US2315183A

US2315183A - Dual carburetor

Info

Publication number: US2315183A
Application number: US366262A
Authority: US
Inventors: George M Bicknell; Van C Worden
Original assignee: Carter Carburetor Corp
Current assignee: Carter Carburetor Corp
Priority date: 1940-11-19
Filing date: 1940-11-19
Publication date: 1943-03-30
Anticipated expiration: 1960-03-30

Description

March 1943. G. M. BICKNELL ETAL 3 I DUAL CARBURETOR Filed Nov. 1a, 1940 I a My 94/ I l5 i. Q

INVENTORS GEORGE M.BICKNELL VAN C.WORDEN ATTORNEY Patented Mar. 30, 1943 DUAL CARBURETOR George M. Bicknell, St. Louis, Mo., and Van C.

Worden, Detroit, Miclm assignors to Carter Carburetor Corporation, St.

poration of Delaware Application November 19, 1940, Serial No.366,262

1 Claim. (Cl. 261-41) I This invention relates to carburetors for. internal combustion engines and consists particularly in novel throttling devices for controlling the fuel and fuel mixture passages of a multiple barrel carburetor.

In the usual form of automotive carburetors now in use, liquid fuel is discharged into a venturi located anterior to the throttle valve where the suction available for drawing fuel from the nozzle is substantially directly proportional to the degree of opening of the throttle valve and the engine speed. It is desirable that the main fuel nozzle discharge into a restricted zone, preferably of Venturi shape, so that under the least favorable suction conditions, that is, when the throttle is substantially closed or when the throttle is more fully opened but the engine is operating slowly, quantities of fuel are discharged from the main nozzle. Accordingly, the size of the mixture conduit is necessarily a compromise between the relatively small size which is an ad,- vantage at low speeds, and the larger size which has maximum capacity for high speed operation.

In order to overcome the disadvantages of this compromise, which results in decreased fuel discharge at, low speeds and also decreased capacity at high speeds, separate carburetors may be provided, in one of which, the mixture controlling valve or throttle may be manually operated, in the usual manner, and in the other of which the mixture controlling valve is at least partly controlled according to suction conditions in the first carburetor anterior to the throttle or throttle position, so that the second carburetor functions, substantially, only at the higher speeds and serves, in effect, to increase the capacity of the carbureting. system, without reducing the effective fuel discharge at the lower speeds.' For convenience, it is desirable to form the two carburetors, into a single body structure in which the multiple mixture conduit has a common air inlet upon which the air cleaner and silencer device is mounted. The linkage connections for controlling the throttle valves, one manually and the other according to suction conditions, are greatly simplified over the case where wholly separate carburetors are used, but since suction may be transmitted from one mixture conduit or barrel to the other through the common air inlet, it is necessary that the main fuel nozzle of the suction controlled conduit or barrel be cut off at all times when this barrel is supposedly out of operation. It is desirable, however, to provide an idlingsystem in each barrel or mixture conduit, and for this reason, the idling system in (not shown).

Louis, Mo., a corthe suction controlled barrel, must obtainits fuel independently of the main nozzle discharging into this barrel.

An object of the present invention is, therefore,

to provide a carburetor having multiple fuelmix-- ture conduits with a common air inlet, in which means is provided to prevent discharge from the fuel nozzle supplying one of the conduits, except under conditions when this nozzle is caused to discharge by the suction condition in the barrel with which it is associated;

Another objectis to provide a novel, multiple barrel carburetor in which each barrel is vprovided with its own idling system adapted to function whenever the throttle therein is substantially closed, while, at the same time, providing for cutting ofi of the main nozzle in the secondary or suction operated barrel.

These objects and other more detailed objects hereafter appearing are attained substantially by the structure illustrated in the accompanying drawing in which the figure is a cross sectional diagrammatic view of a carburetor embodying the invention.

The carburetor shown is of the downdraft type having a divided mixture conduit, the lower portion thereof forming a pair of mixing conduits l and 2 including venturis 3 and l and havin a common air inlet horn 5. Butterfly throttle valves 6 and l are mounted, respectively, in the lower or discharge portions of the mixture conduits and a choke valve 8 is similarly mounted in air horn 5. The choke valve may be operated by any suitable manual or automaticcontrol device The air horn is provided with an annular rib 9 to facilitate the mounting of the usual air cleaner and silencer device (not shown).

Throttle valve 6 has an arm l2 rigidly secured to its shaft i3 and to this arm there is connected a link I4 extending to the usual throttle pedal for manual control of the valve. Throttle ,I has a lever l5 rigid with its shaft l6 and to the outer end of this lever is pinned a rod H which is secured to the lower, movable end i8 of a bellows l 9. The bellows is supported at its upper end by a bracket 20, secured to the body of the carburetor, and an apertured lug 2i slidably receives and guides throttle operating rod ll. A tube 22 extends. to a port 23 opening into mixture conduit i controlled by manual throttle 6 so that the suction conditions in this conduit are transmitted tobellows IS. The bellows is preferably of the self-expanding or resilient type so as to normally maintain suction controlled throttle I in its closed posit-ion, as shown, the

resilience of the bellows and the linkage being shown at 21. A main fuel passage or nozzle 26 communicates with the fuel reservoir through a calibrated metering orifice 29 and discharges into the smallest or primary venturi 3 in mixture conduit I. A second main nozzle 30 communicates with the fuel reservoir through a calibrated metering restriction 3| and communicates with the smallest or primary venturi 4 in second mixture conduit 2. Metering orifice or restriction 28 is controlled by a. -metering rod. 32 pinned at its upper end to a lever 33 which is pivotally mounted at 34 and connected at its opposite end by means of a link 35 to an arm '36 rigid with manual throttle shaft 13. Metering pin 32 and its control linkage are arranged so that as manual throttle 6 is opened, the metering pin will be raised so as to progressively move smaller portions thereof into metering orifice i9 and thus enrich the mixture being discharged through mixture conduit I.

The second metering orifice 3| is controlled by a metering pin 40 yieldingly connected at its upper endto a pivoted lever 4|, this lever being connected-at its end opposite pin 40 by means of a link 43 to an arm 44 rigid with suction controlled throttle shaft l6. Metering pin 40 has an enlargement 45 positioned to seat against the upper edge of orifice 3| and cut off the communication between secondary and main nozzle 30 and the constant level fuel reservoir wheneve throttle 1 is substantially closed.

shot of fuel in the mixture conduit I when throttle 6 is opened. Any suitable type of accelerating pump and valving may be provided.

In operation, the carbureting elements shown at the left side of the figure, including mixture conduit I. main nozzle 26, idling system 48, Ill,

metering pin 32, and accelerating pump 64 function to. provide properly metered fuel for all low speed operating conditions. The elements shown at the right side of the figure, including mixture conduit 2, idling system 43, 5|, metering pin 40, and main nozzle provide a secondary carburetor in which the idling system discharges substantially continuously whenever port 49 is exposed to suction, but in which no fuel can be drawn from main nozzle 30 until the suction in mixture conduit I is sumcient to indicate a predetermined speed, say miles an hour, at which the added fuel is desired, whereupon bellows I! will be contracted, opening throttle I and also valve enlargement controlling metering orifice 3|.

There is thus formed in a compact, unitary carburetor, structure for insuring the most eillcient discharge of fuel under low speed conditions while. at the same time, providing for greatly increased capacity under high speed conditions.

various features are conventional and these and When'throttle valves 6 and l are substantially closed, fuel is supplied to mixture conduits l and 2 through the usual idling ports 48 and 49 communicating with the constant level reservoir through passages 50 and 5| having restrictions 52 and 53 and air bleeds 54 and 55. Idling passage 50 supplying mixture conduit I communicates with the enlarged lower portion 56 of main fuel passage 28 posterior to metering restriction 29 so as to form an interconnected idle in which all fuel for supplying both the main and idling passages flows through a single metering restriction. Idlingpassage 5| supplying the secondary mixture conduit 2, communicates with the fuel reservoir by means of a port 58 which is indei pendent of main nozzle 30 so that fuel will be.

discharged from idling port 49 whenever throttle I is substantially closed, regardless of the position of metering pin 40.

A third arm 60 is formed rigidly on manual throttle shaft l3 and connected by a link 6| to .a lever pivotally-mounted at 63, the lever being connected at its other end to a piston rod 64 and piston 65 forming an accelerating pump. Piston 65 operates in cylinder 66 so as to discharge a others may be modified in such respects as will occur to those skilled in the art without departing from the spirit of the invention. The exclusive use of all such modifications as come within the scope of the appended claim is contemplated.

We claim:

In a dual carburetor, a fuel reservoir, first and second induction conduits having a common air inlet pipe and each having a venturi, main fuel nozzles for supplying fuel from said reservoir to each of said induction conduits, throttle valves for each conduit, idling systems for each of said conduits, the idling system for the first conduit communicating with the fuel nozzle-for said conduit and the idling system for the second conduit communicating with, the fuel reservoir independent of the second fuel nozzle, a metering pin controlling each main fuel nozzle, the metering pin for the fuel nozzle supplying the first induction tube being constructed and arranged to control the fuel flow to the idling system when the throttle valve for the first induction conduit is in closed position and the metering pin. controlling the main fuel nozzle to the second induction conduit including a valve constructed and arranged to close the fuel supply to said nozzle when the throttle valve for the second conduit is in closed position, manual means for operating the throttle valve and metering pin regulating the fuel supply to the first conduit, and means controlled by the pressure in the first conduit anterior to its throttle for operating the throttle valve and metering pin controlling the supply of fuel to the second conduit.

GEORGE M. BICKNELL. ..VAN C. WORDEN.