Passive cooling device and method for cooling an auxiliary power unit on an airplane
First Claim
1. A passive cooling system for an auxiliary power unit and an oil cooler for the auxiliary power unit on an airplane, comprising:
- a compartment positioned in the airplane, the auxiliary power unit and the oil cooler being positioned in the compartment;
an air intake duct extending between an inlet opening in an exterior surface of the airplane and the compartment, the intake duct defining an airflow passage through which the auxiliary power unit draws combustion air;
an outlet in a wall of the intake duct;
an inlet scoop mounted in the intake duct, the inlet scoop extending into the air passage from a point downstream of the outlet to a mouth positioned in the air passage upstream of the outlet, the inlet scoop diverting air from the intake duct through the outlet to a first side of the oil cooler; and
an aspirator, the aspirator creating a low-pressure region in a vacuum duct, the vacuum duct being coupled to a second side of the oil cooler so that air is drawn from the inlet scoop through the oil cooler and discharged through a vent.
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Accused Products
Abstract
A passive cooling system for aircraft auxiliary power units having an intake duct extending between an inlet opening and the compartment in which the auxiliary power unit is positioned. An inlet scoop is positioned in the intake duct for diverting a portion of the airflow in the intake duct through an outlet in a wall of the intake duct. A vacuum duct is positioned near an oil cooler for the auxiliary power unit, and an aspirator is operatively positioned between the vacuum duct and an exhaust passage of the auxiliary power unit. The aspirator creates a low-pressure region in the vacuum duct that draws the diverted air out of the outlet and through the oil cooler.
115 Citations
18 Claims
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1. A passive cooling system for an auxiliary power unit and an oil cooler for the auxiliary power unit on an airplane, comprising:
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a compartment positioned in the airplane, the auxiliary power unit and the oil cooler being positioned in the compartment; an air intake duct extending between an inlet opening in an exterior surface of the airplane and the compartment, the intake duct defining an airflow passage through which the auxiliary power unit draws combustion air; an outlet in a wall of the intake duct; an inlet scoop mounted in the intake duct, the inlet scoop extending into the air passage from a point downstream of the outlet to a mouth positioned in the air passage upstream of the outlet, the inlet scoop diverting air from the intake duct through the outlet to a first side of the oil cooler; and an aspirator, the aspirator creating a low-pressure region in a vacuum duct, the vacuum duct being coupled to a second side of the oil cooler so that air is drawn from the inlet scoop through the oil cooler and discharged through a vent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A passive cooling system for an auxiliary power unit and an oil cooler coupled to the auxiliary power unit on an airplane, the auxiliary power unit being positioned in a compartment in airplane, the cooling system comprising:
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an air intake duct extending between an inlet opening in an exterior surface of the airplane and the compartment, the intake duct defining an airflow passage through which the auxiliary power unit draws combustion air; an outlet in a wall of the intake duct; an inlet scoop mounted in the intake duct, the inlet scoop positioned in a portion of the air passage that diverts a portion of the airflow from the air passage through the outlet to a first side of the oil cooler; and an aspirator, the aspirator creating a low-pressure region in a vacuum duct, the vacuum duct being coupled to a second side of the oil cooler so that air is drawn from the inlet scoop through the oil cooler and discharged through a vent. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for passively cooling an auxiliary power unit and oil cooler coupled to the auxiliary power unit on an airplane, the method comprising the steps of
inducing an airflow in an intake duct, the intake duct extending between an inlet opening in an exterior surface of the airplane and a compartment in which the auxiliary power unit is positioned; -
diverting a portion of the airflow in the intake duct through an inlet scoop to the oil cooler, the inlet scoop being mounted in the intake duct in relationship to an outlet in a wall of the intake duct so that the diverted air will flow through the inlet scoop and out of the outlet; drawing the diverted air across the oil cooler to a vacuum duct, the vacuum duct being coupled the oil cooler on one side and an aspirator on another side; and discharging the air to the atmosphere.
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Specification