Patent ID: 7513104

Claim:
A diagnostic apparatus for an internal combustion engine, comprising: an exhaust purification section comprising: an exhaust purifier disposed in an exhaust passage of the internal combustion engine, for purifying an exhaust emission; and a purifier activation section configured to control engine operating parameters of the internal combustion engine to promote activation of the exhaust purifier during the internal combustion engine being cold; and a control unit configured to perform the following: determining a total exhaust heat quantity as a quantity of heat entering the exhaust purifier during the internal combustion engine being cold; determining a state of the exhaust purifier in accordance with the total exhaust heat quantity, wherein the state of the exhaust purifier includes a purifier residual emission ratio as a proportion of a quantity of the exhaust emission which passes through the exhaust purifier without being purified; determining a total purifier out emission quantity as a quantity of the exhaust emission exiting the exhaust purifier during the internal combustion engine being cold, in accordance with the state of the exhaust purifier; and determining normality of the exhaust purification section in accordance with the total purifier out emission quantity.