US1351624A - Carbureter - Google Patents

Description

A. Cox. v CARBURETER.-

APPLICATION FILED MAR. 1. I919.

i Patented Aug. 31,1920.

3 SHEETS-SHEET L.

A. COX.

CARBURETER. APPUCATION FILED MAR. 1. 1919.

Patented Aug. 31, 1920.

3 SHEETS-SHEET 2.

A. COX.

CARBU.RETER-.

APPLICATION FILED MAR. 1. 1919.

Patentd Aug. 31, 1920."

UNITED STATES PATENT OFFICE,

ARTHUR cox, or omon, NEAR BIRMINGHAM, ENGLAND.

CARB'URETERR Specification of Letters Patent.

Patented Aug. 31, 1920.

Application filed March 1, 1919. Serial No. 280,127.

To all whom it may concern:

"England, have invented certain new and useful Improvements in Carbureters, of which the following is a specification.

My invention has relation to carbureters for internal-combustion engines and consists in an improved single-jet carbureter wherein the production of a correctly-proportioned combustible mixture at all engine speeds and under varying loads and running conditions is realized by regulating the fuelsupply during the opening and closing of the throttle by an arrangement which controls the depression produced by engine suction in the region of the jet or fuel-orifice.

According to the principal and essential feature of my said invention, the jet or fuel orifice is located within or discharges into a primary air branch or inductor tube which is open'at one end to the atmosphere while its other end leads into the main-air passage or mixing chamber of the instrument.

Between the said-jet and the main passage,

there is arranged an air-valve or adjustable air-inlet device which preferably is operated from or in unison with the main throttle valve, and functions by regulating an ad-' mission of air into the branch-tube on the engine side of the jet, .to control or govern the depression which can be produced by engine suction over or in the region of the fuel orifice.

This method of and means for controlling the" fuel supply is applicable to various types of carbureter in which a throttle-valve arrangement is used for regulating the admission of explosive mixture to the engine, but

I will first describe, by way of example, the

application of my invention to a single-jet carbureter in which one lever controls the branch and main air supplies and which embodies a rotary-plug type of throttlevalve.

. Figure 1 of, the drawings represents a sectional view of such a carbureter embodying Figs. 3 and 4 are sections on the lines as and 00 Fig. 1.

Fig. 5 is an elevation of the throttle-operated member of the fuel-controlling device.

Figs. 6 and 7 are longitudinal and transverse sectional views, respectively, of a modification.

In this construction, a is the carbureter livery ends are, by the rotary movement of the throttle, made to register more or less with the intake and outlet a a so as to positively control both the admission of the main air supply into the carbureter and the delivery of the mixture to the engine.

The venturied main passage functions as a controlling choke-tube and also constitutes a portion of the mixing chamber of the carbureter, and the areas of the intake and discharge ends of the same are so proportioned in relation to one another that, at all intermediate settings of the throttle between the full-closed and full-open, engine suction produces within the said mixingchamber a negative pressure of such a value as will maintain an effective suction on the fuel-supply.

' A branch passage or inductor tube 0 leads to the choke b' of the Venturi passage 5, and is located coaxial with the rotational axis of the plug 6. This inductor tube 0- ferred to as the primary-air branch) is internally of a Venturi formation and has a choke at c of a considerably smaller area than the choke in the main passage 1), and it is fitted with a fuel-supply nozzle 03 (hereinafter called the jet) whose orifice 03 leads intothe said choke so that fuel is discharged from the jet into the said branch in a direction at right angles to the primary air stream admitted at the intake 0 The fuel is subjected to the action of the said air at the point, e. the Venturi chokt 0 where the latter attains its maxi mum velocity, with the result-that the primary air is utilized to the best advantage for primarily atomizing the fuel and produces within the branch 0, a primary mixture that is discharged laterally into the chamber 6 and there mixed with the mainair supply admitted at the intake a. The jet orifice d may be regulated by means of a suitable needle valve 9.

The air-admission valve which controls the fuel supply is arranged on the engine side of the jet, 6. 0. between the choke c and the outlet 0 of the branch 0 into the passage 6 It consists of a system of air ports 0 in the tube and an angularly-displaceable sleeve a mounted on the ported part of the said tube and formed with a series of openings e corresponding in number to the ports 0 the said valve-sleeve 6 being directly connected to the throttle member I) by a slot and set-pin e e, in such a way that, while the sleeve is capable of angular adjustment upon or relative to the throttle within the limits imposed by the length of theslot 0 the two members I) and e are normally locked together by the set-pin e and are rotated as one unit by the throttle-control mechanism.

The valve-sleeve e is adapted to be set with its openings e in such relationship to the air-ports e that movement of the throttle in the opening-up direction will reduce the effective area of air-passagethrough the openings 0 e, and restrict the admission of air into the said branch, whereas throttle movement in the contrary (closing down) direction will enlarge the effective air-passage area at 6 e and admit an increasing amount of air as the throttle approaches the full-closed position, with the result that engine suction isenabled to produce and maintain a relatively greater fuel-inducing depression above the et at larger throttle openings (when the inlets of the valve are closed or only slightly open) than can be produced by the action of engine suction at small throttle openingswhen the said valve admits air more freely into the branch on the engine side of the jet. In other words, the valve 6, e e ,'is adapted to directly control the depression and air stream velocity at the jet in synchronism with the opening and closing of the throttle,.or in such a way that the jet will be caused to deliver the correct amount of fuel for forming the total air admitted by way of the primary and main air intakes, a correctly-proportioned combustible mixture.

Thefuel-discharging area of the jet orifice is normally a constant or non-varying factor, inasmuch as the said area is not changed or altered by or during the movement of the main throttle,- and the said orifice is of such a size as will pass all the fuel required to produce the maximum quantity of mixture for satisfying the demands of the engine when the throttle is full 0 en at other positions of the throttle in w llCll it functions as a factor for controlling engine speed, the action of the valve cuts down the primary air fiow across the jet and so brings the jet under a reduced fuel-inducing depression.

The fact that the primary air then draws upon a relatively large fuel orifice enables the said air to take up sufficient fuel to produce (with the main air) the quantity of correctly proportioned mixture required for The openings in the valve sleeve and primary air branch may be made of any desired shape or size depending on the results required. For instance, they ma be made with V-like extensions 6 as in t e example shown in the drawing; these extensions being so arranged that during the opening ofthe throttle, they may be utilized to maintain communication between the atmos here and the inductor tube a after the thrott e has been turned through an arc of movement exceeding the diameter of the air ports in the sleeve, whereby a certain amount of air'can be admitted at the valve even when the throttle is fully open.

In a carbureter as above described, when the throttle is opened beyond the starting position, the resulting acceleration of the 'en gine exerts an increased suction in the dis-. charge end of the primary air branch; but the fact that air can then be freely drawn through the valve 6 e so modifies this suction as to induce a fuel flow suflicient only to correctly carburet the air that is then being taken into the carbureter. i Continued opening of the throttle provides for, further engine acceleration, but simultaneously restricts the air admitted through the sleeve valve which enables engine-suction to maintain the relatively greater depression over the jet for inducing a fuel-flow sufiicient to form a correct mix- -ture with the increasing'quantityof air that is being drawn through the main air passage, and as the opening up of the throttle proceeds, so the sleeve valve may continue to out down the air and augment the depression above the jet until, at the maximum throttle opening, only the extreme V-ends of the sleeve openings are or may be in register with the branch-tube ports, and the value 126 of' the fuel-inducing depression above the jet is then governed only by engine revolutions'except when modified by such small quantity of air as can enter the existing port openings of the valve. i

But, by adopting ports of suitable shapes, or byappropriately adjusting the relative positions'of the sleeves and throttle when regulating the carbureter, provision may be madeifor entirely closing the valve air-intakes' when or before the throttle is at its maximum opening. In fact, the system admits of the depression above the jet being controlled over the whole or any desired part of the range of throttle 'movem'ent,and of the control being timed so that it will come into operation early or late in such throttle movement, according to the car bureting results required. I

Furthermore, the facts that both the primary and main airpa'ssa'ges are venturied, and that the primary. passage discharges into the main venturi intermediate the main.

air and mixture-controlling elements of the throttle valve enables the velocity of the main air'stream to maintain on the primaryair and fuel supplies, a suction whose value depends upon the volume of main air whichv the engine is drawing'through the throttle venturi atany given speed. And as the jet orifice in the primary air passage is removed from the direct influence of engine suction,-

it is impossible (so long as the fuel-orifice area has been appropriately adjusted to give the correct fuel value to the mixture all along the scale) for the carbureter to produce an over-rich mixture, even at the highest engine speeds, since the supply of fuel undersuch conditions depends upon the depression that is maintained at the discharge end of the primary branch by the actual volume of main air that has to be carbureted.

The invention herein described may also be applied, as shown in F ig s. 6 and 7, to a carbureter wherein two linked butterfly valves h, h are used; these valves being I disposed respectively on the atmospheric and engine sides of the discharge end of the primary branch, so that the space between them constitutes the main mixing chamber.

The linkage '11 coupling the two valves to their control mechanism is also connected,

such as by the arrangement shown in the said figures, to the movable member of the atmospheric valve.

In a carbureter embodying a 'maincontrol or throttle. valve other than' of the rotary plug type, the primary air branch may lead into the main mixing chamber or main-air passage atlany convenient point and in any convement direction.

Having now described my invention,

or induction tube having an air intake; a fuel supplyjet located in' said branch; a mam air passage into which the primary 'air branch leads; and an adjustable, valve remote from said air intake adapted to adengines, comprising a primary. air branch mit air into said branch at the engine side of the jet for controlling thefuel supply.

2. 'A carbureter for" internal combustion engines, comprising a primary air branch or inductiontube having an air intake; a fuel supply jet located in said branch; a

main a1r passage; an adjustable air-admission valve located in said branch remote from said air intake; and a throttle valve located in said main air passage and connected for simultaneous operation with the air-admission valve so that the latter re- :stricts the admission of air therethrough during opening movement of the throttle valve, and vice versa.

-3. A single et carbureter, comprlsmg a I main air passage; a throttle therein em bodying two main elements respectively controlling the admission of main air into the air passage andthe delivery of mixture to the engine; a primary air induction branch open at one end to the atmosphere and leading at its other end into the main air passage intermediate the two throttle elements; a fuel jet discharging into the primary air branch; and an adjustableair admission valve located in said branch between the delivery end thereof and the fuel jet and connected for operation with the throttle elements.

' 4:. A carburetervfor internal combustion engines, comprising a primary air branch or induction tube; a fuel supply jet located therein; a main air passage into which the primary air branch leads; an adjustable air-admission valve located in said branch intermediatethe fuel jet and the main air passage and embodying fixed and'movable v members having cooperating series of ports;

crating movement with the throttlevalve.

Signed at Birmingham, England, this 28th day of'January A. D. '1919.

- ARTHUR COX.

'fixed member and independently of its opv

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