KAJIAN EKSPERIMENTAL PENGARUH PENGGUNAAN BAHAN BAKAR CAMPURAN BIOETANOL-BENSIN TERHADAP KINERJA DAN EMISI GAS BUANG MOTOR BENSIN STANDAR 4 LANGKAH TIPE 4 K

Abstract

The number of gasoline engine vehicles increases rapidly from year to year. This fact resulted in the increase of exhaust gas emission, which affected environment quality and health. Therefore, it is important to do a research work on this exhaust gas reduction of the vehicles. Moreover with the decreasing crude oil stock in Indonesia, renewable fuel, such as bioethanol, may take an important role. As an alternative to solve this problem, an experimental research on mixed bioethanol-gasoline fuel of 4K type 4 stroke standards in gasoline engine was done. This research was focused on analyzing the engine performance and the exhaust gas emission. Composition of bioethenol in the mixed bioethanol-gasoline was varied from 0 to 25%. The results showed that the mixed fuel did not only improve the engine performance, but also decreased toxic exhaust gas emission. When engine was operated at 2500 rpm with 25 % bioethanol mixed fuel, it produced  best composition of exhaust gases of 1,21% CO; 12,20 % CO₂; 227 ppm HC; and 3,60% O₂. The engine performance indicators showed brake horse power (BHP) of 44,4 hp; torque (T) value of 126,6 kg-m; break specific fuel consumption (BSFC) value of 0,23 kg/hp-hour; and thermal efficiency (h_th) value of 35%. When engine was operated without the presence of bioethanol, gas emission showed worst composition of 2,20% CO, 11,70% CO₂, 277 ppm HC, and 1,07% O₂. The engine performance indicators in this test condition showed BHP value of 45,4 hp, T value of 129,5 kg-m; BSFC value of 0,255 kg/hp-hour; and h_th value of 30%.