EP0489864B1 - Process for operating an internal combustion engine - Google Patents

Process for operating an internal combustion engine Download PDF

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Publication number
EP0489864B1
EP0489864B1 EP90914396A EP90914396A EP0489864B1 EP 0489864 B1 EP0489864 B1 EP 0489864B1 EP 90914396 A EP90914396 A EP 90914396A EP 90914396 A EP90914396 A EP 90914396A EP 0489864 B1 EP0489864 B1 EP 0489864B1
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EP
European Patent Office
Prior art keywords
mixture
combustion engine
internal combustion
control
probe
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP90914396A
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German (de)
French (fr)
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EP0489864A1 (en
Inventor
Hellmut Dipl.-Ing. Freudenberg
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Siemens AG
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Siemens AG
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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
    • F02D41/02—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
    • F02D41/1486—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor with correction for particular operating conditions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
    • F02D41/068—Introducing corrections for particular operating conditions for engine starting or warming up for warming-up
    • 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
    • F02D41/1486—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor with correction for particular operating conditions
    • F02D41/1488—Inhibiting the regulation
    • 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
    • F02D41/1454—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 an oxygen content or concentration or the air-fuel ratio
    • F02D41/1456—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 an oxygen content or concentration or the air-fuel ratio with sensor output signal being linear or quasi-linear with the concentration of oxygen

Definitions

  • the invention relates to a method for operating an internal combustion engine according to the preamble of claim 1.
  • a customary ⁇ control regulates the mixture of fuel and air to be supplied to an internal combustion engine to a stoichiometric ratio. During special operating conditions that require a rich mixture, the ⁇ control must therefore be switched off and a controller takes over its task.
  • a mixture control system for an internal combustion engine with a ⁇ control is known, the ⁇ probe providing a linear output signal.
  • a temperature-dependent control of a choke valve takes place before the ⁇ probe is ready for operation. A occurs during the warm-up phase of the machine and after the operating temperature of the ⁇ probe has been reached ⁇ control roughly via the choke valve and fine via a bypass valve.
  • a ⁇ probe with a linear characteristic ensures that a fuel-air mixture can be regulated in a range from lean to rich even in the warm-up phase of the internal combustion engine.
  • the object of the invention is to improve the mixture control during such special operating states of the machine.
  • the solution according to the invention consists in switching on the ⁇ control even during control operation with a limited control range.
  • the control range of the ⁇ regulator is therefore limited so that it regulates only in the rich direction and not in the lean direction.
  • the ⁇ control does not apply to a rich mixture. However, if the control incorrectly sets a lean mixture, the ⁇ control can intervene in the enriching direction and thus reduce the error to an acceptable level.
  • the ⁇ controller with the limited control range is therefore switched on when the internal combustion engine is started, when the probe operating temperature of the ⁇ probe is reached, that is to say immediately when the ⁇ control itself is ready for operation. Only when a minimum cooling water temperature is reached, which indicates the end of warm-up, at which the machine no longer needs a rich mixture, will the control range be released without restriction in the direction of rich and lean.
  • acceleration mode special operating conditions that require a rich mixture are acceleration mode and full load mode.
  • the probe operating temperature of the ⁇ probe has already been reached and therefore the ⁇ control with a limited control range can be switched on during the entire acceleration or full-load operation.
  • the air ratio ⁇ is plotted against the cooling water temperature TKW.
  • TKW cooling water temperature
  • the machine is in the warm-up phase until a minimum cooling water temperature TKWM is reached.
  • a rich mixture is set at the start depending on the level of the cooling water temperature TKW.
  • this initially set mixture is then controlled to the stoichiometric mixture ratio until the minimum cooling water temperature TKWM is reached.
  • Such an ideal mixture flow is shown in FIG. 1 with the solid line.
  • the ⁇ control then regulates a stoichiometric mixture ratio, which in turn is idealized in FIG. 1.
  • Two dashed lines run parallel to the ideal mixture curve during the warm-up phase, which illustrate the fluctuation range of the mixture values set by a real controller.
  • a mixture course according to the lower line means an enrichment going beyond the required level and the upper line an insufficient enrichment.
  • the mixture progression according to the upper line there are even mixture values towards the end of the warm-up phase which are above the stoichiometric ratio in the lean direction. However, this is undesirable, especially during the warm-up phase, since the smooth running of the machine can then no longer be guaranteed.
  • Such a lean mixture is reliably prevented by the method according to the invention during the warm-up phase. Because, in addition to the control system, the ⁇ control is only switched on for the control in the bold direction, all mixture values set by the control system which are above the stoichiometric ratio are adjusted back to the stoichiometric ratio. Mixture values lying in the area of the triangle hatched in FIG. 1 are therefore not possible. As long as the control system sets mixture values below the stoichiometric ratio in the rich direction, the ⁇ control cannot intervene, since the control system is blocked in the lean direction.
  • FIG. 2. 1 denotes a ⁇ controller, 3 a logic device and 4 a controller.
  • the functions of these three devices are carried out by a microcomputer MC with appropriate programming.
  • the microcomputer MC receives the signals for an air ratio ⁇ from a ⁇ probe 2, a cooling water temperature TKW from a temperature sensor 5, a speed n from a speed sensor 6 and an air mass LM from an air mass meter 7.
  • An output of the microcomputer MC is connected to injectors 8 with appropriate control. The amount of fuel injected, and thus the mixture ratio, is determined via the opening time of the individual injection valves controlled by this.
  • the control 4 receives the cooling water temperature TKW, the speed n and the air mass LM as input variables.
  • the control 4 determines the fuel quantity to be injected from a characteristic map via the speed n and the air mass LM, that is to say the load on the machine.
  • Another map contains an additional amount of fuel required for a cold start depending on the cooling water temperature TKW. This enrichment, which is brought about in the event of a cold start, is then carried out in accordance with that in FIG function shown until the end of the warm-up phase.
  • the ⁇ controller 1 receives the air ratio ⁇ as an input variable and uses it to determine fuel injection values that correspond to a stoichiometric mixture ratio.
  • the output signals of the controller 4 and the ⁇ controller 1 are fed to a logic device 3. This selects the one of the two output signals that is passed on to the injection valves 8.
  • the air ratio ⁇ and the cooling water temperature TKW are supplied to the logic device 3.
  • the selection is explained on the basis of the flow chart of FIG. 3.
  • step S1 the logic device 3 checks whether the probe temperature TS of the ⁇ probe 2 is greater than / equal to the probe operating temperature TSB.
  • This probe temperature TS is calculated via the voltage level of the output signal of the ⁇ probe 2 representing the air ratio ⁇ .
  • the probe temperature TS could of course also be obtained from the output signal of a temperature sensor assigned to the ⁇ probe 2.
  • step S1 If the answer in step S1 is no, the ⁇ probe 2 is not yet ready for operation and the logic device 3 calls a program block "control" which represents the function of the control 4.
  • step S2 follows. It is checked whether the cooling water temperature TKW is greater than or equal to the minimum cooling water temperature TKM.
  • the logic device 3 accordingly calls a program block "control and ⁇ regulation"
  • This program block contains the functions of the controller 4 and the ⁇ controller 1, the function of the ⁇ controller 1 being carried out only in the greasing direction.
  • the ⁇ controller is therefore only active if the controller produces mixture values would lie above the stoichiometric ratio in the lean direction In this case, the function corresponding to the ⁇ controller 1 is activated so that the set mixture values do not exceed the stoichiometric ratio.
  • step S2 After the warm-up phase has ended, the answer in step S2 is yes, since the minimum cooling water temperature TKWM has been reached. Then follows a program block " ⁇ control" which performs the usual function of a ⁇ control.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

It is known that, during special operating conditions, e.g. warming-up, acceleration, full-power conditions, the mixture setting is effected by a control system instead of μ-adjustment. This may result in a lean mixture. The invention seeks to avoid this by ensuring that the μ-adjustment remains in operation during the special operating conditions, within a restricted range. It is superimposed on the pilot control, and only takes effect in the direction of enrichment.

Description

Die Erfindung betrifft ein Verfahren zum Betrieb einer Brennkraftmaschine gemäß Oberbegriff von Anspruch 1.The invention relates to a method for operating an internal combustion engine according to the preamble of claim 1.

Eine übliche λ-Regelung regelt das einer Brennkraftmaschine zuzuführende Gemisch aus Kraftstoff und Luft auf ein stöchiometrisches Verhältnis ein. Während Sonderbetriebszuständen, die ein fettes Gemisch erfordern, muß die λ-Regelung daher ausgeschaltet werden und ihre Aufgabe übernimmt eine Steuerung.A customary λ control regulates the mixture of fuel and air to be supplied to an internal combustion engine to a stoichiometric ratio. During special operating conditions that require a rich mixture, the λ control must therefore be switched off and a controller takes over its task.

Dieses Verfahren arbeitet zufriedenstellend, solange die Steuerung während des Sonderbetriebs das geforderte fette Gemisch richtig einstellt. Durch Fehljustierung oder entsprechende Langzeitveränderungen kann es jedoch dazu kommen, daß statt des geforderten fetten ein mageres Gemisch eingestellt wird. Insbesondere gegen Ende eines Sonderbetriebs, wenn das fette Gemisch auf ein stöchiometrisches Gemischverhältnis zurückgefahren wird, um einen kontinuierlichen Ubergang zur nachfolgenden λ-Regelung zu erreichen, führen bereits geringe Fehljustierungen der Steuerung in Richtung mager zu einem unerwünscht mageren Gemisch. Da bei der Steuerung keine Rückkopplung vorhanden ist wird dieser Fehler auch nicht erkannt und äußert sich nur durch ein verschlechtertes Betriebsverhalten der Maschine.This procedure works satisfactorily as long as the controller correctly sets the required rich mixture during the special operation. However, incorrect adjustment or corresponding long-term changes can result in a lean mixture being set instead of the required rich one. In particular, towards the end of a special operation, when the rich mixture is reduced to a stoichiometric mixture ratio in order to achieve a continuous transition to the subsequent λ control, even slight misalignments of the control in the lean direction lead to an undesirably lean mixture. Since there is no feedback in the control, this error is not recognized either and only manifests itself through a deteriorated operating behavior of the machine.

Aus der US-A-4 753 209 ist ein Gemischregelsystem für eine Brennkraftmaschine mit einer λ-Regelung bekannt, wobei die λ-Sonde ein lineares Ausgangssignal liefert. Vor Betriebsbereitschaft der λ-Sonde erfolgt eine temperaturabhängige Steuerung eines Choke-Ventils. Während der Warmlaufphase der Maschine und nach Erreichen der Betriebstemperatur der λ-Sonde erfolgt eine λ-Regelung grob über das Choke-Ventil und fein über ein Bypass-Ventil. Durch eine λ -Sonde mit linearer Charakteristik wird erreicht, daß auch in der Warmlaufphase der Brennkraftmaschine ein Kraftstoff-Luft-Gemisch in einem Bereich von mager bis fett eingeregelt werden kann.From US-A-4 753 209 a mixture control system for an internal combustion engine with a λ control is known, the λ probe providing a linear output signal. Before the λ probe is ready for operation, a temperature-dependent control of a choke valve takes place. A occurs during the warm-up phase of the machine and after the operating temperature of the λ probe has been reached λ control roughly via the choke valve and fine via a bypass valve. A λ probe with a linear characteristic ensures that a fuel-air mixture can be regulated in a range from lean to rich even in the warm-up phase of the internal combustion engine.

Die Aufgabe der Erfindung besteht demgegenüber darin, die Gemischsteuerung während solcher Sonderbetriebszustände der Maschine zu verbessern.In contrast, the object of the invention is to improve the mixture control during such special operating states of the machine.

Die erfindungsgemäße Lösung ist im 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 besteht darin, die λ-Regelung auch während des Steuerbetriebs mit beschränktem Regelbereich einzuschalten. Mit unbeschränktem Regelbereich würde die λ-Regelung das von der Steuerung eingestellte fette Gemisch in Richtung mager auf ein stöchiometrisches Verhältnis mit einer Luftzahl von λ = 1 zurückregeln. Der Regelbereich des λ-Reglers wird daher so beschränkt, daß er nur in Richtung fett regelt und nicht in Richtung mager. Die λ-Regelung greift also bei fettem Gemisch nicht ein. Stellt die Steuerung jedoch fälschlicherweise ein mageres Gemisch ein, so kann die λ-Regelung in anfettender Richtung eingreifen und so den Fehler auf ein erträgliches Maß abmildern.The solution according to the invention consists in switching on the λ control even during control operation with a limited control range. With an unrestricted control range, the λ control would regulate the rich mixture set by the control in the lean direction to a stoichiometric ratio with an air ratio of λ = 1. The control range of the λ regulator is therefore limited so that it regulates only in the rich direction and not in the lean direction. The λ control does not apply to a rich mixture. However, if the control incorrectly sets a lean mixture, the λ control can intervene in the enriching direction and thus reduce the error to an acceptable level.

Der Warmlauf der Brennkraftmaschine ist einer der Sonderbetriebszustände, die ein fettes Gemisch erfordern. Gemäß einer Weiterbildung der Erfindung wird daher nach dem Start der Brennkraftmaschine der λ-Regler mit dem beschränkten Regelbereich bereits bei Erreichen einer Sondenbetriebstemperatur der λ-Sonde eingeschaltet, also sofort wenn die λ-Regelung selbst betriebsbereit ist. Erst beim Erreichen einer Kühlwassermindesttemperatur, die das Ende des Warmlaufs anzeigt, an dem die Maschine kein fettes Gemich mehr braucht, wird der Regelbereich dann unbeschränkt in Richtung fett und mager freigegeben.Warm-up of the internal combustion engine is one of the special operating conditions that require a rich mixture. According to a further development of the invention, the λ controller with the limited control range is therefore switched on when the internal combustion engine is started, when the probe operating temperature of the λ probe is reached, that is to say immediately when the λ control itself is ready for operation. Only when a minimum cooling water temperature is reached, which indicates the end of warm-up, at which the machine no longer needs a rich mixture, will the control range be released without restriction in the direction of rich and lean.

Weitere Sonderbetriebszustande, die ein fettes Gemisch erfordern sind der Beschleunigungsbetrieb und der Vollastbetrieb. Dabei ist die Sondenbetriebstemperatur der λ-Sonde bereits erreicht und daher kann die λ-Regelung mit beschränkten Regelbereich während des gesamten Beschleunigungs- bzw. Vollastbetriebs eingeschaltet sein.Other special operating conditions that require a rich mixture are acceleration mode and full load mode. The probe operating temperature of the λ probe has already been reached and therefore the λ control with a limited control range can be switched on during the entire acceleration or full-load operation.

Die Erfindung wird anhand der Figuren näher erläutert. Dabei zeigen

Figur 1
ein Diagramm zur Erläuterung des erfindungsgemäßen Verfahrens, am Beispiel des Warmlaufs
Figur 2
ein vereinfachtes Blockschaltbild einer Einrichtung zur Durchführung des Verfahrens und
Figur 3
ein Flußdiagramm zur Durchführung des Verfahrens.
The invention is explained in more detail with reference to the figures. Show
Figure 1
a diagram for explaining the inventive method, using the example of warming up
Figure 2
a simplified block diagram of a device for performing the method and
Figure 3
a flow chart for performing the method.

Im Diagramm der Figur 1 ist die Luftzahl λ über der Kühlwassertemperatur TKW aufgetragen. Bei einer Luftzahl von λ = 1 liegt ein stöchiometrisches Verhältnis von Kraftstoff und Luft vor, das eine optimale Verbrennung bedeutet. Luftzahlwerte von λ kleiner als 1 signalisieren ein Gemisch mit erhöhten Kraftstoffwerten gegenüber dem stöchiometrischen Verhältnis und dementsprechend Luftzahlwerte größer als 1 ein mageres Gemisch mit erhöhten Luftwerten.In the diagram in FIG. 1, the air ratio λ is plotted against the cooling water temperature TKW. At an air ratio of λ = 1, there is a stoichiometric ratio of fuel and air, which means optimal combustion. Air ratio values of λ less than 1 signal a mixture with increased fuel values compared to the stoichiometric ratio and accordingly air ratio values greater than 1 indicate a lean mixture with increased air values.

Bis zum Erreichen einer Kühlwassermindesttemperatur TKWM befindet sich die Maschine in der Warmlaufphase. Dabei wird abhängig von der Höhe der Kühlwassertemperatur TKW beim Start ein fettes Gemisch eingestellt. Entsprechend der Erwärmung der Maschine wird dieses anfänglich eingestellte Gemisch dann bis zum Erreichen der Kühlwassermindesttemperatur TKWM auf das stöchiometrische Gemischverhältnis gesteuert. Ein solcher idealer Gemischverlauf ist in der Figur 1 anhand der durchgezogenen Linie dargestellt. Ab Erreichen der Kühlwassermindesttemperatur TKWM regelt dann die λ-Regelung ein stöchiometrisches Gemischverhältnis ein, was in der Figur 1 wiederum idealisiert dargestellt ist.The machine is in the warm-up phase until a minimum cooling water temperature TKWM is reached. A rich mixture is set at the start depending on the level of the cooling water temperature TKW. In accordance with the heating of the machine, this initially set mixture is then controlled to the stoichiometric mixture ratio until the minimum cooling water temperature TKWM is reached. Such an ideal mixture flow is shown in FIG. 1 with the solid line. Once the minimum cooling water temperature TKWM has been reached, the λ control then regulates a stoichiometric mixture ratio, which in turn is idealized in FIG. 1.

Parallel zu dem idealen Gemischverlauf während der Warmlaufphase verlaufen zwei gestrichelte Linien, die die Schwankungsbreite der von einer realen Steuerung eingestellten Gemischwerte veranschaulichen. Ein Gemischverlauf gemäß der unteren Linie bedeutet also eine über das erforderliche Maß hinausgehende Anfettung und die obere Linie eine zu kleine Anfettung. Beim Gemischverlauf gemäß der oberen Linie kommt es dabei gegen Ende der Warmlaufphase sogar zu Gemischwerten, die überhalb dem stöchiometrischen Verhältnis in Richtung mager liegen. Gerade während der Warmlaufphase ist dies jedoch unerwünscht, da dann der einwandfreie Rundlauf der Maschine nicht mehr gewährleistet ist.Two dashed lines run parallel to the ideal mixture curve during the warm-up phase, which illustrate the fluctuation range of the mixture values set by a real controller. A mixture course according to the lower line means an enrichment going beyond the required level and the upper line an insufficient enrichment. In the case of the mixture progression according to the upper line, there are even mixture values towards the end of the warm-up phase which are above the stoichiometric ratio in the lean direction. However, this is undesirable, especially during the warm-up phase, since the smooth running of the machine can then no longer be guaranteed.

Durch das erfindungsgemäße Verfahren wird ein solches mageres Gemisch während der Warmlaufphase sicher verhindert. Dadurch, daß zusätzlich zur Steuerung auch die λ-Regelung nur zur Regelung in Richtung fett eingeschaltet ist, werden alle von der Steuerung eingestellten Gemischwerte die über dem stöchiometrischen Verhältnis liegen, auf das stöchiometrische Verhältnis zurückgeregelt. Gemischwerte die im Bereich des in Figur 1 schraffiert eingezeichneten Dreiecks liegen sind also nicht möglich. Solange die Steuerung Gemischwerte unterhalb des stöchiometrischen Verhältnisses in Richtung fett einstellt kann die λ-Regelung nicht eingreifen, da die Regelung in Richtung mager blockiert ist.Such a lean mixture is reliably prevented by the method according to the invention during the warm-up phase. Because, in addition to the control system, the λ control is only switched on for the control in the bold direction, all mixture values set by the control system which are above the stoichiometric ratio are adjusted back to the stoichiometric ratio. Mixture values lying in the area of the triangle hatched in FIG. 1 are therefore not possible. As long as the control system sets mixture values below the stoichiometric ratio in the rich direction, the λ control cannot intervene, since the control system is blocked in the lean direction.

Eine Einrichtung zum Betrieb einer Brennkraftmaschine zur Durchführung des erfindungsgemäßen Verfahrens ist in Figur 2 gezeigt. Darin ist mit 1 ein λ-Regler, mit 3 eine Logikeinrichtung und mit 4 eine Steuerung bezeichnet. Die Funktionen dieser drei Einrichtungen werden von einem Microcomputer MC mit entsprechender Programmierung ausgeführt.A device for operating an internal combustion engine for carrying out the method according to the invention is shown in FIG. 2. 1 denotes a λ controller, 3 a logic device and 4 a controller. The functions of these three devices are carried out by a microcomputer MC with appropriate programming.

Der Microcomputer MC erhält an entsprechenden Eingängen die Signale für eine Luftzahl λ von einer λ -Sonde 2, eine Kühlwassertemperatur TKW von einem Temperaturgeber 5, eine Drehzahl n von einem Drehzahlgeber 6 und eine Luftmasse LM von einem Luftmassenmesser 7. Ein Ausgang des Microcomputers MC ist mit Einspritzventilen 8 mit entsprechender Ansteuerung verbunden. Über die darüber gesteuerte Öffnungszeit der einzelnen Einspritzventile ist die eingespritzte Kraftstoffmenge festgelegt und damit das Gemischverhältnis.At appropriate inputs, the microcomputer MC receives the signals for an air ratio λ from a λ probe 2, a cooling water temperature TKW from a temperature sensor 5, a speed n from a speed sensor 6 and an air mass LM from an air mass meter 7. An output of the microcomputer MC is connected to injectors 8 with appropriate control. The amount of fuel injected, and thus the mixture ratio, is determined via the opening time of the individual injection valves controlled by this.

Für den Steuerungsbetrieb erhält die Steuerung 4 als Eingangsgrößen die Kühlwassertemperatur TKW, die Drehzahl n sowie die Luftmasse LM. Über die Drehzahl n und die Luftmasse LM, also die Last der Maschine, ermittelt die Steuerung 4 aus einem Kennfeld die einzuspritzende Kraftstoffmenge. Ein weiteres Kennfeld enthält eine für den Kaltstartfall zusätzlich erforderliche Kraftstoffmenge abhängig von der Kühlwassertemperatur TKW. Diese im Kaltstartfall bewirkte Anfettung wird dann gemäß der in Figur 1 gezeigten Funktion bis zum Ende der Warmlaufphase wieder zurückgefahren.For the control operation, the control 4 receives the cooling water temperature TKW, the speed n and the air mass LM as input variables. The control 4 determines the fuel quantity to be injected from a characteristic map via the speed n and the air mass LM, that is to say the load on the machine. Another map contains an additional amount of fuel required for a cold start depending on the cooling water temperature TKW. This enrichment, which is brought about in the event of a cold start, is then carried out in accordance with that in FIG function shown until the end of the warm-up phase.

Für die λ-Regelung erhält der λ-Regler 1 als Eingangsgröße die Luftzahl λ und ermittelt daraus Kraftstoffeinspritzwerte, die einem stöchiometrischen Gemischverhältnis entsprechen.For the λ control, the λ controller 1 receives the air ratio λ as an input variable and uses it to determine fuel injection values that correspond to a stoichiometric mixture ratio.

Die Ausgangssignale der Steuerung 4 und des λ-Reglers 1 werden einer Logikeinrichtung 3 zugeführt. Diese wählt dasjenige der beiden Ausgangssignale aus, das an die Einspritzventile 8 weitergegeben wird.The output signals of the controller 4 and the λ controller 1 are fed to a logic device 3. This selects the one of the two output signals that is passed on to the injection valves 8.

Um diese Auswahl zu treffen sind der Logikeinrichtung 3 die Luftzahl λ und die Kühlwassertemperatur TKW zugeführt. Die Auswahl wird anhand des Flußdiagramms der Figur 3 erläutert.In order to make this selection, the air ratio λ and the cooling water temperature TKW are supplied to the logic device 3. The selection is explained on the basis of the flow chart of FIG. 3.

Im Schritt S1 prüft die Logikeinrichtung 3, ob die Sondentemperatur TS der λ-Sonde 2 größer/gleich der Sondenbetriebstemperatur TSB ist. Die Berechnung dieser Sondentemperatur TS geschieht über das Spannungsniveau des die Luftzahl λ darstellenden Ausgangssignals der λ-Sonde 2. Die Sondentemperatur TS könnte natürlich auch aus dem Ausgangssignal eines der λ-Sonde 2 zugeordneten Temperaturgebers gewonnen werden.In step S1, the logic device 3 checks whether the probe temperature TS of the λ probe 2 is greater than / equal to the probe operating temperature TSB. This probe temperature TS is calculated via the voltage level of the output signal of the λ probe 2 representing the air ratio λ. The probe temperature TS could of course also be obtained from the output signal of a temperature sensor assigned to the λ probe 2.

Ist die Antwort im Schritt S1 nein, so ist die λ-Sonde 2 noch nicht betriebsbereit und die Logikeinrichtung 3 ruft einen Programmblock "Steuerung"auf, der die Funktion der Steuerung 4 darstellt.If the answer in step S1 is no, the λ probe 2 is not yet ready for operation and the logic device 3 calls a program block "control" which represents the function of the control 4.

Ist die Antwort im Schritt S1 dagegen ja, die λ-Sonde 2 also betriebsbereit, so folgt der Schritt S2. Dabei wird geprüft, ob die Kühlwassertemperatur TKW größer oder gleich der Kühlwassermindesttemperatur TKM ist.If, on the other hand, the answer in step S1 is yes, ie the λ probe 2 is ready for operation, step S2 follows. It is checked whether the cooling water temperature TKW is greater than or equal to the minimum cooling water temperature TKM.

Ist dies nicht der Fall, die Antwort also nein, so befindet sich die Maschine in ihrer Warmlaufphase. Die Logikeinrichtung 3 ruft dementsprechend einen Programmblock "Steuerung und λ-Regelung fett" auf. Dieser Programmblock beinhaltet die Funktionen der Steuerung 4 und des λ-Reglers 1, wobei die Funktion des λ-Reglers 1 nur in anfettender Richtung ausgeführt wird. Die λ-Regelung wird also nur aktiv, wenn sich durch die Steuerung Gemischwerte ergeben würden, die überhalb des stöchiometrischen Verhältnisses in Richtung mager liegen. In diesem Fall wird die Funktion entsprechend dem λ-Regler 1 aktiv, so daß die eingestellten Gemischwerte das stöchiometrische Verhältnis nicht überschre iten.If this is not the case, so the answer is no, the machine is in its warm-up phase. The logic device 3 accordingly calls a program block "control and λ regulation This program block contains the functions of the controller 4 and the λ controller 1, the function of the λ controller 1 being carried out only in the greasing direction. The λ controller is therefore only active if the controller produces mixture values would lie above the stoichiometric ratio in the lean direction In this case, the function corresponding to the λ controller 1 is activated so that the set mixture values do not exceed the stoichiometric ratio.

Nach Beendigung der Warmlaufphase ist die Antwort im Schritt S2 ja, da die Kühlwassermindesttemperatur TKWM erreicht ist. Dann folgt ein Programmblock "λ-Regelung", der die übliche Funktion einer λ-Regelung ausführt.After the warm-up phase has ended, the answer in step S2 is yes, since the minimum cooling water temperature TKWM has been reached. Then follows a program block "λ control" which performs the usual function of a λ control.

Claims (4)

  1. Process for operating an internal combustion engine, with a λ probe (2) and a λ adjuster (1) which adjusts the mixture of fuel and air to be fed to the internal combustion engine to a setpoint value as a function of the output signal of the λ probe (2) in the adjusting mode and with a control (4) which, during special operating conditions, sets the fuel/air mixture to a mixture value which lies on the rich side, below the setpoint value which the λ adjuster (1) sets outside the special operating conditions, characterised in that, during the special operating conditions, the λ adjuster (1) acts asymmetrically, adjusting the mixture only in the rich direction.
  2. Process according to Claim 1, characterised in that the special operating condition is the warming up of the internal combustion engine, after the starting of the internal combustion engine and when a probe operating temperature (TSB) is reached, the λ adjuster (1) is switched on with the restricted range of adjustment, and the range of adjustment is enabled without restriction only when a minimum cooling-water temperature (TKWM) is reached.
  3. Process according to Claim 1, characterised in that the special operating condition is the acceleration mode of the internal combustion engine.
  4. Process according to Claim 1, characterised in that the special operating condition is the full-load mode of the internal combustion engine.
EP90914396A 1989-10-05 1990-09-26 Process for operating an internal combustion engine Expired - Lifetime EP0489864B1 (en)

Applications Claiming Priority (2)

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EP89118488 1989-10-05
EP89118488 1989-10-05

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EP0489864A1 EP0489864A1 (en) 1992-06-17
EP0489864B1 true EP0489864B1 (en) 1993-11-18

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EP (1) EP0489864B1 (en)
DE (1) DE59003560D1 (en)
ES (1) ES2046796T3 (en)
WO (1) WO1991005153A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19501458B4 (en) * 1995-01-19 2009-08-27 Robert Bosch Gmbh Method for adapting the warm-up enrichment

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Publication number Priority date Publication date Assignee Title
JP2778383B2 (en) * 1992-10-02 1998-07-23 日産自動車株式会社 Engine air-fuel ratio control device
EP0593800B1 (en) * 1992-10-19 1995-12-27 Siemens Aktiengesellschaft Method to manage an internal combustion engine at full load
DE19955649C2 (en) * 1999-11-19 2002-01-10 Bosch Gmbh Robert Electronic engine control of an internal combustion engine
DE10307004B3 (en) * 2003-02-19 2004-08-05 Siemens Ag Control method for IC engine with lambda regulation e.g. automobile engine, using measured engine temperature for addressing characteristic providing value for engine fuel mixture

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GB1518763A (en) * 1975-03-07 1978-07-26 Nissan Motor Closed loop air fuel ratio control system using exhaust composition sensor
JPS51144828A (en) * 1975-06-09 1976-12-13 Nissan Motor Co Ltd Synthetic exhaust countermeasure system for internal combustion engine
JPS5926781B2 (en) * 1975-11-25 1984-06-30 株式会社デンソー Kuunenhikikanshikikongokiseigiyosouchi
JPS5916090B2 (en) * 1976-06-18 1984-04-13 株式会社デンソー Air-fuel ratio feedback mixture control device
JPS58104336A (en) * 1981-12-16 1983-06-21 Toyota Motor Corp Method of increasing fuel in warming-up and acceleration of electronic control fuel injection system internal combustion engine
JPS6069242A (en) * 1983-09-26 1985-04-19 Nippon Carbureter Co Ltd Air-fuel ratio controlling method for internal-combustion engine
JPS60206953A (en) * 1984-03-30 1985-10-18 Toyota Motor Corp Air-fuel ratio control device in internal-combustion engine
JPS63167061A (en) * 1986-12-27 1988-07-11 Honda Motor Co Ltd Air-fuel ratio control device for internal combustion engine

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19501458B4 (en) * 1995-01-19 2009-08-27 Robert Bosch Gmbh Method for adapting the warm-up enrichment

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WO1991005153A1 (en) 1991-04-18
US5279275A (en) 1994-01-18
DE59003560D1 (en) 1993-12-23
ES2046796T3 (en) 1994-02-01
EP0489864A1 (en) 1992-06-17

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