Patent ID: 8327625

Claim:
A method for regenerating soot filters in an exhaust system of a lean-burn engine, said method comprising: exposing a first exhaust gas stream to a first soot filter, wherein said first soot filter is located in a first exhaust line and the first exhaust line receives the first exhaust gas stream from a first plurality of cylinders; exposing a second exhaust gas stream to a second soot filter, wherein said second soot filter is located in a second exhaust line and the second exhaust line receives the second exhaust gas stream from a second plurality of cylinders; combining the first exhaust gas stream and the second exhaust gas stream downstream of the first soot filter and downstream of the second soot filter to form a mixed exhaust gas flow in a common exhaust line, wherein identical exhaust-gas conditions prevail in both exhaust lines during a normal operation of the engine, and each of the soot filters filter out soot that is generated by the engine; exposing the mixed exhaust gas flow to a denitrogenization catalytic converter; and regenerating the first soot filter and the second soot filter at different times by means of an increase in an exhaust-gas temperature in an associated exhaust line to a soot ignition temperature while normal exhaust-gas conditions continue to prevail in the other exhaust line, such that the common exhaust line has a temperature between an exhaust-gas temperature of normal operation and an exhaust-gas temperature during regeneration wherein the mixed exhaust gas flow contains nitrogen oxides that during a lean phase are stored on the denitrogenization catalytic converter and during a rich phase are released by the denitrogenization catalytic converter and are converted to nitrogen.