JP5835004B2 - Abnormality determination device for internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine abnormality determination device, and more particularly, to an internal combustion engine abnormality determination device that determines an oil pressure abnormality caused by a decrease in oil level.

2. Description of the Related Art Conventionally, there is known an oil supply device for an internal combustion engine that discharges oil stored in an oil pan from an oil pump and supplies the oil to a supply site.
Normally, the supplied parts of the internal combustion engine include hydraulic drive parts mounted on the internal combustion engine such as a hydraulic variable valve mechanism and a hydraulic lash adjuster of the valve system, and sliding parts such as a crankshaft and a camshaft. It consists of

  Conventionally, in an internal combustion engine mounted on a vehicle, as an oil supply device that supplies oil used for lubrication and cooling of the internal combustion engine to a supply site of the internal combustion engine, an oil discharge amount proportional to the rotation speed of the internal combustion engine is set. An oil pump is used.

By the way, the oil stored in the oil pan is supplied to the supply site by the oil pump and then collected in the oil pan.
At this time, if the amount of oil stored in the oil pan is small, the recovery efficiency of the oil recovered in the oil pan deteriorates, and the oil level (oil level) stored in the oil pan is less than the appropriate amount. Decline, that is, lack.

  When the oil level decreases in this way, the strainer for sucking oil from the oil pan toward the oil pump may be in a state of sucking air (hereinafter, this state is referred to as air sucking).

When the oil pump is in the air sucking state, the oil discharge pressure discharged from the oil pump will drop, so it will not be possible to supply oil from the oil pump to the supply site with sufficient oil discharge amount and oil discharge pressure. For example, there is a possibility that the lubricity of the sliding part may be deteriorated or abnormal behavior of the hydraulically driven parts may occur.
For this reason, it is necessary to detect an abnormality in the oil discharge pressure and detect that the oil level stored in the oil pan has decreased.

  Conventionally, an oil discharge pressure abnormality is detected by detecting the oil pump discharge pressure with a hydraulic sensor, and when the value detected by the hydraulic sensor is below the pressure drop judgment value, air is sucked into the oil pump. There is known a hydraulic control device for an internal combustion engine in which it is determined that the discharge pressure of an oil pump has decreased due to this (see, for example, Patent Document 1).

JP 2010-242527 A

  However, in the conventional hydraulic control device for an internal combustion engine, when the value detected by the hydraulic sensor is lower than the pressure drop determination value, it is determined that the discharge pressure of the oil pump has decreased. It cannot be reliably detected that the oil discharge pressure has decreased due to an increase in the bubble ratio.

  That is, in the trochoid pump and gear pump that are frequently used as oil pumps, the centers of the inner rotor and the outer rotor are eccentric from each other, and the number of teeth of the inner rotor is one less than the number of teeth of the outer rotor. The pumping action is performed by expanding and contracting.

Since the space between one rotor faces the discharge port in a compressed state, high-pressure oil is discharged during discharge. When the next space between the rotors faces the discharge port, the high pressure oil is discharged again. Then, the pressure is low between the discharge of the high pressure oil and the next discharge of the high pressure oil.
Therefore, oil pressure fluctuations, that is, pressure pulsations are generated by alternately repeating high and low pressures as the rotor rotates.

  Also, when the oil pump is in the air sucking state, the oil pump bites the bubbles, so-called air biting, and pressure pulsation different from the pressure pulsation when the oil level is normal occurs, and the bubbles contained in the oil As the rate increases, the pressure pulsation changes with the bubble rate.

  Since this pressure pulsation has a pressure fluctuation range, it is difficult to detect a drop in the oil discharge pressure by setting a constant pressure drop judgment value for the pressure fluctuation range as in the prior art. In view of the bubble rate, it cannot be reliably detected that the discharge pressure of the oil pump has decreased.

  Therefore, it is impossible to detect at an early stage that the oil level stored in the oil pan has been lowered, and there is a possibility that the sliding portion may be burned or the behavior of the hydraulically driven parts is deteriorated.

  For example, the behavior of a hydraulic variable valve mechanism that constitutes a hydraulic drive component may become unstable when the ratio of bubbles mixed into the oil is high even when the oil pressure is high. Therefore, it is necessary to detect at an early stage that the rate of bubbles mixed into the oil has increased.

  The present invention was made to solve the above-described conventional problems, and the oil level was lowered by estimating that the bubble rate increased from the magnitude of the pressure pulsation of the discharge pressure of the oil pump. An object of the present invention is to provide an abnormality determination device for an internal combustion engine that can detect the engine at an early stage.

In order to achieve the above object, an abnormality determination device for an internal combustion engine according to the present invention is (1) an abnormality determination device for an internal combustion engine having an oil pump that supplies oil stored in an oil storage means to a supply site. , A hydraulic pressure detection means for detecting the pressure of oil discharged from the oil pump, and a threshold value in which a fluctuation range of pressure pulsation of the oil discharged from the oil pump is determined based on detection information of the hydraulic pressure detection means The supplied portion having an abnormality determining means for determining an oil pressure abnormality is connected to a camshaft inside a first rotating body connected to an output shaft of the internal combustion engine. The second rotating body is rotatably accommodated, and the hydraulic pressure in the advance side hydraulic chamber and the retarded side hydraulic chamber partitioned by the first rotating body and the second rotating body is selectively supplied. By And a variable valve timing mechanism that varies a relative rotational phase between the camshaft and the output shaft, wherein the abnormality determining means has a fluctuation range of pressure pulsation of oil discharged from the oil pump being less than a predetermined threshold value. On the condition that the second rotating body is rotated with respect to the first rotating body, the holding control is performed, and the holding control is performed on the advance side hydraulic chamber with the oil And the second rotating body is locked to the first rotating body by discharging the oil from the retard side hydraulic chamber .

  This abnormality determination device for an internal combustion engine has abnormality determination means for determining an oil pressure abnormality on the condition that the fluctuation range of the pressure pulsation of the oil discharged from the oil pump is less than a predetermined threshold value. Based on the magnitude of the pressure pulsation, it can be estimated that the ratio of bubbles mixed in the oil has increased.

  That is, when the oil level of the oil storage means is appropriate and the discharge pressure of the oil pump is normal, the oil pressure pulsation increases. Also, as the oil level increases as the oil level decreases, the vibration generated when the oil pump bites the air bubbles becomes a pressure pulsation, and this pressure pulsation reduces the amount of oil sucked into the oil pump. Since the bubbles are caught in the state, the fluctuation range is smaller than the pressure pulsation when the oil level is normal.

  Therefore, by detecting the fluctuation range of the pressure pulsation by the hydraulic pressure detection means, the abnormality determination means can estimate that the bubble rate of oil has increased, and that the oil level of the oil storage means has decreased early. Can be detected. As a result, the supply site can be protected early.

  (1) In the internal combustion engine abnormality determination device according to (1), (2) warning means for giving a warning based on an abnormality signal output from the abnormality determination means is provided, and the abnormality determination means is discharged from the oil pump. On the condition that the fluctuation range of the oil pressure pulsation is less than a predetermined threshold, the abnormality signal is output to the warning means.

  In this internal combustion engine abnormality determination device, the abnormality determination means outputs an abnormality signal to the warning means on the condition that the fluctuation range of the pressure pulsation of the oil discharged from the oil pump is less than a predetermined threshold value. The driver can be warned that the oil level stored in the oil storage means has decreased. For this reason, it is possible to prompt the driver to check the oil in the oil storage means or to replenish the oil storage means with oil.

  (1) In the internal combustion engine abnormality determination device according to (1) or (2), (3) the abnormality determination means has a fluctuation range of pressure pulsation of oil discharged from the oil pump being less than a predetermined threshold value. On the condition that the rotational speed of the internal combustion engine is controlled so as not to exceed a predetermined rotational speed.

  This abnormality determination device for an internal combustion engine is configured so that when the abnormality determination means reduces the oil level stored in the oil storage means during high rotation of the internal combustion engine and the amount of oil supplied to the supply site is small, By reducing the number of revolutions, it is possible to protect the internal combustion engine by preventing the supply site from being burned.

  According to the present invention, an abnormality determination device for an internal combustion engine capable of detecting at an early stage that the oil level has decreased by estimating that the bubble rate has increased from the magnitude of the pressure pulsation of the discharge pressure of the oil pump. Can be provided.

1 is a diagram showing an embodiment of an abnormality determination device for an internal combustion engine according to the present invention, and is a schematic configuration of a vehicle including an abnormality determination device for an internal combustion engine. 1 is a diagram showing an embodiment of an abnormality determination device for an internal combustion engine according to the present invention, and is a schematic configuration diagram of the engine. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an embodiment of an abnormality determination device for an internal combustion engine according to the present invention, and is a block diagram showing each supplied portion of the engine and the flow of oil. It is a figure which shows one Embodiment of the abnormality determination apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the schematic structure of VVT, and the supply route of the oil which supplies oil to VVT. It is a figure which shows one Embodiment of the abnormality determination apparatus of the internal combustion engine which concerns on this invention, and is a flowchart of an abnormality determination process. It is a figure which shows one Embodiment of the abnormality determination apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the pressure pulsation when an oil level is appropriate. It is a figure which shows one Embodiment of the abnormality determination apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the pressure pulsation when an oil level falls.

Embodiments of an abnormality determination device for an internal combustion engine according to the present invention will be described below with reference to the drawings.
1 to 7 show an embodiment of an abnormality determination device for an internal combustion engine according to the present invention.
First, the configuration will be described.
In FIG. 1, a vehicle 1 includes an engine 2 as an internal combustion engine, an oil supply device 3, and an abnormality determination device 4 for the internal combustion engine.

  As shown in FIG. 2, the engine 2 performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston 5 accommodated in a cylinder (not shown) so as to be able to reciprocate is reciprocated twice. It is a so-called 4-cycle gasoline engine.

  The engine 2 is an in-line 4-cylinder engine having four cylinders and four pistons 5 each. The number of cylinders is an example, and is not limited to four cylinders. The engine 2 is not limited to a gasoline engine but may be a diesel engine.

  The engine 2 includes an engine block including a piston 5, a variable valve timing mechanism (hereinafter referred to as VVT) 22, a crankshaft 6 constituting an output shaft, a cylinder head head 7, a cylinder block 8, and a crankcase. 9 and a fuel injection device (not shown) for injecting fuel into the cylinder.

  The crankshaft 6 is rotatably supported by the engine block 9 via a crank journal 6a. The crankshaft 6 is connected to the piston 5 via a connecting rod 10 so that the reciprocating motion of the piston 5 is transmitted to rotate. The connecting rod 10 is connected to the crankpin 6b of the crankshaft 6.

The intake camshaft 20 and the exhaust camshaft 21 constituting the camshaft are rotatably supported by the cylinder head 7 via a cam journal 19 (see FIG. 3).
The intake camshaft 20 and the exhaust camshaft 21 are connected to the crankshaft 6 via a chain 25. When the power of the crankshaft 6 is transmitted via the chain 25, the intake camshaft 20a and the exhaust cam 21a are connected. The intake valve 23 and the exhaust valve 24 are opened and closed.

  As shown in FIGS. 1 and 2, the oil supply device 3 includes an oil pan 11, an oil strainer 12, an oil pump 13, an oil filter 14 that filters oil discharged from the oil pump 13, and an oil passage 15a. And an oil supply path 15 (see FIG. 3) including an oil recirculation path 15b.

An oil strainer 12 is immersed in the oil pan 11, and the oil strainer 12 filters oil stored in the oil pan 11.
The oil stored in the oil pan 11 is sucked up by the oil pump 13 through the oil strainer 12 and discharged from the oil pump 13 to the oil passage 15a. An oil filter 14 is interposed in the oil passage 15a, and the oil filter 14 removes foreign matters mixed in the oil.

  The oil pump 13 is composed of, for example, a trochoid pump or a gear pump, and is connected to the crankshaft 6 via a chain. The oil pump 13 is driven at a constant speed by the crankshaft 6 on a separate axis from the crankshaft 6. Yes. The oil pump 13 may have a structure that is directly connected to the crankshaft 6 and driven at a constant speed by the crankshaft 6 without using a chain.

  As shown in FIGS. 2 and 3, a main gallery 17 is provided downstream of the oil passage 15 a, and the main gallery 17 extends along the crankshaft 6 in the wall surface of the cylinder block 8. The main gallery 17 is supplied with oil pressurized by the oil pump 13, and the oil supplied to the main gallery 17 is branched and supplied to the cylinder head 7 and the cylinder block 8. It has become.

The oil branched and supplied to the cylinder head 7 and the cylinder block 8 is supplied to each supply site of the engine 2.
For example, in the cylinder block 8, the cylinder journal 6 a and the crank pin 6 b of the crankshaft 6, the lubricating oil for the sliding parts such as the connecting rod 10, and the hydraulic oil for the oil jet 18 constituting the hydraulic drive part are used as the cylinder In the head 7, the oil is used for lubricating the cam journal 19 of the intake camshaft 20 and the exhaust camshaft 21, and the operating oil of the VVT 22 and the lash adjuster 27 constituting the hydraulic drive parts.

  In the present embodiment, the parts to be supplied include lubrication parts such as the crank journal 6a, the crank pin 6b, the connecting rod 10, and the piston 5, the oil jet 18 that supplies oil to the piston 5, the lash adjuster 27, the VVT 22, and the like. It consists of hydraulic drive parts.

  Here, the oil jet 18 injects oil toward the bottom surface of the piston 5 of the engine 2 to cool the piston 5 that is exposed to the combustion gas and has a high thermal load. This prevents combustion and suppresses knocking.

  The oil supplied to each supply site is then dropped inside the engine block 9 and returned to the oil pan 11 again. The oil supply path 15 of the oil supply device 3 includes an oil passage 15 a, an oil recirculation path 15 b, and a main gallery 17, and supplies the oil stored in the oil pan 11 to each supplied part of the engine 2. Later, it is configured as a circulation path for recovery to the oil pan 11.

  That is, the oil supply path 15 is an oil circulation path until the oil stored in the oil pan 11 is supplied to each supply site of the engine 2 by the oil pump 13 and then collected in the oil pan 11.

  The oil pump 13 is composed of, for example, a trochoid pump, a gear pump, and the like, and is connected to a crankshaft 6 that is an output shaft of the engine 2 via a chain 25, and is separated from the crankshaft 6 by a crankshaft 6. It is driven at a constant speed. The oil pump 13 may be driven coaxially with the crankshaft 6 via the chain 25.

  The oil pump 13 is configured to generate pressure pulsations having a pressure fluctuation range when oil is discharged. Specifically, when the oil pump 13 is a trochoid pump, the center of the inner rotor and the outer rotor is eccentric from each other, and the number of teeth of the inner rotor is one sheet from the number of teeth of the outer rotor. The space between the inner rotor and the outer rotor is enlarged and reduced by the rotation of the inner rotor, so that the pumping action is performed.

Since the space defined by one tooth of the inner rotor and one tooth of the outer rotor faces the discharge port in a compressed state, high pressure oil is discharged at the time of discharge, and the next one tooth of the inner rotor And high pressure oil is discharged again when the space defined by the teeth of the outer rotor faces the discharge port. Then, the pressure is low between the discharge of the high pressure oil and the next discharge of the high pressure oil.
For this reason, oil pressure fluctuations, that is, pressure pulsations are generated by alternately repeating high and low pressures of oil as the inner rotor rotates.

  On the other hand, the VVT 22 is provided at an end portion of the intake camshaft 20 and, as shown in FIG. 4, a housing 31 as a first rotating body connected to the crankshaft 6 via a chain 25, and the housing 31. And a vane body 32 as a second rotating body that rotates integrally with the intake camshaft 20.

  An advance side hydraulic chamber 33 and a retard side hydraulic chamber 34 defined by the housing 31 and the vane body 32 are formed inside the housing 31, and the VVT 22 includes an advance side hydraulic chamber 33 and a retard side hydraulic chamber. By changing the volume ratio of 34, the vane body 32 can be rotated with respect to the housing 31, the rotational phase of the intake camshaft 20 with respect to the crankshaft 6 can be changed, and the valve timing of the intake valve 23 is changed. be able to.

  When the vane body 32 rotates relative to the housing 31 so that the volume of the advance side hydraulic chamber 33 increases and the volume of the retard side hydraulic chamber 34 decreases, the valve timing is advanced.

  Further, when the vane body 32 rotates relative to the housing 31 so that the volume of the retard side hydraulic chamber 34 increases and the volume of the advance side hydraulic chamber 33 decreases, the valve timing is retarded.

  The VVT 22 selectively supplies oil (operating oil) to either the advance-side hydraulic chamber 33 or the retard-side hydraulic chamber 34, so that the advance-side hydraulic chamber 33 and the retard-side hydraulic chamber 34 The volume ratio can be changed.

  When oil is supplied to the advance side hydraulic chamber 33, the advance side hydraulic chamber 33 is expanded by the amount of the supplied oil, and the advance side hydraulic chamber 33 is expanded from the retard side hydraulic chamber 34. Along with this, oil is pushed out. Conversely, when oil is supplied to the retarded hydraulic chamber 34, the retarded hydraulic chamber 34 expands by the amount of the supplied oil, and the advanced hydraulic chamber 33 shrinks as the oil is pushed out. To do.

  Further, the VVT 22 is provided with a holding mechanism for locking the operation of the VVT 22. The holding mechanism includes a lock pin 35 provided in the vane body 32 of the VVT 22 and a lock hole 36 formed in the housing 31.

  When the lock pin 35 is engaged with the lock hole 36, the vane body 32 is fixed to the housing 31 at a predetermined rotation angle, that is, at a predetermined position.

  In this embodiment, the lock hole 36 is provided at a position where the valve timing is most retarded. When the valve timing is retarded most, the lock pin 35 is fitted into the lock hole 36 and the vane body 32 is accommodated in the housing. Rotation with respect to 31 is restricted.

  That is, the vane body 32 is fixed to the housing 31, and the vane body 32 is held by the housing 31. The lock pin 35 is urged in the direction of the lock hole 36 by a coil spring (not shown) or the like, and resists the urging force of the coil spring when the hydraulic pressure supplied to the retard angle side hydraulic chamber 34 exceeds a predetermined hydraulic pressure. Then, it comes out of the lock hole 36. At this time, the vane body 32 is rotatable relative to the housing 31.

  The driving force for driving the lock pin 35 in the holding mechanism is a biasing force of a spring (not shown) built in the vane body 32 and a hydraulic pressure supplied to the VVT 22. The urging force of the spring acts in a direction to push the lock pin 35 into the lock hole 36, and the hydraulic pressure acts in a direction to push the lock pin 35 out of the lock hole 36.

  The oil supplied to the VVT 22 is extracted from the main gallery 17 through the VVT passage 37.

  An oil control valve (hereinafter simply referred to as OCV) 38 is attached to the tip of the VVT passage 37. The OCV 38 and the advance side hydraulic chamber 33 of the VVT 22 are connected by a hydraulic passage 39, and the OCV 38 and the retard side hydraulic chamber 34 of the VVT 22 are connected by a hydraulic passage 40.

  The OCV 38 is a passage switching valve that switches the oil supply destination between the hydraulic passage 39 and the hydraulic passage 40, and at the same time, is a flow rate adjustment valve that can adjust the oil supply amount by controlling the opening.

  Specifically, the OCV 38 is an electromagnetically driven spool valve, and can control the supply and discharge of oil to and from the hydraulic passage 39 and the hydraulic passage 40 according to the position of the spool in the sleeve. The spool has one end in the moving direction supported by a spring and the other end supported by a solenoid.

  The position of the spool can be controlled by the duty ratio of the drive current supplied to the solenoid. When the solenoid is not energized, the spool is placed at a predetermined initial position by the biasing force of the spring. In this initial position, the VVT passage 37 is connected to the hydraulic passage 40.

  As shown in FIG. 1, the oil recirculation passage 15b is connected to the oil passage 15a on the discharge side of the oil pump 13, and a relief valve 26 is provided on the oil recirculation passage 15b. The relief valve 26 operates (opens) when the oil pressure (discharge pressure) on the discharge side of the oil pump 13 exceeds a predetermined value, and relieves oil into the oil pan 11 or the oil pump 13.

  As shown in FIGS. 1 and 4, the abnormality determination device 4 includes a hydraulic pressure sensor 41, an electronic control unit (hereinafter referred to as ECU) 44, and a warning lamp 45.

  The oil pressure sensor 41 constitutes oil pressure detecting means, and is provided in the oil passage 15 a on the discharge side of the oil pump 13. The hydraulic sensor 41 detects the hydraulic pressure supplied from the oil pump 13 to hydraulic drive components such as the VVT 22 and the sliding part of the engine 2 and outputs a signal corresponding to the hydraulic pressure to the ECU 44. Note that the hydraulic sensor 41 may be provided in the main gallery 17.

  An intake pipe 46 for introducing intake air to the engine 2 is connected to the engine 2, and the intake pipe 46 is provided with a throttle valve 42. The throttle valve 42 adjusts the amount of intake air introduced into the engine 2 by adjusting the opening of the intake pipe 46.

  The throttle valve 42 is driven by a drive motor 43, and the drive motor 43 adjusts the opening degree of the throttle valve 42 based on a drive signal from the ECU 44.

  The intake pipe 46 introduces intake air into the combustion chamber of the cylinder via an intake port formed in the cylinder head 7, and the intake port is opened and closed by the intake valve 23. Yes.

  The ECU 44 is connected to a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), an input interface to which the hydraulic sensor 41 is connected, an OCV 38, a drive motor 43, and a warning lamp 45. Output interface.

  The RAM temporarily stores data and functions as a work area. The ROM stores various control programs including an abnormality determination program, a map referred to when executing these various control programs, and the like.

  In addition, a threshold value is stored in the ROM, and this threshold value is set to a value corresponding to the magnitude of the fluctuation range of the pressure pulsation of the oil discharged from the oil pump 13 (for example, 50 kPa).

  The ECU 44 calculates the magnitude of the fluctuation range of the discharge pressure of the oil pump 13 based on the detection information of the hydraulic sensor 41, and determines that the hydraulic pressure is abnormal when it is determined that the fluctuation range is less than a predetermined threshold value. It is supposed to be. In the present embodiment, the ECU 44 constitutes an abnormality determination unit.

  When the ECU 44 determines that the hydraulic pressure is abnormal, the ECU 44 outputs an abnormal signal to the warning lamp 45. The warning lamp 45 is a warning lamp that warns that an oil pressure abnormality has occurred and the oil level in the oil pan 11 has decreased.

  The warning lamp 45 is lit or blinked when an abnormal signal is input from the ECU 44 to warn of an abnormal hydraulic pressure, thereby warning the driver that the oil level in the oil pan 11 has decreased.

  When the ECU 44 determines that the hydraulic pressure is abnormal, the ECU 44 transmits a control signal to the drive motor 43. When the control signal is input from the ECU 44, the drive motor 43 controls the throttle valve 42 to the closed side. As a result, the engine 2 is prevented from increasing to a predetermined speed or higher.

  When determining that the hydraulic pressure is abnormal, the ECU 44 controls the OCV 38 to supply oil to the advance side hydraulic chamber 33 and discharge the oil from the retard side hydraulic chamber 34, whereby the lock pin 35 enters the lock hole 36. Holding control for rotating the vane body 32 with respect to the housing 31 so as to be locked is performed.

Next, the abnormality determination process for the engine 2 will be described with reference to FIGS.
FIG. 5 illustrates an abnormality determination process executed by the ECU 44 of the abnormality determination device 4. The flowchart in FIG. 5 is an abnormality determination program stored in the ROM, and this abnormality determination program is executed by the CPU at regular intervals.

  In FIG. 5, the CPU of the ECU 44 detects the pressure of the oil discharged from the oil pump 13 based on the detection information of the hydraulic pressure sensor 41 (step S1), and the threshold value Pi in which the fluctuation range P of this oil is stored in the ROM. It is determined whether it is less than (step S2).

  When the CPU of the ECU 44 determines that the fluctuation range P of the oil pressure pulsation is greater than or equal to the threshold value Pi, it determines that the oil level of the oil pan 11 is an appropriate amount and ends the current process. .

  That is, as shown in FIG. 6, when the oil level of the oil pan 11 is an appropriate amount, the air suction of the oil pump 13 is small, so that the pressure pulsation of the oil discharged from the oil pump 13 is reduced. growing.

  Therefore, when the CPU of the ECU 44 determines that the fluctuation range P of the oil pressure pulsation is equal to or greater than the threshold value Pi, it can determine that the oil level of the oil pan 11 is an appropriate amount.

  On the other hand, if the CPU of the ECU 44 determines in step S2 that the fluctuation range P of the oil pressure pulsation is less than the threshold value Pi, it determines that the oil level of the oil pan 11 has decreased, that is, has been insufficient. To do.

  That is, as shown in FIG. 7, when the oil level in the oil pan 30 decreases, the oil pump 13 enters an air sucking state, the bubbles contained in the oil increase, and the oil pump 13 bites the bubbles. Causes biting.

  When the oil pump 13 causes the air to bite, the vibration generated when the oil pump 13 bites the bubbles becomes pressure pulsation. Since this pressure pulsation is the entrapment of bubbles when the amount of oil sucked into the oil pump 13 is small, the fluctuation range is smaller than the pressure pulsation when the oil level is normal.

  Accordingly, when the CPU of the ECU 44 determines that the fluctuation range P of the oil pressure pulsation is less than the threshold value Pi, it can determine that the oil level of the oil pan 11 has decreased.

  When the CPU of the ECU 44 determines in step S2 that the fluctuation range P of the oil pressure pulsation is less than the threshold value Pi, it outputs an abnormal signal to the warning lamp 45 (step S3) and turns on the warning lamp 45. Let

  After outputting an abnormal signal to the warning lamp 45, the CPU of the ECU 44 performs holding control of the VVT 22 (step S4).

  Specifically, the OCV 38 is configured such that when the solenoid is not energized, the VVT passage 37 is connected to the hydraulic passage 40 by the biasing force of the spring of the spool. For this reason, the CPU of the ECU 44 energizes the solenoid after outputting the abnormality signal. When the solenoid is energized, the spool moves against the biasing force of the spring so as to connect the VVT passage 37 to the hydraulic passage 39.

  Since the hydraulic passage 39 communicates with the advance side hydraulic chamber 33, when the VVT passage 37 is connected to the hydraulic passage 39, the hydraulic passage 39 is discharged from the oil pump 13 and supplied to the VVT passage 37 via the main gallery 17. Oil is supplied to the advance side hydraulic chamber 33 through the hydraulic passage 39, and the oil in the retard side hydraulic chamber 34 is discharged from the retard side hydraulic chamber 34 to the OCV 38.

Therefore, the volume of the advance side hydraulic chamber 33 is increased and the volume of the retard side hydraulic chamber 34 is reduced, so that the vane body 32 moves relative to the housing 31 so that the lock pin 35 is fitted in the lock hole 36. The lock pin 35 is fitted into the lock hole 36.
Accordingly, the lock pin 35 is held by the housing 31 so that the vane body 32 does not rotate with respect to the housing 31.

  Next, the CPU of the ECU 44 outputs a control signal to the drive motor 43, thereby controlling the throttle valve 42 to the closed side by the drive motor 43 (step S5), and ends the current process.

  The control to the closed side of the throttle valve is controlled to the closed side with respect to the opening degree of the throttle valve associated with depression of an accelerator pedal (not shown). Therefore, the rotational speed of the engine 2 does not rise above the predetermined rotational speed. That is, the CPU of the ECU 44 refers to a map in which the opening degree of the accelerator pedal and the opening degree of the throttle valve are associated with each other, and controls the throttle opening degree closer to the closing side than the normal opening degree of the throttle valve. If it does in this way, the amount of intake air supplied to engine 2 will decrease and the increase in the number of rotations of engine 2 will be controlled.

As described above, the ECU 44 according to the present embodiment determines that the oil pressure is abnormal on the condition that the fluctuation range of the pressure pulsation of the oil discharged from the oil pump 13 is less than a predetermined threshold value. Based on the magnitude of the pressure pulsation, it can be estimated that the ratio of bubbles mixed in the oil has increased.
As a result, it can be detected at an early stage that the oil level in the oil pan 11 has been lowered, and the protection of the portion to be supplied can be realized at an early stage.

  Further, since the ECU 44 controls the rotation speed of the engine 2 so that the rotation speed of the engine 2 does not exceed a predetermined rotation speed as protection of the supplied part, the crank journal 23a, the crank pin 23b, the connecting rod 21a, The engine 2 can be protected by preventing the piston 5 and the like from burning.

  Further, as the protection of the supplied portion, the ECU 44 performs holding control that restricts the rotation of the vane body 32 of the VVT 22 with respect to the housing 31, so that the vane body 32 collides with the housing 31. This can be prevented.

  That is, the VVT 22 of the present embodiment includes an OCV 38 that selectively supplies oil discharged from the oil pump 13 to the advance side hydraulic chamber 33 and the retard side hydraulic chamber 34, and the VVT 22 includes the vane body 32 in the housing. A lock pin 35 and a lock hole 36 are provided to hold the vane body 32 in the housing 31 when the vane body 32 is rotated to the retarded angle side which is a predetermined position with respect to 31.

  As the holding control, the ECU 44 controls the OCV 38 to adjust the hydraulic pressure supplied to the advance side hydraulic chamber 33 and the retard side hydraulic chamber 34 so that the vane body 32 rotates to the retard side. Since the vane body 32 is held in the housing 31 by fitting the lock pin 35 into the lock hole 36, the vane body 32 can be securely held in the housing 31, and the vane body 32 collides with the housing 31. Can be prevented. For this reason, it is possible to prevent the behavior of the VVT 22 from deteriorating.

  Further, the ECU 44 according to the present embodiment outputs an abnormal signal to the warning lamp 45 on the condition that the fluctuation range of the pressure pulsation of the oil discharged from the oil pump 13 is less than a predetermined threshold value Pi. The lamp 45 is turned on or blinked.

  For this reason, it is possible to warn the driver that the oil level in the oil pan 11 has decreased. Therefore, it is possible to prompt the driver to check the oil in the oil pan 11 or to replenish the oil pan 11 with oil.

  The abnormality determination device 4 is provided with an oil temperature sensor that detects the temperature of the oil, and the ECU 44 has a fluctuation range P of the oil pressure pulsation that is less than the threshold Pi based on the detection information of the oil pressure sensor 41 and the oil temperature sensor. If it is determined, it may be determined that the hydraulic pressure is abnormal.

  That is, when the temperature of the oil is low, such as during warm-up operation, the viscosity of the oil is high, and when the temperature of the oil is high, the viscosity of the oil is low. For this reason, when the oil level in the oil pan 11 is lowered, there are fewer bubbles mixed in the oil when the oil temperature is lower than when the oil temperature is high.

  Therefore, the ECU 44 sets a first threshold value when the oil temperature is high and a second threshold value smaller than the first threshold value when the oil temperature is low, and changes the threshold value according to the oil temperature. Thus, by comparing the threshold value corresponding to the oil temperature and the oil pressure pulsation, the oil pressure abnormality can be determined more accurately.

  As described above, the abnormality determination device for an internal combustion engine according to the present invention can quickly detect that the oil level has decreased by estimating that the bubble rate has increased from the magnitude of the pressure pulsation of the discharge pressure of the oil pump. It has an effect that it can be detected, and is useful as an abnormality determination device for an internal combustion engine that determines an abnormality in oil pressure caused by a decrease in oil level.

2 Engine (Internal combustion engine)
4 Abnormality determination device 5 Piston (part to be supplied)
6 Crankshaft (output shaft)
6a Crank journal (supplied part)
6b Crank pin (supplied part)
10 Connecting rod (part to be supplied)
11 Oil pan (oil storage means)
13 Oil pump 18 Oil jet (supplied part)
19 Cam journal (supplied part)
20 Intake camshaft (camshaft)
22 VVT (parts to be supplied)
27 Rush adjuster (supplied part)
31 Housing (first rotating body)
32 Vane body (second rotating body)
33 Advance-side hydraulic chamber 34 Delay-side hydraulic chamber 41 Hydraulic sensor (hydraulic detection means)
44 ECU (abnormality determination means)
45 Warning lamp (Warning means)

Claims (3)

An abnormality determination device for an internal combustion engine having an oil pump that supplies oil stored in an oil storage means to a supply site,
Oil pressure detection means for detecting the pressure of oil discharged from the oil pump;
An abnormality determining unit that determines that the oil pressure is abnormal on the condition that a fluctuation range of pressure pulsation of oil discharged from the oil pump is less than a predetermined threshold based on detection information of the oil pressure detecting unit; The
The to-be-supplied portion rotatably accommodates a second rotating body connected to a camshaft inside a first rotating body connected to an output shaft of the internal combustion engine, and the first rotating body and the Variable valve timing for varying the relative rotational phase between the camshaft and the output shaft by selectively supplying the hydraulic pressure of the advance side hydraulic chamber and the retard side hydraulic chamber partitioned by the second rotating body. Including the mechanism,
The abnormality determination unit is configured such that the second rotating body is compared with the first rotating body on the condition that a fluctuation range of pressure pulsation of oil discharged from the oil pump is less than a predetermined threshold. Holding control to regulate the rotation,
The holding control locks the second rotating body to the first rotating body by supplying the oil to the advance side hydraulic chamber and discharging the oil from the retard side hydraulic chamber. abnormality determination device for an internal combustion engine, characterized in that it. Warning means for giving a warning based on an abnormality signal output from the abnormality determination means;
The abnormality determination means outputs the abnormality signal to the warning means on condition that a fluctuation range of pressure pulsation of oil discharged from the oil pump is less than a predetermined threshold value. Item 6. An abnormality determination device for an internal combustion engine according to Item 1.   The abnormality determination means is configured so that the rotational speed of the internal combustion engine does not exceed a predetermined rotational speed on condition that a fluctuation range of pressure pulsation of oil discharged from the oil pump is less than a predetermined threshold value. The abnormality determination device for an internal combustion engine according to claim 1 or 2, wherein the number of revolutions of the internal combustion engine is controlled.

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