Patent ID: 7976295

Claim:
A compressor comprising: a housing; a first scroll member supported within said housing and including a first end plate having a discharge passage, 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, a first passage extending through said end plate and in communication with said first chamber and said discharge passage, a second passage extending through said end plate from said first chamber to an outer surface of said first scroll member, a third passage extending through said end plate from said first chamber to a suction pressure region of the compressor, and a first aperture extending through said first end plate and in communication with said first 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 to provide communication between said first pocket and said first chamber; a piston located within said first chamber and axially displaceable between first and second positions, said piston isolating said first and second passages from communication with said first aperture and said third passage when in the first and second positions, said piston preventing communication between said first aperture and said third passage when in the first position, and said piston providing communication between said first aperture and said third passage when in the second position; and a valve assembly in communication with said second passage to selectively vent said second passage to the suction pressure region of the compressor and displace said piston between the first and second positions.