JPH07279801A - Fuel supply system for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a thick air-fuel mixture state near an ignition plug in an internal combustion engine of two-intake valve system. CONSTITUTION:A fuel injection valve 8 is arranged between a pair of intake ports 6a, 6b, first communicating holes 11a, 11b opened into intake ports 6a, 6b on both the sides are formed near its injection hole 9, a communicating passage 10 extending form the injection port 9 of the fuel injection valve 8 to the vicinity of valve ports 5a, 5b is formed between the intake ports 6a, 6b, and second communicating holes 12a, 12b opened into the intake ports 6a, 6b on both the sides are formed from the top end of the communicating hole 10. A fuel is carried by a part of the intake flow running flowing from the first communicating holes 11a, 11b into the communicating passage 10, and supplied to the intake ports 6a, 6b on both the sides near the valve ports 5a, 5b through the second communicating holes 12a, 12b, and a thick air-fuel mixture state is provided near an ignition plug 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for an internal combustion engine, and more particularly to a fuel supply system suitable for lean burn operation in an intake two-valve internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an intake two-valve internal combustion engine in which a pair of intake ports are formed in parallel, a fuel injection valve is arranged between the intake ports, and communication is formed near the injection port of the fuel injection valve. A fuel supply device is known in which fuel is injected and supplied into the intake ports on both sides through a mouth.

Referring to FIG. 4, a combustion chamber 21 is provided with a spark plug 22 at a central position of its ceiling surface, and a pair of intake plugs (not shown) are opened and closed on one side thereof. Valve openings 23 are formed, and a pair of intake ports 24 communicating with the valve openings 23 are arranged in parallel. A fuel injection valve 25 is arranged between the intake ports 24, 24, and the fuel injected from a pair of injection ports 25a of the fuel injection valve 25 is supplied from the injection port 25a portion so as to be supplied to the intake ports 24 on both sides. A communication port 26 is formed toward the intake ports 24 on both sides.

In Japanese Utility Model Laid-Open No. 3-129726, an intake three-valve internal combustion engine in which three intake ports are arranged in parallel is designed to inject fuel toward the central intake port. Is disclosed.

[0005]

In order to perform the lean burn operation, it is desirable that the air-fuel mixture in the vicinity of the ignition plug 22 is rich. However, in the above arrangement, it is directed toward the intake port 24 at a position away from the valve port 23. Since the fuel is injected in the direction away from the spark plug 22, the air-fuel mixture tends to be lean in the vicinity of the spark plug 22, which is disadvantageous in establishing lean combustion.

Therefore, it is conceivable to dispose the fuel injection valve 25 as close to the valve opening 23 as possible, but this is not possible because it is structurally unreasonable.

On the other hand, in the intake three-valve internal combustion engine disclosed in the above publication, since the fuel is injected toward the central intake port, a rich air-fuel mixture is produced near the spark plug, but three intake ports are used. Since it is necessary to form three intake valves and to form them, there is a problem that the cost becomes high.

In view of such conventional problems, it is an object of the present invention to provide a fuel supply system for an internal combustion engine of the intake two-valve system which can obtain a rich air-fuel mixture near the spark plug. .

[0009]

SUMMARY OF THE INVENTION The present invention is directed to an internal combustion engine of a two-valve intake system in which a pair of intake ports are formed in parallel and a fuel injection valve is arranged between the intake ports. A first communication port that opens in the intake ports on both sides is formed in the vicinity, and a communication passage that extends from the injection port of the fuel injection valve to a position near the valve port of the intake port is formed between the intake ports, and the tip of this communication passage is formed. From the second to open in the intake ports on both sides
It is characterized in that a communication port of is formed.

[0010]

According to the present invention, when the fuel is injected from the fuel injection valve toward the communication passage, the fuel is continuously communicated with a part of the intake flow that has flowed into the passage from the intake ports on both sides through the first communication port. It flows toward the tip of the passage, and the second from the tip of the communication passage.
Since it is supplied to the intake ports on both sides near the valve port through the communication port, a rich mixture state can be obtained near the spark plug, which is advantageous for lean burn operation. When the first communication port is not provided, the injected fuel adheres to the wall surface of the communication passage, and the fuel is smoothly supplied from the second communication port to the intake port with good controllability at a predetermined timing. Although not provided, by providing the first communication port, it is possible to appropriately supply fuel by the intake air flow passing through the communication passage as described above. Alternatively, a fuel injection valve having three injection ports may be used to supply a part of the fuel directly to the intake port through the first communication port.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

Reference numeral 1 is a cylinder block of an internal combustion engine, 2 is a cylinder head, 3 is a cylinder formed in the cylinder block 1, and 4 is a combustion chamber formed on a cylinder 3 below the cylinder head 2. A pair of intake valve ports 5a and 5b are opened on one side of the ceiling surface of the combustion chamber 4 and are opened and closed at predetermined timings by intake valves (not shown).
Moreover, a pair of intake ports 6a and 6b are formed in parallel in the cylinder head 2 so as to communicate with the valve ports 5a and 5b. A spark plug 7 is arranged at the center of the ceiling surface of the combustion chamber 4. Although not shown, a pair of exhaust valve ports are opened on the other side of the ceiling surface of the combustion chamber 4, and each exhaust valve opens and closes at a predetermined timing, and each exhaust port has an exhaust port. Are in communication.

A pair of intake ports 6 of the cylinder head 2.
A fuel injection valve 8 is disposed between a and 6b, and its injection port 9
First opening in the intake ports 6a, 6b on both sides in the vicinity of the
Communication ports 11a and 11b are formed. Further, a communication passage 10 is formed between the intake ports 6a and 6b so as to reach from the injection port 9 of the fuel injection valve 8 to a position near the valve ports 5a and 5b of the intake ports 6a and 6b. Second communication port 12 opening in the ports 6a, 6b
a and 12b are formed.

In the above structure, fuel is injected from the fuel injection valve 8 toward the communication passage 10 during the intake stroke of the internal combustion engine, and a part of the intake flow flowing through the intake ports 6a and 6b is in the first communication. Communication passage 10 through the openings 11a and 11b
The fuel injected from the injection port 9 flows toward the tip of the communication passage 10 without adhering to a part of the intake flow flowing toward the tip of the communication passage 10 and adhering to the wall surface of the communication passage 10. The fuel is supplied from the tip of the communication passage 10 to the intake flow flowing through the second communication ports 12a and 12b and near the valve ports 5a and 5b in the intake ports 6a and 6b on both sides. As described above, since the fuel is supplied to the intake flow flowing in the intake ports 6a and 6b from between the intake ports 6a and 6b near the valve ports 5a and 5b, the spark plug located at the center of the combustion chamber 4 is provided. A rich mixture is formed near 7. Thus, the spark plug 7 can be used even during lean burn operation.
Since a rich air-fuel mixture state can be formed in the vicinity of, it is possible to reliably ignite and burn, and to secure a stable combustion state.

In the above embodiment, the fuel injection valve 9 injects the fuel only toward the communication passage 10. However, as in the embodiment shown in FIG. 3, the injection ports 13a are provided on both sides of the injection port 9. ,
The fuel injection valve 8 having 13b is used, and the intake ports 6a and 6b are passed from the second communication ports 12a and 12b through the communication passage 10.
Fuel to the first communication port 11a, 11
It is also possible to directly supply the fuel from b to the intake ports 6a and 6b on both sides. In this case, the first communication port 11a,
It is preferable that the amount of fuel supplied from 11b to the intake ports 6a, 6b be about one fifth or less of the total amount.

[0016]

According to the fuel supply system for an internal combustion engine of the present invention, when fuel is injected from the fuel injection valve toward the communication passage as described above, the fuel flows from the intake ports on both sides to the first communication port. It flows toward the tip of the passage together with a part of the intake air flowing into the communicating passage, and is supplied from the tip of the passage to the intake ports on both sides near the valve opening through the second communicating opening. It is possible to obtain a rich air-fuel mixture in the vicinity of, and it is only necessary to process the communication passage and the second communication port compared with the conventional configuration, so it is advantageous in lean burn operation with a simple configuration at low cost. It is possible to provide an excellent fuel supply device.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of an embodiment of a fuel supply device for an internal combustion engine of the present invention.

FIG. 2 is a vertical sectional front view of the embodiment.

FIG. 3 is a sectional plan view of another embodiment of the present invention.

FIG. 4 is a cross-sectional bottom view of a conventional fuel supply device for an internal combustion engine.

[Explanation of symbols]

 5a Valve opening 5b Valve opening 6a Intake port 6b Intake port 7 Spark plug 8 Fuel injection valve 9 Injection port 10 Communication path 11a 1st communication port 11b 1st communication port 12a 2nd communication port 12b 2nd communication port

Claims (1)

[Claims] 1. In a two-intake intake type internal combustion engine in which a pair of intake ports are formed in parallel, and a fuel injection valve is arranged between the intake ports, in an intake port on both sides near an injection port of the fuel injection valve. A first communication port that opens is formed, and a communication passage that extends from the injection port of the fuel injection valve to a position in the vicinity of the valve port of the intake port is formed between the intake ports, and the ends of the communication passage open into the intake ports on both sides. A fuel supply device for an internal combustion engine, characterized in that a second communication port is formed.