JPS5838313A - Heat shielding panel for catalyst converter - Google Patents

Abstract

PURPOSE:To prevent the production of vibration noise at a catalyst heat shielding panel, by mounting a porous substance, having pores whose hole area percentage is set to a given value, to an opening formed in a part of the heat shielding panel. CONSTITUTION:An opening is provided in a center of a heat shieling panel 12 covering the periphery of a catalyst receptacle, and a porous panel 11, in which pores 11a are evenly distributed so that a pore area percentage is set to 7-30%, is secured to said part. The porous panel 11 has a high sound absorbing effect and a low sound radiating effect, and this permits the reduction of vibration noise produced from the entire heat shielding panel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot plate of a catalytic converter installed in an automatic direct exhaust passage.

For example, the heat shield plate of a conventional catalytic converter and the first
There is something like the one shown in the figure (Nissan Automatic Turtle - Skyline Service xF4 Report No. 586, published in July 1978). In the same figure, l is the heat shield body made of press-formed sheet metal,
This VC is water drain hole 2, this heat shield body! A running bolt hole 3 and a mounting recess 4 for attaching the converter to the converter are formed respectively.The heat shield plate of such a catalytic converter is made of thin I sheet metal with drainage holes to drain water and prevent contact with dry grass. Most likely, due to the vibrations during engine operation and the resonance of the exhaust pipe, the heat shield that covers the outer part of the catalytic converter will also resonate due to the vibrations, and this will become noise and radiate to the outside. 91 Honsha #4 is an attempt to solve this conventional problem, and by providing a porous vibration energy absorption part in a part of the heat shield plate, the heat shield plate itself is The present invention provides a heat shield plate for a catalytic converter that suppresses the vibrations of the heat shield plate, thereby effectively preventing the generation of vibration noise from the heat shield plate.

Embodiments of the present invention will be described below with reference to the drawings. Figure 2 shows an exploded view of the heat shield plate of the present invention. 611 is a perforated plate that absorbs vibration energy, and has a large number of small holes 111. is perforated and acts as an absorber of vibrational energy. 12 is the hot plate body made by press forming sheet metal,
An opening U is provided in the center of this main body 12, and this opening 13
The periphery of the perforated plate 11 is spot-contacted with the surrounding area f.
@6 They are fixed together as shown in Figure 6. 14 is a mounting bolt hole.

The perforated plate 11 and the heat-transmitting plate main body 12 are formed of an aluminum ζ-plated steel plate, a galvanized steel plate, etc., and the area of the perforated plate 11 is approximately 22 square meters of the projected area of the heat shield main body opening. For example, as shown enlarged in Figure 4, the hole pitch P is about 1 to 10 mm, and the closest hole has a diameter of 1 to 4 mm. The angle θ made by the straight line connecting the five small holes 11a is 30~
Note that 15 is the mounting clearance. Also, if twelve or more perforated plates 11F are stacked one on top of the other and attached to the apertures 13, it is possible to do so.

Next, we will explain the action.

Vibrations 1 from the vehicle body or exhaust system tubes are input to the heat shield body 12 through mounting parts such as the mounting bolt holes 14.The vibration energy Q is divided into the vibration energy Qs applied to the perforated plate 11 and the heat shield body 12. It is the sum of the vibrational energy Q applied to 12 (Q = Q, + Q,).

The noise outside the vehicle is the radiant energy of the entire heat shield plate, and if the radiant energy is 't-R, then R=η・Q.OHere,
is the radiation efficiency and Q is the vibrational energy □ Therefore, B=R++R-η, Q, +η, Q society (addition 1
2 represents the perforated plate, and 2 represents the heat-transmitting plate body).

However, since the perforated plate 11 has a high sound absorption efficiency and a small radiation efficiency η, the radiant energy B is smaller than the conventional heat-transmitting plate main body l which is an integral press even if the external input vibration energy Q is the same.

Also, since the perforated plate 11 is formed separately from the heat exchanger body, the number and size of the small holes 11 m in the perforated plate 11 can be arbitrarily selected, and the noise absorption of catalytic converters with different maneuverability is possible. FIG. 5 shows another embodiment of the present invention.

Instead of using a thin perforated plate 11 as a vibration energy absorbing part, a wire mesh 16 made of fine mesh stainless steel is installed. Figures 6 and 7 show the sound insulation effect (dB) i and the pore area ratio ((opening area/target area) x 100 inches) in the heat shield plate shown in Figure 6. This is a characteristic graph obtained from experiments to determine the relationship between heat shielding effects.The diameter of the small hole 11 is 1 mm, 2 mm, 5 mm, 4 mm, and 5 mm, and the pore area ratio is 7 mm or more. It has been confirmed that the sound insulation effect is excellent when the pore area ratio is 60 or less, and the heat insulation effect is also excellent when the pore area ratio is 6096 or less.

As explained above, according to the present invention, an opening is provided in a part of the heat shield body made by press-forming a sheet metal, and small holes with a hole area ratio of 7 to 50 cm are formed so as to close the opening. By integrally attaching the perforated plate with uniformly dispersed heat shielding plate, it is possible to effectively reduce the level of radiated noise emitted from the entire heat shield plate. Te.

By using a perforated plate, the overall burden can be reduced.

[Brief explanation of the drawing]

Figure 1 is a rapid heat plate of a conventional catalytic converter, Figure 2 is an exploded perspective view of the heat shield plate of the present invention, Figure 3 is a perspective view of the same after assembly, and Figure 4 is a planar RFJ diagram of the perforated plate. , FIG. 5 is a perspective view showing another embodiment, and FIGS. 6 and 1117 are graphs showing the sound insulation effect and heat insulation effect characteristics with respect to the pore area ratio of the perforated plate. 11... Perforated plate, 111... Small holes, 12... Heat shield plate main body, ■No.■ Fig. 2

Claims (1)

[Claims] In the heat shield plate of a catalytic converter connected to the exhaust system of an automatic military engine, an opening is provided in a part of the heat shield body made by press forming sheet metal, and the pore area ratio is A heat shield plate for a catalytic converter, which is made by attaching a perforated plate or wire mesh with 7 to 50% of small holes evenly distributed.