US1638780A - Exhaust silencer for internal-combustion engines - Google Patents

Description

EXHAUST SILBNCER FOR INTERNAL COMBUSTION ENGINES J. NEIL Filed Anril 1924 nected by means of any suitab Patented Aug. 9, 1927.

, UNITED STATES PATENT OFFICE.

JAMES NEIL, OF ANNIESLAND, GLASGOW, SCOTLAND.

EXHAUST SILENGER FOR INTERNAL-COMBUSTION ENGINES.

Application filed April 24, 1924, Serial No. 708,771, and in Great Britain October 12, 1923..

My invention has reference to improvements in and relating to exhaust silencers for internal combustion engines, and has for its object the provision of an improved device, wherein the exhaust from an internal combustion engine is passed into a chamber gradually so that it may expand and be discharged from said chamber into the atmosphere easily and freely, in order that the noise attendant upon the shock of a body or volume of gases meeting the atmosphere by sudden or violent expulsion through the engine exhaust pipe may be eliminated or greatly reduced while the back pressure upon the gases due to the inertia of the atmosphere may also be reduced, thereby effecting an economy in the fuel used in said engine.

This invention consists of an exhaust silencer comprising an inner pipe having its one end in open communication with the engine exhaust and its other end in open communication with the atmosphere and a spirally corrugated outer casing forming a spiral chamber around said inner pipe, said chamber being bounded by said pipe and by the spiral corrugation of said outer casing. The inner pipe, which extends through the outer casing and projects from both ends of same, is formed with perforations arranged spirally round the same. The corrugated outer casing may be of conical formation and the spiral corrugation may be of increasing pitch so that the chamber around said inner pipe may have a cross-sectional area which increases from the inlet to the discharge. At a point near the discharge end the inner pipe is plugged. Between said plug and the end of the outer casing adjacent to same the inner pipe is formed with openings so as to pass the gases from the end of the spiral chamber .into the end of the inner pipe and out to the atmosphere through the end of the inner pipe. The said plug may be of conical formation.

In order that my said invention and the manner of carrying the same into effect or practice may be'properly understood, I have hereunto appended an explanatory drawing which is an elevation, partly in section, of an exhaust silencer as constructed according to this invention.

Referring to said drawing In carrying this invention into effect or practice, the one end 6 of a pipe a is cony constructed coupling to the engine exhaust pipe. The,

other end 5 of the pipe at is open to the atmosphere. The pipe a is provided with a plurality of perforations 0 arranged in the form of a spiral as shown.

Surrounding the pipe (1 is an outer casexternal surface of the casing is increased which provides for increased cooling surface.

The corrugated casing cl may be, as shown,

of conical formation, that is, the diameter of the casing d at the end eof the pipe (1 may be smaller than the diameter at the other end. Preferably, the corrugations of the outer casing are formed as illustrated. Longitudinal sectlons of the corrugations are of similar configuration. The distance of each corrugation from the pipe a and the pitch of the spiral increases as the spiral corrugation is developed around the said pipe so that a chamber of increasing area is provided around the pipe a.

At or about the point 9 in the pipe a a division wall or plug 0 is arranged or fitted.

This plug may be of conical formation as shown so as to diffuse the gases. Between theplug and the adjacent end of the outer casing, openings a are formed in the inner pipe a.

The exhaust gases pass into the pipe a through the end 6 from the engine, then through the perforations 0 into the chamber f, back into the pipe or through the openings n and out to the atmosphere through the end I).

i I claim:

1. An exhaust silencer for internal combustion engines formed of a perforated inner pipe and an outer casing having a helical corrugation defining a helical chamber around said pipe; one end of said pipe being open to the engine exhaust and the other end of said pipe being open to the atmosphere with a division between said ends substantially as herein set forth.

2. Apparatus comprising a perforated inner pipe; means disposed in said pipe for obstructing the passage of gases therethrou h; and a casing surrounding said pipe ormed with a helical corrugation so as to form a chamber with increasing cross-sectional area.

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3. Apparatus comprising a perforflied inner pipe and having a cone disposed within said pipe adjacent to one end thereof; and a helically corrugated outer casing forming a helical chamber around said pipe.

4. An exhaust silencer com-prising a pipe having a series of perforations; and a helically corrugated" casing surrounding said pipe, said corrugations having an increasing pitch.

5. In combination, an exhaust pipe having a series of perforations; and a helically corrugated casing enclosing said pipe, the radius of said helix corrugation increasing with the length thereof.

6. An exhaust apparatus comprising a perforated pipe; and a helically corrugated casing enclosing said pipe, the pitch and radius of said helix increasing with the length thereof.

' 7 An exhaust silencer comprising a perforated pipe, having an end obstruction adjacent to one end thereof in the form of a cone with the apex thereof extending toward the inlet end of said pipe; and a helically corrugated casing enveloping said pipe so as to form a helical chamber for the gases passing through said perforations.

8. An exhaust silencer comprising a perforated pipe having an end obstruction adjacent to one end thereof in the form of a cone with the apex thereof extending toward the inlet end of said pipe; and a helically corrugated casing enveloping said pipe so as to form a helical chamber for the gases pass-' ing through said perforations, said pipe having an opening intermediate the end of said casing and said obstruction adapted to receive'the gases, whereby gases may be dis charged from said casing.

JAMES NEIL.

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