This study proposed a new low-temperature premixed combustion mode to achieve the simultaneous reduction of NOx and soot emissions in a volume production diesel engine of CA6DF by reconstructing key systems. Some developments of this diesel engine are as follows. A straight port and large diameter combustion chamber of a low compression ratio was developed. Inlet ports of a high induction swirl ratio were developed. A cooled EGR was developed. Especially, an ultra-multihole (UMH) nozzle was developed. It has two layers of injection holes and a large flow area. Two sprays of the upper and under layers meet in the space of the combustion chamber. The results showed that the operation range of this diesel engine to achieve the better low-temperature premixed combustion is as follows. The speed can cover from the idle speed to the rated speed. The load can reach to 50% of the full load of the corresponding external characteristics speed. The NOx and soot emissions of this operation range are simultaneously largely reduced, even by 80%–90% at most test cases, while keeping the brake-specific fuel consumption (BSFC) from being significantly deteriorated. 1. Introduction The conventional diesel engine combustion is dominated by the heterogeneous mixture diffusion combustion. The flame front is the diffusion flame with the stoichiometric equivalence ratio mixture. Thus, the maximum combustion temperature is very high, which is beneficial to NOx generation. The inherent characteristic of the conventional diesel engine combustion determines the existence of a minimum NOx emissions value [1]. And the occurrence of locally low oxygen concentration zones is a precursor for the formation of soot. Therefore, the ideal excess air coefficient of the conventional diesel premixed combustion should meet with , or in order to prevent the formation of soot and a large amount of NOx emissions [2].Thus, it is necessary to explore a new way to change a heterogeneous diesel-air mixture, stoichiometric equivalence ratio mixture, and diffusion flame properties in order to meet increasingly stringent emissions regulations. The low-temperature premixed combustion is just a new combustion mode that can reduce NOx and soot emissions simultaneously [3–11]. In recent years, homogeneous charge compression ignition (HCCI) combustion, umbrella spray combustion, modulated kinetic combustion, multiple stage diesel combustion, homogeneous charge diesel combustion, multiple pulse injection HCCI combustion, and low-temperature combustion, all belong to this category. Their common target is to
References
[1]
D. W. Dicked, et al., “NOx control in heavy-duty diesel engines—what is the Limit?” SAE Paper 980174, 1998.
[2]
C. Arcounmanis, et al., “Mixture formation and combustion in the D.I. diesel engine,” SAE Paper 972681, 1997.
[3]
S. Kimura, O. Aoki, H. Ogawa, and S. Muranaka, “New combustion concept for ultra-clean and high-efficiency small DI diesel engines,” SAE Paper 1999-01-3681, 1999.
[4]
S. Kimura, O. Aoki, Y. Kitahara, and A. Eiji, “Ultra-clean combustion technology combining a low-temperature and PremiXed Combustion Concept for Meeting Future Emission Standards,” SAE Paper 2001-01-0200, 2001.
[5]
T. J. Jacobs and D. N. Assanis, “The attainment of premixed compression ignition low-temperature combustion in a compression ignition direct injection engine,” Proceedings of the Combustion Institute, vol. 31, pp. 2913–2920, 2007.
[6]
T. J. Jacobs, S. V. Bohac, D. N. Assanis, and P. G. Szymkowicz, “Lean and Rich Premixed Compression ignition combustion in a light-duty diesel engine,” SAE 2005-01-0166, 2005.
[7]
K. Akihama, Y. Takatori, K. Inagaki, and S. Sasaki, “Mechanism of the smokeless rich diesel combustion by reducing temperature,” SAE 2001-01-0655, 2001.
[8]
D. Choi, P. C. Miles, H. Yun, and R. D. Reitz, “A parametric study of low-temperature, late-injection combustion in a HSDI diesel engine,” JSME International Journal, Series B, vol. 48, no. 4, pp. 656–664, 2005.
[9]
R. H. Stanglmaier and C. E. Roberts, “Homogeneous charge compression ignition (HCCI): benefit, compromises, and future engine applications,” SAE Paper 1999-01-3682, 1999.
[10]
F. Zhao, T. Asmus, D. Assanis, J. Dec, J. Eng, and P. Najt, “Homogeneous charge compression ignition (HCCI) engines,” SAE Paper, 2003.
[11]
K. Kawamoto and T. Araki, “Combination of combustion concept and fuel property for ultra-clean di diesel,” SAE Paper 2004-01-1868, 2004.
[12]
S. Simescu, S. B. Fiveland, and L. G. Dodge, “An experimental investigation of PCCI-DI combustion and emissions in a heavy-duty diesel engine,” SAE 2003-01-0345, 2003.
[13]
K. Okude, et al., “Premixed compression ignition (PCI) combustion for simultaneously reduction NOx and soot in diesel engine,” SAE Paper 2004-01-1907, 2007.
[14]
C. Noehre, M. Andersson, B. Johansson, and A. Hultqvist, “Characterization of partially premixed combustion,” SAE Paper 2006-01-3412, 2006.
[15]
B. Kobayashi, S. Najima, M. Mikami, N. Kojima, and T. Kanda, “Effects of fuel volatility on combustion characteristics of PCCI diesel engine,” SAE Paper 2007-01-1862, 2007.
[16]
M. Y. Kim and C. S. Lee, “Effect of a narrow fuel spray angle and a dual injection configuration on the improvement of exhaust emissions in a HCCI diesel engine,” Fuel, vol. 86, no. 17-18, pp. 2871–2880, 2007.
[17]
J. Ma, X. Lü, L. Ji, and Z. Huang, “An experimental study of HCCI-DI combustion and emissions in a diesel engine with dual fuel,” International Journal of Thermal Sciences, vol. 47, no. 9, pp. 1235–1242, 2008.
[18]
M. Zheng, G. T. Reader, and J. G. Hawley, “Diesel engine exhaust gas recirculation—a review on advanced and novel concepts,” Energy Conversion and Management, vol. 45, no. 6, pp. 883–900, 2004.
[19]
B. Challen and R. Baranescu, Diesel Engine Reference Book, Butterworth-Heinemann, 2nd edition, 1999.
[20]
X. Miao, X. Qiao, X. Wang, et al., “Study on ultramultihole nozzle fuel injection and diesel combustion,” Energy and Fuels, vol. 23, no. 2, pp. 740–743, 2009.
[21]
N. Shimazaki, T. Tsurushima, and T. Nishimura, “Dual mode combustion concept With premixed diesel combustion by direct injection near top dead center,” SAE Paper 2003-01-0742, 2003.
[22]
S. Marcus, K. Max, K. Peter, and L. Alfred, “Optical investigations on partially premixed diesel combustion for different operating parameters,” SAE paper 2008-01-0041, 2008.
[23]
S. Inderpal, Z. Lurun, D. Minq-Chia, W. Bryzik, and A. Naeim, “Effect of nozzle hole geometry on a Hsdi diesel engine- out emissions,” SAE paper 2003-01-0704, 2003.
