A Comprehensive Review of Natural Gas-Diesel Dual-Fuel Engines: Efficiency, Emissions, and Engine Performance

Authors

Medhat Elkelawy Prof. Dr, Eng., Mechanical Power Engineering Departments, Faculty of Engineering, Tanta University, Tanta, EgyptFollow
E. A. El Shenawy Prof. Dr., Mechanical Power Engineering Departments, Faculty of Engineering, Tanta University, Tanta, EgyptFollow
Hagar Alm-Eldin Bastawissi Prof. Dr. Eng., Department of Mechanical Power Engineering, Faculty of Engineering, Tanta University, Tanta, EgyptFollow
Mohamed Mostafa Shafey Eng, Department of Mechanical Power Engineering, Faculty of Engineering, Tanta University, Tanta, EgyptFollow

DOI

https://doi.org/10.70259/engJER.2025.921946

Abstract

Natural gas (NG) diesel dual-fuel systems have emerged as a promising advancement in internal combustion engine (ICE) technology, offering significant potential for reducing emissions, while maintaining high fuel efficiency and performance standards. This review critically examines the combustion characteristics, operational performance, emissions mitigation potential, and the engineering challenges associated with engine modifications and fuel system compatibility. Furthermore, the role of dual-fuel technology within broader global climate change mitigation strategies is explored. Extensive evidence from the literature confirms that NG-diesel dual-fuel engines can achieve substantial reductions in nitrogen oxides (NOₓ) emissions up to 53% particulate matter (PM) by over 60%, and carbon dioxide (CO₂) by 30–40% compared to conventional diesel engines. The characteristic two-stage combustion process initiated by a diesel pilot followed by NG combustion enables improvements in thermal efficiency by 5–15%, though accompanied by increased ignition delay and higher hydrocarbon (HC) and carbon monoxide (CO) emissions under high NG substitution ratios. Strategic interventions such as optimized injection timing, split injection techniques, and intake heating have been identified as effective in mitigating performance trade-offs. Looking forward, the prospects for NG-diesel dual-fuel technology are notably strong, particularly given the intensifying global emphasis on transportation decarbonization. Future research is anticipated to focus on advanced combustion control strategies utilizing artificial intelligence and real-time emissions feedback, fuel quality optimization with biomethane and hydrogen-enriched natural gas, the development of dedicated dual-fuel engine architectures, and the design of emissions aftertreatment systems tailored for dual-fuel operation. Additional priorities include comprehensive durability studies, knock mitigation at high substitution ratios, techno-economic and life-cycle analyses under real-world conditions, and the expansion of CNG/LNG refueling infrastructure supported by progressive policy initiatives.

Recommended Citation

Elkelawy, Medhat Prof. Dr, Eng.; El Shenawy, E. A. Prof. Dr.; Bastawissi, Hagar Alm-Eldin Prof. Dr. Eng.; and Shafey, Mohamed Mostafa Eng (2025) "A Comprehensive Review of Natural Gas-Diesel Dual-Fuel Engines: Efficiency, Emissions, and Engine Performance," Journal of Engineering Research: Vol. 9: Iss. 2, Article 11.
DOI: https://doi.org/10.70259/engJER.2025.921946
Available at: https://digitalcommons.aaru.edu.jo/erjeng/vol9/iss2/11