NOX SENSOR DIAGNOSIS DEVICE AND SCR SYSTEM

摘要

Provided are a NOX sensor diagnosis device which can diagnose the validity of a NOX sensor in view of environment conditions and prevent an erroneous diagnosis, and a selective catalytic reduction (SCR) system. A NOX sensor diagnosis device is provided in an exhaust pipe (102) of an engine (E), and diagnoses a NOX sensor (110) to detect the density of NOX in an exhaust gas. The NOX sensor diagnosis device is provided with a diagnosis prohibition determination unit (4) for prohibiting diagnosis of the NOX sensor (110) during reproduction of a diesel particulate filter (DPF), during operation of power take off (PTO), or during operation of an exhaust brake.