JPS5846668B2 - Internal combustion engine intake passage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an intake passage of a multi-cylinder internal combustion engine, which is provided with an intake balance communication passage that communicates between each intake passage.

In multi-cylinder internal combustion engines that have multiple independent intake throttle valves, each intake passage has traditionally been communicated with each other in order to balance the variation in intake air amount between each cylinder due to variation in the opening degree of each throttle valve. A communication passage for intake balance is provided.

Conventional intake balance communicating passages have a structure in which they open in the vicinity of the throttle valve of each intake passage in a direction substantially perpendicular to the axis of the intake passage.

For this reason, although it is possible to balance the intake air between each intake passage, it has not been possible to actively improve the combustion efficiency within each cylinder.

In addition, when performing exhaust gas recirculation (EGR) from the exhaust passage to the intake passage using the intake balance communication passage, impurities in the exhaust may contaminate the throttle valve, and furthermore, the impurities may be deposited near the throttle valve. This also has the disadvantage that the intake passage opening area changes especially during idling, causing problems in engine operation.

The present invention provides a structure of an intake passage for an internal combustion engine that can improve the combustion state in each cylinder by actively generating a vortex flow in each cylinder by intake air, and can eliminate the above-mentioned drawbacks.

The intake passage of an internal combustion engine according to the present invention is an intake passage of a multi-cylinder internal combustion engine having a plurality of throttle valves provided in each of the plurality of intake passages, and an intake passage for communicating between each intake passage is provided, The communication passage is opened to the intake passage between the throttle valve and the intake valve, and each opening end portion of the communication passage adjacent to the opening to each intake passage is directed in a direction from the intake upstream side to the intake downstream side of the intake passage. It is characterized in that it is provided in a direction that intersects with the other two at an acute angle.

Since the end portion of the opening intersects the intake passage at an acute angle, the intake air from the intake balance communication passage can be guided forcefully to each cylinder through the intake valve, and therefore, the intake air can be actively drawn into each cylinder. Combustion conditions can be improved by creating a laminar vortex flow.

In this case, a carburetor having a throttle valve is attached to the internal combustion engine via an intake manifold, and the intake balance communication passage is opened in the intake passage of the intake manifold, and the distance between the throttle valve and the opening is It can also be constructed so that it can be made relatively large.

Furthermore, if an exhaust gas recirculation path is connected to the intake balance communication path and the exhaust gas is recirculated from the exhaust path to the intake path through the communication path, the exhaust gas can be recirculated with a simple structure with a small number of parts. An intake passage that allows circulation and prevents impurities from adhering to the vicinity of the throttle valve can be obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 and 2 show an internal combustion engine 1 having four cylinders 12.
2 is a diagram showing the main parts when the intake passage of the present invention is provided in the engine 0, each cylinder is composed of an internal combustion engine main body having a cylinder 14, a piston 16, a cylinder head 18, etc., and each main body has an intake manifold 20. via vaporizer 22
is attached to form a plurality (four) of intake passages 24.

An intake throttle valve 26 is provided in each intake passage, and the amount of intake air is adjusted by opening and closing these throttle valves.

In the illustrated embodiment, one carburetor or throttle valve is disposed in each cylinder, and each cylinder has an independent intake passage.

The air-fuel mixture from each intake passage passes through the intake valve 28 into the combustion chamber 3.
After the explosion, the exhaust gas is sent out to the exhaust passage 34 through the exhaust valve 32.

An intake balance communication passage 36 is provided above the intake manifold 20 to communicate the intake passages with each other.

In the illustrated example, the communication passage 36 has a conduit member 38 fastened to the intake manifold and a communication passage portion 40 formed within the intake manifold, and has an opening 42 to each intake passage within the intake manifold. .

Each end portion 40A of the communication passage 36 adjacent to the opening 42 is formed in a direction that intersects the direction from the intake upstream side to the intake downstream side (arrow X in FIG. 2) at an acute angle (approximately 30 degrees).

Further, the opening 42 is located between the throttle valve 26 and the intake valve 28.

Therefore, the intake air from the intake balance communication passage 36 is forcefully introduced into each cylinder 12 through the intake valve 28, and a laminar vortex of intake air is generated within each cylinder.

Therefore, the combustion state within each cylinder can be greatly improved by the vortex flow.

Further, the position of the opening is preferably selected at a downstream position relatively distant from the throttle valve 26. By doing so, the exhaust recirculation passage 44 is connected to the communication passage 36, and the exhaust gas recirculation passage 44 is connected to the communication passage 36, and the exhaust gas recirculation passage 44 is connected to the communication passage 36. Even when exhaust gas is recirculated from 34 to the intake passage 24, impurities in the exhaust gas can be prevented from adhering to the vicinity of the throttle valve 26.

Furthermore, by configuring the air-fuel mixture for starting warm-up to be introduced into the intake balance communication passage 36 and supplied to the internal combustion engine through the opening 42, the intake balance communication passage can be used as a starter.

Since the intake passage of the internal combustion engine according to the present invention has the configuration described above, the following effects can be achieved.

Since the portion of the intake balance communication passage adjacent to the opening to each intake passage, that is, the terminal portion of the communication passage, is provided in a direction that forms an acute angle and crosses the direction from upstream to downstream of the intake passage, balance intake air can be achieved. is introduced vigorously through the intake valves to actively create a laminar vortex of intake air within each cylinder, improving the combustion conditions within the cylinders.

Furthermore, as a result of the improvement in the combustion state, the required advance angle of the ignition timing becomes retarded and combustion variations at light loads are reduced, making it easier to maintain a smooth operating state of the internal combustion engine.

In this case, the opening 42 of the intake balance communication passage is connected to the throttle valve 2.
It is preferable to provide the intake valve 28 at a position spaced apart from the intake valve 6 and closer to the intake valve 28.

Furthermore, if the internal combustion engine is equipped with an exhaust gas recirculation device, the structure can be improved by connecting the exhaust gas recirculation path to the intake balance communication path and recirculating the exhaust gas from each opening 42 to the intake path 24. This can be simplified, and the drawback that impurities in the exhaust gas adhere to the vicinity of the throttle valve 26 can be prevented.

Therefore, the throttle valve opening area during idling can be maintained constant, and changes over time in the air-fuel ratio during idling can also be eliminated.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view taken along the line I-I in Fig. 2 between internal combustion engines having an intake passage of the present invention, and Fig. 2 is viewed from the arrow line I-I in Fig. 1, with some parts omitted FIG. 2 is a partially cross-sectional plan view showing essential parts. In each figure, the same reference numbers indicate the same parts, 10...multi-cylinder internal combustion engine, 20...
... Intake manifold, 22 ... Carburetor, 24 ... Intake passage, 26 ... Throttle valve, 2
8...Intake valve, 36...Intake balance communication passage, 40A...Terminal portion of communication passage, 42
...Opening, 44...Exhaust recirculation path,
...Indicates the direction of intake flow.

Claims (1)

[Scope of Claims] 1. In an intake passage of a multi-cylinder internal combustion engine having a plurality of throttle valves provided in each of the plurality of intake passages, an intake balance connection for communicating between the intake passages downstream of the throttle valve is provided. A passage is provided, the communication passage is opened to the intake passage between the throttle valve and the intake valve, and a terminal portion of the communication passage adjacent to the opening to each intake passage is directed from upstream to downstream of the intake passage. An intake passage for an internal combustion engine, characterized in that it is provided in a direction that intersects with the other one at an acute angle. 2. In the intake passage according to claim 1, a carburetor having a throttle valve is installed in an internal combustion engine through an intake manifold, and the intake balance communication passage is opened in the intake passage of the intake manifold. An intake passage for an internal combustion engine characterized by: 3. In the intake passage according to claim 1 or 2, an exhaust gas recirculation passage is connected to the intake balance communication passage, and exhaust gas is recirculated from the exhaust passage to the intake passage via the communication passage. An intake passage of an internal combustion engine characterized by obtaining.