EP1003960B1 - Method for operating an internal combustion engine - Google Patents

Abstract

The invention relates to an internal combustion engine (1), especially for a motor vehicle. The internal combustion engine (1) is provided with an injection valve (8) by means of which fuel can be injected directly into a combustion chamber (4) either in a first operating mode during a compression stage or in a second operating mode during a suction stage. The invention also provides for a control device (16) for switching between the two operating modes and for carrying out a control and/or adjustment, differently for each operating mode, of the operating variables influencing the actual torque of the internal combustion engine (1) in accordance with a set-point torque. A change in the actual torque occurring during switching from mode into another is detected by the control device (16) and at least one of the operating parameters is influenced by the control device (16) in accordance with said change.

Description

State of the art

The invention relates to a method for operating a Internal combustion engine, in particular of a motor vehicle, at the fuel either in a first mode of operation a compression phase or in a second operating mode directly into a combustion chamber during an intake phase is injected in between the two Operating modes is switched, and in which the the actual moment influencing the internal combustion engine Operating variables depending on a target torque in the two operating modes controlled differently and / or be managed. Furthermore, the invention relates to a Internal combustion engine, in particular for a motor vehicle, with an injector, with fuel in either one first operating mode during a compression phase or in a second operating mode directly during an intake phase is injectable into a combustion chamber, and with a Control unit for switching between the two Operating modes and for different control and / or Regulation in the two operating modes of the actual moment of Operating variables influencing internal combustion engine in Dependence on a target torque. (See WO-A-985 1920 and / or WO-A-9 901 654).

Such systems for the direct injection of fuel in the combustion chamber of an internal combustion engine are general known. It is the first operating mode so-called shift operation and as a second operating mode so-called homogeneous operation. The Shift operation is particularly important for smaller loads used during the homogeneous operation at larger, at the Internal loads applied to the internal combustion engine.

In shift operation, the fuel is used during the Compression phase of the internal combustion engine in the combustion chamber injected in such a way that a Cloud of fuel in the immediate vicinity of a spark plug located. This injection can be different Way. So it is possible that the injected Fuel cloud is already during or immediately after the injection is at the spark plug and from this is ignited. It is also possible that the injected cloud of fuel through a charge movement the spark plug is led and then ignited. at the two combustion processes are not uniform Fuel distribution before, but a stratified charge.

The advantage of shift operation is that there a very small amount of fuel smaller loads carried out by the internal combustion engine can be. However, larger loads cannot the shift operation can be fulfilled.

In homogeneous operation intended for such larger loads the fuel is during the intake phase of the Internal combustion engine injected so that a swirl and thus a distribution of the fuel in the combustion chamber can still be done easily. To that extent corresponds to Homogeneous operation such as the operation of Internal combustion engines in the conventional way Fuel is injected into the intake pipe. If necessary can operate even with smaller loads be used.

In shift operation, the throttle valve becomes the Combustion chamber leading intake pipe wide open and the Combustion is essentially only through the Fuel mass to be injected controlled and / or regulated. In homogeneous operation, the throttle valve is in Dependent on the requested moment opened or closed and the fuel mass to be injected is in Controlled depending on the intake air mass and / or regulated.

In both operating modes, i.e. in shift operation and in Homogeneous operation, the fuel mass to be injected in Dependence on a number of others Company sizes on one with regard to Saving fuel, reducing emissions and the like optimal value controlled and / or regulated. The control and / or regulation is in the two operating modes differently.

It is necessary to remove the internal combustion engine from the Shift operation in homogeneous operation and back again switch. The throttle valve is in shift operation is wide open and thus largely dethrones the air is supplied, the throttle valve is only in homogeneous operation partially opened, reducing the intake of Air. Especially when switching from shift operation to homogeneous operation must be the ability of the Combustion chamber leading intake pipe are taken into account, air save. If this is not taken into account, it can Switching to an increase in that of the internal combustion engine given moments.

The object of the invention is a method for operating to create an internal combustion engine with which a improved switching between operating modes possible is.

This task is initiated in a procedure mentioned type or in an internal combustion engine of initially mentioned type solved according to the invention in that a change in the actual moment during a Switching operation is determined, and that depending of which at least one of the operating variables is influenced.

Based on the determination of changes in the actual torque during the switching process it is possible Unresting or jerking during switching detect. After a jerk is detected, the Influencing operational parameters of uneven running be counteracted. Overall, it is possible Unrest or jerking while switching from that Homogeneous operation in shift operation or vice versa avoid. The switching operations between the two Operating modes are thus particularly with regard to increased smoothness and thus increased comfort improved.

In an advantageous development of the invention the change in the actual torque depending on the detected speed of the internal combustion engine. In order to is achieved with the help of the already existing Speed sensor a change in the actual torque and thus a Jerky or the like can be detected. additional Sensors or other additional components are thus not mandatory.

In a first advantageous embodiment of the invention becomes an expected depending on the target torque Speed determined, and it is the expected speed with the detected speed of the internal combustion engine compared. It speed prediction is carried out. It will calculates which speed should be available, if there is no uneven running. Based on a comparison of this expected speed with the actual engine speed will then determines whether jerking occurs during the switching process is present or not.

It is particularly advantageous if at least one of the Operating variables of the internal combustion engine is influenced when the detected speed by more than a predetermined Speed difference deviates from the expected speed. The expected speed deviates from the actually recorded speed Speed decreases significantly, this leads to uneven running closed during the switching process This then has to Consequence that the actual moment of the internal combustion engine over a of company sizes in the sense of a reduction of Torque change is affected.

Furthermore, it is particularly advantageous if none Influencing is carried out when several successive speed differences an approximately constant Show course. Such is approximately constant History, it means that the on the Internal combustion engine has changed load. For example, due to an incline or the like, So a change in driving resistance, has in this So if the torque changes continuously, e.g. elevated. So there is no jerking and no uneven running before, so that no countermeasures are taken have to.

In a second advantageous embodiment of the invention are from the detected speed of the internal combustion engine at least two speed gradients are determined, and there are two of the speed gradients are compared. So it will change the actual speed of the Internal combustion engine monitored. This is through the Calculation of the speed gradient in a simple way reached. Additional components or the like are included not mandatory.

It is particularly advantageous if at least one of the Operating variables of the internal combustion engine is influenced when the two speed gradients have a discontinuous course exhibit. The inconsistent course of the speed gradient is thus regarded as an uneven running or a jerking during the Switching process interpreted. Load changes or the like have an approximately constant course of Speed gradients result, so that in this case not is judged to be jerky. Only when recognized Unrest is then countermeasures to reduce the Stuttering caught during the switching process.

In an advantageous development, the Influencing one of the operating variables adaptively carried out. So there is a permanent correction of the Switchover. This makes it possible, for example Changes in the internal combustion engine over its runtime, in particular signs of wear and the like compensate. It is also possible to deviate between different internal combustion engines of the same type balance during commissioning.

In a further advantageous development of the Invention is influencing one of the operating parameters only carried out for the next switching process. In order to it is achieved that the calculations according to the invention can be carried out between two switching processes, so that there is sufficient time for this.

It is particularly advantageous if in the first Operating mode the injected fuel mass in particular is influenced in the sense of an increase. It is also advantageous if the ignition angle in the second operating mode or the ignition point in particular in the sense of a Late adjustment is affected. Through these measures it is possible, if a running irregularity is detected during the Switching process to the actual torque of the internal combustion engine influence and thus reduce the uneven running. In particular, these two measures Operating modes approximated at the time of switching.

Figur 1

zeigt ein schematisches Blockschaltbild eines Ausführungsbeispiels einer erfindungsgemäßen Brennkraftmaschine eines Kraftfahrzeugs,

Figur 2

zeigt ein schematisches Ablaufdiagramm eines Ausführungsbeispiels eines erfindungsgemäßen Verfahrens zum Betreiben der Brennkraftmaschine der Figur 1,

Figur 3

zeigt ein schematisches Zeitdiagramm von Signalen der Brennkraftmaschine der Figur 1 bei Durchführung des Verfahrens nach der Figur 2,

Figur 4

zeigt ein schematisches Zeitdiagramm von Signalen der Brennkraftmaschine der Figur 1 bei Durchführung eines dem Verfahren der Figur 2 entgegengerichteten Verfahrens,

Figur 5a

zeigt ein schematisches Ablaufdiagramm eines ersten Ausführungsbeispiels eines erfindungsgemäßen Verfahrens für das Umschalten nach den Figuren 2 bis 4, und

Figur 5b

zeigt eine schematisches Ablaufdiagramm eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Verfahrens für das Umschalten nach der Figuren 2 bis 4.

Of particular importance is the implementation of the method according to the invention in the form of a control element which is provided for a control unit of an internal combustion engine, in particular a motor vehicle. A program is stored on the control element, which is executable on a computing device, in particular on a microprocessor, and is suitable for executing the method according to the invention. In this case, the invention is thus implemented by a program stored on the control element, so that this control element provided with the program represents the invention in the same way as the method for the execution of which the program is suitable. In particular, an electrical storage medium, for example a read-only memory, can be used as the control element.

Figure 1

1 shows a schematic block diagram of an exemplary embodiment of an internal combustion engine of a motor vehicle according to the invention,

Figure 2

1 shows a schematic flow diagram of an exemplary embodiment of a method according to the invention for operating the internal combustion engine of FIG. 1,

Figure 3

1 shows a schematic time diagram of signals of the internal combustion engine of FIG. 1 when the method according to FIG. 2 is carried out,

Figure 4

1 shows a schematic time diagram of signals of the internal combustion engine of FIG. 1 when a method opposite to the method of FIG. 2 is carried out,

Figure 5a

shows a schematic flow diagram of a first embodiment of a method according to the invention for switching according to Figures 2 to 4, and

Figure 5b

shows a schematic flow diagram of a second exemplary embodiment of a method according to the invention for switching according to FIGS. 2 to 4.

1 shows an internal combustion engine 1, in which a piston 2 in a cylinder 3 back and forth is movable. The cylinder 3 has a combustion chamber 4 provided, on the valves 5, an intake pipe 6 and a Exhaust pipe 7 are connected. Furthermore are the Combustion chamber 4 can be controlled with a signal TI Injector 8 and a controllable with a signal ZW Associated with spark plug 9.

The intake pipe 6 is with an air mass sensor 10 and that Exhaust pipe 7 can be provided with a lambda sensor 11. The air mass sensor 10 measures the air mass of the Intake pipe 6 supplied fresh air and generated in Depending on this, a signal LM. The lambda sensor 11 measures the oxygen content of the exhaust gas in the exhaust pipe 7 and generates a signal λ depending on this.

A throttle valve 12 is in the intake pipe 6 housed, whose rotational position by means of a signal DK is adjustable.

In a first operating mode, the shift operation of the Internal combustion engine 1, the throttle valve 12 becomes wide open. The fuel is supplied from the injection valve 8 during one caused by the piston 2 Compression phase injected into the combustion chamber 4 locally in the immediate vicinity of the spark plug 9 and at a suitable distance before the ignition point. Then the fuel is ignited using the spark plug 9, so that the piston 2 in the now following working phase by the expansion of the ignited fuel is driven.

In a second operating mode, the homogeneous operation of the Internal combustion engine 1, the throttle valve 12 in Dependence on the desired air mass supplied partially opened or closed. The fuel will from the injector 8 during one through the piston 2 induced suction phase in the combustion chamber 4 injected. The air sucked in at the same time the injected fuel swirls and thus in the Combustion chamber 4 is distributed substantially uniformly. After that the fuel / air mixture during the Compression phase compressed to then from the spark plug 9 to be ignited. By the expansion of the inflamed The piston 2 is driven by fuel.

In shift operation as well as in homogeneous operation, the driven pistons a crankshaft 14 in a Rotational movement over which ultimately the wheels of the Motor vehicle are driven. The crankshaft 14 is assigned a speed sensor 15 which is a function of the rotational movement of the crankshaft 14 generates a signal N.

The in the shift operation and in the homogeneous operation of the Injection valve 8 injected into the combustion chamber 4 Fuel mass is in particular from a control unit 16 with a view to low fuel consumption and / or controlled low pollutant development and / or regulated. For this purpose, the control unit 16 is equipped with a Microprocessor provided in a storage medium, a program in particular in a read-only memory has saved, which is suitable for the named Control and / or regulation to perform.

The control unit 16 is acted upon by input signals, the operating variables measured by sensors Represent internal combustion engine. For example, that is Control unit 16 with the air mass sensor 10, the lambda sensor 11 and the speed sensor 15 connected. Furthermore is the control unit 16 with an accelerator pedal sensor 17 connected, which generates a signal FP, the position an accelerator pedal actuated by a driver and thus indicates the moment requested by the driver. The Control unit 16 generates output signals with which over Actuators the behavior of the internal combustion engine accordingly the desired control and / or regulation influenced can be. For example, the control unit 16 with the Injector 8, the spark plug 9 and the throttle valve 12 connected and generates the for their control required signals TI, ZW and DK.

The control unit 16 subsequently uses the Figures 2 and 3 described method for switching from carried out a shift operation in a homogeneous operation. The blocks shown in FIG. 2 represent Functions of the method, for example in the Form of software modules or the like in the Control device 16 are realized.

In FIG. 2, it is assumed in a block 21 that that the internal combustion engine 1 in a stationary Shift operation is located. Then in a block 22 for example, based on a driver's request Acceleration of the motor vehicle a transition into one Homogeneous operation requested. The time of the request of the homogeneous operation can also be seen from FIG. 3.

This is followed by debouncing using blocks 23, 24, with the a short successive switching back and forth prevented between stratified and homogeneous operation becomes. If homogeneous operation is enabled, then the transition from shift operation to homogeneous operation started by a block 25. The time when the Switching process begins, is in Figure 3 with the Reference numeral 40 marked.

At the aforementioned time 40, the throttle valve 12 by means of a block 26 from it in shift operation fully opened wdksch in at least one partially open or closed state wdkhom for controlled homogeneous operation. The rotational position of the Throttle valve 12 in homogeneous operation is on stoichiometric fuel / air mixture, i.e. to λ = 1 aligned and also depends on e.g. the requested torque and / or the speed N of the Internal combustion engine 1 and the like.

By adjusting the throttle valve 12 is the Internal combustion engine 1 from the stationary stratified operation in unsteady shift operation. In this Operating state drops the supplied to the combustion chamber 4 Air mass from a filling rlsch during the Shift work slowly towards smaller fillings. This can be seen from Figure 3. The combustion chamber 4 supplied air mass rl or its filling is from the control unit 16, inter alia, from the signal LM of the Air mass sensor 10 determined. According to a block 27 the internal combustion engine 1 continues to operate in shifts operated.

Then a block 28 of FIG non-stationary homogeneous operation switched. This is in the Figure 3 at a time 41 the case.

According to a block 29, the in the Combustion chamber 4 injected fuel mass rk in Dependence on the air mass supplied to the combustion chamber 4 rl controlled and / or regulated so that a stoichiometric fuel / air mixture occurs that so λ = 1.

The fuel mass rk influenced in this way has Consequence that - at least for a certain period of time - the torque Md output by the internal combustion engine 1 would increase. This is compensated for by the fact that Event 41, i.e. with the switchover to Homogeneous operation, the ignition angle ZW, based on the value is adjusted so that the torque Md one of which is from the requested moment resulting target torque mdsoll and thus about remains constant.

For this purpose, the fuel mass rk from the Combustion chamber 4 supplied air mass rl on the basis of a stoichiometric fuel / air mixture. Furthermore, the ignition angle ZW is dependent on the Target torque must be adjusted in the direction of a late ignition. With regard to this late adjustment, there is still one certain deviation from normal homogeneous operation before, with the temporarily too much air mass and the resulting too much generated moment of Internal combustion engine 1 is destroyed.

A block 30 checks whether the combustion chamber 4 supplied air mass rl finally to that filling which has fallen to a stationary homogeneous operation belongs to a stoichiometric fuel / air mixture. is if this is not yet the case, it will loop over waiting for block 29 further. However, if this is the case, so the internal combustion engine 1 in the stationary Homogeneous operation without an ignition angle adjustment using the Blocks 31 continued to operate. In Figure 3, this is in one the point in time marked with the reference number 42 Case.

This corresponds to that in this stationary homogeneous operation Combustion chamber 4 supplied air mass of the filling rlhom for the Homogeneous operation and the ignition angle zwhom for the spark plug 9 also corresponds to that for homogeneous operation. The same applies to the rotary position wdkhom Throttle valve 12.

In Figure 3, the stationary shift operation is as Area A, the unsteady shift operation as area B, the unsteady homogeneous operation as area C and the stationary homogeneous operation marked as area D.

FIG. 4 shows a switchover from homogeneous operation represented in a shift operation. It is from one stationary homogeneous operation in which for example, due to the size of the company Internal combustion engine 1 in a stationary shift operation should be transferred.

The switch to shift operation is carried out by the Control unit 16 initiated by the requirement of Homogeneous operation is withdrawn. After a debouncing the switch to shift operation is released and it turns the throttle valve 12 into that rotational position controlled, which is intended for shift operation. there it is a rotary position in which the Throttle valve 12 is largely open. This is through the transition from wdkhom to wdksch in FIG. 4 shown.

It is possible that this transition with or without Consideration of a throttle overshoot from the control unit 16 is processed further. This is in the Figure 4 by solid or dashed lines shown.

The opening of the throttle valve 12 has the consequence that the Combustion chamber 4 supplied air mass rl increases. This goes in 4 from the course of rlhom. After that the switching from the described transient occurs Homogeneous operation in a transient shift operation. This is the case in FIG. 4 at time 43.

Before switching to shift operation, the increasing air mass supplied to the combustion chamber 4 compensates that the injected fuel mass rk increased and the ignition angle ZW is retarded. This results from the course of rkhom and zwhom.

After switching to shift operation, the injected fuel mass rk to the value rksch for the Shift operation set. The same applies to the Ignition angle ZW, which is between the values for the Shift operation is set.

4 shows the stationary homogeneous operation as Area A, the transient homogeneous operation as area B, the transient shift operation as area C and the stationary shift operation marked as area D.

FIG. 5a shows a first method that during the changeover from shift operation to Homogeneous operation according to Figures 2 and 3 or vice versa 4 can be used. The procedure serves to, torque changes of the internal combustion engine 1, that is Changes in the delivered actual torque Md during the Switching process to recognize. The shown in Figure 5a Blocks represent functions of the method that for example in the form of software modules or The like are realized in the control unit 16.

In area A of FIGS. 3 and 4, the Control unit 16 in a block 50 a first Speed gradient dN (1) from that in two successive The speed N of the internal combustion engine 1 recorded at times calculated.

Then in the following areas B, C and D the Figures 3 and 4 of the control unit 16 at least in each case once, possibly also several times in a block 51 an expected speed N 'depending on the first Speed gradient dN (1) or further speed gradients dN (i) and the target torque mdsoll calculated, the target torque Among other things, mdsoll depends on that Moment that the driver on the accelerator pedal 17 from the Internal combustion engine 1 requests. This expected speed N ' is in a block 52 with the detected speed N of Internal combustion engine 1 compared.

If the difference is smaller than an allowed one Speed difference _N, is the amount of N'-N <_N, see above this results in a slight change in torque Internal combustion engine 1 closed. this means at the same time that the internal combustion engine 1 no bucking or the like during the switching process. It no further action is taken.

If the difference is greater than the permitted speed difference _N, if the amount of N'-N> _N, then it becomes closed a torque change that caused a bucking of the Comprises internal combustion engine 1 or represents. In In this case, the permissible limit is exceeded Speed difference _N due to uneven running or jerking closed during the switching process.

Thereafter, in a block 53, the two become temporal last detected speeds N of the internal combustion engine 1 further speed gradient dN (i) calculated with the last calculated speed gradient dN (i-1) compared becomes. This results in an approximately constant course of the Speed gradient, it is concluded that the detected torque change on a load change is based, i.e. is a consequence of an incline, and that there is no jerking and no uneven running. Therefore no further measures are taken.

However, there is an inconsistent course of the calculated Speed gradient, this is used as a confirmation of Unrest and the like during the switching process scored. This has 54 countermeasures in a block Result that counteract the jerking or the uneven running should, and which will be explained.

FIG. 5b shows a second method which during the changeover from shift operation to Homogeneous operation according to Figures 2 and 3 or vice versa 4 can be used. The procedure serves to, torque changes of the internal combustion engine 1, that is Changes in the actual torque Md during the switching process to recognize. Make the blocks shown in Figure 5b functions of the method, which are described, for example, in the form of software modules or the like in the Control device 16 are realized.

In each of the areas A, B, C and D of FIGS. 3 and 4 are blocks 55, 56 at least two speeds N of Engine 1 at successive times recorded, from which then a speed gradient dN (i) from the Control unit 16 is calculated. Two at a time calculated speed gradients dN (i) and dN (i + 1) are in a block 57 compared with each other. It results an approximately steady course of the speed gradient, so concluded that no or only changes in load based torque changes are present, one Follow, for example, a change in driving resistance and that there is no jerking and no uneven running available. There are therefore no further measures taken.

However, there is an inconsistent course of the calculated Speed gradient, so it is a judder or on Unrest and the like during the switching process closed. This has 58 countermeasures in a block Result that counteract the jerking or the uneven running should, and which will be explained.

Are according to one of the methods of Figures 5a or 5b Changes in the actual torque Md of the internal combustion engine 1 have been recognized during the switching process, so in countermeasures initiated in blocks 54 and 58 respectively. at These countermeasures are changes in the Operating variables of the internal combustion engine 1, with which the actual moment Md of the internal combustion engine 1 is influenced.

When switching from shift operation to Homogeneous operation according to Figures 2 and 3 are in area A no changes in the operating parameters of the internal combustion engine 1 made.

When torque changes are detected in area B. the fuel mass rk to be injected into the combustion chamber 4 reduced or increased in such a way that the observed Torque changes are less. In area C determined changes in torque is the ignition angle ZW or the ignition timing is adjusted so late that the excessive filling rl of the combustion chamber 4 compensates and so that the torque changes are reduced. at detected torque changes in areas B and C are dynamic torque changes that by adaptive changes to the above Farm sizes can be permanently corrected.

With torque changes detected in area D. are static torque changes that through a corresponding adaptive influencing of the Shift operation to be injected into the combustion chamber 4 Fuel mass rk or by influencing the im Homogeneous operation air mass rl and des Fuel rk can be compensated.

When switching from homogeneous to Shift operation according to FIG. 4 does not occur in area A. Changes in the operating variables of the internal combustion engine 1 performed.

When torque changes are detected in area B. the ignition angle ZW or the ignition timing is late adjusted so that the excessive filling rl of the combustion chamber 4th compensated and thus the torque changes reduced become. When detected in area C. Torque changes are in the combustion chamber 4th Fuel mass rk to be injected is reduced or so increases the detected torque changes decrease. If torque changes are found in areas B and C are dynamic Torque changes caused by adaptive changes in the the respective sizes of operations are permanently corrected can.

With torque changes detected in area D. are static torque changes that through a corresponding adaptive influence e.g. the in Shift operation to be injected into the combustion chamber 4 Fuel mass rk can be compensated.

The above-mentioned influencing of company variables of Internal combustion engine 1 for compensation of uneven running or jerking during a switching process can be made immediately, so that, if necessary, another Effect occurs during the current switching process. It but it is also possible that the influences derarut be carried out that an effect only with the next Switching process is present.

Claims (13)

1. Method for operating an internal combustion engine (1), in particular of a motor vehicle, in which fuel is injected directly into a combustion chamber (4) either in a first operating mode during a compression phase or in a second operating mode during an induction phase, in which the engine is switched between the two operating modes and in which the operating variables which influence the actual moment (Md) of the internal combustion engine (1) are controlled differently in the two operating modes as a function of a desired moment (mdsoll), characterized in that a change in the actual moment (Md) while the engine is being switched between operating modes is determined (Fig. 5a, Fig. 5b), and in that at least one of the operating variables is influenced (54, 58) as a function of this change.
2. Method according to Claim 1, characterized in that the change in the actual moment (Md) is determined (50, 51, 52, 53, 55, 56, 57) as a function of the recorded rotational speed (N) of the internal combustion engine.
3. Method according to one of Claims 1 and 2, characterized in that an expected rotational speed (N') is determined (51) as a function of the desired moment (mdsoll), and in that the expected rotational speed (N') is compared (52) with the recorded rotational speed (N) of the internal combustion engine (1).
4. Method according to Claim 3, characterized in that at least one of the operating variables of the internal combustion engine (1) is influenced if the recorded rotational speed (N) deviates from the expected rotational speed (N') by more than a predeterminable rotational speed difference (λN).
5. Method according to Claim 4, characterized in that no influencing measure is carried out if a plurality of successive rotational-speed differences (dN(i-1), dN(i)) have an approximately constant curve (53).
6. Method according to one of Claims 1 to 2, characterized in that at least two rotational speed gradients (dN(i), dN(i+1)) are determined (55, 56) from the recorded rotational speed (N) of the internal combustion engine (1), and in that two of the rotational-speed gradients (dN(i-1), dN(i)) are compared (57) with one another.
7. Method according to Claim 6, characterized in that at least one of the operating variables of the internal combustion engine (1) is influenced (58) if the two rotational-speed gradients (dN(i-1), dN(i)) have a curve which is not constant.
8. Method according to one of the preceding claims, characterized in that the influencing of one of the operating variables is carried out adaptively.
9. Method according to one of the preceding claims, characterized in that the influencing of one of the operating variables is only carried out for the next operation of switching over the engine.
10. Method according to one of the preceding claims, characterized in that in the first operating mode the mass of fuel (rk) which is injected is influenced in particular in the sense of an increase.
11. Method according to one of the preceding claims, characterized in that in the second operating mode the ignition angle (ZW) or the ignition time is influenced in particular in the sense of a shift towards a later point.
12. Control element, in particular read only memory, for a control unit (16) of an internal combustion engine (1), in particular of a motor vehicle, which stores a program which can run on a computer unit, in particular on a microprocessor, and is suitable for carrying out a method according to one of Claims 1 to 11.
13. Internal combustion engine (1) in particular for a motor vehicle, having an injection valve (8), by which fuel can be injected directly into a combustion chamber (4) either, in a first operating mode, during a compression phase or, in a second operating mode, during an induction phase, and having a control unit (16) for switching between the two operating modes and for differently controlling the operating variables which influence the actual moment (Md) of the internal combustion engine (1) in the two operating modes as a function of a desired moment (mdsoll), characterized in that a change in the actual moment (Md) during an operation of switching between the two operating modes can be determined by the control unit (16) (Fig. 5a, Fig. 5b), and in that at least one of the operating variables can be influenced (54, 58) by the control unit (16) as a function of this change.

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