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Technical Paper

Accuracy of Particle Number Measurements from Partial Flow Dilution Systems

The measurement of the particle number (PN) concentration of non-volatile particles ≻23 nm was introduced in the light-duty vehicles regulation; the heavy-duty regulation followed. Based on the findings of the Particle Measurement Program (PMP), heavy-duty inter-laboratory exercise, the PN concentration measurement can be conducted either from the full dilution tunnel with constant volume sampling (CVS) or from the partial flow dilution system (PFDS). However, there are no other studies that investigate whether the PN results from the two systems are equivalent. In addition, even the PMP study never investigated the uncertainty that is introduced at the final result from the extraction of a flow by a PN system from the PFDS. In this work we investigate the uncertainty for the three possible cases, i.e., considering a constant extracted flow from the PFDS, sending a signal with 1 Hz frequency to the PFDS, or feeding back the extracted flow to the PFDS.
Technical Paper

On-Road Emissions of Euro 6d-TEMP Vehicles: Consequences of the Entry into Force of the RDE Regulation in Europe

Human health and the environment are heavily impacted by air pollution. Air quality standards for Nitrogen dioxide (NO2) and particulate matter (PM) are commonly exceeded in Europe, particularly in urban areas with high density of traffic. Road transport contributed to 39% of NOx emissions, and 11% of PM emissions in the European Union (EU) in 2017. Measurements with Portable Emissions Measurement Systems (PEMS) showed that most Euro 5 and Euro 6b diesel vehicles emitted significantly more NOx on the road than their permissible limit in the laboratory type-approval test. In that context, EU Real Driving Emissions (EU-RDE) regulation aims at securing low on-road emissions of light duty vehicles under normal conditions of use. This paper assesses the tailpipe emissions performance of Euro 6d-TEMP gasoline and diesel passenger cars, type-approved after the entry into force of the RDE regulation in September 2017.
Journal Article

Development of Measurement Methodology for Sub 23 nm Particle Number (PN) Measurements

A proposal for sub-23 nm Solid Particle Number (SPN) measurement method was developed by the Particle Measurement Programme (PMP) group, based on the current SPN measurement method. In the proposal, a Particle Number Counter (PNC) having (65 ± 15)% counting efficiency at 10 nm and >90% at 15 nm (PNC10) replaces the current regulation PNC efficiency of 50±12% at 23 nm and >90% at 41 nm. Additionally, a catalytically active evaporation tube (CS) is required for sub-23 nm measurement method instead of the non-reactive evaporation tube (ET) of the current regulation. Here experimental work carried out at the JRC to address the issues of sub-23 nm SPN-measurement method is presented. The PNC10 was shown to be less dependent on the particle material than the PNC23, thus soot-like particles are still allowed for PNC-calibration. The high charging probability of soot-like particles was shown to have a low effect on PNC calibration uncertainties.