Characterisation of the Second Generation PMP “Golden Instrument”

The UN-ECE Particle Measurement Programme (PMP) has considerably gained momentum since the European Commission published the regulation details of Euro 5/6 for light duty vehicles, including a limit value for the number of particles emitted from passenger car tailpipes, to be enforced as early as Euro 5. A PMP-compliant particle number counting system retrieves its exhaust gas sample from a CVS tunnel and consists of two dilution stages before and after an evaporation tube, and a condensation particle counter. For each of these systems, compliance with the PMP guidelines has to be proved in terms of measurement performance. A required key property is the system's ability to evaporate liquid and volatile exhaust gas components, while properly transmitting solid particles to the number counter. Particle Number Count is able to distinguish between different filling states of a DPF as well as between DPF substrates with different porosity. Slight variations on the instrument set-up facilitate in-use-testing of DPF without uninstalling them. Future extension of particle number count to inspection and maintenance or mobile measurement will require compact, cost-effective equipment; corresponding instrumentation is currently being developed.