A brake system includes a brake actuator configured to engage a brake to limit movement of a tractive element, an air-to-hydraulic intensifier coupled to the brake actuator where the air-to-hydraulic intensifier is configured to receive a supply of air and provide a hydraulic fluid to the brake actuator based on the supply of air to overcome a brake biasing force of the brake actuator to disengage the brake actuator from the brake to permit movement of the tractive element, a hydraulic reservoir coupled to the air-to-hydraulic intensifier, and a valve. The valve includes a first port fluidly coupled to the air-to-hydraulic intensifier, a second port fluidly coupled to the hydraulic reservoir, a third port fluidly coupled to the brake actuator, and a valve gate that is repositionable between a first position that couples the first port to the third port and a second position that couples the second port to the third port.

A vehicle braking system includes an assistance device having a vacuum pump driven by an engine for communicating vacuum to a chamber of the assistance device. A control valve is interposed along a fluid line between the pump and the chamber. The control valve is in its first operative condition, where the inlet side of the vacuum pump communicates with the chamber, when pressure within the chamber is above a predetermined value; and is in its second operative condition, where the inlet side of the vacuum pump communicates with the atmosphere, when pressure within the chamber is below a predetermined value. In this second condition the pump intakes air from and feeds air into the atmosphere, thereby reducing the energy consumption by the engine required for driving the pump during stages where, within the chamber, there is a vacuum sufficient for the regular operation of the braking system.

The various embodiments of the present disclosure are directed to devices, system and processes for detecting saturation of a received signal in a PAS system. A process may include detecting, in a received signal and during a measurement interval, one or more correlated signal levels. Based on one or more results of the detecting, the process may include identifying in a correlated output signal portions of the received signal which exceed a given magnitude threshold during the measurement interval and providing the correlated output signal to an electronic control unit (ECU). A magnitude detector outputs the correlated output signal. A saturation detector determines whether the received signal is saturated during a portion of a measurement interval. When the received signal is saturated, a saturation signal is generated and provided on a delayed basis to the ECU such that it is provided substantially contemporaneously with the correlated output signal.

The various embodiments of the present disclosure are directed to devices, system and processes for detecting saturation of a received signal in a PAS system. A process may include detecting, in a received signal and during a measurement interval, one or more correlated signal levels. Based on one or more results of the detecting, the process may include identifying in a correlated output signal portions of the received signal which exceed a given magnitude threshold during the measurement interval and providing the correlated output signal to an electronic control unit (ECU). A magnitude detector outputs the correlated output signal. A saturation detector determines whether the received signal is saturated during a portion of a measurement interval. When the received signal is saturated, a saturation signal is generated and provided on a delayed basis to the ECU such that it is provided substantially contemporaneously with the correlated output signal.

A brake control system includes one or more processors communicatively connected to at least one sensor configured to output at least one property measurement of air in a brake pipe of a vehicle braking assembly. The one or more processors are configured to determine, based on the at least one property measurement, a pressure reduction lower limit (PRLL) in the brake pipe. The one or more processors are further configured to control movement of a vehicle system that includes the brake pipe to enforce the PRLL by preventing a pressure reduction in the brake pipe that is less than the PRLL while one or more air reservoirs of the vehicle braking assembly are at a reduced charge state.

A method includes steps for controlling a pneumatic braking system of a trailer vehicle which is connected to a tow vehicle equipped with a hydraulic or pneumatic braking system. At the start of an actuation of the foot brake valve, an electrical switch is closed or opened, and a switching signal is transmitted to an electronic control unit as a braking start signal for an incipient braking process. A brake value sensor detects a brake value representative of the drivers current deceleration request and transmits the brake value to the electronic control unit as a brake value signal. The brake value sensor is used for determining the incipient braking process, and a backup valve is only deactivated by switching a redundancy valve from an open position to a blocking position if the brake value signal detected by the brake value sensor has reached or exceeded a predefined minimum signal value.

A method includes steps for controlling a pneumatic braking system of a trailer vehicle which is connected to a tow vehicle equipped with a hydraulic or pneumatic braking system. At the start of an actuation of the foot brake valve, an electrical switch is closed or opened, and a switching signal is transmitted to an electronic control unit as a braking start signal for an incipient braking process. A brake value sensor detects a brake value representative of the drivers current deceleration request and transmits the brake value to the electronic control unit as a brake value signal. The brake value sensor is used for determining the incipient braking process, and a backup valve is only deactivated by switching a redundancy valve from an open position to a blocking position if the brake value signal detected by the brake value sensor has reached or exceeded a predefined minimum signal value.

A liftgate alert apparatus for alerting drivers when a liftgate is down before driving includes a pressure switch configured to be coupled to an air line of an airbrake system of a truck or a trailer. The pressure switch is closed when the airbrake system is activated. A roller switch is in operational communication with the pressure switch and is configured to be coupled to a liftgate. The roller switch is closed when the liftgate is in a down position. An alarm is in operational communication with the pressure switch, the roller switch, and a power source. The alarm has an alarm ground wire. The alarm is configured to be coupled within a cab of the truck or on a front end of the trailer and activates an audio and or visual alert when both the pressure switch and the roller switch are closed.

A brake system includes a brake actuator configured to engage a brake to limit movement of a tractive element, an air-to-hydraulic intensifier coupled to the brake actuator where the air-to-hydraulic intensifier is configured to receive a supply of air and provide a hydraulic fluid to the brake actuator based on the supply of air to overcome a brake biasing force of the brake actuator to disengage the brake actuator from the brake to permit movement of the tractive element, a hydraulic reservoir coupled to the air-to-hydraulic intensifier, and a valve. The valve includes a first port fluidly coupled to the air-to-hydraulic intensifier, a second port fluidly coupled to the hydraulic reservoir, a third port fluidly coupled to the brake actuator, and a valve gate that is repositionable between a first position that couples the first port to the third port and a second position that couples the second port to the third port.

A liftgate alert apparatus for alerting drivers when a liftgate is down before driving includes a pressure switch configured to be coupled to an air line of an airbrake system of a truck or a trailer. The pressure switch is closed when the airbrake system is activated. A roller switch is in operational communication with the pressure switch and is configured to be coupled to a liftgate. The roller switch is closed when the liftgate is in a down position. An alarm is in operational communication with the pressure switch, the roller switch, and a power source. The alarm has an alarm ground wire. The alarm is configured to be coupled within a cab of the truck or on a front end of the trailer and activates an audio and or visual alert when both the pressure switch and the roller switch are closed.