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
- It can be obtained from both natural and manufacturing methods.
- It has a very high octane number (above 100) and a very good flame speed.
- It produces less emissions than gasoline (petrol).
- Due to cooler intake, volumetric efficiency of engine running on alcohol is good.
- Alcohol has low sulphur content in fuel.
- More moles of exhaust gases produced provide more power to expansion stroke.
Disadvantages of using alcohol as a fuel
- 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.
- 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.
- Alcohol is corrosive in nature. Hence, design consideration are there when using it as a fuel.
- It is difficult to start the engine when the temperature of the engine is below 10 °C while using alcohol.
- Alcohol has poor ignition characteristics.
- Alcohols produce almost invisible flames while burning, it may cause serious safety problems.
- Due to low vapour pressure the air can flow into alcohol storage tank and can form a combustible mixture there. Which may cause explosion.
- Many people find odor of alcohol offensive. It may cause headaches and dizziness.
- There is possibility of vapour lock in fuel delivery systems.
Comparison between Gasoline and alcohol as a fuel
|Sources||Natural||Both natural and man made|
|Octane Number||Comparatively low||High|
|Corrosive in nature||Low||High|
|Cold weather starting||Good||Poor|