US3761063A - Carburetor provided with auxiliary fuel feed means - Google Patents

Carburetor provided with auxiliary fuel feed means Download PDF

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Publication number
US3761063A
US3761063A US00131165A US3761063DA US3761063A US 3761063 A US3761063 A US 3761063A US 00131165 A US00131165 A US 00131165A US 3761063D A US3761063D A US 3761063DA US 3761063 A US3761063 A US 3761063A
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US
United States
Prior art keywords
throttle valve
fuel
passage
injection nozzle
auxiliary fuel
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
US00131165A
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English (en)
Inventor
A Shibanaka
H Takayama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nikki Co Ltd
Mazda Motor Corp
Original Assignee
Nippon Carburetor Co Ltd
Toyo Kogyo Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Carburetor Co Ltd, Toyo Kogyo Co Ltd filed Critical Nippon Carburetor Co Ltd
Application granted granted Critical
Publication of US3761063A publication Critical patent/US3761063A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F02M13/00—Arrangements of two or more separate carburettors; Carburettors using more than one fuel
    • F02M13/02—Separate carburettors
    • F02M13/04—Separate carburettors structurally united
    • F02M13/046—Separate carburettors structurally united arranged in parallel, e.g. initial and main carburettor
    • 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
    • F02M7/00—Carburettors with means for influencing, e.g. enriching or keeping constant, fuel/air ratio of charge under varying conditions
    • F02M7/04—Means for enriching charge at high combustion-air flow
    • 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
    • F02M7/00—Carburettors with means for influencing, e.g. enriching or keeping constant, fuel/air ratio of charge under varying conditions
    • F02M7/12—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves
    • F02M7/133—Auxiliary jets, i.e. operating only under certain conditions, e.g. full power
    • 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
    • F02M7/00—Carburettors with means for influencing, e.g. enriching or keeping constant, fuel/air ratio of charge under varying conditions
    • F02M7/12—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves
    • F02M7/18—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves with means for controlling cross-sectional area of fuel-metering orifice
    • F02M7/20—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves with means for controlling cross-sectional area of fuel-metering orifice operated automatically, e.g. dependent on altitude

Definitions

  • the object of the present invention is to provide a carburetor in which is provided means for correcting the mixing ratio of the mixture so as to meet the demand of the engine during the high r.p.m. region of said engine with the throttle valve being slightly open (light load), by feeding auxiliary fuel to the engine, and thereby to eliminate the disadvantage set forth above.
  • an auxiliary fuel injection nozzle of an auxiliary fuel feed means is provided adjacent the throttle valve at a location which will be upstream of the throttle valve when said throttle valve is in a fully closed position and downstream of the throttle valve when said throttle valve is in a slightly opened position.
  • Valve means is also provided to permit a fuel supply to said nozzle when the manifold vacuum pressure downstream of said thorttle valve reaches a value greater than a set value. Fuel is injected'from said auxiliary fuel injection nozzle when the throttle valve is oened to a certain degree and the manifold vacuum pressure is higher than the set value, whereby the intake mixture of a mixing ratio suitable for such operating condition of the engine can be obtained.
  • FIG. 1 is a cross-sectional view of an embodiment of the carburetor according to the present invention which is provided with auxiliary fuel feed means;
  • FIG. 2 is graph showing the relationship between the engine r.p.m. and the fuel flow, using the manifold vacuum pressure as a parameter.
  • a two stage dual barrel type carburetor has an auxiliary fuel feed device on a primary barrel 1.
  • the drawings show a two stage dual barrel type carburetor, since the barrel of an ordinary one stage carburetor corresponds to the primary barrel of such a two stage dual barrel type carburetor, the present invention can be practiced by providing the auxiliary fuel feed device on the barrel of the ordinary one stage carburetor.
  • the primary barrel 1 comprises a choke valve 2, a Venturi 3, a main fuel nozzle 4, a butterfly throttle valve 5, and an idling fuel port 6a and a slow port 6b.
  • a secondary barrel 7 is provided with a Venturi 8, a main fuel nozzle 9, a throttle valve 10 and a slow 11 located slightly upstream of a fully closed position of said throttle valve 10.
  • the slow port Ill is connected with a low speed fuel passage 12 formed in the side wall of the barrel 7.
  • auxiliary fuel injection nozzle 13 In the primary barrel 1 is formed an auxiliary fuel injection nozzle 13 adjacent the throttle valve 5 at a location which will upstream of the throttle valve 5 when said throttle valve is in a fully closed position and downstream of the throttle valve 5 when said throttle valve is in a slightly opened position.
  • the auxiliary fuel injection nozzle 13 communicates through a jet l4 and an on-off valve 15 with fuel chamber 17 the wall of which is partially constituted by a diaphragm l6.
  • Auxiliary fuel is supplied from the air bled, low speed fuel passage 12 in the secondary barrel through a branched passage 18 into the fuel chamber 17.
  • a vacuum chamber 19 which communicates through a vacuum passage 20 with an inlet passage downstream of the throttle valve 5 and including the inlet manifold of the engine, to take the manifold vacuum pressure therefrom.
  • the on-off valve 15 has a valve body 22 connected to the diaphragm 16. The valve body 22 is urged by a spring 21 into mating engagement with avalve seat 23 to shut down the auxiliary fuel supply to the injection nozzle 13. The arrangement is such that the on-off valve 15 will be opened when the vacuum pressure introduced into the vacuum chamber 19 through the vacuum passage 20 reaches a value greater than a set value.
  • the manifold vacuum pressure is extremely high when the engine is in the idling operation or the engine brake is in effect, with the throttle valve 5 being fully closed. In this case, therefore, the valve body 22 is disengaged from the valve seat 23 under the effect of the vacuum pressure acting in the vacuum chamber 19 through the vacuum passage 20.
  • the auxiliary fuel injection nozzle 13 is located upstream of the throttle valve 5, the manifold vacuum pressure does not act at the injection nozzle 13 and hence auxiliary fuel is not injected from said injection nozzle.
  • the auxiliary fuel injection nozzle l3 is located downstream of the throttle valve 5.
  • idling speed for example 1,000 to 2,000 r.p.m.
  • the set value for example 1,000 to 2,000 r.p.m.
  • the injection nozzle 13 is opened by way of the diaphragm l6 and thus auxiliary fuel is sucked into the intake mixture to be mixed therewith. Namely, a mixture of a mixing ratio suitable for the high speed operation of the engine with the throttle valve being slightly open can be obtained with high combustion efficiency.
  • auxiliary fuel is fed only when the engine is in the so-called light-load, high speed operation wherein the throttle valve 5 is in the slightly opened position and the manifold vacuum pressure is higher than the set value, as in the case when the automobile is driven on a slow descending slope with a slight pressure being applied to the accelerator pedal.
  • FIG. 2 shows the relationship between the engine rpm. and the adequate fuel flow when the manifold vacuum pressure is -500, -400 and -300 mmI-Ig which pressures are adjusted by controlling the opening degree of the throttle valve.
  • the solid curves represent the characteristic of the subject carburetor provided with the auxiliary fuel feed device and the dotted curves represent the characteristic of buretor and the conventional carburetor (the curves of both carburetors are exactly overlapped in the chart).
  • the degree of opening of the throttle valve is small (e.g., in the case of the manifold vacuum pressure being -400 or -500 mmHg in FIG.
  • the fuel is supplied to the auxiliary fuel injection nozzle through the low speed fuel passage 12 formed in the wall of the secondary barrel, it should be understood that the fuel may be supplied to said injection nozzle directly from the float chamber or the main fuel passage.
  • the fuel passage conncting the auxiliary fuel injection nozzle with the fuel source is preferably provided independently from a passage which supplies fuel to the idling fuel port or the slow port, so that the idling operation of the engine is not disturbed by the auxiliary fuel supplied to the auxiliary fuel injection nozzle.
  • the on-off valve 15 in the embodiment described may be replaced by a diaphragm switch which operates upon sensing the manifold vacuum pressure and a solenoid valve which opens and closes a passage leading to the auxiliary fuel injection nozzle.
  • a carburetor including at least one barrel having a first passage therethrough, a main fuel nozzle, a Venturi, an idling fuel port and a throttle valve for controlling a supply of intake mixture to an engine wherein the improvement comprises:
  • auxiliary fuel injection nozzle open to said first passage, said injection nozzle being located at a position which is upstream of said throttle valve when said throttle valve is in a closed position and which is downstream of said throttle valve when said throttle valve is in a slightly open position;
  • valve means connected to said second fuel passage for opening and closing said second fuel passage, said valve means including means responsive to the manifold vacuum pressure downstream of said throttle valve for opening said second fuel passage when the manifold vacuum pressure exceeds a predetermined value, said second fuel passage being open to allow auxiliary fuel to be added to the intake mixture when the engine is in a relatively high speed operation with the throttle valve slightly open.
  • valve means comprises a vacuum chamber having a diaphragm as one wall, a third vacuum passage connected to said vacuum chamber for introducing the manifold vacuum pressure into said vacuum chamber, a valve body secured to said diaphragm and adapted to open and close said second fuel passage incident to movement of said diaphragm, and a spring urging said valve body into a closed position.
  • a carburetor according to claim 1 wherein said second fuel passage connecting said auxiliary fuel inpendently from a fuel passage leading to said idling fuel port.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Control Of The Air-Fuel Ratio Of Carburetors (AREA)
US00131165A 1970-04-16 1971-04-05 Carburetor provided with auxiliary fuel feed means Expired - Lifetime US3761063A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3694470 1970-04-16

Publications (1)

Publication Number Publication Date
US3761063A true US3761063A (en) 1973-09-25

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ID=12483848

Family Applications (1)

Application Number Title Priority Date Filing Date
US00131165A Expired - Lifetime US3761063A (en) 1970-04-16 1971-04-05 Carburetor provided with auxiliary fuel feed means

Country Status (3)

Country Link
US (1) US3761063A (en, 2012)
DE (1) DE2118095B2 (en, 2012)
FR (1) FR2089802A5 (en, 2012)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3942493A (en) * 1972-09-22 1976-03-09 Robert Bosch Gmbh Fuel metering system
US3994268A (en) * 1973-10-15 1976-11-30 Honda Giken Kogyo Kabushiki Kaisha Internal combustion engine
US4117812A (en) * 1976-01-17 1978-10-03 Honda Giken Kogyo Kabushiki Kaisha Auxiliary fuel feed and timing control system for internal combustion engines
US4198356A (en) * 1978-05-29 1980-04-15 Toyota Jidosha Kogyo Kabushiki Kaisha Control system for secondary transfer port in dual carburetor
US4768494A (en) * 1987-09-09 1988-09-06 Brunswick Corporation Idling system for multi-cylinder two-stroke engine
US6247681B1 (en) * 1995-02-10 2001-06-19 Andreas Stihl Ag & Co. Carburetor for an internal combustion engine of a hand-held working tool

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4108123A (en) * 1976-07-30 1978-08-22 Toyota Jidosha Kogyo Kabushiki Kaisha Carburetor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3167599A (en) * 1962-09-28 1965-01-26 Acf Ind Inc Carburetor
US3333833A (en) * 1965-03-29 1967-08-01 Bendix Corp Carburetor
US3554173A (en) * 1968-03-30 1971-01-12 Nissan Motor Apparatus for reducing hydrocarbon content of engine exhaust gases during decelaration of automobile
US3588058A (en) * 1968-12-23 1971-06-28 Alvin S Lucas Power valve arrangement

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3167599A (en) * 1962-09-28 1965-01-26 Acf Ind Inc Carburetor
US3333833A (en) * 1965-03-29 1967-08-01 Bendix Corp Carburetor
US3554173A (en) * 1968-03-30 1971-01-12 Nissan Motor Apparatus for reducing hydrocarbon content of engine exhaust gases during decelaration of automobile
US3588058A (en) * 1968-12-23 1971-06-28 Alvin S Lucas Power valve arrangement

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3942493A (en) * 1972-09-22 1976-03-09 Robert Bosch Gmbh Fuel metering system
US3994268A (en) * 1973-10-15 1976-11-30 Honda Giken Kogyo Kabushiki Kaisha Internal combustion engine
US4117812A (en) * 1976-01-17 1978-10-03 Honda Giken Kogyo Kabushiki Kaisha Auxiliary fuel feed and timing control system for internal combustion engines
US4198356A (en) * 1978-05-29 1980-04-15 Toyota Jidosha Kogyo Kabushiki Kaisha Control system for secondary transfer port in dual carburetor
US4768494A (en) * 1987-09-09 1988-09-06 Brunswick Corporation Idling system for multi-cylinder two-stroke engine
US6247681B1 (en) * 1995-02-10 2001-06-19 Andreas Stihl Ag & Co. Carburetor for an internal combustion engine of a hand-held working tool

Also Published As

Publication number Publication date
DE2118095A1 (de) 1971-11-04
FR2089802A5 (en, 2012) 1972-01-07
DE2118095C3 (en, 2012) 1978-07-13
DE2118095B2 (de) 1977-11-17

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