Motor vehicle-exhaust gas treatment system for de-nitrification, has stepper motor adjusting valve body relative to valve seat, and spring arranged such that valve body is pressed on valve seat using pressure regulating force

摘要

The system has a catalyzer (18), a carbamide spray nozzle (26) that comprises a carbamide feeding device (28) for feeding carbamide containing solution, and a gas feeding device. The gas feeding device has a pressure reducing valve (38). A valve body is cooperatively arranged with a valve seat. A stepper motor (56) adjusts the valve body relative to the valve seat. A spring i.e. pre-stressing spring, is arranged such that the valve body is pressed on the valve seat using pressure regulating force. An independent claim is also included for a method for operating an exhaust gas treatment system.