Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions

Kamran Poorghasemi; R. Khoshbakhti Saray; Hamit Solmaz; Seyed Mohammad Mousavi; Alborz Zehni

doi:10.64808/engineeringperspective.1802746

Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions

Abstract

Nowadays, low temperature combustion is a promising concept to implement in conventional internal combustion en-gines, as it provides lower emissions and higher thermal efficiency. In the current work, the combustion process of an NG/diesel Reactivity Controlled Combustion Ignition (RCCI) engine was investigated using a coupled 3D-CFD/chemical ki-netics framework. The reduced chemical kinetics mechanism containing 57 species and 190 reactions was utilized to simu-late the combustion of blended fuels. The results show that increasing premixed ratio (PR) (from 75% to 97%), while keeping constant the total input energy in RCCI engine, delays start of combustion (SOC) and CA50 and causes extended burning duration of diesel. In addition, the duration of methane combustion reduces in lower PRs in comparison with higher PRs. When dealing with injection timing, advancing the diesel injection (SOI) until specific value advances the SOC, but after-ward retards the SOC. In fact, burning duration for early injection of diesel increases (from 4.2 crank angle degree to 7.4 crank angle degree) while burning duration of methane decreases (from 10.3 crank angle degree to 5.2 crank angle degree). By further advancing SOI timing, combustion efficiency decreases (from 87.5% to 82.8%) while gross indicated efficiency increases (from 40% to 43%). However, HC and CO emissions increase by earlier SOI timing while NOx emissions decrease.

Keywords

References

1. Poorghasemi, K., Khoshbakhti Saray, R., Ansari, E., Mousavi, S. M., & Zehni, A. (2022). Statistical analysis on the effect of pre-mixed ratio, EGR, and diesel fuel injection parameters on the performance and emissions of a NG/Diesel RCCI engine using a DOE method. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 236(2–3), 460–473. https://doi.org/10.1177/09544070211015478
2. Nagareddy, S., Rajeswaran, S. S., Jaganathan, D., Subramanian, V. P. B., & Neelakandan, V. (2025). Turbocharged Six-Cylinder Direct Injection Hydrogen Fueled Spark Ignition Engine Combustion and NOx Control Model. Engineering Perspective, 4(3), 100-110. https://doi.org/10.29228/eng.pers.82203
3. Kethudaoglu, G., Aktaş, F., Karaaslan, S., & Dinler, N. (2024). 0/1 and 3-dimensional cold flow analysis of a diesel engine: A case study. International Journal of Automotive Science and Technology, 8(1), 142–149. https://doi.org/10.30939/ijastech.1384376
4. Türkcan, Ö., & Polat, S. (2025). Combustion and Emission Behaviour of a HCCI Wankel Engine Across Lambda Variations: Insights for Future Aviation-Oriented Rotary Engine Concepts. International Journal of Automotive Science And Technology, 9(4), 626-636. https://doi.org/10.30939/ijastech..1821778
5. Çelik, A., & Kunt, M. A. (2026). A Study on Predicting Engine Performance Outputs by Machine Learning Algorithms in a Single Cylinder HCCI Engine. Engineering Perspective, (1), 57-68. https://doi.org/10.64808/engineeringperspective.1782349
6. Inagaki, K., Fuyuto, T., Nishikawa, K., Nakakita, K., & Sakata, I. (2006). Dual-fuel PCI combustion controlled by in-cylinder stratification of ignitability. SAE Technical Paper No. 2006-01-0028. https://doi.org/10.4271/2006-01-0028
7. Bessonette, P. W., Schleyer, C. H., Duffy, K. P., Hardy, W. L., & Liechty, M. P. (2007). Effects of fuel property changes on heavy-duty HCCI combustion. SAE Technical Paper No. 2007-01-0191. https://doi.org/10.4271/2007-01-0191
8. Kokjohn, S., Hanson, R., Splitter, D., & Reitz, R. D. (2010). Experiments and modeling of dual-fuel HCCI and PCCI combustion using in-cylinder fuel blending. SAE International Journal of Engines, 2(2), 24–39. https://doi.org/10.4271/2009-01-2647

9. Splitter, D., Kokjohn, S., Rein, K., Hanson, R., et al. (2010). An optical investigation of ignition processes in fuel reactivity controlled PCCI combustion. SAE International Journal of Engines, 3(1), 142–162. https://doi.org/10.4271/2010-01-0345
10. Splitter, D., Hanson, R., Kokjohn, S. L., & Reitz, R. D. (2010). Improving engine performance by optimizing fuel reactivity with a dual-fuel PCCI strategy. THIESEL Conference on Thermo and Fluid Dynamic Processes in Diesel Engines.
11. Reitz, R. D., Hanson, R., Splitter, D., & Kokjohn, S. L. (2010). Engine combustion control via fuel reactivity stratification. University of Wisconsin WARF Patent Application, P100054US.
12. Kokjohn, S. L., & Reitz, R. D. (2010). Characterization of dual-fuel PCCI combustion in a light-duty engine. International Multidimensional Engine Modeling User’s Group Meeting.
13. Şahin, F., Halis, S., Yıldırım, E., Altın, M., Balaban, F., Solmaz, H., & Yücesu, H. S. (2022). Effects of premixed ratio on engine operation range and emissions of a reactivity controlled compression ignition engine. SAE International Journal of Fuels and Lubricants, 16, 169–179.
14. Halis, S., Solmaz, H., Polat, S., & Yücesu, H. S. (2023). Numerical investigation of a reactivity-controlled compression ignition engine fueled with n-heptane and iso-octane. Sustainability, 15(13), 10406. https://doi.org/10.3390/su151310406
15. Halis, S., Solmaz, H., Polat, S., & Yücesu, H. S. (2022). Numerical study of the effects of lambda and injection timing on RCCI combustion mode. International Journal of Automotive Science and Technology, 6(2), 120–126. https://doi.org/10.30939/ijastech..1105470
16. Bahrami, S., Poorghasemi, K., Solmaz, H., Calam, A., & Ipci, D. (2021). Effect of nitrogen and hydrogen addition on performance and emissions in reactivity controlled compression ignition. Fuel, 292, 120330. https://doi.org/10.1016/j.fuel.2021.120330
17. Curran, S., et al. (2013). Efficiency and emissions mapping of RCCI in a light-duty diesel engine. SAE Technical Paper No. 2013-01-0289. https://doi.org/10.4271/2013-01-0289
18. Yang, B., Yao, M., et al. (2014). Experimental and numerical study on different dual-fuel combustion modes fuelled with gasoline and diesel. Applied Energy, 113, 722–733. https://doi.org/10.1016/j.apenergy.2013.08.074
19. Nieman, D., Dempsey, A., & Reitz, R. (2012). Heavy-duty RCCI operation using natural gas and diesel. SAE International Journal of Engines, 5(2), 270–285. https://doi.org/10.4271/2012-01-0379
20. Doosje, E., Willems, F., & Baert, R. (2014). Experimental demonstration of RCCI in heavy-duty engines using diesel and natural gas. SAE Technical Paper No. 2014-01-1318. https://doi.org/10.4271/2014-01-1318
21. Walker, N. R., et al. (2015). Natural gas for high load dual-fuel reactivity controlled compression ignition in heavy-duty engines. Journal of Energy Resources Technology, 137(4), 042202. https://doi.org/10.1115/1.4030110
22. Zoldak, P., Sobiesiak, A., Bergin, M., & Wickman, D. (2014). Computational study of reactivity controlled compression ignition (RCCI) combustion in a heavy-duty diesel engine using natural gas. SAE Technical Paper No. 2014-01-1321. https://doi.org/10.4271/2014-01-1321
23. Zoldak, P., Sobiesiak, A., Wickman, D., & Bergin, M. (2015). Combustion simulation of dual fuel CNG engine using direct injection of natural gas and diesel. SAE International Journal of Engines, 8(2), 846–858. https://doi.org/10.4271/2015-01-0851
24. Min, X., Cheng, W., Li, Z., Zhang, H., An, T., & Meng, Z. (2016). Pre-injection strategy for pilot diesel compression ignition natural gas engine. Applied Energy, 179, 1185–1193.
25. Dahodwala, M., Joshi, S., Koehler, E., & Franke, M. (2014). Investigation of diesel and CNG combustion in a dual fuel regime and as an enabler to achieve RCCI combustion. SAE Technical Paper No. 2014-01-1308. https://doi.org/10.4271/2014-01-1308
26. Dahodwala, M., Joshi, S., Koehler, E., Franke, M., & Tomazic, D. (2015). Experimental and computational analysis of diesel-natural gas RCCI combustion in heavy-duty engines. SAE Technical Paper No. 2015-01-0849. https://doi.org/10.4271/2015-01-0849
27. Paykani, A., Kakaee, A. H., Rahnama, P., & Reitz, R. D. (2012). Effects of diesel injection strategy on natural gas/diesel reactivity controlled compression ignition combustion. Energy, 90, 814–826.
28. Mousavi, S. M., Khoshbakhti Saray, R., Poorghasemi, K., & Maghbouli, A. (2016). A numerical investigation on combustion and emission characteristics of a dual-fuel engine at part load condition. Fuel, 166, 309–319. https://doi.org/10.1016/j.fuel.2015.10.052
29. Mousavi, S. M., Khoshbakhti Saray, R., Bahlouli, K., Poorghasemi, K., Maghbouli, A., & Sadeghlu, A. (2019). Effects of pilot diesel injection strategies on combustion and emission characteristics of dual-fuel engines at part load conditions. Fuel, 258, 116153. https://doi.org/10.1016/j.fuel.2019.116153
30. Bahlouli, K., Atikol, U., Khoshbakhti Saray, R., & Mohammadi, V. (2014). A reduced mechanism for predicting the ignition timing of a fuel blend of natural gas and n-heptane in HCCI engine. Energy Conversion and Management, 79, 85–96. https://doi.org/10.1016/j.enconman.2013.10.020
31. Poorghasemi, K., Khoshbakhti Saray, R., Bahlouli, K., & Zehni, A. (2016). 3D CFD simulation of a natural gas fuelled HCCI engine with employing a reduced mechanism. Fuel, 182, 816–830.
32. Kokjohn, S. L., & Reitz, R. D. (2013). Reactivity controlled compression ignition and conventional diesel combustion: A comparison of methods to meet light-duty NOx and fuel economy targets. International Journal of Engine Research, 14(5), 452–468. https://doi.org/10.1177/1468087413476032
33. Rahimi, A., Fatehifar, E., & Khoshbakhti Saray, R. (2010). Development of an optimized chemical kinetic mechanism for homogeneous charge compression ignition combustion of a fuel blend of n-heptane and natural gas using a genetic algorithm. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 224(9), 1141–1159. https://doi.org/10.1243/09544070JAUTO1343
34. Amsden, A. A. (1997). KIVA-3V: A block-structured KIVA program for engines with vertical or canted valves (Report No. LA-13313-MS).
35. Kee, R. J., Rupley, F. M., & Miller, J. A. (1989). CHEMKIN-II: A FORTRAN chemical kinetics package for the analyses of gas phase chemical kinetics (Sandia Report No. SAND 89-8009).
36. Agarwal, A., & Assanis, D. (1998). Multi-dimensional modelling of natural gas ignition under compression ignition conditions using detailed chemistry. SAE Technical Paper No. 980136. https://doi.org/10.4271/980136
37. Han, Z., & Reitz, R. D. (1995). Turbulence modeling of internal combustion engines using RNG κ-ε models. Combustion Science and Technology, 106, 267–295. https://doi.org/10.1080/00102209508907782
38. Reitz, R. D. (1987). Modeling atomization processes in high-pressure vaporization spray. Atomization and Spray Technology, 3, 309–337.
39. Hosseini, V., & Checkel, M. D. (2006). Using reformer gas to enhance HCCI combustion of CNG in a CFR engine. SAE Technical Paper No. 2006-01-3247.
40. Handford, D., & Checkel, M. D. (2008). Direct injection assisted HCCI combustion of pre-mixed natural gas. FISITA Student Congress, F2008-SC-007.
41. Handford, D. (2009). Direct injection assisted HCCI combustion of natural gas (Master’s thesis). University of Alberta.
42. Mack, J. H., Flowers, D. L., Buchholz, B. A., & Dibble, R. W. (2004). Investigation of HCCI combustion of diethyl ether and ethanol mixtures using carbon 14 tracing and numerical simulations. Proceedings of the Combustion Institute, 30(2), 2693–2700. https://doi.org/10.1016/j.proci.2004.08.136
43. Kokjohn, S., Hanson, R., Splitter, D., & Reitz, R. D. (2011). Fuel reactivity controlled compression ignition (RCCI): A pathway to controlled high-efficiency clean combustion. International Journal of Engine Research, 12(3), 209–226. https://doi.org/10.1177/1468087411401548
44. ANSYS Inc. (n.d.). Introduction to ANSYS ICEM CFD Hexa. http://www.ansys.com/services/training-center/platform/introduction-to-ansys-icem-cfd-hexa
45. Eng, J. A. (2002). Characterization of pressure waves in HCCI combustion. SAE Technical Paper No. 2002-01-2859. https://doi.org/10.4271/2002-01-2859
46. Kokjohn, S., Hanson, R., Splitter, D., Kaddatz, J., & Reitz, R. D. (2011). Fuel reactivity controlled compression ignition (RCCI) combustion in light- and heavy-duty engines. SAE Technical Paper No. 2011-01-0357. https://doi.org/10.4271/2011-01-0357
47. Reitz, R. D., & Duraisamy, G. (2015). Review of high efficiency and clean reactivity controlled compression ignition (RCCI) combustion in internal combustion engines. Progress in Energy and Combustion Science, 46, 12–71. https://doi.org/10.1016/j.pecs.2014.05.003
48. Opat, R., Ra, Y., Krieger, R., Reitz, R. D., Foster, D. E., Durrett, R. P., & Siewert, R. M. (2007). Investigation of mixing and temperature effects on HC/CO emissions for highly dilute low temperature combustion in a light duty diesel engine. SAE Technical Paper No. 2007-01-0193. https://doi.org/10.4271/2007-01-0193
49. Bidarvatan, M., & Shahbakhti, M. (2014). Integrated HCCI engine control based on a performance index. Journal of Engineering for Gas Turbines and Power, 136(10), 101601. https://doi.org/10.1115/1.4027279

Details

Primary Language

English

Subjects

Automotive Combustion and Fuel Engineering

Journal Section

Research Article

Authors

Kamran Poorghasemi This is me
0000-0002-4838-749X
Iran

R. Khoshbakhti Saray This is me
0000-0003-1567-545X
Iran

Hamit Solmaz ^*
0000-0003-0689-6824
Türkiye

Seyed Mohammad Mousavi This is me
0000-0002-6026-584X
Canada

Alborz Zehni This is me
0000-0003-2308-5564
Iran

Publication Date

February 12, 2026

Submission Date

October 13, 2025

Acceptance Date

December 11, 2025

Published in Issue

Year 2026 Volume: 6 Number: 1

DOI

https://doi.org/10.64808/engineeringperspective.1802746

IZ

https://izlik.org/JA26UL23NB

Cite

RIS / Bibtex

APA

Poorghasemi, K., Saray, R. K., Solmaz, H., Mousavi, S. M., & Zehni, A. (2026). Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions. Engineering Perspective, 6(1), 69-82. https://doi.org/10.64808/engineeringperspective.1802746

AMA

1.Poorghasemi K, Saray RK, Solmaz H, Mousavi SM, Zehni A. Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions. engineeringperspective. 2026;6(1):69-82. doi:10.64808/engineeringperspective.1802746

Chicago

Poorghasemi, Kamran, R. Khoshbakhti Saray, Hamit Solmaz, Seyed Mohammad Mousavi, and Alborz Zehni. 2026. “Multi-Dimensional 3D-CFD Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions”. Engineering Perspective 6 (1): 69-82. https://doi.org/10.64808/engineeringperspective.1802746.

EndNote

Poorghasemi K, Saray RK, Solmaz H, Mousavi SM, Zehni A (February 1, 2026) Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions. Engineering Perspective 6 1 69–82.

IEEE

[1]K. Poorghasemi, R. K. Saray, H. Solmaz, S. M. Mousavi, and A. Zehni, “Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions”, engineeringperspective, vol. 6, no. 1, pp. 69–82, Feb. 2026, doi: 10.64808/engineeringperspective.1802746.

ISNAD

Poorghasemi, Kamran - Saray, R. Khoshbakhti - Solmaz, Hamit - Mousavi, Seyed Mohammad - Zehni, Alborz. “Multi-Dimensional 3D-CFD Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions”. Engineering Perspective 6/1 (February 1, 2026): 69-82. https://doi.org/10.64808/engineeringperspective.1802746.

JAMA

1.Poorghasemi K, Saray RK, Solmaz H, Mousavi SM, Zehni A. Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions. engineeringperspective. 2026;6:69–82.

MLA

Poorghasemi, Kamran, et al. “Multi-Dimensional 3D-CFD Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions”. Engineering Perspective, vol. 6, no. 1, Feb. 2026, pp. 69-82, doi:10.64808/engineeringperspective.1802746.

Vancouver

1.Kamran Poorghasemi, R. Khoshbakhti Saray, Hamit Solmaz, Seyed Mohammad Mousavi, Alborz Zehni. Multi-Dimensional 3D-CFD/Chemical-Kinetics Modeling of Natural Gas–Diesel RCCI Engines: Combustion Phasing, Efficiency and Emissions. engineeringperspective. 2026 Feb. 1;6(1):69-82. doi:10.64808/engineeringperspective.1802746

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