EP1178205B1 - Fuel supply system for internal combustion engine especially in a motor vehicle - Google Patents

Fuel supply system for internal combustion engine especially in a motor vehicle Download PDF

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Publication number
EP1178205B1
EP1178205B1 EP20010116806 EP01116806A EP1178205B1 EP 1178205 B1 EP1178205 B1 EP 1178205B1 EP 20010116806 EP20010116806 EP 20010116806 EP 01116806 A EP01116806 A EP 01116806A EP 1178205 B1 EP1178205 B1 EP 1178205B1
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EP
European Patent Office
Prior art keywords
pressure
fuel
pump
control valve
internal combustion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP20010116806
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German (de)
French (fr)
Other versions
EP1178205A2 (en
EP1178205A3 (en
Inventor
Klaus Joos
Jens Wolber
Thomas Frenz
Hansjoerg Bochum
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Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Filing date
Publication date
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Publication of EP1178205A2 publication Critical patent/EP1178205A2/en
Publication of EP1178205A3 publication Critical patent/EP1178205A3/en
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Publication of EP1178205B1 publication Critical patent/EP1178205B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F02D41/3845—Controlling the fuel pressure by controlling the flow into the common rail, e.g. the amount of fuel pumped
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/3082—Control of electrical fuel pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F02D41/3863—Controlling the fuel pressure by controlling the flow out of the common rail, e.g. using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D2041/389—Controlling fuel injection of the high pressure type for injecting directly into the cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/31—Control of the fuel pressure

Definitions

  • the invention relates to a method for operating a fuel supply system for an internal combustion engine, in particular of a motor vehicle, in which fuel is pumped by a pump into a pressure accumulator and injected by injection valves directly into the internal combustion engine. Furthermore, the invention relates to a fuel supply system for an internal combustion engine, in particular of a motor vehicle with a pressure accumulator and a pump, with the pressure accumulator fuel is supplied, and injectors with which fuel is injected directly into the internal combustion engine. Furthermore, the invention relates to a control device for an internal combustion engine, in particular of a motor vehicle, as well as a storage medium for a control unit of an internal combustion engine, in particular of a motor vehicle.
  • BDE gasoline direct injection
  • a method and a device for controlling an internal combustion engine with high-pressure injection, in particular for internal combustion engines with auto-ignition is known.
  • fuel is conveyed by a prefeed pump into a low-pressure region and conveyed by a high-pressure pump into a high-pressure region, a so-called common rail.
  • the prefeed pump conveys the fuel from a fuel tank, the tank, into a low pressure area and is designed as an electric fuel pump.
  • a pressure relief valve is arranged, which directs fuel from the low pressure region back into the tank of the motor vehicle when exceeding a certain pressure.
  • a pressure sensor is arranged, which detects the pressure in the common rail.
  • a pressure regulating valve is arranged between the high-pressure region and the tank of the motor vehicle, said pressure regulating valve being dependent on a driving current above a certain adjustable pressure Fuel from the high pressure area flows back into the tank. It is envisaged that the electric fuel pump is controlled in accordance with a drive signal in the speed to adjust the flow rate to the current needs of the engine. In case of system errors, the pressure control valve can be used as an emergency valve for quickly lowering the pressure in the common rail.
  • the DE 198 53 823 A1 discloses a method for operating an internal combustion engine, in particular a motor vehicle, in which the fuel from a first, usually driven by an electric motor fuel pump and by a second, usually mechanical high-pressure pump is fed into a pressure accumulator of the internal combustion engine.
  • the pumped amount of fuel is here by a corresponding influence of the electric motor driven first fuel pump changeable.
  • the pressure accumulator each required amount of fuel is supplied.
  • the delivery rate of the first fuel pump is controlled in dependence on the amount of fuel to be injected and / or the speed of the internal combustion engine and / or the temperature of the intake air and / or the battery voltage via a map.
  • the possibility is revealed of matching the characteristic map with each starting process of the internal combustion engine.
  • the actual value of the pressure in the accumulator is measured and compared with a desired value of the pressure in the pressure accumulator as a function of the required amount of fuel.
  • the characteristic map is adjusted.
  • the pressure in the pressure accumulator is detected by a pressure sensor arranged in the high-pressure circuit.
  • a pressure control valve which conveys excess fuel back into the tank of the motor vehicle.
  • the pressure control valve can be opened and closed via an input signal.
  • an electronic control device to which the output signal of the pressure sensor is connected and which generates the input signals for the first fuel pump and for the pressure control valve.
  • the fuel is injected by means of injection valves directly into the combustion chamber of the internal combustion engine.
  • a pressure sensor and a pressure control valve are also arranged. Both the electric high pressure pump and the pressure sensor, the injectors and the Pressure control valve are connected to a control unit, which carries out, inter alia, due to the data supplied by the pressure sensor at least the control of the electric high-pressure pump, the injection valves and the pressure control valve.
  • the possibility is disclosed to regulate the speed of the electric fuel pump according to the required delivery rate.
  • the control of the pressure control valve is carried out with different for each constant duty cycle, which are selected according to the operating condition, such as start or normal operation.
  • a high-pressure injection system is known in which the fuel pressure in the high pressure region is adjusted via an electrically operated fuel pump.
  • a so-called PID controller is provided which adjusts the speed and thus the delivery rate of the fuel pump in dependence on a predetermined desired fuel pressure.
  • gain factors of the PID control is intended to set gain factors of the PID control as a function of the demand demand.
  • a method for operating a fuel supply system for an internal combustion engine, in particular of a motor vehicle in which at least one first pump fuel is conveyed in a first pressure range, wherein at least one second, electrically operated pump, the fuel from the first pressure range in a second pressure range with at least a pressure accumulator is conveyed, in which injectors with the fuel from the second pressure range is injected directly into a combustion chamber, wherein the pressure in the second pressure range is detected with a pressure sensor, arranged at the pressure with a pressure control valve at the second pressure range is, the pressure in the second pressure range is controlled and in which a drive signal for the control of the pressure control valve is generated, compared to the prior art by the type of demand-driven control of the second pump in their speed further developed.
  • the advantage of the method according to the invention is that the demand-driven control of the second pump, with unrestricted function of the internal combustion engine, an energy saving of the entire system, so the motor vehicle is possible.
  • This is in particular because the electrically driven second pump, which is practically a high-pressure pump, has a very high energy requirement.
  • an amount of fuel required by the engine is determined and determines a target speed for the second pump at least from this fuel quantity required by the engine.
  • the pressure control means requires a certain overflow amount which flows back into the first pressure range via the pressure control means.
  • the target speed for the second pump must be such that at least the fuel required for the combustion in the combustion chambers of the engine and the fuel for the overflow of the pressure control means in the second pressure range is conveyed.
  • the target rotational speed determined in this way can be subjected to a safety and / or correction factor and / or with a safety and / or correction offset.
  • the first pump is controlled and / or regulated such that at least the fuel quantity required by the engine is conveyed into the first pressure range.
  • This control of the first pump according to the invention represents a pilot control, which additionally contributes to the energy saving of the overall system, that is to say the fuel consumption of the motor vehicle.
  • the drive signal for the control of the pressure control means is formed from the sum of two independent partial signals.
  • the first part signal is advantageously formed at least as a function of a pressure actual value and an operating point-dependent pressure target value in the second pressure range.
  • the second partial signal is advantageously determined at least as a function of inflowing and outflowing fuel mass into or out of the pressure accumulator, wherein the second partial signal is taken from an applicable map.
  • a development of the fuel supply system provides that the pressure control means and the second pump form a structural unit or that the pressure control means is integrated in the second pump.
  • the advantage of such a structural unit lies in the flexible arrangement of the unit within the engine compartment.
  • advantages in the layout in the engine compartment are advantages in the layout in the engine compartment.
  • a preferred development of the fuel supply system provides that the combustion chamber at least one ignition device is assigned, by means of which the fuel is ignitable in the combustion chamber. Also advantageous is a design of the internal combustion engine such that the fuel in the combustion chamber at least in a first mode during a compression phase and in a second mode during an intake phase is injectable.
  • the use of direct injection and the injection in the two different operating modes in combination with the fuel supply system according to the invention results in a particularly fuel-efficient, space-saving and cost-effective design of the internal combustion engine.
  • a program is stored on a storage medium for the control unit of the internal combustion engine, in particular a motor vehicle, the execution of the steps of the method for operating a fuel supply system for an internal combustion engine in particular of a motor vehicle on a computing device, in particular on a microprocessor in the control unit continuously.
  • the invention is thus realized by a program stored on the storage medium, so that this storage medium provided with the program represents the invention in the same way as the method which the program is suitable for executing.
  • an electrical storage medium may be used as the storage medium, for example a read-only memory (ROM) or an EPROM.
  • FIG. 1 shows a first embodiment of the device according to the invention.
  • a first pump 2 is arranged, which is usually designed as an electric fuel pump.
  • the electric fuel pump 2 is connected via a control line 4 to the engine control unit 3. Via the control line 4, the engine control unit, for example, influence the speed and thus take on the flow rate of the electric fuel pump 2.
  • the electric fuel pump 2 conveys the fuel from the tank 1 via a first pressure line 5 to a second pump 6.
  • the second pump 6, which is designed as an electrically driven high pressure pump, is connected via a control line 7 to the engine control unit 3.
  • the high-pressure electric pump 6 conveys the fuel via a second pressure line 8 into a pressure accumulator 9, a so-called common rail 9.
  • the high-pressure fuel passes via pressure lines 10 to injectors 11 (also called injectors) by means of of which the fuel is injected directly into a combustion chamber 12.
  • injectors 11 also called injectors
  • these are each connected via a control line 13 to the engine control unit 3.
  • a pressure sensor 14 is arranged in the second pressure range, which transmits a signal representing a pressure in the common rail 9 via the signal line 15 to the engine control unit 3.
  • a pressure-regulating and / or controlling means 16 is arranged in the region of the common rail 9.
  • the pressure regulating and / or controlling means 16 is designed as a pressure control valve.
  • the fuel flowing off from the pressure control valve 16 passes through a fuel line 18 back into the first pressure range 5, ie in the area in front of the second pump 6.
  • the pressure control valve 16 is connected via a control line 17 to the engine control unit 3. Via the control line 17, the engine control unit 3 can influence the parameters of the valve 16. This can be, for example, the setting of a predetermined pressure level in the common rail 9, beyond which the overpressure which would arise in the common rail is reduced by the fact that the fuel via the pressure control valve 16 flows back into the first pressure range (overflow).
  • the core of the fuel supply system according to the invention is a speed control device 19 for controlling the electric high-pressure pump 6.
  • the speed control device 19 is connected to a control line 20 to the engine control unit 3.
  • a corresponding control of the electric high-pressure pump 6 is made via line 21.
  • the electrically driven high-pressure pump 6 may be, for example, an asynchronous electric motor which is coupled to a mechanical pump. It is also within the scope of the fuel supply system according to the invention that the high-pressure pump unit 6 is arranged structurally separate from the engine block 23 enclosing the combustion chamber. By this arrangement, there are thermal advantages, especially in hot start situations and advantages in terms of the flexibility in installing the system in an engine compartment of a motor vehicle (better packaging possible).
  • a quantity control valve which can be controlled via the control line 7, which connects the engine control unit 3 to the high-pressure pump unit 6. By using a quantity control valve within the high-pressure pump unit 6, it is possible, via a drive signal, to set the amount of fuel supplied to the high-pressure pump unit 6.
  • the controller referred to in the previous versions as the engine control unit 3 can of course be a special controller in the general case, which has only the control of the components of the fuel supply system as a task.
  • the control unit 3 can also be combined together with the speed control device 19 and the high pressure pump 6 to form a single structural unit.
  • the combination of these components into a single control, regulation and pump unit offers particular advantages in packaging in the engine compartment and brings the advantage for the motor vehicle manufacturer to equip an existing engine concept particularly easy and flexible with a new high-pressure fuel supply system.
  • control unit 3 is the central engine control unit of the motor vehicle
  • various other signal lines 22 are indicated which serve to perceive the further functions of the engine control unit 3.
  • control unit 3 is according to the invention, a storage medium on which a program is stored, that the execution of the previously described function as well as the function of the method according to the invention in the further in the context of FIGS. 3 to 5 is explained in more detail, allows.
  • each combustion chamber is assigned at least one spark plug, by means of which the fuel in the combustion chamber 12 can be ignited.
  • the spark plugs, of which at least one per combustion chamber / cylinder 12 of the internal combustion engine is arranged, are shown in the illustration FIG. 1 (and also FIG. 2 ) Not shown.
  • Such systems offer the possibility of injecting the fuel at least in a first operating mode during a compression phase and in a second operating mode during an intake phase.
  • the second mode of operation during which it is injected into the intake phase of the respective combustion chamber 12, corresponds approximately to the homogeneous air-gas mixture which enters the combustion chamber in the context of conventional (non-direct) injection.
  • the first mode during which it is injected into the compression phase of the combustion chamber is also referred to as stratified charge or stratified charge.
  • the shift operation is particularly suitable when no high power requirements are placed on the internal combustion engine. In this case, the internal combustion engine usually has a lower fuel requirement than in homogeneous operation.
  • the fuel supply system according to the invention is particularly well suited during the shift operation to supply the internal combustion engine on demand with the necessary fuel. This means that, in particular during the shift operation, both the rotational speed of the prefeed pump 2 and the rotational speed of the high-pressure pump 6 can be reduced, which leads to a significantly reduced energy requirement of the pumps 2 and / or 6. Another advantage is that during operation with reduced speed of the pumps 2 and / or 6, the load for the respective pump is not as high as at maximum speed and thus can be assumed to have a longer life of the pump 2 and / or 6 , The integrated in the high pressure pump 6 quantity control valve is also controlled accordingly reduced.
  • FIG. 2 shows a second embodiment of the device according to the invention, in which the same elements are identified by the identical reference numerals.
  • the pressure control valve 16 ' which is integrated in this second embodiment in the high-pressure pump unit 6 and is attached to the high-pressure pump unit 6.
  • the excess fuel can flow via the line 18' back into the first pressure range 5 in front of the high-pressure pump 6.
  • the control of the pressure control valve 16 ' via a control line 17', which connects the pressure control valve 16 'with the engine control unit 3.
  • the advantage of the integration of the pressure control valve 16 'in the high pressure pump unit 6 is that this creates a high pressure pump module that can be flexibly integrated into existing concepts of internal combustion engines. In other words, it is made easier for a motor vehicle manufacturer to convert an existing internal combustion engine to an internal combustion engine with high-pressure injection.
  • FIG. 3 shows an embodiment of the method according to the invention, wherein in FIG. 3 specifically the control of the pressure control valve 16 or 16 'is shown.
  • two partial signals 31 and 32 are formed in two determination units, which are summed up in a block 33 to form a total signal.
  • the input signals / input data required for the determination of the two partial signals from the determination units 31 and 32 are supplied by the engine control unit 3 directly or indirectly. Indirect here means that the data is not made available for example via a direct connection between the engine control unit 3 and the determination units 31 and 32, but that the transmission of data via a vehicle-bus system (CAN bus) takes place.
  • CAN bus vehicle-bus system
  • a partial signal is generated, which can be referred to as a control component, while in the determination unit 32, a partial signal is generated, which can be referred to as a pilot proportion.
  • the control component in the determination unit 31 is formed in dependence on the prevailing in the common rail 9 pressure-actual value and an operating point-dependent pressure-target value in the common rail 9.
  • the pressure-actual value of the common rail 9 is as in FIG. 1 explained with the pressure sensor 14 detected and passes through the control unit 3 to the determination unit 31.
  • the operating point-dependent pressure-target value in the common rail 9 can be taken, for example, an administered in the control unit 3 applicable map.
  • the pilot proportion, which is formed in the determination unit 32, is determined at least as a function of inflowing and outflowing fuel mass into and out of the pressure accumulator. The concrete determination of the inflowing or outflowing quantities of fuel into or out of the common rail 9 will be discussed in detail in the description FIG. 3 explained.
  • the composite signal is converted in step 34 into a corresponding control signal for the pressure control valve 16 or 16 '.
  • the resulting drive signal which is formed in step 34, may be, for example, a duty cycle, a pulse width modulation or, if a quantity control valve is used, for example an angle control between 0 and 180 °.
  • FIG. 4 shows the formation of the first partial signal for controlling the pressure control valve 16 or 16 ', in detail.
  • steps 41 and 42 represent the actual value detection of the pressure in the common rail 9, while the process step 44 symbolizes the target value formation of the pressure in the common rail 9.
  • step 43 the target actual control difference is formed from the difference between the setpoint and actual value of the pressure in the common rail 9.
  • step 45 the control difference, which has been determined in step 43, is converted with a PI controller or a PID controller into the corresponding first partial signal for controlling the pressure control valve 16 or 16 'and corresponding to the method step 33 FIG. 3 to hand over.
  • step 41 the pressure-characterizing signal of the pressure sensor 14 is thus detected and forwarded to the step 42 for filtering.
  • step 42 for example, a low-pass filtering takes place in order to filter out high-frequency interference from the pressure signal.
  • the result of step 42 is the actual signal of the pressure in the common rail 9, which is forwarded to step 43.
  • step 44 of the method according to the invention a desired value for the pressure in the common rail 9 is taken / formed in accordance with the current operating data from an operating point-dependent characteristic field, which is stored in the control unit 3, and transmitted to step 43.
  • step 32 after FIG. 3 was the pilot component for controlling the pressure control valve 16 and 16 ', inter alia, based on the inflowing or outflowing amount of fuel in or out of the common rail 9 determined.
  • the determination of the quantity balance required for this purpose is described below in the context of FIG. 5 explained.
  • step 51 the amount of fuel flowing to the common rail 9 is determined. This amount of fuel is proportional to the product of efficiency of the electric high-pressure pump 6, speed of the electric high-pressure pump 6 and duty cycle of the integrated in the high-pressure pump 6 quantity control valve (or an equivalent drive signal for the quantity control valve).
  • step 53 the fuel quantity is determined, which is injected via the injectors 11 into the combustion chambers of the internal combustion engine. This amount of fuel is proportional to the product of the determined in the engine control unit 3 amount of fuel per injection and the speed of the internal combustion engine.
  • step 55 the fuel quantity is determined, which flows via the pressure control valve 16 or 16 'back into the first pressure range in front of the electric high-pressure pump 6.
  • the corresponding overflowing amount of fuel of the pressure control valve is taken from an applicable map in the engine control unit 3 at least as a function of the drive signal or the duty cycle of the pressure control valve and the currently prevailing pressure in the common rail 9.
  • step 53 the fuel quantity determined in step 53 and fed to the common rail 9 in step 51 will be subtracted from the fuel mass determined in step 53 and discharged through the injection into the combustion chambers from the common rail 9.
  • step 54 The output signal of method step 52 is transmitted to a further differential element in step 54, in which, in addition, the overflow quantity of pressure control valve 16 or 16 'determined in step 55 is subtracted.
  • the result of method step 54 is the quantity of fuel effectively flowing in to the common rail 9, in practice thus the increase in the fuel quantity in the common rail 9.
  • Another possibility to improve the control for the fuel supply system in the context of the method according to the invention is that the speed of the high pressure pump 6 is taken into account in the feedforward control of the electric fuel pump 2.
  • an applicable map can be stored in the control unit 3, which determines a correction factor and / or a correction offset for the drive signal (for speed control) of the electric fuel pump in dependence on the specific target speed of the high-pressure pump 6.

Description

Stand der TechnikState of the art

Die Erfindung betrifft ein Verfahren zum Betreiben eines Kraftstoffversorgungssystems für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs, bei dem Kraftstoff von einer Pumpe in einen Druckspeicher gepumpt und von Einspritzventilen direkt in die Brennkraftmaschine eingespritzt wird. Des Weiteren betrifft die Erfindung ein Kraftstoffversorgungssystem für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs mit einem Druckspeicher und einer Pumpe, mit der dem Druckspeicher Kraftstoff zuführbar ist, und mit Einspritzventilen, mit denen Kraftstoff direkt in die Brennkraftmaschine einspritzbar ist. Weiterhin betrifft die Erfindung ein Steuergerät für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs sowie ein Speichermedium für ein Steuergerät einer Brennkraftmaschine insbesondere eines Kraftfahrzeugs.The invention relates to a method for operating a fuel supply system for an internal combustion engine, in particular of a motor vehicle, in which fuel is pumped by a pump into a pressure accumulator and injected by injection valves directly into the internal combustion engine. Furthermore, the invention relates to a fuel supply system for an internal combustion engine, in particular of a motor vehicle with a pressure accumulator and a pump, with the pressure accumulator fuel is supplied, and injectors with which fuel is injected directly into the internal combustion engine. Furthermore, the invention relates to a control device for an internal combustion engine, in particular of a motor vehicle, as well as a storage medium for a control unit of an internal combustion engine, in particular of a motor vehicle.

An eine Brennkraftmaschine beispielsweise eines Kraftfahrzeugs werden immer höhere Anforderungen im Hinblick auf eine Reduzierung des Kraftstoffverbrauchs und der erzeugten Abgase bei einer gleichzeitig erwünschten erhöhten Leistung gestellt. Zu diesem Zweck sind moderne Brennkraftmaschinen mit einem Kraftstoffversorgungssystem versehen bei dem die Zuführung von Kraftstoff in den Brennraum der Brennkraftmaschine elektronisch, insbesondere mit einem rechnergestützten Steuergerät, gesteuert und/oder geregelt wird.To an internal combustion engine, for example, a motor vehicle ever higher demands are made in terms of reducing the fuel consumption and the exhaust gases produced at the same time desired increased Power provided. For this purpose, modern internal combustion engines are provided with a fuel supply system in which the supply of fuel in the combustion chamber of the internal combustion engine electronically, in particular with a computer-aided control device, controlled and / or regulated.

Bei der sogenannten Benzindirekteinspritzung (BDE) ist es erforderlich, dass der Kraftstoff unter Druck in den Brennraum eingespritzt wird. Zu diesem Zweck ist ein Druckspeicher vorgesehen, in den der Kraftstoff mittels einer Pumpe gepumpt und unter einen hohen Druck gesetzt wird. Von dort wird der Kraftstoff dann über Einspritzventile direkt in die Brennräume der Brennkraftmaschine eingespritzt.In the so-called gasoline direct injection (BDE), it is necessary that the fuel is injected under pressure into the combustion chamber. For this purpose, an accumulator is provided, in which the fuel is pumped by means of a pump and placed under a high pressure. From there, the fuel is then injected via injection valves directly into the combustion chambers of the internal combustion engine.

Aus der DE 195 48 278 A1 ist ein Verfahren und eine Vorrichtung zur Steuerung einer Brennkraftmaschine mit Hochdruckeinspritzung insbesondere für Brennkraftmaschinen mit Selbstzündung bekannt. Hierbei wird von einer Vorförderpumpe Kraftstoff in einen Niederdruckbereich befördert und von einer Hochdruckpumpe in einen Hochdruckbereich, einem sogenannten Common-Rail, befördert. Die Vorförderpumpe befördert den Kraftstoff aus einem Kraftstoffvorratsbehälter, dem Tank, in einen Niederdruckbereich und ist als Elektrokraftstoffpumpe ausgeführt. Parallel zur Elektrokraftstoffpumpe ist ein Druckbegrenzungsventil angeordnet, das bei Überschreitung eines bestimmten Druckes Kraftstoff aus dem Niederdruckbereich zurück in den Tank des Kraftfahrzeugs leitet. Im Hochdruckbereich ist ein Drucksensor angeordnet, der den Druck im Common-Rail erfasst. Weiterhin ist zwischen dem Hochdruckbereich und dem Tank des Kraftfahrzeugs ein Druckregelventil angeordnet, welches in Abhängigkeit von einem Ansteuerstrom ab einem bestimmten einstellbaren Druck Kraftstoff aus dem Hochdruckbereich zurück in den Tank leitet. Es ist vorgesehen, dass die Elektrokraftstoffpumpe entsprechend eines Ansteuersignals in der Drehzahl geregelt wird, um die Fördermenge an den aktuellen Bedarf des Motors anzupassen. Bei Systemfehlern kann das Druckregelventil als Notventil zum schnellen Absenken des Druckes im Common-Rail verwendet werden.From the DE 195 48 278 A1 a method and a device for controlling an internal combustion engine with high-pressure injection, in particular for internal combustion engines with auto-ignition is known. In this case, fuel is conveyed by a prefeed pump into a low-pressure region and conveyed by a high-pressure pump into a high-pressure region, a so-called common rail. The prefeed pump conveys the fuel from a fuel tank, the tank, into a low pressure area and is designed as an electric fuel pump. Parallel to the electric fuel pump, a pressure relief valve is arranged, which directs fuel from the low pressure region back into the tank of the motor vehicle when exceeding a certain pressure. In the high pressure area, a pressure sensor is arranged, which detects the pressure in the common rail. Furthermore, a pressure regulating valve is arranged between the high-pressure region and the tank of the motor vehicle, said pressure regulating valve being dependent on a driving current above a certain adjustable pressure Fuel from the high pressure area flows back into the tank. It is envisaged that the electric fuel pump is controlled in accordance with a drive signal in the speed to adjust the flow rate to the current needs of the engine. In case of system errors, the pressure control valve can be used as an emergency valve for quickly lowering the pressure in the common rail.

Die DE 198 53 823 A1 offenbart ein Verfahren zum Betreiben einer Brennkraftmaschine insbesondere eines Kraftfahrzeugs, bei dem der Kraftstoff von einer ersten, üblicherweise elektromotorisch angetriebenen Kraftstoffpumpe und von einer zweiten, üblicherweise mechanischen Hochdruckpumpe in einen Druckspeicher der Brennkraftmaschine gefördert wird. Die geförderte Kraftstoffmenge ist hierbei durch eine entsprechende Beeinflussung der elektromotorisch angetriebenen ersten Kraftstoffpumpe veränderbar. Auf diese Weise wird dem Druckspeicher die jeweils erforderliche Kraftstoffmenge zugeführt. Die Fördermenge der ersten Kraftstoffpumpe wird in Abhängigkeit von der einzuspritzenden Kraftstoffmenge und/oder der Drehzahl der Brennkraftmaschine und/oder der Temperatur der angesaugten Luft und/oder der Batteriespannung über ein Kennfeld gesteuert. Um Toleranzen der verschiedenen Kraftstoffpumpen wie auch altersbedingte Veränderungen abzugleichen, wird die Möglichkeit offenbart, das Kennfeld bei jedem Startvorgang der Brennkraftmaschine abzugleichen. Zum Abgleich wird beispielsweise der Ist-Wert des Drucks im Druckspeicher gemessen und mit einem Soll-Wert des Drucks in dem Druckspeicher in Abhängigkeit von der erforderlichen Kraftstoffmenge verglichen. In Abhängigkeit des Vergleichs des bestimmten Ist-Wertes und des Soll-Wertes des Drucks im Druckspeicher wird das Kennfeld abgeglichen. Der Druck im Druckspeicher wird mit einem im Hochdruckkreis angeordneten Drucksensor erfasst. Zur Steuerung des Drucks im Hochdruckspeicher ist im Hochdruckspeicher ein Drucksteuerventil angeordnet, das überschüssigen Kraftstoff zurück in den Tank des Kraftfahrzeugs befördert. Das Drucksteuerventil kann über ein Eingangssignal geöffnet und geschlossen werden. Es ist weiterhin ein elektronisches Steuergerät vorgesehen, an das das Ausgangssignal des Drucksensors angeschlossen ist und das die Eingangssignale für die erste Kraftstoffpumpe und für das Drucksteuerventil erzeugt. Durch diese Maßnahme kann von dem elektronischen Steuergerät Einfluss auf die Fördermenge der ersten Kraftstoffpumpe sowie auf den Druck im Hochdruckbereich durch das Drucksteuerventil genommen werden.The DE 198 53 823 A1 discloses a method for operating an internal combustion engine, in particular a motor vehicle, in which the fuel from a first, usually driven by an electric motor fuel pump and by a second, usually mechanical high-pressure pump is fed into a pressure accumulator of the internal combustion engine. The pumped amount of fuel is here by a corresponding influence of the electric motor driven first fuel pump changeable. In this way, the pressure accumulator each required amount of fuel is supplied. The delivery rate of the first fuel pump is controlled in dependence on the amount of fuel to be injected and / or the speed of the internal combustion engine and / or the temperature of the intake air and / or the battery voltage via a map. In order to balance tolerances of the various fuel pumps as well as age-related changes, the possibility is revealed of matching the characteristic map with each starting process of the internal combustion engine. For comparison, for example, the actual value of the pressure in the accumulator is measured and compared with a desired value of the pressure in the pressure accumulator as a function of the required amount of fuel. Depending on the comparison of the determined actual value and the desired value of the pressure in the accumulator, the characteristic map is adjusted. The pressure in the pressure accumulator is detected by a pressure sensor arranged in the high-pressure circuit. To control the pressure in the High-pressure accumulator is arranged in the high-pressure accumulator, a pressure control valve, which conveys excess fuel back into the tank of the motor vehicle. The pressure control valve can be opened and closed via an input signal. There is further provided an electronic control device to which the output signal of the pressure sensor is connected and which generates the input signals for the first fuel pump and for the pressure control valve. By this measure can be taken by the electronic control unit influence on the flow rate of the first fuel pump and the pressure in the high pressure region by the pressure control valve.

Aus der noch nicht vorveröffentlichten deutschen Patentanmeldung DE 199 03 272.6-13 ist ein Kraftstoffversorgungssystem für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs bekannt, bei dem Kraftstoff mittels einer Pumpe in einen Druckspeicher gepumpt und von Einspritzventilen direkt in die Brennkraftmaschine eingespritzt wird. Es werden die Möglichkeiten offenbart, die Pumpe mechanisch, also durch starre Kopplung an die Brennkraftmaschine, anzutreiben oder die Pumpe als eine elektrische Pumpe auszuführen. Das Gesamtsystem entsprechend der noch nicht vorveröffentlichten deutschen Patentanmeldung DE 199 03 272.6-13 weist eine Elektrokraftstoffpumpe auf, die Kraftstoff aus einem Tank in einen Niederdruckbereich befördert. Von diesem Niederdruckbereich ausgehend wird der Kraftstoff mittels der Hochdruckpumpe in einen Druckbereich bzw. ein Common-Rail befördert. Von diesem Druckbereich ausgehend wird der Kraftstoff mittels Einspritzventilen direkt in den Brennraum der Brennkraftmaschine eingespritzt. Im Hochdruckbereich des Systems sind zudem ein Drucksensor und ein Drucksteuerventil angeordnet. Sowohl die elektrische Hochdruckpumpe als auch der Drucksensor, die Einspritzventile und das Drucksteuerventil sind mit einem Steuergerät verbunden, das u. a. aufgrund der von dem Drucksensor gelieferten Daten wenigstens die Ansteuerung der elektrischen Hochdruckpumpe, der Einspritzventile und des Drucksteuerventils vornimmt. Zur Steuerung der geförderten Kraftstoffmenge wird die Möglichkeit offenbart, die Drehzahl der Elektrokraftstoffpumpe entsprechend der benötigten Förderleistung zu regeln. Die Ansteuerung des Drucksteuerventils erfolgt mit unterschiedlichen für sich jeweils konstanten Taktverhältnissen, die entsprechend des Betriebszustandes, beispielsweise Start- oder Normalbetrieb ausgewählt werden. Die Besonderheit der noch nicht vorveröffentlichten deutschen Patentanmeldung DE 199 03 272.6-13 ist darin zu sehen, dass die Hochdruckpumpe derart ausgebildet und dimensioniert ist, dass innerhalb einer geringen Zeitdauer, speziell innerhalb von wenigen Umdrehungen der Brennkraftmaschine bereits der für die Einspritzung von Kraftstoff in die Brennräume der Brennkraftmaschine ausreichende Druck in dem Druckspeicher vorhanden ist.From the not yet published German patent application DE 199 03 272.6-13 a fuel supply system for an internal combustion engine, in particular of a motor vehicle is known in which fuel is pumped by a pump in a pressure accumulator and injected by injectors directly into the internal combustion engine. The possibilities are disclosed of driving the pump mechanically, that is to say by rigid coupling to the internal combustion engine, or of carrying out the pump as an electric pump. The entire system according to the not yet published German patent application DE 199 03 272.6-13 has an electric fuel pump that conveys fuel from a tank to a low pressure area. Starting from this low-pressure region, the fuel is conveyed by means of the high-pressure pump into a pressure region or a common rail. Starting from this pressure range, the fuel is injected by means of injection valves directly into the combustion chamber of the internal combustion engine. In the high pressure region of the system, a pressure sensor and a pressure control valve are also arranged. Both the electric high pressure pump and the pressure sensor, the injectors and the Pressure control valve are connected to a control unit, which carries out, inter alia, due to the data supplied by the pressure sensor at least the control of the electric high-pressure pump, the injection valves and the pressure control valve. To control the amount of fuel delivered, the possibility is disclosed to regulate the speed of the electric fuel pump according to the required delivery rate. The control of the pressure control valve is carried out with different for each constant duty cycle, which are selected according to the operating condition, such as start or normal operation. The peculiarity of the not yet published German patent application DE 199 03 272.6-13 is to be seen in that the high pressure pump is designed and dimensioned such that within a short period of time, especially within a few revolutions of the internal combustion engine already sufficient for the injection of fuel into the combustion chambers of the internal combustion engine pressure in the pressure accumulator is present.

Aus der EP 0 725 212 A2 ist ein Hochdruckeinspritzsystem bekannt, bei dem der Kraftstoffdruck im Hochdruckbereich über eine elektrisch betriebene Kraftstoffpumpe eingestellt wird. Zur Regelung des Kraftstoffdrucks ist ein so genannter PID-Regler vorgesehen, der die Drehzahl und somit die Förderleistung der Kraftstoffpumpe in Abhängigkeit eines vorgegebenen gewünschten Kraftstoffdrucks einstellt. Um Regelschwankungen aufgrund wechselnder Kraftstoffanforderungen zu vermeiden, ist es vorgesehen, Verstärkungsfaktoren der PID-Regelung in Abhängigkeit der Bedarfsanforderung einzustellen.From the EP 0 725 212 A2 a high-pressure injection system is known in which the fuel pressure in the high pressure region is adjusted via an electrically operated fuel pump. To regulate the fuel pressure, a so-called PID controller is provided which adjusts the speed and thus the delivery rate of the fuel pump in dependence on a predetermined desired fuel pressure. In order to avoid control fluctuations due to changing fuel requirements, it is intended to set gain factors of the PID control as a function of the demand demand.

Vorteile der ErfindungAdvantages of the invention

Ein Verfahren zum Betrieb eines Kraftstoffversorgungssystems für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs, bei dem mit wenigstens einer ersten Pumpe Kraftstoff in einen ersten Druckbereich befördert wird, bei dem mit wenigstens einer zweiten, elektrisch betriebenen Pumpe der Kraftstoff aus dem ersten Druckbereich in einen zweiten Druckbereich mit wenigstens einem Druckspeicher befördert wird, bei dem mit Einspritzventilen der Kraftstoff aus dem zweiten Druckbereich direkt in einen Brennraum eingespritzt wird, bei dem mit einem Drucksensor der Druck im zweiten Druckbereich erfasst wird, bei dem mit einem Drucksteuerventils das am zweiten Druckbereich angeordnet ist, der Druck im zweiten Druckbereich geregelt wird und bei dem ein Ansteuersignal für die Ansteuerung des Drucksteuerventils generiert wird, ist gegenüber dem Stand der Technik durch die Art der bedarfsgerechten Ansteuerung der zweiten Pumpe in ihrer Drehzahl weitergebildet. Der Vorteil des erfindungsgemäßen Verfahrens liegt darin, dass durch die bedarfsgerechte Ansteuerung der zweiten Pumpe, bei uneingeschränkter Funktion der Brennkraftmaschine, eine Energieeinsparung des Gesamtsystems, also des Kraftfahrzeugs, möglich ist. Dies liegt insbesondere daran, dass die elektrisch angetriebene zweite Pumpe, die praktisch eine Hochdruckpumpe darstellt, einen sehr hohen Energiebedarf hat.A method for operating a fuel supply system for an internal combustion engine, in particular of a motor vehicle, in which at least one first pump fuel is conveyed in a first pressure range, wherein at least one second, electrically operated pump, the fuel from the first pressure range in a second pressure range with at least a pressure accumulator is conveyed, in which injectors with the fuel from the second pressure range is injected directly into a combustion chamber, wherein the pressure in the second pressure range is detected with a pressure sensor, arranged at the pressure with a pressure control valve at the second pressure range is, the pressure in the second pressure range is controlled and in which a drive signal for the control of the pressure control valve is generated, compared to the prior art by the type of demand-driven control of the second pump in their speed further developed. The advantage of the method according to the invention is that the demand-driven control of the second pump, with unrestricted function of the internal combustion engine, an energy saving of the entire system, so the motor vehicle is possible. This is in particular because the electrically driven second pump, which is practically a high-pressure pump, has a very high energy requirement.

Beim erfindungsgemäßen Verfahren wird eine vom Motor benötigte Kraftstoffmenge bestimmt und wenigstens aus dieser vom Motor benötigten Kraftstoffmenge eine Soll-Drehzahl für die zweite Pumpe bestimmt. Zusätzlich muss bei der Ansteuerung der zweiten Pumpe mit einer bestimmten Soll-Drehzahl berücksichtigt werden, dass das Druckregelmittel in der Praxis eine bestimmte Überströmmenge benötigt, die über das Druckregelmittel zurück in den ersten Druckbereich abfließt. Mit anderen Worten: Die Soll-Drehzahl für die zweite Pumpe muss so bemessen werden, dass wenigstens der für die Verbrennung in den Brennräumen der Kraftmaschine erforderliche Kraftstoff sowie der Kraftstoff für die Überströmung des Druckregelmittels im zweiten Druckbereich gefördert wird. Praktisch kann die auf diese Weise bestimmte Soll-Drehzahl mit einem Sicherheits- und/oder Korrekturfaktor und/oder mit einem Sicherheits- und/oder Korrektur-Offset beaufschlagt werden.In the method according to the invention, an amount of fuel required by the engine is determined and determines a target speed for the second pump at least from this fuel quantity required by the engine. In addition, when controlling the second pump with a certain setpoint speed, it must be taken into account that in practice the pressure control means requires a certain overflow amount which flows back into the first pressure range via the pressure control means. In other words, the target speed for the second pump must be such that at least the fuel required for the combustion in the combustion chambers of the engine and the fuel for the overflow of the pressure control means in the second pressure range is conveyed. In practice, the target rotational speed determined in this way can be subjected to a safety and / or correction factor and / or with a safety and / or correction offset.

Eine vorteilhafte Weiterbildung des erfindungsgemäßen Verfahren sieht vor, dass die erste Pumpe derart angesteuert und/oder geregelt wird, dass wenigstens die vom Motor benötigte Kraftstoffmenge in den ersten Druckbereich befördert wird. Diese erfindungsgemäße Ansteuerung der ersten Pumpe stellt eine Vorsteuerung dar, die zusätzlich zur Energieeinsparung des Gesamtsystems, also des Kraftstoffverbrauchs des Kraftfahrzeuges beiträgt.An advantageous development of the method according to the invention provides that the first pump is controlled and / or regulated such that at least the fuel quantity required by the engine is conveyed into the first pressure range. This control of the first pump according to the invention represents a pilot control, which additionally contributes to the energy saving of the overall system, that is to say the fuel consumption of the motor vehicle.

Die bevorzugte Weiterbildung des erfindungsgemäßen Verfahren sieht vor, dass das Ansteuersignal für die Ansteuerung des Druckregelmittels aus der Summe zweier unabhängiger Teilsignale gebildet wird. Hierbei wird vorteilhafter Weise das erste Teilsignal wenigstens in Abhängigkeit von einem Druck-Ist-Wert und einem betriebspunktabhängigen Druck-Soll-Wert im zweiten Druckbereich gebildet. Das zweite Teilsignal wird vorteilhafter Weise wenigstens in Abhängigkeit von zuströmender und abströmender Kraftstoffmasse in bzw. aus dem Druckspeicher bestimmt, wobei das zweite Teilsignal aus einem applizierbaren Kennfeld entnommen wird. Durch die erfindungsgemäße Bestimmung des Ansteuersignals für die Ansteuerung des Druckregelmittels aus einem ersten Teilsignal, das einen Regelanteil repräsentiert, und einem zweiten Teilsignal, das einen Vorsteueranteil repräsentiert, wird in besonders vorteilhafter Weise der Druck im Druckspeicher so geregelt, dass in jeder Betriebssituation der erforderliche Druck für die Einspritzung zur Verfügung steht.The preferred development of the method according to the invention provides that the drive signal for the control of the pressure control means is formed from the sum of two independent partial signals. In this case, the first part signal is advantageously formed at least as a function of a pressure actual value and an operating point-dependent pressure target value in the second pressure range. The second partial signal is advantageously determined at least as a function of inflowing and outflowing fuel mass into or out of the pressure accumulator, wherein the second partial signal is taken from an applicable map. The inventive determination of the drive signal for the control of the pressure control means from a first partial signal representing a control component, and a second partial signal representing a pilot component, the pressure in the pressure accumulator is controlled in a particularly advantageous manner so that in each operating situation, the required pressure is available for injection.

Ein Kraftstoffversorgungssystem für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs mit wenigstens einer ersten Pumpe, mittels der Kraftstoff in einen ersten Druckbereich beförderbar ist, mit wenigstens einer zweiten, elektrisch betriebenen Pumpe, mittels der der Kraftstoff aus dem ersten Druckbereich in einen zweiten Druckbereich mit wenigstens einem Druckspeicher beförderbar ist, mit Einspritzventilen, mittels derer der Kraftstoff aus dem zweiten Druckbereich direkt in einen Brennraum einspritzbar ist, mit einem Drucksensor, mittels dem der Druck im zweiten Druckbereich erfasst wird, mit einem Druckregelmittel, das im zweiten Druckbereich angeordnet ist, mittels dem der Druck im zweiten Druckbereich regelbar ist und mit Mitteln zur Generierung eines Ansteuersignals für das Druckregelmittel, ist gegenüber dem Stand der Technik dadurch weitergebildet, dass Mittel vorhanden sind, mittels derer die zweite Pumpe in ihrer Drehzahl ansteuerbar und/oder regelbar ist.A fuel supply system for an internal combustion engine, in particular of a motor vehicle, having at least one first pump, by means of which fuel is conveyed into a first pressure range, with at least one second, electrically operated pump, by means of which the fuel from the first pressure range in a second pressure range at least one pressure accumulator is conveyed, with injection valves, by means of which the fuel from the second pressure range can be injected directly into a combustion chamber, with a pressure sensor, by means of which the pressure in the second pressure range is detected, with a pressure control means, which is arranged in the second pressure range by means of the pressure in the second pressure range is controllable and with means for generating a drive signal for the pressure control means is further developed over the prior art in that means are provided by means of which the second pump can be controlled in its speed and / or regulated.

Die Vorteile des erfindungsgemäßen Kraftstoffversorgungssystems liegen, wie schon zuvor beim erfindungsgemäßen Verfahren in der Energieeinsparung des Gesamtsystems bei gleichzeitig vorhandener Versorgungssicherheit und Druckstabilität im zweiten Druckbereich.The advantages of the fuel supply system according to the invention lie, as previously in the method according to the invention, in the energy saving of the overall system with simultaneously available security of supply and pressure stability in the second pressure range.

Eine Weiterbildung des Kraftstoffversorgungssystems sieht vor, dass das Druckregelmittel und die zweite Pumpe eine bauliche Einheit bilden bzw. dass das Druckregelmittel in die zweite Pumpe integriert ist. Der Vorteil einer solchen baulichen Einheit liegt in der flexiblen Anordnung der Einheit innerhalb des Motorraums. Hier ergeben sich Vorteile bei der Raumaufteilung im Motorraum.A development of the fuel supply system provides that the pressure control means and the second pump form a structural unit or that the pressure control means is integrated in the second pump. The advantage of such a structural unit lies in the flexible arrangement of the unit within the engine compartment. Here are advantages in the layout in the engine compartment.

Eine bevorzugte Weiterbildung des Kraftstoffversorgungssystems sieht vor, dass dem Brennraum wenigstens eine Zündvorrichtung zugeordnet ist, mittels derer der Kraftstoff in dem Brennraum entzündbar ist. Weiterhin vorteilhaft ist eine Auslegung der Brennkraftmaschine derart, dass der Kraftstoff in dem Brennraum wenigstens in einer ersten Betriebsart während einer Verdichtungsphase und in einer zweiten Betriebsart während einer Ansaugphase einspritzbar ist. Insbesondere die Verwendung der direkten Einspritzung und die Einspritzung in den zwei unterschiedlichen Betriebsarten in Kombination mit dem erfindungsgemäßen Kraftstoffversorgungssystem ergibt eine besonders kraftstoffsparende, platzsparende und kostengünstige Auslegung der Brennkraftmaschine.A preferred development of the fuel supply system provides that the combustion chamber at least one ignition device is assigned, by means of which the fuel is ignitable in the combustion chamber. Also advantageous is a design of the internal combustion engine such that the fuel in the combustion chamber at least in a first mode during a compression phase and in a second mode during an intake phase is injectable. In particular, the use of direct injection and the injection in the two different operating modes in combination with the fuel supply system according to the invention results in a particularly fuel-efficient, space-saving and cost-effective design of the internal combustion engine.

Von besonderer Bedeutung ist die Realisierung des erfindungsgemäßen Verfahrens in der Form eines Steuergeräts für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs. Dabei ist auf einem Speichermedium für das Steuergerät der Brennkraftmaschine insbesondere eines Kraftfahrzeugs ein Programm abgespeichert, das auf einem Rechengerät, insbesondere auf einem Mikroprozessor im Steuergerät laufend die Ausführung der Schritte des Verfahrens zum Betrieb eines Kraftstoffversorgungssystems für eine Brennkraftmaschine insbesondere eines Kraftfahrzeugs bewirkt. In diesem Fall wird also die Erfindung durch ein auf dem Speichermedium abgespeichertes Programm realisiert, so dass dieses mit dem Programm versehene Speichermedium in gleicher Weise die Erfindung darstellt, wie das Verfahren, zu dessen Ausführung das Programm geeignet ist. Als Speichermedium kann insbesondere ein elektrisches Speichermedium zur Anwendung kommen, beispielsweise ein Read-Only-Memory (ROM) oder ein EPROM.Of particular importance is the realization of the method according to the invention in the form of a control device for an internal combustion engine, in particular of a motor vehicle. In this case, a program is stored on a storage medium for the control unit of the internal combustion engine, in particular a motor vehicle, the execution of the steps of the method for operating a fuel supply system for an internal combustion engine in particular of a motor vehicle on a computing device, in particular on a microprocessor in the control unit continuously. In this case, the invention is thus realized by a program stored on the storage medium, so that this storage medium provided with the program represents the invention in the same way as the method which the program is suitable for executing. In particular, an electrical storage medium may be used as the storage medium, for example a read-only memory (ROM) or an EPROM.

Weitere Merkmale, Anwendungsmöglichkeiten und Vorteile der Erfindung ergeben sich aus der nachfolgenden Beschreibung von Ausführungsbeispielen der Erfindung, die in den Figuren

Figur 1
zeigt ein erstes Ausführungsbeispiel der erfindungsgemäßen Vorrichtung,
Figur 2
zeigt ein zweites Ausführungsbeispiel der erfindungsgemäßen Vorrichtung,
Figur 3
zeigt ein Ausführungsbeispiel des erfindungsgemäßen Verfahrens,
Figur 4
zeigt ein erstes Detail des ersten Ausführungsbeispiels des erfindungsgemäßen Verfahrens und
Figur 5
zeigt ein zweites Detail des ersten Ausführungsbeispiels des erfindungsgemäßen Verfahrens.
Other features, applications and advantages of the invention will become apparent from the following description of embodiments of the invention, in the figures
FIG. 1
shows a first embodiment of the device according to the invention,
FIG. 2
shows a second embodiment of the device according to the invention,
FIG. 3
shows an embodiment of the method according to the invention,
FIG. 4
shows a first detail of the first embodiment of the method according to the invention and
FIG. 5
shows a second detail of the first embodiment of the method according to the invention.

Figur 1 zeigt ein erstes Ausführungsbeispiel der erfindungsgemäßen Vorrichtung. Im Bereich eines Kraftstoffvorratsbehälters 1 bzw. dem Tank des Kraftfahrzeugs ist eine erste Pumpe 2 angeordnet, die in der Regel als Elektrokraftstoffpumpe ausgeführt ist. Die Elektrokraftstoffpumpe 2 ist über eine Steuerleitung 4 mit dem Motorsteuergerät 3 verbunden. Über die Steuerleitung 4 kann das Motorsteuergerät beispielsweise Einfluss auf die Drehzahl und somit auf die Fördermenge der Elektrokraftstoffpumpe 2 nehmen. Die Elektrokraftstoffpumpe 2 befördert den Kraftstoff aus dem Tank 1 über eine erste Druckleitung 5 zu einer zweiten Pumpe 6. Die zweite Pumpe 6, die als eine elektrisch angetriebene Hochdruckpumpe ausgeführt ist, ist über eine Steuerleitung 7 mit dem Motorsteuergerät 3 verbunden. Die elektrische Hochdruckpumpe 6 befördert den Kraftstoff über eine zweite Druckleitung 8 in einen Druckspeicher 9, ein sogenanntes Common-Rail 9. Vom Common-Rail 9 ausgehend gelangt der unter hohen Druck gesetzte Kraftstoff über Druckleitungen 10 zu Einspritzventilen 11 (auch Injektoren genannt), mittels derer der Kraftstoff direkt in einen Brennraum 12 eingespritzt wird. Zur Ansteuerung der Einspritzventile 11 sind diese jeweils über eine Ansteuerleitung 13 mit dem Motorsteuergerät 3 verbunden. Zur Erfassung bzw. Messung des Drucks im Common-Rail 9 ist ein Drucksensor 14 im zweiten Druckbereich angeordnet, der ein einen Druck im Common-Rail 9 repräsentierendes Signal über die Signalleitung 15 an das Motorsteuergerät 3 überträgt. Weiterhin ist im Bereich des Common-Rails 9 ein einen Druck regelndes und/oder steuerndes Mittel 16 angeordnet. In diesem Ausführungsbeispiel ist das den Druck regelnde und/oder steuernde Mittel 16 als Drucksteuerventil ausgeführt. Der vom Drucksteuerventil 16 abfließende Kraftstoff gelangt über eine Kraftstoffleitung 18 zurück in den ersten Druckbereich 5, also in den Bereich vor die zweite Pumpe 6. Das Drucksteuerventil 16 ist über eine Steuerleitung 17 mit dem Motorsteuergerät 3 verbunden. Über die Steuerleitung 17 kann das Motorsteuergerät 3 Einfluss auf die Parameter des Ventils 16 nehmen. Dies kann beispielsweise die Einstellung eines vorbestimmten Druckniveaus im Common-Rail 9 sein, ab dessen Überschreitung der Überdruck, der im Common-Rail entstehen würde, dadurch abgebaut wird, dass der Kraftstoff über das Drucksteuerventil 16 zurück in den ersten Druckbereich abfließt (Überströmung). FIG. 1 shows a first embodiment of the device according to the invention. In the area of a fuel tank 1 or the tank of the motor vehicle, a first pump 2 is arranged, which is usually designed as an electric fuel pump. The electric fuel pump 2 is connected via a control line 4 to the engine control unit 3. Via the control line 4, the engine control unit, for example, influence the speed and thus take on the flow rate of the electric fuel pump 2. The electric fuel pump 2 conveys the fuel from the tank 1 via a first pressure line 5 to a second pump 6. The second pump 6, which is designed as an electrically driven high pressure pump, is connected via a control line 7 to the engine control unit 3. The high-pressure electric pump 6 conveys the fuel via a second pressure line 8 into a pressure accumulator 9, a so-called common rail 9. Starting from the common rail 9, the high-pressure fuel passes via pressure lines 10 to injectors 11 (also called injectors) by means of of which the fuel is injected directly into a combustion chamber 12. To control the injection valves 11, these are each connected via a control line 13 to the engine control unit 3. For detecting or measuring the pressure in the common rail 9, a pressure sensor 14 is arranged in the second pressure range, which transmits a signal representing a pressure in the common rail 9 via the signal line 15 to the engine control unit 3. Furthermore, a pressure-regulating and / or controlling means 16 is arranged in the region of the common rail 9. In this embodiment, the pressure regulating and / or controlling means 16 is designed as a pressure control valve. The fuel flowing off from the pressure control valve 16 passes through a fuel line 18 back into the first pressure range 5, ie in the area in front of the second pump 6. The pressure control valve 16 is connected via a control line 17 to the engine control unit 3. Via the control line 17, the engine control unit 3 can influence the parameters of the valve 16. This can be, for example, the setting of a predetermined pressure level in the common rail 9, beyond which the overpressure which would arise in the common rail is reduced by the fact that the fuel via the pressure control valve 16 flows back into the first pressure range (overflow).

Der Kern des erfindungsgemäßen Kraftstoffversorgungssystems ist eine Drehzahlregeleinrichtung 19 zur Ansteuerung der elektrischen Hochdruckpumpe 6. Hierzu ist die Drehzahlregeleinrichtung 19 mit einer Steuerleitung 20 mit dem Motorsteuergerät 3 verbunden. Entsprechend der Vorgaben/Ansteuersignale des Motorsteuergeräts 3, die über die Steuerleitung 20 an die Drehzahlregeleinrichtung 19 übertragen werden, wird eine entsprechende Ansteuerung der elektrischen Hochdruckpumpe 6 über die Leitung 21 vorgenommen.The core of the fuel supply system according to the invention is a speed control device 19 for controlling the electric high-pressure pump 6. For this purpose, the speed control device 19 is connected to a control line 20 to the engine control unit 3. According to the specifications / control signals of the engine control unit 3, which are transmitted via the control line 20 to the speed control device 19, a corresponding control of the electric high-pressure pump 6 is made via line 21.

Bei der elektrisch angetriebenen Hochdruckpumpe 6 kann es sich beispielsweise um einen elektrischen Asynchronmotor handeln, der mit einer mechanischen Pumpe gekoppelt ist. Es liegt weiterhin im Rahmen des erfindungsgemäßen Kraftstoffversorgungssystems, dass die Hochdruckpumpeneinheit 6 baulich getrennt von dem den Brennraum umschließenden Motorblock 23 angeordnet ist. Durch diese Anordnung ergeben sich thermische Vorteile, insbesondere in Heißstartsituationen sowie Vorteile in Bezug auf die Flexibilität beim Einbau des Systems in einen Motorraum eines Kraftfahrzeugs (besseres Packaging möglich). Innerhalb der Hochdruckpumpeneinheit 6 befindet sich ein Mengensteuerventil, das über die Steuerleitung 7, die das Motorsteuergerät 3 mit der Hochdruckpumpeneinheit 6 verbindet, angesteuert werden kann. Durch den Einsatz eines Mengensteuerventils innerhalb der Hochdruckpumpeneinheit 6 ist es möglich, über ein Ansteuersignal, die der Hochdruckpumpeneinheit 6 zugeführte Kraftstoffmenge festzulegen.The electrically driven high-pressure pump 6 may be, for example, an asynchronous electric motor which is coupled to a mechanical pump. It is also within the scope of the fuel supply system according to the invention that the high-pressure pump unit 6 is arranged structurally separate from the engine block 23 enclosing the combustion chamber. By this arrangement, there are thermal advantages, especially in hot start situations and advantages in terms of the flexibility in installing the system in an engine compartment of a motor vehicle (better packaging possible). Within the high-pressure pump unit 6 is a quantity control valve, which can be controlled via the control line 7, which connects the engine control unit 3 to the high-pressure pump unit 6. By using a quantity control valve within the high-pressure pump unit 6, it is possible, via a drive signal, to set the amount of fuel supplied to the high-pressure pump unit 6.

Das in den bisherigen Ausführungen als Motorsteuergerät 3 bezeichnete Steuergerät kann selbstverständlich im allgemeinen Fall ein spezielles Steuergerät sein, das ausschließlich die Ansteuerung der Komponenten des Kraftstoffversorgungssystems als Aufgabe hat. In diesem Fall kann das Steuergerät 3 auch zusammen mit der Drehzahlregeleinrichtung 19 und der Hochdruckpumpe 6 zu einer einzigen baulichen Einheit zusammengefasst werden. Die Zusammenfassung dieser Komponenten zu einer einzigen Steuer-, Regel- und Pumpeneinheit bietet insbesondere Vorteile beim Packaging im Motorraum und bringt für den Kfz-Hersteller den Vorteil, ein bestehendes Motorenkonzept besonders leicht und flexibel mit einem neuen Hochdruck-Kraftstoffversorgungssystem auszustatten.The controller referred to in the previous versions as the engine control unit 3 can of course be a special controller in the general case, which has only the control of the components of the fuel supply system as a task. In this case, the control unit 3 can also be combined together with the speed control device 19 and the high pressure pump 6 to form a single structural unit. The combination of these components into a single control, regulation and pump unit offers particular advantages in packaging in the engine compartment and brings the advantage for the motor vehicle manufacturer to equip an existing engine concept particularly easy and flexible with a new high-pressure fuel supply system.

Für den Fall, dass es sich bei dem Steuergerät 3 um das zentrale Motorsteuergerät des Kraftfahrzeugs handelt, sind diverse weitere Signalleitungen 22 angedeutet, die der Wahrnehmung der weiteren Funktionen des Motorsteuergeräts 3 dienen. Innerhalb des Steuergerätes 3 befindet sich erfindungsgemäß ein Speichermedium, auf dem ein Programm abgespeichert ist, dass die Ausführung der bisher geschilderten Funktion sowie die der Funktion des erfindungsgemäßen Verfahrens das im weiteren im Rahmen der Figuren 3 bis 5 eingehender erläutert wird, ermöglicht.In the event that the control unit 3 is the central engine control unit of the motor vehicle, various other signal lines 22 are indicated which serve to perceive the further functions of the engine control unit 3. Within the control unit 3 is according to the invention, a storage medium on which a program is stored, that the execution of the previously described function as well as the function of the method according to the invention in the further in the context of FIGS. 3 to 5 is explained in more detail, allows.

Von besonderer Bedeutung ist das erfindungsgemäße Kraftstoffversorgungssystem für eine Brennkraftmaschine, die nach dem Prinzip der Benzindirekteinspritzung (BDE-System) arbeitet. Bei einem solchen System ist jedem Brennraum wenigstens eine Zündkerze zugeordnet, mittels derer der Kraftstoff in dem Brennraum 12 entzündbar ist. Die Zündkerzen, von denen wenigstens eine pro Brennraum/Zylinder 12 der Brennkraftmaschine angeordnet ist, sind in der Darstellung nach Figur 1 (und auch Figur 2) nicht gezeigt.Of particular importance is the fuel supply system according to the invention for an internal combustion engine, which operates on the principle of gasoline direct injection (BDE system). In such a system, each combustion chamber is assigned at least one spark plug, by means of which the fuel in the combustion chamber 12 can be ignited. The spark plugs, of which at least one per combustion chamber / cylinder 12 of the internal combustion engine is arranged, are shown in the illustration FIG. 1 (and also FIG. 2 ) Not shown.

Weiterhin bieten solche Systeme die Möglichkeit, den Kraftstoff wenigstens in einer ersten Betriebsart während einer Verdichtungsphase und in einer zweiten Betriebsart während einer Ansaugphase einzuspritzen. Die zweite Betriebsart, während derer in die Ansaugphase des jeweiligen Brennraums 12 eingespritzt wird, entspricht näherungsweise der homogenen Luft-Gas-Mischung, die im Rahmen der konventionellen (nicht direkten) Einspritzung in den Brennraum gelangt. Die erste Betriebsart, während derer in die Verdichtungsphase des Brennraums eingespritzt wird, wird auch als Schichtbetrieb bzw. Schichtladung bezeichnet. Der Schichtbetrieb bietet sich insbesondere dann an, wenn keine hohen Leistungsanforderungen an die Brennkraftmaschine gestellt werden. In diesem Fall weist die Brennkraftmaschine in der Regel einen geringeren Kraftstoffbedarf auf als im homogenen Betrieb. Das erfindungsgemäße Kraftstoffversorgungssystem ist insbesondere während des Schichtbetriebs hervorragend dazu geeignet, die Brennkraftmaschine bedarfsgesteuert mit dem notwendigen Kraftstoff zu versorgen. Dies bedeutet, dass insbesondere während des Schichtbetriebs sowohl die Drehzahl der Vorförderpumpe 2 als auch die Drehzahl der Hochdruckpumpe 6 reduziert werden kann, was zu einem deutlich verringerten Energiebedarf der Pumpen 2 und/oder 6 führt. Eine weiterer Vorteil liegt darin, dass während des Betriebs mit verringerter Drehzahl der Pumpen 2 und/oder 6 die Belastung für die jeweilige Pumpe nicht so hoch ist wie bei maximaler Drehzahl und somit von einer längeren Lebensdauer der Pumpen 2 und/oder 6 ausgegangen werden kann. Das in die Hochdruckpumpe 6 integrierte Mengensteuerventil wird ebenfalls entsprechend reduziert angesteuert.Furthermore, such systems offer the possibility of injecting the fuel at least in a first operating mode during a compression phase and in a second operating mode during an intake phase. The second mode of operation, during which it is injected into the intake phase of the respective combustion chamber 12, corresponds approximately to the homogeneous air-gas mixture which enters the combustion chamber in the context of conventional (non-direct) injection. The first mode during which it is injected into the compression phase of the combustion chamber is also referred to as stratified charge or stratified charge. The shift operation is particularly suitable when no high power requirements are placed on the internal combustion engine. In this case, the internal combustion engine usually has a lower fuel requirement than in homogeneous operation. The fuel supply system according to the invention is particularly well suited during the shift operation to supply the internal combustion engine on demand with the necessary fuel. This means that, in particular during the shift operation, both the rotational speed of the prefeed pump 2 and the rotational speed of the high-pressure pump 6 can be reduced, which leads to a significantly reduced energy requirement of the pumps 2 and / or 6. Another advantage is that during operation with reduced speed of the pumps 2 and / or 6, the load for the respective pump is not as high as at maximum speed and thus can be assumed to have a longer life of the pump 2 and / or 6 , The integrated in the high pressure pump 6 quantity control valve is also controlled accordingly reduced.

Figur 2 zeigt ein zweites Ausführungsbeispiel der erfindungsgemäßen Vorrichtung, bei der gleiche Elemente mit den identischen Bezugszeichen gekennzeichnet sind. Der Unterschied dieses zweiten Ausführungsbeispiels im Vergleich zu dem in Figur 1 dargestellten Ausführungsbeispiel liegt in der Anordnung des Drucksteuerventils 16', das in diesem zweiten Ausführungsbeispiel in die Hochdruckpumpeneinheit 6 integriert ist bzw. an die Hochdruckpumpeneinheit 6 angebaut ist. Über das Drucksteuerventil 16' kann der überschüssige Kraftstoff über die Leitung 18' zurück in den ersten Druckbereich 5 vor die Hochdruckpumpe 6 fließen. Die Ansteuerung des Drucksteuerventils 16' erfolgt über eine Steuerleitung 17', die das Drucksteuerventil 16' mit dem Motorsteuergerät 3 verbindet. Der Vorteil der Integration des Drucksteuerventils 16' in die Hochdruckpumpeneinheit 6 liegt darin, dass hierdurch ein Hochdruckpumpenmodul geschaffen wird, das sich flexibel in bestehende Konzepte von Brennkraftmaschinen einbinden lässt. Mit anderen Worten: Es wird einem Kraftfahrzeughersteller erleichtert, eine bestehende Brennkraftmaschine auf eine Brennkraftmaschine mit Hochdruckeinspritzung umzurüsten. FIG. 2 shows a second embodiment of the device according to the invention, in which the same elements are identified by the identical reference numerals. Of the Difference of this second embodiment compared to the in FIG. 1 illustrated embodiment lies in the arrangement of the pressure control valve 16 ', which is integrated in this second embodiment in the high-pressure pump unit 6 and is attached to the high-pressure pump unit 6. Via the pressure control valve 16 ', the excess fuel can flow via the line 18' back into the first pressure range 5 in front of the high-pressure pump 6. The control of the pressure control valve 16 'via a control line 17', which connects the pressure control valve 16 'with the engine control unit 3. The advantage of the integration of the pressure control valve 16 'in the high pressure pump unit 6 is that this creates a high pressure pump module that can be flexibly integrated into existing concepts of internal combustion engines. In other words, it is made easier for a motor vehicle manufacturer to convert an existing internal combustion engine to an internal combustion engine with high-pressure injection.

Figur 3 zeigt ein Ausführungsbeispiel des erfindungsgemäßen Verfahrens, wobei in Figur 3 speziell die Ansteuerung des Drucksteuerventils 16 bzw. 16' gezeigt ist. Erfindungsgemäß werden in zwei Bestimmungseinheiten 31 und 32 zwei Teilsignale gebildet, die in einen Block 33 zu einem Gesamtsignal aufsummiert werden. Die für die Bestimmung der beiden Teilsignale von den Bestimmungseinheiten 31 und 32 benötigten Eingangssignale/Eingangsdaten werden auf direktem oder indirektem Weg von dem Motorsteuergerät 3 geliefert. Indirekt bedeutet hierbei, dass die Daten beispielsweise nicht über eine direkte Verbindung zwischen dem Motorsteuergerät 3 und den Bestimmungseinheiten 31 und 32 zur Verfügung gestellt werden, sondern dass die Übermittlung der Daten über ein Fahrzeug-Bus-System (CAN-Bus) erfolgt. In der Darstellung nach Figur 3 sind beispielhaft jeweils 3 Eingangsgrößen für die Bestimmungseinheiten 31 und 32 dargestellt. Diese Darstellung ist nur beispielhaft anzusehen und stellt keine Beschränkung der Erfindung dar. Es können also auch weniger oder mehr Eingangssignale verarbeitet werden. In der Bestimmungseinheit 31 wird ein Teilsignal generiert, das als Regelanteil bezeichnet werden kann, während in der Bestimmungseinheit 32 ein Teilsignal generiert wird, das als Vorsteueranteil bezeichnet werden kann. Hierbei wird der Regelanteil in der Bestimmungseinheit 31 in Abhängigkeit von dem im Common-Rail 9 vorherrschenden Druck-Ist-Wert und einem betriebspunktabhängigen Druck-Soll-Wert im Common-Rail 9 gebildet. Der Druck-Ist-Wert des Common-Rails 9 wird wie in Figur 1 erläutert mit dem Drucksensor 14 erfasst und gelangt über das Steuergerät 3 zur Bestimmungseinheit 31. Der betriebspunktabhängige Druck-Soll-Wert im Common-Rail 9 kann beispielsweise einem im Steuergerät 3 abgelegten applizierbaren Kennfeld entnommen werden. Der Vorsteueranteil, der in der Bestimmungseinheit 32 gebildet wird, wird wenigstens in Abhängigkeit von zuströmender und abströmender Kraftstoffmasse in bzw. aus dem Druckspeicher bestimmt. Die konkrete Bestimmung der zuströmenden bzw. abströmenden Kraftstoffmengen in bzw. aus dem Common-Rail 9 wird eingehend im Rahmen der Beschreibung zu Figur 3 erläutert. FIG. 3 shows an embodiment of the method according to the invention, wherein in FIG. 3 specifically the control of the pressure control valve 16 or 16 'is shown. According to the invention, two partial signals 31 and 32 are formed in two determination units, which are summed up in a block 33 to form a total signal. The input signals / input data required for the determination of the two partial signals from the determination units 31 and 32 are supplied by the engine control unit 3 directly or indirectly. Indirect here means that the data is not made available for example via a direct connection between the engine control unit 3 and the determination units 31 and 32, but that the transmission of data via a vehicle-bus system (CAN bus) takes place. In the illustration after FIG. 3 3 are exemplary input variables for the determination units 31 and 32 shown. This representation is to be regarded only as an example and does not represent a limitation of the invention. Thus, fewer or more input signals can also be processed. In the determination unit 31, a partial signal is generated, which can be referred to as a control component, while in the determination unit 32, a partial signal is generated, which can be referred to as a pilot proportion. Here, the control component in the determination unit 31 is formed in dependence on the prevailing in the common rail 9 pressure-actual value and an operating point-dependent pressure-target value in the common rail 9. The pressure-actual value of the common rail 9 is as in FIG. 1 explained with the pressure sensor 14 detected and passes through the control unit 3 to the determination unit 31. The operating point-dependent pressure-target value in the common rail 9 can be taken, for example, an administered in the control unit 3 applicable map. The pilot proportion, which is formed in the determination unit 32, is determined at least as a function of inflowing and outflowing fuel mass into and out of the pressure accumulator. The concrete determination of the inflowing or outflowing quantities of fuel into or out of the common rail 9 will be discussed in detail in the description FIG. 3 explained.

Nach der Summenbildung des Regelanteils und des Vorsteueranteils im Schritt 33 wird das Summensignal im Schritt 34 in ein entsprechendes Ansteuersignal für das Drucksteuerventil 16 bzw. 16' umgewandelt. Das resultierende Ansteuersignal, das in Schritt 34 gebildet wird, kann beispielsweise ein Tastverhältnis, eine Puls-Weiten-Modulation oder, falls ein Mengensteuerventil eingesetzt wird, beispielsweise eine Winkelansteuerung zwischen 0 und 180° sein.After the summation of the control component and the pilot control component in step 33, the composite signal is converted in step 34 into a corresponding control signal for the pressure control valve 16 or 16 '. The resulting drive signal, which is formed in step 34, may be, for example, a duty cycle, a pulse width modulation or, if a quantity control valve is used, for example an angle control between 0 and 180 °.

Figur 4 zeigt die Bildung des ersten Teilsignals zur Ansteuerung des Drucksteuerventils 16 bzw. 16', im Detail. Diejenigen Blöcke des Verfahrens, die der Bestimmungseinheit 31 nach Figur 3 entsprechen, sind mit einer gestrichelten Linie markiert und mit dem Bezugszeichen 31 versehen. Die in Figur 4 dargestellten Verfahrensschritte 41 und 42 stellen die Ist-Wert-Erfassung des Drucks im Common-Rail 9 dar, während der Verfahrensschritt 44 die Soll-Wert-Bildung des Drucks im Common-Rail 9 symbolisiert. Im Schritt 43 wird aus der Differenz aus Soll- und Ist-Wert des Drucks im Common-Rail 9 die Soll-Ist-Regeldifferenz gebildet. Im Schritt 45 wird die Regeldifferenz, die im Schritt 43 bestimmt worden ist, mit einem PI-Regler oder einem PID-Regler in das entsprechende erste Teilsignal zur Ansteuerung des Drucksteuerventils 16 bzw. 16' umgewandelt und an den Verfahrensschritt 33 entsprechend Figur 3 übergeben. FIG. 4 shows the formation of the first partial signal for controlling the pressure control valve 16 or 16 ', in detail. Those blocks of the method that the determination unit 31 after FIG. 3 are marked with a dashed line and provided with the reference numeral 31. In the FIG. 4 illustrated method steps 41 and 42 represent the actual value detection of the pressure in the common rail 9, while the process step 44 symbolizes the target value formation of the pressure in the common rail 9. In step 43, the target actual control difference is formed from the difference between the setpoint and actual value of the pressure in the common rail 9. In step 45, the control difference, which has been determined in step 43, is converted with a PI controller or a PID controller into the corresponding first partial signal for controlling the pressure control valve 16 or 16 'and corresponding to the method step 33 FIG. 3 to hand over.

Die Ist-Wert-Erfassung in den Schritten 41 und 42 erfolgt dadurch, dass vom Drucksensor 14, der den Druck im Common-Rail 9 erfasst, ein einen Druck repräsentierendes Signal an den Verfahrensschritt 41 übergeben wird. In Schritt 41 wird somit das einen Druck charakterisierende Signal des Drucksensors 14 erfasst und zur Filterung an den Schritt 42 weitergeleitet. In Schritt 42 findet beispielsweise eine Tiefpassfilterung statt, um hochfrequente Störungen aus dem Drucksignal herauszufiltern. Das Ergebnis des Schritts 42 ist das Ist-Signal des Drucks im Common-Rail 9, das an den Schritt 43 weitergeleitet wird.The actual value detection in steps 41 and 42 takes place in that the pressure sensor 14, which detects the pressure in the common rail 9, transfers a signal representing a pressure to method step 41. In step 41, the pressure-characterizing signal of the pressure sensor 14 is thus detected and forwarded to the step 42 for filtering. In step 42, for example, a low-pass filtering takes place in order to filter out high-frequency interference from the pressure signal. The result of step 42 is the actual signal of the pressure in the common rail 9, which is forwarded to step 43.

Im Schritt 44 des erfindungsgemäßen Verfahrens wird entsprechend der aktuellen Betriebsdaten aus einem betriebspunktabhängigen Kennfeld, das im Steuergerät 3 abgelegt ist, ein Soll-Wert für den Druck im Common-Rail 9 entnommen/gebildet und an Schritt 43 übertragen.In step 44 of the method according to the invention, a desired value for the pressure in the common rail 9 is taken / formed in accordance with the current operating data from an operating point-dependent characteristic field, which is stored in the control unit 3, and transmitted to step 43.

Im Schritt 32 nach Figur 3 wurde der Vorsteueranteil zur Ansteuerung des Drucksteuerventils 16 bzw. 16' u. a. auf Grundlage der zuströmenden bzw. abströmenden Kraftstoffmenge in bzw. aus dem Common-Rail 9 bestimmt. Die hierzu erforderliche Bestimmung der Mengenbilanz wird im Folgenden im Rahmen der Figur 5 erläutert. Dargestellt ist wiederum das Motorsteuergerät 3, das für die Verfahrensschritte 51, 53 und 55 alle notwendigen Eingangsgrößen liefert.In step 32 after FIG. 3 was the pilot component for controlling the pressure control valve 16 and 16 ', inter alia, based on the inflowing or outflowing amount of fuel in or out of the common rail 9 determined. The determination of the quantity balance required for this purpose is described below in the context of FIG. 5 explained. Shown again is the engine control unit 3, which supplies all necessary input variables for the method steps 51, 53 and 55.

Im Schritt 51 wird die dem Common-Rail 9 zuströmende Kraftstoffmenge bestimmt. Diese Kraftstoffmenge ergibt sich proportional zu dem Produkt aus Wirkungsgrad der elektrischen Hochdruckpumpe 6, Drehzahl der elektrischen Hochdruckpumpe 6 und Tastverhältnis des in die Hochdruckpumpe 6 integrierten Mengensteuerventils (oder eines äquivalenten Ansteuersignals für das Mengensteuerventil).In step 51, the amount of fuel flowing to the common rail 9 is determined. This amount of fuel is proportional to the product of efficiency of the electric high-pressure pump 6, speed of the electric high-pressure pump 6 and duty cycle of the integrated in the high-pressure pump 6 quantity control valve (or an equivalent drive signal for the quantity control valve).

Im Schritt 53 wird die Kraftstoffmenge bestimmt, die über die Injektoren 11 in die Brennräume der Brennkraftmaschine eingespritzt wird. Diese Kraftstoffmenge ergibt sich proportional zu dem Produkt aus der im Motorsteuergerät 3 bestimmten Kraftstoffmenge je Einspritzung und der Drehzahl der Brennkraftmaschine.In step 53, the fuel quantity is determined, which is injected via the injectors 11 into the combustion chambers of the internal combustion engine. This amount of fuel is proportional to the product of the determined in the engine control unit 3 amount of fuel per injection and the speed of the internal combustion engine.

Im Schritt 55 wird die Kraftstoffmenge bestimmt, die über das Drucksteuerventil 16 bzw. 16' zurück in den ersten Druckbereich vor die elektrische Hochdruckpumpe 6 überströmt. Die entsprechende überströmende Kraftstoffmenge des Drucksteuerventils wird wenigstens in Abhängigkeit von dem Ansteuersignal bzw. dem Tastverhältnis des Drucksteuerventils und dem derzeit vorherrschenden Druck im Common-Rail 9 aus einem applizierbaren Kennfeld im Motorsteuergerät 3 entnommen.In step 55, the fuel quantity is determined, which flows via the pressure control valve 16 or 16 'back into the first pressure range in front of the electric high-pressure pump 6. The corresponding overflowing amount of fuel of the pressure control valve is taken from an applicable map in the engine control unit 3 at least as a function of the drive signal or the duty cycle of the pressure control valve and the currently prevailing pressure in the common rail 9.

Im Folgenden wird nun von der in Schritt 51 bestimmten, dem Common-Rail 9 zugeführten, Kraftstoffmenge die in Schritt 53 bestimmte, durch die Einspritzung in die Brennräume aus dem Common-Rail 9 abströmende, Kraftstoffmasse abgezogen. Dieser Schritt der Differenzbildung ist mit 52 gekennzeichnet. Das Ausgangssignal des Verfahrensschritts 52 wird zu einem weiteren Differenzglied im Schritt 54 übertragen, in dem zudem die im Schritt 55 bestimmte Überströmmenge des Drucksteuerventils 16 bzw. 16' abgezogen wird. Das Ergebnis des Verfahrensschritts 54 ist die dem Common-Rail 9 effektiv zuströmende Kraftstoffmenge, praktisch also die Erhöhung der Kraftstoffmenge im Common-Rail 9. Diese Daten werden zurück an das Steuergerät 3 übertragen, das diese Daten dem Verfahrensschritt 32 nach Figur 3 zur Verfügung stellen kann.In the following text, the fuel quantity determined in step 53 and fed to the common rail 9 in step 51 will be subtracted from the fuel mass determined in step 53 and discharged through the injection into the combustion chambers from the common rail 9. This step of subtraction is indicated at 52. The output signal of method step 52 is transmitted to a further differential element in step 54, in which, in addition, the overflow quantity of pressure control valve 16 or 16 'determined in step 55 is subtracted. The result of method step 54 is the quantity of fuel effectively flowing in to the common rail 9, in practice thus the increase in the fuel quantity in the common rail 9. These data are transmitted back to the control unit 3, which transfers this data to method step 32 FIG. 3 can provide.

Im allgemeinen Fall sind die in den Figuren 3, 4 und 5 dargestellten Verfahrensschritte im Motorsteuergerät 3 integriert, so dass die in den Figuren 3, 4 und 5 dargestellte Übergabe von Informationen/Daten vom Motorsteuergerät 3 an die Verfahrensschritte 31, 32, 41, 44, 51, 53 und 55 im allgemeinen Fall einen internen Vorgang im Steuergerät darstellt. Ebenso die Übergabe der bestimmten Kraftstoffmenge vom Schritt 54 an das Steuergerät 3. Es liegt jedoch auch im Rahmen des erfindungsgemäßen Verfahrens, dass die Verfahrensschritte entsprechend der Figuren 3, 4 und 5 von einem separaten Steuergerät durchgeführt werden, das nicht in das Motorsteuergerät 3 integriert ist. In diesem Fall kann das separate Steuergerät, wie bereits im Rahmen der Beschreibung der erfindungsgemäßen Vorrichtung nach den Figuren 1 und 2 erläutert, in die bauliche Einheit der elektrisch angetriebenen Hochdruckpumpe 6 integriert sein.In the general case, those in the FIGS. 3, 4 and 5 integrated process steps in the engine control unit 3, so that in the FIGS. 3, 4 and 5 represented transfer of information / data from the engine control unit 3 to the process steps 31, 32, 41, 44, 51, 53 and 55 represents an internal process in the control unit in the general case. Likewise, the transfer of the specific amount of fuel from step 54 to the control unit 3. It is also within the scope of the method according to the invention that the method steps corresponding to FIGS. 3, 4 and 5 be performed by a separate control unit, which is not integrated into the engine control unit 3. In this case, the separate control unit, as already in the context of the description of the device according to the invention according to the FIGS. 1 and 2 explained, be integrated into the structural unit of the electrically driven high-pressure pump 6.

Eine weitere Möglichkeit die Ansteuerung für das Kraftstoffversorgungssystem im Rahmen des erfindungsgemäßen Verfahrens zu verbessern liegt darin, dass die Drehzahl der Hochdruckpumpe 6 bei der Vorsteuerung der Elektrokraftstoffpumpe 2 berücksichtigt wird. Hierzu kann im Steuergerät 3 ein applizierbares Kennfeld abgelegt sein, das in Abhängigkeit von der bestimmten Soll-Drehzahl der Hochdruckpumpe 6 einen Korrekturfaktor und/oder einen Korrekturoffset für das Ansteuersignal (zur Drehzahlregelung) der Elektrokraftstoffpumpe bestimmt.Another possibility to improve the control for the fuel supply system in the context of the method according to the invention is that the speed of the high pressure pump 6 is taken into account in the feedforward control of the electric fuel pump 2. For this purpose, an applicable map can be stored in the control unit 3, which determines a correction factor and / or a correction offset for the drive signal (for speed control) of the electric fuel pump in dependence on the specific target speed of the high-pressure pump 6.

Claims (10)

  1. Method for operating a fuel supply system for an internal combustion engine, in particular of a motor vehicle,
    - in which fuel is conveyed into a first pressure region (5) by means of at least one first pump (2),
    - in which the fuel is conveyed out of the first pressure region (5) into a second pressure region (8) having at least one pressure accumulator (9) by means of at least one second, electrically operated pump (6),
    - in which the fuel is injected out of the second pressure region (8, 9) directly into a combustion space (12) by means of injection valves (11),
    - in which the pressure in the second pressure region (8, 9) is detected by means of a pressure sensor (14),
    - in which the pressure in the second pressure region (8, 9) is regulated by means of a pressure control valve (16, 16') which is arranged in the second pressure region (8, 9),
    - in which the second pump (6) is activated (19, 20, 21) in its rotational speed,
    characterized in that
    - an activation signal for activating the pressure control valve is generated (31, 32, 33, 34), and in that
    - a desired rotation speed of the second pump (6) is determined at least as a function of the fuel quantity required for combustion and of the overflow quantity required for the pressure control valve.
  2. Method according to Claim 1, characterized in that the first pump (2) is activated and/or regulated in such a way that at least the fuel quantity required by the engine is conveyed into the first pressure region (5).
  3. Method according to Claim 1, characterized in that the activation signal for activating the pressure control valve (16, 16') is formed (33) from the sum of two independent part-signals.
  4. Method according to Claim 3, characterized in that the first part-signal (31) is formed at least as a function of a pressure actual value (41, 42) and of an operating-point-dependent pressure desired value (44) in the second pressure region (8, 9).
  5. Method according to Claim 3, characterized in that the second part-signal (32) is determined at least as a function of the inflowing (51) and outflowing (53, 55) fuel mass respectively into and out of the pressure accumulator (9).
  6. Method according to Claim 5, characterized in that the second part-signal (32) is taken from an applicable characteristic map.
  7. Fuel supply system for an internal combustion engine, in particular of a motor vehicle,
    - with at least one first pump (2), by means of which fuel can be conveyed into a first pressure medium (5),
    - with at least one second, electrically operated pump (6), by means of which the fuel can be conveyed out of the first pressure region (5) into a second pressure region (8) having at least one pressure accumulator (9),
    - with injection valves (11), by means of which the fuel can be injected out of the second pressure region (8, 9) directly into a combustion space (12),
    - with a pressure sensor (14), by means of which the pressure in the second pressure region (8, 9) is detected,
    - with a pressure control valve (16, 16'), which is arranged in the second pressure region (8, 9) and by means of which the pressure in the second pressure region (8, 9) can be regulated,
    - first means (19, 20, 21) being present, by which the second pump (6) can be activated in its rotational speed,
    characterized in that
    - a means (3) for generating an activation signal for the pressure control valve (16, 16') is present,
    and in that
    - the first means (19, 20, 21) are set up in such a way that these means (19, 20, 21) determine a desired rotational speed of the second pump (6) as a function of at least the fuel quantity required for combustion and of the overflow quantity required for the pressure control valve.
  8. Fuel supply system according to Claim 7,
    characterized in that the pressure control valve (16, 16') and the second pump (6) form a structural unit or a pressure control valve (16, 16') is integrated into the second pump (6).
  9. Control apparatus for an internal combustion engine, in particular of a motor vehicle, characterized in that means for carrying out all the steps of the method according to at least one of Claims 1 to 6 are present.
  10. Storage medium for a control apparatus of an internal combustion engine, in particular of a motor vehicle, in which is stored a program which on a computer, in particular on a microprocessor in the control apparatus, continuously implements the execution of all the steps of the method according to one of Claims 1 to 6.
EP20010116806 2000-08-03 2001-07-10 Fuel supply system for internal combustion engine especially in a motor vehicle Expired - Lifetime EP1178205B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10038555 2000-08-03
DE2000138555 DE10038555A1 (en) 2000-08-03 2000-08-03 Fuel supply system for an internal combustion engine, in particular of a motor vehicle

Publications (3)

Publication Number Publication Date
EP1178205A2 EP1178205A2 (en) 2002-02-06
EP1178205A3 EP1178205A3 (en) 2004-01-02
EP1178205B1 true EP1178205B1 (en) 2008-05-14

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JP (1) JP2002106400A (en)
DE (2) DE10038555A1 (en)
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8539934B2 (en) 2008-04-10 2013-09-24 Bosch Corporation Injection abnormality detection method and common rail fuel injection control system
JP5235968B2 (en) * 2010-10-26 2013-07-10 三菱電機株式会社 Fuel supply system

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2689226B2 (en) * 1994-12-02 1997-12-10 株式会社ゼクセル Fuel pump for high pressure fuel injector
JPH08210209A (en) * 1995-02-06 1996-08-20 Zexel Corp High pressure fuel injector
JP3265997B2 (en) * 1996-08-20 2002-03-18 三菱自動車工業株式会社 Control device for internal combustion engine
DE19739653A1 (en) * 1997-09-10 1999-03-11 Bosch Gmbh Robert Process for producing high-pressure fuel and system for producing high-pressure fuel
DE19742993C2 (en) * 1997-09-29 2000-03-02 Siemens Ag Method of controlling fuel pressure in a fuel rail
FR2775319B1 (en) * 1998-02-26 2000-04-28 Sagem DIRECT FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINE
JP2000008926A (en) * 1998-06-29 2000-01-11 Hitachi Ltd Fuel control device for cylinder injection engine
DE19853823A1 (en) * 1998-11-21 2000-05-25 Bosch Gmbh Robert Method of operating internal combustion engine, especially for motor vehicle, involves controlling fuel pump delivery rate depending on input parameters via characteristic field
DE19903272A1 (en) * 1999-01-28 2000-08-03 Bosch Gmbh Robert Fuel supply system for an internal combustion engine, in particular of a motor vehicle

Also Published As

Publication number Publication date
DE50113962D1 (en) 2008-06-26
EP1178205A2 (en) 2002-02-06
JP2002106400A (en) 2002-04-10
EP1178205A3 (en) 2004-01-02
ES2304363T3 (en) 2008-10-16
DE10038555A1 (en) 2002-02-21

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