A vehicle suspension system incorporating suspension units (46-48) associated with respective vehicle wheels and selectively controllable to vary the ride height of the vehicle. Vehicle speed sensors and height sensors are responsive to departure of the ride height from a predetermined height datum which is a function of the vehicle speed and to provide a signal related thereto to control movement of at least one suspension unit thereby to tend to move at least a part of the vehicle to said predetermined height datum. Timer means are provided so that the movement of a suspension unit in response to a signal from a height sensor is inhibited until a signal of at least a predetermined magnitude has persisted for at least a prescribed part of a prescribed period of time.
In an air spring system of a motor vehicle having a pressure line extending between a compressor and a pressure storage or air springs of the motor vehicle, the pressure line includes a section between a dryer and the air springs with a variable flow cross-section and with one electromagnetically actuable switching valve arranged in parallel with the variable flow cross-section and providing unrestricted flow when opened.
An air suspension system for a load bearing vehicle which includes a pair of air springs fluidly connected to a pair of auxiliary air reservoirs and to a main air reservoir. The system includes control valves which permit the air in the air springs to be exhausted therefrom to lower the vehicle frame without exhausting the air from the auxiliary air reservoirs.
This invention pertains to an air compressor having a cylinder head with an air supply passage communicating with a discharge hole. First and second exhaust passages are arranged in parallel between the air supply passage and an exhaust port. A pilot-operated switching valve is located at an intermediate position in the first exhaust passage. A solenoid-operated exhaust valve is located at an intermediate position in the second exhaust passage. The solenoid-operated exhaust valve is selectively opened or closed by an externally supplied electric current, thereby controlling a pilot pressure applied to a valving element of the pilot-operated switching valve. The valving element is rested on or separated from a valve seat by the pilot pressure. The compressed air discharge speed can be increased without increasing the size of the cylinder head, and vehicle height adjustment, for example, can be made in a reduced period of time.
The invention relates to a level control arrangement for a vehicle having air springs (8) via which the chassis of the vehicle is suspended relative to at least one vehicle axle. A pneumatically-controllable directional-control valve (18) is arranged between the compressor (4) and the air dryer (6) and the directional-control valve (18) has two control inputs (20 and 22). In the base state of the level control arrangement, the compressor (4) is connected via the pneumatically-controllable directional-control valve (18) to the air dryer (6). When the control line (26) of the first control input (20) is connected via a controllable directional-control valve (30) to the atmosphere, the pneumatically-controllable directional-control valve 18 transfers into the other switching state and the air spring (8) can be vented via the air dryer (6). The pneumatically-controllable directional-control valve (18) permits large flow cross sections to be switched so that the air dryer (6) can be rapidly vented when venting the air spring (8) and a regeneration of the air dryer (6) is then possible in an especially advantageous manner.
In a method and a device of a motor vehicle, including regulating units for adjusting the level position of a motor vehicle, at least one control unit for activating the regulating units, at least one sensor mechanism for recording the actual level position of the motor vehicle and a device for setting a setpoint level position of the motor vehicle, the actual level position being adapted to the actual speed of the motor vehicle regarding driving dynamics, whereby a set setpoint level position is able to be fixed, a limiting speed V.sub.limit regarding driving dynamics is able to be assigned to the setpoint level position, and this limiting speed is not able to be exceeded.
