2010 Diesel Emission Reduction Consortium Experimental Studies of Exhaust Chemistry and Aftertreatment Professor Thatcher Root Department of Chemical and Biochemical Engineering September 21, 2004

2010 Diesel Emission Reduction Consortium DPF, LNT, DPNF Agenda l Investigate the link between surface chemistry and macroscopic trap behavior. – Chemical reactions to reaction engineering – Reaction parameters and model validation l Effects of engine operation via soot chemistry – Elemental vs. organic carbon with engine load – Trapping efficiency, reactivity during regeneration Trap diagnostics –  T,  P, sensors for O 2, NO x, … l Track soot and NO x accumulation – Link to surface chemistry – Eventual goal: control of cyclical operation

2010 Diesel Emission Reduction Consortium Diesel Particulate Matter Semi-Volatile Condensed Aerosol (VOC+sulfate+ H 2 O+ trace metal compounds) Elemental Carbon Agglomerate Adsorbed Semi- Volatile Compounds (VOC+sulfate+ H 2 O + trace metal compounds) 0.1  m

2010 Diesel Emission Reduction Consortium EC, OM, Sulfates (SO 4 ) in PM rpm1800 rpm Specific EC, OM, and sulfates shift significantly with the change in the engine load.

2010 Diesel Emission Reduction Consortium Chemical Characterization of Diesel Exhaust Augmented sampling system Sulfate ions Trace metals EC/OC PM Con. Organics Semi-volatile organics Size dist. - number - mass - volume Real-time PM - concentration - total mass - mass rate

2010 Diesel Emission Reduction Consortium Engine Layout Pressure Transducer Feed Gas Air Compressor From Fuel Tank pump

2010 Diesel Emission Reduction Consortium Fuel Burning System for Filter Regeneration Complete burner system for retrofit applications. OEM applications might use an air pump instead of compressed air. Power draw of the burner to heat exhaust to 650 C depends on the load point. 2% instantaneous fuel penalty is typical Zeuna Staerker, AVL International Commercial Powertrain Conference, Budapest, 10/01 Alternative: regeneration in external furnace for comparison with complete regeneration

2010 Diesel Emission Reduction Consortium DPF, LNT, DPNF Agenda l Investigate the link between surface chemistry and macroscopic trap behavior. – Chemical reactions to reaction engineering – Reaction parameters and model validation l Effects of engine operation via soot chemistry – Elemental vs. organic carbon with engine load – Trapping efficiency, reactivity during regeneration Trap diagnostics –  T,  P, sensors for O 2, NO x, … l Track soot and NO x accumulation – Link to surface chemistry – Eventual goal: control of cyclical operation

2010 Diesel Emission Reduction Consortium Chemistry in a Four-Way Catalyst The principle of combination diesel particulate/NO x reduction system. PM is oxidized in both lean and rich conditions. Periodic rich pulse causes PM to oxidize Toyota SAE

2010 Diesel Emission Reduction Consortium Trapped soot on inlet wall surface Cell Plugs Exhaust (Soot, CO, HC) Enter Exhaust (CO 2, H 2 O) Out Ceramic Honeycomb Wall with Supported Catalyst Plugged-monolith Wall-flow Filter Place a catalyst in front of or within filter to oxidize NO to NO 2

2010 Diesel Emission Reduction Consortium Mechanism for NO x Storage, Part I Adsorption, desorption, and reaction over Pt sites Rate parameters from Olsson et al. RhRhRhRh Al 2 O 3 NO + O 2 + ½O 2 Ba(NO 3 ) 2 BaCO 3 NO 2 CO 2 Pt Rh

2010 Diesel Emission Reduction Consortium Mechanism for NO x Storage, Part II NO x storage on Barium sites Rate parameters from Olsson et al. RhRhRhRh Al 2 O 3 NO + O 2 + ½O 2 Ba(NO 3 ) 2 BaCO 3 NO 2 CO 2 Pt Rh

2010 Diesel Emission Reduction Consortium Regeneration With Hydrocarbon Reduction of NO x with propene Rate parameters from Olsson et al. Al 2 O 3 CO + HC + H 2 PtPtPtPt BaCO 3 RhRhRhRh Ba(NO 3 ) 2 N2N2N2N2 + O 2 + CO 2 NOx CO O2O2