JP5887876B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that protects the variable valve timing mechanism when an oil pressure supplied to the variable valve timing mechanism is abnormal.

  In an internal combustion engine (hereinafter also referred to as an engine) mounted on a vehicle or the like, rotation of a crankshaft is transmitted to a camshaft via a timing chain or the like. The engine valve (intake valve / exhaust valve) of the engine is periodically pushed down by the cam of the camshaft and reciprocates to open and close the intake passage and the exhaust passage.

  In this type of engine, the rotational phase of the camshaft relative to the crankshaft is always constant. On the other hand, in recent years, a variable valve timing mechanism (VVT: Variable Valve Timing) is mounted on the engine.

This variable valve timing mechanism is a mechanism for changing the opening / closing timing of the engine valve by changing the rotational phase of the camshaft with respect to the crankshaft for the purpose of improving engine output, improving fuel consumption, and reducing exhaust emissions.
For example, the variable valve timing mechanism includes a housing and a vane body that divides the housing into an advance hydraulic chamber and a retard hydraulic chamber, and the housing is connected to the crankshaft and the vane body is connected to the camshaft. In this state, the hydraulic pressure supplied to the advance side hydraulic chamber and the retard side hydraulic chamber is controlled by an oil control valve (OCV), thereby shifting the rotation phase between the crankshaft and the camshaft and thereby controlling the opening / closing timing of the engine valve. It has a structure that changes continuously.

  An oil pump that is driven to rotate as the engine rotates is connected to the upstream side of the oil control valve. When the oil pump is driven, the oil stored in the oil pan is sucked into the strainer.

  The oil sucked into the strainer is selectively supplied to the advance hydraulic chamber or the retard hydraulic chamber via the OCV, and the camshaft and the housing are changed by changing the relative rotational phase between the housing and the vane body. Relative rotation phase, that is, the valve timing is varied.

  By the way, when the oil level (oil level height) stored in the oil pan decreases with respect to an appropriate amount, the strainer for sucking oil from the oil pan to the oil pump is in a state of sucking air (hereinafter, this state). May be called air suction).

  When the oil pump is in the air sucking state, the hydraulic pressure supplied to the VVT is reduced, so that the vane body cannot be stably held against the housing, and the vane body strongly collides with the inner wall of the housing. A loud hitting sound may be generated, and the durability between the vane body and the housing may be deteriorated.

  A valve timing control device for an internal combustion engine as disclosed in Patent Document 1 is known as one that can suppress the occurrence of a large hitting sound due to the vane body strongly colliding with the inner wall of the housing when the hydraulic pressure is lowered.

  This valve timing control device for an internal combustion engine cuts off the communication between the oil pump and the advance side hydraulic chamber and the retard side hydraulic chamber of the VVT when the oil pressure detected by the oil pressure sensor is less than a predetermined value. The backflow of the oil in the corner side hydraulic chamber and the retard side hydraulic chamber is prevented, and the vane body is stably held with respect to the housing. For this reason, it can suppress that a vane body collides with the inner wall of a housing strongly at the time of a hydraulic pressure fall, and a loud sound is generated.

JP-A-11-141359

  However, in such a conventional control device for an internal combustion engine, when the hydraulic pressure is less than a predetermined value, the communication between the oil pump and the advance side hydraulic chamber and the retard side hydraulic chamber of the VVT is cut off to the housing. In contrast, the vane body is restrained from rotating, but the communication between the oil pump and the advance side hydraulic chamber and the retard side hydraulic chamber of the VVT is not cut in consideration of the bubble rate. The rotation of the vane body cannot be sufficiently suppressed.

  That is, even when the oil pressure is equal to or higher than a predetermined value, the vane body is moved left and right by the oil having a high bubble rate supplied to the advance side hydraulic chamber and the retard side hydraulic chamber when the bubble rate mixed into the oil is high. A phenomenon occurs in which the vane body cannot be stably held in the housing. As a result, there is a problem that drivability deteriorates.

  The present invention has been made in order to solve the above-described conventional problems, and the second rotating body is held in the first rotating body at an early stage based on the bubble rate and oil pressure mixed in the oil. It is an object of the present invention to provide a control device for an internal combustion engine that can prevent the second rotating body from flapping and prevent drivability from deteriorating.

  In order to achieve the above object, a control device for an internal combustion engine according to the present invention includes (1) a second rotating body connected to a camshaft inside a first rotating body connected to an output shaft of the internal combustion engine. The hydraulic pressure of the advance side hydraulic chamber and the retard side hydraulic chamber that is rotatably accommodated and defined by the second rotating body is selectively supplied, so that the camshaft and the output shaft are relatively A control device for an internal combustion engine having a variable valve timing mechanism for changing a rotation phase, wherein a predetermined hydraulic pressure judgment value is set in accordance with a bubble rate mixed in oil and supplied to the variable valve timing mechanism The hydraulic pressure of the variable valve timing mechanism is determined to be abnormal on the condition that the hydraulic pressure to be applied is less than the determination value, and the second rotating body is restricted from rotating with respect to the first rotating body. Execute holding control Control means, and when the hydraulic pressure supplied to the variable valve timing mechanism is greater than or equal to the determination value, the control means is configured to detect an abnormal hydraulic pressure of the variable valve timing mechanism on the condition that the bubble rate is high. It is comprised from what determines and implements the said holding | maintenance control.

  The control device for an internal combustion engine is provided with a variable valve timing mechanism on condition that the hydraulic pressure supplied to the variable valve timing mechanism is less than a predetermined hydraulic pressure determination value according to the bubble rate mixed in the oil. Is determined, and holding control is performed to restrict the second rotating body from rotating relative to the first rotating body. Therefore, when the hydraulic pressure is low, the second rotating body is It is possible to prevent abnormal noise from colliding with the rotating body, and to prevent the first rotating body and the second rotating body from being damaged, and the durability of the variable valve timing mechanism is deteriorated. Can be prevented.

  Also, if the hydraulic pressure supplied to the variable valve timing mechanism is greater than or equal to the criterion value, the abnormality in the hydraulic timing of the variable valve timing mechanism is determined and the holding control of the variable valve timing mechanism is performed on the condition that the bubble rate is high. Therefore, it is possible to prevent the second rotating body from flapping with respect to the first rotating body and to prevent the drivability from deteriorating.

  In the control device for an internal combustion engine according to (1), (2) an oil supply member that selectively supplies oil discharged from an oil pump to the advance side hydraulic chamber and the retard side hydraulic chamber; The timing variable mechanism has a holding mechanism that holds the second rotating body on the first rotating body when the second rotating body rotates to a predetermined position with respect to the first rotating body. The control means controls the oil supply means to adjust the hydraulic pressure supplied to the advance side hydraulic chamber and the retard side hydraulic chamber so that the vane body rotates to the predetermined position. Thus, the above-described holding control is implemented.

  The control device for the internal combustion engine adjusts the hydraulic pressure supplied to the advance side hydraulic chamber and the retard side hydraulic chamber so that the vane body rotates to a predetermined position when the holding control is performed, Since the rotating body is held by the first rotating body, the second rotating body can be reliably held by the first rotating body.

  In the control device for an internal combustion engine according to (1) or (2), (3) oil pressure detection means for detecting the oil pressure supplied to the valve timing variable mechanism, and bubble rate acquisition for acquiring the bubble rate mixed in the oil And the control means is configured to implement the holding control based on information from the oil pressure detection means and the bubble rate acquisition means.

  The control device for the internal combustion engine can acquire the oil pressure and the bubble rate information based on the information from the oil pressure detection unit and the bubble rate acquisition unit, and therefore can perform the holding control based on the oil pressure and the bubble rate. it can.

  In the control apparatus for an internal combustion engine of (1) to (3), (4) warning means for giving a warning based on the abnormal signal output from the control means is provided, and the control means includes the valve timing variable mechanism. On the condition that the hydraulic pressure supplied to is less than the determination value, the abnormal signal is output to the warning means.

  When the hydraulic pressure supplied to the variable valve timing mechanism is less than the determination value, this internal combustion engine control device outputs an abnormal signal to the warning means. For example, the oil stored in the oil pan has decreased. Can be reliably detected and warned.

  As a result, the driver is encouraged to change the oil in the oil pan, and after the oil change, the hydraulic pressure that can stably hold the second rotating body to the first rotating body with respect to the variable valve timing mechanism. Can be supplied.

  According to the present invention, the second rotating body flutters in such a manner that the second rotating body can be held on the first rotating body at an early stage based on the bubble ratio and oil pressure mixed in the oil. Therefore, it is possible to provide a control device for an internal combustion engine that can prevent drivability from deteriorating.

1 is a diagram showing an embodiment of a control device for an internal combustion engine according to the present invention, and is a schematic configuration diagram of a vehicle including the control device for an internal combustion engine. 1 is a diagram showing an embodiment of a control device for an internal combustion engine according to the present invention, and is a schematic perspective view of the engine. FIG. It is a figure which shows one Embodiment of the control apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the block diagram of the supply route of the oil which supplies oil to VVT, and a control circuit. It is a figure which shows one Embodiment of the control apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows an abnormality determination map. It is a figure which shows one Embodiment of the control apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows a bubble rate determination map. It is a figure which shows one Embodiment of the control apparatus of the internal combustion engine which concerns on this invention, and is a flowchart of an abnormality determination program. It is a figure which shows one Embodiment of the control apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows another bubble rate determination map.

Embodiments of an internal combustion engine control apparatus according to the present invention will be described below with reference to the drawings.
FIGS. 1-7 is a figure which shows one Embodiment of the control apparatus of the internal combustion engine which concerns on this invention.
First, the configuration will be described.
1 and 2, a vehicle 1 includes an engine 2 as an internal combustion engine, an oil supply device 3, and a control 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.

  As shown in FIGS. 1 and 2, the oil supply device 3 filters an oil pan 11, an oil strainer 12, an oil pump 13, and engine oil (hereinafter simply referred to as oil) discharged from the oil pump 13. An oil filter 14, an oil passage 15, and an oil recirculation passage 16 are included.

  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 15. An oil filter 14 is interposed in the oil passage 15, 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 FIG. 2, a main gallery 17 is provided downstream of the oil passage 15, 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 7 a serves as the lubricating oil for the crank journal 6 a and the crank pin 6 b of the crankshaft 6, and the oil jet 18 that constitutes the hydraulic drive parts of the lubricating portion such as the connecting rod 10. Is used as lubricating oil for the cam journals 20a and 21a of the intake camshaft 20 and the exhaust camshaft 21 as camshafts, and as hydraulic oil for a valve timing variable mechanism (hereinafter simply referred to as VVT) 22 constituting a hydraulic drive component.

  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 cam journals 20a and 21a are located between the intake cam 20b and the exhaust cam 21b, and are portions that rotatably support the intake camshaft 20 and the exhaust camshaft 21 on the cylinder head 7.

  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 20b and the exhaust cam 21b are connected. The intake valve 23 and the exhaust valve 24 are opened and closed.

  On the other hand, the VVT 22 is provided at an end portion of the intake camshaft 20, and as shown in FIG. 3, a housing 31 as a first rotating body connected to the crankshaft 6 via a chain 25, and a housing 31 And a vane body 32 as a second rotating body that rotates integrally with the intake camshaft 23.

  An advance side hydraulic chamber 33 and a retard side hydraulic chamber 34 defined by a vane body 32 are formed inside the housing 31, and the VVT 22 has a volume of the advance side hydraulic chamber 33 and the retard side hydraulic chamber 34. By changing the ratio, 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 can be changed. .

  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 the urging force of a spring (not shown) built in the vane body 32 and the hydraulic pressure of oil 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 oil pressure of the oil acts in a direction to push out the lock pin 35 from 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 16 is connected to the oil passage 15 on the discharge side of the oil pump 13, and a relief valve 26 is provided on the oil recirculation passage 16. 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 3, the control device 4 includes a hydraulic pressure sensor 41, an oil temperature sensor 42, an engine speed sensor 43, an electronic control unit (hereinafter referred to as ECU) 44, and a warning lamp 51. It consists of

  The oil pressure sensor 41 constitutes oil pressure detecting means, and is provided in the oil passage 15 on the discharge side of the oil pump 13. The hydraulic sensor 41 detects the hydraulic pressure supplied from the oil pump 13 to the hydraulic drive components such as the VVT 22 and the lubrication 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.

  The engine speed sensor 43 detects the engine speed (rpm) based on the rotation angle of the crankshaft 6. The engine speed sensor 43 is connected to the ECU 44 and outputs a signal corresponding to the detected engine speed (rpm) to the ECU 44.

  The oil temperature sensor 42 constitutes an oil temperature detecting means and detects the temperature of oil discharged from the oil pump 13. The oil temperature sensor 42 is provided in the oil passage 15 on the discharge side of the oil pump 13 and is electrically connected to the ECU 44. The oil temperature sensor 42 may be provided in the oil pan 11 or the main gallery 17.

  The oil temperature sensor 42 is constituted by, for example, a thermistor whose resistance value changes according to the temperature, and outputs a voltage that changes according to the change of the resistance value to the ECU 44 as a signal representing the oil temperature. .

  As shown in FIG. 3, the ECU 44 includes a CPU (Central Processing Unit) 45, a ROM (Read Only Memory) 46, a RAM (Random Access Memory) 47, a hydraulic pressure sensor 41, an oil temperature sensor 42, and an engine speed sensor. 43 includes an input interface 48 connected to 43, and an output interface 49 connected to the OCV 38 and the warning lamp 51.

  The ROM 46 stores various control programs including an abnormality determination program, a map referred to when executing these various control programs, and the like.

The ROM 46 stores an abnormality determination map 52 as a control map. As shown in FIG. 4, the abnormality determination map 52 is set with hydraulic pressure determination values P < b > 1 and P <b> 2 that are determined in advance according to the bubble ratio mixed in the oil.

  In the abnormality determination map 52, an area where the oil pressure is less than the determination value P1 is set as an abnormality area. When the ECU 44 determines that the oil pressure is less than the determination value P1, the abnormality of the oil pressure supplied to the VVT 22 is determined. Is determined.

  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 when the hydraulic pressure is abnormal, so that the lock pin 35 is locked in the lock hole 36. The holding control for rotating the vane body 32 with respect to the housing 31 is performed.

Further, when the hydraulic pressure is equal to or higher than the determination value P1, the abnormality determination map 52 indicates a holding unstable region (“holding stability” in FIG. 4) as a determination region of abnormality of the hydraulic pressure supplied to the VVT 22 based on the bubble rate . "Deterioration") is assigned, and when the oil pressure is equal to or greater than the determination value P2, the normal region is assigned.

That is, in the region where the oil pressure is equal to or higher than the determination value P1, even if the oil pressure is the same , if the air bubble rate is low due to the oil pressure determination value P2 corresponding to the air bubble rate, a normal region where the oil pressure is normal is assigned. When the bubble rate is high, a holding unstable region is assigned.

  When it is determined that the hydraulic pressure is equal to or higher than the determination value P1, the ECU 44 can determine that the hydraulic pressure supplied to the VVT 22 is abnormal based on the bubble rate. The ECU 44 performs the above-described holding control of the OCV 38 when the hydraulic pressure is abnormal.

  Further, when the ECU 44 determines that the values of the oil pressure and the bubble ratio are in the normal region based on the abnormality determination map 52, the ECU 44 determines that the oil pressure supplied to the VVT 22 is normal and performs the holding control. Not implemented. In the present embodiment, the ECU 44 constitutes a control means.

  That is, when the hydraulic pressure supplied to VVT 22 is less than determination value P1, ECU 44 of the present embodiment determines that VVT 22 has an abnormal hydraulic pressure, performs holding control, and determines the hydraulic pressure supplied to VVT 22 is the determination value. If it is greater than or equal to P1, it is determined that the VVT 22 has an abnormal hydraulic pressure on the condition that the bubble rate is high, and the holding control is performed.

  Further, the ROM 46 stores a bubble rate determination map 53 shown in FIG. The bubble rate determination map 53 stores the bubble rate and hydraulic pressure in association with each other at an arbitrary engine speed.

  When the oil level in the oil pan 11 is lowered, the oil strainer 12 sucks air, the bubble rate mixed in the oil sucked from the oil pan 11 by the oil pump 13 rises, and the hydraulic pressure is lowered. Based on the bubble rate determination map 53, the bubble rate can be estimated from the hydraulic pressure and the engine speed.

In the bubble rate determination map 53, the oil pressure and the bubble rate are assigned according to the engine speed, and the ROM 46 stores a plurality of bubble rate determination maps 53 according to the engine speed. In the present embodiment, the ROM 46, the hydraulic pressure sensor 41, and the engine speed sensor 43 constitute a bubble rate acquisition means.

  The warning lamp 51 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 51 is lit or blinked when an abnormality signal is input from the ECU 44 to warn of an abnormality in hydraulic pressure, thereby warning the driver that the oil level in the oil pan 11 has decreased.

  The ECU 44 outputs an abnormal signal to the warning lamp 51 when determining that the hydraulic pressure is in the abnormal region based on the abnormality determination map 52.

  Next, the abnormality determination control process executed by the ECU 44 of the control device 4 for the internal combustion engine will be described based on the flowchart of FIG. 6 is an abnormality determination program stored in the ROM 46.

  In FIG. 6, the CPU 45 stores the hydraulic pressure Pi in the RAM 47 based on the detection information from the hydraulic sensor 41 (step S <b> 1), and then stores the engine speed Ni in the RAM 47 based on the detection information from the engine speed sensor 43. (Step S2).

  Next, the CPU 45 refers to the bubble rate determination map 53 stored in the ROM 46 and estimates the bubble rate Ai based on the hydraulic pressure Pi and the engine speed Ni stored in the RAM 47 (step S3).

  Next, the CPU 45 refers to the abnormality determination map 52 stored in the ROM 46 and determines whether or not the hydraulic pressure Pi is greater than or equal to the determination value P1 (step S4). If the CPU 45 determines that the oil pressure Pi is less than the determination value P1, the CPU 45 determines that the oil level in the oil pan 11 has decreased and performs holding control (step S5).

  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 45 switches the VVT passage 37 so as to be connected to the hydraulic passage 39 against the biasing force of the spring by energizing the solenoid.

  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 oil passage 15. 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.

  Therefore, 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 45 outputs an abnormality signal to the warning lamp 51 to turn on the warning lamp 51 (step S6). For this reason, the driver can be warned that the oil level in the oil pan 11 has decreased, and the driver can be prompted to replace the oil.

  On the other hand, when it is determined that the hydraulic pressure P is greater than or equal to the determination value P1, it is determined whether or not the hydraulic pressure supplied to the VVT 22 is in a holding unstable region based on the bubble ratio Ai (step S7).

  When the CPU 45 determines that the air bubble rate is in a normal region with a low bubble rate relative to the hydraulic pressure with respect to FIG. If it is determined that it is in the area, the same holding control as in step S5 is performed (step S8), and the current process is terminated.

  In addition, you may move a process to the process which lights the warning lamp 51 after the process of step S8, ie, step S6.

  As described above, in the present embodiment, the hydraulic pressure supplied to the VVT 22 is less than the predetermined hydraulic pressure determination value P1 according to the bubble rate mixed in the oil, and the hydraulic pressure abnormality of the VVT 22 is detected. Since the determination and the holding control for restricting the rotation of the vane body 32 with respect to the housing 31 are performed, it is possible to prevent the noise generated by the vane body 32 colliding with the housing 31 when the hydraulic pressure is low. In addition, the vane body 32 and the housing 31 can be prevented from being damaged, and the durability of the VVT 22 can be prevented from deteriorating.

  Further, when the hydraulic pressure supplied to the VVT 22 is greater than or equal to the determination value P1, the VVT 22 is determined to be abnormal under the condition that the bubble rate is high, and the holding control of the VVT 22 is performed. It is possible to prevent fluttering with respect to 31 and prevent drivability from deteriorating.

  That is, the inventor of the present applicant, as shown in FIG. 4, in the abnormal region where the hydraulic pressure supplied to the VVT 22 is less than the predetermined value P <b> 1, the vane body 32 rotates greatly with respect to the housing 31. Phenomenon of the vane body 32 occurs relative to the housing 31 in an unstable holding region where the bubble ratio is high even if the housing 31 collides with the housing 31 and an abnormal noise occurs and the oil pressure supplied to the VVT 22 is equal to or greater than the predetermined value P1. I discovered that there is.

  In view of this phenomenon, even if the hydraulic pressure supplied to the VVT 22 is equal to or greater than the predetermined value P1, if the bubble rate is high, an abnormality in the hydraulic pressure of the VVT 22 is determined and the holding control of the VVT 22 is performed, thereby improving drivability. It can be prevented from getting worse.

  In the present embodiment, the VVT 22 includes an OCV 38 that selectively supplies the 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. It has a lock pin 35 and a lock hole 36 for holding the vane body 32 in the housing 31 when the vane body 32 is rotated to the retard side which is a predetermined position with respect to the housing 31.

  Then, 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. The vane body 32 is held in the housing 31 by being fitted in the lock hole 36.

  As a result, the vane body 32 can be reliably held in the housing 31, the vane body 32 can be reliably prevented from colliding with the housing 31, and the vane body 32 can be reliably prevented from flapping. Can do.

  Further, in the present embodiment, the ECU 44 acquires the bubble rate mixed into the oil based on the detection information from the hydraulic pressure sensor 41 and the engine speed sensor 43, so the bubble rate is reliably acquired and the holding control is performed. Can be implemented.

  In the present embodiment, the ECU 44 outputs an abnormal signal to the warning lamp 51 to light the warning lamp 51 when the hydraulic pressure is less than the predetermined value P1, so that the oil stored in the oil pan 11 is stored. It is possible to reliably detect and warn that the drop has occurred.

  As a result, it is possible to supply the hydraulic pressure that can stably hold the vane body 32 to the housing 31 to the VVT 22 after the oil is changed by urging the driver to change the oil in the oil pan 11.

  In the present embodiment, the bubble rate is estimated based on the hydraulic pressure and the engine speed, but the present invention is not limited to this. For example, the bubble rate may be acquired based on the bubble rate determination map 54 of FIG.

  In the bubble rate determination map 54 shown in FIG. 7, the oil pressure Po is assigned based on an arbitrary oil temperature (for example, 80 ° C.) and the engine speed, and the bubble rate at the oil pressure Po is normal (for example, the bubble rate is Zero). The ECU 44 acquires the change in hydraulic pressure with respect to the hydraulic pressure Po as the bubble rate.

  That is, when the oil pressure decreases with respect to the oil pressure Po, air bubbles are mixed into the oil. Therefore, when the oil temperature sensor 42 detects an arbitrary oil temperature, the ECU 44 detects this arbitrary oil temperature. Then, the oil pressure Pi is estimated from the actual measured values of the engine speed sensor 43, and the bubble ratio is estimated from the difference between the estimated oil pressure Pi and the oil pressure Po having a normal bubble ratio. The ROM 46 stores a bubble rate determination map 54 corresponding to each oil temperature. In this case, the ROM 46, the hydraulic pressure sensor 41, the oil temperature sensor 42, and the engine speed sensor 43 constitute a bubble rate acquisition means.

  In addition, although the control apparatus 4 of the internal combustion engine of this Embodiment demonstrated the example applied to the internal combustion engine for vehicles, it is applicable if an internal combustion engine is used as a power source, for example, what is called a hybrid vehicle, The present invention can be applied not only to an internal combustion engine mounted on a motorcycle or the like but also to an internal combustion engine mounted on a vehicle other than a vehicle such as a ship or a construction machine.

  As described above, the control device for an internal combustion engine according to the present invention enables the second rotating body to be held in the first rotating body at an early stage based on the bubble ratio and oil pressure mixed in the oil. Thus, the second rotating body can be prevented from fluttering and drivability can be prevented from deteriorating, and the variable valve timing mechanism can be provided when the hydraulic pressure supplied to the variable valve timing mechanism is abnormal. This is useful as a control device for an internal combustion engine that is to be protected.

2 Engine (Internal combustion engine)
4 Control device 6 Crankshaft (output shaft)
13 Oil pump 20 Intake camshaft (camshaft)
21 Exhaust camshaft 22 VVT (Variable valve timing mechanism)
31 Housing (first rotating body)
32 Vane body (second rotating body)
33 Advance-side hydraulic chamber 34 Delay-side hydraulic chamber 35 Lock pin (holding mechanism)
36 Lock hole (holding mechanism)
38 OCV (oil supply member)
41 Oil pressure sensor (oil pressure detection means, bubble rate acquisition means)
42 Oil temperature sensor (bubble ratio acquisition means)
43 Engine speed sensor (bubble rate acquisition means)
44 ECU (control means)
46 ROM (bubble rate acquisition means)
51 Warning lamp (Warning means)

Claims (4)

An advance-side hydraulic pressure that is rotatably accommodated in a first rotating body that is connected to the output shaft of the internal combustion engine and that is partitioned by the second rotating body. An internal combustion engine provided with a variable valve timing mechanism that variably controls the relative rotational phase between the camshaft and the output shaft by selectively supplying hydraulic pressure to the chamber and the retard side hydraulic chamber. An engine control device,
A first hydraulic pressure determination value and a second hydraulic pressure determination value that increases in accordance with an increase in the bubble ratio mixed in the oil on a higher hydraulic pressure side than the first hydraulic pressure determination value are set, respectively .
When the hydraulic pressure supplied to the valve timing variable mechanism is determined to be less than the first hydraulic pressure determination value by the first determination using the first hydraulic pressure determination value, the hydraulic pressure abnormality of the valve timing variable mechanism And holding control for restricting the second rotating body from rotating with respect to the first rotating body is performed,
When the hydraulic pressure supplied to the variable valve timing mechanism is determined by the first determination to be greater than or equal to the first hydraulic pressure determination value, the hydraulic pressure is determined by the second determination using the second hydraulic pressure determination value. A normal hydraulic pressure region of the valve timing variable mechanism is determined on the condition that it is determined to be equal to or greater than the second hydraulic pressure determination value, and is determined to be less than the second hydraulic pressure determination value by the second determination. control apparatus for an internal combustion engine, wherein Rukoto the holding control is performed to Taki. An oil supply member that selectively supplies oil discharged from an oil pump to the advance side hydraulic chamber and the retard side hydraulic chamber;
The valve timing variable mechanism is a holding mechanism that fixes the second rotating body to the first rotating body when the second rotating body rotates to a predetermined position with respect to the first rotating body. Have
By the oil supply member, by the vane body hydraulic pressure supplied to the advance side hydraulic chamber and the retarding hydraulic chamber so as to rotate in the predetermined position is adjusted, the holding control is carried out The control apparatus for an internal combustion engine according to claim 1. Wherein comprising a hydraulic detecting means for detecting said hydraulic pressure supplied to the variable valve timing mechanism, and a bubble rate acquisition means for acquiring the cell ratio to be mixed into the oil,
The control apparatus for an internal combustion engine according to claim 1 or 2, wherein the holding control is performed based on information from the oil pressure detection means and the bubble rate acquisition means. Control means for performing the holding control and warning means for giving a warning based on an abnormality signal, the control means, wherein the hydraulic pressure supplied to the valve timing variable mechanism is less than the first hydraulic pressure determination value The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the abnormal signal is output to the warning means on the condition of

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