Fuel Delivery and Air Induction: Description and Operation

PURPOSE
The Fuel Delivery and Air Induction Systems delivers a precise amount of highly atomized fuel to the intake system to ensure optimum performance and emissions compliance.

OPERATION
The Fuel Delivery and Air Induction Systems perform this function in the following manner:

Fuel Delivery and Return
Fuel, pumped up by the Fuel Pump, flows through the Fuel Filter under pressure to the Delivery Pipe where it is distributed to each Injector.
The Fuel Pressure Regulator adjusts the pressure of the fuel from the fuel line (high pressure side) to a pressure 284 kPa (41 psi) higher than the pressure inside the intake manifold, and excess fuel is returned to the Fuel Tank through the return line.
When the engine is hot, the fuel pressure is increased to control percolation in the fuel system and improve restartability and idling stability.
The Pulsation Damper absorbs the slight fluctuations in fuel pressure caused by the Injectors. Fuel is injected into the intake manifold according to signals from the Engine Control Module (ECM). The cold start injector operates when starting at low engine coolant temperature or at normal temperature ranges, injecting fuel into the air intake chamber to improve startability.

Air Induction
Air filtered through the air cleaner passes through the volume air flow meter and the amount flowing to the air intake chamber is determined according to the throttle valve opening in the throttle body and the RPM. The volume air flow meter measures the air intake flow to the engine by the swirl frequency.
Located in the throttle body is the throttle valve, which regulates the volume of air intake to the engine. Air intake controlled by the throttle valve opening is distributed from the intake chamber to the manifold of each cylinder and is drain into the combustion chamber.
At low air temperature the idle air control valve opens and the air flows through the idle air control valve, as well as the throttle body, into the air intake chamber. During engine warm up, even if the throttle valve is completely closed, air flows to the air intake chamber, thereby increasing the idle speed (first idle operation).
The air intake chamber prevents pulsation of the intake air, reduces the influence on the volume air flow meter and increases the air intake volume. It also prevents intake air interference in each cylinder.