JPH07229410A - Valve timing control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To continue a stable control even when battery voltage is fluctuated. CONSTITUTION:A variable valve timing actuator (VVT) 133 is situated in an intial position by a spring when a control valve 134 for supplying a hydraulic pressure which is a driving force is fully closed. When battery voltage becomes lower than a lower limit voltage, the control valve 134 is fully closed to stop feedback control, and the VVT 133 is kept in the initial position. When the phase difference determined from the operating state is a prescribed phase difference or more when the battery voltage is returned, the return to the feedback control is prohibited to prevent the generation of a torque shock.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for an internal combustion engine, and more particularly to a valve timing control device for an internal combustion engine capable of preventing abnormal valve timing control when the power supply voltage drops. .

[0002]

2. Description of the Related Art A valve timing control device is known which can control the opening / closing timing of an engine valve according to the operating state of an internal combustion engine to increase the output or improve the fuel consumption. In this valve timing control device, a VVT actuator is installed between the timing pulley installed at the tip of the cam shaft and the cam shaft in order to change the phase difference. It was common to apply stepping motors powered by.

However, in the valve timing control device driven by the stepping motor, the valve speed cannot be accurately controlled because the rotational speed changes between the forward rotation and the reverse rotation. In order to solve this problem, the present applicant has proposed that when the battery voltage drops below a predetermined threshold voltage, the feedback control is stopped and the valve timing is fixed to a predetermined value (Japanese Patent Laid-Open Publication No. Sho. 59-11322).

[0004]

However, when the battery voltage drops, fixing a predetermined valve timing by a stepping motor that receives power from the battery not only causes overdischarge of the battery but also causes It may not rotate to the position.

Further, when the battery voltage is restored, a torque shock may occur due to a shift to the phase difference determined corresponding to the operating state immediately. The present invention has been made in view of the above problems, and an object thereof is to provide a valve timing control device for an internal combustion engine that can continue stable control even when the battery voltage changes.

[0006]

A valve timing control system for an internal combustion engine according to a first aspect of the present invention includes a state quantity detecting means for detecting a state quantity representing an internal combustion engine operating state and an actual phase difference between a camshaft and a crankshaft. And a phase difference detection means for detecting, and an operation signal for making the actual phase difference detected by the phase difference detection means coincide with the target phase difference determined based on the state quantity detected by the state quantity detection means. A ring gear and a ring gear having operation signal calculating means for calculating and biasing means for forming biased teeth on at least one of the outer circumference and the inner circumference to bias the operation signal calculating means to an initial position when the operation signal calculating means is in a disconnected state. A timing pulley that is fitted to one tooth of the ring gear and is driven by the crankshaft, and a cap and oil that is fitted to the other tooth of the ring gear and is joined to the camshaft. By means of a phase difference changing means composed of a hydraulic pressure supplying means for moving the ring gear from the initial position to a position according to the operation signal calculated by the operation signal calculating means in the rotation axis direction, and a voltage for detecting the voltage of the DC power supply. The detection means and the control interruption means for turning off the operation signal calculation means when the voltage detected by the voltage detection means becomes equal to or lower than a predetermined lower limit voltage.

A valve timing control device for an internal combustion engine according to a second aspect of the present invention includes a control returning means for returning control by the operation signal calculating means when the voltage detected by the voltage detecting means becomes equal to or higher than a predetermined return voltage. When the deviation between the actual phase difference detected by the phase difference detecting means and the target phase difference determined based on the state quantity detected by the state quantity detecting means is a predetermined threshold deviation or more, the control restoring means is used. And a return prohibition unit that prohibits return.

A valve timing control system for an internal combustion engine according to a third aspect of the present invention includes a state quantity detecting means for detecting a state quantity representing an operating state of the internal combustion engine and a unit for detecting an actual phase difference between the camshaft and the crankshaft. A pulse for calculating the duty ratio of the pulse signal in order to match the actual phase difference detected by the phase difference detection means with the target phase difference determined based on the state quantity detected by the state quantity detection means. A signal calculation means, a voltage detection means for detecting the voltage of the DC power supply, a maximum duty ratio calculation means for calculating the maximum duty ratio corresponding to the voltage detected by the voltage detection means, and a pulse calculated by the pulse signal calculation means. A duty ratio limiting means for limiting the duty ratio of the signal to the maximum duty ratio calculated by the maximum duty ratio calculating means; A signal converting means for converting the pulse signal limited by the duty ratio limiting means into a direct current signal according to the duty ratio, and a pulse signal computing means in which at least one of the outer circumference and the inner circumference is formed with teeth having oblique teeth. A timing gear driven by a crankshaft and a ring gear having a biasing means for biasing to the initial position when in the disconnected state and a timing pulley driven by the crankshaft and the other tooth of the ring gear are fitted to the camshaft. Phase difference changing means including a cap to be coupled and a hydraulic pressure supply means for moving the ring gear from the initial position to the position according to the DC signal converted by the signal converting means in the rotation axis direction by the hydraulic pressure. .

A valve timing control apparatus for an internal combustion engine according to a fourth aspect of the present invention includes a state quantity detecting means for detecting a state quantity representing an operating state of the internal combustion engine and a unit for detecting an actual phase difference between the camshaft and the crankshaft. A pulse for calculating the duty ratio of the pulse signal in order to match the actual phase difference detected by the phase difference detection means with the target phase difference determined based on the state quantity detected by the state quantity detection means. Signal calculation means, voltage detection means for detecting the voltage of the DC power supply, duty ratio correction means for correcting the duty ratio of the pulse signal calculated by the pulse signal calculation means according to the voltage detected by the voltage detection means, At least one of the outer circumference and the inner circumference is a tooth having at least one beveled tooth and is biased to the initial position when the pulse signal calculation means is in the disconnected state. A ring gear having biasing means and a timing pulley that is fitted to one tooth of the ring gear and driven by the crankshaft, and a cap that is fitted to the other tooth of the ring gear and is joined to the camshaft And a phase difference changing unit including a hydraulic pressure supply unit that moves in the rotation axis direction to a position according to the pulse signal corrected by the duty ratio correction unit.

[0010]

In the valve timing control device for an internal combustion engine according to the first aspect of the present invention, when the power supply voltage drops below the lower limit voltage, the control valve is fully closed and the valve timing is mechanically determined at the initial position of VVT. Fix the timing to be done. In the valve timing control device for the internal combustion engine according to the second aspect of the present invention, the return to the feedback control is prohibited if the target phase difference is large when the voltage returns to the return voltage or higher.

In the valve timing control device for the internal combustion engine according to the third aspect of the invention, the duty ratio of the pulse output from the control device when the solenoid valve is driven via the linear solenoid IC depends on the power supply voltage. Limit within the maximum duty ratio. In the valve timing control device for an internal combustion engine according to the fourth aspect, the duty ratio of the pulse output from the control device when the solenoid valve is driven without the linear solenoid IC is corrected according to the power supply voltage. .

[0012]

1 is a block diagram of a valve timing control system for an internal combustion engine according to the present invention, in which a cylinder 111 of an internal combustion engine is provided with a piston 111 slidably up and down.
The upper part of the piston 111 is the combustion chamber 12. The piston 111 is connected to the crankshaft 113 via a connecting rod 112.

A magnetic material 114 is provided on the crankshaft 113.
Is embedded, and a reference pulse is output from the first magnetic sensor 115 arranged close to the crankshaft 213. A timing pulley 116 is installed at the tip of the crankshaft 113. An intake pipe 121 and an exhaust pipe 122 are connected to the combustion chamber 12,
A throttle valve 123 for adjusting the amount of intake air is installed upstream of the intake pipe 121. The opening of the throttle valve 123 is detected by the opening sensor 124.

An intake valve 13 is provided at a connection port between the combustion chamber 12 and the intake pipe 121, and a fuel injection valve 12 is provided immediately upstream of the intake valve 13.
5 is installed. An exhaust valve 14 is installed at the connection port between the combustion chamber 12 and the exhaust pipe 122. The intake valve 13 and the exhaust valve 14 are driven by cams (not shown) attached to the cam shafts 131 and 141.

Timing pulleys 132 and 142 are installed at the tips of the camshafts 131 and 141, and the timing pulley 1 installed on the crankshaft 113.
16 and the timing belt 117.
Further, the intake valve camshaft 131 and the timing pulley 13
A variable valve timing actuator (hereinafter referred to as VVT) 133 is installed between the two and the variable valve timing actuator 133 to change the rotational phase of the intake valve camshaft 131 with respect to the crankshaft 113.

The VVT 133 is driven by hydraulic pressure supplied from a hydraulic pressure source (not shown), and the rotational phase is controlled by controlling the opening degree of the control valve 134. A magnetic material 135 is embedded in the intake valve camshaft 131, and a pulse is output from the second magnetic sensor 136 arranged in close proximity to the intake valve camshaft 131 every one rotation.

A distributor 15 is attached to the internal combustion engine 2, and a pulse is generated by the first rotation speed sensor 151 for every two rotations of the internal combustion engine, and a 30 ° cam angle of the internal combustion engine is generated by the second rotation speed sensor 152. One pulse is output for each. The internal combustion engine control device 16 is a microcomputer system, which is composed of a CPU 162, a memory 163, an input interface 164, and an output interface 165 centering on a bus 161.

The input interface 164 includes a first magnetic sensor 115, an opening sensor 124, a second magnetic sensor 136, a first rotation speed sensor 151, a second rotation speed sensor 152, a cooling water temperature sensor 119 and intake air. The temperature sensor 126 is connected, and each detection signal is taken in by the internal combustion engine controller 16. Output interface 16
A fuel injection valve 125 and a control valve 134 are connected to 5 and are controlled based on the calculation result of the internal combustion engine control device 16.

FIG. 2 is a sectional view of the VVT 133, which is hydraulically driven. The hydraulic oil stored in the oil pan 201 is pressurized by the pump 202, filtered by the filter 203, the flow rate is controlled by the control valve 134, and then supplied to the VVT 133. A tooth 204a is provided inside the cap 204 attached to the tip of the intake valve camshaft 131, and the timing pulley 13 is arranged coaxially with the intake camshaft.
The teeth 132a are also formed on the second side. At least one of the teeth 204a and 132a is an oblique tooth.

Inside the ring gear 205, a tooth 205 is fitted with a tooth 132a formed on the timing pulley 132.
a has teeth 2 formed on the inside of the cap 204 on the outside.
Teeth 205b are formed to mate with 04a. The ring gear 205 includes a ring gear 205 and a timing pulley 132.
A cap 204 by means of a spring 206 arranged between
Biased to the side.

The hydraulic oil that has flowed out of the control valve 134 is supplied to the pressurizing chamber 207 formed between the cap 204 and the ring gear 205 via the flow path, and displaces the ring gear 205 in the axial direction of the cam shaft 131. Since at least one of the two sets of mutually fitting teeth is formed as an oblique tooth, when the ring gear 205 is displaced in the axial direction, the camshaft is twisted to adjust the phase of the camshaft with respect to the crankshaft. It becomes possible to do.

When the control valve 134 is fully closed and the supply of hydraulic oil is stopped, the ring gear 205 is positioned at a predetermined position (initial position) on the cap 204 side by the urging force of the spring 206. FIG. 3 is a flow chart of a first valve timing control routine executed by the control device 16 in the first aspect of the present invention. In step 31, a battery (not shown) is used.
The voltage V of is read.

At step 32, it is judged if the voltage V is equal to or higher than a predetermined lower limit voltage V _L. Step 3
If the affirmative determination is made in 2, it is determined that the normal valve timing control is possible, the feedback control process of step 33 is executed, the opening α of the control valve 134 is determined, and the step 3
Go to 5.

If a negative determination is made in step 33, it is determined that the valve timing control cannot be normally executed, and the process proceeds to step 34, where the opening α of the control valve 134 is set to "0" which corresponds to full closing, and step 35 is performed. Proceed to. Step 3
In step 5, the opening α of the control valve 134 is output, and this routine ends. Therefore, when the battery voltage V drops below the lower limit voltage V _L (for example, 8 V), the opening degree α of the control valve 134 becomes “0”, the supply of hydraulic oil to the VVT 133 is cut off, and the VVT 133 is positioned at the initial position.

FIG. 4 is a detailed flowchart of the feedback control process executed in step 33. The first pulse θ _c detected by the first magnetic sensor 115 in step 331 and the second pulse detected by the second magnetic sensor 136. Done second
Of the pulse θ _i , the internal combustion engine rotational speed N _e detected by the second rotational speed sensor 151, and the throttle valve opening sensor 12
The throttle valve opening TA detected in 4 is read.

In step 332, the actual phase difference Δθ of the intake valve camshaft 131 with respect to the crankshaft 113 is _calculated based on the first pulse θ _c and the second pulse θ _i . In step 333, the target phase difference Dθ is obtained as a function of the internal combustion engine speed N _e and the throttle valve opening TA.
Then, in step 334, the opening degree α of the control valve 134 is determined based on the target phase difference Dθ and the actual phase difference Δθ, and this processing ends.

FIG. 5 is a flow chart of a second valve timing control routine executed by the control unit 16 in the second aspect of the present invention. The first step is the same as the step number of the first valve timing control routine. The same processing as the valve timing control routine is executed. In step 31 the battery (not shown.) Load the voltage V of, whether the voltage V is predetermined recovery voltage V _R or in step 51 is determined.

The return voltage V _R is set to a voltage (eg, 10 V) higher than the lower limit voltage V _{L in} order to give a so-called hysteresis characteristic. If an affirmative decision is made in step 51, it is decided that the battery voltage V has recovered and the routine proceeds to step 52, where it is decided whether or not the flag VBATH is "0". When the affirmative determination is made in step 52, it is determined that the battery voltage at the time of executing this routine last time is the lower limit voltage _VL , and the process proceeds to step 53.

In step 53, it is determined whether or not the target phase difference Dθ is less than or equal to a predetermined threshold phase difference Dθ _th , and if a positive determination is made, torque shock does not occur even if the feedback control is restored. Proceed to 54. In step 54, it is assumed that the battery voltage V has been restored, and the flag XBATH is set to "1".

When a negative determination is made in step 52, it is determined that the battery voltage is maintained at the return voltage V _R or higher, and the process directly proceeds to step 33. When a negative determination is made in step 51, the routine proceeds to step 55, where it is assumed that the battery voltage has not been restored, the flag XBATH is set to "1", and then the routine proceeds to step 34, where the opening α of the control valve 134 is set to "0". , Go to step 35.

If a negative determination is made in step 53, the target phase difference Dθ is greater than or equal to a predetermined threshold phase difference Dθ _{th and} it is assumed that torque shock will occur when returning to the feedback control, and the recovery is prohibited and the control valve 134 is turned off. The opening α is maintained at “0”. FIG. 6 is a graph for explaining the operation of the second invention, in which the vertical axis represents battery voltage V, torque and phase difference, and the horizontal axis represents time.

At time t ₁ , the battery voltage V becomes the lower limit voltage V _L
When it drops below, the actual phase difference is maintained at a predetermined value corresponding to the initial position of the VVT 133. Even if the battery voltage V becomes equal to or higher than the recovery voltage V _{R at} time t ₂ , the target phase difference D
Since θ is equal to or larger than the threshold phase difference Dθ _th , the return to the feedback control is prohibited.

Therefore, it is possible to suppress the shock from being generated in the torque as shown by the broken line. At time t ₃ , the target phase difference Dθ becomes equal to or smaller than the threshold phase difference Dθ _th , and the feedback control is restored. At this time, torque shock is generated, but it is suppressed within an allowable range. FIG. 7 is a control system diagram around the control valve 134 of the valve timing control device according to the third invention.
5, the opening signal α of the control valve 134 is a pulse signal whose duty ratio is controlled, and the control valve 134 is controlled to an opening proportional to the current value of the DC current supplied.

A linear solenoid IC 166 is installed between the control valve 134 and the control device 16, and a pulse signal output from the control device is converted into a DC current proportional to the duty ratio by the linear solenoid IC 166. FIG. 8 is a graph showing the conversion characteristic of the linear solenoid IC 166, in which the vertical axis represents the direct current and the horizontal axis represents the duty ratio.

Therefore, when the battery voltage drops, the conversion characteristic of the linear solenoid IC 166 fluctuates, and the output current decreases from the normal state. Therefore, the actual phase difference θ _i becomes smaller than the target phase difference D θ, and as a result, the duty ratio output from the control device 16 increases, which may cause torque shock when the battery voltage returns to normal.

The third invention is to solve this problem, and FIG. 9 shows a flowchart of a third valve timing control routine executed by the control unit 16 in the third invention. In step 31, the battery voltage V is read, and in step 33, feedback control processing is executed.

At step 91, the maximum duty ratio α _max corresponding to the battery voltage V is determined. FIG. 10 is a graph for determining the maximum duty ratio α _max , in which the vertical axis represents the maximum duty ratio α _max and the horizontal axis represents the battery voltage V. That is, when the battery voltage V is equal to or higher than the lower limit voltage V _L , the maximum duty ratio α _max is 100%, and the lower limit voltage V
_When it becomes _L or less, the maximum duty ratio α _max also becomes small in proportion to the battery voltage V.

In step 92, it is determined whether or not the opening degree signal α determined by the feedback control process is equal to or more than the maximum duty ratio α _max , and if a positive determination is made, step 9 is performed.
At step 3, the opening signal α is replaced with the maximum duty ratio α _max, and the routine proceeds to step 35. If a negative determination is made in step 92, the process directly proceeds to step 35. Therefore, even if the battery voltage drops, the duty ratio of the opening signal α is prevented from becoming excessive, and torque shock occurs when the battery voltage returns. Prevented from doing.

The fourth invention is a linear solenoid IC166.
Is used, the opening of the control valve 134 is directly controlled by the duty ratio of the pulse signal. In this case, control valve 1
Reference numeral 34 opens the valve against the biasing force of a spring (not shown) that gives a valve closing force by the force generated by the solenoid. Therefore, when the battery voltage V decreases, the opening degree decreases from the predetermined opening degree.

The fourth invention is directed to solving this problem, and FIG. 11 shows a flowchart of a fourth valve timing control routine executed by the control unit 16 in the fourth invention. In step 31, the battery voltage V is read, and in step 33, feedback control processing is executed.

In step 1101, the correction value Δα corresponding to the battery voltage V is determined. FIG. 11 is a graph for determining the correction value Δα, in which the vertical axis represents the correction value Δα and the horizontal axis represents the battery voltage V. That is, the correction value Δα is set to be smaller as the battery voltage becomes higher.

In step 1102, a correction value is added and corrected to the opening signal α determined in the feedback control processing, and it is determined in step 1103 whether the duty ratio of the opening signal α corrected is 100% or more. . Step 110
If the affirmative determination is made in step 3, the duty ratio of the opening degree signal α is limited to 100% in step 1104, and the process proceeds to step 35.

If a negative determination is made in step 1103, the process directly proceeds to step 35. In step 35, the opening signal α is output and this routine is finished. That is, in the fourth aspect of the present invention, the duty ratio is corrected to be larger as the battery voltage decreases, so that the decrease in the control valve opening due to the battery voltage decrease can be compensated.

[0044]

According to the valve timing control device for an internal combustion engine according to the first aspect of the present invention, when the power supply voltage drops below the lower limit voltage, the control valve is fully closed and the valve timing is mechanically set at the initial position of VVT. By fixing the timing to be determined, it becomes possible to suppress power consumption and prevent further reduction of the power supply voltage.

According to the valve timing control device for an internal combustion engine according to the second aspect of the present invention, if the target phase difference is large when the voltage returns to the return voltage or higher, the return to the feedback control is prohibited, so that It is possible to suppress the occurrence of the torque shock. According to the valve timing control device for an internal combustion engine of the third invention, the duty ratio of the pulse output from the control device when driving the solenoid valve via the linear solenoid IC is within the maximum duty ratio according to the power supply voltage. By restricting to, it is possible to suppress the occurrence of torque shock due to fluctuations in the power supply voltage.

According to the valve timing control device for the internal combustion engine of the fourth aspect of the present invention, the duty ratio of the pulse output from the control device when the solenoid valve is driven without passing through the linear solenoid IC depends on the power supply voltage. By making the correction, the valve timing can be accurately controlled even when the power supply voltage changes.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a valve timing control device for an internal combustion engine according to the present invention.

FIG. 2 is a cross-sectional view of the VVT.

FIG. 3 is a flowchart of a first valve timing control routine.

FIG. 4 is a detailed flowchart of feedback control processing.

FIG. 5 is a flowchart of a second valve timing control routine.

FIG. 6 is a graph for explaining the operation of the second invention.

FIG. 7 is a control system diagram around a control valve of a third invention.

FIG. 8 is a graph of conversion characteristics of a linear solenoid IC.

FIG. 9 is a flowchart of a third valve timing control routine.

FIG. 10 is a graph for determining the maximum duty ratio.

FIG. 11 is a flowchart of a fourth valve timing control routine.

FIG. 12 is a graph for determining a correction value.

[Explanation of symbols]

 111 ... Piston 113 ... Crankshaft 115 ... First magnetic sensor 124 ... Throttle valve opening sensor 13 ... Intake valve 131 ... Intake valve camshaft 133 ... VVT 134 ... Control valve 136 ... Second magnetic sensor 151 ... First Rotation speed sensor 16 ... Control device

Claims (4)

[Claims] 1. A state quantity detecting means for detecting a state quantity representing an operating state of an internal combustion engine, a phase difference detecting means for detecting an actual phase difference of a camshaft with respect to a crankshaft, and the phase difference detecting means. Operating phase calculating means for calculating an operating signal for matching the actual phase difference with the target phase difference determined based on the state quantity detected by the state quantity detecting means, and at least on both sides of the outer circumference and the inner circumference. A ring gear having a biasing means for biasing the operation signal computing means to an initial position when one of the teeth is a helical tooth and the operation signal computing means is in a disconnected state, and is fitted to one tooth of the ring gear and driven by a crankshaft. Timing pulley, a cap fitted to the other tooth of the ring gear and coupled to the camshaft, and the ring gear operated from the initial position by hydraulic pressure. A phase difference changing means composed of a hydraulic pressure supplying means for moving the rotary shaft to a position corresponding to the operation signal calculated by the operation signal calculating means, a voltage detecting means for detecting the voltage of the DC power supply, and the voltage A valve timing control device for an internal combustion engine, comprising: a control interruption means for turning off the operation signal calculation means when the voltage detected by the detection means becomes equal to or lower than a predetermined lower limit voltage. 2. A control return means for returning control by the operation signal calculation means when the voltage detected by the voltage detection means becomes equal to or higher than a predetermined return voltage, and a position detected by the phase difference detection means. And a recovery prohibiting means for prohibiting recovery by the control recovering means when the deviation between the phase difference and the target phase difference determined based on the state quantity detected by the state quantity detecting means is a predetermined threshold deviation or more. The valve timing control device for an internal combustion engine according to claim 1, further comprising: 3. A state quantity detecting means for detecting a state quantity representing an internal combustion engine operating state, a phase difference detecting means for detecting an actual phase difference of the camshaft with respect to a crankshaft, and the phase difference detecting means. Pulse signal calculation means for calculating the duty ratio of the pulse signal in order to match the actual phase difference with the target phase difference determined based on the state quantity detected by the state quantity detection means, and the voltage of the DC power supply. Voltage detecting means for detecting, maximum duty ratio calculating means for calculating the maximum duty ratio corresponding to the voltage detected by the voltage detecting means, and duty ratio of the pulse signal calculated by the pulse signal calculating means for the maximum duty A duty ratio limiting means for limiting the maximum duty ratio calculated by the ratio calculating means; Signal converting means for converting the pulse signal into a DC signal corresponding to the duty ratio, and when the pulse signal calculating means is in a disconnection state when at least one of the outer and inner circumferences is formed with teeth having oblique teeth A ring gear having a biasing means for biasing to a position; a timing pulley fitted to one tooth of the ring gear and driven by a crankshaft; and a timing pulley fitted to the other tooth of the ring gear and coupled to a camshaft. And a hydraulic pressure supply means for moving the ring gear in the rotation axis direction from the initial position to a position according to the DC signal converted by the signal conversion means by hydraulic pressure, and a phase difference changing means. Valve timing control device for internal combustion engine. 4. A state quantity detecting means for detecting a state quantity representing an internal combustion engine operating state, a phase difference detecting means for detecting an actual phase difference of a camshaft with respect to a crankshaft, and the phase difference detecting means. Pulse signal calculation means for calculating the duty ratio of the pulse signal in order to match the actual phase difference with the target phase difference determined based on the state quantity detected by the state quantity detection means, and the voltage of the DC power supply. Voltage detecting means for detecting, duty ratio correcting means for correcting the duty ratio of the pulse signal calculated by the pulse signal calculating means in accordance with the voltage detected by the voltage detecting means, and at least on both sides of the outer circumference and the inner circumference. A ring gear having a biasing means for biasing the pulse signal computing means to an initial position when one of the teeth is a helical tooth and the pulse signal computing means is in a disconnected state; A timing pulley fitted to one tooth of the ring gear and driven by the crankshaft, a cap fitted to the other tooth of the ring gear and joined to the cam shaft, and the ring gear from the initial position by hydraulic pressure. A valve timing control apparatus for an internal combustion engine, comprising: a phase difference changing unit configured to include a hydraulic pressure supply unit configured to move in a rotation axis direction to a position according to a pulse signal corrected by the duty ratio correction unit.