JPH07189688A - Muffler cooling device for engine - Google Patents

Abstract

PURPOSE:To effectively cool an exhaust muffler by means of cooling wind supplied from a cooling fan, to prevent a burn because of mistouching to a muffler cover, to sufficiently lower the temperature of exhaust gas passing inside the exhaust muffler, and to eliminate expansion noise due to the exhaust gas. CONSTITUTION:A shaft center 4 of a cooling fan 2 is arranged in the front face lateral position, which is in front of an engine main body 1 and is apart, from a cylinder center axial line 3 in the lateral direction, while a lateral side space 6 of the engine main body 1 is faced to a turning area 5 for the cooling fan 2. An exhaust muffler 7 is formed into an oblong in the longitudinal direction and is arranged in the lateral side space 6, while a clearance S, in which cooling wind is blown to flow in the longitudinal direction, is formed between the exhaust muffler 7 and a muffler cover 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine muffler cooling device, and more particularly to a device for effectively cooling an exhaust muffler with cooling air blown by a cooling fan.

[0002]

2. Description of the Related Art As a conventional technique of this type, there is one shown in FIGS. That is, as shown in FIG. 4, a cooling fan 102 is arranged on the front side of the engine body 101, and cooling air is blown toward the engine body 101 by the cooling fan 102. 10
4 is a front surface of the engine body 101, which is arranged so as to substantially coincide with the center axis 103 of the cylinder.
The main part of the front surface 01 is configured to face the swirl area 105 of the cooling fan 102.

Further, the exhaust muffler 107, viewed from the front side of the engine body 101, has a swirl region 1 of the cooling fan 102.
It is erected vertically at a lateral position apart from 05. The exhaust muffler 107 is covered with a muffler cover 108 capable of dissipating heat, as shown in FIG. 3, in order to prevent burns due to mistouching and fire during farming. That is, the muffler cover 108 is provided with a large number of heat dissipation holes 109 for promoting heat dissipation of the exhaust muffler 107.

[0004]

In the above-mentioned conventional example, the cooling air blows against the front surface of the engine body 101 and hardly reaches the exhaust muffler 107.
Due to insufficient cooling of itself, it is not possible to prevent burns due to a mistouch on the muffler cover 108. Further, the temperature of the exhaust gas passing through the exhaust muffler 107 is not sufficiently lowered, and the exhaust gas is discharged from the exhaust muffler 107 at a relatively high pressure, which causes a large expansion noise.
The present invention has been made in view of such circumstances, and an object thereof is to effectively cool the exhaust muffler with cooling air blown from a cooling fan to eliminate the above-mentioned inconvenience.

[0005]

In order to solve the above-mentioned problems, the present invention is characterized by being configured as follows. That is, the cooling fan 2 is arranged on the front side of the engine body 1, the cooling air is blown backward from the cooling fan 2 toward the engine body 1, and the exhaust muffler 7 is arranged on the side of the engine body 1. In the muffler cooling device for an engine in which the exhaust muffler 7 is covered with a muffler cover 8 capable of dissipating heat and the exhaust muffler 7 can be cooled by the cooling air, the axis 4 of the cooling fan 2 is connected to the engine main body 1. The exhaust muffler 7 is formed horizontally in the front-rear direction by arranging it in a front-side lateral position laterally deviated from the cylinder center axis line 3 on the front side and allowing the lateral space 6 of the engine body 1 to face the swirl region 5 of the cooling fan 2. And is arranged in the lateral space 6 and a gap S is formed between the exhaust muffler 7 and the muffler cover 8 so that cooling air blows in the front-rear direction.

[0006]

According to the present invention, a part of the cooling air blown by the cooling fan 2 passes through the lateral space 6 of the engine body 1, and this cooling air is exhausted by the exhaust muffler 7 and the muffler cover 8. Blows in the front-back direction through the gap formed between and. As a result, the muffler cover 8 is sufficiently cooled, and it is possible to prevent burns due to a mistouch on the muffler cover 8. Moreover, since the temperature of the exhaust gas passing through the exhaust muffler 7 is also sufficiently lowered, the expansion noise emitted from the exhaust muffler 7 is reduced.

[0007]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of an overhead cam type water-cooled two-cylinder gasoline engine according to an embodiment of the present invention. This engine body 1
As shown in FIG. 1, the cylinder head 12 is attached to the upper portion of the cylinder block 11, and the head cover 1 is attached to the upper portion thereof.
3 is assembled, and the gear case 14 and the belt case 14a are assembled to the front portion of the cylinder block 11. In the belt case 14a, the crank pulley 1
5, water pump input pulley 16, valve camshaft input pulley 1
7, a tension pulley 18 are arranged, and an endless belt 19 is wound around these. Further, an air cleaner 20 and an exhaust muffler 7 are arranged separately in the left and right lateral spaces of the cylinder head 12 that constitutes the engine body 1.

A radiator 30 is provided on the front side of the engine body 1 as shown by a virtual line in FIG. 1, and a cooling fan 2 is attached to a water pump input pulley 16.
On the back side of the water pump input pulley 16, a cooling water inlet 31 for introducing the returning cooling water from the radiator 30 is attached, and this is connected to a cylinder jacket (not shown) in the cylinder block 11. As a result, the cooling water is circulated in the order of the cylinder jacket 11, the head jacket 12, and the radiator 30 by the drive of the water pump while the engine is operating, and the cooling air generated by the cooling fan 2 passes through the radiator 30 to cool the cooling water. Heat exchange. The cooling air that has passed through the radiator 30 is blown backward by the cooling fan 2.

The characteristic structure according to the embodiment of the present invention will be described below. Here, FIG. 2 shows the exhaust muffler and the muffler cover, FIG. 2A is a cross-sectional plan view of the exhaust muffler and the muffler cover, and FIG. 2B is a vertical front view taken along line BB of FIG. 2A. is there. The exhaust system of this engine, as shown in FIG.
Two exhaust ports 58, 58 are led out from the water-cooled two-cylinder type cylinder head 12, and the exhaust ports 58 are connected to the exhaust pipe 5.
It is configured to communicate with the first expansion chamber 60 of the exhaust muffler 7 via 9.59. Reference numeral 35 in the figure is a V-shaped intake port.

As shown in FIG. 1, the water pump input pulley 16 provided with the cooling fan 2 is arranged at one vertex 57 on the right side of the belt case 14a. That is, the axial center 4 of the cooling fan 2 is arranged at a front side lateral position on the front side of the engine body 1 which is laterally deviated from the cylinder center axis line 3 to the right side, and the lateral space 6 of the engine body 1 in which the muffler 7 is arranged. Is configured to face the swirl area 5 of the cooling fan 2. As shown in FIG. 2 (A), the exhaust muffler 7 is formed in a horizontally long shape in the front-rear direction and is arranged in the lateral space 6. In this embodiment, the exhaust muffler 7 is not entirely located in the swirl area 5 of the cooling fan 2,
The entire exhaust muffler 7 may be located within the swirl area 5 of the cooling fan 2.

The exhaust muffler 7 is, as shown in FIG.
The exhaust muffler 7 covered with a heat dissipation muffler cover 8
A gap S is formed between the muffler cover 8 and the muffler cover 8 in the front-back direction. That is, the muffler cover 8 forms the gap S as shown in FIGS. 2 (A) and 2 (B), so that the exhaust muffler 7 is provided through the plurality of spacers 21.
It is fixed to. Further, the left half of the muffler cover 8 facing the cylinder head side and the left half of the lower side are open. This is because there is no risk of mis-touching in this range, and the heat dissipation of the exhaust muffler 7 is promoted.

A lower portion 8a on the front end side of the muffler cover 8 is expanded downward. This is for facilitating the intake of cooling air in the swirl area 5 of the cooling fan 2. As a result, the cooling air is sufficiently taken into the gap S, the muffler cover 8 is sufficiently cooled, and the muffler cover 8 is cooled.
It is possible to prevent burns due to a mistaken touch. Further, this also sufficiently lowers the temperature of the exhaust gas passing through the exhaust muffler 7, so that the expansion noise emitted from the exhaust muffler 7 is also reduced.

As shown in FIG. 2A, the exhaust muffler 7 is composed of a case body 40 which is long in the front-rear direction.
Inside 0, the first expansion chamber 41, the second expansion chamber 42,
The third expansion chamber 43 is partitioned and configured. From the rear end of the case body 40, a tail pipe 44 is led out through the central portions of the shield plate 42a and the perforated plate 42b. The front open end of the tail pipe 44 faces the inside of the first expansion chamber 41, the rear open end is open to the atmosphere, and a roll-shaped wire net 45 for suppressing intake of outside air is provided inside the rear end of the tail pipe 44. Has been done.

A large number of gas permeation holes 46 are formed in the tail pipe 44, and these are arranged in the second expansion chamber 42 and the third expansion chamber 43.
Facing inside. The inside of the tail pipe 44 is partitioned by a plug 47 provided at the same position in the front-rear direction as the porous plate 42a. Further, in the second expansion chamber 42, a cylindrical wall 48 provided with a large number of gas permeation holes is provided concentrically with the tail pipe 44. This exhaust muffler 7 introduces the high-temperature and high-pressure exhaust gas flowing out from each exhaust port 58 into the first expansion chamber 41, as shown by the arrow in FIG. The expansion noise of exhaust gas is further reduced because the pressure is released in the atmosphere after passing through the three expansion chambers 43 and in the process.

In this embodiment, as shown in FIG.
The exhaust muffler 7 is provided with two exhaust pipes 59, 59 of the same number as the exhaust ports 58, 58, and each exhaust pipe 59, 59 is inserted and fixed in the first expansion chamber 41 of the exhaust muffler 7, and each exhaust port 58. The exhaust gas flowing out of each of the 58 passes through each of the exhaust pipes 59, 59 and flows into the first expansion chamber 41 of the wide exhaust muffler 7 from the large number of exhaust holes 60. This eliminates the need for an exhaust manifold and allows the exhaust muffler 7 to approach the cylinder head 12, so that the front face of the exhaust muffler 7 is shown in FIG.
It is possible to face the rotation area 5 of the. Further, according to the above configuration, the heat of the exhaust gas is dispersed in the entire first expansion chamber 41, and the heat damage to the exhaust path due to the heat collection of the exhaust gas can be reduced.

Although the above-described embodiment has described the water-cooled two-cylinder gasoline engine of the overhead cam type, the present invention is not limited to the above-mentioned embodiment, and any engine other than the water-cooled engine can be used as long as the engine has a cooling fan. Liquid cooling engine,
The present invention can also be applied to an air-cooled engine. Further, not only the gasoline engine but also a gas engine, a diesel engine, a multi-cylinder engine with two or more cylinders, a single cylinder engine, and an overhead valve engine can be applied.

[Brief description of drawings]

FIG. 1 is a front view of an engine according to an embodiment of the present invention.

FIG. 2 shows an exhaust muffler and a muffler cover according to an embodiment of the present invention, FIG. 2A is a cross-sectional plan view of the exhaust muffler and muffler cover, and FIG. 2B is a BB line in FIG. 2A. It is a line vertical front view.

FIG. 3 is a vertical cross-sectional view of a muffler cover according to a conventional technique.

FIG. 4 is a front view of an engine according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine main body, 2 ... Cooling fan, 3 ... Cylinder center axis line, 4 ... Cooling fan axis center, 5 ... Turning area, 6 ... Lateral space, 7 ... Exhaust muffler
8 ... Muffler cover, S ... Gap.

Claims (1)

[Claims] 1. A cooling fan on the front side of the engine body (1)
(2) is arranged, and from this cooling fan (2) the engine body
The exhaust muffler (7) is arranged on the side of the engine body (1) so that the cooling air is blown backward toward (1), and the muffler cover (8) that can radiate the exhaust muffler (7) is disposed. )
In an engine muffler cooling device in which the exhaust muffler (7) is cooled by the cooling air, the shaft center (4) of the cooling fan (2) is attached to the front surface of the engine body (1) at the center axis of the cylinder. It is located laterally away from (3) and is located in the lateral position of the engine body (1).
(6) faces the swirl area (5) of the cooling fan (2), the exhaust muffler (7) is formed horizontally in the front-rear direction, and is arranged in the lateral space (6). ) And the muffler cover (8), a gap (S) in which cooling air blows in the front-back direction is formed.