DE102014209316A1 - Method and control device for carrying out exhaust gas-relevant diagnoses - Google Patents

Abstract

The present invention relates to a method (6) for carrying out exhaust-related diagnoses in a vehicle having an internal combustion engine having a plurality of cylinders, of which one or more cylinders are switched off, wherein the internal combustion engine performs load-dependent different operating modes, which are in a number of disabled cylinders from each other differ. According to the method, an operation mode that is preferable for performing a diagnosis is determined (60).

Description

The invention relates to a method and a control device for carrying out exhaust-related diagnoses for a vehicle with an internal combustion engine, which uses a cylinder deactivation.

Cylinder deactivation is used on vehicles with internal combustion engines to reduce fuel consumption and pollutant emissions of the internal combustion engine. The internal combustion engine has a plurality of cylinders, which may for example be distributed over two cylinder banks. During cylinder deactivation, selected cylinders, for example the cylinders of a cylinder bank, are switched off or reconnected depending on the engine load and / or the requested torque during operation of the internal combustion engine.

Like from the DE 10 2010 033 606 A1 As can be seen, the cylinder deactivation can continue to be controlled in dependence on the road gradient. For this purpose, the gradient of a lane ahead of the vehicle is determined. Depending on the gradient individual cylinders are then switched off or on.

In addition to the cylinder deactivation, however, it is also necessary to carry out a series of exhaust gas-relevant diagnoses in the context of an on-board diagnosis, in order to ensure that the pollutant emission of the internal combustion engine does not exceed legally prescribed threshold values. For example, diagnoses of lambda probes or catalyst diagnoses are counted among these diagnoses. However, these can only be carried out successfully under certain diagnostic conditions, so that a shutdown or connection of cylinders interferes with an ongoing diagnosis or even forces it to prematurely abort. For example, a catalyst diagnosis can only be carried out at a clearly defined exhaust gas mass flow, which is achieved only in an operating mode in which all the cylinders are switched on, ie in full engine operation. Therefore, if one switches to full engine operation and dispenses with a cylinder deactivation during the catalyst diagnosis, this leads to an increase in CO ₂ emissions.

It is therefore an object of the present invention to provide a method and a control device for executing exhaust gas-relevant diagnoses, which utilize the advantages of cylinder deactivation even during the execution of exhaust gas-relevant diagnoses.

This object is achieved by the method according to the invention for executing exhaust gas-relevant diagnoses according to claim 1 and the control device for executing exhaust gas-relevant diagnoses according to claim 10.

According to one aspect, the present invention relates to a method for carrying out exhaust-related diagnoses in an internal combustion engine having a plurality of cylinders, of which one or more cylinders are switched off, wherein the internal combustion engine performs load-dependent different operating modes, which are in a number of deactivated cylinders from each other wherein an operating mode that is preferred for performing a diagnosis is determined.

According to a further aspect of the present invention, a control device for carrying out exhaust-related diagnoses for a vehicle having an internal combustion engine, which has a plurality of cylinders, of which one or more cylinders are switched off, wherein the internal combustion engine is load-dependent operable in different operating modes, which in number disconnected cylinders, in particular for carrying out a method according to the previous aspect, a diagnostic module for determining an operating mode, which is preferred for performing a diagnosis.

Further advantageous embodiments of the invention will become apparent from the subclaims and the following description of preferred embodiments of the present invention.

A method according to the invention for carrying out exhaust gas-relevant diagnoses for a vehicle is based on an embodiment of the internal combustion engine in which a plurality of cylinders, for example 4, 5, 6, 8, 10, 12, 16 cylinders are provided, of which one or more cylinders can be switched off. From a deactivated cylinder, for example, if in the cylinder for one or more cycles of the internal combustion engine an injection suppression takes place, ie no fuel is injected, so that the cylinder does not contribute substantially to the performance of the internal combustion engine. A deactivated cylinder may also be present if, in addition to or as an alternative to injection suppression, supply of fresh air and discharge of residual gas to and from a combustion space cooperating with the cylinder is suspended by closing an intake valve and an exhaust valve for one or more cycles of the internal combustion engine becomes. The internal combustion engine on which the method according to the invention is based carries out different operating modes as a function of the engine load, which differ from one another in a number of deactivated cylinders. Examples of typical operating modes Internal combustion engine in which the cylinders are distributed on two engine banks are a full engine operation, in which all cylinders are switched on, a half-engine operation on a first bank (master bank), in which all cylinders of the first bank are switched on and all cylinders of the second bank (Slavebank ) and a half-engine operation on the second bank, in which all the cylinders of the first bank are switched off and all the cylinders of the second bank are switched on. In some embodiments, however, operating modes may also be considered in which individual selected cylinders are switched off.

According to the method of the invention, an operating mode that is preferred for performing a diagnosis is determined. For example, an operating mode can be determined in which the diagnosis can not only be carried out, but in which the diagnosis can also be successfully ended with a high probability. The method according to the invention thus makes it possible for the preferred operating mode for the diagnosis to be applied freely and for an active request of the preferred operating mode to be carried out by means of a ready-to-run diagnosis.

The diagnosis can be, for example, a dynamic diagnosis of lambda probes arranged between the combustion chamber and a catalytic converter, a plausibility diagnosis of these lambda probes, a dynamic diagnosis of lambda probes arranged on a side of the catalytic converter facing away from the combustion chamber, or a catalyst diagnosis or other diagnosis relevant to the exhaust gas. For carrying out these diagnoses, it may be important, for example, for an exhaust gas mass flow and a temperature of the lambda probes or of the catalytic converter to be within a certain range. For the diagnostic conditions of the catalyst diagnosis, e.g. the conditions include that a rotational speed of the internal combustion engine is in a range of 1000 rpm to 3200 rpm, a heat amount carried in the catalyst is in a range of 400 kJ and 3000 kJ, a relative load is 15% to 70% % is that a catalyst temperature for 0 to 60 s or longer in the range of 400 ° C to 800 ° C, that the exhaust gas mass flow 20 kg / h to 70 kg / h and / or that a temperature gradient in the catalyst max. 60 ° C. Diagnoses may be made once per drive cycle of the vehicle, wherein a drive cycle in some embodiments may be a test cycle or a period of time from startup to directly subsequent shutdown of the internal combustion engine by a user. For long uninterrupted engine runtimes, diagnostics may be performed more frequently than once per drive cycle if necessary.

It is also possible to provide several emissions-relevant diagnoses for execution. These can each have a diagnostic priority that determines an order according to which the diagnoses are to be processed, provided that their execution is possible under the current conditions and the diagnoses must not be executed simultaneously. The diagnostic priority may depend on how long the diagnosis has not been performed, or if the diagnosis is in progress, or other factors.

In determining the preferred mode of operation, each mode of operation may be assigned a mode priority. On this basis, it can be determined to which operation mode the largest mode priority is assigned, and it is determined that the operation mode whose mode priority is the largest is the preferred operation mode. The preferred operating mode of a diagnosis can thus be determined by simple assignment and evaluation of mode priorities.

In determining the preferred mode of operation, prediction can be used to determine operating variables of the vehicle in an operating mode. On this basis, it can be determined for this operating mode whether the predicted operating variables of the vehicle fulfill diagnostic conditions for carrying out the diagnosis. In order to determine whether the diagnostic conditions in the operating mode are met, the expected operating variables of the vehicle in the operating mode can be compared with corresponding diagnostic conditions, the diagnostic conditions being considered to be satisfied in accordance with the expected operating variables. Thereafter, the mode priority of this mode of operation may be set depending on whether the predicted operational quantities satisfy the diagnostic conditions. The set mode priority may then be assigned to this mode of operation as mode priority.

In this way, expected operating variables of the vehicle in an operating mode can be estimated or calculated in a forward-looking manner in order then to be able to determine the preferred operating mode from the comparison of the estimated or calculated operating variables with the diagnostic conditions that represent runtime conditions for the diagnosis and the mode priority derived therefrom ,

The operating variables of the vehicle can be, for example, operating variables of the internal combustion engine, for example the mass flow or the rotational speed of the internal combustion engine, or state variables of individual components, eg the temperature in the combustion chamber, the temperature of the lambda probes or the temperature of the catalytic converter. be counted. The diagnostic conditions may relate to the operating variables of the vehicle, in particular operating variables of the internal combustion engine and / or state variables of selected components of the vehicle, and may represent threshold values or threshold ranges for the operating variables of the internal combustion engine or for the state variables of the various components of the internal combustion engine.

Furthermore, the expected operating variables of the vehicle in one or more further operating modes can be determined for one or more further operating modes by prediction. It can thus be determined whether the diagnostic conditions in the one or more operating modes are met, for which one or more modes of operation a mode priority is set and the mode priority is assigned to this or these modes of operation.

Setting the mode priority of one or more modes of operation may include setting a base priority that, when the predicted operating variables of the internal combustion engine meet the diagnostic conditions, is supplemented by a mode markup. The mode premium may be, for example, a multiplication of a fixed premium with a weighting factor. Thus, an operation mode in which the predicted operation amounts of the vehicle do not satisfy the diagnosis conditions may be assigned the base priority as a mode priority and an operation mode in which the predicted operation amounts satisfy the diagnosis conditions, the base priority added as the mode priority may be assigned the mode premium. To ensure that only one mode of operation is detected as the preferred mode of operation, the base priorities and / or mode surcharges may differ for different modes of operation.

If the diagnostic conditions of a diagnosis are fulfilled only in one operating mode, this can be assigned the highest mode priority. If the diagnostic conditions are not fulfilled in any operating mode, it may be continued to predetermine the expected operating variables of the vehicle by prediction and to compare them with the diagnostic conditions until the diagnostic conditions in at least one operating mode are met.

The prediction of the expected operating variables of the vehicle in an operating mode can be achieved, for example, by simulating the expected operating variables for the operating mode and / or reading out the expected operating variables for the operating mode, for example from characteristic maps or characteristic curves. Thus, e.g. the expected exhaust gas mass flow can be determined with foresight. For some of the operating variables of the vehicle, for example for the temperatures of the components, it may be sufficient in some embodiments to assume actually measured values as expected operating variables, since they only change slowly and can be assumed to be stable for the duration of the operation Change the diagnosis only slightly so that the diagnosis can be successfully completed.

If it is to be determined whether the operating variables of the vehicle for the current operating mode fulfill the diagnostic conditions, initially measured values or values calculated from these can be compared with the diagnostic conditions. If the actual measured values or the values calculated therefrom do not correspond to the diagnostic conditions, it can be concluded that the diagnosis can not be performed in the current operating mode and the current operating mode is not the preferred operating mode. If, however, the actual measured values or the values calculated therefrom correspond to the diagnostic conditions, additionally expected operating variables can be determined by prediction in order to determine whether the diagnostic conditions will also be fulfilled for the duration of the diagnosis.

Determining the preferred mode of operation may be performed for a first diagnosis and for a second diagnosis. In some embodiments, the first and second diagnoses are diagnoses that may not be made in parallel so as not to interfere with each other. To determine the preferred operating mode of the first and second diagnoses, the first diagnosis may be assigned a first prediction priority and the second diagnosis may be assigned a second prediction priority. The assignment of a prediction priority can also be carried out for further diagnoses in some embodiments. After assigning the prediction priority, it can be determined which diagnosis is assigned the largest prediction priority. Based on the result of which diagnosis is assigned the largest prediction priority, then the mode priority of the modes of operation for different diagnoses can be set. For example, if the first diagnostic is assigned the highest prediction priority, the modes of operation in which the first diagnostic can be performed can be assigned as mode priority the basic priorities supplemented with the mode surcharge. On the other hand, the operating modes of the second diagnosis may be assigned the basic priorities without the mode surcharge as the mode priority, even if the second diagnosis could be performed in the operating modes. This can be clearly determined which Operation mode for the first diagnosis to be performed as a priority, which is the preferred operating mode.

Setting the prediction priority of the first diagnosis may be similar to setting the mode priority. In some embodiments, a basic priority may be set thereto which, when the diagnostic conditions of the first diagnosis for one or more modes of operation are met, is supplemented with a prediction premium. The mode premium may be, for example, a multiplication of a fixed premium with a weighting factor. In a corresponding manner, the prediction priority for the second and possibly further diagnoses can also be set.

The method for carrying out exhaust-related diagnoses may further include, for example, checking, at the beginning of the method, for example, whether the cylinder deactivation, which may be designed, for example, as soft bank deactivation, is active. In some embodiments, this is the case when the internal combustion engine is in a s.g. Default mode is operated by automatically switching between the full engine operation and the half-engine operation on the first bank or on the second bank. In some embodiments, a cylinder deactivation may be activated when the temperature of the internal combustion engine reaches a threshold temperature, e.g. 42 ° C exceeds when the internal combustion engine in a high gear, for example in one of the gear stages 5 to 8 runs, when the vehicle speed, a threshold speed, e.g. 28 km / h, when the catalyst does not need to be heated and / or when an engine speed in a threshold range, e.g. ranging from 750 rpm to 3000 rpm. During the period in which no diagnosis is running, the operating modes can be requested by cylinder deactivation. A diagnosis can thus actively switch between the operating modes, for example, full engine operation and half engine operation on different banks, when the above-mentioned conditions for the cylinder deactivation are met.

One or more diagnoses may include an identifier that is changed depending on a status of the diagnosis. In accordance with the method for performing emissions-related diagnostics, the tag may be periodically inspected to determine the status of the diagnostic and to take further action, such as adjusting the diagnostic priority, or preventing it from occurring, for example, to prevent one second diagnosis starts, although the first diagnosis should start as a priority. For example, the tag may have a series of bits that are set when, for example, the tagged diagnostic is executed or disabled because it may not be executed in conjunction with a second diagnostic because their results would interfere with each other.

The designation of a current or active diagnosis can also specify in some embodiments that a change in the operating mode is only permissible if the diagnostic conditions for the current diagnosis are also fulfilled in this operating mode and a corresponding release has been issued. As long as the diagnosis is running, an operating mode change can only take place if this is enabled by the diagnosis.

The method for executing emissions-related diagnostics may further include requesting the preferred operating mode via a mode coordinator of a motor controller. For this purpose, as a result of determining the preferred operating mode, a signal for controlling the cylinders or the cylinder banks can be generated in accordance with the preferred operating mode. Similarly, if no diagnostics are in progress and / or no diagnostics request a particular operating mode, a signal to control the cylinders or cylinder banks may be generated based on the automatic cylinder deactivation in default mode.

After requesting the preferred operating mode or after setting the preferred operating mode, for example based on the generated signal for controlling the cylinders or the cylinder banks, the diagnosis can be started in the requested operating mode. After the diagnosis has been successfully completed, the diagnosis can be ended. In some embodiments, termination of the diagnostic may be indicated by the tag. Alternatively or additionally, the diagnosis priority of the diagnosis can be reduced after termination of the diagnosis.

In order to be able to exploit the effects of cylinder deactivation on fuel consumption and pollutant emission during an ongoing diagnosis, it may be necessary to switch to an operating mode requested by the cylinder deactivation, which however requires a release by the diagnosis. In order to make this release available, expected operating variables in different operating modes or in the operating mode requested by the cylinder deactivation can be predicted during diagnosis and compared with the diagnostic conditions. If the diagnostic conditions are met by the predicted operating variables of the operating mode requested by the cylinder deactivation, a release can be issued. Otherwise, a change of operating mode is prevented. For a catalyst diagnosis, for example, in full engine operation an exhaust gas mass flow of at least 23 kg / h is necessary. Runs the catalyst diagnosis in half-engine operation at an exhaust gas mass flow of, for example, 40 kg / h and is requested by the cylinder deactivation operating mode change to full engine operation, the release can be denied because the exhaust mass would be distributed over two banks and the exhaust gas mass flow per bank only 20 kg / h would be and the diagnostic conditions in full engine operation are not met.

To successfully perform some diagnostics, such as catalyst diagnostics, in semi-engine operation, it may be necessary for the diagnostics to be run first in half engine operation of the first bank and then in half engine operation of the second bank. It may thus be necessary to change the operating mode. Therefore, according to the method of executing exhaust-related diagnoses, after the diagnosis is started while it is running, whether the diagnostic conditions in different operation modes are satisfied, whether the requested operation mode for the diagnosis is still the preferred operation mode and another operation mode can be monitored be requested if the current operating mode is not the preferred operating mode. For the catalyst diagnosis described in the preceding paragraph, this may mean that once the catalyst diagnosis on the first bank has ended, the preferred mode of operation may again be determined and, for example, a half engine operation on the second bank, i. a bank change, can be requested, since in a bank change the mass flow of 40 kg / h is maintained.

There is thus the possibility that the preferred operating mode is specifically determined by the diagnosis and is subsequently requested. In addition, it can be ensured that the active cylinder deactivation is optimally utilized even until the end of the diagnosis.

The present invention further relates to a control device for carrying out exhaust gas-relevant diagnoses for a vehicle having an internal combustion engine, in particular for carrying out the method according to the invention with the features described above. The control device is designed for an internal combustion engine having a plurality of cylinders, one or more cylinders of which can be switched off. The internal combustion engine is load-dependent operable in different operating modes, which differ from one another in a number of deactivated cylinders. The control device is designed to determine an operating mode which is preferred for carrying out a diagnosis and contains a diagnostic module and a diagnostic planner.

The control device may be designed to perform the method steps mentioned with regard to the above-described method individually or in any desired combinations. The above-described method according to the invention for carrying out exhaust gas-relevant diagnoses when using the cylinder deactivation can be implemented as a computer program. The computer program can for example be stored on a storage medium and be executable with the aid of the control device. The control device may, for example, contain electronic components, e.g. a processor and / or an electronic data storage. The diagnostic module and the diagnostic scheduler may be implemented in software.

In some embodiments, the diagnostic module may be configured to determine, by prediction, expected operating quantities of the vehicle in an operating mode, compare them to diagnostic conditions of the diagnosis, and assign a mode priority to that operating mode based on the comparison.

The diagnostic scheduler may be configured to analyze the mode priorities of various modes of operation and to identify the mode mode with the highest mode priority as the preferred mode of operation. The diagnostic scheduler may also be configured to request the preferred mode of operation from a mode coordinator and to release the diagnostic.

The control device may comprise a further diagnostic module, which is designed essentially like the diagnostic module described above. Both diagnostic modules can also be designed to assign a respective prediction priority to the respective diagnosis, which is increased if the respective diagnosis can be carried out at least in one operating mode. The diagnostic scheduler may be configured to determine, based on the prediction priority of each diagnosis, that only the diagnostic module of the highest prediction priority diagnostic assigns mode priorities that reflect the result of the comparison of the predicted operational quantities with the diagnostic conditions, eg, are increased when the diagnostic conditions are fulfilled.

The control device may e.g. be integrated into a diagnostic sequence control.

Some embodiments also relate to a motor vehicle having an internal combustion engine and a control device as described above. The vehicle may be a hybrid vehicle in some embodiments.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

1 represents a table with examples of diagnostic priorities;

2 a schematic representation of an embodiment of a control device shows;

3 shows a table with examples of mode priorities;

4 represents a table with examples of prediction priorities; and

5 a schematic representation of an embodiment of a method according to the invention shows.

As mentioned in the introduction, vehicles today have to meet legal requirements. In order to meet these legal requirements, it is necessary to carry out different exhaust-related diagnoses under certain conditions, which can only be successfully carried out at certain temperatures, mass flows, load ranges, speeds and other conditions. For carrying out and coordinating the diagnoses, a diagnostic sequence control is used, which is formed from different modules. An important module is the so-called diagnostic planner, which among other things coordinates the different diagnoses, as later with reference to 2 will be explained.

For each diagnostic, there is an identifier that contains a series of bits to indicate a status of the diagnosis. In this case, e.g. each indicate a particular set bit that not all diagnostic conditions are met, that the diagnosis is currently running, that the diagnosis is disabled due to expected collisions with another diagnosis, that the diagnosis is ready and waiting for a release or all Conditions for starting the diagnosis are met.

The sequence of the different diagnoses is controlled by the diagnostic sequencer based on a diagnostic priority that is assigned to each diagnosis and that is adjusted. The diagnostic priority will be with reference to 1 described a table 20 with examples of the diagnosis priority. In the left column 201 of the 1 are diagnostic priority labels (Prio_Diagnose_x) 203 listed for different diagnoses. Prio_Diagnose_1 is the diagnostic priority of a dynamic diagnosis of lambda probes arranged in front of a catalytic converter, Prio_Diagnose_2 the diagnostic priority of a plausibility diagnosis of these lambda probes, Prio_Diagnose_3a and Prio_Diagnose_3b the diagnostic priorities of a dynamic diagnosis of lambda probes arranged downstream of the catalytic converter, and Prio_Diagnose_4a and Prio_Diagnose_4b designates the diagnostic priorities of a catalyst diagnosis. To each diagnostic priority label 203 shows the second column 205 from the left a basic priority 207 which is 3700 for the diagnosis Prio_Diagnose_4b, for example. In the third column 209 from the left is a surcharge 211 displayed. This becomes the base priority 207 added depending on certain conditions. The addition depends, among other things, on whether the diagnostic conditions are met, how urgently the diagnosis is to be carried out and whether the diagnosis is already running. If, for example, the diagnosis Prio_Diagnose_4b has been started, the surcharge will be awarded 211 in the amount of 500 to the base priority 207 added. The other diagnoses receive no surcharge or possibly a lower surcharge. In the fourth column 213 from the left is the adjusted or dynamic diagnostic priority 215 for each diagnosis in the event that this diagnosis is being performed listed. The diagnosis Prio_Diagnose_4b results in a dynamic diagnosis priority 215 in the amount of 4200.

Depending on the diagnostic tagging and the adjusted diagnostic priorities, the diagnostic sequencing controller determines which of the diagnostics will be executed.

When carrying out the different diagnoses, the operating mode also plays an essential role. In the present example, an internal combustion engine is designed as a V-type engine and contains a plurality of cylinders, for example 12 cylinders. Each six of the cylinders are arranged in a row and form a cylinder bank. The internal combustion engine may perform different modes of operation by having all cylinders active (full engine mode - VMB), or the cylinders of one bank (half motor mode on one bank - HMBM) or the other bank (half motor mode on the other bank - HMBS) are off. Depending on the speed and instantaneous request, suitable operating modes can then be carried out.

2 schematically shows an embodiment of a control device according to the invention 3 or a computer program. The control device 3 contains a number of diagnostic modules 30a . 30b . 30c . 30d , a mode coordinator 31 and a diagnostic planner 32 , The mode coordinator 31 is designed to control signals 3101 . 3103 to generate and send to regulators of the actuators of the internal combustion engine to a certain operating mode of the operating modes VMB 331 , HMBM 333 and HMBS 335 adjust. In addition, the mode coordinator is 31 adapted to a mode of operation of the operating modes VMB 331 , HMBM 333 and HMBS 335 in which the fuel consumption is minimal, for example, to determine and make a request 3105 to the diagnostics planner 32 output whether the particular operating mode may be set.

The diagnostic planner 32 is trained to the request 3105 of the mode coordinator 31 with a release 3201 to respond or another mode of operation by a request signal 3203 requesting and requesting the diagnostic modules 30a . 30b . 30c . 30d considered as explained below.

Each diagnostic module 30a . 30b . 30c . 30d is intended to manage one diagnosis at a time. Each diagnostic module has a prediction device 301 on, which is adapted to determine on the basis of state variables of the internal combustion engine, eg mass flows, temperatures, torque releases, etc., using a prediction, whether and in which operating modes by the diagnostic module 30a to be managed diagnosis can be performed. If the prediction device 301 determines that the diagnosis diagnostic conditions for one or more modes of operation 331 . 333 . 335 are met, the diagnostic module gives this in a signal 3001 to the diagnostics planner 32 out. The signal 3001 Also includes an up-to-date tag of the diagnosis and a diagnostic priority as related to 1 has been described. The signal 3001 contains information about which diagnostics are executed. In addition, the prediction device generates 301 a prediction signal 3003 indicating in which operating mode 331 . 333 . 335 the diagnosis can be carried out.

In addition, each diagnostic module contains 30a . 30b . 30c . 30d a prediction priority determination unit 303 , This determines on the basis of the prediction signal 3003 a prediction priority 3005 , In 3 is a table 40 showing an example of a prediction priority 3005 shown.

In the left column 401 are prediction priority names for different diagnoses (Diagnose_x_Prdn) 403 listed. Diagnosis_1_Prdn is the prediction priority of a dynamic diagnosis of lambda probes, which are arranged in front of a catalytic converter, Diagnose_2_Prdn is the prediction priority of a plausibility diagnosis of these lambda probes, Diangose_3_Prdn is the prediction priority of a dynamic diagnosis of lambda probes arranged downstream of the catalytic converter, and Diangose_4_Prdn is the prediction priority of a catalyst diagnosis designated. For each prediction priority designation 403 shows the second column 405 from the left a basic priority 407 for example, for which the prediction priority designation is Diagnosis_4_Prdn 2500. In the third column 409 from the left is a firm serve 411 displayed. This one comes with a weighting factor 413 in the fourth column 415 is displayed from the left, multiplied and as a prediction premium to the base priority 407 added when the prediction signal 3003 the information includes that the diagnosis can be performed in one or more modes of operation. In the fifth column 417 from the left is the adjusted or dynamic prediction priority 419 for each prediction priority designation 403 or every diagnosis listed. For the diagnosis Diagnosis_4_Prdn a dynamic prediction priority results 419 in the amount of 4500. The prediction priority 3005 coming from the diagnostic module 30a to the diagnostics planner 32 is the base priority 407 from column 405 be if the diagnosis in any of the operating modes 331 . 333 . 335 or the dynamic prediction priority 419 from column 417 if the diagnosis is in one or more modes of operation 331 . 333 . 335 can be executed.

The diagnostic planner 32 compares those from the diagnostic module 30a received prediction priority 3005 with prediction priorities that it receives from the other diagnostic modules 30b . 30c . 30d receives, and generates a release signal 3205 that he sent to the diagnostic module 30a transmitted when the prediction priority 3005 is greater than the other diagnostic modules 30b . 30c . 30d transmitted prediction priorities.

The diagnostic module 30a also contains a selector 305 that the release signal 3205 and the prediction signal 3003 receives. Once the release signal 3205 is received, represents the selection device 305 based on the prediction signal 3003 determines in which or in which operating modes the diagnosis can be performed. Each operating mode 331 . 333 . 335 becomes a mode priority 3007 assigned by the selector 305 depending on the prediction signal 3003 can be adjusted.

4 shows a table 50 , which is an example of a mode priority 3007 shown.

In the left column 501 are mode priority labels for different modes of operation (mode_x) 503 listed. Mode_DEF is the mode priority of a default mode, switching between full motor and half motor on both banks as required, Mode_VMB mode priority of full motor mode, Mode_HMBM mode priority of half motor operation on one bank and Mode_HMBS mode priority of half motor operation on the other Bank designates. The default mode is the Mode in which cylinder deactivation is used independently of diagnostics. To each mode priority label 503 shows the second column 505 from the left a basic priority 507 for example, for which the mode priority designation is Modus_HMBS 1800. In the third column 509 from the left is a firm serve 511 displayed. This one comes with a weighting factor 513 in the fourth column 515 from the left, multiplied and as a mode premium to the base priority 507 added when the prediction signal 3003 contains the information that the diagnosis can be performed in the respective operating mode. In the fifth column 517 from the left is the adjusted or dynamic mode priority 519 for each mode priority label 403 or each operating mode is listed. Mode_HMBS mode has a dynamic mode priority 519 in the amount of 2800.

Can the selection device 305 in 2 the prediction signal 3003 For example, assume that the diagnosis can be performed in the operating modes HMBM and HMBS, the default mode and the VMB as mode priority Modus_DEF and Modus_VMB the basic priority in column 505 , ie assigned to 2000 or 1900, respectively, and the operating modes HMBM and HMBS as mode priorities Mode_HMBM and Mode_HMBS the dynamic mode priority in column 517 , so 2700 or 2800 is assigned. The mode priority 3007 is thus the basic priority 507 from column 505 if the diagnosis can not be performed in the respective operating mode or the dynamic diagnosis priority 519 from column 517 if the diagnosis can be performed in the respective operating mode.

The mode priorities 3007 are in a mode priority signal 3009 to the diagnostics planner 32 transmitted. This compares the mode priorities 3007 and determines the operating mode 331 . 333 . 335 , which is the highest mode priority 3007 has. In the example according to which the diagnosis can be carried out in the operating modes HMBM and HMBS, the diagnostic scheduler determines 32 in that the operating mode HMBS is the highest mode priority 519 (2800). As a result the diagnostic planner asks 32 via the request signal 3203 the operating mode with the highest mode priority, here HMBS, and the mode coordinator generates and transmits corresponding control signals 3101 . 3103 ,

5 shows a flowchart of the method according to the invention 6 for performing a diagnosis, such as a catalyst diagnosis.

On the basis of operating variables of the internal combustion engine, for example on the basis of mass flows, temperatures etc., is checked ( 600 ), whether a cylinder deactivation is possible, ie whether a default mode is executed. If a cylinder deactivation is possible, is via a start signal 6000 for each operating mode VMB, HMBM and HMBS a prediction process is initiated 601 . 601b . 601c , In addition, it is determined 601 whether the catalyst diagnosis can be carried out in full engine operation VMB. If the catalyst diagnosis according to the prediction result in full engine operation VMB can be performed, a prediction signal 6003a generated, which contains a corresponding information. In a similar way is determined 601b . 601c whether the catalyst diagnosis can be carried out in the two half-motor operations HMBM and HMBS, and if so, a prediction signal 6003b respectively. 6003c generated.

The catalyst diagnosis is a prediction priority 6005 assigned 603 , If one of the prediction signals 6003a . 6003b . 6003c indicates that the catalyst diagnosis can be carried out in one of the operating modes VMB, HMBM or HMBS, the prediction priority is established 6005 from the base priority 407 in 4 and the prediction markup together. The prediction priority 6005 is compared with prediction priorities of other diagnoses 604 , If the prediction priority of the catalyst diagnosis is greater than the prediction priorities of the other diagnoses, a release signal will continue to be generated 6205 generated 604 ,

Subsequently, based on the prediction signal 6003 and the enable signal 6205 the full engine operation VMB a mode priority 6009a assigned 605a , If it can be seen from the prediction signal that the catalyst diagnosis can be carried out in the full-engine operation VMB, and is released by the release signal 6205 before, the mode priority becomes the base priority 507 in 4 and the mode surcharge. Otherwise, the mode priority is the same 6009a the basic priority 507 , Accordingly, the two half-motor operations HMBM or HMBS becomes a mode priority 6009b respectively. 6009c assigned 605b . 605c ,

The mode priorities 6007A . 6007b . 6007c compared to each other and the operating mode, which is the highest mode priority 6007A . 6007b . 6007c is assigned is selected and requested 606 ,

The process steps 601 . 601b . 601c . 603 . 604 . 605a . 605b . 605c and 606 can become a general process step 60 as determining an operating mode that is preferred for performing a diagnosis.

LIST OF REFERENCE NUMBERS

20

Diagnostic Priority Table

201

first column from the left

203

Diagnosis priority name

205

second column from the left

207

Basic Priority of Diagnostic Priority

209

third column from the left

211

surcharge

213

fourth column from the left

215

dynamic diagnostic priority

3

control device

30a, 30b, 30c, 30d

diagnostic modules

301

prediction

303

Prädiktionsprioritätsbestimmungseinheit

305

selector

3001

signal

3003

prediction

3005

Prädiktionspriorität

3007

mode priority

3009

Mode priority signal

31

Modes Coordinator

3101, 3103

control signals

3105

Request if certain operating mode may be executed

32

diagnosis planners

3201

Release signal in response to request 3105

3203

request signal

3205

enable signal

331

Full Engine

333

Half engine operation on a bench

335

Half engine operation on another bank

40

Table on prediction priority

401

left column

403

Prädiktionsprioritätsbezeichnung

405

second column from the left

407

Basic priority of the prediction priority

409

third column from the left

411

firm serve

413

Weighting factor of the prediction priority

415

fourth column from the left

417

fifth column from the left

419

dynamic prediction priority

50

Table to Mode Priority

501

left column

503

Mode Priority Designation

505

second column from the left

507

Basic priority of mode priority

509

third column from the left

511

firm serve

513

Weighting factor of the mode priority

515

fourth column from the left

517

fifth column from the left

519

dynamic mode priority

6

Method for performing a diagnosis

60

Determining a preferred operating mode

600

Determine if cylinder deactivation is possible

601a, 601b, 601c

Determine if diagnostics can be performed in operating modes

603

Assign a prediction priority

605

Determine if a release is possible

605a, 605b, 605c

Assign mode priorities

606

Requesting an operating mode

6000

start signal

6003a, 6003b, 6003c

prediction

6005

Prädiktionspriorität

6007a, 6007b, 6007c

mode priorities

6205

enable signal

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

• DE 102010033606 A1 [0003]

Claims (10)

Method for carrying out exhaust gas-relevant diagnoses in a vehicle having an internal combustion engine, which has a plurality of cylinders, of which one or more cylinders can be switched off, wherein the internal combustion engine determines different operating modes depending on the load ( 331 . 333 . 335 ), which differ in a number of deactivated cylinders, an operating mode which is preferred for carrying out a diagnosis is determined ( 60 ). Method according to the preceding claim, wherein said determining ( 60 ) of the preferred operating mode comprises: assigning ( 605a . 605b . 605c ) one mode priority to each mode of operation ( 331 . 333 . 335 ); Determine ( 606 ) to which operating mode the highest mode priority is assigned; and determining ( 606 ) that the mode of operation whose mode priority is the largest is the preferred mode of operation. Method according to the preceding claim, wherein said determining ( 60 ) of the preferred mode of operation further comprises: determining ( 601 . 601b . 601c ) of operating quantities of the vehicle in an operation mode by prediction; Determine ( 601 . 601b . 601c for this mode of operation, whether the predicted operational quantities of the vehicle meet diagnostic conditions for performing the diagnosis; and setting the mode priority of this mode of operation as a function of ( 6003a . 6003b . 6003c ), whether the predicted operating variables meet the diagnostic conditions. The method of the preceding claim, wherein setting the mode priority of the operating mode comprises: setting a base priority ( 507 ), which, when the predicted operating variables meet the diagnostic conditions, is supplemented by a mode markup. Method according to one of claims 3 or 4, wherein the determining ( 601 . 601b . 601c ) of the operating variables contains by prediction a simulation of the expected operating variables for the operating mode and / or a reading of the expected operating variables for the operating mode. Method according to one of claims 2 to 5, wherein said determining ( 60 ) of the preferred operating mode for a first diagnosis and for a second diagnosis, wherein the determining ( 60 ) of the preferred operating mode for the first diagnosis and for the second diagnosis further comprises: assigning ( 603 ) a first prediction priority to the first diagnosis and assigning a second prediction priority to the second diagnosis; Determine ( 604 ), to which diagnosis the largest prediction priority is assigned; and setting the mode priority of the operating mode in dependence thereon ( 6205 ), which diagnosis is assigned the largest prediction priority. The method of the preceding claim, wherein setting the prediction priority of the first diagnosis comprises: setting a base priority ( 407 ) which, when the diagnostic conditions of the first diagnosis for one or more modes of operation are met, is supplemented by a prediction premium.  The method of any one of the preceding claims, wherein the diagnostic includes an identifier that is changed depending on a status of the diagnosis. The method of any one of the preceding claims, the method further comprising: requesting the preferred mode of operation ( 606 ). Control device for carrying out exhaust-related diagnoses for an internal combustion engine having a plurality of cylinders, of which one or more cylinders are switched off, wherein the internal combustion engine is load-dependent operable in different operating modes, which differ from one another in a number of deactivated cylinders, in particular for carrying out a Procedure ( 6 ) according to one of the preceding claims, wherein the control device ( 3 ) is configured to determine an operating mode that is preferred for performing a diagnosis, and a diagnostic module ( 30 ) and a diagnostic planner ( 32 ) contains.

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