A fuel system including a fuel tank, a first pump fluidly coupled to the fuel tank configured for distributing fuel from the fuel tank throughout the fuel system, and a second pump fluidly coupled to the first pump by a pressure regulating valve and configured for driving fuel to an engine.

A system for feeding operating gas to a drive (1) of a motor vehicle, including an atmosphere-side suction inlet (2a) for air under atmospheric pressure, and a feed line (2) for the operating gas to the drive (1) under an operating pressure, the operating gas which is conducted to the drive comprising at least part of the air which is sucked in, at least part of the operating gas being conducted through a turbomachine (3) upstream of the drive (1) in a first operating type, the turbomachine (3) comprising an electric generator (4), and the turbomachine (3) being operated in a second operating type as a compressor for the operating gas, an actuable valve arrangement (5) being provided, at least part of the air which is sucked in being conducted in a turbine direction (T) through the turbomachine (3) in a first position of the valve arrangement (5), and at least part of the air which is sucked in being conducted in a reversed compressor direction (V) through the turbomachine (3) in a second position of the valve arrangement (5).

A method for leak detection in a system including a compressor. A first pressure differential is determined in the system via a first pressure differential indicator (PDI). The first pressure differential is converted into a first flow measurement. A second flow measurement is determined downstream of the compressor using a second PDI. The first flow measurement and the second flow measurement are compared to determine whether a leak exists between the first PDI and the second PDI.

Methods and systems for supply of fuel for a turbine-driven fracturing pump system used in hydraulic fracturing may be configured to identify when the supply pressure of primary fuel to a plurality of gas turbine engines of a plurality of hydraulic fracturing units falls below a set point, identify a gas turbine engine of the fleet of hydraulic fracturing units operating on primary fuel with highest amount of secondary fuel available, and to selectively transfer the gas turbine engine operating on primary fuel with the highest amount of secondary fuel from primary fuel operation to secondary fuel operation. Some methods and systems may be configured to transfer all gas turbine engines to secondary fuel operation and individually and/or sequentially restore operation to primary fuel operation and/or to manage primary fuel operation and/or secondary fuel operation for portions of the plurality of gas turbine engines.

A turbofan engine has a primary duct , in which there flows a primary flow at a primary pressure and a secondary duct, which radially surrounds the primary duct and in which there flows a secondary flow at a secondary pressure. The primary duct includes at least one compressor configured to compress the primary flow , a turbine driving the compressor in rotation and a combustion chamber designed to receive, at an inlet, the primary air flow compressed by the compressor The turbomachine further includes a cooling circuit extending between the compressor and the turbine.The cooling circuit has an air flow rate regulating device arranged upstream of the turbine and having at least one valve that is configured to move between an open position and a closed position, located between the compressor and the combustion chamber in the primary duct and the pressure (PS) in the secondary duct.

The method can include determining a mass flow rate W of working fluid circulating through the compressor stage, determining a control parameter value associated to the geometrical configuration of the variable geometry element based on the determined value of mass flow rate W; and changing the geometrical configuration of the variable geometry element in accordance with the determined control parameter value.

An aspect of the present disclosure provides a diagnosis device for an internal combustion engine. The internal combustion engine 1 includes a variable geometry type turbocharger 14, and the turbocharger includes a variable vane 28, a link mechanism configured to operate the variable vane, and an actuator 29 configured to drive the link mechanism. The diagnosis device includes a control unit 100 configured to control an opening degree of the variable vane by controlling the actuator. The control unit determines that an abnormality has occurred in the link mechanism of the turbocharger when an operating time of the internal combustion engine in a predetermined operating region exceeds a predetermined upper limit value and a differential pressure between a target boost pressure determined according to an operating state of the internal combustion engine and an actual boost pressure exceeds a predetermined upper limit value.

A rotary machine system includes: a rotary machine including a gas seal portion; a gas seal device connected to the rotary machine and that supplies a seal gas to the gas seal portion; a pressure sensor that detects a pressure of the seal gas; a vent portion that discharges the seal gas discharged from the gas seal portion; and a vent pressure sensor that detects a pressure in the vent portion. The rotary machine includes: a casing through which a working fluid flows; a rotatable rotary shaft that passes; and the gas seal portion provided between the casing and the rotary shaft and that seals the working fluid by the seal gas having a pressure higher than a pressure of the working fluid in the casing. The gas seal device includes: a pressure regulating valve; and a control part that controls the pressure regulating valve.

A sensor apparatus comprising a housing having an inner perimeter which defines an area through which gas may flow, the housing being provided with a first chamber which extends around the area through which gas may flow, an entrance being distributed around the first chamber, and a second chamber which extends around the area through which gas may flow, an exit being distributed around the second chamber, the first chamber being arranged to be upstream of the second chamber in use, wherein the sensor apparatus further comprises one or more sensors arranged to measure a pressure difference between pressure in the first chamber and pressure in the second chamber. Corresponding turbocharger and method of measuring a mass flow rate are also provided.

A bleed air control system is configured to vary the air pressure at the inlet of a gas turbine engine. The bleed air control system includes a first gas turbine engine configured to provide bleed air, a second gas turbine engine acting as an auxiliary power unit, and a bleed air control system configured to selectively provide bleed air from the first gas turbine engine to the second gas turbine engine.