US 12,292,008 B2
Engine system and method of operating the same
Peter Swann, Derby (GB)
Assigned to Rolls-Royce plc
Filed by ROLLS-ROYCE plc, London (GB)
Filed on Feb. 1, 2023, as Appl. No. 18/162,964.
Claims priority of application No. 2201987 (GB), filed on Feb. 15, 2022.
Prior Publication US 2023/0258136 A1, Aug. 17, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. F02C 9/40 (2006.01); F02C 3/22 (2006.01); F02C 7/22 (2006.01)
CPC F02C 9/40 (2013.01) [F02C 3/22 (2013.01); F02C 7/22 (2013.01); F05D 2220/323 (2013.01); F05D 2270/101 (2013.01); F05D 2270/306 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method of operating an engine system in which mechanical power is generated by combustion or oxidation of a fuel in an engine, wherein the fuel includes a first fuel and a second fuel different from the first fuel, the method comprising:
providing the first fuel from a first fuel store to the engine at a first mass flow rate;
providing the second fuel from a second fuel store to the engine at a second mass flow rate,
wherein the first mass flow rate and the second mass flow rate contribute to a total mass flow rate of fuel to the engine;
during a period of acceleration of the engine, increasing the relative fraction of the total mass flow rate of fuel represented by the second mass flow rate in order to control a surge margin of one or more compressors of the engine; and
controlling the relative fractions of the total mass flow rate of fuel provided by the first mass flow rate and the second mass flow rate to increase the surge margin during at least a portion of the period of acceleration compared to operation using only the first fuel during the at least a portion of the period of acceleration,
wherein all handling bleeds are closed during the at least a portion of the period of acceleration,
wherein the second fuel is selected to have a higher specific energy than the first fuel and to release a greater mass of water per unit mass of fuel than the first fuel, and
wherein the second fuel is a non-hydrocarbon fuel.
 
7. A method of operating an engine system in which mechanical power is generated by combustion or oxidation of a fuel in an engine, wherein the fuel includes a first fuel and a second fuel different from the first fuel, the method comprising:
providing the first fuel from a first fuel store to the engine at a first mass flow rate;
providing the second fuel from a second fuel store to the engine at a second mass flow rate, and
wherein the first mass flow rate and the second mass flow rate contribute to a total mass flow rate of fuel to the engine,
during a period of acceleration of the engine, increasing the relative fraction of the total mass flow rate of fuel represented by the second mass flow rate in order to control a surge margin of one or more compressors of the engine; and
controlling the relative fractions of the total mass flow rate of fuel provided by the first mass flow rate and the second mass flow rate such that:
the surge margin during at least a portion of the period of acceleration is the same as operating on only the first fuel during the at least a portion of the period of acceleration; and
the rate of acceleration is increased during the at least a portion of the period of acceleration compared to operation using only the first fuel during the at least a portion of the period of acceleration,
wherein the second fuel is selected to have a higher specific energy than the first fuel and to release a greater mass of water per unit mass of fuel than the first fuel,
wherein the second fuel is a non-hydrocarbon fuel.