Control device of a valve opening / closing timing control mechanism

Abstract

Control device (50) of a valve opening / closing timing control mechanism (VT) configured to have a drive-side rotating body (21) configured to rotate synchronously with the rotation of a crankshaft (1) of an internal combustion engine (E); an output-side rotating body (22) configured to rotate integrally with a camshaft (7) to open or close a valve (Va, Vb) that opens or closes a combustion chamber; a stopper unit (R) configured to determine a mechanical operating limit on one side with the furthest lagging angle and a mechanical operating limit on one side with the furthest leading angle of the driven-side rotating body with respect to the driven-side rotating body; and an electric motor (M) configured to control a relative rotational phase between the drive-side rotating body and the driven-side rotating body, the control device with: a phase controller (52) configured to control the electric motor to reduce, when a target phase (Tp) is set, any deviation between the target phase and a current first actual phase (Tx) detected by a phase sensing unit which detects the relative rotational phase, and to reduce the power supplied to the electric motor as the deviation decreases; and a control target setting unit (53) configured to set, instead of the target phase, a first target phase (T1) which is shifted from the target phase to one side of the first actual phase by a specified angle in an operating direction in which the deviation is reduced when the target phase is set to a phase with the furthest lagging angle or a phase with the furthest leading angle, which are an operating limit of the stopper unit, wherein the phase controller performs a first phase control, which is a phase control to reduce a deviation between the specified first target phase and the current first actual phase, wherein, if it is determined that the relative rotation phase reaches the first target phase by executing the first phase control, the control target setting unit sets the target phase to a second target phase (T2) instead of the first target phase, and the phase controller executes a second phase control, which is a phase control to reduce a deviation between the specified second target phase and an actual second phase, and wherein, After it is determined that the relative rotation phase reaches the second target phase by executing the second phase control, the control target setting unit sets a third target phase (T3) instead of the second target phase, which is shifted from the target phase to a side opposite the first actual phase by a predetermined angle in the operating direction where the deviation is reduced, and the phase controller executes a third phase control, which is a phase control to reduce a deviation between the set third target phase and an actual third phase.

Description

Technical field

[0001] This disclosure relates to a control device of a valve opening / closing timing control mechanism that controls the opening / closing time of a valve of a combustion chamber of an internal combustion engine by means of an electric motor. Discussion of the state of the art

[0002] JP 2011 - 80 431 A discloses that an electric motor is controlled by feedback such that the rotation angle converges to the desired rotation angle (normal control). Furthermore, feedback control (F / B control) of the electric motor is implemented such that the rotation angle converges to a minimum / maximum target end position. In this case, the electric motor is driven at a predetermined high speed (first speed) or higher.

[0003] Furthermore, JP 2016 - 89 683 A discloses an input-side and an output-side rotary body in connection with a valve opening / closing timing control mechanism.

[0004] DE 10 2009 037 484 A1 discloses that an actual phase angle is to be identical to a first target phase angle and that the first target phase angle is shifted to a second target phase angle when a valve mechanism is pressed against a stop.

[0005] As a valve opening / closing timing control mechanism with the configuration described above, JP 2015 - 132 178 A (Reference 1) discloses a technology comprising a drive-side rotary body (driving rotary body in the document) that rotates synchronously with a crankshaft of an internal combustion engine, an output-side rotary body (driven rotary body in the document) that rotates integrally with a camshaft that opens and closes a combustion chamber of the internal combustion engine, and an electric motor that establishes a relative rotational phase between the rotary bodies, and further comprising a control unit (control unit in the document) that controls the electric motor.

[0006] Reference 1 incorporates a stopper structure that halts the shift in the relative rotational phase through mechanical contact, even when the relative rotational phase of the driven-side rotating body reaches one of its most lagging or leading angles relative to the driven-side rotating body. When control is then applied to fix the relative rotational phase to the most lagging or leading angle, a control mechanism is implemented to reduce the contact velocity within the stopper structure by repeating the second and third excitations during an on / off cycle following the initial excitation by the control unit.

[0007] As described in Reference 1, the technology with a stopper structure is commonly used to determine an operating limit when the relative rotational phase between the drive-side rotating body and the driven-side rotating body reaches its furthest lagging angle, and when the relative rotational phase reaches its furthest leading angle.

[0008] In the internal combustion engine, the phase of the relative rotation can, for example, be set to the furthest lagging angle based on the operating state of the engine, and when the setting is controlled in this way, if the phase of the relative rotation is shifted at a high speed, a mechanical impulse noise in the range of a stopper can be generated.

[0009] For example, in a case where the control system can specify a control mode to reduce a voltage supplied to the electric motor when a deviation of the relative rotational phase is smaller than with PID control, for example by using an electric motor whose speed increases proportionally to an increase in the supplied voltage, such as a brushless DC motor, it is assumed that it is possible to match the speed of the electric motor to the speed of the camshaft at the time when the relative rotational phase reaches the furthest lagging angle, and consequently reduce an impact in the stopper.

[0010] Considering a delay in detection by a sensor that measures the relative rotational phase between the drive-side and driven-side rotating bodies, and a delay in control by the controller, it is considered that the stopper may generate a pulse noise when a control target is the furthest lagging or the furthest leading angle. With such a control system generating a pulse noise, it is considered that the valve opening / closing timing control mechanism may be damaged, and that the control of the valve's opening / closing time may deteriorate.

[0011] Therefore, there is a need for a control device that does not generate impulse noise, even if a target phase is set to the furthest lagging or the furthest leading phase. Summary

[0012] A feature of a control device of a valve opening / closing timing control mechanism according to one aspect of this disclosure is that the valve opening / closing timing control mechanism is configured to have: an input-side rotating body configured to rotate synchronously with the rotation of a crankshaft of an internal combustion engine; an output-side rotating body configured to rotate integrally with a camshaft for opening or closing a valve that opens or closes a combustion chamber; a stopper unit configured to determine a mechanical operating limit on one side with the furthest lagging angle and a mechanical operating limit on one side with the furthest leading angle of the output-side rotating body with respect to the input-side rotating body;and an electric motor configured to control a relative rotational phase between the drive-side rotating body and the driven-side rotating body, and the control device comprises: a phase controller configured to control the electric motor to reduce, when a target phase is specified, any deviation between the target phase and an actual first phase detected by a phase sensing unit which detects the relative rotational phase, and to reduce the power supplied to the electric motor as the deviation decreases;and a control target setting unit configured to set, instead of the target phase, a first target phase which is shifted from the target phase to one side of the first actual phase by a specified angle in an operating direction in which the deviation is reduced when the target phase is set to a phase with the furthest lagging angle or a phase with the furthest leading angle, which are an operating limit of the stopper unit, wherein the phase controller performs a first phase control which is a phase control to reduce a deviation between the specified first target phase and the actual first actual phase.

[0013] If, according to this characteristic configuration, for example, the phase with the furthest lagging angle is defined as the target phase, the control target setting unit defines, instead of the target phase, the first target phase, which is shifted from the target phase to the side of the first actual phase (side of the leading angle), by the defined angle in the operating direction in which the deviation is reduced. Additionally, the phase controller performs the first phase control to reduce the deviation between the first target phase and the current first actual phase, which is detected by the phase sensing unit.Even if there is a delay in detection by the phase detection unit or a delay in control by the phase controller, it is possible to prevent mechanical contact in the stopper unit by reducing the displacement velocity before the relative rotation phase reaches the first target phase. Alternatively, even if contact does occur, it is possible to reduce the impact caused by the contact in the stopper unit. This control can also be implemented in the same way to reduce the impact even if the target phase is set to the phase with the most leading angle.

[0014] Therefore, the control device is configured not to generate any impulse noise, even when the target phase is set to the phase with the furthest lagging angle or the phase with the furthest leading angle.

[0015] A disclosed feature of the control device is that, when it is determined that the relative rotational phase has reached the first target phase by performing the first phase control, the control target setting unit sets the target phase to a second target phase instead of the first target phase, and the phase controller can perform a second phase control, which is a phase control to reduce a deviation between the set second target phase and an actual second phase.

[0016] Since, according to this configuration, the displacement speed of the relative rotation phase is greatly reduced when the relative rotation phase reaches the first target phase by executing the first phase control, and in this state the target phase is set to the second target phase as an initial control target, the deviation at the time of starting the second phase control is small, and even when the relative rotation phase reaches the second target phase (original control target) by executing the second phase control, mechanical contact in the stopper unit can be carried out slowly, and the generation of impulse noise can be prevented.

[0017] Another disclosed feature of the control device is that, after it has been determined that the relative rotational phase has reached the second target phase by performing the second phase control, the control target setting unit sets a third target phase instead of the second target phase. This third target phase is shifted from the target phase to a side opposite the first actual phase by a predetermined angle in the direction of operation, where the deviation is reduced. The phase controller can then perform a third phase control, which is a phase control to reduce a deviation between the set third target phase and an actual third phase.

[0018] According to this configuration, by setting the third target phase on the downstream side of the original target phase in the operating direction where the deviation is reduced, after the relative rotational phase has reached the original control target by performing the second phase control, the electric motor is driven to continuously shift the relative rotational phase in the direction in which the contact state is maintained by performing the third phase control, even in a state where the stopper unit is in a mechanical contact state. As a result, the mechanical contact state in the stopper unit is maintained, and even if a fluctuating cam torque is acting, no contact noise is generated in the stopper unit.

[0019] Another feature of the control device is that the second target phase is the phase with the furthest lagging angle or the phase with the furthest leading angle. Brief description of the drawings

[0020] The foregoing and additional features and characteristics of this disclosure will become clearer from the following detailed description in relation to the associated drawings, in which: Fig. Figure 1 is a cross-sectional view of an engine; Fig. 2 is a block diagram of a control device; Fig. Figure 3 is a cross-sectional view of a valve opening / closing timing control mechanism; Fig. Figure 4 is a cross-sectional view along line IV-IV of Fig. 3; Fig. Figure 5 is a cross-sectional view along line VV of Fig. 3; Fig. Figure 6 is a cross-sectional view along line VI-VI of Fig. 3; Fig. Figure 7 is a perspective view of the individual parts of the valve opening / closing timing control mechanism; Fig. Figure 8 is a block diagram of a control unit; Fig. Figure 9 is a flowchart of a phase control routine; Fig. 10 is a flowchart of the operational limit control; and Fig. Figure 11 is a diagram that represents a positional relationship between a regulating unit and a contact piece in the operating limit control. Detailed description

[0021] An exemplary embodiment disclosed herein is described below with reference to the associated drawings. [Basic configuration]

[0022] An E-engine, as an internal combustion engine, is like in Fig. 1 is configured as shown, and a motor control device A, which controls the motor E, is as shown in Fig. 2 shown configured.

[0023] The engine control device A comprises an engine control unit 40, which functions as an ECU, and a phase control unit 50 (an example of a control device for a valve opening / closing timing control mechanism), which also functions as an ECU. The engine control unit 40 performs the starting of the engine E, the management of the engine E in an operating state, and the stopping of the engine E. The phase control unit 50 controls a phase control motor M (an example of an electric motor) of a valve opening / closing timing control mechanism VT to determine the opening / closing time (valve time) of an inlet valve Va by the valve opening / closing timing control mechanism VT. [Motor]

[0024] As in the Fig. 1 and Fig. Figure 3 shows that the engine E (an example of an internal combustion engine) is provided in a vehicle such as a passenger car. The engine E is configured in a four-stroke form such that a cylinder head 3 is connected to an upper section of a cylinder block 2 which carries a crankshaft 1, wherein a piston 4 is slidably received in each of a plurality of cylinder bores formed in the cylinder block 2, and the piston 4 is connected to the crankshaft 1 via a connecting rod 5.

[0025] Engine E contains cylinder #1, cylinder #2, cylinder #3 and cylinder #4 (represented as #1, #2, #3 and #4 in Fig. 3) arranged from one end to the other end.

[0026] The cylinder head 3 is provided with the intake valve Va and an exhaust valve Vb. An intake camshaft 7, which controls the intake valve Va, and an exhaust camshaft 8, which controls the exhaust valve Vb, are provided in an upper section of the cylinder head 3. A timing belt 6 is wound around an output pulley section 1P of the crankshaft 1, a timing pulley section 21P of a drive housing 21 of the valve opening / closing timing mechanism VT, and a drive pulley section 8P of the exhaust camshaft 8.

[0027] The cylinder head 3 is equipped with an injector 9, which injects fuel into a combustion chamber, and a spark plug 10. The cylinder head 3 is connected to an intake manifold 11, which supplies air to the combustion chamber via the intake valve Va, and to an exhaust manifold 12, which releases combustion gases from the combustion chamber via the exhaust valve Vb. [Basic configuration: configuration of the sensors]

[0028] The motor E is, as in the Fig. 1 and Fig. The motor E, shown in Figure 2, is equipped with a starter motor 15 that drives and rotates the crankshaft 1 and is also equipped with a crank angle sensor 16 located near the crankshaft 1, which is capable of detecting the angle of rotation and the number of rotations per unit of time. The motor E is equipped with a cam angle sensor 17, which is capable of detecting the rotational phase of the intake camshaft 7.

[0029] A phase detection unit is formed from the crank angle sensor 16, the cam angle sensor 17 and a phase calculation unit 51, as shown in Fig. Figure 8 shows. Additionally, a permanently assigned sensor that detects a relative rotational phase between the drive housing 21 (drive-side rotating body) and an internal rotor 22 (output-side rotating body) can be used as the phase detection unit.

[0030] If, according to this configuration, the engine E is started by driving the starter motor 15, the opening / closing time (valve timing) can be obtained by obtaining a relative rotational phase of the valve opening / closing timing control mechanism VT based on a detection result by the crank angle sensor 16 and a detection result by the cam angle sensor 17.

[0031] In engine E, cylinder differentiation is performed by the engine control unit 40 based on a detection signal from the crankshaft angle sensor 16 and a detection signal from the camshaft angle sensor 17. That is, as in Fig. Figure 2 shows that the crankshaft angle sensor 16 is configured such that several teeth 16T are provided on the outer circumference of a disc section 16D, which rotates integrally with the crankshaft 1, and a crankshaft angle sensor unit 16S is provided to detect the several teeth 16T. A reference point 16n, at which no teeth 16T are provided, is formed at two positions on the outer circumference of the disc section 16D. The reference point is designed to coincide with the top dead center of a given cylinder (e.g., cylinder #1).

[0032] The disc section 16D and the teeth 16T are formed in one piece from a magnetic material, and a crank sensor unit 16S of a sensor type is used. Thus, the crank sensor unit 16S detects each of the several teeth 16T with respect to the reference point 16n at the time of rotation of the crankshaft 1, and the rotation angle of the crankshaft 1 (the angle about the reference point 16n) is determined by counting the number of detection times in the phase control unit 50.

[0033] As in Fig. As shown in Figure 2, the cam angle sensor 17 is configured such that four sector-shaped detection areas 17T are provided on the outer circumference of a rotating body 17D, which rotates integrally with the intake camshaft 7 and an intake cam sensor unit 17S, which detects the detection areas 17T. Additionally, the four detection areas 17T have different lengths (circumference lengths), each divided into four equally spaced sections around the entire circumference of the rotating body 17D, thus enabling differentiation of the four cylinders.

[0034] The rotating body 17D and the sensing areas 17T are made of a magnetic material, and an inlet cam sensor unit 17S of a sensor type is used. When the beginning end (detection of the rising edge) of the sensing area 17T is detected by the inlet cam sensor unit 17S according to the rotation of the inlet camshaft 7, the counting of a clock signal generated in the phase control unit 50 is started, and when the end end (detection of the falling edge) of the sensing area 17T is detected, the counting is stopped, so that a differentiation of the cylinders based on the count value (integrated value) at the time of termination is possible.

[0035] In particular, the cam angle sensor 17 is also configured to detect the opening / closing time (valve timing) of the valve opening / closing timing control mechanism VT. In other words, considering, for example, a state in which the valve opening / closing timing control mechanism VT is at its furthest lagging angle, the count value of the crank angle sensor 16 at the detection time, when the end of a preset detection range 17T is detected among the four detection ranges 17T, is a value corresponding to the phase with the furthest lagging angle.

[0036] Additionally, if the relative rotational phase (the relative rotational phase between the drive housing 21 and the inner rotor 22, shown in Fig. 3) If the valve opening / closing timing control mechanism VT is shifted from a phase with the furthest lagging angle to an intermediate phase, the count value of the crank angle sensor 16 also changes at the detection time described above, so that the detection of the opening / closing time from the amount of change (difference / offset value) is possible.

[0037] Additionally, as in the Fig. Figures 4 to 6 show that the most lagging angle is a phase that forms a boundary when the relative rotational phase of the valve opening / closing timing mechanism VT is shifted in a lagging angle direction Sb. Furthermore, a phase that forms a boundary when the relative rotational phase is shifted in a leading angle direction Sa is referred to as a phase with the most leading angle. [Valve opening / closing timing mechanism]

[0038] As in the Fig. Figures 3 to 7 comprise the valve opening / closing timing control mechanism VT, the drive housing 21 (an example of the drive-side rotating body) and the inner rotor 22 (an example of the driven-side rotating body), and are provided with a phase adjustment unit which determines the relative rotational phase by driving the phase control motor M (an example of the electric motor). A brushless DC motor is used as the phase control motor M, so that the motor speed increases with increasing applied voltage.

[0039] The drive housing 21 is arranged coaxially to a rotational axis X of the intake camshaft 7 and is formed on its outer circumference with the timing belt pulley section 21P. The inner rotor 22 is enclosed by the drive housing 21 so that it is rotatable relative to it and is connected and fastened to the intake camshaft 7 by a connecting screw 23. The phase adjustment unit is arranged between the drive housing 21 and the inner rotor 22, and a front plate 24 is positioned so that it covers an opening section of the drive housing 21 and is fastened to the drive housing 21 by a plurality of fastening screws 25.

[0040] The entire valve opening / closing timing control mechanism VT rotates in a direction that Fig. 4 and Fig. The direction of rotation S shown in Figure 5 is driven by a driving force from the control belt 6. Furthermore, a direction in which the relative rotational phase of the inner rotor 22 with respect to the drive housing 21 is shifted in the same direction as the direction of rotation S by a driving force from the phase control motor M is called the leading angular direction Sa, and the shift in the opposite direction is called the lagging angular direction Sb.

[0041] Additionally, the intake air volume at the intake valve Va is increased by shifting the relative rotational phase in the leading angle direction Sa. Conversely, the intake air volume at the intake valve Va is reduced by shifting the relative rotational phase in the lagging angle direction Sb. [Valve opening / closing timing mechanism: Phase setting unit]

[0042] As in the Fig. As shown in Figures 3 to 7, the phase adjustment unit consists of the inner rotor 22, a ring gear 26 formed on the inner circumference of the inner rotor 22, an internal gear 27, an eccentric cam body 28, and a connecting unit J. The ring gear 26 has a plurality of internal teeth 26T around the axis of rotation X on the inner circumference of the inner rotor 22. The internal gear 27 has a plurality of external teeth 27T on its outer circumference and is arranged coaxially with an eccentric axis Y, which is parallel to the axis of rotation X, such that the external teeth 27T on a section of the axis engage with the internal teeth 26T on a section of the ring gear 26.

[0043] As in Fig. 6 and Fig. As shown in Figure 7, a stop unit R is provided in particular to determine a mechanical operating limit when the relative rotational phase of the inner rotor 22 with respect to the drive housing 21 reaches the phase with the most lagging angle and when the relative rotational phase reaches the phase with the most leading angle. The stop unit R is formed from a pair of regulating sections 21a, which project in the inner circumferential direction from the drive housing 21, and a contact piece 22a, which is formed at the end of the inner rotor 22 at a position where it can come into contact with the regulating section 21a. In addition, the inner rotor 22 is formed with a compensating device 22b at a position opposite the contact piece 22a, with the axis of rotation X arranged between them.

[0044] In the phase setting unit, the number of teeth of the outer teeth 27T of the internal gear 27 is only one less than the number of teeth of the inner teeth 26T of the ring gear 26.

[0045] Furthermore, the connecting unit J is configured as an Oldham coupling, which prevents the relative rotation between the drive housing 21 and the inner rotor 22, while allowing the inner rotor 22 to be displaced in the direction perpendicular to the axis of rotation X in relation to the drive housing.

[0046] The eccentric cam body 28 is mounted by a first bearing 31 relative to the front plate 24 so that it rotates coaxially with the axis of rotation X. The eccentric cam body 28 is formed integrally with an eccentric cam surface 28A, which is centered on the eccentric axis Y and has a position parallel to the axis of rotation X. The internal gear 27 is rotatably mounted relative to the eccentric cam surface 28A via a second bearing 32. Additionally, a spring element 29 is inserted in a recess formed in the eccentric cam surface 28A, and a compressive force of the spring element 29 acts on the internal gear 27 via the second bearing 32.

[0047] The eccentric cam body 28 has an overall tubular shape and is formed on its inner circumference with a pair of engagement grooves 28B in a position parallel to the axis of rotation X. Thus, some of the outer teeth 27T of the internal gear 27 engage with some of the inner teeth 26T of the ring gear 26.

[0048] The connecting unit J comprises a connecting element 33, which is formed by pressing a plate. A pair of engagement arms 33A formed on the connecting element 33 engage with engagement grooves 21G in the drive housing 21, and a pair of engagement recesses 33B formed in the connecting element 33 engage with engagement projections 27U of the internal gear 27.

[0049] Meanwhile, the connecting element 33 has a structure in which its central section is formed in a ring shape, the pair of engagement arms 33A project outwards from the annular central section, and the pair of engagement recesses 33B are designed to be connected to the space in the annular central section.

[0050] In the connecting unit J, the connecting element 33 is displaceable in a straight direction, which connects the pair of engagement grooves 21G in the drive housing 21, and the internal gear 27 is displaceable in a straight direction, which connects the pair of engagement projections 27U with respect to the connecting element 33.

[0051] The phase control motor M is supported by the motor E and is provided with an engagement pin 34 which has a position perpendicular to an output shaft Ma, and the engagement pin 34 is inserted into the engagement groove 28B in the inner circumference of the eccentric cam body 28.

[0052] Considering an operating mode in a state where the motor E stops when the eccentric cam body 28 is rotated by the driving force of the phase control motor M, the eccentric cam surface 28A rotates about the axis of rotation X, and the internal gear 27 begins to rotate about the axis of rotation X. Since the engagement position between the outer teeth 27T of the internal gear 27 and the inner teeth 26T of the ring gear 26 shifts along the inner circumference of the ring gear 26 during the rotation, a force acts on the internal gear 27 to rotate it about the eccentric axis Y.

[0053] If the internal gear 27 rotates only once, a rotational force (torque on the axis) acts, which attempts to rotate the ring gear 26 relative to the internal gear 27 by an angle (angle corresponding to one tooth) that corresponds to a difference (difference in the number of teeth) between the number of internal teeth 26T of the ring gear 26 and the number of external teeth 27T of the internal gear 27, between the internal gear 27 and the ring gear 26.

[0054] Since, as described above, the connecting unit J has a structure for regulating the rotation of the internal gear 27 in relation to the drive housing 21, the internal gear 27 does not rotate in relation to the drive housing 21, the ring gear 26 rotates in relation to the drive housing 21 due to the rotational force acting on the internal gear 27, and the inner rotor 22 rotates integrally with the ring gear 26, so that an adjustment of the rotational phase of the inlet camshaft 7 in relation to the drive housing 21 is realized.

[0055] In particular, if the internal gear 27 rotates only once around the axis of rotation X, since the inlet camshaft 7 is rotated by an angle relative to the drive housing 21 which corresponds to the difference (difference in the number of teeth) between the number of outer teeth 27T of the internal gear 27 and the number of inner teeth 26T of the ring gear 26, a setting with a large reduction ratio is achieved. [Overview of phase setting]

[0056] When the phase adjustment of the valve opening / closing timing control mechanism VT is performed, the phase control unit 50 drives and rotates the output shaft Ma of the phase control motor M in the same direction as the inlet camshaft 7 and at the same speed as the rotational speed of the inlet camshaft 7, thereby maintaining the relative rotational phase between the drive housing 21 and the inner rotor 22.

[0057] Additionally, the phase control unit 50 shifts the relative rotational phase in the leading angle direction Sa or in the lagging angle direction Sb by increasing or decreasing the speed of the phase control motor M relative to the speed of the intake camshaft 7. This control of the relative rotational phase, as described above, is implemented by reference to the relative rotational phase of the valve opening / closing timing control mechanism VT based on information from the crankshaft angle sensor 16 and the camshaft angle sensor 17, and by providing feedback of this relative rotational phase. [Motor control unit and phase control unit]

[0058] The engine control unit 40 is provided with an engine control unit configured with software to control the engine E from start to stop by controlling the starter motor 15, the injector 9 and the spark plug 10.

[0059] As in Fig. As shown in Figure 8, the phase control unit 50 comprises a phase calculation unit 51, a phase controller 52, a control target setting unit 53, a PWM setting unit 54 and a power control unit 55.

[0060] Although the phase control unit 50 contains the phase calculation unit 51, the phase controller 52, the control target setting unit 53 and the PWM setting unit 54 configured with software, these components can be configured with hardware, such as logic or memory, or can be configured by combining software and hardware.

[0061] The phase calculation unit 51 calculates a current relative rotational phase between the drive housing 21 (drive-side rotating body) and the inner rotor 22 (output-side rotating body) by obtaining detection signals from the cam angle sensor 17 and the crank angle sensor 16 and provides the calculated current relative rotational phase to the phase controller 52. The control target setting unit 53 defines a target relative rotational phase by obtaining target phase information from an external source (e.g., the motor control unit 40) and provides the target phase to the phase controller 52 as a control target.

[0062] The phase controller 52 receives a deviation from the control target, which is obtained from the control target setting unit 53, simultaneously with the current relative rotational phase between the drive housing 21 and the inner rotor 22 being obtained from the phase calculation unit 51, and sets the target power accordingly. Based on the target power from the phase controller 52, the PWM setting unit 54 outputs a PWM control signal to the power controller 55, and the power controller 55 supplies power to the phase control motor M. Additionally, the PWM setting unit 54 controls the power by pulse width modulation (PWM), which switches the power supplied by a power supply, for example via a switching element, on or off in a fixed cycle, and sets the on-time during the cycle.

[0063] In the phase control unit 50, a control mode is defined in the phase controller 52 to increase the power (voltage and current) supplied to the phase control motor M with increasing deviation, and to reduce the power supplied to the phase control motor M with decreasing deviation, by performing proportional-integral differential control (PID).

[0064] The control mode in the phase controller 52 is not limited to PID control, but can be configured to perform, for example, only P control, only I control or only D control.

[0065] Additionally, in the valve opening / closing timing control mechanism VT, if the relative rotational phase is maintained during the operation of motor E, a control is performed to rotate the phase control motor M at the same speed as the intake camshaft 7. Therefore, if, for example, the deviation from the current relative rotational phase is obtained and the control target and the set power corresponding to the deviation are determined, the power of a value obtained by adding or subtracting a power corresponding to the deviation to or from the power that rotates the phase control motor M at the same speed as the intake camshaft 7 is supplied to the phase control motor M. [Regulatory form]

[0066] When a new target phase is acquired, the phase control unit 50 executes a phase control routine, which is shown in the flowchart in Fig. 9 is shown.

[0067] As described above, in the valve opening / closing timing control mechanism VT, when the relative rotational phase is the phase with the furthest lagging angle or the phase with the furthest leading angle, the regulating section 21a and the contact piece 22a, which form the stopper unit R, come into contact with each other. If the contact state is an operating limit and a target phase is not the operating limit (step #101), a deviation between the current relative rotational phase, detected by the phase sensing sensor, and the target phase is referenced, and phase control is performed, in which the phase controller 52 determines the power to be supplied to the phase control motor M based on the referenced deviation, until convergence is achieved (steps #102 to #104).

[0068] Additionally, if in step #101 it is determined that the target phase is the operating limit (the phase with the furthest lagging angle or the phase with the furthest leading angle), the operating limit control (step #200) is executed.

[0069] In the operational limit control (step #200), the control target setting unit 53 first defines, as shown in the flowchart in Fig. Figure 10 shows a first target phase T1 fixed, and the phase controller 52 drives the phase control motor M to converge the deviation between the current relative rotation phase detected by the phase sensing sensor and the first target phase T1, and continues driving until the first phase control converges (steps #201 to #203). Here, “the deviation converges” means that the relative rotation phase reaches within ±3° KW with respect to the target phase, and “the phase control converges” means convergence of the phase control according to the convergence of the deviation.

[0070] The top level (a) of Fig. Figure 11 represents a current first actual phase Tx, in which the relative rotation phase is not at the operating limit. Fig. 11 represents the second stage (b) from the top, a target phase Tp, which is the operating limit (e.g., the phase with the greatest lagging angle). The in Fig. The current first actual phase Tx shown in 11 represents an arbitrary relative rotation phase before the phase control is started according to the present embodiment.

[0071] Additionally, the third stage (c) (middle stage) represents the first target phase T1. As shown, the control target setting unit 53 sets the first target phase T1 to an angle by which the relative rotation phase is oriented by a setting angle Tc from the target phase Tp to the side of the first actual phase (clockwise). Fig. 11) is shifted in an operating direction in which the deviation in the phase control with respect to the target phase Tp is reduced. When the relative rotational phase from the first actual phase Tx is shifted by the phase control to the first target phase T1 and the phase control converges, a gap is necessarily formed between the contact piece 22a and the regulating section 21a of the stopper unit R. It should also be noted that the first actual phase Tx is located on the upstream side of the first target phase T1 (clockwise). Fig. 11).

[0072] Since, as described above, the phase controller 52 sets the target power according to the deviation between the current first actual phase, which is obtained from the phase sensing unit, and the target phase when the first phase control converges, the relative speed between the drive housing 21 and the inner rotor 22 is extremely low.

[0073] Next (after the first phase control has converged), the target setter 53 sets a second target phase T2, and the phase controller 52 drives the phase control motor M to converge the deviation between the current relative rotation phase (first target phase T1) detected by the phase sensing sensor and the second target phase T2, and continues driving until the second phase control has converged (steps #204 to #206).

[0074] The fourth stage (d) (second stage from the bottom) in Fig. 11 represents the second target phase T2. The control target setting unit 53 sets the second target phase T2 to the same rotational phase as the target phase Tp. Additionally, since the second phase control is executed after the first phase control has converged and the angular difference between the second target phase T2 and the first target phase T1 (an example of a current second actual phase) is small, the deviation is small even immediately after the second phase control is started. Therefore, the relative speed between the drive housing 21 and the inner rotor 22 does not increase, the contact piece 22a and the regulating section 21a of the stopper unit R do not come into contact at high speed, and the generation of impulse noise is also prevented because no impact occurs at the time of contact.

[0075] Then (after the second phase control has converged) the control target setting unit 53 sets a third target phase T3, and the phase controller 52 drives the phase control motor M to converge the deviation between the current relative rotation phase (the second target phase T2) detected by the phase detection sensor and the third target phase T3 (steps #207 and #208).

[0076] The fifth stage (e) (the lowest stage) of Fig. 11 represents the third target phase T3. The control target setting unit 53 sets the third target phase T3 to an angle by which the relative rotation phase is by a predetermined angle Td from the second target phase T2 to the side opposite the first actual phase (counterclockwise). Fig.11), is shifted in an operating direction in which the deviation in the second phase control is reduced with respect to the second target phase T2 (equal to the target phase Tp: an example of a current third actual phase).

[0077] Although the third phase control does not converge because the relative rotational phase reaches a mechanical limit where the contact piece 22a and the regulating section 21a of the stopper unit R come into contact, the drive force of the phase control motor M continues to maintain a state in which the contact piece 22a and the regulating section 21a are in contact. Therefore, the phenomenon of the contact piece 22a and the regulating section 21a being separated is prevented, even when a fluctuating cam torque is acting, and the generation of impulse noise is also prevented. [Work effects of the embodiment example]

[0078] In this way, if the target phase Tp is set to determine the relative rotation phase to the phase with the furthest lagging angle or the phase with the furthest leading angle, it is possible to converge the control in a state in which the regulating section 21a and the contact piece 22a of the stopper unit R do not come into contact with each other by setting the first target phase T1 instead of the target phase Tp to perform the first phase control.

[0079] Next, as the regulating section 21a and the contact piece 22a of the stopper unit R are slowly brought into contact by setting the second target phase T2 to execute the second phase control, it is possible to prevent the generation of pulse noise. Additionally, after the second phase control has converged, it is possible to maintain the state in which the regulating section 21a and the contact piece 22a of the stopper unit R are in contact by setting the third target phase T3 to execute the third phase control, thus preventing the generation of pulse noise caused by repeated contact between the regulating section 21a and the contact piece 22a.

[0080] This disclosure can be applied to a valve opening / closing timing control mechanism that controls the opening / closing time of a valve of a combustion chamber of an internal combustion engine by means of an electric motor.

[0081] The principles, preferred embodiment, and operating mode of the present invention have been described in the preceding description. However, the invention to be protected is not limited to the disclosed specific embodiments. Furthermore, the embodiments described herein are to be considered illustrative and not limiting. Variations and modifications may be made by others, and equivalents may be used, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, modifications, and equivalents that fall within the spirit and scope of protection of the present invention, as defined in the claims, are thereby encompassed.

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