Valve system and method for controlling same

A valve system, including:

• a first check valve including a first check valve pneumatic supply port and a first check valve pneumatic delivery port;
• a second check valve including a second check valve pneumatic supply port and a second check valve pneumatic delivery port, the first check valve pneumatic delivery port fluidly communicating with the second check valve pneumatic delivery port and a higher of respective pneumatic supply pressures of a pneumatic fluid at the first and second check valve pneumatic supply ports being fluidly transmitted to the first and second check valve pneumatic delivery ports as a pneumatic supply pressure of the pneumatic fluid;
• a double-check valve delivering a braking demand pneumatic fluid control signal 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;
• a control module, including:
• a pneumatic supply port fluidly communicating with both the first and second check valve pneumatic delivery ports and fluidly receiving the pneumatic supply pressure of the pneumatic fluid;
• a pneumatic control port receiving the braking demand pneumatic fluid control signal;
• and
• a pneumatic delivery port delivering a pneumatic fluid at a delivery pressure based on the braking demand pneumatic fluid control signal;
• a park control module selectively transmitting the pneumatic fluid at the supply pressure based on a park brake control signal;
• and
• a tractor protection valve including a tractor protection valve input port, fluidly communicating with the control module pneumatic delivery port, and a tractor protection valve output port, the pneumatic fluid at the delivery pressure from the control module pneumatic delivery port being delivered from the tractor protection valve input port to the tractor protection output port based on a state of the tractor protection valve.

A method for controlling a pressure of a pneumatic fluid delivered from a tractor protection module, the method comprising:

• delivering the pneumatic fluid from an isolation check valve at a supply pressure;
• delivering 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, from a double-check valve;
• receiving the supply pressure as a control module supply pressure of the pneumatic fluid;
• receiving a control module control pressure of the pneumatic fluid based on the braking demand control signal;
• receiving the supply pressure as a park control module supply pressure of the pneumatic fluid;
• receiving a park control module control signal based on a desired park state of an associated tractor;
• delivering the park control module supply pressure as a park control module delivery pressure to the tractor protection module based on the park control module control signal;
• delivering a control module delivery pressure of the pneumatic fluid based on the control module supply pressure and the control module control pressure;
• and
• delivering the pneumatic fluid from the tractor protection module at the control module delivery pressure based on the park control module delivery pressure, the pneumatic fluid being delivered from the tractor protection module at the control module delivery pressure if the park control module delivery pressure is above a predetermined tractor protection supply pressure.

A valve system, including:

• an isolation check valve delivering pneumatic fluid as a supply pressure;
• a tractor protection module delivering the pneumatic fluid at a tractor protection delivery pressure based on the supply pressure and a trailer park brake pressure of the pneumatic fluid;
• a relay valve adapted to:
• receive the supply pressure;
• receive a relay valve control pressure of the pneumatic fluid based on one of i) a braking demand control signal and ii) the supply pressure;
• and
• deliver a relay control pressure of the pneumatic fluid, based on the supply pressure and the relay valve control pressure to an input port of the tractor protection module;
• a first control valve set to fluidly communicate the braking demand control signal as the relay valve control pressure based on a current braking mode, the current braking mode being one of an operator controlled braking mode, a system increasing pressure mode, and a system holding pressure mode;
• a second control valve set to fluidly communicate the supply pressure as the relay valve control pressure based on the current braking mode, wherein:
• if the current braking mode is the operator initiated braking mode, the first control valve is set to fluidly communicate the braking demand control signal as the relay valve control pressure, while the second control valve set to not fluidly communicate the control module supply pressure as the relay valve control pressure;
• if the current braking mode is the system increasing pressure mode, the first control valve is set to not fluidly communicate the braking demand control signal as the relay valve control pressure, while the second control valve is set to fluidly communicate the control module supply pressure as the relay valve control pressure;
• and
• if the current braking mode is the system holding pressure mode, neither the first control valve is set to fluidly communicate the braking demand control signal as the relay valve control pressure nor the second control valve is set to fluidly communicate the control module supply pressure as the relay valve control pressure;
• and
• means for controlling the tractor protection delivery pressure.