VACUUM BOOST FOR VEHICLE BRAKING

摘要

Methods for controlling vacuum within a brake booster by modifying powertrain operation include determining an intake manifold vacuum in response to actuation of a brake pedal. Increasing the intake manifold vacuum if the brake booster vacuum is less than a desired brake booster vacuum. In some embodiments, the transmission is downshifted to increase engine speed and intake manifold vacuum. In other embodiments, engine torque is reduced to increase intake manifold vacuum and the torque of the electric machine is increased to maintain a constant output torque.

主权项

1. A method for controlling brake vacuum within a brake booster on a vehicle that includes an engine and a transmission, comprising:
determining an intake manifold vacuum in response to actuation of a brake pedal; downshifting the transmission to increase engine speed and intake manifold vacuum when the intake manifold vacuum is less than a desired brake booster vacuum; and reducing torque of the engine to maintain a constant power output of the engine.