US2801835A

US2801835A - Pressure carburetor

Info

Publication number: US2801835A
Application number: US347734A
Authority: US
Inventors: Leland B Read
Original assignee: ACF Industries Inc
Current assignee: ACF Industries Inc
Priority date: 1953-04-09
Filing date: 1953-04-09
Publication date: 1957-08-06
Anticipated expiration: 1974-08-06

Description

3 Sheets-Sheet )l N E NN b wm. ,m6 uhmm d m K a.. ,.3 fl nl INVENTOR. L ELANDA B. READ BY ATTORNEY rAllg- 6, 1957 L. B. READ PRESSURE CARBURETOR Filed April 9, 1953 HAMM..

Aug. 6, 1957 Filed April 9. 195s L. B. READ I PRESSURE CARBURETOR s sheetsshe'et 2 LELAND B. READ BY. M

ATTORNEY INVENToR.

Aug. 6, 1957 L. B. READ 2,801,835

` PRESSURE CARBURETOR Filed April 9, 1953 3 Sheets-Sheet 3 INVENToR. LELAND B. READ RY/@wf M ATTORNEY United States Patent i 2,801,335 PRESSURE CARBUnEroR Leland RMRed, Normandy, Mo., assignor, by mestre assignments, to ACF Industries; Incorporated, New Yoric, N. Y., a corporation of New Jersey peiianen Ajpiii 9, 1953, ssi-iai No. 347,734 11 claims. (ctms-51) tio'n` andeavsserri'bly d iiiiciilties.

ilseV lwidely recognized in the art that each engine requires acarbreto'r tailored to t its reqrements. Furwhich are readily interchangeable to eliminate producthermore, even individual models of the saine engine requi .mirror changers overl ,the` previous Vmodels Because 1S; th Pliblll of adequate supply and" replacement f, V l "'"dividiialmakes of car'bret'rsf becomes excessivelylarg Y i V e also v ll understood that present-day motor vehiclefneeds r` uir'ecarbnife'tolrswliich areirnrnune toviolent aiccelerations'A aiid` dceler-ations diie to" sharp turns and violent braking; e Heatl bowltype of `carbure"tor thus presents ma'iiy problems' in r to render it reasonably ,satisfa'etoiy ini performance to"` suit these conditions.

, A:ari 4object ofthis` invention to provide a` ucarburetoi' with asmny iiiterharigeable parts as possible to siinplify its` prddctidn.

It is also an abject or this invention to" prei/idea mechanism ,whicli; by substitute or interchangeable parts, may be readily adapted to different engine requirement-s.

Itiis also an object ofthis inventi'oill to provide a pressubie earbtiretei with* ft-throttle positioned te .wid icing effects i It isls'o ariobject of` this invention toprovide a carburetor with athrottleloperated fuel metering control which is modulated-to compensate for changes in load on the engine: l

It `i`s Ya further 'object of this invention to provide a 'carbiiretor of the pressure type wherein the spply of fuel is" directly controlled by throttle position, and wherein this mechanism is provided with a modulating means to supply fuel dining engine operation at idlespeeds.

In the drawings,

Fig; 1 is a front elevation of a carburetor according to this invention. i

Fig. 2 is a section on the line 2-2 of Fig. l. i

Fig. 3 is'a top plan View ofthe structurein Fig. 1.

Fig.` 4 is a section "on the line 4-4 of -Fig. 3. p

Fig. 5 is a` vertical section o f the carburetor shown Ain Figi 1; showing `the position of the parts at part-throttle.

Fig; 6 is a vertical section on `the line `6 6 ofFig. 5f.

Fig. 7 is ahorizontal sectionalview of the carburetor shown in Fig. 1, showing the position of the parts at deadidle position of the throttle.V w y ,l ,j

Fig. 8 is a sectional view on the `line `25e-t5 of Fig.

Referring `now to Figs. 1 A,and 3Fig. 1 shows a combined air hornor throttle body 1 which is `a separate piece fand, as such, can .be` readily prodiiced Ain various sizes so as to be Linterihangeableiri the carburetor assembly order to suit ,differentu engines. Thisthrottlebodryl has `tlang'es 2`provid`ed with stud holes 3 sultably positioned for 2,801,835 Patented Aug. 6, 1957 attichment t0 h`manf0ld of the particular engine for Whlh they, are designed. rA mixture conduit 4 extends vertically through the throttle body, and formed integral fherewithis a Venturi havingl a' throat 5. vOn the side of the throttle body is a threaded boss 6 which connects to a port in the mixture conduit. This connection is provided for the usual vacuum-operated spark advance.` Above the venturi is rotatably mounted a throttle shaft 7 carrying throttle valve 8, and also throttle-operated arm 9, which, in turn, has a connection 10 for the usual `manual control provided in the motor vehicle. Operating arm 9 has an upstandng lug 11 engaging one end of idle speed adjusting screw 12 threaded through lug 13 formed integral with the throttle body. e

Extending transversely of the mixture conduit adjacent the throat of the venturi 5 is a fuel nozzle 15 secured in the throttle body by a threaded connection 16. The nozzle has a metering passage and seat 17 which opens outwardly, and this opening is controlled by a metering rod 18 shown in seated position at 19 in Fig. 2. In this position the fuelnozzle is tightly closed. The metering rod 18 is slidably mounted in an aligned passage 20 in the opposite side `of the throttle body, and is operated by a mechanism which will be later described. To the right of the ,throttle body is removablysecured a fuel reservoir 21. This reservoir is sealed to the throttle body by a gasket 22 and attached in any suitable manner, prefen ably by cap screws 23. One side of the fuel reservoir has a threaded opening receiving seat 24 provided with a needle valve 25 and a threaded Vboss 26 for direct connection to a `fuel pressure source. The control for the needle valve includes a bell crank pivoted about the`pin 27 within the fuel reservoir which has a presser foot 28 engaging one endof the needle valve for urging it towards its seat. The opposite arm 29 engages within an opening 30 of a slidable plunger 31 guided in an opening in one wall of thefuel reservoir. This plunger 31 has an adjusting screw 32 carrying a lock nut 33 suitable to adjust the size of the opening within the plunger 31 to control the pressure within the fuel reservoir in a manner later described. Opposite the adjusting screw the plunger 31 has a threaded socket 34 which receives a stem 35; On the stem is a nut and washer assembly 36 which engages and clamps a `diaphragm 37 against the end of the plunger. A housing 38 surrounds the stem and has a flange portion 39 provided with suitable holes by which. cap screws 40 secure the housing to the fuel reservoir. The diaphragm 37 forms a seal between the fuel reservoir and the housing 38A. `Screw threads 42 are formed internally of the outer end iofhousing 38, and are engaged by corresponding threads on a combination `guide andabutment member 43. The guide has a suitable aperture'for receiving the outer end of the stem 35, and is adjustable Within the housing to vary the compression in spring 44. Pressure Within the reservoir acts on one side of diaphragm 37 through passage 45 While pressures posterior `the throttle act on the opposite side through passage 46.

O`n the opposite side of the throttle body is a housing 5d secured to the throttle body by a plurality ci cap screws 5l. Housing Sti and reservoir 21 are formed from iden-` tical die castings. The housing is suitably apertured at S2 to slidably support a plunger 53.` A socket 54U1n the plunger 53 receives one end of meteringrod 18. The rod is securely locked in the socket by suitable keepers 55, The opposite end of plunger 53 extends into a cup-shaped pocket 56 which is provided with a passage 57 communi-` eating between the socket and the housing. This end of the plunger has an internally threaded socket 58 threadedly engaging with stem 59. On this stem is arnut and washer assembly 60 which engages and clamps diaphragm 61 against 'one end of the p1unger A housing 62 sur,-

rounds .the stem 59 and is detachably secured to the housing 50 by a series of cap screws 63, and the joint between the two is sealed by diaphragm 61. One end of the housing 62 is internally threaded to receive a combination guide and abutment member 64 provided with a central aperture for the stem 59,. This provides an adjustable abutment for compression spring 65, which bears against the end of the plunger. Housing 62 and housing 33 are substantially identical, and are sealed with identical plugs 70 and 71. One side of diaphragm 61 is exposed to pressures within housing Si) through passage 57, while the opposite side of diaphragm 61 is exposed to pressures posterior the throttle 8 through passage 47. Pressures within housing t) will be near atmospheric because of leakage about countershaft 77.

The means of operating the plunger 53 from the throttle is best illustrated in Figs. 2 and 4.

Referring to Fig. 2, plunger 53 has a socket 75 which receives the ball end of a lever 7 6. The socket is slightly larger than the ball end to provide some lost motion for a purpose that will later be discussed. Lever 76 is rigidly secured to a countershaft 77 by a tapered piu 7S extending through the lever 76 and threadedly engaging a transverse passage in the shaft 77. This shaft is suitably mounted top and bottom in bearings 79 and titl, best shown in Fig. 4. Fixedly secured to the upper end of countershaft 77 is an arm 81. The outer end of this arm is threaded to receive an adjusting screw 82, which, in turn, bears against an abutment @3 of an actuating arm 84 rotatably mounted on the countershaft 77. A torsion spring 85 iixedly attached at 86 to the housing 50 is wound around the countershaft 77 and engages arm 81 to maintain engagement between the adjusting screw 82 and abutment 83. Throttle-actuating arm 9 is connected by way of a link S8 to a lug 89 on the outer end of actuating lever 84, so that, when the throttle is opened, rotation of the arm 9 will be transmitted to the actuating lever 84, and by abutment 83 to the arm 81 to rotate countershaft 77 against the tension of spring 85 to produce like movement of the ball-end lever 76 which will engage the outer side of the socket '75 and withdraw the stepped metering rod 1S from seating engagement within the metering orifice ll7. By means of the adjusting screw 82 the amount of clearance of the ball end and the plunger socket may be adjusted, and this expedient provides a control of the mixture at idle, since Vthe clearance just mentioned determines the amount of displacement of the metering rod from its seat by action of the suction on the diaphragm 6l. Thus, the permissible range-of movement produced by the diaphragm is controlled oy the amount of clearance between the inside face of the ball and the socket.

The fuel pressure, on the other hand, may be determined in two ways, either by adjustment of the set screw 32 or of the combination guide and abutment 42 to increase or decrease the effect of spring 44.

Operation lt will be apparent from the structure just described that movements of the throttle arm in an opening and closing direction will produce corresponding movements of the metering rod to increase and decrease the size of the metering orifice as required. This particular throttleactuating mechanism also provides for adjustment of the metering rod for proper mixture during engine idling conditions, as well as for fully sealing the discharge orifice 17 when the engine is at rest.

From the above description of the throttle'linkage, it will be understood that the connection between the throttle and the plunger is such that only opening movements of the throttle are directly transmitted to the plunger actuating the metering rod, and that some clearance exists between the ball end of the arm 76 and the sockel 7 5.

In the lirst instance, when the engine is at rest, there win be no suction imposed on the outer surface of the diaphragm 61. Consequently, compression spring 65 will hold the metering rod on its seat 17 to prevent the leakage of gasoline from the nozzle 15. When the engine is started, however, suction will exist on the outer side of the diaphragm 61 which will compress spring 65 slightly until one side of the socket 75 engages with the ball end on lever 76. This will crack the needle valve from its seat sutiiciently to provide enough fuel from the end of nozzle 15 for idle conditions. As the throttle is gradually opened, the stepped portions on the metering rod will provide the necessary increase in orifice size to properly meter the fuel for steady running.

This carburetor also incorporates not only modulation of the metering rod control as above explained, but also modulation of the fuel pressure in the reservoir to accommodate the requirements of the engine for enriched mixture during acceleration and heavy loads, as well as a leaner mixture for low load conditions on the engine. To accomplish these results, the carburetor has a fuel control which regulates the fuel pressure in the reservoir in accordance with suction acting on the outside of diaphragm 37.

Referring toFig. 7, the position of the parts corresponds with the conditions existing at idling speeds. From this figure it can be readily seen that the amount of opening of needle valve 25 is controlled by fuel pressure on one side of diaphragm 37 and suction acting on the other opposed by a predetermined resistance in spring 44. In this position, the valve is shown practically closed. Suction will be high, 'and fuel pressure low. At part-throttle, however, fuel pressure must increase to compensate for the drop in suction acting on this diaphragm. Consequently, the flow through the orice 17 will increase, not only due to the movement of the metering rod, but also due to this pressure increase in the reservoir. At high speed, suction acting on the diaphragm will be negligible. Therefore, the fuel pressure must increase a corresponding amount to the drop in suction. At any throttle position, however, should the engine load increase suddenly, suction will immediately drop to produce an increase in fuel pressure in the reservoir. Conversely, at any throttle position, if the load on the engine is decreased, suction will increase,

immediately lowering the fuel pressure within the reservoir a corresponding amount by closing the needle valve 25. lf the throttle is suddenly opened, suction will immediately decrease, thereby immediately stepping up fuel pressure. By this simple arrangement of parts, all of the necessary functions are performed. This carburetor will meter the fuel not only according to position of the metering rod and fuel pressure, but also according to the aspiration at the throat of the restriction, since this likewise will produce an increase in fuel flow at high rates of air llow. This carburetor, therefore, presents many possible variations in fuel flow by several distinct and separate means, since fuel ow may be controlled by aspiration, fuel pressure, or metering rod calibration. Thus a flow curve suitable for any type of engine may be obtained.

I claim:

1. A carburetor for a motor vehicle engine having a plurality of separately replaceable units comprising a rectilinear body, a mixture conduit in said body eccentrically located with respect to a transverse medial plane passing through said body parallel with the axis of said mixture conduit, a fuel nozzle in said mixture conduit 'symmetrically located therein-and parallel to said medial symmetrically ,arranged with respect Vto the transverse medial plane passing through said body and said hous- -ings and detachably secured in reverse relative position ascisse to opposite sides of said carburetor body whereby only one of said chambers is aligned with said fuel nozzle.

2. A carburetor having la mixture conduit, a fuel reservoir, a fuel nozzle in said conduit connected to said reservoir, a first means in said conduit including a throttle arranged for independently producing variable fuel pressures at said nozzle, and independently acting means for controlling the rate of fuel discharge from said nozzle, said rst means comprising a fuel pressure regulator having a progressively variable action to modulate fuel pressures at said nozzle in accordance with the combined action on said regulator of variable positive fuel pressures existing in said reservoir `and negative pressures posterior said throttle, and said independently acting means comprising a fuel metering means for said nozzle comprising a metering rod connected to said throttle by connecting means including a lost motion connection providing free limited movement of said rod from a normally closed position to an idling position within said nozzle when the throttle is closed, said throt i' tle acting through said connecting means to move said metering rod between idling and full open positions, and a modulating device operable responsive to suction in said conduit at engine idling speed to move said rod from its closed position to its idling position.

3. The combination defined in claim 2, wherein said means in said conduit includes a venturi device.

4. A carburetor for a motor vehicle engine, comprising a body including a mixture tube having a throttle and a fuel nozzle, a metering rod for said nozzle, a fuel reservoir for said body to supply fuel to said nozzle, and a control linkage for said rod actuated from said throttle, said control linkage including a lost motion connection operative throughout the range of throttle positions, said connection providing free limited motion of said rod between closed and idle positions when the throttle is in dead idle position, and a modulating device including a member connected to said rod and automatically operable to move said rod a predetermined distance from its closed position to its idling position for modifying the action of said control linkage through said lost motion connection as a function of engine suction at low engine speeds.

5. A carburetor for a motor vehicle engine comprising a body including a mixture tube having a throttle and a fuel nozzle, a metering rod for said nozzle, a fuel reservoir for said body to supply fuel to said nozzle, and a control linkage for said rod actuated from said throttle, said control linkage including a lost motion connection operative throughout the range of throttle positions, said connection providing free limited motion of said rod between closed and idle positions when the throttle is in `dead idle position, means to adjust the amount of lost motion in said connection, and a modulating device including a member connected to said rod and automatically operable to move said rod a predetermined distance from its closed position to its idling position for modifying the action of said control linkage through said st motion connection as a function of engine suction at low engine speeds.

6. A carburetor having a mixture conduit, a throttle and a fuel nozzle in said conduit, a venturi in said conduit, a fuel reservoir adjacent said conduit, a variable metering orifice between said reservoir and said nozzle whereby the pressure downstream of said orifice will vary as a function of engine speed and throttle opening, a metering rod in said orifice, a control linkage including a lost motion type of connection between said throttle and said rod, said connection providing free limited motion of said rod between closed and idle positions when the throttle is in dead idle position, a suction operated device actuated through a separate connection with said mixture conduit and separately connected to said rod, and a pressure regulator for said reservoir having a 6 connection with said mixture conduit posterior of said throttle for adjusting the fuel pressure upstream of said orifice as a function of engine load, whereby fuel metering is controlled exclusively as a function of manifold pressure when said throttle is closed, and by the variables of engine speed, throttle opening and manifold pressure in all open positions of said throttle, said `connection being operative throughout the range of throttle positions.

7. in a carburetor for an internal combustion engine, an air induction passage having a venturi therein, a throttle in said passage anterior said venturi, a fuel discharge nozzle to discharge fuel from a source of fuel under pressure into said venturi posterior to the throttle, a metering rod connected to `and actua-ted by said throttle and operable 4to vary the flow of fuel through said nozzle and movable between a closed position and a full open position responsive to corresponding movement of the throttle, resilient 'means yieldably resisting movement of said metering rod from its closed position toward its open position, and pressure responsive control means operable responsive to variations in pressure in said passage between the throttle 'and venturi, automatically operable to move said metering rod a'predetermined distance from its closed position to its idling position responsive only to engine suction at idling speed when the throttle is in `dead idle position, said control means comprising a suction chamber closed at one end thereof by a diaphragm connected to said metering rod.

8. .ln a carburetor for an internal combustion engine, an air induction passage having a venturi therein, a throttle in said passage anterior said venturi, a fuel discharge nozzle to discharge fuel from a source of fuel under pressure into said venturi posterior to the throttle, a metering rod connected to and actuated by said throttle and operable to vary the flow of fuel through said nozzle and movable between a closed position and a full open position responsive to corresponding movement of the throttle, resilient means yieldably resisting movement of said metering rod from its closed position toward its open position, and pressure responsive control means operable responsive to variations in pressure in said passage between the throttle and venturi, automatically operable to move said metering rod a predetermined distance from its closed position to its idling position responsive only to engine suction at idling speed when the throttle is in dead idle position, said control means comprising a suction chamber closed at one end thereof by a diaphragm connected to said metering rod, and connecting means interconnecting said throttle and metering rod providing free limited movement of said metering rod relative to the throttle when the latter is in dead idle position.

9. In a carburetor for an internal combustion engine, an air induction passage having a venturi therein, a throttle in said passage anterior said venturi, a fuel discharge nozzle to discharge fuel from a source of fuel under pressure into said venturi posterior to the throttle, a metering rod connected to and actuated by said throttle and operable to vary the flow of fuel through said nozzle and movable between a closed position and a full open position responsive to corresponding movement of the throttle, resilient means yieldably resisting movement of said metering rod from its closed position toward its open position, and pressure responsive control means operable responsive to variations in pressure in said passage between the throttle and venturi, automatically operable to move said metering rod a predetermined distance from its closed position to its idling position responsive only Y to engine suction at idling speed when the throttle is in dead idle position, said control means comprising a suction chamber closed at one end thereof by a diaphragm connected to said metering rod, and connecting means interconnecting said throttle and metering rod providing free limited movement of said metering rod relative to the throttle when the latter is in dead idle position, said connecting means including a lost motion connection movable 7 with said metering rod responsive to movement of said throttle toward its full open position.

10. In a carburetor for an internal combustion engine, an air induction passage having a venturi therein, a throttle in said passage anterior said venturi, a fuel discharge nozzle to discharge fuel from a source of fuel under pressure into said venturi posterior to the throttle, a metering rod connected to and actuated by said throttle and operable to vary the ilow of fuel through said nozzle and movable between a closed position and a full open position responsive to corresponding movement of the throttle, resilient means yieldably resisting movement of said metering rod from its closed position toward its open position, pressure responsive control means automatically operable to move said metering rod a predetermined distance froni its closed position to its idling position responsive only to engine suction at idling speed when the throttle is in dead idle position, said source of fuel under pressure comprising a fuel chamber having an inlet controlled by a valve, and another pressure responsive control means to operate said valve to control the flow of fuel through said inlet into said fuel chamber. l

l1. In a carburetor for an internal combustion engine, an air induction passage having a venturi therein, a throttle in said passage anterior said venturi, a fuel discharge nozzle to discharge fuel from a source of fuel under pressure into said venturi posterior to the throttle, a metering rod connected to and actuated by said throttle and operable to vary the flow of fuel through said nozzle and movable between a closed position and a full open position responsive to corresponding movement of the throttle, resilient means yieldably resisting movement of said metering rod from its closed position toward its open position, pressure responsive control means automatically operable to move said metering rod a predetermined distance `from its closed position to its idling position responsive only to engine suction at idling speed when the throttle is in dead idle position, said source of fuel under pressure comprising a fuel chamber having an inlet controlled oy a valve, and another pressure responsive `control means operable responsive to variations in pressure in said passage between the throttle and venturi to operate said valve to controlrthe How of fuel through said inlet into said fuel chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,996,590 Rockwell Apr. 2, 1935 2,232,392 Kittler Feb. 18, 1941 2,269,277 Lichtenstein Jan. 6, 1942 2,297,550 Gistucci Sept. 29, 1942 2,316,327 Garretson Apr. 13, 1943 2,328,604 Bicknell Sept. 7, 1943 2,457,765 Winkler Dec. 28, 1948 2,711,885 Moseley et al June 28, 1955