Dilution system to remove volatile particles and to dilute highly concentrated aerosols for PMPD applications
The PMPD dilution system is used for emission measurements of vehicles and jet engines.
The PMPD system is a dilution system according to the ejector principle that was especially developed for the PMP application or the PMP measurement chain.
The Particle Measurement Programme or PMP is a programme for advancing the particle measurement technique for particulate vehicle exhaust gases.
The PMPD consists of a vaporisation line heated to 200°C, a dilution line also heated to 200°C, the thermodiluter to remove volatile particles, followed by a second unheated dilution step. Each dilution step has a dilution factor of 1:10, which corresponds to a total dilution factor of 1:100.
The efficiency of removing volatile particles was determined at METAS with 30 nm sized tetracontane (C40H82) droplets in accordance with "VPR Calibration Procedure AEA / ED47382 / Issue 5" (Volatile Particle Removal Efficiency) and is 0.99967.