Variation of Engine Performance and Emissions using Ethanol Blends

The limited fossil fuel resources along with the increased public concerns about pollution levels have increased the need for alternative fuels for use in internal combustion engines. This study is to investigate the variation of the engine performance and exhaust emissions of a spark ignition engine. A spark ignition engine running with gasoline and gasoline blended E5, E10 and E20 (E5, that mean 5% of ethanol and 95% of gasoline by volume). Effects of engine speeds of 1000, 1500, 2000, 2500, 3000 and 3500 rpm and throttle valve 25%, 50%, 75% and full throttle, on the engine performance and the emission concentrations are investigated. Improved engine performance and reduced emissions are observed with ethanol addition.
The results showed that the engine brake torque was increased with engine speed. Ethanol blends produced higher torque, compared with gasoline. Lowest brake thermal efficiencies are found for gasoline, for all speeds. All blends showed recognised increase in the brake thermal efficiency with the speed. Also the results showed that the emissions level of blends was reduced the Carbone monoxide CO, oxides of nitrogen NO¬¬x and unburned hydrocarbons concentrations. Blends with maximum alcohol content E20 produced lowest CO and HC emissions, camper with the other fuels at any position. The experimental results have been introduced and discussed with respect to either engine speed up to 3500 rpm or the air index , up to 1.6. The experimental apparatus used to conduct the experiments was designed to facilitate good control on the performance parameters and ease of data collection. The levels of carbon monoxide (CO), unburned hydrocarbons (HC) and nitrogen oxides (NOx) are measured at various operating conditions.