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EP1608861B1 - Device for controlling an internal combustion engine - Google Patents

Device for controlling an internal combustion engine Download PDF

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Publication number
EP1608861B1
EP1608861B1 EP04820452A EP04820452A EP1608861B1 EP 1608861 B1 EP1608861 B1 EP 1608861B1 EP 04820452 A EP04820452 A EP 04820452A EP 04820452 A EP04820452 A EP 04820452A EP 1608861 B1 EP1608861 B1 EP 1608861B1
Authority
EP
European Patent Office
Prior art keywords
air
cylinder
lam
fuel ratio
estimated value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP04820452A
Other languages
German (de)
French (fr)
Other versions
EP1608861A1 (en
Inventor
Hong Zhang
Gerd RÖSEL
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Continental Automotive GmbH
Original Assignee
VDO Automotive AG
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Filing date
Publication date
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Publication of EP1608861A1 publication Critical patent/EP1608861A1/en
Application granted granted Critical
Publication of EP1608861B1 publication Critical patent/EP1608861B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/008—Controlling each cylinder individually
    • 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
    • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
    • 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
    • F02D41/1458—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 determination means using an estimation
    • 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
    • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
    • F02D2041/1409—Introducing closed-loop corrections characterised by the control or regulation method using at least a proportional, integral or derivative controller
    • 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
    • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
    • F02D2041/1413—Controller structures or design
    • F02D2041/1418—Several control loops, either as alternatives or simultaneous
    • F02D2041/1419—Several control loops, either as alternatives or simultaneous the control loops being cascaded, i.e. being placed in series or nested

Definitions

  • the invention relates to a device for controlling an internal combustion engine having a plurality of cylinders and injectors associated with the cylinders, which meter fuel, with an exhaust gas probe which is arranged in an exhaust tract and whose measurement signal is characteristic for the air / fuel ratio in the respective cylinder.
  • From the DE 199 03 721 C1 is a method for a multi-cylinder internal combustion engine for cylinder-selective control of an air / fuel mixture to be burned, at the lambda values for different cylinders or cylinder groups are sensed and regulated separately.
  • Each cylinder is associated with a single controller, which is designed as a PI or PID controller, whose controlled variable is a cylinder-specific lambda value and whose reference variable is a cylinder-specific desired value of the lambda.
  • the manipulated variable of the respective controller then influences the injection of the fuel in the respective associated cylinder.
  • a method for controlling an internal combustion engine having a controller designed as a PID controller whose controlled variable is an estimate of a cylinder-specific air / fuel ratio determined by an observer and whose command variable is a correspondingly converted mean lambda control factor, rated with a setpoint value. air / fuel ratio.
  • the mean lambda control factor is determined by averaging all cylinder-specific lambda control factors.
  • Each cylinder-specific lambda control factor is the manipulated variable of the respective PID controller assigned to the cylinder.
  • a corrected injection time is determined by multiplying an injection period predetermined for all cylinders of the internal combustion engine by the respective cylinder-specific lambda control factor.
  • the object of the invention is to provide a device for controlling an internal combustion engine, which ensures a precise control of the internal combustion engine.
  • the invention is characterized by an apparatus for controlling an internal combustion engine having a plurality of cylinders and the injection valves associated with the cylinders, which meter fuel, with an exhaust gas probe, which is arranged in an exhaust tract and whose measurement signal is characteristic of the air / fuel ratio in the respective cylinder.
  • a first controller is provided whose control difference is a difference between an actual value and an estimated value of a cylinder-specific deviation of the air / fuel ratio from a predefinable air / fuel ratio.
  • the first controller also has an integral control parameter.
  • the manipulated variable of the first regulator is a first estimate.
  • a second controller is provided whose control difference is the first estimated value and which has a proportional control parameter and whose manipulated variable is a cylinder-individual lambda control factor. Furthermore, a PT1 filter is provided by means of which a second estimated value is determined by PT1 filtering of the cylinder-specific lambda control factor. A unit is provided which determines the estimated value of the cylinder-specific deviation of the air / fuel ratio from the predeterminable air / fuel ratio from the difference between the first and the second estimated value.
  • a block determines a fuel mass to be supplied, which is to be supplied to the respective cylinder of the internal combustion engine, depending on a load size and in which then the supplied fuel mass is corrected depending on the cylinder-individual lambda control factor. Further, in the block, an actuating signal for controlling the injection valve is generated depending on the corrected fuel mass to be supplied.
  • the possible control speed can be increased compared to when the second controller is designed as a further I-controller, which is connected downstream of the first controller.
  • the device according to the invention a high robustness with a very high control accuracy. This is attributable inter alia to the fact that the actual value is taken into account by means of the second estimated value, by means of which the injection valve is activated. The application effort is low in the device according to the invention.
  • the invention is further distinguished by a device for controlling the internal combustion engine, in which the second is supplied to the controller as a control difference, a difference of an actual value and an estimated value of the cylinder-individual deviation of the air / fuel ratio of a predetermined air / fuel ratio.
  • the second controller has another integral control parameter. Its manipulated variable is the cylinder-specific lambda control factor. In this device, too, it is ensured that the second controller can be operated at a high regulating speed and the device has a high degree of robustness with a high control accuracy.
  • the application effort is low in the device according to the invention.
  • a block which adapts the first estimated value by means of a weighting factor before it is fed to the unit. Furthermore, a further block is provided, which adapts the cylinder-specific lambda control factor by means of a further weighting factor before it is fed to the PT1 filter.
  • the cylinder-individual air / fuel ratio can be determined even more precisely when determining the estimated value of the cylinder-specific deviation of the air / fuel ratio, in particular with regard to different lengths of the cylinder outlets to the all cylinders or at least all Cylinders associated with a cylinder bank exhaust probe and with a view to mixing in the respective Cylinders generated exhaust gas packets in the region of the exhaust gas probe.
  • the predefinable air / fuel ratio is an average air / fuel ratio of all cylinder-specific air / fuel ratios.
  • a third controller is provided, the reference variable is a predetermined for all cylinders of the engine air / fuel ratio, the controlled variable is the average air / fuel ratio of all cylinder individual air / fuel ratios and its manipulated variable Lambda control factor is.
  • the predetermined air / fuel ratio can be adjusted easily and precisely in all cylinders.
  • a further advantageous development of the invention provides that the proportional control parameter or the further integral control parameter of the second controller is load-dependent. As a result, the control quality can then be increased simply, since the different mixing of the exhaust gas packages resulting from the individual combustions of the air / fuel mixture in the respective cylinders Z1-Z4 can be easily taken into account.
  • An internal combustion engine ( FIG. 1 ) comprises an intake tract 1, an engine block 2, a cylinder head 3 and an exhaust tract 4.
  • the intake tract preferably comprises a throttle valve 11, a collector 12 and a suction pipe 13 which is guided towards a cylinder Z1 via an intake passage in the engine block.
  • the engine block further comprises a crankshaft 21, which is coupled via a connecting rod 25 with the piston 24 of the cylinder Z1.
  • the cylinder head comprises a valvetrain with a gas inlet valve 30, a gas outlet valve 31 and valve actuators 32, 33.
  • the cylinder head 3 further comprises an injection valve 34 and a spark plug 35.
  • the injection valve may also be disposed in the intake passage.
  • the exhaust tract 4 comprises a catalyst 40, which is preferably designed as a three-way catalyst. From the exhaust tract 4, an exhaust gas recirculation line can be led to the intake tract 1, in particular to the collector 12.
  • a control device 6 is provided, which is associated with sensors which detect different measured variables and in each case determine the measured value of the measured variable.
  • the control device 6 determines dependent on at least one of the measured variables manipulated variables, which are then converted into one or more actuating signals for controlling the actuators by means of corresponding actuators.
  • the sensors are a pedal position sensor 71, which detects the position of an accelerator pedal 7, an air mass meter 14, which detects an air mass flow upstream of the throttle valve 11, a temperature sensor 15 that detects the intake air temperature, a pressure sensor 16 that detects the intake manifold pressure, a crankshaft angle sensor 22 that detects a crankshaft angle, another temperature sensor 23 that detects a coolant temperature, a camshaft angle sensor 36, which detects the camshaft angle and an exhaust gas probe 41 which detects a residual oxygen content of the exhaust gas and whose measurement signal is characteristic of the air / fuel ratio in the cylinder Z1.
  • the exhaust gas probe 41 is preferably designed as a linear lambda probe and thus generates over a wide range of the air / fuel ratio, a proportional to this measurement signal.
  • any subset of said sensors or additional sensors may be present.
  • the actuators are, for example, the throttle valve 11, the gas inlet and gas outlet valves 30, 31, the injection valve 34, the spark plug 35, and the pulse charging valve 18.
  • each bank of cylinders is assigned an exhaust gas probe.
  • the block diagram shows the blocks of the control device 6 which are relevant in connection with the invention.
  • a block B1 corresponds to the internal combustion engine.
  • a block B2 is a cylinder-individually detected air / fuel ratio LAM_I supplied as input.
  • the cylinder-individually detected air / fuel ratio LAM_I is derived from the measurement signal of the exhaust gas probe 41 within a predefinable time or crankshaft angle window, which is assigned to the exhaust gas packet generated in the respective cylinder.
  • a mean air / fuel ratio LAM_MW is determined by averaging the cylinder-individually detected air / fuel ratios LAM_I of all cylinders Z1 to Z4 of the internal combustion engine. Furthermore, in block B2, an actual value D_LAM_I of a cylinder-specific air / fuel ratio deviation is determined from the difference between the average air / fuel ratio LAM_MW and the cylinder / cylinder-specific air / fuel ratio LAM_I.
  • a summing point S1 the difference between the actual value D_LAM_I and an estimated value D_LAM_I_EST of the cylinder-specific air / fuel ratio deviation is determined and then assigned to a block B3 which comprises a first controller and whose input variable is then the control difference of the first controller.
  • the first controller is designed as an integral controller, ie it has an integral control parameter.
  • the manipulated variable of the first regulator is a first estimated value EST1.
  • the first estimated value EST1 is preferably multiplied in a block B4 by a weighting factor that takes into account that the control difference at the input of the first controller is also influenced by exhaust packets of other cylinders Z1 to Z4 due to the different lengths of the outlets of the cylinders Z1 to Z4 towards the Exhaust probe 41 and a mixing of the exhaust gas packets of the individual cylinders Z1 to Z4 in the area the exhaust gas probe 41. Subsequently, the thus corrected first estimated value EST1 is fed to a summing point S2. Alternatively, however, the first estimate EST1 may also be fed directly from the block B3 to the summing point S2.
  • a block B5 comprises a second controller whose control difference is the first estimated value EST1 and which is designed as a P controller, ie has a proportional control parameter.
  • the manipulated variable of the second controller is a cylinder-specific lambda control factor LAM_FAC_I.
  • This cylinder-specific lambda control factor LAM_FAC_I is preferably corrected via a block B6, which corresponds to the block B4, by means of a further weighting factor, and then fed to a block B7 which comprises a PT1 filter which filters the cylinder-specific lambda control factor LAM_FAC_I and thus at its output a second Estimate EST2 provides.
  • the estimated value D_LAM_I_EST of the cylinder-specific air / fuel ratio deviation is determined from the difference of the first and second estimated values EST1, EST2.
  • a third controller is provided whose command variable is a predetermined for all cylinders of the internal combustion engine air / fuel ratio and the controlled variable is the average air / fuel ratio LAM_MW.
  • the manipulated variable of the third controller is a lambda control factor LAM_FAC_ALL. The third controller thus has the task that viewed over all cylinders Z1 to Z4 of the internal combustion engine, the predetermined air / fuel ratio is adjusted.
  • a fuel mass MFF to be metered is determined as a function of an air mass flow MAF in the respective cylinders Z1 to Z4 and optionally the rotational speed N and a target value LAM_SP of the air / fuel ratio for all cylinders Z1-Z4.
  • a corrected fuel mass MFF_COR to be metered is determined by multiplying the fuel mass MFF to be metered, the lambda control factor LAM_FAC_ALL and the cylinder-specific lambda control factor LAM_FAC_I.
  • an actuating signal is then generated with which the respective injection valve 34 is activated.
  • controller structure shown are provided for each additional cylinder Z1 to Z4 corresponding control structures B_Z2 to B_Z4 for the respective further cylinder Z2 to Z4.
  • the second estimated value EST2 compensates the control path dynamics, that is to say the dynamics of the internal combustion engine in such a way that the control interventions of the first and second controllers are included in the determination of the estimated value D_LAM_I_EST of the cylinder-specific air / fuel ratio deviation.
  • the second controller whose controlled variable is the first estimated value EST1
  • the second controller has no further I-component
  • an increase in the possible control speed and an increase in the robustness of the control structure is achieved in comparison to the case in which the second controller additionally has an I-component. Share has.
  • the weighting factor of the block B6 may also be provided with a negative sign. This has the consequence that the second estimated value EST2 is added in the summing point S2.
  • the weighting factors of the blocks B4 and / or B6 are also dependent on the load size, which is preferably the air mass flow MAF in the respective cylinder Z1-Z4 and / or the rotational speed N is.
  • control parameter of the second regulator that is to say the proportional control parameter here
  • the control parameter of the second regulator can also be dependent on the load variable, which is preferably the air mass flow MAF in the respective cylinder Z1-Z4 and / or the rotational speed N.
  • the control quality can then be increased simply, since the different mixing of the exhaust gas packages resulting from the individual combustions of the air / fuel mixture in the respective cylinders Z1-Z4 is taken into account.
  • the second controller in a block B5 ' unlike the second controller, has the FIG. 2 as a control difference, the difference between the actual value D_LAM_I and the estimated value LAM_I_EST of the cylinder-specific air / fuel ratio deviation.
  • the second controller of block B5 ' also has another integral control parameter, which is preferably selected to be the product of the integral control parameter of the first controller of the block B3 and the proportional control parameter of the second controller of the block B5 in FIG FIG. 2 equivalent.
  • the manipulated variable of the second controller is likewise the cylinder-specific lambda control factor LAM_FAC_I.
  • Both the cylinder-specific lambda control factor LAM_FAC_I and the lambda control factor LAM_FAC_ALL can also be corresponding additive correction values for the fuel mass MFF to be metered.

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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

The invention relates to a device for controlling an internal combustion engine, comprising a first regulator, whose regulating difference is the difference of an actual value (D_LAM_I) and an estimated value (D_LAM_I_EST) of individual cylinder deviation of the air/fuel ratio from a preset air/fuel ratio. The first regulator also has an integral regulating parameter, its manipulated variable being a first estimated value (EST1). A second regulator is also provided, the regulating difference of which is the first estimated value (EST1). Said regulator has a proportional regulating parameter whose manipulated variable is an individual cylinder lambda regulating factor (LAM_FAC_I). A PT1 filter is additionally provided, by means of which a second estimated value (EST2) is determined through PT1 filtering of the individual cylinder lambda regulating factor (LAM_FAC_I). A unit is also provided, said unit determining the estimated value (D_LAM_I_EST) of the individual cylinder deviation of the air/fuel ratio from the preset air/fuel ratio based on the difference between the first and the second estimated values (EST1, EST2). Depending on the individual cylinder lambda regulating factor (LAM_FAC_I), a fuel mass that is to be proportioned (MFF) is corrected and the thus corrected fuel mass to be proportioned (MFF_COR) is considered in order to determine a regulating signal for the corresponding injection valve.

Description

Die Erfindung betrifft eine Vorrichtung zum Steuern einer Brennkraftmaschine mit mehreren Zylindern und den Zylindern zugeordneten Einspritzventilen, die Kraftstoff zumessen, mit einer Abgassonde, die in einem Abgastrakt angeordnet ist und deren Messsignal charakteristisch ist für das Luft/Kraftstoff-Verhältnis in dem jeweiligen Zylinder.The invention relates to a device for controlling an internal combustion engine having a plurality of cylinders and injectors associated with the cylinders, which meter fuel, with an exhaust gas probe which is arranged in an exhaust tract and whose measurement signal is characteristic for the air / fuel ratio in the respective cylinder.

Immer strengere gesetzliche Vorschriften bezüglich zulässiger Schadstoffemissionen von Kraftfahrzeugen, in denen Brennkraftmaschinen angeordnet sind, machen es erforderlich, die Schadstoffemissionen beim Betrieb der Brennkraftmaschine so gering wie möglich zu halten. Dies kann zum einen erfolgen, in dem die Schadstoffemissionen, die während der Verbrennung des Luft/Kraftstoff-Gemisches in dem jeweiligen Zylinder der Brennkraftmaschine entstehen, verringert werden. Zum andern sind in Brennkraftmaschine Abgasnachbehandlungssysteme im Einsatz, die die Schadstoffemissionen, die während des Verbrennungsprozesses des Luft/Kraftstoff-Gemisches in den jeweiligen Zylindern erzeugt werden, in unschädliche Stoffe umwandeln. Zu diesem Zweck werden Katalysatoren eingesetzt, die Kohlenmonoxid, Kohlenwasserstoffe und Stickoxide in unschädliche Stoffe umwandeln. Sowohl das gezielte Beeinflussen des Erzeugens der Schadstoffemissionen während der Verbrennung als auch das Umwandeln der Schadstoffkomponenten mit einem hohen Wirkungsgrad durch einen Abgaskatalysator setzen ein sehr präzise eingestelltes Luft/Kraftstoff-Verhältnis in dem jeweiligen Zylinder voraus.Ever stricter legal regulations regarding permissible pollutant emissions from motor vehicles, in which internal combustion engines are arranged, make it necessary to keep the pollutant emissions during operation of the internal combustion engine as low as possible. This can be done firstly, in which the pollutant emissions that arise during the combustion of the air / fuel mixture in the respective cylinder of the internal combustion engine can be reduced. On the other hand, exhaust gas aftertreatment systems are in use in the internal combustion engine, which convert the pollutant emissions which are generated during the combustion process of the air / fuel mixture in the respective cylinders, into harmless substances. For this purpose, catalysts are used, which convert carbon monoxide, hydrocarbons and nitrogen oxides into harmless substances. Both the targeted influencing of the generation of the pollutant emissions during combustion and the conversion of the pollutant components with a high efficiency by an exhaust gas catalyst require a very precisely adjusted air / fuel ratio in the respective cylinder.

Aus der DE 199 03 721 C1 ist ein Verfahren für eine mehrzylindrige Brennkraftmaschine zur zylinderselektiven Regelung eines zu verbrennenden Luft/Kraftstoff-Gemisches bekannt, bei dem die Lambdawerte für verschiedene Zylinder oder Zylindergruppen getrennt sensiert und geregelt werden. Jedem Zylinder ist ein einzelner Regler zugeordnet, der als PI- oder PID-Regler ausgebildet ist, dessen Regelgröße ein zylinderindividueller Lambdawert ist und dessen Führungsgröße ein zylinderindividueller Sollwert des Lambdas ist. Die Stellgröße des jeweiligen Reglers beeinflusst dann die Einspritzung des Kraftstoffs in dem jeweils zugeordneten Zylinder.From the DE 199 03 721 C1 is a method for a multi-cylinder internal combustion engine for cylinder-selective control of an air / fuel mixture to be burned, at the lambda values for different cylinders or cylinder groups are sensed and regulated separately. Each cylinder is associated with a single controller, which is designed as a PI or PID controller, whose controlled variable is a cylinder-specific lambda value and whose reference variable is a cylinder-specific desired value of the lambda. The manipulated variable of the respective controller then influences the injection of the fuel in the respective associated cylinder.

Aus der EP 0 802 316 B1 ist ebenfalls ein Verfahren zum Steuern einer Brennkraftmaschine bekannt, mit einem als PID-Regler ausgebildeten Regler, dessen Regelgröße ein mittels eines Beobachters ermittelter Schätzwert eines zylinderindividuellen Luft/Kraftstoff-Verhältnisses ist und dessen Führungsgröße ein entsprechend umgewandelter mittlerer Lambdaregelfaktor ist, bewertet mit einem Soll-Luft/Kraftstoff-Verhältnis. Der mittlere Lambdaregelfaktor wird durch Mittelung aller zylinderindividuellen Lambdaregelfaktoren ermittelt. Jeder zylinderindividuelle Lambdaregelfaktor ist die Stellgröße des jeweiligen dem Zylinder zugeordneten PID-Reglers. Eine korrigierte Einspritzzeit wird durch Multiplizieren einer für alle Zylinder der Brennkraftmaschine vorgegebenen Einspritzzeitdauer mit dem jeweiligen zylinderindividuellen Lambdaregelfaktor ermittelt.From the EP 0 802 316 B1 A method for controlling an internal combustion engine is also known, having a controller designed as a PID controller whose controlled variable is an estimate of a cylinder-specific air / fuel ratio determined by an observer and whose command variable is a correspondingly converted mean lambda control factor, rated with a setpoint value. air / fuel ratio. The mean lambda control factor is determined by averaging all cylinder-specific lambda control factors. Each cylinder-specific lambda control factor is the manipulated variable of the respective PID controller assigned to the cylinder. A corrected injection time is determined by multiplying an injection period predetermined for all cylinders of the internal combustion engine by the respective cylinder-specific lambda control factor.

Die Aufgabe der Erfindung ist es eine Vorrichtung zum Steuern einer Brennkraftmaschine zu schaffen, die ein präzises Steuern der Brennkraftmaschine gewährleistet.The object of the invention is to provide a device for controlling an internal combustion engine, which ensures a precise control of the internal combustion engine.

Die Aufgabe wird gelöst durch die Merkmale der unabhängigen Patentansprüche. Vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen gekennzeichnet.The object is solved by the features of the independent claims. Advantageous embodiments of the invention are characterized in the subclaims.

Die Erfindung zeichnet sich aus durch eine Vorrichtung zum Steuern einer Brennkraftmaschine mit mehreren Zylindern und den Zylindern zugeordneten Einspritzventilen, die Kraftstoff zumessen, mit einer Abgassonde, die in einem Abgastrakt angeordnet ist und deren Messsignal charakteristisch ist für das Luft/Kraftstoff-Verhältnis in dem jeweiligen Zylinder. Ein erster Regler ist vorgesehen, dessen Regeldifferenz eine Differenz eines Istwertes und eines Schätzwertes einer zylinderindividuellen Abweichung des Luft/Kraftstoff-Verhältnisses ist von einem vorgebbaren Luft/Kraftstoff-Verhältnis. Der erste Regler hat ferner einen Integral-Regelparameter. Die Stellgröße des ersten Reglers ist ein erster Schätzwert. Ferner ist ein zweiter Regler vorgesehen, dessen Regeldifferenz der erste Schätzwert ist und der einen Proportional-Regelparameter hat und dessen Stellgröße ein zylinderindividueller Lambdaregelfaktor ist. Ferner ist ein PT1-Filter vorgesehen, mittels dessen ein zweiter Schätzwert durch PT1-Filterung des zylinderindividuellen Lambdaregelfaktors ermittelt wird. Eine Einheit ist vorgesehen, die den Schätzwert der zylinderindividuellen Abweichung des Luft/Kraftstoff-Verhältnisses von dem vorgebbaren Luft/Kraftstoff-Verhältnis aus der Differenz des ersten und des zweiten Schätzwerts ermittelt.The invention is characterized by an apparatus for controlling an internal combustion engine having a plurality of cylinders and the injection valves associated with the cylinders, which meter fuel, with an exhaust gas probe, which is arranged in an exhaust tract and whose measurement signal is characteristic of the air / fuel ratio in the respective cylinder. A first controller is provided whose control difference is a difference between an actual value and an estimated value of a cylinder-specific deviation of the air / fuel ratio from a predefinable air / fuel ratio. The first controller also has an integral control parameter. The manipulated variable of the first regulator is a first estimate. Furthermore, a second controller is provided whose control difference is the first estimated value and which has a proportional control parameter and whose manipulated variable is a cylinder-individual lambda control factor. Furthermore, a PT1 filter is provided by means of which a second estimated value is determined by PT1 filtering of the cylinder-specific lambda control factor. A unit is provided which determines the estimated value of the cylinder-specific deviation of the air / fuel ratio from the predeterminable air / fuel ratio from the difference between the first and the second estimated value.

Ein Block ist vorgesehen, der eine zuzuführende Kraftstoffmasse ermittelt, die dem jeweiligen Zylinder der Brennkraftmaschine zugeführt werden soll, abhängig von einer Lastgröße und in dem dann die zuzuführende Kraftstoffmasse korrigiert wird abhängig von dem zylinderindividuellen Lambdaregelfaktor. Ferner wird in dem Block ein Stellsignal zum Steuern des Einspritzventils erzeugt abhängig von der korrigierten zuzuführenden Kraftstoffmasse.A block is provided which determines a fuel mass to be supplied, which is to be supplied to the respective cylinder of the internal combustion engine, depending on a load size and in which then the supplied fuel mass is corrected depending on the cylinder-individual lambda control factor. Further, in the block, an actuating signal for controlling the injection valve is generated depending on the corrected fuel mass to be supplied.

Durch den zweiten Regler mit einem P-Anteil kann die mögliche Regelgeschwindigkeit erhöht werden im Vergleich dazu, wenn der zweite Regler als weiterer I-Regler ausgebildet ist, der dem ersten Regler nachgeschaltet ist. Darüber hinaus weist die erfindungsgemäße Vorrichtung eine hohe Robustheit bei einer sehr hohen Regelgenauigkeit auf. Dies ist unter anderem darauf zurückzuführen, dass mittels des zweiten Schätzwertes die tatsächliche Stellgröße berücksichtigt wird, mittels der das Einspritzventil angesteuert wird. Der Applikationsaufwand ist bei der erfindungsgemäßen Vorrichtung gering.By the second controller with a P-component, the possible control speed can be increased compared to when the second controller is designed as a further I-controller, which is connected downstream of the first controller. In addition, points the device according to the invention a high robustness with a very high control accuracy. This is attributable inter alia to the fact that the actual value is taken into account by means of the second estimated value, by means of which the injection valve is activated. The application effort is low in the device according to the invention.

Die Erfindung zeichnet sich ferner durch eine Vorrichtung zum Steuern der Brennkraftmaschine aus, bei der der zweite dem Regler als Regeldifferenz eine Differenz eines Istwertes und eines Schätzwertes der zylinderindividuellen Abweichung des Luft/Kraftstoff-Verhältnisses von einem vorgebbaren Luft/Kraftstoff-Verhältnis zugeführt ist. Der zweite Regler hat einen weiteren Integral-Regelparameter. Seine Stellgröße ist der zylinderindividuelle Lambdaregelfaktor. Auch bei dieser Vorrichtung ist gewährleistet, dass der zweite Regler mit einer hohen Regelgeschwindigkeit betrieben werden kann und die Vorrichtung eine hohe Robustheit bei einer hohen Regelgenauigkeit hat. Der Applikationsaufwand ist bei der erfindungsgemäßen Vorrichtung gering.The invention is further distinguished by a device for controlling the internal combustion engine, in which the second is supplied to the controller as a control difference, a difference of an actual value and an estimated value of the cylinder-individual deviation of the air / fuel ratio of a predetermined air / fuel ratio. The second controller has another integral control parameter. Its manipulated variable is the cylinder-specific lambda control factor. In this device, too, it is ensured that the second controller can be operated at a high regulating speed and the device has a high degree of robustness with a high control accuracy. The application effort is low in the device according to the invention.

In einer vorteilhaften Weiterbildung der Erfindung ist ein Block vorgesehen, der den ersten Schätzwert mittels eines Wichtungsfaktors anpasst, bevor er der Einheit zugeleitet wird. Ferner ist ein weiterer Block vorgesehen, der den zylinderindividuellen Lambdaregelfaktor mittels eines weiteren Wichtungsfaktors anpasst bevor er dem PT1-Filter zugeleitet wird. Auf diese Weise kann das zylinderindividuelle Luft/Kraftstoff-Verhältnis noch präziser bei der Ermittlung des Schätzwertes der zylinderindividuellen Abweichung des Luft/Kraftstoff-Verhältnisses ermittelt werden und zwar insbesondere im Hinblick auf unterschiedliche Längen der Auslässe der Zylinder hin zu der allen Zylindern zugeordneten oder zumindest allen Zylindern einer Zylinderbank zugeordneten Abgassonde und im Hinblick auf eine Vermischung der in den jeweiligen Zylindern erzeugten Abgaspakete im Bereich der Abgassonde.In an advantageous development of the invention, a block is provided which adapts the first estimated value by means of a weighting factor before it is fed to the unit. Furthermore, a further block is provided, which adapts the cylinder-specific lambda control factor by means of a further weighting factor before it is fed to the PT1 filter. In this way, the cylinder-individual air / fuel ratio can be determined even more precisely when determining the estimated value of the cylinder-specific deviation of the air / fuel ratio, in particular with regard to different lengths of the cylinder outlets to the all cylinders or at least all Cylinders associated with a cylinder bank exhaust probe and with a view to mixing in the respective Cylinders generated exhaust gas packets in the region of the exhaust gas probe.

In einer weiteren vorteilhaften Weiterbildung der Erfindung ist das vorgebbare Luft/Kraftstoff-Verhältnis ein mittleres Luft/Kraftstoff-Verhältnis aller zylinderindividuellen Luft/Kraftstoff-Verhältnisse. So kann durch die Vorrichtung sehr präzise ein Gleichstellen der Luft/Kraftstoff-Verhältnisse in allen Zylindern der Brennkraftmaschine gewährleistet werden.In a further advantageous development of the invention, the predefinable air / fuel ratio is an average air / fuel ratio of all cylinder-specific air / fuel ratios. Thus, a very equal equalization of the air / fuel ratios in all cylinders of the internal combustion engine can be ensured by the device.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung ist ein dritter Regler vorgesehen, dessen Führungsgröße ein für alle Zylinder der Brennkraftmaschine vorgegebenes Luft/Kraftstoff-Verhältnis ist, dessen Regelgröße das mittlere Luft/Kraftstoff-Verhältnis aller zylinderindividuellen Luft/Kraftstoff-Verhältnisse ist und dessen Stellgröße ein Lambdaregelfaktor ist. So kann auch einfach und präzise in allen Zylindern das vorgegebene Luft/Kraftstoff-Verhältnis eingestellt werden.In a further advantageous embodiment of the invention, a third controller is provided, the reference variable is a predetermined for all cylinders of the engine air / fuel ratio, the controlled variable is the average air / fuel ratio of all cylinder individual air / fuel ratios and its manipulated variable Lambda control factor is. Thus, the predetermined air / fuel ratio can be adjusted easily and precisely in all cylinders.

Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass der Proportional-Regelparameter bzw. der weitere Integral-Regelparameter des zweiten Reglers lastabhängig vorgegeben ist. Dadurch kann dann die Regelgüte einfach erhöht werden, da die unterschiedliche Vermischung der Abgaspakete die aus den einzelnen Verbrennungen des Luft/Kraftstoff-Gemisches in den jeweiligen Zylindern Z1-Z4 resultieren, einfach berücksichtigt werden können.A further advantageous development of the invention provides that the proportional control parameter or the further integral control parameter of the second controller is load-dependent. As a result, the control quality can then be increased simply, since the different mixing of the exhaust gas packages resulting from the individual combustions of the air / fuel mixture in the respective cylinders Z1-Z4 can be easily taken into account.

Ausführungsbeispiele der Erfindung sind im folgenden anhand der schematischen Zeichnungen erläutert. Es zeigen:

Figur 1
eine Brennkraftmaschine mit einer Steuereinrichtung,
Figur 2
ein Blockschaltbild der Steuereinrichtung,
Figur 3
ein weiteres Blockschaltbild der Steuereinrichtung.
Embodiments of the invention are explained below with reference to the schematic drawings. Show it:
FIG. 1
an internal combustion engine with a control device,
FIG. 2
a block diagram of the control device,
FIG. 3
another block diagram of the control device.

Elemente gleicher Konstruktion und Funktion sind figurenübergreifend mit den gleichen Bezugszeichen gekennzeichnet.Elements of the same construction and function are identified across the figures with the same reference numerals.

Eine Brennkraftmaschine (Figur 1) umfasst einen Ansaugtrakt 1, einen Motorblock 2, einen Zylinderkopf 3 und einen Abgastrakt 4. Der Ansaugtrakt umfasst vorzugsweise eine Drosselklappe 11, ferner einen Sammler 12 und ein Saugrohr 13, das hin zu einem Zylinder Z1 über einen Einlasskanal in den Motorblock geführt ist. Der Motorblock umfasst ferner eine Kurbelwelle 21, welche über eine Pleuelstange 25 mit dem Kolben 24 des Zylinders Z1 gekoppelt ist.An internal combustion engine ( FIG. 1 ) comprises an intake tract 1, an engine block 2, a cylinder head 3 and an exhaust tract 4. The intake tract preferably comprises a throttle valve 11, a collector 12 and a suction pipe 13 which is guided towards a cylinder Z1 via an intake passage in the engine block. The engine block further comprises a crankshaft 21, which is coupled via a connecting rod 25 with the piston 24 of the cylinder Z1.

Der Zylinderkopf umfasst einen Ventiltrieb mit einem Gaseinlassventil 30, einem Gasauslassventil 31 und Ventilantrieben 32, 33. Der Zylinderkopf 3 umfasst ferner ein Einspritzventil 34 und eine Zündkerze 35. Alternativ kann das Einspritzventil auch in dem Ansaugkanal angeordnet sein.The cylinder head comprises a valvetrain with a gas inlet valve 30, a gas outlet valve 31 and valve actuators 32, 33. The cylinder head 3 further comprises an injection valve 34 and a spark plug 35. Alternatively, the injection valve may also be disposed in the intake passage.

Der Abgastrakt 4 umfasst einen Katalysator 40, der bevorzugt als Dreiwegekatalysator ausgebildet ist. Von dem Abgastrakt 4 kann eine Abgasrückführleitung hin zum Ansaugtrakt 1, insbesondere hin zum Sammler 12 geführt sein.The exhaust tract 4 comprises a catalyst 40, which is preferably designed as a three-way catalyst. From the exhaust tract 4, an exhaust gas recirculation line can be led to the intake tract 1, in particular to the collector 12.

Ferner ist eine Steuereinrichtung 6 vorgesehen, der Sensoren zugeordnet sind, die verschiedene Messgrößen erfassen und jeweils den Messwert der Messgröße ermitteln. Die Steuereinrichtung 6 ermittelt abhängig von mindestens einer der Messgrößen Stellgrößen, die dann in ein oder mehrere Stellsignale zum Steuern der Stellglieder mittels entsprechender Stellantriebe umgesetzt werden.Furthermore, a control device 6 is provided, which is associated with sensors which detect different measured variables and in each case determine the measured value of the measured variable. The control device 6 determines dependent on at least one of the measured variables manipulated variables, which are then converted into one or more actuating signals for controlling the actuators by means of corresponding actuators.

Die Sensoren sind ein Pedalstellungsgeber 71, welcher die Stellung eines Fahrpedals 7 erfasst, ein Luftmassenmesser 14, welcher einen Luftmassenstrom stromaufwärts der Drosselklappe 11 erfasst, ein Temperatursensor 15, welcher die Ansauglufttemperatur erfasst, ein Drucksensor 16, welcher den Saugrohrdruck erfasst, ein Kurbelwellenwinkelsensor 22, welcher einen Kurbelwellenwinkel erfasst, ein weiterer Temperatursensor 23, welcher eine Kühlmitteltemperatur erfasst, ein Nockenwellenwinkelsensor 36, welcher den Nockenwellenwinkel erfasst und eine Abgassonde 41 welche einen Restsauerstoffgehalt des Abgases erfasst und deren Messsignal charakteristisch ist für das Luft/Kraftstoff-Verhältnis in dem Zylinder Z1. Die Abgassonde 41 ist bevorzugt als lineare Lambdasonde ausgebildet und erzeugt so über einen weiten Bereich des Luft/Kraftstoff-Verhältnisses ein zu diesem proportionales Messsignal.The sensors are a pedal position sensor 71, which detects the position of an accelerator pedal 7, an air mass meter 14, which detects an air mass flow upstream of the throttle valve 11, a temperature sensor 15 that detects the intake air temperature, a pressure sensor 16 that detects the intake manifold pressure, a crankshaft angle sensor 22 that detects a crankshaft angle, another temperature sensor 23 that detects a coolant temperature, a camshaft angle sensor 36, which detects the camshaft angle and an exhaust gas probe 41 which detects a residual oxygen content of the exhaust gas and whose measurement signal is characteristic of the air / fuel ratio in the cylinder Z1. The exhaust gas probe 41 is preferably designed as a linear lambda probe and thus generates over a wide range of the air / fuel ratio, a proportional to this measurement signal.

Je nach Ausführungsform der Erfindung kann eine beliebige Untermenge der genannten Sensoren oder auch zusätzliche Sensoren vorhanden sein.Depending on the embodiment of the invention, any subset of said sensors or additional sensors may be present.

Die Stellglieder sind beispielsweise die Drosselklappe 11, die Gaseinlass- und Gasauslassventile 30, 31, das Einspritzventil 34, die Zündkerze 35 und das Impulsladeventil 18.The actuators are, for example, the throttle valve 11, the gas inlet and gas outlet valves 30, 31, the injection valve 34, the spark plug 35, and the pulse charging valve 18.

Neben dem Zylinder Z1 sind auch noch weitere Zylinder Z2-Z4 vorgesehen, denen dann auch entsprechende Stellglieder zugeordnet sind. Bevorzugt ist jeder Bank an Zylindern eine Abgassonde zugeordnet.In addition to the cylinder Z1 also more cylinders Z2-Z4 are provided, which then also corresponding actuators are assigned. Preferably, each bank of cylinders is assigned an exhaust gas probe.

Ein Blockschaltbild der Steuereinrichtung 6, die auch als Vorrichtung zum Steuern der Brennkraftmaschine bezeichnet werden kann, ist anhand der Figur 2 dargestellt. In dem Blockschaltbild sind die im Zusammenhang mit der Erfindung relevanten Blöcke der Steuereinrichtung 6 dargestellt. Ein Block B1 entspricht der Brennkraftmaschine.A block diagram of the control device 6, which can also be referred to as a device for controlling the internal combustion engine, is based on the FIG. 2 shown. The block diagram shows the blocks of the control device 6 which are relevant in connection with the invention. A block B1 corresponds to the internal combustion engine.

Einem Block B2 wird ein zylinderindividuell erfasstes Luft/Kraftstoff-Verhältnis LAM_I als Eingangsgröße zugeleitet. Das zylinderindividuell erfasste Luft/Kraftstoff-Verhältnis LAM_I wird aus dem Messsignal der Abgassonde 41 innerhalb eines vorgebbaren Zeit- beziehungsweise Kurbelwellenwinkelfensters abgeleitet, das dem in dem jeweiligen Zylinder erzeugten Abgaspaket zugeordnet wird.A block B2 is a cylinder-individually detected air / fuel ratio LAM_I supplied as input. The cylinder-individually detected air / fuel ratio LAM_I is derived from the measurement signal of the exhaust gas probe 41 within a predefinable time or crankshaft angle window, which is assigned to the exhaust gas packet generated in the respective cylinder.

In dem Block B2 wird ein mittleres Luft/Kraftstoff-Verhältnis LAM_MW durch Mittelung der zylinderindividuell erfassten Luft/Kraftstoff-Verhältnisse LAM_I aller Zylinder Z1 bis Z4 der Brennkraftmaschine ermittelt. Ferner wird in dem Block B2 ein Istwert D_LAM_I einer zylinderindividuellen Luft/Kraftstoff-Verhältnis Abweichung aus der Differenz des mittleren Luft/Kraftstoff-Verhältnisses LAM_MW und des zylinderindividuell erfassten Luft/Kraftstoff-Verhältnisses LAM_I ermittelt.In block B2, a mean air / fuel ratio LAM_MW is determined by averaging the cylinder-individually detected air / fuel ratios LAM_I of all cylinders Z1 to Z4 of the internal combustion engine. Furthermore, in block B2, an actual value D_LAM_I of a cylinder-specific air / fuel ratio deviation is determined from the difference between the average air / fuel ratio LAM_MW and the cylinder / cylinder-specific air / fuel ratio LAM_I.

In einer Summierstelle S1 wird die Differenz des Istwertes D_LAM_I und eines Schätzwertes D_LAM_I_EST der zylinderindividuellen Luft/Kraftstoff-Verhältnis Abweichung ermittelt und dann einem Block B3 zugeordnet, der einen ersten Regler umfasst und dessen Eingangsgröße dann die Regeldifferenz des ersten Reglers ist. Der erste Regler ist als Integral-Regler ausgebildet, das heißt er hat einen Integral-Regelparameter. Die Stellgröße des ersten Reglers ist ein erster Schätzwert EST1.In a summing point S1, the difference between the actual value D_LAM_I and an estimated value D_LAM_I_EST of the cylinder-specific air / fuel ratio deviation is determined and then assigned to a block B3 which comprises a first controller and whose input variable is then the control difference of the first controller. The first controller is designed as an integral controller, ie it has an integral control parameter. The manipulated variable of the first regulator is a first estimated value EST1.

Der erste Schätzwert EST1 wird bevorzugt in einem Block B4 mit einem Wichtungsfaktor multipliziert, der berücksichtigt, dass die Regeldifferenz am Eingang des ersten Reglers auch beeinflusst ist durch Abgaspakete anderer Zylinder Z1 bis Z4 aufgrund der unterschiedlichen Länge der Auslässe der Zylinder Z1 bis Z4 hin zu der Abgassonde 41 und einer Vermischung der Abgaspakete der einzelnen Zylinder Z1 bis Z4 im Bereich der Abgassonde 41. Anschließend wird der so korrigierte erste Schätzwert EST1 einer Summierstelle S2 zugeführt. Alternativ kann der erste Schätzwert EST1 jedoch auch direkt von dem Block B3 der Summierstelle S2 zugeführt sein.The first estimated value EST1 is preferably multiplied in a block B4 by a weighting factor that takes into account that the control difference at the input of the first controller is also influenced by exhaust packets of other cylinders Z1 to Z4 due to the different lengths of the outlets of the cylinders Z1 to Z4 towards the Exhaust probe 41 and a mixing of the exhaust gas packets of the individual cylinders Z1 to Z4 in the area the exhaust gas probe 41. Subsequently, the thus corrected first estimated value EST1 is fed to a summing point S2. Alternatively, however, the first estimate EST1 may also be fed directly from the block B3 to the summing point S2.

Ein Block B5 umfasst einen zweiten Regler, dessen Regeldifferenz der erste Schätzwert EST1 ist und der als P-Regler ausgebildet ist, also einen Proportional-Regelparameter hat. Die Stellgröße des zweiten Reglers ist ein zylinderindividueller Lambdaregelfaktor LAM_FAC_I. Dieser zylinderindividuelle Lambdaregelfaktor LAM_FAC_I wird bevorzugt über einen Block B6, der dem Block B4 entspricht, mittels eines weiteren Wichtungsfaktors korrigiert, und dann einem Block B7 zugeführt, der ein PT1-Filter umfasst, das den zylinderindividuellen Lambdaregelfaktor LAM_FAC_I filtert und so an seinem Ausgang einen zweiten Schätzwert EST2 zur Verfügung stellt. In der Summierstelle S2 wird der Schätzwert D_LAM_I_EST der zylinderindividuellen Luft/Kraftstoff-Verhältnis Abweichung ermittelt aus der Differenz des ersten und zweiten Schätzwertes EST1, EST2.A block B5 comprises a second controller whose control difference is the first estimated value EST1 and which is designed as a P controller, ie has a proportional control parameter. The manipulated variable of the second controller is a cylinder-specific lambda control factor LAM_FAC_I. This cylinder-specific lambda control factor LAM_FAC_I is preferably corrected via a block B6, which corresponds to the block B4, by means of a further weighting factor, and then fed to a block B7 which comprises a PT1 filter which filters the cylinder-specific lambda control factor LAM_FAC_I and thus at its output a second Estimate EST2 provides. In the summing point S2, the estimated value D_LAM_I_EST of the cylinder-specific air / fuel ratio deviation is determined from the difference of the first and second estimated values EST1, EST2.

In einem Block B8 ist ein dritter Regler vorgesehen, dessen Führungsgröße ein für alle Zylinder der Brennkraftmaschine vorgegebenes Luft/Kraftstoff-Verhältnis ist und dessen Regelgröße das mittlere Luft/Kraftstoff-Verhältnis LAM_MW ist. Die Stellgröße des dritten Reglers ist ein Lambdaregelfaktor LAM_FAC_ALL. Der dritte Regler hat somit die Aufgabe, dass betrachtet über alle Zylinder Z1 bis Z4 der Brennkraftmaschine das vorgegebene Luft/Kraftstoff-Verhältnis eingestellt wird. Alternativ kann dies auch dadurch erreicht werden, dass in dem Block B2 der Istwert D_LAM_I der zylinderindividuellen Luft/Kraftstoff-Verhältnis Abweichung aus der Differenz des für alle Zylinder Z1 bis Z4 der Brennkraftmaschine vorgegebenen Luft/Kraftstoff-Verhältnisses und des zylinderindividuellen Luft/Kraftstoff-Verhältnisses LAM_I ermittelt wird. In diesem Fall kann dann der dritte Regler des Blocks B8 entfallen.In a block B8, a third controller is provided whose command variable is a predetermined for all cylinders of the internal combustion engine air / fuel ratio and the controlled variable is the average air / fuel ratio LAM_MW. The manipulated variable of the third controller is a lambda control factor LAM_FAC_ALL. The third controller thus has the task that viewed over all cylinders Z1 to Z4 of the internal combustion engine, the predetermined air / fuel ratio is adjusted. Alternatively, this can also be achieved in that in the block B2 the actual value D_LAM_I of the cylinder-specific air / fuel ratio deviation from the difference of the predetermined for all cylinders Z1 to Z4 of the internal combustion engine air / fuel ratio and the cylinder-individual air / fuel ratio LAM_I is determined. In In this case, then the third controller of the block B8 can be omitted.

In einem Block B9 wird eine zuzumessende Kraftstoffmasse MFF abhängig von einem Luftmassenstrom MAF in den jeweiligen Zylinder Z1 bis Z4 und gegebenenfalls der Drehzahl N und einem Sollwert LAM_SP des Luft/Kraftstoff-Verhältnisses für alle Zylinder Z1-Z4 ermittelt.In a block B9, a fuel mass MFF to be metered is determined as a function of an air mass flow MAF in the respective cylinders Z1 to Z4 and optionally the rotational speed N and a target value LAM_SP of the air / fuel ratio for all cylinders Z1-Z4.

In der Multiplizierstelle M1 wird eine korrigierte zuzumessende Kraftstoffmasse MFF_COR durch Multiplizieren der zuzumessenden Kraftstoffmasse MFF, des Lambdaregelfaktors LAM_FAC_ALL und des zylinderindividuellen Lambdaregelfaktors LAM_FAC_I ermittelt. Abhängig von der korrigierten zuzumessenden Kraftstoffmasse MFF_COR wird dann ein Stellsignal erzeugt, mit dem das jeweilige Einspritzventil 34 angesteuert wird.In the multiplier M1, a corrected fuel mass MFF_COR to be metered is determined by multiplying the fuel mass MFF to be metered, the lambda control factor LAM_FAC_ALL and the cylinder-specific lambda control factor LAM_FAC_I. Depending on the corrected fuel mass MFF_COR to be metered, an actuating signal is then generated with which the respective injection valve 34 is activated.

Neben der in dem Blockschaltbild der Figur 2 dargestellten Reglerstruktur sind für jeden weiteren Zylinder Z1 bis Z4 entsprechende Reglerstrukturen B_Z2 bis B_Z4 für die jeweiligen weiteren Zylinder Z2 bis Z4 vorgesehen.In addition to the block diagram of FIG. 2 controller structure shown are provided for each additional cylinder Z1 to Z4 corresponding control structures B_Z2 to B_Z4 for the respective further cylinder Z2 to Z4.

Durch den zweiten Schätzwert EST2 erfolgt eine Kompensation der Regelstreckendynamik, das heißt der Dynamik der Brennkraftmaschine in der Form, dass die Stelleingriffe des ersten und zweiten Reglers in die Ermittlung des Schätzwertes D_LAM_I_EST der zylinderindividuellen Luft/Kraftstoff-Verhältnis Abweichung mit einbezogen werden. Durch die Reglerstruktur und eine geeignete Parametrisierung der ersten und zweiten Regler kann sichergestellt werden, dass die bleibende Regelabweichung zwischen den tatsächlich in die einzelnen Zylinder Z1 bis Z4 zugemessenen Kraftstoffmassen gegen null geht.The second estimated value EST2 compensates the control path dynamics, that is to say the dynamics of the internal combustion engine in such a way that the control interventions of the first and second controllers are included in the determination of the estimated value D_LAM_I_EST of the cylinder-specific air / fuel ratio deviation. By means of the controller structure and a suitable parameterization of the first and second controllers, it can be ensured that the remaining control deviation between the fuel masses actually metered into the individual cylinders Z1 to Z4 approaches zero.

Dadurch, dass der zweite Regler, dessen Regelgröße der erste Schätzwert EST1 ist, keinen weiteren I-Anteil hat wird eine Erhöhung der möglichen Regelgeschwindigkeit und eine Steigerung der Robustheit der Regelstruktur erreicht im Vergleich zu dem Fall, in dem der zweite Regler zusätzlich eine I-Anteil hat.Because the second controller, whose controlled variable is the first estimated value EST1, has no further I-component, an increase in the possible control speed and an increase in the robustness of the control structure is achieved in comparison to the case in which the second controller additionally has an I-component. Share has.

Der Wichtungsfaktor des Blocks B6 kann auch mit einem negativen Vorzeichen versehen sein. Dies hat dann zur Folge, dass der zweite Schätzwert EST2 in der Summierstelle S2 addiert wird.The weighting factor of the block B6 may also be provided with a negative sign. This has the consequence that the second estimated value EST2 is added in the summing point S2.

Bevorzugt sind die Wichtungsfaktoren der Blöcke B4 und/oder B6 auch abhängig von der Lastgröße, die bevorzugt der Luftmassenstrom MAF in den jeweiligen Zylinder Z1-Z4 ist und/oder die Drehzahl N ist.Preferably, the weighting factors of the blocks B4 and / or B6 are also dependent on the load size, which is preferably the air mass flow MAF in the respective cylinder Z1-Z4 and / or the rotational speed N is.

Ferner kann auch der Regelparameter des zweiten Reglers, also hier der Proportional-Regelparameter, abhängig sein von der Lastgröße, die bevorzugt der Luftmassenstrom MAF in den jeweiligen Zylinder Z1-Z4 ist und/oder die Drehzahl N ist. Dadurch kann dann die Regelgüte einfach erhöht werden, da die unterschiedliche Vermischung der Abgaspakete die aus den einzelnen Verbrennungen des Luft/Kraftstoff-Gemisches in den jeweiligen Zylindern Z1-Z4 resultieren, berücksichtigt wird.Furthermore, the control parameter of the second regulator, that is to say the proportional control parameter here, can also be dependent on the load variable, which is preferably the air mass flow MAF in the respective cylinder Z1-Z4 and / or the rotational speed N. As a result, the control quality can then be increased simply, since the different mixing of the exhaust gas packages resulting from the individual combustions of the air / fuel mixture in the respective cylinders Z1-Z4 is taken into account.

Eine alternative Ausführungsform der Steuereinrichtung 6 ist anhand des Blockschaltbildes der Figur 3 beschrieben, wobei nur auf die Unterschiede zu dem Blockschaltbild gemäß Figur 2 im folgenden eingegangen wird. Der zweite Regler in einem Block B5' hat im Unterschied zu dem zweiten Regler der Figur 2 als Regeldifferenz die Differenz des Istwertes D_LAM_I und des Schätzwertes LAM_I_EST der zylinderindividuellen Luft/Kraftstoff-Verhältnis Abweichung. Der zweite Regler des Blocks B5' hat ferner einen weiteren Integral-Regelparameter, der bevorzugt so gewählt ist, dass er dem Produkt aus dem Integral-Regelparameter des ersten Reglers des Blocks B3 und dem Proportional-Regelparameter des zweiten Reglers des Blocks B5 in Figur 2 entspricht. Die Stellgröße des zweiten Reglers ist ebenfalls der zylinderindividuellen Lambdaregelfaktor LAM_FAC_I.An alternative embodiment of the control device 6 is based on the block diagram of FIG. 3 , with only the differences from the block diagram according to FIG. 2 will be discussed below. The second controller in a block B5 ', unlike the second controller, has the FIG. 2 as a control difference, the difference between the actual value D_LAM_I and the estimated value LAM_I_EST of the cylinder-specific air / fuel ratio deviation. The second controller of block B5 'also has another integral control parameter, which is preferably selected to be the product of the integral control parameter of the first controller of the block B3 and the proportional control parameter of the second controller of the block B5 in FIG FIG. 2 equivalent. The manipulated variable of the second controller is likewise the cylinder-specific lambda control factor LAM_FAC_I.

Sowohl der zylinderindividuelle Lambdaregelfaktor LAM_FAC_I als auch der Lambdaregelfaktor LAM_FAC_ALL können auch entsprechende additive Korrekturwerte für die zuzumessende Kraftstoffmasse MFF sein.Both the cylinder-specific lambda control factor LAM_FAC_I and the lambda control factor LAM_FAC_ALL can also be corresponding additive correction values for the fuel mass MFF to be metered.

Claims (6)

  1. Device for controlling an internal combustion engine with a plurality of cylinders (Z1 ... Z4) and injection valves (34), which meter fuel, assigned to the cylinders, with an exhaust gas probe (41) arranged in an exhaust gas manifold (4) and having a measurement signal which is characteristic of the air/fuel ratio in the respective cylinder (Z1 ... Z4), with which
    - a first regulator is provided, the regulating difference of which is a difference between an actual value (D_LAM_I) of a cylinder-specific deviation of the air/fuel ratio from a prdefinable air/fuel ratio and an estimated value (D_LAM_I_EST) of the cylinder-specific deviation of the air/fuel ratio from a predefinable air/fuel ratio, which has an integral regulating parameter and the manipulated variable of which is a first estimated value (EST1),
    - a second regulator is provided, the regulating difference of which is the first estimated value (EST1) and which has a proportional regulating parameter and the manipulated variable of which is a cylinder-specific lambda control factor (LAM_FAC_I),
    - a PT1 filter is provided, by means of which a second estimated value (EST2) is determined by PT1 filtering of the cylinder-specific lambda control factor (LAM_FAC_I),
    - a unit is provided, which determines the estimated value (D_LAM_I_EST) of the cylinder-specific deviation of the air/fuel ratio from the difference between the first and second estimated values (EST1, EST2),
    - a block is provided, which determines a fuel mass (MFF) to be supplied, which is to be supplied to the respective cylinder (Z1-Z4) in the internal combustion engine, as a function of a load variable and in which the fuel mass (MFF) to be supplied is corrected as a function of the cylinder-specific lambda control factor (LAM_FAC_I) and which generates an actuating signal to control the injection valve (34) as a function of the corrected fuel mass (MFF_COR) to be supplied.
  2. Device for controlling an internal combustion engine with a plurality of cylinders (Z1 ... Z4) and injection valves (34), which meter fuel, assigned to the cylinders, with an exhaust gas probe (41) arranged in an exhaust gas manifold (4) and having a measurement signal which is characteristic of the air/fuel ratio in the respective cylinder (Z1 ... Z4), with which
    - a first regulator is provided, the regulating difference of which is a difference between an actual value (D_LAM_I) of a cylinder-specific deviation of the air/fuel ratio from a predefinable air/fuel ratio and an estimated value (D_LAM_I_EST) of the cylinder-specific deviation of the air/fuel ratio from a predefinable air/fuel ratio, which has an integral regulating parameter and the manipulated variable of which is a first estimated value (EST1),
    - a second regulator is provided, the regulating difference of which is a difference between an actual value (D_LAM_I) and an estimated value (D_LAM_I_EST) of a cylinder-specific deviation of the air/fuel ratio from a predefinable air/fuel ratio, which has a further integral regulating parameter and the manipulated variable of which is a cylinder-specific lambda control factor (LAM_FAC_I),
    - a PT1 filter is provided, by means of which a second estimated value (EST2) is determined by PT1 filtering of the cylinder-specific lambda control factor (LAM_FAC_I),
    - a unit is provided, which determines the estimated value (D_LAM_I_EST) of the cylinder-specific deviation of the air/fuel ratio from the difference between the first and second estimated values (EST1, EST2),
    - a block is provided, which determines a fuel mass (MFF) to be supplied, which is to be supplied to the respective cylinder (Z1-Z4) in the internal combustion engine, as a function of a load variable and in which the fuel mass (MFF) to be supplied is corrected as a function of the cylinder-specific lambda control factor (LAM_FAC_I) and which generates an actuating signal to control the injection valve (34) as a function of the corrected fuel mass (MFF_COR) to be supplied.
  3. Device according to one of the preceding claims, characterized in that a block (B4) is provided, which adjusts the first estimated value (EST1) by means of a weighting factor before it is supplied to the unit and that a further block (B6) is provided, which adjusts the cylinder-specific lambda control factor (LAM_FAC_I) by means of a further weighting factor, before it is supplied to the PT1 filter.
  4. Device according to one of the preceding claims, characterized in that the predefinable air/fuel ratio is a mean air/fuel ratio (LAM_MW) of all cylinder-specific air/fuel ratios.
  5. Device according to one of the preceding claims, characterized in that a third regulator is provided, the reference variable of which is an air/fuel ratio predefined for all the cylinders in the internal combustion engine, the controlled variable of which is the mean air/fuel ratio of all cylinder-specific air/fuel ratios and the manipulated variable of which is a lambda control factor (LAM_FAC_ALL).
  6. Device according to one of the preceding claims, characterized in that the proportional regulating parameter or the further integral regulating parameter of the second regulator is predefined as a function of load.
EP04820452A 2003-12-16 2004-11-10 Device for controlling an internal combustion engine Expired - Lifetime EP1608861B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10358988 2003-12-16
DE10358988A DE10358988B3 (en) 2003-12-16 2003-12-16 Fuel injection control for multi-cylinder IC engine using comparison of estimated fuel/air ratio with actual fuel air ratio for correcting injected fuel mass for each engine cylinder for individual lambda regulation
PCT/EP2004/052912 WO2005059342A1 (en) 2003-12-16 2004-11-10 Device for controlling an internal combustion engine

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EP1608861A1 EP1608861A1 (en) 2005-12-28
EP1608861B1 true EP1608861B1 (en) 2008-04-23

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JP4487971B2 (en) * 2006-04-24 2010-06-23 トヨタ自動車株式会社 Air-fuel ratio control device for internal combustion engine
DE102006033869B3 (en) * 2006-07-21 2008-01-31 Siemens Ag Method and device for diagnosing the cylinder-selective unequal distribution of a fuel-air mixture, which is supplied to the cylinders of an internal combustion engine
DE102008009034B3 (en) * 2008-02-14 2009-04-23 Audi Ag Internal combustion engine operating method for motor vehicle, involves correcting fuel mass to be measured depending on intermediate correction value until lambda adaptation value is adapted to start engine
EP2098709B1 (en) * 2008-03-04 2016-07-06 GM Global Technology Operations LLC A method for operating an internal combustion engine
DE102008058008B3 (en) 2008-11-19 2010-02-18 Continental Automotive Gmbh Device for operating an internal combustion engine
GB2487589B (en) * 2011-01-28 2017-10-11 Gm Global Tech Operations Llc Method for operating a diesel/natural-gas internal combustion engine
JP5616274B2 (en) * 2011-03-31 2014-10-29 本田技研工業株式会社 Air-fuel ratio control device
AT513359B1 (en) * 2012-08-17 2014-07-15 Ge Jenbacher Gmbh & Co Og Method for operating an internal combustion engine
DE102013220117B3 (en) * 2013-10-04 2014-07-17 Continental Automotive Gmbh Device for operating an internal combustion engine

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FR2775315B1 (en) * 1998-02-25 2000-05-05 Magneti Marelli France METHOD AND DEVICE FOR FAST SELF-ADAPTATION OF RICHNESS FOR AN INJECTION ENGINE WITH AN OXYGEN PROBE IN EXHAUST GASES
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US7284545B2 (en) 2007-10-23
DE10358988B3 (en) 2005-05-04
WO2005059342A1 (en) 2005-06-30
US20060260592A1 (en) 2006-11-23
DE502004006915D1 (en) 2008-06-05
EP1608861A1 (en) 2005-12-28

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