based on the hydraulic pressure of the oil circulating in the oil circulation system 52. To do.

  The level sensor 73 detects the amount of oil stored in the two-tank oil pan 51, that is, the amount of oil stored in the inner tank 51a provided with the oil strainer 54 in this embodiment. As the level sensor 73, for example, various level sensors capable of detecting the oil surface position of the oil in the inner tank 51a, such as a buoyancy type level sensor including a float provided in the inner tank 51a and a link mechanism, are used. Can do. The oil pressure sensor 74 detects the oil pressure of the oil circulating in the oil circulation system 52. The oil pressure sensor 74 is provided on the downstream side of the oil pump 55 in the main passage 52 a forming the oil circulation system 52, and various pressure sensors capable of detecting the pressure of oil circulating in the oil circulation system 52 can be used. . The level sensor 73 and the hydraulic pressure sensor 74 are electrically connected to the ECU 70 and transmit the detected oil amount and hydraulic pressure to the ECU 70.

  Then, the ECU 70 controls the oil pressure of the low oil pressure setting unit 80 based on the oil amount in the inner tank 51a detected by the level sensor 73 and the oil pressure of the oil circulating in the oil circulation system 52 detected by the oil pressure sensor 74. The valve 85 is controlled to prohibit the reduction of the hydraulic pressure. The ECU 70 detects when the oil pressure detected by the oil pressure sensor 74 falls below a predetermined pressure when the amount of oil stored in the inner tank 51a detected by the level sensor 73 is less than a predetermined amount, or when the oil pressure sensor 74 detects the oil pressure. When the amount of oil stored in the inner tank 51a detected by the level sensor 73 when the oil pressure of the oil circulating in the oil circulation system 52 is lower than a predetermined pressure, the oil pressure by the low oil pressure setting unit 80 is reduced. The reduction of For example, when the temperature of the oil is low, the oil viscosity is high. For this reason, the oil once supplied from the two-tank type oil pan 51 to the supply target portion 53 has a reduced fluidity. Return to the two-tank oil pan 51 becomes worse, and the amount of oil returned to the two-tank oil pan 51 decreases. And if there is little return oil amount to the two-tank type oil pan 51 and there is little storage oil amount, there exists a possibility that air may be inhaled, and if the low oil pressure control state is executed in this state, the inner tank 51a. Since the amount of stored oil is insufficient and the hydraulic pressure also decreases, there is a possibility that the supply target portion 53 of the engine 1 will be seized. In the low oil pressure control state, the amount of oil circulating through the oil circulation system 52 is decreased by lowering the oil pressure. In this state, when the operating state of the engine 1 shifts to the high rotation state, the engine 1 There is a possibility that the amount of oil supplied to the sliding portion of the supply target portion 53 is insufficient, and the amount of circulating oil is insufficient to cause seizing. Therefore, low oil pressure control is prohibited.

  Specifically, the ECU 70 detects when the oil amount in the inner tank 51a detected by the level sensor 73 is equal to or less than a preset oil amount threshold value, or in the oil circulation system 52 detected by the hydraulic sensor 74. When the oil pressure of the circulating oil is equal to or lower than a preset oil pressure threshold value, for example, the oil control valve 85 is turned off even if the low oil pressure control is executed at the cold start of the engine 1 as described above. In this state, the reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 is prohibited.

  Here, the oil amount threshold is set according to the number of revolutions of the engine 1. FIG. 4 is a diagram showing the relationship between the engine speed and the oil amount threshold, where the horizontal axis represents the engine speed and the vertical axis represents the oil amount threshold. That is, the higher the number of revolutions of the engine 1, the greater the amount of oil necessary to prevent seizure at the sliding portion of the supply target portion 53 of the engine 1, so that the oil circulation system 52 is circulated. A large amount of circulating oil is also required. That is, a large amount of oil stored in the inner tank 51a is required. In other words, if the amount of oil stored in the inner tank 51a is large, low oil pressure control can be executed even if the engine 1 has a relatively high rotational speed. If the number is higher than the predetermined number of revolutions, the amount of stored oil may be insufficient, and as a result, the amount of circulating oil may be insufficient. Therefore, it is necessary to prohibit low oil pressure control. That is, the oil amount threshold is set as a large value as the engine speed of the engine 1 increases, and is set as a small value as the engine speed of the engine 1 decreases. The ECU 70 sets an oil amount threshold value based on the number of revolutions of the engine 1 detected by the crank angle sensor 71, and is low when the oil amount of the oil in the inner tank 51a detected by the level sensor 73 is below this oil amount threshold value. Reduction of oil pressure by the oil pressure setting unit 80 is prohibited.

  Further, the hydraulic pressure threshold is also set according to the rotational speed of the engine 1. FIG. 5 is a diagram showing the relationship between the engine speed and the hydraulic pressure threshold, where the horizontal axis is the engine speed and the vertical axis is the hydraulic threshold. Even if the amount of oil in the inner tank 51a is a sufficient amount of stored oil, if the oil pressure is low, the amount of oil circulating in the oil circulation system 52 will decrease, so the amount of oil circulating in the oil circulation system 52 will decrease. The hydraulic pressure needs to be such that the amount of circulating oil necessary for preventing seizure at the sliding portion of the supply target portion 53 according to the rotational speed of the engine 1 can be pumped. Therefore, the hydraulic pressure threshold is also set to a larger value as the engine speed of the engine 1 increases, and is set to a smaller value as the engine speed of the engine 1 decreases. The ECU 70 sets a hydraulic pressure threshold based on the rotation speed of the engine 1 detected by the crank angle sensor 71, and the hydraulic pressure of the oil circulating in the oil circulation system 52 detected by the hydraulic sensor 74 is lower than the hydraulic pressure threshold. Even in this case, reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 is prohibited. The ECU 70 according to the present embodiment uses the oil circulating in the oil circulation system 52 detected by the oil pressure sensor 74 when the oil amount of the oil in the inner tank 51a detected by the level sensor 73 is equal to or less than a preset oil amount threshold. In any case where the hydraulic pressure is equal to or lower than a preset hydraulic pressure threshold, the reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 is prohibited. As a result, the ECU 70 prohibits the reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 based on the oil amount and the hydraulic pressure, thereby preventing the sliding portion of the supply target portion 53 from seizing in accordance with the operating state of the engine 1. Therefore, it is possible to reliably supply the necessary amount of oil, so that it is possible to prevent the supply target portion 53 of the engine 1 from being seized.

  Since the oil pressure threshold tends to have temperature dependence, an oil temperature sensor is provided in the oil circulation system 52 and is set based on the oil temperature of the oil detected by the oil temperature sensor and the rotation speed of the engine 1. You may make it do. In this case, it is possible to more reliably prevent the supply target portion 53 from being seized. Further, the ECU 70 calculates a determination value from the oil amount of the oil in the inner tank 51a detected by the level sensor 73 and the oil pressure of the oil circulating in the oil circulation system 52 detected by the oil pressure sensor 74, and the oil temperature of the oil Alternatively, a threshold value based on the rotation speed of the engine 1 may be set for the determination value, the threshold value and the determination value may be compared, and the reduction of the hydraulic pressure may be prohibited based on the comparison result.

  According to the lubrication apparatus 50 for the engine 1 according to the embodiment of the present invention described above, the oil to be supplied to the engine 1 by pressurizing the oil stored in the two-tank oil pan 51 to the reference discharge pressure by the oil pump 55. 53 and the oil circulation system 52 that can be recovered in the two-tank oil pan 51 and the oil pressure of the oil circulating through the oil circulation system 52 according to the operating state of the engine 1 according to the rotational speed of the engine 1. A low oil pressure setting unit 80 that can be reduced below the reference discharge pressure, a level sensor 73 that detects the amount of oil stored in the two-tank oil pan 51, and at least the amount of oil detected by the level sensor 73 are preset. The ECU 70 includes an ECU 70 that can control the low oil pressure setting unit 80 and prohibit the reduction of the oil pressure when the oil amount is equal to or less than the oil amount threshold.

  Therefore, the level sensor 73 detects the amount of oil stored in the two-tank oil pan 51, and the oil amount is determined based on at least the detected oil amount and a preset oil amount threshold. In the following cases, for example, when the amount of oil stored in the inner tank 51a is insufficient and air is easily sucked into the oil circulation system 52, the ECU 70 prohibits the oil pressure reduction by the low oil pressure setting unit 80 from the ECU 70. Since the required amount of oil can be reliably supplied to the sliding portion of the supply target portion 53 according to the operating state of the engine 1, seizure of the supply target portion 53 of the engine 1 can be prevented.

  Furthermore, according to the lubricating device 50 of the engine 1 according to the embodiment of the present invention described above, the hydraulic sensor 74 for detecting the oil pressure of the oil circulating in the oil circulation system 52 is provided, and the ECU 70 detects the oil pressure sensor 74. When the hydraulic pressure is less than or equal to a preset hydraulic pressure threshold, the reduction of the hydraulic pressure is prohibited. Accordingly, when the oil pressure circulating through the oil circulation system 52 is detected by the oil pressure sensor 74 and the oil pressure is equal to or lower than the oil pressure threshold based on the detected oil pressure and a preset oil pressure threshold, for example, the oil circulation In a state where there is a high possibility that seizure will occur in the supply target portion 53, such as when the oil pressure circulating through the system 52 is insufficient and the amount of oil supplied to the sliding portion of the supply target portion 53 is likely to be insufficient. Since the ECU 70 prohibits the oil pressure from being reduced by the low oil pressure setting unit 80, the required amount of oil can be reliably supplied to the sliding portion of the supply target portion 53 in accordance with the operating state of the engine 1. In addition, it is possible to reliably prevent the supply target portion 53 of the engine 1 from being seized.

  Furthermore, according to the lubrication apparatus 50 for the engine 1 according to the embodiment of the present invention described above, the crank angle sensor 71 that detects the rotational speed of the engine 1 is provided, and the ECU 70 performs oil oil based on the rotational speed of the engine 1. Set volume threshold and oil pressure threshold. Therefore, it is possible to set an appropriate oil amount threshold value and hydraulic pressure threshold value according to the rotational speed of the engine 1. For this reason, the reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 can be executed in as long a period as possible according to the rotational speed of the engine 1 other than during cold start, for example.

  Furthermore, according to the lubricating device 50 of the engine 1 according to the embodiment of the present invention described above, the two-tank oil pan 51 includes an inner tank 51a provided with an oil strainer 54 that sucks oil into the oil circulation system 52; The inner tank 51a has an outer tank 51b that is partitioned and partially communicated, and the level sensor 73 detects the amount of oil stored in the inner tank 51a. Therefore, for example, at the time of cold start where the temperature of the oil is low and the viscosity is high, the oil stored in the inner tank 51a provided with the oil strainer 54 is mainly sucked into the oil circulation system 52 and circulated easily. As a result, the total amount of oil circulating through the oil circulation system 52 is relatively reduced. Since the total amount of oil circulating in the oil circulation system 52 is relatively small, the temperature of the oil is easily raised early, and as a result, the warm-up property of the engine 1 can be improved.

  And the capacity | capacitance of one storage part becomes small by partitioning into two tanks of the inner tank 51a and the outer tank 51b in this way, Therefore, the oil amount of the oil stored in the inner tank 51a is insufficient. In this lubricating device 50 including the two-tank type oil pan 51 that easily causes the seizure of the portion 53 to be supplied, the ECU 70 prohibits the reduction of the hydraulic pressure by the low hydraulic pressure setting unit 80 as described above. In addition, it is possible to exert the effect of preventing the supply target portion 53 from being seized.

  Furthermore, according to the lubricating device 50 of the engine 1 according to the embodiment of the present invention described above, the supply target portion 53 includes the oil jet 60 that can inject oil toward the piston 2 of the engine 1. Therefore, by reducing the oil pressure of the oil circulating through the oil circulation system 52 according to the operating state of the engine 1 by the low oil pressure setting unit 80, for example, the oil is directed toward the bottom surface 2b of the piston 2 when the engine 1 is cold started. Since the injection pressure of the oil jet 60 that injects the oil can be suppressed, the warm-up performance of the engine 1 to which the lubricating device 50 is applied can be improved.

  Furthermore, according to the lubricating device 50 for the engine 1 according to the embodiment of the present invention described above, the oil pump 55 can be driven in conjunction with the engine 1 to pressurize the oil. Therefore, by reducing the oil pressure of the oil circulating through the oil circulation system 52 according to the operating state of the engine 1 by the low oil pressure setting unit 80, the friction work of the oil pump 55 driven in conjunction with the crankshaft 10 is reduced. Therefore, the fuel consumption of the engine 1 to which the lubricating device 50 is applied can be improved.

  Furthermore, according to the lubricating device 50 of the engine 1 according to the embodiment of the present invention described above, the low hydraulic pressure setting unit 80 includes the introduction port 81a into which a part of the oil circulating in the oil circulation system 52 is introduced and the oil A first oil chamber 87 having a discharge port 81b through which oil can be discharged upstream of the oil pump 55 with respect to the direction of oil circulation in the circulation system 52, and discharge according to the oil pressure in the first oil chamber 87. A first valve body 90 capable of opening and closing the outlet 81b; a second oil chamber 88 having an inlet / outlet port 81c through which a part of oil circulating in the oil circulation system 52 can be introduced and discharged; and a second oil chamber The second valve body 91 capable of restricting the opening and closing of the discharge port 81b by the first valve body 90 according to the oil pressure in the oil 88, and the introduction of the oil into the second oil chamber 88 through the introduction / discharge port 81c and the second 2 Switching between oil discharge from oil chamber 88 Possible and an oil control valve 85.

  Accordingly, oil is introduced into the second oil chamber 88, and the second valve body 91 regulates the opening and closing of the discharge port 81b by the first valve body 90 in accordance with the oil pressure of the oil in the second oil chamber 88. Since the first valve body 90 opens and closes the discharge port 81b according to the oil pressure in the first oil chamber 87, when the oil pressure of the oil circulated through the oil circulation system 52 becomes excessive, the first oil By discharging the oil in the chamber 87 to the upstream side of the oil pump 55, the hydraulic pressure can be maintained below a predetermined pressure set in advance. As a result, it is possible to prevent a failure (such as failure of other parts) due to excessive increase in the oil pressure of the oil circulated through the oil circulation system 52. Then, by switching the oil control valve 85 and discharging the oil in the second oil chamber 88, the first valve body 90, the compression spring 92, and the second valve body 91 are on the bottom side of the second oil chamber 88 (FIG. 3). Therefore, the discharge port 81b is always open to the first oil chamber 87, and the oil introduced into the first oil chamber 87 is always discharged upstream from the oil pump 55. Therefore, the oil pressure of the oil circulating through the oil circulation system 52 can be reduced by the low oil pressure setting unit 80, and a low oil pressure control state can be established. As a result, a so-called relief mechanism and a mechanism for setting the oil circulating through the oil circulation system 52 to a low oil pressure can be realized by the low oil pressure setting unit 80, and the lubricating device 50 having a more compact configuration can be obtained. Can do.

  FIG. 8 is a schematic cross-sectional view of an internal combustion engine lubrication device according to Embodiment 2 of the present invention. The lubrication device for an internal combustion engine according to the second embodiment has substantially the same configuration as the lubrication device for the internal combustion engine according to the first embodiment, but is different from the lubrication device for the internal combustion engine according to the first embodiment in that an inclination detection unit is provided. Different. In addition, about the structure, effect | action, and effect which are common in the Example mentioned above, while overlapping description is abbreviate | omitted as much as possible, the same code | symbol is attached | subjected.

  As shown in FIG. 8, the lubricating device 250 of the engine 1 as the internal combustion engine according to the second embodiment further detects an inclination of the oil level of the oil stored in the inner tank 51 a of the two-tank oil pan 51. A G sensor 275 is provided as detection means. As the G sensor 275, various G sensors capable of measuring acceleration acting on a vehicle on which the engine 1 is mounted can be used. The G sensor 275 is electrically connected to the ECU 70 and transmits the detected acceleration to the ECU 70.

  Here, the oil level of the oil stored in the inner tank 51a varies according to the acceleration detected by the G sensor 275. That is, for example, when a vehicle on which the engine 1 is mounted suddenly starts, turns sharply, climbs or descends, the acceleration (gravity) also acts on the oil stored in the inner tank 51a, and the inner tank 51a The stored oil may be biased in the inner tank 51a due to an inertial force corresponding to the acceleration, for example, as indicated by a one-dot chain line in FIG. Then, the oil level position of the oil stored in the inner tank 51a has an inclination with respect to the oil level position in a stationary state. In other words, the acceleration detected by the G sensor 275 can be regarded as a value corresponding to the inclination of the oil level of the oil stored in the inner tank 51a with respect to the horizontal direction.

  When the oil level of the oil stored in the inner tank 51a is inclined as shown by a one-dot chain line in FIG. 8, that is, when the oil level is inclined counterclockwise in the figure (two-tank oil pan When the oil 51 is inclined in the clockwise direction in the drawing), the distance from the oil strainer 54 to the oil surface position of the oil becomes long, and thereby the oil that can be sucked into the oil circulation system 52 from the oil strainer 54 The amount may decrease. As a result, inhalation of air may occur as in the case where the amount of oil stored in the inner tank 51a described in the first embodiment is reduced. The same applies when the engine 1 itself has an inclination.

  Therefore, when the acceleration detected by the G sensor 275 is greater than a preset threshold, the ECU 70 of the lubricating device 250 of the present embodiment, in other words, the oil level position of the oil stored in the inner tank 51a. When the inclination with respect to the stationary position becomes larger than a preset threshold value, the low oil pressure setting unit 80 is controlled to turn the oil control valve 85 to the ON state and prohibit the reduction of the oil pressure. As a result, the amount of oil necessary to prevent the sliding portion of the supply target portion 53 from being seized can be reliably supplied, so that the supply target portion 53 of the engine 1 can be prevented from being seized.

  Note that the threshold value set in advance for the acceleration detected by the G sensor 275 may be set in advance according to the size of the inner tank 51a and the mounting position of the oil strainer 54. Here, the inclination detecting means for detecting the inclination of the oil level of the oil stored in the inner tank 51a of the two-tank oil pan 51 is described as the G sensor 275. However, the inclination of the oil level of the oil is described. Any sensor can be used as long as the sensor can detect a value corresponding to the inclination of the oil level of the oil, or a steering angle sensor of a vehicle on which the engine 1 is mounted or within a predetermined time. A means for detecting acceleration information based on the speed difference in the above, a brake (braking) sensor, or the like may be used.

  According to the lubricating device 250 of the engine 1 according to the embodiment of the present invention described above, the oil amount stored in the two-tank oil pan 51 is detected by the level sensor 73, and the oil amount detected by the ECU 70 is detected. When the oil amount is equal to or less than the oil amount threshold value, the ECU 70 prohibits the oil pressure from being reduced by the low oil pressure setting unit 80, and therefore, according to the operating state of the engine 1. As a result, the required amount of oil can be reliably supplied to the sliding portion of the supply target portion 53, so that the supply target portion 53 of the engine 1 can be prevented from being seized.

  Furthermore, according to the lubricating device 250 of the engine 1 according to the embodiment of the present invention described above, a value corresponding to the inclination of the oil level of the oil stored in the inner tank 51a of the two-tank oil pan 51 is detected. The G sensor 275 is provided, and the ECU 70 can inhibit the oil pressure reduction by controlling the low oil pressure setting unit 80 based on a value corresponding to the oil inclination detected by the G sensor 275. Accordingly, since the ECU 70 controls the low oil pressure setting unit 80 according to the inclination of the oil level of the oil stored in the inner tank 51a and prohibits the reduction of the oil pressure, for example, the oil of the oil stored in the inner tank 51a. Even when the surface position is inclined relative to the inner tank 51a and the amount of oil that can be sucked into the oil circulation system 52 from the oil strainer 54 is substantially reduced, the supply target portion 53 of the engine 1 is reduced. Burn-in can be reliably prevented.

  FIG. 9 is a schematic cross-sectional view of an internal combustion engine lubrication device according to Embodiment 3 of the present invention. The internal combustion engine lubrication device according to the third embodiment has substantially the same configuration as that of the internal combustion engine lubrication device according to the first embodiment, but includes the communication unit controlled by the control unit. This is different from the lubrication system. In addition, about the structure, effect | action, and effect which are common in the Example mentioned above, while overlapping description is abbreviate | omitted as much as possible, the same code | symbol is attached | subjected.

  As shown in FIG. 9, the lubrication device 350 of the engine 1 as the internal combustion engine according to the third embodiment is a communication unit capable of communicating the inner tank 51 a and the outer tank 51 b in the oil stored in the outer tank 51 b. A communication unit 393 is provided. The communication portion 393 includes a communication hole 393a provided on the bottom surface of the inner tank 51a, and a control valve 393b as an opening / closing means that can open and close the communication hole 393a.

  The control valve 393b is provided in the communication hole 393a. The control valve 393b is constituted by, for example, an electromagnetic valve, and can open and close the communication hole 393a. The control valve 393b is electrically connected to the ECU 70, and the driving of the control valve 393b is controlled by the ECU 70. Therefore, the control valve 393 b can open and close the communication hole 393 a according to the operating state of the engine 1 under the control of the ECU 70. Then, when the ECU 70 controls the low hydraulic pressure setting unit 80 to prohibit the reduction of the hydraulic pressure, the ECU 70 controls the control valve 393b of the communication unit 393 to open the communication hole 393a, thereby connecting the inner tank 51a and the outer tank 51b. Communicate. Thereby, when the amount of oil stored in the inner tank 51a is small, the oil can be replenished from the outer tank 51b to the inner tank 51a through the open communication hole 393a. The oil amount and the hydraulic pressure can be ensured, and seizure of the supply target portion 53 of the engine 1 can be reliably prevented. In the present embodiment, since the communication portion 393 is provided, the communication hole 51c described in the first embodiment may not be provided.

  According to the lubricating device 350 of the engine 1 according to the embodiment of the present invention described above, the oil amount stored in the two-tank oil pan 51 is detected by the level sensor 73, and at least the detected oil amount and When the oil amount is equal to or less than the oil amount threshold value based on the preset oil amount threshold value, the ECU 70 prohibits the oil pressure from being reduced by the low oil pressure setting unit 80. Since the necessary amount of oil can be reliably supplied to the sliding portion of the supply target portion 53, seizure of the supply target portion 53 of the engine 1 can be prevented.

  Furthermore, according to the lubricating device 350 of the engine 1 according to the embodiment of the present invention described above, the communication portion 393 capable of communicating the inner tank 51a and the outer tank 51b in the oil stored in the outer tank 51b is provided. When the ECU 70 controls the low oil pressure setting unit 80 to prohibit the reduction of the oil pressure, the ECU 70 controls the communication unit 393 to connect the inner tank 51a and the outer tank 51b. Therefore, when the amount of oil stored in the inner tank 51a is small, the oil can be replenished from the outer tank 51b to the inner tank 51a through the open communication hole 393a. The amount and the hydraulic pressure can be ensured, and the supply target portion 53 of the engine 1 can be reliably prevented from being seized. As a result, it is possible to ensure a long period during which the oil pressure can be reduced by the low oil pressure setting unit 80.

  The lubricating device for an internal combustion engine according to the above-described embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims. In the above description, the engine 1 to which the lubricating device is applied has been described as a direct injection engine, but may be applied to a port injection type engine.

  In the above description, the two-tank oil pan 51 as the storage means has been described as having the inner tank 51a as the first storage section and the outer tank 51b as the second storage section. Not only a single tank oil pan, but also an effect of preventing seizure of the internal combustion engine by the internal combustion engine lubrication device of the present invention can be achieved. Moreover, you may make it comprise a 2 tank type oil pan by the positional relationship that a 1st storage part and a 2nd storage part are not adjacent to an internal / external positional relationship but adjacent. Further, the pressurizing means may be an electric oil pump. Even in this case, since the low oil pressure setting means reduces the oil pressure of the lubricating oil circulating in the lubricating oil circulation system, the electric load on the engine can be suppressed, and as a result, the fuel consumption can be improved.

  As described above, the lubricating device for an internal combustion engine according to the present invention prevents seizure of the internal combustion engine, and is particularly suitable for application to an internal combustion engine having a small lubricating oil storage capacity.

1 is a schematic cross-sectional view of a lubricating device for an internal combustion engine according to Embodiment 1 of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of an internal combustion engine lubrication device according to Embodiment 1 of the present invention during oil relief. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view during low oil pressure control of a lubricating device for an internal combustion engine according to Embodiment 1 of the present invention. It is a diagram which shows the relationship between the engine speed in the lubricating device of the internal combustion engine which concerns on Example 1 of this invention, and an oil quantity threshold value. It is a diagram which shows the relationship between the engine speed in the lubricating device of the internal combustion engine which concerns on Example 1 of this invention, and a hydraulic pressure threshold value. 1 is a schematic cross-sectional view of an engine to which a lubricating device for an internal combustion engine according to a first embodiment of the present invention is applied. 1 is a schematic configuration diagram illustrating a lubricating oil circulation system of a lubricating device for an internal combustion engine according to a first embodiment of the present invention. It is typical sectional drawing of the lubricating device of the internal combustion engine which concerns on Example 2 of this invention. It is typical sectional drawing of the lubricating device of the internal combustion engine which concerns on Example 3 of this invention.

Explanation of symbols

1 engine (internal combustion engine)
2 Piston 5 Combustion chamber 10 Crankshaft 50, 250, 350 Lubricator 51 Two-tank oil pan (storage means)
51a Inner tank (first reservoir)
51b Outer tank (second reservoir)
52 Oil circulation system (lubricating oil circulation system)
53 Supply object 54 Oil strainer (suction part)
55 Oil pump (pressurizing means)
60 Oil jet (injection means)
70 ECU (control means)
71 Crank angle sensor (rotational speed detection means)
73 Level sensor (oil quantity detection means)
74 Oil pressure sensor (oil pressure detection means)
80 Low oil pressure setting section (low oil pressure setting means)
81 Casing 81a Inlet 81b Outlet 81c Inlet / outlet 82 Branch main passage 83 Relief passage 84 Branch subpassage 85 Oil control valve (switching portion)
86 Discharge passage 87 First oil chamber 88 Second oil chamber 89 Stepped portion 90 First valve body 90a, 91a Pressure receiving surface 91 Second valve body 92 Compression spring 275 G sensor (tilt detection means)
393 communication part (communication means)
393a Communication hole 393b Control valve

Claims (9)

A lubricating oil circulation system that is pressurized to a reference discharge pressure by a pressurizing means and supplied to a supply target part of an internal combustion engine by the pressurizing means, and can be collected in the storing means;
Low oil pressure setting means capable of reducing the oil pressure of the lubricating oil circulating in the lubricating oil circulation system from the reference discharge pressure according to the rotational speed of the internal combustion engine according to the operating state of the internal combustion engine;
An oil amount detecting means for detecting an oil amount of the lubricating oil stored in the storing means;
And a control unit capable of controlling the low hydraulic pressure setting unit and prohibiting the reduction of the hydraulic pressure when the oil amount detected by the oil amount detection unit is equal to or less than a preset oil amount threshold value. And
Lubricating device for internal combustion engine. A hydraulic pressure detecting means for detecting a hydraulic pressure of the lubricating oil circulating in the lubricating oil circulation system;
The control means prohibits the reduction of the oil pressure when the oil pressure detected by the oil pressure detecting means is less than or equal to a preset oil pressure threshold value.
The lubricating device for an internal combustion engine according to claim 1. A rotation speed detecting means for detecting the rotation speed of the internal combustion engine;
The control means sets the oil amount threshold value and the hydraulic pressure threshold value based on the rotation speed of the internal combustion engine,
The internal combustion engine lubrication device according to claim 2. The storage means has a first storage part provided with a suction part for sucking the lubricating oil into the lubricating oil circulation system, and a second storage part that is partitioned from the first storage part and partially communicated therewith. And
The oil amount detection means detects the amount of the lubricating oil stored in the first storage unit,
The internal combustion engine lubricating device according to any one of claims 1 to 3. Comprising communication means capable of communicating the first reservoir and the second reservoir in the lubricating oil stored in the second reservoir;
The control means controls the communication means to connect the first storage section and the second storage section when the low hydraulic pressure setting means is controlled to prohibit the reduction of the hydraulic pressure. To
The internal combustion engine lubrication device according to claim 4. Inclination detection means for detecting the inclination of the oil surface of the lubricating oil stored in the storage means,
The control means can control the low oil pressure setting means based on the inclination of the lubricating oil detected by the inclination detection means and prohibit the reduction of the oil pressure.
The internal combustion engine lubricating device according to any one of claims 1 to 5. The supply target portion includes injection means capable of injecting the lubricating oil toward a piston of the internal combustion engine.
The internal combustion engine lubricating device according to any one of claims 1 to 6. The pressurizing means is driven in conjunction with the internal combustion engine to pressurize the lubricating oil,
The internal combustion engine lubricating device according to any one of claims 1 to 7. The low hydraulic pressure setting means is upstream of the pressurizing means with respect to an inlet for introducing a part of the lubricating oil that circulates through the lubricating oil circulation system and a circulating direction of the lubricating oil in the lubricating oil circulation system. A first oil chamber having a discharge port through which the lubricating oil can be discharged, a first valve body capable of opening and closing the discharge port in accordance with a hydraulic pressure of the lubricating oil in the first oil chamber, and the lubricating oil circulation A second oil chamber having an introduction / exhaust port through which a part of the lubricating oil circulating in the system can be introduced and discharged, and the first valve body according to a hydraulic pressure of the lubricating oil in the second oil chamber Switching between the second valve body capable of restricting the opening and closing of the discharge port, the introduction of the lubricating oil into the second oil chamber via the introduction discharge port, and the discharge of the lubricating oil from the second oil chamber A switching unit capable of
The internal combustion engine lubricating device according to any one of claims 1 to 8.

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