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

摘要

The temperature of an exhaust gas flowing through an exhaust passage 3 is estimated or detected, and the temperature of an active element of an exhaust gas sensor 8 (O2 sensor) 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 8, the exhaust passage 3 extending up to the exhaust gas sensor 8 is divided into a plurality of partial exhaust passageways 3a through 3d, the temperatures of the exhaust gas in the partial exhaust passageways 3a through 3d are estimated successively from an exhaust port 2 of an engine 1. 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 members 6a, 6b, 7 which define the exhaust passage 3 and 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 sensor 8 and 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 sensor 8 can be controlled stably at the desired temperature.