EP0155273B1 - Fuel metering device for an internal combustion engine - Google Patents

Fuel metering device for an internal combustion engine Download PDF

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Publication number
EP0155273B1
EP0155273B1 EP84902912A EP84902912A EP0155273B1 EP 0155273 B1 EP0155273 B1 EP 0155273B1 EP 84902912 A EP84902912 A EP 84902912A EP 84902912 A EP84902912 A EP 84902912A EP 0155273 B1 EP0155273 B1 EP 0155273B1
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EP
European Patent Office
Prior art keywords
injection
internal combustion
combustion engine
ignition
control unit
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Expired
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EP84902912A
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German (de)
French (fr)
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EP0155273A1 (en
Inventor
Herbert Arnold
Werner Jundt
Siegfried Malicki
Peter Werner
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Robert Bosch GmbH
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Robert Bosch GmbH
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Priority to AT84902912T priority Critical patent/ATE31781T1/en
Publication of EP0155273A1 publication Critical patent/EP0155273A1/en
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Publication of EP0155273B1 publication Critical patent/EP0155273B1/en
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    • 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
    • F02D41/266—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor the computer being backed-up or assisted by another circuit, e.g. analogue

Definitions

  • the invention relates to a device for metering fuel in a spark-ignited internal combustion engine equipped with an injection system according to the preamble of the main claim.
  • Such devices include a control unit as an essential component, the functions of which are either hard-wired in terms of hardware or freely programmable, for example, by using a microcomputer.
  • control devices have already been described in detail in the relevant specialist literature and have long been part of the prior art. In practice, these control units have proven themselves well in terms of driving behavior and exhaust gas emissions from the fuel press.
  • a device is known from JP-A-58-144 664 in which, in the event of a defect in the microcomputer, the system is switched firstly to a “fixed ignition” dependent on a reference signal and the speed signal, and secondly to a fixed injection.
  • the auxiliary signals for the injection are supplied by a separate control device which is triggered by pulses obtained on the high voltage side of the ignition coil.
  • the auxiliary devices mentioned are complex since complete auxiliary control devices are necessary.
  • the device according to the invention with the features of the main claim has the advantage that an emergency operation mode is possible in the event of failure of the control unit without the use of such relatively complex auxiliary devices. Instead of the output signals of such auxiliary devices, the signals from the ignition system are used to control the fuel injection valves. This enables an extremely cost-effective emergency running concept to be implemented, which enables the driver of a motor vehicle equipped in this way to reach the nearest workshop even in the event of a failure of the control unit in a kind of emergency operation.
  • ignition signals are derived from an encoder that is not used to control the control unit. This system therefore also proves to be effective if an encoder fails for the main input variables of the control unit.
  • the measures listed in the subclaims make further advantageous developments and improvements of the device proposed in the main claim possible.
  • the simple coupling via a diode and a simple changeover switch has proven to be particularly simple and inexpensive. This feature is particularly high in those cases in which existing control devices are to be retrofitted with such a device.
  • FIG. 3 shows a possible embodiment of the two exemplary embodiments in FIGS. 1 and 2.
  • 10 denotes an ignition coil, which contains a primary winding 11, a secondary winding and an iron core 13.
  • the primary winding 11 is connected between the battery voltage U B and the collector of a transistor 14, the emitter of which is at ground potential.
  • the base of this transistor 14 is controlled by an ignition pulse generator 15, which can be designed, for example, as a mechanical interrupter, induction transmitter, Hall sensor, Wiegand sensor or also as an optical sensor.
  • the secondary coil 12 of the ignition coil 10 is connected on the input side to the connection point 16 between the primary coil and the collector of the transistor 14. On the output side, the high-voltage ignition signals lead to an ignition system, which is not shown.
  • a designated by the numeral 17 control unit the data on various operating parameters, such as the pressure p, n is the rotational speed, the temperature of 1 to 9, load information L or the intake air and injected fuel quantity Q is fed, supplies via a pipe 18, a Switch 19, which is in position A, sends injection pulses to a schematically illustrated injection valve 20.
  • the injection valve 20 is connected on the output side to the battery voltage U B. For the switch position of the switch 19 in position B, there is a connection between the connection point 16 via a diode 28 and the injection valve 20.
  • a fuel pump designated 21 receives its supply voltage U B via a switch 22 and is connected to ground potential with its other connection.
  • the switch 22 is connected to the control unit 17 via a control line 23.
  • the connection point between the fuel pump 21 and the switch 22 can be via a further one Switch 24 interrupted line are also placed on the potential of the supply voltage U B.
  • the switches 19 and 24 are controlled by a relay 25, which is activated by applying the battery voltage U B via a line from the control unit. In the activated state of the relay 25, the switches 19 and 24 are in the position labeled A.
  • the output lines of the control device 17 can be separated from the control device via a central plug 26.
  • the relay 25 is activated by applying the battery voltage U B via the central plug 26.
  • the injection pulses from the control unit reach the injection valves via line 18 and switch 19 (in position A).
  • the switch 22 is closed via the control line 23 and the fuel pump 21 supplies the fuel to the injection valves 20 via fuel lines (not shown).
  • the ignition works independently of the function of the control unit and delivers the corresponding ignition pulses to the spark plugs of the internal combustion engine, which are not shown in this picture.
  • the emergency drive function can be switched on in that the central plug 26 is removed from the control unit.
  • This measure is a very special embodiment; it would also be conceivable that the output lines of the control device can be interrupted via a switch installed in the motor vehicle.
  • switch 22 is then opened so that fuel pump 21 is decoupled from the supply voltage.
  • the relay 25 switches to its rest position, i.e. the two switches 19 and 24 move to the drawn position B. This has the consequence that the injector 20 is located via switch 19 (in position B) and the diode 28 at the connection point 16. The voltage supply to the fuel pump 21 is restored via the second switch 24 (in position B).
  • the connection point 16 is approximately at ground potential and the injection valve 20 is activated via the conductive diode 28.
  • the transistor 14 is blocked by the ignition pulse generator 15 for the purpose of generating an ignition spark, high positive voltages occur at the connection point 16, so that the diode 28 blocks and thus closes the injection valve 20. In this way, the injector 20 and the spark plugs are driven alternately.
  • the switch 24 can be omitted for exemplary embodiments in which the switch 22 is not controlled by the control device 17 but is actuated by other independent components.
  • the injection pulses t; or the load signals tp, as before, are fed to the injection valve 20 via the switch 19 (in position A).
  • these signals are also present at a speed relay 29 with which the switch 19 is actuated.
  • Start signal information from a start signal transmitter 30 can also be supplied to this speed relay.
  • the switch 22 for interrupting the supply voltage is not actuated by the control unit 17 but by a speed relay 31 which is connected on the input side to the connection point 16.
  • These speed relays 29 and 31 function in such a way that they switch when the value falls below a certain value of the pulse repetition frequency applied to their input, i.e. change their output size or press the assigned switch.
  • the relay is controlled by an electronic time stage, which is designed either as a retriggerable monostable multivibrator or as a retriggerable timer.
  • the timer is set, the relay picks up for a certain period of time and then drops again if no pulses arrive. The time period is chosen so that it is greater than the time pulse interval at the lowest speed.
  • the relay is also activated immediately in the event of a fault.
  • the speed relay When the engine is running, the speed relay is triggered again and again by the ignition pulses, so that the service life does not expire and the relay remains constantly energized.
  • the switching threshold for the pulse repetition frequency is in the region of 1 Hz, but it can also take on other values adapted to the vehicle.
  • the speed relay 31 switches off the fuel supply to the fuel pump 21 in the event of firing pulse sequences that fall below the set threshold value.
  • a possible malfunction of the control unit 17 is recognized by the speed relay 29 in the present exemplary embodiment. If there are no injection pulses or if the number of injection pulses falls below an adjustable number, the speed relay 29 switches the switch 19 to position B, so that here too, in the same way as in the exemplary embodiment in FIG. 1, the injection valve 20 releases the pulses via the diode 28 the ignition system is controlled at connection point 16.
  • a start signal generator 30 is provided which prevents the speed relay 29 from responding during the start phase.
  • the switchover to “emergency driving mode” takes place automatically, i.e. it is recognized by the speed relay 29.
  • the exemplary embodiment in FIG. 3 is used for active decoupling between the primary coil 11 of the ignition coil 10 and the injection valve 20.
  • identical components are identified by the same numbers.
  • the components which are not important for explaining the functioning of this exemplary embodiment have not been shown, but it is understood that this arrangement can be used in any of the previous exemplary embodiments.
  • Switch 19 is in position B, ie there is emergency driving operation before, in the present case the injection valve 20 is no longer directly connected to the diode 28.
  • the signals of the ignition system run from the connection point 16 via the diode 28, a resistor 32, the base-collector path of a transistor 33, the base-collector path of a further transistor 34 and the switch 19 (position B) to the injection valve 20.
  • the collector of the transistor 33 is connected to the supply voltage U B via a resistor 35, while the emitters of the transistors 33 and 34 are connected to ground potential.
  • This circuit arrangement which is known per se, has the advantage that the primary coil 11 of the ignition pulses 10 (not shown) is hardly loaded and thus sufficient decoupling between the injection valve 20 and the ignition system is achieved.

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

Abstract

Fuel metering device for an internal combustion engine fitted with an injection device and an independent ignition, with a control apparatus (17) producing at least as a function of the rotation speed (12) of the internal combustion engine injection pulses intended to the injection valves, a switching (19) being operated for controlling the injection valves by means of the injection pulses coming from the ignition unit (15) of the internal combustion engine in case of perturbation of the control apparatus. The switching may be carried out either by removing the central plug of the control apparatus or by an automatic error detection by means of a rotational speed relay.

Description

Die Erfindung geht aus von einer Einrichtung zur Kraftstoffzumessung bei einer fremdgezündeten, mit einer Einspritzanlage ausgerüsteten Brennkraftmaschine nach der Gattung des Hauptanspruchs. Derartige Einrichtungen beinhalten als wesentliche Komponente ein Steuergerät, dessen Funktionen entweder hardwaremässig fest verdrahtet oder beispielsweise durch den Einsatz eines Mikrocomputers frei programmierbar sind. Derartige Steuergeräte wurden schon ausführlich in der betreffenden Fachliteratur beschrieben und gehören seit langem zum Stand der Technik. In der Praxis haben sich diese Steuergeräte bezüglich des Fahrverhaltens und der Abgasemission der Brennkaftmaschine gut bewährt.The invention relates to a device for metering fuel in a spark-ignited internal combustion engine equipped with an injection system according to the preamble of the main claim. Such devices include a control unit as an essential component, the functions of which are either hard-wired in terms of hardware or freely programmable, for example, by using a microcomputer. Such control devices have already been described in detail in the relevant specialist literature and have long been part of the prior art. In practice, these control units have proven themselves well in terms of driving behavior and exhaust gas emissions from the fuel press.

Allerdings besteht aufgrung des relativ komplizierten Aufbaus dieser Steuergeräte die Möglichkeit des Ausfalls einzelner Komponenten. Ein Fehler in einer an sich nebensächlichen Komponente kann unter Umständen die Funktion des gesamten Steuergerätes und damit auch die Brennkraftmaschine lahmlegen. Zur Umgehung dieses Nachteils wurden schon zahlreiche Vorschläge unterbreitet, so z.B. in der Patentanmeldung WO 80/00597. In dieser Patentanmeldung wird vorgeschlagen, dem Steuergerät wenigstens eine gebergesteuerte Hilfsvorrichtung zuzuordnen, deren Ausgangssignale alternativ zu den Ausgangssignalen des Steuergerätes über eine Umschaltvorrichtung den Steuerendstufen, beispielsweise den Steuerendstufen einer elektrischen Einspritzanlage zuführbar sind. Dabei werden die Hilfsvorrichtungen von den Ausgangssignalen des gleichen Gebers angesteuert, der auch an das Steuergerät angeschlossen ist.However, due to the relatively complicated structure of these control units, there is the possibility of individual components failing. Under certain circumstances, a fault in a component that is irrelevant can paralyze the function of the entire control unit and thus also the internal combustion engine. Numerous proposals have already been made to circumvent this disadvantage, e.g. in patent application WO 80/00597. In this patent application it is proposed to assign at least one sensor-controlled auxiliary device to the control device, the output signals of which, as an alternative to the output signals of the control device, can be fed to the control output stages, for example the control output stages of an electrical injection system, via a switching device. The auxiliary devices are controlled by the output signals of the same encoder that is also connected to the control unit.

Weiterhin ist aus JP-A-58-144 664 eine Einrichtung bekannt, bei welcher bei Defekt des MikroComputers erstens auf eine von einem Referenzsignal und vom Drehzahlsignal abhängige «Fest-Zündung» und zweitens auf eine Festeinspritzung umgeschaltet wird. Die Hilfssignale für die Einspritzung werden von einer gesonderten Steuereinrichtung geliefert, die von an der Hochspannungsseite der Zündspule gewonnenen Impulsen getriggert wird. Die genannten Hilfsvorrichtungen sind aufwendig, da komplette Hilfssteuervorrichtungen nötig sind.Furthermore, a device is known from JP-A-58-144 664 in which, in the event of a defect in the microcomputer, the system is switched firstly to a “fixed ignition” dependent on a reference signal and the speed signal, and secondly to a fixed injection. The auxiliary signals for the injection are supplied by a separate control device which is triggered by pulses obtained on the high voltage side of the ignition coil. The auxiliary devices mentioned are complex since complete auxiliary control devices are necessary.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemässe Einrichtung mit den Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, dass eine Realisierung eines Notfahrbetriebes bei Ausfall des Steuergerätes ohne den Einsatz derartiger relativ aufwendiger Hilfsvorrichtungen möglich ist. Anstelle der Ausgangssignale derartiger Hilfsvorrichtungen werden die Signale der Zündanlage zur Ansteuerung der Kraftstoffeinspritzventile benutzt. Damit lässt sich ein extrem kostengünstiges Notlaufkonzept realisieren, das den Fahrer eines in dieser Art ausgerüsteten Kraftfahrzeuges in die Lage versetzt, auch bei einem Ausfall des Steuergerätes in einer Art Notfahrbetrieb die nächste Werkstatt zu erreichen.The device according to the invention with the features of the main claim has the advantage that an emergency operation mode is possible in the event of failure of the control unit without the use of such relatively complex auxiliary devices. Instead of the output signals of such auxiliary devices, the signals from the ignition system are used to control the fuel injection valves. This enables an extremely cost-effective emergency running concept to be implemented, which enables the driver of a motor vehicle equipped in this way to reach the nearest workshop even in the event of a failure of the control unit in a kind of emergency operation.

Ein weiterer Vorteil besteht in der Tatsache, dass die Zündsignale von einem Geber abgeleitet werden, der nicht zur Ansteuerung des Steuergerätes dient. Somit erweist sich dieses System auch dann als wirksam, wenn ein Geber für die Haupteingangsgrössen des Steuergerätes ausfällt.Another advantage is the fact that the ignition signals are derived from an encoder that is not used to control the control unit. This system therefore also proves to be effective if an encoder fails for the main input variables of the control unit.

Durch die in den Unteransprüchen aufgeführten Massnahmen sind weitere vorteilhafte Ausbildungen und Verbesserungen der im Hauptanspruch vorgeschlagenen Einrichtung möglich. Insbesondere die einfache Kopplung über eine Diode und einen einfachen Umschalter, erweist sich als besonders einfach und kostengünstig. Dieses Merkmal ist besonders hoch in solchen Fällen zu bewerten, in denen schon existierende Steuergeräte mit einer derartigen Einrichtung nachzurüsten sind.The measures listed in the subclaims make further advantageous developments and improvements of the device proposed in the main claim possible. In particular, the simple coupling via a diode and a simple changeover switch has proven to be particularly simple and inexpensive. This feature is particularly high in those cases in which existing control devices are to be retrofitted with such a device.

Weitere Vorteile der Erfindung ergeben sich aus den in den Unteransprüchen aufgeführten Massnahmen in Verbindung mit der nachfolgenden Beschreibung und der Zeichnung.Further advantages of the invention result from the measures listed in the subclaims in conjunction with the following description and the drawing.

Zeichnungdrawing

Zwei Ausführungsbeispiele der Erfindung sind in Figur 1 und 2 dargestellt. Figur 3 zeigt eine mögliche Ausgestaltung der beiden Ausführungsbeispiele der Figur 1 und Figur 2.Two embodiments of the invention are shown in Figures 1 and 2. FIG. 3 shows a possible embodiment of the two exemplary embodiments in FIGS. 1 and 2.

Beschreibung der AusführungsbeispieleDescription of the embodiments

In Figur 1 ist mit 10 eine Zündspule bezeichnet, die eine Primärwicklung 11, eine Sekundärwicklung sowie einen Eisenkern 13 beinhaltet. Die Primärwicklung 11 ist zwischen die Batteriespannung UB und den Kollektor eines Transistors 14, dessen Emitter auf Massenpotential liegt, geschaltet. Die Basis dieses Transistors 14 wird von einem Zündimpulsgeber 15 angesteuert, der beispielsweise als mechanischer Unterbrecher, Induktionsgeber, Hall-Geber, Wiegand-Geber oder auch als optischer Geber ausgebildet sein kann. Die Sekundärspule 12 der Zündspule 10 ist eingangsseitig an den Verbindungspunkt 16 zwischen Primärspule und Kollektor des Transistors 14 angeschlossen. Ausgangsseitig führen die Hochspannungszündsignale zu einer nicht weiter dargestellten Zündanlage.In FIG. 1, 10 denotes an ignition coil, which contains a primary winding 11, a secondary winding and an iron core 13. The primary winding 11 is connected between the battery voltage U B and the collector of a transistor 14, the emitter of which is at ground potential. The base of this transistor 14 is controlled by an ignition pulse generator 15, which can be designed, for example, as a mechanical interrupter, induction transmitter, Hall sensor, Wiegand sensor or also as an optical sensor. The secondary coil 12 of the ignition coil 10 is connected on the input side to the connection point 16 between the primary coil and the collector of the transistor 14. On the output side, the high-voltage ignition signals lead to an ignition system, which is not shown.

Ein mit der Ziffer 17 bezeichnetes Steuergerät, dem Daten über verschiedene Betriebsparameter, wie der Druck p, die Drehzahl n, die Temperatur 19, Lastinformationen L oder die angesaugte Luft- bzw. eingespritzte Kraftstoffmenge Q zugeführt werden, liefert über eine Leitung 18, einen Schalter 19, der sich in Stellung A befindet, Einspritzimpulse an ein schematisch dargestelltes Einspritzventil 20. Es versteht sich, dass die erfindungsgemässe Einrichtung auch bei Anlagen mit mehreren Einspritzventilen im gleichen Sinne einsetzbar ist. Das Einspritzventil 20 ist ausgangsseitig an die Batteriespannung UB angeschlossen. Für die Schalterstellung des Schalters 19 in Position B liegt eine Verbindung zwischen dem Verbindungspunkt 16 über eine Diode 28 mit dem Einspritzventil 20 vor.A designated by the numeral 17 control unit, the data on various operating parameters, such as the pressure p, n is the rotational speed, the temperature of 1 to 9, load information L or the intake air and injected fuel quantity Q is fed, supplies via a pipe 18, a Switch 19, which is in position A, sends injection pulses to a schematically illustrated injection valve 20. It goes without saying that the device according to the invention can also be used in the same sense in systems with a plurality of injection valves. The injection valve 20 is connected on the output side to the battery voltage U B. For the switch position of the switch 19 in position B, there is a connection between the connection point 16 via a diode 28 and the injection valve 20.

Eine mit 21 bezeichnete Kraftstoffpumpe bezieht ihre Versorgungsspannung UB über einen Schalter 22 und ist mit ihrem anderen Anschluss auf Massepotential gelegt. Der Schalter 22 ist über eine Steuerleitung 23 mit dem Steuergerät 17 verbunden. Der Verbindungspunkt zwischen Kraftstoffpumpe 21 und Schalter 22 kann über eine weitere, durch einen Schalter 24 unterbrochene Leitung ebenfalls auf das Potential der Versorgungsspannung UB gelegt werden. Die Schalter 19 und 24 werden über ein Relais 25 angesteuert, das durch Anlegen der Batteriespannung UB über eine Leitung vom Steuergerät aktiviert wird. Im aktivierten Zustand des Relais 25 befinden sich die Schalter 19 und 24 in der mit A bezeichneten Stellung. Die Ausgangsleitungen des Steuergerätes 17 können über einen Zentralstecker 26 vom Steuergerät getrennt werden.A fuel pump designated 21 receives its supply voltage U B via a switch 22 and is connected to ground potential with its other connection. The switch 22 is connected to the control unit 17 via a control line 23. The connection point between the fuel pump 21 and the switch 22 can be via a further one Switch 24 interrupted line are also placed on the potential of the supply voltage U B. The switches 19 and 24 are controlled by a relay 25, which is activated by applying the battery voltage U B via a line from the control unit. In the activated state of the relay 25, the switches 19 and 24 are in the position labeled A. The output lines of the control device 17 can be separated from the control device via a central plug 26.

Im Normalfall eines störungsfreien Betriebes des Steuergerätes 17 ist das Relais 25 durch Anlegen der Batteriespannung UB über den Zentralstecker 26 aktiviert. Die Einspritzimpulse des Steuergerätes gelangen über die Leitung 18 und den Schalter 19 (in Stellung A) zu den Einspritzventilen. Über die Steuerleitung 23 ist der Schalter 22 geschlossen und die Kraftstoffpumpe 21 liefert über nicht dargestellte Kraftstoffleitungen den Kraftstoff zu den Einspritzventilen 20.In the normal case of trouble-free operation of the control device 17, the relay 25 is activated by applying the battery voltage U B via the central plug 26. The injection pulses from the control unit reach the injection valves via line 18 and switch 19 (in position A). The switch 22 is closed via the control line 23 and the fuel pump 21 supplies the fuel to the injection valves 20 via fuel lines (not shown).

Die Zündung arbeitet unabhängig von der Funktion des Steuergerätes und liefert die entsprechenden Zündimpulse an die Zündkerzen der Brennkraftmaschine, die in diesem Bild nicht dargestellt sind.The ignition works independently of the function of the control unit and delivers the corresponding ignition pulses to the spark plugs of the internal combustion engine, which are not shown in this picture.

Im Falle des Auftretens eines ernsthaften Störfalles des Steuergerätes 17, in dem ein Funktionieren der Brennkraftmaschine nicht gewährleistet ist, lässt sich die Notfahrfunktion dadurch einschalten, dass der Zentralstecker 26 vom Steuergerät abgezogen wird. Bei dieser Massnahme handelt es sich um eine ganz spezielle Ausführungsform; es wäre ebenso denkbar, dass die Ausgangsleitungen des Steuergerätes über einen im Kraftfahrzeug angebrachten Schalter unterbrechbar sind.In the event of a serious malfunction of the control unit 17, in which the internal combustion engine is not guaranteed to function, the emergency drive function can be switched on in that the central plug 26 is removed from the control unit. This measure is a very special embodiment; it would also be conceivable that the output lines of the control device can be interrupted via a switch installed in the motor vehicle.

Auf jeden Fall wird dann Schalter 22 geöffnet, so dass die Kraftstoffpumpe 21 von der Versorgungsspannung agbekoppelt ist. Andererseits schaltet das Relais 25 in seine Ruhestellung, d.h. die beiden Schalter 19 und 24 gelangen in die eingezeichnete Position B. Dies hat zur Folge, dass das Einspritzventil 20 über Schalter 19 (in Position B) sowie die Diode 28 am Verbindungspunkt 16 liegt. Die Spannungsversorgung der Kraftstoffpumpe 21 wird über den zweiten Schalter 24 (in Position B) wieder hergestellt.In any case, switch 22 is then opened so that fuel pump 21 is decoupled from the supply voltage. On the other hand, the relay 25 switches to its rest position, i.e. the two switches 19 and 24 move to the drawn position B. This has the consequence that the injector 20 is located via switch 19 (in position B) and the diode 28 at the connection point 16. The voltage supply to the fuel pump 21 is restored via the second switch 24 (in position B).

Ist der Transistor 14 leitend, d.h., dass sich die Zündanlage in der Phase «induktive Zündenergiespeicherung» befindet, so liegt der Verbindungspunkt 16 annähernd auf Massepotential und das Einspritzventil 20 wird über die leitende Diode 28 aktiviert. Wird der Transistor 14 dagegen von dem Zündimpulsegeber 15 zwecks Erzeugung eines Zündfunkens gesperrt, so treten am Verbindungspunkt 16 hohe positive Spannungen auf, so dass die Diode 28 sperrt und damit das Einspritzventil 20 schliesst. Auf diese Weise werden das Einspritzventil 20 und die Zündkerzen wechselweise angesteuert.If the transistor 14 is conductive, i.e. that the ignition system is in the “inductive ignition energy storage” phase, the connection point 16 is approximately at ground potential and the injection valve 20 is activated via the conductive diode 28. However, if the transistor 14 is blocked by the ignition pulse generator 15 for the purpose of generating an ignition spark, high positive voltages occur at the connection point 16, so that the diode 28 blocks and thus closes the injection valve 20. In this way, the injector 20 and the spark plugs are driven alternately.

Für Ausführungsbeispiele, bei denen der Schalter 22 nicht vom Steuergerät 17 angesteuert, sondern von anderen unabhängigen Komponenten betätigt wird, kann der Schalter 24 entfallen.The switch 24 can be omitted for exemplary embodiments in which the switch 22 is not controlled by the control device 17 but is actuated by other independent components.

Im Ausführungsbeispiel der Figur 2 sind gleiche Komponenten gleich beziffert. Im weiteren werden nur die Abweichungen vom Ausführungsbeispiel der Figur 1 näher erläutert. Die Einspritzimpulse t; bzw. die Lastsignale tp werden, wie gehabt, über den Schalter 19 (in Stellung A) dem Einspritzventil 20 zugeführt. Darüber hinaus liegen diese Signale auch an einem Drehzahlrelais 29 an, mit dem der Schalter 19 betätigt wird. Weiterhin können diesem Drehzahlrelais Startsignal-Informationen von einem Startsignal-Geber 30 zugeführt werden. Der Schalter 22 zur Unterbrechung der Versorgungsspannung wird in diesem Ausführungsbeispiel nicht von dem Steuergerät 17 sondern von einem Drehzahlrelais 31 betätigt, das eingangsseitig an den Verbindungspunkt 16 angeschlossen ist.In the exemplary embodiment in FIG. 2, the same components are numbered the same. Only the deviations from the exemplary embodiment in FIG. 1 are explained in more detail below. The injection pulses t; or the load signals tp, as before, are fed to the injection valve 20 via the switch 19 (in position A). In addition, these signals are also present at a speed relay 29 with which the switch 19 is actuated. Start signal information from a start signal transmitter 30 can also be supplied to this speed relay. In this exemplary embodiment, the switch 22 for interrupting the supply voltage is not actuated by the control unit 17 but by a speed relay 31 which is connected on the input side to the connection point 16.

Diese an sich bekannten Drehzahlrelais 29 und 31 funktionieren in der Weise, dass sie bei Unterschreiten eines bestimmten Wertes der an ihren Eingang anliegenden Impulsfolgefrequenz schalten, d.h. ihre Ausgangsgrösse ändern bzw. den zugeordneten Schalter betätigen. Im einzelnen wird das Relais von einer elektronischen Zeitstufe angesteuert, die entweder als retriggerbare monostabile Kippstufe oder als retriggerbarerTimer ausgeführt ist. Beim Anlegen der Batteriespannung wird die Zeitstufe gesetzt, das Relais zieht für eine bestimmte Zeitdauer an und fällt dann wieder ab, wenn keine Impulse ankommen. Die Zeitdauer wird so gewählt, dass sie grösser ist als der zeitliche Impulsabstand bei der niedersten Drehzahl. Ausserdem wird im Störfall das Relais ebenfalls sofort aktiviert.These speed relays 29 and 31, known per se, function in such a way that they switch when the value falls below a certain value of the pulse repetition frequency applied to their input, i.e. change their output size or press the assigned switch. In particular, the relay is controlled by an electronic time stage, which is designed either as a retriggerable monostable multivibrator or as a retriggerable timer. When the battery voltage is applied, the timer is set, the relay picks up for a certain period of time and then drops again if no pulses arrive. The time period is chosen so that it is greater than the time pulse interval at the lowest speed. In addition, the relay is also activated immediately in the event of a fault.

Bei laufendem Motor wird das Drehzahlrelais von den Zündimpulsen immer erneut getriggert, so dass die Standzeit nicht abläuft und das Relais dauernd angezogen bleibt. Im vorliegenden Ausführungsbeispiel liegt die Schaltschwelle für die Pulsfolgefrequenz in der Gegend um 1 Hz, sie kann jedoch durchaus auch andere, fahrzeugspezifisch angepasste Werte annehmen. Das Drehzahlrelais 31 schaltet aus Sicherheitsgründen die Kraftstoffversorgung der Kraftstoffpumpe 21 bei Zündimpulsfolgen, die den eingestellten Schwellwert unterschreiten, ab.When the engine is running, the speed relay is triggered again and again by the ignition pulses, so that the service life does not expire and the relay remains constantly energized. In the present exemplary embodiment, the switching threshold for the pulse repetition frequency is in the region of 1 Hz, but it can also take on other values adapted to the vehicle. For safety reasons, the speed relay 31 switches off the fuel supply to the fuel pump 21 in the event of firing pulse sequences that fall below the set threshold value.

Ein eventueller Störfall des Steuergerätes 17 wird im vorliegenden Ausführungsbeispiel durch das Drehzahlrelais 29 erkannt. Beim Ausbleiben von Einspritzimpulsen bzw. beim Unterschreiten einer einstellbaren Anzahl von Einspritzimpulsen pro Zeiteinheit schaltet das Drehzahlrelais 29 den Schalter 19 in Position B, so dass auch hier in der gleichen Weise wie im Ausführungsbeispiel der Figur 1 das Einspritzventil 20 über die Diode 28 von den Impulsen der Zündanlage am Verbindungspunkt 16 angesteuert wird. Für den Startfall ist ein Startsignalgeber 30 vorgesehen, der ein Ansprechen des Drehzahlrelais 29 während der Startphase verhindert.A possible malfunction of the control unit 17 is recognized by the speed relay 29 in the present exemplary embodiment. If there are no injection pulses or if the number of injection pulses falls below an adjustable number, the speed relay 29 switches the switch 19 to position B, so that here too, in the same way as in the exemplary embodiment in FIG. 1, the injection valve 20 releases the pulses via the diode 28 the ignition system is controlled at connection point 16. For the start case, a start signal generator 30 is provided which prevents the speed relay 29 from responding during the start phase.

Im Ausführungsbeispiel der Figur 2 geschieht also der Umschaltvorgang auf «Notfahrbetrieb» automatisch, d.h. er wird vom Drehzahlrelais 29 erkannt.In the exemplary embodiment in FIG. 2, the switchover to “emergency driving mode” takes place automatically, i.e. it is recognized by the speed relay 29.

Das Ausführungsbeispiel der Figur 3 dient zu einer aktiven Entkopplung zwischen der Primärspule 11 der Zündspule 10 und dem Einspritzventil 20. Auch in diesem Ausführungsbeispiel werden identische Komponenten mit gleichen Nummern bezeichnet. Die für die Erklärung der Funktionsweise dieses Ausführungsbeispiels nicht wichtigen Komponenten wurden nicht dargestellt, aber es versteht sich, dass diese Anordnung in jedem der vorherigen Ausführungsbeispiele eingesetzt werden kann. Befindet sich Schalter 19 in Stellung B, d.h., es liegt Notfahrbetrieb vor, so ist im vorliegenden Fall das Einspritzventil 20 nicht mehr direkt mit der Diode 28 verbunden. Die Signale der Zündanlage laufen vom Verbindungspunkt 16 über die Diode 28, einen Widerstand 32, die Basis-Kollektor-Strecke eines Transistors 33, die Basis-Kollektor-Strecke eines weiteren Transistors 34 und den Schalter 19 (Stellung B) zum Einspritzventil 20. Der Kollektor des Transistors 33 ist über einen Widerstand 35 mit der Versorgungsspannung UB verbunden, während die Emitter der Transistoren 33 und 34 an Massepotential angeschlossen sind. Diese an sich bekannte Schaltungsanordnung hat den Vorteil, dass die Primärspule 11 der nicht dargestellten Zündimpulse 10 kaum belastet wird und somit eine ausreichende Entkopplung zwischen dem Einspritzventil 20 und der Zündanlage erreicht wird.The exemplary embodiment in FIG. 3 is used for active decoupling between the primary coil 11 of the ignition coil 10 and the injection valve 20. In this exemplary embodiment as well, identical components are identified by the same numbers. The components which are not important for explaining the functioning of this exemplary embodiment have not been shown, but it is understood that this arrangement can be used in any of the previous exemplary embodiments. Switch 19 is in position B, ie there is emergency driving operation before, in the present case the injection valve 20 is no longer directly connected to the diode 28. The signals of the ignition system run from the connection point 16 via the diode 28, a resistor 32, the base-collector path of a transistor 33, the base-collector path of a further transistor 34 and the switch 19 (position B) to the injection valve 20. The The collector of the transistor 33 is connected to the supply voltage U B via a resistor 35, while the emitters of the transistors 33 and 34 are connected to ground potential. This circuit arrangement, which is known per se, has the advantage that the primary coil 11 of the ignition pulses 10 (not shown) is hardly loaded and thus sufficient decoupling between the injection valve 20 and the ignition system is achieved.

Eine alternative Massnahme könnte darin bestehen, dass im Falle des «Notlaufbetriebes» eventuell nur noch die Hälfte der normal betriebenen Einspritzventile angesteuert würde und somit für eine ausreichend zur Verfügung stehende Zündenergie gesorgt wäre.An alternative measure could be that in the case of "emergency operation" only half of the normally operated injection valves would be activated and thus sufficient ignition energy would be provided.

Besonders vorteilhaft erweist sich, im Falle des «Notfahrbetriebes» die Luftzufuhrzur Brennkraftmaschine über etwaige im Ansaugrohr angebrachte Zusatzluftschieber oder Bypässe zu erhöhen. Hierdurch wird eine Anfettung des Luft-Kraftstoff-Gemisches durch die im «Notfahrbetrieb» autretenden Mehrfachspritzer wieder kompensiert, so dass ein gut zündbares Gemisch der Brennkraftmaschine zur Verfügung steht.It proves particularly advantageous to increase the air supply to the internal combustion engine in the case of “emergency operation” via any additional air slides or bypasses fitted in the intake pipe. This compensates for an enrichment of the air-fuel mixture by the multiple splashes occurring in the «emergency driving mode», so that an easily ignitable mixture of the internal combustion engine is available.

Claims (7)

1. Device for fuel metering in a spark-ignition internal combustion engine equipped with an injection system, having a control unit which generates injection pulses for triggering injection valves at least as a function of the rotational speed of the internal combustion engine, in which - in the case of a fault in the control device (17) - the system can be switched over to triggering of the injection valves (20) by means of injection pulses derived from the ignition system of the internal combustion engine, characterized in that the duration of the current flow phase of the injection valves is directly determined by the switching behaviour of a transistor connected in series with the low tension winding of the ignition coil.
2. Device according to Claim 1, characterized in that the ignition system of the internal combustion engine is designed as a current-controlled transistor ignition system.
3. Device according to Claim 1 or 2, characterized in that the injection pulse is fed from an ignition coil (10) to the injection valve (20) via a valve element designed as a diode (28).
4. Device according to Claim 3, characterized in that a transistor combination (33, 34) designed as an impedance converter is connected between valve element (diode 28) and injection valve (20).
5. Device according to at least one of the preceding claims, characterized in that the control unit is connected by means of a central plug to the electrical devices to be controlled and that the system is switched over by extracting the central plug (26).
6. Device according to at least one of the Claims 1 to 4, characterized in that the system is switched over by means of a rotational speed relay (29), sensitive to the injection pulse sequence, when the sequence becomes less than a specified minimum value.
7. Device according to Claim 6, characterized in that the rotational speed relay (29) is put out of operation during starting.
EP84902912A 1983-09-08 1984-07-25 Fuel metering device for an internal combustion engine Expired EP0155273B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84902912T ATE31781T1 (en) 1983-09-08 1984-07-25 DEVICE FOR FUEL METERING IN AN INTERNAL ENGINE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3332399 1983-09-08
DE3332399A DE3332399C1 (en) 1983-09-08 1983-09-08 Device for metering fuel in an externally ignited internal combustion engine equipped with an injection system

Publications (2)

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EP0155273A1 EP0155273A1 (en) 1985-09-25
EP0155273B1 true EP0155273B1 (en) 1988-01-07

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EP84902912A Expired EP0155273B1 (en) 1983-09-08 1984-07-25 Fuel metering device for an internal combustion engine

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US (1) US4653450A (en)
EP (1) EP0155273B1 (en)
JP (1) JPH0654098B2 (en)
BR (1) BR8407061A (en)
DE (2) DE3332399C1 (en)
IT (1) IT1176637B (en)
WO (1) WO1985001083A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0347446A (en) * 1989-07-12 1991-02-28 Mitsubishi Electric Corp Ignition and fuel system backup device
US5103792A (en) * 1990-10-16 1992-04-14 Stanadyne Automotive Corp. Processor based fuel injection control system
JPH04232361A (en) * 1990-12-28 1992-08-20 Kokusan Denki Co Ltd Injector drive for internal combustion engine and drive device
US6119670A (en) * 1997-08-29 2000-09-19 Autotronic Controls Corporation Fuel control system and method for an internal combustion engine
JP2002364435A (en) * 2001-06-01 2002-12-18 Kawasaki Heavy Ind Ltd Fuel injection type engine

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Publication number Priority date Publication date Assignee Title
US3834361A (en) * 1972-08-23 1974-09-10 Bendix Corp Back-up fuel control system
DE2503108C3 (en) * 1975-01-25 1979-09-20 Robert Bosch Gmbh, 7000 Stuttgart Electrically controlled fuel injection system with ignition-controlled trigger stage for an internal combustion engine
DE2838619A1 (en) * 1978-09-05 1980-03-20 Bosch Gmbh Robert DEVICE FOR CONTROLLING OPERATING PARAMETER DEPENDENT AND REPEATING PROCESSES FOR INTERNAL COMBUSTION ENGINES
DE2945543A1 (en) * 1979-11-10 1981-05-21 Robert Bosch Gmbh, 7000 Stuttgart DEVICE FOR CONTROLLING OPERATING PARAMETER DEPENDENT AND REPEATING PROCESSES FOR INTERNAL COMBUSTION ENGINES
JPS56135201A (en) * 1980-03-24 1981-10-22 Nissan Motor Co Ltd Pulse generator for engine control
JPS57181939A (en) * 1981-05-06 1982-11-09 Hitachi Ltd Fuel feed method for automobile engine
JPS58117326A (en) * 1982-01-05 1983-07-12 Nissan Motor Co Ltd Preventive device for danger for automobile
JPS58106564U (en) * 1982-01-13 1983-07-20 日産自動車株式会社 Internal combustion engine ignition control device
JPS58144664A (en) * 1982-02-23 1983-08-29 Nippon Denso Co Ltd Controlling apparatus of internal-combustion engine
JPS592102A (en) * 1982-06-29 1984-01-07 Oki Electric Ind Co Ltd Operation controlling system of internal combustion engine

Also Published As

Publication number Publication date
JPH0654098B2 (en) 1994-07-20
DE3332399C1 (en) 1985-02-28
WO1985001083A1 (en) 1985-03-14
IT8422501A0 (en) 1984-09-03
DE3468482D1 (en) 1988-02-11
US4653450A (en) 1987-03-31
EP0155273A1 (en) 1985-09-25
JPS60502162A (en) 1985-12-12
IT1176637B (en) 1987-08-18
BR8407061A (en) 1985-08-13

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