DE102022001192A1 - AIR INTAKE SYSTEM WITH PREFILTER FOR A DRIVE OF A VEHICLE - Google Patents

Abstract

Air intake system (3) of a drive (2) of a vehicle (1). The air intake system (3) has the following: at least one air inlet (4); an intake duct (5) adapted to connect the air intake (4) to the engine (2); and a secondary air filter (10) arranged along the intake duct (5) and provided with a peripheral frame (11) and with a single cloth (12) mounted on the peripheral frame (11) to be stretched and allowing the cloth (12) to vibrate. main character:

Description

REFERENCE TO THE RELATED PATENT APPLICATIONS

The present application claims priority to Italian utility model no. 102021000008651 , the contents of which are incorporated by reference.

SECTOR OF TECHNOLOGY

The present invention relates to an air intake system for driving a vehicle.

The present invention finds advantageous application to an aircraft (or man-made machine capable of staying aloft and moving in the air, thus permitting the transportation of people or things within the earth's atmosphere), and more particularly to a helicopter to which the following treatise explicitly refers to without losing its general validity.

PREVIOUS PRIOR ART

A helicopter is equipped with at least one engine that operates a set of wings that allow the helicopter to climb and descend vertically, stand still in flight, move sideways, backward, or forward. An air intake system is provided, which sucks in the air necessary for the functioning of the drive (or the outside air containing the oxygen necessary for combustion). The intake system includes at least one air intake and an intake duct connecting the air intake to the engine. The intake system could also include an air filter placed along the intake duct (generally near or on the air intake) with the function of filtering the intake air to retain small sized impurities (dust or similar) that accumulate over time can lead to premature wear of the drive.

The patent applications EP3655637A1 , EP3536932A1 , EP3392144A1 , EP3601057A1 , EP3091211 , EP3121414 and EP3121415 provide some examples of helicopters where the induction system includes an air cleaner.

During take-off or landing maneuvers in very dusty places (e.g. in desert areas and especially outside of airports or heliports where maneuvering is possible in relatively clean environments), the air filter can become clogged due to the large amount of dust (or sand) that accumulates suspended in the intake air, clogs rapidly both from the natural action of the wind and from the action of the air vortices created by the helicopter wings. The clogging of the air filter due to the large amount of dust (sand) deposited on the outer surface of the air filter forces opening of the branch duct, which supplies the drive with unfiltered and therefore very dusty (sandy) air, thus increasing (or reducing) drive wear nullifies the benefit of the air filter). Also, due to the large amount of dust (sand) that accumulates on the outer surface of the air filter, air filter clogging can generally only be solved by manual cleaning once the helicopter is stationary on the ground, increasing the frequency (and therefore the overall cost) of the cleaning interventions of the air filter considerably.

The patent US2779433A describes an air filter for an aircraft that is adapted to be installed on a component that vibrates in use.

The patent US1757834A describes an air filter in which a suspended and tubular filter element is held taut by a weight attached to the lower end of the filter element.

The patent application WO2007090011A2 describes an air filter for a helicopter comprising a perimeter frame of rectangular shape and a corrugated filter material supported by the perimeter frame.

DESCRIPTION OF THE INVENTION

The aim of the present invention is to provide an air intake system for a vehicle propulsion system which makes it possible to eliminate (or at least significantly reduce) the risk of clogging of the air filter when the vehicle is used in very dusty areas, which is at the same time simple and economical to manufacture.

According to the present invention there is provided an air induction system for a vehicle powertrain as claimed in the appended claims.

The claims describe the preferred embodiments of the present invention and are an integral part of the present description.

character list

• • 1 eine schematische Ansicht eines Hubschraubers ist;
• • 2 eine schematische Ansicht und eine Querschnittsansicht des Hubschraubers aus 1 ist, bei dem ein Antrieb und ein Luftansaugsystem gemäß der vorliegenden Erfindung hervorgehoben sind;
• • 3 eine schematische Ansicht eines Ansaugkanals des Ansaugsystems aus 2 ist;
• • 4 eine Querschnittsansicht eines Hauptluftfilters des Ansaugsystems aus 2 ist;
• • 5 eine schematische und perspektivische Ansicht eines Nebenluftfilters des Ansaugsystems aus 2 ist;
• • 6 eine schematische und perspektivische Explosionsansicht des Nebenluftfilters aus 4 ist;

The present invention will now be described with reference to the accompanying drawings, which show a non-limiting example of its implementation, in which:

• • 1 Figure 12 is a schematic view of a helicopter;
• • 2 Figure 12 shows a schematic view and a cross-sectional view of the helicopter 1 Fig. 12 highlighting a powertrain and air induction system according to the present invention;
• • 3 a schematic view of an intake port of the intake system 2 is;
• • 4 Figure 12 shows a cross-sectional view of a main air cleaner of the intake system 2 is;
• • 5 a schematic and perspective view of a secondary air filter of the intake system 2 is;
• • 6 a schematic and perspective exploded view of the secondary air filter 4 is;

PREFERRED EMBODIMENTS OF THE INVENTION

In the 1 and 2 number 1 designates in its entirety a helicopter comprising a propulsion system 2 (for example, but not necessarily, with a turbine) which sets in motion a set of wings that allow the helicopter to climb and descend vertically, to stand still in flight, to move sideways, backwards or forwards. In particular, the helicopter 1 comprises a main rotor equipped with wings oriented horizontally and rotated by the engine 2 .

An air intake system 3 is provided, which sucks in the air required for the function of the drive 2 (or the outside air containing the oxygen required for combustion). The air intake system 3 comprises two air intakes 4 located on opposite sides of the helicopter 1 and a pair of twin intake ducts 5 each connecting a respective air intake 4 to the engine 2 .

According to the illustration in 3 the air intake system 3 also includes a pair of main air filters 6, each of which is placed along a respective intake duct 5 near the air inlet 4 and has the function of filtering the intake air to retain small-size impurities (dust or similar) that accumulate over time can lead to premature wear of the drive. In front of each main air filter 6 there could be provided a metal screen with a relatively large mesh (of the order of a centimeter or two), which has a protective function against birds.

According to the illustration in 4 each main air filter 6 comprises a peripheral frame 7 (made of aluminium, plastic or composite material) supporting a panel 8 of pleated (or crinkled, i.e. folded over to form a series of corrugations) filter material (e.g. woven or cotton fleece). or other fibres). In other words, the plate 8 made of filter material is corrugated (or wavy) in order to increase the usable area of the filter material with the same external dimensions. The filter material sheet 8 is sandwiched between two layers of thin mesh metal reinforcement which abut (or sandwich) opposite surfaces of the filter material sheet 8 to give the filter material sheet 8 a stable shape and strength to lend. According to a possible (but absolutely not obligatory) implementation, each main air filter 6 also comprises a (flat) stiffening grid 9 placed internally and having the function of supporting the plate 8 of corrugated filtering material to withstand the pressure stresses due to the intake air without to withstand deformation. The function of the stiffening grid 9 for reinforcement is more important in the case of main air filters 6 with a high surface area.

It is important to note that each main air filter 6 as a plan view can have different shapes (e.g. circular, rectangular, elliptical, triangular, trapezoidal or a combination thereof) depending on the shape of the intake duct 5, or depending on the shape of the environment in which the main air filter 6 is arranged.

Each main air filter 6 (or the filter material sheet 8 of the main air filter 6) is sized to retain particles larger than 10 microns (generally this limit is between 5 and 20 microns). In other words, each main air filter 6 (or the sheet 8 of filter material of the main air filter 6) is sized to only allow particles smaller than 10 microns to pass through (generally this limit is between 5 and 20 microns).

According to the illustration in 3 the air intake system 3 also comprises a pair of secondary air filters 10, each of which is arranged along a respective intake duct 5 in front of the main air filter 6 (or closer to the air inlet 4 in relation to the main air filter 6), so that the intake air comes first the secondary air filter 10 and only then the main air filter 6 crosses. In other words, compared to the main air filter 6 , each secondary air filter 10 represents a pre-filter, since it filters the intake air before the main air filter 6 .

Preferably, the main air filter 6 is placed, along a corresponding intake duct 5, inside the intake duct 5 (in any case close to the air inlet 4), while the secondary air filter 10 is placed at the air inlet 4. The eventual metal grid with relatively large meshes (of the order of one or two centimeters), which has a protective function against birds, is of course placed in front of (further outside) the secondary air filter 10 .

As shown in the 5 and 6 For example, each secondary air filter 10 comprises a peripheral frame 11 and a single cloth 12 mounted on the peripheral frame 11 so that it is stretched (or so that it is stretched like a drum skin) to allow the cloth 12 to vibrate (and therefore behaving exactly like a drum skin). The peripheral frame 11 consists of a frame (made of aluminium, plastic or composite material) which imitates the shape of the intake duct 5 and on which the cloth 12 is fixed in a stretched manner. The cloth 12 is made of polymeric material (e.g. peek or nylon) and can be nonwoven or woven with warp and weft.

For example, in each bleed air filter 10, the cloth 12 is secured to the peripheral frame 11 after a tension of between 80 and 500 Newtons has been applied to the cloth 12. It is important to note that the cloth 12 must be adequately tensioned by the peripheral frame 11 to maximize its tendency to vibrate when stressed. In other words, the fabric 12 must be sufficiently tensioned by the peripheral frame 11 but not over-tensioned by the peripheral frame 11 to allow the fabric 12 to vibrate (as much as possible) when stressed.

Each secondary air filter 10 (or the cloth 12 of the secondary air filter 10) is sized to retain particles larger than 50 microns (generally this limit is between 40 and 60 microns). In other words, each bleed air filter 10 (or the cloth 11 of the bleed air filter 10) is sized to only let through particles less than 50 microns in size (generally this limit is between 40 and 60 microns). By virtue of its nature, each secondary air filter 10 has both high permeability (or low load losses) and high filtering efficiency (well over 50%) with respect to particles larger than 50 microns.

The function of each secondary air filter 10 is to block the larger particles that can cause the main air filter 6 to suddenly become clogged. In contrast to the main air filter 6, the secondary air filter 10 is "self-cleaning", i.e. it is able to independently remove larger particles that settle on the outer surface of the secondary air filter 10 and therefore always remain sufficiently free (or avoid clogging). In particular, the tensioned cloth 12 of each secondary air filter 10 is constantly stressed and therefore caused to vibrate by the vibrations generated when the helicopter 1 is flying. In addition, the stretched cloth 12 of each secondary air filter 10 is constantly hit by the downward air flow generated by the rotor blades of the helicopter 1. The combination of the vibration of the stretched fabric 12 and the downward flow of air generated by the rotor blades of the helicopter 1 allows to achieve a continuous "washing" of the outer surface of the fabric 12, which keeps the outer surface of the fabric 12 reasonably clean (free) receives. In other words, the downward flow of air generated by the helicopter's rotor blades "sweeps away" the dust, which is constantly being "bounced" by the stretched cloth 12, which tends to be thrown away by the action of the vibrations of the helicopter 1 in flight to vibrate.

For this purpose, it is important to note that in each secondary air filter 10, the peripheral frame 11 must be adequately rigid (or hardly elastic) and also fixed to the frame of the helicopter 1 without inserting elastic elements in order to transmit to the cloth 12 all the vibrations of the flying helicopter 1 without filtering (to dampen) these vibrations in any way. Because for the correct "self-cleaning" of the secondary air filter 10, it is necessary for the cloth 12 to constantly vibrate.

Preferably, each secondary air filter 10 is arranged at the air inlet 4 so that an outer surface of the cloth 12 is outside the intake duct 5 and can therefore be fully (i.e., without shields) hit by the downward airflow generated by the rotor blades of the helicopter 1 .

According to another embodiment, the air intake system 3 could comprise a single air intake 4 placed in a central position and thus a single intake duct 5 connecting the air intake 5 to the engine 2 .

The embodiment shown as an example in the figures shown relates to a helicopter 1, but the present invention can be advantageously applied to any type of aircraft or other vehicle.

The forms of implementation described here can be combined with one another without leaving the scope of this property right.

The air intake system 3 described above has numerous advantages.

First of all, in the air intake system 3 described above, the presence of the secondary air filter 10 in each intake duct 5 allows rapid clogging of the main air filter 6 during take-off or landing maneuvers in very dusty places (for example in desert areas and especially outside airports or heliports). which allow maneuvering in relatively clean environments).

In addition, in the air intake system 3 described above, the secondary air filters 10 are “self-cleaning” and therefore do not require frequent cleaning interventions.

The presence of the secondary air filters 10 has a very limited effect on the suction efficiency since, being made up of a single stretched fabric 12, they cause small load losses.

And finally, the air intake system 3 described above has a small increase in cost and, above all, a negligible increase in weight compared to a similar air intake system 3 without secondary air filter 10, since the secondary air filters 10 are particularly light and inexpensive.

Reference List

1

helicopter

2

drive

3

air intake system

4

air intake

5

intake duct

6

main air filter

7

surrounding frame

8th

Filter material plate

9

reinforcement grid

10

secondary air filter

11

surrounding frame

12

Cloth

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• IT 102021000008651 [0001]
• EP 3655637 A1 [0005]
• EP 3536932 A1 [0005]
• EP 3392144 A1 [0005]
• EP 3601057 A1 [0005]
• EP 3091211 [0005]
• EP 3121414 [0005]
• EP 3121415 [0005]
• US 2779433 A [0007]
• US 1757834 A [0008]
• WO 2007090011 A2 [0009]

Claims (15)

Air intake system (3) of a drive (2) of a vehicle (1); the air intake system (3) comprising: at least one air inlet (4); an intake duct (5) capable of connecting the air intake (4) to the engine (2); and a main air filter (6) arranged along the intake passage (5); the air intake system (3) is characterized in that: a secondary air filter (10) is provided, which is arranged along the intake duct (5) in front of the main air filter (6) and at a certain distance from the main air filter (6); the secondary air filter (10) comprises a peripheral frame (11) consisting of a self-contained skirt to be uninterrupted, replicating the shape of the intake duct (5) and rigidly fixed to the intake duct (5); and the secondary air filter (10) comprises a non-corrugated single cloth (12) fixed only at its edge to the peripheral frame (11) to be stretched like a drum skin and allow the cloth (12) to vibrate. Air intake system (3) after claim 1 wherein the cloth (12) is made of polymeric material, preferably peek or nylon. Air intake system (3) after claim 1 or 2 , in which the cloth (12) has a tension between 80 and 500 Newtons. Air intake system (3) after claim 1 , 2 or 3 wherein the secondary air filter (10) is sized to retain particles larger than 40-60 microns, and preferably larger than 50 microns. Air intake system (3) according to one of Claims 1 until 4 , in which the secondary air filter (10) has a filtering efficiency of more than 50% of particles larger than 50 microns. Air intake system (3) according to one of Claims 1 until 5 , in which the secondary air filter (10) is arranged at the air inlet (4) so that an outer surface of the cloth (12) is outside the intake duct (5). Air intake system (3) according to one of Claims 1 until 6 , in which the main air filter (6) comprises a plate (8) of corrugated filter material. Air intake system (3) after claim 7 wherein the main air filter (6) is sized to retain particles larger than 5-20 microns, and preferably larger than 10 microns. Air intake system (3) according to one of Claims 1 until 8th wherein: the bleed air filter (10) is sized to retain particles of a first minimum size; and the main air filter (6) is sized to retain particles of a second size below the first minimum size. Air intake system (3) after claim 9 wherein the first minimum size is between three and six times, preferably five times larger than the second minimum size. Air intake system (3) according to one of Claims 1 until 10 wherein the cloth (12) is tensioned by the peripheral frame (11) to maximize its tendency to vibrate when stressed. Air intake system (3) according to one of Claims 1 until 11 , in which the cloth (12) is attached to the peripheral frame (11) only and exclusively along its outer circumference. Air intake system (3) according to one of Claims 1 until 12 , in which the cloth (12) represents a flat closure of the intake duct (5). Air intake system (3) according to one of Claims 1 until 12 , where the cloth (12) is flat. A helicopter (1) comprising: an engine (2); a rotor provided with horizontally oriented vanes and rotated by the drive (2); and an air intake system (3) provided with: at least one air inlet (4); an intake duct (5) connecting the air inlet (4) to the engine (2), and a main air filter (6) arranged along the intake duct (5); the helicopter (1) is characterized in that: a secondary air filter (10) is provided, which is arranged along the intake duct (5) in front of the main air filter (6) and at a certain distance from the main air filter (6); the secondary air filter (10) comprises a peripheral frame (11) consisting of a self-contained skirt to be uninterrupted, replicating the shape of the intake duct (5) and rigidly fixed to the intake duct (5); the secondary air filter (10) comprises a non-corrugated single cloth (12) which is attached only at its edge to the peripheral frame (11) to like a drum skin being taut and allowing the cloth (12) to vibrate; and the secondary air filter 10 is arranged at the air inlet 4 so that an outer surface of the cloth (12) is outside the intake duct (5) and therefore can be fully hit by a downward air flow generated by the rotor blades.

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