Vehicle brake system

Abstract

To provide a vehicle brake system that includes a brake pedal and a first actuation module.SOLUTION: The first actuation module includes a master cylinder, a pedal feel simulator, a primary pedal sensor, a first pressure supplier, a first controller, and a first actuation module port. The system includes a second actuation module having a second pressure supplier, a second controller, and a second actuation module port. The vehicle braking system includes a modulation module having first and second ports coupled, respectively, to the first and second actuation module ports, a second pedal sensor, a pump, a third controller, and ports coupled to the wheel cylinders. In a redundant back-up mode of operation, the brake request is configured to be met by operation of the pump of the modulation module according to the second pedal sensor and the algorithm of the third controller.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to co-pending U.S. Provisional Patent Application No. 63 / 642,274, filed May 3, 2024, the entire contents of which are incorporated herein by reference.

[0002] Field DETAILED DESCRIPTION OF THE INVENTION The embodiments, examples and aspects described herein relate, inter alia, to systems and methods for implementing hydraulic braking in a vehicle.

[0003] overview In one aspect, the present disclosure provides a vehicle braking system including a brake pedal configured to receive a braking request for operation by a driver and a first actuation module, the first actuation module including: a master cylinder coupled to the brake pedal to displace fluid in response to the braking request from the driver; a pedal feel simulator coupled to the master cylinder and configured to provide tactile feedback to the brake pedal in response to the braking request; a primary pedal sensor; a first isolated electro-hydraulic pressure supplier operable to displace fluid; a first controller programmed with an algorithm configured to receive a signal from the primary pedal sensor and to output a signal to the first isolated electro-hydraulic pressure supplier to control an output of the first isolated electro-hydraulic pressure supplier to a first brake circuit terminating at a first pair of wheel cylinders; and a first actuation module port. The vehicle braking system includes a second actuation module including a second separate electro-hydraulic pressure supplier operable to displace fluid, a second controller programmed with an algorithm for receiving signals from the first controller and for outputting signals to the second separate electro-hydraulic pressure supplier to control the output of the second separate electro-hydraulic pressure supplier to a second brake circuit terminating in a second pair of wheel cylinders, and a second actuation module port. The vehicle braking system includes a modulation module including a first port and a second port coupled to the first actuation module port and the second actuation module port, respectively, a secondary pedal sensor, a pump operable to displace fluid from the first brake circuit and the second brake circuit, a third controller programmed with an algorithm configured to receive a driver's braking request via the secondary pedal sensor and to output a signal to the pump to control the pump's output to the first brake circuit and the second brake circuit, and a first pair of ports coupled to the first pair of wheel cylinders and a second pair of ports coupled to the second pair of wheel cylinders, the modulation module being disposed between the first pair of wheel cylinders and the second pair of wheel cylinders and the first and second separated electro-hydraulic pressure supplies.In the primary brake-by-wire mode of operation, the master cylinder is in fluid communication only with the pedal feel simulator, and braking requests are configured to be satisfied by brake-by-wire operation of the first and second separate electro-hydraulic pressure supplies of the first and second actuation modules in accordance with the primary pedal sensor and algorithms of the first and second controllers. The vehicle braking system is configured to default to a redundant backup mode of operation when inoperable in the primary brake-by-wire mode of operation. In the redundant backup mode of operation, braking requests are configured to be satisfied by operation of the pump of the modulation module in accordance with the secondary pedal sensor and algorithms of the third controller.

[0004] In another aspect, the present disclosure provides a method for operating a vehicle braking system, the method including operating the vehicle braking system in a primary brake-by-wire mode. The primary brake-by-wire mode includes receiving, using a first controller, a first brake pedal signal from a primary pedal sensor that detects a first braking request. The primary brake-by-wire mode includes setting, using the first controller, a first command to a first fluid actuator, the first fluid actuator operable to displace fluid in a braking circuit to actuate a wheel cylinder coupled to the braking circuit. The primary brake-by-wire mode includes providing fluid to actuate the wheel cylinder via a modulation module disposed between the first fluid actuator and the wheel cylinder. The method includes operating the vehicle braking system in a backup brake-by-wire mode in response to the primary brake-by-wire mode being inoperative. The backup brake-by-wire mode includes receiving, using a controller of the modulation module, a second brake pedal signal from a pedal sensor of the modulation module that detects a second braking request. The backup brake-by-wire mode includes setting, with a controller of the coordination module, a second command to a fluid actuator of the coordination module, the fluid actuator of the coordination module operable to displace fluid in the braking circuit to actuate a wheel cylinder. [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a schematic diagram of a braking system of known construction; [Figure 2] FIG. 2 is a configuration diagram of the braking system of FIG. 1. [Figure 3] FIG. 1 is a schematic diagram of a braking system according to one embodiment of the present disclosure. [Figure 4] FIG. 4 is a block diagram of the braking system of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0006] Detailed Description Before describing any embodiment in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having," and variations thereof, herein is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items. The terms "mounted," "connected," and "coupled" are used broadly and encompass both direct and indirect mounting, connections, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, but can include hydraulic or electrical connections or couplings, whether direct or indirect.

[0007] 1 and 2 show a schematic representation of a vehicle braking system 100 of known construction. The vehicle braking system 100 can be used in passenger cars and light trucks (e.g., Class 1 and Class 2) having a gross vehicle weight rating (GVWR) of up to 10,000 pounds. Vehicles are classified by GVWR by a government agency, in the United States the Federal Highway Administration (FHWA), into Classes 1 and 2 as light-duty vehicles, Classes 3 through 6 as medium-duty vehicles, and Classes 7 and 8 as heavy-duty vehicles. Classes 3 through 6 vehicles have a GVWR between 10,001 and 26,000 pounds, while Classes 7 and 8 vehicles have a higher GVWR (26,001 pounds or greater). Specifically, Class 3 vehicles have a GVWR between 10,001 and 14,000 pounds, Class 4 vehicles have a GVWR between 14,001 and 16,000 pounds, Class 5 vehicles have a GVWR between 16,001 and 19,500 pounds, and Class 6 vehicles have a GVWR between 19,501 and 26,000 pounds. Vehicles with a GVWR less than 10,000 pounds can use a braking system 100 including a single actuation unit and a single modulation module, as described further below.

[0008] The vehicle braking system 100 is a brake-by-wire braking system including an actuation module 104, a modulation module 108 (e.g., a Bosch ESP® module), a driver interface 112 (e.g., a brake pedal), and a plurality of wheel cylinders 116 connected to the modulation module 108. Further details regarding the actuation module, the modulation module, and / or their functions are disclosed in U.S. Pat. Nos. 10,800,389, 12,194,972, and 2025 / 0091556, all of which are incorporated herein by reference in their entireties. Other documents in the art include U.S. Pat. No. 12,145,548, which also discloses a similar braking system having a pressure supply unit and a motor-pump unit. The entire contents of U.S. Pat. No. 12,145,548 are incorporated herein by reference. Aspects of the present disclosure may be applied as modifications or improvements to existing brake-by-wire braking systems, including but not limited to those described above.

[0009] As shown in FIG. 2 , the actuation module 104 is a single unit that includes a master cylinder 120 that is directly coupled to the brake pedal 112 via an input 124, such that the brake pedal 112 directly actuates the master cylinder 120 via the input 124. The vehicle braking system 100 further includes two separate braking circuits: a first braking circuit and a second braking circuit. The first braking circuit is responsible for actuating the wheel cylinders 116 of the front axle, and the second braking circuit is responsible for actuating the wheel cylinders 116 of the rear axle. In the illustrated configuration, the front axle includes two wheel cylinders 116, and the rear axle includes two wheel cylinders 116. Each braking circuit extends from the actuation module 104 into and through the adjustment module 108 to two of the four wheel cylinders 116. The first braking circuit is operable to route fluid from a first port 134 of the actuation module 104 through a port 138 of the regulation module 108 to two of the four wheel cylinders 116 via a first pair of ports 142 of the regulation module 108. The second braking circuit is operable to route fluid from a second port 146 of the actuation module 104 through a port 150 of the regulation module 108 to two of the four wheel cylinders 116 via a second pair of ports 154 of the regulation module 108.

[0010] The actuation module 104 includes a separate electro-hydraulic pressure supply 158 operable to pressurize fluid from the actuation module 104 to the wheel cylinders 116 in a brake-by-wire mode of operation. In other words, the separate electro-hydraulic pressure supply 158 is operable to supply fluid volume and / or pressure to the wheel cylinders 116. The master cylinder 120 and the separate electro-hydraulic pressure supply 158 are two fluid pressure supplies. The vehicle braking system 100 includes a third fluid pressure supply, i.e., a motor-driven pump, which will be described in more detail below.

[0011] As shown in FIG. 2 , the actuation module 104 includes a pedal feel simulator 160 selectively connected to the master cylinder 120. In some embodiments, the pedal feel simulator 160 relays feedback to the brake pedal 112 proportional to the user's displacement of the brake pedal 112. The force feedback becomes firmer the further the brake pedal 112 is depressed. In a brake-by-wire mode of operation, there is a direct relationship between the stroke input to the brake pedal 112 (i.e., travel distance, offset distance) and the input force required to move the brake pedal 112 that distance. Therefore, there is also a predetermined relationship relating the stroke input or travel distance of the brake pedal 112 to the reaction or feedback force provided by the pedal feel simulator 160. The pedal feel simulator 160 provides feedback to the brake pedal 112 according to fixed characteristics of the pedal feel simulator 160. In some configurations, the distance the user moves the brake pedal 112 (e.g., the displacement of the input 124) may be measured by a pedal travel sensor 162. Further details regarding a pedal feel simulator integrated into a master cylinder are disclosed in Robert Bosch GmbH's DE 102020202716 A1, the entire contents of which are incorporated herein by reference.

[0012] The regulation module 108 includes a second electronically controlled pressure generating unit, i.e., a motor-driven pump. The second pressure generating unit includes a motor 163 operable to drive a plurality of pumps 164, 165. Each of the pumps 164, 165 has an outlet coupled to pressurize two of the wheel cylinders 116 (e.g., the first pump 164 pressurizes the front wheel cylinder 116, and the second pump 165 pressurizes the rear wheel cylinder 116). In other words, the pump 164 pressurizes the first brake circuit, and the pump 165 pressurizes the second brake circuit. Alternatively, the first pump 164 may pressurize the left front wheel cylinder 116 and the right rear wheel cylinder 116, and the second pump 165 may pressurize the right front wheel cylinder 116 and the left rear wheel cylinder 116.

[0013] As mentioned above, the illustrated modulation module 108 includes port pairs 142, 154, each associated with a respective wheel cylinder 116. The modulation module 108 includes a number of valves that are selectively opened and closed via feedback from sensors (wheel speed sensors, yaw sensors, etc.) to control aspects of braking that would be possible with only the actuation module 104, such as an antilock braking system (ABS), traction control, or electronic stability program (ESP).

[0014] Vehicle braking system 100 further includes a controller 166 ( FIG. 2 ). Controller 166 may include several individual control units that function independently of one another. For example, in some configurations, actuation module 104 and regulation module 108 may include one control unit each that function independently of one another. Controller 166 is programmed to receive signals from various sensors of vehicle braking system 100. These sensors may include, for example, pressure sensors in the first circuit and / or the second circuit, and a pedal travel sensor 162 operable to measure input to brake pedal 112. Controller 166 is further operable to provide electrical signals to various components of vehicle braking system 100, for example, to operate motor 170 of first isolated electrohydraulic pressure supply 158, motor 163 of second electronically controlled pressure generating unit, and various valves. Controller 166 receives signals from pressure sensor 172.

[0015] Vehicle braking system 100 is operable in multiple modes, including a primary mode which is a brake-by-wire mode. In brake-by-wire mode, a user provides input to brake pedal 112, displacing a piston in master cylinder 120, thereby displacing fluid from master cylinder 120. In response to a signal from a sensor (e.g., a pressure sensor, pedal travel sensor 162, etc.), motor 170 of isolated electro-hydraulic pressure supply 158 is activated to exert a driving force, which displaces and pressurizes brake fluid to provide braking force at wheel cylinders 116. Valves are selectively opened to direct fluid from master cylinder 120 to pedal feel simulator 160 so that haptic feedback is provided to brake pedal 112, but master cylinder 120 does not contribute to braking at wheel cylinders 116.

[0016] Vehicle braking system 100 is operable in an alternate or "boost" mode. Boost mode is utilized when an operator provides input to brake pedal 112, but first separate electrohydraulic pressure supplier 158 provides a fluid volume and / or pressure to wheel cylinders 116 that is deemed insufficient by controller 166 for the braking demand at brake pedal 112. In boost mode, master cylinder 120 remains disconnected from wheel cylinders 116, and motor 163 of modulation module 108 operates pumps 164, 165 to draw fluid from reservoir 174 and provide additional volume and / or pressure to wheel cylinders 116 to replenish the fluid output from pressure supplier 158. Controller 166 controls modulation module 108 based on a signal from pedal travel sensor 162. Controller 166 further controls modulation module 108 based on a signal from pressure sensor 172. In other words, the controller 166 controls the adjustment module 108 based on signals from the pedal travel sensor 162 and / or the pressure sensor 172 .

[0017] In other modes, the modulation module 108 may act on its own to autonomously generate braking at the wheel cylinders 116 without any operator input to the brake pedal 112 (e.g., collision avoidance, adaptive cruise control, etc.).

[0018] In another alternative mode of operation, i.e., a "push-through" mode of operation, the master cylinder 120 is fluidly coupled to the wheel cylinders 116, where pressure applied to the master cylinder 120 by a user at the brake pedal 112 is transmitted to the wheel cylinders 116. The push-through mode of operation functions to provide redundancy in the event that the actuation module 104 is inoperable to perform braking in primary or brake-by-wire mode (i.e., due to a mechanical or electrical failure).

[0019] 3 illustrates a vehicle braking system 200 for use with vehicles having a GVWR greater than 10,000 pounds, and in some configurations, greater than 14,000 pounds, 16,000 pounds, or 19,500 pounds. Accordingly, the vehicle braking system can be used in medium and heavy-duty vehicles (i.e., Class 3 through Class 8). At GVWRs greater than 10,000 pounds, the fluid volume and / or pressure requirements of braking requirements may exceed the capabilities of commercially available actuation module 104 and modulation module 108 of vehicle braking system 100. In particular, larger vehicles capable of carrying heavier loads include wheel cylinders that consume substantially more fluid volume than actuation module 104 can provide in a push-through redundancy scenario. 1 and 2 could be redesigned with some form of braking assist functionality to specifically meet the needs of these larger vehicles, but allocating the large capital costs for development may be difficult when the total market for these vehicles is a small percentage of the more common passenger cars and light vehicles. Additionally, it should be noted that vehicle braking system 200 is also compatible with vehicles having a GVWR of less than 10,000 lbs.

[0020] 3 schematically illustrates a vehicle braking system 200 for a vehicle having a GVWR greater than 10,001 pounds (4,536 kg) in accordance with one embodiment of the present disclosure. In other words, the vehicle braking system 200 can be used with medium-sized vehicles (i.e., Class 3 to Class 6 vehicles) and heavy-duty vehicles (i.e., Class 7 to Class 8 vehicles). In other words, the vehicle braking system 200 can be used with Class 3, Class 4, Class 5, Class 6, Class 7, and / or Class 8 vehicles. The vehicle braking system 200 is a brake-by-wire braking system that includes a first actuation module 204, a second actuation module 208, a coordination module 212 (e.g., a Bosch ESP® module), and a plurality of wheel cylinders 216 (as illustrated, the vehicle braking system 200 includes four wheel cylinders 216) connected to the coordination module 212. First actuating module 204 supplies fluid pressure to wheel cylinders 216 of the front axle, and second actuating module 208 supplies fluid pressure to wheel cylinders 216 of the rear axle. In some embodiments, first actuating module 204 is a single unit including, for example, a housing 218 having a first port 220 for connecting to a first port 224 of adjustment module 212. In some embodiments, second actuating module 208 is a single unit including, for example, a housing 226 having a second port 228 for connecting to a second port 232 of adjustment module 212. In some embodiments, adjustment module 212 is a single unit including a housing 234 having first port 224 and second port 232 and ports 236, 240, 244, and 248. Vehicle braking system 200 includes two separate and independent braking circuits: a first braking circuit and a second braking circuit. The first braking circuit extends from the first actuation module 204 into and through the adjustment module 212 to two of the four wheel cylinders 216. In other words, the first braking circuit is responsible for actuating the wheel cylinders 216 on the front axle of the vehicle.Specifically, each of the adjustment modules 212 includes a first port 236 and a second port 240 (i.e., a first pair of ports) that couple to a respective wheel cylinder 216. The second braking circuit extends from the second actuating module 208 into and through the adjustment module 212 to two of the four wheel cylinders 216. In other words, the second braking circuit is responsible for actuating the wheel cylinders 216 of the rear axle of the vehicle. Specifically, the adjustment module 212 includes a third port 244 and a fourth port 248 (i.e., a second pair of ports), each of which couples to a respective wheel cylinder 216. The adjustment module 212 is fluidly disposed in series between each of the first actuating module 204 and the second actuating module 208 and the associated wheel cylinder 216.

[0021] The first actuation module 204 includes a first controller 252 programmed with an algorithm configured to receive a braking request and output a signal to control the output to the first brake circuit to satisfy the braking request to the associated wheel cylinder 216. The second actuation module 208 includes a second controller 256 programmed with an algorithm configured to receive a signal from the first controller 252 and output a signal to control the output to the second brake circuit to satisfy the braking request to the associated wheel cylinder 216. The coordination module 212 includes a third controller 260 (e.g., a backup brake-by-wire controller) programmed with an algorithm configured to receive a driver's braking request (among other inputs, such as wheel speed, yaw angle, and / or steering angle) and output signals to modify, including increase or decrease, the fluid pressure and / or volume to any one or more of the wheel cylinders 216 of the first and second brake circuits compared to the fluid pressure and / or volume output from the actuation modules 204, 208 to the respective ports 224, 232 of the coordination module 212. Thus, the coordination module 212 can selectively reduce or increase braking force at individual wheels of a vehicle having the braking system 200. As previously mentioned, the coordination module 212 provides these and other capabilities not possible with the actuation modules 204, 208 alone.

[0022] The first operating module 204, the second operating module 208, and the coordination module 212 are communicatively coupled to one another via a high-speed communication connection 264 (e.g., a CAN), which allows components such as the controllers 252, 256, and 260 of the first operating module 204, the second operating module 208, and the coordination module 212 to communicate with one another.

[0023] Additionally, first operating module 204 and second operating module 208 are provided with a first power supply 268, and regulation module 212 is provided with a second power supply 272. Second power supply 272 supplies power to regulation module 212 independently of first power supply 268 to provide redundancy in the event that first power supply 268 fails. In other words, second power supply 272 provides a redundant 12V power source to regulation module 212 such that second power supply 272 independently powers regulation module 212. In some configurations, first power supply 268 comprises a vehicle battery 276 and alternator 280 to power first operating module 204 and second operating module 208. In some configurations, second power supply 272 includes a battery 284 connected to first power supply 268 via a switch 288. A switch 288 allows the battery 284 of the second power source 272 to be recharged by either the alternator 280 or the battery 276 of the first power source 268 .

[0024] As shown in FIG. 4 , the vehicle braking system 200 includes a driver interface 292 (i.e., a brake pedal) configured to receive a braking request for operation by a driver. A first actuation module 204 is coupled to a first reservoir 296 and operable to provide fluid volume and / or pressure to a first braking circuit. The first actuation module 204 includes a master cylinder 300 that is directly associated with the brake pedal 292 via an input 304 (e.g., a rod). In other words, in contrast to the schematic diagram, the brake pedal 292 is external to the housing 218 of the first actuation module 204, and the input 304 is directly accommodated by the first actuation module 204. The brake pedal 292 directly actuates the master cylinder 300 via the input 304. The first actuation module 204 includes a pedal feel simulator 308 that is selectively coupled to the master cylinder 300. The pedal feel simulator 308 is configured to provide haptic feedback to the driver at the brake pedal 292 proportional to the user's displacement of the brake pedal 292. The first actuation module 204 includes a primary pedal sensor 312 configured to detect a braking input (representing a braking request) at the brake pedal 292 and output a signal to the first controller 252. In some configurations, the primary pedal sensor 312 is a force sensor. In some configurations, the primary pedal sensor 312 is a displacement sensor. The primary pedal sensor 312 is integrated into the housing 218 of the first actuation module 204. In some configurations, the primary pedal sensor 312 includes a magnetic needle coupled to the input rod 304 and sensing circuitry that detects the position of the magnetic needle. The first controller 252 is programmed with an algorithm configured to receive a signal from the primary pedal sensor 312 and output a signal to a first separate electro-hydraulic pressure supply 316 (e.g., a plunger, a linear actuator, etc.) to control the output to the first braking circuit. The first separate electro-hydraulic pressure supply 316 is operable to pressurize and depressurize fluid in the first brake circuit. The first separate electro-hydraulic pressure supply 316 may be referred to as a first fluid actuator.

[0025] In some configurations, the second actuation module 208 is a simplified or “reduced functionality” version of the first actuation module 204. The second actuation module 208 includes a second reservoir 320 operable to supply fluid to the second brake circuit. The second actuation module 208 includes a second separate electro-hydraulic pressure supply 324 (e.g., a plunger, a linear actuator, etc.). The second separate electro-hydraulic pressure supply 324 is operable to pressurize or depressurize fluid in the second brake circuit. The second separate electro-hydraulic pressure supply 324 may be referred to as a second fluid actuator. The second actuation module 208 includes a second controller 256 programmed with an algorithm configured to receive signals from the first controller 252 and output signals to the second separate electro-hydraulic pressure supply 324 to control the output to the second brake circuit. In some configurations, the second controller 256 does not receive a signal from the primary pedal sensor 312 and therefore relies on the first controller 252 to provide the braking request. In other words, the first actuation module 204 and the second actuation module 208 operate as a master unit and a slave unit. In some configurations, the first controller 252 simply transmits a signal from the primary pedal sensor 312 to the second controller 256. In some configurations, the first controller 252 transmits a calculated signal to the second controller 256 in response to receiving a signal from the primary pedal sensor 312, rather than simply transmitting the signal from the primary pedal sensor 312.

[0026] The coordinating module 212 includes a secondary pedal sensor 328. In the illustrated configuration, the secondary pedal sensor 328 is configured to detect a braking input (indicative of a braking request) from the brake pedal 292 and output a signal to the third controller 260. The signal from the secondary pedal sensor 328 to the third controller 260 is only transmittable or available when the braking system 200 is switched into a redundant backup mode. The primary pedal sensor 312 and the secondary pedal sensor 328 each detect a braking request independently of each other. Although the secondary pedal sensor 328 functions as part of the coordinating module 212, the secondary pedal sensor 328 is located outside the housing 234 of the coordinating module 212. In some configurations, the secondary pedal sensor 328 is physically coupled to a brake pedal box that houses the brake pedal 292. The brake pedal 292 is external to the housing 218 of the first actuation module 204. Thus, the brake pedal box and secondary pedal sensor 328 are external to the first actuation module 204. In the illustrated configuration, the secondary pedal sensor 328 includes an arm connected to the brake pedal 292. The secondary pedal sensor 328 is configured to detect movement of the brake pedal 292 (representing a braking request). In some configurations, the secondary pedal sensor 328 detects angular displacement of an arm connected to the brake pedal 292. In some configurations, the secondary pedal sensor 328 is a force sensor that detects a force acting on the brake pedal 292. In some embodiments, the secondary pedal sensor 328 is coupled to the brake pedal 292 and detects a driver force (representing a braking request). In some configurations, the secondary pedal sensor 328 is coupled to the input 304 and detects a driver force (representing a braking request). It should be noted that the force and displacement sensors described with respect to the secondary pedal sensor 328 can also be used with the primary pedal sensor 312. In some configurations, the secondary pedal sensor 328 is coupled to the housing 218 of the first actuation module 204 as an addition or modification to the first actuation module 204 .1 and 2 having an integrated pedal travel sensor 162. The secondary pedal sensor 328 may be inherent to the control system of the coordination module 212 (via the third controller 260 and the second power supply 272), despite being attached to the first coordination module 204. The secondary pedal sensor 328 may be configured to provide an output signal only to the third controller 260 (e.g., not communicate with the first controller 252 of the first coordination module 204). As described further below, the third controller 260 is programmed with a redundancy algorithm configured to receive the driver's braking request via the secondary pedal sensor 328. The coordination module 212 includes an electronically controlled pressure generating unit 332 (e.g., a fluid actuator) for providing fluid and / or volume to the first and second braking circuits. The pressure generating unit 332 includes a motor 336 operable to drive a plurality of pumps 340, 344. Each pump 340, 344 has an outlet coupled to pressurize two of the wheel cylinders 216. In other words, the first pump 340 pressurizes the wheel cylinders 216 for the front wheels, and the second pump 344 pressurizes the wheel cylinders 216 for the rear wheels. In other words, the pump 340 is configured to pressurize a first brake circuit, and the pump 344 is configured to pressurize a second brake circuit.

[0027] Braking system 200 is operable in at least three modes: a primary brake-by-wire mode; an alternate or "boost" mode of operation in which coordination module 212 is used as a boost in conjunction with first actuation module 204 and second actuation module 208; and a redundant brake-by-wire backup mode of operation in which coordination module 212 functions as a fully redundant actuation module (e.g., brakes when first actuation module 204 is inoperable). In the primary brake-by-wire mode of operation, first actuation module 204 and second actuation module 208 can provide sufficient fluid volume and pressure to actuate wheel cylinders 216 to meet braking demands without assistance from coordination module 212. Coordination module 212, similar to coordination module 108 of FIGS. 1 and 2, remains active in a standby state to intervene (e.g., ABS, traction control, stability control) as needed. In a boost mode of operation, the regulation module 212 provides a fluid volume and / or pressure to the wheel cylinders 216 to meet braking demands in addition to the fluid volume and / or pressure supplied by the first actuation module 204 and the second actuation module 208. In a brake-by-wire backup mode of operation, the regulation module 212 can provide sufficient fluid volume and / or pressure to operate the wheel cylinders 216 to meet braking demands without assistance from the first actuation module 204 and the second actuation module 208.

[0028] Unlike the vehicle braking system 100 of FIGS. 1 and 2, the braking system 200 does not rely on a push-through mode of operation in which pressure applied by a user at the brake pedal 292 is transmitted to the wheel cylinders 216. This is because a braking system 200 designed for a vehicle having a GVWR greater than 10,001 pounds includes a master cylinder 300 that is miniaturized (e.g., sized for a vehicle having a GVWR less than 10,001 pounds) and therefore unable to provide sufficient fluid volume and / or pressure to actuate the wheel cylinders 216 to meet minimum braking performance. For example, in order for the master cylinder to provide sufficient fluid volume for redundant actuation via push-through in a vehicle having a GVWR greater than 10,001 pounds, the master cylinder may displace a total fluid volume of between 80 cc and 120 cc. For reference, the master cylinder 300 in the braking system 200 may have a total fluid volume of less than 60 cc. The master cylinder 300 can have a total fluid capacity between 5 cc and 50 cc. The master cylinder 300 can have a total fluid capacity of 40 cc or less, 30 cc or less, or 20 cc or less. Specifically, in some configurations, the master cylinder 300 has a total fluid capacity of 15 cc. To compensate for a master cylinder incapable of push-through mode of operation, the braking system 200 utilizes a coordination module 212 to provide fully redundant operation via the coordination module 212 taking over from the first actuating module 204 and the second actuating module 208, as described further below.

[0029] In the primary brake-by-wire mode of operation, the brake pedal 292 is engaged by the driver such that the primary pedal sensor 312 detects a braking input from the brake pedal 292. The first chamber 348 of the master cylinder 300 is switched by a valve into communication with the pedal feel simulator 308, and the second chamber 352 of the master cylinder 300 remains disconnected from the wheel cylinders 216. When the driver displaces the brake pedal 292 to establish a braking request, the primary pedal sensor 312 detects the braking input from the brake pedal 292 and outputs a signal to the first controller 252. An algorithm in the first controller 252 receives the signal from the primary pedal sensor 312 and outputs a signal to the first isolated electro-hydraulic pressure supplier 316 to supply fluid to actuate the wheel cylinders 216 of the first brake circuit to satisfy the braking request in the first brake circuit. Additionally, the algorithm of the first controller 252 outputs signals to the controllers of the second actuation module 208 and the adjustment module 212 .

[0030] Specifically, the algorithm of the first controller 252 outputs a signal to the algorithm of the second controller 256 in response to the braking response detected by the primary pedal sensor 312. After receiving the signal, the algorithm of the second controller 256 outputs a signal to the second separate electrohydraulic pressure supplier 324 to supply fluid to actuate the wheel cylinders 216 of the second brake circuit to satisfy the braking request in the second brake circuit. In the primary brake-by-wire operating mode, the driver's braking request is satisfied by the first actuation module 204 and the second actuation module 208. In other words, the adjustment module 212 does not contribute to the braking request.

[0031] In some configurations, the algorithm of the first controller 252 outputs a signal to the third controller 260. The algorithm of the third controller 260 does not provide fluid pressure and / or volume to the first or second braking circuits in response to the signal. In other words, although the secondary pedal sensor 328 detects a braking input from the brake pedal 292, the modulation module 212 does not contribute to the braking response because the first actuation module 204 and the second actuation module 208 provide sufficient fluid volume and pressure to actuate the wheel cylinders 216 to satisfy the braking demand.

[0032] In the boost mode of operation, the first and second separate electro-hydraulic pressure supplies 316, 324 operate normally but do not generate sufficient fluid volume and / or pressure to the wheel cylinders 216. In the boost mode, the master cylinder 300 remains disconnected from the wheel cylinders 216. In the boost mode, the third controller 260 receives the driver's braking request via the first controller 252 and outputs a signal to the pressure generation unit 332 to control the output to the first and second brake circuits. Stated another way, the motor 336 of the pressure generating unit 332 operates the pumps 340, 344 to draw fluid from the reservoirs 296, 320 and provide additional fluid volume and / or pressure to the wheel cylinders 216 in addition to the fluid volume and / or pressure provided by the first and second separate electro-hydraulic pressure supplies 316, 324 of the first and second actuating modules 204, 208. In other words, the pressure generating unit 332 operates in response to a signal from the first actuating module 204.

[0033] In other modes, apart from the redundant backup, the modulation module 212 can act on its own to autonomously generate braking at the wheel cylinders 216 without any operator input to the brake pedal 292 (e.g., collision avoidance, adaptive cruise control, etc.).

[0034] In the redundant backup mode of operation, the brake pedal 292 is engaged by the driver such that the primary pedal sensor 312 and the secondary pedal sensor 328 detect a braking input from the brake pedal 292. The algorithms of the first controller 252 and the third controller 260 communicate with each other, and the algorithm of the third controller 260 identifies that the first actuation module 204 and the second actuation module 208 are inoperable and cannot contribute to the braking response. Alternatively, the algorithm of the third controller 260 may identify a lack of communication with the first controller 252. In response to identifying the first actuation module 204 and the second actuation module 208 and / or the first controller 252 as inoperable, the third controller 260 takes over control as the main controller of the braking system 200, and the coordination module 212 takes over control as the actuation module for operation. For example, the valves of the first actuating module 204 and the second actuating module 208 may each assume a quiescent state, causing the first actuating module 204 to mimic a push-through configuration in which the master cylinder 300 is connected to the regulating module 212 (and disconnected from the pedal feel simulator) and the first isolated electro-hydraulic pressure supplier 316 is disconnected from the circuit. However, like the primary brake-by-wire mode, the redundant backup mode is also a brake-by-wire mode in which the driver's braking demand is determined by sensing the driver's input and may be satisfied primarily by electronic devices separate from the master cylinder 300. An algorithm in the third controller 260 outputs signals to the motor 336 to cause multiple pumps 340, 344 to supply fluid pressure and volume to the wheel cylinders 216 in the first brake circuit and the wheel cylinders 216 in the second brake circuit. In the redundant backup mode, the regulation module 212 is operable to draw fluid from the reservoirs 296 , 320 via the first actuation module 204 and the second actuation module 208 .In this manner, the adjusting module 212 can also draw fluid from the master cylinder 300, thereby disabling master cylinder pressure sensing that might otherwise be used when the adjusting module 212 is actively in use. Because conventional adjusting modules rely on master cylinder pressure sensing within the first actuating module 204, conventional adjusting modules are inoperable in the redundant backup mode of the braking system 200. Because the adjusting module 212 pumps a large volume of fluid from the first actuating module 204, the pressure within the first actuating module 204 drops, providing an inaccurate representation of the braking request. Therefore, the secondary pedal sensor 328 functions to accurately detect the braking input of the brake pedal 292 and output a signal regardless of whether fluid is being drawn from the first actuating module and the second actuating module, allowing full functionality of the adjusting module 212 in the redundant backup mode. Operation in the redundant backup mode is not dependent on the power or signal used to operate the primary brake-by-wire mode. The braking system 200 is configured to normally operate in a primary mode and to automatically default to a redundant backup mode of operation if the primary mode is inoperable.

[0035] Various features of the present disclosure are set forth in the following claims.

Claims

1. 1. A vehicle braking system comprising: a brake pedal configured to receive a braking request for operation by a driver; a first operational module, a master cylinder coupled to the brake pedal for displacing fluid in response to braking demands from the driver; a pedal feel simulator coupled to the master cylinder and configured to provide haptic feedback to the brake pedal in response to the braking request; A primary pedal sensor; a first separate electro-hydraulic pressure supply operable to displace a fluid; a first controller programmed with an algorithm configured to receive a signal from the primary pedal sensor and to output a signal to the first separate electro-hydraulic pressure supplier to control the output of the first separate electro-hydraulic pressure supplier to a first brake circuit terminating in a first pair of wheel cylinders; a first working module port; a first operating module including: a second operating module, a second separate electrohydraulic pressure supply operable to displace said fluid; a second controller programmed with an algorithm for receiving signals from the first controller and for outputting signals to the second separate electro-hydraulic pressure supplier to control the output of the second separate electro-hydraulic pressure supplier to a second brake circuit terminating in a second pair of wheel cylinders; a second working module port; a second operating module including: an adjustment module, a first port and a second port coupled to the first working module port and the second working module port, respectively; A secondary pedal sensor; a pump operable to displace fluid from the first brake circuit and the second brake circuit; a third controller programmed with an algorithm configured to receive the driver's braking request via the secondary pedal sensor and to output a signal to the pump to control the output of the pump to the first brake circuit and the second brake circuit; a first pair of ports coupled to the first pair of wheel cylinders and a second pair of ports coupled to the second pair of wheel cylinders; an adjustment module including: Equipped with the adjustment module is disposed between the first pair of wheel cylinders and the second pair of wheel cylinders and the first separate electro-hydraulic pressure supplier and the second separate electro-hydraulic pressure supplier; In a primary brake-by-wire mode of operation, the master cylinder is in fluid communication only with the pedal feel simulator, and the braking request is satisfied by brake-by-wire operation of the first and second separate electro-hydraulic pressure supplies of the first and second actuation modules in accordance with the primary pedal sensor and algorithms of the first and second controllers; the vehicle braking system is configured to default to a redundant backup mode of operation when the vehicle braking system is inoperable in the primary brake-by-wire mode of operation; In the redundant backup mode of operation, the braking demand is configured to be satisfied by operation of the pump of the regulation module in accordance with the secondary pedal sensor and an algorithm of the third controller. Vehicle braking system.

2. The vehicle braking system further comprises: a first power source configured to provide power to the first operating module; a second power source configured to provide power to the conditioning module; 10. The vehicle braking system of claim 1, comprising:

3. The vehicle braking system of claim 2 , wherein the first power source is configured to power the second separate electrohydraulic pressure supply.

4. 2. The vehicle braking system of claim 1, wherein the second actuation module does not have a master cylinder and operates as a slave module to the first actuation module in the primary brake-by-wire mode.

5. the first actuation module includes a housing; the adjustment module includes a housing separate from the housing of the first actuation module; 2. The vehicle braking system of claim 1, wherein the secondary pedal sensor is mounted to the brake pedal.

6. A vehicle equipped with the vehicle braking system of claim 1, the master cylinder has a total fluid capacity of less than 60 cc; The vehicle has a gross vehicle weight rating of more than 4,536 kg.

7. 7. The vehicle of claim 6, wherein the master cylinder has a total fluid capacity of 30 cc or less.

8. 8. The vehicle of claim 7, wherein the vehicle has a gross vehicle weight rating of greater than 6350 kg.

9. 1. A method of operating a vehicle braking system, the method comprising: operating the vehicle braking system in a primary brake-by-wire mode, The primary brake-by-wire mode is receiving, with a first controller, a first brake pedal signal from a primary pedal sensor detecting a first braking request; setting, with the first controller, a first command to a first fluid actuator, the first fluid actuator operable to displace fluid in the braking circuit to actuate a wheel cylinder coupled to the braking circuit; providing fluid for actuating the wheel cylinder via a regulator module disposed between the first fluid actuator and the wheel cylinder; Including, operating the vehicle braking system in a primary brake-by-wire mode; responsive to the primary brake-by-wire mode being inoperable, operating the vehicle braking system in a backup brake-by-wire mode; The backup brake-by-wire mode is receiving, using a controller of the coordination module, a second brake pedal signal from a pedal sensor of the coordination module detecting a second braking request; setting, with a controller of the coordination module, a second command to a fluid actuator of the coordination module, the fluid actuator of the coordination module operable to displace fluid in the braking circuit to actuate the wheel cylinder; Including, operating the vehicle braking system in a backup brake-by-wire mode; A method comprising:

10. The method of claim 9 , further comprising powering the first controller, the primary pedal sensor, and the first fluid actuator with a first power source.

11. 10. The method of claim 9, further comprising powering the controller of the adjustment module, the pedal sensor of the adjustment module, and the fluid actuator of the adjustment module using a second power source.

12. The operation in the primary brake-by-wire mode further includes: receiving a signal from the first controller using a second controller; setting a command to a second fluid actuator with the second controller, the second fluid actuator operable to displace fluid in the braking circuit to actuate the wheel cylinder; 10. The method of claim 9, comprising:

13. The method of claim 9 , wherein receiving the second brake pedal signal from the pedal sensor of the modulation module is limited to the controller of the modulation module.

14. 10. The method of claim 9, wherein detecting the second braking request with the pedal sensor of the modulator module is independent of the primary pedal sensor.

15. 10. The method of claim 9, wherein detecting the first braking request with the primary pedal sensor further comprises detecting a position of an input rod coupled to the brake pedal.

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