Comparison of regulated and non-regulated pollutants with iso-octane/butanol and iso-octane/ethanol blends in a port-fuel injection Spark-Ignition engine

Experimental tests were carried out on a single-cylinder port-fuel injection SI engine to quantify the potential of butanol/isooctane blends (with an alcohol concentration of 0%vol, 25%vol, 50%vol, 75%vol and 100%vol) to reduce regulated pollutants (CO, CO2, Nox and THC), and non-regulated pollutants (methane, acetylene, ethylene, benzene, acetaldehyde and formaldehyde), without deteriorating the engine performance. A comparison with results obtained for ethanol/isooctane blends is given. It was observed that the addition of alcohol results in an increase of the fuel consumption of about 30% with butanol and 60% with ethanol, but only a slight increase (about 2%) in CO2 emissions. A strong decrease in HC and Nox emissions was obtained for both alcohols. For the non-regulated pollutants, the addition of ethanol induces a reduction of up to 100% in ethylene emissions, whereas with butanol, a strong increase is observed. The addition of butanol induces a greater decrease, of up to 100%, in methane emissions than ethanol. For benzene emissions, a strong reduction is observed for both alcohols. Moreover, the addition of alcohol engenders a reduction in acetylene emissions and an increase in formaldehyde emissions, but at different levels for both alcohols. Finally, no effects or trends were distinguishable for acetaldehyde and CO emissions.