Patent Publication Number: US-2019176557-A1

Title: Active valve for an internal bypass

Description:
This application is a continuation-in-part application of and claims priority to and benefit of co-pending U.S. patent application Ser. No. 16/044,380, filed on Jul. 24, 2018 entitled, “ADJUSTABLE INTERNAL BYPASS” by John Marking, having Attorney Docket No. FOX-P5-6-14-US.CON2, assigned to the assignee of the present application, and incorporated herein, in its entirety, by reference. 
     The application with Ser. No. 16/044,380 is a continuation application of and claims priority to and benefit of U.S. patent application Ser. No. 15/387,236, filed on Sep. 16, 2014, now U.S. Issued U.S. Pat. No. 10,040,328, entitled, “ADJUSTABLE INTERNAL BYPASS” by John Marking, having Attorney Docket No. FOX-P5-6-14-US.CON, assigned to the assignee of the present application, and incorporated herein, in its entirety, by reference. 
     The application with Ser. No. 15/387,236 is a continuation application of and claims priority to and benefit of U.S. patent application Ser. No. 14/487,529, filed on Sep. 16, 2014, now U.S. Issued U.S. Pat. No. 9,528,565, entitled, “ADJUSTABLE INTERNAL BYPASS” by John Marking, having Attorney Docket No. FOX-P5-6-14-US, assigned to the assignee of the present application, and incorporated herein, in its entirety, by reference. 
     This application is a continuation-in-part application of and claims the benefit of co-pending U.S. patent application Ser. No. 16/042,563, filed on Jul. 23, 2018, entitled “METHOD AND APPARATUS FOR AN ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-P7-22-14-US.DIV.CON, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 16/042,563 is a continuation application of and claims the benefit of U.S. patent application Ser. No. 15/275,078, now Issued U.S. Pat. No. 10,040,329, filed on Sep. 23, 2016, entitled “METHOD AND APPARATUS FOR AN ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-P7-22-14-US.DIV, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 15/275,078 is a divisional application of and claims the benefit of U.S. patent application Ser. No. 14/466,831, now Issued U.S. Pat. No. 9,452,654, filed on Aug. 22, 2014, entitled “METHOD AND APPARATUS FOR AN ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-P7-22-14-US, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 14/466,831 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 14/251,446, filed on Apr. 11, 2014, now Issued U.S. Pat. No. 10,047,817, entitled “METHOD AND APPARATUS FOR ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-P2-11-14-US, and is hereby incorporated by reference in its entirety herein. 
     The U.S. patent application Ser. No. 14/251,446 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 13/934,067, filed on Jul. 2, 2013, now Issued U.S. Pat. No. 10,060,499, entitled “METHOD AND APPARATUS FOR ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-0065US, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/934,067 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 13/843,704, now Issued U.S. Pat. No. 9,033,122, filed on Mar. 15, 2013, entitled “METHOD AND APPARATUS FOR ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-P10-02-12-US, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/843,704, claims the benefit of and claims priority of co-pending U.S. provisional patent application Ser. No. 61/709,041, filed on Oct. 2, 2012, entitled “METHOD AND APPARATUS FOR AN ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-P10-02-12.PRO, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/843,704, claims priority of co-pending U.S. provisional patent application Ser. No. 61/667,327, filed on Jul. 2, 2012, entitled “METHOD AND APPARATUS FOR AN ADJUSTABLE DAMPER” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOXF/0065USL, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 14/251,446 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 13/485,401, now Abandoned, filed on May 31, 2012, entitled “METHODS AND APPARATUS FOR POSITION SENSITIVE SUSPENSION DAMPING” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOXF/0055US, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/485,401 claims the benefit of and claims priority of U.S. provisional patent application Ser. No. 61/491,858, filed on May 31, 2011, entitled “METHODS AND APPARATUS FOR POSITION SENSITIVE SUSPENSION DAMPENING” by Ericksen et al., assigned to the assignee of the present application, having Attorney Docket No. FOXF/0055USL, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/485,401 claims the benefit of and claims priority of U.S. provisional patent application Ser. No. 61/645,465, filed on May 10, 2012, entitled “METHOD AND APPARATUS FOR AN ADJUSTABLE DAMPER” by Cox et al., assigned to the assignee of the present application, having Attorney Docket No. FOX-P5-10-12.PRO, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 14/251,446 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 12/684,072, now Abandoned, filed on Jan. 7, 2010, entitled “REMOTELY OPERATED BYPASS FOR A SUSPENSION DAMPER” by John Marking, assigned to the assignee of the present application, having Attorney Docket No. FOXF/0032US, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 12/684,072 claims the benefit of and claims priority of U.S. provisional patent application Ser. No. 61/143,152, filed on Jan. 7, 2009, entitled “REMOTE BYPASS LOCK-OUT” by John Marking, assigned to the assignee of the present application, having Attorney Docket No. FOXF/0032L, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 14/251,446 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 13/189,216, now Issued U.S. Pat. No. 9,239,090, filed on Jul. 22, 2011, entitled “SUSPENSION DAMPER WITH REMOTELY-OPERABLE VALVE” by John Marking, assigned to the assignee of the present application, having Attorney Docket No. FOXF/0049USP1, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/189,216 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 13/010,697, now Issued U.S. Pat. No. 8,857,580, filed on Jan. 20, 2011, entitled “REMOTELY OPERATED BYPASS FOR A SUSPENSION DAMPER” by John Marking, assigned to the assignee of the present application, having Attorney Docket No. FOXF/0043USP1, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/010,697 claims the benefit of and claims priority of U.S. provisional patent application Ser. No. 61/296,826, filed on Jan. 20, 2010, entitled “BYPASS LOCK-OUT VALVE FOR A SUSPENSION DAMPER” by John Marking, assigned to the assignee of the present application, having Attorney Docket No. FOXF/0043USL, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/189,216 is a continuation-in-part application of and claims the benefit of U.S. patent application Ser. No. 13/175,244, now Issued U.S. Pat. No. 8,627,932, filed on Jul. 1, 2011, entitled “BYPASS FOR A SUSPENSION DAMPER” by John Marking, assigned to the assignee of the present application, having Attorney Docket No. FOXF/0047USP1, and is hereby incorporated by reference in its entirety herein. 
     The application with Ser. No. 13/175,244 claims the benefit of and claims priority of U.S. provisional patent application Ser. No. 61/361,127, filed on Jul. 2, 2010, entitled “BYPASS LOCK-OUT VALVE FOR A SUSPENSION DAMPER” by John Marking, assigned to the assignee of the present application, having Attorney Docket No. FOXF/0047USL, and is hereby incorporated by reference in its entirety herein. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the present technology generally relate to a damper assembly for a vehicle. More specifically, certain embodiments relate to a remotely operated bypass valve used in conjunction with a vehicle damper. 
     BACKGROUND 
     Vehicle suspension systems typically include a spring component or components and a damping component or components. Typically, mechanical springs, like helical springs are used with some type of viscous fluid-based damping mechanism and the two are mounted functionally in parallel. In some instances, features of the damper or spring are user-adjustable. What is needed is an improved method and apparatus for adjusting damping characteristics, including remote adjustment. 
     SUMMARY OF EMBODIMENTS 
     Embodiments include a vehicle suspension damper that comprises: a cylinder and a piston assembly, wherein the piston assembly includes a piston; a working fluid within the cylinder; a bypass cylinder surrounding the cylinder and defining a cylindrical bypass channel; an adjustable bypass port fluidly coupling an interior of the cylinder and the cylindrical bypass channel; and an active bypass valve coupled with the cylindrical bypass channel, the active bypass valve configured to adjust a working size of the adjustable bypass port to modify a flow of said working fluid through the adjustable bypass port. 
     Embodiments also include: active bypass valve for operation within a vehicle suspension damper, the active bypass valve comprising: a threaded plug coupled with an actuator arm, wherein the threaded plug is configured for being angularly displaced within a cylindrical bypass channel about a longitudinal axis of the threaded plug relative to a piston in response to movement of the actuator arm, wherein the cylindrical bypass channel is defined by a bypass cylinder surrounding a cylinder of the vehicle suspension damper; a rod disposed adjacent to the threaded plug, wherein the rod is configured for moving along the longitudinal axis within the cylindrical bypass channel in response to an angular displacement experienced by the threaded plug; and a sleeve disposed adjacent to the rod, wherein the sleeve is configured for moving along the longitudinal axis within the cylindrical bypass channel in response to the moving by the rod, wherein the sleeve provides an adjustment to a flow of a working fluid through an adjustable bypass port fluidly coupling an interior of the cylinder and the cylindrical bypass channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features can be understood in detail, a more particular description may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore into to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
         FIG. 1  is a section view showing a vehicle suspension damper with a bypass, in accordance with an embodiment. 
         FIG. 2A  is an enlarged section view showing an active bypass valve, in accordance with an embodiment. 
         FIG. 2B  is an enlarged section view showing an active bypass valve in a second configuration, in accordance with an embodiment. 
         FIG. 3A  is a section view showing a vehicle suspension damper with an active bypass valve and a reservoir, in accordance with an embodiment. 
         FIG. 3B  is a section view showing a vehicle suspension damper with an active bypass valve having a second configuration and a reservoir, in accordance with an embodiment. 
         FIG. 4  is a schematic diagram showing a control arrangement for a remotely-operated bypass valve, in accordance with an embodiment. 
         FIG. 5  is a schematic diagram of a control system based upon any or all of vehicle speed, damper rod speed, and damper rod position, in accordance with an embodiment. 
         FIG. 6  is an enlarged section view showing an active bypass valve and a plurality of valve operating cylinders in selective communication with an annular piston surface of the valve, in accordance with an embodiment. 
     
    
    
     The drawings referred to in this description should be understood as not being drawn to scale except if specifically noted. 
     DESCRIPTION OF EMBODIMENTS 
     The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. Each embodiment described in this disclosure is provided merely as an example or illustration of the present invention, and should not necessarily be construed as preferred or advantageous over other embodiments. In some instances, well known methods, procedures, objects, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present disclosure. 
     Overview of Discussion 
     Embodiments disclosed herein provide a damping mechanism for a vehicle suspension damper in which a bypass cylinder surrounds a cylinder of the vehicle suspension damper, thereby defining a cylindrical bypass channel. An adjustable bypass port fluidly couples the interior of the cylinder with the cylindrical bypass channel. An active bypass valve functions within the cylindrical bypass channel to meter the flow of working fluid (or damping fluid) from the interior of the cylinder, through the adjustable bypass port leading to the cylindrical bypass channel, and ultimately to a rebound portion of the cylinder. In some embodiments, the active bypass valve operates in conjunction with other damping mechanisms integrated within the vehicle suspension damper. 
     The following discussion will begin with a general description of a vehicle suspension damper, including the active bypass valve, in accordance with an embodiment. (See  FIG. 1 ). The discussion continues with a detailed description of the active bypass valve, in accordance with an embodiment. (See  FIGS. 2-5 ) 
     In the following discussion, the term “active” means adjustable, electronic, manipulatable, etc. while “passive” means fixed or not changeable. Thus, an active valve is a valve which automatically adjusts itself based on characteristics of the vehicle, the suspension, received user input, or the like, in which the valve is used. 
     As used herein, the terms “down”, “up”, “down-ward”, “upward”, “lower”, “upper” and other direction references are relative and are used for reference only. 
     Example Vehicle Suspension Damper with Active Bypass Valve 
       FIG. 1  illustrates a vehicle suspension damper  100  with a live or active bypass valve  102 , in accordance with an embodiment. The vehicle suspension damper  100  includes a cylinder  120  having an interior  124 , a first end  132 , a second end  106  and defining an axis  136 . The vehicle suspension damper  100  further includes a piston rod  142  and a piston  130 . The piston  130  is movably mounted within the cylinder  120  for moving between the first end  132  and the second end  106 . A bypass cylinder  154  surrounds the cylinder  120  and defines a cylindrical bypass channel  156 . The adjustable bypass port  152 , when open, fluidly couples the interior  124  of the cylinder  120  and the cylindrical bypass channel  156 , permitting some working fluid to bypass the vented piston  130  when the piston  130  is positioned on the rebound portion  134  side of the adjustable bypass port  152 . The adjustable bypass port  152 , when partially blocked, fluidly couples the interior  124  of the cylinder  120  and the cylindrical bypass channel  156 , permits less working fluid (e.g., a lesser amount of working fluid than when the adjustable bypass port  152  is fully open) to bypass the vented piston  130  when the piston  130  is positioned on the rebound portion  134  side of the adjustable bypass port  152 . The adjustable bypass port  152 , when completely blocked, fluidly couples the interior  124  of the cylinder  120  and the cylindrical bypass channel  156 , permits no working fluid to bypass the vented piston  130  when the piston  130  is positioned on the rebound portion  134  side of the adjustable bypass port  152 . 
     In one embodiment, the fluid meters from one side of the piston  130  to the other side by passing through flow paths  126 A and  126 B formed in the piston  130 . In the embodiment shown, shims  128 A and  128 B are used to partially obstruct the flow paths  126 A and  126 B in each direction. By selecting shims  128 A and  128 B having certain desired stiffness characteristics, the damping effects caused by the piston  130  can be increased or decreased and damping rates can be different between the compression and rebound strokes of the piston  130 . For example, shims  128 A are configured to meter rebound flow from the rebound portion  134  of the cylinder  120  to the compression portion  104  of the cylinder  120 . Shims  128 B, on the other hand, are configured to meter compression flow from the compression portion  104  of the cylinder  120  to the rebound portion  134 . In one embodiment, shims  128 B are not included on the rebound portion side, nor is there a compression flow path such as flow path  126 B, leaving the piston  130  essentially “locked out” in the compression stroke without some means of flow bypass. Note that piston apertures (not shown) may be included in planes other than those shown (e.g. other than apertures used by flow paths  126 A and  126 B) and further that such apertures may, or may not, be subject to the shims  128 A and  128 B as shown (because for example, the shims  128 A and  128 B may be clover-shaped or have some other non-circular shape). In one embodiment, the piston  130  is solid and all working fluid flow must traverse a flow bypass and/or communicate with a reservoir. 
     The upper portion of the piston rod  142  is supplied with a bushing set  138  for connecting to a portion of a vehicle component such as a wheel suspension linkage. In another embodiment, not shown, the upper portion of the piston rod  142  (opposite the piston  130 ) may be supplied with an eyelet  140  to be mounted to one part of the vehicle, while the lower part of the vehicle suspension damper  100  is attached to another portion of the vehicle, such as the frame, and moves independently of the first part. A spring member (not shown) is usually mounted to act between the same portions of the vehicle as the vehicle suspension damper. As the piston rod  142  and the piston  130  move into the cylinder  120  (during compression), the working fluid slows the movement of the two portions of the vehicle relative to each other due, at least in part, to the incompressible fluid moving through the shimmed flow paths  126 B (past shims  128 B) provided in the piston  130  and/or through an adjustable bypass port  152 , as will be described herein. As the piston rod  142  and the piston  130  move out of the cylinder  120  (during extension or “rebound”), fluid meters again through shimmed flow paths  126 A and the flow rate and corresponding rebound rate is controlled, at least in part, by the shims  128 A. In  FIG. 1 , the piston  130  is shown at full extension and moving downward in a compression stroke, the movement shown by arrow  122 . 
     Example Active Bypass Valve 
       FIG. 2A  is an enlarged view showing the active bypass valve  102 , in accordance with an embodiment. As noted, the adjustable bypass port  152 , when open, fluidly couples the interior  124  of the cylinder  120  with the cylindrical bypass channel  156 , according to an embodiment. The adjustable bypass port  152  permits the working fluid to travel from a first side of the piston  130  to the other side without traversing shimmed flow paths  126 A and  125 B that may otherwise be traversed in a compression stroke of the vehicle suspension damper  100 . In  FIGS. 1 and 2A -B, the adjustable bypass port  152  is shown in an “open” position with the flow of fluid through the bypass shown by arrows  144  from a compression side to a rebound side of the piston  130 . 
     In one embodiment, the entry pathway to the adjustable bypass port  152  in the embodiment shown in  FIGS. 1 and 2A -B is located between the middle and the second end  106  of the cylinder  120 . In one embodiment, as selected by design (e.g., axial location of the entry pathway to the adjustable bypass port  152 ), the adjustable bypass port  152  will not operate after the piston  130  passes the entry to the adjustable bypass port  152  near the end of a compression stroke (or elsewhere in the stroke as desired). In one embodiment, this “position sensitive” feature ensures increased damping will be in effect near the end of the compression stroke to help prevent the piston  130  from approaching a “bottomed out” position (e.g. impact) in the cylinder  120 . The adjustable bypass port  152  and the active bypass valve  102  of the present embodiments can be used in any combination with the bypass valves shown and described in co-pending U.S. patent application Ser. Nos. 13/010,697. 
     The active bypass valve  102 , in accordance with embodiments, includes a threaded plug  150 , a rod  148  and a sleeve  146  disposed within the cylindrical bypass channel  156 . In brief, movement of the actuator arm  158  causes the threaded plug  150  to push the rod  148 . The rod  148  then pushes the sleeve  146 . The sleeve  146  then moves to at least partially cover the adjustable bypass port  152 . 
     More particularly, the actuator arm  158  is operatively connected to the threaded plug  150  such that the threaded plug  150  can be angularly displaced in the direction of arrow  160  about its longitudinal axis  162  relative to the piston  130  in response to operation of the actuator arm  158 . The actuator arm  158  is secured on the threaded plug  150 . The actuator arm  158  extends radially outwardly from the threaded plug  150  such that the threaded plug  150  can be angularly displaced about its longitudinal axis  162  relative to the piston  130  in response to angular displacement of the actuator arm  158  relative to the piston  130 . Of note, depending on the movement of the actuator arm  158 , the sleeve  146  may occupy a position within the cylindrical bypass channel  156  such that the sleeve  146  completely blocks the opening of the adjustable bypass port  152 , partially blocks the opening of the adjustable bypass port  152 , or does not block the opening of the adjustable bypass port  152  at all. 
     In one embodiment, instead of (or in addition to) restricting the working size of adjustable bypass port  152 , active bypass valve  102  can vary a flow rate through an inlet or outlet passage within the active bypass valve  102 , itself. See, as an example, the electronic valve of FIGS. 2-4 of U.S. Pat. No. 9,353,818 which is incorporated by reference herein, in its entirety, as further example of different types of “electronic” or “active” valves). Thus, the active bypass valve  102 , can be used to meter the working fluid flow (e.g., control the rate of working fluid flow) in bypass channel  156  with/or without adjusting the working size (e.g., covering, uncovering, or partially covering the opening) of the adjustable bypass port  152 . 
     For example, active bypass valve  102 , when open, permits a first flow rate of the working fluid to travel through the cylindrical bypass channel  156 . In contrast, when active bypass valve  102  is partially closed, a second flow rate of the working fluid though cylindrical bypass channel  156  occurs. The second flow rate is less than the first flow rate but greater than no flow rate. When active bypass valve  102  is completely closed, the flow rate of the working fluid though cylindrical bypass channel  156  is statistically zero. 
     As can be seen in  FIGS. 1-3B , due to the active bypass valve  102  arrangement, a relatively small solenoid (using relatively low amounts of power) can generate relatively large damping forces. Furthermore, due to incompressible fluid inside the vehicle suspension damper  100 , damping occurs as the adjustable bypass port  152  size is reduced to the movement of sleeve  146 . The result is a controllable damping rate. Certain active valve and bypass features are described and shown in U.S. Pat. Nos. 9,120,362; 8,627,932; 8,857,580; 9,033,122; and 9,239,090 which are incorporated herein, in their entirety, by reference. 
     It should be appreciated that when the actuator arm  158  rotates in a reverse direction than that described above and herein, the threaded plug  150  moves in the direction of the arrow  166 . As the threaded plug  150  moves in the direction of the arrow  166 , the rod  148 , and hence also the sleeve  146 , moves in the direction of the arrow  166 , and the adjustable bypass port  152  is at least partially opened. In one embodiment, upon the movement of the threaded plug  150  in the direction of the arrow  166 , the rod  148  and the sleeve  146  moves in the direction of the arrow  166  due to gravity and/or the force applied by the working fluid against the sleeve  146  from the interior  124  of the cylinder  120  and toward the cylindrical bypass channel  156 . 
     Thus, in addition to the damping features provided by the shims  128 A and  128 B through the flow paths  126 A and  126 B, embodiments enable the metering of working fluid from the interior  124  of the cylinder  120  to the rebound portion  134  of the vehicle suspension damper  100 , via the active bypass valve  102  applied to the adjustable bypass port  152 . 
       FIG. 2B  illustrates a vehicle suspension damper  100  with another embodiment of an active bypass valve  200  which is a different configuration than active bypass valve  102  (as shown in detail in  FIG. 6 ) but which operates in the same overall manner and with the same processes as described with respect to  FIG. 2A , except that the control of the fluid flow is performed through active bypass valve  200  instead of using the sleeve type of configuration of active bypass valve  102 . In  FIG. 2B , active bypass valve  200  extends from suspension damper  100  while the valving portion of active bypass valve  200  remains within the internal bypass configuration of suspension damper  100 . 
       FIG. 3A  illustrates a vehicle suspension damper  100  with an active bypass valve  102  and a reservoir  110 , in accordance with an embodiment. In  FIG. 3A , reservoir  110  is in fluid communication with the cylinder  120  for receiving and supplying working fluid as the piston rod  142  moves in and out of the cylinder  120 . The reservoir  110  includes a reservoir cylinder  116  in fluid communication with the compression portion  104  of the cylinder  120  via the fluid conduit  108 . The reservoir  110  also includes a floating piston  114  with a volume of gas on a backside  118  (“blind end” side) of it, the gas being compressible as the reservoir cylinder  116 , on the “frontside”  112  fills with working fluid due to movement of the piston rod  142  and the piston  130  into the cylinder  120 . Certain features of reservoir type dampers are shown and described in U.S. Pat. No. 7,374,028, which is incorporated herein, in its entirety, by reference. 
     In one embodiment, the active bypass valve  102  is a live valve. That is, one or more of components of active bypass valve  102  (e.g., rod  148 , sleeve  146  or the like) will be actuated automatically based on actual terrain conditions. For example, rod  148  and/or sleeve  146  are controlled by a servo within active bypass valve  102  which will automatically operate rod  148  and/or sleeve  146  to open, close or partially cover the adjustable bypass port  152  with sleeve  146  which will increase or reduce the working size of adjustable bypass port  152  to modify the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134  via the bypass channel  156 . 
     In one embodiment, the live operation includes an active signal received by a receiver at active bypass valve  102  from a computing device. For example, the user would have an app on a smart phone (or other computing device) and would control the settings via the app. Thus, when the user wanted to adjust the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , they would provide the proper command from the computing device and it would be received at active bypass valve  102  which would then automatically operate rod  148  and/or sleeve  146  causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152 . 
       FIG. 3B  illustrates a vehicle suspension damper  100  with another embodiment of an active bypass valve  200 , a reservoir  110 , and an additional active valve  200   b  (which is similar to the active valve  102  and/or  200  as described herein, except that it is provided in fluid conduit  108  instead of in a bypass configuration), in accordance with an embodiment. In  FIG. 3B , reservoir  110  is similar to reservoir  110  of  FIG. 3A , except for the addition of active valve  200   b  in the fluid conduit  108  which can open or close the flow path between the reservoir  110  and the vehicle suspension damper  100  as indicated by flow arrows  244 . 
     In one embodiment, a portion of active bypass valve  200  extends from suspension damper  100  while the valving portion of active bypass valve  200  remains within the internal bypass configuration of suspension damper  100 . 
     Both the active bypass valve  200  and active valve  200   b  are live valves as described in further detail in  FIGS. 4-6 . In one embodiment, active bypass valve  200  will be actuated automatically based on actual terrain conditions. For example, active bypass valve  200  is operated as discussed in  FIGS. 4-6  to open, close or partially allow flow through bypass port  152  to modify the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134  via the bypass channel  156 . 
     In one embodiment, the live operation includes an active signal received by a receiver at active bypass valve  200  and/or active valve  200   b  from a computing system. Thus, to adjust the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , the command would be provided from the computing system and received at active bypass valve  200  which would then automatically open, close or partially allow fluid flow through bypass port  152 . Similarly, the computing system can provide an active signal received by a receiver at active valve  200   b  to adjust the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the reservoir  110 , via the fluid conduit  108 , the would be provided from the computing system and received at active valve  200   b  which would then automatically open, close or partially allow fluid flow through fluid conduit  108 . 
     Although two active valves are shown in  FIG. 3B , it is understood that any number of active valves corresponding to any number of fluid channels (e.g., bypass channels, reservoir channels, bottom out channels, etc.) for a corresponding number of vehicle suspension dampers could be used alone or in combination. That is, one or more active valves could be operated simultaneously or separately depending upon needs in a vehicular suspension system. For example, a suspension damper could have one, a combination of, or each of an active valve(s): for an internal bypass, for an external bypass, for a fluid conduit  108  to the reservoir  110 , etc. In other words, anywhere there is a fluid flow path within a suspension damper  100 , an active valve could be used. Moreover, the active valve could be alone or used in combination with other active valves at other fluid flow paths to automate one or more of the damping performance characteristics of the dampening assembly. Moreover, additional switches could permit individual operation of separate active bypass valves. 
     Referring now to  FIG. 4 , in various embodiments of the present invention, suspension damper includes a bypass channel  156  having an adjustable bypass port  152 , such that the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , is automatically adjustable using active bypass valve  102  to move rod  148  and/or sleeve  146  causing sleeve  146  to change the working size of adjustable bypass port  152 . In one such embodiment, active bypass valve  102  is solenoid operated, hydraulically operated, pneumatically operated, or operated by any other suitable motive mechanism. Active bypass valve  102  may be operated remotely by a switch or potentiometer located in the cockpit of a vehicle or attached to appropriate operational parts of a vehicle for timely activation (e.g. brake pedal) or may be operated in response to input from a microprocessor (e.g. calculating desired settings based on vehicle acceleration sensor data) or any suitable combination of activation means. In like manner, a controller for active bypass valve  102  may be cockpit mounted and may be manually adjustable or microprocessor controlled or both or selectively either. 
     It may be desirable to increase the damping rate or effective stiffness of vehicle suspension damper  100  when moving a vehicle from off-road to on highway use. Off-road use often requires a high degree of compliance to absorb shocks imparted by the widely varying terrain. On highway use, particularly with long wheel travel vehicles, often requires more rigid shock absorption to allow a user to maintain control of a vehicle at higher speeds. This may be especially true during cornering or braking. 
     One embodiment comprises a four-wheeled vehicle having vehicle suspension damper  100  equipped with a bypass channel  156  wherein the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134  via the bypass channel  156  is automatically adjustable using active bypass valve  102  at each (of four) wheel. 
     For example, the opening size of adjustable bypass port  152  which controls the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , is automatically adjusted by active bypass valve  102  (including, for example, a remotely controllable active bypass valve  102 ). In one embodiment, each of the front shock absorbers may be electrically connected with a linear switch (such as that which operates an automotive brake light) that is activated in conjunction with the vehicle brake. When the brake is moved beyond a certain distance, corresponding usually to harder braking and hence potential for vehicle nose dive, the electric switch connects a power supply to a motive force generator for active bypass valve  102  in the front shocks causes active bypass valve  102  to automatically move rod  148  and/or sleeve  146  and cause sleeve  146  to cover or partially cover more of adjustable bypass port  152 . 
     In so doing, the reduction in the size of adjustable bypass port  152  increases the stiffness of that shock. As such, the front shocks become more rigid during hard braking. Other mechanisms may be used to trigger the shocks such as accelerometers (e.g. tri-axial) for sensing pitch and roll of the vehicle and activating, via a microprocessor, the appropriate amount of rotation of active bypass valve  102  to cause sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152  (and corresponding adjustment of the size of adjustable bypass port  152  modifies the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , for the corresponding vehicle suspension damper  100 ) for optimum vehicle control. 
     In one embodiment, a vehicle steering column includes right turn and left turn limit switches such that a hard turn in either direction activates the appropriate adjustment of active bypass valve  102  to cause sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152  (and corresponding adjustment of the size of adjustable bypass port  152  modifies the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , for the corresponding vehicle suspension damper  100 ) of shocks opposite that direction (for example, a hard, right turn would cause more rigid shocks on the vehicle&#39;s left side). Again, accelerometers in conjunction with a microprocessor and a switched power supply may perform the active bypass valve  102  activation function by sensing the actual g-force associated with the turn (or braking; or acceleration for the rear shock activation) and triggering the appropriate amount of rotation of active bypass valve  102  to cause sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152  (and corresponding adjustment of the size of adjustable bypass port  152  modifies the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , for the corresponding vehicle suspension damper  100 ) at a preset acceleration threshold value (e.g., a g-force). 
       FIG. 4  is a schematic diagram showing a control arrangement  400  for a remotely-operated active bypass valve  102 . As illustrated, a signal line  402  runs from a switch  404  to a solenoid  406 . Thereafter, the solenoid  406  converts electrical energy into mechanical movement and shifts position of active bypass valve  102 , thereby adjusting the location of rod  148  and/or sleeve  146  and causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152 . Adjusting the size of adjustable bypass port  152  modifies the flowrate of the fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134 , via the bypass channel  156 , thereby varying the stiffness of a corresponding vehicle suspension damper  100 . 
     As discussed, a remotely-operable active bypass valve  102  like the one described above is particularly useful with an on-/off-road vehicle. These vehicles can have more than 20″ of shock absorber travel to permit them to negotiate rough, uneven terrain at speed with usable shock absorbing function. In off-road applications, compliant dampening is necessary as the vehicle relies on its long travel suspension when encountering often large off-road obstacles. Operating a vehicle with very compliant, long travel suspension on a smooth road at road speeds can be problematic due to the springiness/sponginess of the suspension and corresponding vehicle handling problems associated with that (e.g. turning roll, braking pitch). Such compliance can cause reduced handling characteristics and even loss of control. Such control issues can be pronounced when cornering at high speed as a compliant, long travel vehicle may tend to roll excessively. Similarly, such a vehicle may include excessive pitch and yaw during braking and/or acceleration. With the remotely-operated active bypass valve  102 , the working size of adjustable bypass port  152  is automatically adjusted thereby modifying the communication of fluid between the compression portion  104  of the cylinder  120  and the rebound portion  134  via the bypass channel  156 . Correspondingly, the dampening characteristics of vehicle suspension damper  100  can be changed. 
     In addition to, or in lieu of, the simple, switch-operated remote arrangement of  FIG. 4 , the remotely-operable active bypass valve  102  can be operated automatically based upon one or more driving conditions.  FIG. 5  shows a schematic diagram of a control system  500  based upon any or all of vehicle speed, damper rod speed, and damper rod position. One embodiment of the arrangement of  FIG. 5  is designed to automatically increase dampening in a shock absorber in the event a damper rod reaches a certain velocity in its travel towards the bottom end of a damper at a predetermined speed of the vehicle. In one embodiment, the control system  500  adds dampening (and control) in the event of rapid operation (e.g. high rod velocity) of the vehicle suspension damper  100  to avoid a bottoming out of the damper rod as well as a loss of control that can accompany rapid compression of a shock absorber with a relative long amount of travel. In one embodiment, the control system  500  adds dampening (e.g., adjusts the size of the opening of adjustable bypass port  152  by causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152 ) in the event that the rod velocity in compression is relatively low but the rod progresses past a certain point in the travel. 
     Such configuration aids in stabilizing the vehicle against excessive low-rate suspension movement events such as cornering roll, braking and acceleration yaw and pitch and “g-out.” 
       FIG. 5  illustrates, for example, a control system  500  including three variables: wheel speed, corresponding to the speed of a vehicle component (measured by wheel speed transducer  504 ), piston rod position (measured by piston rod position transducer  506 ), and piston rod velocity (measured by piston rod velocity transducer  508 ). Any or all of the variables shown may be considered by logic unit  502  in controlling the solenoids or other motive sources coupled to active bypass valve  102  for changing the working size of the opening of adjustable bypass port  152  by causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152 . Any other suitable vehicle operation variable may be used in addition to or in lieu of the variables  504 ,  506 , and  508  such as, for example, piston rod compression strain, eyelet strain, vehicle mounted accelerometer (or tilt/inclinometer) data or any other suitable vehicle or component performance data. 
     In one embodiment, the piston&#39;s position within the damping chamber is determined using an accelerometer to sense modal resonance of the suspension damper. Such resonance will change depending on the position of the piston and an on-board processor (computer) is calibrated to correlate resonance with axial position. In one embodiment, a suitable proximity sensor or linear coil transducer or other electro-magnetic transducer is incorporated in the damping chamber to provide a sensor to monitor the position and/or speed of the piston (and suitable magnetic tag) with respect to a housing of the suspension damper. 
     In one embodiment, the magnetic transducer includes a waveguide and a magnet, such as a doughnut (toroidal) magnet that is joined to the cylinder and oriented such that the magnetic field generated by the magnet passes through the rod and the waveguide. Electric pulses are applied to the waveguide from a pulse generator that provides a stream of electric pulses, each of which is also provided to a signal processing circuit for timing purposes. When the electric pulse is applied to the waveguide, a magnetic field is formed surrounding the waveguide. Interaction of this field with the magnetic field from the magnet causes a torsional strain wave pulse to be launched in the waveguide in both directions away from the magnet. A coil assembly and sensing tape is joined to the waveguide. The strain wave causes a dynamic effect in the permeability of the sensing tape which is biased with a permanent magnetic field by the magnet. The dynamic effect in the magnetic field of the coil assembly due to the strain wave pulse, results in an output signal from the coil assembly that is provided to the signal processing circuit along signal lines. 
     By comparing the time of application of a particular electric pulse and a time of return of a sonic torsional strain wave pulse back along the waveguide, the signal processing circuit can calculate a distance of the magnet from the coil assembly or the relative velocity between the waveguide and the magnet. The signal processing circuit provides an output signal, which is digital or analog, proportional to the calculated distance and/or velocity. A transducer-operated arrangement for measuring piston rod speed and velocity is described in U.S. Pat. No. 5,952,823 and that patent is incorporated by reference herein in its entirety. 
     While transducers located at the suspension damper measure piston rod velocity (piston rod velocity transducer  508 ), and piston rod position (piston rod position transducer  506 ), a separate wheel speed transducer  504  for sensing the rotational speed of a wheel about an axle includes housing fixed to the axle and containing therein, for example, two permanent magnets. In one embodiment, the magnets are arranged such that an elongated pole piece commonly abuts first surfaces of each of the magnets, such surfaces being of like polarity. Two inductive coils having flux-conductive cores axially passing therethrough abut each of the magnets on second surfaces thereof, the second surfaces of the magnets again being of like polarity with respect to each other and of opposite polarity with respect to the first surfaces. Wheel speed transducers are described in U.S. Pat. No. 3,986,118 which is incorporated herein by reference in its entirety. 
     In one embodiment, as illustrated in  FIG. 5 , the logic unit  502  with user-definable settings receives inputs from piston rod position transducer  506 , piston rod velocity transducer  508 , as well as wheel speed transducer  504 . Logic unit  502  is user-programmable and, depending on the needs of the operator, logic unit  502  records the variables and, then, if certain criteria are met, logic unit  502  sends its own signal to active bypass valve  102  (e.g., the logic unit  502  is an activation signal provider) to cause active bypass valve  102  to move into the desired state (e.g., adjust the bypass flow rate). Thereafter, the condition, state or position of active bypass valve  102  is relayed back to logic unit  502  via an active bypass valve monitor or the like. 
     In one embodiment, logic unit  502  shown in  FIG. 5  assumes a single active bypass valve  102  corresponding to a single adjustable bypass port  152  of a single vehicle suspension damper  100 , but logic unit  502  is usable with any number of active bypass valves or groups of active bypass valves corresponding to any number of bypass channels, adjustable bypass ports, or groups of bypass channels or adjustable bypass ports. For instance, the suspension dampers on one side of the vehicle can be acted upon while the vehicles other suspension dampers remain unaffected. 
     While the examples illustrated relate to manual operation and automated operation based upon specific parameters, the remotely-operated active bypass valve  102  can be used in a variety of ways with many different driving and road variables. In one example, active bypass valve  102  is controlled based upon vehicle speed in conjunction with the angular location of the vehicle&#39;s steering wheel. In this manner, by sensing the steering wheel turn severity (angle of rotation), additional dampening (by adjusting the corresponding size of the opening of adjustable bypass port  152  by causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152 ) can be applied to one vehicle suspension damper  100  or one set of vehicle suspension dampers on one side of the vehicle (suitable for example to mitigate cornering roll) in the event of a sharp turn at a relatively high speed. 
     In another example, a transducer, such as an accelerometer, measures other aspects of the vehicle&#39;s suspension system, like axle force and/or moments applied to various parts of the vehicle, like steering tie rods, and directs change to position of active bypass valve  102  (and corresponding change to the working size of the opening of adjustable bypass port  152  by causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152 ) in response thereto. In another example, active bypass valve  102  is controlled at least in part by a pressure transducer measuring pressure in a vehicle tire and adding dampening characteristics to some or all of the wheels (by adjusting the working size of the opening of adjustable bypass port  152  by causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152 ) in the event of, for example, an increased or decreased pressure reading. 
     In one embodiment, active bypass valve  102  is controlled in response to braking pressure (as measured, for example, by a brake pedal (or lever) sensor or brake fluid pressure sensor or accelerometer). In still another example, a parameter might include a gyroscopic mechanism that monitors vehicle trajectory and identifies a “spin-out” or other loss of control condition and adds and/or reduces dampening to some or all of the vehicle&#39;s dampers (by adjusting the working size of the opening of adjustable bypass port  152  by causing sleeve  146  to cover, uncover, partially cover, or partially uncover adjustable bypass port  152  chambers) in the event of a loss of control to help the operator of the vehicle to regain control. 
       FIG. 6  is an enlarged view showing an embodiment of a remotely operable active bypass valve  200 . Although  FIG. 6  shows the active bypass valve  200  in a closed position (e.g. during a rebound stroke of the damper), the following discussion also includes the opening of active bypass valve  200 . Active bypass valve  200  includes a valve body  204  housing a movable piston  205  which is sealed within the body. The piston  205  includes a sealed chamber  207  adjacent an annularly-shaped piston surface  206  at a first end thereof. The chamber  207  and piston surface  206  are in fluid communication with a port  225  accessed via opening  226 . Two additional fluid communication points are provided in the body including an inlet  202  and an outlet  203  for fluid passing through the active bypass valve  200 . 
     Extending from a first end of the piston  205  is a shaft  210  having a cone-shaped valve member  212  (other shapes such as spherical or flat, with corresponding seats, will also work suitably well) disposed on an end thereof. The cone-shaped member  212  is telescopically mounted relative to, and movable on, the shaft  210  and is biased toward an extended position due to a spring  215  coaxially mounted on the shaft  210  between the member  212  and the piston  205 . Due to the spring biasing, the cone-shaped member  212  normally seats itself against a seat  217  formed in an interior of the body  204 . 
     As shown, the cone shaped member  212  is seated against seat  217  due to the force of the spring  215  and absent an opposite force from fluid entering the valve along path  156  from the cylindrical bypass channel  156  (of  FIG. 2B ). As member  212  telescopes out, a gap  220  is formed between the end of the shaft  210  and an interior of member  212 . A vent  221  is provided to relieve any pressure formed in the gap. With a fluid path through the active bypass valve  200  (from  203  to  202 ) closed, fluid communication is substantially shut off from the rebound side of the cylinder into the valve body (and hence through the bypass back to the compression side) and its “dead-end” path is shown by arrow  219 . 
     In one embodiment, there is a manual pre-load adjustment on the spring  215  permitting a user to hand-load or un-load the spring using a threaded member  208  that transmits motion of the piston  205  towards and away from the conical member, thereby changing the compression on the spring  215 . 
     Also shown in  FIG. 6  is a plurality of valve operating cylinders  251 ,  252 ,  253 . In one embodiment, the cylinders each include a predetermined volume of fluid  255  that is selectively movable in and out of each cylindrical body through the action of a separate corresponding piston  265  and rod  266  for each cylindrical body. A fluid path  270  runs between each cylinder and port  225  of the valve body where annular piston surface  206  is exposed to the fluid. 
     Because each cylinder has a specific volume of substantially incompressible fluid and because the volume of the sealed chamber  207  adjacent the annular piston surface  206  is known, the fluid contents of each cylinder can be used, individually, sequentially or simultaneously to move the piston a specific distance, thereby effecting the dampening characteristics of the system in a relatively predetermined and precise way. 
     While the cylinders  251 - 253  can be operated in any fashion, in the embodiment shown each piston  265  and rod  266  is individually operated by a solenoid  275  and each solenoid, in turn, is operable from a remote location of the vehicle, like a cab of a motor vehicle or even the handlebar area of a motor or bicycle (not shown). Electrical power to the solenoids  275  is available from an existing power source of a vehicle or is supplied from its own source, such as on-board batteries. Because the cylinders may be operated by battery or other electric power or even manually (e.g. by syringe type plunger), there is no requirement that a so-equipped suspension rely on any pressurized vehicle hydraulic system (e.g. steering, brakes) for operation. Further, because of the fixed volume interaction with the bypass valve there is no issue involved in stepping from hydraulic system pressure to desired suspension bypass operating pressure. 
     In one embodiment, e.g., when active bypass valve  200  is in the damping-open position, fluid flow through the cylindrical bypass channel  156  provides adequate force on the member  212  to urge it backwards, at least partially loading the spring  215  and creating fluid path  201  from the cylindrical bypass channel  156  into a rebound portion  134  of the vehicle suspension damper  100 . 
     The characteristics of the spring  215  are typically chosen to permit active bypass valve  200  (e.g. member  212 ) to open at a predetermined bypass pressure, with a predetermined amount of control pressure applied to inlet  225 , during a compression stroke of vehicle suspension damper  100 . For a given spring  215 , higher control pressure at inlet  225  will result in higher bypass pressure required to open the active bypass valve  200  and correspondingly higher damping resistance in the cylindrical bypass channel  156  (more compression damping due to that bypass). In one embodiment, the control pressure at inlet  225  is raised high enough to effectively “lock” the bypass closed resulting in a substantially rigid compression damper (particularly true when a solid damping piston is also used). 
     In one embodiment, the valve is open in both directions when the valve member  212  is “topped out” against valve body  204 . In another embodiment however, when the valve piston  205  is abutted or “topped out” against valve body  204  the spring  215  and relative dimensions of the active bypass valve  200  still allow for the cone member  212  to engage the valve seat  217  thereby closing the valve. In such embodiment backflow from the rebound side of the cylinder  102  to the compression side is always substantially closed and cracking pressure from flow along path  156  is determined by the pre-compression in the spring  215 . In such embodiment, additional fluid pressure may be added to the inlet through port  225  to increase the cracking pressure for flow along path  156  and thereby increase compression damping through the bypass over that value provided by the spring compression “topped out.” It is generally noteworthy that while the descriptions herein often relate to compression damping bypass and rebound shut off, some or all of the bypass channels (or channel) on a given suspension unit may be configured to allow rebound damping bypass and shut off or impede compression damping bypass. 
     The foregoing Description of Embodiments is not intended to be exhaustive or to limit the embodiments to the precise form described. Instead, example embodiments in this Description of Embodiments have been presented in order to enable persons of skill in the art to make and use embodiments of the described subject matter. Moreover, various embodiments have been described in various combinations. However, any two or more embodiments could be combined. 
     Although some embodiments have been described in a language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed by way of illustration and as example forms of implementing the claims and their equivalents. 
     It should be noted that any of the features disclosed herein may be useful alone or in any suitable combination. While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be implemented without departing from the scope of the invention, and the scope thereof is determined by the claims that follow.