Abstract:
An actuator control system including a servo-actuator comprising: at least one coil; a solenoid core within the at least one coil; a rod within the solenoid core having a first end, a second end, and a length extending between the first end and the second end, the first end coupled to a sensing core pin having a profile; a moveable member coupled to the second end of the rod; a moveable armature within the solenoid core surrounding a portion of the length of the rod and biased by a spring; and a noncontact sensor integral with servo-actuator and aligned with the first end of the rod coupled to the sensing core pin. A selected position of the servo-valve actuator may be set by the ECU by sensing the position of the sensing core pin using the non-contact sensor.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims one or more inventions which were disclosed in Provisional Application No. 61/053,715, filed May 16, 2008, entitled “INTEGRATED SENSOR FOR POSITION CONTROL” and Provisional Application No. 61/056,209, filed May 27, 2008, entitled “INTEGRATED SENSOR FOR POSITION CONTROL”. The benefit under 35 USC §119(e) of the United States provisional applications are hereby claimed, and the aforementioned applications are hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to the field of actuator control valve systems. More particularly, the invention pertains to an integrated sensor for position control in an actuator control valve system. 
     2. Description of Related Art 
     Prior art servo actuation systems require that a sensor be mounted separately from the servo control valve, creating additional leak paths and complexity to the assembly. In addition, because the sensors are mounted in different locations, they are not directly coupled to the moving member of the system, reducing the accuracy of the servo actuation systems. 
     The present invention integrates the sensor into the assembly, reducing the costs, eliminating the additional leak paths, and providing more accurate position sensing of the moving member directly. 
     SUMMARY OF THE INVENTION 
     An actuator control system including a servo-actuator comprising: at least one coil; a solenoid core within the at least one coil; a rod within the solenoid core having a first end, a second end, and a length extending between the first end and the second end, the first end coupled to a sensing core pin having a profile; a moveable member coupled to the second end of the rod; a moveable armature within the solenoid core surrounding a portion of the length of the rod and biased by a spring; and a noncontact sensor integral with servo-actuator and aligned with the first end of the rod coupled to the sensing core pin. A selected position of the servo-valve actuator may be set by the ECU by sensing the position of the sensing core pin using the non-contact sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a view of an actuator control valve system in a first embodiment of the present invention. 
         FIG. 2  shows an alternate view of the actuator control valve system shown in  FIG. 1 . 
         FIG. 3  shows another view of the actuator control valve system shown in  FIG. 1 . 
         FIG. 4  shows a cross-section of the actuator control valve system shown in  FIG. 1 . 
         FIG. 5  shows a view of an actuator control valve system in a second embodiment of the present invention. 
         FIG. 6  shows a cross-section of the actuator control valve system shown in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1-4  show an actuator control valve system in a first embodiment of the present invention. The actuator valve control system  10  includes a servo-actuator  12  with a servo-valve body  16  and an integrated sensor  14 . 
     The servo-actuator  12  includes a servo-valve body  16  and a solenoid core  33  surrounded by coil(s)  38 . The solenoid core  33  includes a null spring  34  and a spring retainer  35 , an adjustable spring retainer  80  and a movable armature  32 . An air gap  41  is present between the armature  32  and the solenoid core  33 . The servo-actuator  12  also has a sensing rod  30  with a first rod end  30   a  with a sensing core pin  36  and a second rod end  30   b  connectable to a movable member  18 . The sensing core pin  36  is sensed by a non-contact sensor  14  built into or integral with an end of the servo-actuator  12 . The non-contact sensor  14  reports the position of the sensing core pin  36  to the ECU or ECM (not shown) in unison and proportional with the movement of moveable member  18 . A push rod guide  31  with a flange  31   a  is mounted to the armature  32  and is mounted over the sensing rod  30  along its length between the first rod end  30   a  and the second rod end  30   b . The flange  31   a  of the guide  31  on the sensing rod  30  is present in the air gap  41  between the solenoid core  33  and the movable armature  32 . The sensing rod  30  passes through the solenoid core  33  of the servo-valve  12 , the armature  32  within the solenoid core  33 , the guide  31  with a flange  31   a  and the solenoid core  33 , the feedback spring  37 , the null spring  34 , the spool  17  and the servo-valve body  16 . An adjustable spring retainer  80  at one end of the null spring  34  maintains the null spring  34  within the solenoid core  33 , and spring retainer  35  at the opposite end of the null spring  34  contacts the guide  31 , allowing the sensing rod  30  to move freely and independently of the armature  32 , push rod guide  31 , null spring  34 , spring  37  and spool  17  housed in servo-valve body  16 . 
     The actuation of the armature  32  occurs via an increasing electrical signal to the coil(s)  38  from the ECU, which increases the magnetic force in gap  41  proportional to the increasing electrical signal to coil(s)  38 . The armature  32 , push rod guide  31 , spool  17  housed in servo-valve body  16  moves in a first direction decreasing gap  41  between the solenoid core  33  and the movable armature  32  and compresses null spring  34  and extends spring  37 . Pressurized fluid is communicated to one side of the piston rack assembly  28  and drained from an opposing side of piston rack assembly  28  via spool  17  in conjunction with servo-valve body  16  through appropriate passage(s) in the servo-actuator  10 . The movement of the fluid causes the piston-rack assembly  28  to move in a first direction and the teeth  22  on the pinion  20  and the teeth  26  on the rack  24  mesh as shown in  FIG. 3 , thereby causing the cam profile of pinion  20  in this example to move or rotate in a first direction, allowing moveable member  18  to move away from spool  17  along its axis, altering the force balance between spring  34  and spring  37 . The force balance between spring  34  and spring  37  changes until the spring force balance equals the magnetic force generated in gap  41  between the solenoid core  33  and armature  32  as generated by the electrical commanded signal from the ECU to coil(s)  38 . 
     As motion of the moveable member  18  continues in the first direction, armature  32 , push rod guide  31 , and the spool  17  housed in servo-valve body  16  also move. The spool  17  blocks fluid from entering and draining the appropriate passages to and from piston rack assembly  28 . Since sensing rod  30  is attached to and or mounted against movable member  18  at the second rod end  30   b , the sensing rod  30  follows moveable member  18  as it moves along its axis, thereby changing the position of the sensing core pin  36  in reference to the non contact sensor  14 . 
     The change in position in a first direction is communicated to and monitored by the ECU or ECM. The sensor  14  provides electric feedback to the ECU or ECM, as well as on board diagnostic capabilities. Based on the information from the sensor, the ECU or ECM can map the performance of the actuator control valve system to establish an initial performance mapping as well as monitor the performance throughout the life expectancy of the system. 
     Upon de-actuation of the armature  32  via a decreasing electrical signal to the coil(s)  38 , the magnetic force in gap  41  proportional to the decreasing electrical signal to coil(s)  38  is reduced. The armature  32 , guide  31 , spool  17  housed in servo-valve body  16  moves in a second direction increasing the gap  41  between the solenoid core  33  and the armature  32  and de-compresses spring  34  and compresses spring  37 . Pressurized fluid is communicated to one side of the piston rack assembly  28  and drained from the opposing side of piston rack assembly  28  via spool  17  and servo-valve body  16  through appropriate passage(s) in servo-actuator  10 . The movement of fluid causes the piston-rack assembly  28  to move in a second direction and the teeth  22  on the pinion  20  and the teeth  26  on the rack  24  mesh as shown in  FIG. 3 , thereby causing the cam profile of pinion  20  in this example to move/rotate in a second direction allowing moveable member  18  to move towards the spool  17  along its axis, compresses spring  37  and increasing the opposing force of spring  37  to null spring  34 . The force balance between spring  34  and spring  37  changes until the spring force equals the magnetic force generated in gap  41  between solenoid core  33  and armature  32  proportional to the electrical commanded signal to the coil(s)  38 . 
     As motion of the moveable member  18  continues in a second direction, the armature  32 , guide  31 , and spool  17  move. The spool  17  blocks fluid from entering and draining the appropriate passages in actuator  10  to piston rack assembly  28 . Since sensing rod  30  is attached to and or mounted to member  18  at the second rod end  30   b , the sensing rod  30  follows moveable member  18  as it moves along its axis, thereby changing the position of the sensing core pin  36  in reference to the non contact sensor  14  in the second direction. The change in position in a second direction is monitored by the ECU or ECM. 
     The sensor  14  provides electric feedback to the ECU or ECM, as well as on board diagnostic capabilities. Based on the information from the sensor, the ECU or ECM can map the performance of the actuator control valve system to establish an initial performance mapping as well as monitor the performance throughout the life expectancy of the system. 
     It should be noted that the positional control of the servo-valve actuator is infinite between the first direction and the second direction proportional to the applied input electrical signal to coil(s)  38 . Hence, sensor  14  provides infinite positional feed back to the ECU or ECM of the actuation system. 
     If the non-contact sensor  14  were to fail, open loop control may be still be obtained by the position feed back spring  37  between spool  17  and the external member  18 . 
     The sensor core  33  profile may be straight, tapered hollow like a tube, concave, convex, profiled-contoured, or parabolic to achieve optimum linearity of the output signal versus position. 
     The sensor  14  may be added to any mechanical feedback valve within the actuator control valve systems such as a hydraulic, a pneumatic, a rotary or a linear actuated control valve system. The actuator system may be directly or pilot operated by either electrical, hydraulic, pneumatic, or other mechanical means. The actuator control valve system may be part of an but not limited to an EGR system, waste gate control system, cooler bi-pass control system, turbo bi-pass control system, pneumatic flow divider, hydraulic flow divider, variable geometry turbo charger control system, coolant control system, fuel control systems, or cam phasing systems in a combustion or fuel cell engine control management system. 
     The sensor  14  may be, but is not limited to, an eddy current type, single coil inductive as shown, a LVDT sensor, a Hall Effect sensor, a magnetostrictive position sensor, or a potentiometer. 
       FIGS. 5-6  show an actuator control valve system in a second embodiment of the present invention. The actuator valve control system  50  includes a servo-actuator  51  with a servo-valve  16  and an integrated sensor  14 . 
     The servo-actuator  51  includes a solenoid core  33  surrounded by coil(s)  38 . The solenoid core  33  includes a first spring  64  and a movable armature  32  at one end and a bearing-passage portion  33   a  at an opposite end. An air gap  41  is present between the armature  32  and the solenoid core  33 . The servo-actuator  51  also has a sensing rod  30  with a first rod end  30   a  with a sensing core pin  36  and a second rod end  30   b  connectable to a moveable member  58 . The sensing core pin  36  is sensed by a non-contact sensor  14  built into or integral with an end of the servo-actuator  51 . The non-contact sensor  14  reports the position of the sensing core pin  36  to the ECU or ECM (not shown). 
     A guide  31  with a flange  31   a  is mounted to the armature  32  which is mounted over sensing rod  30  along its length between the first rod end  30   a  and the second rod end  30   b . The flange  31   a  of the push rod guide  31  mounted over the sensing rod  30  is present between the armature  32  and the bearing passage portion  33   a  of the solenoid core  33 . The sensing rod  30  passes through the solenoid core  33  of the servo-valve  12 , the armature  32  within the solenoid core  33 , the guide  31  with a flange  31   a  present within the bearing passage portion  33   a  of the solenoid core  33 , the first spring  64  and a second spring  67  mounted between a moveable member  58  and the spool  17  of the servo-valve  16 . A spring retainer  35  at one end of the spring  64  maintains the first spring  64  within the solenoid core  33  between the end of the solenoid core  33  and the armature  32 . 
     The servo-valve  16  includes a servo-valve actuator housing assembly  57  with a spool  17 , and a second spring  67 , with one end mounted to the spool  17  and an opposite end mounted to a moveable member  58 . The spool  17  is biased in an opposite direction by a first spring  64  through the armature  32  and push rod  31 . Attached to the moveable member  58  is a piston  53  within a chamber  52  and  61  between moveable member  58  and the servo-valve actuator housing  57 . The spool  17  housed in the servo-valve body  16  directs fluid to and from passages in the servo-valve housing  57  to the chambers  52  and  61  formed between the piston  53  and the servo-valve housing  57 . 
     The actuation of the armature  32  via an increasing electrical signal to coil(s)  38 , increases the magnetic force in the gap  41  between armature  32  and solenoid core  33  proportional to the increasing electrical signal to coil(s)  38  and compresses spring  67  and extends spring  64 . Pressurized fluid is communicated to one side of the piston  53  via spool  17  through appropriate passages  59 ,  70 ,  54  in the servo-actuator housing  57  to chamber  52  and fluid is drained from chamber  61  in servo-actuator assembly  57  through passages  62 ,  66 ,  63  formed by spool  17 . The movement of fluid causes the piston assembly of piston  53  and moveable member  58  to move in a first direction, compressing spring  67  and increasing the opposing force to spring  64  and magnetic force in gap  41  generated by the electrical signal to coil(s)  38  between solenoid core  33  and armature  32 . As the piston assembly moves, the force of spring  67  increases, the spool  17 , push rod  31 , and armature  32  moves inside servo-valve body  16  and solenoid core  33  until fluid is blocked from entering chamber  52  and draining from chamber  67  by the spool  17 . As the piston  53  and moveable member  58  moves, sensor rod  30  follows and the sensor core pin  36  at a first rod end  30   a  changes position in reference to non contact sensor  14  to reflect the position of the piston  53  and piston member  58 . 
     Upon de-actuation of the armature  32  via a decreasing electrical signal to coil(s)  38 , the magnetic force in gap  41  between the armature  32  and the solenoid core  33  decreases proportional to the decreasing electrical signal to coil(s)  38  and compresses spring  64  and extends spring  67 . Pressurized fluid is communicated to one side of the piston  53  via spool  17  through appropriate passages  59 ,  65 ,  62  in the servo-actuator housing  57  and the spool  17  to chamber  61  and drains fluid from chamber  52  in servo-actuator assembly  57  through passages  54 ,  70 , and  63 , causing the piston assembly of the piston  53  and moveable member  58  to move in a second direction. As the piston assembly moves and decreases the opposing force of spring  67 , the spool  17 , push rod  31 , and armature  32  moves inside servo-valve body  16  and solenoid core  33  until fluid is blocked from entering chamber  61  and exiting chamber  52  by the spool  17 . As the piston assembly of piston  53  and moveable member  58  moves, sensing rod  30  follows and the sensor core pin  36  at the first rod end  30   a  changes position in reference to the non contact sensor  14  to reflect the position of the piston  53  and moveable member  58 . 
     The sensor  14  provides electric feedback to the ECU or ECM, as well as on board diagnostic capabilities. Based on the information from the sensor, the ECU or ECM can map the performance of the actuator control valve system to establish an initial performance mapping as well as monitor the performance throughout the life expectancy of the system. 
     The sensor core  33  profile may straight, tapered, concave, hollow like tube, convex, profiled-contoured, or parabolic to achieve optimum linearity of the output signal versus position. 
     The sensor  14  may be added to any mechanical feedback valve within the actuator control valve systems such as a hydraulic, a pneumatic, a rotary or a linear actuated control valve system. The actuator system may be directly or pilot operated by either electrical, hydraulic, pneumatic, or other mechanical means. The actuator control valve system may be part of, but not limited to an EGR system, waste gate control system, cooler bi-pass control system, turbo bi-pass control system, pneumatic flow divider, hydraulic flow divider, variable geometry turbo charger control system, coolant control system, fuel control systems, or cam phasing systems in a combustion or fuel cell engine control management system. 
     The sensor  14  may be, but is not limited to, an eddy current type, single coil inductive as shown, a LVDT sensor, a Hall Effect sensor, magnetostrictive position sensor or a potentiometer. 
     It should be noted that the positional control of the servo-valve actuator is infinite between the first direction and the second direction proportional to the applied input electrical signal to coil(s)  38 . Hence, sensor  14  provides infinite positional feed back to the ECU or ECM of the actuation system. 
     Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.