JPS6319550Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an intake system for an internal combustion engine capable of variable swirl generation, which is often used in direct injection diesel engines.

Direct-injection diesel engines are often configured to use the suction swirl (hereinafter simply referred to as swirl) when air is drawn into the combustion chamber to generate a mixture in a short time and accelerate the combustion rate. . However, the method of generating a swirl, which involves narrowing the cross section of the intake port's flow path in front of the intake port to increase the flow velocity of the intake air, also creates flow resistance to the intake air, reducing the intake efficiency of the combustion chamber. It will lower it. Therefore, during high-load operation, the means for generating swirl causes a reduction in output. To solve this problem, during low-load operation, we measure swirl generation and accelerate the combustion rate to obtain the appropriate output, while at high-speed operation, we suppress swirl generation and reduce flow resistance to intake air, making it possible to increase output. Swirl generating means are known. For example, as shown in Fig. 1, the intake air reaching the intake port 1 of each cylinder is controlled by butterfly valves (hereinafter simply referred to as butterfly valves) 4 installed in the flow paths 3 of the intake ports 2. be. A link 5 is attached to each butterfly valve 4, and by operating this link 5, all butterfly valves 4 are operated simultaneously. The butterfly valve 4 operates during low-load operation, narrows the cross section of the flow path 3 (see FIG. 2), and gives directionality to the intake air. Thereby, the intake air flowing into the combustion chamber 6 acts to effectively generate a swirl. Furthermore, during high-load operation, the Bata valves are aligned in the flow direction so that the Bata valves 4 do not provide flow resistance to the intake air in the flow path 3, and the cross-sectional area of the flow path 3 is kept as large as possible to increase suction efficiency. , measure the output increase. However, in a multi-cylinder diesel engine using such a conventional variable swirl generating means, the control of the butterfly valve 4 of each intake port must be linked using a link 5, etc., and the moving parts are dispersed in many locations. The structure is complex. Moreover, as shown in Fig. 3, the intake air flowing through each intake port 2 instantaneously pulsates at a high flow velocity V, which causes the butterfly valve 4 to vibrate, resulting in low reliability and durability. There are drawbacks.

The object of this invention is to provide an intake system for an internal combustion engine that can generate variable swirl.

The intake device for an internal combustion engine according to this invention includes a main passage formed in an intake manifold of the internal combustion engine, and an intake port that communicates with the main passage and supplies intake air in a predetermined inflow direction to the combustion chamber of the internal combustion engine. a side main path, a divided sub-path formed in the manifold in parallel with the main path, and an intake port side sub-path connected to the divided sub-path and formed in parallel with the intake port side main path. and an opening side end formed in parallel on the same plane on the upstream side of each of the divided secondary passages communicating with each combustion chamber of a plurality of cylinders of the internal combustion engine, and an inflow into each of these opening side ends. It is equipped with a single on-off valve that simultaneously controls the intake air amount and seals each of the opening side ends in the closed and closed states. By doing so, it is possible to also supply intake air from the divided sub-path.

Therefore, the intake system for an internal combustion engine according to this invention exhibits the following effects. That is, the intake air flowing through the opening of the intake manifold is always supplied to the intake port of each cylinder via the main path and the main path on the intake port side communicating with the main path. On the other hand, when a single opening/closing valve is operated, the intake air flowing into the sub-channels corresponding to the number of cylinders in the intake manifold from the opening side ends arranged in parallel on the same plane at the same position is as follows:
It is additionally supplied to the intake port of each cylinder via each divided sub-path and each intake port-side sub-path connected thereto.
For this reason, even in a multi-cylinder internal combustion engine, a sub-path among the flow paths that supply intake air to each intake port is opened and closed at one location by the operation of a single on-off valve, and the intake air to the intake ports is opened and closed. The inflow mode can be controlled,
In particular, the structure of the opening valve can be simplified, the number of parts can be reduced, and the cost can be reduced. Moreover, since each opening side end is directly opened and closed by the on-off valve, there is no communication between the divided sub-paths, and furthermore, when the opening side end of each divided sub-path is in the fully closed state, the opening side end of each divided sub-path is , are each sealed, so airtightness is excellent when the side road side is closed, and swirl can be strengthened at low output.

This invention will be explained below with reference to the accompanying drawings.

FIG. 4 shows an intake system (hereinafter simply referred to as an intake system) 7 for an internal combustion engine as an embodiment of this invention. This intake device 7 is a direct injection diesel engine (not shown) (shown as a three-cylinder engine).
The cylinder head 8 and the intake manifold 9 connected thereto. The intake manifold 9 has an opening 10 formed at one end, into which intake air from an air cleaner (not shown) flows. Immediately inside this opening 10, a main passage 12 and three divided sub-passages 13 are formed so as to divide the intake air that has passed through the opening and guide it to each combustion chamber 11, respectively. That is, on the lower side of the intake manifold 9, there is a main passage 12 through which intake air always flows toward the intake ports 14 of each combustion chamber 11, and on the upper side, there is a main passage 12 through which intake air flows additionally into the intake ports 14 only at a set time. , three divided sub-routes 1 arranged in parallel with each other
3 is formed. Among these, the opening-side ends 15 of the three divided sub-paths 13 facing the opening 10 are arranged side by side on the same plane, and these are simultaneously opened and closed at the same position by the butterfly valves 16 as opening/closing valves. on the other hand,
The main path 12 has an end opposite to the opening 10 in constant communication with the opening 10, and
As shown in the figure, the cross-sectional area of the main passage is gradually narrowed in the longitudinal direction, and the main passage is formed so that the amount of intake air supplied to each combustion chamber 11 is equal. Cylinder head 8
The three side intake ports 14 have respective flow paths divided into upper and lower portions by a threshold wall 21 (see FIG. 10). These upstream and downstream channels become one near the intake port 17, and the intake valve 1 opens and closes the intake port 17.
8, the intake port 14 side and the combustion chamber 11
It communicates with the side. Each main passage 19 on the lower side of the intake port 14 communicates with the main passage 12 on the intake manifold side, and each sub passage 20 on the upper layer communicates with each divided sub passage 13 on the intake manifold side. For this reason, the bata valve 16
The opening-side ends 15 of the divided sub-paths that are opened and closed are individually communicated with the suction ports 17 of the respective intake ports, and the divided sub-paths 13 do not communicate with each other. Furthermore, the main passage 19 on the intake port side is designed to increase the flow velocity of intake air relative to the intake port 17 on the downstream side.
Its cross-sectional area is gradually narrowed (see FIG. 10), and it is formed so that intake air is supplied to the combustion chamber 11 through the intake port 17 in a predetermined inflow direction. Bataben 1
6 is pivotally connected to the intake manifold 9 via a support shaft 22 that is integrated therewith. One end of this support shaft 22 protrudes outside the intake manifold 9, and an operating arm 23 is attached to it.
is fixed. A swirl control section 24 is connected to this operating arm 23 . This swirl control unit 24 uses a diaphragm (not shown) that operates in response to intake pressure, and when the negative pressure as intake pressure is large, that is,
The opening side end 15 of each divided secondary passage is closed during low load operation, and the opening side end 15 is opened during high load operation. Note that the swirl control section 24 may operate the butterfly valve 16 using other well-known means.

The operation of the intake device 7 shown in FIG. 4 will be explained.
First, when the swirl control unit 24 detects low-load operation, the butterfly valve 16 maintains the home position of the three opening side ends 15 of the divided sub-paths closed (see FIG. 8). As a result, all the intake air flowing in through the opening 10 is directed toward the main passage 12 and is supplied to the intake port 17 via each intake port side main passage 19.
In this case, the flow velocity of the intake air is increased by the main passage 19 on the intake port side, and the intake air flows into the combustion chamber 11 from the intake port 17 in a predetermined inflow direction, so that a strong swirl S can be generated. Note that each divided sub-path 13 side has its opening side end 15 closed, and the opening 10
From the side or from other divided sub-roads 13
Airtightness is maintained to prevent intake of air from the sides.

On the other hand, when the swirl control unit 24 detects high-load operation, the butterfly valve 16 rotates 90 degrees from the closed position (home position) of the divided secondary passage 13 to open the open end 15 of the divided secondary passage ( (See Figure 9). As a result, the intake air from the opening 10 flows not only into the main path 12 of the intake manifold but also into the three divided sub-paths 13. The intake port 17 of each combustion chamber 11 has an intake port side main passage 19 and an added intake port side secondary passage 2.
At the same time, intake air flows in from 0. Therefore, even if the amount of intake air is large as a whole, there is not much flow resistance applied to the intake air, and the inflow direction also shows a tendency to diffuse from the intake port 17 to the whole, and the generation of swirl S is small.

In this way, the intake device 7 shown in FIG. 4 operates one simplified butterfly valve 16 during low-load operation, and reliably connects each divided sub-path 13 and the intake port side sub-path 20 that follows it. Since this is shut off, a relatively small amount of intake air passes through only the main passage 19 on the intake port side, so that the flow velocity of intake air can be reliably increased and the inflow direction can be made most suitable for swirl S generation. Therefore, even if the amount of intake air is relatively small, a strong swirl S can be generated, the fuel can be mixed with the intake air early in the combustion chamber 11, and the combustion speed can be accelerated, resulting in increased output during low-load operation. I can contribute.
Furthermore, during high-load operation, a large amount of intake air is supplied to the combustion chamber 1 through the main passage and auxiliary passages 19 and 20 on the intake port side.
1, thereby reducing flow resistance and contributing to increased output. In particular, according to the present invention, since a single on-off valve is used, the number of parts and costs are reduced significantly, and there is no relative opening/closing deviation between the sub-paths.

In the above description, a three-cylinder diesel engine has been described, but the invention can also be applied to diesel engines with other numbers of cylinders. In that case, the intake manifold will have as many divided auxiliary passages as the number of cylinders. Furthermore, although the intake device 7 shown in FIG. 4 divides the flow path inside the intake port 14 into upper and lower sections, a vertical threshold wall 26 is used as in the intake port 25 shown in FIG. Side main road 2
7 and the sub-path 28 may be arranged on the left and right. In this case as well, similar to the intake system 7 shown in Fig. 4, a strong swirl S is generated during low load operation (Fig. 11a), and a strong swirl S is generated during high load operation (Fig. 11b).
In addition, it is possible to increase the output by reducing the flow resistance of intake air through the intake port.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main parts of the conventional intake system, Fig. 2 is a cross-sectional view of the main parts of the same intake system, Fig. 3 is an intake flow velocity-crank angle diagram of the same intake system, and Fig. 4 is a diagram of the intake system of this invention. A schematic perspective view of a main part of an intake device as an embodiment, FIG. 5 is a cross-sectional view taken along the line -- in FIG. 4, FIG. 6 is a cross-sectional view taken along the line -- in FIG. 4, and FIG.
8 and 9 are diagrams illustrating different functions of the intake device shown in FIG. 4, FIG. 10 is a side sectional view of main parts of the intake device shown in FIG. 4, and FIG.
The figure is a schematic explanatory diagram of an intake device as another embodiment of this invention. 7...Intake device, 9...Intake manifold, 1
0...Opening, 11...Combustion chamber, 12...Main passage, 1
3... Divided sub-route, 15... Opening side end, 16...
Bata valve, 17...Intake port, 19...Intake port side main path, 20...Intake port side secondary path.

Claims (1)

[Scope of utility model registration request] A main passage formed in the intake manifold of the internal combustion engine, an intake port side main passage communicating with the main passage and supplying intake air in a predetermined inflow direction to the combustion chamber of the internal combustion engine, and parallel to the main passage. a divided sub-path formed in the manifold in a shape, an intake port-side sub-path communicating with the divided sub-path and formed in parallel with the intake port-side main path, and each of the plurality of cylinders of the internal combustion engine. The opening end portions are arranged in parallel on the same plane on the upstream side of each of the sub-paths communicating with the combustion chamber, and the amount of intake air flowing into each of these opening end portions is simultaneously controlled and fully closed. A single opening/closing valve is provided for sealing each of the opening side ends in the above-mentioned state, and in addition to intake air from the main passage to each combustion chamber, by opening the opening/closing valve, air is drawn from the divided subsidiary passage. An intake system for internal combustion engines that can also supply intake air.