International Scientific Journal


It has been shown that using fuel additives play an important role in enhancing the combustion characteristics in terms of efficiency and emissions. In addition, free piston engines have shown capable in reducing energy losses and presenting more efficient and reliable engines. In this context, the objective of the present work is to investigate the effect of using hydrogen as a fuel additive in natural gas homogeneous charge compression ignition free piston engine. To this aim, two models have been iteratively coupled: the combustion model that is used to calculate the heat release of the combustion and the scavenging model that is employed to determine the in-cylinder mixture state after scavenging in terms of its homogeneity and species mass fractions and to obtain the finial pressure and temperature of the in-cylinder mixture. In the former model, the 0-D approach through Cantera toolkit has been considered due to the fact that homogeneous charge compression ignition combustion is very rapid and the fuel-air mixture is well-homogenous, whereas in the latter model, 3-D-CFD approach through AN-SYS FLUENT software is considered to ensure precise calculations of the species exchange at the end of each engine cycle. The effect of hydrogen as a fuel additive has been quantified in terms of the combustion characteristics (e. g., ignition delay, heat release rate, engine overall efficiency and emissions, etc.). It has been shown that hydrogen addition reduces ignition delay time, decreases the in-cylinder peak pressure, while allowing the engine to operate with higher mechanical efficiency as it has high heat release rate, increases the NOx emission levels of the engine, but decreases the CO levels
PAPER REVISED: 2019-02-17
PAPER ACCEPTED: 2019-02-22
CITATION EXPORT: view in browser or download as text file
  1. Clark, N, et al, Operation of a Small Bore Two-Stroke Linear Engine, Clymer, NY, 1998.
  2. Ba, H, et al, Simulation study of si-hcci transition in a two-stroke free piston engine fuelled with propane, SAE Technical Paper, no. 2014-01-1104 (2014), 2014.
  3. Jia, et al, Development and validation of a free-piston engine generator numerical model, Energy Conversion and Management, vol. 91, , 2015. pp. 333-341
  4. Charalambides, A, Homogeneous Charge Compression Ignition (HCCI) Engines, Advances in Internal Combustion Engines and Fuel Technologies, 2013.
  5. Haraldsson, G ,et al, Hcci combustion phasing in a multi cylinder engine using variable compression ratio, SAE Technical Paper, no. 2002-01-2858 (2002), 2002.
  6. Ying, Y and Liu, D, Detailed influences of chemical effects of hydrogen as fuel additive on methane flame, international journal of hydrogen energy , vol. 40, , 2015. pp. 3777-3788
  7. Ma, F, et al, Effects of hydrogen addition on cycle-by-cycle variations in a lean burn natural gas spark-ignition engine, International Journal of Hydrogen Energy, vol. 33, no. 2, , 2008. pp. 823-831
  8. Dillon, A, et al ,Storage of hydrogen in single-walled carbon nanotubes, Nature, vol. 386, pp. 377-379, 1997.
  9. Yap, D et al, Effect of Hydrogen Addition on Natural Gas HCCI Combustion, SAE Technical Paper , no. 2004-01-1972, 2004.
  10. Askari, H et al, Effect of Hydrogen Addition to Natural Gas on Homogeneous Charge Compression Ignition Combustion Engines Performance and Emissions Using a Thermodynamic Simulation, International Journal of Automotive Engineering, vol. 1, no. 2, pp. 105-114, 2011.
  11. Guo, H and Neill, W, The effect of hydrogen addition on combustion and emission characteristics of an n-heptane fuelled HCCI engine, International journal of hydrogen energy, vol. 38, , 2013. pp. 111429-11437
  12. Hu, E et al, Study on the effect of hydrogen addition to dimethyl ether homogeneous charge compression ignition combustion engine, JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY , vol. 7, 2015.
  13. Hammond, Z et al ,Effect of hydrogen peroxide addition to methane fueled homogeneous charge compression ignition engines through numerical simulations, International Journal of Engine Research, vol. 17, no. 2, , 2016. pp. 1-12
  14. D. Cantera, "Cantera," 2011.
  15. Smith, G et al, GRI-MECH 3.0," URL, 2008.
  16. Blair, G, Design and simulation of two-stroke engines, Warrendale, PA : Society of Automotive Engineers, 1996.
  17. Chang, J et al, New Heat Transfer Correlation for An HCCI ENgine Derived From Measurments of Instantaneous Surface Heat Flux, SAE Technical Paper, no. 2004-01-2996, 2004.
  18. Mao, J et al, Multi-dimensional scavenging analysis of a free-piston linear alternator based on numerical simulation, Applied Energy, vol. 88, no. 4, 2011. pp. 1140-1152,
  19. Van Blarigan, P et al, Homogeneous Charge Compression Ignition with a Free Piston; A New Approach to Ideal Otto Cycle Performance, SAE Technical Paper , 1998.
  20. Alrbai, M et al, Impact of Exhaust Gas Recirculation on Performance and Emissions of Free-Piston Electrical Generator Fueled by DME, Journal of energy engineering , vol. 144, no. 3, 2018.
  21. Heywood, J, Internal Combustion Engine Fundamentals, McGraw-Hill Education, 1988.

© 2022 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence