FIELD OF THE INVENTION 0002 This invention relates to aircraft air conditioning systems, and more particularly to a cooling system for in flight entertainment system electronics.

BACKGROUND OF THE INVENTION 0003 Many systems are available for providing audio and video entertainment as well as telecommunications to airline passengers. Much of the innovation has concerned the enablement of higher fidelity systems to increase their appeal to passengers so that airborne systems compare with familiar ground entertainment systems. However the rapid proliferation of these electronic devices has added a significant burden to the host aircraft's power generation and air conditioning systems.

0004 Thermal management of (IFE) electronics is essential to maximizing the life of the electronics and preserving the quality of the aircraft cabin air conditioning.

Prior Art 0005 The prior art patent literature includes U. S. Patent No. 5,894,987 to Layne et. al. which discloses a ram air for cooling a heat generating component. Air is introduced through the air inlet and exhausted through an outlet. The component may be an electrical component, engine or engine part.

0006 U. S. Patent No. 5,474,120 to Severson et. al. shows the use of cool air to regulate the heat of electronics. The system has a primary and secondary source of cool air.

0007 U. S. Patent No. 3,930,553 to Greenough shows an aircraft cooling system having separate heat exchangers for the pilot and accessories. The accessory heat exchanger operates at higher temperatures than would otherwise be comfortable for occupants of an aircraft.

0008 U. S. Patent No. 2,825,212 to Darges et. al. discloses an aircraft heating and ventilating system which uses outside air having a duct. The temperature of the air is regulated by a controller.

0009 U. S. Patent No. 4,394,861 to Scortino is illustrative of a system for ducting outside air directly to a face mask. The outside air is used for breathing when the inside of the aircraft has become contaminated.

SUMMARY OF THE INVENTION 0010 It is an object of the present invention to satisfy the equipment cooling requirements of central command equipment of the (IFE) system.

0011 It is another object of the present invention to provide a cooling system necessary to manage the heat dissipated by the same equipment so that the airplane cabin environment will still be comfortable to passengers and crew.

0012 Accordingly there is provided a dedicated (IFE) electronics cooling system for extending the service life of the passenger entertainment system electronics and preserving the quality of the host aircraft's passenger air conditioning system.

BRIEF DESCRIPTION OF THE DRAWINGS 0013 FIG 1. is a simplified block diagram of air flow in the present forward (IFE) equipment cooling system; 0014 FIG 2. is a schematic representation of the present forward in flight entertainment cooling system; and, 0015 FIG 3. is illustrative of the valve control logic in the control means of the forward in flight entertainment equipment cooling system of FIG 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 0016 Turning now to FIG. 1 illustrative of the valves controlling air flow in the system of FIG. 2 it should be noted that the conditions for valve control in response to input signals are shown in FIG. 3.

0017 The large forward in flight entertainment cooling system, hereinafter called IFE shown in FIG 2. has a maximum capacity of-650 cubic feet per minute (cfm). Supply air 42 (a) is from forward of the cargo door. Forward supply fan 7 is installed in the supply manifold forward of the cargo door. The air is forced up by supply fan 7 through the supply manifold * (100), which comprises nine 2.25 inch diameter flex ducts running between frames and windows.

0018 Once the cooling air is run through the video control cabinet (hereinafter called VCC) (32) equipment, it is drawn up into the exhaust duct (34).

The exhaust duct (34) is equipped to collect exhaust air from any of the VCC locations, and is also connected directly to the distribution duct 38 (a), 38 (b) that bypasses the VCC (32). This exhaust system is comprised of a collection manifold 102, forward exhaust fan 6, forward smoke detector 5 plumbed across forward exhaust fan 6, followed by branches to overboard 34 (a) and mix bay 46. Branch 34 to overboard splits into ground exhaust branch 34 (a) and an in flight exhaust 34 (b). Ground exhaust system 34 (a) has two shutoffvalves, forward primary ventilation valve 1 and forward secondary ventilation valve 2 connected in series

prior to a split in ducting leading to two 3.25 inch diameter skin penetrations. Both inflight 34 (b) and ground outboard 34 (a) branches are located in the forward lower lobe of the aircraft. In flight exhaust branch 34 (b) has a single shutoff valve. Inboard exhaust branch 34 (b) to mix bay 34 (c) has a single shutoff valve 3. Control of the system through a programmable integrated circuit is accomplished by a printed circuit card assembly comprising control means 36 governed by the logic shown in FIG 3.

0019 During ground operations with the outside ambient temperature (OAT) greater than 45 degrees F, the IFE cooling system will exhaust heated air outside of the aircraft through both ventilation valves. Both ventilation valves 1 and 2 in ground overboard branch 34 (a), therefore are fully open, and forward shutoff valve 3 in the branch dumping inboard is closed while the aircraft is on the ground. If the aircraft is on the ground an the OAT is less than 45 degrees F., the cooling system will exhaust the heated air into mix bay 34 (c) and close ventilation valves 1 and 2 of the aircraft for preventing cold outside air from being drawn in from aircraft outflow valve 42 (b). In this scenario in a cold winter day, the heated air would be utilized to maintain warm temperature within the aircraft.

0020 System switching from ground to air mode is accomplished through air/ground signal 10 responsive to landing gear truck tilt. Once the air/ground transition from ground mode to air mode has occurred, ventilation valves 1 and 2 will be closed and the heated air will be exhausted overboard by forward IFE cooling overboard valve 4 whose overboard flow increases with altitude and cabin to ambient pressure differential. Some heated air will continue to be exhausted through forward inboard shutoff valve 3 until the aircraft reaches cruise altitude. Forward IFE cooling overboard valve 4 is closed only if one or more of the following conditions occur: 1) on the ground, or 2) if the electrical/electronic cooling mode is in the override mode, or 3) when the fire system is armed through input of signal 12, or 4) when aircraft pressurization is a concern. At all other times forward IFE cooling overboard valve 4 is open, allowing the venturi to draw up to 650 cfm overboard. This allows for the removal of VCC head end heat from the aircraft and

provides necessary pressure differential to ventilate the VCC during smoke mode.

With forward IFE cooling overboard valve 4 closed, and the IFE system operating, the heated air from the VCC will be blown inward to the mix bay.

0021 If smoke is detected in the present forward IFE cooling system during flight, all valves except forward IFE cooling overboard valve 4 will close to contain smoke, and all fans will be powered off.

0022 Although this invention has been illustrated and described in connection with the particular embodiment illustrated, it will be apparent to those skilled in the art that various changes may be made therein without departing from the spirit of the invention as set forth in the appended claims.