EP0422270B1 - Luft-Kraftstoff-Verhältnissteuerungsvorrichtung für Einspritzvergaser - Google Patents

Luft-Kraftstoff-Verhältnissteuerungsvorrichtung für Einspritzvergaser Download PDF

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Publication number
EP0422270B1
EP0422270B1 EP19890118875 EP89118875A EP0422270B1 EP 0422270 B1 EP0422270 B1 EP 0422270B1 EP 19890118875 EP19890118875 EP 19890118875 EP 89118875 A EP89118875 A EP 89118875A EP 0422270 B1 EP0422270 B1 EP 0422270B1
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EP
European Patent Office
Prior art keywords
negative pressure
fuel
slow
control unit
air
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
Application number
EP19890118875
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English (en)
French (fr)
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EP0422270A1 (de
Inventor
Mitsuru Mikuni Kogyo Kabushiki Kaisha Sekiya
Shintaro Mikuni Kogyo Kabushiki Kaisha Takenaka
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Mikuni Corp
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Mikuni Corp
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Filing date
Publication date
Application filed by Mikuni Corp filed Critical Mikuni Corp
Priority to DE8989118875T priority Critical patent/DE68903172D1/de
Priority to EP19890118875 priority patent/EP0422270B1/de
Publication of EP0422270A1 publication Critical patent/EP0422270A1/de
Application granted granted Critical
Publication of EP0422270B1 publication Critical patent/EP0422270B1/de
Expired 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
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/46—Details, component parts or accessories not provided for in, or of interest apart from, the apparatus covered by groups F02M69/02 - F02M69/44
    • F02M69/467—Devices using intake air for generating a control signal acting on fuel delivery
    • 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
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/16—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for metering continuous fuel flow to injectors or means for varying fuel pressure upstream of continuously or intermittently operated injectors
    • F02M69/18—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for metering continuous fuel flow to injectors or means for varying fuel pressure upstream of continuously or intermittently operated injectors the means being metering valves throttling fuel passages to injectors or by-pass valves throttling overflow passages, the metering valves being actuated by a device responsive to the engine working parameters, e.g. engine load, speed, temperature or quantity of air
    • F02M69/20—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by means for metering continuous fuel flow to injectors or means for varying fuel pressure upstream of continuously or intermittently operated injectors the means being metering valves throttling fuel passages to injectors or by-pass valves throttling overflow passages, the metering valves being actuated by a device responsive to the engine working parameters, e.g. engine load, speed, temperature or quantity of air the device being a servo-motor, e.g. using engine intake air pressure or vacuum

Definitions

  • the invention concerns an air-fuel ratio control device for injection carburators comprising a slow fuel control unit and a main fuel control unit for slow and fast engine running conditions each including a negative pressure diaphragm forming a depression chamber for receiving negative pressures produced dependently on flow rates of air to be sucked into a suction bore, and a fuel injection valve for opening and closing a fuel injection port in accordance with displacement of said negative pressure diaphragm a negative pressure passage for introducing negative pressures from a venturi in the suction bore into the depression chamber of the main fuel control unit, a slow negative pressure passage for introducing negative pressure produced at a location downstream said venturi into the depression chamber of the slow fuel control unit.
  • Such an air-fuel ratio control device is known from GB-A-1 021 509, however, this known control device provides no possibility to add the negative pressure produced at a location downstream of a venturi and for introduction into a depression chamber of a slow fuel control unit into the main negative pressure passage so that the air-fuel control device is not capable of maintaining the air-fuel ratio of the mixture at a constant level during the transition from the slow zone to the main zone.
  • FIG. 1 is a sectional view illustrating the fundamental structure of the air-fuel ratio control device of the injection carburetor.
  • the reference numeral 1 represents a suction bore of a carburetor having a venturi 2
  • the reference numeral 3 designates a fuel control unit arranged at a location neighboring the venturi 2
  • the reference numeral 4 denotes an air section of regulator arranged at a location also neighboring the venturi 2 but on the side opposite to the fuel control unit 3 with regard to the suction bore 1.
  • the air section of regulator 4 has an air chamber and a depression chamber 5 which is separated from each other by a negative pressure diaphragm 6, and formed in the depression chamber 5 is an opening 5a for communication with the venturi 2.
  • a fuel section of regulator 7 has a fuel injection chamber 8 and a fuel pressure chamber 9 which are separated from each other by a fuel diaphragm 10, and formed in the fuel injection chamber 8 is a fuel injection port 8a in opposite to the opening 5a of the depression chamber 5.
  • the fuel injection chamber 8 is communicated with the fuel pressure chamber 9 through a main jet 11.
  • the reference numeral 12 represents a connecting member inserted through the opening 5a of the depression chamber 5 and the fuel injection port 8a of the fuel injection chamber 8, one end of the connecting member 12 is fixed to the negative pressure diaphragm 10 and the other end of the connecting member 12 is fixed to the fuel diaphragm 10.
  • a conical valve 12a capable of controlling opening degree of the fuel injection port 8a by opening and closing said port.
  • the reference numeral 13 represents a spring which is arranged in the depression chamber 5 and functions to urge the negative pressure diaphragm 6 upward, i.e., to move the valve 12a in the direction to close the fuel injection port 8a.
  • the injection carburetor of this type has a defect that a long time is required until an air-fuel ratio of the mixture attains to a target value corresponding to an opening degree of the throttle valve after it is opened widely in the main zone as shown in Fig. 2C.
  • Fig. 3 illustrates a carburetor so adapted as to control air-fuel ratio of the mixture in a broad range by combining two air-fuel ratio control devices having the fundamental structure illustrated in Fig. 1 as a slow fuel control unit 14 mainly for controlling the slow zone and a main fuel control unit 15 chiefly for controlling the main zone.
  • the members and parts of the slow fuel control unit 14 which are similar to those illustrated in Fig. 1 are represented by the same numerals but with a prime, and the members and parts of the main fuel control unit 15 similar to those shown in Fig. 1 are designated with the same numerals but with double primes.
  • the reference numeral 16 represents an air valve arranged openably and closably downstream the venturi 2 in the suction bore 1
  • the reference numeral 17 designates a stopper for holding the air valve 16 at the minimum opening degree thereof
  • the reference numeral 18 denotes a negative pressure actuator which is connected to the air valve 16, and functions to open and close the air valve 16 in conjunction with variation of the negative pressure produced downstream the air valve 16
  • the reference numeral 19 represents a throttle valve arranged downstream the air valve 16
  • the reference numeral 20 designates a fuel tank
  • the reference numeral 21 denotes a fuel pump.
  • the discharge side of the fuel pump 21 is communicated with the fuel pressure chamber 9 ⁇ of the main fuel control unit 15 and the fuel injection chamber 8 ⁇ thereof is communicated with the fuel pressure chamber 9′ of the slow fuel control unit 14.
  • the negative pressure chamber of the slow fuel control unit 14 is communicated with the suction bore 1 at a location downstream the air valve 16, whereas the negative pressure chamber of the main fuel control unit 15 is communicated with the venturi 2.
  • the fuel injection port 8a′ of the slow fuel control unit 14 and the fuel injection port 8a ⁇ of the main fuel control unit 15 are communicated with a fuel passage 22 which is open to the suction bore 1 at a location downstream the throttle valve 19.
  • the carburetor described above has already been proposed by the applicant and functions as follows.
  • a low negative pressure is produced downstream the air valve 16 and the negative pressure actuator does not operate. Accordingly, the air valve 16 is held at the position shown in Fig. 3 and only the slow fuel control unit 14 is set in the operating condition.
  • the slow fuel control unit 14 functions in the same manner as the fuel control unit described with reference to Fig. 1, and the fuel ejected through the fuel injection port 8a′ is discharged into the suction bore 1 through the fuel passage 22.
  • the negative pressure actuator operates to displace the air valve 16 to the fully open position thereof.
  • the negative pressure acting on the depression chamber of the slow fuel control unit 14 is gradually reduced and the negative pressure acting on the depression chamber of the main fuel control unit 15 is gradually increased, whereby the fuel injection port 8a ⁇ of the main fuel control unit 15 begins to eject the fuel.
  • the fuel ejected from the fuel injection port 8a ⁇ is discharged into the suction bore 1 through the fuel passage 22 and operating condition of the engine shifts to the main zone.
  • both the slow fuel control unit 14 and the main fuel control unit 15 have the defect described with reference to the carburetor illustrated in Fig. 1, the air-fuel ratio controlled by both the fuel control units are disturbed as shown in Fig. 4 during the transition from the slow zone to the main zone, or the transition from the slow zone to the main zone is not performed smoothly.
  • a primary object of the present invention is to provide an air-fuel ratio control device for injection carburetors which is capable maintaining of air-fuel ratio of the mixture at a constant level during transition from the slow zone to the main zone.
  • Another object of the present invention is to provide an air-fuel ratio control device for injection carburetors which is capable of securely preventing unnecessary fuel from being discharged into the suction bore at the rest time or restart time of an engine.
  • a further object of the present invention is to provide an air-fuel ratio control device for injection carburetors which has very excellent responsibility over the entire operating range of an engine.
  • the air-fuel ratio control device allows the negative pressure produced downstream the air valve to be added at a predetermined ratio into the main negative pressure passage through the bypass passage so that a total of the negative pressure in the venturi and the added negative pressure if introduced into the depression chamber of the main fuel control unit in the slow zone, and opens the fuel injection valve to start discharging the fuel when the total negative pressure exceeds a predetermined level, whereby the air-fuel control device is capable of maintaining air-fuel ratio of the mixture at a constant level during the transition from the slow zone to the main zone.
  • a resilient means which functions to generate a force acting to close the fuel injection valve which is stronger than the force acting to open the fuel injection valve until the negative pressure to be introduced into the depression chamber of the main fuel control unit exceed the predetermined level. This means prevents the fuel from being leaked while the engine is rested or at the initial stage of the slow zone.
  • the reference numeral 25 represents a main negative pressure passage which is open to the venturi 2, has a jet 25a and serves for introducing a negative pressure P 1 of the venturi into the depression chamber of the main fuel control unit 15,
  • the reference numeral 26 designates a slow negative pressure passage which is open at a location downstream the air valve 16 and serves for introducing a negative pressure P 2 produced downstream the air valve 16 into the depression chamber of the slow fuel control unit 14,
  • the reference numeral 27 denotes a bypass passage communicated at one end thereof with the slow negative pressure passage 26 and at the other end thereof with the main negative pressure passage 25 at a location dowstream the jet 25a
  • the reference numeral 28 represents an adjusting screw which is adjustably provided in the bypass passage 27 and capable of adjusting a ratio of the negative pressure P 2 downstream the air valve 16
  • a reference symbol w 1 represents weight of the diaphragm assembly of the main fuel control unit 15
  • a reference symbol w 2 designates resilience of the spring 13 ⁇
  • a reference symbol w 3 denotes resilience of the spring 29
  • a reference symbol w 4 represents a force which is generated by the total negative pressure P 3 of the negative pressures P 1 and P 2 produced in the slow zone during operation of the engine, and acts to raise the diaphragm assembly.
  • Resilience of the spring 13 ⁇ and that of the spring 29 are selected so as to satisfy the following relation (1) in the rest condition of the engine and the following condition (2) when the force w 4 exceeds a predetermined value: w 3 ⁇ w 1 + w 2 w 3 + w 4 > w 1 + w 2
  • the air-fuel ratio control device illustrated in Fig. 3 is used as the slow fuel control unit 14.
  • the slow zone is switched to the main zone in a condition where the air-fuel ratio is maintained at the target value, and the condition is kept also in the main zone. (See Fig. 8A and Fig. 8B ) Further, at restart time after the engine is stopped, the above-mentioned relation (1) is satisfied and the fuel injection valve 12a ⁇ is kept at the closed condition thereof before the engine starts rotation even in the condition where the engine key is turned ON and the fuel pump 21 is operating.
  • the embodiment of the present invention prevents unnecessary fuel from being discharged at rest time of engine or initial stage of the slow zone since the force w 1 + w 2 acting to close the fuel injection valve 12a ⁇ is stronger than the force w 3 acting to close the valve 12a ⁇ at the engine rest time or initial stage of the slow zone before the total negative pressure P 3 in the depression chamber of the main fuel control unit 15, exceeds a predetermined level, assures stable operation of the fuel injection valve 12a ⁇ at opening start time thereof, and is capable of maintaining air-fuel ratio of the mixture at a constant level with the main fuel control unit 15 during transition from the slow zone to the main zone as well as in the main zone by adding a predetermined ratio of the negative pressure produced dependently on air flow rate into the depression chamber of the main fuel control unit 15 at the stage of the slow zone. Further, the embodiment of the present invention does not allow mechanical operation delay since opening and closing of the fuel injection valve 12a ⁇ are controlled by variation of the negative pressure.
  • the embodiment is so constructed as the strengthen the closing force for the fuel injection valve 12a ⁇ by the resilience of the spring 13 ⁇ , it is possible to select such a structure as the strengthen the closing force for the fuel injection valve 12a ⁇ weakening the resilience of the spring 28 with the spring 13 ⁇ omitted.

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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)

Claims (5)

  1. Luft-Kraftstoff-Verhältnissteuervorrichtung für Einspritzvergaser umfassend
    - eine langsame Kraftstoffsteuereinheit (14) und eine Hauptkraftstoffsteuereinheit (15) für langsame und schnelle Motorlaufzustände jeweils einschließend
    -- eine Unterdruckmembran (10′, 10˝), die eine Unterdruckkammer (5) zur Aufnahme von Unterdrücken (P2) erzeugt in Abhängigkeit von Durchströmmengen an in eine Ansaugbohrung (1) anzusaugende Luft bildet, und
    -- ein Kraftstoffeinspritzventil (12a′, 12a˝) zum Öffnen und Schließen einer Kraftstoffeinspritzöffnung (8a′, 8a˝) entsprechend der Verlagerung der besagten Unterdruckmembran (10′, 10˝),
    - einen Unterdruckdurchgang (25) zum Anlegen von Unterdrücken (P2) von einem Venturi (2) in der Ansaugbohrung (1) an die Unterdruckkammer (5) der Hauptkraftstoffsteuereinheit (15),
    - einen langsamen Unterdruckdurchgang (26) zum Anlegen von an einer Stelle stromabwärts von dem Venturi (2) erzeugtem Unterdruck an die Unterdruckkammer (5) der langsamen Kraftstoffsteuereinheit (14),
    dadurch gekennzeichnet, daß
    - der Unterdruck zum Anlegen an die Unterdruckkammer (5) der langsamen Kraftstoffsteuereinheit (14) stromabwärts eines in der Ansaugbohrung (1) angeordneten Luftventils (16) erzeugt wird,
    - einen Bypassdurchgang (27), die zwischen dem besagten Hauptunterdurchgang (25) und dem besagten langsamen Unterdruckdurchgang (26) angeordnet ist, vorgesehen ist, und
    - ein Einstellmittel (28), das in dem besagten Bypassdurchgang (27) angeordnet und in der Lage ist, von dem besagten langsamen Unterdruckdurchgang (26) in den besagten Hauptunterdruckdurchgang (25) einzuführende Unterdruckverhältnisse einzustellen, vorgesehen ist.
  2. Vorrichtung nach Anspruch 1, wobei das besagte Einstellmittel (28) als eine Einstellschraube ausgebildet ist, die in dem besagten Bypassdurchgang (27) angebracht und in der Lage ist, auf einen Querschnittsbereich des besagten Bypassdurchgangs (27) einzuwirken.
  3. Vorrichtung nach Anspruch 1, wobei das besagte Luftventil (16) ein Klappenventil ist.
  4. Vorrichtung nach Anspruch 1, wobei das besagte Luftventil (16) ein Kolbenventil ist.
  5. Vorrichtung nach einem der Ansprüche 1 bis 4, weiter umfassend ein nachgiebiges Mittel (13˝, 29), das derart funktioniert, daß eine Kraft, die wirkt, um das Kraftstoffeinspritzventil (12a′, 12a˝) der Hauptkraftstoffsteuereinheit (15) zu schließen, stärker als eine Kraft ist, die wirkt, um das besagte Ventil zu öffnen, bis der Unterdruck, der an die Unterdruckkammer (5) der besagten Hauptkraftstoffsteuereinheit (15) anzulegen ist, einen vorbestimmten Wert überschreitet, während der Betriebszustand der Maschine im trägen Bereich ist.
EP19890118875 1989-10-10 1989-10-10 Luft-Kraftstoff-Verhältnissteuerungsvorrichtung für Einspritzvergaser Expired EP0422270B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE8989118875T DE68903172D1 (de) 1989-10-10 1989-10-10 Luft-kraftstoff-verhaeltnissteuerungsvorrichtung fuer einspritzvergaser.
EP19890118875 EP0422270B1 (de) 1989-10-10 1989-10-10 Luft-Kraftstoff-Verhältnissteuerungsvorrichtung für Einspritzvergaser

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19890118875 EP0422270B1 (de) 1989-10-10 1989-10-10 Luft-Kraftstoff-Verhältnissteuerungsvorrichtung für Einspritzvergaser

Publications (2)

Publication Number Publication Date
EP0422270A1 EP0422270A1 (de) 1991-04-17
EP0422270B1 true EP0422270B1 (de) 1992-10-07

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890118875 Expired EP0422270B1 (de) 1989-10-10 1989-10-10 Luft-Kraftstoff-Verhältnissteuerungsvorrichtung für Einspritzvergaser

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DE (1) DE68903172D1 (de)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB547902A (en) * 1940-04-24 1942-09-16 United Aircraft Corp Improvements in or relating to fuel feeding or metering devices for an internal combustion engine
US2540735A (en) * 1945-06-29 1951-02-06 Niles Bement Pond Co Carburetor
GB1021509A (en) * 1962-08-21 1966-03-02 Heinrich Klaus Wucherer Improvements in and relating to carburettors
DE2024161A1 (de) * 1970-05-16 1971-12-02 Petrol Injection Ltd., Plymouth; Jackson, Harold Ernest, Plympton St. Mary; Devon (Großbritannien) Brennstoffeinspritzsystem
GB1546074A (en) * 1975-05-15 1979-05-16 Tecalemit Ltd Fuel injection systems for internal combustion engine
JPH01262331A (ja) * 1988-04-14 1989-10-19 Mikuni Corp 燃料噴射装置の空燃比制御機構

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EP0422270A1 (de) 1991-04-17
DE68903172D1 (de) 1992-11-12

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