Fuel Delivery and Air Induction: Description and Operation

FUEL SUPPLY
Fuel is drawn from the fuel tank via an electric pump. It then is sent through the fuel filter, to the fuel rail at a constant pressure. A fuel pressure regulator, mounted on the fuel rail, maintains correct operating pressure and allows excess fuel to return to the fuel tank.

AIR INDUCTION SYSTEMS
The intake system is divided by two resonance flaps which permits optimization of oscillation in the intake manifold over a large speed range, referred to as "resonance charging".

Resonance flaps are activated by the DME control unit via a vacuum solenoid. The solenoid operates a diaphragm valve which opens the resonance flaps after reaching an engine speed of 5500 rpm. The solenoid and diaphragm valve close when engine speed drops below 5400 rpm, the flaps being spring-loaded to close.

To avoid seizure of the flaps due to carbon deposits in the intake, the solenoid is activated briefly each time the ignition is turned on. This opens and closes the flaps.