Method and controller for detecting ice

An example method of aircraft engine control includes detecting a difference between a temperature detected by a first temperature sensor and a temperature detected by a second temperature sensor. Anti-icing activity is initiated in response to the difference.

BACKGROUND

Aircraft may occasionally operate in environments having high concentrations of ice. In these environments, ice can buildup on the aircraft, sensors and engines. Ice buildup that becomes dislodged and moves into an engine of the aircraft can damage the engine or otherwise cause the engine to become unstable. Ice buildup on the engine that does not become dislodged can block airflow to the engine and cause power loss, for example.

As known, anti-icing activities can reduce the likelihood of ice buildup. For example, a pilot of the aircraft may open an anti-icing bleed on the engine if flying through an environment having a high concentration of ice. Anti-icing activities do have drawbacks. For example, anti-icing activities may decrease the overall efficiency of the engine. Because of their drawbacks, anti-icing activities are typically initiated only after detecting environmental conditions likely to contain ice.

Accurately detecting environmental conditions likely to contain ice is sometimes difficult. For example, some types of ice, such as High Altitude Ice Crystals, cannot be detected with currently available ice detection systems. Anti-icing activities are not initiated because they exist in atmospheric conditions that are not normally associated with environments likely to contain ice. Additionally, conventional anti-icing strategies available to date on aircraft have limited or no effect on this type of ice accretion. Relying on pilots to visually identify High Altitude Ice Crystals is highly unreliable.

SUMMARY

An example method of aircraft engine control includes detecting a difference between a temperature detected by a first temperature sensor and a temperature detected by a second temperature sensor. Anti-icing activity is initiated in response to the difference.

An example method of controlling a gas turbine engine includes detecting a first temperature using a first temperature sensor that is mounted to the gas turbine engine of an aircraft. The method compares the first temperature to a second temperature that is detected by a second temperature sensor mounted to a portion of the aircraft other than the gas turbine engine. The method initiates anti-icing activity in response to a difference between the first temperature and the second temperature.

An example anti-icing controller includes a controller that determines a difference between a first temperature detected by a first temperature sensor mounted to an aircraft and a temperature detected by a second temperature sensor mounted to an aircraft. The controller initiates anti-icing activity in response to the difference.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2, an example gas turbine engine10is used to propel an aircraft12. The engine10is circumferentially disposed about an axis X. The gas turbine engine10includes a fan14, a low-pressure compressor section16, a high-pressure compressor section18, a combustion section20, a high-pressure turbine section22, and a low-pressure turbine section24. Other example turbomachines may include more or fewer sections.

During operation, air is compressed in the low-pressure compressor section16and the high-pressure compressor section18. The compressed air is then mixed with fuel and burned in the combustion section20. The products of combustion are expanded across the high-pressure turbine section22and the low-pressure turbine section24.

The high-pressure compressor section18includes a rotor32. The low-pressure compressor section16includes a rotor34. The rotors32and34are configured to rotate about the axis X. The example rotors32and34include alternating rows of rotating airfoils or rotating blades36and static airfoils or static blades38.

The high-pressure turbine section22includes a rotor40coupled to the rotor32. The low-pressure turbine section24includes a rotor42coupled to the rotor34. The rotors40and42are configured to rotate about the axis X in response to expansion to drive the high-pressure compressor section18and the low-pressure compressor section16. The example rotors40and42include alternating rows of rotatable airfoils or rotatable blades44and static airfoils or static blades46, for example.

The examples in this disclosure are not limited to implementation in the two-spool gas turbine architecture described, and may be used in other architectures, such as a single-spool axial design, a three-spool axial design, and still other architectures. That is, there are various types of gas turbine engines, and other turbomachines, that can benefit from the examples disclosed herein.

An engine controller assembly50is coupled to a temperature sensor52(or probe) mounted near the fan14of the engine10. The sensor52senses the temperature of air entering the engine10. As can be appreciated, the sensor52may encounter High Altitude Ice Crystals54and other types of ice during operation. Although only the single sensor52is shown, other examples may include coupling the controller50to more than one sensor52mounted to the engine10, or multiple sensors mounted to other engines on the same aircraft.

The controller50is also coupled to a temperature sensor58mounted to a fuselage60of the aircraft12. The example sensor58is positioned on the fuselage60such that the sensor58may be substantially shielded from the impingement of ice crystals54as the aircraft12moves through air. For example, the sensor58may be positioned within a boundary layer64. Positioning the sensor58on the fuselage60, remote from the engine, and substantially shielded from the impingement of ice crystals54as the aircraft12moves through air reduces the likelihood of distorted temperature readings from the sensor58.

The High Altitude Ice Crystals54are a type or form of ice. The High Altitude Ice Crystals54may be mixed with other types of ice and/or water. The High Altitude Ice Crystals54, and other types of ice and/or water, can build-up on the engine10, and then break off or block airflow.

High Altitude Ice Crystals are a term of art that would be understood by a person having ordinary skill in this art. The Federal Aviation Administration has published a description of High Altitude Ice Crystals in FAA NPRM Notice No. 10-10, entitled “Airplane and Engine Certification Requirements in Supercooled Large Drop, Mixed Phase, and Ice Crystal Icing Conditions” (75 FR 37311, Docket No. FAA-2010-0636), which is incorporated herein by reference.

In one example, the High Altitude Ice Crystals54clog the sensor52as follows. First, the sensor52melts some of the High Altitude Ice Crystals54as the High Altitude Ice Crystals54move into the engine10. The melted High Altitude Ice Crystals54then refreeze within the sensor52, which clogs the sensor52. The clogged sensor52causes the sensor52to report incorrect temperatures readings to the controller50.

The clogged sensor52typically reports temperature readings that are incorrect because they are higher than the actual temperatures. The higher temperature readings may not indicate an environment having ice, even though the environment does contain ice in the form of the High Altitude Ice Crystals54. Again, the sensor58may be substantially shielded from the High Altitude Ice Crystals54. The sensor58thus does not typically clog.

Referring now toFIG. 3with continuing reference toFIGS. 1-2, the example controller50uses a method100to ensure that anti-icing activity is initiated even when the aircraft12is flying through environments having the High-Altitude Ice Crystals54that have clogged the sensor52.

The example method100includes detecting a first temperature reading at the temperature sensor52at a first step110. The method100then detects a second temperature reading at the temperature sensor58at a step120. At a step130, the controller50determines whether the first temperature reading from the step110is greater than the second temperature reading from the step120. If yes, the controller50automatically initiates anti-icing activity at a step140. If no, the controller50continues to monitor the first temperature reading and the second temperature reading. In the prior art, the sensors58and52would be used to detect temperature exclusively for the purpose of engine powersetting and aircraft flight management.

Example anti-icing activity initiated by the controller50may include continuously running engine igniters within the engine10. Other example anti-icing activity may include opening a stability bleed within the engine10, introducing more fuel to the engine10, or varying the position of vanes or other components within the compressor section18of the engine10.

Other anti-icing activity could include initiating an electrical or pneumatic anti-icing system within the engine10, or even initiating an alert, such as an audio or visual signal viewed by the pilot of the aircraft12. The alert may include notifying the pilot that the aircraft12is flying through an area having a high ice water content, so that the pilot can maneuver the aircraft12out of that area or engage manual anti-icing procedures. A person having skill in the art and the benefit of this disclosure would understand other types of anti-icing activity that could be initiated by the controller50.

In another example, the method100initiating anti-icing activity at the step140if the first temperature reading is greater than the second temperature reading at the step130, and if the aircraft12is in an area likely to include the High Altitude Ice Crystals54. Certain geographical areas, elevations, and known or predicted proximity to certain types of weather systems are more likely to include the High Altitude Ice Crystals54than other areas as is known.

In yet another example, the method100may include initiating at the step140if the first temperature reading is greater than the second temperature reading at the step130, and if the aircraft12is in an environment likely to include the High Altitude Ice Crystals54. Certain environments are more likely to include the High Altitude Ice Crystals54than other environments.

The example method100may maintain the anti-icing activity until the first temperature reading is no longer greater than the second temperature reading. The example controller50includes a processor70configured to execute the method100in the form of a program or an algorithm stored within a memory portion72of the controller50. Many computing devices can be used to implement various functions described herein. In terms of hardware architecture, the controller50may include one or more input and/or output (I/O) device interface(s) that are communicatively coupled via a local interface. The local interface can include, for example but not limited to, one or more buses and/or other wired or wireless connections. The local interface may have additional elements, which are omitted for simplicity, such as additional controllers, buffers (caches), drivers, repeaters, and receivers to enable communications. Further, the local interface may include address, control, and/or data connections to enable appropriate communications among the aforementioned components.

The example processor70used within the controller50executes software code, particularly software code stored in the memory portion72. The processor70can be a custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the computing device, a semiconductor based microprocessor (in the form of a microchip or chip set) or generally any device for executing software instructions.

The memory portion72can include any one or combination of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, VRAM, etc.)) and/or nonvolatile memory elements (e.g., ROM, hard drive, tape, CD-ROM, etc.). The memory portion72may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory portion72can also have a distributed architecture, where various components are situated remotely from one another, but can be accessed by the processor70.

The software in the memory portion72may include one or more additional or separate programs, each of which includes an ordered listing of executable instructions for implementing logical functions. A system component embodied as software may also be construed as a source program, executable program (object code), script, or any other entity comprising a set of instructions to be performed. When constructed as a source program, the program is translated via a compiler, assembler, interpreter, or the like, which may or may not be included within the memory portion72.

The Input/Output devices that may be coupled to system I/O Interface(s) may include input devices, for example but not limited to, a keyboard, mouse, scanner, microphone, camera, proximity device, etc. Further, the Input/Output devices may also include output devices, for example but not limited to, a printer, display, etc. Finally, the Input/Output devices may further include devices that communicate both as inputs and outputs, for instance but not limited to, a modulator/demodulator (modem; for accessing another device, system, or network), a radio frequency (RF) or other transceiver, a telephonic interface, a bridge, a router, etc.

Features of the disclosed example include initiating anti-icing activity to address High Altitude Ice Crystals even when temperature sensors do not report temperatures associated with ice.