Automatic work brake

Abstract

A vehicle, air brake system is presented with an improved service work brake arrangement. The arrangement may provide a service work brake function or both a service work brake function and a parking brake function for the vehicle. The arrangement may provide an improved service work brake arrangement disposed within a housing for reducing the number of components and plumbing required to achieve this functionality versus prior known systems. The arrangement may utilizes a pneumatic latching valve to deliver pressurized air for applying a vehicle's service brakes. The pneumatic latching valve opens upon receiving a pneumatic control signal from an electronically controlled valve and closes upon receiving a pneumatic control signal from another source. In addition, a controller and control logic may be provided for controlling the arrangement.

1 . A controller for an automatic work brake on a vehicle, the controller comprising:
 at least one input receiving at least one input signal indicative of a status of the vehicle representing a speed of the vehicle and a service brake pedal position;   a processor determining, based on the input signal, whether to automatically apply the automatic work brake; and   an output delivering a control signal for automatically engaging the work brake based on the determination of the processor.   
     
     
         2 . The controller for an automatic work brake on a vehicle as set forth in  claim 1 , wherein:
 the at least one input signal indicative of a status of the vehicle represents at least one of a driver present, a fault status of a vehicle system, a rotational speed of an engine of the vehicle, a throttle demand of the engine of the vehicle, a transmission gear engaged, a voltage of the vehicle, and a supply pressure of a vehicle brake system.   
     
     
         3 . The controller for an automatic work brake on a vehicle as set forth in  claim 1 , wherein:
 the processor determines if the vehicle is in one of a SAFE status and an UNSAFE status based on the at least one input signal.   
     
     
         4 . The controller for an automatic work brake on a vehicle as set forth in  claim 3 , wherein:
 the processor determines the vehicle is in the SAFE status if the speed of the vehicle is less than a predetermined speed and the service brake pedal is depressed.   
     
     
         5 . The controller for an automatic work brake on a vehicle as set forth in  claim 4 , wherein:
 if the processor determines the vehicle is in the SAFE status, the processor determining to automatically apply the work brake.   
     
     
         6 . The controller for an automatic work brake on a vehicle as set forth in  claim 4 , wherein:
 if the processor determines the vehicle is in the SAFE status, the processor determining to automatically release the work brake if a throttle demand of the engine is above a predetermined level.   
     
     
         7 . The controller for an automatic work brake on a vehicle as set forth in  claim 3 , wherein:
 if the work brake is applied, the processor determines the vehicle is in the UNSAFE status if a fault status of the vehicle system is faulted; and   if the processor determines the vehicle is in the UNSAFE status, the processor enforcing a failsafe function.   
     
     
         8 . The controller for an automatic work brake on a vehicle as set forth in  claim 1 , wherein:
 if the processor determines to automatically apply the work brake, the output delivers a control signal for activating a valve to engage the work brake.   
     
     
         9 . A system for automatically applying a work brake, the system comprising:
 a first valve controlling pressure delivered to a service brake;   a controller, including:
 at least one input signal indicative of a status of the vehicle representing a speed of the vehicle and a service brake pedal position; 
 a processor determining, based on the input signal, whether to automatically apply the automatic work brake; and 
 an output delivering a control signal to the first valve, for automatically engaging the service brake as the work brake, based on the determination of the processor. 
   
     
     
         10 . The system for automatically applying as work brake as set forth in  claim 9 , the system further including:
 a second valve including an outlet fluidly communicating with the service brake.   
     
     
         11 . The system for automatically applying a work brake as set forth in  claim 10 , wherein:
 the controller delivers an electronic control signal to the first valve; and   the first valve delivers a pneumatic open control signal to the second valve.   
     
     
         12 . The system for automatically applying a work brake as set forth in  claim 11 , wherein:
 the second valve is set to an open state for delivering fluid pressure to the service brake upon receiving the pneumatic open control signal from the first valve.   
     
     
         13 . The system for automatically applying a work brake as set forth in  claim 12 , wherein:
 the second valve latches in the open state and remains in the open state even after the pneumatic open control signal from the first valve ceases; and   the service brake acts as the work brake While the second valve is latched in the open state.   
     
     
         14 . The system for automatically applying a work brake as set forth in  claim 12 , wherein:
 the second valve is set to a closed state for not delivering fluid pressure to the service brake upon receiving a pneumatic close control signal from as fourth valve;   the second valve latches in the closed state and remains in the closed state even after the pneumatic close control signal ceases.   
     
     
         15 . The system for automatically applying a work brake as set forth in  claim 14 , wherein:
 the outlet of the fourth valve fluidly communicates with a closing control port of the second valve.   
     
     
         16 . The system for automatically applying a work brake as set forth in  claim 14 , wherein:
 the control signal delivered by the controller to the first valve is a first electronic control signal;   the controller also delivers a second electronic control signal the fourth valve based on the determination of the processor; and   the respective electronic control signals delivered to the first valve and the fourth valve, based on the determination of the processor, control the first valve and the fourth valve for automatically engaging and releasing the service brake as the work brake.   
     
     
         17 . The system for automatically applying a work brake as set forth in  claim 6 , wherein:
 the processor determines to automatically engage the service brake as the work brake if the service brake pedal is in a depressed position and the speed of the vehicle is less than a predetermined speed.   
     
     
         18 . The system for automatically applying a work brake as set forth in  claim 17 , wherein:
 the processor determines to automatically release the work brake if a throttle demand of the engine is above a predetermined level.   
     
     
         19 . The system for automatically applying a work brake as set forth in  claim 16 , wherein:
 if the processor determines to automatically apply the service brake as the work brake, the controller delivers the first electronic control signal to the first valve for setting the first valve to an open state;   while in the open state, the first valve delivers a pneumatic control signal to the opening control port of the second valve for setting the second valve to an open state; and   while in the open state, the outlet of the second valve fluidly communicates with the inlet of the second valve so that pressure from the inlet of the second valve is fluidly communicated to the service brake for actuating the service brake.   
     
     
         20 . The system for automatically applying, a work brake as set forth in  claim 19 , wherein:
 if the processor determines to automatically release the service brake as the work brake, the controller ensures the first electronic control signal is no longer delivered to the first valve while delivering the third electronic control signal to the fourth valve for setting the fourth valve to an open state;   while in the open state, the fourth valve delivers a pneumatic control signal to the closing control port of the second valve for setting the second valve to a closed state; and   while in the closed state, the outlet of the second valve does not fluidly communicate with the inlet of the second valve so that pressure from the inlet of the second valve is not fluidly communicated to the service brake so the service brake is not actuated.   
     
     
         21 . A controller for an automatic work brake on a vehicle, the controller comprising:
 at least one input receiving at least one input signal indicative of a status of the vehicle representing a speed of the vehicle and a service brake pedal position;   a processor determining an intent of the driver, based on the at least one input signal, to automatically apply the automatic work brake when the speed of the vehicle is less than a predetermined speed and the service brake pedal is depressed; and   an output delivering a control signal for automatically engaging the work brake based on the intent of the driver.   
     
     
         22 . The controller for an automatic work brake on a vehicle as set forth in  claim 21 , wherein:
 the processor determines the intent of the driver is to automatically release the work brake if the at least one input signal indicates a throttle demand of the engine is greater than a predetermined level.   
     
     
         23 . A system for automatically at least one of applying and releasing a work brake, the system comprising:
 means for determining whether to at least one of automatically apply and release the work brake; and   means for controlling pressure delivered to a service brake, the pressure being continuously fluidly communicated to the service brake for causing the service brake to act as the work brake when it is determined to automatically apply the work brake, and the pressure being not fluidly communicated to the service brake for releasing the work brake when it is determined to automatically release the work brake.   
     
     
         24 . The system for automatically at least one of applying and releasing a work brake as set forth in  claim 23 , further including:
 means for determining an intent of a driver;   the means for determining whether to automatically at least one of apply and release the work brake being based on the intent of the driver.   
     
     
         25 . A method controlling an automatic work brake on a vehicle, the method comprising:
 receiving at least one input signal indicative of a status of the vehicle representing at least one of a speed of the vehicle and a service brake pedal position;   determining to automatically apply the automatic work brake based on the at least one input signal; and   delivering a control signal for automatically applying the work brake based on the determination to automatically apply the automatic work brake.   
     
     
         26 . The method controlling an automatic work brake on a vehicle as set forth in  claim 25 , further including:
 determining an intent of the driver based on the at least one input signal.   
     
     
         27 . The method controlling an automatic work brake on a vehicle as set forth in  claim 25 , wherein the step of determining to automatically apply the automatic work brake includes:
 determining to automatically apply the automatic work brake when the speed of the vehicle is less than a predetermined speed and the service brake pedal is depressed.   
     
     
         28 . The method controlling an automatic work brake on a vehicle as set forth in  claim 25 , further including:
 determining to automatically release the automatic work brake when a throttle demand of the engine is above a predetermined level.