Patent ID: 9714928
Date: 2017-07-25
CPC Classifications: F01N,F02B,G01N,Y02T

Claim:
1. A gas-sensor control device mounted to a vehicle comprising: a sweep circuit energizing a detection current to flow through a gas sensor including an atmosphere-side electrode, an exhaust-side electrode, and a solid electrolyte portion, the solid electrolyte portion being interposed between the atmosphere-side electrode and the exhaust-side electrode; a return sweep circuit energizing a neutralization current to flow through the gas sensor in a direction opposite to a direction of the detection current, to discharge accumulated electric charge from the gas sensor that is energized by the detection current; an offset-voltage generating circuit applying a voltage to the gas sensor such that a voltage of the atmosphere-side electrode is less than a voltage of the exhaust-side electrode, when the neutralization current flows through the gas sensor; an acquiring circuit acquiring a voltage value between the atmosphere-side electrode and the exhaust-side electrode; a control portion acquiring a temperature of the gas sensor based on an impedance of the gas sensor calculated by using the voltage value acquired by the acquiring circuit and a value of the detection current in a case where the detection current flows through the gas sensor, the control portion executing a temperature control of the gas sensor according to the temperature, wherein the control portion executes a detection of an off failure of the sweep circuit and the return sweep circuit, only based on the voltage value acquired by the acquiring circuit in a time period where the neutralization current flows through the gas sensor, and a threshold, and in the off failure, the sweep circuit or the return sweep circuit is maintained to be turned off while the sweep circuit or the return sweep circuit is controlled to be turned on.