GAS SENSOR CONTROL DEVICE

摘要

A NOx sensor includes a pump cell, a monitor cell, and a sensor cell, and the pump cell discharges an oxygen in an exhaust gas introduced into a chamber. The sensor cell outputs a detected signal depending on a concentration of a NOx according to a gas after the oxygen is discharged. A microcomputer of a sensor control circuit temporarily changes an amount of the oxygen discharged by the pump cell, and then calculates output change amounts ΔIp, ΔIs, and ΔIm of the cells. The microcomputer performs a correction of the concentration of the NOx detected by the sensor cell and a deterioration diagnosis of the sensor cell, based on the output change amounts ΔIp, ΔIs, and ΔIm of the cells. When the sensor cell current Is is smaller than the monitor cell current Im, the microcomputer determines that the NOx sensor has an abnormality.

主权项

1. A gas sensor control device for a gas sensor including a first cell and a second cell each having a solid electrolytic element and a pair of electrodes disposed on the solid electrolytic element, the gas sensor discharging an oxygen in a detected gas introduced into a gas chamber, by using the first cell, and the gas sensor detecting a concentration of a specific component from a gas after the oxygen is discharged, by using the second cell, the gas sensor control device comprising:
an oxygen discharge amount changing section temporarily changing an oxygen discharge amount that is an amount of the oxygen that is discharged, by the first cell; a first calculating section calculating an actual discharge amount that is an actual amount of a change of the oxygen discharged when the oxygen discharge amount is changed by the oxygen discharge amount changing section; a second calculating section calculating an amount of output change which occurs in the second cell as a result of changing the oxygen discharge amount by the oxygen discharge amount changing section; and a main control section performing at least either correction of the concentration of the specific component as detected by the second cell or deterioration diagnosis of the second cell, based on the actual discharge amount as calculated by the first calculating section and the amount of output change of the second cell as calculated by the second calculating section.