Load-based tire inflation system for heavy-duty vehicles

Abstract

A load-based tire inflation system for a heavy-duty vehicle comprises at least one source of fluid pressure, suspension structure of the heavy-duty vehicle, a tire and wheel assembly and a system to control fluid pressure in the tire and wheel assembly. The suspension structure is located between a frame member and an axle and has a condition indicative of a weight of the heavy-duty vehicle. The tire and wheel assembly is operatively mounted to the axle and is in fluid communication with the source of fluid pressure. The control system controls fluid pressure in the tire and wheel assembly in response to the condition of the suspension structure.

What is claimed is: 
     
         1 . A load-based tire inflation system for a heavy-duty vehicle comprising:
 at least one source of fluid pressure;   a suspension structure of the heavy-duty vehicle, the suspension structure having a condition indicative of a load of the heavy duty vehicle;   a tire and wheel assembly operatively mounted to an axle of the heavy-duty vehicle and in fluid communication with the at least one source of fluid pressure; and   means for controlling fluid pressure in the tire and wheel assembly in response to the condition of the suspension structure.   
     
     
         2 . The load-based tire inflation system of  claim 1  further including a first sensor to detect the condition of the suspension structure and a second sensor to detect a fluid pressure in the tire and wheel assembly, wherein the system to control fluid pressure operates in response to signals communicated from the first and second sensors. 
     
     
         3 . The load-based tire inflation system of  claim 1  further including the suspension structure having at least one member selected from the group consisting of a ride height control valve, a lift air bag, and an air spring. 
     
     
         4 . The load-based tire inflation system of  claim 3  where the suspension structure of the heavy-duty vehicle is in communication with the at least one source of fluid pressure. 
     
     
         5 . The load-based tire inflation system of  claim 4  where the condition of the suspension structure is a fluid pressure within an air spring of the suspension structure. 
     
     
         6 . The load-based tire inflation system of  claim 1  further including a regulator to establish a minimum pressure threshold, wherein fluid pressure in the tire and wheel assembly is maintained at or above the minimum pressure threshold. 
     
     
         7 . The load-based tire inflation system of  claim 1  wherein the means for controlling fluid pressure in the tire and wheel assembly continuously monitors fluid pressure in the suspension structure and varies fluid pressure in the tire and wheel assembly upon a change in fluid pressure in the suspension structure. 
     
     
         8 . The load-based tire inflation system of  claim 1  wherein the means for controlling fluid pressure in the tire and wheel assembly continuously adjusts tire pressure in response to fluid pressure in the air spring. 
     
     
         9 . The load-based tire inflation system of  claim 1  wherein the at least one source of fluid pressure is maintained at a constant pressure, the at least one source of fluid pressure being a conduit in selective fluid communication with the tire and wheel assembly. 
     
     
         10 . The load-based tire inflation system of  claim 1  wherein the means for controlling fluid pressure in the tire and wheel assembly includes an electronic control unit. 
     
     
         11 . The load-based tire inflation system of  claim 1  further including the suspension structure being located between a frame member of the heavy-duty vehicle and an axle of the heavy-duty vehicle. 
     
     
         12 . A load-based tire inflation system for a heavy-duty vehicle comprising:
 at least one source of fluid pressure;   at least one air spring connected to an axle of the heavy-duty vehicle and in fluid communication with the at least one source of fluid pressure, a fluid pressure in the at least one air spring being variable in response to change in a load carried by the heavy-duty vehicle;   a first tire and wheel assembly operatively mounted to the axle and being in fluid communication with the at least one source of fluid pressure; and   a means for increasing or decreasing pressure in the first tire and wheel assembly in response to changes in fluid pressure in the air spring.   
     
     
         13 . The load-based tire inflation system of  claim 12  further comprising a second tire and wheel assembly operatively mounted on an opposite end of the axle;
 wherein the means for increasing or decreasing pressure in the first tire and wheel assembly continuously varies fluid pressure in both the first and second tire and wheel assemblies on the axle. 
 
     
     
         14 . The load-based tire inflation system of  claim 13  further including a pair of air springs associated with the axle;
 a pair of sensors detecting fluid pressure in each of the pair of air springs; and 
 each of the pair of sensors communicating a signal to the means for increasing or decreasing pressure in the first tire and wheel assembly in response to the fluid pressure in the each of the pair of air springs. 
 
     
     
         15 . The load-based tire inflation system of  claim 12  wherein the at least one source of fluid pressure is maintained at a constant pressure, the at least one source of fluid pressure being a conduit in selective fluid communication with the first and second tire and wheel assemblies. 
     
     
         16 . The load-based tire inflation system of  claim 12  wherein the means for increasing or decreasing pressure in the first tire and wheel assembly includes an electronic control unit (ECU). 
     
     
         17 . A method of inflating tires of a heavy-duty vehicle with a load-based tire inflation system, the method comprising the steps of:
 providing at least one source of fluid pressure;   locating an air spring between a frame member of the heavy-duty vehicle and an axle of the heavy-duty vehicle;   fluidly connecting the air spring with the at least one source of fluid pressure, the air spring positioning the frame member relative to the axle as a function of a fluid pressure in the air spring;   determining the fluid pressure in the air spring which is an indication of a load of the heavy-duty vehicle;   mounting a tire and wheel assembly to the axle of the heavy-duty vehicle;   fluidly connecting the tire and wheel assembly with the at least one source of fluid pressure;   determining fluid pressure in the tire and wheel assembly; and   establishing fluid pressure in the tire and wheel assembly in response to the fluid pressure detected in the air spring.   
     
     
         18 . The method of inflating tires of a heavy-duty vehicle with a load-based tire inflation system of  claim 17  further comprising the steps of:
 determining a pressure differential between an air spring and a tire and wheel assembly; and 
 establishing fluid pressure in the tire and wheel assembly from the air spring as a function of the pressure differential between the air spring and tire and wheel assembly. 
 
     
     
         19 . A load-based tire inflation system for a heavy-duty vehicle comprising:
 an air spring to support a frame member relative to an axle in response to a load of the heavy duty vehicle;   a tire and wheel assembly operatively mounted to an axle of the heavy-duty vehicle;   means for determining a fluid pressure differential between the air spring and tire and wheel assembly; and   means for establishing fluid pressure in the tire and wheel assembly in response to the fluid pressure differential.   
     
     
         20 . The load-based tire inflation system of  claim 19  wherein the means for determining the fluid pressure is a pressure switch. 
     
     
         21 . A load-based tire inflation system for a heavy-duty vehicle comprising:
 at least one source of fluid pressure;   a suspension structure of the heavy-duty vehicle, the suspension structure having a condition indicative of a load of the heavy duty vehicle;   a tire and wheel assembly operatively mounted to an axle of the heavy-duty vehicle and in fluid communication with the at least one source of fluid pressure;   means for controlling fluid pressure in the tire and wheel assembly in response to the condition of the suspension structure, said controlling means including at least one electrical component; and   means for maintaining the tire and wheel assembly at a selected fluid pressure in the event electrical power is lost.