In the past, cars were mainly designed to run on essentially pure gasoline blends. Because ethanol was not produced in large amounts, and can cause a number of problems for gasoline-based engines, it was never included in large amounts in the fuel. Because of this, older generations of cars can have decreased performance and longevity due to the growing use of ethanol in modern gasoline blends.

Maritime Motors Test Edit

In a study of marine motors, a number of different sizes and types of engines were tested using a Wide Open Throttle stress test, common for marine engines, using gasoline with no ethanol as a control being compared to a 15% ethanol gasoline mix, or E15. The engines weren’t altered in any way before the test to adjust for the increased ethanol mixture.[1]

While both engines showed signs of decreased efficiency after the 300 hour test, misfiring and partial

Engine deposits

Connecting Rod Carbon Deposit Comparison

combustion was more common on some motors. In addition, much more physical wear was seen on engines with the E15 fuel, including higher carbon deposits, signs of deterioration on elastomeric parts, and even high cycle fatigue cracks on exhaust valves for one motor. One engine test could not be completed with the E15 mix, as the engine failed after only 256 hours. In addition, one more showed emissions in excess of those allowed by the Family Emissions Limit, but did not exceed that limit when operated on E0 fuel.

Although these results were based only on marine motors, it is immediately evident that many engines are simply not prepared for the high temperature and physical characteristics of ethanol as a fuel, as they have in the past been used only with E0 fuel. In particular, lubrication and durability are points of interest when engines are running on fuel including ethanol.

Conclusion and Analysis Edit

The aforementioned test seems to suggest ethanol cannot simply be introduced as a fuel to already existing trucks and cars. However, marine engines have proven to be less resilient than those powering road vehicles, and the ethanol percentage used in the test is higher than allowed in automobiles.

Currently, gasoline is permitted to contain up to 10% ethanol. This allows gasoline companies to supplement their supply of oil with ethanol. With ethanol capacity approaching about one tenth of the total gasoline usage in the US, much of what is already being produced is able to be used in fuel already. With the small scale production that has already begun, there is much fewer problems than the future may hold.

In the future, as ethanol production grows larger and perhaps eventually even outstrips gasoline production, even allowing the small 10% of fuel to be ethanol will not be enough to fully utilize biofuels. To combat this problem, Congress has introduced the Open Fuels Standard Act of 2011, requiring that 80% of all vehicles be compatible with ethanol and methanol by the year 2018, a deadline earlier even than the 2022 deadline for increased ethanol production.

While the bill is perhaps slightly premature, it isn’t the first step that would be taken towards full integration of ethanol into the fuel supply. Already, millions of vehicles worldwide are “Flex-Fuel” vehicles, meaning that they are compatible with gasoline as well as E85 fuel; a mix comprised of 85% ethanol. Almost 10 million Flex-Fuel vehicles are already on US roadways, but each uses on average less than one gallon of Flex-Fuel a month.[2] This introduces another problem:  even in 2018, when automobiles are compatible with ethanol, consumers may choose to not use the new fuel. Until ethanol production ramps up to much higher levels, it could be difficult to break the habits of consumers and introduce the new system. However, it is clear that the main issue lies not with integration, as most automobile engines can handle ethanol-based fuels, but in the very low production levels ethanol currently holds.

References Edit

  1. Hilbert, D. (2011, June 30). High ethanol fuel endurance. Retrieved from
  2. Motavalli, J. (2012, 03 1). Flex-fuel amendment makes for strange bedfellows. . Retrieved from

Picture References Edit

Engine deposits

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