Methods for operating pumps and fluid supply systems having such pumps

Abstract

This invention relates to a method for operating a pump, particularly a fluid supply system, having a pump chamber and an actively controllable inlet valve and an actively controllable outlet valve for the pump chamber, wherein the pressure (p) of the fluid to be delivered is adjusted by the pump based on an adjustment parameter (V) for fluid delivery, and wherein at least one of the inlet valve (211) and outlet valve (212) is operated only within a complete cycle (Z) of the pump (200) when fluid should be delivered, and at least one of the inlet valve and outlet valve is not operated when fluid should not be delivered. Furthermore, this invention relates to a fluid supply system.

Description

Technical Field

[0001] The present invention relates to a method for operating a pump, a computing unit for implementing the method, a computer program, and a fluid supply system having such a pump and such a computing unit. Background Technology

[0002] In the aftertreatment of exhaust gases from motor vehicles, the so-called SCR (Selective Catalytic Reduction) method is used, especially for the reduction of nitrogen oxides (NOx). Here, an aqueous urea solution (HWL) is introduced as a reducing agent into the typically oxygen-rich exhaust gases.

[0003] For this purpose, a metering module or metering valve can be used, which includes a nozzle for injecting or adding an aqueous urea solution into the exhaust gas stream. Upstream of the SCR catalyst, the aqueous urea solution reacts to form ammonia, which then combines with nitrogen oxides at the SCR catalyst, thereby producing water and nitrogen.

[0004] The metering valve is typically connected to the delivery unit via a pressure line. A pump or delivery pump in the delivery unit pumps the urea solution from the reducing agent tank to the metering valve or metering module. Typically, an additional loop is connected to the reducing agent tank, through which excess urea solution can be returned. A throttling plate or valve in the loop controls the backflow. Summary of the Invention

[0005] According to the present invention, a method for operating a pump, a computing unit, a fluid supply system, and a computer program for implementing the method are proposed. Advantageous design options include: using, under controlled conditions, the control timing, control angle, opening timing, opening angle, control duration, control angle range, opening duration, and opening angle range of the inlet valve as control parameters for the inlet valve, each parameter being set to a predetermined value; wherein, under controlled conditions, the control timing, control angle, opening timing, opening angle, control duration, control angle range, opening duration, and opening angle range of the outlet valve are used as control parameters for the outlet valve, each parameter being set to a predetermined value; wherein the pump frequency is adjusted to a predetermined minimum possible value greater than zero; wherein the pressure of the fluid to be delivered is adjusted by means of PI or PID control, at least within a portion of the available mass flow rate range; wherein the value depends on the pump frequency.

[0006] This invention relates to a method for operating a pump having a pump chamber with actively controllable, i.e., selectively openable and closable, inlet and outlet valves. Although the invention is described particularly with respect to fluid supply systems, the proposed method can also be used in other pumps, provided that at least the inlet and outlet valves are actively controllable, in which the pump is used in a delivery unit or as a delivery unit within the fluid supply system.

[0007] "Actively controllable valves" (this applies not only to inlet valves but also to outlet valves) refers to valves that can be actively and purposefully opened and closed, for example, by means of a magnetic switch or by means of an electromagnet. Correspondingly, other valves, or those conventionally used in pumps within SCR systems, are of this type, opening passively or automatically when a specific pressure is applied. Thus, with such conventional valves, fluid can be drawn into the pump chamber through the inlet valve during the pump's suction phase. Then, during the pumping or delivery phase, the fluid is expelled from the pump chamber through the outlet valve when the inlet valve is closed.

[0008] In the proposed method, in order to transport a fluid, such as an aqueous solution of urea, that is, if the fluid should be transported, the pressure of the fluid to be transported, to be provided by the pump, is adjusted to the target value based on the adjustment parameters.

[0009] Especially since the valve can be actively controlled, one feasible approach to this pressure regulation is to use the control parameters of the inlet or outlet valve, or the pump frequency of the pump, as regulation parameters. It is also possible to consider using multiple regulation parameters simultaneously.

[0010] The control parameters for the inlet and outlet valves include, for example, the start time of valve actuation (i.e., the start of actuation or energization), the start time of valve opening, the duration of valve actuation (i.e., the duration of actuation or energization), the duration of valve opening, the start time of valve actuation, the start time of valve opening, the duration of valve actuation, and the duration of valve opening. It should be noted that the valve actuation and opening times are usually slightly offset from each other, because, for example, a certain current must first be generated in the magnet until the valve opens. In this regard, one of these two times is usually chosen as the control parameter. This also applies to the end and closing times of actuation, or the resulting duration of actuation and the duration of opening. Similarly, the control parameters for the inlet and outlet valves can be described based on angles (i.e., between 0° and 360°, relative to the shaft of the pump or drive unit, or, if necessary, relative to a complete cycle of a linear drive unit). That is, for example, the valve actuation angle or a range of actuation angles can be used as control parameters.

[0011] In a conventional piston pump, the delivery element corresponds to a piston. For example, a so-called diaphragm pump can also be used for fluid supply systems, in which the pump chamber is closed on one side by a flexible diaphragm that serves as the delivery element. The diaphragm can reciprocate by means of an electromagnetic linear actuator as a drive device or by means of an electrically driven rotary drive device with an eccentric wheel, in order to reduce or increase the volume of the pump chamber.

[0012] The pump frequency, which can also be used as a parameter for adjustment, can then correspond to, for example, the frequency at which the electromagnetic linear actuator, as a driving device (in the case of a diaphragm pump or a similar pump with a linear actuator), moves. In the case of a conventional piston pump, or a diaphragm pump with a rotary drive, the pump frequency can also correspond to the rotational speed (of a motor or electric motor) (the piston moves after the motor or electric motor has converted the rotary motion into linear motion).

[0013] By using these special adjustment parameters, especially through the use of actively controllable valves, it is possible to achieve different operating points for the pump, which was not possible until now. For example, it is possible to achieve an operating point with no fluid volumetric flow rate (or zero fluid volumetric flow rate) at a specific delivery pressure (such as 9 bar between the outlet and inlet), and more precisely, this is done without using additional hardware (such as a circuit into the tank).

[0014] Furthermore, a key feature is that the delivery direction can be reversed via a corresponding valve. This allows for the interchange of the functions of the inlet and outlet valves, possible through active control. If the liquid-filled system is susceptible to damage due to freezing and the resulting ice pressure, it is advantageous that the delivery direction can be reversed without additional hardware, such as a directional valve, to empty the system after the end of the operating cycle.

[0015] It is also possible that either the pump frequency is adjusted to a constant value and one or more of the valve's control parameters are used as adjustment parameters, or these control parameters of the valve are adjusted to constant values ​​and the pump frequency is used as adjustment parameters.

[0016] Despite the particular advantages of the actively controllable valves, such as the principled efficient operation of the pump, a certain degree of inefficiency is accompanied by the low mass flow rate of the fluid to be transported. This is especially true because all the valves are opened and closed during one pump cycle, as is the case with a pump having passive valves. However, the timing or duration can be adjusted using the actively controllable valves.

[0017] Another aspect is that the pump drive cannot be operated at arbitrarily low frequencies or speeds due to friction; that is, the pump frequency can either be brought to zero by shutting off the drive or, however, can only be brought to a specific minimum value, such as 500 U / min. However, for this minimum value, the mass flow rate of the fluid does not reach zero when the valve is normally operated.

[0018] Within the scope of this invention, it is now proposed that, within a complete cycle of the pump—that is, within a complete stroke of the pump's delivery element including lifting and lowering—starting from a specific position and returning to that specific position (e.g., a complete rotation of the rotary drive), at least one of the valves, namely at least one of the inlet and outlet valves, is operated only when needed, but not always. The valve, or at least one of the valves, can therefore remain in its current position, i.e., open or closed. Specifically, at least one of the actively controllable valves is operated only when fluid should be delivered, and not operated when fluid should not be delivered. This avoids unnecessary valve operation, improving energy efficiency and extending the valve's lifespan, and thus the pump's lifespan. The pump is always able to operate with optimal fill levels, corresponding to so-called volumetric pump operation.

[0019] Ideally, zero delivery or zero flow should be achieved using the pump when fluid should not be delivered. Similarly, the pump drive can be left unoperated, thereby extending its lifespan. Furthermore, the inlet valve can be kept open, i.e., energized, during periods when fluid should not be delivered, to allow the fluid to be pumped back into the inlet during the delivery phase. However, the drive itself can also remain operational to generate zero delivery, for example, when the valve is closed. Additionally, both valves can be operated to generate zero delivery (e.g., to achieve minimal filling, even if this means poor hydraulic efficiency).

[0020] A feasible solution for regulating pressure and controlling the valve only when needed is two-point regulation. Here, the control of the inlet and outlet valves is used as regulation parameters, meaning that switching between an on state where the valve is controlled and an off state where the valve is not controlled is possible. According to two-point regulation, two thresholds can be used for this purpose: an upper threshold slightly larger than the target pressure value to be adjusted and a lower threshold slightly smaller than the target pressure value to be adjusted. The specific interval between the thresholds and the target values ​​can be appropriately selected. If the actual pressure value reaches the upper threshold, the control of the valve is interrupted; if the actual value reaches the lower threshold, the control is (re)started. The pump frequency is adjusted to a predetermined, and particularly minimally possible, positive-zero value.

[0021] This two-point adjustment is used at least within a portion of the available mass flow rate range, where "available mass flow rate range" refers to the range between the minimum and maximum possible mass flow rates that can be produced by the pump. The two-point adjustment can effectively produce particularly small mass flow rates, as it is preferably used at least for small mass flow rates; however, it can also be used for the entire available mass flow rate range.

[0022] Another feasible approach for regulating pressure and operating the valves only when necessary is to adjust the frequency of the control cycles of the inlet and outlet valves as a control parameter. This frequency of repetition is limited upwards by the pump frequency, because for the pump's intended operation, each valve should or can open and close only once for each complete stroke of the delivery element from a particular position until the next arrival at that particular position. A pump frequency of 500 U / min thus allows, for example, a maximum of eight control cycles or a repetition frequency of 8 Hz. However, this repetition frequency can vary below this maximum value and thus can be used particularly well as a control parameter. Therefore, for example, it is not necessary to operate the valves in every complete cycle of the pump. In an example with a pump frequency of 500 U / min or a maximum repetition frequency of 8 Hz, for example, a repetition frequency of 4 Hz, the valves are generally operated only in the second complete stroke.

[0023] As a control method, PI(D) control is particularly considered here, which involves using a proportional share of the amplification factor, an integral share, and, if necessary, a differential share, and the corresponding time constant. This can effectively produce very small mass flow rates, and therefore this control method is preferred for at least small mass flow rates, although it can also be used for the full range of available mass flow rates.

[0024] Another feasible method for pressure regulation is to use the pump frequency as a regulation parameter, wherein the inlet and outlet valves are controlled. This can effectively generate particularly high mass flow rates because it achieves particularly smooth and dynamic regulation. Therefore, this regulation method is preferably used for at least high mass flow rates, although it can also be used for the full range of available mass flow rates.

[0025] These aforementioned adjustment methods can now be advantageously combined for different mass flow rate ranges. Therefore, it is preferable to use the two-point adjustment or the adjustment using repetition frequency as the adjustment parameter for the first mass flow rate range and the adjustment using pump frequency as the adjustment parameter for the second mass flow rate range, wherein the second mass flow rate range at least partially includes a mass flow rate higher than the first mass flow rate range. Suitablely, the two mass flow rate ranges together cover the available mass flow rate range and are separated from each other by specific limit values. To avoid potentially continuous back-and-forth switching between the two adjustment methods at the limit values, two different limit values ​​or hysteresis can also be used depending on which side the mass flow rate approaches from. That is, when the mass flow rate increases, it is possible to switch to another adjustment method with a higher limit value than when the mass flow rate decreases.

[0026] The control parameters mentioned at the beginning of the valve can be set to predetermined values, particularly dependent on the pump frequency, within the range of adjustment used. These values ​​can thus be optimized in terms of pump efficiency, as will be explained below with reference to the accompanying drawings.

[0027] The computing unit according to the invention, such as a motor vehicle controller, a motor controller, or an exhaust aftertreatment controller, is particularly configured in terms of programming technology to implement the method according to the invention.

[0028] Furthermore, a fluid supply system, particularly an SCR system, is the subject of this invention, which includes a pump and a computing unit according to the invention, said pump having a pump chamber and an actively controllable inlet valve and / or an actively controllable outlet valve for the pump chamber.

[0029] It is also advantageous to implement the method according to the invention in the form of a computer program or computer program product having program code for implementing all method steps, because this results in particularly low costs, especially if the controller used for execution is also used for other tasks and therefore already exists. Suitable data carriers for providing the computer program are, in particular, magnetic storage, optical storage, and electrical storage, such as hard disks, flash memory, EEPROM, DVDs, etc. The program can also be downloaded via computer networks (Internet, intranet, etc.).

[0030] Further advantages and design solutions of the present invention will become apparent from the specification and drawings. Attached Figure Description

[0031] The present invention is schematically illustrated in the accompanying drawings with reference to embodiments, and will be described below with reference to the drawings. Wherein: Figure 1 A preferred embodiment of the fluid supply system according to the invention is illustrated schematically; Figure 2 The schematic diagram illustrates the possible control process for the active valve in the pump; Figures 3 to 6 The flowcharts of the method according to the invention in different preferred embodiments are shown, along with explanations thereof. Detailed Implementation

[0032] exist Figure 1 The diagram schematically and exemplaryly illustrates a preferred embodiment of the fluid supply system 100 according to the invention. The fluid supply system 100 is specifically configured as an SCR system and includes a delivery unit 110 having a pump or delivery pump 200 configured to deliver a reducing agent 121 (or a reducing agent solution) as a fluid to be delivered from a reducing agent tank 120 through a pressure line 122 to a metering module or metering valve 130, which will be described in detail below. There, the reducing agent 121 is then injected into the exhaust system 170 of the internal combustion engine.

[0033] Furthermore, a pressure sensor 140 (which can also be installed in the delivery module) is provided to measure the pressure in at least the pressure line 122. A computing unit 150, configured as an exhaust gas aftertreatment controller, is connected to the pressure sensor 140 and obtains information about the pressure in the pressure line 122 from the pressure sensor. Additionally, the exhaust gas aftertreatment controller 150 is connected to the delivery module 110, and therein particularly to the pump 111 and the metering module 130, for the purpose of controlling the metering module.

[0034] Furthermore, the fluid supply system 100 exemplary includes a loop 160 through which the reducing agent can be returned from the system (see Q). RL The fluid is directed to the reducing agent reservoir 120. An exemplary throttling plate or valve 161 is arranged in this loop 160, which provides localized flow resistance. However, it should be noted that this loop can also be eliminated in the proposed method with actively controlled valves.

[0035] The exhaust gas aftertreatment control device is configured to coordinate the actuators of the system based on significant data, such as data received by the motor controller or by sensors for temperature, pressure, and nitrogen oxide content in the exhaust gas, to add an aqueous urea solution to the exhaust system before the SCR according to the operating strategy.

[0036] In addition, on-board diagnostics (OBD) functions monitor components and parts of the exhaust aftertreatment system that are important for complying with exhaust emission limits.

[0037] The pump 200 has a pump chamber 210, which is internally connected to corresponding pipelines via an inlet valve 211 and an outlet valve 212. Both the inlet valve 211 and the outlet valve 212 can be actively controlled or manipulated, meaning they can be opened or closed as needed. For this purpose, the exhaust gas aftertreatment device 150 can be used (or, if necessary, other suitable computing units can be used, which can also be considered integrated into the pump's electronics, particularly the electronics of the motor or valves).

[0038] Furthermore, the pump 200 has a delivery element 220 with a drive mechanism for expanding and reducing the volume of the pump chamber 210. It should be noted that the specific type of the delivery element 220, such as a piston or similar component, is not important to the proposed method.

[0039] exist Figure 2 The diagram illustrates, for example, in Figure 1 The diagram illustrates the possible control flow of the active valve in a pump used in a fluid supply system. A curve B showing the change in the location or position of the pump's delivery element over time t is provided, where the location or position evolves between the top dead center OT and the bottom dead center UT, and also represents the change in volume (the curve between the largest and smallest volumes).

[0040] In addition, the control signal S for the inlet valve is shown with respect to time t. E and the control signal S used for the outlet valve A Here we can see that after the bottom dead center (UT), that is, when the volume of the pump chamber rises again, the inlet valve is operated to allow fluid to be drawn in. Correspondingly, after the top dead center (OT), that is, when the volume of the pump chamber falls again, the outlet valve is operated to allow fluid to be discharged.

[0041] Here, the valve is operated at specific times for opening: the inlet valve is operated at time t1, and the outlet valve is operated at time t2. Furthermore, it can be seen that times t1 and t2 are separated from the previous dead point by a time interval a or c. In this sense, the operation times t1 and t2 can also be defined as the duration of the delay relative to the corresponding dead point.

[0042] The duration of the control signal is represented by b or d. In this way, the four control parameters a, b, c, and d of the valve (or t1 and t2 instead of a and c) can be used for pump operation, and these four control parameters can be adjusted to specific values, as will be explained in more detail below.

[0043] It should be noted that the actual opening duration of the valve may sometimes deviate from the corresponding duration of the control signal due to the necessary actuator movement, but this can be taken into account when designing the controller accordingly.

[0044] Furthermore, the pump frequency of the pump is shown, which, within the scope of the invention, can also be used as a regulating parameter for pressure regulation in certain embodiments. This is depicted by the period duration of the variation curve B, which corresponds to the reciprocal of the pump frequency f. The period duration, in turn, corresponds to the complete cycle Z of the pump as mentioned at the beginning.

[0045] exist Figures 3 to 6 The flowcharts of the method according to the invention in different preferred embodiments are shown, along with explanations thereof. Figure 3 The diagram schematically, without specific scales, first shows, for example, the pump frequency f, which corresponds to the rotational speed, and the fluid mass flow rate or mass flow rate of the fluid to be transported. .

[0046] In the mass flow rate As can be seen, the mass flow rate increases linearly (to the right) continuously from zero (left), which should clearly indicate that, in principle, the mass flow rate can be arbitrarily changed from zero all the way to a certain maximum value with this pump, and this is also expected in normal operation.

[0047] At the pump frequency f, it can be seen that the pump frequency will not drop to a specific minimum value f. min Below this point, the reason, as mentioned at the beginning, is particularly that the necessary frictional force of the drive unit cannot be overcome below a minimum value, such as 500 U / min or approximately 8 Hz. Similarly, the torque acting on the drive unit by the pump pressure may be problematic here. This leaves a mass flow rate range B1, achieved by using a constant pump frequency, such as f... min To change the mass flow rate from zero to a specific value. Within the mass flow rate range B2 covering the remaining area, the mass flow rate can be changed, for example, by means of the pump frequency (as an adjustment parameter).

[0048] Therefore, in a preferred embodiment of the method according to the invention, two-point adjustment is used within the mass flow range B1 to adjust the pressure of the fluid to be delivered.

[0049] exist Figure 4 The pressure p is shown for this time t, where the target value p for the pressure is shown. soll and the upper threshold p O and lower threshold p U Furthermore, the value of the corresponding adjustment parameter V for this two-point adjustment is also shown with respect to time t. This adjustment parameter can occupy two values: 1 for turning on (i.e., controlling the valve) and 0 for turning off (i.e., not controlling the valve).

[0050] The pressure p is initially zero, meaning the adjustment parameter is set to 1 to control the valve. Specifically, each valve is opened and closed once per complete stroke of the delivery element. Only when the upper threshold p is reached... O Only when the pressure reaches the lower threshold p is the adjustment parameter set to 0, meaning the operation is interrupted and thus the complete stroke of the delivery element exists without the control valve. U Then the valve is controlled again, that is, the adjustment parameter is set to 1.

[0051] This two-point adjustment, as mentioned, is particularly useful within the mass flow range B1. If a mass flow rate within the mass flow range B2 is desired, the two-point adjustment can be used to adjust the pump frequency as a regulating parameter, especially PI(D) adjustment, for pressure regulation.

[0052] During the adjustment within the mass flow range B2, but also, for example, during two-point adjustment within the mass flow range B1, the control parameters of the valve (e.g., as referenced) are... Figure 2 The parameters a, b, c, d, as explained, are preferably adjusted to the optimal values ​​possible, which depend on the current pump frequency.

[0053] exist Figure 5 The diagram illustrates the mass flow rate in terms of pump frequency f, expressed in U / min, for example, as a regulating parameter. The two curves here, from left to right, represent the valve's constant but different control parameters a, b, c, and d. Here, the mass flow rate can be clearly seen. It can also vary very drastically with the pump frequency f, but it is also clear that there is a set of control parameters for which the mass flow rate is particularly high, that is, for which particularly efficient operation is possible. For this purpose, AP is used to illustrate four sets of control parameters, each for a specific pump frequency f, which can achieve optimal operation at their respective pump frequencies and should therefore be used as much as possible.

[0054] exist Figure 6 The mass flow rate is schematically plotted with respect to time t. and repetition frequency f W The repetition frequency f W This indicates how frequently the valve performs a complete opening and closing cycle per unit of time. It can be clearly seen from these two variation curves that the repetition frequency f... W Changes can also alter the mass flow rate. .

[0055] In another preferred embodiment of the method according to the invention, the following adjustment is therefore used within the mass flow rate range B1, for which the repetition frequency f is adjusted. W Used as a regulating parameter to adjust the pressure of the fluid to be transported.

[0056] This regulation is particularly PI(D) regulation, which, as mentioned, is especially used within the mass flow range B1. Within the mass flow range B2, the previously mentioned regulation using the pump frequency as a control parameter can be used. In this embodiment, the control parameters explained above can also be used for the valve.

Claims

1. A method for using a pump (200) for operating a delivery unit (110) of a fluid supply system (100), the pump having a pump chamber (210) and an actively controllable inlet valve (211) and an actively controllable outlet valve (212) for the pump chamber (210). Among them, adjusting parameters (V, f, f) W Based on the pressure (p) of the fluid (121) to be transported, which is to be provided by the pump (200), the pressure (p) is adjusted for transporting the fluid (121), and At least one of the inlet valve (211) and outlet valve (212) is operated only during a complete cycle (Z) of the pump (200) when fluid should be delivered, and at least one of the inlet valve and outlet valve is not operated when fluid should not be delivered. Its features are, The pressure (p) of the fluid to be transported (121) is regulated by means of two-point regulation within at least a portion of the available mass flow rate range, wherein the use (V) of the control of the inlet valve (211) and the outlet valve (212) is used as regulation parameters, and wherein the pump frequency (f) is adjusted to a predetermined value (f min ), The pressure (p) of the fluid to be transported (121) is regulated by means of adjustment, at least within a portion of the available mass flow rate range, wherein the pump frequency (f) is used as the regulation parameter, and wherein the inlet valve (211) and the outlet valve (212) are operated. The two-point adjustment is used for the first mass flow range (B1) and the adjustment of the pump frequency (f) as an adjustment parameter is used for the second mass flow range (B2), wherein the second mass flow range (B2) includes at least a portion of the mass flow rate that is higher than that of the first mass flow range (B1).

2. A method for using a pump (200) for operating a delivery unit (110) of a fluid supply system (100), the pump having a pump chamber (210) and an actively controllable inlet valve (211) and an actively controllable outlet valve (212) for the pump chamber (210). Among them, adjusting parameters (V, f, f) W Based on the pressure (p) of the fluid (121) to be transported, which is to be provided by the pump (200), the pressure (p) is adjusted for transporting the fluid (121), and At least one of the inlet valve (211) and outlet valve (212) is operated only during a complete cycle (Z) of the pump (200) when fluid should be delivered, and at least one of the inlet valve and outlet valve is not operated when fluid should not be delivered. Its features are, The pressure (p) of the fluid to be delivered (121) is regulated by means of regulation, at least within a portion of the available mass flow rate range, wherein the repetition frequency (f) of the control cycle of the inlet valve (211) and the outlet valve (212) is used as a regulation parameter. W ), The pressure (p) of the fluid to be transported (121) is regulated by means of adjustment, at least within a portion of the available mass flow rate range, wherein the pump frequency (f) is used as the regulation parameter, and wherein the inlet valve (211) and the outlet valve (212) are operated. The repetition frequency (f) of the control cycle of the inlet valve (211) and outlet valve (212) will be used as a control parameter. W The adjustment of the pump frequency (f) is used for the first mass flow range (B1) and the adjustment of the pump frequency (f) as an adjustment parameter is used for the second mass flow range (B2), wherein the second mass flow range (B2) includes at least a portion of the mass flow rate that is higher than that of the first mass flow range (B1).

3. The method according to claim 1 or 2, wherein, When fluid should not be delivered, zero delivery is made by means of the pump, and / or the drive of the pump (200) is not operated, and / or the inlet valve (211) remains open.

4. The method according to claim 1, wherein, under controlled conditions, the control parameter (A) of the inlet valve is... P The control time (t1), control angle, opening time, opening angle, control duration (b), control angle range, opening duration, and opening angle range of the inlet valve are all set to predetermined values.

5. The method according to claim 1, wherein, under controlled conditions, the control parameter (A) of the outlet valve is... P The control time (t2) of the outlet valve, the control angle of the outlet valve, the opening time of the outlet valve, the opening angle of the outlet valve, the control duration (d) of the outlet valve, the control angle range of the outlet valve, the opening duration of the outlet valve, and the opening angle range of the outlet valve are all set to predetermined values.

6. The method of claim 1, wherein the pump frequency (f) is adjusted to a predetermined minimum possible value greater than zero (f0). min ).

7. The method according to claim 1 or 2, wherein the pressure (p) of the fluid to be delivered (121) is adjusted by means of PI or PID regulation at least within a portion of the available mass flow rate range.

8. The method according to claim 4 or 5, wherein the value depends on the pump frequency (f).

9. A calculation unit (150) configured to implement all method steps of the method according to any one of the preceding claims.

10. A fluid supply system (100) having a pump (200) and a computing unit (150) according to claim 9, the pump having a pump chamber (210) and an actively controllable inlet valve (211) and an actively controllable outlet valve (212) for the pump chamber.

11. A computer program product having a computer program that, when executed on a computing unit (150), causes the computing unit (150) to perform all the method steps of the method according to any one of claims 1 to 8.

12. A machine-readable storage medium having a computer program stored thereon, which, when executed on a computing unit (150), causes the computing unit (150) to perform all the method steps of the method according to any one of claims 1 to 8.

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