Compressor having capacity modulation assembly

1. A compressor comprising:

a shell assembly defining a suction pressure region and a discharge pressure region;

a first scroll member disposed within said shell assembly and including a first end plate having a discharge passage, a first spiral wrap extending from said first end plate and a biasing passage extending through said first end plate;

a second scroll member disposed within said shell assembly and including a second end plate having a second spiral wrap extending therefrom, said first and second spiral wraps meshingly engaged with each other and forming a series of pockets therebetween;

a seal assembly engaging said first scroll member and isolating said discharge pressure region from said suction pressure region, said seal assembly and said first scroll member defining an axial biasing chamber therebetween, said biasing passage being in communication with a first of said pockets and said axial biasing chamber;

a modulation control chamber fluidly coupled with said axial biasing chamber by a first passage; and

a modulation control valve fluidly coupled with said modulation control chamber by a second passage and movable between a first position allowing communication between said second passage and said suction pressure region and a second position restricting communication between said second passage and said suction pressure region.

2. The compressor of claim 1 , wherein said seal assembly engages an annular hub of said first scroll member and said modulation chamber is an annular chamber extending around said hub.

3. The compressor of claim 1 , wherein said biasing passage communicates intermediate pressure fluid from said first of said pockets to said axial biasing chamber, said intermediate pressure fluid is at a pressure between a pressure of said suction pressure region and a pressure of said discharge pressure region.

4. The compressor of claim 1 , further comprising a modulation valve ring located axially between said seal assembly and said first end plate and engaging an outer radial surface of an annular hub extending from said first end plate, said modulation valve ring partially defining said axial biasing chamber and said modulation control chamber.

5. The compressor of claim 4 , wherein said seal assembly is disposed radially between said modulation valve ring and an annular hub of said first scroll member.

6. The compressor of claim 4 , further comprising a modulation lift ring cooperating with said modulation valve ring to define said modulation control chamber therebetween, wherein said modulation valve ring extends axially beyond and radially inward relative to said modulation lift ring and said modulation lift ring defines an axial stop for said modulation valve ring.

7. The compressor of claim 6 , wherein said modulation lift ring is disposed axially between said first end plate and said modulation valve ring.

8. The compressor of claim 1 , wherein said first passage defines a greater flow restriction than said second passage.

9. A compressor comprising:

a shell assembly defining a suction pressure region and a discharge pressure region;

a first scroll member disposed within said shell assembly and including a first end plate having a discharge passage, a first spiral wrap extending from said first end plate and a biasing passage extending through said first end plate;

a second scroll member disposed within said shell assembly and including a second end plate having a second spiral wrap extending therefrom, said first and second spiral wraps meshingly engaged with each other and forming a series of pockets therebetween;

a seal assembly engaging said first scroll member and isolating said discharge pressure region from said suction pressure region, said seal assembly and said first scroll member defining an axial biasing chamber therebetween, said biasing passage being in communication with a first of said pockets and said axial biasing chamber;

a modulation control chamber fluidly coupled with said axial biasing chamber; and

a modulation control valve fluidly coupled with said modulation control chamber and movable between a first position allowing communication fluid to flow from said axial biasing chamber and into said suction pressure region via said modulation control chamber and a second position restricting communication between said axial biasing chamber and said suction pressure region.

10. The compressor of claim 9 , wherein said modulation control chamber is fluidly coupled with said axial biasing chamber by a first passage, and said modulation control valve is fluidly coupled with said modulation control chamber by a second passage.

11. The compressor of claim 10 , wherein said first passage defines a greater flow restriction than said second passage.

12. The compressor of claim 9 , wherein said modulation control valve is disposed along a first passage extending between said axial biasing chamber and said modulation control chamber.

13. The compressor of claim 12 , wherein said modulation control valve is in communication with said suction pressure region by a second passage.

14. The compressor of claim 13 , wherein said second passage defines a greater flow restriction than said first passage.

15. The compressor of claim 9 , wherein said seal assembly engages an annular hub of said first scroll member and said modulation chamber is an annular chamber extending around said hub.

16. The compressor of claim 9 , wherein said biasing passage communicates intermediate pressure fluid from said first of said pockets to said axial biasing chamber, said intermediate pressure fluid is at a pressure between a pressure of said suction pressure region and a pressure of said discharge pressure region.

17. The compressor of claim 9 , further comprising a modulation valve ring located axially between said seal assembly and said first end plate and engaging an outer radial surface of an annular hub extending from said first end plate, said modulation valve ring partially defining said axial biasing chamber and said modulation control chamber.

18. The compressor of claim 17 , further comprising a modulation lift ring cooperating with said modulation valve ring to define said modulation control chamber therebetween, wherein said modulation valve ring extends axially beyond and radially inward relative to said modulation lift ring and said modulation lift ring defines an axial stop for said modulation valve ring.

19. The compressor of claim 18 , wherein said modulation lift ring is disposed axially between said first end plate and said modulation valve ring.

20. The compressor of claim 19 , wherein said seal assembly is disposed radially between said modulation valve ring and an annular hub of said first scroll member.