CLASSIFICATION OF ENGINES AS PER FUEL USED

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(a) Heavy Oil Engine.

It can burn fuels of high viscosities, e.g. 1500 sec. Redwood No. 1 or 350 sec. Redwood No. 1.

(b) Diesel Oil Engine.

This uses diesel oil.

(c) Gasoline Engine.

This uses gasoline as fuel. It can also use ‘kerosene’. As the 'perfect mixture' of fuel and air is led to cylinder for compression, compression ratio is limited to 7 to avoid self- ignition, power loss, knocking, etc.

(d) Gas Burning Engine.

It uses gaseous fuels at higher compression. Three ways have been adopted to burn gas at higher compression. The engines are named accordingly as follows:

i) Gas Diesel Engines

They compress air alone. At the end of compression, they inject the gas at high pressure into the cylinder just at the moment it is to fire. With gas, a small amount of ‘pilot oil’ is also admitted to assist the ignition and to cause smooth and prompt ignition.

ii) Dual Fuel Engine

Admit the gas and air at the same time and compress the gas/air mixture at diesel compression ratio. At the end of compression, they inject fuel oil, which the high temperature of the gas-air mixture ignites to fire the mixture. Using ‘lean mixture’ unlike to ‘perfect mixture’ of gasoline engine prevents self-ignition.

iii) High Compression, Spark Ignited Gas Engines.

Like dual fuel engines, they compress a mixture of gas and air to high pressure, preventing self-ignition by using a ‘lean mixture’ but they use spark, instead of oil, for ignition.