If you run a commercial fleet, you probably know that some vehicles run on diesel, while others use unleaded gasoline. But you may not have thought much about the difference. The names can be misleading—gasoline—aka “gas” is not a gas in the chemical definition. Both diesel and gasoline are fuels—and some gasses can be fuels, too. It’s admittedly confusing!
While both gasoline and diesel are used to fuel vehicles, they have some key differences. Here’s what you need to know.
Diesel fuel is made using a hydrocarbon mixture that is a byproduct of the distillation of crude oil. It is denser than gas. Diesel’s boiling point is higher than that of water, which means it has an extremely low evaporation point. It’s classified as combustible, meaning it requires compression and heat to function.
Gasoline is made from refined crude oil and other petroleum liquids which are blended with other ingredients and fuel ethanol into finished motor gasoline. It’s available in different grades and qualities. Regular gas can evaporate at room temperature, and is considered a flammable liquid, which means that it requires a spark. So, while diesel fuel will extinguish a lit match, a lit match will ignite the fumes of gasoline before it even reaches the liquid.
Diesel’s chemical composition contains more atoms, which help provide more power during combustion—but also produces more greenhouse gas than gasoline.
Because diesel is several times more powerful than gas, it’s the go-to fuel for industries that require that extra energy, such as trucking and construction. The power output also means it’s more efficient than gasoline. One gallon of diesel produces 147,000 BTUs compared to 125,000 BTUs of a gallon of regular gasoline.
Gasoline is a less-dense fuel. It’s better at providing speed than sheer power, which is why it’s better for automobiles. It also performs better in colder temperatures.
The key difference between the two fuels is the combustion process in the engine.
In gasoline engines, the fuel is first mixed with air and then compressed by the piston. Then a spark plug creates a spark to cause an explosion, called combustion. The explosion moves the piston, which moves the crankshaft and ultimately moves the wheel.
Diesel engines don’t need spark plugs for combustion. Instead of using a spark for ignition, diesel fuel needs to be vaporized before it goes to the combustion chamber, where it ignites at a high temperature.
As the piston compresses the air, it gets hotter due to pressure. The hot air, when mixed with vaporized diesel, ignites resulting in combustion.
We’ve been working with businesses across southern Maine for more than 30 years and we understand your commercial fueling needs. No two businesses are alike, and most need both regular gas and diesel fueling options for their fleets and equipment. We can help, from planning and scheduling on-site deliveries, to tracking your usage patterns to improve efficiency.
Contact us for more information today. We’ll be happy to help you get started.