EP0209497B1 - Elektropneumatisches Gerät mit proportionaler differenzialer Wirkung zur Steuerung des Kraftstoffflusses durch den Vergaser des Motors eines Motorfahrzeugs - Google Patents

Elektropneumatisches Gerät mit proportionaler differenzialer Wirkung zur Steuerung des Kraftstoffflusses durch den Vergaser des Motors eines Motorfahrzeugs Download PDF

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Publication number
EP0209497B1
EP0209497B1 EP86830187A EP86830187A EP0209497B1 EP 0209497 B1 EP0209497 B1 EP 0209497B1 EP 86830187 A EP86830187 A EP 86830187A EP 86830187 A EP86830187 A EP 86830187A EP 0209497 B1 EP0209497 B1 EP 0209497B1
Authority
EP
European Patent Office
Prior art keywords
casing
pressure
capsule
electro
engine
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
EP86830187A
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English (en)
French (fr)
Other versions
EP0209497A3 (en
EP0209497A2 (de
Inventor
Vittorio Di Nunzio
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
Fiat Auto SpA
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 Fiat Auto SpA filed Critical Fiat Auto SpA
Publication of EP0209497A2 publication Critical patent/EP0209497A2/de
Publication of EP0209497A3 publication Critical patent/EP0209497A3/en
Application granted granted Critical
Publication of EP0209497B1 publication Critical patent/EP0209497B1/de
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
    • F02D41/28—Interface circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/12—Introducing corrections for particular operating conditions for deceleration
    • F02D41/123—Introducing corrections for particular operating conditions for deceleration the fuel injection being cut-off

Definitions

  • the present invention relates to an electro-pneumatic apparatus of the type defined in the introduction of appended Claim 1 (see EP-A-207010).
  • That known apparatus comprises a switching member including a case divided by a diaphragm into a first chamber, which is sealed and substantially evacuated, and a second chamber communicating with the induction manifold.
  • the said diaphragm controls an electric switch which in turn controls the energisation of the cut-off member.
  • means are provided to make the vacuum in said first chamber vary as a function of the elevation.
  • the switch of the control device must necessarily have substantial hysteresis in order to avoid spurious switchings at pressures around the operating threshold of the switch.
  • the detected pressure has a considerable undulation ("ripple"); it is also found that every time the fuel supply is restored after a cut-off period, the pressure has a characteristic damped oscillation of low frequency (about 1Hz) with an amplitude of about 20-40 mbar (15-30 mm Hg).
  • the mechanical hysteresis of the switch between its switchings for cutting off and restoring the supply it is necessary for the mechanical hysteresis of the switch between its switchings for cutting off and restoring the supply to be more than 40 mbar (30 mm Hg).
  • this sleeve acts to damp the oscillations in the pressure detected and, by reducing the ripples, allows the use of microswitches with smaller hystereiss values.
  • the filtering action of this calibrated passage which is provided principally to reduce the amplitude of the low-frequency oscillations in the pressure during restoration of the fuel supply after a cut-off, ends up by introducing an undesirable delay (about 1 second) in the restoration of the supply.
  • the object of the present invention is to provide electro-pneumatic apparatus for controlling the fuel supply which is free from the aforesaid disadvantages and thus has a faster operating speed both during cut off and restoration of the fuel supply and which is also very sensitive, allowing the use of cheaper microswitches with substantial hysteresis values and rendering superfluous the need to filter the oscillations in the pressure detected.
  • a differential pressure sensor sensitive to variations in the pressure in the casing is also mounted in the casing and cooperates with the absolute pressure sensor so that the movement of the control member of the switch is substantially equal to the sum of a first movement proportional to the absolute pressure in the casing and a second movement substantially proportional to the derivative of the pressure in the casing.
  • a carburettor of known type is indicated 1, includes a throttle valve 2 and is provided with a cut-off device 3 in the idling duct 4.
  • the cut-off device 3 is, for example, an electromagnet including a movable member 3a acting as an obturator, and an excitation winding 3b.
  • the control device 7 comprises a rigid casing 10, for example of plastics material, having an aperture 11 connected to the tube 8.
  • the casing 10 defines a chamber 12 which communicates with the induction manifold 5 through the aperture 11, the tube 8, and the pressure outlet 6 formed in the manifold.
  • An aneroid-type barometric capsule 13 and a capsule 23 having a calibrated hole 24 are located within the chamber 12. The capsules 13 and 23 are disposed mechanically in series.
  • a control rod 14 is applied to the centre of the outer face of the capsule 23 which does not face the aneroid capsule 13.
  • Two electrically-conductive blades 17 and 18 extend into the chamber 12 through the wall of the casing 10.
  • the blade 18 is connected to one end of the excitation winding 3b of the cut-off device 3, the other end of this winding being connected to earth.
  • the blade 17 is intended for connection to a direct current voltage supply V.
  • the free ends of the blade 17 and 18 face each other, in the chamber 12 and carry respective contact members 17a and 18a, as shown in Figure 1.
  • the rod 14 carried by the capsule 23 is in contact with the free end of the blade 18.
  • the capsule 13 is of aneroid type, that is, it is sealed with a residual internal pressure (theoretically) of zero, while the capsule 23, however, has a calibrated hole.
  • the pressure in the casing 10 varies correspondingly and, due to the deformation of the capsules 12 and 23, the rod 14 which controls the microswitch formed by the blades 17 and 18 moves.
  • the movement of the rod 14 is substantially equal to the sum of a movement due to the capsule 13 and a movement due to the capsule 23.
  • the first movement is proportional to the absolute pressure in the induction manifold 5 at any instant, while the second is a function of the variation in the pressure and, in particular, is nil when the pressure is constant.
  • the action of the apertured capsule 23 is substantially of the derivative or differential type.
  • the capsule 23 feels the effect of the difference between its internal pressure and the external pressure for a short period of time and hence undergoes a transitory compressive action.
  • This compression is exhausted at the moment when the pressure within the capsule reaches equilibrium with the external pressure by means of the calibrated hole 24.
  • the capsule 23 is thus subject to a compressive action for a period of time which depends on the diameter of the hole 24 and the volume of the capsule.
  • the rod 14 thus feels the permanent action of the aneroid capsule 13 and the transitory action, in the same direction and sense, of the differential capsule 23. To a certain extent, the latter temporarily reinforces the action exerted on the rod by the aneroid capsule.
  • Figure 2 shows graphs which enable the behaviour of the apparatus according to the invention to be explained more clearly.
  • the curve Pc represents the absolute pressure in the induction manifold of the engine and hence in the chamber 12, and the broken-line curve p, shows the corresponding changes in the pressure within the diaphragm 23.
  • the curves X1 and X2 represent the movements of the rod 14 and the blade 18 due to the aneroid capsule 13 and the differential capsule 23, respectively.
  • the curve x represents the resulting movement given by the sum of X1 and x 2 .
  • the respective threshold levels at which the fuel flow to the engine is restored and cut off are indicated p M (x M ) and p m (x m ).
  • the instant to represents the moment at which the accelerator pedal is released with the engine running.
  • the instant t is the moment at which the cut-off device 3 is de-energised and hence the fuel flow is interrupted to achieve fuel cut-off.
  • the instant t 2 represents the moment at which the fuel supply is restored.
  • the apparatus of the invention has numerous advantages. In the first place, spurious switchings of the microswitch 17,18 are eliminated, particularly in the release phases, even without the attenuation of the low-frequency oscillations in the pressure in the induction manifold. Moreover, the cut off and restoration of the fuel supply occur more rapidly. Finally, the apparatus has a very high sensitivity.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Control Of The Air-Fuel Ratio Of Carburetors (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Claims (2)

1. Elektropneumatische Vorrichtung zur Steuerung des Kraftstoffdurchflusses in einem Vergasermotor für Kraftfahrzeuge
mit einer elektrisch gesteuerten Absperrvorrichtung (3) zum Unterbrechen der Kraftstoffzufuhr zu dem Motor,
mit einer Steuervorrichtung (7) mit einem starren Gehäuse (10), das mit dem Einlaßkrümmer (5) des Motors verbunden ist,
mit einem in dem Gehäuse (10) montierten elektrischen Schalter (17, 18) mit einem beweglichen Steuerglied (18), mit einem barometrischen Absolutdrucksesnor (13), der in dem Gehäuse (10) angeordnet ist und mit dem beweglichen Steuerglied (18) zusammenwirkt, um die Absperrvorrichtung (3) über den Schalter (17, 18) ein- und auszuschalten, wenn in dem Einlaßkrümmer (5) und damit in dem Gehäuse (10) vorbestimmte Druckbedingungen herrschen, dadurch gekennzeichnet,
daß in dem Gehäuse (10) ferner ein auf Drukkänderungen in dem Gehäuse ansprechender Differentialdrucksensor (23) montiert ist, der mit dem Absolutdrucksensor (13) derart zusammenwirkt, daß die Bewegung des Steuergliedes des Schalters (17, 18) bei Druckänderung in dem Gehäuse (10) im wesentlichen der Summe aus einer des Druck in dem Gehäuse (10) proportionalen ersten Bewegung un deiner zweiten Bewegung entspricht, die im wesentlichen der Druckänderung in dem Gehäuse (10) proportional ist.
2. Elektropneumatische Vorrichtung nach Anspruch 1, bei der der Absolutdrucksensor eine Dosenbarometerkapsel (13) ist, dadurch gekennzeichnet, daß der Differentialdrucksensor eine Kapsel (23) mit einer kalibrierten Öffnung (24) versehen ist und in dem Gehäuse (10) mit der Dosenbarometerkapsel (13) mechanisch in Reihe angeordnet ist.
EP86830187A 1985-07-12 1986-07-02 Elektropneumatisches Gerät mit proportionaler differenzialer Wirkung zur Steuerung des Kraftstoffflusses durch den Vergaser des Motors eines Motorfahrzeugs Expired EP0209497B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT67645/85A IT1182512B (it) 1985-07-12 1985-07-12 Dispositivo elettropneumatico ad azione combinata proporzionale derivativa per il controllo del flusso del carburante in un motore a carburazione per autoveicoli
IT6764585 1985-07-12

Publications (3)

Publication Number Publication Date
EP0209497A2 EP0209497A2 (de) 1987-01-21
EP0209497A3 EP0209497A3 (en) 1987-03-25
EP0209497B1 true EP0209497B1 (de) 1988-11-09

Family

ID=11304176

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86830187A Expired EP0209497B1 (de) 1985-07-12 1986-07-02 Elektropneumatisches Gerät mit proportionaler differenzialer Wirkung zur Steuerung des Kraftstoffflusses durch den Vergaser des Motors eines Motorfahrzeugs

Country Status (5)

Country Link
EP (1) EP0209497B1 (de)
BR (1) BR8603340A (de)
DE (1) DE3661149D1 (de)
ES (1) ES8705571A1 (de)
IT (1) IT1182512B (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3836556A1 (de) * 1988-10-27 1990-05-03 Bayerische Motoren Werke Ag Verfahren zur adaption der gemischsteuerung bei brennkraftmaschinen
US5771861A (en) * 1996-07-01 1998-06-30 Cummins Engine Company, Inc. Apparatus and method for accurately controlling fuel injection flow rate

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2856167A (en) * 1956-04-05 1958-10-14 Holley Carburetor Co Electrically actuated fuel shut-off apparatus
US2933168A (en) * 1957-08-23 1960-04-19 William E Leibing Deceleration controlled fuel shut-off means
US3161741A (en) * 1961-01-19 1964-12-15 Jr Robert D Wren Altitude compensator for vacuum control of idling valve
FR1461577A (fr) * 1965-10-25 1966-02-25 Sibe Perfectionnements apportés aux dispositifs d'alimentation en combustible pour moteurs à explosion

Also Published As

Publication number Publication date
ES556413A0 (es) 1987-05-01
IT1182512B (it) 1987-10-05
ES8705571A1 (es) 1987-05-01
IT8567645A0 (it) 1985-07-12
BR8603340A (pt) 1987-02-24
DE3661149D1 (en) 1988-12-15
EP0209497A3 (en) 1987-03-25
EP0209497A2 (de) 1987-01-21

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