Capacity modulation system for compressor and method

Abstract

A compressor is provided and may include a first compression mechanism, a first valve plate including a first port, and a first manifold including a first cylinder having a first piston disposed therein. The first piston may be movable between a first position opening the first port and a second position closing the first port. The compressor may additionally include a second compression mechanism, a second valve plate including a second port, and a second manifold including a second cylinder having a second piston disposed therein. The second piston may be movable between a first position opening the second port and a second position closing the second port. A valve assembly may move one of the first and second pistons into the first position while maintaining the other of the first and second pistons in the second position.

What is claimed is: 
     
         1 . A compressor comprising:
 a first compression mechanism;   a first valve plate associated with said first compression mechanism and including a first port;   a first manifold disposed adjacent to said first valve plate and including a first cylinder having a first piston disposed therein, said first piston movable relative to said first manifold between a first position separated from said first valve plate opening said first port and a second position contacting said first valve plate closing said first port;   a second compression mechanism;   a second valve plate associated with said second compression mechanism and including a second port;   a second manifold disposed adjacent to said second valve plate and including a second cylinder having a second piston disposed therein, said second piston movable relative to said second manifold between a first position separated from said second valve plate opening said second port and a second position contacting said second valve plate closing said second port; and   a valve assembly operable to modulate a capacity of the compressor by moving said first piston and said second piston between said first position and said second position, said valve assembly moving one of said first piston and said second piston into said first position while maintaining the other of said first piston and said second piston in said second position.   
     
     
         2 . The compressor of  claim 1 , wherein said one of said first piston and said second piston is duty-cycle controlled by said valve assembly. 
     
     
         3 . The compressor of  claim 2 , wherein said other of said first piston and said second piston is in said second position when said one of said first piston and said second piston is duty-cycle controlled by said valve assembly. 
     
     
         4 . The compressor of  claim 2 , wherein said valve assembly includes a first solenoid valve associated with said first piston and a second solenoid valve associated with said second piston. 
     
     
         5 . The compressor of  claim 1 , wherein said first piston includes a first valve element disposed therein and movable relative to said first piston and said second piston includes a second valve element disposed therein and movable relative to said second piston, said first valve element and said second valve element respectively contacting said first valve plate and said second valve plate when said first piston and said second piston are in said second position. 
     
     
         6 . The compressor of  claim 5 , wherein said first piston and said second piston each include an inner volume having a pressurized fluid disposed therein, said pressurized fluid operable to bias said valve elements toward respective ends of said first piston and said second piston. 
     
     
         7 . The compressor of  claim 1 , further comprising a first chamber disposed between a top surface of said first piston and an inner surface of said first cylinder and a second chamber disposed between a top surface of said second piston and an inner surface of said second cylinder, said first chamber and said second chamber selectively receiving a pressurized fluid to move said first piston and said second piston from said first position to said second position. 
     
     
         8 . The compressor of  claim 7 , wherein said valve assembly selectively supplies said pressurized fluid to said first chamber and said second chamber. 
     
     
         9 . The compressor of  claim 8 , wherein said valve assembly supplies said pressurized fluid to said first chamber to cycle said first piston between said first position and said second position at a predetermined duty cycle while maintaining said second piston in said first position. 
     
     
         10 . The compressor of  claim 8 , wherein said valve assembly supplies said pressurized fluid to said first chamber to cycle said first piston between said first position and said second position at a predetermined duty cycle while maintaining said second piston in said second position. 
     
     
         11 . A compressor comprising:
 a first compression mechanism;   a first valve plate associated with said first compression mechanism and including a first port;   a first manifold disposed adjacent to said first valve plate and including a first cylinder having a first piston disposed therein, said first piston movable relative to said first manifold between a first position separated from said first valve plate opening said first port and a second position contacting said first valve plate closing said first port;   a second compression mechanism;   a second valve plate associated with said second compression mechanism and including a second port;   a second manifold disposed adjacent to said second valve plate and including a second cylinder having a second piston disposed therein, said second piston movable relative to said second manifold between a first position separated from said second valve plate opening said second port and a second position contacting said second valve plate closing said second port; and   a valve assembly operable to modulate a capacity of the compressor by moving said first piston and said second piston between said first position and said second position, said valve assembly cycling one of said first piston and said second piston between said first position and said second position at a predetermined duty cycle while maintaining the other of said first piston and said second piston in one of said first position and said second position.   
     
     
         12 . The compressor of  claim 11 , wherein said valve assembly includes a first solenoid valve associated with said first piston and a second solenoid valve associated with said second piston. 
     
     
         13 . The compressor of  claim 11 , wherein said first piston includes a first valve element disposed therein and movable relative to said first piston and said second piston includes a second valve element disposed therein and movable relative to said second piston, said first valve element and said second valve element respectively contacting said first valve plate and said second valve plate when said first piston and said second piston are in said second position. 
     
     
         14 . The compressor of  claim 13 , wherein said first piston and said second piston each include an inner volume having a pressurized fluid disposed therein, said pressurized fluid operable to bias said valve elements toward respective ends of said first piston and said second piston. 
     
     
         15 . The compressor of  claim 11 , further comprising a first chamber disposed between a top surface of said first piston and an inner surface of said first cylinder and a second chamber disposed between a top surface of said second piston and an inner surface of said second cylinder, said first chamber and said second chamber selectively receiving a pressurized fluid to move said first piston and said second piston from said first position to said second position. 
     
     
         16 . The compressor of  claim 15 , wherein said valve assembly selectively supplies said pressurized fluid to said first chamber and said second chamber. 
     
     
         17 . The compressor of  claim 16 , wherein said valve assembly supplies said pressurized fluid to said first chamber to cycle said first piston between said first position and said second position at said predetermined duty cycle while maintaining said second piston in said first position. 
     
     
         18 . The compressor of  claim 16 , wherein said valve assembly supplies said pressurized fluid to said first chamber to cycle said first piston between said first position and said second position at said predetermined duty cycle while maintaining said second piston in said second position. 
     
     
         19 . A compressor comprising:
 a first compression mechanism;   a first valve plate associated with said first compression mechanism and including a first port;   a first manifold disposed adjacent to said first valve plate and including a first cylinder having a first piston disposed therein, said first piston movable relative to said first manifold between a first position separated from said first valve plate opening said first port and a second position contacting said first valve plate closing said first port;   a second compression mechanism;   a second valve plate associated with said second compression mechanism and including a second port;   a second manifold disposed adjacent to said second valve plate and including a second cylinder having a second piston disposed therein, said second piston movable relative to said second manifold between a first position separated from said second valve plate opening said second port and a second position contacting said second valve plate closing said second port; and   a valve assembly operable to modulate a capacity of the compressor by moving said first piston and said second piston between said first position and said second position, said valve assembly moving said first piston between said first position and said second position using a first capacity modulation method and moving said second piston between said first position and said second position using a second capacity modulation method independent from said first capacity modulation method.   
     
     
         20 . The compressor of  claim 19 , wherein said valve assembly includes a first solenoid valve associated with said first piston and a second solenoid valve associated with said second piston. 
     
     
         21 . The compressor of  claim 19 , wherein said first piston includes a first valve element disposed therein and movable relative to said first piston and said second piston includes a second valve element disposed therein and movable relative to said second piston, said first valve element and said second valve element respectively contacting said first valve plate and said second valve plate when said first piston and said second piston are in said second position. 
     
     
         22 . The compressor of  claim 21 , wherein said first piston and said second piston each include an inner volume having a pressurized fluid disposed therein, said pressurized fluid operable to bias said valve elements toward respective ends of said first piston and said second piston. 
     
     
         23 . The compressor of  claim 19 , further comprising a first chamber disposed between a top surface of said first piston and an inner surface of said first cylinder and a second chamber disposed between a top surface of said second piston and an inner surface of said second cylinder, said first chamber and said second chamber selectively receiving a pressurized fluid to move said first piston and said second piston from said first position to said second position. 
     
     
         24 . The compressor of  claim 23 , wherein said valve assembly selectively supplies said pressurized fluid to said first chamber and said second chamber. 
     
     
         25 . The compressor of  claim 24 , wherein said first capacity modulation method includes said valve assembly supplying said pressurized fluid to said first chamber to cycle said first piston between said first position and said second position at a predetermined duty cycle and said second capacity modulation method includes maintaining said second piston in said first position. 
     
     
         26 . The compressor of  claim 24 , wherein said first capacity modulation method includes said valve assembly supplying said pressurized fluid to said first chamber to cycle said first piston between said first position and said second position at a predetermined duty cycle and said second capacity modulation method includes maintaining said second piston in said second position. 
     
     
         27 . The compressor of  claim 19 , wherein said first capacity modulation method includes cycling said first piston between said first position and said second position at a predetermined duty cycle and said second capacity modulation method includes maintaining said second piston in said first position. 
     
     
         28 . The compressor of  claim 19 , wherein said first capacity modulation method includes cycling said first piston between said first position and said second position at a predetermined duty cycle and said second capacity modulation method includes maintaining said second piston in said second position.