ePNC Diffusion-Charging Based Particle Number Counting Technology as Alternative to Condensation Particle Counting Based Methods

Particle Number (PN) measurement testing has for long been conducted by using Condensation Particle Counter (CPC) based technology. While accurate at low concentrations, CPC has nevertheless several drawbacks for in-field use, such as the use of a working fluid, the need for dilution, the delicate optical components and the sensitivity to contamination. Diffusion Charging (DC) based particle counting technologies have often been disregarded as a valid alternative to CPC based methods due to their intrinsic particle size dependent counting efficiency and lower sensitivity. However, Dekati’s novel ePNC PN technology has brought DC technology to the next level. Due to its patented technology, the Dekati ePNC’s particle counting efficiency is nearly size independent, turning DC as a competing technology for CPC, especially for demanding field applications, such as Periodic Technical Inspection (PTI), Portable Emission Measurement Systems (PEMS) for Real Driving Emissions (RDE), and brake and tire wear measurements. These applications require the ability to continuously measure elevated particle concentrations with sufficient accuracy in often harsh environments such as garages or during on-road testing. In this study we will look closer into the ePNC technology and show the results of recent measurement campaigns that prove the suitability of the Dekati ePNC’s DC technology as an alternative to CPC methods. For example, during vehicle type approval style chassis dynamometer measurement ePNC technology was found to produce comparable results against a PMP reference (7% difference in emission factor).