Pressure balanced turbocharger rotating seal
A pressure balanced turbocharger rotating seal is provided by two piston rings mounted on the shaft of the turbocharger, one of the rings engaging a circumferential surface of the shaft bore in the center housing and the second ring engaging a circumferential surface of the shaft bore in the turbine wheel shroud, with a passage for introducing pressurizing gas intermediate the two rings, the passage including a circumferential channel in the inner face of the turbine wheel shroud, and a compression seal engaged between the center housing and turbine wheel shroud outboard of the channel.