A scroll compressor includes a fluid injection system. The fluid injection
system includes a fluid passage which extends from a position outside of
the shell of the compressor to the fluid pockets created by the wraps of
the scroll members. The fluid passage extends through the orbiting scroll
member. The fluid injection system can be used to inject gaseous or
liquid refrigerant, lubricant or the fluid injection system can be used
to vent the moving pocket to the suction area of the compressor for
capacity modulation.