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2 HC-SCR Catalyst for NO x Reduction in an Off-Road Diesel Engine Seppo Niemi and Kaj Lundin, University of Vaasa, Finland Janne Perus, Mika Laurén, Jani Hoikkala, Krister Ekman and Pekka Nousiainen, Turku University of Applied Sciences, Finland TUAS Kalle Arve, Kari Eränen and Dmitry Yu. Murzin, Åbo Akademi University, Finland

3 Outline Background Objectives Experimental setup Engine Fuels Matrix Analyzers Catalyst Performance HC production Emissions Fuel consumption Comparison with cooled EGR Conclusions and future targets

4 Background Strategies for emissions reduction, 2011 Cooled EGR, wall-flow diesel particulate filter (DPF) plus advanced turbo-charging A catalyst based on selective catalytic reduction of NO x (SCR) and an open-flow partial filter (pdpf) A high injection pressure for both options

5 Objectives To determine and optimize the performance of a prototype HC-SCR converter To compare the HC-SCR system with the conventional cooled EGR concept

6 Engine Manufacturer Engine Agco Sisu Power 33 CTA 2V Cylinder number 3 Bore Stroke Swept volume Injection system Turbocharger Intercooler Rated power Maximum torque 108 mm 120 mm 3.3 dm 3 Common rail Schwitzer S100 Air-to-water 75 kw at 2200 rpm 400 Nm at 1600 rpm

7 Fuels Low-sulfur diesel fuel oil S content from 6 to 10 mg/kg Total aromatics from 30 to 33% by mass Ash < 0.001%

8 Test matrix Speed Load 1200 rpm 50 and 100% 1600 rpm 50, 75 and 100% 2200 rpm 50%

9 Emissions analyzers Substance Manufacturer Model Technology O 2 CO Servomex Xentra 4900 CO 2 Paramagnetic sensor Non-dispersive infrared (NDIR) HC CAI 300-HFID Flame ionization detector (HFID) NO, NO 2 Eco Physics CLD 700EL ht Chemiluminescent detector (CLD) Smoke AVL 415 S G002 Optical Filter PM (number) Dekati Ltd ELPI Electrical low-pressure impactor

10 An Ag/alumina catalyst Cordierite monoliths 400 cpsi Catalyst Bricks arranged in the converter with free spaces between each monolith An oxidation catalyst for CO and HC downstream the SCR catalysts

11 Production of HCs rpm 50%; 120 ATDC 100%; 150 ATDC HC1/NOx Post-injection quantity [mg]

12 NO reduction x Change in NOx [%] rpm 50% load 100% load HC 1 /NO x

13 Fuel penalty Increase in BSFC [%] rpm/50% 1200 rpm/100% 2200 rpm/50% NO x reduction [%]

14 HC reduction rpm / 50% Change in BSHC [%] Post-injection fuel quantity [mg]

15 NO x comparison: SCR/EGR rpm Relative BSNOx Load [%] EGR SCR, 0 mg/str SCR, 2 mg/str SCR, max post

16 HC comparison: SCR/EGR Relative BSHC rpm Load [%] EGR SCR, 0 mg/str SCR, 2 mg/str SCR, max post

17 Smoke: SCR/EGR rpm Relative smoke Load [%] EGR SCR, 0 mg/str SCR, 2 mg/str SCR, max post

18 Fuel consumption: SCR/EGR rpm Relative BSFC Load [%] EGR SCR, 0 mg/str SCR, 2 mg/str SCR, max post

19 Particles: SCR/EGR BSPM (1/kWh) 1.E+12 1.E+11 1.E+10 1.E+09 1.E rpm, 100% load EGR 0mg/str 2 mg/str 20 mg/str 1.E Aerodynamic diameter (nm)

20 Main conclusions 1 The NO x reduction increased with HC 1 /NO x ratio The highest reduction was 70% Usually, the performance was the better, the lower the load Fuel consumption increased with NO x reduction At the best NO x performance, a fuel penalty of 13% was recorded At a certain NO x reduction, the relative fuel loss increased with engine load

21 Main conclusions 2 Compared with short-route cooled EGR, The HC-SCR was usually superior with respect to smoke and HC NO x also decreased with the highest postinjection fuel dosage Larger than ultra-fine particles were reduced considerably and ultra-fine particles were lower relative to EGR Fuel consumption increased significantly

22 Main conclusions 3 The NO x reduction performance of the studied HC-SCR converter must be notably improved Urea-SCR routinely reaches efficiencies of approximately 90%, as seem to do the NO x storage catalysts The size of the converter has to be reduced The common-rail post-injection may have to be replaced by separate fuel injection into the exhaust pipe

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