Tire pressure monitoring method

Abstract

A method of monitoring the fluid pressure of, with a sensor of a tire pressure management system disposed without, a tire that prevents overinflation of same. The method of monitoring a fluid pressure of a tire with a sensor, disposed in conduit assemblies for conducting fluid to or from the tire, of a tire pressure management system includes providing a pulse of compressed fluid to the conduit assemblies, unless a counter exceeds a count, the fluid in the conduit assemblies thereafter having a conduit pressure. The pulse has a duration that corresponds to a ratio defined by a first predetermined amount divided by a second predetermined amount.

1. A method of determining a tire pressure in a vehicle tire comprising the steps of:
 ascertaining a first fluid pressure in a conduit disposed between a fluid source and said tire using a sensor disposed in said conduit;  
 comparing said first fluid pressure to a target pressure;  
 providing a pulse of compressed fluid to said conduit when said first fluid pressure is less than said target pressure, said pulse having a duration determined responsive to a duration of a previous pulse of compressed fluid provided to said conduit and a change in pressure in said conduit resulting from said previous pulse; and,  
 repeating said ascertaining, comparing, and providing steps until said first fluid pressure in said conduit reaches said target pressure.  
 
     
     
       2. The method of  claim 1  wherein said first fluid pressure is ascertained following a predetermined hold time that begins after said previous pulse is provided to said conduit. 
     
     
       3. The method of  claim 1  wherein said duration of said previous pulse is a preset period. 
     
     
       4. The method of  claim 1  wherein said duration of said pulse is determined in accordance with the following formula:
   D 1 =n*D 0 *[(P l −temp 1 )/(temp1−P L )] 
 wherein n is a predetermined value, D 0  is said duration of said previous pulse, P T  is said target pressure, temp1 is said first fluid pressure and P L  is a previous fluid pressure in said conduit resulting from said previous pulse.  
 
     
     
       5. The method of  claim 1  further comprising the steps of:
 determining a second fluid pressure in said conduit following a predetermined line leak hold time; and,  
 comparing said first and second fluid pressures.  
 
     
     
       6. The method of  claim 5  wherein said tire pressure equals said first fluid pressure if a difference between said first and second fluid pressures is less than a predetermined amount. 
     
     
       7. The method of  claim 5  further comprising the step of logging a line leak fault if a difference between said first and second fluid pressures is greater than a predetermined amount. 
     
     
       8. A method of determining a tire pressure in a vehicle tire comprising the steps of:
 ascertaining a first fluid pressure in a conduit disposed between a fluid source and said tire using a sensor disposed in said conduit;  
 comparing said first fluid pressure to a target pressure; incrementing a counter when said first fluid pressure is less than said target pressure;  
 comparing said counter to a predetermined value;  
 providing a pulse of compressed fluid to said conduit when said first fluid pressure is less than said target pressure and said counter is less than said predetermined value, said pulse having a duration determined responsive to a duration of a previous pulse of compressed fluid provided to said conduit and a change in pressure in said conduit resulting from said previous pulse; and,  
 repeating said ascertaining, comparing, and providing steps until said first fluid pressure in said conduit reaches said target pressure or said counter reaches said predetermined value.  
 
     
     
       9. The method of  claim 8  wherein said first fluid pressure is ascertained following a predetermined hold time that begins after said previous pulse is provided to said conduit. 
     
     
       10. The method of  claim 8  wherein said duration of said previous pulse is a preset period. 
     
     
       11. The method of  claim 8  wherein said duration of said pulse is determined in accordance with the following formula:
   D 1 =n*D 0 *[(P T −temp1)/(temp1−P L )] 
 wherein n is a predetermined value, D 0  is said duration of said previous pulse, P T  is said target pressure, temp1 is said first fluid pressure and P L  is a previous fluid pressure in said conduit resulting from said previous pulse.  
 
     
     
       12. The method of  claim 8 , further comprising the steps of:
 determining a second fluid pressure in said conduit following a predetermined line leak hold time; and,  
 comparing said first and second fluid pressures.  
 
     
     
       13. The method of  claim 12  wherein said tire pressure equals said first fluid pressure if a difference between said first and second fluid pressures is less than a predetermined amount. 
     
     
       14. The method of  claim 12  further comprising the step of logging a line leak fault if a difference between said first and second fluid pressures is greater than a predetermined amount. 
     
     
       15. A system for determining whether a vehicle tire is at a target pressure, comprising:
   a conduit disposed between a fluid tank on said vehicle and said vehicle tire;        a first valve disposed between said fluid tank and said conduit;        a sensor in fluid communication with said conduit and generating a fluid pressure signal indicative of fluid pressure in said conduit;        an electronic control unit configured to perform a control operation in which said unit controls said first valve to introduce a pulse of compressed fluid into said conduit, a determination operation in which said unit determines a fluid pressure in said conduit responsive to said fluid pressure signal, a comparison operation in which said unit compares said fluid pressure in said conduit to a target pressure, and a repeat operation in which said unit repeats said control, determination, and compare operations if said fluid pressure in said conduit does not meet a first predetermined condition relative to said target pressure.     
     
     
       16. The system of  claim 15  wherein said electronic control unit is further configured to perform an update operation in which said unit updates a value of a counter if said fluid pressure does not meet said first predetermined condition relative to said target pressure. 
     
     
       17. The system of  claim 16  wherein said electronic control unit is further configured to determine whether said value of said counter meets a second predetermined condition. 
     
     
       18. The system of  claim 17  wherein said electronic control unit is further configured to reset said counter to a predetermined value if said value of said counter meets said second predetermined condition. 
     
     
       19. The system of  claim 16  wherein said electronic control unit is further configured to perform said update operation prior to said repeat operation. 
     
     
       20. The system of  claim 15  wherein said electronic control unit is further configured to perform said determination operation after a predetermined hold time following said control operation. 
     
     
       21. The system of  claim 15  wherein said pulse has a predetermined duration. 
     
     
       22. The system of  claim 15  wherein said first valve is a solenoid valve. 
     
     
       23. The system of  claim 15 , further comprising a second valve disposed between said first valve and said vehicle tire. 
     
     
       24. The system of  claim 23  wherein said second valve is a solenoid valve. 
     
     
       25. The system of  claim 23  wherein said electronic control unit is configured to control said second valve. 
     
     
       26. The system of  claim 23  wherein said second valve is configured to selectively vent said conduit. 
     
     
       27. The system of  claim 15 , further comprising a rotary seal assembly disposed between said conduit and said vehicle tire. 
     
     
       28. A method for determining whether a vehicle tire is at a target pressure, comprising the steps of:
   controlling a first valve disposed between a fluid tank on said vehicle and a conduit that is disposed between said fluid tank and said tire to introduce a pulse of compressed fluid into said conduit;        determining a fluid pressure in said conduit responsive to a fluid pressure signal generated by a sensor in fluid communication with said conduit, said fluid pressure signal indicative of fluid pressure in said conduit;        comparing said fluid pressure in said conduit to a target pressure;        providing a pulse of compressed fluid to said conduit when said fluid pressure is less than said target pressure; and,        repeating said controlling, determining, and comparing steps if said fluid pressure in said conduit does not meet a first predetermined condition relative to said target pressure.     
     
     
       29. The method of  claim 28 , further comprising step of updating a value of a counter if said fluid pressure does not meet said first predetermined condition relative to said target pressure. 
     
     
       30. The method of  claim 29 , further comprising the step of determining whether said value of said counter meets a second predetermined condition. 
     
     
       31. The method of  claim 30 , further comprising the step of resetting said counter to a predetermined value if said value of said counter meets said second predetermined condition. 
     
     
       32. The method of  claim 29  wherein said updating step occurs prior to said repeating step. 
     
     
       33. The method of  claim 28  wherein said determining step is performed after predetermined hold time following said controlling step. 
     
     
       34. The method of  claim 28  wherein said pulse has a predetermined duration. 
     
     
       35. The method of  claim 28  wherein said first valve is a solenoid valve. 
     
     
       36. The method of  claim 28 , further comprising the step of controlling a second valve disposed between said first valve and said tire. 
     
     
       37. The method of  claim 36  wherein said second valve is a solenoid valve. 
     
     
       38. The method of  claim 36  wherein said second valve is configured to selectively vent said conduit.