Fuel Injector: Description and Operation

Fig. 19 Injector:

CIS injectors open at a pre-set pressure and continually spray atomized fuel into the intake ports near each intake valve. The injectors are a push-fit into plastic holders in the cylinder head, and the rubber seal ring also acts as a retainer.
A vibrator pin inside the injector helps to break up and atomize the fuel droplets, Fig. 19. Each injector also has its own fuel filter to catch any particles which might enter the system after the main filter. The pin and spring seal at about 3 bar (44 psi) of residual pressure in the line between the injector and the fuel distributor to help ensure quick starting.