Exhaust gas sensor

Abstract

An exhaust gas sensor, especially a lambda probe, preferably for motor vehicles, containing at least one reference electrode in a solid electrolyte and an exhaust gas electrode exposed to the exhaust gas, which has a porous ceramic coating is characterized by a circuit arrangement, through which an oxygen current flowing toward the exhaust gas electrode can be generated between a reference electrode and an exhaust gas electrode. The size of the oxygen current is adapted to the gas currents diffusing through the porous coating in such a way, that a targeted step change-displacement results.

Description

SHORT DESCRIPTION OF THE DRAWINGS

Additional advantages and characteristics of the invention are the subject matter of the following description as well as the technical depiction of the examples of embodiment.

The figures show the following:

FIG. 1 schematically the construction of an exhaust gas sensor;

FIG. 2 a circuit arrangement made use of by the invention to operate the exhaust gas sensor depicted in FIG. 1;

FIG. 3 the sensor voltage by way of the air number λ at a first sensor;

FIG. 4 the sensor voltage by way of the air number λ at a second sensor and

FIG. 5 the displacement of the lambda step change as a function of the porosity of the porous coating of the sensors according to the invention.

Claims

1. An arrangement including an exhaust gas sensor, especially a lambda probe, preferably for motor vehicles, containing at least one reference electrode disposed in a solid electrolyte and an exhaust gas electrode exposed to an exhaust gas, which has a porous ceramic coating, and including a circuit arrangement, through which an oxygen current flowing toward the exhaust gas electrode can be generated between a reference electrode and an exhaust gas electrode, wherein a size of the oxygen current is adapted to currents diffusing through the porous coating in such a way, that a targeted lambda-step change-displacement results.

2. An arrangement according to claim 1, further comprising a series circuit from a direct current voltage source, a resistor and the exhaust gas sensor, whereby a plus terminal of the voltage source is connected directly or by way of a series circuit with the resistor with the exhaust gas electrode, and a minus terminal is connected by a series circuit with the resistor, respectively directly with the reference electrodes.

3. An arrangement according to claim 1, wherein the porous coating has multiple plies.

4. An arrangement according to claim 3, wherein the plies of the porous coating in each case have different porosities.

5. An arrangement according to claim 1, wherein the exhaust gas sensor includes the circuit arrangement.