Compatibility of methanol fuel blends with gasoline vehicles and engines in Indonesia
(Versi bahasa Indonesia di sini.)
Indonesia is considering blending alcohols with gasoline, and it is to be used in all major gasoline products. The proposed blend, A20, would be 80% gasoline, 15% by volume methanol, and 5% by volume ethanol. Blending alcohols like methanol and ethanol into gasoline can improve fuel quality, but at the same time, utilizing mid-level gasoline-alcohol blends such as A20 in unmodified fueling infrastructure and vehicles could lead to poorer driving performance and material compatibility issues, especially in older vehicles and small engines.
This paper surveys the literature to understand both the advantages of and risks associated with using mid-level methanol-gasoline blends in unmodified light-duty vehicles, two- and three-wheelers, and small engines such as those found in lawn and construction equipment. Potential advantages of A20 over pure gasoline include increased power and torque during closed-loop operation and resistance against knocking. Potential problems include increased risk of phase separation, vapor lock, and corrosion and deterioration of metals, alloys, and polymers in vehicles and fueling infrastructure. Indonesia’s specific challenges in introducing A20 include the high sulfur and aromatic content of its base gasoline and the elevated risk of water contamination and vapor lock because of its hot and humid climate. If realized, the risks might result in decreased vehicle drivability, vehicle stalling, or damage to the engine-fuel system and fueling infrastructure. There is evidence from other countries that potential problems with mid-level gasoline-alcohol blends can be mitigated, but for Indonesia, the capital and maintenance costs are likely to be substantial.