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Four dynamic PM measurement instruments (EEPS3090, DMS500, DMM230, AVL483) are studied in terms of their usability for diesel exhaust measurements under transient and steady state conditions. Measurements for various engine and exhaust aftertreatment strategies as well as on a Combustion Aerosol Standard (CAST) were conducted. The utilized sampling concepts comprised pre-DPF, tailpipe and CVS tunnel measurements. All results obtained from the two particle size spectrometers (EEPS3090 and DMS500) were compared to corresponding SMPS and CPC values, while the PM mass measurement instruments (DMM230 and AVL483) were compared to filter data. In addition, PM mass was estimated from the transient particle size spectra of EEPS3090 and DMS500, assuming different particle density functions, and was also compared to the corresponding filter data. All instruments were suitable to resolve fast changes in PM emissions.

This paper presents an alternative and relatively simple method which allows the use of ordinary ejector-type diluters over a wide range of sample inlet conditions including elevated pressures and temperatures. After calibration of the ejector diluter, the dilution can be accurately characterized using only the pressures at the inlet and the outlet of the diluter and the sample temperature. The method is based on a semi-empirical, stationary model taking into account the critical parameters needed to predict the dilution factor. Under steady state operation it achieves accuracies estimated to be below ±8% (95% confidence interval) for diluter inlet pressures in the range of 1000 - 4000 mbar absolute and temperatures between 20 - 200°C. Performance under actual vehicle testing conditions is evaluated upstream of the DPF for a diesel vehicle run on a chassis dynamometer.