DE102018213642A1 - Method and device for operating a drive system with an internal combustion engine - Google Patents

Abstract

The invention relates to a method for operating a drive system (1, 1 ') with an internal combustion engine (2) with a compression which is at least partially electrically effected with a compressor drive motor (64, 91), the drive system (1, 1') particularly supporting an electric motor comprises exhaust gas-driven charging device (6) or a purely electrically operated charging device (9), with the following steps:
- Check (S1) whether a load reduction has occurred;
- Determining a target compressor speed (S2, S3) depending on a driving situation;
- When determining the load reduction, operating (S4) the compressor drive motor (64, 91) in generator mode in order to reduce a compressor speed to the target compressor speed.

Description

Technical field

The invention relates to internal combustion engines in drive systems for motor vehicles, in particular measures for operating a charging device with supercharged internal combustion engines.

Technical background

Today's internal combustion engines are generally provided with charging devices which, in order to increase the performance of the internal combustion engine, provide an increased fresh air mass flow into the internal combustion engine and, in addition, an increased pressure, the so-called boost pressure. In order to reduce the size of the drive systems with such supercharged internal combustion engines and / or to improve the flexibility of the modes of charging, the charging devices can be operated completely electrically or can be provided as an exhaust gas-driven charging device with electrical support. The use of the electrically driven compressor or the electromotive support generally allows a performance-oriented design of the charging, which can be completely or partially decoupled from the amount of exhaust gas enthalpy available.

The publication DE 10 2015 215 912 A1 relates to a method for controlling an electric machine of an electrified exhaust gas turbocharger that can be operated in a generator operation or in a motor operation in a drive unit with a supercharged internal combustion engine and a stepped transmission. In this case, the electric machine is switched to generator operation or continues to be operated in this when a gear change to a higher gear is determined or when an impending gear change to a higher gear is determined.

From the publication DE 10 2015 216 307 A1 A method for operating a drive system with an internal combustion engine with an at least partially electrically induced compression is known. If a switching operation is established, the compressor output of the charging device is set by additionally providing electrically effected compressor power, in particular by additionally providing electrical power to the exhaust gas-driven charging device supported by an electric motor or to a purely electrically operated charging device, so that a charging pressure in at least at the end of the switching process a boost pressure section of the drive system is provided which is higher than a boost pressure which results from a compressor output corresponding to an exhaust gas enthalpy of the internal combustion engine provided during the switching process.

Disclosure of the invention

According to the invention, a method for operating a drive system with a supercharged internal combustion engine with an at least partially electrically induced compression of the charge air according to claim 1 and the corresponding device and the drive system according to the independent claims are provided.

Further refinements are specified in the dependent claims.

• - Überprüfen, ob eine Lastreduzierung des Verbrennungsmotors aufgetreten ist;
• - Bestimmen einer Soll-Verdichterdrehzahl abhängig von einer Fahrsituation; und
• - bei Feststellen der Lastreduzierung, Betreiben des Verdichterantriebsmotors in einem generatorischen Betrieb, um eine Verdichterdrehzahl auf die Soll-Verdichterdrehzahl oder in Richtung der Soll-Verdichterdrehzahl zu reduzieren.

According to a first aspect, a method is provided for operating a drive system with an internal combustion engine with a compression which is at least partially electrically effected with a compressor drive motor, the drive system comprising in particular an exhaust gas-driven charging device supported by an electric motor or a purely electrically powered charging device, with the following steps:

• - Check whether a load reduction of the internal combustion engine has occurred;
• - Determining a target compressor speed depending on a driving situation; and
• - When determining the load reduction, operating the compressor drive motor in generator mode in order to reduce a compressor speed to the target compressor speed or in the direction of the target compressor speed.

Compressors are often provided to increase the air supply to an internal combustion engine. With the aid of the compressor, fresh air is drawn in from the environment and provided under an increased pressure, the so-called boost pressure, in a charge air section of the air supply system, which serves as a fresh air reservoir for the controlled supply to the internal combustion engine. For this purpose, an exhaust gas-driven charging device is usually provided, which converts exhaust gas enthalpy into mechanical energy using a turbine and uses the mechanical energy to drive the compressor.

If the load is reduced during dynamic operation of the internal combustion engine, it may happen that at a high speed of the compressor the amount of fresh air delivered to the internal combustion engine is small, so that the compressor enters an operating range in which a so-called compressor pumping can occur. The compressor pumping is harmful to the mechanical components of the compressor and leads disruptive operating noises that should be avoided if possible.

In conventional supercharging devices, to avoid compressor pumping, a bypass air recirculation line surrounding the compressor with a controllable air recirculation valve is provided, which can be opened in the event of a sudden load shedding, such as can occur during a gearbox shift in a motor vehicle, in order to open up the fresh air mass flow through the To keep the compressor above a mass flow limit value specified by a characteristic compressor characteristic.

However, exhaust gas-driven charging devices are increasingly being supported by an electric motor, or the charging devices are provided as purely electrically operated charging devices. These enable generator operation, so that the speed of the compressor can also be actively reduced by converting the mechanical rotational energy into electrical energy. It is thus fundamentally possible, in order to avoid compressor pumping in the event of a sudden drop in load, to actively effect the speed of the compressor by generator operation of the drive motor which supports or operates the charging device.

Load reductions are often carried out in the context of only a brief reduction in a desired engine torque, as is the case, for example, with a shifting operation for a multi-step transmission or with dynamic driving operation. Too great a reduction in the compressor speed can therefore be disadvantageous since, in the event of a subsequent rapid increase in load or re-acceleration of the motor vehicle, the gas pressure in the charge air section is too low to quickly provide a requested target engine torque again. A request for electromotive support would be possible in order to quickly provide the required boost pressure, but this requires a higher requirement for electrical energy and thus ultimately higher fuel consumption. Therefore, the above method provides for the compressor output to be reduced to a predetermined setpoint value by means of generator operation of the compressor drive in the event of a load drop. Since the compressor capacity is determined by the compressor speed, the reduction in the compressor capacity can be achieved by reducing the compressor speed. Thus, in the event of a load drop, the compressor speed should be reduced to a compressor speed that is adapted to the driving situation.

For this purpose, a target compressor speed is specified. The target compressor speed for the reduction of the compressor speed in the case of a rapid load reduction is adjusted based on a vehicle state or a driving situation, from which a probability for a load increase that follows immediately or that takes place after a short period of time is estimated. If the probability of a subsequent increase in load within a predetermined period of time is high or if it is above a predetermined limit value, then a target compressor speed resulting from the vehicle state and the driving situation is set or adjusted as the target compressor speed.

This makes it possible to design the energy balance for the electromotive driving of the compressor drive motor and the recuperation of electrical energy from the charging device as efficiently as possible, so that the fuel consumption for the operation of the charging device can be reduced.

Furthermore, the check whether the load reduction has occurred can be carried out by determining a time gradient of the load profile and determining that the time gradient is below a predetermined gradient threshold or in terms of magnitude above a predetermined gradient threshold.

According to one embodiment, operating the compressor drive motor in a generator mode may include converting the rotational energy into recuperated electrical energy.

It can be provided that the target compressor speed is determined as a function of a load jump probability, the load jump probability indicating a probability with which, after the load reduction has been determined, a load increase with a time gradient above a predetermined load increase gradient threshold value occurs within a predetermined time period.

• - einer Fahrsituation, die abhängig von einem erkannten Fahrertyp angegeben wird, wobei der Fahrertyp beispielsweise über einen oder mehrere Fahrweiseparameter ermittelt wird, der insbesondere abhängig von einem Verlauf eines Fahrpedalbetätigungsgradienten, einem Verlauf eines Lenkwinkelgradienten und/oder einem Verlauf von Fahrzeugbeschleunigungen ermittelt wird,
  • - einem Schaltvorgang eines Schaltgetriebes;
  • - einer durch manuelle Wahl eines Fahrmodus angegebenen Fahrsituation;
  • - einer durch externe Informationen angegebenen Fahrsituation, die insbesondere durch eine Verkehrsinformation bestimmt ist; und
  • - einer durch Streckeninformationen insbesondere aus einem Navigationssystem bestimmten Fahrsituation.

In particular, the load jump probability can be determined depending on one or more of the following driving situations:

• a driving situation that is specified as a function of a recognized driver type, the driver type being determined, for example, via one or more driving style parameters, which is determined in particular as a function of a gradient of an accelerator pedal actuation gradient, a gradient of a steering angle gradient and / or a gradient of vehicle accelerations,
  • - A switching operation of a manual transmission;
  • - a driving situation specified by manual selection of a driving mode;
  • - a driving situation indicated by external information, which is determined in particular by traffic information; and
  • - A driving situation determined by route information, in particular from a navigation system.

Furthermore, if there is at least one of the driving situations, the load jump probability can be set to a value specified in accordance with an assignment function and depending on the driving situation in question and / or in particular if there is a change in at least one of the driving situations, the load jumping probability can be changed incrementally depending on the driving situation in question.

• - zu überprüfen, ob eine Lastreduzierung aufgetreten ist;
• - eine -Verdichterdrehzahl abhängig von einer Fahrsituation zu bestimmen; und
• - bei Feststellen der Lastreduzierung, den Verdichterantriebsmotor in einem generatorischen Betrieb zu betrieben, um eine Verdichterdrehzahl auf die Soll-Verdichterdrehzahl oder in Richtung der Soll-Verdichterdrehzahl zu reduzieren.

According to a further aspect, a device is provided for operating a drive system with an internal combustion engine with a compression which is at least partially electrically effected with a compressor drive motor, the drive system comprising in particular an exhaust gas-driven charging device supported by an electric motor or a purely electrically powered charging device, the device being designed to :

• - to check whether a load reduction has occurred;
• - To determine a compressor speed depending on a driving situation; and
• - When determining the load reduction, to operate the compressor drive motor in generator mode in order to reduce a compressor speed to the target compressor speed or in the direction of the target compressor speed.

According to a further aspect, a drive system is provided with an internal combustion engine, the above device and with either an electromotive-assisted exhaust gas-powered charging device or a purely electric charging device.

list of figures

• 1 eine Darstellung eines Antriebssystems mit einer elektromotorisch unterstützten abgasgetriebenen Aufladeeinrichtung;
• 2 eine Darstellung eines Antriebssystems mit einem elektromotorisch betriebenen Verdichter; und
• 3 ein Flussdiagramm zur Veranschaulichung eines Verfahrens zum Betreiben der Antriebssysteme der 1 und 2.

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

• 1 a representation of a drive system with an electromotive-assisted exhaust gas-powered charging device;
• 2 a representation of a drive system with an electric motor-driven compressor; and
• 3 a flowchart to illustrate a method for operating the drive systems of the 1 and 2 ,

Description of embodiments

In 1 is a schematic drive system 1 shown. The drive system 1 includes an internal combustion engine 2 with multiple cylinders 3 , The internal combustion engine 2 can be designed, for example, as a gasoline engine, a diesel engine or as another air-guided or fuel-guided internal combustion engine.

The internal combustion engine 2 becomes air through an air supply system 4 fed, and combustion gases from the cylinders 3 of the internal combustion engine 2 are through an exhaust gas tract 5 dissipated. In the air supply system 4 and in the exhaust gas tract 5 is an exhaust gas powered charger 6 intended. The charger 6 is with the exhaust gas tract 5 coupled to convert exhaust gas enthalpy from combustion exhaust gas into mechanical energy. The mechanical energy is used to create ambient air in the air supply system 4 to condense.

The charger 6 has a turbine 61 on that in the exhaust duct 5 is provided to convert the exhaust gas enthalpy present in the combustion exhaust gas into a rotational movement of a shaft 62 implement. The wave 62 the charger 6 is with a compressor 63 coupled, which depends on the rotation of the shaft 62 provides compression performance to ambient air via an input section 41 suck in and under a boost pressure in an outlet section 42 to provide. The entrance section 41 of the air supply system 4 can continue with an air filter 43 be provided, which filters the fresh air drawn in.

In the output section 42 of the air supply system 4 is a throttle valve 44 provided between a boost pressure section 46 and an intake manifold section 47 , the parts of the output section 42 represent is arranged. The throttle valve 44 serves to supply air to the combustion chambers of the cylinders 3 of the internal combustion engine 2 from the boost pressure section 46 to control.

In the charge air section 46 can be an intercooler 45 be provided by the compression in the compressor 63 heated charge air cools. This allows the density of those in the charge air section 46 located charge air can be increased, so that a higher air filling in the cylinders 3 of the internal combustion engine 2 can be achieved.

In the air supply system 4 can the compressor 63 still be short-circuited by a charge pressure discharge line with a charge pressure discharge valve arranged therein.

In the illustrated embodiment, the shaft 62 with a compressor drive motor 64 , which is designed as an electric motor (electromotive support), coupled, so that this corresponds to a control an additional torque on the shaft 62 can apply to increase a compression power by an electric motor. Furthermore, the compressor drive motor 64 can also be operated as a generator by converting the shaft's mechanical rotational energy 62 in electrical energy on the one hand the speed of the compressor 63 to reduce and on the other hand to recuperate electrical energy that can be used or stored elsewhere.

The charger 6 can also be provided with a charge controller, which in the embodiment shown has a variably controllable wastegate valve 65 in a bypass line 66 is trained. The bypass line 66 connects the inlet and outlet sides of the turbine 61 , so that depending on a control of the wastegate valve 65 an efficiency of the turbine 61 can be adjusted. In particular, it is specified what proportion of the exhaust gas enthalpy in kinetic power, ie in rotational power of the shaft 62 is implemented. Instead of the wastegate valve 65 in the bypass line 66 A VTG actuator (VTG: Variable Turbine Geometry) can also be provided as a load controller to determine the efficiency of the turbine 61 adjust or adjust the proportion of the exhaust gas enthalpy converted into mechanical power.

The internal combustion engine 2 has an output shaft 8th on that via a clutch 11 with a manual transmission 12 connected is. The coupling 11 can be operated manually, ie for example via a clutch pedal, or automatically, for example by signaling by a transmission control unit (not shown). The manual transmission 12 allows you to set different speed levels.

It is a control unit 10 provided the internal combustion engine 2 depending on the state variables of the drive system 1 operates. For example, a speed of the internal combustion engine can be used as state variables 2 , a boost pressure of the compressed fresh air (charge air) in the boost pressure section 46 , a charge air temperature of the charge air in the boost pressure section 46 , an exhaust gas temperature of the exhausted combustion exhaust gases, an intake air mass flow on the inlet side of the compressor 63 and similar state variables can be recorded or modeled using appropriate sensors.

The control unit 10 is designed to, depending on the detected and provided state variables, actuators, such as a throttle valve actuator for setting the throttle valve 44 , Fuel injectors (not shown), the wastegate valve 65 , the compressor drive motor 64 and the like to drive the internal combustion engine 2 to control according to a predetermined target torque.

In 2 is another drive system 1' shown, similar to the drive system 1 the 1 is trained. Instead of the exhaust-driven charging device 6 is an electrically powered charger 9 provided a compressor drive motor 91 and a compressor 92 having. The electrically powered charger 9 can be controlled independently of an existing exhaust gas enthalpy, since the compression performance is only provided by supplying electrical power. In this embodiment too, the compressor drive motor can 91 operated as a generator to the rotational energy of the compressor 63 to reduce quickly by converting this into electrical energy.

The drive system 1 and the drive system 1' can through the control unit 10 according to one below based on the flowchart of FIG 3 described method for operating the drive system 1 . 1' with an electromotive-assisted exhaust-driven charging device 6 or an electrically powered charger 9 respectively.

In step S1 it is first checked whether a load reduction has occurred or has been requested. The load reduction is recognized by determining a time gradient of the load profile and determining that the time gradient is below a predetermined (negative) load reduction gradient threshold or in terms of magnitude above a predetermined (positive) load reduction gradient threshold. If this is the case (alternative: yes), the procedure goes with step S2 otherwise, go to step S1 jumps back.

Since the exhaust gas enthalpy provided in the event of a sudden reduction in load only decreases with a delay and to the compressor 63 on Moment of inertia, the compressor works 63 the charger 6 continues at very high compressor speed and tries to promote a gas mass flow that is no longer due to the low load requirement from the internal combustion engine 2 is recorded. This increases the charge pressure in the charge air section and creates it above the compressor 63 a back pressure resulting in a significantly reduced gas mass flow across the compressor 63 leads. In this case, in order to achieve compressor operation without compressor pumps, it is necessary to reduce the compressor speed quickly. For this the compressor drive motor 64 . 91 operated as a generator and thereby recuperating electrical energy that can be stored or used in any other way. The compressor speed should be reduced using the generator operation of the compressor drive motor 64 . 91 take place in such a way that the compressor speed does not fall below a predetermined target compressor speed.

• - Die Lastsprungwahrscheinlichkeit kann abhängig von mindestens einem Fahrweiseparameter, der einen Fahrertyp bestimmt, angegeben werden. Der Fahrertyp kann beispielsweise über Parameter der Fahrweise, wie z. B. eines Verlaufs eines Fahrpedalbetätigungsgradienten und/oder eines Verlaufs eines Lenkwinkelgradienten und/oder eines Verlaufs von Fahrzeugbeschleunigen und dergleichen ermittelt werden. Dabei kann die Lastsprungwahrscheinlichkeit umso höher angenommen werden, je höher die Dynamik ist, mit der der Fahrer das Kraftfahrzeug bewegt. Die Dynamik wird durch den mindestens einen Fahrweiseparameter kann beispielsweise als ein Maß der Variation des Fahrpedalbetätigungsgradienten und/oder des Lenkwinkelgradienten und/oder des Fahrzeugbeschleunigens angenommen werden. Die Fahrweiseparameter können beispielsweise durch einen nach einer Hochpassfilterung mit einer von dem vorgegebenen Zeitraum bestimmten Zeitkonstante verbleibenden Anteil der betrachteten Verläufe angegeben werden. Alternativ kann die Dynamik der aktuellen Fahrweise mit einer Dynamik einer vorangehenden Fahrweise, beispielsweise durch Vergleichen der Fahrweiseparameter mit historischen Fahrweiseparametern bzw. den entsprechenden Durchschnitten, verglichen werden. Wird eine tendenzielle Erhöhung der Fahrdynamik erkannt, so kann die Lastsprungwahrscheinlichkeit inkrementell erhöht werden. Wird analog eine tendenzielle Verringerung der Fahrdynamik erkannt, so kann die Lastsprungwahrscheinlichkeit inkrementell reduziert werden.
• - Wird ein Schaltvorgang eines Schaltgetriebes erkannt, so kann ebenfalls von einer hohen Lastsprungwahrscheinlichkeit einer schnellen Lasterhöhung im Anschluss an die beim Auskuppeln auftretende plötzliche Lastreduzierung ausgegangen werden. Eine entsprechende Lastsprungwahrscheinlichkeit kann abhängig von der gewählten Schaltstufe entsprechend einer Wertezuordnung (Lookup-Tabelle) vorgegeben werden.
• - Weiterhin kann durch manuelle Wahl eines Fahrmodus, beispielsweise eines Sportmodus, ein Wunsch nach einer dynamischen oder weniger dynamischen Betriebsweise des Kraftfahrzeugs erkannt werden und entsprechend die Lastsprungwahrscheinlichkeit vorgegeben werden. Insbesondere kann die Lastsprungwahrscheinlichkeit qualitativ oder quantitativ vorgegeben werden. Der Lastsprungwahrscheinlichkeit kann direkt eine Soll-Verdichterdrehzahl zugeordnet werden.
• - Darüber hinaus können externe Informationen, wie beispielsweise Verkehrsinformationen, ausgewertet werden, um die Lastsprungwahrscheinlichkeit zu bestimmen oder zu ändern. Wird mithilfe eines Fahrerassistenzsystems beispielsweise ein stehendes oder langsamer vorausfahrendes Fahrzeug oder eine rote Ampel erkannt, kann die Lastsprungwahrscheinlichkeit als niedrig angenommen werden, da die Wahrscheinlichkeit für eine schnelle Lasterhöhung im Anschluss auf die plötzliche Lastreduzierung durch eine weitere Verkehrsbehinderung eher gering angenommen werden kann. In gleicher Weise können auch Stauinformationen behandelt werden.
• - Weiterhin können Streckeninformationen zum Beispiel aus dem Navigationssystem ausgewertet werden. Wird auf Basis einer aktuellen Zielführung oder gelernten Streckeninformation ein Straßenabschnitt erkannt, auf dem das Fahrzeug nur mit geringer Geschwindigkeit bewegt werden kann, kann ebenfalls von einer geringen Lastsprungwahrscheinlichkeit einer schnellen Lasterhöhung ausgegangen werden. Wird dagegen eine Strecke mit vielen Kurven erkannt, kann eine höhere Lastsprungwahrscheinlichkeit angenommen werden.

In step S2 a load jump probability is therefore determined as a function of a vehicle state or a driving situation. The load jump probability corresponds in particular to a probability with which the sudden load reduction is followed by a rapid load increase within a predetermined time period, that is to say a load increase which has a time gradient above a predetermined load increase gradient threshold value. This probability of a load jump can depend on or be determined by one or more of the following factors:

• - The load jump probability can be specified depending on at least one driving style parameter that determines a driver type. The driver type can, for example, via parameters of the driving style, such as. B. a course of an accelerator pedal actuation gradient and / or a course of a steering angle gradient and / or a course of vehicle accelerations and the like can be determined. The higher the dynamics with which the driver moves the motor vehicle, the higher the probability of a load jump. The dynamics is determined by the at least one driving style parameter, for example, as a measure of the variation in the accelerator pedal actuation gradient and / or the steering angle gradient and / or the vehicle acceleration. The driving style parameters can be specified, for example, by a portion of the curves under consideration after a high-pass filtering with a time constant determined by the predetermined period. Alternatively, the dynamics of the current driving style can be compared with a dynamics of a previous driving style, for example by comparing the driving style parameters with historical driving style parameters or the corresponding averages. If a tendency to increase driving dynamics is recognized, the load jump probability can be increased incrementally. Similarly, if a tendency to reduce driving dynamics is recognized, the load jump probability can be reduced incrementally.
• - If a shifting process of a manual transmission is recognized, then a high load jump probability of a rapid increase in load following the sudden load reduction occurring when disengaging can also be assumed. A corresponding load jump probability can be specified depending on the selected switching level according to a value assignment (lookup table).
• - Furthermore, by manually selecting a driving mode, for example a sport mode, a request for a dynamic or less dynamic mode of operation of the motor vehicle can be recognized and the load jump probability can be specified accordingly. In particular, the load jump probability can be specified qualitatively or quantitatively. A target compressor speed can be directly assigned to the load jump probability.
• - In addition, external information, such as traffic information, can be evaluated in order to determine or change the load jump probability. If, for example, a driver assistance system detects a stationary or slower vehicle in front or a red traffic light, the probability of a load jump can be assumed to be low, since the probability of a rapid increase in load following the sudden reduction in load due to another traffic disruption can be assumed to be rather low. Congestion information can also be treated in the same way.
• - Route information can also be evaluated, for example from the navigation system. If a road section is recognized on the basis of current route guidance or learned route information, on which the vehicle can only be moved at low speed, it can also be assumed that there is a low probability of a load jump of a rapid increase in load. If, on the other hand, a route with many curves is recognized, a higher load jump probability can be assumed.

In step S3 the target compressor speed is now set as a function of the previously determined load jump probability, so that the target compressor speed is set the higher the higher the load jump probability and vice versa. The target compressor speed can be specified according to a specified functional relationship depending on the load jump probability, for example using a lookup table. If the load jump probability is determined from the driving dynamics, which is specified by the driving style parameters, the higher the dynamics of the driving operation, the higher the target compressor speed, for example.

In step S4 is made using a regulation for the compressor drive motor 64 . 91 the compressor speed is regulated to the target compressor speed. This can be achieved with a simple state controller or PD controller, for example. Then the procedure with step S1 continued.

With the above method it is possible to reduce the likelihood of a sudden load reduction and a corresponding braking of the shaft 62 the charger 6 with a subsequent increase in load, electrical energy has to be used again in order to quickly increase the compressor speed again. In particular, it is possible to reduce the compressor speed in the event of load reductions that are likely to occur only briefly, so that electrical energy is used to operate the compressor drive motor 64 . 91 can be saved in comparison to a conventional mode of operation of such charging devices 6 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• DE 102015215912 A1 [0003]
• DE 102015216307 A1 [0004]

Claims (10)

Method for operating a drive system (1, 1 ') with an internal combustion engine (2) with a compression which is at least partially effected electrically with a compressor drive motor (64, 91), the drive system (1, 1') in particular an electromotive-assisted exhaust gas-powered charging device (6 ) or a purely electrically operated charging device (9), with the following steps: - Check (S1) whether a load reduction has occurred; - Determining a target compressor speed (S2, S3) depending on a driving situation; and - When determining the load reduction, operating (S4) the compressor drive motor (64, 91) in a generator mode to reduce a compressor speed to the target compressor speed or in the direction of the target compressor speed. Procedure according to Claim 1 , wherein the checking whether the load reduction has occurred is carried out by determining a temporal gradient of the load profile and determining that the temporal gradient is below a predetermined gradient threshold or in terms of magnitude above a predetermined gradient threshold. Procedure according to Claim 1 or 2 wherein the operation of the compressor drive motor (64, 91) in a generator operation comprises a conversion of the rotational energy into recuperated electrical energy. Procedure according to one of the Claims 1 to 3 , wherein the target compressor speed is determined as a function of a load jump probability, the load jump probability indicating a probability with which, after determining the load reduction, a load increase with a time gradient above a predetermined load increase gradient threshold value occurs within a predetermined time period. Procedure according to Claim 4 The load jump probability is determined as a function of one or more of the following driving situations: a driving situation which is specified as a function of a recognized driver type, the driver type being determined, for example, via one or more driving style parameters, in particular a course of an accelerator pedal actuation gradient, a course of a steering angle gradient and / or a course of vehicle accelerations is determined, - a shifting process of a manual transmission; - a driving situation specified by manual selection of a driving mode; a driving situation indicated by external information, which is determined in particular by traffic information; - A driving situation determined by route information, in particular from a navigation system. Procedure according to one of the Claims 4 to 5 , wherein in the presence of at least one of the driving situations the load jump probability is set to a value specified according to an assignment function and depending on the driving situation concerned and / or in particular if there is a change in at least one of the driving situations the load jump probability is changed incrementally depending on the driving situation concerned. Device for operating a drive system (1, 1 ') with an internal combustion engine (2) with a compression which is at least partially effected electrically with a compressor drive motor (64, 91), the drive system (1, 1') in particular an exhaust gas driven charging device (6) supported by an electric motor ) or a purely electrically operated charging device (9), the device being designed to: - to check whether a load reduction has occurred; - Determining a target compressor speed depending on a driving situation; - When determining the load reduction, operating the compressor drive motor (64, 91) in a generator mode to reduce a compressor speed to the target compressor speed or in the direction of the target compressor speed. Drive system (1, 1 ') with an internal combustion engine (2) according to the device Claim 7 and with either an electromotive-assisted exhaust-driven charging device (6) or a purely electrically operated charging device (9). Computer program which is set up to carry out all steps of a method according to one of the Claims 1 to 6 perform. Machine-readable storage medium on which a computer program Claim 9 is saved.

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