US3779530A - Carburetors - Google Patents

Carburetors Download PDF

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Publication number
US3779530A
US3779530A US00127206A US3779530DA US3779530A US 3779530 A US3779530 A US 3779530A US 00127206 A US00127206 A US 00127206A US 3779530D A US3779530D A US 3779530DA US 3779530 A US3779530 A US 3779530A
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United States
Prior art keywords
throttle valve
passage
valve
carburetor
induction passage
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
US00127206A
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English (en)
Inventor
G Lawrence
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.)
Zenith Carburetter Co Ltd
Original Assignee
Zenith Carburetter 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 Zenith Carburetter Co Ltd filed Critical Zenith Carburetter Co Ltd
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Publication of US3779530A publication Critical patent/US3779530A/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
    • 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
    • F02M7/14—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves with means for controlling cross-sectional area of fuel spray nozzle
    • F02M7/16—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves with means for controlling cross-sectional area of fuel spray nozzle operated automatically, e.g. dependent on exhaust-gas analysis
    • F02M7/17—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves with means for controlling cross-sectional area of fuel spray nozzle operated automatically, e.g. dependent on exhaust-gas analysis by a pneumatically adjustable piston-like element, e.g. constant depression carburettors
    • 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
    • F02M3/09—Valves responsive to engine conditions, e.g. manifold vacuum

Definitions

  • ABSTRACT [30] Forelg Apphcaum? P nomy Data
  • Great Brltam 15,079/70 butterfly throttle valve is provided with an auxiliary Y passage for supplying air directly to the induction pas- [22] l:J.S.CCII.
  • This invention relates to carburetors for internal combustion engines, and, more specifically, to carburetors of the so-called constant depression type, in which there is provided in the induction passage of the carburetor, upstream of the throttle valve, an air valve which is controlled automatically in response to any tendency for the depression in the part of the induction passage, between the throttle valve and the air valve, which part is hereinafter called the mixing chamber, to change, so as to maintain the depression in the said mixing chamber substantially constant.
  • Fuel is supplied to the induction passage of such carburetors through anorifice leading into a throat the area of which is defined by the position of the air valve, the area of the orifice itself being varied by movement of a profiled needle extending through the said orifice and moving to increase the said area as the throat area is increased by movement of the air valve.
  • theadditional air was supplied to the mixing chamber, but the supply of additional air to the mixing chamber has been found to affect adversely both the quality of idling and the response of the carburetor to throttle movement in th range adjacent to the idling position.
  • a carburetor of the constant depression type as herein defined and having a butterfly type throttle valve wherein a further passage provided for supplying air directly 'to the induction passage at a position downstream of the throttle valve when the said throttle valve is in the idling position is so controlled by operation of the throttle valve that the supply of air through said further passage to the induction passage downstream of the throttle valve ceases when the said throttle valve has passed through a small range of movement in the opening direction from said idling position.
  • said further passage opens into the said induction passage at a position adjacent the edge of the throttle valve which moves away from the mixing chamber as the said throttle valve moves from its idling position, the said position of the passage opening being such that, when the throttle valve is in the idling position the said passage opening is on the downstream side of the throttle valve, the edge of the throttle valve passing across the said opening during a small range of movement from said idling position.
  • the edge of the throttle valve is transferred from a position upstream of the passage opening to a position downstream thereof during an angular movement of the throttle valve such that the change in total air flow through the carburetor does not exceed one pound per minute.
  • the passage opening may be a circumferentially extending slot or a circumferentially extending row of holes so that, for a given area of the passage opening, the movement of the throttle valve edge necessary for said-edge to pass across the passage opening is relatively small.
  • the slot or series of holes has a length such that it subtends an angle of not more than 6 at the center of the induction passage.
  • said further passage is controlled by a normally open valve closed by operation of the throttle valve to move it from its idling position.
  • the normally open valve may be coupled mechanically to linkage means for operating the throttle valve or may be closed by a solenoid energized by operation of the throttle valve to move it from the idling position.
  • the normally open valve may be a rotary valve or a needle valve.
  • Adjustable flow controlling means may be provided in said further passage, and said means may comprise a fixed flow restricting device and a variable flow restricting device arranged in parallel.
  • FIG. 1 is a partial longitudinal section of one form of carburetor embodying the invention
  • FIG. 2 is a section on the line 2 2 of FIG. 1;
  • FIG. 3 is a section similar to FIG. 2 but showing a modification
  • FIG. 4 is a partial longitudinal section, similar to FIG. 1, showing another embodiment of the invention.
  • FIG. 5 shows a detail modification of the embodiment shown in FIG. 4; and I FIG. 6 is a partial longitudinal section, similar to FIG.
  • a butterfly type throttle valve 14 mounted in the in. duction passage 11 adjacent-its outlet end 13 is carried by a pivot shaft 15 arranged to be rotated by an operator through a mechanical linkage (not shown) to open and close the said throttle valve.
  • the air valve slide 17 co-operates with the bridge 16 to provide a variable throat at 18, the slide 17 being controlled in the usual manner by differential air pressure acting, in a housing (not shown) on opposite sides of a piston or diaphragm connected to the slide, in such a way that depression in the part of the induction passage between the air valve slide 17 and the throttle valve 14,
  • the mixing chamber 19 tends tocause movement of the slide away from the bridge and increase the area of the throat thereby maintaining the depression in the said mixing chamber 19 substantially constant.
  • a fuel supply orifice 21 opens into the bridge surface and is connected to a float chamber (not shown) containing fuel which is maintained at a constant level by a float-controlled valve, and a profiled needle 22, carried by the air valve slide 17, varies the effective area of the orifice 21 according to the position of the air valve.
  • the connection at 25 may be a circumferentially extending slot 26 as shown in FIG. 2, or a circumferential row of holes 27 as shown in FIG. 3, the slot or row of holes preferably subtending an angle of not more than 6 at the axis of the induction passage.
  • a first passage 33 in the unit 32 connects with the passage 31, a second passage 34 in the unit 32, parallel to the passage 33, is closed at one end and connected at the other end by a passage 35 to the passage 33, and a further passage 36 connecting the passages 33 and 34 is connected intermediate its ends by a passage 37 to the passage 28.
  • a screw plug 38 mounted in a screw-threaded bore aligned with the passage 35 has a tapered end 39 seating in the passage 35 and is formed with intersecting bores 41, 42 providing a fixed flow restriction between the passages 33 and 34, and a second screw plug 43, mounted in a screw-threaded bore 44 aligned with the passage 36, has tapered portions 45 and 46 cooperating respectively with the parts of the passage 36 on opposite sides of the passage 37 to provide a variable restriction of flow between the passages 34 and 37.
  • the actual rate of flow of air through the passages 31, 23 can be approximately determined by selecting the area of the passages 41, 42 in the plug 38, and can be slightly varied in either the increasing or the decreasing senses by moving the plug 43 in or out.
  • the passage 23, instead of being a passage open at all times to the induction passage and traversed by the edge of the throttle valve 14 as the latter opens, has its opening to the induction passage spaced some distance downstream of the throttle valve, at 44a.
  • a rotary valve plug 45a having an L-shaped passage 46a therein, is attached to an arm 47 connected by a link 48 to a throt' tle valve operating arm 49 connected to a throttle control linkage (not shown) the arrangement being such that, when the throttle valve 14 is in the idling position, as shown, the passage 46a in the valve plug connects the passage 23 to the opening 44a, but a small opening movement of the throttle valve rotates the plug a to bring the passage 46a out of register with the passage 23 and opening 44a, thus shutting off the supply of air to the induction passage through the passage 23.
  • FIG. 5 shows an arrangement similar to that of FIG. 4, but in which the valve plug 45a is formed with a slot 51 instead of a passage 46a.
  • the passage 23 leads into a passage 52 opening into the induction passage 11 downstream of the throttle valve 14, the passage 52 being formed with a seating 53 for a needle valve 54 acted on by a solenoid 55 which, when energized, causes the needle valve to engage the seat.
  • a normally open electric switch 56 is operated by an arm 57 fixed to the throttle valve spindle 15 so as to be closed when the throttle valve is moved slightly from the idling position, completing a circuit through the solenoid 55 and a battery 58 to energize the solenoid and so seat the needle valve 54.
  • FIGS. 4, 5 and 6 are substantially identical with that shown in FIG. 1.
  • the influence of the extra air supply is restricted to the idling condition and the condition close to idling, the said extra air supply does not interfere with the main metering characteristics of the carburetor.
  • the plug 43 of the flow restricting unit, or a further flow restricting device in the extra air supply passage, may be controlled by an aneroid capsule or other altitude sensing device to provide automatic fuel/air mixture compensation for changes of altitude at idling speeds.
  • an extra air supply passage may obviate the need for other adjustments to control idling, such as adjustments of the relative positions of the fuel orifice and profiled needle for a given position of the air valve.
  • the air flow in the extra air supply passage may be used to provide a signal to operate a pneumatic ignition retarding capsule of known type.
  • a carburetor comprising a body defining a first induction passage having an upstream end and a downstream end, a throttle valve of the pivoted flat type, including means for pivoting the same in said induction passage, said throttle valve having an idling position in which it is substantially closed, an air valve in said induction passage, said air valve cooperating with a wall of said induction passage to define a throat between said throttle valve and the upstream end of said induction passage, said throttle valve and said air valve defining between them a mixing chamber in said induction passage, means for supplying fuel to said throat, a second passage connected to said induction passage, said second passage being connected, at one end, only to the upstream end of said induction passage and upstream of said air valve and, at the other end, on the downstream side of said throttle valve when said throttle valve is in the idling position so that suction in said induction passage, when the throttle valve is in the idling position, creates air flow through said second passage, means including at least a part of said throttle valve responsive to
  • a carburetor according to claim 1 wherein the edge of said throttle valve is transferred from a position upstream of the other end of said second passage to a position downstream thereof during an angular movement of said throttle valve such that the change in total air flow through the carburetor does not exceed one pound per minute.
  • a carburetor according to claim 1 wherein the passage opening at said other end comprises a circumferentially extending row of holes.
  • a carburetor as claimed in claim 1 in which said second passage opens into said induction passage at a position on a diameter of said throttle valve normal to the axis of said throttle valve where the edgeof said throttle valve moves, as said valve opens, towards the downstream end of said induction passage, and in which said second passage is open to said induction passage at a position which is immediately downstream of said throttle valve edge when said throttle valve is in the idling position, said latter position comprising said eliminating means.
  • said eliminating means comprises a shut-off valve provided in said second passage, operating means for opening and closing said shut-off valve, a control device connected to said throttle valve and means linking said throttle valve control device and said operating means, said control device causing said operating means to open said shut-off valve when said throttle valve is in the idling position and to close said shut-off valve during initial opening of said throttle valve from the idling position.
  • shut off valve is a rotary valve

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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)
  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
US00127206A 1970-03-31 1971-03-23 Carburetors Expired - Lifetime US3779530A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1507970 1970-03-31

Publications (1)

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US3779530A true US3779530A (en) 1973-12-18

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US00127206A Expired - Lifetime US3779530A (en) 1970-03-31 1971-03-23 Carburetors

Country Status (5)

Country Link
US (1) US3779530A (enrdf_load_stackoverflow)
DE (1) DE2114921A1 (enrdf_load_stackoverflow)
FR (1) FR2087947A5 (enrdf_load_stackoverflow)
GB (1) GB1295774A (enrdf_load_stackoverflow)
SE (1) SE362684B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3959417A (en) * 1973-07-14 1976-05-25 Toyota Judosha Kogyo Kabushiki Kaisha Carburetor
US4021513A (en) * 1973-11-07 1977-05-03 The Zenith Carburetor Company Limited Carbureters
US4136139A (en) * 1976-12-16 1979-01-23 Toyota Jidosha Kogyo Kabushiki Kaisha Variable venturi type carburetor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108131218A (zh) * 2017-11-14 2018-06-08 王正富 微风式小排量摩托车化油器

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1722934A (en) * 1923-07-09 1929-07-30 Herbert E Medley Carburetor
US2827269A (en) * 1955-04-25 1958-03-18 Holley Carburetor Co Idle control system
US2996051A (en) * 1960-01-13 1961-08-15 Gen Motors Corp Carburetor
US3147320A (en) * 1961-05-16 1964-09-01 Enginering Res And Applic Ltd Carburetors
US3198498A (en) * 1961-10-09 1965-08-03 Sibe Pressure carburetors
US3198497A (en) * 1961-07-19 1965-08-03 Sibe Carburetors for internal combustion engines
US3278171A (en) * 1963-10-28 1966-10-11 Acf Ind Inc Carburetor
US3295839A (en) * 1964-04-29 1967-01-03 Gen Motors Corp Carburetor idle air bypass arrangement
US3409277A (en) * 1966-06-24 1968-11-05 Acf Ind Inc Metering jet adjustable fuel by-pass
US3455260A (en) * 1965-10-25 1969-07-15 Sibe Carburettors for internal combustion engines

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1722934A (en) * 1923-07-09 1929-07-30 Herbert E Medley Carburetor
US2827269A (en) * 1955-04-25 1958-03-18 Holley Carburetor Co Idle control system
US2996051A (en) * 1960-01-13 1961-08-15 Gen Motors Corp Carburetor
US3147320A (en) * 1961-05-16 1964-09-01 Enginering Res And Applic Ltd Carburetors
US3198497A (en) * 1961-07-19 1965-08-03 Sibe Carburetors for internal combustion engines
US3198498A (en) * 1961-10-09 1965-08-03 Sibe Pressure carburetors
US3278171A (en) * 1963-10-28 1966-10-11 Acf Ind Inc Carburetor
US3295839A (en) * 1964-04-29 1967-01-03 Gen Motors Corp Carburetor idle air bypass arrangement
US3455260A (en) * 1965-10-25 1969-07-15 Sibe Carburettors for internal combustion engines
US3409277A (en) * 1966-06-24 1968-11-05 Acf Ind Inc Metering jet adjustable fuel by-pass

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3959417A (en) * 1973-07-14 1976-05-25 Toyota Judosha Kogyo Kabushiki Kaisha Carburetor
US4021513A (en) * 1973-11-07 1977-05-03 The Zenith Carburetor Company Limited Carbureters
US4136139A (en) * 1976-12-16 1979-01-23 Toyota Jidosha Kogyo Kabushiki Kaisha Variable venturi type carburetor

Also Published As

Publication number Publication date
GB1295774A (enrdf_load_stackoverflow) 1972-11-08
FR2087947A5 (enrdf_load_stackoverflow) 1971-12-31
SE362684B (enrdf_load_stackoverflow) 1973-12-17
DE2114921A1 (de) 1971-10-14

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