The invention relates to a method for modeling a compressor intake temperature and/or a compressor discharge temperature of a compressor taking into account a compressor surge, wherein the method comprises: Identifying a pressure gradient across the compressor Identifying a mass flow gradient across the compressor Establishing that the compressor surge is present when the pressure gradient exceeds an upper pressure gradient limit and the mass flow gradient falls below a lower mass flow gradient limit; and Identifying the compressor intake temperature with a temperature correction factor that is dependent on the compressor surge and/or identifying the compressor discharge temperature on the basis of a corrected compressor discharge pressure that is dependent on the compressor surge.

An object is to provide an engine system including an intake bypass device whereby it is possible to expand the operation range of a compressor without causing the output of a turbine to become insufficient. An engine system includes an intake bypass device including a bypass channel connecting a downstream side of a compressor of a turbocharger in an intake channel and an upstream side of a turbine of the turbocharger in an exhaust channel, a bypass valve disposed in the bypass channel and configured to control a flow of compressed intake air in the bypass channel, and a heating unit for heating the compressed intake air flowing through the bypass channel.

A centrifugal compressor for a turbocharger includes an inlet-adjustment mechanism in an air inlet for the compressor, operable to move between an open position and a closed position in the air inlet. The inlet-adjustment mechanism includes an axially elongated ring. In the open position, the radially outer surface of the ring is spaced from a tapering inner surface of the air inlet so that air can flow in an annular passage between the tapering surface and the ring. In the closed position, the ring abuts the tapering surface to close off the annular passage, whereby the effective inlet diameter is then defined by the inner diameter of the ring at its trailing edge. Movement of the inlet-adjustment mechanism from the open position to the closed position is effective to shift the compressor's surge line to lower flow rates.

The turbocharged engine control device comprises a basic target torque-deciding part for deciding a basic target torque based on a driving state of a vehicle including an accelerator pedal operation state; a torque reduction amount-deciding part for deciding a torque reduction amount based on a driving state of the vehicle other than the accelerator pedal operation state; a final target torque-deciding part for deciding a final target torque based on the decided basic target torque and the decided torque reduction amount; and an engine output control part for controlling an intake air amount so as to realize a target air amount required for an engine to output the decided final target torque, wherein the engine output control part is operable, when an operating state of the engine falls within a supercharging region, to restrict a reduction in the intake air amount corresponding to a change in the torque reduction amount.

A valve assembly is disclosed, and includes an evacuator and a relief valve. The evacuator includes a suction port that selectively applies a vacuum. The relief valve has an open position and a closed position, and includes an inlet, an outlet, a piston that translates within a chamber, and a pressurized chamber. The piston includes a first end and a second end. The pressurized chamber is fluidly connected to the suction port of the evacuator, and is defined in part by the first end of the piston. The piston translates within the pressurized chamber towards the open position if vacuum is applied to the pressurized chamber.

The present invention relates firstly to a method for operating a compressor powered by an internal combustion engine for compressing air. Furthermore, the invention relates to a compressor, which is suitable for executing the method according to the invention. A first turbocharger for supplying pre-compressed air to the internal combustion engine is disposed in an exhaust flow of the internal combustion engine. Furthermore, a second turbocharger for pre-compression of the air to be compressed by the compressor is disposed in the exhaust flow of the internal combustion engine. The method according to the invention first comprises a step in which a monitoring of a pressure of the pre-compressed air generated by the first turbocharger occurs during an operating state of the compressor. In a further step of the method, a termination of the operating state occurs as soon as the monitored pressure falls below a previously determined value.

An engine system is mounted on a vehicle and includes an engine and a turbocharger. The engine system control apparatus includes: a driving state identifier that identifies a driving state of the vehicle from a plurality of driving states; a surge determiner that determines whether a surge condition as a condition under which a surge noise is generated is satisfied, based on the identified driving state of the vehicle and an operating state of the engine; and a variable nozzle controller that controls, based on the identified driving state of the vehicle and the operating state of the engine, an opening degree of a variable nozzle of the turbocharger to be varied in an open direction, upon determination by the surge determiner that the surge condition is satisfied.

Systems and methods for operating a compressor and a compressor recirculation valve of a turbocharged engine to avoid the possibility of compressor surge are presented. The systems and methods position the compressor recirculation valve responsive to a compressor surge line that is based on two other compressor surge lines that may be a function of compressor pressure ratio and compressor flow.

A method for controlling and/or regulating an exhaust gas turbocharger of an internal combustion engine, the exhaust gas turbocharger being protected against an exceeding of a maximum rotational speed, an actual boost pressure being compared with a setpoint boost pressure. The risk of a maximum rotational speed of the exhaust gas turbocharger being exceeded is prevented in that a manipulated variable assigned to the exhaust gas turbocharger is compared with a manipulated variable limit characteristic and is limited, if necessary, the manipulated variable limit characteristic having a time-limited, first portion and a chronologically subsequent, second portion following a change in the setpoint boost pressure, the first portion ending after a predetermined target time, the second portion of the manipulated variable limit characteristic being reduced with respect to the first portion in such a way that the maximum rotational speed of the exhaust gas turbocharger is not reached.

A method for controlling a boost pressure of an engine, which includes a charging device including a compressor and a compressor bypass, the compressor bypass including a blow off valve for opening and closing the compressor bypass. A boost pressure control uses an actual boost pressure and a setpoint boost pressure as input parameters. A first compressor pressure ratio is ascertained based on a limit line from a compressor characteristic map and an engine absorption characteristic for the engine. A second compressor pressure ratio is ascertained based on the limit line, a mass flow, and a throttle characteristic curve for the blow off valve. A maximum permissible compression ratio for the compressor is ascertained from the first and second compressor pressure ratios. A maximum permissible boost pressure is ascertained as a function of the maximum permissible compression ratio. The boost pressure control is limited to the maximum permissible boost pressure.