US2403390A - Charge forming device - Google Patents

Description

July 4 J. T. w. MOSELEY ETAL 2,403,390

CHARGE FORMING DEVICE Filed Nov. 1, 1945 F I G. 2.

INVENTORS JAMES- T.W. MOSELEY HAROLD A. CARLSON Y ALEX. N. SZWARGULSKI ATTORNEY Patented July 2, 1946 2,403,390 CHARGE FORMING DEVICE James T. W. Moseley, Clayton, Harold A. Carlson,

Univers ity City, and Alex N. Szwargulski,

St. Louis, Mo., assignors to Carter Carburetor v Corporation, St. Louis, Mo., a corporation of Delaware Application November 1, 1943, Serial No. 508,572

r 3 Claims.

1 This invention relates to charge iorming devices for internal combustion engines and consists particularly in means for supplying an additional fue1 charge to the engine under certain conditions together with means to incapacitate the same under other conditions. 7

Where an automotive engine carburetor is provided with a throttle operated accelerating pump, it is frequently undesirable to have the pump discharge into the mixture conduit when the sue tion therein exceeds a certain value, irrespective of throttle movements. There have been devices for preventing the pump discharge under certain conditions, but so far as present inventors are aware, there has been no device which is efiec=- tively responsive to engine suction alone to prevent the pump discharge.

Accordingly, the object of the present invention is to provide a carburetor accelerating pump structure including means for definitely preventing the pumpdischarge under high suction conditions, irrespective of throttle movements.

This object and other more detailed objects hereafter. appearing are attained substantially by the structure illustrated in the accompanying drawing, in which Fig. 1 is a vertical section through a carburetor, somewhat diagrammatically arranged, and illus... trating one form or the invention.

Fig. 2 is a similar view of a carburetor embodying a modification.

Fig. 3 is a detail view showing another modification. I

In eachioi the forms shown, the carburetor comprises a downdraft mixture barrel including an air inlet portion 5, mixing chamber 6, a series of venturis l, an outlet portion 8, flanged as at Q for attachment to the usual engine intake manifold (not shown). A butterfly-type throttle valve to controls the discharge oi combustible mixture from the carburetor. Adjacent the barrel there is provided a bowl ii in-which fuel is maintained at a substantially constant level by float i2 and needle valve mechanism (not'shown) "lhe main fuel supply pwses through a metering orifice element id and upwardly inclined main fuel passage it counicating by means of nozzledt with the smallest venturi '2. Fuel for idling is supplied through passage ll, extending up- .wardly from inclined passage 15, and a downwardly extending passage l8 terminating in idling port l9 adjacent the edge. of the throttle plate when closed. Metering orifice I4 is controlled by a metering pin 20 operated Irom the throttle by 55 2 a a centrally pivoted lever 2i and a link 22 connected to arm 23 rigid with the throttle shaft.

An accelerating pump is also provided in the bowl including cylinder 25 and piston as operated 5- from the throttle by a, split lever 2'! and link 28 connected to arm as rigid with the throttle shaft.

The parts oi split lever 27 are yieldingly maintained in alignmentby a coiled spring so so that the pressure which can be exerted upon piston lo 2t is limited by the strength of this spring.

Upon closing movement of the throttle, fuel is drawn into cylinder 25 through a passage 32 past inlet check 33. Upon opening movements of the throttle, fuel is forced by the piston into the is mixture conduit.

In Fig. l, the pump is discharged through outlet passage 36 and against a non-cylindrical needle element 85 resting in the upper part oi outlet passage 342. an enlarged chamber tit -con= go nects passage 8 3 with a downward passage 3? which-opens into the mixture conduit posterior to I throttle to. A check ball in chamberdd normally seats against the upper edge of passage ti and also rests against or just clears needle eleao ment 35. The arrangement of. element 35 and hail check as is such that upon discharge of the pump, element 355 is raised by the pump pressure against the ball so as to tend to unseat the latter and permit the passage of pumped fuel into the 89 mixture conduit. However, when the engine sue tlon applied to the relatively large exposed face of ball 38 is above a predetermined degree, say 8" of mercury, the pump cannot produce suficient pressure to lift the ball, because of yielding oper- 3s ative connection 2?, 3d and, thereafter, the spring W is stretched and no fuel is pumped.

In Fig. 2, the pump discharge passage it is provided with a control valve 35 in the form of a goose neck stem which extends upwardly through so a passage 32 intersecting discharge passage dd.

Adjacent passage d2 is an enlarged chamber 63 in which there is slidably received a piston l l constantly urged upwardly by a coiled compression spring 35, so as to normally urge valve ll 5 clear of its seat at the upper edge oi pump dis charge passage d6. Chamber #33 communicates with the mixture conduit posterior to the throttle by means of a suction passage ll. The arrangement is such that engine suction applied to the relatively large exposed surface of piston dd tends to hold valve 5| against its seat, and when this ,suction exceeds a predetermined value, as in the first form, the maximum pump pressure, when applied to valve M, is insumcient to unseat the same and the discharge of accelerating fuel is 'used, preferably,

' sure from said pump,

said passageway,

to the pump cylinder when valve 4| is held closed. The by-pass, however, may be omitted where the pump operating mechanismis yieldable, as shown. Any suitable type of accelerating pump may be provided with a yieldable pressure relief. Since an opening movement of the carburetor throttle is inevitably accompanied by a drop in suction in the mixture conduit'posterior to the throttle, the pump may be operated by this suction as shown in Fig. 3. In this form, the pump piston 26a. is rigidly connected to a suction piston 50, both being normally urged downwardly in cylinder 25a by a compression spring 5|. A passage 52 connects suction chamber 53 to the mixture conduit posterior .to the throttle. When a drop in intake suction occurs, spring 5| urges the piston downwardly to force fuel through outlet passage 34a, provided the control valve arrangement, as at 35, 38 in Fig. 1, permits. When the suction again increases, the pistons arelifted against spring 5|. An air vent is shown at 52. Operation of the pump piston coincides with movements of the throttle, as in Figs. 1 and 2. The structure may be modified in other respects as will occur to those skilled in the art. The exclusive use of all modifications as some within the scope of the appended claims is contemplated.

We claim: 1. In a charge forming device, a mixture conduit having a throttle therein, an accelerating pump, yieldable means to discharge said pump responsive to opening said throttle, a passageway between said accelerating pump discharge and said mixing conduit, a pair of oppositely facing valve seats formed in said passageway; a pressure actuated valve for one of said seats normally closing said passageway and unseated by fluid presa suction responsive valve arranged for seating engagement with the opposite valve seat, said suction actuated valve being seated responsive to relativelyhigh suction conditions in said mixture conduit for closing and means for unseating said suction actuated valve upon operation of said pressure responsive valve.

4 2. In a. charge forming device, a mixture conduit having a throttle therein, an accelerating pump, yieldable means to discharge said pump responsive to opening of said throttle, a passageway between said accelerating pump discharge and said mixing conduit, a pair of oppositely i'acing valve seats formed in said passageway, a pressure actuated valve for one of said seats normally closing said passageway and unseated by fluid pressure from said pump, a suction actuated valve arranged for seating engagement with the opposite valve seat, said suction actuated valve being seated responsive to relatively high suction conditions in said mixing conduit for closing said passageway and for applying pressure to said pressure actuated valve to assist in retaining said pressure actuated valve On its seat, and means for unseating said suction actuated valve under I normal or low suction conditions upon operation passageways of said pressure actuated valve.

3. In a charge forming device, a mixing conduit having a throttle therein, an accelerating pump, yielding means to discharge said pump responsive to opening of said throttle, intersecting passageways forming a. connection between said pump discharge and said mixing conduit, a pair of oppositely facing valve seats formed in said intersecting passageways, one of said seats being located in the first of said passageways, the other seat being located at the intersection of said passageways, a pressure actuated valve for the first of said seats normally closing the first of said and unseated by fluid pressure from said pump, a suction actuated valve arranged for seating with the, opposite valve seat, said suction actuated valve being seated responsive to relatively high suction conditions in said mixing conduit for closing the second of said passageways and for applying pressure to said pressure actuated valve to assist in retaining said pressure actuated valve on its seat, and means for unseating said suction actuated valve under normal or low suction conditions upon operation of said pressure actuated valve.

. JAli/IES 'r. w. mosnnar.

HAROLD a. crimson. ALEX N. SZWARGULSKI.

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