The type of cooling system used from the given figure is

There are two types of cooling systems used in the engines

Direct cooling – Air cooling

Indirect cooling – Water cooling

Air cooled Engines: In air cooled engines, cylinders are semi-independent. They are not grouped in a block. Metal fins are provided on the head and cylinder to help dissipate heat from the engine. In some engine’s fans are also used to improve air circulation around cylinder and heads. This type of cooling system is employed in two-wheelers and small stationary engines.

Water cooled Engines: Two types of water-cooling systems are used

1. Thermo-siphon system:

In this system, no pump is used for water circulation. Water circulation is obtained due to the difference in the densities of hot and cold water. Water absorbs the heat and rises up in the block and goes to the radiator’s top side. Water is cooled in the radiator and then again goes to the water jacket in the engine. This system is simple, but rate of cooling is very slow.

2. Forced circulation system (Pump Circulation system)

In this system water is circulated by a pump. The pump is driven by a belt which is connected with the crank-shaft pulley. The circulation depends upon the engine speed. More water is circulated at higher speed. This cooling system is very fast.