US2722207A

US2722207A - Multiple stage carburetor

Info

Publication number: US2722207A
Application number: US396982A
Authority: US
Inventors: Jorma O Sarto
Original assignee: Chrysler Corp
Current assignee: Old Carco LLC
Priority date: 1953-12-08
Filing date: 1953-12-08
Publication date: 1955-11-01
Anticipated expiration: 1972-11-01

Description

MULTIPLE STAGE CARBURETOR Filed Deo. 8, 1955 6 Sheets-Sheet l 6 Sheets-Sheet 2 Filed Dec. 8, 1953 INVENTOR. Jrn/4 d, Sarita Nov. 1, 1955 J. o. SARTO 2,722,207

MULTIPLE STAGE CARBURETOR Filed Dec. 8, 1953 6 Sheets-Sheet 5 I N V EN TOR. J2 f77/4 $47214 Z BY fr fa )wwf/g Nov. 1, y1955 J. o. sAR'ro MULTIPLE STAGE CARBURETOR Filed Dec. 8, 1953 e sheets-sheet 4 f Y l )Ahh l 7&5#

IN V EN TOR.

72777774 Saffo MMM Nov. l, 1955 J. o. sARTo 2,722,207

MULTIPLE STAGE CARBURETOR Filed Dec. 8, 1953 6 Sheets-Sheet 5 INVENTOR. L75 77774 Se 7'210 MMM Nov. l, 1955 J. o. sARTO MULTIPLE STAGE CARBURETOR 6 Sheets-Sheet 6 Filed Dec. 8, 1953 MM MM 4/.e/c# 4 4 M a l 4 w f o i M M 5 m1@ l M f m5 A y 0. el l m 2 w ,w www JW f. j/V/7 M f f y M @Z y@ i j United States Patent() MULTIPLE .STAGE cARBURET-.OR

ApplicatiomDecemberzS, 19153, Serial No..396,^9.82

3S Claims. .(Cl. '12S-#127.)

This kinvention :relates to multiple stage liquid fuel carburetors for internal combustion engines and :more particularly toa means for. controlling the .actuation of an auxiliary carburetor stage -of a multiple stage carburetorin response to engine speed. f

The characteristics of a conventional internal' .comibustion engine equipped with a .liquid Afuel carburetor .are such that the :engine output .torque will kvary with -a lvariation in engine speed. 'This variation .in .engine torqueis caused by a `numberof factors, one of .which is the change in the fuel vmixing characteristics .of the cara fburetor which accompanies "a variation `in v:engine speed rdesign. .As the engine `speed increases,:the;intake airiflow rate within the ycarburetor fuel .fmixing throat is also increased. When ya lsingle stage .carburetor zisaused, the air dl'ow .rate *which would produce Sthe .optimum fuel mixing .characteristics .in .the :single mixing throat tthereof willrnor- :mally occur throughout .a low engine .speed range. .At .arelatively .higher feng'ine speed range the :mixing char- .acteristics :and air .fuel ratio may :deviate from :the I.optimum .and for this reason the engine .output torque will normally .tend to .decreasew'ith an'increase in engine fspeed.

tlf a dual barrel carburetor iis employed, `and Tiif :both ofthe 'mixing throats are operative :over .the entire engine speedrange the air tlow -rate l,which would teXist Iin veach :of the `.throats 4at .low engine speeds "would '.'be 5such athat the mixing characteristics would :be .relatively rpoor. On the yother jhand, the :correct .iow .rate may exist .at the higher lengine rspeeds. .'lhus, :.the engine :output itorque will .tend'to'increa'se withan increase :in the .engine speed .throughout Aa substantial fportion zof 'the noverall Lspeed range below the `output :torque ibegins ;to Afall ofI or ;d e

crease.

Accordingly, .it has been foundrdesrableito render xthe secondary l'stage -of a dual :carburetor zinstallation :inoperative lat the' lower engine fspeeds and nto :render -the Vsame operative .at1hgherfengine speeds. ,The dual :carburetor unit will, therefore, function -as asinglerstagercarburetor over the lower engine speed range ;and the secondary ystage :thereof will funct-ionzonly. at .the highery engine :speed range thusmaking it possible toftake .advantage of 1the resulting optimum mixing characteristics-forrboth stages .toobtain a lmaximum Venginepoutput torque -over ,the entire speed-range.

It .is desirable to provide .an automatic :meansl ifor controlling the secondary ,stage .to-.causezthe :same :to '.be ac- Vtuated/at .fthe fproper engine '-speed. vzlnrorder-to :avoid a sudden change :in ,the .magnitude :of the output torque, :it is :necessary tto `actuate ,fthe secondarystage fat anengine speed 'suchthat the engine output torque :during engine operation with only thel primary stagewillbe substantially the same as :the .engine .output itorque ;during=operation with -bothscarburetory stages.

-lnorder .that the controlmeans for :the secondary stage .mightbe actuated at the,proper-engine'speed,;itfis necessary .to ,obtain an engine speed signal .tofinitiate .the automatic controlresponse .In the presentembodment ,such a speed signal may consist of the engine coolant pump 'Cil Aice

discharge :pressure Awhich in turn is proportional .to engine *speed .since tthe coolant pump is normally lpowered Adirectly lbyfthefengine. e

.A :primary .object .of the present invention is to provide ra means which is `responsiveto .engine speed for-control.- ling .fthe .operation of the .second stage -of a'two-stagecar- :buretor 'so A.that the second :stage will be inoperative at `low'engine vspeeds .and operative at 'higherengine speeds.

A more specic :object of the present :invention is to provide :a means which is responsive to engine coolant .pump pressure to automatically control thesecond stage .of atwo-stage carburetor whereby the second :stage thereof :is rendered `operative fat speeds above .a lpredetermined 'maximum .value :and at a predetermined y.range :of throttle positions.

`Another .object of the present invention .is 'to .provide an .automatic :control rfor -a multiple stage 4carburetor fac- Acoi-.ding .to .the precedingtobjects wherein a means is pro- `.vided .for connecting 'the throttle valves of the secondary .stage with-the .throttle .valves in ,the primary stage during movement .tof the aprimary .throttle Valve throughout -a range :of zpos'itions mear the wide lopen vthrottle position. The primary throttle valve may 1in .turn be :actuated manually. i

.Another :object :of :the present invention is to Lprovide .an :automatic :control :for a Amultiple stage carburetor iaccording to the preceding object wherein an engine speed :responsive device :associated lwith ythe automatic -control -is fadapted to :adjust ythe :position Iof the secondary :throttle valve actuating linkage at engine speeds above -a prede- :termined :value 'to :permit the linkage to befcontacted by .a .corresponding linkage `for the primary lthrottle vValve duri-ng movement fof lthe primary throttle :valve through- :out fa ipredetermined vrange of positions thereby 'providing :for `an adjustment ofthe lfuel-air ratio over the throttle yspeed-.range` off fthe ysecondary stage.

Another .object .of the 4.present invention Vis to provide an automatic control means according to .the Lpreceding yobject wherein the speed responsive device comprises an .engine coolant pumppressure responsive actuator-anda ".snap Y:type :valve :interposed in va -uid conduit 'between -the :pressure .responsive actuator and the engine'coolant pump, the said snap type valve being'e'lectiveto cause 'the actuator .tobe positively and ifully actuatedisubstantially Ainstantaneously `when the pump pressure reaches a predetermined value.

Another io'bject of the Kpresent `invention is Vto provide an automaticxcontrolfor a multiple stage carburetorwhich :is responsive'to engine speed and which comprises `an Vengine Aspeed @responsive actuator positively A connected to 'an auxiliary stage=valve.

Another object of the present yinvention is `to provide fan automatic :control fas set forth in the `preceding object fwherein the.engine.speed signal for the speed responsive actuator is obtained from the engine coolant pump ypres- :sure .and :wherein .a :fluid conduit -is rprovided between the actuator and the engine coolant pump. Auid control fvalve l'is interposed 'in the conduit and actuated by 'meansof theprimaryy throttle assembly.

In :.general, the `present invention as herein disclosed, comprisesa Vcarburetor having a'pair of primary fueljmix yingrbarrelsvand a pair o'fauxiliary'barrels which Vare "associated with the primary and secondary stages respectively. Each of vvthe barrels is provided with a throttlelvalve :for .controlling rthe intake :air lflow rates therethrough. The throttle valves :for-.theprimary stage are mounted fin tandem -upon ,a ,common shaft and the throttle valves for lthe.secondary-stage :are also mounted .in tandem 4upon another common shaft. The lprimary vthrottle -shaft is positively linked to a .manually actuated -foot throttle lever and another portion of the,primary 'throttlefshaft carries a lost motion element which is adapted to contact J a mating lost motion element pivotally carried by a lever which in turn is connected to the secondary throttle shaft.

A coolant pump pressure responsive actuator is mounted upon the carburetor and is linked to the pivoted lost motion element. Upon reaching a predetermined value the coolant pump pressure causes the actuator `to move its associated lost motion element into `a position in the path of movement of the other lost motion element as the primary throttle valve moves toward the wide open position. Therefore, the primary throttle valve linkage is adapted to control the opening of the secondary throttle during movement of the primary throttle valve throughout a predetermined operating range and when the speed of the engine exceeds a predetermined minimum value.

According to another embodiment of the invention a coolant pump pressure responsive actuator is provided on a four-barrel carburetor and the movable element of the actuator is positively linked to the secondary throttle shaft to actuate the same when the speed of the engine reaches a predetermined minimum. No direct mechanical connection is provided between the primary and secondary valves in this embodiment. However, the movement of the primary valve is effective to control the movement of a control valve which regulates the delivery of coolant pressure from the coolant pump to the actuator.

For the purpose of more particularly describing the present invention, reference will be made to the accompanying drawings in which:

Figure 1 is a top view of a four-barrel carburetor equipped with the second stage control of the present invention;

Figure 2 is a side view of the carburetor of Figure 1 showing a portion of the linkage associated with the primary and secondary stages;

Figure 3 is a bottom view of the carburetor of Figure 1;

Figure 4 is a side view of the carburetor of Figure 1 showing the side opposite from that shown in Figure 2;

Figures 5, 6, and 7 are perspective views of the throttle valves and the associated control levers. Each of the views shows the levers in relatively different positions for the purpose of more clearly illustrating the operation of the invention;

Figures 8 and 9 schematically show a modified arrangement of the control levers for the throttle valves. The coolant pump pressure responsive actuator is shown in the deenergized position in Figure 8 and in the energized position in Figure 9;

Figure l is a schematic showing of another embodiment of the present invention which is similar to the ernbodiment of Figures 1 through 7;

Figure ll is a schematic representation of still another embodiment of the invention in which the coolant pump pressure responsive actuator is directly coupled to the secondary throttle shaft to actuate the same and in which the fluid conduit leading to the actuator includes a quick action flow control valve;

Figure l2 is an alternative form of a flow control valve which may be used with any of the presently disclosed embodiments; and

Figure 13 is another modified form of the invention having a flow control valve of a third form.

Referring first to the plan view of Figure l, the construction is designated generally by numeral 10 and, it includes four barrels which are separately identified by means of

numerals

12, 14, 16, and 18. The four barrels are divided into pairs of two by a vertical transversely extending wall 70 which forms an integral part of the carburetor upper cast structure 22. The

barrels

12 and 14 are grouped together on one side of wall 70 and the barrels 16 and 18 are grouped into separate pairs on the opposite side of wall 20. It will be seen from the following description that the pair of

barrels

12 and 14 are associated with the primary stage and the pair of barrels 16 and 18 are associated with the secondary stage.

An automatic choke is shown generally at 24 and iS adapted to receive exhaust manifold air through the fitting 26. A shaft 28 extends from the choke device 24 through a suitable mounting portion 30 on the casting 22 into the space above the

barrels

12 and 14 and is adapted to be rotatably adjusted by the choke device 24. A choke valve 32 is secured to the shaft 8 and is adapted to provide a choking action when the shaft 28 is rotated. The choke valve 32 is shown in the fully open position in Figure l. The shaft 28 has an extension shown at 34 which carries linkage elements for causing shaft 28 to move a slight amount when the primary throttle valve reaches the wide open position.

The presently disclosed carburetor also includes metering jets and an accelerator pump boosting mechanism which are housed in a portion of the casting 22 shown at 36. Suitable linkage elements are provided for positively connecting thhe throttle linkage mechanism with a shaft 38 which is rotatably mounted in a portion 40 of the casting 22 and which is effective to control the elements within the casting portion 36.

A fuel inlet fitting is seen at 42 through which liquid fuel is admitted to a fuel bowl, not shown.

A venturi element is centrally disposed individually in each of the carburetor barrels and are designated by numerals 44, 46, 48, and 50. Each of the venturis has a fuel jet disposed therein, as seen at 52, 54, 56, and S8 respectively which are each adapted to discharge liquid fuel into the intake air stream which flows through the barrels during operation of the engine.

In the bottom view of Figure 3 the throttle valves are clearly shown disposed in the downdraft end of the

barrels

12, 14, 16 and 18 and are separately designated by means of

numerals

60, 62, 64, and 66, respectively. The downdraft portions of the four barrels are formed in a second carburetor cast housing structure generally designated by numeral S9. The casting 59 is secured to the upper casting 22 previously described.

The pair of

valves

60 and 62, which are secured to a primary throttle shaft 68, comprise the primary throttle valves and the remaining

valves

64 and 66, which are secured to a secondary throttle shaft 70, comprise the secondary throttle valves. A suitable linkage element 72, which forms a part of the throttle linkage mechanism, is positively connected to the primary throttle valve shaft 68 in a suitable manner.

AReferring next to the side view of Figure 4, the linkage element 72 and the associated linkage elements are shown in more particular detail. The element 22 has formed thereon suitable eyelets 74 which are adapted to receive portions of a suitable manually actuated throttle linkage mechanism. The element 72 is also linked to a lever 76 by means of linkage element 78 thereby causing the shaft38, upon which lever 76 is secured, to move in response to primary throttle movement. The movement of shaft 38 is effective to control the metering jets and the accelerator pumping mechanism housed within casting portion 36.

Link elements 80 and 82 operatively connect the choke valve shaft 28 with another link element 84 which is rotatably mounted upon a portion of the casting portion 59. A lost motion connection is provided at 86 between the element 84 and another element 88 which is mounted concentrically with respect to element 84 and which is also rotatable about the common axis.

An abutment element is provided at on the primary throttle linkage element 72 and is adapted to contact the element 88 when'the primary throttle shaft 68 and the integral element 72 are rotated to a position which is close to the full throttle position. Upon further movement of the element 72 toward the full or wide open throttle position, the element 88 will be caused to rotate which in turn causes the element 84 to rotate in the same direction by virtue of the lost motion connection 84. If at this time the choke valve 32 is closed, the movement of element 84 will cause the links 82 and 8( l apre-'aow to move the choke valve to a partially open position. lIf the choke valve has been opened by the thermostatic device 24, the slack in the iost motion connection 86 is increased and therefore any movement of element 88 'by element 72 will have no effect upon the .position 'of Jelement 84.

The element 88 is also provided with a cam surface 92 which is adapted to be contacted by an adjustable stop 'device 94 carried by the element 72. When the c'hok'e valve 32 lis in the closed position, the cam 92 and stop 94 prevent the primary throttle from fully closing. Also, if the primary throttle is fully `closed v-when 'the choke valve 32 is open, the cam 92 and stop 94 'are effective to prevent the choke valve from subseyquent'ly moving to the fully closed position.

Referring'next to the side lview of Figure 2, it is vseen "that a'bracket y:96 is secured by means of screws 98 to a flange portion l*100 of the vupper casting portion 22. AThe bracket i96 has la 'main portion thereof disposed in La substantially'vertical plane alongside 4the lower casting 'portion 59.

'Theend portion of bracket 96 is `bent at a right angle fto the-1main portion l96 and is shown at 100. A pressure responsive actuator device 102, which is shown Lp'a'rt'lfyincross vsection in Figure 2, is secured to the end l-bracket portion 100 -by means of a suitable Athreaded 1adaptor and nut 104.

`The -device 102 includes a housing 1506 which may include one ore more "flexible 'diaphragms 1508 which 'extend xtransversely across the interior -of l'the "casting T06. The peripheral -portion of t'he'diaph'rag'm L108 may 'fb'e secured between the axial ends of the housing '106 fand suitable en'd caps -110 'and 112. "If a -double dia- '-p'lira'grn actuator is used, as yin -theI disclosed "embodiment, `a suitable partition wall -114 may be provided -to separate the diaphragms into a pair of working chambers.

-An --actuator shaft 116 maybe slidably received Vwithin 'the end cap 110 and the partition wall 108 vand secured to the 'central portion of each diaphragm 108. The shaft E11`1-"6-extenrls transversely through-thebracket portion 100 "and the adaptor andnut 104 in -parallel relationship with v1respect to-the bracket portion 96. The 'end'of shaft 1`16I-'carri`es va shoulder member v113 which may be sli'dra'lilyldisposed around the shaft '116 adjacent a -nut A120 which is threadably carriedby the end*of shaft116.

Aspring 119 surrounds shafts -1'16 and is interposed 'lbetweenthe shoulder 118 and the nut 104 thereby urging vthe shaft 116 in an outward direction away lfrorn vthe 'device `102.

Allink element 122 is adapted to interconnect-thefend -of-lshaft 1:16 and one arm ofaibell crank 124which is pivotally mounted to the bracket portion 96. nThe other arm ofthe'bellrcrank 124 is linked toa control-element 31256`by1means fof .the link element 128.

.Anabu'tment portion 130 is carried by the element V126 -attoneside of the connection between elements l12S and 126. A control element 132 Lis rotatably connected to th'ef'element i126 -at l134 on the other side ofthe 'abovemention'ed connection between felements 128 and y1-26. VT he control element 132 is xed to one end ofthe secondary throttle shaft 70 which extends through `the side -of=the lower casting portion 59.

VThe primary throttle shaft 68, which also fextends lthrough .the "side of the 'casting portion S9, carries an arm 136 which carries an abutmentmember 138 at one lendlthereof The member 138 is pivoted to the end of -arm 1'36 upon a suitable fastener 140 and is'urged toward Va .xedpositionrelative to the arm 136 by means of an -otset 'spring means 142.

,A .stop v144 `may be formed on the lower casting por- `tion v59 to contact a mating shoulder 146 formed on the :element 132 when thesecondary throttle reaches the fully .elosed'positionl AA suitable "spring means maybe pro- 6 nis not v"functioning to `regulate the .auxiliary .stage of the carburetor. A portion of such a spring means .may "be v.seeninFigurelZ'at148. v

The pressure responsive `actuator device .102 .may vbe 'provided with .suitable conduits 150 'and '1'52 which may be connected `to the discharge side and the intake side, respectively, of 'the .coolant ,pump 'for 'the internal lcombustion engine with which 'the present carburetor is adapted 'to ibe used. A quick action control valve,`whith will subsequently be described with reference to the other embodiments of the present invention, may 'be interposed in `the 'iluid 4conduits interconnecting the .device 'I0-2 and "the engine coolant pump.

The operation of the embodiment of Figures 1 .through 4 may best be described with reference to the perspective views of 'the throttle `valve control .elements shown in 'Figures 5, 6, .and '7. 4During `low speed operation of 'the engine, the engine coolant pump `pressure., which is,p1'-o 'portion'al "to engine speed, 'acts against one of '.the diaphragms 108 through the conduit 15.0 but the force .exerted upon 'the diaphragm `-10`8 by the coolant ,pressure is in'sucient at 'the lower -eng'in'e speed ranges to overcome the 'force exerted vby spring v119. Thus the` shaft 11'6 remains 'stationary inthe .position shownin Figure 5.

Upon movement of 'the .primary throttle toward the open position through .a manually actuated throttledikage, the arm 136 is adapted to rotate with 'the.primary throttle shaft Ifrom the `position shown in "Figure 2 to `that shown in Figure "5. When the wide openposition A-is reached .ifor the ,primary throttle, the arm and Vthe member 138 assume the position shown inFigure'S which shows the member 138 in close ,.proximityto .thefa'bub ment portion 130. 'The secondary throttle 'valves .are maintained ina close'dposition throughout this low speed operation.

l'During 'operation of 'the engine throughout a higher speed range,'th'e engine coolant pressure may increase 'to asu'icien'tly high `value to cause Ythe Vdiaphragms 108 `to `move 'the shaft '116 axially against 'the force exerted A"by the spring 119. This 'movement of the shaft '11'6 causes 'the "bell 'crank'to rotate 'about its pivot point 'thus'.causing the element "126 -to rotate about the connection .134

' 'to' an upward positionas shown'inFigure.4

-videdforrresiliently urging the shoulder 146 against the stop 144 to keep the secondary throttle closed when it When the primary throttle valves are moved toward r the Iwide open position 'during thisfhigh speed engine operation `the member '138 will contact 'the 'abutment 13.0 1beforeithefully openprimary throttle position .is reached. `-Upon further 'movement of .the .primary .throttle 'toward lthe 'wide open position 'the arm 136 and member 138 willlthencause the element `176 to rotate about ,itspivotal connection 'withthe link '128thuscausing the connection 134 at theotherend of "element 126'to move in an up- `ward direction. This upwardlmovemen't causes thesecondary throttle valve to openby virtue of the connecting lelement '132.

The lvalves andvalve control elements, as seen`in Fig `ure 6, are shown in the positions each assumes at lthe instant that the'member 138 contacts the abutment 130. 'The shaft V11'6 is yshown in 'the operativeposition it as- -sumes when the pressure responsive device 102 is energized. The spring 119 is shown in the compressed posi- :tion --and the element 126 v:is vrotated about the connecltion i134 which causes the fulcrum point .for 'the element, `namel-y, the-'connectionwith link`128, to be shiftedin 'an upward direction.

f'Upon continued'movement of'the vprimary throttle .to 4'the full throttle position while the device 102 is thus fenergizellfthevalves and control leverseach assume the `position shown in Figure/7. The arm 136 and member 1`^3`8|cause the element 1'2'6`to-rotate about its connection 'with liri'k 5128 which causes the secondary vvalves .60 an'd '62tto'cpen- Referring 'next 'to Figures *8 and 9, `a modified 'linkage arrangement' is jillustrated schematically. `The primary 'throttle 'barrelis shown at 202 and the secondarybarrel is shown at 204. A primary valve 206 is rotatably disposed within the primary barrel 202 and a secondary valve 208 is similarly disposed in barrel 204. The primary throttle valve 206 may be actuated by means of a suitable linkage such as that shown at 210, 212, 214, 216, and 218. The component 218 of the linkage may be manually actuated in the usual manner.

. The linkage component 210 is linked to a lever 220 by element 222 which is joined to lever 220 at a substantially central position. The lever 220 is connected at 224 at one end thereof to shaft 116 of the device 102 previously described in connection with the embodiment of Figures 1 through 7. The free end 226 of the lever 220 is adapted to swing in an arc which is included by the angle 0.

The secondary throttle valve 208 is secured to a linkage element 228 which is biased in a valve closing direction by a spring 230. A projection 229 is fixed to the element 228 in the path of movement of the end 226 of lever 220.

The engine coolant pump is shown schematically at 232 and a high pressure pump discharge conduit is shown at 234. The conduit 234 extends to a quick action control valve 236 which comprises a two-part housing 238 having an interior cavity 240 within which a ball 242 is adapted to freely move. The ball 242 may be formed of steel or any other suitable material.

Another fluid conduit 244 is connected to one end of the valve housing 238 and extends to the end cap 112 of the device 102 thus establishing fluid communication between the valve interior 240 and a working chamber within one portion of the device 102. A branch conduit 246 is effective to establish communication between conduit 244 and the low pressure intake side of the pump 232.

The conduits 234 and 244 are connected to the valve housing 238 at opposite ends thereof in coaxial alignment. Another conduit 248 is connected with the housing 238 at a point intermediate the connections with conduits 234 and 244. Conduit 248 extends to the end cap 110 of the device 112 thus establishing fluid communication between the interior 240 of valve housing 238 and another working chamber within another portion of the device 102.

The operation of the embodiment of Figures 8 and 9 of the linkage component 210 which in turn causes the P lever 220 to oscillate about the connection 224. The resulting movement of the free end 226 of lever 220 is insufiicient to cause contact between the same and the projection 229 on element 228.

As the engine speed increases, the ow through the valve 236 and the

coolant

234, 244 and 246 is also increased. At a predetermined engine speed the ow rate is of a suflicient magnitude to cause the ball 242 to be raised within the interior 240 thereby blocking off the connection with conduit 244. At this instant the pressure in the valve interior 238 and line 248 will build up and is in turn communicated to the device 102. This pressure acts upon one of the diaphragms 108 thus causing the actuator shaft 116 to shift toward the device 102 against the force exerted by spring 119.

The lever 220 assumes the position shown in Figure 9 at the instant the device 102 is energized. The end 226 is thereupon brought into close proximity to the projection 229 on element 228. Upon movement of the primary throttle valve to a predetermined position after the device 102 is energized, the lost motion gap between the projection 229 and the end 226 is closed. Upon further movement of the primary throttle toward the inside open position the secondary throttle valves 208 are opened.

Referring next to the embodiment of Figure 10, a moditied linkage arrangement is shown. The primary barrel is shown at 302 and the secondary barrel is shown at 304. A primary throttle valve is shown at 306 pivotally mounted within barrel 302 and a secondary throttle valve is shown at 308 pivotally mounted within barrel 304. A lever 310 is secured to the primary throttle valve and is manually actuated by means of the usual throttle linkage.

A lever 320 interconnects one end of the actuator shaft 116 of the pressure responsive device 102 and one end of link 322. The other end of link 322 is joined to the lever 310.

The secondary throttle valve 308 is secured to an element 328 which has a projecting portion 376 at one end thereof. An element 324 is rotatably mounted upon the secondary throttle valve shaft at one end thereof and the other end is connected to the central portion of lever 320 by link element 332. The secondary throttle valve is biased toward the closed position by a spring 330.

In the operation of the embodiment of Figure 10, the movement of the primary throttle valve causes the lever 320 to oscillate about its connection with shaft 116 which causes the element 324 to oscillate about the secondary throttle shaft by virtue of the connection between lever 220 and element 324.

When the engine is operating below a predetermined speed the position of the shaft 116 is as shown in Figure 10. Under these conditions the oscillatory movement of element 324 is insufficient to cause Contact between the same and the projecting portion 329 on element 328. However, when the device is actuated in the manner previously explained the shaft 116 is shifted so as to move the element 324 into closer proximity to the projecting portion 329. Upon subsequent movement of the primary throttle beyond a predetermined setting the element 324 will then Contact portion 329 and cause the secondary throttle valve 308 to open.

Referring next to Figure ll, another embodiment is shown wherein the pressure responsive device 102, previously described, is utilized to directly actuate the secondary throttle valve. As seen in the figure, the actuator shaft 116 of the device 102 is directly connected to an element 402 which in turn is xed to the secondary throttle shaft. Movement of the shaft 116 will therefore cause the secondary throttle valve, shown at 424, to oscillate within the secondary barrel, shown at 406.

The primary barrel is shown at 408 and has mounted thereon a primary throttle valve 410. A carn element 412 is secured to the primary throttle shaft at one end thereof in a convenient location. A suitable manually actuated throttle linkage is provided at 414, 416, and 418 and is operatively connected to the primary throttle in the usual manner to actuate the same.

A cam follower 420 is suitably mounted upon an actuator rod 422 which may be slidably disposed within any convenient structure either on the carburetor casting itself or at a location remote thereto as desired. The rod and cam follower are biased toward the cam 412 so that the cam follower is maintained in contact with the cam 412 at all time. The rod 422 extends within a valve housing 424 through a suitable tubular structure 426 joined to the housing 424.

The housing 424 is similar to the valve housing previously described in connection with the previous embodiments and has disposed thereon a ball valve element designated by numeral 428.

The discharge side of the engine coolant pump 232 is tapped by means of a conduit 430 which delivers fluid to the interior of housing 424 at a point directly opposite the tubular structure 226. Another conduit 431 extends from the interior of housing 424 to the pressure responsive device 102 at one side of the partition 114. Another conduit 432 interconnects the space surrounding rod 422 with the device 102 at the other side of the partition 114. A bypass conduit 434 connects the conduit 432 with the intake side of pump 232.

ln the 'operation of-theembodimentof sFigure 'llgthe jprimary throttle lvalve is a'ctuatedink the usual manner by fmeans f* the' manually Vactuated linkage 4l-4,' -416 'and :418. V`"Whenthe throttle valve f410is in the' closed position, yas fshowninfFigure"ll, lthe cam-follower420 causes'the rod *422 to be depressedinto thehousing 'M4-thus preventing -theball '428 from rising to they upper portion ofthe interior of thetvalve andifromblocking oit/the opening into the tubular structure l426.

When the primary throttle valve `is'movedV to a predetermined setting,1therod '422 isrnove'd upwards a sutciently vgreat ldistance to permit the ball423to'block oli` the opening at the Yconnection* withfthe tubular structure 426.

'During 'operation' ofV the engine" below a; predetermined speed, theball will'assurn'e"the`position shownin Figure 'll `and the secondary throttle will-be .maintained closed `.throughout the operating range ofthe primary throttle 410 "byyir'tue ofltheforce'e'xerted'by spring 119 on shaft 116.

During operation of the engine above a predetermined speed and at 'a primary throttle opening in excess of a 'predeterminedsetting,thc ball 428'will be moved by the liquid coolant'passing through 'the valve housing 424 'thereby causing the passage throughthe tubular structure 'rod 422 will'be depressed bythe cam y412 thereby shifting therball 428 and opening-the tubular structure 426 and conduit 432 tothe highpressure discharge side ofpump i232. High pressure coolant-Will therefore be admitted to vboth working chambers of the device'102 vand the forces exerted-uponseach of the diaphragms 108 will oppose and cancel eac'h other. 'The spring 119 will thereupon be effective to close the Asecondary throttle valve v404. Thus, the secondary throttle may be opened only when rthe enginespeeds are above apredetermined Value and when the primary throttle valve issimultaneously opened to' a position above a predetermined setting.

Figure '12 shows another modification of the'invention which employs-a different type of quick action control valve. The Valve consists ofa housing v502 which includes two opposed .portions 504 and 5'06 which are joined' together at matingperipheral flanges 15.08. Aflexible diaphragm'SlO extends transversely across the interior "of the'housing and-is secured between the. peripheral flanges '508. The central 'portion of the diaphragm has secured thereto'apair'ofvalve elements512 and l514 which extend perpendicularly'to the plane of the diaphragm. A spring '516 is interposed'between Ithe housing portion '506 and thediaphragm `51'0 and urges the diaphragm axially in one direction.

A uid conduit 518 interconnects the'high pressure dischargeside of enginecoolant pump 232 yand a working chamberon one side ofthe diaphragm 1510. This cham- 'ber is designated in Figure l2 by the symbol X. Another conduit 520 extends from the working chamber on the other side ofthe diaphragm 510-to the low pressure intake side .of the pump 232. This second working chamber is designated by the symbol CY.

:Valve ports Uare providedat 522 4and 524 substantially in the center of

the'housingfportions

504 and 506, respectively, and are each connected to a common conduit v526.

YThe valve `elements`f512 andr514, carried by the diaphragm 510, extend into close proximity to the lports-522 and 524, respectively. The conduit 526 is connected at its extreme end to apressure responsive actuating device 528. A bypass conduit 527 interconnects ,the conduit 526 and the valve port 524 in the housing .portion 506.

The device ,'528 consists of apair of Yopposed .housing ,portions 4530 and S32 which dene aninter'ior-cavity within which a flexible diaphragm'534 is transversely disposed.

` Diaphragm 534 may be 'secured about lits periphery vbed tween the matingperipheral'tedges"fthefhousing portions Aprirnary throttle barrel isshown' at536L and atseoondary 'throttlebarrel is shown lat'538. Throttle'valves540 and542 arerotatably mounted withintheiprimary"and secondary vbarrels respectively. Primary Vthrottle valve 540 may be vactuated by"a"'manually'actuated throttle linkagein the usual manner. The secondary vthrottlevalve 542 is operatively connected' to the 'centerfon ldiapl'iravgn 534 by means of linkage elements 54'4`and546. Asp'rin'g 4548 may be interposed betweenthelhousing portion 532 and diaphragm S34 to bias the secondary'throttle valve into a normally closedposition. l

In the operation of the embodiment of 'Figurefll'engine coolant may be tapped from the kdiseha'rgedfuthe'pump 232 and conducted into'the working chamber 'Xthrough conduit S18. During operation of the engine "below a predetermined speed any'coolant which may'pass around L'the valve element 512into thejport`522will 13e-directed through theconduit527`backinto the port y5'2'4andthe'n into the intake side of the coolant'pump throughconduit '520. Upon an'increase in the'enginespeedbeyondthis predetermined limiting speed, the pressure diiferential across the coolant pump^232, which is vvalso appliedacross 'the diaphragm'5'10, will cause the diaphragm 510 to'l shift to theright, as viewed in vFigure '12, thus causing the port 524- to become restricted while simultaneously opening the port 522. This'shifting motionwill cause'a'pressure one side of the diaphragm "534 thuscausing th'esa'me'to in the engine speed to a value below thetpredeter'mined limit, the diierential pressure ac ross the diaphragm 510 will Ibe jinsuiiicient to maintain :the diaphragm '510 and the valve lelements l"51.2 and )ST4 in 'a'1 shifted position and Ithe spring 516 will be-eiective toreturn the valve elements to the'neutral position, yas shown in Figure 12.

Figure 13 shows a modified quick action control'valv'e 'which may be substituted lfor the valve of the embodiment of Figure 1'2. This modified valve comprises ahousing 692 which also has two opposed portions604 and '606 joined at mating peripheral ilanges608. A'exible diaphragm 610 extends across the interior'of lthe housing 602 and carries atits'center a pair vofiflatvalve elements '612 and '614. vThe lfluid conduits which provide communicationbe'tween the pump 232an`d la secondary throttle 'valve actuating device may be arranged in a manner similartothat ofFigur'e r12. 'The-

conduits

618 and 620 correspond in function to`conduits k'5138 and l5'20in Figure 12, respectively.

Valve ports are provided in theho'us'ing portions 1604 and vw'606 at6'22 and 624respectively. A spring'638 is interposed'between the diaphragm "61.0 and the housing 'portion A"6106 'and Iis effective 'to Vbias the diaphragm v`a'n'd one'fvalve element'coaxiallygagainst aninwardly directed extension 636 of the conduit'6246.

lA conduit 626 'is connected to the valve port 622 and vextendsto oneside 'of aexible diaphragm within apressure'responsive actuator, not specifically illustrated. The

other side of the liexible diaphragmof the pressurel responsive actuator is connected to thelow pressure conduit 620 yby meansl of conduit 634. A'Such a pressure actuatorma-y -include'afhousing andthe liexible diaphragm therein may divide the-interior'of thehous'ing into apair ofworking chambers, each of which are connected to conduits 626 or S34-respectively.

The other side of the exible diaphragm '610.m`ay 'be connected rto Conduit 6 2@ lby means Aof conduit 629. A bypass conduit is providedat y627 which interconnects 'conduit 626 `with port 624.

-In theoperationof the fmodiiied valveof :Figure 13, the pressure diierential `which exists across the pump -232 is impressed upon opposite `sides Vof 1 diaphragm 61'0 through the

conduits

618 and 620. During the operation of the engine below a predetermined limiting value, the position of the diaphragm 610 and the valve elements 612 and 614 are shown in Figure 13. Upon a subsequent increase in the engine speed, the coolant pump pressure becomes sufficiently great to deect the diaphragm 610 and its associated valve elements against the force exerted by spring 638 to close the valve port 624 while simultaneously opening port 622. The fluid pressure will thereupon increase in the conduit 626, and one side of the exible diaphragm in the pressure responsive actuator device. At the same time, the other side of the iiexible diaphragm in the actuator device is connected to the intake side of the engine coolant pump. The actuator device is therefore responsive to coolant pressure differential across the pump.

Upon being energized, the actuator device will open the secondary throttle valve to which it may be linked in the usual manner. Upon a subsequent decrease in pump pressure differential, the spring 638 will urge the valve element 612 against port 622 thus decreasing the pressure acting against the diaphragm of the actuator device.

In all of the preceding embodiments herein disclosed, the actuating device for the secondary stage is responsive only to the pressure differential across the engine coolant pump. Therefore the absolute value of the pump discharge pressure may be subject to variation without affecting the calibration of the carburetor control mechanism.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art, and the invention is to be given its broadest variation within the terms of the following claims.

l claim:

1. In a liquid coolant internal combustion engine having an intake manifold and a liquid coolant pump, at least two conduits for supplying a combustible mixture to said intake manifold, a throttle valve in each of said conduits, means for actuating one of said valves for controlling the passage of a portion of said combustible mixture to said manifold, other means for actuating a second valve in another of said conduits to supply an additional controlled charge of combustible mixture to said manifold during the operation of said engine within a predetermined speed range, said other means including portions mechanically controlled by said first named means, and means responsive to variation in engine coolant pump pressure for moving one of said controlled portions to an inoperative position when the engine coolant pressure exceeds a predetermined value during the operation of said engine within another predetermined range of engine speeds.

2. In a multiple stage carburetor for a liquid cooled internal combustion engine having an engine driven coolant pump, a plurality of induction passages, throttle valves in each ofsaid passages, means for controlling the operating position of said valves including a portion connected to one of said valves and another portion connected to another of said valves, said means further including a one way mechanical connection between said portions which provides for simultaneous movement of both of said valves during movement of said one valve within a predetermined range of operating positions, and means responsive to variations in engine coolant pump pressure for adjusting the relative position of said portions to render the same ineffective to control the position of said other valve at engine speeds below a predetermined limiting valve.

3. In a liquid cooled internal combustion engine having an engine coolant pump and an intake manifold, at least two conduits for supplying a combustible mixture to said intake manifold, a throttle valve in each of said conduits, means for actuating one of said valves for controlling the passage of a portion of said combustible mixture to said manifold, other means for actuating a second valve in another of said conduits to supply an additional controlled charge of combustible mixture to said manifold during the operation of said engine within a predetermined speed range, said other means including portions mechanically controlled by said rst named means, and means responsive to engine coolant pump pressure for moving said controlled portions to an inoperative position during the operation of said engine within another predetermined range of engine speeds.

4. In a liquid cooled internal combustion engine having an engine coolant pump and an intake manifold, at least two conduits for supplying a combustible mixture to said intake manifold, a throttle valve in each of said conduits, a tirst linkage element operatively connected to one of said valves, a second linkage element connected to the other of said throttle valves, means for moving said second linkage element into and out of an operative position in response to pressure differential across said engine coolant pump, said elements being adapted to engage each other upon movement of said one throttle valve beyond a predetermined setting when said second linkage element is in an operative position to actuate the other of said throttle valves and to control the supply of combustible mixture to said manifold.

5. In a multiple stage carburetor for a liquid cooled internal combustion engine having an engine driven coolant pump, a plurality of induction passages, throttle valves disposed within each of said passages, linkage means for actuating one of said valves, means for actuating the other of said valves having a portion thereof adapted for engagement with a portion of said linkage means during movement of the latter within a predetermined range of operating positions, and means for adjusting the relative positions of said portion of said second named means with respect to said linkage means in response to variations in coolant pressure differential across said pump.

6. ln a multiple stage carburetor for a liquid cooled internal combustion engine having an engine driven coolant pump, a plurality of induction passages, throttle valves in each of said passages, means for controlling the operating position of said valves including a portion connected to one of said valves and another portion connected to another of said valves, said means further including a one way mechanical connection between said portions which provides for simultaneous movement of both of said valves during movement of said one valve within a predetermined range of operating positions, and means responsive to pressure differential variations across said engine coolant pump for adjusting the relative position of said portions to render the same ineffective to control the position of said other valve at engine speeds below a predetermined limiting value.

7. In a multiple stage carburetor for use with a liquid cooled internal combustion engine, a primary induction passage, a secondary induction passage, primary and secondary valves mounted within said primary and secondary passages respectively, means for controlling the position of said primary throttle valve, a control element operatively xed to said secondary valves, a one way mechanical connection between said element and said control means for actuating the secondary valve during movement of said primary throttle valve within a predetermined range of operating positions, and means responsive to pressure variations between the discharge and intake sides of said engine coolant pump for rendering said secondary valve inoperative during operation of said engine within another predetermined range of engine speeds.

8. In a two stage carburetor for an internal combustion engine, a plurality of induction passages, a primary valve in one of said passages, a secondary valve in another of said passages, a first link element fixed to said primary valve and movable therewith during manual Voperation of said primary Valve, ai-se'cond link member 'fixed to saldsecondary valve, a third llink member piv- .otally-:connected fnear one end thereof to said second member andoperatively connected to a movable fulcrum lmember at -a `,central portion thereof, said rst Vmember-bemg adapted-toengage and actuate said second-'member nearithe other end thereof during movementof the .primary vthrottle through a predetermined frange of engine speeds, .and-meansresponsive to `engine speed-'for adjusting the-positionV of said 'fulcrum member torender-the secondary valve inoperative during operation of the eng-ine-wvithin another-predetermined range lof engine speeds.

`9. Atwo stage carburetor as set forth in claim 8 wherein said engine is vliquid cooled and wherein said 'engine speed 'responsive means includes an actuator device having almovable-actuator shaft, conduit means for =conducting engine coolantto said device thereby providing an enginespeed signalfor energizing the same, `and linkage means connecting said fulcrum member to said lactuator shaft.

10. In a two stage carburetor for a liquid cooled internal combustionY engine having an engine driven coolant pump,-a pluralityof induction passages, throttle valves -disposed within each `of said passages, linkage means -for manually actuating oneI throttle valve in one of said passages, a one Way mechanicalA connection between said fone throttle=valve and another'throttle valve in another :of said passages for actuating said other throttle valve :throughout a predetermined range of operating posi- .j ytions for said one Ythrottle valve, said connection including'cooperating'linkage elements connected to said primary and secondary valvesfrespectively, and means vresponsive to engine coolant pump pressure differential -across said coolant pump for shifting-one of said linkage elements -to a relatively remote position with respect to said other linkage element to render said connection inoperative atfengine speedsbelow a predetermined limiting value.

'11. In aftwo stage carburetor'for a liquid cooled internal combustion engine having an engine driven coolant pump, aplurality of induction passages, throttlefvalves disposed yWithin each of said passages, linkage means for manually actuating one throttle valve in one of said passages, a one way mechanical connection between said ione-throttle valve and another throttle valve in another of said passagesfor actuating said other throttle valve throughout a predetermined range of operating positions for said one throttle valve, said connection including cooperating'linkage elements connected to said primary and secondary vvalves respectively, means re- `-sponsive to Iengine coolant pump pressure differential `across said coolant pump -for shiftingone ofsaid linkage lelements'to a relatively remote position with respect to ysaid other linkage element to render said connection -inoperative at engine speeds below a predetermined limiting value, said pressure responsive means including an actuator device, a movable actuator shaft voperatively carried by said device, a mechanical connection between said actuatorshaft and said one linkage element to shift formanually actuating one throttle valve in one of said passages, a one way mechanical connection between said one throttle valve and another throttle valve in another of said 'passages for actuating said other throttle valve throughout a predetermined range of operating positions for said one throttle valve, said connection including cooperating linkage elements connected to said primary and secondary valves respectively, means responsive to engine coolant pump lpressure differential -Iacross-'said `coolant-*pump 'for f'shifting one of said `linkage nelements to Ia 'relatively remoteposition wit-hrespect'to y.said other'linkage element to render said -connect-ion inoperative at engine-speeds`=be1ow la predeterminedflimit- -ing value,wsaidpressure responsive meansfincluding'an actuator device, fa =movable `actuator shaft -operatively carried by-said1fdevice, 4Aal'mechanical connection between y"saidfactuatorshaft and said` one" linkage element to `shift the"1same, `and conduit structurerinterconnecting-said.devicelfwith said coolant pump, said conduit-structureI--in- Icluding a quick-action control rvalve' interposedltherein Iforcontrolling 'thev transfer of' engine 'coolant 'pump pres- -sure to said'device.

il3. tIinf--a-'multiple stage carburetorfor use with yliquid cooled "internal Acombustion engines 'having an intake ymanifold and an engine 'driven' coolant pump, af plurality of passages for supplying a 4combustible mixture to said manifold, 'afprimarythrottle valve in-one of Yfsaid passages, a-"secondary throttle valvei'in another'of saidpassages, means =for vrmanually controlling said 'primary throttle valve, a mechanical 'lost motion fconnectionbetween saidfvalves zincludinglinkage portions having -a'lost `motion Vgap' therebetween;v af pressure responsive actuating -device,an lactuator ro'd 'forming a port-ion of said device `and connected to another portion of said lost motion `connection, landconduitmeans for connecting said "device to saidenginecoolantpump -to provide said device with coolant pump pressure, said actuator 'device being adapted fto move said other portion-upon 'being energized vwith engine coolant pressure thereby reducing the magnitude of saidf-losttmotion gap.

114. A multiple stage carburetor as setforth in 'claim 113 wherein saidactuatorfdevicety includes a housing and -a pair of opposed Working chambers in said housing, and whereinsaid conduitmeans'includesa `fluid control valve housing, -a sphericalv-lve element disposed Within lsaid 'housin'g,-a pair of valve portsin said housing and-axially a'ligne'dw'ith respect thereto, a third valve port located intermediate said pair, a'rst conduit interconnecting one of' saidpair ofzportsfwiththe 'discharge side of said-pump, a-second conduit connecting the other-of said pair of tportslwith the-intake side of said pump, a third conduit connectingsa-id'second conduit to one of saidpairs of -workingfchambers, and 'a fourth conduit connecting said intermediate valve port to ythe other of said lworking chambers, said spherical Valve element being adapted to block-the other of said pair of vvalve ports vwhen a pre- .determined vpressure diiferential is reached across said 'pump fthereby'fcausing an actuating pressure differential to build-up in said working `c'zharribers to shift ysaid actuatorfrod.

115. Inla multiple stage carburetor for usewith a liquid cooled-internal combustion engine having an intake manifold and an engine driven coolant pump,a"pluralityof -passages Yfor *supplying 'a lcombustible mixture to said manifold, a first-throttle valvein one of said passages, a 4second 'throttle valve in another of said passages, la 'linkage for manually actuating said rst throttle valve, an engine coolant pressure responsive device including a movable actuating member, conduit means for supplying engine coolant pump pressure to said device to actuate -the same, a lost motion element fixed to said second throttle valve, another cooperatinglost motion element rotatably mounted upon a portion of said second throttle valve, a rst link element operatively-connected to said actuator shaft at one 'end thereof, `said first throttle being mechanically connected' to vthe other end of said link element, and another linkconnection between the intermediate portion of said rst link element and said other lost motion element.

`16. lIn"combinationwith a multiple stage carburetor for a liquid cooled internal combustion engine having an engine coolant pump, at least one pair of induction passages, a primary throttle valve in one of said passages, a secondary throttle `valve in anotherof said passages;

a pressure responsive actuator device having a movable portion thereof operatively connected to said secondary throttle to actuate the same, a pair of opposed working chambers within said actuator device, fluid conduit structure for delivering coolant pressure from said pump to said working chamber, a quick action control valve interposed in said conduit structure for causing said actuator device to be energized when the coolant pressure exceeds a predetermined minimum value, and means for rendering said control valve inoperative when the primary throttle is operated within a predetermined range of positions.

17. The combination as set forth in claim 16 wherein said control valve comprises a housing, a spherical valve element adjustably disposed within said housing, a pair of opposed valve ports in said housing on diametrically opposite sides of said valve element, an intermediate valve port in said housing, a rst conduit connecting one of said pair of ports to the discharge side of said pump, a second conduit connecting the other of said pair of ports to one of said working chambers, a third conduit connecting said intermediate port with the other of said working chambers, a bypass conduit connecting said second conduit to the intake side of said pump, and wherein said means for rendering said control valve inoperative includes a rod slidably disposed within said housing and adapted to control the movement of said valve element, and means for moving said rod into contact with said valve element in response to movement of said primary throttle valve, said rod thereby preventing movement of said valve element.

18. In combination with a multiple stage carburetor for use with a liquid cooled internal combustion engine, at least two induction passages, a primary throttle in one of said passages, a secondary throttle valve in another of said passages, a pressure responsive actuator device having a movable actuator shaft thereof operatively connected to said secondary throttle valve, said actuator device including at least one movable wall element partly defining opposed working chambers, said actuator shaft being connected to said movable element, a quick action e control valve, said control valve including a flexible diaphragm partly defining opposed pressure chambers on either side thereof, conduit means for connecting said pressure chambers to the intake and discharge sides of said pump, metering ports disposed on opposite sides of said diaphragm, other conduit means for connecting said ports to one of said working chamber, and movable valve elements carried by said flexible diaphragm for selectively restricting said ports in response to pressure differential variations across said pump.

19. The combination as set forth in claim 18 wherein said movable valve elements comprise projections extending at least partially through said ports for variably restricting the same.

20. The combination as set forth in claim 18 wherein said movable valve elements comprise flat valve discs adapted to selectively cover said ports to restrict the same.

2l. A two stage carburetor for use with a liquid cooled internal combustion engine having a coolant pump and an intake manifold, at least two conduits for supplying a combustible mixture to said intake manifold, a throttle valve in each of said conduits, linkage means for actuating one of said throttle valves, and means for actuating another of said throttle valves in response to coolant pressure differential across said coolant pump.

22. In a multiple stage carburetor for a liquid cooled internal combustion engine having an intake manifold and an engine coolant pump, at least one pair of induction passages for supplying a combustible mixture to said manifold, throttle valves in each of said passages, linkage means for actuating a first of said throttle valves, a one way mechanical connection between said valves providing for simultaneous movement of said first and a second of said throttle valves during movement of said first throttle valve over a predetermined range of positions near the wide open throttle setting, a pressure responsive actuator device having a pair of opposed working chambers therein, a movable actuator shaft operatively connected to said device, a portion of said one way connection being connected to said actuator shaft, conduit means for connecting said working chambers to either side of said coolant pump, and valve means for regulating the distribution of coolant pump pressure through said conduit means so as to selectively apply coolant pump discharge pressure to either one or both of said working chambers as determined by the magnitude of the engine speed.

23. A two stage carburetor for use with a liquid cooled internal combustion engine having a coolant pump and an intake manifold, at least two conduits for supplying a combustible mixture to said intake manifold, a throttle valve in each of said conduits, linkage means for actuating one of said throttle valves, and means for actuating another of said throttle valves in response to coolant pressure differential across said pump, said last named means including a pressure responsive actuating device, a fluid passage interconnecting said device with each side of said coolant pump, and a quick action flow control valve interposed in said passage for regulating the distribution of engine coolant pressure in said passage whereby said coolant pressure may be applied to said device to actuate the same only at engine speeds above a predetermined limiting value.

24. A two stage carburetor as set forth in claim 23 wherein said quick action control valve includes a valve housing, a flexible diaphragm within said housing, valve ports in the wall of said housing on either side of said diaphragm, and valve elements carried by said housing for restricting said ports, said passage including portions connecting opposite sides of said diaphragm to respectively opposite sides of said pump and other portions connecting at least one of said ports to said actuating device.

25. A two stage carburetor as set forth in claim 23 wherein said quick action control valve includes a hollow valve housing, a plurality of valve ports in said housing, and a spherical valve element disposed within said housing between two of said ports for alternately restricting the same, said passage including portions connecting certain of said ports to respectively opposite sides of said pump and other portions connecting at least one other port to said actuator device.

26. A two stage carburetor as set forth in claim 23 wherein said linkage means include portions comprising a lost motion mechanical connection between said throttle valves.

27. A multiple stage carburetor for a liquid cooled internal combustion engine having an engine driven coolant pump and an intake manifold, said carburetor cornprising a primary throttle stage and at least one auxiliary throttle stage, said stages each including means for supplying a combustible mixture to said engine manifold, and means for controlling the operation of said auxiliary stage in response to coolant pressure differential across said pump.

28. In an internal combustion engine having an intake manifold, a primary mixture conduit and a secondary mixture conduit for supplying said manifold with a combustible mixture of fuel and air, a primary throttle valve mounted in said primary conduit and a secondary throttle valve mounted in said secondary conduit, linkage means interconnecting said primary and secondary throttle valves, said linkage means including a first linkage element joined to and movable with said primary throttle valve, a second linkage element joined to and movable with said secondary throttle valve, a third linkage element joined at one end thereof to said second linkage element, means for pivoting said third linkage element about a point thereon intermediate its ends, and engine speed responsive means for shifting said pivoting means to either of two operating positions, said first linkage element being adapted to contact and rotate said third Alinkage element about said intermediate point when said pivoting .means assumes one of said operating positions as the primary valve is moved within a predetermined .range `of throttle settings near the wide open'position thereby opening said secondary throttle valve, said 'secondary throttle valve remaining in a closed lposition dui'- ing movement of said lprimary throttle valve when said pivoting lmeans assumes the other of said operating positions.

2'9. The combination as set forth in claim 28 wherein said engine speed responsive means comprises a pressure responsive actuator having portions operatively connected to said linkage means, said engine being provided with an engine driven engine coolant pump, and conduit means providing -communication between said pump and said pressure responsive actuator, 'said pressure responsive actuator being energized by engine coolant pressure when the engine speed exceeds a predetermined maximum value.

30. In an internal combustion engine having an intake manifold, a primary mixture conduit and a secondary mixture conduit for supplying said manifold with a combustible mixture of fuel and air, a primary throttle valve mounted in said primary conduit and a secondary throttle valve mounted in said secondary conduit, linkage means interconnecting said primary and secondary throttle valves, said linkage means including a first linkage element joined to and movable with said primary valve, a second linkage element joined to and movable with said secondary valve, an engine responsive actuator including a movable actuator shaft, a third linkage element pivoted at one end thereof to said actuator shaft, an intermediate portion of said third linkage element being joined to said rst linkage element, said actuator shaft being adapted to assume either of two operative positions, the other end of said third linkage element being adapted to contact and to rotate said second linkage element and to open said secondary throttle valve when said actuator shaft assumes one operating position as the primary throttle valve is moved within a predetermined range of operating positions near the wide open setting.

3l. The combination as set forth in claim 30, wherein said engine includes an engine driven coolant pump and wherein said actuator includes a pressure responsive servo mechanism, and conduit structure providing communica` tion between said engine coolant pump and said servo mechanism, said servo mechanism being energized upon an increase in engine conduit pump pressure beyond a predetermined value thereby shifting said actuator rod to said one operating position.

32. In an internal combustion engine having an intake manifold, a primary mixture conduit and a secondary mixture conduit for supplying said manifold with a combustible mixture of fuel and air, a primary throttle valve mounted in said primary conduit and a secondary throttle valve mounted in said secondary conduit, linkage means interconnecting said primary and secondary throttle valves, said linkage means including a first linkage element joined to and movable with said primary valve, a second linkage element joined to and movable with said secondary throttle valve, an engine speed responsive actuator including a movable actuator shaft, a third linkage element pivoted at one end thereof to said actuator shaft, a fourth linkage element pivoted at one end thereof adjacent said second linkage element, the other end of said fourth linkage element being joined to said third linkage element intermediate the ends thereof, the other end of said third linkage element being joined to said rst linkage element, said second and said fourth linkage element forming a one-way connection, said actuator shaft being adapted to assume either of two operative positions and to shift said fourth linkage element into and out of a position closely adjacent said second linkage element, the secondary throttle valve being opened as the primary throttle valve is moved to a range of posi- 18 tions greater than the wide 4open setting, said fourth linkage element being adapted to contact said second linkage and to open said secondary throttle valve when it assumes said position adjacent said second linkage element.

33. The combination as set forth in claim 32 wherein saidy engine includes an engine driven coolant pump and wherein said 'actuator includes -a pressure responsive servo mechanism, and conduit structure providing communication between said` engine coolant pump and -said servo mechanism, said servo mechanism being energized upon an increase in engine coolant pump pressure beyond a predetermined value thereby shifting said actuator shaft to one of said operating positions and shifting said fourth linkage element into said position adjacena said second linkage element.

34. In a liquid cooled internal combustion engine having an intake manifold and` an engine driven coolant pump, iirst and second mixture conduits for supplying said manifold with a controlled combustible charge, a primary throttle valve in the iirst of said conduits, a secondary throttle valve in the second of said conduits, linkage means for actuating the first of said valves, pressure responsive means for actuating said secondary throttle valve comprising diaphragm structure and an actuator linkage means interconnectingv said diaphragm structure and said secondary throttle valve, said diaphragm structure defining in part two opposed working chambers, conduit structure interconnecting said coolant pump with at least one working chamber of said pressure responsive means, and valve means for controlling the distribution of coolant pressure to said pressure responsive means, said valve means including a flexible valve diaphragm defining two opposed valve chambers, one of said valve chambers being connected to the high pressure side of said coolant pump and the other of said valve chambers being connected to the low pressure side of said coolant pump, said one valve chamber communicating with one of said working chambers, passage means for bypassing fluid from said one valve chamber to said other valvechamber, and a valve element carried by said valve diaphragm for restricting said bypass means upon deflection of said valve diaphragm as the coolant pump pressure differential increases beyond a predetermined value thereby causing a rapid pressure buildup in said one pressure chamber.

35. The combination as set forth in claim 34 wherein said valve diaphragm carries another valve element, said other valve element being adapted to control the degree of communication of said Working chamber with said one valve chamber, the degree of communication increasing upon deflection of said valve diaphragm under the inuence of engine coolant pressure differential.

36. In a liquid coolant internal combustion engine having an intake manifold and an engine driven coolant pump, irst and second mixture conduits for supplying said manifold with a controlled combustible charge, a primary throttle valve in the rst of said conduits, a secondary throttle valve in the second of said conduits, linkage means for actuating the first of said throttle valves, pressure responsive means for actuating said secondary throttle valve comprising diaphragm structure and an actuator linkage means interconnecting said diaphragm structure and said secondary throttle valve, said diaphragm structure defining in part two opposed working chambers, conduit structure interconnecting said coolant pump with at least one working chamber of said pressure responsive means, valve means for controlling the distribution of coolant pressure to said pressure responsive means, said valve means comprising a valve chamber, said conduit structure including separate portions respectively connecting said valve chamber with the high pressure side and the low pressure side of said coolant pump, said conduit structure including another portion connecting said valve chamber with one of said working chambers, a spherical valve element disposed in said valve chamber,

and a bypass passage means communicating with said valve chamber for conducting fluid from the high pressure side to the low pressure side of said pump, said valve means being adapted to restrict said bypass passage means upon an increase in the pressure differential across said conduit pump beyond a predetermined value thereby causing a rapid pressure buildup to occur in said one working chamber.

37. The combination as set forth in claim 36 wherein the linkage means for said primary throttle valve includes portions for restricting the movement of said spherical valve element upon movement of said primary throttle valve throughout a range of positions less than a predetermined setting thereby preventing a pressure buildup from occurring in said one working chamber While said throttle position is in said predetermined range.

38. In a liquid cooled internal combustion engine hav- References Cited in the file of this patent UNITED STATES PATENTS 2,282,311 Ericson et al May 12, 1942 2,376,732 Strebinger May 22, 1945 2,640,472 Bicknell June 2, 1953