JPH0626411A - Intake system for internal combustion engine - Google Patents

Abstract

PURPOSE:To efficiently generate swirl in the whole of a combustion chamber by way of eliminating collision of intake air with each other by communicating intake pipes for low speed and high speed connected to intake ports for low speed and high speed and intake pipes for high speed connected to intake ports for high speed to each other by communicating pipes. CONSTITUTION:Three intake ports 3-5, 3a-5a and more than one exhaust port 6, 7, 6a, 7a are arranged facing each other on the circumference in combustion chambers 2, 2a. Thereafter, one of the three intake ports is used as intake ports 5, 5a for low speed and high speed, and the remaining two are used as intake ports 3, 4, 3a, 4a for high speed. Intake pipes 9, 9a for low speed and high speed connected to the intake ports 5, 5a for low speed and high speed and intake pipes 8, 8a for high speed connected to the suction ports 3, 4, 3a, 4a for high speed are communicated through to each other by communicating pipes 17, 17a. Consequently, flowed-in intake air does not cause collision in the combustion chambers 2, 2a, swirl is generated even in a part to the center of the combustion chambers 2, 2a and the swirl is generated in the whole of the combustion chambers 2, 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the present invention, three intake holes and two or more exhaust holes are arranged to face each other on the circumference of the combustion chamber.
The present invention relates to an intake device for an internal combustion engine in which one of the intake holes is a low speed / high speed intake hole and the other two intake holes are high speed intake holes.

[0002]

2. Description of the Related Art One cylinder has three intake valves adjacent to each other and two or more exhaust valves adjacent to each other.
In a cycle internal combustion engine, in order to prevent the fuel from adhering to the inner wall of the intake passage to form a wall surface flow, two or three intake passages communicating with the three intake valves and intake air near each intake valve are provided. A communication mixing chamber that communicates the passages, and a fuel injection valve that is provided in the communication mixing chamber and injects fuel toward the intake valve are provided. At least one intake passage is provided with a control valve that opens and closes according to operating conditions. Inspiratory devices are known. (See JP-A-59-90717). In this intake device, the control valve is closed during low load / low speed operation,
The intake air flows into the communication mixing chamber from one or two intake passages to generate a strong turbulent flow in the communication mixing chamber, but since the intake air simultaneously flows into the combustion chamber from the three intake valves with substantially the same strength, The incoming flows collided with each other in the combustion chamber, and swirls could not be efficiently generated in the entire combustion chamber.

[0003]

DISCLOSURE OF THE INVENTION According to the present invention, three intake valves adjacent to each other and two or more exhaust valves adjacent to each other are arranged in a combustion chamber so as to be opposed to each other on the circumference of a combustion chamber for one cylinder. In the internal combustion engine, when the intake air is supplied only from the low-speed / high-speed intake pipe (during idling or low-speed operation), most of the intake air is made to flow from the low-speed / high-speed intake hole by a strong flow, and the intake air An object of the present invention is to allow the remaining portion to flow in from a high-speed intake hole with a weak flow to eliminate collision of inflowing intake air in the combustion chamber and efficiently generate swirl in the entire combustion chamber.

[0004]

In order to solve the above problems, in the intake system for an internal combustion engine of the present invention, three intake holes and two or more exhaust holes are opposed to each other on the circumference of the combustion chamber. , One of the three air intake holes is used as a low speed / high speed air intake hole (low speed and high speed air intake holes), and the remaining two air intake holes are not used as high speed air intake holes. , So that the low-speed / high-speed intake pipes (low-speed and high-speed intake pipes) connected to the low-speed / high-speed intake holes and the high-speed intake pipes connected to the high-speed intake holes are connected by a communication pipe did. Then, the low-speed / high-speed intake pipe and the high-speed intake pipe are arranged so as to be inclined to each other, and by the communication pipe having a smaller diameter than the low-speed / high-speed intake pipe,
The low-speed / high-speed intake pipe is connected to the adjacent high-speed intake pipe, and the communication pipe is connected to the low-speed / high-speed intake pipe and the high-speed intake pipe outside the cylinder body.
The high-speed intake pipe is branched, one of them is communicated with the high-speed central intake hole, the other is communicated with the high-speed side intake hole, and the communication pipe is connected in the vicinity of the branched portion of the high-speed intake pipe, The intake air that has flowed from the low-speed / high-speed intake pipe to the high-speed intake pipe by the communication pipe is
It is arranged so that it flows into the combustion chamber through the valve located in the center of the individual intake valves), and the high-speed intake pipe has a straight part that communicates with the high-speed central intake hole. The portion communicating with the vehicle side intake hole can be formed in an inclined shape.

In the above construction, "on the circumference of the combustion chamber" means that the combustion chamber is arranged substantially along the circumference on a cross section cut by a substantially horizontal surface, and "inclination" Also means that they are arranged so as to incline and intersect each other when viewed on the same cross section as described above. In addition to the vaporizer, a fuel injection device can be used as the device for supplying fuel.

[0006]

[Operation] When the intake air is supplied only from the low speed / high speed intake pipe (during idling and low speed operation), most of the intake air flows into the combustion chamber through the low speed / high speed intake hole by a strong flow, The remaining part of the intake air enters the high speed intake pipe through the communication hole, and flows into the combustion chamber through the central high speed intake hole by a weak flow. The inflowing intake air does not collide with each other in the combustion chamber, and swirls also occur in a portion near the center of the combustion chamber, and swirls are generated in the entire combustion chamber. Further, in this case, the intake air does not enter the high-speed intake pipe through the communication hole, and the burnt gas does not flow backward from the intake hole to the high-speed intake pipe.

When the intake air is supplied from the low-speed / high-speed intake pipe and the high-speed intake pipe (during medium-speed operation and high-speed operation),
The intake air flows into the combustion chamber through both the low speed / high speed intake holes and the high speed intake holes, and a sufficient intake amount can be secured.

[0008]

EXAMPLE An example will be described with reference to FIG. Cylinders 1 and 1a are arranged in a cylinder body 10 of an internal combustion engine, and a high speed side intake hole 3 (3a) is provided on the circumference of the combustion chamber 2 (2a) on the circumference of the combustion chamber 2 (2a) as shown in FIG. , A high speed central intake hole 4 (4a), a low speed / high speed intake hole 5 (5a), and three exhaust holes 6 (6a) and 7 (7a) are arranged so as to face each other. ing. The three intake holes are connected to the respective intake pipes via three intake valves (not shown), and the two exhaust holes 6 (6a) and 7 (7a) are respectively connected to the two exhaust valves (see FIG. Each exhaust pipe 18 (18
a), 19 (19a).

The carburetors 11 (11a) and 12 of the internal combustion engine have piston valves 13 (13) that move up and down in response to negative pressure.
a) and 14 and throttle valves 15 (15a) and 16 are provided, respectively. The carburetor 11 (11a) is connected to the high-speed intake pipe 8 (8a), and the end portion (the right end portion in FIG. 1) of the high-speed intake pipe 8 (8a) is branched as illustrated to form two connection holes 20 ( 20a) and 21 (21a), the connection hole 20 (20a) communicates with the high speed side intake hole 3 (3a), and the connection hole 21 (21a) is connected to the high speed central intake hole 4 (4).
It is connected to a). Further, the flow path from the carburetor 11 (11a) to the high-speed central intake hole 4 (4a) is linear as shown, and the flow from the carburetor 11 (11a) to the high-speed side intake hole 3 (3a) is shown. The passages are inclined with respect to the straight flow passages as shown. The carburetor 12 is connected to the low-speed / high-speed intake pipe 9 (9a)
(9a) is inclined toward the high-speed intake pipe 8 (8a) as shown in the drawing so that the low-speed / high-speed intake hole 5 (5)
The low-speed / high-speed intake pipe 9 (9a) has an end portion (right end in FIG. 1) extending in the direction a) and the low-speed / high-speed intake hole 5 (5a).
Be communicated to.

The low-speed / high-speed intake pipe 9 (9a) and the high-speed intake pipe 8 (8a) are communicated with each other by a communication pipe 17 (17a) having a diameter smaller than that of the low-speed / high-speed intake pipe 9 (9a). . The portion communicated by the communication pipe 17 (17a) is outside the cylinder body 10, and the location where the end of the communication pipe 17 (17a) is connected to the high-speed intake pipe 8 (8a) is as shown in the figure. It is in the vicinity of the branching portion of the end portion (right end portion in FIG. 1) of the high speed intake pipe 8 (8a). Therefore, from the low-speed / high-speed intake pipe 9 (9a) to the communication pipe 17 (1
The intake air flowing through the high-speed intake pipe 8 (8a) through the connecting hole 21 (21a) and the high-speed central intake hole 4 (4)
It flows into the combustion chamber through a).

When the intake air is supplied only from the low-speed / high-speed intake pipe 9 (9a) (at the time of idling or low-speed operation), the air-fuel mixture generated in the carburetor 12 is the low-speed / high-speed intake pipe 9 (9a). Flow into the air, most of which is the low-speed / high-speed intake hole 5
(5a) flows into the combustion chamber, and the remaining portion of the air-fuel mixture is passed through the communication pipe 17 (17a) to the high-speed intake pipe 8 (8
a), then flows into the combustion chamber through the connection hole 21 (21a) and the high-speed central intake hole 4 (4a). (In this case, depending on the position of the branching portion of the high-speed intake pipe 8 (8a), the intake air that has flowed in through the communication pipe may also flow into the high-speed side intake hole 3 (3a), but 4 (4
It is advisable to allow it to flow through a) into the combustion chamber. ) As described above, most of the air-fuel mixture is the low-speed / high-speed intake hole 5 (5
The swirl is efficiently generated in the entire combustion chamber because the remaining air-fuel mixture flows into the combustion chamber through the high-speed central intake hole 4 (4a) by a weak flow and passes through a).

When the intake air is supplied from the low speed / high speed intake pipe 9 (9a) and the high speed intake pipe 8 (8a) (during medium speed operation or high speed operation), the air-fuel mixture generated in the carburetor 12 is The low-speed / high-speed intake pipe 9 (9a) flows into the combustion chamber through the low-speed / high-speed intake hole 5 (5a), and the vaporizer 11
The air-fuel mixture generated in (11a) is the high-speed intake pipe 8 (8a).
Through the high speed side intake holes 3 (3a) and the high speed central intake hole 4 (4a) into the combustion chamber. Since a large amount of air-fuel mixture can flow into the combustion chamber, it is possible to secure high charging efficiency and generate a required output.

[0013]

When the intake air is supplied only from the low-speed / high-speed intake pipe (during idling or low-speed operation), most of the intake air flows into the combustion chamber through the low-speed / high-speed intake hole by a strong flow. However, since the remaining part of the intake air flows into the combustion chamber from the communication hole through the high-speed intake pipe and the high-speed central intake hole by a weak flow, it flows from the three intake holes at the same time with a flow of approximately the same strength. As compared with the related art, swirls are efficiently generated without mutual collision of intake air in the combustion chamber. Moreover, since swirls are generated in the part near the center of the combustion chamber, and swirls are generated in the entire combustion chamber, ignition is ensured even when the spark plug is installed in the center part of the upper surface of the combustion chamber. And it will be easier. This is especially effective at the start.

When the intake air is supplied only from the low-speed / high-speed intake pipe (during idling or low-speed operation), a part of the intake air enters the high-speed intake pipe through the communication hole. There is no negative pressure in the pipe, and burned gas does not flow back from the intake hole to the high-speed intake pipe. Therefore, it is possible to prevent a decrease in combustion efficiency when shifting from low speed operation to high speed operation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a cross section of a part of an intake device for an internal combustion engine.

[Explanation of symbols]

 1,1a Cylinder 2,2a Combustion chamber 3,3a High speed side intake hole 4,4a High speed central intake hole 5,5a Low speed / high speed intake hole 6,6a, 7,7a Exhaust hole 8,8a High speed intake pipe 9,9a Low-speed / high-speed intake pipe 10 Cylinder body 11, 11a, 12, Vaporizer 13, 13a, 14, Piston valve 15, 15a, 16 Throttle valve 17, 17a Communication pipe 18, 18a, 19, 19a Exhaust pipe

Claims (1)

[Claims] 1. Three intake holes and two or more exhaust holes are arranged so as to face each other on the circumference of the combustion chamber, and one of the three intake holes is a low speed / high speed intake hole. In an internal combustion engine in which the remaining two intake holes are used as high speed intake holes, a low speed / high speed intake pipe connected to the low speed / high speed intake holes and a high speed intake air connected to the high speed intake holes An intake device for an internal combustion engine, characterized in that the pipe and the pipe communicate with each other.