Why Aren't Cars Run on Alcohol Instead of Gasoline?
The idea of using alcohol as a fuel for cars seems intriguing, given its potential benefits. However, there are numerous technical and practical reasons why cars today are not powered by alcohol. This article delves into the challenges and limitations of using alcohol as a primary fuel for vehicles, particularly focusing on its impact on mileage, engine design, and environmental concerns.Technical Challenges in Alcohol Fuel Usage
The transition from gasoline to alcohol as a fuel source requires significant adjustments in both the engine and the overall vehicle system. As one individual noted, the carburetor must be specially adjusted to achieve the correct fuel/air mix, and in some cases, the computer controlling the engine (e.g., in fuel injection systems) needs reprogramming. These modifications are not trivial and can be complex.For example, one user successfully ran a car on alcohol, but noticed that one gallon of alcohol lasted for an entire year, compared to just a few months with gasoline. Such changes extend to engine design, where a higher octane rating (up to 118) is beneficial, but gasoline's lower octane can cause issues.
Impact on Mileage and Practicality
One of the main reasons against using alcohol as a primary fuel is the impact on mileage. Research indicates that while alcohol might have a higher octane rating, it significantly reduces fuel efficiency. A vehicle that gets 30 miles per gallon (MPG) with gasoline can see that drop to around 15 MPG with alcohol. This dramatic decline in fuel efficiency poses a significant challenge for daily use.Additionally, there are logistical hurdles in producing alcohol and its potential environmental drawbacks. For instance, to produce a gallon of alcohol, more than a gallon of diesel fuel might be required for the corn fermentation process, making the overall environmental benefit questionable. This practical issue must be considered, especially when discussing sustainability and reducing carbon footprints.
Engine Design and Adaptations
While it is possible to adapt engines to run on alcohol, it involves making substantial changes to the fuel delivery system and engine components. Alcohol reacts differently with the air-fuel mixture, and it can pick up water from the air, leading to several complications. For instance, it absorbs water and holds it in suspension, which can cause various issues. The filters and injectors can plug up quickly, and the alcohol itself can be corrosive to metal components, requiring different types of engine rubbers and seals.Historical Perspective and Practical Use
In 1981, during a visit to Brazil, it was observed that many cars there ran on ethanol, a form of alcohol. However, the experience back then did not reflect the broader practical considerations of urban and regional driving. Currently, while ethanol is still used in some countries, it has not become a primary fuel source for the majority of vehicles due to the reasons mentioned above.It's worth noting that alcohol can be used in dragster engines, particularly when combined with nitrous oxide and forced induction systems. These applications are specialized and not suitable for street cars, owing to the significant drop in mileage and the increased complexity and maintenance required.