WO2019185548A1

WO2019185548A1 - A cooling arrangement for a combustion engine

Info

Publication number: WO2019185548A1
Application number: PCT/EP2019/057443
Authority: WO
Inventors: Tommy SHOUG; Jonas CLAAR; Anders Hansson; Freddie LINDEGREN
Original assignee: Husqvarna Ab
Priority date: 2018-03-27
Filing date: 2019-03-25
Publication date: 2019-10-03
Also published as: DE112019001550T5; SE1850338A1

Abstract

An air injection arrangement (101) for a combustion engine too comprising a combustion engine module (150). The air injection arrangement (101) comprises an air inlet (195) arranged to guide air into a main air channel (220) at an air pressure. The main air channel comprises a branch into a first air channel and a second air channel. The first air channel is arranged to be connected to an air intake of the combustion engine, and the second air channel is arranged to be connected to an air flow conduit for cooling the combustion engine module.

Description

A COOLING ARRANGEMENT FOR A COMBUSTION ENGINE

TECHNICAL FIELD

This disclosure relates to cooling arrangements and methods for cooling combustion engine modules. The cooling arrangements and methods are especially suited for cooling fuel injectors in two-stroke engines.

BACKGROUND

A traditional combustion engine uses a carburetor to mix fuel and air in an appropriate mixture for combustion in a combustion chamber of the engine. Such traditional carburetor designs can be replaced by fuel injectors that inject fuel in a controlled amount for combustion in the combustion chamber. Potential benefits of fuel injection compared to carburetor designs include, e.g., better fuel efficiency and also reduced emissions.

A special type of combustion engine design comprises a crankcase mounted fuel injector. Here, the fuel injector injects fuel directly into the engine crankcase, where the fuel is mixed with air by the operation of the crankshaft. However, heat from the crankcase is transferred to the crankcase mounted fuel injector. If the fuel injector becomes too hot, vapor lock may occur, i.e., the fuel may change state to gas form, which causes problems during fuel injection. A crankcase mounted fuel injector may therefore require cooling.

Crank-case mounted fuel injectors may be cooled by separate air-fan arrangements, which separate air-fan arrangements add cost and complexity. Air-cooling arrangements for cooling combustion engine modules in construction equipment, such as motor saws and cutoff machines, operate in environments where unwanted particles, e.g., saw-dust or concrete debris, may obstruct air filters and cause other problems.

US 2014/0299098 Ai describes an internal combustion engine for a cutoff machine which implements a crankcase mounted fuel injection system.

There is a need for a cooling arrangement for cooling fuel injectors and other combustion engine modules which is cost efficient and able to function in environments with high particle levels. SUMMARY

It is an object of the present disclosure to provide cooling arrangements for cooling fuel injectors and other combustion engine modules which is cost efficient and able to function in environments with high particle levels. This object is achieved by an air injection arrangement for a combustion engine. The combustion engine comprises a combustion engine module. The air injection arrangement comprises an air inlet arranged to guide air into a main air channel at an air pressure, the main air channel comprising a branch into a first air channel and a second air channel, wherein the first air channel is arranged to be connected to an air intake of the combustion engine, and the second air channel is arranged to be connected to an air flow conduit for cooling the combustion engine module. This way, a single component is used for two purposes; cooling the combustion engine module and providing air for the air intake of the combustion engine. According to aspects, the combustion engine module is a crankcase mounted fuel injector arranged to inject fuel into a crankcase of the combustion engine. Consequently, the crankcase mounted fuel injector is cooled in an efficient and cost-effective manner.

According to aspects, the air inlet is arranged close to an outer edge of wings on a fan wheel associated with the combustion engine, thereby generating the air pressure and reducing an amount of unwanted particles entering the air inlet. This feature provides for a reduced amount of unwanted particles entering the combustion engine, while providing efficient cooling for the combustion engine module.

According to aspects, the air flow conduit for cooling the combustion engine module is arranged as a separate channel external to the crankcase. This way no major modifications of the crankcase are needed.

According to aspects, the air flow conduit for cooling the combustion engine module is a machined channel in an enclosing material of the crankcase. By machining the channel into the crankcase enclosing material, a robust channel is obtained, and the amount of parts is not increased. According to aspects, the air inlet, the main air channel, and the branch are integrally formed as a single component. Thereby a cost-efficient manufacturing and assembly process is enabled.

There is also disclosed herein a hand-held construction machine, a handheld power tool, and a chainsaw comprising the air injection arrangement discussed herein.

The object is also achieved by an air injection arrangement for a combustion engine comprising a combustion engine module. The arrangement comprises a first air inlet arranged to guide air into a first air channel at a first air pressure, a second air inlet arranged to guide air into a second air channel at a second air pressure, wherein each of the first air inlet and the second air inlet is arranged close to an outer edge of wings on a fan wheel associated with the combustion engine, thereby generating the first air pressure and the second air pressure, and reducing an amount of unwanted particles entering the air inlet, wherein the first air channel is arranged to be connected to an air intake of the combustion engine, and the second air channel is arranged to be connected to an air flow conduit for cooling the combustion engine module.

The object is furthermore achieved by an air intake component for mounting close to an outer edge of wings on a fan wheel. The fan wheel being associated with a combustion engine, the component comprising an air inlet arranged to guide air into a main air channel at an air pressure. The main air channel comprises a branch into a first air channel and into a second air channel. The first air channel is arranged to be connected to an air intake of the combustion engine. The second air channel is arranged to be connected to an air flow conduit for cooling the combustion engine module, wherein the air inlet, the main air channel, and the branch are integrally formed as a single component.

There are also disclosed herein methods associated with the above mentioned advantages.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated .

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:

Figure l schematically shows a combustion engine;

Figure 2 illustrates an air injection arrangement;

Figure 3 shows a side view of a machine comprising a fan;

Figure 4 illustrates a side wall of an air intake;

Figure 5 schematically shows a combustion engine;

Figure 6 is a flow chart illustrating methods;

Figure 7 is a flow chart illustrating methods; and

Figure 8 schematically illustrates an air intake component.

DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.

Fig. 1 schematically shows a combustion engine 100. The combustion engine comprises a cylinder no in which a piston 120 is arranged to reciprocate in a known manner. The reciprocating motion, in an upwards direction U and in a downwards direction D, of the piston is transferred to a circular motion by means of a crankshaft 140 arranged in a crankcase 130. As the piston 120 moves in the upward direction U, a conduit between an air intake 165 of the combustion engine and the crankcase 130 is opened, whereby air enters the crankcase. The air intake 165 is arranged in an air intake module 160, which, according to aspects, comprises a throttle valve to regulate the air intake, and an air filter.

The combustion engine 100 comprises a combustion engine module 150, here shown as a crankcase mounted fuel injector. Consequently, according to aspects, the combustion engine module 150 is a crankcase mounted fuel injector arranged to inject fuel 155 into a crankcase 130 of the combustion engine 100.

The fuel injector is arranged to inject fuel 155 into the crankcase 130 at a specific time instant. Thereby, the fuel is mixed with the air from the air intake 165 into a fuel/air mixture by the operation of the crankshaft 140.

As the piston 120 reciprocates to move in the downward direction D, the air/fuel mixture 156 in the crankcase is forced via a crossflow channel 170 into the cylinder 110. A spark plug 125 ignites the fuel/air mixture at an appropriate time instant, which ignition forces the piston in the downward direction D again, and the process repeats.

The combustion engine 100 illustrated in Fig. 1 comprises a novel air injection arrangement 101 which supplies air to the combustion engine. The air injection arrangement 101 comprises an air inlet 195 arranged to guide air into a main air channel of the air injection arrangement at an air pressure. How this air pressure is obtained will be discussed in more detail below in connection to Fig. 3 and Fig. 4.

The main air channel comprises a branch 190 into a first air channel and into a second air channel. The first air channel is arranged to be connected to the air intake 165 of the combustion engine 100, while the second air channel is arranged to be connected to an air flow conduit 180 for cooling the combustion engine module 150.

Due to the air pressure, air will flow from the air flow conduit 180. This air flow will transport heat away from any combustion engine module 150 it contacts. In particular, the air flow will cool a crankcase mounted fuel injector, thereby preventing temperature related problems such as vapor lock.

It is appreciated that other combustion engine modules may be arranged to be cooled in the same way as the crankcase mounted fuel injector.

The combustion engine too shown in Fig. l is, according to aspects, a two- stroke combustion engine. Such engines are commonly used for, e.g., handheld construction equipment, such as motor saws and cutoff machines. Consequently, there is disclosed herein a hand-held or otherwise operated construction machine comprising the air injection arrangement according to the discussion herein.

The dimensions of the first and of the second air channel, according to aspects, are arranged with different cross-section area. This way the two air-flows in the different channels transport different amounts of air and or at different flow rates. In some engines the air intake 165 requires a larger quantity of air compared to the cooling of the combustion engine module 150. Therefore, according to some aspects, a cross-section area of the first air channel 240 is larger than a cross-section area of the second air channel 250.

The air flow conduit 180 may be arranged in different ways to achieve the effect of cooling the combustion engine module 150. As long as the air conduit transports air from the main air channel to the combustion engine module, cooling is achieved.

According to one implementation example, the air flow conduit 180 for cooling the combustion engine module 150 is arranged as a separate channel external to the crankcase 130. This channel may for instance be a plastic channel connected to the branch 190 and arranged to guide air towards the combustion engine module 150.

According to another implementation example, the air flow conduit 180 for cooling the combustion engine module 150 is a machined channel in an enclosing material of the crankcase 130.

The cooling air may be arranged to blow onto the combustion engine module and/or onto a cooling flange arrangement of the combustion engine module. The cooling air passing through the air flow conduit 180 may also be used in a heat exchanger for transporting heat away from the combustion engine module.

It is appreciated that the air flow conduit 180 may be arranged partly as a plastic channel, and partly as a machined channel in the crankcase. It is furthermore appreciated that both types of channels may be used in parallel.

According to some aspects, the air flow in the first and in the second air channel is arranged to be regulated by means of a throttle valve or other air flow regulating means. A control unit may then optimize the different air flow volumes depending on circumstances. For instance, the cooling requirements of a fuel injector at cold start may be lower than during combustion engine operation at high load. Consequently, any of the first air channel 240 and the second air channel 250 comprises a throttle arranged to regulate an air flow passing through the first and through the second air channel, respectively. There is furthermore disclosed herein a control unit arranged to control the throttles according to a set of pre-determined control rules. The control rules can be determined a-priori by, e.g., laboratory experiments and/or computer simulation.

Fig. 2 illustrates an air injection arrangement 101. The air injection arrangement discussed above may be advantageously and cost efficiently formed as a single component. The air inlet 195, the main air channel 220, and the branch 190 are then, according to aspects, integrally formed as a single component. This single component may be a plastic component obtained by, e.g., molding, or a metal component obtained by, e.g., machining or molding. The single component may also be manufactured as a combination of metal and plastic.

According to some aspects, the single component comprises the air flow conduit 180. Thus, an efficient cooling means for, e.g., a crankcase mounted fuel injector is obtained without introducing a plurality of different components to be assembled during manufacturing. Rather, a single component is used both for supplying combustion air and for cooling various combustion engine modules, such as a crankcase mounted fuel injector. It is appreciated that several different combustion engine modules may require cooling. It is furthermore appreciated that a combustion engine may comprise several crankcase mounted fuel injectors.

According to some aspects, the branch 190 is arranged to branch into the first air channel, and into a plurality of second air channels. This way the plurality of second air channels can be used to cool a plurality of different combustion engine modules.

According to some aspects, the plurality of second air channels are used to cool a single combustion engine module. For instance, a more efficient cooling of a crankcase mounted fuel injector can be obtained by blowing air onto the injector from several different directions concurrently.

Thus, there is disclosed herein an air injection arrangement, wherein the branch 190 branches into a plurality of second 250 air channels, for cooling a plurality of combustion engine modules. Such a plurality of second air channels are not shown in any of the Figures.

Fig. 3 shows a side view of a machine comprising a fan. Only a section 10 of the machine body is illustrated in the figure. A fan cover surrounding the claimed arrangement is not illustrated in the figure. The section 10 comprises a fan housing 11 and a fan wheel 12. The fan wheel 12 is rotating around an axle 15 and provided with a number of wings 13. The wings are S-shaped, as an example, and extending in substantially radial direction on the fan wheel. Each wing 13 has an outer edge 16 substantially parallel to the axle 15 of rotation. Close to the periphery of the fan wheel 12 an air inlet 14 is placed. The air inlet 14 is positioned so that the air inlet 14 will collect a substantial amount of air, thus generating an air pressure into the intake. A large amount of the generated air stream is rotating around the periphery of the fan wheel 12 in the fan housing 11. The air inlet 14 is therefore placed so that the air inlet 14 exposes a large area perpendicular to the direction of the air stream.

The air inlet is placed as close to the outer edges of the wings as possible since the amount of pollutants is lower towards the outer edge of the wings. The air inlet must however be placed so that it never gets in contact with a wing. According to aspects, the side of the air inlet is placed at a distance of l to to millimeters from the edge of the wings.

Thus, in order to provide the air pressure into the main air channel, the air inlet 14 is, according to aspects, arranged close to an outer edge the wings 13 on the fan wheel 12 associated with the combustion engine 100. This way, air pressure is generated at the same time as the amount of unwanted particles entering the air inlet 14 is reduced.

According to an example, the distance between the air inlet 14 and the outer edge of the wings 13 is below 10mm.

The air inlet 14 is positioned somewhere around the fan wheel 12. The position of the air inlet 14 around the fan wheel 12 does not affects the performance of the air intake. It is appreciated that several separate air intakes make be arranged around the fan wheel.

With reference also to Fig. 2, there is disclosed herein an air intake component 200 for mounting close to an outer edge of wings 13 on a fan wheel 12. The fan wheel is associated with a combustion engine 100. The air intake component 200 comprises an air inlet 195 arranged to guide air into a main air channel 220 at an air pressure. The main air channel comprises a branch 190 into a first air channel 240 and into a second air channel 250. The first air channel 240 is arranged to be connected to an air intake 165 of the combustion engine 100. The second air channel 250 is arranged to be connected to an air flow conduit 180 for cooling the combustion engine module 150. The air inlet 14, the main air channel 220, and the branch 190 are integrally formed as a single component.

Fig. 4 schematically illustrates a side wall of the air intake 14. The air inlet 14 comprises four substantially straight sides. The side 17 of the air inlet 14 placed closest to the outer edge 16 of the wings 13 is, according to some aspects, angled in relation to the outer edge 16 of the wings 13. The angle, denoted in Fig. 4 as angle b, between the outer edge 16 of the wing 13 and the side 17 of the air inlet is preferably between io° and 6o°.

According to an implementation example, the side 17 closest to the outer edge 16 of the wing 13 is substantially parallel to the outer edge 16 of the wing 13 no matter of the angle of t e outer edge 16 so that the small gap between the side 17 of the air inlet 13 and the outer edge 16 of the wing 13 has a substantially constant width.

This arrangement reduces the sound generated in the fan considerably, since only a small section of the outer edge of the wing will meet a small section of the angled side of the air inlet at a specific moment when the fan wheel is rotating.

According to aspects, the side of the air inlet is arranged such that the side will extend over at least two wings on the fan wheel, which has an even stronger sound reducing effect.

In summary, according to aspects, there is disclosed in Fig. 4 an air injection arrangement 101 arranged to expose an area perpendicular to a direction A of an air stream of the fan wheel 12. The air inlet 14 comprising four sides, wherein a side 17 of the air inlet 14 placed closest to the outer edge 16A, 16B of the wings 13 is arranged at an angle b in relation to the outer edge 16A, 16B of the wings 13. According to an example, the angle b between the outer edge 16A of the wing 13 and the side 17 of the air inlet is between io° to 60

It is noted that the air inlet is shown as 195 in Fig. 2, and as 14 in Fig. 3 and in Fig. 4.

Fig. 5 schematically shows a combustion engine with a plurality of separate air intakes. In particular, there is shown an air injection arrangement 601 for a combustion engine 600 comprising a combustion engine module 150. The arrangement comprises a first air inlet 195A arranged to guide air into a first air channel at a first air pressure, and a second air inlet 195B arranged to guide air into a second air channel at a second air pressure. Each of the first air inlet 195A and the second air inlet 195B is arranged close to an outer edge of wings 13 on a fan wheel 12 associated with the combustion engine, thereby generating the first air pressure and the second air pressure, and also reducing an amount of unwanted particles entering the air inlet 14. The first air channel is arranged to be connected to an air intake 165 of the combustion engine, and the second air channel is arranged to be connected to an air flow conduit 180 for cooling the combustion engine module 150. The above discussed techniques for cooling one or more combustion engine modules may also be formulated as methods. Fig. 6 is a flow chart illustrating such methods. Fig. 6 shows a method for cooling a combustion engine module 150 in a combustion engine 100. The method comprises configuring Si an air inlet 14, 195 to guide a main air flow into a main air channel 220 at an air pressure, dividing S2 the main air flow into a first air flow and a second air flow, feeding S3 the first air flow to an air intake 165 of the combustion engine 100, and directing S4 the second air flow into an air flow conduit 180 for cooling the combustion engine module 150.

Fig. 7 is a flow chart illustrating other such methods. Fig. 7 shows a method for cooling a combustion engine module 150 in a combustion engine 600. The method comprises configuring Sal a first air inlet 195A to guide air into a first air channel at a first air pressure, configuring Sa2 a second air inlet 195B to guide air into a second air channel at a second air pressure. Each of the first air inlet 195A and the second air inlet 195B is configured close to an outer edge of wings 13 on a fan wheel 12 associated with the combustion engine 600, thereby generating the first air pressure and the second air pressure, and reducing an amount of unwanted particles entering the air inlet 14. The method also comprises feeding Sa3 the first air flow to an air intake 165 of the combustion engine, and directing Sa4 the second air flow into an air flow conduit 180 for cooling the combustion engine module 150.

Figure 8 schematically illustrates an air intake component 200 for mounting close to an outer edge of wings 13 on a fan wheel, the fan wheel being associated with a combustion engine. The component 200 comprising an air inlet 195 arranged to guide air into a main air channel 220 at an air pressure, the main air channel comprising a branch 190 into a first air channel 240 and into a second air channel 250, the first air channel 240 is arranged to be connected to an air intake of the combustion engine, the second air channel 250 is arranged to be connected to an air flow conduit for cooling the combustion engine module, wherein the air inlet 195, the main air channel 220, and the branch 190 are integrally formed as a single component. It is noted that the drawing in Fig. 8 only schematically illustrates the air intake component, and is not to scale. The figure merely serves to illustrate the concept of the disclosed air intake component.

Claims

1. An air injection arrangement (101) for a combustion engine (too), the combustion engine comprising a combustion engine module (150), the air injection arrangement (101) comprising;

an air inlet (14, 195) arranged to guide air into a main air channel (220) at an air pressure,

the main air channel (220) comprising a branch (190) into a first air channel (240) and a second air channel (250), wherein

the first air channel (240) is arranged to be connected to an air intake (165) of the combustion engine (100), and

the second air channel (250) is arranged to be connected to an air flow conduit (180) for cooling the combustion engine module (150).

2. The air injection arrangement (101) according to claim 1, wherein the combustion engine module (150) is a crankcase mounted fuel injector arranged to inject fuel (155) into a crankcase (130) of the combustion engine (100).

3. The air injection arrangement (101) according to any previous claim, wherein the combustion engine (101) is a two-stroke combustion engine.

4. The air injection arrangement (101) according to any previous claim, wherein the air inlet (14) is arranged close to an outer edge of wings (13) on a fan wheel (12) associated with the combustion engine (100), thereby generating the air pressure and reducing an amount of unwanted particles entering the air inlet (14).

5. The air injection arrangement (101) according to claim 4, arranged to expose an area perpendicular to a direction (A) of an air stream of the fan wheel

(12), the air inlet (14) comprising four sides, wherein a side (17) of the air inlet (14) placed closest to the outer edge (16A, 16B) of the wings (13) is arranged at an angle (b) in relation to the outer edge (16A, 16B) of the wings (13)

6. The air injection arrangement (101) according to claim 5, wherein the angle (b) between the outer edge (16A) of the wing (13) and the side (17) of the air inlet is between io° to 60

7. The air injection arrangement (101) according to any of claim 4-6, wherein a distance between the air inlet (14,195) and the outer edge of the wings (13) is below 10mm.

8. The air injection arrangement (101) according to any previous claim, wherein a cross-section area of the first air channel (240) is larger than a cross- section area of the second air channel (250).

9. The air injection arrangement (101) according to any previous claim, wherein the air flow conduit (180) for cooling the combustion engine module (150) is arranged as a separate channel external to the crankcase (130).

10. The air injection arrangement (101) according to any previous claim, wherein the air flow conduit (180) for cooling the combustion engine module (150) is a machined channel in an enclosing material of the crankcase (130).

11. The air injection arrangement (101) according to any previous claim, wherein any of the first air channel (240) and the second air channel (250) comprises a throttle arranged to regulate an air flow passing through the first and through the second air channel, respectively.

12. The air injection arrangement (101) according to any previous claim, wherein the air inlet (14,195), the main air channel (220), and the branch (190) are integrally formed as a single component.

13. The air injection arrangement (101) according to claim 12, wherein the single component is a molded plastic component.

14. The air injection arrangement (101) according to claim 12, wherein the single component is a machined or molded metal component.

15. The air injection arrangement (101) according to any of claims 12-14, wherein the single component comprises the air flow conduit (180).

16. The air injection arrangement (101) according to any previous claim, wherein the branch (190) branches into a plurality of second (250) air channels, for cooling a plurality of combustion engine modules.

17. A hand-held construction machine comprising the air injection arrangement according to any previous claim.

18. A handheld power tool comprising the air injection arrangement according to any of claims 1-16.

19. A chainsaw comprising the air injection arrangement according to any of claims 1-16.

20. An air injection arrangement (601) for a combustion engine (600) comprising a combustion engine module (150), the arrangement comprising; a first air inlet (195A) arranged to guide air into a first air channel at a first air pressure,

a second air inlet (195B) arranged to guide air into a second air channel at a second air pressure, wherein

each of the first air inlet (195A) and the second air inlet (195B) is arranged close to an outer edge of wings (13) on a fan wheel (12) associated with the combustion engine (600), thereby generating the first air pressure and the second air pressure, and reducing an amount of unwanted particles entering the air inlet (14), wherein

the first air channel is arranged to be connected to an air intake (165) of the combustion engine (600), and

the second air channel is arranged to be connected to an air flow conduit (180) for cooling the combustion engine module (150).

21. An air intake component (200) for mounting close to an outer edge of wings (13) on a fan wheel (12), the fan wheel being associated with a combustion engine (100), the component (200) comprising an air inlet (195) arranged to guide air into a main air channel (220) at an air pressure, the main air channel comprising a branch (190) into a first air channel (240) and into a second air channel (250), the first air channel (240) is arranged to be i6 connected to an air intake (165) of the combustion engine (100), the second air channel (250) is arranged to be connected to an air flow conduit (180) for cooling the combustion engine module (150), wherein the air inlet (14,195), the main air channel (220), and the branch (190) are integrally formed as a single component.

22. A method for cooling a combustion engine module (150) in a combustion engine (100), the method comprising;

configuring (Si) an air inlet (14, 195) to guide a main air flow into a main air channel (220) at an air pressure,

dividing (S2) the main air flow into a first air flow and a second air flow, feeding (S3) the first air flow to an air intake (165) of the combustion engine (100), and

directing (S4) the second air flow into an air flow conduit (180) for cooling the combustion engine module (150).

23. A method for cooling a combustion engine module (150) in a combustion engine (100), the method comprising;

configuring (Sal) a first air inlet (195A) to guide air into a first air channel at a first air pressure,

configuring (Sa2) a second air inlet (195B) to guide air into a second air channel at a second air pressure,

wherein each of the first air inlet (195A) and the second air inlet (195B) is configured close to an outer edge of wings (13) on a fan wheel (12) associated with the combustion engine (100), thereby generating the first air pressure and the second air pressure, and reducing an amount of unwanted particles entering the air inlet (14),

feeding (Sa3) the first air flow to an air intake (165) of the combustion engine (100), and

directing (Sa4) the second air flow into an air flow conduit (180) for cooling the combustion engine module (150).