CO2 emissions from a spark ignition engine operating on natural gas–hydrogen blends (HCNG)

Applied Energy, Volume 101, January 2013, Pages 112–120
Sustainable Development of Energy, Water and Environment Systems
CO2 emissions from a spark ignition engine operating on natural gas–hydrogen blends (HCNG)
Emilio Navarro (a), Teresa J. Leo (b), Roberto Corral (b)
a Dept. Motopropulsión y Termofluidodinámica, E.T.S.I. Aeronáuticos, Universidad Politécnica de Madrid, Madrid, Spain
b Dept. Sistemas Oceánicos y Navales, E.T.S.I. Navales, Universidad Politécnica de Madrid, Madrid, Spain
Abstract
Authors evaluate the emissions and performance of a spark ignition engine fuelled by pure natural gas, pure hydrogen, and various blends of hydrogen and natural gas (HCNG). Increasing the hydrogen fraction leads to variations in cylinder pressure and CO2 emissions. Researchers employ a combustion model based on thermodynamic equations, considering separate zones for burned and unburned gases.
Results reveal that the maximum cylinder pressure rises as the fraction of hydrogen in the blend increases. The presence of hydrogen in the blend leads to a decrease in CO2 emissions. Due to the properties of hydrogen, leaner fuel–air mixtures can be used along with the appropriate spark timing.  This results in improved engine emissions with no loss of performance.
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