Components of a Direct Injection gasoline System
Common Rail System -- A long
metal cylinder called a fuel rail distributes fuel to the injectors under extremely high pressure.
Distributor and Inline Pump System -- Either
a rotary wheel distributor or plunger-style pump is used to push pressurized
fuel to the injectors.
Unit Direct System -- In
this setup, the injector and a fuel pump just for that injector are integrated into a single unit and
positioned over each cylinder
Advantages over indirect injection:
controlled emissions levels
aggressive ignition timing curves
control over amount of fuel and injection timings
throttling losses in engines without a throttle plate
efficiency losses due to deposits on the piston surface.
deposits on the intake ports and valves.
mileage misfire codes.
the fuel travels via pump from the fuel tank, through the fuel line and into
fuel injectors that are mounted into the engine.
injectors spray gasoline into the air intake manifold, where fuel and air mix
together into a fine mist. At precisely timed intervals, intake valves open,
corresponding to the different cylinders of the engine.