A method for a hybrid-electric vehicle may comprise, while the hybrid-electric vehicle is moving and in an absence of fuel being directed to an engine, directing engine intake air through an ejector to supply vacuum to a brake booster independent of a brake booster vacuum.

A method for actuating an electric vacuum pump of a brake booster including indirectly ascertaining a negative pressure in the brake booster. Depending on the indirectly ascertained negative pressure, and on a pumping capacity of the vacuum pump, ascertaining at least one activation parameter for the vacuum pump. Activating the vacuum pump in accordance with the activation parameter, when the indirectly ascertained negative pressure drops below a predefined minimum value.

A method for actuating an electric vacuum pump of a brake booster including indirectly ascertaining a negative pressure in the brake booster. Depending on the indirectly ascertained negative pressure, and on a pumping capacity of the vacuum pump, ascertaining at least one activation parameter for the vacuum pump. Activating the vacuum pump in accordance with the activation parameter, when the indirectly ascertained negative pressure drops below a predefined minimum value.

Methods and systems are provided for controlling an aspirator shut-off valve in an engine of a hybrid vehicle. One example method includes opening the aspirator shut-off valve following a shut-down command to the engine when engine speed is between a first engine speed and a second engine speed, the first engine speed being lower than an idle speed and the second engine speed occurring before an imminent engine stop. The example method further includes not opening the aspirator shut-off valve between the first engine speed and the second engine speed if an oxygen content of an emission control device is at or near a threshold.

Methods and systems are provided for controlling an aspirator shut-off valve in an engine of a hybrid vehicle. One example method includes opening the aspirator shut-off valve following a shut-down command to the engine when engine speed is between a first engine speed and a second engine speed, the first engine speed being lower than an idle speed and the second engine speed occurring before an imminent engine stop. The example method further includes not opening the aspirator shut-off valve between the first engine speed and the second engine speed if an oxygen content of an emission control device is at or near a threshold.

A method is described for operating a hydraulic braking device of a vehicle, in particular a motor vehicle, including at least one brake booster, which sets a brake boost as a function of a driver's braking command. It is provided that the driver's braking command is ascertained via a vacuum sensor assigned to a pneumatic brake booster and a hydraulic brake boost is set.

A method is described for operating a hydraulic braking device of a vehicle, in particular a motor vehicle, including at least one brake booster, which sets a brake boost as a function of a driver's braking command. It is provided that the driver's braking command is ascertained via a vacuum sensor assigned to a pneumatic brake booster and a hydraulic brake boost is set.

A device for varying a pedal resistance of a hydraulic brake system includes at least one electroactive polymer actuator. The device further includes a reaction disc. The reaction disc has at least two polymer actuators. The at least two polymer actuators are independently controllable. Additionally, the at least two polymer actuators are arranged coaxially relative to one another.

A device for varying a pedal resistance of a hydraulic brake system includes at least one electroactive polymer actuator. The device further includes a reaction disc. The reaction disc has at least two polymer actuators. The at least two polymer actuators are independently controllable. Additionally, the at least two polymer actuators are arranged coaxially relative to one another.

Methods and systems are provided for providing vacuum to a brake booster via an aspirator system. In one example, a system may include an aspirator system fluidly coupled with a brake booster with no intervening components located therebetween.