Method for checking cross sensitivity of ammonia in SCR catalyst system of diesel engine of motor car, involves recognizing fault of nitrogen oxide sensor in predetermined period according to increase in temperature of catalyst

摘要

The method involves monitoring temperature of a catalyst converter (13). Fault of a nitrogen oxide sensor in a predetermined period is recognized according to increase in temperature of the catalyst around given value if the concentration around a threshold level is not increased by the nitrogen oxide sensor. Two catalyst converters (21) are independently selected from a group consisting of a SCR catalyst converter, a check catalyst converter and an AMOX catalyst converter. Threshold level is determined by using a signal of an ammonia sensor (43). An independent claim is also included for a computer program comprising a set of instructions to perform a method for checking cross sensitivity of ammonia of a nitrogen oxide sensor in a SCR catalyst system of an internal combustion engine.