Using Alcohol as Fuel | Advantages, Disadvantages [Comparison with Gasoline]

By | June 28, 2018

Alcohol as Fuel

Have seen movies in which crazy scientist uses alcohol as a fuel to his car.

That is not merely a science fiction.

Anybody can use alcohol as a fuel.

Alcohols which are most promising as a fuel are Methanol and Ethanol.

But here are some advantages and disadvantages associated with this fuel.

Advantages of using alcohol as a fuel

  1. It can be obtained from both natural and manufacturing methods.
  2. It has a very high octane number (above 100) and a very good flame speed.
  3. It produces less emissions than gasoline (petrol).
  4. Due to cooler intake, volumetric efficiency of engine running on alcohol is good. 
  5. Alcohol has low sulphur content in fuel.
  6. More moles of exhaust gases produced provide more power to expansion stroke.

Disadvantages of using alcohol as a fuel

  1. Calorific value of alcohols are almost half to that of gasoline. That means you need almost double amount of alcohol to travel same distance as on using gasoline.
  2. Combustion of alcohols produce aldehydes. If alcohol as a fuel is used in same amount as gasoline today, then aldehydes emission will be a serious problem.
  3. Alcohol is corrosive in nature. Hence, design consideration are there when using it as a fuel.
  4. It is difficult to start the engine when the temperature of the engine is below 10 °C while using alcohol.
  5. Alcohol has poor ignition characteristics.
  6. Alcohols produce almost invisible flames while burning, it may cause serious safety problems.
  7. Due to low vapour pressure the air can flow into alcohol storage tank and can form a combustible mixture there. Which may cause explosion.
  8. Many people find odor of alcohol offensive. It may cause headaches and dizziness.
  9. There is possibility of vapour lock in fuel delivery systems.

Comparison between Gasoline and alcohol as a fuel

Property Gasoline Alcohol
Sources Natural Both natural and man made
Octane Number Comparatively low High
Overall emissions High Low
Volumetric efficiency Low High
Sulphur Content High Low
Calorific value High Low
Corrosive in nature Low High
Cold weather starting Good Poor
Ignition Characteristics Good Poor


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