EP3212928A1

EP3212928A1 - Fluid and fuel pump system

Info

Publication number: EP3212928A1
Application number: EP15781940.0A
Authority: EP
Inventors: Gerald BEHRENDT
Original assignee: Continental Automotive GmbH
Current assignee: Continental Automotive GmbH
Priority date: 2014-10-27
Filing date: 2015-10-20
Publication date: 2017-09-06
Also published as: DE102014221871A1; WO2016066472A1

Abstract

The invention relates to a fluid pump system (10), comprising a first fluid pump assembly (100), which is designed to receive a fluid via a first fluid supply line (114) and to output said fluid via a first fluid discharge line (116), and a second fluid pump assembly (200), which is designed to receive a fluid via a second fluid supply line (214) and to output said fluid via a second fluid discharge line (216). The first fluid pump assembly (100) has: a first pump device (105), which has a first pump unit (110) and a first pump motor (120), wherein the first pump motor is coupled to the first pump unit (110) in such a way that the first pump motor can drive the first pump unit; an energy source (130) in order to supply the first pump motor (120) with current; and a control unit (140), which is designed to read in a setpoint value for a fluid pressure to be supplied by the first pump device (105) and to determine a current intensity for the first pump motor (120) that corresponds to the setpoint value for the fluid pressure to be supplied for a specified pump motor rotational speed and to control the energy source (130) in such a way that the energy source outputs the determined current intensity to the first pump motor (120).

Description

description

Fluid and fuel pumping system The invention relates to a fluid pump system, a method of operating a fluid pumping system, and a vehicle with egg ^¬ nem such a fluid pump system.

Fluid pumps in the form of fuel pumps are commonly used in vehicles to pump a fuel, which is usually held ^¬ as fluid, from a fuel tank or fuel tank to a drive unit, which is usually designed in this case as an internal combustion engine to pump or to transport.

As fuel pumps while all Pum ^¬ groups come into question, which are designed to pump a fluid. A fuel pump for a vehicle is usually designed to deliver the fuel to the internal combustion engine with a predetermined or specifiable fuel pressure. Furthermore, a fuel pump is usually designed to provide a vorgebba ^¬ ren volume flow of the fuel, so a certain amount of fuel per unit time (usually in liters per hour).

Conventional fuel pumps have a pump stage, which can be referred to as a pump unit and a Pum ^¬ penmotor on. The pump motor is connected to the pump stage so gekop ^¬ pelt that the motor rotates the pump level in motion, and is pumped through this movement of the fuel. The geliefer ^¬ displaced flow of the fuel pump is usually proportional to the speed of the pump motor.

The pump stage is coupled to the fuel tank via a fuel supply line or is located in the fuel container and is coupled via a fuel discharge with the combus ^¬ tion motor. In order to achieve a predeterminable fuel pressure in the fuel discharge, a pressure sensor is usually arranged so that the fuel pressure is detected. The detected fuel pressure is used to vary the rotational speed of the pump motor ^¬ when the fuel pressure is to be changed fabric dissipation in the motor.

Typically, a variable-speed system, is used as the pump apparatus since the rotational speed of the pump motor is proportio nal ^¬ to the volume flow. The speed is increased at a constant flow rate, so that the pressure increases in the power ^¬ material derivative. The behavior in individual cases depends on the so-called pressure stiffness of the pump stage.

It can be regarded as an object of the invention to provide a fluid pump system and a method for controlling a fluid pump system, which are characterized by a simplified actuation of the fluid pump system and a more economically favorable conversion.

According to a first aspect of the invention, a fluid pump system is specified. The fluid pump system comprises a first fluid pump arrangement, which is designed to receive a fluid through a first fluid supply line and line via a first Fluidab- dispense, and a second fluid pump assembly which is adapted to increase a fluid through a second fluid supply line for ^¬ and via a second Dispense fluid drain on. The first fluid pump assembly has a first Pumpenvorrich ^¬ tung, a power source and a control unit. The first pump device has a first pump unit and a ^¬ ers th pump motor, said first pump motor is coupled to the first pump unit so that the first pump motor can drive the first pump unit. The energy source is led out ^¬ to supply the first pump motor with power. The Control unit is configured to read in a target value for a to be supplied by the first pump device fluid pressure and at a predetermined pump motor speed to the target ^¬ value for the information to supply fluid pressure to determine the corresponding current intensity for the first pump motor and thus to control the source of energy, that these are the current determined outputs to the first pump motor.

Such a fluid system can also be described as a multi-pump system ^¬ net. In particular, the first and second fluid pump ^¬ nanordnung are connected in parallel to each other and are operated synchronously. Alternatively, the two fluid pump arrangements can also be connected in series, ie, one fluid pump arrangement is connected downstream of the other fluid pump arrangement. To prevent to ver ^¬ that to impact the fluid pump assembly due to differing ^¬ cher tolerances and behavior, which can lead to uneven pumping behavior negatively to the pumping action of the fluid pump system, the fluid pump system is configured so that both fluid pump assemblies a äquiva ^¬ lente amount of fluid promote, so have a substantially equal volume flow of the fluid in the respective fluid discharge on ^¬ . It should therefore be prevented in particular that the pumps deliver a different volume flow, z. B. 20 liters / hour, the first fluid pump assembly and 100 liters / Stun ^¬ de the second fluid pump assembly, since in such a case in a parallel operation of the two fluid pump assemblies, the pumping power from a fluid pump assembly essentially runs into the void.

The first fluid pump arrangement is constructed so that it provided a waiver of a pressure sensor in the fluid discharge ^¬ light. The adaptation of the fluid pressure in the fluid discharge he ^¬ follows via an adjustment of the pump current and the rotational ^¬ number of the pump motor. By eliminating the pressure sensor, fluid pump systems can be constructed more economically. It should be noted that the fluid pump system may also comprise more than two fluid pump assemblies, so that a plurality of fluid pump assemblies or in parallel or in mixed forms successively (parallel connection of series circuits, or vice versa ^¬) are connected.

The pump motor may be, for example, a

DC motor or act on a synchronous motor, the latter example, in the embodiment as a permanent magnet motor with, for example, permanent magnet rotor, which is operated with three-phase current ^¬ ben.

The fluid pump system can be, for example, a system for pumping fuel for a vehicle to act a Hyd ^¬ raulikpumpe or to a coolant pump for a coolant circuit ^¬ run.

It should be noted that a reference to the "fluid pressure" below always refers to the fluid pressure in the corresponding ^¬ the first or second fluid discharge, unless it is ex ^¬ plicitly named any of this to the contrary.

The setpoint for the fluid pressure can be specified by an external unit, for. B. from an internal combustion engine or a component of the internal combustion engine, such as. As an engine control unit or an exhaust gas control unit, which is supplied by the fluid pump unit with fluid or from another unit in a vehicle.

The energy source is in particular designed to output a specifiable current to the pump motor. In the Energiequel ^¬ le is in one embodiment a Stromquel ^¬ le. The pump device can have a rotational speed detection unit ^¬ which is performed to determine the speed of the pump motor and pass on request, in particular to the control unit.

The control unit and the pump device may be spatially separated from each other and mounted, for example, in a vehicle as separate mounting units. The communication or data transmission between pump device and Steuerein ^¬ unit can via a data transmission path, z. B. via a bus system such as CAN done.

According to one embodiment of the invention, the first fluid drain is coupled to the second fluid drainage such that these two fluid drainages open into a common drainage. In this case, the first fluid pump arrangement is coupled via an ers ^¬ tes check valve with the common derivative and the second fluid pump assembly is coupled via a second return ^¬ check valve with the common derivative.

This structure describes the so-called parallel operation of two fluid pump assemblies. In this operation, either both fluid pump assemblies can be used simultaneously or only one each fluid ^¬ idpumpenanordnung, z. B. in alternating sequence or as redun ^¬ dantes system operated. The check valves verhin ^¬ countries that a fluid pump assembly pumps fluid into the Fluidablei ^¬ processing of the other fluid pump assembly and a volume of fluid ^¬ current in an unwanted direction.

According to a further embodiment of the invention, the second fluid pump arrangement comprises a second pump device with a second pump unit and a second pump motor, wherein the second pump motor is coupled to the second pump unit so that the second pump motor can drive the second pump unit ^¬ . The energy source is running, the power the second pump motor. The control unit is configured to read in a target value for a to be supplied from the second Pum ^¬ pen device fluid pressure and to determine a corresponding current value for the second pump motor at a predetermined pump motor speed to the target value for the information to supply fluid pressure and to control the power source so that these are the determined Current to the second Pumpenmo ^¬ tor outputs.

It should be noted that the first fluid pump arrangement can basically be coupled to a second fluid pump arrangement, which has a pressure sensor in the second fluid discharge. In this embodiment, the second fluid pump arrangement is, however, similar in structure to the first fluid pump assembly and has no pressure sensor in the flui ^¬ dableitung on. In this regard, the embodiments, the first fluid pump assembly; analogous also for the second fluid pump arrangement apply Subject Author ^¬ fend.

The second fluid pump assembly and the first Fluidpumpenanord ^¬ voltage can be supplied in common by the same power source with energy and controlled by the same control unit. Al ternatively ^¬ but both fluid pump assemblies may each egg ^¬ gene energy sources and control units.

According to a further embodiment, the Fluidpumpen- system further comprises a storage unit which is configured to store a current-speed characteristic of the first Pumpenmo ^¬ tors, wherein the current-speed characteristic speaks a supplied from the first pump unit fluid pressure ent.

In other words, a value pair which gives on the current-speed characteristic leads to a fluid pressure caused by this characteristic. The storage unit can be running be durable for read access to save the characteristic values, or so that the characteristics can be adjusted if the pump device takes Variegated ^¬ te operating characteristics over time. The storage unit may be configured to receive a characteristic of a configuration ^¬ unit, which writes the characteristics in the spoke clean ^¬ ness. These data can be transmitted ^¬ tungslos between the configuration unit and the memory unit ^¬ wired or lei.

According to a further embodiment of the invention, the memory unit is designed to store a plurality of current-speed characteristics of the first pump motor, where ^¬ corresponds to each one of the current-speed characteristics each one supplied by the first pump unit fluid pressure.

When the characteristic is an isobaric curve (pressure-constant display form or pressure lines) which the current intensity (usually expressed in Ampere) on the pump engine speed (usually expressed in revolutions per minute) applies and a particular Flu ^¬ iddruck in a graph, in the fluid discharge corresponds. The characteristic ver ^¬ running it so that the particular fluid pressure in the Fluidab ^¬ line can be set at various constellations of the current and the speed, ie, there is a river ^¬ iddruck not a specific point in the chart, but several pairs of points ( Curve) .

The reading of the current from a characteristic makes it possible that the current must not be determined algorithmically in a complex computation. The current is determined by accessing a stored characteristic, in particular ^¬ special read from a map. It can held several characteristic curves for a variety of different ^¬ union fluid pressures in the fluid discharge ^¬ to. Depending on the desired or predetermined fluid pressure in the fluid discharge pipe is never accessed the corresponding ^¬ Kennli to determine the required current intensity for the Pumpenmo ^¬ tor.

According to a further embodiment of the invention the control unit to determine the pump motor speed of the first pump motor and thus to control the source that this, adjusts the current intensity with which the first pump motor will be ^¬ driven in accordance with the characteristic curve is carried out so that the desired value for the is set or maintained by the first pump device supplied fluid pressure.

In an adaptation of the current intensity üblicherwei ^¬ se, the pump motor speed varies, so that change in the sequence and the fluid pressure and the volume flow of the fluid in the Fluidablei ^¬ processing. This may require a monitoring of the pump motor rotation ^¬ number, to make a corresponding re-adaptation of the current intensity, so that a current intensity / speed pair of values is selected on a characteristic curve, which is on the isobaric curve corresponding to the predetermined fluid pressure or target pressure.

In other words, a current from the characteristic curves when a new nominal pressure for the Flu ^¬ iddruck is set, starting from the current Pumpenmo ^¬ tordrehzahl read out, which causes the current pump motor speed to the desired fluid pressure. Since that may require a change in a changed pump motor ^¬ speed that can make a ^¬ in consequence of the altered current, for the achievement of the target pressure current ^¬ strength (again), the fluid pressure approaches in this embodiment, the target pressure iteratively, so in several consecutive steps. In each one ser steps may require an adaptation of the current intensity in Depending ^¬ ness of the characteristics and the desired fluid pressure until the desired pressure is reached. The fluid system as described herein may be in others

Words summarized as follows. The fluid system allows egg ^¬ nen operation of a multi-pump system in an embodiment without pressure sensors in the fluid discharge. In each path or to each ^¬ the fluid pump assembly, the delivery volume and the fluid iddruck in the fluid discharge can be easily adjusted without having to determine the fluid pressure with a complex pressure detection unit. The delivery volume and the speed of the individual fluid pump arrangements can be adapted to the respective Ar ^¬ beitsbedingungen.

The fluid pressure in two fluid discharges is substantially the same, so that both the fluid pumping arrangements comprise a delivery or contribute to the volume flow of the common in men ^¬ dissipation. In particular, a maximum permissible differential pressure between the first fluid discharge and the two ^¬ th fluid discharge may correspond to an opening pressure of one or both rear ^¬ check valves. For this reason, the information about the fluid pressure in both fluid discharges may be required.

In a fluid pump system as described herein ver ^¬ different modes are possible. In a parallel operation, the fluid pump assemblies are simultaneously and during GESAM ^¬ th operating time of the fluid pump system in operation. In a downstream operating mode, one pump can always be in operation (continuous operation) and a second pump is switched on at peak load (peak load operation). The downstream operation may also be modified, and a pump takes over the drive Dau ^¬ heritage of the other pump. In a cascade operation, the first pump at a fluid pressure of 5 bar and the second Pump can be operated at a fluid pressure of 4.5 bar. If the fluid pressure in the fluid discharge drops below 4.5 bar (eg due to large quantities), the second pump will help to achieve the required volume flow.

Dispensing with pressure sensors reduces the cost of such a fluid pump system. An uneven flow and delivery volume distribution to the Fluidpumpenanordnun ^¬ conditions can be detected and compensated. A separate pressure control system is provided for each Pumpenanord planning and the special ^¬ both fluid pump assemblies behave indepen ^¬ gig each other. Decisive is the fluid pressure in the common fluid discharge, which is to be regulated here. In the case of the transfer operation, it is possible to recognize from when a fluid pump arrangement actually and effectively contributes to the Fördervo ^¬ lumen. The control unit as described herein assists in maintaining fluid pressure in the common fluid drain.

According to a further aspect, a method for driving ei ^¬ nes fluid pump system is specified as described herein. The method comprises the following steps: presetting a desired value for a fluid pressure in the first fluid discharge; Determining a current value which is associated with a pump motor speed of the first pump motor and the predetermined setpoint value for the fluid pressure corresponds; and outputting the extended ^¬ read current to the first motor of the first pump fluid ^¬ pump assembly.

That the current intensity of a pump speed is associated with and corresponds to a target value for the fluid pressure means in ^¬ play that a pair of values of current and Pumpenmo ^¬ tordrehzahl lead to the predetermined fluid pressure in the Fluidablei ^¬ tung, so this cause by the current strength and the pump motor speed. The method is particularly suitable for the operation of a sensor-less pressure-control system, that for a Fluidpumpenanord ^¬ voltage without pressure sensor in the fluid discharge. The procedure ER- it enables to control a fluid pump assembly such that ei ^¬ ne pump unit is performed to achieve a desired fluid pressure under different working conditions. Thus, a recourse to a variable-speed pump device is not necessary, so that a cost for its production and control gel deleted or is reduced by the method described here re ^¬ . The method is based on the finding that there is a causal relationship between the current intensity, the rotational speed and the fluid pressure. A fluid pressure by resorting set to isobaric pressure distribution characteristics ^¬ over sole Rege ^¬ development of the current strength of the pump motor. The regulation of the current intensity can be done either by a va riable ^¬ power source or the determination or Mes ^¬ solution of the current of the pump motor and adjusting the current and speed to the desired conditions, that is at the desired fluid pressure.

The current is determined based on the currently applied Pum ^¬ pendrehzahl and the desired fluid pressure. The current can be determined via current speed at a given fluid pressure immediacy ^¬ bar using an isobaric curve. There is an isobaric curve for each ge ^¬ desired fluid pressure, and for each to-adjusting pump speed ^¬ there is an appropriate current for the current controller, that is supplied to the pump motor current. In particular, which he ^¬ imaging engine speed can not be decisive during operation of the fluid pump assembly. Decisive for the control is solely the current, which is set via a control unit. In an alternative embodiment, the flow of Pum ^¬ penmotors can also be used alone to achieve a fluid pressure in the fluid discharge. The current and voltage of the pump motor, both known, are used to determine the power transferred to the pump motor, e.g. For example, 20 watts. By means of an estimate can be determined based on the Abnahmevo ^¬ volume of fluid in the fluid discharge the pressure in the fluid ^¬ dissipation. In this case, the efficiency of the pump motor can be taken into account.

According to one embodiment of the invention, the determination of the current strength, which is associated with the pump motor speed of the first Pum ^¬ penmotors, the following step: reading the current from a characteristic curve which corresponds to the predetermined desired value for the fluid pressure.

According to a further embodiment of the invention the method further comprises the steps of: monitoring the pump motor speed of the first pump motor and adjusting the current according to the characteristic curve, so that the target value for the fluid pressure in the first fluid discharge set or keep beibe ^¬.

According to another embodiment, the method comprises wei ^¬ terhin the steps of: determining at each of a pump motor speed-current characteristic for a plurality of target values of the fluid pressure in the fluid discharge and providing the characteristics so determined to that of a pump motor speed supplied ^¬ arranged amperage read a predetermined setpoint of Flu ^¬ iddrucks.

These steps is an initial Ermit ^¬ stuffs the dependencies and correlations between the Flu ^¬ iddruck, the current strength of the pump motor and the speed of the pump motor. It can be used for any desired fluid pressure (e.g. 2 bar, 3 bar, 4 bar, 5 bar, 6 bar) is a characteristic which is applied as a current of the pump motor to the rotational speed of the pump motor ^¬ be determined. The characteristics can maintained in intervals of 1 bar or more or less than a determined and bar for later use ^¬ to. A lower and upper limit for the setpoint values of the fluid pressure is based on the intake of the fluid, that is, on the needs of an internal combustion engine which is supplied with fuel by the fluid pump arrangement.

According to another aspect of the invention, there is provided a vehicle having a fluid pumping system as described herein, wherein the fluid pumping system is configured as a fuel pumping arrangement.

In the fuel container, it is in particular egg ^¬ NEN fuel tank, wherein a fluid such. As gasoline or ^{diesel ¬} contains.

The vehicle is, for example, be a force ^¬ vehicle, such as car, bus or truck, or even a rail vehicle, a ship, an aircraft, such as Heli ^¬ copter or plane. Such a vehicle is in particular ^¬ special in that it has an internal combustion engine, which is used as a drive unit and is operated with a fluid.

According to one embodiment of the invention, the fluid pump ^¬ system is coupled to a fuel tank and is out ^¬ leads to deliver a fuel contained in the fuel tank to a drive unit of the vehicle.

According to one embodiment of the invention, the control unit is designed to carry out the method as described above. ^Exemplary embodiments of the invention will be described below with reference to the figures.

Fig. 1 shows a schematic representation of a Fluidpum- pensystems according to an embodiment of OF INVENTION ^¬ dung.

2 shows a schematic representation of a fluid pump arrangement of a fluid pump system according to one exemplary embodiment of the invention.

Fig. 3 shows a schematic representation of a vehicle according to another embodiment of the OF INVENTION ^¬ dung.

Fig. 4 shows a schematic representation of a characteristic ^¬ field of a fluid pump system according to another embodiment of the invention. Fig. 5 shows a schematic representation of the steps ei ^¬ nes method according to another Ausführungsbei ^¬ play of the invention.

The illustrations in the figures are schematic and not to scale. Like reference numerals are used, be ^¬ to drag them to the same or similar elements.

1 shows a fluid pump system 10 with a first fluid pump arrangement 100 and a second fluid pump arrangement 200. The first fluid pump arrangement 100 is coupled to a first fluid feed line 114 and via a first fluid discharge line 116 and a first check valve 11 with the common Ablei ^¬ tion 16 connected. The second fluid pump arrangement 200 is coupled to a second fluid supply line 214 and via a second fluid drain 216 and a second check valve 12 with the common derivative 16 connected. The two fluid supply lines 114, 214 are referred to in this embodiment as Zuleitungsan ^¬ order 14. Fig. 1 shows the two fluid pump assemblies 100, 200 in egg ^¬ nem parallel operation. In this exemplary mode of operation, the fluid pump assemblies may be particular that both fluid pump assemblies provide the same volume flow un ^¬ ter the same fluid pressure in the fluid discharges 116, 216th

Fig. 2 shows an example of a fluid pump assembly 100 with egg ^¬ ner pump device 105, a power source 130, a STEU ^¬ ereinheit 140 and a storage unit 150. It should be back dismissed that this construction principle for both Fluidpum ^¬ penanordnungen 100, 200 as shown in Fig. 1 may be shown. This is also indicated by the fact that some elements in FIG. 2 are each provided with two reference numerals and corresponding to the first fluid pump arrangement (100, lxx) or the second fluid pump arrangement (200, 2xx). The energy ^¬ source 130, the control unit 140 and the memory unit 150, for each fluid pump assembly 100 are provided one at 200, but these may also be unique before ^¬ hands and the control of the first and second Pumpenvor- direction 105, assume 205th The following describes the elements with reference to the first fluid pump arrangement. It should be understood that these explanations apply analogously to the second fluid pump arrangement. The pump device 105 has a pump unit 110 and egg ^¬ nen pump motor 120. The pump unit 110 and the pump motor ^¬ can be arranged in a common housing or represent a mounting unit. In any case, the pump motor 120 is designed as a DC motor and thus connected to the pump inlet. standardized coupled 110 so that the pump motor driving the pump unit at ^¬ to pump fuel through the pump unit.

It should be noted that the fluid pump arrangement 100 is described with reference to the figures in the application example of a fuel pump arrangement ^¬ . This description is for illustrative purposes only and is not intended to limit the scope of the claims to the use of the fluid pump arrangement ^¬ as a fuel pump assembly. The principles of operation set forth in the figures and the associated description are valid for any type of fluid pumps. In the following, the terms of the Fluidpumpenan ^¬ Regulation are related to a fuel pump assembly. The pump unit 110 is indirectly via a fuel supply line 114 or directly to a fuel tank (not shown) and indirectly via the fuel discharge 116 or directly with a combustion engine (not shown) verbun ^¬. Alternatively, the pump device 105 may also be arranged in the fuel tank.

The power source 130 supplies a current of predeterminable current to the pump motor 120. The rotational speed of the Pumpenmo ^¬ gate varies with the current and a change in rotational speed of the pump motor changes the pumping characteristic of the

Pumping unit so that a volume flow of the fuel from the fuel supply line 114 to the fuel discharge line 116 and also the fuel pressure in the fuel delivery 116 changed ^¬ changed. Thus, depending on the current intensity of the pump motor 120, the fuel pressure in the fuel discharge 116 can be varied.

The control unit 140 is coupled to both the power source 130 and to the pump device 105, in particular the Pumpenmo ^¬ gate 120 so that the control unit 140 of the Power source 130 supplied current set and the speed of the pump motor 120 can be determined or obtained.

The control unit 140 is further coupled to the memory unit 150 to the data stored in the storage unit 150 read out from ^¬ stored characteristic lines, respectively, and therefrom to take the current strength to be adjusted for a desired fuel pressure to ent ^¬ or determined. Fig. 3 shows a vehicle 1 having an internal combustion engine as at ^¬ drive unit 5, a fuel tank 3 and a Fluidpum- pen system 10 such as in Fig. 1. The fluid pump system 100 is arranged so that fuel is pumped via the supply line arrangement 14 and the common discharge line 16 from the fuel tank 3 to the drive unit 5.

4 shows a characteristic field in which three characteristic curves 112A, 112B, 112C are plotted as isobaric characteristic curves. The characteristic curves are entered in a diagram, which plots the current intensity 124 of the pump motor 120 over the rotational speed 122 of the pump motor 120. Each characteristic curve 112A, 112B, 112C ent ^¬ speaks in each case a fuel pressure in the fuel ^¬ derivative 116. It should be noted that the characteristic ^¬ gradients in Fig. 4 are plotted linear for purposes of illustration, this, however, depending on the respective Fluidpumpena- UTHORISATION may also have a different course.

The characteristic curve 112A, for example, 112B, a fuel pressure of 4 bar and the characteristic 112C a fuel pressure of 2 bar entspre ^¬ chen a fuel pressure of 6 bar, the characteristic curve.

Operates the fuel pump at a current speed of 123 and a pressure of 4 bar (that is, at a current as indicated by the characteristic 112B), and a change in fuel pressure occurs Set 2 bar (this corresponds to the characteristic 112C), the current according to the characteristic of 112C at the current speed 123 of the characteristic curve field is ent ^¬ accepted and is output from the power source to the pump motor as a new current 125th Changes due to the changed current and the aktu ^¬ elle pump motor speed 123, the changed current value is also read from the characteristic 112C according to the changed pump motor speed, since this characteristic corresponds to the new pre ^{¬ given} fuel pressure. Thus, an iterative arrival approximation can be achieved at the operating point for the predetermined fuel pressure ^¬.

The speed of the pump motor may be 2500-8000 To ^¬ revolutions per minute. The pump current can be between 4 amps and 17 amps.

5 shows a schematic representation of the steps of a method according to an exemplary embodiment of the invention. In a step Sl, the specification of a desired value for a fuel pressure in a fuel discharge takes place. In a following step S2, the determination of a current 125, which is associated with a pump motor speed 123 and the predetermined setpoint for the force material pressure corresponds (ie that a pair of values of amperage and pump motor ^{speed ¬} number are on an isobaric characteristic of the predetermined fuel pressure ^¬ ). In a following step S3, the the read current Substituted ^¬ ben 125 follows a DC pump motor 120 of the fluid pump assembly 100. In a step S4, the monitoring of the pump motor speed 123, and in egg ^¬ nem step S5 is followed by adjusting the current intensity 125 according to the characteristic ^¬ line, so that the setpoint for the fuel pressure in the fuel delivery 116 is set or maintained. The steps Sl to S3 can reconnect to the steps S4 and S5, so that the fuel pressure is approximately its desired value iteratively in dependence of the appropriate geän ^¬ derten current and the pump motor speed changes.

Claims

A fluid pump system (10), comprising:

a first fluid pump assembly (100) which is executed, take aufzu ^¬ a fluid via a first fluid supply line (114) and dispense a first fluid outlet (116); a second fluid pump assembly (200), which is carried out, a fluid via a second fluid supply line (214) to increase ^¬ and via a second fluid outlet (216) from ^¬ admit;

wherein the first fluid pump assembly (100) comprises:

a first pump device (105) having a first Pum ^¬ peneinheit (110) and a first pump motor (120), the first pump motor with the first pump unit (110) coupled is that the first pump motor can drive the first pump unit;

a power source (130) for powering the first pump motor (120); and

a control unit (140);

wherein the control unit (140) is configured to read a target ^¬ value to be delivered for one of the first pump device (105) fluid pressure and passed at a pre ^¬ pump motor speed to the target value for the to lie ^¬ fernden fluid pressure corresponding amperage for the ers ^¬ th To determine pump motor (120) and the energy source (130) to control so that it outputs the determined Stromstär ^¬ ke to the first pump motor (120).

Fluid pump system (10) according to claim 1,

wherein the first fluid discharge (116) and the second fluid ^{discharge ¬} (216) are coupled so that they open in a ge ^¬ common drain (16);

wherein the first fluid pump assembly (100) is coupled to the common drain (16) via a first check valve (11); wherein the second fluid pump assembly (200) is coupled via a two tes check valve (12) to the common discharge (16).

Fluid pump system (10) according to claim 1 or 2,

wherein the second fluid pump assembly (200) comprises:

a second pumping device (205) having a second pumping unit (210) and a second pumping motor (220), where ^¬ in the second pumping motor is coupled to the second pumping unit (210) so that the second pumping motor can drive the second pumping unit;

wherein the power source (130) is configured to power the second pump motor (220); and

wherein the control unit (140) is configured to read a target ^¬ value to be delivered for one of the second pump device (205) fluid pressure and passed at a pre-pump motor speed to the target value for the to lie ^¬ fernden fluid pressure corresponding amperage for the two-th pump motor ( 220) and to control the energy source (130) so that it outputs the determined Stromstär ke to the second pump motor (220).

Fluid pump system (10) according to one of the preceding ^¬ claims, further comprising a memory unit comprising (150), wherein the storage unit (150) is executed, a current-speed characteristic (112A) of the first Pumpenmo tors store (120), wherein the current strength -Travel characteristic corresponds to one of the first pump unit (110) gelie ^¬ ferten fluid pressure.

Fluid pump system (10) according to claim 4, wherein the SpeI ^¬ chereinheit (150) is executed, a plurality of current ^¬ strength-speed characteristic lines (112A, 112B, 112C) of the store the first pump motor (120), each of the power each strength-speed characteristics corresponds to one of the first pump unit (110) delivered fluid pressure.

Fluid pump system (10) according to any one of claims 4 or 5, wherein the control unit (140) is designed to a ^¬ the pump motor speed (123) of the first pump motor (120) to ^¬ mediate;

wherein the control unit (140) is designed to control the energy source (130) so that it adjusts the current at which the first pump motor (120) is operated according to the characteristic, so that the setpoint for the supplied from the first pump device Fluid pressure is turned on or maintained.

Method for activating a fluid pump system (10) according to one of Claims 1 to 6, comprising the following steps:

Predetermining (S1) a desired value for a fluid pressure in the first fluid discharge (116);

Determining (S2) a current intensity (125) which (120) is penmotordrehzahl a pump (123) of the first pump motor supplied ^¬ arranged and corresponds to the predetermined target value for the pressure fluid ^¬;

Outputting (S3) the readout current (125) to the first pump motor (120) of the first fluid pump arrangement (100).

The method of claim 7, wherein determining the current ^intensity (125) associated with the pump motor speed (123) of the first pump motor (120) comprises the step:

Reading out the current (125) from a characteristic curve (112C) which speaks ent ^¬ the predetermined desired value for the fluid pressure. The method of claim 8, further comprising

Steps :

Monitoring (S4) the pump motor speed (123) of the first pump motor (120);

Adjusting (S5) the current (125) according to the characteristic (112C) so that the setpoint for the fluid pressure in the first fluid discharge (116) is adjusted or maintained. 10. The method according to any one of claims 7 to 9, further ^{comprising ¬} the steps:

Determining in each case a pump motor speed-current characteristic (112A, 112B, 112C) for a plurality of nominal values ^¬ value of the fluid pressure in the fluid discharge;

Providing the thus determined characteristics to the one

Pump motor speed (123) associated current (125) at a given setpoint of the fluid pressure out ^¬ sen. 11. vehicle (1) with a fluid pump system (10) according to any one of claims 1 to 6, wherein the fluid pump system (10) is designed as a fuel pump assembly.

The vehicle of claim 11, wherein the fluid pump system (10) is coupled to a fuel tank (3) and configured to supply a fuel contained in the fuel tank to a drive unit (5) of the vehicle. 13. Vehicle (1) according to claim 11 or 12, wherein the control ^¬ unit (140) is designed to carry out the method according to one of claims 7 to 10.