Supercharger: Description and Operation

Supercharger:

DESCRIPTION
The supercharger is a positive displacement pump that consists of two counter-rotating rotors in a housing with an inlet port and an outlet port. The rotors are designed with three lobes and a helical twist. An air bypass circuit is built into the housing. The rotors in the supercharger are designed to run at a minimal clearance, not in contact with each other or the housing. The rotors are timed to each other by a pair of precision spur gears which are pressed onto the rotor shafts. The forward end of the rotors are held in position by deep groove ball bearings. The back end of the rotors are supported by sealed roller bearings.

The gears and ball bearings are lubricated by a synthetic oil. The oil reservoir is self-contained in the supercharger and does not rely on engine oil for lubrication.

The cover on the supercharger contains the input shaft which is supported by two deep groove ball bearings and is coupled to the rotor drive gears. he pulley is pressed and keyed onto the input shaft. These bearings are lubricated by the synthetic oil contained in the same reservoir as the gears and rotor bearings.

OPERATION
The supercharger is designed to pump more air than the engine would normally use. he excess air created a boost presure in the intake manifold. Maximum boost can range from 7 to 11 psi. Since the supercharger is a positive displacement pump and is directly driven from the engine accessory drive 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. The 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 three-way valve. This valve controlled by the Powertrain Control Module (PCM), determines weather 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.