JPH0625542B2 - Exhaust stack enclosing member - Google Patents

Description

TECHNICAL FIELD The present invention relates to a member for surrounding an exhaust pipe system of an internal combustion engine.

2. Description of the Related Art Exhaust pipe systems of internal combustion engines, such as automobile engines, generally include a purifying unit, a silencer unit, and a connecting pipe unit. The exhaust pipe system is usually covered with a surrounding member. This coating is intended for thermal insulation to protect other adjacent components from the heat of the exhaust pipe system, which becomes hot.
However, in view of the fact that the exhaust pipe system vibrates due to the explosive operation of the internal combustion engine, etc., and this vibration can be a noise source, it is desirable that the coating also has a silencing effect. That is, it is desired that the surrounding member has a sound deadening function as well as a heat insulating function.

Conventionally, as the surrounding member, a member in which a woven wire mesh is fixed to a frame has been proposed (Japanese Utility Model Laid-Open No. 55-73512). This is intended to overcome the problem of noise due to vibration, which has been used in the conventional thin iron plate molded body.

However, in the above-mentioned surrounding member, since the exhaust pipe system is substantially covered with the woven wire mesh, its heat insulating property and sound deadening property are not sufficiently satisfied.

Means for Solving the Problems The present invention has been made for the purpose of developing an enclosing member having excellent heat insulating properties and sound deadening properties by overcoming the above problems.

That is, the present invention is spot welding between the upper and lower knitting meshes of the fiber mat in a compression-flattened fiber mat with holes interspersed in a cylindrical knitting mesh. The present invention provides an exhaust pipe surrounding member for surrounding an exhaust pipe system of an internal combustion engine.

Action With the above configuration, the surrounding member can have a heat insulating function, a sound deadening function, and a vibration absorbing function based on the fiber mat, and since the upper and lower wire nets are partially connected, the fiber mat Can be reinforced and supported by a wire mesh, and can have excellent resistance to mechanical properties such as vibration resistance. On the other hand, when the exhaust pipe system is surrounded by the laminate, a wire mesh is interposed between the exhaust pipe system and the fiber mat, and an air layer is formed between the exhaust pipe system and the fiber mat. The layers exert a heat insulating function.

Example As in the example shown in FIG. 1, the exhaust pipe enclosing member of the present invention has a compression flatness obtained by interposing a fiber mat 3 having holes 4 interspersed with a cylindrical metal mesh 2 formed by knitting or the like. Then, the upper and lower braided meshes of the fiber mat are spot-welded to each other through the holes 4 scattered in the fiber mat, whereby the fiber mat 3 is fixed between the upper and lower braided meshes.

The enclosure member of the present invention is not limited to the configuration example of the above embodiment. The number of wire mesh layers and the number of fiber mat layers in the surrounding member may be singular or plural, and the laminated form such as a repeating laminated unit of the wire mesh layer and the fiber mat layer is appropriately determined. In addition, the outer shape of the wire mesh itself or the entire laminate is corrugated so that the outer shape thereof is appropriately determined.

In the present invention, a knitted metal net such as a knitted knit is preferably used in terms of its elasticity and flexibility.

Further, as the fiber mat, heat-resistant fibers such as asbestos, rock wool, ceramic fibers, and slag wool are used, and one made of one or more heat-resistant and heat-insulating fibers is preferably used. Those made of fine fibers are heat insulating,
It is desirable in terms of sound deadening and vibration absorption. The production of such a fiber mat is performed, for example, by impregnating a heat-resistant fiber nonwoven fabric with a heat-resistant adhesive such as an alkali metal silicate-based inorganic adhesive, a phosphate-based inorganic adhesive, or an alkyl silicate-based inorganic adhesive. It can also be done by stacking, and it has a lower melting point than the heat resistant fibers used such as aluminum powder, calcium powder, lead powder, barium powder, sodium chloride, calcium chloride, and the temperature that the exhaust pipe system reaches during actual operation. Liquid adhesive containing substances that melt at higher temperatures or coupling agents such as silane coupling agents, titanium coupling agents, and aluminum-based coupling agents are impregnated into the heat-resistant fiber nonwoven fabric and laminated. The formed mat is heat-treated to melt or bake the substance, and then cooled and solidified to form a mat with heat-resistant fibers bonded to the substance. It can also be carried out by the.
The fiber mat may also contain suitable amounts of heat-expanding agents such as vermiculite, expandable mica, expandable graphite, perlite and the like, for example 1 to 100 parts by weight per 100 parts by weight of the heat-resistant fibers. In the case of commercial products, for example, "Interram Mat"
(Product name, manufactured by 3M Company, USA) can be given as a specific example of the fiber mat.

The enclosing member of the present invention is for enclosing an exhaust pipe system of an internal combustion engine such as an automobile engine. That is, for example, as shown in FIG. 2, it surrounds the exhaust pipe system including the dual front pipe 5, the catalytic converter 6, the tail pipe 7, the muffler 8, and the like. The surrounding method may be a method of winding the surrounding member of the present invention (hereinafter also referred to as a laminated body) around the exhaust pipe system as shown in FIG. A method in which a frame having such a shape is fixed to the outer shape of the exhaust pipe system in the lengthwise direction, and the laminate is wrapped and fixed to the exhaust pipe system via this frame, or an exhaust pipe using two laminates with the frame fixed A method of enclosing and fixing the system from above and below or from the left and right can be exemplified.

In the example of FIG. 2, the laminate is wound around the outer circumference of the inner pipe of the double pipe structure tail pipe. The wrapping method using the winding method has an advantage that it can be advantageously applied to a narrow space.

The application of the enclosing member of the present invention to the exhaust pipe system may be a combination of an outer peripheral envelope and an inner envelope, as shown in FIG. 2, or the whole not including the inner envelope may be an outer envelope. Good. Further, the exhaust pipe system may be surrounded without any gap, or may be surrounded with an appropriate gap.

EFFECTS OF THE INVENTION The exhaust stack surrounding member of the present invention is easy to manufacture and excellent in mass productivity, and its fiber mat is reinforced and supported by the surrounding braided mesh and has excellent resistance in mechanical properties such as vibration resistance. In addition to maintaining heat insulation, sound deadening, and vibration absorption functions for a long period of time, the fiber mat front and back (upper and lower) when the exhaust pipe system is enclosed
One of the braided meshes is interposed between the exhaust pipe system and the fiber mat to form an air layer, and this air layer also exhibits a heat insulating function. Therefore, based on the above-mentioned heat insulation function by the fiber mat and the air layer, the sound deadening function and the vibration absorption function by the fiber mat, the catalytic converter is maintained at a high temperature and exerts a high purification capacity and is adjacent to the exhaust pipe system. The equipment and devices are protected from high heat (insulation function) and the risk of fire is effectively avoided. Further, noise caused by vibration of the exhaust pipe system is also reduced (silence-reducing function and vibration-absorbing function).

Application example Application example A flat metal wire mesh formed by knitting stainless wire with a diameter of 0.25 mm is flattened, and a fiber mat made of ceramic paper with a thickness of 2.0 mm is inserted into it and compressed through a compression roll. A flattening process was performed to obtain a laminate.

Next, the laminate was wrapped around an exhaust pipe system attached to an automobile engine with a displacement of 1500 cc without gap to surround the exhaust pipe system. This exhaust pipe system has dual front pipes, diameter
10cm, length 20cm, passing air volume (pressure difference: 276mm water column) 4000
/ Min It consists of a catalytic converter with a built-in ceramic honeycomb catalyst, a tail pipe and a muffler, and the surrounding is a dual front pipe, the outer circumference enclosing method for the catalytic converter and the muffler, and the inner pipe for the double tail pipe. It was performed by a method of surrounding only the outer periphery of the.

Then, the engine with the exhaust pipe system in the above-mentioned enclosed state was operated, and the temperature distribution and noise distribution of the exhaust pipe system after 5 minutes, 15 minutes, and 30 minutes after the engine became in the steady operation state. I checked. The temperature distribution was measured on the surface of the object to be measured, and the noise distribution was measured at the center point of the components of the exhaust pipe system at a position 1 cm away from the object to be measured. The results are shown in the table.

Comparative Example 1 The temperature distribution and noise distribution under engine operation were examined in the same manner as in the application example except that the exhaust pipe system was used as it was without surrounding treatment. The results are shown in the table. The temperature of the outer wall of the catalytic converter is 150 ℃ (after 5 minutes), 300 ℃ (after 15 minutes), 400 ℃.
It was ℃ (after 30 minutes).

Comparative Example 2 A temperature distribution under engine operation was performed in the same manner as in the application example, except that a flat plate of a wire mesh obtained by compressing and flattening a flat metal mesh was used without inserting a ceramic fiber mat. The noise distribution was investigated. The results are shown in the table.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of an application example of an enclosure member of the present invention to an exhaust pipe system. 1: Laminate 2: Wire mesh 3: Fiber mat 5: Dual front pipe 6: Catalytic converter 7: Tail pipe 8: Muffler

Front Page Continuation (72) Inventor Akimasa Sugiyama 8 Nishinomachi, Higashimukaijima, Amagasaki City, Hyogo, Dainichi Nippon Electric Cable Co., Ltd. (56) Reference JP-A-55-64113 (JP, A)

Claims (1)

[Claims] 1. A braided mesh above and below a fiber mat in a compression-flattened fiber mat with holes interspersed in a cylindrical braided mesh and spot welded through the holes of the fiber mat. An exhaust pipe enclosing member for enclosing an exhaust pipe system of an internal combustion engine.