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

Abstract

The present invention is intended to provide a technique which is capable of contributing to the suppression of the deterioration of surface electrodes in an electrically heated catalyst. The electrically heated catalyst according to the invention is provided with a heat generation element to heat a catalyst, and a pair of electrodes to supply electricity to the heat generation element. Each of the pair of electrodes has a surface electrode which spreads along a surface of the heat generation element, and the surface electrodes are arranged in opposition to each other with the heat generation element being sandwiched therebetween. Then, 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 the surface electrodes exceeds a predetermined temperature difference, an electric power supplied to the heat generation element is decreased, and an amount of heat supplied to the EHC by an exhaust gas is increased, as compared with when the frequency is small.