Patent ID: 7206714

Claim:
An exhaust gas sensor control device for an exhaust gas sensor that is mounted in an exhaust path of an internal combustion engine, wherein said exhaust gas sensor includes a sensor element that becomes active when an activity temperature is reached, the exhaust gas sensor control device comprising: an impedance detection device for detecting an element impedance of said sensor element; an impedance judgment device for judging whether said element impedance is lowered to an activity judgment value; a received heat amount estimation device for estimating an amount of heat received by said sensor element based on one or more operational parameters related to operation of the internal combustion engine other than said element impedance of said sensor element; a heat amount judgment device for judging whether an activity judgment heat amount is reached in said sensor element based on the amount of heat received by said sensor element; and an activity judgment device for formulating an activity judgment of said exhaust gas sensor when an affirmative judgment is executed either by said impedance judgment device or by said heat amount judgment device.