A fuel system for a turbomachine includes a minimum pressure and shutoff valve (MPSOV) disposed between a fuel source and a fuel nozzle of a fuel system and configured to move between an opened position wherein fuel can flow to the fuel nozzle, and a closed position wherein fuel is prevented from flowing to the fuel nozzle, and a shutdown signal valve (SDSV) operatively connected to the MPSOV and configured to selectively supply a shutdown pressure to the MPSOV in a shutdown state such that the shutdown pressure forces the MPSOV to the closed position.

A fuel system for a turbomachine includes a minimum pressure and shutoff valve (MPSOV) disposed between a fuel source and a fuel nozzle of a fuel system and configured to move between an opened position wherein fuel can flow to the fuel nozzle, and a closed position wherein fuel is prevented from flowing to the fuel nozzle, and a shutdown signal valve (SDSV) operatively connected to the MPSOV and configured to selectively supply a shutdown pressure to the MPSOV in a shutdown state such that the shutdown pressure forces the MPSOV to the closed position.

A system for hindering the pilot from inadvertently turning off the fuel and/or engine when it is not safe is disclosed. In an embodiment, a fuel shutoff interlock is engaged if the aircraft is in the air and cross-side engine is not running. In an embodiment, a fuel shutoff interlock is not engaged if essential bus power is not present. In an embodiment, a fuel shutoff interlock is not engaged if the aircraft is on the ground. In an embodiment, a fuel shutoff interlock is not engaged if the cross-side engine is running.

A system for hindering the pilot from inadvertently turning off the fuel and/or engine when it is not safe is disclosed. In an embodiment, a fuel shutoff interlock is engaged if the aircraft is in the air and cross-side engine is not running. In an embodiment, a fuel shutoff interlock is not engaged if essential bus power is not present. In an embodiment, a fuel shutoff interlock is not engaged if the aircraft is on the ground. In an embodiment, a fuel shutoff interlock is not engaged if the cross-side engine is running.

A combustion staging system includes a splitting unit receiving a metered fuel flow and controllably splitting the received flow into pilot and mains flows for injecting at pilot and mains fuel stages performing staging combustor control. Pilot and mains fuel manifolds distribute fuel from the unit, which can select pilot-only and pilot and mains operations. A cooling flow recirculation line provides a cooling flow to the mains manifold during pilot-only operation, and a return section to collect mains manifold cooling flow. A fuel recirculating control valve open position allows the cooling flow to enter a delivery section during pilot-only operation; a shut off position prevents the cooling flow from entering the delivery section during pilot and mains operation. The unit can divert a mains flow portion into the delivery section during pilot and mains operation, the diverted portion re-joining the rest of the mains flow in the mains fuel stages.

A combustion staging system includes a splitting unit receiving a metered fuel flow and controllably splitting the received flow into pilot and mains flows for injecting at pilot and mains fuel stages performing staging combustor control. Pilot and mains fuel manifolds distribute fuel from the unit, which can select pilot-only and pilot and mains operations. A cooling flow recirculation line provides a cooling flow to the mains manifold during pilot-only operation, and a return section to collect mains manifold cooling flow. A fuel recirculating control valve open position allows the cooling flow to enter a delivery section during pilot-only operation; a shut off position prevents the cooling flow from entering the delivery section during pilot and mains operation. The unit can divert a mains flow portion into the delivery section during pilot and mains operation, the diverted portion re-joining the rest of the mains flow in the mains fuel stages.

A combustion staging system for fuel burners of a multi-stage combustor of a gas turbine engine is provided. The system has pilot and mains fuel manifolds respectively distributing fuel to pilot and mains stages of the burners. The system further has a plurality of check valves through which the mains manifold feeds fuel to the respective burners. The check valves are arranged to open when the fuel pressure within the mains manifold exceeds a predetermined fuel pressure relative to gas pressure in the combustor. The system further has a splitting unit which receives a metered fuel flow and controllably splits the received fuel flow into pilot and mains flows which are sent respectively to the pilot and mains fuel manifolds to perform staging control of the combustor. The splitting unit is operable to select the pilot manifold and to deselect the mains manifold for pilot-only operation in which there is a pilot supply to the combustor but no mains supply to the combustor from the burners. It is also operable to select both the pilot and mains manifolds for pilot and mains operation in which there are pilot and mains supplies to the combustor from the burners. The system further has a cooling flow recirculation line having a delivery section arranged to provide a cooling flow of fuel to the mains manifold when that manifold is deselected so that the deselected mains manifold remains primed with relatively cool fuel, and a return section arranged to collect the cooling flow from the mains manifold. The system further has a gas pressure sensor configured to measure gas pressure in the combustor, a speed sensor which measures a rotation speed of a rotor of the engine, and a control unit which, when the mains manifold is deselected for pilot-only operation, (i) compares the measured rotation speed with a predicted rotation speed for the metered fuel flow, and compares the measured gas pressure with a predicted gas pressure for the metered fuel flow, and (ii) is adapted to close off the recirculation line when the results of these comparisons are indicative of leakage of fuel from the cooling fuel flow into the combustor through one or more of the check valves.

A combustion staging system for fuel burners of a multi-stage combustor of a gas turbine engine is provided. The system has pilot and mains fuel manifolds respectively distributing fuel to pilot and mains stages of the burners. The system further has a plurality of check valves through which the mains manifold feeds fuel to the respective burners. The check valves are arranged to open when the fuel pressure within the mains manifold exceeds a predetermined fuel pressure relative to gas pressure in the combustor. The system further has a splitting unit which receives a metered fuel flow and controllably splits the received fuel flow into pilot and mains flows which are sent respectively to the pilot and mains fuel manifolds to perform staging control of the combustor. The splitting unit is operable to select the pilot manifold and to deselect the mains manifold for pilot-only operation in which there is a pilot supply to the combustor but no mains supply to the combustor from the burners. It is also operable to select both the pilot and mains manifolds for pilot and mains operation in which there are pilot and mains supplies to the combustor from the burners. The system further has a cooling flow recirculation line having a delivery section arranged to provide a cooling flow of fuel to the mains manifold when that manifold is deselected so that the deselected mains manifold remains primed with relatively cool fuel, and a return section arranged to collect the cooling flow from the mains manifold. The system further has a gas pressure sensor configured to measure gas pressure in the combustor, a speed sensor which measures a rotation speed of a rotor of the engine, and a control unit which, when the mains manifold is deselected for pilot-only operation, (i) compares the measured rotation speed with a predicted rotation speed for the metered fuel flow, and compares the measured gas pressure with a predicted gas pressure for the metered fuel flow, and (ii) is adapted to close off the recirculation line when the results of these comparisons are indicative of leakage of fuel from the cooling fuel flow into the combustor through one or more of the check valves.

An aircraft turbine engine including at least one spool rotating at speed N1 and a monitoring system including: a regulating module including at least one regulation measurement channel to obtain a measurement of the speed N1 and a mechanism to compare the obtained speed measurement with a thrust setpoint to provide a thrust status; and a module for engaging a protection function of UHT or ATTCS type of the turbine engine. The turbine engine further includes a system for protection against overspeed to prevent ejection of high-energy debris outside the turbine engine, the protection system including at least one overspeed measurement channel to obtain an overspeed of the rotating spool of the turbine engine. The engagement module compares at least one overspeed obtained with at least one reference speed defined according to the protection function to be engaged, to engage the protection function according to results of the comparison.

An aircraft turbine engine including at least one spool rotating at speed N1 and a monitoring system including: a regulating module including at least one regulation measurement channel to obtain a measurement of the speed N1 and a mechanism to compare the obtained speed measurement with a thrust setpoint to provide a thrust status; and a module for engaging a protection function of UHT or ATTCS type of the turbine engine. The turbine engine further includes a system for protection against overspeed to prevent ejection of high-energy debris outside the turbine engine, the protection system including at least one overspeed measurement channel to obtain an overspeed of the rotating spool of the turbine engine. The engagement module compares at least one overspeed obtained with at least one reference speed defined according to the protection function to be engaged, to engage the protection function according to results of the comparison.