JP2010285932A - Cam phase variable type internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cam phase variable type internal combustion engine for, e.g., improving control responsiveness. <P>SOLUTION: In the cam phase variable type internal combustion engine, when the determination result in step S103 is No, an engine ECU 70 calculates a main control input value Umain(k) by an equation: Umain(k)=λUtemp(k-1)+Uoft(k) (where λ(0<λ<1) represents a forgetting coefficient, and Uoft(k) represents a fine value in an abutting direction of a VTC actuator 21). Hence, when a speed control end flag Fvcend or a holding mode flag Fcnstmd gets to 1 (i.e., when the speed control is ended), the main control input value Umain(k) gradually decreases from the time of speed control end. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cam phase variable internal combustion engine in which the cam phase is continuously variably controlled, and more particularly, to a technique for realizing improvement in control response.

  Many 4-cycle engines (hereinafter simply referred to as engines) are equipped with various variable valve mechanisms to improve output and fuel consumption, reduce harmful exhaust gas components, and the like. As a variable valve mechanism, instead of switching a plurality of existing cams (for example, a low speed type cam and a high speed type cam), the cam phase and In recent years, the valve lift and the individual individually continuously variable control have become mainstream. A valve timing control device (hereinafter referred to as VTC) used for variable control of the cam phase is a vane type hydraulic actuator (hereinafter referred to as VTC actuator) installed near the end of the camshaft in the cylinder head. And a linear solenoid for controlling the hydraulic pressure (engine hydraulic pressure) supplied to the VTC actuator (see Patent Documents 1 and 2).

  In general, in the VTC actuator, the cam phase is feedback controlled (phase control) according to the difference between the target cam phase and the actual cam phase, but the feedback gain at this time is misaligned for the sake of avoiding control overshoot and hunting. I can't make it bigger. Therefore, if the target cam phase and the actual cam phase deviate greatly due to the driver's sudden acceleration or deceleration operation, it takes a relatively long time until the target cam phase is established. There was a problem that brought about worsening. Therefore, in the control device disclosed in Patent Document 1, after suddenly changing the target relative rotation angle (target cam phase), the VTC actuator is driven at the maximum speed for a predetermined period and then switched to phase control to establish the target cam phase. Adopted. Further, in the control device of Patent Document 2, when the difference between the target cam phase and the actual cam phase is equal to or larger than a predetermined value, the VTC actuator is driven at the maximum speed until the difference becomes small, and then the control is switched to phase control. A method of establishing the cam phase is adopted.

Japanese Patent No. 4061674 JP 2007-332956 A

  However, since both methods of Patent Documents 1 and 2 ultimately control the phase of the VTC actuator, the required response speed of the cam phase change may not be satisfied. For example, in recent fuel-efficient engines, there are those that reduce the pumping loss at low rotation and partial load by the Atkinson cycle (for example, early closing or late closing of the intake valve: mirror cycle) and internal EGR. In some types of engines, the adjustment cost by the throttle valve is small, so it is necessary to instantaneously change the cam phase of the intake valve when the load changes suddenly. However, in the above-described method, although the actual cam phase of the VTC actuator approaches the target cam phase by driving at the maximum speed, it takes a certain time until the target cam phase is established by the phase control. Inevitable. In this case, the rate of change of the intake air amount is limited to a low value, and drivability deteriorates due to a decrease in engine response, or when the engine response is prioritized, a sufficient fuel consumption reduction effect cannot be obtained. was there.

  The present inventors have found that most of the situations where the VTC actuator is required to operate at high speed are when the specific cam phase (the most retarded angle phase and the most advanced angle phase) is established due to the rapid acceleration / deceleration operation of the engine. In this case, the VTC actuator is in the abutting state (because it does not act on the retard side or the advance side), so there is no need to perform the above-described phase control based on the target cam phase, and the speed control can be performed with a predetermined target angular velocity. I found something good. However, when the specific cam phase is established by speed control, since a large hydraulic pressure is continuously applied to the VTC actuator, it is necessary to reduce the hydraulic pressure once when shifting to phase control. It is inevitable that the engine response will be reduced due to.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a cam phase variable internal combustion engine that realizes an improvement in control response.

  A first invention is a cam phase variable internal combustion engine in which a cam phase is variably controlled within a predetermined angle range, and a first rotating member that rotates in synchronization with a crankshaft and a camshaft rotate together. A second rotating member connected to the first rotating member so as to be relatively rotatable, and an advance side oil chamber and a retarded side oil chamber formed between the first rotating member and the second rotating member. A cam phase switching means for shifting the cam phase between advance angle, retard angle and holding by switching the operating oil circuit, a driving operation state detecting means for detecting a driving operation state by the driver, and an engine operating state An engine operating state detecting means for detecting the engine operating state, a target angular velocity is set from at least one of the operating state detection result and the engine operating state detection result, and the cam phase change speed is controlled based on the target angular velocity. A speed control means, a phase control means for setting a target cam phase based on at least one of the previous operation operation state detection result and the engine operation state detection result, and controlling the cam phase based on the target cam phase; and the operation operation Control selection means for selecting one of the speed control and the phase control based on at least one of the detection result of the state detection means and the detection result of the engine operating state detection means, and determines the end of the speed control A speed control end determining means that performs the holding control to hold the cam phase at the end of the speed control with a predetermined urging force when the speed control end determining means determines that the speed control has ended. And a control means.

  According to a second aspect of the present invention, in the cam phase variable internal combustion engine according to the first aspect of the invention, the phase control includes a holding control amount learning means for sequentially learning a holding control amount for holding the cam phase. The holding control means sets the urging force by adding an additional control amount in the speed control direction to the holding control amount.

  According to a third aspect of the present invention, in the cam phase variable internal combustion engine according to the first or second aspect of the invention, when the holding control means determines that the speed control is finished by the speed control end judging means, The control amount is gradually decreased by a predetermined gradual decrease amount from the control amount at the end of the control toward the control amount that gives the urging force.

  According to a fourth invention, in the cam phase variable internal combustion engine according to the first to third inventions, the control selection means selects the speed control means at the time of sudden acceleration or sudden deceleration. .

  According to a fifth invention, in the cam phase variable internal combustion engine according to the first to fourth inventions, the control selection means includes at least one of an engine rotation speed, an engine load and an actual cam phase, and a required torque change speed. Based on the above, the selection is performed.

  According to a sixth invention, in the cam phase variable internal combustion engine according to the first to fifth inventions, the control selection means selects the speed control means when the increasing speed of the engine load is high. And

  According to a seventh aspect of the present invention, in the cam phase variable internal combustion engine according to the first to sixth aspects of the present invention, the control selection means sets the speed control means when the difference between the target cam phase and the actual cam phase is large. It is characterized by selecting.

  According to an eighth aspect of the present invention, in the cam phase variable internal combustion engine according to the first to seventh aspects of the present invention, the control selecting means has an actual cam phase in the vicinity of butting and a change speed of the actual cam phase is predetermined. The variable cam phase internal combustion engine according to any one of claims 1 to 7, wherein the phase control means is selected when the value falls below the value.

  According to a ninth invention, in the cam phase variable internal combustion engine according to the first to eighth inventions, the speed control means executes feedback control including an integral term, and the speed control means includes the control selection means. When the phase control means is selected by the above, the integral term is stopped.

  According to a tenth aspect of the present invention, in the cam phase variable internal combustion engine according to the first to ninth aspects, the speed control means includes at least one of an engine rotational speed, an engine load, and an actual cam phase, and a required torque change speed. The speed target value is set based on the above.

  An eleventh aspect of the invention is the cam phase variable internal combustion engine according to the tenth aspect of the invention, wherein the speed control means is based on at least one of an engine rotational speed, an engine load and an actual cam phase, and a required torque change speed. Then, the required air amount change speed is calculated, and the speed target value is set based on the required air amount change speed.

  According to a twelfth aspect of the present invention, in the cam phase variable internal combustion engine according to the first to eleventh aspects of the invention, the phase control means executes feedback control including an integral term, and the phase control means is the control selection means. When the speed control means is selected by the above, the integral term is stopped.

  According to a thirteenth aspect of the present invention, in the cam phase variable internal combustion engine according to the first to twelfth aspects of the invention, the phase control means sets a phase target value based on the engine speed and the required torque. And

  Further, a fourteenth aspect of the invention is the cam phase variable internal combustion engine according to the first to thirteenth aspects of the present invention, further comprising driving mode switching means for selecting one of driving modes including a fuel efficiency priority mode by the driver, When the fuel efficiency priority mode is selected by the driver, a threshold value for switching from the phase control to the speed control is increased.

  According to a fifteenth aspect, in the cam phase variable internal combustion engine according to the first to fourteenth aspects, the cam phase switching means is driven by a linear solenoid, and the resistivity compensates for a change in the resistivity of the linear solenoid. Compensating means is further provided.

  According to the present invention, at the time of rapid acceleration / deceleration, it is possible to quickly operate to the most retarded angle state or the most advanced angle state by speed control. Further, since the mode is shifted to the holding mode at the end of the speed control, a control delay hardly occurs when the phase control is started, and a decrease in engine response or the like is suppressed. In addition, in the case of sequentially learning the holding control amount for holding the cam phase, the holding control amount can be made to follow the change in the operating characteristic of the phase control means due to the engine oil temperature or the like. Also, when the speed control or phase control is stopped, the control deviation of the feedback control is set to 0 and the integration mechanism is also stopped, so that an excessive control amount is not output when switching between the speed control and the phase control. Smoothing is realized. Further, in the case of compensating the target control input according to the resistivity of the linear solenoid, the cam phase switching means can be driven and controlled with higher accuracy.

It is a principal part perspective view of the engine which concerns on embodiment. It is a disassembled perspective view of the VTC actuator which concerns on embodiment. It is a schematic block diagram of the VTC actuator which concerns on embodiment. 1 is a schematic configuration diagram of an engine ECU according to an embodiment. It is a mimetic diagram showing advance angle operation of the VTC actuator concerning an embodiment. It is a schematic diagram which shows the retardation operation | movement of the VTC actuator which concerns on embodiment. It is a schematic diagram which shows holding | maintenance operation | movement of the VTC actuator which concerns on embodiment. It is a schematic diagram which shows the operation | movement at the time of a failure of the VTC actuator which concerns on embodiment. It is a flowchart which shows the procedure of the target control input setting control which concerns on embodiment. It is a flowchart which shows the procedure of the driver request | requirement determination process which concerns on embodiment. 3 is a pedal opening-required torque map according to the embodiment. It is a flowchart which shows the procedure of the control selection process which concerns on embodiment. It is an operating point condition determination map on the acceleration side according to the embodiment. It is an operating point condition determination map on the deceleration side according to the embodiment. It is a control determination map concerning an embodiment. It is a flowchart which shows the procedure of the phase control stop process which concerns on embodiment. It is a flowchart which shows the procedure of the speed control completion | finish determination process which concerns on embodiment. It is a flowchart which shows the procedure of the speed target value setting process which concerns on embodiment. It is a request | requirement air amount change speed map which concerns on embodiment. It is a speed target value map concerning an embodiment. It is a flowchart which shows the procedure of the speed input value calculation process which concerns on embodiment. It is a FF target current map concerning an embodiment. It is a flowchart which shows the procedure of the main control input value setting process which concerns on embodiment. It is a flowchart which shows the procedure of the holding | maintenance input value learning process which concerns on embodiment. It is a flowchart which shows the procedure of the speed control stop process which concerns on embodiment. It is a flowchart which shows the procedure of the phase control transfer determination process which concerns on embodiment. It is a flowchart which shows the procedure of the phase target value setting process which concerns on embodiment. It is a steady fuel consumption optimal point map which concerns on embodiment. It is an operating point condition determination map on the acceleration side according to the embodiment. It is an operating point condition determination map on the deceleration side according to the embodiment. It is a flowchart which shows the procedure of the phase input value calculation process which concerns on embodiment. It is a graph which shows the effect | action of the speed control which concerns on embodiment. It is a graph which shows the effect | action of the holding | maintenance mode which concerns on embodiment.

  Hereinafter, an embodiment of a cam phase variable internal combustion engine according to the present invention will be described in detail with reference to the drawings.

<< Configuration of Embodiment >>
<Overall configuration>
An engine (cam phase variable internal combustion engine) E shown in FIG. 1 is a DOHC 4-valve four-cycle in-line four-cylinder gasoline engine mounted on an automobile. An intake valve 2 for each cylinder is provided in the cylinder head 1. And an exhaust valve 3, an intake camshaft 4 and an exhaust camshaft 5 that drive the intake and exhaust valves 2 and 3. Both camshafts 4 and 5 are rotationally driven by the crankshaft 10 at a rotational speed of 1/2 through the crank sprocket 6, the cam chain 7, the intake cam sprocket 8, and the exhaust cam sprocket 9. The crankshaft 10 is connected to the piston 12 via a connecting rod 11 and drives an oil pump 14 installed obliquely downward via a chain 13.

  A VTC actuator 21 is attached to the front end of the intake camshaft 4. The cylinder head 1 and the cylinder block 15 are formed with a hydraulic oil supply oil passage 16 for supplying hydraulic oil (engine oil) from the oil pump 14 to the VTC actuator 21. The cylinder head 1 is provided with a normally open type electromagnetic shut valve 17, and the operation of supplying the working oil to the VTC actuator 21 is switched by operating the electromagnetic shut valve 17. An intake side cam angle sensor 18 is installed at the rear end of the intake camshaft 4. In the present embodiment, the operating range of the VTC actuator 21 is 0 ° to 70 ° between the advance side and the retard side.

  In the passenger compartment, an intake side cam angle sensor 18 and an accelerator pedal sensor 19, an ECON switch 20 for the driver to select one of a plurality of operation modes including a fuel efficiency priority mode, and various sensors (intake air amount sensor) , Intake pressure sensor, crank angle sensor, water temperature sensor, etc.) of various controlled devices (electromagnetic shut valve 17, VTC actuator 21, unillustrated fuel injection valve, ignition coil, etc.) attached to engine E An engine ECU 70 that determines a control amount and outputs a drive current is installed.

<VTC actuator>
As shown in FIG. 2, the VTC actuator 21 includes a housing (first rotating member) 22 having an intake cam sprocket 8 formed on the outer periphery thereof, is rotatably held in the housing 22, and is then attached to the front end of the intake camshaft 4. A rotor (second rotating member) 23 to which the surface is fastened, a front plate 24 covering the front surface of the housing 22, a back plate 25 covering the rear surface of the housing 22, a reed valve 26 disposed on the inner peripheral side of the front plate 24, a lead By being controlled by a reed valve cover 27 for fixing the valve 26 to the rotor 23, a bias spring 28 for relatively rotating the housing 22 and the rotor 23 in the advance direction, a spool valve 29 installed at the shaft center, and an engine ECU. Linear solenoid 31 for driving the spool valve 29, rotor 3, a lock pin spring 34 that biases the lock pin 33 toward the back plate 25, a bypass valve 36 that is retained by the rotor 23, and a bypass valve that biases the bypass valve 36 toward the back plate 25. The spring 37 or the like is a constituent element. The spool valve 29 includes a valve sleeve 38 held at the axis of the intake camshaft 4 and the rotor 23, a spool 39 slidably fitted in the valve sleeve 38, and the spool 39 attached to the linear solenoid 31 side. And a return spring 40 that is energized.

  As shown in FIG. 3, the first to third vanes 41 to 43 are erected on the outer periphery of the rotor 23, while the vanes 41 to 43 are placed on the inner periphery of the housing 22 at a relative angle of 0 ° to 70 °. First to third vane chambers 45 to 47 are formed, which allow displacement and are rotatably accommodated. In the case of this embodiment, the first vane 41 and the first vane chamber 45 are components of a first hydraulic pressure actuated phase variable mechanism (hereinafter referred to as OPA), and the second vane 42 and the second vane 42 The vane chamber 46 is a component of the second OPA 62, and the third vane 43 and the third vane chamber 47 are components of a cam torque driven phase variable mechanism (hereinafter referred to as CTA) 63.

  The third vane 43 accommodates a bypass valve 36 and a bypass valve spring 37 (see FIG. 2). The first vane 41 accommodates a lock pin 33 and a lock pin spring 34 (see FIG. 2), and the back plate 25 has a lock hole 25a into which the lock pin 33 is fitted. In the case of the embodiment, the lock pin 33 and the bypass valve 36 are arranged such that the centrifugal force accompanying the rotation of the intake camshaft 4 hardly acts during operation of the engine E so that the shaft center of the VTC actuator 21 (that is, the intake camshaft 4 It is installed parallel to the axis). In FIG. 3, a member denoted by reference numeral 49 is a rotor-side seal provided on the outer periphery of the rotor 23, and a member denoted by reference numeral 50 is a housing-side seal provided on the inner periphery of the housing 22.

  The first and second vane chambers 45 and 46 have an OPA side advance angle to which hydraulic oil from the spool valve 29 is supplied via the OPA side advance oil passages 51 and 52 by the first and second vanes 41 and 42. Chambers 45a, 46a and OPA-side retarded chambers 45b, 46b into which hydraulic oil from the spool valve 29 is supplied via OPA-side retarded oil passages 53, 54, by first and second vanes 41, 42. Each is partitioned. The third vane chamber 47 includes a CTA-side advance chamber 47 a that communicates with the spool valve 29 via the first CTA oil passage 56 and a CTA-side retard chamber that communicates with the spool valve 29 via the second CTA oil passage 55. It is partitioned by the third vane 43 into 47b. Further, the OPA side advance oil passages 51 and 52 are connected to the electromagnetic shut-off valve 17 via the hydraulic oil discharge passages 81 to 83 as shown in FIGS.

  The first vane 41 accommodates a lock pin 33 and a lock pin spring 34 (see FIG. 2), and only when the hydraulic oil is not supplied to the lock pin release oil passage, The tip of the lock pin 33 is fitted into the lock hole 25 a formed in the back plate 25 by the spring force. Note that the lock hole 25a is formed at a position where the lock pin 33 is fitted when the rotor 23 reaches the start cam phase (in this embodiment, the most retarded angle phase) with respect to the housing 22.

<Engine ECU>
As shown in FIG. 4, the engine ECU 70 includes an input interface 71, a high-level command unit 72, a cam phase change speed estimation unit 73, a phase control unit 74, a speed control unit 75, and a holding mode control unit 76. A holding input value learning unit 77, a control selection unit 78, a resistivity compensation unit 79, and an output interface 80 are provided.

  In addition to the accelerator opening (driving operation state amount) input from the accelerator pedal sensor 19 and the operation mode selection signal input from the ECON switch 20, the input interface 71 includes engine operation such as intake air amount, cooling water temperature, and engine speed Ne. The state quantity and the detection signal of the intake cam angle sensor 18 are input. The upper command unit 72 sets the phase control target value and the speed control target value of the VTC actuator 21 based on the above-described driving operation state quantity and engine operating state quantity, and performs speed control, phase control, and holding mode control. Either is selected and a selection command is output to the control selection unit 78. The cam phase change speed estimation unit 73 estimates the cam phase change speed of the VTC actuator 21 based on the change (time differential value) of the actual cam phase detected by the intake cam angle sensor 18. The phase control unit 74 sets the first drive voltage output to the VTC actuator 21 based on the phase control target value and the actual cam phase. The speed control unit 75 sets the second drive voltage to be output to the VTC actuator 21 based on the speed control target value and the cam phase change speed. The holding mode control unit 76 sets the third drive voltage to be output to the VTC actuator 21 based on the speed control end timing, the actual cam phase, and the holding input value. The control selection unit 78 selects one of the first drive voltage, the second drive voltage, and the third drive voltage as the target drive voltage based on the selection command. The resistivity compensator 79 estimates the resistivity of the linear solenoid 31 based on the supplied current and voltage, and compensates the resistivity of the target drive voltage. A target drive voltage is output from the output interface 80 to the VTC actuator 21.

<< Operation of Embodiment >>
During operation of the engine E, the engine ECU 70 repeatedly executes drive control of the VTC actuator 21 at a predetermined control interval (for example, 5 ms). When the drive control is started, the engine ECU 70 determines the speed control target value and the phase control target value of the intake camshaft 4 based on the driving operation state quantity and the engine operation state quantity, and then sets the drive voltage for realizing these values to the VTC. An appropriate output is made to the linear solenoid 31 of the actuator 21.

<Operation mode of VTC actuator>
(Advanced operation)
When the intake camshaft 4 is advanced during operation of the engine E, the engine ECU 70 is spooled by the linear solenoid 31 in a state where the hydraulic oil supply oil passage 16 is communicated by the electromagnetic shut valve 17 as shown in FIG. 39 is moved in the advance direction (rightward in the figure). Then, the hydraulic oil supplied from the oil pump 14 via the hydraulic oil supply oil passage 16 holds the lock pin 33 in the released state, and advances on the first and second OPA 61 and 62 side via the spool valve 29. The air flows into the corner side hydraulic chambers 45a and 46a and urges the first and second vanes 41 and 42 toward the advance side. During normal operation of the engine E, no drive current is supplied to the electromagnetic shut-off valve 17 (the hydraulic oil supply oil passage 16 is communicated), and the lock pin 33 is held in the released state by the hydraulic oil from the oil pump 14. On the other hand, in the CTA 63, the cam angle on the advance side acts on the intake camshaft 4, and the second valve body 26b of the reed valve 26 opens each time the rotor 23 rotates relative to the housing 22 toward the advance side. The hydraulic oil in the side hydraulic chamber 47 b flows into the advance side hydraulic chamber 47 a through the spool valve 29. Further, when the retard side cam torque is applied, the first and second valve bodies 26a, 26b of the reed valve 26 are closed, and the cam phase is maintained without moving the hydraulic oil. By the operations of the first and second OPAs 61 and 62 and the CTA 63, the rotor 23 rotates relative to the housing 22 in the clockwise direction in the drawing, and the intake camshaft 4 advances. The hydraulic oil is supplied to the CTA 63 until the CTA 63 is satisfied at the start of operation of the engine E.

(Retarded operation)
When retarding the intake camshaft 4 during operation of the engine E, the engine ECU 70 moves the spool 39 in the retarding direction (leftward in the figure) by the linear solenoid 31 as shown in FIG. Then, the hydraulic oil supplied from the oil pump 14 via the hydraulic oil supply oil passage 16 flows into the OPA side retard chambers 45b and 46b via the spool valve 29 and the OPA side retard oil passages 53 and 54. The first and second vanes 41 and 42 are rotated relative to the retard side. The hydraulic oil in the OPA side advance chambers 45a and 46a is discharged to the outside from the right side of the spool 39 via the OPA side advance oil passages 51 and 52. On the other hand, in the CTA 63, the first CTA oil passage 56 and the central oil passage 57 communicate with each other through the spool valve 29 in which the spool 39 is moved to the retard position. Then, the retard cam torque acts on the exhaust camshaft 5 and the first valve body 26a of the reed valve 26 opens each time the rotor 23 rotates relative to the housing 22 toward the retard side, and the CTA side advance chamber is opened. The hydraulic oil in 47a flows into the CTA side retard chamber 47b and relatively rotates the third vane 43 to the retard side. Further, when the cam torque on the advance side acts, the first and second valve bodies 26a, 26b of the reed valve 26 are closed, and the cam phase is maintained without moving the hydraulic oil.

(Holding operation)
When the target cam phase is obtained by the advance angle operation or the retard angle operation described above, the engine ECU 70 moves the spool 39 to the holding position (center in the figure) by the linear solenoid 31 as shown in FIG. Then, in the first and second OPAs 61 and 62, the hydraulic oil in the advance side hydraulic chambers 45a and 46a is sealed by the spool valve 29, and the first and second vanes 41 and 42 cannot move. On the other hand, in the CTA 63, the hydraulic oil cannot move between the advance side hydraulic chamber 47a and the retard side hydraulic chamber 47b, and the third vane 43 cannot move. By the operations of the first and second OPAs 61 and 62 and the CTA 63, the rotor 23 does not rotate relative to the housing 22, and the cam phase of the intake camshaft 4 is maintained.

(Operates during failure)
When the linear solenoid 31 is disconnected or the spool valve 29 is stuck and the cam phase cannot be controlled, the engine ECU turns on an abnormal warning light installed on the instrument panel and restarts the engine E. Sometimes the current is supplied to the electromagnetic shut-off valve 17.

  As shown in FIG. 8, when the spool valve 29 is fixed at, for example, a retarded position, in the first and second OPAs 61 and 62, in addition to leakage from between the housing 22 and the rotor 23, the hydraulic oil supply oil passage 16 and the electromagnetic shut-off valve 17, the hydraulic oil in the OPA side advance chambers 45 a and 46 a is discharged to the outside of the VTC actuator 21. In the CTA 63, the hydraulic oil that has been supplied to the bypass valve 36 is discharged from the electromagnetic shut valve 17. As a result, the bypass valve 36 is moved to the back plate 25 side (upward in FIG. 8) by the spring force of the bypass valve spring 37 to become a fail position, and the communication oil passages 43c and 43d and the communication groove 36a of the bypass valve 36 are connected. Accordingly, the hydraulic oil in the CTA side advance chamber 47a flows into the CTA side retard chamber 47b. Further, in the first vane 41, the hydraulic oil that has been supplied to the lock pin 33 is discharged from the electromagnetic shut valve 17. As a result, the lock pin 33 is biased toward the back plate 25 (upward in FIG. 8) by the spring force of the lock pin spring 34, and the lock pin 33 can be fitted into the lock hole 25a. As a result, the rotor 23 and the housing 22 intermittently rotate relative to each other due to the cam torque received by the intake camshaft 4, and at the moment when the fail cam phase (in this embodiment, the most retarded angle phase) is reached, the lock pin 33 is locked. 25a.

<Target control input setting control>
The engine ECU 70 sets the target cam phase CAtgt and the required cam phase change speed CAcmd ′ based on the driving operation state quantity and the engine operating state quantity, and then sets the target control input to the VTC actuator 21 according to the procedure shown in the flowchart of FIG. The control is repeatedly executed at a predetermined control cycle (5 ms in the present embodiment).

(Resistivity estimation processing)
When the target control input setting control is started, the engine ECU 70 estimates the resistivity Rhat of the linear solenoid 31 by the following equation in step S1 of FIG.
Rhat (Ak)
= Rhat (A (k-1)) + KP (A (k-1)). Eid (A (k-1))
Here, k is a control period (5 ms), A is a coefficient (200 in the present embodiment) for allowing a delay due to inductance or the like to be ignored, and Ak is 1,000 ms (1 sec).
KP is a learning gain, and is obtained from the driving current I of the linear solenoid 31 and the identification gain P by the following equation using the sequential least square method.
KP (A (k-1))
= P · ζ / (1 + ζ ^T (A (k-1)) · P · ζ (A (k-1)))
= P · I (A (k−1)) / (1 + I ² (A (k−1)) · P)
On the other hand, eid is an estimation error, and is obtained from the final input voltage Ufinal to the linear solenoid 31, the drive current I, and the resistivity Rhat by the following equation.
eid (A (k-1))
= Ufinal (A (k-1))-I (A (k-1)). Rhat (A (k-1))

(Driver request determination processing)
Next, in step S2, the engine ECU 70 executes a driver request determination process whose procedure is shown in the flowchart of FIG. When the driver request determination process is started, the engine ECU 70 obtains the target required torque TRQcmd from the pedal opening-required torque map of FIG. 11 based on the accelerator pedal opening AP input from the accelerator pedal sensor 19 in step S41 of FIG. After searching / setting, it is determined in step S42 whether or not the engine E is in the rapid acceleration / deceleration state based on the current value TRQcmd (k) and the previous value TRQcmd (k-1) of the target required torque TRQcmd. If this determination is Yes, the engine ECU 70 sets the rapid acceleration / deceleration flag Fgun to 1 in step S43, whereas if it is No, the engine ECU 70 sets the rapid acceleration / deceleration flag Fgun to 0 in step S44 and ends the driver request determination process. In the case of the present embodiment, the engine ECU 70 determines that it is in the rapid acceleration / deceleration state when one of the following formulas (1) and (2) and the following formula (3) are satisfied simultaneously.
TRQcmd (k) <Tlow (1)
TRQcmd (k)> High (2)
| TRQcmd '|> Dtlim (3)
Here, Tlow is a low torque determination threshold, High is a high torque determination threshold, TRQcmd ′ is a required torque change rate (TRQcmd (k) −TRQcmd (k−1)), and Dtlim is a torque change determination threshold.

(Control selection process)
Next, in step S3 of FIG. 9, the engine ECU 70 executes a control selection process whose procedure is shown in the flowchart of FIG. When the control selection process is started, the engine ECU 70 determines whether or not the rapid acceleration / deceleration flag Fgun is 1 in step S51 of FIG. 12. If this determination is No, the engine ECU 70 sets the phase control flag Fpc to 1 in step S52. Then, the control selection process is terminated.

  On the other hand, if the determination in step S51 is Yes, the engine ECU 70 determines whether the engine operating state (required torque change rate TRQcmd ′ and load increase / decrease (eg, Brake Mean Effective Pressure: hereinafter BMEP) in step S53. The engine operating point is determined using the operating point condition determination map shown in Fig. 13 and Fig. 14. Fig. 13 shows the operating point condition determination map on the acceleration side, and Fig. 14 shows the operation on the deceleration side. These are point condition determination maps, both of which have a larger required torque change rate TRQcmd ′ set in the speed control region and a smaller required torque change rate TRQcmd ′ set in the phase control region. In order to prevent control hunting between the point condition determination map and the operating point condition determination map on the deceleration side, a predetermined hysteresis It is provided.

  Next, in step S54, the engine ECU 70 determines whether or not the engine operating point is in the speed control region. If this determination is No (that is, if the engine operating point is in the phase control region), step S52. Thus, the phase control flag Fpc is set to 1 and the control selection process is terminated.

  On the other hand, if the determination in step S54 is Yes, the engine ECU 70 uses the control determination map of FIG. 15 based on the cam phase state (required cam phase change speed CAcmd ′ and cam phase difference ΔCA) in step S55. Make a control decision. Here, the cam phase difference ΔCA is the absolute value of the difference between the actual cam phase CA input from the intake side cam angle sensor 18 and the target cam phase CAtgt (ΔCA = | CA−CAtgt |). In the control determination map, the side with the larger cam phase state is set as the speed control region, and the side with the smaller cam phase state is set as the phase control region.

  Next, in step S56, the engine ECU 70 determines whether or not the cam phase state is in the speed control region, and if this determination is No (that is, if the cam phase state is in the phase control region), step S52. Thus, the phase control flag Fpc is set to 1 and the control selection process is terminated.

  If the determination in step S56 is also Yes (that is, if the cam phase state is also in the speed control region), the engine ECU 70 sets the speed control flag Fvc to 1 in step S57 and ends the control selection process.

  Next, the engine ECU 70 determines whether or not to speed-control the VTC actuator 21 (that is, whether or not the speed control flag Fvc is 1) in step S4 of FIG. If this determination is Yes, the engine ECU 70 executes a phase control stop process whose procedure is shown in the flowchart of FIG. 16 in step S5.

(Phase control stop processing)
When the phase control stop process is started, the engine ECU 70 sets a phase control deviation e (k) in a phase input value calculation process, which will be described later in step S61 of FIG. 16, to 0, and a disturbance estimation error in the phase input value calculation process in step S62. Kp · edobs (k) is set to 0 (the disturbance estimation integral mechanism (integral term) is stopped). Thereby, when the phase control is started again, an excessive output due to the operation of the integration mechanism or the like is not generated.

(Speed control end judgment process)
Next, in step S6, the engine ECU 70 executes speed control end determination processing whose procedure is shown in the flowchart of FIG. When the speed control end determination process is started, the engine ECU 70 determines in step S71 in FIG. 17 whether or not the speed control has been performed during the previous process, and if this determination is No (from phase control to speed control). In step S72, the speed control end flag Fvcend is set to 0. If the determination in step S71 is Yes (that is, if the current speed control is in progress), the engine ECU 70 determines in step S73 whether or not it is in the vicinity of an abutment in the required operation direction. If the determination is No, the speed control end flag Fvcend is set to 0 in step S72.

  In the present embodiment, the determination in step S73 is Yes when the previous speed target value is positive (that is, when driving in the retarded direction) and 65 ° <CA <75 ° is satisfied, and the previous speed When the target value is negative (that is, when the target value is driven in the advance direction), Yes is satisfied when −5 ° <CA <5 ° is satisfied. The reason why the determination of the vicinity of the abutment is given a range of ± 5 ° is that there is a product error or an assembly error in the constituent elements of the VTC actuator 21 or that the abutment position changes due to long-term operation. .

  If the determination in step S73 is Yes (that is, if the VTC actuator 21 is in the vicinity of a collision), the engine ECU 70 determines in step S74 whether the operating speed Vvtc of the VTC actuator 21 is equal to or less than a predetermined threshold value Vth. If this determination is No, the speed control end flag Fvcend is set to 0 in step S72. In the present embodiment, the operating speed Vvtc is obtained from the difference between the current value CA (k) and the previous value CA (k) of the actual cam phase CA, but may be obtained by a pseudo-differential method, a speed observer, or the like. .

  If the determination in step S74 is also “Yes”, the engine ECU 70 assumes that the VTC actuator 21 has entered a collision state, sets the speed control flag Fvc to 0 and sets the speed control end flag Fvcend to 1 in step S75.

  Next, in step S7 of FIG. 9, the engine ECU 70 determines whether or not the speed control has ended (whether or not the speed control end flag Fvcend is 1). If this determination is No, the engine ECU 70 determines in step S8. A speed target value setting process whose procedure is shown in the flowchart of FIG. 18 is executed.

(Speed target value setting process)
When the speed target value setting process is started, the engine ECU 70 acquires various engine parameters in step S81 in FIG. 18, and then in step S82, based on the required torque change rate TRQcmd ′ and the engine speed Ne, the required air in FIG. The requested air amount change speed SAcmd ′ is searched / set from the amount change speed map. Next, in step S83, the engine ECU 70 retrieves / sets the speed target value DCAcmd (k) from the speed target value map of FIG. 20 based on the required air amount change speed SAcmd ′, the intake pipe pressure Pb, and the engine speed Ne. After that, in step S84, the speed target value DCAcmd (k) is filtered. The difference in the speed target value DCAcmd (k) depending on the intake pipe pressure Pb may be obtained by calculation instead of the required air amount change speed map.

(Speed input value calculation process)
Next, in step S9 of FIG. 9, the engine ECU 70 executes a speed input value calculation process whose procedure is shown in the flowchart of FIG. When the speed input value calculation process is started, the engine ECU 70, based on the speed target value DCAcmd (k), in step S91 in FIG. 21, the target input current for FF (feed forward) from the FF target current map in FIG. Hereinafter, Ucrnt (k) (referred to as FF target current) is searched / set. In the FF target current map, the value of the FF target current Ucrnt (k) is changed according to the engine parameters (such as the engine oil temperature To and the engine rotational speed Ne) that affect the operation characteristics of the linear solenoid 31. This may be performed by learning.

Next, in step S92, the engine ECU 70 calculates a speed control FF term Udff (k) from the FF target current Ucrnt (k) and the resistivity Rhat (k) by the following equation.
Udff (k) = Ucrnt (k) · Rhat (k)

Next, in step S93, the engine ECU 70 calculates the speed control FB term Udfb (k) by the following procedure.
First, the engine ECU 70 obtains a speed control deviation ed (k) from the speed target value DCAcmd (k) and the actual speed DCA (k) by the following equation.
ed (k) = DCAcmd (k) −DCA (k)
Next, the engine ECU 70 obtains an enlarged speed control deviation σd (k) from the current and previous speed control deviations ed (k), ed (k−1) and the response designation parameter Pole by the following equation.
σd (k) = ed (k) + Pole · ed (k−1)
Next, the engine ECU 70 obtains the speed control FB raw value Udftemp (k) from the enlarged speed control deviation σd (k) and the feedback gains Kp, Kadp by the following equation.
Udftemp (k) = Kp · σd (k) + Kadp · Σσd (k)
Thereafter, the engine ECU 70 obtains the speed control FB term Udfb (k) from the speed control FB raw value Udftemp (k), the resistivity Rhat (k), and the resistivity initial value Rbase by the following equation.
Udfb (k) = (Rhat (k) / Rbase) · Udftemp (k)

Finally, in step S94, the engine ECU 70 calculates a speed control input value Ud (k) from the speed control FF term Udff (k) and the speed control FB term Udfb (k) by the following equation.
Ud (k) = Udff (k) + Udfb (k)

(Main control input value setting process)
Next, in step S10 of FIG. 9, the engine ECU 70 executes main control input value setting processing whose procedure is shown in the flowchart of FIG. When the main control input value setting process is started, the engine ECU 70 determines in step S101 in FIG. 23 whether or not at least one of the speed control end flag Fvcend or a holding mode flag Fcnstmd described later is 1, and this determination is made. If No, the control input value Uctr (k) is directly used as the main control input value Umain (k) in step S102. The control input value Uctr (k) is the speed control input value Ud (k) described above or a phase control input value Up (k) described later.
Umain (k) = Uctr (k)

On the other hand, if the speed control end flag Fvcend or the holding mode flag Fcnstmd is 1, and the determination in step S101 is Yes, the engine ECU 70 determines in step S103 whether the current input value Utemp is smaller than a predetermined determination threshold value Uth. To do. If the determination in step S103 is No, the engine ECU 70 calculates the main control input value Umain (k) by the following equation.
Umain (k) = λUtemp (k−1) + Uoft (k)
Here, λ (0 <λ <1) is a forgetting factor, and Uof (k) is a minute value in the abutting direction of the VTC actuator 21. As a result, when the speed control end flag Fvcend or the holding mode flag Fcnstmd becomes 1 (that is, when the speed control is ended), the main control input value Umain (k) gradually decreases from the end of the speed control. .

  When the main control input value Umain (k) decreases and the determination in step S103 becomes Yes, the engine ECU 70 sets the speed control end flag Fvcend to 0 and sets the holding mode flag Fcnstmd to 1 in step S105. Thus, when a predetermined time has elapsed from the end of speed control, the rotor 23 of the VTC actuator 21 is pressed in the abutting direction with a slight pressing force.

(Target control input value calculation process)
When the main control input value setting process ends, the engine ECU 70 calculates a target control input value U (k) using the following equation in step S11 of FIG.
U (k) = Uctr (k) + Umain (k)
Here, Uctr (k) is a holding input and is set by the procedure described below.

<Holding input value learning process>
In parallel with the target control input setting control, the engine ECU 70 repeatedly executes a holding input value learning process whose procedure is shown in the flowchart of FIG. 24 at a predetermined control cycle (1 sec in this embodiment). When the holding input value learning process is started, the engine ECU 70 determines whether or not phase control is being performed in step S211 of FIG. 24. If this determination is No, the engine ECU 70 returns to the start without performing holding input learning.

  If the current phase control is in progress and the determination in step S211 is Yes, the engine ECU 70 determines in step S212 whether the operating speed Vvtc of the VTC actuator 21 is equal to or lower than a predetermined threshold value Vth. If so, return to the start without holding input learning. When the operating speed Vvtc is equal to or lower than the threshold value Vth, the VTC actuator 21 is hardly operated (that is, the holding state).

  When the VTC actuator 21 is in the holding state and the determination in step S212 is Yes, the engine ECU 70 determines in step S213 whether or not the VTC actuator 21 is in the vicinity of the abutment. Return to the start without holding input learning. In the present embodiment, the determination in step S213 is Yes when 5 ° <CA <65 ° is satisfied.

If the VTC actuator 21 is not near the bump and the determination in step S213 is No, the engine ECU 70 learns the holding input Uctr (k) from the following equation in step S214. Here, Uctrint is a holding input initial value, and α (Ak) is a learning value.
Uctr (k) = Uctrint + α (Ak)

The learning value α (Ak) is calculated by the following equation.
α (Ak) = α (A (k−1)) + KP (Ak) · eid (Ak)
Here, k is a control period (5 ms), A is a coefficient (200 in the present embodiment) for allowing a delay due to inductance or the like to be ignored, and Ak is 1,000 ms (1 sec).
KP is a learning gain, and is obtained from the drive current I of the linear solenoid 31 and the identification gain P by the following equation using the fixed gain method.
KP (Ak)
= P · ζ / (1 + ζ ^T (Ak) · P · ζ (Ak))
= P / (1 + P)
On the other hand, eid is calculated by the following equation so that the phase control input becomes zero.
eid (Ak) = Umain (Ak)

(Speed control stop process)
When the speed control ends (speed control end flag Fvcend becomes 1) and the determination in step S7 of FIG. 9 becomes Yes, the engine ECU 70 performs speed control whose procedure is shown in the flowchart of FIG. 25 in step S12. Execute stop processing. When the speed control stop process is started, the engine ECU 70 sets the speed control deviation ed (k) in the speed input value calculation process described above in step S111 of FIG. 25 to 0, and also in step S112, the feedback gain Kadp in the phase input value calculation process. Is set to 0 (the integration mechanism is stopped). Thereby, when the speed control is started again, an excessive output due to the operation of the integration mechanism or the like is not generated.

(Retention mode transition process)
When the speed control stop process is finished, the engine ECU 70 executes a holding mode transition process in step S13. That is, the speed control end flag Fvcend is set to 0, and the holding mode flag Fcnstmd is set to 1.

(Phase control transition judgment process)
When the speed control flag Fvc is 0 and the determination in step S4 of FIG. 9 is No, the engine ECU 70 determines in step S14 whether or not it is currently in the holding mode. If this determination is Yes, the engine ECU 70 executes a phase control transition determination process whose procedure is shown in the flowchart of FIG. 26 in step S15. When the phase control transition determination process is started, the engine ECU 70 determines whether or not a phase target value CAcmd (k) described later in step S121 in FIG. 26 is not near the abutment (5 ° <CAtgt <65 °). If this determination is No, the processing is terminated as it is, and if it is Yes, the holding mode flag Fcnstmd is set to 0 and the phase control flag Fpcr is set to 1 in step S122.

  Next, the engine ECU 70 determines whether or not the phase control is shifted to step S16 (that is, whether or not the phase control flag Fpcr is 1). If this determination is No, the holding mode is continued. Then, the process proceeds to step S10, and the aforementioned main control input value setting process and target control input value calculation process are executed.

(Phase target value setting process)
When the phase control flag Fpcr becomes 1 and the determination in step S16 becomes Yes, the engine ECU 70 executes a phase target value setting process whose procedure is shown in the flowchart of FIG. 27 in step S17. When the phase target value setting process is started, the engine ECU 70 acquires various engine parameters in step S131 in FIG. 27, and then in step S132, based on the BMEP and the engine speed Ne, the steady fuel efficiency optimum point map in FIG. To / from the phase target value CAcmd (k) of the VTC actuator 21.

  Next, in step S133, the engine ECU 70 determines whether the required torque change rate TRQcmd 'and the load increase / decrease (for example, increase / decrease in net mean effective pressure (hereinafter referred to as BMEP)) 29, the engine operating point is determined using the operating point condition determination map shown in Fig. 30. Fig. 29 is the operating point condition determining map on the acceleration side, and Fig. 30 is the operating point condition determining map on the deceleration side, The phase zero flag Fzero is set to 1 in the high change region where the required torque change rate TRQcmd ′ is large, and the phase holding flag Fcnst is set to 1 in the low change region where the required torque change rate TRQcmd ′ is small. In order to prevent control hunting and the like between the operating point condition determination map and the deceleration-side operating point condition determination map, a predetermined hysteresis It is provided.

  Next, in step S134, the engine ECU 70 determines whether or not the phase zero flag Fzero is 1. If this determination is Yes, the phase target value CAcmd (k) is set to 0 in step S135. If the determination in step S134 is No, the engine ECU 70 determines in step S136 whether or not the phase holding flag Fcnst is 1, and if this determination is Yes, in step S137 the phase target value CAcmd (k). To the previous value CAcmd (k−1).

  If the determination in step S136 is also No, the engine ECU 70 performs a filtering process on the phase target value CAcmd (k) set in step S132 in step S138.

(Phase input value calculation process)
Next, in step S18 of FIG. 9, the engine ECU 70 executes a phase input value calculation process whose procedure is shown in the flowchart of FIG. When the phase input value calculation process is started, the engine ECU 70 sets the phase control input Uphase by the following procedure in step S141 in FIG.

First, the engine ECU 70 predicts a cam phase prediction value CA (k + 1) using a cam phase prediction model shown in the following equation.
CA (k + 1) = a ₁ · CA (k) + a ₂ · CA (k−1) + b ₁ · Uphase (k)
+ B ₂ · Uphase (k-1) + c (k)
Here, a ₁ , a ₂ , b ₁ , b ₂ are model parameters, Uphase is a control input for phase control, and c is a disturbance estimation parameter.

Next, the engine ECU 70 calculates the control target phase value CAcmd_f (k) by the following equation using the followability designation parameter Pole _f (0 <Pole _{f_lf} <1).
CAcmd_f (k) = Pole _f · CAcmd_f (k−1)
+ (1-Pole _{f_lf} ) .CAcmd (k)

Next, the engine ECU 70 calculates the phase control deviation e (k) from the actual phase CA (k) and the control phase target value CAcmd_f (k) by the following equation.
e (k) = CA (k) −CAcmd_f (k)

Next, the engine ECU 70 calculates the phase control deviation current value e (k), the previous value e (k-1), and the response designation parameter Pole (-1 <Pole <0) according to the following formula to enlarge the phase control deviation σ. (K) is calculated.
σ (k) = e (k) + Pole · e (k−1)

Next, the engine ECU 70 uses the disturbance estimation error Kp · edobs (k) to calculate a disturbance estimated value c (k) using the following equation.
c (k) = c (k-1) + Kp · edobs (k)
Here, Kp and edobs (k) are obtained by the following equations, respectively.
Kp = P / (1 + P)
edobs (k) = CA (k) −CAhat (k)
CAhat (k) = a ₁ · CA (k−1) + a ₂ · CA (k−2) +
b ₁ · Uphase (k-1) + b ₂ · Uphase (k-2) + c (k-1)
In the present embodiment, the fixed gain method is used for estimating the feedback gain Kp, but other estimation methods such as a weighted least square method may be employed.

Next, the engine ECU 70 calculates a control input value Uphase (k) by the following equation based on the above-described cam phase prediction model.
Uphase (k) = Ueq (k) + Urch (k)
Here, Ueq (k) and Urch (k) are obtained by the following equations, respectively.
Ueq (k) = (1 / b ₁ ) · {(1-Pole-a ₁ ) · CA (k−1)
+ (Pole-a ₂ ) · CA (k−1) + CAcmd_f (k + 1) −c (k)
+ (Pole-1) · CAcmd_f (k) + Pole · CAcmd_f (k-1)
-B ₂ · Uphase (k-1)}
Urch (k) = (− Krch / b ₁ ) · σ (k)
edov (k) = Liftin (k)-Liftin_hat (k)

Next, in step S142, the engine ECU 70 performs resistivity compensation using the following expression from the control input value Uphase (k) and the previously obtained resistivity Rhat (k) of the linear solenoid 31.
Uphase_f (k) = (Rhat (k) / Rbase) · Uphase (k)

(Transition from speed control to hold mode)
If the determination in step S14 is No, the engine ECU 70 determines in step S19 whether phase control has been performed during the previous process. If the phase control has not been reached yet after the shift from the speed control, the determination in step S19 is No. Therefore, after executing the speed control stop process (FIG. 25) in step S20, the engine ECU 70 holds the above-described holding in step S21. Execute mode transition processing. As a result, when the speed control is started again, an excessive output due to the operation of the integrating mechanism or the like is not generated, and the main control input value Umain (k) gradually decreases from the end of the speed control.

(During phase control)
If the VTC actuator 21 is under phase control and the determination in step S19 is Yes, the engine ECU 70 executes speed control stop processing (FIG. 25) in step S22. Thereby, when the speed control is started again, an excessive output due to the operation of the integration mechanism or the like is not generated. Next, the engine ECU 70 executes a phase target value setting process (FIG. 27) in step S17 and a phase input value calculation process (FIG. 31) in step S18.

(Action of speed control)
When the target control input value U (k) based on the speed control input value Ud (k) is output to the linear solenoid 31 (that is, when the speed of the VTC actuator 21 is controlled), as shown by the solid line in the graph of FIG. In addition, the change speed (angular velocity) of the cam phase CA rises steeply, and the cam phase CA changes rapidly to the retard side or the advance side. FIG. 32 shows a state in which the cam phase CA changes to the retard side. From FIG. 32, when speed control based on the speed target value (shown by a solid line) is performed, phase control based on the phase target value is performed. It can be seen that the change of the cam phase CA to the most retarded position is realized without delay and in a short time compared to the case (indicated by a broken line).

(Operation of holding mode)
When the VTC actuator 21 shifts to the holding mode from the end of speed control, as shown in the graph of FIG. 33, the control input value U (k) while the cam phase CA is held at the most retarded position or the most advanced position. Becomes a small value obtained by adding a minute value to the held input value. Therefore, when the phase control is resumed, the cam phase CA changes more rapidly than in the case where the holding mode is not passed, and a decrease in engine response due to the control delay is effectively suppressed.

<< Effects of Embodiment >>
In the present embodiment, since the control input value U (k) of the linear solenoid 31 is calculated according to the procedure described above, the VTC actuator 21 is quickly brought into the most retarded state or the most advanced angle state by speed control during sudden acceleration / deceleration. Can be operated. In addition, the mode shifts to the holding mode at the end of the speed control, and the control input value U (k) (that is, the hydraulic pressure) is set to a very small value, so that the control delay at the time of resuming the phase control is effectively suppressed. Is done. Further, since the target drive voltage is compensated according to the resistivity of the linear solenoid 31, the linear solenoid 31 (that is, the VTC actuator 21) can be driven and controlled with higher accuracy.

  Although the description of the specific embodiment is finished as above, the present invention is not limited to the above embodiment and can be widely modified. For example, although the above embodiment is an application of the present invention to an in-line four-cylinder DOHC gasoline engine, it can naturally be applied to a diesel engine or the like. In the above embodiment, the intake camshaft is provided with the VTC actuator. However, the present invention may be applied to a cam phase variable internal combustion engine having the exhaust camshaft with the VTC actuator. Moreover, although the VTC actuator provided with OPA and CTA was employ | adopted in the said embodiment, you may employ | adopt the VTC actuator provided only with either one of OPA and CTA. In addition, the operating angle of the VTC actuator, the specific configuration of the engine and the variable valve operating device, and the like can be changed as appropriate without departing from the gist of the present invention.

4 intake camshaft 10 crankshaft 18 intake-side cam angle sensor 19 accelerator pedal sensor (driving operation state detection means)
20 ECON switch (operation mode switching means)
21 VTC actuator 22 Housing (first rotating member)
23 Rotor (second rotating member)
29 Spool valve (cam phase switching means)
31 Linear solenoid 61 1st OPA
62 1st OPA
63 CTA
70 Engine ECU
72 High-order command section 73 Cam phase change speed estimation section 74 Phase control section (phase control means)
75 Speed controller (speed control means)
76 Holding mode control unit (holding control means)
77 Holding input value learning unit (holding control amount learning means)
78 Control selection section (control selection means)
79 Resistivity compensation section (Resistivity compensation means)
E engine (cam phase variable internal combustion engine)

Claims (15)

A cam phase variable internal combustion engine in which the cam phase is variably controlled within a predetermined angle range,
A first rotating member that rotates in synchronization with the crankshaft;
A second rotating member that rotates integrally with the camshaft and is connected to the first rotating member so as to be relatively rotatable;
The cam phase is maintained at the advance angle and the retard angle by switching the hydraulic fluid circuit connected between the advance angle side oil chamber and the retard angle side oil chamber formed between the first rotation member and the second rotation member. Cam phase switching means for shifting between
Driving operation state detection means for detecting the driving operation state by the driver;
Engine operating state detecting means for detecting the engine operating state;
A speed control means for setting a target angular velocity from at least one of the driving operation state detection result and the engine operating state detection result and controlling the cam phase change speed based on the target angular velocity;
A phase control means for setting a target cam phase from at least one of the previous operation operation state detection result and the engine operation state detection result, and controlling the cam phase based on the target cam phase;
Control selection means for selecting either the speed control or the phase control based on at least one of the detection result of the driving operation state detection means and the detection result of the engine operation state detection means;
Speed control end determination means for determining the end of the speed control;
A holding control means for holding and controlling the cam phase at the end of the speed control in the direction of the speed control with a predetermined urging force when the speed control end judging means determines that the speed control has ended. A variable cam phase internal combustion engine. In the phase control, comprising a holding control amount learning means for sequentially learning a holding control amount for holding the cam phase,
2. The cam phase variable type according to claim 1, wherein the holding control unit sets the urging force by adding an additional control amount in the speed control direction to the holding control amount. 3. Internal combustion engine.   When the speed control end determination means determines that the speed control has ended, the holding control means controls the holding control means with a predetermined gradual decrease amount from the control amount at the time of speed control end to the control amount that gives the urging force. 3. The variable cam phase internal combustion engine according to claim 2, wherein the amount is gradually decreased.   4. The variable cam phase internal combustion engine according to claim 1, wherein the control selection unit selects the speed control unit during sudden acceleration or sudden deceleration. 5.   The control selection means performs the selection based on at least one of an engine rotational speed, an engine load, and an actual cam phase, and a required torque change speed. The cam phase variable internal combustion engine described in the paragraph.   The cam phase variable internal combustion engine according to any one of claims 1 to 5, wherein the control selection means selects the speed control means when the increase speed of the engine load is high. .   The cam according to any one of claims 1 to 6, wherein the control selection unit selects the speed control unit when a difference between a target cam phase and an actual cam phase is large. Variable phase internal combustion engine.   The control selection means selects the phase control means when the actual cam phase is in the vicinity of abutment and the change speed of the actual cam phase is lower than a predetermined value. The cam phase variable internal combustion engine according to claim 7. The speed control means performs feedback control including an integral term;
The cam phase according to any one of claims 1 to 8, wherein the speed control means stops the integral term when the phase control means is selected by the control selection means. Variable internal combustion engine.   The speed control means sets a speed target value based on at least one of an engine rotational speed, an engine load, and an actual cam phase, and a required torque change speed. A cam phase variable internal combustion engine according to claim 1.   The speed control means calculates a required air amount change speed based on at least one of the engine rotational speed, the engine load and the actual cam phase, and a required torque change speed, and the speed target based on the required air amount change speed. The cam phase variable internal combustion engine according to claim 10, wherein a value is set. The phase control means performs feedback control including an integral term;
The cam phase according to any one of claims 1 to 11, wherein the phase control means stops the integral term when the speed control means is selected by the control selection means. Variable internal combustion engine.   The cam phase variable internal combustion engine according to any one of claims 1 to 12, wherein the phase control means sets a phase target value based on an engine speed and a required torque. . One of driving modes including a fuel efficiency priority mode is provided with a driving mode switching means selected by the driver,
The cam phase according to any one of claims 1 to 13, wherein when the fuel efficiency priority mode is selected by a driver, a threshold value for switching from the phase control to the speed control is increased. Variable internal combustion engine. The cam phase switching means is driven by a linear solenoid;
The variable cam phase internal combustion engine according to any one of claims 1 to 14, further comprising resistivity compensation means for compensating for a change in resistivity of the linear solenoid.

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