US2329748A - Carburetor metering control - Google Patents

Description

Sept. 21, 1943. L, DELEN 4 CARBURETOR METERING CONTROL Filed March 14, 1941 FIG.5.

FIG.2.

|NVENTOR JAMES L. EDELEN W u ATTORNFY Flea,

Patented Sept. 21, 1943 2,329,748 g c RBURE'roR METERING CONTROL James L. Edelen, St. .Louis, Mo., assignor to Carter Carburetor Corporation, St. Louis, a corporation of Delaware Application March 14, 1941, Serial No. 383,233.

7 Claims.

This invention relates to carburetors for internal combustion engines of the automotive type and consists particularly in novel mechanism for providing proper metering of the liquid fuel supply adaptable to a universal type of carburetor and adjustable to conform with the requirements of diiferent engines.

In the well known Carter carburetor, the liquid fuel supplied to the main nozzle is metered through a main metering orifice located at the bottom of the carburetor constant level chamber. A stepped or tapered metering pin cooperates with the metering orifice to vary the effective size of the metering orifice and thus control. the richness of the mixture supplied by the carburetor in accordance with the power demand upon the engine. Such a metering arrangement is called an economizer or step-up device. The power demand, in some cases, varies directly with the degree of opening of the carburetor throttle and, accordingly, the economizer may be controlled with the throttle valve by a direct connection thereto. In other cases, it is desirable to provide for variation of the position of the economizer in accordance with suction in the engine intake manifold and more or less independently of the throttle position. For instance, the Chevrolet engine operates very satisfactorily with a carburetor having a so-called manual metering pin, that is, a metering pin which is directly connected to the throttle. On the other hand, the Plymouth engine operates better with a carburetor having a metering pin or needle controlled by suction. Obviously, a carburetor, to operate most satisfactorily with a particular engine, should have either a manual ora suction controlled economizer as determined by the characteristics of the particular engine.

The use of the carburetor with a governor of the flow restricting type alters the metering requirements, particularly in that the economizer should assume a lean position in accordance with the manifold suction as soon asv the engine reaches the governed speed, but irrespective of the throttle position, since the drivers of governed vehicles usually hold the throttle valve farther open than is necessary and rely on the governor to limit the speed. I

In the Carter carburetor, the metering pin is controlled through the intermediary cf the accelerating pump leverage mounted on the fuel bowl cover. .The pump piston is operated by a con.- nection to the throttlevalve, but frequently, a yielding throttle connection is provided, conveniently by means of a split or two-part leverage, the parts of which are resiliently held in their normal functioning position. The present invention contemplates the use of a spring connected to one ofthe pump leverageparts and which may be attached to the metering pin mechanism to affect the suction control thereof. Obviously, this spring affects the effective resilience of the pump operating connection.

Accordingly, it is an object of the present in-.

vention to provide an automobile carburetor having simply adjustable'means to accommodate the carburetor to varied engine and governor requirements, as mentioned above. I A more specific object is toprovide a carburetor in which the metering device may be readilyconverted from a full manual control to partial manual partiai suction control or to full suction control.

Still another object is to provide spring means functioning in association with the metering mechanism and the pump leverage for selectively rendering the suction control of the metering mechanism inoperative, partially operative, or fully operative without, at the same time, substantially affecting the resilienceof the pumps throttle connection.

These objects and other more detailed objects hereafter appearing are attained substantially by the carburetor structure illustrated in the accom panying drawing in which Fig. 1 is a side view and vertical section showing various parts of the carburetor embodying the invention. i

Fig. 2 is a detail-side view-and section showing a portion of the structure in Fig. 1 but with the manual control of the metering pin eliminated. Fig. 3 Ba view similar to Fig. 2 but showing the partsin a position to attain partial manual and partial suction control of the metering mechanism. 1

Fig. 4 is a detail view showing the pump leverage stressed.

Fig. 5: is a detail section taken on line 55 of fuel is maintained at a constant level by the At one side of the float bowl there is provided" i a cylinder I! which is ported at atmosphere in its upper portion, as at i8 and which, at its, lower portion, is connected by means ofa. passage [3' with the outlet portion of the carburetor mixture conduit posterior to throttle 9. Slidable in cylinder I? is a piston normally urged upwardlyv by a coiled spring 2|. attached to the upper portion of piston 29 by a pin- 26.- A metering. pin; 21 is attached to the upper portion of:r0d- 25 by: means of a; pin 23 and: has a stepped, lower portion, as shown, whichextends. through metering orifice member I3, for controlling the effective size thereof.

Located in; another-portion. of the float bowl is a-seccnd cylinder 29.: in. which, is slidably received a pistontd normally urged: upwardly by a coiled spring 3!. A piston: Od 32 is attached to the piston and; at its upperendisconnected by means-of anoperating link3-3to a lever 34 rotatable on. a shaft 3-5-mountedabc-ve bowl cover 36. A second lever 31 is also rotatably mounted on shaft 35 and extends; oppositel to lever 34, the outer end of lever. 31 being connected by alinkfl to throttle arm- It. Levers 3,4: and 3'! are provided, respectively, with ears 4| and 42 normally maintained in abutting relationship by a spring 43 tensioned between a lug 44 on lever 34? and a lug. Bionlever. 31. Thetwo-part leverage mechanism, connector rod 33;, and. arm M constitute a resilient operating connectionbetween pump piston. 36. and the throttle valve so that when the throttle valve is opened, the pump piston is depressed in. cylinder 29for supplying a pick-up charge of fuel intothemixtureconduit. Spring 3| beneath the pump piston is weaker than ten-.

sion spring. 43 and merely serves to keep slack out. of the pump operating linkage. The pump is provided with the usual intake check 46 in passage 4T communicating with the float bowl, and an. outlet check 41a inv a. passage, partly shown at 48' communicating with any suitable point in the carburetor barrel.

A torsion spring 513. is wound. about pump lever shaft 35 andhasone end 5t hooked over the portion 34' of the pump leverage and has a second, longer arm 52 which, in Fig. 1, is hooked over the top of suction piston rod 25. Pump lever 31 is provided with a transverse slot 53 in which there is adjustably positioned a pin 54. Projecting from suction piston rod 25 above pin; 54 i a finger 55 forming, in efiect, a one-wayoperative connection between the pump leverage and the metering pin control mechanism.

Rod 25 operates in a guiding boss 58 projecting above bowl cover 3.6 and on one side of this projection there is provided a shoulder 51. This shoulder is positioned so as to receive long end 52 of torsion spring when it is disconnected from suction piston rod 25. (Figs. 2 and 3.)

As best shown in Fig. 5, pin 54 is partially threaded and is releasedly attached in position in slot 53 by means. of a nut 68 and lock washer Bl so that the pin may be secured. either above or below finger projecting from piston rod 25 or may be entirely removed so as to free the suction metering mechanism from the influence of the pump leverage.

The operation of the mechanism is as follows:

Torsion spring 50 is stronger than spring 2! tending to elevate suction piston 20 so that when extension Won the torsion spring is hooked over piston rod 25., finger 55 on the piston rod held permanently in engagement with pin 54, as shown in Fig. 1. In this position of the parts, the meterin rod is fully responsive to movement of the throttle and the suction control is eliminated.

' This type of metering control is particularly advantageous with a Chevrolet engine, for instance,

when used without a governor.

An L-shaped rod 25. is,

Fig. 2 shows torsion spring extension 52 hooked over shoulder 51 on piston rod guiding boss 56 so as to substantially continue the effect of this spring upon the resiliency of the pump operating leverage. Pin 54 is removed from slot 53 so that the manual control of the metering pin is eliminated entirely. In this, figure, the metering mechanism, becomes fully automatic or suction controlled in accordance with differential presa restricting position in the metering orifice as soon as the governed speed is reached during acceleration and held in this position thereafter even though the throttle may be fully opened or nearly so. The full suction controlled metering in Fig. 3 satisfies both requirements.

In the third arrangement shown in Fig. 3, pin 54 is located in slot 53 above finger 55 on suction piston rod 25 and torsion spring extension 52 is hooked over shoulder 51 and released from rod 25, as in Fig. 2. This provides for a limitation of the upward movement of metering mechanism under the influence of spring 2|, in' accordance with the position of the pump leverage and throttle valve, while permitting lowering of the metering pin to a restricting or economy position when justified by relatively high intake suction, regardless of the position of the throttle valve. This arrangement is beneficial when used with an engine such as the Chevrolet having a governor applied thereto.

Obviously, the adjustments and modifications above described may be easily made in the field so that a single carburetor ma be made to function satisfactorily for a number of different applications. Thus, a garageman or retail merchant need stock a much maller number of carburetors as a single carburetor may be readily adjusted to function properly with or without governor and with different types of engines. Ordinarily, the mere changing of metering orifices and metering rods is not enough to adapt a carburetor for the varied usages mentioned above, including satis factory performance either in connection with the governor or without one.

Various features may be modified as will ocour to those skilled in the art and th exclusive use of all such modifications as come within the scope of the appended claims: is contemplated.

I claim:

1. In a carburetor, an induction conduit, a throttle therein, a metering pin, means to control said pin responsive to suction conditions in said conduit, a throttle actuated member, and operating elements normally movable with said pin and said member to provide for one way operation of said pin by said throttle, one of said cooperating elements being capable of predetermined selective assembly with relation to the other cooperating element whereby the desired direction of movement of the pin by throttle movement may be obtained.

2. A carburetor as specified in claim 1 further including a device carried by the carburetor and selectively movable to a first position to maintain said cooperating elements constantly in engagement for full throttle control of said metering pin and to a second position to release said elements.

3. In a carburetor, a mixture. conduit, a throttle therein, an accelerating pump, a resilient operative connection between said throttle and said pump, mechanism including a metering pin and a device responsive to suction conditions in said conduit for controlling said pin, cooperating elements on said resilient connection and said pin forming a one-way operative connection between said throttle and said pin, a normally stressed spring applied to one end to said connection and affecting the resiliency thereof, and holding catches on said metering pin mechanism and adjacent the same, the other end of said spring being normally applied to one of said catches and being selectively movable therebetween without substantially varying the effect of said spring upon said connection.

4. In a carburetor, an induction conduit, a throttle therein, an accelerating pump, an operative connection between said throttle and said pump including pivoted levers having cooperating abutments forming a one-way connection therebetween, spring means normally stressed to urge said abutments into engagement, suction controlled metering pin mechanism, cooperating elements on one of said pump levers and said mechanism forming a one-way operative connection therebetween, and catch abutments on said mechanism and adjacent the same, said lever spring means having a projection selectively engageable with one or the other of said catch abutments Without substantially affecting the stressing of said means.

5. A carburetor as specified in claim 4 in which said metering pin mechanism includes yielding means normally urging said mechanism in opposition to the suction effect thereon, said spring projection, when engaged with the catch abutment on said metering pin mechanism affecting the actuation of said mechanism by said yielding means.

6. In a carburetor, an induction conduit, a throttle therein, a member movable with said throttle, a metering pin, operating mechanism for said pin including cooperating elements normally connected respectively with said pin and said member whereby said elements constitute a one-way control for said mechanism, and means responsive to suction changes in said conduit for supplying actuating force to said mechanism during operation of the carburetor, one of said cooperating elements being removable to eliminate the controlling effect of said actuator upon said metering mechanism, and being further capable of selective assembling with respect to the other element to provide a one-way control of said metering pin in either direction.

'7. In a carburetor for an internal combustion engine, a throttle, a fuel metering orifice and metering valve therefor, means responsive to engine suction for operating said valve, a throttle actuated member having a slot, said suction responsive means having an element adjacent said slot, and a valve actuator secured in said slot and forming with said element a one-way operative connection between said throttle actuated member and said valve, said actuator being selectively adjustable in said slot to positions on either side of said actuator for reversing the efiectiveness of said one-way connection.

JAMES-TL. EDELEN.

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