JPH0771313A - Engine intake system - Google Patents

Abstract

(57) [Summary] [Structure] The engine air intake system was designed as follows. That is, the plurality of intake ports 2 and 2 are formed as a branched structure in which the respective base ends merge. And the confluence part 5
The common intake port inlet 6 formed in the
It communicated with the intake port 4 of. [Effect] The intake air supplied from the intake air outlet 4 of the intake air supply device 3 is distributed to the intake ports 2.2 through the confluence portion 5. For this reason, the intake manifold is not required, so that the engine manufacturing cost can be reduced and the engine can be downsized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine air intake device, and more particularly, to reduce the manufacturing cost of the engine.
The present invention relates to a compact engine.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional art of an engine intake device.
There is one shown in. Like the present invention, it has the following basic structure. That is, the cylinder head 10
1, a plurality of intake ports 102, 102 are internally provided, and the intake ports 102, 102 are connected to the intake outlet 104 of the intake supply device 103. In this prior art, the intake air supply device 103 is composed of the air cleaner 120 and the carburetor 154.

In the engine having such a basic structure, the intake air supplied from the intake air outlet 104 of the intake air supply device 103 is introduced into the combustion chamber through the intake ports 102, 102.

By the way, in this prior art, the plurality of intake ports 102, 102 are formed individually and independently, and the plurality of intake port inlets 106, 106 are provided in the intake manifold 10.
7 is connected to the intake outlet 104 of the intake supply device 103.

[0005]

The above-mentioned conventional techniques have the following problems. The use of intake manifold 107 with a complex branch structure increases engine manufacturing costs.

Due to the presence of the intake manifold 107, the intake supply device 103 is separated from the cylinder head 101 and overhangs greatly in the width direction or the height direction of the engine, thus increasing the size of the engine.

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine intake device which can reduce the manufacturing cost of the engine and make the engine compact.

[0008]

According to the present invention, as illustrated in FIG. 1, a plurality of intake ports 2.2 are provided in a cylinder head 1.
The intake device for an engine, which is configured by connecting the intake port 2 to the intake outlet 4 of the intake supply device 3, is characterized by the following.

That is, a plurality of intake ports 2 and 2 are formed as a branched structure in which respective base end portions are joined, and a common intake port inlet 6 formed in the joining portion 5 is connected to the intake outlet 4 of the intake supply device 3. It is characterized by being configured to communicate with each other.

[0010]

[Operation and effect of the invention]

(First Invention) As illustrated in FIG. 1, the present invention has the following operations and effects. The intake air supplied from the intake air outlet 4 of the intake air supply device 3 is
It is distributed to the respective suction ports 2 and 2 via the confluence section 5. Therefore, the intake manifold having a complicated branch pipe structure is not required, and the engine manufacturing cost is reduced.

Since the intake manifold is not required, the intake supply device 3 can be brought close to the cylinder head 1, and the overhanging dimension of the intake supply device 3 in the width direction and the height direction of the engine can be shortened, so that the engine can be made compact. Can be realized.

[0012]

Embodiments of the present invention will be described with reference to the drawings.
1 to 4 are views for explaining a water-cooled two-cylinder gasoline engine of an overhead cam type according to an embodiment of the present invention. The structure of this engine is as follows. That is, as shown in FIG. 3, the cylinder head 1 is assembled to the upper part of the cylinder block 11, the head cover 12 is assembled to the upper part thereof, and the gear case 13 and the belt case 14 are assembled to the front part of the cylinder block 11. . As shown in FIG. 4, in the belt case 14, the crank pulley 1
5, water pump input pulley 16, valve camshaft input pulley 1
7 and a tension pulley 18 are arranged, and an interlocking belt 19 is wound around them.

An air cleaner 20 and an exhaust muffler 3 are separately arranged on the left and right of the cylinder head 1.
As shown in FIG. 2 or 3, an ignition coil 21 and an igniter 22 are attached to the rear portion of the cylinder head 1. A rear end plate 23 is attached to the rear portion of the cylinder block 11, and a flywheel 25 connected to a crankshaft 24 is arranged on the rear side thereof. A ring gear 26 is externally fitted and fixed to the flywheel 25, and as shown in FIG. 2, a starter motor 27 is supported on the right side of the rear end plate 23. The pinion gear 28 of the starter motor 27 is meshed with the ring gear 26. The ignition coil 21 and the igniter 22 are provided above and facing the ring gear 26, and are cooled by the flow of air in the rear portion of the engine caused by the rotation of the ring gear 26.

The structure of the water cooling device of this engine is as follows. That is, as shown in FIG. 4, the cooling fan 29 is attached to the water pump input pulley 16, and the radiator 30 is arranged in front of it. Belt case 14
Is formed in a triangular shape when viewed from the front, and one apex portion 57 on the right side thereof is projected to the lateral side of the cylinder head 1 and the cylinder block 11, and as shown in FIG. An inlet case 31 is attached and communicates with a cylinder jacket (not shown) in the cylinder block 11. Also, the cylinder head 1 and the belt case 1
In the gap between the cylinder head 1 and the cooling water outlet case 3
2 is attached, which is the head jacket 33 shown in FIG.
Is in communication with. The head jacket 33 and the cylinder jacket communicate with each other through a water passage 34.

In this water cooling device, while the engine is operating, the cooling water is circulated in the order of the cylinder jacket, the head jacket 33, and the radiator 30 by driving the water pump, and the cooling air is passed by the cooling fan 29 through the radiator 30. , Cool the engine with water.

As shown in FIG. 1, the exhaust system of this engine is provided with two exhaust ports 35, 35 inside the cylinder head 1 near the front and rear ends thereof, and the exhaust port outlets 8.8 thereof are exhaust mufflers. 36 is connected to the first expansion chamber 37.

The structure of the exhaust muffler 36 is as follows.
That is, the shielding plate 4 in the central portion is inside the case 39 that is long in the front and rear.
0 and the perforated plate 41 near the rear end, and the first expansion chamber 37, the second expansion chamber 42, and the third expansion chamber 43 are sequentially arranged from the front side.
Are sectioned. Further, an exhaust outlet pipe 44 penetrating both central portions of the porous plate 41 and the shielding plate 40 is inserted from the rear end portion of the case 39, and the front end opening portion 45 thereof has a front end opening portion 45.
7, the rear end opening 46 is opened to the atmosphere, and a roll-shaped wire net 47 that suppresses suction of outside air is provided inside the rear end. A large number of gas permeation holes 48 are provided in the exhaust outlet pipe 44.
Are opened and these are in the second expansion chamber 42 and the third expansion chamber 4
It is facing within 3. The inside of the exhaust outlet pipe 44 is partitioned by a plug 49 provided at the same position in the front-rear direction as the porous plate 41. In the second expansion chamber 42, a cylindrical wall 51 having a large number of gas permeation holes 50 is internally provided concentrically with the exhaust outlet pipe 44.

In the exhaust system having the exhaust muffler 36, as shown by the arrows in FIG. 1, the high-temperature and high-pressure exhaust gas flowing out from each exhaust port 35 is introduced into the first expansion chamber 37,
Sequentially passing through the second expansion chamber 42 and the third expansion chamber 43, the pressure is reduced in the process and then released into the atmosphere to reduce the expansion noise of the exhaust gas.

The structure of the intake system of this engine is as follows. That is, as shown in FIG. 1, two intake ports 2.2 are internally provided near the center of the cylinder head 1. In addition, the air cleaner 20 and the carburetor 54
And constitute the intake air supply device 3. The intake ports 2.2 are communicated with the air-fuel mixture outlet 61 of the carburetor 54. The carburetor inlet 38 is the air cleaner 20.
Is in communication with. Then, as shown in FIG. 3, the carburetor 3 is linked to the speed control lever 61 via the governor device 55.

In this embodiment, in order to reduce the manufacturing cost of the engine and make the engine compact, the intake device is devised as follows. That is, the two intake ports 2 and 2 are formed as a branched structure in which the respective base end portions are joined, and the common intake port inlet 6 formed in the joining portion 5 communicates with the mixture air outlet 61 of the carburetor 54. It is configured. The air-fuel mixture outlet 61 is connected to the intake port inlet 6 via the insulator 56. The air-fuel mixture outlet 61 may be directly connected to the intake port inlet 6.

According to such a configuration, the carburetor 5
The air-fuel mixture supplied from the air-fuel mixture outlet 61 of FIG.
Is distributed to each intake port 2.2. For this reason, the intake manifold having a complicated branch pipe structure becomes unnecessary,
Engine manufacturing costs are reduced. Further, since the intake manifold is not required, the intake supply device 3 can be brought close to the cylinder head 1, and the overhanging dimension of the intake supply device 3 in the width direction and the height direction of the engine can be shortened, so that the engine can be downsized. Can be achieved. Furthermore, by removing the intake manifold, which has a curved structure at relatively low temperatures,
Condensation of the air-fuel mixture on the inner peripheral surface of the intake manifold disappears,
Speed control response and startability are improved.

Further, in this embodiment, the exhaust muffler 36 has two exhaust introduction pipes 9 and 9 of the same number as the exhaust ports 35 and 35.
And the two exhaust introduction pipes 9 and 9 are inserted and fixed in the first expansion chamber 37 of the exhaust muffler 36, and the respective exhaust introduction pipe outlets 10 and 10 are individually installed in the first expansion chamber of the exhaust muffler 36. It is located in 37. Also, the two exhaust introduction pipe inlets 52, 52 are individually connected to the two exhaust port outlets 8.8.

As a result, the two exhaust ports 35
The exhaust gas flowing out from each of the exhaust gas passes individually through the two exhaust introduction pipes 9 and joins in the wide first expansion chamber 37 of the exhaust muffler 36, so that the heat of the exhaust gas is first expanded. Dispersed over the entire chamber 37, heat damage to the exhaust path due to heat collection of exhaust gas is reduced. Also, a plurality of exhaust ports 35.3
Since the exhaust gas flowing out from each of the exhaust gas No. 5 and the exhaust gas exhaust pipes 9 can be joined to the first expansion chamber 37 of the exhaust muffler 36, the exhaust manifold becomes unnecessary, and the engine manufacturing cost is reduced. It will be cheaper and the engine can be made smaller.

Further, in this embodiment, as shown in FIG. 4, the water pump input pulley 16 provided with the cooling fan 29 is arranged at the one apex portion 57 on the right side of the belt case 14, and viewed from the front of the engine. Cylinder center axis 5
A turning center 58 of the cooling fan 29 is arranged at a position deviated to the right side from 9. A part of the swirling area 60 of the cooling fan 29 faces the lateral space of the engine from the front side thereof. The exhaust muffler 36 and the starter motor 27 are arranged in the lateral side space of the engine, and a part of the front side of these is opposed to a part of the swirl region 60 of the cooling fan 29 from the rear side. The exhaust muffler 36 and the front side portion of the starter motor 27 may entirely face a part of the swirl region 60 of the cooling fan 29. With such a configuration, the cooling wind generated by the cooling fan 29 blows against the exhaust muffler 36 and the starter motor 27 to cool them by air.

The contents of the embodiments of the present invention are as described above, but the present invention is not limited to the above embodiments. For example, although the above embodiment has been described with reference to an overhead cam type water-cooled two-cylinder gasoline engine, the present invention can be applied to any engine having a plurality of intake ports. For this reason,
The present invention can be applied not only to an engine having three or more cylinders but also to a single cylinder engine as long as it has a plurality of intake ports such as a multi-valve engine. Further, the invention is not limited to gasoline engines, but can be applied to gas engines and diesel engines. It can also be applied to liquid-cooled engines other than water-cooled engines, air-cooled engines, and overhead valve engines.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of the vicinity of a cylinder head of an engine according to an embodiment of the present invention.

FIG. 2 is a plan view of the engine according to the embodiment of the present invention.

FIG. 3 is a side view of the engine according to the embodiment of the present invention.

FIG. 4 is a front view of the engine according to the embodiment of the present invention, in which the front portion of the belt case is removed.

FIG. 5 is a view corresponding to FIG. 1 of an engine according to a conventional technique.

[Explanation of symbols]

1 ... Cylinder head, 2 ... Intake port, 3 ... Intake supply device, 4 ... Intake outlet, 5 ... Confluence part, 6 ... Intake port inlet.

Front page continuation (72) Inventor Naoki Inoue 64 Ishizukita-machi, Sakai City, Osaka Prefecture Kubota Sakai Factory

Claims (1)

[Claims] 1. A plurality of intake ports on a cylinder head (1)
(2)-(2) are provided internally, and the intake ports (2)-(2) are connected to the intake outlet (4) of the intake supply device (3). The intake ports (2) and (2) are formed as a branched structure in which the respective base ends merge, and the common intake port inlet (6) formed in the merged part (5) is the intake of the intake supply device (3). Exit (4)
An air intake device for an engine, which is configured to communicate with the.