GAS SENSOR CONTROL DEVICE

摘要

An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes, while the solid electrolyte layer is interposed between the electrodes. The O2 sensor outputs an electromotive force signal in response to an air-to-fuel ratio of exhaust gas of an engine, which serves as a sensing subject. A constant current circuit, which induces a flow of a predetermined constant electric current between the pair of electrodes of a sensor element, and a current sensing arrangement, which senses a current value of an actual electric current that is conducted through the sensor element, are provided. A microcomputer determines whether an abnormality of the constant current circuit is present based on the current value of the electric current, which is sensed with the current sensing arrangement, in a case where the constant current is induced by the constant current circuit.

主权项

1. A gas sensor control device applied to an exhaust gas purifying device of an internal combustion engine, which includes:
a catalyst that is installed in an exhaust device of the internal combustion engine and purifies NOx, which is a lean component of an exhaust gas of the internal combustion engine, and a rich component of the exhaust gas; and a gas sensor that is installed at a location, which is in an intermediate portion of the catalyst or on a downstream side of the catalyst, to sense a gas component of the exhaust gas, which serves as a sensing subject, after purification of the exhaust gas with the catalyst, wherein the gas sensor includes an electromotive force cell, which has a solid electrolyte body and a pair of electrodes, to output an electromotive force signal in response to an air-to-fuel ratio of the exhaust gas, the gas sensor control device comprising: a current conduction regulating device that induces a flow of a predetermined constant electric current between the pair of electrodes of the electromotive force cell; a current sensing arrangement that senses a current value of an actual electric current, which is conducted through the electromotive force cell; and an abnormality determining unit that determines whether an abnormality is present in the current conduction regulating device based on the current value of the actual electric current, which is sensed with the current sensing arrangement, in a case where the flow of the predetermined constant electric current is induced by the current conduction regulating device.