US3605940A - Exhaust header system - Google Patents

Abstract

THE EXHAUST HEADER SYSTEM IS FOR USE WITH AN INTERNAL COMBUSTION ENGINE, AS FOR INSTANCE WITH THE PORSCHE 911, WHEREIN THE CYLINDERS ARE DIVIDED INTO TWO EXHAUST BANKS. THE SYSTEM COMPRISES A MUFFLER WHICH IS CONNECTED TO EXHAUST CONDUITS FROM THE RESPECTIVE CYLINDER BANKS, WHICH CONDUITS ARE ADAPTED TO PROVIDE SUBSTANTIALLY THE SAME RESISTANCE TO THE FLOW OF EXHAUST GASES THERETHROUGH. NOTWITHSTANDING THE FACT THAT ONE SUCH CONDUIT IS LONGER THAN THE OTHER, THE RESISTANCE IS MAINTAINED SUBSTANTIALLY EQUAL BY VIRTUE OF THE ADDITION OF CERTAIN TURNS OR BENDS IN THE SHORTER ONE. THE MUFFLER IS UNIQUE IN HAVING COAXIALLY ARRANGED INNER AND OUTER TUBULAR MEMBERS AND NOISE ABSORBING MEANS INTERPOSED THEREBETWEEN. THE INNER TUBULAR MEMBER IS PERFORATED BUT THE SEVERAL TUBULAR MEMBERS ARE MAINTAINED STRAIGHT SO THAT THE FLOW OF EXHAUST GASES IS UNIMPEDED AND THE NOISE IS ABSORBED BY THE NOISE ABSORBING MEANS BETWEEN THE TUBULAR MEMBERS.

Description

p 20, 1971 w. A. CHRISTENSEN 3,605,940

EXHAUST HEADER SYSTEM Filed May 12, 1969 O O O O O O O O 0 000000000 INVENTOR. WAY/ve- A. Gueurewsew BY wwfw/ Irma/vans United States Patent 3,605,940 EXHAUST HEADER SYSTEM Wayne A. Christensen, 1959 Harbor Blvd., Costa Mesa, Calif. 92627 Filed May 12, 1969, Ser. No. 823,927 Int. Cl. F01n 1/04; F02b 27/00 US. Cl. 18142 5 Claims ABSTRACT OF THE DISCLOSURE The exhaust header system is for use with an internal combustion engine, as for instance with the Porsche 911, wherein the cylinders are divided into two exhaust banks.

The system comprises a muffler which is connected to exhaust conduits from the respective cylinder banks, which conduits are adapted to provide substantially the same resistance to the flow of exhaust gases therethrough. I

Notwithstanding the fact that one such conduit is longer than the other, the resistance is maintained substantially equal by virtue of the addition of certain turns or bends in the shorter one.

The mufiler is unique in having coaxially arranged inner and outer tubular members and noise absorbing means interposed therebetween. The inner tubular member is perforated but the several tubular members are maintained straight so that the flow of exhaust gases is unimpeded and the noise is absorbed by the noise absorbing means between the tubular members.

The present invention relates generally to exhaust header systems and more particularly to such systems as used on internal combustion engines wherein the cylinders are divided into several banks.

For various reasons, certain internal combustion automobile engines have their cylinders divided into several banks. This is particularly true of engines such as are used on the Porsche 911 wherein the six cylinders are divided into two banks of three cylinders each.

Such banks are desirable from various standpoints, not the least of which is for the sake of overall efficiency and balanced operation.

Heretofore, exhaust systems have been provided for such dual-bank engines but such systems have been incapable of affording maximum efficiency for the engine and minimum external noise. That is, prior exhaust systems have been unbalanced so that considerably more back pressure was created for one bank of cylinders than for the other. Also, the mufilers of such prior systems have been so constructed that the maximum noise level could not be maintained without subjecting the engine to undue exhaust pressures and inefliciencies.

It is an object of the present invention to provide an exhaust system for internal combustion engines which have their cylinders divided into several cylinder banks, wherein the exhaust flow resistance or back pressure is substantially equal for the several cylinder banks.

Another object of the present invetnion is to provide an exhaust header system as characterized above which comprises a single muffier and two exhaust conduits of different lengths, such conduits being individually constructed and adapted so that in spite of different lengths and shapes the back pressure and exhaust flow resistance therein are substantially equal.

3,605,940 Patented Sept. 20, 1971 An object of the present invention is to provide an exhaust header system as characterized above wherein the longer exhaust conduit has fewer bends than the shorter one so that the overall flow resistance in such conduits is substantially equal.

Another object of the present invention is to provide an exhaust header system as characterized above which comprises a muffler of the straight-through type having an inner tubular member which is perforated and an outer tubular member, there being noise absorbing means interposed between such tubular members.

A still further object of the present invention is to provide an exhaust header system as characterized above wherein the noise absorbing means in the mufiler is cutcreole glas.

An even further object of the present invention is to provide an exhaust header system as characterized above which is simple and inexpensive to manufacture and which is rugged and dependable in operation.

The novel features which I consider characteristic of my invention are set forth with particularity in the appended claims. The device itself, however, both as to its organization and mode of operation, together with addi tional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of an exhaust header system according to the present invention;

FIG. 2 is a top plan view of the system of FIG. 1;

FIG. 3 is a fragmentary sectional view through the muffer of the system; and

FIG. 4 is a transverse cross-sectional view of the muffler.

Like reference characters indicate corersponding parts throughout the several views of the drawings.

Referring to FIG. 1 of the drawings, there is shown therein an exhaust header system according to the present invention. It comprises a muffler 10 having an inlet 12 and an outlet 14. An exhaust pipe 16 one end of which is flared as at 16a is connected to the outlet 14 of muffler 10.

The system further comprises a pair of exhaust conduits 18 and 20 each of which is adapted for connection to a separate one of two cylinder banks of an internal combustion engine (not shown).

The subject invention is most suitable for use with those internal combustion engines which have their cylinders divided into several cylinder banks, and wherein overall efliciency and top performance is of prime importance. One such application of dual cylinder banks is found in the Porsche 911 which is a high performance automobile of the sport or racing type. Not only must the Porche 911 operate efficiently so that all of the energy of the fuel is converted into propulsion of the automobile, but the operation of the engine thereof must be balanced and steady.

The inlet end of conduit 18 is provided with a flange 22 formed of quarter inch steel plate. Such flange is provided with several mounting holes 24 as well as a through central opening, and is welded to the inlet of conduit 18 so that the through opening is axially aligned with the internal diameter of the conduit.

Although not mandatory for successful practice of the instant invention, conduit 18 is preferably constructed of two-inch outside diameter eighteen gauge rolled steel tubing. It is formed with three ninety degree bends as at 18a, 18b and 18c and is approximately forty-one inches in length. A support member 26 between mufiler and conduit 18 is Welded to such members at bend 18a to provide the desired rigidity and strength for the assembled unit.

Conduit is provided with a flange 28 formed of onequarter inch steel plate on the order of the aforedescribed flange 22. Flange 28 is provided with several mounting holes and has a central through opening aligned with the internal opening of conduit 20 when flange 28 is firmly welded to the end of said conduit. Conduit 20, it has been found, should be approximately thirtythree inches in length if the aforementioned conduit 18 is forty-one inches long, and the conduit 20 should have six bends, five of which are ninety degree bends and one of which is a forty-five degree bend. As shown most clearly in FIG. 2 of the drawings, the ninety degree bends are at 20a, 20b, 20c, 20d and 20e and the forty-five degree bend is at 20f adjacent the collector 32. As in the case of conduit 18, the conduit 20 may be constructed of twoinch outside diameter eighteen gauge rolled steel tubing, although the precise dimensions and sizes are not mandatory for successful practice of the instant invention.

The collector 32 is formed of 16 gauge seamed steel tubing and is so constructed as to accommodate both of the conduits 18 and 20 as shown most clearly in FIGS. 1 and 3 of the drawings. As shown in FIG. 3, the collector 32 provides conduit 18 with a relatively straight flow path into the mufller 10. The conduit 20, on the other hand, is brought into the muffler 10 at a forty-five degree angle thus causing the exhaust gases therefrom to create additional back pressure or resistance at the collector 32 within conduit 20.

The entire assembly is weld together, the flanges 22 and 28 being welded securely to the ends of conduits 18 and 20, respectively. The conduits are also firmly welded to the collector 32 as shown at 34. The collector, in turn, is welded to the mufller 10 as shown at 36.

As shown most clearly in FIGS. 3 and 4 of the drawings, the muffler 10 is formed with coaxially arranged inner and outer tubular members 38 and 40. Such members are preferably circular in cross-section as shown most clearly in FIG. 4 of the drawings.

The inner tubular member 38 is perforated as shown at 38a, and noise absorbing material such as cut-creole glas 42 as positioned within the annular space between the tubular members 38 and 40. Although substantially any type of glass fibers can be used to absorb some or most of the noise normally encountered with engine exhaust, it has been found desirable to use cut-creole glas. This utilizes glass fibers which are not of continuous length, but rather are cut to certain lengths so as to be arranged at random with respect to each other. The cut glass is then soaked in a solution resembling creosote to render the same capable of absorbing noises. The name cut-creole glas is a well-known term in the manufacture of mufliers, and pertains to such short cut glass fibers which have been soaked in the particular solution that resembles creosote.

The outer tubularmember 40 is swedged at its opposite ends to a position adjacent the inner tubular member 38 and such members are then welded together as shown at 36 and 44. The welding operation at 44 also firmly and hermetically secures the pipe 16 to the outlet 14 of the muffler.

Although not mandatory for successful practice of the instant invention, it has been found desirable to construct the outer tubular member 40 of muffler 10 of sixteen gauge rolled steel having an outer diameter of approximately three and three-quarters inches, andto form the inner tubular member 38 of eighteen gauge perforated rolled and seam-welded steel having a diameter of two inches.

Exhaust pipe 16 is formed with a ninety degree bend as shown at 16b.

The subject exhaust header system is attached to the automobile such that the flanges 22 and 28 are connected to the engine at the several banks of cylinders respectively. For instance, in the Porche 911 wherein the six cylinders are divided into two banks of three cylinders each, the conduit 18, by means of the flange 22, is secured or connected to the engine at one such bank and the conduit 20, by means of the flange 28, is secured at the other. The fact that the several cylinder banks are on opposite sides of the engine and yet the several conduits 18 and 20 must come together at a single point in order to simultaneously feed into the common muffler 10, causes the conduits 18 and 20 to be of difierent lengths. Thus, the conduit 18, of necessity, is longer than the conduit20. However, by placing an additional three-hundredeighty degree loop in the conduit 20, the shorter length of the said conduit 20 is afforded additional flow resistance. That is, although the conduit '18 is longer and hence oifers more total resistance to exhaust flow therethrough, the conduit 20 is provided with additional ninety degree bends to compensate ,for the additional length of conduit 18.

It is thus seen that although the conduits are of difierent lengths, the flow resistance ofiered thereby is substantially equal thus rendering the exhaust system balanced.

The construction of the muffler 10, per se, is unique in that it is simple and yet effective. It will be noted that the exhaust gases are afforded a straight-through flow since the inner tubular member 38 is provided without any turns or bends. The unique noise absorbing material, cutcreole glas, causes the noise to be absorbed sufliciently without sacrificing any of the desirable results afforded by the straight-through flow. Such arrangement has been found preferable to the use of baflies wherein the exhaust gases are required to follow a complicated circuitous path.

The exhaust gases, of course, are emitted into the atmosphere through the pipe 16, the right angle bend 16a having no effect whatever on the balanced condition of the exhaust header system because it affects both banks of cylinders.

It is thus seen that the present invention provides a balanced exhaust header system wherein noise is sufficiently absorbed to maintain the exterior noise level below the prescribed maximum, and excessive unbalanced back pressures are not created for the internal combustion engine.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim:

1. Exhaust header system for internal combustion engines, comprising in combination, a muffler having an inlet, an outlet and noise mulfling means intermediate thereof, two exhaust conduits of identical cross-section but of different lengths and shapes and being individually adapted for connection with a separate one of several banks of cylinders of said engine, and a collector interposed between said muifier inlet and said conduits to cause said longer conduit to have substantially straight flow into said mufiler at the inlet thereof and said other conduit to cause the exhaust gases therein to make approximately a forty-five degree bend in direction of flow into said muffler to thereby cause the total resistanceto flow of exhaust gases in said conduits to be substantially identical. 7

2. Exhaust header system for internal combustion automobile engines according to claim 1, wherein said mufller is formed with coaxially arranged inner and outer tubular members and noise absorbing means is interposed therebetween.

3. Exhaust header system for internal combustion automobile engines according to claim 2, wherein said inner tubular member is formed with perforations to enable noise within said mufller to be absorbed by said noise absorbing means between said tubular members.

4. Exhaust header system for internal combustion automobile engines according to claim 3, wherein said noise absorbing means is heat resistant cut-creole glas to prevent burning of said muffier by hot exhaust gases.

5. Exhaust header system for internal combustion automobile engines according to claim 4, 'wherein said inner and outer tubular members are straight to afford minimum resistance to flow of exhaust gases therethrough.

References Cited UNITED STATES PATENTS STEPHEN J. TOMSKY, Primary Examiner US. Cl. X.R.

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