| 摘要 |
The invention relates to a method for the self-diagnosis of a particle sensor used for determining a particle content in a gaseous stream, wherein the particle sensor includes on its surface at least two interlocking, interdigital electrodes and a heating element separated from said electrodes by an insulation layer. Said particle sensor can be heated by said heating element in a regeneration phase, and a soot concentration can thereby be removed from the same. Provision is made according to the invention for a semiconductive layer to be formed in the insulation layer directly beneath the electrodes by means of external doping or auto-doping and in order to perform the self-diagnosis for a measurement voltage to be applied at least periodically between the electrodes and a self-diagnostic current to be measured. The invention furthermore relates to a device for the self-diagnosis of a corresponding particle sensor, said particle sensor being connected to an engine management system or a sensor control unit and said engine management system or said sensor control unit including apparatuses for diagnosing the soot concentration on the particle sensor and the particle sensor itself. Said engine management system or said sensor control unit includes according to the invention apparatuses for evaluating a self-diagnostic current when applying an AC or DC voltage as a measurement voltage to the electrodes. When using DC voltage as the measurement voltage, the particle sensor can furthermore be heated for a short time to temperatures >500 EC via said engine management system or said sensor control unit in order to perform the self-diagnosis. A self-diagnosis of the electrodes, which are provided for the particle measurement, can be carried out as a pre-delivery inspection by the manufacturer as well as in subsequent use with the presented diagnostic method and the corresponding device for carrying out this method. A preferred application of the method provides for its use within the scope of the on-board diagnosis of diesel internal combustion engines.
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