moving volute this closing off of the end of the bore 37 directed towards the moving volute 9 not only lubricates the interface between the body 5 and the moving volute but also regulates the amount of oil injected into the compression volume when the speed of the compressor exceeds the predetermined value the control means move the core 34 of the solenoid valve to its open position as a result all or nearly all the oil entering the solenoid valve through the oil inlet port 27 is directed to the first oil outlet port 29 because head losses in the second oil outlet orifice 30 and in the first and second injection pipes 31 32 are much greater than those in the first oil outlet port 29 as a result all or nearly all the oil that has entered the solenoid valve falls by gravity into the oil sump 22 the compressor according to the invention allows the amount of oil present in the compression volume and therefore the proportion of oil in the refrigerant gas to be increased only when the speed of the compressor is low and below the predetermined threshold value the present invention improves the low speed performance of the variable speed compressor without reducing its efficiency at high speed in another embodiment of the invention shown in fig4 and 5 the solenoid valve 25 has a pipe 40 connecting the second outlet port 30 to a connection port 41 formed in the second body portion 26 b the connection port 41 leads into the bottom of the bore 35 containing the core 34 of the solenoid valve the.