Suitability Assessment of NOx Emissions Measurements with PTI Equipment

The measurement of NOx emissions in vehicles has so far been exclusively carried out during the type-approval process. For this purpose, high-precision gas laboratory equipment and Portable Emission Measurement Systems (PEMS) are used. Both types costly terms price, maintenance, complexity, time use (calibration maintenance requirements). Currently, measurements Periodic Technical Inspections (PTIs) being considered, but PEMS or is unsuitable for function, PTI-grade to be Although CO O2 currently reliably measured with equipment, there not enough information about its accuracy measurements. Accordingly, paper, simultaneous measures have performed over same engine a test cell, PTI analyser assess latter. When performing most similar conditions found PTI, our results show that shows an average deviation 2.6 ppm 9% rel. respect concentrations below 700 NOx, which can considered acceptable periodic technical inspections.