Drive train for vehicle having wheels and method for adjusting brake pressure

Abstract

The invention relates to a driving power system for a vehicle having wheels (R1-R4), comprising: a main control unit (M-ECU) for detecting and / or generating steering and braking commands; at least two hydraulically actuatable wheel brakes (RB1-RB4), each wheel brake being associated with a respective one of the wheels (R1-R4); at least one electric traction motor having a traction motor control unit, the traction motors (TM1, TM2) for driving at least one of the wheels (R1-R4), the main control unit being communicatively connected to the traction motor control unit for controlling the traction motors (TM1, TM2) to execute steering and braking commands; the invention relates to a driving power system, in particular a main control unit (M-ECU), comprising at least one (first) electro-hydraulic pressure supply unit (BM1), in which a brake pressure control valve in the form of a dedicated solenoid valve (MV2k), which valve can be closed in particular, and one of the outlet valves (AV1-AV4) are associated with at least one hydraulically actuatable wheel brake (RB1-RB4), in which the driving power system, in particular the main control unit (M-ECU), is connected to at least one (first) electro-hydraulic pressure supply unit (BM1). And a dedicated solenoid valve (MV2k) configured to selectively release pressure in the at least one hydraulically actuatable wheel brake by means of the associated outlet valve or by means of the dedicated solenoid valve (MV2k).

Description

Technical Field

[0001] The invention relates to a driving dynamics system (FDS) having a master control unit or central computer (M-ECU) and a method for regulating brake pressure according to the preamble of claim 1 . Background Art

[0002] Brake pressure control systems for electrohydraulic brakes (EHB) based on the return principle with pre-pressure provided by the master brake cylinder have been developed since the introduction of anti-lock braking systems (ABS), traction control systems (TCS) and electronic stability programs (ESP) on the market in 1978, 1986 and 1995. Here, the pressure increase is achieved by throttling the inlet valve with PWM and the pressure reduction is achieved by time control of the outlet valve. The valve block, electric motor, pump, accumulator chamber, eight solenoid valves (for ABS) or twelve solenoid valves (for ESP), pressure sensor and electronic control unit (ECU) are usually integrated into a single unit and installed separately from the brake booster (BB) in the engine compartment.

[0003] In vehicles currently on the market, the most common use is of an ABS / ESP pump unit in combination with a vacuum brake booster and a vacuum pump. So-called "two-tank" brake systems with an electrohydraulic brake booster and a spatially separated ESP unit (see German patent application DE102012211278A1) and so-called "single-tank" brake systems with an integrated brake booster and pressure regulation (see European patent EP1907253B1, German patent application DE102013222281A1) are standard for new vehicles.

[0004] Since its series introduction in 1995, the hydraulic design of the ESP unit with twelve solenoid valves as pressure supply unit has not changed, but a standardized interface has been specified for the interaction between the control unit of the electric brake booster and the control unit of the ESP unit (see VDA 360 for details) in order to implement additional functions and component protection for rigid electromechanical brake boosters. For example, the solenoid valves of the ESP unit are activated for specific functions by the control device. German patent application DE102012211278A1 describes the control of valves and ABS pumps for regenerative braking.

[0005] The automotive industry is undergoing a major transformation. In addition to the increasing penetration of electric vehicles in the market, it is currently experiencing different stages of autonomous driving (Levels 2 to 5 as defined by the Society of Automotive Engineers, or SAE Levels 2-5), with each stage of autonomous driving increasing the redundancy requirements for the braking systems used (see the article "Brake Booster for Autonomous Driving" in Automotive Technology Magazine, Issue 3, 2019).

[0006] In addition, a vehicle central control system with a control unit for chassis control (hereinafter referred to as "vehicle motion control" (VMC) or "vehicle chassis control" (VCC)) is introduced, which includes electro-hydraulic brakes, electric traction motors on one or more axles of the vehicle, TM , electric power steering (EPS) and optionally also damping. Due to the central control system, synergies can be exploited.

[0007] Since 2020, for the first time, regenerative braking in the "Formula E" racing series with the help of powerful electric traction motors does not follow the "hybrid strategy" defined as standard in the 5th edition of the "Brake Manual" (see Chapter 19: "Regenerative braking systems"), in which the hydraulic braking torque is reduced by the braking torque of the electric traction motor. Instead, the braking torque is additionally generated by the electric traction motor and the electrohydraulic brake in order to reduce the time required to reach the blocking braking torque / blocking braking pressure (TTL). This shortens the braking distance by building up the braking torque as quickly as possible. Current limitations and problems with prior art ABS / ESP systems

[0008] One problem with current ABS / ESP brake systems with pump units is the limited power of new functions such as automatic emergency brake (AEB). For this function, it is very important to increase the brake pressure to the wheel locking pressure (typical values ​​in passenger car brake systems: 80-100 bar) in the shortest possible time. While ABS / ESP brake systems with pumps and electric brushed motors can reach a pressure of 50 bar in 450 milliseconds, single-box brake systems with powerful brushless motors (German patent DE102005063659B3) can reach a wheel locking pressure of 80-100 bar in less than 150 milliseconds. A short TTL time can mean that the braking distance can be reduced by more than 5 meters at an initial speed of 65 kilometers per hour (km / h).

[0009] In principle, every ABS / ESP brake system (ABS / ESP brake system with pump unit and single tank) has non-return valves which are connected hydraulically in parallel with the inlet valves in the hydraulic line to the wheel brakes for safety reasons and ensure that the pressure in the wheel brakes is always reduced automatically, i.e. no pressure remains in the wheel brakes if the pressure supply fails. However, this technical solution means that wheel brake circuit faults are difficult or impossible to diagnose, since it is not clear whether it is the non-return valve or the inlet valve that causes the wheel circuit fault. Therefore, in the event of a fault, the entire brake circuit with both wheel brakes must be deactivated. This is why the diagonal brake circuit layout (X brake circuit) is the preferred layout in most vehicles, since in the event of a brake circuit fault, braking can still be performed using the front wheel brakes, which have a better braking effect than the rear wheel brakes. The so-called "black / white" brake circuit distribution (II brake circuit) is used in hybrid vehicles or electric vehicles, which has the disadvantage of poor braking effect in the event of a fault, but the advantage is that the control strategy for regenerative braking is simpler to implement.

[0010] Furthermore, compared to the above-mentioned single-tank brake system (see German patent application DE102013222281A1) which reduces the pressure by releasing the pressure into the reservoir, the ABS / ESP brake system with a pump unit and which reduces the pressure by releasing the pressure into the accumulator chamber via a time-controlled outlet valve has disadvantages in terms of braking distance control performance, because the back pressure in the accumulator chamber (up to 5 bar) during the pressure reduction limits the rapid pressure reduction under low pressure conditions. In the case of ABS control on roads with low friction coefficients and low-μ (ice and snow), this leads to a slow pressure reduction, so that the time for the wheel speed to drop during ABS control needs to be very long. This leads to long braking distances. In some cases, ABS can only perform basic control on roads with very low friction coefficients (icy roads). As a result, due to the poor control performance, even in normal operation, standard ABS / ESP systems have a clear disadvantage in terms of braking distance compared to the new standards set by single-tank brake systems. Summary of the invention

[0011] The object of the invention is to provide an improved driving dynamics system, in particular in the form of a plurality of pressure supply units (a two-box solution, i.e. two hydraulic supply units connected in series in two separate hydraulic supply units, each with a separate pressure actuator for two wheel brakes). Preferably, the system should solve the above-mentioned problems. The system should be small, reliable, precise, safe and efficient.

[0012] The driving dynamics system should also meet the requirements for automated driving operation (SAE Level 3, Level 4 automated driving with driver request detected by an electronic pedal, or SAE Level 5 automated driving without a pedal with setpoints specified by a central computer) and require the creation of new interfaces between the brake module or pressure supply unit and / or the brake module and the central computer.

[0013] In addition, the system should be able to effectively provide driving dynamics control functions (ABS, ESP, EBD, ACC, AEB, Recu-Mgt (Recuperation Management)) and wheel-specific braking torque intervention (Brake-to-Steer (BtS), Brake-to-Torque Vectoring (BtTV)) while integrating at least one electric traction motor.

[0014] This object is achieved by the subject matter according to claim 1 .

[0015] Specifically, the object is achieved by a driving power system for a vehicle having wheels, the system comprising: a main control unit for detecting and / or generating steering commands and braking commands; at least two hydraulically actuatable wheel brakes, each wheel brake being associated with a respective wheel; at least one electric traction motor having a traction motor control unit, wherein the traction motor is used to drive at least one of the wheels, and the main control unit is communicatively connected with the traction motor control unit to control the traction motor to execute steering commands and braking commands; At least one (first) electro-hydraulic pressure supply unit, comprising: at least one electric pump unit; at least two connecting lines for connecting the wheel brakes; an electrically actuatable wheel brake pressure regulating valve or brake pressure regulating valve; and a first auxiliary control unit; In this case, at least one of the hydraulically actuatable wheel brakes (RB1-RB4) is associated with a brake pressure regulating valve and an outlet valve, the brake pressure regulating valve being in the form of a special solenoid valve (MV2k), which can in particular have anti-passive closing properties, Therein, the driving dynamics system, in particular the main control unit (M-ECU), is configured to selectively release the pressure of at least one hydraulically actuatable wheel brake via an associated outlet valve or via a dedicated solenoid valve (MV2k).

[0016] In the first variant, preferably, the pressure is reduced only through the corresponding outlet valve. In the second variant, the pressure can be reduced via the corresponding dedicated solenoid valve alone or via the dedicated solenoid valve and the outlet valve at the same time.

[0017] Furthermore, the object is achieved by a driving power system, comprising: a main control unit for detecting and / or generating steering commands and braking commands; at least two hydraulically actuatable wheel brakes, each wheel brake being associated with a respective wheel; at least one electric traction motor having a traction motor control unit, wherein the traction motor is configured to drive at least one of the wheels, wherein the main control unit is communicatively connected to the traction motor control unit to control the traction motor to execute a steering command and a braking command; At least one (first) electro-hydraulic pressure supply unit, comprising: At least one electric pump unit: at least two connecting lines for connecting the wheel brakes; an electrically actuatable wheel brake pressure regulating valve or brake pressure regulating valve; and a first auxiliary control unit; Among them, at least one of the brake pressure regulating valves includes a dedicated solenoid valve, which has an electromagnetic drive device with a first excitation coil, via which the valve actuator or the valve tappet can be adjusted between a valve opening position and a valve closing position.

[0018] One aspect of the present invention is that the dedicated solenoid valve has an additional force device, which includes a permanent magnet and / or a second excitation coil, and the additional force device is used to provide at least one holding force acting on the valve actuator or the valve tappet. Preferably, the dedicated solenoid valve that can be used as an inlet valve or a wheel inlet control valve has an anti-passive closing feature in this embodiment.

[0019] Due to the design of the wheel brake circuits with wheel inlet control valves that prevent passive closing, the system of the invention has significantly higher fail-safety than the brake systems of the prior art and a brake system with wheel circuits (pressure control and / or supply for the wheels) can be used instead of conventional brake circuits with multiple wheels (diagonal or black and white braking). For example, a fault in a wheel circuit can be diagnosed and the faulty wheel circuit can be disconnected from the pressure supply by closing the inlet valve. This means that if one (individual) wheel circuit fails, in the event of a fault, a significantly improved deceleration can be achieved with the remaining three wheel circuits and yaw torque intervention can still be performed on the three wheels. In the following, a brake module with a first pressure supply unit with a dedicated solenoid valve according to claim 1 is referred to as ESP-X.

[0020] For example, the main control unit can detect steering commands and / or braking commands via steering wheel sensors or force / displacement sensors on the electric brake pedal. However, the main control unit can also be used to generate independent steering commands and braking commands. This is necessary during autonomous driving. Due to the implementation of safety functions, such as automatic emergency braking (AEB), corresponding commands can also be generated. The steering command of the present invention is not limited to a specific intervention of the driver with the aid of the steering wheel. On the contrary, the present invention understands a steering command as any instruction related to the movement of the vehicle in a specific direction, and also includes trajectory control in autonomous driving mode. For example, this also includes commands that cause a change in the yaw moment. Torque vectoring can also be implemented using corresponding steering commands and / or braking commands.

[0021] The (first) electrohydraulic pressure supply device may be an ABS / ESP unit. However, this should generally be understood to mean any unit having a pressure generator, for example in the form of a pump unit as described above, which provides a corresponding pressure at a corresponding connection point. The pressure supply unit may also perform a regulating and / or control function. Thus, it may also be a pressure control module.

[0022] One aspect of the present invention is that the dedicated solenoid valve provides additional holding force. Thus, the dedicated solenoid valve has the property of preventing passive closing and high pressure can be released through the valve. In addition to the holding force, the dedicated solenoid valve can also provide a restoring force to move the valve actuator or valve tappet to the valve open position.

[0023] In one embodiment, the main control unit can be used to control the dedicated solenoid valve of the first pressure supply unit, at least in the selected braking mode, so that when the dedicated solenoid valve is opened, the pressure in the wheel brake assigned to the dedicated solenoid valve is released. Preferably, each dedicated solenoid valve of the first pressure supply unit is assigned to a wheel brake. Due to its design to prevent passive closure, the corresponding dedicated solenoid valve can be used not only as an inlet valve, but also as an outlet valve. The pressure can be increased and released in both directions by the same dedicated solenoid valve. This enables the assigned wheel brake to be (significantly) depressurized quickly, because the pressure can be released via several valves (dedicated valves) and via the outlet valve. In addition, when the pressure in the wheel brake is high and the pressure generator is operating in a low-pressure state, the pressure in the wheel brake can be maintained by closing the valve. This provides new degrees of freedom, which is very advantageous in a central control strategy using a main control unit.

[0024] In one embodiment, at least one of the wheel brakes associated with the dedicated solenoid valve also has an outlet valve. A corresponding outlet valve can be assigned to the wheel brake. In one embodiment, the outlet valve and the dedicated solenoid valve are used simultaneously to reduce the pressure in order to reduce the pressure in the corresponding wheel brake as quickly and effectively as possible. In particular, the main control unit can be configured to control the associated dedicated solenoid valve and the outlet valve at least in the selected braking mode so that the brake fluid in the wheel brake is discharged simultaneously via the associated dedicated solenoid valve and the associated outlet valve.

[0025] In one embodiment, the driving dynamics system has at least one second pressure supply unit. Preferably, the unit includes a piston-cylinder unit or a rotary pump, i.e., a separate pressure generator. The second pressure supply unit can be connected to at least one input end of the first pressure supply unit to provide brake fluid. In one embodiment, the pressure supply unit not only functions as a pressure accumulator, but also functions as a (controllable / adjustable) pressure trap (pressure reduction device) or alternatively has at least one valve for reducing pressure (e.g., a central outlet valve, see WO2020165259A1, outlet valve of ABS / ESP unit). The pressure reduction (pressure reduction) can be time-controlled by the valve, but PWM control can also be performed if the inlet valve of the ABS / ESP unit is used for pressure reduction. For example, if a piston-cylinder unit is used, a very low pressure, such as 1 to 5 bar (bar) pressure, can be generated by retracting the cylinder into the piston, where the existing pressure difference causes the pressure in the wheel brake to drop rapidly. In a (preferred) embodiment, the pressure supply unit provides brake fluid for the first and second brake circuits, wherein preferably, at least one isolation valve is provided for isolating the first and / or second brake circuits. As explained in more detail below, the isolating valve can be designed similarly or identically to the special solenoid valve already described.

[0026] It is also possible to provide a plurality of first pressure supply units and connect them to the second pressure supply unit.

[0027] In one embodiment, the first pressure supply unit is (directly) connected to exactly two wheel brakes. Preferably, these two wheel brakes are associated with wheels located on a first axle. In one embodiment, in addition to the first pressure supply unit, at least one further pressure supply unit is provided, which is (directly) connected to at least two wheel brakes on a second axle. In other words, the further pressure supply unit supplies two wheel brakes associated with wheels located on the second axle. According to the invention, a plurality of first pressure supply units can therefore be arranged as different modules, each of which is associated with a specific axle or wheel brakes on a specific axle. Depending on the vehicle, in addition to the first axle and the second axle, further axles with further pressure supply units can also be provided, wherein each pressure supply unit of the axle is preferably communicatively connected to a main control unit for receiving steering commands and braking commands. According to the invention, a direct connection of one device to another device can be understood as providing a hydraulic connection, for example via a pipeline, which is not interrupted by other devices, such as valves or pressure generators.

[0028] In one embodiment (hereinafter also referred to as valve connection variant I), the dedicated solenoid valve is connected to the wheel brake via the armature chamber of the valve, while its valve seat is connected to the pressure supply unit, which is a common situation in the ABS / ESP system of the prior art, and the solenoid valve is designed to be in the open state when the power is off. The pressure can be built up (increased) by pre-pressure control and PWM control of one or more dedicated solenoid valves. The pressure release (pressure reduction) is achieved by time control of the same valve. Due to the design of anti-passive closing, there is no risk of the dedicated solenoid valve being passively closed during the pressure reduction process.

[0029] In one (other) embodiment (valve connection variant II), the valve seat of at least one dedicated solenoid valve is connected to the wheel brake. This arrangement allows the pressure in the corresponding wheel brake to be released smoothly. Thanks to this arrangement, the valve opening cross section can be adjusted, in particular by PWM control or current control. This makes it possible to throttle and reduce the pressure by means of a dedicated solenoid valve. In this embodiment, the pressure increase by the dedicated solenoid valve can be achieved by time control or volume measurement, which can be carried out in the second pressure supply unit, for example by adjusting the rotation angle of the rotary pump or the piston stroke of the piston-cylinder unit.

[0030] Both types of connection can be closed simply by energizing the dedicated solenoid valve, thereby disconnecting the wheel brake from the system. It is also possible to apply a lower holding current to keep the dedicated solenoid valve closed. Disconnection can be advantageous if a defect such as a leak has been detected in the corresponding wheel brake.

[0031] In one embodiment, the first supply unit may include a rotary pump connected to the wheel brakes and configured to increase and release the pressure in the wheel brakes. Thus, the rotary pump may act as a pressure sink and achieve rapid pressure reduction.

[0032] Furthermore, the object is achieved by a driving power system, which comprises: a main control unit for detecting and / or generating steering commands and braking commands; four hydraulically actuatable wheel brakes, each wheel brake being associated with a wheel; at least one electric traction motor having a traction motor control unit, wherein the traction motor is configured to drive at least one of the wheels of the vehicle, wherein the main control unit is communicatively coupled to the traction motor control unit to control the traction motor to execute steering commands and braking commands; At least one first electro-hydraulic pressure supply unit, comprising: at least one electric pump unit; at least two connecting lines for connecting the wheel brakes; an electrically actuatable wheel brake pressure regulating valve or brake pressure regulating valve; and a first auxiliary control unit; at least one second electro-hydraulic pressure supply unit configured to provide brake fluid to the first brake circuit and the second brake circuit at at least one inlet of the first pressure supply unit; wherein at least one isolating valve in the form of a dedicated solenoid valve is assigned to the second pressure supply unit, which isolating valve is used to isolate the first and / or second brake circuit; The dedicated solenoid valve comprises an electromagnetic drive device having a first excitation coil, via which a valve actuator or a valve tappet of the dedicated solenoid valve can be adjusted between a valve opening position and a valve closing position.

[0033] Alternatively, the object is achieved by a system for a vehicle having wheels (R1-R4), in particular a driving dynamics system, in particular as described in the previous embodiments. The system may include: a main control unit (M-ECU) for detecting and / or generating steering commands and braking commands; four hydraulically actuatable wheel brakes (RB1-RB4), wherein each wheel brake is respectively associated with one of the wheels (R1-R4); at least one electric traction motor (TM1, TM2) having a traction motor control unit (S-ECU-TMHA), wherein the traction motor (TM1, TM2) is used to drive at least one of the wheels (R1-R4) of the vehicle, wherein a main control unit (M-ECU) is communicatively connected with the traction motor control unit to control the traction motor (TM1, TM2) to execute steering commands and braking commands; At least one first electro-hydraulic pressure supply unit (BM1), comprising: at least one electric pump unit; at least two connecting lines for connecting wheel brakes (RB1-RB4); an electrically actuatable wheel brake pressure regulating valve or brake pressure regulating valve; and A first auxiliary control unit (S-ECU1); at least one second electro-hydraulic pressure supply unit (BM2) configured to supply brake fluid to the first brake circuit (BK1) and the second brake circuit (BK2) at at least one inlet of the first pressure supply unit; wherein at least one isolating valve (TV1, TV2) in the form of a dedicated solenoid valve (MV2k) is used to isolate the first and / or second brake circuit (BM1, BM2); The dedicated solenoid valve (MV2k) comprises an electromagnetic drive device having a first excitation coil (SP1a), via which the valve actuator (7) or valve tappet (7a) of the dedicated solenoid valve (MV2k) can be adjusted between a valve opening position and a valve closing position.

[0034] The system is characterized in that the dedicated solenoid valve (MV2k) is protected against passive closing, in particular by providing an additional force device, which includes a permanent magnet (PM) and / or a second excitation coil (SP1b, SP2), and the additional force device is configured to provide at least one holding force (FPM, FEM2) acting on the valve actuator (7) or the valve tappet (7a).

[0035] One aspect of the present invention is that the dedicated solenoid valve has a function of preventing passive closing, especially by providing an additional force device, which includes a permanent magnet and / or a second excitation coil, and the additional force device is configured to provide at least one retaining force acting on the valve actuator or the valve tappet.

[0036] Thus, the dedicated solenoid valve can also be used as an isolating valve, for example as part of a second pressure supply unit (hereinafter also referred to as second brake module BM2), wherein the second brake module BM2 does not have to comprise an isolating valve if there is only one hydraulic connection to the first brake module. Fig. 9 , Fig.10 , Fig.15 ), and in embodiments without an isolation valve, also referred to as brake module BM2. The property of anti-passive closing also leads to a significant improvement of the system. Generally, according to the invention, other valves with corresponding anti-passive closing properties can also be used. The system is preferably a two-tank system, in which the first pressure supply unit is part of the first tank and the second pressure supply unit is part of the second tank.

[0037] If a dedicated solenoid valve having the above-mentioned permanent magnet and / or second excitation coil is used, it can be designed similarly or identically to the above. The additional force device can also generate an additional restoring force in addition to the aforementioned holding force.

[0038] By advantageously using a second pressure supply unit for reducing the pressure to a low friction coefficient, even low-cost ABS / ESP brake systems can reach a new level in terms of control quality and compete with modern single-box brake systems in terms of braking distance performance (German patent application DE102013222281A1, Braking Manual 5th edition, Chapter 20.3 "Integrated brake system MK C1").

[0039] Regardless of how the second pressure supply unit is designed, in one embodiment, the first pressure supply unit can be equipped with a rotary pump that can achieve pressure increase and pressure reduction depending on the rotation direction of the rotary pump, which creates a further degree of freedom for pressure reduction. In addition, in this embodiment, since there is no back pressure in the accumulator chamber, the pressure can be easily reduced when the ABS is operating under low friction coefficient ("low-μ") conditions. This creates a highly accurate and cost-effective system.

[0040] In a (further) embodiment, the first pressure supply unit can be designed to provide a pressure reduction into the reservoir instead of into the accumulator chamber. This is possible because the dedicated solenoid valve according to the invention, especially when used as an inlet valve, brings a high safety gain and significantly improves the ABS control performance.

[0041] In one embodiment, a braking torque is simultaneously built up on one or more axles together with the electric traction motor by means of the pressure of the electric traction motor and the first and / or second pressure supply unit. In this case, an electrical brake force distribution (EBD) can be performed during the pressure build-up by means of the first and / or second pressure supply unit in order to prevent the rear wheels from locking before the front wheels. If the wheel locking pressure is reached, ABS control can be initiated according to the invention and the braking torque of at least one traction motor can be rapidly reduced. For electric traction motors operating at high voltages (greater than 400 volts (V), in particular greater than 700 V) and with a braking torque gradient greater than 10,000 Newton meters per second (Nm / s), the corresponding operating sequence does not pose a safety risk and the operating speed is fast enough to achieve a safe braking torque reduction, if necessary within the first control cycle. According to the invention, this can be achieved by introducing a central vehicle dynamics control FDS, which synchronizes the electric traction motor TM and the pressure generator unit and can quickly detect ABS situations by evaluating the wheel speed sensors. For this purpose, the main control unit can be communicatively connected to the wheel speed sensors so that the corresponding sensor values ​​can be read directly. Thanks to the method according to the invention, in the case of automatic emergency braking, where the pressure is generated only by the pump of the first brake module BM1, a TTL of 150 ms can be achieved, whereas previously only single-box brake systems with powerful brushless motors could achieve comparable values.

[0042] Alternatively or additionally, in addition to the electric traction motor, a 6-piston pump or a more powerful brushed motor can also be used in the first pressure supply unit of the invention, which allows even shorter TTL times to be achieved. In this way, good TTL times, possibly in the range of 150 ms, can also be achieved with less powerful electric traction motors. According to the invention, the various technical solutions can be combined differently in a modular concept.

[0043] The pressure supply unit can be configured to increase and decrease pressure. Each pressure supply unit of the first and second pressure supply units has an auxiliary control unit, and each auxiliary control unit has at least one communication interface. These communication interfaces can be used to establish communication with the main control unit. In particular, measurement signals and control set points can be exchanged. The dedicated solenoid valve of the second pressure supply unit can be arranged so that the valve seat of the dedicated solenoid valve is (directly) connected to the input end of the first pressure supply unit (valve connection variant III). Due to the arrangement of the dedicated solenoid valve, the valve opening cross section can be adjusted, in particular by means of PWM control or current control. In this case, this special arrangement also means that the pressure of the first pressure supply unit can be throttled by a dedicated solenoid valve, thereby achieving low-noise pressure reduction. In this arrangement, the pressure is preferably increased by time control or volume measurement (see the previous explanation of pressure control / pressure regulation by volume measurement).

[0044] In one embodiment, the main control unit is configured to implement a pressure control for the wheel brakes or for the brake circuit by activating at least one of the dedicated solenoid valves of the first pressure supply unit and / or of the at least one second pressure supply unit.

[0045] In one embodiment, the main control unit is configured to detect wheel circuit faults by measuring the pressure when a dedicated solenoid valve or inlet valve of the first pressure supply unit is closed. A corresponding diagnostic procedure can include measuring whether the pressure in the system drops if all relevant valves are closed. If this is the case, it can be assumed that there is a leak. By closing the dedicated solenoid valve, pressure can still be built up in the remaining brake circuit or other wheel circuits without leaks. For example, the second pressure supply unit can increase the pressure by a piston movement.

[0046] If there is no pressure increase associated with the piston movement, a leak can also be concluded in this case.

[0047] As already explained, the main control unit can be configured to isolate the faulty brake circuit by closing at least one of the isolation valves. Thus, in some embodiments, a circuit break for a wheel circuit or for a brake circuit can be isolated in order to isolate the faulty brake circuit or wheel brake circuit while maintaining the functionality of the rest of the system.

[0048] The main control unit can be configured for implementing (axle-dependent) ABS by controlling at least one of the isolation valves and (alternatingly) performing a pressure build-up and a pressure reduction via the second pressure supply unit. Unlike conventional systems, the second pressure supply unit can therefore also be used to implement at least a (basic) single-channel ABS. This results in additional redundancy.

[0049] In one embodiment, the main control unit is configured to implement (automatic) emergency braking by actuating the traction motor and at least the first pressure supply unit in parallel. It is also possible to implement the corresponding control strategy with only one traction motor.

[0050] The main control unit can be configured to realize an (automatic) emergency braking function (AEB) or a braking torque build-up by controlling the electric traction motor and the electro-hydraulic brake, in particular to realize a higher braking torque (vehicle deceleration> 3 m / s 2 (m / s 2 )). When emergency braking is applied, the braking torques of the electric traction motor and the first pressure supply unit are superimposed until a higher deceleration (>5m / s) is achieved. 2 ), preferably until the maximum deceleration (> 8m / s 2 , especially >9.5m / s 2 ). During the emergency braking function, i.e. during a highly dynamic pressure build-up, an ABS situation can be detected by evaluating the wheel speed sensors. In this case, the main control unit can reduce the braking torque of the electric traction motor and / or the electrohydraulic brake (central) on one or more locked wheels or the braking torque of the axle.

[0051] In one embodiment, the first electromagnetic drive device adopts a redundant design and is equipped with at least one first electromagnetic valve driver and one second electromagnetic valve driver, wherein the auxiliary control unit for controlling the at least one dedicated electromagnetic valve is communicatively connected to the first electromagnetic valve driver, and the main control unit for controlling the at least one dedicated electromagnetic valve is communicatively connected to the second electromagnetic valve driver. This means that the dedicated electromagnetic valve can be actuated by two independent control units, so that even if one of the control units fails, the actuation of the dedicated electromagnetic valve can continue to be ensured. The communication connection can be an electrical connection.

[0052] In one embodiment, the main control unit is configured to at least auxiliary set the brake pressure for at least one selected wheel brake by a multiplexing / PPC process, wherein the main control unit sends a control signal to the second pressure supply unit to build up or reduce the pressure.

[0053] In one embodiment, a new FDS architecture is created with a communication interface Int between the central computer or master control unit and the control unit of the brake module (BM1 or BM2). BM1 、Int BM2 , and in the case of multiple brake modules (BM1 and BM2), there is also another interface Int between the control units S-ECU1 and S-ECU2 of the two brake modules. 2BM . Int 2BMThe interface is based on the VDA360 guideline, which defines the interaction between an electric regenerative brake booster (e.g. the i-booster product) and an ESP-hev brake system for energy recovery braking (including an interface for valve actuation of the ESP-hev system outlet valve). In addition, at least one electric traction motor (TM1, TM2, TM3) is integrated in the FDS. At least one further interface is provided between the central computer and the traction motor, preferably an IntTM between the M-ECU and the auxiliary control unit of the respective traction motor (S-ECU-TMi). i interface, or between the M-ECU and the vehicle (IntTM HA 、IntTM VA ), in particular when the axle is equipped with several traction motors. This configuration is advantageous, for example, if a traction motor is provided for each wheel on the rear axle to accelerate or brake the wheel individually.

[0054] One or more of the communication interfaces may be an electrical connection, a wireless connection, or an optical connection, wherein preferably two communication paths are selected. The first communication path may be redundant, and the second communication path may be used to check the signal of the first communication path. In one embodiment, two different types of signal transmission are used to implement the "two out of three principle" so that the Society of Automotive Engineers (SAE) Level 5 standard requirements are met and errors in the transmission process can be eliminated. For SAE Level 4 with an electric pedal or SAE Level 5 without a pedal, the "two out of three principle" is mandatory because there is no longer a brake pedal accessible to the driver.

[0055] Furthermore, the main control unit can also control the solenoid valve driver of the inlet valve of the first pressure supply unit. This means that, regardless of the operating capabilities of the pressure generator (e.g. pump) and the auxiliary control unit of the first pressure supply unit, only the second pressure supply unit and the dedicated solenoid valve on the wheel brake can be used for pressure control for the wheels, in particular for implementing 4-channel ABS or wheel-specific braking torque intervention for steering functions. In one embodiment, the solenoid valve driver, in particular the dedicated solenoid valve, is designed to be redundant.

[0056] In one embodiment, the auxiliary control unit of the first pressure supply unit is equipped with solenoid valve electronics which are electrically isolated from the main control board which has its own independent supply voltage and can therefore operate independently. In this way, a fully functional ABS can be achieved even in the event of a complete failure of the first pressure supply unit.

[0057] Furthermore, the implementation of a central vehicle dynamics control in the domain of a central computer with chassis control can be simplified by integrating the steering actuators (e.g. electric power steering and electric traction motors). The existing software architecture can be essentially retained and overall additional functions requiring the interaction of the steering actuators and the electric traction motors can be easily implemented, for example, in the main control unit. In one embodiment, the functionality of the first pressure supply unit is transferred to the main control unit so that the first pressure supply unit is designed only as a pressure actuator.

[0058] As the central vehicle power control system for a vehicle, the driving power system FDS may include several components listed below: a main control unit (M-ECU) for detecting and / or generating steering commands and braking commands; Wherein, at least one of the ABS function, the ESP function, the TCS function, the ACC function, the AEB function, the energy recovery braking function, and the steering function in the main control unit has redundant microcontrollers μC1, μC2, μC3; at least one electric traction motor TM1, TM2, TM3 for driving and braking the wheels, each of which is equipped with an auxiliary control unit (ECU-TM1, ECU-TM2, ECU-TM3) or a vehicle axle control unit (ECU-VA, ECU-HA); at least one brake module (BM1) hydraulically connected to a plurality of wheel brakes; A central vehicle model, with the aid of which steering and braking commands can be calculated taking into account the road surface friction coefficient, the vehicle speed and / or the dynamic weight distribution of the vehicle during braking. Therein, at least the data of the wheel speed sensor and preferably other sensors (acceleration sensor and / or weight sensor) will be read into the main control unit for braking and steering.

[0059] The driving dynamics system FDS is characterized in that the main control unit (M-ECU) sends steering commands and braking commands for braking torque modulation (e.g. ABS, ESP, EBD) to several auxiliary control units in the following way: The electric traction motor or the BM1 or BM2 brake module provides the basic braking torque, and the braking torque modulation (e.g. ABS, ESP) is controlled via the electric traction motor; or the braking torque modulation is controlled jointly by at least one electric traction motor and at least one brake module (BM1 or BM2); Alternatively, the braking torque modulation on the rear axle is controlled via the electric traction motor, and the braking torque modulation on the front axle is controlled via at least one electrohydraulic brake module (BM1, BM2).

[0060] The advantages of FDS can be fully utilized to optimize the brake unit according to the braking situation (comfort braking, emergency braking), road conditions (braking on asphalt, snow, ice, friction coefficient μ mutation, m separation braking) and the availability of brake modules, so as to maximize the regeneration and brake control performance in different driving situations. In addition, the control of FDS and regenerative braking through the electric traction motor should reduce the cost of the brake calipers, even at high decelerations of <5m / s. Regenerative braking minimizes the thermal load on the friction brake and can reduce the size of the disc brake on the front axle or use drum brakes on the rear axle.

[0061] During braking torque modulation, at least one braking module (BM1, BM2) and at least one electric traction motor (TM1, TM2, TM3) are simultaneously controlled via a central master control unit, and a braking torque command is distributed to at least one braking module and at least one electric traction motor.

[0062] By designing the brake system with at least one brake module (BM1, BM2) and a dedicated solenoid valve that can preferably be directly controlled by the main control unit, it is possible to implement wheel-specific braking torque interventions by means of control of the main control unit. According to the invention, if a wheel circuit fails, the remaining wheel circuits can continue to operate by closing the dedicated valve of the failed wheel brake circuit. In addition, the TTL time can be minimized via central control of at least one traction motor and at least one brake module.

[0063] The following functions particularly benefit from this embodiment: Highly dynamic (50-180ms) automatic emergency braking (AEB) is achieved through the combined braking torque intervention of the electric traction motor and the brake module; Wheel-specific braking torque intervention for steering assistance (Brake to Steer (BtS)) or driving dynamics (Brake to Torque Vectoring (BtTV)); Vehicle stability at high yaw speeds (ESP function); Regenerative braking on the wheels or on the axles.

[0064] According to the invention, on the basis of a dual-circuit ABS / ESP brake system, new functions can be realized and reliability can be improved by improving the hydraulic structure and replacing fewer components. This results in a three-circuit or four-circuit brake system with significant safety advantages. The driving dynamics system (FDS) can also provide wheel-specific braking torque control via the pressure interface Int-BM1 with the main control unit, wherein wheel-specific or axle-specific braking torque control is achieved via the pressure interface, which is easier to achieve than using a standard ESP unit. The system according to the invention can also adjust the pressure in each wheel brake more accurately and dynamically. With the help of the system of the invention, wheel-specific braking torque intervention can always be implemented on the three wheel brakes, which brings significant advantages in terms of vehicle stability functions and highly dynamic processes (such as AEB with electronic brake force distribution (EBD)).

[0065] The driving dynamics system also meets the redundancy requirements for SAE Level 3-5 autonomous driving (redundant brake boost, redundant ABS and EBD functions). The system can be operated with two pressure supply units (so-called dual-tank brake system with one pressure supply unit each), so that in addition to redundant ABS / ESP functions, the control performance in low friction coefficient (low-μ) conditions is significantly improved compared to the prior art through the interaction of the ESP-X unit with the external pressure generator DV2 (especially as part of the pressure supply unit). Its advantageous integration into the electric vehicle domain architecture of the central computer in the form of a master control unit also aims to improve the emergency braking function (AEB) by synchronously setting the setpoint parameters of the braking torque to the control unit of one or more electric traction motors and setting the setpoint parameters of the braking torque. This can significantly reduce the TTL time.

[0066] Since the braking torque of the electric traction motor acts either on only one axle or on several axles with different braking torques, the brake force distribution (EBD) must also be controlled, that is, the hydraulic braking torque must be distributed differently to the front and rear axles compared to a standard EBD control system. The system according to the invention prevents the rear axle wheels from locking before the front axle wheels, and the front axle wheels can only lock up if the deceleration reaches 0.85g. In the event of wheel locking, the ABS intervenes and the braking torque of the electric traction motor must be taken into account in the ABS control.

[0067] An embodiment of the driving dynamics system according to the invention is characterized in that at least two, preferably four, inlet valves of the first pressure supply unit are replaced by special solenoid valves, which are in the open state when there is no current. Compared with the prior art, the special solenoid valves that prevent passive closing do not have a check valve arranged in a hydraulic path parallel to the inlet valve or integrated in the inlet valve. As already explained in the problem definition of the prior art, the function of the check valve is to ensure a safer reduction of the brake pressure of the wheel brake even in the event of a failure or partial failure of the brake system (e.g., the pressure supply unit). However, in the system of the invention, the check valve can be omitted.

[0068] The above-mentioned object is also achieved by a switching valve. The switching valve can be used in particular in combination with the driving dynamics system already described. The switching valve can be used as an inlet valve (of the ESP system) on the one hand and as an isolating valve of the second pressure supply unit on the other hand.

[0069] The switching valve may include: valve actuator or valve tappet; an armature, which is connected to the valve actuator or valve tappet; An electromagnetic drive device, which has at least one excitation coil, is used to adjust the valve tappet along the longitudinal direction between a valve-opening position and a valve-closing position.

[0070] The switching valve is characterized in that the armature comprises at least one permanent magnet. In one embodiment, this is arranged so that the valve actuator or the valve tappet is held in the valve open position by means of a magnetic force generated by the permanent magnet. Preferably, this magnetic force also acts when the electromagnetic drive is not energized. This enables the switching valve to have a particularly high elastic recovery capacity in the face of passive closing, in particular when a large flow of fluid is passed through the valve.

[0071] The above-mentioned switching valve and various embodiments of the switching valve explained below can all be used as special solenoid valves within the meaning of the present invention.

[0072] In one embodiment, at least one annular permanent magnet or a plurality of permanent magnets are arranged in the armature. The magnetic pole direction of the annular magnet or the plurality of permanent magnets is substantially perpendicular to the longitudinal direction.

[0073] In one embodiment, the annular permanent magnet or magnets are embedded in a material having ferromagnetic conductive properties in the axial and radial directions.

[0074] In one embodiment, the permanent magnet (PM) and / or the adjacent ferromagnetic flux guide are arranged and dimensioned in such a way that when the electromagnetic actuator is de-energized, the magnetic force moves the valve tappet from the valve closed position to the valve open position. Thus, this is a power-off-open valve that automatically opens in the event of a power failure. This is particularly advantageous, especially in combination with the above-mentioned driving dynamics system.

[0075] The electromagnetic drive device can include a first excitation coil and at least one second excitation coil. There are thus redundant excitation coils, which are preferably connected to a separately designed electromagnetic valve driver. This generally increases the reliability of the valve. In addition, the valve can be connected to different control units, for example to one of the auxiliary control units and the main control unit. This means that if one of the control units fails, the other control unit can take over the control of the valve.

[0076] In one embodiment, an H-bridge with four switches, in particular power semiconductors, is provided, through which electromagnetic fields with different polarizations can be generated, so that when the excitation coil is energized, the valve can be actively closed and opened according to the wiring mode of the H-bridge and the direction of the current through the excitation coil generated thereby, and during pressure increase and pressure reduction, the valve can be operated independently of the flow direction of the fluid by means of current control with variable cross-section. The H-bridge can reverse the electromagnetic field in at least one excitation coil and can also adjust the magnetic field strength. This allows the force acting on the armature (in the effective direction) and its magnitude to be adjusted.

[0077] In an (alternative) embodiment, the switching valve advantageously provides a novel and at the same time inventive, cost-effective design having a first soft iron magnetic circuit EM1 and a second magnetic circuit EM2 generated by permanent magnets, wherein, in one embodiment, the forces of these two magnetic circuits EM1 and EM2 act on the armature of the ball seat switching valve.

[0078] By using most of the components of a standard solenoid valve (such as the armature diameter and the magnetic circuit with the coil) and only modifying the end (head) of the valve, some switching valves in the present invention can be manufactured at a lower cost.

[0079] The head of the valve is provided with a permanent magnetic circuit, which means that the dedicated solenoid valve combines in one valve a soft iron magnetic circuit (EM1) and a second magnetic circuit (EM2) generated by a simple permanent magnet. This embodiment has the great advantage that it can be manufactured using existing production facilities. The inlet valve, preferably with a constant diameter and with the same interface as the hydraulic block (HCU), can simply be replaced by the dedicated solenoid valve using typical press-fit assembly techniques, i.e. the dedicated solenoid valve can be easily inserted into the unchanged hydraulic block. In addition, the auxiliary control unit (ECU) mounted on the hydraulic block and carrying the excitation coil of the solenoid valve does not need to be modified or only requires minor modifications.

[0080] Typically, the brake module BM1 with the above-mentioned dedicated solenoid valve (ESP-X) can be used in the following various configurations (AE): A) Configuration A: Braking module BM1 (e.g. as ESP-X), hydraulically connected to a vacuum brake booster; B) Configuration B: brake module BM1, hydraulically connected to an electric brake booster, as described, for example, in German patent application DE112009004636B4; C) Configuration C: Braking module BM1, hydraulically connected to an electro-hydraulic brake booster with a pedal feel simulator; D) Configuration D: brake module BM1, hydraulically connected to a second brake module BM2 and controlled via a main control unit and an electronic brake pedal; E) Configuration E: Braking module BM1 as an independent pressure control unit, controlled via a main control unit, for example as an axle module for actuating two wheel brakes or as a central hydraulic device for actuating four wheel brakes.

[0081] All configurations AE are possible using dedicated valves with anti-passive closing function (disconnection of the wheel brake circuit by closing the dedicated solenoid valve): Leakage diagnosis by measuring the pressure increase or volume flow during the pressure increase process by the pressure supply unit when the valve is closed; Diagnose wheel brake circuit faults by measuring the pressure rise or volume flow when the valve is open and comparing it with a typical pressure-volume characteristic curve of the wheel circuit previously measured and stored in memory; Determines whether the wheel brake circuit continues to operate even in the presence of a minor leak; It was decided to disconnect the brake circuit of the failed wheel by permanently closing the valve connected to that brake circuit and to continue operation on three wheel brake circuits; Selective pressure reduction via outlet valve or dedicated solenoid valve; In the other wheel brakes, the wheel brake pressure is maintained at a lower brake pressure level.

[0082] Furthermore, if, for example, a solenoid coil or a solenoid valve driver of a normally closed outlet valve fails, the pressure can be reduced via the inlet valve instead, which increases the availability of the driving dynamics system FDS.

[0083] Since this dedicated solenoid valve is particularly important for function and safety, it is advantageous if this valve has redundant coils and solenoid valve drivers in addition to the anti-passive closing design. In the case of a normally closed outlet valve, this redundancy can be omitted for cost reasons, because if the outlet valve fails, the pressure can still be reduced via the dedicated solenoid valve. This ensures a redundant pressure boost function. The possibility of wheel brake circuit failure is greatly reduced, and the driving dynamics system can operate with high reliability with all wheel brake circuit channels. Redundancy is particularly important in the case of wheel-specific braking torque control, especially in the case of central vehicle dynamics control via the main control unit, such as for BtS and BtTV functions.

[0084] In one embodiment of the invention, the known pressure control method can remain unchanged, while the pressure increase is achieved by pre-pressure control and operation of the inlet valve with a variable valve opening cross section. The solenoid valve is operated by current control or current control as a proportional valve (referred to in the technical field as PWM operation of the inlet valve).

[0085] In a (further) embodiment, the new degree of freedom in the control strategy can be used for pressure control. This allows the functionality of the ABS operation to be improved and also enables new functions, such as wheel-specific braking torque intervention via a pressure interface to the central computer. New functions of the central vehicle dynamics control include, in particular, wheel-specific braking torque control for torque vectoring (BtTV), braking torque intervention for ESP functions or steering functions (BtS) and / or yaw rate control for axle-specific or wheel-specific regenerative braking.

[0086] In one embodiment (valve connection variant I), the valve seat of the inlet valve, in particular a dedicated solenoid valve, is connected to the brake circuit and the armature chamber is connected to the wheel brake. Pressure control method A (e.g. standard pressure setting mode or EV PWM / AV Δt -pressure control method), that is, the traditional pressure control method, in which the inlet valve is PWM controlled during the pressure increase period and the outlet valve is time controlled during the pressure decrease period (Brake Manual Figure 20.12.a).

[0087] Alternatively, due to the use of an inlet valve that prevents passive closing, the pressure control method B (multiplexing / PPC control method, also referred to below as "dedicated pressure setting mode I") can also be used for connection variant I. As shown in the fifth edition of the Brake Manual, Chapter 20.4 "Integrated Brake System (IBS)" - Figure 20.13, the multiplexing / PPC method has great advantages in ABS control on low friction coefficient roads, because the pressure reduction is carried out through the piston-cylinder unit, and the pressure reduction gradient is not limited by the back pressure of the accumulator chamber, so that a smaller reduction in the wheel speed of the locked wheel can be achieved. The inlet valve that prevents passive closing, especially the inlet valve in the form of a dedicated solenoid valve, is used in the same way as the switching valve shown in Figure 20.12.b of the Brake Manual. Another pressure supply unit, for example a second pressure supply unit, is advantageously used as a pressure source and pressure sink. The second pressure supply unit may include a piston-cylinder unit or a rotary pump, wherein the piston of the piston-cylinder unit advances during pressure increase and retracts during pressure reduction, or the rotation direction of the pump motor of the rotary pump changes during pressure increase (p auf ) and pressure reduction (p ab ) period.

[0088] For the pressure control according to pressure control method B and the use of a piston-cylinder unit, the "piston pressure control" (PPC) method known in the professional field can be used, in which pressure increases and decreases can be achieved highly dynamically by using the sensor signal current, the piston position and the pressure-volume characteristic curve. This method can also be used to accurately control the pressure curve that changes over time. The inlet valve can remain open during the pressure change and the pressure curve is preferably controlled only by volume control via the piston-cylinder unit (via a controller cascade with piston stroke, piston speed and electric motor current) or by (current-proportional pressure control). During the pressure increase, the inlet valve can use the multiplexing / PPC method (pressure control method B: p auf / p ab : Multiplexing / PPC method) and PWM control (p auf :EV PWM ;p ab (1) EV Δt , p ab (2) AV Δt The invention also provides a method for controlling the braking pressure of the wheels of the vehicle in a time-controlled manner or a method for controlling the throttle pressure in sequence. This means that the driving dynamics system of the invention can be used to simultaneously set different brake pressures on different wheel brakes with high precision.

[0089] In one embodiment, it is possible to switch between pressure control method A (standard pressure setting mode) and pressure control method B (dedicated pressure setting mode I) during operation. Preferably, switching between the pressure control methods is performed so that pressure control method A is used for ABS pressure control on asphalt roads (high-μ) or in the case of sudden changes in the friction coefficient (μ-sudden changes), where high pressure changes must be achieved simultaneously on multiple wheel brakes. Pressure control method B is preferably used in the case of low friction coefficients, for example on snowy / icy roads (low-μ). The main control unit is preferably designed to be able to detect different conditions. In one embodiment, provided that the main control unit is configured accordingly, one brake circuit of the driving dynamics system can be operated using pressure control method A, while a second brake circuit is operated using pressure control method B.

[0090] In another embodiment (valve connection variant II), a dedicated solenoid valve with a valve seat is connected to the wheel brake, whereby the pressure can be reduced in a throttled manner by means of a variable valve opening cross section. In this embodiment, the pressure can be increased simultaneously or sequentially by means of a second pressure supply unit, preferably by moving a piston and by time control (rather than PWM operation using a multiplexing / PPC method). In this embodiment, the control / regulation strategy of the first pressure supply unit or the main control unit is adjusted so that during the pressure reduction, the second pressure supply unit is used as a controllable or adjustable pressure sink and pressure source. The pressure difference with the wheel brake pressure can be detected by determining the piston position and adjusted accordingly. With this valve connection variant II, one or more outlet valves can also be omitted. For example, four dedicated solenoid valves can be used as de-energized open inlet valves and two de-energized closed outlet valves on the front axle. In this way, no outlet valve is required on the rear axle. Such a system is characterized by high dynamic performance and low noise level.

[0091] In valve connection variant II, the present invention can use the third pressure control method C (p auf :EV Δt , p ab (1) EV PWM , p ab (2) AV Δt In one embodiment, the pressure is increased by pressure control method B (multiplexing / PPC pressure control) or pressure control method C.

[0092] This results in implementations using different pressure control methods, which are summarized in the table below.

[0093] According to the invention, a pressure increase (p auf ) and pressure reduction (p ab As an example, it is possible to pass only through the inlet valve (EV) (see the first column of the table with "p auf (EV)”) and can only be achieved via the outlet valve AV (see the first column of the table with “p ab (AV)” line) to achieve pressure reduction.

[0094] However, redundancy is provided as shown in the table, wherein preferably redundant solenoid coils and redundant drives are provided for the inlet valves as a redundant configuration for the pressure increase (see the first column of the table with "p auf (EV), Redundant Solenoid / Driver" row).

[0095] In some embodiments, the outlet valve (see the first column of the table with "p ab (AV)”) or inlet valve (see the first column of the table with “p ab (EV)”) to ensure redundant configuration for pressure reduction. Without these redundant configurations in terms of hardware and software, pressure reduction via the outlet valve would not be possible if, for example, the solenoid coil of the outlet valve failed, since the valve would be closed when there was no current, thus preventing pressure reduction. This could result in permanent blocking of the relevant wheel brakes.

[0096] The driving dynamics system of the present invention has a general advantage that it is easier and more efficient to implement brake torque intervention for each wheel and a new control strategy for regenerative braking. Unlike the prior art, at least in some embodiments, a dedicated solenoid valve can be used to maintain the pressure in the brakes of selected wheels while changing the brake pressure in other wheel brakes.

[0097] If the pressure is reduced by means of a dedicated solenoid valve, in contrast to the conventional method of reducing the pressure by means of an outlet valve, the pump of the first pressure supply unit must be controlled in order to restore the pressure. This applies in particular to the embodiments to which the above-mentioned configurations (C) and (D) relate. However, in the case of ABS operation with a low coefficient of friction ("low-μ"), the method is also feasible in configuration (B). Configuration (E) also has corresponding advantages if a controllable or adjustable pressure well, such as in the form of a rotary pump, is provided in a certain embodiment of the first pressure supply unit and the pressure well is able to reduce the pressure by reversing the direction of rotation.

[0098] The object mentioned at the outset can be further achieved by a method. In particular, the object can be achieved by a method for regulating the brake pressure of at least one wheel brake in a brake system, the method comprising the following steps: determining to reduce the pressure in at least one of the wheel brakes, namely, the target wheel brake; Selecting a buck mode from a first buck mode and a second buck mode; when the first pressure reduction mode is selected, opening at least one of the outlet valves associated with the target wheel brake to perform pressure reduction; When the second pressure reduction mode is selected, the outlet valve associated with the target wheel brake is kept in a closed state, at least one inlet valve associated with the target wheel brake is opened, and a pressure difference is formed (externally), preferably in a second pressure supply unit, so as to reduce the pressure in the target wheel brake through the inlet valve.

[0099] Therefore, one aspect of the invention is that different modes can be selected according to the specific situation to achieve the best pressure reduction effect. In at least one mode, the pressure is reduced by a (dedicated) inlet valve. On the one hand, this can improve availability (for example, it can still operate in the event of a partial valve failure); on the other hand, the pressure fluctuations during pressure reduction are smaller, and thus the noise is lower, that is: If the outlet valve fails (the outlet valve is closed when the power is off), pressure can also be applied; The pressure reduction process can be regulated or controlled by an external pressure source according to a pressure gradient and / or a pressure gradient profile; If valve connection variant II is selected, the pressure can be reduced smoothly via a special valve.

[0100] In the context of the present invention, keeping a valve closed, especially an outlet valve closed, does not necessarily require actuating the valve in any way. On the contrary, according to the present invention, a normally closed valve, which is often used as an outlet valve, can be kept closed by not applying current and not outputting any type of activation signal.

[0101] Alternatively, the above object can be achieved by a method for performing ABS braking in a vehicle, wherein the method comprises: determining a required pressure reduction gradient for at least one wheel brake; Selecting a pressure setting mode from a plurality of pressure setting modes using a desired pressure reduction gradient, wherein the plurality of pressure setting modes at least include a first pressure setting mode and a second pressure setting mode; If the first pressure setting mode is selected, reducing the pressure of at least one wheel brake via at least one outlet valve using a timer; If the second pressure setting mode is selected, the wheel brakes are depressurized only via a further solenoid valve (particularly when the outlet valve is closed), wherein the wheel brake pressure is transmitted via the further solenoid valve to a controllable / regulatable pressure well.

[0102] Therefore, the mode for depressurization is selected according to the required depressurization gradient. In addition, or as an alternative, factors such as the amount of fluid to be depressurized or the pressure difference may also be considered when making a selection.

[0103] As already explained, the first pressure setting mode may be a standard pressure setting mode. The second pressure setting mode may be a dedicated pressure setting mode I.

[0104] In one embodiment, the plurality of pressure setting modes include a third pressure setting mode, such as dedicated pressure setting mode II. When the third pressure setting mode is selected, the pressure reduction of at least one wheel brake can be performed in parallel at least temporarily by at least one outlet valve associated with the wheel brake and at least one further solenoid valve associated with the wheel brake. The further solenoid valve can be a dedicated solenoid valve, as described in conjunction with various embodiments. By at least temporarily using the inlet valve and the outlet valve simultaneously for pressure reduction, the pressure can be reduced quickly and efficiently.

[0105] In one embodiment, when the second pressure setting mode is selected, a low pressure is set in the pressure well, for example less than 5 bar, preferably less than 3 bar.

[0106] The object mentioned at the outset is also achieved by a main control unit having instructions for carrying out at least one of the methods.

[0107] Furthermore, the object is achieved by a vehicle or a vehicle dynamics system having one of the main control units described, in particular the last-described main control unit.

[0108] Further advantageous embodiments are indicated in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] The present invention is described below by means of several exemplary embodiments, which are explained in more detail with reference to the accompanying drawings. In the drawings:

[0110] Figure 1 shows an ESP hydraulic circuit diagram according to the prior art;

[0111] Figure 2a shows the FDS system architecture with a main control unit for the traction motor and two brake modules BM1, BM2 and multiple auxiliary control units;

[0112] Figure 2b Shows Figure 2a An exemplary embodiment of a brake module, wherein the isolation valve is a dedicated solenoid valve;

[0113] Figure 2c A method for connecting a second brake module as a Figure 2b Valve connection variants of dedicated solenoid valves for isolation valves;

[0114] Figure 3a shows a schematic diagram of the first brake module BM1, in which the two inlet valves of the brake circuit are equipped as dedicated solenoid valves (with a 3-channel braking torque modulation function) to prevent passive closing;

[0115] Figure 3b A schematic diagram of a first brake module connected to a second brake module is shown, wherein four inlet valves of two brake circuits in the first brake module are equipped as dedicated solenoid valves (with a 4-channel braking torque modulation function) to prevent passive closing;

[0116] Figure 4a A schematic diagram of a special solenoid valve with a permanent magnet and a return spring is shown;

[0117] Figure 4b A displacement-force diagram is shown to illustrate the forces acting on Figure 4a The force on the valve actuator of the dedicated solenoid valve shown in;

[0118] Figure 5a shows a schematic diagram of a special solenoid valve with a permanent magnet integrated in the valve armature, wherein the armature can be actuated by electromagnetic fields with different polarizations;

[0119] Figure 5b A displacement-force diagram is shown to illustrate the forces acting on Figure 4a The force on the valve actuator of the dedicated solenoid valve shown varies with the applied current;

[0120] Figure 6 Shown as a basis Figure 5a The H-bridge of the dedicated solenoid valve driver is used to generate electromagnetic fields with different polarizations;

[0121] Figure 7a Shows Figure 3b A schematic diagram of a modification of the illustrated embodiment example without a USV valve (with 4-channel braking torque modulation function);

[0122] Figure 7b Shows Figure 3b Schematic diagram of an improved scheme of the embodiment example shown in , in which there is no USV valve and a check valve is used to replace the HSV valve (with a 4-channel braking torque modulation function);

[0123] Figure 8a A schematic diagram of a first brake module for two wheel brakes with a single piston pump is shown, wherein the two inlet valves are designed as dedicated solenoid valves (which can reduce pressure in the accumulator chamber);

[0124] Figure 8b Shown according to Figure 8a A schematic diagram of an improved scheme of the illustrated embodiment example, which adopts a multi-piston pump (pressure reduction to the reservoir);

[0125] Figure 8c Shown according to Figure 8a Schematic diagram of an improved scheme of an example of an embodiment, which uses a rotary pump instead of a piston pump (depressurization to the fluid reservoir is carried out by means of an outlet valve and / or by using a controllable / adjustable rotary pump as a dedicated solenoid valve for the pressure well).

[0126] Fig. 9 Shows Figure 7b Schematic diagram of a development of the exemplary embodiment shown in , in which there is only one hydraulic connection for the second brake module.

[0127] Fig.10 Shows Fig. 9 The illustrated embodiment shows a schematic representation of a development in which there is no accumulator chamber.

[0128] Fig.11 A schematic diagram visually illustrates the control strategy for the inlet valve;

[0129] Fig.12 A schematic diagram intuitively illustrates the control strategy for the outlet valve;

[0130] Fig.13a Shows the Figure 3a A schematic diagram of a first brake module in combination with an electrically driven piston-cylinder unit as a second brake module, wherein a depressurization of two wheel brakes is presented;

[0131] Fig.13b Shown according to Fig.13a Schematic diagram of an embodiment example of , in which a pressure drop in two wheel brakes is visualized;

[0132] Fig.14 Shows Figure 3b Schematic diagram of a first brake module in combination with an electrically driven piston-cylinder unit as a second brake module, wherein a pressure drop is visualized;

[0133] Fig.15 Shows the Figure 3bSchematic diagram of a first brake module in combination with a centrifugal pump as a second brake module, wherein the pressure drop is visualized. DETAILED DESCRIPTION

[0134] Figure 1 The hydraulic circuit diagram of the first brake module BM1 is shown, and the first brake module is designed as a standard ESP unit. The first brake module BM1 assumes the function of the first pressure supply unit. The first brake module BM1 includes: four time-controlled outlet valves AV1-AV4, each outlet valve being assigned to a corresponding one of the wheel brakes RB1-RB4; four PWM-controlled inlet valves EV1-EV4, each of which is assigned to a corresponding one of the wheel brakes RB1-RB4; Four non-return valves are arranged, each of which is arranged parallel to one of the inlet valves EV1-EV4 and is therefore also assigned to a corresponding one of the wheel brakes RB1-RB4. Depending on the pressure conditions, the non-return valves are arranged so that: when the pressure in the wheel brakes RB1-RB4 increases, the non-return valves are closed, and when the pressure decreases, the non-return valves are opened. In addition, when the valves USV1, USV2 are closed, the valves HSV1, HSV2 enable the delivery of brake fluid via the pump P driven by the motor M, so that the pressure is increased. Finally, the pump P and the motor M form a double-piston pump (first pressure generator DV1), in which each piston is used for the first brake circuit BK1 and the second brake circuit BK2. The accumulator chamber Spk allows the brake fluid to be absorbed via the outlet valves AV1-AV4 during pressure reduction. The arrows in the figure show the possible flow directions of the brake fluid during pressure increase and pressure reduction.

[0135] Figure 1 The first brake module BM1 shown provides the ESP and ABS functions. The ESP function is well known and described in detail in the relevant literature; it requires twelve solenoid valves. For the ABS function, only inlet valves EV1-EV4 and outlet valves AV1-AV4, i.e. eight solenoid valves, are required. The first brake module BM1 has two brake circuits BK1, BK2, which are connected to the second pressure supply unit via two connection points. This may be one of the following situations: 1. Vacuum brake booster of the prior art; 2. Electric follow-up brake booster and brake pedal; 3. Brake booster and brake pedal with pedal feel simulator; 4. A second pressure generator DV2 with a valve.

[0136] Figure 1 A first pressure supply unit a has a pressure sensor p / u which is configured to detect the pressure in brake circuit BK1 .

[0137] The various functions of modern driving dynamics systems are shown in the table below.

[0138] Figure 2a The architecture of the driving dynamics system FDS according to the present invention is shown. The driving dynamics system is equipped with a first and a second traction motor TM1, TM2 on the rear axle HA of the vehicle, and a third traction motor TM3 on the front axle VA of the vehicle. The system can have a brake module BM1 and an optional additional brake module, such as a second electro-hydraulic brake module BM2. A key element of the driving dynamics system is the main control unit M-ECU chassis domain, referred to as M-ECU, which controls the braking torque of the traction motors TM1, TM2, TM3 and the brake modules BM1, BM2, and is used to perform at least one of the following functions: A) Emergency Braking AEB with synchronized electronic brake force distribution (EBD); B) Regenerative braking on the axle or on the wheels; C) Braking operation is performed by the electric motor when the brake module fails; D) Wheel-specific braking torque intervention for steering assistance or vehicle stabilization.

[0139] The main control unit M-ECU sends setpoint values ​​to the individual units, wherein these setpoint values ​​include in particular a brake setpoint torque or a brake setpoint pressure. For certain functions, setpoint signals for pressure control or pressure regulation can be specified, such as control signals for solenoid valves and / or for the pre-pressure of the second brake module BM2 with the second pressure generator DV2 during pressure increase or pressure reduction.

[0140] In an exemplary embodiment, the main control unit M-ECU has a control unit M-ECU AD The system interfaces with the autonomous driving domain and evaluates further information that contributes to effective and predictive control. This includes, for example, camera information about the road conditions (snow, ice, rain) or information about the surrounding environment (distance to pedestrians and / or other vehicles).

[0141] Figure 2bThe so-called dual-tank brake system is shown, which includes a first brake module BM1 and a second brake module BM2. The first brake module BM1 has Figure 1 The second brake module BM2 has a similar structure to the first brake module in a and has a series of functions outlined above. The second brake module BM2 has a piston-cylinder unit (also called plunger) driven by a spindle drive. The piston-cylinder unit forms the second pressure generator DV2. Two isolation valves TV1 and TV2 are provided as part of the second brake module BM2, which can separate the brake circuits BK1 and BK2 from the second pressure generator DV2 and enable the core functions to be realized: Brake booster; Automatic emergency brake (AEB); Electric brake force distribution EBD; 2-channel ABS function in MUX / PPC mode.

[0142] In one example embodiment of the present invention, redundant functionality may be provided to meet the requirements of Level 4 and Level 5 autonomous driving.

[0143] Control units are provided in the two brake modules BM1, BM2, hereinafter referred to as auxiliary control units S-ECU1, S-ECU2a, S-ECU2b, which can communicate with one another and preferably have an interface function Int 2BM (e.g. according to the VDA360 interface definition). Due to the communication capability between the brake modules BM1 and BM2 and the (higher-level) control functions of the main control unit M-ECU, the components can cooperate with each other to achieve certain functions, e.g. in a mixed mode, the pressure generator of the second brake module performs pressure increase and pressure reduction operations, while at the same time, the valves in the first brake module, such as the wheel inlet valves EV1-EV4 and the wheel outlet valves AV1-AV4, are also driven simultaneously.

[0144] Braking modules BM1 and BM2 via interface Int BM1 and Int BM2 In connection with the main control unit M-ECU, this enables additional functions such as ABS, ESP, AEB, ACC as well as new areas of functionality such as torque vectoring (BtTV), brake steering intervention (BtS) and energy recovery / regeneration management for the electric traction motors TM1, TM2 and TM3. In this case, the brake modules BM1, BM2 can act as slaves, i.e. pure pressure controllers, and can implement specified setpoints, such as pressure or braking torque setpoints.

[0145] In at least one operating mode, the (main) interface is used for synchronous actuation of the two brake modules BM1, BM2 by the main control unit M-ECU, for example, the piston of the second pressure generator DV2 of the second brake module BM2 is moved, and at the same time one or more solenoid valves of the first brake module BM1 are switched simultaneously. Each brake module is equipped with a separate interface, which makes it possible to interchange the brake modules BM1, BM2 as required, i.e. the brake modules BM1, BM2 can be obtained from different suppliers. Alternatively, only one interface Int can be provided BM1 or Int BM2 , which is communicatively connected to the main control unit M-ECU. In this case, communication with other units is via a standardized interface Int 2BM In an exemplary embodiment, the wheel speed sensors vR1, vR2, vR3, vR4 are redundantly read by at least two control units, for example one of the auxiliary control units S-ECU1, S-ECU2a, S-ECU2b and the main control unit M-ECU, so that the wheel speed signals can always be read through the interface Int BM1 、Int BM2 、Int 2BM to transfer.

[0146] In the exemplary embodiment shown, the second brake module BM2 is driven via a non-return valve RV NF (Alternatively, a solenoid valve may be used instead of the check valve RV NF ) is hydraulically connected to the reservoir VB and preferably has two three-phase connections (2×3) to meet the requirements of level 4 and level 5 autonomous driving, wherein the two three-phase connections are controlled by the auxiliary control units S-ECU2a, S-ECU2b, respectively, wherein current sensors i / u and motor angle sensors α / u are provided, which are preferably also redundantly designed and can be used for high-precision PPC pressure control or pressure regulation by piston position or current. The redundant design of certain components of the second brake module BM2 can increase availability and create a third backup level for SAE level 5 autonomous driving, which is similar to the design of wire control (there are two steering actuators, one of which is equipped with 2×3-phase motor connections and partially redundant electronic devices), for example, in the event of pump motor failure and partial motor failure (failure of the winding of the motor, the power output stage on ECU2a or ECU2b of the second brake module BM2), it is still possible to generate braking torque and perform braking torque control with about 50% of the motor torque. The pressure sensor p / u is preferably arranged at the output of the pressure source of the second brake module BM2, which is mainly used for calibration purposes. However, if the relationship between the BM2 braking torque and the current or piston position can be determined in some other way, pressure regulation or pressure control can be performed even without this pressure sensor. This also provides further redundancy in the system.

[0147] exist Figure 2a In the embodiment shown, two dedicated solenoid valves MV2k are used as (circuit) isolation valves TV1, TV2 in the second brake module BM2. These dedicated solenoid valves MV2k have, in particular, an anti-passive closing function and are designed in such a way that they can be used to increase and release pressure at high flow rates Q. Preferably, these dedicated solenoid valves are suitable for realizing pressure changes for ABS operation under the multiplexing / PPC method in a highly dynamic manner (i.e. pressure gradients >1000 bar / s, preferably >2000 bar / s). These dedicated solenoid valves are designed according to the system specifications, i.e. according to the requirements of being able to withstand the maximum braking pressure and the maximum volume flow, and are designed with the characteristics of anti-passive closing.

[0148] In one embodiment, a dedicated solenoid valve MV2k having a first soft iron magnetic circuit EM1 and a second magnetic circuit EM2 as shown in FIG. 4 or a dedicated solenoid valve MV2k as shown in FIG. Figure 5a The dedicated solenoid valve MV2k shown has a magnetic circuit EM1 and a permanent magnet PM in the armature of the valve. When using a dedicated solenoid valve MV2k with a permanent magnet PM embedded in the armature, an H bridge is preferably used for current control, as shown in reference Figure 6 explained in more detail. The dedicated solenoid valve MV2k can then be operated in a current-controlled manner with a variable valve cross-section during pressure buildup and pressure reduction. This enables low-noise and high-precision pressure control, in particular during pressure buildup and pressure reduction. In the latter embodiment, the magnetic circuit EM1 and the excitation coil SP1 can be used to generate magnetic forces of different magnitudes in the two movement directions. The advantageous positioning of the permanent magnet PM makes it possible to generate a restoring force even in the de-energized state, so that the return spring RF can be omitted. However, according to the present invention, in addition to the permanent magnet PM, at least one return spring RF can also be provided, for example as shown in FIG. 4 .

[0149] As an alternative to the valves shown in FIGS. 4 and 6 , a standard valve with a magnetic circuit EM1 but without a permanent magnet can be referred to the prior art in a single-box brake system (DE 10 2013 222 281 A1), namely Figure 1 The valves shown by reference numerals 26a and 26b in the figure can also be used as special solenoid valves. According to the present invention, these valves are designed according to the pressure difference and pressure change rate of the functions to be realized (especially AEB function and ABS function). According to the requirements of different functions, electromagnetic circuits with larger armatures and / or stronger return springs can be used.

[0150] The first brake module BM1 operates independently in the standard pressure setting mode (pressure control method A), while the brake module BM2 is operated with the pressure control method B. Furthermore, according to the invention, if the ABS is operated in the case of extremely low road friction coefficients (low-μ) and split road friction coefficients (μ-divergent), it is possible to switch between the standard pressure setting mode and a dedicated pressure setting mode I, in which the pressure is reduced by a dedicated solenoid valve and the brake module BM2 is used as a pressure sink with a pressure below 5 bar, in particular below 3 bar.

[0151] This switching option also exists in other embodiments of a brake system with a double brake module having an accumulator chamber and a brake module (see Figure 3a , 3b , 7a and 7b) and are not described separately below.

[0152] Figure 2c The valve seat VS is shown (e.g. Figure 5a The armature chamber AR (shown) and the armature chamber of the isolating valves TV1, TV2 are advantageously connected to the brake circuits BK1, BK2. Figure 5a The second brake module BM2 is hydraulically connected to the pressure generator DV2 of the second brake module BM2 (shown), and the valve seat of the dedicated solenoid valve MV2k is hydraulically connected to the brake circuit. This arrangement allows the valve opening cross section to be set by means of PWM control or current control, in particular during pressure reduction, so that low-noise pressure reduction can be achieved. In this configuration, the pressure increase process is achieved by controlled or regulated volume metering with the second brake module BM2, wherein the isolation valves TV1, TV2 are preferably time-controlled during pressure increase and the pressure increase process is carried out using a multiplexing / PPC method.

[0153] When using Figure 5a When the special solenoid valve MV2k is shown, it is connected via an H bridge (see Figure 6 ) also enables the pressure increase process to be realized with variable valve cross-sections, which avoids dead time in multiplexing / PPC methods and enables synchronous pressure increase without excessive demands on the actuator. In this embodiment, the connection direction is irrelevant because Figure 5a The special solenoid valve MV2k shown can throttle flow in both directions. In addition, it can be operated with a passive closing protection function.

[0154] Figure 3a (ESP-X 3k，12MV，4RB，SK，KP) shows an example of an embodiment of the first brake module BM1 according to the present invention, which in the embodiment is a three-channel brake system with twelve solenoid valves, four wheel brakes RB1-RB4, an accumulator chamber Spk and a piston pump. It differs from the standard ESP system in that the two inlet valves EV1 and EV2 in the first brake circuit BK1 are designed as special solenoid valves MV2k. Since these valves have special anti-passive closing characteristics, the check valve can be omitted (see Figure 1 The parallel structure of the RV).

[0155] In one embodiment, the dedicated solenoid valve MV2k is equipped with redundant solenoid coils MS1, MS2 and redundant solenoid valve drivers, so that redundant operation is possible, or the solenoid valve driver can be controlled via the main control unit M-ECU. In the embodiment shown, the first brake circuit BK1 corresponds to the front axle brake circuit of the vehicle with II braking force distribution. This means that the wheel brakes RB1, RB2 are the wheel brakes of the front axle VA of the vehicle.

[0156] In an alternative embodiment, an X brake circuit distribution can be selected. In the minimum configuration, the inlet valves EV1, EV2 of the wheel brakes RB1, RB2 assigned to the front axle VA can be designed in this embodiment as dedicated solenoid valves MK2k. A significant improvement can be achieved by this modification of the standard brake system, because the 2-circuit brake system becomes a 3-circuit brake system, in which for both wheel brakes (see Figure 3a In the embodiment of the present invention, the wheel brakes RB1, RB2 in the first or second wheel brake RB1, RB2 are provided with redundancy in the pressure increase and pressure reduction process. In contrast to the prior art, if one of the first or second wheel brakes RB1, RB2, for example wheel brake RB1, fails, the corresponding wheel brake circuit can be disconnected by closing the inlet valve EV1 assigned to the failed wheel brake RB1. This means that the remaining three wheel brake circuits, including wheel brakes RB2-RB4, can continue to operate normally. In addition, if the solenoid coil of one of the outlet valves AV1, AV2 fails, redundant pressure relief can be performed via the corresponding inlet valve EV1, EV2. This presupposes that the corresponding driving dynamics system has a controllable pressure well, for example by providing a corresponding second brake module BM2. With this method according to the invention, a significant improvement in the achievable deceleration can be achieved compared to the prior art, because in the event of a failure, either (a) one wheel brake RB1, RB2 on the front axle VA and two wheel brakes RB3, RB4 on the rear axle HA can be used for braking, or (b) two wheel brakes RB1, RB2 on the front axle VA can be used for braking.

[0157] In an exemplary embodiment, the interface between the above-mentioned brake modules in accordance with the German Association of the Automotive Industry (VDA) 360 standard is extended in that, in addition to the interface described in DE 10 2012 211 278 A1, the inlet valves EV1 to EV4 can also be actuated from the outside. This means that if one wheel circuit fails, yaw rate control (ESP), torque vectoring by wheel-specific braking torque intervention (BtTV) and selective braking torque intervention for steering (BtS) can still be implemented with the remaining three brake circuits. This method of the invention also has the advantage that all functions listed in the above table can be retained without major software changes, especially in the first brake module BM1. The software component for the pressure increase must be modified in order to enable the additional function of three-circuit control in the event of a wheel circuit failure. In addition, since the pressure can be maintained at the two above-mentioned wheel brakes RB1-RB4 by means of dedicated solenoid valves, a control strategy that enables the main control unit M-ECU to set the pressure can be implemented with less development effort. In this way, with the aid of specially configured inlet valves EV1-EV4 and by utilizing the second brake module BM2, it is possible to perform pressure increase and pressure reduction operations for each wheel individually. Figure 3b All isolation valves TV1-TV4 shown are implemented as dedicated solenoid valves) or outlet valves AV1, AV2 (using Figure 3a The brake fluid does not need to be recovered by pump P in a time-consuming manner to reduce the pressure. If no recovery operation is required, the complex pressure oscillation compensation of the second brake module BM2 can also be omitted during the recirculation of the first brake module BM1, which has a beneficial effect on reducing noise and wear.

[0158] WO2018234387A1 (pages 23-25) describes a hybrid strategy for a twin-box brake system and can also be used for wheel-specific braking torque control or braking torque control for torque vectoring or steering intervention. With the help of a dedicated solenoid valve MV2k, hybrid strategies or wheel-specific braking torque interventions can be implemented more easily. In addition, a degree of freedom can be created because the pressure in the wheel brakes RB1-RB4 can be maintained if the pressure supply unit of the second brake module BM2 sets different pre-pressures for different wheel brakes.

[0159] In an exemplary embodiment, the first brake module BM1 can be expanded by two non-return valves RV1, RV2, which are part of the connection between the pump P and the reservoir VB of the brake circuits BK1, BK2 (see Figure 3a Compared to the prior art, this enables the pump to achieve fast filling due to the combination with the second brake module BM2, and the filling speed is much faster than the filling process through the valves HSV1, HSV2 and other hydraulic resistances.

[0160] Figure 3b (ESP-X 4k，12MV，4RB，SK，KP ) shows a first brake module BM1 according to the invention as a 4-channel brake system with twelve solenoid valves, four wheel brakes RB1-RB4, an accumulator chamber Spk and a piston pump KP, which differs from the standard ESP in that in the two brake circuits BK1, BK2, all inlet valves EV1-EV4 and the corresponding check valves RV1-RV4 (see Figure 1 a) are replaced by a dedicated solenoid valve MV2k. In this embodiment example, a 4-circuit brake system is produced. This embodiment example creates more degrees of freedom for braking torque control for specific wheels and provides a simple pressure interface for the main control unit M-ECU. By creating a 4-circuit brake system in the first brake module BM1, the division of the brake circuit in the second brake module BM2 can be omitted. For example, as described in WO2020165294A2, the second brake module may include a simple master brake cylinder (HZ) (so-called single-piston master brake cylinder SHZ) and a pressure chamber with only one piston, wherein the master brake cylinder is preferably designed with redundant seals, wherein SHZ only needs to be connected to one brake circuit, such as the front axle brake circuit. If the wheel circuit in the first brake module fails, it is only necessary to ensure that the faulty wheel brake circuit is disconnected when the pump P also fails. According to the present invention, this can be achieved by corresponding inlet valves EV1-EV4, which can be internally and externally controlled. To this end, the dedicated solenoid valve MV2k is equipped with redundant coils and solenoid valve drivers.

[0161] Figure 4a A first advantageous embodiment of a passively closed and bidirectionally effective no-current opening solenoid valve MV2k is shown. According to the invention, the term "bidirectional" is understood to mean that the pressure increase and pressure reduction process is carried out by the MV2k valve. The dedicated solenoid valve MV2k can operate reliably in both flow directions Q, especially at large flow rates (e.g. 100 cubic centimeters per second (cm3)). 3 / s)-120cm 3 / s) and the connection part has a large pressure difference (e.g. 160 bar-220 bar).

[0162] The dedicated solenoid valve MV2k has a typical structure of a solenoid valve, which includes a magnetic circuit EM1, an armature 6, a valve actuator 7, and the valve actuator includes a valve tappet 7a that closes the valve seat VS. In addition, a return spring RF is provided, which has a linear force curve and acts on the valve actuator 7. The return spring pretensions the dedicated solenoid valve MV2k to an initial position ( Figure 4a shown in the position).

[0163] Especially for the large pressure variations and flow ranges mentioned above, the special solenoid valve MV2k ensures that it does not close automatically due to the influence of dynamic flow forces. These are critical when there is high pressure at the armature chamber AR and low pressure at the hydraulic connection acting on the valve seat VS. The fluid dynamic flow generates a force F hyd , which acts on the valve tappet so that it moves in the direction of the valve seat VS. The return spring RF counteracts the dynamic fluid force, but in extreme cases it is not sufficient to actively prevent passive closing under the influence of the dynamic fluid force.

[0164] Electromagnetic circuit EM1 (see Figure 4b ) will generate a magnetic force F that is related to the current and position EM1 =f(i SP ) (the magnetic force acts on the entire stroke s), which can move the armature toward the stop and the valve tappet 7a toward the valve seat VS. The magnetic force curve is nonlinear and increases with the air gap S. Figure 4a ) and gradually increases, especially following the polynomial formula FM EM1 =(S max -s)n, n = 1.4-2 (wherein, as the stroke s increases or the armature 6 and the stopper (ie, s max -s) the air gap S decreases). The magnetic force can be reduced with the current i SP However, the magnetic force can only act in the direction of the valve seat VS, so if the fluid flow Q originates from the armature chamber, it cannot generate the same force as the fluid dynamic force F. hyd If the valve is in the closed position, the valve can remain activated when the pressure acting on the valve seat is energized. If the fluid acts from the side of the valve seat VS, a reaction force is generated, which means that operation with a variable valve opening cross section is also possible, that is, the special solenoid valve MV2k can be operated with a variable valve opening cross section like a proportional valve. In technical terms, this type of control is also referred to as PMW control.

[0165] In order to make the special solenoid valve MV2k have the function of preventing passive closing, a permanent magnet PM is provided in the first variant as a passive additional force device to increase the restoring force F caused by the return spring RF. RF A permanent magnet circuit comprises a permanent magnet PM and a pole plate 10. The permanent magnet is integrated into an additional armature 6a, which is connected to the armature 6 in a non-positively connected manner. The arrangement direction of the magnetic poles is parallel to the longitudinal direction of the dedicated solenoid valve MV2k, so that the magnetic force F generated by the permanent magnet PM PM F RF The combined force, that is, the total force F ges =F PM +F RF .

[0166] Magnetic force F PM The characteristic of the force is that when the valve is in the open state, the force is large and decreases as the stroke s increases. max ), magnetic force F PM Still high enough to perform a conventional armature reset. By appropriate design, the return spring 13 can be replaced if it is also considered that the magnetic force FEM1 generated via the coil SP2 and the main magnetic circuit EM1 is large enough to overcome the reaction force from the permanent magnet or the return spring, which can be achieved by shaping the characteristic curve of the magnetic circuit (EM) accordingly.

[0167] Additionally or alternatively, the additional restoring force of the first magnetic circuit EM1 can also be generated by the second magnetic circuit EM2. The second magnetic circuit EM2 is generated by the current in the second coil SP2, wherein the magnetic field passes through the additional armature 6a, which is preferably made of ferromagnetic material. This means that in this variant, a force is also generated, which is equal to the restoring force F of the return spring RF. RF The same will affect the fluid dynamics F hyd In this variant, the armature 6 is also mechanically coupled to an additional armature 6a.

[0168] In one embodiment example, the return spring RF can be omitted if the force-applying device is dimensioned accordingly.

[0169] A key aspect of the special solenoid valve MV2k is the total force F ges The force changes substantially linearly over the entire stroke. Preferably, the force increases when leaving the starting position or initial position. The characteristic force distribution over the stroke s is as follows: Figure 4b The figure also shows that the special solenoid valve MV2k according to the present invention has a similar structure to the valves conventionally used in the field (see the restoring force F RF ) significantly different force distributions (see Fges ).

[0170] Figure 5a A second advantageous embodiment of a dedicated solenoid valve MV2k is shown, which has an anti-passive closing function, is bidirectionally effective and is of the normally open type. The dedicated solenoid valve MV2k is suitable for the purposes described in the first brake module BM1 (as inlet valve EV1-EV4) and the second brake module BM2 (as isolation valve TV1, TV2).

[0171] The special electromagnetic valve MV2k adopts the typical design of an electromagnetic valve with a magnetic circuit EM1. The special electromagnetic valve has an armature 6, a valve actuator 7 with a valve tappet 7a, and a valve seat VS. In an embodiment, an annular permanent magnet PM is integrated into the armature 6, and the armature 6 is surrounded by a soft magnetic element (flux conductor). The magnetic pole arrangement direction of the permanent magnet PM is perpendicular to the longitudinal direction of the special electromagnetic valve MV2k. Alternatively, a plurality of permanent magnets PM arranged radially can also be provided. The electromagnetic field EM1 is generated by an excitation current flowing through a coil SP1a, which extends in a circular path in a part of the housing of the special electromagnetic valve MV2k. The magnetic circuit EM1 extends to the housing, and its left leg (loop branch) crosses the first air gap via the flux conductor in the armature, and is closed by the right leg (loop branch) across the second air gap, wherein both branches (legs) are arranged on the housing and have magnetic conductivity. The left leg and the right leg are separated by a larger air gap, so that the electromagnetic field does not close directly from the left leg to the right leg. When energized, magnetic poles are formed on the branches (legs) (of the magnetic circuit) which attract or repel the permanent magnet PM depending on the direction of the current (ie, the direction of the magnetic flux) passing through the exciting coil SP1a.

[0172] In an embodiment, the remaining armature 6 is made of a non-conductive electromagnetic material. For example, it can be made of a cheap plastic component, which preferably also includes the valve actuator 7. In the initial position, the armature 6 is positioned so that the flux conductor is closer to the left leg than to the right leg. Thereby, the armature 6 is subjected to the same Figure 4a The magnetic force F PM and / or restoring force F RF The force effect of the magnetic flux conductor is equivalent to the valve-opening force effect. As a result, the return spring RF can be omitted. In addition, the restoring force via the magnetic flux conductor has a smaller tolerance (error range) than the return spring RF, because the design of the solenoid valve circuit is easy to reproduce.

[0173] exist Figure 5a In the embodiment shown, an H-bridge with four power semiconductors (see Figure 6) to control the excitation coil SP1a. This makes it possible to change the direction of the magnetic flux by reversing the direction of the current. As a result, the electromagnetic field EM1 can increase or reduce the force acting on the permanent magnet PM. The magnetic field can also be reversed so that the dedicated electromagnetic valve MV2k is closed. Thus, the armature 6 can be moved to the right or left in the image plane via current regulation or current control.

[0174] The advantage of the described embodiment is that the valve has a very simple construction. Figure 6 As can be seen, the H-bridge contains four power semiconductors and the flux direction can be determined according to the switching mode of the power semiconductors. If the power semiconductors S2 and S3 are switched, the currents i1, i2 generate a first flux direction, so that a north pole is formed on the left leg and a south pole is formed on the right leg, and the armature 6 is magnetically repelled, i.e. the valve is closed. If the power semiconductors S1 and S4 are switched, the current i3 generates a second flux direction, so that a south pole is formed on the left leg and the armature is retracted, i.e. the valve is opened or held in the open position. Due to the control according to the invention via the H-bridge, the restoring force can even be enhanced by the permanent magnet PM, which means that the valve is very resistant to passive closing and can also be opened very quickly. The rapid opening has the advantage that the dead time during the pressure reduction caused by the opening process of the valve (usually 2 ms) can be reduced to less than 1 ms. This enables a rapid pressure reduction without wasting time, which has a beneficial effect on the control quality of the ABS and the braking distance. Furthermore, the cross section of the special solenoid valve MV2k can be controlled very precisely during pressure buildup, and a larger valve opening cross section can be easily realized with this method, which has the advantage that the throttling effect can be reduced at larger valve strokes. With the control according to the invention via the H-bridge, the special solenoid valve MV2k can be operated in a current-controlled manner with a variable valve cross section during pressure buildup and pressure reduction. This enables a particularly low-noise and highly precise pressure control both during pressure buildup and during pressure reduction.

[0175] In one embodiment, the dedicated solenoid valve MV2k is equipped with a large cross section, which significantly reduces the throttling effect during the pressure increase. This allows the time required to reach the blocking pressure to be shortened.

[0176] The described special solenoid valve MV2k offers the possibility of dispensing with several outlet valves AV1-AV4, in particular with two outlet valves at the wheel brakes RB3, RB4 of the rear axle HA, since dual-channel multiplexing operation is easily achievable with such valves.

[0177] Figure 5b The magnetic force F acting on the armature 6 is shown in FIG. EM1(See the variation of bias force VK and restoring force RK) with distance s. Dashed line s max It represents the maximum distance when the valve tappet 7a closes the dedicated solenoid valve MV2k. If the dedicated solenoid valve MV2k is not energized (i=0), a relatively large restoring force will be generated at the starting position (s=0), and this restoring force will decrease as the distance s increases. However, in the closed position (s=s max ; The valve is in the closed state) and there is still a restoring force, which can prevent the valve from accidentally closing passively. When a negative current (i = i3) is passed, a significantly stronger restoring force will be generated within the entire distance s.

[0178] When a weaker forward current (i=i3) is applied, the restoring force only exists at those positions close to the initial position. Once this restoring force is gone, the biasing force acts to force the valve tappet into the closed position. When a stronger forward current (i=i3) is applied, the biasing force acts over the entire stroke s, so that the dedicated solenoid valve MV2k can be closed in a controlled manner.

[0179] Figure 7a (ESP-X 4k，10MV，4RB，SK，KP ) shows another example of an embodiment of the first brake module BM1, in which the valves USV1, USV2 are omitted without causing any functional restrictions. The brake module has four circuits, ten solenoid valves, four wheel brakes and two accumulator chambers Spk. This assumes that the first brake module BM1 operates in conjunction with a second brake module BM2, which supplies two independent brake circuits BK1, BK2 and has isolation valves TV1, TV2 in the form of dedicated solenoid valves MV2k (e.g. Figure 2b ). The isolating valves TV1, TV2 take over the function of the valves USV1, USV2, especially in the event of an ESP intervention. To implement this solution, a further interface is required between the brake modules BM1, BM2. The advantage of this approach is that the throttling resistance between the pressure generator DV2 of the second brake module BM2 and the wheel brakes RB1-RB4 is reduced, so that the system responds faster, which has a positive effect, for example, in the event of an emergency brake.

[0180] Figure 7b (ESP-X 4k，8MV，4RB，SK，KP) shows a first brake module BM1, in which valves USV1, USV2 and valves HSV1, HSV2 are omitted. The brake module has four circuits, eight solenoid valves, four wheel brakes RB1-RB4, two accumulator chambers Spk and a piston pump KP. In order to realize the functions of valves HSV1, HSV2, two check valves RV1, RV2 are provided, which establish a connection with a reservoir VB. This allows costs to be further reduced without limiting the functionality or the scope of functions.

[0181] Figure 8a (ESP-X 2k，4MV，2RB，SK，KP ) shows an example of an embodiment, which is Figure 7b A modification of the exemplary embodiment shown. Only four valves are required for this (two inlet valves, two outlet valves). The first brake module can be used for one axle of a two-wheeled vehicle or a multi-axle vehicle. It is connected to exactly two wheel brakes RB1, RB2, wherein each wheel circuit can be separated individually by a dedicated solenoid valve MV2k used as an isolating valve TV1, TV2.

[0182] If a wheel brake RB1, RB2 fails, the remaining wheel brake circuits can still be operated and can apply or reduce the braking torque. The first brake module BM1 preferably also provides an interface Int to the main control unit M-ECU BM1 , so that the target parameters for the braking torque intervention for a specific wheel can be set directly via the main control unit M-ECU. The first brake module BM1 can operate independently in the standard pressure setting mode (pressure control method A); pressure control method B can also be used when there is an additional pressure supply source DV2. A separately designed pressure generator DV2 or a second brake module BM2 can be hydraulically connected to the brake module BM1 at the connection points A1, A2, or a SHZ can also be connected to it. Figure 2b As shown, in the ABS mode, it is also possible to switch between the standard pressure setting mode and the dedicated pressure setting mode I.

[0183] Figure 8b (ESP-X 2k、4MV、2RB、VB、MKP) shows a further embodiment example of a first brake module BM1 for two wheel brakes RB1, RB2, in which the pressure generator is a pump with multiple pistons. The pressure is discharged directly into the reservoir VB via the outlet valves AV1, AV2. This has the advantage for the control system that the control effect can be significantly improved during low-pressure control, especially during control on icy and snowy roads, because the back pressure of the accumulator chamber SpK does not limit the pressure gradient during the pressure reduction process. In this embodiment, it is not necessary to set to the dedicated pressure setting mode I. In this embodiment, it is not necessary to set to the dedicated pressure setting mode I.

[0184] The first brake module BM1 preferably also provides an interface Int to the main control unit M-ECU BM1 , so that the target parameters of the VMC for the specific wheel braking torque intervention can be specified directly via the main control unit M-ECU. The first brake pressure module BM1 operates autonomously using pressure control method A; with an additional pressure generator DV2, pressure control method B can also be used.

[0185] Figure 8c (ESP-X 2k、4MV、2RB、VB、MKP ) shows a Figure 8a A similar embodiment is shown with a first brake module BM1 for two wheel brakes. A rotary pump RP is provided as a pressure generator DV1, by means of which pressure can be built up and which can also be released by reversing the direction of rotation. The dedicated solenoid valve MV2k, which is arranged as an inlet valve EV1, EV2 and connected to the wheel brakes RB1, RB2, is equipped with redundant excitation coils and redundant drivers. In general, in all embodiments of the invention, it is feasible to equip corresponding redundant devices.

[0186] The two outlet valves AV1, AV2 associated with the wheel brakes RB1, RB2 are hydraulically connected to the reservoir VB for effective pressure reduction. An advantage of an embodiment is that there are several degrees of freedom for pressure reduction, which can be used to increase availability in the event of a partial failure or for improved control and pressure control options. For example, from the perspective of the first brake module BM1, the pressure can be reduced completely independently via the outlet valves AV1, AV2. Furthermore, the pressure can be built up and reduced with the aid of an external pressure generator DV2, which is provided separately or as part of the second brake module BM2. Therefore, this embodiment is particularly suitable for use as a cost-effective axle module and preferably for central control.

[0187] Generally, in all the embodiments described, the rotary pump RP can be used additionally or solely as the first pressure generator DV1 or the second pressure generator DV2. When used as the first pressure generator DV1 in the first brake module BM1, the check valve RV1 between the pump and the reservoir VB can be omitted (see for example Figure 3b ). An advantage of the pressure reduction by the rotary pump RP is that the pressure reduction gradient is not limited by the back pressure of the accumulator chamber Spk and can be used to improve the ABS control performance in low friction coefficient (low-μ) situations even without the external pressure generator DV2.

[0188] like Figure 3b The first brake module BM1 shown preferably also provides an interface Int to the main control unit M-ECU BM1 , so that the target parameters of the VMC for the specific wheel braking torque intervention can be specified directly via the main control unit M-ECU. The first brake module BM1 works independently in pressure control mode A or dedicated pressure setting mode II (rotary pump acts as pressure sink). Pressure control mode B (dedicated pressure setting mode I) can also be achieved by an additional pressure generator DV2.

[0189] Fig. 9 Shows something like Figure 8a Example of an embodiment. In this embodiment, a (single) hydraulic connection is provided for the second brake module BM2. By using a dedicated solenoid valve MV2k on (all) four wheel brakes RB1-RB4, the advantages of a 4-circuit design can be utilized, thereby eliminating the need for a brake circuit separation.

[0190] Preferably, the embodiment also provides an interface Int to a central control unit, preferably in the form of a main control unit M-ECU. BM1 (not shown) so that target parameters for wheel-specific braking torque interventions can be specified externally. The first brake module BM1 described operates independently via pressure control method A and can be expanded by adding a second brake module BM2 to include pressure control method B (dedicated pressure setting mode I).

[0191] Fig.10 Shows the Fig. 9 Another embodiment example after the embodiment shown is modified. This embodiment does not have an accumulator chamber Spk. To achieve pressure reduction, the wheel brakes RB1-RB4 are hydraulically connected to the reservoir VB via outlet valves AV1-AV4. Only one hydraulic connection is provided for connecting the second brake module BM2. This hydraulic design is similar to Figure 8b and Figure 8cThe hydraulic design of the embodiment shown is similar. However, the first brake module BM1 is designed for four wheel brakes. This embodiment is suitable as a central hydraulic pressure regulator, which is controlled via a central computer, such as a main control unit M-ECU.

[0192] The first brake module BM1 has an optional Int to the main control unit. BM1 An interface (not shown) allows the external specification of target parameters for wheel-specific braking torque interventions. It operates independently via pressure control method A and pressure control method B.

[0193] Fig.11 An example of a first inlet valve EV1 is shown, as can be used in some or all of the described embodiments. The inlet valve EV1 is designed as a dedicated solenoid valve MV2k and has redundant coils, each of which is energized by a driver. The first driver (left) is electrically connected to the auxiliary control unit S-ECU1 of the first brake module BM1, in which the corresponding inlet valve is used. The second driver (right) is connected to the two interfaces Int 2BM and Int BM1 , so that the second drive can be controlled by at least one of the auxiliary control units S-ECU2a of the second brake module BM2 and the main control unit M-ECU.

[0194] In an exemplary embodiment, the auxiliary control unit S-ECU1 implements clock control with pulse width modulation, i.e. voltage, to achieve PWM control. A simple switch is sufficient. The control by the main control unit M-ECU or by the second brake module BM2 is preferably implemented by means of current control i=f(t). The H-bridge described above can be used for this purpose. The H-bridge can be used to adjust the current over time and has greater freedom, especially during pressure buildup and (after appropriate design) during pressure reduction, for variable cross-section valve cross-section control. In this way, the pressure can be increased and released smoothly. Depending on the embodiment, the H-bridge can be used as the first driver or the second driver. Alternatively, both drivers can also be operated via PWM control.

[0195] Fig.12 An outlet valve AV1 is shown, which can be used in one or all of the described embodiments. The outlet valve AV1 has redundant coils, each of which is energized via a driver. The first driver (left) is electrically connected to the auxiliary control unit S-ECU1 of the first brake module BM1, in which the corresponding outlet valve AV1 is used. The second driver (right) is connected to the two interfaces Int 2BM and Int BM1, so that the second actuator can be controlled by at least one of the auxiliary control units S-ECU2a of the second brake module BM2 and the main control unit M-ECU. The outlet valve AV is preferably operated in a time control mode, wherein the opening time is controlled by the voltage U=f(t).

[0196] Fig.13a and Fig.13b shows the pressure build-up via the second brake module BM2 ( Fig.13a ) and pressure reduction ( Fig.13b ) situation, to illustrate Figure 3a The functions of the brake modules BM1 and BM2 in the figure are shown in Figure 1. The corresponding volume flows are marked schematically. In the upper right corner are pressure diagrams over time (t), which intuitively present the pressure curves in the wheel brakes RB1 and RB2.

[0197] exist Fig.13a In the embodiment shown, the pressure is established either according to the pressure control method B (ie, MUX) in the multiplexing / PPC method, with a delay time Δt mux Sequentially; either by pressure control method A (i.e. EV PWM ) in which the pressure build-up takes place simultaneously in several wheel brakes RB1, RB2 via a pre-pressure control. In the latter method, one valve (e.g. the inlet valve EV1) is preferably open, while the other valve (e.g. the second inlet valve EV2) is PWM-controlled. Alternatively, for a given inlet pressure, in order to set different pressures in the wheel brakes RB1, RB2, the two inlet valves EV1, EV2 can be operated with different PWM frequencies or current curves for different valve opening cross sections.

[0198] The pressure drop at the wheel brakes RB1 and RB2 is based on Fig.13b Alternatively, according to the pressure control method B (MUX) in the multiplexing / PPC method, a dedicated solenoid valve MV2k is used in a closed hydraulic circuit with a delay time Δt muxThe pressure is reduced sequentially or by means of pressure control method A (standard pressure setting mode) in an open hydraulic circuit via outlet valves AV1, AV2. In this way, the pressure in wheel brake RB1 can be reduced using the multiplexing / PPC method, while the pressure in wheel brake RB2 can be built up in parallel via the outlet valve. If a very rapid reduction in pressure is required, a dedicated pressure setting mode II (not shown) can also be used to reduce the pressure in parallel via an outlet valve and a dedicated solenoid valve. If an outlet valve fails, the pressure control method A on the wheel brake can be switched to the multiplexing / PPC method. Due to the alternatives and degrees of freedom, very good control performance can be achieved in every critical driving situation, and redundant 4-channel operation is also possible.

[0199] Fig.14 FIG. 4 shows the pressure drop in a design of the brake modules BM1 and BM2. Figure 3b The volume flow is schematically marked. In the upper right corner there is a pressure diagram over time (t), which visually presents the pressure curve in the wheel brakes RB1, RB2, RB3, RB4.

[0200] According to the control strategy shown here, the pressure reduction can be controlled according to the pressure control method B in the multiplexing / PPC method with a delay time Δt mux It can also be realized by pressure control method A. In the MUX method, a target pressure is set via the piston-cylinder unit, which is lower than the pressure in the wheel brakes RB1 to RB4. The pressure is reduced to the accumulator chamber simultaneously via the outlet valves AV1-AV4 without delay time, which means that the delay time Δt can be avoided mux This means that the control system is not expected to cause any restrictions in critical driving situations. In addition, the first brake module BM1 can be optimized with regard to noise by controlling larger pressure gradients via the MUX method without any noise-inducing vibrations and by using pressure control method A to achieve smaller pressure gradients.

[0201] Fig.15 The simplest and most cost-effective version of the solution according to the invention with two pressure supply units is shown. Fig.10 As shown, the brake module BM1 is equipped with only eight solenoid valves, of which all wheel inlet valves use dedicated solenoid valves, i.e. a brake module BM1 with four wheel brake circuits is created here. A rotary pump driven by an electric motor is used as the second pressure supply unit instead of a piston-cylinder unit driven by an electric motor. Due to the design of the four-wheel brake circuit, only one hydraulic connection to the brake module BM1 is required. The brake module BM1 can function independently, but in normal control situations, it is best supported by the third brake module BM3.

[0202] In the standard pressure setting mode, the pressure is released into the reservoir via the outlet valve or can also be reduced in parallel or alternatively by a rotary pump. Due to the corresponding rotation direction of the rotary pump, the rotary pump acts as a pressure sink during the pressure reduction. In addition to having a high degree of fault tolerance, this embodiment also provides many degrees of freedom, in particular the option of switching from the standard pressure setting mode (building up pressure by the inlet valve and reducing pressure by controlling the opening and closing timing of the outlet valve) to a dedicated pressure setting mode I and / or a dedicated pressure setting mode II. If the first brake module BM1 fails, the rotary pump will take over the pressure increase function. In the process, the wheel pressure control valve will be controlled via the main control unit M-ECU or another auxiliary control unit S-ECU2a, S-ECU2b, via Fig.11 and Fig.12 The communication interface (Int 2BM 、Int BM1 ) are controlled simultaneously.

[0203] In the foregoing description, the dedicated solenoid valve is (mainly) described as a dedicated solenoid valve with an additional force device, which includes a permanent magnet and / or a second excitation coil and is arranged to provide at least one restoring force acting on the valve actuator or the valve tappet. In at least some of the described embodiments and embodiment examples, the dedicated solenoid valve can be any passive closing-proof solenoid valve. Therefore, it is conceivable to achieve anti-interference capability for passive closing by providing at least one throttle valve, which ensures that the volume flow is kept at a very low level so that the valve does not close.

[0204] Typically, in the control of the pressure supply unit, the passive closing effect can be limited by limiting the pressure difference or, preferably, by means of a throttle valve (not shown), which is preferably installed upstream of the armature connection of the valve connection in the hydraulic line.

[0205] In some variants of the dedicated solenoid valve, the return spring RF can be omitted.

[0206] Furthermore, in at least one of the described embodiments, the driving dynamics system can be designed in such a way that simple application of the core functions via the main control unit M-ECU can be automated in the application of functions during development, in particular due to the high computing power. In at least one of the described embodiments, learning algorithms or artificial intelligence (AI) can be used to assist in the operation of the vehicle. When using artificial intelligence, the main control unit M-ECU is able to take over tasks of application engineers, which they are unable to do due to the very limited performance and memory constraints of the microcontrollers of the prior art (i.e. one of the control / control units of the brake system). For example, the central computer records measurement data during vehicle operation, evaluates them and applies various functions, in particular those functions that are critical to safety, such as ABS, ESP and AEB functions, when the vehicle is running or when the vehicle is stationary (i.e. the vehicle is not moving, when adaptation is not time-critical). Therefore, it is preferably designed as a closed hydraulic system, with pressure build-up and pressure reduction primarily via a pressure supply unit with the aid of a two-way valve, which has the great advantage that nonlinear relationships can be described by suitable sensors with the aid of characteristic curves (e.g. pressure-volume curve, relationship between motor current and brake pressure, relationship between brake pressure and deceleration when the wheel brake is heated) and can be adjusted during operation for the detection of environmental influences (e.g. air in the system, heating of the wheel brake). If nonlinear relationships are mapped in a mathematical function or mapping, the electrohydraulic brake system can also be applied automatically. If AI methods are consistently applied in hydraulic brake systems (EHB), the advantages of the easy-to-regulate or control electromechanical brake (EMB) disappear, and the advantages of the lower manufacturing costs of hydraulic brake systems come into play, because the disadvantages in terms of application costs are largely eliminated. Reference numerals M-ECU Master Control Unit, Central Computer R1-R4 wheels vR1-vR4 Wheel Speed ​​Sensors RB1-RB4 wheel brakes BK1, BK2 brake circuit A1, A2 connection point BM1 First brake module BM1BE Assembly unit for the first brake module DV1 Pressure Generator M Motor P Pump Group Spk Accumulator Chamber S-ECU1 Control unit for the first brake module RP Rotary Pumps KP piston pump MKP Multi-piston pump BM2 Second brake module BM2BE Assembly unit for second brake module DV2 Pressure Generator S-ECU2a Second brake module control unit S-ECU2b Control unit for the second brake module TV1, TV2 Isolation Valves BM3 additional brake module RV, RV1, RV2 Check Valves AV1, AV2, AV3, AV4 outlet valve EV1, EV2, EV3, EV4 inlet valve Valves for HSV1, HSV2, USV1, USV2 ESP devices MV2k Special solenoid valves for pressure boosting and pressure reduction TM1 The first electric traction motor for driving axles or wheels TM2 Second electric traction motor for driving an axle or wheel TM3 Third electric traction motor for driving an axle or wheel VB Reservoir VA front axle HA rear axle FRF Restoring force due to spring FPM Magnetic FEM1, FEM2 Magnetic Force PM Permanent Magnet EM1, EM2 magnetic circuit RF return spring SP1, SP1a, SP1b, SP2 excitation coil 6 Armature 6a Additional armature 7 Valve Actuator 7a Valve tappet 10 Plates 13 Return spring VS valve seat AR Armature Chamber MS1, MS2 Solenoid Coils S Air Gap S1-S4 Power Semiconductors

Claims

1. A driving power system, the driving power system being applied to a vehicle having wheels (R1-R4), comprising: a main control unit (M-ECU) for detecting and / or generating steering commands and braking commands; at least two hydraulically actuatable wheel brakes (RB1-RB4), wherein each of said wheel brakes is respectively associated with one of said wheels (R1-R4); at least one electric traction motor having a traction motor control unit, wherein the traction motors (TM1, TM2) are used to drive at least one of the wheels (R1-R4), and the main control unit is communicatively connected with the traction motor control unit to control the traction motors (TM1, TM2) to execute the steering command and the braking command; At least one first electro-hydraulic pressure supply unit (BM1), comprising: at least one electric pump unit; at least two connecting lines for connecting the wheel brakes (RB1-RB4); Electrically actuatable wheel brake pressure regulating valves or brake pressure regulating valves (AV1-AV4, EV1-EV4); and A first auxiliary control unit (S-ECU1); wherein at least one of the hydraulically actuatable wheel brakes (RB1-RB4) is associated with a brake pressure regulating valve and one of the outlet valves (AV1-AV4), the brake pressure regulating valve being in the form of a dedicated solenoid valve (MV2k), the dedicated solenoid valve having in particular anti-passive closing properties; The driving dynamics system, in particular the main control unit (M-ECU), is configured to release the pressure in the at least one hydraulically actuatable wheel brake via the associated outlet valve or via the dedicated solenoid valve (MV2k).

2. The driving power system according to claim 1, wherein: At least one of the brake pressure regulating valves is a special electromagnetic valve (MV2k), and the special electromagnetic valve (MV2k) has an electromagnetic drive device, and the electromagnetic drive device has a first excitation coil (SP1, SP1a), through which the valve actuator (7) or the valve tappet (7a) can be adjusted between a valve opening position and a valve closing position; wherein the dedicated solenoid valve (MV2k) has an additional force device, the additional force device comprises a permanent magnet (PM) and / or at least one second excitation coil (SP1b, SP2), and the additional force device is configured to provide at least one holding force (FEM2, FPM) acting on the valve actuator (7) or the valve tappet (7a); and / or The main control unit (M-ECU) is configured to actuate the dedicated solenoid valve (MV2k) and the first pressure supply unit (BM1) at least in a selected braking mode, so that when the dedicated solenoid valve (MV2k) is opened, the pressure of at least one of the wheel brakes (RB1-RB4) associated with the dedicated solenoid valve (MV2k) is reduced.

3. A driving dynamics system according to any one of the preceding claims, wherein: The main control unit (M-ECU) is configured to actuate the associated dedicated solenoid valve (MV2k) and one of the outlet valves (AV1-AV4) at least in a selected braking mode, so that the brake fluid is discharged from the wheel brake simultaneously via the associated dedicated solenoid valve (MV2k) and one of the associated outlet valves (AV1-AV4).

4. A driving dynamics system according to any one of the preceding claims, wherein: Also includes: At least one second pressure supply unit (BM2), preferably comprising a piston-cylinder unit or a rotary pump, is configured to provide brake fluid to a first brake circuit (BK1) and a second brake circuit (BK2) at least at one inlet of the first pressure supply unit, wherein preferably at least one isolation valve is provided for isolating the first brake circuit and / or the second brake circuit.

5. A driving dynamics system according to any one of the preceding claims, wherein: The first pressure supply unit (BM1) is directly connected to exactly two of the wheel brakes (RB1-RB4), wherein exactly two of the wheel brakes (RB1-RB4) brake the wheels on the first axle, and / or an additional pressure supply unit (BM3) is provided, wherein the additional pressure supply unit (BM3) is directly connected to at least two of the wheel brakes (RB1-RB4) on the second axle.

6. A driving dynamics system according to any one of the preceding claims, wherein: The dedicated solenoid valve (MV2k) is configured to open when de-energized and is arranged such that a valve seat of the dedicated solenoid valve is directly connected to at least one of the wheel brakes (RB1-RB4).

7. A driving dynamics system according to any one of the preceding claims, wherein: The main control unit (M-ECU) is configured to detect a fault in at least one wheel brake circuit including one of the wheel brakes (RB1-RB4), and to close the dedicated solenoid valve (MV2k) assigned to the one of the wheel brakes (RB1-RB4) so ​​as to disconnect the wheel brake circuit.

8. A driving dynamics system according to any one of the preceding claims, wherein: The first pressure supply unit (BM1) includes a rotary pump connected to the wheel brakes (RB1-RB4) and configured to increase and decrease the pressure in the wheel brakes (RB1-RB4).

9. A driving dynamics system according to any of the preceding claims, in particular according to claim 4, wherein: A dedicated solenoid valve (MV2k), in particular the dedicated solenoid valve (MV2k) assigned to the second pressure supply unit (BM2), is configured such that its valve seat is directly connected to the inlet of the first pressure supply unit (BM1).

10. A driving dynamics system according to any of the preceding claims, in particular according to claim 4 or 9, wherein: During the pressure reduction, at least one of the dedicated solenoid valves (MV2k) is actuated, in particular by PWM control or current control, to provide a variable valve opening cross section.

11. A driving dynamics system according to any one of the preceding claims, wherein: The first auxiliary control unit (S-ECU1) and / or the second auxiliary control unit (S-ECU2a, S-ECU2b) and / or the actuator of the first and / or second pressure supply unit (BM1, BM2) and / or the sensor of the first and / or second pressure supply unit (BM1, BM2) are connected in particular via the communication interface (Interface 1). BM1 、Int BM2 ) is communicatively connected to the main control unit (M-ECU) so as to execute the steering command and / or the braking command.

12. A driving dynamics system according to any of the preceding claims, in particular according to claim 11, wherein: The master control unit (M-ECU) is configured to: The pressure control for the wheel brakes is achieved by activating at least one of the dedicated solenoid valves of the first pressure supply unit and / or at least one second pressure supply unit; and / or detecting a wheel circuit fault by measuring said pressure when a dedicated solenoid valve or an inlet valve of said first pressure supply unit is closed; and / or isolating the faulty brake circuit by closing at least one of the isolation valves (TV1, TV2); and / or Axis-by-axis ABS is implemented by controlling at least one of the isolation valves (TV1, TV2) and alternately increasing and decreasing the pressure via the second pressure supply unit; and / or Implementing ABS for the wheels by controlling at least one of the dedicated solenoid valves (MV2k) and in particular controlling the outlet valve of the first pressure supply unit and alternately increasing and decreasing the pressure via the second pressure supply unit (BM2); and / or During braking using the at least one traction motor, the braking torque generated by the second pressure supply unit (BM2) is distributed axle by axle by controlling the dedicated solenoid valve (MV2K) assigned to the second pressure supply unit; and / or Automatic emergency braking is achieved by actuating the traction motors (TM1, TM2) and at least the first pressure supply unit (BM1) in parallel.

13. A driving dynamics system according to any of the preceding claims, in particular according to claim 2, wherein: The electromagnetic drive device (EM1) adopts a redundant design and is equipped with at least one first solenoid valve driver and one second solenoid valve driver, wherein the auxiliary control unit (S-ECU1) used to control the at least one dedicated solenoid valve (MV2k) is communicatively connected to the first solenoid valve driver, and the main control unit (M-ECU) used to control the at least one dedicated solenoid valve (MV2k) is communicatively connected to the second solenoid valve driver.

14. A driving dynamics system according to any one of the preceding claims, wherein: The master control unit (M-ECU) is configured to at least temporarily regulate the brake pressure in at least some of the wheel brakes (RB1-RB4) in a multiplexing and / or PPC method.

15. A driving dynamics system according to any one of the preceding claims, wherein: The master control unit (M-ECU) is configured for implementing the method according to at least claim 16 .

16. A method for regulating the brake pressure in at least one wheel brake in a braking system, preferably via an inlet valve for admitting brake fluid into the wheel brake and an outlet valve for discharging brake fluid from the wheel brake (RB1-RB4), the method comprising: determining to reduce pressure in at least one of the wheel brakes (RB1-RB4), including a target wheel brake; Selecting a buck mode from a first buck mode and a second buck mode; when the first pressure reduction mode is selected, opening at least one of the outlet valves associated with the target wheel brake to perform pressure reduction; When the second pressure reduction mode is selected, the outlet valve associated with the target wheel brake is kept closed and at least one of the inlet valves associated with the target wheel brake is opened, and a pressure difference is formed externally, preferably in a second pressure supply unit, to reduce the pressure in the target wheel brake via the inlet valve.

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