Be used switchable folding pathway standards for temperature compensation, to determine the load on the filter from the radio-frequency transmission loss of the diesel particulate filter

摘要

The temperature used for the unknown ambient or DPF sensor calibration at different ambient temperatures, the method and apparatus are disclosed determining the attenuation of the RF signal due to DPF. The method and apparatus, by obtaining the attenuation of the folding pathway disconnect the antenna, determine the sensor attenuation just before obtaining the DPF attenuation. Then, folded path, cable, and the attenuation obtained for normal path including attenuation due to DPF, it is possible to subtract the sensor decay. In this way, variations in sensor decay due to changes in ambient temperature of the sensor is compensated. By determining the cause reveal the item of variations due to changes in ambient temperature, additional temperature compensation is achieved. .FIELD 1