Patent ID: 7040719

Claim:
A method for adjusting brake booster vacuum of an engine of a motor vehicle at a brake booster thereof, said method comprising the steps of: initially setting a brake booster pressure of the brake booster equal to a predetermined pressure; predicting brake booster vacuum; determining whether the predicted brake booster vacuum is above a threshold vacuum; modifying operation of the engine to lower a brake booster vacuum of the engine if said step of determining determines the predicted brake booster vacuum is above the threshold vacuum; and periodically repeating said steps of predicting, determining and modifying; wherein said step of predicting comprises: acquiring predetermined input variables of the motor vehicle, the variables comprising manifold absolute pressure, atmospheric pressure, and vehicle speed; determining from vehicle speed a vehicle deceleration of the motor vehicle; determining from the vehicle deceleration whether an apply brake event of the motor vehicle is occurring; determining from the vehicle deceleration whether a release brake event of the motor vehicle is occurring; determining from the vehicle deceleration whether a no brake event of the motor vehicle is occurring; obtaining a change in brake booster pressure as a function of the vehicle deceleration from an apply brake look-up table if the apply brake event is determined as occurring; obtaining a change in brake booster pressure as a function of the vehicle deceleration from a brake release look-up table if the brake release event is determined as occurring; obtaining a change in brake booster pressure set equal to zero if the no brake event of the motor vehicle is determined as occurring; and calculating brake booster vacuum responsive to the obtained change in brake booster pressure.