DE202015008555U1 - Computer program for controlling an injector for injecting a reducing agent into an exhaust system of an internal combustion engine - Google Patents

Abstract

A computer program for controlling an injector (287) to inject a reductant (286) into an exhaust aftertreatment system (270) of an internal combustion engine (110) comprising program code that, when executed on a computer, performs the steps of: - determining a quantity of reductant stored in a selective catalytic reduction system (282) based on a first amount of reductant stored in a first selective catalytic reduction catalyst (283) of the selective catalytic reduction system (282) and a selective catalytic reduction selective catalytic reduction catalyst (284) Reduction system (282) stored second amount of reducing agent; - determining a setpoint of the reducing agent stored in the selective catalytic reduction system (282) as a function of a temperature value of a substrate (284 ') disposed in the second selective catalytic reduction catalyst (284); Calculating a difference between the amount of reducing agent and the desired value; - adjusting a reducing agent dose injected into the exhaust aftertreatment system (270) based on the calculated difference; and - actuating the injector (287) to inject the adjusted dose of reducing agent (286).

Description

TECHNICAL AREA

The present invention relates to a computer program for controlling an injector for injecting a reducing agent into an exhaust aftertreatment system of an internal combustion engine of a motor vehicle, typically a diesel engine, equipped with exhaust aftertreatment systems comprising selective catalytic reduction catalysts.

BACKGROUND

Selective catalytic reduction (SCR) systems designed to reduce nitrogen oxides (NOx) by nitrogen compounds can be incorporated into automotive combustion engines.

Known multi-component SCR systems, d. H. SCR systems, which include a direct coupled SCR catalyst on a filter (SCRoF) and an underfloor SCR catalyst, are more temperature efficient and result in a significant improvement in overall NOx conversion compared to one component SCR systems.

In order to maximize NOx conversion efficiency and minimize consumption of reducing agent (ie, urea aqueous solution) by the multi-component SCR systems in reducing emissions, it is necessary to control the amount of reductant injected into the exhaust flow upstream of the SCRoF improve.

In view of the above, an object of the present disclosure is to provide a solution to this problem.

These and other objects are achieved by the embodiments of the invention having the features described in the independent claims. The dependent claims describe preferred and / or particularly advantageous aspects.

SUMMARY

• – Bestimmen einer in einem selektiven katalytischen Reduktionssystem gespeicherten Reduktionsmittelmenge auf Basis einer in einem ersten Katalysator zur selektiven katalytischen Reduktion des selektiven katalytischen Reduktionssystems gespeicherten ersten Reduktionsmittelmenge und einer in einem zweiten Katalysator zur selektiven katalytischen Reduktion des selektiven katalytischen Reduktionssystems gespeicherten zweiten Reduktionsmittelmenge;
• – Bestimmen eines Sollwerts des in dem selektiven katalytischen Reduktionssystem gespeicherten Reduktionsmittels als Funktion eines Temperaturwerts eines im zweiten Katalysator zur selektiven katalytischen Reduktion angeordneten Substrats;
• – Berechnen einer Differenz zwischen der Reduktionsmittelmenge und dem Sollwert;
• – Anpassen einer in das Abgasnachbehandlungssystem eingespritzten Reduktionsmitteldosis auf Basis der berechneten Differenz; und
• – Betätigen des Injektors, um die angepasste Reduktionsmitteldosis einzuspritzen.

One embodiment of the disclosure provides a computer program for controlling an injector for injecting a reductant into an exhaust aftertreatment system of an internal combustion engine that includes program code that, when executed on a computer, performs the following steps:

• Determining a quantity of reductant stored in a selective catalytic reduction system based on a first amount of reductant stored in a first catalyst for selective catalytic reduction of the selective catalytic reduction system and a second amount of reductant stored in a second catalyst for selective catalytic reduction of the selective catalytic reduction system;
• Determining a set point of the reducing agent stored in the selective catalytic reduction system as a function of a temperature value of a substrate disposed in the second selective catalytic reduction catalyst;
• Calculating a difference between the amount of reducing agent and the desired value;
• Adjusting a reducing agent dose injected into the exhaust aftertreatment system based on the calculated difference; and
• Actuate the injector to inject the adjusted reductant dose.

Thanks to this solution, it is possible to improve the control of the reducing agent dose injected upstream of the first SCR catalyst of a multicomponent SCR system into the exhaust stream, to maximize the NOx conversion of the SCR system and to pass through the SCR system to the outside Minimize the amount of ammonia released.

In one embodiment, the setpoint may be calculated as a sum of a first setpoint of the reductant stored in the first selective catalytic reduction catalyst and a product of a second setpoint of the reductant stored in the second selective catalytic reduction catalyst and a multiplier based on the temperature value of the in the second catalyst for selective catalytic reduction arranged substrate based.

Thanks to this solution, it is possible to control the amount of reducing agent injected into the exhaust gas flow upstream of the first SCR catalytic converter of a multicomponent SCR system and to correct it with low calibration effort and low computing power. In fact, known models of reducing agent dose injected into a one-component SCR system can be readily adapted to control the dose of reducing agent injected into a multi-component SCR system.

According to one embodiment, the amount of reductant may be as a sum of the first amount of reductant and a product of the second amount of reductant and a second Multiplier can be calculated, which is based on the temperature value of the arranged in the second catalyst for selective catalytic reduction substrate.

Thanks to this solution, it is possible to control the reductant dose injected upstream of the first SCR catalyst into the exhaust stream as a function of the maximum storage capacity of the SCR system at the actual temperature of the SCR catalysts of the SCR system.

According to one embodiment, the first multiplier may be equal to the second multiplier.

Thanks to this solution, the determination of the setpoint can be carried out with low calibration effort and low computing power.

In another embodiment, the step of determining the first setpoint may include the step of estimating the first setpoint based on a temperature of a first substrate disposed in the first selective catalytic reduction catalyst and a mass flow rate of the exhaust gas flowing through the first selective catalytic reduction catalyst.

Thanks to this solution, the first set point can be determined taking into account the most important parameters that influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the first SCR catalyst.

In another embodiment, the step of determining the second setpoint may include the step of estimating the second setpoint based on a temperature of the substrate disposed in the second selective catalytic reduction catalyst and a mass flow rate of the exhaust gas flowing through the second selective catalytic reduction catalyst.

By virtue of this solution, the second setpoint can be determined taking into account the most important parameters which affect NOx conversion and the resulting storage of reductant (i.e., ammonia) in the second SCR catalyst.

According to another embodiment, the step of determining the first amount may include the step of estimating the first amount based on a temperature of the exhaust gas entering the first catalyst for selective catalytic reduction, a mass flow rate of the exhaust gas flowing through the first catalyst for selective catalytic reduction, and a Nitrogen oxide content in the exhaust gas upstream of the first catalyst for selective catalytic reduction include.

Thanks to this solution, the first quantity can be determined taking into account the most important parameters that influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the first SCR catalyst.

In another embodiment, the step of determining the second amount may include the step of estimating the second amount based on a nitrogen oxide level in the exhaust upstream of the second selective catalytic reduction catalyst and upstream of the first selective catalytic reduction catalyst and upstream of the amount of reductant in the exhaust from the second catalyst for selective catalytic reduction and upstream of the first catalyst for selective catalytic reduction.

Thanks to this solution, the second quantity can be determined taking into account the most important parameters which influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the second SCR catalyst.

The present solution may also be implemented in the form of a computer program product comprising a carrier on which the computer program is stored. In particular, the present invention may be embodied in the form of a device for controlling an injector for injecting a reducing agent into an exhaust pipe of an internal combustion engine comprising an electronic control unit, a data carrier connected to the electronic control unit and the computer program stored in the data carrier. Another embodiment may provide an electromagnetic signal that is modulated to carry a sequence of data bits representing the computer program.

• – ein Abgasnachbehandlungssystem, umfassend ein selektives katalytisches Reduktionssystem mit einem ersten Katalysator zur selektiven katalytischen Reduktion und einem zweiten Katalysator zur selektiven katalytischen Reduktion, der in Fluidverbindung mit dem ersten Katalysator zur selektiven katalytischen Reduktion und steht und stromabwärts davon angeordnet ist, und einen Injektor, der in Fluidverbindung mit einem Reduktionsmittel steht und dafür ausgelegt ist, eine Reduktionsmitteldosis stromaufwärts vom ersten Katalysator zur selektiven katalytischen Reduktion in das Abgasnachbehandlungssystem einzuspritzen;
• – ein Steuergerät, das dafür ausgelegt ist: – eine in dem selektiven katalytischen Reduktionssystem gespeicherte Reduktionsmittelmenge auf Basis einer im ersten Katalysator zur selektiven katalytischen Reduktion gespeicherten ersten Reduktionsmittelmenge und einer im zweiten Katalysator zur selektiven katalytischen Reduktion gespeicherten zweiten Reduktionsmittelmenge zu bestimmen; – einen Sollwert des in dem selektiven katalytischen Reduktionssystem gespeicherten Reduktionsmittels als Funktion eines Temperaturwerts eines im zweiten Katalysator zur selektiven katalytischen Reduktion angeordneten Substrats zu bestimmen; – eine Differenz zwischen der Reduktionsmittelmenge und dem Sollwert zu berechnen; – die in das Abgasnachbehandlungssystem eingespritzte Reduktionsmitteldosis auf Basis der berechneten Differenz anzupassen; und – den Injektor zu betätigen, um die angepasste Reduktionsmitteldosis einzuspritzen.

Another embodiment having substantially the same effects as the computer program described above provides an internal combustion engine comprising:

• An exhaust aftertreatment system comprising a selective catalytic reduction system comprising a first selective catalytic reduction catalyst and a second selective catalytic reduction catalyst in fluid communication with and disposed downstream of the first selective catalytic reduction catalyst and an injector in fluid communication with a Reducing agent is and is designed to inject a reducing agent dose upstream of the first catalyst for selective catalytic reduction in the exhaust aftertreatment system;
• A controller adapted to: determine a quantity of reducing agent stored in the selective catalytic reduction system based on a first amount of reducing agent stored in the first selective catalytic reduction catalyst and a second quantity of reducing agent stored in the second selective catalytic reduction catalyst; To determine a target value of the reducing agent stored in the selective catalytic reduction system as a function of a temperature value of a substrate disposed in the second selective catalytic reduction catalyst; To calculate a difference between the amount of reducing agent and the desired value; To adjust the amount of reducing agent injected into the exhaust aftertreatment system based on the calculated difference; and - actuating the injector to inject the adjusted reductant dose.

Another embodiment of the solution provides a motor vehicle system equipped with an internal combustion engine as disclosed above.

• – Bestimmen einer in einem selektiven katalytischen Reduktionssystem gespeicherten Reduktionsmittelmenge auf Basis einer in einem ersten Katalysator zur selektiven katalytischen Reduktion des selektiven katalytischen Reduktionssystems gespeicherten ersten Reduktionsmittelmenge und einer in einem zweiten Katalysator zur selektiven katalytischen Reduktion des selektiven katalytischen Reduktionssystems gespeicherten zweiten Reduktionsmittelmenge;
• – Bestimmen eines Sollwerts des in dem selektiven katalytischen Reduktionssystem gespeicherten Reduktionsmittels als Funktion eines Temperaturwerts eines im zweiten Katalysator zur selektiven katalytischen Reduktion angeordneten Substrats;
• – Berechnen einer Differenz zwischen der Reduktionsmittelmenge und dem Sollwert;
• – Anpassen einer in das Abgasnachbehandlungssystem eingespritzten Reduktionsmitteldosis auf Basis der berechneten Differenz; und
• – Betätigen des Injektors, um die angepasste Reduktionsmitteldosis einzuspritzen.

A further embodiment of the solution provides a method for controlling an injector for injecting a reducing agent into an exhaust gas aftertreatment system of an internal combustion engine, comprising the following steps:

• Determining a quantity of reductant stored in a selective catalytic reduction system based on a first amount of reductant stored in a first catalyst for selective catalytic reduction of the selective catalytic reduction system and a second amount of reductant stored in a second catalyst for selective catalytic reduction of the selective catalytic reduction system;
• Determining a set point of the reducing agent stored in the selective catalytic reduction system as a function of a temperature value of a substrate disposed in the second selective catalytic reduction catalyst;
• Calculating a difference between the amount of reducing agent and the desired value;
• Adjusting a reducing agent dose injected into the exhaust aftertreatment system based on the calculated difference; and
• Actuate the injector to inject the adjusted reductant dose.

Thanks to this solution, it is possible to improve the control of the reducing agent dose injected upstream of the first SCR catalyst of a multicomponent SCR system into the exhaust stream, to maximize the NOx conversion of the SCR system and to pass through the SCR system to the outside Minimize the amount of ammonia released.

In one embodiment, the setpoint may be calculated as a sum of a first setpoint of the reductant stored in the first selective catalytic reduction catalyst and a product of a second setpoint of the reductant stored in the second selective catalytic reduction catalyst and a multiplier based on the temperature value of the in the second catalyst for selective catalytic reduction arranged substrate based.

Thanks to this solution, it is possible to control the amount of reducing agent injected into the exhaust gas flow upstream of the first SCR catalytic converter of a multicomponent SCR system and to correct it with low calibration effort and low computing power. In fact, known models of reducing agent dose injected into a one-component SCR system can be readily adapted to control the dose of reducing agent injected into a multi-component SCR system.

According to one embodiment, the amount of reductant may be calculated as a sum of the first reductant amount and a product of the second reductant amount and a second multiplier based on the temperature value of the substrate disposed in the second selective catalytic reduction catalyst.

Thanks to this solution, it is possible to control the amount of reducing agent injected into the exhaust gas stream upstream of the first SCR catalyst as a function of the maximum storage capacity of the SCR system at the actual temperature of the SCR catalysts of the SCR system.

According to one embodiment, the first multiplier may be equal to the second multiplier.

Thanks to this solution, the determination of the setpoint can be carried out with low calibration effort and low computing power.

In another embodiment, the step of determining the first setpoint may include the step of estimating the first setpoint based on a temperature of a first substrate disposed in the first selective catalytic reduction catalyst and a mass flow rate of the exhaust gas flowing through the first selective catalytic reduction catalyst.

Thanks to this solution, the first set point can be determined taking into account the most important parameters that influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the first SCR catalyst.

In another embodiment, the step of determining the second setpoint may include the step of estimating the second setpoint based on a temperature of the substrate disposed in the second selective catalytic reduction catalyst and a mass flow rate of the exhaust gas flowing through the second selective catalytic reduction catalyst.

Thanks to this solution, the second set point can be determined taking into account the most important parameters that influence the NOx conversion and the resulting storage of reductant (i.e., ammonia) in the second SCR catalyst.

According to another embodiment, the step of determining the first amount may include the step of estimating the first amount based on a temperature of the exhaust gas entering the first catalyst for selective catalytic reduction, a mass flow rate of the exhaust gas flowing through the first catalyst for selective catalytic reduction, and a Nitrogen oxide content in the exhaust gas upstream of the first catalyst for selective catalytic reduction include.

Thanks to this solution, the first quantity can be determined taking into account the most important parameters that influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the first SCR catalyst.

In another embodiment, the step of determining the second amount may include the step of estimating the second amount based on a nitrogen oxide level in the exhaust upstream of the second selective catalytic reduction catalyst and upstream of the first selective catalytic reduction catalyst and upstream of the amount of reductant in the exhaust from the second catalyst for selective catalytic reduction and upstream of the first catalyst for selective catalytic reduction.

Thanks to this solution, the second quantity can be determined taking into account the most important parameters which influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the second SCR catalyst.

• – Mittel zum Bestimmen einer in einem selektiven katalytischen Reduktionssystem gespeicherten Reduktionsmittelmenge auf Basis einer in einem ersten Katalysator zur selektiven katalytischen Reduktion des selektiven katalytischen Reduktionssystems gespeicherten ersten Reduktionsmittelmenge und einer in einem zweiten Katalysator zur selektiven katalytischen Reduktion des selektiven katalytischen Reduktionssystems gespeicherten zweiten Reduktionsmittelmenge;
• – Mittel zum Bestimmen eines Sollwerts des in dem selektiven katalytischen Reduktionssystem gespeicherten Reduktionsmittels als Funktion eines Temperaturwerts eines im zweiten Katalysator zur selektiven katalytischen Reduktion angeordneten Substrats;
• – Mittel zum Berechnen einer Differenz zwischen der Reduktionsmittelmenge und dem Sollwert;
• – Mittel zum Anpassen einer in das Abgasnachbehandlungssystem eingespritzten Reduktionsmitteldosis auf Basis der berechneten Differenz; und
• – Mittel zum Betätigen des Injektors, um die angepasste Reduktionsmitteldosis einzuspritzen.

Another embodiment of the solution provides an apparatus for controlling an injector for injecting a reducing agent into an exhaust aftertreatment system of an internal combustion engine, comprising:

• - means for determining a quantity of reducing agent stored in a selective catalytic reduction system based on a first amount of reducing agent stored in a first catalyst for selective catalytic reduction of the selective catalytic reduction system and a second quantity of reducing agent stored in a second catalyst for selective catalytic reduction of the selective catalytic reduction system;
• Means for determining a set point of the reducing agent stored in the selective catalytic reduction system as a function of a temperature value of a substrate disposed in the second selective catalytic reduction catalyst;
• - means for calculating a difference between the amount of reducing agent and the desired value;
• - Means for adjusting a injected into the exhaust aftertreatment system reducing agent dose based on the calculated difference; and
• - means for actuating the injector to inject the adjusted reducing agent dose.

Thanks to this solution, it is possible to improve the control of the reducing agent dose injected upstream of the first SCR catalyst of a multicomponent SCR system into the exhaust stream, to maximize the NOx conversion of the SCR system and to pass through the SCR system to the outside Minimize the amount of ammonia released.

In one embodiment, the apparatus may include means for calculating the setpoint as a sum of a first setpoint of the reductant stored in the first selective catalytic reduction catalyst and a product of a second setpoint of the reductant stored in the second selective catalytic reduction catalyst and a multiplier which is at the temperature value of the second Catalyst for selective catalytic reduction arranged substrate based.

Is it possible to control the reductant dose injected upstream of the first SCR catalyst of a multicomponent SCR system into the exhaust stream and to correct it with low calibration overhead and low computational power. In fact, known models of reducing agent dose injected into a one-component SCR system can be readily adapted to control the dose of reducing agent injected into a multi-component SCR system.

According to one embodiment, the apparatus may include means for calculating the amount of reductant as a sum of the first reductant amount and a product of the second reductant amount and a second multiplier based on the temperature value of the substrate disposed in the second selective catalytic reduction catalyst.

Thanks to this solution, it is possible to control the reductant dose injected upstream of the first SCR catalyst into the exhaust stream as a function of the maximum storage capacity of the SCR system at the actual temperature of the SCR catalysts of the SCR system.

According to one embodiment, the first multiplier may be equal to the second multiplier.

Thanks to this solution, the determination of the setpoint can be carried out with low calibration effort and low computing power.

According to another embodiment, the first setpoint determining means may include means for estimating the first setpoint value based on a temperature of a first substrate disposed in the first selective catalytic reduction catalyst and a mass flow rate of the exhaust gas flowing through the first selective catalytic reduction catalyst ,

Thanks to this solution, the first set point can be determined taking into account the most important parameters that influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the first SCR catalyst.

In another embodiment, the second setpoint determining means may include means for estimating the second setpoint value based on a temperature of the substrate disposed in the second selective catalytic reduction catalyst and a mass flow rate of the exhaust gas flowing through the second selective catalytic reduction catalyst.

Thanks to this solution, the second set point can be determined taking into account the most important parameters that influence the NOx conversion and the resulting storage of reductant (i.e., ammonia) in the second SCR catalyst.

According to another embodiment, the means for determining the first amount may include means for determining the first amount based on a temperature of the exhaust gas entering the first selective catalytic reduction catalyst, a mass flow rate of the exhaust gas flowing through the first selective catalytic reduction catalyst, and an exhaust gas Estimate nitrogen oxide content in the exhaust gas upstream of the first catalyst for selective catalytic reduction.

Thanks to this solution, the first quantity can be determined taking into account the most important parameters that influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the first SCR catalyst.

According to another embodiment, the means for determining the second amount may include means for increasing the second amount based on a nitrogen oxide level in the exhaust upstream of the second selective catalytic reduction catalyst and upstream of the first selective catalytic reduction catalyst and upstream of the reducing agent portion from the second catalyst for selective catalytic reduction and upstream of the first catalyst for selective catalytic reduction.

Thanks to this solution, the second quantity can be determined taking into account the most important parameters which influence NOx conversion and the resulting storage of reductant (i.e., ammonia) in the second SCR catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

Now, the various embodiments will be described by way of example with reference to the accompanying drawings, in which:

1 shows a motor vehicle system;

2 a cross-section of a to the motor vehicle system of 1 belonging internal combustion engine;

3 a schematic representation of a to the motor vehicle system of 1 belonging to the SCR system;

4 FIG. 3 is a flowchart illustrating a method of controlling the reductant injector of the SCR system according to one embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Some embodiments may be a motor vehicle system 100 include that in the 1 and 2 is shown and that an internal combustion engine (ICE) 110 with a cylinder block 120 owns at least one cylinder 125 with a piston 140 defined, which has a coupling with which the crankshaft 145 is turned. A cylinder head 130 works with the piston 140 together to a combustion chamber 150 define.

An air-fuel mixture (not shown) enters the combustion chamber 150 introduced and ignited, resulting in hot expanding combustion gases, leading to a reciprocation of the piston 140 to lead. The fuel is from at least one fuel injector 160 provided and the air through at least one inlet 210 , The fuel is under high pressure from a fuel pipe 170 , the fluid zueitend with a high-pressure pump 180 that the pressure of a fuel source 190 increased fuel, is connected to the fuel injector 160 guided. The fuel injection system with the components described above is known as a common-rail diesel (CR) injection system. It is a relatively new injection system for passenger cars. The main advantage of this injection system compared to others is that due to the high pressure in the system and the electromagnetically controlled injectors, it is possible to inject the correct quantities of fuel at just the right time. This leads to lower fuel consumption and lower emissions.

Each of the cylinders 125 has at least two valves 215 coming from a camshaft 135 operated at the same time as the crankshaft 145 rotates. The valves 215 selectively release air from the inlet 210 in the combustion chamber 150 and alternately allow the outlet of the exhaust gases through the outlet 220 , In some examples, a camshaft phasing system 155 used to selectively the timing between the camshaft 135 and the crankshaft 145 to change.

The air can be the air inlets 210 via an intake manifold 200 be supplied. An air inlet pipe 205 leads the intake manifold 200 Ambient air too. In other embodiments, a throttle 330 be selected to control the air flow to the intake manifold 200 to regulate. In other embodiments, a compressed air system such as a turbocharger is used 230 with a compressor 240 that is together with a turbine 250 turns, used. The rotation of the compressor 240 increases the pressure and temperature of the air in the air inlet duct 205 and the intake manifold 200 , One in the air intake pipe 205 containing intercooler 260 can reduce the temperature of the air.

The turbine 250 turns when flowing from an exhaust manifold 225 coming exhaust gases, the exhaust gas from the outlet 220 passes through a series of vanes before passing through the turbine 250 is expanded. The exhaust gases leave the turbine 250 and become an exhaust aftertreatment system 270 This example shows a variable geometry turbine (VGT) 250 with a VGT actuator 255 configured to move the vanes to cause the vanes to flow the exhaust gas through the turbine 250 to change.

The exhaust aftertreatment system 270 can be an exhaust pipe 275 comprising one or more exhaust aftertreatment devices 280 Has. aftertreatment devices 280 may be any devices with which the composition of the exhaust gases can be changed. Some examples of aftertreatment devices 280 include, but are not limited to, catalytic (two- and three-way) converters, oxidation catalysts, for example, a diesel oxidation catalyst (DOC). 281 , a NOx trap for lean operation (LNT), hydrocarbon adsorber or a reducing agent storage device such. B. a selective catalytic reduction system (SCR system).

In the illustrated embodiment, the SCR system is 282 a multicomponent SCR system using a first catalyst for selective catalytic reduction (SCR catalyst) 283 and a second catalyst for selective catalytic reduction (SCR catalyst) 284 includes. The exhaust pipe 275 and for example the DOC 281 provide fluid communication between the exhaust manifold 225 and the first SCR catalyst 283 ago, so that the exhaust pipe 275 through the DOC 281 Exhaust from the ICE 110 to the first SCR catalyst 283 promoted. The exhaust pipe 275 defines a passage that provides fluid communication between the first SCR catalyst 283 and the second SCR catalyst 284 manufactures.

The first SCR catalyst 283 is in the exhaust pipe 275 upstream of the second SCR catalyst 284 arranged.

In the illustrated embodiment, the first SCR catalyst is 283 a direct-coupled catalyst for selective catalytic reduction on a filter (SCRoF), ie a particle filter with an SCR coating.

The second SCR catalyst 284 is an underbody catalyst for selective catalytic reduction (SCR U / F).

The SCR system 282 includes a container 285 for inclusion of a reduction promoter 286 , such as As urea or an aqueous urea solution (urea-water solution HWL), in the container 285 is stored.

A reducing agent injector 287 is designed to be the reduction promoter 286 ie the aqueous urea solution, from the container 285 upstream of the first SCR catalyst 283 in the exhaust pipe 274 to inject.

Due to the high exhaust gas temperatures at this point of the exhaust pipe 275 For example, the aqueous urea solution is thermally decomposed, during which process an actual reducing agent, namely ammonia (NH ₃ ), is liberated.

Especially at temperatures above 160 ° C begins a process in which the urea is subjected to hydrolysis and thermal decomposition, resulting in the formation of ammonia. The resulting mixture of urea / ammonia and exhaust gases then passes to the first SCR catalyst 283 where the ammonia reacts with the NOx gases to form nitrogen and water.

It can be a pump 288 used to be the reduction promoter 286 (ie the aqueous urea solution or urea) from the container 285 to the reducing agent injector 287 to transport. Optionally, treatment agents that promote homogenization and / or degradation of the urea may also be present between the reductant injector 287 and the first SCR catalyst 283 to be available.

The released reductant (ie, ammonia) becomes either in a first catalytic substrate 283 ' of the first SCR catalyst 283 and / or in a second catalytic substrate 284 ' of the second SCR catalyst 284 stored, or it gets here with the nitrogen oxides of the exhaust gases of the ICE 110 directly catalytically reacted, these oxides are then reduced to form nitrogen N ₂ .

The motor vehicle system 100 can still use an electronic control unit (ECM) 450 configured to receive signals from or to various, with the ICE 110 connected sensors and / or devices to send or receive. The ECM 450 It can receive input signals from various sensors designed to generate the signals proportional to various physical parameters associated with the ICE 110 are. The sensors include, but are not limited to, an air mass flow, pressure, and temperature sensor 340 , a pressure and temperature sensor 350 for the manifold, a sensor 360 for the pressure in the combustion chamber, sensors 380 for the coolant and oil temperature and / or the associated fill level, a pressure sensor 400 for the fuel, a camshaft position sensor 410 , a crankshaft position sensor 420 , Sensors 430 for the pressure and the temperature of the exhaust gases, an oxygen sensor, for example, a broad-band probe for oxygen (UEGO) or a lambda probe, or a nitrogen oxide sensor and an accelerator pedal position sensor 445 ,

The sensors also include NOx sensors designed to determine the amount of NOx (nitrogen oxides) in the exhaust, e.g. In parts per million.

For example, a first NOx sensor 440 ' in the exhaust pipe 275 upstream of the first SCR catalyst 283 arranged.

A second NOx sensor 440 '' can in the exhaust pipe 275 for example, downstream from the second SCR catalyst 284 be arranged.

The mass flow rate in the intake manifold 200 flowing air is measured using an air mass meter (MAF) 441 measured.

A first exhaust gas temperature sensor 442 ' is at or near an inlet of the first SCR catalyst 283 arranged, z. B. in the exhaust pipe 275 upstream of the first SCR catalyst 283 ,

The ECM 450 may be designed to be the temperature of the first SCR catalyst 283 arranged first catalytic substrate 283 ' for example, a ceramic-coated substrate made of, for example, a cordierite material and having a plurality of flow passages coated with a primer and catalytic materials to store the reducing agent (ie, ammonia) with those supplied Exhaust gas flow of existing NOx molecules reacts. In particular, the ECM 450 the temperature of the catalytic substrate 283 ' based on the temperature of the first SCR catalyst 283 entering exhaust gas (measured by the first exhaust gas temperature sensor 442 ' ) and the exhaust gas mass flow rate.

A second exhaust gas temperature sensor 442 '' is at or near an inlet of the second SCR catalyst 284 arranged, z. B. in the exhaust pipe 275 upstream of the second SCR catalyst 284 and upstream of the first SCR catalyst 283 ,

The ECM 450 may be designed to be the temperature of the second SCR catalyst 284 arranged second catalytic substrate 284 ' for example, a ceramic-coated substrate made of, for example, a cordierite material and having a plurality of flow passages coated with a primer and catalytic materials to store the reducing agent (ie, ammonia) with those supplied Exhaust gas flow of existing NOx molecules reacts. In particular, the ECM 450 the temperature of the second catalytic substrate 284 ' based on the temperature of the second SCR catalyst 283 entering exhaust gas (measured by the second exhaust gas temperature sensor 442 '' ) and the exhaust gas mass flow rate.

The ECM 450 may be the rate at which the temperature of the first and second catalytic substrate 283 ' . 284 ' is increased in response to a change in the exhaust gas temperature as the exhaust gas mass flow rate increases.

The temperature of each catalyst for selective catalytic reduction (SCR catalyst) 283 . 284 (ie, the first and second catalytic substrates 283 ' . 284 ' ) influences the efficiency of the reactions in the particular SCR catalyst which reduce the nitrogen oxides and also has an effect on the ability of the SCR catalyst to store the reducing agent (ie ammonia). When the temperature of the SCR catalyst is low and z. B. is less than 144 degrees Celsius (° C), the efficiency of the reactions that reduce the nitrogen oxides in the SCR catalyst is close to zero. Therefore, even if the SCR catalyst contains ammonia, the ammonia does not react with the nitrogen oxides and does not reduce them. When the temperature of the SCR catalyst is high, e.g. B. higher than 400 ° C, the SCR catalyst is not able to store ammonia.

The temperature of the SCR catalyst is determined by the distance between the ICE 110 and the SCR catalyst. The distance between the ICE 110 and the first SCR catalyst 283 located immediately downstream of the DOC 281 can be relatively short, ie shorter than the distance between the ICE 110 and the second SCR catalyst 284 ,

If the ICE 110 Initially started, the temperature of the second SCR catalyst 284 therefore, be too low so that the nitrogen oxides are not efficiently reduced, with one passing through the reductant injector 287 dose of reducing promoter to be injected 286 can be determined by the reduced storage capacity of the SCR system 282 Take into account.

On the other hand, if the ICE 110 runs and the temperature of the exhaust gas increases significantly, the temperature of the first SCR catalyst 283 be too high, so that the reducing agent (ie ammonia) is not stored efficiently, which is towards the second SCR catalyst 284 escapes, one through the reductant injector 287 dose of reducing promoter to be injected 286 can be determined by the reduced storage capacity of the SCR system 282 Take into account.

Furthermore, the ECM 450 to output various signals to control the operation of the ICE 110 to control, for example, but not exclusively, to the fuel injectors 160 , to the throttle 330 , to the EGR valve 320 , to the VGT actuator 255 , to the camshaft adjustment system 155 , to the pump 288 and to the reducing agent injector 287 , It should be noted that dashed lines are used to indicate various connections between the various sensors, devices and the ECM 450 but others have been omitted for purposes of clarity.

The control unit 450 For example, a digital microprocessor unit (CPU) connected to a memory system and a bus system 460 ). The CPU is adapted to execute instructions executed as a program stored in the memory system, to capture input signals from the data bus, and to output signals to the data bus. The storage system may have various storage media such as optical, magnetic, solid state and other non-volatile media. The data bus may be configured to send, receive, and modulate analog and / or digital signals to and from the various sensors and control devices. The program may be such that it is capable of embodying the methods described herein so that the CPU may perform the steps of such methods, and thus the ICE 110 can control.

The program stored in the storage system is fed to the control unit from the outside by cable or by radio. Outside the Automotive Systems 100 it regularly appears on a computer program product, also referred to in the art as a computer or machine readable medium, which is to be understood as a computer program code on a carrier. The wearer may be volatile or non-volatile with the result that one can also speak of a volatile or non-volatile nature of the computer program product.

An example of a volatile computer program product is a signal, such as an electromagnetic signal, such as an optical signal, that is a transient carrier for the computer program code. The carrying of the computer program code may be achieved by modulating the signal with a conventional modulation technique such as QPSK for digital data so that binary data representing the computer program code is impressed on the volatile electromagnetic signal. Such signals are used, for example, when a computer program code is wirelessly transmitted to a laptop over a WiFi connection.

In the case of a non-volatile computer program product, the computer program code is embodied in a substrate-bound storage medium. The storage medium is then the non-volatile carrier referred to above, such that the computer program code is permanently or non-permanently stored in or on the storage medium in a retrievable manner. The storage medium may be of the conventional type known in the field of computer technology, for example a flash memory, an asic, a CD and the like.

Instead of an engine control unit 450 can the motor vehicle system 100 have a different type of processor to provide the electronic logic, such as an embedded controller, an on-board computer, or any other type of processor that can be used in a vehicle.

An electronic control unit, ie the ECM 450 , is operative with the reducing agent injector 287 connected to a dose of reduction promoter 286 to be controlled by the reducing agent injector 287 is injected.

In particular, by putting the pressure of the reduction promoter 286 that by the pump 288 to the reducing agent injector 287 and an operating time of the reducing agent injector 287 controls, controls the ECM 450 the dose of reduction promoter 286 that of the reducing agent injector 287 is injected.

The ECM 450 is designed to perform a procedure where the ECM 450 one in the first SCR catalyst 283 stored first amount of reducing agent (ie ammonia) determined (block S1).

The ECM 450 is designed to withstand a mass flow rate of the ICE 110 coming and through the exhaust aftertreatment system 270 to determine flowing exhaust gas (block S2).

For example, the ECM determines 450 an exhaust gas mass flow rate from the ICE 110 based on a mass flow rate in the ICE 110 entering air and a fuel delivery rate to the ICE 110 , For this, the ECM 450 the air mass flow rate from the air mass meter 441 receive. The ECM 450 The fueling rate of a fuel meter can be used to determine the mass flow rate of fuel through the fuel pipe 170 certainly. The exhaust gas mass flow rate may be based on a sum of a mass flow rate into the ICE 110 entering air and a fuel delivery rate to the ICE 110 be based (or equal to this).

The ECM 450 is designed to determine a proportion of nitrogen oxide in the exhaust gas (block S3). The ECM 450 can be the first in the SCR catalyst 283 entering nitrogen oxide content based on an input from the NOx sensor, for example, the first NOx sensor 440 ' , determine.

The ECM 450 appreciates the first SCR catalyst 283 stored first amount of reducing agent (ie ammonia). In particular, the ECM 450 the first amount based on the exhaust mass flow rate (as disclosed above) of the exhaust gas (as disclosed above) into the first SCR catalyst 283 entering nitrogen oxide content and the temperature of the first SCR catalyst 283 estimate incoming exhaust gas. The temperature of the first SCR catalyst 283 Incoming exhaust gas may, for example, by the first exhaust gas temperature sensor 442 ' be estimated (block S4) or otherwise estimated using estimation methods known in the art.

For example, the first set may be provided as an output of a pre-calibrated first model (MO1) that inputs the exhaust mass flow rate into the first SCR catalyst 283 entering nitrogen oxide content and the temperature of the in the first SCR catalyst 283 incoming exhaust gas receives. This first model can be predicted in experiments and stored in the storage system.

The first model gives as outputs one from the first SCR catalyst 283 leaking nitrogen oxide content and a proportion of reducing agent (ie, ammonia) from the first SCR catalyst 283 exit (and towards the second SCR catalyst 284 escapes).

The first model consists of a phenomenological chemical model (multi-layer 1DK model), which takes into account the most important parameters influencing the NOx conversion and the resulting storage of the reducing agent (ie ammonia): space velocity, temperature of the SCR catalyst, NO ₂ / NO _x ratio in the exhaust stream, capacity for storing reductant (ie, ammonia) of the SCR catalyst, etc.

It will be obvious to those skilled in the art how to make this first model by performing the required testing or simulation procedures. To explain this in more detail, however, it will be explained below how this first model can be created.

• • Verändern der Eingaben (d. h. Abgas-Massendurchsatz, in den ersten SCR-Katalysator 283 eintretender Stickoxidanteil und Temperatur des in den ersten SCR-Katalysator 283 eintretenden Abgases) innerhalb eines jeweiligen Betriebsbereichs, der zum Beispiel sämtliche Betriebszustände des Verbrennungsmotors abdeckt; um die Eingaben zu verändern, kann der ICE 110 beispielsweise an unterschiedlichen Betriebspunkten (d. h. mit unterschiedlichen Motordrehzahlen und Motorlasten) betrieben werden, wobei jeder Betriebspunkt beispielsweise während eines vorbestimmten Zeitraums konstant gehalten wird, wie dies dem Fachmann bekannt ist;
• • Verändern der durch den Reduktionsmittelinjektor eingespritzten Menge an Reduktionsmittelpromoter;
• • für eine Vielzahl von Eingaben und eine Vielzahl von eingespritzten Reduktionspromotermengen erfolgendes Messen der entsprechenden Werte des NOx-Anteils und des Anteils an Reduktionsmittel (d. h. Ammoniak) (stromabwärts vom ersten SCR-Katalysator) mithilfe der Sensoren;
• • Schätzen der im ersten SCR-Katalysator gespeicherten ersten Reduktionsmittelmenge zum Beispiel mithilfe eines im ECM 450 enthaltenen virtuellen Sensors, der dafür ausgelegt ist, die Reduktionsmittelkonzentration auf dem beschichteten ersten Substrat des ersten SCR-Katalysators während des laufenden Betriebs des ICE 110 zu schätzen. Der virtuelle Sensor wird erzielt, indem ein algorithmischer Code und eine Vielzahl von Kalibrationsfelder ausgeführt werden, welche die Konzentration des im beschichteten ersten Substrat gespeicherten Reduktionsmittels zeitlich bestimmen, wie dies im Patent Nr. US 8,333,062 offenbart wird; und
• • Speichern der ersten Mengen, der NOx-Anteile und der Anteile an Reduktionsmittel (d. h. Ammoniak) in einem ersten Modell, das jede Vielzahl von Eingaben (und die jeweilige eingespritzte Menge an Reduktionsmittelpromoter) mit jeder Dreiergruppe an Ausgaben (d. h. eine erste Menge, ein NOx-Anteil und ein Anteil an Reduktionsmittel (d. h. Ammoniak)) in Beziehung setzt.

For example, as part of experiments to determine the first model, a technician may perform a calibration procedure with at least one test engine, for example an ICE engine 110 similar and equipped with: an SCR system, the SCR system 282 is similar, and with sensors that are suitable to detect the proportion of reducing agent (ie ammonia) and the NOx content, such. B. with a NOx sensor and / or an FTIR sensor, which is arranged downstream of the first SCR catalyst of the SCR system. This calibration procedure may include the following steps:

• • Changing the inputs (ie, exhaust mass flow rate, into the first SCR catalyst 283 entering nitrogen oxide content and temperature of the first SCR catalyst 283 incoming exhaust gas) within a respective operating range covering, for example, all operating conditions of the internal combustion engine; to change the inputs, the ICE 110 For example, at different operating points (ie, with different engine speeds and engine loads) are operated, each operating point is kept constant, for example, for a predetermined period of time, as is known in the art;
• Changing the amount of reductant promoter injected by the reductant injector;
• For a plurality of inputs and a plurality of injected reduction promoter amounts, measuring the respective values of the NOx fraction and the amount of reductant (ie, ammonia) (downstream of the first SCR catalyst) using the sensors;
• Estimating the first amount of reductant stored in the first SCR catalyst, for example, using one in the ECM 450 contained virtual sensor, which is adapted to the reducing agent concentration on the coated first substrate of the first SCR catalyst during operation of the ICE 110 appreciate. The virtual sensor is achieved by executing an algorithmic code and a plurality of calibration fields that temporally determine the concentration of the reducing agent stored in the coated first substrate, as described in patent no. US 8,333,062 is disclosed; and
• • storing the first quantities, the NOx fractions and the proportions of reducing agent (ie, ammonia) in a first model containing each plurality of inputs (and the respective injected amount of reducing agent promoter) with each triplet of outputs (ie, a first amount NOx content and a proportion of reducing agent (ie ammonia)) is related.

The ECM 450 is designed to be one in the second SCR catalyst 284 stored second amount of reducing agent (ie ammonia) to determine (block S5).

For this, the ECM 450 in the second SCR catalyst 284 estimate stored second amount of reducing agent. In particular, the ECM 450 the second amount, in a manner similar to that disclosed above in relation to the first amount, based on the exhaust mass flow rate (as determined above) of the (as disclosed above) into the second SCR catalyst 284 entering nitrogen oxide content and the temperature of the second SCR catalyst 284 estimate incoming exhaust gas.

Alternatively, the ECM 450 the second quantity based on that from the first SCR catalyst 283 exiting nitrogen oxide fraction (block S6) and from the first SCR catalyst 283 Estimate fraction of reductant (ie, ammonia) (block S7) determined by the first model.

For this, the second set may be provided as an output of a precalibrated second model (block MO2), which inputs from the first SCR catalyst 283 exiting nitrogen oxide content and that from the first SCR catalyst 283 emerging proportion of reducing agent (ie ammonia) receives. This second model can be predetermined in the course of experiments and stored in the storage system.

This second model can consist of a phenomenological chemical model (multi-layer 1DK model).

It will be obvious to those skilled in the art how to construct this second model by performing the required test or simulation operations. To explain this in more detail, however, it will be explained below how this second model can be created.

• • Verändern der Eingaben (d. h. aus dem ersten SCR-Katalysator 283 austretender Stickoxidanteil und aus dem ersten SCR-Katalysator 283 austretenden Anteil an Reduktionsmittel (d. h. Ammoniak)) innerhalb eines jeweiligen Betriebsbereichs, der zum Beispiel sämtliche Betriebszustände des Verbrennungsmotors abdeckt, bei denen ein Entweichen von Reduktionsmittel stromabwärts vom ersten SCR-Katalysator beobachtet wird; um die Eingaben zu verändern, kann der ICE 110 beispielsweise an unterschiedlichen Betriebspunkten (d. h. mit unterschiedlichen Motordrehzahlen und Motorlasten) betrieben werden, wobei jeder Betriebspunkt beispielsweise während eines vorbestimmten Zeitraums konstant gehalten wird, wie dies dem Fachmann bekannt ist;
• • Schätzen der im zweiten SCR-Katalysator gespeicherten zweiten Reduktionsmittelmenge, zum Beispiel mithilfe eines im ECM 450 enthaltenen virtuellen Sensors, der dafür ausgelegt ist, die Reduktionsmittelkonzentration auf dem beschichteten zweiten Substrat des zweiten SCR-Katalysators während des laufenden Betriebs des ICE 110 zu schätzen. Der virtuelle Sensor wird erzielt, indem ein algorithmischer Code und eine Vielzahl von Kalibrationsfelder ausgeführt werden, welche die Konzentration des im beschichteten ersten Substrat gespeicherten Reduktionsmittels zeitlich bestimmen, wie dies im Patent Nr. US 8,333,062 offenbart wird; und
• • Speichern der zweiten Mengen in einem zweiten Modell, das jede Vielzahl von Eingaben (jeden NOx-Anteil und jeden Anteil an Reduktionsmittel (d. h. Ammoniak)) mit jeder Ausgabe (d. h. einer zweiten Menge) in Beziehung setzt.

For example, as part of experiments to determine the second model, a technician may perform a calibration procedure with at least one test engine, for example an ICE engine 110 similar and equipped with an SCR system, which is the SCR system 282 like. This calibration procedure may include the following steps:

• • Modifying the inputs (ie from the first SCR catalyst 283 leaking nitrogen oxide content and from the first SCR catalyst 283 exiting portion of reductant (ie, ammonia) within a respective operating range covering, for example, all operating conditions of the internal combustion engine in which leakage of reductant downstream from the first SCR catalyst is observed; to change the inputs, the ICE 110 For example, at different operating points (ie, with different engine speeds and engine loads) are operated, each operating point is kept constant, for example, for a predetermined period of time, as is known in the art;
• Estimate the second amount of reductant stored in the second SCR catalyst, for example using one in the ECM 450 contained virtual sensor, which is adapted to the reducing agent concentration on the coated second substrate of the second SCR catalyst during the ongoing operation of the ICE 110 appreciate. The virtual sensor is achieved by executing an algorithmic code and a plurality of calibration fields that temporally determine the concentration of the reducing agent stored in the coated first substrate, as described in patent no. US 8,333,062 is disclosed; and
• • Store the second quantities in a second model relating each plurality of inputs (each NOx fraction and each reductant (ie, ammonia)) to each output (ie, a second set).

After the first quantity and the second quantity are known, the ECM 450 determine an amount of reductant (ie, ammonia) (block S8) that is actually in the SCR system 282 ie in the first SCR catalyst 283 and in the second SCR catalyst 284 , is stored.

The actual amount represents the amount of reducing agent (ie ammonia) present in the SCR system 282 actually reduced nitrogen oxides.

An actual amount of ammonia stored in the SCR catalysts becomes a function of the first amount and the second amount as well as the temperature of the second SCR catalyst 284 calculated (block S9), for example by the second exhaust gas temperature sensor 442 '' is measured.

This is done based on the temperature of the second SCR catalyst 284 a first multiplier determined.

The values of the first multiplier may be dependent on the temperature of the second SCR catalyst 284 between 0 and 1.

The actual amount of ammonia stored in the SCR catalysts is determined as the sum of the first amount and a product of the first multiplier and the second amount.

The first multiplier may be provided as an output of a pre-calibrated first map that inputs the temperature of the second SCR catalyst 284 receives. This first map can be predetermined in the context of experiments and stored in the storage system.

• • Verändern der Temperatur des zweiten SCR-Katalysators innerhalb eines jeweiligen Betriebsbereichs, der zum Beispiel sämtliche Betriebszustände des Verbrennungsmotors abdeckt;
• • Schätzen der im SCR-System gespeicherten tatsächlichen Reduktionsmittelmenge zum Beispiel mithilfe eines im ECM 450 enthaltenen virtuellen Sensors, der dafür ausgelegt ist, die Reduktionsmittelkonzentration auf den beschichteten Substraten des SCR-Systems während des laufenden Betriebs des ICE 110 zu schätzen. Der virtuelle Sensor wird erzielt, indem ein algorithmischer Code und eine Vielzahl von Kalibrationsfelder ausgeführt werden, welche die Konzentration des in den beschichteten Substraten gespeicherten Reduktionsmittels zeitlich bestimmen, wie dies im Patent Nr. US 8,333,062 offenbart wird; und
• • Berechnen einer Differenz zwischen jeder geschätzten tatsächlichen Menge und jeder ersten Menge;
• • Berechnen jedes ersten Multiplikators als Verhältnis zwischen der Differenz und jeder jeweiligen zweiten Menge; und
• • Speichern des ersten Multiplikators in einem ersten Kennfeld, das jede Vielzahl von Eingabepaaren mit einem jeweiligen ersten Multiplikator in Beziehung setzt.

For example, as part of experiments to determine the first map, a technician may perform a calibration procedure with at least one test engine, such as an ICE engine 110 similar and equipped with an SCR system, which is the SCR system 282 like. This calibration procedure may include the following steps:

• • changing the temperature of the second SCR catalyst within a respective operating range covering, for example, all operating conditions of the internal combustion engine;
• • Estimate the actual amount of reductant stored in the SCR system using, for example, one in the ECM 450 contained virtual sensor, which is adapted to the reducing agent concentration on the coated substrates of the SCR system during operation of the ICE 110 appreciate. The virtual sensor is achieved by performing an algorithmic code and a plurality of calibration fields that time the concentration of the reducing agent stored in the coated substrates, as described in patent no. US 8,333,062 is disclosed; and
• Calculating a difference between each estimated actual amount and each first quantity;
• Calculating each first multiplier as the ratio between the difference and each respective second set; and
• • storing the first multiplier in a first map relating each plurality of input pairs to a respective first multiplier.

The estimate of the SCR catalysts in the SCR system 282 The amount of reducing agent (ie, ammonia) stored based on the temperature of the exhaust gas flowing through the SCR catalysts ensures that the SCR catalyst's ability to store reductant (ie, ammonia) at high temperatures is accommodated. The estimate of the SCR catalysts in the SCR system 282 stored actual amount of reducing agent (ie, ammonia) using the first multiplier ensures that the decreasing reaction efficiency (and / or reducing agent storage capacity) of the second SCR catalyst 284 at low temperatures.

If more than one other SCR catalyst is downstream of the second SCR catalyst 284 may be applied, a first multiplier may be applied to the estimated further amount of reducing agent stored in each further SCR catalyst downstream of the second SCR catalyst 284 is arranged.

The ECM 450 is also designed to set a first setpoint in the first SCR catalyst 283 to determine the stored first amount of reducing agent (block S10).

The ECM 450 estimates the first setpoint. In particular, the ECM 450 the first setpoint based on the exhaust mass flow rate (as disclosed above) and the temperature of the first SCR catalyst 283 incoming exhaust gas measured, for example, as disclosed above (eg, by the first exhaust temperature sensor 442 ' ).

For example, the first setpoint may be provided as an output of a pre-calibrated third model (block MO3), which inputs the exhaust mass flow rate and the temperature of the first SCR catalyst 283 incoming exhaust gas receives. This third model can be predetermined in the course of experiments and stored in the storage system.

To fill this third model, it is necessary for each operating point of the first SCR catalyst 283 (ie temperature of the first SCR catalyst 283 incoming exhaust gas and / or temperature of the first catalytic substrate 283 ' and space velocity, ie mass flow rate of the into the first SCR catalyst 283 incoming exhaust gas) the maximum storage capacity of the first SCR catalyst 283 to determine.

It will be apparent to those skilled in the art how to construct this third model by performing the required test or simulation operations. To explain this in more detail, however, it will be explained below how this third model can be created.

• • für jeden Abgas-Massendurchsatz und jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases innerhalb eines jeweiligen Betriebsbereichs, der zum Beispiel sämtliche Betriebszustände des Verbrennungsmotors abdeckt, erfolgendes Verändern der eingespritzten Reduktionspromoterdosis, indem der Reduktionsmittelinjektors entsprechend betätigt wird; um den Abgas-Massendurchsatz und die Temperatur des in den ersten SCR-Katalysator eintretenden Abgases zu verändern, kann der Verbrennungsmotor beispielsweise an unterschiedlichen Betriebspunkten (d. h. mit unterschiedlichen Motordrehzahlen und Motorlasten) betrieben werden, wobei jeder Betriebspunkt beispielsweise während eines vorbestimmten Zeitraums konstant gehalten wird, wie dies dem Fachmann bekannt ist;
• • für jeden Abgas-Massendurchsatz und jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases erfolgendes Messen des Anteils an Reduktionsmittel (d. h. Ammoniak) stromabwärts vom ersten SCR-Katalysator, bis der gemessene Anteil an Reduktionsmittel (d. h. Ammoniak) einen vorbestimmten Schwellenwert übersteigt, der zum Beispiel zwischen 0 und 10 ppm beträgt;
• • für jeden Abgas-Massendurchsatz und jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases erfolgendes Setzen des gemessen Anteils an Reduktionsmittel (d. h. Ammoniak), welcher der zuletzt eingespritzten Reduktionspromoterdosis entspricht, bei welcher der gemessene Anteil an Reduktionsmittel (d. h. Ammoniak) niedriger als der vorbestimmte Schwellenwert ist, als ersten Sollwert;
• • Speichern jedes ersten Sollwerts in einem dritten Modell, das jede Vielzahl von Eingaben (jeden Abgas-Massendurchsatz und jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases) mit jeder Ausgabe (jedem ersten Sollwert) in Beziehung setzt.

For example, as part of experiments to determine the third model, a technician may perform a calibration procedure with at least one test engine, for example an ICE engine 110 and equipped with: an SCR system comprising a first SCR catalyst and sensors suitable for detecting the proportion of reducing agent (ie ammonia), such as e.g. B. with a NOx sensor and / or an FTIR sensor downstream of the first SCR catalyst (the first SCR catalyst 283 is similar) of the SCR system is arranged. This calibration procedure may include the following steps:

• For each exhaust mass flow rate and temperature of the exhaust gas entering the first SCR catalyst within a respective operating range covering, for example, all operating conditions of the internal combustion engine, modifying the injected reduction promoter dose by actuating the reductant injector accordingly; For example, in order to vary the exhaust gas mass flow rate and the temperature of the exhaust gas entering the first SCR catalyst, the engine may be operated at different operating points (ie, at different engine speeds and engine loads), each operating point being kept constant for a predetermined period of time, for example. as is known in the art;
• For each exhaust mass flow rate and temperature of the exhaust gas entering the first SCR catalyst, measuring the amount of reductant (ie, ammonia) downstream of the first SCR catalyst until the measured amount of reductant (ie, ammonia) exceeds a predetermined threshold, for example, between 0 and 10 ppm;
• For each exhaust gas mass flow rate and each temperature of the exhaust gas entering the first SCR catalyst, setting the measured proportion of reducing agent (ie Ammonia) corresponding to the last injected reduction promoter dose at which the measured level of reductant (ie, ammonia) is less than the predetermined threshold as the first set point;
• • Store each first setpoint in a third model relating each plurality of inputs (each exhaust mass flow rate and each temperature of the exhaust gas entering the first SCR catalyst) to each output (each first setpoint).

The ECM 450 is also designed to set a second setpoint in the second SCR catalyst 284 to determine stored second amount of reducing agent (block S11).

The ECM 450 estimates the second setpoint. In particular, the ECM 450 the second setpoint based on exhaust mass flow rate and the temperature of the second SCR catalyst 284 of incoming exhaust gas measured, for example, as disclosed above (eg, by the second exhaust temperature sensor 442 '' ).

The mass flow rate of the second SCR catalyst 284 entering exhaust gas, the mass flow rate of the from the first SCR catalyst 283 and may be estimated based on the exhaust mass flow rate (as disclosed above). For example, the mass flow rate of the second SCR catalyst 284 entering exhaust gas equal to the exhaust mass flow rate (as disclosed above).

For example, the second set point may be provided as an output of a pre-calibrated fourth model (block MO4) which inputs the exhaust gas mass flow rate and the temperature of the second SCR catalyst as input 284 incoming exhaust gas receives. This fourth model can be predicted in the course of experiments and stored in the memory system.

To fill this fourth model, it is necessary for each operating point of the second SCR catalyst 284 (ie temperature of the second SCR catalyst 284 incoming exhaust gas and / or temperature of its second catalytic substrate 284 ' and space velocity, ie, mass flow rate of the second SCR catalyst 284 incoming exhaust gas) the maximum storage capacity of the second SCR catalyst 284 to determine.

It will be obvious to those skilled in the art how to make this fourth model by performing the required testing or simulation procedures. To explain this in more detail, however, it will be explained below how this first model can be created.

• • für jeden Abgas-Massendurchsatz und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases innerhalb eines jeweiligen Betriebsbereichs, der zum Beispiel sämtliche Betriebszustände des Verbrennungsmotors abdeckt, erfolgendes Verändern der eingespritzten Reduktionspromoterdosis, indem der Reduktionsmittelinjektor entsprechend betätigt wird;
• • für jeden Abgas-Massendurchsatz und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases erfolgendes Messen des Anteils an Reduktionsmittel (d. h. Ammoniak) stromabwärts vom zweiten SCR-Katalysator, bis der gemessen Anteil an Reduktionsmittel (d. h. Ammoniak) einen vorbestimmten Schwellenwert übersteigt, der zum Beispiel zwischen 0 und 10 ppm beträgt;
• • für jeden Abgas-Massendurchsatz und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases erfolgendes Setzen des gemessen Anteils an Reduktionsmittel (d. h. Ammoniak), welcher der zuletzt eingespritzten Reduktionspromoterdosis entspricht, bei welcher der gemessene Anteil an Reduktionsmittel (d. h. Ammoniak) niedriger als der vorbestimmte Schwellenwert ist, als zweiten Sollwert;
• • Speichern jedes zweiten Sollwerts in einem vierten Modell, das jede Vielzahl von Eingaben (jeden Abgas-Massendurchsatz und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases) mit jeder Ausgabe (jedem ersten Sollwert) in Beziehung setzt.

For example, as part of experiments to determine the fourth model, a technician may perform a calibration procedure with at least one test engine, for example an ICE engine 110 and equipped with: an SCR system comprising a second SCR catalyst (the second SCR catalyst 284 similar, and with a sensor which is capable of detecting the proportion of reducing agent (ie ammonia), such. B. with a NOx sensor and / or an FTIR sensor, which is arranged downstream of the second SCR catalyst of the SCR system. This calibration procedure may include the following steps:

• For each exhaust mass flow rate and temperature of the exhaust gas entering the second SCR catalyst within a respective operating range covering, for example, all operating conditions of the internal combustion engine, modifying the injected reduction promoter dose by actuating the reductant injector accordingly;
• For each exhaust gas mass flow rate and temperature of the exhaust gas entering the second SCR catalyst, measuring the proportion of reductant (ie, ammonia) downstream of the second SCR catalyst until the measured amount of reductant (ie, ammonia) exceeds a predetermined threshold, for example, between 0 and 10 ppm;
• For each exhaust mass flow rate and temperature of the exhaust gas entering the second SCR catalyst, setting the measured amount of reductant (ie, ammonia) corresponding to the last injected reduction promoter dose at which the measured level of reductant (ie, ammonia) is less than the predetermined threshold is as a second setpoint value;
• • Store each second setpoint in a fourth model relating each plurality of inputs (each exhaust mass flow rate and each temperature of the exhaust gas entering the second SCR catalyst) to each output (each first setpoint).

After this first setpoint and second setpoint are known, the ECM 450 determine an actual setpoint for the actual amount of reductant (ie ammonia) (block S12) present in the SCR system 282 ie in the first SCR catalyst 283 and in the second SCR catalyst 284 , is stored.

The actual setpoint becomes a function of the first setpoint, the second setpoint, and the temperature of the second SCR catalyst 284 calculated (block S13), for example by the second exhaust gas temperature sensor 442 '' is measured.

This is done based on the temperature of the second SCR catalyst 284 a second multiplier determined.

The values of the second multiplier may be dependent on the temperature of the second SCR catalyst 284 between 0 and 1.

The actual setpoint is determined as the sum of the first setpoint and a product of the second multiplier and the second setpoint.

The second multiplier may be equal to the first multiplier.

Alternatively, the second multiplier may be provided as an output of a pre-calibrated second map that inputs the temperature of the second SCR catalyst 284 receives. This second map can be predetermined in the context of experiments and stored in the storage system.

• • für jeden Abgas-Massendurchsatz, jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases innerhalb eines jeweiligen Betriebsbereichs, der zum Beispiel sämtliche Betriebszustände des Verbrennungsmotors abdeckt, erfolgendes Verändern der eingespritzten Reduktionspromoterdosis, indem der Reduktionsmittelinjektor entsprechend betätigt wird;
• • für jeden Abgas-Massendurchsatz, jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases erfolgendes Messen des Anteils an Reduktionsmittel (d. h. Ammoniak) stromabwärts vom zweiten SCR-Katalysator, bis der gemessen Anteil an Reduktionsmittel (d. h. Ammoniak) einen vorbestimmten Schwellenwert übersteigt, der zum Beispiel zwischen 0 und 10 ppm beträgt;
• • für jeden Abgas-Massendurchsatz, jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases erfolgendes Setzen des gemessen Anteils an Reduktionsmittel (d. h. Ammoniak), welcher der zuletzt eingespritzten Reduktionspromoterdosis entspricht, bei welcher der gemessene Anteil an Reduktionsmittel (d. h. Ammoniak) niedriger als der vorbestimmte Schwellenwert ist, als tatsächlichen Sollwert;
• • für jeden Abgas-Massendurchsatz, jede Temperatur des in den ersten SCR-Katalysator eintretenden Abgases und jede Temperatur des in den zweiten SCR-Katalysator eintretenden Abgases erfolgendes Berechnen einer Differenz zwischen jedem tatsächlichen Sollwert und jedem entsprechenden ersten Sollwert;
• • Berechnen jedes zweiten Multiplikators als Verhältnis zwischen jeder Differenz und jedem jeweiligen zweiten Sollwert; und
• • Speichern des zweiten Multiplikators in einem zweiten Kennfeld, das jede Vielzahl von Eingaben mit einem jeweiligen ersten Multiplikator in Beziehung setzt.

For example, as part of experiments to determine the second map, a technician may perform a calibration procedure with at least one test engine, for example an ICE engine 110 similar and equipped with: an SCR system, the SCR system 282 is similar, and a sensor which is capable of detecting the proportion of reducing agent (ie ammonia), such. B. with a NOx sensor and / or an FTIR sensor, which is arranged downstream of the second SCR catalyst of the SCR system. This calibration procedure may include the following steps:

• For each exhaust gas mass flow rate, each temperature of the exhaust gas entering the first SCR catalyst, and each temperature of the exhaust gas entering the second SCR catalyst within a respective operating range covering, for example, all operating conditions of the internal combustion engine, modifying the injected reduction promoter dose; by actuating the reductant injector accordingly;
• For each exhaust gas mass flow rate, each temperature of the exhaust gas entering the first SCR catalyst and each temperature of the exhaust gas entering the second SCR catalyst, measuring the amount of reductant (ie ammonia) downstream of the second SCR catalyst until measured Proportion of reducing agent (ie ammonia) exceeds a predetermined threshold, for example between 0 and 10 ppm;
• For each exhaust gas mass flow rate, each temperature of the exhaust gas entering the first SCR catalyst and each temperature of the exhaust gas entering the second SCR catalyst, setting the measured amount of reductant (ie, ammonia) corresponding to the last injected reduction promoter dose wherein the measured proportion of reducing agent (ie, ammonia) is lower than the predetermined threshold, as the actual target value;
• Calculating, for each exhaust gas mass flow rate, each temperature of the exhaust gas entering the first SCR catalyst, and each temperature of the exhaust gas entering the second SCR catalyst, a difference between each actual setpoint and each corresponding first setpoint value;
• Calculating each second multiplier as the ratio between each difference and each respective second setpoint; and
• • storing the second multiplier in a second map relating each plurality of inputs to a respective first multiplier.

The ECM 450 is designed to work in the SCR system 282 stored actual amount of reducing agent (ie ammonia) and the actual set point for controlling the reducing agent injector 287 to use (block S14), in particular by the reducing agent injector 287 injected dose of reduction promoter 286 to control.

This is the ECM 450 designed to calculate a difference between the actual setpoint and the actual amount of reductant and that through the reductant injector 287 injected dose of reduction promoter 286 (ie, aqueous urea solution) to minimize the difference.

If, for example, in the SCR system 282 stored actual amount of reducing agent (ie, ammonia) is less than the actual set point, causes the ECM 450 the reducing agent injector 287 , an additional dose of reduction promoter 286 in the exhaust aftertreatment system 270 upstream of the first SCR catalyst 283 inject the value of the additional dose of reduction promoter 286 based on the difference between the actual setpoint and the actual amount of reducing agent.

For example, the additional dose of reduction promoter 286 be calculated such that by the value of the additional dose of reduction promoter 286 a (stoichiometric) amount of reducing agent, ie ammonia, is released, which is equal to the difference.

If the actual amount of reductant (ie, ammonia) is greater than or equal to the actual set point, the ECM will cause it 450 the reducing agent injector 287 not to an additional dose of reduction promoter 286 in the exhaust aftertreatment system 270 inject.

In the foregoing summary and detailed description, at least one exemplary embodiment has been presented; however, it should be noted that there are a large number of modification options. It should also be noted that the exemplary embodiment or exemplary embodiments are only examples and are not intended to limit the scope, applicability, or construction in any way whatsoever. Rather, the foregoing summary and detailed description will provide those skilled in the art with a practical guide to implementing at least one example embodiment, it being understood that various changes may be made in the functions and arrangements of the elements described with reference to an exemplary embodiment without departing from the spirit of the invention Scope of protection as defined in the appended claims and their legal equivalents.

LIST OF REFERENCE NUMBERS

100

Automotive system

110

internal combustion engine

120

cylinder block

125

cylinder

130

cylinder head

135

camshaft

140

piston

145

crankshaft

150

combustion chamber

155

Cam Phaser System

160

fuel injector

170

Fuel pipe

180

Fuel pump

190

Fuel source

200

intake manifold

205

Air inlet line

210

inlet

215

valves

220

outlet

225

exhaust manifold

230

turbocharger

240

compressor

250

turbine

255

VGT actuator

260

Intercooler

270

aftertreatment system

275

exhaust pipe

280

aftertreatment devices

281

Diesel Oxidation Catalyst (DOC)

282

SCR system

283

first SCR catalyst

283 '

first catalytic substrate

284

second SCR catalyst

284 '

second catalytic substrate

285

container

286

reduction promoter

287

reductant

288

pump

300

Exhaust gas recirculation line

310

EGR cooler

320

EGR valve

330

throttle

340

Mass flow, pressure and temperature sensor for the air

350

Sensor for manifold pressure and temperature

360

Combustion pressure sensor

380

Sensors for coolant temperature and the associated level

385

Sensors for oil temperature and the associated level

400

digital fuel rail pressure sensor

410

Camshaft position sensor

420

Crankshaft position sensor

430

Sensors for pressure and temperature of the exhaust gases

440 '

first NOx sensor

440 ''

second NOx sensor

441

Air flow sensor

442 '

first exhaust gas temperature sensor

442 ''

second exhaust gas temperature sensor

445

Accelerator position sensor

450

electronic control unit (ECM) / controller

460

microprocessor unit

S1-S14

blocks

MO1-MO4

models

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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 assumes no liability for any errors or omissions.

Cited patent literature

• US 8333062 [0110, 0117, 0125]

Claims (10)

Computer program for controlling an injector ( 287 ) for injecting a reducing agent ( 286 ) in an exhaust aftertreatment system ( 270 ) of an internal combustion engine ( 110 ) comprising a program code which, when executed on a computer, performs the following steps: - determining one in a selective catalytic reduction system ( 282 ) based on a in a first catalyst for selective catalytic reduction ( 283 ) of the selective catalytic reduction system ( 282 ) and one in a second catalyst for selective catalytic reduction ( 284 ) of the selective catalytic reduction system ( 282 ) stored second amount of reducing agent; Determining a desired value of the in the selective catalytic reduction system ( 282 ) as a function of a temperature value of one in the second catalyst for selective catalytic reduction ( 284 ) arranged substrate ( 284 ' ); Calculating a difference between the amount of reducing agent and the desired value; - adapting one in the exhaust aftertreatment system ( 270 ) injected reducing agent dose based on the calculated difference; and - actuating the injector ( 287 ) to adjust the adjusted dose of reducing agent ( 286 ). A computer program according to claim 1, wherein the setpoint value is the sum of a first setpoint value of the first catalyst for selective catalytic reduction ( 283 ) and a product from a second desired value of the second catalyst for selective catalytic reduction ( 284 ) and a multiplier which is based on the temperature value of the second catalyst for selective catalytic reduction ( 284 ) arranged substrate ( 284 ' ). The computer program of claims 1 or 2, wherein the amount of reductant is calculated as the sum of the first reductant amount and a product of the second reductant amount and a second multiplier based on the temperature value of the second catalyst for selective catalytic reduction ( 284 ) arranged substrate ( 284 ' ). The computer program of claims 2 and 3, wherein the first multiplier is equal to the second multiplier. The computer program of any one of the preceding claims, wherein the step of determining the first setpoint includes the step of estimating the first setpoint based on a temperature of the first selective catalytic reduction catalyst (16). 283 ) arranged first substrate ( 283 ' ) and a mass flow rate through the first catalyst for selective catalytic reduction ( 283 ) flowing exhaust gas. A computer program according to any one of the preceding claims, wherein the step of determining the second setpoint comprises the step of estimating the second setpoint based on a temperature of the second selective catalytic reduction catalyst (16). 284 ) arranged substrate ( 284 ' ) and a mass flow rate through the second catalyst for selective catalytic reduction ( 284 ) flowing exhaust gas. The computer program of any one of the preceding claims, wherein the step of determining the first set comprises the step of estimating the first set based on a temperature of the first selective catalytic reduction catalyst ( 283 ), a mass flow rate through the first catalyst for selective catalytic reduction ( 283 ) and a nitrogen oxide content in the exhaust gas upstream of the first catalyst for selective catalytic reduction ( 283 ). A computer program according to any one of the preceding claims, wherein the step of determining the second amount comprises the step of estimating the second amount based on a level of nitrogen oxide in the exhaust gas upstream of the second selective catalytic reduction catalyst ( 284 ) and upstream of the first catalyst for selective catalytic reduction ( 284 ) and a reducing agent portion in the exhaust gas upstream of the second selective catalytic reduction catalyst and upstream of the first selective catalytic reduction catalyst ( 284 ). Internal combustion engine ( 110 ), comprising: - an exhaust aftertreatment system ( 270 ) comprising a selective catalytic reduction system ( 282 ) with a first catalyst for selective catalytic reduction ( 283 ) and a second catalyst for selective catalytic reduction ( 284 ) in fluid communication with the first catalyst for selective catalytic reduction ( 283 ) and located downstream thereof, and an injector ( 287 ) which is in fluid communication with a reducing agent ( 286 ) and is designed to deliver a reducing agent dose upstream of the first catalyst for selective catalytic reduction ( 283 ) into the exhaust aftertreatment system ( 270 ) to inject; A control device designed to: one in the selective catalytic reduction system ( 282 ) stored amount of reducing agent based on a first catalyst for selective catalytic reduction ( 283 ) and one in the second catalyst for selective catalytic reduction ( 284 ) to determine the second amount of reducing agent stored; A set point of the in the selective catalytic reduction system ( 282 ) as a function of a temperature value of one in the second catalyst for selective catalytic reduction ( 284 ) arranged substrate ( 284 ' ) to determine; To calculate a difference between the amount of reducing agent and the desired value; - in the exhaust aftertreatment system ( 270 ) injected dose of reducing agent ( 286 ) to adjust based on the calculated difference; and - the injector ( 287 ) to adjust the adjusted dose of reducing agent ( 286 ). Motor vehicle system equipped with an internal combustion engine ( 110 ) is equipped according to claim 9.

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