Honeycomb heater

Abstract

A heating element for heating fluid flowing therethrough includes: a honeycomb structure having a periphery and two ends, including a plurality of passages which are defined by partition walls and extend in an axial direction between the ends, the honeycomb structure being composed of an electrically conductive material; and a pair of electrodes for applying electric current to the honeycomb structure so as to generate heat; wherein a maximum length of linear portions of the partition walls is up to 10 mm as viewed in a cross-section of the honeycomb structure taken perpendicular to the axial direction, and a number of the passages in one square inch ranges from 50 to 800 as viewed in the cross-section of the honeycomb structure, thereby insuring improved thermal shock resistance and purification efficiency. The partition walls are less prone to deformation and crack formation due to thermal stress.

Dependencies are inferred from the claim text.