Pressure control process and apparatus

• US 5,782,541 A
• Filed: 08/09/1995
• Issued: 07/21/1998
• Est. Priority Date: 08/16/1994
• Status: Expired due to Term

• Current Assignee: Wabco Vermogensverwaltung GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Wabco Vermogensverwaltung GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Schappler, Harmut
• Primary Examiner(s): Young, Lee W.
• Application Number:
  US08/512,944
• Time in Patent Office: 1,077 Days
• Field of Search: 303/3, 303/15, 303/20, 303/119.1, 303/155, 303/199, 364/426.02
• US Class Current: 303/3
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components

Abstract

A process and an apparatus for pressure control, in particular, to adjust braking pressures in a utility vehicle, are proposed. Two individual controllers (10, 11) are assigned respectively to an inlet valve (2) and to a discharge valve (3). A pilot control value consisting of a fixed value y_v and of a memorized value Δy_v is additively input to the output values of these controllers. The memorized components Δy_v are the integration result of the I (integration) components of the individual controllers (10, 11) for the duration of a pressure increase (inlet valve) or pressure decrease (discharge valve). The memorizing process is ended after approximately five to ten brake applications and the value of Δy_v which is then reached is used as an individual pilot control value.

Claims

1. Pressure control process in a braking system of a vehicle, comprising the steps of:

transmitting a command variable from a driver to a controller of at least one valve, said at least one valve having an operating point,

determining said operating point of said at least one valve with a pilot control value during a series of brake cycles, said pilot control value consisting additively of a constant value and a variable value,

determining a new variable value after each of said brake cycles,

storing said new variable value after each of said brake cycles,

determining said variable value based on said new variable values, stored for each of said brake cycles,

updating said pilot control value with said variable value, and

controlling said at least one valve with said pilot control value.

2. Process as in claim 1, wherein

said controller has an integration component, and

said variable component is calculated as the integration result of said integration component of said controller for the duration of a pressure change for said at least one valve.

3. Process as in claim 2, wherein said pilot control valve is determined in less than ten brake cycles.

4. Process as in claim 1, wherein said storing of said new variable value is carried out only when the said command variable changes at a rate between 0.25 bar/s and 2 bar/s.

5. Process as in claim 1, wherein said storing of said new variable value is carried out only when said command variable is between 0.5 bar and 6 bar.

6. Process as in claim 1, wherein said braking system has an ABS, and

said storing of said new variable value is not carried out when said ABS is activated.

7. Process as in claim 1, further comprising monitoring operation of said braking system by receiving characteristic values of said braking system, and storing of said new variable value is not carried out.

8. Process as in claim 1, wherein said valve has an operating voltage, and

said storing of said new variable value is not carried out if said operating voltage is insufficient.

9. Process as in claim 1, wherein said at least one valve has an operating voltage, and

said pilot control value is stored in a non-volatile memory module each time said operating voltage is switched off and said stored pilot control value is used as said pilot control value at the next start of the vehicle.

10. Process as in claim 1, said process further comprising the steps of

monitoring said variable value,

declaring a valve error if said monitored variable value deviates significantly from a normal variable value,

connecting an integration component of said controller to an adaptation device, said integration component of said controller having an integration constant, said adaptation device designed as an integrator having an integration constant less than said integration constant of said controller,

transmitting said command variable and an output signal of a pressure phase detector to said adaptation device, and

additively connecting an output of said adaptation device and an output of said controller and said pilot control value.

11. Process as in claim 1, wherein said braking system has an ASR, and

said storing of said variable value is not carried out when said ASR is activated.

12. Process as in claim 1, wherein said brake system further having an operating voltage, and

said pilot control value is stored in a non-volatile memory at fixed intervals, and that said stored pilot control value is used first at the next start of the vehicle.