US2984967A - Exhaust temperature air-cooling system - Google Patents

Description

l hl 6 A. M. CADDELL Filed Jan. 27, 1959 Hill il HU Il E lll lll EXHAUST TEMPERATURE AIR-COOLING SYSTEM May 23, 1961 moN vor

United States Patent EXHAUST TEMPERATURE AIR-COOLING SYSTEM Alfred M. Caddell, 1318 W. Hunting Park Ave., Philadelphia 40, Pa.

Filed Jan. 27, 1959, Ser. No. 789,379

4 Claims. (Cl. S0-'30) The present application is in part a continuation of pending application entitled Internal-External Air Cooled Manifold, filed Dec. 30, 1954, Serial No. 478,793, now abandoned.

'I'his invention concerns a new type of exhaust system which may include a collector ring as used in radial internal combustion engines or utilize a straight-through form of manifold for employment with either a stationary engine or an engine that powers an automobile or other vehicle, including marine craft.

The object of this invention is to reduce as simply and as fast as possible the temperature of the exhaust gas before it reaches the atmosphere, thus making possible an increase in the power output potential that is now choked by mufing and other conflicting phenomena herein described. In addition to such power increase, silencing of the exhaust automatically is achieved.

With the exception of those exhausting directly to atmosphere, every engine known to this applicant is equipped with a muffler which stifles noise but, while doing so, stitles the engine as well. When a muiiier is employed, the very force that drives a piston virtually remains pent up while it is being discharged. Back pressure results, putting a brake on piston movement and, therefore, power output. Moreover, the resulting sacrifice in power involves a serious waste of fuel that was initially required to generate the energy. Compared to what it could be, even with the best of engines equipped with a muier, the performance is sluggish.

Due to such incomplete exhausting, a considerable percentage of the tired gas remains in the cylinder to vitiate the incoming charge of fresh fuel-air mixture. At present, the charge that does enter becomes relatively impotent compared to the quantity and quality of the mixture that otherwise could ll the cylinder. Therefore, by assisting in the removal of dead gas, an increase in net power output automatically results.

Further, by promoting more through combustion of the unburned gas discharged with the exhaust, troublesome smog that covers city streets like a blanket is prevented.

This irritating smog is caused by a part of the gas that is not burned as it passes through an engine. As one example, cars idling in traffic do not utilize all the gas delivered to the cylinders by the carburetor. Considerable of it emerges from the tail pipe as vapor or as partly burned derivatives known as alhehydes which react with components of the atmosphere to produce new chemical compounds that weigh heavily and contribute to the acrid quality of smog.

Creation of vacua When discharging openly to atmosphere without any attempt at cooling and having high velocity, the exhaust slugs over-extend themselves, causing equally as high vacuums to form in their wake. Just as instantly, these vacuums pull back some of the gas into the pipe whence it came. This pull-back can be seen when exhaust gas is directed through a Pyrex tube in the presence of titanium tetrachloride smoke. After every discharge smoke flashes back in the tube to ll the created vacua, only to be met with the discharge of the next slug of gas. This collision of forces translates into an obstacle that detracts greatly from power output.

Exhaust silencing Still another phase of exhausting-that of silencinghas interrelated power-consuming and audible discomfort effects. When discharging through open stacks, the exhaust slugs violently displace air, causing vacuum pockets to form just outside the stacks. Action and reaction being equal and opposite, the instantaneous closing of these pockets by air, which itself is under heavy static pressure, causes the well-known thunderclap noises, the molecules of the air colliding with each other at great speed. Aside from the wracking of nerves, the resulting vibration caused by such air collisions sets up standing waves in the exhaust pipe lwhich reflect all the way back into the engines cylinders, there to be met by concussion waves generated by the next-following explosion. This powerconsuming and noise-recurring cycle continues throughout the run of the engine.

The exhaust system described herein is designed to supplant a mutlier and thus avoid the drawbacks imposed by such a device upon the engine.

The system is comprised of an inner and an outer wall and a duct continuing as an extension of said outer Wall. Also, an entrance duct for conveying air to the air-cooling part of the system. Each of said manifold walls and duct may be of round, square or other appropriate construction. They are separated from each other by spider means for permitting the flow of air therebetween. A plurality of pipes, each connected to an exhaust port of an engine, convey exhaust gas to the inner gas-dow area of the system, which area is defined by the diameter of the inner wall. Part of the cooling air that enters the space between the walls is intercepted by protruding portions of conduits mounted in inserts secured in the inner wall. Whereupon the air is conveyed toward the center of the gas-iiow area by another portion of the conduits, which portions are designed to cause deflection of the gas therearound and thus, through suction, superimpose the speed of the exhaust gas upon the air. The result is a precipitous lowering of the temperature of the gas due to the admixture of cooling air therewith inside the inner wall.

In addition to the foregoing suction of air into the gas-ow area, means are also provided to insure maximum suction of air through the space between the inner and the outer walls.

Absorption of heat by convection, which provides for the rapid passage of air over a hot surface, is the best known means of extracting heat from an object, be it a stove or an exhaust manifold. Toward that end, a duct is provided as a continuation of the shroud wall and a rain-drop form of cone is interiorly supported by said duct. This cone is positioned across the discharge end of the inner wall, so that the gas on being deected across the air-ilow space by the cone will likewise er1- train air at its speed and thereby cause greater lio-w thereof through said space.

Still further entrainment of air is achieved by providing for its deliection in the continuation space between the duct and the cone. By means of inwardly projecting protuberances that extend into said space from said duct wall the air traveling through the passageway strikes these protuberances and in doing so is deflected into the gas stream exhausting from the inner gas-flow area, the gas stream in turn, increasing the velocity and volume of air being drawn through said passageway. Also, by means of co-functioning indentations in the sides of the cone, extreme turbulence is set up in the gas-air mixture. The lowered temperature of the mixed gas and air presents a lower pressure area for the on-coming gas and Yair to rush into. This, in turn, invitesthe removal of more heat internally and externally from the inner manifold wall and thus promotes superior exhausting.

This duct and cone may be comprised of a heat-resisting, non-metallic substance having sound-deadening properties superior to that of metal. v

Also, to increase the supply of cooling air to the system, pressurized ambient temperature air may be supplied thereto by means of a fan'or propeller, or by heading the air entrance duct into the wind created by the passage of a vehicle therethrough. Y Y

A further advantage of lowering the temperature of the gas as speedily as possible lies in the permanency of the inner manifold wall itself. By maintaining consistently lower temperatures in the exhaust system, the metal comprising the walls thereof would be subjected to less stress and possible rupture. Under present operating conditions, manifolds get red hot, especially radial engine collector rings, and expand and contract to an alarming degree with alternate changes in temperatures. Sometimes as much as an inch occurs in the dimensions of a manifold, both circumferentially and longitudinally. Studs snap and clamps that join sections together often burst. Safeguarding the manifold system from such po tential danger is, therefore, an important object of this invention.

Other advantages offered by this internal-external cooling means will become apparent as the herein description proceeds.

Inthe drawings:

Fig. 1 is a side view of a radial engine, showing a tractorpropeller that provides motion for air entering the duct that communicates with the shroud wall and the space between the shroud and the inner open-end wall; also, the several individual pipes leading from the engines exhaust ports and the conduit entrance portions which extend into the space wherein cooling air is ilowing.

Fig. 2 shows, for ptuposes of clarity, an exaggerated viewof an exhaust manifold system adapted to an inline automotive engine, individual pipes being shown in dotted outline for conveying the gas from the engines cylinders to the manifolds inner wall; also, entrance ends of the conduits for conveying air directly into the gas-How area. The shroud wall is shown in cross section.

Fig. 3 is a cross sectional view of the manifold system showing the outer shroud wall and, separated therefrom by spiders, the inner gas-conveying wall. The wall-like inserts in which the converging-diverging conduits are mounted are shown welded in position. Also shown is the cone element for deecting the gas from the gas-flow area across the discharge end of the air space between the shroud and the inner wall for suction of air through said space.

Fig. 4 shows a square form'of open-end wall with a plurality of apertures in each of its sides for the reception therein of inserts carrying the converging-diverging conduits. A round open-end wall would have appropriately contoured apertures for the same purpose.

Fig. 5 is a frontal view of an insert showing the dividedhalf construction with semi-apertures formed in each half for encompassing the converging-diverging conduit which is, on assembly, welded in the inner wall. Upon assembly, too, the divided constructions are welded to each other and the completed inserts secured in the apertures provided in the walls.

Fig. 6 is a top view of a square form of manifold system, showing the outer shroud wall, the inner open-end wall carrying inserts which, in turn, carry converging-diverging conduits for permitting the exhaust gas to entrain air most eciently into the gas-ow area. Spider means for spacing the inner open-end wall'from the shroud wall are also shown.

Fig. 7 is an end View of an individual insert having a converging-diverging conduit mounted therein.

Fig. 8 is a view similar to that shown in Fig. 3, depicting the air-conveying ducts, the outwardly ared rim at the discharge end of the conduits for deflecting the exhaust gas therearound to promote entrainment of cooling air. Serpentine arrows 13 indicate the -tortuous travel of the gas to promote turbulence thereof due to its deflection around the diverging ends of the conduits, which deflection creates a negative pressure area across said diverging ends and promotes the ow of cooling air into the gas-how area.

Fig. 9 is a view looking downward, taken on the line 9-9, Fig. 8, showing the inwardly extending rim of the diverging conduit ends and spider means separating the inner from the shroud wall.

Exhaust gas is conveyed from engine 1 through individual pipes 2 into gas-ow area 3 defined by open-end wall 4, Figs. l and 2. As shown clearly in Figs. 1, 2, 3 and 8, this open-end wall is spaced from outer shroud wall 5 by means of spiders 6, which permit the ow of atmospheric air through space S. Shroud wall S may be connected to air intake duct 7, illustrated in Fig. l, said duct being iitted with a bell mouth 7A which faces into the wash of propeller 8 and which is attached to shroud wall 5 by means of flange 15. As an alternative, shroud wall 5 may have an entrance end such as is shown at 5A, Fig.V 2, and have associated therewith a number of individual shroud walls 5B, Fig. 2; which AWalls spatially encompass exhaust pipes 2 that convey the gas from each cylinder of the engine through wall 4. As another alternative, instead of fan or propeller means being employed to ram air into space S, the manifold system may be mounted on a vehicle to head into the wind for increasing the dlow of air through said space.

The inner and its accompanying shroud wall may have a round, square or oblong construction. For Yan equivalent area occupied by a round construction, a square construction would offer more internal and external surface. A square construction is shown in Figs. 4 and 6, whereas a round construction is illustrated in Figs. 3, 8 and 9.

As shown in Fig. 4, a plurality of shouldered edges in wall 4 form apertures 9 in the inner wall. A similar type of appropriately contured apertures may be formed in a round wall. Irrespective of the type of construction employed a like number of matching shouldered inserts 10 are formed to occupy said apertures.

These inserts initially are of divided construction, as shown in Fig. 5, and have openings 10A formed in each of the halves. These half-openings encompass conduit 11 at the throat portion thereof and `are welded thereto, as at 12, Figs. 3, 6 and 8; after which the insert lhalves would be welded together to comprise a complete insert which may, in turn, be welded to the shouldered edges forming apertures 9.

Conduits 11 are of converging-diverging construction, the portion 11A that protrudes outwardly from its respectlve insert Abeing shaped to intercept air owing through space S, while portions 11B Vextend inwardly and diverge to promote suction of air across openings 11D by the gas owing at high velocity therearound. As shown in Figs. 3, 8 and 9, right angular flanges 11C are formed at the discharge ends of diverging portions 11B to promote this maximum suction of air. Fig. 8 shows serpentine arrows 13, which carry small circles that indicate suction of cooling air, whereas'the ow of gas around anged conduit ends 11C is illustrated by the small arrows 13A in Fig. 9.

In addition to the exhaust gas surrendering heat to co'oling air entrained inwardly as above described, means are also provided -whereby the gas also entrains air directly between the inner and the shroud walls fo'r cooling the inner wall by convection. Duct 16, Figs. 1, 2 and 3,

is formed to be secured to shroud wall 5 at flange 17, being secured thereto by a plurality of bolts 18. Cone 14 is secured to duct wall 16 by means of spiders 19, which permit the passage of exhaust gas and air therethrough and which provide space -S between the cone and duct. This cone may have any desired shape for deecting the exhaust gas across the discharge end of space S, thus imparting to the air the velocity of the gas-air mixture issuing from the gas-ow area defined by wall 4. The purpose of the cone being to deflect the gas whereby maximum suction of air through space S may be achieved, it may be mounted at any desired position beyond the terminus of wall 4. Arrows 33 show the flow of the gas at this point, indicating the pickup of air from space S as per arrows 34, Figs. l, 2 and 3.

As illustrated in Fig. l, this cone may have a shape that terminates at a right angle to the entering end thereof to correspond with the contour of the duct wall. This duct, in turn, may terminate in a ange, as at 20, Fig. 3, whereby it may be coupled to' a device entitled Rotary Temperature-Reducing Exhaust Silencer, described in pending application, Serial No. 675,107, tiled July 30, 1957, for further processing before the gas is lfinally discharged to atmosphere.

To assist further in the flow of cooling air from atmosphere and the consequent reduction of exhaust gas temperature, protuberances 21 are secured to the inner surfaces o'f duct 16 to further deflect the mixture of gas and air flowing through space S; also, indentations 22 are provided in the sides of cone 14 to cause further turbulence of the gas-air mixture and promote through said turbulence still lowered temperature of the discharging gas. If this system is mounted in an aircraft, flared end 16A of the duct would enhance still further the discharge of said gas-air mixture to atmosphere.

Both duct 16 and cone 14 and protuberances 21 may be constructed of a substance capable of withstanding the temperatures of the gas-air mixture without surrendering their shapes.

Fig. 2 indicates an exaggerated mounting of the manifold system of this invention on a -cylinder in-line engine 23, the gas leaving exhaust ports 24 and being conveyed by pipes 2 into the gas-flow area deiined by inner wall 4. Individual shroud assemblies B are provided for a purpose similar to that described hereinabove.

Fan assembly 25 may be employed in association with this engine in a frame construction 26, which carries ball bearings 27 to support shaft 28. This fan may be driven by gearing or V-belt means, pulley 29 mounted on said shaft being connected by V-belt 30 to V-pulley 31 mounted on crankshaft 32 of the engine.

Having described my invention, I claim:

1. An exhaust cooling and silencing means fo'r an internal combustion engine having a plurality of exhaust ports and driving an air propeller, said means comprising an internal-external air-cooled manifold formed by an inner open-end wall dening a gas-tiow area and a wall spaced from said inner wall to comprise an open-end shroud to establish a passageway for the travel of ambient temperature air therethrough, a duct communicating with atmosphere for delivering air to the space between said inner wall and said shroud, a pipe connected to each exhaust port and extending through said shroud and through said inner wall for delivering exhaust gas under engine discharge temperature and pressure into said gas-flow area, a plurality of apertures provided at spaced intervals in said inner -wall and a like number of wall-like inserts fo'rmed to t said apertures and be made secure to said wall, an open-end tubular conduit mounted in each of said inserts, each of said conduits having a portion that extends outwardly from said inserts into said passageway for intercepting said ambient temperature air, said portion converging to form a throat for passage through said inserts, said throat having a cross-sectional area less than that of said converging portion for permitting increased travel speed of said air through said conduits, said conduits having a diverging portion extending inwardly from said inserts for delivering said air to the center of said gas-flow area.

2. The exhaust cooling and silencing means ydescribed in claim 1 wherein said inserts have a twin-half construction and o'penings in the halves thereof that face each other for encompassing said conduits, said conduits being made secure to said halves and said halves being made secure to each other `for mounting in said apertures.

3. The exhaust cooling and silencing means described in claim 1 wherein each of said tubular conduits has a diverging end that extends into said gas-dow area and defines an opening that faces in the direction of travel O'f said exhaust gas, said end terminating in a right-angular flange extending toward the center of said gas-flow area for inducing suction of air from said passageway into said area by the iiow of said exhaust gas therearound.

4. An exhaust cooling and silencing means for an internal combustion engine having a plurality of exhaust ports and driving an air propulsion means, comprising an internal-external air-cooled manifold formed by an inner open-end wall dening a gas-dow area and an outer wall comprising an openend shroud, each of said walls having an intake and a discharge end, a space provided between said shroud and said inner -wall to establish an airiow passageway, a duct for conveying air pressurized by said propulsion means into said passageway, a pipe connected to each exhaust port and extending through said shroud and through said inner wall for delivering exhaust gas under engine discharge temperature and pressure into said gas-how area, a duct comprised of an openend Wall removably secured to the discharge end of said shroud wall, a plurality of protuberances extending inwardly from said duct wall into said passageway for deecting air into the gas stream discharging from said gasiiow area, a co'ne having a number of indentations fOrmed in its surface and a tapered entering and a tapered trailing end spatially supported by said duct, the entering end of said cone extending partially into the area dened by the discharge end of said inner wall and said indentations being positioned in said cone surface to coact with said protuberances for increasing turbulence in the air owing through said passageway.

References Cited in the file of this patent UNITED STATES PATENTS 1,027,469 Forney May 28, 1912 1,370,197 De Bolotoi Mar. 1, 1921 2,396,208 Serre et al. Mar. 5, 1946 FOREIGN PATENTS 354,815 Italy Dec. 9, 1937

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