JP2000073793A - Control method for valve timing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a switch control valve from being continuously opened by setting a target valve timing to a timing more advanced than the most lag timing by a prescribed phase and by feedback controlling the switch control valve to turn the practical valve timing to the set target valve timing. SOLUTION: Whether an idle switch is turned on or off is judged (S1), if it is turned on, it is judged to be in an idling state and whether the engine rotation speed is larger than a preset rotation speed KEGFR is judged (S3). If it is larger, a target valve timing VTT value is set according to the driving state with the engine rotation speed Ne set to a parameter, however, the prescribed operation state is set to a timing more advanced than the most lag timing by prescribed phase (S4). Since the practical valve timing is feedback controlled so as to be a target valve timing VTT, the switch control valve is opened, only when the valve timing is required to be corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a valve timing mechanism of a hydraulic pressure type which is applied to an internal combustion engine and can freely change valve timings for opening and closing an intake valve and an exhaust valve.

[0002]

2. Description of the Related Art A valve timing mechanism is used to freely change the opening / closing timing (hereinafter referred to as valve timing) of an intake valve and an exhaust valve in accordance with the operating state of an engine, thereby increasing output and improving drivability. It has been developed in order to achieve this, and various types are conventionally considered.

[0003] Of these, a valve timing mechanism of a hydraulic drive system, which is known as a typical one, is provided via a disk-shaped housing which is fixed to any one of the camshafts at an arbitrary phase angle. The rotation of the crankshaft is transmitted to the intake camshaft, and the valve timing of the intake valve can be freely changed by changing the phase angle of the housing with respect to the intake camshaft. Specifically, the room provided inside this housing,
The vane is fixed to a camshaft and divided into two chambers, an advance chamber and a retard chamber. Then, the hydraulic oil is guided to one of the advance chamber and the retard chamber, and the hydraulic oil is discharged from the other, so that the phase angle of the housing with respect to the camshaft changes.

A spool type four-way electromagnetic switching control valve (oil control valve) for controlling the flow rate and direction of the hydraulic oil is provided, and the switching control valve is electrically driven by a controller or the like. Then, the actual valve timing is controlled so as to coincide with the target valve timing set according to the operating state.

[0005]

This control is performed on the basis of feedback control in which the spool control amount of the switching control valve is determined from the deviation between the actual valve timing and the target valve timing. However, conventionally, in the high rotation region of the engine, as disclosed in JP-A-8-210158, in order to improve the charging efficiency of the intake air into the combustion chamber by utilizing the intake inertia and the like,
Holding the spool of the switching control valve to one moving end, rotating the housing so that the vane abuts the one moving end, and setting the valve timing of the intake valve to the most retarded state. Maintained and no feedback control is performed. This is because, in the most retarded state, the housing is suppressed from turning to the retarded side and can only be turned to the advanced side. In this way, feedback control is performed in a state where control to one side is restricted. Is extremely difficult to do.

However, in this state, the valve opening area of the switching control valve is maximized, and the valve continues to be opened. Therefore, the retard chamber inside the housing is filled with the hydraulic oil having the system pressure, and the retard angle is retarded. Since the amount of hydraulic oil that leaks from the chamber to the advance chamber increases, the amount of hydraulic oil that must be supplied to the switching control valve becomes extremely large. Specifically, FIG. 9 is a drawing showing the relationship between the position of the spool and the required supply amount of hydraulic oil. As described above, when the spool is at the neutral position, the amount of supplied oil is almost equal to the amount of leakage only at the switching control valve and is minimized. However, when the spool is displaced to one of the moving ends, the amount of supplied oil is reduced. It increases for the reasons mentioned above. Note that the horizontal axis in the figure indicates the duty ratio, which corresponds to the position of the spool.

As a result, the amount of hydraulic oil supplied to other hydraulic circuits is reduced, which may hinder lubrication of a crank or the like necessary especially in a high rotation speed range, or may cause a decrease in system pressure. Also, the hydraulic fluid supplied from the switching control valve to the housing is eventually led as a leak to the cam chamber of the cylinder head.
Since a large amount of hydraulic oil flows into the blow-by passage, there is a concern that the blow-by function may be impaired.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and in the prior art, a predetermined operating state in which the switching control valve has been continuously opened in a direction of retarding the switching control valve. In the above, the target valve timing is set to a timing advanced by a predetermined phase from the most retarded timing, thereby enabling feedback control and preventing the switching control valve from being kept open, and supplying the switching control valve to the variable valve timing mechanism. The purpose is to reduce the amount of hydraulic fluid.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The valve timing control method according to the present invention controls a switching control valve capable of changing a flow rate and a direction of a hydraulic fluid supplied from an external hydraulic pressure source to control an exhaust valve and an intake valve. Applied to a hydraulic variable valve timing mechanism of an internal combustion engine configured to be able to freely change at least one of the valve timings related to opening and closing, wherein the internal combustion engine is operated in a predetermined operating state such as a high rotation state. In some cases, the target valve timing is set to a timing advanced by a predetermined phase from the most retarded timing, and the switching control valve is feedback-controlled so that the actual valve timing becomes the set target valve timing. And

In such a case, the target valve timing is set to a timing advanced by a predetermined phase from the most retarded timing even in a predetermined operating state in which the switching control valve is conventionally kept open in the direction of retarding. Since the setting and the feedback control are performed, the switching control valve is opened only when it is necessary to correct the valve timing, and otherwise, the switching control valve is closed. As a result, it is possible to avoid a situation in which the switching control valve continues to be opened, and it is possible to reduce a leak amount due to a decrease in the hydraulic fluid pressure in the variable valve timing mechanism, thereby making it possible to reduce the supplied hydraulic fluid amount. . In particular, since the switching control valve is actually controlled in the closed state or in the vicinity of the closed state, the effect of reducing the supply hydraulic fluid amount is very remarkable. Therefore, there is a fear that the lubrication of the crank or the like may be hindered or the system hydraulic pressure may be reduced.
It is possible to eliminate the concern that a large amount of hydraulic fluid flows into the blow-by passage and impairs the blow-by function.

Preferably, the predetermined phase, which is an advance amount for enabling feedback control, is set within a range that hardly affects the performance of the internal combustion engine, such as output and drivability.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram schematically showing the configuration of an engine 1 (only one cylinder is shown), which is an internal combustion engine, to which the present invention is applied. The engine 1 is, for example, a three-cylinder engine for a car, and has a throttle valve 5, a surge tank 6, which opens and closes in conjunction with an accelerator pedal (not shown).
A cylinder provided with an intake system having an intake pipe 7 and the like, a fuel injection valve 8 arranged near the end of the intake system for performing fuel injection, and a combustion chamber 10a for burning an air-fuel mixture by ignition by a spark plug 9 10 and an exhaust system up to a muffler (not shown). In this combustion chamber 10a,
An intake valve 2 and an exhaust valve 3 are provided so as to open and close in synchronization with engine rotation by a cam mechanism. These intake and exhaust valves 2 and 3 are provided with stems 2a and 3a extending upward, respectively. A valve spring and valve lifters 2b and 3b (not shown) are provided above the stems 2a and 3a.
Etc. are respectively assembled. Each valve lifter 2
b and 3b are respectively in contact with cams 13 and 14 formed on the intake side camshaft 11 and the exhaust side camshaft 12, respectively.

As shown in FIGS. 2 and 3, a timing pulley 15 provided at one end of the exhaust camshaft 12 is provided.
And a timing pulley (not shown) disposed at one end of the crankshaft of the engine 1
6 are connected. As is well known, the diameter ratio of these timing pulleys is set such that the exhaust-side camshaft 12 makes one rotation while the crankshaft makes two rotations. The intake camshaft 11 is connected to the intake valve 2.
In order to make the valve timing of the exhaust valve 3 variable with respect to the valve timing of the exhaust valve 3, it is connected to the exhaust camshaft 12 via a variable valve timing mechanism 4.

The variable valve timing mechanism 4 utilizes a so-called oscillating cylinder structure and is driven by hydraulic pressure. In this embodiment, as shown in FIGS. And an oil control valve 19 (hereinafter referred to as an OCV) as a switching control valve for rotating the housing 18 with respect to the rotor 17, one of which is fixed to the housing 18 so as to mesh with each other. And a pair of gears 20 and 21 having the other fixed to the intake side camshaft 11. Thus, by changing the relative angle of the housing 18 with respect to the rotor 17, an arbitrary rotation phase difference can be generated between the exhaust-side camshaft 12 and the intake-side camshaft 11. As is well known, the gear 20,
21 is set to be 1: 1 and the rotational speeds of the intake camshaft 11 and the exhaust camshaft 12 are set to be the same.

The rotor 17 has a cylindrical shape, an inner surface 17a of which is externally fitted to and fixed to the exhaust camshaft 12, and, for example, four vanes 22 projecting from the outer surface 17b in the radial direction. . The housing 18 has a disk shape having a through hole in the center, and is rotatably attached to the rotor 17 by fitting the through hole outside. The housing 18 is provided with four chambers 18a, which are fan-shaped in front view and open to the side surfaces of the through-holes, at equal intervals along the circumferential direction. As described above, when the housing 18 is externally fitted to the rotor 17, Each vane 22 is in its own room 18a.
Is divided into two, an advance chamber 18b and a retard chamber 18c.

The OCV 19 is a so-called electromagnetic type four-way spool valve as shown in FIG.
9a and 19b and two output ports 19c and 19d. When the spool 19e moves forward and backward, the fluid path inside the spool 19e is switched, and the output ports 19c, 1
9d is communicated with each of the input ports 19a and 19b, or the internal fluid path is cut off so that the output ports 19c and 19d are not communicated with the input ports 19a and 19b. FIG. 3 shows the spool 19e.
Is in a neutral position and blocks the internal fluid path. The advance / retreat of the spool 19e is performed by an OCV drive signal a which is a valve control signal input from the outside, and the advance / retreat distance of the spool 19e is changed according to the on / off duty ratio DVT which is the value of the OCV drive signal a. It is configured so that it can be performed. Specifically, when the duty ratio DVT is 0% (off state), the spool 19
e is located at one moving end (the left side in FIG. 3), and the input port 19a and the output port 19c, and the input port 19b and the output port 19d are connected with the valve opening area being maximized. From this state until the spool 19e reaches the duty ratio DVT (holding duty ratio GDVTH) at which the spool 19e is in the neutral position, the connection state described above is not switched, and the other end of the spool 19e is changed according to the increase in the duty ratio DVT. Side (right side in the figure) to reduce the valve opening area. Then, the duty ratio DVT becomes the holding duty ratio GDVTH,
When the spool 19e is in the neutral position, the OCV
19 has a valve opening area of substantially 0, and each input port 19a, 1
9b and the output ports 19c and 19d are almost completely shut off. When the duty ratio DVT is further increased, the connection state is switched, and the input port 19a and the output port 19 are switched.
d, and the input port 19b and the output port 19c are connected. Then, the spool 19e moves toward the other end according to an increase in the duty ratio DVT to increase the valve opening area. When the duty ratio DVT is 100% (ON state), the spool 19e is located on the other moving end side, and its valve opening area is the largest.

Next, the hydraulic path of the variable valve timing mechanism 4 will be described. As shown in FIGS. 3 to 5, the power source of the variable valve timing mechanism 4 is the engine 1.
The output of the hydraulic pump P driven by the
Of the OCV1
The other input port 19b of 9 is connected to the tank T. These output ports 19c and 19d of the OCV 19
Are connected to one ends of two through holes 12a and 12b provided inside the exhaust side camshaft 12, respectively, and the other ends of the through holes 12a and 12b are connected to the exhaust side camshaft 12 respectively.
Are opened in two grooves 12c and 12d provided in parallel with the outer surface in the circumferential direction. These grooves 1
Reference numerals 2c and 12d are provided at a portion where the rotor 17 is fitted. As shown in FIG. 4, the rotor 17 has a first fluid path 17 c having one end opened to the other groove 12 d and the other end opened to an advance chamber 18 b partitioned by the vane 22.
As shown in FIG. 5, a second fluid path 17d having one end opened in one groove 12c and the other end opened in a retard chamber 18c partitioned by a vane 22 is provided.

The first state in which the pump P communicates with the advance chamber 18b, the tank T communicates with the retard chamber 18c, and the pump P operates with the retard chamber 18c.
The second state in which the tank T communicates with the advance chamber 18b and the third state in which the pump P and the tank T do not communicate with either the retard chamber 18c or the advance chamber 18b move the spool 19e of the OCV 19 forward or backward. It is realized by moving.

That is, by controlling the OCV 19 to maintain the first state, the oil is guided to the advance chamber 18b to increase its capacity, and the vane 22 is rotated to the most advanced position where it comes into contact with one end of the chamber 18a. Can be done. This acts to shift the valve timing of the intake valve 2 described later to the advance side. Further, by holding the second state, the oil is guided to the retard chamber 18c, the capacity thereof is increased, and the vane 22 can be rotated to the most retarded position where it comes into contact with the other end of the chamber 18a. This is intake valve 2
Of the valve timing is shifted to the retard side. The rotation speed of the vane 22 in these first and second states can be set by the duty ratio DVT of the OCV drive signal a. Further, when the vane 22 is stopped during that time, it may be held in the third state. Vane 2 like this
By rotating 2, the relative angle of the housing 18 to the rotor 17 can be arbitrarily changed within a predetermined angle range.

On the other hand, the intake-side camshaft 11 is
The housing 20 is interlocked with the housing 18 via gears 20 and 21, and the exhaust side camshaft 12 is connected to the rotor 17.
And rotate together. Therefore, as described above, by changing the relative angle of the housing 18 with respect to the rotor 17, the rotational phase difference between the intake camshaft 11 and the exhaust camshaft 12 can be arbitrarily set within a predetermined angle range.

The variable valve timing mechanism 4 is constructed as described above, and the valve timing of the intake valve 2 is changed while opening and closing the exhaust valve 3 at a constant timing with respect to the rotation of the crankshaft. And the relative phase difference between the valve timing of the intake valve 2 and the valve timing of the intake valve 2 can be freely changed within a predetermined angle range.

The electric control according to the above-described configuration is performed by the electronic control unit 24. Main sensors, electric wiring, and the like related to the electric control of the present embodiment, including the electronic control device 24, will be described in detail below. As shown in FIGS. 1 and 2, for example, the following sensors are provided as main sensors according to the present embodiment. That is, the exhaust-side camshaft 12 is a pulse signal every time the crankshaft rotates 720 ° CA (hereinafter, when describing the phase of the crankshaft, the angle is expressed by adding CA). It outputs the cylinder discrimination signal c and
An exhaust-side timing sensor 25 that outputs an exhaust cam signal b that is a pulse signal every time the CA rotates is provided. The intake-side camshaft 11 is provided with an intake-side timing sensor 26 that outputs an intake cam signal d, which is a pulse signal, every time the CA is rotated by 240 ° CA. In this embodiment,
As shown in FIG. 2, for example, an exhaust cam signal b output tooth disposed every 120 ° and a cylinder discrimination signal c
A gear 25a having a total of four teeth, including one additional tooth for output, is attached to the timing pulley 15 of the exhaust-side camshaft 12, and a pickup sensor arranged close to the gear 25a. The exhaust-side timing sensor 25
We use as. Similarly, the intake-side camshaft 11 is provided with a total of three gears 26a having teeth for outputting the intake cam signal d arranged at every 120 °, and arranged in close proximity to the gear 26a. The used pickup sensor is used as the intake-side timing sensor 26. In addition, an idle switch 27 that outputs an idle switch signal IDSW when the throttle opening is in an idle state, a power switch 28 that outputs a power switch signal PSW when the throttle opening is more than a certain value,
Alternatively, an intake pipe pressure sensor 29 for detecting the intake pipe pressure PM and outputting an intake pipe pressure signal h is provided. Of course, in addition to the above, various members, sensors, and the like generally used in automobiles also constitute components, but are omitted in this specification.

As shown in FIG. 1, the electronic control unit 24
PU 24a, memory 24b, input interface 24
c, an output interface 24d, etc., which is generally known as a so-called microcomputer device. Various programs for controlling the engine 1 and the like are stored in the memory 24a. The input interface 24c has an exhaust cam signal b, an intake cam signal d,
At least a cylinder discrimination signal c, an idle switch signal IDSW, a power switch signal PSW, an intake pipe pressure signal h, an engine speed signal g, and the like are input. The output interface 24d is configured to output at least an OCV drive signal a which is a control signal of the variable valve timing mechanism 4, a drive signal f of the fuel injection valve 7, an ignition signal e of the spark plug, and the like.

Further, the electronic control unit 24 uses the sensor output information indicating the engine operating state such as the input engine speed signal g, exhaust cam signal b, intake cam signal d, etc. It has at least a function of calculating as a timing (actual valve timing) VT. Schematically, the vane 22 is in the most retarded position,
The output timing of the intake cam signal d0 when the intake valve 2 is in the most retarded state is previously learned and stored, and this is used as a reference phase. The phase difference between the detected intake cam signal d and the learned intake cam signal d0 in the most retarded state is calculated as
The actual valve timing VT is calculated.

In this embodiment, the following control method of the variable valve timing mechanism 4 is employed. That is, when the engine 1 is in a predetermined operating state AR such as a high rotation region, the target valve timing VTT is set to a timing advanced by a predetermined phase from the most retarded timing, and the actual valve timing VT is set to the target valve timing. Feedback control is performed so that the timing becomes VTT.

In the present embodiment, the predetermined operating state AR is a region indicated by hatching in FIG. In this region, as described in the conventional example, in order to improve the performance of the engine 1 by improving the filling efficiency of the intake air into the combustion chamber 10a using the intake inertia and the like, the valve of the intake valve 2 is improved. It is preferable that the timing be most retarded. The timing at which the phase is advanced by a predetermined phase means a timing within a range that hardly impairs the performance of the engine 1 at the most retarded timing. In the present embodiment, the timing is set to be two degrees advanced from the most retarded timing. ing.

More specifically, this control is performed in accordance with a program which is stored in the memory 24b and embodies the flowcharts shown in FIGS. FIG. 7 shows a VTT calculation routine for setting the target valve timing VTT according to the operating state of the engine 1. To elaborate,
In step S1, the idle switch signal IDS
It is determined from the value of W whether the idle switch 27 is on or off. If the idle switch 27 is off, it is determined that the vehicle is not in the idle state, and the process proceeds to step S2. If it is on, it is determined that it is in an idle state, and the process proceeds to step S3.

Step S2 is a portion for performing processing when the vehicle is not in the idle state, and the target valve timing VTT
Is set in accordance with the operating state using the engine speed NE and the intake pipe pressure PM as parameters. In this step S2, conventionally, in the predetermined operating state AR, the value of the target valve timing VTT is set to 0, but in the present embodiment, the value of the target valve timing VTT may not be set to 0. Instead, 2 is set in the predetermined operating state AR. Then, this routine ends (step S6).

Steps S3 to S5 are for setting the target valve timing VTT in the idle state. In step S3, it is determined whether or not the engine speed NE is higher than a predetermined speed KNEGFR. If it is larger, the process proceeds to step S4; otherwise, the process proceeds to step S5.

In step S4, the value of the target valve timing VTT is set according to the operating state using the engine speed NE as a parameter. In this step S4, conventionally, in the predetermined operating state AR, the value of the target valve timing VTT is set to 0, but in the present embodiment, the value of the target valve timing VTT may not be set to 0. Instead, 2 is set in the predetermined operating state AR. Then, this routine ends (step S6).

In step S5, the value of the target valve timing VTT is set to 0, and this routine ends (step S6). As described above, in the VTT calculation routine, the value of the target valve timing VTT is set to 0 only when the process proceeds to step S5, that is, when the engine speed NE is lower than the set speed KEGFR in the idle state. Will be.

On the other hand, FIG. 8 shows an OC according to the value of the target valve timing VTT set in the VTT calculation routine.
9 shows an OCV control routine for controlling V19.
More specifically, in step SS1, it is determined whether or not the value of the target valve timing VTT is 0. 0, that is, the engine is in the idle state and the engine speed N
If E is lower than the set number of revolutions KEGFR, the process proceeds to step SS2; otherwise, the process proceeds to step SS3.

In step SS2, the duty ratio DVT of the OCV drive signal a is set to 0 or smaller than the holding duty ratio GDVTH for holding the spool 19e at the neutral position, and output. Therefore, when the process proceeds to step SS2, the valve timing control is performed in an open loop, and the feedback control is not performed. Then, this routine ends (step SS).
4).

In step SS3, feedback control is performed so that the actual valve timing VT becomes the target valve timing VTT. The parentheses in the figure indicate that during this control, the duty ratio DVT eventually becomes almost the holding duty ratio GDVTH. In such a case, the feedback control is performed even in the predetermined operating state AR in which the OCV 19 is continuously opened in the direction in which the OCV 19 is retarded, so that the OCV 19 is not continuously opened. As a result, the hydraulic oil pressure in the retard chamber 18c becomes lower than the system pressure, and the retard chamber 18c
The amount of hydraulic oil leaking to 8b is smaller than before. Then, the spool 19e almost moves only to replenish the leak amount, and is always in a state near the neutral position, and as shown in FIG. 9, the hydraulic fluid to be supplied to the variable valve timing mechanism 4 The amount can be greatly reduced. Therefore, even when the engine speed NE is high, it is possible to solve the problem that the lubrication of the crank and the like is hindered, the system hydraulic pressure is reduced, and the concern that a large amount of hydraulic fluid flows into a blow-by passage (not shown). it can.

Since the predetermined phase, which is an advance amount for enabling feedback control, is set to a very small angle of 2 degrees, it hardly affects the performance of the internal combustion engine, such as output and drivability. Has no effect. The present invention is not limited to the embodiment described above.
For example, the predetermined phase set to facilitate the feedback control is not limited to twice, and may be set within a range that hardly affects the performance of the internal combustion engine, such as output and drivability. Further, in the above-described embodiment, the present invention is applied to the variable valve timing mechanism that can make the valve timing of the intake valve variable, but the same effect can be obtained by applying the present invention to the one that makes the valve timing of the exhaust valve variable. is there. In addition, the present invention is not limited to the illustrated example, and various modifications can be made without departing from the gist of the invention.

[0036]

As described in detail above, according to the present invention,
Conventionally, in a predetermined operating state in which the switching control valve has been continuously opened in the direction of retarding, the target valve timing is set to a timing advanced by a predetermined phase from the most retarded timing, and feedback control is performed. The situation in which the control valve keeps opening can be avoided, and the leak amount can be reduced due to the decrease in the hydraulic fluid pressure in the variable valve timing mechanism. Therefore, it is possible to reduce the amount of hydraulic fluid supplied to the valve timing mechanism. Become. Therefore, it is possible to solve the problem that the lubrication of the crank or the like is hindered, the system hydraulic pressure is reduced, and the blow-by function is impaired by a large amount of hydraulic fluid flowing into the blow-by passage.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing one embodiment of the present invention.

FIG. 2 is a schematic diagram showing an intake / exhaust-side camshaft portion of the embodiment.

FIG. 3 is a schematic sectional view mainly showing a variable valve timing mechanism of the embodiment.

FIG. 4 is a partial sectional view taken along line AA in FIG. 3;

FIG. 5 is a partial sectional view taken along line BB in FIG. 3;

FIG. 6 is an operation state explanatory diagram for showing a predetermined operation state of the engine.

FIG. 7 is a flowchart showing a target valve timing calculation routine in the embodiment.

FIG. 8 is a flowchart showing an OCV control routine in the embodiment.

FIG. 9 is a correlation diagram showing a correlation between an OCV spool position and a supply hydraulic fluid amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine (Engine) 2 ... Intake valve 3 ... Exhaust valve 4 ... Variable valve timing mechanism 19 ... Switching control valve (OCV) VT ... Actual valve timing VTT ... Target valve timing P: hydraulic pressure source (pump) AR: predetermined operating state

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) NE11 PA07Z PE01Z PE03Z PE05Z PE10A PE10Z

Claims (1)

[Claims] A switching control valve capable of changing a flow rate and a direction of a hydraulic fluid supplied from an external hydraulic pressure source is controlled to freely change a valve timing for opening and closing at least one of an exhaust valve and an intake valve. The present invention is applied to a hydraulic variable valve timing mechanism of an internal combustion engine, wherein when the internal combustion engine is in a predetermined operation state such as a high rotation state, the target valve timing is set to a predetermined value from the most retarded timing. A valve timing control method comprising: setting a timing at which the phase is advanced, and performing feedback control of the switching control valve so that the actual valve timing becomes the set target valve timing.