Patent ID: 9567906
Date: 2017-02-14
CPC Classifications: F02C,F05D

Claim:
1. An aircraft engine system, comprising: a main engine having a main engine speed; a starter coupled to the main engine and configured to drive the main engine; and an auxiliary power unit (APU) system coupled to the starter and configured to provide the compressed air to the starter, the APU system comprising wherein the compressor of the APU includes inlet guide vanes, and wherein the APU ECU is configured to adjust a position of the inlet guide vanes based on the main engine speed, wherein the APU further includes a surge control valve, and wherein the APU ECU is configured to adjust a position of the surge control valve based on the main engine speed, wherein the APU ECU controls operation of the APU based on a main engine cold motoring command to produce the amount of the compressed air to the starter such that a predetermined engine speed is achieved, and wherein, upon withdrawal of the main engine cold motoring command and receipt of an ignition command, the APU ECU is configured to adjust the position of the inlet guide vanes to a maximum position and the position of the surge control valve to a minimum position.