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 as determining the value and source of wasted exergy in processes, and suggests concepts for reducing those losses in order to enhance eciency. So, the main purpose of this paper is to study the eect of alcoholic additives, load and engine speed on combustion irreversibilities and second law eciency. The mentioned alcoholic fuel is ethanol, which is combined with gasoline in dierent percentages of 5, 10 and 15%. The experiments have been done for 2500, 3000, 3500 and 4500 rpm, and 25%, 50% and 75% full load. The results show that, mostly, when alcoholic fuel is used, the combustion internal irreversibility increases and second law eciency decreases, which is due to the increase in temperature dierence between burned combustion products and unburned mixtures, but, an increase in load and engine speeds increases second law eciency. Another important outcome of the present study is in demonstrating brake specic fuel consumption (bsfc) reduction, due to using recovered exergy from water, whose average value is 14.1%.