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DE-102025145545-A1 - Fault-tolerant braking system with manual push-through on two wheels

DE102025145545A1DE 102025145545 A1DE102025145545 A1DE 102025145545A1DE-102025145545-A1

Abstract

A fault-tolerant braking system includes manual push-through at two wheels for selective actuation of a first and a second pair of wheel brakes. During manual push-through mode, a master cylinder can be selectively operated by actuating the brake pedal to generate a brake actuation pressure at at least one MC output to actuate the first pair of wheel brakes. During non-failure normal braking mode, a single-acting plunger (SAP) can be operated to generate a brake actuation pressure at a first and a second SAP output to hydraulically actuate the first and second pair of wheel brakes, respectively. A two-position three-way valve (2P3W valve) is hydraulically connected to the MC output, the first SAP output, and the first pair of wheel brakes. The 2P3W valve brings the front pair of wheel brakes into flow contact with the SAP in the non-failure normal braking mode and with the master cylinder in the manual push-through braking mode.

Inventors

  • Blaise J. Ganzel

Assignees

  • ZF Active Safety US Inc.

Dates

Publication Date
20260513
Application Date
20251105
Priority Date
20241112

Claims (20)

  1. Fault-tolerant braking system (100) with manual push-through on two wheels for selectively actuating a first and a second pair of wheel brakes (102), wherein the braking system (100) comprises: a reservoir (114); a master brake cylinder (104) that can be operated to provide a brake signal in response to actuation of an associated brake pedal, wherein, during a manual push-through mode, the master brake cylinder (104) can be selectively operated by actuation of the brake pedal to generate a brake actuation pressure at at least one MC output for hydraulically actuating the first pair of wheel brakes (102); a single-acting plunger (“SAP” - Single Acting Plunger) which, during a non-failure normal braking mode, can be operated by actuating an SAP electric motor to generate a brake actuation pressure at a first and a second SAP output for hydraulic actuation of the first and second pair of wheel brakes (102), respectively; a two-position three-way valve (“2P3W valve”) which is hydraulically connected to the MC output, the first SAP output, and the first pair of wheel brakes (102), wherein the 2P3W valve selectively controls the hydraulic fluid flow, as desired, from the master cylinder (104) or the SAP to a 2P3W valve output which is hydraulically connected to the first pair of wheel brakes (102); a secondary power transmission unit (“PTU”) configured to selectively supply pressurized hydraulic fluid to a first and a second PTU outlet for actuating the first and second pair of wheel brakes (102) in a non-failure normal braking mode and/or an auxiliary braking mode, wherein the secondary power transmission unit comprises a PTU electric motor configured to selectively pressurize the hydraulic fluid by transmitting a rotary motion to at least two pump pistons, each pump piston supplying pressurized hydraulic fluid to a corresponding first and second PTU outlet, the first and second PTU outlets supplying fluid to a corresponding first and second pair of wheel brakes (102); and an electronic control unit (“ECU”) that selectively controls the SAP and/or the secondary power transmission unit and/or the 2P3W valve in response to the brake signal; wherein the secondary power transmission unit and the SAP are fluid-connected to the reservoir (114); and whereby the 2P3W valve brings the first pair of wheel brakes (102) into fluid contact with the SAP in the non-failure normal braking mode and with the master brake cylinder (104) in the manual push-through braking mode.
  2. Braking system (100) according to Claim 1 , comprising a first traction control isovalve which is hydraulically arranged between the first pair of wheel brakes (102) and both the first SAP output and the MC output via the 2P3W valve; and a second traction control isoval which is hydraulically arranged directly between the second pair of wheel brakes (102) and the second SAP output.
  3. Braking system (100) according to Claim 2 , whereby the ECU selectively controls the first and second traction control isovalves.
  4. Braking system (100) according to one of the Claims 1 until 3 , comprising a brake pressure sensor hydraulically arranged along the 2P3W valve output, wherein the brake pressure sensor detects hydraulic pressure in the 2P3W valve output and generates a brake pressure signal in response thereto, wherein the ECU controls the SAP and/or the secondary power transmission unit and/or the 2P3W valve in response to the brake pressure signal.
  5. Braking system (100) according to one of the Claims 1 until 4 , comprising an iso/drain control valve arrangement assigned to each wheel brake of the first and second pair of wheel brakes (102), each iso/drain control valve arrangement being controlled by the electronic control unit.
  6. Braking system (100) according to Claim 5 , wherein each iso/drain control valve arrangement is optionally connected to the 2P3W valve outlet and/or the second SAP outlet to selectively receive pressurized hydraulic fluid from it.
  7. Braking system (100) according to Claim 5 or 6 , wherein the first traction control isovalve is hydraulically arranged between the 2P3W valve and the iso/drain control valve arrangements of the first pair of wheel brakes (102) and wherein the second traction control isovalve is hydraulically arranged between the second PTU outlet and the iso/drain control valve arrangements of the second pair of wheel brakes (102).
  8. Braking system (100) according to one of the preceding claims, comprising a pedal simulator in selective flow connection with the main brake cylinder (104) to provide predetermined feedback from the brake pedal.
  9. Braking system (100) according to Claim 8 , comprising a simulator valve which is hydraulically arranged between the pedal simulator and the reservoir (114) and/or the chamber of the master brake cylinder (104).
  10. Brake system (100) according to one of the preceding claims, wherein the 2P3W valve is double-wound and the electronic control unit is a first electronic control unit that selectively controls the 2P3W valve and the SAP, and the brake system (100) comprises a second electronic control unit that selectively controls the 2P3W valve and the secondary PTU, wherein the first and the second electronic control unit control the SAP and the secondary PTU respectively in response to the brake pressure signal.
  11. Braking system (100) according to Claim 10 , comprising a pedal simulator in selective flow connection with the master brake cylinder (104) to provide predetermined feedback of the brake pedal and a simulator valve hydraulically arranged between the pedal simulator and the reservoir (114) and/or the chamber of the master brake cylinder (104), wherein the simulator valve is double-wound and the first and second electronic control units selectively control the simulator valve.
  12. Braking system (100) according to Claim 10 or 11 , comprising an iso/drain control valve arrangement assigned to each wheel brake of the first and second pair of wheel brakes (102), wherein the second electronic control unit controls each of the iso/drain control valve arrangements.
  13. Braking system (100) according to one of the Claims 10 until 12 , with the second electronic control unit controlling the first and second traction control isovalves.
  14. Braking system (100) according to one of the preceding claims, wherein the first and the second SAP outlet, at least via a corresponding first or second traction control isovalve, are in flow communication with a pump outlet of at least one pump piston in order to selectively supply pressurized hydraulic fluid to it, wherein the secondary PTU in a non-failure normal braking mode and/or an auxiliary braking mode selectively increases the pressure of the pressurized hydraulic fluid from the SAP in order to supply at least one of the pair of wheel brakes (102) with hydraulic fluid at increased pressure.
  15. Brake system (100) according to one of the preceding claims, wherein the reservoir (114), the master brake cylinder (104) and the SAP are jointly positioned in a first housing and the secondary power transmission unit is positioned in a second housing spaced apart from the first housing.
  16. Brake system (100) according to one of the preceding claims, comprising an iso/drain control valve arrangement assigned to each wheel brake of the first and second pair of wheel brakes (102), wherein each iso/drain control valve arrangement is controlled by the electronic control unit; and wherein the reservoir (114), the master brake cylinder (104) and the SAP are jointly positioned in a first housing and the secondary power transmission unit and iso/drain control valve arrangements are positioned in a second housing spaced apart from the first housing.
  17. Brake system (100) according to one of the preceding claims, comprising a first filter hydraulically arranged between the master brake cylinder (104) and the 2P3W valve along the MC outlet, a second filter hydraulically arranged between the SAP and the 2P3W valve along the first SAP outlet, and a third filter hydraulically arranged between the SAP and the second traction control isovalve along the second SAP outlet, wherein the first, second and third filters restrict the movement of foreign bodies from the respective master brake cylinder (104) or SAP and into the 2P3W valve.
  18. Braking system (100) according to one of the preceding claims, comprising a pair of rear wheel brake motors for selectively electrically actuating a respective rear wheel brake.
  19. Braking system (100) according to one of the preceding claims, wherein it is a vertically divided system, wherein the first pair of wheel brakes (102) comprises a left and a right front wheel brake and the second pair of wheel brakes (102) comprises a left and a right rear wheel brake.
  20. Braking system (100) according to one of the preceding claims, wherein it is a diagonally divided system, wherein the first pair of wheel brakes (102) comprises a left front and a right rear wheel brake and the second pair of wheel brakes (102) comprises a right front and a left rear wheel brake.

Description

Technical field This disclosure relates to a device and a method for using a fault-tolerant braking system and in particular to methods and devices of a fault-tolerant braking system with manual push-through on two wheels. background This invention relates generally to vehicle braking systems. Vehicles are usually slowed down and stopped by hydraulic braking systems. These systems vary in complexity, but a basic braking system typically includes a brake pedal, a master cylinder, fluid lines that may be arranged in two similar but separate brake circuits, and wheel brakes in each circuit. The driver of the vehicle operates a brake pedal that is directly or indirectly connected to the master cylinder. When the brake pedal is depressed, the master cylinder generates hydraulic forces in both brake circuits by pressurizing the brake fluid. The pressurized fluid moves through the fluid lines in both circuits to actuate brake cylinders at the wheels, thus slowing the vehicle. Basic braking systems generally use a brake booster that supplies force to the master cylinder to assist the pedal force applied by the driver. The power from the amplifier assists the pedal force acting on the pistons of the master brake cylinder, which generate pressurized fluid in the line that is in flow communication with the wheel brakes. During the initial movement of the brake pedal assembly in boost mode, the driver presses the brake pedal, causing an initial movement of an input piston in the master cylinder. Further movement of the input piston pressurizes the master cylinder's inlet chamber, causing fluid to flow into a pedal simulator. As fluid is diverted into the pedal simulator, a simulation pressure chamber within the simulator expands, causing a piston within the simulator to move. This piston movement compresses a spring assembly housed within the pedal simulator, pre-tensioning the piston to provide feedback to the driver through the brake pedal. This feedback simulates the forces a driver would feel at the brake pedal in, for example, a conventional vacuum-assisted hydraulic braking system, thus providing an expected and reassuring "braking feel" for the driver. Descriptions of state-of-the-art braking systems are contained in the permit issued to Blaise Ganzel on August 4, 2020. US Patent No. 10,730,501 with the title “ Vehicle Brake System with Auxiliary Pressure Source”, in October 1, 2020 US patent application published by Blaise Ganzel, publication no. 1260/0307538 with the title “ Brake System with Multiple Pressure Sources” and the one on August 12, 2021 v on Blaise Ganzel's US patent application with the file number. 17/400,250 with the title “ Apparatus and Method for Control of a Hydraulic Brake System Including Manual Pushthrough “, whose contents are hereby referenced in their entirety for all purposes. The object of the invention is to overcome the disadvantages of the prior art, in particular to provide a braking system that improves vehicle safety. This object is achieved by the subject matter of the independent claims, with optional further developments specified in the dependent claims. Brief description In one aspect, alone or in combination with another aspect, a fault-tolerant braking system with manual push-through at two wheels is provided for the selective actuation of a first and a second pair of wheel brakes. The system includes a reservoir and a master cylinder (MC) that can be operated to provide a braking signal in response to the actuation of an associated brake pedal. During a manual push-through mode, the master cylinder can be selectively operated by actuating the brake pedal to generate a brake actuation pressure at at least one MC output for the hydraulic actuation of the first pair of wheel brakes. During a non-failure normal braking mode, a single-acting plunger (SAP) can be operated by actuating an SAP electric motor to generate a brake actuation pressure at a first and a second SAP output for the hydraulic actuation of the first and second pair of wheel brakes, respectively. A two-position three-way valve (“2P3W valve”) is hydraulically connected to the MC output, the first SAP output, and the first pair of wheel brakes. The 2P3W valve selectively controls the hydraulic fluid flow, depending on the selection, from the master cylinder or the SAP to a 2P3W valve output connected to the first wheel brake. The first and second pairs of wheel brakes are hydraulically connected. A secondary power transmission unit (PTU, or secondary brake module) is configured to selectively supply pressurized hydraulic fluid to the first and second PTU outlets, respectively, to actuate the first and second pairs of wheel brakes in a non-failure normal braking mode and/or an auxiliary braking mode. The secondary power transmission unit includes a PTU electric motor configured to selectively pressurize the hydraulic fluid by transmitting a rotary motion to at least two pump pistons. Each pump piston supplies