Effects of intake air temperature on energy, exergy and sustainability analyses in an RCCI engine fueled with iso-propanol and n-heptane

Abstract

In this study, performance and emission tests were carried out in a diesel engine operating with RCCI combustion mode by varying the amount of fuel taken into the cylinder and the air temperature in one cycle. Thermodynamic performance was determined by making energy, exergy and sustainability analyzes using the data obtained in the tests. The effects of change in intake air temperature on thermal efficiency, exergy efficiency, exhaust exergy, exergy destruction, and sustainability index were calculated. As the temperature of the air taken into the cylinder increases, the lost exergy decreases and the exergy efficiency increases. At 2500 rpm engine speed, when the amount of fuel taken into the cylinder is 20 mg/cycle, if the inlet temperature is 30°C, 50°C and 70°C, the exergy destruction is 9.873 kW, 9.760 kW and 9.394 kW, respectively. The highest thermal and exergy efficiencies were calculated as 31.58 % and 28.7 %, respectively, at an engine speed of 2000 rpm, when the fuel taken into the cylinder per cycle was 20 mg and the intake air temperature was 70°C. Moreover, the sustainability index was found to be 1.4 under the same conditions. The thermodynamic results show that RCCI mode can be used as alternative combustion mode.