US2762615A - Vacuum control for injection carburetors - Google Patents

Description

pt 1956 o. R. CEDARHOLM VACUUM CONTROL. FOR INJECTION CARBURETORS Filed June 21, 1954 Oscar R. Cedarho/m IN V EN TOR.

United States Patent VACUUM CONTROL FOR INJECTION CARBURETORS Oscar R. Cedarholm, Los Angeles, Calif.

Application June 21, 1954, Serial No. 437,983

2 Claims. (Cl. 261-69) This invention comprises novel and useful improvements in an automatic control for injection carburetors and relates to similar subject matter and constitutes an improvement over my prior Patent No. 2,653,804, issued September 29, 1953.

A primary object of this invention is to provide an improvement in the valve body shifting mechanism of my above identified patent whereby the air fuel ratio may be more accurately adjusted and controlled.

These, together with other objects and advantages which will become subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

' Figure l is a side elevational view of a carburetor constructed in accordance with this invention;

Figure 2 is a vertical section taken through the carburetor shown in Figure 1 showing the same in engine idling position; and

Figure 3 is a transverse vertical section taken substantially along the plane of section line 33 of Figure 2.

Referring now more particularly to the drawings, reference numeral indicates the carburetor body generally which includes an upper portion 12 having an air horn 14 at its upper extremity, to which a conventional air cleaner is ordinarily attached, presenting an air intake opening 16' for the vertical air fuel passage 18. At the bottom of this passage is a wall portion 20 which, as will be presently apparent, serves the purpose of a baffle to effect proper mixing of fuel with the incoming air. The lower extremity of the body portion 12 is ofiset with relation to the passage 18 and presents a discharge opening 22 entering into the lower body portion 24 removably secured to the upper portion and constituting therewith the complete carburetor body.

Thelower body portion has an annular flange 26 for attachment tothe intake manifold of an internal combustion engine, as will be readily apparent. It will be appreciated that the provision of two body portions is optional inasmuch as the carburetor could as well be formed of integral construction. In any case, it is desired to include the offset relationship between the intake and dis- . charge'op'enings 16 and 22 as well as the intermediate bafile wall 20.' To'one side of vertical passage 18 the body is providedlwith a threaded opening 28 within which an ex- .te'rnally. threaded bushing member 30 is received. The bushing is provided with a headed external end 32 suitably formed for manipulation with a wrench, and rigidly secured to this end of the bushing is a housing formed of the two sections 34 and 36 having frictionally engaged flanges 38 and 40 respectively holding a resilient diaphragm member 42 therebetween.

A stop sleeve 44, more fully described hereinafter, is slidably received in bushing 30 and this sleeve, in turn, slidably receives the valve body 46 which terminates at ice one end adjacent the passage 18 and at the other end externally of the housing section 36, this section having an opening 48 therefor. The outer end of the valve body is grooved, as at 50, into which the inner circumference of the diaphragm is snapped. An annular pressure plate 51 is rigid with valve body in underlying relation to the central portion of the diaphragm and provides a reaction member against which the two tapered coil springs 52 and 54 act. These two springs are normally balanced, in the absence of external forces, in a position in which the pressure plate 51 is disposed centrally between the opposite ends of the housing sections 34 and 36. However, when the engine is idling, as illustrated in Figure 2, or at any time that the intake manifold vacuum is at its maximum, the diaphragm will be moved to the position shown in Figure 2 with the pressure plate 51 engaging against the stop sleeve 44, the manifold pressure being communicated to the diaphragm through a longitudinal groove 56 in the sleeve 44.

The valve body 46 is provided with a longitudinal bore 58 including the enlarged portion 60 within which the spring 62 is seated with its free end engaging against the upper end of valve core 66. The inner end of the valve body' receives the threaded plug 68 guiding the valve core through its opposite end walls 70 and 72 in the same manner as set forth in my previously mentioned prior patent. In this respect, it is to be noted that the valve core 66, its associated collar 74, the throttle valve 76, the parallel arm 78 depending from the throttle valve, and the manner of interconnection between the arms and the collar are all identical to the construction employed in my prior patent.

The pivot shaft 80 for the throttle valve is provided at one end with an arm 82, as indicated by dotted lines in Figure l, which is connected by any suitable means to the accelerator pedal of the vehicle for actuation thereby. The opposite end of the throttle valve pivot shaft has a fast idle member 84 secured thereto as by setscrew 86, and this member includes the radially projecting arm portion 88 provided with an adjusting screw 90, the purpose of which will be presently apparent.

The fast idle assembly is interconnected for simultaneous actuation with an air fuel mixture enrichening assembly for starting the engine when cold. This assembly incorporates a horizontal shaft 92, see Figure 3, journaled in the carburetor body having an eccentric projection 94 on its inner end received in a bore 96 in the stop sleeve 44. 'The outer end of shaft 92 carries a lever member 98, to one end of which a Bowden wire hand choke control 100 is connected. The opposite end of the lever is pivotally connected by member 102 to link 104 having an elongated slot 106 in its free end embracing the limit stop member 108 secured to the carburetor body.

The upper edge of the link is notched, as at 110, and in the normal position of the link the adjusting screw is disposed therein.

An abutment projection 112 is formed on the body 10 and a lever adjusting screw 114 is engaged thereagainst to vary the normal positioning of sleeve 44.

For the purpose of starting the engine, the throttle valve 76 is left in the closed position so that when the engine is cranked, a suction will be developed below the throttle valve which communicates through passage 56 with the suction side of diaphragm 42, thus moving the diaphragm from its normal position substantially midway between the ends of the housing sections 34 and 36 to the position shown in Figure 2, in abutment with bushing 44. This will of course move the valve body 46 a corresponding amount and at the same time the valve core will have moved into engagement with arms 78. These arms are so positioned that movement of the valve core is arrested before the valve body reaches its limit of travel or that point at which it engages the bushing 44, uncoverin a portion of tapered slot 116 in the 'vaive'core to permit entry of fuel into the carburetor.

If the engine is warm, the above operation will be sufficient tostart the engine. However, if the engine's cold, it will be necessary to manipulate the cableliltl'andthus shift the bushing 44 to the right in Figure 2, when will ermit further than normal travel of the diaphragm and the valve body, whichwill effect a correspondingly greater uncovering of the tapered slot 116, with a resulta nt richer mixture within the carburetor. V V H r I M U It willbe noted that theefiect of the throttle valve on the fuel airmixture on the one hand, and the eifect ofthe 'valve body on the other handite nd to counterbalance other to produce a uniform fuel air ratio over the normal operatin grange of the engine. That is, assuming a vehicle proeeeding along a level stretch of roadwayat aconstant speed, opening movement, of the throttle valvejwill shift the valve core to the left (Figure '2), while at the same time the momentary decrease in manifold vacuum (until the speed of the vehicle increases to that corresponding to the new throttle setting) will shift the valve body tothe left also, so that as a practical matter there is no relativemovement betweenthe valve core and the valve body, thus maintaining aprcdeterconstant'air fuel ratio in the carburetor. Of course, under some conditions of operation, it is possible to obtain a richer than normal mixture. For example, under full load, full throttle conditions, the diaphragm and valve body will be positioned such that the springs 52 and 54 arein eguilibrium inasmuch as no vacuum will exist in the manifold. At the same time, the full opening position of the throttle valve 76 will have shifted the valve core its full extent to the left in Figure 2 and will have passed that point which would result in the normal fuel air ratio and will thus produce a richer than normal ste During normal idling, the parts are in the position as ilh strated in Figure 2 with a portion of slot 116 uncovered At this time, the throttle valve is closed and air is supplied to the engine through the nozzle 118 which is formed as an extension of plug 120 adjacent the bottom wall or bafile 20. In the absence of other preheater means, an air cleaner 122 is positioned adj'acentthe-exhaust manifold and a line 124 leading therefrom oonn'ects to the body 120 to supply heated air to the carburetor.

'l'he bore 126 in the plug is intersected by a threaded aperture receiving an adjusting screw 128-for varying the "amount of air entering the carburetor during idling.

v ;;It is to behoted that the nozzle 118 is directed onto the bathe wall whereby the incoming air will scour this hafile-and-pick up liquid fuel deposited thereon. At anytime the engine is running, the baffle will-of cour's'e operate to thoroughly mix the fuel and air.

Thebushing 3t} is adjusted initially to obtain the proper :air fuel mixture throughout the operating range of the e'arburetorand is held in the desired position by"a=setscrew-Q0. In conjunction with the positioning oftli'e bushing 30, the sleeve 44 is likewise properly'positioned by manipulation of the adjusting screw 114. When-these twoadjustments are-properly set, the desired air fuel mixture will be obtained throughout the operating range of the engine. V H v i lt isfto betnoted that since the diaphragm 42 is not rigidly secured to the valve body but is merely received in groove-50, the housing sections 34 and 36 may be 'rotaltediwithoutimparting rotation to the valve body,,.,that is, rotated in conjunction with the nut member to eflect the initial positioning of the bushing 44. This is important inasmuch as the valve body will be connected to the fuel line and it is not desirable to rotate the valve body as the adjustment on the casings 34 and 36 is obtained to etfect the positioning of the bushing 44. There fore, as the casing sections 34 and 36 and the screw member 30 are rotated, the diaphragm 42 merely slides around the valve body since its beaded inner edge merely slides within the groove-50 previously mentioned.

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims. I

What isclaimed as new is as follows: 7

1. A suction operated control mechanism adaptedfor use in controlling the inlet of fuel inwardly of a butterfly valve in a carburetor having a body adapted to be mounted on the intake manifold of an internal combustion engine in response to variations in pressure in the intake manifold, said mechanism comprising a housing adapted to be supported on the carburetor, a valve body movably mounted on said housing andhaving a stein adapted to extend into the interior of the carburetor body, a diaphragm mounted in said housing and connected to saidvalve body for movement thereof, a sleeve c ncircling said stem and slidably supporting the same, said sleeve adapted to be movably supported in the wall of the carburetor body and extend into the interior thereof, said sleeve having one end extending into the housing and forming a limiting abutment for said diaphragm thereby limiting the movement of the valve stem, said sleeve having a longitudinal passage therein adapted to communicate the interior of the carburetor body with the housing for movement of the valve stem in response to variations in pressure in the intake manifold and adjacent portion of the carburetor body, means adapted to be mounted on the carburetor body for adjusting the longitudinal position of 'the sleevc thereby adjusting the scope of movement of the valve stem, said valve body being-hollow hardenin a fuel tn1et1passageway,a asm ar ng valve co r'e associated with the irinerendof the passage- 'way "for controlling the flow of' fuel into "the ea-reefers; bodyuponrelative movement between the valve body and the metering valvecore. a a v 2. The esmsina'tion of claim 1, said means fora djii sting the'sleeve' comprising 'apivotal member adapted to be supported on the carburetor bodya djacent the "sleeve, an eccentric-lug projecting fromsaid pivotal member, saidsle'eve having an opening receiving said lug for moving said sleeve longitudinally uponpivotal' movement-of the pivotal memberfsaid pivotal member being manually controlled.

Reliei-enc es Cited in the the of this patent UNITEDSTATES PATENTS "631,698 Cowle's 'A1 ig. 2'2,f1's9 9 2,524,446 Johnson 0ct.,,3, 19 5 0 2,598,598 Pierce May 27, "1952 2,630,249 Taylor 'Mar. "3, 2,650,981 Rockwell Aug. 25,1953 2,653,804 cedarhol'm Sept. 29, 1953

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