Method for operating exhaust gas purification systems

摘要

The invention relates to a method for purifying exhaust gas in vehicles with internal combustion engines. The method is characterized in that exhaust gas coming from the engine (1) is then led past the catalyst(s) (4) near the engine when the engine of the vehicle is not performing positive work.

主权项

1. A method for the catalytic purification of the exhaust gas from internal combustion engines by means of a catalyst system having a main exhaust section containing at least one first close-coupled catalyst and a secondary exhaust section as well as a switchover device for switching the exhaust flow to the main exhaust section and/or the secondary exhaust section, comprising
determining whether or not the engine is performing positive work and passing the exhaust gas via the main exhaust section when the engine is determined to be performing positive work; and passing the exhaust gas via the secondary exhaust section when the engine is determined to be not performing any positive work and a certain exhaust gas temperature, which is less than or equal to the light-off temperature of the catalyst, is undershot or an exhaust gas temperature of 600° C. is overshot.