Abstract: An exhaust gas after treatment system includes a diesel particulate filter unit arranged downstream of a diesel engine, a NO2 reduction catalyst arranged downstream of said diesel particulate filter, a selective catalytic reduction (SCR) arrangement arranged downstream of said NO2 reduction catalyst, a first injector for feeding reducing agent into the exhaust gas arranged downstream said particulate filter and upstream said NO2 reduction catalyst, a second injector for feeding reducing agent into the exhaust gas arranged downstream said NO2 reduction catalyst and upstream said selective catalytic reduction (SCR) arrangement. An exhaust gas after treatment method is also provided.

Abstract: Method and arrangement for regulating the rotational speed of a crankshaft included in an internal combustion engine during a gear changing process of a gearbox connected to the internal combustion engine. The arrangement includes a compressor mounted in connection with the air inlet of the internal combustion engine. A transmission having a variable gear ratio is located between the crankshaft and a driving shaft arranged in connection with the compressor, and a control unit is arranged to control the gear ratio between the crankshaft and the compressor. When changing from a higher to lower gear, the control unit is arranged to control the gear ratio between crankshaft and compressor so that the gear ratio between these components is reduced, and wherein moment of inertia is transferred from compressor to crankshaft resulting in an acceleration of the crankshaft.