High-accuracy Nanoparticle Sensor for Combustion Engine Exhaust Gases

Nanoparticles are one indispensable analyte in the characterisation of any combustion engine or exhaust aftertreatment system. To improve the presently prevalently used condensation nucleus magnification-based particle counters (CNC) in performance and footprint, a dedicated, comprehensive all-in-one CFD model was developed. Following experimental validation, the model was successfully used to simulate and better comprehend the internal functionings of the present standard system, identify critical design parameters and develop a new, improved sensor system design. The ensuing improved CNC nanoparticle sensor is now based on a vertical, annular design. Besides being highly compact, the new layout yields an almost perfectly homogenous (super-)saturation of the aerosol stream and superior temperature control of all relevant components. This gives the new design a uniquely high discriminatory power by nanoparticle diameter, a precise controllability of the effective particle detection cut-on size and a significant reduction in the effective particle losses in the sensor.