Patent ID: 8826643

Claim:
An exhaust gas purifying device for an internal combustion engine, comprising: an electrically heated catalyst which is provided on an exhaust passage of the internal combustion engine, which purifies the exhaust gas drawn to the exhaust passage, and which is warmed by electrification; an electrification characteristic setting unit which set an electrification characteristic indicating a characteristic of an electrification resistance value in the electrically heated catalyst, in accordance with an electrification condition at a time of starting the electrification of the electrically heated catalyst; a unit which performs an abnormality determination or an electrification control for the electrically heated catalyst, based on the electrification characteristic set by the electrification characteristic setting unit; a permissible resistance range setting unit which sets a permissible resistance range for determining an actual electrification characteristic of the electrically heated catalyst, based on the electrification characteristic set by the electrification characteristic setting unit; and an abnormal electrification determining unit which obtains the actual electrification characteristic of the electrically heated catalyst, and determines the abnormal electrification of the electrically heated catalyst when the actual electrification characteristic becomes out of the permissible resistance range, wherein the permissible resistance range setting unit sets the permissible resistance range in accordance with the electrification condition to the electrically heated catalyst at the time of starting the electrification.