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US 5,313,202 AGranted
Method of and apparatus for detection of ice accretion
AssigneeMassachusetts Institute of Technology
InventorsRobert J. Hansman, Jr., Adam L. Dershowitz
Life of this patent
Estimating the term…
Abstract
Method and apparatus for detecting icing, particularly on airfoils such as helicopter rotor blades, by detecting warming caused by latent heat released as water freezes. The sensors may be multiple or single, contact or remote.
Claims19
Apparatus for detecting ice on a surface, said apparatus comprising:
- passive infrared sensor means for receiving infrared radiation emitted by an ice accretion region on the surface and for generating a signal indicative of a characteristic of said infrared radiation;
- and
- means, responsive to said passive infrared sensor means, for detecting ice in said ice accretion region at least partially on the basis of said signal,
- wherein the surface is at least part of a surface of an airfoil of an aircraft, the ice accretion region occurring at a leading edge of the airfoil, and wherein the passive infrared sensor means comprises a passive infrared sensor mounted on a fuselage of the aircraft.
1 more element
Apparatus for detecting ice on a rotor blade of a helicopter, comprising:
- passive infrared sensor means mounted on a fuselage of the helicopter and aimed so that a leading edge ice accretion region of the rotor blade passes through a field of view of the passive infrared sensor means, said passive infrared sensor means thus receiving infrared radiation emitted by said leading edge ice accretion region when said leading edge ice accretion region of the rotor blade passes through the field of view of the passive infrared sensor, said passive infrared sensor means generating a signal indicative of a characteristic of the received infrared radiation;
- and
- means, responsive to said passive infrared sensor means, for detecting ice in said leading edge ice accretion region at least partially on the basis of said signal.
Apparatus for directly detecting ice on a constituent surface of interest, the apparatus comprising:
- first means for sensing a first temperature of the surface at an ice accretion region on the surface, said first means comprising a remote infrared sensor arranged to at least intermittently receive infrared radiation from the ice accretion region;
- second means for determining a second temperature of the surface at a position where ice does not accrete;
- third means, responsive to the first means and the second means, for determining when an icing condition exists based on a magnitude of a difference between the first temperature and the second temperature;
- and
- means for directing infrared radiation from the ice accretion region to the infrared sensor during a first time interval and from the position where ice does not accrete to the infrared sensor during a second time interval distinct from the first time interval, such that the infrared sensor serves as both the first means and the second means.
2 more elements
Apparatus for directly detecting ice on a surface of an airfoil of an aircraft, the apparatus comprising:
- first means for sensing a first temperature of the surface at an ice accretion region on the surface;
- second means for determining a second temperature of the surface at a position where ice does not accrete;
- and
- third means, responsive to the first means and the second means, for determining when an icing condition exists based on a magnitude of a difference between the first temperature and the second temperature,
- wherein the ice accretion region is at a leading edge region of the airfoil, and the first means comprises a remote infrared sensor mounted on a fuselage of the aircraft.
2 more elements
A helicopter comprising:
- a fuselage;
- a rotor blade rotatably mounted on the fuselage;
- an infrared sensor, mounted on the fuselage and arranged to have a field of view through which the rotor blade passes chordwise as the rotor blade rotates, said infrared sensor producing a signal indicative of the infrared radiation emitted by a portion of said rotor blade within said field of view;
- and
- means, within the fuselage and responsive to the infrared sensor, for determining based on said signal from said infrared sensor, the magnitude of a difference in temperature between a leading edge of the rotor blade and a position on the rotor blade streamwise displaced from the leading edge.
2 more elements
Dependencies are inferred from the claim text.