Gatot Setyono, Moh Khusaini, Nashi Widodo, Slamet Wahyudi
This research investigates the viability of tamanu oil (Calophyllum inophyllum), a renewable and non-edible vegetable oil, as an oxygenated fuel additive in multi-component fuel blends for spark-ignition (SI) engines. The primary objective of this research is to evaluate how such blends can be utilized to enhance combustion performance and minimize pollutant emissions while maintain-ing compatibility with existing engine architecture and without requiring changes to the engine hardware. To solve this problem, five fuel blends (PBBT-1 to PBBT-5) were created by varying the ratio of tamanu oil from 2% to 10% along with the addition of 5% n-bu-tanol and 5% 2-butoxyethanol, using Pertasol as the base fuel. Engine tests were conducted at a constant compression ratio of 11:1, over a range of engine speeds from 4000 to 9000 rpm. Of the tested blends, PBBT-5 exhibited the maximum improvements, with a 42.94% enhancement in thermal efficiency and 34.13% reduction in specific fuel consumption and CO (24.26%), HC (20.27%), and NOx (29.04%) emissions reduction. These enhancements are attributed to the synergism between the oxygenated additives and tamanu oil’s slow-combustion and lubricating characteristics, enhancing more complete combustion and improved f lame propaga-tion. The novel approach adopted in this research is distinguished by the use of sustainable feedstocks, improved combustion quality and efficiency, and the potential for easy integration into current engine designs, thus solving the performance-emission paradox. This research establishes the feasibility of tamanu oil blends as a sustainable and eco-friendly alternative to conventional transpor-tation technologies under normal operating conditions. © The Author(s) 2026.
Department of Economics, Department of Biology, Department of Mechanical Engineering, Brawijaya University, 10-11 Veteran str., Ketawanggede, Lowokwaru Sub-District, East Java, Malang, 65145, Indonesia
