Compressor having output adjustment assembly including piston actuation

1. A compressor comprising:

a housing;

a first scroll member supported within said housing and including a first end plate, a first spiral wrap extending from a first side of said first end plate, a first chamber located on a second side of said first end plate having first and second passages in communication therewith, a second chamber located on said second side of said first end plate having third and fourth passages in communication therewith, said first and third passages being in communication with a first pressure source and said second and fourth passages being selectively in communication with a second pressure source, a first aperture extending through said first end plate and in communication with said first chamber, and a second aperture extending through said first end plate and in communication with said second chamber;

a second scroll member supported within said housing and including a second end plate having a second spiral wrap extending therefrom and meshingly engaged with said first spiral wrap to form a series of pockets, said first aperture being in communication with a first of said pockets operating at a first pressure to provide communication between said first pocket and said first chamber and said second aperture being in communication with a second of said pockets different from said first pocket and operating at a second pressure to provide communication between said second pocket and said second chamber; and

a compressor output adjustment assembly including first and second pistons, said first piston located in said first chamber and displaceable between first and second positions and said second piston located in said second chamber and displaceable between first and second positions, said first piston isolating said first aperture from communication with said first passage when in its second position and said second piston isolating said second aperture from communication with said third passage when in its second position.

2. The compressor of claim 1 , wherein said first piston is in its second position when said second piston is in its second position.

3. The compressor of claim 1 , further comprising a valve assembly operable in first and second modes and in communication with said second pressure source and said second and fourth passages, said valve assembly providing communication between said second and fourth passages and said second pressure source during the first operating mode.

4. The compressor of claim 3 , wherein said valve assembly is in communication with a suction pressure region of the compressor and provides communication between said second and fourth passages and said suction pressure region and isolates said second and fourth passages from communication with said second pressure source during the second operating mode.

5. The compressor of claim 3 , wherein said second pressure source includes a discharge pressure region of the compressor.

6. The compressor of claim 5 , wherein said first scroll member includes a discharge passage in communication with said discharge pressure region and a fifth passage in communication with said discharge passage and said valve assembly.

7. The compressor of claim 6 , wherein said first piston is in its second position when said second passage is in communication with said second pressure source.

8. The compressor of claim 7 , wherein said second piston is in its second position when said fourth passage is in communication with said second pressure source.

9. The compressor of claim 6 , wherein said first piston is in its first position when said second passage is isolated from said second pressure source.

10. The compressor of claim 9 , wherein said first piston is in its first position when said second passage is in communication with a suction pressure region of the compressor.

11. The compressor of claim 1 , further comprising a floating seal, said floating seal engaged with said first scroll member to form a third chamber.

12. The compressor of claim 11 , wherein said first and second chambers are located axially between said third chamber and said pockets.

13. The compressor of claim 11 , wherein said third chamber is isolated from communication with said first and second chambers.

14. The compressor of claim 1 , wherein each of said first and second pressures are at an intermediate pressure between an operating pressure of a suction pressure region of the compressor and an operating pressure of said second pressure source.

15. The compressor of claim 1 , wherein said first and second chambers are rotationally spaced from one another.

16. The compressor of claim 1 , wherein said compressor output adjustment assembly includes a first biasing member engaged with said first piston to bias said first piston to its first position and a second biasing member engaged with said second piston to bias said second piston to its first position.

17. The compressor of claim 16 , wherein said first and second apertures are in communication with a suction pressure region of the compressor when said first piston is in its first position and said second piston is in its first position.

18. The compressor of claim 1 , wherein said compressor output adjustment assembly includes a vapor injection system in communication with said first and third passages.

19. The compressor of claim 18 , wherein said vapor injection system is in communication with said first and second apertures when said first piston is in its first position and said second piston is in its first position.

20. The compressor of claim 1 , wherein said first piston is axially displaceable between its first and second positions and said second piston is axially displaceable between its first and second positions.