EP1088981A2 - Method to decrease the pressure in the common rail of an internal combustion engine - Google Patents

Method to decrease the pressure in the common rail of an internal combustion engine Download PDF

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Publication number
EP1088981A2
EP1088981A2 EP00108928A EP00108928A EP1088981A2 EP 1088981 A2 EP1088981 A2 EP 1088981A2 EP 00108928 A EP00108928 A EP 00108928A EP 00108928 A EP00108928 A EP 00108928A EP 1088981 A2 EP1088981 A2 EP 1088981A2
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EP
European Patent Office
Prior art keywords
rail
pressure
dav
valve
reducing valve
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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.)
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Application number
EP00108928A
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German (de)
French (fr)
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EP1088981A3 (en
Inventor
Andreas Kellner
Juergen Hammer
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP1088981A2 publication Critical patent/EP1088981A2/en
Publication of EP1088981A3 publication Critical patent/EP1088981A3/en
Withdrawn legal-status Critical Current

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    • 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
    • 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 reducing the rail pressure in a common rail system for internal combustion engines according to the Preamble of the main claim.
  • the pressure relief valve in internal combustion engines with one Common rail system has the task in the two-digit concept of the Pressure control circuit with throttled high pressure pump, the Pressure reduction in certain operating points of the internal combustion engine to accomplish.
  • the function of the pressure relief valve occurs preferably in thrust and in so-called empty gas bursts in Force.
  • the pressure relief valve takes over as an actuator in the pressure control loop the Pressure reduction function.
  • DE 195 48 278 describes a method and a device to regulate the pressure in a memory of a common rail system described. To control the pressure, a Control quantity drained from the accumulator into a low pressure area. Furthermore, it is provided that a second controller on the Low pressure area acts.
  • DE 197 31 994 describes a method and a device for controlling an internal combustion engine with a common rail System known in which a pressure control valve or pressure relief valve the rail with the fuel tank connected is.
  • the pressure control or release valve is via a Coil controllable.
  • the present invention is therefore based on the object the pressure reduction in certain individual operating points of the Internal combustion engine faster and faster via the pressure relief valve adapted to accomplish.
  • the invention has the main advantages that the pressure reduction according to a target pressure specification with high control quality. It this results in a minimization of the tax amount via the Pressure relief valve.
  • the use of the pressure relief valve structure is freely selectable in the engine operating map.
  • the valve seat wear at the pressure relief valve by adjusting the switching limits minimized (minimizing the number of switching operations).
  • the fuel denotes a fuel reservoir. This stands above a first filter 105, preferably one controllable feed pump 110 with a second filter 115 in Connection.
  • the fuel passes from the second filter 115 a line to a valve 120.
  • the connecting line stands between the filter medium 115 and the valve 120 Low pressure relief valve 140 with reservoir 100 in Connection.
  • the valve 120 is the metering unit ZME 122 and communicates with a high pressure pump 125.
  • the metering unit ZME is on the suction side of the high pressure pump arranged.
  • a solenoid-controlled proportional valve can be used can be controlled via the coil 122.
  • the high pressure pump is connected to a rail 130.
  • the rail is also called memory and survives Fuel lines with various injectors 131 in Contact.
  • Via a pressure control valve or pressure relief valve 135 is the rail 130 with the fuel tank 100 connectable.
  • the pressure control valve or pressure relief valve 135 can be controlled by means of a coil 136.
  • the lines between the outlet of the high pressure pump 125 and the inlet of the pressure control valve or pressure relief valve 135 are referred to as the high pressure area. In this area it says the fuel under high pressure.
  • the pressure in High pressure area, especially in the storage, is by means of a Sensor 145 detects.
  • the lines between the tank 100 and the High pressure pump 125 are referred to as a low pressure area.
  • a controller 160 includes a pressure regulator and acts on the corresponding control elements, such as for example, coil 136 of the pressure control valve or pressure relief valve 135 and / or the metering unit 122, with Control signals.
  • the controller 160 processes various Signals from various sensors 165 and 166 that the Operating state of the internal combustion engine and / or the Motor vehicle that drives the internal combustion engine characterize. Such an operating state is for example the speed N of the internal combustion engine or a Temperature value.
  • control system has further or controls other control elements.
  • control elements are used.
  • This facility works as follows: The fuel that is is located in the reservoir, the feed pump 110 promoted by the filter means 105 and 115. Output side of the pre-feed pump 110 is the fuel with a pressure of some bar.
  • the design of the low pressure area in particular the Arrangement of the valves and filters is only an example shown.
  • the type, arrangement and / or number of Items can also be different.
  • the high pressure pump 125 delivers the fuel from Low pressure area in the high pressure area.
  • the high pressure pump 125 builds up a very high pressure in the Rail 130.
  • Pressure values from about 30 to 100 bar and with auto-igniting Internal combustion engines pressure values from about 1000 to 2000 bar achieved.
  • the fuel can be injected via the injectors 131 high pressure of the individual cylinders of the internal combustion engine be measured.
  • the pressure in the rail or in the whole is measured by means of the sensor 145 High pressure area detected.
  • the pressure is on the metering unit ZME 120 regulated, which can be controlled with a coil 122 and which can adjust the delivery rate of the high pressure pump 125.
  • the pressure relief valve 135, which has a coil 136 can be controlled, the pressure in the high-pressure area can quickly be dismantled.
  • Mechanical feed pumps 110 are usually used Prefeed pumps used. But it can also Electric fuel pumps with a direct current motor (DC motors) or an electrically commutated DC motor (EC motors) can be used. For higher flow rates, the can be required in particular in the case of commercial vehicles several pre-feed pumps connected in parallel were also used become. In this case, because of the longer life and higher availability preferably used EC motors.
  • DC motors direct current motor
  • EC motors electrically commutated DC motor
  • the delivery rate QP is in the rail 130 funded. Via the pressure relief valve 135, the amount QDAV drained into the low pressure area. The amount of pressure build-up QR is available for pressure build-up. About the injectors 131, the metering quantity QI reaches the injectors 131. The quantity QI is made up of the amount of fuel injected QK, the amount of leakage and a control amount of the injectors. The Leakage amount and the tax amount get back into the Low pressure range. The amount of fuel injected arrives into the internal combustion engine.
  • ⁇ tein / aus represents the minimum time that elapses between an opening and an immediate closing process.
  • ⁇ traster is the time that is required to query the opening and closing process. The conditions apply: ⁇ on / off ⁇ traster + ⁇ aus, as well ⁇ out ⁇ traster
  • the first map Dp (p Rail) and the second map Dp to (p Rail) are dimensioned by the mathematical-physical relationships such that Dp (p Rail) the minimal displayable pressure difference Dp on for an opening and closing operation of the pressure Represents dismantling valve and the second characteristic diagram ⁇ p zu (p Rail ) represents the minimally acceptable pressure difference ⁇ p zu , which ensures that the pressure reducing valve can be closed without undershoot of the actual pressure.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

The rail pressure regulation method uses a pressure valve and an associated electronic control device, for controlling the valve in dependence on the difference between the required and actual rail pressure within the common-rail fuel injection system, with provision of variable hysteresis limits for the opening and closing of the pressure valve, at least one of which is dependent on the rail pressure.

Description

Die Erfindung betrifft ein Verfahren zum Abbau des Rail-Drucks in einem Common-Rail-System für Brennkraftmaschinen gemäß dem Oberbegriff des Hauptanspruchs.The invention relates to a method for reducing the rail pressure in a common rail system for internal combustion engines according to the Preamble of the main claim.

Das Druck-Abbau-Ventil bei Brennkraftmaschinen mit einem Common-Rail-System hat die Aufgabe, im Zwei-Steller-Konzept des Druckregelkreises mit sauggedrosselter Hochdruckpumpe, den Druckabbau in bestimmten Betriebspunkten der Brennkraftmaschine zu bewerkstelligen. Die Funktion des Druck-Abbau-Ventils tritt vorzugsweise im Schub und bei sogenannten Leergasstößen in Kraft.The pressure relief valve in internal combustion engines with one Common rail system has the task in the two-digit concept of the Pressure control circuit with throttled high pressure pump, the Pressure reduction in certain operating points of the internal combustion engine to accomplish. The function of the pressure relief valve occurs preferably in thrust and in so-called empty gas bursts in Force.

In heutigen Common-Rail-Systemen übernimmt das Druck-Abbau-Ventil als Stellglied im Druckregelkreis u.a. die Druckabbaufunktion.In today's common rail systems, the pressure relief valve takes over as an actuator in the pressure control loop the Pressure reduction function.

Aus der DE 195 48 278 sind ein Verfahren und eine Vorrichtung zur Regelung des Drucks in einem Speicher eines Common-Rail-Systems beschrieben. Zur Regelung des Drucks wird eine Regelmenge vom Speicher in einen Niederdruckbereich abgelassen. Desweiteren ist vorgesehen, daß ein zweiter Regler auf den Niederdruckbereich einwirkt.DE 195 48 278 describes a method and a device to regulate the pressure in a memory of a common rail system described. To control the pressure, a Control quantity drained from the accumulator into a low pressure area. Furthermore, it is provided that a second controller on the Low pressure area acts.

Aus der DE 197 31 994 ist ein Verfahren und eine Vorrichtung zur Steuerung einer Brennkraftmaschine mit einem Common Rail System bekannt, bei dem über ein Druckregelventil oder Druck-Abbau-Ventil das Rail mit dem Kraftstoffvorratsbehälter verbunden ist. Das Druckregel- oder Abbauventil ist über eine Spule steuerbar. DE 197 31 994 describes a method and a device for controlling an internal combustion engine with a common rail System known in which a pressure control valve or pressure relief valve the rail with the fuel tank connected is. The pressure control or release valve is via a Coil controllable.

In weiten Betriebsbereichen einer Brennkraftmaschine ist das Druck-Abbau-Ventil geschlossen. Die Regelung des Hochdrucks erfolgt dabei über den Mengensteller, welcher der Hochdruck-Pumpe eine Menge zwischen 0 und 100% zumißt. Für den Druckabbau ist dabei die Einspritz-, Steuer- und Leckagemenge an den Injektoren ausreichend.In wide operating areas of an internal combustion engine that is Pressure relief valve closed. The regulation of the high pressure takes place via the volume control, which is the high pressure pump measures an amount between 0 and 100%. For pressure reduction is the injection, control and leakage quantity to the Injectors sufficient.

Jedoch in einzelnen Betriebspunkten der Brennkraftmaschine wie z.B. im Schubbetrieb oder bei Leergasstößen ist dieser Druckabbau zu langsam, so daß es hierdurch zu unakzeptablen Geräuschen der Brennkraftmaschine bei Wiederaufnahme der Last kommen kann.However, in individual operating points of the internal combustion engine such as e.g. this is in overrun mode or in the event of empty gas surges Depressurization too slow, making it unacceptable Noise of the internal combustion engine when the load is resumed can come.

Hier kommt der Druckabbau durch das Druckabbau-Ventil zum Tragen.This is where the pressure reduction comes through the pressure reduction valve Wear.

Der vorliegenden Erfindung liegt daher die Aufgabe zugrunde, den Druckabbau in bestimmten einzelnen Betriebspunkten der Brennkraftmaschine über das Druck-Abbau-Ventil schneller und angepaßt zu bewerkstelligen.The present invention is therefore based on the object the pressure reduction in certain individual operating points of the Internal combustion engine faster and faster via the pressure relief valve adapted to accomplish.

Diese Aufgabe wird erfindungsgemäß durch den kennzeichnenden Teil des Hauptanspruchs gelöst.This object is achieved by the characterizing Part of the main claim solved.

Die Erfindung hat die wesentlichen Vorteile, daß der Druckabbau gemäß einer Solldruckvorgabe mit hoher Regelgüte erfolgt. Es ergibt sich dadurch eine Minimierung der Absteuermenge über das Druckabbauventil. Der Einsatz der Druckabbauventil-Struktur ist im Motorbetriebskennfeld frei wählbar. Der Ventilsitzverschleiß am Druckabbauventil ist durch Anpassung der Schaltgrenzen minimiert (Minimierung der Anzahl von Schaltvorgängen).The invention has the main advantages that the pressure reduction according to a target pressure specification with high control quality. It this results in a minimization of the tax amount via the Pressure relief valve. The use of the pressure relief valve structure is freely selectable in the engine operating map. The valve seat wear at the pressure relief valve by adjusting the switching limits minimized (minimizing the number of switching operations).

Weitere vorteilhafte Ausgestaltungen der Erfindung ergeben sich aus den Unteransprüchen. Further advantageous embodiments of the invention result from the subclaims.

Ein Ausführungsbeispiel der Erfindung ist in den Figuren dargestellt.An embodiment of the invention is in the figures shown.

Es zeigen:

Fig. 1:
ein Zeitdiagramm für den Öffnungs- und Schließvorgang des Druck-Abbau-Ventils,
Fig. 2:
die Durchflußrate als Funktion der Druckdifferenz,
Fig. 3:
den Druckverlauf im Rail bei einem Öffnungs-Schließvorgang,
Fig. 4:
die parametrisierten Kennfelder Δpauf und Δpzu als Funktion des Raildrucks,
Fig. 5:
ein Struktogramm,
Fig. 6:
ein Blockschaltbild.
Show it:
Fig. 1:
a time diagram for the opening and closing process of the pressure relief valve,
Fig. 2:
the flow rate as a function of the pressure difference,
Fig. 3:
the pressure curve in the rail during an opening-closing process,
Fig. 4:
the parametric maps Dp and Dp to as a function of the rail pressure,
Fig. 5:
a structogram,
Fig. 6:
a block diagram.

In Fig. 6 sind die für das Verständnis der Erfindung erforderlichen Bauteile eines Kraftstoffversorgungssystems einer Brennkraftmaschine mit Hochdruckeinspritzung dargestellt. Das dargestellte System wird üblicherweise als Common-Rail-System bezeichnet.6 are for understanding the invention required components of a fuel supply system an internal combustion engine with high pressure injection shown. The system shown is usually called a common rail system designated.

Mit 100 ist ein Kraftstoffvorratsbehälter bezeichnet. Dieser steht über ein erstes Filter 105, einer vorzugsweise steuerbaren Vorförderpumpe 110 mit einem zweiten Filter 115 in Verbindung. Vom zweiten Filter 115 gelangt der Kraftstoff über eine Leitung zu einem Ventil 120. Die Verbindungsleitung zwischen dem Filtermittel 115 und dem Ventil 120 steht über ein Niederdruckbegrenzungsventil 140 mit dem Vorratsbehälter 100 in Verbindung. Das Ventil 120 ist die Zumeßeinheit ZME 122 und steht mit einer Hochdruckpumpe 125 in Verbindung. 100 denotes a fuel reservoir. This stands above a first filter 105, preferably one controllable feed pump 110 with a second filter 115 in Connection. The fuel passes from the second filter 115 a line to a valve 120. The connecting line stands between the filter medium 115 and the valve 120 Low pressure relief valve 140 with reservoir 100 in Connection. The valve 120 is the metering unit ZME 122 and communicates with a high pressure pump 125.

Die Zumeßeinheit ZME ist saugseitig an der Hochdruckpumpe angeordnet. Als Zumeßeinheit kann beispielsweise ein magnetgesteuertes Proportionalventil eingesetzt werden, das über die Spule 122 steuerbar ist.The metering unit ZME is on the suction side of the high pressure pump arranged. For example, a solenoid-controlled proportional valve can be used can be controlled via the coil 122.

Die Hochdruckpumpe ist mit einem Rail 130 verbunden. Das Rail wird auch als Speicher bezeichnet und steht über Kraftstoffleitungen mit verschiedenen Injektoren 131 in Kontakt. Über ein Druckregelventil oder Druck-Abbau-Ventil 135 ist das Rail 130 mit dem Kraftstoffvorratsbehälter 100 verbindbar. Das Druckregelventil oder Druck-Abbau-Ventil 135 ist mittels einer Spule 136 steuerbar.The high pressure pump is connected to a rail 130. The rail is also called memory and survives Fuel lines with various injectors 131 in Contact. Via a pressure control valve or pressure relief valve 135 is the rail 130 with the fuel tank 100 connectable. The pressure control valve or pressure relief valve 135 can be controlled by means of a coil 136.

Die Leitungen zwischen dem Ausgang der Hochdruckpumpe 125 und dem Eingang des Druckregelventils oder Druck-Abbau-Ventils 135 werden als Hochdruckbereich bezeichnet. In diesem Bereich steht der Kraftstoff unter hohem Druck. Der Druck im Hochdruckbereich, insbesondere im Speicher, wird mittels eines Sensors 145 erfaßt. Die Leitungen zwischen dem Tank 100 und der Hochdruckpumpe 125 werden als Niederdruckbereich bezeichnet.The lines between the outlet of the high pressure pump 125 and the inlet of the pressure control valve or pressure relief valve 135 are referred to as the high pressure area. In this area it says the fuel under high pressure. The pressure in High pressure area, especially in the storage, is by means of a Sensor 145 detects. The lines between the tank 100 and the High pressure pump 125 are referred to as a low pressure area.

Eine Steuerung 160 beinhaltet einen Druckregler und beaufschlagt die entsprechenden Stellelemente, wie beispielsweise die Spule 136 des Druckregelventils oder Druck-Abbau-Ventils 135 und/oder die Zumeßeinheit 122, mit Ansteuersignalen. Die Steuerung 160 verarbeitet verschiedene Signale verschiedener Sensoren 165 und 166, die den Betriebszustand der Brennkraftmaschine und/oder des Kraftfahrzeugs, das die Brennkraftmaschnine antreibt, charakterisieren. Ein solcher Betriebszustand ist beispielsweise die Drehzahl N der Brennkraftmaschine oder ein Temperaturwert.A controller 160 includes a pressure regulator and acts on the corresponding control elements, such as for example, coil 136 of the pressure control valve or pressure relief valve 135 and / or the metering unit 122, with Control signals. The controller 160 processes various Signals from various sensors 165 and 166 that the Operating state of the internal combustion engine and / or the Motor vehicle that drives the internal combustion engine characterize. Such an operating state is for example the speed N of the internal combustion engine or a Temperature value.

Besonders vorteilhaft ist es, wenn die Steuerung weitere oder andere Stellelemente ansteuert. Zur Regelung des Druckes P im Hochdruckbereich können alternativ und/oder zusätzlich weitere Stellelemente eingesetzt werden. Dies sind beispielsweise eine in der Fördermenge verstellbare elektrische Vorförderpumpe 110, eine steuerbare Hochdruckpumpe 125 und/oder ein elektrisch steuerbares Druckregelventil 140 im Niederdruckbereich.It is particularly advantageous if the control system has further or controls other control elements. To regulate the pressure P in High pressure areas can alternatively and / or additionally Control elements are used. For example, these are one adjustable electrical feed pump 110 a controllable high pressure pump 125 and / or an electric one controllable pressure control valve 140 in the low pressure range.

Diese Einrichtung arbeitet wie folgt: Der Kraftstoff, der sich im Vorratsbehälter befindet, wird von der Vorförderpumpe 110 durch die Filtermittel 105 und 115 gefördert. Ausgangsseitig der Vorförderpumpe 110 ist der Kraftstoff mit einem Druck von einigen bar beaufschlagt.This facility works as follows: The fuel that is is located in the reservoir, the feed pump 110 promoted by the filter means 105 and 115. Output side of the pre-feed pump 110 is the fuel with a pressure of some bar.

Wenn der Druck im Niederdruckbereich des Kraftstoffsystems einen vorgebbaren Druck erreicht hat, so öffnet das Niederdruckbegrenzungsventil 140 und gibt die Verbindung zwischen dem Ausgang der Vorförderpumpe 110 und dem Vorratsbehälter 100 frei. Mittels des Niederdruckbegrenzungsventils 140 wird der Druck im Niederdruckbereich auf Werte von ca. 5 bar gehalten.When the pressure in the low pressure area of the fuel system has reached a predefinable pressure, this opens Low pressure relief valve 140 and gives the connection between the output of the prefeed pump 110 and the Storage container 100 free. By means of the Low pressure relief valve 140 is the pressure in Low pressure range kept at values of approx. 5 bar.

Die Ausgestaltung des Niederdruckbereichs, insbesondere die Anordnung der Ventile und Filter ist nur beispielhaft dargestellt. Die Art, die Anordnung und/oder die Anzahl der Elemente kann auch unterschiedlich sein.The design of the low pressure area, in particular the Arrangement of the valves and filters is only an example shown. The type, arrangement and / or number of Items can also be different.

Die Hochdruckpumpe 125 fördert den Kraftstoff vom Niederdruckbereich in den Hochdruckbereich. Die Hochdruckpumpe 125 baut im Rail 130 einen sehr hohen Druck auf. Üblicherweise werden bei Systemen für fremdgezündete Brennkraftmaschinen Druckwerte von etwa 30 bis 100 bar und bei selbstzündenden Brennkraftmaschinen Druckwerte von etwa 1000 bis 2000 bar erzielt. Über die Injektoren 131 kann der Kraftstoff unter hohem Druck den einzelnen Zylindern der Brennkraftmaschine zugemessen werden. The high pressure pump 125 delivers the fuel from Low pressure area in the high pressure area. The high pressure pump 125 builds up a very high pressure in the Rail 130. Usually are in systems for spark ignition internal combustion engines Pressure values from about 30 to 100 bar and with auto-igniting Internal combustion engines pressure values from about 1000 to 2000 bar achieved. The fuel can be injected via the injectors 131 high pressure of the individual cylinders of the internal combustion engine be measured.

Mittels des Sensors 145 wird der Druck im Rail bzw. im gesamten Hochdruckbereich erfaßt. Der Druck wird über die Zumeßeinheit ZME 120 geregelt, die mit einer Spule 122 ansteuerbar ist und die die Fördermenge der Hochdruckpumpe 125 verstellen kann. Mittels des Druck-Abbau-Ventils 135, das mit einer Spule 136 ansteuerbar ist, kann der Druck im Hochdruckbereich schnell abgebaut werden.The pressure in the rail or in the whole is measured by means of the sensor 145 High pressure area detected. The pressure is on the metering unit ZME 120 regulated, which can be controlled with a coil 122 and which can adjust the delivery rate of the high pressure pump 125. By means of the pressure relief valve 135, which has a coil 136 can be controlled, the pressure in the high-pressure area can quickly be dismantled.

Als Vorförderpumpe 110 werden üblicherweise mechanische Vorförderpumpen eingesetzt. Es können aber auch Elektrokraftstoffpumpen mit einem Gleichstrom-Motor (DC-Motoren) oder einem elektrisch komutierten Gleichstrom-Motor (EC-Motoren) eingesetzt werden. Für höhere Fördermengen, die insbesondere bei Nutzkraftfahrzeugen erforderlich sind, können auch mehrere parallel geschaltete Vorförderpumpen eingesetzt werden. In diesem Fall werden wegen der höheren Lebensdauer und höheren Verfügbarkeit vorzugsweise EC-Motoren verwendet.Mechanical feed pumps 110 are usually used Prefeed pumps used. But it can also Electric fuel pumps with a direct current motor (DC motors) or an electrically commutated DC motor (EC motors) can be used. For higher flow rates, the can be required in particular in the case of commercial vehicles several pre-feed pumps connected in parallel were also used become. In this case, because of the longer life and higher availability preferably used EC motors.

Von der Hochdruckpumpe 125 wird die Fördermenge QP in das Rail 130 gefördert. Über das Druck-Abbau-Ventil 135 wird die Menge QDAV in den Niederdruckbereich abgelassen. Die Druckaufbaumenge QR steht für den Druckaufbau zur Verfügung. Über die Injektoren 131 gelangt die Zumessmenge QI zu den Injektoren 131. Die Menge QI setzt sich zusammen aus der eingespritzten Kraftstoffmenge QK, der Leckagemenge und einer Steuermenge der Injektoren. Die Leckagemenge und die Steuermenge gelangen wieder zurück in den Niederdruckbereich. Die eingespritzte Kraftstoffmenge gelangt in die Brennkraftmaschine.From the high pressure pump 125, the delivery rate QP is in the rail 130 funded. Via the pressure relief valve 135, the amount QDAV drained into the low pressure area. The amount of pressure build-up QR is available for pressure build-up. About the injectors 131, the metering quantity QI reaches the injectors 131. The quantity QI is made up of the amount of fuel injected QK, the amount of leakage and a control amount of the injectors. The Leakage amount and the tax amount get back into the Low pressure range. The amount of fuel injected arrives into the internal combustion engine.

Die Fig. 1 zeigt das typische Zeitverhalten für einen Öffnungs- und Schließvorgang des Druckabbauventils. Dabei stellt Δtein/aus die minimale Zeit dar, die vergeht von einem Öffnungs- und sofortigen Schließvorgang. Δtraster ist die Zeit die zum Abfragen des Öffnungs- und Schließvorgangs gehört. Dabei gelten die Bedingungen: Δtein/aus < Δtraster + Δtaus, sowie Δtaus < Δtraster 1 shows the typical time behavior for an opening and closing process of the pressure relief valve. Δtein / aus represents the minimum time that elapses between an opening and an immediate closing process. Δtraster is the time that is required to query the opening and closing process. The conditions apply: Δon / off <Δtraster + Δaus, as well Δout <Δtraster

Fig. 2 zeigt die Flußrate über der Druckdifferenz Δp. In Fig. 3 ist noch einmal veranschaulicht, wie die Zeiten und die Druckdifferenzen zusammenhängen. Über die beiden Gleichungen Q(Δp) DAV = Δti*A* (2/ρ)1/2Δp1/2 DAV Δp = Q(Δp)DAV/EpRail * VRail mit

Q(Δp)
= Absteuermenge durch das DAV
Δti
= Öffnungszeit DAV (tein/aus für Δpauf)
A
= Drosselquerschnitt DAV Δtaus für Δpzu
ρ
= Dichte Kraftstoff
Δp
= Druckdifferenz am DAV
Eo
= Elastizitätsmodul Kraftstoff (Funktion des Raildrucks)
VRail
= Railvolumen
p
= Druckabfall im Rail
ergibt sich eine parametrische Kennfeldschar für Δpauf und Δpzu gemäß Fig. 4. Gemäß Fig. 5 wird der Rail-Druck in einem Common-Rail-System mittels des Druck-Abbau-Ventils 135 von einer Spule und einer elektronischen Steuerung angesteuert, wobei das Druck-Abbau-Ventil 135 abhängig von der Regelabweichung pRail-psoll mit einer Hysteresekennlinie geöffnet oder geschlossen wird. Erfindungsgemäß sind die Hysteresegrenzen für den Öffnungs- und Schließvorgang des Druck-Abbau-Ventils 135 über ein Rechenschema, das in der elektronischen Steuerung abgelegt ist, variabel gestaltet. Die Hysteresegrenzen zum Öffnen und Schließen des Druck-Abbau-Ventils 135 sind als Kennfeldgrößen parametrisiert, wobei die obere Hysteresegrenze zum Öffnen des Druck-Abbau-Ventils 135 abhängig ist von einem ersten Kennfeld, bei dem die Ausgangsgröße Δpauf eine Funktion des Drucks pRail ist und wobei die untere Hysteresegrenze zum Schließen des Druckabbauventils 135 abhängig ist von einem zweiten Kennfeld, bei dem die Ausgangsgröße Δpzu eine Funktion des Raildrucks pRail ist.Fig. 2 shows the flow rate over the pressure difference Δp. 3 illustrates once again how the times and the pressure differences are related. About the two equations Q (Δp) DAV = Δt i * A * (2 / ρ) 1/2 Δp 1/2 DAV Δp = Q (Δp) DAV / E prail * V Rail With
Q (Δp)
= Tax amount by the DAV
Δt i
= Opening time DAV (t on / off for Δp on )
A
= Throttle cross section DAV Δt off for Δp too
ρ
= Density fuel
Δp
= Pressure difference at the DAV
Eo
= Modulus of elasticity of fuel (function of rail pressure)
V Rail
= Rail volume
p
= Pressure drop in the rail
results in a parametric map opener for Ap and Ap to as shown in FIG. 4. As shown in FIG. 5, the rail pressure in a common rail system by means of the pressure-reduction valve 135 is driven by a coil and an electronic controller, wherein the pressure release valve 135 is to be opened or closed with a hysteresis characteristic, depending on the control deviation p Rail -p. According to the invention, the hysteresis limits for the opening and closing process of the pressure reduction valve 135 are designed to be variable using a calculation scheme that is stored in the electronic control. The hysteresis limits for opening and closing the pressure relief valve 135 are parameterized as map parameters, the upper hysteresis limit for opening the pressure relief valve 135 being dependent on a first map, in which the output variable Δp depends on a function of the pressure p rail and the lower hysteresis limit for closing the pressure reduction valve 135 is dependent on a second characteristic map in which the output variable Δp is a function of the rail pressure p rail .

Das erste Kennfeld Δpauf (pRail) und das zweite Kennfeld Δpzu (pRail) sind durch die mathematisch-physikalischen Beziehungen so dimensioniert, daß Δpauf (pRail) die minimal darstellbare Druckdifferenz Δpauf für einen Öffnungs- und Schließvorgang des Druck-Abbau-Ventils darstellt und das zweite Kennfeld Δpzu (pRail) die minimal akzeptable Druckdifferenz Δpzu darstellt, wodurch sichergestellt ist, daß das Druck-Abbau-Ventil ohne Unterschwingen des Ist-Drucks schließbar ist. The first map Dp (p Rail) and the second map Dp to (p Rail) are dimensioned by the mathematical-physical relationships such that Dp (p Rail) the minimal displayable pressure difference Dp on for an opening and closing operation of the pressure Represents dismantling valve and the second characteristic diagram Δp zu (p Rail ) represents the minimally acceptable pressure difference Δp zu , which ensures that the pressure reducing valve can be closed without undershoot of the actual pressure.

BezugszeichenlisteReference list

100100
KraftstoffvorratsbehälterFuel tank
105105
erstes Filterfirst filter
110110
VorförderpumpePrefeed pump
115115
zweites Filtersecond filter
120120
VentilValve
122122
ZumeßeinheitMetering unit
125125
Hochdruckpumpehigh pressure pump
130130
RailRail
131131
InjektorenInjectors
135135
Druckregelventil oder Druck-Abbau-VentilPressure control valve or pressure relief valve
136136
SpuleKitchen sink
140140
NiederdruckbegrenzungsventilLow pressure relief valve
145145
Sensorsensor
160160
Steuerungcontrol
165165
SensorenSensors
166166
SensorenSensors

Claims (6)

Verfahren zur Regelung des Rail-Drucks in einem Common-Rail-System für eine Brennkraftmaschine mittels eines Druck-Abbau-Ventils, das von einer elektronischen Steuerung angesteuert ist, wobei das Druck-Abbau-Ventil abhängig von einer Regelabweichung (pRail - psoll) ansteuerbar ist, dadurch gekennzeichnet, daß die Hysteresegrenzen (Δpauf, Δpzu) für den Öffnungs- und Schließvorgang des Druck-Abbau-Ventils variabel vorgebbar sind.A method of controlling the rail pressure in a common rail system for an internal combustion engine by means of a pressure-reducing valve which is driven by an electronic controller, wherein said pressure-reducing valve depending on a control deviation (p Rail - to p , can be controlled), characterized in that the hysteresis (Dp on, to Ap) for the opening and closing operation of the pressure-reducing valve are variably predetermined. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß wenigstens eine der Hysteresegrenzen (Δpauf, Δpzu) abhängig vom Raildruck (pRail) vorgebbar sind.A method according to claim 1, characterized in that at least one of hysteresis (Dp on, to Dp) are dependent on the rail pressure (p Rail) predetermined. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß eine obere Hysteresegrenze (Δpzu) zum Schließen des Druck-Abbau-Ventils in einem ersten Kennfeld als Funktion des Raildrucks (pRail) abgelegt ist.The method of claim 1 or 2, characterized in that an upper hysteresis limit (Dp to) is stored for closing the pressure reducing valve in a first characteristics map as a function of the rail pressure (p Rail). Verfahren nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, daß eine zweite Hysteresegrenze (Δpauf) zum Öffnen des Druck-Abbau-Ventils in einem zweiten Kennfeld als Funktion des Raildrucks (pRail) abgelegt ist. Method according to one of the preceding claims, characterized in that a second hysteresis (Dp on) for opening the pressure-reducing valve in a second map as a function of the rail pressure (p Rail) is stored. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das zweite Kennfeld (Δpauf (pRail)) und das erste Kennfeld (Δpzu (prail)) als eine mathematisch physikalische Beziehung im Steuergerät abgelegt ist, wobei die Beziehungen gelten Q(Δp)DAV = Δti * A (2/ρ)1/2*(Δp)1/2 Δp = Q (Δp) /ERail * VRail mit
Q(Δp)
= Absteuermenge durch das DAV
Δti
= Öffnungszeit DAV Δtein/aus für Δpauf
A
= Drosselquerschnitt DAV Δtaus für Δpzu
ρ
= Dichte Kraftstoff
ΔpDAV
= Druckdifferenz am DAV
ERail
= Elastizitätsmodul Kraftstoff (Funktion Raildruck, Temperatur)
VRail
= Railvolumen
Method according to Claim 1 or 2, characterized in that the second characteristic diagram (Δp on (p Rail )) and the first characteristic diagram (Δp on (prail)) are stored in the control unit as a mathematically physical relationship, the relationships being valid Q (Δp) DAV = Δt i * A (2 / ρ) 1/2 * (Δp) 1/2 Δp = Q (Δp) / E Rail * V Rail With
Q (Δp)
= Tax amount by the DAV
Δt i
= Opening time DAV Δon / off for Δpauf
A
= Throttle cross section DAV Δtaus for Δpzu
ρ
= Density fuel
Δp DAV
= Pressure difference at the DAV
E Rail
= Fuel elasticity module (rail pressure function, temperature)
V Rail
= Rail volume
Verfahren nach einem der vorherigen Ansprüche, dadurch gekennzeichnet, daß das erste Kennfeld (Δpauf(pRail)) und das zweite Kennfeld (Δpzu(pRail)) so dimensioniert sind, daß Δpauf(pRail) die minimal darstellbare Druckdifferenz (Δpauf) für einen Öffnungs- und Schließvorgang des Druck-Abbau-Ventils darstellt und das zweite Kennfeld (Δpzu(pRail)) die minimal akzeptabel Druckdifferenz (Δpzu) darstellt, wodurch sichergestellt ist, daß das Druck-Abbau-Ventil ohne Unterschwingen des Ist-Drucks schließbar ist.Method according to one of the preceding claims, characterized in that the first characteristic diagram (Δp on (p rail )) and the second characteristic diagram (Δp on (p rail )) are dimensioned such that Δp on (p rail ) is the minimally representable pressure difference ( Represents Δp on ) for an opening and closing process of the pressure reduction valve and the second map (Δp to (p Rail )) represents the minimum acceptable pressure difference (Δp to ), which ensures that the pressure reduction valve without Undershoot of the actual pressure is closable.
EP00108928A 1999-09-30 2000-04-27 Method to decrease the pressure in the common rail of an internal combustion engine Withdrawn EP1088981A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19946908 1999-09-30
DE1999146908 DE19946908A1 (en) 1999-09-30 1999-09-30 Process for reducing the rail pressure in a common rail system for internal combustion engines

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Publication Number Publication Date
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EP1088981A3 EP1088981A3 (en) 2002-09-11

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EP1298306A2 (en) * 2001-09-28 2003-04-02 Robert Bosch Gmbh Method of operating a combustion engine
FR2862092A1 (en) * 2003-11-07 2005-05-13 Bosch Gmbh Robert Internal combustion engine controlling process, involves activating pre-control block for controlling pressure control valve when regulated pressure of common fuel ramp is lower than preset pressure
US7848868B2 (en) 2006-09-05 2010-12-07 Denso Corporation Method and apparatus for pressure reducing valve to reduce fuel pressure in a common rail
EP2085596A3 (en) * 2008-01-30 2016-03-16 Hitachi, Ltd. Fuel injector for internal combustion engine
DE102006035312B4 (en) 2005-12-27 2019-02-07 Denso Corporation Krafstoffeinspritzsteuereinrichtung
WO2020165333A1 (en) * 2019-02-14 2020-08-20 Mtu Friedrichshafen Gmbh Method for operating an injection system of an internal combustion engine, an injection system for an internal combustion engine, and an internal combustion engine comprising such an injection system

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DE102015205586B3 (en) * 2015-03-27 2016-04-07 Continental Automotive Gmbh High-pressure injection device for an internal combustion engine

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DE19548278A1 (en) 1995-12-22 1997-06-26 Bosch Gmbh Robert Method of managing IC engine with high pressure fuel injection esp engine with common-rail system
DE19731994A1 (en) 1997-07-25 1999-01-28 Bosch Gmbh Robert Method and device for controlling an internal combustion engine

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DE19607070B4 (en) * 1996-02-24 2013-04-25 Robert Bosch Gmbh Method and device for controlling an internal combustion engine
JPH1054318A (en) * 1996-08-09 1998-02-24 Denso Corp Accumulator type fuel supply device for engine

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Publication number Priority date Publication date Assignee Title
DE19548278A1 (en) 1995-12-22 1997-06-26 Bosch Gmbh Robert Method of managing IC engine with high pressure fuel injection esp engine with common-rail system
DE19731994A1 (en) 1997-07-25 1999-01-28 Bosch Gmbh Robert Method and device for controlling an internal combustion engine

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1298306A2 (en) * 2001-09-28 2003-04-02 Robert Bosch Gmbh Method of operating a combustion engine
EP1298306A3 (en) * 2001-09-28 2004-11-10 Robert Bosch Gmbh Method of operating a combustion engine
FR2862092A1 (en) * 2003-11-07 2005-05-13 Bosch Gmbh Robert Internal combustion engine controlling process, involves activating pre-control block for controlling pressure control valve when regulated pressure of common fuel ramp is lower than preset pressure
DE102006035312B4 (en) 2005-12-27 2019-02-07 Denso Corporation Krafstoffeinspritzsteuereinrichtung
US7848868B2 (en) 2006-09-05 2010-12-07 Denso Corporation Method and apparatus for pressure reducing valve to reduce fuel pressure in a common rail
EP2085596A3 (en) * 2008-01-30 2016-03-16 Hitachi, Ltd. Fuel injector for internal combustion engine
WO2020165333A1 (en) * 2019-02-14 2020-08-20 Mtu Friedrichshafen Gmbh Method for operating an injection system of an internal combustion engine, an injection system for an internal combustion engine, and an internal combustion engine comprising such an injection system
CN113874615A (en) * 2019-02-14 2021-12-31 罗尔斯·罗伊斯解决方案有限公司 Method for operating an injection system of an internal combustion engine, injection system for an internal combustion engine, and internal combustion engine having such an injection system
US11408365B2 (en) 2019-02-14 2022-08-09 Rolls-Royce Solutions GmbH Method for operating an injection system of an internal combustion engine, an injection system for an internal combustion engine, and an internal combustion engine including an injection system

Also Published As

Publication number Publication date
JP2001115884A (en) 2001-04-24
EP1088981A3 (en) 2002-09-11
DE19946908A1 (en) 2001-04-05

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