EP1519026B1 - Method and device for controlling a valve and method and device for controlling pump-nozzle unit with a valve - Google Patents

Method and device for controlling a valve and method and device for controlling pump-nozzle unit with a valve Download PDF

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Publication number
EP1519026B1
EP1519026B1 EP20040022133 EP04022133A EP1519026B1 EP 1519026 B1 EP1519026 B1 EP 1519026B1 EP 20040022133 EP20040022133 EP 20040022133 EP 04022133 A EP04022133 A EP 04022133A EP 1519026 B1 EP1519026 B1 EP 1519026B1
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EP
European Patent Office
Prior art keywords
valve
time
valve seat
signal
seat
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 - Fee Related
Application number
EP20040022133
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German (de)
French (fr)
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EP1519026A2 (en
EP1519026A3 (en
Inventor
Jörg Dr. Beilharz
Maximilian Dr. Kronberger
Richard Pirkl
Christian Rissler
Hans-Jörg Wiehoff
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Continental Mechanical Components GmbH and Co KG
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Continental Automotive GmbH
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Publication date
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Publication of EP1519026A2 publication Critical patent/EP1519026A2/en
Publication of EP1519026A3 publication Critical patent/EP1519026A3/en
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Publication of EP1519026B1 publication Critical patent/EP1519026B1/en
Expired - Fee Related legal-status Critical Current
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Classifications

    • 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
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators
    • 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
    • F02D41/20—Output circuits, e.g. for controlling currents in command coils
    • F02D41/2096—Output circuits, e.g. for controlling currents in command coils for controlling piezoelectric injectors
    • 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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • 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
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366—Valves being actuated electrically
    • 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
    • F02D41/20—Output circuits, e.g. for controlling currents in command coils
    • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
    • F02D2041/2055—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit with means for determining actual opening or closing time
    • 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
    • F02D41/20—Output circuits, e.g. for controlling currents in command coils
    • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
    • F02D2041/2065—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit the control being related to the coil temperature

Definitions

  • the invention relates to a method and a device for controlling a valve. It further relates to a method and apparatus for controlling a pump-nozzle device with a valve.
  • the valve has a valve drive, which is designed as a piezoelectric actuator, a valve member, a valve body and a valve seat.
  • a pump-nozzle device is used in particular for supplying fuel into a combustion chamber of a cylinder of an internal combustion engine, in particular a diesel internal combustion engine.
  • a pump, a control unit with the valve and a nozzle unit form a structural unit.
  • the drive of a piston of the pump is preferably via a camshaft of an internal combustion engine by means of a rocker arm.
  • the pump can be hydraulically coupled via the valve to a low-pressure fuel supply device. It is hydraulically coupled on the output side with the nozzle unit. Start of injection and injection quantity are determined by the valve and its valve drive. Due to the compact design of the pump-nozzle device results in a very low volume of high pressure and high hydraulic stiffness. This enables very high injection pressures of around 2,000 bar. This high injection pressure in conjunction with the good controllability of the start of injection and the injection quantity allow a significant reduction in emissions while low fuel consumption when using the internal combustion engines.
  • a pump-nozzle device is known with a pump and a valve with a valve member, the hydraulic coupling of a Ab horrraums with a Flow channel controls.
  • the drainage channel is hydraulically coupled to the pump and a nozzle unit.
  • An inlet channel is provided, which is hydraulically coupled to the Ab horrraum.
  • the valve member is associated with a piezoelectric valve drive, via which the valve member can be adjusted between two end positions. In a first end position of the valve member of the flow channel is hydraulically coupled to a Ab tenuraum and this in turn with the inlet channel. In a second end position of the valve member of the drainage channel is hydraulically decoupled from the Abberichtraum and the valve member is in a valve seat of the valve.
  • the end of injection is determined by controlling the valve member to its first end position by means of the actuator and thus allowing fluid to flow back into the discharge chamber and the inlet channel via the discharge channel, with the result that the pressure in the pump and thus also in the nozzle unit decreases, which in turn leads to a closing of the nozzle unit.
  • a precise metering of fuel through the pump-nozzle device requires a very precise controllability of the valve.
  • a valve is known with an actuator driven by a piezoelectric actuator.
  • the piezoelectric actuator is used simultaneously as a pressure sensor.
  • the voltage of the piezoelectric actuator is evaluated so that a voltage change occurs and this is detected as a detection signal.
  • Information about the time at which the valve member actually lifts off its valve seat and the pressure in a control chamber begins to decrease is derived from the detection signal.
  • the invention is characterized by a method for controlling a valve with a valve drive, which is designed as a piezoelectric actuator, a valve member, a valve body and a valve seat.
  • a valve drive which is designed as a piezoelectric actuator, a valve member, a valve body and a valve seat.
  • the valve member is controlled from a position away from the valve seat into the valve seat.
  • a signal characterizing the piezo voltage is detected.
  • At least the first derivative of the signal characterizing the piezoelectric voltage is then determined.
  • the time of impact of the valve member on the valve seat is detected when the at least first derivative of the signal exceeds a predetermined threshold.
  • a closing time is determined depending on the predefinable time and the time of impact.
  • the actuation of the valve drive then takes place depending on the closing time.
  • the valve of a pump-nozzle device is controlled accordingly.
  • the pump-nozzle apparatus has a pump having a piston and a working space, a control unit including a drain channel hydraulically coupled to the working space, and a valve having a valve actuator configured as a piezoactuator, a valve member, a valve body a valve seat and a spillway which is hydraulically decoupled from the drain passage when the valve member abuts the valve seat and which is otherwise coupled to the drain passage.
  • piezoelectric voltage such as the capacitance of the piezoelectric actuator or the current applied to the piezoactuator, or the charge of the piezoactuator or the electrical energy of the piezoactuator piezoelectric actuator.
  • the at least first derivative of the signal is monitored only within a predetermined time window to an expected time of impact on exceeding the predetermined threshold. This has the advantage of less computational effort and at the same time a lower probability a misjudgment of the time of impact due to noise.
  • the piezoelectric voltage characterizing signal is squared and then determined at least the first derivative of the squared signal. This is based on the knowledge that the signal characterizing the piezoelectric voltage has a substantially root-shaped profile and that, thus, the signal can be linearized by squaring and a higher signal-to-noise ratio can be easily achieved.
  • the second derivative of the squared signal is determined. This has the advantage that the characteristic kink of the original signal can then be recognized particularly well and easily.
  • the closing time period is determined several times and subjected to filtering. This has the advantage that such a very reliable value of the closing period can be determined.
  • a drive time of the valve drive depends on the closing time period and a set value of the closing time period corrected.
  • the predeterminable time at which the valve member is controlled from a position away from the valve seat into the valve seat is selected so that the piston of the pump in its Top dead center is and remains until the expected impact of the valve member on the valve seat.
  • the pump-nozzle device ( FIG. 1 ) comprises a pump unit, a control unit and a nozzle unit.
  • the pump-nozzle device is preferably used for supplying fuel into the combustion chamber of a cylinder of an internal combustion engine.
  • the internal combustion engine is preferably designed as a diesel engine.
  • the internal combustion engine has an intake tract for intake of air, which can be coupled by means of gas inlet valves with cylinders.
  • the internal combustion engine also has an exhaust tract, which discharges the gases to be discharged from the cylinders via the outlet valve.
  • the cylinders are each assigned pistons, which are each coupled via a connecting rod with a crankshaft.
  • the crankshaft is coupled to a camshaft.
  • the pump unit comprises a piston 11, a pump body 12, a working space 13 and a pump return means 14, which is preferably designed as a spring.
  • the piston 11 is coupled in the installed state in an internal combustion engine with a camshaft 16, preferably by means of a rocker arm, and is driven by this.
  • the piston 11 is guided in a recess of the pump body 12 and determined depending on its position, the volume of the working space 13.
  • the pump return means 14 is formed and arranged so that the limited volume of the piston 11 through the working space 13 has a maximum value when acting on the piston 11 no external forces, ie forces that are transmitted via the coupling with the camshaft 16.
  • the nozzle needle 53 abuts a needle seat 54 and thus closes a nozzle 56, which is provided for supplying the fuel into the combustion chamber of the cylinder of the internal combustion engine.
  • the nozzle unit is preferably, as shown, formed as an inwardly opening nozzle unit.
  • the nozzle needle 53 is slightly spaced from the needle seat 54 toward the nozzle return means 52, thus releasing the nozzle 56.
  • fuel is metered into the combustion chamber of the cylinder of the internal combustion engine.
  • the first or second state is assumed depending on a balance of forces from the force acting on the nozzle needle 53 by the nozzle return means 52 and the counteracting force which is caused by the hydraulic pressure in the region of the needle heel 57.
  • the control unit comprises an inlet channel 21 and an outlet channel 22.
  • the inlet channel 21 and the outlet channel 22 can be hydraulically coupled by means of a valve.
  • the inlet channel 21 is guided from a low-pressure side connection of the pump-nozzle device to the valve.
  • the drain passage 22 is hydraulically coupled to the working space 13 and is guided to the needle heel 57 and is hydraulically with the Nozzle 56 can be coupled depending on the condition occupied by the nozzle needle 53.
  • the valve comprises a valve member 231, which is preferably designed as a so-called.
  • a valve d. H. it opens outward against the flow direction of the fluid.
  • the valve further comprises a Abêtraum 232 which is hydraulically coupled to the inlet channel 21 and by means of the valve member 231 with a high-pressure chamber is hydraulically coupled.
  • the high-pressure chamber is hydraulically coupled to the drainage channel 22.
  • valve return means is provided, which is arranged and formed so that it the valve member 231 in an open position, d. H. spaced apart from the valve seat 234 when the forces acting on the valve member by an actuator 24 are less than the forces acting on the valve member 231 by the valve return means.
  • the actuator 24 is formed as a piezo stack.
  • a device 60 for controlling the pump-nozzle device is provided, which generates corresponding actuating signals for the valve.
  • valve member 231 In the open position of the valve member 231 is sucked in a movement of the piston 11, which is directed upward, ie in the direction away from the nozzle 56, fuel via the inlet channel 21 to the working space 13. As long as the valve member 231 during a subsequent downward movement of the piston 11, ie in a directed towards the nozzle 56 movement, is still in its open position, located in the working chamber 13 and the drain passage 22 fuel through the valve back into the Ab bruiseraum 232 and possibly pushed back into the inlet channel 21.
  • valve member 231 when the valve member 231 is controlled in its closed position during the downward movement of the piston 11, the fuel in the working chamber 13 and thus in the flow passage 22 and in the high-pressure chamber 233 is compressed, whereby the pressure with increasing downward movement of the piston 11 in the Working space 13, in the high-pressure chamber 233 and in the drain passage 22 increases.
  • the force caused by the hydraulic pressure increases, which acts on the needle shoulder 57 in the direction of an opening movement of the nozzle needle 53 to release the nozzle 56.
  • the nozzle needle 53 moves away from the needle seat 54, thus giving the nozzle 56 for the fuel supply to the cylinder of the internal combustion engine free.
  • the nozzle needle 53 then moves back into the needle seat 54 and thus closes the nozzle 56 when the hydraulic pressure in the drain passage 22 falls below the value at which the force caused by the hydraulic pressure at the needle heel 57 is smaller than that caused by the nozzle return means 52 Force.
  • the time at which this value is exceeded and at which thus the fuel metering is terminated, can be influenced by the control of the valve member 231 from its closed position to an open position.
  • the valve member By controlling the valve member from its closed position to its open position, the hydraulic coupling between the high-pressure chamber and the Abêtraum 232 and the inlet channel 21 produced. Due to the high pressure difference prevailing during opening between the fluid in the high-pressure space and the outlet channel 22 and the fluid in the discharge space 232 and the inlet channel 21, the fuel then flows from the high-pressure space into the discharge space 232 at very high speed, generally at the speed of sound and further into the inlet channel 21. As a result, the pressure in the high-pressure chamber and the outlet channel 22 is then rapidly reduced so much that the forces acting on the nozzle needle 53 by the nozzle return means 52 cause the nozzle needle 53 to move into the needle seat 54 and Thus then the nozzle 56 closes.
  • the valve member is controlled from a position away from the valve seat 234 into the valve seat 234.
  • the predetermined time is preferably chosen so that the piston is in its top dead center and remains until the expected impact of the valve member 231 on the valve seat 234. However, it can also be selected within a time range in which the piston is not in its upper Dead center is located.
  • the piezo voltage V_INJ which can assume values up to approximately 150 V, is transformed by means of a voltage divider into a predetermined voltage range and optionally subsequently filtered. Subsequently, an analog-to-digital conversion of the signal takes place by means of a so-called sample-and-hold analog-to-digital converter with a very short sampling time of a few ⁇ sec.
  • the digital voltage values thus obtained are preferably temporarily stored and processed further only after an expected impingement of the valve member 231 on its valve seat 234. Due to the known sampling rate of the analog-to-digital converter, a time assignment of the individual sampled values is then also possible.
  • the sampled piezo voltage V_INJ is still preferably interpolated, whereby a higher temporal resolution of the signal curve of the piezo voltage V_INJ can be achieved. This is preferably done by means of a finite impulse response (FIR) filter.
  • FIR finite impulse response
  • the piezo voltage V_INJ is squared. This corresponds to a linearization of the course of the piezoelectric voltage V_INJ, since this has a substantially root-shaped course. Alternatively, however, can be dispensed with the squaring, which is indicated by the dashed arrow.
  • a block B7 the first derivative of the signal curve of the piezo voltage V_INJ is then determined. There is thus a differentiation according to the time.
  • a second derivative of the signal curve of the piezo voltage V_INJ can be determined.
  • a block B11 only the values of the derived piezo voltage V_INJ are selected, which were detected within a predetermined time window by the expected time of impact of the valve member 231 on the valve seat 234.
  • the time window is preferably predetermined so that all known variations of the closing time period are taken into account.
  • a block B15 it is then made plausible whether the closing time period T_CL is less than a predetermined second threshold value or greater than a predetermined third threshold value SW3.
  • the second and third thresholds SW2, SW3 are selected so that falling below or exceeding is possible only in the case of a fault of the valve. Accordingly, a failure of the valve in block B15 is then diagnosed.
  • a first correction value T_CL_COR1 is determined as a function of a temperature TEMP which is characteristic for the temperature of the valve drive 24 and thus of the piezoactuator and an energy E supplied to the valve drive 24 and dependent on a setpoint value T_CL_SP of the closing time duration.
  • the first correction value T_CL_COR1 is an estimated value of the change of the closing time duration depending on the temperature TEMP and the supplied electric energy E.
  • the closing time period T_CL_SP is preferably given for predetermined operating conditions, ie for a predetermined temperature TEMP and supplied electric energy E. Er preferably determined for the prevailing during operation of the valve drive 24 in the average temperature TEMP and the electrical energy supplied to it on average.
  • the block B19 accordingly contains a corresponding model, by means of which the first correction value T_CL_COR1 is then determined.
  • a correction value T_SOI_OFS for the activation time T_SOI is then determined, preferably by forming the sum of the first and second correction values T_CL_COR1, T_CL_COR2.
  • a block B25 then becomes dependent on the correction value T_SOI_OFS for the drive time T_SOI and a requested time at which the valve member 231 on its valve seat 234, the triggering time T_SOI determined.
  • FIGS. 4a to 4d show gradients plotted over time t.
  • FIG. 4a shows the time course of the squared piezo voltage V_INJ.
  • FIG. 4b shows the stroke CTRL_VL of the valve member 231.
  • Figure 4c shows the course of the pressure P_H in the working space 13 of the pump.
  • FIG. 4d shows the time course of the metered with the pump-nozzle device amount of fuel MFF.
  • T_SOI the valve drive 24 is subjected to voltage, the piezo voltage V_INJ.
  • the valve member 231 impinges on the valve seat 234.
  • the slope of the substantially linear curve of the squared piezo voltage V_INJ then increases suddenly at the instant t1.
  • the pressure P_H in the working space 13 of the pump begins to increase from time t1.
  • time t2 the pressure required to open the nozzle needle 53 is reached and the injection process begins.
  • the determination of the closing period takes place during a period during which the piston 11 is in its upper dead center. This then has the consequence that the course of the pressure P_H in the working space 13 is substantially constant, namely at low pressure level with the result that the metered amount of fuel MFF according to Figure 4c is zero.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Reciprocating Pumps (AREA)

Description

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zum Steuern eines Ventils. Sie betrifft ferner ein Verfahren und eine Vorrichtung zum Steuern einer Pumpe-Düse-Vorrichtung mit einem Ventil. Das Ventil hat einen Ventilantrieb, der als Piezoaktor ausgebildet ist, ein Ventilglied, einen Ventilkörper und einen Ventilsitz. Eine Pumpe-Düse-Vorrichtung wird insbesondere zur Kraftstoffzufuhr in einen Brennraum eines Zylinders einer Brennkraftmaschine, insbesondere einer Diesel-Brennkraftmaschine, eingesetzt. Bei einer Pumpe-Düse-Vorrichtung bilden eine Pumpe, eine Steuereinheit mit dem Ventil und eine Düseneinheit eine Baueinheit. Der Antrieb eines Kolbens der Pumpe erfolgt vorzugsweise über eine Nockenwelle einer Brennkraftmaschine mittels eines Kipphebels.The invention relates to a method and a device for controlling a valve. It further relates to a method and apparatus for controlling a pump-nozzle device with a valve. The valve has a valve drive, which is designed as a piezoelectric actuator, a valve member, a valve body and a valve seat. A pump-nozzle device is used in particular for supplying fuel into a combustion chamber of a cylinder of an internal combustion engine, in particular a diesel internal combustion engine. In a pump-nozzle device, a pump, a control unit with the valve and a nozzle unit form a structural unit. The drive of a piston of the pump is preferably via a camshaft of an internal combustion engine by means of a rocker arm.

Die Pumpe ist über das Ventil an eine Niederdruck-Kraftstoffzuführeinrichtung hydraulisch koppelbar. Sie ist ausgangsseitig mit der Düseneinheit hydraulisch gekoppelt. Einspritzbeginn und Einspritzmenge werden durch das Ventil und dessen Ventilantrieb bestimmt. Durch die kompakte Bauweise der Pumpe-Düse-Vorrichtung ergibt sich ein sehr geringes Hochdruckvolumen und eine große hydraulische Steifigkeit. Es werden so sehr hohe Einspritzdrücke von zirka 2.000 bar ermöglicht. Dieser hohe Einspritzdruck in Verbindung mit der guten Steuerbarkeit des Einspritzbeginns und der Einspritzmenge ermöglichen eine deutliche Reduktion der Emissionen bei gleichzeitig niedrigen Kraftstoffverbrauch beim Einsatz der Brennkraftmaschinen.The pump can be hydraulically coupled via the valve to a low-pressure fuel supply device. It is hydraulically coupled on the output side with the nozzle unit. Start of injection and injection quantity are determined by the valve and its valve drive. Due to the compact design of the pump-nozzle device results in a very low volume of high pressure and high hydraulic stiffness. This enables very high injection pressures of around 2,000 bar. This high injection pressure in conjunction with the good controllability of the start of injection and the injection quantity allow a significant reduction in emissions while low fuel consumption when using the internal combustion engines.

Aus der DE 198 35 494 C2 ist eine Pumpe-Düse-Vorrichtung bekannt mit einer Pumpe und einem Ventil mit einem Ventilglied, das die hydraulische Kopplung eines Absteuerraums mit einem Ablaufkanal steuert. Der Ablaufkanal ist hydraulisch gekoppelt mit der Pumpe und einer Düseneinheit. Ein Zulaufkanal ist vorgesehen, der hydraulisch gekoppelt ist mit dem Absteuerraum. Dem Ventilglied ist ein piezoelektrischer Ventilantrieb zugeordnet, über den das Ventilglied zwischen zwei Endstellungen verstellt werden kann. In einer ersten Endstellung des Ventilglieds ist der Ablaufkanal hydraulisch gekoppelt mit einem Absteuerraum und dieser wiederum mit dem Zulaufkanal. In einer zweiten Endstellung des Ventilglieds ist der Ablaufkanal hydraulisch entkoppelt von dem Absteuerraum und das Ventilglied ist in einem Ventilsitz des Ventils.From the DE 198 35 494 C2 a pump-nozzle device is known with a pump and a valve with a valve member, the hydraulic coupling of a Absteuerraums with a Flow channel controls. The drainage channel is hydraulically coupled to the pump and a nozzle unit. An inlet channel is provided, which is hydraulically coupled to the Absteuerraum. The valve member is associated with a piezoelectric valve drive, via which the valve member can be adjusted between two end positions. In a first end position of the valve member of the flow channel is hydraulically coupled to a Absteuerraum and this in turn with the inlet channel. In a second end position of the valve member of the drainage channel is hydraulically decoupled from the Absteuerraum and the valve member is in a valve seat of the valve.

In der ersten Endstellung des Ventilglieds wird während eines Förderhubs der Pumpe Fluid von dem Zulaufkanal über den Absteuerraum und den Ablaufkanal von der Pumpe angesaugt. Während eines Arbeitshubs eines Pumpenkolbens der Pumpe wird in der ersten Endposition des Ventilglieds Fluid von der Pumpe über den Zulaufkanal, den Absteuerraum in den Ablaufkanal zurückgedrückt. In der zweiten Endstellung des Ventilglieds kann während des Förderhubs des Pumpenkolbens wegen der fehlenden hydraulischen Kopplung des Ablaufkanals mit dem Absteuerraum und dem Ablaufkanal kein Fluid zurückgedrückt werden und der Pumpenkolben erzeugt Hochdruck. Mit Überschreiten einer vorgegebenen Druckschwelle öffnet eine Düsennadel der Düseneinheit eine Düse der Düseneinheit und es erfolgt eine Einspritzung des Fluids. Das Einspritzende wird dadurch bestimmt, dass das Ventilglied mittels des Stellantriebs in seine erste Endposition gesteuert wird und so Fluid über den Ablaufkanal in den Absteuerraum und den Zulaufkanal zurückströmen kann, was zur Folge hat, dass der Druck in der Pumpe und somit auch in der Düseneinheit abnimmt, was wiederum zu einem Schließen der Düseneinheit führt.In the first end position of the valve member during a delivery stroke of the pump fluid is sucked from the inlet channel via the Absteuerraum and the drainage passage of the pump. During a working stroke of a pump piston of the pump in the first end position of the valve member fluid from the pump via the inlet channel, the spill chamber is pushed back into the drain channel. In the second end position of the valve member can be pushed back during the delivery stroke of the pump piston because of the lack of hydraulic coupling of the drain channel with the Absteuerraum and the drain channel no fluid and the pump piston generates high pressure. When a predetermined pressure threshold is exceeded, a nozzle needle of the nozzle unit opens a nozzle of the nozzle unit and there is an injection of the fluid. The end of injection is determined by controlling the valve member to its first end position by means of the actuator and thus allowing fluid to flow back into the discharge chamber and the inlet channel via the discharge channel, with the result that the pressure in the pump and thus also in the nozzle unit decreases, which in turn leads to a closing of the nozzle unit.

Ein präzises Zumessen von Kraftstoff durch die Pumpe-Düse-Vorrichtung setzt eine sehr präzise Ansteuerbarkeit des Ventils voraus.A precise metering of fuel through the pump-nozzle device requires a very precise controllability of the valve.

Aus der DE 100 24 662 A1 ist ein Ventil bekannt mit einem Stellglied, das von einem piezoelektrischen Aktor angetrieben wird. Der piezoelektrische Aktor wird gleichzeitig als Drucksensor verwendet. Die Spannung des piezoelektrischen Aktors wird dahingehend ausgewertet, dass eine Spannungsänderung auftritt und diese als Detektionssignal erfasst wird. Aus dem Detektionssignal wird eine Information darüber abgeleitet, zu welchem Zeitpunkt das Ventilglied tatsächlich von seinem Ventilsitz abhebt und der Druck in einem Steuerraum zu sinken beginnt.From the DE 100 24 662 A1 For example, a valve is known with an actuator driven by a piezoelectric actuator. The piezoelectric actuator is used simultaneously as a pressure sensor. The voltage of the piezoelectric actuator is evaluated so that a voltage change occurs and this is detected as a detection signal. Information about the time at which the valve member actually lifts off its valve seat and the pressure in a control chamber begins to decrease is derived from the detection signal.

Die DE 101 46 747 A1 beschreibt eine Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine mit einem durch einen piezoelektrischen Aktor betätigten Steuerventil. Zur Erkennung, ob ein Steuerventil seine Schließposition erreicht hat, wird nach erfolgtem Ladevorgang für eine vorgebbare Zeitdauer eines Messfensters an die Anschlüsse des Aktors eine Spannungsmesseinrichtung angeschlossen. In einem der Spannungsmesseinrichtung zugeordneten Differenzierglied wird die zeitliche Ableitung der Spannung zwischen den Anschlüssen gebildet. Es wird das Auftreten eines Nulldurchgangs in der zeitlichen Ableitung der Spannung überprüft, der den Zeitpunkt identifiziert, zu dem das Steuerventilglied seine Schließposition erreicht hat. Aus dem ermittelten Zeitpunkt des Erreichens der Schließposition des Steuerventilglieds wird ein Korrekturwert für den Ansteuerzeitpunkt des Ladevorgangs abgeleitet.The DE 101 46 747 A1 describes a fuel injector for an internal combustion engine having a control valve actuated by a piezoelectric actuator. In order to detect whether a control valve has reached its closed position, a voltage measuring device is connected to the terminals of the actuator for a predefinable period of time of a measurement window after completion of the charging process. In a differentiator element associated with the voltage measuring device, the time derivative of the voltage between the terminals is formed. It verifies the occurrence of a zero crossing in the time derivative of the voltage, which identifies the time at which the control valve member has reached its closed position. From the determined time of reaching the closed position of the control valve member, a correction value for the driving time of the charging process is derived.

Die Aufgabe der Erfindung ist es, ein Verfahren und eine Vorrichtung zum Steuern eines Ventils oder einer Pumpe-Düse-Vorrichtung mit dem Ventil zu schaffen, das bzw. die ein präzises Ansteuern des Ventils gewährleistet.The object of the invention is to provide a method and a device for controlling a valve or a pump-nozzle device with the valve, which ensures a precise driving of the valve.

Die Aufgabe wird gelöst durch die Merkmale der unabhängigen Patentansprüche. Vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen gekennzeichnet.The object is solved by the features of the independent claims. Advantageous embodiments of the invention are characterized in the subclaims.

Die Erfindung zeichnet sich aus durch ein Verfahren zum Steuern eines Ventils mit einem Ventilantrieb, der als Piezoaktor ausgebildet ist, einem Ventilglied, einem Ventilkörper und einem Ventilsitz. Zu einem vorgebbaren Zeitpunkt wird das Ventilglied von einer Position entfernt von dem Ventilsitz in den Ventilsitz gesteuert. Während das Ventilglied von der Position entfernt von dem Ventilsitz in den Ventilsitz gesteuert wird, wird ein die Piezospannung charakterisierendes Signal erfasst. Mindestens die erste Ableitung des die Piezospannung charakterisierenden Signals wird dann ermittelt. Der Zeitpunkt des Auftreffens des Ventilglieds auf den Ventilsitz wird erkannt, wenn die mindestens erste Ableitung des Signals einen vorgegebenen Schwellenwert überschreitet. Eine Schließzeitdauer wird abhängig von dem vorgebbaren Zeitpunkt und dem Zeitpunkt des Auftreffens ermittelt. Die Ansteuerung des Ventilantriebs erfolgt dann abhängig von der Schließzeitdauer. Gemäß eines weiteren Aspekts der Erfindung wird das Ventil einer Pumpe-Düse-Vorrichtung entsprechend gesteuert. Die Pumpe-Düse-Vorrichtung hat eine Pumpe, die einen Kolben und einen Arbeitsraum hat, eine Steuereinheit, die einen Ablaufkanal, der hydraulisch gekoppelt ist mit dem Arbeitsraum, und ein Ventil umfasst, mit einem als Piezoaktor ausgebildeten Ventilantrieb, einem Ventilglied, einem Ventilkörper, einem Ventilsitz und einem Absteuerraum, der hydraulisch entkoppelt ist von dem Ablaufkanal, wenn das Ventilglied an dem Ventilsitz anliegt, und der ansonsten gekoppelt ist mit dem Ablaufkanal.The invention is characterized by a method for controlling a valve with a valve drive, which is designed as a piezoelectric actuator, a valve member, a valve body and a valve seat. At a predetermined time, the valve member is controlled from a position away from the valve seat into the valve seat. While the valve member is being controlled from the position away from the valve seat into the valve seat, a signal characterizing the piezo voltage is detected. At least the first derivative of the signal characterizing the piezoelectric voltage is then determined. The time of impact of the valve member on the valve seat is detected when the at least first derivative of the signal exceeds a predetermined threshold. A closing time is determined depending on the predefinable time and the time of impact. The actuation of the valve drive then takes place depending on the closing time. According to a further aspect of the invention, the valve of a pump-nozzle device is controlled accordingly. The pump-nozzle apparatus has a pump having a piston and a working space, a control unit including a drain channel hydraulically coupled to the working space, and a valve having a valve actuator configured as a piezoactuator, a valve member, a valve body a valve seat and a spillway which is hydraulically decoupled from the drain passage when the valve member abuts the valve seat and which is otherwise coupled to the drain passage.

Der Erfindung liegt die Erkenntnis zugrunde, dass beim Auftreffen des Ventilglieds auf den Ventilsitz der Verlauf des die Piezospannung charakterisierenden Signals einen Knick aufweist und unmittelbar nach dem Knick eine höhere Steigung aufweist. Durch das Ermitteln der mindestens ersten Ableitung des die Piezospannung charakterisierenden Signals und des Erkennens des Zeitpunkts des Auftreffens des Ventilglieds auf den Ventilsitz, wenn die mindestens erste Ableitung des Signals einen vorgegebenen Schwellenwert überschreitet, ist einfach ein sehr präzises Bestimmen des Auftreffzeitpunkts gewährleistet. Das die Piezospannung charakterisierende Signal ist vorteilhaft die Piezospannung selbst. Es kann jedoch auch eine weitere die Piezospannung charakterisierende Größe sein, wie beispielsweise die Kapazität des Piezoaktors oder der Strom, mit dem der Piezoaktor beaufschlagt wird, oder die Ladung des Piezoaktors oder die elektrische Energie des Piezoaktors.The invention is based on the finding that the impact of the valve member on the valve seat, the course of the piezoelectric voltage characterizing signal has a kink and immediately after the kink has a higher slope. By determining the at least first derivative of the signal characterizing the piezoelectric voltage and detecting the time of impact of the valve member on the valve seat when the at least first derivative of the signal exceeds a predetermined threshold, a very precise determination of the time of impact is simply ensured. The signal characterizing the piezoelectric voltage is advantageously the piezoelectric voltage itself. However, it may also be a further variable characterizing the piezoelectric voltage, such as the capacitance of the piezoelectric actuator or the current applied to the piezoactuator, or the charge of the piezoactuator or the electrical energy of the piezoactuator piezoelectric actuator.

In einer vorteilhaften Ausgestaltung der Erfindung wird die mindestens erste Ableitung des Signals nur innerhalb eines vorgegebenen Zeitfensters um einen erwarteten Zeitpunkt des Auftreffens auf das Überschreiten des vorgegebenen Schwellenwerts überwacht. Dies hat den Vorteil eines geringeren Rechenaufwands und gleichzeitig einer geringeren Wahrscheinlichkeit einer Fehlbestimmung des Zeitpunkts des Auftreffens aufgrund von Störsignalen.In an advantageous embodiment of the invention, the at least first derivative of the signal is monitored only within a predetermined time window to an expected time of impact on exceeding the predetermined threshold. This has the advantage of less computational effort and at the same time a lower probability a misjudgment of the time of impact due to noise.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung wird das die Piezospannung charakterisierende Signal quadriert und dann mindestens die erste Ableitung des quadrierten Signals ermittelt. Dem liegt die Erkenntnis zugrunde, dass das die Piezospannung charakterisierende Signal einen im wesentlichen wurzelförmigen Verlauf hat und dass so das Signal durch das Quadrieren linearisiert werden kann und ein höherer Signal-Rauschabstand einfach erreicht werden kann.In a further advantageous embodiment of the invention, the piezoelectric voltage characterizing signal is squared and then determined at least the first derivative of the squared signal. This is based on the knowledge that the signal characterizing the piezoelectric voltage has a substantially root-shaped profile and that, thus, the signal can be linearized by squaring and a higher signal-to-noise ratio can be easily achieved.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung wird die zweite Ableitung des quadrierten Signals ermittelt. Dies hat den Vorteil, dass der charakteristische Knick des ursprünglichen Signals dann besonders gut und einfach erkannt werden kann.In a further advantageous embodiment of the invention, the second derivative of the squared signal is determined. This has the advantage that the characteristic kink of the original signal can then be recognized particularly well and easily.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung wird bei einem ersten Überschreiten des Schwellenwerts auf den Zeitpunkt des Auftreffens des Ventilglieds auf den Ventilsitz erkannt. Dies hat den Vorteil, dass es einfach und präzise ist.In a further advantageous embodiment of the invention is detected at a first exceeding of the threshold value to the time of impact of the valve member on the valve seat. This has the advantage of being simple and accurate.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung wird die Schließzeitdauer mehrfach ermittelt und einer Filterung unterzogen. Dies hat den Vorteil, dass so ein sehr zuverlässiger Wert der Schließzeitdauer ermittelt werden kann.In a further advantageous embodiment of the invention, the closing time period is determined several times and subjected to filtering. This has the advantage that such a very reliable value of the closing period can be determined.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung wird ein Fehler in dem Ventil erkannt, wenn die Schließzeitdauer kleiner als ein zweiter Schwellenwert oder größer als ein dritter Schwellenwert ist. Dies hat den Vorteil einer einfachen Diagnose des Ventils.In a further advantageous embodiment of the invention, a fault is detected in the valve when the closing time is less than a second threshold or greater than a third threshold. This has the advantage of a simple diagnosis of the valve.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung wird ein Ansteuerzeitpunkt des Ventilantriebs abhängig von der Schließzeitdauer und einem Sollwert der Schließzeitdauer korrigiert.In a further advantageous embodiment of the invention, a drive time of the valve drive depends on the closing time period and a set value of the closing time period corrected.

In einer weiteren vorteilhaften Ausgestaltung erfolgt diese Korrektur zusätzlich auch noch von einer abhängig von einer Temperatur die charakteristisch ist für die Temperatur des Ventils und abhängig der dem Piezoantrieb zugeführten elektrischen Energie. Dadurch ist dann ein äußerst präzises Ansteuern des Ventils gewährleistet.In a further advantageous embodiment, this correction is additionally carried out by a dependent on a temperature which is characteristic of the temperature of the valve and the electric power supplied to the piezo drive. This ensures an extremely precise control of the valve.

Gemäß des Aspekts des Steuerns des Ventils der Pumpe-Düse-Vorrichtung ist es vorteilhaft, wenn der vorgebbare Zeitpunkt, zu dem das Ventilglied von einer Position entfernt von dem Ventilsitz in den Ventilsitz gesteuert wird, so gewählt wird, dass der Kolben der Pumpe in seinem oberen Totpunkt ist und bleibt bis zum erwarteten Auftreffen des Ventilglieds auf den Ventilsitz. Dies hat den Vorteil, dass das Steuern des Ventilglieds von einer Position entfernt von dem Ventilsitz in den Ventilsitz lediglich zu dem Zweck des Bestimmens der Schließzeitdauer erfolgen kann, da während sich der Kolben in seinem oberen Totpunkt befindet, der Druck in dem Arbeitsraum der Pumpe im wesentlichen dem Niederdruckniveau entspricht und somit im wesentlichen konstant ist und ohnehin kein Druckaufbau zum Einleiten einer Kraftstoffzumessung erfolgen kann. Es hat sich überraschend gezeigt, dass sich so einfach eine sehr präzise Erfassung der Schließzeitdauer möglich ist.According to the aspect of controlling the valve of the pump-nozzle device, it is advantageous if the predeterminable time at which the valve member is controlled from a position away from the valve seat into the valve seat, is selected so that the piston of the pump in its Top dead center is and remains until the expected impact of the valve member on the valve seat. This has the advantage that the control of the valve member from a position away from the valve seat into the valve seat can be done only for the purpose of determining the closing time since, while the piston is at its top dead center, the pressure in the working space of the pump in FIG essentially corresponds to the low pressure level and thus is substantially constant and anyway no pressure build-up can be made to initiate a fuel metering. It has surprisingly been found that such a very simple detection of the closing time is possible.

Ausführungsbeispiele der Erfindung werden im folgenden anhand der schematischen Zeichnungen beschrieben. Es zeigen:

Figur 1
eine Pumpe-Düse-Vorrichtung mit einem Ventil und einer Vorrichtung zum Steuern des Ventils,
Figur 2
ein Blockdiagramm, das den Ablauf des Ermittelns einer Schließzeitdauer T_CL darstellt,
Figur 3
ein weiteres Blockdiagramm, das den Ablauf des Er- mittelns eines Korrekturwert T_SOI_OFS des Ansteu- erzeitpunkts T_SOI darstellt und
Figuren 4a
bis 4d zeitliche Verläufe der Piezospannung V_INJ, des Hubs CTRL_VL des Ventilglieds231, des Drucks P_H in dem Arbeitsraum 13 der Pumpe und der Ein- spritzmenge MFF.
Embodiments of the invention will be described below with reference to the schematic drawings. Show it:
FIG. 1
a pump-nozzle device with a valve and a device for controlling the valve,
FIG. 2
a block diagram illustrating the procedure of determining a closing time T_CL,
FIG. 3
a further block diagram illustrating the sequence of determining a correction value T_SOI_OFS the drive timing T_SOI and
FIGS. 4a
to 4d temporal courses of the piezoelectric voltage V_INJ, the stroke CTRL_VL of the valve member 232, the pressure P_H in the working chamber 13 of the pump and the injection quantity MFF.

Elemente gleicher Konstruktion und Funktion sind figurenübergreifend mit den gleichen Bezugszeichen gekennzeichnet.Elements of the same construction and function are identified across the figures with the same reference numerals.

Die Pumpe-Düse-Vorrichtung (Figur 1) umfasst eine Pumpeneinheit, eine Steuereinheit und eine Düseneinheit. Die Pumpe-Düse-Vorrichtung wird bevorzugt eingesetzt zum Zuführen von Kraftstoff in den Brennraum eines Zylinders einer Brennkraftmaschine. Die Brennkraftmaschine ist vorzugsweise als DieselBrennkraftmaschine ausgebildet. Die Brennkraftmaschine hat einen Ansaugtrakt zum Ansaugen von Luft, der mittels Gaseinlassventilen mit Zylindern koppelbar ist. Die Brennkraftmaschine weist ferner einen Abgastrakt auf, der über das Auslassventil gesteuert die aus den Zylindern auszustoßenden Gase abführt. Den Zylindern sind jeweils Kolben zugeordnet, die jeweils über eine Pleuelstange mit einer Kurbelwelle gekoppelt sind. Die Kurbelwelle ist mit einer Nockenwelle gekoppelt.The pump-nozzle device ( FIG. 1 ) comprises a pump unit, a control unit and a nozzle unit. The pump-nozzle device is preferably used for supplying fuel into the combustion chamber of a cylinder of an internal combustion engine. The internal combustion engine is preferably designed as a diesel engine. The internal combustion engine has an intake tract for intake of air, which can be coupled by means of gas inlet valves with cylinders. The internal combustion engine also has an exhaust tract, which discharges the gases to be discharged from the cylinders via the outlet valve. The cylinders are each assigned pistons, which are each coupled via a connecting rod with a crankshaft. The crankshaft is coupled to a camshaft.

Die Pumpeneinheit umfasst einen Kolben 11, einen Pumpenkörper 12, einen Arbeitsraum 13 und ein Pumpen-Rückstellmittel 14, das vorzugsweise als Feder ausgebildet ist. Der Kolben 11 ist im eingebauten Zustand in einer Brennkraftmaschine mit einer Nockenwelle 16 gekoppelt, vorzugsweise mittels eines Kipphebels, und wird von dieser angetrieben. Der Kolben 11 ist in einer Ausnehmung des Pumpenkörpers 12 geführt und bestimmt abhängig von seiner Position das Volumen des Arbeitsraums 13. Das Pumpen-Rückstellmittel 14 ist so ausgebildet und angeordnet, dass das durch den Kolben 11 begrenzte Volumen des Arbeitsraums 13 einen Maximalwert aufweist, wenn auf den Kolben 11 keine äußeren Kräfte einwirken, d. h. Kräfte, die über die Kopplung mit der Nockenwelle 16 übertragen werden.The pump unit comprises a piston 11, a pump body 12, a working space 13 and a pump return means 14, which is preferably designed as a spring. The piston 11 is coupled in the installed state in an internal combustion engine with a camshaft 16, preferably by means of a rocker arm, and is driven by this. The piston 11 is guided in a recess of the pump body 12 and determined depending on its position, the volume of the working space 13. The pump return means 14 is formed and arranged so that the limited volume of the piston 11 through the working space 13 has a maximum value when acting on the piston 11 no external forces, ie forces that are transmitted via the coupling with the camshaft 16.

Die Düseneinheit umfasst einen Düsenkörper 51, in dem ein Düsenrückstellmittel 52, das als Feder und ggf. zusätzlich als Dämpfungseinheit ausgebildet ist, und eine Düsennadel 53 angeordnet sind. Die Düsennadel 53 ist in einer Ausnehmung des Düsenkörpers 51 angeordnet und wird im Bereich einer Nadelführung 55 geführt.The nozzle unit comprises a nozzle body 51, in which a nozzle return means 52, which is designed as a spring and possibly additionally as a damping unit, and a nozzle needle 53 are arranged. The nozzle needle 53 is arranged in a recess of the nozzle body 51 and is guided in the region of a needle guide 55.

In einem ersten Zustand liegt die Düsennadel 53 an einem Nadelsitz 54 an und verschließt so eine Düse 56, die zum Zuführen des Kraftstoffs in den Brennraum des Zylinders der Brennkraftmaschine vorgesehen ist. Die Düseneinheit ist vorzugsweise, wie dargestellt, als nach innen öffnende Düseneinheit ausgebildet.In a first state, the nozzle needle 53 abuts a needle seat 54 and thus closes a nozzle 56, which is provided for supplying the fuel into the combustion chamber of the cylinder of the internal combustion engine. The nozzle unit is preferably, as shown, formed as an inwardly opening nozzle unit.

In einem zweiten Zustand ist die Düsennadel 53 leicht beabstandet zu dem Nadelsitz 54 und zwar hin in Richtung zu dem Düsenrückstellmittel 52 angeordnet und gibt so die Düse 56 frei. In diesem zweiten Zustand wird Kraftstoff in den Brennraum des Zylinders der Brennkraftmaschine zugemessen. Der erste oder zweite Zustand wird eingenommen abhängig von einer Kräftebilanz aus der Kraft, die durch das Düsenrückstellmittel 52 auf die Düsennadel 53 wirkt und aus der dieser entgegenwirkenden Kraft, die durch den hydraulischen Druck im Bereich des Nadelabsatzes 57 hervorgerufen wird.In a second state, the nozzle needle 53 is slightly spaced from the needle seat 54 toward the nozzle return means 52, thus releasing the nozzle 56. In this second state, fuel is metered into the combustion chamber of the cylinder of the internal combustion engine. The first or second state is assumed depending on a balance of forces from the force acting on the nozzle needle 53 by the nozzle return means 52 and the counteracting force which is caused by the hydraulic pressure in the region of the needle heel 57.

Die Steuereinheit umfasst einen Zulaufkanal 21 und einen Ablaufkanal 22. Der Zulaufkanal 21 und der Ablaufkanal 22 sind mittels eines Ventils hydraulisch koppelbar. Der Zulaufkanal 21 ist von einem niederdruckseitigen Anschluss der Pumpe-Düse-Vorrichtung hin zu dem Ventil geführt. Der Ablaufkanal 22 ist hydraulisch mit dem Arbeitsraum 13 gekoppelt und ist hin zu dem Nadelabsatz 57 geführt und ist hydraulisch mit der Düse 56 koppelbar abhängig von dem Zustand, der von der Düsennadel 53 eingenommen wird.The control unit comprises an inlet channel 21 and an outlet channel 22. The inlet channel 21 and the outlet channel 22 can be hydraulically coupled by means of a valve. The inlet channel 21 is guided from a low-pressure side connection of the pump-nozzle device to the valve. The drain passage 22 is hydraulically coupled to the working space 13 and is guided to the needle heel 57 and is hydraulically with the Nozzle 56 can be coupled depending on the condition occupied by the nozzle needle 53.

Das Ventil umfasst ein Ventilglied 231, das vorzugsweise als sog. A-Ventil ausgebildet ist, d. h. es öffnet nach außen entgegen der Strömungsrichtung des Fluids. Das Ventil umfasst ferner einen Absteuerraum 232, der hydraulisch gekoppelt ist mit dem Zulaufkanal 21 und mittels des Ventilglieds 231 mit einem Hochdruckraum hydraulisch koppelbar ist. Der Hochdruckraum ist hydraulisch gekoppelt mit dem Ablaufkanal 22.The valve comprises a valve member 231, which is preferably designed as a so-called. A valve, d. H. it opens outward against the flow direction of the fluid. The valve further comprises a Absteuerraum 232 which is hydraulically coupled to the inlet channel 21 and by means of the valve member 231 with a high-pressure chamber is hydraulically coupled. The high-pressure chamber is hydraulically coupled to the drainage channel 22.

In der geschlossenen Stellung des Ventilglieds 231 liegt das Ventilglied 231 an einem Ventilsitz 234 eines Ventilkörpers 237 an. Ferner ist ein Ventilrückstellmittel vorgesehen, welches so angeordnet und ausgebildet ist, dass es das Ventilglied 231 in eine Offenstellung, d. h. beabstandet zu dem Ventilsitz 234 drückt, wenn die durch einen Stellantrieb 24 auf das Ventilglied wirkenden Kräfte geringer sind als die Kräfte, die durch das Ventilrückstellmittel auf das Ventilglied 231 wirken. Der Stellantrieb 24 ist als Piezostapel ausgebildet.In the closed position of the valve member 231, the valve member 231 abuts against a valve seat 234 of a valve body 237. Further, a valve return means is provided, which is arranged and formed so that it the valve member 231 in an open position, d. H. spaced apart from the valve seat 234 when the forces acting on the valve member by an actuator 24 are less than the forces acting on the valve member 231 by the valve return means. The actuator 24 is formed as a piezo stack.

Der Stellantrieb 24 ist vorzugsweise mittels eines Übertragers, der vorzugsweise den Hub des Stellantriebs 24 verstärkt, mit dem Ventilglied 231 gekoppelt. An dem Stellantrieb 24 ist vorzugsweise auch ein Stecker zur Aufnahme von elektrischen Kontakten zur Ansteuerung des Stellantriebs 24 vorgesehen.The actuator 24 is preferably coupled to the valve member 231 by means of a transformer which preferably amplifies the stroke of the actuator 24. On the actuator 24 is preferably also a plug for receiving electrical contacts for driving the actuator 24 is provided.

Eine Vorrichtung 60 zum Steuern der Pumpe-Düse-Vorrichtung ist vorgesehen, die entsprechende Stellsignale für das Ventil erzeugt.A device 60 for controlling the pump-nozzle device is provided, which generates corresponding actuating signals for the valve.

In der Offenstellung des Ventilglieds 231 wird bei einer Bewegung des Kolbens 11, die nach oben d. h. in Richtung weg von der Düse 56 gerichtet ist, Kraftstoff über den Zulaufkanal 21 hin zum Arbeitsraum 13 angesaugt. Solange das Ventilglied 231 während einer anschließenden Abwärtsbewegung des Kolbens 11, d. h. bei einer hin zu der Düse 56 gerichteten Bewegung, weiterhin in seiner Offenstellung befindet, wird der in dem Arbeitsraum 13 und dem Ablaufkanal 22 befindliche Kraftstoff über das Ventil wieder zurück in den Absteuerraum 232 und ggf. in den Zulaufkanal 21 zurückgedrückt.In the open position of the valve member 231 is sucked in a movement of the piston 11, which is directed upward, ie in the direction away from the nozzle 56, fuel via the inlet channel 21 to the working space 13. As long as the valve member 231 during a subsequent downward movement of the piston 11, ie in a directed towards the nozzle 56 movement, is still in its open position, located in the working chamber 13 and the drain passage 22 fuel through the valve back into the Absteuerraum 232 and possibly pushed back into the inlet channel 21.

Wenn jedoch bei der Abwärtsbewegung des Kolbens 11 das Ventilglied 231 in seine geschlossene Stellung gesteuert ist, wird der im Arbeitsraum 13 und somit auch der im Ablaufkanal 22 und der in dem Hochdruckraum 233 befindliche Kraftstoff verdichtet, wodurch der Druck mit zunehmender Abwärtsbewegung des Kolbens 11 im Arbeitsraum 13, im Hochdruckraum 233 und im Ablaufkanal 22 zunimmt. Entsprechend dem steigenden Druck im Ablaufkanal 22 erhöht sich auch die durch den Hydraulikdruck hervorgerufene Kraft, die auf den Nadelabsatz 57 in Richtung einer Öffnungsbewegung der Düsennadel 53 zum Freigeben der Düse 56 wirkt. Wenn der Druck in dem Ablaufkanal 22 einen Wert überschreitet, bei dem die durch den Hydraulikdruck hervorgerufene Kraft auf den Nadelabsatz 57 größer ist als die dieser entgegenwirkende Kraft des Düsenrückstellmittels 52, bewegt sich die Düsennadel 53 weg vom Nadelsitz 54 und gibt so die Düse 56 für die Kraftstoffzufuhr zum Zylinder der Brennkraftmaschine frei. Die Düsennadel 53 bewegt sich dann wieder hinein in den Nadelsitz 54 und verschließt somit die Düse 56, wenn der Hydraulikdruck in dem Ablaufkanal 22 den Wert unterschreitet, bei dem die durch den Hydraulikdruck am Nadelabsatz 57 hervorgerufene Kraft kleiner ist als die durch das Düsenrückstellmittel 52 hervorgerufene Kraft. Der Zeitpunkt, an dem dieser Wert unterschritten wird und an dem somit die Kraftstoffzumessung beendet wird, kann durch das Steuern des Ventilglieds 231 von seiner geschlossenen Stellung in eine Offenstellung beeinflusst werden.However, when the valve member 231 is controlled in its closed position during the downward movement of the piston 11, the fuel in the working chamber 13 and thus in the flow passage 22 and in the high-pressure chamber 233 is compressed, whereby the pressure with increasing downward movement of the piston 11 in the Working space 13, in the high-pressure chamber 233 and in the drain passage 22 increases. In accordance with the increasing pressure in the discharge channel 22, the force caused by the hydraulic pressure increases, which acts on the needle shoulder 57 in the direction of an opening movement of the nozzle needle 53 to release the nozzle 56. When the pressure in the drain passage 22 exceeds a value at which the force on the needle hub 57 caused by the hydraulic pressure is greater than the counteracting force of the nozzle return means 52, the nozzle needle 53 moves away from the needle seat 54, thus giving the nozzle 56 for the fuel supply to the cylinder of the internal combustion engine free. The nozzle needle 53 then moves back into the needle seat 54 and thus closes the nozzle 56 when the hydraulic pressure in the drain passage 22 falls below the value at which the force caused by the hydraulic pressure at the needle heel 57 is smaller than that caused by the nozzle return means 52 Force. The time at which this value is exceeded and at which thus the fuel metering is terminated, can be influenced by the control of the valve member 231 from its closed position to an open position.

Durch das Steuern des Ventilglieds von seiner Schließstellung in seine Offenstellung wird die hydraulische Kopplung zwischen dem Hochdruckraum und dem Absteuerraum 232 und dem Zulaufkanal 21 hergestellt. Aufgrund des beim Öffnen herrschenden hohen Druckunterschiedes zwischen dem Fluid in dem Hochdruckraum und dem Ablaufkanal 22 und dem Fluid in dem Absteuerraum 232 und dem Zulaufkanal 21 strömt dann der Kraftstoff von dem Hochdruckraum mit sehr hoher Geschwindigkeit, in der Regel mit Schallgeschwindigkeit, in den Absteuerraum 232 und weiter in den Zulaufkanal 21. Dadurch wird dann der Druck in dem Hochdruckraum und dem Ablaufkanal 22 schnell so stark verringert, dass die von dem Düsenrückstellmittel 52 auf die Düsennadel 53 wirkenden Kräfte dazu führen, dass sich die Düsennadel 53 in den Nadelsitz 54 bewegt und somit dann die Düse 56 verschließt.By controlling the valve member from its closed position to its open position, the hydraulic coupling between the high-pressure chamber and the Absteuerraum 232 and the inlet channel 21 produced. Due to the high pressure difference prevailing during opening between the fluid in the high-pressure space and the outlet channel 22 and the fluid in the discharge space 232 and the inlet channel 21, the fuel then flows from the high-pressure space into the discharge space 232 at very high speed, generally at the speed of sound and further into the inlet channel 21. As a result, the pressure in the high-pressure chamber and the outlet channel 22 is then rapidly reduced so much that the forces acting on the nozzle needle 53 by the nozzle return means 52 cause the nozzle needle 53 to move into the needle seat 54 and Thus then the nozzle 56 closes.

Der Ablauf des Bestimmens eines Mittelwerts T_CL_MV der Schließzeitdauer des Ventilglieds 231, d.h. der Zeitdauer von dem Beginn der Ansteuerung des Ventilglieds 231 bis zum tatsächlichen Auftreffen des Ventilglieds 231 auf seinen Ventilsitz 234 wird im folgenden anhand von dem Blockdiagramm der Figur 2 beschrieben.The process of determining an average value T_CL_MV of the closing time duration of the valve member 231, ie, the time from the start of the actuation of the valve member 231 to the actual impact of the valve member 231 on its valve seat 234 will be described below with reference to the block diagram of FIG FIG. 2 described.

Zu einem vorgebbaren Zeitpunkt wird das Ventilglied von einer Position entfernt von dem Ventilsitz 234 in den Ventilsitz 234 gesteuert. Der vorgebbare Zeitpunkt wird vorzugsweise so gewählt, dass der Kolben in seinem oberen Totpunkt ist und bleibt bis zu dem erwarteten Auftreffen des Ventilglieds 231 auf den Ventilsitz 234. Er kann jedoch auch innerhalb eines Zeitbereichs gewählt sein, in dem sich der Kolben nicht in seinem oberen Totpunkt befindet.At a predetermined time, the valve member is controlled from a position away from the valve seat 234 into the valve seat 234. The predetermined time is preferably chosen so that the piston is in its top dead center and remains until the expected impact of the valve member 231 on the valve seat 234. However, it can also be selected within a time range in which the piston is not in its upper Dead center is located.

Während das Ventilglied 231 von der Position entfernt von dem Ventilsitz 234, die vorzugsweise eine definierte Position, wie beispielsweise ein Anschlag ist, an dem das Ventil anliegt, in den Ventilsitz 234 gesteuert wird, wird ein die Piezospannung charakterisierendes Signal in dem Block B1 erfasst. Bevorzugt ist dies die Piezospannung V_INJ selbst. Es kann jedoch auch eine weitere die Piezospannung charakterisierende Größe sein, wie beispielsweise die Kapazität des Piezoaktors oder der Strom, mit dem der Piezoaktor beaufschlagt wird, oder die Ladung des Piezoaktors oder die elektrische Energie des Piezoaktors.While the valve member 231 is controlled into the valve seat 234 from the position remote from the valve seat 234, which is preferably a defined position such as a stop against which the valve abuts, a signal characterizing the piezo voltage is detected in the block B1. This is preferably the piezo voltage V_INJ itself. However, it may also be a further variable characterizing the piezoelectric voltage, such as, for example, the capacitance of the piezoelectric voltage Piezo actuator or the current that is applied to the piezoelectric actuator, or the charge of the piezoelectric actuator or the electrical energy of the piezoelectric actuator.

In dem Block B1 wird die Piezospannung V_INJ, die Werte bis zirka 150 V annehmen kann, mittels eines Spannungsteilers in einen vorgegebenen Spannungsbereich transformiert und gegebenenfalls anschließend noch gefiltert. Anschließend erfolgt dann eine Analog-Digital-Wandlung des Signals mittels eines sogenannten Sample and Hold-Analog-Digital-Wandlers mit einer sehr geringen Abtastzeit von wenigen µsek. Die so erhaltenen digitalen Spannungswerte werden vorzugsweise zwischengespeichert und erst nach einem erwarteten Auftreffen des Ventilglieds 231 auf seinen Ventilsitz 234 weiter verarbeitet. Aufgrund der bekannten Abtastrate des Analog-Digital-Wandlers ist dann auch eine zeitliche Zuordnung der einzelnen abgetasteten Werte möglich.In the block B1, the piezo voltage V_INJ, which can assume values up to approximately 150 V, is transformed by means of a voltage divider into a predetermined voltage range and optionally subsequently filtered. Subsequently, an analog-to-digital conversion of the signal takes place by means of a so-called sample-and-hold analog-to-digital converter with a very short sampling time of a few μsec. The digital voltage values thus obtained are preferably temporarily stored and processed further only after an expected impingement of the valve member 231 on its valve seat 234. Due to the known sampling rate of the analog-to-digital converter, a time assignment of the individual sampled values is then also possible.

In einem Block B3 wird die abgetastete Piezospannung V_INJ noch vorzugsweise interpoliert, wodurch sich eine höhere zeitliche Auflösung des Signalverlaufs der Piezospannung V_INJ erreichen lässt. Dies erfolgt vorzugsweise mittels eines Finite-Impuls-Response (FIR)-Filters.In a block B3, the sampled piezo voltage V_INJ is still preferably interpolated, whereby a higher temporal resolution of the signal curve of the piezo voltage V_INJ can be achieved. This is preferably done by means of a finite impulse response (FIR) filter.

In einem Block B5 wird die Piezospannung V_INJ quadriert. Dies entspricht einem Linearisieren des Verlaufs der Piezospannung V_INJ, da diese einen im wesentlichen wurzelförmigen Verlauf hat. Alternativ kann jedoch auch auf das Quadrieren verzichtet werden, was durch den strichlierten Pfeil angedeutet ist.In a block B5, the piezo voltage V_INJ is squared. This corresponds to a linearization of the course of the piezoelectric voltage V_INJ, since this has a substantially root-shaped course. Alternatively, however, can be dispensed with the squaring, which is indicated by the dashed arrow.

In einem Block B7 wird dann die erste Ableitung des Signalverlaufs der Piezospannung V_INJ ermittelt. Es erfolgt somit eine Differenzierung nach der Zeit. Alternativ kann in einem Block B9 auch eine zweite Ableitung des Signalverlaufs der Piezospannung V_INJ ermittelt werden. Alternativ kann aber auch eine dritte, vierte, fünfte oder höhere Ableitung des Signalverlaufs der Piezospannung V_INJ ermittelt werden.In a block B7, the first derivative of the signal curve of the piezo voltage V_INJ is then determined. There is thus a differentiation according to the time. Alternatively, in a block B9, a second derivative of the signal curve of the piezo voltage V_INJ can be determined. Alternatively, you can but also a third, fourth, fifth or higher derivative of the waveform of the piezoelectric voltage V_INJ be determined.

In einem Block B11 werden dann lediglich die Werte der abgeleiteten Piezospannung V_INJ ausgewählt, die innerhalb eines vorgegebenen Zeitfensters um den erwarteten Zeitpunkt des Auftreffens des Ventilglieds 231 auf den Ventilsitz 234 erfasst wurden. Das Zeitfenster ist dabei vorzugsweise so vorgegeben, dass alle bekannten Streuungen der Schließzeitdauer berücksichtigt sind.In a block B11 then only the values of the derived piezo voltage V_INJ are selected, which were detected within a predetermined time window by the expected time of impact of the valve member 231 on the valve seat 234. The time window is preferably predetermined so that all known variations of the closing time period are taken into account.

In einem Block B13 wird geprüft, welcher der abgeleiteten Werte der Piezospannung V_INJ erstmalig einen vorgegebenen ersten Schwellenwert SW1 überschreitet. Abhängig von dem diesem Wert zugeordneten Zeitpunkt und dem bekannten Beginn der Ansteuerung des Ventilantriebs 24 wird in dem Block B13 dann die Schließzeitdauer T_CL ermittelt.In a block B13, it is checked which of the derived values of the piezo voltage V_INJ first exceeds a predetermined first threshold value SW1. Depending on the time associated with this value and the known start of the activation of the valve drive 24, the closing time T_CL is then determined in the block B13.

In einem Block B15 wird dann plausibilisiert, ob die Schließzeitdauer T_CL kleiner ist als ein vorgegebener zweiter Schwellenwert oder größer ist als ein vorgegebener dritter Schwellenwert SW3. Der zweite und dritte Schwellenwert SW2, SW3 sind so gewählt, dass ein Unterschreiten bzw. Überschreiten nur im Falle eines Fehlers des Ventils möglich ist. Entsprechend wird dann einem Unterschreiten bzw. Überschreiten ein Fehler des Ventils in dem Block B15 diagnostiziert.In a block B15, it is then made plausible whether the closing time period T_CL is less than a predetermined second threshold value or greater than a predetermined third threshold value SW3. The second and third thresholds SW2, SW3 are selected so that falling below or exceeding is possible only in the case of a fault of the valve. Accordingly, a failure of the valve in block B15 is then diagnosed.

In einem Block B17 wird anschließend die ermittelte Schließzeitdauer T_CL einer statistischen Auswertung unterzogen. Bevorzugt wird die Schließzeitdauer T_CL mehrfach, so z.B. dreißig mal ermittelt und dann der Mittelwert und gegebenenfalls die Standardabweichung der erhaltenen Schließzeitdauer T_CL ermittelt. Der Block B17 gibt vorzugsweise den Mittelwert T_CL_MV der Schließzeitdauer aus. Alternativ können jedoch auch die ermittelten Schließzeitdauern T_CL auf andere Art und Weise gefiltert werden, wie z.B. mittels einer gleitenden Mittelwertbildung oder eines nicht-rekursiven Filters. Ein Korrekturwert T_SOI_OFS für den Ansteuerzeitpunkt T_SOI des Ventilantriebs 24 wird gemäß dem Blockdiagramm von Figur 3 ermittelt. In einem Block B13 wird abhängig von einer Temperatur TEMP, die charakteristisch ist für die Temperatur des Ventilantriebs 24 und mithin des Piezoaktors und einer dem Ventilantrieb 24 zugeführten Energie E und abhängig von einem Sollwert T_CL_SP der Schließzeitdauer ein erster Korrekturwert T_CL_COR1 ermittelt. Der erste Korrekturwert T_CL_COR1 ist ein Schätzwert, der Änderung der Schließzeitdauer abhängig von der Temperatur TEMP und der zugeführten elektrischen Energie E. Der Sollwert T_CL_SP der Schließzeitdauer ist vorzugsweise gegeben für vorgegebene Betriebsbedingungen, d.h. für eine vorgegebene Temperatur TEMP und zugeführte elektrische Energie E. Er ist vorzugsweise für die während des Betriebs des Ventilantriebs 24 im Mittel herrschende Temperatur TEMP und der ihm im Mittel zugeführten elektrischen Energie ermittelt. Der Block B19 beinhaltet dementsprechend ein entsprechendes Modell, mittels dessen dann der erste Korrekturwert T_CL_COR1 ermittelt wird.In a block B17, the determined closing time T_CL is subsequently subjected to a statistical evaluation. Preferably, the closing time period T_CL is determined several times, for example thirty times, and then the mean value and, if appropriate, the standard deviation of the closing time duration T_CL obtained are determined. The block B17 preferably outputs the mean value T_CL_MV of the closing time period. Alternatively, however, the determined closing time durations T_CL can be filtered in a different manner, for example by means of a moving averaging or a non-recursive filter. A correction value T_SOI_OFS for the actuation time T_SOI of the valve drive 24 is determined according to the block diagram of FIG FIG. 3 determined. In a block B13, a first correction value T_CL_COR1 is determined as a function of a temperature TEMP which is characteristic for the temperature of the valve drive 24 and thus of the piezoactuator and an energy E supplied to the valve drive 24 and dependent on a setpoint value T_CL_SP of the closing time duration. The first correction value T_CL_COR1 is an estimated value of the change of the closing time duration depending on the temperature TEMP and the supplied electric energy E. The closing time period T_CL_SP is preferably given for predetermined operating conditions, ie for a predetermined temperature TEMP and supplied electric energy E. Er preferably determined for the prevailing during operation of the valve drive 24 in the average temperature TEMP and the electrical energy supplied to it on average. The block B19 accordingly contains a corresponding model, by means of which the first correction value T_CL_COR1 is then determined.

In einem Block B21 wird ein zweiter Korrekturwert T_CL_COR2 abhängig von dem Sollwert T_CL_SP und dem Mittelwert T_CL_MV der Schließzeitdauer ermittelt. Dies erfolgt vorzugsweise durch Bilden der Differenz des Sollwertes T_CL_SP und des Mittelwertes T_CL_MV der Schließzeitdauer und multiplizieren dieser Differenz mit einem vorgebbaren Faktor.In a block B21, a second correction value T_CL_COR2 is determined as a function of the desired value T_CL_SP and the average value T_CL_MV of the closing time duration. This is preferably done by forming the difference of the setpoint value T_CL_SP and the mean value T_CL_MV of the closing time duration and multiplying this difference by a predefinable factor.

In einem Block B23 wird dann abhängig von dem ersten Korrekturwert T_CL_COR1 und dem zweiten Korrekturwert T_CL_COR2 ein Korrekturwert T_SOI_OFS für den Ansteuerzeitpunkt T_SOI ermittelt, vorzugsweise durch Bilden der Summe des ersten und zweiten Korrekturwertes T_CL_COR1, T_CL_COR2.In a block B23, depending on the first correction value T_CL_COR1 and the second correction value T_CL_COR2, a correction value T_SOI_OFS for the activation time T_SOI is then determined, preferably by forming the sum of the first and second correction values T_CL_COR1, T_CL_COR2.

In einem Block B25 wird dann abhängig von dem Korrekturwert T_SOI_OFS für den Ansteuerzeitpunkt T_SOI und eines angeforderten Zeitpunkts, zu dem das Ventilglied 231 auf seinen Ventilsitz 234 treffen soll, der Ansteuerzeitpunkt T_SOI ermittelt.In a block B25 then becomes dependent on the correction value T_SOI_OFS for the drive time T_SOI and a requested time at which the valve member 231 on its valve seat 234, the triggering time T_SOI determined.

Figuren 4a bis 4d zeigen Verläufe aufgetragen über die Zeit t. Figur 4a zeigt den zeitlichen Verlauf der quadrierten Piezospannung V_INJ. Figur 4b zeigt den Hub CTRL_VL des Ventilglieds 231. Figur 4c zeigt den Verlauf des Drucks P_H in dem Arbeitsraum 13 der Pumpe. Figur 4d zeigt den zeitlichen Verlauf der mit der Pumpe-Düse-Vorrichtung zugemessenen Kraftstoffmenge MFF. Zu dem Ansteuerzeitpunkt T_SOI wird der Ventilantrieb 24 mit Spannung, der Piezospannung V_INJ beaufschlagt. Zu einem Zeitpunkt t1 trifft das Ventilglied 231 auf den Ventilsitz 234. Die Steigung, des im wesentlichen linearen Verlaufs der quadrierten Piezospannung V_INJ nimmt in dem Zeitpunkt t1 dann sprungartig zu. Der Druck P_H in dem Arbeitsraum 13 der Pumpe beginnt ab dem Zeitpunkt t1 zu steigen. Zum Zeitpunkt t2 wird der zum Öffnen der Düsennadel 53 erforderliche Druck erreicht und der Einspritzvorgang beginnt. Bevorzugt erfolgt das Ermitteln der Schließzeitdauer jedoch während einer Zeitdauer, während der der Kolben 11 in seinem oberen Totpunkt ist. Dies hat dann zur Folge, dass der Verlauf des Drucks P_H in dem Arbeitsraum 13 im wesentlichen konstant ist und zwar auf Niederdruckniveau mit der Folge, dass die zugemessene Kraftstoffmenge MFF gemäß Figur 4c null ist. FIGS. 4a to 4d show gradients plotted over time t. FIG. 4a shows the time course of the squared piezo voltage V_INJ. FIG. 4b shows the stroke CTRL_VL of the valve member 231. Figure 4c shows the course of the pressure P_H in the working space 13 of the pump. FIG. 4d shows the time course of the metered with the pump-nozzle device amount of fuel MFF. At the actuation time T_SOI, the valve drive 24 is subjected to voltage, the piezo voltage V_INJ. At a time t1, the valve member 231 impinges on the valve seat 234. The slope of the substantially linear curve of the squared piezo voltage V_INJ then increases suddenly at the instant t1. The pressure P_H in the working space 13 of the pump begins to increase from time t1. At time t2, the pressure required to open the nozzle needle 53 is reached and the injection process begins. Preferably, however, the determination of the closing period takes place during a period during which the piston 11 is in its upper dead center. This then has the consequence that the course of the pressure P_H in the working space 13 is substantially constant, namely at low pressure level with the result that the metered amount of fuel MFF according to Figure 4c is zero.

BezugszeichenlisteLIST OF REFERENCE NUMBERS Pumpe/PumpeneinheitPump / pump unit

1111
Kolbenpiston
1212
Pumpenkörperpump body
1313
Arbeitsraumworking space
1414
PumpenrückstellmittelPumps return means
1616
Nockenwellecamshaft
Steuereinheitcontrol unit

2121
Zulaufkanalinlet channel
2222
Ablaufkanaldrain channel
231231
Ventilgliedvalve member
232232
Absteuerraumdiversion chamber
234234
Ventilsitzvalve seat
237237
Ventilkörpervalve body
2424
Ventilantriebvalve drive
Düseneinheitnozzle unit

5151
Düsenkörpernozzle body
5252
DüsenrückstellmittelNozzle return means
5353
Düsennadelnozzle needle
5454
Nadelsitzneedle seat
5555
Nadelführungneedle guide
5656
Düsejet
5757
Nadelabsatzneedle shoulder
6060
Vorrichtung zum Steuern einer Pumpe-Düse- VorrichtungDevice for controlling a pump-nozzle device
V_INJV_INJ
Piezospannungpiezovoltage
SW1, SW2, SW3SW1, SW2, SW3
erster, zweiter, dritter Schwellenwertfirst, second, third threshold
T_CLT_CL
SchließzeitdauerClosing time
T_CL_MVT_CL_MV
Mittelwert der SchließzeitdauerAverage value of closing time
T_CL_SPT_CL_SP
Sollwert der SchließzeitdauerSetpoint of the closing time
T_CL_COR1T_CL_COR1
erster Korrekturwert (Schätzwert, Vorsteuer- wert)first correction value (estimated value, input tax value)
T_CL_COR2T_CL_COR2
zweiter Korrekturwert (Regelung)second correction value (control)
T_SOIT_SOI
Ansteuerzeitpunktcontrol time
T_SOI_OFST_SOI_OFS
Korrekturwert für den AnsteuerzeitpunktCorrection value for the activation time
TEMPTEMP
Temperaturtemperature
Ee
elektrische Energieelectrical power
Ctrl_VLCtrl_VL
Hub des VentilgliedsStroke of the valve member
P_HP_H
Druck in dem ArbeitsraumPressure in the workspace
MFFMFF
KraftstoffeinspritzmengeFuel injection quantity

Claims (12)

  1. Method for controlling a valve with a valve drive (24), which is embodied as a piezoactuator, with a valve element (231), a valve body (237) and a valve seat (234), in which
    - at a predetermined point in time the valve element (231) is controlled so that it moves from a position away from the valve seat (234) into the valve seat (234),
    - while the valve element (231) is being moved in a controlled manner from a position away from the valve seat (234) into the valve seat (234), a signal characterising the piezo voltage (V_INJ) is detected,
    - the signal characterising the piezo voltage (V_INJ) is squared and the at least first temporal deviation of the squared signal is determined,
    - the time at which the valve body (231 makes contact with the valve seat (234) is detected, when the at least first temporal deviation of the squared signal exceeds a predetermined first threshold value (SW1),
    - a close time (T_CL) is determined as a function of the predetermined time and the time at which contact is made and
    - the valve drive (24) is then activated as a function of the closing time (T_CL)
  2. Method according to claim 1,
    characterised in that
    the at least one temporal derivation of the signal is only monitored for the first predetermined threshold value (SW1) being exceeded during a predetermined time window around an expected time at which the valve element (231) makes contact with the valve seat (234).
  3. Method according to claim 1 or 2,
    characterised in that
    the second time derivation of the squared signal is determined.
  4. Method according to one of the previous claims,
    characterised in that
    the time at which the valve element (231) makes contact with the valve seat (234) is detected when the threshold value (SW1) is exceeded for the first time.
  5. Method according to one of the previous claims,
    characterised in that
    the closing time (T_CL) is determined a number of times and is subjected to filtering.
  6. Method according to one of the previous claims,
    characterised in that
    a fault in the valve is detected if the closing time duration is less than a second threshold value (SW2) or greater than a third threshold value (SW3).
  7. Method according to one of the previous claims,
    characterised in that
    a start of injection time (T_SOI) is determined as a function of the closing time (T_CL) and a setpoint value (T_CL_SP) of the closing time.
  8. Method according to claim 7,
    characterised in that
    the start of injection time (T_SOI) is additionally determined as a function of a temperature (TEMP), which is characteristic for the temperature of the valve, and an electrical energy (E) supplied to the valve drive (24).
  9. Method for controlling a unit injector with
    - a pump having a piston (11) and a working chamber (13),
    - a control unit, having an outlet channel (22) which is hydraulically coupled to the working chamber (13) and a valve, with a valve drive (24) embodied as a piezoactuator, a valve element (231), a valve body (237), a valve seat (234) and a cutoff control chamber (232), which is hydraulically decoupled from the outlet channel (22) when the valve element (231) is in contact with the valve seat (234), and which is otherwise hydraulically coupled to the outlet channel (22),
    - in which the valve is controlled with a method according to one of the above claims.
  10. Method according to claim 9,
    characterised in that
    the predeterminable time is chosen so that the piston (11) is at its top dead centre position and remains there until the expected contact between the valve element (231) and the valve seat (234).
  11. Apparatus for controlling a valve with a valve drive (24) embodied as a piezoactuator, with a valve element (231), a valve body (237) and a valve seat (234) having means
    - for moving the valve element (231) in a controlled manner at a predetermined time from a position away from the valve seat (234) into the valve seat (234),
    - which detect a signal (V_INJ) characterising the piezo voltage while the valve element (231) is being moved in a controlled manner from the position away from the valve seat (234) into the valve seat (234),
    - which square the signal (V_INJ) characterising the piezo voltage and then determine the at least first temporal deviation of the squared signal,
    - which detect the time at which the valve element (231) makes contact with the valve seat (234) when the at least first temporal deviation of the squared signal exceeds a predetermined first threshold value (SW1),
    - which determine a close time as a function of the predetermined time and the time at which contact is made and
    - which then activate the valve drive (24) as a function of the closing time (T_CL).
  12. An apparatus for controlling a unit injector with
    - a pump having a piston (11) and a working chamber (13),
    - a control unit, having an outlet channel (22) which is hydraulically coupled to the working chamber (13) and a valve, with a valve drive (24) embodied as a piezoactuator, a valve element (231), a valve body (237), a valve seat (234) and a cutoff control chamber (232), which is hydraulically decoupled from the outlet channel (22) when the valve element (231) is in contact with the valve seat (234), and which is otherwise hydraulically coupled to the outlet channel (22),
    - with the apparatus for controlling a valve according to claim 11.
EP20040022133 2003-09-29 2004-09-17 Method and device for controlling a valve and method and device for controlling pump-nozzle unit with a valve Expired - Fee Related EP1519026B1 (en)

Applications Claiming Priority (2)

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DE2003145226 DE10345226B4 (en) 2003-09-29 2003-09-29 Method and device for controlling a valve and method and device for controlling a pump-nozzle device with a valve
DE10345226 2003-09-29

Publications (3)

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EP1519026A2 EP1519026A2 (en) 2005-03-30
EP1519026A3 EP1519026A3 (en) 2006-10-25
EP1519026B1 true EP1519026B1 (en) 2010-12-29

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Application Number Title Priority Date Filing Date
EP20040022133 Expired - Fee Related EP1519026B1 (en) 2003-09-29 2004-09-17 Method and device for controlling a valve and method and device for controlling pump-nozzle unit with a valve

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DE502004012047D1 (en) 2011-02-10
DE10345226A1 (en) 2005-05-12
DE10345226B4 (en) 2006-04-06
EP1519026A2 (en) 2005-03-30
EP1519026A3 (en) 2006-10-25

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