Abstract: A method is provided for measuring exhaust gas recirculation (EGR) flow in. an engine system wherein turbo speed of a turbocharger, inlet pressure upstream of a compressor, boost pressure upstream of an engine, and engine intake temperature upstream of the engine are measured. Air mass flow into the engine system is calculated as a function of the turbo speed, inlet pressure, and boost pressure, exhaust mass flow is calculated as a function of the boost pressure, the engine intake temperature, volumetric efficiency of the engine, and engine size, and EGR flow is determined, by subtracting air mass flow from exhaust mass flow. A method for controlling emissions from an engine system, and an. engine system are also provided.

Abstract: A method is provided for measuring exhaust gas recirculation (EGR) flow in. an engine system wherein turbo speed of a turbocharger, inlet pressure upstream of a compressor, boost pressure upstream of an engine, and engine intake temperature upstream of the engine are measured. Air mass flow into the engine system is calculated as a function of the turbo speed, inlet pressure, and boost pressure, exhaust mass flow is calculated as a function of the boost pressure, the engine intake temperature, volumetric efficiency of the engine, and engine size, and EGR flow is determined, by subtracting air mass flow from exhaust mass flow. A method for controlling emissions from an engine system, and an. engine system are also provided.

Abstract: A turbocharger includes a turbine comprising a scroll passage including at least first and second portions, a gas outlet extending axially from the scroll passage, a turbine wheel including one or more blades disposed in the gas outlet, and structure for establishing a bypass flow between the first and second portions of the scroll passage or for altering gas flow through the turbine. A method for adjusting exhaust gas temperature is also provided.

Abstract: A turbocharger includes a turbine comprising a scroll passage including at least first and second portions, a gas outlet extending axially from the scroll passage, a turbine wheel including one or more blades disposed in the gas outlet, and structure for establishing a bypass flow between the first and second portions of the scroll passage or for altering gas flow through the turbine. A method for adjusting exhaust gas temperature is also provided.

Abstract: A method is provided for controlling varnish build-up in a variable geometry turbine (VGT) of a diesel engine turbocharger. According to the method, it is determined whether an operation parameter is at a level established for initiating a varnish build-up control sequence. Upon determining that the operation parameter is at the established level, the varnish build-up control sequence is initiated. The sequence comprises increasing exhaust temperature upstream of the VGT to a first exhaust temperature, and changing an opening size of a VGT nozzle between a smaller and a larger opening size in association with increasing the exhaust temperature to the first exhaust temperature. A diesel engine arrangement is also provided.