阅读说明：本技术 具有多种工作模式的悬架系统 (Suspension system with multiple operating modes ) 是由 M·阿尔·萨克卡 M·丹斯 于 2020-04-15 设计创作，主要内容包括：本发明公开了一种主动悬架系统,该主动悬架系统包括右阻尼器和左阻尼器、泵和控制阀系统。该右阻尼器和该左阻尼器中的每者包括阻尼器壳体、活塞杆和安装在该活塞杆上的活塞。该活塞被布置成在该阻尼器壳体内部滑动接合,使得该活塞将该阻尼器壳体分成第一工作室和第二工作室。该泵包括泵入口和泵出口。该控制阀系统与该右阻尼器的该第一工作室和该第二工作室、该左阻尼器的该第一工作室和该第二工作室、该泵入口以及该泵出口进行流体连通地连接。该控制阀系统具有为该主动悬架系统提供不同工作模式的流体流动路径的若干不同布置。(The invention discloses an active suspension system, which comprises a right damper, a left damper, a pump and a control valve system. Each of the right damper and the left damper includes a damper housing, a piston rod, and a piston mounted on the piston rod. The piston is arranged for sliding engagement within the damper housing such that the piston divides the damper housing into a first working chamber and a second working chamber. The pump includes a pump inlet and a pump outlet. The control valve system is connected in fluid communication with the first and second working chambers of the right damper, the first and second working chambers of the left damper, the pump inlet, and the pump outlet. The control valve system has several different arrangements of fluid flow paths that provide different operating modes for the active suspension system.)

1. An active suspension system, comprising:

a right damper and a left damper each comprising a damper housing, a piston rod, and a piston mounted on the piston rod and arranged for sliding engagement inside the damper housing such that the piston divides the damper housing into a first working chamber and a second working chamber;

a pump comprising a pump inlet and a pump outlet;

a hydraulic reservoir; and

a control valve system connected in fluid communication with the first and second working chambers of the right damper, the first and second working chambers of the left damper, the pump inlet, the pump outlet, and the hydraulic reservoir,

the control valve system has:

a first arrangement of fluid flow paths wherein the pump inlet is prevented from fluid communication with the hydraulic reservoir while the pump inlet is in fluid communication with the first working chamber of the left damper and the second working chamber of the right damper, the pump outlet is in fluid communication with the first working chamber of the right damper and the second working chamber of the left damper; and

a second arrangement of fluid flow paths, wherein the pump inlet is prevented from fluid communication with the hydraulic reservoir while in fluid communication with the first working chamber of the right damper and the second working chamber of the left damper, the pump outlet is in fluid communication with the first working chamber of the left damper and the second working chamber of the right damper, wherein for the first and second arrangements of fluid flow paths, the first working chamber of the right damper and the second working chamber of the left damper are fluidly isolated from the second working chamber of the right damper and the first working chamber of the left damper.

2. The active suspension system of claim 1 further comprising a third arrangement of fluid flow paths wherein said pump outlet is connected in fluid communication with said first working chamber of said right and left dampers and said second working chamber of said right and left dampers, said pump inlet being in fluid communication with said hydraulic reservoir.

3. The active suspension system of claim 2 further comprising an accumulator in communication with and fluidly isolated from the first working chambers of the right and left dampers.

4. The active suspension system of claim 1 wherein the pump is operable in a lockout mode in which fluid flow through the pump is restricted and a free-running mode in which fluid can pass through the pump regardless of whether the pump is energized.

5. An active suspension system, comprising:

a right damper and a left damper each comprising a damper housing, a piston rod, and a piston mounted on the piston rod and arranged for sliding engagement inside the damper housing such that the piston divides the damper housing into a first working chamber and a second working chamber;

a pump comprising a pump inlet and a pump outlet; and

a control valve system connected in fluid communication with the first and second working chambers of the right damper, the first and second working chambers of the left damper, the pump inlet, and the pump outlet;

the control valve system has:

a first arrangement of fluid flow paths wherein the pump outlet is connected in fluid communication with the first working chamber of the right damper and the first working chamber of the left damper and the second working chamber of the right damper and the second working chamber of the left damper;

a second arrangement of fluid flow paths wherein the pump outlet is fluidly isolated from the second working chambers of the right and left dampers and from the first working chambers of the right and left dampers;

a third arrangement of fluid flow paths wherein said pump outlet is connected in fluid communication with and fluidly isolated from said first working chamber of said left damper and said second working chamber of said right damper; and

a fourth arrangement of fluid flow paths, wherein the pump outlet is connected in fluid communication with and fluidly isolated from the first working chambers of the right and left dampers.

6. The active suspension system of claim 5 further comprising:

a hydraulic reservoir connected in fluid communication with the control valve system.

7. The active suspension system of claim 6 wherein the pump inlet is connected in fluid communication with the hydraulic reservoir in the first arrangement of fluid flow paths.

8. The active suspension system of claim 5 wherein the pump inlet is connected in fluid communication with the first working chamber of the right damper and the second working chamber of the left damper in the third arrangement of fluid flow paths.

9. The active suspension system of claim 5 wherein the pump inlet is connected in fluid communication with the second working chamber of the right damper and the first working chamber of the left damper in the fourth arrangement of fluid flow paths.

10. The active suspension system of claim 5 wherein in the second arrangement of fluid flow paths, the first and second working chambers of the right damper are connected in fluid communication with each other and the first and second working chambers of the left damper are connected in fluid communication with each other.

11. The active suspension system of claim 6 wherein the pump inlet is prevented from fluid communication with the hydraulic reservoir in the second arrangement of fluid flow paths.

12. The active suspension system of claim 5 wherein the control valve system comprises a single valve body having five different operating positions defining each of the first, second, third and fourth arrangements of fluid flow paths.

13. The active suspension system of claim 5 wherein the control valve system comprises first, second and third separate valve bodies defining the first, second, third and fourth arrangements of fluid flow paths.

14. The active suspension system of claim 5 further comprising a make-up circuit in fluid communication with the control valve system, the make-up circuit including an accumulator in one-way fluid communication with one of the second working chambers and a restricted outlet in fluid communication with the one of the first working chambers.

15. The active suspension system of claim 5 wherein the pump is operable in a lockout mode in which fluid flow through the pump is restricted and a free-running mode in which fluid can pass through the pump regardless of whether the pump is energized.

16. An active suspension system, comprising:

a right damper and a left damper each comprising a damper housing, a piston rod, and a piston mounted on the piston rod and arranged for sliding engagement inside the damper housing such that the piston divides the damper housing into a first working chamber and a second working chamber;

a pump comprising a pump inlet and a pump outlet;

a hydraulic reservoir; and

a control valve system connected in fluid communication with the first and second working chambers of the right damper, the first and second working chambers of the left damper, the pump inlet, the pump outlet, and the hydraulic reservoir,

wherein the control valve system switches the active suspension system between an active roll control mode, a passive roll control mode, a pressure control mode, and a comfort mode, the active roll control mode including energizing the pump to provide pressurized fluid to the first working chamber of the right damper and the second working chamber of the left damper, the passive roll control mode including fluidly interconnecting the first working chamber of the right damper and the second working chamber of the left damper without energizing the pump.

17. An active suspension system, comprising:

a right damper and a left damper each including a damper housing divided into a first working chamber and a second working chamber;

a source of pressurized fluid;

means for operating the active suspension system in an active roll control mode and at least one of a passive roll control mode, a pressure control mode, and a comfort mode, wherein the active control mode includes transferring energy from the source of pressurized fluid to one of the first and second working chambers, and the passive roll control mode includes transferring energy from an external load applied to one of the right and left dampers to the other of the right and left dampers when the source of pressurized fluid is disconnected from the right and left dampers.

18. The active suspension system of claim 17, wherein the means for operating the active suspension system allows operation in only two of the active roll control mode, the passive roll control mode, the pressure control mode, and the comfort mode.

19. The active suspension system of claim 17, wherein the means for operating the active suspension system comprises means for operating an active suspension in each of the active roll control mode, the passive roll control mode, the pressure control mode, and the comfort mode.

20. A vehicle suspension system for a vehicle including a body that experiences a roll moment caused by movement of the vehicle, the vehicle suspension system comprising:

a right damper and a left damper each including a damper housing divided into a first working chamber and a second working chamber;

a hydraulic system in fluid communication with the working chamber of the damper to hydraulically vary the response of the vehicle body to the roll moment, the hydraulic system selectively configurable to provide:

(a) an active roll control mode in which the roll moment on the vehicle body is cancelled by inputting hydraulic energy into the hydraulic system, and

(b) and at least one of:

(1) a passive roll control mode in which the roll moment on the vehicle body is cancelled without inputting hydraulic energy into the hydraulic system,

(2) a pressure control mode in which a resistance level of the vehicle body to the roll moment is defined by setting a hydraulic pressure in the hydraulic system, and

(3) a comfort mode in which the roll moment on the vehicle body is not substantially changed.

21. The active suspension system of claim 16, 17 or 20 wherein the passive roll control mode provides a target roll stiffness based on: the first working chamber of the left damper and the second working chamber of the right damper are in fluid communication with each other in a first circuit and fluidly isolate the first circuit from a second circuit that includes the second working chamber of the left damper in fluid communication with the first working chamber of the right damper.

22. The active suspension system of claim 16, 17 or 20 wherein the active roll control mode includes fluidly interconnecting one of a pump inlet and a pump outlet with the first working chamber of the left damper and the second working chamber of the right damper and interconnecting the other of the pump inlet and the pump outlet with the second working chamber of the left damper and the first working chamber of the right damper.

23. The active suspension system of claim 16, 17 or 20 wherein said pressure control mode includes means for fluidly interconnecting one of a pump inlet and a pump outlet with a hydraulic reservoir and the other of said pump inlet and said pump outlet with said first and second working chambers of said left damper and said first and second working chambers of said right damper.

24. The active suspension system of claim 16, 17 or 20 wherein said comfort mode includes means for fluidly interconnecting said first and second working chambers of said left damper with said first and second working chambers of said right damper.

25. The active suspension system of claim 16, 17 or 20 wherein the right and left dampers are operable to adjust a ride height of a vehicle equipped with the active suspension system when in the pressure control mode.

Technical Field

The present disclosure relates generally to suspension systems for motor vehicles and more particularly to active suspension systems that replace or augment mechanical/anti-roll bars.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Suspension systems improve the ride of the vehicle by absorbing jolts and vibrations that would otherwise destabilize the vehicle body. Suspension systems also improve safety and control by improving contact between the ground and the vehicle tires. One disadvantage of suspension systems is that the basic spring/damper arrangement will allow the vehicle to roll/lean during cornering (i.e., turning). The lateral acceleration when the vehicle undergoes a turn results in a roll moment, wherein the vehicle will lean/lean to the right when turning to the left and to the left when turning to the right. The roll moment reduces the grip and cornering performance and may also be uncomfortable for the driver and passengers. Many vehicles are equipped with stabilizer/anti-roll bars, which are mechanical systems that help counteract the roll moment experienced during cornering. The stabilizer/anti-roll bar is typically a mechanical link extending laterally across the width of the vehicle between the right and left dampers. When one of the dampers extends, the stabilizer/anti-roll bar applies a force to the opposing damper that counteracts the roll moment of the vehicle and helps correct the roll angle to provide a flatter turn. However, there are several disadvantages associated with these mechanical systems. First, there are often packaging constraints associated with mechanical systems, as the stabilizer/anti-roll bar requires a relatively straight, unobstructed path across the vehicle between the right and left dampers. Second, the stabilizer/anti-roll bar is reactive and therefore only functions when the suspension begins to move (i.e., tilt). Such mechanical systems do not limit body roll at the moment of starting the turn. Accordingly, there remains a need for an improved vehicle suspension system that can augment or replace conventional mechanical stabilizer/anti-roll bars.

Disclosure of Invention

This section provides a general summary of the disclosure, and is not a complete disclosure of the full scope of the invention or all of its features.

In accordance with one aspect of the subject disclosure, an active suspension system is provided. The active suspension system includes right and left dampers, a pump, and a control valve assembly. Each of the right damper and the left damper includes a damper housing, a piston rod, and a piston mounted on the piston rod. The piston is arranged for sliding engagement within the damper housing such that the piston divides the damper housing into a first working chamber and a second working chamber. The pump includes a pump inlet and a pump outlet. The control valve assembly is connected in fluid communication with the first and second working chambers of the right damper, the first and second working chambers of the left damper, the pump inlet, and the pump outlet. The control valve assembly has several different arrangements of fluid flow paths that provide different operating modes for the active suspension system.

The control valve assembly includes a first arrangement of fluid flow paths in which the pump outlet is connected in fluid communication with the first working chamber of the right damper and the first working chamber of the left damper. In the first arrangement of the fluid flow path through the control valve assembly, the pump outlet is fluidly isolated from the second working chamber of the right damper and the second working chamber of the left damper. In accordance with the first arrangement of fluid flow paths through the control valve assembly, the pump operates to increase fluid pressure in only the first working chamber of the right damper and the first working chamber of the left damper.

The control valve assembly includes a second arrangement of fluid flow paths in which the pump outlet is connected in fluid communication with the second working chamber of the right damper and the second working chamber of the left damper. In the second arrangement of the fluid flow path through the control valve assembly, the pump outlet is fluidly isolated from the first working chamber of the right damper and the first working chamber of the left damper. In accordance with the second arrangement of fluid flow paths through the control valve assembly, the pump operates to increase fluid pressure in only the second working chamber of the right damper and the second working chamber of the left damper.

The control valve assembly includes a third arrangement of fluid flow paths in which the pump outlet is connected in fluid communication with the first working chamber of the left damper and the second working chamber of the right damper. In the third arrangement of the fluid flow path through the control valve assembly, the pump outlet is fluidly isolated from the first working chamber of the right damper and the second working chamber of the left damper. In accordance with the third arrangement of fluid flow paths through the control valve assembly, the pump operates to increase fluid pressure in only the first working chamber of the left damper and the second working chamber of the right damper.

The control valve assembly includes a fourth arrangement of fluid flow paths in which the pump outlet is connected in fluid communication with the first working chamber of the right damper and the second working chamber of the left damper. In the fourth arrangement of the fluid flow path through the control valve assembly, the pump outlet is fluidly isolated from the second working chamber of the right damper and the first working chamber of the left damper. In accordance with the fourth arrangement of fluid flow paths through the control valve assembly, the pump operates to increase fluid pressure in only the first working chamber of the right damper and the second working chamber of the left damper.

According to another aspect of the present disclosure, the active suspension system includes a plurality of hydraulic lines connecting the pump and the right and left dampers to the control valve assembly. The plurality of hydraulic lines includes a first hydraulic line extending between and fluidly connecting the first working chamber of the right damper and the control valve assembly. The plurality of hydraulic lines includes a second hydraulic line extending between and fluidly connecting the second working chamber of the right damper and the control valve assembly. The plurality of hydraulic lines includes a third hydraulic line extending between and fluidly connecting the first working chamber of the left damper and the control valve assembly. The plurality of hydraulic lines includes a fourth hydraulic line extending between and fluidly connecting the second working chamber of the left damper and the control valve assembly. The plurality of hydraulic lines includes a fifth hydraulic line and a sixth hydraulic line extending between and fluidly connecting the pump and the control valve assembly. The pump may be a bi-directional pump in which the pump inlet and the pump outlet are switched according to the direction in which the pump is operated. Thus, either one of the fifth hydraulic line and the sixth hydraulic line may operate as a pump suction line, and either one of the fifth hydraulic line and the sixth hydraulic line may operate as a pump discharge line.

The control valve assembly provides a first mode of operation in which the pump discharge line is connected in fluid communication with the first hydraulic line and the third hydraulic line. In the first operating mode, the pump increases fluid pressure in the first working chamber of the right damper and the first working chamber of the left damper. The pump discharge line is fluidly isolated from the second and fourth hydraulic lines in the first operating mode such that the pump does not increase fluid pressure in the second working chamber of the right damper and the second working chamber of the left damper. The control valve assembly also provides a second mode of operation in which the pump discharge line is connected in fluid communication with the second hydraulic line and the fourth hydraulic line. In the second operating mode, the pump increases fluid pressure in the second working chamber of the right damper and the second working chamber of the left damper. The pump discharge line is fluidly isolated from the first and third hydraulic lines in the second mode of operation such that the pump does not increase fluid pressure in the first working chambers of the right and left dampers. The control valve assembly also provides a third mode of operation in which the pump discharge line is connected in fluid communication with the second hydraulic line and the third hydraulic line. In the third mode of operation, the pump increases fluid pressure in the second working chamber of the right damper and the first working chamber of the left damper. The pump discharge line is fluidly isolated from the first and fourth hydraulic lines in the third operating mode such that the pump does not increase fluid pressure in the first working chamber of the right damper and the second working chamber of the left damper. The control valve assembly also provides a fourth mode of operation in which the pump discharge line is connected in fluid communication with the first hydraulic line and the fourth hydraulic line. In the fourth mode of operation, the pump increases fluid pressure in the first working chamber of the right damper and the second working chamber of the left damper in the fourth mode of operation. The pump discharge line is fluidly isolated from the second and third hydraulic lines in the fourth operating mode such that the pump does not increase fluid pressure in the second working chamber of the right damper and the first working chamber of the left damper.

According to another aspect of the present disclosure, the active suspension system further includes a hydraulic reservoir fluidly connected to the control valve assembly by a seventh hydraulic line. The control valve assembly includes a valve block having a plurality of valve block segments that provide different combinations of fluid flow paths through the control valve assembly (such as those described above). The different fluid flow paths through the control valve assembly provide different operating modes of the active suspension system. Each valve block section includes connections for each of the first, second, third, fourth, fifth, sixth and seventh hydraulic lines.

Advantageously, the control valve assembly provides an active suspension system having a variety of different capabilities not previously available in a single system using a single pump. The active suspension system is capable of reducing/eliminating vehicle roll angle while cornering, and can achieve negative roll angle even in the case where the vehicle is banked to improve handling. The reduction in roll angle improves the comfort, steering feel, agility, and stability of the vehicle. Roll control is provided by roll stiffness (based on static pressure in the system) and anti-roll active torque (generated by the pump). This translates into a reduced overall vehicle roll stiffness compared to a vehicle with a conventional anti-roll bar. Thus, comfort is improved. Comfort is also improved because the main force is independent of the damping force. Since part of the roll control is provided by the static pressure in the system, the overall power consumption of the system is reduced and failsafe is provided, since the system may rely on passive roll stiffness in case of failure of the active component (pump/motor/inverter). Further handling improvements may be achieved by adjusting the active roll torque between the front axle/rear axle depending on driving conditions (e.g., limiting understeer behavior during curve acceleration). Anti-roll torque may also be applied to reduce body oscillations, thereby improving comfort.

The control valve assembly may connect the pump outlet to the first working chamber of the right damper and the first working chamber of the left damper or the second working chamber of the right damper and the second working chamber of the left damper to increase the fluid pressure in those respective chambers of the dampers. The control valve assembly may also connect the pump outlet to the first working chamber of the right damper and the first working chamber of the left damper or the second working chamber of the right damper and the second working chamber of the left damper to reduce the fluid pressure in those respective chambers. Thus, the pump of the active stabilizer bar system can be used to vary the static pressure in the working chamber of the damper and thus the passive roll stiffness of the system. The control valve assembly may be used to reduce (i.e. lower) the ride height of the vehicle by connecting the pump outlet to the first working chambers of the right and left dampers and connecting the pump inlet to the second working chambers of the right and left dampers. The control valve assembly may also be used to increase (i.e., lift/raise) the ride height of the vehicle by connecting the pump outlet to the second working chambers of the right and left dampers and connecting the pump inlet to the first working chambers of the right and left dampers. Finally, by connecting the pump outlet to the combination of the first working chamber of the left damper and the second working chamber of the right damper or to the combination of the first working chamber of the right damper and the second working chamber of the left damper, the control valve assembly provides anti-roll control and thus the mechanical stabilizer bar/anti-roll bar can be enhanced or replaced. When this occurs, both the static pressure in the system and the dynamic pressure generated by the pump are used to counteract the roll motion of the vehicle during cornering. Because the pump increases the pressure in the combination of the first working chamber of the left damper and the second working chamber of the right damper or the combination of the first working chamber of the right damper and the second working chamber of the left damper, the control valve assembly can control the suspension system so that the vehicle will lean to improve ride and handling performance.

Drawings

Other advantages will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a schematic diagram illustrating a vehicle equipped with two exemplary active suspension systems constructed in accordance with the present disclosure;

FIG. 2 is a schematic diagram illustrating one of the example active suspension systems shown in FIG. 1, wherein the active suspension system is configured to provide a comfort mode of operation;

FIG. 3 is a schematic diagram illustrating one of the example active suspension systems shown in FIG. 1, wherein the active suspension system is configured to provide a first pressure control mode of operation;

FIG. 4 is a schematic diagram illustrating one of the example active suspension systems shown in FIG. 1, wherein the active suspension system is configured to provide a second pressure control mode of operation;

FIG. 5 is a schematic diagram illustrating one of the example active suspension systems shown in FIG. 1, wherein the active suspension system is configured to provide a roll control mode of operation;

FIG. 6 is a schematic diagram illustrating one of the example active suspension systems shown in FIG. 1, wherein the active suspension system is configured to provide a ride height control mode of operation;

FIG. 7 is a schematic diagram illustrating an example valve block of one of the example active suspension systems shown in FIG. 1;

FIG. 8 is a schematic diagram showing an alternative active suspension system;

FIG. 9 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 8, wherein the active suspension system is configured to provide a passive roll control mode of operation;

FIG. 10 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 8, wherein the active suspension system is configured to provide a pressure control mode of operation;

FIG. 11 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 8, wherein the active suspension system is configured to provide an active roll control mode of operation;

FIG. 12 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 8, wherein the active suspension system is configured to provide a comfort mode of operation;

FIG. 13 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 8, wherein the active suspension system is configured to provide an alternative comfort mode of operation;

FIG. 14 is a schematic diagram showing another alternative active suspension system;

FIG. 15 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 14, wherein the active suspension system is configured to provide a comfort mode of operation;

FIG. 16 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 14, wherein the active suspension system is configured to provide a comfort mode of operation;

FIG. 17 is a schematic diagram illustrating the exemplary active suspension system shown in FIG. 14, wherein the active suspension system is configured to provide an alternative comfort mode of operation;

FIG. 18 is a schematic diagram showing another alternative active suspension system;

FIG. 19 is a schematic diagram showing another alternative active suspension system;

FIG. 20 is a schematic diagram showing another alternative active suspension system;

FIG. 21 is a schematic diagram showing another alternative active suspension system; and is

Fig. 22 is a schematic diagram illustrating another alternative active suspension system including a supplemental circuit.

Detailed Description

Referring to the drawings, wherein like numerals indicate corresponding parts throughout the several views, active suspension systems 34, 35 are disclosed.

Exemplary embodiments will now be described more fully with reference to the accompanying drawings. Exemplary embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may also be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Unless specifically identified as an order of execution, the method steps, processes, and operations described herein are not to be construed as necessarily requiring their execution in the particular order discussed or illustrated. It should also be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being "on," "engaged to," "connected to" or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between … …" versus "directly between … …", "adjacent" versus "directly adjacent", etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Although the terms "first," "second," "third," etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical values when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially relative terms (such as "inner," "outer," "lower," "below," "lower," "above," "upper," etc.) may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or oriented in other directions) and the spatially relative descriptors used herein interpreted accordingly.

Referring to FIG. 1, a vehicle 20 is shown having a front end 22 connected to a right front wheel 24 and a left front wheel 26, a rear end 28 connected to a right rear wheel 30 and a left rear wheel 32, a front active suspension system 34, and a rear active suspension system 35. A front active suspension system 34 is located at the front end 22 of the vehicle 20 and operates to control suspension motion and provide anti-roll control for the front wheels 24, 26 of the vehicle 20. A rear active suspension system 35 is located at the rear end 28 of the vehicle 20 and operates to control suspension movement and provide anti-roll control for the rear wheels 30, 32 of the vehicle 20.

In fig. 1, each of the active suspension systems 34, 35 includes a control valve assembly 36, 37 connected in fluid communication with a pump 38, 39 and a hydraulic reservoir 40, 41 (e.g., a tank). The control valve assembly 36 of the front active suspension system 34 is connected in fluid communication with a right front damper 42 and a left front damper 44. The control valve assembly 37 of the rear active suspension system 35 is connected in fluid communication with a right rear damper 43 and a left rear damper 45. The right front damper 42 controls (e.g., damps) the up-down (i.e., vertical) movement of the right front wheel 24 of the vehicle 20, and the left front damper 44 controls (e.g., damps) the up-down (i.e., vertical) movement of the left front wheel 26 of the vehicle 20. The right rear damper 43 controls (e.g., damps) the up-down (i.e., vertical) movement of the right rear wheel 30 of the vehicle 20, and the left rear damper 45 controls (e.g., damps) the up-down (i.e., vertical) movement of the left rear wheel 32 of the vehicle 20.

The anti-roll capability of the active suspension systems 34, 35 will be described in more detail below; however, it should be understood from fig. 1 that the front active suspension system 34 may operate independently of the rear active suspension system 35, and that both active suspension systems 34, 35 may be used to augment or completely replace the mechanical stabilizer/anti-roll bar. Such mechanical systems require relatively straight, unobstructed operation between each front damper and each rear damper. Accordingly, the active suspension systems 34, 35 disclosed herein provide packaging benefits because the front dampers 42, 44 need only be hydraulically connected to the front control valve assembly 36 and the rear dampers 43, 45 need only be hydraulically connected to the rear control valve assembly 37.

In the illustrated embodiment, the front and rear active suspension systems 34 and 35 are identical; however, other configurations are possible where the vehicle 20 includes only one of the active suspension systems 34, 35 or where the front active suspension system 34 is different from the rear active suspension system 35. The remainder of this application will discuss only the front active suspension system 34, it being understood that this may apply to the rear active suspension system 35.

Referring to fig. 2, each of the right and left dampers 42, 44 of the active suspension system 34 includes a damper housing 46, 47, a piston rod 48, 49, and a piston 50, 51 mounted on the piston rod 48, 49. The pistons 50, 51 are arranged in sliding engagement with the interior of the damper housings 46, 47 such that the pistons 50, 51 divide the damper housings 46, 47 into first and second working chambers 66, 70, 68, 72. The active suspension system 34 includes a plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64 connecting the pump 38, hydraulic reservoir 40, and right and left dampers 42, 44 to the control valve assembly 36. Although other configurations are possible, in the illustrated embodiment, the pistons 50, 51 in the dampers 42, 44 are closed pistons, with no fluid flow path within or defined by their structure.

The plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64 includes a first hydraulic line 52 extending between and fluidly connected to a first working chamber 66 of the right damper 42 and the control valve assembly 36. The plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64 includes a second hydraulic line 54 extending between and fluidly connecting a second working chamber 68 of the right damper 42 and the control valve assembly 36. The plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64 includes a third hydraulic line 56 extending between and fluidly connecting the first working chamber 70 of the left damper 44 and the control valve assembly 36. The plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64 includes a fourth hydraulic line 58 that extends between and fluidly connects a second working chamber 72 of the left damper 44 to the control valve assembly 36. The plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64 includes a fifth hydraulic line 60 and a sixth hydraulic line 62 that extend between and fluidly connect the pump 38 to the control valve assembly 36. The plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64 also includes a seventh hydraulic line 64 (i.e., an accumulator line) that extends between and fluidly connects the hydraulic accumulator 40 and the control valve assembly 36. In the example shown, hydraulic lines 52, 54, 56, 58, 60, 62, 64 are made of flexible tubing (e.g., hydraulic hoses), although other conduit structures and/or fluid passages may be used.

Control valve assembly 36 includes at least one valve block 74 having a plurality of valve block segments 76, 78, 80, 82, 84 (see fig. 7). The different valve block segments 76, 78, 80, 82, 84 present different combinations of fluid flow paths through the control valve assembly 36 that define different operating modes of the active suspension system 34. In the illustrated embodiment, a single valve block 74 is used with five valve block segments 76, 78, 80, 82, 84, but other configurations are possible.

Pump 38 includes a pump inlet 86 and a pump outlet 88. Pump inlet 86 is a port in pump 38 that draws hydraulic fluid. Pump outlet 88 is a port in pump 38 that discharges hydraulic fluid at a fluid pressure that is greater than the fluid pressure at pump inlet 86. The pump 38 in the illustrated example is a bi-directional electric pump 38. Thus, pump inlet 86 and pump outlet 88 are switched depending on the direction pump 38 is operating (i.e., depending on the polarity of the electricity provided to pump 38). Accordingly, any one of the fifth and sixth hydraulic lines 60 and 62 may operate as a pump suction line, and any one of the fifth and sixth hydraulic lines 60 and 62 may operate as a pump discharge line. In the example shown, when the pump 38 is operating in the forward direction, the fifth hydraulic line 60 operates as a pump discharge line and the sixth hydraulic line 62 operates as a pump suction line (fig. 4 and 5). When the pump 38 is operating in the opposite direction, the fifth hydraulic line 60 operates as a pump suction line and the sixth hydraulic line 62 operates as a pump discharge line (fig. 3 and 6). When the vehicle is turning, the lateral acceleration is measured by one or more sensors (not shown), and the anti-roll torque that controls the roll of the vehicle 20 is calculated by a controller (not shown) and used to control the pump 38. Alternatively, the lateral acceleration of the vehicle may be calculated by the controller based on the vehicle steering angle and the vehicle speed. The dampers 42, 44 serve to provide a force that counteracts the roll moment caused by the lateral acceleration, thereby reducing the roll angle.

The fifth hydraulic line 60 is connected to the first pressure reducing valve 90 through a first pressure reducing line 92, and the sixth hydraulic line 62 is connected to a second pressure reducing valve 94 through a second pressure reducing line 96. In other words, both the pump suction line and the pump discharge line are connected in fluid communication with the two pressure relief valves 90, 94. Each of the pressure reducing valves 90, 94 is configured to discharge (i.e., drain) hydraulic fluid into the hydraulic reservoir 40 when the fluid pressure in one of the fifth and sixth hydraulic lines 60, 62 exceeds the blow-out pressure. In the illustrated embodiment, the first pressure reducing valve 90 and the second pressure reducing valve 94 are configured to have the same blow-out pressure. For example, but not limiting of, the blow-off pressure may be set to 120 bar. However, it should be understood that other configurations are possible in which the blow-out pressure of the first pressure relief valve 90 is different from the blow-out pressure of the second pressure relief valve 94, or in which one of the pressure relief valves 90, 94 is eliminated.

The active suspension system 34 also includes four electro-mechanical valves 98, 100, 102, 104, two for each damper 42, 44. A first electro-mechanical valve 98 is positioned between the first working chamber 66 of the right damper 42 and the first hydraulic line 52. A second electromechanical valve 100 is positioned between the second working chamber 68 of the right damper 42 and the second hydraulic line 54. The third electro-mechanical valve 102 is positioned between the first working chamber 70 of the left damper 44 and the third hydraulic line 56. A fourth electro-mechanical valve 104 is positioned between the second working chamber 72 of the left damper 44 and the fourth hydraulic line 58. The electromechanical valves 98, 100, 102, 104 are semi-active valves having a combination of passive spring disc elements and solenoids. The electromechanical valves 98, 100, 102, 104 provide variable compression and rebound damping for each of the right 42 and left 44 dampers. For example, a controller (not shown) may be used to vary the current provided to the solenoids of the electromechanical valves 98, 100, 102, 104 to vary the damping characteristics of the right damper 42 and/or the left damper 44 (e.g., to soften or stabilize the ride).

The active suspension system 34 in the illustrated embodiment further includes a right accumulator 106 connected in fluid communication with the second hydraulic line 54 and a left accumulator 108 connected in fluid communication with the fourth hydraulic line 58. The right accumulator 106 and the left accumulator 108 may be configured in a number of different ways. For example, but not limiting of, right accumulator 106 and left accumulator 108 may have an accumulator chamber and a pressurized gas chamber separated by a floating piston or flexible membrane.

Referring to FIG. 2, active suspension system 34 is illustrated in a "comfort" mode of operation, wherein second section 78 of valve block 74 is connected in fluid communication with a plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64. The second section 78 of the valve block 74 includes an arrangement of fluid flow paths, wherein the first hydraulic line 52 is connected in fluid communication with the second hydraulic line 54, and wherein the third hydraulic line 56 is connected in fluid communication with the fourth hydraulic line 58. This creates two separate hydraulic circuits, one for each damper 42, 44.

According to this arrangement of the fluid flow path, the first and second working chambers 66, 68 of the right damper 42 are connected in fluid communication with each other and are fluidly isolated from the pump 38 and the left damper 44. Accordingly, hydraulic fluid may flow between the first and second working chambers 66, 68 of the right damper 42 via a hydraulic circuit including the first and second hydraulic lines 52, 54. Meanwhile, the first and second working chambers 70, 72 of the left damper 44 are connected in fluid communication with each other and are fluidly isolated from the pump 38 and the right damper 42. Accordingly, hydraulic fluid may flow between the first and second working chambers 70, 72 of the left damper 44 via a hydraulic circuit including the third and fourth hydraulic lines 56, 58.

The two hydraulic circuits are isolated from each other to fluidly isolate the right damper 42 from the left damper 44 such that when the active suspension system 34 is operating in a "comfort" mode of operation, the damping provided by the right damper 42 is independent of the damping provided by the left damper 44, and vice versa. In addition, the hydraulic circuit including the first and second hydraulic lines 52, 54 and the hydraulic circuit including the third and fourth hydraulic lines 56, 58 are fluidly isolated from the fifth, sixth, and seventh hydraulic lines 60, 62, 64 and thus operate as a closed loop system. Thus, the "comfort" mode of operation is optimized to improve ride comfort and stability when the vehicle 20 is traveling along a straight path. In this mode of operation, the pump 38 is turned off. In effect, active suspension system 34 operates in a "comfort" mode of operation as a suspension system without an anti-roll bar. It should be noted that this mode may also be activated when the vehicle 20 is operating off-road, where maximum suspension articulation is useful.

When the right damper 42 undergoes a compression stroke in the "comfort" mode of operation, fluid in the second working chamber 68 of the right damper 42 flows through the second electro-mechanical valve 100 and into the second hydraulic line 54. Fluid passes through the valve block 74, into the first hydraulic line 52, through the first electromechanical valve 98, and into the first working chamber 66 of the right damper 42. When the right damper 42 undergoes an extension (i.e., rebound) stroke in the "comfort" mode of operation, fluid in the first working chamber 66 of the right damper 42 flows through the first electromechanical valve 98 and into the first hydraulic line 52. Fluid passes through the valve block 74, into the second hydraulic line 54, through the second electro-mechanical valve 100, and into the second working chamber 68 of the right damper 42. When the left damper 44 undergoes a compression stroke in the "comfort" mode of operation, fluid in the second working chamber 72 of the left damper 44 flows through the fourth electro-mechanical valve 104 and into the fourth hydraulic line 58. Fluid passes through the valve block 74, into the third hydraulic line 56, through the third electro-mechanical valve 102, and into the first working chamber 70 of the left damper 44. When the left damper 44 undergoes an extension (i.e., rebound) stroke in the "comfort" mode of operation, fluid in the first working chamber 70 of the left damper 44 flows through the third electromechanical valve 102 and into the third hydraulic line 56. Fluid passes through valve block 74, into fourth hydraulic line 58, through fourth electro-mechanical valve 104, and into second working chamber 72 of left damper 44.

Referring to FIG. 3, the active suspension system 34 is illustrated in a "first pressure control" mode of operation, wherein the fifth section 84 of the valve block 74 is connected in fluid communication with the plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64. The fifth section 84 of the valve block 74 includes an arrangement of fluid flow paths in which the sixth hydraulic line 62 is connected in fluid communication with the second and fourth hydraulic lines 54, 58. In this mode of operation, the pump 38 is operated in the opposite direction, so that the sixth hydraulic line 62 serves as the pump discharge line and the fifth hydraulic line 60 serves as the pump suction line. The pump 38 discharges the hydraulic fluid into the sixth hydraulic line 62, which creates a high-pressure section consisting of the second, fourth and sixth hydraulic lines 54, 58, 62. Thus, pump outlet port 88 is connected in fluid communication with second working chamber 68 of right damper 42 and second working chamber 72 of left damper 44 through the high pressure section such that pump 38 increases the fluid pressure in second working chamber 68 of right damper 42 and second working chamber 72 of left damper 44. By way of example and not limitation, the pump 38 is operable to raise the fluid pressure in the high pressure section from 20 bar to 40 bar, which in turn will provide greater roll stiffness.

Depending on the arrangement of the fluid flow path through the fifth section 84 of the valve block 74, the fifth hydraulic line 60 is connected in fluid communication with the seventh hydraulic line 64, which allows the pump inlet 86 to draw hydraulic fluid from the hydraulic reservoir 40. Thus, the pump 38 creates a low pressure section comprised of the fifth and seventh hydraulic lines 60, 64 that is fluidly isolated from the high pressure section. In the arrangement of the fluid flow path through the fifth section 84 of the valve block 74, the first and third hydraulic lines 52, 56 are connected in fluid communication with each other, but are fluidly isolated from the high and low pressure sections. Thus, the pump 38 is fluidly isolated from the first working chambers 66, 70 of the right and left dampers 42, 44 and does not change the fluid pressure in the first and third hydraulic lines 52, 56. It will be appreciated that when the pump 38 is operated in the forward direction in this arrangement, the fifth hydraulic line 60 becomes the pump discharge line and the sixth hydraulic line 62 becomes the pump suction line. The pump 38 operates to reduce the fluid pressure in the second and fourth hydraulic lines 54, 58, and thus the second working chambers 68, 72 of the right and left dampers 42, 44 by pumping hydraulic fluid from these components back into the hydraulic reservoir 40.

Referring to FIG. 4, active suspension system 34 is illustrated in a "second pressure control" mode of operation, wherein fourth section 82 of valve block 74 is connected in fluid communication with the plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64. The fourth section of the valve block 74 includes an arrangement of fluid flow paths in which the fifth hydraulic line 60 is connected in fluid communication with the first and third hydraulic lines 52, 56. In this mode of operation, the pump 38 is operated in the forward direction, such that the fifth hydraulic line 60 serves as a pump discharge line and the sixth hydraulic line 62 serves as a pump suction line. The pump 38 discharges the hydraulic fluid into the fifth hydraulic line 60, which creates a high-pressure section consisting of the first, third and fifth hydraulic lines 52, 56, 60. Thus, the pump outlet port 88 is connected in fluid communication with the first working chamber 66 of the right damper 42 and the first working chamber 70 of the left damper 44 through the high pressure section, such that the pump 38 increases the fluid pressure in the first working chamber 66 of the right damper 42 and the first working chamber 70 of the left damper 44. By way of example and not limitation, the pump 38 is operable to raise the fluid pressure in the high pressure section from 20 bar to 40 bar, which in turn will provide greater roll stiffness.

Depending on the arrangement of the fluid flow path through the fourth section 82 of the valve block 74, the sixth hydraulic line 62 is connected in fluid communication with the seventh hydraulic line 64, which allows the pump inlet 86 to draw hydraulic fluid from the hydraulic reservoir 40. Thus, the pump 38 creates a low pressure section consisting of the sixth and seventh hydraulic lines 62, 64 that is fluidly isolated from the high pressure section. In the arrangement of the fluid flow path through the fourth section 82 of the valve block 74, the second and fourth hydraulic lines 54, 58 are connected in fluid communication with each other, but are fluidly isolated from the high and low pressure sections. Thus, the pump 38 is fluidly isolated from the second working chamber 68 of the right damper 42 and the second working chamber 72 of the left damper 44, and does not change the fluid pressures in the second hydraulic line 54 and the fourth hydraulic line 58. It will be appreciated that when the pump 38 is operated in the opposite direction in this arrangement, the sixth hydraulic line 62 becomes the pump discharge line and the fifth hydraulic line 60 becomes the pump suction line. The pump 38 operates to reduce the fluid pressure in the first and third hydraulic lines 52, 56, and thus the first working chambers 66, 70 of the right and left dampers 42, 44 by pumping hydraulic fluid from these components back into the hydraulic reservoir 40. The static pressure based base/passive roll stiffness in the active suspension system 34 can be adjusted by setting the pressure when the system 34 is in the first pressure control mode of operation and the second pressure control mode of operation.

Referring to fig. 5, the active suspension system 34 is illustrated in a "roll control" mode of operation wherein the third section 80 of the valve block 74 is connected in fluid communication with the plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64. The third section 80 of the valve block 74 includes an arrangement of fluid flow paths in which the second and third hydraulic lines 54, 56 are connected in fluid communication with each other, and in which the first and fourth hydraulic lines 52, 58 are connected in fluid communication with each other. The second and third hydraulic lines 54, 56 are connected in fluid communication with the fifth hydraulic line 60 by an arrangement of fluid flow paths in the third section of the valve block 74. The first and second hydraulic lines 52, 54 are connected in fluid communication with the sixth hydraulic line 62 by an arrangement of fluid flow paths in the third section 80 of the valve block 74. However, the second, third and fifth hydraulic lines 54, 56, 60 are fluidly isolated from the first, fourth and sixth hydraulic lines 52, 58, 62, and the seventh hydraulic line 64 is fluidly isolated from all of the other hydraulic lines 52, 54, 56, 58, 60, 62.

The arrangement of the fluid flow path through the third section 80 of the valve block 74 uses the static pressure in the active suspension system 34 to provide an anti-roll function. For example, when the vehicle 20 turns left, the lateral force causes the right side of the vehicle 20 to heel or lean, which compresses the right damper 42 and causes the left damper 44 to extend. When this occurs, the volume of fluid in the first working chamber 70 of the left damper 44 decreases, which sends hydraulic fluid into the third hydraulic line 56, through the third section 80 of the valve block 74, through the second hydraulic line 54 and into the second working chamber 68 of the right damper 42. This increases the pressure in the second working chamber 68 of the right damper 42, which stabilizes the right damper 42, counteracts the roll moment of the vehicle 20, and corrects the roll angle. The opposite occurs when the vehicle 20 is turning to the right. Because this anti-roll function operates using static pressure in the system, a fail-safe is provided in which the system operates to reduce body roll even when the pump 38 is not operating.

In the "roll control" mode of operation, active suspension system 34 combines the hydrostatic anti-roll function with the dynamic pressure provided by pump 38. In other words, the pump 38 is used to increase (i.e., lift) the pressure in the second and third hydraulic lines 54, 56 even further when the vehicle 20 is leaning to the right (i.e., when the vehicle 20 is turning to the left), and to increase the pressure in the first and fourth hydraulic lines 52, 58 when the vehicle 20 is leaning to the left (i.e., when the vehicle 20 is turning to the right). Fig. 5 shows a first scenario (i.e., a left turn of the vehicle 20). The pump 38 is operated in the forward direction such that the fifth hydraulic line 60 operates as a pump discharge line and the sixth hydraulic line 62 operates as a pump suction line. Thus, the pump outlet port 88 is connected in fluid communication with the first working chamber 70 of the left damper 44 and the second working chamber 68 of the right damper 42, and creates a high-pressure section made up of the second hydraulic line 54, the third hydraulic line 56, and the fifth hydraulic line 60. Meanwhile, the pump inlet 86 is connected in fluid communication with the first working chamber 66 of the right damper 42 and the second working chamber 72 of the left damper 44, and creates a low-pressure section constituted by the first hydraulic line 52, the fourth hydraulic line 58, and the sixth hydraulic line 62. This together creates a high pressure in the first working chamber 70 of the left damper 44 and the second working chamber 68 of the right damper 42, and a low pressure in the first working chamber 66 of the right damper 42 and the second working chamber 72 of the left damper 44. These pressure differences oppose the roll moment of the vehicle 20 and correct the roll angle. The dynamic pressure provided by the pump 38 may be even further and increase the pressure differential to the point where the vehicle 20 may lean to turn (e.g., lean to the left when the vehicle 20 turns left) to improve handling performance.

In a second scenario (i.e., in the case of a right turn of the vehicle 20), the polarity of the current supplied to the pump 38 is reversed such that the pump 38 is operating in the opposite direction. When this occurs, the fifth hydraulic line 60 operates as a pump suction line and the sixth hydraulic line 62 operates as a pump discharge line. Therefore, the pump outlet port 88 is connected in fluid communication with the first working chamber 66 of the right damper 42 and the second working chamber 72 of the left damper 44, and creates a high-pressure section constituted by the first hydraulic line 52, the fourth hydraulic line 58, and the sixth hydraulic line 62. Meanwhile, the pump inlet 86 is connected in fluid communication with the first working chamber 70 of the left damper 44 and the second working chamber 68 of the right damper 42, and creates a low-pressure section composed of the second, third and fifth hydraulic lines 54, 56 and 60. This together creates a high pressure in the first working chamber 66 of the right damper 42 and the second working chamber 72 of the left damper 44, and a low pressure in the first working chamber 70 of the left damper 44 and the second working chamber 68 of the right damper 42. These pressure differences oppose the roll moment of the vehicle 20 and correct the roll angle. Likewise, the dynamic pressure provided by the pump 38 may be even further and increase the pressure differential to a point where the vehicle 20 may be banked (e.g., banked to the right when the vehicle 20 is turning to the right) to improve handling performance.

Referring to fig. 6, active suspension system 34 is illustrated in a "ride height control" mode of operation wherein a first section 76 of valve block 74 is connected in fluid communication with a plurality of hydraulic lines 52, 54, 56, 58, 60, 62, 64. The first section 76 of the valve block 74 includes an arrangement of fluid flow paths. The fifth hydraulic line 60 is connected in fluid communication with the first and third hydraulic lines 52, 56, and wherein the sixth hydraulic line 62 is connected in fluid communication with the second and fourth hydraulic lines 54, 58. According to this arrangement, the first, third and fifth hydraulic lines 52, 56, 60 are fluidly isolated from the second, fourth and sixth hydraulic lines 54, 58, 62, and the seventh hydraulic line 64 is fluidly isolated from all other hydraulic lines 52, 54, 56, 58, 60, 62. In fig. 6, the pump 38 is shown running in the opposite direction, so that the sixth hydraulic line 62 acts as a pump discharge line and the fifth hydraulic line 60 acts as a pump suction line. The pump 38 discharges the hydraulic fluid into the sixth hydraulic line 62, which creates a high-pressure section consisting of the second, fourth and sixth hydraulic lines 54, 58, 62. Accordingly, pump outlet port 88 is connected in fluid communication with second working chamber 68 of right damper 42 and second working chamber 72 of left damper 44 through the high pressure section, and may increase the fluid pressure in second working chamber 68 of right damper 42 and second working chamber 72 of left damper 44. The pump 38 draws hydraulic fluid from the fifth hydraulic line 60, which creates a low pressure section consisting of the first, third and fifth hydraulic lines 52, 56, 60. Thus, the pump inlet 86 is connected in fluid communication with the first working chamber 66 of the right damper 42 and the first working chamber 70 of the left damper 44 through the low pressure section, and the fluid pressure in the first working chamber 66 of the right damper 42 and the first working chamber 70 of the left damper 44 can be reduced. The pressure differences between the first and second working chambers 66, 68, 70, 72 in the right and left dampers 42, 44 operate together to lift (i.e., raise) the vehicle 20 to increase the ride height. This can be used to provide improved ground clearance during off-road operations or for low-ride vehicles when traversing speed bumps.

The active suspension system 34 may also be operated with the pump 38 running in the forward direction, such that the fifth hydraulic line 60 serves as the pump discharge line and the sixth hydraulic line 62 serves as the pump suction line. With this arrangement, the pump 38 discharges hydraulic fluid into the fifth hydraulic line 60, which creates a high-pressure section consisting of the first, third and fifth hydraulic lines 52, 56, 60. Accordingly, the pump outlet port 88 is connected in fluid communication with the first working chamber 66 of the right damper 42 and the first working chamber 70 of the left damper 44 through the high pressure section, and the fluid pressure in the first working chamber 66 of the right damper 42 and the first working chamber 70 of the left damper 44 can be increased. The pump 38 draws hydraulic fluid from the sixth hydraulic line 62, which creates a low pressure section consisting of the second, fourth and sixth hydraulic lines 54, 58, 62. Thus, the pump inlet 86 is connected in fluid communication with the second working chambers 68, 72 of the right and left dampers 42, 44 through the low pressure section, and the fluid pressure in the second working chambers 68, 72 of the right and left dampers 42, 44 can be reduced. The pressure differences between the first and second working chambers 66, 68, 70, 72 in the right and left dampers 42, 44 operate together to lower the vehicle 20, thereby reducing the ride height. This may be used to improve cornering performance or to provide easier passenger ingress and egress for high ride vehicles.

Referring to FIG. 7, each valve block segment 76, 78, 80, 82, 84 in the valve block 74 includes seven connections 110a-e, 112a-e, 114a-e, 116a-e, 118a-e, 120a-e, 122a-e, one for each of the first hydraulic line 52, the second hydraulic line 54, the third hydraulic line 56, the fourth hydraulic line 58, the fifth hydraulic line 60, the sixth hydraulic line 62, and the seventh hydraulic line 64. Four connections 114a-e, 116a-e, 118a-e, 120a-e may be provided on one side of each valve block section 76, 78, 80, 82, 84, and three connections 110a-e, 112a-e, 122a-e may be provided on the opposite side of each valve block section 76, 78, 80, 82, 84, although other configurations are possible. Control valve assembly 36 controls which operating mode is selected by operatively connecting hydraulic lines 52, 54, 56, 58, 60, 62, 64 to connections 110a-e, 112a-e, 114a-e, 116a-e, 118a-e, 120a-e, 122a-e of one of valve block segments 76, 78, 80, 82, 84, but not to the other connections. In other words, the control valve assembly 36 switches which valve block segments 76, 78, 80, 82, 84 are connected in fluid communication with the hydraulic lines 52, 54, 56, 58, 60, 62, 64. In the example shown, the connectors 110a-e, 112a-e, 114a-e, 116a-e, 118a-e, 120a-e, 122a-e are shown as parts, but other connection configurations may be used.

The first valve block section 76 comprises a first connection 110a configured to be connected to the first hydraulic line 52, a second connection 112a configured to be connected to the second hydraulic line 54, a third connection 114a configured to be connected to the third hydraulic line 56, a fourth connection 116a configured to be connected to the fourth hydraulic line 58, a fifth connection 118a configured to be connected to the fifth hydraulic line 60, a sixth connection 120a configured to be connected to the sixth hydraulic line 62, and a seventh connection 122a configured to be connected to the seventh hydraulic line 64. The first valve block section 76 comprises an arrangement of fluid flow paths wherein a first connection 110a, a third connection 114a and a fifth connection 118a are interconnected, and wherein a second connection 112a, a fourth connection 116a and a sixth connection 120a are interconnected. The seventh connection 122a is closed and thus fluidly isolated.

The second valve block section 78 comprises a first connection 110b configured to be connected to the first hydraulic line 52, a second connection 112b configured to be connected to the second hydraulic line 54, a third connection 114b configured to be connected to the third hydraulic line 56, a fourth connection 116b configured to be connected to the fourth hydraulic line 58, a fifth connection 118b configured to be connected to the fifth hydraulic line 60, a sixth connection 120b configured to be connected to the sixth hydraulic line 62, and a seventh connection 122b configured to be connected to the seventh hydraulic line 64. The second valve block section 78 comprises an arrangement of fluid flow paths, wherein the first connection 110b and the second connection 112b are interconnected, and wherein the third connection 114b and the fourth connection 116b are interconnected. The fifth, sixth and seventh connections 118b, 120b, 122b are closed and thus fluidly isolated.

The third valve block section 80 includes a first connection 110c configured to be connected to the first hydraulic line 52, a second connection 112c configured to be connected to the second hydraulic line 54, a third connection 114c configured to be connected to the third hydraulic line 56, a fourth connection 116c configured to be connected to the fourth hydraulic line 58, a fifth connection 118c configured to be connected to the fifth hydraulic line 60, a sixth connection 120c configured to be connected to the sixth hydraulic line 62, and a seventh connection 122c configured to be connected to the seventh hydraulic line 64. The third valve block section 80 comprises an arrangement of fluid flow paths wherein a second connection 112c, a third connection 114c and a fifth connection 118c are interconnected, and wherein a first connection 110c, a fourth connection 116c and a sixth connection 120c are interconnected. The seventh connection 122c is closed and thus fluidly isolated.

The fourth valve block section 82 comprises a first connection 110d configured to be connected to the first hydraulic line 52, a second connection 112d configured to be connected to the second hydraulic line 54, a third connection 114d configured to be connected to the third hydraulic line 56, a fourth connection 116d configured to be connected to the fourth hydraulic line 58, a fifth connection 118d configured to be connected to the fifth hydraulic line 60, a sixth connection 120d configured to be connected to the sixth hydraulic line 62, and a seventh connection 122d configured to be connected to the seventh hydraulic line 64. The fourth valve block section 82 comprises an arrangement of fluid flow paths, wherein the first, third and fifth connections 110d, 114d, 118d are interconnected, wherein the sixth and seventh connections 120d, 122d are interconnected, and wherein the second and fourth connections 112d, 116d are interconnected.

The fifth valve block section 84 comprises a first connection 110e configured to be connected to the first hydraulic line 52, a second connection 112e configured to be connected to the second hydraulic line 54, a third connection 114e configured to be connected to the third hydraulic line 56, a fourth connection 116e configured to be connected to the fourth hydraulic line 58, a fifth connection 118e configured to be connected to the fifth hydraulic line 60, a sixth connection 120e configured to be connected to the sixth hydraulic line 62, and a seventh connection 122e configured to be connected to the seventh hydraulic line 64. Fifth valve block segment 84 comprises an arrangement of fluid flow paths wherein second connection 112e, fourth connection 116e, and sixth connection 120e are interconnected, wherein first connection 110e and third connection 114e are interconnected, and wherein fifth connection 118e and seventh connection 122e are interconnected.

Fig. 8-13 depict an alternative active suspension system 130 located at the front end 22 of the vehicle 20 to operate and control suspension movement and provide anti-roll control for the front wheels 24, 26 of the vehicle 20. It should be appreciated that active suspension system 130 may also be configured to control the rear wheels of vehicle 20, if desired. The active suspension system 130 may include the same or similar right front damper 42 and left front damper 44 as previously described. While the active suspension system 130 may function substantially the same or similar to the active suspension systems 34, 35, the components interconnecting the right and left dampers 42, 44 are different from those previously described.

The active suspension system 130 includes a control valve system including a first control valve 132, a second control valve 134, a third control valve 136, a fourth control valve 138, a fifth control valve 140, and a sixth control valve 142 in fluid communication with a pump 144 and a hydraulic fluid reservoir 146. A plurality of hydraulic lines 150, 152, 154, 156, 158, 160, and 162 hydraulically connect the control valves 132, 134, 136, 138, 140, 142 to the right and left dampers 42, 44, the pump 144, and the hydraulic fluid reservoir 146.

A hydraulic line 150 extends between and fluidly interconnects the first working chamber 70 of the left damper 44 and the second chamber 68 of the right damper 42. A hydraulic line 152 extends between and fluidly interconnects the first working chamber 66 of the right damper 42 and the second working chamber 72 of the left damper 44. A hydraulic line 154 extends between and fluidly interconnects the hydraulic line 150 and the third control valve 136. A hydraulic line 156 extends between and fluidly interconnects the hydraulic line 152 and the fourth control valve 138. The hydraulic line 156 also interconnects the hydraulic line 152 with the sixth control valve 142. Hydraulic line 158 interconnects third control valve 136, fourth control valve 138, and first port 164 of pump 144. A hydraulic line 160 interconnects the fifth control valve 140, the sixth control valve 142, and a second port 166 of the pump 144.

The first control valve 132 is positioned between and selectively fluidly interconnects the hydraulic lines 150 and 152. The second control valve 134 is positioned between and selectively fluidly interconnects the hydraulic lines 152 and 150. A hydraulic line 162 fluidly interconnects the accumulator 146 with the fifth control valve 140. It should be understood that hydraulic lines 150, 152, 154, 156, 158, 160, and 162 may be constructed of rigid lines, flexible tubes, hoses, and the like.

Each control valve is substantially similar to the other control valve, wherein each control valve is a spring-biased two-position solenoid operated valve. Each valve is spring biased to a closed position. When energized, the solenoid causes an internal component within the valve (such as a translatable spool) to move to an open position. When in the closed position, fluid may not pass through the control valve. When in the open position, fluid is allowed to pass freely through the control valve. Valve structures other than a valve spool may also be used, including but not limited to poppet valves. While the control valves are described as being solenoid operated, they may be operated by other electrical configurations or using energy other than electrical energy.

The pump 144 includes a first pump port 166 and a second pump port 164. It should be appreciated that since the pump 144 is a bi-directional pump, the pump ports serving as the inlet and the pump ports on the pump 144 and the pump port serving as the outlet may be switched when the rotational direction of the motor 168 driving the pump 144 is reversed. For example, when the motor 168 is driven in the first direction and the fifth control valve 140 is open, fluid is drawn from the hydraulic fluid reservoir 146 to the pump port 166 through the hydraulic line 160. The pump port 166 acts as a pump inlet during this portion of operation. The pressurized fluid exits the pump port 164 which serves as a pump outlet. In a different mode of operation, described below, the motor 168 is driven in a second, opposite direction to draw fluid from the hydraulic line 158 into the port 164, which now serves as the pump inlet. The pressurized fluid exits the pump port 166 which serves as a pump outlet.

The active suspension system 130 also includes a first flow control valve 180, a second flow control valve 182, a third flow control valve 184, and a fourth flow control valve 186. The first flow control valve is fluidly interconnected thereto and is in fluid communication with the first working chamber 70 and the hydraulic line 150. A second flow control valve is positioned between and in fluid communication with second working chamber 72 and hydraulic line 152. A third flow control valve 184 is positioned between and in fluid communication with the first working chamber 66 and the hydraulic line 152. Fourth flow control valve 186 is positioned between and in fluid communication with second working chamber 68 and hydraulic line 150. The flow control valve may be configured as a hydraulic passive valve or as a semi-active hydraulic valve. Thus, if the flow control valve is configured as a passive valve, the flow control valve need not receive an electrical signal.

The active suspension system 130 may also include a first accumulator 192, a second accumulator 194, a third accumulator 186, and a fourth accumulator 198. First accumulator 192 is in fluid communication with line 152. The second accumulator 194 is in fluid communication with the hydraulic line 150. The third accumulator 196 is in fluid communication with the hydraulic line 154. The fourth accumulator 198 is in fluid communication with the hydraulic line 156. The first pressure sensor 202 is operable to output a signal indicative of the pressure within the hydraulic line 154. Second pressure sensor 204 is operable to output a signal indicative of the pressure within hydraulic line 156.

It should be appreciated that active suspension system 130 may operate in four different operating modes. The passive roll control mode may be used to reduce the vehicle roll angle while turning. By reducing the roll angle of the vehicle, the driver and passengers may experience increased comfort, steering feel, and other positive experiences including increased vehicle capability and stability. Passive roll control is provided by filling the active suspension system 130 with a predetermined fluid pressure and mechanically capturing pressurized fluid in communication with the dampers 42, 44.

The pressure control mode may be used to charge the system with pressurized fluid and to provide temperature compensation. The pressure control mode may be entered to perform a vehicle lifting or vehicle lowering operation.

An active roll control mode is also available. When the pump 144 is energized to output pressurized fluid to one of the hydraulic lines 150 and 152, the active suspension system 130 may apply an anti-roll torque. If desired, the active suspension system 130 may apply a negative roll angle. Anti-roll torque may be applied to reduce body oscillations, resulting in an improved ride experience. When compared with a conventional vehicle equipped with a passive mechanical stabilizer bar, the overall vehicle roll stiffness is increased.

Active suspension system 130 is configured to operate in a third mode or comfort mode. In the comfort mode of operation, the control valve assembly of the control valve system is opened to minimize resistance to fluid flow therethrough and between the right and left dampers 42, 44. The following is a detailed description of each mode of operation.

Table 1 provides a state diagram as a quick overview of the valve and pump motor operating states that may be used to achieve the desired operating mode of the active suspension system 130 identified as configuration 1. Table 1 shows the control valves and abbreviated nomenclature of the control valve positions. C1 denotes the first control valve 132. C2 identifies the second control valve 134. C3 relates to the third control valve 136. C4 identifies the fourth control valve 138. C5 corresponds to the fifth control valve 140 and C6 identifies the sixth control valve 142. Reference numeral 1 indicates that the valve is in an open position, allowing fluid to pass therethrough. Reference numeral 0 denotes the valve being de-energized and closed. In some modes of operation, table 1 indicates "pump locked". Any number of mechanical locking systems may be employed to limit rotation of the electric motor 168 or internal components of the pump 144 to prevent fluid from passing through the pump 144. Alternatively, an electric brake may be applied to the electric motor 168 to limit its and pump 144 rotation. Conversely, entries in table 1 that set forth that the pump is free running indicate that the internal components of the pump 144 are allowed to move and allow fluid to pass through the pump 144.

TABLE 1

Fig. 9 depicts the active suspension system 130 operating in a passive roll control mode during a right turn. The forward direction of vehicle travel is the top of the page. At this point the motor 168 is de-energized and the pump 144 does not provide additional pressurized fluid to the system. Each of the first, second, third, fourth, fifth, and sixth control valves 132, 134, 136, 138, 140, 142 are de-energized and in a normally closed position. With the control valves in the foregoing positions, the hydraulic line 150 defines a first circuit interconnecting the first working chamber 70 of the left damper 44 with the second working chamber 68 of the right damper 42. The second independent circuit is defined by a hydraulic line 152 interconnecting the first working chamber 66 of the right damper 42 with the second working chamber 72 of the left damper 44. When the vehicle turns right, the center of gravity of the vehicle 20 exerts a load on the left damper 44, attempting to drive the piston 51 downward in the drawing. At the same time, the piston 50 of the right damper 42 is pushed upward in the drawing. The pressure in the hydraulic line 152 increases to resist movement of each piston 50, 51 in that direction. Passive roll control is achieved.

The first and second accumulators 192, 194 are positioned within the hydraulic lines 152, 150, respectively, to minimize the magnitude of any spikes in pressure waves that may occur during vehicle operation. The accumulator is optional, but can improve ride quality by allowing each damper to function somewhat independently of the other, while providing passive roll control.

Fig. 10 illustrates a pressure control mode in which the static pressure within the active suspension system 130 may be set. The first accumulator 192 and the second accumulator 194 may be filled with a predetermined pressure by setting a control valve as shown in the figure. Specifically, the first, second, third, fourth, and fifth control valves 132, 134, 136, 138, 140 are energized and set to an open position. If it is desired to increase the pressure within the system, the motor 168 is driven in a direction to draw fluid from the hydraulic fluid reservoir 146, with the pump port 166 serving as a pump inlet. The pump port 164 serves as a pump outlet. Pressurized fluid is supplied to both the hydraulic line 150 and the hydraulic line 152. To reduce the pressure within the active suspension system 130, the same valve is energized to an open position, but the motor 168 is driven in the opposite direction to pump fluid from the hydraulic line 150 and the hydraulic line 152 into the hydraulic fluid reservoir 146. When reducing static pressure in the system, pump port 164 serves as a pump inlet and pump port 166 serves as a pump outlet. Once the desired fill pressure is set, the control valve may return to the passive roll control configuration previously described or any other configuration described below.

The pressure control mode depicted in fig. 10 may also be used in other situations rather than simply setting the fill pressure of the active suspension system 130. For example, it may be desirable to compensate for ambient temperature variations in the operation of active suspension system 130. If the temperature rise applies increased pressure to the hydraulic line 150, the hydraulic line 152, or both, the pump 144 may be driven to reduce the pressure in either or both of the hydraulic lines 150, 152. If the temperature drop undesirably reduces the pressure within the system, the pump 144 may be driven to add pressure in either or both of the hydraulic lines 150, 152.

Another alternative function relating to vehicle ride height may be provided. The vehicle may be raised or lowered relative to the ground based on the magnitude of the pressure present within the active suspension system 130. Control of the control valves and pump 144 may be performed as previously described with respect to increasing or decreasing static pressure within the active suspension system 130.

The operating mode of the active suspension system 130 may be switched from the passive roll control mode to the active roll control mode by energizing one of the third and fourth control valves 136, 138 and the sixth control valve 142 to place the valves in an open position. The remaining control valves maintain their closed positions. Fig. 11 depicts a situation where it is desired to pressurize the first working chamber 66 of the right damper 42 and the second working chamber 72 of the left damper 44. This type of control may be desired during a right turn of the vehicle, and is achieved by energizing the third and sixth control valves 136, 142 while energizing the motor 168 to drive the pump 144 such that the port 164 serves as the pump inlet and the port 166 serves as the pump outlet. The hydraulic line 152 receives high pressure. Hydraulic line 150 experiences a lower fluid pressure. It should be noted that the fifth control valve 140 is maintained in a closed position such that hydraulic fluid from the reservoir 146 is not drawn into the pump 144. The fluid supply for the pump 144 is provided by a hydraulic line 150.

Similarly, but not depicted in fig. 11, the active roll control may include energizing the fourth and sixth control valves 138, 142. The third control valve 136 is held in a closed position. In this case, hydraulic line 150 receives pressurized fluid from port 164 of pump 144. The upper working chamber 70 of the left damper 44 and the lower working chamber 68 of the right damper 42 are highly pressurized, while the hydraulic line 152, the upper working chamber 66 of the right damper 42 and the lower working chamber 72 of the left damper 44 experience a lower fluid pressure. This type of active roll control may be desirable when the vehicle is experiencing a left turn.

FIG. 12 illustrates one method of operating the active suspension system 130 in a comfort mode. The first and second control valves 132, 134 are moved to an open position to interconnect the hydraulic lines 150, 152 at two separate locations. The first control valve 132 may be positioned adjacent the left damper 44 to minimize the distance traveled therebetween. Similarly, the second control valve 134 may be positioned adjacent the right damper 42 to minimize the conduit length between the right damper 42 and the second control valve 134. To further reduce the restriction of fluid within the active suspension system 130, the third control valve 136 and the fourth control valve 138 are energized to an open position. In this manner, active suspension system 130 applies minimal resistance to translation of piston rod 48 in right damper 42 and piston rod 49 in left damper 44. Ride performance is defined by the basic operating characteristics of the right damper 42, the left damper 44, and any mechanical (spring or lever) configuration of the suspension.

Fig. 13 depicts an alternative way of placing the active suspension system 130 in a comfort mode of operation. As previously described, the first and second control valves 132, 134 are energized to an open position to interconnect the hydraulic lines 150, 152 at two separate locations. The third control valve 136 and the sixth control valve 142 are energized to place the valves in an open position and allow fluid to pass through the pump 144. It may be desirable to allow fluid to pass through the pump 144 while de-energizing the pump. The inertial characteristics of the internal components of the pump will serve to slightly restrict flow and provide a slightly modified comfort mode. To further customize the comfort mode from a wide open straight-through system to a more restricted flow configuration, the electric motor 168 may be energized at a duty cycle of less than 100%. The pump may be energized in a certain direction to restrict flow therethrough. A customized amount of resistance to fluid flow may be provided to adjust the comfort operating mode to the target of a particular vehicle or operator.

Fig. 14 depicts an alternative configuration active suspension system identified by reference numeral 200. Active suspension system 200 is a simplified system that includes four two-position directional control valves instead of the six control valve systems previously described. The active suspension system 200 can provide substantially the same functionality previously described with reduced cost and complexity. Active suspension system 200 is substantially the same as active suspension system 130 except that first control valve 132 and second control valve 134 have been removed. For clarity, similar elements will retain their previously introduced reference numerals, including the prime suffix.

The active suspension system 200 may be placed in the passive roll control mode according to a first method by allowing each of the third, fourth, fifth, and sixth control valves 136 ', 138', 140 ', 142' to be in a de-energized closed position. The pump 144' is de-energized. An alternative second method of providing passive roll control is achieved by energizing the third and sixth control valves 136 ', 142'. When utilizing the second method for passive roll control, the pump 144 'is locked such that fluid is not allowed to pass through the pump 144'. Table 2 provides a state diagram indicating the state of each control valve of active suspension system 200 (configuration 2) to provide a certain mode of operation. Table 2 presents control valves and abbreviated representations of control valve positions. C3 relates to the third control valve 136'. C4 identifies the fourth control valve 138'. C5 corresponds to the fifth control valve 140 'and C6 identifies the sixth control valve 142'. Reference numeral 1 indicates that the valve is in an open position, allowing fluid to pass therethrough. Reference numeral 0 denotes the valve being de-energized and closed.

TABLE 2

The active suspension system 200 can also operate in an active roll control mode. Table 2 indicates that the hydraulic line 150 is selectively energized by opening the third control valve 136 'and the sixth control valve 142'. The pump 144 transfers fluid from the hydraulic line 150 'to the hydraulic line 152'. This energization scheme may correspond to providing roll control when the vehicle is turning right. If it is desired to operate the active suspension system 200 in the active roll control mode during a left turn, the fourth control valve 138 'is energized open and the third control valve 136' is placed in a closed position.

Fig. 15 depicts an active suspension system 200 operating in a first method of achieving a comfort mode of operation. The third control valve 136 'and the fourth control valve 138' are placed in an open position to allow fluid to pass between the hydraulic line 150 'and the hydraulic line 152'. The pump 144' is not energized. Fluid may flow freely between the left damper 44 'and the right damper 42'.

A second method of operating the active suspension system 200 in a comfort mode is illustrated in fig. 16. Comfort mode operation is achieved by: placing the third control valve 136 'in an open position, placing the sixth control valve 142' in an open position, and allowing internal components of the pump 144 'to move and allow fluid to pass through the pump 144' when de-energized.

Fig. 17 illustrates an active suspension system 200 operating in a pressure control mode. To fill or increase the static pressure within the active suspension system 200, the pump 144 'is driven to draw low pressure fluid from the hydraulic fluid reservoir 146' and supply pressurized fluid to both the hydraulic line 150 'and the hydraulic line 152'. To reduce the static pressure within the active suspension system 200, the valve state remains the same as depicted in fig. 17, but the pump 144 'is driven in the opposite direction to transfer fluid from both the hydraulic line 150' and the hydraulic line 152 'to the hydraulic fluid reservoir 146'.

Another alternative active suspension system is identified by the reference numeral 250 shown in fig. 18. Active suspension system 250 utilizes only three directional control valves. Many alternative active suspension systems 250 include the same components as the suspension systems 130, 200 previously described herein. Accordingly, like elements will retain their previously introduced reference numerals with a double primed suffix.

The active suspension system 250 includes a first control valve 132 "and a second control valve 134". A two-position, five-port directional control valve 254 is also provided. Active suspension system 250 includes improved hydraulic line routing. On top of the directional control valve 254, as shown in fig. 18, three ports are provided. The first port 260 is placed in fluid communication with the hydraulic fluid reservoir 146 "through a hydraulic line 264. The hydraulic line 154 "interconnects the second port 268 of the directional control valve 254 with the hydraulic line 150". Hydraulic line 156 "fluidly interconnects hydraulic line 152" with a third port 272 of directional control valve 254. On the bottom side of directional control valve 254, as depicted in fig. 18, fourth port 276 is fluidly coupled to pump port 164 "via hydraulic line 280. The fifth port 284 of the directional control valve 254 is fluidly coupled to the pump port 166 "via a hydraulic line 288.

Fig. 19 depicts another alternative active suspension system at 300. Active suspension system 300 is a minor variation of active suspension system 250 in which directional control valve 254 is replaced by directional control valve 302. The directional control valve 302 is a three-position, five-port directional control valve. The first two positions are the same as previously described with respect to directional control valve 254. The third position has all ports blocked.

Table 3 provides a state diagram associated with active suspension system 250 (configuration 3-1) shown in fig. 18 and active suspension system 300 (configuration 3-2) shown in fig. 19. Interestingly, the active suspension systems 250, 300 may be configured without the first control valve 132 "and the second control valve 134". Table 3 provides state diagram information for alternative systems 250, 300 with and without the first control valve 132 "and the second control valve 134" (without C1 and C2). In some modes of operation, table 3 indicates "pump locked".

Any number of mechanical locking systems may be employed to limit rotation of the internal components of the electric motor 168 "or the pump 144" to prevent fluid from passing through the pump 144 ". One arrangement includes using the pump as an inerter. Alternatively, an electric brake may be applied to the electric motor 168 "to limit its rotation with the pump 144". In another embodiment, the rotation of the pump may be limited by employing a circuit that causes the electric motor 168 "to function as a generator. Conversely, entries in table 3 that set forth the pump as free running indicate that the internal components of pump 144 "are allowed to move and fluid is allowed to pass through pump 144".

TABLE 3

Fig. 20 depicts another alternative active suspension system (configuration 4-1) identified by reference numeral 350. The active suspension system 350 replaces the four directional control valves having reference numbers 136, 138, 140, and 142 with a two-position three-port directional control valve 352 and a two-position three-port directional control valve 354. For consistency and ease of explanation, elements previously discussed will retain their original reference numerals and triple primed suffixes.

The directional control valve 352 includes a first port 360, a second port 364, and a third port 366. Hydraulic line 154 "'interconnects hydraulic line 150"' with first port 360. A hydraulic line 370 interconnects the hydraulic line 152 "' with the second port 364. A hydraulic line 374 interconnects the third port 366 with 164 "'of the pump 144"'. The directional control valve 354 includes a first port 380, a second port 384, and a third port 386. Hydraulic line 156 "'interconnects hydraulic line 152"' with first port 380. A hydraulic line 390 interconnects the second port 384 with the hydraulic fluid reservoir 146 "'. A hydraulic line 394 interconnects the third port 386 with the pump port 166 "'.

Active suspension system 350 can operate in various modes as previously described. Table 4 provides a state diagram for operating the various control valves and pumps to achieve the desired operating mode. It should be appreciated that the active suspension system 350 may be configured with or without the first control valve 132 "'(C1) and the second control valve 134"' (C2). Table 4 illustrates these two systems. The active suspension system 350 may provide roll control by placing the directional control valve 352(DV1) and the directional control valve 354(DV2) in the second position. If present, the first control valve 132 "'of the second control valves 134"' remains in the de-energized closed position. To implement active roll control, the pump motor 168' "is energized. To achieve passive roll control, the pump 144 "' is placed in a locked position to restrict flow through the pump.

TABLE 4

The active suspension system 350 may operate in a comfort mode by placing the first and second control valves 132 "'and 134"' in an open position (if so equipped). Both the directional control valve 352 and the directional control valve 354 may be placed in the second position, or the directional control valve 352 may be placed in position one and the directional control valve 354 placed in position two. Pump 144 "' is de-energized and left in the free running mode. The pressure control mode may be provided by opening first control valve 132 "'and second control valve 134"' and setting directional control valve 352 and directional control valve 354 in the first position. The static pressure within the active suspension system 350 may increase or decrease based on the direction in which the pump 144 "' is driven.

Fig. 21 shows another alternative embodiment suspension system 400. Active suspension system 400 is substantially similar to active suspension system 350 except that a three-position, three-port directional control valve 402 is substituted for directional control valve 352. The third position on the directional control valve 402 blocks all ports to disconnect the pump from the hydraulic lines 150 "'and 152"'. Passive roll control may be achieved by utilizing a third position on the directional control valve 402 to restrict flow through the pump 144' "without relying on a pump locking mechanism. Table 5 shows the various states for achieving the desired operation of the valves and pump control of active suspension system 400 (configuration 4-2). Suspension system 400 may be configured with or without first control valve 132 "'and second control valve 134"' as shown in table 5.

TABLE 5

It should be understood that various vehicle specifications and requirements will define the particular active control system implemented. Some of the foregoing components may be omitted or replaced. For example, the accumulators 196, 198 may be eliminated if the fluid fluctuations occurring within the hydraulic line 154 and the hydraulic line 156 exhibit sufficiently low magnitudes. The variable flow control valves 180, 182, 184, and 186 may be configured as semi-active hydraulic valves or conventional passive valves.

Fig. 22 depicts a supplemental circuit 450 that may be added to any of the aforementioned active suspension systems. This figure shows the active suspension system 130 (fig. 8) modified and now identified as 130A to include a supplemental circuit 450 and a similar supplemental circuit 452. The supplemental circuits 450, 452 may be operated individually to reduce single wheel stiffness at any given wheel, thereby increasing comfort. The supplemental circuit 450 includes a check valve 454 having an adjustable cracking pressure, an accumulator 458, a one-way check valve 462, and a flow control valve 466. The supplemental circuit 450 is used to allow fluid to flow to the accumulator 458 immediately after the time that the right front wheel 24 is impacted by an obstacle or by any change in the seating surface that results in a pressure spike. Fluid exiting accumulator 458 flows through flow control valve 466 and check valve 462 to return to hydraulic line 150. Because a portion of the fluid rapidly exiting the second working chamber 68 of the right damper 42 passes through the makeup circuit 450, undesirable pressure spikes will not be transferred to the first working chamber 70 of the left damper 44. Thus, the individual input stiffness is reduced and occupant comfort is increased.

It should also be understood that the disclosed suspension system may be configured to provide any combination of all of the various modes and their respective functions or less than all of the modes and respective functions. By selecting among these combinations, suspension system providers and vehicle manufacturers can manufacture systems and vehicles with different performance capabilities available at different costs or pricing levels based on the selected combination of available modes and functions. The availability of modes and corresponding functions may be determined by the structure of the system or by software enabled activation of the modes and functions. Where software is enabled, the available modes and corresponding functions may be determined during manufacture of the vehicle having the suspension system, in connection with delivery of the vehicle to a purchaser (e.g., a dealer or customer), or after delivery to the vehicle purchaser.

Many other modifications and variations of the present disclosure are possible in light of the above teachings and may be practiced otherwise than as specifically described within the scope of the appended claims.