Electronic compressed air system
An electronic compressed air system for vehicles includes a compressed air supply part having a compressor, a compressed air consumer part having load circuits forming an air-suspension circuit, and service-brake circuits having reservoirs. The load circuits are supplied with compressed air via solenoid valves. The pressure in the load circuits is monitored by pressure sensors whose signals are evaluated by an ECU that controls the solenoid valves. The solenoid valve of the air-suspension circuit does not include reservoirs and is closed in the de-energized normal state. The solenoid valves of other load circuits, especially of the service-brake circuits are open in the de-energized normal state. With a pressure demand of the air-suspension circuit, the associated solenoid valve is switched by the ECU to open position to establish communication with the compressed air supply part and/or with the service-brake circuits or with the reservoirs thereof, to refill the air-suspension circuit.
1. An electronic compressed air system for a vehicle comprising:
a compressed air supply part including a compressor; and
a compressed air consumer part, said compressed air consumer part including:
a plurality of service-brake circuits having compressed air load circuits and compressed air reservoirs;
a high pressure compressed air load circuit;
electrically actuatable valves comprising a first plurality of electrically actuatable valves and at least one other electrically actuatable valve, said first plurality of electrically actuatable valves being operable to supply compressed air to said plurality of service-brake circuits, said at least one other electrically actuatable valve being operable to supply compressed air to said high pressure compressed air load circuit, and said first plurality of electrically actuatable valves being in an open position in a de-energized condition during normal driving;
sensors for monitoring pressure in said plurality of service-brake circuits; and
an electronic control unit configured to evaluate electrical signals from said sensors and to control said electrically actuatable valves, said at least one other electrically actuatable valve operable to supply compressed air to said high pressure compressed air load circuit being switchable by said electronic control unit between a closed position in a de-energized condition during normal driving and an open position to establish communication between said at least one other electrically actuatable valve with at least one of (i) said service-brake circuits (ii) said compressed air reservoirs and (iii) said compressed air supply part, when compressed air is requested for said high pressure compressed air load circuit.
2. The compressed air system according to claim 1 , wherein said high pressure compressed air load circuit is an air-suspension circuit.
3. The compressed air system according to claim 1 , wherein said electronic control unit is adapted to iteratively (i) close said at least one other electrically actuatable valve operable to supply compressed air to said high pressure compressed air load circuit and turn on said compressor to refill said plurality of service-brake circuits when a state variable in said plurality of service-brake circuits drops below a preselected value, (ii) reopen said at least one other electrically actuatable valve operable to supply compressed air to said high pressure compressed air load circuit when an index value is reestablished in said plurality of service-brake circuits, and, thereafter, when said high pressure compressed air load circuit reaches said index value, switch said at least one other electrically actuatable valve to a closed normal state and turn off said compressor.
4. The compressed air system according to claim 1 , wherein said electrically actuatable valves are solenoid valves.
5. The compressed air system according to claim 1 , further comprising an electronic control device adapted to control said high pressure compressed air load circuit and to communicate with said electronic control unit via a data line.
6. The compressed air system according to claim 5 , wherein said data line is operable to carry a compressed air demand transmission to said electronic control device.
7. The compressed air system according to claim 1 , wherein said compressed air load circuits have at least one secondary load circuit without compressed air reservoirs.
8. The compressed air system according to claim 7 , wherein said at least one secondary load circuit has a lower pressure level than in said service-brake circuits.
9. The compressed air system according to claim 7 , wherein said high pressure compressed air load circuit has a pressure level that is higher than in said service-brake circuits and in said at least one secondary load circuit.
10. The compressed air system according to claim 7 , wherein said at least one secondary load circuit includes solenoid valves, and further comprising a pressure-limiting valve interposed upstream from said solenoid valves of said at least one secondary load circuit.
11. The compressed air system according to claim 1 , wherein said electrically actuatable are connected to a common compressed air distributor line, to which there is connected a compressed air supply line in communication with said compressor.
12. The compressed air system according to claim 11 , further comprising an air dryer and a check valve disposed in said compressed air supply line.
13. The compressed air system according to claim 3 , wherein said state variable is one of pressure, air flow rate, air mass and energy.