Turbocharged engine with pressurized gas recirculation

In an internal combustion engine having a plurality of piston-containing cylinders each defining a combustion chamber, intake manifold means communicating with said combustion chambers, an intake conduit communicating with said intake manifold means for supplying air thereto, an exhaust manifold communicating with said combustion chambers for receiving therefrom the hot exhaust gases, and first turbocharger means for pressurizing the air supplied to said intake manifold means, said first turbocharger means including a rotatable turbine section drivingly connected to and rotatably driving a compressor section, said compressor section being associated with said intake conduit for pressurizing the air which is supplied to said intake manifold means, and a first exhaust conduit providing communication between said exhaust manifold means and said turbine section for rotatably driving said turbine section by the hot exhaust gases which flow through said first exhaust conduit, the improvement comprising second turbocharger means for pressurizing and supplying at least a part of the hot exhaust gases to said intake manifold means, said second turbocharger means including a rotatable turbine part drivingly connected to a rotatable compressor part, a second exhaust conduit communicating between said exhaust manifold means and said turbine part for supplying at least a part of the hot exhaust gases to said turbine part for rotatably driving same, intermediate passage means connected between the discharge of said turbine section and the inlet of said compressor part for supplying the exhaust gases from said first turbocharger means to the compressor part of said second turbocharger means for effecting pressurization of said exhaust gases, and an inlet conduit connected between said compressor part and said intake manifold means for supplying said pressurized exhaust gases from said compressor part to said intake manifold means for mixing with the pressurized air supplied through said intake conduit, the pressurized mixture of exhaust gases and air within said intake manifold means being supplied to said combustion chambers.