DE102013213698A1 - Method for operating an internal combustion engine - Google Patents

Abstract

The invention relates to a method for operating an internal combustion engine of a motor vehicle, which has a fuel reservoir (26) with a pressure sensor, wherein fuel from the fuel reservoir (26) injectors (28) is supplied, wherein a correlation between pressure values of a pressure of the fuel in the Fuel accumulator (26) and current values of an injector of at least one injector (28) is learned adaptively to determine an adjustable injector, wherein when this is set, there is a digital jump in quantity in the range of a critical pressure.

Description

The invention relates to a method and an arrangement for operating an internal combustion engine in a motor vehicle.

State of the art

An injection system with a fuel storage (rail) is also referred to as a common-rail injection system. This injection system is designed to respond when certain errors occur when switching from normal operation to emergency operation (Limp-Home). In this case, the injection position can be operated in normal operation according to their specifications without restriction. In emergency operation, on the other hand, it is provided that functions of individual components of the injection system and / or operating parameters are restricted. Thus, a permissible value range of an operating parameter, which is limited by a minimum and / or maximum setpoint value, can be limited for the emergency driving operation in comparison to the normal operation.

Furthermore, the injection system for determining the pressure of the fuel in the fuel accumulator on a fuel storage pressure sensor or rail pressure sensor (RDS). If the fuel storage pressure sensor should fail, can be initiated as a fault reaction by a high-pressure pump of the injection system full delivery of fuel at elevated pressure (Pressure Increase). After an applicable waiting time, the injection quantity of fuel can be switched off for a short time (pressure shock) in order to achieve a rapid increase in the pressure of the fuel in the fuel accumulator to an opening pressure level of the pressure limiting valve. If an opening of the pressure-limiting valve then succeeds, a desired pressure for the fuel provided for the emergency driving operation of the pressure-limiting valve is set, which corresponds to approximately half the nominal pressure of the injection system.

Due to an insufficient high-pressure balance, it is possible that the pressure limiting valve of the injection system only opens safely when the engine has reached a certain speed, because the intended opening pressure of the pressure relief valve is not reached otherwise. In the event of a failure of the fuel storage pressure sensor, which is to be classified as an error case, the opening of the pressure relief valve can no longer be checked via the signal for the pressure in the fuel accumulator. Therefore, in this injection system, depending on the operating point in which the error occurs, shut off in unsecured opening the pressure relief valve of the engine to prevent undefined and thus potentially critical operation of the engine. Depending on the injection system, this can represent a significant limitation of the emergency driving capability in the event of a failure of the fuel-pressure sensor.

In case of failure of the fuel storage pressure sensor can be used as an evaluation criterion for opening or non-opening of the pressure relief valve, a change in the temperature of an injector solenoid of an injector or a return of fuel in the pressure relief valve. In torque-controlled applications, a change in the speed of the internal combustion engine or in speed-controlled applications, a change in a controller profile of the engine speed and / or a curve of a desired injection quantity can be used as an evaluation criterion for the opening or non-opening of the pressure relief valve.

If a non-opening of the pressure limiting valve is detected on the basis of these approaches, the internal combustion engine is usually switched off. Only when the pressure relief valve is opened does the internal combustion engine continue to run in emergency operation.

A function of the pressure relief valve depends inter alia on a pressure of the fuel, which can be determined directly or indirectly. In this regard, the publication DE 10 2008 000 983 A1 from which a method for controlling a fuel metering system is known, which comprises at least one injector for injecting fuel into an internal combustion engine. In this case, the at least one injector is supplied with a current value, wherein at least on the basis of the current value, a value of the rail pressure is determined.

Disclosure of the invention

Against this background, methods according to claim 1 and 8 and an arrangement with the features of claim 11 are presented. Further embodiments of the invention will become apparent from the dependent claims and the description.

The method is u. a. an adaptive learning function for determining a pressure, i. H. a so-called rail pressure, of fuel in a fuel reservoir of an injection system based on an injector flow through at least one injector of the injection system, which may include an injection valve provided.

It can during an operating time, usually before a failure of a commonly used fuel storage pressure sensor of the fuel accumulator, ie as long as the fuel storage pressure sensor of the fuel accumulator Signals are available, a correlation between a profile of the pressure of the fuel and an injector flow profile of the injector determined and learned in a learning process. For this purpose, in selected operating points, usually in stationary load points, z. B. idle, a pressure profile for the pressure in the fuel storage with the injector flow profile of the at least one injector are correlated. Basically, the learning process in the factory, eg. At the end of the tape to be performed.

At a given pressure in the fuel storage, a so-called digital jump in quantity can be generated at the at least one injector by adjusting the injector flow profile. Starting from a high level and / or high injection injector current value, where injection is assured, lowering the injector current to a low, injection preventive value at which no more injection is stopped and / or the injection amount is significantly changed, the digital jump in quantity brought about.

Also, from a low injection-inhibiting value of the injector flow at which no injection occurs, the injector flow may be increased until a high injection-guaranteeing value is reached until injections commence. In this way, the pressure of the fuel in the fuel storage can be correlated to the value and / or level of the injector flow at which the digital quantity jump takes place and / or determined. This correlation can be determined for one injector, several or all injectors of the injection system, either periodically or continuously. In the method, the value of an adjustable injector current is learned in which, when this is set, there is a digital quantity jump in the region of a critical pressure.

Depending on the concept for quantity detection, it can be selected whether an injection should fail or an injection should start again. It is provided in the context of the method, the injector flow starting from a level at which injections take place, to a level at which injections fail to lower gradually at a defined pressure. Furthermore, starting from a level at which no injections take place, the injector flow may be gradually increased at a defined pressure to a level at which injections take place and / or use. For adaptive learning between the pressure and the injector flow, regardless of whether the injector flow is now lowered or increased, those levels and thus values of the injector flow are taken into account where a functional state of the injection system changes. A change in the functional state results at a first level and thus a first value, in which, depending on a change in the injector flow, a change from a functional state with injections taking place to a functional state with injections that do not take place results, and at a second level or second value, which in turn results from non-occurring to occurring injections. For correlation, these two levels of injector current, where a change is made between the functional states, are used. Accordingly, to determine the digital quantity jump as well as to provide the correlation, the injection-ensuring and / or the injection-preventing value of the injector stream can be used. In order to achieve the digital jump in quantity, the injector flow has to be changed in a range with a resolution of 400-800 bar / A, whereby an absolute level of the injector flow depends on the pressure.

In this case, a certain spread for the value of the injector, in which the digital jump in quantity takes place, can be taken into account. By learning with an active pressure sensor of the fuel accumulator an influence of tolerances of the components of the injection system is reduced to the correlation. Since the learning is carried out with the respectively installed in the internal combustion engine and / or the engine associated control unit, the fuel storage pressure sensor and the injectors, an influence of tolerances of the controller and the injectors can be reduced to a behavior of the correlation or even eliminated.

A dynamic influence on the correlation can still be taken into account, which results in a certain, much smaller spread of the value of the injector current at which the digital quantity jump results.

The omission or onset of injection as well as a significant change in the amount to be injected during injection with a variation of the injector flow and / or the injector flow profile may be accomplished by a detection method, for example based on a change in the speed of the engine or a change in the speed governor, e.g. B. an idle or Alldrehzahlreglers, the internal combustion engine can be detected.

In one possible application, a controlled emergency driving operation is then carried out as an error reaction, provided that in the event of a failure of the fuel-storage pressure sensor in at least one operating region of the internal combustion engine, an opening of the pressure-limiting valve, for. B. due to a Quantity balance or component tolerances, is not ensured. In this case, a control of the pressure by a control loop with the fuel storage pressure sensor as the sensor and the metering unit of the high pressure pump or other suitable actuator in the high pressure region of the injection system as an actuator to a controlled emergency operation, the metering unit operated as an actuator controlled instead of regulated is without a sensor signal for the actual pressure in the fuel tank is required.

The intended controlled emergency operation can also be performed in injection systems that have no pressure relief valve. In addition, in the controlled emergency operation, the pressure of the fuel can be controlled to a designated target pressure. Depending on a tolerance position of the components in the high-pressure region of the injection system, eg. B. depending on a high-pressure delivery of the high-pressure pump and / or dependent on a removal amount through the injectors, a deviates from the intended target pressure actual pressure for the fuel.

In controlled emergency operation, the learned correlation between the injector flow profile of at least one injector and the course of the pressure and / or the pressure profile of the fuel in the fuel storage can be used as a basis for a continuous or periodically recurring adaptation of the pressure in the fuel storage, wherein a control of a delivery of a fuel pump the injection system is adjusted accordingly. In this case, in an embodiment, the delivery rate of a high-pressure pump designed as a fuel pump, which is arranged in the high-pressure region of the injection system, controlled. With this high pressure pump, the pressure of the fuel within the fuel reservoir can be changed and / or adjusted.

By this measure, the deviation of the actual pressure from the target pressure in the controlled emergency operation can be reduced. In addition, thus, for example. Aging effects of the components, eg. B. a reduction in the flow rate of a pump, eg. The high-pressure pump, over the life, can be compensated

In one embodiment of the emergency driving operation, at least one injector is adjusted to a level of pressure taking into account a previously learned correlation between the pressure and the injector flow, by which a critical overpressure in emergency driving operation is reliably avoided. To set the level of the injector flow intended for this purpose, it is taken into account that it is so low that no injection is carried out. If an injection results for this at least one injector in controlled operation and / or emergency driving operation, an intended threshold or an intended level of pressure is exceeded. In this case, a control value for the fuel pump is adapted, usually reduced.

The method can be used in different operating areas of the injection system. An application in the context of the controlled emergency operation is only one conceivable variant.

In the described application, it is possible that the internal combustion engine does not have to be turned off when the pressure sensor of the fuel accumulator fails. This application can be implemented in an operating area in which an opening of the pressure relief valve is not ensured in any case, or in injection systems without pressure relief valve. Usually, opening the pressure relief valve is not a necessary requirement for emergency operation. Thus, an unconditional or conditional shutdown of the engine can be avoided. Furthermore, the availability of the internal combustion engine can be significantly increased in the event of a failure of the fuel storage pressure sensor.

In an implementation of the method, values for the injector flow which flows through the at least one injector in normal operation during learning of the correlation as well as in emergency operation can be varied. Resulting changes in values of pressure, which usually can result in a digital jump in quantity, can be used to determine the correlation.

The method may be for an injection system which, in the event of failure of the fuel storage pressure sensor, has only a limited ability to perform an emergency operation that allows only limited loading of a roller cam contact of a fixed displacement (PF) pump, or in an injection system, which has no pressure relief valve, are turned on.

Overall, the pressure or rail pressure in the fuel accumulator can be determined by an adaptive learning function based on an injector flow of at least one injector. This is also possible despite the lack of signal of the fuel accumulator pressure sensor of the fuel accumulator, since the pressure in the fuel accumulator can now alternatively be determined via the correlated with the pressure and / or the pressure profile Injektorstromprofil the at least one injector. In this case, from the information about the rail pressure in the controlled emergency operation, the deviation between the actual pressure and the nominal Reduced pressure and a possibly resulting change in this deviation over a lifetime of the injection system can be corrected.

The method is suitable for an injection system with a fuel storage, which is also referred to as a common rail injection system. If the injection system has only one actuator, a so-called 1-actuator system, the emergency operation is usually realized by a pressure relief valve (pressure relief valve (PLV) = Pressure Limiting Valve) with a Notfahrfunktion, the pressure relief valve are selectively opened via an error response function can. In one embodiment of the method, values of the pressure in emergency driving mode are indirectly determined via values of the injector flow from the learned correlation of the stated values. Thus, the pressure relief valve can remain closed even in emergency driving, the pressure relief valve is only open if the value of the pressure indirectly determined by a value of the injector flow is greater than a target pressure.

In case of failure of the fuel storage pressure sensor can be used as an error reaction in at least one operating range of the engine, in which an opening of the pressure relief valve, z. B. is not ensured due to a balance of quantities or component tolerances, an attempt to open will be omitted. Instead, in an embodiment of the method in a regulation of the pressure of the fuel by a control loop with the fuel storage pressure sensor as a sensor and the metering unit (ZME) of the high-pressure pump or other actuator in the high pressure region of the injection system can be switched to act as an actuator on the controlled emergency operation. In this case, the metering unit can be used for control instead of regulation, wherein a sensor signal provided by the fuel storage pressure sensor for a value of an actual pressure in the fuel storage can be dispensed with.

In the controlled emergency driving the pressure of the fuel is controlled to a designated pressure intended for this purpose, which corresponds at most to the nominal pressure of the injection system. Depending on the tolerance of the components in the high pressure region of the injection system, wherein z. B. a high-pressure flow rate of the high-pressure pump and / or a removal amount are taken into account by the injectors, a deviating actual pressure can be adjusted. For this purpose, a behavior of the injector flow, which flows through at least one injector and is correlated with the pressure, is controlled. For this purpose, a desired injector current correlated with the desired pressure can be compared with a measured actual injector flow.

In order to reduce the deviation of the actual pressure from the target pressure in the controlled emergency driving operation, information from functions that provide an actual tolerance position of the components of the injection system, for. B. the function AMC (Adaptive Mastering Control) for the adapted control of operating parameters, are taken into account in the generation of the drive signal of the metering unit.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Brief description of the drawings

1 shows a first diagram for an operating parameter used in one embodiment of the method.

2 shows further diagrams of the operating parameter used in the embodiment of the method.

3 shows a schematic representation of components of an injection system, for which the embodiment of the method is to be performed, in two different operating situations.

4 shows a first flowchart illustrating the embodiment of the method.

5 shows a second flowchart illustrating the embodiment of the method.

Embodiments of the invention

The invention is schematically illustrated by means of embodiments in the drawings and will be described in detail below with reference to the drawings.

The figures are described in a coherent and comprehensive manner, like reference numerals designate like components.

The in the 1 and 2 The diagrams shown each comprise an abscissa 2 along which a pressure of fuel in a fuel tank of an injection system is plotted in bar. Furthermore, each diagram includes an ordinate 4 along which an injection quantity provided by an injector injector, in cubic millimeters per Injection is applied. In addition, in each of the diagrams from the 1 and 2 a curve 6 for a pressure-dependent injection quantity at a level of an injector flow flowing through the injector, it being provided that at a constant drive duration for the injector at the latter through the curve 6 illustrated pressure-dependent injection quantity and the intended level of the injector current secure injection is ensured.

A second turn 8th in the diagram 1 illustrates a curve of a pressure-dependent injection quantity at a level of the injector flow for a digital jump in quantity for fuel to be injected and / or to be conveyed. In this case, on the one hand, it may be provided that during operation of the injector, when a first low, injection-preventing injector flow flows through the injector, the injector is not opened despite the adjacent low injector flow and thus no injection is carried out. However, if the injector flow provided to the injector is increased from the first low value to an increased injection-ensuring value and thus to the intended level, injection takes place. On the other hand, it is also possible that through the second curve 8th represented pressure-sensitive injection quantity at the level of the injector stream for the digital jump jump by lowering a high, injection-ensuring injector to a low, injection-preventing Injektorstrom to capture, it being provided that when the high injector current to the injector injections are caused, whereas after a reduction of the injector flow to the low injector current injections be omitted.

Like the first diagram 2a shows, in the embodiment of the method that is based on a second, here greatly widened curve 10 represented, pressure-dependent injection quantity at the intended level of the injector for the digital jump in a scatter quantity 12 subjected. When carrying out the embodiment of the method, it is provided that a pressure of the fuel is determined via a fuel-tank pressure sensor during operation of the injection system in the fuel accumulator. Furthermore, values of the injector current flowing through the injector are determined. In doing so, a correlation is learned between values for the pressure of the fuel and values for the injector flow. Through such learning 14 is it possible to have a spread 16 for the digital quantity jump, which, as indicated by the second graph 2a shown in a reduction of a width of a curve 18 for the level of the injector current for the digital jump in quantity.

The two diagrams show pressure-dependent injection quantities. At a fixed, lowered level of the injector flow, a threshold (pressure threshold) results below a narrow range of pressure, below which no injection takes place. From this it can be deduced whether the value of the pressure is above or below the pressure threshold. By prior learning, a sample spread of injectors with respect to a position of the pressure threshold is eliminated because the pressure threshold for an injector with the still functioning rail pressure sensor is determined.

The diagram 2 B shows a first group 70 of curves representing a pressure-dependent injection quantity of an injector at different values of the injector flow. A second group 72 of curves shows a pressure-dependent injection quantity of several different injectors at the same value of the injector flow.

The diagrams basically show injection quantity characteristics of injectors, the quantity being plotted against the pressure, with a fixed activation duration. The first crowd 70 shows variations of the injector current level in 0.5 A steps. With a nominal high current level, the characteristic curve is on the left-hand side, where almost always something is injected, whereby the quantity increases continuously with the pressure. When the current level is lowered, nothing is injected up to a certain pressure. Then the crowd suddenly rises steeply to about the normal level. This point is called a digital jump in quantity. Depending on the current, this is the case at different pressures. The second group 72 shows the steep increase in volume at a fixed stream for different injections. This is where the component tolerances that need to be learned come into play. It should be noted that in the area of digital quantity jump, the increase in the injection quantity does not necessarily have to be designed like a jump function, but rather that the increase can take place in a certain pressure range. As a digital jump in quantity, the property of the course is called quasi-jump.

The 3a and 3b each show in schematic representation components of an injection system 20 in a first operating situation, namely in a so-called normal operation ( 3a ) and in a second operating situation, namely an emergency drive ( 3b ). The injection system 20 includes one as a high pressure pump 22 trained fuel pump, which is a metering unit 24 is assigned for metering an amount of fuel to be delivered. In addition, the injection system includes 20 a fuel storage 26 which is also referred to as Rail. During operation of the injection system 20 will fuel through the high pressure pump 22 pressurized and in the fuel tank 26 stored under increased pressure. The fuel storage 26 here are several injectors 28 assigned to those from the fuel storage 26 pressurized fuel is supplied, the pressurized fuel from each one injector 28 , here's an ampere meter 29 for measuring an injector flow is assigned, in an associated combustion chamber (cylinder) of an internal combustion engine is supplied. During operation of the injection system 20 gets every injector 28 an injector provided via which the respective injector 28 is opened.

In addition, the fuel tank 26 a fuel storage pressure sensor 30 , which is also referred to as a rail pressure sensor assigned. Furthermore, the show 3a and 3b one each as a control unit to be used control unit 32 for controlling, ie for controlling and / or regulating an operation of the injection system 20 is trained. Furthermore, the control unit 32 configured to control steps of the embodiment of the method.

In a regulated normal operation ( 3a ) of the injection system 20 is provided here that the fuel storage pressure sensor 30 is fully functional. In this normal mode are via the fuel tank pressure sensor 30 Values for the pressure of the fuel in the fuel tank 26 detected. Also, values for injector flow passing through at least one of the injectors become simultaneous 28 flows, recorded. In doing so, it is possible to associate with a value of the pressure of the fuel and vice versa a value of the injector flow, wherein a correlation, assignment and / or dependence of the values for the fuel and the values for the injector flow is learned.

If the fuel storage pressure sensor 30 Should fail, is for the injection system 20 like through 3b shown schematically, a controlled emergency operation performed. At this time, the pressure of the fuel in the fuel reservoir becomes high due to the fuel-pressure sensor 30 now no sensor signal is provided by measuring the injector flow passing through the at least one injector 28 flows, over the ampèremeter 29 determined indirectly taking into account the learned correlation between the injector flow and the pressure. In this case, the pressure of the fuel in the fuel tank 26 be adjusted continuously or periodically recurring.

At the same time the injector becomes 28 operated at a lowered level of Injektorstroms, which correlates with a maximum threshold for the pressure to be protected. Thus, the injection system 20 controlled by adjusting the injector, it is avoided that the pressure reaches a value that is greater than the threshold.

The flowchart off 4 includes steps of the method that are performed in a regulated normal operation. It is provided that the fuel storage pressure sensor 30 functional 40 is. Thus, a signal 42 of the fuel storage pressure sensor 30 available. In addition, a detection 44 from operating points for learning a correlation between values of the measured pressure of the fuel in the fuel storage 26 and values of an injector stream passing through the at least one injector 28 flows, learned. A function to be performed in the context of the procedure 46 can for an injector 28 or all injectors 28 be carried out periodically or continuously. When implementing this feature 46 becomes a variation 48 an injector flow profile and thus a variation 48 of the injector stream passing through the at least one injector 28 flows, made. Because of this variation 28 It can come to digital quantity jumps in the context of a detection 50 by omitting and / or establishing an injection for the at least one injector 28 be identified. Finally, a correlation of the values for the injector flow and thus the injector flow profile to values of the pressure and thus to a pressure profile is performed.

As 5 shows is in case of failure 54 of the fuel storage pressure sensor 30 by the embodiment of the method a controlled emergency driving operation 56 bring about. In this case, through the fuel storage pressure sensor 30 no signal is provided for printing. However, in the context of the procedure when implementing a function 58 the correlation learned in normal operation between values of the injector flow passing through the at least one injector 28 flows, and values of the pressure of the fuel in the fuel tank 26 as a starting point for a continuous or periodically adjusting a control of one of the high-pressure pump 22 to be used to promote the amount of fuel. Starting from this, a controlled activation 60 the metering unit 24 the high pressure pump 22 be implemented, whereby the controlled emergency operation 56 is feasible.

The presented method is for determining a pressure of fuel in the fuel storage 26 the injection system 20 the internal combustion engine provided, the at least one injector 28 has, which is acted upon by an injector. The pressure is determined based on the injector flow and taking into account an adaptively learned correlation between the pressure and the injector flow.

During operation of the injection system 20 may be a value for the pressure of fuel in the fuel tank 26 with a fuel storage pressure sensor 30 and a value for an injector flow passing through the at least one injector 28 flows, recorded, for example, measured. Thereby a correlation between several values for the pressure of the fuel in the fuel storage becomes 26 to assigned values of the injector flow of the at least one injector 28 learned adaptively. By providing a learning function for the correlation between the pressure and the injector flow provided in the context of the method, an emergency driving operation is safeguarded.

In the event that the fuel storage pressure sensor 30 fails, may be a value for the pressure in the fuel tank 26 on the basis of the adaptively learned correlation as a function of a value of the injector flow of the at least one injector 28 be determined.

In this case, the digital quantity jump can usually be detected on the basis of a change in a rotational speed of the internal combustion engine.

The presented arrangement for determining a pressure of fuel in a fuel storage 26 an injection system has a control unit 32 , Which is designed to determine the pressure from the injector and taking into account an adaptively learned correlation between the pressure and the injector. The control unit 32 is designed to control steps of the presented method and thus to control and / or regulate.

The controller is further configured to provide a value for the pressure of the fuel in the fuel storage 26 via a fuel storage pressure sensor 30 and a value for an injector stream passing through the at least one injector 28 flows, provide and / or via an ampere meter 29 to measure and thus capture. In addition, the controller 32 adapted to associate a measured and / or detected value of the pressure with a measured and / or detected value of the injector flow in an adaptive learning process, and a correlation between a plurality of values for the pressure of the fuel in the fuel reservoir 26 to assigned values of the injector flow of the at least one injector 28 adaptively learning and storing the adaptively learned correlation for determining the pressure taking into account the injector current.

In an embodiment, the correlation becomes by assigning at least one detected value for the injector flow, which becomes a simultaneously detected value of the pressure of the fuel in the fuel reservoir 26 correlated, learned. In this case, the correlation in a stationary load point and / or operating point, for example, at idle, the internal combustion engine, determined and / or learned periodically or continuously.

The at least one value for the pressure and the value of the injector flow correlated therewith can be measured in the case of a digital jump in quantity for the fuel to be injected, wherein the digital quantity jump is brought about by changing the injector flow. A digital jump in quantity is z. B. caused in one by the injector compared to a normal operation, starting from a high, injection-ensuring value, in which an injection is ensured, is lowered to a low, injection-preventing value, in which an injection is omitted. In this case, the injector stream can be lowered gradually in a learning operation. In emergency mode, the injector current is reduced to a value that correlates to a designated value of the pressure. Alternatively, the digital rich jump is achieved when the injector current is increased from a low injection inhibiting value at which injection is omitted to a high injection ensuring value at which injection is ensured. As a rule, the digital quantity jump can be detected on the basis of a change in a rotational speed of the internal combustion engine. In this case, a curve of the rotational speed at the onset of the digital quantity jump has a kink and / or a discontinuity.

If the fuel storage pressure sensor 30 fails and for the injection system 20 an emergency drive 56 can perform a value for the pressure in the fuel tank 26 on the basis of the learned correlation as a function of a value of the injector flow of the at least one injector 28 be determined.

Further, the pressure may be in consideration of a designated target pressure in emergency driving 56 be controlled, with a control of a delivery of here as a high-pressure pump 22 trained fuel pump and / or another actuator in a high-pressure circuit of the injection system 20 is adjusted.

In controlled emergency mode 56 an actual pressure, which is now determined indirectly via the measured injector flow on the basis of the correlation, is adapted to a provided target pressure, wherein an actual injector-correlated actual injector flow is correlated to a desired pressure correlated target injector flow is adjusted. It can about the metering unit 24 depending on the actual Injektorstroms a flow rate of the high-pressure pump 22 be adjusted.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008000983 A1 [0007]

Claims (11)

Method for operating an internal combustion engine of a motor vehicle, which via a fuel accumulator with a pressure sensor ( 30 ), whereby fuel from the fuel storage ( 26 ) Injectors ( 28 ), wherein a correlation between pressure values of a pressure of the fuel in the fuel reservoir ( 26 ) and current values of an injector stream of at least one injector ( 28 ) is adaptively learned to determine an adjustable injector current, wherein when set, there is a digital rich jump in the range of a critical pressure. The method of claim 1, wherein the correlation is learned during operation of the motor vehicle. Method according to Claim 1 or 2, in which the values for the pressure of fuel in the fuel reservoir ( 26 ) with the pressure sensor ( 30 ). Method according to one of claims 1 to 3, wherein the correlation is learned in a stationary load point of the internal combustion engine. Method according to one of claims 1 to 4, wherein for learning the injector flow is varied. Method according to one of Claims 1 to 4, in which the pressure is varied for learning. Method according to one of claims 1 to 6, wherein in the event that the pressure sensor ( 30 ), the adjustable injector flow is adjusted and an injection quantity is checked to see if the critical pressure is reached. Method for operating an internal combustion engine of a motor vehicle, which via a fuel storage ( 26 ) with a pressure sensor ( 30 ), whereby fuel from the fuel storage ( 26 ) Injectors ( 28 ), wherein an injector stream of at least one injector ( 28 ) is set, in which there is a digital jump in quantity in the range of a critical pressure. Method according to claim 8, which in case of failure of the pressure sensor ( 30 ) is carried out. The method of claim 8 or 9, wherein the digital quantity jump is detected based on a change in a rotational speed of the internal combustion engine. Arrangement for operating an internal combustion engine of a motor vehicle, which via a fuel storage ( 26 ) with a pressure sensor ( 30 in particular for performing a method according to one of claims 1 to 7, which is adapted to a correlation between pressure values of a pressure of the fuel in the fuel reservoir ( 26 ) and current values of an injector stream of at least one injector ( 28 ) adaptively to determine an adjustable injector current, wherein when set, there is a digital rich jump in the range of a critical pressure.

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