Turbocharger with exhaust gas recirculation

An internal combustion engine, comprising:

• an exhaust manifold;
• an intake manifold;
• and
• a turbocharger including:
• a rotatable shaft;
• a turbine including a turbine wheel carried by said shaft;
• a multi-stage compressor including a first compressor wheel carried by said shaft, an axially extending first inlet associated with said first compressor wheel, a radially extending first outlet associated with said first compressor wheel, a second compressor wheel carried by said shaft, a second inlet associated with said second compressor wheel, and a radially extending second outlet associated with said second compressor wheel, said second outlet being in fluid communication with said intake manifold;
• an interstage duct fluidly interconnecting in series said first outlet associated with said first compressor wheel with said second inlet associated with said second compressor wheel;
• an exhaust gas recirculation duct fluidly interconnecting said interstage duct with at least one of said turbine and said exhaust manifold;
• and
• a valve positioned within said exhaust gas recirculation duct.

A method of operating a turbocharger in an internal combustion engine, comprising the steps of:

• providing a turbine including a turbine wheel carried by said shaft;
• providing a multi-stage compressor including a first compressor wheel carried by said shaft, an axially extending first inlet associated with said first compressor wheel, a radially extending first outlet associated with said first compressor wheel, a second compressor wheel carried by said shaft, an axially extending second inlet associated with said second compressor wheel, and a radially extending second outlet associated with said second compressor wheel;
• fluidly interconnecting in series said first outlet associated with said first compressor wheel with said second inlet associated with said second compressor wheel using an interstage duct;
• fluidly interconnecting said turbine with said interstage duct using an exhaust gas recirculation duct;
• positioning a valve within said exhaust gas recirculation duct;
• rotating said turbine wheel, said first compressor wheel and said second compressor wheel carried by said shaft;
• and
• selectively actuating said valve to recirculate exhaust gas from said turbine to said interstage duct.