Patent Description:
Autonomous vehicles need to provide braking without driver input. Typically, these solutions are provided by one box braking system that provide brake apply (actuation) and brake modulation (ABS/ESC) all architected within one hardware box. An additional brake unit is either integrated within the one box or added separately to provide redundancy for brake apply and possibly for the brake modulation (ABS/ESC). These types of systems are very capable but can be quite expensive. One example belonging to the state of the art is disclosed by <CIT> which shows a brake system for a motor vehicle, comprising an electronic stability control module with a first interconnect passage and a pressure supply unit module with a second interconnect passage in fluid communication with the first interconnect passage of the ESC module; the PSU module includes a second pump configured to transfer the brake fluid from a fluid reservoir to the first interconnect passage of the ESC module and a bypass fluid passage with an inline check valve.

The present invention provides a brake system for a motor vehicle. The brake system comprises two brake related modules, an electronic stability control (ESC) module defining a first interconnect passage, and a pressure supply unit (PSU) module defining a second interconnect passage in fluid communication with the first interconnect passage of the ESC module. The ESC module includes a first pump configured to transfer brake fluid from the PSU module and to a plurality of wheel brakes, and a prime valve configured to selectively control fluid communication between the first interconnect passage and an inlet of the first pump. The PSU module includes a second pump configured to transfer the brake fluid from a fluid reservoir to the first interconnect passage of the ESC module, and a bypass fluid passage with an inline check valve. The bypass fluid passage is configured to convey the brake fluid directly from the fluid reservoir to the ESC module and to bypass the second pump. The inline check valve is configured to allow fluid flow through the bypass fluid passage from the fluid reservoir and to the ESC module while blocking fluid flow in an opposite direction.

The present invention also provides a brake system for a motor vehicle. The brake system comprises an electronic stability control (ESC) module defining a first interconnect passage, and a pressure supply unit (PSU) module defining a second interconnect passage in fluid communication with the first interconnect passage of the ESC module. The ESC module includes a first electronic control unit (ECU) and a first pump configured to transfer brake fluid from the PSU module and to a plurality of wheel brakes. The PSU module includes a second ECU and a second pump configured to transfer the brake fluid from a fluid reservoir to the first interconnect passage of the ESC module, and a bypass fluid passage with an inline check valve. The bypass fluid passage is configured to convey the brake fluid directly from the fluid reservoir to the ESC module and bypassing the second pump. The inline check valve is configured to allow fluid flow through the bypass fluid passage from the fluid reservoir and to the ESC module while blocking fluid flow in an opposite direction.

Referring to the drawings, the present invention will be described in detail in view of following embodiments.

The system of the present invention may be suitable for Level <NUM> or greater automation based on the "Levels of Driving Automation" standard by SAE International that defines six levels of driving automation, as specified in SAE standard J3016. Level <NUM> automation provides for a vehicle to be fully autonomous (i.e., no driver required) but may be restricted to speed and area of operation. This type of vehicle may include a shuttle that moves around in a prescribed area at some maximum speed carrying either passengers or packages.

The brake systems of the present invention may interact with an autonomous driving controller and software stack which may command via CAN messaging or alternate bus messaging to the braking units to perform the level of braking as required.

The present invention provides for service braking to be performed by two off the shelf Electronic Stability Control (ESC) units, with one so modified as to become a specialized Pressure Supply Unit (PSU), architected in a fashion to provide redundancy. An additional benefit also provided in this dual module approach is distributed EPB (Electric Park Brake) control that also provides continued EPB functionality in the event of an ECU (electronic control unit) failure that drives the electric park brakes.

The brake systems of the present invention may include one completely standard <NUM>-valve ESC unit and one PSU unit to provide both redundant brake actuation and to provide standard ABS/ESC within an economical two box package. Actuation 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 brake actuation. In some embodiments, the typical brake actuation functions alternate between each unit on each brake apply. This would allow the wear of the units to be spread evenly between them.

<FIG> shows a schematic diagram of a first brake system <NUM> according to an aspect of the present invention. The first brake system <NUM> is configured to provide redundant braking operation which is required for Level <NUM> or greater automation. The first brake system <NUM> includes a primary Electric-Hydraulic Control Unit (EHCU) <NUM> hydraulically connected to four wheel brakes 22a, 22b, 22c, 22d. The primary EHCU <NUM> may be a full-function device, including ability to generate fluid pressure for applying each of the wheel brakes 22a, 22b, 22c, 22d and for controlling distribution of the fluid to provide functions such as anti-lock braking, electronic stability control, etc. The wheel brakes 22a, 22b, 22c, 22d may each be connected to a corresponding wheel (not shown) of a vehicle and may also be called foundation brakes for function in stopping the vehicle. A fallback EHCU <NUM> is hydraulically coupled to the primary EHCU <NUM> to provide fluid for operating the wheel brakes 22a, 22b, 22c, 22d in case the primary EHCU <NUM> is unavailable. The fallback EHCU <NUM> is also in communication with the primary EHCU <NUM> via a Controller Area Network (CAN) interconnection <NUM>. However, other communications interfaces may be used.

The first brake system <NUM> could work well but the cost of the primary EHCU <NUM> is very high due to the incorporation of such components as a brushless motor, ball screw, and corresponding controls needed to make the system function correctly. This type of unit has very fast response time, which in many cases for some Level <NUM> applications where speed limits are constrained, that are much faster than required.

<FIG> shows a schematic diagram of a second brake system <NUM> according to an aspect of the present invention. The second brake system <NUM> is also configured to provide redundant braking operation which is required for Level <NUM> or greater automation. The second brake system <NUM> may provide cost advantages over the first brake system <NUM>. The second brake system <NUM> includes an electronic stability Control (ESC) module <NUM> and a PSU module <NUM> that is packaged similar to the ESC module <NUM> and shares common components. The ESC module <NUM> and the PSU module <NUM> may be derived from a same basic ESC design package to save manufacturing costs. The ESC module <NUM> may be a fully functional ESC, while the PSU module <NUM> may be primarily used for fallback and base brake applies. If autonomous braking is required at any speed, either one of the modules <NUM>, <NUM> can provide the braking. The reservoir <NUM> stores fluid to be used directly by the PSU module <NUM> or indirectly by the ESC module <NUM>.

Each of the modules <NUM>, <NUM> may include a pump driven by an electric motor and one or more solenoid valves to control distribution of pressurized fluid for operating the wheel brakes 22a, 22b, 22c, 22d. The ESC module <NUM> and PSU module <NUM> may be configured as an integrated package including the pump and corresponding motor, an electronic control unit (ECU), and a hydraulic control unit (HCU) including the valves with associated fluid passages and hydraulic fittings for distributing brake fluid to operate the wheel brakes 22a, 22b, 22c, 22d. The ESC <NUM> module and the PSU module <NUM> may be housed in nearly identical appearing modules such as a DBC <NUM> ESC device. The second brake system <NUM> may also utilize regenerative braking, particularly at higher speeds.

The second brake system <NUM> also includes two rear wheel brakes 22c, 22d of the wheel brakes 22a, 22b, 22c, 22d configured with an electric parking brake (EPB) caliper <NUM>. Such EPB calipers <NUM> each include an electric actuator that is configured to apply the brake, in addition to or instead of by hydraulic application. In other words, each of the EPB calipers <NUM> may provide braking force in response to either or both of an electrical signal and/or a hydraulic brake pressure supply. Alternatively or additionally, the two front wheel brakes 22c, 22d of the wheel brakes 22a, 22b, 22c, 22d may be configured with EPB calipers <NUM>. In some embodiments, each the of the ESC modules <NUM>, <NUM> may be configured to control one or more of the EPB calipers <NUM>. For example, the ECU in module <NUM> may control one of the two EPB calipers <NUM> in the right rear wheel brake 22c and the ECU in module <NUM> may control the other EPB caliper <NUM> in the left rear wheel brake 22d. Such a configuration may provide enhanced safety and/or redundancy in case of ECU failure.

<FIG> shows a schematic block diagram showing functional interconnections between vehicle systems including the second brake system <NUM>. <FIG> shows a vehicle that includes a propulsion subsystem <NUM> that may also provide regenerative (regen) braking functions. The propulsion subsystem <NUM> may include one or more electric machines, such as motor/generators. The propulsion subsystem <NUM> may include other associated devices, such as inverters, electronic control units, batteries, etc. <FIG> also shows an Autonomous Driving (AD) electronic control unit (ECU) <NUM> that provides an AD stack in functional communication with each of the propulsion subsystem <NUM> and the second brake system <NUM>. The AD ECU <NUM> may include hardware and/or software configured to coordinate autonomous driving functions of the vehicle. The AD ECU <NUM> may be in charge of propulsion and braking. The AD ECU <NUM> may control regenerative braking, which may include a majority of the braking above a predetermined speed. Below the predetermined speed, the ECUs <NUM>, <NUM> of the ESC modules <NUM>, <NUM> of the second brake system <NUM> may control braking to a standstill.

The ESC module <NUM> and PSU module <NUM> of the second brake system <NUM> may be actuated to slow the vehicle or bring the vehicle to a standstill condition and may function as follows:.

The ESC module <NUM> and PSU module <NUM> each include a corresponding brake modulator. Either or both of the brake modulators can apply the wheel brakes 22a, 22b, 22c, 22d to provide redundant braking. The brake modulator may include a pump to provide brake fluid for applying the wheel brakes 22a, 22b, 22c, 22d. The ESC module <NUM> and PSU module <NUM> may alternate brake apply duties to balance wear therebetween. In some embodiments, automatic emergency braking (AEB), anti-lock brakes (ABS), Dynamic Rear Proportioning (DRP) used to maintain front to rear brake balance, and/or electronic stability control (ESC) functions may be handled by either the ESC module <NUM> or the PSU module <NUM>. The runtime of the pumps in the ESC module <NUM> and PSU module <NUM> may be recorded and reported for maintenance.

<FIG> shows a schematic block diagram showing hydraulic interconnections of the second brake system <NUM>. As shown in <FIG>, each of the wheel brakes 22a, 22b, 22c, 22d is connected to a corresponding wheel 23a-23d for applying a braking force thereto. A fluid reservoir <NUM> is connected to the PSU module <NUM> for supplying brake fluid thereto.

As also shown on <FIG>, each of the rear wheel brakes 22c, 22d includes an electric parking brake EPB. The electric parking brake EPB of the right-rear wheel brake 22c is electrically connected to the second brake ECU <NUM>, and the electric parking brake EPB of the left-rear wheel brake 22d is electrically connected to the first brake ECU <NUM>. This arrangement provides redundancy for the electric parking brakes EPB in case either of the brake ECUs <NUM>, <NUM> loses power or is otherwise unavailable.

<FIG> shows a schematic block diagram showing electrical interconnections of the second brake system <NUM>. As shown in <FIG>, each of the wheels 23a-23d is connected to a corresponding wheel speed sensor 70a-70d for measuring a rotational speed of the wheels. The front wheel speed sensors 70a, 70b are connected to the first brake ECU <NUM>. The rear wheel speed sensors 70c, 70d are connected to the second brake ECU <NUM>. This arrangement provides redundancy for the wheel speed sensors 70a, 70b, and 70c, 70d in case either of the brake ECUs <NUM>, <NUM> loses power or is otherwise unavailable. The first brake ECU <NUM> and the second brake ECU <NUM> are both functionally connected to the AD ECU <NUM>. A first power source, such as a first battery <NUM>, is connected to the ESC module <NUM> for providing backup power thereto, and a second power source, such as a second battery <NUM>, is connected to the PSU module <NUM> for providing backup power thereto. In this way, the ESC module <NUM> and the PSU module <NUM> each has a separate and independent backup power supply.

<FIG> shows a schematic diagram of the second brake system <NUM>, showing details of each of the ESC module <NUM> and the PSU module <NUM> and their interconnections. Each of the modules has two separate and independent brake circuits, with associated components designated as primary and secondary. The separate and independent brake circuits may each be operated under normal conditions and may provide redundancy. For example, either of the brake circuits may provide braking function even in case of a major failure, such as a large fluid leak, in the other one of the brake circuits.

As shown in <FIG>, the ESC module <NUM> includes a first primary interconnect passage <NUM> with a corresponding primary inlet port <NUM>, and a first secondary interconnect passage <NUM> with a corresponding secondary inlet port <NUM>. The ESC module <NUM> also includes a first brake ECU <NUM> and a first pump <NUM> having a first motor <NUM> controlled by the first brake ECU <NUM>. For example, the first brake ECU <NUM> may supply a control power, such as a pulse-width-modulated (PWM) alternating current power to the first motor <NUM> for controlling a speed of the first motor <NUM>. The first pump <NUM> also includes a first primary pump element <NUM> and a first secondary pump element <NUM> each coupled to the first motor <NUM> for supplying fluid through the corresponding brake circuit. A steering angle sensor <NUM> is in functional communication with the first brake ECU <NUM> to communicate steering angle data thereto. The first brake ECU <NUM> may use the steering angle data and/or other vehicle data for adjusting one or more parameters related to operation of the brakes.

The ESC module <NUM> includes a primary supply fluid passage <NUM> configured to convey fluid from the first primary pump element <NUM> of the first pump <NUM> to two of the wheel brakes 22a, 22b. The ESC module <NUM> also includes a secondary supply fluid passage <NUM> configured to convey fluid from the first secondary pump element <NUM> of the first pump <NUM> to the other two of the wheel brakes 22c, 22d. The ESC module <NUM> includes a primary return fluid passage <NUM> configured to convey fluid from the corresponding wheel brakes 22a, 22b and to the first primary pump element <NUM> of the first pump <NUM>. The ESC module <NUM> also includes a secondary return fluid passage <NUM> configured to convey fluid from the corresponding wheel brakes 22c, 22d and to the first secondary pump element <NUM> of the first pump <NUM>.

An accumulator <NUM> is coupled to each of the return fluid passages <NUM>, <NUM> for holding fluid from the corresponding ones of the wheel brakes 22a, 22b, 22c, 22d and supplying the fluid to the corresponding pump elements <NUM>, <NUM>. Each of the accumulators <NUM> may include a piston that is displaceable in a bore and biased by a spring to hold the fluid therein. However, either or both of the accumulators <NUM> may have a different configuration. A return check valve <NUM> is disposed between each of the each of the return fluid passages <NUM>, <NUM> and the corresponding one of the first pump elements <NUM>, <NUM> for allowing fluid flow from the return fluid passage <NUM>, <NUM> to the corresponding one of the first pump elements <NUM>, <NUM> while blocking fluid flow in an opposite direction.

The ESC module <NUM> also includes a first noise damper <NUM> disposed between an outlet of each of the first pump elements <NUM>, <NUM> and the corresponding supply fluid passage <NUM>, <NUM>. Each of the first noise dampers <NUM> includes a restrictor orifice connected to the outlet of the corresponding first pump element <NUM>, <NUM>, and a blow-off valve in parallel with the restrictor orifice to permit flow restrictions at low hydraulic flow conditions and unrestricted hydraulic flow at high flow restriction. The ESC module <NUM> also includes an elastomeric damper <NUM> connected to the outlet of each of the first pump element <NUM>, <NUM> to reduce pulsing in the pressure of the fluid supplied therefrom and to further reduce noise.

The ESC module <NUM> includes an apply valve 96a and a relief valve 96b associated with each of the wheel brakes 22a, 22b, 22c, 22d for controlling fluid flow to and from the wheel brakes 22a, 22b, 22c, 22d. The apply valves 96a are each configured to control fluid flow from a corresponding one of the supply fluid passages <NUM>, <NUM> and to a corresponding one of the wheel brakes 22a, 22b, 22c, 22d. The relief valves 96b are each configured to control fluid flow from a corresponding one of the wheel brakes 22a, 22b, 22c, 22d and to a corresponding one of the supply fluid passages <NUM>, <NUM> and to a corresponding one of the return fluid passages <NUM>, <NUM>.

The ESC module <NUM> also includes a primary prime valve <NUM> that is configured to selectively control fluid communication between the first primary interconnect passage <NUM> and the inlet of the first primary pump element <NUM> of the first pump <NUM>. The ESC module <NUM> also includes a secondary prime valve <NUM> that is configured to selectively control fluid communication between the first secondary interconnect passage <NUM> and the inlet of the first secondary pump element <NUM> of the first pump <NUM>. Each of the prime valves <NUM>, <NUM> may be normally-closed solenoid valves.

The ESC module <NUM> also includes a first primary pressure control valve <NUM> that is hydraulically connected between the between the first primary interconnect passage <NUM> and the primary supply fluid passage <NUM> for regulating a fluid pressure in the first primary interconnect passage <NUM>. The ESC module <NUM> also includes a first secondary pressure control valve <NUM> that is hydraulically connected between the between the first secondary interconnect passage <NUM> and the secondary supply fluid passage <NUM> for regulating a fluid pressure in the first secondary interconnect passage <NUM>. Each of the first pressure control valves <NUM>, <NUM> may be a normally-open linear isolation valve that is capable of variable control of pressure thereacross. The ESC module <NUM> also includes a first pressure sensor <NUM> that is configured to monitor a fluid pressure in the first primary interconnect passage <NUM> and which is connected to the first brake ECU <NUM> for communicating the measured pressure thereto.

As shown in <FIG>, the PSU module <NUM> includes a second primary interconnect passage <NUM> with a corresponding primary outlet port <NUM> that is fluidly coupled to the primary inlet port <NUM> of the ESC module <NUM> for supplying fluid thereto. The PSU module <NUM> also includes a second secondary interconnect passage <NUM> with a corresponding secondary outlet port <NUM> that is fluidly coupled to the secondary inlet port <NUM> of the PSU module <NUM> for supplying fluid thereto. The PSU module <NUM> also includes a second brake ECU <NUM> and a second pump <NUM> having a second motor <NUM> controlled by the second brake ECU <NUM>. For example, the second brake ECU <NUM> may supply a control power, such as a pulse-width-modulated (PWM) alternating current power to the second motor <NUM> for controlling a speed of the second motor <NUM>. The second pump <NUM> also includes a second primary pump element <NUM> and a second secondary pump element <NUM> each coupled to the second motor <NUM> for supplying fluid through a corresponding brake circuit. The second primary pump element <NUM> is configured to transfer brake fluid from the fluid reservoir <NUM> to first primary interconnect passage <NUM> of the ESC module <NUM> via the second primary interconnect passage <NUM>. The second secondary pump element <NUM> is configured to transfer brake fluid from the fluid reservoir <NUM> to the first secondary interconnect passage <NUM> of the ESC module <NUM> via the second secondary interconnect passage <NUM>.

The PSU module <NUM> includes a primary reservoir fluid passage <NUM> configured to convey fluid from the fluid reservoir <NUM> to the second primary pump element <NUM> of the second pump <NUM> via a primary reservoir port Rp. The PSU module <NUM> also includes a secondary reservoir fluid passage <NUM> configured to convey fluid from the fluid reservoir <NUM> to the second secondary pump element <NUM> of the second pump <NUM> via a secondary reservoir port Rs. The PSU module <NUM> includes a primary bypass fluid passage <NUM> providing fluid communication between the primary reservoir fluid passage <NUM> and the second primary interconnect passage <NUM> for conveying brake fluid directly from the fluid reservoir <NUM> to the ESC module <NUM> and bypassing the second pump <NUM>. The PSU module <NUM> includes a secondary bypass fluid passage <NUM> providing fluid communication between the secondary reservoir fluid passage <NUM> and the second secondary interconnect passage <NUM> for conveying brake fluid directly from the fluid reservoir <NUM> to the ESC module <NUM> and bypassing the second pump <NUM>. An inline check valve <NUM> is located in a fluid path between each of the second interconnect passages <NUM>, <NUM> and a corresponding one of the bypass fluid passages <NUM>, <NUM>. Each of the inline check valves <NUM> is configured to allow fluid flow through the corresponding one of the bypass fluid passages <NUM>, <NUM> from the fluid reservoir <NUM> and to the ESC module <NUM> via a corresponding one of the second interconnect passages <NUM>, <NUM>, while blocking fluid flow in an opposite direction. Each of the inline check valves <NUM> may have a low blow-off pressure allowing fluid flow therethrough only with predetermined fluid pressure thereacross, which may be a relatively low pressure.

An accumulator <NUM>, which may be formed as a cavity in a body of the PSU module <NUM>, is coupled to each of the second pump elements <NUM>, <NUM> of the second pump <NUM>. The PSU module <NUM> also includes a second noise damper <NUM> disposed between an outlet of each of the second pump elements <NUM>, <NUM> and the corresponding one of the second interconnect passages <NUM>, <NUM>. Each of the second noise dampers <NUM> includes a restrictor orifice connected to the outlet of the corresponding one of the second pump elements <NUM>, <NUM>, and a blow-off valve in parallel with the restrictor orifice to permit flow restrictions at low hydraulic flow conditions and unrestricted hydraulic flow at high flow restriction. The PSU module <NUM> also includes a second elastomeric damper <NUM> connected to the outlet of each of the second pump elements <NUM>, <NUM> of the second pump <NUM> to reduce pulsing in the pressure of the fluid supplied therefrom and to further reduce noise.

The PSU module <NUM> also includes a second primary pressure control valve <NUM> controlling fluid flow between the second primary interconnect passage <NUM> and the primary bypass fluid passage <NUM>. The second brake ECU <NUM> may supply a control signal to the second primary pressure control valve <NUM> to regulate a fluid pressure in the first primary interconnect passage <NUM>. The PSU module <NUM> also includes a second secondary pressure control valve <NUM> controlling fluid flow between the second secondary interconnect passage <NUM> and the secondary bypass fluid passage <NUM>. The second brake ECU <NUM> may supply a control signal to the second primary pressure control valve <NUM> to regulate a fluid pressure in the second secondary interconnect passage <NUM> and to thereby also regulate the fluid pressure in the first secondary interconnect passage <NUM> of the ESC module <NUM>. Each of the second pressure control valves <NUM>, <NUM> may be a normally-open linear isolation valve that is capable of variable control of flow therethrough and/or pressure thereacross.

The PSU module <NUM> also includes a second pressure sensor <NUM> that is configured to monitor a fluid pressure in the second secondary interconnect passage <NUM> and which is connected to the second brake ECU <NUM> for communicating the measured pressure thereto.

As also shown on <FIG>, each of the rear wheel brakes 22c, 22d includes an electric parking brake EPB. The electric parking brake EPB of the right-rear wheel brake 22c is electrically connected to the second brake ECU <NUM>, and the electric parking brake EPB of the left-rear wheel brake 22d is electrically connected to the first brake ECU <NUM>. This arrangement provides redundancy for the electric parking brakes EPB in case either of the brake ECUs <NUM>, <NUM> loses power or is otherwise unavailable. Alternatively, or additionally, the front wheel brakes 22a, 22b may include electric parking brakes EPB.

<FIG> shows a schematic diagram of a third brake system <NUM>. The third brake system <NUM> may be similar or identical to the second brake system <NUM>, but with the addition of isolation valves <NUM>, <NUM> in the PSU module <NUM> to further improve flow control of the second pump <NUM>. The isolation valves <NUM>, <NUM> include a primary isolation valve <NUM> configured to control fluid flow between the outlet of the second primary pump element <NUM> and the second primary interconnect passage <NUM>. The isolation valves <NUM>, <NUM> also include a secondary isolation valve <NUM> configured to control fluid flow between the outlet of the second secondary pump element <NUM> and the second secondary interconnect passage <NUM>. Each of the isolation valves <NUM>, <NUM> may be a normally-open linear isolation valve that is capable of variable control of flow therethrough. The second brake ECU <NUM> may supply a control signal to each of the isolation valves <NUM>, <NUM> to provide additional flow control.

According to an aspect of the invention, a brake system for motor vehicles is provided. The brake system can be activated in a normal brake-by-wire operating mode to slow the vehicle by an auto-pilot/autonomous driving device (AD ECU) controlling a primary electronic stability control assembly (ESC) and the same brake system in a fallback mode with a failed ESC assembly can be activated to slow the vehicle by an auto-pilot/autonomous driving device controlling a secondary pressure supply unit assembly PSU.

The present invention provides a brake system for a motor vehicle. The brake system comprises an electronic stability control (ESC) module defining a first interconnect passage, and a pressure supply unit (PSU) module defining a second interconnect passage in fluid communication with the first interconnect passage of the ESC module. The ESC module includes a first pump configured to transfer brake fluid from the PSU module and to a plurality of wheel brakes, and a prime valve configured to selectively control fluid communication between the first interconnect passage and an inlet of the first pump. The PSU module includes a second pump configured to transfer the brake fluid from a fluid reservoir to the first interconnect passage of the ESC module, and a bypass fluid passage with an inline check valve. The bypass fluid passage is configured to convey the brake fluid directly from the fluid reservoir to the ESC module and to bypass the second pump. The inline check valve is configured to allow fluid flow through the bypass fluid passage from the fluid reservoir and to the ESC module while blocking fluid flow in an opposite direction.

In some embodiments, each of the ESC module and the PSU module includes two separate and independent brake circuits, with each of the first pump and the second pump including a primary pump element and a secondary pump element for pumping brake fluid through a corresponding one of the brake circuits.

In some embodiments, the prime valve is a normally-closed solenoid valve.

In some embodiments, the ESC module further includes a supply fluid passage configured to convey the brake fluid from the first pump to at least one wheel brake of the plurality of wheel brakes, and at least one of an apply valve and a release valve for controlling fluid flow between the supply fluid passage and the at least one wheel brake.

In some embodiments, the ESC module further includes a pressure control valve configured to control a fluid flow between the first interconnect passage of the ESC module and the supply fluid passage for regulating a fluid pressure.

In some embodiments, the pressure control valve is a normally-open linear valve capable of variable control of flow therethrough.

In some embodiments, the PSU module further includes a pressure control valve controlling fluid flow between the second interconnect passage and the bypass fluid passage for regulating a fluid pressure.

In some embodiments, the pressure control valve is a normally-open linear isolation valve.

In some embodiments, the PSU module further includes an isolation valve controlling fluid flow between and outlet of the second pump and the second interconnect passage.

In some embodiments, the isolation valve is a normally-open linear valve capable of variable control of flow therethrough.

In some embodiments, each of the ESC module and the PSU module has an associated brake electronic control unit (ECU), with each of the brake ECUs being separate and independent, and each of the brake ECUs has a corresponding power supply, with the power supplies being separate and independent from one another.

The present invention also provides a brake system for a motor vehicle. The brake system comprises an electronic stability control (ESC) module defining a first interconnect passage, and a PSU module defining a second interconnect passage in fluid communication with the first interconnect passage of the ESC module. The ESC module includes a first electronic control unit (ECU) and a first pump configured to transfer brake fluid from the PSU module and to a plurality of wheel brakes. The PSU module includes a second ECU and a second pump configured to transfer the brake fluid from a fluid reservoir to the first interconnect passage of the ESC module, and a bypass fluid passage with an inline check valve. The bypass fluid passage is configured to convey the brake fluid directly from the fluid reservoir to the ESC module and bypassing the second pump. The inline check valve is configured to allow fluid flow through the bypass fluid passage from the fluid reservoir and to the ESC module while blocking fluid flow in an opposite direction.

In some embodiments, the brake system is configured to alternate applications of the plurality of wheel brakes between the ESC module and the PSU module.

In some embodiments, the ESC module further includes an isolation valve configured to selectively control fluid communication between the first interconnect passage and an inlet of the first pump.

In some embodiments, the isolation valve is a normally-open solenoid valve.

In some embodiments, the first ECU is configured to control operation of the first pump, and the second ECU is configured to control operation of the second pump, and the brake system further comprises an autonomous driving (AD) ECU in communication with each of the first ECU and the second ECU.

In some embodiments, the AD ECU is configured to utilize linearly controlled regenerative braking for braking events with the motor vehicle traveling greater a given speed.

In some embodiments, the AD ECU is configured to activate one of the first pump or the second pump to supply the brake fluid to the plurality of wheel brakes for braking events and with the motor vehicle traveling below a given speed.

In some embodiments, the AD ECU is configured to command the second ECU of the PSU module to supply the brake fluid to the plurality of wheel brakes for braking events and in response to a faulted condition being detected in the ESC module.

In some embodiments, at least one of the first ECU or the second ECU is configured to implement at least one of: an anti-lock braking system (ABS), autonomous emergency braking (AEB), and electronic stability control (ESC) based on at least one of a detected surface condition and a command from an autonomous driving (AD) ECU.

In some embodiments, to save manufacturing costs, the ESC module and the PSU module may be housed in identical appearing modules.

Claim 1:
A brake system (<NUM>) for a motor vehicle, comprising:
an electronic stability control (ESC) module (<NUM>) defining a first interconnect passage (<NUM>, <NUM>), and a pressure supply unit (PSU) module (<NUM>) defining a second interconnect passage (<NUM>, <NUM>) in fluid communication with the first interconnect passage (<NUM>, <NUM>) of the ESC module (<NUM>);
the ESC module (<NUM>) including a first pump (<NUM>) configured to transfer brake fluid from the PSU module (<NUM>) and to a plurality of wheel brakes (22a, 22b, 22c, 22d), and a prime valve (<NUM>, <NUM>) configured to selectively control fluid communication between the first interconnect passage (<NUM>, <NUM>) and an inlet of the first pump (<NUM>);
the PSU module (<NUM>) including a second pump (<NUM>) configured to transfer the brake fluid from a fluid reservoir (<NUM>) to the first interconnect passage (<NUM>, <NUM>) of the ESC module (<NUM>), and a bypass fluid passage (<NUM>, <NUM>) with an inline check valve (<NUM>);
wherein the bypass fluid passage (<NUM>, <NUM>) is configured to convey the brake fluid directly from the fluid reservoir (<NUM>) to the ESC module (<NUM>) and bypassing the second pump (<NUM>); and
wherein the inline check valve (<NUM>) is configured to allow fluid flow through the bypass fluid passage (<NUM>, <NUM>) from the fluid reservoir (<NUM>) and to the ESC module (<NUM>) while blocking fluid flow in an opposite direction.