A pump system includes a housing defining a first internal volume and a second internal volume, a first piston positioned to separate the first internal volume into a first chamber and a second chamber, a second piston positioned to separate the second internal volume into a third chamber and a fourth chamber, a directional control valve (DCV) fluidly coupled to the second chamber and the fourth chamber, a first relief valve fluidly coupled to the DCV via a first control line and the second chamber via a first sensing line, a first orifice positioned along the first sensing line, a second relief valve fluidly coupled to the DCV via a second control line and the fourth chamber via a second sensing line, and a second orifice positioned along the second sensing line.

An apparatus for estimating vehicle weight using a vehicle height adjusting device is provided. The apparatus includes a vehicle height adjusting device that raises or lowers four positions of front left (FL) and right (FR) sides and rear left (RL) and right (RR) sides of a vehicle body, respectively. A vehicle height controller operates the vehicle height adjusting device to raise or lower the FL and FR sides and the RL and RR sides of the vehicle body. A weight estimating unit measures time required for raising or lowering the vehicle body or operating speed of the vehicle body and calculates an expected vehicle weight value by comparing the time required or the operating speed with a preset reference data.

Methods and systems are provided for a vehicle suspension system. In some example methods, a height change request is received for a vehicle suspension having a displacement control for implementing height change requests. A displacement of at least one spring of the vehicle suspension may be determined, as well as whether the displacement satisfies a displacement control criteria. The height of the vehicle suspension may be changed using an air mass control in response to determining the displacement control criteria is not satisfied.

Example illustrations are directed to a suspension system for a vehicle, which includes a controller configured to determine a roughness of a ground surface associated with the vehicle. The controller may be further configured to determine a height adjustment parameter for the suspension system based on the roughness determined, and to facilitate modification of the suspension system based on the determined height adjustment parameter. Example methods are provided, which may include determining, using a controller, a roughness of a ground surface associated with a vehicle, the roughness determined based on ride height. The method may also include determining, using the controller, a height adjustment parameter for a suspension system of the vehicle based on the roughness determined.

An emergency egress system for a multi-passenger vehicle such as a school bus (10) includes a housing (30) that operatively supports a ramp (34) in movable connection therewith. Opening an emergency exit door (18) of the bus causes a housing door (24) to open and the ramp to move outwardly from a retracted position toward an extended position. Opening the emergency exit door also causes the suspension of the bus to be automatically lowered to place the emergency exit opening (16) closer to the ground (166).

A vehicle height control system and method of increasing a vehicle height of a vehicle having a vehicle body and at least one axle assembly. The vehicle height control system includes a pressurized fluid supply system configured to supply a pressurized fluid, and a plurality of air springs provided to elastically support at least one section of the vehicle body of the vehicle above at least one axle assembly of the vehicle and configured to adjust the vehicle height of such sections of the vehicle body relative to a ground surface in response to the supply and discharge of the pressurized fluid. A control assembly of the vehicle height control system has a piston unit fluidically interconnected with the pressurized fluid supply system via a first control valve and is operable to adjust the vehicle height by adjusting a second control valve interposed between the pressurized fluid supply system and the air springs. A controller is configured to receive user input indicative of a Vehicle height adjustment operation desired by a user and to adjust the vehicle height by controlling the control assembly based on the user input.

A method and system for operating pneumatic suspension system including a plurality of air springs changing a ride height of the motor vehicle by the supply and extraction of compressed air, at least two first axle air springs, and two second axle air springs, an air spring valve, a first and further changeover valve are arranged in a compressed air path, an additional accumulator valve, the second compressed air path is connected to the first compressed air path via a third compressed air path in which a connecting valve is provided, for simultaneous adjustment of the ride height of the vehicle on both axles, the air spring valves, and the first and the further changeover valves and the additional accumulator valve are opened at the same time while the connecting valve remains closed.

A method and system for adjusting height and damping force, the method comprising: between a first connection part (110) and a second connection part (120), arranging a pneumatic valve (130), an air spring (140), an adjustable damper (150) and a damping force adjustment device (160) used for adjusting the damping force of an adjustable damper (150), the positions of the pneumatic valve (130), the air spring (140), the adjustable damper (150) and the damping force adjustment device (160) being adaptive and the pneumatic valve (130) being connected to the damping force adjustment device (160) and the air spring (140), respectively; the pneumatic valve (130) collects at least one movement variable of the first connection part (110) relative to the second connection part (120); meanwhile, the pneumatic valve (130), according to the collected movement variable and/or the change in the movement variable, controlling the air spring (140) to inflate or deflate so as to implement height adjustment; and/or carrying out gas driving on the damping force adjustment device (160) to control the adjustable damper (150) to output corresponding damping force, so as to adjust the size of the damping force of the adjustable damper (150), which improves the sensitivity of height adjustment and damping force adjustment.

An air spring suspension system includes a first air spring that has a first volume with a first pressure that is configured to provide a first spring stiffness to a first suspension assembly. A second air spring has a housing with a second volume with a second pressure that is configured to provide a second spring stiffness to a second suspension assembly. The second air spring includes a piston that is arranged in the second volume. One of the housing and the piston includes a first mounting structure that is configured to connect to a vehicle chassis. Another of the housing and the piston includes a second mounting structure that is configured to connect to the second suspension assembly. The second air spring also includes a fluid connection on the housing. The second air spring further includes a crosslink valve that is disposed in the housing and movable between open and closed positions. The crosslink valve is configured to selectively fluidly connect the second volume to the fluid connection. A crosslink line is fluidly connected to the first volume of the first air spring and the fluid connection on the second air spring. A controller is in communication with the crosslink valve. The controller is configured to command the crosslink valve between the open and closed positions in response to an input.

An air suspension system includes an air supply system block including one or more air spring valves, where the one or more air spring valves are disposed within the air supply system block, the air supply system block having a valve block housing. The system further includes the air supply system block pneumatically coupled with one or more air springs, and at least one reservoir coupled with the air supply system block, at least one motor and pump disposed within the air supply system block. The air suspension further includes fast down leveling valves disposed within the air supply system block.