JPS63295816A - Intake device for series four-cylinder internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the suction resistance and keep the proper air-fuel ratio and reduce the width of an intake device by arranging the suction passage axis lines or a ganged type carburetor so as to approach each other. CONSTITUTION:A pair of carburetors 2a and 2b connected with suction parts 4 and 5 are arranged so that the suction passage axis lines 6a and 6b are approached with each other in comparison with the middle point between the cylinders C1 and C2 and middle point between the cylinders C3 and C4. The parts corresponding to the second cylinder C2 and the third cylinder C3 of the suction parts 4 and 5 are bulged to the ganged type carburetor 2 side and connected with a circular-shaped balance tube 7 formed integrally with an intake manifold 3. Therefore, the width of the ganged type carburetor 2 can be reduced. Since the suction parts 4 and 5 communicate through the balance tube 7, the concentration of the mixed gas supplied into the second cylinder C2 and the third cylinder C3 in case of low temperature and low revolution speed can be prevented by reducing the width of the ganged type carburetor 2. Further, the generation of disturbance of the mixed gas is prevented. by the circular balance tube 7.

Description

Detailed Description of the Invention A9 Object of the Invention (1) Industrial Field of Application The present invention relates to a first, second, third and fourth cylinder arranged in series at equal intervals. An intake manifold connected to the ports includes a first intake part in a substantially Y-shape connected to the intake ports of the first and second cylinders, and a second intake part in the shape of a substantially Y-shape connected to each intake port of the third and fourth cylinders. The present invention relates to an intake system for an in-line four-cylinder internal combustion engine, in which a pair of carburetors constituting a dual carburetor are connected to the first and second intake parts.

(2) Prior Art Conventionally, in such an intake system, a pair of carburetors of a dual carburetor are arranged to correspond to the midpoint between the first and second cylinders and the midpoint between the third and fourth cylinders. It is common to do so.

(3) Problems to be Solved by the Invention By the way, if each carburetor is arranged so as to correspond to the midpoints between the first and second cylinders and between the third and fourth cylinders as described above, Since the width of the twin carburetor in the cylinder arrangement direction increases, there is a desire to reduce the width of the twin carburetor by arranging the carburetors close to each other. In this case, in the intake manifold, the first and second
The intake pipe portions corresponding to the second and third cylinders of the intake section are closer to the intake pipe axis of each carburetor. However, if fuel atomization is relatively poor at low temperatures and low rotation speeds, the fuel will flow closer to the intake path axis of each carburetor, so the fuel will flow closer to the intake path axis of each carburetor, that is, the second and The 'a mixture will be supplied to the third cylinder.

Therefore, as disclosed in Japanese Utility Model Application Publication No. 60-6873, for example, if the corresponding intake pipe portions of the first and second intake sections corresponding to the second and third cylinders are interconnected with a balance tube, For example, the first
Air containing almost no fuel flows from the second intake part through the balance tube into the rich air-fuel mixture flowing into the intake pipe section corresponding to the second cylinder of the intake part, and the air-fuel mixture is supplied to the second cylinder. can maintain an appropriate air-fuel ratio. However,
The balance tube disclosed in the above-mentioned publication is formed into a straight tube shape, and the air flowing from the balance tube disturbs the flow of the air-fuel mixture flowing through the intake section, increasing intake resistance.

In view of the above circumstances, the first object of the present invention is to make the width of a dual carburetor relatively small, and to maintain an appropriate air-fuel ratio at low temperatures and low rotation speeds while keeping intake resistance small. An object of the present invention is to provide an intake system for an in-line four-cylinder internal combustion engine.

By the way, when supplying secondary air to the intake manifold, it is necessary to supply the secondary air evenly to the intake ports of each cylinder, but the shape and shape of the conduit for supplying such secondary air It is difficult to select the diameter of the pipe, and if the pipe is installed separately from the intake manifold, it requires extra man-hours to connect the pipe to the intake manifold, increasing costs and is disadvantageous in terms of space. .

Therefore, a second object of the present invention is to achieve the first object and further provide a structure for uniformly supplying secondary air to each cylinder while reducing costs and reducing space. An object of the present invention is to provide an intake system for an in-line four-cylinder internal combustion engine that is advantageously constructed.

In addition, fuel-containing gas such as blow-by gas blown from the combustion chamber or evaporative gas released from the canister may be supplied to the intake manifold, and in this case as well, similar to the secondary air described above, each cylinder is It is necessary to supply gas evenly, and in this case, it is possible to construct a structure for supplying gas easily and in an advantageous manner in terms of space while reducing costs, as in the case of secondary air. desired.

A third object of the present invention is to achieve the first object and further provide a structure for uniformly supplying fuel-containing gas to each cylinder while reducing costs and reducing space. An object of the present invention is to provide an intake system for an in-line four-cylinder internal combustion engine that is advantageously constructed.

B0 Structure of the Invention (1) Means for Solving the Problems According to the first invention, the pair of carburetors have their intake passage axes at the midpoint between the first and second cylinders and at the midpoint between the third and second cylinders. The fourth cylinders are arranged closer to each other than the midpoint between them, and the part of the first intake part corresponding to the second cylinder and the part of the second intake part corresponding to the third cylinder are arranged in two series. It bulges toward the carburetor side and is connected to the intake manifold by an integrated arc-shaped balance tube.

According to the second invention, in addition to the configuration of the first invention, a secondary air supply pipe is connected to the balance tube.

Furthermore, according to the third aspect of the present invention, in addition to the configuration of the first aspect, the first and second intake sections are connected to the intake manifold by a communication pipe integrated with the intake manifold on the upstream side of the connection section of the balance tube. A gas supply pipe for mixing fuel-containing gas into intake air is connected to the communication pipe.

(2) Effects According to the configuration of the first invention described above, it is possible to reduce the width of the dual carburetor, and since the first and second intake portions communicate with each other via the balance tube, By reducing the width of the twin carburetor, the air-fuel mixture supplied to the second and third cylinders is prevented from becoming rich at low temperatures and low rotation speeds, and the balance tube bulges toward the twin carburetor side. The arcuate shape prevents turbulence in the air-fuel mixture and suppresses an increase in intake resistance.

Further, according to the configuration of the second invention, in addition to achieving the effects of the first invention, it is not necessary to provide a conduit for supplying secondary air separately from the intake manifold, thereby reducing costs. This also simplifies the structure and is advantageous in terms of space.

Further, according to the configuration of the third invention, in addition to achieving the effects of the first invention, by providing a communication pipe integrated with the intake manifold, gas containing fuel can be evenly supplied to each cylinder at a low cost. This can be achieved at low cost and with an hour wheel structure, and is also advantageous in terms of space.

(3) Examples Examples of the present invention will be explained below with reference to the drawings.
First, in FIG. 1 showing an embodiment of the first invention, an engine body 1 includes first, second, third and fourth cylinders CI, C2.
, C3, and C4 are arranged in series in this order at equal intervals. In order to supply air-fuel mixture to these cylinders C1 to C4, a side draft type dual carburetor 2 is connected to the engine body 1 via an intake manifold 3.

The intake manifold 3 has first and second cylinders C1 and C2.
It has a first intake part 4 for supplying the mixture to the cylinders C3 and C4, and a second intake part 5 for supplying the mixture to the third and fourth cylinders C3 and C4. The first intake section 4 is formed into a substantially Y-shape, including an intake pipe section 4a communicating with the intake port Pl of the first cylinder C1 and an intake pipe section 4b communicating with the intake port P2 of the second cylinder C2. The second intake section 5 is formed into a substantially Y-shape, including an intake pipe portion 5a that communicates with the intake port P3 of the third cylinder C3, and an intake pipe portion 5b that communicates with the intake port P4 of the fourth cylinder C4. .

The double carburetor 2 includes a carburetor 2a connected to the first intake part 4 and a carburetor 2b connected to the second intake part 5, which are connected to each other so as to operate in conjunction with each other. Moreover, these vaporizers 2a, 2b
In order to minimize the width of the dual carburetor 2 along the cylinder arrangement direction in the engine body 1, the intake path axis 6a is
, 6b are arranged closer to each other than the midpoint between the first and second cylinders C1 and C2 and the midpoint between the third and fourth cylinders C3 and C4. Therefore, the intake pipe axes 6a, 6b in each carburetor 2a, 2b correspond to the intake pipe portions 4b, 5a corresponding to the second and third cylinders C2°C3 in the first and second intake sections 4.5 in the intake manifold 3. Close to you.

first and second intake portions 4 in the intake manifold 3;
A balance tube 7 that communicates between the intake pipe portions 4b and 5a is integrally provided between the intake pipe portions 5 and 5.

Moreover, this balance tube 7 bulges toward the dual carburetor 2 side, that is, is formed in an arc shape centered on the engine body 1 side, and is formed at the joint between the balance tube 7 and the intake pipe portions 4b and 5a. Arc-shaped chamfered portions 8 and 9 are formed, respectively.

Next, to explain the operation of this embodiment, the air-fuel mixture containing fuel atomized by one carburetor 2a of the dual carburetor 2 is supplied to the first and second cylinders CI and C2 during their intake strokes. The fuel-air mixture containing fuel that is supplied and atomized by the other carburetor 2b is supplied to the third and fourth cylinders C3 and C4 during their intake strokes, respectively.

Assume that the second cylinder C2 is in the intake stroke at low temperature and low rotation speed. At this time, the fuel is not atomized well in one of the carburetors 2a, and the fuel flows near the intake path axis 6a. Therefore, it corresponds to the second cylinder C2 and the intake path axis 6
In the intake pipe portion 4b located closer to the a side, the air-fuel mixture becomes richer.

However, in the other carburetor C2, since the third and fourth cylinders C3 and C4 are not in the intake stroke, the amount of air flowing through them is small, and therefore the fuel is hardly atomized. This air containing almost no fuel flows into the intake pipe section 4b via the balance tube 7, and dilutes the rich air-fuel mixture from the carburetor 2a with air to form an air-fuel mixture with an appropriate concentration.

Moreover, since the balance tube 7 is formed in an arc shape that bulges toward the dual carburetor 2 side, air flows smoothly into the intake pipe portion 4b of the first intake portion 4, which is approximately Y-shaped. , it is possible to avoid turbulence in the air-fuel mixture as much as possible, and to suppress an increase in intake resistance. Further, since the chamfered portion 8.9 is provided at the joint portion of the balance tube 7 with both intake portions 4.5, the suction resistance at these joint portions can be reduced.

This effect is the same for the intake pipe portion 5a of the second intake section 5 corresponding to the third cylinder C3. Therefore, the width of the double carburetor 2 can be reduced by bringing the carburetors 2a and 2b close to each other. Despite being smaller, the second and third cylinders C2 and C
3, the mixture concentration can be maintained at an appropriate level at low temperatures and low rotation speeds.

2 and 3 show an embodiment of the second invention, and parts corresponding to the embodiment of FIG. 1 are given the same reference numerals.

A secondary air supply pipe 10 for supplying secondary air to the air-fuel mixture is connected to an approximately central upper portion of the balance tube 7, which is integral with the intake manifold 3 having a jacket 3a at the bottom thereof.

According to this structure, the secondary air supplied from the secondary air supply pipe 1o is transferred from the balance tube 7 to each intake pipe section 4.
a, 4b, 5a, and 5b, and the secondary air is evenly distributed to the cylinders C1 to C4 in the intake stroke.

Moreover, since the secondary air supply pipe 1O is connected to the intake manifold 3 and the balance tube 7 of the body, in addition to being able to achieve the effects of the embodiment shown in FIG.
In order to evenly distribute the secondary air to each cylinder C1 to C4, it is not necessary to provide a pipe line for supplying secondary air separately from the intake manifold 3, which simplifies the structure and reduces the number of pipes. There is no need for man-hours for connecting the pipes, so costs can be reduced, and furthermore, there is no need for space for providing the pipes.

4 and 5 show an embodiment of the third invention, and parts corresponding to the embodiment are given the same reference numerals.

Upstream of the balance tube 7 of the intake manifold 3, the first and second intake sections 4 and 5 are connected to the intake manifold 3.
are connected to each other by a communicating pipe 11 that is integrated with the
A gas supply pipe 12 for supplying fuel-containing gas such as blow-by gas or evaporated gas from a canister is connected to the gas supply pipe 12 .

In this way, in addition to producing the effects of the embodiment shown in FIG.
Moreover, since the communication pipe 11 is formed integrally with the intake manifold 3, it is advantageous in terms of man-hours and cost, and furthermore, it is advantageous in terms of space.

Effects of the C6 Invention As described above, according to the first invention, the pair of carburetors have their intake path axes from the midpoint between the first and second cylinders and from the midpoint between the third and fourth cylinders. The portions of the first intake section corresponding to the second cylinder and the portions of the second intake section corresponding to the third cylinder are bulged toward the dual carburetor side to provide intake air. Since it is connected to the manifold with an integrated arc-shaped balance tube, the width of the dual carburetor can be reduced and the mixture concentration supplied to the second and third cylinders can be maintained at an appropriate level at low temperatures and low rotation speeds. In addition, by making the balance tube arc-shaped, it is possible to prevent turbulence of the air-fuel mixture and suppress an increase in the intake tendency.

Further, according to the second invention, in addition to the configuration of the first invention, the balance tube is connected to the secondary air supply pipe, so that the secondary air supply pipe is connected to the balance tube. This eliminates the need to provide a pipe line separate from the intake manifold to supply air, which simplifies the structure and reduces costs. It also eliminates the need for man-hours for pipe connection, and also eliminates the need for pipe lines. This gives an advantage in terms of space.

Furthermore, according to the third invention, in addition to the configuration of the first invention, the first and second intake portions are connected by a communication pipe integrated with the intake manifold on the upstream side of the connection portion of the balance tube, and the communication Since a gas supply pipe for mixing fuel-containing gas into the intake air is connected to the pipe, the structure achieves the effects of the first invention and evenly distributes fuel-containing gas to each cylinder. Moreover, since the communication pipe is integrated with the intake manifold, there is no need for man-hours for connection, which reduces costs and is advantageous in terms of space.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the first invention, and FIGS. 2 and 3 show an embodiment of the second invention.
The figure is a plan view, FIG. 3 is a sectional view taken along the line ■-m in FIG. 2, FIGS. 4 and 5 show an embodiment of the third invention, and FIG. FIG. 5 is a sectional view taken along the line V-V in FIG. 4.

Claims (4)

[Claims] (1) first, arranged in sequence and in series at equal intervals;
An intake manifold connected to each intake port of the second, third, and fourth cylinders has a substantially Y-shaped first intake part connected to the intake ports of the first and second cylinders, and a first intake part connected to each intake port of the third and fourth cylinders. The in-line 4-cylinder has a substantially Y-shaped second intake part connected to an intake port, and a pair of carburetors forming a dual carburetor are connected to the first and second intake parts. In an intake system for an internal combustion engine, the pair of carburetors are arranged so that their intake path axes are closer to each other than the midpoint between the first and second cylinders and the midpoint between the third and fourth cylinders. The part of the first intake part corresponding to the second cylinder and the part of the second intake part corresponding to the third cylinder are arcuate balance tubes that bulge toward the dual carburetor side and are integrated with the intake manifold. An intake system for an in-line four-cylinder internal combustion engine, characterized in that the in-line four-cylinder internal combustion engine is connected. (2) An arc-shaped chamfered portion is formed at the joint portion of the balance tube with the first and second intake portions, wherein the series connection tube according to claim (1) Intake system for a 4-cylinder internal combustion engine. (3) the first, arranged sequentially and in series at equal intervals;
An intake manifold connected to each intake port of the second, third, and fourth cylinders has a substantially Y-shaped first intake part connected to the intake ports of the first and second cylinders, and a first intake part connected to each intake port of the third and fourth cylinders. The in-line 4-cylinder has a substantially Y-shaped second intake part connected to an intake port, and a pair of carburetors forming a dual carburetor are connected to the first and second intake parts. In an intake system for an internal combustion engine, the pair of carburetors are arranged so that their intake path axes are closer to each other than the midpoint between the first and second cylinders and the midpoint between the third and fourth cylinders. The part of the first intake part corresponding to the second cylinder and the part of the second intake part corresponding to the third cylinder are arcuate balance tubes that bulge toward the dual carburetor side and are integrated with the intake manifold. An intake system for an in-line four-cylinder internal combustion engine, wherein the balance tube is connected to a secondary air supply pipe. (4) the first, arranged sequentially and in series at equal intervals;
An intake manifold connected to each intake port of the second, third, and fourth cylinders has a substantially Y-shaped first intake part connected to the intake ports of the first and second cylinders, and a first intake part connected to each intake port of the third and fourth cylinders. The in-line 4-cylinder has a substantially Y-shaped second intake part connected to an intake port, and a pair of carburetors forming a dual carburetor are connected to the first and second intake parts. In an intake system for an internal combustion engine, the pair of carburetors are arranged so that their intake path axes are closer to each other than the midpoint between the first and second cylinders and the midpoint between the third and fourth cylinders. The part of the first intake part corresponding to the second cylinder and the part of the second intake part corresponding to the third cylinder are arcuate balance tubes that bulge toward the dual carburetor side and are integrated with the intake manifold. Upstream of the connection part of the balance tube, the first and second intake parts are connected to the intake manifold by a communication pipe integrated with the intake manifold, and the communication pipe includes a pipe for mixing fuel-containing gas into the intake air. An intake system for an in-line four-cylinder internal combustion engine, characterized in that a gas supply pipe is connected.