While "ASTM E85" isn't a specific ASTM standard itself, the term commonly refers to E85 fuel, a specialized blend of ethanol and gasoline that is defined by its composition and required to comply with ASTM Standard D5798-11. This standard ensures the quality and consistency of E85, making it suitable for its intended use in alternative fuel vehicles.
Understanding E85 Fuel
E85 is a blend of ethanol (a renewable alcohol fuel) and gasoline. Its name, "E85," signifies that the fuel contains no more than 85% ethanol by volume, with the remainder being gasoline. This specific formulation is designed for use in vehicles equipped to handle higher concentrations of ethanol.
Key characteristics of E85 include:
- Composition: Primarily ethanol (typically 51-83% by volume, but can be up to 85%) blended with gasoline.
- Renewable Component: Ethanol is often derived from agricultural products like corn, making E85 a more renewable fuel source compared to pure gasoline.
- Higher Octane: Ethanol typically has a higher octane rating than gasoline, which can offer performance benefits in engines designed to utilize it.
- Cleaner Burning: E85 can result in lower emissions of certain pollutants compared to conventional gasoline, contributing to improved air quality.
The Role of ASTM Standard D5798-11
The American Society for Testing and Materials (ASTM) develops and publishes technical standards for a wide range of materials, products, systems, and services. For E85 fuel, ASTM Standard D5798-11, "Standard Specification for Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-Ignition Engines," is the critical compliance benchmark.
This standard sets forth the necessary chemical and physical properties that E85 must meet to ensure safe and efficient operation in compatible vehicles. Without such a standard, fuel quality could vary significantly, potentially leading to engine damage or poor performance.
Key Aspects of E85 Compliance via ASTM D5798-11:
| Aspect | Description |
|---|---|
| Composition | Specifies the permissible range of ethanol content (e.g., 51-83% by volume) and the type of gasoline blendstock. |
| Vapor Pressure | Regulates the fuel's tendency to evaporate, crucial for engine starting and preventing vapor lock, especially across different seasons and climates. |
| Corrosion | Sets limits on corrosive properties to protect fuel system components, as ethanol can be more corrosive than gasoline. |
| Contaminants | Defines maximum levels for impurities such as water, sulfur, and inorganic substances to prevent engine and fuel system damage. |
| Appearance | Ensures the fuel is clear and bright, indicating absence of suspended particulate matter or excessive water. |
| Denaturant | Specifies the type and amount of denaturant (usually gasoline) to make the ethanol undrinkable and exempt from beverage alcohol taxes. |
| Labeling | Mandates proper labeling for E85 dispensers, informing consumers about the fuel type and its suitability for flexible-fuel vehicles. |
The rigorous specifications outlined in ASTM D5798-11 are vital for maintaining the integrity and reliability of E85 fuel. You can learn more about ASTM International and their standards at www.astm.org.
E85 and Flexible Fuel Vehicles (FFVs)
E85 is exclusively designed for Flexible Fuel Vehicles (FFVs). These vehicles are specially manufactured with modified fuel systems and engine components that can safely and efficiently operate on a wide range of fuel mixtures, from 100% gasoline to E85. Using E85 in a non-FFV can lead to significant damage to the fuel system and engine.
Practical Insights & Considerations
- Availability: E85 fueling stations are less common than gasoline stations, though their numbers are growing, particularly in regions with strong agricultural ethanol production.
- Fuel Economy: Due to ethanol's lower energy content per gallon compared to gasoline, FFVs typically experience a reduction in miles per gallon when running on E85.
- Environmental Impact: While E85 can offer lower greenhouse gas emissions depending on the ethanol production methods, its overall environmental benefits are subject to ongoing debate and lifecycle analyses.
Understanding E85 and its adherence to ASTM standards ensures that this alternative fuel option remains a viable and safe choice for compatible vehicles.
