Electrically heated catalytic converter for an engine

Abstract

An electrically heated catalytic converter having a substrate for a catalyst which is formed as a scroll-like cylindrical laminated assembly, a rod like metal center electrode connected to the laminated assembly, and a casing accommodating the laminated assembly which also acts as an outer electrode. The center electrode extends from the laminated assembly along the central axis, bends towards the wall of the casing and penetrates the casing. The center electrode is fixed to the casing via an insulating material at the point where it penetrates the casing. Four buffer members are interposed between the laminated assembly and the casing, each of buffer members being made of a metal plate, one end of the respective buffer members being fixed to the casing at the portion near the penetration point of the center electrode, the other end of the respective buffer members being fixed to the outside of the laminated assembly. During the operation of the engine, the laminated assembly is displaced by the thermal expansion of the center electrode. In the present invention, thermal expansions also occurs in each of the buffer members. Since the ends of the buffer members are fixed near to the penetration point at which the center electrode is fixed to the casing, the amounts of the displacements of the other ends of the buffer members where the buffer members are fixed to the laminated assembly are equal to the displacement of the laminated assembly caused by the thermal expansion of the center electrode. Therefore, the displacement of the laminated assembly is not hindered by the buffer members. Thus, the buffer members support the laminated assembly without causing excessive stress in the laminated assembly.