We are designing a conductometric soot sensor that measures the change in conductance resulting from soot deposition onto the sensor. Although previous work has been done on conductometric soot sensing, current sensors are power intensive (5-30 W) and slow (60-170 s between sensing cycles) due to their large size, ineffective thermal insulation, and the high currents required for soot combustion (when self-regenerating). We propose to use MEMS fabrication methods to develop a miniaturized conductometric soot sensor with a built-in polysilicon microheater for self-regeneration, whose small size and good thermal isolation make it a fast and energy-effective sensor. Preliminary results show that the sensor has 100-1000 times lower power consumption and 2-5 times faster self-regeneration than current sensors, consuming 20-40 mW per sensing cycle and self-regenerating in less than 30 s. Sensor performance in an internal combustion engine and catalyst integration to lower the regeneration temperature are currently being tested.
Project end date: 08/26/15