JPH078524U - Exhaust device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to an exhaust device for an internal combustion engine of an automobile, etc.
The purpose of the invention is to increase the heat insulation effect of the exhaust pipe having the inner and outer double structure and to reduce the radiated sound from the inside of the exhaust pipe. A structure of an exhaust system for an internal combustion engine in which an exhaust pipe 1 is composed of an inner pipe 11 and an outer pipe 12 so as to have an inner and outer double structure.
Ceramic wool 4 is filled on the inner tube side between 1 and 12, and glass wool 5 or rock wool is filled between the inner surface of the outer tube and the inner surface of the outer tube.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an exhaust system for an internal combustion engine of an automobile or the like, and more particularly to an exhaust system in which exhaust pipes are dually formed.

[0002]

[Prior art]

 For example, an exhaust system for an internal combustion engine of an automobile is generally configured such that exhaust gas from the engine is guided to a catalytic converter via an exhaust pipe, and further guided from the catalytic converter to a silencer via an exhaust pipe. Then, in order to maintain the temperature of the exhaust gas guided from the engine to the catalytic converter above a predetermined temperature, or to suppress the rise in the surface temperature of the exhaust pipe, the exhaust pipe, particularly the engine, is connected to the catalytic converter. It is known that the exhaust pipes reaching the inner and outer pipes are double-sided.

[0003]

[Problems to be solved by the device]

 However, since the conventional exhaust pipe has a hollow double structure in which a space is simply provided between the inner and outer pipes, the adiabatic function is not always sufficient, and the exhaust temperature introduced to the catalytic converter is lowered, and the surface of the exhaust pipe is reduced. There was a problem such as an increase in temperature. Further, recently, in the exhaust system of this type, noise regulation tends to be further strengthened, and it is desired to reduce the radiated sound (transmitted sound) from the exhaust pipe, which has not been a problem so far.

Therefore, it is conceivable to fill the space between the inner and outer pipes with a heat insulating material such as glass wool or rock wool that also serves as a sound absorbing material, but the glass wool or rock wool normally used in this type of exhaust device is considered. Does not necessarily have a sufficient heat resistance temperature, and if it is installed near the facility, it may be deteriorated by heat from the exhaust gas passing through the inner pipe, resulting in a decrease in elasticity and sound absorption performance.

The present invention has been proposed in view of the above problems, and even when the above sound absorbing material is provided between the inner and outer pipes, particularly near the engine, there is no fear of heat deterioration. An object of the present invention is to provide an exhaust system for an internal combustion engine that can maintain good elasticity and sound absorption performance.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, an exhaust system for an internal combustion engine according to the present invention has the following configuration. That is, in an exhaust system for an internal combustion engine in which the exhaust pipe is composed of an inner pipe and an outer pipe, the inner and outer pipes are made of ceramic wool on the inner pipe side and the glass wool on the outer pipe inner surface. Alternatively, it is characterized by being filled with rock wool.

[0007]

[Action]

 By filling ceramic wool on the inner tube side between the inner tube and the outer tube and glass wool or rock wool between the outer tube and the inner surface of the outer tube as described above, it is possible to increase the heat insulation effect, and at the same time, to increase the ceramic wool or glass wool. Alternatively, the sound absorption effect of rock wool can reduce the radiated sound. In addition, by providing ceramic wool with good heat resistance on the inner tube side between the inner tube and the outer tube, there is a risk that the ceramic wool, glass wool, or rock wool will deteriorate due to heat, even in a high temperature region close to the facility. Therefore, it is possible to maintain the elasticity and sound absorption performance in good condition.

[0008]

【Example】

 Hereinafter, an exhaust device for an internal combustion engine according to the present invention will be described in detail with reference to an embodiment shown in the drawings. FIG. 1 is a side view showing an embodiment of an exhaust system for an internal combustion engine, and FIG. 2 is a transverse sectional view thereof. In the figure, 1 is an exhaust pipe, one end (left end in FIG. 1) of the exhaust pipe 1 is connected to an exhaust manifold of an internal combustion engine (not shown) via a connecting flange 2, and the other end of the exhaust pipe 1 is connected. The muffler is connected via a catalytic converter and an exhaust pipe, but is omitted in the figure. Reference numeral 3 in the figure is a flange for connecting the catalytic converter.

As shown in FIG. 2, the exhaust pipe 1 is composed of an inner pipe 11 and an outer pipe 12 in an inner and outer double structure, and a ceramic wool 4 is further provided on the outer periphery of the inner pipe between the inner and outer pipes 11 and 12. In this embodiment, glass wool 5 is filled between the outer circumference and the inner surface of the outer tube.

The material of the above-mentioned ceramic wool 4 and glass wool 5 is appropriate, but in this embodiment, the ceramic wool 4 is made of Al ₂ O ₃ and SiO ₂ and has an average fiber diameter of about 2.8 μm. A ceramic fiber formed into a mat is used, and the maximum operating temperature (heat resistant temperature) thereof is about 1260 ° C to 1430 ° C. Further, as the glass wool 5, in the present embodiment, a glass fiber containing SiO ₂ as a main component and having an average fiber diameter of about 9 μm containing Al ₂ O ₃ , CaO and other metal oxides in a mat shape is used. The maximum operating temperature is about 400 ° C to 500 ° C. Instead of the glass wool 5, so-called rock wool may be used.

The method of filling the above-mentioned ceramic wool 4, glass wool 5, or rock wool between the inner and outer tubes 11 and 12 is appropriate, but for example, before loading the inner tube 11 into the outer tube 12, The ceramic wool 4 formed in a mat shape as described above is wound around the outer periphery of the reference numeral 11, and the glass wool 5 or rock wool similarly formed in a mat shape is wound around the outer periphery thereof in a predetermined thickness. Then, it may be loaded into the outer tube 12.

Although the above embodiment has a configuration in which one inner tube 11 is arranged inside the outer tube 12, the present invention is not limited to this, and can be applied to various configurations, for example, as shown in FIG. As shown in the figure, it is also applicable to a case where a plurality of inner tubes 11 are arranged inside the outer tube 12. Also, in the case of FIG. 3 (a), the outer pipe 12 is divided into upper and lower halves, and the mating surfaces thereof are fixed by welding or the like. For example, as shown in FIG. Can also be applied to the one divided into two and the like as described above.

[0013]

[Effect of device]

 As described above, according to the present invention, since the ceramic wool 4 and the glass wool 5 or the rock wool are filled between the inner and outer pipes 11 and 12 of the exhaust pipe 1 having the double inner and outer structure, the exhaust pipe is hollow as in the conventional case. Compared with the double structure, the heat insulating effect can be greatly increased, and the radiation sound can be reduced by the sound absorbing effect of the ceramic wool 4 and the glass wool 5 or the rock wool. Further, since the ceramic wool 4 having a high heat resistant temperature is provided on the inner tube 11 side between the inner and outer tubes 11 and 12, even when it is provided in a position close to the engine, the ceramic wool 4, the glass wool 5 or the rock wool can be heated by exhaust heat. There is little risk of deterioration, and good elasticity and sound absorption performance can be maintained. Moreover, when only the ceramic wool is filled between the inner and outer pipes, the elastic force of the ceramic wool is smaller than that of glass wool or rock wool. Although the pipe may vibrate and generate noise, glass wool or rock wool, which is more elastic than that, is also used, so that the inner and outer pipes can be held satisfactorily and stably with a relatively small packing density. be able to. In addition, glass wool and rock wool are generally cheaper than ceramic wool, so the manufacturing cost can be reduced compared to when only ceramic wool is filled, and glass wool and rock wool have better sound absorption performance than ceramic wool. There is an effect that the sound and the like can be favorably reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an exhaust system for an internal combustion engine according to the present invention.

2 is an enlarged cross-sectional view taken along the line AA in FIG.

3A and 3B are cross-sectional views showing another embodiment of the exhaust system for an internal combustion engine according to the present invention.

[Explanation of symbols]

 1 Exhaust pipe 11 Inner pipe 12 Outer pipe 4 Ceramic wool 5 Glass wool

Claims (1)

[Scope of utility model registration request] 1. An exhaust system for an internal combustion engine, wherein an exhaust pipe is composed of an inner pipe and an outer pipe so that the inner and outer pipes are dual, and ceramic wool is provided on the inner pipe side between the inner and outer pipes and between the outer pipe inner surface and the outer surface thereof. An exhaust system for an internal combustion engine, characterized by being filled with glass wool or rock wool.