Biofuel E5, E10: Essential Usage Guidelines

Meanwhile, E5 RON 92 gasoline will continue to be permitted for use alongside E10 until the end of December 2030. This regulation has left many car and motorcycle owners, especially those with older vehicles, concerned about compatibility and the impact of these biofuels on their engines.

Differences Between E5, E10, and Traditional Gasoline

E5 and E10 are biofuels, produced by blending traditional mineral gasoline with bioethanol. E5 contains 5% ethanol and 95% mineral gasoline, while E10 has a higher ethanol content at 10%, with the remainder being mineral gasoline.

The ethanol used in biofuels is derived from the fermentation of agricultural materials such as starch, molasses, and agricultural by-products. In Vietnam, the primary raw material currently used is dried cassava chips.

Compared to regular unleaded gasoline, ethanol is considered a “carbon-neutral” fuel to some extent. During their growth, plants absorb a significant amount of CO₂, which helps offset a portion of the greenhouse gases emitted during fuel production and combustion.

Impact of Biofuels on Engines

One notable advantage of ethanol is its very high octane rating, ranging from 108 to 109 RON. When blended with gasoline, ethanol increases the fuel’s octane rating, enhancing its knock resistance in engines.

Additionally, ethanol has a higher oxygen content than mineral gasoline, enabling more complete combustion in the engine’s cylinders. This not only reduces harmful emissions like CO and HC but also ensures smoother and more efficient engine operation under certain conditions.

For E5 and E10 gasoline, users do not need to make technical adjustments when switching from traditional gasoline to biofuels, provided their engines are compatible. However, using fuels with ethanol content exceeding 10% increases the risk of damage to metal components, rubber seals, plastics, and polymers in the fuel system.

Are E5 and E10 Compatible with Older Cars and Motorcycles?

According to technical experts, most cars and motorcycles manufactured from around 2011 onward are designed to be compatible with E5 and E10 biofuels. These vehicles can use biofuels without any modifications.

However, for older vehicles, especially those with carburetors, users should carefully check the manufacturer’s recommendations. Information about suitable fuel types is typically found in the user manual, on a label inside the fuel tank cap, or can be confirmed directly with the vehicle manufacturer.

If an engine not designed for biofuels is used with E5 or E10, ethanol’s hygroscopic and corrosive properties can damage the fuel injection system, rubber seals, fuel lines, and combustion chamber. Conversely, vehicles designed for biofuels use corrosion-resistant materials and fuel systems, ensuring long-term safe operation.

Important Considerations When Using E5 and E10

Even for compatible vehicles, users must be aware of biofuels’ hygroscopic nature. If a vehicle is unused for extended periods (3–4 weeks or more), ethanol can absorb moisture from the air, causing separation between gasoline and water-laden ethanol. The heavier water settles at the bottom of the tank, potentially causing rust and damaging the fuel pump when the vehicle is restarted.

While the theoretical shelf life of E5 and E10 is around three months, users cannot accurately determine the fuel’s production date. Therefore, experts recommend draining the fuel tank or using fuel stabilizers if a vehicle is stored for long periods to minimize risks.

Furthermore, using biofuels requires more frequent maintenance, particularly replacing fuel filters earlier than when using traditional A92 or A95 gasoline, to ensure stable fuel system operation.

TH (Tuoitrethudo)

Illustrative Image: Internet