EP2809928A1

EP2809928A1 - Method for controlling an internal combustion engine

Info

Publication number: EP2809928A1
Application number: EP13700554.2A
Authority: EP
Inventors: Michael Walter; Bjoern Bischoff; Udo Schulz; Brahim Baqasse; Markus Hernier; Thibaut BEYRATH; Stefan Bollinger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2012-02-03
Filing date: 2013-01-14
Publication date: 2014-12-10
Also published as: US20150053179A1; JP2015505591A; KR20140119086A; DE102012201601A1; JP5933760B2; WO2013113542A1

Abstract

The invention relates to a method for controlling an internal combustion engine (10) involving the following steps: - using the pressure sensor method, a first actuation period (t_vorl) for a first injector (20d) is determined in a first step (40), in which period a desired quantity of fuel is injected into a first cylinder (12d). The first actuation period (t_vorl) is stored in a control and/or regulating device (38) in a non-volatile manner; - in a second step (42), the first injector (20d) is actuated with the first actuation period (t_vorl), and a quantity replacement signal resulting therefrom is saved depending on the drive train parameters in a learning characteristic map and is stored in the control and/or regulating device (38) in a non-volatile manner; - in a third step (44), an actuation period of the injectors (12) which are assigned to the cylinders (20) is varied for all further cylinders (20) by means of zero quantity calibration, until the quantity replacement signal which was determined in the second step (42) is reached as a desired value, the actuation period thus determined being stored in the control and/or regulating device (38) in a non-volatile manner.

Description

description

title

Method for controlling an internal combustion engine Prior art

The invention relates to a method for controlling an internal combustion engine.

In modern fuel injection systems of the type concerned here, for example in common-rail diesel injection systems, to improve the

Mixture preparation time before or after the actual

Main injections lying partial injections with relatively small

Fuel quantities realized. The total injection amount, usually calculated on the basis of a driver's torque demand, becomes thereby

for example, divided into two pilot injections and a main injection.

The injection quantities of the pilot injections should be as small as possible in order to avoid emission disadvantages. On the other hand, the pilot injection quantities must be large enough so that the minimum amount of fuel necessary for the combustion process is always injected even taking into account all tolerance sources. The main source of tolerance is age-related

Drift of the injectors.

From DE 199 45 618 A1 a method is known with which the drift of an injector is adapted via a so-called zero-quantity calibration and

is compensated. In this case, in a coasting operation of the internal combustion engine, a control period and thus the injected Kraftstoffm narrow each injector varies until a change of a so-called

Quantity replacement signal occurs. Since the injected Kraftstoffm tight can not be measured directly, one manages with a quantity replacement signal that correlates with the injected fuel quantity. The quantity replacement signal is, for example, a speed change of

Crankshaft, an output of a lambda probe or an output of an ion current probe. The activation duration of the injector at which a change in the quantity replacement signal occurs is stored as minimum activation duration and used to compensate for the drift of the injector.

DE 10 2008 002 482 A1 describes a method which evaluates a relationship between the values of the minimum control duration and the respective injection quantity resulting from the above-explained zero-quantity calibration by means of regression calculation in order to avoid learning of a

Nullmengenkalibrierwert.es to improve.

A method for regulating and adapting pre-injection quantities is known from DE 10 2004 001 1 19 A1 (pressure sensor method). In this case, the subsets of the injection are determined by means of a pressure sensor, which is arranged on a cylinder, from the pressure curve during combustion, the so-called heating process, and regulated to nominal values.

From DE 10 2006 026 640 A1 a method is also known with which in operating conditions of an internal combustion engine in which differences and / or fluctuations of the rotational speed essentially depend on a combustion position, the time of fuel injection for reducing the differences and / or fluctuations is adapted ,

Disclosure of the invention

The problem underlying the invention is solved by a method according to claim 1. Advantageous developments are specified in subclaims. Features which are important for the invention can also be found in the following description and in the drawings, wherein the features, both alone and in different combinations, can be important for the invention, without being explicitly referred to again. A basic idea of the invention is a first known

"Pressure sensor method" so with a second known method, the so-called "zero quantity calibration", to combine that the main disadvantages of both procedures, namely the high costs by additional

Pressure sensors with evaluation circuit and software in the pressure sensor method, as well as a high application cost in zero-quantity calibration, are largely avoided.

In this case, a cylinder of the internal combustion engine is provided with a pressure sensor according to the invention. For this "lead cylinder" or an injector associated with the lead cylinder, first of all, in a first step, a pre-injection of fuel is regulated and adapted by means of the pressure sensor method

Driving time known in which the injector a desired

Fuel quantity injected into the guide cylinder. Because the amount of fuel injected depends inter alia on a rail pressure, the first step is carried out for various discrete rail pressures. The drive durations determined in this way are stored non-volatilely in a data memory of a control and / or regulating device of the internal combustion engine.

In a second step, the injector of the guide cylinder is driven constant with the drive duration, which was determined and adapted in the first step. In this case, according to the second method of Nullmengenkalibrierung quantity replacement signals, such as a

Speed variation of the crankshaft, measured and dependent on the

Driveline parameters, comprising a speed of the internal combustion engine and a transmission ratio of a transmission stored in a learning map and non-volatile stored in a data memory of the control and / or regulating device.

In a third step of the method according to the invention, all further cylinders or the injectors assigned to the cylinders are actuated in accordance with the zero quantity calibration and a resulting one

Quantity replacement signal determined. In this case, the quantity replacement signal of the guide cylinder or of the lead injector determined in the second step is used as the desired value. If the volume replacement signal of the cylinder to be calibrated reaches the Setpoint, the associated control period or the difference is stored to a nominal value non-volatile and used analogously to the prior art in the fired operation of the internal combustion engine for drift compensation. Furthermore, it is proposed that the first step and the second step take place simultaneously. The regulation and / or adaptation of the actuation duration according to the pressure sensor method in the fired operation of the internal combustion engine presupposes that the distances between the partial injections must be selected to be large in order to achieve an unambiguous assignment of the pressure curve or the heating profile to the respective injection. Therefore, the soft

Distances between the partial injections usually of an optimum of the internal combustion engine with respect to emission behavior, specific

Fuel consumption and / or smoothness. In contrast, the control and / or adaptation of the activation duration for the guide cylinder takes place very quickly, because of the optimum conditions, so that the much slower adaptation of the drive train parameters can take place simultaneously. As a result, a duration of the method according to the invention is advantageously reduced.

Another embodiment is that in the first step the

Control duration is taken from a characteristic as a function of the rail pressure. In order for different rail pressures to be adapted, it is necessary, at least for a short time, to keep the rail pressure constant for the duration of the first step. Alternatively, a regulation or adaptation of the activation duration in the first step can also take place at variable rail pressure. Here is the

Control duration determined and adapted in an adaptive characteristic as a function of the rail pressure. This advantageously simplifies the operating conditions for the pressure sensor method.

A further refinement is that, in the second step, a ratio of the desired value - quantity replacement signal to a determined actual value of the

Quantity replacement signal is adapted as a function of the drive train parameters. This ratio corresponds to the driveline gain that would have to be applied according to the prior art in the zero-quantity calibration. To this

Way, the inventive method reduces the application effort. In addition, it is proposed that in the second step, at the same time as a first test injection of a first injector with a first actuation period into the first cylinder, a second test injection of a second injector with a second actuation duration into a second cylinder take place

Quantity replacement signal is detected as a superposition of a first excitation by the first cylinder and a second excitation by the second cylinder is reconstructed from the first excitation and the second excitation and the respective activation duration of the respective injector is assigned to the first cylinder by means of pressure sensor method in the first step first injected

Fuel quantity is determined that this first injected amount of fuel serves as a reference, and that from the second excitation by means of the reference, a second amount of fuel that was injected during the second driving time of the second injector into the second cylinder is calculated.

The determination of learning values according to the invention can be carried out as in the case of

Zero quantity calibration according to the prior art in overrun mode. However, the proposed method with respect to the learning process is carried out independently on two injectors in parallel. Out of everyone

Test injection of the two injectors gives an excitation of the

Drive train. These suggestions, as parallel or at least approximately the same time, are superimposed on the drive train. A corresponding

Speed signal evaluation determines a total excitation with magnitude and phase. From this, the excitation of the individual injectors can be reconstructed according to the principle of vector addition. On the basis of the quantity replacement signal reconstructed for the respective injector, a calibration then takes place independently for each injector, as in a zero quantity calibration according to the prior art. The advantage of the method according to the invention is the

Possibility to double the calibration speed without one

Deterioration in signal-to-noise ratio must be accepted.

If one of the injections on the guide cylinder, an injected fuel quantity is calculated for this by means of the pressure sensor method. With this fuel quantity as a reference value can then be reconstructed from the

Quantity replacement signal of the second injection injected thereby

Fuel quantity to be determined. Thus, the inventive method a possibility ready to determine absolute injected fuel amounts, without performing a complex drive train adaptation according to the second step described above.

The inventive method works even better when the

Zero quantity calibration is performed in overrun mode or during startup and / or discharge of the internal combustion engine.

According to the invention, the zero quantity calibration is preferably carried out in the outlet of the internal combustion engine. In order to achieve the conditions for the injector to be calibrated before an engine stalls, the regular shutdown of the injection takes place only with the injector in the injection order before the injector to be calibrated, and not necessarily with the shutdown of the ignition or injection directly following injector. If after switching off the ignition or the

Injection, the engine continues to rotate more than the working range of a cylinder, the zero quantity calibration can be performed for more than one cylinder or the associated injectors

In principle, the method according to the invention can also be carried out during a startup phase or startup phase of the internal combustion engine. Here, starting from a position detection of the stationary internal combustion engine, for example, from the previous phase-out, the next possible cylinder can be injected and ignited determined and applied for this cylinder or the associated injector Nullmengenkalibrierung.

Subsequently, the normal, known from the prior art,

Start function for the next cylinder according to the injection order performed. For conventional drive concepts with internal combustion engines, the advantage of the method according to the invention is a shortening of

Calibration time during the overrun phase. For alternative drive concepts that allow a shutdown of the internal combustion engine, such as the purely electric driving parallel hybrid drive or a so-called "sailing" when the engine is switched off, are no overrun phases for a

Zero quantity calibration according to the prior art available. The The invention therefore offers a possibility of carrying out a zero-quantity calibration without an overrun phase.

In addition, it is proposed that in the first step for the first cylinder, the first activation duration of the first injector is determined by means of zero quantity calibration. It is in the start-up phase and / or phase-out of the

Internal combustion engine determines a first drive duration of a first injector. According to the invention, the drive train parameters are then adapted in the second step with the first activation duration thus determined, so that the set replacement signals determined in the second step serve as reference values for the calibration of the further cylinders or the associated injectors. As a result, it is possible to dispense with the expensive equipment of the guide cylinder with pressure sensors. It goes without saying that the reference value of the first cylinder also in the above-explained parallel or approximately simultaneous

Injection into two cylinders can be used. Wherein the reference value is not determined by the pressure sensor method, but by means of the zero quantity calibration in the start-up phase and / or phase-out

Internal combustion engine.

Other features, applications and advantages of the invention will become apparent from the following description of embodiments of the invention, which are illustrated in the figures of the drawing. All described or illustrated features alone or in any combination form the subject matter of the invention, regardless of their

Summary in the claims or their dependency and regardless of their formulation or representation in the description or in the drawing.

Show it:

Figure 1 The environment of the invention

Figure 2 is a flow chart of the method according to the invention FIG. 3 is a graphic representation of a superposition of two amplitude signals

FIG. 4 shows a control duration characteristic diagram of a second injector which has been calibrated according to the invention together with a first injector

FIG. 5 shows a control duration characteristic diagram of a first injector which has been calibrated according to the invention together with a second injector

Figure 6 is a graphic representation of a superposition of two amplitude signals which lie to each other so that they include an angle τ, which is not equal to a multiple of 90 °

Figure 7 is a graphical representation of a phase-out of a

Internal combustion engine

FIG. 8 is a graphical representation of different stop positions in FIG

Dependence of a position of a throttle valve

Figure 9 is a graphical representation of a starting phase of an internal combustion engine and

Figure 10 is a graphical representation of the relationship between a set replacement signal and a pressure sensor signal.

In FIG. 1, an internal combustion engine bears the reference numeral 10 as a whole. It serves to drive a motor vehicle, not shown, and comprises four cylinders 12a to 12d with four combustion chambers 14a to 14d. Each combustion chamber 14 a to 14 d has an inlet valve 16 a to 16 d, which are connected to an intake pipe 18. Combustion air passes into the respective combustion chamber 14a to 14d via the intake pipe 18 and the intake valves 16a to 16d. in the

Intake manifold 18 is a throttle valve (not shown) arranged. By means of the throttle valve, the amount of combustion air that enters the respective combustion chamber 14 a to 14 d, depending on an operating condition of the internal combustion engine 10 is set. Fuel is injected into the combustion chambers 14a to 14d via an injector 20a to 20d, respectively. The injectors 20a to 20d are connected to a high-pressure fuel storage 22, which is also referred to as "rail" connected.

The fuel-air mixture in the combustion chambers 14a to 14d is ignited after the compression stroke; either by spark ignition or

Self-ignition. The hot combustion gases are discharged from the combustion chambers 14a to 14d via exhaust valves 24a to 24d in an exhaust pipe 26. This leads to an exhaust system 28, which cleans the exhaust gas by chemical conversion of the pollutants contained therein. Alternatively, or parallel to the throttle valve in the intake manifold 18, and an exhaust gas passage in the

Exhaust pipe 26 may be arranged with the combustion air amount is set in the combustion chambers 14 a to 14 d.

During operation of the internal combustion engine 10, a crankshaft 30 is rotated, whose speed or rotational speed and

Spin is detected by a high-resolution crankshaft sensor 32.

A fresh air mass flowing via the intake pipe 18 to the combustion chambers 14a to 14d is detected by an air mass sensor 34. Furthermore, at the

Internal combustion engine 10, a combustion chamber pressure sensor 36 is arranged, which detects the pressure in the combustion chamber 14d. This cylinder 12d is referred to as a "master cylinder".

The operation of the internal combustion engine 10 is controlled by and / or

Control device 38 controlled and / or regulated. This receives signals from, inter alia, the crankshaft sensor 32, the air mass sensor 34 and the combustion chamber pressure sensor 36. Controlled by the control and / or regulating device 38 among other things, the injectors 20. It should be noted at this point that whenever a component of the Index a to d is not explicitly mentioned, the corresponding explanations for all

Components a to d apply.

An amount of fuel Q injected into the combustion chambers 14 from the injectors 20 is proportional to a drive duration T at constant pressure the injectors. The amount of fuel Q further influences

cylinder-specific torque M, which acts on the crankshaft 30.

FIG. 2 shows a flowchart of an embodiment of the invention

inventive method. First, in a step 40, a pre-injection is controlled and adapted according to the pressure sensor method for the guide cylinder 12d known, for example, from DE 10 2004 001 1 19 A1. Thus, for the guide cylinder 12d, a drive _duration t _{before L is} known, which is so dimensioned that a desired amount of fuel is injected into the guide cylinder 12d via the drift-laden injector 20d of the guide cylinder 12d. This control duration tvorL is determined separately for different rail pressures and the results obtained non-volatile in a data memory of the control and / or

Regulator 38 filed.

According to the invention, the first step 40 can take place both during a "fired" operation, ie with injection of fuel, and during a coasting phase, for which the intervals between the partial injections are chosen to be so great in that the individual partial injections can be unambiguously assigned to a determined heating course in the cylinder 12.

For the regulation of the first activation _duration t _{before L} according to the pressure sensor _method , it is necessary in the prior art to increase the pressure in the

Keep fuel high pressure accumulator 22 constant for the duration of the process. According to the invention, the control can also take place at variable rail pressure. For this purpose, the first drive time t _{L is} not determined at different discrete rail pressures, but determined and adapted from an adaptive characteristic as a function of the rail pressure. In this case, a regression analysis can be performed to determine the characteristic.

In a second step 42, the injector 20d of the guide cylinder 12d is constantly driven with the drive _duration t _{before L} determined previously in the first step 40. In this case, after the z. B. from DE 10 2008 002 482 A1 Procedure of "zero quantity calibration", depending on the so-called

Driveline parameters, in particular the crankshaft speed and the

Translation ratio, so-called set replacement signals S determined and stored in a map.

The quantity replacement signals S may have the rotational nonuniformity of

Crankshaft characterizing size, an output of a lambda probe or an output of an ion current probe be. Instead of

Quantity replacement signal S can also be a ratio between a fixed setpoint and a measured actual value of the set replacement signal S depending on the drive parameters are adapted. This ratio corresponds to one

Driveline reinforcement, which would have to be applied according to the prior art. The invention eliminates the application of the drive train reinforcement.

Because the first step 40, the regulation of the first actuation _duration t _{before L} by means of pressure sensor _method , is very fast due to the optimal conditions, the second step 42, the comparatively slower adaptation of the drive train parameters, can take place simultaneously.

In a third step 44, all cylinders 12a to c, except for the master cylinder 12d, are actuated according to the known method of "zero quantity calibration" and the quantity replacement signal S. The procedure is that the quantity replacement signal S previously determined in the second step 42 is used as setpoint In this case, the activation _{duration tz of} the cylinders 12 is varied until the measured quantity _{replacement signal} S reaches the desired value The associated activation period T or a difference to a nominal value of the activation period T is stored non-volatilely in a data memory of the control and / or regulating device 38 ,

The second step 42, the adaptation of the drive train parameters, can

be bypassed according to the invention by simultaneously with a test injection to the master cylinder 12d, a second test injection into another cylinder 12 takes place. In this case, a set replacement signal S is determined, which results from the Superposition of a first set replacement signal S, triggered by the

Test injection into the master cylinder 12d, and a second set replacement signal S, triggered by the second test injection into another cylinder 12 results.

FIG. 3 shows, as part of an embodiment of the method according to the invention, a reconstruction of set replacement signals S of two injectors 20 subjected simultaneously to respective test injections from a measured quantity replacement signal S, for example an excitation of oscillatable components of the drive train within an internal combustion engine 10.

In the present case, it will now be assumed using the example of an internal combustion engine with four cylinders that the two injectors 20 loaded with test injections or the correspondingly assigned cylinders 12 are orthogonal to one another. Accordingly, the first injector 20d or the associated

Guide cylinder 12d characterized by the ordinate axis, while the second injector 20 and cylinder 12 is represented by the abscissa. The now measured oscillation is first represented by an amplitude A12 and a corresponding phase position α. This can be done, for example, as Fourier transformation of a corresponding speed signal.

The respective phases of a pure excitation or oscillation on the

Guide cylinder 12d or the second cylinder 12 are known in the art and are used in the coordinate system shown here as axes. The measured signal with the amplitude A12 and phase α is then projected on the two axes 1 and 2 by means of the trigonometric functions:

A1 = A12 ^" sin (a)

A2 = A12 · cos (a) With:

A12: Amplitude of the total vibration that is, the superposition of the two vibrations caused by the respective injectors

A1: the reconstructed amplitude of guide cylinder 12d

A2: the reconstructed amplitude of cylinder 12

a: Phase (phasing) or phase shift of the measured excitation A12 with respect to the phase of cylinder 12 or guide cylinder 12d.

As a result, the two individual excitations of the injectors 20d and 20 causing the overall excitation can be separated in a simple manner.

Then, for each of the two injectors 20, the first injector 20d and the second injector 20, an algorithm according to the prior art is performed, wherein a drive duration of each injector 20 is tracked until a predetermined target amount is reached and then it becomes determined a prior learning value according to the prior art.

FIG. 4 shows a test result which was obtained on a motor vehicle with a four-cylinder internal combustion engine after carrying out the method according to the invention. In this case, a received drive characteristic map 45 of a second injector 20 was determined three times. The respective drive duration of a first injector 20d was used as a parameter and took the

Activation time 140 μβ, 180 μβ and 220 μβ.

The three determined actuation duration curves 45a, 45b and 45c are in this case entered in a graph which shows a specific set replacement signal S2 of the second injector 20 over the actuation period T, measured in .mu.β. Here, the Ansteuerdauerkennfeld 45a represents the Ansteuerdauerkennfeld the second injector 20 at a drive duration of the first injector 20d of 140 s. The drive duration map 45b was recorded at a drive duration of the first injector 20d of 180 s and the drive duration map 45c was for a drive duration of the first injector 20d of 220 μβ

added. The three determined drive duration maps 45a, 45b and 45c of the second injector 20 lie exactly within the measurement accuracy of the speed evaluation method used.

FIG. 5 shows a diagram for corresponding drive duration characteristics of the first injector 20d, with the injector 20d and the injector 20 having "exchanged" their roles here, as it were, with respect to FIG

Diagram, a respective particular set replacement signal S1 of the first injector 20d over the control period T, measured in μβ, applied. The drive duration of the second injector 20 was used as a parameter and was for drive duration map 45a '140 s, for drive duration map 45b' 180 s and for drive duration map 45c '220 s.

Here, too, the three drive duration characteristic maps 45 'determined for the injector 20d lie exactly on top of each other within the measurement accuracy of the speed evaluation method and thus prove the accuracy of the inventive device

Process.

As an alternative to the aforementioned scenario, in which two orthogonal injectors 20d and 20 or corresponding guide cylinders 12d and cylinder 12 are subjected to respective test injections, it is also possible to excite two injectors 20 and cylinders 12 which are in opposite directions. The two

Vibrations extinguish when the injection quantities for the respective injectors 20 are equal. This can be used, for example, to exactly match two injectors 20 if an absolute value of the respective injection for which the adjustment is made is not relevant.

FIG. 6 now shows a method according to the invention

made reconstruction of respectively excited by a first injector 20d and a second injector 20 vibrations from a resulting from the two oscillations resulting total vibration. there Injectors 20d and 20 form an angle τ which is not equal to an integer multiple of 90 °.

Similar to Figure 3, this constellation is also in one

Coordinate system shown, wherein the second cylinder 12 and injector 20 is drawn on a horizontal axis and the guide cylinder 12d and the first injector 20d on a relative to the horizontal axis rotated by the angle τ axis. The axes of this coordinate system therefore include an angle τ. The measured signal is in turn converted into a representation with amplitude and phase and drawn accordingly in this coordinate system. In this case, the amplitude A12 is entered at an angle α to the injector 20. A reconstruction of the individual amplitudes A1 and A2 results here by applying the sine theorem analogous to the

Reconstruction in Figure 3. This results in a generalized

Evaluation relationship as follows:

A1 = A12 ^■ sin (a) / sin (180 ° - τ)

A2 = A12 ^■ sin (τ-α) / sin (180 ° -τ)

Because the amount of fuel injected during the test injection is calculated for the master cylinder 12d according to the pressure sensor method, a quantity of fuel injected into the second cylinder 12 during the second test injection can be calculated from the detected quantity substitute signals S as the reference value. As a result, the drive train application can be omitted.

According to the state of the art, it is necessary to carry out a zero-quantity calibration during a coasting phase of the internal combustion engine 10. An embodiment of the method according to the invention allows a

Shifting the Nullmengenkalibrierung in a phase-out, after switching off the ignition of the internal combustion engine 10. It is also conceivable to carry out the zero quantity calibration in a start-up phase or start phase of Internal combustion engine 10, whereby the start-up phase by at least one

Cylinder segment is extended.

FIG. 7 shows in a diagram an outlet of the internal combustion engine 10 without injection of fuel when the throttle valve 19 is open and closed. The angle of the crankshaft is plotted in ° CA on the abscissa axis; the ordinate is the speed in revolutions per minute. When the throttle valve 19 is open (curve 46), the gas exchange torques of the individual cylinders 12 dominate over the friction torques and moments of inertia. Through the open throttle 19 flows against a closed

Throttle 19 more air into the cylinder 12, whereby a maximum pressure in the cylinder increases. The higher maximum pressures in the cylinders 12 lead to a rotational nonuniformity of the crankshaft, wherein the gas torque built up by the last compressing cylinder 12 before the zero crossing of the rotational speed becomes so large that it comes to a reversal of direction and the internal combustion engine 10 compresses the previously compressed cylinder 12, until it comes again to the direction of rotation and the internal combustion engine 10 is finally.

When the throttle valve 19 is closed (curve 48), less air flows into the cylinders 12 and as a result the maximum pressures in the cylinders 12 are reduced. The speed curve is more uniform and there is no reversal of the direction of rotation before the internal combustion engine stops. The

Gas exchange torques are small compared to the moments of inertia and friction moments.

Figure 8 shows a diagram of an influence of the throttle position on a stop position of the internal combustion engine 10. The abscissa, the consecutive numbers of the tests are plotted. The ordinate shows the crank angle in ° KW before the ignition TDC.

When the throttle 19 is closed (dashed connecting line), the stop positions of the internal combustion engine 10 scatter between bottom dead center (180 ° KW before ignition TDC) and ignition TDC (0 ° CA before ignition TDC). Consequently, when the throttle valve 19 is closed, no adjustment of the stop position is possible. In contrast, there is a kind of open throttle valve by the increased gas exchange moments and the two-way reversal

Balancing position at approx. 90 ° KW before ignition TDC in which all cylinders 12 are at the same level. Line 50 shows that the deviation from the compensation position is approximately 10 ° CA in all tests.

The zero quantity calibration starts at a drive duration, which certainly does not lead to an injection of fuel. At each phase out the

Increased control duration incrementally until it comes to a combustion injection. Detection takes place by comparing the measured

Quantity replacement signal S, in this case the signal of the crankshaft sensor 32, with a reference speed signal (see Figure 7), in which certainly no

Injection and combustion takes place. In this case, differentiation-forming methods and / or evaluation of the rotational speed gradients can take place and / or comparisons of rotational speed patterns can be used.

In order to achieve the conditions for a zero quantity calibration for the respective injector 20 in the phase-out phase before the internal combustion engine 10 has come to a standstill, it is conceivable that the regular injections after switching off the ignition not with the first following cylinder 12th

to shut down, but continue the injections and thus the combustion and to end only with the injection in the order before the injector 20 to be calibrated or the associated cylinder 12.

If the internal combustion engine 10 continues to rotate by more than one cylinder 12 after switching off the ignition and switching off the injection, the zero quantity calibration is carried out for the following cylinder 12 or the associated injector 20. It is also possible to carry out the zero-quantity calibration in a start-up phase or start-up phase of the internal combustion engine 10. Here, starting from a position detection of the stationary internal combustion engine 10, for example, from the previous phase-out, the next possible cylinder 12 can be injected and ignited in the determined. The zero quantity calibration is applied to this cylinder 12 or to the injector 20 assigned to it. Subsequently, the normal starting function known from the prior art is applied to the next cylinder 12 in the firing order.

A reference speed signal belonging to the starting phase is shown in FIG. 9. The illustrated speed curve as a function of the crank angle is calculated as a function of a constantly applied starting torque.

At a starting torque of 45 Nm at full charge of the first cylinder 12, a first top dead center is not reached. The kinetic energy of the internal combustion engine 10 is not sufficient to be in the range of high

Gas exchange torque at about 160 ° KW to turn the first compacting cylinder 12 through its top dead center (180 ° CA). The internal combustion engine stops.

The reference speed signal is improved by measuring and storing further associated data, such as engine friction as a function of temperature, drive duration of the injectors, starter speed (for the zero-level calibration in the starting phase), position of the throttle 19, and others. The more accurate the reference speed signal, the safer and better is the zero-quantity calibration.

It goes without saying that instead of the speed signal of a

Crankshaft sensor 32 and the signal of a combustion chamber pressure sensor 36 for a zero quantity calibration in the so-called start and / or stop operation of the internal combustion engine 10 can be used. FIG. 10 shows the measured relationship between the quantity replacement signal S from FIG Nullmengenkalibrierung, represented on the ordinate axis and the signal from the pressure sensor method shown on the abscissa axis. There is a direct / linear relationship, so that both signals can be considered equivalent.

Claims

claims

1 . Method for controlling an internal combustion engine (10) comprising the following steps:

In a first step (40), by means of the pressure sensor method for a first injector (20d), a first activation _duration (t _{before L} ) is determined, in which a desired amount of fuel is injected into a guide cylinder (12d), and stored;

in a second step (42), the first injector (20d) is driven with the first drive _duration (t _{before L} ) and a resulting one

Quantity replacement signal (S) is stored and stored as a function of the drive train parameters in a learning map;

in a third step (44), a control period (T) of the injectors (12) assigned to the cylinders (20) is varied by means of a zero quantity calibration for all further cylinders (20) until the quantity replacement signal (S) determined in the second step (42) Setpoint value is reached, wherein the thus determined drive time (T) is stored.

2. Method according to the preceding claim 1, characterized in that the first step (40) and the second step (42) take place simultaneously.

3. The method according to any one of the preceding claims, characterized

characterized in that in the first step (40) the activation duration is taken from a characteristic as a function of the pressure in a high-pressure fuel accumulator (22).

4. The method according to any one of the preceding claims, characterized

characterized in that in the second step (42) a ratio of the setpoint value of the quantity replacement signal (S) to a determined actual value of the

Quantity replacement signal (S) is adapted as a function of the drive train parameters.

5. The method according to any one of the preceding claims, characterized

characterized in that, in the second step (42), a second test injection of a second injector (20) with a second actuation duration (T) takes place simultaneously with a first test injection of a first injector (20d) with a first actuation time (T) into the guide cylinder (12d). takes place in a second cylinder (12) and a resulting quantity replacement signal (S) as a superposition of a first excitation by the guide cylinder (12d) and a second excitation by second cylinder (12) is detected that from the set replacement signal (S), the first excitation and the second excitation is reconstructed and the respective actuation duration (T) of the respective injector (20) is assigned, that for the guide cylinder (12d) in the first step (40) by means of pressure sensor method, a first injected fuel quantity is determined that this first injected fuel quantity as Reference serves, and that from the second excitation by means of the reference, a second fuel quantity, during the second Drive period (T) of the second injector (20) was injected into the second cylinder (12) is calculated.

6. The method according to any one of the preceding claims, characterized

characterized in that the zero quantity calibration is performed in a coasting operation, a start-up and / or an outlet of the internal combustion engine (10).

7. The method according to the preceding claim 5, characterized in that a shutdown of the injections after switching off the

Internal combustion engine (10) only upon reaching the injector (20), which is in the injection order in front of the injector (20) to be calibrated, takes place.

8. The method according to the preceding claim 5, characterized in that in a start-up of the internal combustion engine (10) starting from a

Position detection of the stationary internal combustion engine (10), a next cylinder (12) into which can be injected and ignited, is determined and a, this cylinder (12) associated injector (20) is calibrated.

9. The method according to any one of the preceding claims, characterized

characterized in that in the first step (40) for the guide cylinder (12d) the first drive _duration (t _{before L} ) of the first injector (20d) by means of

Zero quantity calibration is determined

10. Computer program, characterized in that it is programmed for use in a method according to one of the preceding claims

1 1. Control and / or regulating device (38) for an internal combustion engine (10), characterized in that it is programmed for use in a method according to one of claims 1 to 9.