Systems and methods for controlling turbocharger operation by maintaining a virtual turbocharger speed calculation using airflow parameters in the context of an engine. An example uses a turbocharger speed estimator, an energy observer, and an energy controller. Optimization of turbocharger speed control, including avoidance of overspeed, while reducing wastegate actuation, can be achieved using a predictive control algorithm.

The invention concerns a method for controlling a compression release brake mechanism in an combustion engine comprising an air inlet system and an exhaust manifold connected to a turbocharger provided with a variable turbine geometry (VTG) turbine, said exhaust manifold further comprising an exhaust gas recirculation (EGR) channel for recirculation of exhaust gas towards the air inlet system, wherein said turbine is further connected to a back pressure valve (BPV) provided in an exhaust channel, the method comprising determining a desired exhaust manifold gas pressure level on the basis of a measured engine speed and a desired braking torque; continuously monitoring a set of control parameters, including at least two of cylinder pressure, exhaust manifold pressure, turbine speed and turbine expansion ratio; controlling said BPV and said VTG by said control parameters, to drive one of the control parameters to a set maximum level; and controlling the EGR by said control parameters in a closed loop to allow exhaust gas to recirculate towards the air inlet system while driving a second of the set of control parameters to a set maximum level.

A recirculation system for a power system is disclosed. The recirculation system may determine, according to a sequence for individually activating a plurality of turbochargers of an engine, that a designated turbocharger of the plurality of turbochargers is to be activated. The recirculation system may cause a recirculation valve of a recirculation line to open to increase an airflow between an intake manifold and a compressor of the designated turbocharger.

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.

An intake system for use with an internal combustion engine having one or more cylinders. The intake system including a compressor assembly having an inlet and an outlet, and where the outlet is configured to be open to and in fluid communication with at least one of the one or more cylinders. The intake system also includes a passageway extending between and in fluid communication with the inlet and the outlet and configured to direct a first flow of gasses and a controller in operable communication with the compressor assembly. Where the intake system is operable in a first mode in which the majority of gasses of the first flow of gasses flow through the passageway toward the outlet, and a second mode in which the majority of gasses of the first flow of gasses flow through the passageway toward the inlet.

New and/or alternative approaches to performance control in an engine system having a compressor configured to receive torque from each of a turbine placed in an exhaust output of an engine and an electric motor. A control unit for the electric motor, referred to as an ETurbo controller, is provided with each of a speed control signal and a torque control signal from an engine control unit. The ETurbo controller is configured to use the torque control signal and speed control signal to operate the electric motor without causing the compressor to exceed a speed boundary.

Systems, methods, and computer-readable storage media for emulating a turbocharger speed sensor of a turbocharger in an engine. A processor executing the method can receive data from a plurality of sensors in the engine, wherein the data includes: an exhaust manifold pressure of the engine; an exhaust mass flow of the engine; and an injection angle of fuel in the engine. The processor enters the data as inputs into an artificial neural network, where the artificial neural network is trained to receive the inputs and output a speed of the turbocharger of the engine, then receives an output from the artificial neural network which is the speed of the turbocharger.

Based on entry/exit pressures of a compressor detected by atmospheric/boost pressure sensors, a pressure ratio of compressor is calculated. Based on mass flow rate and entry temperature of intake air detected by intake air flow-rate/temperature sensors and entry pressure, a volumetric flow rate of intake air is calculated in environmental condition at a detection time using gas state equation, and is corrected into a volumetric flow rate under standard environmental condition thorough multiplication by a corrective coefficient based on entry temperature of intake air. Based on the corrected value and the calculated pressure ratio, a rotational frequency of compressor under standard environmental condition is read out in light of operating characteristic diagram for the compressor. Read-out rotational frequency is corrected into actual rotational frequency of the compressor through multiplication by a corrective coefficient based on entry temperature of intake air, which is determined as rotational frequency of turbocharger.

Methods and systems are provided for controlling boost pressure in a staged engine system comprising a turbocharger and an upstream electric supercharger based on altitude. During vehicle operation at higher altitudes, where vacuum availability for wastegate actuation is limited, boost pressure may be provided by operating the electric supercharger more aggressively. The wastegate may be used for boost control once the vacuum reserve is replenished.

Methods and systems are provided for controlling boost pressure in a staged engine system comprising a turbocharger and an upstream electric supercharger. In one example, a method may include coordinating the operation of the electric supercharger and an electric supercharger bypass valve and to open the electric supercharger bypass valve to reduce the extent and duration of electric supercharger overboost.