WO2019054915A1

WO2019054915A1 - Cyclone separator and related devices

Info

Publication number: WO2019054915A1
Application number: PCT/SE2018/050897
Authority: WO
Inventors: Jonatan Bergström
Original assignee: Scania Cv Ab
Priority date: 2017-09-14
Filing date: 2018-09-07
Publication date: 2019-03-21
Also published as: DE112018004118T5; SE541337C2; DE112018004118B4; SE1751116A1

Abstract

Herein a cyclone separator (1) is disclosed for separating particles from a flow of fluid. The cyclone separator (1) comprises a housing (5) and at least one guide blade (13) arranged in the housing (5) between an inflow opening (7) and an outflow opening (9). The at least one guide blade (13) extends radially with respect to an axis (11) and is provided with a pitch angle (a0) to provide a cyclone around the axis (11). Each of the least one guide blade (13) comprises a blade portion (15) movably arranged between a first and second position. The blade portion (15) is biased towards the first position, and the blade portion (15) is configured to be moved from the first position towards the second position by the force of the flow of fluid acting on the blade portion (15). The present disclosure further relates to an air intake arrangement (25), a combustion engine (27), and a vehicle (29).

Description

Cyclone separator and Related Devices

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.

In addition, generally, today's consumer market requires high quality products that comprise different features and functions while the products have conditions for being manufactured in a cost-efficient manner.

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 first aspect of the invention, the object is achieved by a cyclone separator for separating particles from a flow of fluid. The cyclone separator comprises a housing comprising an inflow opening and an outflow opening spaced apart along an axis, and at least one guide blade arranged in the housing 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. Each of the least one guide blades comprise a blade portion movably arranged between a first position to provide a first pitch angle of the blade portion, and a second position to provide a second pitch angle of the blade portion, wherein the first pitch angle is smaller than the second pitch angle. The blade portion is biased towards the first position, and the blade portion is configured to be moved from the first position towards the second position by the force of the flow of fluid acting on the blade portion.

Since the blade portion is biased towards the first position, and is configured to be moved from the first position towards the second position by the force of the flow of fluid acting on the blade portion, a cyclone separator is provided capable of automatically adapting the pitch angle of the blade portion in dependence of the flow rate of fluid flowing from the inflow opening towards the outflow opening. That is, when the flow rate is low, there will be a low force of the flow of fluid acting on the blade portion. As a result, the blade portion will assume the first position in which the blade portion has a smaller pitch angle than when in the second position. Due to the smaller pitch angle, the flow of fluid will be subjected to a greater acceleration which causes a higher angular velocity of the cyclone than would be the case otherwise. Thus, the separation efficiency of the cyclone separator is improved at lower flow rates of fluid flowing through the cyclone separator. When the flow rate of fluid is higher, a higher force of the flow of fluid will act on the blade portion. As a result, the blade portion will be moved from the first position to a position where the blade portion has a greater pitch angle than the first pitch angle. Due to the greater pitch angle, the flow of fluid will be subjected to a lower amount of acceleration which causes a lower angular velocity of the cyclone than would be the case otherwise. As a result, the pressure drop over the cyclone separator is lowered at higher flow rates.

Accordingly, a cyclone separator is provided capable of adapting the separation efficiency and the pressure drop in dependence of the flow rate of fluid flowing from the inflow opening towards the outflow opening. Due to the adaptation of the separation efficiency and the pressure drop, 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. Further, the adaptation of the separation efficiency and the pressure drop is performed without having to use control arrangements, motors, or the like, which would have added manufacturing costs to the cyclone separator. Thus, a cyclone separator, capable of adapting the separation efficiency and the pressure drop, is provided which can be manufactured in a cost-efficient manner.

Accordingly, a cyclone separator 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 at least one guide blade comprises a first section with a fix pitch angle, and wherein the blade portion of the at least one guide blade is arranged at a trailing edge of the first section. Thereby, fluid will flow along the first section and obtain a circular motion causing a cyclone, and then flow along the blade portion which adapts the angular velocity of the cyclone and thereby also adapts the separation efficiency and the pressure drop in dependence of the flow rate. As a result, the separation efficiency and the pressure drop is adapted in a simple and effective manner.

Optionally, the first pitch angle of the blade portion is smaller than the fix pitch angle.

Thereby, the blade portion will accelerate the fluid to obtain a higher angular velocity of the cyclone to achieve a higher separation efficiency at lower flow rates of fluid flowing from the inflow opening towards the outflow opening.

Optionally, the second pitch angle of the blade portion is equal or greater than the fix pitch angle. Thereby, a cyclone separator is provided capable of reducing the pressure drop over the cyclone separator at high flow rates of fluid flowing from the inflow opening towards the outflow opening.

Optionally, the blade portion is hinged at the trailing edge of the first section. Thereby, a simple and reliable solution is provided for obtaining an adaptation of the separation efficiency and of the pressure drop in dependence of the flow rate of fluid flowing from the inflow opening towards the outflow opening.

Optionally, the cyclone separator further comprises at least one spring element, wherein the blade portion is biased towards the first position by the at least one spring element. Thereby, a simple and reliable solution is provided for obtaining an adaptation of the separation efficiency and of the pressure drop in dependence of the flow rate of fluid flowing from the inflow opening towards the outflow opening. Optionally, the blade portion is biased towards the first position by a biasing force being adapted to provide a pitch angle of the blade portion resulting in an essentially constant angular velocity of the cyclone around the axis at different flow rates of fluid from the inflow opening towards the outflow opening. Thereby, a cyclone separator is provided capable of achieving an essentially constant separation efficiency and an essentially constant pressure drop at different flow rates of fluid from the inflow opening towards the outflow opening.

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 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 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 having 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 is 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 is 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 is 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.

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, according to some embodiments, with blade portions thereof in a first position,

Fig. 2 illustrates the cyclone separator illustrated in Fig. 1 , with the blade portions in a second position,

Fig. 3 illustrates a combustion engine comprising an air intake arrangement, and

Fig. 4 illustrates a vehicle comprising the combustion engine illustrated in Fig. 3.

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 1 , according to some embodiments. The cyclone separator 1 is arranged to separate particles from a flow of fluid. The cyclone separator 1 comprises a housing 5 with an inflow opening 7 and an outflow opening 9 spaced apart along an axis 1 1 . According to the illustrated embodiments, the housing 5 is cylindrically shaped. The cyclone separator 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 1 according to the illustrated embodiments comprises eight guide blades 13, of which only seven are visible. The cyclone separator 1 may comprise another number of guide blades 13 than eight, for example 1 - 7, or 9 - 20, or the like. Thus, according to some embodiments, the cyclone separator 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 extends radially with respect to the axis 1 1 and is provided with a pitch angle aO to provide a cyclone around the axis 1 1 when fluid is flowing from the inflow opening 7 towards the outflow opening 9. Due to the cyclone around the axis 1 1 , 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 1 comprises a tube 14 coaxially arranged to the axis 1 1 . 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 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 1 .

During operation of the cyclone separator 1 , fluid is flowing from the inflow opening 7 onto the guide blades 13. Due to the pitch angle aO of the guide blades 13, a cyclone of fluid is formed around the axis 1 1 . Due to the centrifugal force, particles in the fluid are forced towards the inner wall 12 of the housing 5. 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 rotational direction rd of the cyclone around the axis 1 1 is indicated with the arrow rd, and the flow direction d 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 1 comprises a centre hub 14 coaxially arranged to the axis 1 1 . Each guide blade 13 is arranged at the centre hub 14 and extends radially therefrom. Each guide blade 13 may abut against, or may be attached to, the inner wall 12 of the housing 5. Further, according to such embodiments, the centre hub 14 may be arranged to the housing 5 via one or more guide blades 13.

Each of the guide blades 13 comprises a blade portion 15. The blade portion 15 of each guide blade 13 is movably between a first position and a second position. In Fig. 1 , the blade portions 15 are illustrated in the first position. In the first position, a first pitch angle a1 of the blade portions 15 is provided. As mentioned, the cyclone separator 1 may comprise one guide blade 13. According to such embodiments, the guide blade 13 may comprise one blade portion 15. However, for the reason of brevity and clarity, the blade portion 15 according to such embodiments is below referred to as "the blade portions 15". Fig. 2 illustrates the cyclone separator illustrated in Fig. 1 with the blade portions 15 in the second position. In the second position, a second pitch angle a2 of the blade portions 15 is provided. Below, reference is made to Fig. 2, as well as to Fig. 1 . As seen when comparing Fig. 1 and Fig. 2, the first pitch angle a1 is smaller than the second pitch angle a2. The blade portions 15 are biased towards the first position. The blade portions 15 are configured to be moved from the first position, illustrated in Fig. 1 , towards the second position, illustrated in Fig. 2, by the force of the flow of fluid acting on the blade portion 15. As a result, a cyclone separator 1 is provided capable of automatically adapting the pitch angle of the blade portions 15 in dependence of the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. That is, when the flow rate is low or zero, there will be a low force, or no force, of flow of fluid acting on the blade portions 15. As a result, the blade portions 15 will be in the first position, as illustrated in Fig.1 . According to some embodiments, the blade portions 15 are configured to be moved from the first position, towards the second position, by the force of the flow of fluid acting on the blade portions 15, when the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9 is above a predetermined threshold value. Thus, according to such embodiments, the blade portions 15 will be in the first position when the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9 is below the predetermined threshold value.

As mentioned, the first pitch angle a1 is smaller than the second pitch angle a2. Due to the smaller pitch angle, the flow of fluid will be subjected to a greater acceleration which causes a higher angular velocity of the cyclone when the blade portions 15 are in the first position than when the blade portions 15 are in the second position, or in a position between the first and second positions. As a result of the higher angular velocity of the cyclone, the separation efficiency of the cyclone separator 1 is improved at lower flow rates.

When the flow rate of fluid is higher, e.g. above the predetermined threshold value, a higher force of the flow of fluid will act on the blade portions 15. As a result, the blade portions 15 will be moved from the first position to a position where the blade portions 15 each has a greater pitch angle than the first pitch angle a1 . Due to the greater pitch angle, the flow of fluid will be subjected to a lower amount of acceleration which causes a lower angular velocity of the cyclone than when the blade portions 15 are in the first position. Thereby, the pressure drop over the cyclone separator 1 is lowered at higher flow rates. Further, a cyclone separator 1 is provided capable of adapting the separation efficiency and the pressure drop in dependence of the flow rate of fluid flowing from the inflow opening 7 towards the outflow opening 9. According to the illustrated embodiments, the guide blades 13 each comprises a first section 17 with a fix pitch angle aO. Further, the blade portions 15 are arranged at a trailing edge 19 of the first sections 17 of the guide blades 13.

As seen in Fig. 1 , the first pitch angle a1 of the blade portions 15 is smaller than the fix pitch angle aO. Thereby, at lower flow rates of fluid flowing from the inflow opening 7 towards the outflow opening 9, the blade portions 15 will accelerate the circular motion of the fluid flowing along the guide blades 13. As a result, a higher angular velocity of the cyclone is provided which results in a higher separation efficiency at lower flow rates.

According to the illustrated embodiments, and as seen in Fig. 2, the second pitch angle a2 of is equal to the fix pitch angle aO. Thereby, the pressure drop over the cyclone separator 1 can be lowered at higher flow rates. According to further embodiments, the second pitch angle a2 may be greater than the fix pitch angle aO. Thereby, the pressure drop over the cyclone separator 1 can be further lowered at higher flow rates. Purely as examples, the fix pitch angle aO may be within the range of 35 - 55 degrees, or within the range of 40 - 50 degrees, or approximately 45 degrees, the first pitch angle a1 may be within the range of 5 - 30 degrees, or within the range of 15 - 25 degrees, or approximately 20 degrees, the second pitch angle a2 may be within the range of 35 - 70 degrees, or within the range of 40 - 55 degrees, or approximately 45 degrees. Herein the first and second pitch angles a1 , a2 are defined as the angle a1 , a2 of the blade portions 15 in relation to a plane p perpendicular to the axis 1 1 . Further, herein the fix pitch angle aO is defined as the angle aO of the guide blades 13 in relation to a plane p perpendicular to the axis 1 1 . The fix pitch angle aO, and/or the first and second pitch angle a1 , a2, may vary along a radial direction r of a blade 13, 15. According to such embodiments, the pitch angle aO, a1 , a2 may be defined as the average pitch angle along the radial direction r of a blade 13, 15 in relation to the plane p

perpendicular to the axis 1 1 . According to the illustrated embodiments, each blade portion 15 is hinged at a trailing edge 19 of the first section 17. Further, the cyclone separator 1 comprises spring elements 21 , wherein each blade portion 15 is biased towards the first position by a spring element 21 . Thereby, the adaptation of the angular velocity of the cyclone, and thus also the separation efficiency and the pressure drop over the cyclone separator 1 , is achieved in a simple and effective manner. The spring elements 21 may, as is the case according to the illustrated embodiments, be arranged between a trailing edge 19 of a first section 17 and a blade portion 15. Each spring element 21 may comprise a flexible material that biases a blade portion 15 towards the first position, when the blade portion 15 is displaced therefrom.

According to the illustrated embodiments, the blade portions 15 are biased towards the first position by a biasing force that is adapted to provide a pitch angle of the blade portions 15 resulting in an essentially constant angular velocity of the cyclone around the axis 1 1 at different flow rates of fluid from the inflow opening 7 towards the outflow opening 9. As a result, a cyclone separator 1 is provided capable of achieving an essentially constant separation efficiency and an essentially constant pressure drop at different flow rates of fluid flowing from the inflow opening 7 towards the outflow opening 9. The essentially constant angular velocity of the cyclone around the axis 1 1 at different flow rates may be obtained by using spring elements 21 having spring characteristics matched with the flow characteristics of the blade portions 15. According to some embodiments, the blade portions 15 are biased towards the first position by a biasing force that increases upon displacement of the blade portions 15 from the first position towards the second position. Thereby the blade portions 15 may easier assume a position between the first and second positions. As a further result thereof, the ability to obtain an essentially constant angular velocity of the cyclone around the axis 1 1 at different flow rates can be improved. According to some embodiments, the blade portions 15 constitute the entire surface of the guide blades 13. Thus, according to such embodiments, the guide blades 13 may each lack a first section 17 with a fix pitch angle aO as referred to herein. Instead, according to such embodiments, the guide blades 13 may be movably arranged between a first position to provide a first pitch angle a1 , and a second position to provide a second pitch angle a2, of the guide blades 13, wherein the first pitch angle a1 is smaller than the second pitch angle a2, wherein guide blades 13 are biased towards the first position, and wherein the guide blades 13 are configured to be moved from the first position towards the second position by the force of the flow of fluid acting on the guide blades 13. Fig. 3 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 1 illustrated in Fig. 1 and Fig. 2. The cyclone separator 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 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 1 , the air intake arrangement 25 is capable of adapting 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 1 . Thus, according to the illustrated embodiments, the cyclone separator 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. 4 illustrates a vehicle 29 comprising wheels 31 and the combustion engine 27 illustrated in Fig. 3. 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. 4 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.

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 (1 ) for separating particles from a flow of fluid, wherein the cyclone separator (1 ) comprises:

- a housing (5) comprising an inflow opening (7) and an outflow opening (9) spaced apart along an axis (1 1 ), and

- at least one guide blade (13) arranged in the housing (5) 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 (1 1 ) and is provided with a pitch angle (aO) to provide a cyclone around the axis (1 1 ) when fluid is flowing from the inflow opening (7) towards the outflow opening (9),

wherein each of the least one guide blade (13) comprises a blade portion (15) movably arranged between a first position to provide a first pitch angle (a1 ) of the blade portion (15), and a second position to provide a second pitch angle (a2) of the blade portion (15), wherein the first pitch angle (a1 ) is smaller than the second pitch angle (a2),

characterized in that the blade portion (15) is biased towards the first position, and wherein the blade portion (15) is configured to be moved from the first position towards the second position by the force of the flow of fluid acting on the blade portion (15).

2. The cyclone separator (1 ) according to claim 1 , wherein the at least one guide blade (13) comprises a first section (17) with a fix pitch angle (aO), and wherein the blade portion (15) of the at least one guide blade (13) is arranged at a trailing edge (19) of the first section (17).

3. The cyclone separator (1 ) according to claim 2, wherein the first pitch angle (a1 ) of the blade portion (15) is smaller than the fix pitch angle (aO).

4. The cyclone separator (1 ) according to claim 2 or 3, wherein the second pitch angle (a2) of the blade portion (15) is equal or greater than the fix pitch angle (aO).

5. The cyclone separator (1 ) according to any one of the claims 2 - 4, wherein the blade portion (15) is hinged at the trailing edge (19) of the first section (17).

6. The cyclone separator (1 ) according to any one of the preceding claims, further

comprising at least one spring element (21 ), wherein the blade portion (15) is biased towards the first position by the at least one spring element (21 ).

7. The cyclone separator (1 ) according to any one of the preceding claims, wherein the blade portion (15) is biased towards the first position by a biasing force being adapted to provide a pitch angle of the blade portion (15) resulting in an essentially constant angular velocity of the cyclone around the axis (1 1 ) at different flow rates of fluid from the inflow opening (7) towards the outflow opening (9).

8. 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 (1 ) according to any one of the preceding claims.

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

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