WO2020104174A1 - Method for monitoring a speed-controlled electric motor pump of a hydraulic circuit in an aircraft and a hydraulic system for carrying out the method - Google Patents

Method for monitoring a speed-controlled electric motor pump of a hydraulic circuit in an aircraft and a hydraulic system for carrying out the method

Info

Publication number
WO2020104174A1
WO2020104174A1 PCT/EP2019/080030 EP2019080030W WO2020104174A1 WO 2020104174 A1 WO2020104174 A1 WO 2020104174A1 EP 2019080030 W EP2019080030 W EP 2019080030W WO 2020104174 A1 WO2020104174 A1 WO 2020104174A1
Authority
WO
WIPO (PCT)
Prior art keywords
hydraulic
pump
electric motor
cooling
aircraft
Prior art date
Application number
PCT/EP2019/080030
Other languages
German (de)
French (fr)
Inventor
Dirk Metzler
Original Assignee
Liebherr-Aerospace Lindenberg Gmbh
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Liebherr-Aerospace Lindenberg Gmbh filed Critical Liebherr-Aerospace Lindenberg Gmbh
Publication of WO2020104174A1 publication Critical patent/WO2020104174A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/10—Other safety measures
    • F04B49/106—Responsive to pumped volume
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity
    • F04B49/065—Control using electricity and making use of computers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/10—Other safety measures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B51/00—Testing machines, pumps, or pumping installations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2203/00—Motor parameters
    • F04B2203/02—Motor parameters of rotating electric motors
    • F04B2203/0209—Rotational speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/08—Pressure difference over a throttle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/09—Flow through the pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/10—Inlet temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2207/00—External parameters
    • F04B2207/70—Warnings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
    • F04B39/06—Cooling; Heating; Prevention of freezing
    • F04B39/064—Cooling by a cooling jacket in the pump casing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/08—Cooling; Heating; Preventing freezing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/40—Weight reduction

Definitions

  • the invention relates to a method for monitoring a speed-controlled electric motor pump of a hydraulic circuit in an aircraft, wherein the electric motor pump comprises at least one electric motor with a variable speed for driving the hydraulic pump and a hydraulic jacket cooling is provided for cooling the electric motor pump, which is supported by the pump hydraulic medium is flowed through.
  • Hydraulic systems for aircraft are known from the prior art, which comprise at least one electric motor pump with an uncontrolled electric motor.
  • Such electric motor pumps are purely hydromechanically pressure-controlled and operate by means of adjustable axial piston pumps with a variable absorption volume. It is not possible today to properly monitor such electric motor pumps known from the prior art, since the important information of the precisely conveyed flow cannot be determined if information on the speed and position of the turntable of the axial piston pump is missing. Due to this fact, electric motor pumps are associated with pump errors, which are noticeable by the deterioration in the volumetric pump efficiency and are not detectable today. If anything, a malfunction of the pump can only be determined during active operation, which can critically influence the flight mission and thus lead to large unplanned financial expenses for the operator.
  • an electric motor pump with variable-speed electric motor as a pump drive.
  • the electric motor pump is provided with a hydraulic jacket cooling for cooling the electric motor pump.
  • For monitoring the electric motor pump it is proposed to detect the volume flow through the jacket cooling at different motor speeds of the electric motor pump in order to determine the volumetric efficiency of the pump based on these volume flow values.
  • the volumetric efficiency is defined by the ratio of the actual volume flow of the pump to the theoretically possible volume flow of the pump. A decrease in the ratio corresponds to a deterioration in the pump efficiency, which can be an indication of a pump fault occurring.
  • An automatic monitoring function of the electric motor pump is created by the method according to the invention in order to ensure the fault-free operation of the pump function.
  • the electric motor pump can ideally be monitored using the so-called “continuous built-in test” (CBIT), which automatically diagnoses the fault-free operating state and only in the event of a fault appropriate maintenance actions initiated.
  • CBIT continuous built-in test
  • the determined volumetric efficiency of the pump is constantly monitored during flight operations and if there is a noticeable change in efficiency, e.g. a deviation from a reference value or if the value falls out of a tolerable value corridor, a warning message and / or maintenance request is displayed.
  • a suitable countermeasure is also initiated in the event of a correspondingly detected deviation from a reference value.
  • the volumetric efficiency of the pump to be monitored is defined as the ratio of the measured volume flow through the jacket cooling to the theoretical volume flow of the pump.
  • the theoretical volume flow results from the product of the current pump or motor speed and the current absorption volume of the pump. If the hydraulic pump installed is a constant pump, the theoretical volume flow is purely dependent on the speed.
  • the engine speed is known to the system from the engine control.
  • the method is carried out in a separate test cycle, that defined engine speeds are set, and the corresponding volumetric efficiencies are determined.
  • continuous monitoring takes place during normal flight operations, that is to say the volumetric efficiency of the pump is continuously recorded and monitored during the operation of the hydraulic system.
  • the volume flow through the jacket cooling is recorded directly by suitable sensors. Due to the required robustness of the sensors for an aircraft, the use of a differential pressure sensor is preferred. A Such a sensor measures, for example, the pressure drop across the jacket cooling. Under the premise that the jacket cooling is understood as a calibrated flow resistance, the volume flow through the jacket cooling can be calculated depending on the measured differential pressure, taking into account the physical interrelationships with hydraulic orifices. Further necessary parameters, for example the density and temperature of the hydraulic medium and the hydraulic resistance of the jacket cooling, are available to the control executing the method. In particular, a suitable temperature sensor in the area of the jacket cooling for detecting the medium temperature should be installed anyway in order to detect excessive heating of the hydraulic medium within the cooling jacket.
  • the jacket cooling is usually flowed through by the hydraulic medium from the low pressure side of the hydraulic circuit.
  • cooling in particular of the electric motor, is achieved via the integral jacket cooling.
  • cooling of the hydaulic medium may also be necessary. It is advisable to integrate a suitable heat exchanger in the hydraulic circuit, especially in the low-pressure area, in order to cool the hydraulic medium flowing through using a suitable heat sink.
  • a suitable heat sink can be, for example, the fuel tank of the aircraft.
  • the fuel tank is only available as a heat sink in the area of the wings, the use of an air-hydraulic heat exchanger is useful. Atmospheric air could be passed through the heat exchanger as the cooling medium.
  • an alternative, preferred approach is to use air from the printed area of the aircraft instead. Stuff, for example from the aircraft cabin, to flow through the heat exchanger as a cooling medium.
  • the present invention also relates to a hydraulic system of an aircraft with at least one speed-controlled electric motor pump with hydraulic jacket cooling.
  • the hydraulic system comprises a sensor system for direct or indirect volume flow measurement of the hydraulic flow through the jacket cooling and at least one controller for executing the method according to the invention.
  • the hydraulic system is obviously characterized by the same advantages and egg properties, as have already been shown above using the method according to the invention. For this reason, a repetitive description is omitted.
  • the electric motor pump is enclosed in a housing with integrated jacket cooling.
  • the corresponding sensors for flow measurement as well as a corresponding control for process execution are also available.
  • At least one hydraulic-air heat exchanger is preferably provided, which is expediently arranged in the low-pressure region of the hydraulic circuit. Cabin air can flow through the heat exchanger via an appropriate air duct. Due to the pressure difference in flight operations, this does not require any additional flow machines, the pressure difference ensures a sufficient flow speed through the heat exchanger.
  • the air flow from the printed cabin area can be controlled by at least one valve, for example temperature-dependent cooling to execute.
  • the valve is only opened and a cooling effect is generated when the maximum temperature value of the hydraulic medium is exceeded.
  • At least one fan can be arranged in the flow direction before and / or after the heat exchanger in order to support the conveying of the exhaust air into the atmosphere.
  • a fan is particularly advantageous when there is little or no pressure difference between the cabin pressure and the atmosphere, for example when the aircraft is on the ground.
  • the invention further relates to an aircraft with a corresponding hydraulic system according to the invention, so that the same advantages and properties also result with respect to the aircraft.
  • the hydraulic system is an isolated hydraulic system for primary flight control, for example for controlling the tail unit of an aircraft.
  • the corresponding hydraulic system is housed in the unprinted area, ideally in the rear or near the rear of the aircraft.
  • FIG. 3 a modified version of the hydraulic circuit according to the invention according to FIG. 2.
  • Figure 2 shows the structure of the hydraulic system according to the invention.
  • the electric motor pump 10 consists of a speed-controllable motor M which drives the constant pressure pump FDP.
  • a corresponding control computer MCE is used, among other things, to regulate the speed of the motor M.
  • the electric motor pump 10 is an integral part of a fly hydraulic system for the primary flight control of an aircraft.
  • the hole pressure output of the constant pressure pump FDP is connected via a check valve 2 and a high pressure filter 3 to at least one hydraulic consumer 4, in particular hydraulic actuator, for the mechanical actuation of the control surfaces.
  • the low-pressure side leads from the consumer 4 via a low-pressure filter 5 back to the hydraulic tank T, from which the constant pressure pump FDP sucks in hydraulic medium.
  • a pressure sensor 7 and a hydraulic accumulator are arranged between check valve 2 and high-pressure filter 3.
  • the overload valve 6 connects the high and low pressure side parallel to the consumer 4.
  • the falling differential pressures over the filters 3, 5 are optionally recorded in order to measure the degree of contamination of the filter.
  • the MCE control unit, the M motor and the FDP constant pressure pump form a module and are housed together in one housing.
  • the housing is equipped with hydraulic jacket cooling, which has an input and output connection, which are connected to each other via cooling channels embedded in the housing wall.
  • the inlet of the cooling jacket is connected to the filter 5, while the outlet opens into the tank T via connecting lines.
  • the hydraulic oil flowing through the channel structure of the housing ensures adequate cooling, in particular of the integral electric motor M.
  • the falling pressure over the jacket cooling of the electric motor pump 10 is detected.
  • a likewise provided temperature sensor 12 detects the temperature of the hydraulic medium at the outlet of the cooling device.
  • the volumetric efficiency h R, Vo / is defined by the ratio of the actual flow Q eff (Q measured) to the theoretically promoted flow Q th of the pump FDP. The latter is the product of the current speed n and the swallowing volume ⁇ / the pump FDP.
  • a corresponding corridor is defined by a maximum and minimum limit of the volumetric efficiency h R, v oi , as can be seen in FIG. 1. If the recorded volumetric efficiency h R, Voi exceeds a corresponding limit range, the MCE control unit generates and displays a warning message, possibly in combination with a request to carry out maintenance or repair work on the hydraulic system.
  • the determination of the actual flow rate Q eff required can be carried out in different ways, either directly via a flow sensor with any physical functional principle (calorimetric, ultrasound, paddlewheel) or, as shown in the exemplary embodiment in FIG. 2, by means of a calibrated one Flow resistance in connection with a differential pressure measurement and the physical parameters differential pressure Dr, fluid temperature T FiUid, fluid pressure p FiUid and density p of the hydraulic medium .
  • the corresponding flow rate Q eff is determined in the area of the hydraulic jacket cooling, the jacket cooling serving here as a calibrated large flow resistance.
  • the differential pressure sensor 11 continuously detects the differential pressure Dr above the jacket cooling and, taking into account the physical relationships with hydraulic orifices, the corresponding flow rate Q eff in accordance with:
  • the parameters for the calculation of the fluid density p are normally present in a corresponding hydraulic system, since the output pressure of the pump FDP is always measured for the control, here by means of the sensor 7, and usually the fluid temperature in the area of the jacket cooling is measured, here by means of the sensor 12.
  • the data from the pressure sensor 7, the differential pressure sensor 11, the temperature sensor 12 are continuously transmitted to the control MCE, which can then continuously compare the calculated volumetric efficiency of the pump FDP against the limit curves in FIG.
  • the signal lines are shown in FIG. 3, but are implemented identically in the example in FIG. 2.
  • the determination of the actually conveyed flow rate Q eff can be carried out continuously with a CBIT, since the hydraulic oil flowing back on the low-pressure side always flows back completely and continuously via the cooling jacket of the electric motor pump 10 as soon as it is in operation. In principle, this procedure can be used independently of the operating mode of the pump 10, ie for unidirectional or also for bidirectional operation of the electric motor pump 10.
  • Another aspect of the invention is that due to the continuous operation of the hydraulic system, cooling of the hydraulic medium may have to be ensured. This applies in particular when the hydraulic system is an isolated system for the primary flight control, for example for the control of the flight control unit in the rear area of the aircraft. As there is no adequate heat sink in the form of the kerosene tank available as with other hydraulic systems, an alternative must be used here. An additional ram air opening for the use of atmospheric cooling air should be avoided for fluidic reasons.
  • the system in FIG. 2 is expanded in the low-pressure region of the hydraulic circuit by at least one hydraulic-air heat exchanger 20; all other components are identical to the embodiment in FIG.
  • Agile cooling air is removed from the aircraft cabin via the valve 21 if necessary. Due to the pressure difference between cabin pressure and atmospheric pressure present in flight operation, the cabin air flows through the heat exchanger 20, from which it is released into the atmosphere. Due to the small amount of air to be removed from the printed cabin, it is assumed that the cabin pressure control is not significantly affected by this. The temperature level of the air-conditioned cabin air at around 30 ° to 40 ° Celsius is also adequate for the cooling task.
  • an electrical exhaust air fan 22 can optionally be activated.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The present invention relates to a method for monitoring a speed-controlled electric motor pump of a hydraulic circuit of an aircraft, wherein the electric motor pump comprises at least one electric motor having variable speed for driving the hydraulic pump and a hydraulic jacket cooling for cooling the electric motor pump is provided, through which the hydraulic medium conveyed by the pump flows, wherein the volume flow through the jacket cooling is detected for different motor speeds of the electric motor pump, in order to determine the volumetric efficiency of the pump.

Description

Verfahren zur Überwachung einer drehzahlgeregelten Elektromotorpumpe eines Hydraulikkreislaufs in einem Luftfahrzeug sowie Hydrauliksystem zur Verfahrens ausführung  Method for monitoring a speed-controlled electric motor pump of a hydraulic circuit in an aircraft and hydraulic system for executing the method
Die Erfindung betrifft ein Verfahren zur Überwachung einer drehzahlgeregelten Elektromotorpumpe eines Hydraulikkreislaufs in einem Luftfahrzeug, wobei die Elektromotorpumpe wenigstens einen Elektromotor mit variabler Drehzahl zum An trieb der Hydraulikpumpe umfasst und eine hydraulische Mantelkühlung zur Küh lung der Elektromotorpumpe vorgesehen ist, die durch das von der Pumpe geför derte Hydraulikmedium durchströmt wird. The invention relates to a method for monitoring a speed-controlled electric motor pump of a hydraulic circuit in an aircraft, wherein the electric motor pump comprises at least one electric motor with a variable speed for driving the hydraulic pump and a hydraulic jacket cooling is provided for cooling the electric motor pump, which is supported by the pump hydraulic medium is flowed through.
Aus dem Stand der Technik sind Hydrauliksysteme für Luftfahrzeuge bekannt, die wenigstens eine Elektromotorpumpe mit ungeregeltem Elektromotor umfassen. Solche Elektromotorpumpen sind rein hydromechanisch druckgeregelt und arbeiten mittels verstellbaren Axialkolbenpumpen mit variablem Schluckvolumen. Es ist heu te nicht möglich, derartige aus dem Stand der Technik bekannte Elektromotorpum pen richtig zu überwachen, da die wichtige Information des genau geförderten Durchflusses nicht ermittelt werden kann, wenn Informationen zur Drehzahl und Position der Drehscheibe der Axialkolbenpumpe fehlen. Aufgrund dieser Tatsache sind Elektromotorpumpen mit Pumpenfehlern behaftet, welche sich durch die Verschlechterung des volumetrischen Pumpenwirkungsgrads bemerkbar machen und heute nicht detektierbar sind. Wenn überhaupt kann eine Fehlfunktion der Pumpe nur im aktiven Betrieb festgestellt werden, was zur kriti schen Beeinflussung der Flugmission und damit zu großen ungeplanten finanziellen Aufwendungen für den Betreiber führen kann. Hydraulic systems for aircraft are known from the prior art, which comprise at least one electric motor pump with an uncontrolled electric motor. Such electric motor pumps are purely hydromechanically pressure-controlled and operate by means of adjustable axial piston pumps with a variable absorption volume. It is not possible today to properly monitor such electric motor pumps known from the prior art, since the important information of the precisely conveyed flow cannot be determined if information on the speed and position of the turntable of the axial piston pump is missing. Due to this fact, electric motor pumps are associated with pump errors, which are noticeable by the deterioration in the volumetric pump efficiency and are not detectable today. If anything, a malfunction of the pump can only be determined during active operation, which can critically influence the flight mission and thus lead to large unplanned financial expenses for the operator.
Vor diesem Hintergrund ist es Aufgabe der Erfindung, ein verbessertes Verfahren zur Überwachung einer Elektromotorpumpe bereitzustellen. Against this background, it is an object of the invention to provide an improved method for monitoring an electric motor pump.
Erfindungsgemäß wird vorgeschlagen, eine Elektromotorpumpe mit drehzahlvariab lem Elektromotor als Pumpenantrieb bereitzustellen. Die Elektromotorpumpe ist mit einer hydraulischen Mantelkühlung zur Kühlung der Elektromotorpumpe versehen. Für die Überwachung der Elektromotorpumpe wird vorgeschlagen, den Volumen strom durch die Mantelkühlung bei unterschiedlichen Motordrehzahlen der Elektro motorpumpe zu erfassen um basierend auf diesen Volumenstromwerten den volu metrischen Wirkungsgrad der Pumpe zu ermitteln. According to the invention, it is proposed to provide an electric motor pump with variable-speed electric motor as a pump drive. The electric motor pump is provided with a hydraulic jacket cooling for cooling the electric motor pump. For monitoring the electric motor pump, it is proposed to detect the volume flow through the jacket cooling at different motor speeds of the electric motor pump in order to determine the volumetric efficiency of the pump based on these volume flow values.
Anhand des volumetrischen Wirkungsgrades lässt sich die Pumpenfunktion über wachen und ein mögliches Fehlverhalten frühzeitig erkennen. Der volumetrische Wirkungsgrad ist definiert durch das Verhältnis des tatsächlich bereitgestellten Vo lumenstroms der Pumpe gegenüber dem theoretisch möglichen Volumenstrom der Pumpe. Eine Abnahme des Verhältnisses entspricht einer Verschlechterung des Pumpenwirkungsgrads, was ein Indiz für einen auftretenden Pumpenfehler sein kann. Based on the volumetric efficiency, the pump function can be monitored and a possible malfunction can be identified at an early stage. The volumetric efficiency is defined by the ratio of the actual volume flow of the pump to the theoretically possible volume flow of the pump. A decrease in the ratio corresponds to a deterioration in the pump efficiency, which can be an indication of a pump fault occurring.
Durch das erfindungsgemäße Verfahren wird eine automatische Überwachungs funktion der Elektromotorpumpe geschaffen, um den fehlerfreien Betrieb der Pum penfunktion zu gewährleisten. Die Elektromotorpumpe kann dabei idealerweise mit tels des sogenannten„continuous built-in test“ (CBIT) überwacht werden, welcher automatisiert den fehlerfreien Betriebszustand diagnostiziert und nur im Fehlerfall entsprechende Wartungsaktionen initiiert. Durch den CBIT können somit kostenin tensive geplante Wartungsvorgänge eingespart oder minimiert werden. An automatic monitoring function of the electric motor pump is created by the method according to the invention in order to ensure the fault-free operation of the pump function. The electric motor pump can ideally be monitored using the so-called "continuous built-in test" (CBIT), which automatically diagnoses the fault-free operating state and only in the event of a fault appropriate maintenance actions initiated. The CBIT thus saves or minimizes cost-intensive planned maintenance procedures.
Vor diesem Hintergrund ist es vorteilhaft, wenn der ermittelte volumetrische Wir kungsgrad der Pumpe ständig während des Flugbetriebs überwacht wird und bei einer auffälligen Änderung des Wirkungsgrades, beispielsweise einer Abweichung gegenüber einem Referenzwert oder dem Herausfallen des Wertes aus einem tole rierbaren Wertekorridor, eine Warnmeldung und/oder Wartungsaufforderung ange zeigt wird. Grundsätzlich ist es auch vorstellbar, dass bei einer entsprechend detek- tierten Abweichung zu einem Referenzwert auch eine geeignete Gegenmaßnahme eingeleitet wird. Against this background, it is advantageous if the determined volumetric efficiency of the pump is constantly monitored during flight operations and if there is a noticeable change in efficiency, e.g. a deviation from a reference value or if the value falls out of a tolerable value corridor, a warning message and / or maintenance request is displayed. In principle, it is also conceivable that a suitable countermeasure is also initiated in the event of a correspondingly detected deviation from a reference value.
Gemäß einer bevorzugten Ausführung der Erfindung wird der zu überwachende volumetrische Wirkungsgrad der Pumpe als das Verhältnis des gemessenen Volu menstroms durch die Mantelkühlung zum theoretischen Volumenstrom der Pumpe definiert. Der theoretische Volumenstrom ergibt sich aus dem Produkt der aktuellen Pumpen- bzw. Motordrehzahl und dem aktuellen Schluckvolumen der Pumpe. Ist die verbaute Hydraulikpumpe eine Konstantpumpe, so ist der theoretische Volu menstrom rein drehzahlabhängig. Die gefahrene Motordrehzahl ist dem System durch die Motorregelung bekannt. According to a preferred embodiment of the invention, the volumetric efficiency of the pump to be monitored is defined as the ratio of the measured volume flow through the jacket cooling to the theoretical volume flow of the pump. The theoretical volume flow results from the product of the current pump or motor speed and the current absorption volume of the pump. If the hydraulic pump installed is a constant pump, the theoretical volume flow is purely dependent on the speed. The engine speed is known to the system from the engine control.
Vorstellbar ist es beispielsweise, dass das Verfahren in einem gesonderten Test zyklus ausgeführt wird, bei diesem definierte Motordrehzahlen eingestellt und die entsprechenden volumetrischen Wirkungsgrade ermittelt werden. Alternativ oder zusätzlich ist es ebenso vorstellbar, dass eine kontinuierliche Überwachung wäh rend des regulären Flugbetriebs erfolgt, das heißt der volumetrische Wirkungsgrad der Pumpe wird kontinuierlich während des Betriebs der Hydraulik erfasst wird und überwacht. It is conceivable, for example, that the method is carried out in a separate test cycle, that defined engine speeds are set, and the corresponding volumetric efficiencies are determined. Alternatively or additionally, it is also conceivable that continuous monitoring takes place during normal flight operations, that is to say the volumetric efficiency of the pump is continuously recorded and monitored during the operation of the hydraulic system.
Die Erfassung des Volumenstroms durch die Mantelkühlung erfolgt unmittelbar durch eine geeignete Sensorik. Aufgrund der geforderten Robustheit der Sensoren für ein Luftfahrzeug ist die Verwendung eines Differenzdrucksensors bevorzugt. Ein solcher Sensor misst bspw. den über der Mantelkühlung abfallenden Differenz druck. Unter der Prämisse, dass die Mantelkühlung als kalibrierter Durchflusswider stand verstanden wird, kann unter Berücksichtigung der physikalischen Zusam menhänge bei hydraulischen Blenden der Volumenstrom durch die Mantelkühlung in Abhängigkeit des gemessenen Differenzdruckes errechnet werden. Weitere be nötigte Parameter, bspw. die Dichte und Temperatur des Hydraulikmediums sowie der hydraulische Widerstand der Mantelkühlung, liegen der das Verfahren ausfüh renden Steuerung vor. Insbesondere ein geeigneter Temperatursensor im Bereich der Mantelkühlung zur Erfassung der Mediumtemperatur ohnehin verbaut sein, um eine zu starke Erwärmung des Hydraulikmediums innerhalb des Kühlmantels zu detektieren. The volume flow through the jacket cooling is recorded directly by suitable sensors. Due to the required robustness of the sensors for an aircraft, the use of a differential pressure sensor is preferred. A Such a sensor measures, for example, the pressure drop across the jacket cooling. Under the premise that the jacket cooling is understood as a calibrated flow resistance, the volume flow through the jacket cooling can be calculated depending on the measured differential pressure, taking into account the physical interrelationships with hydraulic orifices. Further necessary parameters, for example the density and temperature of the hydraulic medium and the hydraulic resistance of the jacket cooling, are available to the control executing the method. In particular, a suitable temperature sensor in the area of the jacket cooling for detecting the medium temperature should be installed anyway in order to detect excessive heating of the hydraulic medium within the cooling jacket.
Üblicherweise wird die Mantelkühlung durch das Hydraulikmedium von der Nieder druckseite des Hydraulikkreislaufes durchströmt. The jacket cooling is usually flowed through by the hydraulic medium from the low pressure side of the hydraulic circuit.
Kommt die Elektromotorpumpe in einem dauerlaufenden Hydrauliksystem zum Ein satz, so wird eine Kühlung, insbesondere des Elektromotors, über die integrale Mantelkühlung erzielt. Gegebenenfalls ist jedoch ebenfalls eine Kühlung des Hyd raulikmediums notwendig. Empfehlenswert ist die Integration eines geeigneten Wärmetauschers in den Hydraulikkreis, insbesondere in den Niederdruckbereich, um das durchströmende Hydraulikmedium mittels passender Wärmesenke zu küh len. If the electric motor pump is used in a continuously running hydraulic system, cooling, in particular of the electric motor, is achieved via the integral jacket cooling. However, cooling of the hydaulic medium may also be necessary. It is advisable to integrate a suitable heat exchanger in the hydraulic circuit, especially in the low-pressure area, in order to cool the hydraulic medium flowing through using a suitable heat sink.
Eine geeignete Wärmesenke kann beispielsweise der Kraftstofftank des Luftfahr zeuges sein. Da der Kraftstofftank jedoch nur im Bereich der Tragflächen als Wär mesenke zur Verfügung steht, ist alternativ der Einsatz eines Luft-Hydraulik- Wärmetauschers sinnvoll. Als Kühlmedium könnte hier atmosphärische Luft durch den Wärmetauscher geleitet werden. Da eine solche Maßnahme jedoch in der Re gel eine Stauluftöffnung der Flugzeugaussenhaut erfordert und dies im Hinblick auf das Vermeiden von Strömungsverlusten nachteilig ist, besteht ein alternativer, be vorzugter Ansatz darin, stattdessen Luft aus dem bedruckten Bereich des Luftfahr- zeuges, bspw. aus der Flugzeugkabine, durch den Wärmetauscher als Kühlmedium strömen zu lassen. A suitable heat sink can be, for example, the fuel tank of the aircraft. However, since the fuel tank is only available as a heat sink in the area of the wings, the use of an air-hydraulic heat exchanger is useful. Atmospheric air could be passed through the heat exchanger as the cooling medium. However, since such a measure generally requires a ram air opening in the aircraft outer skin and this is disadvantageous in terms of avoiding flow losses, an alternative, preferred approach is to use air from the printed area of the aircraft instead. Stuff, for example from the aircraft cabin, to flow through the heat exchanger as a cooling medium.
Neben dem erfindungsgemäßen Verfahren betrifft die vorliegende Erfindung zudem ein Hydrauliksystem eines Luftfahrzeuges mit wenigstens einer drehzahlgeregelten Elektromotorpumpe mit hydraulischer Mantelkühlung. Darüber hinaus umfasst das Hydrauliksystem eine Sensorik zur unmittelbaren oder mittelbaren Volumenstrom messung des Hydraulikflusses durch die Mantelkühlung sowie wenigstens eine Steuerung zur Ausführung des erfindungsgemäßen Verfahrens. In addition to the method according to the invention, the present invention also relates to a hydraulic system of an aircraft with at least one speed-controlled electric motor pump with hydraulic jacket cooling. In addition, the hydraulic system comprises a sensor system for direct or indirect volume flow measurement of the hydraulic flow through the jacket cooling and at least one controller for executing the method according to the invention.
Das Hydrauliksystem zeichnet sich offensichtlich durch dieselben Vorteile und Ei genschaften aus, wie sie bereits vorstehend anhand des erfindungsgemäßen Ver fahrens aufgezeigt wurden. Auf eine wiederholende Beschreibung wird aus diesem Grund verzichtet. The hydraulic system is obviously characterized by the same advantages and egg properties, as have already been shown above using the method according to the invention. For this reason, a repetitive description is omitted.
Gemäß einer besonders bevorzugten Ausführungsform der Erfindung ist die Elekt romotorpumpe in ein Gehäuse mit integrierter Mantelkühlung eingefasst. Neben dem Elektromotor und der Hydraulikpumpe ist zudem die entsprechende Sensorik zur Durchflussmessung als auch eine entsprechende Steuerung zur Verfahrens ausführung vorhanden. According to a particularly preferred embodiment of the invention, the electric motor pump is enclosed in a housing with integrated jacket cooling. In addition to the electric motor and the hydraulic pump, the corresponding sensors for flow measurement as well as a corresponding control for process execution are also available.
Für die Kühlung des Hydraulikmediums innerhalb des Hydrauliksystems ist vor zugsweise wenigstens ein Hydraulik-Luft-Wärmetauscher vorgesehen, wobei dieser sinnvollerweise im Niederdruckbereich des Hydraulikkreislaufs angeordnet ist. Über einen entsprechenden Luftkanal kann Kabinenluft durch den Wärmetauscher strö men. Aufgrund des Druckunterschiedes im Flugbetrieb erfordert dies keine zusätz lichen Strömungsmaschinen, der Druckunterschied sorgt für eine ausreichende Strömungsgeschwindigkeit durch den Wärmetauscher. For cooling the hydraulic medium within the hydraulic system, at least one hydraulic-air heat exchanger is preferably provided, which is expediently arranged in the low-pressure region of the hydraulic circuit. Cabin air can flow through the heat exchanger via an appropriate air duct. Due to the pressure difference in flight operations, this does not require any additional flow machines, the pressure difference ensures a sufficient flow speed through the heat exchanger.
Bedarfsweise kann der Luftstrom aus dem bedruckten Kabinenbereich durch we nigstens ein Ventil gesteuert sein, um bspw. eine temperaturabhängige Kühlung auszuführen. Erst bei Übersteigen eines maximalen Temperaturwertes des Hydrau likmediums wird das Ventil geöffnet und eine Kühlwirkung erzeugt. If necessary, the air flow from the printed cabin area can be controlled by at least one valve, for example temperature-dependent cooling to execute. The valve is only opened and a cooling effect is generated when the maximum temperature value of the hydraulic medium is exceeded.
Optional kann wenigstens ein Lüfter in Strömungsrichtung vor und/oder nach dem Wärmetauscher angeordnet sein, um die Förderung der Abluft in die Atmosphäre zu unterstützen. Ein solcher Lüfter ist insbesondere dann von Vorteil, wenn kein oder nur geringer Druckunterschied zwischen Kabinendruck und Atmosphäre vor liegt, so beispielsweise wenn das Luftfahrzeug auf dem Boden steht. Optionally, at least one fan can be arranged in the flow direction before and / or after the heat exchanger in order to support the conveying of the exhaust air into the atmosphere. Such a fan is particularly advantageous when there is little or no pressure difference between the cabin pressure and the atmosphere, for example when the aircraft is on the ground.
Neben dem Hydrauliksystem betrifft die Erfindung weiterhin ein Luftfahrzeug mit einem entsprechenden Hydrauliksystem gemäß der Erfindung, sodass sich auch bezüglich des Luftfahrzeuges dieselben Vorteile und Eigenschaften ergeben. In addition to the hydraulic system, the invention further relates to an aircraft with a corresponding hydraulic system according to the invention, so that the same advantages and properties also result with respect to the aircraft.
Denkbar ist es, dass das Hydrauliksystem ein isoliertes Hydrauliksystem zur pri mären Flugsteuerung ist, beispielsweise zur Steuerung des Leitwerks eines Luft fahrzeuges. Das entsprechende Hydrauliksystem ist hierbei im unbedruckten Be reich untergebracht, idealerweise im Heck bzw. hecknahen Bereich des Luftfahr zeuges. It is conceivable that the hydraulic system is an isolated hydraulic system for primary flight control, for example for controlling the tail unit of an aircraft. The corresponding hydraulic system is housed in the unprinted area, ideally in the rear or near the rear of the aircraft.
Weitere Vorteile und Eigenschaften der Erfindung sollen nachfolgend anhand eines in den Figuren dargestellten Ausführungsbeispiels näher erläutert werden. Es zei gen: Further advantages and properties of the invention will be explained in more detail below on the basis of an exemplary embodiment shown in the figures. Show it:
Fig. 1 : ein Diagramm zur Verdeutlichung des Zusammenhangs zwischen Volu menstrom und volumetrischen Pumpenwirkungsgrad, 1: a diagram to illustrate the relationship between volumetric flow and volumetric pump efficiency,
Fig. 2: den erfindungsgemäßen Hydraulikkreislauf für eine primäre Flugsteue rung gemäß der vorliegenden Erfindung, 2: the hydraulic circuit according to the invention for a primary flight control according to the present invention,
Fig. 3: eine modifizierte Ausführung des erfindungsgemäßen Hydraulikkreis laufs gemäß Figur 2. Figur 2 zeigt den Aufbau des erfindungsgemäßen Hydrauliksystems. Die Elektro- motorpumpe 10 besteht aus einem drehzahlregelbaren Motor M, der die Konstant druckpumpe FDP antreibt. Ein entsprechender Steuerungscomputer MCE dient unter anderem zur Drehzahlregelung des Motors M. 3: a modified version of the hydraulic circuit according to the invention according to FIG. 2. Figure 2 shows the structure of the hydraulic system according to the invention. The electric motor pump 10 consists of a speed-controllable motor M which drives the constant pressure pump FDP. A corresponding control computer MCE is used, among other things, to regulate the speed of the motor M.
Die Elektromotorpumpe 10 ist integraler Bestandteil eines Flydrauliksystems für die primäre Flugsteuerung eines Luftfahrzeuges. Der Flochdruckausgang der Kon stantpumpe FDP ist über ein Rückschlagventil 2 und einen Hochdruckfilter 3 mit wenigstens einem hydraulischen Verbraucher 4, insbesondere Hydraulikaktor, für die mechanische Betätigung der Steuerflächen verbunden. Vom Verbraucher 4 führt die Niederdruckseite über einen Niederdruckfilter 5 zurück zum Hydrauliktank T, aus diesem die Konstantdruckpumpe FDP Hydraulikmedium ansaugt. Zudem sind zwischen Rückschlagventil 2 und Hochdruckfilter 3 ein Drucksensor 7 sowie ein hydraulischer Speicher angeordnet. Das Überlastventil 6 verbindet die Hoch- und Niederdruckseite parallel zum Verbraucher 4. Darüber hinaus werden optional die abfallenden Differenzdrücke über den Filtern 3, 5 erfasst, um den Verschmut zungsgrad des Filters zu messen. The electric motor pump 10 is an integral part of a fly hydraulic system for the primary flight control of an aircraft. The hole pressure output of the constant pressure pump FDP is connected via a check valve 2 and a high pressure filter 3 to at least one hydraulic consumer 4, in particular hydraulic actuator, for the mechanical actuation of the control surfaces. The low-pressure side leads from the consumer 4 via a low-pressure filter 5 back to the hydraulic tank T, from which the constant pressure pump FDP sucks in hydraulic medium. In addition, a pressure sensor 7 and a hydraulic accumulator are arranged between check valve 2 and high-pressure filter 3. The overload valve 6 connects the high and low pressure side parallel to the consumer 4. In addition, the falling differential pressures over the filters 3, 5 are optionally recorded in order to measure the degree of contamination of the filter.
Die Steuerung MCE, der Motor M sowie die Konstantdruckpumpe FDP bilden eine Baugruppe und sind gemeinsam in einem Gehäuse untergebracht. Das Gehäuse ist mit einer hydraulischen Mantelkühlung ausgestattet, die einen Eingangs- und Ausgangsanschluss aufweist, die über in die Gehäusewandung eingebettete Kühl kanäle miteinander verbunden sind. Der Eingang des Kühlmantels steht mit dem Filter 5 in Verbindung während der Ausgang über Verbindungsleitungen im Tank T mündet. Das durch die Kanalstruktur des Gehäuses durchströmende Hydrauliköl sorgt für eine ausreichende Kühlung insbesondere des integralen Elektromotors M. The MCE control unit, the M motor and the FDP constant pressure pump form a module and are housed together in one housing. The housing is equipped with hydraulic jacket cooling, which has an input and output connection, which are connected to each other via cooling channels embedded in the housing wall. The inlet of the cooling jacket is connected to the filter 5, while the outlet opens into the tank T via connecting lines. The hydraulic oil flowing through the channel structure of the housing ensures adequate cooling, in particular of the integral electric motor M.
Mittels des Differenzdrucksensors 11 wird der abfallende Druck über der Mantel kühlung der Elektromotorpumpe 10 erfasst. Ein ebenfalls vorgesehener Tempera tursensor 12 erfasst die Temperatur des Hydraulikmediums am Ausgang der Man telkühlung. Zur Überwachung der Elektromotorpumpe 10 ist in der Steuerung MCE ein Verfah ren implementiert, das kontinuierlich den volumetrischen Wirkungsgrad der Pumpe FDP ermittelt. Der volumetrische Wirkungsgrad hR , Vo/ ist durch das Verhältnis des tatsächlichen Durchflusses Qeff ( Qgemessen ) zum theoretisch geförderten Durchfluss Qth der Pumpe FDP definiert. Letzterer ist ergibt sich aus dem Produkt der aktuellen Drehzahl n und des Schluckvolumens \/der Pumpe FDP. By means of the differential pressure sensor 11, the falling pressure over the jacket cooling of the electric motor pump 10 is detected. A likewise provided temperature sensor 12 detects the temperature of the hydraulic medium at the outlet of the cooling device. To monitor the electric motor pump 10, a process is implemented in the MCE control which continuously determines the volumetric efficiency of the pump FDP. The volumetric efficiency h R, Vo / is defined by the ratio of the actual flow Q eff (Q measured) to the theoretically promoted flow Q th of the pump FDP. The latter is the product of the current speed n and the swallowing volume \ / the pump FDP.
Für die Überwachung des volumetrischen Wirkungsgrades hR, voi der Pumpe FDP wird ein entsprechender Korridor durch ein Maximal- und Minimallimit des volumet rischen Wirkungsgrades hR , voi definiert, wie dies in Figur 1 zu sehen ist. Überschrei tet der erfasste volumetrische Wirkungsgrad hR , Voi einen entsprechenden Grenzbe reich, wird von der Steuerung MCE eine Warnmeldung erzeugt und angezeigt, ge gebenenfalls in Kombination mit einer Aufforderung zur Durchführung von War- tungs- bzw. Reparaturarbeiten am Hydrauliksystem. For monitoring the volumetric efficiency h R, v oi of the pump FDP, a corresponding corridor is defined by a maximum and minimum limit of the volumetric efficiency h R, v oi , as can be seen in FIG. 1. If the recorded volumetric efficiency h R, Voi exceeds a corresponding limit range, the MCE control unit generates and displays a warning message, possibly in combination with a request to carry out maintenance or repair work on the hydraulic system.
Die Ermittlung des benötigten tatsächlichen Durchflusses Qeff kann auf unterschied liche Art und Weise erfolgen, entweder unmittelbar über einen Durchflusssensor mit einem beliebigen physikalischen Funktionsprinzip (kalorimetrisch, Ultraschall, Flü gelrad) oder bevorzugt, wie im Ausführungsbeispiel der Figur 2 gezeigt, mittels ei nes kalibrierten Durchflusswiderstand in Verbindung mit einer Differenzdruckmes sung und den physikalischen Parametern Differenzdruck Dr, Fluidtemperatur TFiUid, Fluiddruck pFiUid sowie Dichte p des Hydraulikmediums . The determination of the actual flow rate Q eff required can be carried out in different ways, either directly via a flow sensor with any physical functional principle (calorimetric, ultrasound, paddlewheel) or, as shown in the exemplary embodiment in FIG. 2, by means of a calibrated one Flow resistance in connection with a differential pressure measurement and the physical parameters differential pressure Dr, fluid temperature T FiUid, fluid pressure p FiUid and density p of the hydraulic medium .
Erfindungsgemäß wird der entsprechende Durchfluss Qeff im Bereich der hydrauli schen Mantelkühlung bestimmt, wobei die Mantelkühlung hier als kalibrierter großer Durchflusswiderstand dient. Mittels des Differenzdrucksensors 11 wird der Diffe renzdruck Dr über der Mantelkühlung laufend erfasst und unter Berücksichtigung der physikalischen Zusammenhänge bei hydraulischen Blenden der entsprechende Durchfluss Qeffgemäß: According to the invention, the corresponding flow rate Q eff is determined in the area of the hydraulic jacket cooling, the jacket cooling serving here as a calibrated large flow resistance. The differential pressure sensor 11 continuously detects the differential pressure Dr above the jacket cooling and, taking into account the physical relationships with hydraulic orifices, the corresponding flow rate Q eff in accordance with:
Figure imgf000010_0001
bestimmt. Die Parameter für die Berechnung der Fluiddichte p sind in einem ent sprechenden Hydrauliksystem normalerweise vorhanden, da immer der Ausgangs druck der Pumpe FDP für die Regelung gemessen wird, hier mittels des Sensors 7, und üblicherweise auch die Fluidtemperatur im Bereich der Mantelkühlung gemes sen wird, hier mittels des Sensors 12. Die Daten des Drucksensors 7, des Diffe renzdrucksensors 11 , des Temperatursensors 12 werden der Steuerung MCE lau fend übermittelt, diese dann den berechneten volumetrischen Wirkungsgrad der Pumpe FDP laufend gegen die Grenzkurven der Figur 1 vergleichen kann. Die Sig nalleitungen sind in der Figur 3 gezeigt, sind jedoch im Beispiel der Figur 2 iden tisch verwirklicht.
Figure imgf000010_0001
certainly. The parameters for the calculation of the fluid density p are normally present in a corresponding hydraulic system, since the output pressure of the pump FDP is always measured for the control, here by means of the sensor 7, and usually the fluid temperature in the area of the jacket cooling is measured, here by means of the sensor 12. The data from the pressure sensor 7, the differential pressure sensor 11, the temperature sensor 12 are continuously transmitted to the control MCE, which can then continuously compare the calculated volumetric efficiency of the pump FDP against the limit curves in FIG. The signal lines are shown in FIG. 3, but are implemented identically in the example in FIG. 2.
Die Ermittlung des real geförderten Durchflusses Qeff kann kontinuierlich mit einem CBIT erfolgen, da das zurückfließende Hydrauliköl der Niederdruckseite stets voll ständig über den Kühlmantel der Elektromotorpumpe 10 zurückfließt, sobald diese in Betrieb ist. Diese Vorgehensweise ist prinzipiell unabhängig von der Betriebswei se der Pumpe 10, d.h. für unidirektionalen oder auch für bidirektionalen Betrieb der Elektromotorpumpe 10 einsetzbar. The determination of the actually conveyed flow rate Q eff can be carried out continuously with a CBIT, since the hydraulic oil flowing back on the low-pressure side always flows back completely and continuously via the cooling jacket of the electric motor pump 10 as soon as it is in operation. In principle, this procedure can be used independently of the operating mode of the pump 10, ie for unidirectional or also for bidirectional operation of the electric motor pump 10.
Ein weiterer Aspekt der Erfindung besteht darin, dass aufgrund des Dauerbetriebs des Hydrauliksystems ggf. für eine Kühlung des Hydraulikmediums gesorgt werden muss. Dies gilt insbesondere dann, wenn das Hydrauliksystem ein isoliertes Sys tem für die primäre Flugsteuerung ist, so beispielsweise zur Steuerung des Flug zeugleitwerkes im Heckbereich des Flugzeuges. Da dort wie bei anderen Hydrau liksystemen keine adäquate Wärmesenke in Form des Kerosintanks zur Verfügung steht, muss hier auf eine Alternative zurückgegriffen werden. Eine zusätzliche Stauluftöffnung zur Nutzung atmosphärischer Kühlluft ist aus strömungstechni schen Gründen zu vermeiden. Another aspect of the invention is that due to the continuous operation of the hydraulic system, cooling of the hydraulic medium may have to be ensured. This applies in particular when the hydraulic system is an isolated system for the primary flight control, for example for the control of the flight control unit in the rear area of the aircraft. As there is no adequate heat sink in the form of the kerosene tank available as with other hydraulic systems, an alternative must be used here. An additional ram air opening for the use of atmospheric cooling air should be avoided for fluidic reasons.
Vor diesem Hintergrund wird das System der Figur 2 im Niederdruckbereich des Hydraulikkreises um wenigstens einen Hydraulik-Luft-Wärmetauscher 20 erweitert, alle sonstigen Komponenten sind identisch zur Ausführung der Figur 2. Die not- wendige Kühlluft wird bei Bedarf über das Ventil 21 aus der Flugzeugkabine ent nommen. Aufgrund des im Flugbetrieb vorliegenden Druckunterschieds zwischen Kabinendruck und Atmosphärendruck strömt die Kabinenluft durch den Wärmetau scher 20, von diesem sie an die Atmosphäre abgegeben wird. Aufgrund der gerin gen abzuführenden Menge an Luft aus der bedruckten Kabine wird angenommen, dass die Kabinendruckregelung hiervon nicht wesentlich beeinflusst wird. Auch ist das Temperaturniveau der klimatisierten Kabinenluft mit ca. 30° bis 40° Celsius adäquat für die Kühlungsaufgabe. Against this background, the system in FIG. 2 is expanded in the low-pressure region of the hydraulic circuit by at least one hydraulic-air heat exchanger 20; all other components are identical to the embodiment in FIG. Agile cooling air is removed from the aircraft cabin via the valve 21 if necessary. Due to the pressure difference between cabin pressure and atmospheric pressure present in flight operation, the cabin air flows through the heat exchanger 20, from which it is released into the atmosphere. Due to the small amount of air to be removed from the printed cabin, it is assumed that the cabin pressure control is not significantly affected by this. The temperature level of the air-conditioned cabin air at around 30 ° to 40 ° Celsius is also adequate for the cooling task.
Um das hydraulische System auch im Bodenbetrieb zu kühlen, kann optional ein elektrischer Abluftventilator 22 aktiviert werden. In order to cool the hydraulic system even during ground operation, an electrical exhaust air fan 22 can optionally be activated.

Claims

Patentansprüche Claims
1. Verfahren zur Überwachung einer drehzahlgeregelten Elektromotorpumpe eines Hydraulikkreislaufs in einem Luftfahrzeug, wobei die Elektromotorpum pe wenigstens einen Elektromotor (M) mit variabler Drehzahl zum Antrieb der Hydraulikpumpe (2) umfasst und eine hydraulische Mantelkühlung zur Küh lung der Elektromotorpumpe vorgesehen ist, durch die das von der Pumpe geförderte Hydraulikmedium durchströmt, dadurch gekennzeichnet, dass der Volumenstrom durch die Mantelkühlung für unterschiedliche Motordreh zahlen der Elektromotorpumpe erfasst wird, um den volumetrischen Wir kungsgrad der Pumpe zu ermitteln, wobei der Volumenstrom durch die Man telkühlung auf Grundlage des über der Mantelkühlung über einen Differenz drucksensor erfassten Differenzdruckes berechnet wird. 1. A method for monitoring a speed-controlled electric motor pump of a hydraulic circuit in an aircraft, the electric motor pump comprising at least one electric motor (M) with variable speed for driving the hydraulic pump (2) and hydraulic jacket cooling for cooling the electric motor pump is provided, by which the Hydraulic medium delivered by the pump flows through, characterized in that the volume flow through the jacket cooling is recorded for different motor speeds of the electric motor pump in order to determine the volumetric efficiency of the pump, the volume flow through the jacket cooling based on the jacket cooling via a Differential pressure sensor detected differential pressure is calculated.
2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, dass der ermittelte vo lumetrische Wirkungsgrad der Pumpe überwacht wird und bei einer auffälligen Änderung eine Warnmeldung und/oder Wartungsaufforderung angezeigt und/oder eine Gegenmaßnahme eingeleitet wird, wobei die Überwachung vorzugsweise durch Vergleich des volumetrischen Wirkungsgrades gegen ei nen oberen und/oder unteren Grenzwert erfolgt. 2. The method according to claim 1, characterized in that the determined volumetric efficiency of the pump is monitored and in the event of a conspicuous Change a warning message and / or maintenance request is displayed and / or a countermeasure is initiated, the monitoring preferably being carried out by comparing the volumetric efficiency against an upper and / or lower limit value.
3. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekenn zeichnet, dass der volumetrische Wirkungsgrad der Pumpe durch das Ver hältnis von gemessenem Volumenstrom durch die Mantelkühlung zum theore tischen Volumenstrom der Pumpe bestimmt wird, wobei sich der theoretische Volumenstrom aus dem Produkt aus aktueller Pumpen-/Motordrehzahl und aktuellem Schluckvolumen der Pumpe ergibt. 3. The method according to any one of the preceding claims, characterized in that the volumetric efficiency of the pump is determined by the ratio of measured volume flow through the jacket cooling to the theoretical volume flow of the pump, the theoretical volume flow resulting from the product of current pump / Motor speed and current absorption volume of the pump results.
4. Verfahren nach einem der vorangehenden Ansprüche, dadurch gekennzeich net, dass die Temperatur des Hydraulikmediums im Bereich der Mantelküh lung erfasst wird, insbesondere durch einen Temperatursensor zur Überwa chung von Übertemperaturen des Hydraulikmediums, und für die Berechnung des Volumenstroms durch die Mantelkühlung berücksichtigt wird. 4. The method according to any one of the preceding claims, characterized in that the temperature of the hydraulic medium is detected in the jacket cooling area, in particular by a temperature sensor for monitoring excess temperatures of the hydraulic medium, and is taken into account for the calculation of the volume flow through the jacket cooling.
5. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekenn zeichnet, dass Hydraulikmedium von der Niederdruckseite des Hydraulikkreis laufs durch die Mantelkühlung strömt. 5. The method according to any one of the preceding claims, characterized in that hydraulic medium flows from the low pressure side of the hydraulic circuit through the jacket cooling.
6. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekenn zeichnet, dass das Hydraulikmedium des Hydraulikkreislaufs durch die Kabi nenluft des Luftfahrzeuges gekühlt wird, insbesondere mittels eines im Nieder ruckbereich angeordneten Luft-Hydraulik-Wärmetauschers. 6. The method according to any one of the preceding claims, characterized in that the hydraulic medium of the hydraulic circuit is cooled by the cabin air of the aircraft, in particular by means of an air-hydraulic heat exchanger arranged in the low pressure region.
7. Hydrauliksystem eines Luftfahrzeuges umfassend wenigstens eine drehzahl geregelte Elektromotorpumpe mit hydraulischer Mantelkühlung, einer Senso rik zur unmittelbaren oder mittelbaren Volumenstrommessung durch die Man telkühlung sowie wenigstens einer Steuerung zur Durchführung des Verfah rens gemäß einem der vorhergehenden Ansprüche. 7. Hydraulic system of an aircraft comprising at least one speed-controlled electric motor pump with hydraulic jacket cooling, a sensor technology for direct or indirect volume flow measurement through the man cooling and at least one controller for carrying out the method according to one of the preceding claims.
8. Hydrauliksystem nach Anspruch 7, dadurch gekennzeichnet, dass die Elekt- romotorpumpe ein Gehäuse mit Mantelkühlung umfasst, in das wenigstens eine Hydraulikpumpe, wenigstens ein die Pumpe antreibender drehzahlgere gelter Elektromotor, eine Sensorik zur Durchflussmessung durch die Mantel kühlung und wenigstens eine Steuerung zur Ausführung des Verfahrens ge mäß den Ansprüchen 1 bis 8 integriert sind. 8. Hydraulic system according to claim 7, characterized in that the electric motor pump comprises a housing with jacket cooling, in which at least one hydraulic pump, at least one speed-driven, controlled electric motor, a sensor system for flow measurement through the jacket cooling and at least one controller for execution of the method are integrated according to claims 1 to 8.
9. Hydrauliksystem nach einem der Ansprüche 7 und 8, dadurch gekennzeich net, dass ein Hydraulik-Luft-Wärmetauscher in den Hydraulikkreis integriert ist, insbesondere in den Niederdruckbereich, und über einen Luftkanal Kabi nenluft durch den Wärmetauscher zur Kühlung des Hydraulikmediums leitbar ist. 9. Hydraulic system according to one of claims 7 and 8, characterized in that a hydraulic-air heat exchanger is integrated in the hydraulic circuit, in particular in the low pressure region, and neni air can be conducted through the heat exchanger for cooling the hydraulic medium via an air duct.
10. Hydrauliksystem nach Anspruch 9, dadurch gekennzeichnet, dass der Luft strom aus dem bedruckten Kabinenbereich durch wenigstens ein Ventil steu erbar ist. 10. Hydraulic system according to claim 9, characterized in that the air flow from the printed cabin area can be controlled by at least one valve.
11. Hydrauliksystem nach einem der Ansprüche 9 und 10, dadurch gekennzeich net, dass wenigstens ein Lüfter zur Förderung der Abluft aus dem Wärmetau scher vorgesehen ist. 11. Hydraulic system according to one of claims 9 and 10, characterized in that at least one fan is provided to promote the exhaust air from the heat exchanger shear.
12. Luftfahrzeug mit einem Hydrauliksystem nach einem der vorhergehenden An sprüche 7 bis 11. 12. Aircraft with a hydraulic system according to one of the preceding claims 7 to 11.
13. Luftfahrzeug nach Anspruch 12, dadurch gekennzeichnet, dass das Hydrau liksystem im unbedruckten Bereich des Hecks des Luftfahrzeuges verbaut ist und zur primären Flugsteuerung dient, inbesondere zur Betätigung des Leit werkes. 13. Aircraft according to claim 12, characterized in that the hydraulic liksystem is installed in the unprinted area of the rear of the aircraft and is used for primary flight control, in particular for actuating the control unit.
PCT/EP2019/080030 2018-11-20 2019-11-04 Method for monitoring a speed-controlled electric motor pump of a hydraulic circuit in an aircraft and a hydraulic system for carrying out the method WO2020104174A1 (en)

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