US 11,873,766 B2
Differential geared amplification of auxiliary power unit
Daniel Bernard Kupratis, Wallingford, CT (US); Neil J. Terwilliger, Cheshire, CT (US); and Michael M. Romero, Manchester, CT (US)
Assigned to RTX CORPORATION, Farmington, CT (US)
Filed by Raytheon Technologies Corporation, Farmington, CT (US)
Filed on Mar. 1, 2023, as Appl. No. 18/115,986.
Application 18/115,986 is a division of application No. 16/145,431, filed on Sep. 28, 2018, granted, now 11,629,646.
Prior Publication US 2023/0212985 A1, Jul. 6, 2023
Int. Cl. F02C 7/32 (2006.01); F02C 7/36 (2006.01); F16H 3/72 (2006.01)
CPC F02C 7/32 (2013.01) [F02C 7/36 (2013.01); F05D 2220/50 (2013.01); F05D 2260/40311 (2013.01); F16H 3/724 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A gas turbine engine assembly comprising:
a main gas turbine engine including a compressor section communicating compressed air to a combustor section where fuel is combined with the compressed air and ignited to generate a high energy flow that expands through a turbine section, wherein the turbine section is coupled to the compressor section by a main shaft;
an auxiliary power unit including an APU compressor coupled to an APU turbine section along an APU drive shaft;
a differential gear system including a ring gear and planet gears supported within a carrier attached to the ring gear, wherein the APU drive shaft is engaged to the planet gears;
a first drive means engaged to drive the ring gear;
an output shaft engaged to the planet gears; a generator driven by the output shaft;
a second drive means coupled to the main shaft of the main gas turbine engine for applying a partial drive load to the main shaft; and
a controller configured to control operation of the first drive means, the auxiliary power unit and the generator, where the controller is configured to: based on a determination that an increase in a demand for power on the generator is below a threshold demand, increase a speed of the first drive means to increase a power output from the generator to meet the demand while maintaining the APU at a constant speed; and based on a determination that the demand for power is above the threshold, increase the speed of the APU to increase the power output from the generator to meet the demand for power.