Emission Control Science and Technology

, Volume 4, Issue 4, pp 247–259 | Cite as

Evaluation of Partial Flow Dilution Systems for Very Low PM Mass Measurements

  • Liem Pham
  • Jiacheng Yang
  • Kent JohnsonEmail author
  • Thomas Durbin
  • Georgios Karavalakis
  • Wayne Miller
  • David Kittelson
  • Heejung S. Jung


Particulate matter (PM) mass measurement methodologies were improved considerably with the application of Title 40 Code of Federal Regulations Part 1065 for the 2007 standards for heavy-duty engines that emphasized PM. However, there is still a need to improve the understanding of and the confidence in mass measurements for light-duty vehicles, which are now being subjected to more stringent PM standards. The purpose of this study is to evaluate commercially available partial flow dilutors (PFDs), with a particular focus on their equivalency with the standard constant volume sampler (CVS) tunnel method and the ability to provide reproducible measurements at low PM emission levels. For the main PFD comparison, simultaneous testing was conducted with the three PFDs, over federal test procedure (FTP) and US06 tests. The results of the calibrations and proportionality tests all showed good performance for the PFDs. The exhaust flow meters (EFMs) for the PFDs showed measurements within 2% or less of a calibration source. The PFDs also showed good level proportionality and can easily meet the CFR 1066 requirements for light-duty vehicles and 1065 requirements for all tests performed. Larger differences were seen for the main comparisons between the CVS and the different PFDs during the FTP testing, with the relative difference of PM emissions between the PFDs and the CVS varying from − 16.5 to − 0.6%, with an average pooled difference of − 8.5%. These FTP differences only represented 0.00 to 0.11 mg/mile on an absolute basis, however, and could be attributed to difficulties making and weighing filter mass measurements at such low levels. For the US06 cycle, the differences between the PFDs and the CVS were not statistically significant and ranged from − 6.7 to − 0.7% and up to 0.07 mg/mile.


Particle emission Vehicle emission Emission control Particle measurements 



Standard deviation


Phase of the FTP bag measurement system


College of Engineering-Center for Environmental Research and Technology (University of California, Riverside)


Code of Federal Regulations


Carbon monoxide


Carbon dioxide


Constant volume sampling


Dilution factor


Elemental carbon as defined by NIOSH methods


Exhaust flow meter


United States Environmental Protection Agency


Ten percent ethanol in gasoline blend by weight


Filter face velocity


Federal test procedure


Gasoline direct injection


Inner diameter


International Organization for Standardization


Light-duty vehicles


Low-emission vehicle


Mass flow controller


National Institutes of Safety and Health method


National Institute for Standards and Technology


Organic carbon


Outer diameter


Partial flow dilution system


Particulate matter




Standard error estimate


US06 test cycle



The authors acknowledge Mr. Mark Villela, Mr. Daniel Gomez, Mr. Kurt Bumiller, and Mr. Edward O’Neil of the University of California, Riverside, for their contributions in conducting the emissions testing for this program. The authors acknowledge Ms. Lauren Ackock and Ms. Grace Johnson for their contributions in filter weighing.

Funding Information

The authors acknowledge funding from the Coordinating Research Council under the E-99-2 project.

Compliance with Ethical Standards

The authors declare that they have no competing interests.

Supplementary material

40825_2018_99_MOESM1_ESM.docx (1.2 mb)
ESM 1 (DOCX 1238 kb)


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Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringUniversity of California, RiversideRiversideUSA
  2. 2.College of Engineering-Center for Environmental Research and Technology (CE-CERT)University of California, RiversideRiversideUSA
  3. 3.Department of Mechanical EngineeringUniversity of MinnesotaMinneapolisUSA

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