WO2014030024A1

WO2014030024A1 - Pre-cooler system with bypass valve, controller therefor, method and aircraft using the same

Info

Publication number: WO2014030024A1
Application number: PCT/IB2012/001623
Authority: WO
Inventors: Jonathan LUSSIER
Original assignee: Bombardier Inc.; Short Brothers Plc
Priority date: 2012-08-22
Filing date: 2012-08-22
Publication date: 2014-02-27

Abstract

The present disclosure relates to a pre-cooler system comprising a pre-cooler (112) for cooling hot bleed air from an engine, and a bypass valve (204) for diverting at least a portion of the hot bleed air to bypass the pre-cooler (112). The present disclosure further relates to a controller having an input for receiving from a sensor at least one of a pressure measurement or a temperature measurement of pre-cooled bleed air at a bleed air output port of the pre-cooler (112), an output connected to the bypass valve (204), and a processor for comparing the at least one of the pressure measurement and the temperature measurement with predetermined values for controlling operation of the bypass valve. The present disclosure also relates to an aircraft including the present pre-cooler system, and to a method for controlling bleed air pressure in a pre-cooler system.

Description

PRE-COOLER SYSTEM WITH BYPASS VALVE, CONTROLLER THEREFOR, METHOD AND AIRCRAFT USING THE SAME

TECHNICAL FIELD

[0001] The present disclosure relates to the field of aircraft engines.

More specifically, the present disclosure relates to a pre-cooler system with a bypass valve, to a controller of the pre-cooler system and to a method and an aircraft using the present pre-cooler system.

BACKGROUND

[0002] It is known to bleed hot, compressed air generated by an aircraft engine and provide that compressed air to equipment on the aircraft to perform certain onboard functions.

[0003] Specifically, it is known to extract hot, compressed air, known as "bleed air" to those skilled in the art, from an aircraft engine so that the hot air may be used for various aircraft functions, including aircraft functions outside of the aircraft engine. For example, bleed air may be used in an aircraft's heating, ventilation, and air conditioning (HVAC) system. Other use of bleed air may also include aircraft's anti-icing system and by aircraft's fuel tank inerting system.

[0004] For an HVAC system installed in an aircraft with two engines, bleed air typically is extracted from each engine and is sent to respective left and right side HVAC packs. The bleed air may be used to condition recirculated air in the cockpit and passenger cabin, where the bleed air conditions (i.e., heats) the cabin temperature and pressurizes the aircraft's interior.

[0005] For the wing anti-icing (WAI) system, the hot bleed air may be used to heat areas of the aircraft which are prone to ice accumulation, such as along a wing's leading edge. [0006] Depending upon the location where the bleed air is removed from an engine, the bleed air may exit the engine at temperatures up to 450°C or more. Specifically, bleed air taken from a location near to the low pressure (LP) turbine may be at a temperature of about 120°C. Bleed air from a location near to the high pressure (HP) turbine may be at a temperature of about 500°C. Since the temperature of the bleed air may be too hot to directly circulate within the various systems of the aircraft, the hot bleed air may have to be cooled prior to use with one or more of the aircraft's other systems. As a result, it is known to provide a cooling device, commonly referred to as a pre- cooler (PCE), to cool the hot bleed air down to a temperature between about 200°C to 232°C depending on the usage. It is known as well that the PCE introduces a pressure drop to the bleed air that passes therethrough.

[0007] A pre-cooler typically utilizes outside (or ambient), that is, air drawn into by a fan to cool the hot, bleed air. The ambient air may be between 50°C, at low altitude on a hot day, and -55°C, at high altitude on a cold day. The pre-cooler typically includes a cross flow air-to-air heat exchanger that transfers heat energy from streams of the hot, bleed air to the stream of cold, ambient air, while the two streams remain separated from one another. As should be apparent to those skilled in the art, a stream of cooled, bleed air exits from the pre-cooler for use within the aircraft. Consequently, a stream of heated, ambient air also exits from the pre-cooler.

[0008] For example, Figure 1 is a block diagram of a conventional pre-cooler system. A pre-cooler system 100 comprises a HP port 102 and a LP port 104, respectively connected to HP and LP stages of an aircraft engine, for example a turbofan (not shown). Bleed air extracted through the HP port 02 and the LP port 104 is fed, respectively, to a high pressure valve (HPV) 106 and to an injection pressure control valve (IPCV) 108. Outputs from both the HPV 106 and the IPCV 108 then enter a pressure regulating shut-off valve (PRSOV) 110 before reaching a pre-cooler (PCE) 112. The PCE 112 comprises four (4) ports, including a hot air entry port 114 connected to the

3383883.1 PRSOV 110, a cold air entry port 1 16 connected to a fan air valve (FAV) 1 18 further connected to a fan air source 120 (not shown in Figure 1), a cold air output port 122 for expelling cold air, and a hot air output port 124 to provide controlled temperature bleed air 126 to bleed air users (not shown).

[0009] Conventionally, bleed air is obtained from the LP port 104 when the engine is at high speed, for example while the aircraft is climbing after take-off, or from the HP port 102 when the engine is at low RPM, for example during aircraft descent/cruise or idle. The bleed air passes through the PCE 112 and a temperature of the bleed air 126 at the hot air output port 124 is controlled by an amount of ambient air introduced into the cold air input port 116 by the FAV 118.

[0010] Bleed air use and pre-coolers are known in the art. Examples of known uses of bleed air and of known pre-coolers are described in the following references:

[0011] U.S. Patent No. 2,969,653,

[0012] U.S. Patent No. 3,537,510,

[0013] U.S. Patent No. 3,981 ,466,

[0014] U.S. Patent No. 4,765,131 ,

[0015] U.S. Patent No. 4,802,621 ,

[0016] U.S. Patent No. 5,063,963,

[0017] U.S. Patent No. 5,125,597,

[0018] U.S. Patent No. 5, 137,230,

[0019] U.S. Patent No. 5, 161 ,364,

[0020] U.S. Patent No. 6,629,428,

[0021] U.S. Patent No. 6,796,131 ,

[0022] U.S. Patent Application Publication No. 2008/0230651 ,

[0023] U.S. Patent Application Publication No. 2009/0107657,

3383883.1 and

[0024] U.S. Patent Application Publication No. 2009/0301 110.

[0025] A brief discussion of these references is provided below.

[0026] U.S. Patent No. 2,969,653 to Trowbridge et al. describes an auxiliary power system for use in an aircraft. An auxiliary turbine is driven by bleed air.

[0027] U.S. Patent No. 3,537,510 to Rannenberg ef al. describes controlling a load on a pre-cooler using a pressure-regulating valve.

[0028] U.S. Patent No. 3,981 ,466 to Shah describes an anti-icing and environmental control system using bleed air from a gas turbine.

[0029] U.S. Patent No. 4,765,131 to Benson describes using pressure regulating valves for balancing aircraft engine bleed air flow.

[0030] U.S. Patent No. 4,802,621 to Standke describes a thermal modulating control valve for providing bleed air for aircraft anti-icing purposes.

[0031] U.S. Patent No. 5,063,963 to Smith describes bleed air systems. Three bleed ports are connected to a bleed air output connector through an assortment of valves.

[0032] U.S. Patent No. 5, 125,597 to Coffinberry describes cooling bleed air for powering an environmental control system.

[0033] U.S. Patent No. 5, 137,230 to Coffinberry describes an environmental control system using bleed air. Unused energy is recovered by pumping boundary layer air from the surface of the aircraft and exhausting this air rearward of the engine to produce thrust.

[0034] U.S. Patent No. 5, 161 ,364 to Bruun et al. describes mixing bleed air from high and low pressure compressor stages of a gas turbine using a proportional valve.

[0035] U.S. Patent No. 6,629,428 to Murry describes an

3383883.1 environmental control system using electric motor driven compressors instead of engine bleed air.

[0036] U.S. Patent No. 6,796,131 to Sampson describes an environmental control system using a mode valve allowing input of ambient air during ground operation of an aircraft.

[0037] U.S. Patent Application Publication No. 2008/0230651 to Porte describes a pre-cooler for use with a turbofan. Heated cool air is evacuated through a discharge pipe connected to the pre-cooler.

[0038] U.S. Patent Application Publication No. 2009/0107657 to

Montminy et al. describes a cooling system for airplane electronics, for ground service. A sub-cooler may be turned on or off.

[0039] U.S. Patent Application Publication No. 2009/03011 10 to

Klimpel describes an air-conditioning system for aircraft, using a bleed air source. A main valve controls a mass air flow from the bleed air source.

[0040] Aircraft functions impose high bleed air requirements from engines bleed air ports. Traditional large core aircraft engines could supply bleed air in relatively large amounts. However, new high bypass ratio engines may have limited available bleed air supply under certain operating conditions, in certain portions of a flight, at least partially due to the smaller size of their cores compared to older/conventional engine designs. Under maximum bleed air flow conditions, such as when a large pressure drop is present through the pre-cooler. The loss of bleed air pressure might be as high as 10 pounds per square inch (PSI). In low power modes, for example during flight descent or holding, the pressure loss in the pre-cooler may impact the overall performance of the bleed air users. As higher bypass ratio engines with smaller cores become prevalent, there is a need for more efficient way of pre- cooling of bleed air.

[0041] Therefore, there is a need for a pre-cooler system that allows efficient supply of bleed air under most aircraft operating conditions.

3383883.1 SUMMARY

[0042] According to the present disclosure, there is provided a pre- cooler system comprising a pre-cooler and a bypass valve. The pre-cooler cools hot bleed air from an engine. The bypass valve diverts at least a portion of the hot bleed air to bypass the pre-cooler.

[0043] In a particular aspect, the bypass valve is configured to allow a portion of the hot bleed air to pass through the pre-cooler for producing cooled bleed air and to allow another portion of the hot bleed air to bypass the pre- cooler.

[0044] In another particular aspect, the pre-cooler system further comprises a controller configured to perform at least one of: detect when the bypass valve is to be actuated, adjust a flow of hot bleed air diverted from the pre-cooler, detect when the bypass valve is to be deactivated.

[0045] In yet another particular aspect, the pre-cooler system further comprises a pressure regulating shut-off valve for feeding/controlling the hot bleed air fed to the pre-cooler, and wherein the bypass valve is configured for diverting the hot bleed air upstream of the pressure regulating shut-off valve.

[0046] In another aspect, the pre-cooler system further comprises a pressure regulating shut-off valve for feeding/controlling the hot bleed air fed to the pre-cooler, wherein the bypass valve is configured for diverting the hot bleed air downstream of the pressure regulating shut-off valve.

[0047] In yet another aspect, the pre-cooler system further comprises a fan air valve for controlling an amount of cold ambient air fed into the pre- cooler.

[0048] In still another aspect, the pre-cooler system further is provided with a junction point for combining pre-cooled hot bleed air with the hot bleed air diverted from the pre-cooler.

[0049] In yet another aspect, the pre-cooler system further comprises

3383883.1 at least one sensor for measuring at least one of a pressure or temperature of the hot bleed air upstream of the pre-cooler.

[0050] According to the present disclosure, there is also provided a controller of a pre-cooler system. The controller comprises an input, an output and a processor. The input receives from a sensor at least one of a pressure measurement and a temperature measurement of pre-cooled bleed air at a bleed air output port of the pre-cooler. The output is connected to the bypass valve. The processor compares the at least one of the pressure measurement and the temperature measurement with predetermined values and controls operation of the bypass valve based on the comparison there between.

[0051] According to the present disclosure, there is also provided an aircraft, comprising an engine, equipment using temperature controlled bleed air, and a pre-cooler system. The pre-cooler system comprises a pre-cooler for cooling hot bleed air from the engine, a sensor for detecting a condition, a bypass valve for diverting at least some of the hot bleed air from the pre- cooler, and a controller for controlling the bypass valve, as a function of the condition.

[0052] In a particular aspect, the condition is at least one of: a pressure of pre-cooled bleed air, aircraft in descent, aircraft in cruise and aircraft in approach.

[0053] In another particular aspect, the equipment using temperature controlled bleed air is selected from a group consisting of: heating, ventilation, air conditioning, pressurization, wing anti-icing system and fuel tank inerting system.

[0054] In yet another aspect, the present disclosure relates to a method for controlling at least one of bleed air pressure and bleed air temperature in a pre-cooler system. The method comprises detecting a condition, actuating a bypass valve for diverting at least a portion of the hot bleed air from a pre-cooler, and providing the diverted hot bleed air to bleed air

3383883.1 users.

[0055] In another aspect, the bypass valve is configured for diverting the hot bleed air upstream of a pressure regulating shut-off valve of the pre- cooler system.

[0056] In another aspect, the bypass valve is configured for diverting the hot bleed air downstream of a pressure regulating shut-off valve of the pre- cooler system.

[0057] In yet another particular aspect, the method further comprises receiving from a sensor at least one of a pressure measurement and a temperature measurement of pre-cooled bleed air at a bleed air output port of the pre-cooler system; comparing the at least one measurement with at least one predetermined value; and controlling operation of the bypass valve based on the comparison there between.

[0058] In yet another particular aspect, the condition is any of the following: a pressure at an output of pre-cooled bleed air, aircraft in descent, aircraft in cruise, and aircraft in approach.

[0059] In still another particular aspect, the method further comprises combining the diverted hot bleed air with pre-cooled bleed air before providing the diverted hot bleed air and the pre-cooled bleed air to bleed air users.

[0060] In yet another particular aspect, the present method further comprises measuring at least one of a pressure or temperature of the hot bleed air upstream of the pre-cooler.

[0061] The foregoing and other features will become more apparent upon reading of the following non-restrictive description of illustrative embodiments thereof, given by way of example only with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Embodiments of the disclosure will be described by way of

3383883.1 example only with reference to the accompanying drawings, in which:

[0063] Figure 1 is a block diagram of a conventional pre-cooler system;

[0064] Figure 2 is a block diagram of a pre-cooler system in accordance with an embodiment;

[0065] Figure 3 is a block diagram of a pre-cooler system according to another embodiment;

[0066] Figure 4 is a block diagram of a pre-cooler system according to yet another embodiment;

[0067] Figure 5 is a block diagram of a pre-cooler system according to another embodiment;

[0068] Figure 6 is a block diagram of an example controller for use with the various embodiments of the pre-cooler system;

[0069] Figure 7 is a schematic diagram of an aircraft equipped with one the various embodiments of the pre-cooler system; and

[0070] Figure 8 is a schematic representation of a method for controlling bleed air pressure in a pre-cooler system.

DETAILED DESCRIPTION

[0071] Like numerals represent like features on the various drawings.

[0072] Various aspects of the present disclosure generally address one or more of the problems related to bleed air from aircraft engines, for example from high bypass ratio engines. The present disclosure thus relates to aircraft engine pre-cooler systems and to efficiency improvements thereof. Disclosed system and its numerous variants allow reducing pressure loss in precooling of bleed air. In particular, the present disclosure encompasses a

3383883.1 precooling system providing temporarily precooling bypass for bleed air in an aircraft.

[0073] The following acronyms are used throughout the present disclosure:

[0074] FAV: fan air valve.

[0075] HP: high pressure.

[0076] HPV: high pressure valve.

[0077] HVAC: heating, ventilation, and air conditioning

[0078] IPCV: Intermediate (low) pressure check valve.

[0079] LP: low pressure.

[0080] PBV: bypass valve.

[0081] PCE: pre-cooler.

[0082] PRSOV: pressure regulating shut-off valve.

[0083] PSI: pound per square inch.

[0084] RPM: revolutions per minute.

[0085] WAI: wing anti-ice.

[0086] In a particular aspect, the present disclosure introduces a pre- cooler system using a pre-cooler (PCE) bypass valve (PBV). The PCE is used for cooling hot bleed air extracted from an engine. The PBV allows diverting, at least in part, the hot bleed air so as to bypass the pre-cooler. The PBV may be activated when the aircraft's engines provide low power outputs, for example during descent or holding and while bleed air temperature is maintained below a regulation setting.

[0087] In certain aspects, the pre-cooler system may provide bleed air consisting of a majority of the bleed air passing through the PBV, with a small percentage of the bleed air passing through the PCE in order to regulate an overall bleed air output temperature.

3383883.1 [0088] In some variations of the pre-cooler system, the PCE may obtain ambient air in an amount controlled by a fan air valve (FAV). In other variations, depending on characteristics of the engines and on pressure and temperature requirements for the bleed air, the FAV might not be necessary.

[0089] Previously discussed pre-cooler systems include variations where the PBV may be connected upstream or downstream of a pressure regulating shut-off valve (PRSOV), which combines both high pressure (HP) and low pressure (LP) bleed air engine outputs.

[0090] The PCE bleed air cooling function may be generally relied on in high pressure supply situations. In low pressure situations, temperature available at the aircraft engine bleed air ports may be at or near adequate levels for the bleed air users of the aircraft. Actuation of the PBV and bypassing at least in part the PCE reduces bleed air pressure drop. In these situations, bleed air from the engines' LP ports may be used, further reducing bleed air temperature and reducing engine fuel consumption.

[0091] Referring now to the drawings, Figure 2 is a block diagram of a pre-cooler system 200 using a bypass valve according to a first embodiment. The pre-cooler system 200 comprises a HP port 102 and a LP port 104, respectively connected to HP and LP stages of an aircraft engine, for example a turbofan (not shown). Bleed air extracted through the HP port 102 and the LP port 104 is fed, respectively, to a high pressure valve (HPV) 106 and to an Intermediate (Low) Pressure Check valve (IPCV) 108. Outputs from both the HPV 106 and the IPCV 108 may be directed over two distinct paths. Over a first path, a portion or all of the outputs from the HPV 106 and from the IPCV 108 may enter a PRSOV 110 before reaching a PCE 1 12.

[0092] The PCE 1 2 comprises four (4) ports, including a hot bleed air entry port 114 connected to the PRSOV 110, a cold ambient air entry port 116, an ambient air output port 122 for expelling ambient air having passed in the pre-cooler, and a bleed air output port 124 to provide pre-cooled bleed air 202.

3383883.1 [0093] Another portion of the outputs from the HPV 106 and from the

IPCV 108 may be diverted from the PCE 112, directed over a second path to a PBV 204, which is connected upstream of the PRSOV 1 0, at point 210, and forwarded, uncooled, as hot bleed air 206. The pre-cooled bleed air 202 and the hot bleed air 206 may be blended at a junction point 208 to provide a controlled temperature bleed air 126 to bleed users (not shown). The junction point 208 may be implemented as a simple manifold joining outputs of the PCE 1 12 and of the PBV 204. The junction point 208 may be implemented in any other suitable manner envisioned by those of ordinary skill in the art.

[0094] The PBV 204 may be controlled to block or to allow at least a portion of the outputs from the HPV 106 and from the IPCV 108 to pass therethrough. In particular, the PBV 204 may be controlled in terms of pressure and in terms of flow. The PBV 204 may control the pressure of the bleed air 126 provided to the bleed users.

[0095] Figure 3 is a block diagram of a pre-cooler system 300 according to another embodiment. In contrast with the system 200 of Figure 2, the cold ambient air entry port 1 16 is connected to a fan air source via a FAV 118. Pre-cooled bleed air 202 is expelled from the bleed air output port 124.

[0096] Temperature of the pre-cooled bleed air 202 at the hot output port 124 is controlled by an amount of ambient air allowed into the cold ambient air input port 1 6 by the FAV 1 8 and PBV position. When the PBV 204 is fully closed, the FAV 118 controls the amount of ambient air so that the pre-cooled bleed air 202 meets a desired temperature set point for the controlled temperature bleed air 126. The PBV 204 may be controlled to block or to allow at least a portion of the outputs from the HPV 106 and from the IPCV 08 to pass therethrough. In particular, the PBV 204 may be controlled in terms of pressure and in terms of flow. The PBV 204 may open in case of low bleed air pressure, in which case at least a part of the outputs from the HPV 106 and from the IPCV 108 may bypass the PRSOV 110 and the PCE 112. Temperature of the bleed air 126 obtained from the combination of the hot

3383883.1 bleed air 206 having by-passed the pre-cooler, with the pre-cooled bleed air 202 may be controlled jointly by the PBV 204 and by the FAV 118.

[0097] Figure 4 is a block diagram of a pre-cooler system 400 according to another embodiment. In the present embodiment, bleed air extracted through the HP port 102 and the LP port 104 is fed, respectively, to the HPV 106 and to the IPCV 108. Outputs from both the HPV 106 and the IPCV 108 then enter the PRSOV 110. Output from the PRSOV 110 may then proceed to the hot bleed air input port 114 of the PC 112. Alternatively, the output from the PRSOV 110 may proceed to the PBV 204, which is connected downstream of the PRSOV 110. Bleed air from the PRSOV 110 may be split in variable portions between the PCE 112 and the PBV 204, or may be fully diverted from the pre-cooler 112. For example, in a particular operating mode of the system 400, most of the bleed air passes through the PCE 112 and a smaller portion of the bleed air is diverted by the PBV 204 and proceeds therethrough as hot bleed air 206. Pre-cooled bleed air 202 is expelled from the hot bleed air output port 124 and is blended with the hot bleed air 206 at the mixer 208 to provide the controlled temperature bleed air 126 to bleed users.

[0098] Figure 5 is a block diagram of a pre-cooler system 500 according to yet another embodiment, which is a variant of the pre-cooler system 400 of Figure 4. In the present variant, the cold ambient air entry port 116 is connected to the fan air source 120 via the FAV 118. Pre-cooled bleed air 202 is expelled from the hot bleed air output port 124 and is blended with the hot bleed air 206 having bypassed the pre-cooler at the mixer 208, to provide the controlled temperature bleed air 126 to bleed users.

[0099] A temperature of the pre-cooled bleed air 202 at the hot bleed air output port 124 is controlled by an amount of ambient air allowed into the cold ambient air input port 116 by the FAV 118. When the PBV 204 is fully closed, the FAV 118 controls the amount of ambient air so that the cooled bleed air 202 meets a desired temperature set point for the controlled

3383883.1 temperature bleed air 126. The PBV 204 may be controlled to block or to allow at least a portion of the output from the PRSOV 110 to pass therethrough. In particular, the PBV 204 may be controlled in terms of pressure and in terms of flow. The PBV 204 may open in case of low bleed pressure, in which case at least a part of the outputs from the PRSOV 10 may bypass the PCE 112. A temperature of the bleed air 26 obtained from a combination of the hot bleed air 206 with the pre-cooled bleed air 202 may be controlled jointly by the PBV 204 and by the FAV 118.

[00100] Figure 6 is a block diagram of an example controller for use with the various embodiments of the pre-cooler system. A controller 600 comprises a processor 602, a memory 604, an input 606 and an output 608.

[00101] The input 606, which may be implemented as a single port or as multiple ports, is connected to one or more of the following sensors:

[00102] a sensor 104s for measuring current pressure and/or temperature at the LP port 04,

[00103] a sensor 102s for measuring current pressure and/or temperature at the HP port 102,

[00104] a sensor 114s for measuring current pressure and/or temperature at the hot bleed air entry port 114,

[00105] a sensor 116s for measuring current pressure and/or temperature at the cold ambient air entry port 116,

[00106] a sensor 210s for measuring current pressure and/or temperature at the input of the PRSOV 110, shown as point 2 0 on earlier Figures,

[00107] a sensor 202s for measuring current pressure

temperature of the pre-cooled bleed air 202,

[00108] a sensor 206s for measuring current pressure and/or temperature of the hot bleed air 206, and

3383883.1 [00109] a sensor 126s for measuring current pressure and/or temperature of the controlled temperature bleed air 126.

[00110] Some of the above mentioned sensors may not be present in various embodiments and some of the sensors may only provide a temperature reading, or a pressure reading, as required by the processes implemented in the processor 602.

[00111] The output 608, which may be implemented as a single port or as multiple ports, is connected to one or more of the following valves: the HPV 106, the PRSOV 110, the FAV 118, and the PBV 204.

[00112] The memory 604 may store a desired temperature range and/or a require pressure for the bleed air 126 outputted by the pre-cooling system. The memory 604 may also store set points for control of the various valves of the pre-cooler system. The set points are made available to the processor 602 by the memory 604.

[00113] The processor 602 receives measurements from the various sensors and executes processes of the controller 600 for controlling the pre- cooler system. The controller 600 may control full or partial opening or closing of the HPV 106, PRSOV 110, FAV 118 and PBV 204.

[00114] In particular, the processor 602 may detect, via the sensor

126s, a current temperature and/or pressure of the bleed air 126. Based at least on the measurement received from the sensor 126s, the processor 602 controls operation of the PBV 204, and may further control operation of the PRSOV 110, or both, in order to allow an efficient blend of the hot bleed air 206 with the pre-cooled bleed air 202, for controlling the pressure and temperature of the bleed air 126 according to the desired set point. Opening and closing of the PRSOV 110 to control an amount of hot bleed air entering therethrough may additionally be determined in part based on a current temperature and/or pressure of the hot bleed air upstream of the PRSOV 110, at point 210.

3383883.1 [00115] Control of the temperature of the pre-cooled bleed air 126 may be obtained when the controller 600 controls operation of the FAV 118 for admitting ambient air in the pre-cooler based on current temperature and/or pressure readings of the pre-cooled bleed air 202 obtained from the sensor 202s. Control of the FAV 118 by the controller 600 may also rely on current temperature and/or pressure readings of ambient air entering the PCE 1 12 at the cold entry port 116, by the sensor 116s.

[00116] The controller 600 may also control opening and closing of the

HPV 106 in order to extract bleed air from the LP port 104, from the HP port 102, or both, according to engine operating conditions as determined, at least in part, from readings of the sensors 104s and 102s, or from a detected condition identified therefrom. For example, pressure readings at sensors 104s and 102s indicate to the controller a state of an aircraft, for example that the pressure of pre-cooled bleed air; aircraft in descent, aircraft in cruise and aircraft in approach, or any other condition that may be detected by the controller, and affects the pressure of bleed air. Other operations of the controller 600, based on readings from the various sensors and based on set points stored in the memory 604, will readily come to those of ordinary skill in the art having the benefit of the present disclosure. Additionally, the controller 600 may also control opening and closing of the HPV 106 in order to extract bleed air from the LP port 104, from the HP port 102, or both, according to control messages and alert messages received from any system from an avionic suit, such as for example an alert system, a control concentrator, etc.

[00117] Figure 7 is a schematic diagram of an aircraft 700 equipped with one the various embodiments of the pre-cooler system. The aircraft 700 comprises two (2) engines 702 and 704, each of which comprises a LP port 104 and a HP port 102. The aircraft 700 comprises at least one pre-cooler system, for example the pre-cooler system 200. Of course, any of the previously discussed pre-cooler systems 200, 300, 400 or 500 may be mounted on the aircraft 700. The pre-cooler system 200 is controlled by means

3383883.1 of the controller 600. For example, the controller 600 could be added to a standard Air System Controller or a Bleed Air System controller. For safety and reliability reasons, a pair of pre-cooler systems 200 with accompanying controllers 600 may be mounted on the aircraft 700. Temperature controlled bleed air from the pre-cooler system 200 is fed to one or more equipment 706, such as for example a heating, ventilation, and air conditioning (HVAC) system, a wing anti-icing (WAI) system, a fuel tank inerting system.

[00118] Location of the pre-cooler systems 200, controllers 600 and equipment 706 on the aircraft 700, shown on Figure 7, is for illustration purposes and is not intended to limit the present disclosure.

[00119] Reference is now made concurrently to Figures 1 -8, where

Figure 8 is a schematic representation of a method 800 for controlling bleed air pressure with the present pre-cooler system. The method 800 starts with detecting a condition 810. The condition may consist of one particular triggered event, such as for example aircraft in descent, aircraft in hold, aircraft in cruise, aircraft in approach, pressure of the temperature controlled bleed air 126 falling under a predetermined pressure level, etc., or to a combination of conditions related to the pressure of the bleed air being provided to the bleed air users.

[00120] The method 800 pursues with receiving a sensor measurement 820. The sensor measurement may be received from one or several of the following: the LP port sensor 104s, the HP port sensor 102s, the pre-cooler hot bleed air entry port sensor 1 14s, the pre-cooler ambient air input port sensor 1 16s, the temperature controlled bleed air sensor 126s, the PBV sensor 202. The sensor pressure measurement 820 may be at least one of a pressure measurement or a temperature measurement,

[00121] The controller 600 then compares the received sensor measurement(s) with predetermined values stored in memory 604, so as to determine whether the PBV should be actuated so as to allow diverting at least some of the hot bleed air from the pre-cooler 112 to the bleed air users.

3383883.1 [00122] Based on the detected condition and/or the measurement(s) received, the controller 600 further determines the portion of the hot bleed air that should be diverted from the pre-cooler 112 to the bleed air users. The controller 600 then actuates the PBV 204 for diverting the determined portion of the hot bleed air from the pre-cooler 1 12 and providing the diverted hot bleed air either directly or ultimately to the bleed air users.

[00123] When all the hot bleed air is diverted from the pre-cooler 112 by the PBV 204, the diverted hot bleed air is directly provided to the bleed air users.

[00124] When only a portion of the hot bleed air is diverted from the pre-cooler 1 12 by the PBV 204, the diverted bleed air 206 and the pre-cooled bleed air 202 may be combined to form the temperature and pressure controlled bleed air provided to the bleed air users.

[00125] The steps of the present method may be performed sequentially, concurrently, in sub-groups or re-ordered without departing from the scope of the present method.

[00126] Those of ordinary skill in the art will realize that the description of the pre-cooler system, controller, aircraft and method for providing bleed air to bleed users are illustrative only and are not intended to be in any way limiting. Other embodiments will readily suggest themselves to such persons with ordinary skill in the art having the benefit of the present disclosure. Furthermore, the disclosed pre-cooler system, controller and aircraft may be customized to offer valuable solutions to existing needs and problems of controlling bleed air pressure from high bypass ratio engines.

[00127] Although the present disclosure has been described hereinabove by way of non-restrictive, illustrative embodiments thereof, these embodiments may be modified at will within the scope of the appended claims without departing from the spirit and nature of the present disclosure.

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Claims

WHAT IS CLAIMED IS:

1. A pre-cooler system, comprising:

a pre-cooler for cooling hot bleed air from an engine; and a bypass valve for diverting at least a portion of the hot bleed air to bypass the pre-cooler.

2. The pre-cooler system of claim 1 , wherein the bypass valve is configured to allow a portion of the hot bleed air to pass through the pre- cooler for producing cooled bleed air and to allow another portion of the hot bleed air to bypass the pre-cooler.

3. The pre-cooler system of claim 2, further comprising a controller, the controller being configured to perform at least one of: detect when the bypass valve is to be actuated, adjust a flow of hot bleed air diverted from the pre-cooler, detect when the bypass valve is to be deactivated.

4. The pre-cooler system of claim 1 , further comprising:

a pressure regulating shut-off valve for controlling the hot bleed air fed to the pre-cooler;

wherein the bypass valve is configured for diverting the hot bleed air upstream of the pressure regulating shut-off valve.

5. The pre-cooler system of claim 1 , further comprising:

wherein the bypass valve is configured for diverting the hot bleed air downstream of the pressure regulating shut-off valve.

6. The pre-cooler system of claim 1 , comprising a fan air valve for controlling an amount of cold ambient air fed into the pre-cooler.

7. The pre-cooler system of claim 1 , further comprising a junction point for

3383883.1 combining pre-cooled hot bleed air with the hot bleed air diverted from the pre-cooler.

8. The pre-cooler system of claim 1 , further comprising at least one sensor for measuring at least one of a pressure or temperature of the hot bleed air upstream of the pre-cooler.

9. A controller of a pre-cooler system, comprising:

an input for receiving at least one of a pressure measurement and a temperature measurement of pre-cooled bleed air at a bleed air output port of the pre-cooler;

an output connected to a bypass valve; and

a processor for comparing the at least one of the pressure measurement and the temperature measurement with predetermined values and for controlling operation of the bypass valve based on the comparison therebetween.

10. An aircraft, comprising:

an engine;

an equipment using temperature controlled bleed air; and a pre-cooler system, comprising:

a pre-cooler for cooling hot bleed air from the engine;

a sensor for detecting a condition;

a bypass valve for diverting at least some of the hot bleed air from the pre-cooler; and

a controller for controlling the bypass valve, as a function of the condition.

11. The aircraft of claim 10, wherein the condition is at least one of: a pressure of pre-cooled bleed air, aircraft in descent, aircraft in cruise, aircraft in approach.

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12. The aircraft of claim 10, wherein the equipment using temperature controlled bleed air is selected from a group consisting of: heating, ventilation, air conditioning, pressurization, wing anti-icing system and fuel tank inerting system.

13. A method for controlling at least one of bleed air pressure and bleed air temperature in a pre-cooler system, the method comprising:

detecting a condition;

actuating a bypass valve for diverting at least a portion of the hot bleed air from a pre-cooler; and

providing the diverted hot bleed air to bleed air users.

14. The method of claim 13, wherein the bypass valve is configured for diverting the hot bleed air upstream of a pressure regulating shut-off valve of the pre-cooler system.

15. The method of claim 13, wherein the bypass valve is configured for diverting the hot bleed air downstream of a pressure regulating shut-off valve of the pre-cooler system.

16. The method of claim 13, further comprising:

receiving from a sensor at least one of a pressure measurement and a temperature measurement of pre-cooled bleed air at a bleed air output port of the pre-cooler system;

comparing the at least one measurement with at least one predetermined value; and

controlling operation of the bypass valve based on the comparison therebetween.

17. The method of claim 13, wherein the condition is at least one of: a pressure of pre-cooled bleed air; aircraft in descent, aircraft in cruise and aircraft in approach.

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18. The method of claim 13, further comprising combining the diverted hot bleed air with pre-cooled bleed air before providing the diverted hot bleed air and the pre-cooled bleed air to bleed air users.

19. The method of claim 13, further comprising measuring at least one of a pressure and temperature of the hot bleed air upstream of the pre- cooler.

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