US3554500A - Carburetor idle system control - Google Patents

Carburetor idle system control Download PDF

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Publication number
US3554500A
US3554500A US789262A US3554500DA US3554500A US 3554500 A US3554500 A US 3554500A US 789262 A US789262 A US 789262A US 3554500D A US3554500D A US 3554500DA US 3554500 A US3554500 A US 3554500A
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United States
Prior art keywords
passage
fuel
emulsion
air
idle
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Expired - Lifetime
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US789262A
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English (en)
Inventor
Laszlo Hideg
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Ford Motor Co
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Ford Motor Co
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Publication date
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Publication of US3554500A publication Critical patent/US3554500A/en
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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
    • F02M3/00—Idling devices for carburettors
    • F02M3/08—Other details of idling devices
    • F02M3/12—Passageway systems

Definitions

  • McCollum ABSTRACT A downdraft-type carburetor has an idle system 1 including an emulsion passage that is relatively large in diameter in comparison to a reduced diameter outlet from the emulsion passage that is connected to the main induction passage below the throttle valve, the emulsion passage containing a fuel jet that directs the fuel stream axially through the center of the emulsion passage to essentially eliminate wetting of the walls with fuel to thereby minimize random fluctuations of the fuel flow and provide a more finite control of idle fuel flow.
  • This invention relates, in general, to a carburetor for an internal combustion engine. More particularly, it relates to the idle system for such a carburetor.
  • a major source of the random fuel discharge fluctuations from the idle system is the emulsion passage.
  • the latter is the passage between the idle fuel jet and the idle system outlet hole which is connectedto the main induction passage down stream of the throttle plate. Air from the idle air bleed and fuel from the idle fuel jet flow through the emulsion passage and enter the carburetorbore through this outlet hole.
  • the flow velocities are relatively low in the unrestricted emulsion passage and become high in the restricted outlet hole.
  • FIG. la is a cross-sectional viewof the carburetor portion illustrated in FIG. 1 with, however, the plane of viewing rotated slightly from that position shown in FIG. 1;
  • FIG. 2 and 2a are cross-sectional views corresponding to FIGS. 1 and la and illustrating a modified embodiment of the invention.
  • FIG. 3 is a cross-sectional view of a downdraft type carburetor illustrating a further modification of the invention.
  • FIG. 1 illustrates a portion of a conventional downdraft type carburetor that is commonly used with internal combustion engines of the axially reciprocable' piston type. More specifically, carburetor portion 10' includes the usual main air fuel induction passage 12. At its upper end 14, it is adapted to be connected through an air cleaner, not shown, to a source of air at essentially atmospheric pressure. At its lower end 16, it is adapted to be connected to the intake manifold of the engine so: as to be subject to the changing vacuum therein upon 1 changes in engine operation, in a known manner.
  • the idle fuel systems generally are adjusted to provide a richer mixture than desirable under average conditions.
  • Automobile engines could be operated with leaner mixtures 'at light and medium loads if the random'fuel discharge fluctuation andthe fuel temperature and vapor pressure sensitivity of the idle fuel system was decreased. Leaner carburetor adjustment would improve the fuel economy and the exhaust gas composition. 1
  • FIG. 1 is a cross-sectional view of aportion of a downdraft type carburetor embodying the invention
  • Induction passage 12 also includes the usual fixed venturi section 18 and a throttle valve 20. ;The latter is rotatably mounted upon a shaft 22 joumaled in the sidewalls of the carburetor housing. Throttle valve 20 is movable between the engine idle speed position shown, essentially closing induction passage 12, and a wide open throttle position 24 indicated by dotted lines. 1
  • the carburetor would include the usual main fuel discharge nozzle generally located in or adjacent venturi 18. The latter would be subject to the change in air flow through the venturi to meter the main supply of fuel to the engine, in a known manner.
  • the idle system ofv the carburetor includes a relatively large diameter emulsion passage '26 that, in this instance, is essentially parallel to main induction passage 12.
  • the upper end 28 of the passage is intersected by an air inlet passage 30 that is connected to the airhorn section 14 of the main induction passage so as to communicate with air at essentially atmospheric pressure.
  • the air inlet passage contains the usual fixed area orifice 32 that provides a pressure drop thereacross and controls the vacuum signal in emulsion passage 26 in a manner to be described.
  • emulsion passage 26 The lower portion of emulsion passage 26 is tapered to connect to a relatively small diameter outlet passage 34. The latter is intersected by a further passage 36 connected to induction passage 12. Passage 36 is, controlled in this case by a needle valve 38 slidably mounted in a side bore 40 through a seal 42. Passage 36 communicates with the main induction passage 12 ata' point below the closed position of throttle valve 20 so as always to be subject to the vacuum in the intake manifold of the engine. 1
  • the vacuum acting in passages 36 and 34 and emulsion passage 26 causes a pressure drop across the air'orifice 32 and'a' vacuum signal in emulsion tube 26 that varies as a function in the changes in the vacuum of intake manifold, in a known manner.
  • the upper end of emulsion passage 26 has mounted therein a fuel jet 44, which in this case, is in the form of a nozzle having an elongated orificed outlet 46.
  • the upper end 48 of the fuel jet is open to a passage 50 containing fuel-52 supplied thereto from the carburetor fuel bowl, not shown.
  • the fuel jet 44 constructed and positioned to direct the fuel axially through outlet 46 in essentially a straight line through the center of the relatively large diameter emulsion tube or passage 26 directly toward outlet 34 so that very little if any of the fuel wets the walls of the emulsion passage; i.e., the fuel flows in a relatively small diameter stream through the center of emulsion passage 26 essentially without contacting the walls of the passage. This minimizes fuel evaporation in passage 26.
  • Nozzle 44 also is positioned to project into the intersection between air inlet passage 30 and emulsion passage 26 so as to be washedby the flow of air past the nozzle to permit liquid fuel to be drawn from the passage. 50, where the fuel. essential atmosphere pressure acting on it.
  • FIG. 1 also shows a conventional transfer port 54 that, in this case, straddles the idle speed. position of throttle valve 20. Air flowing into and out of the large transfer slot may form eddies or turbulences which would disturb the fuel flow in passage 26 by creating fluctuation in flow rate. Therefore, in
  • the transfer slot or. is not connected directly to emulsion passage 26 but by a smallside passage 56 containing an orifice or flow restricting 8
  • the latter not only perrnits the use of a small passage 56. that reduces the likelihood of liquid fuel-accumulation in the side cavity, but also p ermits the use of a practical size transfer slot or port 54-while isolating the flow fluctuations therein from passage 26.
  • thefair, inlet passage 3t); corresponding to passage 30 il'tElQ L in this case contains an adjustable variable area orifice, 32f. latter consists of a manually adjustable needle valve projecting into a cooperating portion of passage 31) as shown.
  • the transfer port or slot 54' in thisin ee has a separate connection to the air inlet passage 31] insteadof to the emulsion passage 26 in no. 1.
  • passage 56 is connected to passage 56. Furthermore, small diameter outlet: passage 36 in this case is connectedto the maininduction passage without the inclusion of the, adjustable screw, 38
  • HQ. 2 operates essentially the sameas the FlG. lembodiment,
  • ' BIG. 3- shows a still ful' mqmodification to the carbaretor idle system illustrated inFlGS; 1, 1 6,2 and in FIG 3, emulsion passage 26," at its le wierfend intersects the transfer cavity 56", the latter beingjsolatedfromthe transfer port orslotby abaffle or flowrest'rictor 5 8?.
  • Theupper portion of emulsion passage 26" is connected by an air inlet passage 30" centaining a manually adjust able. needle valve 32" similar to theElG. 2showing.
  • the discharge of fuel through nozzle 44" causes the fuel to cling to and flow along the wire surface from the inlet to the outlet portion.
  • the wire core increases the stability of the. fuel jet because the surface tension makes the fuel adhere to the wire. Accordingly, very little if any fuel wets the walls of the emulsion passage 26", which essentially eliminates idle fuel flow fluctuations in the emulsion passage.
  • the high outlet velocity passage 36' could be made with two different diameters instead of a single constant diameter shown; also, both the low velocity and high velocity emulsion passages could be made shorter, than shown and with irregular shapes so long as the fuel stream is injecteddirectlyinto the hole of the, high velocity emulsion passage.
  • the adjustability of the idle mixture can be provided; by an additional adjustable air bypass passage connecting theiair passage of the idle .system.
  • L'An idle air fuel-system for a carburetor having a main induction passage having one end connected to a source of air at essentiallyatmospheric pressure and its other end adapted to be connectedtothe intake manifold of an internal combustion engine to'be subject to the change in vacuum thereinand a throttle valye mounted across said passage to control flow therethroughandrotatably movable between an engine idle speed position essentially closing said main.
  • said-idle system including an air fuel emulsion passagein a circuit.in parallel to said main passage, said emulsionpassagerhaving an air inlet atone end connected to said mainfinductionpassage at a location anterior of said throttle valveanda restricted fuel-air outlet at the opposite end connected to saidginduction passage at a location posterior of said throttlevalve, said one end of saidemulsion passage containing a fueljet connectedto a source of fuel and positioned in the path ofiflow of air therepast from said air inlet and man attitude effectingadischarge of fuel therefrom essentially along the axis ofsaid'emulsion passage, said latter passage being of a' of srnaller cross-sectional area connecting said transfer port to said emulsion passage, and flow restricting means in said latter means to control flow therethrough to minimize disturbances to flowsthroughsaid emulsion passage.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of The Air-Fuel Ratio Of Carburetors (AREA)
  • Nozzles For Spraying Of Liquid Fuel (AREA)
  • Spray-Type Burners (AREA)
  • Fuel-Injection Apparatus (AREA)
US789262A 1969-01-06 1969-01-06 Carburetor idle system control Expired - Lifetime US3554500A (en)

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US78926269A 1969-01-06 1969-01-06

Publications (1)

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US3554500A true US3554500A (en) 1971-01-12

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US789262A Expired - Lifetime US3554500A (en) 1969-01-06 1969-01-06 Carburetor idle system control

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US (1) US3554500A (enrdf_load_stackoverflow)
CA (1) CA918019A (enrdf_load_stackoverflow)
DE (1) DE2000301C3 (enrdf_load_stackoverflow)
GB (1) GB1233820A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711069A (en) * 1969-08-15 1973-01-16 Ford Motor Co High velocity carburetor idle system
US3796415A (en) * 1972-08-17 1974-03-12 Colt Ind Operating Corp Carburetor fuel transfer discharge port
US4124662A (en) * 1974-05-02 1978-11-07 Nissan Motor Company, Limited Carburetor and method of operating same
US4377141A (en) * 1980-07-30 1983-03-22 Hitachi, Ltd. Low speed fuel supply system for a carburetor
US5948325A (en) * 1996-06-13 1999-09-07 U.S.A. Zama, Inc. Air-fuel ratio adjustment device for carburetor
US20240075421A1 (en) * 2009-02-27 2024-03-07 Donaldson Company, Inc. Filter cartridge; components thereof; and methods

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1865851A (en) * 1929-08-09 1932-07-05 Edward F Geiger Liquid flow-controlling device
US1935350A (en) * 1930-07-22 1933-11-14 Bendix Stromberg Carburetor Co Carburetor
US2066003A (en) * 1934-06-06 1936-12-29 Victor R Heftler Carburetor
US2127444A (en) * 1934-05-23 1938-08-16 Borg Warner Carburetor
US2568987A (en) * 1946-12-20 1951-09-25 Bendix Aviat Corp Carburetor
US2701709A (en) * 1947-03-05 1955-02-08 Bendix Aviat Corp Carburetor by-pass control
US2852240A (en) * 1955-11-07 1958-09-16 Holley Carburetor Co Carburetor
US3408054A (en) * 1967-07-26 1968-10-29 Walker Brooks Carburetor
US3454264A (en) * 1967-04-27 1969-07-08 Chrysler Corp Idle mixture control for carburetors

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1865851A (en) * 1929-08-09 1932-07-05 Edward F Geiger Liquid flow-controlling device
US1935350A (en) * 1930-07-22 1933-11-14 Bendix Stromberg Carburetor Co Carburetor
US2127444A (en) * 1934-05-23 1938-08-16 Borg Warner Carburetor
US2066003A (en) * 1934-06-06 1936-12-29 Victor R Heftler Carburetor
US2568987A (en) * 1946-12-20 1951-09-25 Bendix Aviat Corp Carburetor
US2701709A (en) * 1947-03-05 1955-02-08 Bendix Aviat Corp Carburetor by-pass control
US2852240A (en) * 1955-11-07 1958-09-16 Holley Carburetor Co Carburetor
US3454264A (en) * 1967-04-27 1969-07-08 Chrysler Corp Idle mixture control for carburetors
US3408054A (en) * 1967-07-26 1968-10-29 Walker Brooks Carburetor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711069A (en) * 1969-08-15 1973-01-16 Ford Motor Co High velocity carburetor idle system
US3796415A (en) * 1972-08-17 1974-03-12 Colt Ind Operating Corp Carburetor fuel transfer discharge port
US4124662A (en) * 1974-05-02 1978-11-07 Nissan Motor Company, Limited Carburetor and method of operating same
US4377141A (en) * 1980-07-30 1983-03-22 Hitachi, Ltd. Low speed fuel supply system for a carburetor
US5948325A (en) * 1996-06-13 1999-09-07 U.S.A. Zama, Inc. Air-fuel ratio adjustment device for carburetor
US20240075421A1 (en) * 2009-02-27 2024-03-07 Donaldson Company, Inc. Filter cartridge; components thereof; and methods
US12370486B2 (en) * 2009-02-27 2025-07-29 Donaldson Company, Inc. Filter cartridge; components thereof; and methods

Also Published As

Publication number Publication date
DE2000301A1 (de) 1970-08-27
DE2000301C3 (de) 1974-05-22
CA918019A (en) 1973-01-02
GB1233820A (enrdf_load_stackoverflow) 1971-06-03
DE2000301B2 (de) 1973-10-25

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