Systems, methods and apparatus are disclosed for providing or maintaining a target surge margin at the compressor during steady state engine operating conditions and to avoid compressor surge during transients by controlling a compressor recirculation valve position to a commanded position. The estimated surge margin can be determined in response to the measured pressure ratio across the compressor, an estimated compressor flow, and a compressor map for the compressor.

An illustrative example embodiment of a compressor includes an inlet defining an intake passage, a plurality of inlet guide vanes, an impeller, and a plurality of swirl nozzles. Fluid flow through the plurality of inlet guide vanes into the intake passage is selectively adjustable to control fluid flow through at least the portion of the intake passage downstream of the swirl nozzles. The impeller includes a plurality of blades and directs fluid from the intake passage toward an outlet. The swirl nozzles have outlets positioned downstream of the plurality of inlet guide vanes and upstream of the impeller. The swirl nozzles are configured to introduce fluid into the intake passage to cause swirl of fluid in the intake passage between the plurality of inlet guide vanes and the impeller.

In a turbocharged internal combustion engine (ICE) system, a catalytic treatment device receives exhaust gases from the ICE after they have passed through the turbocharger turbine. The system includes a secondary air pump (SAP) for injecting pressurized air into the exhaust gases ahead of the catalytic treatment device. The SAP is a single-stage centrifugal compressor that includes an air recirculation passage for causing a first portion of the air pressurized by the SAP to be continuously recirculated back to the inlet of the SAP, which is effective for heating the air in the volute of the SAP. A second portion of the pressurized air, having thereby been heated, is injected into the exhaust gases proceeding toward the catalytic treatment device.

A waste gate assembly for a turbocharger includes a valve member formed by a valve shaft and an arm attached to an end of the shaft, the arm defining a through bore, an inner surface of the through bore defining an arm groove therein. A poppet for the valve has a pin whose outer surface defines a pin groove. A generally polygonal retaining ring of elastically deformable wire is installed partially in the arm groove and partially in the pin groove to retain the poppet on the pin, thereby attaching the poppet to the arm of the valve member. An anti-rotation feature prevents relative rotation of the poppet about the pin axis. Vertices of the retaining ring are in the arm groove, while sides of the retaining ring are in the pin groove. Once the retaining ring is pre-installed in the arm groove of the arm, the arm can be assembled to the poppet by a push-to-connect process.

A centrifugal compressor and a method of operating a centrifugal compressor. The centrifugal compressor includes: an impeller configured to suction a gas to be compressed; a diffuser disposed downstream of the impeller to pressurize the gas, the diffuser comprising a movable ring, a main passage in which the gas flows past the ring, and an openable branch passage; and a circulation loop comprising an inlet and an outlet, the outlet being in communication with an inlet of the impeller; the branch passage is disposed to be in communication with the main passage and the circulation loop when the ring moves into the main passage so that a portion of the gas in the main passage passes through the circulation loop and returns to the impeller so as to be suctioned, and to be closed when the ring is withdrawn from the main passage.

A casing treatment for a compressor includes one or more cavities in a casing disposed radially outwardly of tips of the compressor rotor blades. A liner is moveable relative to the casing between a first position and a second position. The liner is shaped to add a volume to the tip clearance gap when moving from the second position toward the first position. The liner is displaceable between the first and second positions in coordination with at least the rotation of inlet guide vanes (IGVs) between IGV positions.

Automatic testing for control valves is provided for diagnosing of actuators, including actuators not equipped with analog or discrete position transmitters. A valve controller confirms steady-state conditions for a turbo-compressor system that includes a control valve in a first position and sends, to an actuator for the control valve, a signal to initiate a partial valve stroke to move the control valve away from the first position. The valve controller receives feedback signals from sensors in the turbo-compressor system and monitors the feedback signals for a change from the steady-state conditions. When the monitoring detects a change from the steady-state conditions within a defined time period, the valve controller sends, to the actuator, a signal to return the control valve to the first position. When the monitoring does not detect a change from the steady-state conditions within the defined time period, the valve controller generates an alarm signal.

An orifice pack is provided for delivering pressurized air to a compressor bleed valve of a gas turbine engine. The orifice pack has a diffusion chamber in serial flow communication with a tapering passage and a first outlet passage for venting a first portion of the pressurized air from the diffusion chamber. A second outlet passage branches off from the diffusion chamber at an axial location between the inlet and the tapering passage. The second outlet passage is fluidly connected to the compressor bleed valve for directing a second portion of the pressurized air from the diffusion chamber to the compressor bleed valve.

A valve assembly for a turbine engine includes a valve arranged in an air flow path. The valve has a shaft. The valve is movable between an open position and a closed position. An electric actuator is coupled to the shaft and is configured to move the valve between the open position and the closed position. A thermal barrier is arranged between the valve and the electric actuator.

An air pump is provided, the air pump comprising: an air pump housing; a first check valve; a main air pump; an airway switching device; an air-supplementing pump; an air pressure sensor; and a control device. The control device is electrically connected to the main air pump, the airway switching device, the air-supplementing pump, and the air pressure sensor, and is configured to: send a main air pump stop signal based on the air pressure sensor detecting a threshold pressure in the inflatable body during operation of the main air pump; and send an air-supplementing pump operation signal based on the air pressure sensor detecting a pressure lower than the threshold pressure in the inflatable body when the main air pump is not in operation.