Apparatus for and method of controlling temperature of exhaust gas sensor, and recording medium storing program for controlling temperature of exhaust gas sensor

Abstract

The temperature of an exhaust gas flowing through an exhaust passageis estimated or detected, and the temperature of an active element of an exhaust gas sensor. (Osensor) is controlled at a predetermined target temperature by a heater using the estimated or detected temperature of the exhaust gas. For estimating the temperature of the exhaust gas in the vicinity of the exhaust gas sensor, the exhaust passageextending up to the exhaust gas sensoris divided into a plurality of partial exhaust passagewaysthrough, the temperatures of the exhaust gas in the partial exhaust passagewaysthroughare estimated successively from an exhaust portof an engine. The temperature of the exhaust gas is estimated according to an algorithm which takes into account a heat transfer between the exhaust gas and passage-defining memberswhich define the exhaust passageand a heat radiation from the passage-defining members into the atmosphere. A control input that is applied to the heater includes at least a component depending on the temperature of the active element of the exhaust gas sensorand a component depending on the temperature of the exhaust gas. Even if the temperature of the exhaust gas changes, the temperature of the active element of the exhaust gas sensorcan be controlled stably at the desired temperature.