DE102018133189A1 - Redundant braking system with 2 pressure supplies for electric vehicles and vehicles with autonomous driving from level 3 (HAD) to level 5 (AD) - Google Patents

Abstract

The invention relates to a brake system for a vehicle, comprising the following components: - at least two hydraulic brake circuits, each with at least one hydraulically acting wheel brake, - at least two pressure supply devices (DV1, DV2), each having a piston-cylinder unit, the pistons of which have a piston Gearboxes, in particular a spindle drive are driven by an electric motor drive, - at least one valve arrangement with valves for setting the wheel-specific brake pressures and / or for separating or connecting the wheel brakes to a pressure supply device - at least one electronic control unit, characterized in that a Pressure supply device has two mutually independent electronic control and regulating units or a double-redundant control and regulating unit for controlling its electromotive drive, and / or each pressure supply device each has a brake circuit for the regulating unit Drive of the brake system is assigned, and that a connection module is provided for the optional connection of the brake circuits, such that if one pressure supply device fails, the pressure supply or pressure control for both brake circuits is carried out by the other still functioning pressure supply device.

Description

designation

The present invention relates to a device for a hydraulic actuation system for a brake for electric vehicles and in particular vehicles with highly automated, fully automated or autonomous driving

State of the art

The automotive industry is in a disruptive change process. In addition to the increasing market penetration of electric vehicles, various stages of automated driving are going through, these are initially: Level 3 - Highly automated driving - HAD, Level 4 - Fully automated driving - FAD and Level 5 - Autonomous driving - AD, with the requirements at each level increase to the brake systems used. This pushed the development of new braking systems. The replacement of vacuum brake boosters with electric brake boosters (e-BKV) began in 2005 after initial solutions [ATZ issue 6/11] with the market launch of so-called 2-box solutions with electric follow-up brake boosters and an additional ESP unit in 2013 [ATZ edition 4/18], followed shortly by the first integrated 1-box systems with pedal simulator in 2017 [Brake Manual - Chapter 20]. Solutions for level 3 (HAD) are currently being developed.

From level 3rd (HAD) a redundant pressure supply is mandatory for the first time. In addition, a connection between the brake circuits and the reservoir with open brake systems should be avoided as far as possible and pedal feel simulators with constant pedal characteristics should be used. Redundancy of the ABS function must also be provided. This is in accordance with the state of the art in so-called 2-box systems with an electric brake booster and ESP / ABS unit DE112009005541B3 Realized in such a way that the electric brake booster (e-BKV) takes over a pressure modulation function in the event of a failure of the ESP unit in order to always ensure a high vehicle deceleration. In the first step, a so-called “ABS select-low control” was introduced.

From level 4th (FAD) triple redundancies are expected for sufficient system availability, for example with the pedal sensors with the rule "2 out of 3". In addition, a pedal simulator is imperative due to the increasing recuperation power of electric vehicles and the lack of acceptance of the change in the pedal characteristics, because fully automatic driving (FAD) can be operated over a longer period of time and the driver is not prepared for a change in the pedal characteristics when switching to piloted driving. A redundant pressure transmitter is to be provided for monitoring the pressure supply or an alternative diagnostic option is to be provided. Furthermore, a redundant ABS function with at least axis-specific control will be required and partial redundancies will be introduced. Brake systems with closed brake circuits in ABS operation have safety advantages.

In stage 5 (AD) pedal travel sensors and pedal simulators and their characteristics are no longer relevant. In contrast, the remaining components and subsystems will have a triple redundancy, with the rule “2 out of 3” for sensors, control and regulating units ECU and partial ECU, or multiple redundancy. In addition, complete redundancy must be provided for the wheel-specific control.

Several new vehicle manufacturers such as Apple, Uber or Waymo are working on completely autonomous vehicles without a driver, which in the first stage have a brake pedal with a simple pedal feel simulator unit (level 4th FAD) and in the last expansion stage (level 5 AD) should no longer have a brake pedal. In addition, vehicles with strong electric drive motors, both on the rear axle and on the front axle, are becoming increasingly popular.

In addition to the electro-hydraulic brake systems described, there is the electromechanical brake ( EMB , electromechanical wedge brake) as a known solution. The EMB has not prevailed in the past due to security concerns and high costs. The high costs are due in particular to the fact that an electric motor and a complex electromechanical mechanism are required for each wheel brake. Also has one EMB very many electrical contact points, which are known to be more prone to errors than hydraulic lines.

Brake systems for levels FAD and AD cannot be used exclusively for reasons of cost and reliability EMB or have wedge brakes. A EMB is only for the rear axle of a vehicle suitable because the rear axle has a smaller share of the braking force and a failure is not considered as critically as on the front axle. A hydraulic brake system with control in the predominantly closed brake circuit via an electrically driven piston-cylinder unit is preferred.

In DE102005055751B4 and DE102005018649B4 The high-precision piston pressure control (PPC = Piston Pressure Control) is carried out by means of an electrically driven piston-cylinder unit with a spindle drive. The pressure is controlled using a non-linear map, the so-called pressure-volume characteristic, in which the relationship between pressure and piston position is evaluated. Alternatively or additionally, the pressure is used by controlling the phase current of the electric motor, the physical relationship between the proportionality between current and torque and, due to a known piston surface and fixed gear ratio, also the proportionality between current and pressure. With these two parameters, the pressure and the pressure change curve can be controlled very precisely.

In EP1874602B1 and EP2396202B1 describes the so-called multiplex process (MUX), which is particularly suitable for the requirements of the stage 4th and 5 Suitable because a closed brake system, as explained later, has no sleeping errors. In addition, several wheel brakes can be built up and down in pressure with only one switching valve at the same time or one after the other. The high dynamic demands on the electric motor are disadvantageous, especially if all wheel brakes are controlled by one motor. This requires a special motor with a double air gap, such as the one from EP 1759447B1 is known or a motor with a very low mass of inertia.

In WO201614622A2 is also a special valve circuit of switching valves, where the interior of the switching valve is connected to the associated brake circuit via a hydraulic line and the valve seat compensation is connected to the associated wheel brake via a hydraulic line. This valve circuit is particularly suitable for the MUX process with only one switching valve per brake circuit, since in the event of a fault the solenoid valve opens due to the pressure in the wheel brake and thus prevents the pressure in the wheel brake from being locked up, which leads to unwanted vehicle deceleration.

Out EP3271221A2 is a further developed MUX process (MUX 2.0 ) with only one outlet valve per brake circuit. This can significantly reduce the dynamic requirements for multiplex operation, because pressure can also be reduced via outlet valves in situations with extremely high pressure change dynamic requirements and the brake system is operated in normal operation in a closed brake circuit. As a result, the dynamic requirements on the electric motor can be significantly reduced or a very good regulation in the multiplex method can be achieved.

Out WO2012059175A1 is an advantageous actuation unit ( BE ) with two displacement sensors and an elastic element acting in between, with which differential paths and / or differential forces are measured and used by the control of the brake system. A brake system with such an actuation unit, supplemented by a pedal feel simulator, requires multiple redundancies of the stage 3rd up to level 5 .

• • Kolben: Kolbendichtungen können ausfallen, wobei die Undichtigkeit z.B. nicht bei kleinen Drücken, sondern erst bei hohem Drücken auftreten können. Eine Undichtigkeit führt zu einem Ausfall der Kolbenfunktion. Kolben werden in Wegsimulatoren, Druckversorgungen und Hauptbremszylindern (HZ) eingesetzt und können zu Pedaldurchfall bzw. Ausfall der Druckversorgung führen.
• • Magnetventile: Schmutzpartikel können sich im Ventilsitz absetzen. Wenn Magnetventile in einem offenen Bremssystem z.B. mit dem Vorratsbehälter verbunden sind, können sich bei Schließvorgang Partikel absetzen und die Verbindung ist nicht dicht. Die Dichtigkeit kann im geöffneten Zustand nicht diagnostiziert werden.
• • Kugel-Gewinde-Trieb: Kugel-Gewinde-Triebe verschleißen über Lebensdauer und können klemmen, insbesondere wenn Schmutzpartikel in den Kugel-Gewinde-Trieb gelangen. Dies kann zu Ausfällen der Druckversorgung führen.

Certain components of brake systems are to be regarded as critical to safety. These are seals for pistons, solenoid valves and ball screws. Various errors and their effects are listed below:

• • Pistons: Piston seals can fail, whereby the leakage cannot occur, for example, at low pressures, but only at high pressures. A leak leads to a failure of the piston function. Pistons are used in displacement simulators, pressure supplies and master brake cylinders (HZ) and can lead to pedal failure or failure of the pressure supply.
• • Solenoid valves: dirt particles can settle in the valve seat. If solenoid valves in an open brake system are connected to the reservoir, for example, particles can settle during the closing process and the connection is not tight. The tightness cannot be diagnosed when open.
• • Ball screw drive: Ball screw drives wear over their service life and can jam, especially if dirt particles get into the ball screw drive. This can lead to pressure supply failures.

• - absolut geräuschloser Betrieb, d.h. keine störenden Geräusche von Aggregaten an der Spritzwand;
• - noch kürzere Bauweise als bei konventionellen PKWs aufgrund neuer Fahrzeug-Plattformkonzepten bei E-Fahrzeugen;
• - Radindividueller oder achsindividueller Bremseingriff, auch bei Komplett- oder Teilausfall von Modulen;
• - Funktionsumfang ABS, ESP, ASR, Rekuperation und Torque Vectoring mit möglichst geringer Einschränkung der Leistungsfähigkeit auch bei Komplett- oder Teilausfall von Modulen;
• - Maximale Rekuperation der kinetischen Energie des Fahrzeuges durch maximale Ausnutzung der Bremsleistung durch Elektromotoren; daher dynamische und genaue bedarfsgerechte Steuerung des hydraulischen Bremssystems;
• - Nutzung von verfügbaren Bremsmomenten, z.B. von Antriebsmotoren für Vereinfachung der Bremssysteme bzw. Verkürzung des Bremsweges;
• - Verstärkte Sicherheit durch Redundanz der Systeme, Signalübertragungen und Stromversorgung;
• - Diagnoseverfahren zur Erkennung von Leckagen bzw. Vermeidung schlafender Fehler;
• - hohe Anforderungen an die Regelgenauigkeit zur weiteren Bremswegverkürzung, insbesondere beim gemeinsamen Wirken von elektrischen Antriebsmotoren und hydraulischen Bremsmomenten;
• - hohe Modularität der Systeme, d.h. der Verwendung von gleichen Teilen/Modulen, insbesondere bei der Druckversorgung; Modularität ist getrieben durch eine Vielzahl an Fahrzeugantriebskonzepten, insbesondere in einer Koexistenz von Fahrzeugen mit Verbrennungsmotoren, Hybridfahrzeugen und reinen E-Fahrzeugen (Verbrennungsmotoren, Hybridmotoren, reine E-Fahrzeuge, fahrerlose Fahrzeuge).

The requirements for level braking systems 3rd (HAD), level 4th (FAD) and level 5 (AD) and for electric vehicles that have increasingly powerful electric drive motors on one or more axles can be summarized as follows:

• - absolutely noiseless operation, ie no disturbing noises from units on the bulkhead;
• - Even shorter design than conventional cars due to new vehicle platform concepts for electric vehicles;
• - Wheel-specific or axle-specific brake intervention, even in the event of complete or partial failure of modules;
• - Range of functions ABS, ESP, ASR, recuperation and torque vectoring with the least possible restriction of performance even in the event of complete or partial failure of modules;
• - Maximum recuperation of the kinetic energy of the vehicle through maximum utilization of the braking power by electric motors; therefore dynamic and precise needs-based control of the hydraulic brake system;
• - Use of available braking torques, for example drive motors, to simplify the braking systems or shorten the braking distance;
• - Increased security through redundancy of the systems, signal transmissions and power supply;
• - Diagnostic procedures for the detection of leaks or avoidance of sleeping errors;
• - high demands on the control accuracy to further shorten the braking distance, especially when electric drive motors and hydraulic braking torques work together;
• - High modularity of the systems, ie the use of the same parts / modules, especially in the pressure supply; Modularity is driven by a variety of vehicle drive concepts, especially in the coexistence of vehicles with internal combustion engines, hybrid vehicles and pure e-vehicles (internal combustion engines, hybrid motors, pure e-vehicles, driverless vehicles).

Object of the invention

The object of the present invention is to provide a braking system which meets the requirements of high availability in fully automated driving (FAD) and autonomous driving (AD) and is also suitable for electric vehicles.

Solution of the task

The object of the invention is achieved by a braking system with the features of claim 1. Advantageous embodiments of the brake system according to claim 1 result from the features of the subclaims.

The invention is advantageously characterized in that redundancy requirements of fully automated driving (FAD) and autonomous driving (AD) are met and, at the same time, high synergy effects are used in the interaction of the braking system with electric drive motors of electric vehicles. For example, the energy recovery of kinetic energy by the electric motor is not in accordance with the braking system, as is the case with follow-up brake boosters without a travel simulator DE 11 2009 005 541 B3 , restricted. The brake system according to the invention is advantageous for FAD with an actuation unit ( BE ) equipped with pedal feel simulator. However, it is also possible to use the brake system according to the invention for AD without an actuation unit ( BE ) to be carried out, the control of the braking system then taking place via a higher-level control.

In the embodiment for the stage 4th (FAD), an actuation unit with corresponding redundancies must be provided for autonomous driving. The actuation unit optionally has a hydraulic connection to at least one brake circuit or is used as a pure pedal feel simulator without connection to the hydraulics of the brake system, the actuation force then being transmitted purely electrically. An electric brake pedal (E-brake pedal) can be hydraulic or electromechanical.

In the embodiment for autonomous driving (AD), no actuation unit is provided, a central regulating and control unit ( M-ECU ) communicates with the control units.

• - mindestens eine Druckversorgungseinrichtung zwei voneinander unabhängige elektronische Steuer- und Regeleinheiten oder eine zweifach-redundante Steuer- und Regeleinheit zur Ansteuerung ihres elektromotorischen Antriebs aufweist, und/oder
• - jede Druckversorgungseinrichtung jeweils einem Bremskreis für den Regelbetrieb des Bremssystems zugeordnet ist, und dass ein Verbindungsmodul zur wahlweisen Verbindung der Bremskreise vorgesehen ist, derart, dass bei Ausfall einer Druckversorgungseinrichtung die Druckversorgung bzw. Druckregelung für beide Bremskreise durch die andere noch funktionsfähige Druckversorgungseinrichtung erfolgt.

For the wheel-specific redundant brake control, the invention provides in a basic embodiment that either

• - At least one pressure supply device has two independent electronic control and regulating units or a double-redundant control and regulating unit for controlling its electromotive drive, and / or
• - Each pressure supply device is assigned to a brake circuit for the control operation of the brake system, and that a connection module is provided for the optional connection of the brake circuits, such that if one pressure supply device fails, the pressure supply or pressure control for both brake circuits is provided by the other, still functional, pressure supply device.

This training provides double redundancy, at least for the pressure supply and its control.

In a further embodiment of the basic embodiment according to the invention for providing further redundancy, it is provided that at least one, in particular each, electronic control and regulating unit controls separate windings of the or an electromotive drive. This advantageously ensures that if a winding system fails, the drive motor can still be operated at least half the maximum torque.

The previously described embodiments can also be made safer if each pressure supply device is advantageously assigned one, in particular redundant, valve arrangement or two pressure supply devices, a redundant valve arrangement. The invention understands a redundant valve arrangement in such a way that if one or both control and regulating units of the pressure supply device fail, the solenoid valves of the pressure supply can still be operated safely.

In a further embodiment, the pressure supply device, together with the valve arrangement and the at least one electronic control and regulating unit assigned to the pressure supply device, can be combined to form a module or assembly. This results in a compact and inexpensive unit that can be accommodated and installed in the vehicle in a space-saving and simple manner.

If an actuating device is provided, in particular in the form of a brake pedal, it is advantageous if it acts on a piston-cylinder unit and adjusts its piston so that, in the event of a fault, a hydraulic pressure can be used to build up brake pressure with the actuating device in at least one brake circuit . A simple master brake cylinder or a tandem master cylinder, optionally with redundant seals, and an absolutely necessary displacement simulator can be provided.

The above-described brake systems advantageously regulate in closed-loop operation, i.e. in normal operation there is no pressure reduction via solenoid valves in the storage container, and / or the pressure in the wheel brakes of the respective brake circuit is multiplexed and / or adjusted or set simultaneously. For safety, the switching valves should be connected to the wheel brakes in such a way that they open automatically due to pressure in the wheel brakes. This advantageously ensures that the brake pressure in the wheel brakes can be reduced in any case and that there is no undesired braking or locking of the wheels.

It is also advantageous if, in the case of the brake systems described above, a pressure reduction in normal operation, in particular in the case of very high pressure dynamic requirements, e.g. in the case of high-µ ABS control, in particular in the event of failure of a pressure supply device and / or a control and regulating device for a pressure supply in a wheel brake, by opening an outlet valve in the reservoir, in particular in the expanded multiplex mode (so-called MUX 2.0 method) a pressure supply device for all wheel brakes takes over the pressure control.

In a further very advantageous embodiment of the brake systems described above, at least one wheel brake, preferably two wheel brakes, is a hydraulically assisted electromechanical brake ( H-EMB ), an electric parking brake (EPB) or an electromechanical brake ( EMB ). At the same time, in addition to a conventional hydraulic wheel brake, an electric motor, an additional electric parking brake or an electromechanical brake can have a braking effect on the wheel. By this measure further redundancy is created. If a hydraulically assisted electromechanical brake is provided, it can advantageously be used to build up a braking force both hydraulically and electromechanically.

If no actuation device and / or a traction motor for a wheel or an axle is provided in one of the brake systems, the brake system, in particular also the electronic control and regulating units of the pressure supply devices, should be controlled by a superordinate central control unit. The higher-level control unit can be the pressure supply devices, valves, electric drive motors and / or EMB or. H-EMB control during the braking process and / or ABS control mode and / or to diagnose the braking system and can also control other driving dynamics functions (eg steering, damping, roll stabilization) in a sensible manner in addition to the brake.

If at least one electric drive or traction motor is provided for at least one axle or wheel of the vehicle, it can advantageously be used for braking an axle or a wheel. This provides further redundancy. In normal operation or in the event of failure of a component of the brake system, for example a pressure supply device, a (supporting) braking force can also be generated by means of the traction motor (s). Through a combined use of pressure supply devices, hydraulically assisted electromechanical brake (s) H-EMB , electric parking brake (s) EPB and / or electromechanical brake (s) EMB and / or one or more drive motor (s) can advantageously during normal operation or in the event of failure of one or more components of the braking system, a faster increase in braking force with a shorter time to lock ( TTL ) occur or a higher braking torque is generated.

Advantageously, in the brake systems described above, each pressure supply device can be preceded by at least one isolating valve at the outlet of the pressure supply, the respective pressure supply device being able to be disconnected from the respective brake circuit by closing the isolating valve, in particular if it fails.

In order to make the braking system according to the invention even safer against failure, at least one control and regulating device of a pressure supply and valve arrangement can have a separate voltage supply and in particular signal transmission, in particular all modules of a pressure supply device, can be supplied by at least two on-board networks and / or can have redundant signal transmissions. In the context of the invention, two on-board networks mean that either different voltage levels and / or voltage sources serve to supply the braking system.

It is also advantageous if, in the aforementioned possible embodiments of the brake system according to the invention, either the pressure control in a brake circuit using at least one pressure sensor and / or via the current measurement of the motor current of the drive and displacement control of the piston of the pressure supply device, which takes place by taking into account the temperature of the Drive can be further refined in the pressure control quality. This enables precise pressure control even without a pressure sensor, as already described in DE102005055751B4 of the applicant in function without a temperature sensor is explained in detail.

In the event of an error, e.g. In the event of valve leakage, to enable safe separation of the brake circuits and to reduce pressure in the wheel brakes, it is advantageous if a connection module with switching valves is arranged between the brake circuits, so that either the brake circuits can be connected to one another, separated from one another and / or one or both brake circuits can be connected to the storage container, in particular if no actuating device is provided via which pressure can be reduced in the storage container. Solenoid valves which are normally open are advantageously used to connect the brake circuits to the reservoir. For the connection between the pressure units, normally closed solenoid valves or hydraulic fluid transmission pistons that can be locked in position are to be used in the connection module.

The connection module can either z. B. have several solenoid valves, via which a hydraulic connection between a brake circuit and the reservoir or between the two brake circuits can be established. However, it is also possible for the connection module to be formed by a piston-cylinder unit, the piston of which separates a first and a second pressure chamber from one another, the first pressure chamber being connected to the first brake circuit and the second pressure chamber being connected to the other second brake circuit and the piston can be locked by means of a blocking device. In the locked Condition would then be virtually no hydraulic connection between the brake circuits, since a volume shift is prevented.

It is also advantageous if the piston-cylinder units of the brake system have redundant seals and hydraulic diagnostic lines and redundant regulating and control units are also provided, and that the drives of the pressure supply devices have 2x3 phases, and that the motor phase current by means of sensors i _phase , the engine angle a, in particular the temperature T, is measured and taken into account in the pressure control, and that there is a redundant supply via two on-board networks or voltage levels, and that redundant signal transmission is provided. The provision of all these measures advantageously results in a very secure system, which is used for the AD stages 3-5 suitable is.

Advantageously, a reservoir can be used in the brake systems described above, which has a plurality of separate chambers, one chamber of the reservoir being hydraulically connected or connectable to at least one pressure supply device and / or a further chamber being hydraulically connected or connectable to the connection module. This advantageously results in further switching options by means of the valves used, which contribute to the further safety of the braking system.

The brake systems described above can advantageously be operated in such a way that at least axially, preferably individually, the deceleration of the wheels by means of the pressure supply device (s), the electric drive motor (s) and the hydraulically assisted electromechanical brake ( H-EMB ) or the electromechanical brake ( EMB ), he follows. Torque vectoring can also be carried out by means of the pressure supply device (s), the electric drive motor (s) ( TM ) and the hydraulically assisted electromechanical brake ( H-EMB ) or the electromechanical brake ( EMB ).

When using a temperature sensor, the temperature of the drive of the pressure supply device (s) can also be determined and the temperature can be used for more precise determination of the torque moment constant, which linearly decreases by the factor (1-Br% * ΔT) due to the temperature rise. An even more precise regulation of the torque and thus of the pressure can thus be carried out, provided this is based on the phase current i, since the relationship torque = kt (T) * phase current i applies.

In addition to the current control, the piston position and the pressure volume characteristic curve and the change in the pressure volume characteristic curve, for example with air inclusion, by the pressure sensor or the H-EMB be adjusted. The combined use of the two methods described above results in highly precise pressure control, which is also possible without a pressure sensor. This method provides additional redundancy in the event of pressure transmitter failure or can also be used to simplify the system with low redundancy requirements (eg system with only one or without pressure transmitter).

The brake system according to the invention can also be used for steering / torque vectors, the wheel-specific control options with the at least one pressure supply and the hydraulically supported electromechanical brake (s) H-EMB , electric parking brake (s) EPB and / or electromechanical brake (s) EMB and / or drive motors or the steering EPS can be used.

• - vornehmlicher Betrieb im geschlossen Bremskreis (>90% der Betriebszeit) sowohl im Bremskraftverstärker (e-BKV), Rekuperationsbetrieb als auch vorwiegend im ABS-Regelbetrieb, damit werden schlafende Fehler vermieden. Wird das System offen betrieben, z.B. ist im ABS durch Öffnung eines Auslassventils der Radkreise mit dem Vorratsbehälter hydraulisch verbunden, sind unerkannte Undichtigkeiten bei Ventilen und Dichtungen (schlafende Fehler) besonders schwer zu erkennen. Daher ist der Betriebszustand zu vermeiden bzw. eine Diagnose der Dichtigkeit nach jedem ABS-Betrieb sinnvoll; eine Diagnose kann derart erfolgen, dass z.B. im Stillstand der Kolben der Druckversorgung bei geschlossenen Ventilen bewegt wird und ein Volumenverlust oder Druckanstieg ermittelt und ausgewertet wird.
• - Redundanzen und Teilredundanzen der DV-Motorelektronik: z.B. Ausführung des Motors der DV als 2 x 3 Phasenmotor sowie Teilredundanz der Motoransteuerung. Damit kann bei Ausfall einer Teilelektronik (Wicklungskurzschluss, Ausfall eines 3-Phasenstranges) der Motor noch mit halbem Drehmoment betrieben werden. Bei einer Auslegung auf 200 bar kann dann auch bei Ausfall noch 100 bar, d.h. näherungsweise der Blockierdruck erreicht werden. Damit ist auch bei Ausfall einer Elektronik noch ein ABS-Betrieb mit maximaler Leistung bei Niedrigreibwerten und zufriedenstellender Leistung bei Straßenzuständen mit hohen Reibwert möglich;
• - Teilredundanzen der Elektronik für die Ventilansteuerung. Fällt die Elektronik aus, ist es für die Verfügbarkeit sehr vorteilhaft, wenn die Schaltventile noch betätigt werden können. Somit ist in der Elektronik eine Redundanz für die Ventilansteuerung vorzusehen, damit die Ventilbetätigung bei Ausfall der Motorsteuerung noch funktioniert;
• - Betrieb im geschlossenen MUX-Betrieb mit Schaltventilen und Einsatz von Auslassventilen (mindestens 1 AV je Achse) im Fehlerfall, d.h. Ausfall oder Teilausfall einer Druckversorgung. Damit kann mit geringer Motorleistung die Druckregeldynamik noch aufrechterhalten werden, da der Druck nicht nur durch die Druckversorgung sequentiell oder simultan auf- und abgebaut werden kann, sondern auch ein Druckabbau über Auslassventile erfolgen kann;
• - Einsatz einer H-EMB, EMB oder EPB im Bremsbetrieb, insbesondere Einsatz EPB oder H-EMB beim Ausfall von Modulen. Damit kann zum einen eine Radbremsung über den hydraulischen Zugang sowie über den in der H-EMB verbauten Elektromotor erfolgen. Der Elektromotor kann als EC-Motor oder Bürstenmotor ausgeführt werden. Somit kann eine Bremskraftunterstützung durch den Elektromotor am jeweiligen Rad erfolgen;
• - Nutzung der eingesetzten Traktionsmotoren zur Steigerung des Bremsmomentes bei gleichzeitiger Rekuperation von kinetischer Fahrzeugenergie. Aufgrund der hohen Trägheitsmassen des Antriebsmotor ist jedoch zu berücksichtigen, dass ein Bremsmoment über den Traktionsmotor weniger dynamisch aufgebaut werden kann, als über die Druckversorgung und die H-EMB, EPB oder EMB;
• - Einsatz einer fehlersicheren und diagnosefähigen Betätigungseinheit mit Pedalgefühlsimulator, redundanten Wegsensoren und einem Kraft-WegSensor (KWS) sowie einer speziellen Schaltung zur Diagnose des Pedalgefühlsimulators;
• - Einsatz von Ventilen mit Selbstöffnungsmechanismus durch Druckbeaufschlagung durch die in Radbremse insbesondere im stromlosen Zustand;
• - Einsatz eines diagnosefähigen Verbindungsmoduls (VM) mit dem die Bremskreise sicher verbunden oder getrennt werden können und eine Verbindung der Radbremsen zum Vorratsbehälter hergestellt werden kann, insbesondere wenn das System keine Betätigungseinrichtung (BE) mit Verbindung zum Vorratsbehälter aufweist;
• - Nutzung einer hydraulischen Rückfallebene in einem Bremskreis bzw. einer Achse über Verbindung der Betätigungseinheit über ein Schaltventil FV;
• - Nachfördern von Volumen der DV bei Erreichen der Volumengrenze;
• - Betrieb der Druckstellung ohne Druckgeber durch intelligente genaue Drehmomentschätzung aus dem Motorphasenstrom unter Einbeziehung der Motortemperatur und der Druckvolumenkennlinie, die über einen Druckgeber oder die H-EMB-Funktion abgeglichen wird;
• - Umschalten von Normalbetrieb 2 Radbetrieb im MUX-Verfahren auf 4-Radbetrieb im MUX 2.0 Verfahren mit AV bei Ausfall einer DV
• - Einsatz von Trapezspindel (kein Blockieren der Spindel durch Schmutzpartikel in der Laufbahn des Kugel-Gewinde-Triebes);
• - Selbsthemmende Trapezspindel -> Verzicht auf FV und TV.

The invention is thus characterized by a very simple structure with very high availability, ie in the event of complete or partial failure of modules, the function is not restricted or is restricted to a very small extent. Even if various components fail, approx. Max. Deceleration and driving stability are ensured. For this purpose, a delay of 0.6 to 0.9 g and an axle-by-axle control, preferably wheel-specific control with steering intervention / stability intervention, are ensured even if a pressure supply device fails. A high level of availability and performance is thus achieved, again in summary, by the following measures, which can be provided individually or in combination:

• - Mainly operation in the closed brake circuit (> 90% of the operating time) both in the brake booster (e-BKV), recuperation mode and predominantly in ABS control mode, thus avoiding sleeping errors. If the system is operated openly, for example, in ABS, the wheel circuits are hydraulically connected to the reservoir by opening an outlet valve, undetected leaks in valves and seals (sleeping errors) are particularly difficult to detect. Therefore, the operating state should be avoided or a diagnosis of the tightness after each ABS operation is advisable; a diagnosis can in such a way that, for example, the piston of the pressure supply is moved when the valves are closed and a loss of volume or pressure increase is determined and evaluated.
• - Redundancies and partial redundancies of the DV motor electronics: eg execution of the motor of the DV as a 2 x 3 phase motor and partial redundancy of the motor control. In the event of failure of one of the electronics (winding short circuit, failure of a 3-phase phase), the motor can still be operated at half the torque. With a design for 200 bar, 100 bar, ie approximately the blocking pressure, can still be reached even in the event of a failure. This means that even if one of the electronics fails, ABS operation is still possible with maximum performance at low friction coefficients and satisfactory performance in road conditions with a high coefficient of friction;
• - Partial redundancies of the electronics for valve control. If the electronics fail, it is very advantageous for availability if the switching valves can still be operated. A redundancy for the valve control is therefore to be provided in the electronics so that the valve actuation still works if the motor control fails;
• - Operation in closed MUX mode with switching valves and use of exhaust valves (at least 1 AV per axis) in the event of a fault, ie failure or partial failure of a pressure supply. This means that the pressure control dynamics can still be maintained with low engine power, since the pressure can not only be built up and reduced sequentially or simultaneously through the pressure supply, but pressure can also be reduced via outlet valves;
• - Use one H-EMB , EMB or EPB in braking mode, in particular use EPB or H-EMB in the event of module failure. On the one hand, this enables wheel braking via the hydraulic access and via the in the H-EMB installed electric motor. The electric motor can be designed as an EC motor or a brush motor. This means that the electric motor can assist the braking force on the respective wheel;
• - Use of the traction motors used to increase the braking torque while at the same time recuperating kinetic vehicle energy. Due to the high inertial mass of the drive motor, it must be taken into account that braking torque can be built up less dynamically via the traction motor than via the pressure supply and the H-EMB , EPB or EMB ;
• - Use of a fail-safe and diagnosable actuation unit with pedal feeling simulator, redundant displacement sensors and a force-displacement sensor (KWS) as well as a special circuit for diagnosis of the pedal feeling simulator;
• - Use of valves with self-opening mechanism by pressurization by the in wheel brake, especially in the de-energized state;
• - Use of a diagnosis-capable connection module ( VM ) with which the brake circuits can be securely connected or disconnected and a connection of the wheel brakes to the reservoir can be established, especially if the system does not have an actuating device ( BE ) with connection to the storage container;
• - Use of a hydraulic fallback level in a brake circuit or an axis by connecting the actuating unit via a switching valve FV;
• - Replenishment of the volume DV when the volume limit is reached;
• - Operation of the pressure position without pressure sensor through intelligent, precise torque estimation from the motor phase current, taking into account the motor temperature and the pressure volume characteristic curve, which is adjusted via a pressure sensor or the H-EMB function;
• - Switch from normal operation 2nd Wheel operation in the MUX process to 4-wheel operation in the MUX 2.0 Procedure with AV if one fails DV
• - Use of trapezoidal spindle (no blocking of the spindle by dirt particles in the track of the ball screw drive);
• - Self-locking trapezoidal spindle -> no FV and TV .

In the tables below, the operating strategies of embodiment 1 ( 2nd Pressure supplies without connection module, 1 ) and embodiments 2nd and 3rd ( 2nd Pressure supplies with connection module, 2nd and 3rd ) described. Table 1: Operating strategy in the event of failures in embodiment 1 (FIG. 1, FIG. 1a, FIG. 1b) Operating status Pressure supply and control valves AV for pressure reduction Actuating ( BE ) Drive motor vehicle ( TM ) H-EMB / EPB EPS (steering) Normal condition MUX operation in the predominantly closed brake circuit with max. Torque for max. Pressure (e.g. 140-200 bar) use AV in special situation high-m ABS (pressure reduction via AV ), ie the brake circuit is opened very rarely and is closed 90-99% of the time Pedal feel unchanged Max. Recuperation of kinetic energy (pressure curve of the DV is ideally matched to the torque and braking power of the TM depending on the required braking power) Is only used for parking at standstill F1: Failure 1x 3 phases of DV2 or DV1 MUX operation with half torque. Pressure eg 70-100 bar to approximately wheel locking pressure commitment AV to improve the control dynamics of MUX operation (pressure reduction via AV ) Pedal feeling unchanged • Optional support in braking torque increase • Intervention in wheel-specific regulation (stabilization / steering) if necessary F2_failure DV1 ( VA ) No function on VA , Disconnect pressure supply DV via isolation valves TV No function Pressure build-up on the front axle through actuation unit (0.4 - 0.6g) • Support for higher delays up to 0.9 g VA , Partial delay on HA • Optional support in braking torque increase • Intervention in wheel-specific regulation (stabilization / steering) if necessary • Axis control F3: failure DV2 ( HA ) No function on HA Pedal feel unchanged • Bremen about TM • H-EMB takes on wheel-specific regulation / deceleration HA F4: _ Complete failure DV1 and D2 No regulation Pressure build-up on the front axle through actuation unit (0.4 - 0.6g) Support for higher delays up to 0.9 g VA , Partial deceleration on HA • delay HA by motor the H-EMB • commitment H-EMB and EPS for stability (steering / torque vectoring) Table 2; Operating strategy in the event of failures in embodiment 2 and 3 (FIG. 2, FIG. 3, FIGS. 3a to 3e) Operating status Pressure supply and control valves AV for pressure reduction Operating status VM Drive motor vehicle ( TM ) H-EMB / EPB EPS (steering) normal MUX operation in the predominantly closed brake circuit with max. Torque for max. Pressure (e.g. 160-200 bar) use AV in special situation high-m ABS (pressure reduction via AV ), ie the brake circuit is opened very rarely and is closed 90-99% of the time closed Max. Recuperation of kinetic energy (pressure curve of the DV is ideally matched to the torque and braking power of the TM depending on the required braking power) Is preferably used only for parking at standstill F1: failure 1x3 phases of DV2 or DV1 MUX operation up to half torque / pressure (e.g. 100 bar) on the respective axis commitment AV to improve the control dynamics of MUX operation (pressure reduction via AV ) closed • Optional support in increasing braking torque • Intervention in radind if necessary. Regulation (stabilization / steering) F2 _ Failure DV1 ( VA ) • No function on VA , Split off DV over TV Active DV takes over the wheel-specific regulation. commitment AV for control for dynamic situations (rapid pressure reduction at high µ). about 10-20% of the time Connection of the brake circuits via VM • Front axle deceleration VA • H-EMB / EPB support in braking torque increase • DV2 takes over control of the 4-wheels in MUX mode AV • H-EMB / EPB; Intervention in individual wheel regulation (stabilization / steering) if necessary F3: failure DV2 ( HA ) • No function on HA , Split off DV over TV Connection of the brake circuits via VM • Deceleration rear axle HA • EPS performs driving dynamics function on the front axle • Bypass: DV1 takes over control of the 4-wheels in the MUX-Betneb AV F4: _ Complete failure DV1 and D2 No regulation • Emergency delay over TM • Emergency delay / stabilization via EPB, H-EMB / EPS

Table 3 shows the pressure supply for the brakes and various driving dynamics control functions (electric brake booster e-BKV, ABS operation, steering / torque vectoring, stability control / ESP, recuperation and parking brake) DV1 and DV2 , Drive motor TM1 , TM2 , Steering EPS and hydraulic assisted EMB or EPB parking brake can be mapped. The primary function and the secondary function / redundancy are identified. This makes it clear that the most important driving dynamics functions are available with at least double redundancy. When configured as a 2x3 phase motor and connection module, the pressure control can even be viewed as 3-fold redundant.

The braking system according to the invention is therefore suitable for all levels of autonomous driving up to level 5 (AD).

The braking system can also be simplified in such a way that a very cost-effective system with lower redundancy requirements and a sensible combination of the primary supply device with the braking units, for example for BRIC countries such as India, Brazil, China, is derived from the system. The redundancy of the pressure supply device with redundant ECU, for example 2x3 phases, is dispensed with here, and the hydraulic fallback level via pressure generation by the driver via the actuation unit and a delay by the electric motor TM utilized. This means that even with a simple actuation unit with a piston (HZ), the current legal regulations for braking deceleration up to 0.3-0.5g for autonomous driving of the steps 1 to 2nd reachable. In addition, for example, the pressure transmitter can be dispensed with and regulated exclusively according to the PPC process. So that the error cases F1 and F3 no longer occur. An electric parking brake can also be omitted if a hydraulically assisted brake H-EMB is used, or a hydraulically assisted parking brake according to DE 10 2007 015809 is used and the pressure in the parking brake is locked in with a solenoid valve. If the hydraulic line fails or there is a leak, it can then be refilled or a holding torque can be generated via the traction motor.

Possible embodiments of the brake system according to the invention are explained in more detail below with reference to drawings.

• 1: Eine schematische Darstellung einer ersten Ausführungsform des erfinderischen Bremssystems mit zwei Druckversorgungseinrichtungen, Magnetventilen, Regel- und Steuereinrichtungen in zwei Druckregelmodul-Baueinheiten, wobei jede Baueinheit mit 2 Radbremsen verbunden ist und einer Betätigungseinheit (BE), die eine hydraulische Verbindung zu einer Druckregelmodul-Baueinheit aufweist;
• 1a: Prinzipschaltbild einer ersten möglichen Ausgestaltung des Bremssystems gemäß 1 mit elektrischer Parkbremse EPB;
• 1b: Prinzipschaltbild einer zweiten möglichen Ausgestaltung des Bremssystems gemäß 1 mit hydraulisch unterstützter elektromechanischer Bremse H-EMB;
• 2: eine schematische Darstellung einer zweiten möglichen Ausführungsform des erfinderischen Bremssystems mit zwei Druckversorgungseinrichtungen, Magnetventilen, Regel- und Steuereinrichtungen in einer Druckregelmodul-Baueinheit, wobei jede Druckversorgung mit 2 Radbremsen verbunden ist und einer Betätigungseinheit (BE), die eine elektrische Verbindung mit der Druckregelungsmodul aufweist, wobei die Bremskreise über ein Verbindungsmodul miteinander verbindbar oder trennbar oder mit dem Vorratsbehälter verbindbar sind ;
• 3: Eine schematische Darstellung einer dritten Ausführungsform des erfinderischen Bremssystems mit zwei Druckversorgungseinrichtungen, Magnetventilen, Regel- und Steuereinrichtungen in zwei Druckregelmodul-Baueinheiten, wobei jede Baueinheit mit 2 Radbremsen verbunden ist und beide Bremskreise über ein Verbindungsmodul miteinander verbindbar oder trennbar oder mit dem Vorratsbehälter verbindbar sind;
• 3a: Prinzipschaltbild einer ersten möglichen Ausgestaltung des Bremssystems gemäß 2 oder 3;
• 3b: Prinzipschaltbild einer zweiten möglichen Ausgestaltung des Bremssystems gemäß 2 oder 3;
• 3c: Druckregelung bei einem Bremssystem gemäß 3a bei Ausfall einer Dreiphasenwicklung eines Antriebsmotors einer Druckversorgungseinrichtung;
• 3d: Druckregelung bei einem Bremssystem gemäß 3a bei Ausfall einer Druckversorgungseinrichtung;
• 3e: Nachfördern aus dem Vorratsbehälter in eine Druckversorgungseinrichtung;
• 4a: Querschnittsdarstellung durch eine hydraulisch unterstützte elektromechanische Bremse;
• 4b: Prinzipschaltbild möglicher Ventilschaltungen und deren Funktion zum Druckabbau in einer Radbremse;
• 4c: Betätigungseinrichtung (BE) mit zugehöriger Kolben-Zylinder-Einheit mit hydraulischer Verbindungsleitung zu einem Bremskreis;
• 5: Druckversorgungseinrichtung mit zwei Steuer- und Regeleinrichtungen;
• 6a: Momentendiagramme zur Darstellung der Bremskraftunterstützung mittels hydraulisch unterstützter elektromechanischer Bremse und Traktionsmotor;
• 6b: Momentendiagramme zur Darstellung der Downsizing-Möglichkeit der Druckversorgungseinrichtung, sofern eine Bremskraftunterstützung mittels hydraulisch unterstützter elektromechanischer Bremse und Traktionsmotor erfolgt;
• 6c: Momentendiagramme zur Darstellung der Bremskraftunterstützung mittels hydraulisch unterstützter elektromechanischer Bremse und Traktionsmotor im Notbetrieb bei Ausfall von Komponenten des Bremssystems;
• 6d: Momentendiagramme zur Darstellung des Bremsmomentenverlaufs während des Nachforderns von Bremsfluid mit der Bremskraftunterstützung mittels hydraulisch unterstützter elektromechanischer Bremse und Traktionsmotor;
• 6e: Bremsdruckregelung bei Ausfall des Druckgebers mittels Strom- und Temperaturmessung und Auswertung der Druck-Volumen-Kennlinie.

Show it:

• 1 : A schematic representation of a first embodiment of the inventive brake system with two pressure supply devices, solenoid valves, regulating and control devices in two pressure control module units, each unit with 2nd Wheel brakes is connected and an actuating unit ( BE ), which has a hydraulic connection to a pressure control module assembly;
• 1a : Basic circuit diagram of a first possible embodiment of the brake system according to 1 with EPB electric parking brake;
• 1b : Basic circuit diagram of a second possible embodiment of the brake system according to 1 with hydraulically assisted electromechanical brake H-EMB ;
• 2nd : A schematic representation of a second possible embodiment of the inventive brake system with two pressure supply devices, solenoid valves, regulating and control devices in a pressure control module assembly, each pressure supply with 2nd Wheel brakes is connected and an actuating unit ( BE ), which has an electrical connection to the pressure control module, the brake circuits being connectable or disconnectable or connectable to the reservoir via a connection module;
• 3rd : A schematic representation of a third embodiment of the inventive brake system with two pressure supply devices, solenoid valves, regulating and control devices in two pressure control module units, each unit being connected to 2 wheel brakes and both brake circuits being connectable or separable with one another via a connection module or being connectable to the reservoir ;
• 3a : Basic circuit diagram of a first possible embodiment of the brake system according to 2nd or 3rd ;
• 3b : Basic circuit diagram of a second possible embodiment of the brake system according to 2nd or 3rd ;
• 3c : Pressure control in a brake system according to 3a in the event of failure of a three-phase winding of a drive motor of a pressure supply device;
• 3d : Pressure control in a brake system according to 3a in the event of failure of a pressure supply device;
• 3e : Re-conveying from the reservoir into a pressure supply device;
• 4a : Cross-sectional representation through a hydraulically assisted electromechanical brake;
• 4b : Basic circuit diagram of possible valve circuits and their function for reducing pressure in a wheel brake;
• 4c : Actuator ( BE ) with associated piston-cylinder unit with hydraulic connection line to a brake circuit;
• 5 : Pressure supply device with two control and regulating devices;
• 6a : Moment diagrams for the representation of the brake force support by means of a hydraulically assisted electromechanical brake and traction motor;
• 6b : Moment diagrams to show the possibility of downsizing the pressure supply device, provided that the braking force is supported by means of a hydraulically assisted electromechanical brake and traction motor;
• 6c : Moment diagrams for the representation of the brake force support by means of a hydraulically assisted electromechanical brake and traction motor in emergency operation in the event of failure of components of the brake system;
• 6d : Moment diagrams to show the course of the braking torque during the request for brake fluid with the brake force support by means of a hydraulically assisted electromechanical brake and traction motor;
• 6e : Brake pressure control in the event of a pressure transmitter failure using current and temperature measurement and evaluation of the pressure-volume characteristic.

The 1 shows a schematic representation of a first embodiment of the inventive brake system with two pressure supply devices DV1 and DV2 which are used to supply pressure to the wheel brakes RB1-RB4 of brake circuits BK1 and BK2 or an axis VA , HA serve. The pressure supply devices each have two control and regulating devices DV ECU1 and DV ECU2 and a valve assembly R-HCU , wherein the components of the pressure supply devices DV1 and DV2 via two on-board networks or power supplies BN1 and BN2 provided. There are also redundant signal lines DS1 , DS2 to the control and regulating devices (shown in 5 , not shown in 1 ) to the central control unit M-ECU preferably provided. Each ECU is used to control each one of the two winding or 3-phase systems (1-3ph DV-ECU1 , 1x3Ph DV-ECU2 ) of the drive motor of the pressure supply device DV1 and DV2 ). On the rear axle HA are two traction motors in this embodiment TM1 and TM2 arranged for driving and braking the vehicle wheels. The braking system also has an actuating device BE on which a brake pressure can be built up in the wheel brakes in the event of a fault, in this version in the wheel brakes of the front axle VA . The traction motors TM1 and TM2 provide support in the fallback level, ie failure of the pressure supply when braking the rear axle HA . The components of the pressure supply devices are used to increase the reliability DV1 and DV2 each via two independent on-board networks BN1 and BN2 supplied, two different voltage levels can be provided instead of the on-board network.

The 1a shows a schematic diagram of a first possible embodiment of the brake system according to 1 with EPB electric parking brake. The pressure supply device DV1 takes over the pressure supply for the front axle VA with the two wheel brakes RB1 and RB2 , in addition an electric power steering EPS is provided. By means of the switching valves SV1 and SV2 and the optional exhaust valve AV1 can by means of the pressure supply device DV1 the pressure in the wheel brakes can be adjusted sequentially or simultaneously. It is possible that pressure builds up in the wheel brake RB1 by adjusting the piston KB the pressure supply device DV1 and a simultaneous pressure reduction in the wheel brake RB2 by opening the exhaust valve. The pressure control in the wheel brakes is preferably carried out in multiplex operation MUX and can either be by means of the pressure measured in the brake circuit - or via the motor current i _phase , the position of the piston KB and a pressure-volume characteristic curve take place. Optionally, the temperature of the motor can also be used M1 measured and used for more precise pressure control.

The same applies to the pressure control in the rear axle HA by means of the pressure supply device DV2 and the switching valves TV , SV3 and SV4 and the optional exhaust valve AV2 he follows. The pressure is controlled by means of the pressure transmitter p / U. If the pressure transmitter fails _, the pressure is controlled via the measured motor current i _phase, the rotor angle α and optionally by means of the measured motor temperature T of the drive motor M2 the pressure supply device DV2 .

If the pressure supply device fails, the pressure in the wheel brakes of the front axle can be actuated BE take place by means of the brake pedal 1 The piston 3rd in the cylinder 5 is adjusted and thus hydraulic medium from the pressure chamber 4th in the brake circuit BK of the front axle VA is promoted.

A higher-level control unit M-ECU controls the individual control and regulating units of the components of the brake system. This is particularly useful for a holistically optimized driving dynamics control, where, for example, synergies from steering, yaw moment control via brake, torque vectoring via brake and traction motor, interaction of brake and electric motor in vehicle deceleration can be achieved.

The pressure supply devices DV1 and DV2 each have redundant control and regulating units DV1-ECU and DV2-ECU which separately control the separate winding systems or phase system of the drive motors, so that even if one winding system of a motor fails M1 , M2 or a control and regulating unit, the respective pressure supply device can still be used with reduced power for pressure control.

The 1b shows a schematic diagram of a second possible embodiment of the brake system according to 1 . Here are the wheel brakes RB3 and RB4 the rear axle HA thanks to hydraulically assisted electromechanical brakes H-EMB formed with which in normal operation not only by means of the pressure supply device DV2 but also a braking torque can be generated by means of its own electric drive. This can be used to support braking, torque vectoring, yaw moment control or in the event of a total brake failure. In addition, the traction drive can be used TM1 a deceleration of the vehicle wheels is generated in support or alone. On the front axle VA is also a traction drive TM2 as well as an electric power steering EPS with associated control and regulation units EPS ECU and TM-ECU arranged. All components of the braking system are controlled by the central control unit M-ECU controlled.

The 2nd shows a schematic representation of a second possible embodiment of the inventive brake system with two pressure supply devices DV1 and DV2 which are used to supply pressure to one axis each VA , HA one control and regulating device each DV-ECU1 and DV-ECU2 and a common valve control unit R-HCU or. VM-ECU have, each component of the pressure supply devices DV1 and DV2 is supplied via two on-board networks or power supplies or voltage levels. R-HCU includes the solenoid valves of the wheel brake control, VM-ECU comprises the valve circuit which ensures that either the brake circuits can be connected to one another, separated from one another and / or one or both brake circuits can be connected to the reservoir.

The 3rd shows a schematic representation of a third possible embodiment of the inventive brake system with two pressure supply devices DV1 and DV2 which are used to supply pressure to the wheel brakes of one axle VA , HA are provided, each of these two control and regulating devices DV-ECU1 and DV-ECU2 and a valve arrangement with a control unit R-HCU have, each component of the pressure supply device via two on-board networks or voltage supplies BN1 and BN2 is supplied and both brake circuits via a connection module VM are connectable or separable. Instead of an actuator BE , in which hydraulic pressure can be built up in the wheel brakes via the brake pedal, has the brake system according to 3rd an electronic brake pedal, which provides a break-by-wire braking system. The signals from the electronic brake pedal are generated by the central control unit M-ECU processed and the components of the brake system controlled accordingly.

The 3a shows a schematic diagram of a first possible embodiment of the brake system according to 3rd . The connection module VM also has a control unit VM-HCU and has a valve circuit that ensures that either the brake circuits from the front axle VA and rear axle HA separated from each other or connected to each other or one or both brake circuits with the chamber K1 of the storage container VB is in hydraulic connection. The pressure control in the wheel brakes can either be carried out using the pressure transmitter p / U or by measuring the current and using the pressure volume characteristic. The pressure reduction in the wheel brakes RB2 and RB3 , but also RB1 and RB4 by opening the switching valves SV1 to SV4 can optionally also via the optional exhaust valves AV1 and AV2 respectively.

The braking system according to 3b differs from that in 3a illustrated only by the fact that no exhaust valves AV are provided. For this purpose, the drive motor of the pressure supply must be designed to be highly dynamic, e.g. in the form of a motor with a double air gap ( US 7872389 B2 ) or other braking power generating units such as traction motors, H-EMB (not shown) be included in the braking force control.

The 3c shows the braking system according to 3b with the fault that occurs at the pressure supply device DV2 a phase winding of the motor can no longer be controlled. In this case, however, the pressure control can continue to be operated with the redundant winding systems and control and regulating units of the pressure supply devices. However, the pressure supply device DV2 for the wheel brakes RB3 and RB4 no longer adjust the maximum brake pressure and no longer with the high dynamics. In this case, the torque of the traction drive TM the rear axle can be used to generate an additional braking torque, whereby the blocker pressure or maximum deceleration can still be achieved despite half the torque of the pressure supply device. The performance is limited, however, so that the individual wheel control has a poorer performance in this case and the braking distance increases, especially when operating on high road friction in ABS operation. In any case, a high level of safety and control quality can be achieved, which is superior to the current HAD level systems.

The 3d shows the error case F2 , in which the pressure supply device of the rear axle HA has totally failed. In the event of a fault, the brake circuits are connected to one another via the connection module and the pressure supply device DV2 the front axle takes over the pressure control, preferably in multiplex mode for all wheel brakes RB1-RB4 . The braking force of the traction drives can also be applied in the event of a fault TM be used to decelerate the vehicle. As in 3c executed, this error case leads to reduced performance, but not to security risks.

The 3e shows the replenishment of brake medium from the chamber K2 into the pressure supply device DV1 in which the piston KB is adjusted to the right or withdrawn. By closing the switching valves SV1 and SV2 with the isolation valve open TV2 can then the medium via the connection module from the pressure supply device DV1 into the chamber K1 of the storage container VB are pressed in order to refill them or alternatively can be replenished from this chamber of the storage container. This results in further redundancy.

The 4a shows a cross-sectional view through a hydraulically assisted electromechanical brake H-EMB which is connected to the pressure supply device via a hydraulic connection HL-DV1 DV1 is connectable so that either via the hydraulics and / or the electric motor EM a force can be applied to the brake discs. The rotor movement of the electric motor is hereby transferred into a linear movement via a gearbox G and generates the force F _EM on the wheel brake. The transmission G is preferably designed to be self-locking, so that the parking brake functions reliably when the vehicle electrical system is at a standstill. In addition to the electric motor, a hydraulic power is generated via the pressure supply F _hyd generated. Depending on the version of the EM As a brush motor or brushless motor, with low or higher power, the dynamics of the braking torque change and the additionally available braking torque can be achieved by H-EMB be determined by appropriate design of the components and matched to the hydraulic brake.

The 4b shows a possible valve circuits and their function for pressure control in the four wheel brakes RB1 to RB4 according to the valve circuit from 3a (just AV on wheel brake RB2 executed, not on RB3 ). The pressure build-up and pressure reduction in the wheel brakes is preferably carried out via the pressure supply device DV1 with the switching valves open SV1 or. SV2 in the wheel brakes RB1 and RB2 , as well as about the DV2 with the switching valves open SV3 and SV4 in the wheel brakes RB3 and RB4 . Control is carried out either with pressure as a controlled variable, supported by the PPC process, for example by suitable pilot control, or, if a pressure transmitter is not available, only by the PPC process. In addition, the pressure of the wheel brake can be adjusted RB2 via the outlet valve AV in the storage container VB be drained, for example by PWM control of the AV valve, in which case AV is open and SV2 closed is. At the same time, the DV1 a build up of pressure in RB1 by opening the switching valve SV1 respectively. A combination of the PPC process with the PWM control is also a possible control process. Here are both switching valves SV1 and SV2 opened or a switching valve or both switching valves are clocked in the PWM process and exhaust valve AV is either open or is also clocked. This method is an alternative to the known multiplex method, where switching valves are opened or closed digitally and the pressure is reduced sequentially or simultaneously and builds on the method in DE 102015103858 on. The valve circuit can be expanded with additional exhaust valves (1 AV each in RB 3rd see. 3a , or AV valves on three or all wheel brakes in all wheel brakes), provided that further degrees of freedom are required when reducing pressure. The switching valves SV1-4 are arranged and designed such that they open automatically due to the pressure enclosed in the wheel brakes. This ensures that no brake pressure is locked into the wheel even if the entire system fails.

The 4c shows an embodiment of an actuator BE with brake pedal 1 , Pestle 2nd , Piston 3rd , Cylinder 5 and pedal feel simulator 6 to build up pressure in one or more brake circuit (s) BK1 or. BK2 . The piston 3rd ,, the 3 seals x in the cylinder 5 has, is over the plunger 2nd from the brake pedal 1 adjusted to the left, resulting in the pressure chamber 4th a pressure builds up or a pressure volume via the hydraulic line HL into the brake circuits BK1 / BK2 is promoted. In addition, redundant seals in the cylinder and parallel hydraulic lines to the reservoir are each provided between the seals, one seal having a throttle. This means that the failure of a seal can be reliably diagnosed and there is a reliable actuation system with pedal feel simulator and sealing system with multiple redundancy as well as the possibility of generating pressure in the event of failure of the electromotive pressure supply device.

The 5 shows a possible embodiment of a pressure supply device DV1 with two control and regulating devices DV-ECU1 and DV-ECU2 . The pressure supply device has an electric motor M1 on whose rotor R a spindle SP adjusts which with a piston KB is connected. By adjusting the piston KB can be a pressure in the pressure chamber DR be built up, which via the isolating valve TV can be routed into a brake circuit BK. The piston is sealed by several redundant seals in the cylinder, like in the actuation unit BE a redundant diagnosable sealing system is created. In the pressure supply device too, a hydraulic line leads between the seals to the reservoir. This means that the pressure supply is still fully operational and redundant even if one seal fails. The pressure chamber is via a check valve DR connected to the reservoir. The pressure supply can thus be replenished. Each of the two control and regulating devices DV-ECU1 and DV-ECU2 are via 1x3 phase lines with separate winding or phase systems of the motor M1 in connection, so that if a control and regulation device or a winding system fails, the motor M1 can still be operated via the other winding or phase system and the other control and regulating device, even if then only about half the torque by means of the drive M1 can be generated. One or both control and regulating device (s) has sensors for determining the temperature T, the motor current i and the rotor angle of the electric motor α. To Achieving high availability are not just control and regulating devices DV-ECU redundant, but also power supplies BN1 , BN2 as well as data and control lines DS1 and DS2 provided twice. The power supplies BN1 and BN2 can be, for example, different voltage levels of an on-board electrical system or separate on-board networks.

The 6a shows moment diagrams for the representation of the brake force support by means of hydraulically assisted electromechanical brake H-EMB and traction motor TM . In the diagram on the left is the torque curve M _{hyd, DV1} , which alone by means of the pressure supply device DV1 is achievable. The right-hand diagram shows the torque curve, as with the addition of the hydraulically assisted electromechanical brake H-EMB and a traction motor TM is achievable. There is a maximum torque M _max , _H-EMB from H-EMB or. M _{max, TM} of the traction motor. Thanks to the additional traction motor TM generates braking torque M _{max, TM} as well as using the H-EMB generated braking torque ΔM _H-EMB the blocking pressure (horizontal dashed line) is reached by the time period Δt. A significantly larger braking torque can also be generated.

The 6b shows the possibility of downsizing the pressure supply device DV1 provided the braking effect of the hydraulically assisted brake ( H-EMB ) according to 4a is included in the pressure control. So should the pressure supply device DV1 not be reduced in terms of their maximum build-up pressure, but in terms of their dynamics, which makes the electric motor cheaper to manufacture.

The 6c shows moment diagrams for the representation of the brake force support by means of hydraulically assisted electromechanical brake H-EMB and traction motor TM in emergency mode if a winding or phase system fails 1x3 phases of the drive M1 . By eliminating a winding system, the pressure supply can DV1 no longer build up the required pressure up to the blocking pressure and is also no longer dynamic enough. By using the hydraulically assisted electromechanical brake H-EMB as well as the traction motor (s), the required dynamics and the required brake pressure can be built up (right diagram).

The 6d shows moment diagrams for representing the braking torque curve Mbrems during the supply of brake fluid. During re-feeding from the storage container VB can by means of the pressure supply device DV1 no further brake pressure can be built up. By adding the braking torque M _{max, TM} of the traction motor TM as well as using the H-EMB generated braking torque ΔM _H-EMB The braking torque Mbrems can also be increased further during the subsequent conveying, as a result of which the dynamics of the system are significantly improved.

The 6e shows a brake pressure control if the pressure transmitter fails DG , then by means of current measurement of the motor current i _phase and evaluation of the pressure-volume characteristic curve, a regulation of the engine torque M _Mot and thus the regulation of the pressure p is carried out. The engine temperature T is also taken into account, since the torque constant is reduced under temperature and thus has an influence on the proportionality factor kt * (1-Br% * ΔT) between engine torque M _Mot and motor current i _phase . This advantageously results in a redundancy of the pressure measurement. So there is no need for a pressure transmitter. The control is calibrated by the pressure transmitter and it is primarily controlled with current, path and pressure volume characteristic.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 112009005541 B3 [0003, 0018]
• DE 102005055751 B4 [0009, 0034]
• DE 102005018649 B4 [0009]
• EP 1874602 B1 [0010]
• EP 2396202 B1 [0010]
• EP 1759447 B1 [0010]
• WO 201614622 A2 [0011]
• EP 3271221 A2 [0012]
• WO 2012059175 A1 [0013]
• DE 102007015809 [0047]
• US 7872389 B2 [0060]
• DE 102015103858 [0065]

Claims (32)

Brake system for a vehicle, comprising the following components: - at least two hydraulic brake circuits (BK1, BK2), each with at least one hydraulic wheel brake (RB1, RB2, RB3, RB4), - at least two pressure supply devices (DV1, DV2), each with a piston -Cylinder unit, the pistons of which are driven by an electric motor drive (M1, M2) via a gear, in particular a spindle drive, - at least one valve arrangement (HCU) with valves for wheel-specific setting of brake pressures and / or for separating or connecting the Wheel brakes (RB1, RB2, RB3, RB4) with a pressure supply device (DV1, DV2) - at least one electronic control and regulation unit, characterized in that - at least one pressure supply device (DV1, DV2) two mutually independent electronic control and regulation units (ECU1 , ECU2) or a double redundant control and regulating unit (DV1-ECU, DV2-ECU) to control your electr has motor drive (M1, M2), and / or - each pressure supply device (DV1, DV2) is assigned to a brake circuit (BK1, BK2) for the normal operation of the brake system, and that a connection module (VM) for the optional connection of the brake circuits (BK1 , BK2) is provided in such a way that if one pressure supply device (DV1, DV2) fails, the pressure supply or pressure control for both brake circuits (BK1, BK2) takes place through the other pressure supply device (DV1, DV2) that is still functioning. Braking system after Claim 1 , characterized in that at least one, in particular each, electronic control and regulating unit (ECU1, ECU2) controls separate windings of the or an electromotive drive (M1, M2). Braking system after Claim 1 or 2nd , characterized in that either each pressure supply device (DV1, DV2) each has a, in particular redundant, valve arrangement (R-HCU) or two pressure supply devices (DV-ECU1, DV-ECU2) is assigned a redundant valve arrangement (R-HCU), the a redundant valve arrangement (R-HCU) is designed such that if one or both control and regulating units ECU of the pressure supply device (DV1, DV2, DV-ECU1, DV-ECU2) fail, the solenoid valves of the pressure supply can still be operated. Braking system after Claim 3 , characterized in that the pressure supply device (DV1, DV2) together with the valve arrangement (R-HCU) and the at least one electronic control and regulating unit assigned to the pressure supply device are combined to form a module or assembly. Brake system according to one of the preceding claims, characterized in that the brake system has a pedal feel simulator (BE). Brake system according to one of the preceding claims, characterized in that a piston-cylinder unit with a piston (HZ) which can be actuated by means of an actuating device, in particular in the form of a brake pedal, is provided and can be connected or connected to at least one hydraulic brake circuit. Brake system according to one of the Claims 1 to 5 , characterized in that an actuating arrangement is provided in the form of an electronic brake pedal. Braking system according to one of the preceding claims, characterized in that the braking system is operated in closed-loop control mode, that is to say no pressure is released in the storage container via solenoid valves in the closed-loop control mode, and / or the pressure in the wheel brakes (RB1-RB4) of the respective brake circuit ( BK1, BK2) is multiplexed and / or adjusted or set simultaneously. Braking system after Claim 8 , characterized in that the switching valves are connected to the wheel brakes in such a way that they open automatically due to pressure in the wheel brake. Brake system according to one of the preceding claims, characterized in that a pressure reduction in control operation, in particular in the case of very high pressure dynamic requirements, for example in the case of high-µ ABS control, in particular in the event of a failure of a pressure supply DV1, DV2 or an ECU of a pressure supply in a wheel brake RB4) by opening an outlet valve (AV) into the reservoir (VB), especially in extended multiplex operation (so-called MUX 2.0 process), in which a pressure supply device (DV1, DV2) takes over the pressure control for all wheel brakes (RB1-RB4) , he follows. Brake system according to one of the preceding claims, characterized in that at least one wheel brake, preferably two wheel brakes, is a hydraulically assisted electromechanical brake (H-EMB), an electric parking brake (EPB) or an electromechanical brake (EMB) or in addition to the wheel brake (RB1 -RB4) an additional parking brake (EPB) or electromechanical brake (EMB) has a braking effect on the wheel. Brake system according to one of the preceding claims, characterized in that the brake system, in particular also the electronic control and regulating units (ECU1, ECU2) of the pressure supply devices (DV1, DV2), is controlled by a higher-level control unit (M-ECU). Braking system after Claim 12 , characterized in that, in addition to the braking system, at least one electric drive motor (TM1, TM2) is provided for at least one axle or wheel of the vehicle and is used for braking an axle or a wheel. Braking system after Claim 12 or 13 , characterized in that the higher-level control unit (M-ECU) when braking, in particular with recuperation, determines the braking torque to be generated by means of the wheel brakes (RB1-RB4) and the electronic control and regulating units (ECU1, ECU2) of the pressure supply devices (DV1, DV2) controls accordingly and / or controls or uses the at least one electric drive motor (TM1, TM2) to build up a braking torque generated in addition to the wheel brakes (RB1-RB4). Brake system according to one of the preceding claims, characterized in that the higher-level control unit (M-ECU), the pressure supply devices, valves, electric drive motors (TM1, TM2) and / or EMB or H-EMB during the braking process and / or ABS control mode and / or controlled for diagnosis of the brake system. Brake system according to one of the preceding claims, characterized in that each pressure supply device (DV1, DV2) is assigned at least one isolating valve (TV), the pressure supply device (DV1, DV2) being closed by the isolating valve (TV), in particular in the event of its failure, by which respective brake circuit (BK1, BK2) can be disconnected. Brake system according to one of the preceding claims, characterized in that at least one ECU of a pressure supply (DV-ECU1, DV-EUC2) and a valve arrangement (R-HCU) have a separate voltage supply and in particular signal transmission, in particular all modules (DV-ECU1, DV -ECU2, R-HCU) are supplied by at least two on-board networks (BN1, BN2) and have redundant signal transmissions (DS1, DS2). Brake system according to one of the preceding claims, characterized in that either the pressure control in a brake circuit (BK1, BK2) using at least one pressure sensor and / or via the current measurement of the motor current of the drive and displacement control of the piston of the pressure supply device, in particular taking into account the temperature of the Drive. Brake system according to one of the preceding claims, characterized in that the connection module (VM) either has - three solenoid valves (BV1, BV2, ZEA) via which a hydraulic connection between a brake circuit (BK1, BK2) and the reservoir (VB) or between the two brake circuits (BK1, BK2) can be produced or - is formed by a piston-cylinder unit, the piston of which separates a first and a second pressure chamber from one another, the first pressure chamber with the one brake circuit (BK1) and the second pressure chamber with the another brake circuit (BK2) is connected and the piston can be locked by means of a blocking device. Brake system according to one of the preceding claims, characterized in that it has redundant seals and redundant regulating and control units (ECU, ECU1, ECU2), and that the drives (M1, M2) of the pressure supply devices (DV, DV1, DV2) have 2x3 phases , and that the motor current (i), the rotor angle (α), in particular the temperature (T), are measured by sensors and taken into account in the pressure control, and that there is a redundant supply via two on-board networks (BN1, BN2) or voltage levels, and that a redundant signal transmission (DS1, DS2) is provided. Brake system according to one of the preceding claims, characterized in that a combined use of pressure supply devices (DV, DV1, DV2), hydraulically assisted electromechanical brake (s) (H-EMB), electrical (n) parking brake (s) (EPB) and / or electromechanical brake (s) (EMB) and / or drive motor (s) (TM, TM1, TM2) in normal operation for a faster increase in braking force with a shorter time to lock (TTL) or if one or more components of the braking system fail . Reservoir (VB) for brake system according to one of the preceding claims, characterized in that the reservoir has a plurality of chambers (K1, K2), one chamber (K2) of the reservoir (VB) with at least one pressure supply device (DV, DV1, DV2) hydraulic is connected or connectable and / or a further chamber (K1) is hydraulically connected or connectable to the connection module (VM). Method for operating a brake system according to one of the preceding claims, characterized in that at least axially, preferably individually, the deceleration of the wheels by means of the pressure supply device (s), the electric drive motor (s) (TM) and the hydraulically supported electromechanical Brake (H-EMB) or the electromechanical brake (EMB). Method for operating a brake system according to one of the preceding claims, characterized in that torque vectoring by means of the pressure supply device (s), the electric drive motor (s) (TM) and the hydraulically assisted electromechanical brake (H-EMB) or the electromechanical brake (EMB). Method for operating a brake system according to one of the preceding claims, characterized in that the temperature (T) of the drive is determined using a temperature sensor and the temperature (T) is used for a more precise determination of the torque torque constant kt, which is caused by the temperature increase by the factor (1-Br% * ΔT) linearly reduced and this is used for more precise torque / pressure control based on the phase current = kt (T) * phase current i. Procedure according to Claim 24 or 25th that the piston position and the pressure volume characteristic curve are used for pressure control in addition to the current control and the change in the pressure volume characteristic curve with influencing factors, such as air inclusion, is adjusted by the pressure transmitter or the H-EMB. Procedure according to Claim 25 and 26 , characterized in that a high-precision pressure control without a pressure sensor is possible by using both methods in combination and this method is preferably used in the event of failure of components or at least one pressure sensor. Method for operating a brake system according to one of the preceding claims, characterized in that to control the driving stability, the wheel-specific control options via at least one pressure supply (DV1, DV2) and the hydraulically supported electromechanical brake (s) (H-EMB), electrical (n) Parking brake (s) (EPB) and / or electromechanical brake (s) (EMB) are used. Method for operating a brake system according to one of the preceding claims, characterized in that for steering / torque vectors the wheel-specific control options via at least one pressure supply (DV1, DV2) and the hydraulically supported electromechanical brake (s) (H-EMB), electric parking brake (s) (EPB) and / or electromechanical brake (s) (EMB) and / or drive motors (TM1, TM2) or the steering (EPS) can be used. Method for operating a brake system according to one of the preceding claims, characterized in that the pressure supply (DV1, DV2) delivers fluid from the reservoir (VB) when the isolation valve (s) (TV2, TV1) is closed or closed. Method for operating a brake system according to one of the preceding claims, characterized in that a combination of the PPC method with the PWM control is used as the control method, wherein both switching valves (SV1, SV2) are open or a switching valve or both switching valves by means of PWM Processes are clocked and the outlet valve (AV) is opened for pressure reduction, in particular with PWM for controlled pressure reduction. Method for operating a brake system according to one of the preceding claims, characterized in that the pressure supply device of the brake system has no redundant control and regulating device DV-ECU, and that in the event of a fault, the driver builds up pressure by means of the actuating device (BE), an additional one Deceleration torque is generated by the motor (TM), and optionally at least one hydraulically assisted brake (H-EMB) is provided.

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