The air and fuel(petrol) enters the carburetor through separate ports assigned for them.
If undisturbed, they get mixed inside the carburetor at stoichiometric ratio *We can get rich mixture by opening the choke valve.
After mixing, the air-fuel mixture enters the cylinder through inlet valve during suction stroke.
The fuel injection system consists of a fuel injector (nozzle) whose operation is controlled by electric circuits through sensors. * The Electronic Control Unit (ECU) is used for the control.
The air from the air filter enters the cylinder through inlet valve during suction stroke.
The fuel injection begins at the end of compression stroke.
The fuel is sprayed like moist.
Due to atomization, the air and fuel get mixed inside the cylinder.