Patent Publication Number: US-11021142-B2

Title: Trailer control valve with integrated trailer supply

Description:
BACKGROUND OF THE INVENTION 
     a. Field of the Invention 
     This invention relates to a trailer control valve for a tractor-trailer. In particular, the invention relates to a trailer control valve that controls delivery of fluid to trailer brakes while providing protection for the tractor air supply. 
     b. Background Art 
     Conventional tractors include components for generating and storing pressurized fluid and for routing and delivering that fluid to wheel brakes on the tractor and any trailers coupled to the tractor in order to release parking brakes and apply service brakes. These components include various valves that control routing and delivery of fluid from a fluid source to the brakes. To control routing and delivery of fluid to the trailers, the tractor typically includes a relay valve as well as a tractor protection valve. The relay valve increases the volume of fluid, and therefore the speed, at which fluid is delivered to, and exhausted from, the wheel brakes on the trailer in order to eliminate lag times between the commanded and actual application and release of the trailer brakes. The tractor protection valve transmits pneumatic signals relating to operation of the trailer wheel brakes from the tractor to the trailer while also protecting the fluid supply for the tractor in the event of a break in the fluid connection between the tractor and trailer. Although conventional relay and tractor protection valves function well for their intended purpose, the use of separate relay and tractor protection valves increases the part count, cost and complexity of the fluid circuit on the tractor including the number of pneumatic connections. 
     The inventors herein have recognized a need for a trailer control valve for a tractor that will minimize and/or eliminate one or more of the above-identified deficiencies. 
     BRIEF SUMMARY OF THE INVENTION 
     This invention relates to a trailer control valve for a tractor-trailer. In particular, the invention relates to a trailer control valve that controls delivery of fluid to trailer brakes while providing protection for the tractor air supply. 
     A trailer control valve for a tractor in accordance with one embodiment includes a body defining a supply port and first and second delivery ports. The supply port is configured for fluid communication with a fluid source on the tractor. The first delivery port is in fluid communication with the supply port and configured for fluid communication with a first glad-hand connector through which fluid is supplied from the tractor to a trailer coupled to the tractor for releasing a parking brake on the trailer. The second delivery port is configured for fluid communication with a second glad-hand connector through which fluid is supplied from the tractor to the trailer for applying a service brake on the trailer. The valve further includes a relay valve supported within the body. The relay valve including a valve member configured to move between a first position preventing fluid communication between the supply port and the second delivery port and a second position permitting fluid communication between the supply port and the second delivery port. 
     A trailer control valve for a tractor in accordance with another embodiment includes a body defining a supply port and first and second delivery ports. The supply port is configured for fluid communication with a fluid source on the tractor. The first delivery port is in fluid communication with the supply port and configured for fluid communication with a first glad-hand connector through which fluid is supplied from the tractor to a trailer coupled to the tractor for releasing a parking brake on the trailer. The second delivery port is configured for fluid communication with a second glad-hand connector through which fluid is supplied from the tractor to the trailer for applying a service brake on the trailer. The valve further includes a relay valve supported within the body. The relay valve including a valve member configured to move between a first position preventing fluid communication between the supply port and the second delivery port and a second position permitting fluid communication between the supply port and the second delivery port. A first pressure sensor is supported within the body and configured to generate a first pressure signal indicative of fluid pressure at the first delivery port. A second pressure sensor is supported within the body and configured to generate a second pressure signal indicative of fluid pressure at the second delivery port. 
     A trailer control valve for a tractor in accordance with the present teachings represent an improvement as compared to valves used in conventional tractor fluid control circuits. In particular, the valve integrates functionality of a relay valve and a tractor protection valve to reduce part count, cost and complexity of the tractor fluid circuit including the number of pneumatic connections. In some embodiments, the trailer control valve also monitors the trailer supply and control fluid pressures to facilitate detection of the presence of trailers coupled to the tractor. 
     The foregoing and other aspects, features, details, utilities, and advantages of the present invention will be apparent from reading the following description and claims, and from reviewing the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic representation of system for controlling wheel brakes on a tractor and trailer in accordance with one embodiment of the present teachings. 
         FIGS. 2A-2B  are perspective and side views of a trailer control valve of the system of  FIG. 1 . 
         FIG. 3  is a diagrammatic representation of the trailer control valve of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views,  FIG. 1  illustrates a vehicle  10  containing a tractor or power unit  12  and one or more trailers or towed units  14 . Tractor  12  contains a power unit, such as an internal combustion engine, and steering and drive axles each of which support one or more wheels at either end. Trailers  14  are provided to store freight and are detachably coupled to tractor  12 . Each trailer  14  is supported on one or more trailer axles, each of which may support one or more wheels at either end. Although vehicle  10  includes a single trailer  14  in the illustrated embodiment, it should be understood that the number of trailers  14  attached to tractor  12  of vehicle  10  may vary. 
     Vehicle  10  further includes a braking system  16  configured to brakes wheels on tractor  12  and trailer  14  in order to slow or stop movement of vehicle  10 . System  16  may include components on both tractor  12  and trailer  14  that may be in fluid and/or electrical communication using conventional connectors between tractor  12  and trailer  14 . Braking system  16  may include wheel brakes  18 , a fluid circuit  20  that supplies fluid pressure to wheel brakes  16 , various sensors (not shown, but including transmission speed sensors, wheel speed sensors, pressure sensors, a steer angle sensor, a yaw rate sensor, and load sensors) and a controller  22 . 
     Wheel brakes  18  are configured to apply a braking force to the vehicle wheels. In the illustrated embodiment, brakes  18  comprise disc brakes in which a carrier supports brake pads on opposite sides of a rotor rotating with the wheel and a brake actuator causes, responsive to fluid pressure delivered by fluid circuit  20 , movement of a caliper relative to the carrier to move the brake pads into and out of engagement with the rotor. It should be understood, however, that one or more of wheel brakes  18  may alternatively comprise drum brakes in which the brake actuator causes, responsive to fluid pressure delivered by fluid circuit  20 , movement of a cam or piston to move one or more brake shoes into engagement with a braking surface in a brake drum rotating with the vehicle wheel. Each wheel brake  18  defines a service brake. At least some of wheels brake  18  further define a parking or emergency brake. In one conventional wheel brake  18 , the brake actuator includes a spring that forces a pushrod in a first direction to move the caliper (disc brake) or cam/piston (drum brake) to apply the parking/emergency brake. Fluid pressure may be supplied to the actuator to overcome the force of the spring and cause movement of the pushrod in a second direction to release the parking/emergency brake. Fluid pressure may then applied to another portion of the actuator to again urge the pushrod in the first direction to apply the service brake. 
     Fluid circuit  20  generates fluid pressure within system  16  and controls the delivery of fluid pressure to the actuator of each wheel brake  18 . Circuit  20  may include means for generating and storing pressurized fluid including a fluid source  24  and means for routing and delivering fluid pressure to wheel brakes  18  including fluid conduits  26 , glad-hand connectors  28  between tractor  12  and trailer  14 , and various valves including foot pedal valve  30 , hand control valve  32 , and a trailer control valve  34  in accordance with the present teachings. Although only valves  30 ,  32  and  34  are illustrated in  FIG. 1 , it should be understood that circuit  20  may further include other conventional valves including relay valves to increase the volume of fluid, and therefore the speed, at which fluid is delivered to, and exhausted from, wheel brakes  18  in order to eliminate lag times between the commanded and actual application and release of brakes  18 , modulator valves that modulate fluid pressure delivered to wheel brakes  18  to implement anti-lock braking during a loss of traction, quick release valves to increase the speed at which fluid pressure is exhausted from wheel brakes  18  when brakes  18  are released, and a dash control valve that allows the vehicle operator to implement various functions including releasing parking brakes on tractor  12  or trailer  14  by supplying fluid pressure to oppose spring forces in the actuators for wheel brakes  18 . 
     Fluid source  24  is provided to generate and store pressurized fluid. Fluid source  24  may include one or more fluid reservoirs for storing compressed fluid used in applying wheel brakes  18 . Fluid source  24  may further include a compressor to draw in air and compress the air for delivery to the fluid reservoir or reservoirs. Fluid source  24  may further include one or more air dryers to collect and remove solid, liquid and vapor contaminants from pressurized fluid. 
     Fluid conduits  26  are used to transport fluid between fluid source  24 , glad-hand connectors  28 , valves  30 ,  32 ,  34  (and other valves not illustrated herein) and wheel brakes  18 . Conduits  26  may be made from conventional metals and/or plastics and have connectors at either end configured to join the conduits  26  to corresponding components of circuit  20 . 
     Glad-hand connectors  28  are used to transmit pressurized fluid from tractor  12  to trailer  14 . One of connectors  28  is used to transmit fluid used to release the parking brake of each wheel brake  18  on trailer  14 . The other connector  28  is used to transmit fluid used to apply the service brake of each wheel brake  18 . 
     Foot pedal valve  30  is provided to allow controlled application of the brakes  18  by the vehicle operator by selectively releasing fluid pressure from fluid source  24 . Valve  30  is supported within the cabin of tractor  12 . Actuation of valve  30  by the vehicle operator allows fluid pressure to flow from fluid source  24  to various valves in fluid circuit  20  including trailer control valve  34 . Valve  30  has fluid ports in fluid communication with fluid source  24  and trailer control valve  34 . 
     Hand control valve  32  allows the vehicle operator to control the service brakes of the wheel brakes  18  on trailer  14  independently of the service brakes of the wheel brakes  18  on tractor  12 . Valve  32  is supported within the cabin of tractor  12  and configured for actuation by hand. Actuation of valve  32  by the vehicle operator allows fluid pressure to flow from fluid source  24  to various valves in fluid circuit  20  involved in control of the wheel brakes  18  on trailer  14  including trailer control valve  34 . Valve  32  therefore has fluid ports in fluid communication with fluid source  24  and trailer control valve  34 . 
     Trailer control valve  34  transmits pneumatic signals relating to operation of the trailer wheel brakes  18  from the tractor  12  to the trailer  14 . In accordance with one aspect of the present teachings, valve  34  also protects the fluid supply for tractor  12  in the event of a brake in the fluid connection between tractor  12  and trailer  14 . In accordance with another aspect of the present teachings, valve  34  may also monitor the trailer supply and control fluid pressures to facilitate detection of the presence of trailers  14  coupled to the tractor  12 . Referring to  FIGS. 2A-B  and  3 , valve  34  includes a body  36  and a relay valve  38  and may further include double check valve  40 , electronically controlled valves  42 ,  44 ,  46 , and pressure sensors  48 ,  50 . 
     Body  36  provides structural support for, and positions and orients, the other components of valve  34  including relay valve  38 , double check valve  40 , electronically controlled valves  42 ,  44 ,  46 , and pressure sensors  48 ,  50 . Body  36  protects these components against external objects and elements. Body  36  is also configured for mounting on tractor  12 . Body  36  may be made from conventional metals or plastics. Body  36  defines a supply port  52 , delivery ports  54 ,  56 , and control ports  58 ,  60 . Referring to  FIG. 1 , supply port  52  is configured for fluid communication with a fluid source on tractor  12  such as fluid source  24 . Delivery port  54  is configured for fluid communication with a glad-hand connector  28  through which fluid is supplied from tractor  12  to trailer  14  to release the parking brakes in the wheel brakes  18  on trailer  14 . Referring to  FIG. 3 , delivery port  54  is in fluid communication with supply port  52  such that fluid pressure at supply port  52  is routed directly to delivery port  54 . Referring again to  FIG. 1 , delivery port  56  is configured for fluid communication with the other glad-hand connector  28  through which fluid may be supplied from tractor  12  to trailer  14  for application of the service brakes in the wheel brakes  18  on trailer  14 . Control ports  58 ,  60  are configured for fluid communication with control valves in tractor  12 . In particular, control port  58  may be configured for fluid communication with foot pedal valve  30  while control port  60  may be configured for fluid communication with hand control valve  32 . Referring to  FIGS. 2A-2B , body  36  further defines a terminal connector  62 . Connector  62  defines a plurality of electrical terminals or pins for transmitting and/or receiving electrical signals. Valve  34  may communicate with controller  22  and other components and systems on vehicle  10  through connector  62  using a conventional vehicle communication bus such as a controller area network (CAN) (or another communication medium such as power line communication (PLC)). Referring to  FIG. 3 , in the illustrated embodiment, connector  62  defines eight terminals or pins with pin  64  providing power to valves  42 ,  44 ,  46  and pressure sensors  48 ,  50 , pin  66  acting as a ground, pins  68 ,  70 ,  72  receiving control signals for valves  42 ,  44 ,  46 , pins,  74 ,  76 , transmitting pressure signals from pressure sensors  48 ,  50 , and pin  78  providing a reference pressure sensor supply voltage for controller diagnostic purposes. 
     Referring to  FIG. 3 , relay valve  38  controls the delivery of fluid pressure from supply port  52  on body  36  to delivery port  56 . Valve  38  includes a valve member  80  configured to move between a first position preventing fluid communication between supply port  52  and delivery port  56  and a second position permitting fluid communication between supply port  52  and delivery port  56 . Valve  38  includes an inlet port  82 , an outlet port  84  and a control port  86 . Inlet port  82  is in fluid communication with supply port  52  of body  36 . Outlet port  84  is in fluid communication with delivery port  56  of body  36 . Control port  86  is configured for fluid communication with supply port  52  or one of control ports  58 ,  60  on body  36  depending on the positions of double check valve  40  and electronically controlled valves  42 ,  44 ,  46  as described in greater detail below. Control port  86  is therefore configured to receive pneumatic control signals from ports  52 ,  58 ,  60  that control movement of the valve member  80 . 
     Double check valve  40  provides fluid from the highest pressure input among control ports  58 ,  60  to control port  86  of relay valve  38 . In the absence of actuation of foot pedal valve  30  or hand control valve  32 , fluid will not flow from either control port  58 ,  60  to control port  86  on relay valve  38  and (unless fluid flow is permitted from supply port  52  to control port  86  as discussed below), relay valve  38  will prevent fluid communication between supply port  52  and delivery port  56  on body  36 . Actuation of one of pedal valve  30  or hand control valve  32  will create a pressure differential that opens check valve  40  and permits fluid flow from the corresponding control port  58 ,  60  to control port  86  on relay valve  38  (provided electronic control valve  42  is open as discussed below), causing valve member  80  to move to a position permitting fluid flow between inlet port  82  and outlet port  84  on relay valve  38  and, therefore, between supply port  52  and delivery port  56  on body  36  of valve  34 . Double check valve  40  has inlet ports in fluid communication with control ports  58 ,  60  on body  36  and an outlet port in fluid communication with control port  86  of relay valve  38 . 
     Electronically controlled valves  42 ,  44 ,  46  provide an alternative means to foot pedal valve  30  and hand control valve  32  for controlling relay valve  38 . In the illustrated embodiment, valves  42 ,  44 ,  46  comprise solenoid valves. It should be understood, however, that valves  42 ,  44 ,  46  may assume other forms including motorized valves or piezo valves. Valve  42  is configured to control delivery of fluid pressure from control ports  58 ,  60  on body  36  to control port  86  on relay valve  38 . Valves  44 ,  46  are configured to control delivery of fluid pressure from supply port  52  on body  36  to control port  86  on relay valve  38  (through restrictor  88 ). Valve  42  is normally open and valves  44 ,  46  are normally closed to permit fluid flow from control ports  58 ,  60  on body  36  to control port  86  on relay valve  38  upon actuation of foot pedal valve  30  or hand control valve  32 . In certain circumstances, however, it may be desirable to actuate the service brakes on trailer  14  in the absence of actuation of foot pedal valve  30  or hand control valve  32  including in operator controlled electronic braking systems, advanced driver assistance systems (ADAS) such as collision avoidance systems, adaptive cruise control systems and platooning systems. In these circumstances, signals may be generated by controller  22  or another system or component on vehicle  10  and delivered to valves  42 ,  44 ,  46  through pins  68 ,  70 ,  72  of connector  62  to close valve  42  and open valves  44 ,  46  and modulate and deliver fluid pressure from supply port  52  of body  36  to control port  86  of relay valve  38 . 
     Pressure sensors  48 ,  50  provide an indication of the fluid pressure at delivery ports  56 ,  54 , respectively. Sensors  48 ,  50  are supported within body  36  of valve  34 . Sensor  48  generates a pressure signal indicative of the fluid pressure at delivery port  56  while sensor  50  generates a pressure signal indicative of the fluid pressure at delivery port  54 . In this manner, valve  34  allows monitoring of the fluid pressure in both fluid lines to trailer  14  (unlike conventional systems that measure pressure on only the control line) close to the physical connection with trailer  14 . The measurement on both lines enables system  16  to provide accurate detection of the presence of trailer  14 . Pressure sensors  48 ,  50  output pressure signals on pins  74 ,  76  of connector  62 . Each pressure sensor  48 ,  50  is also in electrical communication with pin  78  providing a reference pressure value and a pin  66  tied to electrical ground. 
     Referring again to  FIG. 1 , controller  22  may be used to control the operation of various systems and components of vehicle  10 . Controller  22  may, for example, be used to control braking and stability control systems in vehicle  10  by controlling the operation of various fluid control valves including relay valves and modulator valves. In accordance with one aspect of the present teachings, controller  22  may be provided to control the operation of trailer control valve  34 . In accordance with another aspect, controller  22  may also detect the presence of a trailer  14  coupled to tractor  12  responsive to signals generated by valve  34  and, in particular, by pressure sensors  48 ,  50 . Controller  22  may comprise a programmable microprocessor or microcontroller or may comprise an application specific integrated circuit (ASIC). Controller  22  may include a memory and a central processing unit (CPU). Controller  22  may also include an input/output (I/O) interface including a plurality of input/output pins or terminals through which the controller may receive a plurality of input signals and transmit a plurality of output signals. The input signals may include signals received from a variety of sources providing information about the operation of vehicle  10  including, for example, various sensors such as wheel speed sensors, lateral acceleration sensors, steer angle sensors, brake pressure sensors, vehicle load sensors, yaw rate sensors, tire pressure management sensors, and collision avoidance sensors (which may comprise, for example, RADAR devices, LIDAR devices or cameras). The input signals may also include inputs from user interfaces through which the vehicle operator can input data regarding the vehicle  10  and/or direct the operation of vehicle  10 . In accordance with present teachings, the input signals may further include signals generated by pressure sensors  48 ,  50  in valve  34 . The output signals may include signals transmitted to various vehicle control systems such as anti-lock braking and stability control systems and user interfaces on vehicle  10 . In accordance with the present teachings, the output signals may further include signals generated to control electronically controlled valves  42 ,  44 ,  46  within valve  34 . Controller  22  may communicate with other devices and systems within vehicle  10  over a conventional vehicle communication bus such as a controller area network (CAN) (or another communication medium such as power line communication (PLC)). 
     A trailer control valve  34  for a tractor  12  in accordance with the present teachings represent an improvement as compared to valves used in conventional tractor fluid control circuits. In particular, the valve  34  integrates functionality of a relay valve and a tractor protection valve to reduce part count, cost and complexity of the tractor fluid circuit  20  including the number of pneumatic connections. In some embodiments, the trailer control valve  34  also monitors the trailer supply and control fluid pressures to facilitate detection of the presence of trailers  14  coupled to the tractor  12 . 
     While the invention has been shown and described with reference to one or more particular embodiments thereof, it will be understood by those of skill in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.