US2798470A

US2798470A - Air intake silencer chamber

Info

Publication number: US2798470A
Application number: US455681A
Authority: US
Inventors: Elmer C Kiekhaefer
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-09-13
Filing date: 1954-09-13
Publication date: 1957-07-09
Anticipated expiration: 1974-07-09

Description

July 9, 1957 E. C.,KIEKHAEFER AIR INTAKE SILENCER CHAMBER 2 Sheets-Sheet l File'd Sept. 15. 1954 -Il u m E FIG. l.

/M/ENTOR MMU? C. Mum/AMER ,5v/j; M

ATTORNEY July 9, 1957 E. c. KIEKHAEFER 2,798,470

AIR INTAKE SILENCER CHAMBER v Filed Sept. 15, 1954 2 Sheets-Sheet 2 By/a MM A TTOR/VEV United States Patent AIR INTAKE SILENCER 'CHAMBER Elmer C. Kiekhaefer, Cedarburg, Wis.

Application September 13, 1954, Serial No. 455,681 Claims. (Cl. 123-193.)

This invention relates generally to a noise silencer or muffler, and more specifically to .an air inlet silencer constructed integrally with the cowl of an internal combustion engine.

vIn the internal combustion engine, a mixture `of fuel and `air is drawn 'into the piston cylinders 'through :an intake valve that is alternately opened and closed. In engine operation, the sudden opening and closing of the intake valve, the moving stream of fuel `and air impinging against the valve in the closed position, and the throttling of the fuel-air mixture as it is drawn through the carburetor are actions resulting in the production of noise. Since the valve alternately opens and closes at a rapid rate, as often as one hundred times per second, the noise produced by the foregoing actions fis of considerable magnitude. Applicants invention resides in a `carburetor air inlet silencer constructed integrally with the cowl of an internal combustion engine for minimizing the production of noise resulting therefrom.

It is therefore an object of the present invention to provide an air inlet silencer constructed integrally with the cowl of an internal combustion engine to minimize the noise produced therein.

Another object of the invention is to provide an air inlet silencer `constructed integrally with the cowl of an internal combustion engine that is more economical, requires fewer parts of less complicated shape, and is easier to assemble than prior known silencers.

Another object of the invention is to provide an air inlet silencer for an internal combustion engine having a novel choke arrangement for varying the volume of air drawn into the carburetor thereof.

Objects and advantages other than those set forth above will be apparent from the following description when read in connection with the accompanying drawing, in which:

Fig. 1 is an elevation View in section of a fragmentary part of an outboard motor embodying the invention;

Fig. 2 is a section view taken along line 2 2 of Fig. 1;

Fig. 3 is an elevation view in section similar to Fig. l of another embodiment of the invention;

Fig. 4 is a section View taken along line 4-4 of Fig. 3; and;

Fig. 5 is an enlarged segmental View of the choke member shown in Figures l through 4.

As shown in Figures 1 and 2 of the drawings, a preferred embodiment of this invention is illustrated as applied to an internal combustion engine shown as a. power head 2 encased within a cowl 3 as embodied in an outboard motor, only a part of which is shown, having a segmental drive shaft housing 1 upon which the power head 2 is mounted. The cowl 3 has a lower part 4 in the form of a generally upwardly dished member mounted between the drive shaft housing 1 and the power head 2. The lower part 4 is provided with an annular iiange 6 along the top thereof. An upper part 7 of the cowl 3 forms a cover for the power head 2 and is also provided with an annular flange 8 along the BCC bottom thereof registering with the annular flange 6 of the lower part 4 and .mating therewith to enclose and .protect ythe power head 2. The lower part 4 is securely fastened to the upper part 7 by means yof studs 9. An opening 1'0 is formed by the lower part 4 of the cowl .3 rto admit air into the cowl for combustion purposes.

The vlower and upper parts 4, 7 of the cowl 3 are shown :as 'having adjacent lower pockets 11, 11' and

adjacent Vupper pockets

12, 12" respectively formed -integrally with the parts Zl, 7 by casting, welding, or any other suitable means. The lower pockets 11, 11' and

upper pockets

12, 12 each have a common portion shown as lower and

upper flanges

13, 14 respectively of generally 'semi-cirfcular cross section corresponding to the shape of the lower and upper parts 4, 7 and integrally formed therewith.

When Ithe upper part 7 isv joined to the .lower part 4, `the lower pockets 11, 11 and

upper pockets

12, 12

yregister respectively to define a silencer chamber 15 and a 'chamber 5 encasing the power head 2 with the flanges 1'3, 14 forming a wal-l common to both chambers 15, 5,. A v-seal 16, shown as an H-shaped grommet is provided to seal the

flanges

13, 14 so that there is no leakage at the junction thereof. The lower .pocket 11 ,further is provided with a conduit 20 extending outward from the lowermost point of the pocket 11 to convey liquids, such as gas that accumulates in the pocket 11 as a 'result of drippings and blow back from a carburetor 17, out of the pocket 11.

The chamber 15 yis further provided kwith a tubular member 18 dening an opening 19 having a diameter larger than the diameter of the air inlet y21 of the carburetor 17. The chamber 15 is positioned so that the member 18 surrounds the air inlet 21 providing a generally annular space between the peripheral surface of -the air inlet v21 and lthe inner periphery of the member 18. The annular space provides an opening through which l'combustion air is drawn into the chamber 15. The 'length of the tubular member 18 which is a function of the volume of the chamber 1S may be readily calculated by mathematical formulas which are well known in muiiier design calculations to provide a .silencing chamber having optimum muflling characteristics. The ltubular member 18 is shown `integral with the flange 13 of the' chamber 15, but may be fastened ito the flange 13 by any other suitable means. The inner peripheral surface of the member 18 is preferably inclined so that the liquid gas and gas vapor emitted from the carburetor 17 will not pass into the cowl 3, but will settle to the bottom of the chamber 15 and pass out of the chamber through conduit 20.

The lower part 4 of the cowl 3 forming a portion of the chamber l5 is provided with a boss 22 having a bore 23 therethrough. Outwardly of cowl 3 the boss 22 is provided with an elongated opening 24 transverse to the bore 23 and connected thereto. A resilient seal means 25 shown as a rubber washer is mounted on the face of the boss 22 within chamber 15 by any suitable means such as bonding. A choke member comprising a rod 26 is slidably disposed in the bore 23 and is provided with a plurality of spaced notches 27 over the length thereof. A knob 28 is provided on the end of rod 26 which extends outwardly of the cowl 3 whereby the rod may be manually actuated within the bore. The other end of rod 26 disposed within chamber 15 is provided with a disk 29 adapted to close off the air inlet 21 of carburetor 17. The disk 29 has a small opening 30 therein to permit air to be drawn into the carburetor 17 when the disk 29 closes off the air inlet 21. A spherical ball 31 and resilient means, shown as a spring 32, is interposed in the opening 24 and retained therein by means of a set screw 33. The spring 32 and ball 3l,

rprovided with an opening 34 which is adapted to receive the air inlet 21 of the carburetor 17 which is mounted on the power head 2. Seal means,.shown as a rubber grommet 35, is positioned around the air inlet 21 of the carburetor 17 to sealingly engage the ange 13 of the chamber 15 to prevent leakage of air into the chamber between theV air inlet 21 and the ange 13.

`At least one tubular member 36 extends through ange 14 and connects the chambers 15 and 5 of the engine cowl structure. Member 36 is provided with a. predetermined length which is a function of the volume of the chamber 15, and which may be readily calculated by mathematical formulas which are well kno-wn in muiiier design calculations to provide a silencing chamber having optimum muiing characteristics. The member 36 is shown fastened to the flange 14 by an annular U shaped seal 37 positioned around the periphery of the member 36.

Although only two embodiments have been illustrated and described, it will be apparent to those skilled in the art that other changes and modifications of the invention may be made without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an internal combustion engine having a carburetor mounted thereon provided with an air inlet, and a cowl encasing said engine, the combination of: adjacent chambers formed by said cowl with one of said chambers encasing said engine and carburetor and Vsaid other chamber forming a silencer, said other chamber having an opening therein in register with said carburetor air inlet so that air for carburetion is received Yfrom said other chamber and said other chamber further having means for admitting air therein.

2. In an internal combustion engine having a carburetor mounted thereon provided with an air inlet, and a cowl encasing said engine, the combination of:

adjacent chambers formed by said cowl and having a common wall, one of said chambers encasing said engine and said other chamber forming a. silencer, and said common wall having an opening therein in register with said air inlet, said opening further admitting air into said other chamber.

3. In an internal combustion engine having a carburetor mounted thereon provided with an air inlet and rst and second cowl members encasing said engine, the combination of: a rst plate member integrally formed with said iirst cowl member to define iirst adjacent pockets; a second plate member integrally formed with said second cowl member to define second adjacent pockets in register with said iirst adjacent pockets to form a silencer chamber and an adjacent chamber encasing said engine; one of said plate members being formed with an opening in register with said air inlet; and means provided in one of said plate members forming the silencer chamber for admitting air therein.

4. In an internal combustion engine having a carburetor mounted thereon provided with an air inlet, a cowl having one chamber for encasing said engine and a second adjacent chamber for enclosing said air inlet, said second chamber forming an air inlet silencer chamber and having an opening extending through the cowl in alignment with the air inlet, the combination of: actuating means slidably disposed in said opening in the cowl, and a member disposed within said silencer cham- -ber and mounted on said actuating means for engaging said air inlet to control the volume of air introduced into said carburetor.

5. In a cowl enclosed internal combustion engine provided with a carburetor having an air inlet, a wall provided within the cowl to divide the cowl enclosure into a lirst chamber, for encasing the engine and a second chamber, said wall having an opening therein for receiving the carburetor air inlet so that air for carburetion is received from said second chamber, and a tubular member entering the second chamber and providing for admission of air to said chamber, said tubular member having a predetermined length functionally related to the volume of the second chamber whereby optimum silencing of noise created by the movement of air to the carburetor is etected.

References Cited in the file of this patent UNITED STATES PATENTS y 1,761,221 Marx June 3, 1930 2,103,902 Heintz Dec. 28, 1937 2,224,900 Conover Dec. 17, 1940 2,256,831 Karey Sept. 13, 1941