JPH06193415A - Intake valve control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an intake valve control device of an internal combustion engine devised to provide the optimum valve opening characteristic of an intake valve in accordance with a driving state of the internal combustion engine. CONSTITUTION:By furnishing a first intake valve 9a and a second intake valve 9b for each cylinder, freely setting an valve opening characteristic of the first intake valve 9a through an electromagnetic driving member 13 in accordance with a signal of an electronic control circuit 40 and switching actuation/non- actuation of the second intake valve 9b by an oscillating fulcrum supporting device 21, it is possible to provide the optimum valve opening characteristic of the intake valves 9a, 9b in accordance with an engine driving state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake valve control device for an internal combustion engine. In particular, the present invention relates to an intake valve control device for an internal combustion engine having two intake valves in one cylinder.

[0002]

2. Description of the Related Art An internal combustion engine for an automobile has two cylinders.
A so-called DOHC type engine equipped with one intake valve and one exhaust valve is common. In such an internal combustion engine, since the intake passage and the combustion chamber communicate with each other via the two intake valves, the cross-sectional area of the communication passage can be increased, so that a large amount of air can be sucked in the high speed operation range, and the suction efficiency can be improved. Can be improved.

However, when such an internal combustion engine is operated in the low speed rotation range, the intake air amount becomes small, so this small intake air amount is sucked into the combustion chamber through the communication passage having a large cross-sectional area. The problem that a good mixture cannot be formed in the combustion chamber because the flow velocity of
The problem of so-called intake blow-through in which the intake air sucked into the combustion chamber escapes to the outside of the combustion chamber via the intake valve and the exhaust valve is likely to occur.
The drivability and filling efficiency of the engine are reduced.

[0004]

In order to solve such a problem, a low speed rotation cam for opening and closing two intake valves and a high speed rotation cam are formed on the cam shaft, and one of them is provided in the low speed rotation range. Japanese Patent Publication No. 3-51886 proposes that the opening and closing angle (operating crank angle) of the intake valve is made small and the opening and closing angle of the other intake valve is made large.

However, in such an engine, a cam for low speed rotation and a cam for high speed rotation are formed on the cam shaft, and the two intake valves are opened / closed in synchronization with the rotation of the engine, so that it corresponds to each operating state of the engine. It was difficult to perform the optimum intake valve opening / closing control with high accuracy. The present invention has been made in view of such conventional problems, and is adapted to obtain the optimum valve opening characteristic of the intake valve according to each operating state of the internal combustion engine,
Especially in the low speed range, the intake valve control of the internal combustion engine is designed to improve the intake air velocity into the combustion chamber to improve the formation of the air-fuel mixture in the combustion chamber and prevent the intake air from passing through to improve the charging efficiency. The purpose is to provide a device.

[0006]

Therefore, the intake valve control device for an internal combustion engine according to the present invention is provided with a first intake valve and a second intake valve for each cylinder, and the first intake valve is opened by an electromagnetic mechanism. The valve characteristics are variable, and it is driven freely to switch between operation and non-operation.
The intake valve has a structure in which driving force is transmitted to a mechanism interlocked with the engine rotation so that it can be switched between operation and non-operation, and it is freely driven to switch between operating and non-operating, while operating state detecting means for detecting the operating state of the engine, And a valve operation control means for controlling the operation of the first intake valve and the second intake valve according to the operating state detected by the operating state detecting means.

Further, an operating condition detecting means for detecting the operating condition of the first intake valve is provided so that the second intake valve is operated in the entire operating range when the defective operation of the first intake valve is detected. It may be controlled.

[0008]

According to the structure of such an intake valve control device, the valve operation control means controls the energization time to the electromagnetic mechanism to arbitrarily set the valve opening characteristic of the first intake valve and to change the engine rotation speed. Operation of the second intake valve that opens and closes in synchronization
The non-operation can be arbitrarily switched according to the engine operating state.

In addition, when a failure occurs in the first intake valve, the second intake valve can be forcibly operated in the entire operating range.

[0010]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a view of a cylinder head 2 of a 4-cycle multi-cylinder internal combustion engine 1 for one cylinder as viewed from below. As shown in this figure, two intake valves 9 a and 9 b and two exhaust valves 10 are formed facing the combustion chamber 6. 2 and 3 show vertical cross-sections of the cylinder head 2. The cylinder head 2 is provided with an intake passage 7 and an exhaust passage 8 which communicate with the combustion chamber 6, and the combustion chamber 6 is ignited. A stopper 15 is provided. Further, a fuel injection valve 5 is provided in the combustion chamber 6, and a fuel amount corresponding to the intake air amount is supplied to the engine 1. An exhaust pipe (not shown) is provided downstream of the exhaust passage 8.

Communication passages (intake ports) 7a and 7b between the intake passage 7 and the combustion chamber 6 are opened and closed by two intake valves 9 arranged side by side, that is, a first intake valve 9a and a second intake valve 9b. The first intake valve 9a and the second intake valve 9b are slidably fitted on the inner circumferences of the valve guides 11a and 11b, respectively, and the intake ports 7a and 9b are closed by the valve springs 12a and 12b.
It is urged in the direction of closing 7b.

Above the first intake valve 9a, the solenoid 1
Electromagnetic drive member 13 including 3a and plunger 13b
Is provided, and when a voltage is applied to the solenoid 13a, the plunger 13b moves downward in the figure, and the first intake valve 9a
Is pressed to open the first intake valve 9a. As shown in FIG. 4, a signal from a crank angle sensor 31, an air flow meter 32, a water temperature sensor 33, etc. (these constitute an engine operating state detecting means) is supplied to an electronic control circuit 40 constituting the valve operation controlling means. Typed in agency 1
Of the operating condition (engine speed, load, engine temperature, crank angle, etc.) is detected, a control pulse is calculated based on the signal, and the solenoid 13a is energized or de-energized to operate the first intake valve 9a. Open and close control.

By the way, in this embodiment, the first intake valve 9a
The diameter of is smaller than that of the second intake valve 9b in order to improve the intake flow velocity into the combustion chamber 6 and to reduce the inertial weight, thereby reducing the size and weight. The swing fulcrum support device 21 for switching the second intake valve 9b between operating and non-operating is formed in the cam shaft 21a and the cam shaft 21a which are rotatably supported in the cam shaft hole 21c formed in the cylinder head 2. And a motor 21d for rotating the cam shaft 21a.

The camshaft 21a has a camshaft hole 2
The cam 21b is pivotally supported in the cylinder 1c, and the bottom surface of the lash adjuster 22 slidably inserted in the hole 20 formed in the cylinder head 2 is brought into contact with the bottom surface. The position of the cam shaft 21a shown by the solid line in FIGS. 3 and 4 is a state in which the cam 21b pushes the lash adjuster 22 up to the uppermost position, and the swing fulcrum support device 21 is in the operating state, that is, the second intake valve 9b is operating. It shows the state. By maintaining this state, the intake cam 3a
Is applied to the second intake valve 9b via the swing arm 24.
Then, the second intake valve 9b overcomes the biasing force of the spring 12b and opens.

A cam 21 shown by a chain line in FIGS.
The position b is in the non-operating state of the swing fulcrum support device 21, that is, in the state where the bottom surface of the lash adjuster 22 and the base circular portion of the cam 21b are in contact with each other.
Is the lowest position. Therefore, the rotational force of the intake cam 3a is not transmitted to the second intake valve 9b, and by maintaining this state, the closed state of the second intake valve 9b is maintained. By the way, the operation of the swing fulcrum support device 21
In order to smoothly switch the non-operation, the cam 21
Needless to say, the cam crest shape of b and the rotation speed at the time of switching between operation and non-operation are appropriately set according to the cam crest shape and rotation speed of the corresponding intake cam 3a.

As is well known, the opening / closing angle of the exhaust valve 10 is about 40 ° CA before bottom dead center and 10 ° CA after top dead center.
Close near. Subsequently, the operation and effect of the present embodiment having the above-mentioned configuration will be described. When the engine 1 is operated and a crank shaft (not shown) rotates, the electronic control circuit 40
Based on the output of the solenoid 1 for a predetermined period of the intake stroke.
3a is energized and the first intake valve 9a opens against the spring 12a. Therefore, the intake air is taken into the combustion chamber 6 through the intake passage 7 and the communication passage 7a. Based on the signal from the electronic control circuit 40, the valve opening characteristic of the first intake valve 9a driven via the electromagnetic drive member 13 is determined by the operating state of the engine (acceleration,
It can be set arbitrarily with high accuracy according to steady state, idle, deceleration), for example, a predetermined engine speed (eg 2000 rpm)
During steady operation of less than, the valve is opened at around 10 ° CA before top dead center to around top dead center and closed around near bottom dead center to 40 ° CA after bottom dead center.

Further, at the time of idling or at the time of light load, by opening the valve near the top dead center and closing it before the bottom dead center, the pumping loss can be reduced, and the air sucked into the combustion chamber 6 is the first. It is possible to suppress the intake blow-by that escapes via the intake valve 9a and the exhaust valve 10. Further, in this embodiment, when the engine speed is lower than a predetermined value, the swing fulcrum support device 21 is in a non-operating state, that is, the lash adjuster 22 is at the lowermost position, and the rotational force of the intake camshaft 3 is the swing arm. Not transmitted to 24, second
The intake valve 9b is maintained in the closed state. Therefore, the introduction of intake air into the combustion chamber 6 via the second intake valve 9b is blocked, so that the cross-sectional area of the intake passage can be reduced, and the intake flow velocity into the combustion chamber 6 can be improved to improve the mixture formation. You can Furthermore, when the engine is started, the startability can be improved by appropriately setting the closing timing of the first intake valve 9a.

Next, when the engine rotation speed exceeds a predetermined rotation speed, the motor 21d is rotated to activate the swing fulcrum support device 21. That is, as the motor 21d is rotated, the cam shaft 21a is rotated and fixed at a position that holds the lash adjuster 22 at the uppermost position. Therefore, the rotational force of the intake cam 3a is transmitted to the second intake valve 9b via the swing arm 24 that swings around the swing arm 24 support portion of the lash adjuster 22 as a fulcrum. Therefore,
The second intake valve 9b opens and closes in synchronization with the rotation of the intake cam 3a.

As a result, the second intake valve 9b having a relatively large diameter is provided.
Since a large amount of intake air is supplied to the combustion chamber 6 via the, the output of the engine can be increased. The opening / closing timing of the second intake valve 9b is set by the shape of the intake cam 3a, and is opened, for example, near 10 ° CA before top dead center and closed near 45 ° CA after bottom dead center. It should be noted that both the intake valves 9a and 9b are actuated together near a predetermined engine speed at which the first intake valve 9a and the second intake valve 9b are switched, so that the switching is smoothed and an output shock or the like is not generated. Is preferred.

Furthermore, during deceleration operation, it is possible to improve the effectiveness of engine braking by opening the first intake valve 9a near the top dead center and closing it after the bottom dead center.
Thus, based on the signal of the electronic drive circuit 40, the valve opening characteristic of the first intake valve 9a is arbitrarily set via the electromagnetic drive member 13, and the swing fulcrum support device 21 controls the second intake valve 9b. By switching between operating and non-operating, optimal opening / closing control of the intake valve can be performed according to the engine operating state.

Further, when the malfunction of the first intake valve 9a is detected by the operating state detecting means such as the lift sensor 34, the swing fulcrum support device 21 is operated even at a speed lower than the predetermined engine rotational speed, and the second intake air is exhausted. If the intake air is introduced into the combustion chamber 6 via the valve 9b, the vehicle can be moved to a safe place such as a repair shop. In this embodiment, since the first intake valve 9a is operated only in the low rotational speed range, the valve opening / closing acceleration can be small and the electromagnetic mechanism can be downsized, but the driving force for electromagnetic driving is increased. Alternatively, the operation may be performed over the medium rotation speed region or the entire rotation speed region. Then, when the engine is started, the second intake valve 9b is operated to deactivate the first intake valve 9a, thereby preventing increase in battery power consumption. by the way,
Although the fuel injection valve 5 is arranged in the combustion chamber 6 in this embodiment,
Even if it is provided in the intake passage 7 as conventionally known, the same operation and effect can be obtained.

[0022]

As described above, according to the intake valve control apparatus for an internal combustion engine of the present invention, it is possible to obtain the optimum valve opening characteristic of the intake valve according to the engine operating condition. For example, when the engine speed is lower than a predetermined value, the opening / closing timing of the first intake valve can be controlled accurately by driving the first intake valve via an electromagnetic mechanism, and the second intake valve can be closed. Together with this, improvement of filling efficiency by suppressing intake blow-through,
Also, by improving the intake air flow rate into the combustion chamber, it is possible to obtain a good air-fuel mixture, reduce pumping loss, improve engine performance and fuel efficiency, and improve exhaust composition. In the high rotational speed region, the passage resistance is reduced and a large amount of intake air is obtained by operating the second intake valve having a relatively large diameter or operating both the first intake valve and the second intake valve. Can be supplied to the engine to increase the output of the engine, or the characteristics of the engine braking can be improved during deceleration to extend the life of the brake lining.

On the other hand, when a malfunction of the first intake valve occurs, the second intake valve is operated in the entire rotational speed range to eliminate the complete stop of the engine, and to keep the vehicle at a safe place.
For example, it is possible to move to a repair shop or the like.

[Brief description of drawings]

FIG. 1 is a bottom view showing one cylinder of a cylinder head of a multi-cylinder internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view taken along line YY of FIG.

FIG. 4 is a configuration diagram according to an embodiment of the present invention.

FIG. 5 is a diagram showing operating regions of a first intake valve and a second intake valve according to an embodiment of the present invention.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Cylinder Head 3 Intake Cam Shaft 3a Intake Cam 9a 1st Intake Valve 9b 2nd Intake Valve 13 Electromagnetic Drive Member 13a Solenoid 13b Plunger 21 Swing Support Point Support 21a Camshaft 21b Cam 21c Camshaft Hole 21d Motor 31 Crank Angle sensor 32 Air flow meter 33 Water temperature sensor 34 Lift sensor 40 Electronic control circuit

Claims (2)

[Claims] 1. A first intake valve and a second intake valve are provided for each cylinder, and the first intake valve is driven by an electromagnetic mechanism so that the valve opening characteristics can be changed and the operation can be freely switched. While the driving force is transmitted to the mechanism interlocked with the engine rotation and can be switched between cutoffs, it can be driven freely between operation and non-operation.
Operating state detecting means for detecting an operating state of the engine; and valve operation control means for controlling the operation of the first intake valve and the second intake valve according to the operating state detected by the operating state detecting means,
An intake valve control device for an internal combustion engine, comprising: 2. An operation state detecting means for detecting an operation state of the first intake valve is provided, and when the operation failure of the first intake valve is detected, the valve operation control means is provided with the second intake air in the entire operation region. The valve is controlled so as to be activated.
An intake valve control device for an internal combustion engine according to item 1.