Exhaust Gas Simulation of Hydrogen–Ethanol Dual Fuel

The drawback of lean burn with ethanol is reduced power output. Lean operation of ethanol fuelled engines has additional drawbacks. Lean mixtures are hard to ignite, despite the mixture being above the low fire (point) limit of the fuel. This results in misfire, which increases unburned hydrocarbon emissions, reduces performance and wastes fuel. Hydrogen can be used in conjunction with ethanol provided it is stored separately. Mixing hydrogen with a oxygenated hydrocarbon fuel such as ethanol reduces all of these drawbacks. The low ignition energy limit of hydrogen combined with a high burning speed makes the hydrogen-ethanol mixture easier to ignite, reducing misfire and thereby improving emissions, performance and fuel economy. The current study involved generating simulation software that provides the mole fraction of each of the exhaust species when hydrogen is combusted with ethanol. The proportion of hydrogen in the hydrogen–ethanol blend affecting the mole fraction of the exhaust species is also simulated. The program code developed gave reasonably good results for the present hydrogen-ethanol dual fuel. At low and high percentages of hydrogen, and during transition between ethanol and hydrogen, the model predictions are not very clear. The best results were obtained for a combination of 80% hydrogen and 20% ethanol by volume.