Delivery device for delivering a medium and for limiting a system pressure

Abstract

A delivery device for delivering a medium in a vehicle and for limiting a system pressure of the delivery device includes a vehicle pump, which is driven by an electric motor. The electric motor is controlled by a controller, the controller being configured to detect an actual rotational speed of the electric motor and an actual operating current of the electric motor. If the actual operating current of the electric motor exceeds a predefined operating current limit value, the controller is configured to generate a first signal relating to a system pressure being exceeded. The predefined operating current limit value is dependent on the actual rotational speed of the electric motor.

Claims

1-10. (canceled)

11. A delivery device for delivering a medium in a vehicle and for limiting a system pressure of the delivery device, the delivery device comprising: a vehicle pump; an electric motor configured to drive the vehicle pump: and a controller configured to control the electric motor, wherein: the controller is configured to ascertain a present rotational speed of the electric motor and a present operating current of the electric motor, the controller is configured to generate a first signal relating to a system pressure exceedance of the delivery device if the present operating current of the electric motor exceeds a predefined operating current threshold value, and the predefined operating current threshold value is dependent on the present rotational speed of the electric motor.

12. The delivery device as claimed in claim 11, wherein the controller is configured to, on the basis of a functional relationship between the system pressure of the delivery device, the operating current of the electric motor and the rotational speed of the electric motor, calculate a present system pressure of the delivery device as a function of the present rotational speed and the present operating current of the electric motor, and wherein the controller is configured to generate the first signal relating to the system pressure exceedance of the delivery device if the calculated present system pressure of the delivery device exceeds a predefined operating pressure threshold value.

13. The delivery device as claimed in claim 11, wherein in the controller there is stored a pump-specific profile of the operating current as a function of the rotational speed at a given pressure.

14. The delivery device as claimed in claim 11, wherein the controller is configured to limit or reduce the present operating current of the electric motor and/or the present rotational speed of the electric motor if the controller generates the first signal relating to the system pressure exceedance of the delivery device.

15. The delivery device as claimed in claim 12, wherein the controller is configured to generate a second signal relating to a critical system pressure exceedance of the delivery device if the calculated present system pressure of the delivery device exceeds a predefined critical system pressure threshold value; and wherein the controller is configured to deactivate the delivery device if the controller generates the second signal relating to the critical system pressure exceedance of the delivery device and the system pressure of the delivery device exceeds the critical system pressure threshold value during a predefined time period.

16. A vehicle (300) having a delivery device (100) as claimed in claim 11, wherein the vehicle pump is a fuel pump configured to deliver fuel for an internal combustion engine of the vehicle.

17. A method for delivering a medium and for limiting a system pressure of a delivery device having a vehicle pump driven by an electric motor, the method comprising: monitoring a present rotational speed and a present operating current of the electric motor, and generating a first signal relating to a system pressure exceedance of the delivery device if the present operating current of the electric motor exceeds a predefined operating current threshold value (S2), wherein the predefined operating current threshold value is dependent on the present rotational speed of the electric motor.

18. The method as claimed in claim 17, the method further comprising: calculating a present system pressure of the delivery device as a function of the present rotational speed and the present operating current of the electric motor on the basis of a functional relationship between the system pressure of the delivery device, the operating current of the electric motor and the rotational speed of the electric motor; and generating the first signal relating to the system pressure exceedance of the delivery device if the calculated present system pressure of the vehicle pump exceeds a predefined system pressure threshold value.

19. A non-transitory computer-readable medium storing a program which, when executed on a processor, commands the processor to carry out the method as claimed in claim 17.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 shows a delivery device according to an exemplary embodiment of the invention;

[0037] FIG. 2 shows a diagram according to an exemplary embodiment of the invention;

[0038] FIG. 3 shows a vehicle according to an exemplary embodiment of the invention; and

[0039] FIG. 4 shows a flow diagram of a method according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0040] The figures are illustrated schematically and not to scale.

[0041] FIG. 1 shows a delivery device 100 for delivering a medium in a vehicle and for limiting a system pressure of the delivery device. The delivery device has a vehicle pump 101, an electric motor 102 for driving the vehicle pump 101, and a controller 103 for controlling the electric motor 102, which electric motor comprises a stator 110 and a rotor 111. The controller 103 is configured to determine a present rotational speed of the electric motor 102 and a present operating current of the electric motor 102. Furthermore, the controller is configured to generate a first signal relating to a system pressure exceedance of the delivery device 100 if the present operating current of the electric motor 102 exceeds a predefined operating current threshold value, wherein the predefined operating current threshold value is dependent on the present rotational speed of the electric motor 102. In this exemplary embodiment, the vehicle pump 101 is a gerotor pump or a toothed-ring pump. Here, the driving toothed gear 104 runs eccentrically in the internal toothing 105 of the vehicle pump 101. The toothed gear 104 is driven by the electric motor 102. As a result of the rotation of the toothed gear 104, the medium is conveyed between the tooth spaces, whereby the medium is transported from an inlet 106 of the pump 101 to an outlet 107 of the pump 101 in the arrow direction 108. Here, the gerotor pump is merely an example and should not be regarded as restrictive. The invention may be realized for numerous different pump types.

[0042] In a further exemplary embodiment illustrated on the basis of FIG. 1, the controller 103 is configured to carry out a method for limiting the system pressure of the vehicle pump 101. Here, the method includes ascertaining the rotational speed of the vehicle pump 101. Here, if the electric motor 102 of the vehicle pump 101 is an electrically commutated electric motor, the rotational speed may be a known value, because electrically commutated electric motors are typically regulated in terms of rotational speed. In the case of mechanically commutated electric motors, it is possible for separate ascertainment of the rotational speed to be performed on the basis of current ripples, because, in hitherto existing systems, there is typically no need for rotational speed regulation to be implemented. Furthermore, the method comprises ascertaining the phase current of the electric motor 102. Furthermore, according to the method, a value that represents the rotational speed of the vehicle pump 101 and a value that represents the phase current of the vehicle pump 101 are fed to an evaluation unit. The evaluation unit may, for example, be a part of the controller 103. Furthermore, the evaluation unit may also be a further component of the delivery device 100, which, for the sake of clarity, is not illustrated in FIG. 1. The method furthermore comprises ascertaining, in the evaluation unit, the present pressure generated by the fuel pump 101. Furthermore, in the method, the present pressure is compared with a first pressure threshold value, and a signal is generated in the event of an exceedance of the first pressure threshold value. The first pressure threshold value may correspond to the operating pressure threshold value.

[0043] Furthermore, the controller 103 may be configured to implement further measures upon the generation of the signal in the event of exceedance of the first pressure threshold value. Here, in typical normal operation, the controller may regulate the system pressure to a certain preset value by virtue of the present operating current of the electric motor 102 being regulated to a rotational-speed-dependent current value stored in a characteristic map. Here, a pressure setpoint value, which it is sought to attain through regulation of the operating current, may be communicated to the controller 103 from a superordinate controller of the internal combustion engine. Furthermore, the controller may have a typical behavior pattern in the event of fault operation. For example, such a behavior pattern may be invoked if fuel is no longer being extracted and, in the presence of very small extraction quantities, the demanded first pressure threshold value can no longer be adhered to, for example because a minimum rotational speed cannot be undershot. If necessary, the controller 103 may attempt to limit the system pressure of the vehicle pump 101 to a certain value below the first pressure threshold value by limiting the current to a rotational -speed-dependent value corresponding to a characteristic map. Furthermore, it is also possible for the rotational speed of the electric motor 102 or a combination of rotational speed and operating current to be limited. In the event of an exceedance of a second pressure threshold value, the controller can generate a second signal. The second pressure threshold value may, for example, correspond to the critical system pressure threshold value. The controller may attempt to reduce the system pressure of the vehicle pump 101 to a certain value below the second pressure threshold value by limiting the current to a rotational -speed-dependent value corresponding to a characteristic map, or by limiting the rotational speed, or by a combination of both measures. Furthermore, the controller may also be configured to directly shut down the delivery device 100 and/or the pump 101 if it has not been possible for a certain length of time to limit the second pressure threshold value. This serves for system protection, in order that, for example, relatively severe damage can be prevented. Furthermore, the controller may also be configured to generate a warning message, which is transmitted for example to the engine controller, to the effect that the pump has been deactivated. The engine controller can then implement corresponding measures. If necessary, the controller 103 can trigger a restart of the delivery device 100, in the case of which, furthermore, an active control signal with the information “pump active” or with a valid pressure or rotational speed preset value is defined.

[0044] Furthermore, FIG. 1 illustrates a non-transitory computer-readable medium 109 on which, for example, a program for carry out the method, which is carried out by the controller 103, is stored. Furthermore, a functional relationship between operating current of the electric motor 102, rotational speed of the electric motor 102 and system pressure of the vehicle pump 101 may also be stored on the computer-readable medium.

[0045] FIG. 2 illustrates a diagram according to an exemplary embodiment of the invention. The diagram comprises a first axis 201, which represents the rotational speed of the electric motor, and a second axis 202, which represents the operating current or the energy consumption of the electric motor 102. The first axis 201 may alternatively also denote the pump voltage. It may, for example, be the case that, in mechanically commutated electric motors, direct determination of the rotational speed is not possible. Here, the units in FIG. 2 are not specified. For example, the unit of the axis 201 is revolutions per minute, and the unit of the axis 202 is amperes. Furthermore, in the diagram, various curves 205, 206, 207, 208 and 209 are illustrated, which represent the current consumption of the electric motor as a function of the rotational speed. Here, the curve 205 corresponds to a pump-specific profile of the operating current for different rotational speeds in the presence of a constant system pressure of the vehicle pump P0. The curve 206 shows the pump-specific profile of the operating current in the presence of a constant pressure P1, the curve 207 shows the profile in the presence of a constant pressure P2, the curve 208 shows the profile in the presence of a constant pressure P3, and the curve 203 shows the profile in the presence of a constant pressure P4. Here, the pressures P0 to P4 are designated in an increasing sequence, that is to say the pressure P0 is lower than the pressure P1, the pressure P1 is lower than the pressure P2, the pressure P2 is lower than the pressure P3, and the pressure P3 is lower than the pressure P4, as is also illustrated by the arrow 210. System pressure threshold value curves 203 and 204 are also illustrated in FIG. 2. Thus, in FIG. 2, it can be seen that the curves 204 and 203 are dependent on the rotational speed illustrated on the axis 201. Here, the curve 203 corresponds to the predefined system pressure threshold value, and the curve 204 corresponds to the critical system pressure threshold value.

[0046] The controller 103 is configured to ascertain the rotational speed and the operating current of the electric motor 102. If the combination of the ascertained rotational speed and the ascertained operating current yields a point that lies below the curve 203 in the diagram 200, then the system pressure threshold value is not exceeded, and if the point defined by ascertained rotational speed and ascertained operating current lies between the curves 203 and 204, then the system pressure threshold value is exceeded and the critical system pressure threshold value is undershot, such that the controller 103 generates the first signal. If the point resulting from ascertained rotational speed and ascertained operating current is arranged above the curve 204, the system pressure threshold value and the critical system pressure threshold value are exceeded, such that the second signal is also generated. The system pressure threshold values or system pressure threshold value curves 203 and 204 may be stored in the controller 103. It is furthermore also possible for only one of the system pressure threshold value curves 203 or 204 to be stored in the controller 103. Here, it is also possible for data or points that define the system pressure threshold values or system pressure threshold value curves 203 and 204 to be stored in the controller 103.

[0047] FIG. 3 illustrates a vehicle 300 according to an exemplary embodiment of the invention. The vehicle has an internal combustion, engine 301, a fuel tank 302 and a delivery device 100, which is described in the context off the present invention and which supplies fuel from the fuel tank 302 to the internal combustion engine 301. The delivery device 100 comprises a pump 101, an electric motor 102 and a controller 103. Here, the controller may, for example, be part of the engine controller or may also have been retrofitted in order to improve the reliability of the delivery device 100.

[0048] FIG. 4 illustrates a flow diagram of a method for delivering a medium and for limiting a system pressure of a delivery device that has a vehicle pump driven by an electric motor. Here, the method comprises monitoring a present rotational speed and a present operating current of the electric motor (S1), and generating a first signal relating to a system pressure exceedance of the delivery device if the present operating current of the electric motor exceeds a predefined operating current threshold value (S2). Here, the predefined operating current threshold value is dependent on the present rotational speed of the electric motor.

[0049] It is additionally pointed out that the expressions “comprising” or “having” do not exclude other elements, and the expressions “a” or “an” do not rule out a multiplicity. It is also pointed out that features that have been described with reference to one of the above exemplary embodiments or embodiments may also be used in combination with other features of other above-described exemplary embodiments or embodiments. Reference designations in the claims are not to be regarded as being restrictive.

[0050] Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.