US2571181A - Carburetor control - Google Patents

Description

0d. 116, 1951 pm BALL 2,571,181

CARBURETOR CONTROL Filed Nov. 29, 1946 2 Sheets-Sheet l INVENTOR. 46 71071748 M341].

FTTORNZI'KS'.

Oct. 16, 1951 BALL 2,571,181

CARBURETOR CONTROL Filed Nov, 29, 1946 2 Sheets-Sheet 2 INVENTOR.

HTTOR/VL'KS'.

Patented Oct. 16, 1951 7 cnnnmm'ron CONTROL Thomas M. Ball, Detroit, Mich., assignor to Chrysler. Corporation, Highland Park, Mich., a corporation of Delaware Application November 29, 1946, Serial No. 713,051

. '1 Claim. (01. 123-179) 1 This invention relates to improvements in carburetors for internal combustion engines.

More particularly the invention relates to automatic choke control means for providing a proper fuel and air mixture during cranking and 5 parts are assembled vertically and are provided idling of a cold engine. with a tubular fuel mixture passage [6. The pas- Automatic choke controls which are operable in sage 16 has a restricted portion at I! which is response to engine temperature are commonly adapted to produce a Venturi effect in a manner provided on carburetors. A typical device of this well known in the art. A nipple I8 on body l2 type providesa bimetal element and means to ex- 10 is adapted to be connected by a fuel line, not pose this element to heat from the exhaust manishown, to a source of supply of fuel such as a fold. Expansion and contraction of the bimetal fuel pump, not shown. The air horn 13 serves element is utilized to move a choke valve controlas an inlet to the fuel mixture passage Hi. The ling the admission of air to the carburetor. These egress of the fuel mixture from the passage I 6 to devices are inadequate to properly accommodate the engine intake manifold is controlled by throtboth cranking and initial idling of a cold engine. tle valve l9. s I 7 If the thermostatic choke control is adjusted so The body portion of the carburetor is provided that the correct amount of air enters the carwith a fuel reservoir 20. The intake of fuel from buretor for engine cranking, then'an inadequate the nipple I8 is controlled by a needle valve 2| amount of air is present during engine idling. which is operated by a conventional float mecha- Similarly, if the thermostatic choke controlis adnism 22 which predetermines the fuel level in justed for engine idling then too much air is the reservoir. available for engine cranking under cold condi- The main fuel injection means controls the tions. The different requirements of engine mixture of air with fuel passing through metercranking and engine idling result from the fact 25 ing jet 23. Tubular passage 24 connects jet 23 that the lowest engine idling speed is many times with mixture chamber H5 at orifices 25. Tubular the speed of engine cranking. element 26 which is connected to the atmosphere It is an object of my invention to provide means by ducts, not shown, and is concentrically disto assure a fixed choke valve position during enp sed within passage 24 provides means for mixgine cranking below a predetermined temperan ing air with fuel in passage 24 in the usual ture. This means is adapted to overrule the ther-' manner. mostatic control under these conditions and to Liquid fuel for engi idling is drawn by maniprovide the optimum mixture for engine cranking. fold vacuum from passage 21 through passage 28 It is a further object of the invention to provide and passage 29 to idling jet 30. a thermostatic control that is adjusted for-the idling l s drawn through fice 3 in the desired mixture for engine idling and to provide Side Wal Of p e 15 and downwardly from a supplemental means to overrule the thermofice 32 in the air horn through passage 29. A static control to provide the proper mixture for conventional choke valve 35 is pinned to a shaft engine cranking. The choke valve is drawn by 36 which is rotatably mounted transversely of the said means to its substantially closed or engine 40 air horn. The position of the valve 35 in the air cranking position and retained in this position horn 13 may be varied by rotation of the shaft 35 during engine cranking below a predetermined and this position will determine the restriction temperature. to the passage of air from the air horn l3 through In the drawings: the mixture passage Hi. The valve 35 is prefer- Fig. 1 is a vertical section of a carburetor 5 ably mounted off center on the shaft 36 so that equipped with my invention and the associated the Weight of the Valve and t e passage of a r intake and exhaust manifolds of an internal comwill tend to maintain h V lve in i p D bustion engine; tion. When the engine is being cranked by oper- Fig. 2 is a vertical section on the line 2-2 of ation of the conventional starting motor, it is de- Fig.1; sirable to have the valve 35 substantially fully Fig. 3 is a vertical section of the bimetallic eleclosed so that it blocks the air horn l3. Bleed ment taken on the line 33 of Fig. 1; hole 31 and a small spring-loaded valve 38 are Fig. 4 is a vertical elevation partly broken away provided to maintain a small flow of air into the and taken on the line 4-4 of Fig. l and mixture passage [6 under these conditions.

Fig. 5 is a wiring diagram including the start- A chamber 40 provided on the side of the air ing motor and electric c oke control means.

Referring to the drawings, the carburetor I0 is secured to the engine intake manifold H. The carburetor comprises a body 12, an air horn l3, an insulator l4, and a body flange I5. These Air for the horn I3 houses a bimetallic coil element 4| which aotinsi A passage 41 connects the housing Wtv'ithtlie' lower portion of the mixture passage |6.'=There' is thus provided a means forcirculating warni air taken from the vicinity of the exhaust manifold around the bimetallic elementfll. The suction present in the intake manifold ofthangi'ne adjacent the end portion within the opening 45.

4 only air permitted to enter the mixture passage I6 comes through the bleed hole 31 and spring-controlled valve 38 in the choke valve 35. when the choke valve is rotated sufficiently by the expansion of the bimetallic coil element 4| under warm conditions, the lever 60 is moved away from the-solenoid 52 sufficiently so that the magnetic field of the 'solenoid 52 does not have thestrength necessary to move the lever 60 to the position 5|. 'Jlhus at some predetermined temperature th rou gh the influence of the bimetallic coil elern'ent4 Ithe lever 60 is moved out of operative re l'aticnshipi-with thesolenoid 52. Actuation of the :solenoidi'52 as-an": incident to operation of the 'star'ten switch wl is, therefore, only effective below a predetermi ned temperature, to move the choke'valv 35 to the position 5|.

draws air from housing it] through passage 'fl aiid this air is replaced by warm air drawn from the opening 45'into the housing' through the tube "44. The' temperature of the 'coil elementyfl is -thus dependent upon the: engine operating tem- ?perature and the expansion and contractionv of "'the' coil element 4| rotates the'shaft 36 to posi- 4 tion the valve 35 in a position which is'contr'o'lled f by engine temperature.

'The choke valve 35 and bimetallic coil' element 4| may be adjusted sothat under'coldiconditions the valve 35 will'bemoved to a partially closed 3 position which is known to produce theoptimum f fuel mixture for'engine idling conditions. "This position is designated-by the numeral 5!) in'Fig. 4.

When'cranking the 'engineunder similarcon- *these" two conditions, it is necessary to'provide supplemental means to force the'choke'valve" 35 ito-the position 5| understarting conditions. To

accomplish this I have provided a" 'so1enoid"52 "which is secured bybolts53 to the'air horn l3. The solenoid 52 is connected in parallel' with the starting motor as illustratedinFig. 5. "The usual storage battery 53 throughline' 54 is connected to the starting motor 55. Line 55 connects the starting motor with a starter switch 51. Line' 58 connects the starter switch with the battery 53. The

, from a magnetic material" and when it is in the field of the solenoid 52 and the'solenoidis'energized by the operation of the starter 'swit'ch 51, the lever 60 is attractedto the solenoid 52"and assumes the position designated by'the numeral 6| in Fig. 4. When the'lever 60 isin the position "6|', the choke valve 35'isinthepositiori- 5|. The choke valve 35 when in the position 5|, complete- 'ly blocks the passage in the air'horn "l3 and'the diti ons, it is desirable to have the choke valve'35 :in an even further closed position designated by ithe numeral-5| 'in Fig; 4. Since the'temperature m: the bimetallic coil element 4| is the same under I "Number :Thebimetallic coil element 4| is thus adapted to control the positionfi'of the choke valve 35 between the limits illustrated by the position. 50xand the full openposition 62 illustrated in F-ig. 4/ The solenoid 52;,and lever 60 areadaptd to inove'the choke valve 35 to the position 5| in-Fig. l provid- '-ing that the solenoid 52 is-actuated below aipredetermined temperature when thelever- 63. isLin close proximity to the solenoid 52.

In an internal combustion engine havinga carburetor adapted to mix-air and fueland aselfstarter adapted to crank said engine, -a.ch'ol e valve mounted upon a shaft and rotatable insaid carburetor to regulate between limits the proportion'of air in said mixture, a thermostatic device operable to control said valve by rotation of said shaftv in'responserto changes in engine temperaturewithin arpredetermined. temperature range, anelectromagnetic device associated with said valve and operable to'establish'a predetermined .fuel and'air mixture withincertain temperature limits included in saidtemperature range,--said electromagnetic device including a stationary solenoid'and an element keyed to said shaft. and adapted to be attracted by said solenoid,.-;said solenoid and said shaft being so positioned that rotation'ofsaid' shaft beyond apredetermined limit in response to increased engine-temperature removessaid element from the effective field of said s'ole'noid andimeans to energize said solenoid as an incidentv to each actuation of said selfstarter.

'THOMAS M.'BALL.

REFERENCES -C ITED 'The following referencesare of recordin the file of this patent:

' UNITED STATES PATENTS Name Date 'Willmore et al June.12 -,-1934 Hunt Apr, 2,1935 Sisson Aug. 23, 1938 Schweiss Dec. 24,1940 Langhaar May 29,1945

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