Deflation control system and method

• US 5,249,609 A
• Filed: 12/14/1990
• Issued: 10/05/1993
• Est. Priority Date: 07/25/1988
• Status: Expired due to Term

• Current Assignee: Dana Heavy Vehicle Systems Group LLC (Dana, Inc.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Walker, James M., Ruzicka, L. Michael, Beverly, James
• Primary Examiner(s): Recla, Henry J.
• Assistant Examiner(s): JACYNA, J CASIMER
• Application Number:
  US07/629,043
• Time in Patent Office: 1,026 Days
• Field of Search: 141/1, 141/4, 141/38, 141/39, 141/47, 141/66, 141/83, 141/94, 141/95, 141/192, 141/197, 152/415-417, 340/442, 73/146-146.5, 137/12, 137/14, 137/224, 137/224.5
• US Class Current: 141/4
• CPC Class Codes: B60C 23/00354 Details of valves
• CPC Class Codes: B60C 23/00372 characterised by fluid diagrams

Abstract

A control system and method for controlling deflation operations in a CTIS (10, 200). During deflation to a selected pressure (P_D), the tires will be deflated to a target pressure (P_T) lower than the selected pressure and then inflated to the selected pressure.

Claims

1. A method for simultaneously controlling the inflation pressure of a plurality of fluidly separable inflatable tires, said method comprising the steps of:

a. providing a central tire inflation system including an operator'"'"'s control device (102) for selection of one of a plurality of selectable desired inflation pressures, a connection to a source of pressurized fluid, an exhaust means, a selectively pressurized and exhausted conduit, said conduit pressurized by said source to a single positive pressure greater than any of said selectable desired inflation pressures or to a single positive pressure lower than any of said selectable desired inflation pressures, tire valves (32,

     34) at each of said tires, said tire valves automatically responsive to pressurization of said conduit to simultaneously connect the interior pressure chambers of all of said tires of said conduit pressurized to said single positive pressure lower than any of said selectable desired inflation procedures, to connect the interior pressure chambers of all of said tires to said conduit pressurized to said single positive pressure greater than any of said selectable desired inflation pressures or to seal said interior pressure chambers, a pressure transducer remote from the inflatable tires and a central processing unit (88) for receiving input signals from said pressure transducer and said control device and for processing same in accordance with predetermined logic rules to issue command output signals to control the pressurization of said conduit;

b. sensing the selected desired inflation pressure of the inflatable tires;

c. exposing the pressure transducer to a fluid pressure substantially equal to the inflation pressure of one of said tires to measure and store an initial inflation pressure value;

d. comparing the initial inflation pressure value to the desired pressure value;

e. if said initial inflation pressure value exceeds said desired pressure value,

(i) calculating a target pressure value having a value less than said desired pressure value;

(ii) then causing in sequence the interior pressure chambers of all of said inflatable tires to be connected to the conduit pressurized to said single positive pressure lower than any of said selectable desired inflation pressures and then exposing the pressure transducer to a fluid pressure equal to the inflation pressure of one of said tires to measure an updated pressure value until the updated measured inflation pressure value is substantially equal to said target pressure value, and

(iii) then causing the interiors of all of said tires to be connected to said conduit pressurized to said single positive pressure greater than any of said selectable desired inflation pressures until the measured inflation pressure value substantially equals said selected desired pressure value.

2. The method of claim 1 wherein said target inflation value is in the range of two-to-five psi less than said selected desired pressure value.

3. The method of claim 1 wherein said one of said inflatable tires is the tire having the lower inflation pressure at the time of measurement.