US2004869A - Charge forming device - Google Patents

Description

June '11, 1935.

J. W. HOGG CHARGE FORMING DEVICE Filed March 26', 1934 ing to an internal combustion ;engine,=- tuel"and Patented Junell, I

I CHARGE rosmqisevmy I dohnwebb flogzrPlaner-china. '1934', Serial- No. #17 ,476]

Y ,1 ihprnc 'tin ai-6H 26, .3 c lil l-f This invention relates to, charge formi ngg de: s; an i c mprises, p a o supplying,

and mixing two fluids in fixed relative proportion; and more particularly. to apparatusfon'supplyair in predetermined relative proportionand in variable total volume, said apparatus comprisinga.

variable opening, valve adapted to; control a -flow of fuel and a variable opening valve adapted tocontrol a flowof air the two valves being operaatively interconnected means ior establishinga differential pressure; and means. adapted to re-H for establishing a differential pressure in .the air flow, means adapted to respond to said fuel flow;v differential pressureand means adapted to..re,-,

spond to said air fiow ldifierential pressure, each of said pressure responsive means being adapted to p a th valves. means for ,combining .the two flows, and throttling means for varying the total amount of combined flow; all as more fully,

hereinafter set forth andas claimed.-;

In many chemical processes and operations necessary to mix two different fluid flows,such as gases orliquids, in ilxed relative proportion, under varying rates of combined now. In many cases} the pressure on the twocomponent fluids fluctuates, as by variations injhydrostatichead, in pump pressure,.etc.. It'has 'been a desideratum to proa vide a simple means for automatically proportion- :ing and mingling two component'fiuids in constant relative proportion,independently:of flue-1;

tuationsinpressure in either component fluid or of fluctuations fiow'.'

The present invention provides simple means adapted to automatically mixtwo fluids in constant proportion. Whileit is of general application, it will be described in a particular applica- 1 tion: embodied in a bustion engines.

carburetor for internal com- In the internal-" combustion engine. art 7 it is; customary to supplyto the cylinders air and a flow of fuel, 'whicl'irnay be gas, gasoline or oil.,;,

When liquid, fuelsa're used, it is usual to provide 7 for spraying or vaporizing the fuel. before it reaches the cylinders. .Various types 01 carburetors and mixing valves. have found usefor performing these, functions. In generalthey comprise, in the case ofgasoline motors, an airconduit leading to the intake of the cylinders, and means for introducingliquid gasoline into, air flowing through the conduit. The conduit is usually provided at some point-with, a yenturi or other means for, producing anarea of reduced pressure, that is .high "suction; f'and the gasoline "inthe 'total amount of combined a'butterfly valve or the like. i

In many cases it is desirable to provide a s'ub=' stantially constantproportionof gasoline and 'a'ir at different throttle openings and at different is introduced at:this"point,: as byabiett'ori Jets; In the usual-carburetor some sortb! throttle? device for. the air-gasoline mixture isproVided:

rates of air fiow; ,thatis at different engine speeds prising merely a- -gasoline. jet-opening into the air intakeconduit; while it may be designed soas to' deliver the, correct mixture *for. one given engine and loads. The simplest form of carburetor, com

speed, does not then provide uniform proportion ing, at different loads. and speeds; Atincreased en ine speeds, the flow of air. into" .the..engine increases, but the proportional amount of i gasoline taken up by the air increases faster than therate:

the simple type-cicarburetor. described; .1 I

constanttmixture at all speeds.;;.-In some 'typesl of airflow. Hence,=with:this sort of elementary:

carburetonif it is adjusted correctlyior medium: speeds then at high speeds itwill'deliverani ixture 1 too-richingasoline. This defect is inherentlin.

Most modern: carburetors-for. variablenspeed' engines represent additions to, or modifications of, thiselementary form of carburetor,- withrthe objectof. adaptingit to deliverra more or less an auxiliary ,air valve is: provided, adapted to open to a greater or less=degree at highe'r'engine by the jet...

speeds todilutethe over-rich mixture-furnished Some types make use. of met'eringsoix Q pins, valves in the fuel linellinkedto-thethrottle or multiplegasolinejet; devices in which dil er'erit i um r of ets arethrown mm 'action at 'dif ferent enginespeedsjall with theiidea. of 8801112 ing correct proportioningunder different speeds 1 and loads.

None of these in operation. In earburetors'ofthe valve. type, for example, having a devices is entirely satisfactory-{ simple air=- V v spring-re? strained flapper-valve adapted to be opened un--'-i der intake suction, the mixture is. byno means-i V constantat different speeds. 'Iheretis apt to" be an abrupt change in proportioningwhen the spring comes into action; and'moreove r the natureof the restraining forceexerted. on theair valve by acylindrical coil spring is such thatthe 7 air valve opening is not strictly correct except at" v one given speed. Attempts have beenmade to control the air valve by means of double-springs,"

tapered springs, etc. but these are "still not satis factory in insuring-correct proportioning andmoreover are likelyto get out ot adjustment."

,According to the present invention Iprovide' 5 I a carbureting device adapted in its basic formto automatically supply to an engine a constant ratio of air to gasoline under different loads, different speeds; and different pressures in'the fuel line and air intake. 1 do this by providing linked valves in the fuel. inlet lineand in the airintake fcon'duit, pressure responsive means in the fuel line. and the intake conduit, and means whereby the pressure responsive means control the valves according topressures in the fuel line and the intake conduit. While, ,as stated. my devicein its basic f for'rn is aQP-Dted to deliver ,a constant speeds and'thussecureeconomy. -The. new derestricted oriiiceproducesia differential pressure a .Fig. 2 is aview in vertical 'In' the drawingyinwhich like acters indicate like parts throughout, Fig...-l'- showsv a 3 carburetor device comprising a mixing, chamber ill/adapted to'be attached by means ofa flange II to the intake manifold (not shown) of intemal combustion engine. throttle valve-i2 of the ordinary butterfly type is mounted in the chamber a.sv shown. Other formsof throttling devicesmaybeemploye'd. The flow proportioning means comprises a valve' ll for fuel and .a .valve. for air. two valves are mounted onca-singleshafti5 as shown and-co-f operate with-conical seat members-'li andilfi' Thejmixing. chamber ismerged, as shown, I with a cylinder l8 communicating with an intakecon diiitrlO-for air. SeatJIis-mounted in the cylinder by-meansof a partition 20 as shown. one; end-of. shaft Ii is attached as atil toa'. piston ii-inflamed to slide freely-incylinder l8;while'=l vice is simplebut'presents several "advantages over ordinary carburetors. The device employs no float bowl and is able to function properly in anyposition. Moreover it is well adapted for' use incorijunction with .a supercharger.;. Hence: it is well suited for aircraft engine carburetion. In.- the,. accompanying drawing: I have bshown several forms of a specific embodiment of myiri- 1 Fig. 1 is aiview in vertical. section of a "carbu retor .for' liquid fuels; iv

form of carburetor; i

Fig.4 is a view in: vertical section of a modified form; ofcarburetor employingsliding seats: V '.Fig.=4 isa view in vertical section 01'. a modified:

form of mixing device. I reference charmaintaininga'relatively leak-proof seal; A par tition' or plate, .havingsa restricted orifice 2 is mounted in the intake conduit as shown. The

across the partition, when air is flowing through the conduit. A conduit connects thespace 26 in the cylinder behindthe piston with the intake conduit before the orifice, as shown. The conduit puts one side ofthe piston in communication with I the high pressure (inlet) side of, the orifice, while W the other side :of the piston is in communication with the, low pressure side of" the orifice: The

differential pressure across the orifice, andhence across the piston, will, be proportional tothe' square of. the velocityofthe fluid passing through theoriflce.; 2 i it second cylinder 30 ismounted in the mixing chamberasshown, in opposed relation to cylinder It. A piston ll attached as at to the other" end .Of-shaft is, is adapted to slide freely, but

withoutsuhstantial leakage, in cylinder 30. Fuel enters the cylinder on one side of thefpiston through a. fuel inlet conduit 33 and-inlet I4, and

section of a'modified I: by a blower or super-charger Fuel iss'upplied to inlet 31 under pressurejas froma pump or from an elevatedsource df supply, and enters the on the other side of the piston through an inlet 38. A partition 36 having a conical restricted orifice 31 is positioned in the fuel inlet line between inlets and 35, as shown. With this arrangement,. when fuel enters inlet 31 under pressure and flows across orifice '81 a differential pressure is set up acrosspiston 3| The differential pressure is proportional to the square of the velocity" of the entering flow of fuel. 7 A tapered pin 38 cooperating with orifice This provided I for regulatmg the differ ntial. pressure across" "the. orifice. I

The tapered pin is mountedon a threaded shaft means of a partition 41. An elongated nipple l0 is mounted on the end of theoylinder, projecting into themixing chamber as shownjand in communication'withthe' cylinder beyond partition H; The nipple is provided witha narr'ewb re l9. In operation, air flows into the mixingchamber through conduit Hand-valveand seat I4, I11

either under-engine suction or under pressure as mixing chamber throughoriilce 'IT, inlet 34, valve andseat ld-fand 15, and bore 48. In the air side of the carburetor, a'difl'erential" pressure is set up across orifice '24 and thejpressureon the right hand side of the orifice bein'g greater, pressure in space 26, in communicationwith intake valve and seat I! and I]. Atthe same time, a

l9: through conduit li ten'ds to force the piston'n to the left, partially closing'theair intake past 34 and '35 by means of orifice 31, and pressure to left of piston 31 'tendsto-rnove-the' piston to the right,'partially'closing the 'fuel fiow through valve and seat" I: and It}: According" to the invention the size of eylindersfitfand bforiiices 24 and I 31, and of the fuel an relative flows the tendency ofthfeair pistomunder differential 'pressure-in 'th'e air flow,- to move shaft' IS in one directiom-is exactly counter-balanced by the tendency oi'the fuel piston, under diflerenthe other opens untilthe opposing forces acting u N r'valves'isso proportioned that when fuel andfair are supplied under normal on the two pistons are equal; "at which time a I deflnit'eproport'idnal flow willlbe maintained. As'

a result, under normalconditions the coupled valves remainin a definite relative position such as that shown in'Fig l. Atthis time the differeritial pr'es sures in'the two flows and on the pistons arein general not equal. In the balanced positior 'fthejpressuifeson the' p'istons are only 1 equal when the two pistons are made'the same size. Butthe opposing forces exerted by the two pistons are equal and balancedf'l 'he tapered pin in the fuelline'permitsthediflferential fuel pressure across piston II to be adjusted; and hence the'relativeproportion'offuel and air.

If the'sucti'on in air intake conduit [l9flis increased, as by'an increase infei gin'e speed on opening the throttle, the pressure differential across orifice 24 will increase, increasing the pres sure-in space 26 and moving the piston 22 and 'hence shaft" 15 slisht lyto the" left." 'I'hiscuts *parts of the operating range. As shown, the dedown the air flow slightly and opens fuel valve, l3

slightly, thereby admittingmorefuel into the increased air fiow. I

Similarly, if the pressure in the fuel line increases, the fuel valve I3 will partly close and the air valve will open,.admitting more air and thus keeping the proportions constant. The throttle valve I2 allows the total combined flow to be regulated. I

This embodiment of the invention is well adapted for use in aircraft engines, whichfare ordinarily equipped with a fuel pump anda supercharger. The device dispenses with float bowls, vacuum tanks, etc., and is thus capable of functioning satisfactorily in any position. The fuel injection nipple is short and fine,-. bored? thus neither gravity nor suction in the air intake near the nozzle has any appreciable. effect on the rate of introduction'o'f fuel.

Instead of- partitions 23 and 36, venturis, Pitot tubes andthe like may be used,'with theproper connections, to control the operation of the pistons by differential'pressures. I I

2 represents a modified form of carburetingdevice in which the pistons-are replaced by'diaphragms. This construction presents some advantages in that diaphragms are 'free' from friction. As shown, the air side of the carburetor is similar to that in Fig. 1, except that piston 22 'is replaced by a corrugated, flexible metal diaphragm 55 fixed in the cylinder as at and centrally attached to shaft I5 as at 2i. On the fuel side, cylinder 30 is replaced by an injection nozzle 51 mounted in the mixing chamber as shown and'provided with a tapered orifice 58 cooperating with valve I3 as shown. The nozzle is in communication with a diaphragm chamber 59 containing a diaphragm 50 mounted therein as at GI and centrally attached to shaft I 5 at 32. Inlet 35 is in communication with one side of the diaphragm and inlet 34 with the other side. "The'restof the device of Fig. 2 is similar to 'Fig, 1. The operation is the same and requires no further explanation. I I v Fig. 3 shows a modified form of carbureting device having balanced valves, in which the throttling is effected by shifting the valve seats and which also has provision for changing the relative proportions 01' fuel and air in certain vice comprises a cylindrical mixing chamber III with flange II. The air side of the device comprises a cylinder 'Ill mounted on thev mixing, chamber as shown. A separator disk II having a circular orifice I2 is mounted in'the mixing chamber as shown, and a similar separator disk I3 having a-circular orifice I! is mounted in the. chamber below the first disk and adjacent the lower rim of' cylinder ID as shown.. A vertical cylinder 15 is positioned concentrically within of orifice 1| as at I5 and joining the upper disk II as at' 11. The air'valve is a balancedjvalve I9 mounted on a shaft attached as at 8| to a sliding piston 82 adapted to slide freely in cyl-' inder III. The piston is orificed as at 83: in this embodiment the differential pressure is established by means of orifices in the piston itself. The valve members I8 and I9 cooperate with two" conically orificed seat members 9|! and SI. These seat members are coupled together by means of a rod 92 as shown, and are adapted to slide in two cylindrical slides or ways 83 and 84. It is seen that the valves are in communication withan' I bodiments.

cylinder 15, the innerwall of. chamber I0, and.

separators I I and I3; and in communication with aninner cylindrical space 55 in the cylinder 15. Airpasses intothe mixing chamber through valve and seat I 8, and through valve and seat attached tea shaft I03 as at I0 4. Two discoid,

valve membersfIO S and I 05 are mounted on the annular space bounded by the outer wall ofj shaft as shown and cooperate with two sliding seats I01 and I08, which are coupled together by a rod IOSI The seatsare adapted to slide in cylindrical ways IIII and III which are mounted in a cylinder II 5 similarly to the arrangement of the air valves. Fuel is admitted to cylinder I00 through inle.t33.Valve shafts I03 and 80 are coupled or attached to .each other by a'bar IIS.

so that movement offeither shaft is directly communicated to the other shaft. The sliding seats,.

coupled by rods 92 and I09, are adapted to be moved from outside by means of a rotating lever I2 I pivoted in the walls of cylinder'l5 and the mixing chamber by a rod I22 and pivotally attached to rods 92 and was at I23 and I24. The outer-end of rod I22 carries an arm I25 adapted to be operated by throttle rod I26 as shown- Movement of the arm is thus communicated to rods 92 and I09 and allows the seats to be shi fted from outside, with respectjto the "discoid valve members.

In'operation when arm I 2I is in a certain position the valve seatsand the valve members are in a definite position, that-of the valve members being determined by the pressures infuel inlet 33 and air inlet cylinder 10 as, in the other .em-

Throttling is performed by moving arm I25. If the armis moved to the left for example, all the valve, seats are brought slightly nearer the valve members, throttling the flows,

of fuel and air. I As statedpit. is often desirable to provide for richer or leaner mixtures than are theoretically correct, in certain parts of the operating range. I I In 'Fig. '3' I haveshown how the device maybe modified to provide, this. As shown, a tapered or graduated pin Hill is mountedin cylinder IOILby means of the threaded rod I3I vcarrying a hen,-

dle I32 and cooperating with orifice I02 in piston II. The tapered pin, which is stationary with respect to the orific'e,'l02 is adapted to provide different effective orifice openings in different operating positions of the valve andpiston link- I:

' age. If the fuel fiow is, fcr example, under substantially constant pressure, as is the case when an ordinary vacuum tank fuel supply is used, and the air fiow varies according to the throttle the mixing chamber, as shown, joiningthe edge opening and engine speedythen different rates of air fiow will produce different effective orifice openings in the fuel piston, and hence the opencomprising two discoid valve members I8 and ing' 61' the fuel valvewill changej'in such a'wayf that difierent fuel-air proportions will be pro,-

vided for different air flows. The proportions" of fuel and air m ay be varied in any partoi the range by providing the tapered pin with alsuit able contour. InfFi'g. 3 the contour of the pin I is such that movement ofthe ,valve linkage to theleft under increasedair flow, cuts down the effective orifice at I02., The fuel pressure being creased air supplyth proportional fuel supply is slightly less than when a simple orificed pisassumed constant,,the result is that underina.

ton, without tapered pin, is used. Thus a slightly leaner mixture will be provided under increased air flow: at higher engine speeds. In some cases it is desirable to have the tapered pin almost cylindrical, thereby producing but slight change in proportioning in different parts of the operating range. In some cases it is found convenient to have the taper of the pin reversed; that is, the large base of the pin is on the right of piston H and the smallest sectionis to the left.

I haveshown cylinder 10 in communication with an air cleaner indicated "diagrammatically at I33. The use of an air cleaner'is desirable but is not essential.

The double valve arrangement shown for both fueland air flows is to provide balanced valves. In the air valve for example flow in one direc-.

tion through valve and seat 18 and 9.0 is balanced by flow in the opposite direction through valve 19 and seat 9|. Thus there is nodisturbing effect due to rush of air against thediscoid valve members.

lar. v V

In Fig. 4 I have shown a simplified form of charge forming or mixing device adapted for use with gas engines, or for general fluid proportioning. As shown, the device comprises a mixing chamber Ill in communication with an,

inlet cylinder I40 for one fluid and an inlet cylinder Ill for another fluid. Two conical valve seatv members It and II are mounted in the device by partitions I42 and 20 as shown. The valve assembly comprises two d'scoid valve members I and I mounted on the shaft l which is attached as at 32 to an oriflced piston H6 sliding in cylinder Ill and attachedat the other end as at 2| to an oriflced piston I" sliding in cylinder I40; The

operation of the device is sim'lar to that of Fig. 1.

For the sake of clarity the invention has been shown diagrammatically. In devicesconstructed according to the invention the various parts are proportioned tosuit the requirements of the installation for which the device isintended. The usual attachments for carburetors, such as choker valves, warmers etc, may be employed, these being omitted from the drawing for the, sake of simplicity. Also the pressure responsive means in each device may be diaphragms, multi-convolution bellows or pistons, and the means for establishing differential pressures for operating the.

pressure means may be of the oriflced partition, Venturi or Pitot tube type, as is convenient. The tapered pin valve in the fuel linecan be mounted in such a way as to allow it to be temporarily retracted from the valve seat by a hand lever or other control means, to provide a temporary increase of the fuel flow as during starting up.

What I claim is:-

1. Apparatus for mixing two fluids underpressure in constant relative proportion, comprising a conduit for each fluid, the conduits beingin communication, a valve in each conduit, means coupling the 'valves together, means separate from said valves for establishing a differential pressure in each fluid and means responsive to said differential pressure of each fluidand in operative connection with the valves.

2. Apparatus for mixing two fluids under pressure in constant relative proportion, comprising a conduit for each fluid, the conduits being in communication, a variable opening valve in each conduit, coupling means for the valves such that 1 motion of one valve towards closed'or open po- The fuel valve arrangement is simi-' valve towards open or closed position respectively,

means responsive to pressure of the fluid in each 3. In a carburetor for an internal combustion engine a conduit for fuel and'a conduit for air, a mixing chamber in communication with the conduits, "a variable opening valve for each conduit adapted to control flows therein,-coupling means for the valves, means separate from the valves for establishing a differential pressure in each flow, means responsive to said differential pressure of fuel and of air in operative connection with the valves. and means'for varying the total combined flow from the mixing chamber.

4. Apparatus for delivering a flowing mixture of fuel and air to an engine in definite relative proportion and in variable total flow, comprising a conduit for fuel and a conduit for air, a mixing chamber in communication with said conduits, a variable opening valve in each conduit, coupling means for the valves such that motion, of one valve towards closed or open position respectively imparts motion to the other valve towards open or closed position, respectively, means responsive topressure of the fluid in each conduit,

said pressurere'sponsive means being operatively v connected to the valve coupling means whereby increaseof pressure in either to partially close the valve in that conduit and to partially open the valve in the other conduit and means for varying the total combined flow from the mixing chamber.

5. In a carburetor for internal combustion engines a conduit for fuel and a conduit for air, a

mixing chamber in communication with the conduits and adapted to deliver into theintake of the engine, balanced variable opening valve means for each conduit adapted to control the flows therein, said valve means comprising a-pair of coupled movable members and a pair of seat members adapted to be shifted with respect to the valve conduit is adapted members and cooperating with the valve members, means for passing a flow in one directionthrough one of the valves andseats and in the opposite direction through the other of the valves and seats, coupling means for the valvemeans for each conduit whereby motion of one valve member toward closed or open position respectively imparts motion to the other valve member towardopen or closed position respectively. means responsive to pressure of the fluid in each conduit,

said pressure responslvemeans being operatively connected to the valve coupling means whereby increase of pressure in either conduit, is adapted to partially close the valve means for'that conduit and to partially open the valve means for the other conduit and .meansi'or shifting the; seat members with respect to the valves to provide throttling. H v

'6. In a carburetor for internal combustion engines, a mixing chamber, means for conducting a flow of fuel to thefmixing chamber, means in said conducting means. adapted to establish a differential pressure in the fuel flow, means for conducting a flow of air to the chamber, means in said conducting means adapted to establishxa differential pressure in the air flow, pressure-responsive means adapted to respond to the dinerential pressure in the fuel line andpressure-responsive means adapted to respond to the differential pressure in the air line, variable opening valve means in the fuel line and valve means in the air line, the valves being coupled together such that opening of one tends to close the other,

v the valves being operatively connected with the of either valve tends to close the other, the valves being operatively connected with the pressureresponsive means. s

' 8. In a carburetor for internal combustiorP-ensince a conduit for fuel and a conduit for air, a mixing chamber in communication with the conduits and adapted to deliver into the intake 01 the engine, a variable opening valve in the fuel conduit,means for establishing a diflerential pressure in the fuel conduit, means responsive to said difierentiai pressure in the fuel conduit and operatively connected with thevalve and adapted to reduce the opening of the valve on increase of differential pressure in the fuel conduit, means for establishing a differential pressure in the air conduit and means responsive to said differential pressure and operatively connected with the fuel valve and adapted to increase the openingof the valve on increase of differential pressure in the air conduit.

JOHN WEBB HOGG. 2o

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