DE102016225780A1 - Method and device for operating an engine system of a motor vehicle - Google Patents

Abstract

The invention relates to a method for operating an engine system (1), wherein the engine system (1) comprises a number of components that are monitored and / or adapted and / or regenerated by means of a plurality of special functions, comprising the following steps: - providing (S2) Cost functions indicating a course of a cost value based on an operating parameter of the engine system (1) for the plurality of special functions; - providing (S3) a predicted time history of the operating parameter over a most probable travel distance, - combining (S4) the cost functions respectively with the predicted temporal course of the operating parameter to obtain a temporal cost course for each of the several special functions - creating (S8) a scheduling based on the temporal cost curves for each of the special functions - executing the special functions according to the created scheduling.

Description

Technical background

In addition to the conventional operation of a motor vehicle, various special functions must be performed temporarily. The special functions take into account the diagnosis of sensors, actuators and subsystems of the motor system and are intended to ensure the continuous functioning of components. These special functions include, for example, a catalyst regeneration function, a particulate filter cleaning function, or a function for diagnosing and / or adapting a throttle plate actuator, and the like. According to the specification, the special functions are to be executed within specified periods, regularly, periodically or at predetermined times.

Since the special functions are often competing, i. can not be executed simultaneously, a priority order is given for them, so that when simultaneously requesting the execution of a special function, the higher priority according to the priority order selected special function for execution. Since various special functions require special operating conditions, they can only be carried out under certain driving conditions or operating points of the engine system taken separately.

However, since separately occupied operating points often affect the efficiency of the operation of the engine system, it is desirable to wait during operation of the engine system for a time when there is a favorable for the upcoming special function operating point of the engine system. However, this does not guarantee that the operating state required for this execution of the special function is sufficiently long to successfully complete a started execution of the special function.

Since special functions can reduce the efficiency of the engine system, particularly in terms of energy consumption, pollutant emissions, and the like, frequent crashes in the execution of the special functions significantly affect the performance of the engine system.

Disclosure of the invention

According to the invention, a method for operating an engine system according to claim 1 as well as an apparatus and the engine system according to the independent claims are provided.

Further embodiments are specified in the dependent claims.

• - Bereitstellen von Kostenfunktionen, die einen Verlauf eines Kostenwerts basierend auf einem Betriebsparameter des Motorsystems angeben, für die mehreren Sonderfunktionen;
• - Bereitstellen eines prädizierten zeitlichen Verlaufs des Betriebsparameters über eine am wahrscheinlichsten zu befahrende Fahrstrecke;
• - Kombinieren der Kostenfunktion mit dem prädizierten zeitlichen Verlauf des Betriebsparameters, um einen zeitlichen Kostenverlauf für jede der mehreren Sonderfunktionen zu erhalten;
• - Erstellen einer Ablaufplanung basierend auf den zeitlichen Kostenverläufen für jede der Sonderfunktionen;
• - Ausführen der Sonderfunktionen gemäß der erstellten Ablaufplanung.

According to a first aspect, there is provided a method of operating an engine system, the engine system including a number of components that are monitored and / or adapted and / or regenerated using a plurality of special functions, comprising the steps of:

• Providing cost functions indicative of a history of a cost value based on an operating parameter of the engine system for the plurality of special functions;
• - Providing a predicted time profile of the operating parameter on a most likely to be traveled route;
• Combining the cost function with the predicted time history of the operating parameter to obtain a time cost course for each of the plurality of special functions;
• - scheduling based on the temporal cost curves for each of the special functions;
• - Execute the special functions according to the created schedule.

One idea of the above method is to provide a generic cost function for each of the special functions rather than an execution priority. The generic cost function can be specified or the sum of individual sub cost functions. The generic cost function defines a history of a cost value over a selection of operating parameters identified as characterizing for the special function, such as e.g. an engine load, or a combustion air ratio (lambda probes) and is chosen so that the cost values for all considered special functions are comparable.

Furthermore, by analyzing a probable driving route and the resulting velocity or acceleration curve in conjunction with a state model implemented for the system function, the time profile of the operating parameter defined as an evaluation variable is determined e.g. the load curve or the storage level of a catalytic converter of the motor vehicle, predicts. Further evaluation variables may be the soot mass in the particulate filter for the exhaust system, the calculated NOx conversion, the regeneration (HC loading), the state of charge (SOC) of the battery, the temperature of an electric drive and the like.

Subsequently, a temporal cost profile of the cost value can be determined by combining the generic cost function with the time profile of the operating parameter. The temporal cost history gives over a given temporal horizon, the course of costs for the execution of the relevant special function.

Furthermore, occasional periods can be specified in the form of a further temporal cost profile, in which the execution of the special function should preferably be carried out. These occasional periods then have periods of negative cost shares. This reduces the cost values within the time course of costs within the occasional periods.

Based on the temporal cost history possible start times can then be determined for each special function. Based on the start times for the individual special functions and the associated cost values, a time schedule for the special functions is created in accordance with a schedule scheme.

The above method, based on the temporal cost curves of the special functions, allows them to be efficiently executed and to reduce the likelihood of aborts when executing the special functions.

Furthermore, the operating parameter may include an engine load or an engine speed.

It may be provided that the scheduling includes that one or more possible start times are determined from each of the cost curves of the plurality of special functions with a correspondingly assigned cost value and the scheduling is performed depending on the one or more possible start times with correspondingly assigned cost values.

Furthermore, local minima of the cost curves can be selected as possible start times, wherein in particular a start time of the temporal cost profile is selected as a possible start time for each of the special functions.

According to one embodiment, temporal cost curves of occasional periods for one or more of the special functions may be specified, wherein the temporal cost curves of the occasional periods specify negative cost values during at least one occasion period, wherein the temporal cost function for the relevant special functions are charged with the respective temporal cost curves of the occasional periods the cost functions are added.

In particular, the start of the at least one occasional period can be taken into account as possible starting times for the respective special function.

It can be provided that according to the sequence planning for each of the special functions, a start time is selected from the respective possible start times, which is assigned to the lowest cost value from the costs associated with the possible start times cost values of the relevant special function.

Furthermore, each of the special functions can be assigned an execution duration, wherein, with a temporal overlap of the special functions, one of the overlapping special functions is selected in order to shift its starting time until there is no longer any overlapping.

list of figures

• 1 eine schematische Darstellung eines Motorsystems mit diversen Komponenten,
• 2 ein Flussdiagramm zur Veranschaulichung eines Verfahrens zur Durchführung einer Bestimmung einer Reihenfolge für die Ausführung von Sonderfunktionen;
• 3 ein Diagramm einer beispielhaften lastabhängigen Kostenfunktion für eine Partikelregenerierung eines Dieselmotors;
• 4 ein Diagramm für einen prädizierten zeitlichen Verlauf einer Motorlast;
• 5 ein Diagramm für einen zeitlichen Kostenverlauf;
• 6 ein Diagramm für den Kostenverlauf während Gelegenheitsperioden;
• 7 ein resultierender Kostenverlauf als Grundlage zur Bestimmung von möglichen Startzeitpunkten zur Ausführung der betreffenden Sonderfunktion; und
• 8 ein Flussdiagramm zur Veranschaulichung einer Ablaufplanung.

Embodiments are explained below with reference to the accompanying drawings. Show it:

• 1 a schematic representation of an engine system with various components,
• 2 a flowchart for illustrating a method for performing a determination of an order for the execution of special functions;
• 3 a diagram of an exemplary load-dependent cost function for particle regeneration of a diesel engine;
• 4 a diagram for a predicted time course of an engine load;
• 5 a diagram for a temporal cost course;
• 6 a diagram for the cost course during occasional periods;
• 7 a resulting cost course as the basis for determining possible start times for executing the relevant special function; and
• 8th a flowchart illustrating a flowchart.

Description of embodiments

In 1 is an exemplary engine system 1 with an internal combustion engine 2 shown as a drive motor. In the illustrated embodiment, the internal combustion engine 2 formed in the form of a diesel engine, but this can also be designed as a gasoline engine or electric motor.

The internal combustion engine 2 Fresh air is supplied via an air supply system 3 fed. Combustion exhaust gases are from cylinders of the internal combustion engine 2 via an exhaust removal system 4 dissipated.

It can be an exhaust gas driven charging device 5 be provided, which is a turbine 51 and a compressor driven by the turbine 52 having. The turbine 51 is in the exhaust system 4 arranged to convert existing exhaust enthalpy into mechanical energy and to drive the compressor 52 to use. The compressor 52 is for the intake of fresh air for the air supply system 3 intended.

Furthermore, in the exhaust system 4 a particle filter 6 provided to filter out combustion exhaust gas particles from the combustion exhaust gas.

The engine system 1 may contain, in addition to the mentioned other components, the operation of the internal combustion engine 2 needed.

The engine system 1 is using a control unit 10 operated. The control unit 10 are based on state variables of the internal combustion engine 2 , such as speed, air filling in the cylinders, temperature of the supplied fresh air, engine temperature, load and based on a target load specification V, which can indicate, for example, a target torque of the engine, manipulated variables for position encoders for the operation of the internal combustion engine 2 in front. Using the positioners, the air supply, the fuel quantity, the boost pressure and others for the operation of an internal combustion engine 2 required parameters are controlled or regulated.

• - OxiCat Entschwefelung zur Beseitigung von Schwefelvergiftungen des Katalysators;
• - NSC Regeneration zur Wiederherstellung der NOx Speicherfähigkeit
• - NSC Regeneration zur Wiederherstellung der NOx Speicherfähigkeit mit angepassten Bedingungen für OnBoardDiagnose
• - NSC Entschwefelung zur Beseitigung von Schwefelvergiftungen des Katalysators
• - Diesel-Partikelfilter Regeneration
• - SCR Beseitigung von Vergiftungen des Katalysators durch Kohlenwasserstoffe
• - SCR Entschwefelung zur Beseitigung von Schwefelvergiftungen des Katalysators

According to legal requirements, components of the engine system 1 be periodically regenerated and / or adapted and / or monitored, for which at regular intervals special functions during operation of the engine system 1 must be executed. For example, it is necessary to use the particulate filter 6 regenerate at regular intervals to burn off deposited particles. For this, an engine mode is necessary in which the temperature of the combustion exhaust gas is increased to allow the regeneration of the particulate filter. Certain engine operating modes are required for the diagnosis and adaptation of components and control functions. For example, a low-load operation mode is necessary for the diagnosis and adaptation of a throttle valve actuator. Other special features may include, for example:

• - OxiCat desulfurization to eliminate sulfur poisoning of the catalyst;
• - NSC regeneration to restore NOx storage capability
• - NSC regeneration to restore NOx storage capability with customized conditions for onboard diagnostics
• - NSC desulfurization to eliminate sulfur poisoning of the catalyst
• - Diesel particulate filter regeneration
• - SCR Elimination of catalyst poisoning by hydrocarbons
• - SCR desulfurization to eliminate sulfur poisoning of the catalyst

• - SCR Adaptation von Systemabweichungen
• - SCR aktive OnBoardDiagnose
• - SCR passive OnBoardDiagnose mit angepassten Bedingungen zur erfolgreichen Durchführung
• - SCR Füllstandsabbau in Vorbereitung auf einen Temperaturanstieg
• - NOx Sensor OnBoardDiagnose

The following special functions do not necessarily require a special engine operating mode but possibly adjustments to the operating mode of the upstream components (eg EGR rate).

• - SCR adaptation of system deviations
• - SCR active on-board diagnostics
• - SCR passive on-board diagnostics with adapted conditions for successful implementation
• - SCR level reduction in preparation for a temperature rise
• - NOx sensor on board diagnostics

It is desirable to use time periods during engine operation in which the engine system performs to perform a special function 1 anyway operated in a mode that is suitable for performing the special functions.

The control unit 10 has a forecast unit 11 on or is associated with such. The forecast unit 11 Determines or prescribes a most probable driving route (MPP: _most probable path). This may be based on provided map data describing the course of the route including the prevailing topology.

Taking into account an average speed of individual route sections of the route, the route topology, the traffic volume, the weather conditions and the like, a temporal speed and acceleration course over a time horizon is determined from the most likely to be traveled route, from which a time profile of an operating parameter can be determined , As an operating parameter, the engine load is advantageously selected so that a predicted load profile is predetermined. However, other operating parameters such as engine speed as well as status parameters derived therefrom in subsystems may also be used. a storage level of a catalyst or the like can be specified.

It is now planned in the control unit 10 to carry out a method as shown by the flowchart of 2 is explained in more detail.

In step S1, the various special functions of the engine system become 1 defined and provided.

In step S2, a cost function is provided for each of the special functions, taking into account technical aspects such as fuel consumption, efficiency, pollutant emissions and the like. The cost function is usually specified manually or results from a weighting of the various technical aspects above depending on the engine load L. As a rule, the operating ranges required for the execution of the special function can be defined by the engine load. However, the cost function may also be based on another operating parameter of the internal combustion engine 2 , such as a speed or the like. For example, a cost function is qualitative in the 3 load-dependent shown. It can be seen that the execution of the relevant special function for a medium load range is preferred because there are low costs K, while the costs K increase in the direction of low and high load ranges or higher.

In step S3, a time profile of the operating parameter, e.g. the engine load L, for driving on a most likely traveled route within a predefined time horizon, such as between 15 and 45 minutes, between 30 and 60 minutes or the like predicts. The prediction is carried out using a predetermined most likely to travel route and based on map data, which define average speeds, maximum speeds, curvature as well as inclines and gradients of the route most likely to be traveled.

This results in a predicted time course of the engine load (or another operating parameter). As an example, such a predicted time history of engine load in 4 shown.

From the combination of the load-dependent cost function and the time profile of the predicted engine load L, a temporal cost profile, as in FIG 5 is shown determined. Thus, for each of the special functions, a temporal cost profile is obtained over the time horizon, which indicates the predicted time course of a cost value for the relevant special function.

In step S5, occasional periods may now be defined for one or more of the special functions that represent possible preferred periods for performing the special function. The opportunistic periods are given by giving an appropriate temporal cost course for the occasional periods, with the adverse periods being assigned negative cost values. For example, shows 6 such a course of the partial cost function for the occasional periods and their admission to the total temporal cost function.

In step S6, the temporal cost profile for each of the special functions is charged with the corresponding temporal cost profile for the occasional periods, in particular added up. In 7 the temporal cost curves for two special functions S1, S2 are shown accordingly, whereby both temporal cost curves take into account occasional periods.

In step S7, for each of the special functions S1, S2, local minima of the temporal cost curves outside the occasional periods and the start times of the occasional periods are determined, as is the case for example for the two exemplary cost curves of the 7 is shown. Thus, for each special function S1, S2, there are a number of possible start times of the corresponding special function and corresponding cost values.

• Sonderfunktion S1: die möglichen Startzeitpunkte T11, T12, T13 mit S1(T11), S1(T12), S1(T13) als entsprechende Kostenwerte.
• Sonderfunktion S2: die möglichen Startzeitpunkte T21, T22, T23 mit S2(T21), S2(T22), S2(T23) als entsprechende Kostenwerte.

It applies to:

• Special function S1: the possible start times T11, T12, T13 with S1 (T11), S1 (T12), S1 (T13) as corresponding cost values.
• Special function S2: the possible start times T21, T22, T23 with S2 (T21), S2 (T22), S2 (T23) as corresponding cost values.

In step S8, each of the special functions is then assigned to one of the start times and activated in accordance with the scheduling during the run of the route.

In 8th a flow chart illustrating the flowchart is shown.

For this purpose, in step S81, each special function is first assigned to that one of the previously determined start times, which has the lowest allocated costs. The special functions continue to be assigned a respective execution duration.

In step S82 it is checked whether two of the special functions overlap in time. If a temporal overlap of special functions is detected (alternative: yes), the method is continued with step S83, otherwise the scheduling is ended.

In step S83, a new possible start time, which corresponds to the end time of the respective other special function, is initially added to both overlapping special functions.

In step S84, for each of the overlapping special functions, the cost difference of the currently determined start time to the next one of the start times, which are sorted according to costs in ascending order, is not calculated for a renewed overlap leading start time.

The special function with the lowest absolute cost increase (regardless of the total cost level), which causes the least additional costs as a result of a shift, is assigned in S85 the new, free start time and the current one removed, whereby there is no longer any overlap.

If one of the overlapping special functions has no further starting point, the function is shifted with alternatively usable starting points.

If both special functions have no further possible start time, the function with the higher costs with decreasing cost gradient is transferred to the subsequent observation horizon for subsequent scheduling.

Subsequently, it returns to step S82.

Scheduling is performed until none of the special functions overlap.

Special functions for which no start time could be found within a time horizon, can be automatically scheduled in a next time horizon, which follows the given time horizon, since the start of the corresponding time horizon represents a possible start time.

Claims (11)

Method for operating an engine system (1), wherein the engine system (1) has a number of components which are monitored and / or adapted and / or regenerated by means of a plurality of special functions, comprising the following steps: Providing (S2) cost functions indicative of a history of a cost value based on an operating parameter of the engine system (1) for the plurality of special functions (S1, S2); - Providing (S3) a predicted time profile of the operating parameter over a most likely to be traveled route; - combining (S4) the cost functions in each case with the predicted time profile of the operating parameter in order to obtain a temporal cost profile for each of the plurality of special functions (S1, S2); - creating (S8) a scheduling based on the temporal cost curves for each of the special functions (S1, S2); - Execute the special functions according to the created schedule. Method according to Claim 1 wherein the operating parameter comprises an engine load or an engine speed. Method according to Claim 1 or 2 wherein the scheduling comprises determining from each of the cost curves of the plurality of special functions (S1, S2) one or more possible start times with a corresponding assigned cost value and the scheduling depending on the one or more possible start times (T11, T12, T13, T21, T22, T23) with correspondingly assigned cost values (S1 (T11), S1 (T12), S1 (T13), S2 (T21), S2 (T22), S2 (T23)). Method according to Claim 3 , where local minima of the cost curves are selected as possible start times and in particular a start time (T11, T12, T13, T21, T22, T23) of the time cost curve as a possible start time (T11, T12, T13, T21, T22, T23) for each the special functions (S1, S2) is selected. Method according to Claim 3 or 4 , wherein temporal cost curves of occasional periods for one or more of the special functions (S1, S2) are given, the temporal cost curves of the occasional periods specify negative cost values during at least one occasion period, the temporal cost function for the relevant special functions (S1, S2) with the respective temporal cost profiles of the occasional periods are charged or the cost functions are added. Method according to Claim 5 , wherein as possible start times (T11, T12, T13, T21, T22, T23) for the respective special function (S1, S2), the beginning of the at least one opportunity period are taken into account. Method according to one of Claims 3 to 6 in which, according to the scheduling, for each of the special functions (S1, S2) a start time from the respective possible start times (T11, T12, T13, T21, T22, T23) to which the lowest cost value is assigned from the cost values (S1 (T11), S1 (T12), S1 (T13), S2 assigned to the possible start times (T11, T12, T13, T21, T22, T23) (T21), S2 (T22), S2 (T23)) of the relevant special function (S1, S2) is assigned. Method according to Claim 7 , wherein each of the special functions is assigned an execution duration, wherein with a temporal overlap of the special functions (S1, S2) one of the overlapping special functions (S1, S2) is selected for its start time (T11, T12, T13, T21, T22, T23 ) until there is no overlap. Apparatus for operating an engine system (1), the engine system (1) comprising a number of components that are monitored and / or adapted and / or regenerated using a plurality of special functions (S1, S2), the apparatus being configured to: To provide cost functions indicating a history of a cost value based on an operating parameter of the engine system (1) for the plurality of special functions (S1, S2); to provide a predicted time profile of the operating parameter over a route most likely to be traveled; - To combine the cost functions each with the predicted time course of the operating parameter to obtain a temporal cost profile for each of the several special functions (S1, S2); to create a scheduling based on the temporal cost curves for each of the special functions (S1, S2); and - execute the special functions (S1, S2) according to the created schedule. Computer program adapted to perform all steps of a method according to one of Claims 1 to 9 perform. Machine-readable storage medium on which a computer program is based Claim 10 is stored.

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