JP2002054465A - Device and method for controlling valve timing of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure responsiveness of a control means without sacrificing responsiveness of other valve timing control means even when a plurality of valve timing control means are operated. SOLUTION: A valve timing control device comprises a first valve (an intake valve V1) to open and close an intake pipe 2 and an exhaust pipe 3, communicating with the combustion chamber of an internal combustion engine 1; and first and second valve timing control means to vary a valve timing by controlling a control value so that the actual timing advance positions of the first and second valves coincide with target timing advance positions. A control valve for the first valve timing control means is varied by the control state of a second valve timing control means and responsiveness during operation of two valve timing control means is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for an internal combustion engine that controls valve timings of intake and exhaust of the internal combustion engine.

[0002]

2. Description of the Related Art FIG. 18 is a block diagram showing a conventional valve characteristic control device for an internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 9-317504. This device comprises a combustion chamber M of an internal combustion engine M1.
Intake valve M for opening and closing the intake passage M3 leading to
4, an exhaust valve M7 for opening and closing an exhaust passage M6 communicating with the combustion chamber M2, a first operating mechanism M5 and a first operating mechanism M5 for changing valve characteristics of the intake valve M4 and the exhaust valve M7 by being driven by fluid pressure. Operation mechanism M8 of 2
A fluid supply source M10 for supplying a fluid to the two operation mechanisms M5 and M8 via the fluid passage M9, and a fluid amount supplied from the fluid supply source M10 to the two operation mechanisms M5 and M8, respectively. Fluid volume adjusting means M11 for adjusting
And operating state detecting means M12 for detecting the operating state of the internal combustion engine M1, and adjusting the fluid amount adjusting means M11 based on the detected operating state so that the characteristic value of the internal combustion engine M1 becomes the target characteristic value. Thus, the control means M13 for changing both valve characteristics is provided. Then, the control means M13 selects a valve having a valve characteristic that allows the characteristic value of the internal combustion engine M1 to more quickly reach the target characteristic value among the intake valve M4 and the exhaust valve M7 based on the operating state at that time, and selects the valve. The amount of fluid supplied to one operating mechanism (M5, M8) that changes the valve characteristic of the selected valve is larger than the amount of fluid supplied to the other operating mechanism (M5, M8). Adjusting means M1
1 is controlled.

Here, the valve characteristic means at least one of the opening timing and the closing timing of the intake valve and the exhaust valve, and the characteristic value of the internal combustion engine refers to the change in the intake valve and the exhaust valve. Characteristic values, such as the output characteristics of the engine, the exhaust characteristics, the fuel consumption rate, and the stability during idling operation.

[0004]

The conventional valve timing control apparatus for an internal combustion engine is constructed as described above, and selects and selects a valve having a valve characteristic that allows the characteristic value of the internal combustion engine to quickly reach a target characteristic value. The control is performed such that the amount of fluid supplied to one operating mechanism that changes the characteristics of the valve is larger than the amount of fluid supplied to the other operating mechanism.

[0005] This is because when a plurality of valve timing controllers with the same oil pressure supply source are operated, the supplied oil pressure decreases (the amount of oil decreases) as compared to when a single valve timing controller is operated. And responsiveness decreases,
This is to make the selected one operate preferentially.

Therefore, the valve timing control device operated with priority can ensure sufficient responsiveness, but the other valve timing control device does not ensure sufficient oil supply, resulting in responsiveness. Was sacrificed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. Even when a plurality of valve timing control devices are operated, a specific valve timing control device is given priority and another valve timing control device is used. The purpose is to ensure the responsiveness without sacrificing the responsiveness of the control device.

Further, the present invention can be realized with the same configuration as that of the conventional device without adding a special device for having the function of the present invention, and the configuration is inexpensive.

[0009]

According to the present invention, an intake valve and an exhaust valve for opening and closing an intake pipe and an exhaust pipe communicating with a combustion chamber of an internal combustion engine, and an intake valve and an exhaust valve driven by fluid pressure are provided. First and second valve timing changing mechanisms for changing valve timing;
And a fluid supply source for supplying a fluid to the second valve timing changing mechanism, and first and second fluid amounts for adjusting a fluid amount supplied from the fluid supply source to the first and second valve timing changing mechanisms. Valve timing control for an internal combustion engine, comprising: an adjusting unit; and a control unit that controls the first and second fluid amount adjusting units so that the actual advance positions of the intake valve and the exhaust valve coincide with the target advance positions. In the apparatus, a control value for one of the first and second fluid volume adjusting means is:
The responsiveness during the operation of the first and second valve timing changing mechanisms is improved by correcting with the other control state of the first or second fluid amount adjusting means.

According to a second aspect of the present invention, in the first aspect of the present invention, the control value for the first and second fluid amount adjusting means is set as follows:
It is characterized in that the correction is performed when the control state of both the first and second fluid amount adjusting means is a follow-up mode for following the target advance position.

A third mode of the present invention is the holding mode according to the first embodiment, wherein one of the control states of the first or second fluid amount adjusting means holds the coincidence with the target advance position. Alternatively, when the other control state of the second fluid amount adjusting means is a follow-up mode in which the second fluid amount adjusting means follows the target advance position, the control value for the fluid amount adjusting means in the holding mode is corrected.

According to a fourth aspect of the present invention, the intake and exhaust valves are arranged such that the actual advance positions of the intake valve and the exhaust valve of the internal combustion engine coincide with the target advance positions by the fluid pressure supplied from the common fluid supply source. In a valve timing control method for an internal combustion engine in which a valve timing of a valve is changed, a control value for changing one valve timing of an intake valve or an exhaust valve is controlled by a control state of changing the other valve timing of the intake or exhaust valve. Responsiveness when the valve timing of the intake and exhaust valves is changed is improved.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, when the control state for changing the valve timing of both the intake valve and the exhaust valve is a follow-up mode in which the control state follows the target advance position, the intake valve and the exhaust valve are controlled. It is characterized in that a control value for changing the valve timing is corrected.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the control of the following mode for following the target advance position is proportional / differential control, and the correction of the control value is a correction for the proportional value. It is characterized by.

According to a seventh aspect of the present invention, in the fifth aspect of the invention, the control of the following mode for following the target advance position is proportional / differential control, and the control value is corrected for the proportional value and the differential value. It is characterized by being.

According to an eighth aspect of the present invention, in the fifth aspect of the invention, the control of the following mode for following the target advance position is a proportional / differential control, and the current control value taking into account the valve characteristics from the proportional and differential values. And the current control value is corrected.

In a ninth aspect of the present invention, in the fourth aspect of the present invention, the control mode for changing the valve timing of one of the intake valve and the exhaust valve is a holding mode for maintaining the coincidence with the target advance position. When the control state of the other valve timing change of the exhaust valve is a follow-up mode that follows the target advance position, the control value for changing the valve timing of the valve in the holding mode is corrected.

According to a tenth aspect of the present invention, in the ninth aspect of the invention, the control of the holding mode for maintaining the coincidence with the target advance position is an integral control, and the correction to the control value is a correction to the integral value. There is a feature.

According to the eleventh aspect of the present invention, the control value for changing the valve timing of one of the intake or exhaust valves is corrected by the control state of changing the other valve timing of the intake or exhaust valve. It is characterized only when the pressure of the supplied fluid is low.

A twelfth aspect of the present invention is characterized in that, in the eleventh aspect of the present invention, the state where the pressure of the fluid is low is a state where the rotational speed of the internal combustion engine is low.

According to a thirteenth aspect, in the eleventh aspect, the state in which the pressure of the fluid is low is a state in which the temperature of the fluid lubricating the internal combustion engine is high.

According to a fourteenth aspect, in the eleventh aspect, the state in which the fluid pressure is low is a state in which the operation amount of the other one of the intake and exhaust valves is large.

According to a fifteenth aspect of the present invention, in the invention of the fourteenth aspect, the state in which the operation amount is large is a state in which a deviation between the target advance position and the actual advance position is large.

According to a sixteenth aspect of the present invention, in the invention of the fourteenth aspect, the state in which the operation amount is large is a state in which the deviation of the control amount is large as compared with the holding mode in which the coincidence with the target advance position is maintained. It is characterized by the following.

According to a seventeenth aspect of the present invention, a motor driven by a common power supply causes the actual advance positions of the intake valve and the exhaust valve of the internal combustion engine to coincide with the target advance positions.
In a valve timing control method for an internal combustion engine which changes a valve timing of an intake valve and an exhaust valve,
By correcting the control value for changing one valve timing of the intake or exhaust valve by the control state of the other valve timing change of the intake or exhaust valve,
It is characterized by improving responsiveness when changing the valve timing of the intake and exhaust valves.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram showing a valve timing control device for an internal combustion engine according to Embodiment 1 of the present invention. In the drawing, an intake pipe 6 for supplying air to a combustion chamber of an internal combustion engine 1 has an air cleaner 2 for purifying intake air, an air flow sensor 3 for measuring the amount of intake air, and an intake air amount. A throttle valve 4 that adjusts and controls the output of the internal combustion engine 1; a throttle sensor 5 that detects the opening of the throttle valve 4; an injector 7 that supplies fuel corresponding to the amount of intake air; and combustion of the internal combustion engine 1 An intake valve V1 for opening and closing the entrance to the chamber is provided. In the combustion chamber of the internal combustion engine 1, a spark plug 8 for generating a spark for burning the air-fuel mixture in the room is provided. Further, an exhaust pipe 9 for discharging the exhaust gas burned by the internal combustion engine 1 has an O ₂ sensor 10 for detecting the amount of oxygen remaining in the exhaust gas, and a TH, which is a harmful gas in the exhaust gas.
A three-way catalyst 11 capable of simultaneously purifying C, CO and NOx, and an exhaust valve V2 for opening and closing an outlet from a combustion chamber of the internal combustion engine 1 are provided.

Sensor plate 12 for detecting crank angle
Although not shown, a protrusion is provided at a predetermined position on the outer periphery, and is attached to the crankshaft and rotates integrally with the crankshaft. The crank angle sensor 13 is for detecting the position of the crankshaft, and emits a signal when the projection of the sensor plate 12 crosses the crank angle sensor 13. The sensor plates 14a and 14b for detecting the cam angle are connected to the intake valves V1 and V1.
The cam angle sensors 15a and 15b are attached to a cam shaft for driving the exhaust valve V2.
a, a signal is emitted when crossing 15b, and the intake valve V1,
The cam angle of the exhaust valve V2 is detected.

Oil control valves 16a and 16
b (corresponding to the first and second fluid volume adjusting means of the present invention)
Is a variable cam phase actuator 20a attached to the camshaft of the intake valve V1 and the exhaust valve V2.
And 20b (corresponding to the first and second valve timing change mechanisms of the present invention) to control the phase of the cam by switching the hydraulic pressure. The fluid supply source 100 supplies a fluid (oil) to the oil control valves 16a and 16b via a fluid passage 101. Engine control unit (ECU) which is a control unit of the present invention
Reference numeral 17 denotes a central processing unit (CPU), a storage unit (RAM,
ROM), and controls the cam phase and also controls the internal combustion engine 1. Reference numeral 18 denotes an ignition coil.

First, before explaining the cam phase angle control of the valve, the general control of the internal combustion engine 1 will be described. The air flow sensor 3 measures the amount of air taken in by the internal combustion engine 1, and the ECU 17 calculates the amount of fuel corresponding to the measured amount of air to drive the injector 7, and at the same time, an appropriate amount of air-fuel mixture in the combustion chamber is supplied to the air-fuel mixture by the ignition plug 8. It controls the time of energization to the ignition coil 18 and the timing of cutoff for ignition at the timing. The amount of air taken in is adjusted by the throttle valve 4 and controls the output generated in the internal combustion engine 1. The exhaust gas burned in the cylinder of the internal combustion engine 1 is
Through a three-way catalyst 11 provided in the middle of the exhaust pipe 9, the harmful substances HC and CO in the exhaust gas.
Purifies NOx to harmless CO ₂ and H ₂ O. Three-way catalyst 11
The exhaust pipe 9 has O
_{The two} sensors 10 are attached to detect the amount of oxygen remaining in the exhaust gas, and the ECU 17 performs feedback control to adjust the fuel amount so that the air-fuel mixture has the stoichiometric air-fuel ratio.

In spite of the fact that the valve timing required originally varies depending on the operating conditions of the internal combustion engine, most of the internal combustion engines up to now have their camshafts of the intake and exhaust valves shifted from the crankshaft to the timing belt and the timing chain. And so on, the opening and closing timing of the valve was constant with respect to the crank angle. However, in recent years, variable valve timing systems have been adopted for the purpose of improving output and reducing exhaust gas and fuel consumption.

The operation of the variable valve timing mechanism (hereinafter, referred to as VVT) system will be described below.
In an internal combustion engine with a fixed valve timing, the rotation of the crankshaft is transmitted to a pulley, a sprocket, and the like via a timing belt, a timing chain, and the like, and the rotation is transmitted to a camshaft that integrally works with the pulley, the sprocket, and the like. In the VVT system, an actuator capable of changing the relative position between the crankshaft and the camshaft is attached instead of a pulley, a sprocket, or the like, so that the valve timing can be controlled.

As shown in FIG. 15, the valve timing of the VVT system is variable between the solid line and the broken line for both the intake valve and the exhaust valve. The solid line of the intake valve is the most retarded position mechanically stopping at the position where the valve overlap is minimum, and the solid line of the exhaust valve is also the most advanced position where it stops at the position where the overlap is minimum. Here, to advance the valve timing is to shift the valve timing to the left side in FIG. 15, and to retard it is to shift to the right side in FIG. As described above, in the VVT system, the valve can be controlled at an arbitrary position within the range from the solid line to the broken line.

An actuator that changes the valve timing is generally driven by a hydraulic pressure that lubricates the internal combustion engine 1. In this embodiment, as shown in FIG. 1, the valve timing is controlled by controlling the amount of oil supplied from the fluid supply source 100 to the cam phase variable actuators 20a and 20b by the oil control valves 16a and 16b. I do.

When the projection of the sensor plate 12 for detecting the crank angle crosses the crank angle sensor 13, the crank angle sensor 13 emits a signal. Similarly, the projections of the sensor plates 14a and 14b for detecting the cam angle
The cam angle sensors 15a and 15b emit signals when they cross the points a and 15b. The ECU 17 detects a cam angle with respect to the crank angle, that is, an actual valve timing, as an actual advance angle amount based on output signals of the crank angle sensor 13 and the cam angle sensors 15a and 15b.

Further, the ECU 17 calculates a valve timing corresponding to the requirements such as the exhaust gas performance and the output performance as a target advance amount according to the operating conditions of the internal combustion engine 1. For example,
The target advance angle map, which has been converted into a two-dimensional map based on the rotation speed of the internal combustion engine 1 and the charging efficiency, is previously stored in the RO in the ECU 17.
The target advance amount is obtained by referring to a map based on the rotation speed and the charging efficiency at that time.

The actual advance angle is set at zero at the mechanical stop position indicated by the solid line of the intake / exhaust valve timing in FIG. Similarly, the target advance angle is set such that the mechanically stopped valve timing is zero.

The actuators 20a and 2 control the oil control valves 16a and 16b so that the actual advance amount coincides with the target advance amount, thereby varying the valve timing.
The control of the advance amount is performed by switching the hydraulic pressure introduction to 0b. That is, the intake air is controlled to be advanced based on the most retarded position, and the exhaust gas is controlled to be retarded based on the most advanced position.

Next, control of a normal variable valve timing mechanism (VVT) system will be described with reference to FIGS. 2, 3, and 7, taking the intake side as an example. 2, 3, and 7 are stored as programs in the ROM in the ECU 17 and are executed at predetermined timings. FIG. 2 is a processing flowchart for determining the control mode of the variable valve timing mechanism. FIG. 3 shows a proportional / differential control mode (PD) which is a mode for following a target position by a control mode determination process.
Mode). FIG. 7 shows the processing content when the control mode determination processing determines that the holding mode is the matching mode with the target position.

First, the control mode determination processing of FIG. 2 will be described. In S201, a deviation (ΔIP) between the target advance amount (IPt) and the detected advance amount (IPd) is calculated. Next, in S202, it is determined whether the target advance amount (IPt) is zero. If the target advance amount (IPt) is zero,
The processing shifts to S206, where the oil control valve 1
It is determined that the control current is the minimum current mode in which the control current at 6a is minimized and the valve overlap is minimized to the most retarded position (the most advanced position in the case of the exhaust side).

If it is determined in step S202 that the target advance amount (IPt) is larger than zero, the process proceeds to step S203.
The advance angle deviation (ΔIP) is within a predetermined value range (−IPh to I
Ph). If it is within the predetermined range, the target advance angle (IPt) and the detected advance angle (IPd) are almost the same, and it is determined that the state is the holding mode for maintaining the state.

If the deviation (ΔIP) is not within the range of the predetermined value in S203, the detected advance angle (IPd) does not follow the target advance angle (IPt). It is determined that the mode is the (PD) mode.
When the mode determination is completed as described above, the processing in FIG. 2 ends. The value (IPh) of the predetermined determination range in S203 is set to a value of about 1 [degCA] which does not affect drivability and exhaust gas even if the valve timing changes.

When it is determined in the process of FIG. 2 that the mode is the PD mode, the proportional and differential control of FIG. 3 is performed in order to follow the target advance amount (IPt).

First, in S301, the target advance amount (IP
The proportional value (IVp) is calculated by multiplying the deviation (ΔIP) between t) and the detected advance amount (IPd) by a proportional gain (IPgain). Here, the proportional gain is a value set so that the detected advance amount follows the target advance amount with good responsiveness. For example, the responsiveness is actually confirmed while the internal combustion engine 1 is operating. And stored in the ROM in the ECU 17.

Next, in step S302, the difference between the difference (ΔIP) and the previous value of the difference (ΔIP [I-1]) is used to calculate the differential gain (I
Dgain) to calculate a differential value (IVd).
Here, the previous value of the deviation (ΔIP [I-1]) is the deviation (ΔI [I-1]) calculated last time in the process of FIG.
P). The differential gain is set similarly to the proportional gain, and is stored in the ROM.

Next, in step S303, the proportional value (IVp)
And the differential value (IVd) and the proportional differential value (IVpd)
And Then, in S304, the proportional differential value (IV
pd), the values shown in FIG. 16 are interpolated with reference to a table preset in the ROM, and the proportional gain [degCA / s
ec], the control current deviation (IDApd) [mA] is calculated.
The table values in FIG.
The characteristic value of a is set, and is a characteristic obtained by measuring the crank angular velocity at each current value in a state where the spool type solenoid valve having the flow rate characteristics shown in FIG.

Next, in step S305, the holding current learning value (IArn) obtained by learning the current value when the target advance amount and the detected advance amount during the holding mode control match and the control current deviation (IDApd) are calculated. The final control current value (I
Apd). Since the current value in the state where the target advance amount and the detected advance amount are coincident changes due to variations in components, etc., learning as the holding current learning value eliminates the influence of the variation on control responsiveness. The data in FIG. 16 is set such that the position where the target advance angle and the detected advance angle coincide with each other is zero.

Then, in S306, the control current value (I
Apd) is converted into a duty value and output to the oil control valve 16a.

When it is determined in the process of FIG. 2 that the mode is the holding mode, the integral control for minutely changing the control current value is performed to control the detected advance amount to more accurately follow the target advance amount. It is carried out.

FIG. 7 is a flow chart showing the control contents in the holding mode.
If it is determined to be 5), this processing is executed.

In step S701, the deviation (ΔIP) between the target advance amount and the detected advance amount is multiplied by the integral gain (IIgain), and the result is added to the previous integral value (IDAi [I-1]). IDAi). Here, the integral gain is a value set in advance similarly to the proportional gain and the differential gain.
Further, the previous value of the integral value is an integral value calculated last time in the process of FIG. 7 executed at each predetermined timing.

Next, in S702, the control current value (IAi) is calculated by adding the integral value (IDAi) to the holding current learning value (IArn), and is output to the oil control valve 16a in S306.

When it is determined in the processing of FIG. 2 that the current mode is the minimum current mode, control is performed with the minimum control current value to the oil control valve 16a so that the valve timing becomes the minimum valve overlap position. . Here, the minimum current may be a non-energized state (0 [mA]),
The valve timing is 1 at the current value that does not operate in the advance direction.
If the current value is set to about 00 [mA], the variable valve timing mechanism (VVT) is operated from the minimum current mode.
The response when shifting to the D mode is good.

As described above, control accuracy is improved by changing the control method according to the control mode determined in FIG. 2 and controlling the output current value of the valve. However, the content described above is only for the intake side,
As shown in FIG. 1, the present control device relates to the control of a plurality of variable valve timing mechanisms for both the intake and the exhaust. Therefore, the same control is performed on the exhaust side.
Here, when the intake and exhaust are operated at the same time, the required oil amount increases as compared with the case of only intake and only of exhaust, so that a decrease in hydraulic pressure is increased and control responsiveness may be reduced.

In the conventional apparatus shown in FIG. 18, the higher priority is selected and the selected side is preferentially operated so that the responsiveness is improved. In this method, the lower priority is assigned to the responsiveness. Will decrease. Therefore, in the embodiment of the present invention, as described below, a method is proposed in which the oil control valve on the side not selected by priority has no deterioration factor such as a decrease in responsiveness.

FIG. 4 is a flowchart showing specific control contents of the intake side variable valve timing mechanism (intake side VVT) according to the first embodiment of the present invention.
FIG. 3 which is the control when it is determined that the mode is the D mode is replaced. Also, in FIG. 4, the control contents having the same numbers as those in FIG. 3 are the same as those in FIG.

In step S401, the control mode of the exhaust-side variable valve timing mechanism (exhaust-side VVT) is determined. Here, unless the exhaust side VVT follows the target advance position (PD mode), it is either the minimum current mode or the holding mode, and is in a constant state at a certain valve timing. Accordingly, the decrease in oil pressure due to the operation of the exhaust VVT is small, and even if the intake-side VVT is directly PD-controlled, the control responsiveness does not decrease.
The process proceeds to 1 to perform a proportional value calculation without performing the correction according to the present embodiment.

If it is determined in step S401 that the exhaust-side VVT is in the PD mode, the intake and exhaust are operating simultaneously, and it is necessary to supply oil to both actuators. Since the oil pressure drop is greater than the state in which the oil pressure is reduced, the process proceeds to S402, and the control current value is increased by performing a correction Kp (Kp>1; for example, about 1.2) corresponding to a decrease in responsiveness due to the oil pressure drop. To improve responsiveness.

As described above, in the present embodiment, when operating the intake-side VVT, it is determined whether or not correction to a proportional value is performed based on the operating state of the exhaust-side VVT. When it is determined that the correction is necessary, the correction corresponding to the decrease in the response due to the decrease in the hydraulic pressure is performed. As a result, even in the simultaneous operation state of the intake and exhaust VVTs in which the oil pressure is lower than the operation state of only the intake side VVT, the operation can be performed without a decrease in responsiveness.

The same control as in the flowchart of FIG. 4 is also applied to the exhaust-side VVT. When the intake VVT is activated, the exhaust-side VVT is also compensated for a decrease in oil pressure, and the intake-side VVT is corrected.
Like VT, there is no decrease in responsiveness. Therefore, during simultaneous operation of the intake and exhaust VVTs, the proportional value is corrected for both,
Responsiveness is improved.

FIG. 5 is a flowchart showing another correction method according to the first embodiment. Although only the proportional value is corrected in the process of FIG. 4, here, as shown in FIG. 5, when the mode of the exhaust VVT is the PD mode and the correction is necessary, the proportional value is corrected in S402. Correction Kp corresponding to a decrease in responsiveness due to a decrease in hydraulic pressure, and then S
The processing may shift to 501, and a correction Kd (Kd>1; for example, about 1.2) corresponding to a decrease in responsiveness may be performed on the differential value.

FIG. 6 is a flowchart showing an improvement in another correction method according to the first embodiment. In the process of FIG. 4, the correction is performed on the proportional value, but instead of the correction on the proportional value, the control current value I in S601 in FIG.
A similar effect can be obtained by performing a correction Kpd (Kpd>1; for example, about 1.2) on DApd.

The above correction values (Kp, Kd, Kpd)
Although there is an effect of the correction even if the preset constant is used, it is changed by the rotation speed (refer to the interpolation of the two-dimensional table by the rotation speed; in this case, Kp, Kd, and Kpd are set so as to be large at low rotation and small at high rotation. ), Change due to deviation between target advance amount and detected advance amount (refer to interpolation of two-dimensional table by deviation; in this case, Kp, Kd, and Kpd are both ΔIP
Is larger, the correction value is set to be larger), change by rotation speed and deviation (refer to interpolation of three-dimensional map by rotation speed and deviation; in this case, Kp, Kd, and Kpd are both low rotation, ΔIP
Is set to a larger value, a higher rotation is set, and the smaller the ΔIP is, the smaller the value is, the more accurate the correction can be made.

FIG. 13 is a time chart for explaining the above contents. It can be seen that when the intake and exhaust VVTs are operated simultaneously and there is no correction (dashed line), the response time becomes longer due to a large decrease in oil pressure, compared to the operation when only the intake VVT is operated (two-dot chain line). Next, by performing the correction of the first embodiment (solid line), the decrease in the responsiveness due to the decrease in the oil pressure is used to reduce the oil control valve (OC) of the intake VVT.
V) The response time is improved by compensating for the increase in current. Further, even in the case of the exhaust-side VVT, the correction of the first embodiment is performed because the intake-side VVT is in operation, and the responsiveness does not decrease as in the case of the intake-side VVT.

Embodiment 2 In the above embodiment, the intake-side VVT changes the detected advance angle (IPd) to the target advance angle (IPd).
The processing in the case of the PD mode for following t) has been described. Since the oil pressure is reduced when the exhaust side VVT is operating, the stability of the holding control is affected even when the intake side VVT is in the hold mode in which the intake side VVT is held at the intermediate position, and the shift to the retard side is performed. Phenomenon occurs. In the second embodiment, the target advance angle (IPt) and the detected advance angle (I
The present invention proposes a method for ensuring the stability of the holding control of the variable valve timing mechanism (VVT) in the holding mode in which the deviation (ΔIP) from Pd) is within a predetermined range and holding the state.

FIG. 8 is a flow chart showing the contents of processing in the intake side VVT holding mode according to the second embodiment.
It replaces FIG. Here, similarly to the control in the PD mode of the first embodiment, in S401, the exhaust side VV
It is determined whether or not T is in the PD mode, and if it is not the PD mode, the flow shifts to S701 to calculate the integral value without performing correction by calculation. If it is determined in step S401 that the exhaust-side VVT is in the PD mode, the exhaust-side VVT is operating and the hydraulic pressure is low.
Then, by correcting the integral value with the correction value Ki (Ki>1; for example, about 1.1), control position fluctuation due to a decrease in hydraulic pressure is suppressed. As a result, the position stability can be improved.

The correction value Ki may be a fixed value. However, a variable for the rotation speed that affects the hydraulic pressure (see interpolation of a two-dimensional table based on the rotation speed), a variable for the deviation between the target advance amount and the detected advance amount ( Variables based on the number of rotations and deviation (refer to interpolation of two-dimensional table by deviation)
(See Dimension Map Interpolation), it is possible to perform more accurate control.

FIG. 14 is a time chart for explaining the operation according to the second embodiment. Since the hydraulic pressure decreases due to the operation of the PD control which is the follow-up mode of the exhaust side VVT,
On the intake side VVT side in the holding mode, the steady state stability is impaired, and the fluctuation (decrease) occurs as shown by the broken line in the figure. Therefore, by correcting the integrated value of the intake side VVT according to the second embodiment and increasing the oil control valve (OCV) current, the responsiveness is improved as shown by the solid line, and the steady stability is secured. There is almost no fluctuation.

Embodiment 3 In the above-described embodiment, the correction is performed for the entire engine operating region for controlling the variable valve timing mechanism (VVT). However, when the hydraulic pressure is sufficiently ensured, the required oil amount introduced to the VVT actuator is adjusted. , The hydraulic pressure is small even during the operation of the VVT, and there is almost no reduction in responsiveness. Similarly, when the operating angle of the VVT actuator is small, the hydraulic pressure drop is small, so that sufficient responsiveness can be ensured without performing correction. May lead to an increase.

Therefore, in the present embodiment, a method for correcting only the engine operating region that needs to be corrected will be described.

FIG. 9 is a flowchart showing the contents of processing on the intake side VVT according to the third embodiment. This process is a control when it is determined that the mode is the PD (proportional / differential) mode in the control mode determination process of FIG. 2, and is replaced with FIG. 3 and is a control for performing the correction only in the engine operating state where the correction is required. It shows.

First, in S901, it is determined whether or not the engine speed is equal to or higher than a predetermined value. Here, the predetermined value is a rotation speed at which the hydraulic pressure is sufficiently secured, for example, 2000 r.
/ M or more. If the rotation speed is equal to or higher than the predetermined rotation speed, the hydraulic pressure is sufficient, and it is determined that the intake / exhaust VVT can operate without a decrease in responsiveness even if the intake and exhaust VVTs operate simultaneously. Not performed.

If the engine speed is low in S901,
When the intake and exhaust VVTs are simultaneously operated, it is determined that the responsiveness is reduced, and the flow shifts to S401, where the exhaust VVT becomes P
If the mode is the D mode, the process proceeds to S402, and the correction for the proportional value described in the first embodiment is performed.

FIG. 10 is a flowchart showing another processing content according to the third embodiment. Here, since the viscosity of the engine lubricating oil decreases due to an increase in the oil temperature and the oil pressure decreases, the responsiveness also decreases. Therefore, in the process of FIG. 10, the correction is not performed at a low oil temperature where the hydraulic pressure is secured, but is corrected only at a high oil temperature.

First, in S1001, it is determined whether or not the temperature of the engine lubricating oil is equal to or higher than a predetermined value. Here, the fact that the oil temperature is equal to or higher than the predetermined value is estimated based on whether or not operation at a high rotation speed, a high load, and a low vehicle speed is continued. For example, rotation speed 4000r
/ M, the filling efficiency is 50% or more, and the vehicle speed is 40 km / h or less. If it is estimated in step S1001 that the oil temperature is not high, the process proceeds to step S301 to perform a proportional value calculation without correction. On the other hand, if it is estimated in S1001 that the oil temperature is high, the flow shifts to S401, where the exhaust side VVT is proportional.
It is determined whether the mode is the differential (PD) mode. If the mode is the PD mode, the process proceeds to S402, and the proportional value calculation with correction described in the first embodiment is performed.

FIG. 11 is a flowchart showing another processing content according to the third embodiment. Here, when the deviation between the target advance amount and the detected advance amount is large, a large amount of oil is supplied to the VVT actuator to control the detected advance amount to quickly follow the target advance amount. However, when the deviation between the target advance amount and the detected advance amount is small, the oil supply to the VVT actuator is slow, so the oil pressure drop is small and the correction is required. And not. Therefore, in the process of FIG. 11, it is determined whether correction is to be performed based on the magnitude of the deviation between the target advance amount and the detected advance amount, and the controllability is improved by switching.

In step S1101, the target advance amount (IP
It is determined whether or not the difference (ΔIP) between t) and the detected advance amount (IPd) is equal to or greater than a predetermined value. Here, the predetermined value is a deviation that causes a large decrease in oil pressure when the VVT actuator is operated, and is, for example, 20 degCA or more. If the deviation (ΔIP) is small in S1101, the process proceeds to S301 to perform a proportional value calculation without correction. Deviation (ΔIP) in S1101
If the exhaust VVT is larger than PD
Mode is determined, and if the mode is the PD mode, S402
To perform a proportional value calculation with correction.

By determining the value of the control current (target current or detected current) of the oil control valve instead of the deviation between the target advance angle and the detected advance angle, the same effect as that of FIG. 11 can be achieved. It is possible. FIG. 12 is a flowchart showing the method.

At S1201, it is determined whether the difference between the control current value and the holding current learning value is equal to or greater than a predetermined value.
Here, the oil control valve has a flow rate characteristic shown in FIG.
The passage between the hydraulic chamber that acts on the advance side and the hydraulic chamber that acts on the retard side of the actuator is closed, and the holding control of the advanced position is performed. Since the current value to be controlled changes, the current value is learned, and the current control is performed based on the learned current value.

Therefore, as the deviation between the target advance amount and the detected advance amount becomes larger, the control current value and the holding current value are increased, and V
Since the oil supply to the VT actuator is increased and the speed of the advance or retard is made to converge at a high speed, if the current deviation is large, the decrease in the hydraulic pressure is large.

When determining the deviation between the holding current learning value and the control current value in S1201, the predetermined reference value is a deviation that causes a large decrease in oil pressure when the VVT actuator is operated, and is, for example, 200 mA or more. S120
If the current deviation is small in step 1, the flow advances to step S301 to perform a proportional value calculation without correction. In step S1201, if the current deviation is large, the process proceeds to step S401 to determine whether the exhaust side VVT is in the PD mode.
Proceeding to 402, a proportional value calculation with correction is performed.

In the description of FIGS. 9 to 12, the correction of the proportional value replacing FIG. 4 has been described. However, the correction of the proportional value may be applied to FIGS.
S901, S1001, and S901 before the mode determination of
By inserting the processing of steps 1101 and S1201, equivalent effects can be obtained.

As described above, according to the present embodiment, it is possible to improve the position control accuracy of the variable valve timing mechanism (VVT) by performing the correction only when the engine is in the required operating state.

Other Embodiments In the first to third embodiments, an example has been described in which the intake-side VVT is corrected while observing the operating state of the exhaust-side VVT. However, the same applies to the case where the exhaust-side VVT is corrected while observing the operating state of the intake-side VVT. The effect is obtained.

In the first to third embodiments, the intake side VV
T and the exhaust-side VVT are simultaneously operated. For example, only the intake-side VVT or the exhaust-side VVT in a V-type engine is described.
It may be used for control of different banks only by VT,
The same effect can be obtained.

Further, VV on the intake side of the V-type engine
The same effect can be obtained by using two or more VVT controls, such as both T and the exhaust-side VVT.

Further, in the first to third embodiments, the VVT control by the hydraulic drive has been described. However, the same effect for improving the responsiveness can be obtained even if the method is used as a correction method in the case where the voltage drop by the motor type occurs. can get.

In the first to third embodiments, the one-sided VVT
Although the method is described as a method of increasing the amount of increase during simultaneous VVT operation, one-side VV
The same effect can be obtained by the method of compensating the amount of decrease during the T operation.

[0088]

According to the first or fourth aspect of the present invention,
The control value for changing one valve timing of the intake or exhaust valve is corrected based on the control state of the other valve timing change of the intake or exhaust valve. It is possible to prevent a decrease in responsiveness, thereby improving drivability and preventing deterioration of exhaust gas.

According to the second or fifth to eighth aspects of the present invention, when the control mode for changing the valve timing of both the intake valve and the exhaust valve is a follow-up mode in which the control valve follows the target advance position, the intake valve and the exhaust valve are controlled. Since the control value for changing the valve timing of the exhaust valve is corrected, the responsiveness does not decrease even in the simultaneous operation of the valve timing control of the intake valve and the exhaust valve in which the fluid pressure has decreased.

According to the third or ninth to tenth aspects of the present invention, the control mode for changing the valve timing of one of the intake valve and the exhaust valve is a holding mode for maintaining the coincidence with the target advance position. When the control state of the other valve timing change of the intake valve or the exhaust valve is a follow-up mode that follows the target advance position, the control value for changing the valve timing of the valve in the holding mode is corrected. Control position fluctuation due to a decrease in the fluid pressure of the valve on the holding mode side is suppressed, and position stability for holding is improved.

According to the eleventh to sixteenth aspects of the present invention, the correction is made only when the pressure of the fluid supplied from the fluid supply source is in a low state. Unnecessary correction is not performed.

According to the seventeenth aspect of the present invention, there is provided a valve timing control method for an internal combustion engine in which the valve timing of an intake valve and an exhaust valve is changed by a motor driven by a common power supply. The control value for changing the valve timing of the intake and exhaust valves is corrected based on the control state of the other valve timing change of the intake or exhaust valve. The responsiveness when changing is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a valve timing control device for an internal combustion engine according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the first embodiment of the present invention;

FIG. 3 is a flowchart for explaining the operation of the first embodiment of the present invention;

FIG. 4 is a flowchart for explaining the operation of the first embodiment of the present invention;

FIG. 5 is a flowchart for explaining the operation of the first embodiment of the present invention;

FIG. 6 is a flowchart for explaining the operation of the first embodiment of the present invention;

FIG. 7 is a flowchart for explaining the operation of the second embodiment of the present invention;

FIG. 8 is a flowchart for explaining an operation according to the second embodiment of the present invention;

FIG. 9 is a flowchart for explaining the operation of the third embodiment of the present invention;

FIG. 10 is a flowchart for describing an operation according to the third embodiment of the present invention;

FIG. 11 is a flowchart for describing an operation according to the third embodiment of the present invention;

FIG. 12 is a flowchart for describing an operation according to the third embodiment of the present invention;

FIG. 13 is a time chart for explaining the operation of the first embodiment of the present invention;

FIG. 14 is a time chart for explaining an operation of the second embodiment of the present invention;

FIG. 15 is a diagram for explaining the operation of the embodiment of the present invention;

FIG. 16 is a diagram for explaining the operation of the embodiment of the present invention;

FIG. 17 is a diagram for explaining the operation of the embodiment of the present invention;

FIG. 18 is a configuration diagram showing a conventional valve characteristic control device for an internal combustion engine.

[Explanation of symbols]

Reference Signs List 1 internal combustion engine, 6 intake pipe, 9 exhaust pipe, 12 sensor plate, 13 crank angle sensor, 14a, b sensor plate, 15a, b cam angle sensor, 16a, b
Oil control valve, 17 ECU, 18 ignition coil, 20a, b Cam phase variable actuator,
V1 intake valve, V2 exhaust valve, 100 fluid supply.

Continued on the front page F-term (reference) 3G018 AB02 AB07 AB10 AB17 BA29 BA33 CA20 DA70 EA02 EA03 EA11 EA17 EA35 FA01 FA09 GA02 GA03 3G092 AA01 AA11 AB02 DA08 DG05 DG08 EA03 EA04 EB02 EB03 EC01 EC09 FA06 FA11 GA17 HAZZZ01 HA01 HA19 JA03 JA11 KA00 KA24 LA07 LC03 LC08 NA03 NA05 NA07 NC02 ND02 ND04 NE11 NE12 PA01Z PA11Z PD02Z PE01Z PE04Z PE08Z PE10A

Claims (17)

[Claims] An intake valve and an exhaust valve for opening and closing an intake pipe and an exhaust pipe communicating with a combustion chamber of an internal combustion engine, and first and second valves for changing valve timing of the intake and exhaust valves by being driven by fluid pressure. A valve timing changing mechanism, a fluid supply source for supplying a fluid to the first and second valve timing changing mechanisms, and a fluid supplied from the fluid supply source to the first and second valve timing changing mechanisms First and second fluid amount adjusting means for adjusting the amount; and the first and second fluid amount adjusting means such that the actual advance positions of the intake valve and the exhaust valve coincide with the target advance position. In the valve timing control device for an internal combustion engine provided with a control unit for controlling, the control unit sets a control value for one of the first or second fluid amount adjusting means to the first or second fluid amount adjusting means. The valve timing control of the internal combustion engine is improved by correcting the other control state of the second fluid amount adjusting means to improve the responsiveness of the first and second valve timing changing mechanisms during operation. apparatus. 2. The controller according to claim 1, wherein the control value of the first and second fluid flow rate adjusting means follows a control state of both the first and second fluid flow rate adjusting means to a target advance position. The valve timing control device for an internal combustion engine according to claim 1, wherein the correction is performed when the mode is a following mode. 3. The control unit according to claim 1, wherein one of the control states of the first or second fluid amount adjusting unit is in a holding mode in which the first or second fluid amount adjusting unit is in agreement with a target advance position. 2. The valve according to claim 1, wherein the control value for the fluid amount adjusting unit in the holding mode is corrected when the other control state of the amount adjusting unit is a follow-up mode that follows the target advance position. Timing control device. 4. The valve timing of an intake valve and an exhaust valve is adjusted so that actual advance positions of an intake valve and an exhaust valve of an internal combustion engine coincide with target advance positions by a fluid pressure supplied from a common fluid supply source. In the valve timing control method for an internal combustion engine, the control value for changing one valve timing of the intake or exhaust valve is corrected by a control state of changing the other valve timing of the intake or exhaust valve. A valve timing control method for an internal combustion engine, characterized by improving responsiveness when changing the valve timing of the intake and exhaust valves. 5. A control value for changing valve timings of the intake valve and the exhaust valve in a follow-up mode in which a control state of changing both valve timings of the intake valve and the exhaust valve follows a target advance position. The valve timing control method for an internal combustion engine according to claim 4, wherein the correction is performed. 6. The internal combustion engine according to claim 5, wherein the control in the following mode for following the target advance position is proportional / differential control, and the correction of the control value is a correction for the proportional value. Engine valve timing control method. 7. The control according to claim 5, wherein the control in the following mode for following the target advance position is proportional / differential control, and the correction of the control value is a correction for the proportional value and the differential value. A valve timing control method for an internal combustion engine according to the above. 8. The control in the following mode for following the target advance position is proportional / differential control. A current control value in consideration of valve characteristics is obtained from the proportional and differential values, and the current control value is corrected. The valve timing control method for an internal combustion engine according to claim 5, wherein: 9. The control mode for changing the valve timing of one of the intake valve and the exhaust valve is a holding mode for maintaining coincidence with the target advance position, and controlling the change of the other valve timing of the intake valve or the exhaust valve. 5. The valve timing control method for an internal combustion engine according to claim 4, wherein a control value for changing a valve timing of the valve in the holding mode is corrected when the state is a follow-up mode that follows the target advance position. . 10. The control according to claim 9, wherein the control of the holding mode for maintaining the coincidence with the target advance position is integral control, and the correction to the control value is a correction to the integral value. Valve timing control method for an internal combustion engine. 11. A method for correcting a control value for changing one valve timing of the intake or exhaust valve based on a control state of changing the other valve timing of the intake or exhaust valve, the control value being supplied from a fluid supply source. 11. The valve timing control method for an internal combustion engine according to claim 4, wherein the method is performed only when the fluid pressure is low. 12. The valve timing control method for an internal combustion engine according to claim 11, wherein the state in which the pressure of the fluid is low is a state in which the rotation speed of the internal combustion engine is low. 13. The valve timing control method for an internal combustion engine according to claim 11, wherein the state in which the pressure of the fluid is low is a state in which the temperature of the fluid lubricating the internal combustion engine is high. 14. The valve timing control method for an internal combustion engine according to claim 11, wherein the state in which the pressure of the fluid is low is a state in which the operation amount of the other one of the intake and exhaust valves is large. . 15. The valve timing control method for an internal combustion engine according to claim 14, wherein the state in which the operation amount is large is a state in which a deviation between the target advance position and the actual advance position is large. 16. The state in which the operation amount is large is a state in which the deviation of the control amount is large as compared with the holding mode in which the coincidence with the target advance position is maintained.
5. The method for controlling valve timing of an internal combustion engine according to claim 4. 17. The valve timing of an intake valve and an exhaust valve is changed by a motor driven by a common power supply so that actual advance positions of an intake valve and an exhaust valve of an internal combustion engine coincide with target advance positions. In the valve timing control method for an internal combustion engine, a control value for changing one valve timing of the intake or exhaust valve is improved so as to improve responsiveness when changing the valve timing of the intake and exhaust valves. A valve timing control method for an internal combustion engine, wherein the correction is made based on a control state of changing the other valve timing of the intake or exhaust valve.