Air Induction System

PURPOSE

The air induction system supplies and controls the amount of air required by the engine for smooth operation.


OPERATION

When the engine is running, air is drawn in through an open engine air cleaner air tube mounted at the front of the engine compartment. The air then passes into the engine air cleaner assembly where dirt is filtered out by the air filter element. The filtered air then flows through and is measured by a Volume Air Flow (VAF) meter.

The VAF measures the amount of air flowing through the intake air system to the engine, and sends this information to the Powertrain Control Module (PCM). The PCM uses this information as one of the inputs to calculate fuel control.

The metered air passes through the engine air intake resonator (chamber), the air cleaner to intake manifold tube, and into the throttle body.

The air flow is regulated by the driver through the accelerator pedal and cable to the Throttle Body (TB). The throttle plate in the TB then controls the air flow as it is opened and closed by the driver, for vehicle power and engine speed demands. This metered air then enters the upper and lower intake manifolds where it is mixed with fuel for combustion.

To maintain a steady idle speed, extra air is drawn in by the Idle Air Control Bypass Air (IAC BPA) valve, bypassing the TB plate, allowing computer controlled engine idle.

To reduce intake air noise, an intake air resonator (chamber) and an intake air resonator (duct) are included in the intake air system.





During engine speeds above 5000 RPM, a High Speed Inlet Air (HSIA) system, located in the upper intake manifold, opens a series of 4 shutter valves. The opening or closing of the valves alters the intake air path. This can help improve the resonance induced inertia charging effect which will yield greater torque and a wider torque band under certain engine operating conditions.

COMPONENTS

^ Air cleaner to intake manifold tube

^ Idle air control bypass air valve hose

^ Engine air intake resonator (chamber)

^ Engine air cleaner lower assembly

^ Engine air cleaner upper assembly

^ Engine air cleaner intake tube

^ Air cleaner element

^ Engine air intake resonator (duct)

^ Volume air flow meter

^ Throttle body

^ Upper intake manifold

^ High speed inlet air shutter valves

^ Idle air control bypass air valve

^ Air cleaner outlet tube