| The Electrical Low Pressure Impactor (ELPI), the Scanning Mobility Particle Sizer (SMPS) and the Condensation Particle Counter (CPC) are used to examine nanoparticle number concentrations and particle size distributions from eight vehicles representing different engine technologies. Five drive cycles along with several steady state cycles were used with two exhaust dilution methods.;The test set-up for studies of particle size distribution should include an aerosol neutralizer, since particles exit the tailpipe with a charge. To minimize particle formation and losses, heat is needed for dilution (particularly the mini-diluter, the dilution ratio is higher in the tunnel so heat is not essential). In addition, dilution with diesel vehicles requires a second mini-diluter.;According to the particle size distributions collected for the various vehicles, the electric hybrid has the lowest emissions, followed by the multi-port fuel injected spark ignition engine, the direct injection gasoline engine and the direct injection diesel engine. |
