Method for regulating a compressed air supply system of a motor vehicle

Abstract

A method for regulating a compressed air supply system of a motor vehicle, the system having a driving engine for driving the motor vehicle, which can be switched via a switchable hydrodynamic coupling to a driven connection with an air compressor, so that the air compressor feeds a compressed air system via an air delivery side.

1 .- 13 . (canceled) 
     
     
         14 . A method for regulating a compressed air supply system of a motor vehicle, comprising:
 registering a pressure in the compressed air supply system;   comparing the pressure with a selected first minimum value;   filling a hydrodynamic coupling with a working medium when the pressure lies below the selected first minimum value and starting an air compressor;   connecting an air delivery side of the air compressor with the surroundings or with a low-pressure system for a selected period of time, depending on a revolutions per minute of the air compressor or of the hydrodynamic coupling and/or depending on the pressure; and   connecting the air delivery side of the air compressor with the compressed air supply system after conclusion of the selected period of time, when a selected revolutions per minute is reached and/or when the pressure is below a selected pressure value of a maximum counterpressure that is smaller than a selected first minimum pressure.   
     
     
         15 . The method according to  claim 14 , further comprising:
 comparing the pressure with the selected pressure value during start-up of the air compressor; and   connecting the air delivery side of the air compressor to the compressed air system when the pressure is equal to or smaller than the maximum counterpressure so that a feeding into the compressed air system ensues.   
     
     
         16 . The method according to  claim 14 , further comprising:
 comparing the pressure with the selected pressure value during start-up of the air compressor; and   connecting the air delivery side of the air compressor with the surroundings or with a low-pressure system when the pressure is greater than the maximum counterpressure.   
     
     
         17 . The method according to  claim 14 , further comprising:
 disposing a relay valve in an air-conducting line between the air compressor and the compressed air system; and   switching the relay valve so that the air compressor feeds compressed air into the compressed air system.   
     
     
         18 . The method according  claim 14 , further comprising connecting a relay valve to the hydrodynamic coupling so that a working medium can be introduced into a working chamber of the hydrodynamic coupling, the relay valve opening and closing a connection so that filling of the hydrodynamic coupling can be controlled. 
     
     
         19 . The method according to  claim 18 , further comprising emptying the hydrodynamic coupling so that the air compressor no longer feeds air into the compressed air system when the pressure lies above the selected maximum value. 
     
     
         20 . The method according to  claim 19 , further comprising:
 introducing a 2/3-directional control valve into the connection;   switching the 2/3-directional control valve to a first state in which the connection is opened when the pressure in the compressed air system lies below the selected first minimum value and the air compressor is operating at a revolutions per minute below or equal to a maximum allowable speed;   switching the 2/3-directional control valve to a second state in which the 2/3-directional control valve is shut-off when the pressure lies above the selected maximum value; and   switching the 2/3-directional control valve to a third state in which the 2/3-directional control valve is in a throttling position when the pressure lies below the selected maximum value and the air compressor operates at a revolutions per minute above a maximum allowable revolutions per minutes.   
     
     
         21 . The method according to  claim 20 , further comprising interrupting the connection when the pressure lies above a selected maximum pressure. 
     
     
         22 . The method according to  claim 21 , wherein the interrupting step comprises switching a position of the relay valve. 
     
     
         23 . The method according to  claim 21 , wherein the interrupting step comprises a time delay after the beginning of emptying of the hydrodynamic coupling. 
     
     
         24 . The method according to  claim 14 , further comprising:
 registering a speed of the motor vehicle; and   comparing the pressure with a selected second minimum value that lies below the selected first minimum value, the second minimum value representing a spring-loaded actuator triggering pressure of a braking system of the motor vehicle above which the motor vehicle must travel at a speed greater than zero, the pressure being below the selected second minimum value, wherein the revolutions per minute of a driving engine is increased.   
     
     
         25 . The method according to  claim 24 , further comprising:
 constantly filling the hydrodynamic coupling with the working medium when rotary power is transmitted from wheels of the motor vehicle to an engine driven shaft; and   venting compressed air from the compressed air system when the pressure exceeds the selected maximum value in order to limit the maximum pressure.   
     
     
         26 . The method according to  claim 25 , further comprising increasing the pressure on the air delivery side to a selected value by a shut-off valve or a throttle. 
     
     
         27 . The method according to  claim 14 , further comprising:
 registering or storing in memory a topography of a road on which the motor vehicle travels;   setting the selected minimum value or a selected third minimum value depending on the topography; and   starting the air compressor by filling the hydrodynamic coupling when the selected minimum value is not reached and when, simultaneously, the selected third minimum value is not reached.   
     
     
         28 . The method according to  claim 27 , wherein the setting step comprises setting the selected minimum value or a selected third minimum value depending on road- and travel-specific data recorded and stored in memory during earlier travels of the motor vehicle.