Fuel Delivery and Air Induction: Description and Operation

Fuel System:

PURPOSE
The multi-point fuel injection system (Digifant I controlled), delivers a precise quantity of fuel to each cylinder under all engine speed and load conditions.

COMPONENTS
^ Fuel tank
^ Electric fuel pump
^ Fuel delivery and return lines
^ Fuel filter
^ Pressure regulator
^ Electric injection valve
^ Air filter
^ Induction system
^ Digifant I control module

OPERATION
The electric roller-cell pump supplies high volume fuel from the tank to each fuel injector. A large volume injector rail ensures equal distribution to each valve. The injector rail is fitted with a pressure regulator which maintains a constant pressure differential (fuel pressure and manifold pressure) at the injection nozzles. Excess fuel is directed back to the fuel tank. Because of the constant flow, cool fuel prevents formation of vapor bubbles and ensures good hot starting.

Since fuel pressure is held constant, fuel injection quantity is dependent upon the frequency and duration of the injection pulses. Digifant I constantly calculates the amount of fuel needed and adjusts injector signals via output stages within the ECU.


CONSTRUCTION
The fuel tank is located underneath the vehicle behind the front suspension. The tank is made of plastic. The capacity of the tank is 21.1 gallons (80.0 litre).

The fuel pump is located inside the fuel tank. Fuel is pumped from the tank through the fuel filter to the fuel rail, cold start valve and the injectors.

The fuel pressure is regulated by a vacuum- control led fuel pressure regulator. The regulator is located at the end of the fuel rail in the fuel return outlet. It maintains the fuel pressure at 36 - 43 psi (2.5 - 3.0 bar).