Abstract:
An electronic coolant valve with a flexible sealing membrane. The membrane is expanded or contracted radially via a drive screw and an electric motor. The extension and retraction of the drive screw changes the shape of the membrane in the flow passage. The membrane can be adjusted to allow full passage of coolant through a passageway, to completely block off (close) the flow channel preventing fluid from flowing through it, or to allow a restricted or metered amount of coolant to pass through the passageway.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Application Ser. No. 61/378,912, filed on Aug. 31, 2010. 
     TECHNICAL FIELD 
     The present invention pertains to an electronic coolant valve with a flexible sealing membrane. 
     BACKGROUND 
     Although there have been many changes and improvements in vehicle cooling systems for internal combustion engines over the last few decades, the wax pill actuated coolant valve (thermostat) has remained basically unchanged since its inception. With the increase in government mandated fuel economy regulations, companies are increasingly looking for new technology that will reduce the parasitic losses and improve efficiency of internal combustion engines. Furthermore, the introduction of hybrid and full electric vehicle powertrains has introduced new powertrain coolant and thermal management complexities due to the need to control the temperature of batteries, inverter electronics, eMotors, etc. These trends lead to the need for more intelligently controlled coolant valves. 
     Some thermostat valve manufacturers have introduced a heated wax design in which a heating element is used to expand the wax to open the valve. This provides a direct electric actuation mechanism, but does not provide for precise control. Other valve manufacturers have prototype designs which use a brushless DC (BLDC) motor and gear train for actuating the valves. There also is a controlled coolant valve design that employs a rotary design actuated by a BLDC gearmotor. 
     SUMMARY OF THE INVENTION 
     The present invention comprises an electronic coolant valve which selectively allows various amounts of coolant, or no coolant, to flow through a passageway. The invention is an improvement over known thermostats and uses a stepper or brushless motor with an integrated lead (drive) screw and a flexible sealing membrane actuated by the lead screw. In a preferred embodiment of the invention, a motor and lead screw is utilized to transfer rotary motion into a threaded nut member. The threaded nut member transforms the rotary motion into linear motion which expands or retracts a flexible sealing membrane. Anti-rotation members can be provided to prevent rotation of the nut member and sealing membrane. 
     The act of expanding a flexible sealing membrane forces out the mid-section of the membrane allowing it to contact the sides of a manifold passageway and block off and prevent coolant flow. Conversely, retracting the flexible sealing membrane contracts and extends it, allowing coolant to freely pass through the passageway. Infinite control of the flow of fluid through the passageway exists between the totally open and totally closed conditions. 
     In another embodiment of the invention, the drive screw could be rotated by the motor and translate in a longitudinal manner. The flexible membrane is attached to the end of the drive screw but does not rotate with the drive screw. The longitudinal movement of the drive screw either expands the membrane or extends it, depending on the direction of movement of the drive screw. 
     In other embodiments of the invention, the flexible sealing membrane that expands and contracts can incorporate features that assist in controlling the flexible nature of the membrane. The features include changing the thickness of the membrane at various places and adding circumferential grooves at certain locations. The membrane may also have a uniform thickness throughout its length. 
     The flexible sealing membrane also can seal the mechanical interfaces from the coolant. This insures the mechanical actuators stay free of coolant, sludge and system contamination. 
     Further objects, features and benefits of the invention will become apparent to persons skilled in the art from the following description of the preferred embodiments when also viewed in accordance with the attached drawings and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates an embodiment of the present invention. 
         FIG. 2  is a cross-section taken along line  2 - 2  in  FIG. 1 . 
         FIG. 3  illustrates an embodiment of an electric coolant valve with a flexible seal in accordance with an embodiment of the present invention, the valve being in an open state. 
         FIG. 4  illustrates the electronic coolant valve as shown in  FIG. 3  in a metered state. 
         FIG. 5  illustrates the electronic cooling valve as set forth in  FIG. 3  in a closed state. 
         FIG. 6  illustrates another embodiment of the present invention utilizing multiple valves in a manifold. 
         FIG. 7  illustrates still another embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purpose of promoting and understanding the principles of the present invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe them. It will nevertheless be understood that no limitation as to the scope of the invention is hereby intended. The invention includes any alternatives and other modifications in the illustrated devices and described methods and further applications of the principles of the invention which would normally occur to persons of ordinary skill in the art to which the invention relates. 
     An embodiment of the present invention is shown schematically in  FIG. 1  and referred to generally by the reference numeral  10 .  FIG. 2  is a cross-section taken along lines  2 - 2  in  FIG. 1 . As shown in  FIG. 1 , the electronic coolant valve  10  is positioned in an inlet channel or passageway  12  of a manifold  14  or similar mechanism. The electronic coolant valve  10  is adapted to either prohibit, meter, or open the passageway  12  relative to the flow of coolant through the passageway to the outlet channel  16 . 
     The electronic coolant valve has an actuator member  20  that rotates and drives a threaded lead screw  22 . The lead screw can also be called a drive screw. A threaded sleeve member  32  is positioned on the end of the lead screw  22  and secured to a flexible membrane  30  by a fastener  34 , such as a rivet. Rotation of the drive screw  22  moves the sleeve member  32  in a longitudinal direction which in turn radially expands or contracts the flexible member  30 . 
     The actuator member can be any type of electric motor with the ability to transfer rotary motion into rotational movement of the lead screw  22 . For example, the actuator can be a stepper motor or a brushless DC (BLDC) motor. The flexible membrane  30  can be of any type of real or synthetic rubber or elastomer material, such as silicone, but preferably is made of ethylene propylene diene monomer (EPDM). 
     The actuation of the electric motor  20  rotates the lead screw to extend or retract the membrane  30  radially in the inlet channel or passageway  12 . If the lead screw is rotated in one direction, the flexible membrane expands radially outwardly toward the walls of the flow channel. Similarly, when the electronic motor rotates the lead screw in the opposite direction, the membrane  30  is stretched (i.e. pulled in radially toward the lead screw), opening the passageway to allow flow of the coolant material into the outlet channel  16 . 
     To prevent rotation of the threaded sleeve member  32  as the lead screw  22  rotates, anti-rotation guide members  40  and  42  are provided. Guide members  40  are generally “U” shaped members having a longitudinal groove or channel  41 . The guide members  40  are affixed to the sleeve member  32 . Guide members  42  are elongated slat-type members which are fixedly secured to retainer member  38  at one end, and positioned in channels  41  at the other end. As the lead screw  22  rotates, the guide members  42  slide longitudinally in guide members  40  and prevent rotation of the sleeve member  32  and the flexible membrane  30 . 
     Although a pair of mating guide members  40  and  42  are present in the embodiment depicted in the Figures, there can be any number of guide members provided, such as 3, 4, 5, etc. Regardless of the number of mating guide members provided, they preferably are spread uniformly around the circumference of the sleeve member  32  in order to allow the mechanism to operate more easily and uniformly. 
     In another embodiment of the invention, the drive screw can be moved longitudinally by rotation of the motor  20 , such as by a worm gear. In this embodiment, the flexible membrane is attached to the distal end of the drive screw with a rotational mechanism which allows rotation of the drive screw, but prevents rotation of the flexible membrane. A threaded sleeve member and anti-rotational guides are not necessary. Thus, as the drive screw moves longitudinally in one direction, the flexible membrane expands radially outwardly. As the drive screw moves longitudinally in the other direction, the flexible membrane is retracted radially inwardly. 
     The sealing member which preferably is a flexible membrane, can have a uniform thickness throughout, or the thickness can be modified in certain locations to assist in better operation of the invention. Some of the various thickness embodiments that are possible are shown in the drawings. 
     It is also possible to provide one or more external circumferential grooves in the membrane as shown in  FIGS. 3-5  and  7 . The grooves assist in controlling the direction and amount of contraction and expansion of the membrane. Other embodiments can have a series of grooves either circumferentially or longitudinally for the same purpose. The area of thinner cross-section and circumferential grooves can provide hinge-points to allow ease of expansion of the flexible member. 
     The sealing membrane also helps seal the actuator member from the coolant or liquid flow. In this regard, it is preferred that the membrane contact and seal against the motor mount or retainer members  38 ,  64 . This is shown in  FIGS. 1 ,  2 - 4 , and  6 . 
       FIGS. 3-5  depict various stages in the activation of an electronic coolant valve with a flexible seal in accordance with a preferred embodiment of the invention. In this embodiment, the electronic valve member  50  is positioned in an inlet channel or passageway  52  where it is used to regulate the flow of coolant from the inlet channel to the outlet channel  54 . The lead screw  60  is positioned inside a flexible membrane  62  and attached to an electronic actuator (not shown), such as a BLDC motor. In this regard, the lead screw is inserted through a motor mount or retainer member  64 . 
     A retainer fastener, such as a rivet  70  is positioned at the end of the threaded sleeve member  72  securing the sleeve member to the flexible membrane  62 . 
     Anti-rotation guide members  80 ,  82  are also provided in the coolant valve in order to prevent the sleeve member  72  and flexible membrane  62  from rotating with the lead screw. These guide members can be the same as guide members  40 ,  42  discussed above and can operate in the same manner. 
     As mentioned above,  FIGS. 3-5  show various stages of operation of an electronic cooling valve and the expansion and contraction of the flexible membrane. In  FIG. 3 , the flexible membrane  62  is extended longitudinally by rotation of the lead screw and movement of the sleeve member  72  in a vertically downward direction, thus opening the manifold channel  52  to full passage of coolant therethrough. 
     In contrast, in  FIG. 5 , the lead screw has pulled the sleeve member  72  in a vertical upward direction in the Figure, thus radially expanding the membrane  62  until it makes contact and seals against the inside surface of the inlet flow channel. This prevents flow of coolant through the manifold and into the outlet channel or passageway  54 . 
       FIG. 4  shows a representative metered state of the electronic coolant valve. In this Figure, the lead screw has been rotated and the sleeve member  72  has been moved in the vertical direction in order to expand or contract the flexible membrane radially to a certain extent. In this metered state, the flow of coolant through the manifold from the inlet to the outlet is restricted. By regulating the vertical position of the sleeve member and the corresponding amount of expansion and/or contraction of the flexible membrane, as shown in  FIG. 4 , the flow of coolant through the manifold can be virtually infinitely adjusted. 
     Another embodiment of the invention is shown in  FIG. 6  and referred to generally by the reference numeral  100 . This embodiment attaches a plurality of electronic cooling valves  102 ,  104 ,  106  attached to a common manifold  108 . The valves are preferably the same as the valves described above which have sealing members which meter the flow of fluid through a passageway. Coolant flow entering through inlet channel  110  is then separately metered or adjusted through a plurality of outlets  112 ,  114  and  116 . Each of the electronic cooling valves  102 ,  104  and  106  has its own actuator member (not shown). Preferably the actuators consist of stepper motors or BLDC motors in the same manner as the embodiment shown in  FIGS. 1-5 . This embodiment allows the metering of coolant to multiple circuits. 
     Another embodiment of the invention is shown in  FIG. 7  and referred to generally by the reference numeral  150 . In this embodiment, two opposing sealing members  50  are provided, each with a flexible sealing membrane  62 . The housing or manifold inlet channel  152  is positioned between two opposing sealing members  50  and has an outlet at each end  54  downstream of the sealing sections. Each of the flexible membranes  62  can be extended or retracted by rotation of a lead screw  60  attached to an electric motor actuator of the type described above with reference to  FIGS. 1-5 . 
     The two flexible sealing members in the embodiment shown in  FIG. 7  could act as a toggle and infinitely vary the two valves between their open and closed conditions. In this manner, when one section is in the fully closed state, the opposing section could be in the fully opened state and vice versa. The percentage of being opened and closed of each section could be varied infinitely and inversely with respect to each other. 
     Although the invention has been described with respect to preferred embodiments, it is to be also understood that it is not to be so limited since changes and modifications can be made therein which are within the full scope of this invention as detailed by the following claims.