Comparing emission rates derived from remote sensing with PEMS and chassis dynamometer tests - CONOX Task 1 report
In this report a newly developed method is presented to enable improved comparisons of emission results from remote sensing measurements with those from PEMS routes or from chassis dynamometer standard driving cycles, which together will help to corroborate measurements and better understand real-driving emissions of in particular NOX from late model diesel light-duty vehicles, e.g. Euro 5 and Euro 6 passenger cars. The method utilizes information and data commonly available from remote sensing measurements, such as speed, acceleration and road grade, together with crucial vehicle information, such as vehicle segment, engine/fuel type and Euro classification. From this information the vehicle specific power (VSP) is calculated on an individual vehicle level, which is used as input to simulations with the TU Graz PHEM model to derive instantaneous fuel rates on an individual or aggregated vehicle level. The derived fuel rates are used to convert emissions expressed as gram pollutant emitted per kg fuel burned from the remote sensing measurements into gram pollutant emitted per vehicle distance driven (e.g. g/km). By dividing large remote sensing datasets into VSP bins, the proposed method can be used to convert remote sensing emission rates to any test cycle, such as the WLTP, for further comparisons.