JPS595178Y2 - Internal combustion engine intake system - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an intake system for an internal combustion engine.

In a multi-cylinder internal combustion engine, which is equipped with a carburetor above the intake manifold collecting part, and the air-fuel mixture supplied from the carburetor into the intake manifold collecting part is distributed into each intake manifold pipe, the air-fuel mixture is distributed through each intake manifold branch pipe. Equalizing the air-fuel ratio of the air-fuel mixture supplied into each cylinder, or the combustion process, is an extremely important issue from the viewpoint of exhaust emissions.

In addition, recirculated exhaust gas (hereinafter referred to as E
Even when EGR gas (referred to as GR) is supplied, it is necessary to uniformly distribute the supplied EGR gas to each cylinder.

The distribution of fuel and EGR gas to each cylinder is greatly affected by the shape of the intake manifold. Therefore, in the past, the distribution of fuel and EGR gas to each cylinder was achieved by changing the shape of the intake manifold in various ways. We are trying to equalize the

However, in reality, it is impossible to equalize the distribution of fuel and EGR gas to each cylinder simply by changing the shape of the intake manifold.

An object of the present invention is to provide an internal combustion engine that can simultaneously equalize the distribution of fuel and EGR gas to each cylinder.

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

Referring to FIGS. 1 and 2, 1 is the engine body, 2 is an intake manifold fixed to the engine body, 3 is a carburetor fixed to the intake manifold 2 via a heat insulating plate 4, and 5 is a Each exhaust manifold is shown, and an intake manifold riser portion 6 located below the carburetor 3 is exposed within the exhaust manifold 5.

Therefore, this riser portion 6 is heated by the exhaust gas flowing within the exhaust manifold 5.

As shown in FIG. 1, the carburetor 3 is composed of a primary carburetor A and a secondary carburetor B.

■The downstream carburetor A has a main nozzle 8 and a primary throttle valve 9 in its primary air horn 7, while the secondary carburetor B has a main nozzle 1 in its secondary air horn 10.
1 and a secondary throttle valve 12.

On the other hand, on the heat insulating plate 4, there are a pair of openings 13 and 1 which are aligned with the primary air horn 7 and the secondary air horn 10, respectively.
4 are formed, and the primary and secondary air horns 7.10 communicate into the intake manifold assembly 15 through these openings 13.14.

As shown in FIG. 1, a step 16 is formed above the opening 13, and a step 17 is formed above the opening 14 as well.

Furthermore, as shown in FIG. 1, a thin-walled hollow cylindrical tube 18 is inserted into the opening 13, and this thin-walled hollow cylindrical tube 18 has an outward annular flange 19 formed at its upper end abutting against the stepped portion 16. It is supported on the heat insulating board 4 by.

The inner diameter of the thin-walled hollow cylindrical tube 18 is approximately equal to the inner diameter of the primary air horn 7, and the thin-walled hollow cylindrical tube 18 has an open bottom portion 2 that is close to the riser portion 6 and is approximately parallel to the riser portion 6.
has 0.

On the other hand, an opening is formed on the side inner wall surface of the intake manifold assembly section 15 at approximately the same height as the opening bottom section 20 .

The EGR supply port 21 is connected to the side wall 22 of the intake manifold gathering part.
The EGR supply port 21 is connected to the exhaust manifold 5 via an EGR gas supply conduit 23, an EGR gas flow control valve 24, and an EGR gas supply conduit 25.

In the compound type carburetor 3 shown in FIG. 1, when the amount of depression of the accelerator pedal is small, the primary throttle valve 9 opens according to the amount of depression of the accelerator pedal, while the secondary throttle valve 12 opens as shown in FIG. It is held in the fully closed state as shown in the figure.

Next, when the accelerator pedal is further depressed and the opening degree of the primary throttle valve 9 reaches a predetermined opening degree or more, the secondary throttle valve 12 is opened in accordance with the amount of intake air.

In this way, the air-fuel mixture is constantly supplied into the intake manifold 2 via the primary air horn 7, and when the amount of intake air increases, the air-fuel mixture is also supplied into the intake manifold 2 from the secondary air horn 7.

During engine operation, the fuel sucked out from the main nozzles 8, 11 into the primary and secondary air horns 7.10, respectively, is not atomized sufficiently.
The fuel that descends within the secondary air horn 10 and then descends within the secondary air horn 10 collides with the stepped portion 17 to be atomized and stirred, and then flows into the intake manifold gathering portion 15 .

On the other hand, the fuel descending within the primary air horn 7 similarly collides with the annular flange 19 to be atomized and stirred, and flows into the thin-walled hollow cylindrical tube 18 .

The air-fuel mixture flowing inside the thin-walled hollow cylindrical tube 18 actually moves downward while moving up and down due to the intake pulsation, as shown by the arrows in FIG. 1, and during this time, the stirring action of the fuel and the intake air is further promoted.

Next, the air-fuel mixture that has flowed into the intake manifold collecting section 15 from the open bottom 20 of the thin-walled hollow cylindrical pipe 18 is supplied to each cylinder via each intake manifold branch pipe 26 a , 26 b , 26 C, 26 d.

As mentioned above, the stepped portions 16 and 17 and the thin-walled hollow cylindrical tube 18
By providing this, the atomization of the fuel supplied from the carburetor main nozzles 8, 11 is promoted, and thus the distribution of fuel to each cylinder becomes uniform.

On the other hand, a part of the EGR gas supplied from the EGR supply port 21 into the intake manifold collecting section 15 collides with the outer wall of the thin-walled hollow cylindrical tube 18 and forms the thin-walled hollow cylindrical tube 18 as shown by the arrow in FIG. The EGR gas flows through the gap between the side walls 22 of the intake manifold gathering part to the left and right, while the remaining EGR gas is drawn into the thin-walled hollow cylindrical tube 18 when the air-fuel mixture inside the thin-walled hollow cylindrical tube 18 rises due to intake pulsation. , thereby EG
The R gas and the mixture are well stirred.

In addition, the EG divided as shown by the arrow in Figure 2
The R gas flows through the gap between the open bottom 20 of the thin-walled hollow cylindrical pipe 18 and the riser part 6 to each intake manifold branch pipe 26 at high velocity.
a, 26b, 26C, and the mixture sucked into 26d.

In this way, the EGR inside the intake manifold gathering part 15
Since the stirring action of the gas and mixture is promoted, the E to each cylinder is reduced.
The distribution of GR gas will be uniform.

In addition, the air-fuel mixture in the primary air horn 7 is in the thin-walled hollow cylindrical tube 1.
8 and is brought into contact with the high-temperature riser portion 6 heated by the exhaust gas, so that the atomization of the fuel is further promoted.

Another embodiment is shown in FIGS. 3 and 4.

In this embodiment, a semicircular notch 27 is formed at the lower end of the thin-walled hollow cylindrical tube 18 facing the EGR supply port 21 .

By providing such a semicircular notch 27, the EG receives a stirring action inside the thin-walled hollow cylindrical tube 18.
The amount of R gas can be increased.

FIG. 5 shows yet another embodiment.

In this embodiment, the opening bottom 20 is formed as an inclined surface that rises toward the EGR supply port 21 side.

In this case as well, the stirring action is applied inside the thin-walled hollow cylindrical tube 18 as in FIG.

The amount of EGR gas can be increased.

FIG. 6 shows yet another embodiment.

In this embodiment, the opening bottom 20 is formed as an inclined surface that descends toward the EGR supply port 21 side.

In this case, the amount of EGR gas flowing increases as shown by the arrow in FIG. The amount of EGR gas received can be increased.

Still another embodiment is shown in FIG. 7 and FIG. 8.

In this embodiment, a tongue-shaped portion 28 that bends toward the EGR supply port 21 is formed at the lower end of the thin-walled hollow cylindrical tube 18 on the opposite side to the EGR supply port 21, and this tongue-shaped portion 28 allows the supply of electricity from the EGR supply port 21. EGR gas is guided into the thin-walled hollow cylindrical tube 18.

Therefore, in this embodiment, the amount of EGR gas subjected to the stirring action inside the thin-walled hollow cylindrical tube 18 can be increased, as in FIG. 3.

Further, in this embodiment, the tongue portion 28 is connected to the thin-walled hollow cylindrical tube 18.
It also plays the role of giving a stirring effect to the air-fuel mixture flowing out from the air.

FIGS. 9 and 10 show still another embodiment.

In this embodiment, a pair of holes 29 and 30 are formed on the outer peripheral wall surface of the thin-walled hollow cylindrical tube 18, and an EGR
Supply port 21 opens.

Further, as shown in FIG. 9, annular ribs 31 and 32 are formed on the inner wall surface of the thin hollow cylindrical tube around the base holes 29 and 30, respectively.

In this embodiment as well, E is supplied from the EGR supply port 21.
A part of the GR gas is divided to the left and right as shown by the arrows in Fig. 2, while the remaining EGR gas is distributed to 7L29,30.
The air flows into the thin-walled hollow cylindrical tube 18 through the air, and is subjected to a stirring action with the air-fuel mixture supplied from the primary air horn 7.

In addition, the air-fuel mixture flowing inside the thin-walled hollow cylindrical tube 18 flows through the stepped portion 16,
Atomization is promoted and stirred by the annular ribs 31 and 32, which perform the same function as 17.

As described above, according to the present invention, the atomization of the fuel, the stirring of the fuel and the intake air, and the stirring of the air-fuel mixture and the EGR gas are performed at the same time.
R gas distribution becomes extremely good.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of an internal combustion engine according to the present invention, Fig. 2 is a sectional view taken along line II-II in Fig. 1, Fig. 3 is a side sectional view of another embodiment, and Fig. 4. is IV-IV in Figure 3.
A side view of a thin-walled hollow cylindrical tube taken along a line, FIG. 5 is a side sectional view of yet another embodiment, FIG. 6 is a side sectional view of yet another embodiment, and FIG. 7 is yet another embodiment. Side sectional view of, No. 8
The figure is a side view of the thin-walled hollow cylindrical tube taken along the line Vllll-Vllll in FIG. 7, FIG. 9 is a side sectional view of yet another embodiment, and FIG. 10 is taken along the line X-X in FIG. FIG. 2 is a side view of a thin-walled hollow cylindrical tube. 2...Intake manifold, 3...Carburizer, 4...Insulation board, 7...Primary side air horn, 9...1 Next throttle valve, 10...
...Secondary side air horn, 12...Secondary side throttle valve, 16.17...Step part, 18...
...Thin-walled hollow cylindrical tube, 21...EGR supply port.

Claims (1)

[Scope of utility model registration request] A thin-walled hollow cylindrical tube that is aligned with the air horn of the carburetor and projects downward into the intake manifold gathering section is fixed to the lower end of the carburetor main body, and the bottom of the thin-walled hollow cylindrical tube is extended to the vicinity of the bottom wall of the intake manifold gathering section. At the same time, a gap is formed between the outer wall of the thin-walled hollow cylindrical tube and the side wall of the intake manifold gathering section, and the opening of the thin-walled hollow cylindrical tube communicates with the inside of the thin-walled hollow cylindrical tube and the inside of the intake manifold gathering section. An intake system for an internal combustion engine in which a recirculation exhaust gas supply port that opens at the opening is formed on a side wall of an intake manifold gathering part at approximately the same height as the opening.