DE102008043165A1 - Method for calibrating amount of partial fuel injection into fuel injection system of internal combustion engine of motor vehicle, involves determining correction value for fuel injection by stimulating pattern and by changing vibration - Google Patents

Abstract

The method involves determining a correction value for partial fuel injection in a cylinder of an internal combustion engine by stimulating an injection pattern and by changing drive vibration in the internal combustion engine. The drive vibration is caused by the injection pattern. Amplitude of the drive vibration is minimized or adjusted to minimum. The drive vibration is changed based on the amplitude or a phase position of the drive vibration. The effect of the drive vibration is determined by amount and/or phase of speed information. An independent claim is also included for a device for calibrating injection amount of partial fuel injection into a fuel injection system of an internal combustion engine of a motor vehicle.

Description

State of the art

The The invention relates to a method for calibrating the injection quantity a partial injection in an injection system of an internal combustion engine in particular a motor vehicle and a corresponding device according to the Topics of the respective independent claims.

In modern fuel injection systems in particular self-igniting Internal combustion engines are injected by injectors into combustion chambers Fuel quantities divided into several partial injections, which are arranged close to one another and, for example, from one or more ago a main injection applied pre-injection (s) exist. The time interval between two partial injections is thereby by the pause time between two consecutive times electrical drive pulses of the injectors, through a crankshaft angle or by a combination of these two sizes Are defined.

These Partial injections result in improved mixture preparation and thus lower exhaust emissions of the internal combustion engine, a reduced noise during combustion as well an increased mechanical power output of the internal combustion engine. For simultaneous optimization of noise and exhaust gas is the injection quantity of the pilot injection chosen very small, partially near the smallest by one Injector representable amount of fuel.

In order to be able to ensure exact compliance with the pre-injection quantity during a drift of the injector behavior over the running time of the injector, functions are necessary which make it possible to calibrate the pilot injection quantities during operation of the internal combustion engine. So goes out of the DE 103 43 759 a method in which in idling operation of an internal combustion engine, a pilot injection is switched off at one or more cylinders and is closed from the control quantities of an idle controller and a flow compensator on the basis of cylinder-specific corrections to the pilot injection.

Disclosure of the invention

Of the The present invention is based on the idea at a here affected calibration method a correction value for the partial injection into a single cylinder by stimulation an injection pattern and by changing or compensating a speed vibration caused by the injection pattern the internal combustion engine (BKM) to determine.

In In a preferred embodiment, a control algorithm is provided, each for a cylinder with half, third, fourth, fifth, etc., camshaft frequency, an anticipated pilot injection quantity between pre-injection and main injection "rearranged". Ie. It is proposed to use a cylinder alternately with one Single injection and a multiple injection, preferably one composed of a pilot injection VE and a main injection HE Double injection, to apply and a correction value for the pilot injection or partial injection by change or compensation of a speed vibration caused by the injection pattern to determine the BKM.

The Activation duration of a partial injection, preferably a pre-injection, is preferably varied in the said method until the effect on certain, preferably empirically predeterminable frequencies a speed signal is minimized or regulated to zero.

It It should be emphasized that the mentioned speed oscillation is not only by means of a speed signal but also by others the skilled person common input quantities can, such as a lambda signal, a knock signal, an ion current signal or the like.

at The invention is based in particular on the knowledge that in Trap of a not yet or only partially calibrated Pre-injection quantity vibrations with half, three half, etc. camshaft frequency occur the speed signal, which preferably by means of a control can be adjusted to a minimum value.

The called minimization of the speed oscillations is preferred either on the basis of the amplitude and / or the phase position of said Speed oscillation, or by a combination of these two Sizes, and is preferred by magnitude and phase a speed information transformed into the frequency domain determined.

In a preferred embodiment, two work phases are formed, namely a learning phase and a subsequent application phase. In the learning phase, a correction value of a cylinder is initially determined by said stimulation of an injection pattern and by compensating the speed oscillation caused by the injection pattern. On the basis of the correction value determined in this way, in the subsequent application phase the determined correction value is preferably in normal operation of the internal combustion engine to a currently present control variable of the pilot injection turned on.

The inventive method allows in the fired operation of an internal combustion engine or in the current Driving an underlying motor vehicle a precise Calibration of the pilot injection quantity, not necessarily idling or stationary operation of the internal combustion engine.

There a cylinder compensation function in the proposed method is not necessary, the procedure may apply to engines with unequal ignition distance and be used advantageously in single-cylinder engines.

Across from The method described in the introduction requires the invention Do not use push-pull operation or even stationary idle operation the internal combustion engine. It should be emphasized that it is in the in the prior art known methods during a calibration in Idle mode not to a change of the load torque is allowed, because it falsifies the calibration result becomes. Therefore, the known calibration can only performed in workshop operation with the necessary precision become. Also, for the correction to be achieved, the pilot injection quantity no quantity compensation scheme needed anymore. The calibration according to the known method is acoustically especially at idle noticeable and therefore leads to loss of comfort during operation of the internal combustion engine.

additionally The said overrun operation can not be used in all applications of diesel engines be applied, for. B. occurs in the off-road area, in stationary engines or in automatic transmissions rarely or rarely thrust operation on. In addition, the aforementioned compensation schemes are after Current state of the art only for engines with the same firing intervals possible, especially not with single-cylinder engines.

drawing

The Invention will be described below with reference to preferred embodiments and explained in more detail with reference to the drawing, from which further features, features and advantages of the invention emerge.

in the Show individual

1 a schematic representation of a fuel metering system of an internal combustion engine according to the prior art, in which the present invention can be used;

2 a detailed representation of the known calculation of driving durations in the 1 shown electrically operated valve;

3 a typical injection course with a pre-injection and main injection, based on which the rearrangement of the injection quantity according to the invention between pre- and main injection is illustrated;

4 a preferred embodiment of a correction function according to the invention based on a block diagram; and

5 a measured on a real Kraftstoffzumesssystem in the learning phase according to the invention transmission behavior.

Description of exemplary embodiments

The 1 shows a block diagram of the essential elements of a fuel metering system of an internal combustion engine. The internal combustion engine 10 obtained from a fuel metering unit 30 a certain amount of fuel at a given time metered. Various sensors 40 capture readings 15 , which characterize the operating state of the internal combustion engine, and forward them to a control unit 20 , The control unit 20 also different output signals 25 additional sensors 45 fed. The recorded measured values 15 characterize the state of the fuel metering unit such as the driver's request. The control unit 20 calculated from these measurements 15 and the other sizes 25 drive pulses 35 with which the fuel metering unit 30 is charged.

The internal combustion engine is preferably a direct-injection and / or a self-igniting internal combustion engine. The fuel metering unit 30 can be configured differently. For example, as a fuel metering unit, a distributor pump can be used in which a solenoid valve determines the time and / or the duration of the fuel injection.

Of Further, the fuel metering unit as a common rail system be educated. Known in this condensed a high pressure fuel pump in a store. From this store then the fuel passes through injectors into the combustion chambers the internal combustion engine. The duration and / or the beginning of the fuel injection is controlled by the injectors. This includes the injectors preferably a solenoid valve or a piezoelectric actuator.

The control unit 20 calculates in known manner the fuel quantity to be injected into the internal combustion engine. This calculation he follows depending on different readings 15 , such as the speed n, the engine temperature, the actual start of injection and possibly other variables 25 that characterize the operating condition of the vehicle. These other variables include the position of the accelerator pedal or the pressure and the temperature of the ambient air. The control unit 20 then converts the desired amount of fuel into corresponding drive pulses of the injectors.

at The said engines are often one or several small amounts of fuel just before the actual main injection into metered the cylinder. This can be the noise behavior the engine are significantly improved. This injection will as pre-injection and the actual injection as the main injection designated. Furthermore, it can be provided that one or more small amount of fuel (s) after the main injection become. This is then called post-injection. Further can be provided that the individual injections in more Partial injections are split.

Problematic In such fuel metering systems, the electrically operated ones Valves with the same control signal different amounts of fuel can eat. In particular, the driving time at which Just fuel is metered depends on different Factors off. This Mindestansteuerdauer leads to a Injection, whereas Ansteuerverdauern smaller than the Mindestansteuerdauer do not lead to an injection. This minimum tax period depends on various factors, such as the Temperature, fuel grade, life, rail pressure, manufacturing tolerances injectors and other influences. To get an accurate To be able to achieve fuel metering, this minimum activation period must be ensured be known.

A device for controlling the fuel metering in an internal combustion engine is in the 2 shown. Already in 1 Elements described are designated by corresponding reference numerals. Signals from the sensors 45 as well as other sensors, which are not shown, reach a quantity specification 110 , This quantity specification 110 calculates a fuel quantity QKW that corresponds to the driver's request. This quantity signal QKW reaches a connection point 115 , at the second input of which the output signal QKM of a second synchronization 155 is applied. The output signal of the first node 115 arrives at a second node 130 which in turn is a driving duration calculation 140 applied. At the second input of the second node 130 the signal QKO is a zero-quantity correction 142 at.

In the two connection points 115 and 130 the quantity signals are preferably linked additively. The drive duration calculation 140 calculated from the output of the node 130 the drive signal for Beauf suppression of a fuel metering unit 30 , The actuation duration calculation calculates the actuation duration with which the electrically actuated valves are acted upon.

On a donor wheel 120 Different markers are arranged by a sensor 125 be scanned. In the illustrated embodiment, the sender wheel is a so-called segment wheel, which has a number of markings corresponding to the number of cylinders, in the exemplary embodiment illustrated this is four. This donor wheel is preferably arranged on a crankshaft of the internal combustion engine, not shown. This means that per motor revolution, a number is generated at the pulses, which corresponds to twice the number of cylinders. The sensor 125 supplies a corresponding number of pulses to a first synchronization 150 ,

The first synchronization 150 applies a first regulator 171 , a second regulator 172 , a third controller 173 and a fourth controller 174 , The number of controllers corresponds to the number of cylinders. The output signals of the four controllers then go to the said second synchronization 155 ,

Such a device, without zero-offset 142 is equipped in the DE 195 27 218 shown in more detail. This facility works as follows. Based on various signals, such as a signal that identifies the driver's request, determines the quantity specification 110 the fuel quantity request signal QKW, which is required to provide the driver's desired moment. In addition to the driver request signal also other signals can be processed. In particular, the speed signal and various temperature and pressure values are processed in addition to the driver request signal. Furthermore, there is the possibility that signals from other control units are transmitted to the quantity specification requesting a torque request and / or a quantity request. Such another control device may, for. B. be a transmission control, which influences the torque from the engine during the switching process.

Due to tolerances, in particular the fuel metering unit 30 Deviations occur between the desired injection quantity and the actually injected fuel quantity. The individual cylinders measure the internal combustion engine usually with the same control signal to different amounts of fuel.

These variations between the individual cylinders are usually compensated with a quantity compensation control (MAR). Such a quantity compensation control is schematically in the upper part of 2 shown. For quantity balance control each cylinder of the internal combustion engine is assigned a controller. So the first cylinder is the first regulator 171 , the second cylinder the second regulator 172 , the third cylinder is the third regulator 173 and the fourth cylinder, the fourth controller 174 assigned. It can also be provided that only one controller is provided, which is assigned alternately to the individual cylinders. By means of the sensor 125 and the donor wheel 120 determines the first synchronization 150 a setpoint and an actual value for each individual controller. It is provided that to compensate for tolerances of the encoder wheel and to compensate for torsional vibrations a special filtering of the signal of the sensor 125 he follows. The output signals of the controller 171 to 174 become a second synchronization 155 supplied, which provides a correction amount QKM, with the quantity request QKW is corrected.

These Quantity compensation control is designed so that the controller, the the amount of the individual cylinders to a common Regulate the mean. Measures a cylinder due to tolerances one increased amount of fuel, so will for this Cylinder a negative fuel quantity QKM to the driver's request QKW added. Measures a cylinder too little amount of fuel to, a positive fuel quantity QKM becomes the driver's desired quantity Added QKW. With such quantity errors, rotational nonuniformity occurs on. This has the effect that vibrations are superimposed on the speed signal are their frequency of the camshaft frequency and / or multiples correspond to the camshaft frequency. These proportions in the speed signal with camshaft frequency characterize the rotational nonuniformity and are adjusted to zero by the volume compensation scheme.

Quantity average error can not be corrected with this quantity compensation scheme become. In particular, errors that are based on that No fuel is added below the minimum driving time is not corrected with such a volume compensation scheme become.

In the 3 is now a typical injection pattern, consisting of a pilot injection and a main injection, shown schematically. The upper diagram shows the activation of an injector, whereby the current regulation is neglected. The lower diagram shows the time-delayed fuel flow resulting from the mentioned activation through the injector nozzle. The areas under the respective curves of the fuel flow thereby correspond to the injected fuel quantity.

• – „Lernmodus”: Ermitteln des Korrekturwerts durch Stimulation des Einspritzmusters und Ausregeln der Drehzahlschwingung
• – „Anwendungsmodus”: Aufsteuern des ermittelten Korrekturwerts im normalen Motorbetrieb

The calibration method according to the invention now has the already mentioned two operating phases or operating modes:

• "Learning mode": determining the correction value by stimulating the injection pattern and regulating the speed oscillation
• - "Application mode": Activation of the determined correction value during normal engine operation

in the "Learn" mode supports the invention Method in each case for a cylinder and with, for example, half Camshaft frequency, the pilot injection amount between the pilot injection and the main injection preferably cyclically recurring order. One such rearrangement cycle is preferably repeated more than once, but in the simplest case, it can only be done by a single cycle, d. H. a single rearrangement, be realized because already a single cycle to cause a named speed oscillation can.

It It should be emphasized that the injection pattern described herein the rearrangement of a pilot injection with respect to a main injection only is exemplary and in principle also other injection pattern are conceivable, by means of which a named speed oscillation can be stimulated. So, instead of a pre-injection, a post-injection will be relocated accordingly or another more complex "redistribution pattern" in which more is re-stored as a partial injection.

In the in the 3 In the embodiment shown, the fuel quantity provided for the pilot injection is used 300 alternately as fuel quantity 305 to the main injection 310 turned on. It is understood, however, that other forms of rearrangement are possible, such as. The rearrangement of the amount of fuel a pilot injection with a time-separated from the main injection post-injection.

The present invention is based on the finding that only in cases in which the amounts of fuel physically removed during the cyclic rearrangement 300 . 305 are the same, no speed oscillation occurs. But as already on the basis of 1 has been described, it may happen that the electrically operated valves of the injectors with the same drive signal to measure different amounts of fuel. Therefore, is not automatically ge with matching drive time ge Ensures that the two fuel quantities 300 and 305 to match. Even with drifted injectors or non-taught calibration procedures are the Kraftoffmengen 300 . 305 naturally unequal and it occur on the speed oscillations described above. The control objective of the calibration procedure is therefore to control these speed oscillations to a minimum or to detect the phase jump. The manipulated variable for this is a correction intervention on the activation duration of the pre-injection 300 ,

It is understood that the inventive concept not only applicable to calibration pilot injections, but also on the calibration of partial injections, which performed in addition to a main injection be, for example, on post-injection or the like.

On the basis of in the 4 shown block diagram of a preferred device according to the invention preferred intervention of the calibration method according to the invention in the engine control will be described in more detail.

Starting from a moment path 400 a desired torque m is predetermined, which represents a desired value of the internal torque at the engine from the coordination of driver specification, speed controller, etc. This target torque m is first by means of a torque quantity conversion 405 into a setpoint value of the pilot injection quantity qVEsoll as well as a main injection quantity qHEsoll.

In a logical or processually subsequently arranged amount-drive duration implementation 410 are at the input of the setpoint amounts of the pre-injection with imprinted stimulation in half camshaft frequency qVEstim and a corresponding value qHEstim for the main injection before, which of a correction function ZFX described below 430 to be provided.

The mentioned quantity-drive duration implementation 410 calculates from the values qVEstim and qHEstim values of the activation duration for the pilot injection tiVE and the main injection tiHE, without the correction / calibration function according to the invention. At the injectors shown only schematically 415 is then in each case a value tiVEcorr for the control period of the pilot injection including a corresponding control action of a calibration function and a Ansteuerdauerwert for the main injection. By means of injectors 415 these control values are converted into actual values qVEphys for the injected pilot injection quantity and qHEphys for the main injection quantity to be injected. Based on these actual values, the motor, which is also indicated only schematically, generates 420 in operation in a conventional manner a rotational movement of its (not shown) crankshaft with a certain speed n.

By means of a spectral analysis 425 the amplitude and / or the phase of the resulting speed oscillation at half the camshaft frequency, and alternatively at other frequencies than the fundamental frequency of the vibration evaluated. The sequence control of the subsequent correction function ZFX 430 calculates a logic signal stVEstim for stimulation of the injection pattern at half camshaft frequency and from the phase and / or the amplitude of a control intervention tiVEtrim the correction function ZFX, ie a corresponding control action to compensate for the assumed injector drift.

The Indian 4 The process shown additionally contains logical links in the form of a first node 435 and a second node 440 and a first switch 445 and a second switch 450 , It should be noted that in the present embodiment, the first switch 445 rather works in the form of a switch and either the lower path 455 switches to continuity or the upper path 460 ,

By means of the first node 435 can the aforementioned setpoint value of the pilot injection qVEsoll aufsteuern to said setpoint of the main injection quantity qHEsoll. Whether this control takes place or not, depends on the switch position of the first switch 445 from. By means of the second switch 450 on the other hand, it is controlled whether the setpoint value of the pilot injection quantity VEsoll is further processed in the form of a separate pilot injection, ie the pilot injection quantity is then not raised to the setpoint value of the main injection quantity qHEsoll. In the embodiment shown, the two switches operate 445 . 450 thus in opposite directions, ie when the first switch 445 opens, the second switch closes 450 , and vice versa.

The Switch positions of the two switches are from the correction function ZFX driven by the said logic signal stVEstim, wherein in one cycle (i.e., at half camshaft frequency) - like described above - the pilot injection from the main injection separated, d. H. the pilot injection quantity does not affect the main injection quantity is added, and wherein in the subsequent cycle the pilot injection represented in the form of a prolonged main injection is, d. H. the pilot injection quantity is added to the main injection quantity.

At the second connection point, the named control intervention tiVEtrim and the present the value of the activation duration for the pre-injection tiVE is added up in order to supply the corrected value tiVEcorr for the activation period of the pre-injection as a result to the respective injector / injectors.

In the 5a - 5c is the transfer behavior in mode "learning" from tiVEtrim to amplitude ( 5a ) and phase ( 5b ) of the half-camshaft frequency vibration vibration by a measurement. In particular, these figures illustrate the behavior of amplitude and phase of 0.5 * f _NW when the drive duration trim on the pilot injection changes. In the value of the control engagement, which results in an amplitude = 0 or a minimum amplitude, those in the 3 shown fuel quantities 300 and 305 equal. Off the minimum, the amplitude increases again. The phase information of the vibration is used to distinguish whether an excessive or too small amount is injected at the cylinder, ie for the identification of the control sense.

The control intervention tiVEtrim with zero speed oscillation (ie amplitude = 0) represents the correction value at which the equation qVEsoll = qVEphys is satisfied.

This correction value tiVEtrim ( 5c ), possibly depending on other engine parameters such as the rail pressure, stored. In the "Apply" work phase, the correction value matching the engine operating state is reopened. Optionally, the correction value used can also be determined from a plurality of learning values of adjacent operating points.

alternative to the described control can also the oscillation amplitude the speed n at half the camshaft frequency as a measure of the pilot injection quantity can be used. To be in this solution robust against changes in the track behavior Being able to be, by means of a quantity variation of the skin injection be preceded by a route identification. Alternative to other than ½ can also be used Divider of the camshaft frequency to be excited: z. B. 1/3 camshaft frequency by variation two camshaft revolutions with pre-injection and one camshaft revolution without pilot injection, ¼ camshaft frequency etc. For the evaluation of the speed oscillation are here also the selected excitation frequency and / or their Multiples used. Alternatively to the described evaluation of Speed oscillation at half the camshaft frequency can additionally or alternatively even integer multiples of Excitation frequency used to determine amplitude and phase become. A route identification as mentioned above can also be used for controlled systems with oscillatory Components the phase for the later calibration procedure to learn. Alternatively to that described in the disclosure of the invention Correction intervention on the control period of the pilot injection can Also, a correction to the desired amount of the pilot injection done.

in the Difference to the known methods is during the Calibration not staying the pre-injection stopped or switched off but alternately stimulated on a cylinder. In a work cycle of the cylinder to be calibrated becomes the normal injection pattern discontinued from pre-injection and main injection. In the following work cycle the pilot injection is switched off and the pre-injection quantity slammed the main injection. This will, if an error the pre-injection amount is present, a speed oscillation with half Camshaft frequency (and harmonics) excited. The resulting Speed oscillation is analyzed and by interfering with the activation time of the injector regulated. The corrective action is a measure of the Calibration value of the injector.

Other resulting advantages over the known methods are the robustness to changes in the average load torque, since in the preferred embodiment described only an analysis takes place at half the camshaft frequency and a correlation between a change in quantity in the main injection and the pilot injection is made. This is possible on the assumption that the change of the injector slope δm / δ drive duration for the main injection over the lifetime is small. This results in a robustness to different drive trains, since the calibration can be carried out in a closed loop. Due to the robust, control-based calibration method, the effort for the application of the function is less than in the previously known speed-based methods. Due to the fact that it is largely independent of the drivetrain, it is not possible to expect different settings for variants of powertrain configurations. Furthermore, there is no influence of cylinder-specific disturbances or pitch errors of the tachometer wheel, since these can not occur at half the camshaft frequency. In addition, the calibration is also possible in an operating range in which the driver is insensitive to changes in the combustion noise. Finally, a calibration in wide speed and load ranges with the rail pressures specified for these operating points, or in a limited interval to the predetermined rail pressure, performed. In this case, no special rail pressures must be set for calibration, the for this operation point would not be optimal and lead to the mentioned noise.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10343759 [0004]
• - DE 19527218 [0033]

Claims (14)

Method for calibrating the injection quantity of at least one in addition to a main injection ( 310 ) provided partial injection ( 300 ) in an injection system ( 30 ) an internal combustion engine ( 10 ) in particular of a motor vehicle, characterized in that a correction value ( 415 ) for a partial injection ( 300 ) in a single cylinder of the internal combustion engine by stimulation of an injection pattern and by changing a speed oscillation caused by the injection pattern in the internal combustion engine ( 10 ) is determined. Method according to claim 1, characterized in that that the amplitude of the speed oscillation minimizes or on Minimum is regulated. Method according to claim 1, characterized in that that a change in the phase of the speed oscillation, in particular a phase jump is used as a basis. Method according to one of the preceding claims, characterized in that the drive time at least one Partial injection is varied until the effect on certain, preferably empirically predeterminable frequencies of a speed signal minimized or zeroed out. Method according to one of the preceding claims, characterized in that for the individual cylinder with a fraction of the camshaft frequency, preferably with a camshaft frequency (1 / n), where n = 2, 3, 4, ..., a predetermined injection quantity of a partial injection ( 300 ) between a pre-injection or a post-injection and a main injection ( 310 ) is relocated. Method according to one of the preceding claims, characterized in that the said change in the speed oscillation takes place on the basis of the amplitude or the phase position of the speed oscillation or on the basis of a combination of these two variables ( 420 . 425 ). Method according to one of the preceding claims, characterized in that the calibration in at least two Work phases, with a correction value in the first phase of work a cylinder by said stimulation of an injection pattern and by said changing the through the injection pattern caused speed oscillation is determined and wherein the so determined correction value in the operation of the internal combustion engine to a currently present control variable of the pilot injection is turned on. Method according to one of the preceding claims, characterized in that an effect on the speed vibration by amount and / or phase of a transformed into the frequency domain Speed information is determined. Method according to one of the preceding claims, characterized in that the amplitude and / or the phase of the speed oscillation by means of spectral analysis ( 425 ) is evaluated, wherein at least the fundamental frequency of the speed oscillation is taken into account. Method according to claim 9, characterized in that in spectral analysis ( 425 ) at least one frequency other than the fundamental frequency of the speed oscillation is evaluated. Method according to one of the preceding claims, characterized in that from the amplitude of the speed oscillation, a logic signal for stimulating the injection pattern and from the phase of the speed oscillation, a control intervention is generated ( 430 ). Device for calibrating the injection quantity in addition to a main injection ( 310 ) provided partial injection ( 300 ) in an injection system ( 30 ) an internal combustion engine ( 10 ) in particular of a motor vehicle, characterized by computing means or control means ( 430 ) for determining a correction value for a partial injection ( 300 ) in a single cylinder of the internal combustion engine ( 10 ) based on stimulation of an injection pattern and changing a speed vibration in the internal combustion engine caused by the injection pattern. Apparatus according to claim 12, characterized by a controller for regulating the speed oscillation to a minimum. Device according to claim 12 or 13, characterized by a logic unit ( 430 ) for calculating a logic signal for stimulating the injection pattern from the amplitude of the speed oscillation and for generating a control input from the phase of the speed oscillation.