WO2022249612A1 - Dispositif de commande pour mécanisme de distribution à programme variable et son procédé de commande - Google Patents

Dispositif de commande pour mécanisme de distribution à programme variable et son procédé de commande Download PDF

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Publication number
WO2022249612A1
WO2022249612A1 PCT/JP2022/008314 JP2022008314W WO2022249612A1 WO 2022249612 A1 WO2022249612 A1 WO 2022249612A1 JP 2022008314 W JP2022008314 W JP 2022008314W WO 2022249612 A1 WO2022249612 A1 WO 2022249612A1
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WIPO (PCT)
Prior art keywords
value
phase
motor
valve timing
variable valve
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PCT/JP2022/008314
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English (en)
Japanese (ja)
Inventor
雅貴 小須田
誠己 羽野
宣彦 松尾
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日立Astemo株式会社
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Publication of WO2022249612A1 publication Critical patent/WO2022249612A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D45/00—Electrical control not provided for in groups F02D41/00 - F02D43/00
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates to a control device and control method for a variable valve timing (VTC: Variable Valve Timing Control) mechanism.
  • VTC Variable Valve Timing Control
  • Patent Document 1 discloses phase feedback control in an internal combustion engine in which the rotation phase of the camshaft with respect to the crankshaft is brought closer to a target value by the rotation output of the motor.
  • the detected value of the rotation phase is periodically obtained based on the output signal of the crank angle sensor and the output signal of the cam angle sensor, and the detected value is periodically obtained based on the previously obtained detected value. It computes an estimate of the rotational phase during acquisition.
  • Patent Document 1 since the calculation constants used when calculating the estimated value of the rotational phase do not reflect individual differences and the ambient environment such as temperature, the estimated value of the rotational phase varies from the actual value. , it is assumed that the variable valve timing mechanism does not exhibit uniform responsiveness. Therefore, during phase feedback control, if the estimated value changes toward the target value slower than the actual value, the motor continues to rotate even though the actual value has reached the target value. This may lead to an overshoot in which the rotation phase exceeds the target value.
  • the present invention provides a control apparatus and control method for a variable valve timing mechanism that suppresses overshoot in which the rotation phase of the camshaft with respect to the crankshaft of an internal combustion engine exceeds a target value. With the goal.
  • control device and control method for a variable valve timing mechanism relate to control of a variable valve timing mechanism capable of changing the rotation phase of a camshaft with respect to a crankshaft of an internal combustion engine by the rotation output of a motor. , periodically acquires the detected value of the rotation phase based on the output signal of the crank angle sensor that detects the angular position of the crankshaft and the output signal of the cam angle sensor that detects the angular position of the camshaft, and detects the previously obtained detection value. Using the value as a reference, an estimated value of the rotation phase is calculated while the detected value is periodically acquired, and phase feedback control is performed by the motor so that the calculated estimated value approaches the target value. During this phase feedback control, The estimated value is calculated to change toward the target value faster than the actual value of the rotational phase.
  • control device and control method for the variable valve timing mechanism of the present invention it is possible to suppress the overshoot of the rotation phase of the camshaft with respect to the crankshaft of the internal combustion engine.
  • FIG. 1 is a schematic configuration diagram showing an example of a vehicle internal combustion engine according to a first embodiment
  • FIG. 4 is a time chart showing an example of signal patterns of a crank angle signal and a cam angle signal
  • FIG. 2 is a cross-sectional view showing an example of the structure of a variable valve timing mechanism
  • FIG. 4 is a cross-sectional view of the variable valve timing mechanism of FIG. 3 taken along the line AA
  • FIG. 4 is a cross-sectional view of the variable valve timing mechanism of FIG. 3 taken along line BB
  • FIG. 2 is a block diagram showing an example of a schematic configuration of an ECM and a VTC controller
  • FIG. 1 shows an example of a vehicle internal combustion engine provided with a variable valve timing mechanism as a first embodiment.
  • the internal combustion engine 1 is a vehicle internal combustion engine that generates power for a vehicle in which the internal combustion engine 1 is mounted, and an example thereof is a four-stroke spark ignition engine having multiple cylinders.
  • the internal combustion engine 1 has a cylinder block 2 formed with a cylinder 2a and a crankcase 2b, and a cylinder head 3 formed with an intake port 3a and an exhaust port 3b.
  • a piston 4 is fitted into the cylinder 2a so as to reciprocate, and a combustion chamber 5 is formed between the crown surface of the piston 4 and the lower surface of the cylinder head 3.
  • a water jacket 10c is formed in the wall around the cylinder 2a for circulating cooling water circulating between the internal combustion engine 1 and an external heat exchanger.
  • a crankshaft 6 is rotatably supported by the cylinder block 2 via a main bearing (not shown) in the crankcase 2b.
  • a connecting rod (connecting rod) 7 has an upper end rotatably connected to the piston 4 and a lower end rotatably connected to a position eccentric from the rotation axis of the crankshaft 6 so that the crankshaft 6 and the piston 4 are connected.
  • the opening of the intake port 3 a facing the combustion chamber 5 is opened and closed by an intake valve 8 supported by the cylinder head 3 .
  • the intake valve 8 reciprocates in the axial direction of the stem portion. do.
  • the head portion of the intake valve 8 opens and closes the opening of the intake port 3a facing the combustion chamber 5 in accordance with the rotation cycle of the intake camshaft 10 .
  • the opening of the exhaust port 3 b facing the combustion chamber 5 is opened and closed by an exhaust valve 9 supported by the cylinder head 3 .
  • the tappet portion of the exhaust valve 9 contacts the exhaust cam 13 on the outer periphery of the exhaust cam shaft 12 rotatably supported by the cylinder head 3
  • the exhaust valve 9 reciprocates in the axial direction of the stem portion. do.
  • the head portion of the exhaust valve 9 opens and closes the opening facing the combustion chamber 5 of the exhaust port 3b in accordance with the rotation period of the exhaust camshaft 12 .
  • the rotational output of the crankshaft 6 is transmitted to the intake camshaft 10 and the exhaust camshaft 12 via a timing chain, which will be described later.
  • the intake camshaft 10 and the exhaust camshaft 12 are arranged so that the rotational speed of the crankshaft 6 when the rotational output of the crankshaft 6 is transmitted is half the rotational speed of the crankshaft 6, that is, when the crankshaft 6 makes two revolutions.
  • the intake camshaft 10 and the exhaust camshaft 12 are configured to make one rotation.
  • An intake pipe 15 for introducing air from the outside of the vehicle to the internal combustion engine 1 is connected to the intake port 3a via an intake manifold 14 .
  • the exhaust port 3b is connected via an exhaust manifold 16 to an exhaust pipe 17 for guiding exhaust gas generated in the internal combustion engine 1 to the outside of the vehicle.
  • the exhaust pipe 17 incorporates a catalytic converter 18 supporting a catalyst such as a three-way catalyst for converting exhaust components.
  • a port injection type fuel injection valve 19 for injecting fuel into an intake port 3 a on the upstream side of the intake valve 8 is arranged in the cylinder head 3 .
  • a spark plug 20 for igniting and burning a mixture of fuel and air in the combustion chamber 5 is arranged in the cylinder head 3 so as to face the combustion chamber 5 .
  • the ignition plug 20 is connected to an ignition module 21 containing an ignition coil and a power transistor for controlling energization of the coil, and supplies ignition energy to the ignition plug 20 .
  • the internal combustion engine 1 sequentially performs four strokes, an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke, to form one cycle, and this cycle is repeated.
  • the intake stroke the intake valve 8 is opened and the piston 4 is lowered to suck air (air mixture) containing fuel into the combustion chamber 5 .
  • the compression stroke the air-fuel mixture in the combustion chamber 5 is compressed by closing the intake valve 8 and the exhaust valve 9 and moving the piston 4 up to the top dead center.
  • the combustion stroke the air-fuel mixture ignited by the ignition plug 20 burns, the combustion gas expands, and the piston 4 is pushed down to the bottom dead center.
  • the rotational inertia of the crankshaft 6 causes the piston 4 to rise and the exhaust valve 9 to open, thereby pushing out the combustion gas in the combustion chamber 5 toward the exhaust pipe 17 .
  • the variable valve timing mechanism 22 is a mechanism that continuously advances or retards the valve timing of the intake valve 8 by changing the rotation phase according to the rotation output of the motor 23 that is provided as an actuator.
  • the motor 23 a DC brush motor is used, although not limited thereto.
  • rotational phase of the intake camshaft 10 with respect to the crankshaft 6 is simply referred to as "rotational phase”.
  • the control device for the internal combustion engine 1 includes an engine control module (hereinafter referred to as "ECM") 24 and a VTC controller 25.
  • the ECM 24 has a function of controlling fuel injection by the fuel injection valve 19, ignition by the spark plug 20, and the like.
  • the VTC controller 25 has a function of controlling the variable valve timing mechanism 22 .
  • Both the ECM 24 and the VTC controller 25 incorporate a microcomputer including a processor such as a CPU (Central Processing Unit), a nonvolatile memory such as a ROM (Read Only Memory), and a volatile memory such as a RAM (Random Access Memory). .
  • Each microcomputer of the ECM 24 and VTC controller 25 has an input/output interface, through which various signals are input/output.
  • the ECM 24 and the VTC controller 25 are configured to communicate with each other via a communication circuit 26 such as a CAN (Controller Area Network).
  • a communication circuit 26 such as a CAN (Controller Area Network).
  • the ECM 24 controls fuel injection, ignition, etc. by reading the stored program of the non-volatile memory to the volatile memory and executing it by the processor while the microcomputer inputs the output signal of various sensors through the input / output interface. It has the function to Specifically, the ECM 24 generates and outputs driving signals for the fuel injection valve 19, the ignition module 21, and the like.
  • the ECM 24 calculates a target value TA of the rotation phase based on the operating state of the internal combustion engine 1 in addition to controlling fuel injection, ignition, etc., by executing a stored program by the processor, and transmits it via the communication circuit 26. , to transmit the target value TA to the VTC controller 25 .
  • the various sensors mentioned above include a flow rate sensor 27, a crank angle sensor 28, an accelerator opening sensor 29, a cam angle sensor 30, a water temperature sensor 31, an air-fuel ratio sensor 32, and the like.
  • the flow rate sensor 27 is a sensor that actually measures the intake air flow rate of the internal combustion engine 1 and outputs the measured value as an intake air amount signal QA.
  • the crank angle sensor 28 is a sensor that outputs a crank angle signal CRANK at each predetermined angular position of the crankshaft 6 .
  • the accelerator opening sensor 29 is a sensor that actually measures the depression amount of the accelerator pedal 33 and outputs the measured value as an accelerator opening signal ACC.
  • the cam angle sensor 30 is a sensor that outputs a cam angle signal CAM for each predetermined angular position of the intake camshaft 10 .
  • the water temperature sensor 31 is a sensor that actually measures the temperature of the cooling water of the internal combustion engine 1 (for example, the cooling water flowing through the water jacket 10c) and outputs the measured value as a water temperature signal TW.
  • the air-fuel ratio sensor 32 is installed in the exhaust pipe 17 upstream of the catalytic converter 18, and is a sensor that actually measures the air-fuel ratio of the exhaust gas and outputs the measured value as an air-fuel ratio signal AF.
  • the ECM 24 receives, in addition to signals from the various sensors described above, signals from an ignition switch (in other words, an engine switch) 34, which is a main switch for operating and stopping the internal combustion engine 1.
  • the VTC controller 25 realizes the function of controlling the variable valve timing mechanism 22 by having its microcomputer receive the target value TA from the ECM 24 while the processor reads the program stored in the non-volatile memory into the volatile memory and executes it. is doing. Specifically, the VTC controller 25 performs phase feedback control to generate and output a drive signal for the motor 23 so that the rotational phase approaches the target value TA.
  • the VTC controller 25 inputs the crank angle signal CRANK and the cam angle signal CAM duplicated by the ECM 24 via dedicated signal lines in order to detect the current rotational phase in the phase feedback control described above.
  • the VTC controller 25 can directly input the crank angle signal CRANK from the crank angle sensor 28 and directly input the cam angle signal CAM from the cam angle sensor 30 .
  • FIG. 2 shows an example of signal patterns of the crank angle signal CRANK and the cam angle signal CAM.
  • the crank angle sensor 28 detects, for example, a projection provided around the crankshaft 6 or a rotating body that rotates therewith, and outputs a pulse-like crank signal CRANK that changes in level in accordance with the detection of this projection.
  • the cam angle sensor 30 detects, for example, a projection provided around the intake camshaft 10 or a rotating body rotating therewith, and a pulsed cam angle signal CAM whose level changes in accordance with the detection of the projection. to output
  • the crank angle signal CRANK is one pulse for each crank angle (180 deg. CA for a 4-cylinder engine) corresponding to the stroke phase difference (ignition interval) between cylinders among the pulses rising for each unit crank angle (for example, 10 deg. CA). Alternatively, it becomes a signal pattern in which a plurality of continuous pulses are missing.
  • a pulse missing point in the crank angle signal CRANK occurs at the same timing as when the piston 4 is positioned at the reference piston position, and is set corresponding to each of the pistons of the plurality of cylinders.
  • the angular position of the crankshaft 6 when the ECU 24 detects a missing portion of the pulse in the crank angle signal CRANK will be referred to as a reference crank angle position.
  • the crank angle sensor 28 outputs a unit crank angle signal, which is a pulse that rises for each unit crank angle, and a reference crank angle signal, which is a pulse that rises for each crank angle corresponding to the stroke phase difference between cylinders.
  • a unit crank angle signal which is a pulse that rises for each unit crank angle
  • a reference crank angle signal which is a pulse that rises for each crank angle corresponding to the stroke phase difference between cylinders.
  • the output timing of the reference crank angle signal is generated at the same timing as when the piston 4 is positioned at the reference piston position, and is set corresponding to each of the pistons of the plurality of cylinders.
  • the cam angle signal CAM has a signal pattern in which one pulse or a plurality of continuous pulses rise at each crank angle (180 deg. CA for a 4-cylinder engine) corresponding to the stroke phase difference (ignition interval) between cylinders. Since the intake camshaft 10 rotates at half the rotation speed of the crankshaft 6, the crank angle corresponding to the stroke phase difference between the cylinders is 180 degrees. In the case of CA, the cam angle corresponding to the stroke phase difference between the cylinders is 90 degrees. That is, the cam angle signal CAM has one or a plurality of consecutive pulses each time the intake camshaft 10 rotates 90 degrees.
  • the signal pattern of the cam angle signal CAM is a signal pattern that enables discrimination of cylinders (cylinder discrimination) in which the piston is positioned at the reference piston position.
  • the cam angle signal CAM is The crank angle is 180deg.
  • the number of pulses that repeatedly rise for each CA changes in the order of 1 ⁇ 3 ⁇ 4 ⁇ 2.
  • the cam angle signal CAM for discriminating cylinders is not limited to the signal pattern described above, and it is sufficient if the cylinder number and the number of pulses are associated in advance.
  • the ECM 24 has a crank angle of 180deg.
  • the number of pulses of the cam angle signal CAM is counted for each CA, and cylinder discrimination is performed based on the number of pulses.
  • the ECM 24 may discriminate cylinders based on the change in the number of pulses in addition to the number of pulses of the cam angle signal CAM itself.
  • the cam angle signal CAM indicates that the crank angle is 180 deg.
  • a signal pattern in which the number of rising pulses for each CA changes, for example, in the order of 1 ⁇ 2 ⁇ 2 ⁇ 1 may be used.
  • the ECM 24 may discriminate cylinders based on the pulse width and amplitude of the cam angle signal CAM.
  • variable valve timing mechanism 22 shows an example of the structure of the variable valve timing mechanism 22.
  • FIG. the structure of the variable valve timing mechanism 22 is not limited to those exemplified in FIGS.
  • the intake camshaft 10 is rotatably supported by the cylinder head 3 via bearings 35 .
  • the variable valve timing mechanism 22 shown in FIGS. 3 to 5 includes a timing sprocket 36, which is a drive rotor that is rotationally driven by the crankshaft 6 of the internal combustion engine 1 and transmits rotational force to the intake camshaft 10, and a timing sprocket 36. 36 and is fixed to the chain cover 37 by bolts 38; and a phase changing device 40 for changing the
  • the timing sprocket 36 is composed of a sprocket body 36a and a gear portion 36b which is integrally provided on the outer periphery of the sprocket body 36a and receives the rotational force from the crankshaft 6 via a wound timing chain 41. .
  • the timing sprocket 36 is rotatably supported on the intake camshaft 10 by a first ball bearing 42 as a bearing.
  • the first ball bearing 42 is interposed between a circular groove 36c formed in the inner circumference of the sprocket body 36a and the outer circumference of the flange portion 10a integrally provided at the front end portion of the intake camshaft 10. As shown in FIG.
  • annular projection 36d is integrally formed on the outer peripheral edge of the front end portion of the sprocket main body 36a.
  • annular member 43 coaxially positioned on the inner periphery of the annular protrusion 36d and having internal teeth 43a, which are corrugated meshing portions formed on the inner periphery thereof, and an annular plate 44; They are fixed together by bolts 45 from the axial direction.
  • a stopper convex portion 36e which is an arc-shaped engaging portion, is formed over a predetermined range along the circumferential direction on a portion of the inner peripheral surface of the sprocket main body 36a.
  • a cylindrical housing 47 that covers the speed reducer 46 and the motor 23 constituting the phase changing device 40 is fixed to the outer periphery of the front end of the plate 44 with bolts 48 .
  • the housing 47 is made of a ferrous metal, functions as a yoke of the motor 23, and integrally has an annular plate-shaped housing holding portion 47a at its front end. are arranged so as to be covered with a predetermined gap.
  • the flange portion 10a of the intake camshaft 10 is formed with a stopper concave groove 10b along the circumferential direction, which is a locking portion into which the stopper convex portion 36e of the sprocket body 36a is engaged.
  • This stopper recessed groove 10b is formed in a circular arc shape with a predetermined length along the circumferential direction, and both end edges of the stopper convex portion 36e rotated within this length range are aligned with opposing edges 10c and 10d in the circumferential direction, respectively.
  • the contact mechanically regulates the relative rotational position of the intake camshaft 10 with respect to the timing sprocket 36 in the advancing direction and the retarding direction.
  • the stopper protrusion 36e and the stopper groove 10b constitute a mechanical stopper
  • the angular range in which the stopper protrusion 36e can move within the stopper groove 10b is the operating range of the variable valve timing mechanism 22, in other words, the rotational range. It becomes the variable range of the phase.
  • the position where the end edge of the stopper projection 36e abuts one of the opposed edges 10c and 10d of the stopper groove 10b is the most advanced position of the valve timing limited by the mechanical stopper, and the position where the other edge abuts is , the most retarded position of the valve timing limited by the mechanical stopper.
  • a driven member 49 which is a driven rotating body is axially coupled to the front end of the intake camshaft 10 by a cam bolt 50 .
  • a flange-shaped bearing surface portion 50b is integrally formed at the edge of the head portion 50a of the cam bolt 50.
  • a male threaded portion is formed on the outer periphery of the shaft portion 50c to be screwed into a female threaded portion formed axially inward from the end portion of the intake camshaft 10 .
  • the driven member 49 is made of an iron-based metal material and, as shown in FIG. 4, comprises a disk portion 49a formed at the front end and a cylindrical portion 49b integrally formed at the rear end. be.
  • the disc portion 49a of the driven member 49 is integrally provided with an annular step projection 49c having substantially the same outer diameter as the flange portion 10a of the intake camshaft 10 at substantially the center position in the radial direction of the rear end surface.
  • the outer peripheral surface of the annular step projection 49c and the outer peripheral surface of the flange portion 10a are arranged to pass through the inner periphery of the inner ring 42a of the first ball bearing 42.
  • the outer ring 42b of the first ball bearing 42 is press-fitted and fixed to the inner peripheral surface of the circular groove 36c of the sprocket body 36a.
  • a holder 52 for holding a plurality of rollers 51 is integrally provided on the outer peripheral portion of the disk portion 49a of the driven member 49. As shown in FIG.
  • the retainer 52 protrudes from the outer peripheral portion of the disk portion 49a in the same direction as the cylindrical portion 49b, and has a plurality of elongated protrusions 52a formed at substantially equal intervals in the circumferential direction with predetermined gaps.
  • the cylindrical portion 49b has an insertion hole 49d through which the shaft portion 50c of the cam bolt 50 is inserted, and a needle bearing 53 is provided on the outer circumference of the cylindrical portion 49b.
  • the cover member 39 is made of a synthetic resin material and is composed of a cup-shaped bulging cover body 39a and a bracket 39b integrally provided on the outer circumference of the rear end portion of the cover body 39a.
  • the cover main body 39a is arranged so as to cover substantially the entire front end of the phase changing device 40, that is, from the axial holding portion 47b of the housing 47 to the rear end with a predetermined gap.
  • the bracket 39b is formed in a substantially annular shape, and bolt insertion holes 39c are formed through each of the six boss portions.
  • the bracket 39b is fixed to the chain cover 37 via the bolts 38, and on the inner peripheral surface of the front end portion 39d of the cover body 39a, double inner and outer slip rings 54a and 54b are provided with their inner end surfaces exposed. Buried and fixed.
  • a connector portion 55 having connector terminals 55a connected to the slip rings 54a and 54b via conductive members is provided at the upper end portion of the cover member 39. As shown in FIG. Power is supplied from a battery power source (not shown) to the connector terminal 55a via the VTC controller 25. FIG.
  • a first oil seal 56 as a sealing member is interposed between the inner peripheral surface of the rear end portion of the cover body 39 a and the outer peripheral surface of the housing 47 .
  • the first oil seal 56 has a substantially U-shaped cross section, and a metal core is embedded inside a base material of synthetic rubber.
  • An annular base portion 56a on the outer periphery of the first oil seal 56 is fitted and fixed in a circular groove 39e formed in the inner peripheral surface of the rear end portion of the cover body 39a.
  • a seal surface 56b that contacts the outer peripheral surface of the housing 47 is integrally formed on the inner periphery of the annular base portion 56a of the first oil seal 56 .
  • the phase changing device 40 is composed of a motor 23 arranged substantially coaxially at the front end of the intake camshaft 10 and a speed reducer 46 that reduces the rotation speed of the motor 23 and transmits it to the intake camshaft 10 .
  • the motor 23 is a brushed DC motor (DC brush motor), and includes a housing 47 that is a yoke that rotates together with the timing sprocket 36, and a motor shaft that is an output shaft that is rotatably provided inside the housing 47. 57, a pair of semicircular permanent magnets 58 and 59 fixed to the inner peripheral surface of the housing 47, and a stator 60 fixed to the inner bottom surface of the housing holding portion 47a.
  • the motor shaft 57 is formed in a cylindrical shape and functions as an armature.
  • An iron core rotor 61 having a plurality of poles is fixed to the outer periphery at a substantially central position in the axial direction.
  • An electromagnetic coil 62 is wound around the outer periphery of the iron core rotor 61. It is A commutator 63 is press-fitted and fixed to the outer circumference of the front end of the motor shaft 57. Electromagnetic coils 62 are connected to the commutator 63, which is divided into segments having the same number of poles as the iron core rotor 61.
  • the motor shaft 57 is rotatably supported on the outer peripheral surface of the shaft portion 50c via a needle bearing 53 and a second ball bearing 64 which is a bearing disposed on the axial side of the needle bearing 53. ing.
  • a cylindrical eccentric shaft portion 65 forming part of the speed reducer 46 is integrally provided at the rear end portion of the motor shaft 57 .
  • a second oil seal 66 is provided between the outer peripheral surface of the motor shaft 57 and the inner peripheral surface of the plate 44 to prevent leakage of lubricating oil from inside the speed reducer 46 into the motor 23 .
  • the second oil seal 66 applies frictional resistance to the rotation of the motor shaft 57 by elastically contacting the outer peripheral surface of the motor shaft 57 with the inner peripheral portion thereof.
  • the speed reducer 46 includes an eccentric shaft portion 65 that performs eccentric rotational motion, a third ball bearing 67 that is a bearing provided on the outer circumference of the eccentric shaft portion 65, and a roller 51 that is provided on the outer circumference of the third ball bearing 67. , a retainer 52 that retains the roller 51 in the rolling direction and allows radial movement, and a driven member 49 integrated with the retainer 52 .
  • the axis of the cam surface formed on the outer peripheral surface of the eccentric shaft portion 65 is slightly eccentric from the axis X of the motor shaft 57 in the radial direction.
  • the third ball bearing 67, the roller 51, etc. are configured as a planetary meshing portion.
  • the third ball bearing 67 is arranged in a state in which the entire part substantially overlaps with the needle bearing 53 in the radial direction.
  • the inner ring 67a of the third ball bearing 67 is press-fitted and fixed to the outer peripheral surface of the eccentric shaft portion 65, and the roller 51 is always in contact with the outer peripheral surface of the outer ring 67b of the third ball bearing 67.
  • An annular gap C is formed on the outer circumference of the outer ring 67b, and the gap C allows the entire third ball bearing 67 to move radially along with the eccentric rotation of the eccentric shaft portion 65, that is, to move eccentrically. ing.
  • Each roller 51 is fitted into the inner tooth 43a of the annular member 43 while moving in the radial direction with the eccentric motion of the third ball bearing 67, and is guided in the radial direction by the protrusion 52a of the retainer 52. oscillating motion.
  • Lubricating oil is supplied to the interior of the speed reducer 46 by a lubricating oil supply means.
  • the lubricating oil supply means includes an oil supply passage 35a formed inside the bearing 35 of the cylinder head and supplied with lubricating oil from a main oil gallery (not shown), and an oil supply passage 35a formed in the inner axial direction of the intake camshaft 10 to supply the oil.
  • An oil supply hole 68 communicates with the passage 35a through a groove, and an oil supply hole 68 is formed through the driven member 49 in the axial direction. It is composed of a small-diameter oil supply hole 69 opened in the vicinity thereof and three large-diameter oil discharge holes (not shown) also formed through the driven member 49 .
  • variable valve timing mechanism 22 The operation of the variable valve timing mechanism 22 will be described below.
  • the timing sprocket 36 rotates via the timing chain 41 , and the rotational force causes the motor 23 to rotate synchronously via the housing 47 , the annular member 43 and the plate 44 .
  • the rotational force of the annular member 43 is transmitted from the roller 51 to the intake camshaft 10 via the retainer 52 and the driven member 49, and the intake camshaft 10 rotates.
  • the intake cams 11 provided on the intake camshaft 10 open and close the intake valves 8 .
  • the VTC controller 25 When advancing or retarding the rotational phase, that is, the valve timing of the intake valve 8, the VTC controller 25 energizes the motor 23 of the variable valve timing mechanism 22 to generate torque.
  • the output torque of motor 23 is transmitted to intake camshaft 10 via reduction gear 46 .
  • each roller 51 is radially guided by the protrusion 52a of the retainer 52 for each rotation of the motor shaft 57, and moves toward one of the annular members 43. It rolls over the internal tooth 43a and moves to another adjacent internal tooth 43a, and rolls in the circumferential direction while repeating this in sequence.
  • Rotation of the motor shaft 57 is decelerated by the rolling contact of the rollers 51 , and torque is transmitted to the driven member 49 .
  • the speed reduction ratio when the rotation of the motor shaft 57 is transmitted to the driven member 49 can be arbitrarily set depending on the number of rollers 51 and the like.
  • the intake camshaft 10 rotates in the forward and reverse directions relative to the timing sprocket 36 to change the rotation phase, and the opening/closing timing (valve timing) of the intake valve 8 changes in the advancing direction or the retarding direction.
  • the motor 23 receives rotational driving force from the timing sprocket 36 and is driven to rotate, and the motor shaft 57 rotates at the same rotational speed as the timing sprocket 36, the rotation phase does not change.
  • variable valve timing mechanism 22 advances the valve timing by generating a difference between the two amounts of rotation of the motor shaft 57 and the timing sprocket 36, in other words, the relative rotation speed of the motor shaft 57 with respect to the timing sprocket 36. It can be angular or retarded.
  • FIG. 6 shows a schematic configuration of the ECM 24 and VTC controller 25 regarding control of the variable valve timing mechanism 22. As shown in FIG.
  • the ECM 24 has the functions of a target value calculator 241 and a replication processor 242 .
  • the target value calculation unit 241 calculates a target value TA of the rotation phase (in other words, the valve timing of the intake valve 8) based on the operating state of the internal combustion engine 1, and transmits information of the calculated target value TA to the VTC controller 25. do.
  • a duplication processor 242 duplicates the crank angle signal CRANK from the crank angle sensor 28, duplicates the cam angle signal CAM from the cam angle sensor 30, and converts the duplicated signals of the crank angle signal CRANK and the cam angle signal CAM to VTC. Send to controller 25 .
  • the VTC controller 25 has the functions of a phase detection value acquisition section 251 , a phase change amount calculation section 252 , a phase estimation section 253 and a drive control section 254 , and a motor drive circuit 255 .
  • the phase detection value acquisition unit 251 periodically acquires the phase detection value MA as the rotational phase based on the duplicate signals of the crank angle signal CRANK and the cam angle signal CAM transmitted by the ECM 24 . Specifically, as shown in FIG. 2, the phase detection value acquiring unit 251 calculates the crank angle from the reference crank angle position detected based on the crank angle signal CRANK to the next rise of the cam angle signal CAM as a unit crank angle. It is measured based on the number of pulses that rise at each angle. Then, the phase detection value acquisition unit 251 converts the measured crank angle into a phase detection value MA [deg. CA].
  • the phase change amount calculation unit 252 calculates the rotation phase change amount ⁇ A per unit period (for example, one control cycle) ⁇ t based on the later-described operation voltage V mot calculated by the drive control unit 254 .
  • the details of the phase change amount calculator 252 will be described later.
  • the phase estimator 253 calculates an estimated value (phase estimated value) EA of the rotational phase during which the phase detected value MA is periodically obtained based on the phase detected value MA and the amount of change ⁇ A. Details of the phase estimation unit 253 will be described later.
  • the drive control unit 254 applies PI control or the like to the difference between the phase estimation value EA and the rotational phase target value TA obtained from the transmission signal of the ECM 24 to calculate the operating voltage V mot [volt] of the motor 23 .
  • the operation voltage V mot is calculated as a positive value, it is an operation amount for rotating the motor 23 in the forward direction, and when it is calculated as a negative value, it is an operation amount for rotating the motor 23 in the reverse direction. be the manipulated variable.
  • the drive control unit 254 compares the level of the calculated operating voltage V mot with a triangular wave or sawtooth wave carrier signal to generate a pulse PWM (Pulse Width Modulation) signal having two different potential levels. .
  • the PWM signal is output as a drive signal for the motor 23 to the motor drive circuit 255 via a pre-driver or the like if necessary.
  • the motor drive circuit 255 has a switching element such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), for example.
  • the switching element of the motor drive circuit 255 performs a switching operation based on the PWM signal output from the drive control unit 254, so that the motor drive current corresponding to the operating voltage Vmot is supplied to the motor 23.
  • FIG. 1 Metal-Oxide-Semiconductor Field-Effect Transistor
  • FIG. 7 is a block diagram showing the main functions of the VTC controller 25, that is, the details of the phase change amount calculator 252 and the phase estimator 253.
  • the phase change amount calculator 252 is subdivided into functions of a motor drive current estimator 2521 , a motor torque estimator 2522 , a motor angular velocity estimator 2523 , an integrator 2524 and a unit converter 2525 .
  • the phase estimation unit 253 is subdivided into functions of an integration processing unit 2531 , a reset unit 2532 and an interpolation unit 2533 .
  • the motor drive current estimator 2521 estimates the motor drive current I[A] based on the operating voltage V mot previously calculated by the drive controller 254 . Specifically, the motor drive current estimator 2521 substitutes the value of the operating voltage V mot into the following equation (1), which is the circuit equation for the electric circuit model of the motor 23, and also substitutes the resistance value R of the motor coil and Predetermined calculation constant values such as the inductance L and the induced voltage constant Kv are substituted.
  • the motor drive current estimation unit 2521 simply converts the operation voltage V mot calculated by the drive control unit 254 into the known internal resistance value R in of the motor 23 instead of using the circuit equation for the electric circuit model described above.
  • the motor drive current I may be calculated by division.
  • the motor torque estimator 2522 calculates the value of the motor drive current I estimated by the motor drive current estimator 2521 based on a known relational expression between the motor drive current I and the motor torque T mot [N ⁇ m] in the motor 23. Estimate the corresponding motor torque T mot . Specifically, the motor torque estimator 2522 adds a value of the motor drive current I estimated by the motor drive current estimator 2521 to a torque constant Kt that defines the proportional relationship between the motor drive current I and the motor torque Tmot . A value of the motor torque T mot is derived by multiplying by a predetermined calculation constant.
  • Motor angular velocity estimator 2523 estimates motor angular velocity ⁇ [rad/s] corresponding to the value of motor torque T mot estimated by motor torque estimator 2522 . Specifically, the motor angular velocity estimator 2523 substitutes the value of the motor torque T mot into the following equation (2), which is the equation of motion for the physical model of the variable valve timing mechanism 22, and also the moment of inertia J and the coefficient of friction A value of a predetermined calculation constant such as D and a value of cam torque T cam are substituted.
  • the moment of inertia J is the moment of inertia of rotating elements such as the rotor 61 of the motor 23 .
  • the coefficient of friction D is a coefficient of dynamic friction for sliding due to relative rotation between the intake camshaft 10 and the motor 23 .
  • the value of the cam torque T cam can be obtained based on the engine load information of the internal combustion engine 1 received from the ECM 24 .
  • the value of d ⁇ /dt that is, the motor angular velocity ⁇ is derived from the following equation (2) in which the motor torque T mot , the cam torque T cam , the moment of inertia J, and the coefficient of friction D are substituted.
  • the integrator 2524 integrates the value of the motor angular velocity ⁇ estimated by the motor angular velocity estimator 2523 to calculate the motor angle change amount ⁇ [rad] per unit period ⁇ t.
  • a unit conversion unit 2525 converts the motor angle change amount ⁇ [rad] calculated by the integrator 2524 based on the speed reduction ratio of the speed reducer 46 and the rotation speed ratio between the intake camshaft 10 and the crankshaft 6 into a crank angle.
  • the rotation phase change amount ⁇ A [deg. CA].
  • the integration processing unit 2531 calculates the rotation phase change amount ⁇ A [deg. CA], and holds the integrated value ⁇ A obtained by the integration until the reset unit 2532 resets it.
  • the reset unit 2532 resets the detected phase value MA [deg. CA] is acquired, the integrated value ⁇ A integrated by the integration processing unit 2531 is reset to zero.
  • the interpolation unit 2533 calculates the integrated value ⁇ A of the change amount ⁇ A integrated by the integration processing unit 2531 from the phase detection value MA [deg. CA], and the addition result is the phase estimate value EA [deg. CA].
  • FIG. 8 schematically shows the relationship between the phase detection value MA and the phase estimation value EA during phase feedback control when the target value TA changes from the previous target value TA1 to the current target value TA2.
  • the phase estimator 253 calculates the phase estimation value EA based on the newly acquired phase detection value MA1.
  • the phase change amount calculator 252 calculates the change amount ⁇ A of the rotational phase every unit period ⁇ t from time t1. Further, the phase estimator 253 calculates an integrated value ⁇ A by integrating the change amount ⁇ A for each unit period ⁇ t, and calculates a value (MA1+ ⁇ A) obtained by adding the integrated value ⁇ A and the phase detection value MA1 as the phase estimation value EA. do.
  • phase estimator 253 When the phase detection value MA2 is newly acquired at time t2, the phase estimator 253 forcibly corrects the latest calculated value of the phase estimation value EA to the newly acquired phase detection value MA2. Specifically, phase estimating section 253 resets integrated value ⁇ A at that time to zero, and adds a value obtained by adding the reset integrated value ⁇ A and the newly acquired phase detection value MA2 as phase estimated value EA. do. In this way, the phase detection value MA is interpolated with the phase estimation value EA between the timings of obtaining the phase detection value MA. Note that the unit time ⁇ t1 is shorter than the time from time t1 to time t2, so the phase estimation value EA is calculated one or more times while the phase detection value MA is being obtained.
  • the resistance value R the induced voltage constant K v , the inductance L, the internal resistance value R in , the torque constant K t , the friction coefficient D, the inertia Computational constants such as moment J are used.
  • These calculation constants can originally take different values depending on variations (individual differences) in the electrical and mechanical characteristics of the variable valve timing mechanism 22 and changes in the ambient environment such as temperature.
  • the estimated value EA is calculated with the calculation constant as a fixed value. When the phase feedback control is performed using the phase estimated value EA calculated by such calculation, as shown in FIG. It may not be uniform between different individuals or between different surroundings. As shown in FIG.
  • the actual value RA and the estimated phase value EA deviate depending on the amount of change ⁇ A and, in turn, the value of the calculation constant used to calculate the estimated phase value EA. It is assumed that the change to the value TA2 is slower than the actual value RA. In this case, the actual value RA reaches the current target value TA2 earlier than the phase estimation value EA, but since the phase estimation value EA has not reached the current target value TA2, the rotational driving of the motor 23 is continued. be. Therefore, there is a possibility that the actual value RA will exceed the current target value TA2 and the excess amount OS will overshoot (hatched portion in the figure).
  • the stopper projection 36e colliding with either of the opposing edges 10c and 10d of the stopper groove 10b increases.
  • the stopper projection 36e is positioned close to either of the opposed edges 10c and 10d of the stopper groove 10b. significantly increased sexuality. If collisions are repeated, the durability of the mechanical stopper formed by the stopper protrusion 36e and the stopper groove 10b may deteriorate, or the variable valve timing mechanism 22 may become stuck.
  • slowly changing means that the absolute value of the change speed of the phase estimation value EA approaching the current target value TA2 is the current target value regardless of the magnitude relationship between the target values TA1 and TA2. Less than the absolute value of the rate of change of the actual value RA approaching the value TA2. Conversely, “changes rapidly” means that the absolute value of the rate of change of the phase estimation value EA that approaches the current target value TA2, regardless of the magnitude relationship between the target values TA1 and TA2, is the actual value RA that approaches the current target value TA2. is greater than the absolute value of the rate of change of
  • FIG. 9 schematically shows the relationship between the actual value RA and the phase estimated value EA during phase feedback control when the target value TA changes from the previous target value TA1 to the current target value TA2.
  • the value of the calculation constant used to calculate the amount of change ⁇ A is such that the phase estimated value EA changes toward the current target value TA2 faster than the actual value RA (higher response). is preset and stored in non-volatile memory.
  • the phase change amount calculator 252 calculates a change amount ⁇ A using a calculation constant value (hereinafter referred to as a “high-response possible value”) that enables high responsiveness of the phase estimation value EA, and calculates the change amount ⁇ A , the phase estimator 253 calculates the phase estimation value EA.
  • a first calculation mode Calculation of the phase estimation value EA using the high-response possible value in the VTC controller 25 in this manner is referred to as a first calculation mode.
  • the high responsiveness possible value is set in advance from the range of values (hereinafter referred to as "constant fluctuation range") that each calculation constant can take due to individual differences assumed for the variable valve timing mechanism 22 and changes in the surrounding environment.
  • the phase estimation value EA is calculated using the values of each calculation constant selected from the constant fluctuation range, and the phase estimation value EA is shifted toward the current target value TA2 by the actual value RA See if it changes faster than
  • the high-response possible value is one of the combinations of calculation constants used to calculate the phase estimate EA when the phase estimate EA changes toward the current target value TA2 faster than the actual value RA. is appropriately set from
  • the values of the calculation constants of the resistance value R, the induced voltage constant K v , the coefficient of friction D, the moment of inertia J, and the inductance L are set to the minimum values of the respective constant fluctuation ranges, and the torque
  • the value of constant Kt can be set to the maximum value of the constant variation range.
  • the amount of change ⁇ A calculated using the calculation constants of the high-response possible values set in this manner simultaneously becomes the maximum value larger than the amount of change ⁇ A calculated with other values in the constant fluctuation range of each calculation constant. .
  • the phase change amount calculator 252 can reset (or correct) the high-response possible value based on the difference ⁇ X each time the phase detection value MA1 is obtained.
  • the phase variation calculation unit 252 determines that the phase estimation value EA is less than the actual value RA. I think it's changing slowly. Then, the phase change amount calculator 252 resets the high-response possible value within the constant fluctuation range of each calculation constant so as to increase the change amount ⁇ A according to the value of the difference ⁇ X. However, if the value of the calculation constant that makes the amount of change ⁇ A the maximum value has already been set as a high-response possible value, the high-response possible value that further increases the amount of change ⁇ A is not set again.
  • the phase estimation value EA moves toward the current target value TA2 toward the actual value RA
  • a first calculation mode is performed in which calculations are performed so as to change faster than . Therefore, as shown in FIG. 9, the estimated phase value EA reaches the current target value TA2 earlier than the actual value RA, and the rotational drive of the motor 23 is stopped or the rotational drive amount is extremely reduced. .
  • phase change amount calculator 252 of the VTC controller 25 is changed to a phase change amount calculator 252A
  • FIG. 10 to 12 the same code
  • FIG. 10 shows details of the phase change amount calculator 252A.
  • the phase change amount calculator 252A includes a first comparator 2526 and a second comparator 2527. , deceleration detection unit 2528 and selection unit 2529 .
  • the first comparison unit 2526 determines whether or not the operating voltage V mot calculated last time by the drive control unit 254 is equal to or greater than 0 [volt], and generates first comparison information D1, which is the determination result.
  • the VTC controller 25 drives the motor 23 to rotate in the forward direction
  • the VTC controller 25 rotates the motor 23 . shall be driven to rotate in the reverse direction.
  • the second comparison unit 2527 determines whether or not the motor angular velocity ⁇ calculated last time by the motor angular velocity estimation unit 2523 is equal to or greater than zero [rad/s], and generates second comparison information D2 as the determination result. .
  • the motor 23 is rotating in the forward direction when the motor angular velocity ⁇ is a positive value, and that the motor 23 is rotating in the reverse direction when the motor angular velocity ⁇ is a negative value. do.
  • the deceleration detection unit 2528 determines that the change speed of the actual value RA toward the current target value TA2 is decreasing (that is, the actual value RA is decelerating) based on the first comparison information D1 and the second comparison information D2. ), and generates deceleration information Ds as a result of the detection. Detecting whether or not the actual value RA is decelerating is, in other words, detecting whether or not the motor 23 is being braked to converge the phase estimate EA to the current target value TA2.
  • the braking operation of the motor 23 is to rotationally drive (energize) the motor 23 so that the rotation speed of the motor 23 becomes slow.
  • the braking operation of the motor 23 is not limited, but the value of the operating voltage V mot changes from positive to negative or from negative to positive to rotate the motor 23 in the direction opposite to the current rotation direction. shall be driven to
  • the deceleration detection unit 2528 determines that one of the operation voltage V mot and the motor angular velocity ⁇ is less than zero and the other is greater than or equal to zero based on the first and second comparison information D1 and D2. If so, it detects that the actual value RA is decelerating. Then, the deceleration detection unit 2528 sets the deceleration information Ds to 1, for example, and generates it. When either the operating voltage V mot or the motor angular velocity ⁇ is zero, it is difficult to say that the motor 23 is being braked. treated as if they existed.
  • both the operating voltage V mot and the motor angular velocity ⁇ are equal to or greater than zero or less than zero, the motor 23 is driven to rotate in the same direction as the current rotation direction, so the motor 23 is braked. is not performed. Therefore, when the deceleration detection unit 2528 determines that both the operation voltage V mot and the motor angular velocity ⁇ are greater than or equal to zero or less than zero based on the first and second comparison information D1 and D2, the actual value Detects that the RA is not decelerating (non-decelerating). Then, the deceleration detection unit 2528 sets the deceleration information Ds to 0, for example, and generates the deceleration information Ds.
  • the selection unit 2529 selects a high-response possible value or a low-response value as the value of the calculation constant used in the calculations performed by the motor drive current estimator 2521, the motor torque estimator 2522, and the motor angular velocity estimator 2523. Choose one of the possible values.
  • the high-response possible value is the value of the calculation constant that enables high-response phase estimation value EA, as described above.
  • the response-lowering possible value is a value of a calculation constant that enables a low-response phase estimation value EA. means that it changes slowly.
  • the possible low response value is set in advance from the above constant variation range for each calculation constant.
  • the phase estimated value EA is calculated using the values of each calculation constant selected from the constant fluctuation range, and the phase estimated value EA calculated by such calculation is the current target value.
  • the response-lowering possible value is one of the combinations of calculation constant values used to calculate the phase estimate value EA when the phase estimate value EA changes toward the current target value TA2 slower than the actual value RA. is appropriately set from
  • the value of each calculation constant of the resistance value R, the induced voltage constant K v , the friction coefficient D, the moment of inertia J, and the inductance L is set to the maximum value of each constant variation range, and the torque
  • the value of constant Kt can be set to the minimum value of the constant variation range.
  • the amount of change ⁇ A calculated using the calculation constants of the low response possible values set in this manner simultaneously becomes the minimum value that is smaller than the amount of change ⁇ A calculated with other values in the constant fluctuation range of each calculation constant. .
  • the selection unit 2529 selects a low response possible value.
  • the selection unit 2529 selects a high-response possible value.
  • the motor drive current estimator 2521, the motor torque estimator 2522, and the motor angular velocity estimator 2523 use either the high-response possible value or the low-response possible value selected by the selection unit 2529 as the calculation constant of each calculation.
  • the phase change amount calculation unit 252A calculates the change amount ⁇ A using either the high response possible value or the low response possible value, and based on the change amount ⁇ A calculated by such calculation, , the phase estimator 253 calculates the phase estimation value EA.
  • computing the phase estimation value EA using the high-response possible value is referred to as the first computation mode. is referred to as a second calculation mode.
  • FIG. 11 shows the effect of braking operation of the motor 23 by phase feedback control when the target value TA changes from the previous target value TA1 to the current target value TA2 in the VTC controller 25 having the phase change amount calculator 252. .
  • (a) of FIG. 11 shows the change over time of the target value TA, the estimated phase value EA, and the actual value RA, and (b) of FIG . Indicates time change.
  • the VTC controller 25 having the phase change amount calculator 252A calculates the phase estimate value EA in the first calculation mode.
  • the phase estimate EA changes toward the current target value TA2 faster than the actual value RA. Therefore, the phase estimated value EA approaches the current target value TA2 earlier than the actual value RA, and in order to converge the phase estimated value EA to the current target value TA2, the operating voltage V mot is set to a negative value and the motor 23 is performed (see the hatched portion in FIG. 11(b)).
  • the braking operation is temporarily terminated, so the braking operation ends before the actual value RA converges.
  • FIG. 12 shows the effect of braking operation of the motor 23 by phase feedback control when the target value TA changes from the previous target value TA1 to the current target value TA2 in the VTC controller 25 having the phase change amount calculation section 252A.
  • (a) of FIG. 12 shows the change over time of the target value TA, the estimated phase value EA, and the actual value RA, and (b) of FIG . Indicates time change.
  • the VTC controller 25 having the phase change amount calculation unit 252A changes the first A phase estimate value EA is calculated in the calculation mode.
  • the VTC controller 25 having the phase change amount calculation unit 252A sets the operation voltage V mot to a negative value and the braking operation of the motor 23 is started (see the hatched portion in FIG. 12(b))
  • the first calculation Switch the mode to the second computation mode.
  • calculation of the phase estimation value EA in the second calculation mode is started.
  • phase estimate EA When the phase estimate EA is calculated in the second calculation mode, the phase estimate EA changes toward the current target value TA2 slower than the actual value RA. Therefore, even if the brake operation is started, the convergence of the phase estimated value EA to the current target value TA2 is delayed compared to the case where the phase estimated value EA is continuously calculated in the first calculation mode, and the brake operation ends. Timing is also delayed. Assuming that the brake operation time at this time is ⁇ t B2 , the brake operation time ⁇ t B2 is longer than the brake operation time ⁇ t B1 .
  • the actual value RA exceeds the current target value TA2 by increasing the brake operation time when the phase estimate value EA converges to the current target value TA2. Possibility of overshoot can be reduced. As a result, it is possible to further suppress deterioration in the durability of the mechanical stopper constituted by the stopper protrusion 36e and the stopper groove 10b, and the fixation of the variable valve timing mechanism 22, and the like.
  • phase change amount calculator 252 of the VTC controller 25 is changed to a phase change amount calculator 252B.
  • FIG. 13 shows details of the phase change amount calculator 252B.
  • the phase change amount calculator 252B includes a first comparator 2526 and a second comparator 2527. , a deceleration detection unit 2528 , a selection unit 2529 , a third comparison unit 2530 and a logical product calculation unit 2531 .
  • the first comparison section 2526, the second comparison section 2527, the deceleration detection section 2528, and the selection section 2529 are the same as those included in the above-described phase change amount calculation section 252A, so the description thereof will be simplified.
  • the third comparison unit 2530 compares a parameter (hereinafter referred to as "target parameter") for which it is determined whether switching from the first calculation mode to the second calculation mode is necessary and a predetermined threshold value. Then, third comparing section 2530 generates third comparison information D3 indicating whether switching from the first calculation mode to the second calculation mode is necessary as a result of the comparison. At least one of the target value TA, the power supply voltage of the motor 23, and the engine speed of the internal combustion engine 1 can be used as the target parameter, although not limited thereto. The engine speed can be detected based on the crank angle signal CRANK or the cam angle signal CAM.
  • the target value TA is used as the target parameter.
  • the angular range in which the projection 36e can move within the stopper groove 10b is the variable range of the rotational phase.
  • the rotation phase when the stopper convex portion 36e is located closer to the opposing edge 10c than the opposing edge 10d but away from the opposing edge 10c is denoted by Tc.
  • the rotation phase when the stopper convex portion 36e is located closer to the opposing edge 10d than the opposing edge 10c but away from the opposing edge 10d is Td (>Tc).
  • the target value TA is set to Td, even if the phase estimation value EA is calculated in the first calculation mode continuously after the brake operation is started, the overshoot of the actual value RA causes the stopper projection 36e and the opposing edge to fall. Assume that the risk of colliding with 10d is negligible.
  • the third comparison unit 2530 switches from the first calculation mode to the second calculation mode on the condition that the target value TA satisfies the threshold value Tc or more and the threshold value Td or less (Tc ⁇ TA ⁇ Td).
  • Third comparison information D3 can be generated that indicates that there is no need for switching.
  • the third comparison unit 2530 does not need to switch from the first calculation mode to the second calculation mode on condition that the power supply voltage of the motor 23 is equal to or lower than the predetermined threshold value Vth . It is possible to generate the third comparison information D3 indicating that.
  • the third comparison unit 2530 determines whether it is necessary to switch from the first calculation mode to the second calculation mode on condition that the engine speed of the internal combustion engine 1 is equal to or higher than a predetermined threshold value Nth .
  • Third comparison information D3 can be generated to indicate that there is no
  • the third comparison information D3 is set to 1 when the comparison result between the target parameter and the predetermined threshold satisfies the predetermined condition, while the comparison result between the target parameter and the predetermined threshold satisfies the predetermined condition. If not, it is set to 0.
  • each parameter can be compared with a predetermined threshold value. Then, if one or more of these comparison results satisfy a predetermined condition, the third comparison section 2530 determines that there is no need to switch from the first operation mode to the second operation mode. can be generated.
  • the third comparison unit 2530 determines that the first calculation mode is changed to the second calculation mode when the risk of collision between the stopper projection 36e and the opposing edges 10c and 10d is minimal. Switching to calculation mode is prevented. Therefore, it is possible to suppress deterioration in the durability of the mechanical stopper, fixation of the variable valve timing mechanism 22, and the like. becomes possible.
  • the deceleration detection unit 2528 determines that one of the operating voltage V mot and the motor angular velocity ⁇ is less than zero and the other is greater than or equal to zero, it detects that the actual value RA is decelerating. However, the deceleration detection unit 2528 either uses the operating voltage V mot instead of the motor drive current I, uses the motor angular velocity ⁇ instead of the deviation between the target value TA and the phase estimation value EA, or performs both. may In short, in the phase feedback control using the motor 23, the deceleration detection unit 2528 can detect whether the actual value RA is decelerating based on the two control parameters of the manipulated variable and the controlled variable.
  • the operation amount the operation voltage Vmot , the motor driving current I, or the like can be used as described above.
  • the motor angular velocity ⁇ , the deviation between the target value TA and the phase estimation value EA, and the like can be used as the control amount.
  • the deceleration detection unit 2528 detects two values of the operation amount and the control amount. Based on the polarity of one control parameter, it can be detected whether the actual value RA is decelerating.
  • the manipulated variable and the controlled variable if positive indicates the forward rotation direction and negative indicates the reverse rotation direction, when the polarities of the two control parameters are opposite to each other, the actual It can be detected that the value RA is decelerating.
  • the deceleration detection unit 2528 detects whether or not the actual value RA has decelerated, not only based on the two control parameters of the operation amount and the control amount, but also the motor angular velocity ⁇ may be performed based on the time change of For example, the deceleration detection unit 2528 can detect that the actual value RA has decelerated when determining that the absolute value of the differential value of the motor angular velocity ⁇ has become equal to or less than a predetermined value.
  • the estimated value estimated by the motor drive current estimation unit 2521 is used as the motor drive current I.
  • the phase change amount calculators 252, 252A, and 252B may use, as the motor drive current I, a detected value detected by the current detecting means, or a calculated value calculated based on this detected value.
  • the current detection means is composed of, for example, a shunt resistor that converts the current flowing between the motor drive circuit 255 and the motor 23 into a voltage value, an amplifier circuit that amplifies the voltage value, and the like.
  • the second calculation is performed to improve the responsiveness of the variable valve timing mechanism 22 when the brake operation for converging the phase estimation value EA to the current target value TA2 is once finished. mode to the first computing mode.
  • the motor 23 is not limited to the DC brush motor described above, and may be a brushless motor. Also, instead of configuring the ECM 24 and the VTC controller 25 separately, a single electronic control device having the functions of the ECM 24 and the VTC controller 25 can be provided.
  • variable valve timing mechanism 22 is not limited to the device shown in FIGS. A variable valve timing device or the like can be adopted.
  • the variable valve timing mechanism 22 is a mechanism that changes the rotation phase, but instead or in addition to this, it may be a mechanism that changes the rotation phase of the exhaust camshaft 12 with respect to the crankshaft 6. can.
  • the ECM 24 and the VTC controller 25 can control the variable valve timing mechanism 22 with the same configuration and processing as described above, and can achieve the same effect.
  • the above functions of the ECM 24 and VTC controller 25 are realized by the processor reading the stored program from the non-volatile memory to the volatile memory and executing it in these microcomputers. You may do so. That is, some or all of the functions of the ECM 24 and VTC controller 25 may be realized by hardware configuration instead of software processing.
  • the phase change amount calculator 252 can reset the high-response possible value based on the difference ⁇ X each time the phase detection value MA1 is acquired.
  • the phase change amount calculation units 252A and 252B like the phase change amount calculation unit 252, each time the phase detection value MA1 is acquired, the response is increased based on the difference ⁇ X. Either of the possible value and the possible low-response value may be reset.
  • the phase change amount calculators 252A and 252B when calculating the phase estimation value EA in the first calculation mode, increase the change amount ⁇ A according to the negative value of the difference ⁇ X. In addition, the high-response possible value can be reset within the constant fluctuation range of each calculation constant. Further, when calculating the phase estimation value EA in the second calculation mode, the phase change amount calculators 252A and 252B reduce the change amount ⁇ A according to the positive value of the difference ⁇ X. In addition, the low response possible value can be reset within the constant fluctuation range of each calculation constant.
  • the value of the calculation constant that makes the amount of change ⁇ A the maximum value has already been set as a high-response possible value
  • the high-response possible value that further increases the amount of change ⁇ A is not set again.
  • the value of the calculation constant that makes the amount of change ⁇ A the minimum value has already been set as the low responsiveness possible value
  • the low responsiveness possible value that further decreases the amount of change ⁇ A is not set again.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

Selon la présente invention, pendant la commande d'un mécanisme de distribution variable de soupape capable d'utiliser la sortie de rotation d'un moteur pour modifier la phase de rotation d'un arbre à cames par rapport à un vilebrequin d'un moteur à combustion interne, une valeur de détection de la phase de rotation est périodiquement acquise sur la base d'un signal de sortie d'un capteur d'angle de vilebrequin qui détecte une position angulaire de l'arbre de vilebrequin et un signal de sortie d'un capteur d'angle de came qui détecte une position angulaire de l'arbre de came, une valeur d'estimation de la phase de rotation dans un intervalle de l'acquisition périodique de la valeur de détection est calculée en référence à une valeur de détection précédemment acquise, et une commande de rétroaction de phase est effectuée à l'aide du moteur de telle sorte que la valeur d'estimation calculée s'approche d'une valeur cible. Pendant la commande de rétroaction de phase, la valeur d'estimation est calculée de manière à changer plus rapidement qu'une valeur réelle de la phase de rotation vers la valeur cible.
PCT/JP2022/008314 2021-05-26 2022-02-28 Dispositif de commande pour mécanisme de distribution à programme variable et son procédé de commande WO2022249612A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000222005A (ja) * 1999-02-03 2000-08-11 Hitachi Ltd プロセスの制御装置
JP2019203673A (ja) * 2018-05-25 2019-11-28 株式会社ノーリツ 燃焼装置および給湯装置
JP2020079581A (ja) * 2018-11-14 2020-05-28 日立オートモティブシステムズ株式会社 可変バルブタイミング機構の制御装置及びその制御方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000222005A (ja) * 1999-02-03 2000-08-11 Hitachi Ltd プロセスの制御装置
JP2019203673A (ja) * 2018-05-25 2019-11-28 株式会社ノーリツ 燃焼装置および給湯装置
JP2020079581A (ja) * 2018-11-14 2020-05-28 日立オートモティブシステムズ株式会社 可変バルブタイミング機構の制御装置及びその制御方法

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