Goodrich Control Systems Limited

Rolls-royce Corporation

Rolls-royce Controls and Data Services Limited

Rolls-royce Engine Control Systems Limited

Lucas Industries Limited

Michael Griffiths

Daniel James Bickley

Trevor Stanley Smith

Jonathan David Pye

Martin Kenneth Yates

Glyn Edward Dixon

Roger Southeran

Martin Richard Kirkman

Paul Bernard Green

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.

Combustion staging system

A combustion staging system is provided for fuel injectors of a multi-stage combustor of a gas turbine engine. The system has a splitting unit which receives a metered total fuel flow and controllably splits the metered total fuel flow into out-going pilot and mains fuel flows to perform pilot-only and pilot-and-mains staging control of the combustor. The system further has pilot and mains fuel manifolds which respectively receive the pilot and mains fuel flows. The system further has a plurality of mains flow scheduling valves which distribute the mains fuel flow from the mains fuel manifold to mains discharge orifices of respective injectors of the combustor. The system further has servo line which extends to the mains flow scheduling valves, the servo line being controllably fillable with pressurised fuel to change the pressure in the servo line relative to the pressure in the mains fuel manifold. Each mains flow scheduling valve has a chamber containing a movable piston, the chamber to a mains side of the piston being fed by the mains fuel manifold, and the chamber to a servo side of the piston being fed by the servo line. The piston has an open pilot-and-mains position which allows flow out of the mains side of the chamber to the mains discharge orifice of the respective injector. The piston is biased towards a closed pilot-only position which prevents flow out of the mains side of the chamber to the mains discharge orifice of the respective injector. The piston is movable to the closed position under an increase in pressure in the servo line relative to the mains fuel manifold.

A combustion staging system has a splitting unit receiving and splitting metered fuel flow into out-going pilot and mains flows; pilot and mains fuel manifolds receiving the pilot and mains flows; and parallel mains flow scheduling valves distributing the mains flow. The mains flow scheduling valves pass the pilot fuel flow to injector pilot discharge orifices. Each mains flow scheduling valve has a chamber containing a piston, the chamber to a piston pilot side communicating with the pilot fuel manifold and the chamber to a mains side of the piston communicating with the mains fuel manifold. The piston is biased towards a closed pilot-only position preventing flow out of the chamber mains side to the injector mains discharge orifice. The piston is movable under increased pressure in the mains fuel manifold to an open pilot-and-mains position allowing flow out of the chamber mains side to the injector mains discharge orifice.

An engine fuel control system is provided, including a supply line for the supply of fuel to a fuel metering valve which controls the flow of fuel to burners of an engine. Fuel is delivered at a first high pressure to the supply line by a pump arrangement. The engine fuel control system includes a restrictor located in the supply line for passage of the fuel delivered by the pump arrangement therethrough. The restrictor is configured such that fuel exiting the restrictor for onward supply to the fuel metering valve is at a second high pressure which is lower than the first high pressure. The engine fuel control system includes pressure limiting valves which actuate when the pressure difference between the first high and low pressure reaches a predetermined level to open a flow path for fuel on the supply line to by-pass the restrictor, thereby limiting the pressure difference.

Engine fuel control system

An engine fuel control system includes a fuel metering valve that controls the flow of fuel between supply and delivery lines which delivers fuel to engine burners. The fuel control system includes a fixed displacement main pump which receives fuel from a low pressure source and delivers the fuel at a first high pressure to the supply line, an augmenter pump which receives fuel from the low pressure source and delivers the fuel at a second high pressure to one or more fuel-pressure operated auxiliary engine devices, and a start valve which is actuated at low engine speeds to open a flow path which diverts fuel delivered by the augmenter pump away from the auxiliary engine devices to the supply line to augment the fuel delivered thereto by the main pump, the start valve being actuated at higher engine speeds to shut the flow path.

A fuel staging system is described which comprises a staging valveoperable to divide a metered fuel supply between a pilot delivery lineand a mains delivery line, and a recirculation valveconnected to the mains delivery lineand operable to permit a recirculation fuel flow to be supplied to the mains delivery linewhen the staging valveoccupies a position in which substantially no fuel is delivered to the mains delivery linethrough the staging valve

Fuel staging system

A fuel system comprises a supply unit operable to deliver a metered supply of fuel to a supply manifold, a staging valve operable to control the supply of fuel from the supply manifold to a pilot outlet and a main outlet, and control means operable to control the operation of the staging valve to control whether fuel is delivered through the pilot and/or main outlet thereof.

Fuel system

A fuel control system comprises a metering valve operable to control the flow of fuel between a supply line and a delivery line, a spill valve operable to control fuel flow within the supply line, a pressure raising valve connected to the delivery line, and a control servo valve movable between a thrust control mode in which it modifies the control of the spill valve to reduce the fuel flow delivered via the metering valve and an outlet of the pressure raising valve, and a windmill relight position in which it modifies the control of the pressure raising valve to allow fuel delivery through the outlet of the pressure raising valve at a reduced system pressure.

Fuel control system with servo valve controlled windmill relight mode

A fuel metering unit (FMU) comprising a metering valve operable to control the supply of fuel to a delivery chamber of a pressure raising valve (PRV), the PRV including a valve member movable under the influence of the pressure within the delivery chamber between a closed position and an open position in which fuel is able to flow from the delivery chamber to an outlet port, and a push piston movable under the influence of the pressure within a control chamber to urge the valve member towards its open position, wherein the control chamber communicates with a valve control port.

A fuel system is described that comprises a pressure raising and shut-off valve (PRSOV), and a control valve arrangement operable to control a fuel pressure applied to a part of the PRSOV urging the PRSOV towards a closed position, wherein the control valve arrangement is supplied with fuel at a pressure controlled by a variable fluid pressure potentiometer network including a variable flow restrictor which is variable in response to changes in the position occupied by the PRSOV.

A fuel supply system for a gas turbine engine comprises a first positive displacement pump (), a second positive displacement pump (), said first and second positive displacement pumps () being operable simultaneously for the supply of fuel from a low pressure source, and switching valve means () downstream of said first positive displacement pump () for changing a connection mode between said first and second positive displacement pumps () between a series mode and a parallel mode.

Fuel supply system

A method of monitoring the health of a positive displacement hydraulic pump comprising the steps of:

Pump health monitoring

An aircraft gas turbine engine fuel metering unit incorporating a memory device for storing data relevant to that unit, and an electrical connection arrangement whereby data can be read from and/or written to said memory device by an associated electronic engine controller, said stored data including data relating to at least one of the performance, the identification, the health, and the service life of that fuel metering unit. The invention further resides in an aircraft gas turbine engine fuel supply system and a method of operating such a system.

Engine fuel control

A fuel control system for a staged combustion engine comprising, a fuel metering unit including a fuel metering valve having a fuel metering orifice the opening of which is varied to meter the flow of fuel through the metering valve in use, a fuel staging unit receiving fuel from the metering valve of the fuel metering unit and incorporating a staging valve for dividing the flow of fuel from the fuel metering unit to pilot burner and main burner output lines, a connection between a fuel pressure region of said fuel metering unit and a port of said staging valve, and, overthrust detection means causing said staging valve, in response to overthrust detection, to connect said port of said staging valve to low pressure, whereby to drain fuel under pressure from said pressure zone of said fuel metering unit to low pressure to limit or reduce the fuel supplied from the fuel metering unit to the fuel staging unit and thus to the engine in use.

A fuel control system as claimed in claimwherein, the pressure raising valve includes: There is also disclosed a pressure raising valve for use in such a system.

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Bromsgrove, United Kingdom

Michael Griffiths