Gas turbine fuel control

Claim 2

A fuel supply system for a gas turbine engine comprising a pump for delivering fuel under pressure, a metering head regulating by-pass valve connecting the outlet of the pump to the pump inlet, a fuel metering valve supplied by the pump, and a fuel delivery conduit to the engine combustion apparatus supplied through the fuel metering valve, in combination with controlling means comprising; a settable power level control; means responsive to combustion chamber pressure; multiplying means actuated by the power level control and the pressure responsive means operative to control the metering valve to maintain metering vAlve effective area a predetermined function of the product of the said pressure and the power level setting; means responsive to ambient air temperature; and means actuated by pressure drop across the metering valve and the temperature responsive means operative to control the by-pass valve to maintain metering head proportional to ambient temperature.

Claim 3

A system as recited in claim 1 in which the pressure responsive means is calibrated to provide an output substantially proportional to absolute pressure.

Claim 4

A system as recited in claim 1 in which the temperature responsive means is calibrated to provide an output substantially proportional to absolute temperature.

Claim 5

A system as recited in claim 3 in which the pressure responsive means is calibrated to provide an output substantially proportional to absolute pressure.

Claim 6

A fuel supply system for a gas turbine engine comprising a pump for delivering fuel under pressure, a metering head regulating by-pass valve connecting the outlet of the pump to the pump inlet, a fuel metering valve supplied by the pump, a cutoff valve supplied through the metering valve, and a fuel delivery conduit to the engine combustion apparatus supplied through the cutoff valve, in combination with controlling means comprising; a settable power level control; means responsive to combustion chamber pressure; multiplying means actuated by the power level control and the pressure responsive means operative to control the metering valve to maintain metering valve effective area a predetermined function of the product of the said pressure and the power level setting; means responsive to ambient air temperature; means actuated by pressure drop across the metering valve and the temperature responsive means operative to control the by-pass valve to maintain metering head proportional to ambient temperature; means responsive to pressure in the fuel delivery conduit biasing the cutoff valve to close; and means responsive to the power level control biasing the cutoff valve to open, so that the cutoff valve closes when delivered fuel pressure exceeds that required by the power level control.

Claim 7

A fuel supply system for a gas turbine engine comprising a pump for delivering fuel under pressure, a metering head regulating by-pass valve connecting the outlet of the pump to the pump inlet, a fuel metering valve supplied by the pump, a cutoff valve supplied through the metering valve, and a fuel delivery conduit to the engine combustion apparatus supplied through the cutoff valve, in combination with controlling means comprising; a settable power level control; means responsive to combustion chamber pressure; multiplying means actuated by the power level control and the pressure responsive means operative to control the metering valve to maintain metering valve effective area a predetermined function of the product of the said pressure and the power level setting; means responsive to ambient air temperature; means actuated by pressure drop across the metering valve and the temperature responsive means operative to control the by-pass valve to maintain metering head proportional to ambient temperature; means responsive to pressure in the fuel delivery conduit biasing the cutoff valve to close; and means responsive to the power level control biasing the cutoff valve to open, so that the cutoff valve closes when delivered fuel pressure exceeds that required by the power level control.

Claim 8

A fuel supply system for a gas turbine engine comprising a pump for delivering fuel under pressure, a metering head regulating by-pass valve connecting the outlet of the pump to the pump inlet, a fuel metering valve supplied by the pump, a cutoff valve supplied through the metering valve, and a fuel delivery conduit to the engine combustion apparatus supplied through the cutoff valve, in combination with controlling means comprising; a settable power level control; means responsive to combustion chamber pressure; multiplying means actuated by the power level control and the pressure responsive means operative to control the metering valve to maintain metering valve effective area a predetermined function of the product of the said pressure and the power level setting; means responsive to ambient air temperature; means actuated by pressure drop across the metering valve and the temperature responsive means operative to control the by-pass valve to maintain metering head proportional to ambient temperature; means responsive to pressure in the fuel delivery conduit biasing the cutoff valve to close; and means responsive to the power level control biasing the cutoff valve to open with a force increasing with increasing power signal, so that the cutoff valve closes when delivered fuel pressure exceeds that required by the power level control.

Claim 9

A fuel supply system for a gas turbine engine comprising a pump for delivering fuel under pressure, a metering head regulating by-pass valve connecting the outlet of the pump to the pump inlet, a fuel metering valve supplied by the pump, a cutoff valve supplied through the metering valve, and a fuel delivery conduit to the engine combustion apparatus supplied through the cutoff valve, in combination with controlling means comprising; a settable power level control; means responsive to combustion chamber pressure; multiplying means actuated by the power level control and the pressure responsive means operative to control the metering valve to maintain metering valve effective area a predetermined function of the product of the said pressure and the power level setting; means responsive to ambient air temperature; means actuated by pressure drop across the metering valve and the temperature responsive means operative to control the by-pass valve to maintain metering head proportional to ambient temperature; means responsive to pressure in the fuel delivery conduit biasing the cutoff valve to close; and means responsive to the power level control biasing the cutoff valve to open with a force increasing with increasing power signal, so that the cutoff valve closes when delivered fuel pressure exceeds that required by the power level control.

Claim 10

A fuel supply system for a gas turbine engine comprising a pump driven by the engine, a fuel metering valve for controlling flow of fuel from the pump to the engine, and a by-pass valve connected for flow from the pump outlet to the pump inlet effective to regulate the head across the metering valve and return excess pumped fuel to the pump inlet, the system being characterized by a connection from the pump to the inlet of the by-pass valve such that the by-pass valve inlet is subjected to total static plus dynamic pressure of the pumped fuel and by a connection from the pump to the inlet of the metering valve such that the metering valve is subjected substantially to the static pressure only of the pumped fuel.

Claim 11

A fuel supply system for a gas turbine engine comprising a pump driven by the engine, a fuel metering valve for controlling flow of fuel from the pump to the engine, and a by-pass valve connected for flow from the pump outlet to the pump inlet effective to regulate the head across the metering valve and return excess pumped fuel to the pump inlet, the system being characterized by a connection from the pump to the inlet of the by-pass valve such that the by-pass valve inlet is subjected to total static plus dynamic pressure of the pumped fuel and by a connection from the pump to the inlet of the metering valve such that the metering valve is subjected substantially to the static pressure only of the pumped fuel.

Claim 12

A fuel supply system for a gas turbine engine comprising a pump driven by the engine, a fuel metering valve for controlling flow of fuel from the pump to the engine, and a by-pass valve connected for flow from the pump outlet to the pump inlet effective to regulate the head across the metering valve and return excess pumped fuel to the pump inlet, the system being characterized by a connection from the pump to the inlet of the by-pass valve such that the by-pass valve inlet is subjected to total static plus dynamic pressure of the pumped fuel and by a connection from the pump to the inlet of the metering valve such that the metering valve inlet is subjected substantially to the static pressure only of the pumped fuel, the said connections including a pump discharge conduit, a first conduit constituting a coaxial continuation of the pump discharge conduit leading to the metering valve inlet, the fuel in the said conduits flowing in the same direction, and a second conduit concentric with the pump discharge conduit leading from the pump discharge conduit to the metering valve, the direction of flow in the second conduit being opposite to that in the pump discharge conduit.

Claim 13

A fuel supply system for a gas turbine engine comprising a pump driven by the engine, a fuel metering valve for controlling flow of fuel from the pump to the engine, and a by-pass valve connected for flow from the pump outlet to the pump inlet effective to regulate the head across the metering valve and return excess pumped fuel to the pump inlet, the system being characterized by a connection from the pump to the inlet of the by-pass valve such that the by-pass valve inlet is subjected to total static plus dynamic pressure of the pumped fuel and by a connection from the pump to the inlet of the metering valve such that the metering valve inlet is subjected substantially to the static pressure only of the pumped fuel, the said connections including a pump discharge conduit, a first conduit constituting a coaxial continuation of the pump discharge conduit leading to the metering valve inlet, the fuel in the said conduits flowing in the same direction, and a second conduit concentric with the pump discharge conduit leading from the pump discharge conduit to the metering valve, the direction of flow in the second conduit being opposite to that in the pump discharge conduit.