# US 11,993,390 B2 · System and method for air filtration with self-cleaning filter medium for an aircraft engine

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- Number: US 11,993,390 B2
- Document ID: US11993390B2
- Status: Granted
- Kind: B2
- Application number: 18/307,430
- Filed: 2023-04-26
- Published: 2023-08-24
- Granted: 2024-05-28
- Earliest claimed: 2020-06-30
- Assignees: Airbus Helicopters
- Applicants: Airbus Helicopters
- Inventors: Benoit Fayard
- Web page: https://patentgrep.com/patent/US11993390B2

## CPC

- B64D 33/02: of combustion air intakes
- F02C 7/055: with intake grids, screens or guards
- F02C 7/052: with dust-separation devices
- F02C 7/057: Control or regulation (conjointly with fuel supply control F02C9/50, with nozzle area control F02K1/16)
- B64D 2033/0246: {comprising particle separators}
- B64D 2033/0253: {specially adapted for particular type of aircraft}
- F05D 2220/323: for aircraft propulsion, e.g. jet engines
- F05D 2220/329: in helicopters
- F05D 2260/607: Preventing clogging or obstruction of flow paths by dirt, dust, or foreign particles
- F05D 2270/114: by limiting mechanical stresses
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

A method for supplying air to an engine of an aircraft via an air supply system of the aircraft. A dynamic air intake vent of the system can be closed by a closure member that is movable between a closed position and an open position. A static air intake vent is equipped with a filter medium. During flight, the method comprises an unfiltered operating mode that comprises the following steps: positioning of the closure member in the open position, and, during a phase of forward travel of the aircraft, dynamic intake of a flow of air, then transfer of a first portion of the flow of air to the engine and a second portion of the flow of air to the filter medium in order to clean the filter medium.

## Claims

### Claim 1

A method for supplying air to an engine of an aircraft at an air supply flow rate via an air supply system of the aircraft during a phase of forward travel of the aircraft, the air supply system comprising a dynamic air intake vent that can be closed by a closure member, the closure member being movable between a closed position in which the closure member closes the dynamic air intake vent and an open position in which the closure member does not close the dynamic air intake vent, the air supply system further comprising a static air intake vent equipped with a filtration device having a filter medium, the method comprising:
responsive to the aircraft flying over a desert area, positioning the closure member in the closed position to implement a filtered operating mode during which air from an external environment situated outside the aircraft is taken in through the static air intake vent, filtered by the filter medium, and supplied to the engine at the air supply flow rate;
responsive to the aircraft flying over a non-desert area, positioning the closure member in the open position to implement an unfiltered operating mode during which a flow of air from the external environment is taken in through the dynamic air intake vent at an air intake flow rate higher than a minimum flow rate necessary in order to obtain the air supply flow rate as a result of the forward travel of the aircraft with a first portion of the flow of air being supplied to the engine and a second portion of the flow of air being supplied to the filter medium, the second portion of the flow of air passing through the filter medium to return to the external environment in order to clean the filter medium; and
positioning the closure member in the closed position to implement the filtered operating mode whenever a pollution in the air of the external environment is greater than a pollution threshold regardless of whether the aircraft is flying over the non-desert area.

### Claim 2 (depends on 1)

The method of claim 1 further comprising,
detecting whether the aircraft is flying over a desert area or a non-desert area by combining a current geographical position of the aircraft with a stored map.

### Claim 3 (depends on 2)

The method of claim 2 further comprising,
obtaining the current geographical position of the aircraft by obtaining a latitude and a longitude of the aircraft.

### Claim 4 (depends on 1)

The method according to claim 1 further comprising:
positioning the closure member in the closed position to implement the filtered operating mode whenever a clogging level of the filter medium is lower than a clogging threshold regardless of whether the aircraft is flying over the non-desert area.

### Claim 5

An air supply system for supplying air to an engine of an aircraft at an air supply flow rate during a flight of the aircraft, the air supply system comprising:
a dynamic air intake vent that can be closed by a closure member, the closure member being movable between a closed position in which the closure member closes the dynamic air intake vent and an open position in which the closure member does not close the dynamic air intake vent;
a static air intake vent equipped with a filtration device having a filter medium;
a controller operable to move the closure member between the closed and open positions;
a pollution sensor configured to detect for a pollution in the air of an external environment;
a clogging sensor configured to detect for a clogging of the filter medium; and
wherein the controller, responsive to the aircraft flying over a desert area, moves the closure member to the closed position to implement a filtered operating mode during which air from the external environment situated outside the aircraft is taken in through the static air intake vent, filtered by the filter medium, and supplied to the engine at the air supply flow rate;
the controller, responsive to the aircraft flying over a non-desert area and during a phase of forward travel of the aircraft, moves the closure member to the open position to implement an unfiltered operating mode during which a flow of air from the external environment is taken in through the dynamic air intake vent at an air intake flow rate higher than a minimum flow rate necessary in order to obtain the air supply flow rate as a result of the forward travel of the aircraft with a first portion of the flow of air being supplied to the engine and a second portion of the flow of air being supplied to the filter medium, the second portion of the flow of air passing through the filter medium to return to the external environment in order to clean the filter medium; and
the controller implements the filtered operating mode whenever the pollution is greater than a pollution threshold regardless of whether the aircraft is flying over the non-desert area.

### Claim 6 (depends on 5)

The air supply system according to claim 5,
wherein the air supply system further comprises an actuation device equipped with an actuator cooperating with the movable closure member, the actuator being configured to move the movable closure member between the open position and the closed position.

### Claim 7 (depends on 6)

The air supply system according to claim 6,
wherein the air supply system further comprises at least one control that can be activated by a pilot, the at least one control being connected via a wired or wireless link to the actuation device.

### Claim 8 (depends on 6)

The air supply system according to claim 6,
wherein the air supply system further comprises a positioning sensor configured to emit a positioning signal transmitted via a wired or wireless link to the actuation device, the positioning signal carrying information indicating a geographical position of the aircraft.

### Claim 9 (depends on 5)

An aircraft equipped with at least one engine,
wherein the aircraft comprises the air supply system according to claim 5 for conveying air present in an external environment situated outside the aircraft towards the engine.

### Claim 10 (depends on 5)

The air supply system according to claim 5 wherein:
the controller implements the filtered operating mode whenever the clogging is lower than a clogging threshold regardless of whether the aircraft is flying over the non-desert area.