Patent ID: 8828205
Filing Date: 2014-09-09
Classification: F02D,G01N

Abstract:
1. A gas sensor, especially a lambda sensor, for determination of an oxygen concentration in an exhaust gas of a combustion engine operated by a fuel-air-mixture, the gas sensor comprising: a. a first measurement chamber and a second measurement chamber; b. an inner electrode arranged in the first measurement chamber and separated from the exhaust gas by a first diffusion barrier; c. an outer electrode arranged in the second measurement chamber and separated from the exhaust gas by a second diffusion barrier; and d. an electronic circuit for the production of a voltage between the outer electrode and the inner electrode and for measurement and evaluation of a pump current in order to imply the composition of the fuel-air-mixture; wherein a diffusion coefficient of the second diffusion barrier differs from a diffusion coefficient of the first diffusion barrier and wherein the electronic circuit is configured for a repeated pole reversal of the voltage; wherein the electronic circuit is configured to measure a first pump current prior to a reversal of voltage polarity and a second pump current after the reversal of voltage polarity, wherein the electronic circuit is further configured to compare the first pump current and the second pump current to determine whether a rich gas or a lean gas is present, and wherein the electronic circuit is configured to produce a rectangular alternating pump voltage waveform as the repeated pole reversal of the voltage.