Abstract:
A system for operating a valve including a motor shaft driven by a motor, a cam, a non-contact sensor, and a butterfly valve plate mounted on a butterfly valve shaft. The cam has an exterior profile and is mounted to the motor shaft. The non-contact sensor is proximate to the cam&#39;s exterior profile. The butterfly shaft is coupled to the motor shaft. A selected position of the butterfly valve plate may be set by activating the motor to a position determined by sensing the cam profile by the non-contact sensor.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims one or more inventions which were disclosed in Provisional Application No. 61/042,824 filed Apr. 7, 2008, entitled “MOTOR OPERATED BUTTERFLY VALVE”. The benefit under 35 USC §119(e) of the United States provisional application is hereby claimed, and the aforementioned application is hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention pertains to the field of valves. More particularly, the invention pertains to a motor operated butterfly valve. 
         [0004]    2. Description of Related Art 
         [0005]    Prior art electric exhaust gas recirculation (EGR), turbo charger waste gate, and cooler bypass, and exhaust gas restricting valve systems suffer from multiple problems. Common problems associated with the electric operated valve systems are soot migrating into the motor, rotor slippage and the encoder/sensors of the system failing due to the high ambient and radiant temperatures in the system. Other problems such as internal leakage can also occur with improper sealing of the butterfly valve plate. 
         [0006]      FIGS. 16 and 17  show schematics of prior art butterfly valves sealing with the valve housing. 
         [0007]      FIG. 16  shows a prior art butterfly valve plate  120  l mounted on a shaft  124  sealing on a first flat side  120   a  of the butterfly valve plate  120  with a first flat seat face  123   b  and sealing on an opposing second flat side  120   b , opposite the first flat side  120   a  of the butterfly valve plate  120  with a second flat seat face  123   c  formed opposite the first flat seat face  123   b . The first and second seat faces  123   b ,  123   c  are formed integrally with the valve housing  123 . There are numerous problems with this butterfly valve design. One of the problems associated with this type of butterfly valve is that exhaust coking of soot can easily build up between the butterfly valve plate  120  and the flat seal faces of the seats  123   b ,  123   c , causing internal leakage problems. It is also difficult to mate both seal faces flat sides  120   a ,  120   b  of the with the butterfly valve plate  120  at the same time. 
         [0008]      FIG. 17  shows another prior art butterfly valve. The butterfly valve plate  220  seals against the inner diameter  223   a  of the valve housing  223 . From a manufacturing standpoint, it is difficult to manufacture and have the prior art butterfly valve plate  220  seal uniformly with the inner diameter  223   a  of the valve housing  223 . If the butterfly valve plate  220  does not seal uniformly with the inner diameter  223   a  of the valve housing  223 , high internal leakage results. Additionally, soot coking builds up in the inner diameter  223   a  of the valve housing  223 , where the butterfly valve plate  220  has to seal. 
       SUMMARY OF THE INVENTION 
       [0009]    An electric driven valve system that uses a non-contact cam profile sensor to control a butterfly valve in the pneumatic management systems of a combustion engine. The sensor detects the motion of the cam, independent of actual motor rotation, providing closed loop control. Since the sensor is detecting the motion of the cam independent of the actual motor rotor rotation, if the motor rotor does slip, it will not affect control of the butterfly valve in the pneumatic management system of the combustion engine. 
         [0010]    Butterfly valve plate designs are also disclosed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0011]      FIG. 1  shows a side view of a motor operated valve of a first embodiment of the present invention. 
           [0012]      FIG. 2  shows a sectional view of the motor operated valve of the first embodiment of the present invention. 
           [0013]      FIG. 3  shows a side view of a motor operated valve of a second embodiment of the present invention. 
           [0014]      FIG. 4  shows a sectional view of the motor operated valve of the second embodiment of the present invention. 
           [0015]      FIG. 5  shows a side view of the butterfly valve. 
           [0016]      FIG. 6  shows an example of a cam profile. 
           [0017]      FIG. 7  shows another example of a cam profile. 
           [0018]      FIG. 8  shows a view of the motor operated valve of the third embodiment of the present invention. 
           [0019]      FIG. 9  shows a cross-section of the motor operated valve of the third embodiment of the present invention. 
           [0020]      FIG. 10  shows an enlarged view of the bevel gears of the third embodiment of the present invention. 
           [0021]      FIG. 11  shows a cross-section of a motor operated valve of a fourth embodiment of the present invention. 
           [0022]      FIG. 12  shows another cross-section of the motor operated valve of the fourth embodiment of the present invention. 
           [0023]      FIG. 13   a  shows another side view of the butterfly valve plate of the present invention.  FIG. 13   b  shows an exploded view of the butterfly valve plate shown in  FIG. 13   a.    
           [0024]      FIG. 14  shows another butterfly valve plate of the present invention. 
           [0025]      FIG. 15  shows another example of a butterfly valve plate of the present invention. 
           [0026]      FIG. 16  shows an example of a prior art butterfly valve plate. 
           [0027]      FIG. 17  shows another example of a prior art butterfly valve plate. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]      FIGS. 1-2  show a motor operated butterfly valve of the first embodiment. A motor  10  is connected to valve housing  23 . The motor  10  drives a motor shaft  18  with a cam  14  on an end. The cam  14  is present within the valve housing  23  at a first end adjacent to the motor  10 . A non-contact sensor  12  within the valve housing  23  is aligned and positioned with the cam  14  to sense the profile of the cam  14  as it rotates. The cam profile is not limited to profile shown in any of the figures. If desired, only a portion of the cam profile may be sensed, as shown in  FIGS. 6-7 , where 180 degrees and 270 degrees of the cam are being sensed. The information from the non-contact sensor  12  is sent and monitored by the ECU (not shown). Based on the information from the non-contact sensor  12  and other engine parameters the ECU adjusts the motor  10 , in turn adjusting the position of the butterfly valve  20 . 
         [0029]    A first end  24   a  of a butterfly shaft  24  is received by a flange  8  on the cam  14  within the valve housing  23 . The butterfly shaft  24  extends the length of the housing  23  to a second end  24   b . The second end  24   b  of the butterfly shaft  24  fits into a bearing  19 . The cap  22  is used to keep out environmental contamination and contains any soot passed the butterfly shaft  24  to bearing  19  fit from exiting the assembly. The butterfly valve plate  20  is received within a cylindrical portion  23   a  of the valve housing  23  and is connected to the butterfly shaft  24  between the first end  24   a  and the second end  24   b  of the butterfly shaft  24  and between bearings  19 . The cylindrical portion  23   a  of the valve housing  23  has an integrally formed angled seat  23   c  within the inner diameter  23   b.    
         [0030]    As shown in  FIGS. 5 ,  13   a , and  13   b  the butterfly valve plate  20  has a first side  20   a  and a second side  20   b , the first side  20   a  being opposite from the second side  20   b . The outer circumference of the butterfly valve plate  20  has angled end faces  20   c  that make line contact with an edge or corner  23   d  of the integrally formed angled seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . When the butterfly shaft  24  is rotated, moving the butterfly valve plate  20  to a sealing position, the angled end face  20   c  formed on the outer circumference of the butterfly valve plate  20  on a first side  20   a  and a second side  20   b  seals at line contact with the corner or edge  23   d  of the integrally formed seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . By having the seal formed between the edge  23   d  of integrally formed seat  23   c  and the angled face  20   c  on the outer circumference of the butterfly valve plate  20 , soot does not coke up and internal leakage is low. Because of the edge sealing and the ability to brinell (coin) the mating surfaces of the angular face and the edge so that they conform exactly to one another, the seating stresses are high as compared with other designs. This enhances the low internal leakage sealing ability. 
         [0031]      FIG. 14  shows an example of different geometry formed on the outer circumference of the butterfly valve plate  20 . Instead of only a small portion of the outer circumference of the butterfly valve plate  20  having an angled edge as in  FIGS. 13   a  and  13   b , a significantly larger portion of the outer circumference of the butterfly valve plate has an angled edge. In other words, the angled edge extends from the tip of the outer circumference of the butterfly valve plate to the sides of the butterfly valve plate  20   a ,  20   b.  As in  FIGS. 5 ,  13   a , and  13   b , when the butterfly shaft  24  is rotated, moving the butterfly valve plate  20  to a sealing position, the large angled end face  20   c  formed on the outer circumference of the butterfly valve plate  20  on a first side  20   a  and a second side  20   b  seals at line contact with the corner or edge  23   d  of the integrally formed seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . By having the seal formed between the edge  23   d  of integrally formed seat  23   c  and the large angled face  20   c  on the outer circumference of the butterfly valve plate  20 , soot does not coke up and internal leakage is low. Because of the edge sealing and the ability to brinell (coin) the mating surfaces of the angular face and the edge so that they conform exactly to one another, the seating stresses are high as compared with other designs. This enhances the low internal leakage sealing ability. 
         [0032]      FIG. 15  shows a butterfly valve plate  64  of an alternate embodiment in which the integrally formed seat  63   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  has an angled seat  63   d  and the butterfly valve plate  64  has squared outer edges  64   a . When the butterfly shaft  24  is rotated, moving the butterfly valve plate  64  to a sealing position as shown in the figure, the edges  64   a  on the outer circumference of the butterfly valve plate  64  seals at line contact with the angled edge  63   d  of the integrally formed seat  63   c  on the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . 
         [0033]    The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  as shown in  FIGS. 5 ,  13   a ,  13   b ,  14 , and  15  when mating with the edge  23   d  or angular face  63   d  on the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  also prevents the butterfly valve plate  20 ,  64  from wedging, ensuring that the butterfly valve plate  20 ,  64  hits the valve housing  23  at two positive stops. The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  also reduces the required torque required by the motor  10  since the butterfly valve plate  20 ,  64  doesn&#39;t wedge with the cylindrical portion  23   a  of the valve housing  23 . The edge  64   a  or angular face  20   c  on the outer circumference of the butterfly valve plate  64 ,  20  and the edge  23   d  or angular face  63   d  of the seat prevents soot build up since soot and debris cannot accumulate on the edges of the edge seal design. The design of the butterfly valve plate  20 ,  64  and the design of the seat provides low internal leakage when the butterfly valve plate  20 ,  64  is closed, giving superior low leakage performance, improving the dynamic flow range of the valve. Because of the edge sealing and the ability to brinell (coin) the mating surfaces of the angular face and the edge so that they conform exactly to one another, the seating stresses are high as compared with other designs. This enhances the low internal leakage sealing ability. 
         [0034]    In any of the above embodiments, the edges  23   d  of the integrally formed seat and the angular face  20   c  of the butterfly valve plate  20  or the angular face  63   d  of the integrally formed seat and the edge  64   a  of the butterfly valve plate  64 , the tolerance due to manufacturing yielding the seat and the butterfly valve plate may be coined out such that the entire outer circumference of the butterfly valve plate hits the seat at the same time. In a preferred embodiment, the materials of the integrally formed seat and the material of the butterfly valve plate have nearly the same coefficient of linear thermal expansion, such that no change is leakage performance is present over a temperature range. 
         [0035]    The mating of the edge seals on the outer circumference of the butterfly valve plate with the seat in the cylindrical housing, regardless of whether the angular edge is on the butterfly valve plate or the seat or the edge or corner is on the butterfly valve plate or the seat, results in an angular face to angular edge mating. Planar surface to surface contact between the butterfly valve plate and seat of the cylindrical portion of the valve housing does not occur. 
       EXAMPLE 1 
       [0036]    Bench tests of a 2.570 in diameter butterfly plate were run at 10 through 80 PSIG (pounds per square inch gauge) with edge sealing as disclosed above as resulted in the following standard cubic feet per minute of leakage. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                   
               
               
                 Pounds per  
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 square 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 inch gauge  
                 10 
                 20 
                 30 
                 40 
                 50 
                 60 
                 70 
                 80 
               
               
                 (PSIG) 
                 PSIG 
                 PSIG 
                 PSIG 
                 PSIG 
                 PSIG 
                 PSIG 
                 PSIG 
                 PSIG 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Present  
                 6.4 
                 9.4 
                 13.9 
                 21.0 
                 28 
                 36.9 
                 45.6 
                 56.5 
               
               
                 Invention 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Butterfly Valve 
                 scfm 
                 scfm 
                 scfm 
                 scfm 
                 scfm 
                 scfm 
                 scfm 
                 scfm 
               
               
                 Plate with edge 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 sealing in  
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 standard 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 cubic feet per 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 minute (scfm) 
               
               
                   
               
             
          
         
       
     
         [0037]    At 40 PSIG, the prior art sealing technique shown in  FIG. 16 , the amount of leakage was 100 standard cubic feet per minute. The present invention provides five times better leakage rate at 40 PSIG. 
         [0038]    The flange  8  of the cam  14  also receives a spiral spring  16 . The spring  16  biases the butterfly valve plate  20  to a closed position. Seals  25  are present between the butterfly shaft  24  and the valve housing  23  at the first end  24   a  of the butterfly shaft  24  and at the second end  24   b  of the butterfly shaft  24  preventing soot and debris from entering into the motor  10  and other parts of the assembly. The butterfly shaft  24  and the motor shaft  18  may be formed of one common shaft. 
         [0039]    The motor  10  may be a stepper motor or any other type of electric motor. 
         [0040]      FIGS. 3-4  show a motor driven butterfly valve of a second embodiment. A motor  10  is connected to a valve housing  23  through a cooler  30 . The motor  10  drives a motor shaft  18  having a first end  18   a  with cam  14 . Seal  31  on the motor shaft  18  prevents exhaust soot and debris from entering into the motor  10 . A non-contact sensor  12  is aligned and positioned with cam  14  to sense the profile of the cam  14  as it rotates. The cam profile is not limited to profile shown in any of the figures. If desired, only a portion of the cam profile may be sensed, as shown in  FIGS. 6-7  where 180 degrees and 270 degrees of the cam are being sensed. The information from the non-contact sensor  12  is sent to and monitored by the ECU (not shown). Based on the information from the non-contact sensor  12  and other engine parameters the ECU adjusts the motor  10 , in turn adjusting the position of the butterfly valve  20 . 
         [0041]    The second end  18   b  of the motor shaft  18  is connected to the first end  24   a  of a butterfly shaft  24  through coupling  37 , for example a hex pin drive. The coupling  37  also serves as a thermal break between the butterfly shaft  24  and motor shaft  18 . Adjacent to the motor  10  is a cooler  30  for cooling the seals  31  and the motor  10 . The butterfly shaft  24  extends the length of the housing to a second end. The second end  24   b  of the butterfly shaft  24  fits into a bearing  19 . The cap  22  is used to keep out environmental contamination and contains any soot passed the butterfly shaft  24  to bearing  19  fit from exiting the assembly. The butterfly valve plate  20  is received within a cylindrical portion  23   a  of the valve housing  23  and is connected to the butterfly shaft  20  between the first end  24   a  and the second end  24   b  of the butterfly shaft  24 . 
         [0042]    Bearing  19  are present between the butterfly shaft  24  and the valve housing  23  at the first end  24   a  of the butterfly shaft  24  and at the second end  24   b  of the butterfly shaft  24 . 
         [0043]    As shown in  FIGS. 5 ,  13   a , and  13   b  the butterfly valve plate  20  has a first side  20   a  and a second side  20   b , the first side  20   a  being opposite from the second side  20   b . The outer circumference of the butterfly valve plate  20  has angled end faces  20   c  that make line contact with an edge or corner  23   d  of the integrally formed angled seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . When the butterfly shaft  24  is rotated, moving the butterfly valve plate  20  to a sealing position, the angled end face  20   c  formed on the outer circumference of the butterfly valve plate  20  on a first side  20   a  and a second side  20   b  seals at line contact with the corner or edge  23   d  of the integrally formed seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . By having the seal formed between the edge  23   d  of integrally formed seat  23   c  and the angled face  20   c  on the outer circumference of the butterfly valve plate  20 , soot does not coke up and internal leakage is low. Because of the edge sealing and the ability to brinell (coin) the mating surfaces of the angular face and the edge so that they conform exactly to one another, the seating stresses are high as compared with other designs. This enhances the low internal leakage sealing ability. 
         [0044]    The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  as shown in  FIGS. 5 ,  13   a ,  13   b ,  14 , and  15  when mating with the edge  23   d  or angular face  63   d  on the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  also prevents the butterfly valve plate  20 ,  64  from wedging, ensuring that the butterfly valve plate  20 ,  64  hits the valve housing  23  at two positive stops. The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  also reduces the required torque required by the motor  10  since the butterfly valve plate  20 ,  64  doesn&#39;t wedge with the cylindrical portion  23   a  of the valve housing  23 . The edge  64   a  or angular face  20   c  on the outer circumference of the butterfly valve plate  64 ,  20  and the edge  23   d  or angular face  63   d  of the seat prevents soot build up since soot and debris cannot accumulate on the edges of the edge seal design. The design of the butterfly valve plate  20 ,  64  and the design of the seat provides low internal leakage when the butterfly valve plate  20 ,  64  is closed, giving superior low leakage performance, improving the dynamic flow range of the valve. 
         [0045]    In any of the above embodiments, the edges  23   d  of the integrally formed seat and the angular face  20   c  of the butterfly valve plate  20  or the angular face  63   d  of the integrally formed seat and the edge  64   a  of the butterfly valve plate  64 , the tolerance due to manufacturing yielding the seat and the butterfly valve plate may be coined out such that the entire outer circumference of the butterfly valve plate hits the seat at the same time. In a preferred embodiment, the materials of the integrally formed seat and the material of the butterfly valve plate have nearly the same coefficient of linear thermal expansion, such that no change is leakage performance is present over a temperature range. 
         [0046]    Alternatively, as shown in  FIG. 15 , the butterfly valve plate may have an squared outer edge and the and the integrally formed seat in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  has an angled seat. 
         [0047]    The mating of the edge seals on the outer circumference of the butterfly valve plate with the seat in the cylindrical housing, regardless of whether the angular edge is on the butterfly valve plate or the seat or the edge or corner is on the butterfly valve plate or the seat, results in an angular face to angular edge mating. Planar surface to surface contact between the butterfly valve plate and seat of the cylindrical portion of the valve housing does not occur. Because of the edge sealing and the ability to brinell (coin) the mating surfaces of the angular face and the edge so that they conform exactly to one another, the seating stresses are high as compared with other designs. This enhances the low internal leakage sealing ability. 
         [0048]    Tube  17  between the motor  10  and the housing  23  which includes the coupling  37  provides a thermal break between the motor  10  and the housing  23 , allows proper alignment between the motor  10  and housing  23 , and an enclosure to prevent soot from escaping the assembly. 
         [0049]    The motor  10  may be a stepper motor or any other type of electric motor. 
         [0050]      FIGS. 8-10  show a motor operated butterfly valve of a third embodiment. A motor  10  is connected to valve housing  23 . The motor  10  drives a motor shaft  18  having a first end  18   a  with cam  14 . A non-contact sensor  12  is aligned and positioned with cam  14  to sense the profile of the cam  14  as it rotates. The cam profile is not limited to profile shown in any of the figures. If desired, only a portion of the cam profile may be sensed, as shown in  FIGS. 6-7  where 180 degrees and 270 degrees of the cam are being sensed. The information from the non-contact sensor  12  is sent to the ECU (not shown). Based on the information from the non-contact sensor  12  and other engine parameters the ECU adjusts the motor  10 , in turn adjusting the position of the butterfly valve  20 . 
         [0051]    The second end  18   b  of the motor shaft  18  has a first bevel gear  40  mounted thereon. The first bevel gear  40  mates with a second bevel gear  42  mounted on a first end  24   a  of a butterfly shaft  24 . The butterfly shaft  24  extends the length of the housing  23  to a second end. The second end  24   b  of the butterfly shaft  24  fits into a bearing  19 . The cap  22  is used to keep out environmental contamination and contains any soot passed the butterfly shaft  24  to bearing  19  fit from exiting the assembly. The butterfly valve plate  20  is received within the cylindrical portion  23   a  of the valve housing  23  and is connected to the butterfly shaft  24  between the first end  24   a  and the second end  24   b  of the butterfly shaft  24  and between bearings  19 . A thermal break  43  is present between the motor housing  11  and the valve housing  23 . Tube  17  between the motor housing  11  and the valve housing  23  which includes bevel gear set  40 ,  42  provides an additional thermal break between the motor housing  11  and the valve housing  23 , allows proper alignment between the motor housing  11  and valve housing  23 , and an enclosure to prevent soot from escaping the assembly. 
         [0052]    Seals  44  are present between the motor shaft and the motor and may be cooled by water or oil by including passages in the housing  23 . 
         [0053]    As shown in  FIGS. 5 ,  13   a , and  13   b  the butterfly valve plate  20  has a first side  20   a  and a second side  20   b , the first side  20   a  being opposite from the second side  20   b . The outer circumference of the butterfly valve plate  20  has angled end faces  20   c  that make line contact with an edge or corner  23   d  of the integrally formed angled seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . When the butterfly shaft  24  is rotated, moving the butterfly valve plate  20  to a sealing position, the angled end face  20   c  formed on the outer circumference of the butterfly valve plate  20  on a first side  20   a  and a second side  20   b  seals at line contact with the corner or edge  23   d  of the integrally formed seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . By having the seal formed between the edge  23   d  of integrally formed seat  23   c  and the angled face  20   c  on the outer circumference of the butterfly valve plate  20 , soot does not coke up and internal leakage is low. Because of the edge sealing and the ability to brinell (coin) the mating surfaces of the angular face and the edge so that they conform exactly to one another, the seating stresses are high as compared with other designs. This enhances the low internal leakage sealing ability. 
         [0054]    The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  as shown in  FIGS. 5 ,  13   a ,  13   b ,  14 , and  15  when mating with the edge  23   d  or angular face  63   d  on the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  also prevents the butterfly valve plate  20 ,  64  from wedging, ensuring that the butterfly valve plate  20 ,  64  hits the valve housing  23  at two positive stops. The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  also reduces the required torque required by the motor  10  since the butterfly valve plate  20 ,  64  doesn&#39;t wedge with the cylindrical portion  23   a  of the valve housing  23 . The edge  64   a  or angular face  20   c  on the outer circumference of the butterfly valve plate  64 ,  20  and the edge  23   d  or angular face  63   d  of the seat prevents soot build up since soot and debris cannot accumulate on the edges of the edge seal design. The design of the butterfly valve plate  20 ,  64  and the design of the seat provides low internal leakage when the butterfly valve plate  20 ,  64  is closed, giving superior low leakage performance, improving the dynamic flow range of the valve. 
         [0055]    In any of the above embodiments, the edges  23   d  of the integrally formed seat and the angular face  20   c  of the butterfly valve plate  20  or the angular face  63   d  of the integrally formed seat and the edge  64   a  of the butterfly valve plate  64 , the tolerance due to manufacturing yielding the seat and the butterfly valve plate may be coined out such that the entire outer circumference of the butterfly valve plate hits the seat at the same time. In a preferred embodiment, the materials of the integrally formed seat and the material of the butterfly valve plate have nearly the same coefficient of linear thermal expansion, such that no change is leakage performance is present over a temperature range. 
         [0056]    Alternatively, as shown in  FIG. 15 , the butterfly valve plate may have an squared outer edge and the and the integrally formed seat in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  has an angled seat. 
         [0057]    The mating of the edge seals on the outer circumference of the butterfly valve plate with the seat in the cylindrical housing, regardless of whether the angular edge is on the butterfly valve plate or the seat or the edge or corner is on the butterfly valve plate or the seat, results in an angular face to angular edge mating. Planar surface to surface contact between the butterfly valve plate and seat of the cylindrical portion of the valve housing does not occur. 
         [0058]    The motor  10  may be a stepper motor or any other type of electric motor. 
         [0059]    The ratio between the first bevel gear  40  and the second bevel gear  42  can vary and may be equal or different. Other gear set forms may also be used to accomplish the same function as shown in the Figures. 
         [0060]      FIGS. 11-12  show a motor driven butterfly valve of a fourth embodiment. In this embodiment, the second bevel gear  62  attached to the butterfly shaft  24  has grooves  78  for receiving balls or pins  70  that key the second bevel gear  62  to corresponding mating grooves  72  on the butterfly shaft  24 . The lock and key between the grooves  78  and the balls or pins  70  prevents the second bevel gear  62  rotating on the shaft  24  but allows the bevel gear  62  to slide along the axis of the butterfly shaft  24  via the spring load from a spring  76  present between the valve housing  23  or a retainer mounted on the butterfly shaft  24  as shown and the second bevel gear  62 . The second bevel gear  62  will butt up against a face of the thrust bearing  68  at the proper aligned position to mate with the first bevel gear  40 . It should be noted that the joint design of the bevel gear to the butterfly shaft  24  acts as a thermal break as well as the gear set  40 ,  42 . 
         [0061]    As shown in  FIGS. 5 ,  13   a , and  13   b  the butterfly valve plate  20  has a first side  20   a  and a second side  20   b , the first side  20   a  being opposite from the second side  20   b . The outer circumference of the butterfly valve plate  20  has angled end faces  20   c  that make line contact with an edge or corner  23   d  of the integrally formed angled seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . When the butterfly shaft  24  is rotated, moving the butterfly valve plate  20  to a sealing position, the angled end face  20   c  formed on the outer circumference of the butterfly valve plate  20  on a first side  20   a  and a second side  20   b  seals at line contact with the corner or edge  23   d  of the integrally formed seat  23   c  in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23 . By having the seal formed between the edge  23   d  of integrally formed seat  23   c  and the angled face  20   c  on the outer circumference of the butterfly valve plate  20 , soot does not coke up and internal leakage is low. Because of the edge sealing and the ability to brinell (coin) the mating surfaces of the angular face and the edge so that they conform exactly to one another, the seating stresses are high as compared with other designs. This enhances the low internal leakage sealing ability. 
         [0062]    The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  as shown in  FIGS. 5 ,  13   a ,  13   b ,  14 , and  15  when mating with the edge  23   d  or angular face  63   d  on the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  also prevents the butterfly valve plate  20 ,  64  from wedging, ensuring that the butterfly valve plate  20 ,  64  hits the valve housing  23  at two positive stops. The angular face  20   c  or edge  64   a  on the outer circumference of the butterfly valve plate  20 ,  64  also reduces the required torque required by the motor  10  since the butterfly valve plate  20 ,  64  doesn&#39;t wedge with the cylindrical portion  23   a  of the valve housing  23 . The edge  64   a  or angular face  20   c  on the outer circumference of the butterfly valve plate  64 ,  20  and the edge  23   d  or angular face  63   d  of the seat prevents soot build up since soot and debris cannot accumulate on the edges of the edge seal design. The design of the butterfly valve plate  20 ,  64  and the design of the seat provides low internal leakage when the butterfly valve plate  20 ,  64  is closed, giving superior low leakage performance, improving the dynamic flow range of the valve. 
         [0063]    In any of the above embodiments, the edges  23   d  of the integrally formed seat and the angular face  20   c  of the butterfly valve plate  20  or the angular face  63   d  of the integrally formed seat and the edge  64   a  of the butterfly valve plate  64 , the tolerance due to manufacturing yielding the seat and the butterfly valve plate may be coined out such that the entire outer circumference of the butterfly valve plate hits the seat at the same time. In a preferred embodiment, the materials of the integrally formed seat and the material of the butterfly valve plate have nearly the same coefficient of linear thermal expansion, such that no change is leakage performance is present over a temperature range. 
         [0064]    Alternatively, as shown in  FIG. 15 , the butterfly valve plate may have an squared outer edge and the and the integrally formed seat in the inner diameter  23   b  of the cylindrical portion  23   a  of the valve housing  23  has an angled seat. 
         [0065]    The mating of the edge seals on the outer circumference of the butterfly valve plate with the seat in the cylindrical housing, regardless of whether the angular edge is on the butterfly valve plate or the seat or the edge or corner is on the butterfly valve plate or the seat, results in an angular face to angular edge mating. Planar surface to surface contact between the butterfly valve plate and seat of the cylindrical portion of the valve housing does not occur. 
         [0066]    The number of grooves, ball or pins is not limited to the number shown in the drawings. 
         [0067]    The butterfly shaft  24  and the motor shaft  18  may be a common shaft. 
         [0068]    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.