REAL-TIME SOOT MEASUREMENT IN A DIESEL PARTICULATE FILTER

摘要

Methods and apparatus for detecting the filtering state of a filter, such as a particulate filter. Some embodiments include one or more capacitive sensors that provide a signal corresponding to the filtered state of the filter with a change in measured capacitance. A novel ECT based sensing technique for soot load estimation in a diesel particulate filter is presented. The sensing technology is based on principle that deposited soot thickness inside DPF causes a variation in the dielectric constant which has a direct impact on the capacitance of ECT system and its output voltage. The sensor can be built into the DPF outer shell as indicated in the design. The simulation results demonstrate that there is a direct relationship between the amount of soot load in the DPF and the output voltage of the ECT system which can be used to estimate the soot load.

主权项

1. A method for sensing, comprising:
providing a filter having a flowpath therethrough and a media for trapping material in the flowpath, the media having a plurality of sides, a first electrically conductive plate on a side of the flowpath, a second electrically conductive plate on a side of the flowpath, a third electrically conductive plate a side of the flowpath, each of the first, second, and third plates being spaced apart from one another, and a voltage source having a signal lead and a common lead and capable of supplying a transient voltage to the signal lead relative to the common lead; placing the first plate in electrical communication with the signal lead; placing the second plate and the third plate in electrical communication with the common lead applying an input transient voltage with the source to the signal lead; measuring the capacitance of the second plate relative to the first plate; and measuring the capacitance of the third plate relative to the first plate.