US3633557A - Diaphragm carburetor - Google Patents

Diaphragm carburetor Download PDF

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Publication number
US3633557A
US3633557A US7190A US3633557DA US3633557A US 3633557 A US3633557 A US 3633557A US 7190 A US7190 A US 7190A US 3633557D A US3633557D A US 3633557DA US 3633557 A US3633557 A US 3633557A
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US
United States
Prior art keywords
carburetor
idle
fuel
passage
diaphragm
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
US7190A
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English (en)
Inventor
Charles H Tuckey
Kenneth C Schneider
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.)
Wallro Corp
Original Assignee
Wallro Corp
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Filing date
Publication date
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Publication of US3633557A publication Critical patent/US3633557A/en
Anticipated expiration legal-status Critical
Assigned to HARRIS TRUST AND SAVINGS BANK, A IL BANKING CORPORATION reassignment HARRIS TRUST AND SAVINGS BANK, A IL BANKING CORPORATION SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WALBRO CORPORATION A CORP. OF DE
Expired - Lifetime legal-status Critical Current

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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
    • F02M7/06—Means for enriching charge on sudden air throttle opening, i.e. at acceleration, e.g. storage means in passage way system
    • 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
    • F02M17/00—Carburettors having pertinent characteristics not provided for in, or of interest apart from, the apparatus of preceding main groups F02M1/00 - F02M15/00
    • F02M17/02—Floatless carburettors
    • F02M17/04—Floatless carburettors having fuel inlet valve controlled by diaphragm
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
    • 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
    • Y10S261/68—Diaphragm-controlled inlet valve

Definitions

  • a passage is provided in the carburetor to receive crankcase pulses from the two-cycle engine being controlled, and to expose these pulses to the idle system so that under full throttle conditions the pulses will be open to the idle system to blow collected fuel in that system back to the main jet as an acceleration charge and also to dry out the idle system so that upon the closing of the throttle there will be a delayed fuel flow through the idle system to prevent overrich comedown.
  • This is accomplished by surface passages and a circuit gasket in the top wall ofthe diaphragm chamber to simplify the construction of the system.
  • This invention relates to a carburetor design and more particularly to a carburetor utilizing a system wherein crankcase pressure is open to the idle fuel passage under open throttle conditions to dry out the idle system while at the same time moving fuel into the carburetor as an acceleration charge.
  • FIG. I an end elevation of a carburetor assembly.
  • FIG. 2 a side elevation.
  • FIG. 3 an elevation of the other end of the carburetor assembly.
  • FIG. 4 a sectional view on line 44 of FIG. 2.
  • FIG. 5 a bottom view of the carburetor taken from the diaphragm chamber.
  • FIG. 6 a bottom view with a channeled circuit gasket in position.
  • FIG. 7 a partial sectional view on line 7-7 of FIG. 2.
  • FIG. 8 a pressure speed curve
  • FIGS. 9 and 10 diagrammatic presentations of the main jet and idle jet fuel passages illustrating the throttle control shaft.
  • the carburetor has a main body 10 with a mixing passage 12 in which is a throttle valve 14 mounted on a shaft 16 controlled by a lever 18.
  • a top plate 20 forms a standard fuel pump on the carburetor body taking fuel from the fuel inlet 22 and delivering it to the carburetor diaphragm chamber through a diaphragm-controlled valve in a conventional circuit including the fuel pump, the inlet valve, and the metering diaphragm.
  • a small arm 24 held on the end of a throttle shaft by a cap screw 26.
  • the position of this arm 24, and the throttle valve, as shown in FIG. 2, is controlled by the conical end 28 of an adjustable set screw 30, as seen best in FIG. 4.
  • Holes 32 are for mounting the carburetor and a small hole 34 in the forward face of the carburetor and shown in FIG. 1 is utilized for receiving crankcase pressure pulses for actuating the pump in the top of the carburetor body under the housing cap 20.
  • crankcase pressure pulses of an engine on which the carburetor is mounted is valved by a portion of the throttle valve 16 as illustrated more in detail in FIGS. 9 and 10 by a hole in the shaft which allows pressure to pass to the idle system, in a manner to be described later, when the throttle shaft is in full open position.
  • the other end of the carburetor is shown with the mixing passage at 12 in which is positioned a choke valve 42 mounted on a shaft 44 extending through the housing, this shaft being controlled by a small arm 46.
  • the choke valve is shown in the open position to expose the venturi restriction 48 of the mixing passage.
  • a detent (not shown) which acts on flats of the choke shaft to locate it in open or closed position.
  • the housing 10 is shown with the cap 20 over the pump diaphragm 22 which delivers fuel into chamber 52 leading through a filter 54 to a passage 56 terminating at a valve seat 58.
  • This valve seat is controlled by a needle valve 60, the lower end of which is actuated by a lever end 62 fulcrummed at 64 having a control lever end 66 actuated by a diaphragm 68 in a diaphragm chamber 70, the diaphragm being held in place by the bottom plate 72 of the carburetor with a suitable gasket 74.
  • a coil spring 76 urges lever end 66 downwardly to close the valve 60 except when actuated to an open position by the diaphragm 68.
  • An intermediate plate 80 carries the fulcrum pin 64 for the lever ends or lever arms and this plate holds in position a circuit gasket 82 which lies against a bottom face 84 of the carburetor body.
  • Two flathead screws 86 are mounted in holes 88 to mount the plate 80 and also hold the circuit gasket 82 in place firmly against the bottom face 84.
  • the face 84 at the bottom of the carburetor has a check valve cavity 90 in which is mounted a filter screen 92 carried by a cage 94 which also serves as a seat for a unidirectional valve 96.
  • Check valve cavity 90 opens to the mixing passage 12 through a main orifice port 98.
  • an idle passage having a leg 102 near the center of face 84 and a leg I04 extending radially having idle ports 106 connected to the mixing passage.
  • a passageway 108 extends upwardly from legs 102 into the body (see FIG. 4) where it connects to the passage 36 (FIG. 1) which leads past the throttle shaft as previously described to be valved by the position of the shaft. It will be noted that the connection of passage 108 to 102 is approximately at the center of the diaphragm chamber which gives a balance of fuel head at this point regardless of the position of the tilt carburetor. Beyond this point, the fuel to the idle system is a mixture of air and fuel not materially affected by gravity. This concept is fully described in a copending application of Charles H. Tuckey, Ser. No. 853,597, filed Aug. 19, I969.
  • a rectangular port 110 extending upwardly into the body connects at one wall with a short passage 112 which serves as a control seat for a needle valve 114.
  • the passage 112 leads to a port 116 which connects through the circuit gasket 82 and the plate 80 to the diaphragm chamber 70 (FIG. 7).
  • a similar rectangular port 120 shown in FIG. 5 connected at one wall to a short passage 122 is controlled by a needle valve 124 for idle adjustment, the passage I22 terminating in a passage 126 which forms part of an idle system in a manner to be described in connection with the circuit gasket.
  • Other recesses in the carburetor face 82 include an arcuate passage 128 at the top of the drawing in FIG. 5 and an arcuate passage 130 at the bottom of the drawing, the function of which will be later described.
  • a circular recess 132 serves as a spring seat for spring 76 previously described.
  • a small recess 134 at the circumference of the chamber 70 serves as a locator for a locator tab 136 on the circuit gasket shown in FIG. 6.
  • This circuit gasket 82 has a radial segment removed to provide an opening 138 for the operation of the needle valve 60 and the lever end 62.
  • circuit gasket has a passage 140 which leads from the chamber 110 to the arcuate passage 128 and a second passage 142 which leads from the passage 128 to the check valve cavity 90.
  • the two needle valve controls in the chambers 110 and 120 are in series in the sense that all of the fuel supply to the check valve cavity 90 passes the needle valve 114 and all of the idle fuel also passes this cavity 90 and then on to the additional passages leading to the idle needle control at chamber 120.
  • the passage 108 terminates at 102 leading to the idle jets and this passage receives crankcase pressure from the passage 36 originating at the face of the carburetor (see FIG. 1).
  • Passage 36 is controlled by a hole formed in the throttle shaft 16, this hole being aligned with the passage 36 when the throttle valve is in the open position.
  • FIGS. 9 and 10 a diagrammatic presentation of the circuits has been shown in FIGS. 9 and 10.
  • the flow of fuel will be evident from the main jet recess 110 to the check valve cavity 90 leading to the mixing passage and then the idle fuel takeoff 144 leads to the idle fuel recess 120 and then to the passages 130 and 148 to the idle passage 100.
  • the juncture of the passages 148 and 100 is connected to the passage 36 which passes through the opening for the throttle valve shaft 16.
  • the throttle shaft has a cross passage 40 which, in the position shown in FIG. 9, with the throttle valve in open position, connects crankcase pulse pressure from the face of the carburetor to the idle system, thus blowing out all of the idle fuel either to the idle ports 106 or back into the check valve cavity 90. Since the path to the main nozzle 98 offers least resistance, the bulk of the fuel will move through it.
  • the cross port 40 is closed and a small portion of the shaft 16 if cut away at 150 into the main mixing passage 12 so that passage 36 leading to passage 100 is vented.
  • the crankcase pulse is blocked off by the closing of the throttle permitting the idle system to work independently of the crankcase pressure.
  • the throttle is opened, all of the fuel in the idle system will blow back through the passages 148, 130, 126 and 144 to the check valve cavity 90, thus creating an accelerating charge as the throttle is moved to open position.
  • This dries out the idle system so that when the throttle is cutback from full throttle to idle, there is a certain amount of time delay for the refilling of the idle system and this prevents what is called a rich comedown or underrun.
  • a carburetor system for an internal combustion engine including a carburetor body with a main nozzle and an idle port leading to a mixing passage and a throttle valve in said passage movable from a closed to an open position, that improvement which comprises:
  • crankcase pulse passageway adapted to be connected at one end to the crankcase of an engine to which fuel is being delivered and connected directly at the other end to said passageway between said idle control valve and said idle port, and
  • a carburetor system as defined in claim I in which the carburetor body includes a diaphragm chamber having one wall formed by said body, a diaphragm in said chamber, and a valve controlled by said diaphragm to admit fuel to said chamber and thence to the fuel inlet, said passageways in said body being formed in part in said one wall of said body and in part by openings in a circuit gasket lying adjacent said wall.
  • a carburetor and two-cycle engine combination in which the carburetor is mounted on the engine, the carburetor having a main nozzle and one or more idle ports leading to a mixing passage and a throttle valve in said passage movable from a closed to open position, that improvement which comprises:
  • a. means forming a fuel flow passage from a fuel inlet to a main nozzle opening, thence to an idle passage leading to an idle port opening,
  • a carburetor as defined in claim 4 in which the means forming said fuel flow passage comprises a wall of said carburetor having passages cut into its surface, a circuit gasket having perforate passages formed therein and positioned to form continuous passages formed therein and positioned to form continuous passages in conjunction with the surface passages of said wall, and a closing plate overlying said circuit gasket closing one side of said perforate passages and pressing said gasket tightly on said surface to confirm and isolate said passages in said surface and said gasket.

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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)
US7190A 1970-01-30 1970-01-30 Diaphragm carburetor Expired - Lifetime US3633557A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US719070A 1970-01-30 1970-01-30
US19161571A 1971-10-22 1971-10-22

Publications (1)

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US3633557A true US3633557A (en) 1972-01-11

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US7190A Expired - Lifetime US3633557A (en) 1970-01-30 1970-01-30 Diaphragm carburetor
US00191615A Expired - Lifetime US3743253A (en) 1970-01-30 1971-10-22 Diaphragm carburetor

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Application Number Title Priority Date Filing Date
US00191615A Expired - Lifetime US3743253A (en) 1970-01-30 1971-10-22 Diaphragm carburetor

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US (2) US3633557A (de)
DE (1) DE2103839C3 (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3933949A (en) * 1974-05-03 1976-01-20 Borg-Warner Corporation Charge forming apparatus
US4104994A (en) * 1976-09-01 1978-08-08 Borg-Warner Corporation Charge forming method and apparatus with accelerating system
US5262092A (en) * 1993-01-26 1993-11-16 Walbro Corporation Synthetic composite fuel metering membrane
US6079379A (en) * 1998-04-23 2000-06-27 Design & Manufacturing Solutions, Inc. Pneumatically controlled compressed air assisted fuel injection system
US6273037B1 (en) 1998-08-21 2001-08-14 Design & Manufacturing Solutions, Inc. Compressed air assisted fuel injection system
US6293235B1 (en) 1998-08-21 2001-09-25 Design & Manufacturing Solutions, Inc. Compressed air assisted fuel injection system with variable effective reflection length
EP1184561A2 (de) * 2000-08-29 2002-03-06 Walbro Corporation Vergaser mit Einrichtung zur Behandlung von Kraftstoffdampf
US11168646B2 (en) 2017-11-22 2021-11-09 Tti (Macao Commercial Offshore) Limited Carburetor having integrated filter

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4003968A (en) * 1973-06-01 1977-01-18 Borg-Warner Corporation Charge forming method and apparatus
US4001354A (en) * 1975-11-17 1977-01-04 Walbro Corporation Cover plate for a carburetor body
US4814114A (en) * 1988-07-21 1989-03-21 Walbro Corporation Diaphragm-controlled carburetor with manual fuel enrichment
USRE34224E (en) * 1988-11-04 1993-04-20 Tecumseh Products Company Method of making a carburetor
US5049318A (en) * 1988-11-04 1991-09-17 Tecumseh Products Company Carburetor assembly
GB0811480D0 (en) * 2008-06-23 2008-07-30 Bcb Int Ltd Articulated modular armour
US8561213B2 (en) 2010-11-17 2013-10-22 Bcb International Limited Multi-paneled protective undergarment

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2680605A (en) * 1950-10-20 1954-06-08 R F Bracke & Company Carburetor
US3085791A (en) * 1960-08-23 1963-04-16 Tillotson Mfg Co Charge forming apparatus
US3231249A (en) * 1962-07-30 1966-01-25 Acf Ind Inc Carburetor
US3253822A (en) * 1964-03-09 1966-05-31 Walbro Corp Self-lift carburetor
US3453994A (en) * 1966-07-11 1969-07-08 Tillotson Mfg Co Fuel feed system and charge forming apparatus
US3593967A (en) * 1969-11-28 1971-07-20 Borg Warner Diaphragm carburetor having fuel channel system for engine idling and acceleration

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3933949A (en) * 1974-05-03 1976-01-20 Borg-Warner Corporation Charge forming apparatus
US4104994A (en) * 1976-09-01 1978-08-08 Borg-Warner Corporation Charge forming method and apparatus with accelerating system
US5262092A (en) * 1993-01-26 1993-11-16 Walbro Corporation Synthetic composite fuel metering membrane
US6079379A (en) * 1998-04-23 2000-06-27 Design & Manufacturing Solutions, Inc. Pneumatically controlled compressed air assisted fuel injection system
US6286469B1 (en) 1998-04-23 2001-09-11 Design & Manufacturing Solutions, Inc. Pneumatically controlled compressed air assisted fuel injection system
US6273037B1 (en) 1998-08-21 2001-08-14 Design & Manufacturing Solutions, Inc. Compressed air assisted fuel injection system
US6293235B1 (en) 1998-08-21 2001-09-25 Design & Manufacturing Solutions, Inc. Compressed air assisted fuel injection system with variable effective reflection length
US6295957B1 (en) 1998-08-21 2001-10-02 Design & Manufacturing Solutions, Inc. Compressed air assisted fuel injection system
EP1184561A2 (de) * 2000-08-29 2002-03-06 Walbro Corporation Vergaser mit Einrichtung zur Behandlung von Kraftstoffdampf
EP1184561A3 (de) * 2000-08-29 2003-08-13 Walbro Corporation Vergaser mit Einrichtung zur Behandlung von Kraftstoffdampf
US11168646B2 (en) 2017-11-22 2021-11-09 Tti (Macao Commercial Offshore) Limited Carburetor having integrated filter

Also Published As

Publication number Publication date
DE2103839A1 (de) 1971-08-05
US3743253A (en) 1973-07-03
DE2103839C3 (de) 1973-09-27
DE2103839B2 (de) 1973-02-22

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Date Code Title Description
AS Assignment

Owner name: HARRIS TRUST AND SAVINGS BANK, 111 WEST MONROE ST.

Free format text: SECURITY INTEREST;ASSIGNOR:WALBRO CORPORATION A CORP. OF DE;REEL/FRAME:005660/0559

Effective date: 19910325