Method for operating a centrifugal separator

Abstract

Method for operating a centrifugal separator (1) which is assigned to a prime mover and a work machine, wherein the centrifugal separator (1) has at least one rotatably mounted rotor (10) which is set in rotation at a variable speed by means of a drive (2) controlled by a control unit (3), characterized in that the prime mover is formed by an internal combustion engine and the work machine is formed by a motor vehicle and in that the speed of the rotor (10) is controlled as a function of the acoustic emissions of the prime mover and / or as a function of the acoustic emissions of the work machine, wherein the speed of the rotor (10) is controlled such that the rotor (10) is operated at such a maximum speed that the centrifugal separator (1) is not perceptible to the human ear within the respective current acoustic emissions of the prime mover or the work machine.

Description

[0001] The present invention relates to a method for operating a centrifugal separator which is associated with a prime mover and a working machine, wherein the centrifugal separator has at least one rotatably mounted rotor which is set in rotation at a variable speed by means of a drive controlled by a control unit.

[0002] Methods of the type mentioned above are known from documents EP 1 537 301 B1 and EP 1 532 353 B1. The documents describe methods for cleaning crankcase gas generated during the operation of an internal combustion engine used to power a vehicle. A centrifuge with a centrifuge rotor is used, which is attached to a vehicle for cleaning crankcase gas. An electric motor is used to rotate the centrifuge rotor, which can be connected to a power source present on the vehicle for its operation. The separation efficiency of the centrifuge is changed by changing the rotational speed of the electric motor and thus of the centrifuge rotor, while the internal combustion engine continues to operate.The rotational speed of the electric motor is changed, in particular, based on data representative of an actual change in the amount of crankcase gas produced by the internal combustion engine, or based on a detected change in a crankcase gas flow generated as a result of the production of crankcase gas by the internal combustion engine, or based on a detected change in a crankcase gas pressure generated as a result of the production of crankcase gas by the internal combustion engine. The aim of this is to drive the centrifuge rotor with the lowest possible drive energy as needed, ensuring effective cleaning of the crankcase ventilation gas without expending unnecessary, excessive drive energy.

[0003] Modern centrifugal separators are often operated at high speeds of several tens of thousands of revolutions per minute. While this results in good cleaning efficiency, it is always associated with significant acoustic emissions, particularly at high frequencies that are unpleasant to the human ear, leading to disturbances and discomfort for people nearby. These acoustic emissions are caused in particular by rotor imbalances, the rotor bearings, and the rotor drive. The acoustic emissions of the centrifugal separator are particularly disruptive when other accompanying acoustic emissions, which temporarily mask the centrifugal separator noise, disappear, and the centrifugal separator can be heard for a long time due to the rotor's relatively long coasting and running down due to its high initial speed. In addition, the rotor's rotational energy is lost unused during coasting and running down.

[0004] WO 2016 / 008755 A1 discloses a method for operating a centrifuge with a rotating drum, wherein the rotational speed of the drum is controlled such that the noise generated by the centrifuge does not exceed a noise level limit. Furthermore, surrounding machines such as mills and pumps, which also generate noise, can be taken into account in the control system.

[0005] EP 2 465 613 A1 discloses a hydraulic drive of a centrifuge.

[0006] US 2006 / 0 048 761 A1 discloses the operation of a centrifuge with a rotor, wherein the centrifuge is associated with an internal combustion engine in a vehicle.

[0007] US 5 919 123 A discloses an electric drive for a centrifuge.

[0008] US 5 146 505 A discloses a control of a drive of a centrifuge.

[0009] The object of the present invention is therefore to create a method of the type mentioned above that avoids or at least significantly reduces disturbances and stresses on people in the vicinity of centrifugal separators on a power machine and / or work machine. Furthermore, the method should make it possible to utilize the rotor's rotational energy during its run-down and coast-down phases.

[0010] According to the invention, the problem is solved by a method having the features of patent claim 1.

[0011] According to the invention, the essential criteria according to which the speed of the rotor of the centrifugal separator is controlled are the acoustic emissions of the prime mover and the working machine to which the centrifugal separator is assigned, which ensures that the centrifugal separator operates in an acoustically inconspicuous manner in the noise environment of the prime mover and the working machine and does not cause any acoustic disturbance to people in the vicinity of the centrifugal separator.

[0012] According to the invention, the method according to the invention is used on a power machine formed by an internal combustion engine, since a particularly great benefit can be achieved here because it is often the case that people are or have to be in the vicinity of a centrifugal separator assigned to this internal combustion engine during operation of the internal combustion engine.

[0013] At the same time, the method is applied to a work machine formed by a motor vehicle. This also offers significant benefits because, during operation of the motor vehicle, its driver and, if applicable, passengers must always be in the vicinity of a centrifugal separator associated with the motor vehicle and its internal combustion engine, which is usually present within the vehicle.

[0014] Furthermore, the method according to the invention provides for the rotor speed to be controlled in such a way that the rotor operates at a maximum speed such that the centrifugal separator is imperceptible to the human ear within the current acoustic emissions of the prime mover or the working machine. This makes the centrifugal separator acoustically inaudible to people in its vicinity, thus eliminating interference, stress, or even annoyance.

[0015] Advantageously, signals representative of the acoustic emissions of the prime mover or driven machine, which are to be fed to the control unit, are determined from at least one operational parameter already stored or recorded on the prime mover or driven machine for another purpose. This has the advantage that no separate sensor system is required to record the current acoustic emissions.

[0016] A related development provides that the operating parameter from which the signals to be fed to the control unit are determined is the current engine operating point in a stored engine operating map. Since modern engines, such as internal combustion engines, are typically operated using electronic data from a stored engine operating map, this map data, which generally also exhibits a certain correlation to the engine's acoustic emissions, can be used to obtain or generate control data for driving the rotor of the centrifugal separator.

[0017] In a further specific embodiment of the method, it is proposed that the at least one detected operational parameter from which the signals to be supplied to the control unit are determined is a rotational speed measured value and / or a load value of the engine.

[0018] Alternatively or additionally, it is possible that the recorded operating parameters from which the signals to be supplied to the control unit are determined are a working machine movement speed and / or an engaged gear of a working machine transmission.

[0019] Another alternative or additional possibility is that the operational parameters from which the signals to be fed to the control unit are determined are stored, speed-dependent wind and / or rolling noises of the working machine.

[0020] For the method according to the invention, it is further proposed that the parameters from which the signals to be supplied to the control unit are determined are generated from an on-board and / or bus network of the prime mover or driven machine and supplied to the control unit. The control unit, formed by an electronics unit integrated into the centrifugal separator, assumes control of the speed of the centrifugal separator's rotor in accordance with characteristic values ​​stored in the control unit for the control signals. This advantageously utilizes an on-board or bus network present in many prime movers or driven machines, keeping the hardware and software requirements for the control unit low.

[0021] According to another embodiment of the method according to the invention, it is possible for signals representative of the acoustic emissions of the engine or the working machine to be fed to the control unit to be recorded using one or more acoustic sensors. This allows the actual acoustic emissions to be recorded directly within the method, and the method can be carried out independently of data that is already available or recorded for other purposes.

[0022] If necessary, a microphone present in or on the prime mover or work machine, such as a telephone device, can be used as the acoustic sensor or as one of the several acoustic sensors.

[0023] Furthermore, an electric drive is preferably used to drive the rotor, which is switched by the control unit, in accordance with the signals supplied to it, between a rotor-driving mode and a rotor-braking mode, as well as a switched-off state. The electric drive can be used to influence the rotor's speed in any desired manner.

[0024] The process offers the advantageous possibility of generating electrical energy using the electric drive in its rotor-braking mode and feeding it back into the electrical network of the prime mover or driven machine. This contributes to particularly high energy efficiency in the operation of the centrifugal separator.

[0025] In an alternative embodiment of the method, a hydraulic drive is used to drive the rotor, which is switched by the control unit at least between a driving operating mode and a switch-off state in accordance with the signals supplied to it.

[0026] In addition, it can be provided that the hydraulic drive can be switched into a braking mode by the control unit in accordance with the signals supplied to it when there is a need to reduce the speed of the rotor.

[0027] Alternatively, and regardless of the type of rotor drive, the control unit can activate a separate braking device associated with the rotor when a reduction in the rotor speed is required. The braking device can then be, for example, a mechanical braking device that uses friction to reduce the rotor speed when necessary.

[0028] In order to enable the fastest possible response and lowest possible delay within the process, it is proposed that, in accordance with signals supplied to the control unit by a machine control unit of the prime mover or driven machine prior to an impending stop of the prime mover or driven machine, the control unit brings the rotor to a standstill before or until the prime mover or driven machine stops. This ensures that the acoustic emissions of the centrifugal separator remain unobtrusive and non-disturbing to people in the vicinity, even during demanding operational moments.

[0029] An additional useful application of the method according to the invention in connection with an internal combustion engine is that, in accordance with signals supplied to the control unit by a control unit of the internal combustion engine prior to an impending start of the internal combustion engine, the control unit activates the drive of the rotor for a pre-evacuation of the crankcase of the internal combustion engine before the start of the internal combustion engine. This advantageously reduces the energy requirement of a starter motor that starts the internal combustion engine. The use of the method specified here is also technically useful in connection with active crankcase ventilation systems with electrically, hydraulically, or pneumatically driven fans or compressors or controlled suction jet nozzles.

[0030] The method according to the invention effectively protects people, such as persons in motor vehicles, from annoying noises from centrifugal separators, but at the same time the function of the centrifugal separator is not noticeably impaired, since it can be operated in phases of higher ambient noise even in operating modes with stronger acoustic emissions without this being perceived by the people in the surrounding area or perceived as disturbing.

[0031] Finally, a particularly useful application of the method according to the invention is seen in its use for operating a centrifugal separator that deoils crankcase ventilation gas or cleans lubricating oil on an internal combustion engine of a hybrid vehicle or a motor vehicle with an automatic engine start / stop system. Such vehicles frequently experience phases in which their internal combustion engine is idle and then does not generate any acoustic emissions. Therefore, a conventionally operated centrifugal separator would be particularly disruptive in this case, but this is reliably avoided with the method according to the invention.

[0032] Overall, the method according to the invention and its configurations achieve improved, non-disturbing acoustic behavior of the centrifugal separator, improved durability with a longer service life, and reduced energy consumption for driving the centrifugal separator's rotor. This enables rapid rotor start-up, and, thanks to the control of the rotor speed, critical speed ranges, particularly in the range of the rotor's natural frequencies, can be quickly traversed. This allows for greater imbalances in the rotor, which can be designed, for example, in the form of a disc separator, and higher maximum rotor speeds.

[0033] In the following, an embodiment of the invention is explained with reference to a drawing.

[0034] The only figure ( Fig. 1) of the drawing shows in a purely schematic representation a centrifugal separator with a rotor with drive and with a control unit controlling the drive according to several control parameters.

[0035] The Fig. The lower part of Figure 1 schematically shows a centrifugal separator 1 having a rotor 10, which is designed, for example, as a stack-and-disk separator. The rotor 10 is rotatably mounted in a separator housing (not specifically shown here) by means of a rotor shaft 11 and two rotor bearings 13. By means of a drive 2 connected to the rotor shaft 11, such as an electric motor, the rotor 10 can be set in rotation during operation of the centrifugal separator 1 in order to separate droplets or particles of a second medium from a first medium flowing through the rotor 10 by means of centrifugal force, as is known per se.

[0036] Furthermore, the embodiment of the centrifugal separator 1 shown here comprises a brake 12, which can exert a braking force on the rotor shaft 11 and thus also on the rotor 10 by means of friction, if necessary.

[0037] Alternatively, the brake 12 can also be an electric brake, possibly with energy recovery.

[0038] The centrifugal separator 1 is assigned to a prime mover not further shown in the drawing and to a working machine, for example an internal combustion engine of a motor vehicle, and can specifically serve, for example, to deoil crankcase ventilation gas of the internal combustion engine.

[0039] An electronic control unit 3 is assigned to the centrifugal separator 1. This control unit controls the drive 2 of the rotor 10 of the centrifugal separator 1 at a variable speed via electrical signal and supply connections 20, in accordance with parameters to be explained below. Via the electrical signal connection 20, the control unit 3 detects the current actual speed of the drive 2 and thus of the rotor 10 and compares it with the current, parameter-dependently calculated target speed in order to increase or decrease the actual speed accordingly in the event of deviations. If a reduction in the speed of the rotor 10 is required, the control unit 3 activates the brake 12 via a further electrical signal connection 30.

[0040] A first parameter used in the embodiment shown in the drawing to control the speed of the drive 2 of the rotor 10 is the speed of an associated internal combustion engine. This speed is determined via a Fig. 1 indicated internal combustion engine speed sensor 4 and transmitted as a measurement signal to the control unit 3 via a further electrical signal connection 40.

[0041] A further source for one or more additional control parameters supplied to control unit 3 is an engine control unit 5 of the associated internal combustion engine. Modern internal combustion engines already have engine control units that record or store various operating parameters of the internal combustion engine and can additionally be used to control drive 2. Suitable data or signals are transmitted from engine control unit 5 to control unit 3 via signal connection 50.

[0042] Another parameter used to control the drive 2 is the speed of an associated vehicle, such as a motor vehicle with an internal combustion engine. The speed of the vehicle is determined by a vehicle speed sensor 6 and fed to the control unit 3 as a measurement signal via a further signal connection 60.

[0043] Finally, in the exemplary embodiment, an acoustic sensor 7 is provided which detects noises or a noise level in the environment of the centrifugal separator 1, for example in an interior of a motor vehicle with an internal combustion engine equipped with the centrifugal separator 1, and feeds it to the control unit 3 as a measurement signal via a further signal connection 70.

[0044] By means of the control unit 3, the rotational speed of the rotor 10 is controlled depending on the signals supplied to the control unit 3, which are representative of the acoustic emissions of the prime mover and / or the driven machine. In particular, the rotational speed of the rotor 10 is controlled such that the rotor 10 is operated at a maximum speed such that the centrifugal separator 1 is not perceptible to the human ear, or at least not disturbing, within the respective current acoustic emissions of the associated prime mover and / or driven machine.

[0045] By means of the drive 2 controlled by the control unit 3, the rotor 10 can be rapidly accelerated and brought to a current desired speed, which depends on the parameters processed in the control unit 3. Conversely, the rotor 10 can be quickly decelerated, if necessary, and brought to a lower speed or to a standstill using the brake 12 provided here, which is also controlled by the control unit 3.

[0046] In practice, it may also be sufficient to carry out the method if the control unit 3 receives fewer different signals than in Fig. 1. Conversely, it is also possible to use even more signals than shown in the drawing for controlling the drive 2 of the rotor 10 by means of the control unit 3. List of reference symbols: 1 centrifugal separator 10 Rotor 11 Rotor shaft 12 Brake 13 rotor bearings 2 drives for 10 20 Signal and / or supply connection between 2 and 3 3 Control unit 30 signal connection from 3 to 12 4 Engine speed sensor 40 Signal connection from 4 to 3 5 Engine control unit of the internal combustion engine 50 Signal connection from 5 to 3 6 Vehicle speed sensor 60 signal connection from 6 to 3 7 acoustic sensor 70 Signal connection from 7 to 3

Claims

[1] Method for operating a centrifugal separator (1) which is assigned to a prime mover and a working machine, wherein the centrifugal separator (1) has at least one rotatably mounted rotor (10) which is set in rotation at a variable speed by means of a drive (2) controlled by a control unit (3), characterized by that the prime mover is formed by an internal combustion engine and the work machine is formed by a motor vehicle and that the speed of the rotor (10) is controlled as a function of the acoustic emissions of the prime mover and / or as a function of the acoustic emissions of the work machine, wherein the speed of the rotor (10) is controlled in such a way that the rotor (10) is operated at such a maximum speed that the centrifugal separator (1) is not perceptible to the human ear within the respective current acoustic emissions of the prime mover or the work machine. [2] Method according to claim 1, characterized by that signals representative of the acoustic emissions of the prime mover or the working machine, to be supplied to the control unit (3), are determined from at least one operational parameter which is already stored or recorded on the prime mover or the working machine for another purpose. [3] Method according to claim 2, characterized by that the operating parameter from which the signals to be supplied to the control unit (3) are determined is the current engine operating point in a stored engine operating map. [4] Method according to claim 2 or 3, characterized by that the at least one detected operating parameter from which the signals to be supplied to the control unit (3) are determined is a rotational speed measured value and / or a load value of the engine. [5] Method according to claim 2 or 3, characterized bythat the recorded operating parameters from which the signals to be supplied to the control unit (3) are determined are a working machine movement speed and / or an engaged gear of a working machine transmission. [6] Method according to one of claims 2 to 5, characterized by that the operational parameters from which the signals to be fed to the control unit (3) are determined are stored, speed-dependent wind and / or rolling noises of the working machine. [7] Method according to one of claims 2 to 6, characterized bythat the parameters from which the signals to be fed to the control unit (3) are determined are generated from an on-board and / or bus network of the prime mover or the working machine and fed to the control unit (3), and that the control unit (3) formed by an electronic unit integrated in the centrifugal separator (1) takes over the speed control of the rotor (10) of the centrifugal separator (1) in accordance with characteristic values ​​stored in the control unit (3) for the control signals. [8] Method according to claim 1, characterized by that signals representative of the acoustic emissions of the engine or the working machine, to be fed to the control unit (3), are detected by means of one or more acoustic sensors (7). [9] Method according to claim 8, characterized bythat a microphone present in or on the engine or working machine is used as the acoustic sensor (7) or as one of the several acoustic sensors (7). [10] Method according to one of claims 1 to 9, characterized by that an electric drive is used as the drive (2) of the rotor (10), which is switched by the control unit (3) in accordance with the signals supplied to it between an operating mode driving the rotor (10) and an operating mode braking the rotor (10) and a switched-off state. [11] Method according to claim 10, characterized by that electrical energy is generated by means of the electric drive (2) in its operating mode braking the rotor (10) and fed back into an electrical network of the prime mover or the working machine. [12] Method according to one of claims 1 to 9, characterized bythat a hydraulic drive is used as the drive (2) of the rotor (10), which is switched by the control unit (3) according to the signals supplied to it at least between a driving operating mode and a switch-off state. [13] Method according to claim 12, characterized by that the hydraulic drive (2) is switched into a braking mode by the control unit (3) in accordance with the signals supplied to it when there is a need to reduce the speed of the rotor (10). [14] Method according to one of claims 1 to 12, characterized by that a separate braking device (12) associated with the rotor (10) or the rotor shaft (11) or the drive (2) is activated by the control unit (3) when there is a need to reduce the speed of the rotor (10). [15] Method according to one of claims 1 to 14, characterized byin that, in accordance with signals which are supplied to the control unit (3) by a machine control device (5) of the prime mover or the working machine before an impending stop of the prime mover or the working machine announcing this, the control unit (3) brings the rotor (10) to a standstill before or until the prime mover or the working machine stops. [16] Method according to claim 1, characterized by in that, in accordance with signals which are supplied to the control unit (3) by a control device (5) of the internal combustion engine before an impending start of the internal combustion engine, announcing this, the control unit (3) activates the drive (2) of the rotor (10) for a pre-evacuation of the crankcase of the internal combustion engine before the start of the internal combustion engine takes place. [17] Method according to claim 1, characterized bythat it is used to operate a centrifugal separator (1) which deoils crankcase ventilation gas or cleans lubricating oil on an internal combustion engine of a hybrid motor vehicle or a motor vehicle with an automatic engine start-stop system.

Images