Trailer brake control system

Inventors: Philipp Kirmaier (Marktoberdorf, DE); Georg Frank (Marktoberdorf, DE)

Assignee: AGCO International GmbH

B60T13/683 B60T7/20 B60T8/1701 B60T8/3605 B60T13/268 B60T13/581 B60T17/22 B60T2270/88

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Quick Facts

Patent No.: US 12668225
App. No.: 18/253,812
Granted: Jun 30, 2026
Kind: B2

External Links

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Abstract

A vehicle brake system includes a service brake system having a service brake circuit and a trailer brake control system. The trailer brake control system includes a trailer brake valve with a service brake demand input port connected to the service brake circuit and a trailer service brake demand output port connected to a trailer brake control coupling. The output at the trailer brake demand output port is dependent on the pressure applied at the service brake demand input port. An electronic trailer brake control system has a control valve to fluidly connect a source of pressurized fluid with the trailer brake control coupling to trigger actuation of a service brake function on the trailer. The electronic trailer brake control system includes an ECU configured to actuate the control valve to apply service brakes on the trailer if it determines that the vehicle is at risk of jack-knifing.

Claims (41)

1 . A vehicle brake system comprising:

a source of pressurized fluid;

a service brake system having at least one service brake fluid circuit configured to forward a service brake demand of an operator;

a park brake system having at least one park brake fluid circuit configured to forward a park brake demand;

a trailer brake control system for connection to a trailer drawn by a vehicle carrying the vehicle brake system, the trailer brake control system having a trailer brake control coupling and a trailer brake valve, the trailer brake valve comprising:

a service brake demand input port;

a park brake demand input port;

a trailer brake demand output port for connection to the trailer brake control coupling, the trailer brake valve configured to provide a fluid pressure output at the trailer brake demand output port which is dependent on the fluid pressure applied at the service brake demand input port or the parking brake demand input port; and

an electronic trailer brake control system including a control valve operative to selectively connect the trailer brake control coupling with the source of pressurized fluid, the electronic trailer brake control system being operative in use to selectively supply pressurized fluid indicative of the service brake demand or the park brake demand for the trailer to the trailer brake control coupling;

wherein the vehicle brake system further comprises a shuttle valve configured to fluidly connect the trailer brake demand output port and an output fluid line of the electronic trailer brake control system to the trailer brake control coupling; and

wherein the electronic trailer brake control system comprises a piloted relay valve operative to selectively connect an input of the shuttle valve to the source of pressurized fluid, operation of the piloted relay valve being controlled by the control valve.

2 . The vehicle brake system of claim 1 , wherein the electronic trailer brake control system comprises an electronic control system including an electronic control unit (ECU), the ECU being configured in use to actuate the control valve to supply the pressurized fluid indicative of a brake demand for the trailer to the trailer brake control coupling in dependence on meeting at least one operational condition selected from the group consisting of operational conditions of the vehicle and operational conditions of a trailer towed by the vehicle.

3 . The vehicle brake system of claim 2 , wherein the ECU is configured in use to actuate the control valve to supply the pressurized fluid indicative of a brake demand for the trailer to the trailer brake control coupling in dependence on meeting at least one operational condition indicative of a PUSH condition.

4 . The vehicle brake system of claim 1 , wherein the control valve is an electronically actuatable solenoid valve operative to cause a second pressurized fluid indicative of a service brake demand for the trailer to be forwarded to the trailer brake control coupling when activated.

5 . The vehicle brake system of claim 1 , wherein the control valve has an inlet port fluidly connected with the source of pressurized fluid and an outlet port connected with a control port of the piloted relay valve, the control valve being movable between an inoperative position in which the inlet and outlet ports are disconnected and at least one operative position in which the inlet and outlet ports are fluidly connected and the control port of the piloted relay valve is connected with the source of pressurized fluid.

6 . The vehicle brake system of claim 1 , wherein the piloted relay valve is connected in a fluid line between the source of pressurized fluid and the inlet of the shuttle valve, the piloted valve being biased to an inoperative position in which the shuttle valve inlet is not connected with the source of pressurized fluid and movable to at least one operative position in which the inlet of the shuttle valve is connected with the source of pressurized fluid through the piloted valve in response to the application of fluid pressure at the control port to overcome the bias force.

7 . The vehicle brake system of claim 1 , wherein the piloted valve is a proportional valve configured such that, in use, the pressure of fluid directed to the trailer brake control coupling is dependent on the fluid pressure applied at a control port of the piloted valve.

8 . The vehicle brake system of claim 1 , further comprising a pressure discharge valve connected in a fluid line between the control valve and a control port of the piloted relay valve.

9 . The vehicle brake system of claim 1 , wherein the service brake system is a hydraulic brake system and the source of pressurized fluid is a source of pressurized air.

10 . The vehicle brake system of claim 1 , wherein the service brake system is a pneumatic brake system and the source of pressurized fluid is a source of pressurized air.

11 . An agricultural vehicle comprising the vehicle brake system of claim 1 .

12 . A vehicle brake system of claim 1 , comprising:

a source of pressurized fluid;

a service brake system having at least one service brake fluid circuit configured to forward a service brake demand of an operator:

a park brake system having at least one park brake fluid circuit configured to forward a park brake demand;

a service brake demand input port;

a park brake demand input port; p 2 a trailer brake demand output port for connection to the trailer brake control coupling, the trailer brake valve configured to provide a fluid pressure output at the trailer brake demand output port which is dependent on the fluid pressure applied at the service brake demand input port or the parking brake demand input port; and

wherein the electronic trailer brake control system is configured to supply fluid to the trailer brake control coupling at a pressure below a maximum pressure of the trailer service brake system.

13 . The vehicle brake system of claim 12 , further comprising a first pressure-limiting valve and a second pressure-limiting valve, wherein the first pressure-limiting valve is configured to limit a pressure applied by the source of pressurized fluid at a first threshold pressure, wherein the second pressure-limiting valve is in a fluid line between the source of pressurized fluid and the control valve, and wherein the second pressure-limiting valve is configured to limit the fluid pressure level through the control valve to a second threshold pressure lower than the first threshold pressure.

14 . A vehicle brake system comprising:

a source of pressurized fluid;

a service brake system having at least one service brake fluid circuit configured to forward a service brake demand of an operator;

a park brake system having at least one park brake fluid circuit configured to forward a park brake demand;

a service brake demand input port;

a park brake demand input port;

wherein the vehicle brake system further comprises a pressure sensor for monitoring a pressure of fluid directed to the trailer brake control coupling, the electronic trailer brake control system being operative in dependence on an output from the pressure sensor to maintain the pressure of the fluid directed to the trailer brake control coupling at a predetermined level lower than a pressure of the source of pressurized fluid.