| 摘要 |
The invention relates to a device for operating a broadband lambda probe in the exhaust gas duct of an internal combustion engine and for detecting information about the operating state of the broadband lambda probe, wherein said broadband lambda probe has a cavity connected via a diffusion barrier to the exhaust gas duct, a Nernst cell connected to the cavity and a pump cell connected to the cavity, as well as an electrical heating device. In the operating device, the invention provides an electronic circuit for determining the internal resistance of the pump cell and for controlling the heating device on the basis of the internal resistance of the pump cell. The invention further relates to a corresponding method. The method and device enable improved regulation of the temperature of the broadband lambda probe and more precise maintenance of threshold values for the exhaust gas composition. A determination of the temperature by means of the internal resistance of the pump cell is especially advantageous, because the pump cell is arranged particularly closely to the diffusion barrier, and the temperature of the barrier, alongside that of the pump cell itself, must be known and specified for high precision when determining the composition of the gas mixture in the exhaust gas duct. The measuring current through the pump cell can be higher than the measuring current through the Nernst cell because the measuring current of the Nernst cell must be kept as low as possible in order to prevent polarization of the Nernst cell. Due to its higher absolute value, the measuring current through the pump cell is less susceptible to interference influences.
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