JPH03134226A - Swirl control device of engine - Google Patents

Abstract

PURPOSE:To well perform combustion in an operation region with swirl ratio continuously controlled in accordance with an engine load by shielding a swirl control valve one end of its valve unit brought into contact with a circular arc surface of a valve port in a predetermined opening range. CONSTITUTION:One side of a valve port 7 is formed by a circular arc surface 7b of predetermined radius of curvature. A swirl control valve 10 is set up so that one end of its valve unit 10b is brought into contact with the circular arc surface 7b with the valve 10 opened and closed while being shielded in a range of predetermined opening alpha. Here the control valve 10 is opened and closed by an actuator 12, in which a suction negative pressure in accordance with an engine load is introduced, through a link 11. In this way, during the time of the predetermined opening alpha, a drift current S is generated so as to hold large swirl ratio by opening in the other end part of the valve unit 10b further with the swirl control valve 10 continuously variably controlled, and good combustion is obtained at the time of a partial load.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a swirl control device that is provided immediately before an intake port in a vehicle engine and variably controls the swirl state of intake air.

[Conventional technology]

In general, in vehicle engines, lean burn has a large effect on fuel efficiency and exhaust gas purification, but in lean burn, the flow of the air-fuel mixture in the combustion chamber has a large influence on combustion, especially under partial load conditions. Therefore, a swirl control valve is installed just before the intake port, and when the load is low and the intake air amount is relatively small, the swirl control valve is closed to increase the flow velocity of the intake air and cause it to drift, creating a strong swirl (eddy current) inside the cylinder. It has been proposed to improve combustion by

Conventionally, there is a prior art related to this type of engine swirl control device, for example, as disclosed in Japanese Patent Application Laid-Open No. 116027/1983. Here, a butterfly-shaped valve with a part cut out is provided in the intake port, and the supporting shaft of this valve is connected to a step motor.

It has been shown that the control unit determines the engine operating state based on various information, and when the load is low, the valve opening is reduced to improve fuel atomization and to strengthen the generation of vortex flow.

[Problem to be solved by the invention]

By the way, since the above-mentioned prior art has a configuration in which only a butterfly-shaped valve is provided in the intake port, the edge of the valve opposite to the notch contacts the inner wall of the port and closes when the load is low. If there is, the drifting effect will be large. However, if the valve opens even a little, the leakage flow from around the edge opposite to the notch will increase the opening area of the valve, as shown by the dotted line in Figure 2, and the drift effect will be significantly reduced. . Therefore, it is difficult to perform control so as to obtain a drifting effect in the partial load range. Furthermore, since the valve is opened and closed by driving a step motor using an electric signal, the structure becomes complicated.

The present invention has been made in view of the above points, and its object is to continuously control the swirl ratio according to the engine load, and to provide an engine capable of achieving good combustion in the engine operating range. The object of the present invention is to provide a swirl control device.

[Means to solve the problem]

In order to achieve the above object, an engine swirl control device of the present invention includes a swirl control valve provided at a valve port immediately before an intake port of a cylinder head. The valve body of the swirl control valve is formed of an arcuate surface and is installed so that it opens and closes while being shielded with one end in contact with the arcuate surface within a predetermined opening range.

[For production]

Based on the above configuration, the swirl control valve provided at the valve port immediately before the intake port is opened and closed via the link by an actuator to which intake negative pressure corresponding to the engine load is introduced. Since one end of the valve body of the swirl control valve is shielded in contact with the arcuate surface of the valve boat, the flow is deflected so as to maintain a large swirl ratio during a predetermined opening degree depending on the opening degree of the other end of the valve body. In addition, the swirl control valve is continuously and variably controlled so that good combustion can be obtained at partial load.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1(a) and 1(b), reference numeral 1 indicates a cylinder head, and 2 indicates a combustion chamber. A Siamese intake port 3 communicates with the combustion chamber 2 via two intake valves 4 and 5. There is. Therefore, a valve body 6 is installed just before the intake port 3 of the cylinder head l, a valve port 7 that communicates with the intake port 3 is opened in the valve body 6, and a swirl control valve 1o is housed and installed inside the valve boat 7. be done.

The valve port 7 has a rectangular cross section as shown in FIG. 1(b),
In plan view, as shown in FIG. 1(a), one side has a straight wall surface 7a, while the other side has a circular arc surface 7 curved outward with a radius of curvature r.
b.

The swirl control valve 10 includes a butterfly-shaped valve body 10b attached to a valve shaft 10a that penetrates through the center of the valve port 7, and the width of the valve body 10b is the same as the opening of the valve port 7. On the other hand, the length of the valve body 10b is set to 12, which is shorter than the maximum width 11 of the valve port 7, and the valve shaft 10a is set such that one end is always in contact with the arc surface 7b and the other end is in contact with the surface 7a with a gap γ.
Mounted eccentrically.

The valve shaft 10a of the swirl control valve 1o is connected to the link 11.
connected to the diaphragm actuator 12 via the
A negative pressure chamber 12a of this actuator 12 communicates with an intake manifold 14 via a passage 13.

Here, when the suction negative pressure at low load is large, the valve body tob of the swirl control valve 10 is positioned approximately perpendicular to the axis of the valve port 7, and the valve body 10b is moved counterclockwise as the load increases. It is designed to rotate.

Next, the operation of the engine swirl control device configured as described above will be described using the characteristic diagram shown in FIG.

First, when the engine is under low load, the suction negative pressure is large;
Actuator 12. Due to the link 11, the valve body tob of the swirl control valve 0 is located at a position A that is substantially perpendicular to the axis of the valve boat 7. One end of the valve body 10b is in contact with the arcuate surface 7b and is completely shielded, and the other end has the minimum opening area, so that the air sucked from the intake manifold 14 is directed to the surface 7a on one side by the valve body tob. deflected in the direction Therefore, this biased flow S flows along the wall surface on one side of the intake port 3, and flows into the cylinder tangentially mainly by the intake valve 5, producing a strong swirl. Next, when the load increases, the valve body 10b of the swirl control valve 10 rotates due to a decrease in the suction negative pressure, gradually increasing its opening degree, and promoting an increase in the amount of suction air. In this case, the valve body 10b is
At the opening degree α from position B to position B, one end of the valve body LOb continues to be shielded by the circular arc surface 7b, so as shown in FIG. 2, the amount of change in the opening area of the swirl control valve IO is small, and the swirl ratio The change is small, and the intake air is fed to the valve body LO.
The beam is deflected by b in the same manner as described above, and a large swirl ratio is obtained.

In this way, a strong swirl flow is generated in the cylinder due to the large swirl ratio e over the range of the opening degree α of the swirl control valve 10, making it possible to achieve good combustion at partial load, and to achieve particularly lean combustion. Effective for improving combustion.

When the engine load further increases, the valve element fob rotates, increasing the opening area of the swirl control valve 10 and reducing the drift effect. As a result, a large amount of intake air flows into the cylinder via the two intake valves 4 and 5 with low intake resistance.

The embodiments of the present invention have been described above, but the opening degree of the swirl control valve 10 can also be controlled by the engine load and other factors, and the present invention is also applicable to the case where there is only one intake valve. It is possible.

〔Effect of the invention〕

As described above, according to the present invention, in swirl control of an engine, since the change in opening area of the swirl control valve is small within a predetermined opening range, a large swirl ratio can be obtained, and combustion can be improved at partial load. can be done.

Further, in the swirl control valve, one side of the valve body is shielded by the arcuate surface of the valve port, so that the swirl ratio can be appropriately controlled variably by the valve opening degree, and the structure is also simplified. Further, the swirl ratio can be optimally controlled within the shielding range of the valve body.

Furthermore, since the valve boat and the valve body of the swirl control valve have a rectangular cross-sectional shape, the amount of intake air can also be appropriately controlled.

[Brief explanation of the drawing]

FIG. 1(a) is a block diagram showing the control system of an embodiment of the engine swirl control device of the present invention, FIG. 1(b) is a sectional view of the same essential part, and FIG. 2 is the opening degree and swirl ratio of the swirl control valve. FIG. ■...Cylinder head, 3...Intake port, 7...
・Valve port, 7b...Circular surface, IO...Swirl control valve, tob...Valve body, 11...Link, 12...
・Actuator diagram 2

Claims (3)

[Claims] (1) In a swirl control device in which a swirl control valve is provided at a valve port immediately before an intake port of a cylinder head, one side of the valve port is formed by an arcuate surface with a predetermined radius of curvature, and the valve body of the swirl control valve is . An engine swirl control device, characterized in that the engine swirl control device is installed so that one end thereof is shielded and opened and closed in contact with the circular arc surface within a predetermined opening degree range. (2) The swirl control device for an engine according to claim (1), wherein the swirl control valve is connected to a diaphragm actuator into which suction negative pressure is introduced via a link. (3) Claim (1) characterized in that the valve port is formed to have a square cross section, the valve body of the swirl control valve is also a square butterfly type, and the valve body is mounted eccentrically with respect to the valve shaft. Swirl control device for the engine described.