Self contained, supplemental vacuum assist unit for vehicle brake booster

A self contained, supplemental vacuum assist unit is provided for use with a vacuum brake booster and a source of vacuum in a motor vehicle. The unit includes, within a single housing, an electric motor, an air pump driven by the motor, a manifold defining air exhaust and assist vacuum chambers, a pair of check valves permitting air flow from the pump outlet and the assist vacuum chamber to the air exhaust chamber, an outlet from the air exhaust chamber with a fitting for connection to the vacuum source, an opening from the assist vacuum chamber with a fitting providing communication directly to the interior of the vacuum chamber of the booster, and a pressure sensor including a diaphragm, plunger, magnet with a Hall effect sensor and motor control circuitry on a circuit board within the assist vacuum chamber. The unit is compact, light weight and efficient and is designed for attachment directly to the booster with no intervening vacuum hose therebetween.