The Different Types of Fuel, and the One That’s Right for Your Car

It wasn’t too long ago that gasoline and diesel were the only two options to power your car. But these fuel types come with serious drawbacks including high cost and environmental hazards. With the increased need to use renewable fuel sources, several other options are being used more frequently – and more are continuing to emerge. With that in mind, here are a few of the most popular types of fuel for cars, and how to determine the right one for your vehicle.

Gasoline

The most commonly used fuel for cars is gasoline. It is easily combustible, which allows for quick starting and fast acceleration. However, the high levels of carbon dioxide produced from burning gasoline is a leading contributor to pollution and, in turn, to global warming. According to the Union for Concerned Scientists, cars and trucks account for nearly one-fifth of all U.S. global-warming emissions. In response, many companies and consumers are increasing their use of alternative fuel types.

There are generally three different types or “grades” of gasoline, determined by the gasoline’s octane level. A level of 87 is considered “regular,” 91 is “premium,” and 89 is mid-grade. The grade of gasoline you should use depends on the type of vehicle and engine you have. (More on that below).

Diesel

Along with gasoline, diesel is the other popular form of fuel, used specifically for diesel engines. Diesel vehicles are more fuel efficient, often traveling about 20% to 35% farther on a gallon of fuel than their gas-powered counterparts. Therefore, vehicles that are travelling far distances, such as trucks and vans, commonly use diesel engines. It also produces less carbon dioxide than gasoline. However, it does create nitrous oxide, which causes smog.

Liquified Petroleum

Better known as propane, liquified petroleum is a much cleaner and cheaper form of fuel. Many hybrid cars in foreign countries such as the United Kingdom have been designed to use propane. However, automobiles in the United States rarely use it. The only way to use propane domestically is to convert your vehicle’s gas engine.

Ethanol

Ethanol is a popular biofuel made from sugar cane, barley, corn and other natural resources. It is most often used as an additive in other fuel sources in order to help cut down on hazardous emission. According to the U.S. Department of Energy (DOE), more than 98% of U.S. gasoline contains ethanol, typically E10 (10% ethanol, 90% gasoline). But ethanol can also be used alone. It’s one of the few alternative fuel types that can be used with a gas engine without any modification.

Ethanol is a sustainable resource, so its use should only increase in the future. However, ethanol produces less energy than gasoline, meaning cars would get a much lower mileage.

Compressed Natural Gas

Compressed natural gas is a clear, odorless and non-corrosive gas that can be used in liquid or gas form to run a combustion engine, though gas engines would need to be converted to use it. The fuel produces approximately 80% less emissions than gasoline. Additionally, vehicles that run on compressed natural gas are similar in power, acceleration, and cruising speed to gasoline or diesel vehicles. Compressed natural gas can limit driving range, though, as less overall gas can be stored in the same size gas tank.

Biodiesel

This renewable, biodegradable liquid fuel is made from vegetable oils, animal fats or recycled cooking grease. According to the DOE, biodiesel emissions are 74% lower than those from petroleum diesel. Diesel vehicles can generally use a low percentage of biodiesel without any engine modification. However, higher levels of the fuel will require modifications.

Determining the Type of Fuel for Your Car

Gasoline vs. Diesel

Most vehicles in the United States run on gasoline or diesel fuel. The driver’s manual should dictate the fuel type your car needs. There should also be a label on the fuel door that reads something along the line of “Diesel Fuel Only” or “Unleaded Gasoline Only.” If there’s ever a doubt, call the manufacturer.

It is imperative that you put the proper fuel in your car’s tank. Gas engines cannot combust diesel fuel and vice versa, so the car won’t start if it is filled with the wrong fuel type. Even worse, it can cause serious damage to the engine.

AAA Approved Auto Repair Facilities can help get your car back out on the road. Find the nearest one here.

Regular vs. Premium

As stated previously, gasoline grades are dependent on the fuel’s octane level. Higher octane levels ensure the gas burns evenly, which helps keep your engine cleaner and improve performance. Therefore, it is commonly used in vehicles with high-compression engines or turbochargers, like sports cars.

The car’s manual should state the gasoline grade needed. It may suggest premium gas but not require it. If this is the case, your car should be able to run fine with lower grade gas, and it could save you money.

Alternative fuels

While gasoline and diesel are the most common and readily available types of fuel for cars, in most cases, any vehicle can be converted to use an alternative fuel source. Engines can be modified to either operate exclusively on one alternative fuel or to have two separate tanks and fuel systems – one for conventional fuel and another for an alternative fuel. Converting your engine would cause some upfront costs but should save you money in the long run. With increasing gas prices, alternative fuels present an inexpensive option.

AAA members can save money at the pump with Shell’s Fuel Rewards program.

Motorists can find the cheapest gas prices wherever they are by using the AAA Mobile App.