JP2001182564A - Internal combustion engine comprising solenoid driving valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unnecessary increase in electric power consumption and working failure of intake and exhaust valves by providing technology allowing to operate a solenoid driving type valve system with a minimum excitation electric power required as a driving electric power to be applied to the solenoid driving type valve system in an internal combustion engine provided with the solenoid driving type valve system driven by using electromagnetic force to open and close the intake valve and/or the exhaust valve. SOLUTION: This internal combustion engine comprising the solenoid driving valve is provided with an electromagnetic driving mechanism for driving the intake valve and the exhaust valve of the internal combustion engine to open and close using the electromagnetic force generated when the excitation electric power is applied, a rotation fluctuation detecting means for detecting rotation fluctuation of the internal combustion engine, and an excitation electric power adjusting means for adjusting magnitude of the excitation electric power to be applied to the electromagnetic driving mechanism according to a value detected by the rotation fluctuation detecting means. The electromagnetic driving mechanism is operated by the excitation electric power corresponding to combustion pressure generated in a cylinder in an expansion stroke and an exhaust stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating mechanism for an internal combustion engine mounted on an automobile or the like, and more particularly to an electromagnetically driven valve operating mechanism for opening and closing an intake valve and an exhaust valve by using an electromagnetic force.

[0002]

2. Description of the Related Art In recent years, in internal combustion engines mounted on automobiles and the like, mechanical loss caused by opening and closing of intake and exhaust valves has been prevented.
For the purpose of preventing pumping loss of intake air, improving net thermal efficiency, and the like, the development of an electromagnetically driven valve mechanism that opens and closes an intake valve and an exhaust valve using electromagnetic force has been promoted.

[0003] Such an electromagnetically driven valve mechanism includes:
For example, an armature made of a magnetic material and moving forward and backward in conjunction with an intake / exhaust valve, a valve-closing electromagnet that attracts the armature in a valve closing direction when an exciting current is applied, and an armature when an exciting current is applied A valve-opening electromagnet that attracts the armature in the valve-opening direction, a valve-closing-side return spring that urges the armature in the valve-closing direction, and a valve-opening-side return spring that urges the armature in the valve-opening direction. Are known.

According to such an electromagnetically driven valve train,
Since there is no need to open and close the intake and exhaust valves using the rotational force of the engine output shaft (crankshaft) as in a conventional valve operating mechanism, loss of engine output due to driving of the intake and exhaust valves is prevented. .

Further, according to the electromagnetic drive device described above, it is not necessary to open and close the intake and exhaust valves in conjunction with the rotation of the engine output shaft unlike the conventional valve operating mechanism. The intake and exhaust valves can be opened and closed at any time by changing the application timing of the excitation current to the valve electromagnet, so that the intake air amount of each cylinder can be controlled without using an intake throttle valve (throttle valve). It is possible to do. As a result, pumping loss of intake air caused by the throttle valve is suppressed.

On the other hand, in the electromagnetically driven valve mechanism as described above, it is also important to reduce the amount of electric power required for operating the electromagnetically driven valve mechanism. In response to such a demand, an electromagnetically driven valve control device for an internal combustion engine as described in Japanese Patent Application Laid-Open No. 9-21304 has been proposed.

[0007] The electromagnetically driven valve control device described in the above-mentioned publication discloses an engine output in an internal combustion engine provided with an electromagnetically driven valve operating mechanism for opening and closing an intake valve or an exhaust valve of the internal combustion engine by using an electromagnetic force. The pressure in each cylinder is estimated using the rotational position of the shaft, the rotational speed of the engine output shaft, and the engine load as parameters, and the drive power to be applied to the electromagnetically driven valve mechanism based on the estimated cylinder pressure is estimated. By changing the magnitude, an attempt is made to prevent an increase in power consumption caused by applying excessive drive power to the electromagnetically driven valve train.

[0008]

In a four-cycle internal combustion engine, the pressure in a cylinder during an expansion stroke or an exhaust stroke changes according to the magnitude of the combustion pressure generated by the combustion of the air-fuel mixture.

However, the combustion of the air-fuel mixture varies depending on the ambient temperature in the cylinder, the state of the air-fuel mixture, and the like, even if the operating state of the internal combustion engine is the same. When the pressure in the cylinder during the expansion stroke or the exhaust stroke is estimated using the rotational position of the engine output shaft, the engine speed, and the engine load as parameters as in the device, the error between the estimated value and the actual cylinder pressure is large. May be.

When the error between the estimated value of the in-cylinder pressure in the expansion stroke or the exhaust stroke and the actual in-cylinder pressure becomes large, the driving power having a magnitude corresponding to the actual pressure in the cylinder is electromagnetically driven. It becomes difficult to apply the voltage to the valve operating mechanism, which may lead to an increase in power consumption and an operation failure of the electromagnetically driven valve operating mechanism.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is directed to an internal combustion engine provided with an electromagnetically driven valve operating mechanism that opens and closes an intake valve and / or an exhaust valve using electromagnetic force. A technique that enables the drive power to be applied to the electromagnetically driven valve mechanism to have a magnitude corresponding to the pressure in each cylinder, in particular, a drive power having a magnitude corresponding to the pressure in the cylinder in an expansion stroke or an exhaust stroke. By providing technology that can be applied to electromagnetically driven valve mechanisms,
An object of the present invention is to prevent unnecessary increase in power consumption associated with the operation of an electromagnetically driven valve mechanism and prevent malfunction of the electromagnetically driven valve mechanism.

[0012]

The present invention employs the following means in order to solve the above-mentioned problems.
That is, an internal combustion engine having an electromagnetically driven valve according to the present invention includes an electromagnetically driven mechanism that opens and closes an intake valve and an exhaust valve of an internal combustion engine using an electromagnetic force generated when excitation power is applied; Rotation fluctuation detection means for detecting rotation fluctuation of the engine, and excitation power adjustment means for adjusting the magnitude of excitation power to be applied to the electromagnetic drive mechanism in accordance with a detection value of the rotation fluctuation detection means. Features.

In the internal combustion engine having the electromagnetically driven valve configured as described above, the rotation fluctuation detecting means detects the rotation fluctuation of the internal combustion engine. The exciting power adjusting means adjusts the magnitude of the exciting power to be applied to the electromagnetic drive mechanism according to the magnitude of the rotation fluctuation detected by the rotation fluctuation detecting means.

In this case, the electromagnetic drive mechanism drives the opening and closing of the intake valve and the exhaust valve by the excitation power corresponding to the magnitude of the rotation fluctuation of the internal combustion engine. For example, in a four-cycle internal combustion engine, it is necessary to keep the intake valve and the exhaust valve in a fully closed state in a cylinder in an expansion stroke. However, in a cylinder in an expansion stroke, a high combustion pressure is generated due to combustion of an air-fuel mixture. However, since the combustion pressure acts to close the intake valve and the exhaust valve, the electromagnetic drive mechanism can maintain the intake valve and the exhaust valve in a closed state with relatively small excitation power.

In a four-cycle internal combustion engine, it is necessary to open the exhaust valve of the cylinder in the exhaust stroke while holding the intake valve in the fully closed state. Since the combustion pressure generated during the stroke remains, and the remaining pressure acts to close the intake valve and the exhaust valve, the electromagnetic drive mechanism holds the intake valve in the closed state with relatively small excitation power. On the other hand, it is necessary to open the exhaust valve with a relatively large exciting power.

Here, the magnitude of the combustion pressure generated when the air-fuel mixture is burned in the internal combustion engine is reflected in the engine speed fluctuation immediately after the air-fuel mixture is burned. That is, as the combustion pressure generated by combustion of the air-fuel mixture increases, the engine speed immediately after combustion of the air-fuel mixture increases, and the engine rotation fluctuation on the acceleration side increases.

Therefore, as in the case of an internal combustion engine having the electromagnetically driven valve according to the present invention, by adjusting the magnitude of the excitation power to be applied to the electromagnetically driven mechanism based on the magnitude of the engine rotation fluctuation, the necessary minimum It is possible to reliably open and close the intake valve and the exhaust valve by the excitation power of.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of an internal combustion engine having an electromagnetically driven valve according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine having an electromagnetically driven valve according to the present invention. The internal combustion engine 1 shown in FIG. 1 includes a plurality of cylinders 21 and each cylinder 21
This is a four-cycle gasoline engine equipped with a fuel injection valve 32 for directly injecting fuel into the inside.

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

A crankshaft 23 as an engine output shaft is rotatably supported on the cylinder block 1b.
The crankshaft 23 is connected to a piston 22 slidably mounted in each cylinder 21.

Above the piston 22, a piston 2
2 and a combustion chamber 24 surrounded by the wall surface of the cylinder head 1a. An ignition plug 25 is attached to the cylinder head 1a so as to face the combustion chamber 24.
An igniter 25 a for applying a drive current to the ignition plug 25 is connected to the ignition plug 25.

The cylinder head 1a is formed so that the open ends of the two intake ports 26 and the two exhaust ports 27 face the combustion chamber 24, and the injection holes thereof face the combustion chamber 24. A fuel injection valve 32 is attached.

Each open end of the intake port 26 is opened and closed by an intake valve 28 supported on the cylinder head 1a so as to be movable forward and backward.
It is opened and closed by an electromagnetic drive mechanism 30 (hereinafter, referred to as an intake-side electromagnetic drive mechanism 30) provided on the cylinder head 1a.

Each opening end of the exhaust port 27 is opened and closed by an exhaust valve 29 supported on the cylinder head 1a so as to be able to move forward and backward. These exhaust valves 29 are provided on the cylinder head 1a. It is opened and closed by a drive mechanism 31 (hereinafter, referred to as an exhaust-side electromagnetic drive mechanism 31).

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

As shown in FIG. 2, the intake-side electromagnetic drive mechanism 30 has a housing 300 made of a non-magnetic material and formed in a cylindrical shape.
It has. The housing 300 has a first soft magnetic material having an outer diameter substantially equal to the inner diameter of the housing 300.
The core 301 and the second core 302 are arranged in series with a predetermined gap.

A portion of the first core 301 facing the predetermined gap holds a first electromagnetic coil 303, and a portion of the second core 302 facing the first electromagnetic coil 303 is Second electromagnetic coil 304
Is gripped.

In the predetermined gap, the housing 300
Is provided with a plunger 305 made of a disk-shaped soft magnetic material having an outer diameter substantially equal to the inner diameter of the plunger. The plunger 305 is supported by a first spring 306 held in a hollow portion of the first core 301 and a second spring 307 held in a hollow portion of the second core 302 so as to be able to advance and retreat in the axial direction. I have.

The first spring 306 and the second spring 306
The urging force of the spring 307 causes the plunger 305 to move between the first core 301 and the second core in the predetermined gap.
It is set to be balanced when it is at an intermediate position with respect to the core 302.

On the other hand, the intake valve 28 has a valve body 28a which opens and closes the intake port 26 by seating or unseating on a valve seat 200 provided at the open end of the intake port 26 in the combustion chamber 24, and a tip portion thereof. And a cylindrical valve shaft 28b fixed to the valve body 28a.

The valve shaft 28b is connected to the cylinder head 1
a is supported by a cylindrical valve guide 201 provided at a. The base end of the valve shaft 28b extends into the housing 300 of the intake-side electromagnetic drive mechanism 30, and is fixed to the plunger 305 via the hollow portion of the second core 302.

The length of the valve shaft 28b in the axial direction is such that the plunger 305 has the first length in the predetermined gap.
When held at an intermediate position between the core 301 and the second core 302, that is, when the plunger 305 is in a neutral state, the valve body 28a is positioned between the fully open side displacement end and the fully closed side displacement end. It is set to be held at a position (hereinafter, referred to as a middle-open position).

In the intake-side electromagnetic drive mechanism 30 configured as described above, when the exciting current is not applied to the first electromagnetic coil 303 and the second electromagnetic coil 304, the plunger 305 is in a neutral state, and Accompanying valve 2
8a is held in the middle open position.

When an exciting current is applied to the first electromagnetic coil 303 of the intake-side electromagnetic drive mechanism 30, the first core 30
An electromagnetic force is generated between the first and first electromagnetic coils 303 and the plunger 305 in a direction to displace the plunger 305 toward the first core 301.

On the other hand, the second electromagnetic drive mechanism 30 of the intake side
When an exciting current is applied to the electromagnetic coil 304, the second core 302, the second electromagnetic coil 304, and the plunger 305
Between the plunger 305 and the second core 30.
An electromagnetic force is generated in the direction of displacing to the two sides.

Therefore, in the intake-side electromagnetic drive mechanism 30, the exciting current is alternately applied to the first electromagnetic coil 303 and the second electromagnetic coil 304, whereby the plunger 30 is driven.
5, the valve body 28a is driven to open and close. At this time, by changing the timing of applying the exciting current to the first electromagnetic coil 303 and the second electromagnetic coil 304 and the magnitude of the exciting current, the opening / closing timing of the intake valve 28 can be controlled.

Returning to FIG. 1, each intake port 26 of the internal combustion engine 1 is connected to the cylinder head 1a of the internal combustion engine 1.
Is connected to each branch pipe of the intake branch pipe 33 attached to the suction pipe. The intake branch pipe 33 is connected to a surge tank 34 for suppressing pulsation of intake air. An intake pipe 35 is connected to the surge tank 34. The intake pipe 35 is provided with an air cleaner box 3 for removing dust and dirt during intake.
6 is connected.

The intake pipe 35 is provided with an air flow meter 44 for outputting an electric signal corresponding to the mass of the air flowing through the intake pipe 35 (mass of the intake air).
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 comprising a stepper motor or the like for driving the opening and closing of the throttle valve 39 in accordance with the magnitude of the applied power.
A throttle position sensor 41 for outputting an electric signal corresponding to the opening of the throttle valve 39; and an accelerator position sensor mechanically connected to an accelerator pedal 42 for outputting an electric signal corresponding to the operation amount of the accelerator pedal 42. 43 are attached.

A vacuum sensor 50 for outputting an electric signal corresponding to the pressure of the surge tank 34 is attached to the surge tank 34. On the other hand, each exhaust port 27 of the internal combustion engine 1 communicates with each branch pipe of the exhaust branch pipe 45 attached to the cylinder head 1a. The exhaust branch pipe 45 is connected to the exhaust pipe 4 via an exhaust purification catalyst 46.
The exhaust pipe 47 is connected downstream to a muffler (not shown).

The exhaust branch pipe 45 has an air-fuel ratio of the exhaust gas flowing through the exhaust branch pipe 45, in other words, an exhaust purification catalyst 46.
An air-fuel ratio sensor 48 that outputs an electric signal corresponding to the air-fuel ratio of the exhaust gas flowing into the air-fuel ratio is attached.

The exhaust gas purifying catalyst 46 is, for example, hydrocarbon (HC) 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. Carbon oxide (CO), nitrogen oxide (NOx)
When the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst 46 is a lean air-fuel ratio, the three-way catalyst stores nitrogen oxides (NOx) contained in the exhaust gas, and the air-fuel ratio of the inflowing exhaust gas becomes stoichiometric. When the fuel ratio or the rich air-fuel ratio is attained, the occlusion-reduction type NOx catalyst that reduces and purifies while releasing the stored nitrogen oxides (NOx), and the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst 46 becomes an oxygen excess state When there is a predetermined reducing agent, 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 exhaust gas purifying catalyst 46 is provided with a catalyst temperature sensor 49 for outputting an electric signal corresponding to the bed temperature of the exhaust gas purifying catalyst 46. The internal combustion engine 1
Is a crank position sensor 51 including a timing rotor 51a attached to an end of the crankshaft 23, an electromagnetic pickup 51b attached to a cylinder block 1b near the timing rotor 51a, and a cooling unit formed inside the internal combustion engine 1. A water temperature sensor 52 attached to the cylinder block 1b for detecting the temperature of the cooling water flowing through the water channel 1c is provided.

The thus configured internal combustion engine 1 is provided with an electronic control unit (ECU) 20 for controlling the operation 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, and a catalyst temperature sensor 4.
9, various sensors such as a vacuum sensor 50, a crank position sensor 51, and a water temperature sensor 52 are connected via electric wiring, and output signals of the sensors are input to the ECU 20.

The ECU 20 includes an igniter 25a,
The intake-side electromagnetic drive mechanism 30, the exhaust-side electromagnetic drive mechanism 31, the fuel injection valve 32, and the like are connected via electric wiring.
The value 0 allows the igniter 25a, the intake-side electromagnetic drive mechanism 30, the exhaust-side electromagnetic drive mechanism 31, and the fuel injection valve 32 to be controlled using the output signal values of various sensors as parameters.

Here, as shown in FIG. 3, 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 input port 405 receives an output signal of a sensor such as the crank position sensor 51 which outputs a digital signal, and converts those output signals to C.
The data is transmitted to the PU 401 or the RAM 403.

The input port 405 outputs analog signal type signals such as a throttle position sensor 41, an accelerator position sensor 43, an air flow meter 44, an air-fuel ratio sensor 48, a catalyst temperature sensor 49, a vacuum sensor 50, and a water temperature sensor 52. Output signals of the sensors to be input through the A / D 407, and those output signals
The data is transmitted to the PU 401 and the RAM 403.

The output port 406 is connected to the CPU 40
1 is transmitted to the igniter 25a, the intake-side electromagnetic drive mechanism 30, the exhaust-side electromagnetic drive mechanism 31, and the fuel injection valve 32.

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 the opening of the intake valve for determining the opening timing of the intake valve 28. Valve timing control routine,
Exhaust valve opening timing control routine for determining the valve opening timing of the exhaust valve 29, ignition timing control routine for determining the ignition timing of the spark plug 25 of each cylinder 21, throttle valve 39
Excitation current control routine for determining the amount of excitation current to be applied to the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 in addition to an application program such as a throttle opening control routine for determining the opening of the vehicle. I remember.

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, an exhaust 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 exhaust valve 29, Internal combustion engine 1
Current amount control map showing the relationship between the operating state of the engine and the amount of exciting current to be applied to the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31; the operating state of the internal combustion engine 1 and each ignition plug 2
And a throttle opening control map showing the relationship between the operating state of the internal combustion engine 1 and the opening of the throttle valve 39, and the like.

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
The various data stored in 403 is rewritten to the latest data every time the crank position sensor 51 outputs a signal.

The backup RAM 45 is a non-volatile memory that retains data even after the operation of the internal combustion engine 1 is stopped, and stores learning values and the like for various controls. The CPU
401 operates in accordance with the application program stored in the ROM 402, and executes excitation current amount control which is the gist of the present invention, in addition to fuel injection control, intake valve opening / closing control, exhaust valve opening / closing control, ignition control, and the like.

Hereinafter, the excitation current amount control according to this embodiment will be described. In the four-cycle internal combustion engine 1, it is necessary to open the intake valve 28 and maintain the exhaust valve 29 in the fully closed state for the cylinder 21 in the intake stroke.

In the cylinder 21 in the intake stroke, the piston 2
2, a negative pressure is generated, and the negative pressure is generated by the intake valve 28.
Of the intake valve 2 is controlled by the intake side electromagnetic drive mechanism 30 with a relatively small amount of exciting current.
8 can be opened.

Incidentally, the degree of negative pressure of the negative pressure generated in the cylinder 21 during the intake stroke is such that the engine speed is low and the throttle valve 39
Becomes smaller as the opening of the throttle valve 39 increases, and decreases as the engine speed increases and the opening of the throttle valve 39 increases.

Therefore, in the present embodiment, the CPU 401
When an exciting current is applied to the intake-side electromagnetic drive mechanism 30 to open the intake valve 28 of the cylinder 21 in the intake stroke, the exciting current amount decreases as the engine speed decreases and the opening of the throttle valve 39 decreases. And the amount of exciting current is increased as the engine speed is increased and the opening of the throttle valve 39 is increased.

On the other hand, the exhaust valve 2 of the cylinder 21 in the intake stroke
In the case of 9, the exhaust valve 29 must be held in a fully closed state against the negative pressure generated by the lowering of the piston 22. Therefore, in the present embodiment, when applying an exciting current to the exhaust-side electromagnetic drive mechanism 31 to maintain the exhaust valve 29 of the cylinder 21 in the intake stroke in the fully closed state, the CPU 401 operates at a low engine speed and As the opening of the throttle valve 39 decreases, the amount of the exciting current increases, and as the engine speed increases and the opening of the throttle valve 39 increases, the amount of the exciting current decreases.

Next, in the four-stroke internal combustion engine 1, for the cylinder 21 in the compression stroke, the intake valve 28 and the exhaust valve 2
9 must be kept in the fully closed state. The internal pressure of the cylinder 21 during the compression stroke is increased by the rising operation of the piston 22, and the pressure acts to maintain the intake valve 28 and the exhaust valve 29 in the closed state.
The zero and exhaust side electromagnetic drive mechanism 31 can hold the intake valve 28 and the exhaust valve 29 in a closed state with a relatively small amount of exciting current.

The pressure of the cylinder 21 during the compression stroke decreases as the engine speed decreases and the opening of the throttle valve 39 decreases, and the engine speed increases and the throttle valve 3 increases.
9 increases as the opening degree increases.

Therefore, in the present embodiment, the CPU 401
Are the intake valve 28 and the exhaust valve 2 of the cylinder 21 in the compression stroke.
When an exciting current is applied to the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 in order to hold 9 in the fully closed state,
The amount of exciting current is increased as the engine speed decreases and the opening of the throttle valve 39 decreases, and the amount of exciting current decreases as the engine speed increases and the opening of the throttle valve 39 increases.

Next, in the four-cycle internal combustion engine 1, for the cylinder 21 in the expansion stroke, the intake valve 28 and the exhaust valve 2
9 must be kept in the fully closed state. In the cylinder 21 in the expansion stroke, although the piston 22 moves down, a high combustion pressure is generated by the combustion of the air-fuel mixture, and the combustion pressure acts to maintain the intake valve 28 and the exhaust valve 29 in the closed state. In addition, the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 can hold the intake valve 28 and the exhaust valve 29 in a closed state with a relatively small amount of exciting current.

The combustion pressure of the cylinder 21 during the expansion stroke can be estimated from the engine speed, the intake air amount, the fuel injection amount, and the like. However, the engine speed, the intake air amount, and the fuel injection amount can be estimated. Even if the conditions such as the amount are the same, cylinder 2
If the ambient temperature and the degree of atomization of the fuel in the fuel cell 1 are different, the combustion state of the air-fuel mixture may be different.

On the other hand, in the present embodiment, the excitation current amounts of the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 are determined using the engine rotation fluctuation having a strong correlation with the combustion pressure as a parameter. .

This is because when the combustion pressure in the cylinder 21 in the expansion stroke increases, the descending speed of the piston 22 increases, and the engine speed increases accordingly.
This is based on the knowledge that the engine rotation fluctuation on the acceleration side occurs.

The correlation between the combustion pressure and the engine speed fluctuation is considered to be particularly strong at the beginning of the expansion stroke of each cylinder 21, in other words, immediately after the combustion of the air-fuel mixture. It is assumed that the exciting currents of the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 are determined using the engine rotation fluctuation at the beginning of the expansion stroke as a parameter.

Then, the CPU 401 applies an exciting current to the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 in order to keep the intake valve 28 and the exhaust valve 29 of the cylinder 21 in the expansion stroke in a fully closed state. It is considered that as the engine rotation fluctuation on the acceleration side in the early stage of the expansion stroke of the cylinder 21 becomes smaller, the combustion pressure is regarded as lower, and the amount of the excitation current is increased, and the engine rotation fluctuation on the acceleration side in the initial stage of the expansion stroke of the cylinder 21 becomes larger. Assuming that the combustion pressure is high, the amount of exciting current is reduced.

Next, in the four-cycle internal combustion engine 1, for the cylinder 21 in the exhaust stroke, it is necessary to open the exhaust valve 29 while keeping the intake valve 28 fully closed. In the cylinder 21 in the exhaust stroke, the combustion pressure generated in the expansion stroke remains, and the piston 22 moves upward, so that the intake valve 28 and the exhaust valve 29 are acted upon by a force that represses in the valve closing direction. become. Therefore, the intake-side electromagnetic drive mechanism 30
Can hold the intake valve 28 in the fully closed state with a relatively small amount of exciting current. However, the exhaust-side electromagnetic drive mechanism 31 opens the exhaust valve 29 against the pressure in the cylinder 21 so that the exhaust valve 29 can be opened relatively. Requires a large amount of exciting current.

The pressure of the cylinder 21 in the exhaust stroke decreases as the combustion pressure generated in the expansion stroke decreases, and increases as the combustion pressure generated in the expansion stroke increases. Therefore, in the present embodiment, when applying an exciting current to the intake-side electromagnetic drive mechanism 30 to maintain the intake valve 28 of the cylinder 21 in the exhaust stroke in the fully closed state, the CPU 401 performs acceleration in the immediately preceding expansion stroke. The amount of excitation current was increased as the engine rotation fluctuation on the engine side became smaller, and the amount of excitation current was decreased as the engine rotation fluctuation on the acceleration side during the immediately preceding expansion stroke became larger.

On the other hand, when the excitation current is applied to the exhaust-side electromagnetic drive mechanism 31 to open the exhaust valve 29 of the cylinder 21 in the exhaust stroke, the CPU 401 detects the fluctuation of the engine rotation on the acceleration side in the immediately preceding expansion stroke. The smaller the value, the smaller the amount of the exciting current, and the larger the fluctuation of the engine rotation on the acceleration side in the immediately preceding expansion stroke, the larger the amount of the exciting current.

Specifically, the CPU 401 determines the amount of exciting current to be applied to the exhaust-side electromagnetic drive mechanism 31 according to the exciting current amount control routine during the exhaust stroke as shown in FIG. The excitation current amount control routine during the exhaust stroke
This is a routine stored in 402 and is repeatedly executed by the CPU 401 at predetermined time intervals.

In the exhaust stroke excitation current amount control routine,
First, in S401, the CPU 401 reads an output signal of the crank position sensor 51. In S402, the CPU 401 determines from the output signal of the crank position sensor 51 read in S401 whether or not the cylinder 21 at the compression top dead center exists.

If it is determined in step S402 that the cylinder 21 at the compression top dead center does not exist, the CPU 401
Terminates the execution of this routine once. On the other hand, S4
If it is determined in 02 that the cylinder 21 at the compression top dead center exists, the CPU 401 proceeds to S403.

In S403, the CPU 401 indicates 30 ° CA after the compression top dead center of the cylinder 21 from the time when the crank position sensor 51 outputs the pulse signal indicating the compression top dead center of the cylinder 21 determined in S402. The time required to output the pulse signal: T, that is, the time required for the crankshaft 23 to rotate from the compression top dead center of the cylinder 21 to 30 ° CA after the compression top dead center: T is calculated.

In step S404, the CPU 401 determines that the crankshaft 23 has reached the compression top dead center during the previous expansion stroke of the cylinder 21 (or during the expansion stroke of another cylinder 21 in which combustion was performed immediately before the cylinder 21). Time required to rotate from (TDC) to 30 ° CA after compression top dead center: Tb is set to R
Read from AM403.

In S405, the CPU 401 executes the processing in S4
03: Time calculated in T: RAM 40 in S404
It is determined whether or not the time read from No. 3 is equal to Tb.

If it is determined in step S405 that the time: T calculated in step S403 is equal to the time read from the RAM 403 in step S404: Tb,
U401 proceeds to S409, reads the amount of exciting current applied to the exhaust-side electromagnetic drive mechanism 31 during the previous exhaust stroke of the cylinder 21 from the RAM 403, and sets the exciting current amount as it is as the current exciting current amount (for example, RAM
The previous excitation current amount stored in 403 is rewritten to the current excitation current amount). After completing the processing of S409, the CPU 401 temporarily ends the execution of this routine.

In step S409, the CPU 401 reduces the amount of current obtained by reducing the previous amount of excitation current to reduce the amount of excitation current to be applied to the exhaust-side electromagnetic drive mechanism 31 to the minimum necessary amount. It may be set as the current amount of exciting current.

On the other hand, in step S405, in step S403
If it is determined that the time calculated in step S: T and the time read from the RAM 403 in step S404: Tb are not equal, the CPU 401 proceeds to step S406, and proceeds to step S403.
It is determined whether or not the time: T calculated in step S404 is shorter than the time: Tb read from the RAM 403 in S404.

If it is determined in S406 that the time: T calculated in S403 is shorter than the time read from the RAM 403: Tb in S404, the CPU determines
At 401, it is considered that the combustion pressure generated when the air-fuel mixture has burned in the cylinder 21 is higher than the previous combustion pressure, and
Proceed to 07.

In step S407, the CPU 401 determines whether the RAM
From 03, the exciting current amount applied to the exhaust-side electromagnetic drive mechanism 31 during the previous exhaust stroke of the cylinder 21 is read, and the exciting current amount is increased and corrected to calculate a new exciting current amount.

At this time, the CPU 401 may add a predetermined amount to the previous exciting current amount, or may be determined according to the deviation between the time: T and the time: Tb. The correction amount may be added to the previous excitation current amount.

Then, the CPU 401 sets the newly calculated exciting current amount as the present exciting current amount, and ends the execution of this routine once. On the other hand, the time: T calculated in S403 in S406 is equal to the time calculated in S404.
If the CPU 401 determines that the time read from the RAM 403 is longer than Tb, the CPU 401 determines that the combustion pressure generated when the air-fuel mixture has burned in the cylinder 21 is lower than the previous combustion pressure, and proceeds to S408. .

In S408, the CPU 401 executes
From 03, the exciting current amount applied to the exhaust-side electromagnetic drive mechanism 31 during the previous exhaust stroke of the cylinder 21 is read, and the exciting current amount is reduced and corrected to calculate a new exciting current amount.

At this time, the CPU 401 may subtract a predetermined amount from the previous exciting current amount, or may be determined according to the deviation between the time: T and the time: Tb. The correction amount may be subtracted from the previous excitation current amount.

Then, the CPU 401 sets the newly calculated exciting current amount as the present exciting current amount, and once terminates the execution of this routine. Thus, the CPU 401
Executes the excitation current amount control routine during the exhaust stroke, thereby realizing the rotation fluctuation detecting means and the exciting power adjusting means according to the present invention.

Therefore, according to the excitation current control according to the present embodiment, when opening and closing the intake and exhaust valves of the cylinder 21 in the expansion stroke and the exhaust stroke, the engine rotation fluctuation at the beginning of the expansion stroke is used as a parameter. By determining the excitation current amounts of the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31, the intake-side electromagnetic drive mechanism can be operated with a minimum necessary excitation current amount corresponding to the actual combustion pressure generated in each cylinder 21. 30 and the exhaust-side electromagnetic drive mechanism 31 can be operated, an unnecessary increase in the amount of current consumption due to the application of an excessive amount of exciting current, and the intake valve 28 and the exhaust valve 29 due to insufficient amount of exciting current. Will be prevented from malfunctioning.

[0090]

In the internal combustion engine having the electromagnetically driven valve according to the present invention, the engine rotation fluctuation having a strong correlation with the combustion pressure generated when the air-fuel mixture burns in each cylinder is applied to the electromagnetically driven mechanism as a parameter. The amount of exciting power to be adjusted is adjusted.

As a result, the electromagnetic drive mechanism can drive the intake valve and the exhaust valve with the minimum necessary excitation power corresponding to the magnitude of the actual combustion pressure generated in each cylinder. Therefore, according to the internal combustion engine having the electromagnetically driven valve according to the present invention, no excessive excitation power is applied to the electromagnetic drive mechanism, and the excitation power applied to the electromagnetic drive mechanism does not run short. The intake and exhaust valves can be operated accurately while preventing unnecessary increase in power consumption.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine having an electromagnetically driven valve according to the present invention.

FIG. 2 is a diagram showing a configuration of an intake-side electromagnetic drive mechanism.

FIG. 3 is a block diagram showing an internal configuration of an ECU.

FIG. 4 is a flowchart illustrating an excitation current amount control routine during an exhaust stroke.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 20 ... ECU 26 ... Intake port 27 ... Exhaust port 28 ... Intake valve 29 ... Exhaust valve 30 ... Intake side electromagnetic drive mechanism 31 ... Exhaust Side electromagnetic drive mechanism 33 ... intake branch pipe 34 ... surge tank 35 ... intake pipe 36 ... air cleaner box 39 ... throttle valve 40 ... throttle actuator 41 ... throttle position sensor 42 ... accelerator pedal 43 ... accelerator position sensor 49 ... catalyst temperature sensor

Claims (2)

[Claims] 1. An electromagnetic drive mechanism for opening and closing an intake valve and an exhaust valve of an internal combustion engine using an electromagnetic force generated when excitation power is applied, and a rotation fluctuation detection for detecting a rotation fluctuation of the internal combustion engine. An internal combustion engine having an electromagnetically driven valve, comprising: an exciting power adjusting means for adjusting the magnitude of the exciting power to be applied to the electromagnetic driving mechanism in accordance with a value detected by the rotation fluctuation detecting means. . 2. When the excitation power adjusting means applies excitation power to the electromagnetic drive mechanism after the air-fuel mixture is burned in each cylinder of the internal combustion engine, the air-fuel mixture is burned in each cylinder. 2. An internal combustion engine having an electromagnetically driven valve according to claim 1, wherein the magnitude of the exciting power to be applied to said electromagnetically driven mechanism is adjusted based on a detected value of said rotation fluctuation detecting means immediately thereafter.