Auxiliary power unit adaptive cooldown cycle system and method
AssigneeHoneywell International Inc.
InventorsRobert Mallette, Bradley Volkmann
Life of this patent
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Abstract
A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.
Claims9
An auxiliary power unit (APU) system, comprising:
- an APU configured to rotate at a rotational speed;
- one or more sensors disposed within the APU, each of the one or more sensors configured to sense an operational parameter of the APU and supply a sensor signal representative of the operational parameter;
- and an APU control unit in operable communication with the APU and coupled to receive the sensor signals from the one or more sensors, the APU control unit further coupled to receive a shutdown signal and configured, in response to the shutdown signal, to:
- (i) reduce the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, (ii) determine, based on one or more of the sensor signals, when a lean blowout of the APU has occurred, and (iii) when a lean blowout has occurred, increasing the predetermined cooldown speed magnitude for use in a subsequent shutdown of the APU.
Dependencies are inferred from the claim text.