Compressor pulse width modulation

Abstract

A scroll compressor includes a capacity modulation system. The capacity modulation system has a piston that is connected to the non-orbiting scroll that disengages the non-orbiting scroll from the orbiting scroll when a pressure chamber is placed in communication with the suction chamber of the compressor. The non-orbiting scroll member moves into engagement with the orbiting scroll when the chamber is placed in communication with the discharge chamber. The engagement between the two scrolls is broken when the pressure chamber is placed in communication with fluid from the suction chamber. A solenoid valve controls the communication between the pressure chamber and the suction chamber. By operating the valve in a pulsed width modulated mode, the capacity of the compressor can be infinitely varied between zero and one hundred percent.

1. A scroll-type machine comprising:
 a first scroll member having a first end plate and a first spiral wrap extending therefrom;  
 a second scroll member having a second end plate and a second spiral wrap extending therefrom, said first and second scroll members being positioned with said first and second spiral wraps interleaved with each other;  
 a drive member for causing said scroll members to orbit relative to one another, whereby said spiral wraps will create pockets of progressively changing volume between a suction pressure zone and a discharge pressure zone;  
 said first and second scroll members being movable between a first relationship in which sealing surfaces of said first and second scroll members are in sealing relationship to close off said pockets and a second relationship wherein at least one of said sealing surfaces of said first and second scroll members are spaced apart to define a leakage path between said pockets; and  
 a fluid operated piston disposed in said discharge pressure zone and secured to said first scroll, said piston being actuatable to apply a force to said first scroll to move said first scroll between said first relationship where said scroll machine operates at substantially full capacity and said second relationship in which said scroll machine operates at substantially zero capacity.  
 
     
     
       2. The scroll-type machine according to  claim 1 , wherein said drive member continues to operate when said first scroll member is in said second relationship. 
     
     
       3. The scroll-type machine according to  claim 2 , wherein said scroll-type machine includes a discharge flow path for conducting compressed fluid from said scroll-type machine and a check valve located within said flow path to prevent reverse flow of said compressed fluid. 
     
     
       4. The scroll-type machine according to  claim 1 , wherein said fluid operated piston is operated in a time pulsed manner to modulate the capacity of said scroll-type machine. 
     
     
       5. The scroll-type machine according to  claim 1 , further comprising a fluid pressure chamber operative to apply said force to said fluid operated piston. 
     
     
       6. The scroll-type machine according to  claim 5 , wherein said force acts in an axial direction. 
     
     
       7. The scroll-type machine according to  claim 6 , further comprising a first passage for supplying a pressurized fluid from said scroll-type machine to said pressure chamber. 
     
     
       8. The scroll-type machine according to  claim 7 , further comprising a valve for controlling flow through said first passage, said valve being operative to vent said pressurized fluid from said pressure chamber to thereby enable said first and second scrolls to move between said first and second relationships. 
     
     
       9. The scroll-type machine according to  claim 8 , wherein said valve is a solenoid operated valve. 
     
     
       10. The scroll-type machine according to  claim 9 , wherein said solenoid operated valve is operated in a pulse width modulated mode. 
     
     
       11. The scroll-type machine according to  claim 8 , further comprising a control module in communication with said valve. 
     
     
       12. The scroll-type machine according to  claim 11 , further comprising at least one sensor in communication with said control module, said control module being operative to control said valve in response to a signal from said sensor. 
     
     
       13. The scroll-type machine according to  claim 7 , further comprising a second passage for venting said pressurized fluid from said pressure chamber. 
     
     
       14. The scroll-type machine according to  claim 1 , wherein said scroll-type machine includes a shell, said fluid operated piston being slidingly received within a fitting secured to said shell. 
     
     
       15. The scroll-type machine according to  claim 14 , wherein said piston and said fitting define a pressure chamber. 
     
     
       16. The scroll-type machine according to  claim 15 , wherein said pressure chamber is in communication with a suction chamber defined by said shell. 
     
     
       17. The scroll-type machine according to  claim 16 , further comprising a valve disposed between said pressure chamber and said suction chamber. 
     
     
       18. The scroll-type machine according to  claim 17 , wherein said valve is a solenoid valve. 
     
     
       19. The scroll-type machine according to  claim 18 , wherein said solenoid valve is operated in a pulse width modulated mode. 
     
     
       20. The scroll-type machine according to  claim 17 , wherein said pressure chamber is in communication with a discharge chamber defined by said shell. 
     
     
       21. The scroll-type machine according to  claim 16 , wherein said solenoid valve is operated in a pulse width modulated mode. 
     
     
       22. The scroll-type machine according to  claim 21 , further comprising a valve disposed between said pressure chamber and both said suction chamber and said discharge chamber. 
     
     
       23. The scroll-type machine according to  claim 22 , further comprising a valve disposed between said pressure chamber and said suction chamber. 
     
     
       24. The scroll-type machine according to  claim 23 , wherein said valve is a solenoid valve. 
     
     
       25. A scroll-type machine comprising:
 a first scroll member having a first end plate and a first spiral wrap extending therefrom;  
 a second scroll member having a second end plate and a second spiral wrap extending therefrom, said first and second scroll members being positioned with said first and second spiral wraps interleaved with each other;  
 a shell housing said first and second scroll members; 
 a drive member for causing said scroll members to orbit relative to one another whereby said spiral wraps will create pockets of progressively changing volume between a suction pressure zone and a discharge pressure zone;  
 said first and second scroll members being movable between a first relationship in which sealing surfaces of said first and second scroll members are in sealing relationship to close off said pockets and a second relationship wherein at least one of said sealing surfaces of said first and second scroll members are spaced apart to define a leakage path between said pockets;  
 a fluid operated piston secured to said first scroll and slidingly received within a bore defined by said shell, said piston being actuatable to apply a force to said first scroll to move said first scroll between said first relationship where said scroll machine operates at substantially full capacity and said second relationship in which said scroll machine operates at substantially zero capacity; and  
 a radially compliant sealing system disposed between said piston and said bore defined by said shell.  
 
     
     
       26. The scroll-type machine according to  claim 25 , further comprising an annular fitting disposed between said shell and said piston, said radially complaint sealing system being disposed between said piston and said fitting. 
     
     
       27. The scroll-type machine according to  claim 25 , wherein said radially complaint sealing system includes a lip seal. 
     
     
       28. The scroll-type machine according to  claim 27 , wherein said radially complaint sealing system includes a floating retainer. 
     
     
       29. The scroll-type machine according to  claim 25 , wherein said radially complaint sealing system includes a floating retainer. 
     
     
       30. A scroll-type machine comprising:
 a first scroll member having a first end plate and a first spiral wrap extending from said first end plate;  
 a second scroll member having a second end plate and a second spiral wrap extending from said second end plate, said first and second scroll members being positioned with said first and second spiral wraps interleaved with each other;  
 a drive member for causing said scroll members to orbit relative to one another whereby said spiral wraps will create pockets of progressively changing volume between a suction pressure zone and a discharge pressure zone;  
 a mechanism for moving said first and second scroll members between a first relationship where sealing surfaces of said first and second scroll members are in sealing relationship to close off said pockets and a second relationship where at least one of said sealing surfaces of said first and second scroll members are spaced apart to define a leak path between said pockets; and  
 a fluid injection system associated with one of said scroll members for injecting a fluid into at least one of said pockets.  
 
     
     
       31. The scroll-type machine according to  claim 30 , wherein said mechanism is operated in a pulse width modulation mode. 
     
     
       32. The scroll-type machine according to  claim 31 , wherein said fluid being injected into said at least one of said pockets is a vapor. 
     
     
       33. The scroll-type machine according to  claim 30 , wherein said mechanism includes a solenoid valve. 
     
     
       34. The scroll-type machine according to  claim 33 , wherein said solenoid valve is operated in a pulse width modulation mode. 
     
     
       35. The scroll-type machine according to  claim 30 , wherein said mechanism includes a fluid operated piston secured to said first scroll, said piston being activatable to apply a force to said first scroll to move said first scroll between said first and second relationships. 
     
     
       36. The scroll-type machine according to  claim 35 , wherein said drive member continues to operate when said first scroll member is in said second relationship. 
     
     
       37. The scroll-type machine according to  claim 35 , wherein said fluid operated piston is operated in a time pulsed manner to modulate the capacity of said scroll-type machine. 
     
     
       38. The scroll-type machine according to  claim 37 , wherein said fluid injection system includes a solenoid valve for controlling flow of said fluid to said one of said scroll members. 
     
     
       39. The scroll-type machine according to  claim 38 , wherein said solenoid valve is operated in a pulse width modulation mode. 
     
     
       40. The scroll-type machine according to  claim 39 , wherein said fluid being injected into one of said pockets is a vapor. 
     
     
       41. The scroll-type machine according to  claim 35 , wherein said fluid being injected into said at least one of said pockets is a vapor. 
     
     
       42. The scroll-type machine according to  claim 30 , wherein said fluid injection system includes a solenoid valve for controlling flow of said fluid to said one of said scroll members. 
     
     
       43. The scroll-type machine according to  claim 42 , wherein said solenoid valve is operated in a pulse width modulation mode. 
     
     
       44. The scroll-type machine according to  claim 43 , wherein said fluid being injected into one of said pockets is a vapor. 
     
     
       45. A scroll-type machine comprising:
 a first scroll member having a first end plate and a first spiral wrap extending from said first end plate;  
 a second scroll member having a second end plate and a second spiral wrap extending from said second end plate, said first and second scroll members being positioned with said first and second spiral wraps interleaved with each other;  
 a drive member for causing said scroll members to orbit relative to one another whereby said spiral wraps will create pockets of progressively changing volume between a suction pressure zone and a discharge pressure zone; and  
 a vapor injection system associated with one of said scroll members for injecting a vapor into at least one of said pockets, said vapor injection system including a valve for controlling said vapor being injected into said at least one of said pockets.  
 
     
     
       46. The scroll-type machine according to  claim 45 , wherein said valve is a solenoid valve. 
     
     
       47. The scroll-type machine according to  claim 46 , wherein said solenoid valve is operated in a pulse width modulation mode. 
     
     
       48. The scroll-type machine according to  claim 47 , wherein said fluid being injected into one of said pockets is a vapor. 
     
     
       49. The scroll- type machine according to    claim 1   , wherein said fluid operated piston is responsive to a discharge pressure in said discharge pressure zone.   
     
     
       50. A scroll- type machine comprising:      a first scroll member having a first end plate and a first spiral wrap extending therefrom;        a second scroll member having a second end plate and a second spiral wrap extending therefrom, said first and second scroll members being positioned with said first and second spiral wraps interleaved with each other;        a shell housing said first and second scroll members;        a drive member for causing said first and second scroll members to orbit relative to one another, whereby said spiral wraps will create pockets of progressively changing volume between a suction pressure zone and a discharge pressure zone;        said first and second scroll members being movable between a first relationship in which sealing surfaces of said first and second scroll members are in sealing relationship to close off said pockets and a second relationship wherein at least one of said sealing surfaces of said first and second scroll members are spaced apart to define a leakage path between said pockets;        a fluid operated piston secured to said first scroll member, said piston being actuatable to apply a force to said first scroll member to move said first scroll member between said first relationship where said scroll machine operates at substantially full capacity and said second relationship in which said scroll machine operates at substantially zero capacity; and        a sealing system operable to provide radial compliance between said first scroll member and said shell.     
     
     
       51. The scroll- type machine according to    claim 50   , further comprising an annular fitting disposed between said shell and said piston, said sealing system being disposed between said piston and said fitting.   
     
     
       52. The scroll- type machine according to    claim 51   , wherein said sealing system includes a seal and a floating retainer.   
     
     
       53. The scroll- type machine according to    claim 50   , wherein said sealing system includes a lip seal.   
     
     
       54. The scroll- type machine according to    claim 53   , wherein said sealing system includes a floating retainer.   
     
     
       55. The scroll- type machine according to    claim 50   , wherein said sealing system includes a floating retainer.