Sept. 17, 1946. F. c. Ml-:LcHloR 2,407,719 CARBURETOR PRE~HEAT SYSTEM` Filed Feb. 1. 1944 3 Sheets-Smet 1 . .mw _ w _ _ _ _ _ _ _ _ v _ ku: INVEN TOR. Frederick Cßßlelcîez'or BY Sept. 17, `1946. 2,407,719' F.l c.fMELcHloR CARBURETOR PRE-HEAT SYSTEM 3 `Sheets-Sheet 2 Filed Feb. ' 1, 1944 III..l|,. .(Hf.1.4. ‘ f l ` ",________f’ BYv Sept. 17, 1946. F. c. MELcl-noR 2,407,719 CARBURETOR PRE-HEAT SYSTEM Filed Feb. 1, 1944 " „Qi/MW f H 3 Sheets-Sheet 3 BY` www-ww 2,407,719 Patented Sept. 17, 1946 UNITED ' STATES PATENT A"OFFICE CARBQRETOR _ „2,407,719 PREHEA’fr SYSTEM l ` ` I. \ ,. Fi‘ederickiflfMelchior, New York, N. Y.r Application-rennen 1, 1944, seriali-No. 520,629' :e claims. (cl. 12s-_171) > vide'means for proper 'cooling of the exhaustcol This invention relates `to improvements `>in air- » lector ring `and ventilation of the 'collector well, 'craft power plant 'installations and moreì particu whether or not ‘the carburetor 'heat is used, and to eliminate the `undesirablev effects Aci’ the cowl larly to the use and -disposal `’of engine exhaust -`heat and of 'the `air heated in the _process 'o'f cooling the engine and its cylinders. YMore `specifically myA ‘invention provides an flaps now in current use. ' The subject invention embodies -a vsliding Ven turi cowl to replace the conventional ‘cow'l‘flaps said Venturi cowl incorporating rigidlylatt'ached improved carburetor‘air prehheatsystem combin ing the coolingof thefexhaust collector-ring with thereto a shroud or muiî partly enclosing Vthe the ventilation of the engine -compartment and 10 exhaust collector ring in ‘the‘well and extending collectorl‘well. substantially along itheperiphe'ry. »As the :nuff In the 'conventional air-cooled engine instal moves With‘the sliding Venturi ‘_cowl `this lwhole lation `the `nose cowl‘is equipped with a series of unit forms with the rear ~cowl and’the diaphragm cowl naps attached to its trailing edge >and Aex a variable Venturi opening as ‘an `exit `aperture tending substantially A"along the periphery thereof except vfor the areas occupied by the air intake 15 'for the hot air-flowing through the exhaust col scoops for the carburetor and for >oi-l cooling. ~ lector well, such now being augmented by venturi When the cowl flaps are opened at an ‘angle the suction. the engine compartment thereby augmenting However, cowl 'flaps 'ventilation of the same. when `opened have the undesirable :effect of caus ing turbulence disturbing the air flow around‘the nacelle and part of the wing and -sometimes ad versely alîecting the control surfaces Vtol the ex tent that in some current'aircraft cowlf'flaps-can not be opened appreciably during night, To provide adequate pre-heating of’the 'car ` In the Aaccompanying drawings Figure 1 is a'vertical's'ectional view of'a nacelle embodying my invention; Fig. 2 is a horizontal sectional-view; 4deflection of the air flow 'cause's‘su‘cti'on out of Fig. 3 is a cross sectional view taken on Vthe line v3--3 of Figure’l. ' As'in the conventional installation the motor 25 |0=is mounted inthe nacelle fl I in the usuall man ner on-the `conventional mount ring ‘12. An air 'intake scoop I5 for the >oil cooler -maybe pro vided as is the -airin‘take or ram scoop T|16 'for buretor air as an anti-icing measure, the `con ventional installation Yalso embodies a Í‘shroud or the carburetor. These are usually mounted'with the scoop 'I5 at 'the ‘bottom and the >scoop f6 ‘at Vthe top ofthe `nose cowl l1. 'My invention con templates an engine'having »et-conventional ex haust collector ring 20 andan exhaust collector muff, comprising in effect a continuation ofït'he rear cowl, rigidly attached to the latter and"~ partially enclosing the collector well ìhou-sing the exhaust collector` ring or manifold. The shroud well 2| *formed by a diaphragm T22 and -a lmov or muiî is interrupted at the >top »and `bottom ofthe nacelle to accommodate air «scoops ‘to v‘the 35 able v'shroud member 23 attached to a sliding Venturi cowl `24. The -shroud 23 'is so shaped carburetor-and oil cooler. as to `form with the diaphragm «'2'2 `a vcollector It is usual to-locate over the collector well 1an well Asubstantially elliptical in cross section. A alternate air valve which may be adjusted at fixed-shield ¿451separates the upper part of the will to vadmit the l‘desired amount »of hot vair'fro'm the collector well where it has been heated 40 collector well l'from'the -engine‘- compartment, said through Acontact with the lexhaust fcollector iin'g.~- » This arrangement provides adequate carburetor shield extending over a sector 'sufñ'cientl‘y large to compel the cooling Uair 'to ii'ow ' substantially along the Iexhaust Acollector well before entering the carburetor, when heated air is used inthe same. stallations lacking Vsuch arrangement. However, 45 The Venturi `cowl member '24 >and vthe/shroud 23 are preferably made in one piece vextending it does not render optimum ventilationfo'f‘the> yfrom the edge’25 of‘the'shie‘ld 145 around tothe engine compartment under all conditions, `nor lopposite fedge 21. However, if desired, ‘themov does it `provide `for the proper cooling of thejex able cowl Vmember "24 may extend `Vfrom theedge haust collector ring and ventilation of 'the 'col lector well, especially when lcin'bur'etor heat is 50 "2110i the- plate 445 lto theedge ‘28 of the oil cooling "scoop t5 and a ‘similar -cowlV member "35iïhaving not used, thus causing heat to `be trapped »which l Va shroud m29 maybe‘fmounted on `Vthe other `side in turn results ïin undue 'heating o‘f the acces air heat to cope with normal iicing conditions, which has `been found not tobe the caseiinän sories compartment as ‘well `as thermal punish- ~ ment of various pertinent-parts. An object-of the present invention fis fto pro ofthel nacelle, it'being understood that thellength of the movable cowl '24 and'its `shroud. 23 ‘need 55 not be limited in area. The movement of fthe 2,407,719 3 4 cowl 24 and the shroud 23 may be controlled effect of cowl flaps when opened disturbance oi'. manually or thermostatically by any suitable the air ñow causes a drag which represents a means such as the thread bar 30 engaging the definite loss in terms of horse power. In the sub bracket 3| so that as the bar 30 is turned theV ject invention the method of disposing of heat cowl will move accordingly. 5 through Venturi action causes no such disturb Mounted under the ram scoop I6 adjacent to ance with consequent losses. Not only will my where it enters the engine 33 is an alternate air construction further control the heat to the car Valve 34 separating the collector well 2l from .the buretor by virtue of increased heat transfer ef ram scoop I5.' The -valve 34 -'may be operated in ficiency due to improved air flow through the any suitable manner and it may .or vmay not be 10 collector well and around the exhaust collector coordinated with the movement of the Venturi Y _ring but as a direct consequence is obtained cowl 24 or, where two cowls are used, 24 and 35. *» greatly improved cooling of the exhaust collector In full cold operation air will fbe" directed Y ring and ventilation of the collector well together with improved ventilation of the engine compart through the ram scoop I6 into the ,carburetor'at ment and cooling of the engine under all condi 3-3 as in the conventional installation.- Additional air will pass through the nose cowl H absorbingy tions of iiight. . , . . ' heat from the motor l0 and cooling Ithe motor I claim vand will then pass into the collector well through 1. In combination with an engine installation the opening 38 and 39 formed between the mount including a nacelle having a nose cowl and an ring and the movable shroud 33 thus absorbing 20 air. intake scoop leading to the carburetor of said heat from and cooling the exhaust collector ring. engine and an exhaust collector ring, of a car In operation .the action of the air past the buretor pre-heat system includinga slidable cowl nacelle will create `a Venturifsuction in the Ven turi slot between the slidingv cowl 24 -and the , rear cowl 40 to suck the air over the motor and member extending from either side of said air through the collector well around the exhaust collector ring. With the valve 34 closed the air going to the carburetor will be direct from the shroud on said slidable cowl forming with said diaphragm a collector well around said exhaust collector ring, a valve leading from said collector well to said air intake scoop, means for selec tively operating said valve and said slidable‘cowl scoop, a diaphragm extending from said engine mounting to the outer edge of said nacelle, a outside. The valve may be operated either man- . ually or thermostatically so as to allow a, required 30 portion of the heated air from- the collector well to determine the amount of air` passing through -to mix with- the air coming through the scoop I6. YNaturally the -greater the opening of the `valve34v the moreheated air carburetor. ,- I I ' will pass to the , said collector well and the amount of air passing from said collector well into said air scoop. 2. In combination with an engine'installation including a nacelle having a nose cowl and an air - By operation of the Venturi cowl 24 the mass flow of air over the cylinders-can be effectively controlled. This mass flow being constant for a given set of conditions it is‘fevident that the. amount of heated air transmitted to the carbu 40 intake scoop leading to the carburetor of said engi-ne, said installation including aconventional mount ring and an exhaust collector ring, adja cent thereto, of a Ventilating and carburetor pre heating system including a diaphragm extending from said mount ring to the outer edge of said retor will depend upon the ratio of the opening of the Venturi cowl 24 to that of the ,alternatev nacelle, a slidable cowl member extending from air valve 34 as heated air can only ñow tothe either side of said air scoop, a shroud on said carburetor by way of the collector well. It is also slidable cowl forming with said diaphragm a col evident that the carburetorîmust ñrst obtain its 45 lector well about said exhaust collectory ring, share of the mass ilow of cooling air passing means for moving said slidable cowl and shroud through the engine compartment, the sliding within said nacelle to vary the opening from the Venturi cowl 24 being open just enough'to-»drain - interior of said nacelle to the outer air, a valve out the remainder, said opening to ‘be-governed? leading from said collector well to said air intake primarily by >desired cylinder head temperatures. 50 scoop, and means for operating said valve to con trolthe amount of air passing from said collector It follows that when no hot air is admitted to the carburetor the opening of cowl 24 must-~ be cor respondingly greater' and, likewise when maxi mum carburetor heat is needed, the opening of,` cowl 24 should be barely large enough to main tain cylinder temperatures within permissible limits. By thus properly manipulating the Valve wellinto said air scoop. ' 3. In combination with an engine installation including a nacelle having a nose cowl and an air intake scoop leading to the carburetor of said en ‘ gine, said engine installation including» a conven tional mount ring and an-exhaust collector ring, adjacent thereto, of a Ventilating and carburetor Vpre-heating system including a diaphragm ex 60 tending from said mount ring to the outer edge 'To further improve the cooling of the -exhaust of saidnacelle, a slidable cowl member extending collector the inner edge ofthe mufr- or-shroud from either side of said air scoop, a shroud` on is rounded or shapedin a manner sc_as to form said-slidable cowl forming with said diaphragm with the mounting ring andthe diaphragm ang~ a collector well around said exhaust collector ring, entrance aperture for the cooling 'airinto the means for moving said Vslidable cowl and shroud collector well', saidV aperture beingalso in the within said nacelle to vary the opening from the nature of a Venturi slot or opening for the pur interior of> said nacelle -to the outer air, a valve pose of providing a more uniform and effective leading from said collector well to said air intake air flow about the exhaust collector ring which„~-~ scoop,y and vmeans for operating said valve to con it will be noted, is elliptical in cross section Vfor 70 trol-the amount jof `air passing from saidcollector still further’improvement or flow around it. Such well-into said air- scoop, said'means being op improved ñowirenders better heat transfer-'and erated to prevent any- air- from said collector well consequently _a greater degree »of pre-heat avail from passing into'said air scoop or to mix the 34 and cowl 24”-the air. going into the carburetor as well as~the cylinder VAtemperatures can beef-f fectively controlled-l vable.> », n - - - _ » ,mi In addition to the aforementioned undesirable heated air with air from said air scoop. ¿ v .v FREDERICK C. MELCHIOR.