PAKOKAASUJÄRJESTELMÄ JA MENETELMÄ SELEKTIIVISTÄ KATALYYTTISTÄ PELKISTYSTÄ VARTEN

An exhaust system for an internal combustion engine (1) comprising a high-pressure turbocharger (2), a low-pressure turbocharger (3) comprising a turbine (3b) being arranged downstream from the turbine (2b) of the high-pressure turbocharger (2), means (7a, 7b) for connecting the turbine inlet (2c) of the high-pressure turbocharger (2) to a group of cylinders (15) of the engine (1), a catalytic converter (4), and means (5) for introducing reducing agent into the exhaust system. The exhaust system further comprises means (7c) for connecting the turbine outlet (2c) of the high-pressure turbo-charger (2) to an inlet (4b) of the catalytic converter (4), and means (7d) for connecting an outlet (4c) of the catalytic converter (4) to the turbine inlet (3c) of the low-pressure turbocharger (3). The means (5) for introducing reducing agent into the exhaust system are arranged upstream from the turbine (2b) of the high-pressure turbocharger (2).The invention also concerns a method for selective catalytic reduction.