US2572169A - Carburetor - Google Patents

Description

M. MALLORY Oct. 23, 1951 CARBURETOR Filed Aug. 6, 1945 INVENTOR. Mar/on Ma/b/y BY Patented Oct. 23, 1951 o: STATES PAT EN T F F 1 o E CARBURETOR- Marion Mallory; Detroit, Mich?" Application August 6, 1945, Seria-1No.-'609;134

. 3 Claims. 1% Thislinveentionhrelates to .a carburetor for an internal"combustionlengine.. ItLisLthe. object of this. invention to produce a'lcarbureto'r which'will'vary the .quality orthe fuel mixture in direct relation. to variationin' the load applied to the engine.

Y Inthe ordin'arycarburetor the .quality or mixtlil'e ratio is .not. varied .in direct relation to the lo'adiofjthe engine,- because. the present day carburet'o'rs have what is .known .as the vacuum power" jet or. economizer, which is controlled en.- army-wine vacuum existing'in the intak manifoldfbetween" the carburetor throttle and the enginaLAnd whenusing this vacuum to operate a-"powerjet, it'is impossible to vary the fuel mix tureflratidinifiirect relation to the load applied toi'the'engine over the complete range from no loadto full load orclosedthrottle' to wide open throttle, because the vacuum in the intake-manifold actuallyvariesfrom 1 'inch to 25 inches oi mercm'y when"-the-vehicle* is connected to the engine; and being driven'on the road. The ram; is -thewacuum between the throttle and engine actuallvsurges' -or varies due to the slightest movement-"of-throttleor the slightest change in engine 1oacl, and"in"any 'attempt'to meter fuel with" a v metering device" throughout the entire throttle andloadrange using the manifcirld vacuum'a to control'th'e metering device; difiiculties would arise-"because the slightest movement 'of the: enginerthrottle or r the" sli'ghte'st change" in engine load would =cause the metering device to surge over the same wide range that thevacuum in-theintake manifold surged; naturally the mixture -=wou1d surge-from arichmixture" to a lean l mixture and 'from a lean "mixture to'a rich mix ture and the-engineWouldroll or surge in h'ar mony: It is'for the? abovereasons why the 'pre's ent day -power jet? or: metering: device will not meter the fuel satisfactorily over theentire throttl'eand load range; Therefore, the present day power 'jets' aresetby--spring tension to open Wh'enth'e vacuum inthe manifold dropsbelow four or six inches and to close whenthe-vacuum in' the manifold rises above-four or six inches, consequently; in thepresent day metering devices thefu'el is only metered over a small part of the throttle and load range. In otherwords, the fuel is onlyvmetere'd perhaps between 6 inches and'3 inches of vacuum; any time the mani fold vacuum is lower than 3 'inchesa full load mixture is being. delivered andany time the vacuumin the manifold isabove 6 inches of mercury a light load. mixture isbeing delivered. The presentfiay metering device merely. produces two 2... mixture conditions one rich:- .for.- full= load and onealean: for light load-.1 Naturally, there-are manymtimeswwhenv the mixture-is richer than necessary .fo'i: the "load under which the eng-ine is operating. Such metering of fuel not only results. insspottysperformance 01 the engine but it results in-poorweconomy becausean overly lean mixture results in poor economy as-well as i an overlyvrichmixture.

in myucarburetor, Ius-e. the'suc-tion between the. carbiiretor throttle'and engine, also.-the suction between the. carburetor-throttleand atmos phereflto operate. the metering device. In this manner the highmanifold vacuum between the carburetor throttle and manifold is lowered by venting "it to the lower vacuum existing-in the venturi .or. intakepassageway between the throttle and atmosphere. The orifice above the throttlenplays the ro1e-ofanrai-r bleed to the orifice below thelthrottlefland increases the air bleed effectiveness -as. theflthrottle is :moved towards a closed .position preventing thevacuum from surging to a high point-in the suctiondevicethat operates the metering. device-and viee versawhen the throttle valve starts tomove toward 'an-open position the orificeflabove' the throttle ceases to be an .airblediand becomesaasuction orifice preventihgla sudden .drop .in the vacuum existing in th'suctio'n device that operatesthemetering device. By this. methodsof operating a power jet or meteringdevice the surging vfrom-a lean mixtureito-a richfmixture andsfromfla rich mixture to-ale'an mixture is eliminated makingpossible-tli useof -a meteringdevice that will-operate" smoothlyv through. the complete range. from closed throttle to open throttle 0r. no--1oad=to-ful1 load.

Intheldr'awin gs Fig} .1 isra vertical section through my carburetort.

Fig? is. a. detail--showing-the connection betweenthe airvalve-andthrottle valve. 1

The .:parts ofmy: carburetor are referenced as fO1l0WS-Z-'- carburetor: housing I, intake passagewave-2 having'. ai-rinlet 3 and'fuel mixture outlet 4 toflthesengine =intake-mani=fold; throttle valve 5 and-airvalve-t; throttlevalveshaft I and ai-r valve shaft 8 both -journalled in housing 1| cranks 9 and I0 fixed on shafts l and 8, respectively, linl =:i I connecting-cranks 9 and I D so that valves 5 and-e6 open-and 5010560111 unison;- crankl 2 fixed on shaft-l, rod! 3 connected to crank H for manuallyecon-trolli-ng the throttle-valve 5 and air valve B cranksl l -journalled-onshaf-t- *and-Jreely roitatable -relative to shaft 1 ,3 rod l 5 :;C01'1I180ti11 crank 4 with diaphragm lb of suction device l1, suction chamber |8, conduit l9 connecting suction chamber l8 with orifice 20 in venturi 22, conduit 23 connecting conduit H! with orifice 24 on the engine or outlet side of throttle valve 5, adjustable needle valve 25 for adjusting the effective size of orifice 24, tension spring 26 an-. chored to post 21 on crank l4 and to post 28 on plate 29, pivot 30 for plate 29, set screw 3| in arcuate slot 32 for holding plate 29 in adjusted position, float chamber 33, fuel level 34, metering pin 35 having the usual tapered face 36, link 31 connecting pin 35 with crank I6, booster venturi 38, metering orifice 39, fuel passageway 40 connecting metering orifice 39 with fuel jet 4| in venturi 38, air bleed 42 to prevent fuel from siphoning out of bowl 33 into the engine, pump plunger 43 connected by link 44 to crank I4, pump cylinder 45, passageway 46 connecting cylinder 45 with venturi 38.

The operation of my device is as follows: Assuming the engine is idling, as shown in Fig. 1, valves and 5 will be nearly closed and the vacuum will not be as high in suction chamber 8 as it is in the manifold at orifice 24 because orifice 20 in the venturi is in a higher pressure and bleeds down the high manifold vacuum. Valve 25 will be adjusted so that at idle the vacuum established in chamber l8 will move diaphragm Hi to the left, in the position shown, which acts through rod l5, crank i4 and link 3'! to bring the tapered or fiat portion 36 of metering pin 35 in correct position with orifice 39 so as to admit the correct amount of fuel through orifice 39 into the mixing chamber for idle. If throttle valves 5 and 6 are now moved toward an open position, the vacuum will drop at orifice 24 but the velocity of the fuel mixture by orifice 20 will induce a vac: uum at orifice 29 which will prevent such a sudden drop of vacuum in chamber H3. The metering pin will move toward an open position smoothly instead of flying wide open abruptly as it would if it were not for orifice 20. If metering pin 35 flew open abruptly, the mixture would go too rich and it would be impossible to obtain proper opening of the metering pin if only orifice 24 were used. As throttle valves 5 and 6 move further toward open position vacuum decreases at orifice 24 and in suction chamber i8 permitting spring 25 to move metering pin 35 upwardly to increase the mixture richness. It should be borne in mind that the metering pin is controlled by suction device I! independently of throttles 5 and 6 which are controlled manually or through the usual accelerator pedal. If the throttle is held at one position between wide open and closed and the load on the engine is decreased or increased due to the vehicle going down grade or up grade, the vacuum in suction chamber l8 will increase or decrease and the metering pin will move to give the engine the proper mixtures for either the light load when going down grade or the heavier load when going up grade. With my arrangement the metering pin substantially follows the vacuum from a point when the vacuum is the highest at no load to a point when the vacuum is the lowest at full load.

Another feature of my carburetor is this: Metering pin 35, and in particular the flat tapered surface 36, is mounted with respect to orifice 39 so that when the vehicle is decelerating and the vehicle is driving the engine to thereby cause the vacuum at orifices-24 and 20 to be higher than the idle vacuum, the vacuum established in chamber l8 will be high enough to cause metering pin 35 to completely close orifice 39 and prevent any fuel from entering the engine as long as on deceleration and the vacuum is higher than idle vacuum. Thus, with my carburetor I shut 01f both the idle and main fuel jet 39 whenever the vacuum upon deceleration of the vehicle at orifice 4| becomes higher than the idle vacuum. This is an advantage because otherwise under such conditions there would be a slight feeding of fuel out of the main jet of the venturi which would be too lean a mixture for good combustion and would simply burn in the exhaust pipe or muiiler and create obnoxious gases which would find their way into the vehicle and also cause a waste of fuel.

As throttle valve 5 moves toward closed position orifice 20 plays the role of an air bleed to orifice 24 and when valve 5 moves toward open position orifice 2U ceases to be an air bleed to orifice 24 and becomes a suction orifice. Due to this interplay of orifices 20 and 24, the vacuum in suction chamber l8 never equals the vacuum which obtains in the intake passageway on the engine side of valve 5. Byway of example and not by way of limitation, the vacuum in chamber |8 never reaches over ten or'twelve inches of mercury. The mixture richness is actually metered according to the vacuum under which the engine is running so that as the load decreases the mixture gets leaner and vice versa. The tension of spring 26 can be adjustedby loosening screw 3| and swinging lever 29 about pivot 30 either upwardly or downwardly and then resetting screw 3| in adjusted position. By adjusting this spring the mixture ratio can be varied.

Although I have shown my fuel metering system in connection with a mechanically operated air valve carburetor, I do not wish to be limited to the use of my metering system in this type of carburetor. The metering system can be used with a single valve carburetor having no air valve.

For purposes of description, fuel is drawn through jet 4| by the intake passageway suction but it is understood that fuel could be injected through jet 4| by positive pressure such as by means of an injection pump. Thus, my invention contemplates discharging the fuel out of fuel jet 4| either by suction or pressure.

I claim:

1. In a carburetor for an internal combustion engine, said carburetor having an intake passageway therethrough, a throttle valve in said intake passage, a fuel-passageway discharging into said intake passageway on the atmosphere side of said throttle valve and having a metering orifice, metering means having a uniformly tapered surface which cooperates with said metering orifice for gradually varying the efiective size of said metering orifice, a first orifice in the wall of said intake passageway on the atmosphere side of said throttle valve, a second orifice in the wall of said intake passageway on the fuel mixture outlet side of said throttle valve, pressure actuated means, a passageway connecting said first and second orifices with each other and with said pressure actuated means, a connection between said pressure actuated means and said metering means, resilient means operatively connected to said metering means and tending to move said metering means to increase the effective size of said metering orifice, said pressure actuated means respondingto an intermediate pressure resulting from a blending of the pressures obtaining in the intake passageway at said first and second orifices, the said pressure actuated means responding to a fall in said resultant pressure to decrease the effective size of said metering orifice and to an increase in said resultant pressure to increase the effective size of said metering orifice, said first orifice acting as an air bleed to said second orifice as the throttle valve approaches closed position and as said throttle valve moves from idle toward open position said first orifice ceases to be an air bleed orifice and becomes a suction orifice due to the increased fiuid fiow through said intake passageway by said first orifice, said metering means and metering orifice being constructed and arranged whereby when the vacuum in said pressure actuated means exceeds the idle vacuum obtaining in the intake passageway on the engine side of the throttle valve when in idle position the said pressure actuated means will respond to said vacuum and close said metering orifice to completely shut off the flow of fuel therethrough, and an air valve positioned in the intake passageway on the atmosphere side of both the throttle valve and the point at which the fuel is discharged into the intake passageway, and means connecting said air and throttle valves so that they open and close substantially in unison.

2. In a carburetor for an internal combustion engine, said carburetor having an intake passageway therethrough, a throttle valve in said intake passageway, a fuel passageway discharging into said intake passageway on the atmosphere side of said throttle valve and having a metering orifice, a metering valve for varying the effective size of said metering orifice, a first orifice in the wall of said intake passageway on the atmosphere side of said throttle valve, a second orifice in the wall of said intake passageway on the fuel mixture outlet side of said throttle valve, pressure actuated means, linkage mechanism connecting the metering valve to said pressure actuated means, said pressure actuated means including a suction chamber and a diaphragm movable in a first direction in response to a fall in pressure in said suction chamber to close the metering valve and movable in a second and opposite direction upon a rise in pressure in said suction chamber to open the metering valve and resilient means operatively connected to, and applying a force on, said diaphragm in said second direction, and a passageway connecting said first and second orifices with each other and with the suction chamber of said pressure actuated means, the above construction and arrangement being such that the intermediate pressures resulting from a blending of the pressures obtaining in the intake passageway at said first and second orifices apply force on said diaphragm in opposition to said resilient means and movement of the diaphragm as aforesaid acts through said linkage mechanism to effect closing and opening movement of the metering valve to decrease and to increase respectively the effective size of said metering orifice.

3. In a carburetor for an internal combustion engine, said carburetor having an intake passageway therethrough, a throttle valve in said intake passageway, a metering orifice in the intake passageway on the atmosphere side of said throttle valve through which fuel is discharged into said intake passageway, a fuel passageway between said source of fuel and metering orifice, a metering valve having a tapered face cooperating with said metering orifice for varying the effective size of said metering orifice, a first orifice in the wall of said intake passageway on the atmosphere side of said throttle valve, a second orifice in the wall of said intake passageway on the fuel mixture outlet side of said throttle valve, a single pressure actuated means actuated solely by the suction obtaining in said intake passageway at said first and second orifices as specified below, said pressure actuated means being the sole means for opening and closing said metering valve, linkage mechanism connecting the metering valve to said pressure actuated means, said pressure actuated means including a suction chamber and a diaphragm movable in a first direction in response to a fall in pressure in said suction chamber to close the metering valve and movable in a second and opposite direction upon a rise in pressure in said suction chamber to open the metering valve and resilient means operatively connected to, and applying a force on, said diaphragm in said second direction, and a passageway connecting said first and second orifices with each other and with the suction chamber of said pressure actuated means, the above construction and arrangement being such that the intermediate pressures resulting from a blending of the pressures obtaining in the intake passageway at said first and second orifices apply force on said diaphragm in opposition to said resilient means and movement of the diaphragm as aforesaid acts through said linkage mechanism to effect closing and opening movement of the metering valve to decrease and to increase respectively the effective size of said metering orifice.

MARION MALLORY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,841,778 Beatson Jan. 19, 1932 1,850,307 Moore Mar. 22, 1932 1,945,200 Mock Jan. 30, 1934 2,182,090 Mallory Dec. 5, 1939 2,232,392 Kittler Feb. 18, 1941 2,316,327 Garretson Apr. 13, 1943 2,361,227 Mock Oct. 24, 1944 2,392,055 Mennesson Jan. 1, 1946

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