Direct injection

Direct injection:-
With direct injection, the fuel is injected directly into the
combustion chamber which is usually formed by a cavity in
the piston crown.
This cavity is carefully shaped to promote air swirl and the
direction of the injector nozzle ensures that rapid mixing of
the fuel and air assists complete combustion.
Advantages - It is claimed that direct injection gives higher
thermal efficiency with lower fuel consumption. This is
bought about by the fact that no heat is lost or power wasted
in pumping air through a restricted opening into the separate
chamber or in discharging the gases from the chamber. This
gives easier starting and generally this type of engine does
not require a starting aid device, such as glow plugs.
Disadvantages - This kind of injection is prone to “diesel
knock”.