Abstract:
A valve for regulating fluid flow and associated method of use. The valve includes a stepper motor, a first valve portion having an inlet port for receiving fluid into the valve, a second valve portion having an outlet port for dispensing fluid from the valve, a third valve portion located between the first valve portion and the second valve portion, a first member that is rotatable and operatively attached to the stepper motor, and a second member, having a first portion and a second portion, which engages the first member for linear movement of the second member between a first position and a second position when the first member is rotated by the stepper motor to block fluid flow when the second member is located in the first position and allow fluid flow when the second member is located in the second position.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This patent application claims priority to U.S. Provisional Patent Application Ser. No. 60/465,617 filed Apr. 24, 2003. 
     
    
     
       BACKGROUND OF INVENTION  
         [0002]    The current state of the art for controlling the temperature for an engine, e.g., an internal combustion engine, is by using a mechanical wax pellet thermostat to control the flow of coolant to the radiator for a vehicle. This thermostat is a poppet-type of valve that is either fully closed at room temperature or fully open when an engine temperature reaches a predetermined set point.  
           [0003]    There are a number of problems associated with the typical mechanical wax pellet thermostat. Since the temperature-sensing element i.e., wax pellet, must be positioned in the flow stream, there is a very high-pressure drop with associated losses. For engine systems that have relatively large water pumps to provide the necessary coolant flow rates and associated cooling, significant power from the engine must be utilized. This diversion of power affects the performance of the vehicle and wastes fuel.  
           [0004]    Moreover, the fixed-point temperature setting for the engine is primarily determined by the physical composition of the temperature sensing element, i.e., wax pellet. The softening point of any particular wax pellet is fixed and cannot be changed. Therefore, the thermostat is absolutely static with the thermostat either blocking fluid flow or providing maximum fluid flow depending on whether the set temperature is achieved. There is absolutely no dynamic control of engine temperature with a conventional thermostat.  
           [0005]    The present invention is directed to overcoming one or more of the problems set forth above.  
         SUMMARY OF INVENTION  
         [0006]    In one aspect of this invention, a valve for regulating fluid flow is disclosed. This valve includes a stepper motor, a first valve portion that includes an inlet port for receiving fluid into the valve, a second valve portion that includes an outlet port for dispensing fluid from the valve, a third valve portion located between the first valve portion and the second valve portion, a first member that is rotatable and operatively attached to the stepper motor, and a second member, having a first portion and a second portion, that is engageable with the first member for linear movement of the second member between a first position and a second position when the first member is rotated by the stepper motor, wherein the first member and the second member are located within the third valve portion and the first portion of the second member located in the first position can block fluid flow between the first valve portion and the third valve portion and the second portion of the second member located in the second position can allow fluid flow between the first valve portion and the third valve portion.  
           [0007]    In another aspect of this invention, a method for regulating fluid flow with a valve is disclosed. The method includes rotating a first member that is operatively attached to a stepper motor within a valve that includes a first valve portion having an inlet port for receiving fluid into the valve, a second valve portion having an outlet port for dispensing fluid from the valve and a third valve portion located between the first valve portion and the second valve portion, and moving a second member, having a first portion and a second portion, from a first position to a second position through interengagement with the rotating first member, wherein the first portion of the second member located in the first position can block fluid flow between the first valve portion and the third valve portion and the second portion of the second member located in the second position can allow fluid flow between the first valve portion and the third valve portion.  
           [0008]    These are merely some of the innumerable aspects of the present invention and should not be deemed an allinclusive listing of the innumerable aspects associated with the present invention. These and other aspects will become apparent to those skilled in the art in light of the following disclosure and accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0009]    For a better understanding of the present invention, reference may be made to the accompanying drawings in which:  
         [0010]    [0010]FIG. 1 is a top view a stepper motor driven valve in accordance with the present invention;  
         [0011]    [0011]FIG. 2 is a sectional view of the stepper motor driven valve, taken along Line A-A as shown in FIG. 1, in accordance with the present invention in an open position;  
         [0012]    [0012]FIG. 3 is a sectional view of the stepper motor driven valve, taken along Line A-A as shown in FIG. 1, in accordance with the present invention in a closed position;  
         [0013]    [0013]FIG. 4 is a perspective view of the stepper motor driven valve in accordance with the present invention;  
         [0014]    [0014]FIG. 5 is a sectional view of the stepper motor driven valve, taken along Line B-B in FIG. 3, in accordance with the present invention;  
         [0015]    [0015]FIG. 6 is an exploded view of the stepper motor driven valve in accordance with the present invention;  
         [0016]    [0016]FIG. 7 is a basic schematic of a fluid, e.g., coolant, system for a vehicle that illustrates an engine, a radiator, a pump, and a bypass loop where fluid, e.g., coolant, flow through the bypass loop is controlled by the valve of the present invention; and  
         [0017]    [0017]FIG. 8 is a basic schematic of a fluid, e.g., coolant, system for a vehicle that illustrates an engine, a radiator, a pump, a thermostat and a bypass loop where fluid, e.g., coolant, flow through the bypass loop is controlled by the valve of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0018]    In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as to obscure the present invention. For example, the invention can be applied to virtually any type of device that can benefit from controlled fluid flow. Moreover, this invention can be applied to virtually any type of application that utilizes fluid as a coolant for reducing heat. Although the preferred application involves the thermal management of an engine, e.g., an internal combustion engine, a wide variety of applications that can benefit from thermal management brought about by fluid flow, throughout a range, will be applicable and not necessarily those applications related to motorized vehicles. The fluid is preferably coolant; however, a wide range of fluids may suffice.  
         [0019]    Referring now to the drawings, and initially to FIGS. 1, 2,  3  and  6 , where a valve that is utilized to control fluid, e.g., coolant, flow to provide thermal management is generally indicated by numeral  2 . The valve  2  is shown in a default or unpowered position in FIG. 2. There is a biasing mechanism  4 , which is preferably, but not necessarily, in the form of a return spring. The biasing mechanism  4  applies a load to a plunger  6 . This plunger  6  is preferably aligned with a vertical axis or centerline  3  for the valve  2  in the illustrative, but nonlimiting, embodiment. However, this is not a necessity.  
         [0020]    The plunger  6  preferably includes a first portion  9  and a second portion  11 . The first portion  9  can include a wide variety of geometric shapes and configurations. Preferably, but not necessarily, the first portion  9  is cylindrical or at the very least a portion of the lower portion  9  is cylindrical. Preferably, there is at least one protrusion on the outer circumference of the lower portion  9  and optimally, there is first, upper protrusion  66 , a second, middle protrusion  67  and a third, lower protrusion  68 . Preferably, the plunger  6 , having a longitudinal axis, includes at least one fluid passage  135 , e.g., four (4) fluid passages, that is preferably parallel to the longitudinal axis of the plunger as shown in FIG. 5.  
         [0021]    The second portion  11  of the plunger  6  preferably, but not necessarily, includes a series of triangular support portions  71 ,  72 ,  73  and  74 , as best shown in FIG. 5. The triangular support portions  71 ,  72 ,  73  and  74 , each preferably include a slot  77 ,  78 ,  79  and  80 , respectively, that supports the bottom portion of the biasing mechanism, e.g., return spring  4 .  
         [0022]    As shown in FIGS. 2 and 3, there are a plurality of female threads or a plurality of female indentations  8  (collectively can be referenced as “indentations”) that are integrally formed and located therein that are capable of mating with a plurality of male protrusions or a plurality of male threads  10  (collectively can be referenced as “protrusions”) in a screw  12 . Due to the force of the biasing mechanism, e.g., return spring  4 , there are both translational and rotational loads applied to the plunger  6 .  
         [0023]    Therefore, when the screw  12  rotates, the plurality of male protrusions or threads  10  engage the plurality of the female threads or indentations  8  in the plunger  6  so that the plunger  6  can move up or down along the vertical axis or centerline  3  depending on the direction of rotation of the screw  12 . The screw  12  is operatively connected to a stepper motor  16 . Preferably, the screw  12  is mechanically connected with hardware to the stepper motor  16 ; however, attachment by adhesives, thermal bonding and other methods will suffice. The preferred hardware is a connecting sleeve portion  18 , which is preferably, but not necessarily, part of the screw  12 , which connects to the rotor  20  for the stepper motor  16 , as shown in FIGS. 2, 3 and  6 . An illustrative, but nonlimiting, example of a stepper motor  16  includes SKC Motor Number XE-2002-0962-00 manufactured by Shinano Kenshi Corp., having a place of business at 5737 Mesmer Avenue, Culver City, Calif. 90230. However, a wide variety of stepper motors  16  will suffice for the present invention.  
         [0024]    A wide variety of materials can be utilized for the main components of the valve  2  with the exception of the stepper motor  16  and fluid sealing mechanisms. One illustrative, but nonlimiting, example includes 1503-2 grade of resin that includes nylon 6/6 that is glass reinforced and manufactured by TICONA®, having a place of business at 90 Morris Avenue, Summit, N.J. 07901. However, a wide variety of other materials will suffice for this application. One illustrative, but nonlimiting, example of material for the plunger  6  includes an acetal copolymer. An acetal copolymer is a polyoxymethylene (POM) with a high crystallinity delivering high strength, stiffness, toughness, and lubricity over a broad range of temperatures and chemical environments. An acetal copolymer can be processed by many conventional means including injection molding, blow molding, extrusion and rotational casting. One illustrative, but nonlimiting, example of material for the screw  12  includes nylon 6 combined with polytetrafluoroethylene (PTFE) to reduce friction.  
         [0025]    A feature of this valve  2  is the force balance between the stepper motor  16  and the biasing mechanism, e.g., return spring  4 . This valve  2  is designed so that when an appropriate signal is provided to the stepper motor  16 , there is sufficient force to turn the screw  12  that moves the plunger  6  to compress the biasing mechanism, e.g., return spring  4 , and close the valve  2 . The construction and design of the biasing mechanism, e.g., return spring  4 , can vary greatly to comport with the wide variety of stepper motors utilized to create to balance the force. Conversely, there must be enough force in the biasing mechanism, e.g., return spring  4 , to turn the screw  12  to move the plunger  6  that rotates the stepper motor  16  when power is removed from the stepper motor  16  so that the valve  2  can be opened. Therefore, a feature of this invention is the ability for the valve  2  to go to a full open position as a failsafe when power is removed from the stepper motor  16 .  
         [0026]    As shown in FIGS. 1-4 and as best shown in FIG. 6, the stepper motor  16  includes a protective outer housing end cap  26  that covers the outer top portion of the stepper motor  16 . As shown in FIG. 6, there is a gasket  27  having an electrical terminal connector  28  to provide electrical connections to the terminals (not shown) on the stepper motor  16 . This electrical terminal connector  28  provides a simple electrical interface that can be easily connected to other components in an electrical system.  
         [0027]    As shown in FIGS. 2, 3,  5  and  6 , located below the stepper motor  16  is a valve body  32 . There is a cover member  30  that preferably, but not necessarily, includes a support portion and preferably an upper motor support portion  83  and a lower portion  84 . Preferably, but not necessarily, both an upper motor support portion  83  and a lower portion  84  are cylindrical depending on the geometric shape of the stepper motor  16 . Extending outward from between the upper motor support portion  83  and the lower portion  84  is at least one sealing portion that preferably includes a first outer member  85  and a second outer member  86 . The first outer member  85  and the second outer member  86  operate to seal the cover member  30  to the valve body  32 , as shown in FIGS. 1, 4,  5  and  6 .  
         [0028]    The upper motor support portion  83 , the lower portion  84 , the first outer member  85  and the second outer member  86  may all be part of an integral cover member  30  or each may be separate parts connected together and any combination thereof. Preferably, the cover member  30  is mechanically connected with hardware to the valve body  32 ; however, attachment by adhesives, thermal bonding and other methods will suffice. Preferably, a first bolt  63  and a second bolt  64  are utilized to secure the first outer member  85  and the second outer member  86 , respectively to the valve body  32 .  
         [0029]    As shown in FIGS. 2, 3 and  5 , the lower portion  84  includes an outer flange  117  and at least one protruding member  119  located within the outer flange  117 . There is preferably a pair of retaining guide members  121  and  123  located on the second portion  11  of the plunger  6 , as shown in FIG. 5. This provides an anti-rotational feature so that the plunger  6  only translates force along the centerline  3  of the valve  2 .  
         [0030]    Preferably, but not necessarily, located near a bottom portion of the outer surface of the outer flange  117  is at least one protrusion  92  that forms at least one u-shaped channel  94 , which is followed by an extending lip portion  96 , as shown in FIG. 6.  
         [0031]    There is a radial seal  42  located on the inside of the valve body  32 . The radial seal  42  may include a wide variety of geometric shapes and configurations; however, the preferred embodiment includes at least one rectangular portion  102  and at least one c-shaped portion  104 . The rectangular portion  102  is preferably located within the u-shaped channel  94  in the outer flange  117  and the c-shaped portion  104  is preferably positioned adjacent to the extending lip portion  96 . A seal made of polytetrafluoroethylene (PTFE) or a lip seal may also be utilized. The radial seal  42  keeps the load low that is due to the differential pressure.  
         [0032]    There is a first o-ring  38  located between the cover member  30  and the connecting sleeve portion  18  of the screw  12  and the stepper motor  16 . There is also a second o-ring  40  located between the biasing member, e.g., return spring  4 , and the plunger  6 . An illustrative, but nonlimiting material can include a Nitrile/Buna-N type of material as well as EPDM at higher temperatures. An illustrative, but nonlimiting, manufacturer can include Quality Synthetic Rubber, Inc. (QSR), having a place of business at 1700 Highland Road, Twinsburg, Ohio 44087.  
         [0033]    The valve body  32  includes an inlet port  46  for receiving fluid and an outlet port  48  for releasing fluid. There is a third valve portion  50  where the plunger  6  moves up and down that is located between a first valve portion  54  and a second valve portion  56 .  
         [0034]    The first valve portion  54  receives fluid, e.g., coolant, into the valve  2  and includes the inlet port  46 . The second valve portion  56  transmits fluid, e.g., coolant, from the valve  2  and includes the outlet port  48 .  
         [0035]    As shown in FIG. 3, when the valve  2  is closed, the plunger  6  is positioned as close to the stepper motor  16  as possible in a first position and the plunger completely blocks the flow of fluid, e.g., coolant, in the third valve portion  50  so that the fluid, e.g., coolant, flowing into the inlet port  46 , through the first valve portion  54  is blocked by the first portion  9  of the plunger  6  so that fluid, e.g., coolant, cannot go into the second valve portion  56  that is in fluid communication with the outlet port  48  and the fluid, e.g., coolant, does not have any access to the fluid passage  135 .  
         [0036]    As shown in FIG. 2, when the valve  2  is open, the plunger  6  is positioned on the bottom of the valve body  32  in a second position and as far away from the stepper motor  16  as possible. This allows fluid, e.g., coolant, to flow between the inlet port  46 , through the first valve portion  54 , and then into the third valve portion  50  through the fluid passage  135  in the plunger  6 . Fluid, e.g., coolant, then flows out through the second valve portion  56  and then the outlet port  48 . Therefore, the present invention includes a first position where the valve is fully closed and a second position where the valve is fully open. However, it is only this specific illustrative embodiment where the position of the plunger  6  to the stepper motor  16  has any relevance to these two positions and with slight modifications to the valve  2  the relationship of the position of the plunger  6  to the stepper motor  16  and these two positions can be reversed.  
         [0037]    Due to the radial seal  42 , any high pressure differential pressure across the valve  2  between the first valve portion  54  and the second valve portion  56  has a negligible effect on the pressure balance on the plunger  6  caused by the stepper motor  16  and the biasing mechanism, return spring  4 . Therefore, the pressure drop across the valve  2  is relatively low due to the radial seal  42 .  
         [0038]    Under normal operating conditions, the stepper motor  16  will be powered to rotate the screw  12  in either a clockwise or counterclockwise direction to move the plunger  6  either up or down. There are two operating conditions. The first condition is the full opening region. The full opening region is from when the plunger  6  is as far as possible to the stepper motor  16  to being extended to the point where the plunger  6  is in contact with the bottom of the valve body  32  to allow full fluid flow. The second operating condition is when the valve is in a fully closed position. This is when the plunger  6  is as close as possible to the stepper motor  16  and the plunger  6  is in contact with the radial seal  42 . Between the first operating condition and the second operating condition, the valve  2  controls the fluid flow in a step-wise linear manner, which can be dynamically altered based on operating conditions to provide a fully variable fluid flow.  
         [0039]    The degrees of rotation for the stepper motor  16  can range from about zero (0) degrees per step to about one hundred and eighty (180) degrees per step and preferably from about twenty (20) degrees per step to about fifty (50) degrees per step and optimally about 1.8 degrees per step. The pitch of the screw  12  can range from about two (2) male protrusions or threads  10  per inch to about fifty (50) male protrusions or threads  10  per inch and preferably from about three (3) male protrusions or threads  10  per inch to about eight (8) male protrusions or threads  10  per inch and optimally about five (5) male protrusions or threads  10  per inch. Therefore, the plunger  6  can travel from about 10 inches per step to about 0.000001 inches per step and preferably from about 0.01 inches per step to about 0.001 inches per step and optimally about 0.001 inches per step. As an illustrative example, at 1.8 degrees per step with the pitch of the screw  12  at five (5) male protrusions or threads  10  per inch and the plunger  6  traveling 0.001 inches per step, results in 500 steps for the plunger  6  to travel one (0.5) inch for very precise flow control.  
         [0040]    Referring now to FIG. 7, as one illustrative, but nonlimiting application, the valve  2  can be utilized to provide fluid, e.g., coolant, flow from an engine  127  through a first fluid conduit  137  and into either the valve  2  or a bypass loop  133 . The valve  2  controls the flow of fluid, e.g., coolant, into a radiator  131  via a third fluid conduit  139 . The fluid, e.g., coolant, then goes into a fluid pump  129  from the radiator  131  via a fourth fluid conduit  141  and the bypass loop  133  and then back into the engine  127  via a second fluid conduit  143 . By diverting more fluid, e.g., coolant, into the bypass loop  133  rather than the radiator  131 , the engine  127  can run hotter with greater fuel efficiency and reduced emissions. The valve  2  can be operated from sensor data from a processor (not shown) to maximize performance of the engine  127 . Preferably look-up tables can be utilized in conjunction with the sensor data. This will control the temperature of the engine  127  through a complete range of fluid flow rather than a thermostat being merely off or turned on. The previously mentioned failsafe feature of the valve  2  is important so that fluid, e.g., coolant, can always be provided to the radiator  131  to prevent damage to the engine  127 .  
         [0041]    Referring now to FIG. 8, as another illustrative, but non-limting application, the valve  2  can be utilized to control fluid, e.g., coolant, flow through the bypass loop  133  from the engine  127  from a first fluid conduit  137 . The standard thermostat  125  has not reached the set point, all flow of fluid, e.g., coolant, from the fluid pump  129  through a second fluid conduit  143  and into the engine  127  and then into the bypass loop  133  via the first fluid conduit  137  and then back into the fluid pump  129 . By controlling the amount of fluid flow in the bypass loop  133 , the engine  127  can run hotter with greater fuel efficiency and reduced emissions. The valve  2  can be operated from sensor data from a processor (not shown) to maximize performance of the engine  127 . Preferably, look-up tables can be utilized in conjunction with the sensor data. This will control the temperature of the engine  127  through a complete range of fluid flow until the set point of the thermostat  125  is reached. At this point, the valve  2  can be operated in conjunction with the thermostat  125  to accurately control the temperature of the engine  127  with fluid going through the thermostat  125  via the first fluid conduit  137  and into a radiator  131  via a third fluid conduit  139 . From the radiator  131  fluid goes back into the inlet for the fluid pump  129  via a fourth conduit  141 .  
         [0042]    Although the preferred embodiment of the present invention and the method of using the same has been described in the foregoing specification with considerable details, it is to be understood that modifications may be made to the invention which do not exceed the scope of the appended claims and modified forms of the present invention done by others skilled in the art to which the invention pertains will be considered infringements of this invention when those modified forms fall within the claimed scope of this invention.