US3907943A - Automatic choke for a carburetor - Google Patents

Automatic choke for a carburetor Download PDF

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Publication number
US3907943A
US3907943A US430663A US43066374A US3907943A US 3907943 A US3907943 A US 3907943A US 430663 A US430663 A US 430663A US 43066374 A US43066374 A US 43066374A US 3907943 A US3907943 A US 3907943A
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US
United States
Prior art keywords
coil
bimetallic
bimetallic coil
housing
carburetor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US430663A
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English (en)
Inventor
Hidenori Tateno
Masami Konishi
Hisaharu Arai
Kenji Koeda
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Toyota Motor Corp
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Toyota Motor Corp
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Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
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Publication of US3907943A publication Critical patent/US3907943A/en
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Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
    • F02M1/08—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically
    • F02M1/10—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically dependent on engine temperature, e.g. having thermostat

Definitions

  • ABSTRACT A bimetallic coil for an automatic choke for a carburetor on a vehicular engine, which is provided with means for holding the bimetallic coil against vibration.
  • the means for holding the bimetallic coil against vibration comprises, for example, a plurality of pins or an elongate wall type structure positioned in proximity to the coil so as to be contacted by or contact the loops formed on the coil upon thermal deformation of the coil or the coil and the means to thereby prevent or at least reduce the vibration of the coil during the operation of the engine.
  • FIGA A first figure.
  • This invention relates to. a bimetallic strip in coiled form for an automatic choke in a carburetor on a motor vehicle, and more particularly to such a bimetallic strip provided with anti-vibratory means.
  • the bimetallic strip in coiled form is often found to vibrate with the vibration of an engine during a certain period of the engine operation when the strip has become hot and deformed with its outer end disengaged from a choke lever on a choke valve and hanging freely.
  • the stress exerted on the strip by its vibration often exceeds the maximum allowable stress for the strip, resulting in breakage of thestrip and failure of the choke.
  • the vibration of the strip tends to occur even when it is maintained in engagement with the choke lever, though less often than when its outer end is hanging freely.
  • an automatic choke for a carburetor on a motor vehicle comprising a valve member positioned within a carburetor housing, a valve shaft secured to the valve member and rotatably supported on the carburetor housing at both ends, one of which ends has an extension projecting outwardly from the carburetor housing, a crank connected to the extension of the valve shaft and forming a lever and a bimetallic coil positioned within a housing joined to the carburetor housing and having an inner end secured to the housing and an outer end normally engaged with the lever to urge it in a direction which keeps the valve member closed
  • this invention provides an improvement in the bimetallic coil which is provided with means for preventing the coil from vibrating during the operation of an engine.
  • the means for preventing the vibration of the bimetallic coil comprises a plurality of pins standing from the floor of the coil housing and adapted to be contacted by the outer edge of the coil when the coil tends to vibrate.
  • the means may alternatively comprise a curved wall structure standing from the floor of the coil hous ing in proximity to the coil periphery and extending along a portion of the coil periphery to be contacted by the coil when the coil tends to vibrate.
  • a modified form of the wall type means comprises a channel-shaped double wall structure standing from the floor of the coil housing and enclosing a portion of the outermost turn of the coil.
  • the inner and outer walls of this wall type means are adapted to be contacted by the coil when the coil tends to vibrate.
  • a further alternative may comprise a pair of oppositely disposed curved walls surrounding the coil and be formed from a bimetallic strip.
  • these bimetallic walls may be deformed to contact the coil to prevent it from vibrating.
  • the wall type means may be secured to the inner side wall of the coil housing.
  • FIG. 1 is a front elevational view in verticalsection of an automatic choke for a vehicular carburetor incorporating the principles of this invention
  • FIG. 2 is a top plan view showing a preferred embodiment of this invention
  • FIG. 3 is a top plan view'showing another preferred embodiment of this invention.
  • FIG. -4 is a cross-sectional '-view taken along line IV -IV of FIG. 3;
  • FIG. 5 is a top plan view showing still another preferred embodiment of this invention.
  • FIG. 6 is a top-plan view showinga further preferred embodiment of this invention.
  • FIG. 7 is a cross-sectional view taken along line VII- VII of FIG. 6;
  • FIG. 8 is a cross-sectional view showing amodified form of the embodiment'shown in FIG. 7; I
  • FIG. 9 is a top plan view showing a still furtherpreferred embodiment of this invention.
  • a FIG. 10 is a graph illustrating the effect of this invention.
  • I? 1 Referring to FIG. .1 of the'drawings, a housing "1 is joined by bolts 17V to a housing 11 for a carburetorC, and a bimetallic coil 2 is positioned within the housing 1.
  • the bimetallic coil 2 is formed from two metals, and the inner metal has a smaller coefficient'of linear "expansion than the outer metal.
  • the bimetallic coil 2 has an inner end 2a secured to a shaft 4 standing from the floor 3 of the housing 1, and is a left-hand coil.
  • a valve member 5 is positioned within the housing 11 for the carburetor C and secured to a rotatable shaft 6 rotatably supported by the housing 1 l.
  • the shaft 6 has an outward extension at one end and a' crank 7a is secured to the extension of the shaft 6.
  • the free end of the crank 7a forms a lever 7 extending into the housing 1 for the bimetallic coil 2.
  • a coilspring 18 is positioned between the wall of thecarburetor housing 11 and the crank 7a and encircles the extension of the shaft 6 to urge the valve member 5 to open.
  • the bimetallic coil-2 has a bend 8 at its outer end as shown in FIG. 2, and the bend 8 is adapted to normally engage the lever 7 to urge it in a direction (to the right in FIG.
  • a plurality of pins 9 stands from the floor3 of the housing 1 and cooperate to surround the bimetallic coil 2 in proximity thereto as illustrated in FIG. 2.
  • the pins 9 are spaced from one another and each'pin 9 is preferably positioned so as to be contacted by one of the loops or antinodes formed on the bimetallic coil 2 when it vibrates during the operation of the engine.
  • a heating element 10 is provided between the bimetallic coil 2 and the floor 3 of the housing 1 and adapted to be actuated in response to elevation of the temperature in the vicinity of the engine to deform the bimetallic coil 2 to open the valve member 5 at a predetermined time after the engine is started.
  • this tendency can be considerably reduced or prevented when the bimetallic coil 2 contacts the pins 9. Accordingly, the stress exerted on the bimetallic coil 2 by its vibration can be maintained below its fatigue limit, so that the bimetallic coil 2 will never be broken by vibration.
  • FIG. 10 illustrates the relation between the clearance between the bimetallic coil 2 and the pins 9 and the stress exerted on the bimetallic coil 2 by its vibration during a certain period of the engine operation. It will be noted from this graph that proper selection of the positions of the pins 9 can effectively reduce the stress exerted on the bimetallic coil 2 by its vibration and can accordingly prevent breakage of the bimetallic coil 2 due to vibration.
  • the means for preventing vibration of the bimetallic coil 2 comprises a curved wall 12 standing from the floor 3 of the housing 1 and surrounding the bimetallic coil 2 in proximity thereto.
  • the wall 12 can obviously provide a much larger surface of contact with the bimetallic coil 2 than the pins 9 as hereinbefore described can, so that the wall 12 can produce a so much greater effect in the prevention of the vibration of the bimetallic coil 2 than the pins 9.
  • the wall 12 also provides the bimetallic coil 2 with an excellent wear resistance and an excellent fatigue strength.
  • the wall 12 is preferably so provided as to surround that portion of the bimetallic coil 2 in which loops are formed when the coil 2 vibrates.
  • a modified form of bimetallic coil 13 comprises a right-hand coil in which the inner metal has a larger coefficient of linear expansion than the outer metal.
  • the inner end of the bimetallic coil 13 is fastened to the shaft 4.
  • a bend 14 is formed at the outer end of the coil 13 and a channel-shaped strip 15 is attached to the bend 14.
  • the channel-shaped strip 15 is engaged with the lever 7 to urge it in a direction (to the right in FIG. 5) which keeps the valve member 5 closed.
  • the bimetallic coil 13 is heated by the heating element 10, the coil 13 expands and somewhat increases its diameter.
  • the coil 13 contacts the pins 9 and the channelshaped strip 15 at the outer end of the coil 13 disen gages itself from the lever 7.
  • the coil 13 hangs freely at its outer end, while it is secured at its inner end, but
  • the means for preventing vibration of the bimetallic coil 2 comprises a channel-shaped curved double wall structure 19 standing from the floor 3 of the housing 1.
  • the double wall structure 19 encloses the outermost turn of the bimetallic coil 2 with its inner and outer walls and top wall spaced from the coil 2.
  • the double wall structure 19 is preferably so positioned as to cover that portion of the bimetallic coil 2 in which loops may be formed when the coil 2 vibrates.
  • FIG. 8 shows a modified form of curved channelshaped double wall structure 19a adapted to be contacted by the coil 2 when the latter starts vibrating.
  • the double wall structure 19a is similar to the double wall structure shown in FIG. 7 both in construction and in function except that it is supported on the side wall 3a of the housing 1 instead of standing from the floor 3.
  • FIG. 9 The modified structure shown in FIG. 9 comprises a pair of substantially arcuate bimetallic strips 16 supported on the floor 3 of the housing 1 at one end. Each of the arcuate strips 16 consists of two metals having different coefficients of expansion, and the outer metal of each strip 16 has a greater coefficient of expansion than the inner metal thereof.
  • the other ends of the arcuate strips 16 are hanging freely and extend along the outer periphery of the bimetallic coil 2 in proximity thereto.
  • the outer metal constituting the bimetallic coil 2 has a greater coefficient of expansion than the inner metal thereof as stated before. Because of their construction as described above, the arcuate strips 16 decrease their radii, when heated, to contact or approach the bimetallic coil 2 to prevent or reduce the vibration of the bimetallic coil 2 when the latter is disengaged from the lever 7 to allow the valve member 5 to fully open. It will be noted that the arcuate strips 16 may alternatively be supported on the side wall 3a of the housing 1.
  • the means for preventing the vibration of the bimetallic coil may comprise a bar or strip of metal having a large coefficient of thermal expansion supported on the side wall 3a of the housing 1 perpen dicularly thereto and having its free end located in a position where it may be contacted by each loop formed on the bimetallic coil when the latter vibrates.
  • the bar or strip expands and its free end contacts the bimetallic coil to prevent the latter from vibrating.
  • said wall is made of a bimetallic strip having a larger coefficient of thermal expansion than the material of which said bimetallic coil is made, said opposite end of said wall being adapted to bend toward said bimetallic coil and contact the outer peripheral surface thereof when said wall is brought to an elevated temperature.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Means For Warming Up And Starting Carburetors (AREA)
US430663A 1973-07-13 1974-01-04 Automatic choke for a carburetor Expired - Lifetime US3907943A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP48079508A JPS5239980B2 (enrdf_load_stackoverflow) 1973-07-13 1973-07-13

Publications (1)

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US3907943A true US3907943A (en) 1975-09-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
US430663A Expired - Lifetime US3907943A (en) 1973-07-13 1974-01-04 Automatic choke for a carburetor

Country Status (3)

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US (1) US3907943A (enrdf_load_stackoverflow)
JP (1) JPS5239980B2 (enrdf_load_stackoverflow)
GB (1) GB1465071A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4058097A (en) * 1975-06-30 1977-11-15 Texas Instruments Incorporated Choke control
US4131099A (en) * 1976-01-24 1978-12-26 Robert Bosch Gmbh Idling and warm-up fuel control device
US4152377A (en) * 1977-12-22 1979-05-01 Toyota Jidosha Kogyo Kabushiki Kaisha Tamperproof automatic choke
EP0051925A3 (en) * 1980-11-06 1982-12-08 Texas Instruments Incorporated Fuel supply system with automatic choke

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS543622A (en) * 1977-06-08 1979-01-11 Hitachi Ltd Automatiac choke mechanism of carburetor
JPS5443941U (enrdf_load_stackoverflow) * 1977-09-01 1979-03-26
JPS6410727A (en) * 1987-07-02 1989-01-13 Fujitsu Ltd Semiconductor differential circuit

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2074728A (en) * 1932-12-22 1937-03-23 Bendix Aviat Corp Carburetor
US2423059A (en) * 1943-02-18 1947-06-24 Bendix Aviat Corp Carburetor
US2571602A (en) * 1948-07-16 1951-10-16 Edwin P Neuser Carburetor choke
US2657862A (en) * 1950-12-07 1953-11-03 Carter Carburetor Corp Stabilizer for overrunning thermostatic controls
US2715500A (en) * 1950-04-19 1955-08-16 Carter Carburetor Corp Automatic choke control device
US2939445A (en) * 1957-03-18 1960-06-07 Holley Carburetor Co Means for starting and operating internal combustion engines
US3278119A (en) * 1964-07-10 1966-10-11 Gen Motors Corp Automatic choke auxiliary thermostat

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2074728A (en) * 1932-12-22 1937-03-23 Bendix Aviat Corp Carburetor
US2423059A (en) * 1943-02-18 1947-06-24 Bendix Aviat Corp Carburetor
US2571602A (en) * 1948-07-16 1951-10-16 Edwin P Neuser Carburetor choke
US2715500A (en) * 1950-04-19 1955-08-16 Carter Carburetor Corp Automatic choke control device
US2657862A (en) * 1950-12-07 1953-11-03 Carter Carburetor Corp Stabilizer for overrunning thermostatic controls
US2939445A (en) * 1957-03-18 1960-06-07 Holley Carburetor Co Means for starting and operating internal combustion engines
US3278119A (en) * 1964-07-10 1966-10-11 Gen Motors Corp Automatic choke auxiliary thermostat

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4058097A (en) * 1975-06-30 1977-11-15 Texas Instruments Incorporated Choke control
US4131099A (en) * 1976-01-24 1978-12-26 Robert Bosch Gmbh Idling and warm-up fuel control device
US4152377A (en) * 1977-12-22 1979-05-01 Toyota Jidosha Kogyo Kabushiki Kaisha Tamperproof automatic choke
JPS5487335A (en) * 1977-12-22 1979-07-11 Toyota Motor Corp Automatic yoke system
EP0051925A3 (en) * 1980-11-06 1982-12-08 Texas Instruments Incorporated Fuel supply system with automatic choke

Also Published As

Publication number Publication date
GB1465071A (en) 1977-02-23
JPS5239980B2 (enrdf_load_stackoverflow) 1977-10-08
JPS5026916A (enrdf_load_stackoverflow) 1975-03-20

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