US Patent 7661265 Exhaust gas system for an internal combustion engine

An exhaust gas system for an internal combustion engine, comprising an oxidation catalytic converter disposed in a first exhaust gas manifold section with which the exhaust gas outlets of a first portion of the cylinders communicate, and a hydrolysis catalytic converter disposed in a second exhaust gas manifold section with which the exhaust gas outlets of the remaining portion of the cylinders communicate. The hydrolysis catalytic converter, together with the oxidation catalytic converter that annularly surrounds it, are installed in a common housing. A tubular portion of the second exhaust gas manifold section extends into the housing and accommodates the hydrolysis catalytic converter in its end portion. A tubular portion of a first exhaust gas manifold section surrounds the tubular portion of the second exhaust gas manifold section, resulting in an annular in-flow chamber for the oxidation catalytic converter that simultaneously serves as a heating chamber. A reduction agent, from which ammonia can be produced by the hydrolysis catalytic converter, can be introduced by a nozzle into the tubular portion of the second exhaust gas manifold section upstream of the hydrolysis converter.