Gasoline Versus Diesel: What’s the Big Difference?

If you are a regular gas-user and have been most of your life, you probably just recognize diesel as that last gas pump you never use. In fact, most drivers never own a diesel car, even though you can buy everything from a truck to a BMW sedan that requires diesel fuel rather than standard gasoline. If you don’t drive a vehicle that requires diesel, chances are you’ve never really given much thought to what the difference is, besides to know well enough not to try it in your car. Is the difference really that substantial?

You can’t switch them out

At their core, diesel fuel and gasoline are different chemically. Without getting into all of the technical jargon, that means that the way that it is ignited is slightly different. In a gasoline-burning engine, an air-fuel mixture engine the chamber is compressed, and then is ignited by spark plugs. This isn’t exactly how diesel engines work.

Diesel engines don’t have spark plugs because they don’t use an external spark. Instead, diesel engines compress the air-fuel mixture so densely that it produces heat. This process is called compression ignition, and though you could do this is a standard gasoline engine, it would damage the engine.

A woman refueling a car on Circle K petrol station in Krakow, Poland | Jakub Porzycki/NurPhoto, Getty Images

Which one is better?

No gas is really better than any other, even standard gasoline with lower octane levels than others. Whatever your car is designed to have is what is best for your individual car, but that doesn’t really do much to explain the difference. In way of energy, different octane ratings don’t make a difference, and it isn’t more efficient to put higher octane gasoline in your car than it requires.

Diesel, on the other hand, is a different type of fuel and compared to standard gasoline it offers more energy per gallon.

a diesel fuel cap
Tank cap on a forklift with the inscription Diesel | Florian Gaertner/Photothek, Getty Images

Diesel fuel isn’t that dirty

Many consumers frown upon owning diesel vehicles because we have been taught to think that diesel full has higher emissions. While that might be true for certain vehicles that use it, diesel fuel technology has changed a lot in the past few decades, making it a decent option. However, with the rise of hybrids and electric cars, any type of fuel-burning vehicle is now, by default, worse for the environment

Old Petrol Pumps | Marka/Universal Images Group, Getty Images

Gas-Turbine Concept Cars That We Thought Would Take Over The Future

Depending on what octane of gasoline you buy, the price difference between diesel fuel and standard gasoline probably isn’t that great. Diesel engines do have less components, making them simpler to work on with less parks to break and repair, but regardless, most cars in the US still require gasoline rather than diesel.