Control device for an electrically heated catalyst, and electrode deterioration degree estimation device for an electrically heated catalyst

A control device for an electrically heated catalyst which is arranged in an exhaust passage of an internal combustion engine, the control device comprising:

• a heat generation element, including a catalyst carrier or structure, and a pair of electrodes that supply electricity to said heat generation element,
• wherein said heat generation element is electrically energized to generate heat so that a catalyst is heated by the generation of heat;
• wherein each of said pair of electrodes has a surface electrode which spreads along a surface of said heat generation element, and said surface electrodes are arranged in opposition to each other with said heat generation element being sandwiched therebetween;
• and
• an electronic control unit is configured to decrease an electric power supplied to said heat generation element, and increases an amount of heat supplied to the electrically heated catalyst by an exhaust gas, when a frequency becomes large in which a condition was satisfied in which a difference in temperature between two points located at a predetermined distance from each other on surfaces or in insides of said surface electrodes exceeds a predetermined temperature difference, as compared with when the frequency is small.