JP2000345869A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely converge the hunting condition of a rotation phase in a vane type valve timing control vecice, for continuously controlling the rotation phase of a cam shaft relative to a crankshaft. SOLUTION: In this control device, the target of a rotation phase is changed to the maximum spark-delay and the maximum spark-advance, with a given load and rotation region or a deceleration condition as an approval condition (S5-S7), when an amplitude of a rotation has a given value or more (S4), to discharge oil in spark-advance and spark-delay side coil pressure chambers (S8-S11). Consequently air sucked into both the chambers by cam torque can be discharged together with the oil to converge hunting due to mixing the air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for an internal combustion engine, and more particularly, to a valve timing control device having a configuration in which the rotational phase of a camshaft with respect to a crankshaft is continuously variably controlled by hydraulic control.

[0002]

2. Description of the Related Art Conventionally, as a valve timing control device having such a configuration, there has been a vane type valve timing control device as disclosed in Japanese Patent Application Laid-Open No. H10-14022.

In this apparatus, a concave portion is formed in an inner peripheral surface of a cylindrical housing fixed to a cam sprocket, and a wing portion (vane) of an impeller fixed to a camshaft is accommodated in the concave portion. The camshaft is configured to be rotatable relative to the cam sprocket within a range in which the wing can move within the recess.

The wings supply and discharge oil relatively to a pair of hydraulic chambers formed by partitioning the recess in front and rear in the rotation direction, so that the wings are positioned at an intermediate position of the recess. And the rotary phase is continuously variable controlled.When the hydraulic pressure of the pair of hydraulic chambers is adjusted to the hydraulic pressure at which the target rotational phase is obtained, the hydraulic passage is closed by a valve. It was configured to stop oil supply and drainage.

[0005]

On the camshaft, positive and negative rotational torques (hereinafter, referred to as cam torques) are alternately generated by a valve spring for urging the intake and exhaust valves in the closing direction, thereby forming a hydraulic passage. When the supply and discharge of oil are stopped by closing the valve, the hydraulic pressure in the hydraulic chamber on the side to which the positive cam torque is applied rises. And
If oil leakage occurs due to an increase in oil pressure due to the cam torque, when the sign of the cam torque is reversed, air is sucked in from the place where the oil leak has occurred, and the air mixes with the oil in the sealed hydraulic path. When the cam torque is applied in a state where the air is mixed, the compression ratio of the air is larger than that of the oil, so that when the positive cam torque is applied, the rotation phase is more greatly displaced. There is a possibility that hunting of the rotation phase that cannot be converged by the feedback control may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in a valve timing control apparatus for an internal combustion engine having a structure in which the rotational phase of a camshaft with respect to a crankshaft is continuously variably controlled by hydraulic control, a cam torque having a rotational phase It is an object of the present invention to ensure that the hunting by the convergence can be converged.

[0007]

According to the first aspect of the present invention, the rotational phase of the camshaft with respect to the crankshaft is continuously and variably controlled by hydraulic control. In the valve timing control device for an internal combustion engine configured to selectively control the supply and discharge of the oil, the oil in the hydraulic chamber is forcibly circulated when the amplitude of the rotation phase is detected to be equal to or greater than a predetermined value. did.

According to this configuration, when the rotation phase fluctuates at a predetermined amplitude or more, it is estimated that large vibrations are generated due to the mixing of air into the hydraulic chamber, and oil in the hydraulic chamber at that time is estimated. The air is discharged by forcibly circulating the air regardless of the target rotation phase.

According to the second aspect of the present invention, the rotational phase of the camshaft with respect to the crankshaft is continuously and variably controlled by hydraulic control, and the supply and discharge of oil in the hydraulic chamber controlled by the hydraulic pressure is selectively performed. In the valve timing control device for an internal combustion engine having a control structure, the forced circulation of the oil in the hydraulic chamber is periodically performed under a predetermined hydraulic control condition.

[0010] According to this configuration, the forced circulation of the oil is periodically performed under the hydraulic control condition in which the air is mixed into the hydraulic chamber and the rotation phase is likely to fluctuate with a large amplitude. To avoid being left unattended.

According to a third aspect of the present invention, the predetermined hydraulic pressure control condition includes at least one of a temperature of the hydraulic oil at a predetermined temperature or higher and a hydraulic pressure at a predetermined value or lower. According to such a configuration, when the temperature of the hydraulic oil is high and the viscosity of the oil is low, oil leakage is likely to occur, so that the possibility of sucking air increases, while when the hydraulic pressure is equal to or less than a predetermined value,
Even if the same air is mixed, the amplitude of the rotation phase is larger and the air is sucked more, so that the oil is forcibly circulated and the air in the hydraulic chamber is evacuated.

According to the present invention, the target value of the rotation phase is forcibly changed in a direction in which the hydraulic pressure of the hydraulic chamber is discharged, thereby forcibly circulating the oil. .

According to such a configuration, by forcibly changing the target value of the rotation phase, the oil circulation (discharge of oil from the hydraulic chamber) is performed in order to match the actual rotation phase with the value after the change. Is performed.

According to a fifth aspect of the present invention, the target value of the rotational phase is forcibly changed to at least one of a most advanced angle and a most retarded angle. According to this configuration, by setting the most advanced angle or the most retarded angle, which is the boundary of the control range of the rotation phase by the hydraulic control, to the target value, almost all the oil in the hydraulic chamber is discharged and mixed with the oil. Complete exhaust of the air.

According to a sixth aspect of the present invention, there is provided an advance side hydraulic chamber and a retard side hydraulic chamber, and after changing the target value of the rotation phase to one of the most advanced angle and the most retarded angle, The configuration is changed to the other of the most advanced angle and the most retarded angle.

According to this configuration, the target value of the rotation phase is changed to one of the most advanced angle and the most retarded angle, so that the air is discharged together with the oil from one of the advanced hydraulic chamber and the retard hydraulic chamber. Then, by changing the rotation phase target value to the other of the most advanced angle and the most retarded angle, air is discharged together with the oil from the other of the advanced hydraulic chamber and the retard hydraulic chamber.

According to the present invention, the camshaft is rotated relative to a cam sprocket to continuously variably control the rotational phase of the camshaft with respect to the crankshaft. A concave portion provided on a predetermined circumference on one side with the cam sprocket,
A vane provided on the other side of the camshaft and the cam sprocket is accommodated in the recess and partitions the recess in the front and rear directions of rotation to form an advance hydraulic chamber and a retard hydraulic chamber. The rotation phase is continuously variably controlled by supplying and discharging oil relatively to the advance-side hydraulic chamber and the retard-side hydraulic chamber.

According to this structure, a so-called vane type valve timing control device that continuously controls the rotation phase by supplying and discharging oil relatively to the pair of hydraulic chambers formed by the concave portion and the vane. In, when it is estimated that air is mixed into the hydraulic chamber or under conditions where air is easily mixed, the oil is forcibly circulated to discharge the air.

According to the invention described in claim 8, the forced circulation of the oil in the hydraulic chamber is performed only under a predetermined engine operating condition. According to this configuration, the rotational phase deviates from the original target value due to the forced circulation of the oil. Therefore, the deviation of the rotational phase due to the forced circulation of the oil for air release greatly affects the operability. When the engine is not operating, the air is vented.

According to a ninth aspect of the present invention, the predetermined engine operating condition is set to a predetermined operating region divided by an engine load and an engine rotation speed. According to this configuration, a condition in which the forced circulation of the oil for air removal does not significantly affect the operability is determined based on the engine load and the engine speed.

According to a tenth aspect of the present invention, the predetermined operating condition is set to a deceleration operation state of the engine. According to such a configuration, in the deceleration operation state, the change in the rotation phase does not greatly affect the operability, so that the forced circulation of the oil for air removal is performed in the deceleration operation state.

[0022]

According to the first aspect of the invention, when it is estimated that air enters the hydraulic chamber, the air is extracted by forcible circulation of the oil. There is an effect that the state in which the phase fluctuates can be converged early.

According to the second aspect of the present invention, it is possible to avoid leaving the air entrained state by circulating the oil periodically under conditions where air entrainment into the hydraulic chamber is likely to occur. Accordingly, there is an effect that a state in which the rotation phase fluctuates with a large amplitude due to the mixing of air can be quickly converged.

According to the third aspect of the present invention, it is possible to accurately determine a condition under which air is likely to be mixed into the hydraulic chamber, and to extract air mixed into the hydraulic chamber while avoiding unnecessary oil circulation. There is an effect that can be.

According to the fourth aspect of the present invention, the target of the rotational phase is forcibly changed, so that it is controlled to match the target after the change, and as a result, the circulation of the oil in the hydraulic chamber is accurately performed. There is an effect that it can be performed.

According to the fifth aspect of the invention, by changing the target of the rotation phase to the most retarded angle or the most advanced angle, the target of the rotation phase changes in a direction in which the oil in the hydraulic chamber is drained to the maximum. Therefore, there is an effect that the air in the hydraulic chamber can be reliably removed.

According to the sixth aspect of the present invention, in the configuration in which oil is supplied and discharged relatively to the advance-side hydraulic chamber and the retard-side hydraulic chamber to control the target rotational phase, the advance-side hydraulic chamber is controlled. There is an effect that air can be reliably removed from both the chamber and the retard side hydraulic chamber.

According to a seventh aspect of the present invention, in the so-called vane type valve timing control device, air is reliably evacuated from both the advance side hydraulic chamber and the retard side hydraulic chamber, and the rotational phase with a large amplitude is obtained. This has the effect that the fluctuation of can be surely converged.

According to the eighth aspect of the invention, there is an effect that it is possible to prevent the operability from being greatly deteriorated due to the forced circulation of oil for bleeding air from the hydraulic chamber. According to the ninth aspect of the present invention, it is possible to accurately determine a condition in which the forced circulation of the oil for bleeding the air from the hydraulic chamber does not greatly affect the operability from the load and the rotation, and to prevent the operability from deteriorating. This has the effect that air can be evacuated from the hydraulic chamber.

According to the tenth aspect, by forcibly circulating the oil in the decelerating operation state, there is an effect that the influence on the drivability can be more reliably avoided.

[0031]

Embodiments of the present invention will be described below. 1 to 6 show a mechanical portion of a valve timing control device for an internal combustion engine according to the embodiment, and show a mechanism applied to an intake valve side.

The valve timing control device shown in the figure is a cam sprocket 1 (timing sprocket) driven to rotate by a crankshaft (not shown) of an engine via a timing chain, and is rotatable relative to the cam sprocket 1. A camshaft 2 provided, a rotating member 3 fixed to an end of the camshaft 2 and rotatably housed in the cam sprocket 1, and rotating the rotating member 3 relative to the cam sprocket 1. And a lock mechanism 10 for selectively locking a relative rotation position between the cam sprocket 1 and the rotating member 3 at a predetermined position.

The cam sprocket 1 has a rotating portion 5 having teeth 5a on its outer periphery with which a timing chain (or a timing belt) meshes, and a rotating member 3 disposed in front of the rotating portion 5 so as to be rotatable. A housing 6, a disk-shaped front cover 7 serving as a lid for closing a front end opening of the housing 6, and a substantially disk disposed between the housing 6 and the rotating part 5 to close a rear end of the housing 6. The rotating part 5, the housing 6, the front cover 7, and the rear cover 8 are integrally connected by four small-diameter bolts 9 in the axial direction.

The rotating part 5 has a substantially annular shape, and each small-diameter bolt 9 is screwed at an equidistant position of about 90 ° in the circumferential direction.
One of the female screw holes 5b is formed to penetrate in the front-rear direction.
A fitting hole 11 having a stepped diameter is formed to penetrate. Further, a disc-shaped fitting groove 12 into which the rear cover 8 is fitted is formed in the front end face.

The housing 6 has a cylindrical shape in which both front and rear ends are formed with openings, and four partition walls 13 are protruded from the inner peripheral surface at 90 ° in the circumferential direction. The partition 13 has a trapezoidal cross-section, and each has a housing 6.
Are provided along the axial direction of the
And four bolt insertion holes 14 through which the small-diameter bolt 9 is inserted are formed in the base end side in the axial direction. Further, a U-shaped sealing member 15 and a leaf spring 16 for pressing the sealing member 15 inward are fitted into a holding groove 13a which is cut out along the axial direction at the center position of the inner end surface of each partition 13. Is held.

Furthermore, the front cover 7 has a relatively large diameter bolt insertion hole 17 at the center, and
Four bolt holes 18 are formed in the housing 6 at positions corresponding to the bolt insertion holes 14.

The rear cover 8 has a disk portion 8a fitted and held in the fitting groove 12 of the rotary member 5 on the rear end face, and a small-diameter annular portion 2 of the sleeve 25 at the center.
An insertion hole 8c into which 5a is inserted is formed, and four bolt holes 19 are also formed at positions corresponding to the bolt insertion holes 14.

The camshaft 2 comprises a cylinder head 2
A cam (not shown) for rotatably supporting an intake valve via a valve lifter is integrally provided at a predetermined position on the outer peripheral surface at a top end of the second end via a cam bearing. The part is provided integrally with a flange part 24.

The rotating member 3 is fixed to the front end of the camshaft 2 by a fixing bolt 26 inserted from the axial direction through the sleeve 25 whose front and rear portions are fitted into the flange portion 24 and the fitting hole 11, respectively. An annular base 27 having a bolt insertion hole 27a through which the fixing bolt 26 is inserted at the center, and four vanes 28a, 28b, 2 integrally provided at a position at 90 ° in the circumferential direction of the outer peripheral surface of the base 27.
8c and 28d.

The first to fourth vanes 28a to 28d are:
Each cross section has a substantially inverted trapezoidal shape, and is disposed in a concave portion between the partition portions 13, and separates the concave portion before and after in the rotation direction, between both sides of the vanes 28 a to 28 d and both side surfaces of each partition portion 13. In addition, an advance hydraulic chamber 32 and a retard hydraulic chamber 33 are configured. Further, the inner peripheral surface 6 of the housing 6 is inserted into a holding groove 29 which is notched in the axial direction at the center of the outer peripheral surface of each of the vanes 28a to 28d.
and a U-shaped seal member 30 slidably contacting the
The leaf springs 31 that press 0 outward are respectively fitted and held.

The lock mechanism 10 includes an engagement groove 20 formed at a predetermined position on the outer peripheral side of the fitting groove 12 of the rotating portion 5,
An engagement hole 21 formed through a predetermined position of the rear cover 8 corresponding to the engagement groove 20 and having a tapered inner peripheral surface;
A sliding hole 35 penetratingly formed along the inner axial direction at a substantially central position of the one vane 28 corresponding to the engagement hole 21.
A lock pin 34 slidably provided in the slide hole 35 of the one vane 28; and a coil spring 3 which is a spring member elastically mounted on the rear end side of the lock pin 34.
9 and a pressure receiving chamber 40 formed between the lock pin 34 and the sliding hole 35.

The lock pin 34 is formed with a middle-diameter main body 34a on the center side, an engaging portion 34b formed in a tapered conical shape on the distal end side of the main body 34a, and a rear end side of the main body 34a. And a stopper portion 34c having a large-diameter stepped portion, and is engaged by the spring force of the coil spring 39 elastically mounted between the bottom surface of the internal concave groove 34d of the stopper portion 34c and the inner end surface of the front cover 7. In the pressure receiving chamber 40 formed between the main body 34a and the stopper 34c and between the main body 34a and the stopper 34c and between the main body 34a and the inner peripheral surface of the sliding hole 35. It slides in the direction of coming out of the engagement hole 21 by the hydraulic pressure.
The pressure receiving chamber 40 communicates with the retard side hydraulic chamber 33 through a through hole 36 formed in a side portion of the vane 28. The engaging portion 34b of the lock pin 34 engages with the engaging hole 21 at the rotation position on the maximum retard side of the rotating member 3.

The hydraulic circuit 4 comprises a first hydraulic passage 41 for supplying and discharging hydraulic pressure to and from the advance hydraulic chamber 32, and a second hydraulic passage 42 for supplying and discharging hydraulic pressure to the retard hydraulic chamber 33. The two hydraulic passages 41 and 42 have
The supply passage 43 and the drain passage 44 are connected to each other via an electromagnetic switching valve 45 for switching the passage. An oil pump 47 for pumping oil in an oil pan 46 is provided in the supply passage 43, while a downstream end of the drain passage 44 communicates with the oil pan 46.

The first hydraulic passage 41 has a first hydraulic passage 41 formed inside the cylinder head 22 and inside the axis of the camshaft 2.
A passage portion 41a, a first oil passage 41b branched and formed in the head portion 26a through the axial direction inside the fixing bolt 26 and communicating with the first passage portion 41a, a small-diameter outer peripheral surface of the head portion 26a, and a rotating member An oil chamber 41c formed between the inner peripheral surface of the bolt insertion hole 27a provided in the base 27 of the third rotating member 3 and communicating with the first oil passage 41b; It is composed of a chamber 41c and four branch passages 41d communicating with each advance-side hydraulic chamber 32.

On the other hand, the second hydraulic passage 42 is formed in the cylinder head 22 and on one side inside the camshaft 2 and a second passage portion 42a formed inside the sleeve 25 in a substantially L-shape. A second oil passage 42b communicating with the second passage portion 42a, and four oil passage grooves 42 formed at the outer peripheral side edge of the fitting hole 11 of the rotating member 5 and communicating with the second oil passage 42b.
c and four oil holes 42d formed at about 90 ° in the circumferential direction of the rear cover 8 and communicating each oil passage groove 42c and the retard side hydraulic chamber 33.

The electromagnetic switching valve 45 controls the relative switching between the hydraulic passages 41 and 42, the supply passage 43, and the drain passages 44a and 44b by an internal spool valve body. The switching operation is performed by the control signal of (1).

More specifically, as shown in FIGS. 4 to 6, a cylindrical valve body 51 inserted and fixed in a holding hole 50 of a cylinder block 49 and a valve hole 52 in the valve body 51 are slid. The spool valve 53 is provided movably and switches a flow path, and includes a proportional solenoid type electromagnetic actuator 54 for operating the spool valve 53.

The valve body 51 has a supply port 55 penetratingly formed at a substantially central position of the peripheral wall and communicating the downstream end of the supply passage 43 with the valve hole 52. First and second hydraulic passages 41 and 42
A first port 56 and a second port 57 that communicate the other end of the valve and the valve hole 52 are formed through each. The two drain passages 44a, 44b and the valve hole 5 are provided at both ends of the peripheral wall.
Third and fourth ports 58 and 59 communicating with the second port 2 are formed through.

The spool valve element 53 has a substantially cylindrical first valve part 60 for opening and closing the supply port 55 at the center of the small-diameter shaft part, and has third and fourth ports 58 and 5 at both ends.
9 has a substantially cylindrical second and third valve portions 61 and 62 for opening and closing the valve 9. Further, the spool valve element 53 is connected to the front end shaft 5.
A conical valve spring 63 elastically mounted between an umbrella portion 53b provided on one end edge of the valve 3a and a spring seat 51a provided on an inner peripheral wall on the front end side of the valve hole 52, to the right in the drawing, that is, the first valve portion 60. Urged in a direction to connect the supply port 55 with the second hydraulic passage 42.

The electromagnetic actuator 54 includes a core 6
4, a moving rod 65a that includes a moving plunger 65, a coil 66, a connector 67, and the like, and that presses an umbrella portion 53b of the spool valve body 53 is fixed to an end of the moving plunger 65.

The controller 48 detects the current operation state (load, rotation) based on signals from a rotation sensor 101 for detecting the engine rotation speed and an air flow meter 102 for detecting the amount of intake air. 2, a target value of the rotational phase of the camshaft 2 with respect to the crankshaft is set, and an actual value of the rotational phase is detected based on signals from the crank angle sensor 103 and the cam sensor 104. The amount of energization to the actuator 54 is controlled based on a duty control signal on which a dither signal is superimposed.

For example, when the controller 48 outputs a control signal (OFF signal) having a duty ratio of 0% to the electromagnetic actuator 54, the spool valve body 53 is moved to the position shown in FIG. Go to Accordingly, the first valve portion 60 opens the open end 55a of the supply port 55 to communicate with the second port 57, and at the same time, the second valve portion 61 opens the open end of the third port 58, and the fourth The valve part 62 closes the fourth port 59.
Therefore, the hydraulic oil pumped from the oil pump 47 is
The hydraulic fluid is supplied to the retard hydraulic chamber 33 through the supply port 55, the valve hole 52, the second port 57, and the second hydraulic passage 42, and the hydraulic oil in the advance hydraulic chamber 32 is supplied to the first hydraulic passage 4.
The oil is discharged from the first drain passage 44a into the oil pan 46 through the first port 56, the valve hole 52, and the third port 58.

Accordingly, the internal pressure of the retard side hydraulic chamber 33 becomes high and the internal pressure of the advance side hydraulic chamber 32 becomes low, so that the rotating member 3 rotates in one direction at maximum through the vanes 28a to 28b. As a result, the cam sprocket 1 and the camshaft 2 relatively rotate to one side to change the phase. As a result, the opening timing of the intake valve is delayed, and the overlap with the exhaust valve is reduced.

On the other hand, when a control signal (ON signal) having a duty ratio of 100% is output from the controller 48 to the electromagnetic actuator 54, the spool valve body 53 moves in the leftward direction against the spring force of the valve spring 63 as shown in FIG. To the maximum, the third valve portion 61 closes the third port 58, and at the same time, the fourth valve portion 62 opens the fourth port 59,
The first valve section 60 makes the supply port 55 communicate with the first port 56. Therefore, the hydraulic oil is supplied to the advance hydraulic chamber 32 through the supply port 55, the first port 56, and the first hydraulic passage 41, and the hydraulic oil in the retard hydraulic chamber 33 is supplied to the second hydraulic chamber 32. Hydraulic passage 42, second port 57, fourth port 5
9. The oil is discharged to the oil pan 46 through the second drain passage 44b, and the pressure in the retard-side hydraulic chamber 33 becomes low.

For this reason, the rotating member 3 includes the vanes 28a to 28a.
Rotate in the other direction to the maximum through 28d,
The cam sprocket 1 and the camshaft 2 relatively rotate to the other side to change the phase. As a result, the opening timing of the intake valve is advanced (advanced), and the overlap with the exhaust valve is increased.

The controller 48 is configured such that the first valve portion 60 closes the supply port 55, the third valve portion 61 closes the third port 58, and the fourth valve portion 62 closes the fourth port 5.
The base duty ratio BASEDTY (for example, 50%) is used as the duty ratio at which the position of the cam sprocket 9 is closed, and the relative rotation between the cam sprocket 1 and the camshaft 2 detected based on signals from the crank angle sensor 103 and the cam sensor 104. A feedback correction amount P for matching a moving position (rotational phase) with a target value (target advance value) of the relative rotational position (rotational phase) set according to the driving state.
IDDTY is set by a proportional / integral / differential (PID) operation, and the addition result of the base duty ratio BASEDTY and feedback correction amount PIDDTY is set as a final duty ratio VTCTY, and the duty ratio VTC is set.
A DTY control signal is output to the electromagnetic actuator 54.

That is, when it is necessary to change the relative rotation position (rotation phase) in the retard direction, the duty ratio is reduced by the feedback correction amount PIDDTY, and the hydraulic oil pressure-fed from the oil pump 47 is reduced. While being supplied to the retard side hydraulic chamber 33, the hydraulic oil in the advance side hydraulic chamber 32 is discharged into the oil pan 46, and conversely, the relative rotation position (rotation phase) is advanced. When it is necessary to change in the direction, the feedback correction P
The duty ratio is increased by the IDDTY, the hydraulic oil is supplied into the advance side hydraulic chamber 32 and the retard side hydraulic chamber 3
3 is discharged to the oil pan 46. When the relative rotation position (rotation phase) is maintained in the current state, the feedback correction PI
When the absolute value of DDTY decreases, the duty ratio is controlled to return to a duty ratio near the base duty ratio.
5. By closing the third port 58 and the fourth port 59 (stopping the supply and discharge of the hydraulic pressure), the internal pressure of each of the hydraulic chambers 32 and 33 is controlled.

Further, the controller 48 circulates the oil in each of the hydraulic chambers 32, 33 by forcibly changing the rotation phase so as to converge the occurrence of hunting due to the mixing of air into the hydraulic chambers 32, 33. Control to evacuate the air, and the state of such control is shown in FIG.
This will be described according to the flowchart of FIG.

At S1, the actual rotational phase (advance angle value) is
It is detected based on signals from the crank angle sensor 103 and the cam sensor 104. In S2, the maximum and minimum values of the rotation phase detected in S1 are obtained.

In S3, the amplitude of the rotation phase is calculated as the difference between the maximum value and the minimum value. Instead of calculating the deviation between the maximum value and the minimum value, a configuration may be used in which the standard deviation of the rotation phase and the like are calculated.

In S4, it is determined whether or not the detection result of the amplitude exceeds a predetermined value. When it is determined in S4 that the detection result of the amplitude exceeds a predetermined value, air is sucked into the hydraulic chambers 32 and 33 by the action of the cam torque, and the rotation phase fluctuates with a large amplitude due to the mixing of the air. It is presumed that it has been performed, and the process proceeds to S5 and thereafter.

Steps S5 to S7 are for judging permission conditions for controlling the removal of air mixed in the hydraulic chambers 32 and 33. In step S5, it is determined whether or not the engine speed is equal to or higher than a predetermined speed. If it is determined that the speed is equal to or higher than the predetermined speed, the process proceeds to S6.

At S6, it is determined whether or not the engine load is equal to or more than a predetermined value based on the intake air amount of the engine. When the engine speed is equal to or higher than the predetermined speed and the engine load is equal to or higher than the predetermined value, it is determined that the drivability is not significantly affected even if the target rotation phase is forcibly changed as described later. , S8 and subsequent steps.

On the other hand, when it is determined that the condition of the engine speed or the engine load is not satisfied, the process proceeds to S7, where the engine is in a deceleration operation state (preferably, a deceleration fuel cut state).
Is determined.

Even if the condition of the engine speed or the engine load is not satisfied, if it is determined that the engine is in the deceleration operation state, even if the target rotation phase described later is forcibly changed, It is determined that the driving performance is not greatly affected, and the process proceeds to S8 and subsequent steps. That is, when the detection result of the amplitude exceeds the predetermined value and the engine speed and the engine load are within the predetermined range or when the engine is in the deceleration operation state, the process proceeds to S8 and thereafter.

In S8, the target rotational phase is forcibly changed to the most retarded angle. By forcibly setting the target rotational phase to the most retarded angle, oil is supplied to the retarded hydraulic chamber 33 in order to increase the hydraulic pressure on the retarded hydraulic chamber 33 side, while the advanced hydraulic chamber 32 is supplied.
Then, the oil is drained and circulated, and the air mixed with the oil in the advance side hydraulic chamber 32 is discharged together with the oil.

In step S9, the elapse of the predetermined delay time is determined, the target rotational phase is forcibly changed to the most retarded angle, and then the time necessary and sufficient to discharge the oil from the advance hydraulic chamber 32 elapses. It is determined whether or not it has been performed. Instead of determining whether the predetermined delay time has elapsed, it may be determined whether or not the actual rotational phase has reached near the most retarded angle.

If it is determined in S9 that the predetermined delay time has elapsed, the process proceeds to S10, in which the target rotational phase is forcibly changed to the most advanced angle. By forcibly setting the target rotation phase to the most advanced angle, oil is supplied to the advanced hydraulic chamber 32 to increase the oil pressure on the advanced hydraulic chamber 32 side, while the oil is supplied from the retard hydraulic chamber 33. The oil is drained and circulated, and the air mixed with the oil in the retard hydraulic chamber 33 is discharged together with the oil.

In S11, it is determined whether a predetermined delay time has elapsed, and the target rotation phase is forcibly changed to the most advanced angle.
It is determined whether or not a time sufficient and sufficient to discharge the oil from the retard side hydraulic chamber 33 has elapsed. Here, instead of determining whether the predetermined delay time has elapsed, it may be determined whether or not the actual rotational phase has reached near the most advanced angle.

When it is determined in step S11 that the predetermined delay time has elapsed, the target rotation phase is returned to the normal value, and the routine ends. As described above, when the amplitude of the rotation phase exceeds the allowable level and increases, the target rotation phase is forcibly swung to the most retarded angle and the most advanced angle to forcibly circulate the hydraulic pressure in the hydraulic chambers 32 and 33. Thus, the air mixed in the hydraulic chambers 32, 33 can be discharged, and the fluctuation of the rotation phase caused by the mixing of the air can be converged.

Further, the air is discharged by changing the target rotation phase only when the change in the rotation phase is an engine operating condition that does not greatly affect the drivability, so that the influence on the drivability is minimized. Can be suppressed.

FIG. 8 is a flow chart showing a second embodiment of the control for circulating the oil in each of the hydraulic chambers 32 and 33 to remove air by forcibly changing the rotation phase. In S21, it is determined whether or not the engine coolant temperature detected by the coolant temperature sensor 105 is equal to or higher than a predetermined temperature. The cooling water temperature is determined as a parameter correlated with the temperature of the hydraulic oil. When the cooling water temperature is equal to or higher than a predetermined temperature, it is estimated that the temperature of the hydraulic oil is in a predetermined high temperature state. It should be noted that the temperature of the hydraulic oil may be directly detected.

When the cooling water temperature of the engine is equal to or higher than the predetermined temperature, the program proceeds to S22, in which it is determined whether or not the supply pressure of the working oil by the oil pump 47 is equal to or lower than the predetermined pressure.
7 is determined based on the detection result of the hydraulic pressure sensor 106 provided on the downstream side of the control unit 7.

When the oil pump 47 is driven by a crankshaft, the engine speed is a parameter correlated with the supply pressure of the hydraulic oil. May be configured to determine whether the supply pressure of the hydraulic oil is greater than or equal to a predetermined value set individually.

When it is determined in S22 that the hydraulic pressure is equal to or lower than the predetermined pressure, it is determined that there is a high possibility that the rotational phase greatly changes, and the process proceeds to S23 and thereafter. When the temperature of the cooling water of the engine is equal to or higher than the predetermined temperature and the temperature of the hydraulic oil is estimated to be equal to or higher than the predetermined temperature, the viscosity of the hydraulic oil is low, and oil leakage easily occurs when a cam torque is applied. Therefore, air is easily sucked into the hydraulic chamber. Further, when the hydraulic pressure is low, the rotation phase fluctuates with a larger amplitude even when the same cam torque is applied than when the hydraulic pressure is high, and the amount of air suction increases.

Therefore, after S23, the target rotational phase is forcibly shifted to the most retarded angle and the most advanced angle under predetermined engine operating conditions, as in the first embodiment shown in FIG. The process of forcibly circulating the hydraulic pressure of the chambers 32 and 33 is periodically performed.

In S23, it is determined whether or not the value of a timer for measuring the execution interval of the forced circulation control is equal to or greater than a predetermined value.
Proceed to 2 to count up the timer.

The timer is reset to 0 in S33 when the condition of the oil temperature and the oil pressure is not satisfied and the process does not proceed to S23. If it is determined in S23 that the timer value is equal to or greater than the predetermined value, the process proceeds to S24. The processing after S24 is the same as S5 to S11 in the flowchart of FIG. 7 described above. In S24 to S26, the load, which is the operating condition under which the rotational phase can be forcibly changed to the most retarded angle and the most advanced angle, is permitted. -It is determined whether it is in the rotation region or in the deceleration operation state.

When the vehicle is in the predetermined load / rotation region or in the deceleration operation state, the process proceeds to S27 to S30, and the target of the rotation phase is forcibly set to the most retarded state. After the delay time is continued, the target of the rotation phase is forcibly set to the most advanced angle and the process is continued for the predetermined delay time.
Forcibly circulating the hydraulic pressures of the hydraulic chambers 2 and 33 to discharge the air mixed in the hydraulic chambers 32 and 33, and to converge the fluctuation of the rotation phase caused by the mixing of the air.

In S31, the timer is reset to 0 so that the rotation phase is not forcibly changed until the value of the timer is counted up to the predetermined value again.

In the above embodiment, the valve timing control device is a so-called vane type. However, the hydraulic pressure in the hydraulic chamber acts in the axial direction of the camshaft, and the hydraulic pressure in the axial direction is converted into a force in the rotational direction. Valve timing control having a mechanism for controlling the hydraulic pressure in the hydraulic chamber to a pressure corresponding to a target advance value by supplying and discharging the hydraulic pressure to and from the hydraulic chamber to continuously change the rotation phase In the device, in the same manner as in the above embodiment, when the fluctuation of the rotation phase becomes large, or under the condition that a large rotation fluctuation can occur, the oil in the hydraulic chamber is circulated by changing the target value of the rotation phase. You may do it.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a valve timing control mechanism according to an embodiment.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is an exploded perspective view of the valve timing control mechanism.

FIG. 4 is a longitudinal sectional view showing an electromagnetic switching valve in the valve timing control mechanism.

FIG. 5 is a longitudinal sectional view showing an electromagnetic switching valve in the valve timing control mechanism.

FIG. 6 is a longitudinal sectional view showing an electromagnetic switching valve in the valve timing control mechanism.

FIG. 7 is a flowchart showing a first embodiment of control of the valve timing control mechanism.

FIG. 8 is a flowchart showing a second embodiment of the control of the valve timing control mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cam sprocket 2 ... Camshaft 3 ... Rotating member 4 ... Hydraulic circuit 6 ... Housing 7 ... Front cover 13 ... Partition wall 28a-28d ... Vane 32 ... Advance side hydraulic chamber 33 ... Retard side hydraulic chamber 45 ... Electromagnetic switching valve 47 oil pump 51 valve body 52 valve hole 53 spool valve 55 supply port 55a open end 56 first port 57 second port 60 first valve 101 rotation sensor 102 air flow meter 103 ... Crank angle sensor 104 ... Cam sensor 105 ... Water temperature sensor 106 ... Hydraulic sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G016 AA19 DA06 DA22 GA03 3G092 AA11 DA01 DA02 DA09 DF04 DG05 DG09 EA03 EA04 EA09 EA11 EA16 EA17 EA22 EA28 EA29 EC08 FA05 GA13 HA11Z HA13X HA13Z HE01Z HE03Z HE08

Claims (10)

[Claims] An internal combustion engine configured to continuously and variably control the rotational phase of a camshaft with respect to a crankshaft by hydraulic control, and selectively controlling supply and discharge of oil in a hydraulic chamber controlled by the hydraulic pressure. The valve timing control device for an internal combustion engine, wherein when the amplitude of the rotation phase is detected to be equal to or greater than a predetermined value, the oil in the hydraulic chamber is forcibly circulated. . 2. An internal combustion engine in which the rotational phase of a camshaft with respect to a crankshaft is continuously and variably controlled by hydraulic control, and wherein the supply and discharge of oil in a hydraulic chamber controlled by the hydraulic pressure are selectively controlled. The valve timing control device for an internal combustion engine according to claim 1, wherein forced circulation of oil in said hydraulic chamber is periodically performed under predetermined hydraulic control conditions. 3. The valve timing control of an internal combustion engine according to claim 2, wherein the predetermined hydraulic pressure control condition includes at least one of a temperature of a hydraulic oil equal to or higher than a predetermined temperature and a hydraulic pressure equal to or lower than a predetermined value. apparatus. 4. A forced circulation of oil is performed by forcibly changing the target value of the rotation phase in a direction in which the hydraulic pressure of the hydraulic chamber is discharged. 3
The valve timing control device for an internal combustion engine according to any one of the above. 5. The valve timing control device for an internal combustion engine according to claim 4, wherein the target value of the rotation phase is forcibly changed to at least one of a most advanced angle and a most retarded angle. 6. An advanced hydraulic pressure chamber and a retard hydraulic pressure chamber, wherein the target value of the rotation phase is changed to one of a most advanced angle and a most retarded angle, and then the most advanced angle and the most retarded angle are set. 6. The valve timing control device for an internal combustion engine according to claim 5, wherein the value is changed to the other of the angle and the angle. 7. A structure in which the camshaft is rotated relative to a cam sprocket to continuously and variably control the rotational phase of the camshaft with respect to a crankshaft, wherein one side of the camshaft and the cam sprocket is provided. A recess provided on a predetermined circumference of the camshaft and the cam sprocket, the recess is provided in the other side of the camshaft and the cam sprocket, and is accommodated in the recess. A vane forming an angle-side hydraulic chamber, and by supplying and discharging oil relatively to the advance-side hydraulic chamber and the retard-side hydraulic chamber, the rotational phase is continuously variably controlled. 7. The valve timing control device for an internal combustion engine according to claim 6, wherein: 8. The internal combustion engine according to claim 1, wherein the forced circulation of the oil in the hydraulic chamber is performed only under predetermined engine operating conditions. Valve timing control device. 9. The valve timing control apparatus for an internal combustion engine according to claim 8, wherein said predetermined engine operation condition is a predetermined operation region divided by an engine load and an engine rotation speed. 10. The valve timing control apparatus for an internal combustion engine according to claim 8, wherein the predetermined operating condition is a deceleration operation state of the engine.