JP2000104571A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of abnormality of a VVT (a variable valve timing control mechanism) due to lodging of a foreign matter in an OCV (an oil pressure control valve). SOLUTION: When pedalling of an accelerator pedal is not effected during operation of a VVT 11 and an idle switch 4 is turned ON and the number of revolutions of an engine is within a given range, cleaning operation of an OCVT 10 is executed. In this case, the OCV 10 is charged alternately with a maximum current and a minimum current and only the given number of revolutions is widely fluctuated in a given time so that a displacement amount of the linear solenoid of the OCV 10 is increased to a maximum and decreased to a minimum. In this way, discharge for removal is effected before the number of revolutions of an engine is reduced to the number of idle revolutions even when lodging of a foreign matter in the OCV 10 occurs. This constitution prevents the occurrence of abnormality of the VVT 11 and especially stabilizes the number of idle revolutions right after an internal combustion engine 1 is brought into idle operation.

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 apparatus for an internal combustion engine which can change the opening / closing timing of at least one of an intake valve and an exhaust valve of the internal combustion engine in accordance with an operation state. The present invention relates to a valve timing control device for an internal combustion engine that controls the pressure of hydraulic oil introduced from a pump to a variable valve timing control mechanism using a hydraulic control valve.

[0002]

2. Description of the Related Art Conventionally, as a prior art document relating to a valve timing control device for an internal combustion engine, Japanese Patent Application Laid-Open No. 8-28 is disclosed.
One disclosed in Japanese Patent Publication No. 219 is known. In this case, the hydraulic pressure of hydraulic oil supplied to a variable valve timing control mechanism is controlled using a hydraulic control valve.
Then, a technique is disclosed in which, when foreign matter is caught in the hydraulic control valve, the opening amount of the hydraulic control valve is increased to discharge and remove the caught foreign matter.

[0003]

When the hydraulic control valve is abnormal, the hydraulic control valve is reciprocated at a predetermined duty ratio in order to discharge and remove the foreign matter that causes the abnormality. As described above, there has been a problem that the operating state of the internal combustion engine becomes unstable sometimes due to the increase or decrease of the flow rate of the hydraulic oil regardless of the operating state of the internal combustion engine.

Accordingly, the present invention has been made to solve such a problem, and an abnormality of the variable valve timing control mechanism due to foreign matter being caught in a hydraulic control valve for controlling the hydraulic pressure of hydraulic oil of the variable valve timing control mechanism. It is an object of the present invention to provide a valve timing control device for an internal combustion engine, which can prevent the occurrence of an internal combustion engine.

[0005]

According to the valve timing control apparatus for an internal combustion engine of the present invention, the operating state detecting means detects that the internal combustion engine is in a predetermined operating state while the variable valve timing control mechanism is operating. Then, a predetermined cleaning operation is performed on the hydraulic control valve by the valve control means. As the cleaning operation of the hydraulic control valve, for example, a maximum current and a minimum current are alternately supplied to the hydraulic control valve, and a predetermined time is set so that the displacement amount of the linear solenoid of the hydraulic control valve becomes maximum and minimum. Is greatly changed by a predetermined number of times. This allows, for example,
Even if foreign matter is caught in the hydraulic control valve, it is discharged and removed before the engine speed drops to the idle speed. Thus, an abnormality of the variable valve timing control mechanism is prevented beforehand, and in particular, the idle speed immediately after the internal combustion engine is in idle operation can be stabilized.

According to a second aspect of the present invention, the predetermined operation state of the valve control means is determined when the accelerator pedal is not depressed and the engine speed is within a predetermined range. As described above, during the deceleration state of the vehicle due to the engine brake of the internal combustion engine or during fuel cut, the engine speed is in a stable rotation range where torque fluctuation does not easily occur. Even if the operation of the valve timing control mechanism is somewhat unnatural, the variable valve timing control mechanism is prevented from being abnormal without adversely affecting the operation state at this time. It is possible to stabilize the idle speed immediately after the engine has become idle.

According to the third aspect of the present invention, when the target advance value for the variable valve timing control mechanism corresponding to the operating state of the internal combustion engine detected by the operating state detecting means is the maximum, The maximum current is supplied to the hydraulic control valve by the valve control means,
The variable valve timing control mechanism comes into contact with the most advanced angle side and is fixed. As a result, the variable valve timing control mechanism can obtain a stable maximum advancing position with the highest response speed and a small hydraulic loss. Further, when the target advance value for the variable valve timing control mechanism corresponding to the operation state of the internal combustion engine detected by the operation state detection means is minimum, the minimum current is supplied to the hydraulic control valve by the valve control means, The variable valve timing control mechanism is controlled so as to be near the most retarded angle. This makes it possible to improve the response of the variable valve timing control mechanism when the internal combustion engine starts up from the idle operation.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

FIG. 1 is a schematic configuration diagram showing a double overhead cam type internal combustion engine to which an internal combustion engine valve timing control apparatus according to an embodiment of the present invention is applied, and peripheral devices thereof.

In FIG. 1, 1 is an internal combustion engine, 2 is an intake passage, 3 is a throttle valve disposed in the middle of the intake passage 2, and 4 is an idle switch for detecting an idle operation state when the throttle valve 3 is fully closed. Reference numeral 5 denotes an ISC (IdleSpring) which is disposed in the middle of the bypass passage of the throttle valve 3 and controls the idle speed to reach the target speed.
eed Control: idle speed control valve, 6 is an intake pressure sensor for detecting an intake pressure PM signal on the downstream side of the throttle valve 3 disposed in the intake passage 2, and 7 is the internal combustion engine 1 near the end of the intake passage 2. An injector (fuel injection valve) 8 is provided to the combustion chamber of the internal combustion engine 1 to ignite an air-fuel mixture in the combustion chamber of the internal combustion engine 1 using a spark plug 9.

Reference numeral 13 denotes a crank angle sensor for detecting a rotation angle θ 1 signal of the crankshaft 12 as a drive shaft of the internal combustion engine 1, based on the rotation angle θ 1 signal from the crank angle sensor 13. The number NE is calculated. 16 detects the rotation angle θ2 signal of the camshaft 15 as the driven shaft on the intake valve 14 side of the intake valve 14 and the exhaust valve 17 of the internal combustion engine 1, and detects the rotation angle θ1 signal from the crank angle sensor 13. This is a cam angle sensor for calculating an actual advance angle value (also referred to as an actual relative rotation angle or an actual displacement angle) from a phase difference.

Reference numeral 10 denotes an oil-flow control valve (Oil-flow Control Valve) for adjusting and controlling the hydraulic pressure of the hydraulic oil.
V "), and 11 is a hydraulic pressure adjusted by the OCV 10 to obtain a target advance angle value (also referred to as a target relative rotation angle or a target displacement angle) which is a target phase difference between the camshaft 15 and the crankshaft 12. Variable Valve Timing Control Mechanism (Variable Valve Timing Control Mechanism) installed on the intake valve 14 side as an actuator to be controlled
m: hereinafter referred to as “VVT”), 20 detects the operating state of the internal combustion engine 1 based on input signals from various sensors, calculates optimal control values, and calculates the ISC valve 5, the injector 7, the igniter 8, and the OCV 10 ECU (Electronic Control Unit) that outputs drive signals to the
It is. It should be noted that an oil pump for pumping hydraulic oil to the OCV 10, an oil passage, and the like are omitted.

Next, the electrical configuration of the ECU 20 will be described with reference to FIG.

In FIG. 2, an ECU 20 includes a CPU 21 as a well-known central processing unit, a ROM 22 storing a control program, a RAM 23 storing various data, and an analog signal of an intake pressure PM signal from the intake pressure sensor 6 converted into a digital signal. A / D conversion circuit 24 for converting the rotation angle θ1 signal from crank angle sensor 13 and cam angle sensor 16
Shaping circuit 2 for shaping the rotation angle θ2 signal from
5. ON / OFF from idle switch 4
(OFF) signal and A / D conversion circuit 24 and waveform shaping circuit 2
The drive signal based on the control value calculated by the CPU 21 based on the various information from
It is configured as a logical operation circuit including a C valve 5, an injector (fuel injection valve) 7 as a fuel system, an igniter 8 as an ignition system, and an output circuit 26 for outputting to the OCV 10 for adjusting and controlling the oil pressure of the hydraulic oil of the VVT 11. Have been.

Next, a description will be given based on a flowchart of FIG. 3 showing a processing procedure of VVT control in the CPU 21 in the ECU 20 used in the valve timing control device for an internal combustion engine according to one embodiment of the present invention. I do. Note that this VVT control routine is executed every predetermined time.
It is repeatedly executed in U21.

In FIG. 3, first, in step S101,
It is determined whether the idle switch 4 is ON.
When the determination condition of step S101 is satisfied, that is, when the accelerator pedal (not shown) is not depressed and the throttle valve 3 is in the fully closed state, the process proceeds to step S102, and the engine speed NE of the internal combustion engine 1 at this time becomes a predetermined speed. It is determined whether the rotation speed is within the range of not less than the number a and not more than the predetermined rotation number b. Here, the predetermined rotation speed a is set to be higher than the idle rotation speed during the idling operation by a predetermined rotation speed, and the predetermined rotation speed b is set to a rotation speed that is not much higher than the normal rotation speed. When the determination condition of step S102 is satisfied, that is, when the engine speed NE of the internal combustion engine 1 is in a range from the predetermined speed a to the predetermined speed b, the operating state of the internal combustion engine 1 is reduced by the engine brake. The process proceeds to step S103 assuming that the fuel is being cut or the fuel is being cut, and the cleaning operation for the OCV 10 is performed. In the cleaning operation of the OCV 10, a maximum current and a minimum current are alternately supplied to the OCV 10 and a predetermined number of times within a predetermined time are performed so that the displacement amount of a linear solenoid (not shown) of the OCV 10 becomes maximum and minimum. Greatly fluctuated. This allows
For example, even if foreign matter is caught in the OCV 10, it is discharged and removed before the engine speed NE decreases to the idle speed. As described above, when the vehicle is being decelerated by the engine brake of the internal combustion engine 1 or during fuel cut, the engine speed NE is in a stable rotation range where torque fluctuation is unlikely to occur, so that the VVT 11 is accompanied by the cleaning operation of the OCV 10. Even if the movement of the vehicle is slightly unnatural, it does not adversely affect the driving state at this time.

On the other hand, when the condition of step S102 is not satisfied, that is, when the engine speed NE of the internal combustion engine 1 is less than the predetermined speed a and close to the idle speed, the behavior of the VVT 11 causes the internal combustion engine 1 to stall. Or when the engine speed NE is higher than a predetermined speed b, VV
Since the engine speed NE fluctuates due to the behavior of T11, step S103 is skipped, and the cleaning operation for the OCV 10 is not performed. Next, step S104
And the OCT is executed as the most retarded control for the VVT11.
The minimum current is supplied to V10, and this routine ends. Note that as the minimum current for the OCV 10 of this embodiment, VVT11 is, for example, 1 [° CA] near the most retarded end.
(Crank Angle: crank angle)], it is possible to improve the responsiveness of the VVT 11 when the engine speed NE of the internal combustion engine 1 rises from idle operation.

On the other hand, when the determination condition of step S101 is not satisfied, that is, when the idle switch 4 is OFF and the accelerator pedal is depressed, the process proceeds to step S105, and the target advance value based on the operating state of the internal combustion engine 1 is set to It is determined whether it is the maximum. When the determination condition of step S105 is satisfied, that is, when the target advance value is on the maximum maximum advance side, the process proceeds to step S106, and the maximum current is supplied to the OCV 10 as the maximum advance control for the VVT 11, and this routine is executed. finish. In this embodiment, the OCV 10
When the maximum current is applied to the VVT 11, the VVT 11 can be brought into contact with and fixed to the most advanced end, so that a stable most advanced position of the VVT 11 can be obtained.

On the other hand, when the determination condition of step S105 is not satisfied, that is, when the target advance value is not the maximum, the process proceeds to step S107, and an intermediate current suitable for the operation state is supplied to the OCV 10 as intermediate position control for the VVT 11. Then, this routine ends.

As described above, the valve timing control device for an internal combustion engine according to the present embodiment transmits the driving force from the crankshaft 12 as the drive shaft of the internal combustion engine 1 to the camshaft 15 as the driven shaft for opening and closing the intake valve 14. A VVT 11 that is provided in a driving force transmission system that changes the opening and closing timing of the intake valve 14, an OCV 10 that adjusts the hydraulic pressure of hydraulic oil pressurized and supplied to the VVT 11 from an oil pump (not shown), and an internal combustion engine 1. ECU that detects the operating state
Operating state detecting means achieved by the CPU 21 in the CPU 20;
Valve control means achieved by the CPU 21 in the ECU 20 that controls the V10. The valve control means performs a predetermined cleaning operation on the OCV 10 when the internal combustion engine 1 enters a predetermined operation state while the VVT 11 is operating. To do. Further, the valve control means achieved by the CPU 21 in the ECU 20 is assumed to be in a predetermined operating state when the accelerator pedal is not depressed and the engine speed NE is within a predetermined range.

Accordingly, during operation of the VVT 11, the internal combustion engine 1 is brought into a predetermined operating state, the accelerator pedal is not depressed, the throttle valve 3 is fully closed, the idle switch 4 is turned on, and the engine speed NE is increased to a predetermined speed. Number a
As described above, a predetermined cleaning operation is performed on the OCV 10 when the rotational speed is within the range of the predetermined rotational speed b or less. This OC
As the cleaning operation of V10, the maximum current and the minimum current are alternately supplied to the OCV 10 and the OCV 10
Within a predetermined time by a predetermined number of times so that the displacement amount of the linear solenoid becomes maximum and minimum.

As a result, even if the OCV 10 is caught by a foreign substance, it is discharged and removed before the engine speed NE drops to the idle speed. As described above, when the vehicle is decelerating due to the engine brake of the internal combustion engine 1 or during fuel cut, the engine speed NE is in a stable rotation range where torque fluctuation is unlikely to occur.
0, even if the movement of the VVT 11 is slightly unnatural due to the cleaning operation, the abnormality of the VVT 11 is prevented beforehand without adversely affecting the operation state at this time. It is possible to stabilize the idle speed immediately after the time has passed.

Further, the valve timing control apparatus for an internal combustion engine according to the present embodiment transmits a driving force from a crankshaft 12 as a driving shaft of the internal combustion engine 1 to a camshaft 15 as a driven shaft for opening and closing an intake valve 14. A VVT 11 provided in the force transmission system, the opening / closing timing of the intake valve 14 being variable, and an OCV for adjusting the hydraulic pressure of hydraulic oil pressurized and supplied to the VVT 11 from an oil pump (not shown).
10, an operating state detecting means that is achieved by a CPU 21 in an ECU 20 that detects an operating state of the internal combustion engine 1, and an operating state that is achieved by a CPU 21 in the ECU 20 that controls the OCV 10 according to the detection result by the operating state detecting means Valve control means, the valve control means supplying a maximum current to the OCV 10 when the target advance value with respect to the VVT 11 is the maximum maximum advance value as a result of detection by the operating state detection means, When the advance angle value is on the minimum and most retarded side, a minimum current is supplied to the OCV 10.

Therefore, when the target advance angle value for the VVT 11 according to the operating state of the internal combustion engine 1 is the maximum, the maximum current is supplied to the OCV 10 and the VVT 11 is brought into contact with and fixed to the most advanced side. Become. As a result, the VVT 11 has the highest response speed, a small hydraulic pressure loss, and a stable maximum advance position. When the target advance value for the VVT 11 according to the operating state of the internal combustion engine 1 is the minimum, a minimum current is supplied to the OCV 10,
Feedback control is performed so that VVT11 is near the most retarded angle. As a result, the responsiveness of the VVT 11 when the internal combustion engine 1 rises from the idle operation is improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a double overhead cam type internal combustion engine to which a valve timing control device for an internal combustion engine according to one embodiment of the present invention is applied, and peripheral devices thereof.

FIG. 2 is an ECU in the valve timing control device for the internal combustion engine according to one embodiment of the embodiment of the present invention;
FIG. 2 is a block diagram showing an electrical configuration of the inside.

FIG. 3 is a flowchart showing a processing procedure of VVT control in a CPU in an ECU used in a valve timing control device for an internal combustion engine according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 internal combustion engine 4 idle switch 10 OCV (hydraulic control valve) 11 VVT (variable valve timing control mechanism) 12 crankshaft (drive shaft) 13 crank angle sensor 14 intake valve 15 camshaft (driven shaft) 16 cam angle sensor 17 exhaust valve 20 ECU (electronic control unit)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) HE03Z HF10Z 3G301 HA01 HA19 JB02 KA16 KA23 LA07 LB02 LC08 MA24 ND41 NE11 NE12 NE23 PA07Z PA14Z PE01Z PE03Z PE10A PE10B PE10Z

Claims (3)

[Claims] An opening / closing timing of the intake valve or the exhaust valve is provided in a driving force transmission system that transmits a driving force from a driving shaft of an internal combustion engine to a driven shaft that opens and closes at least one of an intake valve and an exhaust valve. A variable valve timing control mechanism that can change the pressure, a hydraulic control valve that adjusts the oil pressure of hydraulic oil pressurized and supplied from an oil pump to the variable valve timing control mechanism, and an operation state detection that detects an operation state of the internal combustion engine Means, and valve control means for controlling the hydraulic control valve in accordance with the detection result by the operating state detection means, wherein the valve control means controls the internal combustion engine to operate at a predetermined speed while the variable valve timing control mechanism is operating. An internal combustion engine that performs a predetermined cleaning operation on the hydraulic control valve when the operating state is reached. Use the valve timing control apparatus. 2. The internal combustion engine according to claim 1, wherein the valve control means sets the predetermined operating state when the accelerator pedal is not depressed and the engine speed is within a predetermined range. Engine valve timing control device. 3. A drive force transmission system for transmitting a drive force from a drive shaft of an internal combustion engine to a driven shaft that opens and closes at least one of an intake valve and an exhaust valve, the opening and closing timing of the intake valve or the exhaust valve. A variable valve timing control mechanism that can change the pressure, a hydraulic control valve that adjusts the oil pressure of hydraulic oil pressurized and supplied from an oil pump to the variable valve timing control mechanism, and an operation state detection that detects an operation state of the internal combustion engine Means, and valve control means for controlling the hydraulic control valve in accordance with the detection result by the operation state detection means, wherein the valve control means controls the variable valve timing control mechanism based on the detection result by the operation state detection means. When the target advance value with respect to the maximum advance angle, the maximum current is supplied to the hydraulic control valve. The internal combustion engine valve timing control apparatus characterized by energizing the minimum current to the hydraulic control valve when the target advance value is the minimum of the most delayed angle side.