JP2003065088A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accurate feedback control for achieving a target rotating phase of a camshaft by positively preventing an excessive controlled amount from being set in a valve timing control device for an internal combustion engine for controlling a valve timing by varying the rotating phase of the camshaft. SOLUTION: While the target rotating phase of a camshaft 11 remains stabilized (constant), an integrated value is calculated of a difference between the target rotating phase of the camshaft set in accordance with an engine operating condition and an actual rotating phase detected with a cam sensor 15. A calculation is then performed including the calculated integrated value to find a feedback correction amount, thereby providing a feedback control of the rotating phase of the camshaft. When the target rotating phase of the camshaft is varied, on the other hand, it is prohibited to calculate the integrated value for calculating the feedback correction amount for a predetermined period of time after the target rotating phase has varied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for an internal combustion engine, which controls a valve timing by changing a rotational phase of a camshaft with respect to a crankshaft, and accurately sets the rotational phase of the camshaft to a target rotational phase. Feedback control technology.

[0002]

2. Description of the Related Art Conventionally, there is known a valve timing control device for an internal combustion engine which controls the valve timing of an intake valve or an exhaust valve by changing the rotational phase of a cam shaft with respect to a crank shaft. In this type of valve timing control device, feedback control is generally performed so that the detected actual rotation phase of the camshaft becomes a target rotation phase set according to the operating state of the engine.

Specifically, a feedback correction amount is calculated by proportional-plus-integral (PI) control or sliding mode control, and a reference control amount to be set is corrected by the calculated feedback correction amount to control the camshaft rotation phase. Is set. For example, in the valve timing control device disclosed in Japanese Patent Application Laid-Open No. 11-2140, the proportional operation amount and the integral operation amount are calculated based on the difference between the target rotation phase and the actual rotation phase (hereinafter referred to as error amount). The output control amount is corrected based on the proportional operation amount and the integral operation amount.

Even when the sliding mode control is used, the state equation is expanded so that the integrated value of the error amount is included in the linear term, and the feedback correction amount is calculated so that the steady-state deviation becomes zero.

[0005]

By the way, there is a response delay in the valve timing control. Therefore, immediately after the target rotational phase of the camshaft changes, the actual rotational phase has not changed yet. Therefore, when the feedback correction amount is calculated using the integrated value of the error amount as in the conventional case, Therefore, the feedback control amount corrected and set by is excessively large, which may cause overshoot or hunting, and in the worst case, may lead to divergence.

The present invention has been made in view of the above circumstances, and provides a valve timing control device for an internal combustion engine, which surely prevents an excessive control amount from being set, and is excellent in convergence stability. The purpose is to

[0007]

Therefore, the invention according to claim 1 is a valve timing control device for an internal combustion engine, which controls the opening / closing timing of an intake valve or an exhaust valve by changing the rotational phase of a camshaft with respect to a crankshaft. ,
The cam is calculated by calculating an integral value of a difference between a target rotation phase of the cam shaft and an actual rotation phase set according to an operating state of the engine, and calculating a feedback correction amount by a calculation process including the calculated integral value. While feedback controlling the rotational phase of the shaft, when the target rotational phase of the cam shaft changes, the calculation of the integrated value is prohibited for a predetermined period after the change of the target rotational phase, and the integrated value is removed. It is characterized in that the feedback correction amount is calculated by arithmetic processing.

The invention according to claim 2 is characterized in that, when the calculation of the integral value is prohibited, the feedback correction amount is calculated using the integral value calculated immediately before the change of the target rotational phase. The invention according to claim 3 is characterized in that the rotational phase of the cam shaft is feedback-controlled by calculating a feedback correction amount by sliding mode control.

The invention according to claim 4 is characterized in that the dead time included in the rotational phase control of the cam shaft is estimated and the dead time is set as the predetermined time. Claim 5
In the invention according to claim 1, the rotation phase of the camshaft is controlled by selectively controlling supply and discharge of hydraulic pressure to and from a hydraulic actuator, and the predetermined period is based on a rotational speed of the engine. It is set by setting.

[0010]

According to the first aspect of the invention, when the target rotational phase of the camshaft is stable (constant), the difference (deviation between the target rotational phase and the actual rotational phase depending on the operating state of the engine). )
Since the feedback correction amount is calculated by calculating the integrated value of and the calculation processing including the calculated integrated value, high convergence can be ensured.

On the other hand, immediately after the target rotational phase of the camshaft changes, the rotational phase of the camshaft that is actually output has a response delay. Therefore, during the predetermined period, the calculation of the integral value in the calculation of the feedback correction amount is performed. Is excluded, and the feedback correction amount is calculated by excluding the integral value (integral element) and performing arithmetic processing by another element such as a proportional element or a derivative element. As a result, it is possible to prevent excessive feedback correction amount calculation (and thus excessive feedback control amount calculation) and prevent overshoot and hunting.

According to the second aspect of the present invention, immediately after the change of the target rotation phase of the cam shaft, the feedback correction amount is calculated by using the integrated value of the difference between the target rotation phase calculated immediately before and the actual rotation phase. Since it is calculated, it is possible to prevent overshoot and hunting while ensuring high convergence. According to the invention of claim 3, even when the rotation phase of the cam shaft is feedback-controlled by the sliding mode control, immediately after the change of the cam shaft target rotation phase, the target rotation phase included in the linear term and the nonlinear term is included. By prohibiting the calculation of the integrated value of the difference between the actual rotation phase and the actual rotation phase, the feedback correction amount can be calculated appropriately.

According to the fourth aspect of the present invention, since the dead time included in the rotational phase control of the cam shaft is estimated and the dead time is set as the predetermined period, the actual rotational phase of the cam shaft changes. Up to, the calculation of the integral value of the difference between the target rotation phase and the actual rotation phase in the calculation of the feedback correction amount is prohibited, and the excessive feedback control amount is calculated, and it is possible to effectively prevent the occurrence of overshoot and hunting. .

Here, the dead time is, for example, in a hydraulic valve timing control device, the actual rotation of the camshaft after the target rotation phase of the camshaft set according to the operating state of the engine changes. This is the time until the phase changes and this is detected. In the electromagnetic valve timing control device, the time until the camshaft torque matches the VTC conversion direction and the time when the camshaft rotational position is detected. Say time

According to the fifth aspect of the present invention, in the case of the hydraulic valve timing control device, the dead time for changing the hydraulic pressure also changes according to the rotational speed of the engine. Therefore, based on the rotational speed of the engine, A period during which the calculation of the integrated value is prohibited is set. Thereby, the period (the predetermined period) in which the calculation of the integral value is prohibited can be appropriately set according to the operating state.

If a table or the like is created in advance, the predetermined period can be set more easily.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an engine showing an embodiment of the present invention. In FIG. 1, an intake passage 2 of an engine 1 is provided with an air flow meter 3 for detecting an intake air flow rate Qa.
control a.

Each cylinder of the engine 1 is provided with a fuel injection valve 6 for injecting fuel into the combustion chamber 5, and a spark plug 7 for performing spark ignition in the combustion chamber 5, which is sucked in through an intake valve 8. Fuel is injected from the fuel injection valve 6 to the generated air to form a mixture, which is compressed in the combustion chamber 5 and ignited by spark ignition by a spark plug 7. Exhaust gas of the engine 1 is discharged from the combustion chamber 5 to the exhaust passage 10 via an exhaust valve 9 and is discharged to the atmosphere via an exhaust purification catalyst and a muffler (not shown).

The intake valve 8 and the exhaust valve 9 are driven to open and close by cams provided on the intake side cam shaft 11 and the outside air side cam shaft 12, respectively. In the intake side camshaft 11,
A variable valve timing mechanism (VTC) 13 is provided to control the opening / closing timing of the intake valve 8 by changing the rotational phase of the cam shaft with respect to the crank shaft.

The C / U (control unit) 20 is
A microcomputer is built-in to perform control of the fuel injection amount and fuel injection timing by the fuel injection valve 6, ignition timing control by the spark plug 7, air-fuel ratio control, etc. based on various input detection signals. There is. Also, C / U20
Is based on the detection signals from the crank angle sensor 14 and the cam sensor 15, and the intake side camshaft 1 with respect to the crankshaft.
The opening / closing timing of the intake valve 8 is detected by detecting the respective rotation phases of No. 1 and the target rotation phase (target angle) of the intake side camshaft 11 is determined based on the information such as the engine load and the engine rotation speed Ne. It is set to control the opening / closing timing of the intake valve 8.

Here, the variable valve timing mechanism (VT
The structure of C) 13 will be described. The VTC 13 is shown in FIG.
As shown in FIG. 5, a cam sprocket 51 (timing sprocket) that is rotationally driven by a crankshaft (not shown) via a timing chain, and an intake side camshaft 11
A rotary member 53 fixed to the end of the cam sprocket 51 and rotatably housed in the cam sprocket 51, and a hydraulic circuit 54 for rotating the rotary member 53 relative to the cam sprocket 51.
And a lock mechanism 60 for selectively locking the relative rotational position of the cam sprocket 51 and the rotary member 53 at a predetermined position.
It has and.

The cam sprocket 51 has a rotating portion (not shown) having teeth on the outer periphery thereof with which a timing chain (or a timing belt) meshes, and is arranged in front of the rotating portion so that the rotating member 53 can rotate. It is configured to include a housing 56 that accommodates it, and a front cover and a rear cover (not shown) that close the front and rear openings of the housing 56.

The housing 56 has a cylindrical shape with openings formed at the front and rear ends thereof, and has an inner peripheral surface (housing 56
(4) Along with the axial direction, four partition walls 63 having a trapezoidal cross section are provided at 90 ° intervals. Rotating member 5
3 is fixed to the front end portion of the intake-side camshaft 11, and four vanes 78a, 78b, 78c, 78d (in order, first, second, and
Third and fourth vanes) are provided.

Incidentally, the first to fourth vanes 78a to 78d.
As shown in the drawing, each has a substantially trapezoidal cross-sectional shape and is disposed in a recess formed between the partition walls 63. As a result, the first to fourth vanes 78a to 78d each define a recess in the front and rear in the rotational direction, and the recesses in the front and rear define the advance side hydraulic chamber 82 and the retard side hydraulic chamber 83, respectively. .

The lock mechanism 60 has a lock pin 84 that engages (engages) with an engaging hole (not shown) at the rotational position (reference operation state) of the rotating member 53 on the maximum retard side.
The hydraulic circuit 54 has two systems of a first hydraulic passage 91 for supplying and discharging hydraulic pressure to and from the advance side hydraulic chamber 82 and a second hydraulic passage 92 for supplying and discharging hydraulic pressure to and from the retard side hydraulic chamber 83. A hydraulic passage is provided, and the supply passage 9 is provided in the two hydraulic passages 91 and 92.
3 and the drain passages 94a and 94b are connected to each other via an electromagnetic switching valve 95 for passage switching.

The supply passage 93 is provided with an engine-driven oil pump 97 for pumping the oil in the oil pan 96, and the drain passages 94a and 94b have their downstream ends communicating with the oil pan 96. The first hydraulic passages 91 are connected to four branch passages 91d that are formed substantially radially inside the base portion 77 of the rotary member 53 and communicate with the respective advance-side hydraulic chambers 82, and the second hydraulic passages 92 are It is connected to four oil holes 92d that open in each retard angle side hydraulic chamber 83.

The electromagnetic switching valve 95 has an internal spool valve element for the first and second hydraulic passages 91 and 92 and the supply passage 9.
3 or the communication with the drain passages 94a and 94b is switched and controlled. The electromagnetic switching valve 95 is driven by the control unit (C / U) 20 controlling the amount of electricity to the electromagnetic actuator 99 based on the duty control signal on which the dither signal is superimposed.

For example, when a control signal (OFF signal) with a duty ratio of 0% is output to the electromagnetic actuator 99, the hydraulic oil pumped from the oil pump 97 passes through the second hydraulic passage 92 and enters the retard angle side hydraulic chamber 83. While being supplied, the hydraulic oil in the advance-side hydraulic chamber 82 passes through the first hydraulic passage 91 and is discharged from the first drain passage 94a into the oil pan 96.

As a result, the internal pressure of the retard side hydraulic chamber 83 is high, the internal pressure of the advance side hydraulic chamber 82 is low, and the rotary member 53 is
Rotates to the retard side through the first to fourth vanes 78a to 78b to reach the maximum retard position. On the other hand, when a control signal (ON signal) with a duty ratio of 100% is output to the electromagnetic actuator 99, hydraulic oil is supplied into the advance side hydraulic chamber 82 through the first hydraulic passage 91 and the retard side hydraulic chamber is supplied. The hydraulic oil in 83 is the second hydraulic passage 92 and the second drain passage 94b.
Through the oil pan 96 to the retard side hydraulic chamber 8
The internal pressure of 3 becomes low.

As a result, the rotating member 53 rotates to the advance side via the first to fourth vanes 78a to 78d and reaches the maximum advance position. The C / U 20 detects the rotational phase (advance amount) detected value of the cam sprocket 51 and the intake side cam shaft,
A feedback correction amount UDTY for matching the target value (target advance angle amount) set according to the operating state is set by sliding mode control, and a predetermined base duty ratio BASEDTY (neutral control value) and feedback correction amount UDTY are set. The final duty ratio VTCDTY is set as the result of the addition, and a control signal of the duty ratio VTCDTY is output to the electromagnetic actuator 99.

That is, when it is necessary to change the rotation phase in the retard direction, the feedback correction amount U
The duty ratio is reduced by DTY, and the oil pump 9
7 is supplied to the retard side hydraulic chamber 83, and the hydraulic oil in the advance side hydraulic chamber 82 is supplied to the oil pan 9
6 will be discharged. On the contrary, when it is necessary to change the rotation phase in the advance direction, the duty ratio is increased by the feedback correction amount UDTY,
The hydraulic oil is supplied to the advance side hydraulic chamber 82, and the hydraulic oil inside the retard side hydraulic chamber 83 is discharged to the oil pan 96.

When the rotational phase is kept in the current state, the absolute value of the feedback correction amount UDTY is reduced, so that the base duty ratio BASEDTY.
The duty ratio is controlled to return to the vicinity. Here, the feedback correction amount UDTY is calculated as follows by the sliding mode control.

1. Calculation of mathematical model In sliding mode control, the parameters of the controller are determined by the mathematical model to be controlled.
First, the mathematical model of VTC is calculated. In the present embodiment, system identification is performed using the control duty as input and the actual rotation angle (real angle) of the VTC as output, and the quadratic delay type transfer function shown in Expression (1) is obtained.

G (s) = b / (s ² + a ₁ · s + a ₀ ) ... (1) where a ₀ and a ₁ are output parameters of the controlled object (VTC). 2. Calculation of state equation From the transfer function G (s), the control duty is u, VT
When the real angle of C is x, the differential equation of VTC is given by equation (2).

[0035]

[Equation 1]

Here, the VTC real angle is x1, the differential value of x1 is x2, and the equation of state is expressed by equation (3),

[0037]

[Equation 2]

Further, VT is used as the state variable of the above state equation.
The integral value hat x3 of the C actual angle x, the target angle r, and the deviation (error amount) is expanded to be included in the linear term (equation (4)).

[0039]

[Equation 3]

3. The design sliding mode control of the switching function σ depends on the system state.
Since the feedback gain is switched, the switching function σ is defined as in equation (5).

[0041]

[Equation 4]

However, α ₁ and α ₃ are parameters for obtaining the inclination on the phase plane (note that α ₂ = Im is set to reduce the dimension of the system). Since the switching function σ = 0 can be expressed in the sliding mode, the equation (6) is obtained.

[0043]

[Equation 5]

Here, the equation (4) is obtained by using the equation (6).
Since it can be expressed as follows,

[0045]

[Equation 6]

The following low-dimensional system can be obtained.

[0047]

[Equation 7]

This represents the dynamic characteristics when the system state is restricted to the hyperplane, that is, when the system is in the sliding mode. Where d (σ) /
When formula (5) is expanded from dt = S · d (x) / dt,
It becomes like Formula (10).

[0049]

[Equation 8]

When the state of the system is in the hyperplane, the equation (10) = 0, so this is transformed to the linear term u (= Ue).
q) is obtained (equation (11)).

[0051]

[Equation 9]

Here, in the hydraulic valve timing control device, since the control duty corresponding to the deviation between the actual angle x1 and the target angle r is given to the electromagnetic actuator 99, in this embodiment, as shown in the block diagram of FIG. And the actual angle x1 is the deviation hat x1 between the actual angle x1 and the target angle r.
(= X1-r), the differential value x2 of x1 is replaced with the differential value hat x2 of the hat x1.

That is, as shown in FIG. 3, the target angle r
The linear term manipulated variable Ueq is calculated from the error amount (control deviation) hat x1 (= x1-r), which is the deviation between the actual angle x1 and the actual angle x1, and the integrated value hat x3 of the error amount hat x1. Also,
A switching function σ is calculated from the error amount (hat x1), the integrated value (hat x3) and the differential value (hat x2) of the error amount.

Then, using the switching function σ, the following equation (1
The non-linear manipulated variable Unl is calculated according to 2).

[0055]

[Equation 10]

However, K is a nonlinear term gain, and δ is a chattering prevention coefficient. The linear term manipulated variable Ueq moves the system state toward a target value along the switching line (S = 0), and the nonlinear term manipulated variable Unl changes the state (S =).
0), and works to restrain on the switching line (S = 0). As a result, the system state is directed from the initial state to the switching line (S = 0) on the phase plane, and the switching line (S =
When the system state gets on (0), it reaches the origin (target value) while slipping while being restrained on the switching line (S = 0).

Then, the linear term manipulated variable Ueq and the nonlinear term manipulated variable Unl are added to calculate a feedback correction amount UDTY, and the feedback correction amount UDTY is calculated.
Is a base duty ratio BA corresponding to the dead zone neutral position
It is added to SEDTY and the addition result is output as the final duty ratio VTCDTY. In this way, the feedback correction amount is calculated by the sliding mode control, and the feedback gain is switched so as to guide the state of the system on the preset switching line S = 0. Therefore, the dead band of the electromagnetic switching valve 95 is changed. Is less likely to be affected by disturbances such as variations in oil temperature, oil temperature, and oil pressure, and highly robust control can be performed.

Here, in the present embodiment, the target rotational phase (target angle) of the intake side camshaft 11 is changed in order to prevent overshoot and hunting from occurring due to calculation and output of an excessive control amount. After that, the actual rotation phase changes, and until the cam sensor 15 detects it, the calculation of the integrated value (that is, the hat x3) of the error amount (hat x1) is prohibited.

That is, until the dead time included in the rotational phase control of the intake camshaft 11 elapses, the integrated value hat x3 of the error amount (hat x1) is not calculated and immediately before the target angle changes. Using the calculated integrated value of the error amount (previous value) as it is, the duty ratio VTCDTY
Is calculated. Such control will be described with reference to the flowchart shown in FIG.

In FIG. 4, in step 1, the engine speed Ne, the target angle r of the intake camshaft 11 and the actual angle x1 are read. In step 2, it is determined whether the target angle r has changed. If the target angle r has changed, the process proceeds to step 3. In step 3, the dead time is calculated.

Here, the dead time means the time from the input to the controlled object until the effect appears in the output. In the present embodiment, since the hydraulic variable phase mechanism 14 is used, After the duty is applied to the electromagnetic actuator 99, the spool valve element moves to secure the oil passage, and the cam sensor 15 operates the actual intake-side camshaft 11 during the time until the oil flows through the oil passage into the hydraulic chamber to operate. The time until the rotation angle (position) is detected is added.

In the hydraulic valve timing control device, the oil pressure changes depending on the engine speed, and the dead time also changes. Therefore, for example, a table shown in FIG. And ask. In step 4, the dead time calculated in step 3 is divided by the feedback control cycle (cycle for each JOB),
Feedback control JOB number dm in which the integrated value hat x3 of the error amount (x1-r) is not calculated (inhibited)
To calculate.

Dm = (dead time) / (F / B control 1 JOB cycle) In step 5, the calculation of the integrated value hat x3 of the error amount is prohibited.
DTY is calculated using the value immediately before the target angle changes (the previous integrated value hat x3 (-1)). In Step 7, the integrated value hat x3 of the error amount is not calculated.
Decrement the B number dm and return.

If it is determined in step 2 that the target angle has not changed, the process proceeds to step 8 and it is determined whether or not the JOB number dm is greater than zero. If dm is greater than 0, the dead time has not yet elapsed, so the routine proceeds to step 5, where the calculation of the integrated value hat x3 of the error amount is prohibited, and at step 6, the feedback correction amount UDTY.
Is calculated, and dm is decremented in step 7.

If dm is 0 or less, the dead time has already elapsed, so the process proceeds to step 9 to restart the calculation of the integrated value x3 of the error amount and use the integrated value of the error amount calculated in step 10. The feedback correction amount UDTY is calculated. As described above, when feedback control of the rotational phase of the cam shaft is performed, the calculation of the integrated value hat x3 of the error amount is prohibited until the dead time elapses, so that an excessive feedback correction amount is prevented from being calculated. However, the occurrence of overshoot and hunting can be suppressed.

Although the control of the valve timing of the intake valve 8 has been described above, the control of the valve timing of the exhaust valve 9 may be used. Further, the invention is not limited to the VTC using the vane type hydraulic actuator, but may be one that changes the rotational phase of the cam shaft by converting linear motion into rotational motion using a linear hydraulic actuator, It is not limited to the sliding mode control.

Further, it is not limited to the hydraulic VTC, but may be an electromagnetic VTC. In the case of an electromagnetic variable valve timing mechanism, the time until the camshaft torque matches the VTC conversion direction and the time until the rotational position of the camshaft is detected are dead time.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment according to the present invention.

FIG. 2 is a schematic diagram of a vane type variable valve timing mechanism according to an embodiment of the present invention.

FIG. 3 is a block diagram showing calculation of a feedback correction amount using sliding mode control in camshaft rotation phase control of the present embodiment.

FIG. 4 is a flowchart showing camshaft rotation phase control in this embodiment.

FIG. 5 is a diagram (an example of a table) showing the relationship between the rotational speed of the engine and the dead time.

[Explanation of symbols]

1 engine 2 Intake passage 3 Air flow meter 4 Throttle valve 8 intake valve 9 Exhaust valve 10 exhaust passage 11 Intake side camshaft 12 Exhaust side camshaft 13 Variable valve timing mechanism 14 Crank angle sensor 15 Cam sensor 20 control unit

Continued front page    F-term (reference) 3G018 BA33 CA11 CA12 CA13 CA18                       DA34 DA73 EA02 EA11 EA16                       EA22 EA31 EA32 FA01 FA07                       GA00 GA02 GA03 GA38                 3G092 AA11 DA08 DA10 EA03 EA04                       EA18 EB03 EB09 EC00 EC01                       EC02 FA05 FA07 FA09 HA01Z                       HA06Z HE00X HE01Z HE03Z                 5H004 GA03 GA06 GB12 HB07 KA22                       KA74 LB08 MA36

Claims (5)

[Claims] 1. A valve timing control device for an internal combustion engine, which controls the opening / closing timing of an intake valve or an exhaust valve by changing the rotational phase of a camshaft relative to a crankshaft, wherein the camshaft is set according to the operating state of the engine. The integrated value of the difference between the target rotational phase and the actual rotational phase is calculated, and the feedback correction amount is calculated by the calculation process including the calculated integrated value to feedback control the rotational phase of the cam shaft, while the cam shaft is controlled. When the target rotation phase has changed, the calculation of the integral value is prohibited for a predetermined period after the change of the target rotation phase, and the feedback correction amount is calculated by a calculation process excluding the integral value. Valve timing control device for internal combustion engine. 2. The internal combustion engine according to claim 1, wherein when the calculation of the integral value is prohibited, the feedback correction amount is calculated using the integral value calculated immediately before the change of the target rotational phase. Valve timing control device. 3. The valve timing control device for an internal combustion engine according to claim 1, wherein the rotational phase of the camshaft is feedback-controlled by calculating a feedback correction amount by sliding mode control. 4. The dead time included in the rotational phase control of the cam shaft is estimated, and the dead time is set as the predetermined time, according to any one of claims 1 to 3.
5. A valve timing control device for an internal combustion engine according to claim 3. 5. A rotation phase of the cam shaft is controlled by selectively controlling supply and discharge of hydraulic pressure to and from a hydraulic actuator by a switching valve, and the predetermined period is based on a rotational speed of an engine. The valve timing control device for an internal combustion engine according to claim 1, wherein the valve timing control device is set according to any one of claims 1 to 3.