Patent ID: 6120677
Filing Date: 2000-09-19
Classification: F02D,G01N

Abstract:
A method of controlling a temperature of a wide-range oxygen sensor, wherein the oxygen sensor includes two cells each having an oxygen ion conductive solid electrolytic body and two porous electrodes disposed on opposite sides of the oxygen ion conductive solid electrolytic body, respectively, the two cells being disposed so as to oppose each other with a gap therebetween, one of the cells serving as a pump cell for pumping oxygen out of or into the gap, the other of the cells serving as an electromotive force cell for producing a voltage according to a difference in oxygen content between an oxygen reference chamber and the gap, and the temperature of the two cells being controlled by using a heater, the method comprising:applying a constant current or voltage for measurement of a resistance value to the electromotive force cell;measuring the resistance value of the electromotive force cell within a period of time ranging from 1 .mu.s to 10 ms after application of said current or voltage for measurement of resistance value so that a measured resistance value of the electromotive force cell is free of a resistance component at an interface between each of the porous electrodes and the oxygen ion conductive solid electrolytic body; andcontrolling the heater such that the measured resistance value of the electromotive force cell is maintained constant.