Developing a 55+ BTE Commercial Heavy-Duty Opposed-Piston Engine Without a Waste Heat Recovery System

  • Neerav AbaniEmail author
  • Michael Chiang
  • Isaac Thomas
  • Nishit Nagar
  • Rodrigo Zermeno
  • Gerhard Regner
Conference paper
Part of the Proceedings book series (PROCEE)


Heavy-duty vehicles, currently the second largest source of fuel consumption and carbon emissions are projected to be fastest growing mode in transportation sector in future. There is a clear need to increase fuel efficiency and lower emissions for these engines. The Achates Power Opposed-Piston Engine has the potential to address this growing need. In this paper, results are presented for a 9.8L three-cylinder OP Engine that shows the potential of achieving 55% brake thermal efficiency (BTE), while simultaneously satisfying emission targets for tail pipe emissions. The Achates Power OP Engines are inherently 20% more cost effective. The OP Engine architecture can meet this performance without the use of waste heat recovery systems or turbo-compounding and hence is the most cost effective technology to deliver this level of fuel efficiency.

The Achates Power OP Engine employs currently available engine components, such as supercharger, turbocharger and after-treatment and features a uniquely designed piston bowl shape to enhance mixing with a swirl-to-tumble conversion as the piston bowls approach minimum volume. This design improves fuel-air mixing and hence, results in low soot values, higher indicated thermal efficiency (ITE) due to better combustion phasing because of faster mixing controlled combustion and lower NOx due to lower fueling requirement because of two-stroke and more efficient combustion system. The OP Engine has a lower heat transfer loss due to the inherent design of the combustion chamber, which provides lower surface area-to-volume ratio compared to a conventional engine. This results in further benefits of reduction in fuel consumption and green house gases (GHGs).

The Achates Power OP Engine also makes use of internal exhaust gas recirculation (EGR) by using an optimized design of intake and exhaust ports that improves scavenging. This reduces engine-out NOx along with lower requirement of flowing external EGR and hence reduction in pumping requirement. 1-D and 3-D-CFD models developed for the analysis were correlated to the Achates Power 4.9L OP Engine dynamometer measured data. The correlated models were used as tools to make predictions for the 9.8L heavy-duty engine. The optimized system include high trapped compression ratio piston bowl, ports design to provide best scavenging performance, thermal barrier coating on piston bowls and dual injector with having an optimized spray pattern layout. Results show that the OP Engine results in a BTE of 55%, while meeting stringent emission standards without the use of expensive waste heat recovery systems and/or turbo-compounding components. The Achates Power OP Engine offers a solution to the automotive industry in providing a commercially viable, highly efficient and clean heavy-duty diesel engine that will reduce GHGs and carbon footprint for heavy-duty vehicles such as Class 8 trucks.


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  1. 1. “EPA and NHTSA Propose Greenhouse Gas and Fuel Efficiency Standards for Medium- and Heavy-Duty Trucks: By the Numbers”,, EPA-420-F-15-903, June 2015.
  2. 2. Delgado, O, and Lutsey, N., “ The U.S. SuperTruck Program: Expediting the development of Advanced heady-Duty Vehicle Efficiency Technologies”, International Council of Clean Transportation, June 2014.Google Scholar
  3. 3. Koeberlein, D., “Technology and System Level Demonstration of Highly Efficient and Clean, Diesel Powered Class 8 Trucks,”, DoE report, project ID: ACE057, 2015.
  4. 4. Singh, S., “Recovery Act – Class 8 Truck Freight Efficiency Improvement Project”,, DoE report, project ID: ACE058, June 2015.
  5. 5. Zukouski, R., “SuperTruck – Development and Demonstration of a Fuel-Efficient Class 8 Tractor & Trailer Engine Systems”,, DoE report, project ID: ACE059, 2016.
  6. 6. Amar, P., Gibble, J., “ SuperTruck Powertrain Technologies for Efficiency Improvement”,, DoE report, project ID: ACE060, 2016.
  7. 7. Hanson, R., Reitz, R.D., Splitter, D., and Kokjohn, S., “An Experimental Investigation of Fuel Reactivity Controlled PCCI Combustion in a Heavy-Duty Engine,” SAE paper 2010-01-0864, SAE Int. J. Engines, Vol. 3, No.1, pp. 700-716, 2010.Google Scholar
  8. 8. Kokjohn, S.L., Hanson, R.M., Splitter, D.A., and Reitz, R.D., “Fuel Reactivity Controlled Compression Ignition (RCCI): A Pathway to Controlled High-Efficiency Clean Combustion,” International Journal of Engine Research, Special Issue on Fuel Efficiency, Vol. 12, pp. 209-226, 2011.Google Scholar
  9. 9. Hanson, R., Ickes, A., and Wallner, T., “Comparison of RCCI Operation with and without EGR over the Full Operating Map of a Heavy-Duty Diesel Engine,” SAE Technical Paper 2016-01-0794, 2016, doi: 10.4271/2016-01-0794.
  10. 10. Manente, V., Zander, C., Johansson, B., Tunestal, P. et al., “An Advanced Internal Combustion Engine Concept for Low Emissions and High Efficiency from Idle to Max Load Using Gasoline Partially Premixed Combustion,” SAE Technical Paper 2010-01-2198, 2010.Google Scholar
  11. 11. Chang, J., Kalghatgi, G., Amer, A., Adomeit, P. et al., “Vehicle Demonstration of Naphtha Fuel Achieving Both High Efficiency and Drivability with EURO6 Engine-Out NOx Emission,” SAE Int. J. Engines6(1):101-119, 2013.Google Scholar
  12. 12. Sharma, A. and Redon, F., “Multi-Cylinder Opposed-Piston Engine Results on Transient Test Cycle,” SAE Technical Paper 2016-01-1019, 2016Google Scholar
  13. 13. Regner, G., Herold, R., Wahl, M., Dion, E. et al., “The Achates Power Opposed-Piston Two-Stroke Engine: Performance and Emissions Results in a Medium-Duty Application,” SAE Int. J. Engines 4(3):2726-2735, 201Google Scholar
  14. 14. Naik, S., Redon, F., Regner, G., and Koszewnik, J., “Opposed-Piston 2-Stroke Multi-Cylinder Engine Dynamometer Demonstration,” SAE Technical Paper 2015-26-0038, 2015Google Scholar
  15. 15. Redon, F., Kalebjian, C., Kessler, J., Rakovec, N. et al., “Meeting Stringent 2025 Emissions and Fuel Efficiency Regulations with an Opposed-Piston, Light-Duty Diesel Engine,” SAE Technical Paper 2014-01-1187, 2014Google Scholar
  16. 16. Venugopal, R., Abani, N., and MacKenzie, R., “Effects of Injection Pattern Design on Piston Thermal Management in an Opposed-Piston Two-Stroke Engine,” SAE Technical Paper 2013-01-2423, 2013.Google Scholar
  17. 17. Herold, R., Wahl, M., Regner, G., Lemke, J. et al., “Thermodynamic Benefits of Opposed-Piston Two-Stroke Engines,” SAE Technical Paper 2011-01-2216, 2011Google Scholar
  18. 18. Dion, E. P., Lenski, B. M.., and Mackenzie, R. G., “Piston constructions for opposed-piston engines” US 20120073526, 2012.Google Scholar
  19. 19. Senecal, P.K., Richards, K.J., Pomraning, E., Yang, T., Dai, M.Z., McDavid, R.M., Patterson, M.A., Hou, S., and Shethaji, T., “A New Parallel Cut-Cell Cartesian CFD Code for Rapid Grid Generation Applied to In-Cylinder Diesel Engine Simulations,” SAE Paper No. 2007-01-0159, 2007.Google Scholar
  20. 20. Patel, A., Kong, S. C., and Reitz, R.D., “Development and Validation of a Reduced Reaction Mechanism for HCCI Engine Simulations,” SAE Technical Paper 2004-01-0558, 2004.Google Scholar
  21. 21. Kong S.C., Sun Y., and Reitz R.D., Modeling diesel spray flame lift-off, sooting tendency and NOx emissions using detailed chemistry with phenomenological soot models, ASME J. Eng. Gas Turbines Power 129 (2007), pp. 245–251.Google Scholar
  22. 22. Smith G.P., Golden D.M., Frenklach M., Moriarty N.W., Eiteneer B., Goldenberg M., Bowman C.T., Hanson R.K., Song S., Gardiner W.C., Lissianski V.V., and Qin Z., 2000 []
  23. 23. Hiroyasu, H., and Kadota, T., “Models for Combustion and Formation of Nitric Oxide and Soot in DI Diesel Engines,” SAE Paper No. 760129, 1976.Google Scholar
  24. 24. Nagle, J., and Strickland-Constable, R.F., “Oxidation of Carbon Between 1000-2000 C,” Proceedings of the Fifth Carbon Conference, Vol. 1, p.154, 1962.Google Scholar
  25. 25. Patterson, M.A., “Modeling the Effects of Fuel Injection Characteristics on Diesel Combustion and Emissions,” Ph.D. Thesis, University of Wisconsin-Madison, 1997.Google Scholar
  26. 26. Abani, N., and Reitz, R.D., “Diesel engine emissions and combustion predictions using advanced mixing models applicable to fuel sprays”, Combustion Theory and Modelling, Vol. 14, Iss. 5, pp 715-746, 2010.Google Scholar
  27. 27. O’Rourke, P.J., “Collective Drop Effects on Vaporizing Liquid Sprays,” Ph.D. Thesis, Princeton University, 1981.Google Scholar
  28. 28. Han, Z., and Reitz, R.D., “Turbulence Modeling of Internal Combustion Engines Using RNG k-ε Models,” Combustion Science and Technology, Vol. 106, 1995.Google Scholar
  29. 29. Klyza, C., “Optical Measurement Methods used in Calibration and Validation of Modeled Injection Spray Characteristics,” Poster P7, presented in the 2010 Directions in Engine-Efficiency and Emissions Research (DEER) Conference.Google Scholar
  30. 30. Abani, N., Kokjohn, S., Park, S., Bergin, M. et al., “An Improved Spray Model for Reducing Numerical Parameter Dependencies in Diesel Engine CFD Simulations,” SAE Technical Paper 2008-01-0970, 2008, doi: 10.4271/2008-01-0970..
  31. 31. Taraza, D., Henein, N. A., Ceausu, R., and Bryzik, W., “Engine Friction Model for Transient Operation of Turbocharged, Common Rail Diesel Engines”, SAE Technical paper 2007-01-1460, 2007.Google Scholar
  32. 32. Stanley, R., Taraza, D., Henein, N., and Bryzik, W., “A Simplified Friction Model of the Piston Ring Assembly”, SAE Technical paper 1999-01-0974, 1999.Google Scholar
  33. 33. Taraza, D., Henein, N., and Bryzik, W., “Friction Losses in Multi-Cylinder Diesel Engines”, SAE Technical Paper 2000-01-0921, 2000.Google Scholar
  34. 34. Hersey, M. D., “Theory and Research in Lubrication: Foundations for Future Developments”, pp. 44-47, John Wiley & Sons, 1966.Google Scholar
  35. 35. “Gears – Thermal capacity, Part 2: Thermal load-carrying capacity,” ISO/TR 14179-2:2001(E), First edition 2001-08-01, ISO 2001, 2001.Google Scholar
  36. 36. Praca, M., Uehara, S., Ferreira, M., and Mian, O., “New Polymeric Coating on Sputtered Bearings for Heavy-duty Diesel Engines,” SAE Int. J. Engines 6(1):623-628, 2013, doi: 10.4271/2013-01-1724.
  37. 37. Hoppe, S. and Kantola, T., “DuroGlide® - New Generation Piston Ring Coating for Fuel-Efficient Commercial Vehicle Engines,” SAE Technical Paper 2014-01-2323, 2014, doi: 10.4271/2014-01-2323.
  38. 38. Reichert, J., and Schäfer, P., “Reduced Friction in Engine Sealing System for Truck Engines,” MTZ Worldw (2010) 71: 30. doi: 10.1007/BF03227989

Copyright information

© Springer Fachmedien Wiesbaden GmbH 2017

Authors and Affiliations

  • Neerav Abani
    • 1
    Email author
  • Michael Chiang
    • 1
  • Isaac Thomas
    • 1
  • Nishit Nagar
    • 1
  • Rodrigo Zermeno
    • 1
  • Gerhard Regner
    • 1
  1. 1.Achates Power IncSan DiegoUSA

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