DE10303705A1 - Method for operating an internal combustion engine using direct fuel injection - Google Patents

Abstract

In the method for operating an internal combustion engine (10) which operates with direct fuel injection and is provided with a charging device and has a variable valve drive (31), the valve overlap of the gas exchange valves for full-load operation or at least near-full-load operation of the internal combustion engine is set to stationary setpoint values by adjusting the gas exchange valve control times and with an increased load requirement in the charged operation, the stationary setpoints are dynamically corrected in the direction of higher valve overlap values after charge change TDC. The dynamic correction values are weighted by means of a first factor which is dependent on the pressure difference between the pressure setpoint and the actual pressure (PUT_MES) in the intake duct (11) and by means of a second factor which takes into account the temperature (T_MON) of the exhaust gas catalytic converter (21).

Description

The invention relates to a method for operating a with a charging device and with Direct fuel injection internal combustion engine that has a variable valve train.

Direct injection internal combustion engines (DI, Direct Injection) have great potential for reduction of fuel consumption with relatively low pollutant emissions. In contrast In the case of direct injection, fuel is used for intake manifold injection with high pressure directly into the combustion chambers of the internal combustion engine injected.

For this purpose, injection systems are included central pressure accumulator (common rail) known. In such common rail systems is by means of a high pressure pump from the electronic control unit of the internal combustion engine via pressure sensor and pressure regulator regulated fuel pressure in the manifold (Common Rail) built, the largely independent of speed and injection quantity is available. About an electric controllable injector, the fuel is injected into the combustion chamber. This receives its signals from the control unit. Through the functional separation of pressure generation and injection the injection pressure can be independent largely free from the current operating point of the internal combustion engine chosen become.

It is known for performance and Torque increase of internal combustion engines a supercharger to provide, which increases the amount of charge by pre-compression. there promotes a charger takes the fresh air into the cylinder of the internal combustion engine. With mechanical charging, the compressor is directly from the Internal combustion engine driven (e.g.

Compressor charging) while at an exhaust gas turbocharger with the exhaust gas of the internal combustion engine acted upon turbine (exhaust gas turbine) one in the intake tract of the internal combustion engine drives lying compressor.

This is dynamic with turbocharging Startup behavior partially delayed. The delay arises especially during the transition from part-load operation to full-load operation and is occasionally also referred to as "turbo lag" this transition of the operating point there is an uneven torque output.

Modern internal combustion engines have variable valve train with reduced charge exchange losses single and multi-stage or stepless variability. The The variable valve control of the intake and exhaust valves offers possibility the valve timing within the physical limits of the existing actuator principle (mechanical system, hydraulic System, electrical system, pneumatic system or a combination of the systems mentioned) more or less freely set. Thereby can Consumption savings, lower raw emissions and higher torque can be achieved. A variable camshaft adjustment is for example described in WO 99/43930.

The invention is based on the object specify a procedure by which the operation of a with charging operated and working with direct fuel injection, one variable valve train internal combustion engine, in particular whose response behavior can be improved during transient processes, without doing any harm of the catalytic converter occurs due to excessive temperatures.

This task is accomplished through a process solved, as defined in claim 1.

Advantageous further developments of the inventive method form the subject of the subclaims.

In the method according to the invention becomes the combustion chambers fed to the internal combustion engine Air pre-compressed by means of a supercharger and fuel directly into the combustion chambers injected into the internal combustion engine. The exhaust gas from the internal combustion engine is cleaned by means of an exhaust gas catalytic converter and with the help of a Device can overlap valve the gas exchange valves of the internal combustion engine can be varied. The valve overlap of gas exchange valves for full-load operation or at least operation of the internal combustion engine close to full load is done by setting the gas exchange valve timing to stationary setpoints set. With an increased Load request in the charged operation of the internal combustion engine the stationary setpoints are dynamically corrected in the direction of higher Values. The dynamic correction values are calculated using a first Factor weighted, which depends on the pressure difference between pressure setpoint and actual Pressure in the intake duct is fixed and weighted by means of a second factor, which takes into account the temperature of the catalytic converter. Then be the setpoints corrected in this way are set.

This results in an improved responsiveness of the exhaust gas turbocharger and thus a verb sert response of the internal combustion engine. The start-up behavior delayed in the case of exhaust gas turbocharging, in particular during the transition from part-load operation to full-load operation, sometimes also referred to as “turbo lag”, can thus be reliably prevented.

Further advantages of the method according to the invention tap itself from the description of the embodiment, the following based on the drawing explained becomes. The only figure shows a very simplified block diagram a charged and working with direct fuel injection Internal combustion engine with a variable valve train, in which the inventive method is applied.

In the figure is a supercharged gasoline engine in the form of a block diagram 10 shown with direct fuel injection and an associated exhaust aftertreatment system. Only those components are shown that are necessary for understanding the invention. In particular, the ignition system, the fuel circuit and the cooling circuit have not been shown.

Via an intake duct 11 receives the internal combustion engine 10 the fresh air necessary for combustion. The fresh air supplied flows through an air filter 12 , an air mass meter 13 and an intercooler 14 to a throttle valve block 15 , The throttle valve block 15 includes a throttle valve 16 and a throttle valve sensor, not shown, which determines the opening angle of the throttle valve 16 emits the corresponding signal. With the throttle valve 16 it is, for example, an electromechanically controlled throttle element (E-gas), the opening cross-section of which, in addition to actuation by the driver (driver's request), depends on the operating range of the internal combustion engine via corresponding signals from a control device 17 is adjustable. The air mass meter 13 is used in a so-called air mass-controlled control of the internal combustion engine as a load sensor, its output signal MAF_KGH for further processing of the control device 17 is fed.

The internal combustion engine 10 has a fuel metering device 18 on, the fuel KST is supplied under high pressure and which contains a number of injection valves corresponding to the number of cylinders of the internal combustion engine, which are controlled via corresponding signals from injection output stages which are used, for example, in the electronic control device 17 the internal combustion engine are integrated. Fuel is injected directly into the cylinders of the internal combustion engine via the injection valves 10 injected. The injection valves are advantageously supplied with fuel from a fuel pressure accumulator (common rail). The fuel quantity injected by an injection valve is designated MFF. A pressure sensor 19 on the fuel metering device 18 detects the fuel pressure FUP with which the fuel is injected directly into the cylinders of the internal combustion engine.

The internal combustion engine is on the output side 10 with an exhaust duct 20 connected in which an exhaust gas catalytic converter 21 is arranged. A three-way catalytic converter or a NOx storage catalytic converter or a combination of the two can be provided. The sensors for the exhaust gas aftertreatment include an upstream of the exhaust gas catalytic converter 21 arranged exhaust gas sensor in the form of a lambda probe 22 ,

The temperature of the catalytic converter 21 , more precisely the monolith temperature T_MON is determined by means of a temperature sensor 34 detected in the flow direction of the exhaust gas seen in the front part of the catalytic converter 21 is arranged. The signal T_MON becomes the control device 17 fed for further processing. As an alternative to this, the monolith temperature T_MON can also be calculated using any known exhaust gas temperature model from various input variables, as is the case, for example, in DE 198 36 955 A1 is described.

With the signal λ _{Ex of} the lambda probe 22 the mixture is regulated according to the setpoint specifications. This function is performed by a lambda control device known per se 23 , which preferably into the control device which controls or regulates the operation of the internal combustion engine 17 is integrated. Such electronic control devices 17 , which generally contain one or more microprocessors and which take on a multitude of other control and regulating tasks in addition to fuel injection and ignition control, are known per se, so that in the following only the structure relevant to the invention and its structure How it works is discussed. In particular, the control device 17 with a storage device 24 connected in which, among other things, various characteristic maps and threshold values are stored, the meaning of which will be explained below.

To increase the cylinder charge and thus to increase the performance of the internal combustion engine 10 there is provided a charging device in the form of an exhaust gas turbocharger known per se, the turbine 25 in the exhaust duct 20 is arranged and the via a dashed line in the figure, unspecified shaft with a compressor 26 in the intake duct 11 is in operative connection. The exhaust gases thus drive the turbine 25 and this in turn the compressor 26 on. The compressor 26 takes over the intake and supplies the internal combustion engine 10 a pre-compressed fresh load. The downstream of the compressor 26 horizontal intercooler 14 conducts the heat of compression through the coolant circuit of the internal combustion engine 10 from. As a result, the cylinder charge can be further improved. Parallel to the turbine 25 is a bypass line (bypass line) 27 provided that via a so-called wastegate 28 can be opened to different degrees. As a result, a differently large part of the mass flow from the internal combustion engine on the turbine 25 bypassed so that the compressor 26 of the exhaust gas turbocharger is driven to different extents.

A temperature sensor 29 detects a signal corresponding to the temperature of the internal combustion engine, usually the coolant temperature TCO. A speed sensor 30 detects the speed N of the internal combustion engine. A value PUT_MES for the pressure in the intake duct 11 at a location upstream of the throttle valve 16 and downstream of the charge air cooler 14 is by means of a pressure sensor 33 measured. All of these signals are sent to the control device 17 fed for further processing.

For switching off individual cylinders of the internal combustion engine 10 has the control device 17 An institution 32 , with the help of which the fuel supply to individual cylinders of the internal combustion engine is switched off and released again according to a predetermined switch-off pattern, the so-called switch-off pattern NR_PAT_SCC. Such a device is for example in the EP 0 614 003 B1 described. By switching off the fuel for individual cylinders, the “fired” cylinders, that is to say those cylinders which continue to be supplied with fuel, are utilized to a greater extent, which improves the quality of combustion and gas interaction efficiency. Furthermore, the cylinder deactivation is a method for rapid torque reduction and / or torque limiting.

Furthermore, the internal combustion engine 10 An institution 31 with which the valve overlap of the intake valves and the exhaust valves can be set and changed. Such variable valve controls can be implemented with mechanical systems, hydraulic systems, electrical systems, pneumatic systems or by a combination of the systems mentioned. A distinction can be made between so-called fully variable (stepless) valve trains and systems with valve trains that can be set in stages.

The amount of fuel injection required for combustion MFF becomes more conventional Way from a load parameter, namely the intake air mass MAF_KGH and the speed N calculated and subjected to several corrections (temperature influence, lambda controller, etc.).

A charged, homogeneously operated DI petrol engines offer fresh air in full-load operation to flush directly into the exhaust system. A prerequisite for this is a positive pressure drop between the inlet and outlet side at the time of the charge change OT (top dead center) as well as a sufficient valve overlap VO (valve overlap) between exhaust and intake valve. The valve overlap VO, expressed in ° KW (crankshaft) let yourself in the described embodiment over a Infinitely variable valve timing (IVVT) system. To identify this system, the following are used Parameters preceded by the expression IVVT.

Through the direct injection of Fuel ensures that the start of injection after closing of the exhaust valve. It is only fresh air without fuel flushed to the exhaust side.

The mass flow becomes due to the additional purge air increased by the exhaust gas turbine arranged on the exhaust gas, whereby the achievable maximum performance and dynamic behavior of an exhaust gas turbocharger significantly improve. So in particular for low Engine speeds improve the response behavior of an exhaust gas turbocharger become.

• – Bei einem Lambdawert λ_EX = 1 findet bei Spülluft eine Verbrennung im Zylinder mit einem Lambdawert λ_Cyl < 1 statt. Durch die Verbrennung im Fetten wird die Klopfneigung reduziert.
• – λ_Cyl < 1 bewirkt einen sehr hohen CO- und HC-Anteil im Abgas. Gleichzeitig sorgt der Spülluftanteil für einen hohen Restsauerstoffgehalt und bewirkt so einen internen Sekun därlufteffekt. Die resultierende Abgaszusammensetzung bewirkt eine hohe Exothermie im Abgaskatalysator und beschleunigt so seine Aufheizung.
• – Durch Spülen wird der Restgasanteil im Brennraum und somit die Klopfneigung vermindert. Die Minimierung des Restgasanteils ist bei Betrieb an der Volllast von entscheidender Bedeutung um eine maximale Zylinderfüllung zu erreichen und diese Füllung auch effektiv, d.h. mit günstiger Verbrennungsschwerpunktlage, umzusetzen.
• – Die zusätzliche Spülluftmenge erhöht den Massenstrom durch die Turbine, wodurch bei niedrigen Motordrehzahlen sowohl das Ansprechverhalten, als auch die erreichbare Maximalleistung gesteigert werden können.

When a supercharged internal combustion engine is operated close to full load, a positive pressure difference between the inlet and outlet sides in combination with a corresponding valve overlap VO causes fresh air to be purged to the exhaust side. The amount of purge air increases the throughput through the internal combustion engine without participating in the combustion. The following advantages for operating behavior occur in particular:

• - With a lambda value λ _EX = 1, there is combustion in the cylinder with purge air with a lambda value λ _Cyl <1. Burning in fat reduces the tendency to knock.
• - λ _Cyl <1 causes a very high proportion of CO and HC in the exhaust gas. At the same time, the purge air content ensures a high residual oxygen content and thus creates an internal secondary air effect. The resulting exhaust gas composition causes a high level of exothermicity in the exhaust gas catalytic converter and thus accelerates its heating.
• - By flushing, the residual gas content in the combustion chamber and thus the knock tendency is reduced. The minimization of the residual gas portion is of crucial importance during operation at full load in order to achieve a maximum cylinder charge and to implement this charge effectively, ie with a favorable combustion center.
• - The additional amount of purge air increases the mass flow through the turbine, which means that the response as well as the achievable maximum output can be increased at low engine speeds.

The ratio of the air mass remaining in the cylinder to the total during a work cycle Air mass sucked in is called TE (Trapping Efficiency).

The total air mass drawn in is composed of the air mass M _Cyl that remains in the cylinder and the purge air mass M _Scav , that is, the air mass that is flushed through the cylinder. From the context given above it follows that TE ≤ 1. The larger the purge air _mass M _Scav , the smaller the value for the Trapping Efficiency TE. Ie the air mass meter 13 ( 1 ) measures the total air mass that is sucked in, but then divides via the trapping efficiency TE into an air mass that participates in the combustion and into an air mass that is flushed through the cylinders of the internal combustion engine.

With an IVVT system (Infinitely Variable Valve Timing, stepless adjustment of the camshaft position), the trapping efficiency TE can be steplessly adjusted between a minimum value (maximum purge air) and the value 1 (no purge air, M _Scav = 0) via the intake and exhaust camshaft position ) adjust.

The lambda λ _Ex measured in the exhaust gas does not match the combustion _lambda λ _Cyl due to the scavenging air _mass M _Scav not participating in the combustion. The following relationship applies TE · λ Ex = λ Zyl

The maximum permissible monolith temperature T_MON_MAX of the exhaust gas catalytic converter represents a limitation for the maximum permissible purge air quantity. By means of the lambda value λ _Ex = 1, which is achieved by means of the lambda control device 23 is set and a trapping efficiency TE <1 (positive purge gradient, valve overlap VO> 0) results in a λ _Cyl <1. This means that there is no complete combustion of the fuel in the combustion chamber. A high CO and HC concentration occurs in the exhaust gas. The purge air content in the exhaust gas creates ideal conditions for a post-reaction in the exhaust gas catalytic converter. The high concentrations of the unburned fuel components together with the high residual oxygen content lead to a strong exothermic reaction in the catalytic converter. The monolith temperature T_MON of the exhaust gas catalytic converter can thus rise to critical ranges.

The stationary IVVT setpoint CAM_IN_FL_STAT_SP for the full load operation for the adjustment of the intake camshaft and the stationary IVVT setpoint CAM_EX_FL_STAT_SP for full load operation for the adjustment of the exhaust camshaft are both in view on the achievable full load and the maximum permissible monolith temperature T_MON_MAX Voted. This temperature T_MON_MAX may for reasons of The durability of the catalytic converter is not permanently exceeded become. It is particularly from the material used of the catalytic converter dependent. It is specified by the manufacturer and is for a commercial one Catalytic converter typically 950 ° C.

The values CAM_IN_FL_STAT_SP and CAM_EX_FL_STAT_SP, as well as the resulting valve overlap VO the setpoints for the setting of the gas exchange valves for maximum performance of the internal combustion engine considering the maximum allowable Monolith temperature T_MON_MAX of the catalytic converter, which is in steady-state operation the internal combustion engine permitted are.

The value T_MON_MAX would be exceeded for low speeds (typically N <= 2000 1 / min) with minimal trapping efficiency TE (maximum purge air quantity). Since the maximum purge air volume achieved by maximum valve overlap VO after charge change - TDC (top dead center also exceeds a maximum monolith temperature T_MON_MAX), the stationary IVVT setpoints must be limited. CAM_IN_FL_STAT_SP = CAM_IN_FL_STAT_SP (N, TCO, MAF_KGH) CAM_EX_FL_STAT_SP = CAM_EX_FL_STAT_SP (N, TCO, MAF_KGH)

The stationary setpoints (Set Point, SP) for full load (Full Load, FL) for setting the gas exchange valves, specified in ° KW (crankshaft), are determined depending on the speed N, the coolant temperature TCO and the air mass MAF_KGH and are either in each case a three-dimensional map KF_1 or KF_2 or in several linked maps in the memory device 24 stored.

The monolith temperature T_MON can be determined as a function of basic parameters of the internal combustion engine using any known dynamic temperature model. A temperature model for the monolith temperature T_MON of an exhaust gas catalytic converter is, for example, in FIG DE 199 31 223 C2 described. T_MON = T_MON (N, MAF_KGH, IGA, λ Ex , VS, TCO, NR_PAT_SCC, TE)

• –Drehzahl N der Brennkraftmaschine
• –Luftmasse MAF_KGH,
• –Zündwinkel IGA,
• –Lambdawert im Abgas λ_Ex,
• –Fahrzeuggeschwindigkeit VS (wegen Fahrtwind-Kühlung),
• –Kühlmitteltemperatur TCO,
• –Abschaltpattern PAT_SCC, wenn die Brennkraftmaschine mit einer Einrichtung zur Zylinderabschaltung ausgestattet ist,
• –Trapping Effeciency TE.

Depending on the desired accuracy, all or a selection of the following parameters can be used as input variables for the temperature model:

• –Speed N of the internal combustion engine
• - MAF_KGH air mass,
• –IGA ignition angle,
• –Lambda value in exhaust gas λ _Ex ,
• –Vehicle speed VS (due to airstream cooling),
• –Coolant temperature TCO,
• - Switch-off pattern PAT_SCC, if the internal combustion engine is equipped with a device for cylinder deactivation,
• –Trapping Effeciency TE.

Alternatively, a direct measurement of T_MON in the monolith by means of the temperature sensor is also possible 34 possible.

The stationary IVVT setpoints are through the maximum monolith temperature T_MON_MAX is limited. With a positive Load jump in charged operation (intake manifold pressure> ambient pressure) can, however IVVT setpoints are set briefly, which for reasons of maximum monolith temperature T_MON_MAX are not permanently possible.

Operation with the maximum possible valve overlap VO is possible for a short time (typically for a few seconds) because, due to the thermal inertia of the exhaust system, the value for the maximum monolith temperature T_MON_MAX is only reached and exceeded after a long time. Such short-term operation with increased valve overlap VO is sufficient to improve the turbocharger and engine response behavior. The valve overlap VO is set via a temporary correction of the stationary full load IVVT setpoints CAM_EX_FL_STAT_SP, CAM_IN_FL_STAT SP. The dynamic correction value for the intake valve is called CAM_IN_SP_DYN_COR, the dynamic correction value for the exhaust valve is called CAM_EX_SP_DYN_COR. CAM_IN_SP_DYN_COR = CAM_IN_SP_DYN_COR (N, TCO, MAF_KGH) CAM_EX_SP_DYN_COR = CAM_EX_SP_DYN_COR (N, TCO, MAF_KGH)

These correction values, specified in ° KW (crankshaft), are defined as a function of the speed N, the coolant temperature TCO and the air mass MAF_KGH and are either in a three-dimensional map KF_3 or KF_4, or in several linked maps in the memory device 24 stored.

If there is a positive load jump in the charged mode (intake manifold pressure> ambient pressure), the pressure setpoint specified, for example, by an intake manifold model upstream of the throttle valve PUT SP will jump to the target value, which is higher than the ambient pressure level. The actual pressure PUT MES upstream of the throttle valve 16 however, initially remains at the ambient pressure level and only begins to rise when the compressor 26 about the turbine 25 is driven at a higher speed. If the pressure PUT-MES now reaches the value PUT_SP (PUT_DIF = PUT_SP - PUT_MES the value 0), ie the pressure setpoint has been reached, the dynamic corrections CAM_EX_SP_DYN_COR, CAM_IN_SP_DYN_COR must be reset to zero.

The correction is made via the factors CAM_EX_DYN_COR_FAC and CAM_IN_DYN_COR_FAC.

These factors depend on the pressure difference PUT_DIF = PUT_SP - PUT_MES in the corresponding characteristic maps KF_5 and KF_6 in the memory device 24 stored. CAM_EX_DYN_COR_FAC = CAM_EX_DYN_COR_FAC (PUT_DIF) CAM_IN_DYN_COR_FAC = CAM_IN_DYN_COR_FAC (PUT_DIF), where: CAM_EX_DYN_COR_FAC ∊ [0, 1] CAM_IN_DYN_COR_FAC ∊ [0, 1]

The smaller the pressure difference PUT_DIF = PUT_SP - PUT_MES is the closer the factors CAM_EX_DYN_COR_FRC and CAM_IN_DYN_COR_FAC introduced the value zero.

As already mentioned, it is a longer operation with dynamic corrections CAM_EX_SP_DYN_COR, CAM_IN_SP_DYN_COR for reasons the maximum monolith temperature T_MON_MAX not possible. Depending on the Temperature level in the monolith at the time of the load jump, can it happen that the T_MON_MAX exceeded before the target load value has been reached. In this case, the dynamic corrections CAM_EX_SP_DYN_COR, CAM_IN_SP_DYN_COR early be set to zero. The target load value is also in this case set, but not with the highest possible Dynamics.

The correction is made using the factors CAM_EX_TEMP_COR_FAC and CAM_IN_TEMP_COR_FAC. These factors depend on the monolith temperature T_MON in corresponding maps KF_7 and KF_8 in the memory device 24 stored. CAM_EX_TEMP_COR_FAC = CAM_EX_TEMP_COR_FAC (T_MON) CAM_IN_TEMP_COR_FRC = CAM_IN_TEMP_COR_FAC (T_MON), where: CAM_EX_TEMP_COR_FAC ∊ [0, 1] CAM_IN_TEMP_COR_FAC ∊ [0, 1]

The corrected IVVT setpoint for the exhaust camshaft CAM_EX_FL SP is thus the result of the sum of the stationary setpoint for full load CAM_EX_FL_STAT_SP and the dynamic correction weighted with the correction factor CAM_EX_DYN_COR_FAC and the temperature-dependent correction factor CAM_EX_TEMP_COR_FACD_CY_OR_FACD. CAM_EX_FL_SP = CAM_EX_FL_STAT_SP + CAM_EX_SP_DYN_CORCAM_EX_DYN_COR_FAC_CAM_EX_TEMP_COR_FAC

The corrected IVVT setpoint for the intake camshaft CAM_IN_FL_SP thus results from the sum of the stationary setpoint for full load CAM_IN_FL_STAT_SP and the one that is weighted with the correction factor CAM_IN_SP_DYN_COR_FAC and the temperature-dependent correction factor CAM_IN_TEMP_COR_OR_FD_DYNAMIC_FORM. CAM_IN_FL_SP = CAM_IN_FL-STAT_SP + CAM_IN_SP_DYN_CORCAM_IN_DYN_COR_FACCAM_IN_TEMP_COR_FAC

Is both that of the pressure difference dependent Correction factor, as well as the temperature-dependent correction factor the same Zero (pressure difference P_DIF = zero and T_MON = T_MON_MAX), is also the dynamic correction zero and it becomes the IVVT setpoint on the stationary Setpoint set for Continuous operation possible is.

An IVVT position controller from the facility 31 sets the current intake and exhaust camshaft position to the specified IVVT setpoints. The actual valve overlap VO, which assigns the respective trapping efficiency (TE), results from the measured actual positions CAM_EX, CAM_IN.

The invention was based on a Example explains at the valve overlap VO by means of a so-called IVVT system, i.e. through continuous adjustment both the intake and exhaust camshafts are adjusted becomes.

To carry out the method according to the invention but any device is suitable, with the help of the valve overlap changed can be.

Claims (5)

Method for operating an internal combustion engine ( 10 ) where - the the combustion chambers of the internal combustion engine ( 10 ) air supplied by means of a charging device ( 25 . 26 ) is pre-compressed, - fuel directly into the combustion chambers of the internal combustion engine ( 10 ) is injected, - the exhaust gas of the internal combustion engine ( 10 ) with the help of at least one catalytic converter ( 21 ) is cleaned, - by means of a device ( 31 ) the valve overlap (VO) of the gas exchange valves of the internal combustion engine ( 10 ) can be varied - the valve overlap (VO) of the gas exchange valves for full load operation or at least operation of the internal combustion engine close to full load ( 10 ) is set to stationary setpoints (CAM_IN_FL_STAT_SP, CAM_EX_FL_STAT_SP) by setting the gas exchange valve control times, - with an increased load requirement in the charged operation of the internal combustion engine ( 10 ) a dynamic correction of the stationary setpoints (CAM_IN_FL_STAT_SP, CAM_EX_FL_STAT_SP) takes place, - the dynamic correction values (CAM_IN_SP_DYN_COR, CAM_EX_SP_DYN_COR) by means of a factor (CAM_IN_DYN_COR_FAC, CAM_EX_DYN_COR_FAC, the pressure value, the pressure value, and the pressure value) ) in the intake duct ( 11 ) and weighted by means of a factor (CAM_IN_TEMP_FAC, CAM_EX_TEMP_COR_FAC) which determines the temperature (T_MON) of the catalytic converter ( 21 ) are taken into account, - the setpoints corrected in this way (CAM_IN_FL_SP, CAM_EX_FL_SP) are set. A method according to claim 1, characterized in that the stationary Setpoints (CAM_IN_FL_STAT_SP, CAM_EX_FL_STAT_SP) depend on at least one of the operating sizes of the internal combustion engine Speed (N), coolant temperature (TCO), intake air mass (MAF_KGH) are specified. A method according to claim 2, characterized in that the dynamic correction values (CAM_IN_SP_DYN_COR, CAM_EX_SP_DYN_COR) dependent of at least one of the operating variables of the internal combustion engine Speed (N), coolant temperature (TCO), intake air mass (MAF_KGH) are specified. A method according to claim 1, characterized in that the weighting factors (CAM_IN_DYN_COR_FAC, CAM_EX_DYN_COR_FAC; CAM_IN_TEMP_FAC, CAM_EX_TEMP_COR_FAC) Values between zero and one exhibit. A method according to claim 1, characterized in that the corrected setpoints (CAM_IN_FL_SP, CAM_EX_FL_SP) are calculated according to the following relationship: CAM_IN_FL_SP = CAM_IN_FL_STAT_SP + CAM_IN_SP_DYN_COR · CRM_IN_DYN_COR FAC · CAM IN TEMP COR FAC CAM_EX_FL_SP = CAM_EX_FL_STAT_SP + CAM_EX_SP_DYN_CORCAM_EX_DYN_COR_FACCAM_EX_TEMP_COR_FAC