Comparative assessment of lube oil, emission and performance of SI engine fueled with two different grades octane numbers
Muhammad Usman, Ahmad Naveed, Syed Saqib, Jafar Hussain, Muhammad Kashif Tariq
Abstract
Energy extraction from fossil fuels is a crucial requirement for the development of any country. Variation in physio-chemical properties of fuels is one of the continuous research areas related to internal combustion engines. Many studies have been performed to ascertain the effect of different gasoline octane numbers on engine performance and emissions without considering lube oil degradation. This study places emphases on the effect of 97-octane (G97) and 92-octane (G92) gasoline on lube oil degradation along with emissions and performance in a spark ignition engine. The test engine was run at 80% of wide-open throttle condition to note performance measures like brake power (BP), brake specific fuel consumption (BSFC), and emissions. Subsequently, lube oil samples were collected after engine ran for 120 hours. G92 revealed improved engine performance in terms of BP (3.1%) and BSFC (6.3%) as compared to G97. On average, gasoline with higher octane number produced 18.4% higher HC contents than G92. In addition, lube oil properties and additives diminution (Calcium) depicted a substantial deterioration for G97. The analyses of lube oil demonstrated 5.8%, 1.1% and 3.6% reduction in average flash point, viscosity and TBN for G97, respectively. However, wear analysis revealed slightly higher degradation for G92.