JPS5941073B2 - flexible connecting pipe - Google Patents

Description

[Detailed Description of the Invention] Automobiles usually mainly use an internal combustion engine as a power source,
It goes without saying that it is necessary to allow the generated exhaust gas to quietly escape to the atmosphere from the rear of the vehicle body through a so-called exhaust system such as an exhaust pipe under the floor of the vehicle body and a muffler (including an exhaust purification device 4 if necessary). However, it is necessary to satisfy at least two other points.

The first is to prevent the exhaust gas from leaking outside from the middle of the exhaust system, and the second is that the internal combustion engine vibrates during operation, so the exhaust system that is fixedly connected to it must be made sturdy with a hanging fitting 6 etc. with rubber or the like interposed. In addition, it is required to hang it loosely on the chassis so that vibrations are not transmitted to the chassis, and also to allow its own vibration so that it does not break.

In the automobile exhaust system of the present invention, after the exhaust manifold pipe 2, a new double metal helical flexible pipe 11 and
2 is arranged, a pressure air layer 19 is created between both spiral flexible tubes (hereinafter abbreviated as "spiral tube"), and pressurized air is introduced.
The inner spiral pipe 11 is connected to the flexible connecting pipe 10, which serves as an exhaust gas passage and is airtightly connected to the exhaust pipe 3, and is tightly fixed to the chassis 7 via a mounting bracket 8 covered with asbestos or the like. absorbs all the vibrations to the exhaust system, and also directs the high-temperature exhaust gas passing through the inner spiral pipe 11 constituting the flexible connecting pipe 10 to the outside of the pipe by the pressure of the compressed air in the pressure air layer 19 outside the pipe. It is an object of the present invention to provide an exhaust system including a flexible connecting pipe 10 which serves both the purpose of preventing leakage and overheating itself by air, ensuring functionality and safety.

To explain the drawings now, FIG. 1 is a schematic external view of an exhaust system equipped with a flexible connecting pipe 10 of the present invention.

Exhaust gas discharged from the internal combustion engine 1 passes through the exhaust manifold pipe 2, the flexible connecting pipe 10 of the present invention, the exhaust pipe 3, the muffler 5, etc., and escapes to the outside air from the rear end.

As mentioned above, the flexible connecting pipe 10 absorbs vibrations to the vehicle body, and the exhaust gas escapes to the atmosphere without leaking outside the pipe.

FIG. 2 shows details of an example of the flexible connecting tube 10 of the present invention.

There are various types of spiral tubes, but metal spiral flexible tubes are preferred due to their flexibility, workability, durability, heat resistance, and low cost.

The inner spiral pipe 11 is fixedly welded to the flange 13 in an airtight manner,
The outer helical tube 12 is further inserted to the outer side via this outer spacing shaft 15 and is tightened and welded with a band 14.

A pressure air layer 19 is formed between the inner and outer helical tubes 11,12.

In addition, air passage holes and grooves 16, 17 and 18 are perforated through the flange 13 and the spacing shaft 15, respectively, and pressurized air is introduced into the compressed air layer 19 through an air pipe 20 from an air pump 21 attached to the engine. .

On the opposite outlet side of the flexible connecting pipe 10, similar to the inlet side, air passage holes and grooves 16, 17, 18, etc. are bored and cut using the same flange 13, band 14 and spacing shaft 15.

Unlike the front inlet side, an air outlet pipe 22 with a valve 23 is provided so that the passage area can be varied, and the air pressure in the compressed air layer 19 can be maintained appropriately by using a base.

When the entire engine operates, exhaust gas flows from the exhaust manifold pipe 2 into the inner spiral pipe 11 and flows out into the exhaust pipe 3. At the same time, the air pump 21 attached to the engine operates, and pressurized air flows into the pressure air layer 19. I'm coming.

The exhaust gas pressure in the inner spiral pipe 11 is Pl, the air pressure in the pressure air layer 19 is P2, and P.

When ≦P2, even if the inner spiral pipe 11 loses some degree of airtightness, the exhaust gas will not leak.

We would like to recognize that in order to improve the performance of automobiles, we are constantly working to reduce exhaust pressure and increase engine horsepower.

In fact, although there are large differences between cars, the exhaust pressure near the flexible connecting pipe 10 is about 0.5 atm above atmospheric pressure.
The air pressure of the air pump 21 is considered to be about 1 atm above atmospheric pressure, and furthermore, the pressure of pressurized air is high and the amount used is small.
Also, it is necessary to take into account that although the pressure of exhaust gas is low, the amount is large.

If necessary, the outer helical tube 12 may be wrapped with asbestos paper or the like in layers during the process of forming the helical tube metal strip.

As described above, the present invention relates to a flexible connecting pipe 1 interposed between an exhaust manifold pipe 2 of an engine and an exhaust pipe in an automobile exhaust system.
0, which absorbs engine vibrations, prevents high-temperature exhaust gas from leaking to the outside, and prevents overheating of the engine itself, ensuring functionality and safety. This has a very effective function and effect in that it eliminates the need for a special hanging fitting 6 that is prone to breakage, and prevents vibrations of the engine from being applied to the automobile body.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the overall appearance of an automobile exhaust system equipped with a flexible connecting pipe according to an example of the present invention. FIG. 2 is a central cut section and an external view of a flexible connecting pipe according to an example of the present invention. FIG. 3 shows an overall schematic diagram of an example of a conventional exhaust system for a general automobile.

Claims (1)

[Claims] 1 Create a pressure air layer between the inner and outer helical flexible tubes arranged in a double concentric manner, introduce pressurized air into this layer, and maintain the pressure equal to or higher than the pressure of the exhaust gas passing through the inner helical flexible tube. A flexible connecting pipe for an automobile exhaust system in which this is interposed between an internal combustion engine and an exhaust pipe.