Patent ID: 7895824

Claim:
A diagnosis apparatus for a secondary air supply system for an internal combustion engine having an exhaust passage, which connects with an exhaust gas purification apparatus, the secondary air supply system comprising: a secondary air supply passage that connects with the exhaust passage; an air pump for supplying secondary air to an upstream of the exhaust gas purification apparatus in the exhaust passage of the internal combustion engine through the secondary air supply passage; and a detecting unit for detecting a detection object of secondary air, the diagnosis apparatus comprising: a diagnosis unit for performing a diagnosis operation to evaluate an abnormity of the secondary air supply system in accordance with a detection result of the detecting unit; an obtaining unit for obtaining information of temperature of the air pump; and a changing unit for changing the diagnosis operation of the diagnosis unit in accordance with the information of the temperature of the air pump; the secondary air supply system further comprising: a battery for supplying electricity to the air pump; a voltage detecting unit for detecting voltage of the battery; and a load detecting unit for detecting load applied to the air pump, wherein the obtaining unit includes a calculating unit for calculating the temperature of the air pump in accordance with at least one of a detection result of the voltage detecting unit and a detection result of the load detecting unit, the calculating unit is adapted to setting an initial value of the temperature of the air pump, the calculating unit is adapted to calculating a variation in the temperature of the air pump in a period, which is between a previous timing of a calculation of the temperature of the air pump and a present timing of the calculation of the temperature of the air pump, in accordance with at least one of the voltage of the battery and the load applied to the air pump, after setting the initial value of the temperature of the air pump, and the calculating unit is adapted to calculating the temperature of the air pump by adding the variation to the temperature of the air pump, which is calculated on the previous timing of the calculation.