Turbocharged internal combustion engine with a portion of exhaust gases from engine bypassing turbocharger turbine for rapid catalyst light-off without waste gate performance penalty in turbine

Abstract

An engine system includes an internal combustion engine, at least one turbocharger, and a catalytic treatment device. The engine includes an exhaust manifold system having a main exhaust manifold and a bypass exhaust manifold. A partial-engine bypass valve system is positioned between the engine and the exhaust manifold system. The bypass valve system when placed in a non-bypass position directs all of the engine exhaust gases to the turbine wheel of the turbocharger, and after passing through the turbine wheel the gases proceed to the catalytic device. In a bypass position of the bypass valve system, a bypass portion of the total exhaust gases is made to bypass the turbine wheel and proceed to the catalytic device, while the remainder first passes through the turbine wheel before going to the catalytic device.