Patent ID: 7370644

Claim:
An EGR control apparatus for an internal combustion engine having a suction passage, an exhaust passage, and an EGR passage, the EGR passage connecting the suction passage with exhaust passage, the EGR control apparatus comprising: an EGR valve that is disposed in the EGR passage for regulating a flow rate of EGR gas flowing from the exhaust passage to the suction passage through the EGR passage; and a control unit that includes a removal unit, which is adapted to executing a foreign-matter removal operation by controlling the EGR valve in order to remove foreign matters deposited on an inwall surface of the EGR passage, wherein the control unit further includes a deposition detecting unit that detects at least one of a deposition intensity of foreign matters deposited on the inwall surface of the EGR passage and a deposition quantity of foreign matters deposited on the inwall surface of the EGR passage, and the removal unit controls the EGR valve in accordance with the at least one of the deposition intensity and the deposition quantity; wherein the deposition detecting unit estimates at least one of the flow rate of EGR gas and a foreign-matter concentration in EGR gas after the removal unit executes a previous foreign-matter removal operation, the deposition detecting unit calculates a foreign-matter accumulation index in accordance with the at least one of the flow rate of EGR gas and the foreign-matter concentration in EGR gas, and the deposition detecting unit detects at least one of the deposition intensity and the deposition quantity in accordance with the foreign-matter accumulation index.