Patent ID: 7805928

Claim:
A system for controlling an exhaust gas sensor, the exhaust gas sensor including a heater and being disposed in an exhaust pipe of an internal combustion engine, the system comprising: a first means for preventing water condensation in the exhaust pipe at an upstream portion of the exhaust gas sensor by retarding ignition timing of the engine for a predetermined period after the engine is started to thereby elevate exhaust gas temperature in the exhaust pipe; a second means for heating a catalyzer for cleaning the exhaust gas by retarding ignition timing of the engine, a third means for determining a larger of (i) an amount of ignition timing retardation for preventing water condensation and (ii) an amount of ignition timing retardation for heating the catalyzer, and selecting and setting the determined larger amount as a final amount of ignition timing retardation, the amount of ignition timing retardation for preventing water condensation is calculated based on an engine speed and an amount of intake air, and the first means retards the ignition timing until an accumulated amount of intake air exceeds a criterion amount, an accumulated temperature in an exhaust gas exceeds a criterion accumulated temperature, or an exhaust port temperature exceeds a criterion exhaust port temperature.