JP2002161766A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve timing control device for an internal combustion engine capable of suppressing, to the utmost, the deterioration of starting and emission at an engine start afterward even if not locked by a locking mechanism. SOLUTION: This valve timing control device is provided with the locking mechanism for locking the relative rotation phase of a suction camshaft at an intermediate phase θ. In an electronic control device, the relative rotation phase of the suction camshaft is advanced in a prescribed phase or more for a prescribed period after the turn-off operation of an IG switch, and it is judged whether or not the maximum value θmax of the relative rotation phase in the above prescribed period exists at a more advanced side than the intermediate phase θ (step S13). In the starting of the internal combustion engine, when the maximum value θmax exists at a more delayed side than the phase θ (step S17: NO), it is inhibited to supply a hydraulic fluid to an advancing side pressure chamber for holding a locking state by the locking mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a valve timing control device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, an internal combustion engine such as an in-vehicle engine is provided with a variable valve timing mechanism for appropriately changing the valve timing of the engine in order to improve the output and the emission. (For example,
See JP-A-11-229828). Such a variable valve timing mechanism includes, for example, a movable member connected to a camshaft of an internal combustion engine, and an advance side pressure chamber and a retard side pressure chamber provided so as to sandwich the movable member. Then, the relative rotation phase of the camshaft with respect to the crankshaft of the engine is changed to the advance side or the retard side by selectively supplying hydraulic oil to the pressure chambers and moving the movable member by hydraulic pressure. By changing the relative rotation phase of the camshaft in this manner, the valve timing of the engine valve in the engine is changed.

[0003] By the way, when the internal combustion engine is started to start, the operating oil may be in a state of being released from the pressure chamber. Since a high oil pressure does not act, the relative rotational phase (valve timing) of the camshaft may be in the most retarded state due to the reaction force accompanying the opening and closing drive of the engine valve. Therefore, in order to improve the startability of the internal combustion engine, when the valve timing of the engine valve becomes the most retarded state, a valve timing suitable for starting the engine (hereinafter referred to as start timing) is obtained. It is necessary to set the control range of the valve timing.

However, if the control range of the valve timing is set so as to satisfy the above requirements, the control range is narrowed, and it is difficult to optimally control the valve timing over the entire operation range of the internal combustion engine. Become. Therefore, as a technique for suppressing the reduction of the control range of the valve timing while optimizing the valve timing at the time of starting the engine, a valve timing control device provided with a lock mechanism for fixing the relative rotation phase of the cam shaft at the time of starting the engine has been proposed. ing. In such a valve timing control device, when the engine is stopped, the relative rotation phase of the cam shaft is locked in a state advanced by a predetermined amount from the most retarded state by the lock mechanism, and when the engine is started thereafter, the operation supplied from the pressure chamber is performed. The locked state of the lock mechanism is maintained based on the oil pressure of the oil. As a result, when the engine is started, the valve timing can be maintained at the start timing, and the startability of the engine can be improved.

[0005]

The provision of the lock mechanism as described above makes it possible to ensure good engine startability without limiting the control range of the valve timing.

However, if the internal combustion engine is started for some reason without being locked by the lock mechanism, the following disadvantages cannot be ignored.
For example, when the engine is stopped and restarted immediately thereafter, since sufficient hydraulic oil remains in the pressure chamber, hydraulic oil for maintaining the locked state of the lock mechanism is supplied to the pressure chamber. Then, the oil pressure in the pressure chamber immediately rises. As a result, a situation may occur in which the relative rotational phase of the camshaft is significantly deviated from the phase to be locked by the lock mechanism due to the raised hydraulic pressure in the pressure chamber.

[0007] For example, when the engine is restarted after a long time has elapsed since the engine was stopped, almost no hydraulic oil remains in the pressure chamber, and even if hydraulic oil for holding a lock is supplied, the same problem occurs. Since the oil pressure in the pressure chamber does not rise immediately, the relative rotation phase of the camshaft is changed to the retard side by the reaction force accompanying the opening and closing drive of the engine valve, and deviates from the phase to be locked by the lock mechanism, the most retarded state Becomes

As described above, in the valve timing control device having the lock mechanism, when the engine is started without being locked by the lock mechanism, the valve timing is greatly shifted from the timing suitable for starting the engine. As a result, the deterioration of starting performance and emission was unavoidable.

The present invention has been made in view of such a conventional situation, and its object is to prevent deterioration of the startability and emission at the time of subsequent engine start even if the lock by the lock mechanism is not performed when the engine is stopped. It is an object of the present invention to provide a valve timing control device for an internal combustion engine that can minimize the control.

[0010]

The means for achieving the above object and the effects thereof will be described below. The invention according to claim 1 is a valve timing variable mechanism that changes a relative rotation phase of a camshaft with respect to a crankshaft of an internal combustion engine based on fluid pressures of an advance side pressure chamber and a retard side pressure chamber, and the camshaft. The relative rotational phase is locked to an intermediate phase between the most retarded state and the most advanced state, and the locked state is established based on the fluid pressure of at least one of the advance side pressure chamber and the retard side pressure chamber. And a control means for controlling the fluid pressure in the one pressure chamber until a predetermined period has elapsed from the start of the engine in order to maintain the locked state of the lock means. Determining means for determining that the relative rotational phase of the camshaft is not locked by the locking means; and determining that the relative rotational phase is not locked by the determining means. Stage by the subject matter in that it comprises a prohibiting means for prohibiting the control fluid pressure of the one pressure chamber by said control means on the basis that it is determined that it is not locked.

In the above configuration, the fluid pressure in at least one of the two pressure chambers is controlled until a predetermined period has elapsed since the start of the engine. As a result, if the locking is performed by the locking means, the locked state is maintained.
However, if the lock is not performed for some reason and the fluid pressure in the one pressure chamber is controlled in that state, the relative rotation phase of the camshaft may be set to start the engine according to the fluid pressure in the same pressure chamber. There is a possibility that the phase may be changed to a phase significantly different from the appropriate phase.

In this respect, according to the above configuration, when the relative rotation phase is not locked by the locking means,
Since the fluid pressure control for maintaining such a locked state is prohibited, the relative rotation phase of the camshaft is not changed to a phase that is significantly different from the phase suitable for starting the engine, as described above. As a result, it is possible to suppress the deterioration of the startability and the emission at the time of starting the internal combustion engine.

According to a second aspect of the present invention, in the valve timing control apparatus for an internal combustion engine according to the first aspect, the determining means determines that the relative rotational phase at the time of starting the engine is more retarded than the intermediate phase. The gist of the present invention is to judge that the lock is not performed by the lock means based on the phase.

[0014] The invention according to claim 3 provides the invention according to claim 1.
In the valve timing control device for an internal combustion engine described in the above, the control means controls the fluid pressures of the two pressure chambers for a predetermined period when the engine is stopped so that the relative rotational phase is a phase advanced from the intermediate phase. The determination means locks the lock means based on the fact that the relative rotation phase does not reach the intermediate phase during the predetermined period in which the control means controls the fluid pressures of the two pressure chambers. The gist is to judge that they have not.

If the relative rotational phase of the camshaft coincides with the intermediate phase at the time of starting the engine, it means that the lock has been achieved by the lock means. However, if the relative rotational phase of the camshaft is on the more advanced side than the intermediate phase when the engine is started, the relative rotational phase of the camshaft is changed to the retarded side due to the reaction force accompanying the opening and closing drive of the engine valve. Therefore, when the intermediate phase is reached, locking by the locking means is performed. On the other hand, when the relative rotation phase of the camshaft at the time of starting the engine is a phase that is more retarded than the intermediate phase, the locking by the locking means is not performed when the engine is started.

According to the second or third aspect of the present invention, the relative rotational phase of the camshaft at the time of starting the engine is a phase that is more retarded than the intermediate phase, or when the engine is stopped, the two pressures are reduced. Based on the fact that the relative rotational phase of the camshaft does not reach the intermediate phase during the period in which the fluid pressure in the chamber is controlled, it is determined that the locking by the locking means has not been performed. Will be able to do it.

According to a fourth aspect of the present invention, there is provided a variable valve timing mechanism for changing a relative rotation phase of a camshaft with respect to a crankshaft of an internal combustion engine based on fluid pressures of an advance pressure chamber and a retard pressure chamber. Control means for controlling the fluid pressures of the two pressure chambers to change the relative rotational phase of the camshaft to a target phase by a variable valve timing mechanism; And a lock means for locking to an intermediate phase between the valve timing control device of the internal combustion engine,
Determining means for determining that the relative rotation phase of the camshaft is not locked by the locking means,
The control means sets the target phase to the intermediate phase until a predetermined period has elapsed from the start of the engine, based on the determination means determining that the relative rotational phase is not locked by the locking means. The gist is that

According to a fifth aspect of the present invention, in the valve timing control apparatus for an internal combustion engine according to the fourth aspect, the control means determines a degree of deviation between an actual relative rotation phase of the camshaft and the target phase. The gist is that the fluid pressures of the two pressure chambers are feedback-controlled based on the pressure.

According to the configuration of the fourth or fifth aspect of the present invention, when the relative rotation phase of the camshaft is not locked by the locking means, the relative rotation phase is equal to the intermediate phase to be locked by the locking means. Thus, the fluid pressures of both pressure chambers are controlled. For this reason, it is possible to suppress the relative rotational phase from shifting to the most retarded state due to the reaction force accompanying the opening / closing drive of the engine valve and to make the relative rotational phase closer to the intermediate phase suitable for starting the engine. In this case, it is possible to suppress the deterioration of the startability and the emission at the time of starting.

When controlling the fluid pressures of the two pressure chambers so that the relative rotational phase of the camshaft becomes the target phase, the actual relative rotational phase of the camshaft and the actual relative rotational phase of the camshaft are controlled. It is preferable that the fluid pressures of both pressure chambers are feedback-controlled based on the degree of deviation from the target phase.

According to a sixth aspect of the present invention, in the valve timing control apparatus for an internal combustion engine according to the fifth aspect, the control means sets the target phase to the intermediate phase until a predetermined period has elapsed since the start of the engine. When the fluid pressures of the two pressure chambers are feedback-controlled, the gist is to set the feedback gain to be larger than the feedback gain after the lapse of the predetermined period.

According to the above arrangement, when the amount of fluid supplied to both pressure chambers cannot be sufficiently ensured, such as when starting the engine, the actual relative rotational phase of the camshaft is reduced to the intermediate phase as much as possible. You will be able to get closer as soon as possible.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a valve timing control apparatus for an internal combustion engine according to the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the cylinder block 11a of the internal combustion engine 11 has a piston 12 (FIG. 1) for each cylinder.
Is provided so as to be able to reciprocate.
The piston 12 is connected via a connecting rod 13 to a crankshaft 14 which is an output shaft of the internal combustion engine 11.

A combustion chamber 16 is provided between the piston 12 and the cylinder head 15 provided at the upper end of the cylinder block 11a. Cylinder head 15
An intake port 17 and an exhaust port 18 are formed in the combustion chamber 16 and are connected to an intake passage 19 and an exhaust passage 20, respectively. The intake port 17 and the exhaust port 18
Are provided with an intake valve 21 and an exhaust valve 22, respectively. A throttle valve (not shown) is provided in the middle of the intake passage 19, and a bypass passage (not shown) connected to the intake passage 19 on the upstream and downstream sides of the throttle valve so as to bypass the throttle valve. Is provided. An idle speed control valve (not shown) is provided in the middle of the bypass passage, and the intake air amount during idle operation is adjusted according to the opening of the valve.

An intake camshaft 23 and an exhaust camshaft 24 for opening and closing the intake valve 21 and the exhaust valve 22 are rotatably supported on the cylinder head 15. The rotational force of the crankshaft 14 is transmitted to the camshafts 23 and 24 via a chain 28 and a gear 31 (see FIG. 2). When the intake camshaft 23 rotates, the intake valve 21 is opened and closed via an intake cam (not shown).
The communication with the combustion chamber 16 is interrupted. When the exhaust camshaft 24 rotates, the exhaust valve 22 is also opened and closed via an exhaust cam (not shown), and the exhaust port 1
8 and the combustion chamber 16 are communicated and shut off.

On the other hand, at the downstream end of the intake passage 19, a fuel injection valve 25 for injecting fuel into the intake port 17 is provided. The fuel injection valve 25 injects fuel into the intake port 17 when air in the intake passage 19 is sucked into the combustion chamber 16 during an intake stroke of the internal combustion engine 11 to form a mixture of fuel and air. I do.

The combustion chamber 1 is provided in the cylinder head 15.
An ignition plug 26 for igniting the air-fuel mixture filled in the fuel cell 6 is provided. When the air-fuel mixture in the combustion chamber 16 is ignited and the air-fuel mixture burns, the combustion energy causes the piston 12 to reciprocate to rotate the crankshaft 14 and drive the internal combustion engine 11. The air-fuel mixture burned in the combustion chamber 16 is sent out to the exhaust passage 20 as exhaust by the rise of the piston 12 during the exhaust stroke of the internal combustion engine 11.

Next, a variable valve timing mechanism 30 for varying the valve timing of the intake valve 21 in the internal combustion engine 11 will be described with reference to FIG. FIG.
As shown in FIG. 5, the variable valve timing mechanism 30 includes the gear 31 and the bolt 3 on the tip end surface of the intake camshaft 23.
2 and a rotating member 33 fixed so as to be integrally rotatable. The gear 31 is relatively rotatable with respect to the intake camshaft 23 penetrating the center thereof.

Further, a ring cover 3 provided to surround the rotating member 33 is provided on the front end surface (left side surface in the figure) of the gear 31.
4 abuts, and the opening at the tip end of the ring cover 34 is closed by a closing plate 35. The gear 31, the ring cover 34, and the closing plate 35 are integrally rotatably fixed by bolts 36. Therefore, the gear 31, the ring cover 34, and the closing plate 35 can rotate relative to the intake camshaft 23 and the rotating member 33 about the axis L of the intake camshaft 23.

Hydraulic oil is supplied to the variable valve timing mechanism 30 from an advance-side oil passage 37 and a retard-side oil passage 38 formed in the cylinder head 15 and the intake camshaft 23 as shown in the figure. When the variable valve timing mechanism 30 is operated by supplying the hydraulic oil in this manner, the relative rotation phase of the intake camshaft 23 with respect to the crankshaft 14 is changed to the advance side or the retard side, and accordingly, the valve of the intake valve 21 is changed. The timing will also change.

The advance-side oil passage 37 and the retard-side oil passage 38
Is connected to an oil control valve (OCV) 40. Further, a supply passage 50 and a discharge passage 51 are connected to the OCV 40. The supply passage 50 is connected to an oil pan 11b provided below the internal combustion engine 11 via an oil pump 52 driven by the rotation of the crankshaft 14, and the discharge passage 51 is directly connected to the oil pan 11b. ing.

The OCV 40 is a predetermined number (four in this example)
And a spool 44 urged in opposite directions by a coil spring 42 and an electromagnetic solenoid 43. In the OCV 40, the position (valve position) of the spool 44 is determined based on the duty control of the voltage application to the electromagnetic solenoid 43 by an electronic control unit (hereinafter referred to as ECU) 80.
Is controlled.

That is, the ECU 80 controls the electromagnetic solenoid 4
3 is (50% <D ≦
100%), the spool 44 is moved toward one end (left side in the figure) against the urging force of the coil spring 42.
Placed in In this state, the advance-side oil passage 37 communicates with the supply passage 50, and the hydraulic oil in the oil pan 11b is sent out to the advance-side oil passage 37 by the oil pump 52, and the retard-side oil passage The hydraulic oil in the retard-side oil passage 38 is returned to the oil pan 11b through communication between the oil passage 38 and the discharge passage 51.

The ECU 80 controls the electromagnetic solenoid 4
3 is 0% ≦ D <5.
0%), the spool 44 is disposed on the other end side (right side in the drawing) by the urging force of the coil spring 42. In this state, the retard-side oil passage 38 and the supply passage 50 communicate with each other, and the operating oil in the oil pan 11b is sent out to the retard-side oil passage 38 by the oil pump 52, and the advance-side oil passage The hydraulic fluid in the advance-side oil passage 37 is returned into the oil pan 11b through communication between the exhaust passage 51 and the exhaust passage 51.

The ECU 80 controls the electromagnetic solenoid 4
When the duty ratio D of the voltage application to the coil 3 is set to 50%, the spool 44 is positioned approximately at the one end position and the other end position by the balance between the electromagnetic force of the electromagnetic solenoid 43 and the urging force of the coil spring 42. It is located at an intermediate position.
In this state, the advance-side oil passage 37 and the retard-side oil passage 3
8 are communicated with the supply passage 50, and hydraulic oil is sent out to both of these oil passages 37 and 38.

Next, the detailed structure of the rotating member 33 and the ring cover 34 in the variable valve timing mechanism 30 will be described with reference to FIG. As shown in FIG. 3, the inner peripheral surface 34a of the ring cover 34 has an intake camshaft 2
3, four convex portions 34b protruding toward the axis L (see FIG. 2) are formed at predetermined intervals in the circumferential direction of the ring cover 34. The concave portions 34c are formed at predetermined intervals in the circumferential direction of the ring cover 34 between the respective convex portions 34b. In addition, the rotating member 33
Four vanes 33a projecting outward from the outer peripheral surface so as to be inserted into the respective concave portions 34c are provided. Each recess 3
The space formed by the gear 4c, the gear 31, and the closing plate 35 is partitioned by the vane 33a into an advance pressure chamber 53 and a retard pressure chamber 54. The advance pressure chamber 53 and the retard pressure chamber 54 are positioned so as to sandwich the vane 33 a from both sides in the circumferential direction of the rotating member 33. The advance side oil passage 37 formed so as to pass through the inside of the rotating member 33 is connected to the advance side pressure chamber 53, and the retard side pressure chamber 5
4 is connected to the retard side oil passage 38 formed so as to pass through the gear 31.

In such a variable valve timing mechanism 30, the duty ratio D of voltage application to the electromagnetic solenoid 43 of the OCV 40 by the ECU 80 is (50% <D
≦ 100%), hydraulic oil is supplied from the advance-side oil passage 37 to the advance-side pressure chamber 53, and from the retard-side pressure chamber 54 via the retard-side oil passage 38. Hydraulic oil is discharged. As a result, the relative movement of the vanes 33a in the direction of arrow A causes the rotation of the rotating member 33 to the right in the drawing, thereby changing the relative rotational phase of the intake camshaft 23 with respect to the gear 31 (crankshaft 14). . Incidentally, in the variable valve timing mechanism 30, the rotation of the crankshaft 14
1, the gear 31 and the intake camshaft 23 both rotate rightward in the figure. Therefore, the arrow A
When the relative movement of each vane 33a in the direction is performed, the intake camshaft 23 rotates relatively to the advance side with respect to the crankshaft 14, and as a result, the valve timing of the intake valve 21 also advances.

When the duty ratio D of voltage application to the electromagnetic solenoid 43 of the OCV 40 is set in the range of (0% ≦ D <50%) by the ECU 80, the retard side oil passage 38 to the retard side pressure chamber 54 The hydraulic oil is supplied to the hydraulic fluid, and the hydraulic oil is discharged from the advanced pressure chamber 53 through the advanced oil passage 37. As a result, each vane 33a has an arrow A
, The rotating member 33 relatively rotates leftward in the same direction, and the gear 31 (the crankshaft 1).
The relative rotation phase of the intake camshaft 23 with respect to 4) is changed in the opposite direction. In this variable valve timing mechanism 30, in this case, the intake camshaft 23 rotates relative to the crankshaft 14 in the retard side, and as a result, the valve timing of the intake valve 21 also retards.

The ECU 80 controls the electromagnetic solenoid 4
When the duty ratio D of the voltage application to the pressure chamber 3 is set to 50%, the two pressure chambers 53 and 54
Is supplied with hydraulic oil. As a result, each of the pressure chambers 53, 54
The force acting on each vane 33a is balanced in accordance with the hydraulic pressure, and the relative rotation of the rotating member 33 is stopped. Therefore, in this case, the valve timing of the intake valve 21 is maintained at the current timing.

Accordingly, the ECU 80 changes the duty ratio D of voltage application to the electromagnetic solenoid 43 between 0% and 100% based on the deviation between the actual relative rotation phase of the intake camshaft 23 and the target phase. The supply and discharge of hydraulic oil to and from the angular pressure chamber 53 and the retard pressure chamber 54 are controlled, and the hydraulic pressure in the pressure chambers 53 and 54 is feedback-controlled. By performing feedback control of the hydraulic pressure in the advance pressure chamber 53 and the retard pressure chamber 54 in this manner, it is possible to change the valve timing of the intake valve 21 or to maintain the intake valve 21 in a predetermined state.

Here, when the internal combustion engine 11 is started, the operating oil may be released from the advance side pressure chamber 53 and the retard side pressure chamber 54 in some cases. Even if the supply of hydraulic oil to the pressure chambers 53 and 54 starts, sufficient hydraulic pressure does not act on the rotating member 33. Therefore, until a predetermined period elapses from the start of the start of the internal combustion engine 11, the camshaft 2 is operated by the lock mechanism 60 described later.
3 is locked to an intermediate phase θ between the most retarded state and the most advanced state (hereinafter referred to as an intermediate stop). In the present embodiment, the intermediate phase θ
Is set to a phase suitable for starting the internal combustion engine 11, that is, the valve timing of the intake valve 21 is set to a timing suitable for starting the engine 11 (hereinafter referred to as a start timing).

FIGS. 3 and 4 show a structure for stopping the valve timing of the intake valve 21 at the intermediate position as described above, that is, a structure for locking the relative rotational phase of the intake camshaft 23 with respect to the crankshaft 14. FIG. It will be described with reference to FIG.

As shown in FIG. 3, in the variable valve timing mechanism 30, the relative rotational phase of the intake camshaft 23 is locked on both the advance side and the retard side when the valve timing is the start timing. Locking mechanism 60 is provided. The detailed structure of the lock mechanism 60 is shown in FIG. FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3, and shows a state in which the relative rotation phase of the intake camshaft 23 is locked by the lock mechanism 60.

As shown in FIG. 4, a receiving hole 64 extending in the axial direction of the intake camshaft 23 is formed in one of the vanes 33a. This accommodation hole 64 has the same hole 64
A lock pin 62 that can reciprocate within the lock pin 62
And a coil spring 61 for urging the gear 31 toward the gear 31 are accommodated. The gear 31 has a hole 63 into which the tip of the lock pin 62 can be inserted when the gear 31 and the vane 33a are at positions corresponding to the start timing.

A flange 62a is formed on the outer peripheral surface of the lock pin 62, and a cylindrical holding member 65 in which the lock pin 62 is fitted is disposed in the accommodation hole 64 at a position closer to the closing plate 35 than the flange 62a. Has been established. The advance-side oil chamber 66 is formed by an annular space defined by the holding member 65 and the lock pin 62 in the housing hole 64. The oil chamber 66 is connected to the advance pressure chamber 5 through a passage 67.
The working oil is supplied from the advance angle side pressure chamber 53. The position of the flange 62 a changes from a position closer to the gear 31 than the opening of the passage 67 to a position closer to the holding member 65 than the opening of the passage 67 with the reciprocating movement of the lock pin 62. On the other hand, the hole 63 of the gear 31
, A retard-side oil chamber 68 is formed between the bottom thereof and the tip end surface of the lock pin 62. This oil chamber 68
It communicates with the retard pressure chamber 54 via a passage 69, and hydraulic oil is supplied from the retard pressure chamber 54.

The lock mechanism 60 controls the pressure of the hydraulic oil supplied to the advance side pressure chamber 53 and the retard side pressure chamber 54,
That is, the intermediate stop of the relative rotation phase of the intake camshaft 23 and the release of the intermediate stop are performed in accordance with the oil pressure in the pressure chambers 53 and 54.

That is, during the operation of the engine, when the lock pin 62 comes out of the hole 63 and the flange 62a is located closer to the holding member 65 than the opening of the passage 67 (see FIG. 4 (b)). Either the urging force for urging the flange 62a toward the holding member 65 by the hydraulic pressure of the angular oil chamber 66 or the urging force for urging the distal end of the lock pin 62 toward the closing plate 35 by the hydraulic pressure of the retarding oil chamber 68. As a result, the lock pin 62 has the hole 6 against the urging force of the coil spring 61.
3 is maintained. At this time, the lock (intermediate stop) on the advance side and the retard side of the relative rotation phase of the intake camshaft 23 by the lock mechanism 60 is maintained in a released state.

On the other hand, in the process of stopping the internal combustion engine 11,
When the rotation speed of the crankshaft 14 decreases, the amount of hydraulic oil sent to the pressure chambers 53 and 54 by the oil pump 52 decreases. Therefore, each of these pressure chambers 5
The hydraulic pressure of the lock mechanism 60 decreases accordingly.
The oil pressure in each of the oil chambers 66, 68 also decreases. When these oil pressures decrease to a value at which the lock pin 62 cannot be inserted into the housing hole 64 against the urging force of the coil spring 61, the lock pin 62 is moved by the urging force of the coil spring 61. Try to protrude from In such a state, when the accommodation hole 64 overlaps the hole 63, that is, when the valve timing is the start timing, the lock pin 62 projects and is inserted into the hole 63, and the relative rotation phase of the intake camshaft 23 advances. Lock on both the corner side and the retard side (intermediate stop)
Is done.

Even if the locked state is not reached when the internal combustion engine 11 is stopped, if the relative rotation phase of the intake camshaft 23 is on the advanced side of the intermediate phase θ, the engine 11 When starting, the intake camshaft 23
When the relative rotation phase is changed to the retarded side by the reaction force due to the opening and closing of the intake valve 21 and becomes the intermediate phase θ, the lock pin 62 is inserted into the hole 63 and locked (intermediate stop). .

When the relative rotation phase of the intake camshaft 23 is stopped at an intermediate phase by the lock pin 62, the duty ratio D is set to 100%, and hydraulic oil is supplied only to the advance pressure chamber 53. Then, the flange 62 a of the lock pin 62 is urged toward the gear 31 by the hydraulic pressure of the advance-side oil chamber 66, and the lock pin 62 is attached to the hole 63 by the urging force and the urging force of the coil spring 61. Therefore, the intermediate stop state is maintained (forced intermediate stop).

The internal combustion engine 11 is provided with various sensors for detecting the relative rotational phase of the intake camshaft 23 and determining the timing for performing the above-mentioned forced intermediate stop control.

That is, as shown in FIG.
Is provided with a water temperature sensor 55 for detecting the temperature of the cooling water. A crank position sensor 56 for detecting the rotation angle is provided near the crankshaft 14, and a cam position sensor 57 for detecting the rotation angle is provided near the intake camshaft 23. . The output signals of these sensors 55 to 57 are output from the ECU 8
Input to 0. The ECU 80 calculates the actual relative rotational phase of the intake camshaft 23 based on the output signals of the sensors 56 and 57 thus input. Also, ECU
Reference numeral 80 denotes the fuel injection valve 25, the spark plug 26, and O
CV40 is connected. Then, the ECU 80
These fuel injection valve 25, spark plug 26 and OCV 40
Output a drive signal. This ECU 80
CPU, memory, and input / output ports (all not shown)
And the like.

Further, as shown in FIG.
80 is connected to the battery 83 via the IG switch 58 and the main relay 81. Main relay 81
Is provided with a contact 81a and an exciting coil 81b for opening and closing the contact 81a. The ECU 80 controls the power supply to the ECU 80 by controlling the main relay 81 through the main relay drive circuit 80a based on an “ON” / “OFF” operation of the IG switch 58 from the outside.

In the present embodiment, the fuel injection valve 2
An ignition / injection relay 82 that supplies power to the ignition plug 5 and the ignition plug 26 is provided separately from the main relay 81. Like the main relay 81, the ignition / injection relay 82 includes a contact 82a and an excitation coil 82b for opening and closing the contact 82a. Then, the ECU 80
Are "ON" and "OF" of the IG switch 58 from outside.
By controlling the ignition / injection relay 82 through the ignition / injection relay drive circuit 80b provided separately from the main relay drive circuit 80a based on the "F" operation, the power supply to the fuel injection valve 25 and the ignition plug 26 is controlled. I do.

For example, when the IG switch 58 is turned "ON", the ECU 80 sets the main relay drive circuit 80a
At the same time, power is supplied to the ignition / injection relay drive circuit 80b to excite the excitation coils 81b and 82b, respectively. As a result, the contacts 81a and 82a are closed, and the battery 8 is connected to the fuel injection valve 25 and the spark plug 26 together with the ECU 80.
3 supplies power. In this state, the fuel injection valve 25 and the spark plug 26 become operable,
It operates in response to an injection request and an ignition request from the ECU 80.

On the other hand, when the IG switch 58 is turned "OFF", the ECU 80 operates the main relay drive circuit 80 after a predetermined period t1 has elapsed since the "OFF" operation.
The power supply to the ignition / injection relay drive circuit 80b is stopped together with a, and the excitation coils 81b and 82b are respectively demagnetized. As a result, after power is supplied to the ECU 80, the fuel injection valve 25, and the ignition plug 26 for a predetermined period (t1), the contacts 81a and 82a are opened, respectively, and the ECU 80 itself, the fuel injection valve 25 and the Power supply to the ignition plug 26 is stopped.

Incidentally, as described above, the IG switch 58
For a predetermined period (t1) from the time of the “OFF” operation of the ECU 8
The reason why the power supply to the fuel injection valve 25 and the spark plug 26 is continued is that the oil pump 52 is operated by maintaining the rotation of the crankshaft 14 during the stop process of the internal combustion engine 11 to advance the advance angle. By supplying hydraulic oil to the side pressure chamber 53, the valve timing of the intake valve 21 is advanced more than the start timing.

In the above embodiment, the main relay 81
And the ignition / injection relay 82 are provided separately, so that even if the contact 81a of the main relay 81 is closed and the drive request is continuously output from the ECU 80 to the fuel injection valve 25 and the ignition plug 26, the predetermined period t1 has elapsed. Thereafter, the opening of the ignition / injection relay 82 cuts off the power supply to these, so that the internal combustion engine 11 can be stopped.

On the other hand, the contact 82a of the ignition / injection relay 82
Is closed and the power supply to the fuel injection valve 25 and the spark plug 26 is not interrupted, the various controls by the ECU 80 are stopped by the opening of the main relay 81. Is also stopped, so that the internal combustion engine 11 can be stopped.

Further, since the main relay drive circuit 80a and the ignition / injection relay drive circuit 80b are separately provided, even if the contact 81a cannot be opened due to a failure of the main relay drive circuit 80a, the ignition / injection relay circuit 80a is not opened after a predetermined period t1. Since the power supply to the fuel injection valve 25 and the spark plug 26 is stopped by the injection relay drive circuit 80b, the internal combustion engine 11
Can be stopped.

On the other hand, even if the contact 82a cannot be opened due to the failure of the ignition / injection relay drive circuit 80b, the fuel injection valve 2 is stopped by stopping the power supply to the main relay drive circuit 80a.
Since the drive request for the ignition plug 5 and the ignition plug 26 is stopped, the internal combustion engine 11 can be stopped.

Next, with reference to the flow chart of the mode determination routine shown in FIG. 6, the control of the intermediate stop for locking the relative rotation phase of the intake valve 21 to the above-mentioned intermediate phase θ by the lock mechanism 60 and the valve timing will be described. A processing procedure related to control of the forced intermediate stop forcibly holding the intermediate phase θ by the lock mechanism 60 will be described.

First, a processing procedure relating to the control of the intermediate stop will be described. The control of the intermediate stop is performed during the stop process of the internal combustion engine 11. As shown in FIG. 6, during the operation of the intermediate stop, when the internal combustion engine 11 is operating, the ECU 8 executes
0 determines whether or not the intermediate stop execution mode is set. On this occasion,
The ECU 80 determines whether or not the IG switch 58 has been operated "OFF". If the IG switch 58 has been turned OFF, the ECU 80
Determines that there is an engine stop request (step S10: Y
ES), and shift to the intermediate stop execution mode.

When the mode is shifted to the intermediate stop execution mode, the ECU
The duty control 80 controls the voltage application to the electromagnetic solenoid 43 of the OCV 40 to advance the relative rotation phase (valve timing of the intake valve 21) of the intake camshaft 23 from the current state by a predetermined phase θ1 or more. The predetermined phase θ1 is set to a value larger than the phase from the most retarded state of the intake camshaft 23 to the intermediate phase θ. Then, the ECU 80 performs the processes of steps S11 to S15 in parallel with the advance angle control.

As the process of step S11, the ECU 80
Determines whether the elapsed time since the "OFF" operation of the IG switch 58 is performed is within the above-mentioned predetermined period t1.
If the elapsed time is within the predetermined period t1 (step S11: YES), the ECU 80 proceeds to the next step S1.
Step 12 is performed.

As the process of step S12, the ECU 80
Is in the intermediate stop execution mode, that is, the IG switch 5
The maximum value (maximum value of the advance amount from the most retarded state) θmax of the relative rotation phase of the intake camshaft 23 within the predetermined period t1 after the “OFF” operation of No. 8 is performed is stored.

Then, as a process of the next step S13, the ECU 80 determines whether or not the stored maximum value θmax is equal to or greater than the intermediate phase θ, that is, the relative rotational phase of the intake camshaft 23 is equal to or greater than the intermediate phase θ. It is determined whether or not the angle has been changed to the advance side. And this maximum value θm
ax is equal to or greater than the predetermined phase θ1 (step S13: YE
S), the ECU 80 determines that the lock mechanism 60 has locked the relative rotation phase (valve timing of the intake valve 21) of the intake camshaft 23, or determines that the lock will be performed at the next engine start. Step S14 is performed.

As the processing of step S14, the ECU 80
Sets the intermediate stop completion flag F to the "ON" state. On the other hand, if the stored maximum value θmax is less than the intermediate phase θ in the process of step S13 (step S13: NO), the ECU 80 determines that the lock by the lock mechanism 60 is not performed, and Step S
In the process of No. 15, the intermediate stop completion flag F is set to “OFF”
State.

When the predetermined time t1 has elapsed since the "OFF" operation of the IG switch 58 has been performed (step S11: NO), the ECU 80 terminates this routine and executes each of the drive circuits. 80a, 8
The power supply to the ECU 80, the fuel injection valve 25, and the ignition plug 26 is stopped.

On the other hand, if it is determined in step S10 that the mode is not the intermediate stop execution mode,
When the IG switch 58 is in the state of being operated "ON" (step S10: NO), the next step S16
Is performed.

As the process of step S16, the ECU 80
Determines whether the mode is the forced intermediate stop mode. At this time, E
The CU 80 determines whether or not the elapsed time since the start of the internal combustion engine 11 is within the predetermined period t2, and whether the temperature of the cooling water of the internal combustion engine 11 is equal to or lower than the predetermined temperature. And
If both of these conditions are satisfied, the ECU 80 determines that the internal combustion engine 11 is in the starting process (step S16:
YES), the mode shifts to the forced intermediate stop mode.

When the mode shifts to the forced intermediate stop mode, first,
As the process of step S17, it is determined whether or not the intermediate stop completion flag F is in the “ON” state. If the intermediate stop completion flag F is in the “ON” state (step S17: YES), the ECU 80 proceeds to the next step S1.
8 is performed.

As the process of step S18, the ECU 80
Executes the forced intermediate stop control with the duty ratio D set to 100%. Note that the process in step S18 is continuously performed without shifting to the process in the next step S15 while the condition for shifting to the forced intermediate stop mode is satisfied. In this state, the intake camshaft 23
Relative rotation phase (valve timing of intake valve 21)
Is kept locked by the lock mechanism 60.

On the other hand, if the intermediate stop completion flag F is in the "OFF" state in the processing of the previous step S17 (step S17: NO), the ECU 80 proceeds to step S17.
19 is performed.

As the process of step S19, the ECU 80
Sets the duty ratio D to 0%. That is, in this case, the execution of the forced intermediate stop control is prohibited. In this state, supply of hydraulic oil to the advance side pressure chamber 53 for maintaining the locked state is prohibited, and the intake valve 2
1 by the reaction force accompanying the opening and closing drive of the intake camshaft 23.
Becomes the most retarded state, and that state is maintained. For this reason, hydraulic oil is supplied to the advance side pressure chamber 53 in order to maintain the locked state, and the relative rotation phase of the intake camshaft 23 becomes the most advanced state with it, and is changed to a phase that is significantly different from the start timing. There is no such thing. As a result, it is possible to suppress the deterioration of the startability and the emission at the time of starting the internal combustion engine 11.

After performing the processing of step S18 or S19, the ECU 80 sets the intermediate stop completion flag F to the "OFF" state as the processing of the next step S15. After performing the process of step S15, or when the ECU 80 determines that at least one of the above conditions in the process of step S16 is not satisfied (step S16: NO), the ECU 80 ends this routine, Normal valve timing control is performed.

As described in detail above, according to the valve timing control device of this embodiment, the following effects can be obtained. (1) When the relative rotation phase of the intake camshaft 23 is not locked by the lock mechanism 60, the supply of the hydraulic oil to the advance side pressure chamber 53 is prohibited. There is no possibility that the phase is changed to a phase that is significantly different from the above-mentioned start timing due to the advanced angle state.
As a result, it is possible to suppress the deterioration of the startability and the emission at the time of starting the internal combustion engine 11.

(2) When the internal combustion engine 11 is stopped, the inside of the advance side pressure chamber 53 and the phase of the retard side pressure chamber 54 are set so that the relative rotation phase of the intake camshaft 23 is more advanced than the intermediate phase θ. In order to determine that the lock by the lock mechanism 60 has not been performed based on the fact that the maximum value θmax of the relative rotation phase of the camshaft 23 during the predetermined period t1 has not reached the predetermined phase θ1. Although the locked state is not obtained when the engine is stopped, it is possible to determine that the locked state has been achieved at the next start of the engine without fail, so that the determination can be performed more accurately. Become like

The above embodiment can be appropriately modified, for example, as follows. In the above embodiment, when the lock mechanism 60 does not stop the intermediate rotation of the relative rotation phase of the intake camshaft 23 during the starting process of the internal combustion engine 11, the supply of the hydraulic oil to the advance pressure chamber 53 is performed. Was banned. However, in this case, in addition to the hydraulic oil supply prohibition process,
For example, as shown in FIG. 7, at least one of the following processes is performed as the process of step S20: increasing the fuel injection amount, changing the ignition timing to the advanced side, increasing the intake air amount by idle speed control. You may. With this configuration, in addition to the above effects, the internal combustion engine 1
The combustion of the air-fuel mixture in the start-up process 1 is stabilized, and deterioration of emission and drivability can be suppressed.

In the above embodiment, the determination as to whether or not the lock mechanism 60 has been locked (step S13) is made when the internal combustion engine 11 is stopped, but the maximum relative rotational phase of the intake camshaft 23 is determined. The value θmax may be stored until the next engine start, and this determination may be made when the engine 11 is started.

(Second Embodiment) Next, a second embodiment of the valve timing control device of the present invention will be described with reference to FIG.

In this embodiment, if the lock mechanism 60 is not locked when the internal combustion engine 11 is stopped, the relative rotational phase of the intake camshaft 23 is changed to the intermediate phase θ (start timing) at the next engine start. The feedback control of the oil pressure of both pressure chambers 53 and 54 is performed so that In the following description, only a control mode different from that of the first embodiment will be described regarding the control mode at the time of starting the engine, and a detailed description of the same portions as the first embodiment will be omitted.

FIG. 8 is a flowchart showing a part of the mode determination routine of this embodiment. Note that, also in the series of processing shown in FIG. 8, the series of processing in steps S10 to S16 shown in FIG. 6 is performed in the same manner as in FIG.

As shown in FIG. 8, the condition for shifting to the forced intermediate stop mode is satisfied (step S16: YES),
If the intermediate stop is performed when the engine 11 is stopped (step S17: YES), the ECU 80 executes the forced intermediate stop (step S18).

On the other hand, in the process of step S17, when it is determined that the intermediate stop is not performed (step S17).
17: NO), the ECU 80 changes the relative rotational phase of the intake camshaft 23 to the intermediate phase θ based on the deviation between the actual relative rotational phase of the intake camshaft 23 and the target intermediate phase θ. The hydraulic pressures of the angular pressure chamber 53 and the retard pressure chamber 54 are feedback-controlled (hereinafter referred to as abnormal-time feedback control).

At this time, first, as the processing of step S21, the ECU 80 sets the target phase θt for the relative rotational movement of the intake camshaft 23 to the intermediate phase θ. Next, as the process of step S22, the ECU 80 sets the feedback gain used for calculating the duty ratio D in the abnormal-time feedback control after the predetermined period t2 has elapsed from the engine start (step S16 in FIG. 7). : NO) is set to an abnormal-time feedback gain Kb (Kb> Ka) which is larger than the feedback gain Ka used for normal feedback control performed in (NO).

The duty ratio D is calculated based on, for example, the following equation. D ← 50% −Kb (θa−θt) θa: Actual relative rotational phase of the intake camshaft θt: Target phase When these steps S21 and S22 are performed, the ECU 80 executes the feedback control at the time of abnormality. I do. The valve timing control by the abnormal-time feedback control is continuously performed without shifting to the next step S15 while the transition condition of the forced intermediate stop mode is satisfied. Then, the ECU 80
Determines that at least one of the two conditions in step S16 is not satisfied (step S16:
NO), this routine ends, and normal valve timing control (feedback control) is performed.

As described in detail above, according to the valve timing control device of this embodiment, the following excellent effects can be obtained. (1) The relative rotation phase of the cam shaft 23 is
0, the advance pressure chamber 5 is adjusted so that the relative rotational phase becomes the intermediate phase θ to be locked.
3 and the hydraulic pressure of the retard pressure chamber 54 are feedback controlled. For this reason, it is possible to suppress the relative rotational phase from shifting to the most retarded state due to the reaction force accompanying the opening / closing drive of the intake valve 21, and to make the relative rotational phase closer to the intermediate phase θ suitable for starting the engine. It is possible to suppress the deterioration of the startability and the emission at the time of starting the engine 11.

(2) When performing the feedback control as described above, the abnormal-time feedback gain Kb is set to be larger than the normal feedback gain Ka.
When the amount of hydraulic oil supplied to the advance pressure chamber 53 and the retard pressure chamber 54 cannot be sufficiently secured, such as when starting the engine, the actual relative rotational phase of the camshaft 23 is set to the target phase θt. , As close as possible to the intermediate phase θ.

The second embodiment can be appropriately changed, for example, as follows. In the above-described embodiment, the target phase θt is set to the intermediate phase θ, which is the start timing, at the time of abnormal-time feedback control
However, the target phase θt can be set arbitrarily. The same phase θt may be, for example, a phase near the intermediate phase θ.

In the above embodiment, the abnormal-state feedback gain Kb is set to be larger than the feedback gain Ka used in the normal feedback control after the predetermined period t2 has elapsed in the abnormal-state feedback control. However, the abnormal-time feedback gain Kb may be set smaller than the normal feedback gain Ka. If you do this,
The convergence at the time of converging the actual relative rotation phase of the intake camshaft 23 to the intermediate phase θ can be enhanced to suppress the occurrence of hunting.

In the above embodiment, the intake camshaft 2
When the relative rotation phase of No. 3 is not locked by the lock mechanism 60, the feedback control is performed.
This control may be an open loop control.

In addition, the following are common elements that can be changed in the above embodiments. In the above embodiments, the determination whether or not the relative rotation phase of the intake camshaft 23 has been locked by the lock mechanism 60 (step S13) is based on whether or not the maximum value θmax of the relative rotation phase is equal to or greater than the intermediate phase θ. That is, the determination is made based on whether the maximum value θmax is the same as the intermediate phase θ or on the advance side of the intermediate phase θ. But,
This determination is not limited to this. This is determined, for example, by determining whether the relative rotational phase of the intake camshaft 23 when the internal combustion engine 11 is stopped (the state at the start of starting) is the same as the intermediate phase θ or is on the more advanced side than the intermediate phase θ. You may make it.

The determination is made as to whether the maximum value θmax of the relative rotation phase is within a predetermined range, for example, whether the maximum value θmax is within a predetermined range centered on the intermediate phase θ. It may be performed depending on whether or not. Also in this case, instead of the maximum value θmax, the relative rotation phase of the intake camshaft 23 when the internal combustion engine 11 is stopped (starting state) can be used.

In the above embodiments, each of the relays 81, 8
2 are contact points 81a, 82a and an exciting coil 81, respectively.
b, 82b. However, these relays 81 and 82 are not limited to mechanical ones. These relays may use, for example, semiconductor elements such as switching elements.

In each of the above embodiments, the ignition / injection relay 82 is provided as a relay for supplying power to the fuel injection valve 25 and the ignition plug 26, but power is supplied to the fuel injection valve 25 and the ignition plug 26. May be separately provided.

In the above embodiments, the excitation coil 81b of the ignition / injection relay 82 is connected to the ignition / injection relay drive circuit 80b of the ECU 80. However, the present invention is not limited to this configuration. For example, the excitation coil 81b may be connected to the main relay drive circuit 80a of the ECU 80 together with the contact point 81a of the main relay 81 by omitting the ignition / injection relay drive circuit 80b.

In the above embodiments, the variable valve timing mechanism 30 is provided only on the intake camshaft 23. However, the variable valve timing mechanism is provided only on the exhaust camshaft 24 or on the intake camshaft 23 and the exhaust camshaft. It may be provided on both of the camshaft 24. When controlling the variable valve timing mechanisms provided in each of the camshafts, the control modes shown in the above embodiments can be applied.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an internal combustion engine to which a first embodiment of a valve timing control device of the present invention is applied.

FIG. 2 is an exemplary sectional view showing a structure for supplying hydraulic oil to the variable valve timing mechanism according to the embodiment;

FIG. 3 is a sectional view showing an internal structure of the variable valve timing mechanism.

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3;

FIG. 5 is a block diagram showing an electrical configuration of the valve timing control device.

FIG. 6 is a flowchart illustrating a processing procedure for mode determination of the internal combustion engine.

FIG. 7 is a flowchart showing a part of a processing procedure related to a mode determination according to another example.

FIG. 8 is a flowchart showing a part of a processing procedure for mode determination according to the second embodiment;

[Explanation of symbols]

11 internal combustion engine, 14 crankshaft, 21 intake valve, 22 exhaust valve, 23 intake camshaft,
24: exhaust camshaft, 30: variable valve timing mechanism, 33: rotating member, 37: advanced oil passage, 38: retard oil passage, 40: oil control valve (OCV),
52: oil pump, 55: crank position sensor, 56: water temperature sensor, 57: cam position sensor,
53: advance side hydraulic chamber, 54: retard side hydraulic chamber, 80: electronic control unit (ECU).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F02D 41/22 320 F02D 41/22 320 F term (Reference) 3G018 AB07 AB17 BA09 BA10 BA33 CA19 DA57 DA74 DA77 EA02 EA16 EA21 EA33 FA01 FA07 GA09 GA11 GA38 GA40 3G092 AA11 BA09 BB02 DA09 DE01Y DG05 EA03 EA13 EC01 FA11 FA15 FA31 FA44 GA01 HA01Z HA13Z HE01Z HE03Z HE08Z 3G301 HA19 JA03 JA08 JB02 KA01 LA07 LB01 PE01Z01 PE01Z

Claims (6)

[Claims] A variable valve timing mechanism for changing a relative rotation phase of a camshaft with respect to a crankshaft of an internal combustion engine based on fluid pressures of an advance side pressure chamber and a retard side pressure chamber; A lock that locks at an intermediate phase between the most retarded state and the most advanced state, and maintains the locked state based on the fluid pressure of at least one of the advance side pressure chamber and the retard side pressure chamber. Means for controlling the fluid pressure in the one pressure chamber until a predetermined period has elapsed from the start of the engine so as to maintain the locked state of the lock means. Determining means for determining that the relative rotation phase is not locked by the locking means; and determining the relative rotation phase by the locking means. Tsu valve timing control apparatus for an internal combustion engine and a prohibiting means based on be determined that the non-click prohibiting control fluid pressure of the one pressure chamber by said control means. 2. The system according to claim 1, wherein the determining means determines that the locking by the locking means has not been performed based on the fact that the relative rotational phase at the time of engine start is a phase on the more retarded side than the intermediate phase. 3. The valve timing control device for an internal combustion engine according to claim 1. 3. The control means controls the fluid pressures of the two pressure chambers for a predetermined period when the engine is stopped so that the relative rotational phase is on the more advanced side than the intermediate phase. The means determines that the locking by the locking means has not been performed based on the fact that the relative rotation phase has not reached the intermediate phase during the predetermined period in which the fluid pressure in the pressure chambers is controlled by the control means. 2. The valve timing control device for an internal combustion engine according to claim 1. 4. A variable valve timing mechanism for changing a relative rotational phase of a camshaft with respect to a crankshaft of an internal combustion engine based on fluid pressures of an advance side pressure chamber and a retard side pressure chamber, and the variable valve timing mechanism controls the cam. Control means for controlling the fluid pressure in the two pressure chambers to change the relative rotational phase of the shaft to the target phase, and the relative rotational phase of the camshaft to an intermediate phase between the most retarded state and the most advanced state. A valve timing control device for an internal combustion engine, comprising: locking means for locking; and determining means for determining that the relative rotational phase of the camshaft is not locked by the locking means. Based on the determination that the relative rotation phase is not locked by the locking means, the target phase The valve timing control apparatus for an internal combustion engine, characterized in that it shall be set to the intermediate phase until Luo predetermined period elapses. 5. The valve timing control device for an internal combustion engine according to claim 4, wherein said control means is configured to control the fluid in said two pressure chambers based on a degree of deviation between an actual relative rotation phase of said camshaft and said target phase. A valve timing control device for an internal combustion engine that performs feedback control of pressure. 6. The valve timing control apparatus for an internal combustion engine according to claim 5, wherein said control means sets said target phase to said intermediate phase until a predetermined period has elapsed since the start of said engine, and controls the fluid in said two pressure chambers. A valve timing control device for an internal combustion engine, wherein when performing pressure feedback control, the feedback gain is set to be larger than the feedback gain after the predetermined period has elapsed.