US2315052A - Carburetor - Google Patents

Description

Passed Mar.' 30, 1943 *UNITED' STATES PATENT OFFICE;

CARBURETOR George R. EricsonyKirkwood, Mo., assignor to Carter Carburetor Corporation st. Louis, Mo., a corporation of Delaware Application June 11, 1940, Serial No. 339,905 8 Claims. (c1. 261-83) This invention relates to carburetors for internal combustion engines and more particularly concerns novel fuel metering and atomizing I mechanism therefor.

It is an object of the invention to provide new and improved means for metering the fuel so as to introduce the correct amount of fuel into the air stream over a wide range of air velocity. It is a further object to insure the co-mingling of fuel as it aspirates into the air stream so as to produce a thoroughly homogeneous mixture at extremely low velocitiesias well as at'othe'r times.

Other objects and advantages will appear upon reference to the following detailed description and accompanying drawing referring to which:

Fig. l is a diagrammatic representation of a carburetor embodying a form of the present invention. The view corresponds to a sectional elevation, and some. conventional features of present day carburetors are omitted as they'are well understood and have no direct bearing on the present invention.

The reference numeral I indicates the main body memberof a carburetor which has a flange 2 at its lower end by means of which it may be attached to the intake manifold of an internal combustion engine. A'mixturepassageway 3 is formed throughfthemain body member and an adjacent fuel chamber 4 is formed integral there with. A main air inlet is indicated at 5, being formed in a combination air inlet and fuel chamber cover member 6. The member 6 is firmly attached to the main body member I by any suitable means (not indicated) and a sealing gasket 1 is provided therebetweem A conventional float 8 pivoted at- 9 acts upon a fuel inlet valve ID to maintain asubstantialiy constant level of fuel in the chamber 4 as indicated by the dotdash line AA. An atmospheric vent to the fuel chamber is indicated at I Y The fuel mixing conduit 3 is provided with a Venturi form constriction I2 and the lower or' outlet end of the mixing conduit is controlled-by a butterfly type throttle valve I3 mounted for rotation with a shaft l4. concentrically disposed within the upper portion of the mixing conduit and supported therein by transverse ribsI5, is a circular member I6 having a frusto conical shaped discharge basin I1 formed therein. Extending upwardlythrough the basin I! to approximately the level of fuel, is a stationary discharge nozzle IB. The upper rim of basin I1 extends toa point somewhat above the level of fuel. The mixing conduit is further provided with an annular recess I9 surrounding basin ll.

A rotary member 22 having a frusto conical shaped lower end is suspended in basin I I by means of a shaft 23 in such manner as to leave an annular space 24 between the rotary member and the basin.

Shaft 23. carries a turbine 25 keyed thereto. The shaft 23 is driven by an electric motor 26 supported on a spider 21. 22-is provided with outwardly and upwardly extending passages 220 which are directed toward the upper open end of annular recess I9. Member 22 is further provided with a tapered vertical bore forming a chamber 28 and receiving nozzle I8. The lower end of this tapered bore is made somewhat larger than the diameter of nozzle I8 to permit fuel to flow from basin I! to chamber 28. Fuel is supplied to nozzle I8 from fuel cham-- ber [through passage 30, chamber 3| and passages and 33a. Passages 20 in ribs I5 and cross holes 32 near the base of nozzle I8 permit the flow of fuel'from recess I! to nozzle 18. Under static conditions the recess [9, the basin I1 and the nozzle I 8 are fllled with liquid fuel to the level of line AA. It will be noted that the.

open end of recess I9 is above the upper edge of basin I1.

Fuel for idling operation is supplied to the;

mixing conduit through an idling system which comprises a passage 34 branching from passage 33, an idling'jet tube 35 having a metering orifice 36' at the lower end thereof, passages 31,38 and 39 and a discharge port 40 which opens into the mixing conduit near the upward opening edge of throttle II. A calibrated air bleed 4| to passage 31 is provided. Fuel for all operation is metered through a calibrated restriction 42 situated at the lower end of passage 33. The net opening of orifice 42 is made variable by the provision of a variable diameter metering rod 43 arranged for longitudinal adjustment with respect to said orifice. The metering rod 43, as shown, is provided with but two diameters, however, any number of steps or tapered portions may be added to suit individual fuel control requirements. Actua communication with the mixing conduit at a point below the throttle valve by reason of a tube 41 and consequently is subject to substantially engine intake manifold vacuum. A spring 48 The rotary member 'the diagram, itis to be understood that, the greatest restriction and ,the'zone of highest velocity is formed near the discharge'outlets 22a of the rotary member, themember .22 itself forming part of the restriction. The various members forming this restricted portion may be strearnlined as desired. Power for the operation of motor 26 is supplied by a storage battery 49 through a circuit comprising the 1eads'50, 5|, 52', and'53.

switch device generally indicated at 54. The

. .15 Interposed in this circuit is'a'vacuum responsive f switch device comprises a spring 54a which nor-- mally holds the switch in a circuit closing po-. sition. The switch device is arranged to respond to open-at a :predeterminedintake manifold vacuum. Aresistor 55 connected across switch 54 I is provided and-calibratedtopermit the comparatively-low speed operation of motor 26, even though switch 54 is open. A manual control switch 56 is also interposed in this circuit. The switch56 may be vthe usual automotive ignition In operation when it is desired to start the engine, switch 55 is closedand the switch:.54 will also .be closed, there being no suction in the mixing conduit at this time ,to -open this switch. Under these conditions the rotary member'22 will be rotated atcomparatively high speed by means of motor 26.; This action-willcause fuel to be drawn into the'chamlber 28 and thrown there"- from by centrifugalforce'through passages 22 and transversely into,;the mixing conduit in the general direction of theopenend of annular recess I 9. A reductionjn pressure in chamber 28 will result during high speed rotation of member 22 dueato the flow through passages 22a which, in turn. is. due-to centrifugal force. This reduction in pressure will have the effect of draw-- ing fuel from nozzle 18. The upwardly extending walls of chamber 28 beingtapered outwardly will assist ii -raising fuel moving along their surfaces to thelevel of passagesZZa. The similarly tapered lower outer walls of member 22 will likewise carry fuel upwardfrom'basinl'l to :theair stream through thespace 24. As the engine is cranked, the air ilow through the carburetor will pick up the more finely atomized fuel discharged from passages 22aand also further assist in raising fuel to the level of passage 22a. The amount of fuel available to nozzle l8 under cold starting conditions may be increased by thermostatically control valve means, or the suction in the mixin conduit may be increased under these conditions by the provislon of a thermostatically-or manually controlled choke. Either of these means of temporarily enriching themixture-are well known.

and understood in the art. a

When the engine begins to run under its ownpower ample suction will exist in the zone of member 22 to drawup suflicient fuel to operate the engine and this fuel-will be thrown out into the air stream during that range of operationin whichthe vacuum in the, mixing conduit pos switch through which ignition devices '.,(not shown) are connected. a

passages 2|] and the cross holes 32 therein. It will be noted that the bore of stationary nozzle I8 is so much greater than the size of the cross holes 32 that the flow of fuel or air through these openings will not prevent the drawing of fuel through the main jet l4. It will also be understood that the suction-in the Zone of the top of annular recess l9 will partially balance the suction on nozzle l8 so that the amount of fuel or air entering this nozzle through openings 32 will be somewhat retarded. This flow, however, will be aided by gravity in case, during operation, the level of fuel starts to build up in annulus l9. At normal and high air velocities fuel which drains into basin l1 will be drawn over the upper edge thereof.

In thepresent arrangement, the vacuum control switch, 54 provides two operative speeds for the motor 26 and it is the intention to calibrate switch 54 in such manner that the higher rotative speeds of motor. 26 and, consequently,, impeller 25 and nozzle 22 will occur during operation when the vacuum in the mixture passage below the throttle is comparatively low, a condition which would be attended by comparatively low velocity through the carburetor. {Low velocitiesthrough the mixture conduit will also occur, however, during idling with thefthrottle valve, substantiallyv closedat a time when they vacuum posterior :to the throttleis comparatively high, but under these conditions, fuelissuppliedl'through' the idling systerior to the throttle is insumcient to open the circuit at-switch 54. Any fuel which is not sufficiently atomized to be picked up by the air stream will be received in the annular reces I9 from. which it will drain back to nozzle l lithrough tem, beingqdischarged atv portv 40 and, consequently, thereiwouldnbeeno object inrotating nozzle 22 and impellery25 athigh speeds. By the insertion -of the resistor 55 the motor and driven parts, maybe kept'in motion at all times during; engine operation thereby reducing lag due toinertiaand rendering the device more responsive. It will betunderstood that any suitable. device capable of gradually varying the speed of motor 25 in response to gradualvariations in intake manifold vacuum may be used or, the motor may be cutuout entirely at the higher speeds. At high-engine speeds, however, with the throttle substantially open, the flow through theair inlet will act upon the turbine '25 to greatly increase the.- speed of 'rotation of member 22, thus insuring high atomization of the fuel. Under conditions of high air stream velocity and consequent reduced pressure in'the conduit. theswitch 54 willbe opened and the centrifuge will be driven'by the turbine 25 acted upon by the incoming'air. This arrangement obviously permits the conservation of electrical energy and provides a speed control of the centrifuge proportionate toxthe ,air 'streamvelocity at these higher speeds. An additional pressure upon thefuel in passages 32 and33 is exerted by the spring pressed diaphragm when the I manifoldvacuum suddenly drops as in acceleratlon. l i

The foregoing description and accompanying drawing areintended to be illustrative not limiting and the use of allmodifications of the inventionrwithin the scope ofthe following claims l is contemplated:

- I. claim: 2

l. Inv afcarburetor having a mixture passageflow therethrough, a control circuit for said centrifuge comprising a switch device responsive to vacuum in said mixture passageway posterior to said throttle for varying the speed of said centrifuge.

2. In a carburetor, a mixture passageway, a constant level fuel chamber, a centrifuge device in said mixture passageway adapted to discharge fuel into said mixture passageway transversely to the direction of flow therethrough, a source of power for drivin said centrifuge, a fuel passage leading from said fuel chamber to .said centrifuge, a suction operated fuel metering device capable of restricting the flow of fuel through said fuel passage as the suction in said mixture passageway is increased and a suction operated control device capable of reducing the speed of said centrifuge as the suction in said mixture passageway is increased.

3. In a carburetor having a mixture passageway, a constant level fuel chamber, a, centrifuge device adapted to discharge fuel intosaid m xture passageway. a fuel passageway leading from said fuel chamber to said centrifuge device, and aspring opposed suction responsive device &- pable of discharging fuel under pressure into said centrifuge device when the suction in said mixture conduit is suddenly reduced.

4. In a carburetor, a mixture conduit, a throttle valve in said conduit, a centrifuge device adapted to discharge fuel into said passageway anterior to said throttle valve, a fuel passage leading to said mixture conduit and discharging therein posterior to said throttle valve, 2. source of power for driving said centrifuge, and a suction operated control device responsive to an increase in suction in said conduit posterior to said throttle valve for reducing the speed of said centrifuge.

5. In a carburetor, a mixture conduit, an air inlet to said conduit, a centrifuge device in said conduit adapted to discharge fuel thereinto, a

turbine in said air inlet arranged to drive said centrifuge when the air flow through said inlet is sufficient, an electric motor for supplementing said turbine when the flow through said inlet is insufiicient to drive the centrifuge at the desired speed, a source of electrical energy for driving said motor, and a pressure responsive control device responsive to decreasing pressures in said conduit to reduce the electrical current ,to said motor.

pressure condition in said mixture passageway for controlling said last mentioned drivin means. c

'7. In a carburetor, a mixture passageway, an air inlet leading to said passageway, a fuel chamber, a centrifuge device receiving fuel from said chamber and arranged to discharge fuel into said passageway, means operated by the energy of the air passing through said air inle and independent additional means for driving said centrifuge, and means responsive to the pressure condition in said mixture passageway for controlling one of said driving means.

8. In a carburetor, a fuel chamber, a vertical mixture passageway, a concentric air inlet leading to said mixture passageway, a concentric shaft extending from a point exterior of said carburetor through said air inlet and into said'mixture passageway, an electric motor having its armature carried at the exterior end of said shaft for driving said shaft, a centrifuge device carried on said shaft and in said mixture conduit, said centrifuge being constructed and arranged to discharge fuel into said mixture passagewam'means for conducting fuel from said fuel chamber to said centrifuge, and a turbine carried by said shaft and in said air inlet and arranged to be driven by the flow therethrough.

GEORGE R. ERICSON.

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