WO2008077101A1

WO2008077101A1 - Method and apparatus to facilitate ice-accumulation abatement

Info

Publication number: WO2008077101A1
Application number: PCT/US2007/088133
Authority: WO
Inventors: Ovidiu Gabriel Vlad; Jr. Lawrence Carl Spaete; Alfred Robert Zantow
Original assignee: Embedded Control Systems
Priority date: 2006-12-19
Filing date: 2007-12-19
Publication date: 2008-06-26
Also published as: WO2008077104A1

Abstract

A light source (401) is disposed in an aircraft (400) along with a light-to-electricity converter (403) and an optical pathway (404) that transports light (402) from that light source to the light-to-electricity converter. An energy storage component (407, 409) operably couples to the light-to-electricity converter to store at least some of the electricity from the light-to-electricity converter. At least one electrically-powered heating element (410) can be disposed on the aircraft in a location (411) where ice-accumulation abatement is desired and a heating element controller (413) then used to provide at least some of the stored electricity from the energy storage component to the electrically-powered heating element(s) in pulses (201, 301). These pulses can use a duty cycle that is insufficient to necessarily melt all ice but which is sufficient to melt ice such that other forces acting on the ice are able to effect removal of at least substantial portions of the ice.

Description

METHOD AND APPARATUS TO FACILITATE ICE-ACCUMULATION ABATEMENT

Related Application^)

[0001] This application claims the benefit of U.S. Provisional application number

60/870,699, filed December 19, 2006, which is incorporated by reference in its entirety herein.

Technical Field

[0002] This invention relates generally to ice abatement and more particularly to the abatement of ice on selected vehicle surfaces.

Background

[0003] The formation of ice on vehicula

Failure to prevent the formation of ice on certain aircraft surfaces (such as wing and stabilizer surfaces, propeller and rotor blade leading surfaces, and so forth) can greatly degrade the performance of that aircraft component.

[0004] As a result, various ice-accumulation abatement techniques are known in the art to discourage such occurrences. These ice-accumulation abatement techniques include de- icing (which comprises the known technique of removing already-formed ice from a given surface) and anti-icing (which comprises the known technique of preventing ice from forming on a given surface). Some aircraft use electrically heated resistive elements that are thermally coupled to the leading edges of surfaces of concern. Many such systems operate continuously. Upon first detecting icy conditions, many such systems first function as de- icing systems, then as anti-icing systems for the duration of the flight.

[0005] Though often effective for the intended purpose, present practices in this regard do not necessarily meet all operating circumstances and application settings. Brief Description of the Drawings

[0006] The above needs are at least partially met through provision of the method and apparatus to facilitate ice-accumulation abatement described in the following detailed description, particularly when studied in conjunction with the drawings, wherein:

[0007] FIG. 1 comprises a flow diagram as configured in accordance with various embodiments of the invention;

[0008] FIG. 2 comprises a signal timing diagram as configured in accordance with various embodiments of the invention;

[0009] FIG. 3 comprises a signal timing diagram as configured in accordance with various embodiments of the invention;

[0010] FIG. 4 comprises a block diagram as configured in accordance with various embodiments of the invention;

[0011] FIG. 5 comprises a schematic block diagram as configured in accordance with various embodiments of the invention; and

[0012] FIG. 6 comprises a block diagram as configured in accordance with various embodiments of the invention.

[0013] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein. Detailed Description

[0014] Generally speaking, pursuant to these various embodiments, an approach to ice-abatement in an aviation application setting can comprise disposing a light source in the aircraft, disposing a light-to-electricity converter in that aircraft, and providing an optical pathway to transport light from that light source to that light-to-electricity converter. An energy storage component can then be operably coupled to the light-to-electricity converter to store at least some of the electricity from the light-to-electricity converter. At least one electrically-powered heating element can be disposed on the aircraft in a location where ice- accumulation abatement is desired and a heating element controller then used to provide at least some of the stored electricity from the energy storage component to the electrically- powered heating elements) in pulses.

[0015] By one approach, these pulses can use a duty cycle that is insufficient to necessarily melt all ice as forms on the aircraft location where ice-accumulation abatement is desired but which is sufficient to melt ice in contact with the aircraft location such that other forces (such as air movement) acting on the ice are able to effect removal of at least substantial portions of the ice.

[0016] By one approach the energy storage component can comprise a rechargeable battery. By another approach, alone or in conjunction with the rechargeable battery, the energy storage component can comprise a capacitor. If desired, optical fiber can serve as the aforementioned optical pathway.

[0017] By one approach, the aforementioned light source is mounted within the aircraft such that waste heat from the light source is directed to a targeted aircraft location where ice-accumulation abatement is desired to thereby contribute to the ice-accumulation abatement. This can comprise, for example, disposing this light source near a wing of the aircraft and using a heat transport pathway to efficiently transport this waste heat from the light source to the targeted aircraft location. By one approach, use of the aforementioned electrically-powered heating element can comprise an anti-icing component while use of the aforementioned waste heat can comprise a de-icing component of these ice-accumulation abatement techniques.

[0018] So configured, these teachings serve well in an application setting where power is distributed about the aircraft using optical fibers rather than an electrical conductor such as copper. These teachings can provide an economical yet effective approach to abating ice formation on sensitive aircraft surfaces. Those skilled in the art will recognize and understand that these teachings are also highly leverageable and can be applied in an effective manner with respect to both small and large surfaces.

[0019] These and other benefits may become clearer upon making a thorough review and study of the following detailed description. Referring now to the drawings, and in particular to FIG. 1, an illustrative process 100 that is compatible with many of these teachings will now be presented.

[0020] This process 100 generally comprises an ice-accumulation abatement method that can be applied, for example, in conjunction with an aircraft. Other vehicle choices are of course possible. For the sake of example and the purposes of simplicity, however, the remainder of these descriptive examples will presume that the vehicle comprises an aircraft of choice.

[0021] This process 100 provides for disposing 101 a light source in the aircraft.

Various components will serve well in this regard. By one approach, the light source will comprise a high wattage source having one or more light emitting elements that collectively output, for example, multiple kilowatts of light energy in a spectral range of choice. In many application settings a frequency range within the visible spectrum and/or towards or in the infrared range may prove useful. This process 100 will accommodate, if desired, so disposing a plurality of light sources. A multiplicity of such components can serve to ensure, for example, a redundant supply of light sources. The light source can be placed as desired, though for some purposes (as explained below in more detail) it may be useful to locate the light source with more specific intent (such as highly proximal to a leading edge of a wing).

[0022] This process 100 also provides for disposing 102 a light-to-electricity converter in the aircraft. In a likely typical application setting, this will in fact comprise providing for a plurality of such light-to-electricity converters. So configured, the light-to- electricity converter can convert light as received from the light source via the optical pathway into electricity. Various light-to-electricity converters are known in the art (including, for example, various kinds of so-called solar cells) and others are likely to be developed going forward. Such components vary from one another with respect to weight, form factor, cost, operational efficiency, maintenance requirements, and so forth. Those skilled in the art will recognize and understand that the particular light-to-electricity components selected for use in a given application setting will therefore vary with respect to the needs and/or opportunities as tend to characterize that application setting.

[0023] This process 100 will accommodate optionally providing 103 an optical conduit that is disposed between the light source and the light-to-electricity converter to thereby convey the light from the light source to the light-to-electricity converter. Such an optical conduit can comprise, for example, a molded inflexible plastic lightpipe if desired. For many application settings, however, this optical conduit can be comprised of one or more optical fibers, including glass optical fibers and plastic optical fibers. To achieve a reduced cost and reduced weight, it may be preferable to utilize plastic optical fibers in an aviation setting.

[0024] This process 100 also provides for operably coupling 104 an energy storage component to the light-to-energy converter. This energy storage component can serve to store at least some of the electricity as is produced by the light-to-energy converter as stored electricity. Again, numerous energy storage components are known in the art that will suffice for this purpose. By one approach, for example, this energy storage component can comprise, at least in part, a rechargeable battery. As another example, in combination with a rechargeable battery or in lieu thereof, this energy storage component can comprise a capacitor. (Further details regarding possible options regarding a particular choice in this regard appear below where appropriate.)

[0025] So configured, the described components will permit, in a given application setting, light from one or more central sources of light to be distributed throughout an aircraft via the use of optical fibers. Such light, upon reaching individual termination points, can then be converted into electricity which is then stored in suitable storage mechanisms. By this approach, significant quantities of electricity can be rendered available at various locations about the aircraft, which quantities well exceed the instantaneous power delivery capabilities of the overall power distribution system.

[0026] This process 100 then provides for disposing 105 at least one electrically- powered heating element on the aircraft. Such elements can be placed in a location where, for example, ice-accumulation abatement is desired. Examples in this regard include, but are not limited to, the leading edges of wings and stabilizers, propeller edges, and rotor edges. The electrically-powered heating elements can themselves comprise, for example, resistive elements that tend to convert the flow of current into radiated heat energy. Materials and components that serve in this regard are well known in the art and require no further elaboration here. By one approach, such electrically-powered heating elements can be located on an external surface of the aircraft in order to most efficiently expose forming or accumulated ice to the aforementioned heat energy.

[0027] By one approach, such electrically-powered heating elements can be continuously provided with power from the aforementioned energy storage component. This, however, can consume considerable quantities of energy. This, in turn, can require a relatively large light source. Such an approach may be undesirable due to the weight and size requirements of this large light source.

[0028] To meet such a need, this process 100 will also accommodate using 106 a heating element controller to provide at least some of the stored electricity to the one or more electrically-powered heating elements in pulses. By one approach, such pulses, when provided, are issued in a regular periodic manner by the heating element controller. Less regular periodicity may be acceptable in some application settings, however.

[0029] The duty cycle of these pulses can also vary with respect to the needs and/or opportunities as pertain to a given application setting. For example, and referring momentarily to FIG. 2, a train 200 of such pulses can be comprised of individual pulses 201 that comprise, in the aggregate and by way of example, less than fifteen percent of the available duty cycle. As another example, and referring momentarily now to FIG. 3, another possibly useful train 300 of such pulses can be comprised of individual pulses 301 that collectively comprise, for example, more than fifteen percent but less than 30 percent of the available duty cycle. Again, the precise duty cycle can be varied as desired. For most purposes, however, the duty cycle can likely be less than fifty percent of the available duty cycle.

[0030] These relatively low duty cycles for these pulses are likely to be insufficient to necessarily melt all ice as forms on the aircraft location where ice-accumulation abatement is desired (i.e., in those locations where the electrically-powered heating element(s) has been disposed). Accordingly, this pulsed approach is likely to be inadequate as a de-icer (at least under some relatively typical operating conditions).

[0031] Nevertheless, such pulses can be sufficient to generate enough heat to melt ice that is in contact with the aircraft location where the electrically-powered heating element is located (though perhaps not beyond where the electrically-powered heating element is located). By melting this bit of ice, other forces that are also acting on the ice are now able to effect removal of at least substantial portions of the ice. For example, moving air that rushes over the surfaces of the aircraft's wings can work in combination with the thin layer of liquid water that now lies between the accumulated ice and the electrically-powered heating element to cause at least portions of the ice to become separated from the wing and break off.

[0032] It may be appropriate in some application settings to avoiding employing this approach in areas where potentially large chunks of broken ice may naturally fall back towards the engines of the plane (for example, when jet engines are mounted on the aircraft's rear stabilizer). Instead, such a pulsed application of warming energy may be better suited when deployed towards the outlying portions of the wings and other surfaces that avoid such an undesired happenstance.

[0033] As noted, the above techniques will serve readily enough as a de-icing technique that is primarily intended to remove already-formed ice. It may also be desirable, however, to also provide for anti-icing capability as well. To aid in this regard, this process 100 will further accommodate disposing the aforementioned light source at a location within the aircraft such that waste heat from the light source is readily directed to an aircraft location where ice-accumulation abatement is desired to thereby further contribute to the desired abatement functionality. This can comprise, for example, mounting the light source near a wing of the aircraft and can also comprise providing 107 at least one heat transport pathway between the light source and the targeted aircraft location to efficiently transport the waste heat from the light source to the targeted aircraft location to thereby contribute to the desired ice-accumulation abatement.

[0034] Various heat sink materials, such as aluminum, are known that will serve well in these regards. Generally speaking, the closer the light source is mounted to the area where application of the waste heat energy is intended to remove and/or prevent the formation of ice, the better the efficiency of the overall process. Such an approach can be employed, for example, to both effect anti-icing and de-icing at a portion of the wing that is relatively close to the aircraft's fuselage while also perhaps using the aforementioned pulse-based approach to effect de-icing at portions of the wing that are located further away from the fuselage. By this approach, the electrically-powered heating element comprises a de-icing component and the waste heat comprises an anti-icing component. [0035] Those skilled in the art will appreciate that the above-described processes are readily enabled using any of a wide variety of available and/or readily configured platforms, including partially or wholly programmable platforms as are known in the art or dedicated purpose platforms as may be desired for some applications. Referring now to FIG. 4, an illustrative approach to such a platform will now be provided.

[0036] In this illustrative embodiment, an aircraft 400 has a light source 401 disposed therein. This may comprise, for example, mounting the light source 401 in an equipment bay within the aircraft. This can also comprise coupling the light source 401 to a source of electricity for the aircraft to thereby power the light source. This light source 401 provides light 402 to a light-to-energy converter 403 of choice. Gallium arsenide-based solar cells, for example, can work well in this regard. By one approach, this light-to-energy converter 403 can provide an output of from 7.2 to 8.8 volts at a maximum power of about 10 watts. These values are of course completely optional and a given system designer is free to observe whatever values and metrics may be best suited to the needs and/or opportunities present in a given application setting.

[0037] This can comprise, for example, providing the light 402 via an optical conduit such as a plastic fiber optic cable 404. Use of such a cable 404 can provide considerable flexibility with respect to the installation of such an apparatus as such a cable 404 will convey light a considerable distance (for example, up to 100 meters).

[0038] In this illustrative embodiment, the output of the light-to-electricity converter

403 couples to two chargers 405 and 406. A first one of the chargers 405 can comprise a capacitor charging circuit as is known in the art having a nominal 20 volts output. This capacitor charging circuit works in conjunction with a capacitor 409 that is described further below and serves to maintain a charge on that capacitor 409 during ordinary usage scenarios. The second charger 406 comprises a rechargeable battery recharger (such as a lithium ion battery charger) as is known in the art. By one approach, this second charger 406 can serve to utilize power that is not otherwise used by the first charger 405. Accordingly, power may be applied only intermittently to this second charger 406.

[0039] The second charger 406 can be coupled, in turn, to a rechargeable battery 407 such as a 750 milliamp/hour lithium ion battery pack comprised of eight cells. Other sizes of battery packs, and other chemistries, can of course be utilized as desired. [0040] The outputs of these components ultimately feed a selector 408 that serves to selectively couple either the capacitor 409 or the rechargeable battery 407 to the output as needed to ensure the provision of adequate power for use by an electrically-powered heating element 410 that is disposed on the aircraft 400 in a location 411 where ice-accumulation abatement (such as de-icing) is desired. By one approach, this selector 408 can be configured and arranged to switch from the capacitor 409 to the battery 407 when there is no input from the light-to-energy converter 403 to power the capacitor charger 405 and/or when the capacitor 409 has become sufficiently depleted during use to require the resources of the battery 407.

[0041] If desired, the use of the battery's reserves in this manner can be supplemental to, rather than in place of, the capacitor charger 405. So configured, the capacitor 409 is essentially always coupled to the capacitor charger 405 but is also coupled to additionally receive power from the battery 407 as needed.

[0042] By one approach, the aforementioned capacitor 409 can comprise a so-called supercapacitor. Supercapacitors, also known as ultracapacitors or electrochemical double layer capacitors, are often electrochemical capacitors that have an unusually high energy density when compared to common capacitors (typically on the order of thousands of times greater than a high-capacity electrolytic capacitor). For instance, a typical D-cell sized electrolytic capacitor will have a storage capacity measured in microfarads, while the same size supercapacitor would store several farads, an improvement of about 10,000 times. Larger commercial supercapacitors have capacities as high as 3,000 farads. Use of a supercapacitor in this application setting therefore permits large quantities of power to be stored in reserve for use by the electrically-powered heating element 410 to effect desired de-icing functionality.

[0043] By one approach, this capacitor 409 can comprise a 2 to 10 farad (at 20 volts) supercapacitor. Such a capacitor can provide a considerable amount of power before needing to switch to the rechargeable battery 407 to provide the necessary instantaneous requirements of the described apparatus.

[0044] Those skilled in the art will recognize and understand that certain of the above described components, such as the battery 407 and the capacitor 409, can actually comprise a plurality of such components (configured, for example, in parallel with one another) to increase available energy reserves. [0045] As noted above, these teachings will accommodate pulsing the energy that is provided to the aforementioned electrically-powered heating element 410. To facilitate this mode of operation, this illustrative embodiment also comprises a heating element controller 413 that can utilize a corresponding switch 412 (or other comparable means) to provide energy to the electrically-powered heating element 410 in a pulsed manner. This can comprise, for example, configuring and arranging the heating element controller 413 to cause the delivery of stored energy to the electrically-powered heating element 410 using pulses as per a particular pre-selected duty cycle as described above. If desired, this heating element controller 413 can couple to one or more temperature sensors 414 to thereby facilitate determining when to begin applying energy to the electrically-operated heating element 410 as per these teachings.

[0046] As noted above, these teachings will also accommodate applying waste heat from the light source as a de-icing/anti-icing component. By this approach, the light source 401 is mounted in the aircraft 400 such that waste heat 415 from the latter is directed to a targeted aircraft location 416 (such as a wing surface) where ice-accumulation abatement (such as anti-icing) is desired. Referring now to FIG. 5, this can comprise, for example, mounting the light source 401 near a wing 504 of the aircraft 400. This can also comprise, if desired, providing at least one heat transport pathway 501 between the light source 401 and the targeted aircraft location (such as a leading edge 503 of the wing 504). This heat transport pathway 501 can comprise a good conductor of thermal energy such as aluminum or copper. In some cases, this can comprise physically joining the heat transport pathway 501 to a similar material 502 that itself comprises that portion of the wing 504 where ice- accumulation abatement is desired.

[0047] Those skilled in the art will recognize and appreciate that the aforementioned heating element controller 413 can comprise a fixed-purpose hard-wired platform or can comprise a partially or wholly programmable platform. All of these architectural options are well known and understood in the art and require no further description here.

[0048] Those skilled in the art will recognize and understand that such an apparatus maybe comprised of a plurality of physically distinct elements as is suggested by the illustration shown in FIG. 4. It is also possible, however, to view this illustration as comprising a logical view, in which case one or more of these elements can be enabled and realized via a shared platform. It will also be understood that such a shared platform may comprise a wholly or at least partially programmable platform as are known in the art.

[0049] So configured and arranged, those skilled in the art will recognize and appreciate that these teachings provide a highly flexible yet efficient mechanism by which ice accumulation can be abated. These teachings will support both anti-icing and de-icing functionality and will readily accommodate deployment with respect to a wide variety of aircraft surface form factors, relative size, and materials. These teachings are also readily usable in application settings where power is distributed within an aircraft as light rather than electricity.

[0050] Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.

[0051] To illustrate by way of example, and referring now to FIG. 6, these teachings are similarly applicable in application settings where the heating element is comprised of side glow cable. Unlike ordinary fiber optic cable, side glow cable permits light to exit from the sides of the cable as well as from the ends. By using an infrared light source 601, infrared light 603 can be carried via ordinary fiber 602 to a desired location 607 where ice- accumulation abatement is sought. A fiber junction 604 (as is known in the art) can transition the optical pathway to side glow cable 605 which is, in turn, disposed next to the location 607 where ice-accumulation abatement is desired. So configured, infrared light energy can exit from the sides of the side glow cable 605 as denoted by reference numeral 606. This energy 606, of course, will then serve to impart heat to the location 607 of interest and contribute to the anti-icing and/or de-icing process.

Claims

We claim:

1. An ice-accumulation abatement apparatus for use with an aircraft, the ice-accumulation abatement apparatus comprising: a light source configured and arranged to be disposed in the aircraft; a light-to-electricity converter configured and arranged to convert light from the light source into electricity; an energy storage component operably coupled to the light-to-electricity converter and being configured and arranged to store at least some of the electricity; at least one electrically-powered heating element configured and arranged to be disposed on the aircraft in a location where ice-accumulation abatement is desired; a heating element controller being configured and arranged to provide at least some electricity as is stored in the energy storage component to the at least one electrically- powered heating element in pulses, wherein the duty cycle of the pulses is insufficient to necessarily melt all ice as forms on the aircraft location where ice-accumulation abatement is desired but is sufficient to melt ice in contact with the aircraft location such that other forces acting on the ice are able to effect removal of at least substantial portions of the ice.

2. The ice-accumulation abatement apparatus of claim 1 wherein the energy storage component comprises both a rechargeable battery and a capacitor.

3. The ice-accumulation abatement apparatus of claim 1 further comprising: at least one optical conduit disposed between the light source and the light-to- electricity converter to thereby convey the light from the light source to the light-to- electricity converter.

4. The ice-accumulation abatement apparatus of claim 3 wherein the optical conduit comprises a plastic optical fiber.

5. The ice-accumulation abatement apparatus of claim 1 wherein the light source is further configured and arranged to be mounted in the aircraft such that waste heat from the light source is directed to an aircraft location where ice-accumulation abatement is desired to thereby contribute to the ice-accumulation abatement.

6. The ice-accumulation abatement apparatus of claim 5 wherein the light source is configured and arranged to be mounted near a wing of the aircraft.

7. The ice-accumulation abatement apparatus of claim 6 and further comprising: at least one heat transport pathway configured and arranged to efficiently transport the waste heat from the light source to a targeted portion of the wing of the aircraft to thereby contribute to the ice-accumulation abatement.

8. The ice-accumulation abatement apparatus of claim 5 wherein the at least one electrically- powered heating element comprises a de-icing component and the waste heat comprises an anti-icing component.

9. An ice-accumulation abatement method for use with an aircraft, the ice-accumulation abatement method comprising: disposing a light source in the aircraft; disposing a light-to-electricity converter in the aircraft; providing an optical pathway to transport light from the light source to the light-to- electricity converter; operably coupling an energy storage component to the light-to-electricity converter to store at least some of the electricity from the light-to-electricity converter in the energy storage compartment as stored electricity; disposing at least one electrically-powered heating element on the aircraft in a location where ice-accumulation abatement is desired; using a heating element controller to provide at least some of the stored electricity to the at least one electrically-powered heating element in pulses, using a duty cycle of the pulses that is insufficient to necessarily melt all ice as forms on the aircraft location where ice-accumulation abatement is desired but is sufficient to melt ice in contact with the aircraft location such that other forces acting on the ice are able to effect removal of at least substantial portions of the ice.

10. The ice-accumulation abatement method of claim 9 wherein the energy storage component comprises both a rechargeable battery and a capacitor.

11. The ice-accumulation abatement method of claim 9 wherein the optical pathway comprises a plastic optical fiber.

12. The ice-accumulation abatement method of claim 9 wherein disposing a light source in the aircraft comprises mounting the light source in the aircraft such that waste heat from the light source is directed to a targeted aircraft location where ice-accumulation abatement is desired to thereby contribute to the ice-accumulation abatement.

13. The ice-accumulation abatement method of claim 12 wherein disposing a light source in the aircraft comprises mounting the light source near a wing of the aircraft.

14. The ice-accumulation abatement method of claim 13 and further comprising: providing at least one heat transport pathway between the light source and the targeted aircraft location to efficiently transport the waste heat from the light source to the targeted aircraft location to thereby contribute to the ice-accumulation abatement.

15. The ice-accumulation abatement method of claim 12 wherein the at least one electrically- powered heating element comprises a de-icing component and the waste heat comprises an anti-icing component.