GAS SENSOR CONTROL DEVICE AND INTERNAL COMBUSTION ENGINE CONTROL DEVICE

摘要

The output characteristics of an oxygen sensor (21) can be changed by allowing a constant current to flow between sensor electrodes by using a constant current circuit provided outside the oxygen sensor (21). When a predetermined current change allowing condition is satisfied, a gas sensor control device changes the values of current flowing between the sensor electrodes and calculates the DC resistance value (internal resistance value) of the oxygen sensor (21) from the difference between the outputs of the oxygen sensor (21) before and after the change and the difference between the current values. During a constant current supply period in which a constant current is allowed to flow between the sensor electrodes, that is, during the changing period of the output characteristics of the oxygen sensor (21), the gas sensor control device obtains an output voltage variation from the constant current value in this period and the DC resistance value and uses the output voltage variation to correct the output of the oxygen sensor (21). This makes it possible to accurately perform an air-fuel ratio control based on the output of the oxygen sensor (21).