Theory and simulation of a miniature zirconia sensor for control of the air-to-fuel ratio in combustion systems

The theory of operation on both sides of stoichiometry of a miniature zirconia oxygen pump-gauge incorporating a diffusion hole is discussed. Computer simulation of the sensor output when used for monitoring the air-to-fuel ratio in a combustion system burning pure methane in air is given. It is shown that for a sinusoidal current applied to the pump, the gauge provides an oscillating EMF from which the air-to-fuel ratio may be determined unambiguously without the use of a reference and/or pseudo-reference.