DE102023112703A1 - Method for emission-optimized control of an internal combustion engine - Google Patents

Abstract

The invention relates to a method for emission-optimized control of an internal combustion engine (10) in a motor vehicle (100). The method comprises the following steps:
- Determining an emission-optimal, maximum operating parameter of the internal combustion engine (10),
- determining a driving speed of the motor vehicle (100),
- Normalizing an emission component-dependent target to the determined driving speed,
- Limiting the operating parameter of the internal combustion engine (10) to a maximum operating parameter at which the speed-dependent emission component-dependent target is reached.
The invention further relates to an engine control unit (60), an internal combustion engine (10) and a motor vehicle (100) for carrying out such a method.

Description

The invention relates to a method for emission-optimized control of an internal combustion engine in a motor vehicle and to a motor vehicle with an internal combustion engine and an engine control unit for carrying out such a method according to the preamble of the independent patent claims.

Current and future increasingly stricter exhaust gas legislation places high demands on the raw emissions of combustion engines and the exhaust gas aftertreatment of combustion engines. The demands for further reductions in consumption and the further tightening of exhaust gas standards with regard to permissible emissions represent a challenge for engine developers. In gasoline engines, exhaust gas purification is carried out in the usual way via a three-way catalyst, as well as further catalysts upstream and downstream of the three-way catalyst and a particle filter. In order to monitor the exhaust emissions of a gasoline engine, exhaust gas sensors are installed in the exhaust system, which monitor the functionality of the exhaust gas aftertreatment components as part of an on-board diagnosis.

In order to meet the EU6 emissions standard for gasoline engines, exhaust aftertreatment systems have become widespread, which include one or more three-way catalysts and a particle filter. A three-way catalyst is a vehicle catalyst for the exhaust aftertreatment of internal combustion engines, in which carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC) are converted to carbon dioxide (CO ₂ ), molecular nitrogen (N ₂ ) and water vapor (H ₂ O). The name of the catalyst is derived from the simultaneous conversion of these three air pollutants. It is known that when the engine is warm, the limited pollutant components are emitted when the operation deviates from a stoichiometric combustion air ratio in the exhaust system, for example during dynamic load changes or after overrun cut-off.

The future Euro 7 emissions legislation requires distance-based and cumulative recording of individual emissions through on-board monitoring (OBM). These distance-based emissions are usually given in mg/km. This requires permanent determination of emissions, which can be done using sensors or models. Furthermore, with the introduction of the Euro 7 emissions legislation, the amount of ammonia (NH3) could also be legally limited in addition to the already limited exhaust components such as unburned hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx).

An emissions-critical operating state of an internal combustion engine can occur in particular when, after an operating phase of the internal combustion engine with overrun cut-off, the oxygen storage of the catalysts is at maximum load and a reduction of pollutants, in particular a reduction of nitrogen oxides, is not possible due to a lack of reducing agent, in particular due to unburned hydrocarbons in the exhaust gas flow of the internal combustion engine. In addition, in motor vehicles with a hybrid drive train, not only does the number of overrun phases increase due to the drive by the electric motor, but in addition the exhaust gas aftertreatment components can cool down below their light-off temperature when the motor vehicle is driven purely electrically, thus limiting the conversion of pollutant emissions.

One way to prevent such an operating state with a maximum loading of the oxygen storage of the exhaust aftertreatment component is a zero cam, which prevents the opening and closing of the valves during an overrun phase of the combustion engine and thus minimizes the oxygen input into the exhaust system during an overrun phase. However, such a solution involves additional effort in the design of the camshaft and/or the control of the valves and leads to an increase in the costs for the combustion engine.

From the DE 10 2016 224 135 A1 A method for reducing nitrogen oxide emissions from a diesel vehicle is known. In this process, sensors of the diesel vehicle are used to record first state variables of the diesel vehicle and a computing unit determines, depending on the first state variables, whether the nitrogen oxide emissions exceed a predetermined threshold, or the computing unit predicts, depending on the first state variables, whether the nitrogen oxide emissions will exceed the predetermined threshold. If an exceedance of the threshold is calculated or predicted, the computing unit determines an intervention in the current torque requirement of the diesel vehicle and/or an intervention in the current gear ratio or setting of a transmission of the diesel vehicle, which contributes to reducing the nitrogen oxide emissions to a value below the threshold.

The DE 10 2015 014 150 A1 describes a motor vehicle with at least one first drive motor, which is designed as an internal combustion engine, wherein the internal combustion engine has a plurality of variable adjustable control variables. The internal combustion engine also has at least one first sensor device, which is intended to detect at least one vehicle and/or ambient and/or environment-related state parameter and to provide a data value representing this. At least one actuating device is also provided, which is designed to change at least one of the variable control variables of the internal combustion engine. The internal combustion engine also comprises at least one control device, which is designed to process the data values of the first sensor device and to transmit a signal to the actuating device, wherein the control device is intended to receive and process the at least one provided vehicle and/or ambient and/or environment-related state parameter. Furthermore, a state model is to be determined taking these state parameters into account, wherein a vehicle behavior forecast is calculated using this state model. An emissions forecast is created from this vehicle behavior forecast, wherein the emissions forecast is evaluated using predetermined criteria and, based on the emissions forecast, a control value or tax rate for controlling the actuating device is derived.

From the DE 10 2021 110 738 A1 A method for operating an internal combustion engine, in particular for driving a motor vehicle, is known. The internal combustion engine is connected by its outlet to an exhaust system in which at least one exhaust gas catalyst with an oxygen storage capacity, in particular a three-way catalyst, is arranged. The internal combustion engine is operated in such a way that with the start of a fired operation of the internal combustion engine, which follows a non-fired overrun operation or a non-operation, the size of an exhaust gas mass flow generated by the internal combustion engine is temporarily controlled depending on the fill level of the oxygen storage.

The invention is based on the object of minimizing the emissions of an internal combustion engine and, in particular, avoiding or shortening emission-critical operating situations.

• - Ermitteln eines emissionsoptimalen, maximalen Betriebsparameter des Verbrennungsmotors,
• - Ermitteln einer Fahrgeschwindigkeit des Kraftfahrzeugs,
• - Normieren eines emissionskomponentenabhängigen Targets auf die ermittelte Fahrgeschwindigkeit,
• - Begrenzen des Betriebsparameters des Verbrennungsmotors auf einen maximalen Betriebsparameter, an dem das geschwindigkeitsabhängige emissionskomponentenabhängige Target erreicht wird.

The task is solved by a method for emission-optimized control of an internal combustion engine in a motor vehicle. The method comprises at least the following steps:

• - Determination of an emission-optimal, maximum operating parameter of the combustion engine,
• - Determining a driving speed of the motor vehicle,
• - Normalizing an emission component-dependent target to the determined driving speed,
• - Limiting the operating parameter of the internal combustion engine to a maximum operating parameter at which the speed-dependent emission component-dependent target is achieved.

In this context, an internal combustion engine is a heat engine that converts chemical energy into mechanical energy through combustion. Such an internal combustion engine can be designed as a reciprocating piston engine or a rotary piston engine. In this context, an emission component-dependent target is a limit value that determines how much of a certain limited emission component may be emitted per distance traveled by the motor vehicle.

In this context, an operating parameter is understood to mean, in particular but not exclusively, a torque, a power, a speed, a quantity of fresh air supplied to the combustion chamber of the internal combustion engine or a quantity of fuel injected.

The method according to the invention makes it possible to ensure that the route-related limit values for exhaust emissions are complied with depending on different operating situations of the motor vehicle, for example depending on the gear engaged, the load of the motor vehicle, attachments and superstructures that impair the aerodynamics, trailer operation or the like.

The features listed in the dependent claims enable advantageous further developments and improvements of the method specified in the independent claim for emission-optimized control of an internal combustion engine in a motor vehicle.

In a preferred embodiment of the invention, the operating parameter of the internal combustion engine is a torque, a power or a speed of the internal combustion engine. The control to a torque, a power or a speed is particularly simple and efficient in order to comply with an emissions target for the distance-related emissions of the internal combustion engine.

In a preferred embodiment of the invention, an emission target is defined for each limited exhaust gas component and an associated maximum torque is determined for each limited exhaust gas component, with the smallest maximum torque being selected. This ensures that the motor vehicle always complies with the valid route-related emission limits even under unfavorable boundary conditions.

In an advantageous embodiment of the method, it is provided that a conversion capability of the exhaust gas aftertreatment components is continuously determined and, depending on the determined conversion capability of the exhaust gas aftertreatment components, the maximum torque of the internal combustion engine, which is dependent on the emission component, is determined. In this context, an exhaust gas aftertreatment component is to be understood as a catalyst and filter, which at least temporarily retain at least one limited exhaust gas component. An exhaust gas aftertreatment component is therefore to be understood as, in particular but not exclusively, a three-way catalyst, a four-way catalyst, a particle filter, a NOx storage catalyst, an ammonia barrier catalyst, an oxidation catalyst or a catalyst for the selective, catalytic reduction of nitrogen oxides. By determining the conversion capability, it can be calculated whether sufficient conversion of the limited pollutants is possible at the current driving speed and the raw emissions generated at the current operating point.

A further improvement to the method provides for a separate conversion model to be created for each exhaust aftertreatment component. This makes it possible to calculate the tailpipe emissions precisely. In particular, such a model can be used to determine how much raw emissions are permissible at the current operating point of the combustion engine in order to achieve an emissions target for the vehicle.

It is particularly preferred if the conversion models of the individual exhaust gas aftertreatment components are linked to one another in such a way that emission breakthroughs downstream of the last active exhaust gas aftertreatment component can be predicted. The last active exhaust gas aftertreatment component is to be understood as the last exhaust gas component in the flow direction of an exhaust gas flow through the exhaust system of the internal combustion engine, which has reached its operating temperature required for the conversion or temporary storage of the pollutants, in particular a light-off temperature of a catalyst. By linking, not only the raw emissions of the internal combustion engine can be taken into account, but also secondary emissions, in particular ammonia, which only arises on a catalytically effective surface of an exhaust gas aftertreatment component and can be removed from the exhaust gas flow again by another exhaust gas aftertreatment component arranged downstream. This creates a more complex model for predicting emission-critical operating situations of the combustion engine, but one that is even more accurate, so that the control of the combustion engine can be further improved with regard to an emission-optimized torque.

In an advantageous embodiment of the method, the internal combustion engine is connected to an electric drive motor as part of a hybrid drive train, wherein the maximum torque of the internal combustion engine is limited absolutely, to the level of a maximum torque that can be compensated by the electric drive motor, or continuously between these two possibilities. In this context, a hybrid drive train is understood to mean a drive train that includes an internal combustion engine and at least one electric drive motor.

A further improvement to the method provides that the combustion engine is operated with a defined, emission-optimized torque when an emission-critical operating state is detected and that the power is adjusted by the electric drive motor of the hybrid drive train. The power adjustment can take place in both directions, i.e. the electric drive motor can provide additional power and torque as well as be towed by the combustion engine and work in generator mode to reduce the power and torque. Since the power adjustment of the electric drive motor can be controlled particularly easily and quickly, the combustion engine can be operated at an essentially constant, emission-optimized operating point.

It is particularly preferred if the emission-critical operating state is the emptying of an oxygen storage of a catalyst, in particular a three-way catalyst or a four-way catalyst, in the exhaust system of the internal combustion engine. While the oxygen storage of the catalyst is being emptyed, the internal combustion engine is operated with a slightly substoichiometric combustion air ratio in order to empty the oxygen storage. By fully However, in a constantly loaded oxygen storage tank, there is no reducing agent available for a short time to reduce the nitrogen oxide emissions of the combustion engine. Therefore, emptying the oxygen storage tank of a catalyst represents an emissions-critical operating condition.

In a further advantageous embodiment of the method, the oxygen load of the exhaust gas aftertreatment component is detected by a lambda probe arranged in the exhaust system downstream of the exhaust gas aftertreatment component. A lambda probe arranged downstream of the exhaust gas aftertreatment component enables a statement to be made with sufficient accuracy about the oxygen load of the exhaust gas aftertreatment component. This oxygen load can thus be determined in a simple and cost-effective manner. This allows the process for clearing the oxygen storage of the exhaust gas aftertreatment component to be further improved.

Alternatively, the emission-critical operating state can also be a regeneration of a particle filter in the exhaust system of the combustion engine. A regeneration of the particle filter is often accompanied by internal engine heating measures, which usually lead to an increase in the raw emissions of the combustion engine. Therefore, a regeneration of the particle filter can also represent an emission-critical operating state in which it is advantageous to limit the maximum torque of the combustion engine with regard to the emission targets.

In an advantageous embodiment of the method, the maximum torque is limited by the sum of the emission-optimized torque of the combustion engine and the maximum torque of the electric drive motor. This can prevent the emission targets from being violated by a requirement for the combustion engine that is too high in emissions. It is precisely the generally relatively high maximum torque of the electric drive motor that makes it possible to reflect the majority of the driver's wishes without a critical increase in emissions.

It is particularly preferred if a torque and/or power requirement by the driver, which is above the sum of the emission-optimized torque of the combustion engine and the maximum torque of the electric drive motor, is implemented with a time delay. A time-delayed implementation can avoid short-term emission peaks that can only be inadequately converted by the exhaust gas aftertreatment components. Furthermore, the conversion behavior can be improved, in particular by adjusting the oxygen loading in the time delay period, so that the torque and/or power requirement can then be mapped without violating the emission targets of the combustion engine.

A further aspect of the invention relates to an engine control unit for an internal combustion engine with a memory unit and a computing unit, as well as a computer program code stored in the memory unit, wherein the engine control unit is set up to carry out a method described in the previous sections when the computer program code is executed by the computing unit. Such an engine control unit makes it possible to control an internal combustion engine and an exhaust aftertreatment system of the internal combustion engine in such a way that a method according to the invention for emission-optimized control of an internal combustion engine can be carried out in order to minimize the emissions of the internal combustion engine.

A further aspect of the invention relates to an internal combustion engine with at least one combustion chamber, wherein a fuel injector for injecting fuel into the combustion chamber and a spark plug for igniting a combustible fuel-air mixture are arranged on the combustion chamber. The internal combustion engine is connected by its outlet to an exhaust system in which at least one exhaust gas aftertreatment component, in particular a three-way catalyst and/or a four-way catalyst, is arranged. The internal combustion engine is also connected to an engine control unit described in the previous section. In such an internal combustion engine, the emissions, in particular the route-related, limited exhaust gas components, can be minimized by emission-optimized operation and the best possible exhaust gas aftertreatment.

A further aspect of the invention relates to a motor vehicle with a hybrid drive train, which comprises an electric drive motor and an internal combustion engine as described in the previous section. The method according to the invention enables a reduction in emissions, particularly in motor vehicles with a hybrid drive train with an electric drive motor and an internal combustion engine, since emission-critical operating points can be avoided or at least shortened and thus the tailpipe emissions of the motor vehicle can be reduced.

It is particularly preferred if the hybrid drive train is designed as a plug-in hybrid. Since in plug-in hybrids, due to a comparatively large battery, an operating state is particularly often selected in which the electric drive motor serves as the sole drive source compared to other hybrid systems, plug-in hybrids can be particularly critical with regard to the availability of the exhaust gas aftertreatment components, since these cool down in electric driving mode and/or the oxygen storage of the exhaust gas aftertreatment components is charged in purely electric driving mode. Therefore, it is particularly helpful in such plug-in hybrids to reduce emissions by means of a method according to the invention for emission-optimized control of an internal combustion engine.

The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless stated otherwise in individual cases.

• 1 ein bevorzugtes Ausführungsbeispiel für ein hybriden Antriebsstrang eines Kraftfahrzeugs mit einem fremdgezündeten Verbrennungsmotor und einem elektrischen Antriebsmotor sowie einem Abgasnachbehandlungssystem;
• 2 ein weiteres bevorzugtes Ausführungsbeispiel für einen fremdgezündeten Verbrennungsmotor zur Durchführung eines erfindungsgemäßen Verfahrens, und
• 3 ein Ablaufdiagramm zur Durchführung eines erfindungsgemäßen Verfahrens zur emissionsoptimierten Steuerung eines Verbrennungsmotors.

The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show:

• 1 a preferred embodiment of a hybrid drive train of a motor vehicle with a spark-ignition internal combustion engine and an electric drive motor as well as an exhaust aftertreatment system;
• 2 a further preferred embodiment of a spark-ignition internal combustion engine for carrying out a method according to the invention, and
• 3 a flow chart for carrying out a method according to the invention for emission-optimized control of an internal combustion engine.

1 shows a schematic representation of a hybrid drive train 70 of a motor vehicle 100 with a spark-ignited internal combustion engine 10 and an electric drive motor 72 as well as an exhaust aftertreatment system for the spark-ignited internal combustion engine 10. The spark-ignited internal combustion engine 10 and the electric drive motor 72 are connected via a transmission 76 to a drive shaft 78, which drives at least one driven axle 74 of the motor vehicle 100. The electric drive motor 72 is connected to a battery 80, which supplies the electric drive motor 72 with electrical current. The motor vehicle 100 is preferably designed as a plug-in hybrid 84 and has an electrical connection 82, via which the battery 80 can be charged with an external charging cable.

The spark-ignited internal combustion engine 10 is preferably designed as a direct-injection gasoline engine. The spark-ignited internal combustion engine 10 has several combustion chambers 12. A fuel injector 14 for injecting a fuel into the respective combustion chamber 12 is arranged on each of the combustion chambers 12. Furthermore, a spark plug 16 for igniting an ignitable fuel-air mixture in the respective combustion chamber 12 is arranged on each combustion chamber 12. The spark plug 16 can be designed as a hook spark plug or as a pre-chamber spark plug. The combustion chamber 12 is heated by a 1 not shown piston, which is slidably arranged in a cylinder of the internal combustion engine 10. The piston is connected via a connecting rod to a crankshaft of the internal combustion engine 10, wherein the connecting rod transfers an oscillating movement of the piston into a rotary movement of the crankshaft. The internal combustion engine 10 is connected with its inlet to a 1 not shown air supply system and connected with its outlet 18 to an exhaust system 20. Inlet valves and outlet valves are arranged on the combustion chambers 12, with which a fluidic connection from the air supply system to the combustion chambers 12 or from the combustion chambers 12 to the exhaust system 20 can be opened or closed.

The exhaust system 20 comprises an exhaust duct 42 in which a first exhaust gas aftertreatment component 24, in particular a three-way catalyst 30, is arranged close to the engine in the flow direction of an exhaust gas flow 58 of the internal combustion engine 10 through the exhaust system 20. The three-way catalyst 30 can have an electrical heating element for heating the three-way catalyst 30. Alternatively or additionally, the three-way catalyst 30 can have a NOx storage component. Downstream of the first exhaust gas aftertreatment component 24, a second exhaust gas aftertreatment component 26, in particular a particle filter 32, is arranged in the exhaust system 20, which is connected to the exhaust gases by means of a 1 not shown differential pressure sensor. Downstream of the second exhaust gas aftertreatment component 26, a third exhaust gas aftertreatment component 28, in particular a second three-way catalyst 30 or a four-way catalyst 34, is located in the exhaust system 20. The second three-way catalyst 30 can also additionally have a NOx storage component. As an alternative to the second three-way catalyst 30, the third exhaust gas aftertreatment component 28 can also be designed as a NOx storage catalyst 36 or comprise a NOx storage catalyst 36. Furthermore, the third exhaust gas aftertreatment component 28 can be designed as an ammonia barrier catalyst 38 or an ammonia barrier catalyst 38.

Downstream of the outlet 18 of the internal combustion engine 10 and upstream of the first exhaust aftertreatment component 24, a temperature sensor 54 for measuring the temperature of the exhaust gas flow 58 is arranged in the exhaust system 20. Downstream of the second exhaust aftertreatment component 26 and upstream of the third exhaust aftertreatment component 28, a second temperature sensor 54 for measuring the temperature of the exhaust gas flow 58 can be arranged in the exhaust system 20. Furthermore, a first lambda probe 44, in particular a broadband lambda probe 50, is arranged in the exhaust system 20 downstream of the outlet 18 and upstream of the first exhaust aftertreatment component 24. Downstream of the first exhaust aftertreatment component 24 and upstream of the second exhaust aftertreatment component 26, a second lambda probe 46 is arranged. The second lambda probe 46 is preferably designed as a jump probe 52 and serves to optimally utilize the oxygen storage capacity of the three-way catalyst 30 and thus ensure minimal emissions. Furthermore, this second lambda probe 46 can be used for diagnosis and to determine the activity of the three-way catalyst 30. If the second exhaust gas aftertreatment component 26 is designed as a particle filter 32 without oxygen storage capacity, the second lambda probe 46 can alternatively also be arranged downstream of the particle filter 32 and upstream of the third exhaust gas aftertreatment component 28. Optionally, a third lambda probe 48 can be arranged downstream of the second exhaust gas aftertreatment component 26 and upstream of the third exhaust gas aftertreatment component 28. Furthermore, the exhaust system 20 can comprise further sensors, in particular one or more exhaust gas sensors 56.

The internal combustion engine 10 is assigned an engine control unit 60 with a memory unit 62 and a computing unit 64. A computer program code 66 is stored in the memory unit 62, which, when the computer program code 66 is executed by the computing unit 64, carries out a method according to the invention for predicting exhaust emissions of the internal combustion engine 10. In addition, a data connection from the engine control unit 60 to an on-board monitoring unit 68 is provided. Alternatively, the on-board monitoring unit 68 can also be integrated into the engine control unit 60.

In 2 An alternative embodiment of a spark-ignited internal combustion engine 10 with an exhaust aftertreatment system is shown. The spark-ignited internal combustion engine 10 is preferably designed as a direct-injection gasoline engine. The spark-ignited internal combustion engine 10 has several combustion chambers 12. A fuel injector 14 for injecting a fuel into the respective combustion chamber 12 is arranged on each of the combustion chambers 12. Furthermore, a spark plug 16 for igniting an ignitable fuel-air mixture in the respective combustion chamber 12 is arranged on each combustion chamber 12. The spark plug 16 can be designed as a hook spark plug or as a pre-chamber spark plug. The combustion chamber 12 is heated by a 2 not shown piston, which is slidably arranged in a cylinder of the internal combustion engine 10. The piston is connected via a connecting rod to a crankshaft of the internal combustion engine 10, wherein the connecting rod transfers an oscillating movement of the piston into a rotary movement of the crankshaft. The internal combustion engine 10 is connected with its inlet to a 2 not shown air supply system and connected with its outlet 18 to an exhaust system 20. Inlet valves and outlet valves are arranged on the combustion chambers 12, with which a fluidic connection from the air supply system to the combustion chambers 12 or from the combustion chambers 12 to the exhaust system 20 can be opened or closed.

The exhaust system 20 comprises an exhaust duct 42 in which a turbine 22 of an exhaust turbocharger 40 is arranged in the flow direction of an exhaust gas flow 58 of the internal combustion engine 10 through the exhaust system 20, and downstream of the turbine 22 of the exhaust turbocharger 40 a first exhaust aftertreatment component 24, in particular a three-way catalyst 30, is arranged. The three-way catalyst 30 can have an electrical heating element for heating the three-way catalyst 30. Alternatively or additionally, the three-way catalyst 30 can have a NOx storage component. Downstream of the first exhaust aftertreatment component 24, a second exhaust aftertreatment component 26, in particular a particle filter 32, is arranged in the exhaust system 20, which has a 2 not shown differential pressure sensor can be monitored. Downstream of the second exhaust aftertreatment component 26, a third exhaust aftertreatment component 28, in particular a second three-way catalyst 30, a four-way catalyst 34, a NOx storage catalyst 36 or an ammonia blocking catalyst 38, is located in the exhaust system 20. The third exhaust aftertreatment component 28, in particular the second three-way catalyst 30, can also additionally have a NOx storage component and/or an ammonia blocking catalyst.

Downstream of the outlet 18 of the internal combustion engine 10 and upstream of the first A temperature sensor 54 for measuring the temperature of the exhaust gas flow 58 is arranged in the exhaust system 20 in the exhaust aftertreatment component 24. A second temperature sensor 54 for measuring the temperature of the exhaust gas flow 58 can be arranged in the exhaust system 20 downstream of the second exhaust aftertreatment component 26 and upstream of the third exhaust aftertreatment component 28. Furthermore, a first lambda probe 44, in particular a broadband lambda probe 50, is arranged in the exhaust system 20 downstream of the outlet 18 and upstream of the first exhaust aftertreatment component 24. A second lambda probe 46 is arranged downstream of the first exhaust aftertreatment component 24 and upstream of the second exhaust aftertreatment component 26. The second lambda probe 46 is preferably designed as a jump probe 52 and serves to optimally utilize the oxygen storage capacity of the three-way catalyst 30 and thus ensure minimal emissions. Furthermore, this second lambda probe 46 can be used for diagnosis and to determine the activity of the three-way catalyst 30. If the second exhaust gas aftertreatment component 26 is designed as a particle filter 32 without oxygen storage capacity, the second lambda probe 46 can alternatively also be arranged downstream of the particle filter 32 and upstream of the third exhaust gas aftertreatment component 28. Optionally, a third lambda probe 48 can be arranged downstream of the second exhaust gas aftertreatment component 26 and upstream of the third exhaust gas aftertreatment component 28. Furthermore, the exhaust system 20 can comprise further sensors, in particular one or more exhaust gas sensors 56.

The internal combustion engine 10 is assigned an engine control unit 60 with a memory unit 62 and a computing unit 64. A computer program code 66 is stored in the memory unit 62, which, when the computer program code 66 is executed by the computing unit 64, carries out a method according to the invention for predicting exhaust emissions of the internal combustion engine 10. In addition, a data connection from the engine control unit 60 to an on-board monitoring unit 68 is provided. Alternatively, the on-board monitoring unit 68 can also be integrated into the engine control unit 60.

In 3 is a flow chart for carrying out a method according to the invention for emission-optimized control of an internal combustion engine 10 in a motor vehicle 100. In a method step <200>, an emission-optimized, maximum torque of the internal combustion engine 10 is determined. In a method step <210>, a driving speed of the motor vehicle 10 is determined. In a method step <220> following the method steps <200> and <210>, an emission component-dependent target is standardized to the determined driving speed. In a method step <230>, an emission target is determined for each limited exhaust gas component, for which a limit value, in particular a distance-related limit value, for the limited exhaust gas component is not exceeded. The result is an emission-optimized torque of the internal combustion engine for the respective limited exhaust gas component, which must not be exceeded in order to comply with the applied emission targets. In a method step <240>, the smallest maximum torque of the internal combustion engine 10 is determined at which the emission targets for all limited exhaust gas components are reached and not exceeded. With this calculated torque, in a method step <250>, the torque of the internal combustion engine 10 can be limited to the maximum torque at which the speed-dependent emission component-dependent emission target is reached.

list of reference symbols

10

spark-ignited combustion engine

12

combustion chamber

14

fuel injector

16

spark plug

18

outlet

20

exhaust system

22

turbine

24

first exhaust aftertreatment component

26

second exhaust aftertreatment component

28

third exhaust aftertreatment component

30

three-way catalyst

32

particulate filter

34

four-way catalyst

36

NOx storage catalyst

38

ammonia barrier catalyst

40

exhaust turbocharger

42

exhaust duct

44

first lambda probe

46

second lambda sensor

48

third lambda probe

50

broadband lambda sensor

52

jump probe

54

temperature sensor

56

exhaust gas sensor

58

exhaust gas flow

60

engine control unit

62

storage unit

64

arithmetic unit

66

computer program code

68

On-board monitoring unit

70

hybrid powertrain

72

Electric drive motor

74

driven axle

76

transmission

78

drive shaft

80

battery

82

electrical connection

84

plug-in hybrid

100

motor vehicle

<200>

first procedural step

<210>

second procedural step

<220>

third procedural step

<230>

fourth procedural step

<240>

fifth procedural step

<250>

sixth procedural step

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 10 2016 224 135 A1 [0007]
• DE 10 2015 014 150 A1 [0008]
• DE 10 2021 110 738 A1 [0009]

Claims (15)

Method for emission-optimized control of an internal combustion engine (10) in a motor vehicle (100), comprising the following steps: - determining an emission-optimal, maximum operating parameter of the internal combustion engine (10), - determining a driving speed of the motor vehicle (100), - normalizing an emission component-dependent target to the determined driving speed, - limiting the operating parameter of the internal combustion engine (10) to a maximum operating parameter at which the speed-dependent emission component-dependent target is reached. Method for emission-optimized control of an internal combustion engine (10) according to claim 1 , wherein the operating parameter of the internal combustion engine (10) is a torque, a power or a speed of the internal combustion engine (10). Method for emission-optimized control of an internal combustion engine (10) according to claim 1 or 2 , whereby an emission target is defined for each limited exhaust gas component and an associated maximum torque is determined for each limited exhaust gas component, whereby the smallest maximum torque is selected. Method for emission-optimized control of an internal combustion engine (10) according to one of the Claims 1 until 3 , wherein a conversion capability of the exhaust gas aftertreatment components (24, 26, 28) is continuously determined and the emission component-dependent maximum torque of the internal combustion engine (10) is determined as a function of the determined conversion capability of the exhaust gas aftertreatment components (24, 26, 28). Method for emission-optimized control of an internal combustion engine (10) according to one of the Claims 1 until 4 , wherein a separate conversion model is formed for each exhaust gas aftertreatment component (24, 26, 28). Method for emission-optimized control of an internal combustion engine (10) according to claim 5 , wherein the conversion models of the individual exhaust aftertreatment components (24, 26, 28) are linked to one another in such a way that emission breakthroughs downstream of the last active exhaust aftertreatment component can be predicted. Method for emission-optimized control of an internal combustion engine (10) according to one of the Claims 1 until 6 , wherein the internal combustion engine (10) is connected to an electric drive motor (72) as part of a hybrid drive train (70), wherein the maximum torque of the internal combustion engine (10) is limited absolutely, to the level of a maximum torque that can be compensated by the electric drive motor (72), or continuously between these two possibilities. Method for emission-optimized control of an internal combustion engine (10) according to claim 7 , wherein the internal combustion engine (10) is operated with a defined, emission-optimized torque when an emission-critical operating state is detected and a power adjustment is carried out by the electric drive motor (72). Method for emission-optimized control of an internal combustion engine (10) according to claim 8 , wherein the emission-critical operating state is a clearing of an oxygen storage of a catalyst in the exhaust system (20) of the internal combustion engine (10). Method for emission-optimized control of an internal combustion engine (10) according to one of the Claims 6 until 9 , wherein the maximum torque is limited by the sum of the emission-optimized torque of the internal combustion engine (10) and the maximum torque of the electric drive motor (72). Method for emission-optimized control of an internal combustion engine (10) according to claim 10 , wherein a torque and/or load request by the driver, which is above the sum of the emission-optimized torque of the internal combustion engine (10) and the maximum torque of the electric drive motor (72), is implemented with a time delay. Engine control unit (60) for an internal combustion engine (10) with a memory unit (62) and a computing unit (64), as well as a computer program code (66) stored in the memory unit (62), wherein the engine control unit (60) is designed to carry out a method according to one of the Claims 1 until 11 to execute when the computer program code (66) is executed by the computing unit (64). Internal combustion engine (10) with at least one combustion chamber (12), wherein a fuel injector (14) for injecting a fuel into the combustion chamber (12) and a spark plug (16) for igniting a combustible fuel-air mixture are arranged on the combustion chamber (12), wherein the internal combustion engine (10) is connected with its outlet (18) is connected to an exhaust system (20) in which at least one exhaust aftertreatment component (24, 26, 28) is arranged, and to an engine control unit (60) according to claim 12 . Motor vehicle (100) with a hybrid drive train (70) comprising an electric drive motor (72) and an internal combustion engine (10) according to claim 13 . Motor vehicle (100) after claim 14 , wherein the hybrid drive train (70) is designed as a plug-in hybrid (84).

Images