Sampling system for ground level aircraft engine particle matter (PM) emission measurement

A sampling method for testing particle emissions from aircraft engine(s), comprising:

• mounting one inlet probe at said aircraft engine exit plane with said probe inlet facing the exhaust plume substantially perpendicularly at the center of said plume cross section;
• associating one expansion chamber with said probe, wherein said probe is directing a flow of exhaust sample through said expansion chamber ensuring low particle matter resident time within said expansion chamber and allowing substantially no ambient air to enter said expansion chamber;
• expanding said exhaust sample within said expansion chamber having an expansion chamber inlet, discharging any excess exhaust through an open end to the ambient atmosphere and equalizing the pressure within said expansion chamber to about ambient pressure level;
• connecting said expansion chamber with at least one ejector having an ejector inlet, wherein each said ejector functions as a dilutor and in-line pump pulling said exhaust sample at a constant pressure level from the center line of said expansion chamber at an effective distance downstream from said expansion chamber inlet and upstream from said open end of said expansion chamber and pushing diluted said samples downstream;
• and
• testing said diluted sample with at least one particle matter measurement instrument.