Brake system

A method of braking a vehicle incorporating a brake system in an X brake circuit splitting configuration, the brake system comprising:

• an actuating device,
• a first piston-cylinder unit, enabled to be actuated by means of the actuating device, and arranged to supply pressure medium to one or more brake circuits via a first valve device,
• wherein the first piston-cylinder unit has a floating piston which separates a first working chamber and a second working chamber from one another,
• a second piston-cylinder unit comprising a pressure chamber, an electromotive drive and a transmission, wherein the electromotive drive is arranged to drive a piston for supplying pressure medium to at least one of the one or more brake circuits via a second valve device, and
• a motor-pump unit with a third valve device, configured to supply pressure medium to the one or more brake circuits,
• wherein, by means of a control device, the motor of the electromotive drive of the second piston-cylinder unit and the motor of the motor-pump unit are enabled to be used,
• wherein the motor-pump unit is connected via two hydraulic connections to the first working chamber and to the second working chamber,
• wherein an isolating valve is arranged only in one of the two hydraulic connections, or wherein a respective isolating valve is arranged in each of the two hydraulic connections for the purposes of selectively opening or closing the respective hydraulic connection,
• wherein the second piston-cylinder unit is connected to the respective hydraulic connections via respective valves to enable a pressure change to be performed in at least one of the one or more brake circuits,
• wherein the second piston-cylinder unit is only effective in a specific pressure range, and
• wherein the motor-pump unit is used for pressure generation for a further pressure range that is higher than the specific pressure range,
• the method comprising:
• closing the isolating valve in the one of the two hydraulic connections corresponding to a first brake circuit of the one or more brake circuits when a front wheel of the first brake circuit shows a tendency to lock, wherein the one or more brake circuits include first and second brake circuits, and
• increasing pressure in the second brake circuit of the one or more brake circuits, following said closing the isolating valve, until a rear wheel of the second brake circuit shows a tendency to lock.

A method of braking a vehicle incorporating a brake system in an II brake circuit splitting configuration, the vehicle further having front and rear axles having respective wheels, and wherein the one or more brake circuits include a first brake circuit and a second brake circuit, wherein the brake system comprises:

• an actuating device,
• a first piston-cylinder unit, enabled to be actuated by means of the actuating device, and arranged to supply pressure medium to one or more brake circuits via a first valve device,
• wherein the first piston-cylinder unit has a floating piston which separates a first working chamber and a second working chamber from one another,
• a second piston-cylinder unit comprising a pressure chamber, an electromotive drive and a transmission, wherein the electromotive drive is arranged to drive a piston for supplying pressure medium to at least one of the one or more brake circuits via a second valve device, and
• a motor-pump unit with a third valve device, configured to supply pressure medium to the one or more brake circuits,
• wherein, by means of a control device, the motor of the electromotive drive of the second piston-cylinder unit and the motor of the motor-pump unit are enabled to be used,
• wherein the motor-pump unit is connected via two hydraulic connections to the first working chamber and to the second working chamber,
• wherein an isolating valve is arranged only in one of the two hydraulic connections, or
• wherein a respective isolating valve is arranged in each of the two hydraulic connections for the purposes of selectively opening or closing the respective hydraulic connection,
• wherein the second piston-cylinder unit is connected to the respective hydraulic connections via respective valves to enable a pressure change to be performed in at least one of the one or more brake circuits,
• wherein the second piston-cylinder unit is only effective in a specific pressure range, and
• wherein the motor-pump unit is used for pressure generation for a further pressure range that is higher than the specific pressure range,
• the method comprising:
• (a) closing the isolating valve in the one of the two hydraulic connections corresponding to the first brake circuit when the wheels on the front axle of the vehicle, which are assigned to the first brake circuit, show a tendency to lock, and
• operating the second piston-cylinder unit to increase brake pressure in wheel brake cylinders on the rear axle of the vehicle, which are assigned to the second brake circuit, until the wheels on the rear axle also show a tendency to lock;
• or
• (b) closing the isolating valve in the one of the two hydraulic connections corresponding to the second brake circuit when the wheels on the rear axle show a tendency to lock;
• and
• operating the second piston-cylinder unit to increase brake pressure in wheel brake cylinders on the front axle, which are assigned to the first brake circuit, until the wheels on the front axle also show a tendency to lock.

A method of braking a vehicle incorporating a brake system in an X brake circuit splitting configuration, wherein the brake system comprises:

• an actuating device,
• a first piston-cylinder unit, enabled to be actuated by means of the actuating device, and arranged to supply pressure medium to one or more brake circuits via a first valve device,
• wherein the first piston-cylinder unit has a floating piston which separates a first working chamber and a second working chamber from one another,
• a second piston-cylinder unit comprising a pressure chamber, an electromotive drive and a transmission, wherein the electromotive drive is arranged to drive a piston for supplying pressure medium to at least one of the one or more brake circuits via a second valve device, and
• a motor-pump unit with a third valve device, configured to supply pressure medium to the one or more brake circuits,
• wherein, by means of a control device, the motor of the electromotive drive of the second piston-cylinder unit and the motor of the motor-pump unit are enabled to be used,
• wherein the motor-pump unit is connected via two hydraulic connections to the first working chamber and to the second working chamber,
• wherein an isolating valve is arranged only in one of the two hydraulic connections, or wherein a respective isolating valve is arranged in each of the two hydraulic connections for the purposes of selectively opening or closing the respective hydraulic connection,
• wherein the second piston-cylinder unit is connected to the respective hydraulic connections via respective valves to enable a pressure change to be performed in at least one of the one or more brake circuits,
• wherein the second piston-cylinder unit is only effective in a specific pressure range, and
• wherein the motor-pump unit is used for pressure generation for a further pressure range that is higher than the specific pressure range, and
• wherein the one or more brake circuits consist of first and second brake circuits, each of the first and second brake circuits being associated with a respective front wheel and a respective rear wheel of the vehicle,
• the method comprising:
• closing the isolating valve in the one of the two hydraulic connections corresponding to the first brake circuit when the front wheel of the first brake circuit shows a tendency to lock, and
• increasing pressure in the second brake circuit while said isolating valve is closed until the rear wheel of the second brake circuit shows a tendency to lock.

A method of braking a vehicle incorporating a brake system in an X brake circuit splitting configuration, the brake system comprising:

• an actuating device,
• a first piston-cylinder unit, enabled to be actuated by means of the actuating device, and
• arranged to supply pressure medium to one or more brake circuits via a first valve device,
• wherein the first piston-cylinder unit has a floating piston which separates a first working chamber and a second working chamber from one another,
• a second piston-cylinder unit comprising a pressure chamber, an electromotive drive and a transmission, wherein the electromotive drive is arranged to drive a piston for supplying pressure medium to at least one of the one or more brake circuits via a second valve device, and
• a motor-pump unit with a third valve device, configured to supply pressure medium to the one or more brake circuits,
• wherein, by means of a control device, the motor of the electromotive drive of the second piston-cylinder unit and the motor of the motor-pump unit are enabled to be used,
• wherein the motor-pump unit is connected via two hydraulic connections to the first working chamber and to the second working chamber,
• wherein an isolating valve is arranged only in one of the two hydraulic connections, or wherein a respective isolating valve is arranged in each of the two hydraulic connections for the purposes of selectively opening or closing the respective hydraulic connection,
• wherein the second piston-cylinder unit is connected to the respective hydraulic connections via respective valves to enable a pressure change to be performed in at least one of the one or more brake circuits,
• wherein the second piston-cylinder unit is only effective in a specific pressure range, and
• wherein the motor-pump unit is used for pressure generation for a further pressure range that is higher than the specific pressure range, and
• wherein the one or more brake circuits consist of first and second brake circuits, each of the first and second brake circuits being associated with a respective front wheel and a respective rear wheel of the vehicle,
• the method comprising:
• closing the isolating valve in the one of the two hydraulic connections corresponding to the second brake circuit when the front wheel of the second brake circuit shows a tendency to lock, and
• increasing pressure in the first brake circuit while said isolating valve is closed until the rear wheel of the first brake circuit shows a tendency to lock.

A method of braking using a brake system wherein the brake system comprises:

• an actuating device,
• a first piston-cylinder unit, enabled to be actuated by means of the actuating device, and
• arranged to supply pressure medium to one or more brake circuits via a first valve device,
• wherein the first piston-cylinder unit has a floating piston which separates a first working chamber and a second working chamber from one another,
• a second piston-cylinder unit comprising a pressure chamber, an electromotive drive and a transmission, wherein the electromotive drive is arranged to drive a piston for supplying pressure medium to at least one of the one or more brake circuits via a second valve device, and
• a motor-pump unit with a third valve device, configured to supply pressure medium to the one or more brake circuits,
• wherein, by means of a control device, the motor of the electromotive drive of the second piston-cylinder unit and the motor of the motor-pump unit are enabled to be used,
• wherein the motor-pump unit is connected via two hydraulic connections to the first working chamber and to the second working chamber,
• wherein an isolating valve is arranged only in one of the two hydraulic connections, or wherein a respective isolating valve is arranged in each of the two hydraulic connections for the purposes of selectively opening or closing the respective hydraulic connection,
• wherein the second piston-cylinder unit is connected to the respective hydraulic connections via respective valves to enable a pressure change to be performed in at least one of the one or more brake circuits,
• wherein the second piston-cylinder unit is only effective in a specific pressure range, and
• wherein the motor-pump unit is used for pressure generation for a further pressure range that is higher than the specific pressure range, and
• wherein the brake system includes four wheel brake cylinders,
• the method comprising:
• performing a recuperation with a same brake pressure in all four wheel brake cylinders by building up pressure and reducing pressure by the second piston-cylinder unit, wherein a target brake pressure is set by the second piston-cylinder unit, wherein when a target braking force is greater than a maximum electrical braking force, the target braking force is a difference between the target braking force and the electrical braking force and the target brake pressure is calculated from the target braking force using individual Cp values, which are ratios of brake force to brake pressure, of the wheel brakes, and wherein when the target braking force is less than or equal to the maximum electrical braking force, a hydraulic braking force has 0 N, such that braking is performed exclusively electrically.