JP2000257454A - Valve timing controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control valve timing with an appropriate response speed by absorbing piece-to-piece variation of internal combustion engine, variable valve timing mechanism, and oil control valve. SOLUTION: According to the operating condition of an engine 1, open-close timing of an intake valve 17 is changed by a variable valve timing mechanism 60. A response speed of the variable valve timing mechanism 60 is controlled, based on a control duty ratio of an oil control valve 63. The control duty ratio is corrected by learning according to whether the response speed of the variable valve timing mechanism is faster or slower than the expected response speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for an internal combustion engine having a variable valve timing mechanism for changing the opening / closing timing of a valve provided in a cylinder of the internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine mounted on an automobile or the like, a variable valve timing mechanism is provided to increase or decrease the torque in accordance with the operating state (engine speed and load). (Valve timing) change control technology is known. In this type of technology, the oil supplied to the variable valve timing mechanism is controlled based on the control duty ratio of the oil control valve, so that the variable valve timing mechanism is operated at a response speed corresponding to the control duty ratio, and the valve timing is controlled. Control.

Here, when calculating the control duty ratio of the oil control valve, first, a target valve timing (hereinafter, referred to as a "target advance value") is calculated based on the engine operating state. A deviation between the angle value and the actual valve timing (hereinafter, referred to as “actual advance angle value”) is calculated. Then, based on this deviation, a basic control duty ratio (basic duty ratio) DUB is calculated. In addition to the calculation of the basic duty ratio DUB, the amount of change in valve timing based on the difference between the current actual advance value and the previously detected actual advance value (hereinafter, referred to as “advance value change amount”) As a result, the correction duty ratio DUD is calculated. And the oil control valve is
These basic duty ratio DUB and correction duty ratio D
The oil supplied to the variable valve timing mechanism is controlled by controlling the control duty ratio in combination with UD. Then, the variable valve timing mechanism operates at a response speed corresponding to the control duty ratio to control the valve timing.

[0004]

The actual operation of the variable valve timing mechanism with respect to the control duty ratio of the oil control valve thus calculated is as follows.
It has been confirmed by the inventor that the engine, the variable valve timing mechanism, the oil control valve, and the like differ depending on individual variations. Therefore, if excessive oil is supplied to, for example, the variable valve timing mechanism due to such individual variation, the variable valve timing mechanism operates at an excessive response speed. Conversely, if not enough oil is supplied to the variable valve timing mechanism, the mechanism will operate with a response delay. Then, the valve timing is controlled at an excessive response speed, or is controlled with a response delay.

An object of the present invention is to provide a valve timing control apparatus for an internal combustion engine that can control the valve timing at a suitable response speed by absorbing individual variations such as an internal combustion engine, a variable valve timing mechanism, and an oil control valve. Is to do.

[0006]

According to one aspect of the present invention, there is provided a variable valve timing mechanism for changing a valve timing, operating state detecting means for detecting an operating state of an internal combustion engine, Target valve timing calculation means for calculating a target value of the valve timing of the variable valve timing mechanism based on the detection result of the operating state detection means, and actual valve timing detection means for detecting the actual valve timing of the variable valve timing mechanism A valve timing change amount detecting means for detecting a change amount of the actual valve timing, and a basic drive control of the variable valve timing mechanism based on a calculation result of the target valve timing calculating means and a detection result of the actual valve timing detecting means. Basic drive control amount calculating means for calculating the amount, and the valve tie Correction drive control amount calculation means for calculating a correction drive control amount of the variable valve timing mechanism based on the detection result of the variable valve timing mechanism; and the variable valve timing mechanism based on the detection result of the valve timing change amount detection means. Response speed judging means for judging whether the response speed of the variable valve timing mechanism is faster or slower than the expected response speed, and a response speed of the variable valve timing mechanism based on the judgment result of the response speed judging device. When it is determined that the speed is also fast, the drive control amount based on the calculation results of the basic drive control amount calculation means and the correction drive control amount calculation means is learned and corrected so that the response speed becomes slow,
A drive control amount learning correction means for learning and correcting the drive control amount so as to increase the response speed when it is determined that the response speed of the variable valve timing mechanism is lower than an expected response speed; The gist of the invention is to provide a driving means for driving the variable valve timing mechanism with the drive control amount learned and corrected by the control amount learning correction means.

According to the above construction, when the response speed judging means judges that the response speed of the variable valve timing mechanism is faster than the expected response speed, the basic drive is performed so that the response speed becomes slower. The drive control amount based on the calculation results of the control amount calculation means and the correction drive control amount calculation means is learned and corrected. Similarly, when it is determined that the response speed of the variable valve timing mechanism is lower than the expected response speed, the drive control amount is learned and corrected so that the response speed becomes faster. Then, the variable valve timing mechanism is driven based on the drive control amount thus learned and corrected. Accordingly, the valve timing is controlled by setting the response speed of the variable valve timing mechanism to a suitable response speed that absorbs individual variations of the engine, the variable valve timing mechanism, the driving means, and the like.

Further, for example, the allowable range of the manufacturing tolerance required for the driving means can be increased. Thereby, the manufacturing cost of the driving means is reduced. further,
For example, it is possible to increase the allowable range of the driving unit with respect to a change with time. Therefore, the period of the periodic replacement of the driving means can be lengthened, and the maintenance cost can be reduced.

Further, for example, an allowable range for adaptability at the time of assembling the driving means can be increased. Therefore, the number of steps for confirming the suitability of the driving means is reduced.

According to a second aspect of the present invention, in the valve timing control device for an internal combustion engine according to the first aspect, the learning of the drive control amount by the drive control amount learning correction means is performed by:
The gist is that the operation is performed only for a predetermined period after the operation of the variable valve timing mechanism.

According to this configuration, after the change of the valve timing by the variable valve timing mechanism, erroneous learning based on, for example, swing of the actual valve timing is prevented. According to a third aspect of the present invention, there is provided a variable valve timing mechanism for changing a valve timing, an operating state detecting means for detecting an operating state of the internal combustion engine, and Target valve timing calculating means for calculating a target value of valve timing, target value delay correcting means for delay correcting the calculation result of the target valve timing calculating means, and actual valve timing for detecting actual valve timing of the variable valve timing mechanism Detecting means, a valve timing change amount detecting means for detecting a change amount of the actual valve timing, and a response speed of the variable valve timing mechanism based on a detection result of the valve timing change amount detecting means. Response speed determining means for determining whether the speed is fast or slow; If the response speed of the variable valve timing mechanism is determined to be faster than the expected response speed based on the determination result of the speed determination device, the target value delay correction device delays the response so that the response speed becomes slower. The learned target value is learned and corrected, and if it is determined that the response speed of the variable valve timing mechanism is lower than the expected response speed, the delay-corrected target value is learned so that the response speed becomes faster. Target value learning correction means for correcting,
Basic drive control amount calculation means for calculating a basic drive control amount of the variable valve timing mechanism based on a learning correction result of the target value learning correction means and a detection result of the actual valve timing detection means; Correction drive control amount calculation means for calculating a correction drive control amount of the variable valve timing mechanism based on the detection result of the means, and drive control based on the calculation results of the basic drive control amount calculation means and the correction drive control amount calculation means The gist of the invention is to provide a driving means for driving the variable valve timing mechanism according to the amount.

According to this configuration, when the response speed determining means determines that the response speed of the variable valve timing mechanism is faster than the expected response speed, the target value is set so that the response speed becomes slower. The target value of the valve timing corrected by the delay correction means is learned and corrected. Similarly, if it is determined that the response speed of the variable valve timing mechanism is lower than the expected response speed, the delay-corrected valve timing target value is learned and corrected so that the response speed becomes faster. ing. And
The basic drive control amount is calculated based on the target value of the valve timing that has been learned and corrected as described above, and the variable valve timing mechanism is driven. Accordingly, the valve timing is controlled by setting the response speed of the variable valve timing mechanism to a suitable response speed that absorbs individual variations of the engine, the variable valve timing mechanism, the driving means, and the like.

Further, for example, the allowable range of the manufacturing tolerance required for the driving means can be increased. Thereby, the manufacturing cost of the driving means is reduced. further,
For example, it is possible to increase the allowable range of the driving unit with respect to a change with time. Therefore, the period of the periodic replacement of the driving means can be lengthened, and the maintenance cost can be reduced.

Further, for example, an allowable range for adaptability at the time of assembling the driving means can be increased. Therefore, the number of steps for confirming the suitability of the driving means is reduced.

According to a fourth aspect of the present invention, in the valve timing control device for an internal combustion engine according to the third aspect, the variable valve timing mechanism operates when the target value learning correction of the target value by the target value learning correction means is corrected. The gist is that it is performed only for a predetermined period after that.

According to this configuration, after the valve timing is changed by the variable valve timing mechanism, erroneous learning based on, for example, swinging of the actual valve timing is prevented. According to a fifth aspect of the present invention, in the valve timing control device for an internal combustion engine according to any one of the first to fourth aspects,
The gist of the determination by the response speed determination means is that the determination is made after being corrected according to at least one of the engine speed and the engine temperature.

According to this configuration, the judgment by the response speed judging means is suitable according to at least one of the engine speed and the engine temperature.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Hereinafter, a first embodiment of a valve timing control device for an internal combustion engine according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system configuration diagram of an automobile engine 1 as an internal combustion engine. The cylinder block 2 of the engine 1 includes a plurality of (only one is shown in FIG. 1) cylinders 3. Piston 4 provided in cylinder 3
Is connected to the crankshaft 5 via a connecting rod 6. The connecting rod 6 converts the reciprocating movement of the piston 4 into rotation of the crankshaft 5.

A cylinder head 7 is mounted above the cylinder block 2. A combustion chamber 8 is formed between the upper end of the piston 4 and the cylinder head 7 in the cylinder 3.

An ignition plug 11 is provided in the combustion chamber 8. An intake port 12 and an exhaust port 13 provided corresponding to the combustion chamber 8 are connected to an intake passage 14 and an exhaust passage 15, respectively. The combustion chamber 8
Injector 1 provided in intake port 12 corresponding to
6 injects fuel toward the combustion chamber 8.

An intake valve 17 and an exhaust valve 18 provided corresponding to the combustion chamber 8 open and close the ports 12 and 13, respectively. The valves 17 and 18 are opened and closed by rotation of cams (not shown) provided on the camshafts 31 and 32 as the intake-side camshaft 31 or the exhaust-side camshaft 32 rotates. Timing pulleys 33 and 34 provided at the tips of the camshafts 31 and 32 are connected to the crankshaft 5 via a timing belt 35 (the connection with the crankshaft 5 is not shown).

That is, when the engine 1 is operating, the rotational force of the crankshaft 5 is applied to each camshaft 3 via the timing belt 35 and the timing pulleys 33 and 34.
1, 32. As the camshafts 31 and 32 rotate, the valves 17 and 18 operate. That is, the valves 17 and 18 are driven to open and close at a predetermined timing in synchronization with the rotation of the crankshaft 5, that is, in response to the reciprocation of each piston 4. The intake valve 17 driven to open and close connects the intake port 12 and the combustion chamber 8.
The exhaust valve 18 that is shut off and opened and closed is driven to the exhaust port 1
3 and the combustion chamber 8 are communicated and shut off.

A crank angle sensor 41 is provided near the crankshaft 5, and the sensor 41 detects the rotational speed NE of the engine 1 (crankshaft 5) and the rotational angle of the crankshaft 5 in a specific cylinder (crank). Angle) etc. are detected. Further, a cam angle sensor 42 is provided near the intake side camshaft 31,
The rotation angle (cam angle) of the camshaft 31 is detected by the sensor 42. Further, the coolant temperature (cooling water temperature) THW of the cooling water of the engine 1 is provided in the cylinder block 2.
Is mounted.

A high voltage output from an igniter 46 is applied to the ignition plug 11. The ignition timing of the ignition plug 11 is determined by the high voltage output timing from the igniter 46. Then, the engine 1 obtains a driving force by causing an air-fuel mixture composed of the intake air from the intake passage 14 and the fuel injected from the injector 16 to explode in the combustion chamber 8 by the spark plug 11 to obtain a driving force. The exhaust gas is discharged to the exhaust passage 8 via the exhaust valve 18.

A part of the intake passage 14 is provided with a surge tank 51 for suppressing pulsation of intake air. On the upstream side of the surge tank 51, a throttle valve 53 whose opening is changed based on the operation of an accelerator pedal 52 is provided. By changing the opening of the throttle valve 53, the amount of air taken into the combustion chamber 8 is adjusted. In the vicinity of the throttle valve 53, a throttle position sensor 54 for detecting its opening (throttle valve opening), and an idle switch 5 which is turned on when the throttle valve 53 is fully closed.
5 is attached. An air flow meter 56 is provided upstream of the throttle valve 53 to detect the mass GN of air taken into the engine per one revolution of the engine.

In the present embodiment, the engine 1 includes the intake camshaft 31 and the timing pulley 33.
A variable valve timing mechanism (hereinafter, referred to as “VVT mechanism”) 60 is provided in a form integrally formed with the above. The VVT mechanism 60 is a well-known mechanism that continuously changes the opening / closing timing of the intake valve 17 by changing the relative rotation phase between the intake camshaft 31 and the timing pulley 33 by the action of hydraulic pressure. That is, VV
The T mechanism 60 is provided with an advance-side hydraulic passage P1 for supplying oil when the relative rotation phase of the intake camshaft 31 is advanced with respect to the rotation of the timing pulley 33, and with the oil when the relative rotation phase is delayed. And a retard-side hydraulic passage P2 for supply. In addition, the valve timing control device that operates the VVT mechanism 60 to change and control the valve timing of the engine 1 includes the two hydraulic passages P1 and P2.
And an oil control valve (hereinafter referred to as "OCV") 63 provided in the middle of the hydraulic passages P1 and P2. Each of the hydraulic passages P1 and P2 is connected to an oil pan 65 via an OCV 63, an oil pump 62 and an oil strainer 64.
It can be connected to. When the oil pump 62 is driven with the operation of the engine 1, the oil pan 6
5 is sucked into an oil pump 62 via an oil strainer 64 and
2 and discharged. This discharged oil is O
The CV 63 selectively feeds the fluid to the hydraulic passages P1 and P2. That is, by selectively switching the communication state between the hydraulic passages P1 and P2 and the oil pump 62 and the oil pan 65 by the OCV 63, the intake camshaft 31 and the timing pulley 33 are selectively switched.
Is changed, and the valve timing is changed.

Here, regarding the above-mentioned OCV 63, FIGS.
This will be described in more detail with reference to FIG. As shown in FIG.
The casing 70 forming the portion 63 has first to fifth ports 71, 72, 73, 74, 75. The first port 71 is in communication with the retard hydraulic passage P2, and the second port 72 is in communication with the advance hydraulic passage P1. Also,
The third and fourth ports 73 and 74 are connected to the oil pan 44, and the fifth port 75 is connected to the discharge side of the oil pump 35.

A skewer-shaped spool 76 is provided inside the casing 70. The spool 76 has four columnar valve bodies 77, which can reciprocate in the axial direction. Further, the casing 70 is provided with an electromagnetic solenoid 78 for continuously moving the spool 76 from the first operating position shown in FIG. 3 to the second operating position shown in FIG. A spring 79 is provided in the casing 70.
9, the spool 76 is urged toward the second operating position.

An electronic control unit (hereinafter, referred to as “ECU”) 80 that controls the operating state of the engine 1 performs duty control of the driving mode of the electromagnetic solenoid 78. That is,
The ECU 80 maintains the position of the spool 76 at the first operating position by driving the electromagnetic solenoid 78 at a duty ratio of 100%. Thereby, as shown in FIG. 3, the advanced hydraulic pressure passage P1 is connected to the discharge side of the oil pump 62 via the second port 72 and the fifth port 75, while the retard hydraulic pressure passage P2 is connected. Are connected to the oil pan 65 via the first port 71 and the third port 73. As a result, the advance-side hydraulic passage P is provided to the VVT mechanism 60.
1 while oil is supplied from the VVT mechanism 60 to the oil pan 65 through the retard hydraulic pressure passage P2. The VVT mechanism 60 operates to advance the relative rotation phase of the intake camshaft 31 with respect to the rotation of the timing pulley 33.

The ECU 80 includes an electromagnetic solenoid 78
Is driven at a duty ratio of 0% (the energization of the electromagnetic solenoid 78 is stopped) to maintain the position of the spool 76 at the second operating position. Thereby, as shown in FIG. 4, the retard hydraulic pressure passage P2 is connected to the discharge side of the oil pump 62 via the first port 71 and the fifth port 75, while the advance hydraulic pressure passage P1 is connected. Is the second port 7
The oil pan 65 is connected via the second and fourth ports 74. As a result, while oil is supplied to the VVT mechanism 60 through the retard hydraulic pressure passage P2, the VVT mechanism 60
Oil from the oil pan 6 through the advance side hydraulic passage P1.
Returned to 5. The VVT mechanism 60 operates to delay the relative rotation phase of the intake camshaft 31 with respect to the rotation of the timing pulley 33.

Further, the ECU 80 keeps the position of the spool 76 at the intermediate position shown in FIG. 5 by driving the electromagnetic solenoid 78 at a duty ratio of 50%. Thus, the valve body 77 of the spool 76 closes the first and second ports 71 and 72. As a result, the advance side hydraulic passage P1
Oil is not supplied to or discharged from the retard hydraulic passage P2, and the relative rotation phase of the intake camshaft 31 with respect to the rotation of the timing pulley 33 is maintained as it is.

The response speed when the VVT mechanism 60 advances the relative rotation phase of the intake camshaft 31 with respect to the rotation of the timing pulley 33 is continuous when the duty ratio of the electromagnetic solenoid 78 is in the range of 50% to 100%. It is controlled by being changed. That is, the ECU 80
Sets the duty ratio of the electromagnetic solenoid 78 to 50% to 10%.
By continuously changing the flow rate within the range of 0%, the flow rate of the oil supplied to the VVT mechanism 60 through the advance hydraulic pressure passage P1 is controlled. Thereby, the response speed of the VVT mechanism 60 is such that the duty ratio of the electromagnetic solenoid 78 is 50%.
It is controlled to increase as the value increases in the range of 100%.

On the other hand, the response speed when the VVT mechanism 60 slows down the relative rotation phase of the intake camshaft 31 with respect to the rotation of the timing pulley 33 is determined when the duty ratio of the electromagnetic solenoid 78 is in the range of 50% to 0%. It is controlled by continuous changes. That is, the ECU 80
Sets the duty ratio of the electromagnetic solenoid 78 to 50% to 0%.
, The flow rate of the oil supplied to the VVT mechanism 60 through the retard hydraulic pressure passage P2 is controlled. As a result, the response speed of the VVT mechanism 60 is set such that the duty ratio of the electromagnetic solenoid 78 is 50% to 0%.
In the range of%, the control is made to be faster as the value becomes smaller.

Next, the configuration of the ECU 80 will be described with reference to the block diagram of FIG. As shown in FIG.
The CU 80 is composed of a digital computer, and a RAM (random access memory) 82, a backup RAM 83, a ROM interconnected via a bus 81.
(Read only memory) 84, a CPU (central processing unit) 85 composed of a microprocessor, an input port 86 and an output port 87.

Here, the CPU 85 executes various arithmetic processes according to a control program and initial data stored in the ROM 84 in advance. Further, the RAM 82 temporarily stores the calculation result by the CPU 85. Backup RAM
Reference numeral 83 denotes a non-volatile memory that is backed up by a battery, and stores and holds necessary calculation results even after the engine 1 is stopped.

The crank angle sensor 41, cam angle sensor 42, water temperature sensor 43, throttle position sensor 5
4. Detection signals from the idle switch 55, the air flow meter 56 and the like are input to the input port 86. The operating state of the engine 1 is detected by these sensors 41 to 43 and 54 to 56.

On the other hand, the output port 87 is connected to the injector 16, the igniter 46, the OCV 63 and the like via the corresponding drive circuits and the like. Then, the ECU 80
(CPU 85) are the above-mentioned respective sensors 41 to 43, 54 to 5
6, the injector 16, the igniter 46, and the OCV 63 (the VVT mechanism 6) in accordance with the control program and the initial data stored in the ROM 84.
0) and the like are suitably controlled.

Next, the operation of the engine system thus configured as a device for mainly controlling the VVT mechanism 60 to control the valve timing change will be described.
The following description focuses on the processing by.

FIG. 6 is a flowchart showing a routine for calculating a target valve timing (target advance value) executed by the ECU 80. Note that this routine is periodically executed by a fixed time interruption every 8 ms (millisecond), for example.

When the process proceeds to this routine, first, at step 101, the CPU 85 determines whether the engine speed N
E and air mass GN per revolution of the engine are stored in RAM
82, the process proceeds to step 102.

In step 102, the CPU 85 uses the map based on the engine speed NE and the air mass GN per one revolution of the engine shown in FIG.
Calculate TT. This map is stored in the ROM 84 in advance. Note that the target advance value VTT is
The actual target advance value when the intake camshaft 31 is relatively rotated with respect to the rotation of the timing pulley 33 is described as being converted into a crank angle (° CA).
The target advance value VTT when the valve timing is delayed to the maximum is 0 ° CA, and the target advance value VTT when the valve timing is advanced to the maximum is 60 ° CA.

In step 102, the target advance value VTT
The CPU 85 that has calculated the translation angle value VTT
After that, the subsequent processing is temporarily ended. Next, E
The duty ratio calculation routine of the OCV 63 executed by the CU 80 will be described with reference to FIG. This routine is also periodically executed by a fixed-time interruption every 8 ms (millisecond), for example.

When the process proceeds to this routine, first, in step 201, the CPU 85 determines whether the engine speed N
E, the actual valve timing (actual advance value) VT, the change amount of valve timing (advance value change amount) ΔVT, and the duty ratio learning correction value K are read from the RAM 82 or the backup RAM 83. The actual advance angle value VT is calculated based on the cam angle detected by the cam angle sensor 42 and the crank angle detected by the crank angle sensor 41. This actual advance value VT is also converted to a crank angle (° CA), similarly to the target advance value VTT. The advance value change amount ΔVT is calculated and stored in a duty ratio learning correction value calculation routine described later, and indicates the degree of change in valve timing. Further, the duty ratio learning correction value K is also calculated and stored in a duty ratio learning correction value calculation routine to be described later, and includes the engine 1, the VVT mechanism 60, and the OCV.
This is a correction value for absorbing variation in the response speed of the VVT mechanism 60 based on individual variation such as 63.

The CPU 85 that has read the engine speed NE, the actual advance value VT, the advance value change amount ΔVT, and the duty ratio learning correction value K as described above proceeds to step 202.

In step 202, the CPU 85 calculates a deviation Ek between the target advance value VTT and the actual advance value VT, and proceeds to step 203. In step 203, the CP
U85 calculates the basic duty ratio DUB and the correction duty ratio DUD using the map based on the deviation Ek shown in FIG. 10 and the map based on the advance value change amount ΔVT shown in FIG. These maps are stored in the ROM 84 in advance.

The basic duty ratio DUB is a basic duty ratio of the OCV 63, and is equal to the engine speed N.
It is calculated based on E and the deviation Ek. FIG.
As shown in (2), the basic duty ratio DUB has a larger value from 50% to 100% as the engine speed NE is smaller and the deviation Ek is larger on the positive side. This is because there is a large deviation on the plus side, that is, the target advance value VT.
This is because the response speed of the VVT mechanism 60 to the advance side is improved in response to the fact that the actual advance value VT is significantly delayed from T. Similarly, the basic duty ratio DUB is
The smaller the engine speed NE and the larger the deviation Ek on the negative side, the smaller the value from 50% to 0%. This is because the response speed of the VVT mechanism 60 to the retard side is improved in response to the large deviation on the negative side, that is, the fact that the actual advance value VT is greatly advanced from the target advance value VTT. It is.

On the other hand, the correction duty ratio DUD is calculated based on the amount of change of the advance angle value ΔVT. FIG.
As shown in FIG. 1, the correction duty ratio DUD has a larger value on the plus side as the lead angle change amount ΔVT is larger on the plus side. This is in order to cope with the necessity of changing the VVT mechanism 60 to the advance side as the advance value change amount ΔVT increases toward the plus side. Similarly, the correction duty ratio DUD has a larger value on the negative side as the advance value change amount ΔVT is larger on the negative side. This is because the larger the amount of change of the advance value ΔVT is on the negative side,
This is to cope with a high necessity of changing the VVT mechanism 60 to the retard side. The correction duty ratio DUD
Is closer to zero as the advance value change amount ΔVT is closer to zero. This is because the operation of the VVT mechanism 60 approaches convergence as the advance value change amount ΔVT is closer to zero.

After calculating the basic duty ratio DUB and the correction duty ratio DUD, the CPU 85 proceeds to step 204. In step 204, the CPU 85 determines whether or not a value (DUB + DUD) obtained by adding the basic duty ratio DUB and the correction duty ratio DUD is 50% or more. Here, if the value (DUB + DUD) is determined to be 50% or more, the CPU 85 determines that the VVT mechanism 60 is changing to the advance side, and proceeds to step 205. Then, in step 205, the VVT mechanism 60
In order to absorb the variation of the response speed corresponding to the change in the advance angle, the value obtained by adding the duty ratio learning correction value K to the above value (DUB + DUD) is set as the duty ratio DU of the OCV 63.

On the other hand, if it is determined in step 204 that the value (DUB + DUD) is less than 50%, the CPU
In step 85, it is determined that the VVT mechanism 60 has changed to the retard side, and the flow proceeds to step 206. In step 206, the value obtained by subtracting the duty ratio learning correction value K from the above value (DUB + DUD) is used as the duty ratio of the OCV 63 in order to absorb the variation in the response speed corresponding to the change of the VVT mechanism 60 to the retard side. DU.

In step 205 or 206,
After calculating the duty ratio DU, the CPU 85 stores the duty ratio DU in the RAM 82 and then temporarily ends the subsequent processing.

Incidentally, the OCV 63 has the duty ratio DU.
, The oil supplied to the VVT mechanism 60 is controlled, and VV is controlled at a response speed corresponding to the duty ratio DU.
The T mechanism 60 operates to control the valve timing.

Next, the duty ratio learning correction value calculation routine executed by the ECU 80 will be described with reference to FIG. This routine is executed by a predetermined crank angle based on the crank angle detected by the crank angle sensor 41, for example, at an angle of 240 ° CA.

When the process proceeds to this routine, the CPU 85 first reads the actual advance value VT and the duty ratio DU in step 301, and proceeds to step 302. In step 302, the CPU 85 calculates the advance value change amount ΔVT from the difference between the current actual advance value VT and the previously detected actual advance value VTi−1, and proceeds to step 303.

In step 303, the CPU 85 updates the advance value VTi-1 to the current actual advance value VT, and proceeds to step 304. In step 304, the CP
U85 determines whether the duty ratio DU is 100%. Here, when it is determined that the duty ratio DU is not 100%, the CPU 85 temporarily ends the processing without calculating and updating the duty ratio learning correction value K.

In step 304, the duty ratio DU
Is determined to be 100%, the CPU 85 proceeds to step 305. In step 305, the CPU 8
5 determines whether or not the advance value change amount ΔVT is equal to or greater than a predetermined value S. Here, if it is determined that the advance angle change amount ΔVT is equal to or greater than the predetermined value S, the CPU 85 determines that the VVT mechanism 60 is controlled at a response speed higher than the expected response speed, and proceeds to step 306. Transition. The reason why the VVT mechanism 60 is controlled at a response speed higher than the expected response speed is that the engine 1, the VVT mechanism 60,
This is due to individual variations such as CV63.

The CPU 85 that has proceeded to step 306
The duty ratio learning correction value K is updated to a value obtained by subtracting a predetermined value α from the current duty ratio learning correction value K. The reason why the duty ratio learning correction value K is updated in this way is that the duty ratio DU is corrected by an amount faster than the expected response speed of the VVT mechanism 60, and the response speed of the VVT mechanism 60 is reduced. That's why.

On the other hand, if it is determined that the advance angle change amount ΔVT is less than the predetermined value S, the CPU 85 determines that the VVT mechanism 60 is controlled at a response speed lower than the expected response speed, and proceeds to step Move to 307. The reason why the VVT mechanism 60 is controlled at a response speed lower than the expected response speed is also due to individual variations of the engine 1, the VVT mechanism 60, the OCV 63, and the like.

The CPU 85 that has proceeded to step 307
The duty ratio learning correction value K is updated to a value obtained by adding a predetermined value α to the current duty ratio learning correction value K. The reason why the duty ratio learning correction value K is updated in this way is that the duty ratio DU is corrected by an amount lower than the expected response speed of the VVT mechanism 60, and the response speed of the VVT mechanism 60 is increased. That's why.

In step 306 or 307,
After calculating the duty ratio learning correction value K, the CPU 85 stores the learning correction value K in the RAM 82 and the backup RAM 83.
After that, the subsequent processing is temporarily ended.

The duty ratio learning correction value K calculated as described above is read in step 201 of the above-described duty ratio calculation routine, and the duty ratio DU is calculated.
Is used for calculation. Therefore, the duty ratio DU calculated in this routine depends on the engine 1 and the VVT mechanism 6.
0, a suitable value for absorbing the variation in the response speed caused by individual variations such as OCV63. As a result, the response speed of the VVT mechanism 60 is reduced by the engine 1 or V
The valve timing is controlled to a suitable response speed that absorbs individual variations of the VT mechanism 60, the OCV 63, and the like.

As described in detail above, according to the present embodiment, the following effects can be obtained. (1) In the present embodiment, the response speed of the VVT mechanism 60 is
The valve timing can be controlled with a suitable response speed that absorbs individual variations of the engine 1, the VVT mechanism 60, the OCV 63, and the like.

(2) In this embodiment, the engine 1 and the VV
Variations in the response speed caused by individual variations in the T mechanism 60 and the OCV 63 can be absorbed. Therefore, for example, the tolerance of the manufacturing tolerance required for the OCV 63 can be increased. Thereby, the manufacturing cost of the OCV 63 can be reduced.

Further, for example, the allowable range of the OCV 63 with respect to a change with time can be increased. Therefore, OCV
It is possible to lengthen the period of the regular replacement and the like of 63, and to reduce the maintenance cost.

Further, for example, the tolerance for the compatibility at the time of assembling the OCV 63 can be increased. Therefore, the number of steps for confirming the suitability of the OCV 63 can be reduced.

(Second Embodiment) Hereinafter, a second embodiment of a valve timing control device for an internal combustion engine according to the present invention will be described in detail with reference to the drawings.

The system configuration of the engine according to this embodiment is the same as that of the first embodiment, and a description thereof will be omitted. In the present embodiment, a delay process (hereinafter, “smoothing process”) is performed for the operation of the VVT mechanism 60.
), And by correcting the mode of the simulated processing, the response speed of the VVT mechanism 60 is adjusted to a suitable response speed that absorbs individual variations of the engine 1, the VVT mechanism 60, and the OCV 63. This is different from the first embodiment. The reason why the smoothing process is performed on the operation of the VVT mechanism 60 is based on the premise that the response speed of the VVT mechanism 60 tends to be higher.

Hereinafter, the VVT mechanism 60 of the present embodiment will be mainly described.
The operation as a device for controlling the change of the valve timing by operating the ECU will be described, focusing on the processing by the ECU 80. FIG. 12 is a flowchart showing a target advance value calculation routine executed by the ECU 80. Note that this routine is periodically executed by a fixed time interruption every 8 ms (millisecond), for example.

When the process proceeds to this routine, first, at step 501, the CPU 85 determines whether the engine speed N
E and the mass GN of air per revolution of the engine and the smoothing rate learning correction value KNMS are read from the RAM 82 or the backup RAM 83, and the routine proceeds to step 502. The smoothing rate learning correction value KNMS is calculated and stored in a smoothing rate learning correction value calculation routine to be described later, and performs a smoothing process for the operation of the VVT mechanism 60 and also adds the same to the smoothing process. Engine 1 and VVT
VV based on individual variation such as mechanism 60, OCV63
This is a correction value for absorbing variation in the response speed of the T mechanism 60.

In step 502, the CPU 85 determines the engine speed NE shown in FIG. 9 as in the first embodiment.
A target advance value VTT is calculated from a map based on the air mass GN per one revolution of the engine and a step 50.
Move to 3.

In step 503, the CPU 85 calculates the final target advance value VTF as follows: VTF = KNMS × VTT. By multiplying the target advance value VTT by the smoothing rate learning correction value KNMS, the final target advance value VTF is smoothed, and the engine 1 and VV are processed.
V based on individual variations such as T mechanism 60 and OCV63
A correction for absorbing the variation in the response speed of the VT mechanism 60 is also made.

In step 503, after calculating the final target advance value VTF, the CPU 85 stores the advance value VTF in the RAM 82, and thereafter temporarily terminates the subsequent processing. Next, a duty ratio calculation routine of the OCV 63 executed by the ECU 80 will be described with reference to FIG. This routine is also periodically executed by a fixed-time interruption every 8 ms (millisecond), for example.

When the process proceeds to this routine, first, at step 601, the CPU 85 determines whether the engine speed N
E, the actual advance value VT and the advance value change amount ΔVT are stored in the RAM 82
, And the process proceeds to step 602.

In step 602, the CPU 85 calculates a deviation Ek between the final target advance value VTF and the actual advance value VT, and proceeds to step 603. In step 603, the CPU 85 determines the basic duty ratio DU based on the map based on the deviation Ek shown in FIG. 10 and the map based on the advance angle variation ΔVT shown in FIG.
B and the correction duty ratio DUD are calculated, and the process proceeds to step 604.

In step 604, the CPU 85 sets the duty ratio DU of the OCV 63 to a value (DUB + DUD) obtained by adding the basic duty ratio DUB and the correction duty ratio DUD.

At step 604, the duty ratio D
After calculating U, the CPU 85 calculates the duty ratio DU as RA
After storing the result in M82, the subsequent processing ends once. When the OCV 63 is controlled to the duty ratio DU, the oil supplied to the VVT mechanism 60 is controlled, and the VVT mechanism 60 operates at a response speed according to the duty ratio DU.

Next, the smoothing rate learning correction value calculation routine executed by the ECU 80 will be described with reference to FIG. This routine is executed at a predetermined crank angle based on the crank angle detected by the crank angle sensor 64, for example, at an angle of 240 ° CA.

When the process proceeds to this routine, the CPU 85 first reads the actual advance value VT and the duty ratio DU in step 701, and proceeds to step 702. In step 702, the CPU 85 calculates the advance value change amount ΔVT from the difference between the current actual advance value VT and the previously detected actual advance value VTi−1, and proceeds to step 703.

In step 703, the CPU 85 updates the advance value VTi-1 to the current actual advance value VT, and proceeds to step 704. In step 704, the CP
U85 determines whether the duty ratio DU is 100%. If it is determined that the duty ratio DU is not 100%, the CPU 85 determines that the smoothing rate learning correction value KNMS
The processing is once ended without calculating and updating.

At step 704, duty ratio DU
Is determined to be 100%, the CPU 85 proceeds to step 705. In step 705, the CPU 8
5 determines whether or not the advance value change amount ΔVT is equal to or greater than a predetermined value T. Here, if it is determined that the advance value change amount ΔVT is equal to or greater than the predetermined value T, the CPU 85 determines that the VVT mechanism 60 is operating at a response speed higher than the expected response speed, and proceeds to step 706. Transition.

The CPU 85, which has proceeded to step 706,
The smoothing rate learning correction value KNMS is updated to a value obtained by subtracting a predetermined value β from the current smoothing rate learning correction value KNMS. The reason why the smoothing rate learning correction value KNMS is reduced in this manner is that VV
The degree of smoothing of the target advance value VTT is increased by an amount corresponding to the response speed of the T mechanism 60 being higher than the expected response speed, and the duty ratio DU is corrected in accordance therewith, and the VVT mechanism 60 is adjusted.
This is to reduce the response speed of the device.

On the other hand, when it is determined that the advance angle change amount .DELTA.VT is less than the predetermined value T, the CPU 85 determines that the VVT mechanism 60 is operating at a response speed lower than the expected response speed, and proceeds to step S1. The process moves to 707.

The CPU 85 that has proceeded to step 707
The smoothing rate learning correction value KNMS is updated to a value obtained by adding a predetermined value β to the current smoothing rate learning correction value KNMS. The reason for adding the smoothing rate learning correction value KNMS in this manner is that VV
The degree of smoothing of the target advance value VTT is reduced by the amount by which the response speed of the T mechanism 60 is lower than the expected response speed, and the duty ratio DU is corrected in accordance with the weakness.
This is to increase the response speed of the system.

In step 706 or 707,
The CPU 85 that has calculated the smoothing rate learning correction value KNMS,
The learning correction value KNMS is stored in the RAM 82 and the backup R
After the data is stored in the AM 83, the subsequent processing is temporarily terminated.

The smoothing rate learning correction value KNMS calculated as described above is read in step 501 of the above-described target advance value calculation routine, and is used for calculating the final target advance value VTF. . Then, the target advance value VTF calculated in this routine is read in step 601 of the above-described duty ratio calculation routine, and is used for calculating the duty ratio DU. Therefore, the duty ratio DU calculated in this manner is equal to the VV caused by individual variations of the engine 1, the VVT mechanism 60, the OCV 63, and the like.
This is a suitable value for absorbing the variation in the response speed of the T mechanism 60. As a result, the VVT mechanism 60 operates at a suitable response speed that absorbs individual variations of the engine 1, the VVT mechanism 60, the OCV 63, and the like, and the valve timing is controlled.

As described in detail above, according to the present embodiment, the same effects as (1) and (2) of the first embodiment can be obtained. Note that the embodiment of the present invention is not limited to the above-described embodiment, and may be modified as follows.

In the first embodiment, the correction value of the duty ratio learning correction value K when the response speed of the VVT mechanism 60 is faster than the expected response speed and when the response speed is lower than the expected response speed are set to the same predetermined value α. However, these correction values may be different from each other.

In the first embodiment, the calculation and update of the duty ratio learning correction value K are performed with the predetermined value α. However, the value for the calculation and update is not the predetermined value, but is, for example, the advance angle change amount ΔVT. May be set to a value corresponding to the deviation between the value and the predetermined value S.

In the second embodiment, the correction value of the smoothing rate learning correction value KNMS when the response speed of the VVT mechanism 60 is faster than the expected response speed and when the response speed is lower than the expected response speed are set to the same predetermined value β. However, these correction values may be different from each other.

In the second embodiment, the update of the smoothing rate learning correction value KNMS is performed with the predetermined value β. However, the value for this calculation and update is not the predetermined value, but is, for example, the amount of change in the advance angle value. The value may be a value corresponding to a deviation between ΔVT and the predetermined value T.

In the second embodiment, the final target advance value VTF is calculated by multiplying the target advance value VTT by the smoothing rate learning correction value KNMS. On the other hand, the final target advance value VTF is calculated by, for example, VTF = KNMS × (VTT−VTTi−1) + VTT based on the current target advance value VTT and the previously calculated target advance value VTTi−1.
i-1 may be calculated.

In each of the above embodiments, the predetermined value S or the predetermined value is used to determine whether the VVT mechanism 60 is operating at a higher response speed than the expected response speed or at a lower response speed. Although T is employed, the value for this determination is not a predetermined value, but may be a value obtained according to, for example, the cooling water temperature THW or the engine speed NE. In particular, the cooling water temperature THW corresponds to the temperature of the engine 1, that is, the temperature of the hydraulic oil, and the VVT mechanism 60
It affects the response speed. Therefore, the cooling water temperature T
By determining the response speed of the VVT mechanism 60 according to the HW (oil temperature), the response speed can be made more suitable.

Since the response speed of the VVT mechanism 60 depends on the cooling water temperature THW (oil temperature), the response speed of the VVT mechanism 60 is determined only in a specific temperature range. You may.

The same applies to the engine speed NE. In the above-described embodiments, the advance angle change amount ΔVT, that is, the difference between the actual advance angle value VT and the previously detected actual advance angle value VTi-1 is employed as an indication of the degree of fluctuation of the valve timing. This may employ, for example, the average value of the actual advance values detected at a plurality of timings.

In the above embodiments, the duty ratio learning correction value K or the smoothing rate learning correction value KNMS
Is updated only when the duty ratio DU is 100%, but this is done, for example, when the duty ratio DU is 50% or 0%.
It may be performed only at other duty ratios DU. Further, the duty ratio DU may be divided into a plurality of areas according to the values, and the duty ratio learning correction value K or the smoothing rate learning correction value KNMS may be calculated and updated for each area.

In each of the above embodiments, the calculation update of the duty ratio learning correction value K or the smoothing rate learning correction value KNMS is always executed at every predetermined crank angle (240 ° CA). It may be executed only for a predetermined period after the mechanism 60 operates. This is because the actual advance value VT fluctuates even after the target advance value VTT is set to be constant, as shown in FIG. 15 showing an example of transition of the target advance value VTT and the actual advance value VT. It depends. If the calculation update of the duty ratio learning correction value K or the smoothing rate learning correction value KNMS is continued in such a state, erroneous learning will be performed. Such erroneous learning can be prevented by updating the calculation of the duty ratio learning correction value K or the smoothing rate learning correction value KNMS only for a predetermined period after the operation of the VVT mechanism 60.

In each of the above embodiments, the VVT mechanism 60 is provided on the intake side camshaft 31 so that the intake valve 17
The case of changing the opening and closing timing of
A VVT mechanism 60 may be provided on the exhaust side camshaft 32 to change the opening / closing timing of the exhaust valve 18. In addition, VVT is applied to both camshafts 31 and 32 respectively.
A configuration in which the mechanism 60 is provided may be employed.

[0098]

According to the first and third aspects of the present invention, the response speed of the variable valve timing mechanism is set to a suitable response speed that absorbs individual variations of the internal combustion engine, the variable valve timing mechanism, the driving means, and the like. Valve timing can be controlled.

According to the second and fourth aspects of the present invention, it is possible to prevent erroneous learning based on swing of the actual valve timing after changing the valve timing by the variable valve timing mechanism.

According to the fifth aspect of the present invention, the determination by the response speed determining means can be made suitable in accordance with at least one of the engine speed and the engine temperature.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a valve timing control device according to the present invention.
1 is a schematic diagram illustrating an outline of an engine system to which an embodiment is applied.

FIG. 2 is an exemplary block diagram showing the electrical configuration of the embodiment.

FIG. 3 is a sectional view showing an operation mode of the OCV.

FIG. 4 is a sectional view showing an operation mode of the OCV.

FIG. 5 is a sectional view showing an operation mode of the OCV.

FIG. 6 is a flowchart showing a control mode of the embodiment.

FIG. 7 is a flowchart showing a control mode of the embodiment.

FIG. 8 is a flowchart showing a control mode of the embodiment.

FIG. 9 is a map showing a relationship between an engine speed, an air mass, and a target advance angle value.

FIG. 10 is a map showing a relationship between an engine speed and a deviation and a basic duty ratio.

FIG. 11 is a map showing a relationship between a lead angle change amount and a correction duty ratio.

FIG. 12 is a flowchart illustrating a control mode of a second embodiment of the valve timing control device according to the present invention.

FIG. 13 is a flowchart showing a control mode of the embodiment.

FIG. 14 is a flowchart showing a control mode of the embodiment.

FIG. 15 is a graph showing transitions of a target advance value and an actual advance value.

[Explanation of symbols]

17: intake valve, 42: cam angle sensor, 60: VVT
Mechanism, 63 ... OCV, 80 ... ECU.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 3G092 AA01 AA11 DA01 DA10 DF04 EA03 EA04 EA08 EA11 EA16 EA17 EA25 EB00 EB01 EB06 EC05 EC08 FA07 FA44 FA48 HA01Z HA13X HA13Z HE01Z HE03Z HE08Z 3G301 HA01 NA07 JA08 LC08 NC02 ND21 ND22 ND41 NE11 NE12 NE22 NE23 PA01Z PA11Z PA14Z PE01Z PE03Z PE08Z PE10Z

Claims (5)

[Claims] A variable valve timing mechanism for changing a valve timing; an operating state detecting means for detecting an operating state of the internal combustion engine; and a valve timing of the variable valve timing mechanism based on a detection result of the operating state detecting means. Target valve timing calculation means for calculating a target value; actual valve timing detection means for detecting actual valve timing of the variable valve timing mechanism; valve timing change amount detection means for detecting a change amount of the actual valve timing; A basic drive control amount calculation unit that calculates a basic drive control amount of the variable valve timing mechanism based on a calculation result of the target valve timing calculation unit and a detection result of the actual valve timing detection unit; Based on the detection result, the variable valve timing A correction drive control amount calculation means for calculating a correction drive control amount of the variable mechanism, and a response speed of the variable valve timing mechanism is faster or slower than an expected response speed based on a detection result of the valve timing change amount detection means. Response speed determining means for determining whether the response speed of the variable valve timing mechanism is faster than an expected response speed based on the determination result of the response speed determining means, The drive control amount based on the calculation results of the basic drive control amount calculation means and the correction drive control amount calculation means is learned and corrected so that the response speed of the variable valve timing mechanism is lower than the expected response speed. In this case, the drive control amount learning correction means for learning and correcting the drive control amount so as to increase the response speed; and Ri learning corrected by the drive control amount, a valve timing control apparatus for an internal combustion engine, which driving means for driving the variable valve timing mechanism, comprising the. 2. The valve timing control device for an internal combustion engine according to claim 1, wherein the drive control amount learning correction by the drive control amount learning correction unit is performed only for a predetermined period after the operation of the variable valve timing mechanism. A valve timing control device for an internal combustion engine, comprising: A variable valve timing mechanism for changing a valve timing; an operating state detecting means for detecting an operating state of the internal combustion engine; and a valve timing of the variable valve timing mechanism based on a detection result of the operating state detecting means. Target valve timing calculation means for calculating a target value; target value delay correction means for delay correcting the calculation result of the target valve timing calculation means; actual valve timing detection means for detecting actual valve timing of the variable valve timing mechanism. A valve timing change amount detecting means for detecting a change amount of the actual valve timing; and, based on a detection result of the valve timing change amount detecting means, whether a response speed of the variable valve timing mechanism is faster than an expected response speed. Response speed determining means for determining whether the response speed is low; If the response speed of the variable valve timing mechanism is determined to be faster than the expected response speed based on the result of the determination by the determination means, the delay is corrected by the target value delay correction means so that the response speed becomes slower. When the response speed of the variable valve timing mechanism is determined to be lower than the expected response speed, the delay-corrected target value is learned and corrected so that the response speed becomes faster. Target value learning correction means, and basic drive control amount calculation means for calculating a basic drive control amount of the variable valve timing mechanism based on a learning correction result of the target value learning correction means and a detection result of the actual valve timing detection means. Correction drive control for calculating a correction drive control amount of the variable valve timing mechanism based on a detection result of the valve timing change amount detection means. An internal combustion engine comprising: calculation means; and drive means for driving a variable valve timing mechanism with a drive control amount based on the calculation results of the basic drive control amount calculation means and the correction drive control amount calculation means. Valve timing control device. 4. The valve timing control device for an internal combustion engine according to claim 3, wherein the learning of the target value of the valve timing by the target value learning correcting means is performed only for a predetermined period after the operation of the variable valve timing mechanism. A valve timing control device for an internal combustion engine, wherein the control is performed. 5. The valve timing control device for an internal combustion engine according to claim 1, wherein the determination by the response speed determination unit is corrected according to at least one of an engine speed and an engine temperature. A valve timing control device for an internal combustion engine, which is determined.