US3878271A - Device for feeding the air-fuel mixture to an internal combustion engine during idling - Google Patents

Device for feeding the air-fuel mixture to an internal combustion engine during idling Download PDF

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Publication number
US3878271A
US3878271A US361031A US36103173A US3878271A US 3878271 A US3878271 A US 3878271A US 361031 A US361031 A US 361031A US 36103173 A US36103173 A US 36103173A US 3878271 A US3878271 A US 3878271A
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United States
Prior art keywords
engine
throttle
area
feeding
air
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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
US361031A
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English (en)
Inventor
Giampaolo Garcea
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.)
Fiat Auto SpA
Original Assignee
Alfa Romeo SpA
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Filing date
Publication date
Priority claimed from IT2449172A external-priority patent/IT957000B/it
Priority claimed from IT3301872A external-priority patent/IT971965B/it
Priority claimed from IT2118373A external-priority patent/IT981116B/it
Application filed by Alfa Romeo SpA filed Critical Alfa Romeo SpA
Application granted granted Critical
Publication of US3878271A publication Critical patent/US3878271A/en
Assigned to ALFA LANCIA S.P.A., A CORP. OF ITALY reassignment ALFA LANCIA S.P.A., A CORP. OF ITALY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ALFA ROMEO S.P.A.
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
    • F02M3/00—Idling devices for carburettors
    • F02M3/08—Other details of idling devices
    • F02M3/12—Passageway systems
    • 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
    • F02M7/10—Other installations, without moving parts, for influencing fuel/air ratio, e.g. electrical means

Definitions

  • the device is constituted by a chamber communicating with the atmosphere, the float chamber of the carburettor and the engine intake duct downstream of the throttle, and it comprises an additional chamber which communicates with the atmosphere and with the intake duct of the engine, downstream of the throttle, the communication with the intake duct being manually adjustable; the additional chamber, in addition, communicates with the first named chamber through a calibrated hole.
  • feed of the mixture to the air-fuel cylinders takes place in that, through the minimum opening of the throttle a certain volume of air is drawn and, in parallel with this volume of air also a certain volume of premixture is drawn, that is, of very rich mixture; the volume of air drawn in is thus dependent upon said volumes, on the 1 other hand the strength of the mixture drawn by the cylinders is dependent upon the values of said volumes and the strength of the premixture.
  • lt is recalled that, in fact, in the conventional carburettors when idling, there is no dispensing of fuel in corresponding with the main system" as formed by the choke and the relative calibrated holes for delivering fuel and air.
  • Said premixture rate of flow for idling is drawn through a port whose opening is adjusted by an idling system comprising an emulsion chamber fed through a calibrated hole for fuel and through a calibrated hole for air; the strength of the premixture is dependent upon the sizes of these calibrated holes, and the strength remains constant as the rate of flow of the premixture is varied, both as a result of the variation of the negative pressure prevailing in the intake duct and of a variation of the cross-sectional area of the above mentioned adjustable port.
  • the adjustment operation for example in the sense of increasing the rate of flow of the mixture, cannot be performed by only increasing (by means of the specially provided screw) the above cited adjustable port surface since, concurrently, the strength of the total mixture is varied in the sense of strengthening" it;
  • the device comprises a first cavity equipped with at least a calibrated hole which establishes communication between the cavity and the atmosphere,'with a calibrated hole which establishes a communication between the cavity and the usual carburettor float chamber and with a calibrated hole which establishes a communication between the cavity and the intake duct of the engine downstream of said throttle, and it also comprises a second cavity equipped with a calibrated hole which establishes a communication between the second cavity and the atmosphere and with a manually adjustable port which establishes a communication between the second aforesaid cavity and the intake duct of the engine downstream of said throttle, the first and the second cavity being also mutually in communication through a further calibrated hole.
  • FIG. 1 diagrammatically shows, by way of example, the idling system of a carburettor, according to the invention
  • FIG. 2 is a graph which shows its operation.
  • Numeral 10 generally indicates the carburettor of an internal combustion engine; there can be seen intake duct 11 with its Venturi l2, throttle l3 and constant level float chamber 14; at 15 and 16 are shown the connection flanges for the air filter and the engine head.
  • the drawing does not show conventional details which are of no interest to this invention, such as the main ducts for the mixture which reaches the choke and the relevant air and fuel jets.
  • the throttle 13 is fastened to the shaft 17 which is supported for rotation in the duct 11 and is mechanically connected to the accelerator pedal (not shown) of the vehicle.
  • the shaft 17 is also integral with lever 18 which, as the accelerator pedal is released, abuts the end of stroke screw 19, which defines the minimum opening position of the throttle l3.
  • Numeral 20 indicates the idling jet, that is, the calibrated hole through which the fuel emerges during engine running with the throttle in the maximum closure position and 21 indicates the calibrated hole through which the relative emulsifying air comes from duct 22 which is in parallel with respect to duct 11.
  • the duct 23 which feeds the engine with the air and fuel premixture during idling is in communication with the duct 11 through calibrated hole 24, placed downstream of the throttle 13: in the duct 11, upstream of the throttle, open also the usual progression holes, shown at 25 and 26, with which carburettors are generally equipped.
  • the chamber 27 is in communication with the duct 23 through calibrated hole 30 and a hole 31 opens into chamber 27 and the duct 1 1 downstream of the throttle 13.
  • the device according to the present invention se 5 to remove the intricacy and difficulties of such an 0 eration, so that the operator is requi'red to act on a single adjustment member only (for example an adjustable screw) in order to obtain the desired rate of rotation whereas the mixture strength is in no way altered by the manipulation thereof.
  • a single adjustment member for example an adjustable screw
  • the ratio of the cross-sectional area of the hole 28 and the cross-sectional area of the hole 31 is chosen to be lower than the ratio of the areas of the air intake holes in the duct 23 and the area of the hole 24 through which the premixture emerges, also when the cross-sectional area of the hole 31 is adjusted to its lowest value (during idle running air enters the duct 23 not only through the calibrated hole 21 but also through the progression holes 25 and 26); inasmuch as the conditions of intake and outlet pressure are the same. the negative pressure which is established within the chamber 27 is lower than that prevailing in the duct 23. so that through the hole 30 there is a fluid flow which depends on the setting of the screw 32.
  • the negative pressure in the duct 23 is not varied even though the negative pressure magnitude in the chamber 27 is increased; thus the flow of fuel through the jet 20 does not vary; but the air which is drawn by the engine as a total is increased due to the increase of the flow passage area 31; thus the mixture which is drawn by the engine as a total is leaner.
  • the negative pressure in the duct 23 is always equal to that of the chamber 27 and is increased concurrently therewith; the ratio of flow of air drawn through the ports (communicating with the atmosphere) 21, 25, 26 and 28 is a function of said negative pressure only.
  • the rate of flow of fuel drawn through the port 20 is also a function of said negative pressure only.
  • the lower plot of FIG. 2 shows the variations of the rate of flow Q of the mixture as totally drawn by the engine, as a function of the area S, of the port 31, for different values (expressed in square mms) of the area S of the calibrated hole 30.
  • the values of the abscissae are referred to the value S, of the port 31 which corresponds to the intermediate position of the screw 32 and those shown on the ordinates are referred to the value 0 of the rate of flow of the drawn in mixture, still with the screw 32 in the intermediate position.
  • the upper plot shows curves which show, still as a function of the 5 /8 ratio, the variation of the mixture ratio A/F for different values (expressed in sq.mms) of the cross-sectional area S of the hole 30.
  • the plot thus confirms the possibility of obtaining that which is desired.
  • the strength of the mixture as totally drawn in by the engine remains virtually constant for variations of the air rate of flow (as great as :t 15 percent) obtained by acting only upon the screw 32 which determines the size of the port 31. Practical tests both on the carburettor test bench and on the engine have then confirmed the validity of the theoretical calculations.
  • a carburettor for an internal combustion engine and of the type essentially comprising at least a main system for feeding and forming a fuel/air mixture aspirated by the engine on operating at medium and high outputs, and at least one additional feeding system for the idling and accelerating operation for feeding and forming a fuel/air mixture aspirated by the engine onoperating at zero and low outputs, a throttle for controlling the feeding of the engine, the output delivered by the engine being dependent on the position of said throttle.
  • said idling and accelerating system comprising a first and a second cavity intercommunicating with each other through a calibrated port, the first cavity being in communication through a first calibrated hole with a fuel feeding duct, through at least one second calibrated hole with the ambient atmosphere and through at least one third calibrated hole with the engine inlet duct downstream of the throttle, the second cavity being in communication through at least one fourth calibrated hole with the ambient atmosphere and at least through a manually adjustable port with the engine inlet duct downstream of the throttle, the ratio between the area of said second calibrated hole and the area of said third calibrated hole being correlated with the second cavity is such that, during the adjustment of the idling operation of the engine, on varying the section of the adjustable port, while the air passage area left uncovered by the throttle is unchanged the flow rate of the air mixed with fuel passing from the first to the second cavity varies so that the fuel/air ratio of the total mixture aspirated by the engine remains constant.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
  • Control Of The Air-Fuel Ratio Of Carburetors (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
US361031A 1972-05-17 1973-05-17 Device for feeding the air-fuel mixture to an internal combustion engine during idling Expired - Lifetime US3878271A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IT2449172A IT957000B (it) 1972-05-17 1972-05-17 Dispositivo per l alimentazione di miscela ad un motore a scoppio nel funzionamento al minimo
IT3301872A IT971965B (it) 1972-12-15 1972-12-15 Perfezionamento ai carburatori per motori a combustione interna
IT2118373A IT981116B (it) 1973-03-05 1973-03-05 Dispositivo di carburatore del la miscela per il funzionamento al minino in progressione di un motore a scoppio

Publications (1)

Publication Number Publication Date
US3878271A true US3878271A (en) 1975-04-15

Family

ID=27273144

Family Applications (3)

Application Number Title Priority Date Filing Date
US361031A Expired - Lifetime US3878271A (en) 1972-05-17 1973-05-17 Device for feeding the air-fuel mixture to an internal combustion engine during idling
US05/424,608 Expired - Lifetime US3963808A (en) 1972-05-17 1973-12-13 Carburetors for internal combustion engines
US05/447,770 Expired - Lifetime US3937766A (en) 1972-05-17 1974-03-04 Mixture carburation device for the operation in idling conditions in progression of an internal combustion engine

Family Applications After (2)

Application Number Title Priority Date Filing Date
US05/424,608 Expired - Lifetime US3963808A (en) 1972-05-17 1973-12-13 Carburetors for internal combustion engines
US05/447,770 Expired - Lifetime US3937766A (en) 1972-05-17 1974-03-04 Mixture carburation device for the operation in idling conditions in progression of an internal combustion engine

Country Status (4)

Country Link
US (3) US3878271A (en:Method)
DE (1) DE2325045C2 (en:Method)
FR (1) FR2220684B1 (en:Method)
GB (2) GB1446898A (en:Method)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3931372A (en) * 1973-11-21 1976-01-06 Societe Industrielle De Brevets Et D'etudes S.I.B.E. Carburettors for internal combustion engines
US4007237A (en) * 1975-04-19 1977-02-08 Toyota Jidosha Kogyo Kabushiki Kaisha Compensation apparatus for carburetor
DE2855683A1 (de) * 1978-12-22 1980-06-26 Pierburg Gmbh & Co Kg Vergaser fuer brennkraftmaschinen
US4217313A (en) * 1978-04-21 1980-08-12 Dmitrievsky Anatoly V Device for reducing noxious emissions from carburetor internal combustion engines
DE3238171A1 (de) * 1981-10-31 1983-05-05 Aisan Kogyo K.K., Obu, Aichi Vergaser fuer motoren mit innerer verbrennung
US4931226A (en) * 1989-03-01 1990-06-05 Shinagawa Diecasting Co., Ltd. Charge forming apparatus
DE4409887A1 (de) * 1994-03-22 1995-09-28 Stihl Maschf Andreas Membranvergaser für einen Verbrennungsmotor

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4379096A (en) * 1981-11-24 1983-04-05 Suzuki Motor Co., Ltd. Compound carburetor
CA1212283A (en) * 1982-12-27 1986-10-07 Gordon C. Slattery Internal combustion engine with air-fuel mixture heating
US4534333A (en) * 1982-12-27 1985-08-13 Brunswick Corporation Internal combustion engine with air-fuel mixture heating
DE3339714C2 (de) * 1983-11-03 1999-09-30 Stihl Maschf Andreas Leerlaufsystem für einen Membranvergaser
IT1224457B (it) * 1988-09-30 1990-10-04 Marco Morini Gruppo per l'alimentazione di un motore a carburazione in condizioni particolari di funzionamento
DE3901627C3 (de) * 1989-01-20 2000-06-29 Walbro Gmbh Vergaser mit einer Einrichtung zur Leerlaufeinstellung
US6499726B2 (en) 1999-11-04 2002-12-31 Tecumseh Products Company Engine having carburetor with bridge circuit
US8333366B2 (en) * 2010-03-08 2012-12-18 Briggs & Stratton Corporation Carburetor including one-piece fuel-metering insert

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2689115A (en) * 1951-03-23 1954-09-14 Gen Motors Corp Carburetor
US3100236A (en) * 1960-03-24 1963-08-06 Acf Ind Inc Carburetor
US3350072A (en) * 1966-05-27 1967-10-31 Ford Motor Co Air valve carburetor
US3374991A (en) * 1965-03-12 1968-03-26 Walker Brooks Carburetor
US3608874A (en) * 1968-03-01 1971-09-28 Volkswagenwerk Ag Carburetor for internal combustion engines
US3625492A (en) * 1969-04-16 1971-12-07 Briggs & Stratton Corp Carburetor for small internal combustion engine having automatic choke control

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3077341A (en) * 1960-04-01 1963-02-12 Acf Ind Inc Carburetor
US3283751A (en) * 1963-06-28 1966-11-08 Inst Khim Fysiki Internal combustion engine with jet ignition of a non-uniformly distributed working mixture from a precombustion chamber cut-off by the piston
US3313532A (en) * 1964-09-08 1967-04-11 Acf Ind Inc Anti-smog device
US3382856A (en) * 1965-10-22 1968-05-14 Ford Motor Co Engine fuel induction system
US3408054A (en) * 1967-07-26 1968-10-29 Walker Brooks Carburetor
FR1547734A (fr) * 1967-10-19 1968-11-29 Sibe Perfectionnements apportés aux carburateurs pour moteurs à combustion interne
DE1576458A1 (de) * 1967-11-30 1970-06-18 Audi Nsu Auto Union Ag Regelungsvorrichtung fuer den Leerlauf von Brennkraftmaschinen mit Vergaser
GB1242288A (en) * 1968-03-30 1971-08-11 Nissan Motor Carburetors for internal combustion engines
US3711069A (en) * 1969-08-15 1973-01-16 Ford Motor Co High velocity carburetor idle system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2689115A (en) * 1951-03-23 1954-09-14 Gen Motors Corp Carburetor
US3100236A (en) * 1960-03-24 1963-08-06 Acf Ind Inc Carburetor
US3374991A (en) * 1965-03-12 1968-03-26 Walker Brooks Carburetor
US3350072A (en) * 1966-05-27 1967-10-31 Ford Motor Co Air valve carburetor
US3608874A (en) * 1968-03-01 1971-09-28 Volkswagenwerk Ag Carburetor for internal combustion engines
US3625492A (en) * 1969-04-16 1971-12-07 Briggs & Stratton Corp Carburetor for small internal combustion engine having automatic choke control

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3931372A (en) * 1973-11-21 1976-01-06 Societe Industrielle De Brevets Et D'etudes S.I.B.E. Carburettors for internal combustion engines
US4007237A (en) * 1975-04-19 1977-02-08 Toyota Jidosha Kogyo Kabushiki Kaisha Compensation apparatus for carburetor
US4217313A (en) * 1978-04-21 1980-08-12 Dmitrievsky Anatoly V Device for reducing noxious emissions from carburetor internal combustion engines
DE2855683A1 (de) * 1978-12-22 1980-06-26 Pierburg Gmbh & Co Kg Vergaser fuer brennkraftmaschinen
US4283354A (en) * 1978-12-22 1981-08-11 Pierburg Gmbh & Co. Kg Carburetor for internal-combustion engines
DE3238171A1 (de) * 1981-10-31 1983-05-05 Aisan Kogyo K.K., Obu, Aichi Vergaser fuer motoren mit innerer verbrennung
US4931226A (en) * 1989-03-01 1990-06-05 Shinagawa Diecasting Co., Ltd. Charge forming apparatus
DE4409887A1 (de) * 1994-03-22 1995-09-28 Stihl Maschf Andreas Membranvergaser für einen Verbrennungsmotor

Also Published As

Publication number Publication date
DE2325045A1 (de) 1973-11-29
GB1462663A (en) 1977-01-26
FR2220684A1 (en:Method) 1974-10-04
DE2325045C2 (de) 1985-07-25
FR2220684B1 (en:Method) 1979-01-26
US3937766A (en) 1976-02-10
US3963808A (en) 1976-06-15
GB1446898A (en) 1976-08-18

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Legal Events

Date Code Title Description
AS Assignment

Owner name: ALFA LANCIA S.P.A., ARESE, MILAN, ITALY, A CORP. O

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ALFA ROMEO S.P.A.;REEL/FRAME:004831/0252

Effective date: 19870930

Owner name: ALFA LANCIA S.P.A., A CORP. OF ITALY,ITALY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ALFA ROMEO S.P.A.;REEL/FRAME:004831/0252

Effective date: 19870930