DE102015220876A1 - Device for controlling an internal combustion engine - Google Patents

Abstract

The invention relates to a device (1) for controlling an internal combustion engine (10) which comprises at least one cylinder (11) with an inlet valve (16) and an outlet valve (17) and which is followed by at least one exhaust aftertreatment catalyst (23) the device (1) comprises a control unit (30). In order to improve the warming up behavior of a catalytic converter in the exhaust system of an internal combustion engine, it is provided according to the invention that the control unit (30) is set up to detect a subconditioning of the catalytic converter (23) and at least one at the same time a subcooling and a fuel cutoff are present Close valve (16, 17) of each cylinder (11) and keep it closed.

Description

The invention relates to a device for controlling an internal combustion engine having the features of the preamble of claim 1.

The exhaust systems of modern internal combustion engines, especially in motor vehicles, are usually provided with various facilities for exhaust aftertreatment. In addition to particulate filters, these include in particular catalysts which favor various chemical reactions by means of which harmful exhaust gas components such as nitrogen oxides, carbon monoxide, etc. are degraded. In general, however, the effect of such catalysts is temperature dependent, with catalysts being virtually inactive at ambient temperature. A measurable activity begins only at a certain temperature, which can be referred to as the activation temperature of the catalyst. However, this depends on the type of catalyst, but is typically well above 100 ° C. It follows that the catalyst is initially inactive for a certain time after a cold start of the associated engine until it is sufficiently warmed up by hot exhaust gases of the engine. A similar warm-up behavior also shows other exhaust aftertreatment systems, ie exhaust systems, eg. Exhaust gas storage systems, particulate filters or catalytic particulate filter, which allow certain chemical reactions at certain temperatures - and possibly with the addition of additives.

Furthermore, in modern vehicle engines also a fuel cut is used, d. H. the controlled interruption of fuel supply to the engine when the accelerator pedal is not operated and the engine speed is above a certain value. This means that the engine continues to run, but no longer drives the vehicle. Rather, the vehicle is pushed into this operating state, with the internal combustion engine acting as a brake. Since no fuel is supplied, sucked in ambient air passes through the engine without combustion process and is heated here at best (by contact with the engine and possibly by compression processes) slightly. This relatively cool air passes in the further course through the exhaust system to the catalyst or to the catalysts and / or other exhaust aftertreatment systems or exhaust system and causes a cooling of the same or hinders heating considerably. The fuel cut thus reduces especially after a cold start the efficiency of the exhaust system, ie z. As the catalyst, resulting in an increased environmental impact of non-catalytically treated exhaust gases.

The JP 2004-169646 A describes a diesel engine in which the intake valves and / or the exhaust valves are closed when a fuel cut occurs. This is to prevent oxygen-rich air from reaching the region of a catalyst located in the exhaust gas line, which could lead to damage at high temperatures of the catalytic converter. In this context, on the one hand there is the danger that an exhaust valve is closed when just an ignition has occurred, so that a return flow takes place in the inlet pipe. On the other hand, if in addition the inlet valve is closed, a high pressure in the cylinder could arise, which can lead to damages. To solve these problems, it is proposed to first expel the combustion gases through the exhaust pipe before the exhaust valve is closed. In this case, in addition, the inlet valve can be fired.

The JP 2009-121433 A shows a turbocharged diesel engine, wherein an intake passage and an exhaust passage of the engine are connected via a return line. In the case of a fuel cut, it is provided that an increased exhaust gas recirculation takes place. To make this process more efficient, a series of rotatable flaps are provided on the turbine side of the turbocharger, through which a passage opening to the turbine can be opened more or less wide. If a fuel cut-off occurs, the port is reduced, increasing the pressure in the upstream portion of the exhaust duct and enhancing the recirculation process. As a result, the exhaust gas cools less, and cooling of a downstream in the exhaust duct catalyst is delayed.

The EP 2 792 865 A1 discloses a method for exhaust gas purification in a diesel engine. Here, a storage catalytic converter is arranged in an exhaust pipe, which is alternately operated in a known manner in lean and rich atmosphere. In order to keep the engine power high and the fuel consumption high in a rich atmosphere, it is provided that a supply air line is closed and a return line is opened if the temperature of the catalyst is above a certain minimum temperature and slows the vehicle above a certain speed. Subsequently, a throttle located downstream of the catalyst is closed and the catalyst is supplied with reducing agent. A closing of the intake or exhaust valves of the engine is not provided.

In view of the cited prior art, the optimization of the warm-up behavior of an exhaust aftertreatment system, ie z. As a catalyst, in particular in view of the above problems in connection with an interruption of fuel supply, still room for improvement.

The invention is therefore based on the object, the warm-up of an exhaust aftertreatment system, ie z. As a catalyst in the exhaust system of an internal combustion engine to improve.

According to the invention the object is achieved by a device having the features of claim 1, wherein the dependent claims relate to advantageous embodiments of the invention.

It should be noted that the features listed in the following description as well as measures in any technically meaningful way can be combined with each other and show other embodiments of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures.

The invention provides a device for controlling an internal combustion engine. The internal combustion engine comprises at least one cylinder with an inlet valve and an outlet valve. Of course, in the (rule) case of several cylinders, this means that each cylinder has at least one inlet valve and at least one outlet valve. Of course, a plurality of intake valves and exhaust valves may be provided. In particular, it may be an internal combustion engine of a motor vehicle, for example a car or truck. The internal combustion engine may, for example, be a diesel engine or a gasoline engine. The internal combustion engine is an exhaust aftertreatment system, ie z. B. downstream of a catalyst for exhaust aftertreatment. In the following, the exhaust aftertreatment system is referred to as a catalyst, of course, for example, exhaust gas storage systems, particulate filter and / or catalytic particulate filter should be included. Of course, several exhaust aftertreatment systems in the flow direction of the exhaust gases sequentially or if necessary. be arranged parallel to each other in the exhaust line. The catalyst is thus arranged downstream of the internal combustion engine. If it is an exhaust gas recirculation (EGR) internal combustion engine, the catalyst may also be located in an exhaust gas recirculation line. The catalyst is of course part of an exhaust system of the internal combustion engine, wherein any existing EGR line is also understood as part of the exhaust system. In principle, this may be any type of catalyst which is suitable for the exhaust aftertreatment of internal combustion engines, for example an oxidation or reduction catalyst. Of course, several catalysts can be provided.

The device comprises a control unit. This can be implemented in terms of hardware and / or software and be embodied physically in one or more parts. In particular, the control unit may be part of a motor control or integrated into it. In a typical embodiment, the engine control of a motor vehicle functions as a control unit.

According to the invention, the control unit is set up to detect a sub-tempering of the catalytic converter, and to close at least one valve of each cylinder and to keep it closed at the same time as a sub-tempering and a fuel cut-off. D. h., The simultaneous presence of Untertemperierung and fuel cut is the condition for closing the valve or the valves. Of course, the control unit is set up to open at least one valve again as soon as either no undertemperature control or no fuel cutoff is present. Here, "supercooling" denotes a state in which the temperature of the catalyst is below a temperature range considered optimal. In particular, the temperature can be so low that the catalyst is not active or does not work efficiently. As will become clear in the following description, it is not absolutely necessary for this that the temperature of the catalyst itself be measured. Rather, it can also be concluded indirectly on the temperature of the catalyst, which in principle can remain a certain margin for error, so that the control unit may incorrectly detects in individual cases a Untertemperierung or incorrectly does not recognize. Thus, "detecting" a sub-tempering in this context means that the state of the catalyst is rated as under temperature. "Fuel cut" here refers to the controlled interruption of the fuel supply to the engine. If necessary, the fuel cut-off can be triggered by the control unit itself.

If the control unit detects a sub-tempering or if it evaluates the condition of the catalyst as under-tempered and at the same time exists a fuel cut, the control unit closes at least one valve (intake valve and / or exhaust valve) of each cylinder (if the respective valve is not already closed) and holds it closed. Thus, no outside air can pass on the way through the cylinder in the exhaust system and the catalyst. That is, the catalyst can not significantly cool down in fuel cutoff periods, or it may even continue to warm up if hot combustion gases from a period prior to overrun fuel cutoff remain in the region of the catalyst. This can be ensured be that the catalyst leaves the state of the lower temperature control much faster compared to the prior art. In other words, in the case of a Untertemperierung is ensured by the control unit that the catalyst is heated normally during fuel supply to the engine, but undergoes no significant cooling when interrupting the fuel supply. The closing of the valves can in this case possibly take place with a certain delay after detecting the Untertemperierung and the onset of fuel cut. It is also conceivable that the valves of different cylinders are not closed at the same time, but at a time interval from each other. Since the phases of the sub-tempering are reduced or minimized by the device according to the invention, the catalyst operates with improved efficiency and the emission of harmful exhaust gases is reduced.

Since the primary object of the invention is to prevent relatively cool air, which has been heated only insignificantly within the engine during an overrun fuel cutoff, from reaching the region of the catalytic converter, it is in principle sufficient for one of the valves of each cylinder to be closed. However, as the pistons continue to operate within the cylinders, this may result in undesirable gas movement upstream or downstream of the cylinders. For example. Exhaust gases could be forced back into the air supply via an open inlet valve, which leads to charge cycle losses. To avoid such effects, the control unit is preferably configured to close both valves of each cylinder. As a result, the drag losses of the engine can be significantly reduced and it can, for example, be recovered in hybrid drives more energy on the crank mechanism. It should be noted that in this case the closing of the two valves of a respective cylinder need not necessarily be simultaneous.

Preferably, the device is z. B. by means of at least one measuring device adapted to measure at least one temperature, wherein the control unit is adapted to check for detecting the Untertemperierung, whether the measured temperature is below a predetermined minimum temperature. As will be discussed below, the measured temperature may in particular be a temperature of the internal combustion engine, an exhaust system connected thereto or a fluid which is in contact with the components mentioned. In any case, the measured temperature gives at least approximately information about the temperature of the catalyst. The minimum temperature is a (normally factory default) temperature value chosen to allow the catalyst to not be sufficiently warmed up when the measured temperature is below the minimum temperature. The minimum temperature is stored within the device, usually within the control unit itself, and can be compared by the control unit with the measured temperature. It is understood that the device must comprise at least one temperature sensor, via which the said temperature is measured. In principle, there are no restrictions with regard to the type of temperature sensor. In particular, if necessary, a non-contact measurement can also take place. Of course, a plurality of temperature sensors may be present. It is conceivable that in the case of multiple temperature sensors, which measure at different locations, an individual minimum temperature is set for each temperature sensor. If the control unit determines that the measured temperature is below the (associated) minimum temperature, it recognizes that the catalyst is under temperature control.

According to a preferred embodiment, the device z. B. by means of at least one measuring device configured to measure a temperature of the catalyst. This can be used to determine exactly, which temperature the catalyst has, directly and within the scope of the measurement accuracy. This allows a very reliable conclusion on whether the catalyst is sufficiently warmed up or whether there is a sub-tempering. In this case, the temperature measurement does not necessarily have to take place directly on the catalytically active material, but may, for example, also be carried out on a carrier element to which this is applied. Normally, it can be assumed that the temperature of the carrier element and that of the (in the chemical sense) actual catalyst are virtually identical.

In this case, the minimum temperature preferably corresponds to at least one activation temperature of the catalyst. The activation temperature is the temperature above which the catalyst operates with optimum effectiveness. It can also be considered that, at least in some cases, this activation temperature during warming is higher than, conversely, during cooling, so there is a kind of "hysteresis" here. The activation temperature depends on the type of catalyst. The activation temperature may in particular be between 150 ° C and 250 ° C. In particular, it is possible that the minimum temperature is above the activation temperature, so that, so to speak, a safety margin is planned to ensure that the catalyst is activated in each case. Some catalysts work optimally only in a certain temperature range. Ie. above a temperature, which is referred to as overheating temperature in this context, they work Catalysts no longer optimal. In particular, to take this into account, the minimum temperature may be chosen to be between the activation temperature and the superheat temperature. The superheating temperature is of course dependent on the type of catalyst and also does not correspond to an exact temperature value, since the overheating, ie the loss of effectiveness of the catalyst, takes place over a certain temperature range.

In another embodiment, the device is z. B. by means of the measuring device configured to measure an exhaust gas temperature. The exhaust gas temperature can be measured in particular downstream of the catalyst, but measurements at other locations are possible. The term "exhaust gas temperature" does not refer exclusively to gas mixtures which contain partially or predominantly combustion products of the internal combustion engine, but to any gas that is in the exhaust system of the internal combustion engine (including any existing EGR line), ie downstream of the exhaust valve or the exhaust valves. In the case of an overrun fuel cutoff, this may therefore essentially also be fresh air which has been passed through the engine without a combustion process.

According to a further embodiment, the device z. B. by means of at least one measuring device configured to measure a temperature of an exhaust pipe, which is at least indirectly connected to the catalyst. In this case, the term "exhaust gas line" encompasses all exhaust-carrying elements from the manifold to the tailpipe, as well as a possibly existing exhaust gas recirculation (EGR) line Preferably, the measurement follows in an exhaust gas line which is directly connected to the catalytic converter, ie without the interposition of further components. In this case, the temperature can be measured in particular in a part of the exhaust gas line which adjoins the catalyst, but also a measurement of the temperature in regions further away from the catalyst allows at least certain conclusions to be drawn about the temperature of the catalyst To close the sub-tempering, without measuring the temperature of the catalyst itself.

The warm-up and cool-down behavior of the catalyst is coupled to that of the internal combustion engine to some extent. Therefore, according to a further embodiment, the device z. B. by means of at least one measuring device configured to measure a temperature of the internal combustion engine. Of course, not all parts of the internal combustion engine generally have the same temperature. In this respect, "temperature of the internal combustion engine" should be understood to mean the temperature of a particular part of the engine where the measurement is made. It may be useful in this case to measure the temperature in a part of the engine that is as close as possible to the exhaust-carrying parts. This could, for example, be an outlet line of a cylinder.

In addition to a direct measurement of the engine temperature, the device z. B. by means of at least one measuring device, for example. Also be adapted to measure a coolant temperature. This also allows at least limited conclusions about the temperature of the engine and the temperature of the catalyst.

Preferably, in the described embodiments, in which the temperature of the catalyst itself, but that of another component or of the exhaust gas is not measured, the predetermined minimum temperature is chosen so that it is above the activation temperature of the catalyst. In particular, the temperature of the engine will be higher than that of the catalyst in almost all cases, so that a corresponding minimum temperature should be above the activation temperature of the catalyst here. The temperature of exhaust gases is also above the temperature of the catalyst, provided that the exhaust gases come from a normal operating phase of the engine (without fuel cut-off). Therefore, also in this case, the minimum temperature should be greater than the activation temperature of the catalyst. If the temperature of the exhaust gas line is measured, the closer the temperature measurement takes place to the activation temperature, the closer the activation temperature to the minimum temperature. Ie. if a measured in a section of the exhaust pipe, which is close, so close to the catalyst, the minimum temperature may substantially correspond to the activation temperature, while at a measurement in a more distant section, the minimum temperature should be chosen to be safer.

All of the above temperature measurements can be combined if necessary. Here, two or more measurements can be combined. This applies in particular to cases in which the temperature of the catalyst is not measured directly.

In addition to a temperature measurement can in principle be concluded from the previous operation of the engine, whether the catalyst is currently sufficiently warmed up or not. For example, it is clear shortly after a cold start of the engine that the catalyst can not yet be sufficiently warmed up. The actual temperature of the catalyst is of course dependent on various factors, such as. Ambient temperature, length and other design of the Exhaust line between engine and catalyst etc. At least approximately, however, the temperature can be estimated from operating data of the internal combustion engine within a past time interval (eg the last quarter of an hour). Therefore, according to a further embodiment, the device z. B. by means of a separate memory unit adapted to detect and store operating data of the internal combustion engine, wherein the control unit is adapted to detect the Untertemperierung based on stored operating data. The storage unit may also be integrated in the control unit. In particular, the operating data may include data on the duration and start of the driven phases, the amount of fuel supplied, and the duration and start of the phases with fuel cut. The corresponding data are stored (if necessary by the control unit itself), so that they can be called up in each case for a past time interval. The control unit retrieves the corresponding data and determines from this at least approximately whether the catalyst is sufficiently warmed up or is still under temperature or again. If necessary, the operating data can also be combined with other data, for example with an ambient temperature.

Further advantageous details and effects of the invention are explained below with reference to an embodiment shown in the single figure. It shows:

1 a schematic representation of a device according to the invention and an internal combustion engine and an exhaust system.

1 shows a schematic representation of an internal combustion engine 10 of a motor vehicle, simplifying only one cylinder 11 with an inlet pipe 14 , an outlet pipe 15 , an inlet valve 16 and an exhaust valve 17 is shown. It is understood that the internal combustion engine 10 usually a plurality of cylinders 11 and intake and exhaust valves per cylinder. The inlet pipe 14 is with a suction line 13 connected for fresh air. To the outlet pipe 15 closes an exhaust system 20 on, which is also shown here greatly simplified. The exhaust system 20 points next to exhaust pipes 21 . 22 Exhaust after-treatment devices, such. B. an intermediate catalyst 23 on, for the catalytic treatment of exhaust gases of the internal combustion engine 10 serves. In the following, the exhaust aftertreatment device is used as a catalyst 23 Particle filter etc. should also be included in the invention. This may be any type of catalyst, for example an oxidation catalyst. The catalyst 23 In any case, shows a typical warm-up behavior, which becomes active only from an activation temperature which is substantially above the ambient temperature.

Furthermore, a control unit 30 to recognize that together with measuring devices, such. B. temperature sensors 31 - 34 to a device 1 for controlling the engine 10 belongs. The control unit 30 is with several control lines 36 connected. Via a control line 36 this controls an injector 18 to the fuel supply of the internal combustion engine 10 to regulate. In normal operation, ie when, for example, a (not shown) accelerator pedal is actuated, is via the injection valve 18 Fuel injected, the internal combustion engine 10 sucks over the suction line 13 and the inlet pipe 14 Fresh air, burns fuel and gives the exhaust gases through the outlet 15 in the exhaust system 20 from. Here are the valves 16 . 17 alternately opened and closed in a known manner. Of course, the internal combustion engine 10 Also be designed as a turbocharged engine, so that should be included in the invention not only naturally aspirated.

If the accelerator pedal is not actuated and the speed of the internal combustion engine 10 exceeds a certain value, so interrupts the control unit 30 the fuel supply, ie there is a fuel cutoff instead. In this case, the internal combustion engine is moving 10 continue without generating a driving force. However, the pistons are moving too 12 in the cylinders 11 further. Would the intake and exhaust valves 16 . 17 as in normal operation would continue to open and close, would via the inlet pipe 14 Fresh air sucked in and without significant heating via the outlet line 15 in the exhaust system 20 issued. This would cause a cooling (or a delay in the heating) of the catalyst 23 to lead. This is particularly harmful if a temperature of the catalyst 23 is below the activation temperature.

To avoid this, the control unit is 30 over one of several sensor lines 35 with a first temperature sensor 31 connected to the catalyst 23 is arranged and measures a first temperature of the same. In the control unit 30 a first minimum temperature is stored with which the measured first temperature is compared. The first minimum temperature corresponds to at least the activation temperature of the catalyst 23 In particular, it can also be higher and thus correspond to a temperature range in which the catalyst 23 works optimally. Represents the control unit 30 determines that the measured first temperature is less than the first minimum temperature, it rates this as a sub-tempering of the catalyst 23 , If such a low temperature control is detected with simultaneous fuel cut, the control unit controls 30 the inlet valves 16 as well as the exhaust 17 all cylinders 11 so that they are closed and remain closed until either the fuel cut-off has ended or there is no longer a lower temperature control. Here, the intake and exhaust valves 16 . 17 be closed simultaneously or in succession. There may also be a certain delay between the detection of over-temperature control and fuel cut-off on the one hand and the closing of the valves 16 . 17 on the other hand. Closing the valves 16 . 17 causes no fresh air through the internal combustion engine 10 in the exhaust system 20 arrives. Thus, a cooling of the catalyst 23 effectively counteracted. Possibly. can the catalyst 23 even during overrun fuel cutoff in the exhaust system 20 hot exhaust gases are further heated. Thus, the catalyst reaches 23 For example, after a cold start a temperature at which he works effectively.

The illustrated temperature measurement directly on the catalyst 23 In general, the preferred method is to detect a sub-ambient temperature. However, there are other possibilities. Thus, for example, a second temperature sensor 32 on the combustion engine 10 be arranged to measure a second temperature. For example. can the second temperature sensor 32 in the area of the outlet pipe 15 be arranged. The second temperature measured there provides information about the temperature of the catalyst to a certain extent 23 , Therefore, the second temperature with one in the control unit 30 deposited second minimum temperature compared to a supercooling of the catalyst 23 determine. On the one hand to take into account that the internal combustion engine 10 generally warmer than the catalyst 23 is and on the other hand, a temperature measurement away from the catalyst 23 there is some uncertainty, the second minimum temperature can be set much higher than the first minimum temperature.

Another option is to use a third temperature sensor 33 a third temperature in the exhaust system 20 to eat. The third temperature sensor 33 may, for example, immediately upstream adjacent to the catalyst 23 at the exhaust pipe 21 be arranged. The temperature in this range usually differs only slightly from the temperature of the catalyst 23 why a corresponding third minimum temperature can be chosen to be relatively similar to the first minimum temperature.

Alternatively or additionally, via a fourth temperature sensor 34 a fourth temperature of the exhaust gas within the exhaust pipe 22 immediately downstream of the catalyst 23 be measured. This also allows at least approximately a conclusion on the current temperature of the catalyst 23 , A fourth minimum temperature used for the comparison can again be selected to be significantly higher than the first minimum temperature for safety reasons.

The temperature sensors shown here 31 - 34 Normally not all are used at the same time; In particular, usually at a temperature measurement on the catalyst 23 on the second, third and fourth temperature sensor 32 . 33 . 34 be waived.

In addition to a temperature measurement can also from the operating data of the internal combustion engine 10 a conclusion on the temperature of the catalyst 23 to be pulled. For this purpose, the control unit 30 Save data on the time, duration and amount of fuel supplied and time and duration of the phases with fuel cut, or query from a separate storage unit. From these data can be estimated, if necessary in conjunction with a determined ambient temperature, whether a low temperature of the catalyst 23 present or not. Of course, the data does not have to be stored arbitrarily long, but it can be deleted older data that affect time intervals, the temperature of the catalyst 23 can not influence.

Regardless of which of the options shown is used to detect a Untertemperierung, is through the device 1 a much more effective function of the catalyst 23 and thus ensures a reduction of harmful exhaust gas components.

LIST OF REFERENCE NUMBERS

1

 contraption

10

 engine

11

 cylinder

12

 piston

13

 suction

14

 inlet line

15

 outlet pipe

16

 intake valve

17

 outlet valve

18

 Injector

20

 exhaust system

21, 22

 exhaust pipe

23

 catalyst

30

 control unit

31-34

 Measuring device / temperature sensor

35

sensor line

36

control line

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

• JP 2004-169646 A [0004]
• JP 2009-121433 A [0005]
• EP 2792865 A1 [0006]

Claims (10)

Contraption ( 1 ) for controlling an internal combustion engine ( 10 ), which has at least one cylinder ( 11 ) with an inlet valve ( 16 ) and an outlet valve ( 17 ) and the at least one catalyst ( 23 ) downstream of the exhaust aftertreatment, wherein the device ( 1 ) a control unit ( 30 ), characterized in that the control unit ( 30 ) is set up, - a sub-tempering of the catalyst ( 23 ), and - at least one valve (in the presence of a lower temperature control and an overrun fuel cut-off) ( 16 . 17 ) of each cylinder ( 11 ) close and keep closed. Device according to claim 1, characterized in that the control unit ( 30 ) is adapted to both valves ( 16 . 17 ) of each cylinder ( 11 ) close. Apparatus according to claim 1 or 2, characterized by at least one measuring device ( 31 - 34 ) which is adapted to measure at least one temperature, wherein the control unit ( 30 ) is set up to check whether the measured temperature is below a predetermined minimum temperature for detecting the low-temperature control. Device according to one of the preceding claims, characterized by a measuring device ( 31 ), which is adapted to a temperature of the catalyst ( 23 ) to eat. Device according to one of the preceding claims, characterized by a measuring device ( 34 ), which is adapted to measure an exhaust gas temperature. Device according to one of the preceding claims, characterized by a measuring device ( 33 ), which is adapted to a temperature of an exhaust pipe ( 21 . 22 ), which at least indirectly with the catalyst ( 23 ) connected is. Device according to one of the preceding claims, characterized by a measuring device ( 32 ), which is adapted to a temperature of the internal combustion engine ( 10 ) to eat. Device according to one of the preceding claims, characterized in that a predetermined minimum temperature of at least one activation temperature of the catalyst ( 23 ) and is between 150 ° C and 250 ° C. Device according to one of the preceding claims, characterized in that a predetermined minimum temperature above an activation temperature of the catalyst ( 23 ) lies. Device according to one of the preceding claims, characterized by a memory unit which is adapted to operating data of the internal combustion engine ( 10 ) and to store, the control unit ( 30 ) is adapted to detect the low-temperature control based on stored operating data.

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