CONTROL DEVICE FOR AN ELECTRICALLY HEATED CATALYST, AND ELECTRODE DETERIORATION DEGREE ESTIMATION DEVICE FOR AN ELECTRICALLY HEATED CATALYST

摘要

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.

主权项

1. A control device for an electrically heated catalyst which is arranged in an exhaust passage of an internal combustion engine, and which is provided with a heat generation element 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 wherein a control unit is provided which decreases 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.