ITS Chemistry Expert Prof Dr Hendro Juwono MSi, while showing biofuel research samples from plastic waste

ITS Campus, ITS News — The practice of blending gasoline, which is currently in the spotlight, invites many questions from the public about the quality of the fuel and its effect on vehicle engine performance. One crucial indicator often heard but rarely understood is the Research Octane Number (RON).

One of the Chemistry Department professors at Institut Teknologi Sepuluh Nopember (ITS), Prof Dr Hendro Juwono MSi, explained that RON, or octane number, measures fuel resistance to engine knock. Less resistant fuel will experience knocking when fuel burns prematurely due to high pressure in the combustion chamber.

Furthermore, Hendro explained that fuel generally contains octane compounds (C8) but not pure C8. The various hydrocarbon components that makeup fuel, ranging from C7 to C9, can affect RON. Also, the varying carbon chain structure, straight chain or n-octane or branched or iso-octane, contributes to the RON level. “The more branched compounds such as iso-octane, the higher the RON of the gasoline,” he said.

This principle is crucial in the fuel blending process. This 212th ITS professor explained that the final RON of a fuel depends on the composition of the hydrocarbons mixed or blended. Blending is done by combining light fractions, such as C8, which is used for gasoline, with other fractions, such as C7 or C9.

Hendro said that gasoline blending or fuel mixing is scientifically possible and legitimate. He noted that blending certain RONs can be done to achieve the desired octane value as long as the process follows proper chemical principles and meets the standards. “If the mixture is excessive or careless, the impact is not immediately visible, but engine performance will decrease in the long run,” he said.

Several ways exist to achieve a specific RON value, including adding additives. According to this man, born on June 6, 1961, additives can increase gasoline’s resistance to engine knock so that combustion can take place more stably. Some common additives used include methyl tertiary butyl ether (MTBE) and toluene.

Prof Dr Hendro Juwono MSi shows an example of fuel from his research at the Instrumentation and Analytical Science Laboratory, ITS Department of Chemistry

Regarding numbers, RON can reach a specific value through adding additives or the blending process. However, it should be understood that the same RON number does not always reflect combustion quality. The final performance of the fuel still depends on its constituent components, such as the type of hydrocarbons and chemical structure. “Even though gasoline has a high RON, an unbalanced mixture can cause inefficient combustion and damage the engine,” he said.

Not only that, Hendro also highlighted the importance of the public understanding that fuel selection, including RON numbers, should be tailored to the vehicle’s needs. Each engine has a different compression ratio, so it does not always require high-RON gasoline. “If a high-compression engine is given a low RON, it can damage the engine, and vice versa,” he explained.

In this case, Hendro expressed his hope that the public can improve their understanding of gasoline blending and RON to avoid confusion. With good literacy, people can choose a fuel that suits the engine’s needs so that vehicle performance remains optimal and energy use becomes more efficient. This is also to the goals of Sustainable Development Goals (SDGs) 7 on clean and affordable energy. (ITS Public Relations)

Reporter: Aulia Okta Wijaya
Translator: Lael Soebakir