Valve timing control device

Abstract

To provide a valve opening / closing timing control device for accurately performing the control of valve opening / closing timing (valve timing) even if a rotational speed of a camshaft is temporarily changed.SOLUTION: A phase control unit 50 of a valve opening / closing timing control device comprises a phase control unit 50C for acquiring a relative rotation phase as an actual phase on the basis of a crank angle signal detected by a crank angle sensor 16 and a cam angle signal detected by a cam angle sensor 17, and controlling the rotation of an electric motor M in a direction in which a deviation between a target phase and the actual phase is reduced. The phase control unit also comprises a signal calibration unit 50B for setting an interpolation signal of detection timing which is optimized by being replaced to an improper signal which is determined to be improper when the detection signal of the cam angle signal is determined to be improper.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a valve timing control device. [Background technology]

[0002] Patent Document 1 describes a device for setting valve opening and closing timing (valve timing) in an internal combustion engine using the driving force of an electric motor. The device acquires a crank angle signal from a crank angle sensor and a cam angle signal from a cam angle sensor, and calculates the actual phase of a valve opening and closing timing control device (valve timing device) based on these signals.

[0003] The valve timing control device described in Patent Document 1 advances the valve timing by making the rotational speed of the motor relatively faster than the rotational speed of the camshaft, and retards the valve timing by making the rotational speed of the motor relatively slower than the rotational speed of the camshaft.

[0004] Furthermore, in Patent Document 1, the actual phase is detected based on the time difference from the timing at which TDC (compression top dead center) is detected in the crank angle signal to the timing at which a predetermined cam angle signal is detected. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-51349 Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Document 1, the crank angle sensor has a timing rotor that rotates integrally with the crankshaft and has a sensor that detects the presence or absence of the teeth as the crankshaft rotates. Similarly, the cam angle sensor has a timing rotor that rotates integrally with the camshaft and has a sensor that detects the presence or absence of the teeth as the camshaft rotates.

[0007] Furthermore, when controlling the valve timing (valve timing) of the valve timing control device, the motor is controlled in a manner that feeds back the actual phase calculated based on the detection of the crank angle sensor and the detection of the cam angle sensor until the actual phase reaches the target phase.

[0008] However, because the cam angle sensor detects the rotational angle of a timing rotor directly connected to the camshaft, for example, when the camshaft is in a position where pressure from the cam surface opens the intake or exhaust valve, the rotational speed (angular velocity) of the camshaft temporarily decreases, which can cause the cam angle sensor's detection timing to deviate from the appropriate timing. As a result, there is concern that this could lead to a decrease in the accuracy of the feedback control that determines the opening and closing timing.

[0009] Because the camshaft rotates in sync with the crankshaft via a timing chain or timing belt, it was conceivable that, for example, when a specific cylinder reaches top dead center of compression, the load acting on the piston would temporarily reduce the rotational speed (angular velocity) of the camshaft, which, for the same reasons as mentioned above, would lead to a reduction in the accuracy of the feedback control that determines the opening and closing timing.

[0010] For these reasons, there is a demand for a valve timing control device that can control the valve timing with high precision even if the rotational speed of the camshaft temporarily changes. [Means for solving the problem]

[0011] A valve opening / closing timing control device according to the present invention is characterized by comprising: a drive-side rotor that rotates synchronously with a crankshaft of an internal combustion engine; a driven-side rotor that rotates integrally with a camshaft for opening and closing valves of the internal combustion engine; a phase adjustment mechanism that sets the relative rotation phase between the drive-side rotor and the driven-side rotor around a rotation axis by driving rotation of an electric motor; a phase sensing section that acquires the relative rotation phase; and a phase control unit that controls the electric motor to set the relative rotation phase based on the result acquired by the phase sensing section, and the phase sensing section includes a crank angle sensor that detects the rotation angle from a rotation reference when the crankshaft rotates; and a cam angle sensor that detects a cam angle signal at each of a plurality of preset rotation angles when the crankshaft makes one rotation, and the phase control unit includes an actual phase acquisition section that acquires the relative rotation phase as an actual phase based on the crank angle signal detected by the crank angle sensor and the cam angle signal detected by the cam angle sensor, a phase control section that controls the rotation of the electric motor in a direction that reduces the deviation between a target phase acquired from an external source and the actual phase, and a signal calibration section that, when it is determined that the detection timing of the cam angle signal deviates from the appropriate timing and is therefore inappropriate, sets an interpolated signal of the appropriate detection timing in place of the inappropriate signal that has been determined to be inappropriate.

[0012] According to this characteristic configuration, when the signal calibration unit determines that the detection timing of the cam angle signal is improper, an interpolation signal with an optimized detection timing is set in place of the improper signal indicating the improper detection timing. This makes it possible to obtain an accurate actual phase based on the cam angle signal and crank angle signal optimized by the interpolation signal, or based on the electric motor rotational speed signal and crank angle signal, thereby enabling to improve the accuracy of phase control. Therefore, a valve timing control device is configured that controls the valve timing phase with high precision even if the rotational speed of the camshaft temporarily changes.

[0013] In addition to the above configuration, the cam angle sensor may include a rotor that rotates integrally with the camshaft and has a set number of teeth on its outer periphery, and a sensor unit that detects one edge of the teeth in the rotational direction as the camshaft rotates, and the signal calibration unit may store the detection timing of the cam angle signal detected by the cam angle sensor when the camshaft makes at least one rotation with the actual phase fixed, and perform identification processing that enables identification of the improper signal from the cam angle signals based on the stored detection timing.

[0014] According to this, the cam angle sensor detects a set number of cam angle signals at the sensor unit when the camshaft rotates once. The signal calibration unit stores the detection timing of the cam angle signal when the camshaft rotates at least once while the actual phase is fixed, and can identify improper signals whose detection timing deviates from the appropriate timing based on the interval between the stored detection timings through identification processing.

[0015] In addition to the above configuration, the phase adjustment mechanism may have a configuration in which the output shaft of the electric motor rotates in the same direction as the rotation direction of the camshaft at a uniform speed as the camshaft to fix the actual phase, and adjust the actual phase by making the rotational speed of the output shaft of the electric motor different from the rotational speed of the camshaft, and the signal calibration unit may perform an identification process in which the internal combustion engine is operated, the electric motor is driven to fix the actual phase, and a rotational speed signal of the output shaft of the electric motor is stored for each unit time in a time domain in which the camshaft makes at least one rotation, and the signal calibration unit identifies, as the improper signal, a cam angle signal corresponding to one of the stored rotational speed signals at the detection timing in which a difference in rotational speed to be compared is larger or smaller than a predetermined value.

[0016] According to this, the output shaft of the electric motor rotates at the same speed as the camshaft so as to fix the actual phase, and the signal calibration unit stores the rotational speed signal of the output shaft of the electric motor for each unit time. Therefore, for example, if the cam angle signal detected by the cam angle sensor changes in the delayed direction as the rotational speed of the camshaft decreases, the stored rotational speed of the output shaft decreases. For this reason, the cam angle signal corresponding to the decreased rotational speed among the rotational speeds stored by the identification process can be set as an inappropriate signal.

[0017] In addition to the above configuration, the signal calibration unit may perform machine learning to set an area where the improper signal exists as an NG area that can be identified by the crank angle signal by executing the identification process at any time at a timing where the actual phase is fixed while the internal combustion engine is operating, and after the machine learning, update judgment map data of a data structure that can identify the NG area, which is determined by the number of cylinders and cam torque of the internal combustion engine, using the crank angle signal and the previous actual phase.When phase control is performed by the phase control unit, if it is determined that the detection timing of the cam angle signal identified by the crank angle signal and the actual phase is included in the NG area, it may be possible to set the interpolated signal instead of the improper signal included in the NG area.

[0018] This allows machine learning to update the judgment map information, which designates the area where an inappropriate signal exists as an NG area. Furthermore, when controlling the relative rotation phase after updating the judgment map information, if it is determined based on the crank angle signal and the actual phase that the detection timing of the cam angle sensor is included in the NG area in the updated judgment map data, it is possible to set an interpolated signal of appropriate detection timing instead of the cam angle signal (inappropriate signal).

[0019] A valve opening / closing timing control device according to the present invention is characterized by comprising: a drive-side rotor that rotates synchronously with a crankshaft of an internal combustion engine; a driven-side rotor that rotates integrally with a camshaft for opening and closing valves of the internal combustion engine; a phase adjustment mechanism that sets the relative rotation phase between the drive-side rotor and the driven-side rotor around a rotation axis by driving rotation of an electric motor; a phase sensing unit that acquires the relative rotation phase; and a phase control unit that controls the electric motor to set the relative rotation phase based on the result acquired by the phase sensing unit, wherein the phase sensing unit includes a crank angle sensor that detects a rotation angle from a rotation reference when the crankshaft rotates, and a phase adjustment mechanism that adjusts the relative rotation phase by a plurality of preset values when the camshaft makes one rotation. and a cam angle sensor that detects a cam angle signal for each rotation angle of the crankshaft, and the phase control unit includes an actual phase acquisition section that acquires the relative rotation phase as an actual phase based on the crank angle signal detected by the crank angle sensor and the cam angle signal detected by the cam angle sensor, a phase control section that controls the rotation of the electric motor in a direction that reduces the deviation between a target phase acquired from outside and the actual phase, and a signal calibration section that, when it is determined that the detection timing of the cam angle signal deviates from an appropriate timing and is therefore inappropriate, changes the detection timing of the inappropriate signal and the appropriate signal in a direction that reduces the difference in detection timing between the inappropriate signal determined to be inappropriate and the appropriate signal determined to be appropriate.

[0020] According to this characteristic configuration, when the signal calibration unit determines that the detection timing of the cam angle signal is inappropriate, the detection timing of the inappropriate signal and the appropriate signal is changed in a direction that reduces the difference in detection timing between the inappropriate signal, which has inappropriate detection timing, and the appropriate signal, which has appropriate detection timing.This reduces the fluctuation range of the detection timing of the cam angle signal based on the appropriate detection timing, thereby reducing the error in the actual phase and enabling the accuracy of phase control to be improved. Therefore, a valve timing control device was constructed that controls the valve timing with high precision even if the rotational speed of the camshaft temporarily changes.

[0021] The valve opening / closing timing control device according to the present invention is characterized by comprising: a drive-side rotor that rotates synchronously with the crankshaft of an internal combustion engine; a driven-side rotor that rotates integrally with a camshaft for opening and closing valves of the internal combustion engine; a phase adjustment mechanism that sets the relative rotational phase between the drive-side rotor and the driven-side rotor about a rotation axis by driving rotation of an electric motor; a phase sensing unit that acquires the relative rotational phase; and a phase control unit that controls the electric motor to set the relative rotational phase based on the result acquired by the phase sensing unit, wherein the phase sensing unit comprises a crank angle sensor that detects the rotation angle from a rotational reference as the crankshaft rotates, and a cam angle sensor that detects a cam angle signal at each of a plurality of preset rotation angles as the camshaft makes one rotation; and if it is determined that the detection timing of the cam angle signal is inappropriate because it deviates from the appropriate timing, the phase sensing unit notifies an engine control unit that controls the internal combustion engine of the inappropriateness, and the engine control unit changes the ignition timing and the air amount calculation method in response to this notification.

[0022] According to this characteristic configuration, if it is determined that the detection timing of the cam angle signal is inappropriate because it deviates from the appropriate timing, the engine control unit is notified of the inappropriateness, and this notification makes it possible to change the ignition timing and air volume calculation method by controlling the engine control unit. Therefore, a valve timing control device has been constructed that can change the engine ignition timing and air volume calculation method in response to a temporary change in the rotation of the camshaft. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. [Figure 2] FIG. 2 is a block diagram of an engine control unit and a phase control unit according to the first embodiment. [Figure 3] FIG. 2 is a cross-sectional view of the valve timing control device. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5]FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6] 5 is a flowchart showing a control sequence of a learning process and a phase control process in the first embodiment. [Figure 7] 4 is a flowchart of a learning processing routine according to the first embodiment. [Figure 8] 4 is a flowchart of a phase control routine according to the first embodiment. [Figure 9] 4 is a timing chart showing torque and cam angle signals. [Figure 10] 4 is a timing chart showing reference detection timing and actual detection timing of a cam angle signal. [Figure 11] 10 is a timing chart showing the reference detection timing of the cam angle signal and the rotation speed of the motor when the actual phase is fixed. [Figure 12] 10 is a chart showing the relationship between the compression top dead center and an improper region. [Figure 13] FIG. 10 is a block diagram of an engine control unit and a phase control unit according to a second embodiment. [Figure 14] 10 is a flowchart of a phase control routine according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [First embodiment: basic configuration] Fig. 1 shows a part of an engine E as an internal combustion engine, and Fig. 2 shows an engine control unit 40 that controls the engine E, and a phase control unit 50 that controls the phase of a valve timing control device VT. As shown in Figs. 1 and 2, the engine E is equipped with a valve timing control device VT that sets the opening and closing timing (valve timing) of an intake valve Va, and this valve timing control device VT performs feedback control using a phase control unit 50 to converge the actual phase of the valve timing control device VT to a target phase transmitted from the engine control unit 40.

[0025] 1 shows an engine E that is installed in a vehicle such as a passenger car, etc. The valve timing control device VT performs phase control using a phase control motor M (an example of an electric motor) shown in FIG.

[0026] In a vehicle, when starting the engine E, cranking is performed by the starter motor 15 shown in Fig. 2. During cranking, the phase control unit 50 obtains the actual phase of the valve timing control device VT from a signal from the phase sensing unit PS, and sets the opening / closing timing (valve timing) of the intake valve Va to a value suitable for starting by performing phase control that feeds back this actual phase.

[0027] Furthermore, engine E is configured as a six-cylinder type, and the phase control unit 50 distinguishes between cylinders from the signal of the phase sensing unit PS during cranking. The engine control unit 40 supplies fuel to the combustion chamber of each cylinder at an appropriate timing after the start of cranking based on the result of the cylinder distinction, ignites the mixture in the combustion chamber, and starts engine E.

[0028] 〔engine〕 As shown in Figures 1 and 3, engine E (an example of an internal combustion engine) has a cylinder head 3 connected to the top of a cylinder block 2 that supports a crankshaft 1. Engine E is a four-stroke engine in which pistons 4 are slidably housed in multiple cylinder bores formed in the cylinder block 2, and the pistons 4 are connected to the crankshaft 1 by connecting rods 5. As mentioned above, engine E is a six-cylinder type, but Figure 3 shows a schematic structure of engine E with some of the six cylinders omitted.

[0029] The engine E has an intake valve Va and an exhaust valve Vb in a cylinder head 3, and an intake camshaft 7 (an example of a camshaft for opening and closing a valve) that controls the intake valve Va at the top of the cylinder head 3, and an exhaust camshaft 8 that controls the exhaust valve Vb.

[0030] In the engine E, a timing belt 6 (which may be a timing chain) is wound around an output pulley 1P of the crankshaft 1, a timing pulley 21P of a drive case 21 (an example of a drive-side rotor) of the valve timing control device VT, and a drive pulley 8P of the exhaust camshaft 8. This causes the crankshaft 1 and the drive case 21 to rotate synchronously.

[0031] The cylinder head 3 is equipped with an injector 9 that injects fuel into the combustion chamber and a spark plug 10 that ignites the air-fuel mixture in the combustion chamber. In addition, the cylinder head 3 is connected to an intake manifold 11 that supplies air to the combustion chamber via an intake valve Va, and an exhaust manifold 12 that sends out combustion gas from the combustion chamber via an exhaust valve Vb.

[0032] 1 and 2, engine E is provided with a crank angle sensor 16 near crankshaft 1 that can detect the rotation angle of crankshaft 1, and a cam angle sensor 17 that can detect the rotation angle of intake camshaft 7. Crank angle sensor 16 and cam angle sensor 17 together constitute a phase sensing unit PS.

[0033] The phase sensing section PS inputs the crank angle signal detected by the crank angle sensor 16 and the cam angle signal detected by the cam angle sensor 17 to the phase control unit 50. In the phase control unit 50, the actual phase acquisition section 51 acquires the relative rotational phase (the above-mentioned actual phase) about the rotation axis X between the drive case 21 and the internal rotor 22 of the valve timing control device VT, based on a predetermined timing of the input crank angle signal and the detection timing of one of the four cam angle signals.

[0034] 2, the crank angle sensor 16 includes a disk portion 16D that rotates integrally with the crankshaft 1, and a non-contact crank sensor portion 16S that detects a plurality of teeth 16T on the outer periphery of the disk portion 16D. A reference point 16n that does not include teeth 16T is formed at one location on the outer periphery of the disk portion 16D. The disk portion 16D and teeth 16T are integrally formed from a magnetic material such as steel, and a pickup type crank sensor portion 16S is used.

[0035] As a result, the crank angle sensor 16 continuously detects pulse signals by the crank sensor section 16S as the crankshaft 1 rotates, and by counting these pulse signals based on the reference point 16n, it is possible to obtain a crank angle signal.

[0036] 2, the cam angle sensor 17 includes a rotor 17D that rotates integrally with the intake camshaft 7, and a cam sensor unit 17S (an example of a cam sensor) that detects four teeth 17T on the outer periphery of the rotor 17D. The rotor 17D and teeth 17T are integrally formed from a magnetic material such as steel, and a pickup type cam sensor unit 17S is used.

[0037] The cam angle sensor 17 is configured to detect the edge of the tooth portion 16T in the rotational direction (circumferential direction), and a cam angle signal is detected every 90 degrees when the intake camshaft 7 rotates once. As a result, four signals are detected when the intake camshaft 7 rotates once.

[0038] Furthermore, the cam angle sensor 17 distinguishes between cylinders based on the rotation angle of the intake camshaft 7 relative to the rotation angle of the crankshaft 1 by varying the circumferential lengths of the four tooth portions 17T.

[0039] In particular, in the phase control, the crank angle sensor 16 counts the number of teeth each time it detects an edge of the tooth portion 16T that is adjacent to the space of the reference point 16n, and calculates the actual phase based on the count and the time span from the detection timing of the edge from which the number of teeth was counted to the detection timing of a predetermined edge of the four tooth portions 17T of the cam angle sensor 17.

[0040] Therefore, when the rotation speed of intake camshaft 7 fluctuates, the timing at which the edges of teeth 17T of cam angle sensor 17 are detected also fluctuates, making it impossible to accurately determine the actual phase, leading to a decrease in the accuracy of phase control. For this reason, phase control unit 50 is provided with a signal calibration section 50B, which determines whether a signal is inappropriate and sets correction signals for transmission and detection timing in engine control. These control modes will be described later.

[0041] [Valve timing control device] 1 and 3 to 5, the valve timing control device VT has a drive case 21 (an example of a driving-side rotor) and an inner rotor 22 (an example of a driven-side rotor), and is also equipped with a phase adjustment mechanism that sets the relative rotational phase between them. The phase adjustment mechanism has a gear reduction mechanism that sets the relative rotational phase by driving a phase control motor M (an example of an electric motor).

[0042] The drive case 21 has a timing pulley portion 21P formed on its outer periphery, and is disposed coaxially with the rotational axis X of the intake camshaft 7. The inner rotor 22 is housed within the drive case 21 so as to be rotatable relative to the drive case 21, and is connected and fixed to the intake camshaft 7 coaxially by connecting bolts 23.

[0043] The valve timing control device VT has a phase adjustment mechanism disposed between the drive case 21 and the inner rotor 22. A front plate 24 is disposed in a position that covers the opening of the drive case 21, and this front plate 24 is fastened to the drive case 21 by a plurality of fastening bolts 25.

[0044] 4 and 5, the valve timing control device VT rotates as a whole in a driving rotation direction S due to the driving force of the timing belt 6. The direction in which the relative rotation phase of the internal rotor 22 with respect to the drive case 21 is displaced in the same direction as the driving rotation direction S due to the driving force of the phase control motor M is called the advance direction Sa, and the displacement in the opposite direction is called the retard direction Sb.

[0045] The valve timing control device VT functions to increase the amount of intake air at the intake valve Va by shifting the relative rotational phase in the advance direction Sa, and conversely, to reduce the amount of intake air at the intake valve Va by shifting the relative rotational phase in the retard direction Sb.

[0046] [Valve timing control device: Phase adjustment mechanism] As shown in Figures 3 to 5, the phase adjustment mechanism includes an inner rotor 22, a ring gear 26 formed on the inner periphery of the inner rotor 22, an inner gear 27, an eccentric cam body 28, and a joint portion J. The ring gear 26 has a plurality of internal teeth 26T formed on the inner periphery of the inner rotor 22, the internal teeth 26T being centered on the rotation axis X. The inner gear 27 has a plurality of external teeth 27T formed on its outer periphery. The inner gear 27 is disposed coaxially with an eccentric axis Y oriented parallel to the rotation axis X, and some of the external teeth 27T mesh with some of the internal teeth 26T of the ring gear 26.

[0047] In this phase adjustment mechanism, the number of teeth of the external teeth portion 27T of the inner gear 27 is one less than the number of teeth of the internal teeth portion 26T of the ring gear 26.

[0048] The joint J is configured as an Oldham coupling that prevents relative rotation between the drive case 21 and the inner gear 27 while allowing the inner gear 27 to move in a direction perpendicular to the rotation axis X relative to the drive case 21.

[0049] The eccentric cam body 28 is supported by a first bearing 31 on the front plate 24 so as to rotate coaxially with the rotation axis X. An eccentric cam surface 28A is integrally formed with the eccentric cam body 28 and is centered on an eccentric axis Y that is oriented parallel to the rotation axis X, and the inner gear 27 is rotatably supported by the eccentric cam surface 28A via a second bearing 32. Furthermore, a spring body 29 is fitted into a recess formed in the eccentric cam surface 28A, and the biasing force of the spring body 29 is applied to the inner gear 27 via the second bearing 32.

[0050] The eccentric cam body 28 is cylindrical in shape, and a pair of engagement grooves 28B are formed on the inner periphery in a position parallel to the rotation axis X. As a result, a part of the internal teeth portion 26T of the ring gear 26 meshes with a part of the external teeth portion 27T of the inner gear 27.

[0051] 3 and 4, the joint J has a joint member 33 formed by pressing a plate material. The joint member 33 has an annular central portion, a pair of engagement arms 33A protruding outward from the annular central portion, and a pair of engagement recesses 33B formed to communicate with the space in the annular central portion. In addition, the joint J has the pair of engagement arms 33A of the joint member 33 engaged with the engagement groove portion 21G of the drive case 21, and the pair of engagement recesses 33B of the joint member 33 engaged with the engagement protrusions 27U of the inner gear 27.

[0052] In this joint portion J, the joint member 33 is engaged so as to be freely displaceable in the linear direction connecting the pair of engaging groove portions 21G of the drive case 21, and the inner gear 27 is engaged with the joint member 33 so as to be freely displaceable in the linear direction connecting the pair of engaging protrusions 27U.

[0053] The phase control motor M is a brushless DC motor and is supported by the engine E. The output shaft Ma of this phase control motor M is provided with an engagement pin 34 that is oriented perpendicular to the direction in which the output shaft Ma projects, and both ends of this engagement pin 34 are fitted into engagement grooves 28B on the inner periphery of the eccentric cam body 28. As a result, the driving force of the phase control motor M rotates the eccentric cam body 28.

[0054] In the valve timing control device VT, considering the operation mode of the phase adjustment mechanism when the engine E is stopped, when the driving force of the phase control motor M causes the eccentric cam body 28 to rotate about the rotation axis X, the eccentric cam surface 28A also rotates about the rotation axis X. As a result of this rotation, the inner gear 27 begins to revolve about the rotation axis X. During this revolution, the meshing position between the external teeth portion 27T of the inner gear 27 and the internal teeth portion 26T of the ring gear 26 is displaced along the inner periphery of the ring gear 26, so that a force acts on the inner gear 27 to rotate about the eccentric axis Y.

[0055] Then, when the inner gear 27 has revolved once, a rotational force (rotational force) acts to rotate the inner gear 27 by an angle (angle corresponding to one tooth) equivalent to the difference (tooth number difference) between the number of teeth of the internal tooth portion 26T of the ring gear 26 and the number of teeth of the external tooth portion 27T of the inner gear 27.

[0056] As described above, the joint J restricts the rotation of the inner gear 27 relative to the drive case 21, so even if the driving force of the phase control motor M rotates the eccentric cam body 28, the inner gear 27 does not rotate relative to the drive case 21. Instead, the rotational force acting on the inner gear 27 rotates the ring gear 26 relative to the drive case 21, and the inner rotor 22 rotates integrally with the ring gear 26. As a result, the rotational phase of the intake camshaft 7 relative to the drive case 21 is adjusted.

[0057] [Outline of Phase Adjustment] The valve timing control device VT drives and rotates the output shaft Ma of the phase control motor M in the same direction and at the same speed as the rotational speed of the intake camshaft 7, thereby maintaining a fixed state in which the eccentric cam body 28 and the inner gear 27 do not rotate relative to each other. This maintains the relative rotational phase between the drive case 21 and the inner rotor 22, and maintains the opening and closing timing (valve timing) of the intake valve Va.

[0058] In addition, by increasing or decreasing the rotational speed of the phase control motor M based on the rotational speed of the intake camshaft 7, the relative rotational phase is displaced in the advance direction Sa or the retard direction Sb, thereby changing the opening and closing timing (valve timing) of the intake valve Va.

[0059] [Engine Control Unit] The engine control unit 40 is configured as an ECU (engine control unit) that controls the engine E, and as shown in FIG. 2, receives information for controlling the engine E and outputs control signals for controlling a starter motor 15 that cranks the engine, an injector 9 that supplies fuel to the combustion chamber, and an ignition plug 10 that ignites the air-fuel mixture in the combustion chamber.

[0060] The engine control unit 40 includes a start control unit 41, an operation control unit 42, and a stop control unit 43. The start control unit 41 performs start control to start the engine E, the operation control unit 42 performs operation control (such as control of the opening and closing timing of the intake valve Va) required to maintain the operation of the engine E when the engine E is operating, and the stop processing unit performs stop control required to stop the engine E.

[0061] The start control unit 41, the operation control unit 42, and the stop control unit 43 are configured by software, but it is also possible to configure a part of them by hardware.

[0062] [Phase control unit] As shown in FIG. 2, the phase control unit 50 of the first embodiment includes a cylinder discrimination section 50A, a signal calibration section 50B, and a phase control section 50C.

[0063] The cylinder discrimination unit 50A discriminates between the six cylinders when starting the engine E, enabling the setting of the ignition order for each cylinder. The phase control unit 50C controls the rotation of the phase control motor M in a direction that reduces the deviation between the target phase obtained from an external source and the actual phase.

[0064] When the signal calibration unit 50B determines that the crank angle signal detected by the crank angle sensor 16 is an inappropriate signal because it deviates from the detection timing, the signal calibration unit 50B refers to an optimized detection timing interpolation signal (any of the reference detection timings Ta, Tb, Tc, and Td shown in Figures 9 to 11) in place of the inappropriate signal, and sets the referenced detection timing.

[0065] In particular, the signal calibration unit 50B performs a process for identifying an NG area where an improper signal is detected, and stores judgment map data including the NG area. The judgment map data is determined based on the number of engine cylinders and cam torque, and has a data structure that allows the NG area to be identified based on the crank angle value and the actual phase, and the NG area is updated by machine learning. This judgment map data is stored in the storage unit 57.

[0066] As a result, after storing the determination map data in the memory unit 57, the signal calibration unit 50B can determine whether the detection timing is in the NG region in the latest updated determination map data by referring to the updated determination map data based on the crank angle value and actual phase at the detection timing when the cam angle signal is detected.

[0067] When phase control unit 50C performs phase control, if it determines by referring to the determination map data that the cam angle signal is included in the NG region, it sets an interpolation signal (appropriate signal) in place of the crank angle signal (inappropriate signal) detected in the NG region. In other words, highly accurate phase control is achieved in phase control unit 50C without being affected by the amount of fluctuation in the detection timing of the cam angle signal, etc. Details of these control modes will be described later.

[0068] The cylinder discrimination unit 50A obtains the correspondence between the rotational attitude of the crankshaft 1 and the rotational attitude of the intake camshaft 7 based on the crank angle signal and cam angle signal obtained from the phase sensing unit PS when the engine E is started, thereby enabling the setting of the ignition order for each cylinder.

[0069] The phase control unit 50C has an actual phase acquisition unit 51 and a phase setting unit 52. The actual phase acquisition unit 51 acquires an actual phase (relative rotational phase) about the rotation axis X between the drive case 21 and the internal rotor 22 of the valve timing control device VT based on the crank angle signal and the cam angle signal output by the signal calibration unit 50B.

[0070] The phase setting unit 52 controls the phase control motor M in a direction to reduce the deviation between the target phase and the actual phase acquired from the actual phase acquisition unit 51. Furthermore, the phase control unit 50C outputs a control current corresponding to the control signal output from the phase setting unit 52 to the phase control motor M via the motor driver 53.

[0071] The signal calibration unit 50B includes a cam torque determination unit 55 that determines the delay (amount of deflection) in the detection timing of the cam angle signal, a map data update unit 56 that updates the determination map data, a storage unit 57 consisting of a nonvolatile memory for storing the determination map data, and an interpolation signal setting unit 58.

[0072] [Phase control unit: explanation of cam angle signal] As shown in Figure 9, when engine E is running, pistons 4 reach compression top dead center (TDC) in the following order of cylinders: #1, #5, #3, #6, #2, #4 (TDC is shown at the top along the horizontal axis). Each time a cylinder reaches compression top dead center (TDC), the torque acting on intake camshaft 7 fluctuates, as shown along the horizontal axis labeled "torque" at the bottom of the figure.

[0073] The torque acting on the intake camshaft 7 not only comes from the cam portion formed on the intake camshaft 7, but also acts in a range of several tens of degrees in crank angle immediately after the piston 4 reaches the compression top dead center (TDC).

[0074] As shown in FIG. 9, when the engine E is running, a pulse signal (crank angle signal) from the crank sensor unit 16S is detected continuously at predetermined intervals in the horizontal axis direction indicated by "Crank."

[0075] As shown in Fig. 2, cam angle sensor 17 has four teeth 17T formed on rotor 17D, so that four cam angle signals are detected by cam sensor section 17S when intake camshaft 7 makes one rotation. The detection signal of cam angle sensor 17 in a hypothetical situation where no torque is applied is shown as "Cam(0)" in Fig. 9.

[0076] In a hypothetical situation where no torque is applied, the four cam angle signals are detected at regular intervals as shown as reference detection timings Ta, Tb, Tc, and Td in Figure 9. Furthermore, the reference detection timings Ta, Tb, Tc, and Td of the four cam angle signals are displaced in the crank angle direction relative to reference point 16n of the crank angle signal from crank angle sensor 16 in response to changes in the actual phase. Furthermore, once the actual phase is determined, the reference detection timings Ta, Tb, Tc, and Td of the four cam angle signals can be determined by a simple calculation based on the crank angle signal.

[0077] [Phase control unit: Cam angle signal fluctuation] If torque acts on intake camshaft 7 while it is rotating, the rotational speed (number of rotations per unit time) of intake camshaft 7 temporarily decreases, delaying the detection timing of the cam angle signal. Since actual phase acquisition unit 51 acquires the actual phase based on the timing of the crank angle signal and the detection timing of one of the four cam angle signals, a delay in the detection timing of the cam angle signal results in an error being included in the acquired actual phase, reducing the accuracy of phase control.

[0078] 10 shows the actual detection timings of the cam angle signals as detection timings Tax, Tbx, Tcx, and Tdx, which include delays in the detection timings. Therefore, when these detection timings are compared with the reference detection timings Ta, Tb, Tc, and Td described above, the corresponding timing differences Tag, Tbg, Tcg, and Tdg can be interpreted as fluctuations in the detection timings, as shown as "Cam(x)" in FIG. 10.

[0079] In order to eliminate the inconvenience of reducing the accuracy of phase control, the signal calibration unit 50B determines the fluctuation (basically a delay) in the detection timing due to the action of torque in the cam torque determination unit 55, and if the fluctuation is determined to exceed a set value, an identification process is performed to identify the cam angle signal with large fluctuation as an inappropriate signal.

[0080] 12, which is determined by the number of engine cylinders and the cam torque, the map data update unit 56 updates the inappropriate region G determination map data by machine learning so that even a region corresponding to an inappropriate signal can be identified as an NG region. By updating this determination map data, when the phase control unit 50C performs phase control, it refers to the latest updated determination map data, and if the result of this reference indicates that the acquisition timing of the cam angle signal is included in the NG region, it is possible to set a cam angle signal (appropriate signal) with detection timing optimized by the interpolated signal, instead of the cam angle signal (inappropriate signal) included in the NG region.

[0081] In this phase control unit 50, the actual phase acquisition section 51, phase setting section 52, cam torque determination section 55, determination condition data 55a, map data update section 56, and interpolation signal setting section 58 are each configured by software, but it is also possible to configure all or part of these sections by hardware.

[0082] [Control mode] 6, when the phase control unit 50 determines that learning is necessary at the start of the engine E (Yes in step #01), machine learning is performed by the signal calibration section 50B (step #100). After this, the phase control section 50C is enabled to control the relative rotation phase (step #200).

[0083] Machine learning is assumed to be performed periodically, but may also be performed, for example, every time the engine E is started, or according to manual operation when the vehicle is inspected.

[0084] Although the control method will not be described in detail, before the machine learning is performed, parameters are set to correct deviations in detection timing due to mounting errors between rotor 17D and cam sensor unit 17S that constitute cam angle sensor 17 or variations in sensitivity characteristics of the Hall elements and the like that constitute cam sensor unit 17S. Similarly, parameters are set in crank angle sensor 16 to correct deviations in detection timing.

[0085] [Learning Routine] As shown in the flowchart of FIG. 7, the learning process routine (step #100) recognizes the pattern of the cam angle signal by continuously acquiring the cam angle signal while the engine E is running (step #101).

[0086] Next, the detection timing of the cam angle signal is determined (step #102). Specifically, when determining the detection timing, the cam torque determination unit 55 continuously detects multiple cam angle signals when the intake camshaft 7 rotates several times for each actual phase in a valve timing where the actual phase of the valve timing control device VT is fixed between the most retarded and most advanced phases.

[0087] In step #102, the cam torque determination unit 55 performs either or both of a first identification process that identifies an improper signal from the detection timing of the fluctuation amount of the detection timing (timing differences Tag, Tbg, Tcg, Tdg shown in Figure 10) and a second identification process that identifies an improper signal from the change amount of the rotational speed of the phase control motor M shown in Figure 11.

[0088] When the intake camshaft 7 is rotated to perform machine learning, the crank angle signal and the cam angle signal are detected, but phase control based on these signals is not performed.

[0089] In both the first and second specifying processes, when multiple cam angle signals are detected as machine learning, the multiple cam angle signals are temporarily stored in memory along the time axis, and in synchronization with the multiple cam angle signals, the rotation signal of the phase control motor M and the crank angle (the number of pulses of the crank angle signal) are stored in memory along the time axis. Storing in memory along the time axis specifically means receiving a signal from the memory's data bus and writing the signal to the address at the received timing while incrementing the memory address with a signal at a set short interval.

[0090] As the first identification process, the cam torque determination unit 55 calculates four timing differences Tag, Tbg, Tcg, and Tdg by matching the detection timings Tax, Tbx, Tcx, and Tdx of the four actual cam angle signals with the four reference detection timings Ta, Tb, Tc, and Td, as shown in FIG. 10.

[0091] As described above, the cam angle signal is acquired when the intake camshaft 7 rotates several times. Therefore, in the first identification process, the signal whose average value of each of the four timing differences Tag, Tbg, Tcg, and Tdg exceeds a threshold value (any of the detection timings Tax, Tbx, Tcx, and Tdx of the actual four cam angle signals) is identified as an inappropriate signal.

[0092] In the first specifying process, it is assumed that an arbitrary cam pulse is used as the reference for measuring time, but an arbitrary crank pulse may also be used.

[0093] As the second identification process, the cam torque determination unit 55 averages the stored rotation speeds of the phase control motor M and identifies as an inappropriate signal a cam angle signal whose rotation speed has decreased or increased beyond a threshold value based on the average value from among the detection timings Tax, Tbx, Tcx, and Tdx of the four actual cam angle signals.

[0094] In Figure 11, the pulse signal (crank angle signal) from the crank sensor unit 16S is shown as "Crank," the reference detection timings Ta, Tb, Tc, and Td are shown as "Cam(0)," and the rotational speed signal of the phase control motor M is shown as "Motor."

[0095] As shown in Figure 11, the rotation speed of the phase control motor M changes in the region where the torque acting on the intake camshaft 7 fluctuates. Although not shown in the figure, for example, the four timing differences Tag, Tbg, Tcg, and Tdg between the detection timings Tax, Tbx, Tcx, and Tdx of the four actual cam angle signals increase in the region where the rotation speed decreases.

[0096] The signal representing the rotational speed of the phase-controlled motor M is essentially a continuous rectangular wave, and as the rotational speed decreases, the intervals between the rectangular waves expand in the direction of the crank angle (the horizontal axis in the figure). However, in the figure, the signal is shown as a wavy rotational speed signal, and the average speed obtained by calculation is shown as AV.

[0097] For this reason, among the cam angle signals, a cam angle signal that decreases or increases beyond a threshold value from the average speed AV is identified as an improper signal.

[0098] Thereafter, the region where the improper signal exists is determined to be an NG region, and the determination map data is updated to include this NG region and stored in the storage unit 57 (steps #104 and #105). This determination map data has a data structure that allows the NG region to be identified based on the crank angle signal and the actual phase.

[0099] [Another embodiment of the detection timing determination (step #102)] As a process for identifying the signal, an improper signal is identified using the timing chart in FIG. 12. When engine E is running, the crank speed increases immediately after compression top dead center (TDC), causing a large fluctuation in the detection timing. This increase is limited to a region displaced by a set angle F (approximately several tens of degrees) in the retard direction (to the right in FIG. 12) from compression top dead center (TDC).

[0100] The data shown in Fig. 12 shows the actual phase on the vertical axis and the crank angle CA on the horizontal axis, so that multiple compression top dead centers TDC are shown lined up on the horizontal axis. Furthermore, multiple regions displaced from compression top dead centers TDC in the retard direction (to the right in the figure) by a set angle F (for example, 20 crank angles) are shown by hatching in Fig. 12 as inappropriate regions G, and if a cam angle signal exists in this inappropriate region G, the cam angle signal will be identified as an inappropriate signal.

[0101] [Phase Control Routine] As shown in the flowchart of Figure 8, the phase control process (step #200) acquires the rotation speed (number of rotations per unit time) of the engine E (step #201), and if the acquired rotation speed exceeds a set speed (Yes in step #202), acquires the crank angle and actual phase, and references the determination map data based on these (steps #203 and #204). In other words, if the rotation speed is less than the set value, the calibration described below is not performed.

[0102] Next, if the detection timing of the detected cam angle signal is included in the NG area of the judgment map data (Yes in #205), the reference detection timings Ta, Tb, Tc, and Td are referenced, and if the NG area is determined, an NG judgment signal is sent (notified) to the engine control unit 40 (step #206), and calibration is performed by setting an interpolation signal of the reference detection timing corresponding to the NG area (step #207).

[0103] In step #206, if it is determined that the detection timing of the cam angle signal is inappropriate because it deviates from the appropriate timing, the engine control unit 40 is notified of this inappropriateness. As a result, the engine control unit 40 (which functions as a signal calibration unit) changes the ignition timing and the air volume calculation method. As a result, the engine E burns the air-fuel mixture at the appropriate ignition timing, and by changing the air volume calculation method, an appropriate intake volume is set.

[0104] In particular, in phase control, when the detection timing of cam angle sensor 17 in the NG region is calibrated by the control of step #207, processing based on the cam angle signal in phase control unit 50C is interrupted, and a signal of the timing corresponding to the cam angle signal (incorrect signal) in the NG region from among the four reference detection timings Ta, Tb, Tc, and Td is set in phase control unit 50C in place of the cam angle signal already input to phase control unit 50. That is, for example, if the timing difference Tbg of detection timing Tbx in the timing chart of FIG. 10 exceeds a threshold value, the detection timing of reference detection timing Tb is given instead of detection timing Tbx.

[0105] After this, actual phase acquisition unit 51 acquires an appropriate actual phase by calculation based on the crank angle signal and the detection timing of the cam angle signal, and phase setting unit 52 controls motor driver 53 based on the deviation between the acquired actual phase and the target phase, thereby controlling phase control motor M (steps #208 and #209). This control makes it possible to control valve timing with high accuracy, and thereafter, when it is determined that the deviation between the actual phase and the target phase has converged (Yes in step #210), phase control ends.

[0106] Second Embodiment In the second embodiment, the configuration of the engine E, the configuration of the valve timing control device VT, and the engine control unit 40 that controls the engine E are common to the first embodiment. In this second embodiment, components common to the first embodiment are assigned the same reference numerals as in the first embodiment. Also, a phase control unit 50 that controls the phase of the valve timing control device VT is different from that in the first embodiment, and the configuration of this phase control unit 50 will be described below.

[0107] [Phase control unit] As shown in FIG. 13, the phase control unit 50 of the second embodiment includes a cylinder discrimination section 50A, a signal calibration section 50B, and a phase control section 50C, similar to the first embodiment.

[0108] As shown in the flowchart of FIG. 14, the phase control unit 50 has the signal calibration unit 50B acquire the rotation speed (number of rotations per unit time) of the engine E (step #301), and if the acquired rotation speed exceeds the set speed (Yes in step #302), determine the detection timing of the cam angle signal (step #303).

[0109] The determination of the detection timing in step #303 determines whether the detection timing of the cam angle signal (signals of detection timings Tax, Tbx, Tcx, Tdx) detected by the cam angle sensor 17 is appropriate or inappropriate when the engine E is running. This determination is made by the signal calibration unit 50B, and is based on either or both of the first and second specific processing described in the first embodiment.

[0110] If the signal calibration unit 50B determines that the cam angle signal detected at the actual detection timing (detection timings Tax, Tbx, Tcx, Tdx) is an improper signal, the detection timing of the cam angle signal is calibrated (step #304). This calibration is achieved by setting the corresponding detection timing from the reference detection timings Ta, Tb, Tc, Td in place of the one (improper signal) that corresponds to the improper detection timing from among the four detection timings Tax, Tbx, Tcx, Tdx.

[0111] After this, actual phase acquisition unit 51 acquires an appropriate actual phase by calculation based on a predetermined timing of the crank angle signal and the detection timing of the cam angle signal, and phase setting unit 52 controls motor driver 53 based on the deviation between the acquired actual phase and the target phase, thereby controlling phase control motor M (steps #306 and #307). This control enables highly accurate phase control, and thereafter, when it is determined that the deviation between the actual phase and the target phase has converged (Yes in step #308), the phase control ends.

[0112] In the second embodiment, unlike the first embodiment, the judgment map data is not used for judgment. Instead, the appropriateness of the detection timing of the cam angle signal from cam angle sensor 17 is judged during the execution of the phase control routine. If it is judged to be inappropriate, a cam angle signal with appropriate detection timing is used in real time, thereby enabling highly accurate phase control.

[0113] [Another embodiment] The present invention may be configured as follows in addition to the above-described embodiments (common numbers and symbols are used to designate components having the same functions as those in the embodiments).

[0114] (a) When the detection timing of the cam angle signal is determined to be inappropriate, the signal calibration unit 50B is configured to change the detection timing of each of the inappropriate signal and the appropriate signal in a direction that reduces the difference in detection timing between the inappropriate signal determined to be inappropriate and the appropriate signal determined to be appropriate.

[0115] Specifically, if the detection timing is significantly delayed, the amount of deviation from the reference detection timing is reduced by advancing the detection timing, and even if the detection timing is close to the correct timing, the detection timing is delayed from the reference detection timing to reduce the difference in the amount of deviation between the four detection timings. This reduces the error in the actual phase and the fluctuation in the control amount in phase control, resulting in improved accuracy of phase control. This alternative embodiment (a) does not require setting an appropriate signal to calibrate the inappropriate signal.

[0116] (b) When using judgment map data, the offset amount (amount of deviation) between the inappropriate signal and the appropriate signal is calculated and stored in association with the NG area, and when performing phase control, if the detected cam angle signal is in the NG area, a calculation is performed to shift the detection timing by the offset amount based on the detection timing of the detected cam angle signal, thereby making it possible to set a calibration signal.

[0117] By setting the control mode in this way, it is no longer necessary to refer to the values of the reference detection timings Ta, Tb, Tc, and Td based on the actual phase, and a cam angle signal with appropriate detection timing can be set, allowing for highly accurate phase control.

[0118] (c) If it is determined that the value of the cam torque acting on the intake camshaft 7 exceeds a predetermined threshold, it is deemed that an improper signal has been detected, and the cam angle signal at that timing is identified as an improper signal.

[0119] That is, the determination of the improper signal in this alternative embodiment (c) is determined by the cam torque acting from the cam surface of the intake camshaft 7.

[0120] Therefore, in this alternative embodiment (c), it is possible to estimate a cam angle signal with a large fluctuation in the detection timing of the cam angle signal and estimate the NG area without performing the process of identifying an inappropriate signal using the first identification process or the second identification process described above. [Industrial Applicability]

[0121] The present invention can be used in a valve timing control device. [Explanation of symbols]

[0122] 1 crankshaft 7 Intake camshaft (camshaft) 16 Crank angle sensor 17 Cam angle sensor 17D Rotating Body 17S Cam sensor part (sensor part) 17T Teeth 21 Drive case (drive side rotor) 22 Internal rotor (driven rotor) 50B Signal calibration section 50C Phase control section 51 Actual phase acquisition unit E Engine (internal combustion engine) M Electric motor (phase control motor) Ma output shaft PS Phase sensing section VT Valve timing control device X rotation axis

Claims

1. a drive-side rotor that rotates synchronously with a crankshaft of an internal combustion engine; a driven-side rotor that rotates integrally with a camshaft for opening and closing valves of the internal combustion engine; a phase adjustment mechanism that sets the relative rotational phase between the drive-side rotor and the driven-side rotor around a rotation axis by driving rotation of an electric motor; a phase sensing unit that acquires the relative rotational phase; and a phase control unit that controls the electric motor to set the relative rotational phase based on the result acquired by the phase sensing unit; the phase sensing unit includes a crank angle sensor that detects a rotation angle from a rotation reference when the crankshaft rotates, and a cam angle sensor that detects a cam angle signal for each of a plurality of preset rotation angles when the camshaft makes one rotation, the phase control unit includes an actual phase acquisition section that acquires the relative rotational phase as an actual phase based on the crank angle signal detected by the crank angle sensor and the cam angle signal detected by the cam angle sensor; a phase control section that controls rotation of the electric motor in a direction that reduces a deviation between a target phase acquired from an external source and the actual phase; and a signal calibration section that, when it is determined that the detection timing of the cam angle signal deviates from an appropriate timing and is therefore inappropriate, sets an interpolated signal of the appropriate detection timing in place of the inappropriate signal determined to be inappropriate.

2. the cam angle sensor includes a rotor that rotates integrally with the camshaft and has a set number of teeth on its outer periphery, and a sensor unit that detects one edge of the teeth in the rotation direction as the camshaft rotates, 2. The valve timing control device according to claim 1, wherein the signal calibration unit stores the detection timing of the cam angle signal detected by the cam angle sensor when the camshaft rotates at least once while the actual phase is fixed, and performs identification processing that enables identification of the improper signal from the cam angle signal based on the stored detection timing.

3. the phase adjustment mechanism has a configuration in which an output shaft of the electric motor rotates in the same direction as a rotation direction of the camshaft at a speed equal to that of the camshaft, thereby fixing the actual phase, and adjusting the actual phase by making the rotation speed of the output shaft of the electric motor different from the rotation speed of the camshaft, 2. The valve timing control device according to claim 1, wherein the signal calibration unit stores the rotational speed signal of the output shaft of the electric motor for each unit time in a time domain in which the internal combustion engine is operated, the electric motor is driven to fix the actual phase, and the camshaft rotates at least once, and performs an identification process to identify, as the improper signal, a cam angle signal corresponding to a rotational speed signal at the stored detection timing in which a difference between rotational speeds of a comparison target is larger or smaller than a predetermined value.

4. the signal calibration unit performs machine learning to set an area where the improper signal exists as an NG area that can be identified by the crank angle signal by executing the identification process as needed at a timing when the actual phase is fixed while the internal combustion engine is in operation, and updates, after the machine learning, determination map data having a data structure that can identify an NG area determined by the number of cylinders and cam torque of the internal combustion engine using the crank angle signal and the previous actual phase; 4. The valve timing control device according to claim 2, wherein when the phase control unit performs phase control, if it is determined that the detection timing of the cam angle signal specified by the crank angle signal and the actual phase is included in the NG region, the interpolation signal can be set in place of the improper signal included in the NG region.

5. a drive-side rotor that rotates synchronously with a crankshaft of an internal combustion engine; a driven-side rotor that rotates integrally with a camshaft for opening and closing valves of the internal combustion engine; a phase adjustment mechanism that sets the relative rotational phase between the drive-side rotor and the driven-side rotor around a rotation axis by driving rotation of an electric motor; a phase sensing unit that acquires the relative rotational phase; and a phase control unit that controls the electric motor to set the relative rotational phase based on the result acquired by the phase sensing unit; the phase sensing unit includes a crank angle sensor that detects a rotation angle from a rotation reference when the crankshaft rotates, and a cam angle sensor that detects a cam angle signal for each of a plurality of preset rotation angles when the camshaft makes one rotation, the phase control unit includes an actual phase acquisition section that acquires the relative rotational phase as an actual phase based on the crank angle signal detected by the crank angle sensor and the cam angle signal detected by the cam angle sensor; a phase control section that controls rotation of the electric motor in a direction that reduces a deviation between an externally acquired target phase and the actual phase; and a signal calibration section that, when it is determined that the detection timing of the cam angle signal deviates from an appropriate timing and is therefore inappropriate, changes the detection timing of the improper signal and the appropriate signal in a direction that reduces the difference in detection timing between the improper signal determined to be inappropriate and the appropriate signal determined to be appropriate.

6. a drive-side rotor that rotates synchronously with a crankshaft of an internal combustion engine; a driven-side rotor that rotates integrally with a camshaft for opening and closing valves of the internal combustion engine; a phase adjustment mechanism that sets the relative rotational phase between the drive-side rotor and the driven-side rotor around a rotation axis by driving rotation of an electric motor; a phase sensing unit that acquires the relative rotational phase; and a phase control unit that controls the electric motor to set the relative rotational phase based on the result acquired by the phase sensing unit; the phase sensing unit includes a crank angle sensor that detects a rotation angle from a rotation reference when the crankshaft rotates, and a cam angle sensor that detects a cam angle signal for each of a plurality of preset rotation angles when the camshaft makes one rotation, When the detection timing of the cam angle signal is determined to be inappropriate because it deviates from the appropriate timing, the valve timing control device notifies an engine control unit that controls the internal combustion engine of the inappropriate timing, and in response to this notification, the engine control unit changes the ignition timing and the air amount calculation method.

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