2 October 2002

A final report from the first phase of the UK contribution to the European Particle Measurement Programme (PMP) has been published by Ricardo Consulting Engineers Ltd. The report describes an investigation into methodologies for the measurement of particles and particulates from heavy duty engines.

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The best repeatability levels were found for the particle mass and number measurement instruments Quartz Crystal Microbalance (QCM) and Condensation Nucleus Counter (CNC), respectively. Two candidate systems were recommended for further study in the Phase II PMP Programme:

  • CVS + secondary dilution + thermodenuder + CNC (measures particle number)
  • CVS + secondary dilution + QCM (measures particle mass)

Any of these methods could be added to the current CVS (Constant Volume Sampling) system used for the determination of PM mass emission. A comparison of transient cycles with steady state operating conditions revealed enhanced repeatability from the transients. Therefore, Ricardo concludes that there would be no gain in data quality by reverting to steady state type approval testing with any new procedure.

Background. The GRPE PMP program, formed in January 2001 and conducted under the auspices of the UNECE WP29/GRPE group, will produce a recommendation for new or additional PM measurement system to be used for EU type approval, testing and development of future emission standards for both light- and heavy-duty vehicles. The new PM measurement methods would include some particle size characterization parameters to address the nanoparticle emission issue. The objectives of the program are (1) to identify the best metrics for future particle measurements, (2) to determine instruments and methods utilizing those metrics, (3) to investigate a test procedure for the measurement of particles during type approval tests and finally, (4) to recommend a suitable test system or systems. The group’s recommendation is expected to be ready in 2003.

Source: Ricardo