JP2011236761A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine which effectively suppresses the occurrence of overshoot, hunting or the like, and quickly converges and matches an actual amount of an advance angle of valve timing to the target amount of the advance angle when performing the PID feedback control of the advance/delay angle control of the valve timing.SOLUTION: The amount of energization to a variable valve timing mechanism 60 corresponding to the amount of the advance angle is subjected to the PID feedback control so as to converge and match the actual amount of the advance angle to the target amount of the advance angle to be set based on the operating condition of an engine. During that time, the calculation of the initial value of the part D and the reduction from the initial value (the peak value) are performed based on the engine speed and the engine oil temperature.

Description

  The present invention relates to an internal combustion engine (hereinafter, referred to as a variable valve timing mechanism) having a variable valve timing mechanism capable of changing the opening / closing timing of an intake valve and / or an exhaust valve (hereinafter sometimes simply referred to as a valve timing or a phase) according to an operating state. In particular, it has a hydraulic variable valve timing mechanism for advancing and retarding the valve timing by hydraulic pressure supplied from an oil pump driven by the engine (crankshaft). The present invention relates to a control device for an internal combustion engine.

  Currently, automobile fuel efficiency and exhaust gas regulations are becoming stronger against the background of environmental problems such as global warming and air pollution. In order to comply with this regulation, recent internal combustion engines are equipped with a variable valve timing mechanism as standard. This variable valve timing mechanism allows the intake valve and / or exhaust valve opening / closing timing (phase as viewed in crank angle) to be arbitrarily changed (advanced / retarded), and is optimal for the operating state of the engine. It is intended to improve fuel economy, exhaust, output, driving performance, etc. by controlling the timing.

  As this variable valve timing mechanism, there are an electric type using a motor as a drive source and a hydraulic type using a discharge pressure of an oil pump driven and rotated by an engine crankshaft as a drive source. The hydraulic variable valve timing mechanism is applied to many in-vehicle internal combustion engines because the introduction cost is low although there is a problem that the responsiveness deteriorates when the discharge pressure of the oil pump is low or the water temperature is low.

  However, since it is hydraulic, the hydraulic pressure supplied to the variable valve timing mechanism is affected by its temperature (oil temperature) and engine speed. In consideration of this, in the control device described in Patent Document 1 below, it is sometimes compensated that the capability of the oil pump varies depending on the engine speed.

Patent No. 3776463

  However, in the control device described in Patent Document 1, it is described that the valve timing advance / retard angle control is performed by PID feedback control, and the respective P, I, and D minutes are set by the engine speed. However, the specific setting method is not clearly shown. Therefore, in the PID feedback control, the follow-up delay of the actual advance amount with respect to the target advance amount, overshoot, hunting, etc. can be sufficiently reduced. It can not be said.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to effectively suppress the occurrence of overshoot, hunting and the like when performing valve timing advance / retard control by PID feedback control. Another object of the present invention is to provide a control device for an internal combustion engine that can quickly converge and match an actual advance angle amount with a target advance angle amount and improve responsiveness and control accuracy.

  In order to achieve the above object, an internal combustion engine control apparatus according to the present invention controls a hydraulic variable valve timing mechanism that uses a discharge pressure of an oil pump that is rotationally driven by a crankshaft as a drive source. Includes a valve timing control means for setting a target advance amount for opening / closing timing of the intake valve and / or the exhaust valve and performing PID feedback control so that the actual advance amount converges and matches the target advance amount. The valve timing control means includes a difference calculation means for calculating a difference between the target advance angle amount and a current actual advance angle amount, and the D minutes based on the difference, the engine speed, and the engine oil temperature. It has a means for calculating an initial value, and a means for reducing the D component from the initial value based on the engine speed and the engine oil temperature.

  In the control apparatus for an internal combustion engine according to the present invention, a change in operating hydraulic pressure caused by a change in engine speed and a change in friction (frictional force of a sliding portion) caused by a change in engine oil temperature are supplied to a variable valve timing mechanism. Therefore, the occurrence of overshoot, hunting, etc. can be effectively suppressed, and the actual advance amount can be quickly converged and matched with the target advance amount. The responsiveness, control accuracy, etc. can be significantly improved as compared with the conventional one.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows one Embodiment of the control apparatus which concerns on this invention with an example of the vehicle-mounted internal combustion engine provided with the variable valve timing mechanism with which it was applied. The perspective view which shows the structure around the variable valve timing mechanism shown by FIG. The schematic sectional drawing which shows the hydraulic actuator and oil control valve which comprise the principal part of the variable valve timing mechanism shown by FIG. The figure which is provided for operation | movement description of the oil control valve shown by FIG. Schematic which shows the structure around ECU shown by FIG. The functional block diagram which shows the outline | summary of the various control which ECU performs. The figure used for description of phase control of the intake valve by the variable valve timing mechanism. (A) is a block diagram showing a configuration example of the valve timing control means, (B) is a block diagram showing a detailed configuration example of a control duty calculation block 805 in (A). FIG. 9 is a block diagram illustrating a detailed configuration example of a D-minute calculation block 824 in FIG. The block diagram which shows the detailed structural example of the D value peak value calculation block 901 in FIG. The block diagram which shows the structural example of the reduction process part in the D part reduction process block 902 in FIG. 4 is a time chart showing changes in a target advance amount, an actual advance amount, and a D minute when PID feedback control is performed so that the actual advance amount converges and matches the target advance amount. The figure which expands and shows a part of FIG. The flowchart which shows the outline | summary of the various control which ECU respond | corresponds to the functional block diagram shown by FIG. The flowchart which shows an example of the process sequence at the time of calculating | requiring control duty corresponding to the block diagram shown to FIG. 8 (A). The flowchart which shows an example of the process sequence at the time of calculating control duty (P minutes, I minutes, and D minutes) corresponding to the block diagram shown by FIG. 8 (B). The flowchart which shows an example of the process sequence at the time of calculating D minute peak value corresponding to the block diagram shown by FIG. The flowchart which shows an example of the process sequence at the time of calculating and outputting D part corresponding to the block diagram shown by FIG. The flowchart which shows an example of the process sequence at the time of carrying out reduction calculation of D part corresponding to the block diagram shown by FIG.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment (example) of a control device according to the present invention together with an example of an in-vehicle internal combustion engine provided with a variable valve timing mechanism to which the control device is applied.

  In FIG. 1, an internal combustion engine 10 to which the control device 1 of the present embodiment is applied has, for example, a spark having four cylinders # 1, # 2, # 3, and # 4 (represented by # 1 in the figure). An ignition-type multi-cylinder engine, which is slidably fitted into each cylinder # 1, # 2, # 3, and # 4 of the cylinder 11 including a cylinder head 11a and a cylinder block 11b. A piston 15, and the piston 15 is connected to the crankshaft 13 via a connecting rod 14. Above the piston 15, a combustion working chamber 17 having a combustion chamber (ceiling or roof) having a predetermined shape is defined, and the combustion working chamber 17 of each cylinder # 1, # 2, # 3, # 4 is ignited. A spark plug 35 to which a high-voltage ignition signal is supplied from the coil 34 is provided.

  The air used for the combustion of fuel is supplied from the air cleaner 19 to a tubular passage portion (throttle body or the like) in which an air flow sensor 53 such as a hot wire type or an electric throttle valve 25 is disposed, a collector 27, an intake manifold (various) Each cylinder # 1, # 2, # 3, # 4 through an intake valve 21 disposed at a downstream end (end portion of the intake port 29) through an intake passage 20 including a pipe) 28, an intake port 29 and the like. Are sucked into the combustion working chamber 17. A fuel injection valve 30 for injecting fuel toward the intake port 29 is provided for each cylinder (# 1, # 2, # 3, # 4) in the downstream portion of the intake passage 20 (intake manifold 28). The intake manifold 28 is also provided with an intake sensor 59 (which serves as both an intake pressure sensor and an intake temperature sensor) for detecting intake pressure (internal pressure downstream of the throttle valve 25 in the intake passage 20) and intake air temperature. Be present.

  The air-fuel mixture of the air sucked into the combustion working chamber 17 and the fuel injected from the fuel injection valve 30 is burned by spark ignition by the spark plug 35, and the combustion waste gas (exhaust gas) is discharged from the combustion working chamber 17. Via the exhaust valve 22, the exhaust port 41, the exhaust manifold 42, the exhaust pipe 45 provided with an exhaust purification catalyst (for example, a three-way catalyst) 50, etc. are exhausted to the outside (in the atmosphere). . An air-fuel ratio sensor (oxygen concentration sensor) 57 is disposed upstream of the catalyst 50 in the exhaust passage 40.

  Further, the fuel injection valve 30 provided for each cylinder (# 1, # 2, # 3, # 4) is supplied with fuel (gasoline etc.) in a fuel tank provided with a fuel pump, a fuel pressure regulator, and the like. The fuel injection valve 30 is supplied from an ECU (engine control unit) 100, which will be described later, and has a pulse width corresponding to the operating state at that time (corresponding to the valve opening time). The valve is driven to open by a drive pulse signal having the following, and an amount of fuel corresponding to the valve opening time is injected toward the intake port 29.

  A crank pulley 63 is attached and fixed to one end of the crankshaft 13, and an intake cam pulley 61 for phase change is externally fitted to one end of the intake camshaft 23 for opening and closing the intake valve 21, and the exhaust valve 22 is opened and closed. A normal exhaust cam pulley 62 is fitted and fixed to one end of the exhaust cam shaft 24 for this purpose. Teeth are provided on the outer peripheral portions of the pulleys 61, 62, 63, the timing belt 65 is wound around the pulleys 61, 62, 63, and the rotation of the crankshaft 13 is transmitted to the intake camshaft 23. It is transmitted via an intake cam pulley 61 and a hydraulic actuator 70 (described later) incorporated therein, and is transmitted to an exhaust cam shaft 24 via an exhaust cam pulley 62. The rotation speed ratio of the crank cam pulley 63 to the intake cam pulley 61 and the exhaust cam pulley 62 is 1: 2.

  Further, the engine 10 is provided with an oil pump 66 so as to be driven to rotate by the crankshaft 13. The hydraulic oil discharged from the oil pump 66 lubricates the engine 10, and will be described later. The hydraulic pressure is supplied to the hydraulic variable valve timing mechanism 60.

  In addition to the above configuration, the internal combustion engine 10 of the present embodiment includes a hydraulic variable valve timing that can change the opening / closing timing (phase) of the intake valve 21 in accordance with the operating state of the internal combustion engine 10 and the engine-equipped vehicle. A mechanism 60 is equipped.

Hereinafter, the configuration of the variable valve timing mechanism 60 of the present embodiment will be described with reference to FIGS.
The variable valve timing mechanism 60 of this embodiment advances the opening / closing timing (phase) of the intake valve 21 by rotating the intake cam shaft 23 relative to the intake cam pulley 61 (this crank angle becomes the reference crank angle). In order to retard the angle, a hydraulic actuator 70 built in the intake cam pulley 61 and an oil control valve 80 disposed between the hydraulic actuator 70 and the oil pump 66 are provided.

  The hydraulic actuator 70 includes a rotor housing 72 provided integrally with the intake cam pulley 61, and a vane rotor (impeller) 73 that is externally fixed to the intake cam shaft 23 (for example, by spline coupling). The rotor housing 72 includes an annular base portion 72b and four partition plate portions 72a protruding radially inward from the base portion 72b. The vane rotor 73 includes a disk-shaped portion 73b and the disk-shaped portion. And four vane portions 73a projecting radially outward from 73b. The four partition plate portions 72 a of the rotor housing 72 are arranged at equiangular (90 degrees) intervals, and the seal material 74 is pressed against the outer peripheral surface of the disc-shaped portion 73 b of the vane rotor 73 at the tip portions thereof. Is installed. The four vane portions 73a of the vane rotor 73 are arranged at equiangular (90 degrees) intervals so as to be positioned between the adjacent partition plate portions 72a and 72a, respectively. A sealing material 74 is mounted so as to be in pressure contact with the inner peripheral surface of the base portion 72b.

  With such a configuration, four fan-shaped advance chambers 75 and retard chambers 76 having variable volumes are alternately defined between the four partition plate portions 72a and the four vane portions 73a. Is done. The four advance angle chambers 75 and the retard angle chamber 76 are supplied with hydraulic oil (working hydraulic pressure) from the oil pump 66 through the oil passage 67 → the oil control valve 80 → the hydraulic passage 68 or 69.

  On the other hand, the oil control valve 80 includes a valve housing 85 having a hydraulic pressure supply port 90, an advance port 91, a retard port 92, and drain ports 88 and 89, a solenoid 83, a plunger 84, a spool 86, and a compression coil spring 87. In the state where the solenoid 83 is not energized and energized, as shown in FIG. 3, the spool 86 is pushed by the compression coil spring 87 and located at the right end. When the solenoid 83 is energized and energized, the plunger 84 pushes the spool 86 leftward, so that the urging force of the compression coil spring 87 is overcome and the spool 86 moves leftward. The amount of movement of the spool 86 in the left direction increases in proportion to the energization amount (supply current value) to the solenoid 83.

  The hydraulic pressure supply port 90 of the valve housing 85 is in an oil passage 67 connected to the discharge port of the oil pump 66, the advance port 91 is in a phase advance hydraulic passage 68, and the retard port 92 is in a phase retard hydraulic passage 69. The drain ports 88 and 89 are connected to drain passages (not shown).

  As shown in FIG. 4A, when the spool 86 is located at the right end, the hydraulic pressure supply port 90 and the retard port 92 communicate with each other, and at the same time, the drain port 88 and the advance port 91 And communicate. Therefore, the hydraulic oil discharged from the oil pump 66 is guided to the retard chamber 76, and the hydraulic oil in the advance chamber 75 is discharged to the oil pan through the drain passage. Therefore, the vane rotor 73 and the intake camshaft 23 integrated therewith rotate relative to the intake cam pulley 61 in the opposite direction, and the phase of the crank corresponds to the amount of hydraulic oil introduced into the retard chamber 76 (hydraulic pressure). As shown in FIG. 7, the opening / closing timing (phase) of the intake valve 21 is retarded, and the intake valve 21 is opened later.

  As shown in FIG. 4B, when the spool 86 is located at the center (intermediate between the right and left row ends), the hydraulic pressure supply port 90, the advance port 91, the retard port 92, All of the drain ports 88, 89 are closed. For this reason, there is no flow of hydraulic oil, and the vane rotor 73 does not change the phase with respect to the intake cam pulley 61.

  As shown in FIG. 4C, when the spool 86 is located at the left end, the hydraulic pressure supply port 90 and the advance port 91 communicate with each other, and at the same time, the drain port 89 and the retard port 92 Communicate. Therefore, the hydraulic oil discharged from the oil pump 66 is guided to the advance chamber 75, and the hydraulic oil in the retard chamber 76 is discharged to the oil pan through the drain passage. Therefore, the vane rotor 73 and the intake cam shaft 23 integrated with the vane rotor 73 rotate relative to the intake cam pulley 61 in the same direction, and the crank angle corresponding to the amount of hydraulic oil introduced into the advance chamber 75 (hydraulic hydraulic pressure). As shown in FIG. 7, the opening / closing timing (phase) of the intake valve 21 is advanced, and the intake valve 21 is opened earlier.

  On the other hand, various controls of the engine 10, that is, fuel injection control by the fuel injection valve 30, ignition timing control by the spark plug 35, and opening / closing timing (phase) of the intake valve 21 by the hydraulic variable valve timing mechanism 60. In order to perform control and the like, an ECU (Engine Control Unit) 100 incorporating a microcomputer is provided.

  The ECU 100 is basically well known as shown in FIG. 5, and an input / output circuit (I / O_LSI) including an MPU 201, an EP-ROM 202, a RAM 202, and an A / D converter. 205, and a driver (not shown). In the control unit 100, signals from various sensors as described later are input as inputs, predetermined calculation processing is executed, various control signals calculated as the calculation results are generated, and fuel injection as an actuator is performed. A predetermined control signal is supplied to the valve 30, the ignition coil 34, the oil control valve 80, etc. at a predetermined timing to execute fuel injection control, ignition timing control, intake valve timing control, and the like.

  The ECU 100 receives, as an input signal, a signal corresponding to the intake air amount detected by the air flow sensor 53, a signal corresponding to the opening (throttle opening) of the throttle valve 25 detected by the throttle sensor 54, A signal (crank angle sensor 55) representing the rotation (engine speed) and phase (crank angle) of the crankshaft 13 (the toothed disk 55a provided on the crankshaft 13) obtained from the attached crank angle sensor (rotation speed sensor) 55. From, for example, a pulse signal is output at every rotation angle of 1 degree), the intake camshaft 23 obtained from the cam angle sensor 56 attached to the intake camshaft 23 (the toothed disk 56a provided on the intake camshaft 23). A signal representing the rotation and phase (a pulse signal is output from the cam angle sensor 56, for example, every 180 ° C. Cylinder determination and the like are performed based on the pulse signal from the angle sensor 55), and the exhaust air-fuel ratio (oxygen concentration) from the air-fuel ratio sensor 57 disposed upstream of the three-way catalyst 50 in the exhaust passage 40 is determined. A signal corresponding to the engine cooling water temperature detected by the water temperature sensor 58 provided in the cylinder block 12, and an intake pressure and an intake temperature detected by the intake sensor 59 provided in the intake passage 20. A signal, a signal from an ignition key switch (not shown) that is a main switch for operating and stopping the internal combustion engine 10 are supplied. Further, information such as the shift position of the transmission, such as the P range, N range, and D range, and the vehicle speed is provided from the vehicle (integrated) control unit (TCU) 200 by inter-unit communication.

  The engine water temperature detected by the water temperature sensor 58 is also used when estimating the engine oil temperature used in the control of the variable valve timing mechanism 60 described later.

  The ECU 100 recognizes the operating state of the engine 10 based on the various input signals, and calculates main operation amounts of the engine 10 such as fuel injection control, ignition timing control, and intake valve timing control based on the operating state. To do.

  Here, the control of the variable valve timing mechanism 60 performed by the ECU 100, in other words, the control of the oil control valve 80 (solenoid 83) will be described.

  The phase of the intake camshaft 23 with respect to the crankshaft 13 (actual advance angle amount from the reference crank angle) is outputted from the cam angle sensor 56 and a signal representing the rotational position of the crankshaft 13 outputted from the crank angle sensor 55. It is calculated by the ECU 100 using a signal representing the rotational position of the intake camshaft 23. Note that the amount of advance is negative when retarded from the reference crank angle.

  The control unit 100 controls the variable valve timing mechanism 60 (solenoid) so that the target cam phase (target advance angle amount) calculated based on the operating state of the engine 10 and the actual cam phase (actual advance angle amount) are equal. 83) PID feedback control is performed on the energization amount. Here, the energization amount to the solenoid 83 is controlled by so-called duty control in which a ratio (duty ratio) of applying voltage to the solenoid 83 within a unit time is changed. In this case, when the control duty (%) is increased to a predetermined value or more, the energization amount (supply current value) to the solenoid 83 increases, the spool 86 moves to the left, and the actual cam phase is displaced in the advance direction (advance angle). The amount increases). If the control duty is further increased, the left row end position is taken as shown in FIG. When the control duty is reduced to a predetermined value or less, the energization amount (supply current value) to the solenoid 83 decreases, the spool 86 moves to the right, and the actual cam phase is displaced in the retard direction. If the control duty is further reduced, the right row end position is taken as shown in FIG. When the control duty is set to an intermediate value, the energization amount (supply current value) to the solenoid 83 also becomes an intermediate value, and the spool 86 takes an intermediate position as shown in FIG. ) Does not change.

  The control unit 100 that controls the variable valve timing mechanism 60 as described above includes an engine speed calculation means 101 that calculates the engine speed and the crank angular speed, and an intake air amount, as shown in functional blocks in FIG. Calculation means 102, basic injection amount calculation means 103, basic injection amount correction coefficient calculation means 104, basic ignition timing calculation means 105, air-fuel ratio feedback control coefficient calculation means 108, target air-fuel ratio setting means 109, basic injection amount correction means 110, Ignition timing correction means 112 and valve timing control means 130 are provided.

  The engine speed calculation means 101 counts the number of times the pulse signal from the crank angle sensor 55 changes per unit time (for example, the rise or fall of the pulse) (the number of arrivals) and performs a predetermined arithmetic process to perform the unit. Calculate the engine speed per hour.

  The intake air amount calculation means 102 converts the signal from the air flow sensor 53 into a voltage-flow rate to determine the amount of air sucked into the engine, and with respect to the obtained air amount, the air amount measurement time point and the combustion working chamber 17 are supplied. Correct the delay at the point of inflow. The correction of the delay is a first-order delay compensation of the arrival time of the airflow, but the details are omitted.

  The basic injection amount calculation means 103 calculates the basic injection amount and the engine load based on the engine speed and the intake air amount calculated by the engine speed calculation means 101 and the intake air amount calculation means 102.

  The basic injection amount correction coefficient calculation unit 104 calculates a correction coefficient for the basic injection amount calculated by the basic injection amount calculation unit 103.

  The basic ignition timing calculation means 105 sets the optimal ignition timing in each region of the engine based on the above-described engine speed and engine load by map search or the like.

  The air-fuel ratio feedback control coefficient calculation means 108 calculates an air-fuel ratio feedback control coefficient by PID control based on the signal from the air-fuel ratio sensor 57 so that the air-fuel mixture used for combustion is maintained at the target air-fuel ratio. In this example, the air-fuel ratio sensor 57 outputs a signal proportional to the exhaust air-fuel ratio, but is the exhaust gas on the rich side relative to the stoichiometric air-fuel ratio? Even if it is on the lean side, a signal that outputs a binary (High, Low) level signal may be used.

  The target air-fuel ratio setting means 109 determines the optimum target air-fuel ratio in each region of the engine by reading a map or the like based on the engine speed and the engine load described above. The target air-fuel ratio determined here is used for the air-fuel ratio feedback control of the air-fuel ratio feedback control coefficient calculation means 108 described above.

  The basic injection amount correction means 110 corrects the above-described basic injection amount by a basic injection amount correction coefficient, an acceleration / deceleration fuel correction amount, an air-fuel ratio feedback control coefficient, and the like.

  The ignition timing correction means 112 corrects the ignition timing set by the basic ignition timing calculation means 105 by the engine coolant temperature or the like.

  The valve timing control means 130 performs PID feedback control of the energization amount (advance amount) to the solenoid 83 in order to advance or retard the opening / closing timing of the intake valve 21 from the reference crank angle according to the engine operating state. Basically, it is set according to the engine operating state (for example, it is set by reading out the optimum valve timing in each region of the engine by map search etc. based on the engine speed, engine load, etc.) A control duty corresponding to the energization amount to the oil control valve 80 (solenoid 83) is set so that the actual advance amount obtained from the crank angle sensor signal and the cam angle sensor signal converges with the target advance amount.

  FIG. 8A shows a configuration example of the valve timing control means 130, and is a block diagram showing an example of a processing procedure for obtaining a control duty corresponding to an energization amount to the oil control valve 80.

  In FIG. 8A, in block 801, the current actual advance amount of the intake valve 21 is obtained from the crank angle sensor signal and the cam angle sensor signal. In block 802, the correction amount of the mechanical dead zone is learned from the relationship between the current actual advance amount and the current control duty, or the learned amount at that time is reflected. More specifically, it stores how much the control duty changes the advance amount, and stores it as a mechanical dead zone. In block 807, an advance speed correction with respect to the control duty is applied to the corrected amount of the mechanical dead zone. Specifically, since the mechanical dead zone is corrected in block 802, the advance speed per unit control duty is learned, and a duty value that can compensate for the minimum required advance speed is stored. In block 803, a target advance amount is obtained based on the engine speed, the engine water temperature, the engine intake air temperature, and the engine load. As a technique, for example, a basic target advance amount is retrieved from a map of engine speed and engine load, and is corrected by the engine water temperature and the engine intake air temperature. However, details are omitted. Block 804 determines the difference between the current actual advance amount and the target advance amount. A block 805 calculates a control duty based on the difference, the engine speed, and the engine water temperature (engine oil temperature) so that the actual advance amount becomes the target advance amount. The detailed configuration of the block 805 will be described later with reference to FIG. In block 808, the dead zone correction amount and forward angular velocity correction obtained in block 807 are added to the control duty obtained in block 805 for correction. Finally, the battery voltage is corrected in block 809 and the temperature is corrected in block 810, and then output as a control duty. The temperature correction of the block 810 corrects the temperature characteristic of the oil control valve 80. In this example, the temperature is represented by the engine water temperature, but the actual temperature of the oil control valve 80 is detected and corrected. Also good.

  FIG. 8B shows a detailed configuration example of the control duty calculation block 805 in FIG. In block 821, the engine oil temperature is estimated from the engine water temperature. As a means for estimation, there is a table search for the oil temperature predicted from the water temperature, but the details are omitted. As another method, a method of estimating the oil temperature by integrating the elapsed time from the starting time or the intake air amount of the engine from the starting time may be used. In blocks 822, 823, and 824, control duty I, P, and D are respectively determined based on the difference between the target advance amount and the actual advance amount, the engine speed, and the engine oil temperature. . The calculated I, P, and D minutes are added at block 825 and output as a control duty.

  FIG. 9 shows a detailed configuration example of the D-minute calculation block 824 in FIG. In this example, in block 901, a peak value (initial value) for D is calculated based on the difference between the target advance angle amount and the actual advance angle amount, the engine speed, and the engine oil temperature (refer to FIG. 10 for details). Will be described later). In block 902, the D portion is reduced based on the D portion peak value, the engine oil temperature, and the engine speed (details will be described later with reference to FIG. 11).

  In block 903, the absolute value of the difference between the target advance angle amount and the actual advance angle amount is calculated and sent to the comparison blocks 905 and 907. In block 904, a difference threshold value Ea for the D minute set is obtained by table search based on the engine speed. The difference threshold value Ea obtained here is compared with the absolute value of the difference in the comparison block 905. If the difference absolute value is greater than or equal to the difference threshold value Ea, the D block setting command is sent from the comparison block 905 to the D block reduction processing block 902. Is emitted. When the D minute set command is input, the D minute reduction processing block 902 outputs the D minute peak value calculated by the D minute peak value calculation block 901 as the D minute initial value. As a result, in addition to the P and I minutes, the D portion is added (set) to the control duty. Note that the initial value of D is a peak value, and after that, it is reduced by reduction processing.

  On the other hand, in block 906, a difference threshold value Eb for D minute reset is obtained by table search based on the engine speed. The difference threshold value Eb obtained here is compared with the absolute value of the difference in the comparison block 907. If the difference absolute value is equal to or less than the difference threshold value Eb, the D block reset command is sent from the comparison block 907 to the D component reduction processing block 902. Is emitted. In the D-minute reduction processing block 902, when the D-minute reset command is input, all the calculation contents are reset and the D-minute is cleared to zero. As a result, D is not added (set) to the control duty.

  The set difference threshold value Ea and the reset difference threshold value Eb are set to a larger value as the engine speed is higher. As a matter of course, the set difference threshold value Ea is higher than the reset difference threshold value Eb. (The details will be described later with reference to FIGS. 12 and 13).

  FIG. 10 shows a detailed configuration example of the D-minute peak value calculation block 901 in FIG. In this example, the basic amount of the peak value for D is obtained in block 1001 based on the difference between the target advance amount and the actual advance amount. A block 1002 calculates a rotation speed correction coefficient based on the engine speed, a block 1003 calculates an oil temperature correction coefficient based on the engine oil temperature by table search, and a multiplier 1004 multiplies the basic quantity by the correction coefficient. Output as D minute peak value. Here, the rotational speed correction coefficient and the oil temperature correction coefficient with respect to the basic amount of the D-minute peak value are set to values of 1 or less. In this case, the higher the engine speed and the higher the engine oil temperature. Since the hydraulic pressure supplied to the variable valve timing mechanism 60 becomes higher, the rotational speed correction coefficient and the oil temperature correction coefficient are set to smaller values as the engine rotational speed is higher and the engine oil temperature is higher. The

FIG. 11 shows a configuration example of the reduction processing portion in the D-division reduction processing block 902 in FIG. In this example, the basic value of the weighted average weight is searched in a table in block 1101 based on the engine speed. In block 1102, the weighted oil temperature correction value is retrieved based on the engine oil temperature, and the multiplier 1103 corrects the basic value with the oil temperature correction value. A block 1104 is a weighted average block, and the D portion is reduced toward the zero with the corrected weighted average weight. The weighted average is performed by the following formula.
D minute = D minute past value × (1-weighted average weight)
The initial value of the D minute past value is the D minute peak value.

  In this example, the D reduction processing is performed by a weighted average, but a method of calculating and reducing the reduction amount per unit time may be used.

  12A and 12B show the target advance angle when the control duty is calculated in the manner as described above and PID feedback control is performed so that the actual advance amount converges and matches the target advance amount. It is a time chart which shows change of quantity, actual advance amount, and D minute. In FIGS. 12A and 12B, the actual advance amount and the D portion are indicated by a solid line, and the target advance amount is indicated by a broken line. In the figure, the target advance angle amount and the actual advance angle amount are equal until time t1, but the engine operation state changes and the target advance amount increases linearly from time t1 to time t7 as shown in the figure. In this case, the actual advance amount is slightly delayed from the change in the target advance amount by the PID feedback control (after the difference between the target advance amount and the actual advance amount becomes a predetermined amount or more) in a stepped manner (that The step changes in a stepwise manner), crosses the target advance amount at time points t2, t3, t4, t5, and t6, and catches up with the target advance amount at time point t7. In this case, the D component takes a positive value when the actual advance amount is smaller than the target advance amount (a D component is added to the control duty), and is negative when the actual advance amount is greater than the target advance amount. A value is taken (D is subtracted from the control duty).

  More specifically, in FIG. 13 (A) and FIG. 13 (B) in which a part of FIG. 12 (from time t1 to around t4) is enlarged, taking the D portion between time t2 and t3 as an example, the actual advance angle At a time t01 when the difference (absolute value) between the target advance amount and the actual advance amount becomes equal to or larger than the above-described difference threshold Ea for the D minute set, a little later than the time point t2 when the amount exceeds the target advance amount. The peak value for D calculated as described above is added (set) to the control duty as an initial value (here, it is subtracted because D is a negative value). Thereafter, the D portion is reduced as described above and reduced while drawing a quadratic curve, and then the difference (absolute value) between the target advance amount and the actual advance amount is used for the D portion reset described above. At the time t02 when the difference threshold value Eb becomes equal to or less than D, the D portion is returned to 0 as described above, and the D portion is not added to the control duty.

  FIG. 14 is a flowchart showing an outline of various controls executed by the ECU, corresponding to the functional block diagram shown in FIG. 6 described above.

  Here, the engine speed is calculated in step 1401, and the outputs of the air flow sensor, the water temperature sensor, etc. are read in step 1402. In step 1403, the output of the air flow sensor is subjected to voltage flow rate conversion and response delay compensation to obtain the engine intake air amount. In step 1404, the basic injection amount and the engine load are calculated from the engine speed and the intake air amount. In step 1405, a map search is performed for the basic injection amount correction coefficient from the engine speed and the engine load. In step 1406, the output of the oxygen concentration sensor is read. In step 1407, a target air-fuel ratio corresponding to the engine operating state is set. In step 1408, an air-fuel ratio feedback control coefficient is calculated so as to realize the target air-fuel ratio. In step 1409, the calculated basic injection amount is corrected with the basic fuel correction coefficient and the air-fuel ratio feedback control coefficient. In step 1410, an appropriate basic ignition timing according to the engine operating state is calculated. In step 1411, a basic ignition timing correction coefficient based on engine water temperature or the like is calculated. In step 1412, the basic ignition timing is corrected using a correction coefficient for the basic ignition timing. In step 1413, a target advance amount is set by map search or the like based on the engine speed and the engine load. In step 1414, the control duty I is calculated. In step 1415, the control duty P is calculated. In step 1416, the control duty D is calculated. In step 1417, the final control duty is calculated for the I, P and D minutes.

  FIG. 15 is a flowchart showing an example of a processing procedure when the opening / closing timing (advance amount) of the intake valve 21 is subjected to PID feedback control, and corresponds to the block diagram for obtaining the control duty shown in FIG. is doing.

  In this example, in step 1501, the current actual advance amount is calculated from the crank angle sensor signal and the cam angle sensor signal. In step 1502, the mechanical dead zone is learned from the control duty and the actual advance amount, and the already learned value is reflected. In step 1503, the speed correction amount is learned from the control duty and the advance speed, and the already learned value is reflected. In step 1504, a target advance amount is calculated from the engine speed, engine water temperature, engine intake air temperature, engine load, and the like. In step 1505, a difference between the target advance amount and the current actual advance amount is calculated. In step 1506, the control duty is calculated from the difference, the engine speed, and the engine water temperature. In step 1507, speed correction is performed on the control duty. In step 1508, battery voltage correction and oil control valve temperature correction are applied to the control duty, and in step 1509, the control duty is output.

  FIG. 16 is a flowchart illustrating an example of a processing procedure when calculating the control duty (P, I, and D) corresponding to the above-described FIG. 8B.

  Here, in Step 1601, the difference between the target advance angle amount and the current actual advance angle amount is read. In step 1602, the oil temperature is estimated from the engine water temperature. In step 1603, I is calculated. In step 1604, P minutes are calculated. In step 1605, the feedback D is calculated. In step 1606, the feedback I, P and D components are added, and in step 1607, the control duty is output.

  FIG. 17 is a flowchart illustrating an example of a processing procedure for calculating the D-minute peak value corresponding to FIG. 10 described above.

  Here, in step 1701, the basic amount of the peak value for D is searched from the table using the difference between the actual advance amount and the target advance amount. In step 1702, a rotational speed correction coefficient is set by table search based on the engine rotational speed. In step 1703, an oil temperature correction coefficient is set by table search based on the engine oil temperature. In step 1704, the basic charge for the D-minute peak value is multiplied by the rotation speed correction coefficient and the oil temperature correction coefficient, and in step 1705, this is output as the D-minute peak value.

  FIG. 18 is a flowchart showing an example of a processing procedure when calculating and outputting the D component, corresponding to FIG. 9 described above.

  Here, in Step 1801, the difference between the target advance angle amount and the current actual advance angle amount, the engine speed, and the engine oil temperature are read, and a D-minute peak value is calculated based on these. In subsequent step 1802, based on the engine speed, a difference threshold value Ea for the D minute set is obtained by table search. In the subsequent step 1803, it is determined whether or not the difference between the target advance angle amount and the actual advance angle amount is equal to or greater than the difference threshold value Ea. If so, the process proceeds to step 1808 to output the D-minute peak value calculated in step 1801 as the D-minute initial value; otherwise, the process proceeds to step 1804.

  In step 1804, based on the engine speed, a difference threshold value Eb for D minute reset is obtained by table search. In the subsequent step 1805, it is determined whether or not the difference between the target advance angle amount and the actual advance angle amount is equal to or less than the difference threshold value Eb. If it is equal to or less, the process proceeds to step 1807 to perform reduction calculation for D, and in subsequent step 1808, the D reduction calculated is output. Otherwise, in step 1806, D is reset (cleared to 0). In step 1808, 0 is output as the calculated value for D.

  FIG. 19 is a flowchart corresponding to FIG. 11 described above, illustrating an example of a processing procedure when calculating the reduction of D.

  Here, it is determined in step 1901 whether or not there is a reset command for D minutes. If it is determined that there is, the D minute is cleared to 0 in step 1902, and if it is determined that there is no, the engine speed and the engine oil temperature are read in step 1903, and then weighted using the engine speed in step 1904. Search the table for average weights. In step 1905, a table search is performed for the oil temperature correction coefficient using the engine oil temperature, and the weighted average weight is corrected. In step 1906, the corrected weighted average weight is averaged to 0 for the D minute peak value and output as D minutes.

  As described above, in the control device 1 of the present embodiment, the advance amount is set so that the actual advance amount converges and matches the target advance amount set based on the engine operating state (engine speed, engine load, etc.). The variable valve timing mechanism 60 (the solenoid 83) corresponding to is controlled by PID feedback control. At that time, the initial value calculation for D and the reduction processing from the initial value (peak value) are performed in the engine rotation. Since the operation is performed based on the engine speed and the engine oil temperature, it is difficult to be affected by a change in operating hydraulic pressure caused by a change in engine speed, a change in friction caused by a change in engine oil temperature, and the like.

In addition, since the set (addition) and reset (0 clear) timings for D are set based on the difference, occurrence of overshoot, hunting, etc. can be effectively suppressed, and the target advance angle is set. It is possible to quickly converge and match the actual advance amount to the amount, and as a result, the responsiveness, the control accuracy, etc. can be remarkably improved as compared with the conventional one.
The present invention is not limited to the above-described embodiment, and can be similarly applied to, for example, a case where the opening / closing timing of the exhaust valve is variable instead of the intake valve or in addition to the intake valve. .

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 13 Crankshaft 21 Intake valve 22 Exhaust valve 23 Intake camshaft 24 Exhaust camshaft 55 Crank angle sensor 56 Cam angle sensor 60 Variable valve timing mechanism 61 Intake cam pulley 62 Exhaust cam pulley 63 Crank pulley 65 Timing belt 70 Hydraulic actuator 72 Rotor housing 73 Vane rotor 75 Advance chamber 76 Delay chamber 80 Oil control valve 100 ECU

Claims (4)

A control device for an internal combustion engine comprising a hydraulic variable valve timing mechanism that uses a discharge pressure of an oil pump that is rotationally driven by a crankshaft as a drive source,
A valve timing control means for setting a target advance amount for the opening / closing timing of the intake valve and / or the exhaust valve, and for performing PID feedback control so that the actual advance amount converges and matches the target advance amount;
The valve timing control means includes:
Difference calculation means for calculating a difference between the target advance amount and the current actual advance amount;
Means for calculating an initial value for D based on the difference, engine speed, and engine oil temperature;
Means for reducing the D component from the initial value based on the engine speed and the engine oil temperature;
A control apparatus for an internal combustion engine, comprising:   The valve timing control means sets the D minute set timing setting means for setting the timing for setting the D minute based on the difference, and sets the D minute reset for setting the timing for resetting the D minute based on the difference. The control device for an internal combustion engine according to claim 1, further comprising timing setting means.   The D minute set timing setting means sets the timing for setting the D minute at a time point when the difference becomes equal to or greater than a set threshold value determined based on the engine speed. Control device for internal combustion engine.   The D-minute reset timing setting means sets the timing for resetting the D-minute at a time when the difference becomes equal to or less than a reset threshold determined based on the engine speed. The control apparatus of the internal combustion engine described in 1.

Images