Environmental control system for aircraft

Abstract

To provide an environmental control system pack for an aircraft.SOLUTION: An environmental control system pack 20 for an aircraft includes a ram air circuit 40 and a bleed flow circuit 30. The ram air circuit receives air from an atmosphere on an exterior of the aircraft and expels the air through an outlet back into the atmosphere. The bleed flow circuit receives bleed air and cools the air prior to the bleed air being delivered to an interior space. The environmental control system pack uses energy from the bleed air to drive a fan in the ram air circuit. This causes an increase in a compression power of the air in the ram air circuit to increase a thrust of the air exiting the ram air circuit through the outlet.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001]

[0001] The present disclosure relates generally to the field of aircraft, and more particularly to environmental control systems within aircraft. [Background technology]

[0002]

[0002] Many aircraft are equipped with an environmental control system (ECS). The ECS provides temperature-conditioned and / or dehumidified air to the aircraft's interior spaces. The air supplied by the ECS is bleed air received from, for example, the engine compressor of the engine or auxiliary power unit. The ECS also includes a ram air circuit that draws air from outside the aircraft. The ram air is relatively cooler and at a lower pressure than the bleed air. The ram air is used to cool the bleed air in one or more heat exchangers contained within the ram air circuit.

[0003] Bleed air is typically high-pressure air that is too hot to be provided directly to the interior space. For example, the bleed air may exceed 300 degrees Fahrenheit. The ECS diverts a portion of the bleed air to the ram air circuit to cool the air. The cooled air is then mixed with other bleed air to achieve the desired temperature before being provided to the interior space. The ECS also reduces the pressure of the bleed air before it is provided to the interior space.

[0004] A challenge with existing systems is the loss of energy that can occur during the supply of air to the interior space. ECS systems reduce the pressure of the bleed air before supplying it to the interior space. This excess energy, in the form of high pressure, is lost in the air supply process. This energy is not utilized in a productive manner. Existing systems use a throttle valve to reduce the pressure of the bleed air. However, throttle valves are energy inefficient.

[0005] Another problem with existing systems is that the ram air circuit generates a negative force, or drag, on the aircraft. This drag is the result of the air entering the ram air circuit moving at a higher velocity than the air exiting it. Summary of the Invention

[0006]

[0006] One aspect is directed to an environmental control system pack for an aircraft. The environmental control system pack includes a ram air circuit that receives air from the atmosphere outside the aircraft and exhausts the air back into the atmosphere through an outlet. The ram air circuit includes a fan for directing the air toward the outlet. A bleed flow circuit receives bleed air from the aircraft engines and cools the air before it is delivered to the aircraft's interior space. The bleed flow circuit includes a turbine. The turbine is operatively connected to the fan. Energy from the bleed air drives the turbine. The turbine, in turn, drives the fan, increasing the compressibility of the air in the ram air circuit and increasing the thrust of the air exiting the ram air circuit.

[0007]

[0007] In another aspect, a shaft extends between the turbine and the fan and operatively connects the turbine and the fan.

[0008]

[0008] In another aspect, the ram air circuit includes a heat exchanger through which bleed air from the bleed flow circuit travels to reduce the temperature of the bleed air.

[0009]

[0009] In another aspect, a fan is positioned upstream from the heat exchanger along the ram air circuit.

[0010]

[0010] In another aspect, the turbine includes variable nozzle guide vanes to regulate bleed air through the bleed flow circuit to allow a predetermined flow rate over a range of pressures of bleed air received from the engine.

[0011]

[0011] In another aspect, the turbine is configured to drive the fan only when the aircraft is in flight.

[0012] One aspect is directed to an environmental control system pack for an aircraft. The environmental control system pack includes a ram air circuit 40. The ram air circuit 40 includes a duct having an inlet for receiving air from the atmosphere and an outlet through which the air is exhausted back into the atmosphere, a fan for directing the air through the duct, and one or more heat exchangers. A bleed flow circuit includes a duct for directing bleed air to the one or more heat exchangers and to an interior space of the aircraft. The bleed flow circuit includes a turbine. Bleed air from the one or more heat exchangers drives the turbine. The turbine drives the fan to increase thrust produced by the ram air circuit.

[0013]

[0013] In another aspect, the fan is configured to increase the pressure of air in the ram air circuit when the fan is driven by the turbine.

[0014] In another aspect, the bleed flow circuit further comprises a compressor, wherein the one or more heat exchangers comprise a first heat exchanger disposed upstream from the compressor and a second heat exchanger disposed downstream from the compressor and upstream from the turbine.

[0015]

[0015] In another aspect, a bypass valve is positioned along the ram air circuit and configured to direct air away from the fan while the aircraft is in flight.

[0016]

[0016] In another aspect, a bypass valve is positioned along the bleed flow circuit, the bypass valve configured to direct bleed air from the first heat exchanger to the second heat exchanger and bypass a section of the bleed flow circuit.

[0017] In another aspect, bleed air from the first heat exchanger drives a turbine, and the second heat exchanger is located downstream from the turbine.

[0018]

[0018] In another aspect, the control unit is configured to control one or more of the turbine nozzle, the compressor bypass valve, the ram air circuit inlet, the ram air circuit outlet, the ram flow rate, and the bleed air flow rate to minimize fuel consumption of the aircraft.

[0019]

[0019] In another aspect, the ram air circuit includes either a fan positioned downstream from the first heat exchanger and the second heat exchanger, or a fan positioned upstream from the first heat exchanger and the second heat exchanger.

[0020] One aspect is directed to a method of generating thrust on an aircraft, the method including receiving air from outside the aircraft into a ram air circuit, the ram air circuit including a fan and one or more heat exchangers, receiving bleed air from an engine of the aircraft into a bleed flow circuit, directing the bleed air through the one or more heat exchangers to reduce a temperature of the bleed air, directing the bleed air that has passed through the one or more heat exchangers to a turbine to power the turbine, driving a fan in the ram air circuit with the turbine to increase a pressure of the air passing through the ram air circuit, and exhausting the air with the increased pressure from the ram air circuit to generate thrust for the aircraft.

[0021] In another aspect, the method further includes directing the bleed air through both the first heat exchanger and the second heat exchanger before directing the bleed air to the turbine.

[0022]

[0022] In another aspect, the method further includes adjusting a nozzle at the outlet of the ram air circuit to generate thrust for the aircraft.

[0023]

[0023] In another aspect, the method further includes directing the bleed air from the turbine to a second heat exchanger, with the second heat exchanger positioned downstream from the turbine along the bleed flow circuit.

[0024]

[0024] In another aspect, the method further includes directing air through a fan into the first heat exchanger and the second heat exchanger, with the fan positioned upstream from the first heat exchanger and the second heat exchanger along the ram air circuit.

[0025]

[0025] In another aspect, the method further includes directing the air through the first heat exchanger and the second heat exchanger, with the first heat exchanger and the second heat exchanger positioned upstream from the fan along the ram air circuit, before directing the air through the fan.

[0026]

[0026] The above-described features, functions, and advantages can be realized alone in various aspects or can be combined in further multiple aspects, details of which can be confirmed by referring to the following description and accompanying drawings. [Brief explanation of the drawings]

[0027] [Figure 1]

[0027] FIG. 1 is an isometric view of an aircraft with an environmental control system pack. [Figure 2]

[0028] 1 is a schematic diagram of a ram air circuit that receives air from outside the aircraft and exhausts the air back into the environment. [Figure 3]

[0029] FIG. 1 is a schematic diagram of an environmental control system pack having a bleed flow circuit and a ram air circuit. [Figure 4]

[0030] FIG. 1 is a schematic diagram of an environmental control system pack having a bleed flow circuit and a ram air circuit. [Figure 5]

[0031] FIG. 1 is a schematic diagram of an environmental control system pack and a first embodiment of the arrangement of bleed flow circuit and ram air circuit components. [Figure 6]

[0032] FIG. 1 is a schematic diagram of one embodiment of an environmental control system pack having an arrangement of components for a bleed flow circuit and a ram air circuit with a compressor bypass valve. [Figure 7]

[0033] FIG. 1 is a schematic diagram of an embodiment of an environmental control system pack having an arrangement of components for a bleed flow circuit and a ram air circuit with a heat exchanger located downstream from the turbine. [Figure 8]

[0034] FIG. 1 is a schematic diagram of an embodiment of an environmental control system pack having an arrangement of components for a bleed flow circuit and a ram air circuit with a heat exchanger located upstream from a fan. [Figure 9]

[0035] FIG. 9 is a schematic diagram of a control unit that controls the operation of the environmental control system pack. [Figure 10]

[0036] A method of generating thrust in an aircraft using an environmental control system pack. [Figure 11]

[0037] FIG. 1 is a schematic diagram of an environmental control system pack having a fluid flow circuit and a ram air circuit. DETAILED DESCRIPTION OF THE INVENTION

[0028]

[0038] 1 generally illustrates an aircraft 100 including a fuselage 101 and wings 102. One or more engines 106 propel the aircraft 100 during flight. The fuselage 101 includes an interior space 103 configured to hold passengers and / or cargo. The interior space 103 includes a cockpit 104 for seating flight personnel to control the aircraft 100 during flight. In some embodiments, the interior space 103 includes a cabin area 105 configured to accommodate passengers. Additionally or alternatively, the interior space 103 includes a hold configured to store cargo.

[0029]

[0039] The aircraft 100 includes an environmental control system (ECS) that provides temperature-conditioned and / or dehumidified air to the interior space 103. When the aircraft 100 is pressurized, the ECS also provides pressurization to a portion or all of the interior space 103. The ECS includes one or more ECS packs 20, each including a bleed flow circuit 30, that provides air to the interior space 103. In some embodiments, bleed air is supplied from one or more of the engines 106. The bleed air is hot (e.g., greater than 300°F) and high-pressure air extracted from one or more compressors of the engines 106. The ECS pack 20 also includes a ram air circuit 40 for reducing the temperature and / or pressure of the bleed air. The ram air circuit 40 may be located in various locations on the aircraft 100, including underneath the aircraft, such as within a wing-fuselage fairing. Air from the atmosphere flows into the ram air circuit 40 through an inlet 41 and exits through an outlet 42. Airflow through ram air circuit 40 occurs while the aircraft is moving through the air (e.g., in flight and / or during high-speed taxiing). At other times, such as when aircraft 100 is parked and / or taxiing slowly, a fan (not shown in FIG. 1 ) drives airflow through ram air circuit 40.

[0030]

[0040] 2 schematically illustrates the ram air circuit 40, which includes an air duct 47 extending between an inlet 41 and an outlet 42. Air from the atmosphere outside the aircraft 100 enters through the inlet 41, travels through the duct 47, and is exhausted back into the atmosphere at the outlet 42. One or more heat exchangers 43 use the ram air to transfer heat from the bleed air and reduce the temperature of the bleed air before it is supplied to the interior space 103. The ram air circuit 40 also includes a fan 45 that moves the ram air along the duct 47. In some embodiments, the fan 45 includes variable-pitch fan blades.

[0031]

[0041] FIG. 3 is a block diagram of ECS pack 20 including bleed flow circuit 30 and ram air circuit 40. The block diagram includes arrows on the depicted ducts to indicate the direction of airflow. In various embodiments, the airflow path is a duct that directs air from one component to another. Ducts may include various configurations and may refer to different types of passages, channels, or other flow paths that may direct the flow of air. In various other embodiments, the two components may be included within a single module, and the airflow path is an internal channel within the module.

[0032]

[0042] The ECS pack 20 is disposed between the one or more engines 106 that supply bleed air 31 and the interior space 103. Bleed air from the one or more engines 106 flows through a duct 80 to a flow control valve (FCV) 32. The FCV 32 is operable to regulate the flow rate of bleed air into the duct 81. The air passing through the FCV 32 is hot, with some embodiments including temperatures above 300°F. The FCV 32 diverts a portion of the air from the duct 81 to the interior space 103 (via a duct 83, an air mixing valve 33, and ducts 85 and 86 leading to the interior space 103). The FCV 32 directs the remaining portion from the duct 81 through a duct 82 to the ram air circuit 40 to reduce its temperature.

[0033]

[0043] In this embodiment, the ram air circuit 40 includes a first heat exchanger 43a and a second heat exchanger 43b. Other embodiments include fewer or more heat exchangers as needed to condition the bleed air. The duct 82 directs the bleed air to the first heat exchanger 43a. The first heat exchanger 43a extracts some of the heat from the air and outputs cooler air to a duct 84. The temperature of the air in the duct 84 depends on several factors, including the ram air temperature. In some embodiments, the temperature of the bleed air in the duct 84 is between 40°F and 200°F.

[0034]

[0044] Air from duct 84 is directed to air mixing valve 33 and mixed with another portion of the bleed air. A portion of the mixed air is directed to duct 85 for delivery to interior space 103. Another portion of the mixed air is directed to duct 87 and compressor 34. Compressor 34 increases the pressure and temperature of the air. Air from compressor 34 passes through duct 88 to second heat exchanger 43b in ram air circuit 40. Second heat exchanger 43b reduces the temperature of the air. The cooled air from second heat exchanger 43b then travels through duct 89 to turbine 35. In some embodiments, turbine 35 is an expander. At the output of turbine 35, air may be near the freezing point of water (e.g., in the range between 30°F and 35°F), depending on the ram air temperature and the airflow through ram air circuit 40.

[0035]

[0045] Air from turbine 35 in duct 79 is combined with bleed air flowing from duct 85. In some embodiments, a water separator 36 is positioned along duct 86 to remove water from the air. The air reaches interior space 103 via duct 86 at the appropriate temperature, providing controllable temperature regulation within interior space 103.

[0036]

[0046] The bleed air has high pressure when initially received at the ECS pack 20. The ECS pack 20 is configured to convert energy from the excess pressure in the bleed air and generate thrust in the ram air circuit 40 to propel the aircraft 100. The thrust is generated by the turbine 35, which converts the excess bleed energy into shaft power. This power, in turn, powers the fan 45, compressing the air and creating additional air pressure in the ram air circuit 40. This pressure is output through the exhaust 42 to generate thrust. The exhaust 42 is configured to convert the air pressure into velocity to create thrust.

[0037]

[0047] 4 shows an overview of ECS pack 20 that utilizes excess pressure in bleed air to generate thrust through ram air circuit 40. Bleed air received by bleed flow circuit 30 has a high pressure above the pressure supplied to interior space 103. Instead of releasing this excess energy during cooling and supplying air to interior space 103, the excess energy is utilized to generate additional pressure in ram air circuit 40 and generate thrust at exhaust 42.

[0038]

[0048] In some embodiments during flight, the atmospheric air entering the ram air circuit 40 is boundary layer air. This boundary layer air is at a pressure lower than the total atmospheric pressure, resulting in high propulsive efficiency of the compression energy added to the ram air circuit 40.

[0039]

[0049] FIG. 5 illustrates the operation of the ram air circuit 40, in which ram air (i.e., atmospheric air) is introduced into the inlet 41 and supplied to the first and second heat exchangers 43a, 43b for cooling the bleed air as described above. A fan 45 moves the air downstream along the ram air circuit 40. The ram air is output from the heat exchangers 43a, 43b and directed to the exhaust 42 where it is output from the aircraft 100. As further shown in FIG. 5, the bleed flow circuit 30 includes bleed air introduced through the flow control valve 32. The bleed air travels through the first heat exchanger 43a and then to the compressor 34 before reaching the second heat exchanger 43b. The air from the second heat exchanger 43b travels through the turbine 35 and ultimately to the interior space 103.

[0040]

[0050] The compressor 34 and turbine 35 of the bleed flow circuit 30 are connected via a shaft 50 to the fan 45 of the ram air circuit 40. Excess air pressure from the second heat exchanger 43b is supplied to the turbine 35. This excess energy drives the turbine 35, which in turn drives the fan 45 at a higher speed, increasing the pressure of the air in the ram air circuit 40. This air is released at the exhaust 42 and generates thrust to propel the aircraft 100.

[0041]

[0051] In the embodiment of Figure 5, the fan 45 is positioned along the ram air circuit 40 upstream of the heat exchangers 43a, 43b. This relative placement allows for more efficient compression because it is more efficient to add heat after compression. In another embodiment, the fan 45 is positioned downstream from the heat exchangers 43a, 43b. Positioning the fan downstream from the heat exchanger 43 improves cooling of the bleed air because the heat of compression occurs after the heat exchanger 43.

[0042]

[0052] The fan 45 may be driven in a number of different ways. In some embodiments, the fan 45 is driven by warm air supplied through the bleed flow circuit 30. In other embodiments, the fan 45 is driven by a separate power source or from one or more other systems within the aircraft 100.

[0043]

[0053] In some embodiments, fan 45 moves ram air through ram air duct 40 when the movement of aircraft 100 through the atmosphere does not provide sufficient flow. In one embodiment, fan 45 operates to provide air when aircraft 100 is stationary on the ground. Bypass check valve 44 is positioned so that air bypasses fan 45 when the air is moving with sufficient flow (e.g., during flight).

[0044]

[0054] In some embodiments, the compressor 34 is bypassed in the bleed flow circuit 30. One embodiment, shown in FIG. 6, includes a bypass valve 37 disposed between the heat exchangers 43a and 43b. When the bypass valve 37 is closed, air from the first heat exchanger 43a is supplied to the compressor 34. The compressor 34 increases the pressure and temperature of the air and directs it to the second heat exchanger 43b. When the bypass valve 37 is open, the air from the first heat exchanger 43a bypasses the compressor 34 and is sent to the second heat exchanger 43b. In some embodiments, the bypass valve 37 bypasses the compressor 34 when sufficient cooling of the bleed air can occur without requiring the second heat exchanger 43b to receive the hotter bleed air due to the heat of compression of the compressor 34. The advantage of bypassing the compressor 34 is that all of the power generated by the turbine 35 is available for the fan 45 to add pressure to the ram air.

[0045]

[0055] 7 includes an ECS pack 20 in which a second heat exchanger 43b is located downstream from the turbine 35. Bleed air in the bleed flow circuit 30 travels through the first heat exchanger 43a to one or both of the compressor 34 and the turbine 35. Bleed air from the turbine 35 is then directed to the second heat exchanger 43b for further conditioning for delivery to the interior space 103. In this example, the turbine 35 generates more shaft power as a result of the higher input temperature of the turbine 35 due to the heat exchanger 43b being downstream from the turbine 35.

[0046]

[0056] 8 shows an embodiment in which both heat exchangers 43a, 43b are upstream from the fan 45 in the ram air circuit 40. Ram air enters the inlet 41 and is directed to the first heat exchanger 43a and the second heat exchanger 43b. The ram air is then directed to the fan 45. The advantage of this configuration, having the fan 45 downstream from the heat exchangers 43a, 43b, is that the heat of compression of the fan 45 occurs after the heat exchangers 43a, 43b, thus improving the effectiveness of the heat exchangers 43a, 43b.

[0047]

[0057] As shown in the above embodiments, ECS pack 20 has many of the elements that may be needed for a distributed propulsion system. This includes an energy source (in the form of excess air pressure energy), a device for converting the energy source into shaft power (i.e., turbine 35), a device for converting the shaft power into thrust (i.e., fan 45), and an inlet and outlet for ram air circuit 40. In some embodiments, one or both of inlet 41 and outlet 42 include variable geometry configurations. In some embodiments, ram air circuit 40 provides a desirable place to start with distributed propulsion because it currently exhausts below atmospheric pressure, and the work added to this circuit benefits from very high effective propulsive efficiency.

[0048]

[0058] In some embodiments, a control circuit 90 monitors the operation of the ECS pack 20 and the thrust generated through the ram air circuit 40. The control unit 90 is configured to provide ECS functionality that may be required while minimizing fuel consumption of the aircraft 100. In some embodiments, the control unit 90 minimizes fuel consumption by controlling one or more of the turbine nozzle area, the compressor bypass valve 37, the ram inlet 41 and outlet 42, and the ram air flow rate.

[0049]

[0059] As shown in FIG. 9 , the control unit 90 includes a processing circuit 91 and a memory circuit 92. The processing circuit 91 controls the overall operation of the ECS pack 20 according to program instructions stored in the memory circuit 92. The processing circuit 91 includes one or more circuits, microcontrollers, microprocessors, hardware, or combinations thereof. The memory circuit 92 includes a non-transitory computer-readable storage medium having stored thereon program instructions, such as a computer program product, that configure the processing circuit 91 to implement one or more of the techniques described herein. The memory circuit 92 may include various memory devices, such as, for example, read-only memory or flash memory. The memory circuit 92 may be a separate component as shown in FIG. 9 or may be incorporated into the processing circuit 91. Alternatively, the processing circuit 91 may omit the memory circuit 92, for example, according to at least some embodiments in which the processing circuit 91 is dedicated and non-programmable.

[0050]

[0060] Communications circuitry 93 is configured to receive signals from one or more of the components within ECS pack 20. Communications circuitry 93 is also configured to receive signals from other systems aboard aircraft 100, including, but not limited to, engine 106 and associated engine components. In one embodiment, communications circuitry 93 includes an interface configured to communicate with the components. In one embodiment, the interface operates according to the 802.11 standard, commonly known as a WiFi interface. Communications circuitry 93 is also configured to communicate with one or more of a flight control system 99 that monitors the operation of aircraft 100 and an engine control system that monitors the operation of engine 106. The communications circuitry 93 may also provide communications with one or more other systems aboard aircraft 100.

[0051]

[0061] User interface 94 provides a user on aircraft 100, such as flight personnel operating aircraft 100, with access to information about ECS pack 20. User interface 94 may include one or more input devices 95 and a display 96. In some embodiments, control unit 90 information is stored in a database 97. Database 97 may be separate from control unit 90, as shown in FIG. 9, or may be combined with control unit 90.

[0052]

[0062] In some embodiments, one or more sensors 98 are disposed within ECS pack 20 to sense one or more conditions (e.g., temperature, pressure, airflow) that send signals to control unit 90 for further operation and control of ECS pack 20.

[0053]

[0063] In some embodiments, control unit 90 is integrated into one or more other systems within aircraft 100. In some embodiments, control unit 90 is integrated into a larger control system. In some embodiments, control unit 90 is integrated into flight control system 99.

[0054]

[0064] 10 illustrates a method of generating thrust for the aircraft 100. The method includes receiving air from outside the aircraft 100 into the ram air circuit 40 (block 200). Bleed air is also received into the bleed flow circuit 30 (block 202). The bleed air is directed through at least one heat exchanger 43 to produce cooler bleed air (block 204). The bleed air that has passed through the at least one heat exchanger 43 is directed to the turbine 35 to power the turbine 35 (block 206). The turbine 35 then drives a fan in the ram air circuit 40. The fan increases the pressure of the air moving through the ram air circuit 40 (block 208). The air with increased pressure is exhausted through the outlet 42 of the ram air circuit 40 to generate thrust for the aircraft 100 (block 209).

[0055]

[0065] In some embodiments, the power supplied to the fan 45 is equal to the work done by the turbine 35. Therefore, the exhaust temperature of the air leaving the ram air circuit 40 is the same as if the excess pressure had been throttled away at the flow control valve 32.

[0056]

[0066] In some embodiments, the turbine 35 has variable inlet guide vanes 38 that can be adjusted to achieve a desired pack flow rate over a range of bleed pressures being supplied to the ECS pack 20. The variable inlet guide vanes 38 allow for efficient pack flow regulation without the need for a throttling device.

[0057]

[0067] The aircraft 100 may include one or more ECS packs 20. Each ECS pack 20 may receive bleed air from one or more sources. Each ECS pack 20 may also receive ram air from one or more ram air circuits 40.

[0058]

[0068] In some embodiments described above, bleed air is supplied from one or more of the engines 106. Additionally or alternatively, bleed air may be provided from the output of an auxiliary power unit (APU) or a turbocharger for a reciprocating engine.

[0059]

[0069] In some embodiments, a nozzle is disposed at the outlet 42 of the ram air circuit 40. The nozzle directs the flow of ram air out of the ram air circuit 40. The nozzle may control one or more of the flow, velocity, direction, pressure, and shape of the airflow exiting the ram air circuit 40. The nozzle is configured to generate thrust. The nozzle may have various cross-sectional shapes and sizes. In some embodiments, the nozzle is an adjustable variable area nozzle controlled by a control unit 90. The control unit 90 adjusts the nozzle to generate the desired thrust.

[0060]

[0070] In some embodiments, ECS pack 20 includes one or more additional components that utilize bleed air to pressurize ram air circuit 40. In some embodiments, ECS pack 20 includes a separate shaft that includes an air turbine connected to fan 45 on a single spool. In some embodiments, ECS pack 20 includes a turbine connected to a generator that powers an electric compressor.

[0061]

[0071] In some embodiments, the ram air circuit 40 includes separate fans for different modes of operation. A first fan 45 is used when the aircraft 100 is on the ground. A second fan 45 is used when the aircraft 100 is in flight. In some embodiments, a gearbox and clutch elements allow the turbine 35 to selectively power the two fans 45.

[0062]

[0072] In some embodiments, the ECS pack 20 includes one or more components for adding pressure to the ram air circuit 40 via something other than bleed air. In some embodiments, an electric motor powers a compressor that adds pressure to the ram air circuit 40. In some embodiments, a hydraulically driven compressor adds pressure to the ram air circuit 40. In some embodiments, a compressor powered by a cabin air outlet valve turbine adds pressure to the ram air circuit 40.

[0063]

[0073] In some embodiments, the ECS pack 20 includes a ram air circuit 40 and a bleed flow circuit 30. The bleed flow circuit 30 receives bleed air from a source (e.g., engine 106, APU). In other embodiments, the ECS pack 20 includes a fluid flow circuit. The fluid flow circuit receives fluid from a source (e.g., high-temperature working fluid for cooling, a condenser for a vapor cycle cooling system, a liquid cooling loop for power electronics). The fluid in the fluid flow circuit is cooled by the pack. This fluid may or may not be a power source. This power source drives a fan in the bleed flow circuit 30 to increase the thrust of the air exiting the ram air circuit 40.

[0064]

[0074] FIG. 11 illustrates an ECS pack 20 having a fluid flow circuit 300 and a ram air circuit 40. The fluid flow circuits 300 can have various configurations, such as pneumatic, hydraulic, or fuel systems. Each of them receives fluid from another system. The fluid flow circuit 300 cools the fluid and supplies the fluid to an output. The ram air circuit 40 receives air from the atmosphere outside the aircraft 100 at an inlet 41 and exhausts the air back into the atmosphere through an outlet 42. A turbine 301 in the fluid flow circuit 300 is connected to a fan 45 in the ram air circuit 40. Energy in the fluid drives the turbine 301. The turbine 301, in turn, drives the fan 45, increasing the compression of the air in the ram air circuit 40 and increasing the thrust of the air exiting through the outlet 42. Alternatively, the fluid flow circuit need not power the ram fan, which may be powered by an alternative power source, such as an electric motor.

[0065]

[0075] The present invention may, of course, be practiced otherwise than as specifically set forth herein without departing from the essential characteristics thereof. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced within their scope. [Explanation of symbols]

[0066] 20 Environmental Control System (ECS) Pack 30 Bleed flow circuit 31 Engine Bleed 32 Flow control valve 33 Air Mixing Valve 34 Compressor 35 Turbine (Air Cycle Machine) 36 Water separator 37 Bypass valve 38 Vane 39 ECS Bleed Flow 40 Ram Air Circuit 41 Entrance 42 Outlet 43 Heat exchanger 44 Bypass check valve 45 Fans 47 Duct 49 ECS ram cooling circuit 50 shaft 79 Duct 80 Duct 81 Duct 82 Duct 83 Duct 84 Duct 85 Duct 86 Duct 87 Duct 88 Duct 89 Duct 90 Control Unit 91 Processing circuit 92 Memory Circuit 93 Communication Circuit 94 User Interface 95 Input Devices 96 Display 97 Databases 98 Sensors 99 Flight Control System 100 aircraft 101 Torso 102 Main wing 103 Interior Space 104 cockpit 105 Cabin Area 106 Engine 300 Fluid Flow Circuit 301 Turbine Ram Air Bleed Air

Claims

1. 1. An aircraft environmental control system pack comprising: a ram air circuit (40) that receives air from the atmosphere outside the aircraft and exhausts the air back into the atmosphere through an outlet (42), the ram air circuit (40) including a fan (45) for directing the air toward the outlet (42); a bleed flow circuit (30) for receiving bleed air from an engine of the aircraft and cooling the air before it is supplied to an interior space (103) of the aircraft, the bleed flow circuit (30) comprising a turbine (35); the turbine (35) is operatively connected to the fan (45); Energy from the bleed air drives the turbine (35), which in turn drives the fan (45) to increase the compression of the air in the ram air circuit (40) and increase the thrust of the air exiting the ram air circuit (40).

2. 2. The environmental control system pack of claim 1, further comprising a shaft extending between the turbine and the fan, operatively connecting the turbine and the fan.

3. 2. The environmental control system pack of claim 1, wherein the ram air circuit (40) includes a heat exchanger (43), and the bleed air from the bleed flow circuit (30) travels through the heat exchanger (43) to reduce the temperature of the bleed air.

4. 4. The environmental control system pack of claim 3, wherein the fan (45) is positioned along the ram air circuit (40) upstream from the heat exchanger (43).

5. 2. The environmental control system pack of claim 1, wherein the turbine (35) includes variable nozzle guide vanes (38) for regulating the bleed air through the bleed flow circuit (30) to enable a predetermined flow rate over a range of pressures of the bleed air received from the engine.

6. 2. The environmental control system pack of claim 1, wherein the turbine (35) is configured to drive the fan (45) only when the aircraft is in flight.

7. 1. An aircraft environmental control system pack comprising: A ram air circuit (40), a duct (47) having an inlet (41) for receiving air from the atmosphere and an outlet (42) through which said air is exhausted back into said atmosphere; a fan (45) for directing said air through said duct (47); a ram air circuit (40) comprising one or more heat exchangers (43); and a bleed flow circuit (30) comprising a duct that directs bleed air to the one or more heat exchangers (43) and to an interior space (103) of the aircraft, the bleed flow circuit (30) comprising a turbine (35); the bleed air from the one or more heat exchangers (43) drives the turbine (35); The turbine (35) drives the fan (45) to increase the thrust produced by the ram air circuit (40).

8. 8. The environmental control system pack of claim 7, wherein the fan (45) is configured to increase the pressure of the air in the ram air circuit (40) when driven by the turbine (35).

9. 8. The environmental control system pack of claim 7, wherein the bleed flow circuit (30) further comprises a compressor (34), and the one or more heat exchangers (43) comprise a first heat exchanger (43a) positioned upstream from the compressor (34) and a second heat exchanger (43b) positioned downstream from the compressor (34) and upstream from the turbine (35).

10. 8. The environmental control system pack of claim 7, further comprising a bypass valve (44) disposed along the ram air circuit (40) and configured to direct the air away from the fan (45) during flight of the aircraft.

11. 8. The environmental control system pack of claim 7, further comprising a bypass valve (37) disposed along the bleed flow circuit (30) and configured to direct the bleed air from the first heat exchanger (43a) to the second heat exchanger (43b) and bypass a section of the bleed flow circuit (30).

12. 8. The environmental control system pack of claim 7, wherein the bleed air from a first heat exchanger (43a) drives the turbine (35), and a second heat exchanger (43b) is located downstream from the turbine (35).

13. 8. The environmental control system pack of claim 7, further comprising a control unit (90) configured to control one or more of a turbine nozzle, a compressor bypass valve (37), an inlet (41) and an outlet (42) of a ram air circuit (40), a ram flow rate, and a bleed air flow rate to minimize fuel consumption of the aircraft.

14. 8. The environmental control system pack of claim 7, wherein the ram air circuit (40) comprises either the fan (45) disposed downstream from the first heat exchanger (43 a) and the second heat exchanger (43 b), or the fan (45) disposed upstream from the first heat exchanger (43 a) and the second heat exchanger (43 b).

15. 1. A method of generating thrust in an aircraft, comprising: receiving air from outside the aircraft into a ram air circuit (40), the ram air circuit (40) comprising a fan (45) and one or more heat exchangers; receiving bleed air from an engine of said aircraft into a bleed flow circuit (30); directing the bleed air through the one or more heat exchangers (43) to reduce the temperature of the bleed air; directing the bleed air that has passed through the one or more heat exchangers (43) to a turbine (35) to power the turbine (35); Driving the fan (45) in the ram air circuit (40) with the turbine (35) to increase the pressure of the air passing through the ram air circuit (40); and exhausting the air having the increased pressure through an outlet (42) of the ram air circuit (40) to generate thrust for the aircraft.

16. 16. The method of claim 15, further comprising directing the bleed air through both a first heat exchanger (43a) and a second heat exchanger (43b) before directing the bleed air to the turbine (35).

17. 16. The method of claim 15, further comprising adjusting a nozzle at the outlet of the ram air circuit (40) to generate the thrust for the aircraft.

18. 16. The method of claim 15, further comprising directing the bleed air from the turbine (35) to a second heat exchanger (43b), the second heat exchanger (43b) being located downstream from the turbine (35) along the bleed flow circuit (30).

19. 16. The method of claim 15, further comprising directing the air through the first and second heat exchangers (43a, 43b) through the fan (45), with the fan (45) positioned upstream from the first and second heat exchangers (43a, 43b) along the ram air circuit (40).

20. 16. The method of claim 15, further comprising directing the air through a first heat exchanger (43a) and a second heat exchanger (43b) before directing the air through the fan (45), with the first heat exchanger (43a) and a second heat exchanger (43b) positioned upstream from the fan (45) along the ram air circuit (40).

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