An air management system including at least one air spring and a compressor. The compressor defines a compartment having an inlet and an outlet. A reservoir is fluidly connected to the air spring and the compressor. A piston is moveable in the compartment and is reciprocally moveable in a compression stroke and an extension stroke in response to actuation of the motor in order to build-up air pressure at the outlet. The piston defines at least one passage extending between the extension chamber and the compression chamber, and at least one check valve positioned in the at least one passage such that air pressure in the compression chamber biases the piston toward the extension chamber to reduce a torque load on the motor during movement of the piston.

A process for correcting longitudinal roll from an offset load using active roll control within a vehicle is provided. The process includes, within a computerized controller using axle-based control to control a suspension system, operating programming to control pneumatic pressure supplied to each of a plurality of air spring devices within the suspension system to execute a vehicle leveling event including one of adjusting a height of the vehicle or maintaining the height of the vehicle. The process further includes operating programming to, simultaneously with the controlling the pneumatic pressure, utilize a plurality of active sway bars to provide an offset torque to the vehicle body. Each of the plurality of active sway bars is associated with one of a plurality of axles. Providing the offset torque is based upon a number of moles of air in each of the plurality of air spring devices and reducing the longitudinal roll.

In a pneumatically sprung vehicle (1) with a front steering axle (A), one rear drive axle (TA) and one trailing axle (SA), traction is controlled by an air suspension system (36), having a “pressure ratio control” mode maintaining a parametrised ratio of air pressures in supporting bellows (2, 4) of the drive axle (TA) compared to air pressures in supporting bellows (3, 5) of the trailing axle (SA); a “relieve loading of trailing axle” mode checking whether relieving of the loading of the trailing axle (SA) is possible without overloading the drive axle (TA); and an “optimum traction” control mode increasing the pressure in the supporting bellows (2, 4) of the drive axle (TA) and reducing the pressure in the supporting bellows (3, 5) of the trailing axle (SA) without exceeding the maximum permissible axle load of the drive axle (TA) while maintaining residual pressure of the trailing axle (SA).

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 suspension control system (ECAS, electronic controlled air suspension) (10) for a utility vehicle, such as a truck or the like, or for a passenger car, includes a main control unit (12) for operating the air suspension control system (10)and at least two auxiliary control units (14) connected to the main control unit (12) via a data link (16). The auxiliary control units (14) each have at least one output (18) for actuating at least one actuator (20) which can be connected to the output (18), in particular an adjustment drive (28) for a valve (30). Furthermore, at least one function for generating control signals at the output (18) can be stored in the auxiliary control units (14), and the main control unit (12) is adapted to call up and/or to parameterize at least the stored functions by transmitting commands via the data link (16).

A method for operating a pressure control system having a multistage compressor includes providing, by the multistage compressor, a pressure medium that has been compressed multiple times in order to fill a pressure medium reservoir or pressure medium chambers of the pressure control system. The providing the pressure medium involves providing, by a first compression stage, a precompressed pressure medium and additionally compressing, via a second compression stage, the precompressed pressure medium, and/or introducing an already compressed charge pressure medium into an intermediate volume between the first compression stage and the second compression stage of the multistage compressor and further compressing, by the second compression stage, the charge pressure medium. The charge pressure medium simultaneously passes, via a control line, to a control input of a shut-off valve that interacts with the first compression stage, such that a charge pressure of the charge pressure medium predefines a control pressure.

A vehicle height adjusting device includes a vehicle height adjusting unit, a prediction unit, and a vehicle height control unit. The vehicle height adjusting unit adjusts a vehicle height to one of a first state and a second state. In the first state, the vehicle height is set to a predetermined height, and in the second state, the vehicle height is set lower than the first state. The prediction unit predicts whether a drive battery (lower portion) of a vehicle interferes with a road surface in the second state. The vehicle height control unit controls the vehicle height adjusting unit to set the vehicle height to one of the first state and the second state. When the prediction unit predicts an interference between the drive battery of the vehicle and the road surface, the vehicle height adjusting unit restricts a transition from the first state to the second state.

An air suspension system which includes the ability to adjust the working air volume, pressure, and spring rate of one or more air springs to reduce or eliminate various types of vehicle oscillations. Switchable or variable volume air spring assemblies have the ability to change air spring volumes, which results in changes in air spring rates, and therefore changes in normal loads applied to each wheel. Changes in wheel normal loads change wheel traction (slip) and vehicle dynamics (pitch, roll, yaw displacement, rate and acceleration). The spring rate of one or more of the air spring assemblies is adjusted automatically when a vehicle oscillation is detected. This vehicle oscillation is calculated from the raw vehicle signals, or another vehicle module may detect the oscillation and send a command to the air suspension module to change the spring rates. This changes the natural frequency of the vehicle, dampening the oscillation.

An air suspension system which includes a Dynamic Load Transfer (DLT) function. DLT is a process of transferring vehicle load, or varying normal loads applied to each wheel of the vehicle, using switchable volume or variable volume air spring assemblies. Switchable or variable volume air spring assemblies have the ability to change air spring volumes, which results in changes in air spring rates, which result in changes in normal loads applied to each wheel. Changes in wheel normal loads change wheel traction (slip) and vehicle dynamics (pitch, roll, yaw displacement, rate and acceleration). Each air spring assembly may have multiple volume air chambers that are switched “on” and “off,” a variable volume air chamber, or the air spring assembly may be coupled with other air springs, or air chambers, that are switched or varied.

A vehicle fluid spring system is adapted to absorb road shock imparted onto at least one road wheel of a vehicle. The vehicle fluid spring system includes a fluid spring and a variable volume unit. The fluid spring includes a fluid chamber adapted to change in volume. The variable volume unit including a rigid piston cylinder, a piston, a fluid cavity, and an actuator. The piston is adapted to reciprocate within, and is in sliding contact with, the rigid piston cylinder. The fluid cavity is defined by the piston cylinder and the piston. The actuator is adapted to drive the piston changing a volume of the fluid cavity. The fluid cavity is in fluid communication with the fluid chamber.