WO2018130480A1

WO2018130480A1 - Brake system for a motor vehicle and two methods for the operation thereof

Info

Publication number: WO2018130480A1
Application number: PCT/EP2018/050324
Authority: WO
Inventors: Jochen Zimmermann
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 2017-01-11
Filing date: 2018-01-08
Publication date: 2018-07-19
Also published as: DE102017222435A1

Abstract

The invention relates to a brake system for a motor vehicle, having at least four hydraulically actuatable wheel brakes (8a-8d), a simulation device (3), an electrically actuatable inlet valve (6a-6d) for each wheel brake (8a-8d), a first electrically controllable pressure-providing device (5), which is separably hydraulically connected to a brake supply line (13) by means of a separating valve (26), to which brake supply line the wheel brakes (8a-8d) are connected, and a second electrically controllable pressure-providing device (2), which is hydraulically connected to the brake supply line (13), wherein an electrically actuatable circuit separation valve (40) is arranged in the brake supply line (13) in such a way that, when the circuit separation valve is closed, the brake supply line (13) is hydraulically divided into a first and a second line section (13a, 13b), wherein the first line section (13a) is hydraulically connected to two of the inlet valves (6a, 6b) and the second line section (13b) is hydraulically connected to the other inlet valves (6c, 6d), and wherein the second pressure-providing device (2) is hydraulically connected to the first line section (13a) and the first pressure-providing device (5) is hydraulically connected to the second line section (13b) by means of the separating valve (26), wherein the second pressure-providing device (2) comprises a suction connection point (23) and a pressure connection point (27), wherein an overflow valve (32) is provided for setting or controlling the pressure provided by the second pressure-providing device (2), by means of which overflow valve the pressure connection point (27) is hydraulically connected to the suction connection point (23). The invention further relates to methods for operating such a brake system.

Description

BRAKING SYSTEM FOR A MOTOR VEHICLE AND TWO METHOD OF OPERATING THEREOF

The invention relates to a brake system according to the preamble of claim 1 and a method for operating a brake system.

From DE 102013223 859 AI is a brake system with hydraulically actuated wheel brakes and an actuated by means of a brake pedal simulation device, with no mechanical and / or hydraulic operative connection between the brake pedal and the wheel brakes is provided. It is a single electrically controllable pressure source with a stepped piston and two Dich ^¬ telementen provided in order to achieve increased availability of the brake system.

From DE 10 2013 217 954 AI a brake system with two electrically controllable pressure supply device and a Kreistrennventil is known, for a purely mecha ^¬ African / hydraulic fallback a brake pedal-operated master cylinder is present, which is connected to the wheel brakes. A simulation device is with the

Master cylinder hydraulically connected. The pressure-providing devices are both designed as a linear actuator, in which a brake pressure is set by moving a piston back and forth by means of an electric motor with a downstream rotational-translation gear. Should u.ä. in the linear actuator or its control. there is a systematic error or weak point, there is a relatively high risk that both linear actuators could fail at the same time.

The object of the present invention to provide a suitable bereitzu ^¬ for highly automated driving Brake system which is simple and inexpensive, but which offers the highest possible availability for highly automated driving. In particular, should be able to dispense with a brake pedal-operated master cylinder.

This object is achieved by a brake system according to claim 1 and a method according to claim 14 or 15.

The invention is based on the idea to provide a brake system for a motor vehicle with a simulation device, a first electrically controllable pressure supply device, which is hydraulically connected separably via a separating valve with a brake supply line to which the wheel brakes are connected via in each case one of the inlet valves, and a second electrically controllable pressure supply device which is hydraulically connected to the brake supply line, wherein in the brake supply line, an electrically operable Kreistrennventil is arranged such that when the closed Kreistrennventil the Bremsver- sorgungsleitung is hydraulically separated into a first line section and a second line section, wherein the first line section with two the inlet valves is hydraulically connected and the second line section is hydraulically connected to the remaining inlet valves, and wherein the second Druckbereitst ellungseinrichtung with the first line segment is hydraulically connected and the first Ready to print ^¬ provision device is hydraulically connected via the diverter valve with the second line section, wherein the second pressure generating device comprises a suction connection and a pressure connection and an overflow valve provided for adjusting or regulating the pressure provided by the second pressure generating device is, via which the pressure port is hydraulically connected to the suction port. The overflow valve is thus, so to speak, the second pressure Positioning device connected in parallel.

The invention provides the advantage that can be autonomous or performed by an autopilot function even after a fatal error such as a failure of one of the electrically controllable pressure supply facilities, the main brake functions, aufzu build particular delay ^¬ comply with the blocking order of the vehicle axles and a destabilizing at to prevent high delays, as well as maintain controllability. For this purpose radin ^¬ individual and at least individual brake circuit pressures are not ^¬ agile and the setting of respective precise brake pressure curves including pressure build-up, pressure reduction and pressure hold. The brake system is thus particularly suitable for the realization of highly automated driving functions. A fallback with a driver-operated master cylinder is therefore not necessary.

The pressure connection of the second pressure-ready position device is preferably connected to the first line section.

The brake system preferably comprises a pressure medium reservoir, in particular under atmospheric pressure. Particularly preferably, the suction connection of the second pressure ^preparation device is connected to the pressure medium reservoir.

The overflow valve is preferably arranged in a hydraulic connection between the pressure connection of the second pressure supply device or the first line section and the pressure medium reservoir.

In addition to the wheel brake individual intake valves includes the Brake system preferably an electrically actuated exhaust valve per wheel brake. By means of the exhaust valve, the associated wheel brake is connected to the, in particular at atmospheric pressure ste ^¬ henden, pressure medium reservoir to allow wheel individual pressure reduction on the wheel by opening the exhaust valve, in particular at a pressure ^¬ provision by the second pressure supply device. Particularly preferably, the outlet valves are connected to the pressure medium reservoir via a common hydraulic connection. Particularly preferably, the wheel-specific brake pressures are derived from a brake supply pressure in the brake supply line, wherein in an inoperative state, the intake valves forward the brake ^{supply ¬} pressure to the wheel brakes and lock the exhaust valves outflow of pressure fluid from the wheel brakes.

The overflow valve is preferably closed off from ^¬ out to prevent flow of pressure medium via the overflow valve in the pressure medium reservoir, for example, at a pressure buildup by means of the first pressure supply device, without a control / switching of the spill valve is necessary. So can be dispensed with a further isolation valve, via which the second

Pressure supply device to the brake supply line or the first line section separable hydraulically connected. The overflow valve is particularly preferably designed to be adjustable analogously in order to ensure a precise pressure position by means of the second pressure supply device, e.g. in case of failure of the first pressure supply device, to be possible.

In order to avoid flow resistance, the second pressure ^{¬ supply device} is preferably connected directly to the first line section hydraulically. This means that no electrically operable valve is arranged hydraulically between the second pressure supply device or its pressure connection and the first line section.

Advantageously, no valve is arranged between the second pressure supply device or its pressure connection and the first line section.

The brake system comprises a simulation device for conveying a brake pedal feeling to a driver. Preferably, the simulation device is by means of a

Brake pedal actuated and there is no mechanical and / or hydraulic operative connection between the brake pedal and the wheel brakes provided. Particularly preferred are the simu ^¬ lationseinrichtung includes a piston, for example, which is mechanically connected via a push rod to the brake pedal, and coupled, that is, which is directly connected to the brake pedal.

The simulation device is preferably hydraulically connected to none of the wheel brakes. The brake system preferably does not include a brake master cylinder master cylinder which is connected to one of the wheel brakes.

Preferably, the brake system comprises hydraulically actuated wheel brake for four wheels, which are distributed to a first vehicle axle and a second vehicle axle. The wheel brakes connected to the first line section are particularly preferably associated with the first vehicle axle, advantageously the front axle, and the wheel brakes connected to the second line section are associated with the second vehicle axle, advantageously the rear axle.

Preferably, the second pressure supply device is formed by a piston pump, particularly preferably by a radial piston pump. This many years in automotive brake The proven and optimized type of pump can be used in the brake system, since the overflow valve allows a

Pressure limitation or pressure reduction with sufficient

Speed and precision can be performed to provide the above-mentioned key brake functions in case of failure of the first pressure supply device. Piston pumps are inexpensive to produce and are based on known technologies, so that their use also represents a very low development risk for the brake system.

Preferably, the second pressure supply device is formed by a piston pump, while the first Druckbereit ^¬ positioning device is formed by a cylinder-piston assembly with a hydraulic pressure chamber whose piston is actuated by an electromechanical actuator, the piston for pressure buildup by means of the electromechanical actuator and driven forward is reduced for pressure reduction by means of the electromechanical actuator. Since first and second Druckbe ^¬ provision device using a complementary technology, the risk of a simultaneous failure of both pressure-providing devices is reduced due to a systematic error.

The circular selector valve is preferably designed to be normally open. Thus, all wheel brakes without energizing / switching the circular valve from the first or the second pressure supply device can be pressurized. However, the brake system can be separated, for example in the case of leakage, by closing the circular valve in a first hydraulic brake circuit and a second hydraulic brake circuit. The first hydraulic brake circuit comprises the second pressure supply device with the overflow valve, the first line section, as well as two of the wheel brakes with the associated two inlet valves. The second hydraulic Brake circuit includes the first pressure supply device, the isolation valve, the second line section and the other wheel brakes with the associated inlet valves. Preferably, the pressure medium level of the pressure ^fluid reservoir ^{¬ is} detected by means of a measuring device in order to detect a leak and possibly make a Kreistrennung.

The isolation valve is preferably designed to be normally open. Thus, the wheel brakes without energizing / switching the isolation valve can be acted upon by the first pressure supply device with a pressure. In case of failure of the first

Pressure supply device can, in particular to prevent a loss of pressure medium volume, the first pressure supply device are separated by closing the separating valve hydraulically from the brake supply line.

The first pressure supply device is preferably by a cylinder-piston arrangement with a hydraulic

Pressure chamber formed, the piston is actuated by an electromechanical actuator, wherein the pressure chamber is connected in an unactuated state of the piston via at least one Schnüffelloch and a conduit to the pressure medium reservoir, said compound is separated upon actuation of the piston. Such a cylinder-piston arrangement can be a

Providing the brake pressure curve by moving the piston back and forth by means of the electromechanical actuator with high dynamics and precision. Particularly preferably, the electromechanical actuator comprises an electric motor with a downstream rotation-translation gear.

Particularly preferably, the first pressure ^{supply ¬} device comprises a single pressure chamber, wherein the pressure chamber via exactly one separating valve, namely the separating valve, with the Brake supply line is separably connected.

The brake system preferably comprises a first electronic device, by means of which the first Druckbereitstellungs- device is controlled, and a second electronic device, by means of which the second pressure ^{supply ¬} device is controlled. In this case, the second electronic device is electrically independent of the first electronic device, so that an electrical or electronic fault in one of the electronic devices does not lead to failure of both electronic devices.

The two electronic devices are electrically independent of each other in the sense that failure of the first electronic device does not cause failure of the second electronic device, and vice versa, i. the two electronic devices are galvanically isolated.

Preferably, the first electronic device is powered by a first electrical power supply or comprises a first electrical power supply. The second electronic device is powered by a second electric energy supply and comprises a second electrical Ener ^¬ gieversorgung. In this case, the first electrical energy supply is independent of the second electrical energy supply.

The two electronic devices can be arranged in a common housing or on a common circuit board, for example in a common electronic control unit (ECU). Alternatively the two elekt ^¬ tronic devices may be arranged in two separate housings or on two separate printed circuit boards, for example in the two electronic control units. The first electronic device is designed to actuate or control the first pressure supply device. Preferably, the first pressure ^{supply ¬} device is also supplied by the first electronic device with electrical energy. Accordingly, the second pressure supply device is actuated or activated by means of the second electronic device. Preferably, the second pressure supply device is also supplied by the second electronic device with electrical energy.

The overflow valve and the separating valve are preferably controlled by means of the second electronic device or supplied with electrical energy. Thus, if the first pressure supply device or the first electronic device or the first energy supply fails, a hydraulic separation of the first pressure supply direction and a pressure control of the brake pressure provided by the second pressure supply device for the wheel brakes are possible by closing the separating valve by means of the second electronic device, the second pressure-providing device is actuated and the overflow valve is activated. The overflow valve and the separating valve are particularly preferably activated or actuated exclusively by means of the second electronic device in order to dispense with more expensive, double-controllable valves.

The intake valves, and if present the exhaust valves, are preferably energized by the second electronic device. Thus, in the event of failure of the first pressure supply device or the first electronic device or the first energy supply, wheel-individual brake pressure curves can still be made by means of the second electronic device. The inlet valves and, if present, the outlet valves valves, are particularly preferably driven exclusively by means of the second electronic device or. operated in a cost-intensive, double controllable valves to dispense ^¬ ver.

The brake system comprises according to a preferred embodiment, a wheel speed sensor for each wheel associated with a wheel or is connected to such. In this case, the wheel speed sensors are preferably supplied and / or evaluated by means of the second electronic device with electrical energy. Thus, in the event of a failure of the first electronic device, the wheel speeds of the second electronic device necessary for the wheel-specific brake pressure control are available. Particularly preferably, the wheel speed sensors are supplied and / or evaluated exclusively by means of the second electronic device with electrical energy. Thus, redundant wheel speed sensors and the associated signal connections are saved to the first electronic device.

The Kreistrennventil is preferably controlled by means of the first electronic device or supplied with electrical energy. Thus, in the event of failure of the second pressure supply device or the second electronic device or the second energy supply, brake circuit individual (ie brake circuit different) brake pressure curves can be made by the first Druckbereitstellungsei- direction and the Kreistrennventil be operated by means of the first electronic device. The brake circuit different brake pressures are adjusted by a brake circuit multiplex method. With appropriate assignment of the wheel brakes to the axles of the motor vehicle achsinduelle Bremsdruck ^¬ courses and an achsweises screens are possible by means of the Kreistrennventils. The circular selector valve is particularly preferably activated or actuated exclusively by means of the first electronic device or supplied with electrical energy in order to dispense with a more costly, double-controllable valve.

The brake system comprises according to a further preferred embodiment, a driving dynamics sensor or connected to such. The vehicle dynamics sensor system particularly preferably comprises at least one measuring device for detecting one or more of the following variables: longitudinal acceleration, in particular

Vehicle longitudinal acceleration; Lateral acceleration, in particular vehicle lateral acceleration; Yaw rate; Steering angle. In this case, the vehicle dynamics sensor system is preferably supplied and / or evaluated with electrical energy by means of the first electronic device. So are available in case of failure of the second elekt ^¬ tronic device necessary for the individual brake circuit the brake pressure control and maintain the stability of driving dynamic variables of the first electronic device. The vehicle dynamics sensor system is particularly preferably supplied and / or evaluated exclusively by means of the first electronic device with electrical energy. Thus, redundant sensors / measuring devices and the associated signal connections are saved to the second electronic device.

The brake system according to the invention is "brake-by-wire" type. Preferably includes the simulation device to the driver's intention detecting a first, preferably redundantly ^¬ led sensor for detecting a first physical quantity which characterizes the braking request of the driver, and a second, preferably redundantly executed, sensor for detecting a different, second physical quantity, which characterizes the braking request of the driver Size can be a walk and the second size a push or a force.

The invention also relates to a method for operating a brake system according to the invention.

The separating valve are preferred in case of failure of the first pressure-supplying ^¬ provision means or the first electronic device or the first power supply closed, a means of the second pressure generating device

Pressure build-up performed and adjusted by means of the intake valves (6a-6d), and if present the exhaust valves, and the spill valve wheel-specific brake pressures at the wheel brakes. This is particularly preferably carried out by means of the second electronic device, which operates the second pressure READY ^¬ averaging means and the inlet valves, the isolation valve and the overflow valve and, if present, the exhaust valves controls, respectively. In the event of a failure of the second pressure- ^ready device or the second electronic device or the second energy supply, pressure buildup is preferably carried out by means of the first pressure supply device and individual, ie brake circuit-individual, brake pressures are set at the wheel brakes by means of the circular valve for the first and the second line sections. This is particularly preferably carried out by means of the first electronic device, which activates or actuates the first pressure supply device and the circular valve.

Further preferred embodiments of the invention will become apparent from the dependent claims and the following description with reference to a figure. It shows schematically

Fig. 1 shows an embodiment of an inventive

Brake system.

In Fig. 1, an embodiment of a brake system according to the invention for a motor vehicle with four hydraulically betä ^¬ tigbaren wheel brakes 8a-8d is shown schematically. According to the example, the wheel brake 8a is assigned to the left front wheel (FL), the wheel brake 8b to the right front wheel (FR), the wheel brake 8c to the left rear wheel (RL) and the wheel brake 8d to the right rear wheel (RR). The wheel brakes 8a, 8b are thus associated with the front axle VA and the wheel brakes 8c, 8d of the rear axle HA. Other assignments of the wheel brakes 8a-8d to the wheels (FL, FR, RL, RR) are conceivable.

The brake system comprises a means of a brake pedal 1 be ^¬ tätigbare simulation means 3, a first electrically controllable pressure supply device 5, a second electrically controllable pressure supply device 2, an under-atmospheric pressure fluid reservoir 4, and individual wheel brake pressure modulation valves which according to the example as an inlet valves 6a-6d and an outlet ^¬ valves 7a-7d per wheel brake 8a-8d are executed. Furthermore, by way of example, an electronic control unit 12 is provided for controlling the electrically actuatable components of the brake system, for supplying power to electrical components of the brake system and / or for evaluating signals from sensors of the brake system or from environmental sensors.

Simulation device 3 has a housing in a simulator piston 31, which is supported by a arranged in a simulator rear chamber 30 elastic member 33 (eg simulator spring) on the housing. A piston rod 24 coupled the pivotal movement of the brake pedal 1 due to a pedal operation with the translational movement of the simulator piston 31, the actuation path is detected by a preferably re ^¬ dundant executed distance sensor 25. Thus, the corresponding Kolbenwegsignal is a measure of the Bremspedalbe ^¬ tätigungswinkel. It represents a braking request of a driver. For the driver request detection, a further sensor 20 is provided which detects an independent of the piston stroke of the simulator piston 31 physical quantity, which characterizes the braking request of the driver. This can be eg a force sensor or a pressure sensor.

The first electrically controllable pressure supply device 5 is designed as a hydraulic cylinder-piston arrangement (or a single-cylinder electro-hydraulic actuator (linear actuator)) whose piston 36 is actuated by a schematically indicated electric motor 35 with the interposition of a rotationally-translational gear 39 likewise shown schematically, in particular can be moved back and forth to build up a pressure in a pressure chamber 37 and. The piston 36 limits the pressure chamber 37 of the Druckbereitstel ^¬ lling device 5. To control the electric motor, a rotor position of the electric motor 35 detected, only sche ^¬ matically indicated rotor position sensor 44 is provided.

To the pressure chamber 37 of the first electrically controllable pressure supply device 5, a system pressure line section 38 is connected. Line section 38 is via an electrically actuated, preferably normally open,

Separating valve 26 connected to a brake supply line 13, via which the input terminals of all intake valves 6a-6d with the pressure chamber 37 of the first electrically controllable

Pressure supply device 5 are connected. Through the isolation valve 26, the hydraulic connection between the Pressure chamber 37 and the first pressure supply device 5 and the brake supply line 13 (and thus the input terminals of the intake valves 6a-6d) controlled open and shut off.

By way of example, in an unactuated state of the piston 36, the pressure chamber 37 is connected to the pressure medium reservoir 4 via one or more sniffer holes and a line 42. This connection between the pressure chamber 37 and the line 42 or the pressure medium reservoir 4 is separated during a (sufficient) actuation of the piston 36 in the direction of pressure build-up (to the right in FIG. 1).

The first pressure supply device 5 is a

high-performance printing plate, in the error-free

Brake system realizes the normal brake function with maximum comfort and maximum dynamics.

The second electrically controllable Druckbereitstellungssein- device 2 is advantageously designed as a piston pump, in ^¬ particular a radial piston pump. It has a suction port 23, which communicates via a hydraulic connection 41 with the pressure fluid reservoir 4, and a pressure port 27. The pressure port 27 of the second pressure supply device 2 is connected to the brake supply line 13, so that the input ports of the intake valves 6a-6d with the Pressure port 27 of the second pressure supply device 2 are connected. Between the pressure port 27 and the brake supply line 13 is, for example in accordance with no valve (for example, another electrically betae ^¬ tigbares separating valve) is arranged.

The radial piston pump 2 is associated with an overflow valve 32, whose activation is a pressure limitation and pressure reduction rea- can lisieren. For this purpose, the pressure port 27 of the second pressure supply device 2 via the overflow valve 32 to the suction port 23 and thus to the pressure medium ^¬ reservoir 4 is connected. The overflow valve 32 is, for example, normally closed and analogously controllable. By means of the overflow valve 32, the pressure provided by the second pressure supply device 2 for the wheel brakes can be limited or reduced. As already mentioned, the brake system comprises per each hydraulically actuable wheel brake 8a-8d an inlet valve 6a-6d and an outlet valve 7a-7d, which are hydraulically interconnected in pairs via center connections and connected to the wheel brake 8a-8d. The inlet valves 6a-6d are each connected in parallel with a brake supply line 13 to the opening, unspecified check valve. The off ^¬ gear connections of the exhaust valves 7a-7d are connected via a ge ^¬ my same return line 14 with the pressure fluid supply reservoir. 4 The input ports of all intake valves 6a-6d can be supplied with pressure by the brake supply line 13, which is provided by the first pressure supply device 5 or, for example, in the event of failure of the first pressure supply device of the second pressure supply device 2.

In the brake supply line 13, an electrically operable, advantageously normally open Kreistrennventil 40 is arranged, through which the brake supply line 13 in a first line section 13 a, which is connected to the second pressure supply device 2, and a second line section 13 b, which (via the isolation valve 26) the first pressure supply device 5 is connected, can be disconnected. In this case, the first line section 13a with two of the intake valves, namely the intake valves 6a and 6b, hydraulically connected and the second line section 13b is hydraulically connected to the remaining inlet valves, namely the inlet valves 6c and 6d. By closing the

Circular valve 40, the brake system is thus hydraulically separated or divided into two (partial) brake circuits I and II. In the first brake circuit I, the second pressure ^{supply device} 2 is connected to only the wheel brakes 8a and 8b, and in the second brake circuit II the first pressure ^{supply device} 5 is connected to only the wheel brakes 8c and 8d.

The brake system comprises per brake circuit I or II, a pressure sensor 19. This is preferably in front of one of the wheel brakes, according to the wheel brakes 8a and 8d, arranged. According to the example, the brake system for leakage monitoring comprises a level measuring device 50 for determining a pressure medium level in the pressure medium reservoir 4.

Also associated with each wheel is, for example, a wheel speed sensor 10a-10d, which may be e.g. for anti-lock control functions (ABS) are required.

The brake system is further connected to a driving dynamics sensor 60 or includes such. The driving dynamics sensor 60 comprises at least one measuring device for detecting one or more of the following variables:

Longitudinal acceleration, in particular Fahrzeuglängsbe ^¬ acceleration

Lateral acceleration, in particular vehicle lateral acceleration

yaw rate

steering angle The first pressure supply device 5 is assigned to the control of a first electronics or first electronic device B. The electronic device B is for example part of the electronic control unit 12, but it can also be designed as a separate unit or elekt ^¬ ronic control unit.

The second pressure supply device 2 is assigned to the control of a second electronics or second electronic device A. The electronic device A is for example part of the electronic control unit 12, but it can also be designed as a separate unit or elekt ^¬ ronic control unit. In this case, the second electronic device A is electrically independent of the first electronic device B.

The first electronic device B is powered by or includes a first electrical energy source. The first pressure supply device 5 is also from the first electrical energy source or

Energy supply supplied with energy. For simplicity, for example, the first pressurizing device 5 is supplied with power (from the first electric power source) via the first electronic device B. The first electrical energy source is e.g. a first electrical system.

The second electronic device A is supplied by or comprises a second electrical energy source or energy supply. The second pressure supply device 2 is likewise supplied by the second electrical energy source or energy supply. For the sake of simplicity, in ^¬ game according to the second pressure supply device 2 via the second electronic device A with energy (from the second electrical energy source). The second electrical energy source is eg a second electrical system.

The second electrical energy source or energy supply is independent of the first energy source or energy supply.

Other components of the brake system are advantageously assigned either to the first electronic device B (which actuates the first pressure supply device 5) or to the second electronic device A (which activates or actuates the second pressure supply device 2). That They are controlled or actuated by this device and / or supplied with electrical energy and / or signal side connected to this device and / or are evaluated by this device. In Fig. 1, those components which are associated with the first electronic device B (ie associated with the so-called partition B) are indicated by an arrow with B, while those components associated with the second electronic device A (ie the so-called partition A are assigned) are indicated by an arrow with A. In order to avoid further redundancies, it is advantageous if a component is only or exclusively controllable by one of the two electronic devices, but not by the other electronic device. operable or supplied with electrical energy or signal connected or evaluable.

The spill valve 3 and the isolation valve 26 are associated with the second electronic device A and are thus controlled by the second electronic device A and / or supplied with electrical energy.

The inlet and outlet valves are also partition A assigned and are controlled by the second electronic device A and / or supplied with electrical energy. However, the circular separator valve 40 is associated with the partition B and is controlled by means of the first electronic device B and / or supplied with electrical energy.

The wheel speed sensors 10a-10d are assigned to the partition A and are supplied with electrical energy by means of the second electronic device A and / or evaluated by the second electronic device A.

The driving dynamics sensor 60 is associated with the partition B and is supplied and / or evaluated by means of the first electronic device B with electrical energy.

The second partition A (second electronic device A and / or second power supply) and the first partition B (first electronic device B and / or first power supply) are electrically independent.

By way of example, the hydraulic components, in particular the components 2, 3, 5, 6a-6d, 7a-7d, 32, 40 and 26, in a common module, i. in a single hydraulic control unit (HCU) arranged. The hydraulic control unit is associated with the electronic control unit (ECU) 12. HCU and ECU are advantageously implemented in a manner known per se as one unit (HECU). It can also be provided two or more electronic control units.

An arrangement in two or more modules or hydraulic control and regulating units (HCU) is also conceivable. Also can Each hydraulic control units (HCU) to be assigned its own electronic control unit (ECU). For example, the simulation device 3 can advantageously be designed in a separate module. Other divisions and further modules are conceivable.

The following are various operating procedures of

Brake system described. If one of the two pressure supply devices 2 or 5 fails due to a fault (for example due to a failure of one of the electrical energy sources), then the respective other pressure supply device 5 or 2 via the brake supply line 13 (with normally open Kreistrenn- valve 40) all wheel brakes 8a-8d actuate.

If the first pressure supply device 5 fails as a result of error, the separating valve 26 is closed by means of the second electronic device A assigned to the second pressure supply device 2, in order to avoid a pressure medium volume loss through the sniffer hole of the failed pressure supply device 5. For this purpose, the second pressure supply device 2 is assigned to the control thereof, in particular the electric motor of the radial piston pump, the second electronic device A, wherein this also the

Isolating valve 26 controls or its valve coil with

supplied electrical energy.

Control strategy for residual brake function after an error: a) Failure of the first pressure supply device 5 The second electronic device A / second energy supply of the second pressure supply device 2 (partition A), in addition to the isolation valve 26, also the wheel associated wheel valves 6a-6d, 7a-7d, ie the wheel control valves 6a-6d, 7a-7d are controlled by the second electronic device A (second partition A) or supplied with electrical energy. Likewise, the wheel speed sensors 10a-10d are associated with the second electronic device A (second partition A), ie their signals are supplied to the second electronic device A and advantageously evaluated by the second electronic device A. The second electronic device A or A partition now leads practically unchanged, as basically known from Antiblo- ckierregelungen and other wheel-individual brake pressure control ^¬ functions and realized along with the ability to build up brake pressure, all residual brake functions. b) failure of the second pressure supply device 2, the first electronic device B / first power supply (Partition B) the first compression Deployment ^¬ device 5, the circuit cut-off valve 40 as well as, for example, are associated with the driving dynamics sensors 60th The pressure-providing device 5 is the high-performance pressure plate, which realizes the normal braking function in the highest degree of comfort and dynamics in the error-free system. The partition B or the first

Pressure supply device 5 regulates the pressure even in case of failure of the pressure supply device 2 still with very high dynamics and accuracy centrally. The controllability of the circular valve 40 by the first electronic device B ^¬ even allows that different pressures can be adjusted by axle. This is done by an axis-multiplexing method. The performance of this control strategy is not at the level of the faultless system in terms of braking performance. However, it is sufficient for the ^{¬ written} error case to ensure the residual braking functions. The exemplary brake system provides the necessary redundancy for the realization of highly automated driving functions to implement autonomous braking requirements. Even after a serious error, such as a failure of the first power supply of the partition B or the first pressure supply device, the brake system is able to continue to implement certain residual braking functions autonomously or controlled by an autopilot. The most important residual brake functions of the brake system are:

Build up delay;

Comply blocking order of the axes and avoid unge ^¬ wolltes destabilizing at higher delays;

Steerability maintained to allow the (car) pilot also braked evasive maneuvers.

Claims

Brake system for a motor vehicle with

• at least four hydraulically actuated wheel brakes

(8a-8d),

A simulation device (3),

An electrically actuated intake valve (6a-6d) per wheel brake (8a-8d) for setting wheel-specific brake pressures,

• a first electrically controllable pressure supply device (5) which is hydraulically connected separably via a separating valve (26) with a brake supply line (13) to which the wheel brakes (8a-8d) are connected via in each case one of the inlet valves, and

A second electrically controllable pressure supply device (2), which is hydraulically connected to the brake supply line (13),

wherein in the brake supply line (13) an electrically operable Kreistrennventil (40) is arranged such that at a closed Kreistrennventil the Bremsversor ^¬ supply line (13) in a first and a second line section (13a, 13b) is hydraulically separated, wherein the first line section ( 13a) is hydraulically connected to two of the inlet ^¬ valves (6a, 6b) and the second line section (13b) with the remaining inlet valves (6c, 6d) is hydraulically connected, and wherein the second

Pressure supply device (2) is hydraulically connected to the first line section (13a) and the first pressure supply device (5) is hydraulically connected via the separating valve (26) to the second line section (13b),

characterized in that

the second pressure supply device (2) a Suction connection (23) and a pressure connection (27), wherein for adjusting or regulating the pressure provided by the second pressure supply device (2) an overflow valve (32) is provided, via which the pressure connection (27) to the suction port (23) hydraulically connected is.

Brake system according to claim 1, characterized in that the overflow valve (32) is designed to be de-energized closed.

Brake system according to claim 1 or 2, characterized in that the simulation device (3) by means of a brake pedal ^¬ (1) is actuated, and that no mechanical and / or hydraulic operative connection between the brake pedal and the wheel brakes is provided.

Brake system according to one of the preceding claims, characterized in that the second Druckbereitstellungsein ^¬ direction (2) by a piston pump, in particular radial piston pump, is formed.

Brake system according to one of the preceding claims, characterized in that the second Druckbereitstellungsein ^¬ direction (2) is connected directly to the first line section (13a) hydraulically.

Brake system according to one of the preceding claims, characterized in that the circular selector valve (40) is designed to be normally open.

Brake system according to one of the preceding claims, characterized in that the separating valve (26) is designed to be normally open. Brake system according to one of the preceding claims, characterized in that the first Druckbereitstellungssein ^¬ direction (5) by a cylinder-piston assembly with a hydraulic pressure chamber (37) is formed, the piston (36) by an electromechanical actuator (35, 39) is actuated, wherein the pressure chamber is connected in an unactuated state of the piston (36) via at least one Schnüffelloch with a line (42) to a pressure medium reservoir (4), said compound is separated upon actuation of the piston (36).

Brake system according to one of the preceding claims, characterized in that it is a first electronic Vor ^¬ direction (B), by means of which the first Druckbereit ^¬ positioning device (5) is controlled, and a second electronic device (A), by means of which the second pressure supply device ( 2), wherein the second electronic device (A) is electrically independent of the first electronic device (B).

Brake system according to claim 9, characterized in that the first electronic device (B) is supplied by a first electrical power supply or comprises a first electrical power supply, and that the second electronic device (A) is supplied by a second electrical power supply or a second electrical Power supply, wherein the first electrical power supply is independent of the second electrical power supply.

Brake system according to claim 9 or 10, characterized in that the overflow valve (3) and the separating valve (26), are driven in particular exclusively, by means of the second elekt ^¬ tronic device (A) and / or supplied with electric power. 12. Brake system according to one of claims 9 to 11, characterized in that the inlet valves, and optionally the exhaust valves, in particular exclusively, by means of the second electronic device (A) are driven and / or supplied with electrical energy.

13. Brake system according to one of claims 9 to 12, characterized in that the Kreistrennventil (40), in particular ^¬ special exclusively, by means of the first electronic device (B) is driven and / or supplied with electrical energy.

14. A method for operating a brake system according to one of claims 1 to 13, characterized in that in case of failure of the first pressure supply device (5) or electronic device (B) or power supply the

Separation valve (26) is closed, by means of the second pressure supply device (2), a pressure build-up is performed and by means of the intake valves (6a-6d), and in particular the exhaust valves (7a-7d), and the spill valve (32) wheel-specific brake pressures to the

Wheel brakes can be adjusted.

15. A method for operating a brake system according to one of claims 1 to 13, in particular according to claim 14, characterized in that in case of failure of the second

Pressure supply device (2) or electronic device (A) or energy supply by means of the first pressure supply device (5), a pressure build-up is performed and by means of the circular valve (40) for the first and the second line section individual brake pressures are set.