JP6689778B2 - Control device and control method for variable valve timing device - Google Patents

Description

  The present invention relates to a control device and a control method for a variable valve timing device that makes a relative rotation phase of a cam shaft relative to a crank shaft of an internal combustion engine variable.

  Patent Document 1 discloses a variable valve timing device that changes the valve timing of an intake valve or an exhaust valve that is driven to open and close by a camshaft by changing the rotational phase of the camshaft with respect to the crankshaft of an internal combustion engine. There is disclosed a control device for a variable valve timing device configured to change a rotation phase by adjusting a rotation speed of a motor with respect to a rotation speed of a shaft.

  Then, the control device disclosed in Patent Document 1 calculates the actual valve timing at the time of outputting the cam angle signal based on the crank angle signal output from the crank angle sensor and the cam angle signal output from the cam angle sensor. At the same time, the valve timing change amount with respect to the actual valve timing at the time of outputting the cam angle signal is calculated based on the rotational speed difference between the motor and the cam shaft, and the actual valve timing and the valve timing change amount at the time of outputting the cam angle signal are used. Calculate the final actual valve timing.

JP, 2004-162706, A

  The control device of the variable valve timing device detects the rotational phase of the cam shaft with respect to the crank shaft based on the crank angle signal output at the predetermined rotation position of the crank shaft and the cam signal output at the predetermined rotation position of the cam shaft. In this case, for example, the crank angle from the generation timing of the crank angle signal to the generation timing of the cam signal is detected as a value corresponding to the rotation phase. That is, the detected value of the rotation phase is updated at each generation timing of the cam signal, and the detection cycle (ms) of the rotation phase changes according to the rotation speed of the internal combustion engine.

On the other hand, the control device calculates the operation amount of the variable valve timing device based on the detected value of the rotational phase and the set value (target value) in a fixed cycle (constant time cycle), for example, according to the control deviation. The operation amount is changed by the PID operation (proportional operation, integral operation, differential operation).
Therefore, even if the speed at which the actual rotation phase approaches the set value (control deviation change speed) is constant, if the rotation phase detection cycle and the operation amount (differential term) calculation cycle are different, The deviation between the calculation timing of the amount and the detection timing of the rotation phase changes at each calculation timing of the manipulated variable, so the value of the differential term proportional to the derivative of the control deviation fluctuates (hunting), and the convergence to the set value is stable. There was a case where the sex was impaired.

Therefore, the present invention can suppress the variation of the differential term according to the change of the control deviation due to the difference between the update timing of the detected value of the rotation phase and the calculation timing of the operation amount, and thus the convergence of the rotation phase is achieved. An object of the present invention is to provide a control device and a control method for a variable valve timing device that can improve stability.

Therefore, the control device according to the present invention is a control device for a variable valve timing device that varies the rotational phase of a cam shaft with respect to the crank shaft of an internal combustion engine, and a crank angle signal output at a predetermined rotational position of the crank shaft. And a control unit that calculates and outputs an operation amount of the variable valve timing device based on a detected value of the rotational phase obtained from a cam signal output at a predetermined rotational position of the cam shaft, and the control unit is The operation amount is calculated and output by PID control so that the detected value approaches the set value, the change amount of the detected value is obtained at the detection cycle of the rotation phase, and the set value is obtained at a fixed cycle. Is calculated, and the differential term is calculated based on the deviation between the change amount of the detected value of the rotation phase and the change amount of the set value .

Further, a control method according to the present invention is a control method for a variable valve timing device that varies a rotational phase of a camshaft with respect to a crankshaft of an internal combustion engine, and a crank angle signal output at a predetermined rotational position of the crankshaft. And a cam signal output at a predetermined rotation position of the cam shaft, a step of obtaining a detected value of the rotational phase, a step of obtaining a variation amount of the detected value at a detection cycle of the rotational phase, and a change at a fixed cycle. seen containing a step of computing the manipulated variable PID control of the based on the amount the variable valve timing device, a step of calculating the manipulated variable comprises the steps of calculating the set value of the rotation phase, in the fixed period step for calculating a derivative term based on the deviation of the step of calculating a change amount of the set value, the change amount of the set value change amount and the detection value of the rotational phase And, including the.

According to the above invention, it is possible to suppress the variation of the differential term according to the change of the control deviation due to the difference between the update timing of the detected value of the rotation phase and the calculation timing of the operation amount, and thus the convergence of the rotation phase is stabilized. You can improve your sex.

It is a block diagram of the internal combustion engine in the embodiment of the present invention. It is a block diagram of a crank angle sensor and a cam sensor in an embodiment of the present invention. 6 is a time chart showing waveforms of a crank angle signal CRANK and a cam signal CAM in the embodiment of the present invention. 6 is a time chart for explaining a method of measuring a rotational phase in the embodiment of the present invention. 5 is a flowchart showing a manipulated variable setting process executed by a crank angle signal CRANK interrupt in the embodiment of the present invention. 7 is a flowchart showing a manipulated variable setting process executed by a cam signal CAM interrupt in the embodiment of the present invention. 6 is a flowchart showing a manipulated variable setting process executed by a fixed cycle (10 ms) interrupt in the embodiment of the present invention. It is a functional block diagram which shows the arithmetic processing of the differential term in embodiment of this invention.

Embodiments of the present invention will be described below.
FIG. 1 is a diagram showing an example of a vehicle internal combustion engine to which a control device for a variable valve timing device according to the present invention is applied.

The internal combustion engine 101 is a 4-cylinder 4-cycle spark ignition engine mounted on a vehicle (not shown) as a drive source.
The intake air amount sensor 103 is arranged in the intake duct 102 and detects the intake air flow rate QA of the internal combustion engine 101.

The intake valve 105 opens and closes the intake port of the combustion chamber 104 of each cylinder.
The fuel injection valve 106 is arranged in the intake port 102a on the upstream side of the intake valve 105 and injects fuel into the intake port 102a.
The internal combustion engine 101 may be an in-cylinder direct injection internal combustion engine in which the fuel injection valve 106 directly injects fuel into the combustion chamber 104.

The fuel injected from the fuel injection valve 106 into the intake port 102a is sucked into the combustion chamber 104 together with air via the intake valve 105, and is ignited and burned by spark ignition by the spark plug 107. The combustion pressure generated in the combustion chamber 104 pushes down the piston 108 toward the crankshaft 109 and drives the crankshaft 109 to rotate.
Further, the exhaust valve 110 opens and closes the exhaust port of the combustion chamber 104, and the exhaust valve 110 is opened to discharge the exhaust gas to the exhaust pipe 111.

The catalytic converter 112 provided with a three-way catalyst or the like is installed in the exhaust pipe 111 and purifies the exhaust gas passing through the exhaust pipe 111.
The intake valve 105 opens according to the rotation of the intake cam shaft 115a that is rotationally driven by the crankshaft 109, and the exhaust valve 110 opens during the rotation of the exhaust cam shaft 115b that is rotationally driven by the crankshaft 109. To do.

The variable valve timing device 114 changes the rotational phase angle of the intake camshaft 115a with respect to the crankshaft 109, thereby continuously advancing and retarding the phase (opening timing and closing timing) of the valve operating angle of the intake valve 105. It is a device that changes in the angular direction.
The internal combustion engine 101 may include a variable valve timing device 114 as a device that varies the valve timing of the exhaust valve 110.

As the variable valve timing device 114, a known variable valve timing device such as a hydraulic type or an electric type can be used.
The ignition module 116 is directly attached to each of the spark plugs 107 and supplies ignition energy to the spark plugs 107. The ignition module 116 includes an ignition coil and a power transistor that controls energization of the ignition coil.

The electronic control unit (ECU) 201 includes a microcomputer including a CPU, a RAM, a ROM, an interface and the like.
Then, the electronic control unit 201 inputs signals from various sensors and switches and performs arithmetic processing in accordance with a program stored in advance in the ROM or the like, whereby the fuel injection valve 106, the variable valve timing device 114, and the ignition module 116. The operation amount of various devices such as is calculated and output.

The internal combustion engine 101 includes the intake air amount sensor 103, the crank angle sensor 203 that outputs a crank angle signal CRANK at a predetermined rotation position of the crankshaft 109, and the depression amount of the accelerator pedal 207 (accelerator opening ACC) as the various sensors described above. ) For detecting the accelerator opening, a cam sensor 204 for outputting a cam signal CAM at a predetermined rotational position of the intake cam shaft 115a, a water temperature sensor 208 for detecting the temperature TW of the cooling water of the internal combustion engine 101, and an upstream side of the catalytic converter 112. The exhaust pipe 111 includes an air-fuel ratio sensor 209 that detects the air-fuel ratio AF based on the oxygen concentration in the exhaust gas.
Further, the internal combustion engine 101 includes an engine switch (ignition switch) 205 which is a main switch for operating and stopping, and a signal from the engine switch 205 is input to the electronic control unit 201.

FIG. 2 shows one aspect of the structures of the crank angle sensor 203 and the cam sensor 204.
The crank angle sensor 203 is a shaft supported by the crankshaft 109 and has a signal plate 203b provided with a protrusion 203a as a detected portion around the crankshaft 109, and a protrusion 203a of the signal plate 203b which is fixed to the internal combustion engine 101 side and detects a pulse. Rotation detection device 203c that outputs a crank angle signal CRANK.

The rotation detection device 203c integrally includes a pickup that detects the protrusion 203a and generates a pulse signal, and various processing circuits including a waveform generation circuit and a selection circuit.
As shown in FIG. 3, the rotation detecting device 203c holds a low level as the crank angle signal CRANK when the rotation detecting device 203c does not detect the protrusion 203a, and when the rotation detecting device 203c detects the protrusion 203a. A pulse signal that changes to high level for a certain period of time is output.
However, the rotation detection device 203c holds the high level as the crank angle signal CRANK when the rotation detection device 203c does not detect the protrusion 203a, and keeps the low level for a predetermined time when the rotation detection device 203c detects the protrusion 203a. A pulse signal that changes to a level can be output.

The projections 203a of the signal plate 203b are provided at equal intervals, for example, at a crank angle of 10 deg. However, the two missing projections 203a face each other across the rotation center of the crankshaft 109. It is provided in two places.
Since the protrusion 203a is provided with a missing portion, the crank angle signal CRANK output from the crank angle sensor 203 (rotation detecting device 203c) is, as shown in FIG. 3, every crank angle 10 deg (unit crank angle). After changing to the high level 16 times in succession, the low level is maintained for a crank angle of 30 deg, which corresponds to the angle of the missing portion of the protrusion 203a, and changes to the high level again 16 times in succession.

The first crank angle signal CRANK after the pulse missing period of the crank angle of 30 deg is output at the crank angle of 180 deg, and this crank angle of 180 deg is, in other words, the stroke phase difference between the cylinders in the four-cylinder internal combustion engine 101. For example, it corresponds to the ignition interval.
The crank angle sensor 203 is configured to output the crank angle signal CRANK for each constant crank angle without omission, and outputs a pulse-shaped reference crank angle signal at the reference crank angle position separately from the crank angle sensor 203. A reference crank angle sensor can be provided.

On the other hand, as shown in FIG. 2, the cam sensor 204 is provided with a signal plate 204b pivotally supported on the end of the intake cam shaft 115a and provided with a protrusion 204a as a detected portion around the signal plate 204b and a signal plate 204b fixed on the internal combustion engine 101 side. And a rotation detecting device 204c that detects the protruding portion 204a of the plate 204b and outputs a pulsed cam signal CAM.
The rotation detection device 204c integrally includes a pickup that detects the protrusion 204a and generates a pulse signal, and various processing circuits including a waveform shaping circuit.

The protrusions 204a of the signal plate 204b are provided at only one position, three positions, four positions, and two positions at each of four 90-degree cam angles. The pitch of 204a is set to 30 deg in crank angle and 15 deg in cam angle.
The cam signal CAM, which is a pulse signal output from the cam sensor 204 (rotation detecting device 204c), maintains a low level when the rotation detecting device 204c does not detect the protrusion 204a, as shown in FIG. When the rotation detecting device 204c detects the protrusion 204a, it changes to a high level for a certain period of time, and the cam angle is 90 deg and the crank angle is 180 deg every 180 deg, one alone, three consecutive, four consecutive, and two consecutive. It becomes a pulse signal.

The cam signal CAM is a pulse signal that holds a high level when the rotation detecting device 204c does not detect the protrusion 204a and changes to a low level for a certain period of time when the rotation detecting device 204c detects the protrusion 204a. can do.
Of the cam signals CAM, the single cam signal CAM and the leading signal of the plurality of continuously output cam signals CAM are output at crank angle intervals of 180 deg.

  Here, the continuous output number of the cam signal CAM indicates the number of the cylinder at the specific piston position, and in the four-cylinder internal combustion engine 101, the phase difference in the stroke between the cylinders (ignition interval) is 180 degrees in crank angle. Therefore, it corresponds to the ignition being performed in the order of the first cylinder → the third cylinder → the fourth cylinder → the second cylinder.

That is, the fact that the continuous output number of the cam signal CAM is 1 indicates that the first cylinder is at the specific piston position (before the top dead center TDC), and the continuous output number of the cam signal CAM is 3. Indicates that the third cylinder is in a specific piston position, and that the continuous output number of the cam signal CAM is 4 indicates that the fourth cylinder is in a specific piston position. The fact that the number of continuous outputs of the signal CAM is 2 indicates that the second cylinder is in a specific piston position.
However, the output pattern of the cam signal CAM (the installation pattern of the protrusions 204a) is not limited to the pattern of FIG. 3 (FIG. 2).

The electronic control unit 201 detects the cylinder at the next specific piston position by counting the continuous output number of the cam signal CAM, and selects the cylinder to perform fuel injection or ignition based on the detection result. Set the cylinder that outputs the injection pulse signal and the ignition signal.
More specifically, the electronic control unit 201 detects the tooth missing portion of the crank angle signal CRANK from the cycle of the crank angle signal CRANK, and counts the number of generated cam signals CAM with reference to the tooth missing position. Is set, and the cylinder next reaching a specific piston position is detected based on the number of generated cam signals CAM in this counting section.

Further, the electronic control unit 201 detects the rotational phase of the intake camshaft 115a with respect to the crankshaft 109, calculates a target value (set value) of the rotational phase, and makes the detected value of the rotational phase approach the target value. A function as a control unit for calculating and outputting the operation amount of the variable valve timing device 114 is provided as software.
Specifically, the electronic control unit 201 calculates the target value of the rotation phase based on the engine operating conditions such as the engine speed NE (rpm) calculated based on the crank angle signal CRANK and the engine load TP. The electronic control unit 201 can use, as the engine load TP, the fuel injection amount, the intake air amount, the intake negative pressure, the throttle opening degree, and the like.

Further, the electronic control unit 201 detects the rotation phase of the intake camshaft 115a with respect to the crankshaft 109 based on the crank angle signal CRANK and the cam signal CAM, and the detected value of the rotation phase (actual rotation phase) approaches the target value. Then, feedback control of the rotational phase is performed, in which the operation amount of the actuator of the variable valve timing device 114 is calculated and output.
In the calculation of the operation amount, the electronic control device 201 performs feedback control that changes the operation amount by the PID operation (proportional operation, integral operation, differential operation) based on the deviation (control error) between the detected value of the rotation phase and the target value. In other words, the PID control is performed with the manipulated variable being the sum of the proportional term, the integral term, and the differential term set by the PID control based on the deviation.

For example, when the electronic control device 201 PWM-controls an actuator such as a motor or a solenoid of the variable valve timing device 114, the duty ratio (average applied voltage) is changed by the PID operation as the operation amount.
It should be noted that the control of the actuator of the variable valve timing device 114 is not limited to the PWM control, and therefore the operation amount is not limited to the duty ratio, and the voltage or current can be used as the operation amount.

The electronic control unit 201 detects the rotation phase, for example, as shown in FIG.
That is, the electronic control unit 201 determines the number of crank angle signals CRANK generated between the first crank angle signal CRANK (reference crank angle signal CRANKst) and the cam signal CAM (head cam signal CAM) after the tooth missing period. And the elapsed time from the generation of the latest crank angle signal CRANK is measured, and the time Tcam from the crank angle signal CRANK immediately before the generation of the cam signal CAM to the generation of the cam signal CAM is measured.

  Then, the electronic control unit 201 determines from the reference crank angle signal CRANKst to the crank angle signal CRANK immediately before the cam signal CAM is generated, based on the number of crank angle signals CRANK generated and the output interval angle (10 deg) of the crank angle signal CRANK. The crank angle from the reference crank angle signal CRANKst to the cam signal CAM is calculated by calculating the crank angle, converting the time Tcam to a crank angle based on the engine rotation speed, and adding the crank angles. deg).

Here, the flow of calculation processing of the operation amount of the variable valve timing device 114 by the electronic control unit 201 will be described with reference to the flowcharts of FIGS.
The flowchart of FIG. 5 shows a routine that is interrupted by the electronic control unit 201 when the crank angle signal CRANK is generated.

First, in step S501, the electronic control unit 201 detects the tooth missing period of the crank angle signal CRANK from the generation cycle of the crank angle signal CRANK, so that the first crank angle signal CRANK (reference crank angle signal) after the tooth missing period is detected. CRANKst) is specified.
Next, in step S502, the electronic control unit 201 calculates the engine rotational speed NE (rpm) of the internal combustion engine 101 from the generation cycle of the reference crank angle signal CRANKst, the number of crank angle signals CRANK generated within a predetermined period, and the like. .

Further, the electronic control unit 201 counts the number of occurrences of the crank angle signal CRANK after the reference crank angle signal CRANKst (after the tooth missing period) in step S503.
Further, in step S504, the electronic control unit 201 starts time counting by a timer to measure the elapsed time from the current crank angle signal CRANK, that is, the time Tcam from the crank angle signal CRANK to the generation of the cam signal CAM.

The flowchart of FIG. 6 shows a routine that is interrupted by the electronic control unit 201 when the cam signal CAM (head cam signal CAM) is generated. Since the routine shown in the flowchart of FIG. 6 is interrupted when the cam signal CAM is generated, it is executed at a crank angle cycle of 180 deg, and the execution cycle (ms) varies depending on the engine speed NE. .
First, in step S601, the electronic control unit 201 determines the number of crank angle signals CRANK from the reference crank angle signal CRANKst to the cam signal CAM and the crank angle signal CRANK immediately before the cam signal CAM. Based on the time Tcam until the signal CAM is generated and the engine rotational speed NE, the crank angle from the reference crank angle signal CRANKst to the cam signal CAM is obtained, and the crank angle is calculated with respect to the intake camshaft with respect to the crankshaft 109. The detection value ANG_CAM (actual rotation phase, actual valve timing) of the rotation phase of 115a is set (see FIG. 4).

In this way, the electronic control unit 201 detects the rotational phase detection value ANG_CAM (deg) each time the cam signal CAM (head cam signal CAM) is generated (that is, every 180 degrees of the crank angle). Therefore, the time period in which the electronic control unit 201 updates the rotation phase detection value ANG_CAM changes according to the engine rotation speed NE.
Next, in step S602, the electronic control unit 201 performs processing for the next update of the rotational phase detection value ANG_CAM, such as clearing the count value of the number of crank angle signals CRANK used for calculating the rotational phase detection value ANG_CAM. carry out.

Further, the electronic control unit 201, in step S603, the deviation between the rotational phase detection value ANG_CAM calculated this time and the rotational phase detection value ANG_CAMold calculated when the previous cam signal CAM (head cam signal CAM) was generated, that is, the rotational phase. The amount of change ΔANG_CAM (deg) in the detection cycle (update cycle) of the detection value ANG_CAM is calculated.
The change amount ΔANG_CAM (deg) calculated in step S603 is the change amount in the detection cycle (crank angle 180 deg) of the rotation phase detection value ANG_CAM, and is updated every time the cam signal CAM (head cam signal CAM) is generated. Will be done.
Next, in step S604, the electronic control unit 201 stores the rotational phase detection value ANG_CAM calculated this time as the previous value ANG_CAMold in preparation for the next calculation of the change amount ΔANG_CAM.

The flowchart of FIG. 7 shows a routine that is interrupted by the electronic control unit 201 at a fixed cycle at fixed time intervals (for example, 10 ms).
First, in step S701, the electronic control unit 201 calculates the target value ANG_TAR (target valve timing, target advance value) of the rotational phase according to the engine operating conditions such as the engine rotational speed NE and the engine load.

Next, the electronic control unit 201 proceeds to step S702, and sets the target value ANG_TAR (deg) set in step S701 this time and the previous value ANG_TARold (deg) set in step S701 when the routine was last executed (before a fixed time). Of the target value ANG_TAR in a fixed cycle (setting cycle), ΔANG_TAR (deg) is calculated.
The change amount ΔANG_TAR (deg) is the change amount of the target value ANG_TAR during 10 ms which is the execution cycle of this routine, and is updated each time this routine is executed.

In addition, in step S703, the electronic control unit 201 reads the rotational phase detection value ANG_CAM (the latest value of the rotational phase detection value ANG_CAM) obtained when the immediately preceding cam signal CAM (leading cam signal CAM) was generated.
Further, in step S704, the electronic control unit 201 reads the change amount ΔANG_CAM (the latest value of the change amount ΔANG_CAM) obtained when the immediately preceding cam signal CAM (head cam signal CAM) was generated.

Then, in step S705, the electronic control unit 201 calculates the deviation between the target value ANG_TAR and the rotational phase detection value ANG_CAM as the control deviation (control error) CA.
In the next step S706, the electronic control unit 201 multiplies the control deviation CA by a proportional gain to calculate a proportional term proportional to the control deviation CA, and in proportion to the control deviation CA, the operation amount of the variable valve timing device 114. A proportional operation (proportional control, P control) that changes

Further, in step S707, the electronic control unit 201 multiplies the time integral of the control deviation CA by the integral gain to calculate an integral term proportional to the time integral of the control deviation CA, and is proportional to the time integral of the control deviation CA. Then, the integral operation (integral control, I control) for changing the operation amount of the variable valve timing device 114 is performed.
Further, in step S708, the electronic control unit 201 obtains a deviation between the change amount ΔANG_TAR (deg) of the target value ANG_TAR and the change amount ΔANG_CAM of the rotation phase detection value ANG_CAM, and calculates a value proportional to the deviation as a differential term. Then, the differential operation (differential control, D control) of changing the operation amount of the variable valve timing device 114 in proportion to the differential value of the control deviation CA is performed.

That is, the electronic control unit 201 calculates a deviation between the change amount ΔANG_TAR (deg) of the target value ANG_TAR and the change amount ΔANG_CAM of the rotation phase detection value ANG_CAM as a value corresponding to the differential value of the control deviation CA, and calculates the deviation. The value multiplied by the differential gain (constant) is set as the differential term.
Here, since the change amount ΔANG_CAM is the change amount in the update cycle of the rotation phase detection value ANG_CAM, even if the deviation between the operation timing calculation timing and the rotation phase detection value ANG_CAM update timing changes, the change It is a value that is not affected.

Therefore, even if the deviation between the operation timing calculation timing and the rotation phase detection value ANG_CAM update timing varies, the variation (hunting) of the differential term calculated based on the variation ΔANG_CAM is suppressed, and the variable term causes the variable valve timing. By controlling the device 114, the target value ANG_TAR (target rotation phase) can be stably converged.
After calculating the proportional term, the integral term, and the differential term as described above, the electronic control unit 201 proceeds to step S709 and calculates the sum of these as the final manipulated variable (feedback manipulated variable) to obtain the variable valve timing. Output to the device 114.
By the PID control by the electronic control unit 201, the valve timing of the intake valve 105, which is variable by the variable valve timing unit 114, is controlled to a target value according to the operating state of the internal combustion engine 101.

FIG. 8 is a block diagram showing a differential term calculation function in the operation amount calculation processing by the electronic control unit 201 described according to the flowcharts of FIGS. 5 to 7.
The target value ANG_TAR is calculated every fixed period (10 ms) and input to the first delay circuit 901. The first delay circuit 901 is a circuit that delays the target value ANG_TAR by one cycle (10 ms) of updating the target value ANG_TAR.

Then, the first subtractor 902 outputs the target value ANG_TAR (the latest value of the target value ANG_TAR) bypassing the first delay circuit 901 and the target value ANG_TAR (the previous value of the target value ANG_TAR) via the first delay circuit 901. Input the value and subtract the previous value (the value one cycle before the update) from the latest value of the target value ANG_TAR, in other words, calculate the amount of change ΔANG_TAR in the calculation cycle (10 ms) of the target value ANG_TAR. The processing to be performed is carried out.
On the other hand, the rotational phase detection value ANG_CAM is calculated every time the cam signal CAM is generated (every crank angle of 180 deg), and is input to the second delay circuit 903. The second delay circuit 903 is a circuit that delays the rotation phase detection value ANG_CAM by one cycle of updating the rotation phase detection value ANG_CAM (a period in which the crank angle rotates 180 degrees).

  Then, the second subtractor 904 receives the rotation phase detection value ANG_CAM (the latest value of the rotation phase detection value ANG_CAM) bypassing the second delay circuit 903 and the rotation phase detection value ANG_CAM (rotation phase) via the second delay circuit 903. Detection value ANG_CAM previous value) and subtracting the previous value (the value one cycle before the update) from the latest rotation phase detection value ANG_CAM, in other words, detection of the rotation phase detection value ANG_CAM A process of calculating the change amount ΔANG_CAM in a cycle (between the update cycle and the crank angle of 180 deg) is executed.

The first zero-order hold circuit (0th-order hold circuit) 905 is a circuit which receives the change amount ΔANG_TAR of the target value ANG_TAR output from the first subtractor 902 and holds the input only during the operation amount calculation cycle (10 ms). Is.
The second zero-order hold circuit (0th-order hold circuit) 906 inputs the change amount ΔANG_CAM of the rotation phase detection value ANG_CAM output from the second subtractor 904, and inputs it only during the operation amount calculation cycle (10 ms). Is a circuit for holding.

That is, the second zero-order hold circuit 906 is a circuit for converting the amount of change ΔANG_CAM, which is updated each time the cam signal CAM is generated, into a value that is updated every operation period calculation period (10 ms).
The third subtractor 907 changes the amount of change ΔANG_TAR, which is the output of the first zero-order hold circuit 905, from the amount of change ΔANG_CAM, which is the output of the second zero-order hold circuit 906, for each sampling period of the zero-order hold circuits 905 and 906. Is performed, in other words, a process of calculating a value corresponding to the differential value of the control deviation is performed.
Then, the output of the third subtractor 907 is input to the amplifier circuit 908, and the amplifier circuit 908 performs a process of multiplying the output of the third subtractor 907 by a differential gain, and the calculation result is a differential term (differential operation amount). ) Is output.

Although the contents of the present invention have been specifically described with reference to the preferred embodiments, it is obvious that those skilled in the art can adopt various modifications based on the basic technical idea and teaching of the present invention. is there.
In the above embodiment, the fixed period T1 (ms) for obtaining the change amount ΔANG_TAR of the target value ANG_TAR and the fixed period T2 (ms) for calculating the operation amount are set to the same time, but, for example, T1 <T2 may be set. it can.

Further, the change amount ΔANG_CAM while the internal combustion engine 101 rotates by 180 deg (update period of the rotation phase detection value ANG_CAM) is converted into the change amount during the calculation period (fixed period) of the change amount ΔANG_TAR based on the engine rotation speed. However, the deviation between the converted value and the change amount ΔANG_TAR can be obtained.
Further, the electronic control unit 201 performs the operation of the differential term shown in the functional block diagram of FIG. 8 in the engine speed range in which the variation (hunting) of the differential term is predicted to increase beyond a predetermined value, and Other than that, the differential term can be calculated from the change amount of the control deviation calculated at each operation amount calculation cycle.

Here, the technical idea that can be understood from the above-described embodiment will be described below.
As one aspect thereof, the control device for the variable valve timing device is a control device for a variable valve timing device that varies a rotational phase of a cam shaft with respect to a crank shaft of an internal combustion engine, and outputs at a predetermined rotational position of the crank shaft. A control unit that calculates and outputs an operation amount of the variable valve timing device based on a detected value of the rotational phase obtained from a crank angle signal that is output from the crankshaft and a cam signal that is output at a predetermined rotational position of the cam shaft, The control unit obtains a change amount of the detection value in the rotation phase detection period, and calculates the operation amount based on the change amount.

In a preferred aspect of the control device of the variable valve timing device, the control unit performs the calculation of the manipulated variable at fixed cycles.
In another preferred aspect, the control unit obtains the detected value of the rotational phase and the amount of change in the detected value each time the cam signal is input.

Further, in another preferred aspect, the control unit is configured to calculate and output the operation amount so that the detection value approaches a set value, and the change amount of the detection value of the rotation phase and the fixed period The operation amount is calculated based on the deviation from the change amount of the set value.
Further, in another preferable aspect, the control unit calculates a differential term of PID control based on a deviation between a change amount of the detected value of the rotation phase and a change amount of the set value.

  Further, the control method of the variable valve timing device is, as one aspect thereof, a control method of the variable valve timing device in which a rotational phase of a cam shaft with respect to a crank shaft of an internal combustion engine is variable, and the method is provided at a predetermined rotational position of the crank shaft. Determining a detected value of the rotational phase from a crank angle signal output and a cam signal output at a predetermined rotational position of the cam shaft; and determining a change amount of the detected value in a detection cycle of the rotational phase. Calculating a manipulated variable of the variable valve timing device based on the variation in a fixed cycle.

In a preferred aspect of the control method of the variable valve timing device, the step of calculating the operation amount includes a step of calculating a set value of the rotation phase, and a step of calculating a change amount of the set value in the fixed cycle. Calculating the operation amount based on a deviation between the change amount of the detected value of the rotation phase and the change amount of the set value.
In another preferred aspect, the step of calculating the manipulated variable calculates a differential term of PID control based on a deviation between a change amount of the detected value of the rotation phase and a change amount of the set value.

  101 ... Internal combustion engine, 105 ... Intake valve, 109 ... Crank shaft, 114 ... Variable valve timing device, 115a ... Intake cam shaft, 201 ... Electronic control device, 203 ... Crank angle sensor, 204 ... Cam sensor

Claims (4)

A controller for a variable valve timing device for varying the rotational phase of a cam shaft relative to a crank shaft of an internal combustion engine,
An operation amount of the variable valve timing device is calculated based on a detected value of the rotation phase obtained from a crank angle signal output at a predetermined rotation position of the crank shaft and a cam signal output at a predetermined rotation position of the cam shaft. Equipped with a control unit that calculates and outputs
The control unit is
It is configured to calculate and output the manipulated variable by PID control so that the detected value approaches the set value.
Obtaining the change amount of the detection value in the detection cycle of the rotation phase,
Obtain the amount of change in the set value in a fixed cycle,
A differential term is calculated based on a deviation between the amount of change in the detected value of the rotation phase and the amount of change in the set value.
Control device for variable valve timing device. The control device of the variable valve timing device according to claim 1, wherein the control unit executes the calculation of the differential term for each fixed cycle.   3. The control device for the variable valve timing device according to claim 1, wherein the control unit obtains the detected value of the rotational phase and the amount of change in the detected value every time the cam signal is input. A control method for a variable valve timing device for varying the rotational phase of a camshaft relative to a crankshaft of an internal combustion engine, comprising:
Determining a detected value of the rotation phase from a crank angle signal output at a predetermined rotation position of the crank shaft and a cam signal output at a predetermined rotation position of the cam shaft,
Determining the amount of change in the detection value in the detection cycle of the rotation phase,
Calculating an operation amount of the variable valve timing device based on the change amount for each fixed cycle by PID control ;
Only including,
The step of calculating the operation amount is
Calculating the set value of the rotation phase,
Calculating a change amount of the set value in the fixed cycle;
A step of calculating a differential term based on a deviation between the change amount of the detected value of the rotation phase and the change amount of the set value;
Including, control method for a variable valve timing device.