Patent attributes
An oxygen concentration sensor including the sensor element for detecting oxygen concentration in the exhaust gas and the heater for heating the sensor element is installed at the location downstream of a DPF. An ECU controls power supply to the heater to make the sensor element at a predetermined active state. The ECU calculates heat data corresponding to a heat budget in the exhaust pipe in close proximity to the sensor location part after the engine startup, based upon an operating condition of the engine and a driving condition of a vehicle and also makes a determination as to dryness inside the exhaust pipe based upon the heat data. In addition, the power supply to the heater is controlled based upon the result of the dryness determination.
