Methods and apparatus to determine vehicle weight are disclosed. An example apparatus includes a vehicle controller configured to control a motor operatively coupled to a suspension system to raise or lower a vehicle. The vehicle controller is to also determine a first parameter of the motor while controlling the motor to raise or lower the vehicle when the vehicle is unloaded. The vehicle controller is to also determine a second parameter of the motor while controlling the motor to raise or lower the vehicle when the vehicle is at least partially loaded. The vehicle controller is to also calculate a weight of the vehicle based on the first and second parameters of the motor.

A device for supplying hydraulic energy in a chassis system of a vehicle includes a first hydraulic pump and a first electric motor for driving the first hydraulic pump, a second hydraulic pump and a second electric motor for driving the second hydraulic pump, and a common electronic unit which is arranged to control the first and the second electric motor, wherein the two electric motors and the two pumps are preferably designed to be identical in structure and/or respectively form first and second motor-pump groups.

Method to control active shock absorbers of a road vehicle. Each active shock absorber is part of a suspension connecting a frame to a hub of a wheel and is provided with an actuator. The control method comprises the steps of: determining a longitudinal acceleration and a transverse acceleration of the road vehicle; establishing a desired lowering of a centre of gravity of the road vehicle depending on the longitudinal acceleration and on the transverse acceleration; and controlling the actuator of each active shock absorber so as to obtain the desired lowering of the centre of gravity.

Method to control active shock absorbers of a road vehicle. Each active shock absorber is part of a suspension connecting a frame to a hub of a wheel and is provided with an actuator. The control method comprises the steps of: determining a longitudinal acceleration and a transverse acceleration of the road vehicle; establishing a desired roll angle based on the transverse acceleration; and establishing a desired pitch angle based on the longitudinal acceleration.

A vehicle suspension system comprising a hydropneumatic strut comprising a fluid interface, where supply of hydraulic fluid to the strut via the fluid interface causes the overall length of the strut to increase, and withdrawal of hydraulic fluid via the fluid interface causes the overall length of the strut to decrease, a first displacement system in fluid communication with the fluid interface, capable of supplying and withdrawing fluid to and from the strut as well as measuring the volume of fluid supplied or withdrawn from the strut, a second displacement system in fluid communication with the fluid interface, and a hydraulic fluid source for selectively supplying or withdrawing hydraulic fluid from the hydropneumatic strut via either of the first or second displacement systems.

A hydraulic suspension system for a motor vehicle having at least a pair of road engaging wheels. The suspension system includes, a hydraulic cylinder coupled with the each of the pair of road engaging wheels, the hydraulic cylinder defining a cap end volume and a rod end volume separated by a piston. A hydraulic supply circuit for the hydraulic cylinder includes, a high pressure hydraulic source, a low pressure hydraulic drain, a pair of hydraulic sub circuits each coupled to one of the hydraulic cylinder cap and rod end volumes. Each hydraulic sub circuit includes, a proportional supply flow valve coupled with the high pressure hydraulic source and one of the cylinder volumes, a return flow control proportional valve coupled with the low pressure hydraulic drain and the one cylinder volume, and an accumulator coupled to the associated hydraulic cylinder volume through an accumulator fill control proportional valve.

A system includes: a state module configured to selectively set a present state to a first state; a valve control module configured to determine first target open and closed states for valves of a suspension system based on the present state and to open and close the valves according to the first target open and closed states, respectively; a pump control module configured to, when the valves are in the first target open and closed states, respectively, selectively operate an electric pump in a first direction to increase hydraulic fluid pressure in a first portion of the suspension system; and a leak module configured to selectively diagnose a leak in a first one of the valves associated with the first state based on a first pressure in the first portion of the suspension system while the valves are open and closed according to the first target open and closed states.

An energy-dissipative pneumatic cushioning system for cushioning heavy loads includes (i) one or more support members that extend beneath at least a portion of at least one pneumatic cushioning element and (ii) at least one connector assembly that communicatively couple the at least one pneumatic cushioning element to a gas supply unit and optionally at least one gas reservoir. The at least one gas reservoir is capable of accepting at least a portion of gas from the at least one pneumatic cushioning element under a force of a load. The at least one connector assembly is further operable to allow a return of at least a portion of the gas to the at least one pneumatic cushioning element upon reduction of at least a portion of the force of the load.

An active-passive dual mode switchable vehicle suspension system is provided. The suspension system includes a filter, a hydraulic pump, a one-way valve, a power takeoff, a servo valve, a suspension cylinder, an overflow valve, an energy accumulator, a reversing valve, a first pressure sensor, a second pressure sensor, a controller, an oil tank and a displacement sensor. Further related is a switching method for the active-passive dual mode switchable vehicle suspension system. When the active and passive dual-mode switchable vehicle suspension system is switched between modes, an oil pressure in the rodless cavity of the suspension cylinder and an oil pressure in the energy accumulator are adjusted to be equal in advance, so that the stable switching of the active-passive suspension system can be realized, and the vibration of the vehicle body is eliminated when the existing active-passive suspension system is switched. Moreover, the accumulator and overflow valve can be shared in the active and passive suspension mode, thereby effectively reducing the use number of accumulators and overflow valves, greatly saving the layout space of the vehicle body, effectively reducing the total weight of the vehicle body, which is favorable to the lightweight of the vehicle chassis.

A hydraulic actuator for a vehicle suspension includes: a pump assembly including an electric motor coupled to first and second pumps to transfer hydraulic fluid to a discharge header; a first isolation valve having an elastomeric seat and configured to selectively block fluid flow from a port in fluid communication with a height-adjustable damper to the discharge header; and a second isolation valve having a metal seat and connected in series with the first isolation valve to selectively block fluid flow from the port to the discharge header. The first pump transfers hydraulic fluid from a supply fluid passage to a first discharge header, and the second pump transfers hydraulic fluid from the supply fluid passage to a second discharge header. A recirculation valve selectively controls fluid flow from the second discharge header to the supply fluid passage.