Disclosed herein are active hydraulic cylinders for use in active vehicle suspension systems, and methods for assembling active hydraulic cylinders for use in an active vehicle suspension system. In particular, in certain embodiments a manifold may encircle a portion of an outer tube of a twin tube assembly. The manifold may mechanically and fluidly couple a pump assembly to the twin tube assembly. In certain embodiments, the manifold may be welded onto the outer tube.

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 vehicle height adjustment device includes a spring having one end supported on a vehicle body side and another end supported on a wheel side. An adjustor includes an accommodation chamber accommodating fluid and adjusts a length of the spring in accordance with an amount of fluid in the accommodation chamber. A storage chamber stores fluid. A guide passage guides fluid from the accommodation chamber to the storage chamber. An actuator includes an operation rod to press a push rod. A valve body closes the guide passage when seated on a seat and opens the guide passage when pressed and detached from the seat by the push rod. A press member includes a contact portion and a shaft. The press member presses and seats the valve body on the seat. An accommodation member accommodates the valve body and the contact portion. A support member supports the shaft movably.

A suspension device includes an actuator device provided with an extensible/contractible actuator body interposed between a sprung member and an unsprung member of a vehicle, a pump that supplies fluid to the actuator body to extend or contract the actuator body, and a controller that controls a rotation number of the pump. The controller has a road surface state index obtainment unit that obtains a road surface state index and a target rotation number determination unit that determines a target rotation number of the pump on the basis of the road surface state index.

The suspension comprises a mechanical spring interposed between an unsprung mass (UM) and a sprung mass (SM) of the vehicle, a shock-absorber interposed between the unsprung mass (UM) and the sprung mass (SM), in parallel with the mechanical spring, a hydraulic linear actuator, an accumulator, a tank (T) containing an incompressible working fluid and a hydraulic circuit for hydraulically connecting, the hydraulic linear actuator, the accumulator and the tank (T) with each other. A single reversible pump (P) is arranged along the third hydraulic line. A reversible electric motor (M) drives the pump (P) in either direction, and a plurality of valves (V.sub.1, V.sub.2, V.sub.3, V.sub.4, V.sub.5, V.sub.S) control the flow of the working fluid between the accumulator, the tank (T) and the hydraulic linear actuator.

A damping control system includes: a damping chamber connected to one of (a) a body of a vehicle and (b) a wheel of the vehicle; a piston that is slidably disposed within the damping chamber and that includes: a piston rod that is connected to the other one of (a) the body of the vehicle and (b) the wheel of the vehicle; and a plunger that is connected to the piston rod and that divides the damping chamber into a first chamber and a second chamber; a first valve that regulates hydraulic fluid flow out of the first chamber; and a valve control module configured to selectively close the first valve when a position of the plunger is between (a) a first reference position within the first chamber and (b) a first end stop of the damping chamber that defines a boundary of the first chamber.

A suspension system and associated control methods for improving comfort by disabling passive pitch stiffness in the suspension system by holding open electromechanical comfort valves positioned in a manifold assembly of the suspension system. The manifold comfort valves are held open to disable the passive pitch stiffness of the suspension system if the vehicle is traveling down a rough road or if the vehicle is approaching a discrete road event like a pot-hole or speed bump. Deactivation of the passive pitch stiffness of the suspension system is determined based on road classification information, saved road events, and/or real-time vehicle data from on-board sensors. The suspension system therefore reduces pitch angles during pitch events induced by inertial forces caused by driver inputs and disables the pitch stiffness when the pitch event is caused by road inputs.

A vehicle height adjustment device includes a changer and a controller. The changer is configured to change a relative position of a body of a vehicle relative to an axle of a wheel of the vehicle. The controller is configured to control the changer to make the relative position a target value so as to control a vehicle height of the body of the vehicle. The controller is configured to control the changer to maintain the relative position irrespective of the target value when a decreasing malfunction occurs causing the vehicle height to decrease.

A damping control system includes: a damping chamber connected to one of (a) a body of a vehicle and (b) a wheel of the vehicle; a piston that is slidably disposed within the damping chamber and that includes: a piston rod that is connected to the other one of (a) the body of the vehicle and (b) the wheel of the vehicle; and a plunger that is connected to the piston rod and that divides the damping chamber into a first chamber and a second chamber; a first valve that regulates hydraulic fluid flow out of the first chamber; and a valve control module configured to selectively close the first valve when a position of the plunger is between (a) a first reference position within the first chamber and (b) a first end stop of the damping chamber that defines a boundary of the first chamber.

A suspension device includes: a damper that has an extension-side chamber and a contraction-side chamber; an extension-side passage connected to the extension-side chamber; a contraction-side passage connected to the contraction-side chamber; a switching device that connects one of the extension-side passage and the contraction-side passage to the supply passage and connecting the other of the extension-side passage and the contraction-side passage to the discharge passage selectively; an extension-side damping element provided in the extension-side passage; a contraction-side damping element provided in the contraction-side passage; a control valve capable of adjusting a pressure in the supply passage; an intake check valve provided midway in the intake passage; and a supply-side check valve provided in the supply passage between the control valve and the pump.