What Is Diesel Fuel Volatility?

by Lexa W. Lee

Volatility refers to how easily a fuel vaporizes. It affects how easily you can start your car, warm it up, and how well it runs. Diesel fuel comes in two basic grades, each with a different volatility. Automobiles use one and large trucks do better on the other.


Automobiles run better on 1-D, or number 1 diesel. Its greater volatility makes it more responsive and suitable for smaller vehicles, which are subject to more variability in speed and load.


Trucks use number 2 diesel, whose lower volatility makes for harder starts in cold weather, but better suits larger engines that are subject to higher loads and steadier speeds.


Lower-volatility fuel is more stable. The lower volatility of diesel compared to gasoline makes it a safer and more stable fuel to handle.

Flash Point

Flash point refers to the lowest temperature at which a fuel will vaporize and ignite. Flash point and volatility vary inversely. The lower the flash point, the higher the volatility. Gasoline has a higher volatility than diesel.

Effects of Lower Volatility

The lower volatility of diesel compared to gasoline results in emissions lower in carbon monoxide and hydrocarbons, although cold weather makes diesel engines more difficult to start.

About the Author

Lexa W. Lee is a New Orleans-based writer with more than 20 years of experience. She has contributed to "Central Nervous System News" and the "Journal of Naturopathic Medicine," as well as several online publications. Lee holds a Bachelor of Science in biology from Reed College, a naturopathic medical degree from the National College of Naturopathic Medicine and served as a postdoctoral researcher in immunology.

More Articles

Photo Credits

  • Thinkstock Images/Comstock/Getty Images