JPH07145769A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To suppress deterioration in transient response or increase of HC in exhaust gas while retaining swirl force. CONSTITUTION:A fuel injection valve 106 is disposed along central axis of a cylinder of an intake pipe 106 for supplying intake to a Siamese intake port comprising a straight port 102 and a helical port 103, and a partition wall 108 is disposed in deviation from the central axis, extending upstream of injection of the fuel injection valve 10. A swirl valve 111 for opening/closing a straight flow path 109 is disposed upstream of the fuel injection valve. At the time of light load, the work valve 111 is closed, so that a mixture is supplied via a helical flow path 110 and the helical port 103, resulting in a swirl. Due to this swirl, a rich, mixture supplied from the straight port 102 moves to the vicinity of an ignition plug 101, so that the ignition is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an internal combustion engine, and more particularly to an intake system for an internal combustion engine capable of generating a powerful swirl.

[0002]

2. Description of the Related Art It is known to provide a so-called helical port to generate swirl in a combustion chamber in order to improve the combustion efficiency in the combustion chamber when the internal combustion engine is under a light load. Furthermore, in an internal combustion engine equipped with a helical port, in order to maintain ignitability even in the case of lean burn, a mechanism for stratifying the mixture to supply a rich mixture to the vicinity of the spark plug was provided. An intake system for an internal combustion engine has also been proposed (see Japanese Utility Model Laid-Open No. 4-21761).

The intake system for an internal combustion engine according to the above proposal is
A communication hole is opened in a partition wall provided at the center of the intake passage, a fuel injection valve is installed upstream of the communication hole, and a projection protruding on the straight port side of the partition wall is provided. With the above structure, part of the intake air flowing on the straight port side is guided to the helical port side through the communication hole, so that it is possible to supply the rich air-fuel mixture near the spark plug and to strengthen the swirl force.

[0004]

However, in the intake system for an internal combustion engine according to the above-mentioned proposal, since the partition wall and the fuel injection valve are arranged coaxially and the projection is provided on the straight port side, the partition wall is provided. And fuel tends to adhere to the protrusions, which deteriorates the transient response or HC in the exhaust gas.
Unavoidable increase of.

The present invention has been made in view of the above problems, and provides an intake system for an internal combustion engine capable of suppressing deterioration of transient response or increase of HC in exhaust gas while maintaining swirl force. The purpose is to do.

[0006]

An intake system for an internal combustion engine according to the present invention comprises a Siamese intake port composed of two intake ports, a straight port and a helical port, and one Siamese intake port connected to the Siamese intake port. An intake pipe, a fuel injection valve for injecting fuel to the Siamese intake port, which is installed on the approximate center axis of the combustion chamber in the intake pipe, and a fuel injection valve installed in the intake pipe, offset to one side from the central axis of the combustion chamber A partition wall that extends upstream from the spray range of fuel injected from the valve and divides the intake pipe into a straight flow path including the fuel injection valve and a helical flow path that does not include the fuel injection valve, and is disposed upstream of the fuel injection valve. And a swirl control valve that opens and closes the straight flow path.

[0007]

In the intake system for the internal combustion engine according to the present invention, the swirl control valve is closed at the time of a light load, and intake is mainly performed from the swirl port, so that a strong swirl is generated and at the same time, from the fuel injection valve. Since the injected fuel flows into the cylinder almost evenly through the swirl port and the straight port, rich fuel is supplied near the spark plug.

Since the partition wall that divides the straight flow passage and the helical flow passage does not extend to the fuel spray range of the fuel injection valve, no fuel adheres.

[0009]

FIG. 1 is a top view of a cylinder equipped with an intake system for an internal combustion engine according to the present invention. On the top surface of the cylinder 100, a spark plug 101, a straight intake port 102, a helical intake port 103, and two Exhaust port 104 and 1
05 is arranged. The straight intake port 102 and the helical intake port 103 constitute a so-called Siamese intake port, and one intake pipe 10 is divided into two in the vicinity of the intake port but is not divided upstream.
The intake air is supplied to the two intake ports by 6.

A fuel injection valve 1 for injecting fuel into the intake pipe 106 is provided on the intake pipe 106 substantially on the central axis of the cylinder 100.
07 is installed. The fuel injection valve 107 injects fuel in a fan shape with an angle θ toward the straight intake port 102 and the helical intake port 103. The fuel injection valve 10
7 on the substantially central axis of the cylinder 100, the straight intake port 102 and the helical intake port 103
From the above, the fuel is supplied into the cylinder 100 almost evenly.

In the intake pipe 106, there is provided a partition wall 108 which is located at one side of the center axis of the cylinder 100 and extends upstream of the fuel injection range of the fuel injection valve 107.
06 is divided into a straight flow passage 109 including the fuel injection valve 106 and a helical flow passage 110 not including the fuel injection valve 106. Further, the fuel injection valve 10 of the straight passage 109
A swirl valve 111 for opening and closing the straight passage 109 is installed upstream of 7.

FIG. 2 is an explanatory view of operating conditions during light load operation, in which the straight flow path 10 is controlled by the swirl valve 111.
Since 9 is closed, intake air to the cylinder 100 is performed via the helical flow path 110 and the helical port 103. Therefore, a swirl occurs in the cylinder 100 as indicated by arrow A. The fuel injected from the fuel injection valve 107 is straight intake port 102 and helical intake port 10.
Since the air enters into the cylinder almost uniformly from 3, the air-fuel mixture supplied from the straight intake port 102 becomes rich and the air-fuel mixture supplied from the helical intake port 103 becomes lean.

The rich air-fuel mixture 112 supplied from the straight intake port 102 is supplied to the helical port 10
The swirl of the lean air-fuel mixture supplied from 3 moves in the direction of arrow B, that is, in the direction of the spark plug 101 of the cylinder 100. Therefore, even when the load is light, the surroundings of the spark plug 101 are covered with the rich air-fuel mixture, so that the ignitability can be secured.

A masking 113 may be provided in the cylinder 100 in order to make the movement of the rich air-fuel mixture more efficient. FIG. 3 is an explanatory diagram of the operating condition during high load operation, in which the swirl valve 111 is opened. Therefore, the straight intake port 102 and the helical intake port 103
A mixture of intake air and fuel is evenly supplied to secure good ignition and combustion.

FIG. 4 is a sectional view taken along the line AA of the second embodiment. Instead of providing the partition wall 108, the helical flow path may have a substantially trapezoidal shape or a triangular shape. That is, when the swirl valve is closed, a large amount of intake air flows outside the helical flow path, so swirl occurs in the cylinder 100.

[0016]

According to the intake system for an internal combustion engine according to the present invention, since the partition wall is biased with respect to the center of the cylinder, it is possible to generate a powerful swirl without fuel adhering to the wall surface at light load. In addition to the above, the rich air-fuel mixture supplied from the straight port can be moved to the vicinity of the spark plug to maintain the ignitability.

[Brief description of drawings]

FIG. 1 is a top view of a cylinder equipped with an intake device for an internal combustion engine according to the present invention.

FIG. 2 is an explanatory diagram of operating conditions during light load operation.

FIG. 3 is an explanatory diagram of an operating condition during high load operation.

FIG. 4 is a sectional view taken along line AA of the second embodiment.

[Explanation of symbols]

 100 ... Cylinder 101 ... Spark plug 102 ... Straight port 103 ... Helical port 104, 105 ... Exhaust port 106 ... Intake pipe 107 ... Fuel injection valve 108 ... Partition wall 109 ... Straight flow passage 110 ... Helical flow passage 111 ... Swirl valve 112 ... Rich Mixture 113 ... Masking

Claims (1)

[Claims] 1. A Siamese intake port composed of two intake ports, a straight port and a helical port, an intake pipe connected to the Siamese intake port, and a substantially central axis of a combustion chamber in the intake pipe. A fuel injection valve installed above for injecting fuel into the Siamese intake port; and a spray range of fuel injected from the fuel injection valve, which is installed in the intake pipe offset from the central axis of the combustion chamber to one side. A partition wall that extends further upstream and divides the intake pipe into a straight flow path that includes the fuel injection valve and a helical flow path that does not include the fuel injection valve; An intake device for an internal combustion engine, comprising: a swirl control valve that opens and closes a passage.