SE541546C2

SE541546C2 - Cyclone separator with motor controlled guide blades and related devices comprising such cyclone separator

Info

Publication number: SE541546C2
Application number: SE1751117A
Authority: SE
Inventors: Jonatan Bergström
Original assignee: Scania Cv Ab
Priority date: 2017-09-14
Filing date: 2017-09-14
Publication date: 2019-10-29
Also published as: SE1751117A1; DE102018006620B4; DE102018006620A1

Abstract

Herein a cyclone separator arrangement (1) is disclosed for separating particles from a flow of fluid. The arrangement (1) comprises a housing (5) comprising an inflow opening (7) and an outflow opening (9) spaced apart along an axis (11) and at least one guide blade (13) rotationally arranged around the axis (11) between the inflow opening (7) and the outflow opening (9). The at least one guide blade (13) extends radially with respect to the axis (11) and is provided with a pitch angle (a1) to provide a cyclone around the axis (11) when fluid is flowing from the inflow opening (7) towards the outflow opening (9). The arrangement (1) further comprises a motor (15) configured to selectively rotate the at least one guide blade (13) around the axis (11). The present disclosure further relates to an air intake arrangement (25), a combustion engine (27), and a vehicle (29).

Description

Cyclone separator with motor controlled guide blades and related devices comprising such cyclone separator TECHNICAL FIELD The present invention relates to a cyclone separator for separating particles from a flow of fluid. The present invention further relates to an air intake arrangement for a combustion engine, wherein the air intake arrangement comprises a cyclone separator. Further, the present invention relates to a combustion engine and a vehicle.

BACKGROUND A cyclone separator is a device capable of separating particulates from a flow of fluid, i.e. a flow of air, gas and/or liquid, without the use of filter elements, through cyclone separation. Rotational effects and gravity are used to separate mixtures of solids and fluids. A cyclone separator can also be used to separate droplets of liquid from a gaseous stream.

Cyclone separators are for example used in air intake arrangements for combustion engines. In such applications, the cyclone separator is usually arranged to separate particles from incoming air before the air is led to a conventional air filter comprising a filter element. Such a filter element comprises a filter media through which the air is ducted. The filter media comprises a semi-permeable material through which air can pass and in which particles over a certain size are trapped. The filter media causes a flow resistance which causes a pressure drop over the filter element. The flow resistance and the pressure drop over the filter element increases when particles are trapped in the filter media. Thereby, after a certain operational time, the filter element must be replaced.

In most applications, including when arranged in an air intake arrangement of a combustion engine, it is wanted to obtain a low pressure drop over a cyclone separator. In cases where a cyclone separator is arranged in an air intake arrangement of a combustion engine, a low pressure drop is wanted since a high pressure drop in the air intake of the combustion engine may reduce the fuel efficiency and the performance of the engine. A pressure drop over a cyclone separator is partially caused by the fact that the cyclone separator works with the principle of separation through rotational effects. That is, fluid is usually flowing straight into the cyclone separator. In the cyclone separator, the straight flow is transformed into a cyclone, which causes a pressure drop over the cyclone.

Since a cyclone separator works with the principle of separation through rotational effects, the separation efficiency of the cyclone separator depends on the angular velocity of the cyclone. However, a high angular velocity of the cyclone causes a high pressure drop over the cyclone separator. Conversely, a low angular velocity of the cyclone causes a low separation efficiency of the cyclone separator.

SUMMARY It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks.

According to a first aspect of the invention, the object is achieved by a cyclone separator arrangement for separating particles from a flow of fluid. The arrangement comprises a housing comprising an inflow opening and an outflow opening spaced apart along an axis and at least one guide blade rotationally arranged around the axis between the inflow opening and the outflow opening. The at least one guide blade extends radially with respect to the axis and is provided with a pitch angle to provide a cyclone around the axis when fluid is flowing from the inflow opening towards the outflow opening. The arrangement further comprises a motor configured to selectively rotate the at least one guide blade around the axis.

Since the arrangement comprises a motor configured to selectively rotate the at least one guide blade around the axis, conditions are provided for achieving a simple and efficient adaptation of the separation efficiency and the pressure drop over the cyclone separator arrangement. That is, by controlling the motor to rotate the at least one guide blade in a first rotational direction, an angular velocity of the cyclone can be increased to increase the separation efficiency of the cyclone separator arrangement. Further, by controlling the motor to rotate the at least one guide blade in a first rotational direction with a lower rotational speed, or by controlling the motor to rotate the at least one guide blade in a second rotational direction, being opposite to the first rotational direction, the angular velocity of the cyclone can be reduced to reduce the pressure drop over the cyclone separator arrangement.

Accordingly, a cyclone separator arrangement is provided capable of providing a simple and efficient adaptation of the separation efficiency and of the pressure drop. Thereby, a more consistent separation efficiency, as well as a more consistent pressure drop, can be obtained at different flow rates of fluid flowing from the inflow opening towards the outflow opening.

Accordingly, a cyclone separator arrangement is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the abovementioned object is achieved.

The arrangement further comprises a control arrangement and a flow detecting unit, wherein the flow detecting unit is configured to detect the flow rate of fluid flowing from the inflow opening towards the outflow opening, and wherein the control arrangement is configured to control the rotational speed of the motor in dependence of the flow rate of fluid flowing from the inflow opening towards the outflow opening. Thereby, a more consistent separation efficiency, as well as a more consistent pressure drop, is obtained at different flow rates of fluid flowing from the inflow opening towards the outflow opening.

The at least one guide blade is provided with a pitch angle to provide a cyclone having a first rotational direction around the axis when fluid is flowing from the inflow opening towards the outflow opening, and wherein the control arrangement is configured to control the motor to rotate the at least one guide blade in the first rotational direction around the axis when the flow rate of fluid flowing from the inflow opening towards the outflow opening is below a first threshold value. Thereby, the angular velocity of the cyclone around the axis is increased when the flow rate of fluid flowing from the inflow opening towards the outflow opening is below the first threshold value. As a result, the separation efficiency of the cyclone separator arrangement is increased when the flow rate of fluid flowing from the inflow opening towards the outflow opening is below the first threshold value.

The control arrangement is configured to control the rotational velocity of the at least one guide blade in the first rotational direction essentially inversely proportional to the flow rate of fluid flowing from the inflow opening towards the outflow opening. Accordingly, the control arrangement will control the rotational velocity of the at least one guide blade such that the at least one guide blade rotates at a higher speed in the first rotational direction when the flow rate is low and rotates at a lower speed when the flow rate is higher. As a result, a more consistent separation efficiency, as well as a more consistent pressure drop, is obtained at different flow rates of fluid flowing from the inflow opening towards the outflow opening.

Optionally, the control arrangement is configured to control the motor to rotate the at least one guide blade in a second rotational direction around the axis, being opposite to the first rotational direction, when the flow rate of fluid flowing from the inflow opening towards the outflow opening is above a second threshold value. Thereby, the angular velocity of the cyclone around the axis is decreased when the flow rate of fluid flowing from the inflow opening towards the outflow opening is above the second threshold value. As a result, the pressure drop between the inflow opening and the outflow opening of the cyclone separator arrangement is reduced when the flow rate of fluid flowing from the inflow opening towards the outflow opening is above the second threshold value.

Optionally, the control arrangement is configured to control the rotational velocity of the at least one guide blade in the second rotational direction essentially proportional to the flow rate of fluid flowing from the inflow opening towards the outflow opening. Thus, the control arrangement will control the rotational velocity of the at least one guide blade such that the at least one guide blade rotates at a lower speed in the second rotational direction when the flow rate is lower and rotates at a higher speed in the second rotational direction when the flow rate is higher. As a result, a more consistent pressure drop, as well as a more consistent separation efficiency, is obtained at different flow rates of fluid flowing from the inflow opening towards the outflow opening.

Optionally, the arrangement comprises a centre hub coaxially arranged with respect to the axis, wherein the at least one guide blade is arranged at the centre hub and extends radially therefrom. Thereby, a simple and reliable cyclone separator arrangement is provided capable of achieving a simple and efficient adaptation of the separation efficiency and of the pressure drop.

Optionally, the motor is configured to rotate the centre hub. Thereby, a simple and reliable adaptation of the separation efficiency and of the pressure drop can be provided.

Optionally, the motor is arranged inside the centre hub. Thereby, a simple and reliable adaptation of the separation efficiency and of the pressure drop can be provided. Further, since the motor is arranged inside the centre hub, fluid flowing from the inflow opening towards the outflow opening may provide cooling of the motor.

According to second aspect of the invention, the object is achieved by an air intake arrangement for a combustion engine, wherein the air intake arrangement is configured to duct ambient air to the combustion engine, and wherein the air intake arrangement comprises a cyclone separator arrangement according to some embodiments. The flow rate of air ducted to a combustion engine varies to a great extent. That is, during idling, the flow rate is low and during high load situations, the flow rate is high. Since the air intake arrangement comprises a cyclone separator arrangement according to some embodiments, an air intake arrangement is provided capable of adapting the separation efficiency and the pressure drop in dependence of the flow rate of ambient air ducted to the engine.

Accordingly, an air intake arrangement is provided which can provide a more consistent separation efficiency and a more consistent pressure drop at different flow rates of air ducted to the combustion engine. Thus, an air intake arrangement may be provided with an improved separation efficiency at low load situations of the engine and potentially a lower pressure drop over the air intake arrangement at high load situations of the combustion engine. Further, since the air intake arrangement may be provided with an improved separation efficiency at low load situations of the engine, the dust accumulation in a filter element of the air intake arrangement can be reduced. Further, the life time of the filter element can be increased, i.e. the operational time available before the filter element must be replaced can be increased. Still further, the demands on the filter element can be reduced meaning that a low prize filter element, and/or a filter having a low pressure drop, can be used. Still further, droplets of liquids, such as water, can be separated from the air in a more efficient manner which may enhance the performance of the filter element and prolong the life time thereof.

Accordingly, an air intake arrangement is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

According to third aspect of the invention, the object is achieved by a combustion engine comprising the air intake arrangement according to some embodiments. The flow rate of air ducted to a combustion engine varies to a great extent. That is, during idling the flow rate is low and during high load situations the flow rate is high. Since the combustion engine comprises an air intake arrangement provided with a potentially lower pressure drop over the air intake arrangement at high load situations of the engine, the efficiency of the engine at high load situations can be improved. Further, since the air intake arrangement can be provided with an improved separation efficiency at low load situations of the engine, the dust accumulation in a filter element of the air intake arrangement of the engine can be reduced. Further, the life time of the filter element can be increased, i.e. the operational time available before the filter element must be replaced can be increased. Still further, the demands on the filter element can be reduced meaning that a low prize filter element, and/or a filter having a low pressure drop, can be used. Still further, droplets of liquids, such as water, can be separated from the air in a more efficient manner which may enhance the performance of the filter element and prolong the life time thereof.

Accordingly, a combustion engine is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the combustion engine comprises an engine control unit, wherein the cyclone separator arrangement of the air intake arrangement comprises a flow detecting unit, and wherein the flow detecting unit forms part of the engine control unit. Thereby, the flow rate of fluid flowing from the inflow opening towards the outflow opening can be detected in a simple and reliable manner. Further, the flow rate of fluid flowing from the inflow opening towards the outflow opening can be detected using an already existing component of the combustion engine.

According to fourth aspect of the invention, the object is achieved by a vehicle comprising a combustion engine according to some embodiments. Since the vehicle comprises a combustion engine according to some embodiments, a vehicle is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS Various aspects of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which: Fig. 1 illustrates a cyclone separator arrangement, according to some embodiments, Fig. 2 illustrates a combustion engine comprising an air intake arrangement, according to some embodiments, and Fig. 3 illustrates a vehicle comprising the combustion engine illustrated in Fig. 2.

DETAILED DESCRIPTION Aspects of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

Fig. 1 illustrates a cyclone separator arrangement 1, according to some embodiments. The cyclone separator arrangement 1 is arranged to separate particles from a flow of fluid. The cyclone separator arrangement 1 comprises a housing 5 with an inflow opening 7 and an outflow opening 9 spaced apart along an axis 11. According to the illustrated embodiments, the housing 5 is cylindrically shaped. The cyclone separator arrangement 1 comprises guide blades 13 arranged in the housing 5 between the inflow opening 7 and the outflow opening 9.

In Fig. 1, only three guide blades 13 are indicated with the reference sign “13” for the reason of brevity and clarity. The cyclone separator arrangement 1 according to the illustrated embodiments comprises eight guide blades 13, of which only six are visible. The cyclone separator arrangement 1 may comprise another number of guide blades 13 than eight, for example a number within the range of 1 - 7, or 9 - 20, or the like. Accordingly, the cyclone separator arrangement 1 may comprise one guide blade 13. However, for the reason of brevity and clarity, the guide blade 13 according to such embodiments, is below referred to as “the guide blades 13”.

The guide blades 13 are rotationally arranged around the axis 11 between the inflow opening 7 and the outflow opening 9. The guide blades 13 extend radially with respect to the axis 11 and is provided with a pitch angle a1 to provide a cyclone around the axis 11 having a first rotational direction d1 around the axis 11 when fluid is flowing from the inflow opening 7 towards the outflow opening 9. Due to the cyclone around the axis 11, particles in the fluid that are heavier than the surrounding fluid are forced towards an inner wall 12 of the housing 5 by centrifugal force. The cyclone separator arrangement 1 comprises a tube 14 coaxially arranged to the axis 11. The tube 14 extends into the housing 5 from the outflow opening 9. An inside 14.1 of the tube 14 is connected to the outflow opening 9 and is configured to duct air from an inside volume of the housing 5 to the outflow opening 9. An outside surface 14.2 of the tube 14 forms a partition wall which together with the inner wall 12 of the housing 5 forms a particle collecting space 16. The cyclone separator arrangement 1 comprises a second outlet 18 provided with a one-way valve 20. The one-way valve 20 allows flow of fluid and particles from the particle collecting space 16 to an outlet 20.1 of the one-way valve 20 and hinders flow of fluid in the opposite direction, i.e. through the outlet 20.1 of the one-way valve 20 into the dust collecting space 16. The outlet 20.1 of the one-way valve 20 may be connected to a dust container or may be connected to the environment outside of the cyclone separator arrangement 1.

During operation of the cyclone separator arrangement 1, fluid is flowing from the inflow opening 7 onto the guide blades 13. Due to the pitch angle a1 of the guide blades 13, a cyclone of fluid is formed around the axis 11. Due to the centrifugal force, particles in the fluid are forced towards the inner wall 12 of the housing. As a result thereof, fluid at the centre of the cyclone will contain less particles than fluid at outer portions of the cyclone. Accordingly, fluid that contains a lower amount of particles is ducted to the outflow opening 9, via the inside 14.1 of the tube 14, and fluid that contains a higher amount of particles is led to the second outlet 18 via the dust collecting space 16. The flow direction of the flow of fluid flowing from the inflow opening 7 towards the outflow opening 9 is indicated with the arrow d.

According to the illustrated embodiments, the cyclone separator arrangement 1 comprises a centre hub 21 coaxially arranged with respect to the axis 11, wherein the guide blades 13 are arranged on the centre hub 21 and extends radially from the centre hub 21.

Further, the cyclone separator arrangement 1 comprises a motor 15 configured to rotate the guide blades 13. According to the illustrated embodiments, the motor 15 is arranged inside the centre hub 21 and is configured to rotate the guide blades 13 around the axis 11 by rotating the centre hub 21. According to the illustrated embodiments, the motor is an electric motor, but may according to further embodiments comprise another type of motor such as a hydraulic motor or a pneumatic motor. The centre hub 21 with the motor 15 is arranged to the housing 5 via arms 22 arranged between the housing 5 and the centre hub 21. Electric wiring to the motor 15 is arranged in one of the arms 22.

Further, according to the illustrated embodiments, the cyclone separator arrangement 1 comprises a control arrangement 17 and a flow detecting unit 19. The flow detecting unit 19 is configured to detect the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. According to the illustrated embodiments, the flow detection unit 19 forms part of an engine control unit, as will be further explained below. According to further embodiments, the flow detecting unit 19 may comprise a sensor, such as a mass flow sensor, arranged at the inflow opening 7, the outflow opening 9, or inside the housing 5 between the inflow opening 7 and the outflow opening 9.

The control arrangement 17 is configured to control the rotational speed of the motor 15 in dependence of the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. Thereby, the rotational speed of the guide blades 13 is controlled in dependence of the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. The control arrangement 17 is configured to control the motor 15 to rotate the guide blades 13 in the first rotational direction d1 around the axis 11 when the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9 is below a first threshold value. Thereby, the angular velocity of the cyclone around the axis in the first rotational direction d1 is increased when the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9 is below the first threshold value. As a result, the separation efficiency of the cyclone separator arrangement 1 is increased when the flow rate of fluid flowing from the inflow opening towards the outflow opening is below the first threshold value.

Further, according to some embodiments, the control arrangement 17 is configured to control the rotational velocity of the at least one guide blade 13 in the first rotational direction d1 essentially inversely proportional to the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. Thereby, the control arrangement 17 will control the rotational velocity of the guide blades 13 such that the guide blades 13 rotates at a higher speed in the first rotational direction d1 when the flow rate is low and rotates at a lower speed when the flow rate is higher. As a result, a more consistent separation efficiency, as well as a more consistent pressure drop, is obtained at different flow rates of fluid flowing from the inflow opening 7 towards the outflow opening 9. Further, according to some embodiments, the pitch angle a1 of the guide blades 13 is optimized for a maximum flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. Thus, according to such embodiments, the pitch angle a1 of the guide blades 13 is such that the cyclone obtains an angular velocity, at the maximum flow rate of fluid, which provides a proper separation efficiency and a sufficiently low pressure drop over the cyclone separator arrangement 1. Accordingly, in such embodiments, the control arrangement 17 may control the rotational velocity of the guide blades 13 such that the guide blades 13 is at standstill when the flow rate is at the maximum flow rate of fluid and progressively increases the rotational velocity of the guide blades 13 upon decrease in flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. Thus, according to such embodiments, the control arrangement 17 may control the motor 15 to rotate in only one rotational direction and still adapt the separation efficiency and pressure drop within the full operational range of the cyclone separator arrangement 1. As examples, the pitch angle a1 may, according to such embodiments, be within the range of 35 - 55 degrees, or within the range of 40 - 50 degrees, or approximately 45 degrees. Herein the pitch angle a1 is defined as the angle a1 of the guide blades 13 in relation to a plane p perpendicular to the axis 11. The pitch angle a1 may vary along a radial direction r of the guide blades 13. According to such embodiments, the pitch angle a1 may be defined as the average pitch angle along the radial direction r of the guide blades 13 in relation to the plane p perpendicular to the axis 11.

According to further embodiments, the pitch angle a1 of the guide blades 13 is optimized for an intermediate flow rate being between the maximum flow rate and zero flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9, for example an intermediate flow rate within the range of 40 % - 60%, or approximately 50 %, of the maximum flow rate. Thus, according to these embodiments, the pitch angle a1 of the guide blades 13 is such that the cyclone obtains an angular velocity, at the intermediate flow rate of fluid, which provides a proper separation efficiency and a sufficiently low pressure drop over the cyclone separator arrangement 1. According to these embodiments, the control arrangement 17 may be configured to control the motor 15 to rotate the at least one guide blade 13 in a second rotational direction d2 around the axis 11, being opposite to the first rotational direction d1, when the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9 is above a second threshold value. The second threshold value may correspond to, or may be slightly higher than, the intermediate flow rate. Further, according to these embodiments, the first threshold value may correspond to, or may be lower higher than, the intermediate flow rate. As examples, the pitch angle a1 may, according to these embodiments, be within the range of 10 - 45 degrees, or within the range of 15 - 30 degrees, or approximately 22.5 degrees. Further, the control arrangement 17 may be configured to control the rotational velocity of the guide blades 13 in the second rotational direction d2 essentially proportional to the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. Thus, when the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9 is above the second threshold value, e.g. above the intermediate flow rate, the control arrangement 17 will, according to these embodiments, increase the rotational velocity of the guide blades 13, in the second rotational direction d2, upon an increase in flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. As a result, the pressure drop over the cyclone separator arrangement 1 is reduced at high flow rates. Thus, a more consistent pressure drop, as well as a more consistent separation efficiency, is obtained at different flow rates of fluid flowing from the inflow opening 7 towards the outflow opening 9. Further, when the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9 is below the first threshold value, e.g. below the intermediate flow rate, the control arrangement 17 will, according to these embodiments, increase the rotational velocity of the guide blades 13, in the first rotational direction d1, upon a decrease in flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. As a result, separation efficiency of the cyclone separator arrangement 1 is improved at lower flow rates. Thus, a more consistent separation efficiency, as well as a more consistent pressure drop, is obtained at different flow rates of fluid flowing from the inflow opening 7 towards the outflow opening 9. According to some embodiments, the first and second threshold values are the same and may correspond to the intermediate flow rate as defined above.

Fig. 2 illustrates a combustion engine 27 comprising an air intake arrangement 25. The air intake arrangement 25 is configured to duct ambient air to the combustion engine 27. The air intake arrangement 25 comprises the cyclone separator arrangement 1 illustrated in Fig. 1. The cyclone separator arrangement 1 is configured to separate particles from the air before the air is ducted to the combustion engine 27, where the air is led into cylinders of the combustion engine 27. The combustion engine 27 comprises an engine control unit 30. The engine control unit 30 is configured to control operation of the combustion engine 27. The engine control unit 30 comprises the flow detecting unit 19 illustrated in Fig. 1. The flow detecting unit 19 is arranged to obtain a current flowrate of gas flowing into cylinders of the combustion engine 27 from a flow sensor 26 arranged in an inlet manifold of the combustion engine 27. Thus, the control arrangement 17 illustrated in Fig. 1 may be configured to control the rotational speed of the motor 15 in dependence of a value representative of a current flowrate of gas obtained from the engine control unit 30, illustrated in Fig. 2.

The flow rate of the air ducted to the combustion engine 27 varies to a great extent. That is, during idling or during low load situations, the flow rate of air is low and during high load situations the flow rate of air is high. However, since the air intake arrangement 25 comprises the cyclone separator arrangement 1, the air intake arrangement 25 can adapt the separation efficiency and the pressure drop in dependence of the flow rate of ambient air ducted to the engine 27. Thus, an air intake arrangement 25 is provided with an improved separation efficiency at low load situations of the engine 27 and potentially with a lower pressure drop over the air intake arrangement 25 at high load situations of the engine 27. According to the illustrated embodiments, the air intake arrangement 25 further comprises a filter element 28. The filter element 28 is arranged downstream of the cyclone separator arrangement 1. Thus, according to the illustrated embodiments, the cyclone separator arrangement 1 is arranged to separate particles from the air before the air is ducted to the filter element 28 where the air is subjected to further filtering before being ducted to the combustion engine 27. Since the air intake arrangement 25 is provided with an improved separation efficiency at low load situations of the combustion engine 27, the dust accumulation in the filter element 28 can be reduced, the operational time of the filter element 28 can be increased, the demands on the filter element 28 can be reduced, a low prize filter element 28 can be used, a filter element 28 having a low pressure drop can be used, and droplets of liquids, such as water, can be separated from the air in a more efficient manner over a wider operational range which may enhance the performance of the filter element 28 and prolong the life time of the filter element 28.

The combustion engine 27 is an internal combustion engine and may be a compression ignition engine, such as a diesel engine, or may be an Otto engine with a spark-ignition device, for example an Otto engine designed to run on gas, petrol, alcohol, similar volatile fuels or combinations thereof.

Fig. 3 illustrates a vehicle 29 comprising wheels 31 and the combustion engine 27 illustrated in Fig. 2. The combustion engine 27 is configured to provide motive power to the vehicle 29 via one or more of the wheels 31 of the vehicle 29.

The vehicle 29 illustrated in Fig. 3 is a truck. However, the combustion engine 27 may be comprised in another type of manned or unmanned vehicle for land or water based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, a boat, a ship, or the like. Further, the combustion engine 27 as referred to herein may be a stationary combustion engine, for example a combustion engine configured to drive an electric generator.

The control arrangement 17 illustrated in Fig. 1, as well as the engine control unit 30 illustrated in Fig. 2, may comprise a calculation unit which may take the form of substantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression “calculation unit” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

The control arrangement 17 illustrated in Fig. 1, as well as the engine control unit 30 illustrated in Fig. 2, may further comprise a memory unit, wherein the calculation unit may be connected to the memory unit, which may provide the calculation unit with, for example, stored program code and/or stored data which the calculation unit may need to enable it to do calculations. The calculation unit may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

The engine control unit 30 illustrated in Fig. 2 is connected to components of the combustion engine 27 for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the engine control unit 30. These signals may then be supplied to the calculation unit. One or more output signal sending devices may be arranged to convert calculation results from the calculation unit to output signals for conveying to other parts of the vehicle's control system and/or the component or components for which the signals are intended. Each of the connections to the respective components of the combustion engine 27 for receiving and sending input and output signals may take the form of one or more from among a cable, a data bus, e.g. a CAN (controller area network) bus, a MOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection.

In the embodiments illustrated, the combustion engine 27 comprises an engine control unit 30 but might alternatively be implemented wholly or partly in two or more control arrangements or two or more control units.

Control systems in modern vehicles generally comprise a communication bus system consisting of one or more communication buses for connecting a number of electronic control units (ECUs), or controllers, to various components on board the vehicle. Such a control system may comprise a large number of control units and taking care of a specific function may be shared between two or more of them. Vehicles of the type here concerned are therefore often provided with significantly more control arrangements than depicted in Fig. 2, as one skilled in the art will surely appreciate.

It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions or groups thereof.

Claims

1. A cyclone separator arrangement (1) for separating particles from a flow of fluid, wherein the arrangement (1) comprises: - a housing (5) comprising an inflow opening (7) and an outflow opening (9) spaced apart along an axis (11), - at least one guide blade (13) rotationally arranged around the axis (11) between the inflow opening (7) and the outflow opening (9), wherein the at least one guide blade (13) extends radially with respect to the axis (11) and is provided with a pitch angle (a1) to provide a cyclone around the axis (11) when fluid is flowing from the inflow opening (7) towards the outflow opening (9), and - a motor (15) configured to selectively rotate the at least one guide blade (13) around the axis (11), characterized in that the arrangement (1) further comprises a control arrangement (17) and a flow detecting unit (19), wherein the flow detecting unit (19) is configured to detect the flow rate of fluid flowing from the inflow opening (7) towards the outflow opening (9), and wherein the control arrangement (17) is configured to control the rotational speed of the motor (15) in dependence of the flow rate of fluid flowing from the inflow opening (7) towards the outflow opening (9), wherein the at least one guide blade (13) is provided with a pitch angle (a1) to provide a cyclone having a first rotational direction (d1) around the axis (11) when fluid is flowing from the inflow opening (7) towards the outflow opening (9), wherein the control arrangement (17) is configured to control the motor (15) to rotate the at least one guide blade (13) in the first rotational direction (d1) around the axis (11) when the flow rate of fluid flowing from the inflow opening (7) towards the outflow opening (9) is below a first threshold value, and wherein the control arrangement (17) is configured to control the rotational velocity of the at least one guide blade (13) in the first rotational direction (d1) essentially inversely proportional to the flow rate of fluid flowing from the inflow opening (7) towards the outflow opening (9).

2. The arrangement (1) according to claim 1, wherein the control arrangement (17) is configured to control the motor (15) to rotate the at least one guide blade (13) in a second rotational direction (d2) around the axis (11), being opposite to the first rotational direction (d1), when the flow rate of fluid flowing from the inflow opening (7) towards the outflow opening (9) is above a second threshold value.

3. The arrangement (1) according to claim 2, wherein the control arrangement (17) is configured to control the rotational velocity of the at least one guide blade (13) in the second rotational direction (d2) essentially proportional to the flow rate of fluid flowing from the inflow opening (7) towards the outflow opening (9).

4. The arrangement (1) according to any one of the preceding claims, wherein the arrangement (1) comprises a centre hub (21) coaxially arranged with respect to the axis (11), wherein the at least one guide blade (13) is arranged at the centre hub (21) and extends radially therefrom.

5. The arrangement (1) according to claim 4, wherein the motor (15) is configured to rotate the centre hub (21).

6. The arrangement (1) according to claim 4 or 5, wherein the motor (15) is arranged inside the centre hub (21).

7. An air intake arrangement (25) for a combustion engine (27), wherein the air intake arrangement (25) is configured to duct ambient air to the combustion engine (27), and wherein the air intake arrangement (25) comprises a cyclone separator arrangement (1) according to any one of the preceding claims.

8. A combustion engine (27) comprising the air intake arrangement (25) according to claim 7.

9. The combustion engine (27) according to claim 8, wherein the combustion engine (27) comprises an engine control unit (30), wherein the cyclone separator arrangement (1) of the air intake arrangement (25) comprises a flow detecting unit (19), and wherein the flow detecting unit (19) forms part of the engine control unit (30).

10. A vehicle (29) comprising a combustion engine (27) according to claim 8 or 9.