A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal.

A brake retarder valve for a tractor-trailer combination includes a valve housing and a valve assembly. The valve assembly includes a poppet valve biased by a spring and a gravity spool. The valve assembly is selectively operable between the operative closed configuration and an open configuration in response to a resultant of the fluid pressure between a trailer axle brake and a tractor axle brake. The tractor axle brake is actuated with a time delay from actuation of the trailer axle brake. This delay is actuation of the tractor axle brake prevents jack knifing of the trailer onto the tractor in a tractor-trailer combination, thereby ensuring safety during operation of a tractor-trailer combination.

A controller for a parking brake system for a commercial vehicle is disclosed. The controller receives a signal indicative of a request to park a tractor, a signal indicative of a request to supply air to a trailer and a signal indicative of a vehicle operating condition. The controller transmits a control signal to a tractor parking brake device and a trailer air supply device in order to park the tractor and maintain the air supply to the trailer to suspend the parking of the trailer in response to the signals.

A valve system includes an isolation check valve delivering pneumatic fluid as a supply pressure, a double-check valve adapted to deliver a braking demand control signal of the pneumatic fluid based on a higher of a first braking demand in a first pneumatic braking circuit and a second braking demand in a second pneumatic braking circuit, and a control module. The control module is adapted to receive the supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid based on the braking demand control signal, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal.

A valve system includes a control module on a tractor portion of a vehicle adapted to receive a supply pressure as a control module supply pressure of the pneumatic fluid, receive a control module control pressure of the pneumatic fluid, and deliver a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure. A park control module selectively transmits the pneumatic fluid at the supply pressure based on a park brake control signal. A supply glad-hand fluidly communicates the selectively transmitted supply pressure of the pneumatic fluid to supply a brake on an associated trailer portion of the vehicle. A control glad-hand fluidly communicates the control module delivery pressure of the pneumatic fluid to control the brake on the associated trailer portion of the vehicle. An exhaust valve, which fluidly communicates with both the selectively transmitted supply pressure and the control module delivery pressure, exhausts the control module delivery pressure of the pneumatic fluid from the control glad-hand.

A brake retarder valve for a tractor-trailer combination includes a valve housing and a valve assembly. The valve assembly includes a poppet valve biased by a spring and a gravity spool. The valve assembly is selectively operable between the operative closed configuration and an open configuration in response to a resultant of the fluid pressure between a trailer axle brake and a tractor axle brake. The tractor axle brake is actuated with a time delay from actuation of the trailer axle brake. This delay is actuation of the tractor axle brake prevents jack knifing of the trailer onto the tractor in a tractor-trailer combination, thereby ensuring safety during operation of a tractor-trailer combination.

An electropneumatic trailer control module (100; 300; 500) with a housing structure (100a; 300a; 500a) includes a manual brake pressure port (154) receiving a driver's brake demand pressure component, a spring-supported electropneumatic input valve (104) with at least two ports and being capable of switching between two positions (open or closed), an electropneumatic brake pressure port (144; 146) for receiving an electropneumatic brake pressure component from at least one independent pressure source (138; 140), and a relay valve (112) including a control port (110), a supply port (114), an outlet port (116), and a relief port (118). The spring-supported electropneumatic input valve (104) is retained in an open position when there is no electronic activation of the spring-supported electropneumatic input valve (104). A tractor protection module (124; 324; 524) is provided within the housing structure (100a; 300a; 500a) of the electropneumatic trailer control module (100; 300; 500).

Various embodiments of a tractor controller for monitoring trailer brake applications is disclosed. The control logic of the tractor control is capable of receiving a signal indicative of a trailer brake application; receiving a signal indicative of a foot brake application; totaling a number of signals indicative of a trailer brake application for a predetermined time period; and totaling a number of signals indicative of a foot brake application for the predetermined time period. The control logic then compares the total number of signals indicative of a trailer brake application with the total number of signals indicative of a foot brake application. The control logic records a flag in response to the total number of signals indicative of a trailer brake application being greater than the total number of signals indicative of a foot brake application.

A controller for a parking brake system for a commercial vehicle is disclosed. The controller receives a signal indicative of a request to park a tractor, a signal indicative of a request to supply air to a trailer and a signal indicative of a vehicle operating condition. The controller transmits a control signal to a tractor parking brake device and a trailer air supply device in order to park the tractor and maintain the air supply to the trailer to suspend the parking of the trailer in response to the signals.

Various embodiments of a tractor controller for monitoring trailer brake applications is disclosed. The control logic of the tractor control is capable of receiving a signal indicative of a trailer brake application; receiving a signal indicative of a foot brake application; totaling a number of signals indicative of a trailer brake application for a predetermined time period; and totaling a number of signals indicative of a foot brake application for the predetermined time period. The control logic then compares the total number of signals indicative of a trailer brake application with the total number of signals indicative of a foot brake application. The control logic records a flag in response to the total number of signals indicative of a trailer brake application being greater than the total number of signals indicative of a foot brake application.