US2760592A - Tuning tube arrangement for combination air cleaner and intake silencer - Google Patents

Description

Aug. 28, 1956 F. SEBOK 2,760,592 TUNING TUBE ARRANGEMENT FOR COMBINATION AIR CLEANER AND INTAKE SILENCER Filed April 29, 1952 F ql 12-11 5 TIZ ET" Fran/r Sebok United States Patent TUNING TUBE ARRANGEMENT FOR COlVlBINA- TION AIR CLEANER AND INTAKE SILENCER Frank Sebok, Detroit, Mich., assignor to Houdaille Industries, Inc., a corporation of Michigan Application April 29, 1952, Serial No. 284,903

4 Claims. (Cl. 181--35) This invention relates to improvements in a tuning tube arrangement for a combination air cleaner and intake silencer, and also to a new and novel method of manufacturing such a unit, the invention being highly desirable for use in connection with air cleaning and intake silencing units for association with the carburetor of an internal combustion engine, but the invention will have other uses and purposes as will be apparent to one skilled in the art.

In the past, much difliculty has been experienced in the manufacture of intake silencers for use with the carburetors of internal combustion engines, and particularly in the manufacture of combination units comprising both air cleansing and intake silencing means. It is known that the object of an intake silencer is to attenuate the predominant tone emanating from the intake I manifold of the engine, commonly referred to as power roar. That predominating tone is usually of a relatively low frequency or long wave length, and therefore requires an attenuating or resonator chamber of comparatively large volume. Some of the previously experienced difiiculty resided in providing a combination air cleaning and intake silencing unit wherein the silencer had an attenuating chamber of sufficient size, and still making the unit small enough to fit properly beneath the hood of an automobile.

But another difliculty has been experienced which adds tremendously to the cost of a silencer for a cleaning and silencing unit. That is due to the fact that whenever a change is made in an automobile engine, or wherever two different automobile companies are manufacturing engines of substantially the same character and horsepower, a silencer has to be developed and designed for each particular engine. Such results in a tremendous expenditure for dies and other manufacturing equipment in order to make a silencer for each engine.

The instant invention seeks to overcome the aforesaid major difiiculty in the provision of a combinationair cleaning and intake silencing unit, embodying a simple structure associated with the silencing chamber for the fundamental engine tone, which may be easily and economically varied to conform the particular unit to the fundamental tone frequency of a number of engines of different make or possessing different variations.

A further object of this invention resides in the provision of an intake silencing arrangement having a readily and economically adjustable tuning tube associated with the attenuating chamber for the fundamental engine tone, whereby the particular silencer may be economically and readily adapted for use with a variety of different engines which come within the frequency range of the resonator and the tuning tube.

Still another object of the invention resides in the provision of an intake silencing arrangement embodying a pair of spaced concentric tubes with the space therebetween leading to an attenuating chamber, and a tuning tube also concentric with but spaced from each of the other tubes disposed therebetween, and secured to one of the other tubes, such tuning tube varying the sound wave length which the chamber alone would attenuate.

A further feature of the invention resides in the provision of a new and novel method of manufacturing an air cleaner and silencing unit and controlling the effective volume of an attenuating chamber of predetermined fixed size.

While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawings, in which- Figure l is a bottom plan view of a combination air cleaning and intake silencing unit, embodying principles of the instant invention; and

Figure 2 is an enlarged, part elevational and part vertical sectional view of the structure of Fig. 1.

As shown on the drawings:

In the illustrated embodiment of the instant invention, there is disclosed a casing, generally indicated by numeral 1, which may be fabricated from an upper shell 2 having a cylindrical side wall portion and an inwardly extending top portion shaped to define an annular filter supporting shoulder 3 and an inwardly and upwardly extending dome-like portion 4. This upper shell may be loc'loseamed as indicated at 5 to a lower bottom shell 6 having a cylindrical side wall and an inwardly extending bottom wall. Inside the casing is an upper partition 7 spot welded or equivalently secured to the underside of the shell 2 adjacent the shoulder 3 and which is preferably downwardly dished to define an attenuating chamber 8 between itself and the dome-like portion 4. The inner end of the partition 7 is turned downwardly and secured to an outlet conduit 9 for clean air. The inner end of the partition 7 is spaced from the termination of the dome-like wall portion 4 to provide an entrance as at 10 to the chamber 8.

Below the partition 7 is another partition 11 secured to the outer cylindrical portion of the bottom shell, and at its inner end is upturned, as is the bottom, and both these portions are secured to a tube or conduit 12. concentric with the outlet conduit 9 but of greater diameter to provide a space therebetween. The conduit 12 extends downwardly below the conduit 9 for engagement over the air intake horn of a carburetor, not shown in the drawings. This engagement is made positive by means of a clamping element 13 secured therearound as best seen in Fig. 1, the free ends of the clamping element being expanded or contracted by means of a bolt and nut arrangement 14.

It will be noted that the conduit 12 terminates short of the partition 7 to provide an entrance opening therebetween into a comparatively large attenuating chamber 15 having sufficient volume to nullify the predominant engine tone. Between the partition 11 and the bottom 6 is a third attenuating chamber 16 having a less volume than the chamber 15, but a greater volume than the chamber 8. Entrance into this attenuating chamber is had by means of one or more apertures 17 in the conduit 12.

In all cases, three attenuating chambers, each attuned I for the neutralizing ofa sound of different wave length than the'othcrs, may not in ali circumstances necessary. In some instances, only one relatively large chamber is utilized, and that of course is designed to nullify the fundamental engine tone.

On top of the shoulder 3 an annular filter element 18 is seated, such element usually comprising concentric rings or cylinders of screen material, with filter mass such as wavy wire, curled cattle tail hair, or other suitable substance, disposed therebetween. This filter element is held in position by means of a cover 19 shaped to seat against the upper portion of the element, the cover being held in position by a lock nut 20 engaged over the upper end of a bolt 21 indicated by dotted lines in Fig. 1 with the lower end secured to a transversely extending 2 bar 22 mounted in the outlet conduit 9. Inside the cover is a pad silencer 23 held in place by spider 24, such silencer being commonly referred to as a hiss silencer to attenuate by absorption a relatively mild hissing noise emanating from an engine. Secured to the upper shell 2 around the filter element 18, but spaced therefrom on and, in the illustrated instance, is secured to the inside of the conduit 12 by spot welding or in an equivalent manner. The tube consequently defines an entrance passage into the large attenuating chamber 15 as indicated at 28, between itself and the outlet conduit 9. Obviously, the tube thereby affects the effective volume of the chamber. By lengthening this tube to the point indicated by dotted lines at 29, the effective volume of the chamber may be increased so that it will be capable of attenuating a longer sound wave or lower tone; while shortening the tube, n such for example as to the dashed line 30, will lessen the volume of the chamber, and adjust it for a fundamental tone of slightly higher pitch or shorter wave length. Thus, by merely varying the length of the tuning tube 26, the attenuating chamber 15 may be adjusted to a reasonable frequency range so that the intake silencer may be used with a variety of different engines having fundamental tones coming within that frequency range. The use of the tube 26 is simple and economical, and the use of that tube in many cases avoids the replacement of expensive dies and other equipment to manufacture the body portion of the unit housing the chamber 15. Manufacture of the unit within the frequency range controlled by the tuning tube 26 is therefore economical to an extreme degree, because new designs for each variation in respective engines are eliminated.

It will also be noted that this tuning tube may be varied in diameter, if desired, and a combination of variances in diameter and length increases the frequency range for which the chamber 15 may be adjusted.

In operation, with the conduit 12 connected to the intake horn of a carburetor, air is drawn through the filter element 18 by suction from the engine, over the dome-like portion 4 of the shell 2, and down through the outlet conduit 9 into the carburetor. At the same time, sound waves emanating in the intake manifold of the engine pass backwardly, and those of the fundamental tone of the engine will enter the chamber 15 through the space 28 where they are neutralized on the resonator principle. With the illustrated structure sound Waves considerably less in wave length will also be neutralized in the chamber 16, while still higher pitched sounds will be neutralized in the chamber 8, and the hiss of the engine will be absorbed by the hiss pad 23.

From the foregoing, it is believed my novel method of controlling the effective volume of an attenuating chamher is sufficiently clear as to warrant no further description herein.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

1 claim as my invention:

1. In an intake silencer structure, a casing having an inlet, an outlet conduit leading from the interior of said casing, said casing having a sound attenuating chamber therein, a conduit concentric with but of larger diameter than said outlet conduit forming the inner wall of said chamber and arranged to provide an opening into said chamber from the space between said conduits, and a tuning tube with an ofiset upper margin secured to one of said conduits adjacent said opening, said tube extending a predetermined distance between said conduits to adjust said attenuating chamber for a particular sound wave by providing a passage between itself and one of said conduits of less size than the space between the conduits.

2. In an intake silencer structure, a casing having an inlet, an outlet conduit leading from the interior of said casing, said casing having a sound attenuating chamber therein, a conduit concentric with but of larger diameter than said outlet conduit forming the inner Wall of said chamber and arranged to provide an opening into said chamber from the space between said conduits, and a tuning tube disposed between and concentrically with said conduits, said tube having an enlarged upper end secured to the second said conduit adjacent said opening, said tube forming an extension of said attenuating chamber of predetermined length.

3. in an intake silencer unit embodying a casing having an inlet, a sound attenuating chamber, an outlet arrangement comprising three concentric but spaced tubes, the inner tube forming an outlet conduit for air, the outer tube being the longest for connection with an air intake horn and defining a wall of the attenuating chamber, said outer tube being arranged to provide an opening into said attenuating chamber from the space between the inner and outer tubes, and the middle tube being disposed substantially centrally between the other tubes and having an expanded upper end secured to the outer tube adjacent said opening, said middle tube forming in effect an extension of said attenuating chamber.

4. In an intake silencer unit embodying a casing having an inlet, a sound attenuating chamber, an outlet arrangement comprising three concentric but spaced tubes, the inner tube forming an outlet conduit for air, the outer tube being the longest for connection with an air intake horn and defining a wall of the attenuating chamber, said outer tube being arranged to provide an opening into said attenuating chamber from the space between the inner and outer tubes, and the middle tube having an olfset upper end connected to one of the other tubes to restrict said opening a predetermined extent.

References Cited in the file of this patent UNITED STATES PATENTS 728,200 Butler May 19, 1903 2,149,836 Brown Mar. 7, 1939 2,325,352 Wilson July 27, 1943 2,385,814 Kamrath Oct. 2, 1945 2,557,236 Sebok June 19, 195i

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