An air suspension system capable of raising both the vehicle front wheel side and the vehicle rear wheel side by using a single tank. The air suspension system (1) includes a front wheel-side air suspension (2) and a rear wheel-side air suspension (7) which are interposed between a vehicle body and associated axles to perform vehicle height adjustment in response to supply and discharge of air, a compressor (17) for compressing air, and a tank (27) for storing air compressed by the compressor. When the vehicle height is to be raised by the air suspensions, the front wheel-side air suspension is supplied with compressed air from the tank, and the rear wheel-side air suspension is supplied with compressed air from the tank after the compressed air has been pressurized by the compressor.

Provided is a closed type air suspension apparatus requiring no complicated control and capable of simplifying the overall structure. The air suspension apparatus includes a tank storing air, a return valve returning compressed air in an air suspension to the tank, a discharge valve discharging compressed air in the tank to the outside through an intake-discharge port when the compressed air between the intake side of a compressor body and the tank reaches a first value or more, and an intake valve opening when the pressure of the air between the intake side of the compressor body and the tank is at a second value less than the first value, thereby allowing the atmosphere (air) to be taken in from the intake-discharge port. The compressor body of a compressor compresses air including the compressed air in the tank.

A compressed-air feed system for operating a pneumatic system includes a compressed-air supply, a compressed-air connection to the pneumatic system, a ventilation connection to surroundings, and a pneumatic main line between the compressed-air supply and the compressed-air connection. The pneumatic main line has an air dryer and a regeneration throttle. The compressed-air feed system further includes a ventilation line between the pneumatic main line and the ventilation connection. The ventilation line has a ventilation valve and a ventilation throttle. The compressed-air feed system further includes a bypass line between the compressed-air connection and the air dryer. The bypass line has a bypass valve formed as a 2/2 directional valve configured to permit an air flow conducted via the air dryer, and bypassing the regeneration throttle, for filling and ventilating the pneumatic system.

An air management system for a vehicle having a supply tank, a system controller integrated with the supply tank, a first pneumatic circuit pneumatically connected to the system controller, and a second pneumatic circuit pneumatically connected to the system controller. The system controller adjusts independently air pressure of the first pneumatic circuit and the second pneumatic circuit without establishing pneumatic communication between the first and second pneumatic circuits. The system controller establishes pneumatic communication between the first and second pneumatic circuits when the system controller is not adjusting independently the air pressure of the first pneumatic circuit and the second pneumatic circuit.

A compressed-air feed system for operating a pneumatic system includes a compressed-air supply, a compressed-air connection to the pneumatic system, at least one ventilation connection to surroundings, and a pneumatic main line between the compressed-air supply and the compressed-air connection. The pneumatic main line has an air dryer and a regeneration throttle. The compressed-air feed system further includes a first ventilation line between the pneumatic main line and the at least one ventilation connection. The first ventilation line has a first ventilation valve and a ventilation throttle. The compressed-air feed system additionally includes a second ventilation line between the compressed-air connection and the at least one ventilation connection. The second ventilation line has a second ventilation valve formed as a 2/2 directional valve. The compressed-air feed system is designed to provide an operating mode in which the second ventilation valve is open over a predetermined time period.

An air management system for a vehicle having a supply tank, a system controller integrated with the supply tank, a first pneumatic circuit pneumatically connected to the system controller, and a second pneumatic circuit pneumatically connected to the system controller. The system controller adjusts independently air pressure of the first pneumatic circuit and the second pneumatic circuit without establishing pneumatic communication between the first and second pneumatic circuits. The system controller establishes pneumatic communication between the first and second pneumatic circuits when the system controller is not adjusting independently the air pressure of the first pneumatic circuit and the second pneumatic circuit.

An air management system for a vehicle having a first pneumatic circuit and a second pneumatic circuit, in which the first and second pneumatic circuits are pneumatically connected in a neutral position via a cross-flow mechanism. The first pneumatic circuit includes a first leveling valve configured to adjust independently the height of a first side of the vehicle. The second pneumatic circuit includes a second leveling valve configured to adjust independently the height of a second side of the vehicle. The first and second leveling valves are configured to establish pneumatic communication between the first and second pneumatic circuits when the first leveling valve is not independently adjusting the height of the first side of the vehicle and the second leveling valve is not independently adjusting the height of the second side of the vehicle.

An air management system for a vehicle having a first pneumatic circuit and a second pneumatic circuit, in which the first and second pneumatic circuits are pneumatically connected in a neutral position via a cross-flow mechanism. The first pneumatic circuit includes a first leveling valve configured to adjust independently the height of a first side of the vehicle. The second pneumatic circuit includes a second leveling valve configured to adjust independently the height of a second side of the vehicle. The first and second leveling valves are configured to establish pneumatic communication between the first and second pneumatic circuits when the first leveling valve is not independently adjusting the height of the first side of the vehicle and the second leveling valve is not independently adjusting the height of the second side of the vehicle.

An air management system for a vehicle having a first pneumatic circuit and a second pneumatic circuit, in which the first and second pneumatic circuits are pneumatically connected in a neutral position via a cross-flow mechanism. The first pneumatic circuit includes a first leveling valve configured to adjust independently the height of a first side of the vehicle. The second pneumatic circuit includes a second leveling valve configured to adjust independently the height of a second side of the vehicle. The first and second leveling valves are configured to establish pneumatic communication between the first and second pneumatic circuits when the first leveling valve is not independently adjusting the height of the first side of the vehicle and the second leveling valve is not independently adjusting the height of the second side of the vehicle.

A leveling valve (101) for discharging and supplying air from and to a plurality of utilization elements (205a,b), in particular pneumatic suspension bellows, includes a valve arrangement (103) for directing air between a source (207) of pressurized air, an exhaust port (3) and the utilization elements (205a,b), and a supply port (1) in fluid communication with the valve arrangement (103) and the source (207) of pressurized air. A check valve (5) is mounted upstream of the valve arrangement (103) and is configured to allow fluid flow from the supply port (1) towards the valve arrangement (103) and to block fluid flow from the valve arrangement (103) through the supply port (1).