EP0482239A1 - Engine injection system - Google Patents

Engine injection system Download PDF

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Publication number
EP0482239A1
EP0482239A1 EP90120421A EP90120421A EP0482239A1 EP 0482239 A1 EP0482239 A1 EP 0482239A1 EP 90120421 A EP90120421 A EP 90120421A EP 90120421 A EP90120421 A EP 90120421A EP 0482239 A1 EP0482239 A1 EP 0482239A1
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EP
European Patent Office
Prior art keywords
tank ventilation
tlmax
correction device
injection system
maximum deviation
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Granted
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EP90120421A
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German (de)
French (fr)
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EP0482239B1 (en
Inventor
Stefan Dr.-Ing. Krebs
Michael Dipl.-Ing. Föhr (FH)
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Siemens AG
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Siemens AG
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Priority to EP19900120421 priority Critical patent/EP0482239B1/en
Priority to DE90120421T priority patent/DE59004362D1/en
Publication of EP0482239A1 publication Critical patent/EP0482239A1/en
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Publication of EP0482239B1 publication Critical patent/EP0482239B1/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
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/003—Adding fuel vapours, e.g. drawn from engine fuel reservoir
    • F02D41/0042—Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
    • 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
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir

Definitions

  • the invention relates to a fuel injection system for an internal combustion engine according to the preamble of claim 1.
  • a control unit determines a basic quantity depending on the load and speed. This basic quantity is corrected by a correction device present in the control unit with the aid of a superimposed lambda control.
  • the system also has a closed tank ventilation system that prevents fuel vapors from entering the atmosphere. For this purpose, these fuel vapors are retained in a store.
  • the memory is connected to the intake tract of the internal combustion engine via a feed line, so that fuel vapors emerging therefrom are fed to the engine for combustion.
  • the influence of the mixture ratios by the tank ventilation system is not known. In particular, it is not known when additional fuel reaches the intake tract from the accumulator and in what quantity.
  • the superimposed lambda control recognizes a mixture deviation caused thereby, but cannot determine its cause. In particular, it cannot be differentiated whether the mixture deviation requires a lambda adaptation due to longer-lasting disturbing influences or whether it only represents a brief disturbance due to the influence of the tank ventilation system. In this case, no lambda adaptation would be necessary, since after the short-term disturbance has subsided, it would have to be reversed.
  • the object of the present invention is therefore to distinguish a need for lambda adaptation from the need to correct the influence of the tank ventilation system and to specify such a correction.
  • the solution according to the invention provides for a tank ventilation map to be stored which characterizes the characteristic of the tank ventilation system. Maximum deviation values are stored in it depending on the load and the speed. Depending on the operating point, these deviation values represent a deviation of the fuel quantity from the basic quantity caused by the tank ventilation. They apply in the event that the accumulator is fully loaded with fuel.
  • the correction device uses the averaged control signal from the lambda control device to determine whether and to what extent such an influence is really present.
  • the control signal does not result in a deviation in a pressure-guided system which is insensitive to "leakage air". In other systems there is a slight lean shift due to the additional air. If, on the other hand, the memory is fully loaded, the deviation indicated by the control signal becomes equal to the maximum deviation value read from the tank ventilation map. In all cases between these two extremes, the ratio of the averaged control signal and the maximum deviation value from the tank ventilation map shows the degree of loading of the storage tank. The correction device calculates this degree of loading and stores it.
  • the degree of loading of the accumulator determined in this way can now be used in the following calculations of the injection quantity for the correction of the influence of the tank ventilation.
  • the maximum deviation value is read out from the tank ventilation map, depending on the operating point.
  • the correction device thus receives a correction value for correcting the basic quantity, which takes into account the influence of the tank ventilation system.
  • FIG. 1 An internal combustion engine is designated 1, an intake tract 11 and an exhaust tract 12.
  • control unit 4 In the intake tract 11, a throttle valve actuated by the driver is arranged for filling control, and a control unit 4 effects an injection quantity TI of fuel via an injection system, which is only indicated in the drawing. To determine this injection quantity TI, control unit 4 receives as input variables are a throttle valve angle a from a corresponding position sensor, a speed n of the internal combustion engine 1 from a speed sensor and a probe signal from a lambda probe 3 arranged in the exhaust tract 12.
  • the control unit 4 determines a basic quantity TIG from the throttle valve angle and the rotational speed n from a map.
  • a signal corresponding to the intake manifold pressure in the intake tract 11 or a signal from an air mass meter could also be used.
  • a correction device is provided in the control device 4, which corrects the basic quantity TIG with the aid of a lambda control device.
  • a tank ventilation system consists of a tank 2, an activated carbon store 21 and a feed line 22. Fuel vapors generated in the tank 2 are stored in the activated carbon store 21. This is open on one side to the atmosphere and on the other hand connected to the intake tract 11 via the feed line 22. Depending on the negative pressure prevailing in the intake tract 11 in connection with the throttle valve position and the loading of the activated carbon filter 21 with fuel, additional fuel therefore enters the internal combustion engine 1.
  • a tank ventilation map according to FIG. 2 is provided.
  • Maximum deviation values Tlmax are stored in it depending on the input variables throttle valve angle a and speed n. These deviation values are determined experimentally for a specific internal combustion engine 1 and characterize the influence of the tank ventilation system at each operating point on the assumption that the activated carbon store 21 is 100% loaded with fuel vapor.
  • the maximum deviation values Tlmax are related to the corresponding basic quantity TIG, that is to say they mean a percentage or a factor that defines the deviation from the basic quantity TIG.
  • the maximum deviation values Tlmax are shown in FIG. 2 on the basis of a spatial envelope surface.
  • the correction device cyclically determines a degree of loading V of the activated carbon store 21 according to FIG. 3.
  • a first step S1 the values for the throttle valve angle a and the speed n are read.
  • step S2 the corresponding maximum deviation value Tlmax is then read out from the tank ventilation map.
  • step 3 This is followed by a query in step 3 as to whether the maximum deviation value Tlmax is greater than a limit value GW.
  • This limit value GW is shown in FIG. 2. Its height is determined experimentally. If the maximum deviation value Tlmax is below this limit value GW, there is either no influence at all by the tank ventilation system or it is too small. Accordingly, if there is no such influence, the correction device releases a conventional lambda adaptation. If, on the other hand, the limit value GW is exceeded, the tank ventilation system can have an influence and it is assumed that lambda deviations are then determined solely by the tank ventilation. Accordingly, every lambda adaptation is blocked.
  • step S4 the correction device then determines an averaged control signal R from the current and previous output signals of the lambda control device. Then in step S5 the degree of loading V of the activated carbon filter 21 is calculated from the quotient of the averaged control signal R and the maximum deviation value Tlmax.
  • FIG. 4 shows the correction of the current calculation of the injection time TI for the individual cylinders.
  • step S7 the values for the throttle valve angle a and the speed n are read.
  • step S8 the basic quantity TIG results from a map.
  • step S9 the maximum deviation value Tlmax is determined from the tank ventilation map as in FIG. 2.
  • step S10 there is then a correction value TIK for correcting the influence of the tank ventilation from this maximum deviation value Tlmax multiplied by the loading degree V, which indicates the actual loading of the activated carbon filter 21.
  • the injection quantity TI which is injected into the next cylinder, is the product of the basic quantity TIG, the correction value TIK and a further correction value TI X.
  • This further correction value TI results from the normal lambda adaptations and corrections not considered here, and their calculation takes place if it was recognized in step S3 from FIG. 3 that there is no influence of the tank ventilation system.
  • a shut-off valve can be provided in the feed line 22, which is indicated in FIG. 1 by the dashed line.
  • a pressure-controlled and / or thermostat-controlled valve serves as a shut-off valve.
  • the pressure-controlled valve serves to prevent the influence of the tank ventilation at full load and with the engine stopped, i.e. when the intake manifold pressure is close to or equal to the atmospheric pressure. In this case, fuel vapor could otherwise escape into the atmosphere via the intake manifold or the activated carbon storage.
  • the thermostatically controlled valve serves to prevent the influence of the tank ventilation when the engine is cold or when it is warming up, since in these operating states it is not desired to influence the mixture.

Abstract

In an injection system the influence of a tank venting system is detected and corrected by way of a tank venting characteristic. This contains maximum tolerances (TImax), which are analysed on the basis of averaged control signals R<2bL> from a lambda control device, so that a correction value TIK derived from these takes account of the true degree of loading V of the tank venting system. <IMAGE>

Description

Die Erfindung betrifft ein Kraftstoffeinspritzsystem für eine Brennkraftmaschine gemäß Oberbegriff von Anspruch 1.The invention relates to a fuel injection system for an internal combustion engine according to the preamble of claim 1.

Dabei ist ein Steuergerät vorgesehen, das eine Grundmenge abhängig von Last und Drehzahl ermittelt. Diese Grundmenge wird durch eine im Steuergerät vorhandene Korrektureinrichtung mit Hilfe einer überlagerten Lambda-Regelung korrigiert.A control unit is provided that determines a basic quantity depending on the load and speed. This basic quantity is corrected by a correction device present in the control unit with the aid of a superimposed lambda control.

Das System weist weiterhin ein geschlossenes Tankentlüftungssystem auf, das verhindert, daß Kraftstoffdämpfe in die Atmosphäre gelangen. Dazu werden diese Kraftstoffdämpfe in einem Speicher zurückgehalten. Der Speicher ist mit dem Ansaugtrakt der Brennkraftmaschine über eine Zuleitung verbunden, so daß daraus austretende Kraftstoffdämpfe der Maschine zur Verbrennung zugeführt werden.The system also has a closed tank ventilation system that prevents fuel vapors from entering the atmosphere. For this purpose, these fuel vapors are retained in a store. The memory is connected to the intake tract of the internal combustion engine via a feed line, so that fuel vapors emerging therefrom are fed to the engine for combustion.

Die Beeinflussung der Gemischverhältnisse durch das Tankentlüftungssystem ist nicht bekannt. Insbesondere ist nicht bekannt, wann zusätzlicher Kraftstoff aus dem Speicher in den Ansaugtrakt gelangt und in welcher Menge. Die überlagerte Lambda-Regelung erkennt zwar eine dadurch bewirkte Gemischabweichung, kann aber nicht deren Ursache feststellen. Dabei ist insbesondere nicht zu unterscheiden, ob die Gemischabweichung aufgrund von längerwirkenden Störeinflüssen eine Lambda-Adaption nötig macht, oder aufgrund des Einflusses des Tankentlüftungssystems nur eine kurzzeitige Störung darstellt. In diesem Fall wäre keine Lambda-Adaption nötig, da nach Abklingen der kurzzeitigen Störung diese wieder rückgängig gemacht werden müßte.The influence of the mixture ratios by the tank ventilation system is not known. In particular, it is not known when additional fuel reaches the intake tract from the accumulator and in what quantity. The superimposed lambda control recognizes a mixture deviation caused thereby, but cannot determine its cause. In particular, it cannot be differentiated whether the mixture deviation requires a lambda adaptation due to longer-lasting disturbing influences or whether it only represents a brief disturbance due to the influence of the tank ventilation system. In this case, no lambda adaptation would be necessary, since after the short-term disturbance has subsided, it would have to be reversed.

Die Aufgabe der vorliegenden Erfindung liegt daher darin, einen Lambda-Adaptionsbedarf von der Notwendigkeit zur Korrektur des Einflusses des Tankentlüftungssystems zu unterscheiden und eine solche Korrektur anzugeben.The object of the present invention is therefore to distinguish a need for lambda adaptation from the need to correct the influence of the tank ventilation system and to specify such a correction.

Die erfindungsgemäße Lösung ist in Anspruch 1 gekennzeichnet. Vorteilhafte Weiterbildungen der Erfindung finden sich in den Unteransprüchen.The solution according to the invention is characterized in claim 1. Advantageous developments of the invention can be found in the subclaims.

Die erfindungsgemäße Lösung sieht vor, ein Tankentlüftungskennfeld abzuspeichern, das die Charakteristik des Tankentlüftungssystems kennzeichnet. Darin sind abhängig von der Last und der Drehzahl maximale Abweichwerte abgelegt. Diese Abweichwerte stellen betriebspunktabhängig eine durch die Tankentlüftung bewirkte Abweichung der Kraftstoffmenge bezogen auf die Grundmenge dar. Sie gelten für den Fall, daß der Speicher voll mit Kraftstoff beladen ist.The solution according to the invention provides for a tank ventilation map to be stored which characterizes the characteristic of the tank ventilation system. Maximum deviation values are stored in it depending on the load and the speed. Depending on the operating point, these deviation values represent a deviation of the fuel quantity from the basic quantity caused by the tank ventilation. They apply in the event that the accumulator is fully loaded with fuel.

Anhand dieses Tankentlüftungskennfelds wird entschieden, ob ein Korrekturbedarf aufgrund der Tankentlüftung nötig ist. Dies ist dann der Fall, wenn der ausgelesene Abweichwert einen Grenzwert übersteigt. Dieser Grenzwert ist so gewählt, daß geringfügige anderweitige Störeinflüsse nicht fälschlicherweise eine Tankentlüftungskorrektur auslösen. Ist der Abweichwert also größer als der Grenzwert, so ist ein Einfluß des Tankentlüftungssystems möglich. Die Korrektureinrichtung stellt dann anhand des gemittelten Regelsignals von der Lambda-Regeleinrichtung fest, ob und in welchem Maße ein solcher Einfluß wirklich vorhanden ist.On the basis of this tank ventilation map, a decision is made as to whether a correction is necessary due to the tank ventilation. This is the case if the deviation value read out exceeds a limit value. This limit value is selected so that minor other interference does not erroneously trigger a tank ventilation correction. If the deviation value is greater than the limit value, the tank ventilation system can have an influence. The correction device then uses the averaged control signal from the lambda control device to determine whether and to what extent such an influence is really present.

Ist der Speicher beispielsweise vollständig leer, so ergibt das Regelsignal keine Abweichung bei einem druckgeführten System, das gegen "Leckluft" unempfindlich ist. Bei anderen Systemen ergibt sich eine geringfügige Magerverschiebung durch die Zusatzluft. Ist der Speicher dagegen voll beladen, so wird die durch das Regelsignal angezeigte Abweichung gleich dem aus dem Tankentlüftungskennfeld ausgelesenen maximalen Abweichwert. In allen Fällen zwischen diesen beiden Extremen gibt dann das Verhältnis aus dem gemittelten Regelsignal und dem maximalen Abweichwert aus dem Tankentlüftungskennfeld den Beladungsgrad des Speichers an. Die Korrektureinrichtung berechnet diesen Beladungsgrad und speichert ihn ab.If the memory is completely empty, for example, the control signal does not result in a deviation in a pressure-guided system which is insensitive to "leakage air". In other systems there is a slight lean shift due to the additional air. If, on the other hand, the memory is fully loaded, the deviation indicated by the control signal becomes equal to the maximum deviation value read from the tank ventilation map. In all cases between these two extremes, the ratio of the averaged control signal and the maximum deviation value from the tank ventilation map shows the degree of loading of the storage tank. The correction device calculates this degree of loading and stores it.

Der so ermittelte Beladungsgrad des Speichers kann nun bei folgenden Berechnungen der Einspritzmenge für die Korrektur des Einflusses der Tankentlüftung herangezogen werden. Dazu wird bei jeder Berechnung der Einspritzmenge wiederum der maximale Abweichwert betriebspunktabhängig aus dem Tankentlüftungskennfeld ausgelesen. Um die wirkliche Beladung des Speichers zu berücksichtigen wird er mit dem Beladungsgrad multipliziert. Die Korrektureinrichtung erhält so einen Korrekturwert zur Korrektur der Grundmenge, der den Einfluß des Tankentlüftungssystems berücksichtigt.The degree of loading of the accumulator determined in this way can now be used in the following calculations of the injection quantity for the correction of the influence of the tank ventilation. For each calculation of the injection quantity, the maximum deviation value is read out from the tank ventilation map, depending on the operating point. To take into account the actual loading of the storage tank, it is multiplied by the loading level. The correction device thus receives a correction value for correcting the basic quantity, which takes into account the influence of the tank ventilation system.

Die Erfindung wird anhand der Figuren näher erläutert. Dabei zeigen:

  • Figur 1 ein vereinfachtes Blockschaltbild eines erfindungsgemäßen Kraftstoffeinspritzsystems,
  • Figur 2 eine Darstellung zur Veranschaulichung eines Tankentlüftungskennfelds,
  • Figur 3 ein Flußdiagramm für die Berechnung eines Beladungsgrades und
  • Figur 4 ein Flußdiagramm für die Berechnung einer Einspritzmenge.
The invention is illustrated by the figures. Show:
  • FIG. 1 shows a simplified block diagram of a fuel injection system according to the invention,
  • FIG. 2 shows an illustration to illustrate a tank ventilation map,
  • Figure 3 is a flow chart for the calculation of a degree of loading and
  • Figure 4 is a flow chart for the calculation of an injection quantity.

In Figur 1 ist ein Kraftstoffeinspritzsystem dargestellt. Darin ist eine Brennkraftmaschine mit 1, ein Ansaugtrakt mit 11 und ein Abgastrakt mit 12 bezeichnet.A fuel injection system is shown in FIG. An internal combustion engine is designated 1, an intake tract 11 and an exhaust tract 12.

Im Ansaugtrakt 11 ist eine vom Fahrer betätigte Drosselklappe zur Füllungssteuerung angeordnet und ein Steuergerät 4 bewirkt über ein in der Zeichnung nur angedeutetes Einspritzsystem eine Einspritzmenge TI an Kraftstoff. Zur Bestimmung dieser Einspritzmenge TI erhält das Steuergerät 4 als Eingangsgrößen einen Drosselklappenwinkel a von einem entsprechenden Positionsgeber, eine Drehzahl n der Brennkraftmaschine 1 von einem Drehzahlgeber und ein Sondensignal von einer im Abgastrakt 12 angeordneten Lambda-Sonde 3.In the intake tract 11, a throttle valve actuated by the driver is arranged for filling control, and a control unit 4 effects an injection quantity TI of fuel via an injection system, which is only indicated in the drawing. To determine this injection quantity TI, control unit 4 receives as input variables are a throttle valve angle a from a corresponding position sensor, a speed n of the internal combustion engine 1 from a speed sensor and a probe signal from a lambda probe 3 arranged in the exhaust tract 12.

Das Steuergerät 4 bestimmt aus dem Drosselklappenwinkel und der Drehzahl n aus einem Kennfeld eine Grundmenge TIG. Anstelle des Drosselklappenwinkels a als Maß für die Last der Brennkraftmaschine 1 könnte auch ein Signal entsprechend dem Saugrohrdruck im Ansaugtrakt 11 oder ein Signal von einem Luftmassenmesser verwendet werden.The control unit 4 determines a basic quantity TIG from the throttle valve angle and the rotational speed n from a map. Instead of the throttle valve angle a as a measure of the load of the internal combustion engine 1, a signal corresponding to the intake manifold pressure in the intake tract 11 or a signal from an air mass meter could also be used.

Im Steuergerät 4 ist eine Korrektureinrichtung vorgesehen, die mit Hilfe einer Lambda-Regeleinrichtung die Grundmenge TIG korrigiert.A correction device is provided in the control device 4, which corrects the basic quantity TIG with the aid of a lambda control device.

Ein Tankentlüfungssystem besteht aus einem Tank 2, einem Aktivkohlespeicher 21 und einer Zuleitung 22. Im Tank 2 entstehende Kraftstoffdämpfe werden in dem Aktivkohlespeicher 21 gespeichert. Dieser ist einseitig zur Atmosphäre hin offen und andererseits über die Zuleitung 22 mit dem Ansaugtrakt 11 verbunden. Je nach dem im Ansaugtrakt 11 herrschenden Unterdruck in Verbindung mit der Drosselklappenstellung und der Beladung des Aktivkohlefilters 21 mit Kraftstoff gelangt daher zusätzlicher Kraftstoff in die Brennkraftmaschine 1.A tank ventilation system consists of a tank 2, an activated carbon store 21 and a feed line 22. Fuel vapors generated in the tank 2 are stored in the activated carbon store 21. This is open on one side to the atmosphere and on the other hand connected to the intake tract 11 via the feed line 22. Depending on the negative pressure prevailing in the intake tract 11 in connection with the throttle valve position and the loading of the activated carbon filter 21 with fuel, additional fuel therefore enters the internal combustion engine 1.

Zur Korrektur dieses Einflusses auf die Gemischverhältnisse ist ein Tankentlüftungskennfeld gemäß Figur 2 vorgesehen. Darin sind abhängig von den Eingangsgrößen Drosselklappenwinkel a und Drehzahl n maximale Abweichwerte Tlmax abgelegt. Diese Abweichwerte werden experimentiell für eine bestimmte Brennkraftmaschine 1 ermittelt und charakterisieren in jedem Betriebspunkt den Einfluß des Tankentlüftungssystem unter der Annahme, daß der Aktivkohlespeicher 21 zu 100 % mit Kraftstoffdampf beladen ist. Die maximalen Abweichwerte Tlmax sind in jedem Betriebspunkt bezogen auf die entsprechende Grundmenge TIG, bedeuten also quasi eine Prozentzahl oder einen Faktor, der die Abweichung von der Grundmenge TIG festlegt. Zur Veranschaulichung sind die maximalen Abweichwerte Tlmax in Figur 2 anhand einer räumlichen Hüllfläche dargestellt.To correct this influence on the mixture ratios, a tank ventilation map according to FIG. 2 is provided. Maximum deviation values Tlmax are stored in it depending on the input variables throttle valve angle a and speed n. These deviation values are determined experimentally for a specific internal combustion engine 1 and characterize the influence of the tank ventilation system at each operating point on the assumption that the activated carbon store 21 is 100% loaded with fuel vapor. At each operating point, the maximum deviation values Tlmax are related to the corresponding basic quantity TIG, that is to say they mean a percentage or a factor that defines the deviation from the basic quantity TIG. For illustration purposes, the maximum deviation values Tlmax are shown in FIG. 2 on the basis of a spatial envelope surface.

Zur Durchführung der Korrektur bestimmt die Korrektureinrichtung zyklisch einen Beladungsgrad V des Aktivkohlespeichers 21 gemäß Figur 3. In einem ersten Schritt S1 werden die Werte für den Drosselklappenwinkel a und die Drehzahl n eingelesen. Im Schritt S2 wird dann der entsprechende maximale Abweichwert Tlmax aus dem Tankentlüfungskennfeld ausgelesen.To carry out the correction, the correction device cyclically determines a degree of loading V of the activated carbon store 21 according to FIG. 3. In a first step S1, the values for the throttle valve angle a and the speed n are read. In step S2, the corresponding maximum deviation value Tlmax is then read out from the tank ventilation map.

Darauf folgt eine Abfrage im Schritt 3, ob der maximale Abweichwert Tlmax größer einem Grenzwert GW ist. Dieser Grenzwert GW ist in Figur 2 eingezeichnet. Seine Höhe ist experimentiell bestimmt. Liegt der maximale Abweichwert Tlmax unter diesem Grenzwert GW, so ist ein Einfluß durch das Tankentlüfungssystem entweder gar nicht vorhanden oder zu gering. Liegt also dementsprechend kein solcher Einfluß vor, so gibt die Korrektureinrichtung eine übliche Lambda-Adaption frei. Ist der Grenzwert GW dagegen überschritten, so ist ein Einfluß des Tankentlüftungssystems möglich und es wird angenommen, daß dann Lambda-Abweichungen allein durch die Tankentlüftung bestimmt sind. Dementsprechend wird jede Lambda-Adaption gesperrt.This is followed by a query in step 3 as to whether the maximum deviation value Tlmax is greater than a limit value GW. This limit value GW is shown in FIG. 2. Its height is determined experimentally. If the maximum deviation value Tlmax is below this limit value GW, there is either no influence at all by the tank ventilation system or it is too small. Accordingly, if there is no such influence, the correction device releases a conventional lambda adaptation. If, on the other hand, the limit value GW is exceeded, the tank ventilation system can have an influence and it is assumed that lambda deviations are then determined solely by the tank ventilation. Accordingly, every lambda adaptation is blocked.

Im Schritt S4 ermittelt die Korrektureinrichtung dann ein gemitteltes Regelsignal R aus dem aktuellen und vorhergehenden Ausgangssignalen der Lambda-Regeleinrichtung. Dann wird im Schritt S5 der Beladungsgrad V des Aktivkohlefilters 21 aus dem Quotienten des gemittelten Regelsignals R und des maximalen Abweichwerts Tlmax berechnet.In step S4, the correction device then determines an averaged control signal R from the current and previous output signals of the lambda control device. Then in step S5 the degree of loading V of the activated carbon filter 21 is calculated from the quotient of the averaged control signal R and the maximum deviation value Tlmax.

Die Figur 4 zeigt schließlich die Korrektur der laufenden Berechnung der Einspritzzeit TI für die einzelnen Zylinder. Im Schritt S7 werden die Werte für den Drosselklappenwinkel a und die Drehzahl n eingelesen. Damit ergibt sich im Schritt S8 aus einem Kennfeld die Grundmenge TIG.Finally, FIG. 4 shows the correction of the current calculation of the injection time TI for the individual cylinders. In step S7, the values for the throttle valve angle a and the speed n are read. In step S8, the basic quantity TIG results from a map.

Im Schritt S9 wird der maximale Abweichwert Tlmax aus dem Tankentlüftungskennfeld wie in Figur 2 bestimmt. Im Schritt S10 ergibt sich dann ein Korrekturwert TIK zur Korrektur des Einflusses der Tankentlüfung aus diesem maximalen Abweichwert Tlmax multipliziert mit dem Beladungsgrad V, der die wirkliche Beladung des Aktivkohlefilters 21 angibt. Die Einspritzmenge TI schließlich, die in den nächstfolgenden Zylinder eingespritzt wird, ist dann das Produkt aus der Grundmenge TIG, dem Korrekturwert TIK und einem weiteren Korrekturwert TI X. Dieser weitere Korrekturwert TI resultiert aus hier nicht betrachteten üblichen Lambda-Adaptionen und Korrekturen, deren Berechnung erfolgt, wenn im Schritt S3 aus Figur 3 erkannt wurde, daß kein Einfluß des Tankentlüftungssystems vorliegt.In step S9, the maximum deviation value Tlmax is determined from the tank ventilation map as in FIG. 2. In step S10 there is then a correction value TIK for correcting the influence of the tank ventilation from this maximum deviation value Tlmax multiplied by the loading degree V, which indicates the actual loading of the activated carbon filter 21. Finally, the injection quantity TI, which is injected into the next cylinder, is the product of the basic quantity TIG, the correction value TIK and a further correction value TI X. This further correction value TI results from the normal lambda adaptations and corrections not considered here, and their calculation takes place if it was recognized in step S3 from FIG. 3 that there is no influence of the tank ventilation system.

In der Zuleitung 22 kann ein Absperrventil vorgesehen sein, was in Figur 1 durch die gestrichelte Linie angedeutet ist. Als Absperrventil dient ein druckgesteuertes und/oder thermostatgesteuertes Ventil. Das druckgesteuerte Ventil dient zur Verhinderung des Tankentlüftungseinflusses bei Vollast und bei stehendem Motor, also wenn der Saugrohrdruck nahe oder gleich dem Atmosphärendruck ist. In diesem Fall könnte sonst über das Saugrohr oder über den Aktivkohlespeicher Kraftstoffdampf in die Atmosphäre entweichen.A shut-off valve can be provided in the feed line 22, which is indicated in FIG. 1 by the dashed line. A pressure-controlled and / or thermostat-controlled valve serves as a shut-off valve. The pressure-controlled valve serves to prevent the influence of the tank ventilation at full load and with the engine stopped, i.e. when the intake manifold pressure is close to or equal to the atmospheric pressure. In this case, fuel vapor could otherwise escape into the atmosphere via the intake manifold or the activated carbon storage.

Das thermostastgesteuerte Ventil dient zur Verhinderung des Tankentlüftungseinflusses bei kaltem Motor oder im Warmlauf, da in diesen Betriebszuständen keine Beeinflussung des Gemisches gewünscht ist.The thermostatically controlled valve serves to prevent the influence of the tank ventilation when the engine is cold or when it is warming up, since in these operating states it is not desired to influence the mixture.

Claims (4)

1. Kraftstoffeinspritzsystem für eine Brennkraftmaschine mit einem Steuergerät (4) zur Bestimmung der Einspritzmenge (TI), das eine Grundmenge (TIG) abhängig von Last und Drehzahl (n) ermittelt,
das eine Korrektureinrichtung enthält mit einer Lambda-Regeleinrichtung, deren gemitteltes Regelsignal (R x ) die Abweichung von der Grundmenge (TIG) darstellt, die dementsprechend korrigiert die Einspritzmenge (TI) ergibt, mit einem geschlossenen Tankentlüftungssystem, das Kraftstoffdämpfe in einem Speicher zwischenspeichert, der mit dem Ansaugtrakt über eine Zuleitung (4) verbunden ist,
dadurch gekennzeichnet,
daß in der Korrektureinrichtung ein Tankentlüftungskennfeld abgelegt ist, das maximale Abweichwerte (Tlmax) abhängig von Last und Drehzahl (n) enthält, die die durch die Tankentlüftung bei mit Kraftstoff voll beladenem Speicher bewirkte Abweichung bezogen auf die Grundmenge (TIG) im jeweiligen Betriebspunkt darstellen,
daß die Korrektureinrichtung, wenn der maximale Abweichwert (Tlmax) einen Grenzwert (GW) übersteigt, aus dem gemittelten Regelsignal (R x ) und dem maximalen Abweichwert (Tlmax) einen Beladungsgrad (V) des Speichers durch Verhältnisbildung ermittelt und abspeichert und
daß die Korrektureinrichtung bei folgenden Berechnungen der Einspritzmenge (TI) einen Korrekturwert (TIK) berücksichtigt, der aus dem Tankentlüftungskennfeld ausgelesen und mit dem Beladungsgrad (V) bewertet ist.1. fuel injection system for an internal combustion engine with a control unit (4) for determining the injection quantity (TI), which determines a basic quantity (TIG) as a function of load and speed (n),
which contains a correction device with a lambda control device, whose averaged control signal (R x) represents the deviation from the basic quantity (TIG), which accordingly corrects the injection quantity (TI), with a closed tank ventilation system that temporarily stores fuel vapors in a memory that is connected to the intake tract via a feed line (4),
characterized,
that a tank ventilation map is stored in the correction device, which contains maximum deviation values (Tlmax) depending on the load and speed (n), which represent the deviation caused by the tank ventilation when the accumulator is fully loaded with fuel in relation to the basic quantity (TIG) at the respective operating point,
that the correction device, if the maximum deviation value (Tlmax) exceeds a limit value (GW), from the averaged control signal (R x) and the maximum deviation value (Tlmax) determines and stores a loading degree (V) of the memory by forming the ratio and
that the correction device takes into account a correction value (TIK) in the following calculations of the injection quantity (TI), which is read from the tank ventilation map and evaluated with the degree of loading (V). 2. Kraftstoffeinspritzsystem nach Anspruch 1,
dadurch gekennzeichnet,
daß die Korrektureinrichtung, wenn der maximale Abweichwert Tlmax kleiner ist als der Grenzwert GW bei entsprechenden Betriebsbedingungen eine Lambda-Adaption durchführt.2. Fuel injection system according to claim 1,
characterized,
that the correction device carries out a lambda adaptation when the maximum deviation value Tlmax is less than the limit value GW under corresponding operating conditions. 3. Kraftstoffeinspritzsystem nach Anspruch 1,
dadurch gekennzeichnet,
daß in der Zuleitung 4 ein Absperrventil vorgesehen ist, das oberhalb einem bestimmten Saugrohrdruck die Zuleitung 4 schließt.3. Fuel injection system according to claim 1,
characterized,
that a shut-off valve is provided in the feed line 4, which closes the feed line 4 above a certain intake manifold pressure. 4. Kraftstoffeinspritzsystem nach Anspruch 3,
dadurch gekennzeichnet,
daß das Absperrventil unterhalb einer bestimmten Kühlwassertemperatur schließt.4. Fuel injection system according to claim 3,
characterized,
that the shut-off valve closes below a certain cooling water temperature.
EP19900120421 1990-10-24 1990-10-24 Engine injection system Expired - Lifetime EP0482239B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP19900120421 EP0482239B1 (en) 1990-10-24 1990-10-24 Engine injection system
DE90120421T DE59004362D1 (en) 1990-10-24 1990-10-24 Fuel injection system for an internal combustion engine.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19900120421 EP0482239B1 (en) 1990-10-24 1990-10-24 Engine injection system

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EP0482239A1 true EP0482239A1 (en) 1992-04-29
EP0482239B1 EP0482239B1 (en) 1994-01-19

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0636778A1 (en) * 1993-07-20 1995-02-01 Magneti Marelli France Method and apparatus for correcting the injection time as a function of the purge flow of a canister purge system in a fuel injected engine
EP0691469A1 (en) * 1994-07-05 1996-01-10 Regie Nationale Des Usines Renault S.A. Method of control of an internal combustion engine with canister purge system
DE4430971A1 (en) * 1994-08-31 1996-03-07 Bayerische Motoren Werke Ag Method and device for supplying fuel vapor into an intake manifold of an internal combustion engine in motor vehicles
DE19708937A1 (en) * 1997-03-05 1998-09-17 Mannesmann Vdo Ag Combustion engine and method of its operation
EP2878798A1 (en) * 2013-11-27 2015-06-03 Robert Bosch Gmbh Device and method for determining the loading of an intermediate fuel vapour storage device of a combustion engine

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0191170B1 (en) * 1985-01-26 1989-03-29 Robert Bosch Gmbh Fuel vapour purging device for a fuel tank
WO1990000225A1 (en) * 1988-07-01 1990-01-11 Robert Bosch Gmbh Adaptive process and device for fuel tank ventilation with lambda regulation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0191170B1 (en) * 1985-01-26 1989-03-29 Robert Bosch Gmbh Fuel vapour purging device for a fuel tank
WO1990000225A1 (en) * 1988-07-01 1990-01-11 Robert Bosch Gmbh Adaptive process and device for fuel tank ventilation with lambda regulation

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Title
PATENT ABSTRACTS OF JAPAN, Band 3, Nr. 148 (M-083), 7. Dezember 1979; & JP-A-54 124 117 (FUJI) 26-09-1979 *
PATENT ABSTRACTS OF JAPAN, Band 6, Nr. 126 (M-142), 10. Juli 1982; & JP-A-57 52 663 (TOYOTA) 29-03-1982 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0636778A1 (en) * 1993-07-20 1995-02-01 Magneti Marelli France Method and apparatus for correcting the injection time as a function of the purge flow of a canister purge system in a fuel injected engine
EP0691469A1 (en) * 1994-07-05 1996-01-10 Regie Nationale Des Usines Renault S.A. Method of control of an internal combustion engine with canister purge system
FR2722247A1 (en) * 1994-07-05 1996-01-12 Renault Regie Nationale Usines METHOD FOR CONTROLLING AN INTERNAL COMBUSTION ENGINE WITH RECYCLING OF PURGE GAS FROM THE TANK VENT
DE4430971A1 (en) * 1994-08-31 1996-03-07 Bayerische Motoren Werke Ag Method and device for supplying fuel vapor into an intake manifold of an internal combustion engine in motor vehicles
EP0699832A3 (en) * 1994-08-31 1996-05-22 Bayerische Motoren Werke Ag Method of and device for admitting fuel vapour in a suction tube of an engine in a vehicle
DE19708937A1 (en) * 1997-03-05 1998-09-17 Mannesmann Vdo Ag Combustion engine and method of its operation
EP2878798A1 (en) * 2013-11-27 2015-06-03 Robert Bosch Gmbh Device and method for determining the loading of an intermediate fuel vapour storage device of a combustion engine

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