JPH0558828U - Exhaust silencer for forced air cooling overhead valve engine - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a silencer in which the air cleaner is not affected by the heat of the muffler and has a low exhaust noise. [Composition] Engine body for forced air-cooled overhead valve engine with intake / exhaust ports formed on the front and back of the engine body (1)
The air cleaners (12) are arranged on the left and right sides of the engine, and the muffler body (16) is arranged on the other side of the engine body (1) in the front-back direction. The muffler tail pipe (17) led out from the front end of the muffler body (1) is folded back and piped backward, and the sound absorbing material unit (20) is arranged at the tip of this muffler tail pipe (17). Muffler cover (1) and muffler tail tube (17)
The muffler cover (18) is covered with (18) and a part of the engine cooling air is forcedly ventilated.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an exhaust silencer for a forced air cooling overhead valve engine.

[0002]

[Prior art]

 Conventionally, in a single-cylinder forced air cooling overhead valve engine, for example, as disclosed in Japanese Utility Model Laid-Open No. 3-37250, a cooling fan is arranged in front of the engine body and the engine body is surrounded by the cooling fan. With a fan case on the front of the engine, an intake port on the front of the engine, and an exhaust port on the rear of the engine, and an air cleaner and muffler on the left and right sides of the engine. It has been configured.

[0003]

[Problems to be solved by the device]

 However, in the conventional forced air-cooled overhead valve engine, the air cleaner and the muffler were located on one side of the engine body, so the air cleaner was affected by the heat of the muffler and the combustion chamber of the engine was affected. There is a problem that the temperature of the inflowing combustion air rises and the charging efficiency decreases. There was also a problem that the muffler could not be cooled sufficiently because the muffler would be blown with warm air after cooling the engine. The present invention has been made in view of such a point, and an object thereof is to provide a silencer that does not affect the air cleaner due to the heat of the muffler and has a low exhaust noise.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, in the present invention, the air cleaners are arranged on the left and right sides of the engine body, and the muffler body is arranged on the left and right sides of the engine body in the front-rear direction and led out from the front end portion of the muffler body. The muffler tail tube is folded back and piped rearward, a sound absorbing unit is placed at the tip of this muffler tail tube, the muffler body and muffler tail tube are covered with a muffler cover, and the engine is placed in this muffler cover. The feature is that it is configured so that a part of the cooling air is forcedly ventilated.

[0005]

[Action]

 In the present invention, the air cleaners are arranged on the left and right sides of the engine body, the muffler bodies are arranged on the left and right sides of the engine body in the front-rear direction, and the muffler tail pipe led out from the front end portion of the muffler body is folded and formed. The muffler main pipe and muffler tail pipe with a muffler cover, and a part of the engine cooling air is forcedly ventilated into the muffler cover. Since it is configured, the muffler body and the long muffler tail tube can be strongly cooled to improve the sound deadening performance. Also, since the muffler and air cleaner are placed on the opposite side across the engine body, the air cleaner is not affected by heat from the muffler.

[0006]

【Example】

 FIG. 1 shows an embodiment of the present invention, FIG. 1 is an enlarged view of a main part, FIG. 2 is a partially longitudinal front view of an engine unit, FIG. 3 is a partially transverse plan view of the engine unit, and FIG. FIG. 5 is a perspective view showing the muffler device taken out. This engine unit accommodates the engine body (1) of a forced air cooling overhead valve engine in a decorative cover (2), and the interior of the decorative cover (2) is divided by two partition walls (3) into the decorative cover (2). Is partitioned into an engine body housing chamber (4), a muffler housing chamber (5), and an air cleaner housing chamber (6).

The engine body (1) of the forced air cooling overhead valve engine has an intake port (8) opened on the front wall of the head block (7) and an exhaust port (9) opened on the rear wall of the engine body. The front of (1) is covered with a fan case (10), and the engine cooling air generated by a cooling fan (11) arranged inside the fan case (10) flows from the front to the back in the engine housing chamber (4). Is formed. An air cleaner (12) and a carburetor (13) are housed in an air cleaner housing chamber (6) formed on the left side of the engine body housing chamber (4).

An exhaust muffler unit (14) is arranged along the front-rear direction in a muffler housing chamber (5) formed on the right side of the engine body housing chamber (4). The exhaust muffler unit (14) has a cylindrical muffler body (16) containing a catalyst inside, a muffler tail pipe (17) derived from the muffler body (16), and a muffler body (16) and a muffler tail pipe (16). It consists of a muffler cover (18) that covers the 17).

The muffler tail pipe (17) is led out forward from the front end wall (19) of the muffler body (16) and then folded back in a vertical plane to face the upper surface of the muffler body (16). The sound-absorbing material unit (20) such as glass wool is placed at the leading end of the exhaust, and the sound-absorbing material unit (20) has an opening formed in the rear end wall (21) of the muffler cover (18). It is placed facing the mouth (22). An exhaust port (23) corresponding to the exhaust port (22) is formed in the wall surface of the decorative cover (2) facing the rear end wall (21) of the muffler cover (18). Further, the muffler cover (18) is formed in a shape capable of covering the outer periphery of the other surface except the front surface side of the exhaust introduction pipe (24) connecting the exhaust port (9) and the muffler body (16).

The sound absorbing unit (20) is formed of a double cylinder whose inner wall is formed of a porous body (25) such as a wire mesh, and the sound absorbing material (26) such as glass wool is filled between the inner and outer walls. Further, a lid body (28) made of steel net is fitted to the tip of the exhaust passage (27) formed in the inner wall. The steel net lid (28) diffuses the exhaust gas discharge direction in order to prevent burn accidents caused by concentrated discharge of hot air.

The inside of the muffler cover (18) communicates with the inside of the fan case (10) at its front end portion, and a part of the engine cooling air generated by the cooling fan (11) is communicated with the muffler cover. It is constructed so that it is introduced into the (18) and flows from the front to the back in the muffler cover (18). The engine cooling air introduced into the muffler cover (18) is diverted at a portion near the rear end of the muffler cover (18) and opens into the rear end wall (21) of one muffler cover (18). Through the exhaust outlet (22), the exhaust outlet (23) of the makeup cover (2) is discharged to the outside of the makeup cover (2), and the other is circulated along the exhaust introduction pipe (24), and its end portion The cooling air vents (29) formed in the interior of the engine cover (2) flow into the decorative cover (2) and join the cooling exhaust air after cooling the engine body (1), and the rear surface of the engine housing chamber (4) It is designed to be discharged to the outside of the decorative cover (2) from an air outlet (30) formed in the decorative cover (2) corresponding to the side.

In the figure, reference numeral (31) is an air guide plate disposed in the engine body (1), and reference numeral (32) is an outside air intake passage formed in the decorative cover (2). The outside air intake passage (32) Is formed at the lower end of the air cleaner accommodating chamber (6), and the outside air intake (33) is opened at the lower rear side of the decorative cover (2). Part of the intake air flowing through the outside air intake passage (32) is sucked into the air cleaner (12) in the air cleaner storage chamber (6) as combustion air, and the remaining intake air is stored in the engine main body storage chamber. It flows into the part near the front end of (4) and flows into the fan case (10) as engine cooling air.

[0014]

[Effect of the device]

 In the present invention, since the muffler and the air cleaner are arranged so as to sandwich the engine body, the air cleaner is not affected by heat from the muffler, and the combustion air of low temperature can be supplied to the engine. The filling efficiency can be kept high. As a result, the engine output can be set high.

Further, the muffler main body is arranged in the front-back direction on the side of the engine main body, and the muffler main body and the muffler tail pipe derived from the muffler main body are covered with a muffler cover, and a part of the engine cooling air is placed inside the muffler cover. By blowing the engine cooling air introduced into the muffler cover to cool the muffler main body and the muffler tail pipe, the muffler tail pipe can be exposed to the engine cooling air, Since the amount of heat released from the muffler tail pipe can be increased, the engine exhaust can be cooled strongly and the exhaust outlet temperature can be lowered.

Furthermore, since the muffler tail pipe is led out from the front end of the muffler main body, and the derived muffler tail pipe is folded back and piped backward, the muffler tail pipe can be formed longer and the heat dissipation area is widened. Since the sound absorbing unit is located at the tip of the tail pipe of the muffler, the noise leaking from the exhaust system can be significantly reduced and the sound deadening performance can be further improved.

Furthermore, since the muffler body is arranged in the front-rear direction on the side portion of the engine body, and the muffler tail pipe led out from the front end wall of the muffler body is folded back, the muffler device is not attached to the engine body. The lateral projection size can be reduced, and it is possible to obtain an engine with high output and high noise reduction performance while suppressing an increase in the external dimensions of the engine.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part.

FIG. 2 is a partially longitudinal front view of an engine unit.

FIG. 3 is a partial cross-sectional plan view of an engine unit.

FIG. 4 is a partially longitudinal rear view of the engine unit.

FIG. 5 is a perspective view showing the muffler device taken out.

[Explanation of symbols]

1 ... Engine body, 8 ... Intake port, 9 ... Exhaust port, 10 ... Fan case, 11 ... Cooling fan, 12
… Air cleaner, 16… Muffler body,
17 ... Muffler tail tube, 18 ... Muffler cover,
20 ... Sound absorbing material unit.

Claims (1)

[Scope of utility model registration request] 1. An engine body of a forced air cooling overhead valve engine.
The fan case (10) is arranged so as to surround the cooling fan (11) arranged on the front side of (1), and the intake port (8) is arranged on the front surface of the engine body (1) and on the rear surface of the engine body (1). In a forced air cooling overhead valve engine with each exhaust port (9) opened, an air cleaner (12) is arranged on one side of the engine body (1), and a muffler body (16) is arranged on the other side of the engine body (1). Are arranged in the front-rear direction, the muffler tail pipe (17) derived from the front end of the muffler body (1) is folded back and piped backward, and the muffler tail pipe (17) has a sound absorbing unit (20 ) Is arranged, the muffler body (1) and the muffler tail pipe (17) are covered with a muffler cover (18), and a part of the engine cooling air is forcedly ventilated in the muffler cover (18). An exhaust silencer for a forced air-cooled overhead valve engine.