Driving dynamics system, vehicle, and method of operating a driving dynamics system

Abstract

The present invention relates to a driving dynamics system for a vehicle, comprising at least one wheel brake (RB1, RB2, RB3, RB4) for dissipatively braking a wheel of the vehicle, at least one brake unit (EMB, EHB) assigned to the at least one wheel brake (RB1, RB2, RB3, RB4) and configured to generate a dissipative braking torque with the at least one wheel brake (RB1, RB2, RB3, RB4), and a drive brake for generating a regenerative braking torque for at least one wheel or axle of the vehicle. a central control unit (M-ECU) configured to drive and control the at least one brake unit (EMB, EHB) and the at least one electric traction motor (TM1, TM2, TM3, TM4) in combination with each other for a braking function, such that a combined braking torque can be generated by means of the at least one brake unit (EMB, EHB) and the at least one electric traction motor (TM1, TM2, TM3, TM4). DOMAENE ), wherein the braking function relates to a control case of simultaneous open-loop and / or closed-loop control of a basic braking torque and a closed-loop controlled additional braking torque, optionally in which the basic braking torque is generated by at least one brake unit (EMB, EHB) and the closed-loop controlled additional braking torque is generated by at least one electric traction motor (TM1, TM2, TM3, TM4), or in which the basic braking torque is generated by at least one electric traction motor (TM1, TM2, TM3, TM4) and the closed-loop controlled additional braking torque is generated by at least one brake unit (EMB, EHB), or in which at least one brake unit (EMB, EHB) and at least one electric traction motor (TM1, TM2, TM3, TM4) respectively together generate the basic braking torque and the closed-loop controlled additional braking torque.

Description

[Technical field]

[0001] The invention relates to a driving dynamics system (FDS) with one or more electric traction motors and a powerful central computer, which are synchronously controlled via the central computer in such a way that basic braking and control operating functions are commonly controlled in the traction motors and the brake modules (EMB, EHB). The invention further relates to a vehicle with the driving dynamics system and to a method for operating the driving dynamics system.

[0002] Preferably, the brakes and the electric traction motors are integrated as a wheel module or an E-vehicle axle module, in which the wheel brakes and the electric traction motors are driven synchronously via a separate wheel module or a separate axle module control device.

[0003] The automotive industry is undergoing a continuous transformation: in addition to the increasing market penetration of electric vehicles, different levels of automated driving are progressing, starting with Level 3 - Highly Automated (HAD), Level 4 - Fully Automated (FAD) and Level 5 - Autonomous (AD), with each successive level placing increasing demands on the systems used to control the driving dynamics.

[0004] From level 4 (FAD), at least two-fold and better three-fold redundancy is expected for sufficient system availability, e.g. for pedal sensors with the “2-out-of-3” rule. Furthermore, for autonomous driving from level 3 onwards, and especially from level 4 onwards, individual redundant braking torque control for each wheel is required. At level 5 (AD), the steering wheel as well as the brake and accelerator pedals are possibly omitted completely and the vehicle is steered solely by a central computer. Since the driver will no longer be able to intervene via the brake pedal or steering wheel in the event of a system failure, an error-resistant two- or three-fold redundancy is required with degraded steering as well as all core functions of the brakes (brake force amplification, ABS, vehicle stabilization).

[0005] Furthermore, a domain structure is introduced by the control unit or control domain for chassis control, which includes brakes, electric drive, steering and, optionally, damping. The central control unit allows the vehicle manufacturer to take responsibility for the above-mentioned equipment and, as a result, to optimally utilize synergies. However, at the same time, the necessary redundancies must be ensured, since new requirements have to be met based on the shifting of liability from the vehicle driver to the vehicle manufacturer. Furthermore, autonomous vehicles of levels 3 to 5 must not be parked on the shoulder of the road. At least a limp-home mode is more desirable than continued operation in the event of a partial failure, since autonomous vehicles are aimed at a long period of use.

[0006] As friction brake systems, electrohydraulic brake systems (abbreviated EHB) or electromechanical brakes (abbreviated EMB) as well as a base brake with brake jaws and brake discs are available. EMB has the disadvantage of being more expensive than EHB, since an EMB is required for each wheel. However, EMB has the advantage that it can be controlled much more easily centrally, since a central driving dynamics control system FDS with ABS and ESP functions can be developed independent of the brake manufacturer, and the integration of electromechanical brakes into domains and applications is much easier than that of electrohydraulic brakes. This is especially true in comparison with standard ABS systems with an open brake circuit, which require highly complex and adaptively learning pressure estimation models. The increasing popularity of EMB is therefore not primarily motivated by component costs, but by lower application costs and easier integration.

[0007] A typical vehicle architecture with an E-drive for SAE levels 3-4 is shown in Fig. 1a (wherein in Fig. 1a reference is made to https: / / www.lsp-ias.com / our-world / chassis-control), where for example according to WO 2019 / 214833 an electric friction brake system with a brake booster and an ESP unit is used.

[0008] It is further known from WO 2019 / 002475 that the brakes can be controlled centrally as pressure regulators via a central computer, i.e. a domain, whereby the braking torque is determined in the central computer and the electrohydraulic brakes are used solely as pressure regulators for implementing a target braking torque or target pressure.

[0009] Furthermore, WO 2020 / 165255 A1 discloses an electrohydraulic brake system in which braking is carried out or assisted via an electric traction motor and / or an electric parking brake in the event of a failure or partial failure of the pressure supply device.

[0010] Furthermore, so-called combined brakes are known from WO 2019 / 215278, in which an electrohydraulic brake (EHB) is used on the front axle and an electromechanical brake (EMB) or a hydraulically assisted electromechanical brake (H-EMB) is used on the rear axle.

[0011] WO 2020 / 128081 considers an E-axle module in which a pressure regulator supplies pressure to hydraulic consumers, in particular hydraulic wheel brakes.

[0012] WO 2018 / 215397 considers the idea of ​​a central control of the electric motor brake and the electrohydraulic brake, with emphasis on the minimum time to achieve the locking pressure (time-to-lock, TTL for short). Furthermore, the braking function is implemented exclusively via the electric traction motor depending on the driving situation by using a vehicle model.

[0013] In WO 2021 / 037658, another idea of ​​central control of an electric traction motor and an electrohydraulic brake is realized, i.e. central control of electric braking force distribution simultaneously with regeneration via an electric motor.

[0014] The overall optimization of the driving dynamics control and the cost reduction by utilizing the synergy of the EMB or EHB combined with the electric traction motor are fundamentally examined in both cases in the prior art, because the brake-by-wire brake and the braking via the electric traction motor are considered as separate units and the braking via the electric traction motor is limited to a deceleration of about 0.3 g for safety reasons and liability reasons, in particular to avoid safety-critical driving situations. Furthermore, the battery is technically limited in terms of energy absorption, especially in the full state of charge (SOC) of the battery, when regenerative energy is generated via the electric traction motor, which requires an energy sink. The synergy potential of the joint utilization of the drive motor and the brake is extremely high, because the electric drive motor is becoming more and more powerful and dynamic in the development of electric vehicles due to the high-voltage technology (especially 400 V or 800 V) and thus has the potential to contribute decisively to the reduction of the braking distance. In particular, the combined use of electric traction motors in highly dynamic brake control processes, especially ABS control, offers enormous potential for new and innovative approaches.

[0015] Also, the potential for utilizing different units during acceleration and braking while simultaneously achieving downsizing and cost reductions and improving performance through central control was not examined.

[0016] Furthermore, the application costs of the brakes are currently characterized by a very wide range of application behaviors, and prior art braking systems with ABS control (EP 2536607, EP 3036136) require complex pressure models that must be adapted to the respective vehicle with preload control via a plunger, pressure build-up via an inlet valve and pressure reduction with time control via an outlet valve. Therefore, numerous application engineers work for many years to apply the vehicle to all driving situations and friction value conditions.

[0017] The object of the present invention is to provide a driving dynamics system (FDS) with a central domain control via a driving dynamics domain or a central computer and with wheel modules or vehicle axle modules with a number of brake units (electric traction motors, electrohydraulic pressure regulators (EHB) and / or electromechanical brake actuators (EMB)), in such a way that the synergy between the individual brake modules is maximized for the realization of the braking task. In this case, it is desirable to minimize the total cost, weight and thermal load of the components of the brake system. At the same time, it is desirable to minimize the braking distance and ensure driving stability.

[0018] For this purpose, the wheel or axle modules should preferably be controlled in such a way that each wheel or each vehicle axle only executes a target braking torque and the distribution of the braking torque to each wheel or each axle is calculated in a central computer, where the characteristic functions, i.e. anti-lock braking system ABS, anti-slip control ASR, electric stability program / electric stability control ESP / ESC, electronic brake force distribution EBV and regenerative braking management are also realized. The task of the control electronics of the wheel or axle modules is, however, to distribute the target braking torque to the different brake units of the wheels or vehicle axles.

[0019] Furthermore, for vehicles equipped with a corresponding driving dynamics system (FDS), a method for controlling the vehicle in highly dynamic braking operations (emergency braking function AEB and in particular subsequent ABS control operations) should be provided, which method is optimized with respect to the braking distance and thus optimizes the controllability in critical driving situations (ABS operation on snow or ice), and the brake module should be configured so that it allows for rapid application, in particular so that application can be performed automatically.

[0020] Furthermore, the brake module advantageously has the concept that interruptions in the control operation are realized by re-pumping of the hydraulic volume by a device integrating two commercially available brake systems (DE 102018212905 A1, DE 102019204016 A1) as taught by EP 2 580 095 A1, or are avoided or prevented by dead times in a multiplex control method, or are compensated by control interventions via an electric traction motor.

[0021] Furthermore, the brake module preferably comprises a diagnosable valve arrangement between the pressure supply unit and the hydraulic consumer, in particular one or more wheel brakes of an axle, in particular a pull-resistant wheel valve (MV 1 in FIG. 6a below) designed for a bidirectional volume flow, i.e. both during pressure build-up and during pressure release. 2k,1 ,MV 2k,2 ,MV 2k,3 ,MV 2k,4 ) and / or circuit isolation valves (hereinafter referred to as MV 2k,v The concept is that in the event of a leak in a consumer, a valve device is provided, which closes the valve device, thereby isolating the corresponding consumer and allowing the system to be further operated in a smaller form with another consumer.

[0022] In the prior art (EP 3036136), for example, check valves (shown as inlet valve 88 and check valve 92 in FIG. 1 of EP 3036136) are provided in the parallel circuit leading to the wheel inlet valves, which are necessary to ensure that the pressure in the wheel brakes can still be reduced in all circumstances, particularly in the event of a failure of the ECU or the energy supply.

[0023] In contrast, the new design with the retraction-resistant valve arrangement has the decisive advantage that a fault in the wheel circuit can be diagnosed unambiguously, since the uncertainty as to whether the leak is caused by the changeover valve or the check valve is eliminated. If a valve leak or a fault in the hydraulic line to one or more wheel brakes is diagnosed, for example by a method as described in WO 2018 / 011021, the hydraulic circuit is reliably isolated by closing the valve and the brake system is driven for a short time by only one consumer. This has a decisive advantage over brake systems with typically two brake circuits and four wheel brakes (referred to in the prior art as monochromatic brake circuits (II) or diagonal brake circuits (X)), in which two wheel brakes must be directly switched off in the event of an error. The advantages of the new valve arrangement are considerable, since the deceleration that can be achieved with three wheel circuits instead of two even in the event of an error is significantly higher, and furthermore the yaw moment intervention and steering intervention for the ESP can be maintained with three wheel circuits without significant performance losses. In addition, if an electric drive motor is available for driving and braking the failed wheel and is integrated into the control unit, braking torque control using the four wheel brakes in error cases is also possible.

[0024] Furthermore, the brake system should be configured so that easy application of core functions via a central control unit, in particular due to the high computing power of a central or domain computer, is automatically obtained in the application of functions during development, and in particular so that it is adaptable during vehicle operation, via learning algorithms or artificial intelligence (AI), both before the first start of operation of the vehicle and during subsequent operation, for normal operation in the absence of errors and for adaptation operation in the event of an error.

[0025] In the case of an AI approach, a powerful central computer with sufficient performance can take on the task of the application engineer, which is not possible with prior art microcontrollers such as those provided in known closed-loop and open-loop control units of braking systems due to their very limited performance and memory. Thus, the central computer records and evaluates measurement data during vehicle operation and applies various functions, in particular the safety-critical functions ABS, ESP and AEB, during vehicle operation or in the vehicle stationary state when the vehicle is not moving and therefore the adaptation is not time-critical.

[0026] The adaptation is therefore carried out in particular after vehicle operation, when the vehicle is stopped. The preferred configuration here as a closed hydraulic system, in particular with pressure build-up and pressure reduction via a valve acting in both directions using a pressure supply unit, has the great advantage that, by means of suitable sensors, non-linear relationships can be represented via characteristic maps (e.g. pressure-volume characteristic curves, the relationship between motor current and braking pressure, the relationship between braking pressure and / or deceleration when wheel brakes are heated). It should be noted that the characteristic maps here can be adapted during operation using environmental influences, for example the detection of air in the system or heating of the wheel brakes.

[0027] If the non-linear relationship is mapped to a mathematical function or characteristic map, automatic adaptation of the electro-hydraulic braking system also becomes feasible.

[0028] Once the AI ​​approach is consistently realized in hydraulic brake system (EHB), the advantage of electromechanical brake (EMB) being easily closed-loop controllable or open-loop controllable will disappear, and the advantage of low manufacturing cost of hydraulic brake system will be more effective, because the disadvantage in application cost will be greatly reduced.

[0029] Furthermore, different solution approaches should be examined depending on the electric drive architecture and level of autonomy. Thus, for the electric traction motor arrangement shown in FIG. 1b, the following different architectures are examined: a) Electric traction motors TM1, TM2 on the rear axle HA or the front axle VA; b) electric traction motor TM1 on the rear axle HA and electric traction motor TM3 on the front axle VA; c) two electric traction motors TM1, TM2 on the rear axle HA for individual torque control of the two wheels R1, R2; and d) two electric traction motors TM1, TM2 on the rear axle HA and one electric traction motor TM3 on the front axle VA; A solution for is described.

[0030] The variants a) to d) can be combined in any way, whereby the most effective solutions b) and c) are prerequisites for further developments according to the invention.

[0031] In addition to the E-drive module, the following configurations of the brake unit shown in Figure 2c are also supported: a) Central electrohydraulic brake (EHB-Z) with individual braking torque control means per wheel for the four wheel brakes (R1, R2, R3, R4) via solenoid valves; b) an axle module with electrohydraulic brakes (EHB-VA) with individual braking torque control means for each wheel for the two wheels (R1, R2) of the front axle (VA), optionally combined with hydraulic lines to the two wheel brakes (R3, R4) of the rear axle (HA) (see for example Figures 6b and 6c, which are explained in more detail below); c) an axle module with electrohydraulic brakes (EHB1, EHB2) for each of two wheels (R1, R2; R3, R4) of an axle (VA, HA) with individual braking torque control for each wheel via solenoid valves; and d) Wheel modules with electromechanical brakes (EMB1 to EMB4) for each wheel (R1, R2, R3, R4) of the vehicle It is advisable to check the following.

[0032] Furthermore, the various requirements of SAE Levels 2 to 5 for autonomous driving in the configuration of the embodiment should also be taken into account. In the solution approach, a distinction is made between whether a fail-safe solution is required only for SAE Level 2 or whether a fail-operational solution is required for SAE Levels 3 to 5.

[0033] [Table 1]

[0034] From the above-mentioned priorities, further from the time delay in case of driver intervention during the duration and speed of the autonomous driving mode (SAE Levels 3-4) and the resulting liability liability of the vehicle manufacturer, the following main requirements are defined:

[0035] [Table 2]

[0036] The object of the present invention is achieved by a driving dynamics system FDS, a vehicle equipped with a driving dynamics system and a method for operating a driving dynamics system as set forth in the respective independent claims. Advantageous configurations and developments of the invention are set forth in the respective dependent claims.

[0037] The driving dynamics system for a vehicle includes, in particular, at least one wheel brake for dissipatively braking a wheel of the vehicle and at least one brake unit assigned to the at least one wheel brake and configured to generate a dissipative braking torque with the at least one wheel brake. The driving dynamics system further includes at least one electric traction motor that can be controlled to generate a regenerative braking torque for at least one wheel or axle of the vehicle. The driving dynamics system further includes a central control unit configured to control the at least one brake unit and the at least one electric traction motor in combination with each other for a braking function, such that a combined braking torque can be generated with the at least one brake unit and the at least one electric traction motor. Here, the braking function relates to a control case for open-loop and / or closed-loop control of a basic braking torque and a closed-loop controlled additional braking torque at the same time. Here, as an option, the basic braking torque is formed by at least one brake unit and the closed-loop controlled additional braking torque is formed by at least one electric traction motor, or the basic braking torque is formed by at least one electric traction motor and the closed-loop controlled additional braking torque is formed by at least one brake unit, or at least one brake unit and at least one electric traction motor together form the basic braking torque and the closed-loop controlled additional braking torque, respectively.

[0038] In one configuration of the invention, the braking functions include the following functions: -Automated Emergency Brake (AEB) with full braking torque distribution to the rear and front axles, specifically EBV closed-loop control, specifically EBV closed-loop control on the rear and front axles of the vehicle; -Anti-lock braking system (ABS) with basic braking torque assistance, in particular via at least one traction motor (TM1, TM2, TM3, TM4); -Electronic Stability Program (ESP); -Electric Brake Force Distribution (EBV); -Anti-Slip Control (ASR); -Automated Cruise Control (ACC); -Recuperation management, especially for individual axle or wheel-specific recuperation; - Base brake with heat management; - Yaw moment closed-loop control in case of failure of wheel brakes (RB1, RB2, RB3, RB4); and / or - Yaw moment intervention control for steering assistance, At least one of, and preferably a plurality of, the following is selected:

[0039] In particular, the central control unit comprises a central computer, which in this case preferably comprises redundant microcontrollers μCI, μC2, μC3 and / or a large memory, in particular of the order of gigabytes.

[0040] In another configuration of the driving dynamics system, the brake unit comprises an electric motor drive and is configured as an electrohydraulic or electromechanical brake unit.

[0041] In one further development, the brake unit is configured as an electrohydraulic brake unit with a pressure supply unit driven by an electric motor, a valve arrangement is provided between the pressure supply unit and at least one wheel brake or wheel brakes of an axle, the valve arrangement includes a pull-proof wheel valve and / or a circuit isolation valve, in the event of a leak in at least one wheel brake, the valve arrangement is configured to isolate the respective wheel brake by closing it, and the central control unit is configured to drive the at least one brake unit and / or the at least one electric traction motor in such a way that a braking torque control is performed at the further wheels of the vehicle, in particular at least three wheels. In this case, in particular, the wheel brakes of an axle of the vehicle, in particular the wheel brakes of the front axle, can be isolated by the valve arrangement.

[0042] In one development, the central control unit is coupled to at least one brake unit control of the brake units.

[0043] In another configuration, the central control unit is configured for transmitting a target signal to an engine controller of at least one traction motor and to a brake unit controller of at least one brake unit in a braking function.

[0044] In one configuration, the central control unit is further configured to drive and control the at least one electric traction motor for regenerative braking of the vehicle when the speed of the vehicle being braked is above 80 km / h during normal driving, and during regenerative braking, an electric brake force distribution (EBV function) is realized simultaneously on the front and rear axles of the vehicle, in particular where 20% to 40% of the total braking torque acts on the rear axle of the vehicle and 60% to 80% of the total braking torque acts on the front axle of the vehicle.

[0045] In one further development, the wheel brakes of the wheels of the vehicle are assigned their own brake units, in which case the brake units are in particular constructed electromechanically, in which case in particular for each of the two wheels the brake unit associated with the wheel brake and an electric traction motor are integrated into a wheel module.

[0046] In one embodiment, a common brake unit is assigned to the wheel brakes of two wheels of an axle of the vehicle, in particular where the brake unit is designed electrohydraulic, in particular where a first brake unit is assigned to the two wheels of the rear axle and a second brake unit is assigned to the two wheels of the front axle.

[0047] In this case, a central brake unit is assigned to the wheel brakes of the four wheels of the vehicle, which in particular is of electrohydraulic design.

[0048] In one embodiment, a common brake unit is assigned to the wheel brakes of two wheels of a first axle, in particular the front axle, of the vehicle. In this case, in particular the brake unit is configured electrohydraulic. In particular, in the wheel brakes of the first axle, a wheel-individual dissipative braking torque can be adjusted in a hydraulic line between the brake unit and the wheel brakes, in particular by means of solenoid valves. In particular the brake unit can further be connected via a hydraulic line to the wheel brakes of two wheels of a second axle, in particular the rear axle. In this case, in particular, in the wheel brakes of the second axle, a common dissipative braking torque that is not wheel-individual can be adjusted.

[0049] In one configuration, a first electric traction motor is assigned to a first pair of two wheels on a first axle, in particular a rear axle of the vehicle, and a second electric traction motor is assigned to a second pair of wheels on a second axle, in particular a front axle of the vehicle.

[0050] In one configuration, a first wheel and a second wheel of a first axle, in particular a rear axle of the vehicle, are each assigned a dedicated electric traction motor.

[0051] In one further development, the first wheel and the second wheel are each further assigned their own brake units, in particular the respective brake units being of electromechanical design, in which in particular for the first wheel and the second wheel, the respectively assigned electric traction motor and the respectively assigned brake unit are integrated in a respective wheel module assigned to the first wheel and to the second wheel.

[0052] In another embodiment, a third electric traction motor is furthermore commonly assigned to the third and fourth wheels of the second axle, in particular the front axle of the vehicle. In this case, in particular, a common brake unit is assigned to the third and fourth wheels. In this case, in particular, the common brake unit is electrohydraulic. In this case, in particular, the third electric traction motor and the common brake unit are integrated in an axle module assigned to the second axle, or in particular, a central brake module, in particular electrohydraulic, is provided, by means of which wheel-specific braking torques can be generated for the first and second wheels and a common braking torque can be generated for the third and fourth wheels.

[0053] In one configuration, the central control unit is configured to distribute the basic braking torque and the closed-loop controlled additional braking torque to at least one brake unit and at least one electric traction motor as a function of the vehicle deceleration and / or as a function of the friction value of the road. Here, in particular when the deceleration and / or the friction value are relatively low, for example in the case of ABS control on snow or ice or deceleration in an ACC braking operation, the electric motor brake unit and / or the at least one electric traction motor generate the closed-loop controlled additional braking torque. Here, in particular when the deceleration and / or the friction value are relatively high, for example when braking on asphalt, the electrohydraulic brake unit generates the closed-loop controlled additional braking torque. Here, in particular when the deceleration and / or the friction value are medium, the brake unit or the traction motor generates the basic braking torque as a constant braking torque and the other brake unit or the other traction motor generates the closed-loop controlled additional braking torque.

[0054] In one development, the central control unit is configured to perform EBV control during automatic emergency braking, taking into account the braking torque gradients of the at least one brake unit and the at least one electric traction motor such that a maximum braking torque is simultaneously achieved at the front and rear axles, respectively, of the vehicle, in particular before the wheels lock.

[0055] In one development, during regenerative braking, in particular when the vehicle battery is in a fully charged state, the following strategy is used: -Feedback of regenerated energy to the battery up to the limit of power consumption; - Field-oriented control (Id / Iq current control) of electric traction motors so that the energy is dissipated inside the motor; - dissipating the energy gained from the generator operation of the electric traction motor, supplying the energy gained for the electric consumers of the vehicle, and / or heating a fluid reservoir for use in a heat pump for cooling or heating; and / or - using an intermediate storage device, preferably electrical, designed for pulsed output, such as a supercapacitor or a flywheel storage; At least one of these is used.

[0056] In one development, at least one electric traction motor with an inverter, which switches the windings of the at least one electric traction motor in a series or parallel circuit, is driven by three strands of the excitation coil of the brushless electric motor, in particular in this case a four-quadrant operation is possible with the inverter, i.e. with quadrant 1 with a positive rotation speed and positive torque of the electric motor, quadrant 2 with a positive rotation speed and negative torque of the electric motor, quadrant 3 with a negative rotation speed and positive torque of the electric motor and quadrant 4 with a negative rotation speed and negative torque of the electric motor.

[0057] In one configuration, the central control unit is configured to perform brake control based on a characteristic map, in particular the characteristic map mapping a pressure-volume characteristic curve, a relationship between motor current and brake pressure and / or a relationship between brake pressure and / or deceleration upon heating of the wheel brakes.

[0058] In another configuration, the central control unit is configured to detect sensor data during operation of the vehicle, in particular in a state after the start of operation of the vehicle, for example during a driving operation or in a stationary state before or after a driving operation, and to adapt the control of the braking function based on the detected sensor data using an artificial intelligence process, in particular machine learning or a neural network. In this case, in particular, the artificial intelligence process can be executed by a computer of the central control unit. In particular, the adaptation is executed in a safe state of the vehicle, in particular in a parked state of the vehicle. In this case, in particular, a characteristic map is determined based on the detected sensor data, which represents, for example, a pressure-volume characteristic curve, a relationship between the motor current and the braking pressure, and / or a relationship between the braking pressure and / or the deceleration when the wheel brakes heat up. Here, in particular, the characteristic map can be adapted based on the sensor data and the artificial intelligence process if a deviation from the current characteristic map is identified, for example due to environmental influences, air in the system or heating of the wheel brakes.

[0059] Another driving dynamics system for a vehicle comprises at least one electric traction motor controllable to generate a regenerative braking torque for at least one wheel or axle of the vehicle, and a central control unit configured to control the at least one electric traction motor for a braking function, where the central control unit is configured to control the at least one electric traction motor to generate a regenerative braking torque for at least one wheel or axle of the vehicle, and to generate a regenerative braking torque for at least one wheel or axle of the vehicle, and where the central control unit is ... to generate a regenerative braking torque for at least one wheel or axle of the vehicle, and to generate a regenerative braking torque for at least one wheel or axle of the vehicle, and 2 In particular, the central control unit is configured to execute the braking function with a deceleration of less than 1 / 2. In this case, in particular, the central control unit is configured to execute the braking function by at least one traction motor of at least one axle of the vehicle, in particular by two traction motors of a rear axle of the vehicle.

[0060] A vehicle according to the present invention includes a driving dynamics system as described herein or in the appended claims.

[0061] A method for operating a driving dynamics system comprising at least one brake unit for generating a dissipative braking torque, at least one electric traction motor for generating a regenerative braking torque for at least one wheel or axle of a vehicle, and a central control unit for controlling the at least one brake unit and the at least one electric traction motor for a braking function, wherein a combined braking torque is generated by means of the at least one brake unit and the at least one electric traction motor, the braking function relating to a control case with simultaneous open-loop and / or closed-loop control of a basic braking torque and a closed-loop controlled additional braking torque. In this case, as an option, at least one brake unit is controlled to generate a base braking torque and at least one electric traction motor is controlled to generate a closed-loop controlled additional braking torque, or at least one electric traction motor is controlled to generate a base braking torque and at least one brake unit is controlled to generate a closed-loop controlled additional braking torque, or at least one brake unit and at least one electric traction motor are controlled to together generate a base braking torque and a closed-loop controlled additional braking torque, respectively.

[0062] At least one electric traction motor for driving and braking the axles or wheels of a vehicle has in particular a slave control at one or more axles or wheels of the vehicle.

[0063] The at least one brake unit or brake system is designed in particular for multiple wheel brakes, multiple electrohydraulic brake modules or multiple electromechanical brake modules.

[0064] Here, for example, the control unit can be provided with a central vehicle model, which can calculate the braking demands on the wheel modules or axle modules taking into account the friction values ​​of the road, the vehicle speed and the weight distribution during the braking process.

[0065] Furthermore, the brake control model and characteristic map for the synchronized braking torque control of the at least one traction motor and brake unit, in particular EBS or EMB, can be configured in the sense that the at least one electric traction motor or brake unit, in particular EBS or EMB, forms a basic braking torque, while a dynamic braking torque control is performed by the at least one electric traction motor and brake unit, in particular EBS or EMB, together, in particular by means of an additional braking torque formed thereby.

[0066] Furthermore, sensor data from sensors that are important for the implemented core functions and are read into the central control unit can be used, for example from wheel speed sensors for the ABS function, yaw moment sensors for the ESP function, acceleration and / or weight sensors for the EBV function and in particular for compensating the functional relationship between the vehicle's braking pressure / torque and the vehicle deceleration, which depends on the brake disc temperature, and / or sensors for an electric recuperation strategy or an emergency braking function (AEB) can be provided.

[0067] The central driving dynamics system can be used, for example, so that the use of at least one brake unit is optimized in terms of maximizing recuperation and maximizing braking or brake control power in each different driving situation, in particular depending on the braking situation, for example comfort braking or emergency braking, and also depending on the road conditions, for example braking on asphalt, on snow or on ice, so-called μ-jumps or μ-splits, and also depending on the availability of the brake unit. In particular, the intelligent closed-loop control via the driving dynamics system can reduce the cost of the brake calipers, in particular by minimizing the thermal load of the friction brakes, in particular by downsizing and / or selecting the appropriate type of friction brake used, for example drum brakes or disc brakes.

[0068] Thus, already in the first "architecture I" via a central control unit as brake unit, a hydraulic brake system in each case for each wheel of the front and rear axle (EHB-Z) or a hydraulic brake system only for the front axle (EHB-VA) can be controlled together with at least one electric traction motor. In architecture I, a control unit (M-ECU) is provided for each brake unit EHB-Z or EHB-VA and at least one electric traction motor of each axle. BM , S-ECU TM,HA , S-ECU TM,VA ) are provided, and these control devices have interfaces to the central control unit M-ECU. DOMAENE The control unit (M-ECU) transmits a target signal, which is in particular a target braking torque or contains a target braking torque, to the control unit (M-ECU) BM , S-ECU TM,HA , S-ECU TM,VA ) and send it out.

[0069] With such an architecture, a great potential for SAE Level 2 brake systems including fail-safe operation can already be exploited without modifying the installed brake equipment. Such a brake equipment can be, for example, a current one-box brake equipment available on the market, for example as described in DE 102018212905 A1, DE 102019204016 A1 or DE 102019122169 A1. For this, no modification of the mechanical or hydraulic structure of the brake equipment is necessary, only an extension via an interface, for example via an individual target pressure interface for each wheel or an individual target torque interface for each wheel, is necessary. This is achieved by integration into a central control unit (domain) and an intelligent drive control of the brake unit and of the electric traction motors which are installed on one or both of the vehicle axles or on two wheels of the vehicle axle.

[0070] Advantageously, instead of the above-mentioned current brake system, the brake unit (EHB) is further optimized in such a way that it is configured only as an individual pressure regulator for each wheel with a wheel control valve. Each hydraulically actuated wheel brake then forms a separate wheel circuit and is preferably connected to a pull-resistant wheel valve MV 2k The wheel circuits can be advantageously separated via closure of the brake line. Furthermore, the brake unit can be provided with an EHB pressure regulator with a control valve only for the front axle (EHB-1, EHB-VA) and / or a pressure regulator with a control valve for the rear axle (EHB-2) and / or a pressure regulator with additionally a brake circuit for the two wheels of the rear axle (EHB-Z). In the above-mentioned solutions EHB-1 and EHB-2, the "architecture II" is applied, which is explained in the following sections and figures.

[0071] In the embodiment for SAE Level 4, the driver's request is no longer detected by an operating unit for detecting the driver's request as in the conventional case, but rather preferably by a piston-cylinder unit with a piston and a hydraulic chamber and a hydraulic connection to the brake circuit or via the E-pedal. In this case, the driver's request signal is redundantly transmitted to the M-ECU. DOMAENE The E-pedal is read into the brake system. With SAE level 5, a pedal is no longer necessary. The modular construction with E-pedal has the decisive advantage over the prior art that SAE levels 4 and 5 can be covered by the module and that the omission of the hydraulic connection between the operating unit and the pressure regulator allows a particularly high flexibility in terms of accommodating the pressure regulator in the vehicle. Furthermore, a noise source is avoided, since the hydraulic modulation noise occurs far from the bulkhead and therefore no structure-borne sound transmission into the passenger compartment occurs. An embodiment of such an electrohydraulic braking system is explained in more detail with the aid of FIGS. 6a to 6d.

[0072] Thus, the above-mentioned different embodiments of the brake unit (EHB) and architectures I-II are made possible by a central vehicle model which realises functions (a)-(g).

[0073] The first advantageous function (a) the basic braking function, is achieved by using at least one electric motor primarily for braking, Friction brake heating is minimizedIf a brake system with a fade strategy according to the prior art (see, for example, FIG. 1b) is designed, the maximum pressure in the AMS fade test is taken as the basis for dimensioning (see “Bremsenhandbuch”, 5.Auflage, Kap.6.3.2., Abbildung 6.11). For the AMS test, ten follow-up brakings from 100 km / h are simulated. This results in the wheel brakes of the front axle being heated to 600 °C and those of the rear axle to approximately 500 °C. In this case, the pedal force in a standard vacuum brake booster increases by approximately 80%. This means that the brake system must be designed for a fade case with a pressure 80% higher than the normal locking pressure. With a corresponding safety reserve, the brake system is therefore typically designed for a maximum pressure of approximately 200 bar to 220 bar. With typical fade strategies, regenerative braking is not possible at relatively high speeds above 60 km / h ("Bremsenhandbuch", Kap. 19.3.2., Abbildung 19.12), so that the braking power potential of the electric motor is not fully utilized. This limitation of regenerative braking to the speed range below 60 km / h is due, on the one hand, to the limited volume absorption by the storage chamber of the ESP unit, for example in two-box brake systems with an electronic follow-up brake booster. On the other hand, it is a matter of liability for damages of the brake manufacturer and legal restrictions on the extension of regenerative braking operation. The limitation here is due to the limited absorption capacity of the battery in terms of energy, especially in the fully charged state.

[0074] With central FDS control, the capacity of regenerative braking can be exploited. Furthermore, the heating of the friction brakes and thus the fade effect can be significantly reduced, since the braking energy no longer leads to significant heating of the friction brakes. For example, at least one electric traction motor can be operated with an inverter capable of performing a four-quadrant operation (quadrant 1: positive motor speed, positive motor torque; quadrant 2: positive motor speed, negative motor torque; quadrant 3: negative motor speed, positive motor torque; quadrant 4: negative motor speed, negative motor torque). In this case, an electric traction motor with a drive power of 130 kW as an example can be braked with a torque of 250 Nm at the rear axle of a medium-sized vehicle (see BMW's i3 vehicle with a maximum braking torque of 2000 Nm / s at the rear wheels and 3000 Nm at the front wheels) in the second quadrant with approximately the same torque and power. Here, the braking torque in generator operation of the electric traction motor is somewhat higher than the drive braking torque of the electric traction motor, since the losses in the motor and the transmission also have a braking effect, while the losses here reduce the drive torque during acceleration. In this way, with such a design, already at a speed of 100 km / h, about 60% to 70% of the braking energy at the rear axle is obtained by regenerative braking. If such a motor is also installed on the front axle, a deceleration of about 50% can also be achieved on the front axle. Here, one or more energy management strategies are pursued when braking via the electric traction motor, whereby an efficient selection or combination of strategies sets a limit for braking via the electric traction motor, i.e., practically only the torque limit in the four-quadrant operation of the inverter.

[0075] Four basic strategies for energy management are available: (1) Feedback to the battery up to the limit of power consumption, which depends among other things on the battery's energy absorption capacity, in particular on the battery's current state of charge (SOC). (2) Implementing a field-oriented control (Id / Iq current control) of the electric motor so that the energy in the electric traction motor is dissipated internally. The internal energy dissipation is limited by the resistance and eddy current losses of the excitation winding of the stator of the electric traction motor and by the motor cooling means. Since the electric traction motor is provided with water or oil cooling and the heating during the pulse load during the braking process (which is usually completed in 5 to 10 seconds during full braking) is damped by the large thermal mass of the electric motor, the absorption of energy during pulse operation by the electric motor is rather non-critical and can therefore usually be fully utilized.

[0076] Furthermore, the cooling circuit of the electric traction motor can be led to a water reservoir which can then be used for particularly efficient cooling and heating of the vehicle interior by means of a heat pump, so that the energy "lost" in the traction motor can be utilized, in particular with a heat pump efficiency of more than 300%. (3) As a third option, the energy generated by the electric traction motor in generator operation can be used via a wear-free eddy current brake known from a motor test bench or can be used to heat another medium (e.g. water) equivalent to a boiler. The generated heat can also advantageously be used via a heat exchanger for a particularly efficient cooling or heating of the vehicle. The energy of the electric traction motor or motors is preferably guided to a heat sink. (4) As a fourth option, an electrical intermediate storage device may be provided that is designed for pulsed power, for example for supercapacitors or flywheel storage. Supercapacitors or flywheel storage are particularly well suited for pulsed power and can absorb significantly higher peak powers compared to batteries. The energy stored for a short time in the supercapacitors or flywheel storage can be used during acceleration of the vehicle after a braking process or can be utilized in the vehicle in other ways.

[0077] Regenerative braking management with energy management allows the heating of the friction brakes in the AMS test to be reduced by more than 50%, and even in particular by 70% to 80%. This effect can be advantageously used to simplify the friction brakes on the front axle and at the same time use inexpensive drum brakes with advantageously low weight on the rear axle. Alternatively, the effect can be used to design hydraulic brakes to significantly lower maximum braking pressures, for example 120 bar to 140 bar instead of 200 bar to 220 bar, which has an advantageous effect on the costs of the brake system, since the pressure supply can be equipped with a comparatively smaller electric motor. Furthermore, the hydraulic volume of the pressure supply unit can be reduced.

[0078] Furthermore, by appropriately configuring the interface between the driving dynamics system and the brake system together with the use of the control of the electronic brake force distribution (EBV function) in the advantageous second function (b), the dynamics of the automatic emergency braking (AEB) can be further increased, which has a significant influence on the braking distance, especially at high speeds. If braking is performed via the electric motor, the driving dynamics system must meet the legal requirements and guarantee the vehicle safety, so that driving stability (see priority 2 above) and steerability (see priority 3 above) are obtained. That is, for example, the rear axle must not lock before the front axle, and in particular the ABS must be activated when the wheels of the front axle lock. The interface between the driving dynamics system and the brake system must therefore be configured in such a way that the maximum braking torques (wheel lock limits) on the front and rear axles are reached approximately simultaneously, and preferably used for controlling the EBV function. This allows the time from the start of braking to maximum deceleration (TTL time) of 140 ms to be reduced to 90 ms already for electric traction motors with a moderate power of 130 kW on the front and rear axles of a medium-sized vehicle, as will be explained below with reference to FIG. 4. At speeds above 100 km / h, a reduction in braking distance of several meters can be achieved by the above measures. If a reduction in the TTL time is not feasible, for example due to chassis limitations, braking action by an electric motor can be advantageously used instead in order to make the brake system cheaper and more compact. That is to say, the pressure supply of the brake unit can be driven by a motor with a lower torque and / or by a motor with a weaker power, possibly even by a low-cost brush motor.

[0079] In the third advantageous function (c), axle-specific recuperation via an electric motor can be realized. Here too, the access from the driving dynamics system to the solenoid valves of the brake unit (EHB) or a suitable interface to the brake unit (EHB) must be defined so that the ABS operating state intervenes in critical error cases. In the case of cooperation between the brake unit (EHB) and an electric traction motor that is controlled via the driving dynamics system, the pressure build-up and pressure reduction via the inlet or separating valve to the brake circuit of the front axle must be controlled accordingly for fade. This can be done, for example, via PWM control of the inlet valve for the pressure build-up, and alternatively via a MUX method via the inlet or separating valve for the pressure reduction, or via a pressure reduction with the outlet valve.

[0080] The solution in the brake units EHB-Z and EHB-VA is simpler and much more flexible, as will be explained below with reference to FIGS. 6a to 6d, in particular if the wheel inlet valves are designed for a bidirectional volumetric flow with pull-in resistance and solenoid valves MV 100 , MV 200 , MV 300 , MV 400 , MV 500 , MV 600 , MV 700 , MV 800 , MV 900 , MV 1000 , MV 1100 , MV 1200 , MV 1300 , MV 1400 , MV 1500 , MV 1600 , MV 1700 , MV 1800 , MV 2000 , MV 2100 , MV 2200 , MV 2300 , MV 2400 , MV 2500 , MV 2600 , MV 2700 , MV 2800 , MV 3900 , MV 400 , MV 500 , MV 6100 , MV 2900 , MV 3800 , MV 400 , MV 500 , MV 620 , MV 400 , MV 500 , MV 630 , MV 400 , MV 500 , MV 640 , MV 400 , MV 500 , MV 650 , MV 400 , MV 500 , MV 660 , MV 400 , MV 500 , MV 670 , MV 400 , MV 2k (hereinafter also referred to as inlet / outlet valves). Whereas in the embodiment of the EHB according to FIG. 9a or in the variants according to FIGS. 6a to 6d in which no or only a few outlet valves are provided at the wheel brakes, the pressure reduction takes place exclusively via the inlet / outlet valves, in the embodiments according to FIGS. 6a to 6d and 9b there is a freedom of braking torque reduction via the inlet / outlet valves or via the outlet valves. This is advantageous in realizing a highly dynamic braking torque intervention. In the embodiment according to FIG. 6b, the recuperation strategy individual for each axle is hardly impaired either. This is because the pressure reduction can be selectively performed via the inlet / outlet valves MV 2k,1-4or via the outlet valves AV1-AV4. In a recuperation strategy via the driving dynamics system, the braking torque characteristics of the electric traction motor and the brake unit (EHB) can be synchronized so that recuperation is maximized. If recuperation via the electric traction motor is limited, for example in a fully charged state of the battery, kinetic energy is dissipated via the brake unit (EHB). If the battery allows the supply of power, recuperation is mainly performed via the electric traction motor. Thus, due to the individual degrees of freedom for each wheel, recuperation per axle with X-braking force distribution can also be easily realized.

[0081] In the case of the embodiment as an axle pressure regulator (EHB-1, EHB-2) preferably having the structure according to Figure 9a and Figure 9b, the recuperation strategy is very simple and no valve check is required, since the braking torque increase and braking torque reduction can be performed very accurately by the known PPC pressure closed loop control or pressure open loop control.

[0082] In the fourth advantageous function (d), at least one electric traction motor can form the basic braking torque in a closed-loop control operation. This is made possible by using modern electric high-power and high-torque traction motors (>200 Nm, <100 kW) and operating at high operating voltages (400 V, in particular 700 V to 900 V). Such a traction motor can perform highly dynamic braking torque changes (typical value: 15000 Nm / s, achievable values ​​are 30000 Nm / s), which can be operated in four-quadrant operation and are very dynamic in braking torque increase and braking torque reduction. In the case of low target braking torques, this is more dynamic than a hydraulic brake unit (EHB). Depending on which torque is available over the entire speed range (from 1000 Nm in FIG. 3 to the maximum vehicle speed), the maximum pressure of the brake unit (EHB) can be reduced by the maximum torque. After the new ASR control made possible by the electric traction motor (see ATZ 2 / 2014: “Regelalgorithmen für Rekuperation und Traktion bei Electrofahrzeugen”), higher pressures are no longer required for the ASR control compared to the previous prior art, so that the maximum pressure of the brake unit (EHB) is normally determined by the braking action.

[0083] In an advantageous fifth function (e), at least one electric traction motor can be used as an aid in the event of a brake unit (EHB) error. A relatively new one-box brake system, as shown for example in DE 10 2018 212 905 A1, can achieve a braking force of 0.3 m / s in the event of a failure of the pressure supply by the driver's foot force. 2 The deceleration rate is only 0.244m / s 2This meets the legal requirements of ECE-13H with a minimum deceleration of 0.58 m / s2 in case of an error, through the use of the braking force of the electric drive motor, if an electric brake unit (EHB) is integrated into the driving dynamics system, as proposed for example in WO 2020 / 165255. 2 Braking forces of up to 10 ...

[0084] If the brake system shown in WO 2020 / 165255 is further developed such that the electric drive motor according to function (d) generates the basic braking torque and the pressure supply is also partially redundant by means of a redundant winding, for example by configuring the pressure supply with 2×3 phases and (partially) redundant electronics (DV1-ECU1, DV-ECU2) and two vehicle power grids and / or energy supplies (BN1, BN2) as well as connection terminals to the data lines (DS1, DS2), the pressure supply can be operated with 1 / 2 the power or 1 / 2 the torque even in the case of frequent failures of the EC motor due to failure of a winding or a power semiconductor or a winding of the motor output stage. Thus, in the preferred design of 140 bar to 160 bar, a pressure of 70 bar to 80 bar can still be generated. In this way, full ABS control is possible even in error cases in the event of a partial failure of the pressure supply. If at least one traction motor is furthermore used for setting the basic braking torque in order to form a basic braking torque in such an error case, ABS operation at maximum deceleration, in particular at about 1 g to 1.4 g, can also be achieved.

[0085] If, for example, in a one-box brake system as described in WO 2020 / 165255, two brake fluid flow directions, i.e. from the pressure supply to the wheel brake and from the wheel brake to the pressure supply, are used in a pull-resistant manner as inlet / outlet solenoid valves or changeover solenoid valves (SV1-SV4 in FIG. 7 of WO 2020 / 165255) designed for a bidirectional volume flow between the pressure supply and the wheel brake, each wheel circuit can be reliably diagnosed and isolated from the brake system in the event of an error. This is not possible with the wheel inlet valves used in the prior art in other cases, because non-diagnosable and non-reliably closing check valves (e.g. 50a, 50b in FIG. 1 of DE 102013222281 A1) are used in parallel to the inlet valves (e.g. 6a-6d in FIG. 1 of DE 102013222281 A1). This allows the driving dynamics system to operate with a three-channel wheel pressure control, which allows vehicle stabilization functions equivalent to, for example, an ESP function and pressure maintenance in the wheel brake circuits even in error cases. This also gives an additional degree of freedom for braking torque control, especially in the case of individual regeneration for each wheel. Novel changeover valves of this type are preferably also used in the EHB solutions according to the invention of Figures 6a-6d and 9a-9b, which are described in more detail below.

[0086] In both cases, to ensure steerability according to priority 3, the front axle can be equipped with a dual-channel ABS function, which is provided by a pull-resistant valve (switching solenoid valve MV 2k) is not provided. In this case, a separation valve is provided between the front and rear axles. Pressure control can alternatively be performed in this case via a MUX pressure control method, with the pressure increase and pressure reduction being performed via a changeover valve, which is preferably configured such that the valve seat of the solenoid valve is connected to the wheel brake in order to ensure that no braking pressure is introduced into the wheel brake. Optionally, an outflow valve can also be provided, so that as an alternative to the MUX pressure reduction, a pressure reduction into the reservoir tank via the outflow valve takes place. See further FIG. 9a and FIG. 9b, which are explained in more detail below.

[0087] As another alternative, a standard ABS control can be implemented here, in which the preload is regulated via the pressure supply, the pressure is increased via PWM control of the changeover valve and reduced via timing of the outlet valve. Here, the valve seat is connected to the pressure supply in such a way that a proportional adjustment of the flow cross section is possible. Here, a retraction-resistant changeover valve is particularly important so that in the event of a large pressure difference, braking pressure is not introduced into the wheel brakes in the event of an error.

[0088] In the sixth advantageous function (f), a yaw moment intervention for steering assistance can be carried out using the setpoint setting of the driving dynamics system. For this purpose, the pressure build-up and pressure reduction can be correspondingly controlled in a closed loop via the inlet valve (see reference number 11 in DE 10 2018 212 905 A1), so that the hydraulic brake force is modulated by the electric brake force. For the pressure build-up, this can be carried out via PWM control of the inlet valve, and for the pressure reduction, this can alternatively be carried out by the MUX method via the inlet or separating valve or by pressure reduction via the outlet valve.

[0089] The solution with EHB-Z and EHB-VA shown in Figures 6a and 9a is simpler, especially if the wheel inlet valves are configured as inlet / outlet valves that are retraction-resistant and designed for a bidirectional volume flow, so that the pressure can be maintained on the basis of the absence of a check valve when the pressure supply has a lower pressure level than the wheel brakes and it is desired that the hydraulic braking torque be kept constant in a recuperation strategy. Furthermore, in the event of simultaneous return movements of the pistons of the piston-cylinder units of the pressure supply device, there is a freedom of increasing the braking torque via the bidirectional inlet / outlet valve or via the outlet valve into the reservoir, which is favorable for the realization of a highly dynamic braking torque intervention.

[0090] In the seventh advantageous function (g), the setpoint setting of the driving dynamics system can be used to generate individual braking torques for each wheel for individual recuperation. For this, the pressure build-up and pressure reduction must be controlled in a corresponding closed loop manner via the inlet valve (see reference number 11 in DE 10 2018 212 905 A1) so that the hydraulic brake force is modulated by the electric brake force. This can be done in the case of pressure build-up via a PWM control of the inlet valve, and in the case of pressure reduction, alternatively by the MUX method via the inlet or separating valve or by pressure reduction via the outlet valve.

[0091] In the solutions with EHB-Z and EHB-VA according to Figs. 6a, 6c and 9a-9b, which are described in more detail below, in particular the wheel inlet valves are pull-resistant inlet / outlet valves MV 2k6a-6d, the pressure reduction is exclusively via the inlet / outlet valves, whereas in the embodiment of the brake unit (EHB) according to the variant of FIG. 9a or FIG. 6a-6d, in which no or only a few wheel brakes are provided but an outlet valve is provided, the freedom of the brake torque reduction is via the inlet / outlet valves or via the outlet valves is provided in the embodiment of FIG. 6a-6d and FIG. 9b. This is particularly advantageous in realizing a very flexible brake torque intervention in the sense of maximizing the regeneration. In a regeneration strategy via the driving dynamics system, the brake torque characteristic of the at least one electric traction motor and the brake torque characteristic of the brake unit (EHB) can be synchronized in such a way that the regeneration is maximized. If the regeneration via the at least one electric traction motor is limited, for example in the full charge state of the battery, the kinetic energy is dissipated via the brake unit (EHB). When the battery is permitted to draw power, regeneration occurs primarily through the electric traction motors.

[0092] For functions (e), (f) and (g), a pull-resistant and low-cost inlet / outlet valve MV 2kis important because it allows to avoid brake circuit failure and allows the wheel circuits to continue to be driven even in the event of a changeover valve leak. In this way, the 4-channel wheel pressure control operation can be maintained even in the event of a changeover valve leak, or the 3-channel wheel pressure control operation can be used to perform emergency steering or steering assistance even in the event of a wheel circuit interruption, which simplifies the redundancy requirements of the electric power steering unit for higher levels of autonomous driving (SAE Levels 3-4). These functions (e) and (f) are particularly important for the total cost of braking and steering of the primary chassis control actuators. Here, if the electric power steering unit is configured fully redundantly, two steering actuators are required. In contrast, the brake can be used as a redundant function for the steering unit as an effective solution approach to meet the SAE requirements for levels 3-4. Furthermore, the brake has the advantage that a non-identical unit can be used for the redundant steering function, which eliminates production quality defects as a source of error in an identical steering unit. The steering function via the brake unit (EHB) can also be provided as a third fallback level of an electric power steering part EPS that is already configured redundantly with two steering actuators or as a second fallback level of an electric power steering part EPS that is configured only non-redundantly or partially redundantly, for example with a steering actuator having 2×3 phases and a redundant control device. Furthermore, the steering unit (EHB) can also assist steering on a second axle that is not provided with an EPS or perform a yaw moment intervention supplementary to the steering intervention, for example to stabilize the vehicle during μ-split braking.

[0093] Thus, with a hydraulic brake system with only one pressure supply, the above-mentioned functions also make it possible to meet the SAE requirements for automated driving level 3. In order to meet SAE levels 4 and 5, all prerequisites are likewise achieved by the inventive extension of the one-box brake system shown in Fig. 6a and Fig. 6b. If the pressure supplies are configured redundantly and, as in function (b), the electric traction motor assists in generating the braking torque, the commercially available emergency braking function with dynamics of 150 ms can also be guaranteed. This allows a TTL of 150 ms to be achieved with reasonable losses, whereas the maximum dynamics of 90 ms of the solution according to the invention cannot be achieved in normal cases. This corresponds to the output data of commercially available brake boosters.

[0094] In comparison, braking systems for SAE levels 3 and 4 (see WO2018233854) can only utilize the pressure dynamics of the ESP pump, which in the case of an error of the brake booster only allows a pressure increase of 450 ms to 50 bar according to the latest task book. In driving dynamics systems, the pressure increase via the ESP pump can also be facilitated by the braking torque formation dynamics of the electric traction motor. Depending on the performance of the electric traction motor, a TTL of about 150 ms to 250 ms can also be achieved in such a two-box brake system with a weak ESP pump. In this case, the emergency braking function in the error case has the same or almost the same value as in normal operation.

[0095] The integration of the brake system in the central control, thanks to the above-mentioned synergies and functional support, ultimately offers the possibility to omit the hydraulic fallback level by means of the brake pedal (see Fig. 6-6c) and to introduce an E-pedal or to omit the pedal altogether. Thus, a brake system with only one pressure supply in a component unit with FDS according to the invention (one-box brake system) has the full possibility of achieving AD Level 5 qualification.

[0096] The second "Architecture II" In the 2010 EV-2011, instead of a hydraulic brake device that is driven and controlled centrally via a domain, an axle module is provided. - Electric drive motor; -Electromechanical brakes (EMB) for one wheel each; - an electrohydraulic pressure regulator for each one axle with a wheel control valve for braking torque control for each of the two wheels of an axle (EHB-VA, EHB-HA); The brake module has at least two brake modules selected from:

[0097] For example, the axle module may include an electric drive motor capable of driving the wheels of the axles (VA, HA) and braking them by generator action, and one electromechanical brake unit (EMB) for each of the two wheels of each axle or one common electrohydraulic brake unit (EHB-VA, EHB-HA) for each of the two wheels of each axle (VA, HA).

[0098] In the second embodiment, unlike the first embodiment, a control device (S-ECU VA , S-ECU HA ) are provided, and each control device (S-ECU VA , S-ECU HA ) is a central control unit (M-ECU DOMAENE ), which synchronizes the drive and braking of selected brake modules of the axles. The synchronization here is particularly advantageous for the control operation, as opposed to the normal operation of the brakes, since the different deceleration times and time characteristics of the brake torque build-up and brake torque reduction are optimally coordinated with one another by the various brake modules. Furthermore, this structure also solves problems with liability for damages, since in this case the provider of the e-axle is responsible for the entire drive and braking management.

[0099] In this second embodiment, different variations are provided, namely: a) an electromechanical brake unit EMB, particularly advantageously combined with an electric traction drive for the front axle of the vehicle (see FIG. 12a); b) an electromechanical brake unit EMB, particularly advantageously for the front axle, in combination with an electrohydraulic EBS pressure regulator with wheel control valves (see FIG. 12b); c) an electric traction motor for each wheel of the axle, particularly advantageously in combination with an electrohydraulic pressure regulator EHB with wheel control valves for the rear axle (see FIG. 12c); and d) electric traction motors for the axles, generally advantageously for the front and rear axles, combined with electrohydraulic pressure regulators EHB with wheel control valves (see FIG. 12d); is possible.

[0100] The combination of an electric motor or electromechanical brake unit EMB with an electrohydraulic brake unit EHB is particularly advantageous, since it allows the advantages of the two braking torque generators to be ideally combined: a) The electrohydraulic brake unit EHB has high dynamics in pressure reduction at high braking torques and is insensitive to high braking torques, whereas the electric drive motor or electric motor brake unit EMB has a significant advantage in braking torque gradient at low braking torques. Furthermore, the design for high loads also increases the costs. b) The electrohydraulic brake unit EHB is significantly less expensive than the electric motor brake unit EMB. Compared to a pressure regulator for the rear axle with wheel control valves for the two wheel brakes, the costs for the electric motor brake EMB are approximately twice as high. An electrohydraulic pressure regulator for the front axle with wheel control valves for the two wheel brakes costs 10% more than for the rear axle, whereas the costs for the electromechanical brake EMB for the front axle are 50% more. The reason for the over-proportionate increase in costs for the electromechanical brake EMB is that a comparatively high braking torque has to be achieved for the front axle and, in addition, in luxury cars or SUVs, two motors per wheel are required. c) By combining the electrohydraulic brake unit EHB in the configuration as a pressure regulator with the PPC-Gen2 pressure control method described below with an electric traction motor or an electromechanical brake unit EMB, the advantages of the new PPC-Gen2 pressure control method can be offset by a very precise braking torque regulation. For example, the dead times in the PPC-Gen2 process due to the partial multiplex pressure control action can be compensated by control via the traction motor or EMB, because such brake units can achieve a sufficiently comparable braking torque gradient.

[0101] The achievable pressure torque gradients are further developed using high performance electric traction motors and typical braking torque gradients using EMB, EHB and PPC-Gen2 operation with AV / EV technologies to demonstrate the advantages in Figures 13a and 13b, which will be described in more detail below.

[0102] As hydraulic basis the embodiment of figures 9a and 9b is used which will be explained in detail below.

[0103] All functions (a) to (g) performed in "Architecture I" can also be performed in "Architecture II", and even more so with greater freedom, since, moreover, a pressure supply with two pressure control valves is provided for each axle, which is preferably configured redundantly.

[0104] In the third "architecture III", the conventional electrohydraulic EHB brake system is replaced by wheel modules, where an electric traction motor and an electromechanical brake EMB are provided for each wheel module. Wheel modules with electric traction motors allow for a great deal of flexibility in the configuration of the platform. Such a concept is flexible to the maximum extent and has a greater redundancy than conventional brake systems, since in the event of a failure case in one wheel module, the remaining wheel modules can still perform all core functions of braking and brake control, vehicle stabilization and steering. The disadvantage is the high costs due to the need for an electric traction drive and an electromechanical brake unit EMB for each wheel. Furthermore, the electrical components are located in the area of ​​the unsprung masses and are therefore exposed to high mechanical loads. Advantageously, the EMBs are co-mapped with the parking brake function, thus reducing costs.

[0105] As explained in the first embodiment, it is advantageous to use the electric traction motor and the electromechanical brake unit EMB in a synchronized manner via the vehicle dynamics system, particularly when the braking power is split in the basic braking function (see in particular function (a) of "Architecture I"), so that the friction brakes can be heated up to prevent or reduce fade effects, and in the emergency braking function AEB the braking torques of the traction motor and the electromechanical brake unit EMB can be summed (see function (b) of the first embodiment "Architecture I").

[0106] Furthermore, in contrast to function (g) of "architecture I", individual regeneration for each wheel can be realized more easily. Individual regeneration for each axle (function (c) of "architecture I") can of course also be mapped.

[0107] Of importance is the application of function (f), in which during the control operation the basic braking torque is formed via the traction motor and the braking torque in the control is adjusted by means of the electromechanical brake unit EMB. Alternatively, the basic braking torque can be formed via the electromechanical brake unit EMB and the braking torque can be modeled via the electric traction motor. In the case of critical driving situations (e.g. μ-jumps), the common braking torque can furthermore be increased or reduced simultaneously by the electromechanical brake unit EMB and the electric traction motor, which in total provides a highly dynamic braking torque adaptation. A control unit (M-ECU) controls the synchronized braking torque control of the EMB and the electric traction motor for each wheel. Rad1 , M-ECU Rad2 , M-ECU Rad3 , M-ECU Rad4 ), common control of the braking torque is easily possible. This also minimizes the time delay when the braking torque changes.

[0108] Since the technical problems of the electromechanical brake EMB arise especially at high braking torques, the advantage of a coordinated braking torque reduction is great, because the EMB tends to tighten at rather high actuation torques and the release process of the brake jaws is rather problematic and leads to high costs. These problems are considerably alleviated by the generation of the basic braking torque via the traction motor. Furthermore, the assistance function makes it possible to significantly reduce the cost of the electromechanical brake EMB, the effect of which increases disproportionately with the actuation force or braking torque. If, for example, 30% of the required basic torque is generated by the electric traction motor, the cost of the electromechanical brake EMB can be reduced by more than 30%, since the electromechanical brake EMB can be dimensioned correspondingly smaller. Based on the axle load distribution during braking (typically 60%-70% of the load is distributed to the front axle and 40%-30% of the load to the rear axle), the electric traction motor of the front axle is advantageously configured to be more powerful than the electric traction motor of the rear axle. In this way, it is possible to achieve equivalent components of the electric motor brake unit EMB on the rear and front axles, since the axle load distribution during braking is compensated for by the greater braking power of the motor at the front axle.

[0109] A driving dynamics system with wheel modules is a solution that, based on redundancy, fully meets the requirements of SAE Level 5. However, it is a niche solution for special applications from the point of view of chassis control, based on high costs (4 traction motors + 4 electromechanical brakes), and the higher costs are at odds with other advantages, e.g. flexibility in manufacturing and configuration for different vehicle concepts.

[0110] In another embodiment of the driving dynamics system, a special combination brake with hydraulic braking for the front axle is provided, with one pressure regulator (EHB-VR, EHB-VL) for each wheel of the front axle and an electromechanical brake unit as an EMB module (EMB1, EMB2) at each wheel of the rear axle, preferably with an integrated electric parking brake, for example by redundantly configuring the electronic circuits EMB1, EMB2 or by realizing a self-locking mechanism of the EMB1 and EMB2 gears, for example by using a trapezoidal spindle made of plastic. The electrohydraulic EHB-VR or EHB-VL pressure regulator can be configured as a piston-cylinder unit without wheel control valves or as a pump with a simplified pump, in particular a gear pump per pressure regulator. If a piston pump is used, e.g. the 2k pump of a standard ESP unit, at least one valve device is required for pressure reduction, whereas a gear pump takes over the function of a piston-cylinder unit and can both increase the braking torque and reduce the braking torque.

[0111] For special combined brake applications the "Architecture II" is particularly suitable, where the pressure regulators for each axle are integrated and the axle control unit S-ECU VA and S-ECU HA However, the control devices of the respective braking torque regulators are connected to the central control unit M-ECU. DOMAENEFurther architectures are also conceivable, in which the central control unit communicates with the control electronics of the wheel brake braking torque regulators (EHB-VR, EHB-VL, EMB-HL, EMB-HR) and transmits the target braking torque to the control electronics of the wheel brake braking torque regulators (EHB-VR, EHB-VL, EMB-HL, EMB-HR) and to at least one traction motor (TM1, TM2, TM3, TM4). Independent of the selected architecture, the above-mentioned functions (a) to (g) of the driving dynamics system can also be realized, again with maximum potential for cost-optimization and weight-optimization of friction brakes being obtained, for example by using drum brakes on the front axle for the electromechanical brake unit EMB and smaller disc brakes on the rear axle. It is therefore particularly advantageous to utilize the braking action of the electric traction motor on the front axle for the combined brake.

[0112] Although the special combined brake solution is certainly more complicated than a solution with an electrohydraulic brake unit EHB-1 or EHB-ZA with wheel control valves on the front axle and an electromechanical brake unit EMB on the rear axle (e.g. FIG. 6c without hydraulic connection to the rear axle), such a construction has the advantage of an additional degree of freedom in positioning the EHB-VR and EHB-VL modules close to the wheels, allowing easier scaling than in the case of an electromechanical brake unit EMB on the front axle. Moreover, this can be done without the manufacturers of pressure regulating units, especially start-ups, having to rely on the solenoid valve suppliers and the technology required for pressure control with solenoid valves that can be fixedly handled by established brake manufacturers.

[0113] Furthermore, the special combination brake can be applied just as easily as the electromechanical brake unit EMB, which allows the solution to be realized at a similarly reasonable cost if a gear pump is used instead of a piston-cylinder unit. In particular, the cost-saving potential of the driving dynamics system and functions (a)-(g) is also important in the solution, as will be explained further below for other embodiments and other architectures.

[0114] The following objectives of the present invention, with great functionality, redundancy and cost advantages, are pursued using the Driving Dynamics System Control and Special Combi-Brake of Architectures I-III:

[0115] Improved / adapted / new features electric traction motors are used in ABS operations, especially on road surfaces with low friction values ​​(snow, ice), to shorten the braking distance during controlled operations, where the large braking torque gradient of the electric traction motor is advantageous compared to known ABS systems with a storage chamber (see standard ESP systems with a slow pressure reduction into the storage chamber); - instead of known means, an electric traction motor is used for ASR operation with torque control at start-up and motor speed control with braking of the rear wheels by the electrohydraulic brake EHB; - Improved AEB emergency braking function, especially when there is a risk of an accident at high speeds, by increasing the braking torque to 100ms instead of 150ms with a corresponding reduction in the braking distance; - a combined yaw moment intervention for vehicle stabilisation or steering is carried out using the torque intervention generated by the electrohydraulic brake unit EHB with the aid of the electric traction motor and the braking torque; - combined braking interventions during control operations by the electric traction motor and the electrohydraulic brake EHB, for example in the case of dynamic changes in roadway characteristics which require a rapid pressure reduction, e.g. in the case of μ-jumps; - ABS control using the electrohydraulic brake unit EHB is carried out in a multiplex manner with torque control via an electric traction motor in order to avoid dead times in the multiplex system; - Utilizing the advantages of a closed hydraulic braking system for rapid application of the core functions ABS and ESP, and automating new software functions by enabling central over-the-air updates, e.g. software updates when transitioning from SAE Level 2 to SAE Levels 3-5; - EBV closed-loop control is performed using an electric traction motor on the rear axle and an electro-hydraulic brake EHB on the front axle; - Redundant ASR function is realized by electric traction motors or electrohydraulic brake units EHB; It is.

[0116] Cost and weight savings benefits - the use of an electric traction motor in order to reduce the thermal load of the brake calipers during multiple braking (so-called AMS fade test) and thus downsize the electrohydraulic brake system, for example to design the electrohydraulic brake unit EHB for the locking pressure and additionally for a reserve of 20% to 40%, i.e. 120 bar to 140 bar instead of 200 bar to 200 bar, and also as an option for pressures lower than the required locking pressure (60 bar to 80 bar) in the effective realization of braking via the electric traction motor, which allows for energy management even when the battery is fully charged; - the use of electric traction motors to reduce the thermal load on the brake calipers and allow the use of less expensive drum brakes on the rear axle; - Braking is mainly done by electric traction motors, which reduces dust and wear on the brake equipment; - Downsizing of the electric motor brake unit EMB, in particular by means of braking torque assistance by an electric traction motor on the front axle of the vehicle and also by means of an electric traction motor on the rear axle; - Instead of a one-box with a powerful EC motor, an electrohydraulic brake EHB with a simple 2K pump with a relatively small power output is used, in combination with a standard ESP device with TTL=500ms, with the corresponding power output of the electric traction motor at 150ms, mapping the emergency braking function; - Highly dynamic pressure increase mapping using electric traction motors allows smaller solenoid valves to be used; It is.

[0117] Redundancy Improvements - Electric traction motors are used for braking in the event of a failure or partial failure of the brake system; - Electric traction motors are used to maintain rapid emergency braking AEB with TTL=150ms even in the event of failure of the primary braking system; - Electric traction motor is used to maintain EBV function even in the event of a rear axle brake circuit failure; - Electric traction motors are used in the event of a brake circuit failure; - Electric traction motors are used in the event of ESP failure; - In the event of a steering failure, the electric traction motor is used or steering intervention assistance on the front axle with yaw moment intervention on the rear axle; - Redundant ASR function is provided by the electric traction motor or the electrohydraulic brake unit EHB; It is.

[0118] The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. [Brief description of the drawings]

[0119] [Figure 1a] FIG. 1 illustrates the fade effect in an AMS test as a basis for designing a standard brake system. [Figure 1b] FIG. 2 shows a fade strategy with regenerative braking according to the prior art without a driving dynamics system. [Figure 1c] FIG. [Figure 1d] FIG. [Figure 1e] FIG. [Diagram 2] FIG. 1 shows "Architecture I" of the driving dynamics system. [Figure 2a] FIG. 1 shows “Architecture I” of the driving dynamics system, i.e. hydraulic braking systems EHB-Z, EHB-VA combined with electric traction motors TM1, TM2, TM3. [Figure 2b] FIG. 1 shows "Architecture I" of the driving dynamics system, i.e. a hydraulic braking system combined with an electric traction motor. [Diagram 3] FIG. 1 illustrates a novel fade strategy with a driving dynamics system and powerful electric traction motor(s). [Figure 4] FIG. 13 illustrates AEB time gain with braking via electric traction motor and electrohydraulic brake unit EHB with adapted EBV function. [Diagram 5] FIG. 2 illustrates the ABS control operation by the electrohydraulic brake unit EHB and the generation of a basic braking torque by the electric traction motor. [Figure 5a] FIG. 1 shows typical ABS time characteristics including wheel speed, pressure and valve time for braking torque control using electrohydraulic brake unit EHB. [Figure 5b] FIG. 13 shows optimized ABS time characteristics including wheel speed, pressure and valve time for braking torque control by electric traction motor. [Figure 5c] FIG. 13 illustrates ABS control operation during μ-jump using an electrohydraulic brake unit EHB combined with an electric traction motor. [Figure 5d] FIG. 1 illustrates ABS control operation in the low μ case using an electrohydraulic brake unit EHB combined with an electric traction motor on the rear axle. [Figure 6a] FIG. 1 shows concept A of "Architecture I" of the driving dynamics system, i.e. EHB-Z for individual closed-loop control of each wheel on the front and rear axles combined with electric traction motors on the front and rear axles. [Figure 6b] FIG. 1 shows concept B of the "Architecture I" driving dynamics system, i.e. EHB-Z for individual control of each wheel on the front axle combined with the basic braking torque of the rear axle for ABS control at the rear axle using electric traction motors. [Figure 6c] FIG. 1 shows concept C of "Architecture I" of the driving dynamics system, i.e. EHB-Z for individual control of each wheel of the rear axle combined with the basic braking torque of the rear axle for ABS control at the rear axle using the electromechanical brake unit EMB. [Figure 6d] FIG. 1 shows Concept D of the "Architecture I" driving dynamics system, i.e. EHB-VA for individual control of each wheel on the front axle, for braking and ABS control at the rear axle using exclusively electric traction motors. [Figure 7a] This figure shows the motor characteristic map of a 250KW with high power motor and power boost via the new RSP-4Q inverter. [Figure 7b] FIG. 1 shows the structure of the new RSP-4Q inverter. [Figure 7c] FIG. [Figure 7d] FIG. [Figure 8] FIG. 13 shows a retraction-resistant inlet / outlet valve MV2k for pressure buildup and pressure reduction under high pressure gradients and braking pressures. [Figure 8a] FIG. 13 shows a retraction-resistant inlet / outlet valve MV2k for pressure buildup and pressure reduction under high pressure gradients and braking pressures. [Figure 8b] FIG. 13 shows a retraction-resistant inlet / outlet valve MV2k for pressure buildup and pressure reduction under high pressure gradients and braking pressures. [Figure 8c] FIG. 13 shows a retraction-resistant inlet / outlet valve MV2k for pressure buildup and pressure reduction under high pressure gradients and braking pressures. [Figure 9a] FIG. 13 shows a novel pressure closed loop control using inlet / outlet valve MV2k (PPC-Gen-V1). [Figure 9b] FIG. 13 shows a novel pressure closed loop control using inlet / outlet valve MV2k (PPC-Gen-V2). [Figure 10] FIG. 1 shows “Architecture II” of the driving dynamics system, i.e. the E-Axle module with the axle control electronics S-ECUVA and S-ECUHA. [Figure 11a] FIG. 1 shows the “architecture II” of the driving dynamics system, i.e. the E-axle module I with two electric motor brake units and one electric traction motor. [Figure 11b] FIG. 1 shows “Architecture II” of the driving dynamics system, i.e. E-Axle module II with one electro-hydraulic brake unit and two electric motor brake units. [Figure 11c] FIG. 1 shows “Architecture II” of the driving dynamics system, i.e. E-Axle module III with one electro-hydraulic brake unit and one electric traction motor. [Figure 11d]FIG. 1 shows “Architecture II” of the driving dynamics system, i.e. E-Axle module IV with one electro-hydraulic brake unit and two electric traction motors. [Figure 12] FIG. 1 is a diagram showing a comparison of the braking torque gradient and operating range of an electric traction motor TM, an electrohydraulic brake unit EHB, and an electric motor brake unit EMB. [Figure 12a] FIG. 1 illustrates a decision heuristic involving evaluation of feature maps, core data and signals. [Figure 13] FIG. 1 shows "Architecture III" of the driving dynamics system, i.e. the wheel module with wheel control electronics for the electric brake units and electric traction motors. [Figure 13a] FIG. 1 shows "Architecture III" of the driving dynamics system, i.e. a wheel module with four electric motor brake units and four electric traction motors.

[0120] FIG. 1d shows a typical simulation of an AMS test in which the brake system is designed according to the prior art. In the simulation, 10 follow-up braking maneuvers at 100 km / h are simulated. If the so-called AMS fade test is used as the basis for the dimensioning of the maximum pressure (Bremsenhandbuch, 5.Auflage, Kap.6.3.2, Abbildung 6.11), the wheel brakes of the front axle are typically heated to about 600° C. and the wheel brakes of the rear axle to about 500° C. In this case, the pedal force in a standard vacuum brake booster increases by about 80%, i.e. in the fade case, the brake system must be designed for a pressure 80% higher than that required for normal locking pressure. With the corresponding safety reservoir, a typical brake system is therefore designed for a maximum pressure of 200 bar to 220 bar.

[0121] In Fig. 1e, a currently available brake management with electrohydraulic brakes is shown in connection with an electric traction motor. The flow is detailed in Kap. 19.3.2 and Kap. 19.3.3 of the Bremsenhandbuch 5.Auflage and is also shown in Fig. 1a. This management is expanded as one of the core ideas of the present invention. However, it is characterized in that hydraulic braking is performed at the beginning of braking and at low vehicle speeds (area B), whereas generator braking is gradually increased at speed v1 and gradually decreased to speed v2. This means that hydraulic braking and no regeneration are performed at low vehicle speeds (v1<10 km / h, area B) and at high vehicle speeds (v2>60 km / h, areas E2, D), respectively. Furthermore, the capacity that can be provided by regenerative braking, e.g. the braking torque M between v1 and v2, is also shown in Fig. 1a. max Strong braking above v2 and regenerative braking above v2 are not utilized. That is, large braking torque is max,TM up to 1000 kW, but is not utilized in this speed range (range E1). This is often technically conditioned, for example, if the braking layer used is not designed for a relatively large recuperation. This is limited, for example, in the system described in DE 10 2012211278 A1, by the fact that the storage chamber of the ESP-hev unit can only absorb a limited volume, resulting in limited fade.

[0122] At higher decelerations and speeds, safety aspects are also important: for example in ABS cases, the braking torque of the electric traction motor could result in the wheels being locked, so regenerative braking is not performed. The driving dynamics system of the present invention now provides for the first time a correction by central control of the electric traction motor and the electrohydraulic brake unit. Note that in the prior art fade strategies, regenerative braking is not provided in the areas E1 and E2.

[0123] For the reasons mentioned above, in known systems the potential for regenerative braking as well as optimization of friction braking for the AMS fade case is not utilized, since the latter occurs precisely at speeds above about 100 km / h and during full braking. In this case, according to the prior art (see FIG. 1), purely hydraulic braking is performed. For example, if the braking power in the AMS test is taken over 30% by the electric traction motor (M el,TM,AMS ), the heating of the braking system is significantly reduced and therefore the fade effect should also be significantly reduced. The braking system can then be designed for a significantly lower maximum pressure, for example 140 bar to 160 bar. The maximization of the driving dynamics system according to the invention with closed-loop control has three effects with considerable cost and weight savings: 1. Regeneration can be maximized, which increases the range of electric vehicles, and regeneration can be used for the operation of heat pumps. 2. Friction brakes can be simplified, for example with easier cooling, less wear and smaller brake discs, and furthermore disc brakes can be replaced by lower cost drum brakes. 3. Downsizing of the electro-hydraulic brake becomes possible, in particular by using an EC motor for a smaller maximum torque, designing the wheel control valves with a lower maximum pressure, reducing the weight of the electro-hydraulic brake unit EHB as well as a smaller volume for the pressure supply unit of the electro-hydraulic brake unit.

[0124] In figure 2, an "architecture I" of an advantageous driving dynamics system for the joint operation of an electric traction motor (TM3) on the front axle and / or an electric traction motor (TM1, TM2) on the rear axle in combination with an electrohydraulic brake system of topology EHB-Z or EHB-VA according to figure 2 is shown. The central control unit here has the following functions: (A) A base brake with thermal and energy management of the energy supplied to and discharged from the traction motor (electrical energy, thermal energy); · (B) AEB emergency braking with electronic brake force distribution (EBV); (C) Regenerative braking on multiple axles; (D) ABS control with base braking torque assistance and / or common braking torque control; (E) Braking behavior in the event of a malfunction of the electrohydraulic brake units EHB-Z, EHB-VA; (F) Yaw moment intervention by individual braking torque intervention for each wheel; and / or (G) Wheel-specific braking torque intervention for wheel-specific regenerative braking, The control unit 100 assumes control of the braking torque of the electric traction motors TM1, TM2, TM3 and the electrohydraulic brake units EHB-Z, EHB-VA for at least one of the

[0125] The driving dynamics system transmits setpoint values, in particular the braking setpoint moment or the braking setpoint pressure, to the different units. For certain functions (e.g. functions (C), (E), (F) mentioned above), setpoint signals for the open-loop or closed-loop pressure control, control signals for solenoid valves for functions such as the switching duration of the opening time or the PWM frequency in throttling action, and / or preload of pressure supply devices for pressure build-up or pressure reduction are also set.

[0126] Furthermore, M-ECU DOMAENE is the interface to the control unit or the domain M-ECU for autonomous driving AD , and can evaluate further information that is useful for an effective and predictive closed-loop control, for example camera information about the nature of the road (snow, ice, rain) or information about the environment (distance from occupants and / or other vehicles).

[0127] An exemplary structure of a vehicle architecture with the architecture of a driving dynamics system with hydraulic lines and signal lines between the units and sensors is shown in Fig. 2a. DOMAENE A central control unit, preferably including three microcontrollers μC1, μC2, μC3 for implementing a “2-out-of-3” architecture, controls the control unit of the electrohydraulic brake unit (M-ECU). BM ) as well as the electric traction motor TM1 (optionally TM2) on the rear axle and the electric traction motor TM3 on the front axle, in particular via redundant data lines.

[0128] Central control unit M-ECU DOMAENE may in particular have at least one very powerful microcontroller and a large memory (dimensioned in the gigabyte range), which allows automatic adaptation via artificial intelligence (AI) to be carried out before the first start of driving the vehicle and / or during vehicle operation. Alternatively, a central computer can be used instead of a domain computer, or it is possible to use the typically relatively large resources of a central computer designed in particular for processing multimedia data utilized for applications via AI.

[0129] Central control unit M-ECU DOMAENE So, the wheel v R1 ~v R4Data from the wheel speed sensors and preferably further sensor signals S1, S2, Si etc. are received. The sensor signals S1, S2, Si can be provided by yaw moment sensors, acceleration sensors and / or weight sensors, which are important for the central control via the vehicle model, since these sensors enable the central control or at least facilitate the optimization of the central control. Thus, the weight sensors can advantageously be used to adapt the recuperation strategy in dependence on the weight. The yaw moment sensors are useful for driving dynamics interventions, such as torque vectoring or ESP yaw moment interventions, and the acceleration sensors assist in the calibration of the relationship between the brake pressure of the hydraulic brake unit (EHB), the achieved brake torque or pressure and the achieved vehicle deceleration. Further sensors or data from the autonomous driving system, such as data from cameras and LiDAR sensors, map material or data on interactions with the environment and other vehicles, such as Car2X (V2x) or Car2Car (V2V) communication, can likewise be used to carry out traffic-specific braking torque interventions or to slow down the vehicle in a targeted manner, and also in error cases, for example in the event of a partial failure with a reduced maximum deceleration, to drive the vehicle at an adapted speed or with earlier deceleration.

[0130] In addition, an electric power steering unit EPS of the front axle and an electric parking brake (EPB1, EPB2) of the rear axle as an option are preferably further provided for communication with the central domain. The introduction of the EPS allows coordinated driving dynamics interventions, e.g. torque vectoring, ESP yaw moment interventions via the electrohydraulic brake unit EHB in addition to the EBS failure or partial failure, for steering or to assist the vehicle's electric power steering unit. Furthermore, the integration of an electric parking brake EPB is advantageous, since besides the purely stationary safety device, the parking brake can also perform dynamic braking or emergency functions, for example as described in WO2020165255.

[0131] 2b shows an exemplary structure of another vehicle architecture of the driving dynamics system according to the invention with the EHB-Z with hydraulic lines and with signal lines between the brake unit and the sensors. DOMAENE Preferably, the two redundant control units ECU1 and ECU2 are connected to each other, in particular via redundant data lines. EHB and ECU2 EHB A control device for a hydraulic brake unit (M-ECU) BM ) contains three microcontrollers μC1, μC2, μC3, which communicate with the electric traction motors TM1, TM2 of the rear axle and the electric traction motor TM3 of the front axle, realizing a 2-out-of-3 architecture. In contrast to Fig. 2b, the EHB-Z does not incorporate pedals and has only one hydraulic line to the wheel brakes of the rear axle and one electric traction motor each for one wheel of the rear axle, so that the braking torque control for the various functions ABS, ASR, ESP, EDB and regenerative braking is performed by the electric traction motors, while the electrohydraulic brake unit EHB-Z only provides the basic braking torque. Further details regarding the hydraulic layout of the EHB-Z are shown in Fig. 6b.

[0132] Central control unit M-ECU DOMAENE Now, let's take the data v from the wheel speed sensor. R1 ~v R4and preferably further sensor signals S1, S2, Si, etc. are received. The sensor signals S1, S2, Si can be provided by a yaw moment sensor, an acceleration sensor and / or a weight sensor, which are important for the central control via the vehicle model, since these sensors enable the central control or at least facilitate the optimization of the central control. Thus, the weight sensor can advantageously be used to adapt the recuperation strategy in dependence on the weight. The yaw moment sensor is useful for driving dynamics interventions, such as torque vectoring or ESP yaw moment interventions, and the acceleration sensor assists in the calibration of the relationship between the brake pressure of the hydraulic brake unit (EHB) and the achieved brake torque or brake pressure and the achieved vehicle deceleration. Further sensors or data from the autonomous driving system, such as data from cameras and LiDAR sensors, map material or data of interaction with the environment and other vehicles, such as Car2X (V2x) or Car2Car (V2V) communication, can likewise be used to perform traffic-specific braking torque interventions or to decelerate the vehicle in a targeted manner or to drive the vehicle at an adapted speed or with earlier deceleration in error cases, for example in the case of a part failure in which the maximum deceleration is reduced.

[0133] In addition, an electric power steering unit EPS of the front axle and an electric parking brake (EPB1, EPB2) of the rear axle as an option are preferably further provided for communication with the central domain. The introduction of the EPS allows coordinated driving dynamics interventions, e.g. torque vectoring, ESP yaw moment interventions via the electrohydraulic brake unit EHB in addition to the EBS failure or partial failure, for steering or to assist the vehicle's electric power steering unit. Furthermore, the integration of an electric parking brake EPB is advantageous, since besides the purely stationary safety device, the parking brake can also perform dynamic braking or emergency functions, for example as described in WO2020165255.

[0134] Figure 3 shows a fade strategy of the driving dynamics system with full utilization of the braking force of the electric traction motor over the entire speed characteristic of the vehicle and up to the maximum braking torque of the electric traction motor used. Full utilization here is possible because in the driving dynamics system, as shown in Figure 2a, the central domain has all the important information and therefore in critical driving situations, for example during ABS control operations, the adaptation of the braking action via the electric motor can be performed very quickly with minimal time delay. New electric motors in high-voltage technology (>700V) can increase or decrease the electric braking torque via the electric motor very dynamically from 10000Nm / s to 30000Nm / s. Thus, in the ABS case, before the electrohydraulic brake unit EHB takes over the ABS control, the braking torque can be generated by the electric traction motor at the axle, in an electric drive (see table) or at the wheels with individual drives per wheel or in an electric axle with a torque vectoring module, almost as fast as in the case of hydraulic brakes (typically 1000 bar / s to 2000 bar / s = 20000 Nm / s to 4000 Nm / s). The control strategy during ABS operation with both electric traction motor and electrohydraulic brake unit EHB is further shown in FIG. 5a. Thus, although the first closed-loop control cycle is not completely optimal, safety-critical situations that could cause the vehicle to become unstable cannot occur. Furthermore, in critical driving situations where automatic emergency braking (AEB) is used, the shortcomings of the first control cycle can be sufficiently compensated for by shortening the TTL.

[0135] In the figure, the torque-speed characteristic map of the electric drive motor of a plug-in hybrid or electric vehicle (e.g. BMW i3) with a vehicle weight of 1365 kg is used as an example. The electric traction motor in this case has a maximum power of about 130 kW and a maximum torque of 250 Nm and operates with a transmission ratio of 9.5, i.e. torques of up to 2400 Nm are available at the vehicle axles for drive and deceleration. For a maximum permissible vehicle weight of 1710 kg, if a weight distribution during braking with a maximum deceleration effect of 40% on the rear axle and 60% on the front axle is taken as the basis, an axle braking torque of 3400 Nm at the front axle and an axle braking torque of 2465 Nm at the rear axle are required. This allows the rear axle to be braked completely electrically up to a speed of about 70 km / h.

[0136] At the design point for the AMS fade test, at a speed of 100 km / h, it is possible to achieve approximately 50% of the braking power on the front axle and up to approximately 70% of the braking power on the rear axle, which means that the brakes on the front axle only receive half the friction power and the rear axle only 30% of the friction power.

[0137] The high additional braking torque, which is supplied over a large speed range, can be used to significantly reduce heating of the friction brakes and can be used in the AMS test conditions at 100 km / h as well as at higher speeds where a lot of kinetic energy is absorbed by the friction brakes. The latter is advantageous for sports vehicles where ceramic brakes are typically used, which are very expensive. The rear axle can also be completely thermally de-loaded at speeds up to 70 km / h, which allows for a very significant de-loading even in the particularly critical AMS test. This allows for the use of less expensive drum brakes.

[0138] The central control unit of the driving dynamics system, which preferably also detects the vehicle weight, can then increase the braking force through regenerative braking even at low loads, so that the regenerative strategy is adapted depending on the vehicle load.

[0139] The problem is the battery's ability to absorb high pulse powers, especially at high charge states. In this special case, it is conceivable that the power is not fed back to the battery, but is at least partially dissipated in the electric traction motor by an intelligent field-oriented vector control (Id, Iq) in the electric traction motor, so that no energy is fed back. Alternatively, an additional resistor can be used that can dissipate heat. In this case, the heat generated via the resistor can advantageously also be used for heating the vehicle or via a heat exchanger for cooling the vehicle. The energy management means have already been described above in additional detail.

[0140] Additionally, when a special inverter (RSP-4Q inverter) is used, which can alternatively connect the motor windings in series or in parallel, an additional torque boost is possible at high motor speeds or high vehicle speeds. This also increases the braking torque at high vehicle speeds due to generator braking, so that even more kinetic energy can be recuperated. Alternatively, as shown in FIG. 4, the TTL time (Time-to-Lock) can also be reduced further at high speeds, which can likewise be used to advantage to reduce the braking distance, since electric braking can be performed in addition to the hydraulic braking.

[0141] Figure 4 shows how the inventive function of the AEB emergency braking (function B) can be realized with the inventive control of the driving dynamics system by significantly adapting the EBV control in the sense that, in addition to the brake activation, the braking distance is further shortened via the electric traction motor in the event of electric emergency braking. In Figure 4, an electric traction motor with the output data of Figure 3 (130 kW, 250 Nm, transmission ratio 9.5) and a torque gradient of 15000 Nm / s are set by way of example. In the electrohydraulic system EHB, a division of the monochromatic brake circuit is used, i.e. a brake circuit for the front axle and a second brake circuit for the rear axle of the vehicle. Curve BM TM1-VA and B.M. TM2-HA shows the braking torque increase of the electric traction motor on the front axle VA or rear axle HA, respectively, with in particular a braking torque gradient of 15000 Nm / s. This increase is taken into account for the electric brake force distribution EBV in such a way that it is ensured that the front and rear axles simultaneously achieve their respective maximum braking torques for a deceleration of, for example, 1 g, and at the same time that the pressure characteristics are distributed to the front and rear axles via the advantageous hydraulic brake system shown in Figures 6a to 6d ff., such that the design priorities (see Table 1 of priorities) are taken into account.

[0142] As shown in a simplified manner, the braking torque increases further after reaching the maximum braking torque (marked in the figure at about 1 g), but a further time-dependent braking torque characteristic and a TTL for relatively high decelerations (e.g. up to 1.4 g for a sports vehicle) are shown. When an ABS case occurs, the braking torque, which typically occurs at decelerations of about 1 g, is consequently reduced and an ABS control action follows, as will be further explained below with reference to Figures 5, 5a, 5b, 5c et seq.

[0143] Here, the curve BM EHB-HA shows the braking torque characteristic for the electrohydraulic brake of the rear axle, while curve BM HA,EHB+TM2-HAindicates the sum of the braking torque characteristic of the electrohydraulic brake of the rear axle and the braking torque characteristic of the traction motor TM2 assigned to the rear axle.

[0144] Furthermore, the curve BM EHB-VA shows the braking torque characteristic of the electrohydraulic brake on the front axle, and curve BM VA,EHB+TM2-VA indicates the sum of the braking torque characteristic of the electrohydraulic brake of the front axle and the braking torque characteristic of the traction motor.

[0145] The braking torque corresponding to the locking pressure of the front axle VA is shown as an upper horizontal curve BLM-VA, while the braking torque corresponding to the locking pressure of the rear axle HA is shown as a lower horizontal curve BLM-HA.

[0146] The point where the curve of the braking torque achieved by the brake units EHB-VA, TM1, EHB-HA, TM2 intersects with the horizontal curves BLM-VA, BLM-HA, the respective locking pressure is obtained, the time to reach this point is called the time-to-lock (TTL).

[0147] The TTL for the electrohydraulic brakes EHB-VA, EHB-HA alone is approximately 140 ms, but is approximately 90 ms if the regenerative braking torque of the traction motors TM1, TM2 is additionally used. Using closed-loop control of the driving dynamics system, the TTL in the simulation can thus be reduced by the difference ΔT from 140 ms to 95 ms, which has a noticeable effect on the braking distance. At a speed of 100 km / h, for example, 45 ms here corresponds to a travel distance of approximately 1 m. This is already a noticeable improvement compared to the typical braking distance of 25 m with ABS braking.

[0148] Such an improvement of one meter in stopping distance is a huge target for applicators of ABS braking systems.

[0149] FIG. 5 shows another basic idea of ​​synergistic use of the braking torque of the electric traction motor and the braking torque of the electrohydraulic brake unit based on typical ABS control characteristics when there is high pressure on the asphalt, i.e. the so-called "high μ case".

[0150] As already mentioned above, the use of electric traction motors in ABS control is not problematic since the traction motors can ramp up and down the braking torque very quickly after said ramp up and down.

[0151] In FIG. 5, a curve of the vehicle deceleration is shown, as well as curves of the wheel speeds of the four wheels of the vehicle.

[0152] Advantageously, the electric traction motor generates a basic braking torque VA during ABS operation, which is shown for an exemplary arrangement of the electric traction motor on the front axle in Fig. 5. This results in the preload of the electrohydraulic brake unit EHB being able to be reduced by the basic braking torque of the electric traction motor, as a result of which the locking pressure can be generated more quickly, as shown in Fig. 4, and the pressure required on the EHB for ABS control is reduced.

[0153] This can be used for downsizing of braking systems, which generally have to create a preload 20%-40% higher than the maximum wheel pressure. However, if 50% of the basic braking torque is created via the electric traction motor, only a pressure of 70-80 bar is needed for ABS operation, instead of the typical design of 120-140 bar. However, after the heating of the brake system has been significantly reduced by generator braking (see the embodiment described above in connection with FIG. 3), the design of the EHB to 100 bar is sufficient for a safe control operation.

[0154] FIG. 5 shows how the basic braking torque at the front axle VA is generated by the electric traction motor. In this case, the difference ΔP to the desired preload at the front axle VA is relatively small. The pressure control for the two wheels of the front axle VA has a correspondingly small amplitude of the ramp, so that the electrohydraulic brake unit can be made more compact.

[0155] This has a significant impact on the braking system, since on the one hand the pressure supply requires a smaller volume to generate the required fluid volume and the electric motor of the electrohydraulic brake unit EHB only has to generate 50% of the braking torque. Furthermore, the valve design of the hydraulic control unit HCU of the EHB can be adapted by using smaller or less expensive valves that can be designed for a significantly lower pressure resistance. This basic idea allows the cost of the EHB to be reduced by around 10%. Furthermore, friction brakes can be implemented significantly more cost-effectively, since the thermal load is reduced and a smaller braking torque has to be transmitted to the brake shoes. In sports vehicles, expensive ceramic brakes can be replaced by significantly less expensive grey cap brakes.

[0156] In Fig. 5a and Fig. 5b, the deceleration of the ABS control using an electric traction motor is shown for a standard ABS system. R1 The time characteristics of the wheel speed are shown in comparison.

[0157] In FIG. 5a, a typical flow at the beginning of a closed loop control cycle of pressure reduction in ABS operation with a standard ESP device or a one-box system is shown for low friction values, for example on snow.

[0158] In the upper graph the wheel speed is plotted as a function of time t. In the lower graph the pressure is plotted as a function of time t (upper curve). Furthermore the valve opening status over time t is shown diagrammatically (lower curve).

[0159] After a time t0 due to the dead time of the system, a locked wheel is identified because the wheel speed v at that point is greater than the reference speed v ref The pressure is then reduced by the outlet valve. The outlet valve is then opened to reduce the pressure. The valve is opened for a time t VM During this time phase, the wheel speed is Δv i After the valve opening phase, the pressure reduction continues for a period t ab , which is simplified and shown linearly. During this time phase, the wheel speed is further reduced by Δv2 until the wheel stabilizes. Then the valve is closed again. After that, the wheel speed is again reduced to the reference speed v ref This is followed by a stepwise pressure increase (not shown) to bring the pressure to a level of 0.1 mmHg, preferably via a small stepwise pressure increase via an inlet valve.

[0160] FIG. 5b shows ABS control of the wheels via the traction motors.

[0161] In the upper graph the wheel speed is plotted as a function of time t, in the lower graph the pressure is plotted as a function of time t.

[0162] In the ABS control using the traction motor described herein, preferably a central control unit M-ECU DOMAENEIf wheel speed sensors with high resolution and short latency of data transmission to the central computer are used, ABS cases, which are characterized by wheel speed deviations from a reference value, can be detected more quickly, especially based on accurate modeling of the vehicle model in the central computer. This results in a shorter delay time t0 and thus a smaller speed difference Δv in the inventive control of the driving dynamics system. Furthermore, since no valves are required in the ABS control with electric traction motors and the time delay of the torque change in the inverter of the high-performance traction motor is negligibly small, the reduction of the braking torque can be achieved with a further time delay t MV without delay, immediately after the initial delay t0, especially in the case of low roadway friction values ​​and large braking torque gradients (see the illustration of the braking torque gradient in FIG. 12). Furthermore, due to the high resolution, an improved wheel acceleration control with a central domain control can be realized, whereby the wheel target moment can be achieved more quickly and without overshoot. The increase in the braking torque then continues, likewise without delay in valve actuation and with the precision of the motor control with the torque and motor speed control cascade (i.e. taking into account in particular the torque / current of the electric motor of the pressure regulator, the position of the piston in the piston-cylinder system of the pressure regulator and the actuator speed, i.e. the positioning speed of the piston of the regulator), until the reference speed v ref is achieved again much more quickly and without oscillations in the braking torque characteristic. Due to the small deviations in the reference speed, the braking distances in the control with electric traction motors in the ABS can be reduced compared to standard ABS systems, while at the same time noise is reduced due to the control with fewer pressure oscillations. In other words, the same control quality can be achieved with a smaller braking torque gradient in the case of closed-loop control with traction motors compared to the braking torque gradient of the electrohydraulic brake unit EHB, because the critical time delay t caused by the solenoid valve is eliminated. VMis eliminated. Also, with a powerful computer and high-resolution wheel speed sensors, the response time t0 can be reduced, i.e. wheel lock can be identified earlier and adjusted more quickly.

[0163] FIG. 5c shows a further inventive advantage of a common braking torque modulation in a closed-loop control operation, for example for a negative μ jump, when the vehicle goes, for example, from asphalt onto snow.

[0164] In Figure 5c, the pressures or the corresponding braking torques at the front and rear axles VA and HA are plotted as a function of time t, where the braking torques generated by the traction motors at the front and rear axles as well as the overall curves of the braking torques at the front and rear axles are shown.

[0165] In FIG. 5c it can be seen, albeit in a simplified manner, that the two wheels of the front axle have the same braking torque or the same braking pressure, and that both the front and rear axles are equipped with traction motors on the axles, each of which provides a base braking torque for the total braking torque of the respective axle. brems,ges,Vrad or M brems,ges,Hrad Whereas, the braking torque of the traction motor M brems,TM,Vrad or M brems,TM,Hrad and the hydraulic braking torque (not shown) of the electrohydraulic brake unit EHB of the front or rear wheels act additively. If the braking torque is reduced, first the braking torque M brems,TM,Vradcan be reduced, followed by a pressure reduction by the EHB with the above-mentioned time delay t0. This advantageously allows the braking torque to be adapted very quickly, with the gradient increasing as soon as the EHB has been able to reduce the pressure. This has a positive effect on the slowdown of the front wheels, not shown. With a short time delay, a braking torque reduction at the rear axle or a braking torque M quickly applied by the electric traction motor (as described above for the front axle) can be applied. brems,TM,Hrad The braking torque M obtained without any further time delay t0 from brems,TM,Hrad is then followed by a reduction in the wheel speed, so that here too the wheel speed does not decrease so sharply.

[0166] FIG. 5d shows the approach according to the invention for another control situation in which the vehicle is driven on a road surface that is as uniform as possible, for example a snow-covered road surface (the so-called low μ case).

[0167] The braking torque M formed at the right front wheel VR, the left front wheel VL, the right rear wheel HR, and the left rear wheel HL at the wheels brems is plotted as a function of time t.

[0168] Here, advantageously, the front axle is closed-loop controlled by the EHB, whereas the relatively low braking torque for the rear axle is obtained by the two traction motors TM1 and TM2, in which case the concept of FIG. 6b or FIG. 6d described below is the basis.

[0169] Alternatively, the control can also be transferred to a drive concept in which the rear axle is provided with an electromechanical brake unit EMB according to the concept of FIG. 6c and the front axle is provided with an electrohydraulic brake unit EHB. The electric motor brake unit EMB thus has the same advantages as a traction motor, for example a high braking torque gradient and a precise braking torque control due to the torque control and acceleration control of the motor of the EMB. Furthermore, the electric motor brake EMB is superior to an electric traction motor in terms of the braking torque gradient (see the diagram in FIG. 12). However, at low friction values ​​the clamping effect of the brake shoes of the EMB is lost.

[0170] FIG. 6a shows a hydraulic braking arrangement for four wheel brakes with electric traction motors TM1 on the rear axle and TM2 on the front axle of the vehicle, which is advantageous for integration into a driving dynamics system according to a first embodiment ("architecture I"). The braking arrangement may furthermore have a redundant pressure supply in the form of a piston-cylinder unit, which is driven via the electric motor and the spindle drive. The pressure supply may be provided with a current sensor i / U and an angle sensor a / U as well as a temperature sensor T / U for measuring the motor temperature of the EC motor. The piston-cylinder unit may furthermore have redundant phase terminals, redundant electronics and / or redundant on-board electrical supply terminals BN1 and BN2 as well as the chassis domain of the central control unit (M-ECU). Chassis-Domain ) The brake system may furthermore have a sensor ECU and an E-pedal with a sensor, in particular with a force displacement sensor based on a distance difference measurement principle (see US 13 / 883192), which can be transformed into an E-pedal concept for detecting pedal forces. The sensor ECU can communicate directly with a central control unit of the chassis domain.

[0171] In addition, for each wheel brake, a special bidirectional inlet / outlet valve (simply called MV 2k) can be used, in which case simultaneous forward and backward movements of the pistons of the piston-cylinder unit allow a pressure build-up or a pressure reduction. Alternatively, the valves can be provided with different terminals, so that the cross-sectional area of ​​the valve can be controlled by appropriate energization during pressure build-up or pressure reduction. If, for example, the valve seats are connected to wheel brakes, different pressure gradients can be realized during pressure reduction, so that noise is suppressed and at the same time the pressure in several wheel brakes can be reduced. In this case, the pressure build-up is carried out simultaneously via a volume open-loop control by a pressure supply unit or in a multiplexed manner.

[0172] When the valve seat is connected to the pressure supply, pressure is built up via a classical preload control. Outlet valves AV1-AV4 are advantageous for the latter method, but do not necessarily have to be provided for pressure reduction. It is worth using the outlet valves only in extreme situations, since in this way the volume of the pressure supply disappears into the reservoir, and in the case of relatively long control interventions it is necessary to return the volume from the reservoir by pulling back the piston (see the regulation strategy described in EP 2 580 095). The reduction of the volume via the outlet valves should therefore be set so that the braking process is completely terminated in order to avoid critical control interruptions, and only after the end of the braking process does additional pumping have to be performed. Alternatively, for the pressure supply, a double-acting piston with continuous pumping can be provided, as described in EP 3 145 771, or an electric traction motor can take over the braking torque closed-loop control in the time phase of the interruption.

[0173] Such a system configuration requires the inlet / outlet valve MV 2kOr the freedom of selective pressure reduction via the outlet valves. The use of outlet valves is therefore optional and one to four outlet valves can be provided selectively. The outlet valves here only provide an additional freedom in the possibility of pressure reduction. Advantageously, outlet valves can also be provided on all wheels when the system is introduced and the number of outlet valves can be reduced step by step later within the framework of product maintenance.

[0174] Alternatively, it is also possible to combine the known multiplex method in two wheel brakes with conventional pressure regulation in two further wheel brakes via inlet / outlet valves, where, as an option, standard inlet valves are used instead of the inlet / outlet valves or MV 2k The valves are used only for pressure build-up and pressure reduction in brake booster operation.More advantageously, an electric traction motor can be used to realize an effective fade strategy in the sense of downsizing (see FIG. 5), where the electric traction motor is used to provide the base braking torque in ABS operation and / or to achieve a faster TTL in the emergency braking function AEB (see FIG. 4).

[0175] Furthermore, it is advantageous to set an intentional braking torque intervention as a setpoint or setpoint characteristic via the domain, which also advantageously sets a time characteristic for the braking torque increase or reduction, so that an efficient synchronization with the braking torque characteristic of the electric traction motor can be achieved. The intervention can be performed individually for each axle or individually for each wheel. In this case, the intervention for the individual wheels is mainly used for yaw moment control, for example for torque vectoring interventions, and is preferably performed in time synchronization with the steering interventions of the electric power steering EPS.

[0176] Music Video 2k The use of the valves also allows for the diagnosis of wheel circuit faults and, in the event of a fault, the MV 2kThis has the advantage that the wheel circuit can be isolated by closing the valve. In this way, a three-channel control operation is possible that can continue to be used for ABS control even when the wheel circuit fails, and a three-channel control operation is also possible that can be used for steering assistance or yaw moment intervention for emergency steering when the electric power steering unit fails or partially fails.

[0177] Furthermore, the brake units are preferably constructed redundantly, for example with redundant coils and electronics, so that the individual brake units can continue to be operated in the event of a partial failure. In this way, a two- or three-fold redundancy of the braking function can be achieved with high reliability. Critical situations may still prevail even if the braking power is reduced. In the event of a partial failure of the pressure supply, the reduced dynamics of the 1×3 phase instead of the 2×3 phase still provide 50% of the maximum braking torque, i.e. about 70 bar in a 140 bar design. This allows a full ABS operation up to the locking pressure to be achieved on both of the two axles, since in this case the electric traction motor can provide the assist torque on one or both axles.

[0178] The hydraulic braking system with the vehicle dynamics system of this specification has a very simple and cost-effective structure (few solenoid valves, downsized pressure supply section) and yet meets all SAE Level 4 redundancy requirements as defined above.

[0179] In Fig. 6b a second embodiment of the electrohydraulic brake unit EHB is shown with two electric traction motors TM1 and TM2 on the rear axle and a traction motor TM3 on the front axle. The traction motor TM3 can be omitted, but here the two traction motors TM1 and TM2 are involved in the system, mapping topology B of Fig. 2.

[0180] Only hydraulic lines lead from the pressure supply of the electrohydraulic brake unit EHB to the two wheel brakes RB3 and RB4 of the rear axle, on which advantageously only low-cost drum brakes are used.

[0181] The electric traction motors TM1 and TM2 are powerful motors with an output of more than 50 kW per wheel. The braking torque build-up and braking torque reduction are carried out dynamically. The traction motors TM1 and TM2 are now responsible for the braking torque control, whereas the EHB is only used in normal operation to provide the basic braking torque for the rear axle.

[0182] The closed-loop control operation is similar to the case shown in Figure 5, with the difference that the rollers of the EHB and the traction motor are exchanged and the EHB forms the base braking torque instead of the electric traction motor. On the front axle, the ABS control is performed by the EHB and the optional traction motor TM3 forms the base braking torque. If the optional traction motor TM3 is used on the front axle, cheaper drum brakes can still be used.

[0183] In the first error case, for example in the event of a failure in the hydraulic connection to the wheel brakes of the rear axle, the connecting line is isolated via a shut-off valve and the traction motor takes over the control function entirely at that point. This means that, depending on the power and speed of the traction motor, the rear axle deceleration may be limited, but all safety-critical functions (μ-jump, ABS for low μ) can still be controlled very reliably, and steerability (priority 3) is ensured by front axle pressure control and / or by actuating the steering EPB via the driving dynamics system.

[0184] Significantly, the vehicle speed is limited in such an error case (e.g. to 75 km / h in the motor design shown in FIG. 3), which would result in long braking distances in the absence of speed limiting, but is otherwise not very critical from a safety technical point of view.

[0185] In the second error case, if the electric traction motors TM1 and TM2 of the rear axle fail, the ABS is controlled for each axle via the pressure supply. Steering intervention is then preferably carried out via the EPS activation control by the driving dynamics system. If only one traction motor fails, the steering intervention can likewise be carried out via the traction motor that is still operational.

[0186] Pressure control can be maintained at a lower power output in the event of a partial failure of the pressure supply, for example in the event of a winding failure in the electric motor, with the second strand of the 2x3 phase taking over control at 50% power output. In this case, the traction motor on the rear axle can also take over anti-slip control (ASR) as well as torque vectoring or yawing moment intervention.

[0187] The embodiment of the hydraulic brake system of Fig. 6b is even simpler than the system shown in Fig. 6a, since fewer solenoid valves and hydraulic lines are provided and drum brakes can be used, whereby the embodiment according to Fig. 6b likewise meets the SAE Level 4 redundancy requirements, as indicated above.

[0188] In FIG. 6c a third embodiment is shown with two electromechanical brakes EMB1 and EMB2 on the rear axle and a traction motor TM3 on the front axle.

[0189] The traction motor TM3 can be omitted, but here electric motor brake units EMB1 and EMB2 are involved in the system, mapping out Topology B and Topology D in Figure 2. Only hydraulic lines lead from the pressure supply of the EHB to the two wheel brakes RB3 and RB4 of the rear axle. In particular, only inexpensive drum brakes can be used on the rear axle.

[0190] The electromechanical brake units EMB1 and EMB2 are dynamically implemented in the braking torque build-up and braking torque reduction and are responsible here for the braking torque control. The electrohydraulic brake EBS is used in normal operation only to form the basic braking torque for the rear axle. The closed-loop control operation is carried out in the same way as described above with reference to FIG. 5, with the difference that the rollers of the EHB and EMB are exchanged and the EHB forms the basic braking torque. On the front axle, by contrast, the ABS control is carried out by the EHB and the traction motor TM3 as an option provides the basic braking torque. If the traction motor TM3 is used as an option on the front axle, then here too less expensive drum brakes can be used.

[0191] In the first error case, for example if the hydraulic connections to the wheel brakes on the rear axle fail, the connecting lines are isolated via shut-off valves and EMB1 and EMB2 take over the complete control functions at the individual wheels of the rear axle. This allows all safety-critical functions (μ-jump, ABS for low μ) to be controlled very reliably even without hydraulic support from the EHB, while steerability (priority 3) is ensured by front axle pressure control and / or actuation control of the steering part EPB via the vehicle dynamics system.

[0192] The electromechanical brake units EMB1 and EMB2 are advantageously designed for a locking braking torque with a small fade reserve (20% reserve), but for cost reasons can also advantageously be designed for a braking torque below the locking limit (approximately 50% of the locking braking torque). In normal operation, the EBS assistance ensures that the controlled braking torque at maximum deceleration can be achieved without excessively strong thermal loads on the drum brakes. In the event of a hydraulic line failure, it is quite acceptable for the rear axle to apply a smaller braking torque to the overall deceleration than the front axle, since the influence on the extension of the braking distance is rather small. What is important is mainly the control behavior at low μ and μ jumps. In this case, 50% of the locking torque is sufficient for safe driving behavior.

[0193] In the second error case, if the electromechanical brake units EMB1 and EMB2 of the rear axle fail, the ABS is controlled for each axle via the pressure supply. A steering intervention is then preferably performed via the EPS actuation control by the driving dynamics system. If only one of the electromechanical brake units EMB (EMB1 or EMB2) fails, a steering intervention can also be performed via the electromechanical brake unit EMB (EMB2 or EMB1) that is still operational.

[0194] In the event of a partial failure of the pressure supply, for example in the event of a winding failure in the electric motor, pressure control can be maintained with less power, with the second strand of the 2x3 phase taking over with 50% of the torque. In this case, the electromechanical brake units EMB1 and EMB2 on the rear axle can also take on anti-slip control (ASR) as well as torque vectoring or yawing moment intervention.

[0195] The embodiment of the hydraulic braking system of Fig. 6c is even simpler than the system shown in Fig. 6a because fewer solenoid valves and hydraulic lines are provided and drum brakes can be used, whereby the embodiment according to Fig. 6c also meets the SAE Level 4 redundancy requirements as shown above.

[0196] Such a solution is preferably used when an electric traction motor is not provided on the rear axle or when both an electric traction motor on the rear axle and an electric traction motor on the front axle are not provided for intervention of the braking torque generation by the driving dynamics system, for example for hydrogen vehicles or hybrid vehicles which are not dynamic because the electric motor is tightly connected to the internal combustion engine.

[0197] FIG. 6d shows a fourth variant of an electrohydraulic brake unit EHB integrated into a driving dynamics system, in which only one electrohydraulic brake is provided for the front axle, while the rear axle is similarly provided with electric traction motors TM1 and TM2 for each wheel, as already described for FIG. 6b.

[0198] In contrast to the system of FIG. 6b, the rear axle is not assisted here by the basic braking torque from the EHB, i.e. the traction motors are preferably designed with a correspondingly high power, a braking torque is applied up to the locking limit, and dynamic control can also be performed. Such an arrangement is advantageous in sports or premium vehicles with powerful motor drives, where the motors are powerful enough and the rear axle electrohydraulic brake unit EHB is no longer necessary. In such an arrangement, friction braking on the rear axle is completely omitted. The traction motors TM1 and TM2 perform many functions (ESP intervention, ASR intervention, ABS intervention, EBV braking torque regulation) and are driven synchronously in time to the front axle electrohydraulic brake unit EHB via the driving dynamics system, i.e. the braking torque setpoint is also synchronized in time characteristics.

[0199] In FIG. 7a, two curves of the motor torque-speed characteristic map are shown, scaled by the gear ratio up to a maximum speed of 200 km / h for a 1800 kg vehicle, thus representing the motor torque-vehicle speed characteristic map. 1g=9.81 m / s 2 The braking torque for a deceleration of is calculated as the braking torque for the front axle (upper horizontal curve, dashed line) and the rear axle (lower horizontal curve, dashed line) with a weight distribution VA / HA of 65% / 35%. In the first motor torque vehicle speed-characteristic map 1 (marked "Mbrems_normal" in FIG. 7a), a typical design of a motor with a typical inverter is used as the basis. This is because the electric traction motor is designed for a constant power output, so that the power hyperbola is limited primarily by the voltage from a certain point P1. Furthermore, here, up to a speed v2, a maximum braking torque at the rear axle can be generated by the electric traction motor in generator operation.

[0200] In order to be able to optimally use the braking torque of the traction motor for braking even at maximum speed, it is advantageous to use an inverter which allows switching of the coils of the coil winding from a series circuit to a parallel circuit. This reduces the inductance by half and allows a higher torque to be generated at the same rotation speed at a given voltage, and also results in 100% higher torque dynamics, which is extremely advantageous for a highly dynamic braking torque control in ABS operation. Furthermore, the inverter is implemented in such a way that, like the 2x3-phase inverter concept, it is also possible to operate in the event of failure of one or more components (power semiconductors, coil windings), thus preventing a complete failure of the electric traction motor as a brake unit.

[0201] In another embodiment, other topologies known from the prior art and similar in effect can be used to solve the above-required functions, which generally have 24 to more than 42 switching elements to realize redundancy (2x3 phases) and switching between series and parallel circuits during operation, and which can also be used for the boost function.

[0202] In Fig. 7b an inverter is shown which, unlike similar systems in the prior art, has only 18 switching elements instead of 30 to 40 or more and which can be operated in four-quadrant operation like a standard inverter for a brushless motor. In this case the four quadrants result from positive or negative torque as well as positive or negative speed. Four-quadrant operation allows on the one hand a motor torque boost operating mode in which the torque is temporarily increased by up to 100%; On the other hand Achieve redundancy in the event of failure of one or more components (power switches, coil windings).

[0203] An inverter with the above-mentioned measures is, for the time being, more expensive than a standard converter with three phases, typically with six switching elements, due to the wiring and component costs. According to FIG. 6c, the application for the driving dynamics system described here is particularly attractive if the regenerative braking of the rear axle is performed exclusively during the activation of the service brakes and during ABS control operation, and thus there is a significant potential cost and weight reduction due to the omission of the friction brakes. Furthermore, inverter redundancy is not necessarily required for SAE Level 2, but meets the requirements for SAE Level 3, since control operation at the rear axle is still possible in the event of a partial failure of the electric traction motor. SAE Level 3 also corresponds to a prior art inverter concept with alternatively 30 to 40 components, since an equivalent brake system, for example a two-box brake system, would be even more costly than a typical one-box brake system for SAE Level 2.

[0204] The new inverter configuration according to the invention, described in detail below (called "RSP-4Q inverter"), allows the realization of an inverter with only 18 switching elements (6 connection switching elements in total and 12 supply switching elements), which allows the operation of the electric motor to be switched from a series circuit of phases to a parallel circuit or vice versa. In the parallel circuit, 12 supply switching elements are active, whereas in the series circuit, 6 connection switching elements and 6 of the 12 supply switching elements are active. In this case, "active" means that the switching elements in question are timed, while the other switching elements are, for example, idle.

[0205] Additionally, depending on the failure of one or more operating elements, a switchover from a series circuit to a parallel circuit or vice versa takes place. Operating elements here are understood to mean, but are not limited to, switching elements, such as supply switching elements and connection switching elements and / or coils of individual phases. This arrangement makes it easy to continue operating the electric motor by switching from a series circuit to a parallel circuit in the event of a failure of one or more operating elements.

[0206] An inverter, as shown in Figure 7b, for example as described in WO 2021 / 179980, is connected to an electric motor 4 with six phases U, V, W, U', V', W', but the inverter is only illustrated diagrammatically by its circuit and its terminals.

[0207] Each phase U, V, W, U', V', W' has at least one coil 6. Two phases U, V, W, U', V', W' are each grouped together in a strand. The strands are illustrated in FIG. 7b as a circle of phases forming each strand, by way of example. Each one of the two phases U, V, W, U', V', W' of a strand is electrically rotated by 180° with respect to the other phase U, V, W, U', V', W' of the same strand 8, i.e. is connected inverted. The respective inverted connected phases U', V', W' are shown with lines to distinguish them from the other phases U, V, W. Thus, in this embodiment, phase U' is an inverted phase with respect to phase U, phase V' is an inverted phase with respect to phase V and phase W' is an inverted phase with respect to phase W.

[0208] The inverter further comprises six switching units 10, indicated by dashed rectangles. One switching unit 10 is assigned to each of the phases U, V, W, U', V', W'. Furthermore, each switching unit 10 of two phases U, V, W, U', V', W' of one strand forms one switching module. In the figure, each switching unit 10 forms one switching module, so that the inverter according to the invention shown in FIG. 7b comprises three switching modules. Each switching unit 10 is connected to means for applying a supply voltage to the individual phases U, V, W, U', V', W'. For this purpose, each switching unit 10 comprises two supply switching elements 16, which are configured as MOSFETs in the example.

[0209] Depending on the operating mode of the electric motor 4, each of the two phases U, V, W, U', V', W' of one strand are connected in parallel or in series with one another. For this purpose, the inverter 2 comprises a control unit which is arranged to drive and control the supply switching element 16 and the connection switching element 20.

[0210] Additionally, the inverter 2 comprises a fuse unit (not shown in FIG. 7b), also referred to as a "circuit-breaking module", which is arranged between the electric motor 4 and the inverter 2. The fuse unit comprises switching elements, not shown, which are arranged to isolate the electric motor 4, preferably galvanically, from the inverter 2 in the event of an error.

[0211] For simplification, the RSP-4Q inverter described herein is used for the closed-loop control strategy with torque boost as explained in Fig. 7a, but in other embodiments other inverters that allow switching of inductance during operation, for example inverters that switch between delta and star circuits or other inverters as used for example in DE 112018000733 A1 or DE 112018001213 A1, may also be suitable.

[0212] FIG. 8 shows a retraction-resistant, bidirectional inlet / outlet valve MV 1 which is used to realize the pressure control function in the EHB brake system of FIGS. 6a to 6d or in the axle pressure regulator shown in FIGS. 9a and 9b. 2k An advantageous embodiment of is shown.

[0213] FIG. 8 shows a special valve MV , which is required for the above-described embodiment and which functions reliably in both flow directions. 2k In other words, the function of the valve is to allow a large amount of flow, e.g. 100 cm 3 / s~120cm 3 / s or even large pressure differences across the valve, for example 160 bar to 220 bar. 2k is guaranteed not to be closed automatically.

[0214] Valve MV 2k has essentially the typical structure of a solenoid valve with a solenoid circuit EM1 that includes an armature 6, a valve adjustment element or valve plunger 7 and a valve seat 8 as well as a return spring 13. If the force application device, which is formed by the solenoid circuit EM2 in FIG. 8, is designed accordingly, the return spring can be omitted.

[0215] The electromagnetic circuit EM1 generates a strong progressive force characteristic FM1 over the stroke h, and the return spring 13 generates a progressive return force F over the stroke h for the return of the armature. RF Form.

[0216] The armature 6 is coupled in the left-hand view of Fig. 8 to a second force-generating element forming a force application device. This consists of a second electromagnetic circuit EM2 with an armature 6a and a switchable force F M2 is the force F in the first electromagnetic circuit EM1 M1 acts to counteract.

[0217] A cheaper variation could also use a permanent magnet circuit as a passive force applying device having a small permanent magnet 9 with a pole plate 10 .

[0218] Force action F M2 is F M1 and acts with a relatively high force upon opening of the valve with a large drop in the desired force over the stroke h.

[0219] force F M2 (see FIG. 8b) is large enough to still provide the normal armature return when it reaches its stroke and can therefore optionally replace the normal return spring 13.

[0220] Figure 8c shows the current intensity and F M2 Power source F as a function of M1 The interaction is shown in a permanent magnet.

[0221] At the valve seat in the closed valve position, a pressure difference P2-P1 acts with a force FP in the direction of the valve opening if pressure P2 is greater than pressure P1.

[0222] At the valve seat in the open position, the volume flow Q through the valve creates the above-mentioned hydraulic pressure F which, if no countermeasures are taken, could destroy the valve. H However, solenoid valve MV 2k Depending on how the pressure supply DV and the wheel brake cylinder RZ are connected, the pressure increase P auf and pressure reduction P abThis is based on the pressure closed loop control with pressure supply and wheel brakes shown in the following figures 9a and 9b.

[0223] When the solenoid valve is in the open position, when flow occurs through the valve, a force F is generated from the valve armature terminal (14) to the valve seat terminal (16). H acts according to the magnitude of the volume flow rate Q based on the Bernoulli effect. If the volume flow rate Q is very high, for example, if the pressure difference is large, this is because the valve simply acts against the flow force F H This means that the valve is pushed in by the valve. As a result, the valve closes and can no longer open.

[0224] In order to avoid such effects, the force F of the force application device M2 F H , preventing the valve from closing under the large pressure differentials that can occur during operation of the braking system.

[0225] Preferably, the additional force F in the open position of the valve M is maximum, which can be achieved, for example, by a permanent magnet circuit, and acts over the entire stroke range so that, when flowing with a volume flow rate Q, the valve is always returned to its open position, regardless of the valve position, i.e., especially in the half-closed state, and the return force F of the valve spring is RF Support the following:

[0226] In a corresponding design, the valve return spring 13 can also be omitted.

[0227] In addition, when the valve is energized, the electromagnetic circuit E M1 By operating the primary valve force F M1 is the sum of the two forces (F M2 +F RF ) so that the valve can be closed by energizing it.

[0228] Here, large volume flows occur if the wheel brakes, which are typically used in wheel valve configurations with inlet and outlet valves (see the embodiment shown in Fig. 6a-6d), are connected to the changeover valve via the armature terminals, and at that moment the power supply to the ECU or the brake system fails, thus preventing the pressure drop via the outlet valve, because such an outlet valve is closed by the pressure difference and the residual pressure is applied by the return force F of the valve spring. RF The retraction of the valve can also occur due to very high pressure gradients, for example when the pressure is reduced by a very rapid backward movement of the piston of the pressure supply unit.

[0229] A retraction-resistant valve configuration is also important when the pressure supply device is connected to the armature terminal, as shown, for example, in Figures 9a and 9b, and also when the pressure is increased very quickly by the pressure supply unit, e.g. during automatic emergency braking (AEB) or in multiplex methods, by pressure characteristic control via volume closed-loop / volume open-loop control of the pressure supply device instead of pressure characteristic control via volumetric flow control of preload control and PWM control of the inlet valve.

[0230] The retraction action can be limited by a pressure difference limiting part of the closed loop control of the pressure supply unit or preferably by a throttle not shown in the drawing, which is installed in the hydraulic line upstream of the armature terminal of the valve connection.

[0231] Another option is to open the valve when the pressure difference is large, which allows the hydraulic pressure F to act by the Bernoulli effect. H and thus the force applying device F M2 The advantage of this arrangement is that an overpressure protection valve is placed in the hydraulic parallel circuit leading to the switching valve, so that no overpressure protection valve is required. This simplifies the valve design, but limits the pressure change dynamics via the hydraulic pressure supply.

[0232] If the braking torque change is controlled in parallel in a closed loop via the traction motor, this is not necessary since the demands on the dynamics of the hydraulic brake system are smaller. In this case, a standard valve can be used without additional force devices and without throttling or overpressure protection valves.

[0233] In the event of a wheel circuit failure, the wheel circuit can be separated by closing the inlet valve SV, which is arranged between the wheel brakes and the pressure supply. A hydraulic brake system with n wheel circuits does not therefore have to be operated by the wheel circuits, i.e. by n-1 wheel circuits, i.e. instead of a four-way brake system closed-loop control, for example, it can be operated by three. This means that in the case of a wheel circuit failure, a very high deceleration can still be achieved after closing the inlet valve SV, and furthermore, the yaw moment closed-loop control or ESP function with three wheel brakes can be maintained. If an electric motor is available in the wheel circuit in which the failure occurs, it can take over the braking torque control of the failed wheel brake, so that the four-way braking torque control can be maintained without or only slightly limited, for example by the maximum braking torque of the traction motor.

[0234] The valve plunger 7 can have a special shape that can provide a counter force by the hydraulic flow forces and reduce the retraction force.

[0235] FIG. 8c shows the electrical actuation of the valve via a current i. The current strength i1 is F M1 F M2 In this case, the current can be varied depending on the hydraulic pressure difference P2-P1 through the valve at the closed position of the valve under the current intensity i2. M2 is within the normal spring force range in that position for the reasons discussed above, the valve may also be actuated by open or closed loop control of the current, for example.

[0236] A differential force is applied to hold the valve in the closed position. F V,zu =F M1,zu -F M2,zu must be greater than the force FP resulting from the pressure difference P2-P1 across the valve in the closed position.

[0237] 9a shows the construction of a pressure regulator in the form of a piston-cylinder unit driven by an electric motor via a transmission, to which two wheel brakes R1 and R2 and, optionally, a further hydraulic consumer Vx are connected via hydraulic lines. The further hydraulic consumer Vx can be a further wheel brake or a further hydraulic consumer, for example a hydraulic piston of a clutch or a hydraulic power steering or other actuation piston of a vehicle axle. The pressure regulator is preferably connected to a valve device with a reservoir tank VB.

[0238] The pressure regulator is preferably connected to two control units ECU1 EHB and ECU2 EHB , where current sensors i / U and angle sensors a / U are provided which are preferably configured equally redundantly and are used for highly precise PPC pressure open-loop control or pressure closed-loop control via the piston position or current.

[0239] At the output of the pressure supply, a pressure sensor p / U is preferably provided, which is used primarily for calibration purposes, but the pressure closed-loop or pressure open-loop control can also be carried out without a pressure sensor if the relationship between the EBS braking torque and the current or the piston position is formed in another way, for example by using an acceleration sensor or by comparison with the braking torque or the vehicle deceleration by the braking torque of the electric traction motors TM1-TM4.

[0240] As used herein, the solenoid valve is referred to as "MV 2kIn this case, a bidirectional inlet / outlet valve called the MV 2k The valve is actuated via a solenoid valve in such a way that both pressure build-up and pressure reduction are possible, with the pressure change taking place with particularly high dynamics, i.e. above 1000 bar / s, preferably above 2000 bar / s. The valve must be designed to be draw-in resistant according to the system specifications, i.e. according to the required maximum pressure and maximum volumetric flow rate.

[0241] In this case, preferably a solenoid valve is used which comprises a first soft iron magnet circuit EM1 and a second permanent magnet circuit EM2 as shown in Figs. 8 to 8c.

[0242] Alternatively, a modified inlet valve of the standard ESP unit can be used with the MV 2k It is also possible to use a solenoid valve of the de-energized open type without the second permanent magnet circuit EM2 and with a standard valve opening cross section and a 6 mm magnetic core diameter, which in a typical design can be configured to be retraction-resistant as well, in particular on the basis of the relatively small retraction forces during pressure changes with the maximum pressures and thus the maximum pressure gradients occurring in the driving dynamics system of the invention.

[0243] The inlet valve of the ABS / ESP unit is MV 2k When used as a valve, the inlet valve must be designed with a stronger electromagnetic circuit, for example with a larger armature and / or a larger return spring, depending on the pressure differential and rate of pressure change.

[0244] Alternatively, the pressure gradient and / or pressure difference can be limited via software control of pressure increases so that dynamic pressure increases do not result in solenoid valve retraction.

[0245] Based on the fact that the pressure range during closed-loop control of the driving dynamics system described herein is smaller than in the case of a standard brake system and, in addition, the braking torque can be generated via an electric traction motor, the MV 2K The demands on the valves are less than in standard braking systems.

[0246] Music Video 2k A peculiarity of the valve, regardless of the variant selected, is that the solenoid valve is configured without a check valve connected in parallel or that no check valve is arranged in parallel in the hydraulic lines in the hydraulic connections between the wheel brakes R1, R2 or the hydraulic consumers Vx and the pressure supply device.

[0247] This aims to keep the pressure in one wheel brake constant while the pressure in another wheel brake is changed. This is a major difference from a standard brake system, in which the pressure in the wheel brake can only be maintained by preloading via a pressure regulator, and in which the degree of freedom in pressure control is significantly limited and, in the case of a wheel circuit failure, it is not possible to distinguish whether the solenoid valve, the check valve or the hydraulic output is the cause, making it extremely difficult to diagnose a wheel brake failure.

[0248] Music Video 2k If valves are used, the wheel brakes can be reliably isolated from the pressure supply, regardless of the cause of the failure. Thus, a changeover from an m-channel electrohydraulic brake system EHB to an m-1-channel brake system is possible. In FIG. 9a, for example, a changeover is made from a 2-channel EHB with 2 wheel brakes to a 1-channel EHB or from a 3-channel EHB with Vx to a 2-channel EHB.

[0249] In the case shown in Figure 6a, it goes from 4 EBS to 3 EBS, and in Figure 6b it goes from 3 EBS to 2 EBS.

[0250] One feature of this first configuration is that MV 2k The valve seat is connected to the wheel circuit and the armature chamber is connected to a pressure regulator.

[0251] This structure allows an innovative closed-loop pressure control with bidirectional inlet / outlet valves and forward / reverse movement of the piston of the piston-cylinder unit to be realized by open-loop control of the current or the piston and simultaneous pressure reduction open-loop controlled by the pressure gradient. The pressure build-up is carried out continuously in one embodiment in a known multiplex manner. Alternatively, the dead time of the pressure build-up can be avoided by a braking torque gradient by the electric traction motor, which is possible if an electric traction motor is present for the individual drive of each wheel. Alternatively, the braking torque structure can also be carried out via the traction motor of one axle, which is particularly possible if both wheels have an equal braking torque rise for two wheels of one axle.

[0252] If a pressure increase is required at the same time and the electric traction motor is not used for assistance, the pressure increase here can be achieved simultaneously by time control of the valves, i.e. a variable preload is set by the pistons and one valve closes earlier than the second valve. Pressure reduction is simultaneously achieved in several wheel brakes via open-loop piston control, with the aid of a pressure-volume characteristic curve and a PWM open-loop or current closed-loop control of the valves, i.e. a variable flow cross-section is adjusted by the current so that different pressure reduction gradients can be achieved.

[0253] Such closed loop control further includes: PCC-Gen2-VI (Piston Pressure Control 2.Generation mit Ventilanschluss V1 (Second generation piston pressure control using valve terminal V1): Valve seat inlet / outlet valve MV of wheel brake 2k ) is also called.

[0254] FIG. 9b shows a MV driven by an electric motor through a transmission mechanism. 2k Equipped with a piston-cylinder unit equipped with a switching valve, MV 2k The valve seat of the switching valve is connected to a hydraulic line leading to a pressure regulator, unlike in FIG. 9a, and the MV 2k A pressure regulator construction is shown in which the armature chamber of the changeover valve is connected to the wheel brakes. In addition, an optional outlet valve is provided.

[0255] With such a structure, the second variation of the pressure closed loop control PPC-Gen1-V2 can be realized, in which the pressure closed loop control is performed by a bidirectionally acting inlet / outlet valve MV 2k and forward and backward movement of the piston of the piston-cylinder unit via open loop control of the current or piston, and pressure increase simultaneously controlled by the pressure gradient. MV 2k The valve design of the valve is similar to the configuration shown in FIG. 9a and is therefore transferable, as well as the PPC pressure closed loop control or pressure open loop control and preferably redundant electronic circuit ECU1 EHB , ECU2 EHB Motors equipped with sensors a / U and i / U can also be used.

[0256] The pressure reduction is, in one embodiment, performed in a known multiplex manner with a time delay Δt MUX or continuously via time control of the outflow valve, as is known from conventional ABS systems.

[0257] In contrast to the prior art, pressure reduction can be performed simultaneously in the wheel circuit (R2) and on the basis of a pressure-volume characteristic curve using piston control via the inlet / outlet valve, while in the second wheel circuit (R1') via the outlet valve. This allows the time delay Δt MUX can be avoided.

[0258] Thus, in critical driving situations, for example at high μ or μ jumps, the pressure can be reduced very quickly. In other control situations, for example in the case of low μ, i.e. on ice and snow, the control can be carried out in a known multiplex manner. By combining pressure reduction methods, therefore, very short stopping distances can be achieved in all driving situations.

[0259] The combination of pressure reduction through the outlet valve and pressure reduction through the inlet / outlet valve creates a draw-resistant MV designed for the pressure difference and volumetric flow rate. 2k It has the further advantage that no valves need to be used, because when the pressure is reduced, the MV 2k This is because there is no need to have a high flow rate through the valve, since a pressure reduction with a high pressure gradient takes place through the outlet valve.

[0260] Furthermore, M.V. 2k The valve is further less loaded during pressure reduction, because the electrohydraulic brake unit EHB described above is designed for a maximum pressure of up to 140 bar for the driving dynamics system, and the valve does not have to be pressure-resistant to 160 bar to 220 bar as shown in FIG. 8a. In this embodiment, therefore, a modified standard inlet valve of the ESP unit can be used, which has a typical valve opening cross section, but does not have a non-return valve connected in parallel. The advantages of not having a parallel non-return valve have been described above with reference to FIG. 9a and apply analogously to FIG. 9b.

[0261] In advantageous combination with the outflow valve, the pressure can be quickly reduced in all driving situations, which also significantly reduces the demands on the dynamics of the drive motor of the pressure regulator. In closed-loop control with the MUX method in many operating states, the hydraulic brake circuit can be operated mainly in a closed brake circuit. This makes it possible to omit the critical additional pumping of hydraulic fluid in the control operation of the prior art (which is controlled according to the method described in EP 2580095 and is typical for an open system according to DE 102018212905 A1). This means that the additional pumping of volume in an open system is considered to be increasingly important, since interruptions of time of more than 100 ms can lead to critical driving situations.

[0262] Furthermore, the brake system embedded in the driving dynamics system described herein can take on more functions beyond pure ABS control operation, for example further braking torque interventions such as torque vectoring interventions, which can eliminate hydraulic volumes in the open circuit.

[0263] Further, the MV according to the present invention 2K If the valve is used as a changeover valve, it is possible to diagnose faults in the wheel circuit as in the case described with reference to Fig. 9a and furthermore to operate the wheel circuit even under small leaks, which is not possible with prior art systems with parallel-connected check valves.

[0264] This type of control is here represented by PPC-Gen2-V2 (Piston Pressure Control 2nd generation generator with valve terminal V2: valve seat inlet / outlet valve MV in the pressure supply section) 2k ) is called.

[0265] Solenoid valve MV with pull resistance 2kAlternatively, a standard inlet valve of the ABS / ESP unit can be used, which is designed, for example, with a strong solenoid circuit and / or a strong return spring, depending on the pressure difference and the pressure change rate. Due to the fact that the pressure area of ​​the closed-loop control of the driving dynamics system described here is smaller than in the case of a standard brake system, the demands on the solenoid valve are smaller.

[0266] As an alternative to a piston-cylinder unit with inlet and outlet valves, simple pumps can be used, for example a two-piston pump according to the prior art in ABS pumps or a gear pump according to WO2021005151. In a two-piston pump, the pressure reduction control is carried out via the outlet valve, and the pressure increase is controlled via preload and PWM control of the inlet valve. If a gear pump is used, the same degree of freedom as in the case of a piston-cylinder unit is obtained, since the pressure can be selectively formed via the outlet valve or by changing the direction of rotation via the gear pump. This embodiment has cost advantages, but the gear pump has disadvantages in the accuracy of the braking torque control due to leakage.

[0267] FIG. 10 shows an advantageous “Architecture II” of a driving dynamics system for an E-axle, in which several brake units act on the front and rear axle respectively.

[0268] The brake unit consists of traction motors TM1, TM2, TM3 for the wheel brakes, and a hydraulic pressure regulator EHB. HA , E.H.B. VA and / or EMB modules. The central control unit is responsible here for controlling the braking torque and transmits the desired signal to the axle control unit S-ECU VA , S-ECU HA This, similar to "Architecture I", preferably includes the following functions: (A) Base brake with thermal and energy flow management of the traction motor; · (B) AEB emergency braking with electronic brake force distribution (EBV); (C) Regenerative braking on multiple axles; (D) ABS control with base braking torque assistance and / or common braking torque control; (E) Braking behavior in the event of a malfunction of the electrohydraulic brake units EHB-Z, EHB-VA; (F) Yaw moment intervention or braking torque intervention separately for each wheel; and / or (G) Wheel-specific braking torque intervention for wheel-specific regenerative braking is realized.

[0269] The driving dynamics system transmits setpoint values, which in particular include the braking torque or the braking pressure. For certain functions (e.g. functions (C), (F), (G) mentioned above), setpoint signals for the pressure open-loop or pressure closed-loop control, e.g. control signals for solenoid valves for functions such as the switching duration of the opening time, the PWM frequency or alternatively the current profile when a pressure change occurs by throttling the valve cross section, and / or preloads for the pressure supply devices for pressure build-up or pressure reduction are also predefined.

[0270] Furthermore, M-ECU DOMAENE is the interface to the control unit or the domain M-ECU for autonomous driving DOMAENE , and can evaluate further information that is useful for an effective and predictive closed-loop control, such as camera information about the road properties (snow, ice, rain) or information about the surrounding environment (distance from occupants and / or other vehicles).

[0271] With reference to Fig. 11a, a first embodiment of an axle module is described, in which an electric motor brake unit EMB1, EMB2 is provided for each wheel and further an electric traction motor TM1 for the axle.

[0272] The axle control unit S-ECU-Achse communicates with the electric motor brake units EMB1, EMB2 and the electric traction motor TM1 and transmits corresponding setpoint signals so that the braking torque is preferably simultaneously adjusted by means of the electric motor brake units EMB1, EMB2 and the traction motor TM1, in which case the braking torque preferably acts additionally on the wheels also in closed-loop control operation.

[0273] Here, for example, by the traction motor TM1, a base braking torque is generated, which preferably reduces the braking torque amplitude of the EMB module (see the above explanation with respect to FIG. 5). Furthermore, the base braking torque of the traction motor TM1 can also be reduced simultaneously with the EMB braking torque of the wheel brakes, so that a higher braking torque gradient can be achieved. This is particularly important in critical driving situations, such as for example μ-jumps (see the above explanation of the control situation with respect to FIG. 5b). This can furthermore advantageously be used for downsizing the EMB module with a small maximum force and a small power output of the drive motor of the EMB.

[0274] A further embodiment is described with reference to Fig. 11b, in which an electrohydraulic pressure regulator EHB is combined with an EMB module in one axle module, the pressure regulator preferably being configured according to Fig. 9a and 9b, allowing individual closed-loop control for each wheel.

[0275] This allows individual adjustment for each wheel, selectively, either by the EMB module or by the electrohydraulic brake unit EHB.

[0276] This allows maximum flexibility in pressure control.

[0277] Furthermore, redundancy in the pressure control for each wheel individually is possible, as required for example for SAE levels 4-5, so that the ABS control function can be realized redundantly and also by two different construction forms of the brake torque regulator, which is particularly advantageous with regard to the realization of redundancy requirements.

[0278] Such a configuration is particularly suited to the front axle of autonomous vehicles, which must meet higher demands than the rear axle, for example with regard to steerability and a greater influence on braking distances.

[0279] Such an axle configuration can also be used to simplify steer-by-wire systems that typically have two steering actuators, which are then equipped with a 2x3-phase winding. In this way, steering with braking torque can be simplified, since reliable redundant steering with braking torque can be guaranteed. This results in a cost reduction of up to 100 euros in steering.

[0280] Alternatively, a pressure regulator with only one hydraulic line for the two wheel brakes is also conceivable, but this is not shown in FIG. 11b. For this purpose, as an alternative to the piston-cylinder unit, a simple rotary pump in the form of a gear pump with pressure build-up and pressure reduction is also possible. In this embodiment, a braking torque can be applied for each axle. Here, the hydraulic pressure regulator acts to assist in the closed-loop control in the same way as a traction motor, but deceleration up to the locking pressure can also be achieved due to the lack of power limitation. This allows an ABS function for each axle, which is absolutely sufficient for the regulation of the rear axle when individual control for each wheel is realized at the front axle.

[0281] If the system of FIG. 11b is provided for the rear axle and the system of FIG. 11a is combined with the front axle, a three-channel ABS operation and yaw moment closed-loop control can be achieved.

[0282] With reference to Fig. 11c a further embodiment is described having an electrohydraulic brake unit EHB and two electric traction motors TM1 and TM2, one traction motor each for one wheel.

[0283] Alternatively, the electrohydraulic brake unit EHB is configured for individual control for each wheel as shown, however, the concept is that the electrohydraulic brake unit EHB is only one line.

[0284] With this configuration, advantageously the rear axle of the vehicle is equipped with an electrohydraulic brake unit EHB, which is used for redundancy purposes for the ABS and for yaw moment control for stability and steering interventions. The ABS is controlled at low μ via the traction motor and assisted by the EHB, whereas the ABS at high μ is controlled by the EHB and assisted by the traction motor. Anti-slip control is exclusively carried out via the traction motors TM1 and TM2. Advantageously, such an axle is equipped with inexpensive drum brakes.

[0285] With reference to Fig. 11d a further embodiment is described in which the traction motor TM1 is combined with an electrohydraulic brake unit EHB, said variant being equivalent to the embodiment shown in Fig. 11a with the difference that the electric motor brake unit EMB is replaced in its function by the electrohydraulic brake unit EHB.

[0286] FIG. 12 shows a typical brake unit 1 box (curve 1210), an ESP standard with storage chamber (curve 1220), an electric traction motor (curve 1240), an electric traction motor with RSP-4Q inverter (curve 1250), as well as a high braking torque gradient design for an exemplary maximum speed of 200 km / h, preferably an MV with retraction resistance. 2k The maximum braking torque gradient depending on the vehicle deceleration based on an exemplary design of a pressure regulator (curve 1260) with PPC-Gen2-V1 or PPC-Gen2-V2 pressure control using a valve is shown.

[0287] Furthermore, a curve corresponding to "MUX2.0" is shown (curve 1230), where MUX2.0 compiles together the second generation multiplex methods described in this document, such as pressure regulation PPC-Gen2-Vl and PPC-Genl-V2 (see the explanations for Fig. 9a and Fig. 9b). In particular, retraction-resistant valves are used in this system, and a distinction is made between different valve terminals and pressure control methods. In PPC-Gen2-Vl, the valve seat is connected to the wheel brakes, and in PPC-Gen2-V2, the valve seat is connected to a pressure supply unit. In both methods, the valve has a bidirectional flow and in the pressure change direction the pressure is changed via volume control. In the other pressure change direction the pressure is optionally throttled by controlling the opening cross section of the valve or is changed only via time control of the valve. Such a second generation multiplex method differs from the first generation multiplex method (MUX1.0) in that in the MUX1.0 method, the pressure is changed exclusively by volume open / closed loop control in the two pressure change directions. In addition, a pressure reduction via at least one outlet valve in the wheel brake is realized. Overall, this results in a higher pressure change gradient than when using one box and ESP.

[0288] Furthermore, three regions I-III are defined.

[0289] Low deceleration Area IIn the basic scheme, the electric motor brake unit EMB and the electric traction motor can achieve a particularly high braking torque gradient. The standard ESP system with the storage chamber has the lowest gradient, because the counter pressure acts in the storage chamber, whereas the one-box brake system reduces the pressure in the reservoir tank and therefore has an advantage. Therefore, in the region I, which is typically related to deceleration with ABS control or normal ACC braking operation, for example on snow and ice, the electric motor brake unit EMB or the traction motor is advantageously used for the braking torque control.

[0290] Area III Similarly, when there are high decelerations in the axial direction, an electrohydraulic system (preferably a pressure regulator with PC-Gen2 closed loop control, one box) has great advantages and is preferably responsible for the ABS closed loop control.

[0291] Located between Region I and Region III Area II In this case, a sufficient braking torque gradient can be achieved by all the brake units described above. Advantageously, in this case, a first braking torque regulator with a small braking torque gradient supports the ABS control with a constant braking torque, while the ABS control is taken over by the more dynamic pressure regulator.

[0292] By adding the braking torque gradients of the two braking torque regulators respectively, a high braking torque gradient can be guaranteed over the entire deceleration range if the additional braking torque is linearized over the entire deceleration range. Ideally, the favorable characteristics are advantageously utilized for downsizing the brake unit. Thus, smaller drive torques and powers can be used for EMB and EBS motors and / or smaller control valves can be used. Especially in such cases, a low-cost EHB pressure regulator with a trapezoidal spindle is feasible, which is only suitable for the lower pressure range due to the higher pressure-based spindle load.

[0293] If the pressure regulators are driven sequentially by the MUX control, the dead time in the control cycle can be reduced by the braking torque intervention of other units, so that the MUX control, which lost its importance due to its disadvantages in extreme situations (e.g. in the case of high μ), regains importance. This has the special advantage that the brake system is completely closed and the closed-loop control can be mapped via a mathematical model. In this case, no laborious pressure estimation models and application work is required for the calibration of the open ABS system. Automatic application is therefore also possible.

[0294] With reference to Fig. 12a it is exemplarily explained how the target braking torque for the wheel brakes of the front axle of the vehicle is obtained by the control unit. Chassis-control The vehicle model implemented in the M-ECU contains, for example, modeling data of the weight distribution, friction values ​​of the road surface, tire state and brake pressure action on the vehicle deceleration. VA The following values ​​are input to the right and left front wheels: soll,VR ,M soll,VL , vehicle V Fzg , the speed of the right and left front wheels V VR ,V VL , the differential torque ΔM between the right and left front wheels soll,VR ,ΔM soll,VL , as well as the friction value of the roadway are passed on.

[0295] Front axle control unit M-ECU VA contains, inter alia, an Mn characteristic map of the traction motor TM, which shows the relationship between the deceleration achieved by the traction motor and the vehicle speed or the rotational speed of the traction motor, and another characteristic map which shows the relationship between the achievable braking torque gradient and the achievable vehicle deceleration for the brake unit or the traction motor.

[0296] Based on these data, the control unit M-ECU VAis the target torque M for the first traction motor and the second traction motor of the front axle soll,TM1 ,M soll,TM2 , the target torque M for the electromechanical brake units of the first and second wheels soll,EMB,R1 ,M soll,EMB,R2 and the target torque M of the electrohydraulic brake unit for the first wheel and the second wheel soII,EHB,R1 ,M soII,EHB,R2 The procedure here is adapted to which brake units are actually available.

[0297] In this case, from these values, the target braking torque M soll,Brems,VR ,M soll,Brems,VL is obtained.

[0298] The same procedure can be performed for the rear axle as well, or for all wheels of the vehicle.

[0299] An advantageous "architecture III" of a driving dynamics system for wheel modules is described with reference to Fig. 13, in which two brake units act on each wheel. As brake units, for example, traction motors TM1, TM2, TM3, TM4 and electric motor brake unit EMB modules EMB1, EMB2, EMB3, EMB4 can be used for the wheel brakes.

[0300] The central control unit is responsible for controlling the braking torque and sending the target signals to the individual wheels or axle control units (S-ECUs). Rad1 , S-ECU Rad2 , S-ECU Rad3 , S-ECU Rad4 Send to.

[0301] This, like architectures I and II, preferably includes the following features: (A) Base brake with thermal and energy flow management of the traction motor; · (B) AEB emergency braking with electronic brake force distribution (EBV); (C) Regenerative braking on multiple axles; · (D) ABS control with basic brake torque assistance and / or common brake torque control; (E) Braking behavior of electric motor brake units EHB-Z, EHB-VA in case of failure; (F) Yaw moment intervention or braking torque intervention separately for each wheel; and / or (G) Wheel-specific braking torque intervention for wheel-specific regenerative braking is realized.

[0302] To achieve this function, the braking torque is divided between the electric traction motor and the EMB according to the characteristic map, in particular the braking torque gradient as shown in FIG. 12, the deceleration of the vehicle, and in this case, unlike other configurations, the braking torque modulation is preferably performed by the electric motor brake unit EMB in all driving states, and only a basic braking torque is generated via the electric traction motor of each wheel, which is used in particular for downsizing the electric motor brake unit EMB. This is preferably used when the wheel brakes are heated. In the event of a failure of one brake unit, the control action is taken over by the respective other brake unit, resulting in a fully redundant control function at all wheels, possibly with a limitation of the maximum achievable deceleration.

[0303] An embodiment of the architecture here will be described with reference to Fig. 13a. In the wheel modules, electromechanical brakes EMB (EMB1-EMB4) are combined with electric traction motors (TM1-TM4), so that each wheel module forms a module, each of which is controlled by a wheel module controller (M-ECU). Rad1 ~M-ECU Rad4The wheel module controllers then synchronize the torque control of the electric traction motors in time and distribute the braking torque differently between the EMB and the traction motor TM depending on the driving situation, for example depending on the friction value or the speed.

[0304] Preferably, the traction motor and the EMB are each connected to a further control unit (ECU EMB ,ECU TM ), which control units include, in particular, the output stage of the inverter and the motor control, and operate at a faster clock time, whereas the wheel module control unit M-ECU Rad is preferably mapped with a decision mechanism as well as a characteristic map.

[0305] Furthermore, the wheel module control unit (M-ECU Rad1 ~M-ECU Rad4 ) is the central control unit (M-ECU DOMAENE ), in particular the wheel rotation speed v R1 ~v R4 And in particular the further sensor signals S1, S2, Si are read in.

[0306] Wheel module control unit (M-ECU) Rad1 ~M-ECU Rad4 ) is the wheel rotation speed v R1 ~v R4 and the sensor signals S1, S2, Si. These components are further connected to a central control unit (M-ECU DOMAENE ) functions can be performed redundantly.

[0307] This allows for individual control for each wheel, selectively, by the EMB module or the traction motor. This allows for maximum freedom in pressure control and also allows for redundancy in individual pressure control for each wheel, as required, for example, for SAE levels 4 to 5. In particular, the ABS control function can be realized redundantly and even by two different construction forms of the braking torque regulator, which is particularly advantageous with regard to redundancy requirements. Thus, even in the event of a failure of one wheel module, a highly reliable and reliable closed-loop control can still be realized with three wheel modules, with the possibility of short braking distances and yaw moment closed-loop control. In the event of a failure of the electric motor brake unit EMB or the traction motor in one wheel module, the respective other non-faulty component takes over the closed-loop control of the braking process.

[0308] There are various variations in the design. a) Since the electric motor brake unit EMB is designed to achieve a locking pressure, in the event of a traction motor failure, the vehicle can still brake at maximum deceleration via the electric motor brake unit EMB, but without a large reserve for fade (typically 100%), i.e. the electric motor brake unit EMB only has a small reserve, for example 20% to 40%, in addition to the maximum braking torque without heating. b) The electric motor brake unit EMB and the electric traction motor TM are designed to achieve maximum deceleration by combining the braking torques of EMB and TM and to design the friction brake according to the maximum braking torque of the electromechanical brake unit EMB. Furthermore, as explained above in relation to "Architecture I", appropriate precautions and control strategies are required so that braking via the regenerative braking torque of the traction motor does not lead to damage to the battery, especially in the fully charged state. Here, strategies include (1) feedback to the battery up to the limit of power consumption, (2) field-oriented current control of the electric motor (Id / Iq current control) in which the energy is dissipated inside the motor, (3) dissipation in other ways of the energy gained by the electric traction motor in generator operation, or (4) the use of an electric intermediate storage device designed for pulsed output, for example a supercapacitor.

[0309] Variant b) is the preferred design because it offers the greatest potential for cost and weight reduction, although in the first implementation scenario of the technology, variant a) may be more advantageous in terms of risk minimization.

[0310] The two above mentioned variants a) and b) provide sufficient safety for SAE level 5, because in the event of failure of a component of the wheel module as well as in the event of failure of the entire wheel module, the vehicle can be decelerated with high vehicle stability and even in ABS operation, which only results in loss of braking distance at high speeds and when decelerating.

[0311] The systems, particularly the driving dynamics systems, vehicles and methods described herein enable significant cost reductions in the core components of vehicle braking and steering. Additionally, significant weight savings can be achieved, resulting in further cost reductions.

[0312] By optimally utilizing the capacity of the electric traction motor or the capacity of regenerative braking with the electric traction motor, the dissipative brake system can be dimensioned smaller, since it only has to further generate a small portion of the total braking torque, and therefore the problem of fading on excessive heating of the friction brakes can be reduced as well.

[0313] A: AD Level 2 For example, as described above for FDS variant A1, heating of the wheel brakes can be minimized if the basic braking function (function a) is optimized by the driving dynamics system and central control and the fade strategy shown in Figure 3, i.e., for example, 51% is regenerative braking by the traction motor on the front axle and 71% is regenerative braking on the rear axle.

[0314] This has two positive effects in terms of costs: on the one hand, the brake system can be designed for a comparatively lower pressure, which reduces the costs of the electrohydraulic brake unit EHB, and on the other hand, the base brake can be designed to be significantly weaker, which can be achieved, for example, by smaller brake discs, smaller brake jaws and also cheaper materials. Cheaper drum brakes can therefore be used on both the front and rear axles.

[0315] In the case of the FDS variant A2, for example, in order to simplify the electrohydraulic brake system according to Fig. 6b, the traction motor on the rear axle can be configured in such a way that the torque can be generated separately for each wheel by a traction motor with a torque vectoring module or preferably by splitting the motor power of 130 kW into two electric traction motors TM1, TM2 of 65 kW each. The latter embodiment with two motors is advantageous, since the dynamic braking torque at the two wheels can be changed independently of each other.

[0316] Furthermore, as described above, if the braking torque is controlled synchronously via the electric traction motor and the electrohydraulic brake module EHB via the driving dynamics system, in particular where a brake unit forms a basic braking torque to which a second brake unit forms an additively controlled braking torque (control strategy of FIG. 5), the costs and weight of the system can be further significantly reduced.

[0317] On the one hand, in particular with the embodiment of FIG. 6a, the cost of the electrohydraulic brake unit EHB can be reduced by fewer and less expensive valves, as well as a lower maximum pressure and a smaller volume. Here, instead of a ball-screw transmission, a less expensive trapezoidal spindle can be used. Furthermore, drum brakes can be used both on the front and on the rear axle.

[0318] In the case of the FDS variant A3, in the third optimization step, a single twin traction drive (TM1, TM2) with an output of, for example, 230 kW can be used on the rear axle. Furthermore, if the RSP-4Q inverter according to Fig. 7b described here is used, the operating range of the regenerative braking can be further significantly extended according to the motor characteristic map in Fig. 7a.

[0319] This allows deceleration at the rear axle exclusively via the electric traction motors throughout the entire vehicle speed range up to the maximum speed. Furthermore, if the control functions described here are carried out via the electric traction motors TM1 and TM2, a base brake at the rear axle can be omitted entirely.

[0320] Complementary to this, hydraulic lines and control valves to the rear axle are also not required, so that the electrohydraulic brake unit EHB only needs to be designed for the front axle of the vehicle (see Figure 6c). Here too, a low-cost trapezoidal spindle can be used.

[0321] B: AD level 3~4 In the variant B1 of the driving dynamics system with a two-box system (e.g. X-Boost3 and ESP), an electro-hydraulic brake system as shown in FIG. 8 is used, which, when integrated into the driving dynamics system as described further, can meet the SAE Level 4 redundancy requirements and can also implement a downsized electro-hydraulic brake unit EHB at lower cost.

[0322] Furthermore, friction braking can already be reduced in terms of costs and weight in the basic braking function (a) by brake assistance via electric traction motors. The costs can be further reduced by the use of inexpensive disc brakes, especially on the front axle, and drum brakes on the rear axle.

[0323] In the case of variant B2 of the driving dynamics system with a central EHB-Z, if an electrohydraulic brake system according to Fig. 6a is used to assist the traction motors on two axles depending on the closed-loop control of the driving dynamics system described herein in the base brake and control functions, a functional redundancy level for ADL levels 3-4 can be achieved by a redundant configuration of the pressure supply devices, additionally by the above-mentioned redundancy functions as explained above with reference to Fig. 6a. It is assumed here that the hydraulic brake system is configured with four systems, which can still be operated with three systems in the event of a failure.

[0324] C: AD Level 5 For the variant C1 of the driving dynamics system with electromechanical brake units EMB, the third embodiment described above is based on a control ECU (S-ECU) which controls both the drive motor torque and the EMB for each wheel module. Rad1 , S-ECU Rad2 , S-ECU Rad3 , S-ECU Rad4 This is based on the fact that the driving dynamics system allows various cost and weight savings by simultaneously controlling the brake torque both in the basic braking function and in the control action.

[0325] In a first step, the EMB can be significantly downsized since a lower maximum torque is required.

[0326] Furthermore, compared to two-box solutions, the EMB described herein is significantly easier to apply and can be integrated into the central control of the driving dynamics system. A further advantage is the independence from the brake manufacturer.

[0327] If EMB is used for wheel modules according to the "architecture III" of the vehicle dynamics system, the electric power steering part EPS can be omitted as an option, since steering can be performed via the individual wheel motors with different motor speeds. In the case of the FDS variant C2 with an EHB axle module with piston-cylinder units, the EHB can also be significantly downsized, since a smaller maximum torque has to be achieved. Due to the common braking with the traction motor and the EHB, the friction brakes can likewise be constructed significantly lighter and cheaper. Two pressure regulators thus achieve a lower cost level and also provide the necessary redundancy for SAE level 5.

[0328] Further cost savings can be achieved through the use of drum brakes.

[0329] In contrast to the above-mentioned optimization method 2, if the variant C3 for the EHB of the rear axle is used with a simple pump (two-piston pump, gear pump), it is certainly not possible to achieve the same control quality with the pump as is generally achieved with a piston-cylinder unit, but this is less important at the rear axle. Furthermore, only a basic torque can be generated by the pump, while an additional braking torque that is controlled in a closed loop is generated by the traction motor at the rear axle.

[0330] Again, the use of drum brakes on the rear axle allows for further cost savings.

[0331] Variant C4 with central EHB-Z has already been considered for eligibility for AD levels 3-4 and further for eligibility for AD level 5. The operating unit can therefore be omitted.

[0332] The use of drum brakes on the rear axle allows for additional cost and weight savings compared to the electromechanical brake unit EMB.

[0333] In summary, it is observed that the variants C2 to C4 described in this specification reach the cost level of an SAE Level 2 solution, but meet all the redundancy requirements for SAE Level 5. Thus, the variants C2 to C4 can be evaluated as a solution for the most extended level of autonomous driving.

[0334] Compared to the EMB variant, this solution has the great advantage that components which are manufactured in large quantities, e.g. hydraulic pressure supplies or solenoid valves, are already provided and thus rapid series production can be introduced without high capital costs.

[0335] Additional explanation of another example : Another example includes an electric vehicle with central control by a driving dynamics system (FDS) or a driving dynamics system (FDS) having one of the following architectures: FDS Architecture I, II, or III. At least one wheel brake (RB1-RB4), Electric traction motors (TM1, TM2, TM3, TM4) used for both driving and braking at least one axle or wheel; at least one braking device (EMB, EHB) which is used to generate a braking torque in one or more wheel brakes, At least one electric traction motor (TM1 to TM4) and at least one brake device (EHB, EMB) are controlled by a control device (M-ECU) during the braking process. DOMAENE , S-ECU Achse , S-ECU Rad ) and sends target signals to the controllers of the traction motors (TM1 to TM4) and the brakes (EHB, EMB) for execution. DOMAENE ), A central computer performing at least one of the core functions ABS, ESP, EBV, ASR, ACC, AEB, electric traction motors on multiple axles and / or regenerative management with regenerative braking via at least one of the core functions (A) to (G) that are controlled in a closed or open loop manner. Equipped with - in service braking, if braking is performed by the electric traction motors (TM1 - TM4), also at high vehicle speeds (> 80 km / h), and the EBV function (EBV = electric braking force distribution to the front and rear axle) is simultaneously realized via the electric traction motors (TM1 - TM4) during braking, and / or During control operations (e.g. ABS, ESP), a braking torque is generated by at least one traction motor (TM1-TM4) and simultaneously at least one EHB or EMB, and a closed-loop control of the braking torque is performed at at least three wheels of the vehicle in the brake units (EMB, EHB) and / or the electric traction motors (TM1-TM4), thereby enabling a closed-loop control of the braking torque at the three wheels of the vehicle in each vehicle state.

Claims

1. 1. A driving dynamics system for a vehicle, comprising: at least one wheel brake (RB1, RB2, RB3, RB4) for dissipatively braking a wheel of the vehicle; at least one brake unit (EMB, EHB) assigned to said at least one wheel brake (RB1, RB2, RB3, RB4) and configured to generate a dissipative braking torque by means of said at least one wheel brake (RB1, RB2, RB3, RB4); at least one electric traction motor (TM1, TM2, TM3, TM4) driveably controllable to generate a regenerative braking torque for at least one wheel or axle of the vehicle; a central control unit (M-ECU) adapted for controlling the mutually combined activation of said at least one brake unit (EMB, EHB) and said at least one electric traction motor (TM1, TM2, TM3, TM4) for a braking function, such that a combined braking torque can be generated by means of said at least one brake unit (EMB, EHB) and said at least one electric traction motor (TM1, TM2, TM3, TM4); ＤＯＭＡＥＮＥ )and A driving dynamics system comprising: the braking function relates to a control case with open-loop and / or closed-loop control of a simultaneous basic braking torque and a closed-loop controlled additional braking torque, Optionally, said basic braking torque is provided by said at least one brake unit (EMB, EHB) and said closed-loop controlled additional braking torque is provided by said at least one electric traction motor (TM1, TM2, TM3, TM4), or the basic braking torque is provided by the at least one electric traction motor (TM1, TM2, TM3, TM4) and the closed-loop controlled additional braking torque is provided by the at least one brake unit (EMB, EHB), or said at least one brake unit (EMB, EHB) and said at least one electric traction motor (TM1, TM2, TM3, TM4) together respectively generate said basic braking torque and said closed-loop controlled additional braking torque, A driving dynamics system characterized by:

2. The braking functions include the following functions: Automated Emergency Brake (AEB) with total braking torque distribution to the rear and front axles and in particular EBV closed loop control, in particular EBV closed loop control on the rear and front axles of the vehicle; - an antilock braking system (ABS) with basic braking torque assistance, in particular via at least one traction motor (TM1, TM2, TM3, TM4); - Electric Stability Program (ESP); - Electronic Brake Force Distribution (EBV); - Anti-Slip Control (ASR); - Automated Cruise Control (ACC); - Recuperation management, in particular for individual recuperation per axle or per wheel; - Base brake with thermal management; - closed loop yaw moment control in case of failure of wheel brakes (RB1, RB2, RB3, RB4); and / or - Yaw moment intervention control for steering assistance, 2. The driving dynamics system of claim 1, wherein the driving dynamics system is selected from one of:

3. 3. The driving dynamics system according to claim 1, wherein the brake unit (EMB, EHB) comprises an electric drive (M) and is configured as an electrohydraulic brake unit (EHB) or as an electromechanical brake unit (EMB).

4. the brake unit (EHB) is configured as an electrohydraulic brake unit (EHB) having a pressure supply unit driven by an electric motor, a valve device is provided between the pressure supply unit and at least one wheel brake (RB1, RB2, RB3, RB4) or a plurality of wheel brakes (RB1, RB2, RB3, RB4) of one axle (HA, VA), The valve device is a wheel valve with pull-in resistance (MV ２ｋ，１ , M.V. ２ｋ，２ , M.V. ２ｋ，３ , M.V. ２ｋ，４ ) and / or circuit isolation valve (MV ２ｋ，ＴＶ ) In the event of leakage in at least one wheel brake (RB1, RB2, RB3, RB4), the valve device is configured to close and isolate the wheel brake (RB1, RB2, RB3, RB4) in question, and the central control unit (M-ECU ＤＯＭＡＥＮＥ ) is configured to drive and control the at least one brake unit (EMB, EHB) and / or the at least one electric traction motor (TM1, TM2, TM3, TM4) in such a way that a braking torque control is performed on further wheels, in particular at least three wheels, of the vehicle, in particular said valve arrangement makes it possible to separate the wheel brakes (RB1, RB2) of one axle (VA) of the vehicle, in particular the wheel brakes (RB1, RB2) of the front axle (VA); 4. A driving dynamics system according to claim 1.

5. The central control unit (M-ECU ＤＯＭＡＥＮＥ ) is at least one brake unit control device (S-ECU) of the brake unit (EMB, EHB) Ａｃｈｓｅ , S-ECU Ｒａｄ 5. The driving dynamics system according to claim 1, further comprising a vehicle steering system.

6. The central control unit (M-ECU ＤＯＭＡＥＮＥ ) in the braking function transmits a target signal to a motor control device (ECU-TM1, ECU-TM2, ECU-TM3, ECU-TM4) of the at least one traction motor (TM1, TM2, TM3, TM4) and a brake unit control device (S-ECU) of the at least one brake unit (EUB, EMB). Ａｃｈｓｅ , S-ECU Ｒａｄ ) 6. A driving dynamics system according to claim 1.

7. The central control unit (M-ECU ＤＯＭＡＥＮＥ ) is further configured to drive and control the at least one electric traction motor (TM1, TM2, TM3, TM4) for regenerative braking of the vehicle when the speed of the vehicle to be braked is above 80 km / h during normal driving, During the regenerative braking, an electric brake force distribution (EBV function) is realized simultaneously on the front and rear axles of the vehicle, in particular, between 20% and 40% of the total braking torque acts on the rear axle of the vehicle and between 60% and 80% of the total braking torque acts on the front axle of the vehicle; 7. A driving dynamics system according to claim 1.

8. wheel brakes (RB1, RB2, RB3, RB4) of wheels (R1, R2, R3, R4) of the vehicle are assigned unique brake units (EMB1, EMB2, EMB3, EMB4), in particular said brake units (EMB1, EMB2, EMB3, EMB4) are of electromechanical design, in particular, for each of the two wheels (R1, R2, R3, R4), a brake unit (EMB1, EMB2, EMB3, EMB4) assigned to the wheel brake (RB1, RB2, RB3, RB4) and an electric traction motor (TM1, TM2) are integrated into the wheel module, 8. A driving dynamics system according to claim 1.

9. a common brake unit (EHB1, EHB2) is assigned to the wheel brakes (RB1, RB2, RB3, RB4) of two wheels (R1, R2, R3, R4) of an axle (HA, VA) of the vehicle, in particular said brake units (EHB1, EHB2) are of electrohydraulic design, in particular a first brake unit (EHB1) is assigned to two wheels (R1, R2) of the rear axle (HA) and a second brake unit (EHB2) is assigned to two wheels (R3, R4) of the front axle (VA), 9. A driving dynamics system according to any one of claims 1 to 8.

10. a central brake unit (EHB-VA) is assigned to the wheel brakes (RB1, RB2, RB3, RB4) of the four wheels (R1, R2, R3, R4) of said vehicle, in particular the central brake unit (EHB-VA) is of electrohydraulic construction, 10. A driving dynamics system according to any one of claims 1 to 9.

11. one common brake unit (EHB-VA) is assigned to the wheel brakes (RB1, RB2) of the two wheels (R1, R2) of a first axle (VA) of the vehicle, in particular the front axle (VA), in particular, said brake unit (EHB-VA) is of electrohydraulic construction, - in particular for the wheel brakes (RB1, RB2) of the first axle (VA), a wheel-specific dissipative braking torque can be adjusted in the hydraulic lines between the brake unit (EHB-VA) and the wheel brakes (RB1, RB2), in particular by means of solenoid valves, in particular, said brake unit (EHB-VA) is further connectable via hydraulic lines to wheel brakes (RB1, RB2) of two wheels (R1, R2, R3, R4) of a second axle (HA), in particular the rear axle (HA); in particular, at the wheel brakes (RB3, RB4) of the second axle (HA), a common, dissipative braking torque, which is not individual for each wheel, can be adjusted; A driving dynamics system according to any one of claims 1 to 10.

12. a first electric traction motor (TM1) is assigned to a first pair of two wheels (R1, R2) of a first axle (HA), in particular a rear axle (HA) of the vehicle, and a second electric traction motor (TM3) is assigned to a second pair of wheels (R3, R4) of a second axle (VA), in particular a front axle (VA) of the vehicle; A driving dynamics system according to any one of claims 1 to 11.

13. - a first wheel (R1) and a second wheel (R2) of a first axle (HA), in particular a rear axle (HA) of the vehicle, are each assigned a specific electric traction motor (TM1, TM2); A driving dynamics system according to any one of claims 1 to 12.

14. the first wheel (R1) and the second wheel (R2) are furthermore each assigned their own brake unit (EMB1, EMB2), in particular the respective brake unit (EMB1, EMB2) being of electromechanical design, in particular the electric traction motors (TM1, TM2) respectively assigned to the first wheel (R1) and the second wheel (R2) and the brake units (EMB1, EMB2) respectively assigned to the first wheel (R1) or to the second wheel (R2) are integrated in a wheel module respectively assigned to the first wheel (R1) or to the second wheel (R2), 14. The driving dynamics system of claim 13.

15. Furthermore, a third electric traction motor (TM3) is commonly assigned to a third wheel (R3) and a fourth wheel (R4) of a second axle (VA), in particular a front axle (VA) of the vehicle, a common brake unit (EHB2) is assigned in particular to the third wheel (R3) and to the fourth wheel (R4), in particular the common brake unit (EHB2) being of electrohydraulic construction, in particular the third electric traction motor (TM3) and the common brake unit (EHB2) being integrated in an axle module assigned to the second axle (VA), or in particular, a central braking module (EHB-Z) is provided, in particular configured electrohydraulically, by means of which individual braking torques can be generated for the first wheel (R1) and for the second wheel (R2) and a common braking torque can be generated for the third wheel (R3) and for the fourth wheel (R4); A driving dynamics system according to claim 13 or 14.

16. - the central control unit (M-ECU ＤＯＭＡＥＮＥ ) is configured to distribute the basic braking torque and the closed-loop controlled additional braking torque between the at least one brake unit (EMB, EHB) and the at least one electric traction motor (TM1, TM2, TM3, TM4) depending on the vehicle deceleration and / or depending on the friction value of the road, - in particular when deceleration and / or friction values ​​are relatively low, e.g. in the case of ABS control on snow or ice or deceleration in an ACC braking operation, the electric motor brake unit (EMB) and / or at least one electric traction motor (TM1, TM2, TM3, TM4) generate said closed-loop controlled additional braking torque, - an electrohydraulic brake unit (EHB) generates said closed-loop controlled additional braking torque, in particular when deceleration and / or friction values ​​are relatively high, for example when braking on asphalt, - in particular in the case of moderate deceleration and / or friction values, the brake unit (EHB, EMB) or the traction motor (TM1, TM2, TM3, TM4) forms the basic braking torque as a constant braking torque and a further brake unit (EMB, EHB) or the traction motor (TM1, TM2, TM3, TM4) forms the closed-loop controlled additional braking torque, 16. A driving dynamics system according to any one of claims 1 to 15.

17. The central control unit (M-ECU ＤＯＭＡＥＮＥ ) is configured to perform EBV control during automatic emergency braking (AEB), a braking torque gradient of the at least one brake unit (EMB, EHB) and the at least one electric traction motor (TM1, TM2, TM3, TM4) is taken into account such that a maximum braking torque is simultaneously achieved on the front axle (VA) and on the rear axle (HA) of the vehicle; 17. A driving dynamics system according to any one of claims 1 to 16.

18. During regenerative braking, especially when the vehicle battery is fully charged, the following strategy is used: - feeding back the regenerated energy to the battery up to the limit of power consumption; - Field oriented control (Id / Iq current control) of the electric traction motor so that energy is dissipated inside the motor; - dissipating the energy gained by the generator operation of the electric traction motors (TM1, TM2, TM3, TM4) and supplying the energy gained for the electric consumers of the vehicle and / or heating a fluid reservoir for use in a heat pump for cooling or heating; and / or - using intermediate electrical storage devices designed for pulsed output, such as supercapacitors; At least one of the following is used:

18. A driving dynamics system according to any one of claims 1 to 17.

19. at least one electric traction motor (TM1, TM2, TM3, TM4) with an inverter for switching the windings of said at least one electric traction motor (TM1, TM2, TM3, TM4) in a series or parallel circuit is driven by three strands each of an excitation coil of a brushless electric motor, a four-quadrant operation is possible, in particular with the inverter, i.e. with quadrant 1 having a positive rotation speed and positive torque of the electric motor, quadrant 2 having a positive rotation speed and negative torque of the electric motor, quadrant 3 having a negative rotation speed and positive torque of the electric motor and quadrant 4 having a negative rotation speed and negative torque of the electric motor; 19. A driving dynamics system according to any one of claims 1 to 18.

20. The central control unit (M-ECU ＤＯＭＡＥＮＥ ) is configured to execute said brake control based on a characteristic map, in particular, the characteristic map represents a pressure-volume characteristic curve, the relationship between the motor current and the brake pressure and / or the relationship between the brake pressure and / or the deceleration when the wheel brake is heated, 20. A driving dynamics system according to any one of claims 1 to 19.

21. The central control unit (M-ECU ＤＯＭＡＥＮＥ ) is configured to detect sensor data during operation of the vehicle, in particular in a state after the start of operation of the vehicle, for example during a driving operation or in a stationary state before or after a driving operation, and to adapt the control of the braking function based on the detected sensor data using an artificial intelligence process, in particular machine learning or a neural network, In particular, the artificial intelligence process is implemented in the central control unit (M-ECU ＤＯＭＡＥＮＥ ) executable by a computer, In particular, the adaptation is performed in a safe state of the vehicle, in particular in a parked state of the vehicle, where - in particular on the basis of the detected sensor data, for example pressure-volume characteristic curves, characteristic maps which represent the relationship between motor current and brake pressure and / or the relationship between brake pressure and / or deceleration when the wheel brake is heated are determined, In particular, the characteristic map can be adapted based on the sensor data and the artificial intelligence process if deviations from the current characteristic map are identified, for example due to environmental influences, the air in the system or heating of the wheel brakes; 21. A driving dynamics system according to any one of claims 1 to 20.

22. 1. A driving dynamics system for a vehicle, comprising: at least one electric traction motor (TM1, TM2, TM3, TM4) that can be driven and controlled to generate a regenerative braking torque for at least one wheel or axle of the vehicle; a central control unit (M-ECU) adapted to drive and control said at least one electric traction motor (TM1, TM2, TM3, TM4) for braking functions; ＤＯＭＡＥＮＥ )and In a driving dynamics system comprising: - the central control unit (M-ECU ＤＯＭＡＥＮＥ ) during braking on roads with low friction values, in particular on snow, ice and / or wet roads, at low to moderate decelerations, in particular below 0.5 m / s ２ configured to perform a braking function at a deceleration rate of less than In particular, the central control unit (M-ECU ＤＯＭＡＥＮＥ ) is configured to perform the braking function by at least one traction motor of at least one axle of the vehicle, in particular by two traction motors of the rear axle of the vehicle, A driving dynamics system characterized by:

23. A vehicle equipped with a driving dynamics system according to any one of claims 1 to 22.

24. 1. A method of operating a driving dynamics system, comprising: The driving dynamics system comprises at least one brake unit (EMB, EHB) for generating a dissipative braking torque, at least one electric traction motor (TM1, TM2, TM3, TM4) for generating a regenerative braking torque for at least one wheel or axle of the vehicle, and a central control unit (M-ECU) for controlling the at least one brake unit (EMB, EHB) and the at least one electric traction motor (TM1, TM2, TM3, TM4) for the braking function. ＤＯＭＡＥＮＥ ) , a combined braking torque is generated by means of said at least one brake unit (EMB, EHB) and said at least one electric traction motor (TM1, TM2, TM3, TM4), the braking function relates to a control case with open-loop and / or closed-loop control of a simultaneous basic braking torque and a closed-loop controlled additional braking torque, Optionally, said at least one brake unit (EMB, EHB) is controlled to generate a basic braking torque and said at least one electric traction motor (TM1, TM2, TM3, TM4) is controlled to generate said closed-loop controlled additional braking torque, or said at least one electric traction motor (TM1, TM2, TM3, TM4) is controlled to generate said basic braking torque and said at least one brake unit (EMB, EHB) is controlled to generate said closed-loop controlled additional braking torque, or said at least one brake unit (EMB, EHB) and said at least one electric traction motor (TM1, TM2, TM3, TM4) are respectively driven and controlled to generate together said basic braking torque and said closed-loop controlled additional braking torque, A method comprising:

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