Farm Power And Machinery (1+1)

Compression ignition engine (Diesel engine)

• In compression ignition engines only air is drawn into the cylinder instead of mixture of air and fuel as in carburetor type engine. Compression of the air during the compression stroke makes the charge very hot, and increasing pressure and temperature. At the end of the compression stroke, diesel fuel is injected into the cylinder in atomised form through an injector, which ignites in the engine cylinder, causing rise in pressure which forces the piston to move downwards.
• The basic elements of CI engine are same as that of spark ignition engine but the method of fuel introduction and ignition are different to a great extent. The engine has high compression ratio hence the air in the cylinder attains a very high temperature and pressure at the end of the compression stroke. At the end of the compression stroke, the fuel is sprayed into the cylinder through an atomizer (injectors).
• The cylinder contains air at high pressure and temperature; hence the fuel begins to burn as soon as the fuel reaches the cylinder in atomised form. Such engines are called compression ignition engines because the ignition of fuel takes place due to heat of compression. CI engine is equipped with fuel injection pump and injectors. The injectors protrude into the combustion space of the engine.