Fuels

FUELS

1. PERFORMANCE REQUIREMENTS OF I.C. ENGINE FUELS

In I.C. engines, heat energy is released by burning the fuel in the cylinder. The chemical reactions which permit the release of heat energy are very fast. But, the time taken in preparing a proper mixture of air and fuel depends upon the nature of the fuel and the method of introducing it into the combustion chamber. Thus, certain performance requirements are required for the fuels used in I.C. engines. .

• The combustion process in the cylinder must take as little time as possible. Also, a maximum amount of heat energy must be released during this period.

• Longer operations result in formation of deposits and side effects such as wear, etc.

• Deposits will cause corrosion of cylinder, piston and piston rings.

• Products of combustion should not be harmful when exhausted to the atmosphere.

2. PETROLEUM OIL

Fuels used in the I.C. en gines are mixtures of hydrocarbons made by refining Petroleum Oil. Products of refining of petroleum oil are:

1. Natural Gas. It is found dissolved in petroleum under the earth surface.

 2. Liquefied Petroleum Gas (LPG): Propane and butane and some other light hydro-carbons after separation from natural gas, if stored under pressure, form liquid. This is called Liquefied Petroleum Gas (LPG). It is supplied in containers under pressure.

3. Gasoline (Petrol): It is the lightest liquid petroleum. Boiling point is around 200°C.

 4. Kerosene: Kerosene is heavier than gasoline. Its boiling range is 150°C to 300°C.

5. Diesel Oil: Diesel Oil is a fuel which lies between kerosene and lubricating oils. Boiling range is 200°C to 370°C. This forms the fuel for C.I. engines.

6. Lubricating Oils: Lubricating oils are made up of heavy distillate of petroleum oil.

3. LPG AS SI ENGINE FUEL

There is an increasing trend to use LPG as a motor fuel. LPG consists of hydrocarbons of such volatility that they exist as gases under atmospheric conditions.

Advantages of LPG

• It mixes easily with air. Therefore it gives better manifold distribution.

• It burns cleanly. Therefore, residue and oil contamination are minimum.

• It is cheaper than petrol.

 Disadvantages of LPG

. • Its characteristic odour is faint. Therefore, leakage cannot be easily detected.

 • Handling has to be done under a pressure of about 18 kgf/ sq.cm.