JPH0816443B2 - Intake and exhaust structure of internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine having a simplified intake / exhaust valve structure for a four-cycle internal combustion engine and reducing passage resistance associated with intake and exhaust.

[Prior art]

A conventional internal combustion engine employs a system in which an umbrella-type intake valve and an exhaust valve are respectively arranged in an intake passage and an exhaust passage of a cylinder head, and these are operated independently to form an intake / exhaust stroke. Further, in order to reduce intake and exhaust time and intake and exhaust resistance with the increase in speed and output of the internal combustion engine,
So-called 4 with 2 intake valves and 2 exhaust valves
A valve type has been developed and has been quite effective.

However, in the above-mentioned internal combustion engine, the intake valve is used exclusively for intake air, and the exhaust valve is used exclusively for exhaust air, which has the following problems.

(1) Since the passage area in the intake / exhaust valve portion is small, a large pressure loss occurs when the intake air flows into the cylinder or when the exhaust gas flows out from the cylinder, which appears as so-called pump work loss, which lowers the efficiency of the engine. There is.

(2) In the conventional intake / exhaust type internal combustion engine, since the exhaust valve is used exclusively for exhaust, when the intake / exhaust valve overlaps, the scavenging action by intake air is performed, but the exhaust valve However, there is a problem that the exhaust valve is always exposed to the high temperature gas because the effective cooling cannot be performed.

The fact that the exhaust valve is constantly exposed to high temperatures reduces the sealing property and durability of the exhaust valve.

(3) Further, the four-valve system has a problem that the structure of the cylinder head and the system of the valve system are remarkably complicated, and high precision parts are required.

In addition, the intake / exhaust port that is formed in the cylinder head, the intake / exhaust valve that is arranged to open and close between the intake / exhaust port and the inside of the cylinder, and the intake / exhaust valve that are shared in the exhaust stroke and the intake stroke. A valve mechanism that opens the valve for a predetermined period of time continuously, an intake control valve that is arranged between the intake / exhaust / exhaust port and the intake passage, and opens / closes according to the pressure difference between the intake / exhaust port and the intake / exhaust port. An intake / exhaust device for a four-cycle engine, which is provided between the exhaust passage and an exhaust control valve that opens and closes in accordance with the pressure difference between the two, is disclosed in Japanese Patent Laid-Open No. 59-59.
It is proposed by Japanese Patent No. 153907.

However, this intake / exhaust device uses a butterfly valve that opens and closes according to the pressure difference as a valve for performing intake and exhaust, and the valve is extremely complicated and the drive source of the valve is intake. Is not reliable because it is the pressure difference between
The opening / closing operation is inaccurate and cannot be used in an actual device.

According to Japanese Patent Publication No. 35-16251, a bell-shaped outer valve is provided in the center of the cylinder head, and an umbrella-shaped inner valve is provided inside the outer valve, and the valve seat of this inner valve is located below the outer valve.
The valve seats of the outer valve are formed on the cylinder head side, respectively, the outer valve is seated and closed, the inner valve is opened and exhausted, the outer valve is lowered and the opening of the outer valve is stopped in the lowered position. It has been proposed that the valve seat portion that was closed by the outer valve is opened and the intake is performed by opening the valve seat portion.

However, this intake / exhaust valve device has the following essential problems. That is, in an internal combustion engine, it is usually important to minimize the number of valves because the combustion chamber is exposed to high temperature combustion gas of 2000 ° C. or higher and high pressure combustion gas of 15 MPa or higher. However, in this prior art structure, two bell-shaped outer valves and an umbrella-shaped inner valve are used.
It is necessary to arrange the valves of the book in double and to operate them by stacking them.

Therefore, the positioning accuracy of the two valves is very highly required. This inevitably results in a device with poor reliability as a valve for sealing high temperature and high pressure combustion gas.

Further, the umbrella-shaped valve that opens and closes the exhaust passage cools the valve seat provided on the cylinder head in an ordinary internal combustion engine and cools it through the valve seat during the seating period of the valve. However, since the umbrella-shaped valve in this prior art abuts the inside of the lower end of the bell-shaped valve, it is substantially difficult to cool the umbrella-shaped valve.

Further, in a 4-cycle engine, it is necessary to make a large intake / exhaust passage, but in the prior art, it is necessary to form an exhaust passage inside a ring-shaped intake passage. When the diameter is small, the intake passage is reduced by the area of the exhaust passage, which inevitably causes a large pumping loss, which causes an essential problem that engine performance is deteriorated.

[Object of the Invention]

The present invention has been achieved in order to solve the problems of the internal combustion engine in which the conventional intake valve and exhaust valve are provided in the cylinder head, respectively, and a large intake port or exhaust port opened and closed by the valve is provided. (EN) An internal combustion engine in which intake is performed and exhaust is quickly performed with a small resistance by opening to reduce pump work loss as much as possible and improve efficiency.

Another object is to provide an internal combustion engine in which the exhaust valve is not always exposed to high temperatures and the exhaust valve has excellent sealability and durability.

Still another object is to provide an internal combustion engine with a simple valve drive mechanism and few failures.

[Outline of Invention]

Means for Solving the Problems The present invention for achieving the above object includes a single umbrella-shaped main valve that opens and closes the top of a combustion chamber, a switching chamber that is located behind the main valve and that is opened and closed by the main valve, and this switching. A swirl-shaped intake passage that is connected to the chamber and surrounds the main valve and that is disposed near the combustion chamber, and an exhaust passage that is disposed adjacent to this intake passage are formed above and below the combustion chamber, respectively. A cylindrical intake and exhaust control valve that surrounds the valve shaft of the main valve that alternately contacts the valve seat formed in the intake passage and the valve seat formed in the exhaust passage to alternately open and close the intake passage and the exhaust passage. The intake / exhaust control valve is an intake / exhaust structure of an internal combustion engine configured to come into contact with intake air during intake.

That is, in the present invention, one umbrella-type main valve is provided in the center of the cylinder head, and this main valve serves both as an intake valve and an exhaust valve in a conventional internal combustion engine.

An intake / exhaust control valve is provided around the main valve as a valve for switching between intake and exhaust. This intake / exhaust control valve is formed in a cylindrical shape and slides and seals on the surface of the cylindrical part to form abutting parts, that is, valve parts at both ends of the cylindrical part. The intake passage is opened at the position of, and the exhaust passage is opened at two positions of the information.

When the cylindrical control valve is seated downward, the upper chamber of the main valve communicates with the exhaust passage, and when it is seated upward, the upper chamber of the main valve communicates with the intake passage. It is configured.

Therefore, the cylindrical intake / exhaust control valve can reciprocate as if the piston reciprocates in the cylinder to alternately open and close the intake passage and the exhaust passage.

Further, the main valve and the intake / exhaust control valve are hydraulically driven by a cylinder device or mechanically driven.

According to the internal combustion engine of the present invention, the combustion chamber is opened / closed by one main valve, and the intake / exhaust control valve provided around the main valve is greatly opened by moving away from the combustion chamber to minimize the fluid resistance. The intake passage is formed, and fresh air is swirled in from around the main valve. Further, when the cylindrical intake / exhaust control valve closes the intake passage, the exhaust passage opens in a chimney shape, so that exhaust resistance can be minimized and exhaust can be performed.

Since one main valve is used, the intake and exhaust can be efficiently arranged in the combustion chamber so that the intake and exhaust paths can be simplified.

Also, since the main valve and the intake / exhaust control valve are arranged in a straight line in the front and rear, a large area of the intake / exhaust passage can be secured. Therefore, the cooling can be effectively performed.

〔Example〕

 Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a main part of a four-cycle internal combustion engine,
FIG. 2 is a cross-sectional view showing the intake / exhaust control valve and the spiral intake passage in FIG.

A cylinder head 3 is provided above a cylinder block 2 in which a piston 1 is slidably accommodated in a cylinder. An umbrella-shaped main valve 4 is provided in the center of the cylinder head 3, and an intake / exhaust is provided by surrounding the main valve 4. A control valve 5 is provided. A passage communicating with the intake port 6 is provided below the range in which the intake / exhaust control valve 5 moves up and down, and a passage communicating with the exhaust port 7 is provided above. A switching chamber 3a is formed at a place where the two passages are combined, that is, on the back surface of the main valve 4.

The intake / exhaust control valve 5 has a cylindrical valve portion 5a and two or three plate-shaped support portions 5b radially extending inward of the valve portion 5a.
And a cylindrical shaft portion 5c provided at the end of the support portion 5b.
And a piston portion 5d provided so as to project from the end of the shaft portion 5c. A guide surface in the middle of the switching chamber 3a
3b, valve seats 3c, 3d are formed on the upper and lower sides, respectively, and the cylindrical valve portion 5a is guided by the shaft portion 5c, and the contact portions provided on the upper and lower sides of the valve portion 5a are alternately arranged on the valve seats 3c, 3d. Seated to alternately open and close the intake passage and the exhaust passage.

Therefore, when the intake / exhaust control valve 5 is lowered as shown in FIG. 1, the contact portion formed at the lower end of the valve portion 5a is the valve seat 3c.
When the seat is seated on the seat, the exhaust passage leading to the exhaust port 7 is opened, and the ascending portion formed at the upper end of the valve portion 5a is in the raised state, the seat portion is seated on the valve seat.
The seat 3d is seated to open the intake passage leading to the intake port 6.

The shaft portion 5c of the intake / exhaust control valve 5 is formed in a cylindrical shape, and the inner surface thereof slidably supports the valve shaft 4a of the main valve 4, and the shaft portion 5c functions as a bearing of the main valve 4. ing.

A cylinder device 8 for operating the main valve 4 and the intake / exhaust control valve 5 is provided above the cylinder head 3. In the lower portion of the cylinder device 8, a piston portion 5d formed at the end of the shaft portion 5c of the intake / exhaust control valve 5 is housed. A piston 4b is fixed to the shaft portion 4a of the main valve 4, and an air spring 9 is formed between the piston 4b and the piston portion 5d. It gives the power to move. Compressed air having a predetermined pressure is supplied to the air spring 9. Further, the valve shaft 4a is provided at the upper end of the cylinder device 8.
Is formed as a plunger device 8a.

The intake / exhaust control valve 5 and the main valve 4 are hydraulically driven in the present embodiment, and the piston portion 5d of the intake / exhaust control valve 5 supplies the high hydraulic pressure generated by the plunger 11 operated by the cam 10 via the pipe 12. Operates with the supplied hydraulic pressure. In addition, the main valve 4
The hydraulic pressure for operating is supplied via a pipe 15 with a high pressure generated by a plunger 14 operated by a cam 13.

Next, the operation of the internal combustion engine according to the present invention will be described.

FIG. 3 is a diagram showing each process of 4 cycles,
(A) The figure shows the [expansion stroke]. Before the exhaust stroke begins, the intake / exhaust control valve 5 is operated to close the intake passage leading to the intake port 6 and open the exhaust passage 7. Become.

The figure (b) shows the state where the main valve 4 is opened and the [exhaust stroke] is started from the state of the above-mentioned figure (a).

(C) In the figure, the intake / exhaust control valve 5 is raised to close the exhaust passage and open the intake passage to complete the [exhaust stroke],
The state where the [intake stroke] is started is shown.

The diagram (d) shows a state in which the main valve 4 is closed and the [intake stroke] is completed. Next, the piston is raised to shift to the compression stroke, and then the state shown in the above-mentioned FIG.

FIG. 4 is a diagram showing the relationship between the intake or exhaust passage area and the crank angle, and FIG. 3 shows (a) to (a) on the horizontal axis.
The position of each process of (d) is shown.

In FIG. 4, a curve (a) shows a change in the opening area of the intake passage, a curve (a) shows a change in the opening area of the exhaust passage, and (c) shows a change in the valve area of the main valve.

The hatched area (d) in the drawing indicates the effective exhaust valve passage area, and the shaded area (e) indicates the intake effective passage area.

FIG. 5 shows a pressure in a cylinder of an internal combustion engine according to the present invention equipped with a supercharger-a volume diagram, and FIG. 6 shows a pressure in a cylinder of a conventional internal combustion engine in which an intake valve and an exhaust valve are independent- It is a volume diagram.

In FIG. 5 and FIG. 6, the part of the loop moving from right to left shows (-) work for the piston, and the part of moving left to right shows (+) work, and is surrounded by the loop. The area that is shown means the exhaust gas recovery energy.

Now, in the present invention shown in FIG. 5, the area in the loop is increased in spite of the same supply / exhaust pressure difference as in the conventional example shown in FIG.

This means that the exhaust gas recovery energy in the supercharger is directly taken out as a power with almost no loss, and the efficiency of the engine is increased accordingly.

〔The invention's effect〕

The intake / exhaust structure for an internal combustion engine according to the present invention includes a single umbrella-shaped main valve 4 that opens and closes the top of a combustion chamber, and a switching chamber that is located behind the main valve 4 and that is opened and closed by the main valve 4. 3a, a spiral intake passage 6 which is connected to the switching chamber 3a and surrounds the main valve 4 and is arranged near the combustion chamber, and an exhaust passage 7 which is arranged adjacent to the intake passage 6 A valve seat 3c formed in the intake passage 6 and an exhaust passage 7
Alternately abuts the valve seat 3d formed in the intake passage 6 and the exhaust passage 7
A cylindrical intake / exhaust control valve 5 is provided so as to surround the valve shaft 4a of the main valve 4 that alternately opens and closes, and the intake / exhaust control valve 5 is configured to come into contact with intake during intake. It is possible to exert an effect.

(1) Since one umbrella-shaped main valve 4 is used to perform the functions of both the intake valve and the exhaust valve, when the opening diameters of the intake and exhaust holes that open in the upper part of the combustion chamber are the same, a large size The main valve 4 can be used, and as compared with FIG. 5 and FIG. 6, the exhaust gas recovery energy obtained by the supercharger can be directly taken out as a power with almost no loss. Conversely, since there is no pump work loss, the efficiency of the engine is improved accordingly.

(2) Since the main valve 4 serves both as an intake valve and an exhaust valve, even if the main valve 4 is heated in the exhaust stroke, the main valve 4 is contacted with the passing intake air in the intake stroke and cooled.
The sealing property and durability are improved.

(3) Since the cylindrical supply / exhaust control valve 5 is provided in the switching chamber 3a provided with the main valve 4 to switch the exhaust passage to the exhaust port 7 and the intake passage to the intake port 6 alternately, The structure of the valve 5 and the mechanism for driving it can be simplified.

Particularly, in the present invention, the supply / exhaust control valve 5 is brought into contact with the valve seat 3d formed in the exhaust passage and the valve seat 3c formed in the intake passage, and the outer peripheral surface is also brought into contact with the guide surface 3b. The intake / exhaust control valve 5 can be effectively cooled from the 3 side.

(4) Since only one valve is required at the top of the combustion chamber,
The design of the intake path is facilitated, and the structure capable of generating the optimum swirl can be easily achieved.

(5) Since the structure of the cylinder head is simplified,
An internal combustion engine with high reliability can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a cylinder head portion of an internal combustion engine according to the present invention, and FIG. 2 is an intake passage (switching chamber) of an intake / exhaust control valve portion.
FIG. FIG. 3 is an explanatory view of the movements of the main valve and the intake / exhaust control valve, and FIG. 4 is a view showing changes with time of the intake / exhaust passage area of the cylinder. FIG. 5 is a cylinder pressure-volume diagram of an internal combustion engine with a supercharger according to the present invention, and FIG. 6 is a similar view of a conventional internal combustion engine with a supercharger. 1 ... Piston, 2 ... Cylinder block, 3 ... Cylinder head, 3a ... Switching chamber, 3b ... Guide surface, 3c, 3d ...
Valve seat, 4 ... Main valve, 4a ... Shaft, 4b ... Piston, 5 ...
… Intake / exhaust control valve, 5a …… Valve part, 5b …… Support part, 5c …… Shaft part, 5d …… Piston part, 6 …… Intake port, 7 …… Exhaust port,
8 ... Cylinder device, 8a ... Plunger device, 9 ... Air spring, 10 ... Cam, 11 ... Plunger, 12 ... Piping,
13 …… Cam, 14 …… Plunger, 15 …… Piping.

Claims (1)

[Claims] 1. An umbrella-shaped main valve (4) that opens and closes the top of a combustion chamber, and a switching chamber (behind the main valve (4) that is opened and closed by the main valve (4). 3a), a spiral intake passage (6) which is connected to the switching chamber (3a), surrounds the main valve (4), and is arranged near the combustion chamber, and the intake passage (6).
And an exhaust passage (7) arranged adjacent to the exhaust passage (7) above and below the combustion chamber, respectively, and a valve seat (3c) formed in the intake passage (6) and a valve seat formed in the exhaust passage (7). (3d) Cylindrical intake / exhaust control valve (around the valve shaft (4a) of the main valve (4) that alternately contacts the intake passage (6) and the exhaust passage (7). 5) is provided, and the intake / exhaust control valve (5) is an intake / exhaust structure for an internal combustion engine configured to come into contact with intake during intake.