JPH04104126U - Internal combustion engine exhaust muffler structure - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an exhaust muffler with excellent safety by simultaneously lowering the surface temperature of the exhaust muffler and the temperature of exhaust gas discharged to the outside from the exhaust muffler. [Structure] A cooling jacket 4 is attached to the outer periphery of the exhaust muffler body 1 via a space layer 5, and the exhaust gas outlet 3 of the exhaust muffler body 1 is positioned upwind from the cooling air outlet 7 of the cooling jacket 4. establish.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is an air-cooled two-stroke system used in small working machines such as brush cutters and chainsaws. This invention relates to exhaust muffler structures for internal combustion engines such as gasoline engines.

0002

[Conventional technology]

In the two-stroke gasoline engines of small working machines as mentioned above, exhaust gas is It is discharged from the cylinder exhaust port to the exhaust muffler, where it is muffled and discharged to the outside. .

0003 By the way, in an internal combustion engine such as a two-stroke gasoline engine, Requires reduction of HC (hydrocarbons) and CO (carbon monoxide) in exhaust gas. Exhaust gas regulations are in place. Measures to comply with such exhaust gas regulations Conventionally, exhaust gas purification by the use of oxidation catalysts in the muffler and The exhaust gas discharged from the cylinder into the muffler is re-ignited and re-combusted. Therefore, methods are being adopted to reduce HC, CO, etc. in exhaust gas.

0004

[Problem that the idea aims to solve]

However, according to the above-mentioned conventional technology, the surface temperature of the exhaust muffler and The temperature of the exhaust gas discharged from the exhaust muffler to the outside increases, so In addition to severe wear and tear, there is also the risk of accidental contact with the device while carrying it, resulting in burns. There was a problem with the lack of safety.

[0005] This idea was made in view of the above circumstances, and it is based on the muffler surface temperature and muffler surface temperature. The purpose is to simultaneously lower the temperature of exhaust gas discharged from the be.

[0006]

[Means to solve the problem] In order to solve the above problem, this invention has an exhaust gas inlet 2 and an exhaust gas outlet 3. A cooling jacket 4 is mounted on the outside of an exhaust muffler body 1 having a space layer 5. The cooling jacket 4 has a cooling air blower that sends cooling air into the space layer 5. An opening 6 and a cooling air outlet 7 for discharging the cooling air flowing inside the space layer 5 to the outside are provided. The structure is such that the exhaust gas outlet 3 is provided at a position on the windward side of the cooling air outlet 7. It is something.

[0007]

[Effect]

A space layer 5 between the cooling air outlet 6 and the exhaust muffler body 1 and the cooling jacket 4 Cooling air from a cooling fan (not shown) etc. sent into the space passes through this space layer 5. By doing so, the exhaust muffler main body 1 is cooled from its surface.

[0008] In addition, the cooling air that has passed through the space layer 5 is discharged to the outside from the cooling air outlet 7. , the cooling air outlet 7 is located upwind from the exhaust gas outlet 3 provided in the exhaust muffler body 1. Because it is located on the side, the cooling air discharged from the cooling air outlet 7 and the exhaust gas outlet 3 The exhaust gas discharged from the Gas temperature can be lowered sufficiently.

[0009]

【Example】

An embodiment of this invention will be described below based on the drawings.

0010 FIG. 1 is a vertical cross-sectional view of essential parts showing an embodiment of the exhaust muffler structure according to this invention. Ru. The exhaust muffler body 1 is designed to reduce HC, CO, etc. in the exhaust gas. A catalyst equipped type with an oxidation catalyst or an air-cooled two-stroke engine (not shown) Exhaust by re-igniting and re-burning the exhaust gas discharged from cylinders such as It is configured as an afterburner type that removes HC, CO, etc. contained in the gas. Ru. This exhaust muffler body 1 contains exhaust gas discharged from a cylinder (not shown). an exhaust gas inlet 2 that introduces gas into the exhaust muffler body 1; Exhaust gas outlet 3 at the tip of the tail pipe that discharges the exhaust gas that has passed through the They are provided far apart from each other on the exhaust gas flow path.

[0011] The exhaust muffler main body 1 has a cooling jacket on its outer periphery via a space layer 5 having a predetermined width. Surrounded by ket 4. This cooling jacket 4 includes a ventilation fan (not shown). a cooling air outlet 6 for sending cooling air from the air into the space layer 5; A cooling air outlet 7 for discharging the cooling air flowing inside to the outside is provided with a cooling air outlet 7 for discharging the cooling air flowing inside the They are placed far apart from each other on the flow path. The cooling air sent into the space layer 5 is It takes in a part of the cooling air from the internal combustion engine's cooling system and uses it in the space layer 5. By flowing inside, the exhaust muffler main body 1 is cooled from the surface.

0012 The cooling air outlet 7 is provided with a relatively large diameter, and is mutually connected to the exhaust gas outlet 3. It is provided coaxially and at a position on the windward side of the exhaust gas outlet 3. others The exhaust gas outlet 3 located inward from the cooling air outlet 7 of the cooling jacket 4 The exhaust gas discharged from the cooling air outlet 7 is sufficiently mixed with the cooling air discharged from the cooling air outlet 7. It will be discharged outside.

[0013] Further, in the illustrated embodiment, a fire protection net 8 is attached to the cooling air outlet 7. fire protection The net 8 is for preventing sparks from flying out from the exhaust muffler body 1. In particular, the muffler body 1 is a catalyst-equipped muffler that heats up the exhaust gas. It is effective as a fire prevention measure when using an afterburner muffler.

[0014] In the embodiment shown in the drawings, the mating flange portion of the mating muffler body 1 Extends to the cooling jacket 4 to form a barrier section 9, which leads to higher temperature exhaust gas. Care should be taken to ensure that cooling air flows sufficiently toward the inlet 2 side, and the barrier portion 9 should be placed in an appropriate position. By arranging the inner cylinder 10 and applying the discharge force again, the leeward side can also be sufficiently cooled. It is composed of

[0015] In addition, in order to reinforce the inlet pipe part 11 of the muffler body 1, the cooling jacket 4 is A reinforced outer tube portion 12 is formed.

[0016] Note that an appropriate material can be used for the cooling jacket 4, but depending on the cooling air volume. If sufficient material is available, it is possible to further improve safety by using materials with excellent thermal insulation properties. However, if there is no surplus cooling air volume, use a material with excellent heat conductivity to cool the air. If necessary, such as using the jacket 4 itself as a radiator to increase cooling capacity, Appropriate changes can be made.

[0017]

[Effect of the idea]

According to this idea, the exhaust muffler is powered by cooling air flowing through the outer space layer. Cooling from the surface prevents the exhaust muffler from overheating, improving safety. It has advantages such as being expensive and having a long muffler life.

[0018] In addition, exhaust gas is discharged from the exhaust muffler and exhaust gas is discharged from the cooling air outlet. Because it is mixed with cooling air and discharged to the outside, it is possible to lower the temperature of the exhaust gas when it is discharged. It has the advantage of being highly safe.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a main part of an exhaust muffler structure according to an embodiment of the invention.

[Explanation of symbols]

1 Exhaust muffler body 2 Exhaust gas inlet 3 Exhaust gas outlet 4 Cooling jacket 5 Spatial layer 6 Cooling air vent 7 Cooling air outlet

Claims (1)

[Scope of utility model registration request] 1. A cooling jacket 4 is attached to the outside of an exhaust muffler body 1 having an exhaust gas inlet 2 and an exhaust gas outlet 3 with a space layer 5 interposed therebetween. A cooling air outlet 6 for sending cooling air into the space layer 5 and a cooling air outlet 7 for discharging the cooling air flowing in the space layer 5 to the outside are provided, and the exhaust gas outlet 3 is located upwind of the cooling air outlet 7. An exhaust muffler structure for an internal combustion engine, characterized in that it is provided in the position of.