Supercharger Description and Operation: Operation

The supercharger is designed to pump more air than the engine would normally use. This excess air creates a boost pressure in the intake manifold. Maximum engine boost is 83 kPa (12 psi). Because the supercharger is a positive displacement pump and is directly driven from the engine drive belt system, boost pressure is available at all driving conditions.

When boost is not desired, such as during idle and light throttle cruising, the excess air that the supercharger is producing is routed through the bypass passage between the intake manifold and the supercharger inlet. This bypass circuit is regulated by a bypass valve which is similar to a throttle plate. The bypass valve is controlled by a vacuum actuator which is connected to the vacuum signal between the throttle and the supercharger inlet. Spring force from the actuator holds the valve closed to create boost, and vacuum pulls the valve open when the throttle closes to decrease boost. The open bypass valve reduces pumping loss thereby increasing fuel efficiency.

The solenoid valve attached to the bypass actuator is an electronically controlled, 3-way valve. This valve, controlled by the powertrain control module (PCM), determines whether pressure from the manifold is routed to the bypass actuator or closed off. The valve allows pressure from the manifold to open the bypass valve and regulate boost pressure during specific driving conditions.