JPH1077913A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain mixing with recirculating gas without disturbing the flow of intake gas so as to improve the characteristic of an internal combustion engine by jointing a connecting part of a recirculating gas passage to a main intake passage in an offset state from intake gas flowing in the main intake passage. SOLUTION: The center of a main intake passage 10 of a connection part and the center of a recirculating gas passage 16 are offset, that is, the layout direction of the recirculating gas passage 16 is shifted in the tangential direction of the main intake passage 10, so that recirculating gas flowing in the recirculating gas passage 16 can be mixed into the main intake passage 10 without disturbing the flow velocity of fresh air flowing in the main intake passage 10. The recirculating gas flowing in the recirculating gas passage 16 is blasted to the internal wall of the main intake passage 10 so as to flow in such a way as to whirl spirally around the fresh air flowing in the main intake passage 10, and the recirculating gas is uniformly mixed with the fresh air and fed to an intake manifold 14. Mixing with the recirculating gas is therefore attained without disturbing the flow of intake gas.

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 having an EGR mechanism for recirculating a part of exhaust gas for purifying exhaust gas together with fresh air taken from an air cleaner. It is about.

[0002]

2. Description of the Related Art As a conventional technique of this kind, there is known a technique disclosed in Japanese Utility Model Publication No. 5-17416, for example. In the intake manifold disclosed in this publication, a technique is disclosed in which fresh air taken in from an air cleaner and recirculation gas that is a part of exhaust gas are separately supplied.

[0003]

The flow of the intake gas in the intake manifold having a large volume is slower than the flow of the intake gas in the main intake passage having a small sectional area. The problem that it is difficult to mix uniformly and the ratio of the intake gas and the recirculation gas of the mixed gas of each cylinder are made equal to make the combustion of each cylinder of the internal combustion engine uniform,
There is a problem that it is difficult to achieve the target performance of the internal combustion engine.

[0004] It is a technical object of the present invention to solve the above problems and to provide an intake device for an internal combustion engine that can uniformly mix intake gas and recirculated gas.

[0005]

In order to solve the above problems,
The measures taken in claim 1 include a main intake passage communicating from the air cleaner to the intake manifold via a throttle valve, and a recirculation gas passage for mixing a predetermined amount of exhaust gas as recirculation gas into intake gas flowing through the main intake passage. In the intake device for an internal combustion engine, the connection of the recirculation gas passage to the main intake passage is offset and joined to the intake gas flowing through the main intake passage. By offsetting and joining the connection between the recirculation gas passage and the main intake passage, mixing with the recirculation gas is possible without obstructing the flow of the intake gas flowing through the main intake passage, maximizing the characteristics of the internal combustion engine. It can be withdrawn.

According to a second aspect of the present invention, the connecting portion of the recirculation gas passage to the main intake passage includes an annular portion extending along the outer periphery of the main intake passage, and a mixing passage communicating from the annular portion to the main intake passage. And the mixing passage intersects the flow direction of the main intake passage at an acute angle. With this configuration, by the flow of the intake gas flowing through the main intake passage, the reflux gas in the mixing passage is sucked into the main intake passage, and the mixture of the intake gas and the reflux gas can be made uniform.

[0007] The means taken in claim 3 is that the mixing passage is arranged on the entire outer periphery of the main intake passage. With this configuration, the recirculation gas is supplied from the entire outer periphery of the main intake passage, and the mixing accuracy of the intake gas and the recirculation gas can be improved.

The means taken in claim 4 is that a spiral passage in the flow direction of the main intake passage is formed at a connection portion of the recirculation gas passage to the main intake passage. With this configuration,
The recirculation gas is spirally swirled and mixed with the intake gas flowing through the main intake passage, so that the mixture of the intake gas and the recirculation gas can be made uniform.

The measures taken in claim 5 are that the connecting portion is formed between the throttle valve and the intake manifold in the main intake passage. With this configuration, the recirculated gas consisting of exhaust gas does not pass through the throttle valve, so that the throttle valve is not contaminated, and the intake gas and the recirculated gas can be mixed just before the large intake manifold. Can be homogenized.

[0010]

1 to 8 show an embodiment of the present invention.
This will be described with reference to the drawings shown in FIG.

FIG. 1 schematically shows an intake device of an internal combustion engine. Reference numeral 10 denotes a main intake passage communicating with an air cleaner (not shown), a throttle valve 12, and an intake manifold 14. In the present embodiment, the engine is a four-cylinder internal combustion engine, and four distribution pipes 15 communicate with each cylinder of the intake manifold 14. Inside the main intake passage 10, fresh air from the air cleaner flows in a direction indicated by an arrow in FIG. A recirculation gas passage 16 recirculates a part of the exhaust gas discharged by combustion of the internal combustion engine to the main intake passage 10 for purifying the exhaust gas. The recirculation gas flowing through the recirculation gas passage 16 is controlled by a valve 18 according to the operating state of the internal combustion engine. The region surrounded by the frame 20 indicates a connection portion of the recirculation gas passage 16 to the main intake passage 10. Therefore, the connection portion 20 of the main intake passage 10
Only fresh air from the air cleaner flows to the upstream side, and fresh air from the air cleaner flows to the downstream side.
The intake gas mixed with the reflux gas controlled by the above flows. Therefore, the recirculation gas does not flow into the throttle valve 12, and the operation of the throttle valve 12 is not affected even if the recirculation gas is contaminated by the combustion of the internal combustion engine.

FIG. 2 shows a first embodiment of the present invention, and FIG. 2 shows a cross section of the main intake passage 10 at the connecting portion 20. In the first embodiment, the position of the center of the main intake passage 10 and the position of the center of the recirculation gas passage 16 are offset. That is, the reflux gas passage 1
The direction in which the cooling gas 6 is arranged is shifted in the tangential direction of the main intake passage 10, and the recirculation gas flowing in the recirculation gas passage 16 is mixed into the main intake passage 10 without obstructing the flow velocity of the fresh air flowing in the main intake passage 10. You can do it.
Further, since the recirculated gas flowing through the recirculated gas passage 16 is blown to the inner wall of the main intake passage 10, the recirculated gas spirals around the fresh air flowing through the main intake passage 10 by a combined force with the flow of fresh air flowing through the main intake passage 10. The recirculated gas flows in a spiral shape, and is uniformly mixed with the fresh air.
Supplied to

FIGS. 3 and 4 show a second embodiment of the present invention. FIG. 3 shows a longitudinal section of the main intake passage 10 in the connecting portion 20. FIG. 4 is a schematic perspective view of the second embodiment. In the second embodiment, the recirculation gas passage 16 is connected to the main intake passage 10.
The recirculation gas flows into the main intake passage 10 through a mixing passage 24 which merges at an acute angle from the annular passage 22 without opposing the flow of the main intake passage 10 from the annular passage 22. It has become. Therefore, the recirculated gas in the mixing passage 24 can be sucked into the main intake passage 10 by the flow of fresh air in the main intake passage 10, and the intake gas and the recirculated gas are uniformly mixed by the suction effect. It is important that the annular passage 22 is formed in the entire outer periphery of the main intake passage 10, and may be integrated with the mixing passage 24 such as the passage width and the cross-sectional shape of the passage as shown in FIG. 5.

FIGS. 6 to 8 show a third embodiment of the present invention. 6 is a cross section of the main intake passage 10 at the connecting portion 20, FIG. 7 is a cross-sectional view taken along the line AA in FIG. 6 (a vertical cross section of the main intake passage 10 at the connecting portion 20), and FIG. ing. In the connecting portion 20 of the third embodiment, a spiral passage 26 is formed on the extension of the reflux gas passage 16. The spiral passage 26 is formed along the inner wall of the main intake passage 10 in the flow direction of the main intake passage 10, and the main intake passage 1 is provided downstream of the spiral passage 26.
An opening 28 that merges with zero is provided. Therefore, the recirculated gas is connected to the connecting portion 20 of the recirculated gas passage 16 to the main intake passage 10.
In this case, since the air is spirally swirled in the flow direction of the main intake passage 10 and flows out into the main intake passage 10, the intake manifold 14 can obtain a uniform mixture of the intake gas and the recirculated gas.

[0015]

According to the first aspect of the present invention, the main intake passage communicating from the air cleaner to the intake manifold via the throttle valve, and a predetermined amount of the exhaust gas is mixed with the intake gas flowing through the main intake passage as a recirculation gas. In the intake device for the internal combustion engine including the recirculation gas passage, the connection of the recirculation gas passage to the main intake passage is joined to the intake gas flowing through the main intake passage so as to be offset. By offsetting and joining the connecting portions, it is possible to mix with the recirculated gas without obstructing the flow of the intake gas flowing through the main intake passage, thereby maximizing the characteristics of the internal combustion engine.

According to the second aspect of the present invention, the connecting portion of the recirculation gas passage to the main intake passage has an annular portion along the outer periphery of the main intake passage, and a mixing passage communicating from the annular portion to the main intake passage. Since the mixing passage intersects at an acute angle with respect to the flow direction of the main intake passage, the recirculation gas of the mixing passage is sucked into the main intake passage by the flow of the intake gas flowing through the main intake passage, and the intake gas is mixed with the intake gas. The mixing of the reflux gas can be made uniform.

According to the third aspect of the present invention, since the mixing passage is arranged on the entire outer periphery of the main intake passage, the recirculation gas is supplied from the entire outer periphery of the main intake passage to improve the mixing accuracy of the intake gas and the recirculation gas. Can be.

According to the fourth aspect of the present invention, since the spiral passage in the flow direction of the main intake passage is formed at the connection portion of the recirculation gas passage to the main intake passage, the recirculation gas flows into the intake gas flowing through the main intake passage. The gas is spirally swirled with respect to and mixed, and the mixing of the intake gas and the recirculated gas can be made uniform.

According to the fifth aspect of the present invention, since the connection portion is formed between the throttle valve and the intake manifold in the main intake passage, the recirculated gas composed of exhaust gas does not pass through the throttle valve, so that the throttle valve is provided. The intake gas and the recirculation gas can be mixed just before the large intake manifold without polluting the valve, and the mixing can be made uniform.

[Brief description of the drawings]

FIG. 1 is a schematic view of an intake device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a connection portion between a recirculation gas passage and a main intake passage according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a connection portion between a recirculation gas passage and a main intake passage according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a connection portion between a recirculation gas passage and a main intake passage according to a second embodiment.

FIG. 5 is a cross-sectional view corresponding to FIG. 3, showing a modification of the second embodiment of the present invention.

FIG. 6 is a sectional view of a connection portion between a recirculation gas passage and a main intake passage according to a third embodiment of the present invention.

FIG. 7 is a sectional view taken along the line AA in FIG. 6;

FIG. 8 is a perspective view of a connection portion between a recirculation gas passage and a main intake passage according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Main intake passage 12 ... Throttle valve 14 ... Intake manifold 16 ... Reflux gas passage 20 ... Connection part 22 ... Annular passage 24 ... Mixing passage 26 ... Spiral passage

Claims (5)

[Claims] 1. A main intake passage communicating from an air cleaner to an intake manifold via a throttle valve,
A recirculation gas passage that mixes a predetermined amount of exhaust gas as recirculation gas into intake gas flowing through the main intake passage, wherein a connection portion of the recirculation gas passage to the main intake passage is connected to the main intake passage. An intake device for an internal combustion engine, which is joined to an intake gas flowing through a passage while being offset. 2. A connecting portion of the recirculation gas passage to the main intake passage, an annular portion along an outer periphery of the main intake passage,
2. The intake device for an internal combustion engine according to claim 1, further comprising a mixing passage communicating from the annular portion to the main intake passage, wherein the mixing passage intersects at an acute angle with respect to a flow direction of the main intake passage. 3. The intake device for an internal combustion engine according to claim 2, wherein the mixing passage is arranged on the entire outer periphery of the main intake passage. 4. The intake device for an internal combustion engine according to claim 1, wherein a spiral passage in a flow direction of the main intake passage is formed at a connection portion of the recirculation gas passage to the main intake passage. 5. The intake device for an internal combustion engine according to claim 1, wherein the connection portion is formed between a throttle valve of the main intake passage and an intake manifold. .