Understanding the Functionality of Flex-Fuel Vehicles

The United States is actively striving to cut down its reliance on fossil fuels, half of which are imported, leading to an unwanted dependence. Additionally, these fuels contribute significantly to pollution. This is why American car manufacturers and fuel providers are persistently innovating to create alternative fuels and vehicles compatible with them. Currently, the leading alternative fuel is E85, a combination of 15% unleaded gasoline and up to 85% ethanol. Vehicles designed to run on this blend are known as flexible fuel vehicles, flex-fuels, or FFVs [sources: Goodspeed, FlexFuel US].

Flex-fuel vehicles have been manufactured since the 1980s and are available in numerous models. The U.S. Energy Information Administration reports that over 8 million FFVs are currently on American roads. However, many drivers are unaware they own an FFV. A simple way to identify one is by checking the gas cap; since 2008, most automakers have used yellow caps for flex-fuel models. Additionally, look for labels on the fuel door, badges on the car body, or consult the owner's manual [sources: Alternative Fuels Data Center, Fuel Economy].

While FFVs are gaining popularity, they aren't a perfect solution. They do, however, help reduce fossil fuel consumption for both individuals and nations, as ethanol derived from plants is a renewable resource. Ethanol burns cleaner, benefiting both the environment and public health. On the downside, flex-fuel vehicles have lower fuel efficiency compared to traditional gasoline vehicles, can be more expensive, and E85 is not widely available at gas stations [source: Wiesenfelder].

The Mechanics Behind Flex-Fuel Vehicles

Externally, a flex-fuel car is indistinguishable from a conventional car, which is why many owners are unaware they drive one. The key differences lie in the engine and fuel system. Before delving into these, let's briefly examine the fuels that power flex-fuel vehicles.

Flex-fuel vehicles can operate on regular gasoline, various ethanol blends, and other fuel types [source: Bionomic Fuels]. Ethanol is created by fermenting plant sugars, primarily from corn in the United States, though sugar cane and other starchy crops can also be used [source: Environmental Protection Agency]. The most common ethanol blends are E85 and E95, named for their compositions: E85 contains 15% unleaded gasoline and up to 85% ethanol, while E95, often used in diesel engines, consists of up to 95% ethanol [sources: Bionomic Fuels, Clean Air Trust].

Returning to the mechanics, the internal combustion engine in a flex-fuel vehicle is engineered to utilize multiple fuel types, typically gasoline combined with ethanol or methanol, all stored in a single tank [source: Chapman]. When the vehicle is in motion, a sensor in the fuel line detects the fuel blend's alcohol concentration and relays this information to an electronic control module. This module then fine-tunes the fuel trim, or the engine's fuel delivery system, to accommodate the varying fuel mixtures [sources: Heisner, FlexFuel US].

The fueling system components in flex-fuel vehicles are specifically designed to withstand ethanol. Without this compatibility, ethanol's elevated water content could lead to internal rust and damage the fuel system over time [source: Change2E85].

Even with these specialized parts, the maintenance expenses for FFVs are typically on par with conventional vehicles, and in some cases, they may be lower due to the cleaner combustion of flex-fuels [source: FlexFuel US].

It's still uncertain whether flex-fuel vehicles will become the standard in the future. However, the exploration of alternative fuels and vehicles is a step in the right direction.