GAS-SENSOR-CONTROL DEVICE AND CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

A constant current is made to flow between sensor electrodes by a constant current circuit provided in the outside of the oxygen sensor, whereby the output characteristics of an oxygen sensor can be changed. Further, when a specified current-switching-permission condition is met, a value of current flowing between the sensor electrodes is switched and a direct current resistance value (internal resistance value) of the oxygen sensor is computed from a difference in the output of the oxygen sensor and a difference in the value of the current between before and after switching the value of the current flowing between the sensor electrodes. Then, at the time of a constant current supply in which the constant current is made to flow between the sensor electrodes, in other words, when the output characteristics of the oxygen sensor are changed, an amount of output-voltage-variation is found from a constant current value and a direct resistance value at that time. Then, the output of the oxygen sensor is corrected by the use of the amount of output-voltage-variation. In this way, an air-fuel ratio control based on the output of the oxygen sensor can be performed with high accuracy.

主权项

1. A gas-sensor-control device having a gas sensor including a sensor element for sensing a concentration of a specified component contained in a gas, the sensor element having a solid electrolyte material arranged between a pair of sensor electrodes, the gas-sensor-control device comprising:
a constant current supply portion making a constant current flow between the sensor electrodes so as to change an output characteristic of the gas sensor; and an output-voltage-variation information computing portion computing an amount of output-voltage-variation of the gas sensor or an information correlating to the amount of output-voltage-variation (which is hereinafter generally referred to as “output-voltage-variation information”) at a time of a constant current supply in which the constant current flows between the sensor electrodes based on outputs of the gas sensor before and after switching a value of a current flowing between the sensor electrodes.