Fail-safe valve unit, electronically controllable pneumatic brake system, vehicle, method

Abstract

The invention relates to a failsafe valve unit (1) for a fault brake function (FN) of an electronically controllable pneumatic brake system (204) for a vehicle (200), in particular a commercial vehicle (202), wherein the brake system (204) has at least one control unit (410) and the failsafe valve unit (1) has: - a main connection (20) and a fault brake connection (22) which provide a first pressure (p1), - a fault brake valve (40) which is configured as a monostable valve, the fault brake valve is controllable by the control unit (410) or an external control unit (418), and the fault brake valve is configured to - pneumatically connect the main connection (20) and the fault brake connection (22) in an open position (40A) for regulating a fault brake pressure (pN) at the fault brake connection (22). According to the invention it is provided that - in an error condition (FF) and / or a power failure (FS) and / or a diagnostic condition (FT) of the control unit (410), the fault brake valve (40) is in the open position (40A), and - a fault brake (BA) of the vehicle (200) is triggered by the brake system (204) via the provision of the fault brake pressure (pN) at the fault brake connection (22), wherein - the main connection (20) is pneumatically connected to a parking brake function (FFS) for receiving a regulated parking brake pressure (pFS) or a pressure (pFS') derived therefrom as the first pressure (p1).

Description

Technical Field

[0001] This invention relates to a fail-safe valve unit for the fault braking function of an electronically controlled pneumatic braking system for a vehicle. The invention also relates to an electronically controlled pneumatic braking system having a fail-safe valve unit of the type described above. Furthermore, the invention relates to a vehicle having an electronically controlled pneumatic braking system of the type described above. Finally, the invention relates to a method for operating a braking system of the type described above. Background Technology

[0002] In modern, electronically controlled pneumatic braking systems, especially those designed for autonomous driving in commercial vehicles, it is important to provide measures that allow the commercial vehicle to decelerate safely even in the event of a malfunction in the braking system.

[0003] In particular, providing redundancy is a well-established measure for improving safety. Several approaches exist, namely, using fully redundant braking systems, partially redundant braking systems, or using different levels only in the braking system, so that if an error occurs in the first level, the braking system can continue to operate, at least with limitations, in the second level.

[0004] One approach is to provide fail-safe braking functionality by activating the parking brake in the event of an error. The problem here is the time delay in fail-safe braking, which is attributable to the totzeit in the response behavior due to a chain of actions that includes a reversal (relative to the service brakes) of pressure offset that the participating parking brake must overcome.

[0005] Therefore, there are some advantageous solutions based on adjusting the braking pressure to the service brakes when an error occurs.

[0006] A system providing electro-pneumatic control redundancy is disclosed in DE 10 2016 005 318 A1. The system disclosed in this document utilizes a bypass valve to redirect control pressure based on subsystem failures, thereby supplying at least pneumatically to circuits experiencing electrical faults. This also generally and advantageously improves residual availability. Similar systems are disclosed in DE 10 2016 010 462 A1 and DE 10 2016 010 464 A1.

[0007] The concept still needs improvement, especially in reliably providing fail-safe braking and maintaining braking status in fault conditions.

[0008] Therefore, it is worth looking forward to improving the functionality of the fail-safe valve unit. Summary of the Invention

[0009] Based on this, the objective of the present invention is to describe an improved fail-safe valve unit. In particular, it is intended to provide a fail-safe valve unit that reliably provides fail-safe braking in fault conditions and continuously ensures the braking status of the vehicle.

[0010] The present invention is based on a fail-safe valve unit for the fail-safe function of an electronically controlled pneumatic braking system for vehicles, particularly commercial vehicles, wherein the braking system has a control unit, and the fail-safe valve unit has: a main interface and a fail-safe interface that provide a first pressure, and a fail-safe valve configured as a monostable valve, which can be controlled by the control unit or an external control unit and is configured to pneumatically connect the main interface and the fail-safe interface in the open position for regulating the fail-safe pressure at the fail-safe interface.

[0011] According to the present invention, the fail-safe valve unit according to the first aspect of the present invention is provided with,

[0012] - In the event of a control unit malfunction and / or electrical failure and / or diagnostic conditions, the fault brake valve is in the open position, and

[0013] - Failure braking of the vehicle is triggered by providing failure braking pressure through the braking system at the failure braking interface, wherein,

[0014] - The main interface is pneumatically connected to the parking brake function to receive the regulated parking brake pressure or the pressure derived from the parking brake pressure as the first pressure.

[0015] In particular, the electronically controlled pneumatic braking system includes a service brake system and a parking brake system. The parking brake function is configured to pneumatically operate at least one parking brake cylinder.

[0016] The present invention is based on the idea that the braking system, particularly the service braking system, can remain under control via a separate drive control branch (for triggering fail-safe braking in erroneous conditions). Specifically, by providing fail-safe braking pressure, it should be ensured that the vehicle is safely decelerated via fail-safe braking in erroneous conditions.

[0017] This invention incorporates the understanding that maintaining continuous braking of a vehicle is important for vehicle safety. Following fail braking via the fail-safe valve unit, leakage may occur in the service brake circuit (where fail braking was performed), particularly in the control circuit of the pneumatic front axle brake circuit, at the front axle modulator, or elsewhere in a separate drive control branch where the fail-safe valve unit is located. In the event of such leakage (if the connected pressure accumulator is gradually emptied), a drop in fail-safe braking pressure may occur, potentially reducing the effectiveness of fail-safe braking.

[0018] Because the main interface according to the invention is pneumatically connected to the parking brake function to receive the regulated parking brake pressure as the first pressure, it is advantageously achieved that, in the event of leakage after failure braking via the fail-safe valve unit, at least one parking brake cylinder is also pneumatically connected to the leaking portion. Therefore, leakage caused by the fail-safe valve unit according to the invention leads to the engagement of the parking brake, thereby safely maintaining the vehicle's braking state. The engagement of the parking brake is achieved by venting the parking brake cylinder, thereby relaxing the compression spring and applying it to the wheel brakes.

[0019] Therefore, by means of the fail-safe valve unit according to the invention, the pneumatic connection between the service brake circuit (performing fail-safe braking), particularly the front axle brake circuit of the service brake, and the regulated parking brake pressure is specifically utilized so that, in the event of pressure loss, the reduced braking effect of the service brake circuit (performing fail-safe braking) is compensated by the effect produced by the parking brake. This process can be relatively slow, taking anywhere from several hours to several days, depending particularly on the degree of leakage.

[0020] The advantageous improvements of the present invention detail the above-described concept within the scope of the task and advantageous feasible solutions with respect to other advantages.

[0021] In particular, the parking brake system and / or parking brake function includes a parking brake module. The parking brake function is preferably configured to regulate the parking brake pressure for intake of the parking brake cylinder. The parking brake function is preferably provided by the parking brake module. In an improved embodiment, the parking brake function may be provided by another pneumatic or electro-pneumatic device, such as an axle modulator, a trailer control module, or a similar pneumatic or electro-pneumatic device.

[0022] Specifically, the main interface is pneumatically connected to the parking brake cylinder, preferably to two parking brake cylinders respectively located on the vehicle side. More specifically, the main interface is pneumatically connected to at least one parking brake chamber of the parking brake cylinder.

[0023] This invention improves upon the previous one by employing a selector valve having a first interface that is pneumatically connected to a parking brake function, particularly a parking brake system and / or parking brake module, for receiving a first pressure.

[0024] - The selector valve has a second port, which is pneumatically connected to an additional compressed air reservoir to receive additional reserve pressure as a second pressure, and

[0025] - The selector valve has a third interface, which is pneumatically connected to the fail-safe valve, wherein...

[0026] - The selector valve is configured to pneumatically connect the port in the first and second ports that is subjected to higher pressure to the third port, and in particular to block each other port.

[0027] The improved design with a selector valve incorporates the understanding that redundantly supplying compressed air to the fail-safe valve unit advantageously enhances vehicle safety. By means of a selector valve having a first interface pneumatically connected to the parking brake system for receiving a first pressure, the availability of a first compressed air source for providing fail-safe braking pressure can be advantageously provided. This first compressed air source is particularly independent of the compressed air source used in the normal operation of the brake circuit (especially independent of the service brake circuit supplied with fail-safe braking pressure). Therefore, redundancy has been advantageously achieved by using a separate brake circuit.

[0028] By means of a second interface pneumatically connected to an additional compressed air reservoir via a selector valve to receive additional reserve pressure as a second pressure, an additional source of compressed air, independent of the parking brake system, is advantageously provided as further redundancy. This additional compressed air reservoir can, in particular, be the compressed air reservoir of the service brake system.

[0029] Because the fail-safe valve has a third port that is pneumatically connected to the fail-safe valve and the fail-safe valve is configured to pneumatically connect the port of the first and second ports that is loaded with higher pressure to the third port, even if the compressed air source at one of the first and second ports fails, another available compressed air source is automatically connected to the fail-safe valve.

[0030] Therefore, by selecting the valve, the availability of fail-safe braking is further improved, and thus the safety of the vehicle is enhanced.

[0031] In particular, the fail-safe valve is configured to be in the open position when not driven, especially when there is no current. In particular, the fail-safe valve is configured to be monostable.

[0032] Preferably, the selector valve is configured as a shuttle valve, and more preferably as a high-selection shuttle valve.

[0033] The parking brake pressure is specifically regulated or provided by the parking brake module. The parking brake circuit reserve pressure is specifically provided by the compressed air accumulator of the parking brake system. If the parking brake circuit reserve pressure is provided by the compressed air accumulator of the parking brake system, then the parking brake system, especially the parking brake module, is advantageously configured to automatically engage in the absence of reserve pressure in the event of a power outage. In particular, a power outage state exists when the control unit and / or other control units and / or the parking brake module are not powered or fail due to an error condition.

[0034] Preferably, the fault braking pressure is provided as a control pressure for the axle modulator, particularly for the front axle modulator, or as a braking pressure for the brake cylinder. When the fault braking pressure is provided as a braking pressure for the brake cylinder, especially when the brake cylinder is activated entirely by means of compressed air with the fault braking pressure supplied by the fail-safe valve unit, the fail-safe valve unit can advantageously achieve a complete supply of compressed air required for fault braking. When the fault braking pressure is provided as a braking pressure for the modulator, then the fault braking pressure acts particularly on the modulator's control interface, where the modulator particularly enhances the air volume and is supplied particularly by an additional compressed air source or compressed air reservoir. The modulator's control interface is, in particular, a redundant interface for the modulator.

[0035] Preferably, an additional fault braking valve is provided, pneumatically connected in series with the fault braking valve, and controllable by a control unit, particularly an additional control unit. The additional fault braking valve is preferably open when not driven, particularly in a no-current state, so that a first pressure, acting as the fault braking pressure, applied to the main interface is provided to the fault braking interface. In particular, the additional fault braking valve can be controlled via an additional control signal. In particular, the control unit is associated with the main system. In particular, the additional control unit and / or the additional fault braking valve is associated with a first backup level. In the improved embodiment with the additional control unit, even in the event of a double fault, i.e., when both the control unit and the additional control unit are faulty, fault braking can be advantageously ensured by means of the additional fault braking valve. The fault condition can be caused, in particular, by abnormal errors and / or electrical faults. The additional fault braking valve is particularly configured to be monostable. The fault braking valve and / or the additional fault braking valve are particularly arranged in the valve main circuit.

[0036] The invention is improved by configuring the additional fail-safe valve as a 2 / 2 reversing valve, particularly as a 2 / 2 solenoid reversing valve. With this additional fail-safe valve configured as a 2 / 2 reversing valve, the regulated fail-safe pressure can be advantageously modulated, especially by time-controlled opening and closing of the 2 / 2 reversing valve. In particular, graded braking can be ensured in the event of a partial failure or when the control unit still has residual availability, for example, when the voltage supply is still available. Modulation of the fail-safe pressure particularly enables less abrupt fail-safe braking.

[0037] Preferably, the fail-safe valve and / or another fail-safe valve are configured as 3 / 2 directional control valves, particularly 3 / 2 solenoid directional control valves. Specifically, the fail-safe valve and the other fail-safe valve are structurally identical. In particular, the fail-safe valve and / or the other fail-safe valve have a vent port, which is pneumatically connected to the fail-safe valve port in the blocked position. In this way, venting to the fail-safe valve port can be achieved in the blocked position.

[0038] Preferably, a pressure relief valve is provided. This pressure relief valve allows for advantageous adjustment of the pre-defined fault braking pressure to achieve appropriate braking efficiency during fault braking. Preferably, the pressure relief valve is located at the main interface of the fail-safe valve unit or between the main interface of the fail-safe valve unit and the valve immediately following it.

[0039] Preferably, a bistable valve is provided, configured to switch between a first deactivated position (connected to the main valve circuit or the vent section) and a second activated position (connected to the main valve circuit), wherein the bistable valve is pneumatically connected in series with at least one fail-safe valve. The bistable valve allows the fail-safe valve unit to advantageously operate not only in modes suitable for automatic vehicle operation but also in manual operation modes. Specifically, the bistable valve is configured such that, in the first position (connected to the main valve circuit), the main valve circuit is pneumatically connected to the vent section of the bistable valve at the first bistable valve interface and is blocked at the second bistable valve interface; while in the second position (pneumatically connected to the main valve circuit), the main valve circuit is pneumatically connected between the first and second bistable valve interfaces and is blocked at the vent section of the bistable valve. The bistable valve is preferably arranged in the main valve circuit.

[0040] When the bistable valve is in the first position of the main circuit of the shut-off valve, the supply of fault braking pressure at the fault braking interface of the fail-safe valve unit is naturally prevented, regardless of the position of the fail-safe valve. Therefore, in this first position, fault braking caused by double errors can be prevented. This is particularly advantageous when the vehicle is being manually operated, especially when the human driver should maintain control of the vehicle. In contrast, the bistable valve can be switched to the second position of the pneumatically connected valve main circuit, so that (when at least one fault braking valve of the fail-safe valve unit is in the open position) fault braking pressure can be supplied to the fault braking interface to trigger fault braking of the vehicle. According to the concept of the bistable valve, it remains in its switched position, more precisely, even in a state of no current and especially regardless of possible erroneous conditions in the braking system. The bistable valve is controlled, in particular, via a control unit or valve control unit. The valve control unit is connected, in particular, to the control unit of the braking system and / or to the vehicle bus in a signal and / or energy conduction manner.

[0041] Preferably, an additional selector valve is provided, having a first additional interface pneumatically connected to a brake value transmitter for receiving brake value transmitter pressure, particularly pneumatically connected to the pneumatic front axle modulator control circuit; a second additional interface pneumatically connected to a fail-safe brake interface for receiving fail-safe brake pressure; and a third additional interface pneumatically connected to the service brake cylinder or axle modulator. The additional selector valve is configured such that the interface of the first and second additional interfaces, to which higher pressure is applied, is pneumatically connected to the third additional interface, and particularly blocks each of the other interfaces. With the aid of the additional selector valve, fail-safe brake pressure can advantageously be introduced into the service brake circuit in addition to the brake value transmitter.

[0042] Preferably, a pressure sensor is provided, which is located at or pneumatically connected to the fail-safe port 22. The pressure sensor allows for advantageous verification and / or inspection of the reliability of the fail-safe valve unit's function by monitoring pressure responses.

[0043] Preferably, a failover relay valve is provided. The failover relay valve is particularly positioned between one side, which is at least one failover brake valve and possibly a bistable valve, and the other side, which is a failover brake interface. The failover relay valve can advantageously enhance the airflow, thereby allowing the remaining valves of the fail-safe valve unit to be advantageously configured with a smaller nominal size.

[0044] In an alternative improvement, an additional selector valve can be located in other parts of the service braking system, particularly in the pneumatic front axle brake circuit, to directly supply one or more service brake cylinders.

[0045] In a preferred embodiment, an external control unit is provided, which is connected to one or more valves of the fail-safe valve unit, particularly to at least one fail-safe brake valve, by means of conducting signals and / or energy. Specifically, the external control unit is connected to the fail-safe valve unit via alternative control lines and / or other alternative control lines. The external control unit is connected to the control unit by means of guiding signals, particularly via monitoring lines, for monitoring the control unit. The external control unit can advantageously be formed by, or as part of, other electronic control units of the vehicle. Such other electronic control units are, for example, virtual driver control units in the form of automatic operation control units, or electronic control units of steering systems, parking brake systems, or air preparation facilities. With the aid of the external control unit, the function of the control unit, i.e., the function of the control unit of the braking system, particularly the service brake system, can be advantageously monitored. In the event of a malfunction in the control unit, this malfunction can be identified by means of the external control unit. In the event of a malfunction, the external control unit can interrupt the actuation of the valves of the fail-safe valve unit, particularly the actuation of at least one fail-safe brake valve, and particularly trigger the fail-safe brake.

[0046] In a second aspect, the object of the present invention is also to provide an electronically controllable pneumatic braking system for vehicles, particularly commercial vehicles, having a control unit.

[0047] In an electronically controlled pneumatic braking system, a fail-safe valve unit is provided according to at least one preferred embodiment of the fail-safe valve unit according to the first aspect of the present invention, wherein the fail-safe valve unit is arranged in a separate drive control branch and is pneumatically connected via a fail-safe interface to at least one service brake cylinder and / or service brake chamber and / or axle modulator for providing fail-safe braking pressure to the axle modulator to trigger fail-safe braking of the vehicle.

[0048] In braking systems, the advantages of fail-safe valve units are advantageously utilized. "Separate drive control branch" here means that the fail-safe valve unit is arranged in an additional pneumatic drive control branch, which is formed separately from the main pneumatic drive control branch, especially the one with the brake value transmitter.

[0049] In an improved electronically controlled pneumatic braking system, an axle modulator is provided, which has a throttling element, particularly a nozzle orifice, that pneumatically connects a portion of the axle modulator's pilot control pressure to a portion of its pilot working pressure. The pilot control pressure portion of the axle modulator is formed, in particular, by the control circuitry of the axle modulator's control circuitry, and especially by the control circuitry of the axle modulator's relay valve. The pilot working pressure portion of the axle modulator is formed, in particular, by the working circuitry of the axle modulator's working circuitry, and especially by the working circuitry of the axle modulator's relay valve. Specifically, the throttling element is located in the relay piston of the axle modulator's relay valve. With this throttling element, even in the event of leakage in the working circuitry or the portion pneumatically connected to the working circuitry, the engagement of the parking brake can be advantageously ensured.

[0050] In the improved scheme of the electronically controlled pneumatic braking system, the control unit is associated with the main system of the electronically controlled pneumatic braking system, and the electronically controlled pneumatic braking system also has: an additional control unit for a first backup level, wherein a fault brake valve can be driven by the control unit and another fault brake valve can be driven by another control unit, and the first control unit and the second control unit can be supplied with energy independently of each other and / or can at least partially substitute for each other in terms of their functions.

[0051] In a third aspect of solving the problem, the invention also relates to a vehicle, particularly a commercial vehicle, having a braking system according to the invention. In this vehicle, the advantages of a fail-safe valve unit are advantageously utilized. In an improved version of the vehicle, an external control unit is provided.

[0052] In a fourth aspect of solving the task, the invention also relates to a method for operating a braking system having a fail-safe valve unit for failure braking function, particularly for an electronically controlled pneumatic braking system according to the second aspect of the invention, for vehicles or commercial vehicles, particularly according to the third aspect of the invention, wherein the fail-safe valve unit is preferably configured according to one of the preferred embodiments of the fail-safe valve unit according to the first aspect of the invention described above.

[0053] The method according to the fourth aspect of the present invention includes the following steps:

[0054] - The control unit provides a signal for blocking the fault braking pressure that is effective against fault braking;

[0055] - In the event of a control unit malfunction and / or electrical failure and / or diagnostic condition, the supply of signals is interrupted, thereby automatically terminating the blocking of fault braking pressure to trigger fault braking of the vehicle, wherein,

[0056] - Faulty brake pressure is the parking brake pressure that is regulated by the parking brake function of the braking system to allow air to enter the parking brake cylinder, or the pressure derived from the parking brake pressure.

[0057] Preferably, terminating the blocking of parking brake pressure includes switching the fail-safe valve to the open position. Preferably, a signal is provided to the fail-safe valve to block the fail-safe brake pressure effective for the fail-safe brake. Preferably, the fail-safe valve is monostable and is open when not driven. Preferably, the signal is provided by a control unit. Preferably, the signal is an electrical or electronic signal. In other improvements, it is conceivable that the signal is another signal, such as a pneumatic signal. Preferably, the interruption of signal provision is caused by a malfunction of the control unit and / or a power failure.

[0058] Preferably, the automatic termination of the blocking of the fault brake pressure includes: the fault brake valve automatically switching to its open position. Preferably, the actuation of the fault brake valve is to energize the magnetic part and / or electromagnet of the fault brake valve. Preferably, the fault brake valve is a monostable fault brake valve that opens without current. Preferably, the fault brake pressure is provided to the axle modulator or the service brake cylinder. Preferably, the regulated parking brake pressure is provided by the parking brake module.

[0059] An improved embodiment of the method according to a fourth aspect of the present invention includes a diagnostic process comprising the following steps:

[0060] - Preferably, the fail-safe braking pressure is determined using a pressure sensor at the fail-safe braking interface, wherein...

[0061] Before interrupting the supply of signals, it is preferable to request pressure regulation in the service braking system, preferably a braking request to the axle modulator, in the diagnostic state of the control unit.

[0062] Unlike error conditions and power failures, diagnostic conditions here refer to states specifically introduced by the control unit for diagnostic purposes, wherein, preferably, the state of one or more signals used to block fault braking pressure effective for fault braking corresponds to the state in the event of an error condition and / or power failure. Preferably, in diagnostic conditions, the supply of signals used to block fault braking pressure effective for fault braking is interrupted.

[0063] Preferably, the controlled fault braking pressure is used to verify the correct function of the fault braking valve. Preferably, the correct function of the fault braking valve is achieved by interrupting the control of the fault braking valve, resulting in a pressure response in the form of the controlled fault braking pressure. The reliability of this pressure response can be advantageously verified using a diagnostic process.

[0064] Preferably, the braking request is provided by a braking value transmitter. In particular, the braking request is provided via the vehicle data bus. Preferably, the braking request and / or pressure regulation request in the service braking system appears in the form of an XBR signal or a similar signal of the vehicle data bus.

[0065] Because pressure regulation in the service braking system, particularly the braking request to the axle modulator, is requested before the signal supply is interrupted, potential reliability errors in the braking system, especially in the control unit, are advantageously avoided. Such reliability errors are particularly evident when the fail-safe valve unit introduces pressure into the service braking system without a corresponding braking request—for example, no offset in the brake value transmitter, and especially no offset in the brake pedal. The pressure introduced into the service braking system can be measured, in particular, via the axle modulator pressure sensor.

[0066] Diagnostic procedures can be used to advantageously check or ensure the correct functioning of fail-safe valve units. Diagnostic procedures can be facilitated in different ways. One approach is to perform a diagnostic procedure during vehicle operation in the event of braking triggered by a braking request. This is, for example, when the driver sends an electronic braking request to the axle modulator via a brake value transmitter (or a control unit during autonomous driving).

[0067] In particular, pressure regulation is requested electrically or electronically via a control unit and an electric axle modulator control circuit, especially an electric front axle modulator control circuit or an electric rear axle modulator control circuit. Specifically, braking requests are electric or electronic braking requests.

[0068] In the method according to the fourth aspect of the invention, the advantages of the fail-safe valve unit are advantageously utilized.

[0069] In a fifth aspect for solving the task, the invention also relates to a method for operating a braking system having a fail-safe valve unit for failure braking function, particularly for an electronically controlled pneumatic braking system according to the second aspect of the invention, for vehicles or commercial vehicles, particularly according to the third aspect of the invention, wherein the fail-safe valve unit is preferably configured according to one of the preferred embodiments of the fail-safe valve unit according to the first aspect of the invention described above.

[0070] The method according to the fifth aspect of the present invention includes the following steps:

[0071] - The control unit provides a signal for blocking the fault braking pressure that is effective for fault braking.

[0072] - In the event of a control unit malfunction and / or electrical failure and / or diagnostic condition, the supply of signals is interrupted, thereby automatically terminating the blocking of fault braking pressure for triggering fault braking of the vehicle. This method has a diagnostic procedure comprising the following steps:

[0073] - Preferably, the fault brake pressure is determined using a pressure sensor at the fault brake interface, wherein...

[0074] Before interrupting the supply of signals, it is preferable to request pressure regulation in the service braking system, preferably a braking request to the axle modulator, in the diagnostic state of the control unit.

[0075] Preferably, the fault brake pressure is the parking brake pressure regulated by the parking brake function to allow air to enter the parking brake cylinder, or a pressure derived from the parking brake pressure.

[0076] Preferably, the fail-safe valve unit is pneumatically supplied with brake circuit energy by a brake circuit that performs fail-safe braking independently of the service braking system. "Pneumatic supply" refers to the provision of compressed air, specifically a first pressure, which is provided as the fail-safe braking pressure when at least one fail-safe valve is open.

[0077] Preferably, the fail-safe valve unit is pneumatically supplied with pressure from a pressure accumulator of the brake circuit that performs fail-safe braking, independent of the service braking system. In particular, the fail-safe braking pressure is provided by a pressure accumulator of the parking brake system or another pressure accumulator.

[0078] Preferably, the diagnostic process is performed during service braking of the vehicle's braking system, particularly during existing braking requests. During service braking, a braking request is sent to the axle modulator performing the braking. Such braking requests are particularly electrical or electronic and can be provided by a brake value transmitter or control unit, such as an external control unit and / or an automatic operation control unit. In this case, it is advantageous to provide fault braking pressure because the pressure loading and corresponding increase in pressure measured by the axle modulator pressure sensor are already desired. The effect of fault braking achieved by providing fault braking pressure is advantageously not noticeable or only noticeable to a very small extent during service braking because the requested braking of the vehicle is already in progress.

[0079] In other improvements to this method, the diagnostic process is optionally or additionally performed while the vehicle is stationary, wherein, in particular, a braking request is generated by an external control unit and / or an automatic operation control unit. During the stationary period, the actuation of the service brakes caused by the provision of fault braking pressure goes unnoticed because the vehicle is stationary. However, in this case, it is also advantageous to generate a braking request to avoid reliability errors in the control unit of the braking system.

[0080] The preferred setting is,

[0081] - Braking requests are provided by a braking value transmitter and / or an external control unit and / or an automatic operation control unit. In particular, braking requests are provided via the vehicle data bus. Specifically, braking requests are constituted in the form of CAN signals, especially in the form of XBR signals.

[0082] In the improved version of this method, the following steps are set:

[0083] - To provide signals for individual valves, especially for individual fail-safe valves or individual bistable valves.

[0084] - To obtain the fault braking pressure, especially to verify the reliability of the pressure response for an individual valve. In an improved version, the method may additionally include the step of verifying the reliability of the pressure response for the pressure relief valve.

[0085] Reliability verification includes checking whether the obtained pressure value matches the expected pressure value. This applies to the valve's pressure response, especially the pressure change accompanying the valve's actuation or the expected pressure change. Reliability verification may specifically include checking whether pressure is applied, i.e., whether the pressure is equal to or close to zero, since the valve should be closed (i.e., not inlet) when actuated or when a signal is provided. In this way, diagnostics can be advantageously differentiated because the response of each valve can be checked. Advantageously, all valves are initially left in the unacted state and / or (especially in the case of bistable valves) in their inlet position. In this case, the regulated fail-safe pressure should be measured at the pressure sensor. If this is not the case, an error is output. Subsequently, the individual valves of the fail-safe valve unit can be actuated sequentially to verify the response. For example, switching the fail-safe valve to its blocking position by actuation should result in a decrease in the measured pressure. If this is not the case, an error related to the fail-safe valve can be inferred, which may occur in the valve's mechanical components, the magnet section, or the control circuitry. This single inspection can be performed in a similar manner on the remaining valves, especially additional fault-tolerant valves and / or bistable valves.

[0086] Diagnostic procedures or conditions can be advantageously performed automatically at regular intervals to verify and ensure the functionality of fail-safe valve units, and especially to detect potential errors in fail-safe valve units in advance. For example, diagnostic procedures can be performed each time the vehicle is started, or after a certain number of vehicle starts. In particular, diagnostic procedures can be performed within the scope of a higher level of vehicle self-diagnosis. Specifically, diagnostic procedures can be performed at a service stop after a certain number of service stops, or at service stops at regular intervals (e.g., once daily, weekly, or monthly).

[0087] In the method according to the fifth aspect of the invention, in order to check or ensure the correct functioning of the fail-safe valve unit, a first pressure can advantageously be provided at the main interface of the fail-safe valve unit. This first pressure preferably comes from a separate pressure source, preferably a brake circuit or braking system independent of the brake circuit performing fail-safe braking. For example, for diagnostic procedures, the first pressure at the main interface can be provided by a pressure regulated by the parking brake module, trailer control module, front axle modulator, rear axle modulator, or similar axle modulator.

[0088] In the method according to the fifth aspect of the invention, the advantages of the fail-safe valve unit are advantageously utilized.

[0089] It should be understood that the fail-safe valve unit according to the first aspect of the invention, the electronically controlled pneumatic braking system according to the second aspect of the invention, the vehicle according to the third aspect of the invention, the method according to the fourth aspect of the invention, and the method according to the fifth aspect of the invention have the same and similar sub-aspects, especially those listed in the dependent claims. In this regard, improvements to one aspect of the invention are also referenced to improvements to other aspects of the invention. Attached Figure Description

[0090] Embodiments of the invention will now be described with reference to the accompanying drawings. These drawings are not necessarily to show the embodiments to scale; rather, they are illustrated in a schematic and / or slightly distorted form. Reference is made to relevant prior art to supplement the teachings directly visible from the drawings. It is understood that various modifications and changes can be made to the shape and details of the embodiments without departing from the general spirit of the invention. Features disclosed in the specification and drawings, whether individually or in any combination, can be important for improvements to the invention. Furthermore, all combinations consisting of at least two features disclosed in the specification and / or drawings fall within the scope of the invention. The general spirit of the invention is not limited to the precise shape or details of the preferred embodiments shown and described below, nor is it limited to a subject matter restricted to compared to the claimed subject matter. Values ​​within the stated boundaries within the dimensional ranges described are also disclosed as boundary values ​​and can be used freely and should be protected. For simplicity, the same reference numerals will be used for consistent or similar parts or parts having consistent or similar functions thereafter.

[0091] Further advantages, features, and details of the present invention will become apparent from the following description of preferred embodiments and from the accompanying drawings. Wherein:

[0092] Figure 1 This illustrates a fail-safe valve unit according to the present invention;

[0093] Figure 2A Show in detail Figure 1 The fail-safe valve unit shown;

[0094] Figure 2B , Figure 2C , Figure 2D , Figure 2E Further preferred embodiments of the fail-safe valve unit according to the present invention are shown respectively;

[0095] Figure 3 This invention illustrates an electronically controlled pneumatic braking system with a fail-safe valve unit according to the present invention; and

[0096] Figure 4 The pneumatic wiring diagram of the axle modulator used in an electronically controlled pneumatic braking system is shown. Detailed Implementation

[0097] Figure 1A fail-safe valve unit 1 for an electronically controlled pneumatic braking system 204 according to the present invention is shown. The fail-safe valve unit 1 has a valve main line 30 that pneumatically connects the main interface 20 to the fail-safe interface 22. The fail-safe valve unit 1 has at least one fail-safe valve 40, which can be controlled by the control unit 410 and opened in an open position 40A without being driven, especially without current, such that a first pressure p1 applied to the main interface 20 is provided at the fail-safe interface 22 as a fail-safe braking pressure pN. By providing the fail-safe braking pressure pN at the fail-safe interface 22 in the open position 40A of the fail-safe valve 40, it is advantageous to trigger fail-safe braking BA of the vehicle 200 through the braking system 204, especially the service braking system 510, in the event of an error condition FF, especially an abnormal error FA, and / or an electrical failure FS, in the event of an error condition FF, especially an abnormal error FA, and / or an electrical failure FS in the control unit 410.

[0098] Advantageously, the fail-safe valve unit 1 is arranged in a separate drive control branch 430, such that the first pressure p1 is provided, in particular, by a compressed air reservoir that is different from the compressed air reservoir that supplies the front axle modulator 434 during normal operation.

[0099] Advantageously, the main interface 20 is pneumatically connected to the parking brake system 520. In particular, the main interface 20 is pneumatically connected to the pneumatic parking brake line 496 of the parking brake system 520 to receive the parking brake pressure pFS. Alternatively or additionally, the main interface 20 may be configured to receive a pressure pFS' derived from the parking brake pressure pFS.

[0100] The fail-safe valve unit 1 preferably has an exit valve 50, which is particularly configured as a shuttle valve 52. The exit valve 50 is configured to pneumatically connect the port of the first exit valve port 50.1 and the second exit valve port 50.2, which is subjected to a higher pressure, to a third exit valve port 50.3.

[0101] In particular, in embodiments with selector valve 50, an additional source of compressed air, especially an additional compressed air reservoir 452 or yet another additional compressed air reservoir 450, can be supplied as a second pressure p2 via an additional main port 20'. The selector valve 50 advantageously ensures that the first pressure p1 applied to the main port 20 or the second pressure p2 applied to the additional main port 20' of the parking brake system 520 is transferred to the main valve line 30 depending on which selector valve port 50.1, 50.2 is applied with a higher pressure. Thus, redundancy can be advantageously achieved if compressed air is not supplied at one of the two selector valve ports, for example, due to leakage or system failure.

[0102] The fail-safe braking interface 22 is preferably pneumatically connected to the pneumatic front axle modulator control line 492 via an additional selector valve 56, specifically configured as a shuttle valve 58. The additional selector valve 56 is pneumatically connected at a first additional selector valve interface 56.1 to the brake value transmitter 436 via the pneumatic front axle modulator control line 492. The additional selector valve 56 is pneumatically connected at a second additional selector valve interface 56.2 to at least one fail-safe braking valve 40, specifically fail-safe braking interface 22. The additional selector valve 56 is configured to connect the selector valve interfaces 56.1 and 56.2, to which a higher pressure is applied, to a third selector valve interface 56.3. The third selector valve interface 56.3 is pneumatically connected to the service braking system 510 via the fail-safe braking valve 40 to provide fail-safe braking pressure pN. Specifically, the third selector valve interface 56.3 is pneumatically connected to the front axle modulator 434 of the service braking system 510 via a control interface 434.1. Control interface 434.1 can be formed, in particular, by the redundant interface 618 of the front axle modulator 434. In an embodiment, the third selector valve interface 56.3 can be alternatively or additionally pneumatically connected to the brake cylinder 440 of the service braking system 510. In embodiments without a separate selector valve 56, the fail-safe brake interface 22 is directly connected to the service braking system 510.

[0103] Within the scope of this invention, instead of the front axle modulator 434 or the front axle 210 brake cylinder 440, for drive control purposes, the fail-safe valve unit 1 can still be pneumatically connected to other components of the pneumatic braking system 204, such as the rear axle modulator 438 and / or the parking brake cylinder 442 or a similar service brake chamber 444. The parking brake cylinder 442 is preferably configured as a spring-accumulated brake cylinder. In an alternative embodiment, the braking system 204 and / or control unit 410 may have an additional control unit 420. In particular, the additional control unit 420 may be electrically connected to an additional energy supply unit 426 to supply electrical energy.

[0104] In an optional embodiment, the braking system 204 and / or vehicle 200 may have an external control unit 418, which is connected to one or more valves 40, 60, 70 of the fail-safe valve unit 1, particularly via alternative control lines 412' and 422', in a signal-conducting and / or energy-conducting manner. Specifically, for monitoring control unit 410, the external control unit 418 is connected to control unit 410 via monitoring line 419 in a signal-guided manner. In particular, the external control unit 418 may advantageously be formed by, or be part of, other electronic control units of the vehicle. Such other electronic control units, particularly the external control unit 418, may be, in particular, an automatic operation control unit 464, or an electronic control unit for the steering system, or an electronic control unit for the parking brake system, or an electronic control unit for the air preparation system. The automatic operation control unit 464 may be, in particular, a so-called virtual driver, which generates driving commands based on sensor data, operating data, route data, target data, and similar data and provides these driving commands to the vehicle. Driving commands may include steering commands, acceleration commands, and braking commands, particularly braking requests AB.

[0105] The diagnostic procedure AD for checking the function of fail-safe valve unit 1 can be advantageously performed by the electronic control unit, in particular control unit 410 or external control unit 418, under diagnostic condition FT.

[0106] In all embodiments, the fail-safe valve unit 1 may optionally include a pressure sensor 84, which is particularly disposed on or pneumatically connected to the fail-safe port 22, for measuring the fail-safe pressure pN. The pressure sensor 84 advantageously allows for the verification and / or inspection of the pressure response and thus the function of the fail-safe valve unit 1.

[0107] Figure 2A It shows in detail Figure 1 The fail-safe valve unit 1 is shown. The fail-safe valve unit 1 has a monostable fail-safe valve 40. The fail-safe valve 40 is connected to the control unit 410 via control line 412 in a manner that conducts signals and energy.

[0108] The fail-safe valve 40 is shown in its current undriven and non-current-driven state, in which it is in the open position 40A. In the open position 40A, a pneumatic connection is established between the first valve port 40.1 and the second valve port 40.2 of the fail-safe valve 40. When the fail-safe valve 40 is in the open position 40A, compressed air can flow from the main port 20 to the fail-safe port 22 in the flow direction SR to provide the fail-safe pressure pN.

[0109] By providing a control signal S1 via control line 412, the fail-safe valve 40 can switch from the open position 40A to the blocked position 40B against the resistance of the return spring 41. In the blocked position 40B, a pneumatic connection is established between the first valve port 40.1 and the vent port 40.3. Specifically, during normal operation of the vehicle 200, the fail-safe valve 40 is positioned in its blocked position 40B. Therefore, in this state, there is no pneumatic connection between the main port 20 and the fail-safe port 22 because the pneumatic connection is interrupted at the fail-safe valve 40.

[0110] In the event of an error condition FF, especially when the control signal S1 is missing (and the magnet portion 40.4 of the fault brake valve 40 is therefore without current), the fault brake valve 40 returns to its open position 40A by the reset force generated by the return spring 41.

[0111] Such an error condition FF may occur, for example, when the control unit 410 is not supplied with power due to a power failure FS. In such a power failure, no control signal S1 is transmitted to the fault brake valve 40 accordingly.

[0112] In addition, the error condition FF can also manifest as an abnormal error FA in the control unit 410, and as a measure against the error (especially in the absence of other alternative procedures), the controller 410 switches to a zero signal, and therefore (in order to switch the fault brake valve 40 to the open position 40A) the control signal S1 is intentionally set to 0.

[0113] The diagnostic condition FT can preferably be initiated by the control unit to verify the function of the fail-safe valve unit. The diagnostic condition FT can be initiated within the scope of the diagnostic procedure. In the diagnostic condition FT, the drive control of the fail-safe valve is interrupted in particular by terminating the supply of termination signals S1 and S2.

[0114] Figure 2B Another preferred embodiment of the fail-safe valve unit 1' according to the present invention is shown. (Compared to...) Figure 2A The difference in the embodiment shown is that the fail-safe valve unit 1' shown here has an additional fail-safe valve 60, which is arranged in the valve main line 30 and pneumatically connected in series with the fail-safe valve 40. The additional fail-safe valve 60 is currently configured as a 2 / 2 directional valve 62, and more particularly a 2 / 2 solenoid directional valve 64.

[0115] In other preferred embodiments, the additional fail-safe valve 60 can also be configured as a 3 / 2 directional valve 66, particularly as... Figure 2CThe valve shown is configured as a 3 / 2 solenoid directional valve 68. The additional fail-safe valve 60 is specifically monostable, such that it is in a separate open position 60A when not driven, especially when there is no current. Specifically, the additional fail-safe valve 60 has an additional return spring 61, which moves the additional fail-safe valve 60 to the separate open position 60A when not driven. In the separate open position 60A, the first additional valve port 60.1 of the additional fail-safe valve 60 is pneumatically connected to the second additional valve port 60.2 of the additional fail-safe valve 60. Specifically, the additional fail-safe valve 60 is driven by a separate control signal S2, specifically by a control unit 410 or a separate control unit 420, via a separate control line 422.

[0116] The implementation with an additional fault valve 60 is particularly advantageous in the optional braking system 204, which has an additional control unit 420 or similar redundant control device. In such a braking system 204, in particular, control unit 410 is assigned to the main system B1, while the additional control unit 420 is assigned to the first backup level B2. In the event of an error condition FF in the main system B1, particularly in control unit 410, the failsafe valve unit 1' can therefore continue to be driven via the still functional backup level B2, in particular, the supply of the fault braking pressure pN is blocked by continuously driving the additional fault brake valve 60 to another blocking position 60B. The modulation of the fault braking pressure pN is particularly possible by means of the additional fault brake valve 60, which is configured as a 2 / 2 solenoid directional valve 64. Thus, even in the event of a partial failure, especially when the main system B1 fails, it is advantageous to achieve graded braking, particularly via the redundant interface 618, and braking functionality is ensured via a separate drive control branch through the failsafe valve unit 1.

[0117] In the case of a double error FD, that is, when there is an error condition FF, especially in the form of an abnormal error FA and / or a power failure FS, in both control unit 410 and another control unit 420, the fault brake valve 40 and the other fault brake valve 60 are in their open positions 40A and 60A, respectively, due to their monostable characteristics, so as to provide fault brake pressure pN at the fault brake interface 22.

[0118] Figure 2C Another preferred embodiment of the fail-safe valve unit 1 is shown. (Compared to...) Figure 2BThe difference in the illustrated embodiment is that, currently, the additional fail-safe valve 60 is configured as a 3 / 2 directional control valve 66, particularly as a 3 / 2 solenoid directional control valve 68. Specifically, the fail-safe valve 40 and the additional fail-safe valve 60 are advantageously constructed identically. In particular, the additional fail-safe valve 60, configured as a 3 / 2 directional control valve 66, has an additional vent port 60.3, which, in the blocked position 60B, is connected to the first additional valve port 60.1. When the additional fail-safe valve 60 is switched to its blocked position 60B, the fail-safe port 22 can be advantageously vented via this additional vent port 60.3.

[0119] Advantageously, in all implementations, such as Figure 2C As shown, a pressure relief valve 34 may be present in the main valve line 30. With the help of the pressure relief valve 34, a pre-defined air pressure can be adjusted to provide a fault braking pressure pN at the fault braking interface 22, so as to achieve a suitable braking effect for the vehicle during fault braking.

[0120] In the implementation, the additional fail-safe valve 60 is also driven jointly with fail-safe valve 40 via control signal S1. Specifically, the additional fail-safe valve 60 is driven jointly with fail-safe valve 40 via control line 412, and is driven jointly with fail-safe valve 40 by control unit 410. The multiple arrangement of fail-safe valves 40 and 60, especially the arrangement with fail-safe valve 40 and the additional fail-safe valve 60, has the advantage of redundancy in the event of valve failure, particularly mechanical or electrical failure, in one of the fail-safe valves 40 or 60. For example, if one of the fail-safe valves 40 or 60 can no longer be driven and moves from the open position 40A or 60A to the blocked position 40B or 60B due to jamming or a defective magnetic part, the vehicle will unintentionally be in a fail-safe braking (BA) state caused by fail-safe valve unit 1". This unintentional state can be eliminated and / or prevented by the other still-functioning fail-safe valve unit.

[0121] Figure 2D Another preferred embodiment of the fail-safe valve unit 1"' with a bistable valve 72 is shown. Advantageously, in all embodiments, such as Figure 2C The bistable valve 72 shown is arranged in the valve main line 30.

[0122] The bistable valve 72 is connected to the control unit, particularly the control unit 410 or another control unit 420, or yet another control unit not shown herein, via a separate control line 460 in a signal and / or energy conduction manner, and can be controlled via a third control signal S3. The bistable valve 72 is characterized in that it is not directly affected by the erroneous condition FF because it remains unchanged in the previously switched position due to its bistable characteristics.

[0123] In contrast, the fault brake valve 40 and the other fault brake valve 60, due to their monostable characteristics, are characterized by returning to their current open positions 40A and 60A, respectively, when no current is applied. In this way, according to the invention, even when no control signals S1 and S2 are applied to the fault brake valve 40, and especially the other fault brake valve 60, or when control signals S1 and S2 are applied as zero signals, the fault brake valves 40 and 60 can automatically switch to their open positions 40A and 60A. This situation of no control signals S1 and S2 or zero signals occurs particularly when an abnormal error FA or electrical fault FS occurs in the control units 410 and 420.

[0124] This is particularly relevant to the automatic, especially autonomous, operation of the vehicle 200 when the bistable valve 72 is in its second position 72B. This is because, in this case, a pneumatic connection is established between the first and second bistable valve interfaces 72.1, 72.2, and in this manner (when the fail-safe valves 40, 60 return to their open positions 40A, 60A), a fail-safe braking pressure pN is provided at the fail-safe braking interface 22 to brake the vehicle 200. In automatic, especially autonomous, operation, the vehicle 200 can be controlled, for example, by an automatic operation control unit 464, which is connected to the vehicle data bus 462 via a conductive signal.

[0125] This situation is particularly relevant to manual operation of vehicle 200 when bistable valve 72 is in its first position 72A. In this case, failure braking is prevented from being performed in fault condition FF, especially in the case of double fault FD, by providing failure braking pressure pN at failure braking interface 22 via the main valve circuit 30.

[0126] Figure 2E Another preferred embodiment of the fail-safe valve unit 1 with pressure sensor 84 is shown. Currently, pressure sensor 84 is arranged at fail-safe port 22 and configured to measure the supplied fail-safe pressure pN. With the aid of pressure sensor 84, the rationality of pressure response and / or function of fail-safe valve unit 1 can be advantageously verified and / or checked.

[0127] In all embodiments, a fault relay valve 80 may also be provided. The fault relay valve 80 has a fault control interface 80.1, a fault reserve interface 80.2, a fault operating interface 80.3, and a fault venting interface 80.4. The fault reserve interface 80.2 is pneumatically connected to the main interface 20. The fault control interface 80.1 is connected to the valve main line 30, such that the valve main line, including all fault brake valves 40, 60, and possibly bistable valves 72, forms the control line for the fault relay valve 80. The fault operating interface 80.3 is pneumatically connected to the fault brake interface 22. The fault relay valve 80 enhances the air volume, thus advantageously reducing the air volume switched by the fault brake valves and possibly bistable valves, and thus allowing these valves to be sized smaller and / or required less.

[0128] Figure 3 An electronically controlled pneumatic braking system 204 according to the invention is shown, comprising a fail-safe valve unit 1 for a fail-safe braking function FN. Currently, the electronically controlled pneumatic braking system 204 is used in a vehicle 200 configured as a commercial vehicle 202, which is shown schematically herein, particularly having the front axle 210 and the rear axle 220 shown.

[0129] The electronically controlled pneumatic braking system 204 is controlled by a control unit 410. The control unit 410 is connected to the energy supply unit 416 via a supply line 414 to guide energy. The control unit 410 is electrically connected to the brake value transmitter 436 via a brake value transmitter control line 484 to receive brake signals. The control unit 410 is also configured to drive the front axle modulator 434 via the front axle modulator control line 486, which transmits signals electrically, depending on the brake signal or the possible driving sequence of the automatic operation control unit 464 during automatic driving. In particular, an electric or electronic braking request AB to the axle modulator 432 can trigger braking via the front axle modulator control line 486. The electronic braking request AB can be formed, in particular, by CAN commands and / or XBR commands. The front axle modulator 434 is configured to supply compressed air, via a separate compressed air reservoir 452, to the pneumatic front axle brake circuit 512 of the electronically controlled pneumatic braking system 204's service brake system 510, thereby actuating at least one service brake cylinder 440 associated with the front wheel 212 to perform service braking BB. The control unit 410 is also configured to actuate the service brake chamber 444 of at least one parking brake cylinder 442 associated with the rear wheel 222 via a pneumatic rear axle brake circuit 514 through pneumatic actuation. The control unit 410 is electrically connected to the rear axle modulator 438 via a rear axle modulator control line 488 in the form of a guide signal. Here, the compressed air for the pneumatic rear axle brake circuit 514 is supplied by yet another compressed air reservoir 450 and, under the actuation of the control unit 410, is transmitted to the service brake chamber 444 via the rear axle modulator 438. Therefore, the control unit 410 is configured to brake the front wheels 212 and the rear wheels 222 of the vehicle 204. The front axle modulator control line 486 and / or the rear axle modulator control line 488 are specifically configured as vehicle data bus lines, particularly CAN lines.

[0130] Braking system 204 has a parking brake function FFS with parking brake module 480. The parking brake function FFS is preferably implemented by means of parking brake system 520 and / or parking brake module 480. Through the parking brake function FFS, a parking brake pressure pFS for inlet air to the parking brake cylinder 442 can be regulated. Therefore, the parking brake function FFS preferably includes parking brake module 480. The parking brake module 480 of braking system 204 is configured to actuate the parking brake chamber 446 of one of the two parking brake cylinders 442 respectively associated with the rear wheel 222 via the pneumatic rear axle brake circuit 522 of parking brake system 520, particularly via the pneumatic parking brake line 496, by means of the regulated parking brake pressure pFS. The parking brake module 480 is electrically connected to the parking brake operating element 482 by means of a guide signal. Therefore, the pneumatic rear axle brake circuit 522 of the parking brake system 520 can be activated and deactivated via the parking brake operating element 482. The parking brake module 480 is pneumatically connected to the compressed air reservoir 454 via the reservoir line 448 to supply compressed air.

[0131] The rear axle modulator 438 is connected to the control unit 410 via the rear axle modulator control line 488 in a signal-guided manner. Compressed air for the parking brake system 520 is supplied here by the compressed air reservoir 454.

[0132] Braking value transmitter 436 is pneumatically connected to the pneumatic control interface 434.1, and in particular the redundant interface 618, of the front axle modulator 434 via pneumatic front axle modulator control line 492, in order to drive the pneumatic front axle braking circuit 512. Specifically, the front axle modulator 434 is configured to regulate braking pressure to the service brake cylinder 440 when pneumatic pressure is applied via the front axle modulator control line 492. Braking value transmitter 436 is pneumatically connected to the rear axle modulator 438 via pneumatic rear axle modulator control line 494 (in a similar manner to the front axle modulator 434), in order to drive the pneumatic rear axle braking circuit 514. Specifically, the rear axle modulator 438 is configured to regulate braking pressure to the service brake chamber 444 when pneumatic pressure is applied via the pneumatic rear axle modulator control line 494. In particular, the front axle modulator 434 and / or the rear axle modulator 438 have a relay valve 602 for regulating the braking pressure.

[0133] The main interface 20 of the fail-safe valve unit 1 is pneumatically connected to the pneumatic rear axle brake circuit 522 of the parking brake module 480 and the parking brake system 520 via a pneumatic parking brake line 496. An additional selector valve 56 is advantageously arranged in the pneumatic front axle modulator control line 492 for pneumatically connecting the fail-safe valve interface 22 to the control input of the front axle modulator 434.

[0134] The fail-safe valve 40 is connected to the control unit 410 via control line 412 in a manner that guides signals and energy. The vehicle 200 may have an additional pressure regulating device 489, in the form of a trailer control module 490, for pneumatic supply to a trailer of the vehicle 200, which is not shown here.

[0135] When a fail-safe braking pressure pN is provided at fail-safe braking interface 22, the fail-safe braking pressure pN reaches the front axle modulator 434, which pneumatically actuates two service brake cylinders 440 respectively associated with the front axle 210. Therefore, by applying the fail-safe braking pressure pN to the front axle modulator 434 to actuate the service brake cylinders 440, fail-safe braking BA of the front axle 210 and thus the vehicle 200 is achieved. The fail-safe valve unit 1 is arranged in a separate drive control branch 430 of the electronically controlled pneumatic braking system 204, which is provided independently of the conventional drive control of the service brake cylinders 440, particularly via the brake value transmitter 436. Nevertheless, within the scope of the invention, it is also possible to directly provide the fail-safe braking pressure pN to at least one service brake cylinder 440, or to other brake cylinders, for example, to the service brake chamber 444 of the parking brake cylinder 442 associated with the rear wheel 222. In particular, the compressed air reservoir 454 that supplies compressed air to the parking brake module 480 is separate from the additional compressed air reservoir 452 that stores compressed air for the service brake cylinder 440 during normal operation, in order to improve the independence of the fail-safe valve unit 1 and thereby advantageously provide redundant fail-safe braking functionality.

[0136] Figure 4The pneumatic wiring diagram of the axle modulator 432, and particularly the front axle modulator 434, is shown. The axle modulator 432 has a relay valve 602, which can be loaded with control pressure via control line 604 and valve control interface 602.1 to regulate the working pressure at the working interface 602.3. Compressed air, particularly from an additional compressed air reservoir 452, is supplied to the relay valve 602 via a reserve interface 602.3. The working interface 602.3 is pneumatically connected, particularly via working line 606, to the service brake cylinder 440 of the front axle 210. The control line 604 has an electrically driven control branch 614 with a first drive control valve 620 and a second drive control valve 622, which is configured to allow air intake and / or venting at the valve control interface 602.1. In particular, the electric drive control branch 614, with drive control valves 620 and 622, can be controlled via control unit 410 and / or main system B1, especially via front axle modulator control line 486. Control line 604 has a pneumatic drive control branch 616 with a backup valve 630. Valve control interface 602.1 is pneumatically connected to control interface 434.1 via pneumatic drive control branch 616. Control interface 434.1 is configured as a redundant interface 618 for front axle modulator 434. Backup valve 630 is configured as a 2 / 2 directional valve and is monostable and normally open, so as to open in the absence of drive control in case of fault condition FF, and can be pneumatically driven via pneumatic drive branch 616. Drive control valves 620 and 622 of electric drive control branch 614 are correspondingly configured as 2 / 2 directional valves and are monostable and normally closed. The axle modulator 432 has an axle modulator pressure sensor 82, which is arranged in the working line 606 for measuring the working pressure pA.

[0137] Advantageously, the front axle modulator 434 has a throttling element 610, particularly a nozzle orifice 612, which pneumatically connects the operating line 606 to the control line 604. The throttling element 610 has a reduced nominal size compared to the control line 604 and / or the operating line 606.

[0138] Throttling element 610 is particularly arranged in the relay piston of relay valve 602, especially as nozzle orifice 612 in the relay piston. With the aid of the throttling element, it is advantageously ensured that the parking brake is automatically deflated (independent of any backflow function and / or leakage or pressure loss that may exist in the front axle brake circuit), and thus the safe state of the vehicle can be permanently ensured by the vehicle being stationary. With this throttling element, even in the event of leakage in the working line 606 or the portion pneumatically connected to the working line 606, the engagement of parking brake cylinder 442 can be advantageously ensured. With this throttling element, a pneumatic connection is established between the portion of the axle modulator 432 that guides the working pressure, especially the portion of the working line 606 and the portion of the axle modulator 432 that guides the control pressure, especially the control line 604. Therefore, leakage occurring in the portion 605 that guides the working pressure pA also results in a pressure drop in the portion 603 that guides the control pressure pS, and in this case, the engagement of the parking brake is caused by the pneumatic connection of the portion of the control pressure to the fail-safe valve unit according to the invention. In particular, the throttling element is located in the relay piston of the relay valve 602 of the axle modulator 432.

[0139] The description given herein for the front axle modulator 434 can be applied in the same manner to other axle modulators 432, such as the rear axle modulator 438, in other embodiments.

[0140] List of reference numerals (part of the instruction manual)

[0141] 1, 1', 1", 1", 1", 1", Fail-safe valve unit

[0142] 20 Main Interface

[0143] 22 Failure Braking Interface

[0144] 30 Valve Main Circuit

[0145] 34 Pressure relief valve

[0146] 40 Monostable Failure Braking Valve

[0147] 40.1 First valve port of the fault brake valve

[0148] 40.2 Second valve interface of the fault brake valve

[0149] 40.3 Bleeding port of the fault brake valve

[0150] 40.4 First magnet section, magnet section of fault brake valve

[0151] 40A Fault Brake Valve Opening Position, Opening Position

[0152] 40B Fault Braking Valve: Blocking Position, Blocking Position

[0153] 41. Return spring, return spring of fault brake valve

[0154] 50 Select valve

[0155] 50.1 Select the first interface of the valve

[0156] 50.2 Select the second port of the valve

[0157] 50.3 Select the third port of the valve

[0158] 52 Shuttle valve, height-selective shuttle valve

[0159] 56. Other selector valves

[0160] 56.1 The first interface of the alternative selector valve

[0161] 56.2 The second interface of the additional selector valve

[0162] 56.3 The third interface of the additional selector valve

[0163] 58. Other shuttle valves, other height-selective shuttle valves

[0164] 60. Other monostable failure braking valves

[0165] 60.1 The first valve interface of the other faulty brake valve

[0166] 60.2 Second valve interface of the other faulty brake valve

[0167] 60.3 Other faulty brake valve venting ports

[0168] 60.4 Other magnet components, magnet components of other faulty brake valves

[0169] 60A Other faulty brake valve opening position, other opening position

[0170] 60B Other faulty brake valve blocking positions, other blocking positions

[0171] 61. Additional return springs, and return springs for additional faulty brake valves.

[0172] 70 Bistable Valve Unit

[0173] 72 Bistable Valve

[0174] 72.1 First Bistable Valve Interface

[0175] 72.2 Second Bistable Valve Interface

[0176] 72.3 Venting section of a bistable valve

[0177] 72A bistable valve first position

[0178] 72B Bistable Valve, Second Position

[0179] 80 Fault relay valve

[0180] 80.1 Fault Control Interface

[0181] 80.2 Fault Reserve Interface

[0182] 80.3 Fault Handling Interface

[0183] 80.4 Fault venting port

[0184] 82 Axle modulator pressure sensor

[0185] 84 Pressure Sensor

[0186] 200 vehicles

[0187] 202 Commercial Vehicles

[0188] 204 Braking system, electronically controlled pneumatic braking system

[0189] 210 Front Axle

[0190] 220 rear axle

[0191] 410 Control Unit

[0192] 412 Control Circuit

[0193] 412' Alternate control circuit

[0194] 414 Supply Line

[0195] 416 Energy Supply Department

[0196] 418 External Control Unit

[0197] 419 Surveillance Line

[0198] 420 Other control units

[0199] 422 Other control circuits

[0200] 422' Alternative control circuit

[0201] 426 Other Energy Supply Department

[0202] 430 Separate drive and control circuit

[0203] 432 Axle Modulator

[0204] 434 Front Axle Modulator

[0205] 436 Braking Value Transmitter

[0206] 438 Rear Axle Modulator

[0207] 440 service brake cylinder

[0208] 442 Parking brake cylinder

[0209] 444 Parking brake cylinder service brake chamber

[0210] 446 Parking brake chamber of parking brake cylinder

[0211] 448 Reserve circuit, parking brake system reserve circuit

[0212] 450 Another compressed air reservoir

[0213] 452 Additional compressed air reservoir

[0214] 454 Compressed Air Reserve

[0215] 460 Another control line, vehicle data bus line

[0216] 462 Vehicle Data Bus

[0217] 464 Automatic Operation Control Unit

[0218] 480 Parking Brake Module

[0219] 482 Parking Brake Operating Unit

[0220] 484 Electrical braking value transmitter control circuit

[0221] 486 Electric Front Axle Modulator Control Circuit

[0222] 488 Electric Rear Axle Modulator Control Circuit

[0223] 489 Pressure regulating device

[0224] 490 Trailer Control Module

[0225] 492 Pneumatic front axle modulator control circuit

[0226] 494 Pneumatic rear axle modulator control circuit

[0227] 496 Pneumatic parking brake circuit

[0228] 510 Service Braking System

[0229] 512 Pneumatic front axle brake circuit of the service braking system

[0230] 514 Pneumatic rear axle brake circuit of the service braking system

[0231] 516 Redundant circuits in the service braking system

[0232] 520 Parking Brake System

[0233] 522 Pneumatic rear axle brake circuit of parking brake system

[0234] 524 Bypass supply branch for parking brake system

[0235] 602 Relay Valve

[0236] 602.1 Relay Valve Control Interface

[0237] 602.2 Relay Valve Backup Interface

[0238] 602.3 Relay Valve Working Interface

[0239] 603 Section for guiding and controlling pressure

[0240] 604 Control Circuit

[0241] 605 The section on managing work pressure

[0242] 606 working line

[0243] 610 Throttling component

[0244] 612 Nozzle orifice

[0245] 614 Electric drive and control branch

[0246] 616 Pneumatic drive and control circuit

[0247] 618 Redundant Interfaces

[0248] 620 First drive control valve

[0249] 622 Second drive control valve

[0250] 630 Backup Valve

[0251] AB braking request

[0252] AD Diagnostic Process

[0253] B1 Main System

[0254] B2 First Reserve Tier

[0255] BA (Brake in Action)

[0256] BB service brake

[0257] FA exception error

[0258] FD double error

[0259] FF Error Status

[0260] FFS parking brake function

[0261] FN (Fail-safe Braking) function

[0262] FS power failure

[0263] FT diagnostic status

[0264] p1 First pressure

[0265] p2 Second pressure

[0266] pA work pressure

[0267] pB ultimate pressure

[0268] pE Adjustment Pressure

[0269] pFS Parking brake pressure

[0270] pFS' is the pressure derived from the parking brake pressure.

[0271] pN fault braking pressure

[0272] pS control pressure

[0273] pWV additional reserve pressure

[0274] S1 First Control Signal

[0275] S2 Second Control Signal

[0276] S3 Third Control Signal

[0277] SR flow direction

Claims

1. A fail-safe valve unit (1) for the fail-safe function (FN) of an electronically controlled pneumatic braking system (204) for a vehicle (200), wherein, The braking system (204) has at least one control unit (410), and the fail-safe valve unit (1) has: - Provides the main interface (20) for the first pressure (p1) and the fault braking interface (22), - A fault-stop valve (40) configured as a monostable valve, the fault-stop valve being controllable by the control unit (410) or an external control unit (418) and configured as such. - In the open position (40A), the main interface (20) and the fail-safe interface (22) are pneumatically connected to regulate the fail-safe pressure (pN) at the fail-safe interface (22). Its features are, - In the fault condition (FF) and / or power failure (FS) and / or diagnostic condition (FT) of the control unit (410), the fault brake valve (40) is in the open position (40A), and - Failure braking (BA) on the vehicle (200) is triggered via the braking system (204) by providing the failure braking pressure (pN) at the failure braking interface (22), wherein, - The main interface (20) is pneumatically connected to the parking brake function (FFS) to receive the regulated parking brake pressure (pFS) as the first pressure (p1).

2. The fail-safe valve unit (1) according to claim 1, characterized in that, - The fail-safe valve unit (1) has a selector valve (50) having a first port (50.1) pneumatically connected to the parking brake function (FFS) for receiving the first pressure (p1). - It has a second interface (50.2) that is pneumatically connected to another compressed air reservoir (450, 452) for receiving an additional reserve pressure (pWV) as a second pressure (p2), and - It has a third interface (50.3), which is pneumatically connected to the fault brake valve (40), wherein, - The selector valve (50) is configured to pneumatically connect the port in the first and second ports (50.1, 50.2) where a higher pressure (p1, p2) is applied to the third port (50.3).

3. The fail-safe valve unit (1) according to claim 1 or 2, characterized in that, - The failure braking pressure (pN) is provided as a control pressure (pS) to the axle modulators (432, 434, 438), or - The fault braking pressure (pN) is provided as braking pressure (pA) to the brake cylinder (440).

4. The fail-safe valve unit (1) according to claim 1 or 2, characterized in that... have - An additional fault brake valve (60), which is pneumatically connected in series with the fault brake valve (40) and can be controlled by control units (410, 420), and - The additional fail-safe valve (60) is opened in the open position (60A) when not driven, so that the first pressure (p1) applied at the main interface (20) is provided at the fail-safe interface (22) as the fail-safe pressure (pN).

5. The fail-safe valve unit (1) according to claim 4, characterized in that, - The additional fault brake valve (60) is configured as a 2 / 2 directional valve (62).

6. The fail-safe valve unit (1) according to claim 1 or 2, characterized in that, - The fault brake valve (40) is configured as a 3 / 2 directional valve (42, 66).

7. The fail-safe valve unit (1) according to claim 4, characterized in that, - The additional fault brake valve (60) is configured as a 3 / 2 directional valve (42, 66).

8. The fail-safe valve unit (1) according to claim 1 or 2, characterized in that... It has a pressure relief valve (34).

9. The fail-safe valve unit (1) according to claim 1 or 2, characterized in that... have - A bistable valve (72) configured to switch between a first deactivated position (72A) connected to the main circuit of the valve (30) or to the vent (72.3) and a second activated position (72B) connected to the main circuit of the valve (30), wherein the bistable valve (72) is pneumatically connected in series with at least one fault brake valve (40, 60).

10. The fail-safe valve unit (1) according to claim 1 or 2, characterized in that... have - An additional selector valve (56) having: a first additional port (56.1) pneumatically connected to a brake value transmitter (436) for receiving brake value transmitter pressure (pGB), - A second additional interface (56.2), which is pneumatically connected to the fail-safe interface (22), is used to receive the fail-safe pressure (pN), and - A third additional interface (56.3), said third additional interface being pneumatically connected to the service brake cylinder (440) or the axle modulator (432), wherein, - The additional selector valve (56) is configured to pneumatically connect the port in the first and second additional ports (56.1, 56.2) where a higher pressure (pGB, pN) is applied to the third additional port (56.3).

11. The fail-safe valve unit (1) according to claim 1, characterized in that, The vehicle in question is a commercial vehicle (202).

12. The fail-safe valve unit (1) according to claim 4, characterized in that, The additional fault brake valve (60) can be controlled by an additional control unit (420) or an external control unit (418).

13. The fail-safe valve unit (1) according to claim 4, characterized in that, The additional fail-safe valve (60) is opened in the open position (60A) in the absence of current, so that the first pressure (p1) applied at the main interface (20) is provided at the fail-safe interface (22) as the fail-safe pressure (pN).

14. The fail-safe valve unit (1) according to claim 5, characterized in that, - The additional fault brake valve (60) is configured as a 2 / 2 solenoid directional valve (64).

15. The fail-safe valve unit (1) according to claim 6, characterized in that, - The fault brake valve (40) is configured as a 3 / 2 solenoid directional valve (44, 68).

16. The fail-safe valve unit (1) according to claim 7, characterized in that, - The additional fault brake valve (60) is configured as a 3 / 2 solenoid directional valve (44, 68).

17. The fail-safe valve unit (1) according to claim 10, characterized in that, The first additional interface is pneumatically connected to the pneumatic front axle modulator control line (492) for receiving brake value transmitter pressure (pGB).

18. An electronically controllable pneumatic braking system (204) for a vehicle (200), the electronically controllable pneumatic braking system having a control unit (410), Its features have -The fail-safe valve unit (1) according to any one of the preceding claims, wherein, - The fail-safe valve unit (1) is arranged in a separate drive / control branch (430), and - Via fail-safe interface (22) it can be pneumatically connected to at least one service brake cylinder (440) and / or service brake chamber (444) and / or axle modulator (434, 438) for providing fail-safe braking pressure (pN) to the axle modulator (434) to trigger fail-safe braking (BA) on the vehicle (200).

19. The electronically controllable pneumatic braking system (204) according to claim 18, characterized in that... have - Axle modulators (434, 438) having a throttling element (610) that pneumatically connects a portion (603) of the guide control pressure (pS) of the axle modulator (434) to a portion (605) of the guide working pressure (pA) of the axle modulator (434).

20. The electronically controllable pneumatic braking system (204) according to claim 18 or 19, characterized in that, - The control unit (410) is associated with the main system (B1) of the electronically controlled pneumatic braking system (204), and the electronically controlled pneumatic braking system (204) further comprises: - An additional control unit (420) for the first backup level (B2), wherein, The fault brake valve (40) can be driven by the control unit (410), and the other fault brake valve (60) can be driven by the other control unit (420). The first control unit (410) and the second control unit (420) can be supplied with energy independently of each other and / or can at least partially substitute for each other in terms of their functions.

21. The electronically controllable pneumatic braking system (204) according to claim 18, characterized in that, The vehicle in question is a commercial vehicle (202).

22. The electronically controllable pneumatic braking system (204) according to claim 19, characterized in that, The throttling element is a nozzle orifice (612).

23. A vehicle (200) having a braking system (204) according to any one of claims 18 to 22.

24. A method for operating a braking system (204) having a fail-safe valve unit (1), the fail-safe valve unit being used for fail-safe braking (FN) of an electronically controllable pneumatic braking system (204) for use in a vehicle (200) or a commercial vehicle (202), Its features It includes the following steps: -Signals (S1, S2) for blocking the fault braking pressure (pN) effective against fault braking (BA) are provided by control units (410, 420) or external control units (418); - In the event of an error condition (FF) and / or electrical failure (FS) and / or diagnostic condition (FT) of the control units (410, 420), the supply of the signals (S1, S2) is interrupted, thereby automatically terminating the blocking of the fault braking pressure (pN) for triggering fault braking (BA) of the vehicle (200), wherein, - The fault brake pressure (pN) is the parking brake pressure (pFS) regulated by the parking brake function (FFS) to allow air to enter the parking brake cylinder (442).

25. The method according to claim 24, characterized in that... The diagnostic process (AD) includes the following steps: -The fault braking pressure (pN) is obtained at the fault braking interface (22), wherein, - Before interrupting the supply of the signals (S1, S2), a request is made for pressure regulation in the service braking system (510).

26. The method according to claim 24, characterized in that, The failsafe valve unit (1) is a failsafe valve unit (1) according to any one of claims 1 to 17.

27. The method according to claim 24, characterized in that, The electronically controlled pneumatic braking system (204) is an electronically controlled pneumatic braking system according to any one of claims 18 to 22.

28. The method according to claim 24, characterized in that, The vehicle (200) is the vehicle according to claim 23.

29. The method according to claim 25, characterized in that, The fault braking pressure (pN) is determined at the fault braking interface (22) by means of a pressure sensor (84).

30. The method according to claim 25, characterized in that, Before interrupting the supply of the signals (S1, S2), a braking request (AB) is requested for the axle modulator (432).

31. A method for operating a braking system (204) having a fail-safe valve unit (1), the fail-safe valve unit being used for fail-safe braking (FN) of an electronically controllable pneumatic braking system (204) for use in a vehicle (200) or a commercial vehicle (202), Its features It includes the following steps: - Signals (S1, S2) for blocking the fault braking pressure (pN) effective against fault braking (BA) are provided via control units (410, 420) or external control units (418). - In the event of an error condition (FF) and / or electrical failure (FS) and / or diagnostic condition (FT) of the control unit (410, 420), the supply of the signals (S1, S2) is interrupted, thereby automatically terminating the blocking of the fault braking pressure (pN) for triggering fault braking (BA) of the vehicle (200). The method has a diagnostic procedure (AD) comprising the following steps: - The fault braking pressure (pN) is obtained at the fault braking interface (22), wherein, - Before interrupting the supply of the signals (S1, S2), a request is made to perform pressure regulation in the service braking system (510).

32. The method according to claim 31, characterized in that, - The failsafe valve unit (1) is pneumatically supplied by a brake circuit (514, 522) that performs the failsafe braking (BA) independently of the service brake system (510).

33. The method according to claim 31 or 32, characterized in that, - The failsafe valve unit (1) is pneumatically supplied by pressure accumulators (450, 452) of the pressure accumulator (454) of the brake circuit (512) that performs the fail brake (BA) independently of the service brake system (510).

34. The method according to claim 31 or 32, characterized in that, - The diagnostic procedure (AD) is performed during the service braking (BB) of the service braking system (510), or The diagnostic procedure (AD) is performed while the vehicle (200) is stationary.

35. The method according to claim 31 or 32, characterized in that, - Braking requests (AB) are provided by a braking value transmitter (436) and / or an external control unit (418) and / or an automatic operation control unit (464).

36. The method according to claim 31 or 32, characterized in that... It includes the following steps: - Provide signals (S1, S2, S3) for individual valves (40, 60, 70, 72). - Obtain the fault braking pressure (pN).

37. The method according to claim 31, characterized in that, The failsafe valve unit (1) is a failsafe valve unit (1) according to any one of claims 1 to 17.

38. The method according to claim 31, characterized in that, The electronically controlled pneumatic braking system (204) is an electronically controlled pneumatic braking system according to any one of claims 18 to 22.

39. The method according to claim 31, characterized in that, The vehicle (200) is the vehicle according to claim 23.

40. The method according to claim 31, characterized in that, The fault braking pressure (pN) is determined at the fault braking interface (22) by means of a pressure sensor (84).

41. The method according to claim 31, characterized in that, Before interrupting the supply of the signals (S1, S2), a braking request (AB) is requested for the axle modulator (432).

42. The method according to claim 34, characterized in that, The diagnostic procedure (AD) is performed during the current braking request (AB).

43. The method according to claim 34, characterized in that, The diagnostic process (AD) is performed while the vehicle (200) is stationary, wherein a braking request (AB) is generated.

44. The method according to claim 34, characterized in that, The diagnostic process (AD) is performed while the vehicle (200) is stationary, wherein a braking request (AB) is generated by an external control unit (418) and / or an automatic operation control unit (464).

45. The method according to claim 35, characterized in that, The braking request (AB) is provided via the vehicle data bus (462), and / or the braking request (AB) is constituted in the form of a CAN signal.

46. ​​The method according to claim 45, characterized in that, The braking request (AB) is constituted in the form of an XBR signal.

47. The method according to claim 36, characterized in that... The procedure includes the following steps: providing signals (S1, S2, S3) to a single fault brake valve (40, 60) or a single bistable valve (72).

48. The method according to claim 36, characterized in that... The procedure includes the following steps: verifying the reliability of the pressure response for the individual valves (40, 60, 70).

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