Compressor Having Capacity Modulation System

Abstract

A compressor may include first and second scrolls and a capacity-modulation system. The first and second scrolls include first and second end plates and first and second spiral wraps. The second end plate may define a suction inlet, a discharge passage, a modulation port, and a vent passage. The capacity-modulation system may include a control valve and a piston. The control valve is movable between first and second positions. The piston may be disposed within a recess in the second end plate and is movable between an open position in which communication between the modulation port and the vent passage is allowed and a closed position in which communication between the modulation port and the vent passage is prevented. Moving the control valve to the first position moves the piston to the closed position. Moving the control valve to the second position moves the piston to the open position.

What is claimed is: 
     
         1 . A compressor comprising:
 a first scroll having a first end plate and a first spiral wrap extending from the first end plate;   a second scroll having a second end plate and a second spiral wrap extending from the second end plate, wherein the first and second spiral wraps cooperate to define a plurality of fluid pockets; and   a control valve including a body, a housing, and a valve member, wherein:
 the body is fixedly received in a valve passage in the second end plate and sealingly engages a first portion of the valve passage, 
 the body includes a first passage, a second passage, and a third passage, 
 the housing is fixed relative to the second end plate and the body and includes an aperture that is open to a suction chamber of the compressor, 
 the valve member is disposed within the housing and is movable therein between first and second positions, 
 the valve member includes a stem portion that is movably received in the first passage of the body, 
 when the valve member is in the first position, the stem portion allows fluid communication between the second and third passages and prevents fluid communication between the third passage and the aperture in the housing, and 
 when the valve member is in the second position, the stem portion prevents fluid communication between the second and third passages and allows fluid communication between the third passage and the aperture in the housing. 
   
     
     
         2 . The compressor of  claim 1 , wherein:
 the control valve includes a solenoid coil and a spring,   the spring biases the valve member toward the second position, and   when the solenoid coil is energized, the valve member moves toward the first position.   
     
     
         3 . The compressor of  claim 1 , wherein a chamber is formed between an outer diametrical surface of the body of the control valve and a diametrical surface of a second portion of the valve passage in the second end plate, wherein the chamber is in fluid communication with another passage in the second end plate that extends away from the control valve. 
     
     
         4 . The compressor of  claim 3 , wherein the valve passage is in fluid communication with a source of working fluid that is at a pressure higher than suction pressure. 
     
     
         5 . The compressor of  claim 4 , wherein the source of working fluid is a source of intermediate-pressure working fluid defined by the second end plate, and wherein the second passage in the body of the control valve receives intermediate-pressure working fluid from the source of intermediate-pressure working fluid defined by the second end plate. 
     
     
         6 . The compressor of  claim 5 , wherein the third passage of the control valve receives the intermediate-pressure working fluid from the second passage when the valve member is in the first position. 
     
     
         7 . The compressor of  claim 6 , wherein the third passage of the control valve contains suction-pressure working fluid and is vented to the first passage of the control valve and the aperture in the housing when the valve member is in the second position. 
     
     
         8 . The compressor of  claim 7 , wherein the source of intermediate-pressure working fluid is an axial biasing chamber defined by the second end plate and a floating seal assembly. 
     
     
         9 . The compressor of  claim 7 , wherein during operation of the compressor, the fluid pockets move from a radially outer position to radially intermediate positions to a radially inner position, and wherein the source of intermediate-pressure working fluid is one of the fluid pockets at one of the radially intermediate positions. 
     
     
         10 . The compressor of  claim 7 , wherein working fluid is allowed to flow through a gap around the stem portion within the first passage of the body of the control valve when the valve member is in the second position. 
     
     
         11 . A compressor comprising:
 a first scroll having a first end plate and a first spiral wrap extending from the first end plate;   a second scroll having a second end plate and a second spiral wrap extending from the second end plate, wherein the first and second spiral wraps cooperate to define a plurality of fluid pockets;   a capacity-modulation system configured to switch the compressor between a high-capacity mode and a low-capacity mode; and   a control valve configured to actuate the capacity-modulation system, the control valve including a body, a housing, and a valve member,   wherein:
 the body is fixedly received in a valve passage in the second end plate and sealingly engages a first portion of the valve passage, 
 the body includes a first passage, a second passage, and a third passage, 
 the housing is fixed relative to the second end plate and the body and includes an aperture that is open to a suction chamber of the compressor, 
 the valve member is disposed within the housing and is movable therein between first and second positions, 
 the valve member includes a stem portion that is movably received in the first passage of the body, 
 when the valve member is in the first position, the stem portion allows fluid communication between the second and third passages and prevents fluid communication between the third passage and the aperture in the housing, 
 when the valve member is in the second position, the stem portion prevents fluid communication between the second and third passages and allows fluid communication between the third passage and the aperture in the housing, 
 movement of the valve member to the first position causes the capacity-modulation system to switch the compressor to the high-capacity mode, and 
 movement of the valve member to the second position causes the capacity-modulation system to switch the compressor to the low-capacity mode. 
   
     
     
         12 . The compressor of  claim 11 , wherein:
 the control valve includes a solenoid coil and a spring,   the spring biases the valve member toward the second position, and   when the solenoid coil is energized, the valve member moves toward the first position.   
     
     
         13 . The compressor of  claim 11 , wherein a chamber is formed between an outer diametrical surface of the body of the control valve and a diametrical surface of a second portion of the valve passage in the second end plate. 
     
     
         14 . The compressor of  claim 13 , wherein the chamber is in fluid communication with another passage in the second end plate that extends away from the control valve. 
     
     
         15 . The compressor of  claim 14 , wherein the valve passage is in fluid communication with a source of working fluid that is at a pressure higher than suction pressure. 
     
     
         16 . The compressor of  claim 15 , wherein the source of working fluid is a source of intermediate-pressure working fluid defined by the second end plate. 
     
     
         17 . The compressor of  claim 16 , wherein the second passage in the body of the control valve receives intermediate-pressure working fluid from the source of intermediate-pressure working fluid defined by the second end plate, and wherein the third passage of the control valve receives the intermediate-pressure working fluid from the second passage when the valve member is in the first position. 
     
     
         18 . The compressor of  claim 17 , wherein the third passage of the control valve contains suction-pressure working fluid and is vented to the first passage of the control valve and the aperture in the housing when the valve member is in the second position. 
     
     
         19 . The compressor of  claim 18 , wherein the source of intermediate-pressure working fluid is an axial biasing chamber defined by the second end plate and a floating seal assembly. 
     
     
         20 . The compressor of  claim 18 , wherein working fluid is allowed to flow through a gap around the stem portion within the first passage of the body of the control valve when the valve member is in the second position.