A fuel control device includes a stem fuel valve opening degree determination unit, a branch line flow rate determination unit, and a correction value determination unit. The stem fuel valve opening degree determination unit is configured to determine an opening degree of a flow rate adjustment valve of a stem fuel supply line. The branch line flow rate determination unit is configured to determine an opening degree of a flow rate adjustment valve of at least one branch line. The correction value determination unit is configured to determine a correction value of the opening degree of the flow rate adjustment valve of the at least one branch line based on a value of a pressure difference between a fuel pressure upstream of a nozzle connected to the at least one branch line and a corrected fuel pressure for a fuel pressure at an outlet.

A combustion staging system for fuel injectors of a multi-stage combustor of a gas turbine engine. The system includes plural fuel injectors, each having respective pilot and mains injection stages. It further includes a splitting unit which, to perform staging control of the combustor, receives a metered fuel flow and, for pilot and mains operation, controllably splits the received fuel flow into a pilot flow for injecting at the pilot stages of the injectors and a mains flow for injecting at the mains stages of the injectors, and for pilot-only operation, controllably splits the received fuel flow into a first part of the pilot flow for injecting at the pilot stages of a first portion of the injectors and a second part of the pilot flow for injecting at the pilot stages of a second portion of the injectors.

A fuel pump system has a start stage pump and a main stage pump. Fuel is supplied to the start stage pump at lower engine speeds. As the engine speed increases, the fuel system restricts fuel to the start stage pump via a pressure regulating valve and the main stage pump takes over. An electronically controlled shut-off valve limits the amount of fuel supplied to the pressure regulating valve and, hence, the start stage pump when closed to safeguard against operating the start stage pump at unsafe engine speeds.

A gas turbine engine for an aircraft. The gas turbine comprises a combustor, a fuel injection system connected with a source of fuel and configured to inject fuel into the combustor, a water injection system connected with a source of water and which is configured to inject water into the combustor, and a control system. The control system is configured to identify an atmospheric condition; determine a water-fuel ratio for injection into the combustor of the gas turbine engine in response to the atmospheric condition; and control injection of fuel and water by the fuel injection system and the water injection system according to said water-fuel ratio to control an soot emissions caused by combustion of fuel therein.

In one aspect of the present disclosure, there is provided a gas turbine engine. The gas turbine engine includes a primary gas path having, in fluid series communication: an air inlet, a compressor fluidly connected to the air inlet, a combustor fluidly connected to an outlet of the compressor, and a turbine section fluidly connected to an outlet of the combustor section. In embodiments, a hydrogen expansion turbine is in fluid communication to receive hydrogen from the gaseous hydrogen outlet of the heat exchanger. In certain embodiments, the gas turbine engine includes a heat exchanger having a gas conduit fluidly connected to the primary gas path, and a fluid conduit in fluid isolation from the gas conduit and in thermal communication with the gas conduit.

A fuel metering system includes a pump with an inlet and an outlet, a first flow path including a first valve fluidically connected to the outlet of the pump, and a second flow path including a second valve fluidically connected to the outlet of the pump, a third valve, and a fourth valve. An electrohydraulic servo valve in a first position hydraulically connects the inlet of the pump to the first, third, and fourth valves to close the first valve, open the third valve, open a first window of the fourth valve, and close a second window of the fourth valve. The electrohydraulic servo valve in a second position hydraulically connects the outlet of the pump to the first, third, and fourth valves to open the first valve, close the third valve, close the first window of the fourth valve, and open the second window of the fourth valve.

A metering valve has a main inlet port and a spool movable, and a housing outlet port in a housing. The spool has a metering inlet orifice selectively aligned with the main inlet port, and a metering outlet orifice selectively aligned with the main outlet port. The main inlet port communicates with the metering inlet orifice, and the outlet port communicates with the metering outlet orifice to each provide a metering orifice. The main outlet port communicates downstream to a minimum pressure valve. The minimum pressure valve has a piston biased to a closed position by a spring force, and a line downstream of the main outlet port acting against a face of the piston in opposition to the spring force to ensure a minimum pressure moving downstream past the piston to a use. A fuel system is also disclosed.

A metering valve has a shutoff position at which it blocks flow from the metering valve outlet line from reaching an outlet to a use. A spool has a first end and a second end. The housing has a first shoulder associated with the first end and a second shoulder associated with the second end. In the shutoff position, the spool has the first end spaced from the first shoulder, and the second end spaced from the second shoulder. A fuel system for a gas turbine engine is also disclosed.

A metering valve includes a valve body, a valve element, a rotary servo, and a stepper motor. The valve body has a valve chamber, a fluid inlet port, a fluid outlet port, a metering valve control pressure inlet port, a servo control pressure inlet port, and a servo control pressure outlet port. The valve element is movably disposed within the valve chamber and defines therein at least a control pressure chamber and a return pressure chamber. The valve element is responsive to fluid pressure in the control pressure chamber to move between a closed position and a plurality of open positions. The rotary servo is rotatable about a rotational axis to a plurality of servo positions to thereby vary fluid pressure in the control pressure chamber. The stepper motor is responsive to commands to rotate the rotary servo to a commanded servo position.

A fuel nozzle metering valve that includes a spool having an inlet port and an outlet flow port, and a retainer assembled to one end of the spool. A valve liner houses a portion of the spool. The spool is configured to move back and forth within the valve liner. The metering valve is biased in a closed position in which the outlet flow port is disposed entirely within the valve liner. The valve is opened when the spool slides within the valve liner such that some portion of the outlet flow port extends beyond an end of the valve liner. The retainer has a stepped portion configured to abut an end of the retainer at a fuel flow pressure below the expected maximum fuel flow pressure to be used in the fuel nozzle metering valve.