US3497031A - Exhaust silencer - Google Patents

Description

Feb. 24, 1970 D. M. KEDZIORA EXHAUST SILENCER 2 Sheets-Sheet 1 Filed Feb. 4, 1969 w w 4 0 r w 6 2 8 I .q f w a 2 u U w w u m n a n 0 I 8 2 4 Q HQMQMQ 3 m F 2 0 a 4 9 f 2 Dennis M. K edziora INVENTOR.

BY Anomey:

Feb. 24; 1970 p. M. KEDZIORA EXHAUST SILENCER 2 Sheets-Sheet 2 Filed Feb. 4, 1969 Dennis M. Kea'ziora IN VENTOK.

U.S. Cl. 181-51 Claims ABSTRACT OF THE DISCLOSURE A first tubular airfoil-shaped extension for the outer end of the exhaust port of a small combustion engine and having longitudinally spaced outlet openings formed therein along the upper and lower camber areas thereof. The tubular member extends transversely through a second open-ended tubular member having generally parallel planar upper and lower sides opposing and spaced above and below the outer ends of the upper and lower outlet openings and the inlet end of the tubular member opens through a first side wall of the second tubular member connecting one pair of corresponding edge portions of the upper and lower sides while the outlet end of the first tubular member abuts and is closed by the other side wall of the second tubular member.

The exhaust silencer of the instant invention has been primarily designed for use in conjunction with two cycle model engines utilized to power high speed model planes, boats and cars, etc. However, it is to be noted that the silencer could also be utilized on larger engines, if desired.

The principle of operation of the exhaust silencer is that the exhaust gases from an associated engine are allowed to expand after passing outwardly of the exhaust port of the engine and are then passed through a plurality of small diameter apertures which open into venturi areas of low pressure. By utilizing venturi areas on the discharge side of the small diameter openings through which the exhaust gases are passed, movement of the exhaust gases through the small diameter openings or apertures without creating excessive back-pressures is accomplished. In addition, the exhaust silencer is largely constructed of sheet aluminum which dissipates heat readily and thereby further tends to reduce back-pressures. Also, the utilization of sheet aluminum in the construction of the exhaust silencer maintains its weight at a minimum and thereby does not materially increase the weight of the two cycle model engine with which it is associated. Finally, inasmuch as the silencer first allows the exhaust gases to expand and then causes the exhaust gases to pass through small diameter apertures into venturi areas of low pressure, the pitch of the sound of the exhaust is substantially altered from the sound of an unsilenced two cycle model engine so as to further add to the exhaust silencing characteristics of the exhaust silencer.

In addition to the above features of the exhaust silencer attributing to the silencing of the exhaust discharge from a two cycle model engine, exhaust back pressure is reduced by the exhaust being discharged into venturi areas of low vacuum and the associated two cycle model engine is capable of developing more power.

Still another important operating characteristic of the exhaust silencer is that its heat dissipating properties not only tend to reduce the temperature of the exhaust gases before they are finally discharged into the ambient atmosphere but the cylinder temperatures of the associated model engine are reduced whereby wear and tear on the engine is reduced by maintaining the lubrication properties thereof, and thereby reducing gum deposits and any tendency of seizure of relatively movable parts. Further,

a more dense charge is admitted into the cylinder during each intake interval thereby further increasing the power output of the model engine.

The main object of this invention is to provide a silencer which may be readily removably attached to substantially all model engines.

Another object of this invention is to provide an exhaust silencer in accordance with the preceding object and which will tend to reduce engine exhaust back pressure and thereby increase the power output of the associated model engine.

Yet another object of this invention is to provide an exhaust silencer having operating characteristics serving to reduce cylinder temperatures of the associated model engine and thereby further increase its power output.

Another very important object of this invention is to provide an exhaust silencer in accordance with the preceding objects and which will be of lightweight construction.

A final object of this invention to be specifically enumerated herein is to provide an exhaust silencer in accordance with the preceding objects which will conform to conventional forms of manufacture, be of simple construction and easy to install so as to provide a device that will be economically feasible, long lasting and relatively trouble-free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view of a conventional form of model engine with the exhaust silencer of the instant invention operatively associated therewith;

FIGURE 2 is an enlarged fragmentary vertical sectional view taken substantially upon the plane indicated by the section line 22 of FIGURE 1;

FIGURE 3 is a fragmentary enlarged horizontal sectional view taken substantially upon the plane indicated by the section line 33 of FIGURE 1;

FIGURE 4 is a fragmentary enlarged vertical sectional view taken substantially upon the plane indicated by the section line 44 of FIGURE 2; and

FIGURE 5 is an exploded perspective view of the exhaust silencer.

Referring now more specifically to the drawings, the numeral 10 generally designates a conventional form of two cycle model engine. The engine 10 includes a crankcase 12 on top of which a cylinder 14 is mounted. A crankshaft 16 is journaled through the crankcase 12 and a piston 18 is reciprocal in the cylinder 14 and connected to the crankshaft by means of a connecting rod 20. Also, a cylinder head 22 including a glow plug 24 is secured to and closes the upper end of the cylinder 14.

A carburetor inlet 26 opens downwardly into the portion of the crankcase 12 through which the crankshaft 16 is journaled and it is to be noted that the crankshaft 16 includes a hollow portion opening radially outwardly of the crankshaft 16 for registry with the inner end of the carburetor inlet and opening inwardly to the crankcase 12. Further, a by-pass passage 28 is formed in the cylinder 14 and includes a lower end communicated with the interior of the crankcase 12 and an upper outlet end 30 which opens into the interior of the cylinder 14 above the piston 18 when the latter uncovers the outlet end 30 of the passage 28 as it moves to its lowest point in the cylinder 14. Also, the portion of the cylinder 14 substantially diametrically opposite the outlet end of the by-pass passage 28 has an exhaust port 32 formed therein.

It is to be understood that the foregoing description of the model engine is of a substantially conventional model engine.

The exhaust port 32 has its outer end defined by an axially short neck 34 projecting outwardly of the corresponding side of the cylinder 14 and the exhaust silencer, which is generally referred to by the reference numeral 36, includes a tubular extension 38 having one end which is snugly telescoped over the neck 34. A U- shaped clamp 40 encircles the side of the cylinder 14 remote from the exhaust port 32 and is secured to the extension 38 by means of threaded fasteners 42 passed through apertured outturned cars 44 formed on the ends of the clamp 40 and threadedly engaged in threaded bores 46 formed in the extension 38. From FIGURES 2 and 3 of the drawings it may be seen that the extension 38 has a passage 48 formed therethrough which tapers toward the inlet end of the extension 38 and thereby allows partial expansion of the exhaust gases as they pass through the extension 38 from the inlet end thereof to the outlet end thereof.

The exhaust silencer 36 includes a first tubular airfoil-shaped member 50 which is open at its opposite ends and has a plurality of small diameter tubular outlet necks 52 spaced along and opening outwardly through the upper and lower camber areas 54 and 56- thereof. The ends of the airfoil-shaped member 50 are squared and the inlet end thereof abuts against a mounting flange portion 58 carried by and extending about the outlet end of the extension 38.

The exhaust silencer 36 also includes a second openended tubular member referred to in general by the reference numeral 60. The tubular member 60 includes upper and lower walls or sides 62 and 64 interconnected by means of an upstanding outer wall or side 66. The inner marginal edge portions of the top and bottom walls 62 and 64 terminate in vertical flange portions 68 and 70 which are recessed outwardly of the inner marginal edges of the top and bottom walls 62 and 64 and form partial inner wall sections. The opposing edge portions of the flange portions 68 and 70 are cut or relieved as at 72 so as to form an opening through the inner side wall of the tubular member 60 defined by the flanges 68 and 70 through which the tubular member 50 may be lengthwise inserted after the inner longitudinal edge portions of the top and bottom sides 62 and 64 have been spread slightly apart.

The spacing between the top and bottom walls 62 and 64 is somewhat greater than the spacing between the remote ends of the upper and lower necks 52 and the top and bottom walls 62 and 64 are longitudinally corrugated as at 74 and 76.

The outer side wall 66 of the tubular member 60 includes inwardly recessed portions 78 which are cen trally apertured as at 80 and headed and threaded fasteners 82 have their shank portions passed through the apertures 80 and threadedly engaged in the ends of the threaded bores 46 remote from the fasteners 42 with the heads of the fasteners 82 seated in the recessed portions 78. In addition, the flange portions 68 and 70 are apertured as at 84 and 86 and self-tapping screws 88 are secured through the apertures 84 and 86 and into the apertures 90 formed in the four corners of the mounting flange portion 58. In thi manner, the tubular member 50 is clamped between the outer side wall 66 of the tubular member 60 and the outer surface of the mounting flange portion 58.

The extension 38 is constructed of cast aluminum and may be finned if further heat dissipation is desired. Also, the tubular members 50 and 60 are constructed of sheet aluminum so as to also readily dissipate exhaust heat.

In operation, as the exhaust gases from the exhaust port 32 pass into the passage 48 extending through the extension 38, they are allowed to expand somewhat. As the exhaust gases continue through the passage 48 and open into the interior of the tubular member 50,

they are further expanded and then passed through the small diameter necks or apertures defined by the necks 52 and into the venturi areas 92 and 94 disposed above and below and extending along the camber areas 54 and 56. 7

From FIGURE 4 of the drawings it may be seen that rapid movement of the engine 10 in a direction toward the left as viewed in FIGURE 4 of the drawings will cause a rapid inflow of air into the forward or left-hand end of the tubular member 60. This air will be separated into the two flow paths indicated by arrows 96 and will be accelerated as it passes above and below the camber areas 54 and 56 and thus experience a reduction in pressure. Of course, a reduction of pressure at the outer ends of the necks 52 will tend to draw the exhaust gases through the necks 52 and thus appreciably reduce the back pressure of the exhaust gases within the tubular member 50.

If the model engine 10 is utilized in an airplane, the flow of air into the forward end of the tubular member 60 will be further increased by the propeller mounted on the forward end of the crankshaft 16 in the area designated by the reference numeral 98, see FIGURE 1. This of course will effect a still greater reduction of pressure above and below the camber areas 54 and 56 and thus further reduce the pressure of exhaust gases within the tubular member 50.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to.

What is claimed as new is as follows:

1. In combination with a combustion engine adapted to be rapidly advanced in a given direction and including an exhaust outlet, an exhaust extractor and silencer comprising a first tubular airfoil shaped member for said outlet extending in a second direction transverse to said given direction and having one end thereof communicated with said outlet, said tubular member having a plurality of outlet openings formed therein along the opposing camber areas thereof, a second open-ended tubular member, said first member having at least the other end thereof disposed in and extending transversely of said second member, said one end of said first member opening outwardly of one side wall of said second member, and said second member including second and third side walls spaced outwardly from and opposing said outlet openings and camber areas.

2. The combination of claim 1 wherein the crosssectional area of said first tubular member being appreciably greater than the cross-sectional area of said exhaust outlet.

3. The combination of claim 1 including a tubular extension defining a passage extending therethrough, said extension being supported from said engine with one end of said passage registered with said exhaust outlet, said first tubular member being supported stationarily relative to said extension with said one end thereof registered with the other end of said passage.

4. The combination of claim 3 wherein said passage increases in cross-sectional area from said one end thereof to said other end thereof.

5. The combination of claim 1 wherein said tubular members are constructed of heat resistant material having high heat transferring capacity.

6. The combination of claim 1 wherein said tubular members are constructed of sheet aluminum.

7. The combination of claim 1 including a tubular extension defining a passage extending therethrough, said extension being supported from said engine with one end of said passage registered with said exhaust outlet, said first tubular member being supported stationarily relative to said extension with said one end thereof registered with the other end of said passage, and a generally U- shaped clamp, said engine including a cylinder outwardly through one side of which said exhaust outlet opens, said U-shaped clamp being disposed about the side of said cylinder opposite said exhaust outlet and secured to said extension by threaded fasteners.

8. The combination of claim 7 wherein said silencer includes fasteners securing said second member to the end of said extension remote from said outlet with said first tubular member clamped between a side wall of said second tubular member remote from said one side wall thereof and the end of said extension remote from said exhaust outlet.

9. The combination of clam 1 wherein said second and third side walls of said second tubular member include corrugated portions extending longitudinally of said second tubular member, said corrugations defining inwardly opening channels in said second and third side walls References Cited UNITED STATES PATENTS 1,025,251 5/1912 Desmond 181-43 XR 3,318,412 5/1967 Bailey 181-40 XR FOREIGN PATENTS 332,109 7/1930 Great Britain.

ROBERT S. WARD, JR., Primary Examiner US. 01. X.R, 181-40, 63

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