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).

Air Induction
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 drawn into the combustion chamber.
Under normal operating conditions the Idle Air Control (IAC) Valve allows air flow to bypass the throttle plate and, as controlled by the ECM, regulates the idle speed. During engine warm up, fast idle is accomplished by air flowing into the intake chamber also via the IAC Valve, even when the throttle valve is completely closed. In this way the IAC Valve controls the idle speed to suit all operating conditions.
The air intake chamber prevents pulsation of the intake air and reduces the influence on the Volume Air Flow Meter and increases the air intake volume. It also prevents intake air interference in each cylinder. There is also the Intake Air Control Valve attached to the air intake chamber which is part of the Acoustic Control Induction System (ACIS). The Engine Control Module provides signals to the Vacuum Switching Valve (VSV) to open or close. The VSV opens or closes the vacuum source to the actuator, which in turn opens or closes the Intake Air Control Valve. The Intake Air Control Valve is designed to modify the effective manifold length in 2 stages for increased power in all driving ranges.