US3875267A - Carburetor float - Google Patents

Carburetor float Download PDF

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Publication number
US3875267A
US3875267A US424082A US42408273A US3875267A US 3875267 A US3875267 A US 3875267A US 424082 A US424082 A US 424082A US 42408273 A US42408273 A US 42408273A US 3875267 A US3875267 A US 3875267A
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US
United States
Prior art keywords
float
fuel
chamber
upper sections
liquid
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
US424082A
Other languages
English (en)
Inventor
Chichitada Seki
Takashi Hisatomi
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.)
Nissan Motor Co Ltd
Original Assignee
Nissan Motor 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 Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Application granted granted Critical
Publication of US3875267A publication Critical patent/US3875267A/en
Anticipated expiration legal-status Critical
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
    • F02M5/00—Float-controlled apparatus for maintaining a constant fuel level
    • F02M5/12—Other details, e.g. floats, valves, setting devices or tools
    • F02M5/16—Floats
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S261/00—Gas and liquid contact apparatus
    • Y10S261/50—Surge prevention in carburetors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7287—Liquid level responsive or maintaining systems
    • Y10T137/7358—By float controlled valve
    • Y10T137/742—In separate communicating float chamber
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7287—Liquid level responsive or maintaining systems
    • Y10T137/7358—By float controlled valve
    • Y10T137/7439—Float arm operated valve
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7287—Liquid level responsive or maintaining systems
    • Y10T137/7358—By float controlled valve
    • Y10T137/7439—Float arm operated valve
    • Y10T137/7465—Assembly mounted on and having reciprocating valve element coaxial with inlet pipe
    • Y10T137/7472—Vertical inlet riser

Definitions

  • the present invention relates to a carburetor float for an internal combustion engine, and more particularly to a carburetor float of a particular shape suitable for holding a needle valve in a closed position even if the carburetor or fuel surface is tilted forward or backward to prevent overfllling of the carburetor float chamber.
  • a float system of an internal combustion engine carburetor generally includes a float bowl or chamber and float and needle valve members accommodated in the float bowl to maintain a constant desired level of fuel.
  • the float chamber is in communication with the atmosphere through an air vent and provided with a fuel outlet and a fuel inlet which is controlled by the needle valve.
  • the needle valve operates in cooperation with the float which is supported on a free end of a hinged lever. More particularly, an upward moment resulting from floatation of the float is transmitted to the needle valve for closing the same, to control the flow of fuel into the float chamber through the fuel inlet to maintain the constant desired fuel level.
  • a float of such a shape presents a difficulty in that the fuel inlet is erroneously opened due to a reduction in buoyant force acting on the float when the float chamber or fuel surface is inclined in a particular direction, as in acceleration, hillclimbing and turning of the vehicle. This causes the float chamber to overfill, and fuel may spurt out through the air vent and the main nozzle inviting acceleration failure or engine stoppage due to over supply of an air-fuel mixture to the engine.
  • FIG. 1 is a fragmentary vertical sectional view of an existing carburetor float system
  • FIG. 2 is a vertical sectional view of the inner arrangement of the float chamber of the existing carburetor float system shown in FIG. 1',
  • FIGS. 3 and 4 are views similar to FIGS. 1 and 2, respectively, but show the surface of the fuel as inclined with respect to the float chamber;
  • FIG. 5 is a vertical sectional view of a float chamber incorporating a carburetor float embodying the present invention
  • FIG. 6 is a horizontal section along a line A A of FIG. 5;
  • FIGS. 7 and 8 are vertical sectional views of the float chamber of FIG. 5 with the surface of the fuel inclined in opposite directions with respect to the float chamber;
  • FIG. 9 is a graph showing the variation of moment employing a float of the invention and a conventional float in dependence on the angle of inclination of the fuel surface.
  • FIGS. 10 and 11 are elevational views showing modified configurations of floats according to the invention.
  • an existing carburetor float system which includes a float chamber II which communicates with the atmosphere through an air vent 12.
  • the float chamber 11 is provided with a fuel outlet 13 for supplying fuel into the induction passage 14 of a carburetor of the engine through a main nozzle 15 which opens into a venturi portion 16 upstream of a throttle valve 17.
  • the float chamber 11 is further provided with a fuel inlet 18 for receiving a fuel through a fuel supply passage 19 feeding thereinto.
  • a numeral 10 represents the surface of the fuel in the float chamber 11.
  • the amount of fuel which flows into the float chamber 11 is controlled by a fuel inlet valve or needle valve 20 which is supported on a hinge lever 21.
  • the hinge lever 21 is pivotally supported at one end thereof on a normally horizontal pin 22.
  • the opposite free end of the hinge lever 21 is connected to a float 23 in such a manner that upward moment produced by buoyant force acting on the float 23 is transmitted to the needle valve 20 by means such as shown to cause the same to close the fuel inlet 18 to maintain a constant fuel level in the float chamber 11.
  • Fuel from the main nozzle 15 is sucked into the engine at a rate corresponding to the volume of air flowing through the venturi portion 16 in accordance with the throttle 17 position.
  • the needle valve 20 is opened due to a reduction in the buoyant force acting on the float 23 to introduce more fuel into the float chamber 11, thus maintaining the surface level of the fuel constant. It will be noticed that the float 23 is swingable in a normally vertical plane about the pin 22.
  • a conventional carburetor float system employs a float of a simple rectangular parallelepiped shape as shown in FIG. 4.
  • the surface 10 of the fuel in the float chamber 11 is inclined downward away from the pin 22 as shown in FIG. 3 or upward toward the pin 22 as shown in FIG. 4.
  • the needle valve 20 is kept closed by increased buoyant force on the float 23.
  • the needle valve 20 is erroneously opened, allowing fuel to flow into the float chamber 11 and overfill it. This causes an excessively enriched airfuel mixture leading to acceleration failure and engine stoppage, both with fixed venturi carburetors and variable venturi carburetors.
  • the float 24 has a downwardly extending lower section 25 and two symmetrical upper sections 26 and 27. As show. the profiles of the lower and upper sections 25, and 26 and 27 are respectively triangular and trapezoidal. The upper sections 26 and 27 are spaced along the axis of the lever 21.
  • the float 24 is formed of a plastic material such as foamed styrol having a specific gravity of about 0.2. As shown particularly in FIG. 5, the float 24 normally floats on the fuel or other liquid with the lower section 25 below the surface 10, and the upper sections 26 and 27 above the surface 10, one of the upper sections 26 and 27 is connected to the free end ofthe hinge lever 21 in the usual manner to control the position of the needle valve 20.
  • the force with which the needle valve 20 is pressed against its valve seat with a normal volume of fuel in the float chamber 11 may be expressed in terms of a differential moment between upward and downward moments imposed on the hinge lever 21 by the following equation, with reference to FIGS. 4. 5, 7 and 8:
  • Differential moment (7a) (Clockwise moment counterclockwise moment)/- (counter-clockwise moment) X 100
  • the clockwise moment is that imparted to the lever 21 by the buoyant force acting on the float 23 or 24 and the counter-clockwise moment is that imparted to the lever 21 by gravity and the pressure of fuel in the passage l9 acting on the needle valve 20.
  • the differential moment thus represents the percentage by which the forces acting to close the needle valve 20 are greater than those acting to open the needle valve 20.
  • This differential moment is preferred to be within a range of 20 to 40% in consideration of vibration of the surface 10 of the fuel within the float chamber 11, irregularities in performance of individual carburetor float systems, or fluctuations of the fuel pressure in the fuel supply passage l9.
  • the differential moment becomes too large when the fuel surface I0 is inclined as shown in FIG. 3, as indicated by a solid line 28 in FIG. 9.
  • the differential moment becomes negative and the needle valve 20 is opened, allowing fuel to flow into the float chamber 11 to overfill it.
  • the differential moment is maintained constant within the range of 20 to 40% due to the shape of the float 24, even when the fuel surface 10 within the float chamber 11 is inclined in either direction, as indicated by a broken line 29 in FIG. 9.
  • a carburetor float 24 of the present invention can hold the needle valve 20 in its closed position with sufficient force, irrespective of the inclination of the surface 10 of fuel within the float chamber 11.
  • the float 24 is symmetrical in cross section and size with respect to its vertical axis.
  • the float 24 may be provided in an asymmetric form as particularly shown in FIGS. 10 or 11, taking into consideration the particular shape or size of the float chamber 11 and/or the particular requirements of the weight of the float 24.
  • the floats 24 have lower sections 25 and 25", and upper sections 26' and 27' and 26" and 27", similar to the float 24 employed in the first embodiment shown in FIGS. 5 to 8.
  • the function of the floats 24 with sections of different size is substantially the same as in the first embodiment, and thus a description is not given to avoid repetition.
  • said float having one lower section and two upper sections spaced along the axis of the lever;
  • said lower section being substantially below and said two upper sections being substantially above a predetermined normal level of liquid in the float chamber;
  • a float as claimed in claim I in which said lower section has a substantially triangular profile and said two upper sections have substantially trapezoidal profiles.
  • a float as claimed in claim I in which said lower and said two upper sections have substantially rectangular profiles.

Landscapes

  • 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)
  • Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)
US424082A 1972-12-20 1973-12-12 Carburetor float Expired - Lifetime US3875267A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47127098A JPS4985426A (de) 1972-12-20 1972-12-20

Publications (1)

Publication Number Publication Date
US3875267A true US3875267A (en) 1975-04-01

Family

ID=14951523

Family Applications (1)

Application Number Title Priority Date Filing Date
US424082A Expired - Lifetime US3875267A (en) 1972-12-20 1973-12-12 Carburetor float

Country Status (5)

Country Link
US (1) US3875267A (de)
JP (1) JPS4985426A (de)
DE (1) DE2362699A1 (de)
FR (1) FR2211596B1 (de)
GB (1) GB1426088A (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4371000A (en) * 1980-02-15 1983-02-01 Toyota Jidosha Kogyo Kabushiki Kaisha Anti surge float chamber assembly
US4750515A (en) * 1986-06-19 1988-06-14 H. Ikeuchi & Co., Ltd. Liquid storage tank float valve device
US4861524A (en) * 1987-03-19 1989-08-29 Merck Patent Gesellschaft Mit Beschrankter Haftung Apparatus for producing a gas mixture by the saturation method
AU738611B2 (en) * 1997-09-12 2001-09-20 Mannesmann Vdo Ag Method of producing a float, a fuel-resistant float and a use for pressed together particles produced by extrusion
US6554258B2 (en) * 2000-06-23 2003-04-29 Pow Engineering, Inc. Carburetor float bowl
US6701784B1 (en) * 2003-01-22 2004-03-09 Aeromotive, Inc. Carburetor fuel level management system
US20070013086A1 (en) * 2005-07-11 2007-01-18 Patrick Cooper Quick jet change fuel float bowl
US20190195377A1 (en) * 2017-12-22 2019-06-27 Walbro Llc Float and hinge for a valve
US11225932B2 (en) * 2014-10-07 2022-01-18 K&N Engineering, Inc. Bottom feed fuel bowl

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3128562A1 (de) * 1981-07-18 1983-01-27 Pierburg Gmbh & Co Kg, 4040 Neuss Schwimmer einer schwimmerkammer
JPS60190956U (ja) * 1984-05-29 1985-12-18 日産自動車株式会社 気化器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1186164A (en) * 1913-03-12 1916-06-06 Benjamin Electric Mfg Co Carbureter.
US1995228A (en) * 1933-01-23 1935-03-19 Firm Soc Du Carburateur Blerlo Aircraft carburetor
US3263975A (en) * 1963-12-30 1966-08-02 Ford Motor Co Charge forming device having a constant level device
US3719352A (en) * 1971-11-11 1973-03-06 Ford Motor Co Inertia responsive carburetor fuel flow control means

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1186164A (en) * 1913-03-12 1916-06-06 Benjamin Electric Mfg Co Carbureter.
US1995228A (en) * 1933-01-23 1935-03-19 Firm Soc Du Carburateur Blerlo Aircraft carburetor
US3263975A (en) * 1963-12-30 1966-08-02 Ford Motor Co Charge forming device having a constant level device
US3719352A (en) * 1971-11-11 1973-03-06 Ford Motor Co Inertia responsive carburetor fuel flow control means

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4371000A (en) * 1980-02-15 1983-02-01 Toyota Jidosha Kogyo Kabushiki Kaisha Anti surge float chamber assembly
US4750515A (en) * 1986-06-19 1988-06-14 H. Ikeuchi & Co., Ltd. Liquid storage tank float valve device
US4861524A (en) * 1987-03-19 1989-08-29 Merck Patent Gesellschaft Mit Beschrankter Haftung Apparatus for producing a gas mixture by the saturation method
AU738611B2 (en) * 1997-09-12 2001-09-20 Mannesmann Vdo Ag Method of producing a float, a fuel-resistant float and a use for pressed together particles produced by extrusion
EP1012543B1 (de) * 1997-09-12 2002-11-27 Siemens Aktiengesellschaft Verfahren zum Herstellen eines Schwimmers
US6554258B2 (en) * 2000-06-23 2003-04-29 Pow Engineering, Inc. Carburetor float bowl
US6701784B1 (en) * 2003-01-22 2004-03-09 Aeromotive, Inc. Carburetor fuel level management system
US20070013086A1 (en) * 2005-07-11 2007-01-18 Patrick Cooper Quick jet change fuel float bowl
US7398962B2 (en) * 2005-07-11 2008-07-15 Patrick Cooper Quick jet change fuel float bowl
US11225932B2 (en) * 2014-10-07 2022-01-18 K&N Engineering, Inc. Bottom feed fuel bowl
US11946440B2 (en) 2014-10-07 2024-04-02 K&N Engineering, Inc. Bottom feed fuel bowl
US20190195377A1 (en) * 2017-12-22 2019-06-27 Walbro Llc Float and hinge for a valve
US11274762B2 (en) * 2017-12-22 2022-03-15 Walbro Llc Float and hinge for a valve

Also Published As

Publication number Publication date
DE2362699A1 (de) 1974-07-11
FR2211596A1 (de) 1974-07-19
FR2211596B1 (de) 1978-11-10
GB1426088A (en) 1976-02-25
JPS4985426A (de) 1974-08-16

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