Industry report on exhaust particle measurements: a work within the EMIR1 project

The development of an analytical tool to measure particulate pollutants from combustion engines has been one of the major tasks within the EMIR1-project. The intention was to use the instrument in emission research studies and for the development of engine and exhaust after treatment systems. It was desired that the instrument should deliver a measure complementary to the regular mass based measurement of particulate matter, operating on a real-time scale. Furthermore, the instrument should be physically robust, show a high degree of analytical sensitivity and good repeatability. It should also be cost effective and easy to operate. The instrument thus developed measures particle number concentration by sampling from the CVS-tunnel by hot dilution. It consists of a heated ejector diluter followed by one or more ejector diluters in series operated at room temperature. This set-up ensures that only non-volatile particles are measured, preventing the measurements to be affected by highly variable phenomenons, such as nucleation, that are essentially impossible to control. The particle number concentration is measured by use of a Condensation Particle Counter. This report concerns measurements using the instrument developed within the EMIR1-project. The instrument has been used at Scania, GM Powertrain Sweden, and Volvo Car Corporation. The main goal with these measurements has been to evaluate the performance of the instrument, and the usability when performing measurements on various cars and engines with sampling from both the CVS-dilution tunnel and tailpipe. It has been found that the dilution ratio of both the heated ejector and the one following is affected by the operational temperature of the first. In order to determine the dilution ratio of the ejector diluters, it is concluded that the calibration of these, using trace gas measurements, should be performed in a careful manner. A high proportion of the particles measured in the size range 10-23 nm are associated with non-volatile material and are accordingly not removed by heated dilution in the EMIR1-instrument. All the participating laboratories have performed evaluations concerning the repeatability of measurements either using manually operated vehicles or fully automated operation of vehicles and engines. Generally, it has been found that the instrument is able to detect small excursions in the operation of the examined engine or vehicle. In the automated tests the repeatability in the measurements is improved and it is thus concluded that the instrument is a sensitive analytical tool showing good repeatability during repeated testing. Furthermore, it has been shown that the instrument is a suitable tool to detect minor defects in DPFs affecting the particle filtration performance. (A).


  • English

Media Info

  • Pagination: 21p+app
  • Serial:
    • Issue Number: 2007:07
    • ISSN: 1650-3104

Subject/Index Terms

Filing Info

  • Accession Number: 01089849
  • Record Type: Publication
  • Source Agency: Swedish National Road and Transport Research Institute (VTI)
  • ISBN: 978-91-85084-88-3
  • Files: ITRD
  • Created Date: Mar 17 2008 10:04AM