Abstract: A vehicle includes a user-actuatable switch and a controller. When the switch is actuated, the controller is adapted to effect a regenerative braking command to actuate a regenerative brake system when a vehicle speed is above a threshold speed, and to effect a parking brake command to actuate an electric park brake when the vehicle speed is less than or equal to the threshold speed.

Abstract: A vehicle includes a user-actuatable switch and a controller. When the switch is actuated, the controller is adapted to effect a regenerative braking command to actuate a regenerative brake system when a vehicle speed is above a threshold speed, and to effect a parking brake command to actuate an electric park brake when the vehicle speed is less than or equal to the threshold speed.

Abstract: 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.

Abstract: Methods and apparatus to control braking of a vehicle during low deceleration operations are disclosed. A disclosed apparatus includes a controller configured to determine a deceleration of a vehicle, compare the deceleration to a threshold, and modulate, at a predetermined frequency, a brake pressure of the vehicle in response to the deceleration being below the threshold.

Abstract: 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.

Abstract: 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.

Abstract: A vacuum source arbitration system is disclosed. In one example, vacuum is supplied to a vacuum reservoir via an ejector during a first condition, and vacuum is supplied to the vacuum reservoir via an engine intake manifold during a second condition. The approach may provide a desired level of vacuum in a reservoir while reducing engine fuel consumption.

Abstract: Methods and systems are provided to reduce a hard brake pedal feel. A brake control variable is adjusted in anticipation of a hard pedal condition to increase hydraulic brake line pressure and maintain a normal pedal feel. A pedal force is inferred from brake line pressure relative to brake booster vacuum.

Abstract: 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.

Abstract: A vacuum source arbitration system is disclosed. In one example, vacuum is supplied to a vacuum reservoir via an ejector during a first condition, and vacuum is supplied to the vacuum reservoir via an engine intake manifold during a second condition. The approach may provide a desired level of vacuum in a reservoir while reducing engine fuel consumption.

Abstract: Methods and systems are provided to reduce a hard brake pedal feel. A brake control variable is adjusted in anticipation of a hard pedal condition to increase hydraulic brake line pressure and maintain a normal pedal feel. A pedal force is inferred from brake line pressure relative to brake booster vacuum.

Abstract: A vacuum source arbitration system is disclosed. In one example, vacuum is supplied to a vacuum reservoir via an ejector during a first condition, and vacuum is supplied to the vacuum reservoir via an engine intake manifold during a second condition. The approach may provide a desired level of vacuum in a reservoir while reducing engine fuel consumption.

Abstract: Methods and systems are provided to reduce a hard brake pedal feel. A brake control variable is adjusted in anticipation of a hard pedal condition to increase hydraulic brake line pressure and maintain a normal pedal feel. A pedal force is inferred from brake line pressure relative to brake booster vacuum.

Abstract: In the event that the brake pedal and accelerator pedal are depressed simultaneously, powertrain output is decreased monotonically with brake pedal input. In a lower range of brake pedal input, the brakes are prevented from actuating or are allowed to actuate minimally. In a higher range of pedal input, the powertrain output continues to be decreased and the brakes are allowed to actuate. In yet another higher range of pedal input, the powertrain output is substantially decreased such that a minimal powertrain output is achieved. The powertrain may include an internal combustion engine and/or an electric motor. The brake pedal input is determined based on a sensor associated with the brake pedal, the brake booster, or the master cylinder.

Abstract: Methods and systems are provided to reduce a hard brake pedal feel. A brake control variable is adjusted in anticipation of a hard pedal condition to increase hydraulic brake line pressure and maintain a normal pedal feel. A pedal force is inferred from brake line pressure relative to brake booster vacuum.

Abstract: A vacuum source arbitration system is disclosed. In one example, vacuum is supplied to a vacuum reservoir via an ejector during a first condition, and vacuum is supplied to the vacuum reservoir via an engine intake manifold during a second condition. The approach may provide a desired level of vacuum in a reservoir while reducing engine fuel consumption.

Abstract: Power brakes are typically vacuum assisted, with the vacuum provided from the intake manifold. If the engine is commanded to operate for a long period at a condition with low intake manifold vacuum, the vacuum within the brake booster may drop to a level which is marginal or insufficient for a present or subsequent braking operation. To ensure sufficient vacuum in the intake manifold to provide to the brake booster, the engine may be commanded to operate at a condition to increase intake manifold vacuum by one of: adjusting cam timing, increasing engine speed, and increasing EGR. In the case of a stop-start vehicle, the engine speed is increased from zero to a condition that provides the desired vacuum.

Abstract: In the event that the brake pedal and accelerator pedal are depressed simultaneously, powertrain output is decreased monotonically with brake pedal input. In a lower range of brake pedal input, the brakes are prevented from actuating or are allowed to actuate minimally. In a higher range of pedal input, the powertrain output continues to be decreased and the brakes are allowed to actuate. In yet another higher range of pedal input, the powertrain output is substantially decreased such that a minimal powertrain output is achieved. The powertrain may include an internal combustion engine and/or an electric motor. The brake pedal input is determined based on a sensor associated with the brake pedal, the brake booster, or the master cylinder.