Investigation of the behaviors of higher alcohols in a spark-ignition engine as an oxygenated fuel additive in energy, exergy, economic, and environmental terms

Today, additives with high oxygen content are added to gasoline to reduce its environmental damages. Alcohols are the most important ones among them. Short-chain alcohols such as methanol and ethanol are preferred for gasoline engines; however, a limited number of studies where long-chain alcohols are used were carried out. In this study, the engine performance and exhaust emission values were determined using gasoline, PEN25 (25% 1-pentanol + 75% gasoline), HEX25 (25% 1-hexanol + 75% gasoline), and HEP25 (25% 1-heptanol + 75% gasoline) in a four-stroke spark-ignition engine (SIE) with single cylinder and water cooling under constant speed (1500 rpm) and different load conditions (4, 8, 12, and 16 kg). The energy, exergy, economical, environmental, and sustainability parameters were analyzed based on the obtained data. Finally, it was concluded that the addition of different heavy alcohols to gasoline increases fuel consumption and reduces thermal efficiency. Due to the low energy content of alcohols, the energy and exergy efficiencies of blended fuels were lower than that of gasoline. At full load, the thermal efficiencies of gasoline, PEN25, HEX25, and HEP25 were found to be 37.36%, 28.27%, 31.92%, and 34.84%, respectively; meanwhile, the exergy efficiencies were in the order of 34.83%, 26.53%, 29.96%, and 32.70%. Although the economical analyses were affected adversely since alcohol prices are higher than gasoline prices, it was found that fuel blends gave better results than gasoline in terms of environmental aspect. The net work cost values of gasoline, PEN25, HEX25, and HEP25 was calculated to be 86.76%, 84.99%, 85.64%, and 85.39%, respectively. If the production of heavy alcohols is increased, then their prices may decrease. This is one of the priority objectives for heavy alcohols being an alternative additive for gasoline.GRAPHICS]

Automated summary

The addition of high-oxygen additives, such as alcohols, to gasoline is an important method to reduce environmental damage. While short-chain alcohols like methanol and ethanol are commonly used, there have been few studies on the use of long-chain alcohols. This study examines the engine performance and exhaust emissions of various alcohol-gasoline blends, and analyzes their energy, exergy, economical, environmental, and sustainability parameters.