The Impact of Hydrogen Enrichment on Engine Performance and Exhaust Emissions in LPG-Hydrogen Blends
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Abstract
This work explores how adding hydrogen to LPG affects the performance and emission behavior of a modified CLIO2 four-cylinder spark-ignition engine. The investigation considered three fuel compositions—pure LPG, a blend containing 30% hydrogen and 70% LPG, and a richer mixture with 60% hydrogen and 40% LPG—tested at engine speeds between 1000 and 3500 rpm. Using computational fluid dynamics (CFD) modeling, the study evaluated parameters such as brake torque (BT), brake-specific fuel consumption (BSFC), and the concentrations of nitrogen oxides (NOx) and carbon monoxide (CO) in the exhaust gases. The simulation outcomes indicated a clear improvement in engine performance with increasing hydrogen content. The 60% hydrogen blend achieved the highest torque, nearly 100 N·m at 2000–2500 rpm, corresponding to about a 25% gain compared with the baseline LPG operation. Enhanced fuel economy was also recorded for this blend, which reached a minimum BSFC of nearly 50 g/kWh at higher speeds. Although NOx formation rose at lower speeds with hydrogen addition, a declining trend was noted at elevated speeds. Furthermore, CO emissions markedly decreased as the hydrogen fraction increased, with the 60% hydrogen blend sustaining the lowest steady-state level (0.21%) relative to pure LPG (0.37%). Overall, hydrogen supplementation proved to be an effective strategy for boosting LPG engine efficiency while simultaneously mitigating pollutant emissions.
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References
Akansu, S.O. & Bayrak, M. (2011). Experimental study on a spark ignition engine fueled by CH4/H2 (70/30) and LPG. International Journal of Hydrogen Energy, 36, 9260–9266.
Bielaczyc, P., Woodburn, J. & Szczotka, A. (2014). An assessment of regulated emissions and CO2 emissions from a European light-duty CNG-fueled vehicle in the context of Euro 6 emissions regulations. Applied Energy, 117, 134–141.
Choi, G.H., Chung, Y.J. & Han, S.B. (2005). Performance and emissions characteristics of a hydrogen-enriched LPG internal combustion engine at 1400 rpm. International Journal of Hydrogen Energy, 30, 77–82.
Choi, G.H., Hu, S.B. & Chung, Y.J. (2003). The effect of hydrogen enrichment on exhaust emissions and thermal efficiency in an LPG-fueled engine. KSME International Journal, 17(8), 1196–1202.
Deb, M., Paul, A., Debroy, D., Sastry, G.R.K., Panua, R.S. & Bose, P.K. (2015). An experimental investigation of performance–emission trade-off characteristics of a CI engine using hydrogen as dual fuel. Energy, 85, 569–585.
Kacem, S.H., et al. (2016). The effect of H2 enrichment on in-cylinder flow behavior, engine performances and exhaust emissions: Case of LPG–hydrogen engine. Applied Energy, 179, 961–971.
Kamil, M. & Rahman, M.M. (2015). Performance prediction of spark-ignition engine running on gasoline–hydrogen and methane–hydrogen blends. Applied Energy, 158, 556–567.
Karamangil, M.I. (2007). Development of the autogas and LPG-powered vehicle sector in Turkey: A statistical case study of the sector for Bursa. Energy Policy, 35, 640–649.
Kawahara, N. & Tomita, E. (2009). Visualization of auto-ignition and pressure wave during knocking in a hydrogen spark-ignition engine. International Journal of Hydrogen Energy, 34, 3156–3163.
Lee, J., Lee, K., Lee, J. & Anh, B. (2014). High power performance with zero NOx emission in a hydrogen-fueled spark ignition engine by valve timing and lean boosting. Fuel, 128, 381–389.
Lee, K., Huynh, T.C. & Lee, J. (2010). A study on realization of high performance without backfire in a hydrogen-fueled engine with external mixture. International Journal of Hydrogen Energy, 35, 13078–13087.
Lim, C., Kim, D., Song, C., Kim, J., Han, J. & Cha, J.S. (2015). Performance and emission characteristics of a vehicle fueled with enriched biogas and natural gases. Applied Energy, 139, 17–29.
Liu, X., Liu, F., Zhou, L., Sun, B. & Schock, H.J. (2008). Backfire prediction in a manifold injection hydrogen internal combustion engine. International Journal of Hydrogen Energy, 33, 3847–3855.
Mariani, A., Morrone, B. & Unich, A. (2012). Numerical evaluation of internal combustion spark ignition engines performance fueled with hydrogen–natural gas blends. International Journal of Hydrogen Energy, 37, 2644–2654.
Morrone, B. & Unich, A. (2009). Numerical investigation on the effects of natural gas and hydrogen blends on engine combustion. International Journal of Hydrogen Energy, 34, 4626–4634.
Sàinz, D., Diéguez, P.M., Sopena, C., Urroz, J.C. & Gandía, L.M. (2012). Conversion of a commercial gasoline vehicle to run bi-fuel (hydrogen–gasoline). International Journal of Hydrogen Energy, 37, 1781–1789.
Sàinz, D., Diéguez, P.M., Urroz, J.C., Sopena, C., Guelbenzu, E. & Pérez-Ezcurdia, A. (2011). Conversion of a gasoline engine–generator set to be a bi-fuel (hydrogen/gasoline) electronic fuel-injected power unit. International Journal of Hydrogen Energy, 36, 13781–13792.
Sandalci, T. & Karagor, Y. (2014). Experimental investigation of the combustion characteristics, emissions and performance of hydrogen port fuel injection in a diesel engine. International Journal of Hydrogen Energy, 39, 18480–18489.
Santoso, W.B., Bakar, R.A. & Nur, A. (2013). Combustion characteristics of diesel–hydrogen dual-fuel engine at low load. Energy Procedia, 32, 3–10.
Sopena, C., Diéguez, P.M., Sainz, D., Urroz, J.C., Guelbenzu, E. & Gandía, L.M. (2010). Conversion of a commercial spark ignition engine to run on hydrogen: Performance comparison using hydrogen and gasoline. International Journal of Hydrogen Energy, 35, 1420–1429.
Verhelst, S. & Wallner, T. (2009). Hydrogen-fueled internal combustion engines. Progress in Energy and Combustion Science, 35, 490–527.
Yang, Z., Wang, L., Zhang, Q., Meng, Y. & Pei, P. (2012). Research on optimum method to eliminate backfire of hydrogen internal combustion engines based on combining postponing ignition timing with water injection of intake manifold. International Journal of Hydrogen Energy, 37, 12868–12878.