An improved turbocharged internal combustion engine, having an air intake system that avoids compressor surge. A positive displacement blower is installed on the air intake line between the compressor and the engine cylinders. The blower has variable speed control so that its speed may be modulated. A controller controls the speed of the blower, such that the average pressure ratio across the blower is 1.0 across each engine cycle.

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.

In one aspect, a method for controlling an internal combustion engine system including an exhaust gas recirculation (EGR) valve and a variable-geometry turbocharger (VGT) having a compressor and a turbine includes receiving a plurality of requests for the internal combustion engine system. The method also includes predicting a plurality of expected states of the internal combustion engine system based on the plurality of requests and generating sets of candidate control points for actuating the EGR valve and the VGT based on the plurality of expected states. The method further includes selecting a set of candidate control points that avoids a surge condition of the compressor and based on the selected set of candidate control points, generating commands for actuating the EGR valve and the VGT.

A surge suppression device for suppressing surge in an exhaust turbine-type turbocharger includes: a high-pressure tank configured to accumulate high-pressure gas with a higher pressure than atmospheric pressure; a high-pressure gas injection line connecting the high-pressure tank and an upstream intake passage on an upstream side of a compressor of the turbocharger; an on-off valve configured to open and close the high-pressure gas injection line; and a control device configured to control the on-off valve on the basis of a relationship between a pressure ratio of the compressor of the turbocharger and an intake flow rate.

In one aspect, a method for controlling an internal combustion engine system including an exhaust gas recirculation (EGR) valve and a variable-geometry turbocharger (VGT) having a compressor and a turbine includes receiving a plurality of requests for the internal combustion engine system. The method also includes predicting a plurality of expected states of the internal combustion engine system based on the plurality of requests and generating sets of candidate control points for actuating the EGR valve and the VGT based on the plurality of expected states. The method further includes selecting a set of candidate control points that avoids a surge condition of the compressor and based on the selected set of candidate control points, generating commands for actuating the EGR valve and the VGT.

Methods and systems for controlling a turbocharger associated with an engine. The turbocharger is operated in a region of operation creating potential surge conditions, but surge is avoided by varying the speed of the turbocharger in accordance with speed parameters determined by observing a resonant frequency of surge in the system.

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.

Various methods and systems are provided for a detecting surge of a turbocharger in an engine system. In one example, system includes a turbocharger including a compressor coupled to a turbine and a controller and sensor system configured to detect a surge event of the turbocharger based on at least one of a rate of change of a pressure measured by sensors downstream of the compressor and a measured rate of change of turbine speed, store operational data associated with the surge event in memory of the controller, and determine a performance of the turbocharger based at least in part on one or more of a cumulative number of detected surge events, a magnitude of detected surge events, or associated operational data.

Embodiments for inducing swirl upstream of a compressor are provided. In one example, a method includes during a first condition, flowing exhaust gas from downstream of a turbine to upstream of a compressor via a tangential flow duct of an exhaust gas recirculation (EGR) injector circumferentially surrounding an intake passage upstream of the compressor, and during a second condition, flowing exhaust gas from downstream of the turbine to upstream of the compressor via a radial flow duct of the EGR injector.

Systems and methods are described for operating a turbocharger. A current exhaust manifold pressure is determined based on an engine operating condition. A current operating condition of the turbocharger is determined. A surge correction factor is determined based on the current operating condition of the turbocharger. The current exhaust manifold pressure is adjusted based on the surge correction factor.