Patent ID: 8915708

Claim:
A turbocharger, comprising: a turbine section with a turbine wheel; a compressor section with a compressor wheel; the turbine wheel and the compressor wheel being mounted on a shaft; a housing having a bore with the shaft rotatably mounted in the bore, the housing including a turbine housing with the turbine wheel positioned therein, a compressor housing with the compressor wheel positioned therein, a central bearing housing being positioned between the turbine housing and the compressor housing; a bearing section between the turbine section and the compressor section having a bearing chamber with a bearing assembly therein, the bearing assembly being positioned within the central bearing housing, the bearing assembly rotatably supporting the shaft in the housing, the bearing chamber having a pair of spaced apart opposite sides, a first side being generally adjacent the turbine section and a second side being generally adjacent the compressor section; a lubrication system including a lubricant passage for circulating lubricant within the bearing chamber and to the bearing assembly; and a seal assembly positioned at each side of the bearing chamber, each seal assembly including: a first seal positioned along the shaft adjacent a side of the bearing chamber, a second seal positioned along the shaft and spaced from the first seal, and a recess between the first seal and the second seal, the recess defining an air buffer chamber, the air buffer chamber being in fluid communication with an air supply to provide the air buffer chamber with a supply of pressurized air to create a pressure differential between the bearing chamber and the air buffer chamber that discourages lubricant leakage past the first seal; wherein the shaft includes a remote end, the compressor wheel is positioned between the remote end and the bearing assembly, the remote end of the shaft is rotatably supported by a remote bearing assembly positioned within a remote bearing chamber adjacent the remote end, a first remote seal is positioned along the shaft adjacent the remote end of the shaft and adjacent a side of the remote bearing assembly, a second remote seal is positioned along the shaft and spaced from the first remote seal, and a remote recess between the first remote seal and the second remote seal defines a remote air buffer chamber, the remote air buffer chamber is in fluid communication with a remote air supply to provide the remote air buffer chamber with a supply of pressurized air to create a pressure differential between the remote bearing chamber and the remote air buffer chamber to discourage lubricant leakage past the first remote seal.