Redundant Electronic Stability Control-Based Braking System

Abstract

To provide a braking system capable of being used for level 4 automated driving.SOLUTION: A brake system comprises an electronic stability control (ESC) module and a pressure supply unit (PSU) module. The ESC module has a first interconnect passage. The PSU module has a second interconnect passage in a state in fluid communication with the first interconnect passage. The ESC module has a first pump and a prime valve. The first pump is configured to transfer brake fluid from the PSU module and to a plurality of wheel brakes. The prime valve is configured to selectively control fluid communication between the first interconnect passage and an inlet of the first pump. The PSU module has a second pump configured to transfer the brake fluid from a fluid reservoir to the first interconnect passage, and a bypass fluid passage from the fluid reservoir to the ESC module. The bypass fluid passage has an inline check valve allowing fluid flow through the inside of the bypass fluid passage from the fluid reservoir and to the ESC module while blocking fluid flow in an opposite direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates generally to a braking system for a vehicle (e.g., an automobile). In particular, the present disclosure relates to a braking system that can be used in Level 4 autonomous driving. [Background technology]

[0002] In automotive vehicles there is a need for braking without driver input. Typically a solution to this is provided by a one-box braking system where brake application and brake modulation (ABS / ESC) are all configured within one hardware box. Additional braking units are either built into the one-box or added separately to provide redundancy for brake application and possibly also brake modulation (ABS / ESC). This type of system can be very useful but can be quite expensive. Summary of the Invention [Problem to be solved by the invention]

[0003] The present disclosure provides a braking system that can be used in Level 4 autonomous driving. [Means for solving the problem]

[0004] The present invention provides a braking system for an automotive vehicle. The braking system includes two brake-related modules: an electronic stability control (ESC) module and a pressure supply unit (PSU) module. The electronic stability control (ESC) module has a first interconnection passage. The pressure supply unit (PSU) module has a second interconnection passage in fluid communication with the first interconnection passage of the ESC module. The ESC module has a first pump and a prime (first) valve. The first pump is configured to deliver braking fluid from the PSU module to a plurality of wheel brakes. The prime valve is configured to selectively control fluid communication between the first interconnection passage and an inlet of the first pump. The PSU module has a second pump and a bypass fluid passage. The second pump is configured to deliver braking fluid from a fluid reservoir to the first interconnection passage of the ESC module. The bypass fluid passage has an in-line check valve. The bypass fluid passage is configured to deliver braking fluid from the fluid reservoir directly to the ESC module while bypassing the second pump. The in-line check valve is configured to allow fluid flow from the fluid reservoir through the bypass fluid passage to the ESC module while blocking fluid flow in the opposite direction. The PSU module further includes a pressure control valve configured to control fluid flow between the second interconnecting passage and the bypass fluid passage to control fluid pressure. The PSU module further includes an isolation valve for controlling fluid flow between the outlet of the second pump and the second interconnecting passageway, The isolation valve being a normally open linear valve capable of variable control of flow therethrough.

[0005] The present invention also provides a braking system for an automotive vehicle. The braking system includes an electronic stability control (ESC) module and a pressure supply unit (PSU) module. The electronic stability control (ESC) module has a first interconnection passage. The pressure supply unit (PSU) module has a second interconnection passage in fluid communication with the first interconnection passage of the ESC module. The ESC module has a first electronic control unit (ECU) and a first pump. The first pump is configured to pump brake fluid from the PSU module to a plurality of wheel brake devices. The PSU module has a second ECU, a second pump, and a bypass fluid passage. The second pump is configured to pump brake fluid from a fluid reservoir to the first interconnection passage of the ESC module. The bypass fluid passage includes an in-line check valve. The bypass fluid passage is configured to route brake fluid from the fluid reservoir directly to the ESC module while bypassing the second pump. The in-line check valve is configured to allow fluid flow from the fluid reservoir to the ESC module through the bypass fluid passage while blocking fluid flow in the opposite direction.

[0006] Other advantages of the present invention will become better understood as the same becomes better understood with reference to the following detailed description when considered in conjunction with the accompanying drawings. [Brief description of the drawings]

[0007] [Figure 1] 1 shows a schematic diagram of a first braking system according to one aspect of the present disclosure. [Diagram 2] FIG. 2 shows a schematic diagram of a second braking system according to one aspect of the present disclosure. [Diagram 3] FIG. 2 shows a schematic block diagram illustrating the functional interconnections between vehicle systems having a second braking system. [Figure 4] FIG. 2 shows a schematic block diagram illustrating the hydraulic interconnections of the second braking system. [Diagram 5] FIG. 2 shows a schematic block diagram illustrating the electrical interconnections of the second braking system. [Figure 6] FIG. 2 shows a schematic diagram of a second braking system according to one aspect of the present disclosure. [Figure 7] 1 shows a schematic diagram of a third braking system according to one aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will be described in detail based on the following embodiments with reference to the drawings.

[0009] The disclosed system may be applicable to Level 4 and above automation based on the SAE (Society of Automotive Engineers) International "Levels of Autonomy" standard, which defines six levels of automation as defined in SAE Standard J3016. Level 4 automation provides fully automated (i.e., driverless) vehicles, but may be limited in speed and area. Such vehicles may include shuttles that travel around a defined area to carry passengers or cargo at a certain maximum speed.

[0010] The braking system of the present disclosure can interface with an autonomous vehicle controller and software stack that can command the braking unit via CAN messaging or alternative bus messaging to apply the required level of braking.

[0011] This disclosure provides for braking to be performed by two off-the-shelf Electronic Stability Control (ESC) units, one of which is modified with a special Pressure Supply Unit (PSU) configured to provide redundancy, and an additional benefit provided in this dual module approach is distributed EPB (Electric Park Brake) control, providing continued EPB functionality to actuate the electric parking brake in the event of an ECU (Electronic Control Unit) failure.

[0012] The braking system of the present disclosure can have one fully standard 12 valve ESC unit and one PSU unit, both providing redundant braking action, as well as providing standard ABS / ESC in an economical two-box package. Operational redundancy is provided by one ESC unit and one PSU unit in series. ABS / ESC modulation is provided by the ESC unit. Each unit can provide braking action. In some embodiments, typical braking action functions can alternate between each unit with each brake application. This allows wear on the units to be evenly distributed between each unit.

[0013] FIG. 1 shows a schematic diagram of a first braking system 10 according to one embodiment of the present disclosure. The first braking system 10 is configured to provide redundant braking operation required for level 4 and above automation. The first braking system 10 has a main electrohydraulic control unit (EHCU) 20 hydraulically connected to four wheel brakes 22a, 22b, 22c, 22d. The main EHCU 20 can be a full-function device that generates fluid pressure for application to each of the wheel brakes 22a, 22b, 22c, 22d and controls the distribution of fluid to provide functions such as anti-lock braking, electronic stability control, etc. Each of the wheel brakes 22a, 22b, 22c, 22d can be connected to a corresponding wheel (not shown) of the vehicle and can be referred to as a foundation brake for the function of stopping the vehicle. The fallback EHCU 24 is hydraulically connected to the primary EHCU 20 to provide fluid to operate the wheel brakes 22a, 22b, 22c, 22d if the primary EHCU 20 is unavailable, and communicates with the primary EHCU 20 via a Controller Area Network (CAN) interconnect 26, although other communication interfaces may be used.

[0014] Although the first braking system 10 may work well, the cost of the main EHCU 20 is very high due to the inclusion of components such as brushless motors, ball screws and corresponding control means required for the system to function properly. The response time of this type of unit is very fast, much faster than is often required for Level 4 where speed limits are constrained.

[0015] FIG. 2 shows a schematic diagram of a second braking system 50 according to one embodiment of the present disclosure. The second braking system 50 is also configured to provide redundant braking operation required for Level 4 and above automation. The second braking system 50 has a cost advantage over the first braking system 10. The second braking system 50 includes an electronic stability control (ESC) module 52 and a PSU module 54 that are packaged similarly to the ESC module 52 and share common components. The ESC module 52 and the PSU module 54 can be derived from the same basic ESC design package, reducing manufacturing costs. The ESC module 52 can be a full-function ESC, while the PSU module 54 can be used primarily for fallback and basic brake application. If automatic braking is required at any speed, either the ESC module 52 or the PSU module 54 can provide braking. A reservoir 58 contains fluid and is used directly by the PSU module 54 or indirectly by the ESC module 52.

[0016] The ESC module 52 and the PSU module 54 may each include a pump driven by an electric motor and one or more solenoid valves for controlling the distribution of pressurized fluid to operate the wheel brakes 22a, 22b, 22c, 22d. The ESC module 52 and the PSU module 54 may be configured as an integrated package including a pump and corresponding motor, an electronic control unit (ECU), and a hydraulic control unit (HCU) having valves with associated fluid passages and hydraulics for distributing brake fluid to operate the wheel brakes 22a, 22b, 22c, 22d. The ESC module 52 and the PSU module 54 may also be housed in a nearly identical module, such as in a DBC1280 ESC device. The second braking system 50 may also use regenerative braking, especially at higher speeds.

[0017] The second braking system 50 also includes two of the rear wheel brakes 22c, 22d of the wheel brakes 22a, 22b, 22c, 22d configured with an electric parking brake (EPB) caliper 56. Each of these EPB calipers 56 includes an electric actuator configured to apply a brake in addition to or instead of applying a hydraulic pressure. In other words, each of the EPB calipers 56 can provide a braking force in response to either or both of an electrical signal and a hydraulic brake pressure supply. Alternatively or additionally, the two rear wheel brakes 22c, 22d of the wheel brakes 22a, 22b, 22c, 22d can also be configured with an EPB caliper 56. In an embodiment, each of the ESC modules 52 and the PSU module 54 can be configured to control one or more of the EPB calipers 56. For example, the ECU of the ESC module 52 may control one of the two EPB calipers 56 corresponding to the right rear brake 22c, and the ECU of the PSU module 54 may control the other EPB caliper 56 corresponding to the left rear brake 22d. Such a configuration may provide increased safety and / or redundancy in the event of an ECU failure.

[0018] FIG. 3 shows a schematic block diagram illustrating the functional interconnections between vehicle systems with the second braking system 50. FIG. 3 shows a vehicle with a propulsion subsystem 60 that can also provide regenerative braking functionality. The propulsion subsystem 60 can include one or more electric machines, such as a motor / generator. The propulsion subsystem 60 can include other associated devices, such as an inverter, an electronic control unit, a battery, etc. FIG. 3 also shows an autonomous driving (AD) electronic control unit (ECU) 62. The AD-ECU 62 provides an AD stack that is in functional communication with each of the propulsion subsystem 60 and the second braking system 50. The AD-ECU 62 can include hardware and / or software configured to coordinate the autonomous driving functions of the vehicle. The AD-ECU 62 can be responsible for propulsion and braking. The AD-ECU 62 can control regenerative braking. Regenerative braking can be used for most braking above a certain speed. Below a certain speed, the ECUs 80, 180 of the ESC module 52 and PSU module 54 of the second braking system 50 may control braking to a stop.

[0019] The ESC module 52 and PSU module 54 of the second braking system 50 are operable to slow or stop the vehicle and may perform the following functions:

[0020] Each of the ESC module 52 and the PSU module 54 has a corresponding brake modulator. Either or both of the brake modulators can apply brake fluid to the wheel brakes 22a, 22b, 22c, and 22d to provide redundant braking. The brake modulators can have pumps to provide brake fluid to the wheel brakes 22a, 22b, 22c, and 22d. The ESC module 52 and the PSU module 54 can alternate brake application duties to balance wear between the modules. In some embodiments, automatic emergency braking (AEB), anti-lock braking (ABS), dynamic rear proportioning (DRP) used to maintain front and rear brake balance, and / or electronic stability control (ESC) functions can also be supported by the ESC module 52 or the PSU module 54. The pump runtimes in the ESC module 52 and the PSU module 54 can be logged and reported for maintenance purposes.

[0021] Figure 4 shows a schematic block diagram illustrating the hydraulic interconnections of the second braking system 50. As shown in Figure 4, each wheel brake 22a, 22b, 22c, 22d is connected to a corresponding wheel 23a-23d for applying a braking force thereto. A fluid reservoir 58 is connected to the PSU module 54 for supplying braking fluid to the PSU module 54.

[0022] 6, each of the rear wheel braking devices 22c, 22d has an electric parking brake EPB. The electric parking brake EPB of the right rear wheel braking device 22c is electrically connected to the second brake ECU 180. The electric parking brake EPB of the left rear wheel braking device 22d is electrically connected to the first brake ECU 80. This configuration provides redundancy for the electric parking brake EPB even in the unlikely event that one of the brake ECUs 80, 180 loses power or becomes unusable.

[0023] FIG. 5 shows a schematic block diagram of the electrical interconnections of the second braking system 50. As shown in FIG. 5, a corresponding wheel speed sensor 70a-70d is connected to each wheel 23a-23d to measure the rotational speed of the wheel. The front wheel speed sensors 70a, 70b are connected to the first brake ECU 80. The rear wheel speed sensors 70c, 70d are connected to the second brake ECU 180. This configuration provides redundancy for the wheel speed sensors 70a, 70b and the wheel speed sensors 70c, 70d in the unlikely event that one of the brake ECUs 80, 180 loses power or becomes unavailable. Both the first brake ECU 80 and the second brake ECU 180 are functionally connected to the AD·ECU 62. A first power source (e.g., a first battery 72) is connected to the ESC module 52 to provide standby (backup) power. And a second power source (e.g., a second battery 74) is connected to the PSU module 54 to provide standby power. In this manner, the ESC module 52 and the PSU module 54 each have a separate and independent standby power supply.

[0024] 6 shows a schematic diagram of the second braking system 50 showing details of the ESC module 52 and the PSU module 54 and their interconnections. The modules include two separate and independent braking circuits, each having associated components referred to as primary and secondary components. Each of the separate and independent braking circuits can operate under normal conditions and can provide redundancy, such that either of the braking circuits can provide braking function, even if a critical failure, such as a major fluid leak, occurs in the other braking circuit.

[0025] 6, the ESC module 52 includes a first main interconnect passage 76 with a corresponding main inlet 77 and a first secondary interconnect passage 78 with a corresponding secondary inlet 79. The ESC module 52 also includes a first brake ECU 80 and a first pump 82 having a first motor 84 controlled by the first brake ECU 80. For example, the first brake ECU 80 can provide control power, such as pulse width modulated (PWM) AC power, to the first motor 84 to control the speed of the first motor 84. The first pump 82 also includes a first main pump element 85 and a first secondary pump element 86. The first main pump element 85 and the first secondary pump element 86 are each connected to the first motor 84 to supply fluid through a corresponding brake circuit. The steering angle sensor 64 is in functional communication with the first brake ECU 80 to communicate steering angle data. The first brake ECU 80 can use the steering angle data and / or other vehicle data to adjust one or more parameters related to the operation of the brakes.

[0026] The ESC module 52 has a main supply fluid passage 88 configured to route fluid from the first main pump element 85 of the first pump 82 to the two wheel brake devices 22a, 22b. The ESC module 52 also has a secondary supply fluid passage 89 configured to route fluid from the first secondary pump element 86 of the first pump 82 to the other two wheel brake devices 22c, 22d. The ESC module 52 has a main return fluid passage 90 configured to route fluid from the corresponding wheel brake devices 22a, 22b to the first main pump element 85 of the first pump 82. The ESC module 52 also has a secondary return fluid passage 91 configured to route fluid from the corresponding wheel brake devices 22c, 22d to the first secondary pump element 86 of the first pump 82.

[0027] Accumulators 92 are connected to the respective return fluid passages 90, 91 to hold fluid from the corresponding brakes of the wheel brake devices 22a, 22b, 22c, 22d and to supply fluid to the corresponding pump elements 85, 86. Each of the accumulators 92 may have a spring-loaded piston movable in a bore to hold fluid therein. It is noted that one or both of the accumulators 92 may be configured differently. A return check valve 93 is disposed between each of the return fluid passages 90, 91 and the corresponding one of the first pump elements 85, 86 to allow fluid flow from the return fluid passages 90, 91 to the corresponding one of the first pump elements 85, 86 while blocking fluid flow in the opposite direction.

[0028] The ESC module 52 also includes a first noise damper 94 disposed between the outlet of each of the first pump elements 85, 86 and the corresponding supply fluid passages 88, 89. Each of the first noise dampers 94 includes a restrictor orifice and a blow-off valve. The restrictor orifice is connected to the outlet of the corresponding first pump element 85, 86. The blow-off valve is in parallel with the restrictor orifice and can restrict flow under low hydraulic flow conditions and not restrict hydraulic flow under high flow restriction. The ESC module 52 also includes an elastomer damper 95 connected to the outlet of each of the first pump elements 85, 86 to reduce pressure pulsing of the fluid supplied from the first pump element and further reduce noise.

[0029] The ESC module 52 has an application valve 96a and a release valve (relief valve) 96b associated with each of the wheel brake devices 22a, 22b, 22c, 22d to control the flow of fluid to and from the wheel brake devices 22a, 22b, 22c, 22d. The application valve 96a is configured to control the flow of fluid from a corresponding one of the supply fluid passages 88, 89 to a corresponding one of the wheel brake devices 22a, 22b, 22c, 22d. The relief valve 96b is configured to control the flow of fluid from a corresponding one of the wheel brake devices 22a, 22b, 22c, 22d to a corresponding one of the supply fluid passages 88, 89 and to a corresponding one of the return fluid passages 90, 91.

[0030] The ESC module 52 also has a primary prime valve 100 configured to selectively control fluid communication between the first primary interconnecting passage 76 and an inlet of the first primary pumping element 85 of the first pump 82. The ESC module 52 also has a secondary prime valve 102 configured to selectively control fluid communication between the first secondary interconnecting passage 78 and an inlet of the first secondary pumping element 86 of the first pump 82. The prime valves 100, 102 may each be a normally closed solenoid valve.

[0031] The ESC module 52 also includes a first main pressure control valve 104 hydraulically connected between the first main interconnect passage 76 and the main supply fluid passage 88 to control the fluid pressure in the first main interconnect passage 76. The ESC module 52 also includes a first secondary pressure control valve 106 hydraulically connected between the first secondary interconnect passage 78 and the secondary supply fluid passage 89 to control the fluid pressure in the first secondary interconnect passage 78. The first pressure control valves 104, 106 may each be a normally open linear separation valve having variable control of the pressure therethrough. The ESC module 52 also includes a first pressure sensor 108 configured to monitor the fluid pressure in the first main interconnect passage 76. The first pressure sensor 108 is connected to the first brake ECU 80 to communicate the measured pressure.

[0032] 6, the PSU module 54 has a second main interconnect passage 176 with a corresponding main outlet 177. The main outlet 177 is fluidly connected to the main inlet 77 of the ESC module 52 to provide fluid to the second main interconnect passage 176. The PSU module 54 also has a second secondary interconnect passage 178 with a corresponding secondary outlet 179. The secondary outlet 179 is fluidly connected to the secondary inlet 79 of the PSU module 54 to provide fluid to the second secondary interconnect passage 178. The PSU module 54 also includes a second brake ECU 180 and a second pump 182 having a second motor 184 controlled by the second brake ECU 180. For example, the second brake ECU 180 can provide control power, such as pulse width modulated (PWM) AC power, to the second motor 184 to control the speed of the second motor 184. The second pump 182 also includes a second primary pump element 185 and a second secondary pump element 186. The second primary pump element 185 and the second secondary pump element 186 are each connected to the second motor 184 for supplying fluid through a corresponding brake circuit. The second primary pump element 185 is configured to pump brake fluid from the fluid reservoir 58 to the first primary interconnect passage 76 of the ESC module 52 via the second primary interconnect passage 176. The second secondary pump element 186 is configured to pump brake fluid from the fluid reservoir 58 to the first secondary interconnect passage 78 of the ESC module 52 via the second secondary interconnect passage 178.

[0033] The PSU module 54 has a primary reservoir fluid passage 188 configured to route fluid from the fluid reservoir 58 to a second primary pump element 185 of the second pump 182 via a primary reservoir port Rp. The PSU module 54 also has a secondary reservoir fluid passage 189 configured to route fluid from the fluid reservoir 58 to a second secondary pump element 186 of the second pump 182 via a secondary reservoir port Rs. The PSU module 54 has a primary bypass fluid passage 190. The primary bypass fluid passage 190 provides fluid communication between the primary reservoir fluid passage 188 and the second primary interconnect passage 176 to route brake fluid from the fluid reservoir 58 directly to the ESC module 52, bypassing the second pump 182. The PSU module 54 has a secondary bypass fluid passage 191. The secondary bypass fluid passage 191 provides fluid communication between the secondary reservoir fluid passage 189 and the second secondary interconnect passage 178 to route brake fluid directly from the fluid reservoir 58 to the ESC module 52, bypassing the second pump 182. An in-line check valve 193 is disposed in a fluid path between each of the second interconnect passages 176, 178 and its corresponding one of the bypass fluid passages 190, 191. Each in-line check valve 193 is configured to allow fluid to flow from the fluid reservoir 58 through the corresponding one of the bypass fluid passages 190, 191 to the ESC module 52 via the corresponding one of the second interconnect passages 176, 178 while blocking fluid flow in the opposite direction. Each check valve 193 provides a low blow-off pressure such that fluid can flow therethrough only at a predetermined fluid pressure. The predetermined fluid pressure can be a relatively low pressure.

[0034] An accumulator 192, which may be formed as a cavity in the body of the PSU module 54, is connected to each of the second pump elements 185, 186 of the second pump 182. The PSU module 54 also includes a second noise damper 194 disposed between the outlet of each of the second pump elements 185, 186 and a corresponding one of the second interconnect passages 176, 178. Each of the second noise dampers 194 includes a restrictor orifice and a blow-off valve. The restrictor orifice is connected to the outlet of the corresponding one of the second pump elements 185, 186. The blow-off valve is in parallel with the restrictor orifice and is capable of restricting flow at low hydraulic flow conditions and not restricting hydraulic flow at high flow restriction. The PSU module 54 also has a second elastomer damper 195 connected to the outlet of each of the second pump elements 185, 186 of the second pump 182 to reduce pressure pulsing of the fluid supplied from the second pump elements and to further reduce noise.

[0035] The PSU module 54 also includes a second main pressure control valve 152 configured to control the flow of fluid between the second main interconnect passage 176 and the main bypass fluid passage 190. The second brake ECU 180 can send a control signal to the second main pressure control valve 152 to control the fluid pressure in the first main interconnect passage 76. The PSU module 54 also includes a second secondary pressure control valve 154 configured to control the flow of fluid between the second secondary interconnect passage 178 and the secondary bypass fluid passage 191. The second brake ECU 180 can send a control signal to the second main pressure control valve 152 to control the fluid pressure in the second secondary interconnect passage 178 and to control the fluid pressure in the first secondary interconnect passage 78 of the ESC module 52. The second pressure control valves 152, 154 can each be a normally open linear isolation valve with variable control of flow and / or pressure therethrough.

[0036] The PSU module 54 also includes a second pressure sensor 160 configured to monitor the fluid pressure in the second secondary interconnect passage 178. The second pressure sensor 160 is connected to a second brake ECU 180 for communicating the measured pressure.

[0037] As shown in Fig. 6, each of the rear wheel braking devices 22c, 22d has an electric parking brake EPB. The electric parking brake EPB of the right rear wheel braking device 22c is electrically connected to the second brake ECU 180. The electric parking brake EPB of the left rear wheel braking device 22d is electrically connected to the first brake ECU 80. This configuration provides redundancy for the electric parking brake EPB even if one of the brake ECUs 80, 180 loses power or becomes unusable. Alternatively or additionally, the front wheel braking devices 22a, 22b can have an electric parking brake EPB.

[0038] 7 shows a schematic diagram of the third braking system 150. The third braking system 150 can be similar or identical to the second braking system 50, except for the addition of isolation valves 156, 158 in the PSU module 54 to further improve flow control of the second pump 182. The isolation valves 156, 158 include a primary isolation valve 156 configured to control the flow of fluid between an outlet of the second primary pumping element 185 and the second primary interconnecting passage 176. The isolation valves 156, 158 also include a secondary isolation valve 158 configured to control the flow of fluid between an outlet of the second secondary pumping element 186 and the second secondary interconnecting passage 178. The isolation valves 156, 158 can each be a normally open linear isolation valve with variable control of flow therethrough. The second brake ECU 180 can send a control signal to each of the isolation valves 156, 158 to provide further flow control.

[0039] In one aspect of the present disclosure, a braking system for an automotive vehicle is provided, the braking system being operable in a normal brake-by-wire operating mode whereby the vehicle is slowed by an autopilot / automated driving device (AD ECU) controlling a primary electronic stability control assembly (ESC), and in a fallback mode whereby the ESC assembly fails whereby the vehicle is slowed by an autopilot / automated driving device controlling a secondary pressure supply unit assembly PSU.

[0040] The present invention provides a braking system for an automotive vehicle. The braking system includes an electronic stability control (ESC) module and a pressure supply unit (PSU) module. The electronic stability control (ESC) module has a first interconnection passage. The pressure supply unit (PSU) module has a second interconnection passage in fluid communication with the first interconnection passage of the ESC module. The ESC module has a first pump and a main valve. The first pump is configured to pump brake fluid from the PSU module to a plurality of wheel brakes. The main valve is configured to selectively control fluid communication between the first interconnection passage and an inlet of the first pump. The PSU module has a second pump and a bypass fluid passage. The second pump is configured to pump brake fluid from a fluid reservoir to the first interconnection passage of the ESC module. The bypass fluid passage has an in-line check valve. The bypass fluid passage is configured to route brake fluid from the fluid reservoir directly to the ESC module while bypassing the second pump. The in-line check valve is configured to allow fluid flow from the fluid reservoir to the ESC module through the bypass fluid passage while blocking fluid flow in the opposite direction.

[0041] In one embodiment, the ESC module and the PSU module each have two separate and independent braking circuits, the first pump and the second pump each having a primary pumping element and a secondary pumping element for pumping braking fluid through a corresponding one of the braking circuits.

[0042] In one embodiment, the main valve is a normally closed solenoid valve.

[0043] In one aspect, the ESC module further includes a supply fluid passage and at least one of an apply valve and a release valve. The supply fluid passage is configured to deliver brake fluid from the first pump to at least one wheel brake device of the plurality of wheel brake devices. The apply valve and at least one of the release valve control the flow of fluid between the supply fluid passage and the at least one wheel brake device.

[0044] In one aspect, the ESC module further comprises a pressure regulating valve configured to control fluid flow between the first interconnecting passageway and the supply fluid passageway of the ESC module to regulate fluid pressure.

[0045] In one embodiment, the pressure control valve is a normally open linear valve that allows variable control of flow therethrough.

[0046] In one aspect, the PSU module further includes a pressure control valve configured to control fluid flow between the second interconnect passage and the bypass fluid passage to regulate fluid pressure.

[0047] In one aspect, the pressure control valve is a normally open linear isolation valve.

[0048] In one embodiment, the PSU module further includes an isolation valve that controls fluid flow between the outlet of the second pump and the second interconnect passage.

[0049] In one embodiment, the isolation valve is a normally open linear valve that allows variable control of flow therethrough.

[0050] In one aspect, the ESC module and the PSU module each have an associated brake electronic control unit (ECU). Each brake ECU is separate and independent of each other. Each brake ECU has a corresponding power source. The power sources are separate and independent of each other.

[0051] The present invention also provides a braking system for an automotive vehicle. The braking system includes an electronic stability control (ESC) module and a PSU module. The ESC module has a first interconnection passage. The PSU module has a second interconnection passage in fluid communication with the first interconnection passage of the ESC module. The ESC module has a first electronic control unit (ECU) and a first pump. The first pump is configured to pump brake fluid from the PSU module to a plurality of wheel brakes. The PSU module has a second ECU, a second pump, and a bypass fluid passage. The second pump is configured to pump brake fluid from a fluid reservoir to the first interconnection passage of the ESC module. The bypass fluid passage includes an in-line check valve. The bypass fluid passage is configured to direct brake fluid from the fluid reservoir directly to the ESC module while bypassing the second pump. The in-line check valve is configured to allow fluid to flow from the fluid reservoir through the bypass fluid passage to the ESC module while blocking fluid flow in the opposite direction.

[0052] In one aspect, the braking system is configured to alternate application of multiple wheel brakes between the ESC module and the PSU module.

[0053] In one aspect, the ESC module further includes an isolation valve configured to selectively control fluid communication between the first interconnecting passage and the inlet of the first pump.

[0054] In one embodiment, the isolation valve is a normally open solenoid valve.

[0055] In one aspect, the first ECU is configured to control operation of the first pump. The second ECU is configured to control operation of the second pump. The braking system further includes an autonomous driving (AD) ECU in communication with each of the first ECU and the second ECU.

[0056] In one aspect, the AD ECU is configured to provide linear control regenerative braking for braking when the automotive vehicle is traveling at a speed greater than a predetermined speed.

[0057] In one aspect, the AD ECU is configured to operate one of the first pump and the second pump to supply brake fluid to a plurality of wheel brake devices for braking when the automotive vehicle is traveling at a speed lower than a predetermined speed.

[0058] In one aspect, the AD·ECU is configured to command a second ECU in the PSU module to supply brake fluid to the plurality of wheel brakes for braking when a fault condition is detected in the ESC module.

[0059] In one aspect, at least one of the first ECU and the second ECU is configured to implement at least one of an anti-lock braking system (ABS), an automatic emergency braking (AEB), and an electronic stability control (ESC) based on detected road conditions and / or instructions from an autonomous driving (AD) ECU.

[0060] In one embodiment, the ESC module and the PSU module may each be housed in a seemingly identical module to reduce manufacturing costs.

[0061] Of course, many variations and modifications of the present invention may be made in light of the above teachings and may be realized within the scope of the appended claims other than as specifically described herein, it being understood that the above description covers all combinations in which the novelty of the present invention is useful. [Explanation of symbols]

[0062] 10 Primary Braking System 20 Main EHCU 22a,22b Wheel braking device 22c,22d Wheel braking device (rear wheel braking device) 24 Fallback EHCU 50 Secondary Braking System 52 ESC module 54 PSU Module 56 EPB caliper 58 Fluid reservoir (reservoir) 60 Propulsion Subsystem 62 Autonomous Driving (AD) ECU 64 Steering Angle Sensor 70a~70d Wheel speed sensor 72 First Battery 74 Second Battery 76 First Main Interconnection Passage 77 Main Entrance 78 First secondary interconnecting passage 79 Side entrance 80 First brake ECU 82 First Pump 84 First Motor 85 Pump element 86 First auxiliary pump element 88 Main supply fluid passage 89 Sub-supply fluid passage 90 Main return fluid passage 91 Secondary return fluid passage 92 Accumulator 93 Return check valve 94 First Noise Damper 95 Elastomer Damper 96a Application valve 96b Release valve 100 Main Prime Valve (Prime Valve) 102 Sub-prime valve (prime valve) 104 First main pressure control valve (First pressure control valve) 106 First auxiliary pressure control valve (first pressure control valve) 108 First pressure sensor 150 Third Braking System 152 Second main pressure control valve (second pressure control valve) 154 Second auxiliary pressure control valve (Second pressure control valve) 156 Main isolation valve 158 Secondary isolation valve 160 Second pressure sensor 176 Second main interconnecting passage (Second interconnecting passage) 177 Main exit 178 Second secondary interconnecting passage (Second secondary interconnecting passage) 179 Secondary exit 180 Second ECU 182 Second Pump 184 Second Motor 185 Second main pump element (second pump element) 186 Second auxiliary pump element (second pump element) 188 Main reservoir fluid passage 189 Sub-reservoir fluid passage 190 Main bypass fluid passage 191 Secondary bypass fluid passage 192 Accumulator 193 In-line check valve 194 Second Noise Damper 195 Second elastomer damper

Claims

1. A braking system (50) for an automotive vehicle, comprising: an electronic stability control (ESC) module (52) having a first interconnection path (76, 78); a pressure supply unit (PSU) module (54) having a second interconnect passage (176, 178) in fluid communication with the first interconnect passage (76, 78) of the ESC module (52); Equipped with The ESC module (52) a first pump (82) configured to pump brake fluid from the PSU module (54) to a plurality of wheel brakes (22a, 22b, 22c, 22d); a prime valve (100, 102) configured to selectively control fluid communication between the first interconnecting passage (76, 78) and an inlet of the first pump (82); It has The PSU module (54) a second pump (182) configured to pump the brake fluid from a fluid reservoir (58) to the first interconnecting passages (76, 78) of the ESC module (52); a bypass fluid passage (190, 191) having an in-line check valve (193); It has the bypass fluid passage (190, 191) is configured to route the brake fluid directly from the fluid reservoir (58) to the ESC module (52) while bypassing the second pump (182); the in-line check valve (193) is configured to allow fluid flow from the fluid reservoir (58) through the bypass fluid passages (190, 191) to the ESC module (52) while blocking fluid flow in the opposite direction; The PSU module (54) further includes a pressure control valve (152, 154) configured to control fluid flow between the second interconnecting passage (176, 178) and the bypass fluid passage (190, 191) to control fluid pressure; The PSU module (54) further includes an isolation valve (156, 158) for controlling fluid flow between the outlet of the second pump (182) and the second interconnecting passage (176, 178); The isolation valves (156, 158) are normally open linear valves capable of variable control of flow therethrough. Braking system.

2. The ESC module (52) and the PSU module (54) each have two separate and independent braking circuits; the first pump (82) and the second pump (182) each have a primary pumping element (85, 185) and a secondary pumping element (86, 186) for pumping brake fluid through a corresponding one of the brake circuits; The braking system (50) of claim 1.

3. The prime valves (100, 102) are normally closed solenoid valves. A braking system (50) according to claim 1 or 2.

4. The ESC module (52) further comprises: a supply fluid passage (88) configured to deliver the brake fluid from the first pump (82) to at least one wheel brake device (22a, 22b, 22c, 22d) of the plurality of wheel brake devices (22a, 22b, 22c, 22d); at least one of an application valve (96a) and a release valve (96b) for controlling the flow of fluid between the supply fluid passage (88) and the at least one wheel braking device (22a, 22b, 22c, 22d); having A braking system (50) according to claim 1 or 2.

5. the ESC module (52) further comprising a pressure control valve (104, 106) configured to control fluid flow between the first interconnecting passage (76, 78) of the ESC module (52) and the supply fluid passage to control fluid pressure; In particular, the pressure control valves (104, 106) are normally open linear valves capable of variable control of flow therethrough. The braking system (50) of claim 4.

6. The pressure control valves (152, 154) are normally open linear isolation valves. A braking system (50) according to claim 1 or 2.

7. the ESC module (52) and the PSU module (54) each have an associated brake electronic control unit (ECU) (80, 180); The brake ECUs (80, 180) are separate and independent from each other, Each of the brake ECUs (80, 180) has a corresponding power source; The power sources are separate and independent of each other; A braking system (50) according to claim 1 or 2.

8. The ESC module (52) further includes a first electronic control unit (ECU) (80); The PSU module (54) further includes a second ECU (180). The braking system (50) of claim 1.

9. The braking system (50) is configured to alternate application of a plurality of wheel brakes (22a, 22b, 22c, 22d) between the ESC module (52) and the PSU module (54). The braking system (50) of claim 8.

10. the first ECU (80) is configured to control the operation of the first pump (82); the second ECU (180) is configured to control operation of the second pump (182); The braking system (50) further comprises: The first ECU (80) and an automatic driving (AD) ECU (62) communicating with each of the second ECUs (180); A braking system (50) according to claim 8 or 9.

11. The AD ECU (62) is configured to perform linear control regenerative braking when braking when the automobile vehicle is traveling at a speed higher than a predetermined speed. The braking system (50) of claim 10.

12. the AD ECU (62) is configured to operate one of the first pump (82) and the second pump (182) to supply the brake fluid to the plurality of wheel brake devices (22a, 22b, 22c, 22d) for braking when the automobile vehicle is traveling at a speed lower than a predetermined speed. The braking system (50) of claim 10.

13. the AD ECU (62) is configured to command the second ECU (180) of the PSU module (54) to supply the brake fluid to the plurality of wheel brake devices (22 a, 22 b, 22 c, 22 d) for braking when a fault condition is detected in the ESC module (52). The braking system (50) of claim 10.

14. At least one of the first ECU (80) and the second ECU (180) is configured to realize at least one of an anti-lock braking system (ABS), a dynamic rear proportioning (DRP) control of front and rear brake balance, an automatic emergency braking (AEB), and an electronic stability control (ESC) based on at least one of a detected road condition and an instruction from an automatic driving (AD) ECU (62). A braking system (50) according to claim 8 or 9.

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