JPH08200135A - Controller for internal combustion engine - Google Patents

Abstract

PURPOSE: To prevent a valve from being damaged and exhaust gas properties from being deteriorated by detecting the actual one opening and closing valve timing of intake and exhaust valves to be driven by an electromagnetic driving means, judging abnormalities of the electromagnetic driving means according to the compared result of the detected opening/closing valve timing with the specified limit timing, and accurately judging the deviation of the timing of the intake valve and the exhaust vale. CONSTITUTION: Limit values on an opening valve side and a closing valve side are determined by referring to a map set according to the accelerator opening and the engine speed. The actual valve opening and closing operation starting timing of a valve element 2 is detected by output of a position sensor 11. The valve opening and closing operation starting timing is compared with the limit values on the valve opening and closing sides. When the valve opening operation starting timing exists on the advance side from the valve opening limit value, or when the valve closing operation starting timing exists on the delay side from the valve closing side limit value, the limit check NG is judged. When the NG is judged, an abnormality judging is flagged, an intake/exhaust valve of the corresponding cylinder is closed, and the fuel supply to the corresponding cylinder is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine having an electromagnetically driven intake valve and / or exhaust valve.

[0002]

2. Description of the Related Art The basic construction of an internal combustion engine in which an intake valve and / or an exhaust valve are driven by a spring and a solenoid is shown in U.S. Pat. No. 3,882,833. Furthermore, as a control device for an internal combustion engine that employs such a basic configuration, a control device that changes the output timing of a drive signal supplied to a valve drive solenoid in accordance with the engine speed has been conventionally known ( JP-A-2-112
No. 606).

Further, in the above basic structure, there has been proposed a solenoid valve in which the structure of the electromagnetic drive mechanism is improved in order to reduce the required electromagnetic force of the solenoid as much as possible (US Pat. No. 5,222,714). ).

[0004]

However, none of the above-mentioned conventional techniques has a function of determining abnormality of the electromagnetic drive mechanism of the intake valve and / or the exhaust valve. For example, opening / closing of the intake valve or the exhaust valve. There is a risk that the intake valve or the exhaust valve may come into contact with the piston due to the timing deviation, or the fuel supplied to the combustion chamber may be discharged as it is, and the exhaust gas characteristics may be deteriorated.

The present invention has been made in view of this point, and determines abnormality of an electromagnetically driven intake valve and / or an exhaust valve, and damages or exhausts the intake valve or the exhaust valve due to, for example, opening / closing timing deviation. An object of the present invention is to provide a control device for an internal combustion engine that can prevent deterioration of gas characteristics.

[0006]

To achieve the above object, the present invention provides an electromagnetic drive means for opening and closing at least one of an intake valve and an exhaust valve of an internal combustion engine by an electromagnetic force, and an accelerator for a vehicle on which the engine is mounted. An accelerator pedal depression amount detecting means for detecting a pedal depression amount, an engine operating state detecting means for detecting an engine operating state including at least the engine speed, and a fuel supply means for supplying fuel to the engine are provided. In a control device for an internal combustion engine, the opening / closing valve timing of at least one of an intake valve and an exhaust valve by the electromagnetic driving means is calculated according to the detected accelerator pedal depression amount and engine operating state, and the opening / closing timing is calculated according to the calculated opening / closing timing. Valve opening / closing control means for controlling the electromagnetic drive means,
The actual opening / closing valve timing detecting means for detecting the actual opening / closing valve timing of at least one of the intake valve and the exhaust valve by the valve opening / closing control means is compared with the detected opening / closing valve timing and a predetermined limit timing, and the comparison is made. An abnormality determining means for determining an abnormality of the electromagnetic driving means based on the result is provided.

When it is determined that the electromagnetic drive means is abnormal, the valve opening / closing control means regulates at least one of the intake valve and the exhaust valve to a closed state, and the fuel supply means supplies fuel. It is desirable to stop.

[0008]

According to the control device of the present invention, the actual opening / closing valve timing of at least one of the intake valve and the exhaust valve driven by the electromagnetic drive means is detected, and the detected opening / closing valve timing and the predetermined limit timing are set. The abnormality of the electromagnetic drive means is determined according to the comparison result of.

According to the control device of the second aspect, when it is determined that the electromagnetic drive means is abnormal, at least one of the electromagnetically driven intake valve and exhaust valve is restricted to the closed state, and the fuel is supplied. Is stopped.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an electromagnetically driven intake valve 10 according to an embodiment of the present invention. This intake valve 1
Reference numeral 0 denotes a valve body 2 to which an armature 4 is fixed and a valve drive unit 1 for driving the armature 4, which is mounted on the upper portion of the combustion chamber via a valve guide 3 in order to open and close an intake port 8 of the combustion chamber of the internal combustion engine. To be done. An exhaust valve (not shown) also has the same structure and is attached to the upper portion of the combustion chamber to open and close the exhaust port of the combustion chamber.

The valve drive unit 1 has two solenoids (electromagnets) facing each other, that is, a valve closing solenoid 5 for urging the valve body 2 in the valve closing direction and a valve opening solenoid 6 for urging the valve body 2 in the valve opening direction. And the spring 7 as main constituent elements.
The valve closing solenoid 5 is composed of a coil 5a and a magnetic body 5b, and the valve opening solenoid 6 is composed of a coil 6a and a magnetic body 6b. In the spring 7, the armature 4 is in the neutral position BP.
The biasing force against the valve element 2 becomes zero when the valve is in the position, the valve element 2 is biased in the valve opening direction when the valve element 2 is positioned above the neutral position BP, and the valve element 2 is pressed when the valve position is positioned below the neutral position BP. It is configured to urge in the valve closing direction.

According to the above construction, by energizing the valve closing solenoid 5 or the valve opening solenoid 6, the valve body 2 closes the intake port 8 in the fully closed position and the valve body 2 in the fully opened position where the lift amount is maximized. Move between and. When the solenoids 5 and 6 are not energized, the valve body 2 is located at the neutral position between the fully closed position and the fully open position.

FIG. 2 is a diagram showing the construction of the intake valve 10 and its control device. The valve drive unit 1 has an armature 4 as shown in FIG.
Position sensor 11 for detecting the position of the valve and the valve opening solenoid 6
A temperature sensor 12 for detecting the temperature TCOIL of the coil is provided, and these detection signals are supplied to the CPU (central processing unit) 16 and the energization time / timing control circuit unit 14 via the input / output interface 13. A sensor group (not shown) is further connected to the input / output interface 13, and the engine speed NE, the accelerator pedal depression amount (hereinafter referred to as “accelerator opening degree”) θACC of the vehicle equipped with the engine θACC, and the engine water temperature TW. , Intake air temperature TA, signal indicating battery voltage VB, etc., signal indicating crankshaft rotation angle, signal indicating ON / OFF of ignition switch, etc., and these signals are supplied to the CPU 16 and energization time / timing control circuit unit 14. To be done.
In this embodiment, as a signal indicating the rotation angle of the crankshaft, a signal pulse indicating a predetermined crank angle position of a specific cylinder of the engine (hereinafter referred to as "CYL signal pulse",
One pulse is generated for every 720 ° of crank angle) and a signal pulse (hereinafter, referred to as “CRK signal pulse”) generated at a cycle of 30 ° of crank angle is input.

The CPU 16 is connected to a ROM 17 for storing programs executed by the CPU 16 and a RAM 18 for storing data during calculation and sensor detection data. Further, a timer counter 19 having a function as a timer is connected to the energization time / timing control circuit unit 14, and the timer counter 19 is C
It is connected to the PU16 and its count value setting is C
It is performed by the PU 16.

The energization time / timing control circuit section 14 is connected to the driver circuit 15, and the valve closing solenoid drive circuit 15a of the driver circuit 15 is connected to the coil 5 of the valve closing solenoid 5.
The valve-opening solenoid drive circuit 15b is connected to the coil 6a of the valve-opening solenoid 6, respectively. A battery 20 is connected to the driver circuit 15, and electric power is supplied from the battery 20. The control circuit unit 14 controls current supply (energization) to the coils 5a and 6a.

The CPU 1 other than the driver circuit 15
6, a power supply voltage is supplied to the other circuits such as the ROM 17, the input / output interface 13, and the like from the battery 20 via a power supply circuit (not shown).

The engine of this embodiment is a four-cylinder engine in which each cylinder is provided with two intake valves and two exhaust valves, and a total of 16 valves are electromagnetically driven. There is. Therefore, the energization time / timing control circuit unit 4, the driver circuit 15, and the timer counter 19 in FIG.
It is provided corresponding to each of the 16 valves.

The CPU 16 determines the opening timing, closing timing, etc. of the intake valve and the exhaust valve according to input signals from various sensors, and sets the timer counter 19 corresponding to each intake and exhaust valve.

Further, a fuel injection valve (not shown) is provided for each cylinder in the intake pipe of the engine of this embodiment. The valve opening control of this fuel injection valve and the ignition of the ignition plug of each cylinder are performed. The output control of the command signal is configured to be performed by the CPU 16.

FIG. 3 is a flow chart of an intake / exhaust valve opening / closing control routine executed by the CPU 16.
FIG. 4 is a diagram for explaining the relationship between the valve lift amount of the intake and exhaust valves and the voltage applied to the valve opening solenoid 6 and the valve closing solenoid 5. First, an outline of energization control of each solenoid will be described with reference to FIG.

In the present embodiment, when the intake / exhaust valve is opened, the energization of the valve closing solenoid 5 is completed (θCLOSEO).
FF) before the first overlap period A (θO
PENON) starts energizing the valve opening solenoid 6. As a result, the valve body 2 starts the valve opening operation, and when the energization of the valve closing solenoid 5 is completed, the valve element 2 moves to the fully opened position quickly and reliably. Further, during the valve closing operation, the energization of the valve closing solenoid 5 is started at the time point (θCLOSEON) before the second overlap period B before the end of the energization of the valve opening solenoid 6 (θOPENOFF). As a result, the valve body 2 starts the valve closing operation, and when the energization of the valve opening solenoid 5 is completed,
Moves to the fully closed position quickly and reliably.

Next, a specific method of calculating the energization start / end timing of each solenoid will be described with reference to FIG.

In step S1 of FIG. 3, it is determined whether or not an abnormality determination flag FEVAFS (N) is "1", which indicates by "1" that the intake / exhaust valve opening / closing operation timing is determined to be abnormal. This abnormality determination flag FEVAFS (N) is set for each cylinder in the abnormality determination routine of FIG. 9 described later, and (N) is attached to indicate that it is a flag set for each cylinder. .

If FEVAFS (N) = 1 in step S1 and it is determined that there is an abnormality in the opening / closing timing of the intake valve or the exhaust valve of the Nth cylinder, the intake valve and the exhaust valve of the Nth cylinder are closed. A valve command signal is output (step S2), and this routine ends. At the same time, the control for stopping the fuel supply to the corresponding cylinder is performed.

If the answer to step S1 is negative (NO), that is, FEVAFS (N) = 0, step S3 is performed.
And the energization end timing of the valve closing solenoid 5 θCLOSE
OFF, accelerator opening θACC and engine speed N
It is calculated by searching the map set according to E. Next, the energization start timing θOP of the valve opening solenoid 6
ENON is calculated by the following formula (step S4).

ΘOPENON = θCLOSEOFF-A Here, as shown in FIG. 5, the first overlap period A is set according to the engine speed NE and the coil temperature TCOIL (specifically, the NE value and the TCOIL. Calculated by searching the map set according to the value).

In the following step S5, as in step S3, the energization end timing θOPENOF of the valve opening solenoid 6 is reached.
F is calculated by searching a map set according to the accelerator opening θACC and the engine speed NE. Next, the energization start timing θCLO of the valve closing solenoid 5
SEON is calculated by the following formula.

ΘCLOSEON = θOPENOFF−B Here, the second overlap period B is as shown in FIG.
Similar to the first overlap period A, it is set according to the engine speed NE and the coil temperature TCOIL by map search.

Next, the intake / exhaust valve opening / closing valve timing correction routine (step S7) and the opening / closing valve solenoid energization processing routine (step S8) are executed, and this processing ends.

FIG. 6 is a flow chart of the intake / exhaust valve opening / closing valve timing correction routine. First, in step S11, the coil temperature TCOIL and the battery voltage VB are read, and then the valve closing solenoid 5 and the valve opening solenoid 6 are read.
The energization start / end timing of is corrected according to the coil temperature TCOIL and the battery voltage VB (step S12).
Specifically, as shown in FIG. 7, the energization start / end timing of each solenoid is corrected such that the higher the coil temperature TCOIL and the lower the battery voltage VB, the more advanced the side.

FIG. 8 is a flow chart of the on-off valve solenoid energization processing routine in step S8 of FIG. 3, and this routine carries out the actual energization processing according to the calculated energization start / end timing of each solenoid. At this time, the intake valve and the exhaust valve to be opened are the intake valve of the cylinder in the intake stroke and the exhaust valve of the cylinder in the exhaust stroke, respectively.

First, the energization start timing θO of the valve opening solenoid 6
It is determined whether or not it is PENON (step S21),
When the answer is affirmative (YES), energization of the valve opening solenoid 6 is started (step S23), and then it is determined whether or not the energization end timing θCLOSEOFF of the valve closing solenoid 5 is reached (step S23). When the determination is affirmative (YES), the energization of the valve closing solenoid 5 is terminated (step S2
4), then the energization start timing of the valve closing solenoid 5 θCLO
Whether or not it is SEON is determined (step S25), and when the answer is affirmative (YES), energization of the valve closing solenoid 5 is started (step S26), and then the valve opening solenoid 6 is opened.
It is determined whether or not the energization end timing θOPENOFF of (step S27), and when the answer is affirmative (YES), the energization of the valve opening solenoid 6 is terminated (step S28).

When the power supply start / end timing does not apply, this process is immediately terminated.

FIG. 9 is a flowchart of a routine for determining an abnormality in the opening / closing operation timing of the intake / exhaust valve.

First, in step S31, the accelerator opening θ
A map set according to the ACC and the engine speed NE is searched to determine the valve opening side limit value θLMTOPEN and the valve closing side limit value θLMTCLOSE. Next, based on the output of the position sensor 11, the actual valve opening operation start timing θACTOPEN and the valve closing operation start timing θA of the valve body 2 are outputted.
CTCLOSE (see FIG. 4A) is detected (step S32). In the following step S33, the detection timing θAC
Limit check of TOPEN and θACTCLOSE.

Specifically, the valve opening operation start timing θACTO
The PEN and the valve opening operation start timing θACTCLOSE are compared with the valve opening side limit value θLMTOPEN and the valve closing side limit value θLMTCROSE, respectively, and θACTOPE
When the N value is on the advance side of the θLMTOPEN value, or when the θACTCLOSE value is on the retard side of the θLMTCLOSE value, it is determined that the limit check is NG (FIG. 4).
(See the broken line in (a)).

When the limit check is OK, this routine is immediately terminated, while when it is NG, the abnormality determination flag FEVFAFS (N) is set to "1" (step S34), and this routine is terminated.

According to this routine, it is possible to accurately determine the deviation of the opening / closing timing of the intake / exhaust valve, which is caused by deterioration or failure of the intake / exhaust valve and the drive system thereof.

Further, in this embodiment, when it is determined that the opening / closing timing of the intake / exhaust valve is abnormal, the intake / exhaust valve of the corresponding cylinder is closed and the fuel supply to the corresponding cylinder is stopped. It is possible to prevent damage due to contact between the intake / exhaust valve and the piston, and to prevent blowout of unburned gas, thereby suppressing deterioration of exhaust gas characteristics.

In the embodiment described above, the flag FEVAFS (N) = 1 is discriminated in step S1 of FIG. 3 to control the intake / exhaust valve of only the cylinder concerned to be closed, and the fuel supply to the cylinder concerned is stopped. However, either the flag FEVAFS (N) = 1 of one of the cylinders is determined, or the flag FEVAFF of a predetermined number of cylinders (for example, two) or more is used.
It may be determined that S (N) = 1 and the intake / exhaust valves of all cylinders may be controlled to be closed and the fuel supply to all cylinders may be stopped.

[0042]

As described in detail above, according to the control device of the first aspect, the actual opening / closing valve timing of at least one of the intake valve and the exhaust valve driven by the electromagnetic drive means is detected, and the detected opening / closing timing is detected. Since the abnormality of the electromagnetic drive means is determined according to the comparison result of the valve timing and the predetermined limit timing, the deviation of the opening / closing valve timing of the intake valve and / or the exhaust valve due to the abnormality of the electromagnetic drive means is accurately determined. be able to.

According to the control device of the second aspect, when it is determined that the electromagnetic drive means is abnormal, at least one of the electromagnetically driven intake valve and exhaust valve is regulated to the closed state, and the fuel is supplied. Since it is stopped, damage due to contact between the intake valve and / or the exhaust valve and the piston, etc. can be prevented, blown-through of unburned gas can be prevented, and deterioration of exhaust gas characteristics can be suppressed.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an electromagnetically driven intake valve according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an intake valve and its control device in FIG.

FIG. 3 is a flowchart of an intake / exhaust valve opening / closing control routine.

FIG. 4 is a diagram for explaining a relationship between a drive signal of an intake / exhaust valve and a valve lift amount.

FIG. 5 is a diagram for explaining a setting tendency of an overlap period (A, B) calculation map.

FIG. 6 is a flowchart of an intake / exhaust valve opening / closing valve timing correction routine.

FIG. 7 is a diagram showing a tendency of correction of opening / closing valve timing.

FIG. 8 is a flowchart of an on-off valve solenoid energization processing routine.

FIG. 9 is a flowchart of an abnormality determination routine.

[Explanation of symbols]

 1 Valve Drive 5 Closed Solenoid 6 Opened Solenoid 7 Spring 10 Intake Valve 11 Position Sensor 12 Coil Temperature Sensor 16 CPU

Claims (2)

[Claims] 1. An electromagnetic drive means for opening and closing at least one of an intake valve and an exhaust valve of an internal combustion engine by an electromagnetic force, and an accelerator pedal depression amount detecting means for detecting an accelerator pedal depression amount of a vehicle on which the engine is mounted. , An internal combustion engine control device comprising an engine operating state detecting means for detecting an engine operating state including at least the number of revolutions of the engine, and a fuel supply means for supplying fuel to the engine, wherein the detected accelerator pedal depression amount And valve opening / closing control means for calculating the opening / closing valve timing of at least one of the intake valve and the exhaust valve by the electromagnetic driving means according to the engine operating state, and controlling the electromagnetic driving means according to the calculated opening / closing timing, An actual opening / closing valve timing detecting means for detecting an actual opening / closing valve timing of at least one of the intake valve and the exhaust valve by the valve opening / closing control means; Compare the detected on-off valve timing with a predetermined limit timing,
A control device for an internal combustion engine, comprising: abnormality determination means for determining abnormality of the electromagnetic drive means based on the comparison result. 2. When it is determined that the electromagnetic drive means is abnormal, the valve opening / closing control means regulates at least one of the intake valve and the exhaust valve to a closed state, and the fuel supply means supplies fuel. 2. The control device for the internal combustion engine according to claim 1, wherein the control unit stops.