JP2002227673A - Control device for electromagnetically driven valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the flexibility of controlling the amounts of torque and secondary air of an internal combustion engine in a technology for supplying the secondary air to an exhaust emission control catalyst disposed in the exhaust passage of the engine. SOLUTION: The objective control device for an electromagnetically driven valve is provided with an exhaust emission control catalyst disposed in the exhaust passage of an internal combustion engine, an electromagnetically driving valve mechanism for driving at least one of the intake and exhaust valves to open or close by using an electromagnetic force, and a valve mechanism control means for controlling the above valve mechanism when supplying a secondary air to the exhaust emission control catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for activating an exhaust purification catalyst disposed in an exhaust passage of an internal combustion engine.
In particular, the present invention relates to a technique for supplying secondary air to an exhaust purification catalyst to promote activation of the exhaust purification catalyst.

[0002]

2. Description of the Related Art In recent years, in an internal combustion engine mounted on an automobile or the like, when an unburned fuel component contained in exhaust gas becomes relatively large, such as during a warm-up operation after a cold start, an exhaust purification catalyst is used. By supplying secondary air to the exhaust passage more upstream,
A technique has been proposed in which an unburned fuel component is reacted with oxygen in secondary air by an exhaust purification catalyst to purify the unburned fuel component and promote a catalytic reaction.

As a method of supplying secondary air to an exhaust passage upstream of an exhaust purification catalyst, a method of adding an air pump to an exhaust system of an internal combustion engine is conceivable. However, since the structure of the exhaust system becomes complicated, it is mounted on a vehicle. There is a problem such as deterioration of properties.

In order to solve such a problem, conventionally, for example, a "control device for an engine equipped with an electrically heated catalyst" as described in Japanese Patent Application Laid-Open No. 10-220220 is disclosed.
Has been proposed.

The control apparatus for an engine provided with an electrically heated catalyst described in the above-mentioned publication discloses a warm-up after a cold start of an internal combustion engine in a multi-cylinder engine having an electrically heated catalyst in an exhaust passage. When power is supplied to the electric heating catalyst such as at the time, the fuel injection to some of the cylinders of the multi-cylinder engine is stopped, and the intake air is directly discharged from some of the cylinders, whereby Is configured to supply the intake air discharged from the cylinder as secondary air to the electrically heated catalyst.

That is, the control device for an engine having the above-described electrically heated catalyst stops the operation of some of the cylinders of the multi-cylinder engine when supplying the secondary air to the electrically heated catalyst. It is intended to supply secondary air to the electrically heated catalyst without adding an air pump or the like.

[0007]

In the prior art as described above, the secondary air is supplied to the exhaust purification catalyst simply by stopping the fuel injection to some of the cylinders of the multi-cylinder engine. There is a problem that the degree of freedom in controlling the torque of the engine and the amount of secondary air is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the operation state of the internal combustion engine and the supply of secondary air to an exhaust purification catalyst disposed in an exhaust passage of the internal combustion engine. It is an object of the present invention to provide a technique capable of increasing the degree of freedom in controlling the amount of secondary air and the like.

[0009]

The present invention employs the following means to solve the above-mentioned problems.

That is, a control device for an electromagnetically driven valve according to the present invention utilizes an electromagnetic force for an exhaust purification catalyst provided in an exhaust passage of an internal combustion engine and at least one of an intake valve and an exhaust valve of the internal combustion engine. An electromagnetically driven valve operating mechanism for opening and closing, and when supplying secondary air to the exhaust purification catalyst, a valve operating mechanism control means for controlling the electromagnetically driven valve operating mechanism;
It is characterized by having.

In the control apparatus for an electromagnetically driven valve configured as described above, when the secondary air is supplied to the exhaust purification catalyst disposed in the exhaust passage of the internal combustion engine, the valve mechanism control means uses the electromagnetically driven valve control. By controlling the mechanism, the degree of freedom of control relating to the secondary air supply is increased.

For example, when the secondary air is supplied to the exhaust purification catalyst by reducing the fuel injection amount to a predetermined cylinder of the internal combustion engine, the valve mechanism control means determines that the torque of the internal combustion engine is equal to the predetermined target torque. The electromagnetically driven valve operating mechanisms of cylinders other than the predetermined cylinder may be controlled so as to match.

When the secondary air is supplied to the exhaust gas purifying catalyst by reducing the fuel injection amount to a predetermined cylinder of the internal combustion engine, the valve mechanism control means may reduce the number of strokes of the predetermined cylinder. The electromagnetically driven valve mechanism of a predetermined cylinder may be controlled. In this case, the number of strokes per cycle decreases, so that the amount of secondary air discharged from the predetermined cylinder can be increased.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a control device for an electromagnetically driven valve according to the present invention.

FIGS. 1 and 2 are views showing an embodiment of an internal combustion engine to which the present invention is applied and an intake / exhaust system thereof. The internal combustion engine 1 shown in FIGS. 1 and 2 has four cylinders 21.
It is a stroke cycle water-cooled gasoline engine.

The internal combustion engine 1 includes a cylinder block 1b in which four cylinders 21 and a cooling water passage 1c are formed, and a cylinder head 1 fixed on an upper portion of the cylinder block 1b.
a.

The cylinder block 1b rotatably supports a crankshaft 23, which is an engine output shaft. Connected.

A timing rotor 51a having a plurality of teeth formed on a peripheral edge is attached to an end of the crankshaft 23, and an electromagnetic pickup 51b is attached to a cylinder block 1b near the timing rotor 51a. The timing rotor 51a and the electromagnetic pickup 51b constitute a crank position sensor 51.

A water temperature sensor 52 for outputting an electric signal corresponding to the temperature of the cooling water flowing in the cooling water passage 1c is attached to the cylinder block 1b.

Above the piston 22 of each cylinder 21, a combustion chamber 24 surrounded by the top surface of the piston 22 and the wall surface of the cylinder head 1a is formed. The cylinder head 1
a includes spark plugs 25 facing the combustion chamber 24 of each cylinder 21.
The ignition plug 25 is electrically connected to an igniter 25a for applying a drive current to the ignition plug 25.

In the cylinder head 1a, each cylinder 2
Two open ends of the intake port 26 and two open ends of the exhaust port 27 are formed at a portion facing one combustion chamber 24. And the cylinder head 1
In a, an intake valve 28 for opening and closing each open end of the intake port 26 and an exhaust valve 29 for opening and closing each open end of the exhaust port 27 are provided to be able to move forward and backward.

An electromagnetic drive mechanism 30 for driving the intake valve 28 forward and backward by using an electromagnetic force generated when an excitation current is applied to the cylinder head 1a (hereinafter referred to as an intake-side electromagnetic drive mechanism 30). Are provided in the same number as the intake valves 28. Each intake side electromagnetic drive mechanism 30 has a drive circuit 30 for applying an exciting current to the intake side electromagnetic drive mechanism 30.
a (hereinafter referred to as an intake-side drive circuit 30a) is electrically connected.

An electromagnetic drive mechanism 31 for driving the exhaust valve 29 forward and backward using an electromagnetic force generated when an exciting current is applied to the cylinder head 1a (hereinafter referred to as an exhaust-side electromagnetic drive mechanism 31). Are provided in the same number as the exhaust valves 29. Each exhaust-side electromagnetic drive mechanism 31 has a drive circuit 31 for applying an exciting current to the exhaust-side electromagnetic drive mechanism 31.
a (hereinafter, referred to as an exhaust-side drive circuit 31a) is electrically connected.

Here, a specific configuration of the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 will be described.
The intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31
Since the configuration is the same as that described above, only the intake-side electromagnetic drive mechanism 30 will be described as an example.

FIG. 3 is a sectional view showing the structure of the intake side electromagnetic drive mechanism 30. In FIG. 3, the cylinder head 1a of the internal combustion engine 1 includes a lower head 10 fixed to the upper surface of the cylinder block 1b, and an upper head 11 provided on the lower head 10.

The lower head 10 is formed with two intake ports 26 for each cylinder 21, and a valve body 28 a of an intake valve 28 is seated at an open end of each intake port 26 on the combustion chamber 24 side. A valve seat 12 is provided.

Each of the lower heads 10 has an intake port 2.
A through-hole having a circular cross section is formed from the inner wall surface of 6 to the upper surface of the lower head 10, and a cylindrical valve guide 13 is inserted into the through-hole. A valve shaft 28b of the intake valve 28 penetrates through an inner hole of the valve guide 13, and the valve shaft 2
8b is slidable in the axial direction.

A portion of the upper head 11 having the same axis as the valve guide 13 is provided with a first core 30.
A core mounting hole 14 having a circular cross section into which the first and second cores 302 are fitted is provided. Lower part 1 of core mounting hole 14
4b is formed larger in diameter than its upper part 14a. Hereinafter, the lower part 14b of the core mounting hole 14 is referred to as a large diameter part 14b, and the upper part 14a of the core mounting hole 14 is referred to as a small diameter part 14a.

An annular first core 301 and a second core 302 made of a soft magnetic material are fitted in the small-diameter portion 14a in series in the axial direction with a predetermined gap 303 therebetween. At the upper end of the first core 301 and the lower end of the second core 302,
A flange 301a and a flange 302a are respectively formed, and the first core 301 is provided from above and the second core 3a.
The first core 301 and the second core 3 are respectively inserted into the core mounting holes 14 from below, and the flanges 301a and 302a abut against the edges of the core mounting holes 14.
02 is positioned, and the gap 303 is maintained at a predetermined distance. An annular upper plate 318 is disposed above the first core 301, and a flange 305a having an outer diameter substantially the same as that of the upper plate 318 is provided at the lower end of the cylindrical body above the upper plate 318. Formed formed upper cap 30
5 are arranged.

The upper cap 305 and the upper plate 318 are connected to the flange 3 of the upper cap 305.
It is fixed to the upper surface of the upper head 11 by a bolt 304 that penetrates from the upper surface of the upper head 05a to the inside of the upper head 11 via the upper plate 318.

In this case, the lower end of the upper cap 305 including the flange 305a contacts the upper surface of the upper plate 318, and the lower surface of the upper plate 318 Upper head 1 in contact with
1 and as a result, the first core 301
Is fixed to the upper head 11.

Below the second core 302, there is provided a lower plate 307 made of an annular body having an outer diameter substantially the same as the large diameter portion 14b of the core mounting hole 14. The lower plate 307 is fixed to a downward step surface in the step portion of the small diameter portion 14a and the large diameter portion 14b by a bolt 306 penetrating from the lower surface of the lower plate 307 to the upper head 11. In this case, the lower plate 307 is fixed while being in contact with the lower peripheral edge of the second core 302, and as a result, the second core 302 is fixed to the upper head 11.

A first electromagnetic coil 308 is held in a groove formed on the surface of the first core 301 on the gap 303 side, and formed on a surface of the second core 302 on the gap 303 side. The second electromagnetic coil 309 is held in the groove. At this time, the first electromagnetic coil 308 and the second electromagnetic coil 309 are arranged at positions facing each other via the gap 303. The first and second electromagnetic coils 308 and 309 are electrically connected to the above-described intake side drive circuit 30a.

The gap 303 has an armature 31 formed of an annular body having an outer diameter smaller than the inner diameter of the gap 303.
1 is arranged. The armature 311 is formed of, for example, a soft magnetic material.

In the hollow portion of the armature 311, an armature shaft 310 made of a columnar non-magnetic material having an outer diameter smaller than the hollow portions of the first core 301 and the second core 302 is provided. It is fixed so as to extend vertically along the axis.

At this time, the armature shaft 310
Has its upper end reaching through the hollow portion of the first core 301 into the upper cap 305 above it, and its lower end passing through the hollow portion of the second core 302 into the large diameter portion 14b below it. It is formed as follows.

Correspondingly, each of the upper end of the hollow portion of the first core 301 and the lower end of the hollow portion of the second core 302 has an inner diameter substantially the same as the outer diameter of the armature shaft 310. An annular upper bush 319 and a lower bush 320 are provided.
The armature shaft 310 is slidably held in the axial direction by the lower bush 320 and the armature shaft 310.

A disc-shaped upper retainer 312 is joined to the upper end of the armature shaft 310 extending into the upper cap 305, and an adjust bolt 313 is screwed into the upper opening of the upper cap 305. An upper spring 314 is interposed between the upper retainer 312 and the adjustment bolt 313. A spring seat 315 having an outer diameter substantially equal to the inner diameter of the upper cap 305 is interposed on a contact surface between the adjust bolt 313 and the upper spring 314.

At the lower end of the armature shaft 310 extending into the large diameter portion 14b, a valve shaft 28b of the intake valve 28 is provided.
Is in contact with the upper end. A disc-shaped lower retainer 28c is joined to the outer periphery of the upper end of the valve shaft 28b. A lower spring 316 is interposed between the lower surface of the lower retainer 28c and the upper surface of the lower head 10.

In the intake-side electromagnetic drive mechanism 30 configured as described above, when no excitation current is applied from the intake-side drive circuit 30a to the first electromagnetic coil 308 and the second electromagnetic coil 309, the upper Downward from the spring 314 relative to the armature shaft 310 (ie,
An urging force acts on the intake valve 28 (in a direction to open the intake valve 28), and an urging force acts on the intake valve 28 from the lower spring 316 in an upward direction (ie, a direction in which the intake valve 28 closes). As a result, the armature shaft 310
In addition, the state where the intake valve 28 abuts with each other and is elastically supported at a predetermined position, that is, a so-called neutral state is maintained.

The biasing force of the upper spring 314 and the lower spring 316 is set so that the neutral position of the armature 311 is located at an intermediate position between the first core 301 and the second core 302 in the gap 303. If the neutral position of the armature 311 is deviated from the above-described intermediate position due to an initial tolerance or a secular change of a component, the neutral position of the armature 311 is adjusted by the adjustment bolt 313 so as to match the above-described intermediate position. Has become possible.

The length of the armature shaft 310 and the valve shaft 28b in the axial direction is such that when the armature 311 is located at an intermediate position of the gap 303,
a becomes a middle position between the valve-opening-side displacement end and the valve-closing-side displacement end (hereinafter, referred to as a middle-open position), and when the armature 311 contacts the first core 301, the valve body 28
a is set to be seated on the valve seat 12.

In the above-described intake-side electromagnetic drive mechanism 30, when an excitation current is applied to the first electromagnetic coil 308 from the intake-side drive circuit 30a, the first core 301 and the first electromagnetic coil 308 are connected to each other. Since an electromagnetic force is generated between the armature 311 and the armature 311 to displace the armature 311 toward the first core 301, the armature 311 contacts the first core 301 against the urging force of the upper spring 314. Become.

When the armature 311 is in contact with the first core 301, the intake valve 28
6. The valve body 28a of the intake valve 28 retreats under the biasing force of
Is seated on the valve seat 12, that is, a fully closed state.

In the intake side electromagnetic drive mechanism 30, the second electromagnetic coil 309 is provided from the intake side drive circuit 30a.
When the exciting current is applied to the second core 30
Since an electromagnetic force is generated between the second and second electromagnetic coils 309 and the armature 311 in the direction of displacing the armature 311 toward the second core 302, the armature 311 resists the urging force of the lower spring 316. The two cores 302 come into contact with each other.

When the armature 311 is in contact with the second core 302, the armature shaft 310 presses the valve shaft 28b in the valve opening direction against the urging force of the lower spring 316, and the pressing force is applied. By the intake valve 28
Is held in the fully open state.

In the above-described intake-side electromagnetic drive mechanism 30, when the intake valve 28 in the fully closed state is opened, the intake-side drive circuit 30a first stops applying the exciting current to the first electromagnetic coil 308. I do.

At this time, since the electromagnetic force for attracting the armature 311 to the first core 301 between the first core 301, the first electromagnetic coil 308, and the armature shaft 310 disappears, the armature 311 and the intake valve 28 are connected to the upper spring. The valve 314 is displaced in the valve opening direction by receiving the urging force of 314.

The intake side drive circuit 30a includes an armature 31
When the first electromagnetic coil 3 is displaced to the vicinity of the second core 302 by receiving the urging force of the upper spring 314, the second electromagnetic coil 3
By applying an exciting current to the second coil 302, an electromagnetic force that attracts the armature 311 to the second core 302 is generated between the second core 302, the second electromagnetic coil 309, and the armature 311. Armature 31 by this electromagnetic force
1 is displaced to a position where it comes into contact with the second core 302 (valve opening side displacement end), and as a result, the intake valve 28 is fully opened.

On the other hand, in the above-described intake side electromagnetic drive mechanism 30, when closing the intake valve 28 in the fully open state, the intake side drive circuit 30a first stops applying the exciting current to the second electromagnetic coil 309. .

At this time, since the electromagnetic force for attracting the armature 311 to the second core 302 between the second core 302, the second electromagnetic coil 309, and the armature shaft 310 disappears, the armature 311 and the intake valve 28 are connected to the lower spring. It is displaced in the valve closing direction by receiving the urging force of 316.

The intake side drive circuit 30a includes an armature 31
The first core 3 receives the urging force of the lower spring 316
01, the first electromagnetic coil 30
8 by applying an exciting current to the first core 3.
01, the first electromagnetic coil 308, and the armature 311, an electromagnetic force for attracting the armature 311 to the first core 301 is generated. Armature 31 by this electromagnetic force
1 is displaced to a position where it comes into contact with the first core 301 (displacement end on the valve closing side). As a result, the valve body 28a of the intake valve 28 is
Sit on 2.

As described above, the intake side drive circuit 30a alternately applies the exciting current to the first electromagnetic coil 308 and the second electromagnetic coil 309 at a predetermined timing, whereby the armature 311 is displaced to the valve closing side. The reciprocating operation is performed between the end and the valve-opening-side displacement end, whereby the valve shaft 28b is driven to reciprocate and the valve body 28a opens and closes at the same time.
Therefore, the intake side drive circuit 30a is connected to the first electromagnetic coil 3
The opening and closing timing of the intake valve 28 can be arbitrarily controlled by changing the application timing of the exciting current to the second electromagnetic coil 08 and the second electromagnetic coil 309.

The intake side electromagnetic drive mechanism 30 has a valve lift sensor 3 for detecting displacement of the intake valve 28.
17 are attached. This valve lift sensor 3
Reference numeral 17 denotes a disk-shaped target 317a attached to the upper surface of the applicator 312, and an adjustment bolt 31
3 and a gap sensor 317b attached to a portion facing the above-mentioned retainer 312.

In the valve lift sensor 317 thus configured, the target 317a is displaced integrally with the armature 311 of the intake-side electromagnetic drive mechanism 30, and the gap sensor 317b is replaced by the gap sensor 317b.
An electrical signal corresponding to the distance between the target and the target 317a is output.

At this time, the output signal value of the gap sensor 317b when the armature 311 is in a neutral state is stored in advance, and the deviation between the output signal value and the current output signal value of the gap sensor 317b is calculated. Thereby, the displacement of the armature 311 and the intake valve 28 can be specified.

Returning to FIGS. 1 and 2, an intake branch pipe 33 composed of four branch pipes is connected to the cylinder head 1a of the internal combustion engine 1. Each branch pipe of the intake branch pipe 33 is connected to each cylinder. 21 and an intake port 26.

In the cylinder head 1a, a fuel injection valve 32 is mounted in the vicinity of a connection portion with the intake branch pipe 33 so that its injection hole faces the intake port 26.

The intake branch pipe 33 is connected to a surge tank 34 for suppressing the pulsation of intake air. An intake pipe 35 is connected to the surge tank 34.
Is connected to an air cleaner box 36 for removing dust and dirt from the intake air.

An air flow meter 44 for outputting an electric signal corresponding to the mass of air flowing through the intake pipe 35 (mass of intake air) is attached to the intake pipe 35.
A throttle valve 39 for adjusting the flow rate of intake air flowing through the intake pipe 35 is provided at a position downstream of the air flow meter 44 in the intake pipe 35.

The throttle valve 39 is provided with a throttle actuator 40 for driving the opening and closing of the throttle valve 39 in accordance with the magnitude of the applied electric power.
And a throttle position sensor 41 for outputting an electric signal corresponding to the opening of the throttle valve 39.

The throttle valve 39 is rotatable independently of the throttle valve 39 and the accelerator pedal 4
An accelerator lever (not shown) that rotates in conjunction with 2 is attached to the accelerator lever, and an accelerator position sensor 43 that outputs an electric signal corresponding to the amount of rotation of the accelerator lever is attached to the accelerator lever.

On the other hand, the cylinder head 1 of the internal combustion engine 1
An exhaust branch pipe 45 formed so that four branch pipes merge into one collecting pipe immediately downstream of the internal combustion engine 1 is connected to a, and each branch pipe of the exhaust branch pipe 45 is connected to each cylinder 21. The exhaust port 27 communicates with the exhaust port 27.

The exhaust branch pipe 45 is connected to an exhaust pipe 47 via an exhaust purification catalyst 46, and the exhaust pipe 47 is connected downstream to a muffler (not shown). The exhaust branch pipe 4
5 is provided with an air-fuel ratio sensor 48 that outputs an electric signal corresponding to the air-fuel ratio of the exhaust flowing in the exhaust branch pipe 45, in other words, the exhaust flowing into the exhaust purification catalyst 46.

Here, the exhaust gas purifying catalyst 46 may be, for example, a hydrocarbon contained in the exhaust gas when the air-fuel ratio of the exhaust gas flowing into the exhaust gas purifying catalyst 46 is a predetermined air-fuel ratio near the stoichiometric air-fuel ratio. (HC), carbon monoxide (CO), nitrogen oxides (NOx), a three-way catalyst, and nitrogen contained in the exhaust when the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst 46 is a lean air-fuel ratio. When the air-fuel ratio of the exhaust gas flowing into the exhaust gas purifying catalyst 46 is a stoichiometric air-fuel ratio or a rich air-fuel ratio while the oxide (NOx) is being stored, the stored nitrogen oxides (NOx) are released and reduced and purified. When the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst 46 is in an oxygen excess state and a predetermined reducing agent is present, nitrogen oxides (NOx) in the exhaust gas are reduced.
It is a selective reduction type NOx catalyst to be purified, or a catalyst obtained by appropriately combining the various catalysts described above.

The internal combustion engine 1 configured as described above is provided with an electronic control unit (ECU) 20 for controlling the operating state of the internal combustion engine 1.

The ECU 20 includes a throttle position sensor 41, an accelerator position sensor 43, an air flow meter 44, an air-fuel ratio sensor 48, a crank position sensor 51, a water temperature sensor 52, and a valve lift sensor 3.
Various sensors such as 17 are connected via electric wiring, and output signals of each sensor are input to the ECU 20.

The ECU 20 includes an igniter 25a,
The intake-side drive circuit 30a, the exhaust-side drive circuit 31a, the fuel injection valve 32, the throttle actuator 40, and the like are connected via electric wiring, and the ECU 20 sets the igniter 25
a, the intake side drive circuit 30a, the exhaust side drive circuit 31a, the fuel injection valve 32, or the throttle actuator 40
Can be controlled.

Here, as shown in FIG. 4, the ECU 20 connects the CPs connected to each other by a bidirectional bus 400.
It has a U 401, a ROM 402, a RAM 403, a backup RAM 404, an input port 405 and an output port 406, and has an A / D converter (A / D) 407 connected to the input port 405.

The A / D 407 includes a throttle position sensor 41, an accelerator position sensor 43, an air flow meter 44, an air-fuel ratio sensor 48, and a water temperature sensor 5.
2. It is connected to a sensor that outputs a signal in the form of an analog signal, such as a valve lift sensor 317, via electric wiring. The A / D 407 converts the output signal of each sensor from an analog signal format to a digital signal format, and then transmits the converted signal to the input port 405.

The input port 405 outputs a signal in the form of an analog signal, such as the above-described throttle position sensor 41, accelerator position sensor 43, air flow meter 44, air-fuel ratio sensor 48, water temperature sensor 52, valve lift sensor 317, and the like. Sensor and A / D40
7 and is connected to a sensor that outputs a signal in digital signal format, such as a crank position sensor 51.

The input port 405 inputs the output signals of various sensors directly or through the A / D 407, and outputs those output signals through the bidirectional bus 400 to the CPU 401.
Or to the RAM 403.

The output port 406 is connected to the igniter 25
a, the intake-side drive circuit 30a, the exhaust-side drive circuit 31a, the fuel injection valve 32, the throttle actuator 40, and the like are connected via electric wiring. The output port 406
Receives a control signal output from the CPU 401 via the bidirectional bus 400 and transmits the control signal to the igniter 2.
5a, an intake side drive circuit 30a, an exhaust side drive circuit 31a,
Fuel injection valve 32 or throttle actuator 40
Send to

The ROM 402 includes a fuel injection amount control routine for determining the fuel injection amount, a fuel injection timing control routine for determining the fuel injection timing, and an intake valve opening / closing timing for determining the opening / closing timing of the intake valve 28. A control routine, an exhaust valve opening / closing timing control routine for determining the opening / closing timing of the exhaust valve 29, an intake side exciting current control routine for determining an exciting current amount to be applied to the intake side electromagnetic drive mechanism 30, and an exhaust side electromagnetic drive Exhaust-side excitation current amount control routine for determining the amount of excitation current to be applied to the mechanism 31; ignition timing control routine for determining the ignition timing of the spark plug 25 of each cylinder 21;
A secondary air supply control routine for supplying secondary air to the exhaust gas purification catalyst 46 is stored in addition to an application program such as a throttle opening control routine for determining the opening of No. 9.

The ROM 402 stores various control maps in addition to the application programs described above. The control map includes, for example, a fuel injection amount control map indicating a relationship between the operating state of the internal combustion engine 1 and the fuel injection amount, a fuel injection timing control map indicating a relationship between the operating state of the internal combustion engine 1 and the fuel injection timing, An intake valve opening / closing timing control map showing the relationship between the operating state of the internal combustion engine 1 and the opening / closing timing of the intake valve 28, the operating state of the internal combustion engine 1 and the exhaust valve 2
Exhaust valve opening / closing timing control map showing the relationship between the opening / closing timing of FIG. 9 and the intake side exciting current amount control map showing the relationship between the operating state of the internal combustion engine 1 and the amount of exciting current to be applied to the intake side electromagnetic drive mechanism 30 An exhaust-side exciting current control map showing the relationship between the operating state of the engine 1 and the amount of exciting current to be applied to the exhaust-side electromagnetic drive mechanism 31, and the relationship between the operating state of the internal combustion engine 1 and the ignition timing of each spark plug 25. And a throttle opening control map indicating the relationship between the operating state of the internal combustion engine 1 and the opening of the throttle valve 39.

The RAM 403 stores an output signal of each sensor, a calculation result of the CPU 401, and the like. The calculation result is, for example, an engine speed calculated based on an output signal of the crank position sensor 51. The RAM
Various data stored in 403 is updated to the latest data every time the crank position sensor 51 outputs a signal.

The backup RAM 404 is a non-volatile memory that retains data even after the operation of the internal combustion engine 1 is stopped, and stores learning values related to various controls, information for specifying a location where an abnormality has occurred, and the like.

The CPU 401 operates in accordance with the application program stored in the ROM 402, and includes, in addition to well-known controls such as fuel injection control, ignition control, intake valve opening / closing control, exhaust valve opening / closing control, and throttle control, the gist of the present invention. Is executed.

Hereinafter, the secondary air supply control according to the present embodiment will be described.

The exhaust purification catalyst 46 is
Is activated when the bed temperature of the exhaust gas is equal to or higher than a predetermined temperature, it becomes possible to purify the harmful gas components in the exhaust gas. When it is lower than the above value, it becomes inactive, and it is not possible to sufficiently purify harmful gas components in exhaust gas.

When the internal combustion engine 1 is cold started, the internal combustion engine 1 is operated at a rich air-fuel ratio in order to quickly warm up the internal combustion engine 1 and various engine-related elements associated with the internal combustion engine 1. That is, a so-called warm-up operation is performed. Therefore, during a warm-up operation after the internal combustion engine 1 is cold started, the air-fuel ratio of the exhaust gas of the internal combustion engine 1 also becomes a rich air-fuel ratio, and the exhaust gas contains a relatively large amount of unburned fuel components. .

Therefore, during the warm-up operation after the internal combustion engine 1 is cold started, secondary air is supplied to the exhaust gas purification catalyst 46 to oxidize unburned fuel components in the exhaust gas purification catalyst 46, and There is known a technique for improving exhaust emission by purifying a fuel component and raising the temperature of an exhaust purification catalyst 46 by reaction heat generated when an unburned fuel component is oxidized.

As a method of supplying the secondary air to the exhaust purification catalyst 46, an air pump is attached to an exhaust passage upstream of the exhaust purification catalyst 46, and secondary air is supplied from the air pump into the exhaust gas upstream of the exhaust purification catalyst 46. There is a method, a method of stopping fuel injection to some of the cylinders 21 of the internal combustion engine 1, and discharging the intake air from the cylinders 21 as they are.

However, when an air pump is attached to the exhaust system of the internal combustion engine 1, the structure of the exhaust system becomes complicated, causing problems such as deterioration in mountability on a vehicle. Further, when fuel injection to some of the cylinders 21 of the internal combustion engine 1 is stopped and secondary air is supplied to the exhaust purification catalyst 46,
Exhaust gas purification catalyst 4 without newly adding an air pump, etc.
6, it is possible to supply the secondary air to the internal combustion engine 6, but since the degree of freedom in controlling the torque of the internal combustion engine 1, the amount of the secondary air, and the like is low,
In some cases, torque fluctuation of the internal combustion engine 1, lack of secondary air, and the like may be induced.

Therefore, in the secondary air supply control according to the present embodiment, when supplying the secondary air to the exhaust purification catalyst 46, the CPU 401 stops the fuel injection to some of the cylinders 21 of the internal combustion engine 1. At the same time as supplying the secondary air to the exhaust purification catalyst 46, the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 are appropriately controlled.

More specifically, in the secondary air supply control, the CPU 401 first stops the supply of the drive current to the fuel injection valve 32 and the spark plug 25 of some of the cylinders 21 of the internal combustion engine 1 and Is stopped (hereinafter, the cylinder whose combustion is stopped is referred to as a stopped cylinder).

At this time, the CPU 401 determines whether the internal combustion engine 1
At least one of the cylinders 21 may be a deactivated cylinder, but it is preferable to deactivate the combustion of the two cylinders 21 so that the combustion occurrence intervals of the internal combustion engine 1 are equal. For example, the ignition order of the internal combustion engine 1 is the first cylinder 2
When the cylinder number is 1 → 3rd cylinder 21 → 4th cylinder 21 → 2nd cylinder 21, the CPU 401 sets the 1st cylinder 21 and the 4th cylinder 2
1 or the operation of the second cylinder 21 and the third cylinder 21 is stopped, and the crankshaft 23
Combustion is caused to occur every 60 °.

Subsequently, the CPU 401 increases the amount of secondary air to be discharged from the idle cylinder 21, for example, when the number of idle cylinders 21 is smaller than the number of active cylinders 21, When the load on the cylinder is high and the amount of unburned fuel component discharged from the working cylinder 21 is large, the intake side drive circuit 30a and the exhaust side drive circuit 31a of the inactive cylinder 21 are reduced in order to reduce the number of strokes in the inactive cylinder 21. Control.

More specifically, the CPU 401 determines that the idle cylinder 2
In order to change the opening / closing timing of the intake / exhaust valves 28 and 29 of 1 from an opening / closing timing corresponding to a 4-stroke cycle to an opening / closing timing corresponding to a 2-stroke cycle,
It controls the intake side drive circuit 30a and the exhaust side drive circuit 31a.

Here, in the cylinder 21 in which the intake / exhaust valves 28 and 29 operate according to the opening / closing timing corresponding to the four-stroke cycle, the crankshaft 23 moves 720 °.
Intake and exhaust are performed once during the rotation (two rotations). On the other hand, in the cylinder 21 in which the intake and exhaust valves 28 and 29 operate according to the opening and closing timing corresponding to the two-stroke cycle, the crankshaft 23
During one rotation (one rotation), intake and exhaust are performed once.

Accordingly, the intake and exhaust valves 28, 2
9 is changed from the opening / closing timing corresponding to the four-stroke cycle to the opening / closing timing corresponding to the two-stroke cycle, the crankshaft 2
The amount of exhaust (in this case, the amount of secondary air) exhausted from the idle cylinder 21 per one rotation of the cylinder 3 increases.
On the other hand, if combustion is simply stopped in some of the cylinders 21 of the internal combustion engine 1, the torque of the internal combustion engine 1 will be reduced.
1) to prevent a decrease in the torque of the internal combustion engine 1.

The CPU 401 calculates the required torque for the internal combustion engine 1 based on the output signal (accelerator opening) of the accelerator position sensor 43 and the engine speed. Next, the CPU 401 determines the target intake air amount and the target fuel injection amount of the working cylinder 21 so that the torque of the internal combustion engine 1 matches the target torque.

The CPU 401 determines the target opening / closing timing of the intake valve 28 of the working cylinder 21 and the target opening of the throttle valve 39 based on the target intake air amount.

Further, the CPU 401 determines the opening / closing timing of the exhaust valve 29 in order to increase the rate at which the heat energy generated when the air-fuel mixture burns in the working cylinder 21 is transmitted to the crankshaft 23.

For example, if the opening timing of the exhaust valve 29 of the working cylinder 21 is excessively advanced before the bottom dead center of the expansion stroke (bottom dead center of the exhaust stroke), the heat energy generated by the combustion of the air-fuel mixture will be lost. If a part of the exhaust gas is discharged without being transmitted to the crankshaft 23 and the valve opening start timing of the exhaust valve 29 is excessively retarded after the bottom dead center of the expansion stroke, the burned The gas is compressed by the piston 22, and the compression work causes loss of kinetic energy of the crankshaft 23, so-called pump loss occurs. Therefore, the opening timing of the exhaust valve 29 of the working cylinder 21 is preferably near the bottom dead center of the expansion stroke.

On the other hand, if the closing timing of the exhaust valve 29 of the working cylinder 21 is excessively advanced before the top dead center of the exhaust stroke (top dead center of the intake stroke), the remaining valve in the working cylinder 21 is left. A pump loss occurs in which the piston 22 compresses the fuel gas,
Conversely, if the closing timing of the exhaust valve 29 is excessively retarded after the top dead center of the exhaust stroke, the valve overlap amount of the intake and exhaust valves 28 and 29 excessively increases, and the intake air blows into the exhaust system. There is a possibility that it will end up. Therefore, the closing timing of the exhaust valve 29 is preferably near the top dead center of the exhaust stroke.

However, when high-temperature exhaust is discharged from the working cylinder 21 in order to promote the temperature rise of the exhaust purification catalyst 46, the valve opening timing of the exhaust valve 29 of the working cylinder 21 is advanced ahead of the bottom dead center of the exhaust stroke. In addition, the heat energy lost thereby may be compensated for by increasing the target intake air amount and the target fuel injection amount.

As described above, when the secondary air is supplied to the exhaust purification catalyst 46, the CPU 401 controls the intake side drive circuit 30a and the exhaust side drive circuit 31a so that the torque and the secondary air amount of the internal combustion engine 1 are reduced. In addition to being able to control arbitrarily, it is also possible to arbitrarily control the temperature and the like of the exhaust gas discharged from the working cylinder 21, so that the degree of freedom in the control related to the supply of the secondary air is increased.

Next, the secondary air supply control according to the present embodiment will be specifically described with reference to FIG.

FIG. 5 is a flowchart showing a secondary air supply control routine in this embodiment. The secondary air supply control routine is a routine stored in the ROM 402 in advance, and is a routine executed by the CPU 401 triggered by generation of a secondary air supply request. In the secondary air supply control routine, the CPU 401 first executes S50.
In step 1, a secondary air request flag storage area preset in a predetermined area of the RAM 403 is accessed, and it is determined whether or not "1" is stored in the secondary air request flag storage area.

The secondary air request flag storage area is set to "1" when it becomes necessary to supply secondary air to the exhaust purification catalyst 46, so that it is not necessary to supply secondary air to the exhaust purification catalyst 46. (For example, the exhaust purification catalyst 4
6 is activated) (when 6 is activated).

The time at which the secondary air needs to be supplied to the exhaust purification catalyst 46 is, for example, when the internal combustion engine 1 is in a warm-up operation state after a cold start, and It is preferred that at least a part is active. This is because when the secondary air is supplied to the exhaust purification catalyst while the entire exhaust purification catalyst 46 is in an inactive state, not only the unburned fuel components are not oxidized in the exhaust purification catalyst 46 but also the low-temperature secondary This is because the exhaust gas purification catalyst 46 may be cooled by the air.

As a method for determining whether at least a part of the exhaust purification catalyst 46 is activated, a temperature sensor is attached to the exhaust purification catalyst 46 and the output signal value of the temperature sensor is set to a predetermined temperature (for example, 150 ° C. to 150 ° C.). 250 ° C.) or more, a method of determining that at least a part of the exhaust gas purification catalyst 46 is active, an output signal value (cooling water temperature) of the water temperature sensor 52 at the time of engine start, and intake air from the engine start. A method of estimating from the integrated value of the amount, a method of estimating from the cooling water temperature at the time of starting the engine and the operating time since the start of the engine, the cooling water temperature at the time of starting the engine, the amount of intake air from the start of the engine, and the fuel injection A method of estimating from the integrated value of the amount and the like can be exemplified.

Since the activation temperature of the exhaust purification catalyst 46 may change depending on the degree of deterioration of the exhaust purification catalyst 46, it is determined whether at least a part of the exhaust purification catalyst 46 is active. At this time, the degree of deterioration of the exhaust purification catalyst 46 may be considered.

If it is determined in step S501 that "0" is not stored in the secondary air request flag storage area, the CPU 401 ends the execution of this routine.

On the other hand, if it is determined in step S501 that “1” is stored in the secondary air request flag storage area, the CPU 401 proceeds to step S502 and executes a secondary air supply process for the exhaust purification catalyst 46. I do.

In the secondary air supply processing, the CPU 401
First, a part of the four cylinders 21 of the internal combustion engine 1
The application of the drive current to the first fuel injection valve 32 and the ignition plug 25 is stopped, and some of the above-described cylinders 21 are set to the idle cylinders.

At this time, the CPU 401 adjusts the opening / closing timing of the intake / exhaust valves 28 and 29 of the deactivated cylinder 21 by four if necessary.
2 from opening / closing timing corresponding to stroke cycle
In order to change the opening / closing timing corresponding to the stroke cycle, the intake side drive circuit 30a and the exhaust side drive circuit 31
is controlled to increase the amount of secondary air discharged from the idle cylinder 21.

Subsequently, the CPU 401 calculates the required torque for the internal combustion engine 1 based on the output signal (accelerator opening) of the accelerator position sensor 43 and the engine speed. The CPU 401 determines the target intake air amount and the target fuel injection amount of the working cylinder 21 so that the torque of the internal combustion engine 1 matches the target torque. And the CPU 401
Determines the target opening / closing timing of the intake valve 28 of the working cylinder 21 and the target opening of the throttle valve 39 based on the target intake air amount.

Further, the CPU 401 determines the opening / closing timing of the exhaust valve 29 in order to increase the rate at which the thermal energy generated when the air-fuel mixture burns in the working cylinder 21 is transmitted to the crankshaft 23.

Further, the CPU 401 increases the opening of the throttle valve 39 so as to increase the intake air amount of the idle cylinder 21 and the working cylinder 21 (for example, the throttle valve 39).
Fully open).

After starting the execution of the secondary air supply process as described above, the CPU 401 proceeds to S503, and determines whether or not the entire exhaust purification catalyst 46 has been activated. As the determination method, a method of attaching a temperature sensor to the exhaust purification catalyst 46 to determine whether or not the output signal value of the temperature sensor is equal to or higher than a predetermined activation temperature, and the execution time of the secondary air supply process is equal to or longer than a predetermined time A method of estimating that the entire exhaust purification catalyst 46 has been activated when the above condition is satisfied can be exemplified.

If it is determined in step S503 that the entire exhaust purification catalyst 46 has not been activated, the CPU 4
In step 01, the process returns to step S502, and the execution of the secondary air supply process is continued.

On the other hand, if it is determined in S503 that the entire exhaust purification catalyst 46 has been activated, the CPU 401
Proceeds to S504, ends the execution of the secondary air supply process, and returns the internal combustion engine 1 to the normal operation state. That is, the CPU 401 sets the opening / closing timing of the intake / exhaust valves 28 and 29 for the deactivated cylinder 21 to the normal four strokes.
The operation timing is returned to the opening / closing timing corresponding to the cycle, and the application of the drive current to the fuel injection valve 32 and the ignition plug 25 is resumed. For the working cylinder 21, the fuel injection amount is returned to the normal fuel injection amount, and the intake / exhaust valve 28 The opening / closing timing of the throttle valve 29 is returned to the normal opening / closing timing, and the throttle actuator 41 is controlled to return the opening of the throttle valve 39 to the normal target throttle opening.

When the processing in S504 is completed, C
The PU 401 proceeds to S505 and resets the value of the secondary air request flag storage area of the RAM 403 to “0”.
The execution of this routine ends.

As described above, when the CPU 401 executes the secondary air supply control routine, the valve mechanism control means according to the present invention is realized.

Therefore, according to the control apparatus for the electromagnetically driven valve according to the present embodiment, when the secondary air is supplied to the exhaust gas purification catalyst 46, the intake side drive circuit 30a and the exhaust side drive circuit 31
By controlling a, the torque and the secondary air amount of the internal combustion engine 1 can be arbitrarily controlled, and the temperature of exhaust gas discharged from the working cylinder 21 can be arbitrarily controlled. Therefore, the degree of freedom of the control related to the supply of the secondary air is increased. As a result, some cylinders 21 of the internal combustion engine 1
When the secondary air is supplied to the exhaust purification catalyst 46 by reducing the fuel injection amount (or stopping the fuel injection), the torque fluctuation of the internal combustion engine 1 is easily suppressed, and the supply amount of the secondary air is desired. It is also easy to set the amount to.

In the above-described secondary air supply control,
Even when it is not necessary to operate the idle cylinder 21 in a two-stroke cycle, the idle cylinder 21 is operated in a two-stroke cycle to increase the amount of secondary air, and the mixture supplied to the operating cylinder 21 is increased. By lowering the air-fuel ratio of the exhaust purifying catalyst 46, the amount of unburned fuel component oxidized by the exhaust purifying catalyst 46 may be increased, so that the temperature rise of the exhaust purifying catalyst 46 may be further promoted.

Further, in the present embodiment, the electromagnetically driven valve mechanism capable of arbitrarily changing the opening / closing timing of the intake valve 28 and the exhaust valve 29 has been described as an example, but the lift amount can be changed in addition to the opening / closing timing. An electromagnetically driven valve mechanism may be used. In that case, the lift amount of the intake valve 28 may be increased when increasing the intake air amount of each cylinder 21.

[0120]

According to the present invention, when the secondary air is supplied to the exhaust purification catalyst disposed in the exhaust passage of the internal combustion engine, the secondary air supply is controlled by controlling the electromagnetically driven valve mechanism. Since it becomes possible to increase the degree of freedom of control according to
For example, it becomes easy to arbitrarily control the torque of the internal combustion engine, the supply amount of the secondary air, and the like.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of an internal combustion engine according to the present invention.

FIG. 2 is a sectional view showing a schematic configuration of an internal combustion engine according to the present invention.

FIG. 3 is a diagram showing an internal configuration of an intake-side electromagnetic drive mechanism.

FIG. 4 is a block diagram showing an internal configuration of an ECU.

FIG. 5 is a flowchart showing a secondary air supply control routine.

[Explanation of symbols]

 1 Internal combustion engine 20 ECU 25 Spark plug 25a Igniter 26 Intake port 27 Exhaust port 28 Intake valve 29 ··· Exhaust valve 30 ··· Intake side electromagnetic drive mechanism 30a ··· Intake side drive circuit 31 ···· Exhaust side electromagnetic drive mechanism 31a ··· Exhaust side drive circuit 32 ··· Fuel injector 401 · ..CPU 402 ... ROM

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F02D 17/02 F02D 17/02 MPR 41/04 320 41/04 320 330 330 330J 41/36 41/36 B 43/00 301 43/00 301H 301T 301Z F term (reference) 3G018 AA06 AB09 AB17 CA16 DA34 3G084 AA03 AA04 BA05 BA09 BA13 BA15 BA17 BA23 BA24 CA01 CA02 CA03 CA06 DA10 DA27 EA11 EB01 FA07 FA10 FA20 FA26 FA29 FA33 FA38 FA39 3 AA17 AA23 AA28 AB03 AB05 AB06 BA03 BA04 BA14 BA15 BA19 BA32 CA21 CB02 CB03 CB05 CB06 CB07 CB08 DA01 DA02 DA08 DA10 DB10 EA00 EA01 EA05 EA07 EA16 EA31 EA34 FA02 FA04 FA05 FA12 FA13 A13 A01 FC3 BA09 BB01 CA03 CB02 CB05 DA01 DA02 DA07 DA12 DC03 DC16 DG02 DG08 DG09 EA01 EA02 EC10 FA18 GA02 HA01Z HA06X HA06Z HA 13X HA13Z HB01X HD02Z HD05Z HE03Z HE06X HE08Z HF08Z 3G301 HA01 HA07 HA19 JA25 JA26 JB09 KA02 KA05 KA07 KA08 KA16 KA26 KA27 LA03 LA07 LB02 MA01 MA11 MA18 MA24 MA26 NA06 NA07 NA08 PE04 PE03 PE01 PE03 PE01 PE03 PE03 PE08B PE08Z PE10B PE10Z PF03B PF03Z

Claims (3)

[Claims] An exhaust purification catalyst provided in an exhaust passage of an internal combustion engine; an electromagnetically driven valve mechanism for opening and closing at least one of an intake valve and an exhaust valve of the internal combustion engine using electromagnetic force; A control device for an electromagnetically driven valve, comprising: valve operating mechanism control means for controlling the electromagnetically driven valve operating mechanism when supplying secondary air to the exhaust purification catalyst. 2. The valve operating mechanism control means further comprising secondary air supply means for reducing a fuel injection amount of a predetermined cylinder among a plurality of cylinders provided in the internal combustion engine and supplying secondary air to the exhaust purification catalyst. 2. The electromagnetically driven valve control device according to claim 1, wherein the controller controls an electromagnetically driven valve operating mechanism of a cylinder other than the predetermined cylinder such that a torque of the internal combustion engine matches a target torque. 3. The valve operating mechanism control means further comprising: secondary air supply means for reducing a fuel injection amount of a predetermined cylinder among a plurality of cylinders provided in the internal combustion engine to supply secondary air to the exhaust purification catalyst. The control apparatus for an electromagnetically driven valve according to claim 1, wherein the controller controls the electromagnetically driven valve operating mechanism of the predetermined cylinder to reduce the number of strokes of the predetermined cylinder.