Patent ID: 11859554
Assignee: PRATT & WHITNEY CANADA CORP.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  B | IPC B  F

Claim 12:
13. A multi-engine system for an aircraft comprising:
a first engine and a second engine driving a common gearbox configured to drive a load, the first engine and the second engine respectively including a first compressor and a second compressor;
a pressure vessel external to the first engine and the second engine, the pressure vessel in fluid flow communication with one or both of the first and second compressors via: an accumulation flow path along which compressed air produced by one or both of the first and second compressors flows to reach the pressure vessel; and an injection flow path along which compressed air accumulated within the pressure vessel flows to reach an injection port in at least the second engine;
a valve in fluid communication with the accumulation flow path and the injection flow path, the valve being operable to move between a closed position and an open position, wherein in the open position the compressed air is permitted to flow either along the accumulation flow path or along the injection flow path;
a flow blocking system disposed in at least the second engine upstream of the injection port, the flow blocking system being configured to block a main gas path upstream of the injection port to prevent back-flow of the compressed air through the main gas path when the compressed air flows through the injection point into the second engine; and
an engine controller configured to control the first engine to operate in an active operating condition and to control the second engine to operate in a standby operating condition, wherein in the active operating condition the first engine provides sufficient power and/or rotor speed for demands for the aircraft, and in the standby operating condition the second engine provides provide minimal or no propulsive power to the aircraft, wherein the engine controller is in communication with the valve to control operation thereof, the engine controller operable to position the valve at one or more intermediate positions between the closed position and the open position, to control injection and extraction of compressed air through the accumulation flow path and the injection flow path.