US1797165A - Carburetor - Google Patents

Description

:.March 17, 1931. l P. s. TICE 1,797,165

GARBURETOR m Filed Sept. 18, 1926 2 Sheets-Sheet LL Z l rCzZ/Z A571? Ce.

March 17, 1931.

P. S. TICE CARBURETOR Filed sept. 18, 1926 2 sheets-shet 2 G56 on Figure 5. i

Patented Mar. 17, 1931 UNITED STATES i PERCIVAL S. TICE; 0F CHICAGO, ILLINOIS CARBURETOR Application led September 18, 1926. Serial No. 136,251.

The purpose of this invention is to provide an improved construction of a carburetor for internal combustion engines particularly adapted for producing and maintaining the fuel mixture properly proportioned for economy in the ordinary running of the engine both under load and idling, and also adapted to afford prompt acceleration upon change of the throttle opening from idling position or `for increased speed at any stage.

It consists in the elements and features of construction ,shown and described as indicated in the claims.

In the drawings:

Figure l is a side elevation of an engine equipped with a carburetor embodying this invention for indicating the relative position and mounting of the carburetor with respect to the engine intake manifold. f

Figure 2 is a section of the carburetor. on line 22 in Figures l, 3, and 5.

Figure 3 is a section axial with respect to the fuel mixture conduit of the carburetor, the float bowl or level-governing chamber being partly broken away. i

Figure 4 is a top plan view of the carburetor detached from the engine.

Figure 5 is a staggered section as at the line 5-5 on Figures 2 and 4. y

Figure 6 is a staggered section at the line Figure 7 is a detail section at the line 7-7 on Figure 6.

` Specific means for eil'ectmg the purpose of the im intion above stated consists in theV employment of two diaphragm pumping devices for injecting excess fuel for acceleration, one of said pumpmg devices belng actuated automatically upon and vby means ofv the change of pressure at the engine intake beyond the throttle resulting from change of throttle opening; and the other being actuated by mechanicah connection with /the throttle or throttle-adjusting connections, these two pumping devices being brought into action separately or together according to the conditions calling for acceleration, and the rate or degree of acceleration wanted.

In my Patent No. 1,575,877, dated March 9, 1926,-I have shown an automatically actuof effective fuel content in the tion of vthe* liquid fuel valve plate itselfat all positions except wide ated diaphragm for controlling the opening of a passage for an auxiliary fuel supply for acceleration, said diaphragm havingino pumping function. In my pending application Serial No. 16,897, filed March 20, 1925, I have shown the Y like diaphragm, i. e.,

automatically actuated, having the added i function of pumping the auxiliary fuel supply, i. e., forcing it into'the fuel mixture conduit for enriching the mixture. The present invention in one phase of it is diiferentiated from previous constructions in the provision kof an additional diaphragm connected for mechanical actuation for pumping auxiliary fuel. For understanding the principle and mode of operation of the present invention, it should be vborne in the mixture for steady running, that is, for fuel economy as distinguished from the development of maximum power, is compara- F tively lean, accelerating fuel must be supplied Whenever the intake pressure vrises appreciably, as upon increased throttling open-- ing .or upon increased load slowing down the engine. consists in the reduced rate of vaporization at higher intake pressures however caused, and at greater throttling opening, Independently of the higher pressures resulting from the greater throttling opening; and the practical problem to be solved is maintenance fuel mixture in the face of Vaporization rate reduced by either or both of these causes. The vapor.-

ization rate is affected inversely by the change of pressure on the fuel, and other things being equal varies inversely-as to p ressure. by the -fineness of thespraying or atomizaand since the throttle open throttle, constitutes the major construe# tion in thepath of the injected fuel, and thereby, the means of spraying and mechanically atomizing the jetted fuel, 'its actual physical positioninI the passage strongly. affects the degree of atomization The primary reason for this need k mind that in general, if D The vaporization rate. isaffected also l which it controls and therefore the rate of vaporization of the fuel. y

In general, therefore, a greater opening of throttle means both a higher presssure of the fuel at the engine intake and also a reduction Y of atomization of the fuel by spraying. Both these conditions,`intake pressure and 5 atomization,-are affected by the speed 0f the engine, in that at lower engine speed the intake pressure may be high with throttle so nearly closed as to have a high measure of effectiveness as a spraying or mechanically' w atomizing means. VFor this-consideration it will be clear that at lower engine speeds the L vaporization-rate is maintained at higher tineness for a given intakepressure than, at higher speeds, because of the osition of the throttle relatively favorable or mechanical atomization by spraying. And it follows that since the vaporizaton rate is then higher, less extra or auxiliary fuel needbe supplied i in order to maintain or produce the richness of fuel .mixture necessary or desirable for a given change in the intake pressure at the lower as compared with the higher rate of speed. l

Since the automatic or pressure-actuated diaphragm pump operates proportionately with the pressure changes without regard to the throttle position, and since a pump mechanically actuated by or from the throttle spindle must operate without regard to the pressure changes, .it is clear that neither one alone can be made to serve the requirements to best advantage. The automatic pump, if made of suflicient capacity to deliver the maximum quantity of fuel required upon full acceleration (that is, with wide open throttle), will deliver to'o much on partial open- -ing of the throttle; and the mechanical pump, if of the same total capacity, would deliver to little fuel on partial opening of the throttle.

These considera-tions and experimental work based upon them ,have resulted in a `combination in the present construction of thetwo types of pump device indicated, in which the best possible compromise ,is believed to have been attained with the automatic pump of a. capacity equal to one-half -or slightly less than one-half of the total full acceleration or requirement, the remainder being delivered by a mechanically actu- 'ated pump discharging proportionately to .the angular movement ofthe throttle spindle or degree of opening of the throttle valve.

`The structure shown in the drawings com- .prises a fuel mixture conduit indicated-at 10,

level-governing chamber or ioat bowl 'indicated at r12, and two diaphragm chambers (hereinafter referred to as variable pressure chambers) 15 and '16, all formed, except as to closure caps and fittings, in a single integral casting, in which the fuel mixture conduit, 10, is substantially vertical, the casting being provided at the upper endof said conduit with suitable flange, 10, for securing it at the entrance of the intake manifold of the engine in a familiar manner. The fuel mixture conduit, 10, fis of Venturi form having the aircinlet at the lower'end and havingmounted in its upper end portion a throttle valve, 11; The level-governing chamber,

12, is formed iIi the casting open at the left f. hand side, being closed in the nal construction by a cap, 13, in which there is formed the fuel inlet shownfat 13a, controlled by the valve, 13b, operated by the float, 13,pin the customary construction of carburetor ,float bowls or level-governing chambers. The said chamber, 12, i`s situated alongside of the lower or entering end portionbf the fuelmixture conduit, extending up alongside of of this carburetorit is constructed with three substantially independent fuel passages leading from the level-governing chamber, which constitutes the immediate fuel source, for discharge into the fuel mixture conduit, 10, said discharge of all three of the passages being substantially at the flow-accelerating constriction or throat of the venturi, and as shown, through the same jet port or nozzle.

The first to be described of these fuel passages will be referred to as the principal fuel passage which may be traced in the drawings from the level-governing chamber, 12,'to the passage at the Venturi throat, as comprising the metering orifice, a, in the metering plug,

2Q (see Figure 3) ,the bore, 21, extending longitugllnally with respect to the fuel mixture conduit, and a transverse bore, 22, discharg- Ying in he Venturi throat at the jet port or nozzle, 23, as seen in Figure 3. The second of these fuelfpassages, which will be referred to as the secondary passage may be traced 'from the level-governing chamber, 12, as com- -prislng the port, (see Figure 2), opening intothe passage, 31, from which the port, 32,

in the inner endy of the sleeve, 33, leads through said sleeve to the port, 34,'opening laterally therefrom into the variable capacity chamber, 15, bounded by the diaphra m, 17a, fromwhich variable capacity cham er the port, 35 (see Figure 6), leads to a check valve chamber, 36, which opens by a port, 37, into a bore, 38, which intersects thebore, 22, and

for. discharge at the jet port or nozzle, 23. This secondary passage has an additional connection at its initial part for leading from the level-governing chamber to the variable capacity chamber, 17, consisting in the metering orifice, 30a, formed in the'metering plug,

p trolled-passage, 40, in the metering plug, 40a,

which leads into the variable capacity chamb er, 16 (see Figure'2 and Figure 6), from which chamber the passage leads by way of `the port, 42, into check valve chamber, 43,

which at the opposite side ofthe check valve,

43, opens into the bore, 38 (see Figure 6 and Figure 7), which intersects the bore, 22, for

discharge at the jet port or nozzle, 23.

The specific purposes and mode of operation of .these different fuell passages will be hereinafter explained.

For two distinct purposes there is provided a passage @leading from a point in the fuel mixture conduit beyond the seating position of the throttle valve, 11, comprising (see Fig-V ure 3) a port, 50, and a bore, 51, into which it leads. For one of the purposes which it is provided this bore, 51, intersects the bore, 52, p which leads to a reduced bore, 53, which communicates with the bore, 22, of the principal v rfuel supply passage. The bore, 52, is formed through a boss, a, for mounting a needle valve,

60, whosel tapered terminal seats at the-entrance to the reduced passage, 53, said valve being provided exteriorly with a handle, 61, for manual operation and with a check device, 62, for retaining it at any desired position of adjustment for controlling the degree of opening of the needle valve. For a second purpose of the passage, 51, it communicates with a bore, 64, which intersects the bore, 52, back of the seat of the needle valve,

60, said bore, 64,1eading by way of a bushing,

, (see Figure 6) through the diaphragm,

. 17 a, which constitutes the movable wall of the variable capacity chamber,415, into the chamber, 17 f, formed in the diaphragm-securing cap, 17, hereinafter referred to as a pressure chamber.

llt. will be unders ood that the several bores formingby their intersections the continuous passages described, from ,the level governing chamber to the points of discharge in thefliel mixture conduit, are formed so as to thus in-l terseot and connect for continuity, by boring shown in the drawings and requiring no detail iin from convenient points in the exposed surface of the castingin the proper directions for thus meeting and intersecting, the outer ends of the bores being' closed by suitable plugs as description 'in order to be understood. 'One function of the passage, 51, leading from beyond the throttle valve to the dischange bore2 22, of the principal fuel passage, is the famihar one of constituting an idling by-pass for )fuel which will be drawn by engine suction throu h said duct,.51, when the throttle valve is adjusted at idling position,-

nearly closed,-the supply thus drawn, which is limited by 'the Vadjustment of the needle valve, 60, suicingffor keeping the engine,

running idle pr under light load. l` In tle present construction without defeating or in any manner or degree interfering with this function, thepassa e, 51, is'utilied by means of the intersecting ore, 64,- for an independ? ent function, namely, admitting lor transmitting pressure of varying degree to the pressure chamber, 19, for operating the dia.- phragm, 17a, which constitutes the movable wall of the variable capacity'chamber, 15, for reducing the capacity of that chamber for the' purpose of ejecting fuel therefrom through the passage leading from it and discharging in the fuel mixture conduit, in addition to the normal fuel supply discharged simultaneously at thesame point derived through the metering plug, 20, and bore, 21, drawn by the suction'opeating. directlythrough the fuel mixture condu'it at the Venturi throat. This action occurs when the engine, having been idling or running under light load or at relatively low speed, the throttle opening is increased for starting the vehicle from rest or for increasing speed. Such increased opening of the throttle causes increased pres'- sure in the intake passage immediately beyond the throttle, which increased pressure operating on the diaphragm, A17, forces 4it inward with respect to the chamber'15; or, as the action might be described, thei diminished suction permltsthe spring, 25, which is positioned for acting on the diaphragm in the direction for contracting the chamber, 15, to act with less lrestraint for reducing the chamber, 15; and that chamber being normally full of liquid fuel because it is wholly below the governed -level (indicated by the line,

' in Fig. 4) of the level-governing chamber, 12, forces liquid fuel in a jet through the port, 23, into thefuel mixture conduit, mo-

mentarily enriching the mixture and causing instant'and momentary4 acceleration of the engine'. This effect, it will be understood, lasts only for'the periodduring which the pressure-above the throttle valve is increasing; and the diaphragm, 17,.coming to rest at the somewhatradvanced lposition which causes reduced capacity of the chamber to the extent ofthe amount of fuel ejected, the fuel Vmixture proportions will return tol the normalas determined by the construction in respect to dimensions and arrangement 'of th Venturi passage and principal supply duct.

The passage, 51, withits connection at 50 beyond the'throttlefbeside the function already described, ,serves incidentally a third 53, through which the duct, 51, communicates as described with the fuel passage, 21,

22, just before the passage at 23 into the fuel mixture conduit, namely, that upon increase of pressure at 50 resulting from the opening of the throttle after the engine has been idling the fuel which has been drawn into the passage, 51, during idling is forced back and discharged in a jet through the reduced port, 53, with an aspirating effect su plying-in stantly, and in the interval Whicli will lapse before the supply would normally come through the passage, 21, 22, and the port, 23, the added fuel required to maintain fuel mixture at proper richness for operating the engine running with open throttle.

The purpose of the third or auxiliary fuel passage describedv is to afford an auxiliary jet of fuel to be delivered by action of the diaphragm, 188,in the same manner as the fuel jet is delivered through the secondary passagexby the action-of the diaphragm, 17 a,

the diaphragm pressure for delivering the jet to the auxiliary passage being produced by mechanical connection from' the throttle valve, this connection being such as to operate the diaphragm for pressure upon the movement of the throttle valve from a predetermined closed or partially open position for a predetermined istance and through a predetermined angle or distance of opening.-

Specically, the desirable construction is that the diaphragm is operated for following up the initial movement of the throttle valve from idling position (closed or nearly closed) for a fraction only of full opening. The construction for this purpose consists in providing at `one protruding end of the throttle valve stem', 80, a cam, 81, whose cam protrus`ion, 81a, cooperates with the terminal abutment, 82` of a` lever, 82, fulcrumed at thev upper corner ofthe cap, ,18, of the diaphragm chamber, 16, and having at its lower end an abutment, 82", operating against the protruding end of the stem, 18, of the diathrough the duct, 22, for discharge at the port,

23, into the fuel mixture conduit atthe Venturi throat.

The specific construction of the parts through which the secondary fuel passage is formed leading from the port, 30, to the vari-able pressure chamber, 15, comprising the sleeve, 33, having the valve port, 32, 'cooperating with the valve,v 32a, positioned within the sleeve, ,is for a specific purpose fully set forth in my co-pending application SerialNof 16,897, filed March 20, 1925, and

'need not be further described here beyond pointing out that the sleeve, 33, is pressed into contact with the diaphragm, 17a, for movement therewith, the valve, 32, being seated, not by its own movement, but by the movement vof the sleeve, and that this valve is held in position longitudinally by the thrust of the spring, 33d, reacting for thrusting it in the direction for seating at the port, 32, the valve being stopped as to movement'in that direction by a screw, 33?, which is set through the neck, 14, and is suitably adjusted in the vassembling of the structure to determine the distance of movement of the diaphragm, 17 a,

from normal rest position shown in Figure 2 necessary to seat the Valve, 32a; and it will be seen that in further movement of the diaphragm in that direction the valve will be withdrawn with the sleeve while held seated by the spring. The reason for providing two paths for the liquid from thechamber, 12, to the variable pressure chamber, 16, 011e through the port, 30, and the subsequent passages mentioned` and the other through the metering plug, 23, is fully set forth in my co-pending application and is not a part of thenpresent invention and need not be further stated here.

It will be obvious that means for mechanically, at will, operating the diaphragm, 18, may be substituted for the cam-connection with the throttle valve, and my invention in respect to auxiliary fuel supply at will is not limited to means for causing it associated with the throttle Valve adjustment.

I claim:

1. In a carburetor and the likegfor an internal combustion engine incombination withA an air and fuel mixture conduit adapted to be connected for discharge at the engine intake, a throttle valve in said conduit; a levelgoverning chamber constituting an iinme- (hate source of l1qu1d fuel, and a principal fuel supply passage leading therefrom for` discharge in the fuel mixture conduit anterior to the throttle valve, comprising in its course a liow restricting means and another fuel passage leading from the level-governing chamber for like discharge, and intermediately by-passing said How-restricting means of the principal fuel passage and a third fuel passage also leading to like discharge; variable capacity chambers interposed in and constituting a part of said second and thirdfuel passages respectively, having movable Walls for varying their capacity;

l-mechanical connections` from the throttle connections from beyond the throttle for acf tuating the movable Wall of the variable capacity chamber in the other of said additional fuel passages.

2L In a carburetor and the like for an internal combustion engine in combination with an air and fuel mixture conduit adapted to be connected for discharge at the engine intake; a throttle `valve in lsaid conduit; a level-governingchamber constituting an immediate source of liquid fuel and a principal fuel supply passage leading therefrom for dlscharge in the fuel mixture conduit; a sec- 4 ondary fuel passage leading from the fuel source for discharge in said conduit, a`variable capacity chamber interposed andconstitutingapart of said secondary passage intermediate the fuel source and the discharge'of said passage in the fuel mixturel conduit; means for restricting. the flow through said secondary passage toward said variable capacity chamber, the capacityvarying means comprising'a movable Wall of said chamber, a pressure chamber opposite -said Wall and a. pressure duct sleadin from a point in the fuel mixture conduit beyond the throttle valve to said pressure chamber, whereby increase of pressure in the engine intake passage beyond the throttle valve tends to reduce said variable capacitychamber and impel fuel therefrom through said secondary passage for discharge in the fuel mixture conduit, a check valve intermediate said va-- riable capacity chamber and the discharge of said passage, opening in the directionfor such discharge and seatingin'the opposite direction; an auxiliary fuel "passage leading from the fuel source for discharge in the fuel mixture conduit, comprising a second variable capacity chamber having fgr varying its capacity a movable wall, and operating connections from the throttle valve for moving said wall in the direction for reducing the capacity of said chamber for forcing fuel through said auxiliary passage forl discharge in the fuel mixture conduit upon movement of the throttle valve for a predetermined distance froml a predetermined idling position, and a check valve in said auxiliary passage seating in the direction'for preventing back- 'loW from the variable capacity chamber upon movement of said Wall for increasing the capacity of said chambem 5 3. In a carburetor and the like for an internal combustion engine in combination with 'an air and fuel mixture conduit adapted to be connected for discharge -at the engine intake; a throttle valve in said conduit; a level-governing chamber constituting an imi mediate source of liquid fuel and arprincipal fuel supply passage leading therefrom lfor discharge in the fuel mixture conduit; -a secondary fuel passage leading from the fuel source for discharge in said conduit, a variable capacity chamber interposed in and constituting a part of said secondary passage intermediate thefuel source and the discharge of said passage in the fuelvmixture conduit; means for restricting the flow throughtsaid secondary conduit toward said variable capacitychamber, the capacity-varying means comprising a movable Wall of said chamber, a pressurechamber opposite said Wall and a pressureA duct leading from a point in the fuel mixture conduit beyond the throttle valve to said pressure chamber, whereby increase of pressure in the engine intake passage beyond the throttle valve tends to reduce said variable capacity chamber and impel fuel therefrom through said secondarypassage for discharge in the fuel mixture conduit, a check valve intermediate said variable capacity chamber and the discharge of said passage, opening in the direction for such discharge and seating inJthe opposite direction; an auxiliary fuel passage leading from the fuel source for discharge inthe fuel mixture conduit, comprising a second variable apacity chamber having for varying its capacity a movable Wall, and operating 'connections from the throttle valve for moving said Wall in the direction Jfor reducing the capacity of said chamber for forcing fuel through sald auxiliary passage for discharge in the fuel mixture 'conduit upon movement of the throttle valve in the direction for increased opening.

4. A fuelmixture forming and delivering device for an internal combustion engine,

a point of discharge in the fuel mixture conduit anteriorto the throttle; a duct extending from a point in the fuel mixture conduit beyond the throttle valve to a point of communication with said fuel passage immediately preceding the' discharge of the latter into the fuel mlxture conduit, said last mentioned duct being reduced to form a jet at its discharge; whereby said duct serves upon increase of throttle opening after closure to idling position as a'gas pressure duct'for' delivering an as irating jet into the f uel passage substantia ly at its discharge into thc fuel mixture conduit, the fuel passage mentioned being a principal fuel supply passage;

an auxiliary fuel passage leading from the fuel source for discharge in the fuel mixture conduit through the'final discharge portion of said principal fuel passage; a variable ca pacity chamber having a portion of its enclosing Wall movable for varying its capacity and connections from said throttlel valve operating means for moving said wall upon movement of the throttle' valve in -the direction for opening, whereupon uponv such opening movement an accelerating jet of fuel is driven through said auxiliary passage exposed to an aspirating jet delivered through the pressure passage.

l 5. In a carburetor and the like forv an internal combustion engine in combination` With an air and fuel mixture conduit adapted to be connected for discharge at the enL gine intake; a throttle valve in said conduit; a level-governing chamber constituting an immediate source of liquid fuel, and a principal fuel, supplyp'assage leading therefrom for discharge in the fuel mixture conduit; a secondary fuel passage leading from the fuel source for discharge in said conduit; a variable capacity chamber interposed in and constitutingr a art of said secondary passage intermediate the fuel source and the/y disch-argeof said passage Jin the fuel mixture conduit, the capacity-varyingv means comprising a-movable Wall of said chamber7 a pressure chamber opposite said Wall and a` pressure duct leading from a point in the fuel mixturey conduit beyond the throttle valve to said pressure chamber, whereby increase of pressure in the engine intake passage beyond the throttle valve tends to reduce said variable capacity chamber and impel fuel therefrom through said secondary i passage for *discharge in the fuel mixture conduit, a check valve intermediate said variable capacity chamber and the discharge of said passage, opening in the direction for such discharge and seating in the opposite direction; an auxiliary fuel passage leading from the fuel source for discharge in the fuel mixture conduit, comprising a second variable capacity chamber having for varyv ing its capacity a movable wall, and operatlng, connections from the throttle valve for movlng said wall in the direction for reducing lthe capacity of said chamber for forcing fuel throughV said auxiliary passage for disl'charge in the fuel mixture conduit upon movement of the throttle valve for a predetermined distance ,from a predetermined idling position, and a check valve in said auxiliary passage seating in the direction forpreve-nting back-flow fromA the variable charge -ofsaid passage in the fuel mixture conduit, the capacity-'varying means comprising va movablegwall of said chamber, a

pressure chamber opposite said 'Wall and a pressure ductfle'adin-g from a point in the -fuel mixture'con'duit beyond the throttle valve to 'said pressure chamber, whereby increase of "pressure in the engine intake pasduce said" vvariable capacity .chamber and 'sage beyond 'the throttle valve tends to reimpel fuel-therefrom through said second-- ary passage for discharge in the fuel mixture conduit, a check' valve intermediate said variable capacity chamber, and the discharge of said passage, opening in the direction for such discharge and seating in the opposite direction; an auxiliary fuel passage leading from the fuel source for discharge in the fuel mixture conduit, comprising a second variable capacity chamber having for vary- -ing its ycapacity a novablewall,- and opercapacity chamber upon movement of said i Wall for increasing. the capacity of said chamber. y

6. In a carburetor and the like for .an internal combustion engine in combination with an air and fuel mixture conduit adapted to `be connected for discharge at the engine intake; a throttle valve inysaid conduit; a level-governing chamber constituting an immediate source of liquid fuel and a principal fuel supply passage leading therefrom for discharge in the fuel mixture conduit; a

' secondary fuel passage leading from the fuel source for discharge in said conduit, a' variable capacity chamber interposed in and constituting a part of said secondary passagel intermediate the fuel source andthe dis#

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