DE102018207708A1 - Method and device for operating a supercharged internal combustion engine - Google Patents

Abstract

The invention relates to a method for operating an engine system (1) with a supercharged internal combustion engine (2), comprising the following steps: - determining a compression ratio (Π) of a compressor (62) of a charging device (6) of the engine system (1); S3) a compressor speed of the compressor (62) using a speed sensor (65); - determining (S4) a compressor mass flow (ṁ) using a predetermined compressor map as a function of the compression ratio (Π) and the compressor speed; - plausibility checking of a further mass flow in the engine system (1) depending on the determined compressor mass flow (ṁ); - operation (S5-S9) of the engine system (1) depending on the plausible further mass flow.

Description

Technical field

The invention relates to supercharged internal combustion engines, in particular internal combustion engines with exhaust gas-driven charging devices, in which a function of a compressor is described with the aid of a compressor map. Furthermore, the present invention relates to the checking of measured or modeled mass flow data of mass flows in an internal combustion engine and the application of corrections to correct faulty sensor values or faulty model values e.g. B. to correct due to long-term drift.

Technical background

To improve the air supply in an internal combustion engine, supercharging devices are often provided which provide an increased gas pressure at the inlet valves of the cylinders of the internal combustion engine with the aid of a compressor. The compressors of the charging devices are often operated using available exhaust gas enthalpy, kinetic energy being provided with the aid of an exhaust gas turbine in order to drive the compressor. Alternatively or additionally, such compressors can also be driven by an electric motor.

The properties of such a compressor are described by a compressor map, which shows a dependency between a compressor-pressure ratio between the outlet-side pressure and the inlet-side pressure, a normalized mass flow, i. H. describes a mass flow, which is normalized to an ambient pressure and a gas temperature, and a compressor speed.

The publication WO 2001/029386 A1 describes a method in which, using a compressor map recorded for the turbocharger, which specifies the relationship between the turbine speed, the ratio of the air pressures on the pressure side and the suction side of the compressor and the air mass flow supplied to the compressor in the intake pipe on the suction side of the compressor, one of these sizes is derived when the other sizes are specified. In addition, the derived variables can also be used to diagnose the sensors measuring the same variables.

The publication DE 10 2014 201 947 B3 discloses a method for determining the charge air mass flow through an intake line of an internal combustion engine equipped with an engine control system with an exhaust gas turbocharger, an open-loop charge air mass flow being extracted from a map stored in the engine control system, which indicates a charge air mass flow associated with a measured compressor pressure ratio and a measured turbocharger speed. An associated turbocharger speed is modeled from the measured compressor pressure ratio and an entered charge air mass flow. A closed-loop charge air mass flow is calculated as the sum of the open loop charge air mass flow and an offset value, which is a scaled difference between the measured turbocharger speed and the modeled turbocharger speed. The calculation of the closed-loop charge air mass flow is carried out repeatedly.

Disclosure of the invention

According to the invention, a method for operating an engine system with a supercharged internal combustion engine by plausibility checking of a mass flow according to claim 1 and a device and an engine system according to the independent claims are provided.

Further configurations are specified in the dependent claims.

• - Bestimmen eines Verdichtungsverhältnis eines Verdichters einer Aufladeeinrichtung des Motorsystems;
• - Bestimmen einer Verdichterdrehzahl des Verdichters mithilfe eines Drehzahlsensors;
• - Ermitteln eines Verdichtermassenstroms mithilfe eines vorgegebenen Verdichterkennfelds abhängig von dem Verdichtungsverhältnis und von der Verdichterdrehzahl;
• - Plausibilisieren eines weiteren Massenstroms in dem Motorsystem abhängig von dem ermittelten Verdichtermassenstrom.

According to a first aspect, a method for operating an engine system with a supercharged internal combustion engine is provided; with the following steps:

• Determining a compression ratio of a compressor of a supercharger of the engine system;
• - Determining a compressor speed of the compressor using a speed sensor;
• - Determining a compressor mass flow using a predetermined compressor map as a function of the compression ratio and the compressor speed;
• - Plausibility check of a further mass flow in the engine system depending on the determined compressor mass flow.

One idea of the above method is to determine an actual mass flow through the compressor using a predetermined compressor map that describes a compressor of a charging device in an engine system with an internal combustion engine. The mass flow through the compressor determined in this way can then be used to diagnose errors in the determination of other mass flow data in the internal combustion engine and to correct these mass flow data. A normalized compressor mass flow specification is thus determined by determining the pressure on the output side or the input side of the compressor and determining the compressor speed and is based on the actual compressor mass flow rate is calculated by the compressor based on the ambient pressure and the ambient temperature. The actual compressor mass flow data can now be used for plausibility checking, checking and / or correcting further measured or modeled mass flow data in the internal combustion engine.

In particular, a mass flow measurement value or a mass flow model value can be checked. If a deviation occurs, the mass flow measured value or the mass flow model value can be corrected using a correction. This allows measurement and modeling errors to be corrected and, in particular, deviations caused by aging effects to be compensated for.

By using the compressor of a charging device and options for determining the compressor speed and the inlet and outlet pressure on the compressor, it is possible to use the compressor map for diagnosis and correction of mass flow quantities in the engine system.

Furthermore, the further mass flow can comprise a fresh air mass flow, the plausibility check of the fresh air mass flow being carried out in particular when the low pressure exhaust gas recirculation valve of a low pressure exhaust gas recirculation is closed.

In particular, depending on a result of the plausibility check, a correction of the determination of the fresh air mass flow can be carried out, in particular by specifying a correction variable which acts multiplicatively or additively on the measured value of the fresh air mass flow in order to obtain a corrected fresh air mass flow rate.

According to one embodiment, the further mass flow can comprise an engine mass flow, the plausibility check of the engine mass flow being carried out in particular when the high-pressure exhaust gas recirculation valve of a high-pressure exhaust gas recirculation is closed.

Thus, for example, a fresh air mass flow rate, which is from an input-side area of the air supply system, for. B. is measured with the aid of an HFM mass flow sensor or the like, or an engine mass flow indication which indicates a mass flow into the cylinders of the internal combustion engine, checked and corrected if necessary.

In particular, depending on a result of the plausibility check, a correction of an air expenditure parameter, on which a determination of the engine mass flow is based, can be carried out, in particular by specifying a correction variable which acts on the air expenditure parameter multiplicatively or additively.

It can be provided that the compression ratio is determined as a function of a compressor outlet pressure, which is determined either by direct measurement with a boost pressure sensor or by an indirect measurement of an intake manifold pressure, in particular with an intake manifold pressure sensor, and a calculation model of a pressure drop across a charge air cooler, and the compressor inlet pressure either by direct measurement with a compressor inlet pressure sensor or by measuring the ambient pressure in conjunction with a model of the pressure drop across an air filter and an inlet throttle valve (if present).

Furthermore, the compressor map can indicate a dependency between a compression ratio across the compressor, a speed of rotation of the compressor and a compressor mass flow standardized to a reference pressure and a reference temperature.

Provision can be made for the compressor speed to be compared with the compressor ratio over the compressor map in a range in which the gradient of the course of a compressor ratio at constant speed does not exceed a predetermined gradient threshold. The detected deviation can be applied to a corresponding sensor or model value or the entire compressor map by means of an additive or multiplicative correction variable.

In particular, this correction can be applied before determining a correction quantity for a fresh air mass flow or for an engine mass flow.

• - ein Verdichtungsverhältnis eines Verdichters einer Aufladeeinrichtung des Motorsystems zu bestimmen;
• - eine Verdichterdrehzahl des Verdichters mithilfe eines Drehzahlsensors zu bestimmen;
• - einen Verdichtermassenstrom mithilfe eines vorgegebenen Verdichterkennfelds abhängig von dem Verdichtungsverhältnis und von der Verdichterdrehzahl zu ermitteln;
• - einen weiteren Massenstrom in dem Motorsystem abhängig von dem ermittelten Verdichtermassenstrom zu plausibilisieren; und
• - das Motorsystem abhängig von dem plausibilisierten weiteren Massenstrom zu betreiben.

According to a further aspect, a device for operating an engine system with a supercharged internal combustion engine is provided, the device being designed to:

• - determine a compression ratio of a compressor of a supercharger of the engine system;
• - determine a compressor speed of the compressor using a speed sensor;
• - Determine a compressor mass flow using a predetermined compressor map as a function of the compression ratio and the compressor speed;
• - to plausibility check a further mass flow in the engine system depending on the determined compressor mass flow; and
• - To operate the engine system depending on the plausible further mass flow.

According to a further aspect, an engine system with an internal combustion engine and the above device is provided.

list of figures

• 1 eine schematische Darstellung eines Motorsystems mit einer abgasgetriebenen Aufladeeinrichtung;
• 2 eine Darstellung eines Verdichterkennfelds für einen beispielhaften Verdichter einer abgasgetriebenen Aufladeeinrichtung; und
• 3 ein Flussdiagramm zur Veranschaulichung eines Verfahrens zur Überprüfung eines gemessenen oder modellierten Massenstroms und zur Ermittlung einer Korrekturgröße.

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

• 1 is a schematic representation of an engine system with an exhaust gas-driven charging device;
• 2 a representation of a compressor map for an exemplary compressor of an exhaust gas-driven charging device; and
• 3 a flowchart to illustrate a method for checking a measured or modeled mass flow and for determining a correction quantity.

Description of embodiments

1 shows a schematic representation of an engine system 1 with an internal combustion engine 2 , the number (in the given embodiment four) of cylinders 3 having. The internal combustion engine 2 corresponds, for example, to a reciprocating piston engine, in particular an Otto engine or a diesel engine, and is controlled by the supply of air and fuel into the cylinders 3 operated.

The supply of fresh air to the cylinders 3 of the internal combustion engine 2 takes place via an air supply system 4 , Combustion gases are created via an exhaust system 5 from the internal combustion engine 2 dissipated.

It is an exhaust gas powered charger 6 provided an exhaust gas turbine 61 has, through which the combustion exhaust gas is passed. The exhaust gas turbine 61 is mechanical, especially via a shaft 63 with a compressor 62 coupled so that in the exhaust gas turbine 61 Exhaust gas enthalpy converted into kinetic energy to drive the compressor 62 is used to go through an input side of the compressor 62 Suck in ambient air and this under an increased boost pressure in a boost pressure section 43 of the air supply system 4 provide. The proportion of the exhaust gas enthalpy converted into mechanical energy can be achieved by means of a gas turbine 61 arranged charge controller 64 (e.g. VTG actuator (VTG: variable turbine geometry), wastegate valve or the like) can be controlled.

In the air supply system 4 can a throttle 41 be arranged having a downstream intake manifold section 47 from the upstream boost section 43 separates. Upstream of the throttle valve 41 can be an intercooler 42 be arranged to cool the charge air.

The engine system 1 can continue in a manner known per se a high-pressure exhaust gas recirculation line 7 with a high pressure exhaust gas recirculation cooler 71 and a high pressure exhaust gas recirculation valve 72 have part of the combustion exhaust gas from the exhaust system 5 into the air supply system 4 , especially in the intake manifold section 47 respectively. This makes it possible to supply the amount of fresh air for a combustion process in the cylinders by supplying inert combustion exhaust gas 3 to reduce so as to reduce the formation of nitrogen oxides.

In the air supply system 4 can continue on the inlet side of the compressor 62 an air mass sensor 44 be provided.

Furthermore, a boost pressure sensor 45 be provided, the output side of the compressor 62 is arranged to in a boost section of the air supply system 4 a boost pressure (compressor outlet pressure p _{2, t} ), ie a pressure in the boost pressure section 47 to determine the gas present. Alternatively, in conjunction with a model of a pressure drop across an intercooler 42 that is downstream to the compressor 62 connects, and if necessary with a model of a throttle valve also based on a boost pressure using a manifold pressure sensor that measures a gas pressure in a manifold section of the air supply system.

Furthermore, the engine system 1 a low-pressure exhaust gas recirculation line in a manner known per se 8th with a low pressure exhaust gas recirculation cooler 81 and a low pressure exhaust gas recirculation valve 82 have a portion of the combustion exhaust gas from a downstream of the exhaust gas turbine 61 arranged part of the exhaust system 5 into an upstream of the compressor 62 arranged part of the air supply system 4 respectively. This makes it possible to supply the amount of fresh air for a combustion process in the cylinders by supplying inert combustion exhaust gas 3 to reduce so as to reduce the formation of nitrogen oxides.

In addition, a speed sensor 65 be provided to detect a supercharger speed. The Speed sensor 65 can on the shaft 63 , on the turbine 61 or on the compressor 62 be arranged and determines a rotational speed of the compressor based on detection methods known per se 62 ,

Furthermore, a pressure sensor can be provided which has an inlet-side pressure on the compressor 62 (Compressor inlet pressure p _{1, t} ) measures. Alternatively, an ambient pressure sensor 48 be provided to measure an ambient pressure. If an air filter is provided 9 can by using the ambient pressure sensor 48 and a model of the pressure drop across the air filter 9 the pressure immediately on the inlet side of the compressor 62 than the compressor inlet pressure p _{1, t} be determined.

Furthermore, an intake temperature sensor 49 be provided to measure an ambient temperature so that a compressor inlet temperature T1 , t is known. When using a low pressure exhaust gas recirculation 8th can the compressor inlet temperature T _{1, t} on the inlet side of the compressor 62 using a model depending on a measured or modeled temperature on the output side of the low-pressure exhaust gas recirculation cooler 81 in conjunction with a low pressure exhaust gas recirculation rate.

The engine system 1 is using a control unit 10 operated by the control of various actuators, such as the load controller 64 , the throttle valve 41 , the EGR valves 72 and 82 , and the injection valves for specifying a fuel injection quantity the operation of the internal combustion engine 2 certainly. The actuators can be controlled based on a target load specification, which can be derived, for example, from a driver's desired torque or a position of an accelerator pedal, and based on one or more sensor variables, which are determined, for example, by the boost pressure sensor 45 measured boost pressure, one by the charge air temperature sensor 46 measured charge air temperature, one by an exhaust gas temperature sensor 51 measured exhaust gas temperature, a fresh air mass flow (e.g. measured by a mass flow sensor 44 (HFM sensor)), an engine speed measured by a speed sensor, and the like.

The control unit 10 takes over the direct control of the combustion engine 2 also the setting of a boost pressure to a target boost pressure using a boost pressure control. The boost pressure control controls the setting of the charge controller depending on the exhaust gas enthalpies provided and the desired target boost pressure 64 so that an actual boost pressure in a boost pressure section 43 in front of the throttle valve 41 follows the specified target boost pressure as closely as possible.

und dem Verdichtungsverhältnis $\mathrm{\Pi }=\frac{p_{\mathrm{2,}t}}{p_{\mathrm{1,}t}}$

wobei ṁ dem tatsächlichen Massenstrom, pref einem Referenzdruck, auf den das Verdichterkennfeld bezogen ist, und Tref einer Referenztemperatur, auf den das Verdichterkennfeld bezogen ist, entsprechen.When specifying the target boost pressure, a must for the charging device concerned 6 relevant compressor map are taken into account, the operating limits of the compressor 62 observed. Such a compressor map is, for example, in 2 shown and depending on a normalized mass flow ṁ _norm and a compressor speed, a resulting compressor ratio between a pressure on the output side and pressure on the input side of the compressor 62 , The axes of the compressor map correspond to the standardized mass flow ṁ _norm as follows: $${\dot{m}}_{nOrm}=\dot{m}\frac{\sqrt{{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="DE102018207708A1\_0005.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathrm{1,}t}}}{\sqrt{T_{ref}}}\frac{p_{r\mathrm{<figure-callout\; id="1"\; label="e\; f\; p"\; filenames="DE102018207708A1\_0005.png"\; state="\{\{state\}\}">e\; </figure-callout>}f}}{p_{}}$$

and the compression ratio $\mathrm{\Pi }=\frac{{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="DE102018207708A1\_0005.png"\; state="\{\{state\}\}">p</figure-callout>}}_{\mathrm{2,}\mathrm{<figure-callout\; id="1"\; label="t\; p"\; filenames="DE102018207708A1\_0005.png"\; state="\{\{state\}\}">t\; </figure-callout>}}}{p_{}}$

where ṁ corresponds to the actual mass flow, pref a reference pressure to which the compressor map is related and Tref a reference temperature to which the compressor map is related.

The control unit 10 performs a diagnosis of a deviation in the engine system 1 existing mass flow from a measured or modeled mass flow indication. Such a method is based on the flow chart of 3 explained in more detail.

In step S1 is a boost pressure either by direct measurement with a boost pressure sensor or by an indirect measurement, e.g. B. with an intake manifold pressure sensor, and a calculation model of a pressure drop across the charge air cooler 42 and / or the throttle valve 41 determined.

In step S2 the compressor inlet pressure is measured either by direct measurement with a compressor inlet pressure sensor or by measuring the ambient pressure in conjunction with a model of the pressure drop across the air filter 9 determined.

Continue in step S3 a compressor speed using the speed sensor 65 certainly.

Using a compressor map, which in 2 is shown, the standardized mass flow ṁ _norm can now be determined. The compressor map shows the dependencies between a compressor ratio above the compressor for different compressor speeds 62 , ie a ratio between the boost pressure at the outlet side of the compressor 62 , and the compressor inlet pressure p _{1, t} above a standardized mass flow ṁ _norm through the compressor 62 , The normalized mass flow ṁ _norm corresponds to a predetermined reference pressure pref and a Predefined reference temperature Tref standardized mass flow and can be converted to other temperatures and pressures according to the above relationship.

In step S4 can now use the compressor map first the normalized mass flow ṁ _norm and then the mass flow ṁ through the compressor 62 (Compressor mass flow) can be calculated.

The calculation using the compressor map has a high degree of accuracy if the speed lines of the compressor map do not run horizontally, as is the case, for example, for lower mass flows.

In step S5 becomes one with the help of the air mass sensor 44 measured fresh air mass flow rate determined. To do this, it is checked whether the low-pressure exhaust gas recirculation valve 82 is closed, so that the fresh air mass flow is the mass flow through the compressor 62 equivalent. Will in step S5 found that the low pressure exhaust gas recirculation valve 82 is closed (alternative: yes), the procedure with step S6 otherwise the procedure continues with step S8 continued.

In step S6 a deviation between the compressor mass flow determined on the compressor map and the fresh air mass flow is determined.

In step S7 the fresh air mass flow determined by the air mass meter is corrected, in particular by specifying a correction variable which acts multiplicatively, additively or in some other way on the measured value of the fresh air mass flow in order to obtain a corrected fresh air mass flow rate.

In step S8 it is checked whether the high-pressure exhaust gas recirculation valve is closed. If this is the case (alternative: yes), the procedure goes with step S9 otherwise, go to step S1 jumps back. Is the high pressure exhaust gas recirculation valve 72 closed, the engine mass flow corresponds to the compressor mass flow.

wobei p_Saugrohr dem Saugrohrdruck, R einer Gaskonstante für Luft, T_Saugrohr einer Temperatur im Saugrohr, V _H einem Hubraum des Verbrennungsmotors 1, neng einer Motordrehzahl und λ_a einem Luftaufwandsparameter λ_a entsprechen. Der Luftaufwandsparameter λ_a bezeichnet den Luftaufwand zur Umrechnung der Zustandsgrößen des Gases von der Position vor dem Zylinder auf die Position in dem Zylinder, wobei typische Luftaufwandsparameter λ_a Werte von 0,8 bis 0,9 aufweisen können. Der Luftaufwandsparameter λ_a kann sich durch Veränderungen im Saugrohrabschnitt 47 über die Lebensdauer verändern. Dies kann z. B. durch Partikel bewirkt werden, die sich an oder in der Nähe der Zylindereinlassventile ablagern.The engine mass flow through the internal combustion engine 2 or by the cylinders of the internal combustion engine 2 can be calculated with: $${\dot{m}}_{nOrm}=\frac{p_{SauGrOHr}}{R{T}_{SauGrOHr}}{\lambda }_a\frac{V_H}{2}{n}_{enG}$$

in which p _{intake manifold} the intake manifold pressure, R a gas constant for air, T _{intake manifold} a temperature in the intake manifold, V _H a cubic capacity of the internal combustion engine 1 , Neng an engine speed and λ _a an air cost parameter λ _a correspond. The air cost parameter λ _a denotes the air expenditure for converting the state variables of the gas from the position in front of the cylinder to the position in the cylinder, with typical air expenditure parameters λ _a Can have values from 0.8 to 0.9. The air cost parameter λ _a can change due to changes in the intake manifold section 47 change over the lifetime. This can e.g. B. caused by particles that are deposited on or near the cylinder inlet valves.

Assuming that the compressor mass flow has been properly determined using the compressor map, a comparison can be used for the air expenditure parameter λ _a to adapt.

The changes in the air expenditure parameter λ _a Over the lifespan, they mainly come into play at high mass flows or high engine speeds. So in step S9 the air cost parameter λ _a be adjusted according to a deviation between the engine mass flow modeled in this way and the compressor mass flow. The degree of adaptation can be calculated or iteratively by changing the air expenditure parameter λ _a by a correction increment for each detected deviation, in particular above a deviation threshold.

Since the compressor inlet temperature is necessary for the modeling of the compressor mass flow, it is also necessary for the adaptation of the air consumption parameter λ _a The low pressure exhaust gas recirculation valve makes sense to increase accuracy 82 close to improve the determination of the compressor inlet temperature and the compressor inlet pressure using an appropriate model.

The calculation using the compressor map has a high degree of accuracy if the speed lines of the compressor map do not run horizontally, as is the case, for example, for lower mass flows. The area of the compressor map "top right", i.e. at high mass flows and high boost pressures.

Therefore, the steps can be provided S5 to S9 to be carried out only if the engine system 1 is operated in an operating range in which the speed lines, which indicate the course of the compressor ratio Π for a specific speed, do not run horizontally. In addition, the steps can be provided S5 to S9 to be carried out only if the engine system 1 yourself in one stationary state. In particular, the boost pressure should not change, since this can lead to systematic deviations in the mass flows to be adjusted due to the gas storage effects in the charge air cooler volume.

To ensure that component scatter of the compressor 62 , ie deviations between the behavior of the compressor 62 and the compressor map describing the compressor behavior not by correcting the fresh air mass flow sensor or the air expenditure parameter λ _a can be compensated for when the motor system is started up 1 the proper functioning of the fresh air mass flow sensor 44 and the correct parameterization of the air expenditure parameter λ _a be assumed. Thus, by detecting the component scatter using an initial correction variable for the fresh air mass flow and / or for the air expenditure parameter λ _a an initial correction value can be learned. Thus, only deviations with regard to the initially determined correction variable can be taken into account for further adaptations.

It can furthermore be advantageous that the monitoring and adjustment functions described here can actively request the EGR control to close the EGR valves. This is particularly advantageous if the EGR valves would otherwise not be closed or not closed often enough at the relevant operating points.

In addition, it can be advantageous that the function only requests the active closing of the valves if the adjustment functions have not been carried out for a long time. So there are unnecessary emissions from the internal combustion engine 2 largely avoided for these functions. It may also be advantageous to request active closing only if the exhaust gas aftertreatment provides a sufficiently high level of efficiency, in particular e.g. B. the exhaust system is not still cold after starting the engine.

Furthermore, the compressor speed can be corrected by determining the plausibility of the compressor ratio Π and the measured compressor speed in a range of horizontal speed lines (gradient less than a gradient threshold value). At operating points located in this left area of the compressor map, a deviation between the compressor ratio and the compressor speed is recognized instead of a determination of a correction variable for the fresh air mass flow or for the engine mass flow. This deviation can either be due to an incorrect compressor ratio, e.g. B. due to sensor tolerances or increased air filter loading, or due to a changed compressor efficiency. Depending on the application situation, the most likely source of error can be another. However, if this is identified, the deviation between the compressor ratio and the compressor speed can be applied directly to the corresponding sensor or model value or to the entire compressor map using a suitable error model, e.g. B. as an additive or multiplicative correction.

If the deviation between the compressor ratio and the compressor speed is greater than permissible, an error can also be detected and the driver can use suitable signaling, e.g. an optical error display, can be called to a workshop for checking.

It is advantageous to carry out this correction before any other (mass flow) corrections. As a result, the turbocharger specimen scatter is recorded and calculated out for the calculation of the mass flow corrections.

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

• WO 2001/029386 A1 [0004]
• DE 102014201947 B3 [0005]

Claims (15)

Method for operating an engine system (1) with a supercharged internal combustion engine (2), comprising the following steps: - Determining a compression ratio (Π) of a compressor (62) of a charging device (6) of the engine system (1); - Determining (S3) a compressor speed of the compressor (62) with the aid of a speed sensor (65); - Determining (S4) a compressor mass flow (ṁ) using a predetermined compressor map as a function of the compression ratio (Π) and the compressor speed; - Plausibility check of a further mass flow in the engine system (1) depending on the determined compressor mass flow (ṁ); - Operation (S5-S9) of the motor system (1) depending on the plausible further mass flow. Procedure according to Claim 1 , The further mass flow comprises a fresh air mass flow, the plausibility check of the fresh air mass flow being carried out in particular when the low pressure exhaust gas recirculation valve (82) of a low pressure exhaust gas recirculation (8) is closed. Procedure according to Claim 1 , wherein the further mass flow comprises a fresh air mass flow, wherein the closing of the low-pressure exhaust gas recirculation valve (82) is requested to make the fresh air mass flow plausible, wherein the plausibility check of the fresh air mass flow is carried out when the low pressure exhaust gas recirculation valve (82) of a low pressure exhaust gas recirculation (8) is closed is. Procedure according to Claim 2 or 3 Depending on a result of the plausibility check, a correction of the determination of the fresh air mass flow is carried out, in particular by specifying a correction variable which acts multiplicatively or additively on the measured value of the fresh air mass flow in order to obtain a corrected fresh air mass flow rate. Procedure according to one of the Claims 1 to 4 The further mass flow comprises an engine mass flow, the plausibility check of the engine mass flow being carried out in particular when the high-pressure exhaust gas recirculation valve (72) of a high-pressure exhaust gas recirculation (7) is closed. Procedure according to one of the Claims 1 to 4 , wherein the further mass flow comprises an engine mass flow, wherein the closing of the high-pressure exhaust gas recirculation valve (72) is requested to make the engine mass flow plausible, the plausibility check of the engine mass flow being carried out when the high-pressure exhaust gas recirculation valve (72) of a high-pressure exhaust gas recirculation (7) is closed is. Procedure according to Claim 5 or 6 Depending on a result of the plausibility check, a correction of an air expenditure parameter (λ _a ), on which a determination of the engine mass flow is based, is carried out, in particular by specifying a correction variable that acts multiplicatively or additively on the air expenditure parameter (λ _a ). Procedure according to one of the Claims 1 to 7 , wherein the compression ratio (Π) depends on a compressor outlet pressure (p _{2, t} ), which either by direct measurement with a boost pressure sensor (45) or by an indirect measurement of an intake manifold pressure (p _{intake manifold} ), in particular with an intake manifold pressure sensor, and a calculation model of a Pressure drop across a charge air cooler (42) is determined, and wherein the compressor inlet pressure (p _{1, t} ) either by direct measurement with a compressor inlet pressure sensor or by measuring the ambient pressure in connection with a model of the pressure drop across an air filter (9) and in particular an inlet throttle valve ( 41) is determined. Procedure according to one of the Claims 1 to 8th , wherein the compressor map indicates a dependency between a compression ratio (Π) over the compressor (62), a speed of rotation of the compressor (62) and a compressor mass flow normalized to a reference pressure and a reference temperature. Procedure according to one of the Claims 1 to 9 A comparison of the compressor speed with the compressor ratio (Π) is carried out over the compressor map in a range in which the gradient of the course of a compressor ratio (Π) at constant speed does not exceed a predetermined gradient threshold. Procedure according to Claim 10 , this correction being applied before determining a correction quantity for a fresh air mass flow or for an engine mass flow. Device for operating an engine system (1) with a supercharged internal combustion engine (2), the device being designed to: - determine a compression ratio (Π) of a compressor (62) of a supercharger (6) of the engine system (1); - determine a compressor speed of the compressor (62) using a speed sensor (65); - a compressor mass flow (ṁ) depending on a predetermined compressor map to determine the compression ratio (Π) and the compressor speed; - Plausibility check of a further mass flow in the engine system (1) depending on the determined compressor mass flow (ṁ); and - to operate the motor system (1) depending on the plausible further mass flow. Engine system with an internal combustion engine and a device according to Claim 12 , Computer program which is set up to carry out all steps of a method according to one of the Claims 1 to 11 perform. Electronic storage medium on which a computer program is based Claim 14 is saved.

Images