DE102017206162A1 - Device for controlling a diesel engine and a storage catalytic converter connected downstream of the diesel engine - Google Patents

Abstract

The invention relates to a device (1) for controlling a diesel engine (10) having a plurality of cylinders (11 - 14) and a storage catalytic converter (23) downstream of the diesel engine (10) for exhaust aftertreatment, the device (1) comprising a control unit (30 ). In order to reduce the emission of pollutants, in particular nitrogen oxides, in a diesel engine, it is provided according to the invention that the control unit (30) is set up to:
to check whether a regeneration of the storage catalytic converter (23) is necessary,
- To determine a catalyst temperature in the region of the storage catalyst (23), and
- Upon detection of a Untertemperierung, in which the catalyst temperature falls below a necessary regeneration temperature, a part of the cylinder (11-14) turn off and then initiate the regeneration.

Description

The invention relates to a device for controlling a diesel engine having a plurality of cylinders and a downstream of the diesel engine storage catalyst for exhaust aftertreatment, having the features of the preamble of claim 1.

In modern diesel engines different devices are used, which contribute to the reduction of pollutant emissions. These include, for example, particulate filters or catalysts for selective catalytic reduction (SCR), in which a reducing agent (eg, ammonia or ammonia precursor such as a urea-water solution) is injected into the exhaust gas stream and to suitable catalysts with nitrogen oxides to less harmful products (in the case of ammonia as a reducing agent: to nitrogen and water) to be implemented. Another device is a NO _x storage catalyst and _NOx absorber, which is also referred to as LNT catalyst (lean _NOx trap). Such an LNT catalyst comprises, in addition to a catalyst, an NO _x storage component. Through this nitrogen oxides are absorbed, while the engine control works mainly in a "lean", so comparatively low-fuel phase. As soon as the storage component is fully occupied, it can no longer absorb any further nitrogen oxides and must be actively regenerated. In the course of regeneration, the stored nitrogen oxides are released and, for example, reacted together with hydrocarbons, for example, nitrogen and water are generated. For this purpose, a "rich" phase with substoichiometric oxygen concentration can be set via the engine control. For the regeneration underlying reaction to proceed efficiently, a certain temperature in the range of the LNT catalyst is necessary.

LNT catalysts are now commonly used in medium and high-end diesel vehicles to meet emission standards. The requirements of newer RDE tests (Real Drive Emission) include a test of the vehicle under different driving conditions (eg city center / highway / motorway). Therefore, it will be necessary in the future to carry out a regeneration of LNT catalysts in almost all operating states of the engine. However, the exhaust gas temperature is often not high enough for adequate regeneration, especially in urban traffic due to the low load requirements. RDE tests are also carried out under cold ambient conditions (down to -7 ° C), which can lead to additional cooling of the exhaust system by the cold ambient air.

The CH 710 284 A1 discloses a cylinder deactivation multi-cylinder diesel engine having an exhaust aftertreatment system, wherein the cylinder deactivation shuts down at least one cylinder to increase the exhaust temperature of the diesel engine if a measured temperature in the exhaust after-treatment system is below a certain value. In this case, an SCR and a particulate filter are mentioned as exhaust aftertreatment system. By increasing the exhaust gas temperature on the one hand to ensure an effective operation of the SCR, on the other hand, a Rußabbrand be supported in the particulate filter. A similar system is from the US 5,930,992 A known, among other things, it is provided that the cylinders are alternately switched off to prevent complete cooling of individual cylinders.

The US 9,376,967 B2 discloses a self-igniting internal combustion engine having at least two groups each having at least one cylinder. The cylinders of the two groups are characterized by different compression ratios. It is envisaged that with a partial shutdown in the lower part load range, the cylinders of the group with the larger compression ratio remain in operation.

The US 6,931,839 B2 discloses an exhaust aftertreatment system for a cylinder deactivation engine as well as a catalytic aftertreatment system. If it is determined that the engine is in a cold start phase, it is envisaged that a portion of the cylinders will be shut down to increase the exhaust gas temperature in the region of the aftertreatment system to operate efficiently.

From the US 2013/0199466 A1 For example, an internal combustion engine is known having four cylinders arranged in series, which are configured in two groups, with one outer cylinder and the adjacent inner cylinder forming a group. The two crankshaft cranks of the two cylinders of each cylinder group have no offset in the circumferential direction about the longitudinal axis of the crankshaft, so that the cylinders of a cylinder group are mechanically synchronous cylinders. In contrast, the crankshaft cranks of the one cylinder group with respect to the crankshaft cranks of the other cylinder group are circumferentially offset by 180 ° on the crankshaft. Advantageously, an exhaust aftertreatment takes place, for example by means of an LNT catalyst.

The summary of the dissertation "Thermal efficiency and emission analysis of advanced thermodynamic strategies in a multicylinder diesel engine utilizing valvetrain flexibility" by C. Ding, Purdue University, describes investigations such as the efficiency of exhaust aftertreatment systems can be optimized under different conditions. It is provided, inter alia, that exhaust gas recirculation (EGR), late closing of an intake valve (LIVC) and cylinder deactivation (CDA) increase the temperature in the exhaust gas aftertreatment system.

In view of the above-mentioned prior art, a more effective reduction in the production or emission of pollutants, in particular nitrogen oxides, in a diesel engine still offers room for improvement. This applies in particular to the increase in the effectiveness of a storage catalyst used

The invention has for its object to reduce the emission of pollutants, especially nitrogen oxides in a diesel engine.

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 figure.

The invention provides a device for controlling a diesel engine and a storage catalytic converter connected downstream of the diesel engine. The diesel engine has a plurality of cylinders. Of course, each cylinder has at least one inlet valve and at least one outlet valve. In particular, it may be a diesel engine of a motor vehicle, for example a car or truck. The diesel engine is followed by a storage catalytic converter for exhaust aftertreatment. It is understood that the storage catalyst may be one of several components of an exhaust aftertreatment system, which may include, for example, other catalysts, particulate filters and / or catalytic particulate filters. In this case, several components of the exhaust aftertreatment system in the flow direction of the exhaust gases can be arranged sequentially or possibly also parallel to each other in the exhaust line.

The storage catalytic converter is in any case arranged downstream of the diesel engine. If it is a diesel engine with exhaust gas recirculation (EGR), the storage catalytic converter can also be located in an exhaust gas recirculation line. Of course, the storage catalytic converter is part of an exhaust system of the diesel engine, with any EGR line that may be present being considered as part of the exhaust system. In principle, this may be any type of storage catalytic converter which is suitable for exhaust aftertreatment of diesel engines. In particular, it may be a nitrogen oxide storage catalyst or LNT catalyst. It can also be provided several storage catalytic converters.

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 this case, if necessary, different components of the control unit can be spaced apart from each other and, for example, be interconnected by bus lines. 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 check in a first step whether regeneration of the storage catalytic converter is necessary. This may, for example, be the case when the storage catalytic converter is completely loaded or its loading state has reached a predetermined threshold, for example 90%. The determination of whether regeneration is necessary can take place in different ways. For example. the loading state can be calculated by means of a mathematical model, in which various input variables such as the raw nitrogen oxide emission of the diesel engine, the previous absorption period, the exhaust gas mass flow and the exhaust gas temperature can enter. Alternatively, the control unit can also access measured values of a nitrogen oxide sensor which is installed in the exhaust gas flow downstream of the storage catalytic converter.

Furthermore, the control unit is set up to determine a catalyst temperature in the region of the storage catalytic converter. The catalyst temperature is either a temperature of the storage catalyst itself or a temperature of its immediate environment. In any case, it is the temperature that prevails in the area of the planned regeneration and thus is decisive for whether a regeneration can be carried out successfully. As will become clear from the following description, it is not absolutely necessary for this that the temperature of the storage catalytic converter itself be measured. Rather, it can also be concluded indirectly on the catalyst temperature, which in principle can remain a certain margin for error.

Furthermore, the control unit is set up when a lower temperature control is detected the catalyst temperature falls below a necessary regeneration temperature, turn off a portion of the cylinders and then initiate regeneration. As already mentioned above, in particular an indirect determination of the catalyst temperature can lead to errors, so that the control unit, if necessary, incorrectly recognizes or incorrectly recognizes a sub-tempering in individual cases. Thus, "detection" in this context means that the control unit evaluates the state of the storage catalytic converter as a sub-tempering, that is to say that its temperature lies below the regeneration temperature. In this case, this regeneration temperature may in particular be higher than an activation temperature of the storage catalytic converter which it requires in order to store the corresponding exhaust gas component. Ie. In comparison with the normal operation of the storage catalytic converter, an increased temperature may be necessary for the regeneration. If the catalyst temperature is below the regeneration temperature and still attempts to initiate the regeneration, this can lead to a significant deterioration of the exhaust gas values. In the case of a nitrogen oxide storage catalyst, this z. B. cause previously stored nitrogen oxides released again, but not implemented as intended to elemental nitrogen (and other substances). In other words, in this case, the release of the nitrogen oxides would only be delayed and the function of the storage catalyst would be negated.

The efficiency of the regeneration depends on the exhaust gas temperature reached during the regeneration. By deactivating cylinders, efficient regeneration in low-load operation can thus be triggered under thermal consideration. In many cases, fat engine operation is difficult to set even in low-load operation in diesel engines. Cylinder deactivation goes hand in hand with enrichment and therefore also has a positive effect on regeneration under this aspect. Therefore, the control unit shuts off a portion of the cylinders, thereby increasing the load on the remaining cylinders. This in turn leads to an increase in the temperature of the remaining cylinders and the temperature of the exhaust gases generated, which flow past the storage catalytic converter in the further course. Thus, the cylinder deactivation also leads to an increase in the catalyst temperature with a certain delay. After the control unit has switched off a part of the cylinders as described, it initiates the regeneration of the storage catalytic converter. The initiation of the regeneration means, for example, in the case of a nitrogen storage catalytic converter, that the control unit sets a substoichiometric oxygen concentration or an increased fuel concentration. Normally, the initiation of regeneration occurs with a time lag from the shutdown of the cylinders to allow time for the storage catalyst to warm up sufficiently. The time delay is generally dependent on the conditions of the diesel engine and the exhaust system, part of which is the storage catalytic converter. It can be determined beforehand experimentally and stored at the factory or possibly also calculated (eg by the control unit). The shutdown of the cylinder normally involves a shutdown of the fuel supply to the corresponding cylinder and a closing of the associated intake valve and / or exhaust valve. Embodiments are conceivable in which the catalyst temperature does not reach the regeneration temperature in some cases, but at least approaches it, so that an at least partially successful regeneration is possible. This can be z. B. in a nitrogen storage catalyst mean that all stored nitrogen oxides are released, although only a part is converted to elemental nitrogen. Even in such a case can be reduced by the inventively provided cylinder shutdown of the emission of harmful exhaust gases.

In principle, a necessary time delay between the switching off of a part of the cylinders and the initiation of the regeneration can be estimated. However, this can lead to errors that can be relatively easily avoided. Preferably, the control unit is therefore configured to check after switching off whether the regeneration temperature has been reached before it initiates the regeneration. In other words, the control unit is configured to re-determine the catalyst temperature after the shutdown and to perform the regeneration only when the regeneration temperature has been reached. In this case, the determination of the catalyst temperature can take place repeatedly or continuously.

Under certain circumstances, the cylinders of the diesel engine can be switched off in stages, for example. Such that in an eight-cylinder engine optionally 2, 4 or 6 cylinders can be switched off. In such a case, it is possible that at the time when the control unit determines that the catalyst temperature is below the regeneration temperature, a part of the cylinders is already turned off. This could be done, for example, for reasons of power reduction. According to one embodiment of the invention, the control unit may be set up, if a sub-tempering is present and already a part of the cylinder is turned off, at least turn off another cylinder. By this measure, the load for the remaining in operation cylinder is further increased and the exhaust gas temperature can be further increased.

In the context of the present invention, the cylinder deactivation or additional cylinder deactivation is normally a temporary measure which serves to support the time-limited regeneration of the storage catalytic converter. The control unit is therefore preferably configured to switch on at least a part of the cylinders again after the end of the regeneration. For example. For example, it is conceivable that some of the cylinders (eg, 2 out of 8 cylinders) have already been shut down, and the control unit has increased the number of deactivated cylinders for regeneration purposes (eg, 4 out of 8). In such a case z. B. after regeneration as many cylinders are turned on again, as were turned off to prepare for the regeneration.

The control unit is preferably configured to measure at least one temperature by means of at least one measuring device and to check whether the measured temperature lies below a predetermined minimum temperature in order to detect the low-temperature control. As will be discussed below, the measured temperature may be, in particular, a temperature of the diesel engine, an exhaust system connected thereto, or a fluid in contact with said components. In any case, the measured temperature gives at least approximately information about the catalyst temperature. The minimum temperature is a (normally factory default) temperature value that is chosen to allow the storage catalyst to be insufficiently heated for regeneration 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 measuring device, for example a temperature sensor, by means of 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 that measure at different locations, an individual minimum temperature is set for each temperature sensor. If the control unit detects that the measured temperature is below the (associated) minimum temperature, it recognizes that there is a sub-tempering.

The control unit can measure the at least one temperature by means of different measuring devices, which implies that the corresponding temperature can be measured at different locations. According to a preferred embodiment, a measuring device is set up to measure the catalyst temperature. By means of this it can be determined directly and (within the scope of the measuring accuracy) exactly what temperature the storage catalytic converter has. This allows a very reliable conclusion as to whether the storage catalytic converter is sufficiently warmed up or whether there is a subsaturation. 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 one can assume that the temperature of the carrier element and that of the (in the chemical sense) actual storage catalyst are virtually identical.

In this case, the minimum temperature preferably corresponds at least to the regeneration temperature of the storage catalytic converter. In particular, it is possible for the minimum temperature to be above the regeneration temperature, so that, as it were, a safety margin is planned in order to ensure that the regeneration can be carried out successfully in any case.

In another embodiment, a measuring device is configured to measure an exhaust gas temperature. The exhaust gas temperature can be measured in particular downstream of the storage catalytic converter, although measurements at other locations are also possible. The term "exhaust gas temperature" does not refer exclusively to gas mixtures that contain partially or predominantly combustion products of the diesel engine, but to any gas that is in the exhaust system of the diesel 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, a measuring device is adapted to measure a temperature of an exhaust pipe, which is at least indirectly connected to the storage catalytic converter. Here, the term "exhaust pipe" includes all exhaust gas leading elements from the manifold to the tailpipe, as well as any existing exhaust gas recirculation (EGR). Preferably, the measurement follows in an exhaust pipe, which is connected directly to the storage catalytic converter, ie without the interposition of further components. The temperature can be measured in particular in a part of the exhaust pipe, which adjoins the storage catalyst. But also a measurement of the temperature in further from the storage catalytic converter At least some conclusions about the catalyst temperature are possible. It is thus possible to conclude a low-temperature control without measuring the catalyst temperature itself.

The warm-up and cool-down behavior of the storage catalyst is coupled to that of the diesel engine to some degree. Therefore, according to a further embodiment, a measuring device is adapted to measure a temperature of the diesel engine. Of course, not all parts of the diesel engine generally have the same temperature. As such, "temperature of the diesel 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, a measuring device can also be set up to measure a coolant temperature. Again, this allows at least limited conclusions about the temperature of the engine and the temperature of the storage catalyst.

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

All of the above temperature measurements can be combined if necessary. Here, two or more measurements can be combined. This is especially true in cases where not directly the catalyst temperature is measured.

In addition to a temperature measurement can in principle be closed on the previous operation of the engine, whether the storage catalyst is currently sufficiently warmed up or not. For example, it is clear shortly after a cold start of the engine that the storage catalytic converter can not yet be sufficiently warmed up. The actual temperature of the storage catalytic converter is, of course, dependent on various factors, such as ambient temperature, length and other design of the exhaust gas line between engine and storage catalytic converter, etc. At least approximately, however, the temperature may be from operating data of the diesel engine within a past time interval (eg the last quarter hour). be estimated. Therefore, according to a further embodiment, the device (eg by means of a separate or integrated into the control unit memory unit) is adapted to detect and store operating data of the diesel engine, wherein the control unit is adapted to detect the Untertemperierung based stored operating data. 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 at least approximately whether the storage catalytic converter is sufficiently warmed up for successful regeneration. If necessary, the operating data can also be combined with other data, for example with an ambient temperature.

• 1 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung sowie eines Dieselmotors und einer Abgasanlage.

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 a diesel engine and an exhaust system.

1 shows a schematic representation of a diesel engine 10 of a motor vehicle, wherein simplifying four cylinders 11 - 14 are shown. Each of the cylinders 11-14 is via an inlet conduit 15 with a suction line 16 for fresh air, the access to the respective cylinder 11-14 being controlled by an intake valve, not shown here. Furthermore, each cylinder 11-14 is via an outlet conduit 17 with an exhaust system 20 connected, which is shown here greatly simplified. The access from the respective cylinder 11-14 to the outlet line 17 is about a likewise not shown Exhaust valve controllable. The exhaust system 20 points aside from two exhaust pipes 21 . 22 also exhaust after-treatment devices, wherein here simplistic only designed as a nitrogen oxide storage catalyst storage catalyst 23 is shown, for storing and catalytic treatment of exhaust gases of the diesel engine 10 serves.

Furthermore, a control unit 30 to recognize that together with measuring devices, such. As 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 it controls the intake valves, exhaust valves and also not shown injection valve of the respective cylinder 11 - 14 to control their operation. In normal operation, ie when, for example, a (not shown) accelerator pedal is actuated, fuel is injected, the diesel engine 10 sucks over the suction line 16 and the inlet pipes 15 Fresh air, burns fuel here and gives the exhaust gases through the outlet pipes 17 in the exhaust system 20 from. Here, the inlet and outlet valves are opened and closed alternately in a known manner. Of course, the diesel engine 10 Also be designed as a turbocharged engine, so that should be included in the invention not only naturally aspirated.

A proportion of the exhaust gases are nitrogen oxides, the delivery of which to the environment is undesirable. These are at least predominantly from the storage catalyst 23 absorbed, for example in the form of nitrates. After a certain period of operation is the storage catalyst 23 fully or substantially loaded, so that its ability to absorb nitrogen oxides is at least limited. Therefore, at certain intervals, a regeneration of the storage catalytic converter 23 be made, the control unit 30 over the control lines 36 a lower mixing ratio between oxygen and fuel, thereby unburned fuel in the area of the exhaust system 20 arrives. If the catalyst temperature corresponds to at least one necessary regeneration temperature, the previously stored nitrogen oxides are released and catalytically reacted with fuel residues to elemental nitrogen and other substances that are environmentally friendly or less questionable.

The control unit can either estimate the amount of stored nitrogen oxides on the basis of data on the previous engine power, the fuel consumption, etc., or it can via a nitrogen oxide sensor, not shown here, in an exhaust pipe 22 behind the nitrogen oxide storage catalyst 23 is arranged to determine the extent to which the latter still absorbs nitrogen oxides. In this way, the control unit 30 Determines whether regeneration must be performed.

However, if the catalyst temperature falls below the regeneration temperature, this has a detrimental effect on the regeneration, for example, such that although nitrogen oxides are released, but not converted.

In order to avoid such a sub-tempering at the time of regeneration, the control unit 30 over one of several sensor lines 35 connected to a first temperature sensor 31 which is connected to the storage catalytic converter 23 is arranged and measures the catalyst temperature. In the control unit 30 a first minimum temperature is stored with which the measured catalyst temperature is compared. The first minimum temperature corresponds to at least the regeneration temperature. Represents the control unit 30 determines that the measured catalyst temperature is less than the first minimum temperature, it rates this as a sub-tempering of the storage catalyst 23 , If such a temperature control is detected, the control unit switches 30 over the control lines 36 two cylinders 12, 14. This increases the load of the remaining in operation two cylinders 11, 13, whereby the temperature of these cylinders and the temperature of the exhaust gases increases. This in turn leads to a heating of the storage catalyst 23 whose catalyst temperature thus approaches the regeneration temperature.

The control unit 30 after switching off a portion of the cylinders 11-14 again determines the catalyst temperature to check whether the regeneration temperature has been reached. In particular, the catalyst temperature can be determined repeatedly within short time intervals. Once the regeneration temperature is reached, the control unit will conduct 30 the regeneration. After this is completed, the previously disabled cylinders 12, 14 are switched on again.

According to an alternative scenario, it could be that, for example, at the time when the control unit 30 In this case, the control unit may shut off an additional cylinder 12 (or more) to further increase the load on the remaining cylinders 11, 13.

The illustrated temperature measurement directly on the storage catalytic converter 23 In general, the preferred method is to detect a sub-ambient temperature. However, there are other possibilities. For example, a second temperature sensor 32 on the diesel engine 10 disposed be to measure a second temperature. For example. For example, the second temperature sensor 32 may be in the region of the outlet line 17 be arranged. The second temperature measured there provides information about the temperature of the storage catalytic converter to a certain extent 23 , Therefore, the second temperature with one in the control unit 30 deposited second minimum temperature compared to a subsaturation of the storage catalyst 23 determine. On the one hand to take into account that the diesel engine 10 generally warmer than the storage catalyst 23 and on the other hand, a temperature measurement away from the storage catalyst 23 there is some uncertainty, the second minimum temperature can be set much higher than the first minimum temperature.

Another possibility is, via 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 of adjacent to the storage catalyst 23 at the exhaust pipe 21 be arranged. The temperature in this range usually differs only slightly from the temperature of the storage 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 storage catalyst 23 be measured. This also allows at least approximately a conclusion on the current temperature of the storage 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 at the storage catalyst 23 to the second, third and fourth temperature sensor 32, 33, 34 are omitted.

In addition to a temperature measurement can also from the operating data of the diesel engine 10 a conclusion on the temperature of the storage 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, it can be estimated, if necessary in conjunction with a determined ambient temperature, whether or not a subsaturation of the storage catalytic converter 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 on the temperature of the storage catalytic converter 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 storage catalyst 23 and thus ensures a reduction of harmful exhaust gas components.

LIST OF REFERENCE NUMBERS

1

contraption

10

diesel engine

11-14

cylinder

15

inlet line

16

suction

17

outlet pipe

20

exhaust system

21.22

exhaust pipe

23

storage catalytic converter

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

• CH 710284 A1 [0004]
• US 5930992 A [0004]
• US 9376967 B2 [0005]
• US 6931839 B2 [0006]
• US 2013/0199466 A1 [0007]

Claims (10)

Device (1) for controlling a diesel engine (10) having a plurality of cylinders (11-14) as well as a diesel engine (10) downstream of the storage catalyst (23) for exhaust gas aftertreatment, said device (1) comprises a control unit (30), characterized characterized in that the control unit (30) is adapted to: - check whether a regeneration of the storage catalytic converter (23) is necessary, - determine a catalyst temperature in the region of the storage catalytic converter (23), and - detect a subsaturation, in which the Catalyst temperature is below a necessary regeneration temperature to turn off a portion of the cylinder (11 - 14) and then initiate the regeneration. Device after Claim 1 , characterized in that the control unit (30) is adapted to check after shutdown whether the regeneration temperature has been reached before initiating the regeneration. Device after Claim 1 or 2 , characterized in that the control unit is adapted to, if already a part of the cylinder (11 - 14) is switched off and there is a Untertemperierung, at least one further cylinder (11 - 14) off. Device according to one of the preceding claims, characterized in that the control unit (30) is adapted to turn on after the end of the regeneration at least a part of the cylinder (11 - 14) again. Device according to one of the preceding claims, characterized in that the control unit (30) is adapted to measure by means of at least one measuring device (31 - 34) at least one temperature and to detect the lower temperature control to check whether the measured temperature below a predetermined minimum temperature lies. Device after Claim 5 , characterized in that a measuring device (31) is adapted to measure the catalyst temperature. Device after Claim 5 or 6 , characterized in that a measuring device (34) is adapted to measure an exhaust gas temperature. Device according to one of Claims 5 to 7 , characterized in that a measuring device (33) is adapted to measure a temperature of an exhaust pipe (21, 22) which is at least indirectly connected to the storage catalytic converter (23). Device according to one of Claims 5 to 8th , characterized in that a measuring device (32) is adapted to measure a temperature of the diesel engine (10). Device according to one of the preceding claims, characterized in that it is set up to detect and store operating data of the diesel engine (10), wherein the control unit (30) is adapted to detect the low-temperature control based on stored operating data.

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