AN INTERNAL COMBUSTION ENGINE SYSTEM

An internal combustion engine system includes an internal combustion engine having a cylinder, an air intake system to feed air to the cylinder, an exhaust gas system to feed exhaust gas away from the cylinder, a turbocharger including a turbocharger turbine operatively connected to a turbocharger compressor, wherein the air intake system is arranged to feed intake air via the turbocharger compressor and wherein the exhaust gas system is arranged to feed exhaust gas via the turbocharger turbine so as to drive the turbocharger compressor, and wherein the internal combustion engine system further includes a positive displacement machine arranged in the exhaust gas system downstream of the turbocharger turbine. The internal combustion engine system further includes a variable drive unit to drive the positive displacement machine. The internal combustion engine system controls the drive unit so as to control a flow of exhaust gas through the positive displacement machine.