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Development of Urea-SCR System for Heavy-Duty Commercial Vehicles
Technical Paper
2005-01-1860
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
In Japan there is currently a strong social demand for exhaust emissions reduction from heavy-duty diesel engines. Therefore, new Long-Term Regulation will come into effect in October 2005, setting the NOx standard at 2.0 g/kWh and the PM standard at 0.027 g/kWh. At the same time, customers always demand exceptional fuel economy from heavy-duty commercial vehicles. A urea-based Selective Catalytic Reduction (SCR) system was developed to satisfy both these demands, and will be introduced in the fall of 2004.
The operating conditions of vehicles in Japan are different from those in the US and Europe. Basically, average vehicle speeds are significantly lower. To improve the low temperature SCR performance, an oxidation catalyst was located upstream of the SCR, and an additional oxidation catalyst was located downstream of the SCR for emergency NH3 slip. The muffler size with all three catalysts was similar to a conventional muffler.
The fuel and urea water solution consumption of the system was studied and compared with the fuel consumption of a similar system equipped with EGR and a Diesel Particulate Filter (DPF) unit.
The properties of the urea water solution used here were not well known at the time of this project. Therefore, the specifications and corrosion characteristics of relevant materials were investigated and suitable materials were selected. Urea water solutions freeze at around -11 deg C, so a thawing system was also developed.
Vehicle tests were carried out at various conditions, during which no major problems arose.
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Citation
Hirata, K., Masaki, N., Ueno, H., and Akagawa, H., "Development of Urea-SCR System for Heavy-Duty Commercial Vehicles," SAE Technical Paper 2005-01-1860, 2005, https://doi.org/10.4271/2005-01-1860.Also In
Diesel Exhaust Emission Control and Modeling on CD-ROM from the SAE 2005 World Congress
Number: SP-1981CD; Published: 2005-04-11
Number: SP-1981CD; Published: 2005-04-11
References
- Havenith C. Verbeek R. P. 1997 Transient Performance of a Urea deNOx Catalyst System for Low Emissions Heavy-Duty Diesel Engines SAE Paper 970185
- Fritz N. Mathes W. Zuerbig J. Mueller R. 1999 On-Road Demonstration of NOx Emission Control for Diesel Trucks with SINOx Urea SCR System SAE Paper 1999-01-0111
- Miller W. R. Klein J. T. Mueller R. Doelling W. Zuerbig J. 2000 The Development of Urea-SCR Technology for US Heavy Duty Trucks SAE Paper 2000-01-0190
- Moser F. X. Sams T. Cartellieri W. 2001 Impact of Future Exhaust Gas Emission Legislation on the Heavy Duty Truck Engine SAE Paper 2001-01-0186