A suspension system including four dampers is disclosed where each damper includes a compression chamber and a rebound chamber. A first hydraulic circuit includes a front hydraulic line, a rear hydraulic line, and a first longitudinal hydraulic line that extends between and fluidly connects the front and rear hydraulic lines of the first hydraulic circuit. A second hydraulic circuit includes a front hydraulic line, a rear hydraulic line, and a second longitudinal hydraulic line that extends between and fluidly connects the front and rear hydraulic lines of the second hydraulic circuit. First and second longitudinal comfort valves are positioned in the first and second longitudinal hydraulic lines, respectively, between the front and rear hydraulic lines. Both of the first and second longitudinal comfort valves are electromechanical valves and can be actuated to couple and decouple front axle roll control from rear axle roll control.

A vehicle includes a suspension system having a first damper, a second damper, and a controller. The dampers include housings and pistons sealingly interfaced with an inner diameter of the housing, dividing the damper into a first and second chamber. The suspension system includes proportional variable relief valves which control pressure of fluid entering or exiting one of the first and second chamber of one of the first and second damper. The controller controls the valves to control extension or compression of the first damper and extension or compression of the second damper based on a degree of roll of the vehicle during a turn of the vehicle or a degree of pitch of the vehicle during acceleration or deceleration of the vehicle. The first and second damper control a roll and pitch of the vehicle. The valves control a damping rate of one of the first and second damper.

A vehicle includes a suspension system having a first damper, a second damper, valves and a controller. Each of the first damper and the second damper include a housing and a piston sealingly interfaced with an inner diameter of the housing, dividing the damper into a first and second chamber. Each valve controls flow rate of fluid entering or exiting at least one of the first and second chamber of at least one of the first damper and the second damper. The controller controls the valves to control extension or compression of at least one of the first damper and the second damper based on at least one of a degree of roll of the vehicle during a turn of the vehicle and a degree of pitch of the vehicle during acceleration of the vehicle or a degree of pitch of the vehicle during deceleration of the vehicle.

A control system includes: a target volume module configured to determine a target volume of hydraulic fluid within a suspension system of a vehicle based on a target pressure of the hydraulic fluid within the suspension system; a volume command module configured to generate a volume command based on the target volume and a present volume of the hydraulic fluid within first and second circuits; a command module configured to, based on the volume command, generate: a pump command for an electric hydraulic fluid pump; and first and second valve commands for first and second seat valves that regulate hydraulic fluid flow to and from the first and second circuits, respectively; a valve control module that actuates the first and second seat valves based on the first and second valve commands, respectively; and a pump control module that controls operation of the pump based on the pump command.

A suspension system including four dampers is disclosed where each damper includes a compression chamber and a rebound chamber. A first hydraulic circuit includes a front hydraulic line, a rear hydraulic line, and a first longitudinal hydraulic line that extends between and fluidly connects the front and rear hydraulic lines of the first hydraulic circuit. A second hydraulic circuit includes a front hydraulic line, a rear hydraulic line, and a second longitudinal hydraulic line that extends between and fluidly connects the front and rear hydraulic lines of the second hydraulic circuit. First and second longitudinal comfort valves are positioned in the first and second longitudinal hydraulic lines, respectively, between the front and rear hydraulic lines. Both of the first and second longitudinal comfort valves are electromechanical valves and can be actuated to couple and decouple front axle roll control from rear axle roll control.

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 suspension system and associated control methods that reduce temperature related fluctuations in the internal pressures and stiffness of the suspension system. A manifold assembly is connected in fluid communication with a plurality of dampers via hydraulic circuits and a pump assembly via a pump hydraulic line. Onboard sensors generate real-time data regarding the vehicle. A suspension control unit, arranged in electronic communication with the aforementioned components, monitors the real-time data, sets a target stiffness and a target pressure, calculates an effective stiffness based on the real-time data, determines if the effective stiffness is above or below the target stiffness and sets a new target pressure accordingly by making stepwise decreases or increases until the new target pressure is reached.

A system for grading filling of a suspension system includes: a pump control module configured to, during first and second periods, operate an electric pump of the suspension system in first and second directions and decreasing and increasing hydraulic fluid pressure within the suspension system, respectively; a monitoring module configured to: store a first pressure of hydraulic fluid within the suspension system measured using a pressure sensor when the first pressure is less than or equal a first predetermined pressure while the pump is operated in the first direction; and store a second pressure measured using the pressure sensor when the second pressure is greater than or equal a second predetermined pressure while the pump is operated in the second direction; and a grade module configured to determine a grade value for the filling of the suspension system based on the first and second pressures.

A rinsing system includes: a pump control module configured to, when a hydraulic line is connected to a port that is fluidly connected to a hydraulic line of a suspension system, selectively operate a hydraulic fluid pump of the suspension system and pump hydraulic fluid from a hydraulic fluid tank of the suspension system through the hydraulic fluid pump toward the hydraulic line; and a valve control module configured to, when the hydraulic line is connected to the port and the hydraulic fluid pump is pumping hydraulic fluid, open valves of the suspension system and fluidly connect the hydraulic fluid pump with the hydraulic line.

A suspension system and associated control methods for improving the effectiveness of driver assistance systems is disclosed where the driver assistance systems can generate and send requests to a suspension control unit (SCU) of the suspension system to actuate (e.g., close) one or more comfort valves in the suspension system to increase the roll stiffness and/or pitch stiffness of the suspension system when the driver assistance systems are taking corrective action. As part of a two-way communication between the suspension control unit (SCU) and the driver assistance systems, the suspension control unit (SCU) communicates target stiffnesses and/or calculated effective stiffnesses to the driver assistance systems, which is used to update the vehicle stability models used by the driver assistance systems.