Multec 3.5 Fuel Injector Application Manual
Fundamentals
Delphi Energy and Chassis Systems
Revision:
11/05-1
2-1
2.0 Fundamentals
2.1
General
The Multec 3.5 Fuel Injector is a component of the Air/Fuel Subsystem.
The function of the fuel injector is to provide the required fuel quantity
and spray geometry to the each engine cylinder to meet vehicle
performance and emissions requirements over a wide range of operating
conditions. The Multec 3.5 Fuel Injector is designed for electronic port
fuel injection systems, which maintain an individual fuel injector for each
engine cylinder and operate the individual injectors via an electrical
signal. The control logic for each injector is typically governed through an
electrical control module that is provided by the customer. The customer
develops the logic with input from Delphi.
The fuel injector supply system typically consists of the fuel injectors, a
fuel rail or conduit, a fuel pressure regulator and connections to fuel
supply and return lines. This portion of the fuel system is installed directly
to the intake system of the engine. On some applications, especially
returnless fuel systems, a mechanical device for damping fuel pressure
pulsations may be incorporated to reduce fuel line "hammer". Returnless
fuel systems do not have a return line connection and typically incorporate
the pressure regulator either closer to or within the fuel supply tank. (See
Fuel Rail Applications Manual for more details.)
The vehicle fuel system includes the above mentioned injector supply
system as well as fuel supply and return (optional) lines, fuel filter, fuel
pump and fuel tank. The evaporative emissions system, while not directly
linked to the fuel injector supply system, must be considered, as vapor
purge from this system into the engine intake system will directly impact
how the fuel injector is controlled under certain conditions.