System using supplemental compressor for EGR

A system for driving an EGR stream for an engine includes an exhaust gas turbine, a main compressor and a supplemental EGR compressor. The turbine drives the main compressor to pressurize intake air and drives the supplemental EGR compressor to pressurize an EGR exhaust gas stream to be introduced into the intake air system. A supplemental EGR compressor takes suction of exhaust gas downstream from the turbine. A three-way valve proportions exhaust gas between the engine exhaust gas discharge conduit and the suction of the supplemental EGR compressor. The turbine drives a shaft and the main compressor and the supplemental EGR compressor are driven by having corresponding compressor wheels fixed onto the common shaft.