Cold Start HD FTP Test Results on Multi-Cylinder Opposed-Piston Engine Demonstrating Rapid Exhaust Enthalpy Rise to Achieve Ultra Low NOx
Published April 3, 2018 by SAE International in United States
Downloadable datasets for this paper availableAnnotation of this paper is available
The 2010 emission standards for heavy-duty diesel engines in the U.S. have established a limit for oxides of nitrogen (NOx) emissions of 0.20 g/bhp-hr., a 90% reduction from the previous emission standards. However, it has been projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with the 2010 emission standards, the upcoming National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter and ozone will not be achieved in California without further significant reductions in NOx emissions from the heavy-duty vehicle fleet. Given this, there is potential of further reduction in NOx emissions limit standards for heavy duty engines in the US. Recently there have been extensive studies and publications focusing on ultra-low NOx after treatment technologies that help achieve up to 0.02g/bhp-hr. at tailpipe .
To achieve ultra-low NOx emission levels over the composite HD FTP cycle, rapid heat energy must be provided to the diesel exhaust after-treatment system during cold start portion of the cycle, and peak NOx reduction efficiency must be maintained during the hot-start portion of cycle. Delivering this has been the challenge for conventional four-stroke heavy duty diesel engines as these are competing demands. Ultra-low NOx system solutions involving the implementation of supplemental heat sources downstream in the exhaust system comes at CO2 penalty and adds significant cost and complexity.
The Achates Power Opposed-Piston Engine design provides an ideal solution to this challenge. The opposed-piston engine has several inherent advantages over conventional four-stroke engines, like higher BTE , low BMEP and internal EGR facilitating low engine out NOx and ability to provide rapid engine out temperature rise  for emission system while maintaining low engine out NOx.
This paper highlights the results from cold-start HD FTP testing with the 4.9L Opposed-Piston Engine. The target of this testing was to evaluate the ability of the Achates Power Opposed-Piston Engine to provide rapid engine out temperature rise by operating the engine in the mode designed to deliver exhaust enthalpy, aiding fast catalyst light-off which enables early and peak NOx conversion in the exhaust after treatment system. Rapid exhaust heat and temperature rise that was delivered exceeded SCR catalyst light-off temperature thresholds (200°C) within the first 40 seconds in the cycle while controlling the engine out NOx levels.
CitationPatil, S., Ghazi, A., Redon, F., Sharp, C. et al., "Cold Start HD FTP Test Results on Multi-Cylinder Opposed-Piston Engine Demonstrating Rapid Exhaust Enthalpy Rise to Achieve Ultra Low NOx," SAE Technical Paper 2018-01-1378, 2018, https://doi.org/10.4271/2018-01-1378.
Data Sets - Support Documents
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- Sharp, C., Webb, C., Yoon, S., Carter, M. et al., “Achieving Ultra Low NOX Emissions Levels with a 2017 Heavy-Duty On-Highway TC Diesel Engine - Comparison of Advanced Technology Approaches,” SAE Int. J. Engines 10(4):1722-1735, 2017, doi:10.4271/2017-01-0956.
- Abani, N., Nagar, N., Zermeno, R., Chiang, M. et al., “Developing a 55% BTE Commercial Heavy-Duty Opposed-Piston Engine without a Waste Heat Recovery System,” SAE Technical Paper 2017-01-0638, 2017, doi:10.4271/2017-01-0638.
- Low Emissions and Rapid Catalyst Light-Off Capability for Upcoming Emissions Regulations with an Opposed-Piston, Two-Stroke Diesel Engine - Redon F., Kalebjian C., Michael Wahl - Presented at Emissions 2012, Global Automotive Management Council.
- Nagar, N., Sharma, A., Redon, F., Sukumar, B., and Walker, A. P., “Simulation and Analysis of After-Treatment Systems (ATS) for Opposed-Piston 2 stroke Engine,” presented at Emissions 2016, Troy, MI, 2016.
- Herold, R.E., Wahl, M.H., Regner, G., Lemke, J.U., and Foster, D.E., “Thermodynamic Benefits of Opposed-Piston Two-Stroke Engines,” SAE Technical Paper 2011-01-2216, 2011, doi:10.4271/2011-01-2216.
- Naik, S., Johnson, D., Fromm, L., Koszewnik, J. et al., “Achieving Bharat Stage VI Emissions Regulations While Improving Fuel Economy with the Opposed-Piston Engine,” SAE Int. J. Engines 10(1):17-26, 2017, doi:10.4271/2017-26-0056.
- Naik, S., Redon, F., Regner, G., and Koszewnik, J., “Opposed-Piston 2-Stroke Multi-Cylinder Engine Dynamometer Demonstration,” SAE Technical Paper 2015-26-0038, 2015, doi:10.4271/2015-26-0038.
- Kalebjian, C., Redon, F., and Wahl, M., “Low Emissions and Rapid Catalyst Light-Off Capability for Upcoming Emissions Regulations with an Opposed-Piston, Two-Stroke Diesel Engine”, presented at Emissions 2012 Conference.
- Redon, F., Sharma, A., and Headley, J., “Multi-Cylinder Opposed Piston Transient and Exhaust Temperature Management Test Results,” SAE Technical Paper 2015-01-1251, 2015, doi:10.4271/2015-01-1251.
- Sharma, A. and Redon, F., “Multi-Cylinder Opposed-Piston Engine Results on Transient Test Cycle,” SAE Technical Paper 2016-01-1019, 2016, doi:10.4271/2016-01-1019.