Abnormality detection apparatus for exhaust gas purification apparatus for internal combustion engine

An abnormality detection apparatus of an exhaust gas purification apparatus for an internal combustion engine, having a particulate filter for trapping particulate matters in an exhaust gas disposed at an intermediate part of an exhaust passage by introducing an inlet pressure and an outlet pressure of said particulate filter into a differential pressure sensor through respective piping, detecting a pressure difference at an inlet and an outlet of said particulate filter by using said differential pressure sensor and detecting an amount of the particulate matters accumulated to said particulate filter, said abnormality detection apparatus comprising:

• pulsation measurement means for measuring a magnitude of pulsation of a detection value of said pressure difference;
• and
• abnormality detection means for detecting said piping as being abnormal when the magnitude of pulsation of said pressure difference detection value measured is greater than a predetermined reference value.