JP2007278143A - Internal combustion engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine control device preventing overshoot and hunting of cam angle under low temperatures by setting integration renewal value and a renewal condition according to temperature and executing temperature compensation. <P>SOLUTION: The device is provided with a cam angle change means 207 changing a position of a camshaft relative to a crankshaft , a drive means 119 of the cam angle change means 207, a target value calculation means 203 calculating cam angle target value Vt corresponding to an operation condition, a control means 204 operating control amount I of the drive means 114 to make a cam angle detection value consistent with the cam angle target value Vt, and a temperature detection means 118. The control means 204 includes an integration value operation means 205 operating integration value based on phase angle deviation of the cam angle target value Vt and angle detection value, operates control quantity based on the integration value and sets integration renewal value and the renewal condition of the integration value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine controller for controlling valve timing of intake or exhaust of an internal combustion engine.

2. Description of the Related Art Conventionally, an internal combustion engine controller that controls the intake or exhaust valve timing by adjusting the relative phase of a camshaft that rotates in synchronization with a crankshaft is well known.
In this type of internal combustion engine control device, for a predetermined period after the change of the target phase angle of the camshaft, it is prohibited to update the integral value of the phase angle deviation between the target phase angle and the detected phase angle, The cam angle feedback correction amount is calculated based on the calculation process excluding the integral value. The integral value update prohibition period is determined for each rotation speed of the internal combustion engine (see, for example, Patent Document 1 and Patent Document 2).

  However, in the conventional internal combustion engine control devices described in Patent Document 1 and Patent Document 2, when the detected phase angle of the camshaft is toward the target phase angle, the update of the integral value is prohibited, but the cam angle No particular mention is made of a setting method related to the determination value of the cam angle change amount for determining whether or not the angle is toward the target phase angle.

The cam angle driving means (VVT actuator) is operated by the lubricating oil of the internal combustion engine. However, the lower the temperature, the higher the viscosity of the lubricating oil and the lower the fluidity.
Therefore, the dead time from when the target phase angle changes until the detected phase angle actually starts moving increases as the oil temperature decreases, but nevertheless, the conventional device compensates for the temperature. Not done.

  In other words, at the low temperature, the operation determination speed uses the same determination value as after the warm-up of the internal combustion engine, even though the detection phase angle is before or during the operation, and therefore still after the update prohibition period ends. Even if the detected phase angle is before or during operation, overshoot or hunting may occur when the detected phase angle converges to the target phase angle, which may lead to drivability and exhaust gas deterioration. .

  Note that there is no particular problem when the cam angle change control operation is performed only in a warm-up state of the internal combustion engine (a state where the lubricating oil temperature is high and the viscosity is reduced). Due to the fact that the cam angle change control operation has been required even when the oil temperature (the temperature of the internal combustion engine) is a low temperature in the stricter situation, it is caused by the difference in the correlation between the temperature and the cam angle change control operation. The problem is emerging.

JP 2003-65088 A JP-A-11-132164

  In the conventional internal combustion engine control device, even though the dead time until the detected phase angle starts to move after the target phase angle changes varies depending on the temperature, temperature compensation is not performed. The update prohibition period ends within the time range and the integral value is updated, and when the detected phase angle converges to the target phase angle, overshoot and further hunting may occur, leading to deterioration of drivability and exhaust gas There was a problem that there was sex.

  The present invention has been made to solve the above-described problems, and the detected phase angle matches the target phase angle when the target phase angle changes even at low temperatures when the viscosity of the lubricating oil increases. However, when the dead time increases due to the increase in the viscosity of the lubricant and the response change speed of the detected phase angle decreases, the camshaft drive means is still within the dead time and has not started operation. An object of the present invention is to obtain an internal combustion engine control device that prevents an integral value from being updated excessively.

  An internal combustion engine control apparatus according to the present invention includes a camshaft for setting timing of at least one of intake and exhaust of the internal combustion engine, cam angle changing means for changing a relative position of the camshaft with respect to a crankshaft of the internal combustion engine, A crank angle detecting means for generating a crank angle signal corresponding to the rotation angle, a cam angle detecting means attached to a position changed by the cam angle changing means and detecting the cam angle changed by the cam angle changing means; The driving means for driving the cam angle changing means, the target value calculating means for calculating the cam angle target value corresponding to the operating state of the internal combustion engine, and the cam angle detection value from the cam angle detecting means match the cam angle target value. The control means for calculating the control amount of the drive means and the temperature detection means for detecting the temperature of the internal combustion engine as described above, the control means includes a cam angle target value and It includes integral value calculation means that calculates the integral value based on the value related to the phase angle deviation from the detected angle, and calculates the control amount based on the integral value, and the integral update value and update condition of the integral value It is set according to the temperature of the internal combustion engine.

  According to this invention, the control means controls the cam angle detection value by the cam angle detection means so as to coincide with the cam angle target value calculated by the target value calculation means, and the integration calculated by the integral value calculation means. By setting the update value and update condition according to the temperature of the internal combustion engine, excessive update of the integral value before the start of camshaft operation can be avoided, and overshoot and hunting of the cam angle with respect to the cam angle target value can be avoided. It is possible to prevent dribbling and deterioration of exhaust gas.

Embodiment 1 FIG.
The first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a block configuration diagram showing an internal combustion engine control apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a block configuration diagram showing a basic concept of a cam angle control system according to Embodiment 1 of the present invention. It is.

In FIG. 1, an internal combustion engine 101 is provided with an intake pipe 104 having an air cleaner 102 and an air flow sensor 103.
The air cleaner 102 purifies air taken into the internal combustion engine 101 via the intake pipe 104, and the air flow sensor 103 measures the amount of intake air to the internal combustion engine 101.

A throttle valve 105 and an injector 106 are provided in the intake pipe 104.
The throttle valve 105 adjusts the amount of intake air to the internal combustion engine 101, and the injector 106 supplies fuel to the intake air to the internal combustion engine 101 to form an air-fuel mixture.

On the other hand, the internal combustion engine 101 is provided with an exhaust pipe 107 for exhausting exhaust gas after combustion, and the exhaust pipe 107 is provided with an O2 sensor 108 and a three-way catalyst 109.
The O2 sensor 108 measures the amount of remaining air in the exhaust gas discharged from the internal combustion engine 101, and the three-way catalyst 109 converts HC, CO, NOx, which are harmful components of the exhaust gas, into harmless CO2, H2O.

In addition, the internal combustion engine 101 is provided with an intake and exhaust valve that opens and closes a communication portion between the intake pipe 104 and the exhaust pipe 107, an ignition coil 110, and an ignition plug 111.
The ignition coil 110 generates a high voltage on the secondary coil side by interrupting the energization current of the primary coil.
The spark plug 111 generates a spark in the combustion chamber of the internal combustion engine 101 by the high voltage generated from the ignition coil 110.

The camshaft that determines the opening / closing timing of the intake valve is provided with a cam angle sensor (cam angle detection means) 112 that cooperates with the cam angle sensor plate 113.
The cam angle sensor 112 generates a cam angle signal corresponding to the rotational phase of the camshaft.
The cam angle sensor plate 113 is formed integrally with the cam shaft, and a protrusion or a recess for generating a cam angle signal from the cam angle sensor 112 is formed on the outer peripheral portion.

The camshaft is provided with a hydraulic actuator (described later) as a VVT actuator for changing the cam angle.
The hydraulic actuator is driven by an oil control valve (hereinafter abbreviated as “OCV”) 114 that functions as drive means for the hydraulic actuator.
The OCV 114 controls supply and discharge of lubricating oil to the hydraulic actuator, as will be described later.

The camshaft rotates synchronously with the crankshaft of the internal combustion engine 101 at a 1/2 rotation ratio.
Here, the hydraulic actuator for controlling the relative phase of the camshaft with respect to the crankshaft and the OCV 114 are provided on the intake valve side, but may be provided on the exhaust valve side, and further on the intake valve side and the exhaust valve side. You may provide in both.

On the other hand, the crankshaft rotated by the internal combustion engine 101 is provided with a crank angle sensor (crank angle detecting means) 115 that cooperates with the crank angle sensor plate 116.
The crank angle sensor 115 generates a crank angle position signal (hereinafter referred to as “crank angle signal”) corresponding to the rotational position and rotational speed of the internal combustion engine 101.
The crank angle sensor plate 116 is integrally formed with the crankshaft, and a protrusion or a recess for generating a crank angle signal from the crank angle sensor 115 is formed on the outer peripheral portion.

Furthermore, a cooling water 117 for cooling the internal combustion engine 101 and a water temperature sensor (temperature detection means) 118 for detecting the temperature Tw of the cooling water 117 are provided on the outer peripheral portion of the internal combustion engine 101.
The detection signals of the air flow sensor 103, the O2 sensor 108, the cam angle sensor 112, the crank angle sensor 115, and the water temperature sensor 118 are detected together with detection signals of other various sensors (such as a pressure sensor not shown) and an electronic control unit (hereinafter referred to as "ECU" ”).

  The ECU 119 determines the fuel injection amount from the injector 106 and the ignition timing by the spark plug 111 based on detection signals from various sensors (air flow sensor 103, O2 sensor 108, cam angle sensor 112, crank angle sensor 115, water temperature sensor 118, etc.). Are calculated as various drive signals to drive the injector 106, the ignition coil 110, and the like.

In FIG. 2, the ECU 119 includes target value calculation means 203 and control means 204.
The target value calculation means 203 calculates a cam angle target value (target phase angle Vt) based on each detection signal (intake air amount, crank angle signal) from the air flow sensor 103 and the crank angle sensor 115.
The control unit 204 controls various actuators based on the detection signals of the crank angle sensor 115, the cam angle sensor 112, and the water temperature sensor 118 and the cam angle target value (target phase angle Vt) from the target value calculation unit 203. The amount (OCV control current value I) is calculated.

Further, the control unit 204 calculates an integral value Ii (described later) based on a value related to the phase angle deviation ΔV between the target phase angle Vt and the cam angle detection value (detection phase angle Vd). Calculation means 205 is included.
The integral value calculation means 205 calculates an integral value Ii for calculating an OCV control current value I (described later) in accordance with a detection signal (cooling water temperature Tw) of the water temperature sensor 118 corresponding to the temperature of the internal combustion engine 101. .

An OCV (drive means) 114 and a hydraulic actuator (cam angle changing means) 207 are connected to the control means 204.
The OCV 114 feedback-controls the cam angle (relative phase with respect to the crank angle) by driving the hydraulic actuator 207 in response to a drive command from the control means 204 in the ECU 119.

Next, specific operations of the OCV (driving means) 114 and the hydraulic actuator (cam angle changing means) 207 according to the first embodiment of the present invention will be described with reference to FIGS.
3 to 5 are cross-sectional views showing the internal structure of the OCV 114 and the hydraulic actuator (hereinafter simply referred to as “actuator”) 207.

FIG. 3 shows a case where the drive current for the OCV 114 is 0 [A], and the relative cam angle phase is the maximum retarded side with respect to the rotational direction of the camshaft synchronized with the crankshaft (see solid line arrow). The controlled state is shown (see broken line arrows).
FIG. 4 shows a case where the drive current for the OCV 114 is about 0.5 [A], and shows a state where the phase of the relative cam angle is controlled to the intermediate position with respect to the rotation direction (see the solid line arrow). ing.

FIG. 5 shows a case where the drive current for the OCV 114 is 1 [A], and the relative cam angle phase with respect to the rotational direction (see the solid line arrow) is the maximum advance angle side (see the broken line arrow). Shows the controlled state.
That is, the state of the actuator 207 that is hydraulically driven according to the energization current to the OCV 114 is shown in association with the flow direction of the lubricating oil (see the vertical arrow).

3 to 5, the actuator 207 includes a rotor 402, a housing 403, a retard hydraulic chamber 404, and an advance hydraulic chamber 405.
The housing 403 is provided with a retard passage 406 that communicates with the retard hydraulic chamber 404 and an advance passage 407 that communicates with the advance hydraulic chamber 405.

On the other hand, the OCV 114 includes a coil 409, a spool 410, a housing 411, and a spring 412.
The OCV 114 is connected to the actuator 207 via the retard passage 406 and the advance passage 407.
The OCV 114 is connected to an oil pump (not shown) that supplies lubricating oil.

The rotor 402 of the actuator 207 is fastened to the camshaft of the internal combustion engine 101 via a bolt and rotates integrally with the camshaft.
A sprocket (or pulley) is fastened to the housing 403, and a chain (or belt) engaged with a crankshaft is engaged with the sprocket (or pulley).

As a result, the rotational power of the crankshaft is transmitted to the sprocket (or pulley) via the chain (or belt), so that the housing 403 rotates in synchronization with the crankshaft.
Here, the gear ratio between the sprocket (or pulley) of the crankshaft and the sprocket (or pulley) fastened to the housing 403 is 1: 2, and the camshaft has a crankshaft as described above. Is rotated by 1/2 and transmitted.

Lubricating oil of the internal combustion engine 101 is supplied or discharged to the retarded hydraulic chamber 404 and the advanced hydraulic chamber 405 of the actuator 207 via the OCV 114.
As a result, the positional relationship of the rotor 402 integral with the camshaft is changed relative to the housing 403 that rotates synchronously with the crankshaft.
That is, the rotational position of the camshaft changes relative to the crankshaft.

At this time, as shown in FIGS. 3 to 5, the OCV 114 controls the supply and discharge of the lubricating oil to the retard hydraulic chamber 404 and the advance hydraulic chamber 405.
That is, the direction and amount of the lubricating oil flow are controlled by controlling the energization of the coil 409 to change the position of the spool 410 and changing the positional relationship between the groove provided in the housing 411 and the unevenness of the spool 410. .

First, FIG. 3 shows a state in which lubricating oil is supplied to the retarded hydraulic chamber 404 of the actuator 207.
At this time, no drive current flows through the coil 409 of the OCV 114 (current value = 0 [A]), and the spool 410 is urged leftward in the drawing by the spring 412.
Therefore, the lubricating oil (see the upward arrow in FIG. 3) supplied from the oil pump through the lower central groove of the housing 411 passes through the retard passage 406 and enters the retard hydraulic chamber 404 of the actuator 207. Supplied.

At the same time, the lubricating oil in the advance hydraulic chamber 405 (see the downward arrow in FIG. 3) is discharged to the outside through the advance passage 407.
As a result, the rotor 402 of the actuator 207 is rotated counterclockwise (that is, retarded) relative to the housing 403, as indicated by a broken line arrow in FIG.

FIG. 4 shows a state in which both the retard passage 406 and the advance passage 407 to the retard hydraulic chamber 404 and the advance hydraulic chamber 405 in the actuator 207 are closed.
At this time, a current of about 0.5 [A] flows through the coil 409 of the OCV 114, and the exciting force generated by the coil 409 and the biasing force of the spring 412 are balanced.

Therefore, as shown in FIG. 4, the spool 410 is adjusted to a position where both the retard passage 406 and the advance passage 407 are blocked, and the lubricating oil from the oil pump is supplied to the retard hydraulic chamber 404 and the advance hydraulic chamber. No lubricating oil in the retard hydraulic chamber 404 and the advanced hydraulic chamber 405 will flow out of either of the 405 and the advanced hydraulic chamber 404.
As a result, the relative position between the rotor 402 and the housing 403 is held at the predetermined position shown in FIG.

Further, FIG. 5 shows a case where lubricating oil is supplied to the advance hydraulic chamber 405 of the actuator 207.
At this time, a current of 1 [A] flows through the coil 409 of the OCV 114, and the spool 410 moves to the right in the figure by overcoming the biasing force of the spring 412.
Accordingly, the lubricating oil (see the upward arrow in FIG. 5) supplied from the oil pump is supplied to the advance hydraulic chamber 405 through the advance passage 407.

At the same time, the lubricating oil (see the downward arrow in FIG. 5) in the retard hydraulic chamber 404 is discharged to the outside through the retard passage 406.
As a result, the rotor 402 of the actuator 207 is rotated clockwise (that is, advanced) relative to the housing 403 as indicated by a broken line arrow in FIG.

FIG. 6 is a timing chart showing the crank angle signal and the cam angle signal, and shows each pulse waveform output from the crank angle sensor 115 and the cam angle sensor 112.
Here, a cylinder identification process and a cam angle (detection phase angle) detection process of the internal combustion engine 101 will be described.

As shown in FIG. 6, the crank angle sensor 115 outputs a pulse signal every 10 degrees of the crank angle. However, a missing tooth that does not output a pulse signal at the position of B95 (BTDC 95 degrees) or B105 (BTDC 105 degrees). A part is provided.
The cam angle sensor 112 generates a detection signal at the timing of B100 and B135 when the cam angle is the most retarded angle.

  The crank angle signal (detection signal of the crank angle sensor 115) is provided with a missing tooth portion, so that it is possible to grasp at which crank position each signal every 10 degrees is located.

For example, every time a crank angle signal is input, the count value of the free run counter is acquired, the time (cycle) between each pulse of the crank angle signal is measured, and if the cycle is longer than usual, the missing tooth It can be recognized that it is the next tooth (B85) of the part.
Furthermore, even if the period is different between the case of missing one tooth and the case of missing two teeth, it is possible to distinguish between the one missing tooth portion and the two missing tooth portion. Thus, cylinder identification is also possible.

  In this way, the missing tooth position of the crank angle signal can be specified, so that the current crank angle signal is grasped at which crank angle position by sequentially counting each time the crank angle signal is inputted. be able to.

Next, the detection process of the cam angle detection phase angle Vd will be described.
This detection process is executed in the detection process of the detection phase angle Vd in step 502 in FIG. 7 described later.

  Even when the cam angle signal is input, a free-run counter value used for measuring the input time Tcrk of the crank angle signal is acquired, and the crank angle Acrk [degCA] immediately after the input of the cam angle signal and the input of the cam angle signal are acquired. Using the time Tcam and the time of the crank angle signal before and after the input of the cam angle signal, the cam angle Acam [degCA] can be calculated as in the following equation (1).

  Acam = Acrk + {(Tcrk−Tcam) / (Tcrk−Tcrk [i−1])} × ΔAcrk (1)

However, in Expression (1), Tcrk [i−1] is the input time (previous value) of the crank angle signal, and ΔAcrk is the crank angle [degCA] between the crank angle signals.
In the most retarded angle state, the cam angle Acam detected by the equation (1) is separately learned, and the change from the most retarded angle position that is the reference position, that is, the advance, based on the angle difference between the learned value and the current detected value. The angular amount is detected as a detection phase angle Vd.

FIG. 7 is a flowchart showing cam angle control calculation processing, and shows a processing procedure executed by the microprocessor (target value calculation means 203 and control means 204) in the ECU 119.
The processing routine of FIG. 7 is executed for each timing input of B75 of the crank angle signal, for example.

In FIG. 7, first, the target value calculation unit 203 executes a calculation process of the target phase angle Vt (step 501).
Specifically, the rotational speed of the internal combustion engine 101 is calculated based on the cycle time between pulses of the crank angle signal obtained from the crank angle sensor 115 at every predetermined timing, and the internal combustion engine obtained from the rotational speed and the airflow sensor 103 is calculated. The target phase preliminarily stored in the ROM (not shown) in the ECU 119 is calculated by calculating the charging efficiency based on the intake air amount of 101 and interpolating a two-dimensional map using the rotational speed and the charging efficiency. The angle Vt is calculated.

Subsequently, as described above, the control unit 204 performs a calculation process of the detection phase angle Vd (step 502).
Next, the difference between the target phase angle Vt and the detected phase angle Vd is calculated as a phase angle deviation ΔV (step 503), and it is determined whether or not the target phase angle Vt is equal to or greater than the most retarded angle control determination value KVr. (Step 504).

Here, the most retarded angle control determination value KVr is set to about 2 [degCA] so as to exclude, for example, a region where the detected phase angle Vd is not stable when controlled near the most retarded angle position.
If it is determined in step 504 that Vt <KVr (that is, NO), the OCV control current value I is set to “0” (step 505), and the process proceeds to final control signal output processing (step 517).

On the other hand, if it is determined in step 504 that Vt ≧ KVr (that is, YES), it is determined whether or not the absolute value | ΔV | of the phase angle deviation is equal to or smaller than the holding control determination value KVh (step 506).
Here, the holding control determination value KVh is set to about 1 [degCA] so that the generated torque of the internal combustion engine 101 does not fluctuate due to fluctuations in the cam angle, for example.

  If it is determined in step 506 that | ΔV | ≦ KVh (that is, YES), the integral update waiting timer Th is cleared to “0” (step 507), and the phase angle deviation ΔV and the integral gain are added to the integral value Ii. A value (= Ii + ΔV × Gi) obtained by adding the multiplication value with Gi is calculated (updated setting) as a new integrated value Ii (step 508).

Further, the holding current learning value Ih and the updated integrated value Ii are added to calculate the OCV control current value I (= Ih + Ii) (step 509), and the process proceeds to the control signal output process (step 517).
Here, the holding current learning value Ih is the OCV control current value I in a state where the detected phase angle Vd is substantially equal to the target phase angle Vt and stabilized in a separate processing routine as the holding current learning value Ih. Assume that you have learned in advance.

On the other hand, if it is determined in step 506 that | ΔV |> KVh (that is, NO), a time deviation ΔTf (= Tf−Tf [i−1) obtained by subtracting the previous time Tf [i−1] from the current time Tf. ] Is added to the integral update waiting timer Th to calculate (update setting) a new value (= Th + ΔTf) of the integral update waiting timer Th (step 510).
Here, as the current time Tf, the value of the free-run counter at the time when this process is started is acquired in advance. The previous time Tf [i−1] is the time (free run counter value) when the processing routine of FIG. 7 was started last time.

Since the processing routine of FIG. 7 is executed at every predetermined input timing of the crank angle signal, the processing cycle changes depending on the rotation speed of the internal combustion engine 101. Therefore, the elapsed time is obtained from the time when the processing is started. Is calculated.
However, if the processing routine of FIG. 7 is executed by time management, such as being executed every predetermined cycle (for example, 25 [ms]), the calculation cycle is added to the integral update waiting timer Th. May be.

Next, following step 510, the integral update standby timer Th and the standby time determination value Kt are compared to determine whether or not the integral update standby timer Th has exceeded the standby time determination value Kt (step 511).
The setting process of the standby time determination value Kt will be described later.

  If it is determined in step 511 that Th> Kt (that is, YES), the value obtained by dividing the phase angle change amount ΔVd of the detected phase angle Vd by the elapsed time ΔTf, that is, the phase angle change amount per unit time (= ΔVd / It is determined whether (ΔTf) is smaller than the change amount determination value KVs (step 512).

Here, the phase angle change amount ΔVd is calculated as a deviation (= Vd−Vd [i−1]) between the current detected phase angle Vd and the previous detected phase angle Vd [i−1].
Further, as described above, the elapsed time ΔTf is calculated as a time deviation (= Tf−Tf [i−1]) between the current time Tf and the previous time Tf [i−1].

If it is determined in step 512 that ΔVd / ΔTf <KVs (ie, YES), the detected phase angle Vd has changed despite the presence of the phase angle deviation ΔV between the detected phase angle Vd and the target phase angle Vt. As in step 508 described above, the value obtained by adding the product of the phase angle deviation ΔV and the integral gain Gi to the integral value Ii (= Ii + ΔV × Gi) is used as the new integral value. It is calculated (update setting) as Ii (step 513), and the process proceeds to the proportional value Ip calculation process (step 514).
The setting process of the integral gain Gi will be described later.

On the other hand, if it is determined in step 512 that ΔVd / ΔTf ≧ KVs (ie, NO), it is considered that the detected phase angle Vd is changing although the phase angle deviation ΔV is present. The process proceeds to step 514 without executing the process.
In this case, since the update process (step 513) of the integral value Ii is not executed, the previous value is held.

Subsequently, the phase angle deviation ΔV is multiplied by the proportional gain Gp to calculate a proportional value Ip (step 514), and the current phase angle deviation ΔV and the previous phase angle deviation ΔV [i−1] (= ΔV−ΔV [i−1]) is multiplied by the differential gain Gd to calculate a differential value Id (step 515).
Further, the OCV control current value I is calculated by adding the holding current learning value Ih, the integral value Ii, the proportional value Ip, and the differential value Id (step 516), and the process proceeds to the control signal output process (step 517).

  Finally, in step 517, the OCV control current value I is subjected to temperature compensation processing, etc., converted to a driving duty value of the OCV 114, and further converted to an ON / OFF signal that matches the driving duty value. Is output to the OCV 114, and the processing routine of FIG.

Here, the setting process of the standby time determination value Kt used in step 511 will be described.
As described above, the delay time from when the target phase angle Vt changes until the detected phase angle Vd actually starts to change is the viscosity (temperature) of the lubricating oil used to advance and retard the cam angle. ).
That is, at a low temperature, the lubricating oil becomes highly viscous and the flow becomes slow, so the delay time increases. On the other hand, at a high temperature, the lubricating oil has a low viscosity and the flow is fast, so the delay time is reduced.

Therefore, it is desirable that the standby time determination value Kt is set to a time corresponding to the delay time.
This is because, for example, the detected phase angle Vd does not change even after the dead time elapses even though the target phase angle Vt has changed, because the OCV control current value I only changes the detected phase angle Vd. This is because it is necessary to update the integrated value Ii and change the OCV control current value I in this case.
Conversely, if the integral value Ii update process (step 513) is executed before the lapse of the delay time, overshoot occurs due to unnecessary update of the integral value Ii when the detected phase angle Vd converges to the target phase angle Vt. This is because.

Specifically, the standby time determination value Kt used in step 511 is set using a map value (see FIG. 8) stored in advance in the ROM in the ECU 119.
In FIG. 8, the standby time determination value Kt is set for each temperature of the internal combustion engine 101 (water temperature Tw detected by the water temperature sensor 118), and is set to a large value on the low water temperature side, and on the high water temperature side. Set to a small value.

Thus, based on the water temperature Tw detected during the operation of the internal combustion engine 101, the standby time determination value Kt is set with reference to the map shown in FIG.
That is, since the lubricating oil becomes highly viscous and the delay time increases at low temperatures, the standby time determination value Kt becomes a large value on the low water temperature side according to the map value for each water temperature Tw (see FIG. 8). It is set to a small value on the high water temperature side.
Instead of the water temperature Tw, the standby time determination value Kt is set using a value obtained by estimating the oil temperature from the operation information of the internal combustion engine 101 detected by other various sensors or a value obtained by directly detecting the lubricating oil temperature. May be.

Next, referring to the timing charts of FIG. 9 and FIG. 10, operations related to the above steps 511 and 512 according to the first embodiment of the present invention will be described.
9 and 10, each operation of the camshaft phase angle and the integral value Ii is shown in association with the standby time determination value Kt.

FIG. 9 shows each operation example at high temperature (when the viscosity of the lubricating oil is low and the operation is fast), and FIG. 10 shows each operation example at low temperature (when the viscosity of the lubricating oil is high and the operation is slow).
In the phase angle [degCA], the operation at the target phase angle Vt is indicated by a broken line, and the operation at the detection phase angle Vd is indicated by a solid line.

In FIG. 9, the detected phase angle Vd when the lubricating oil is at a high temperature (that is, when the internal combustion engine 101 is warmed up) quickly follows the change in the target phase angle Vt.
In FIG. 9, for example, when the driver performs an accelerator operation, the target phase angle changes at time A, and the detected phase angle Vd starts to change at time B after a predetermined delay time has elapsed from time A.

  At this time, since the standby time determination value Kt is set to a time longer than the period from time A to time B, the standby time determination value Kt elapses after the target phase angle Vt changes. The integral value Ii is not updated.

Thereafter, at the time C when the standby time determination value Kt has elapsed from the time A at which the target phase angle Vt has changed, the detection phase angle Vd has already changed, and the amount of change per unit time is greater than or equal to the change amount determination value KVs. Since it has reached, the integral value Ii is not updated.
Therefore, at the subsequent time D, the detected phase angle Vd converges to the target phase angle Vt without causing overshoot or the like.

On the other hand, in FIG. 10, the detected phase angle Vd when the lubricating oil is at a low temperature (that is, the state where the internal combustion engine 101 has not been warmed up) is greater than the case of FIG. 9 with respect to the change in the target phase angle Vt. Follow slowly.
Here, first, the operation when the standby time determination value Kt is assumed to be a fixed value and set to the same value as at high temperatures (see FIG. 9) will be described.

In FIG. 10, an alternate long and short dash line indicates the operation of the detected phase angle Vd and the integral value Ii when the standby time determination value Kt is set to a fixed value without being set to a value corresponding to the temperature.
In this case, when the target phase angle Vt changes at time A, the detected phase angle Vd starts to change at time B ′, which is later than time B when the lubricating oil is hot (FIG. 9).

At this time, if the standby time determination value Kt is set to the same setting value (see the one-dot chain line) as in the case of the high temperature (FIG. 9) even when the lubricating oil temperature is low, the detection phase is still detected at the subsequent time C. Since the angle Vd is not operating, the integral value Ii starts to be updated on the increase side as indicated by the one-dot chain line.
Thereafter, at time B ′, the detection phase angle Vd finally starts to operate, and at the subsequent time C ′, the change amount per unit time of the detection phase angle Vd becomes equal to or greater than the change amount determination value KVs, and the integration value Ii is updated. Stop.

Further, at time D in FIG. 10, the detection phase angle Vd reaches the target phase angle Vt, but the integrated value Ii is updated and held as it is during the period from time C to time C ′, so that the detection phase angle Overshoot occurs when the angle Vd (see the dashed line) exceeds the target phase angle Vt.
Furthermore, at time E after the occurrence of overshoot, the detected phase angle finally converges to the target phase angle by correcting the decrease in the integral value Ii.

Next, the operation according to the first embodiment of the present invention will be described with reference to the solid line in FIG.
The solid line in FIG. 10 indicates that the standby time determination value Kt is variably set as described above (see FIG. 8) according to the temperature (water temperature Tw), and the standby time determination value Kt at a low temperature is larger than that at a high temperature. The operation of the detected phase angle Vd and the integral value Ii when changed to is shown.

  In this case, the standby time determination value Kt (period in which the update of the integral value Ii is stopped) is longer than the period from time A when the target phase angle Vt changes to time B ′ when the detected phase angle Vd starts to change. Since the long period is set, the update of the integral value Ii is not started even if the detection phase angle Vd is not operating at the time C.

That is, the integral value Ii can be updated from the time after the period of the standby time determination value Kt has elapsed since the target phase angle Vt changed at time A.
At the time after the elapse of the standby time determination value Kt, the detection phase angle Vd operates with a change amount equal to or greater than the change amount determination value KVs. Therefore, the update process of the integral value Ii is not executed, and the detection phase angle Vd is Overshoot does not occur at time D ′ when it converges to the target phase angle Vt.

As described above, the standby time determination value Kt corresponding to the standby state of the update process of the integral value Ii after the target phase angle Vt is changed is changed according to the temperature of the internal combustion engine 101 (water temperature Tw). By setting the longer as the water temperature is lower, the integrated value is obtained even when the delay time from when the target phase angle Vt changes until the detected phase angle Vd starts to change at a low temperature of the internal combustion engine 101 is increased. Ii is not updated unnecessarily, and when the detected phase angle Vd converges to the target phase angle Vt, occurrence of overshoot and hunting can be prevented, and deterioration of drivability can be prevented.
Further, since the water temperature sensor 118 is used as the temperature detecting means, the temperature information of the internal combustion engine 101 can be acquired without adding a sensor.

Next, the operation related to step 513 will be described with reference to FIG.
As described above, the cam angle change rate becomes slower at low oil temperature (that is, when the viscosity is high), and conversely, it increases at high oil temperature (that is, when the viscosity is low).
Therefore, if the integral gain Gi is larger than the appropriate value at low temperatures, the response speed is slow (the delay time is large), so overcorrection occurs, and overshoot occurs when the detected phase angle Vd converges to the target phase angle Vt. In some cases, it may cause hunting.

Therefore, in step 513 in FIG. 7, the integral gain Gi is set with reference to the map value in FIG. 11 based on the water temperature Tw detected during operation. The map value in FIG. 11 is set for each water temperature Tw and is stored in advance in the ROM in the ECU 119.
In FIG. 11, the map value of the integral gain Gi is a small set value on the low water temperature side and a large set value on the high water temperature side.

  As described above, the integral gain Gi is changed in accordance with the response time and delay time of the detected phase angle Vd that changes depending on the temperature of the internal combustion engine 101, and particularly at low temperatures, the integral gain Gi is set to a small value. Shooting and hunting can be prevented, and dribble deterioration can be prevented.

Next, the change amount determination value KVs setting process in step 512 will be described with reference to FIG.
Normally, in order to increase the cam angle response speed and prioritize the operation output performance of the internal combustion engine 101 at high temperatures, the proportional gain Gp and the differential gain Gd are adapted to increase the cam angle response speed. Yes.
Therefore, even if the change amount determination value KVs of the detection phase angle Vd for executing the integral control is set to a small value to some extent, the detection phase angle Vd converges to the target phase angle Vt by the proportional differential (PD) control. Control is never executed.

  Even at high temperatures, if the in-vehicle battery is removed and the holding current learning value Ih is reset, the OCV control current value I actually holds the detected phase angle Vd at the target phase angle Vt. Therefore, there is a possibility that the operation of the detection phase angle Vd becomes slower than usual, or the detection phase angle Vd does not converge to the target phase angle Vt and stops midway.

  Therefore, when the holding current learning value Ih is reset, the integrated value Ii is updated to converge the detection phase angle Vd to the target phase angle Vt, but the detection phase angle Vd is set to the target phase angle Vt as quickly as possible. In order to converge and to quickly execute the learning process of the holding current learning value Ih, it is necessary to set the variation determination value KVs in step 512 as small as possible.

  However, when the proportional gain Gp and the differential gain Gd at high temperature are used at low temperature, the response speed of the cam angle is lower than at high temperature, so from the determination result based on the variation determination value KVs at high temperature, The integrated value Ii is updated even though the holding current learning value Ih is correctly learned, and there is a possibility that overshoot occurs when the detected phase angle Vd converges to the target phase angle Vt.

Therefore, in step 512 in FIG. 7, the change amount determination value KVs is set with reference to the map value in FIG. 12 based on the water temperature Tw detected during operation. The map value in FIG. 12 is set for each water temperature Tw and is stored in advance in the ROM in the ECU 119.
In FIG. 12, the map value of the variation determination value KVs is a large set value on the low water temperature side and a small set value on the high water temperature side.

  As shown in FIG. 12, the change amount determination value KVs is a map value corresponding to the water temperature Tw when the temperature is lower than the high temperature (under the condition where the response speed of the detection phase angle Vd is fast) (under the condition where the response speed is slow). Is set to a larger value.

  As described above, the control means 204 according to the first embodiment of the present invention controls the detection phase angle (cam angle detection value) Vd so as to coincide with the target phase angle (cam angle target value) Vt, and also integrates the integrated value. The integral update value and update condition of the integral value Ii calculated by the calculation means 205 are set according to the temperature of the internal combustion engine 101.

  As a result, even if the responsiveness of the detected phase angle Vd decreases due to an increase in the viscosity of the lubricating oil at low oil temperature, the integrated value Ii is not updated when the detected phase angle Vd is operating. Overshoot does not occur when the angle Vd converges to the target phase angle Vt, and drivability deterioration can be prevented.

Embodiment 2. FIG.
In the first embodiment, only the integral update process is skipped based on the change amount determination value KVs of the detected phase angle Vd and the number of integral update skips is not considered. However, as shown in FIG. The integration update process may be executed when the update skip count SKIP reaches the predetermined count Ks.

FIG. 13 is a flowchart showing cam angle control calculation processing according to the second embodiment of the present invention. Steps 501 to 517 are the same as those described above (see FIG. 7), and thus detailed description thereof is omitted here.
13 is different from FIG. 7 only in that a determination process, a setting process, and a decrement process (steps 601 to 603) relating to the integral update skip count SKIP including a down counter are inserted after step 512.

In step 511 in FIG. 13, it is determined that the integral update standby timer Th is larger than the standby time determination value Kt (that is, YES), and in step 512, the phase angle change amount per unit time (= ΔVd / ΔTf). Is determined to be smaller than the change amount determination value KVs (that is, YES), it is first determined whether or not the integral update skip count SKIP is “0” (step 601).
Note that the initial value of the integral update skip count SKIP is set to a predetermined count Ks in advance.

For example, if the integral update prohibition process has already reached the predetermined number of times Ks and it is determined in step 601 that SKIP = 0 (that is, YES), the process proceeds to step 513, where the integral value Ii is updated.
Subsequently, the predetermined number Ks is set in the integral update skip count SKIP (step 602), and the process proceeds to the proportional value Ip setting process (step 514).

  On the other hand, if it is determined in step 601 that SKIP> 0 (that is, NO), “1” is subtracted from the integral update skip count SKIP to execute a decrement process (step 603), and then the process proceeds to step 514.

As shown in FIG. 14, the predetermined number of times Ks refers to a map value corresponding to the water temperature Tw, and is lower than the high temperature (under the condition that the response speed of the detection phase angle Vd is fast) (the response speed is slow). (Condition) is set to a larger value.
At this time, as the value of the predetermined number of times Ks is larger, the update cycle of the integral value Ii is longer. Therefore, setting the larger predetermined number of times Ks as the temperature is lower as shown in FIG. 14 is that the integral gain Gi is reduced. Has the same effect.

  Therefore, as shown in FIG. 14, by setting the integral update skip count SKIP to be larger as the temperature is lower, the update period of the integral value Ii in step 513 in FIG. 13 becomes longer, and overshoot and hunting occur at low water temperature. It is possible to prevent the deterioration of drabbilities.

In the second embodiment, the integral update skip count SKIP is used as a down counter, and “1” is subtracted from the integral update skip count SKIP in the decrement process (step 603). However, the integral update skip count SKIP is configured by a timer. May be.
In this case, in step 602, a predetermined time is set as the integral update skip count SKIP, and in the decrement process in step 603, the integral update skip count SKIP updates the elapsed time ΔTf (= Tf−Tf [i−1]). As time, subtraction update is performed as in the following equation (2).

  SKIP (current value) = SKIP (previous value) −ΔTf (2)

  However, in Expression (2), since the multiple of the update time ΔTf with respect to the integral update skip count SKIP does not necessarily match the predetermined count Ks, it is determined whether or not “SKIP = 0” in step 601 above. Instead, it is necessary to determine whether or not “SKIP ≦ 0”.

1 is a block configuration diagram showing an internal combustion engine control apparatus according to Embodiment 1 of the present invention. FIG. It is a block block diagram which shows the basic concept of the cam angle control system which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the internal structure of OCV and hydraulic actuator which are used for Embodiment 1 of this invention, and has shown the cam angle position of the most retarded angle state. It is sectional drawing which shows the internal structure of OCV and the hydraulic actuator used for Embodiment 1 of this invention, and has shown the intermediate cam angle position. It is sectional drawing which shows the internal structure of OCV and hydraulic actuator which are used for Embodiment 1 of this invention, and has shown the cam angle position of the most advanced angle state. It is a timing chart which shows the crank angle signal and cam angle signal in Embodiment 1 of this invention. It is a flowchart which shows the control calculation process of the cam angle by Embodiment 1 of this invention. It is explanatory drawing which shows the map value of the waiting time determination value set according to temperature by Embodiment 1 of this invention. It is a timing chart for demonstrating the operation | movement at the time of the high temperature by Embodiment 1 of this invention. It is a timing chart for demonstrating the operation | movement at the time of the low temperature by Embodiment 1 of this invention. It is explanatory drawing which shows the map value of the integral gain set according to temperature by Embodiment 1 of this invention. It is explanatory drawing which shows the map value of the variation | change_quantity determination value set according to temperature by Embodiment 1 of this invention. It is a flowchart which shows the control calculation process of the cam angle by Embodiment 2 of this invention. It is explanatory drawing which shows the map value of the integral update skip frequency | count set according to temperature by Embodiment 2 of this invention.

Explanation of symbols

  101 internal combustion engine, 104 intake pipe, 107 exhaust pipe, 112 cam angle sensor (cam angle detection means), 114 OCV (drive means), 115 crank angle sensor (crank angle detection means), 118 water temperature sensor (temperature detection means), 119 ECU, 203 target value calculation means, 204 control means, 205 integral value calculation means, 207 hydraulic actuator (cam angle changing means), Gi integral gain, Ii integral value, Kt waiting time judgment value, Th integral update waiting timer, Tw Water temperature, Vd detection phase angle (cam angle detection value), Vt target phase angle (cam angle target value), ΔV phase angle deviation, ΔVd phase angle change amount.

Claims (9)

A camshaft for setting the timing of at least one of intake and exhaust of the internal combustion engine;
Cam angle changing means for changing the relative position of the camshaft with respect to the crankshaft of the internal combustion engine;
Crank angle detection means for generating a crank angle signal corresponding to the rotation angle of the crankshaft;
A cam angle detecting means attached to a position changed by the cam angle changing means and detecting the cam angle changed by the cam angle changing means;
Driving means for driving the cam angle changing means;
Target value calculating means for calculating a cam angle target value according to the operating state of the internal combustion engine;
Control means for calculating a control amount of the drive means so that a cam angle detection value from the cam angle detection means matches the cam angle target value;
Temperature detecting means for detecting the temperature of the internal combustion engine,
The control means includes
An integral value calculating means for calculating an integral value based on a value related to a phase angle deviation between the cam angle target value and the cam angle detection value;
While calculating the control amount based on the integral value,
An internal combustion engine control apparatus, wherein an integral update value and an update condition of the integral value are set according to a temperature of the internal combustion engine. The control means includes
A dead time integral update stop means for setting an integral update stop period for stopping the update of the integral value when the cam angle target value changes by a predetermined value or more;
The internal combustion engine control device according to claim 1, wherein the integral update stop period is set according to a temperature of the internal combustion engine.   The internal combustion engine control device according to claim 2, wherein the control means sets the integral update stop period to a longer period as the temperature of the internal combustion engine is lower. The control means includes
An integral update stop means for stopping update of the integral value when the change amount of the cam angle detection value is less than a predetermined value;
The internal combustion engine control device according to claim 1, wherein the predetermined value is set according to a temperature of the internal combustion engine.   The internal combustion engine control device according to claim 4, wherein the control means sets the predetermined value to a smaller value as the temperature of the internal combustion engine is lower.   The internal combustion engine control device according to claim 1, wherein the control means changes the integral update value based on a temperature of the internal combustion engine.   The internal combustion engine control device according to claim 6, wherein the control means sets the integral update value to a smaller value as the temperature of the internal combustion engine is lower.   The internal combustion engine control device according to claim 1, wherein the control unit sets an update period of the integral update value according to a temperature of the internal combustion engine.   The internal combustion engine control device according to claim 8, wherein the control means sets the update cycle to a longer cycle as the temperature of the internal combustion engine is lower.

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