Effect of speed and load on exergy recovery in a water-cooled two stroke gasoline-ethanol engine for bsfcreduction purposes

The most important part of the second law of thermodynamics is described asdetermining the value and source of wasted exergy in processes, and suggests concepts forreducing those losses in order to enhance eciency. so, the main purpose of this paper is tostudy the eect of alcoholic additives, load and engine speed on combustion irreversibilitiesand second law eciency. the mentioned alcoholic fuel is ethanol, which is combinedwith gasoline in dierent percentages of 5, 10 and 15%. the experiments have been donefor 2500, 3000, 3500 and 4500 rpm, and 25%, 50% and 75% full load. the results showthat, mostly, when alcoholic fuel is used, the combustion internal irreversibility increasesand second law eciency decreases, which is due to the increase in temperature dierencebetween burned combustion products and unburned mixtures, but, an increase in load andengine speeds increases second law eciency. another important outcome of the presentstudy is in demonstrating brake specic fuel consumption (bsfc) reduction, due to usingrecovered exergy from water, whose average value is 14.1%.