Patent ID: 6301883
Filing Date: 2001-10-16
Classification: B60T

Abstract:
A brake booster for a vehicle having a source of vacuum, the booster having a body with a diaphragm defining a vacuum chamber and a working chamber therein and further comprising, in combination:a first conduit connecting the source of vacuum to the vacuum chamber;a vacuum pump having an activating motor;a second conduit connecting the vacuum pump in parallel with the first conduit with pump air discharge toward the source of vacuum;check valve means in the first and second conduits preventing substantial vacuum loss from the vacuum chamber through the first and second conduits, whereby a first vacuum level is normally maintained in the vacuum chamber by the source of vacuum;a sensor responsive to a vacuum level in the working chamber; andcontrol means responsive to a predetermined low value of the sensed vacuum level in the working chamber to activate the vacuum pump, whereby a second vacuum level, higher than the first vacuum level, is maintained in the vacuum chamber by the vacuum pump supplementing the source of vacuum.