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.

A turbocharger (1) includes a turbine wheel (3) driven by exhaust gas, first and second compressor wheels (4, 5) coaxially coupled to the turbine wheel (3) via a shaft member (6), a compressor housing (8) accommodating the first and second compressor wheels (4, 5) and having defined therein a communication passage (17) through which air compressed by the first compressor wheel (4) flows to the second compressor wheel (5), and an electric motor (11) arranged in the communication passage (17) and using the shaft member (6) as a rotation shaft thereof.

A multi-flow exhaust gas turbocharger (101) comprising a turbine (105), a turbine wheel, a first flow (1) and a second flow (2), a bypass line (6) for bypassing the turbine wheel, a bypass valve unit (107) for adjusting the size of a bypass exhaust gas flow through the bypass line (6), and comprising a flow connection unit (108) for adjusting an extent of the connection of exhaust gas flows into the flows (1, 2), characterized in that the bypass valve unit (107) and the flow connection unit (108) can be actuated in a mechanically coupled way by means of a coupling unit (109).

A power-based control system and method for an engine comprising a turbocharger involve obtaining a set of parameters that each affect exhaust gas energy and using the set of parameters to (i) determine a target mass flow into the engine and a target boost for the turbocharger to achieve a torque request, (ii) determine a target power for a compressor of the turbocharger to achieve the target engine mass flow and the target turbocharger boost, (iii) determine a target pressure ratio and a target mass exhaust flow for the turbine of the turbocharger to achieve a target turbine power equal to the target compressor power, and (iv) determine a target position of the wastegate valve to achieve the target turbine pressure ratio and mass exhaust flow, and commanding a wastegate valve to the target position.

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.

According to an embodiment of the present disclosure, the gas engine heat pump includes: an engine including an ignition plug for burning a mixture of air and fuel; a compressor connected to the engine, for compressing refrigerant by an operation of the engine; a mixer for mixing the air and the fuel and supplying the mixture to the engine; a zero governor having a valve, for regulating the amount of fuel supply to the mixer; a throttle valve disposed between the mixer and the engine, for regulating the flow of the mixture entering the engine; and a controller, wherein the controller checks a current number of revolutions of the engine upon receiving a command to stop running the engine, changes a target number of revolutions of the engine so that the current number of revolutions of the engine reaches a first reference number of revolutions, if the current number of revolutions of the engine exceeds the first reference number of revolutions, controls the opening degree of the valve included in the zero governor in response to the change in the target number of revolutions of the engine, and controls the ignition plug to stop igniting if the current number of revolutions of the engine reaches a second reference number of revolutions which is lower than the first reference number of revolutions.

A supercharging system includes a charging device having a turbine and a compressor, the compressor having a high speed shaft; a planetary gear set coupled to the high speed shaft and an electric motor, or generator, via a low speed drive shaft; a clutch unit; a power transmission for connecting a crank shaft of the combustion engine to the drive shaft via the clutch unit; at least one sensor to measure at least one physical parameter of the exhaust gases inside, or after having passed, an exhaust gas catalyzer of the internal combustion engine, the at least one sensor being configured to provide an output signal representing a measured value of the at least one physical parameter; and a system control unit to receive the output signal and to control the speed or effect of the electric motor, or generator, based on the output signal. A method is also disclosed.

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.

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 accelerating an electric supercharger to choke the flow of air to the engine in the event of turbocharger overboost.