Method for operating internal-combustion engine of vehicle, involves reducing nitrogen oxide proportion by operation of engine, where gas component in gas is not converted or partly converted based on reduction of nitrogen oxide proportion

摘要

The method involves operating an exhaust gas cleaning device (7) in a normal operation mode with a firing angle. Nitrogen oxide proportion is reduced by temporary operation of an internal-combustion engine (1) with another firing angle if the exhaust gas cleaning device exhibits a loading condition. An exhaust gas component i.e. nitrogen oxide, in the exhaust gas, is not converted or partly converted based on the reduction of the nitrogen oxide proportion. The loading condition of the exhaust gas cleaning device is changed by operating the engine with a lubricate fuel air mixture.