US2943848A - Separate thermostat controlled fast idle cam - Google Patents

Description

' y 5, 1960 n. M. GORDON ETAL 2,943,848

SEPARATE THERMOSTAT CONTROLLED FAST IDLE CAM 0 GDP 4 11) i o t GD 4 (1]) a Q 1 u. 0

,5.\ Q) GD 2' I f INVENTORS m (6 l QWENFORDIEHIGHLEY V15 4 SBYDWIGHT M. GORDON M X W ATTORNEY July 5, 1960 D. M. GORDON ET AL 2,943,843

SEPARATE THERMOSTAT CONTROLLED FAST IDLE CAM Filed Oct. 6, 1958 3 Sheets-Sheet 2 a 0 INVENTORS O I/ O WENFORD E.H|GHLEY BY DWIGHT M.GORDON ATTORNEY July 1960 D. M. GORDON ETAL 2,943,848

SEPARATE THERMOSTAT CONTROLLED FAST IDLE CAM Filed Oct. 6. 1958 3 Sheets-Sheet 3 14 21 INVENTORS 35 WENFORD E. HIGHLEY 37 97 BY DWIGHT M. GORDON ATTORNEY United States ate SEPARATE'IHERMOSTAT CONTROLLED FAST IDLE CAlVi Dwight M. Gordn,Farmington, Mich, and Wenford n.

HIghIey, Normandy, Mo., assignors to ACE Industries, gncorporated, New York, N.Y., a corporation of New ersey Filed Oct. 6, 1953, Ser. No. 765,387

20 Claims. (Cl. 261-49) Thisinvention relates to carburetors for internal combustion engines, especially of the automotive type, and more particularly to means for controlling the position of the throttle valve of the carburetor at idle'in such manner as to insure satisfactory engine idle speed in cold weather when the temperature under the hood of the automotive vehicle may be low. a

It will be understood that certain carburetors of the class described have a fast idle cam controlled by the choke valve of the carburetor (the choke valve, in turn, being controlled in response to engine temperature and suction in the intake manifold of the engine) for controlling the position of the throttle valve at idle. The fast idle cam is formed so that, when in a starting position with the engine cold and the choke valve closed, it blocks the throttle valve partly open and, as the engine warms up and the choke valve opens, it blocks the throttle valve open to a lesser degree to provide the correct idle speed. For this purpose, the cam is usually engageable by a screw on the usual throttle operating arm. When the choke valve reaches full open position, the cam may-assume a full off or inactive position, to permit the throttle valve fully to close or to close to a preset position, as may be determined either by engagement of the screw with the cam, or by engagement of a lugon the throttle operating arm and the cam due to the force exerted by the usual' throttle return spring restrains cam movement until the throttle is opened manually to disengage the screw from the cam and allow the cam to move progressively toward an inactive position. This can occur continuouslyor on each throttle opening as the engine approaches normal operating temperature. In cold weather, when the temperature under the hood of the vehicle is low prior to complete engine Warm-up, and consequently the temperature of the air flowing to thecarburetor is low, it has been found desirable to maintain the throttle valve blocked open at idle to provide the correct idle speed, even though the choke valve may be open, until the temperature under the hood is increased by heatfrom the engine.

The main object of the invention is to provide art-engine idle speed control which is responsive to more thansimply one temperature variable, such as occurs during the action of the choke thermostat in the choke control mechanism as above described.

Another object of the invention is to provide a fast idle device with a temperature control responsive to the temperature of the air flowing to the carburetor, which device operates each time the throttle is closed from an open position to effect a change in the rate of-flow of the idle mixture so as to establish an idling engine speed which is stable in spite of mixture temperature fluctuations.

In one form of this invention these objects are accomplished by providing a thermostat controlled means pri marily responsive. to air temperature and acting as a limiting means on the movement of the fast idle cam toward inactive or oil position. In this form, 7 this thermostat control. of the .fastidle cam is superimposed onthesusua control forthe fast idle cam from the-automatic choke mechanism, and isso arranged as to be inefiective and inactive when the throttle is opened so as not to interfere with any other function of any other control-mechanism on the carburetor. In other words, it becomes eifective' only when the throttle is closed, and utilizes this operation to move the cam into an active position, depending upon temperature of the air flowing to the carburetor. This active position, in turn, determines the degree of throttle closing. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the. constructions hereinafter described, the scope of the invention being indicated in the following claims. v

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

Fig. 1 is aplan View of a four-barrel-carburetor in which the invention is incorporated;

Fig. 2 is a view in'elevation of the left end of Fig. 1, showing the fast idle cam of the carburetor in starting position, and showing in solid lines the position of the thermostatic means ofthis invention at normal temperatures and in dotted lines the position thereof at relatively low temperatures;

Fig. 3 is a view similar to Fig. 2, showing the fast idle cam in an advanced position;

Fig. 4 is a view in elevation of the right end of Fig. 1, with parts broken away and shown in section;

Fig. 5 is fragmentary side elevation; and,

Fig. 6 is a view similarto Fig. 2 illustrating "amodification.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to the drawings, the invention is'illustrated in its application to a 'multi-barrel, multi-stage carbure tor 1 of the type commonly referredto as a four-barrel Only so much of the construction of .the

' Gordon, Serial No. 752,979, filed August 4, 1958,:for

example, for such further details as maybe :desired.

In general, the carburetor 1 comprisesa-fuel bowl section '3 having lugs such as indicatedat 5 by which it may be attached to the intake manifold of theengine on which it is used. Mounted on the fuel bowl section-3is the usual air horn section 7. The fuel bowl section 3 is formed to provide two primary mixture conduits or barrels each designated 9 and two secondary mixture conduits or barrels each designated 11. The air horn section 7 is formed with a-partition 13 dividing it to form a primary inlet 15 and a secondary inlet 17.

A choke valve 19 (shown open in Figs. 1 and 3, closed in Figs. 2 and 4) is provided in the primary inlet 15 for controlling the admission of air to the primary barrels. The choke valve is fixed on a choke shaft 21 which extends across the inlet 15. A choke mechanism housing is indicated at 23. This contains-the usual suction and temperature-responsive mechanism such as shown, for example, in the (Coffey US. Patent 2,325,732. The choke mechanism is connected in theusual manner as indicated at 25 in Fig. 4 to one end of the choke-shaft 21, the arrangement being such that the usual choke thermostat 27 in housing 23 tends to hold the choke valve closed and, upon being heated, allows the choke valve to be-opened by the usual suction-responsive chokeaotuating piston 29. In this respect, it will be understood that the choke thermostat is heated'by airv supplied to the housing 23as from a heat pocket in the exhaust manifold of the engine. f 1

' l '"by the screw.

3 At 3 1 is indicated the prim carburetor. This carries the "usual pair offprirnary throttlevalves, one for each of theitwoprimary barrels," indicated at 33 in Figs. .Zand 3. ,Fix'ed ontheend of ary throttle shaft of the I V the primarythrottle shaft131 at the side of the ca'rburetolfloppo site the .cholieimechanism housing'l23 is'the pn'mary throttle arm 3511f the carburetorgl; .It .will

bexunderstood'thatfconnection ismadeto arn1,35 from the usual acceleratoripedal of the vehicle, springmeans :with a series'of steps such. as indicated at'i45 'for engage- 'ment by screw 37 and is rotatable'on pivot 43 through a range of positions for bringing the difierent steps into opposition tothescrew; The series of steps includes a .so-c all ed starting step 47 which is the highest step (i.e., it is on the greatest radius from the axis of pivot 43); and

a finalstep 49 which constitutes the so-called normal .idle step and which is the lowest of the steps. Engagement of screw 37 with'the starting step 47 ;(see Fig. 2)

determines a maximum open idling position of the pri-* mary throttle valves 33. Engagement of screw'37 with the normal idle step v49 (see Fig. 3') determines a mini- 3 mum open idling position of the primary throttle ,valves 33; j

A fast idle'cam control arm 51 is mounted on the end of the choke valve shaft 21 forrotation relative to the "choke valve shaft; A-link '53 connects arm '51 and the fast idle cam. Ann 51 has a finger 55 engageable with P a tang 57r on an arm'59 fixed on the end of the choke valve shaft. The fast idle cam is overbalanced and hence gravity-biased to tendto swingclockwise as viewed in Fig 2; When the choke valve opens, arm 59 rotates.

7 counterclockwise asiviewed in Fig. 2. This permits the' -Pjfastv idleYcam to" swing clockwise under its gravity bias, 1 -.arm 51' rotating counterclockwise and following the arm 59 j'aroundf whenever the primary-throttle arm is moved in openingfldirection "thereby disengaging the screwl 37 from the pai The degree of rotation of the camfis dependientnpon-the degree of rotation of, the choke valve shaft 21 and arms 59 and 51.: The arrangement isfsuch that when the choke valve is closed (Fig. 2)

a 'th'e starting step 47 of thecarn-is positioned for engagernent'by screw 37 on the'primary throttle'arm 35, and when the choke valve is fully open (Fig. 3),"the normal idle step 49 is adapted to'be positioned for engagement 1 "At 61'isindicated the secondary ,throttleshaft'of the 5 'carburetor. This carries the usual pair of secondary throttle valves, one foreach of the two secondary barrels, indica'ted at 63 in Figs. 2 and 3; As herein illus- 'i trated," the secondary throttlevalves are adapted to be 7 ,opened inresponse to opening of the primary throttle '60 valves by mechanism such as indicated at 65 in Figs. 1

; and 4. This mechanism includes a lever 67 mounted on the other end of -the primary throttle shaft 31" ham the fprimary throttle arm 35 [and rotatable relative to -the primary throttle shaft Fixed to the pri-.

mary throttle shaft 31 outward of lever 67 is a lever; 69.

i Rotaryf'on the primary throttle shaft between levers 67 V I and 69 is an arm 171 having a finger 73 engageabler 3 behindia finger:75,on lever 69'and'having a finger 77 v Jengageable behind 'a U-shaped portion 79 of lever'67. 7O

twljich'receives the shaft 31 A'torsio'n spring 81 sur- {rounding shaft .31 inthefU-shaped portion 79 of lever] 67 has its ends hooked to fingers and 77 to tend to I 1 v hold fingers 73.and 75 in'engagement. A link 83 connectsf-lever 67 and a lever-85 fixed 'on'ftheend of the 75 secondary-throttle shaft 61. The latter is biased. in

, secondary throttle closing direction -(counterclockwis'eas viewed in Fig. 4) by a torg sion spring.87. (see Fig.-- l)., v j Lever 85 has a finger 8 9 en gageablewitha stop 91- formed on fuel bowl-section 3 to limit themoveme'nt of; t-hesecondary throttle valves in'op'ening directiontclocki- V T Wise vi wed aFisIti; Lawn- 5 a so hasap 93 engageable with anarm95 on -leven69-to prevent opening of the secondary-throttle valves until the primary J Y throttle valves have been partially opened (for example, 1 opened half-way) and arm 95 is moved clear of the pad. When the primary throttle valves are closed, finger I 77 is spaced from portion 79 0f lever 67 (seeiFigL4). As the primarythrottles are opened, finger 77 moves around and engages portion'79 of lever 67 when the primary throttles are partway opened .(halt way open, for example), and as theopeningof the primary throttle valves is completed, finger 71 drives lever167counter- 'clockwise' to pull'the'linl; 83 3down and swing t .85 to: open the secondary throttle valves. 7 V V W At 97 in Figs. 2, 3 and s is indicateda latch for 10;

:ing the secondary throttle valves against openinguntil the chokeivalve is fully open; This 'latch97 fis'pivoted on pivot 43' along the'fast idlelcam 41; It lla'sa' notch 99 in which is -engageable a lug 101 extending from a member 103 fixedon the end of the secondary V throttle shaft 61 adjacent the fast idle cam. The'latch}: 97 is gravity biased to swing counterclockwise as viewed 7 in'Figs. 2 and 3 to latching position in which lug 1101 is caught in thenotch 99 (see Fig. 2) to prevent movement in opening direction (counterclockwise as viewed in Fig. 2) of the secondary throttle shaft 61; The fast rdlecam has a finger 105 engageable with the latch 97 tojswing -it clockwise and downward away from its-latching posttion of 'Fig. 2 to release lug 101when the r'astidlecam swings from its Fig. 2 to itsE-ig. 3 position;- F ngeris also engageable upon return of'the fast idle cam with a lug 107 formed on the latch member 97 to swing the latter back to; latching position; V V In accordancewith'this invention, t

'a thermostatic element l llcarried by the primary throttle arm 35. Element 111 isconstitpted by abimetalhc blade starting position and screw 37 on arm 35-is in engagement with the starting step 147 on the cam, the blade is spaced below 'andclear of the finger 199-to?allow:the

fast idle cam to rotate clockwise'as viewedin Fig; 2 a

without restriction away from starting position. If the ambient air temperature should be relatively low, new ever, as in cold weathegblade' 111 bends up as illustrated in dotted lines in Fig. 2 into engagement with finger 109 to hold the fast idle cam against rOtating-cI ck-Q V .wiseVaway-from' its starting position. As' the underhood temperature rises due to engine heat, bladelll bends tion to ,a degree of the blade. V V I F Operation is as follows:

' Assuming that the weather is r dicated in solid lines 'inFig 2; clear; of the finger-i 109 'ion the-fast idle cam. After the engine has been started he lever he fast idle 441' f a is formed with a finger '109 'a daptedpfor engagement by elatively warmso that V i V it is relatively fwarm under; the hoodof the vehiclekthe therfiidstaticblade lil willo'cc'upy a pp'sitionlsuch as in (which is loose on the choke shaft).

mast-a Under these circumstances-the bladelil does not interfefe with the normal choke-controlled action of the cam. Now, assuming that thejweather is cold so that it is cold under the hood of the vehicle, the thermostatic blade 111 will occupy a position such as indicated in dotted lines in Fig. 2 beating up against the finger 109 on the fast idle cam. After the engine has been started, and as it warms up, the automatic choke mechanism will open up the choke valve 19 as before. However, under these circumstances, blade 111, as long as it is cold, holds up the fast idle cam and prevents it from advancing. Thus, the starting step 47 of the cam remains in opposi tion to screw 37 to keep the primary throttle blocked open a maximum degree to provide the correct idle speed, even though the choke valve is open. It be observed that the choke valve can open while the fast idle cam remains in starting position, due to the provision in the connection between the choke valve and the cam for the lost-motion between arm 55 and finger 57; Thus, opening of the choke valve without movement of the cam is permitted by reason of the fact that arm 59 (which is fast on the choke shaft) can rotate away from arm 57 Ultimately, the underhood temperature rises due to engine heat, and blade 111 bends back to a condition such as indicated in solid lines in Figs. 2 and 3, in which it is clear of the finger 1G9 on the fast idle cam to permit the latter to swing all the way to its normal idle position of Fig. 3 for bringing the normal idle step 49 into opposition with the screw 37, also for releasing the secondary throttle latch 97,

It will also be observed that with the blade 111 'mounted on the primary throttle arm 35, even if the underhood temperature is low and the blade is bent into the condition shown in dotted lines in Fig. 1, opening of the primary throttles (by swinging arm 35 clockwise from its Fig. 2 position) results in swinging of the blade 111 clear of the finger 169 on the fast idle cam. Ac-

cordingly, it is then possible for the cam to'swing counterclockwise from its starting position of Fig. 2 to a position such as shown in Fig. 3 to release the secondary throttle latch 97. Thus, the arrangement is such that there is no interference with the function of the fast idle cam to actuate the secondary throttle lockout.

Fig. 6 illustrates a modification which may be used where there is no problem of interference with a secondary throttle lockout, or if interference with the lockout is disregarded for the period required to bring up the underhood temperature in cold weather. The Fig. 6 modification is much the same as that of Figs. 1-5 eX- cept that the thermostatic blade, designated 121 in Fig. 6, instead of being mounted on the primary throttle arm, has one end fixed as indicated at 123 to a lug 125 on the fuel bowl section 3 of the carburetor. The other end of the blade reaches under the finger 169 on the fast idle cam 41. At relatively high ambient temperature, blade 121 is curved as illustrated in solid lines in Fig. 6 and projects in such direction as 'to allow the fast idle cam to swing to its normal idle position. However, if the temperature ambient to the carburetor islow, the blade 121 bends up as shown in dotted lines in Fig. 6 and holds the cam in starting position.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing trom the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shallbe interpreted as illustrative and not in'a limiting' sense.

We claim: 1. In a carburetor for an internal combustion engine,

said carburetor having a mixture conduit,- a choke valve and a throttle valve in said conduit, and means connected i M Q to the {choke valve forlimitingflcloslng of the throttle valve at idle in accordance with engine temperature, thermostatic means responsive to temperature. ambient to the carburetor for restricting the range ofjactive positions of said position controlling means at relatively low ambient temperatures independently of engine temperature and adaptedupon increase of ambient temperature to release said position controlling means. i

2. In a carburetor for an internal combustion engine, said carburetor having a mixture conduit, a choke valve and a throttle valve in said conduit, a fast idle cam connected to the choke valve for limiting closing of the throttle valve at idle, and means responsive to engine temperature for controlling the position of said cam, thermostatic means responsive to temperature ambient to the carburetor for restricting the movement of said cam at relatively low ambient temperatures independently of engine temperature. and adapted upon increase of ambient temperature to release said 'cam for response to engine temperature.

3 Ina carburetor for an internal combustion engine, said carburetor having a throttle valve, a choke valve, and means controlled by the choke valve for limiting closing of the throttle valve at idle, thermostatic means responsive to temperature ambient to the carburetor for restricting the range of active positions of said positioncontrolling means at relatively low ambient temperatin'es independently of the choke valve and adapted upon increase of ambient temperature to release said positioncontrolling means forcontrol by said choke valve.

4. In a carburetor for an internal combustion engine, said carburetor having a throttle valve, a choke valve, and a fast idle cam controlled by the choke valve for limiting closing of the throttle valve at idle, thermostatic means responsive to temperature ambient to the carburetor for restricting the movement of said cam at relatively low ambient temperatures independently of the choke valve and adapted upon increase of ambient temperature to release said cam for control by sai'd'choke valve.

5. In a carburetor for an internal combustion engine, said carburetor having'a throttle valve, a choke valve, 21 fast idle cam for limiting closing of thethrottle valve at idle, said cam being biased to move awayfrom a starting position, and a connection between the choke valve and the "cam adapted to hold the cam in Starting position when the choke valve isclosedadapted to allow movement of the cam away from its starting position on opening of the choke valve, and adapted to allow movement of the choke valve independently of the cam, thermostatic means responsive to temperature ambient to the carburetor for restricting the movement of said cam :at relatively low ambient temperatures independently of the choke valve and adapted upon increase of ambient temperature to release said cam for control by sa d choke valve.

6. A carburetor comprising 'amixture conduit, 'a'thro'ttle in said mixture conduit, adjust-able stop means for limiting the closing of said throttle, thermostat means substantially responsive to the temperature of air sup plied to said mixture conduit, an operating connection between said thermostat means and said adjustable stop means tending to restrict th'e'range of active positions of said adjustable stop at low 'air temperatures, and means responsive to movement of said throttle toward closed position to actuate said adjustable stop means.

7. A carburetor comprising a mixture conduit, athrottle valve and a choke valve in said mixture conduit, -a'djustable stop means for limiting the closing of said throttle, thermostat means responsive to engine operating temperatures toa'ctuate said choke valve, a connection between said thermostat means and said stop means for limiting 'the'closing of said throttle for operating'said stop-means into a range of active positions to increase engine idling speed by limiting the'closing of said throttle'when the engine is below normal operating temperature, a separate {the range-of,activepositions of said throttle-limiting stop means atllow air temperaures,v

,8.,A-carburetor compising a mir rtt ire'conduih a throt r16 valve and a choke valve in said mixture conduit ad- .-justable'stop means for limiting the closing of said throttle,

thermostat means responsive to engine operating temaeeasa t ,thermostatjmeans substantially responsive to thej-ttem mature i s p edrm's d a t J PP t n a :bflii esa dr sr atct e m st t teass 39 limiting .stop .';means 1 .bperating to restr1= en'g'ag eablej byf saidf arm? for; limiting ,closing'f U i a throttle' valve at idle, thermostatic ,means responsive Ito t a,

said-carburetor having a throttleishafh a thrdttle ivalve on saidshafh an arm on'saidshafh'a'choke valve,"and

a fast, idle c'am normally, controlled by the 'chokelyalve temperature ambient "to'the carburetor-forholdingsaid ambient temperatures.independently' of the choke valvfe V and adapted at higher temperatures to release said ,can': for-control by said choke valve, said thermostatic means peratures to actuat e said choke valve, a connectiorrbetween said thermostat means and said stop means for c limiting'the closing of said throttle for'operating said stop means into a range of active positions to increase engine idling speed by' limiting the closing of sai d throttle 7 when the engine isbelow normal operating temperatures,

a "separate thermostat means substantially responsive to the'temperatur'e of air supplied to said mixture conduit,

an operating connection between said separate thermostat means and said throttle limiting stop means tending to restrict the range of active positions of said limiting stop means at low air temperatures, and means responsive to movement of said throttle toward actuate said stop means. V

9. In'a carburetor for aninternal combustion engine, said carburetor having a throttle shaft, a throttle valve on said shaft, an armvon said shaft, and stop'means engageable by said arm for limiting closing of said gthrottlevalve at idle in accordance with engine temperature,t,thermostatic" means responsive to temperature ambient to the carburetor for holding said sto'p means closed position to c in an initial fast idle position at relatively low ambient temperatures independently of engine temperature and adapted at higher ambient temperatures to release said stop means, said thermostatic means comprising a; part on said arm and a part on said stop means, the part on said arm being free'to move with said arm in the direction, away fromthepart o'n said stop means whe said arm ismoved to open the throttle valve.

' 10. In a carburetor for an internal combustion engine,

said carburetor having a'throttle shaft athrottle valve .on said shaft, an-armon said shaft,;a fast idle cam engageable by said arm vbiaseclfronzl fast idle position to} 7 normal idle position limitingclosing of said throttle valve fat; idle, and means responsive to engine temperaturefor V adjusting the position of said came thermostatic; means responsive to temperature ambient, to thejcarburetor for holding 'said cam in itsfast idle" position at relatively 10w ambient temperatures independently of-engine temper'ature and adapted at;higher'ambient temperatures to release said cam for movement {to its normaljidle' posi tion, saidthermostatic means comprising a thermostatic element carried by said arm, andcga part on said c'am' cold, said thermostatic elementibeing adapted to bend away from said part on being heated and being free to' move with said arm away from said part when said arm is moved to open the throttle valve. j

11. In a carburetor for an internal combustion engine,

,saidcarburetor havinga throttle shaft, a throttle valve on saidshaft, an arm on said shaft, a choke'valve, and stop means actuated by thechoke valve engageableby H said armfo'r limiting closing of said throttle valve to vbetween fast idle and normal idle'positions, thermo- 1 static means responsive to'temperature ambient to the icarburetor for'holdingsaid stop means in an initial fast g'engageable by the thermostatic element when the latter is v V ,idle position at relatively low ambient temperatures independently of the choke valve-and adapted at higher ambient temperatures to releaseisaid stop means-forcontrol "by said choke valve, said thermostatic means ,comprising-a part on said and a'part ion said'stop means, a thepart on said 'arm'being free to move with saidjfarm inthe direction'away; from the part on s'aidstop means when said arm is movedtojopen the throttle valve.

1 12.111 a carburetor for an internal combustion engine,

idle, thermostatic means responsive to"temperature" am cam in a fast idle starting po'sitionj at relatively low comprising a thermostatic element carried by said arm, and a part on said cam engageable by the thermostatic ielement when the latter is.cold,'said thermostatic element sa d being adapted to bend away from said part on beingheated and being free to move with'said arm away from fsaid part when said arm ismo'ved to, open the throttle valve.

the cam in starting position when the choke'valve is closed, adapted to allow movement of the cam" away from its starting position on'o'pening of the choke valve,

and adapted to allow movement of the choke valve inde-'.

pendently' of the cam, thermostatic means responsive to temperature ambient to the carburetor for holding'said' cam in its starting position at relatively low ambient ternperatures independently of, the choke valve and adapted at higher ambient temperatures to releasesaid cam for control by said choke valve, said thermostatic means comprising a thermostatic blade fixed at one end on said arm, and a part onjsaid camengageable by said blade is moved toopen the throttle valve.

valve atidle in accordance with engine temperature, thermostatic means responsiv'e'to temperature ambient to the carburetor for'holding said position-controlling means in an initial position at relatively", low ambient temperatures independently 'of engine temperature and adaptedat higher ambient temperatures to release said position-controllingmeans, said thermostatic means comprising a thermostatic element having one end fixed-to the body of the carburetor and its other end engageable with said position-controlling means.

15. In a carburetor for an internal combustion engine,

said carburetorihaving a throttle shaft, a throttle valve on 7 said shaft, an arm on' said shaft,*a fast idle cam engageable by said arm for limiting closing of said throttle valve at idle, and means responsive to engine temperature for V controlling the position of said cam, thermostatic means responsive to temperature ambient to the 1 carburetor for V ,holdingtsaid cam in its starting'position at relativelyglow,

ambient temperatures independently of engine tempera-r @turerand adapted athigher ambient temperatures tore-'1 l3. Ina carburetor for an internal combustion engine, f

1 said carburetor having a throttle shaft, a throttle valve on said shaft," an arm on said shaft, a choke valve,,a-; fast idle cam engageable by said arm for limiting closing of the throttle valve at idle, said cam, being biased to move away from a starting position, and a connection; between the choke valve and the cam adapted to hold" lease'said cam-for response to'engine temperature, said V thermostatic means comprising a thermostatic element having, one end fixed'to the body'of theca rburetorland its other end erigageable with said Cam. 1 t i V 16. In a carburetor for, an-internal, combustion en-r c gine, said'carburetor havinga throttle V valve on said shaft, an arm on'said shaft, a choke valve, 1 I

and means controlled by the choke valve engageable by V said am for limiting closing of saidthrottle'valve at bient to the carburetor for liolding'sa'id position-control? shaft, a throttle ling means in an initial position at relatively low ambient temperatures independently of the choke valve and adapted at higher ambient temperatures to release said position-controlling means for control by said choke valve, said thermostatic means comprising a thermostatic element having one end fixed to the body of the carburetor and its other end engageable with said position-controlling means.

17. In a carburetor for an internal combustion engine, said carburetor having a throttle shaft, a throttle valve on said shaft, an arm on said shaft, a choke valve, and a fast idle cam controlled by the choke valve engageable by said arm for limiting closing of said throttle valve at idle, thermostatic means responsive to temperature ambient to the carburetor for holding said cam in its starting position at relatively low ambient temperatures independently of the choke valve and adapted at higher temperatures to release said cam for control by said choke valve, said thermostatic means comprising a thermostatic element having one end fixed to the body of the carburetor and its other end engageable with said cam.

18. In a carburetor for an internal combustion engine, said carburetor having a throttle shaft, a throttle valve on said shaft, an arm on said shaft, a choke valve, a fast idle cam engageable by said arm for limiting closing of the throttle valve at idle, said cam being biased to move away from a starting position, and a connection between the choke valve and the cam adapted to hold the cam in starting position when the choke valve is closed, adapted to allow movement of the cam away from its starting position on opening of the choke valve, and adapted to allow movement of the choke valve independently of the cam, thermostatic means responsive to temperature ambient to the carburetor for holding said cam in its starting position at relatively low ambient temperatures independently of the choke valve and adapted at higher ambient temperatures to release said cam for control by said choke valve, said thermostatic means comprising a thermostatic blade fixed at one end on the body of said carburetor and having its other end engageable with said cam.

19. In a multi-stage carburetor for an internal combustion engine, said carburetor having a primary throttle shaft, at least one primary throttle valve on said primary throttle shaft, an arm on said primary throttle shaft, a secondary throttle shaft, at least one secondary throttle valve on said secondary throttle shaft, a latch for locking the secondary throttle valve in closed position, a choke valve, and means controlled by the choke valve for releasing said latch and engageable by said arm for controlling the position of the primary throttle valve at idle, thermostatic means responsive to temperature ambient to the carburetor for holding said choke-controlled means in an initial position at relatively low ambient temperatures independently of the choke valve and adapted at higher ambient temperatures to release said choke-valvecontrolled means for control by said choke valve, said thermostatic means comprising a part on said arm and a part on said choke-valve-controlled means, the part on said arm being movable with said arm in the direction away from the part on said choke-valve-controlled means when said arm is moved to open the primary throttle valve thereby to allow said choke-valve-cont-rolled means to release said latch though the ambient temperature may be low.

20. In a multi-stage carburetor for an internal combustion engine, said carburetor having a primary throttle shaft, at least one primary throttle valve on said primary throttle shaft, an arm on said primary throttle shaft, a secondary throttle shaft, at least one secondary throttle valve on said secondary throttle shaft, a latch for looking the secondary throttle valve in closed position, a choke valve, a fast idle cam engageable by said arm for controlling the position of the primary throttle valve at idle and also adapted to release said latch, said cam being biased to move away from a starting position, and a connection between the choke valve and the cam adapted to hold the cam in starting position when the choke valve is closed, adapted to allow movement of the cam away from its starting position on opening of the choke valve, and adapted to allow movement of the choke valve independently of the cam, thermostatic means responsive to temperature ambient to the carburetor for holding said cam in its start-ing position at relatively low ambient temperatures independently of the choke valve and adapted at higher ambient temperatures to release said cam for control by said choke valve, said thermostatic means comprising a thermostatic blade fixed at one end on said arm, and a part on said cam engageable by said blade when the latter is cold, said blade being adapted to bend away from said part on being heated and being movable with said arm away from said part when said arm is moved to open the primary throttle valve thereby to allow said cam to release said latch though the ambient temperature may be low.

References Cited in the file of this patent UNITED STATES PATENTS

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