Electrostatic sensing of particulates provides the most robust and cost-effective in-situ measurement of particulate matter available in the market today. With proven resolution to less than 0.5 mg per cubic meter, ePM/PMTrac® is ideal for any application in which quantification of near-zero PM or PN is required.  

BASICS of operation

The basic sensor is a high voltage (~1kV) concentric electrostatic trap. Field directed assembly of soot dendrites result in an equilibrium in which highly charged soot agglomerates exit the sensor, and the charge loss is proportional to particulate matter mass concentration (PM) or Particulate Number (PN). Aerosol Scientists from Ford Motor Company have published a good paper on the measurement principle, and more recently further study of application for monitoring particulate filters.

proven performance

Both independent labs and OEMs have done extensive testing of the ePM technology, establishing very high levels of correlation to reference instruments. One recent technical paper of interest is SAE 2020-01-0385: Evaluation of an On-board, Real-time Electronic Particulate Matter Sensor Using Heavy-duty On-highway Diesel Engine Platform.  Much of the testing work done by private companies or closed consortiums is not available for public disclosure. However, evaluation kits are available for purchase directly from Emisense.

Next generation applications

While current generation resistive accumulator sensors are used for existing OBD applications, it is doubtful that they will perform well in next-generation applications. For GDI, China-6b, Euro-7, and higher CARB performance ratios, in-situ sensors need to combine a low detection threshold with good accuracy and response time. Only PMTrac® ePM technology can achieve this combination.

Serial production & patent licensing

In conjunction with our manufacturing partners, Emisense is capable of serving as a Tier-1 or Tier-2 supplier of complete sensor systems. Current capacity is 30K sensors/month at our ISO-certified facility. The ePM patent portfolio is also available for licensing. If your company has manufacturing expertise and sales channels in a specific field of use, please contact us to explore partnership opportunities.