EP0433734A1 - Appliance for calibration of carbon monoxide in a vehicle provided with an injection system - Google Patents

Appliance for calibration of carbon monoxide in a vehicle provided with an injection system Download PDF

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Publication number
EP0433734A1
EP0433734A1 EP90122983A EP90122983A EP0433734A1 EP 0433734 A1 EP0433734 A1 EP 0433734A1 EP 90122983 A EP90122983 A EP 90122983A EP 90122983 A EP90122983 A EP 90122983A EP 0433734 A1 EP0433734 A1 EP 0433734A1
Authority
EP
European Patent Office
Prior art keywords
time
appliance
periods
calculation
carbon monoxide
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.)
Withdrawn
Application number
EP90122983A
Other languages
German (de)
English (en)
French (fr)
Inventor
Vito Scartezzini
Roberto Mollea
Gianni Sterza
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 EP0433734A1 publication Critical patent/EP0433734A1/en
Withdrawn legal-status Critical Current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
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/1452—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a COx content or concentration
    • F02D41/1453—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a COx content or concentration the characteristics being a CO content or concentration

Definitions

  • the present invention relates to an appliance for calibrating carbon monoxide in a vehicle provided with an injection system.
  • the present invention relates more particularly to an appliance which can be used to advantage for carrying out the calibration of carbon monoxide in a vehicle provided with an injection system of a known type which makes available, at its own output, an alternative square wave signal whose path is a function of the titre of the air-fuel mixture.
  • the exhaust gases are sampled directly from the exhaust pipe located downstream from the ordinary exhaust box, and the percentage of carbon monoxide is read by means of a suitable instrument.
  • the terminals of the injection system which are normally connected to the throttle valve position sensor, it is possible to obtain a square wave signal whose path is a function of the titre.
  • the voltage level will result mainly in a high logic value, and vice versa, whereas if the engine operates stoichiometrically, the wave form exhibits a duty cycle which is roughly equal to 50%, but with a highly variable frequency.
  • the signal is recorded ultimately by an instrument provided with an index and connected to a self-diagnosis terminal in the injection system. Because of the slowness of the signal the reading time lasts several tenths of a second, and the stoichiometric operation of the engine is achieved when the sums of the holding times of the instrument in terms of high and low logic levels are almost equal.
  • the object of this invention is to provide an appliance which enables the carbon monoxide to be calibrated to a minimum value by a method which is simple, fast and not excessively expensive.
  • the aforementioned object is achieved by the present invention in that it relates to an appliance which can be used to calibrate carbon monoxide in a vehicle provided with an injection system of the type capable of making available, at its own output, an alternative square wave signal whose path is a function of the titre of the air-fuel mixture, characterised in that it comprises means for calculating the percentage value of the duty cycle of the said alternative signal, and means for displaying the result of the said calculation numerically and/or in the form of a histogram.
  • figure 1 is a block diagram of an appliance designed according to the present invention
  • figure 2 illustrates the path of two wave forms of electrical signals sampled from predetermined points in the diagram in figure 1.
  • an appliance which can be used to advantage to calibrate carbon monoxide in a vehicle provided with an injection system 2 of known type, is denoted in its entirety by 1, which appliance makes available, at an output terminal 3, an alternative square wave signal (Va in figure 2a), whose path is a function of the titre of the air-fuel mixture.
  • Appliance 1 comprises essentially a unit 5 for calculating the percentage value of the duty cycle of the aforementioned alternative signal Va, and means 6 for displaying the result of this calculation.
  • More particularly terminal 3 is connected, by means of a decoupling circuit 7, to a frequency duplicator circuit 8, which generates, at its own output, a signal Vb having the path illustrated in figure 2b.
  • circuits 7 and 8 are connected to respective inputs 11, 12 of calculation unit 6, which is provided with a further input 13, to which is transmitted a signal generated by an oscillator 15.
  • Unit 5 is provided with a counter 16 capable of counting the duration of the periods of time during which signal Va remains at a high level (period T1) and a low level (period T0).
  • the output signal of counter 16 is transmitted, at times t1 or t3, and at time 2, to memory units 17, 18, respectively, by means of commutator circuit 19, so that the duration of period T0 is stored in memory 17, and the duration of period T1 is stored in memory 18.
  • Memory units 17 and 18 should preferably consist of staggered (scaled) registers provided with several memory locations 17a, 18a (for example, five locations for each memory unit 17,18). In this manner the last five items of data relating to the durations of the aforementioned periods of time T0, T1, are held in the memory so that the insertion of a new item of data determines the cancellation of the data contained in the respective longer memory.
  • Memory locations 17a, 18a are provided with parallel outputs which are connected to the respective inputs of a calculation block 20, which carries out the calculation of the ratio of the period of time T1 to the sum of periods T1 + T0, and multiplies the value obtained by 100. This calculation is carried out on all the corresponding memory locations (there are five in this case), and the mean value of the result obtained is then calculated.
  • the result of this processing is made available to an output 14 of unit 5, and is displayed, by means of control circuits 21, 22, in a linear VDU (visual display unit) 23 and in a numeric VDU 24, or the dot matrix type, respectively.
  • the indication supplied by VDU 23 generates a histogram which makes it possible to identify, by means of a couple of reference arrows 25, a range of permitted values for obtaining good adjustment of the engine, from the point of view of the carbon oxide content in the exhaust gases, to the minimum value.
  • appliance 1 has already been explained in detail in the preceding part of the description, but for a clearer understanding the principal steps are now recapitulated, with particular reference to figure 2.
  • any switching of signal Va activates a procedure in calculation unit 5, which is capable of distinguishing a rising front (time t1, t3) from a descending front (time 2).
  • the measuring procedure is only initiated in conjunction with a rising front, according to the sequence described as follows:
  • VDU 6 The result displayed in VDU 6 is that which is obtained, as already mentioned, from the floating mean value of five consecutive readings. It is obvious that where signal Va is permanently stable at a high or low logic level, no switching would be obtained, and hence there would be no indication in unit 6, but this event would already signal the presence of a fault or the complete decalibration of the injection system.
  • appliance 1 renders the measurement free from evaluations of the subjective type, thereby overcoming, extremely effectively, the dispersion (variation) of values between one measurement and the next (due to the variation in frequency of the tested signal), due to the calculation method used (floating mean from five counting cycles).
  • This method provides the operator with an indication which is sufficiently stable in time, and an indication which can therefore be correctly evaluated.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
EP90122983A 1989-12-18 1990-11-30 Appliance for calibration of carbon monoxide in a vehicle provided with an injection system Withdrawn EP0433734A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT6811289 1989-12-18
IT06811289A IT1237698B (it) 1989-12-18 1989-12-18 Apparecchiatura per la taratura dell'ossido di carbonio in un veicolo provvisto di sistema di iniezione

Publications (1)

Publication Number Publication Date
EP0433734A1 true EP0433734A1 (en) 1991-06-26

Family

ID=11307938

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90122983A Withdrawn EP0433734A1 (en) 1989-12-18 1990-11-30 Appliance for calibration of carbon monoxide in a vehicle provided with an injection system

Country Status (3)

Country Link
EP (1) EP0433734A1 (it)
BR (1) BR9006540A (it)
IT (1) IT1237698B (it)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US738341A (en) * 1902-03-20 1903-09-08 Otto Markiewicz Folding theater-chair.
US3957372A (en) * 1974-12-19 1976-05-18 United Technologies Corporation Vehicle exhaust gas analysis system
EP0008199A1 (en) * 1978-08-14 1980-02-20 Beckman Instruments, Inc. Apparatus for determining hydrocarbon combustion efficiency and method and apparatus for analyzing i.c. engine faults
FR2465222A1 (fr) * 1979-09-17 1981-03-20 Professional General Elect Methode pour diminuer la consommation en ameliorant les proprietes de detection d'incendie des elements semi-conducteurs sensibles aux gaz
DE3025985A1 (de) * 1980-07-09 1982-01-28 Karl Dungs Gmbh & Co, 7067 Urbach Ueberwachungsvorrichtung
EP0277826A2 (en) * 1987-02-04 1988-08-10 LUCAS INDUSTRIES public limited company Electronic control system for an IC engine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US738341A (en) * 1902-03-20 1903-09-08 Otto Markiewicz Folding theater-chair.
US3957372A (en) * 1974-12-19 1976-05-18 United Technologies Corporation Vehicle exhaust gas analysis system
EP0008199A1 (en) * 1978-08-14 1980-02-20 Beckman Instruments, Inc. Apparatus for determining hydrocarbon combustion efficiency and method and apparatus for analyzing i.c. engine faults
FR2465222A1 (fr) * 1979-09-17 1981-03-20 Professional General Elect Methode pour diminuer la consommation en ameliorant les proprietes de detection d'incendie des elements semi-conducteurs sensibles aux gaz
DE3025985A1 (de) * 1980-07-09 1982-01-28 Karl Dungs Gmbh & Co, 7067 Urbach Ueberwachungsvorrichtung
EP0277826A2 (en) * 1987-02-04 1988-08-10 LUCAS INDUSTRIES public limited company Electronic control system for an IC engine

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 7, no. 177 (M-233) 05 August 1983, & JP-A-58 079644 (TOYOTA JIDOSHA K.K.) 13 May 1983, *
PATENT ABSTRACTS OF JAPAN vol. 9, no. 46 (M-360) 27 February 1985, & JP-A-59 185855 (NIHON DENSHI KIKI K.K.) 22 October 1984, *

Also Published As

Publication number Publication date
IT8968112A0 (it) 1989-12-18
IT8968112A1 (it) 1991-06-18
IT1237698B (it) 1993-06-15
BR9006540A (pt) 1991-10-01

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