Research Article

Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study

Volume: 6 Number: 4 October 26, 2026

Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study

Abstract

Hydrogen is widely recognized as a promising zero-carbon fuel for internal combustion engines due to its zero carbon emissions, high laminar flame speed, and wide flammability limits. In dual-fuel compression ignition engines, substituting part of the diesel fuel with hydrogen can significantly reduce carbon-based emissions while maintaining or improving ther-mal efficiency. This study investigates the combined effects of hydrogen substitution ratio (HSR) and equivalence ratio (Φ) on combustion characteristics, engine performance, and emissions in a diesel-hydrogen dual-fuel engine. Three HSR levels (50, 70, and 90) are examined across equivalence ratios ranging from 0.5 to 0.8. A three-dimensional computational fluid dynamics (CFD) model is developed using ANSYS Forte. The model employs an Eulerian-Lagrangian framework, incorpo-rating the unsteady Reynolds-averaged Navier–Stokes (URANS) equations for flow resolution and the G-equation for turbu-lent flame propagation. Spray breakup dynamics are modeled using the Kelvin–Helmholtz/Rayleigh–Taylor approach, while turbulence is captured with the RNG k-ε model. Results indicate that increasing both the HSR and equivalence ratio reduces CO₂ emissions. At HSR 70, unburned hydrocarbon (UHC) emissions decrease by up to 82% as Φ increases from 0.5 to 0.8. Furthermore, the indicated specific fuel consumption (ISFC) decreases, particularly at high HSR, reflecting improved fuel economy. These findings highlight the potential of diesel-hydrogen dual-fuel operation for achieving cleaner and more efficient engine performance.

Keywords

References

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Details

Primary Language

English

Subjects

Energy Generation, Conversion and Storage (Excl. Chemical and Electrical)

Journal Section

Research Article

Publication Date

October 26, 2026

Submission Date

April 25, 2026

Acceptance Date

August 20, 2026

Published in Issue

Year 2026 Volume: 6 Number: 4

APA
Hamdi, T., Molima, S., José Hernández, J., Rodriguez-Fernandez, J., M. Domínguez, V., & Chrigui, M. (2026). Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study. Engineering Perspective, 6(4), 638-649. https://doi.org/10.64808/engineeringperspective.1927683
AMA
1.Hamdi T, Molima S, José Hernández J, Rodriguez-Fernandez J, M. Domínguez V, Chrigui M. Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study. engineeringperspective. 2026;6(4):638-649. doi:10.64808/engineeringperspective.1927683
Chicago
Hamdi, Takwa, Samuel Molima, Juan José Hernández, Jose Rodriguez-Fernandez, Victor M. Domínguez, and Mouldi Chrigui. 2026. “Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study”. Engineering Perspective 6 (4): 638-49. https://doi.org/10.64808/engineeringperspective.1927683.
EndNote
Hamdi T, Molima S, José Hernández J, Rodriguez-Fernandez J, M. Domínguez V, Chrigui M (October 1, 2026) Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study. Engineering Perspective 6 4 638–649.
IEEE
[1]T. Hamdi, S. Molima, J. José Hernández, J. Rodriguez-Fernandez, V. M. Domínguez, and M. Chrigui, “Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study”, engineeringperspective, vol. 6, no. 4, pp. 638–649, Oct. 2026, doi: 10.64808/engineeringperspective.1927683.
ISNAD
Hamdi, Takwa - Molima, Samuel - José Hernández, Juan - Rodriguez-Fernandez, Jose - M. Domínguez, Victor - Chrigui, Mouldi. “Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study”. Engineering Perspective 6/4 (October 1, 2026): 638-649. https://doi.org/10.64808/engineeringperspective.1927683.
JAMA
1.Hamdi T, Molima S, José Hernández J, Rodriguez-Fernandez J, M. Domínguez V, Chrigui M. Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study. engineeringperspective. 2026;6:638–649.
MLA
Hamdi, Takwa, et al. “Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study”. Engineering Perspective, vol. 6, no. 4, Oct. 2026, pp. 638-49, doi:10.64808/engineeringperspective.1927683.
Vancouver
1.Takwa Hamdi, Samuel Molima, Juan José Hernández, Jose Rodriguez-Fernandez, Victor M. Domínguez, Mouldi Chrigui. Combustion and Emissions Characteristics of a Dual-Fuel CI Engine under Varying Hydrogen Energy and Equivalence Ratios: A Computational Study. engineeringperspective. 2026 Oct. 1;6(4):638-49. doi:10.64808/engineeringperspective.1927683

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