DE102020112754B4 - Method for operating an internal combustion engine and corresponding internal combustion engine - Google Patents

Abstract

Method for operating an internal combustion engine (2) with at least one cylinder to which fresh gas is supplied by means of at least one inlet valve (4), wherein the amount of fresh gas supplied to the cylinder is determined and an amount of fuel is calculated from the amount of fresh gas based on a predetermined target combustion air ratio and fuel is supplied to the cylinder in accordance with the amount of fuel is supplied and burned with the fresh gas, and wherein after the combustion an actual combustion air ratio and a difference between the actual combustion air ratio and the target combustion air ratio are determined, a correction value for the amount of fuel or the amount of fresh gas being determined from the difference and assigned to an actual value of at least one state variable Internal combustion engine (2) is stored taking into account a dead time determined based on an operating point of the internal combustion engine (2), wherein when the fuel quantity is subsequently calculated, the assigned correction value for the then existing actual value of the at least one state variable is read out and during unsteady operation of the internal combustion engine (2) is used to correct the fuel quantity.

Description

The invention relates to a method for operating an internal combustion engine with at least one cylinder, to which fresh gas is supplied by means of at least one inlet valve, the amount of fresh gas supplied to the cylinder being determined and an amount of fuel being calculated from the amount of fresh gas based on a predetermined target combustion air ratio and fuel being supplied to the cylinder in accordance with the amount of fuel and is burned with the fresh gas, and wherein after the combustion an actual combustion air ratio and a difference between the actual combustion air ratio and the target combustion air ratio are determined. The invention further relates to an internal combustion engine.

For example, US 2015/0 377 170 A1 is known from the prior art. This describes a system for setting an air-fuel parameter.

Furthermore, the publication discloses DE 41 42 155 A1 a digital adaptive control system that calculates and saves a learning value whenever a first condition occurs. The control system has the following functional groups: a learning value memory, which stores the learning values in memory locations that can be addressed via value ranges of at least one operating variable; a learning counter field with one learning counter per memory location of the learning value memory, each learning counter being incremented when a new learning value is written into the assigned memory location; a forced learning device which replaces the learning value in a memory location with a value determined with the help of the learning values of other memory locations if, when a second condition occurs, the status of the assigned learning counter reaches at most a lower limit level and thereby shows that for the value range of operating variables assigned to this memory location there was hardly any learning; and a reset device which, when a cyclically occurring third condition occurs, resets at least those learning counters whose count remains below a predetermined value to an initial level which corresponds at most to the lower limit level.

The publication DE 196 12 453 A1 describes a basic injection time representing a basic injection quantity is precontrolled by specifying a lambda target value, this lambda setpoint value being determined by a coordinated calculation using minimum and maximum selections from a large number of different lambda requirements derived from the operating states of the internal combustion engine. The different lambda requirements are assigned different priorities.

From the publication US 5,924,281 A a system for adjusting a fuel-air ratio for an internal combustion engine is known and in the publication DE 38 25 749 A1 A method for the adaptive control of an internal combustion engine is discussed.

It is the object of the invention to propose a method for operating an internal combustion engine which has advantages over known methods, in particular during unsteady operation or during a load change of the internal combustion engine, enabling efficient operation and/or operation with lower exhaust emissions. In this way, an exhaust gas aftertreatment device can be relieved.

This is achieved with a method for operating an internal combustion engine with the features of claim 1. It is provided that a correction value for the amount of fuel or the amount of fresh gas is determined from the difference and is stored in association with an actual value of at least one state variable of the internal combustion engine, taking into account a dead time determined based on an operating point of the internal combustion engine, with the associated one being calculated when the amount of fuel is subsequently calculated Correction value for the then existing actual value of the at least one state variable is read out and used to correct the fuel quantity during transient operation of the internal combustion engine.

The method is used to operate the internal combustion engine. The internal combustion engine is intended and designed, for example, to drive a motor vehicle. In this case, the internal combustion engine serves to provide a drive torque aimed at driving the motor vehicle. The internal combustion engine has at least one cylinder. Of course, the internal combustion engine can also have several cylinders. In this case, the at least one cylinder is part of these several cylinders. If the cylinder or at least one cylinder is discussed in the context of this description, the statements are equivalent. If the internal combustion engine has multiple cylinders, the designs for the cylinder or the at least one cylinder can also preferably be transferred to each of the multiple cylinders.

During operation of the internal combustion engine, fresh gas is supplied to the cylinder via the at least one inlet valve. The fresh gas contains at least fresh air, which is taken from an external environment of the internal combustion engine. Fresh air contains oxygen. Optionally, the fresh gas can contain exhaust gas. In this case, the internal combustion engine has exhaust gas recirculation, by means of which exhaust gas generated by the internal combustion engine is fed back to it via the inlet valve after it has been discharged from the cylinder.

A target combustion air ratio is set on the internal combustion engine, with which the internal combustion engine or the at least one cylinder is operated. During operation of the internal combustion engine, a certain amount of fresh gas is supplied to the cylinder. This is determined, for example, from a target power that is set on the internal combustion engine. After supplying the amount of fresh gas into the cylinder and determining the amount of fresh gas, the amount of fuel that must be supplied to the cylinder to achieve the target combustion air ratio is calculated from the amount of fresh gas. Fuel is then supplied to the cylinder according to this calculated amount of fuel and burned together with the fresh gas.

The resulting exhaust gas is removed from the cylinder, in particular via at least one exhaust valve. After the fuel has been burned with the fresh gas, in particular after the exhaust gas has been ejected from the cylinder, the actual combustion air ratio is determined based on the exhaust gas. For this purpose, a corresponding sensor, for example a lambda sensor, is preferably provided, which in particular is flowed against and/or overflowed by the exhaust gas. The difference between the actual combustion air ratio and the target combustion air ratio is subsequently determined.

For example, it can now be provided to carry out lambda control of the internal combustion engine based on the difference. This serves to regulate the actual combustion air ratio to the target combustion air ratio. The difference between these represents the control difference. The quantity of fuel is preferably used as the manipulated variable for lambda control. This means that as part of the lambda control, the amount of fuel is regulated in such a way that the actual combustion air ratio changes in the direction of the target combustion air ratio or corresponds to it. This procedure is particularly useful during stationary operation of the internal combustion engine, i.e. while the operating point of the internal combustion engine remains constant. The operating point is characterized, for example, by the speed of the internal combustion engine and/or the torque or drive torque provided by the internal combustion engine.

However, particularly in the case of unsteady operation of the internal combustion engine, during which the operating point changes, a different approach is preferred according to the invention. According to this, the correction value for the amount of fuel or the amount of fresh gas is determined from the difference between the actual combustion air ratio and the target combustion air ratio. The correction value here is to be understood as a value with which the amount of fuel calculated from the amount of fresh gas or the determined amount of fresh gas must be changed in order to change the actual combustion air ratio in the direction of the target combustion air ratio, in particular in such a way that the actual combustion air ratio corresponds to the target combustion air ratio. The correction value determined in this way is assigned to the actual value of the at least one state variable of the internal combustion engine and stored together with it. In other words, after saving, the correction value is assigned to the actual value of the state variable.

According to the invention, this is done in such a way that a dead time within the internal combustion engine is taken into account. In addition, an exhaust gas running time can be taken into account. The correction value is therefore preferably not assigned to the actual value that is present after the correction value has been determined. Rather, it is assigned to the actual value that existed at the time at which the amount of fresh gas and/or the amount of fuel was supplied to the cylinder and which thus led to the difference between the actual combustion air ratio and the target combustion air ratio. For example, the actual value is temporarily stored until the correction value to be assigned to it is determined. Only then, i.e. with a time delay, is the correction value assigned to the actual value and saved together with it. The dead time and - optionally - the exhaust gas transit time are determined based on the operating point of the internal combustion engine. The operating point is characterized in particular by the speed and/or the torque of the internal combustion engine.

When the fuel quantity is subsequently calculated, for example in a subsequent working cycle of the internal combustion engine, the correction value for the then existing actual value of the state variable is read out and subsequently used to correct the fuel quantity. In this respect, when the fuel quantity is subsequently calculated, it is first checked whether there is already a correction value for the actual value of the state variable was saved. If this is the case, it is read and used to correct the fuel quantity. If no correction value was previously stored for the actual value of the state variable, the correction value is set to a standard value, for example zero.

The correction value is then used to correct the fuel quantity. Subsequently, as already explained, the actual combustion air ratio is determined and from this the difference between the actual combustion air ratio and the target combustion air ratio is calculated. If the actual combustion air ratio deviates from the target combustion air ratio, i.e. if the difference is different from zero, the correction value for the fuel quantity is determined from the difference, in particular based on the previously saved correction value, and (again) saved with assignment to the actual value of the state variable . In this respect, the correction value for the respective actual value of the state variable is preferably determined iteratively.

By relating the correction value to the actual value of the state variable, the operation of the internal combustion engine is optimized in a situation-related manner. If the internal combustion engine is operated for a while, correction values are subsequently available for numerous different actual values of the state variable, so that the fuel quantity can be corrected in a targeted manner for different actual values of the state variable. This results in particularly efficient and/or low-emission operation of the internal combustion engine, particularly during transient operation. The procedure described is particularly preferably used, in particular only if a gradient of the speed of the internal combustion engine is different from zero and/or a gradient of the torque provided by the internal combustion engine is different from zero. Otherwise, the conventional lambda control already mentioned above can be carried out. This further increases the efficiency of the internal combustion engine.

The correction value is particularly preferably saved on a cylinder-specific basis. This means that the correction value is stored for exactly the cylinder for which it was determined. Correcting the fuel quantity is also carried out on a cylinder-specific basis, namely with the correction value that has already been stored for the respective cylinder. In this way, structural tolerances of the internal combustion engine can be compensated for in a particularly effective manner.

A further development of the invention provides that the actual combustion air ratio is determined using a lambda sensor. The lambda sensor is arranged in an exhaust pipe of the internal combustion engine, via which the exhaust gas generated by the internal combustion engine, in particular all of the exhaust gas generated by the internal combustion engine, is discharged towards an external environment. In terms of flow, the lambda sensor is arranged between the internal combustion engine and an end pipe of the exhaust pipe, via which the exhaust gas is discharged into the external environment of the internal combustion engine. The lambda probe is preferably arranged in such a way that the exhaust gas flowing through the exhaust line flows against it and/or overflows it. This results in a particularly precise determination of the actual combustion air ratio. In particular, the actual combustion air ratio is measured using the lambda sensor; There is therefore no pure modeling of the actual combustion air ratio.

A further development of the invention provides that the at least one cylinder is part of several cylinders of the internal combustion engine and the actual combustion air ratio is determined for each cylinder, in particular in a common exhaust pipe that is fluidly connected to the several cylinders. The internal combustion engine has several cylinders, which include the above-mentioned cylinder or at least one cylinder. The actual combustion air ratio is determined for each cylinder. This means that for each combustion that occurs in one of the cylinders, the actual combustion air ratio is subsequently determined for exactly this combustion.

For example, this is done by measuring using the lambda sensor, with the exhaust gas emitted from the internal combustion engine being assigned to the respective combustion in the respective cylinder in time. For this purpose, for example, the plurality of cylinders, in particular all cylinders of the internal combustion engine, are fluidly connected to the same exhaust pipe, which in this respect can be referred to as a common exhaust pipe. The lambda probe is assigned to the common exhaust pipe, in particular it projects into it or is arranged in it. Accordingly, the cylinder-specific determination of the actual combustion air ratio can be carried out in a simple manner.

The invention provides that the correction value is used to correct the amount of fuel during transient operation of the internal combustion engine, in particular only during transient operation. This has already been pointed out above. The procedure described Determining the correction value and assigning the correction value to the actual value of the state variable is beneficial to the efficiency of the internal combustion engine, especially during transient operation, because during transient operation the usual lambda control does not have the desired effect or only partially develops it.

Rather, the amount of fuel determined by the lambda control always lags behind the amount of fuel actually required because the lambda control always includes a dead time, which is determined, for example, by the time that the exhaust gas requires to flow through the path between the cylinder and the lambda sensor. The method described, on the other hand, is almost independent of such a dead time because the determined correction value, in particular the correction value determined for each cylinder, is always stored associated with the actual value of the state variable.

A further development of the invention provides that, at least during stationary operation of the internal combustion engine, a global correction value is determined by means of a lambda control, which is used to correct the amount of fuel independently of the actual value of the state variable. The use of lambda control has already been pointed out. The lambda control is preferably carried out at least during stationary operation of the internal combustion engine. However, it particularly preferably also takes place during the transient operation of the internal combustion engine and is therefore permanent.

With the help of the lambda control, the global correction value is determined, with which the fuel quantity calculated from the fresh gas quantity is corrected. For example, it is provided to first correct the fuel quantity with the global correction value and only then with the correction value that was read out for the currently existing actual value of the state variable. In this respect, a two-stage correction of the fuel quantity is carried out in order to achieve a particularly precise result. This results in particularly efficient and/or low-emission operation of the internal combustion engine.

A further development of the invention provides that at least one of the following state variables is used as at least one state variable: speed of the internal combustion engine, torque of the internal combustion engine, speed gradient of the speed, torque gradient of the torque, throttle valve position and throttle valve position gradient. The speed and/or the torque describe the operating point of the internal combustion engine, as already explained. They enable the correction value to be assigned in a particularly simple manner.

Additionally or alternatively, the speed gradient or the torque gradient can be used as a state variable. The speed gradient means the gradient of the speed over time and the torque gradient means the gradient of the torque over time. The speed gradient and the torque gradient enable a particularly precise description of the current state of the internal combustion engine during transient operation. The throttle valve position describes a throttling of the internal combustion engine. For example, the throttle valve position is specified in the form of a throttle valve angle.

In principle, an actual value and/or a setpoint can be used for each of the state variables mentioned. The setpoint is to be understood as meaning the value that is set for the respective state variable on the internal combustion engine. The actual value is the value that occurs during operation of the internal combustion engine.

Of course, another state variable can also be used in addition to or as an alternative to the state variables already mentioned. Examples of such state variables include temperature, in particular an ambient temperature, a pressure, in particular an ambient air pressure, and a fuel composition. The use of the actual value of one of the parameters mentioned enables particularly efficient and/or low-emission operation of the internal combustion engine.

A further development of the invention provides that the correction value is stored associated with the actual values of several state variables. The correction value is therefore not only stored as assigned to the actual value of a single state variable. Rather, it is assigned to several actual values, with the actual values being available for state variables that are separate from one another. For example, two or more of the above-mentioned state variables are used as state variables. The correction value is preferably stored in a multi-dimensional data field which is spanned by the actual values of the several state variables.

The correction value is therefore not stored separately assigned to the actual values, but is assigned to the actual values together. This is done in such a way that the correction value subsequently results as a function of the actual values of the several state variables. In other words, the amount of fuel is subsequently calculated the assigned correction value for the then existing actual values of the several state variables is read out and used to correct the fuel quantity. This further improves the efficiency of the internal combustion engine.

A further development of the invention provides that the correction value for the fuel quantity is determined iteratively. This means that - as already explained - during operation of the internal combustion engine to calculate the amount of fuel, the amount of fresh gas is first determined and the amount of fuel is calculated from this. It is then checked whether the correction value has already been stored for the current actual value of the state variable. If this is the case, it is read and used to correct the fuel quantity. If no correction value is yet stored, the correction value is, for example, set to a standard value and also used to correct the fuel quantity.

The actual combustion air ratio occurring during combustion in the respective cylinder is then determined and the difference to the target combustion air ratio is determined. The correction value is determined (again) from the difference and stored for the actual value of the state variable for which the correction value was previously read out. The correction value read out is therefore overwritten with the newly determined correction value, resulting in a gradual correction of the fuel quantity. The accuracy of the determined fuel quantity increases over time.

A further development of the invention provides that the amount of fresh gas is measured using a mass flow sensor or calculated using a model, whereby if the actual combustion air ratio and the target combustion air ratio match, a corrected amount of fresh gas is calculated from the amount of fuel and the correction value for the amount of fresh gas is calculated from the determined amount of fresh gas and the corrected amount of fresh gas is calculated and saved. Basically, as part of determining the amount of fresh gas, this is measured or calculated. The procedure for correcting the fuel quantity already explained above is then carried out until the difference between the actual combustion air ratio and the target combustion air ratio is equal to zero or at least an absolute value of the difference is smaller than a limit value.

In this case, it is assumed that the correction of the fuel quantity has been completed, so that the correction value for the fuel quantity eliminates or at least largely eliminates all deviations for the actual value of the state variable. If the stated condition is met, the corrected fresh gas quantity is calculated from the fuel quantity and the target combustion air ratio, in particular from the corrected fuel quantity. The correction value is then calculated from the originally determined amount of fresh gas and the corrected amount of fresh gas, which is in particular in the form of a difference between the determined amount of fresh gas and the corrected amount of fresh gas or vice versa. Then the correction value for the amount of fresh gas is stored analogously to the correction value for the amount of fuel and assigned to the actual value of the at least one state variable of the internal combustion engine.

Preferably, when the amount of fresh gas is subsequently determined, it is corrected with the correction value for the respective actual value of the state variable. When determining the correction value for the amount of fresh gas, it is assumed that a correction of the amount of fuel is no longer necessary. Accordingly, the correction value for the fuel quantity is reset, namely to the standard value, for example to zero.

If the actual combustion air ratio subsequently deviates from the target combustion air ratio despite the corrected fresh gas quantity, the correction value for the fuel quantity is first determined in the manner described and only when the actual combustion air ratio and target combustion air ratio match, at least within the tolerance, is the correction value for the fresh gas quantity determined, in particular determined again, and stored. This procedure enables particularly efficient and/or low-emission operation of the internal combustion engine.

The invention further relates to an internal combustion engine with at least one cylinder, in particular for carrying out the method according to one or more of the preceding claims, wherein the internal combustion engine is intended and designed to supply fresh gas to the cylinder by means of at least one inlet valve, the amount of fresh gas supplied to the cylinder being determined and a fuel quantity is calculated from the quantity of fresh gas based on a predetermined target combustion air ratio and fuel is supplied to the cylinder in accordance with the quantity of fuel and is burned with the fresh gas, and wherein after the combustion an actual combustion air ratio and a difference between the actual combustion air ratio and the target combustion air ratio are determined.

It is provided that the internal combustion engine is further designed to operate from the difference renz to determine a correction value for the fuel quantity and, taking into account a dead time determined based on an operating point of the internal combustion engine, to store it assigned to an actual value of at least one state variable of the internal combustion engine, wherein when the fuel quantity is subsequently calculated, the assigned correction value for the then existing actual value of the at least one state variable is read out and is used to correct the amount of fuel during transient operation of the internal combustion engine.

The advantages of such an approach have already been pointed out. Both the internal combustion engine and the method for operating it can be further developed in accordance with the statements in this description, so that reference is made to the corresponding statements.

• 1 eine schematische Darstellung einer Antriebseinrichtung mit einer Brennkraftmaschine,
• 2 ein Diagramm, in welchem eine Sollluftmenge, eine Istluftmenge, eine Istkraftstoffmenge und ein Verbrennungsluftverhältnis vor einer Optimierung über der Zeit aufgetragen sind,
• 3 ein Diagramm, in welchem die genannten Größen während einer Optimierung über der Zeit aufgetragen sind, sowie
• 4 ein Diagramm, in welchem die genannten Größen nach Abschluss der Optimierung über der Zeit aufgetragen sind.

The invention is explained in more detail below using the exemplary embodiments shown in the drawing. This shows:

• 1 a schematic representation of a drive device with an internal combustion engine,
• 2 a diagram in which a target air quantity, an actual air quantity, an actual fuel quantity and a combustion air ratio are plotted over time before optimization,
• 3 a diagram in which the variables mentioned are plotted over time during an optimization, as well as
• 4 a diagram in which the variables mentioned are plotted over time after the optimization has been completed.

The 1 shows a schematic representation of a drive device 1, for example for a motor vehicle. The drive device 1 has an internal combustion engine 2 to provide a drive torque. In the exemplary embodiment shown here, the internal combustion engine 2 has a plurality of cylinders, each with a combustion chamber 3. Each of the cylinders has at least one intake valve 4 and at least one exhaust valve 5.

Fresh gas can be supplied to the respective cylinder through each of the inlet valves 5, whereas exhaust gas can escape from the corresponding cylinder through each of the outlet valves 5, namely in the direction of an exhaust pipe 6. During operation of the drive device 1 or the internal combustion engine 2, this generates exhaust gas, which via the exhaust pipe 6 is discharged towards an external environment. For this purpose, the exhaust gas is first supplied to the exhaust gas aftertreatment device 7 and then discharged into the outside environment, for example via an end pipe 8 following the exhaust gas line 6.

During operation of the internal combustion engine 2, each of the cylinders is supplied with fresh gas via the respective inlet valve 4, the amount of fresh gas supplied to the respective cylinder being determined and an amount of fuel being calculated from the amount of fresh gas based on a predetermined target combustion air ratio. Fuel is then supplied to the corresponding cylinder according to the fuel quantity and burned with the fresh gas. After combustion, an actual combustion air ratio is determined. In addition, a difference between the actual combustion air ratio and the target combustion air ratio is calculated. A correction value for the amount of fuel or the amount of fresh gas is determined from the difference and stored with association with an actual value of at least one state variable of the internal combustion engine 2.

When the fuel quantity is subsequently calculated, the assigned correction value for the then existing actual value of the state variable is read out and used to correct the fuel quantity. This is done iteratively until the actual combustion air ratio corresponds to the target combustion air ratio, at least taking a tolerance into account. If the stated condition is met, a corrected fresh gas quantity is calculated from the uncorrected fuel quantity and the target combustion air ratio.

From this corrected amount of fresh gas and the determined amount of fresh gas, a correction value for the amount of fresh gas is determined and stored, namely again assigned to the actual value of the at least one state variable of the internal combustion engine 2. At the same time, the correction value for the amount of fuel for this actual value can be reset, for example to a standard value . Using the correction value for the amount of fresh gas, the amount of fresh gas introduced into the respective cylinder can be determined with high accuracy from a measured amount of fresh gas or calculated using a model.

The 2 shows a diagram in which a curve 9 shows a target fresh gas quantity over time t. The target fresh gas quantity depends, for example, on a target power of the internal combustion engine 2 and has an increase in the exemplary embodiment shown here. A curve 10 shows an actual amount of fresh gas over time t. It becomes clear that the actual amount of fresh gas lags behind the target amount of fresh gas. Furthermore, a curve 11 shows the calculated amount of fuel and a curve 12 shows the actual value combustion air ratio. It turns out that the actual combustion air ratio has a strong deviation from its mean value during a time window in the area of the increase in the target air quantity. This deviation results in particular from an error in determining the amount of fresh gas that the curve 10 shows.

The 3 shows a diagram which again shows the target fresh gas quantity, the actual fresh gas quantity, the fuel quantity and the actual combustion air ratio over time with the curves 9, 10, 11 and 12. The curves shown result from a point in time at which correction values for the fuel quantity have already been calculated and saved. The saved correction value is the basis for the curves shown here. It becomes clear that the courses 9 and 10 are related to the courses 9 and 10 of the 2 to match. However, the amount of fuel changes, as can be seen from curve 11. This resulted in a smaller deviation of the actual combustion air ratio from its mean value, as illustrated by curve 12.

The 4 again shows a diagram in which the courses 9, 10, 11 and 12 are shown according to the definition above. The curves shown occur in the event that the correction value for the fuel quantity has been determined with such precision that the actual combustion air ratio corresponds to the target combustion air ratio, at least taking a certain tolerance into account. In this case, as already explained, the corrected amount of fresh gas is calculated from the corrected amount of fuel, so that the correction value for the amount of fresh gas is available and can be used to correct it.

This correction can be seen in the curve 10. The curve 10 of the fresh gas quantity is used as the basis for the calculation of the fuel quantity, as shown by the curve 11. Due to the corrected amount of fresh gas, the actual combustion air ratio results in a curve which corresponds to its mean value or fluctuates around its mean value with almost no deviations. This is shown by course 12.

With the described internal combustion engine 2 or the described method for operating the internal combustion engine 2, an extremely high level of accuracy is achieved in determining the amount of fuel required and the amount of fresh gas introduced into the cylinders. In this respect, extremely efficient and/or low-emission operation of the internal combustion engine 2 is carried out.

REFERENCE SYMBOL LIST:

1

Drive device

2

Internal combustion engine

3

combustion chamber

4

Inlet valve

5

outlet valve

6

Exhaust pipe

7

Exhaust gas aftertreatment device

8th

tailpipe

9

Course

10

Course

11

Course

12

Course

Claims (9)

Method for operating an internal combustion engine (2) with at least one cylinder to which fresh gas is supplied by means of at least one inlet valve (4), wherein the amount of fresh gas supplied to the cylinder is determined and an amount of fuel is calculated from the amount of fresh gas based on a predetermined target combustion air ratio and fuel is supplied to the cylinder in accordance with the amount of fuel is supplied and burned with the fresh gas, and wherein after the combustion an actual combustion air ratio and a difference between the actual combustion air ratio and the target combustion air ratio are determined, a correction value for the amount of fuel or the amount of fresh gas being determined from the difference and assigned to an actual value of at least one state variable Internal combustion engine (2) is stored taking into account a dead time determined based on an operating point of the internal combustion engine (2), wherein when the fuel quantity is subsequently calculated, the assigned correction value for the then existing actual value of the at least one state variable is read out and during unsteady operation of the internal combustion engine (2) is used to correct the fuel quantity. Procedure according to Claim 1 , whereby the actual combustion air ratio is determined using a lambda sensor. Method according to one of the preceding claims, wherein the at least one cylinder is part of several cylinders of the internal combustion engine (2) and the actual combustion air ratio is determined for each cylinder. Method according to one of the preceding claims, wherein at least during stationary operation of the internal combustion engine (2) a global correction value is determined by means of a lambda control, which is used to correct the amount of fuel independently of the actual value of the state variable. Method according to one of the preceding claims, wherein at least one of the following state variables is used as at least one state variable: speed of the internal combustion engine (2), torque of the internal combustion engine (2), speed gradient of the speed, torque gradient of the torque, throttle valve position and throttle valve position gradient. Method according to one of the preceding claims, wherein the correction value is stored associated with the actual values of several state variables. Method according to one of the preceding claims, wherein the correction value for the fuel quantity is determined iteratively. Method according to one of the preceding claims, wherein the amount of fresh gas is measured by means of a mass flow sensor or calculated using a model, whereby if the actual combustion air ratio and the target combustion air ratio match, a corrected amount of fresh gas is calculated from the amount of fuel and the correction value for the amount of fresh gas is calculated from the determined amount of fresh gas and the corrected amount of fresh gas is calculated and saved. Internal combustion engine (2) with at least one cylinder, in particular for carrying out the method according to one or more of the preceding claims, wherein the internal combustion engine (2) is intended and designed to supply fresh gas to the cylinder by means of at least one inlet valve, the amount of fresh gas supplied to the cylinder being determined and an amount of fuel is calculated from the amount of fresh gas based on a predetermined target combustion air ratio and fuel is supplied to the cylinder in accordance with the amount of fuel and burned with the fresh gas, and wherein after the combustion an actual combustion air ratio and a difference between the actual combustion air ratio and the target combustion air ratio are determined, the internal combustion engine (2 ) is further designed to determine a correction value for the fuel quantity from the difference and to store it associated with an actual value of at least one state variable of the internal combustion engine (2), taking into account a dead time determined based on an operating point of the internal combustion engine (2), with a subsequent calculation of the fuel quantity the assigned correction value for the then existing actual value of the at least one state variable is read out and used to correct the fuel quantity during transient operation of the internal combustion engine (2).

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