Patent ID: 6981375

Claim:
An internal combustion engine with a plurality of cylinders, the engine including an intake manifold and an exhaust manifold, the engine being operated such that the intake manifold pressure generally exceeds the exhaust manifold pressure, the engine further comprising: a low pressure turbocharger including a turbine driven by the exhaust gases and a compressor having an inlet receiving fresh intake air and an outlet providing low pressure charge air; a high pressure turbocharger including a turbine driven by the exhaust gases and a compressor having an inlet receiving the low pressure charge air and an outlet providing high pressure charge air to the intake manifold; an exhaust gas recirculation (EGR) system passively routing a portion of the exhaust gases to the high pressure turbocharger compressor inlet; and wherein a compression ratio of the low pressure turbocharger is greater than a compression ratio of the high pressure turbocharger.