Patent ID: 8277200
Filing Date: 2012-10-02
Classification: F04B

Abstract:
1. A variable displacement compressor comprising: a suction valve capable of generating a noise when the compressor is operating at low displacement; a suction shutoff valve (SSV) for providing a variable restriction of fluid communication with the suction valve to prevent the noise from propagating out of the compressor, said variable restriction influenced by a regulated pressure; a regulator valve that determines the regulated pressure by controlling fluid communication with a discharge pressure, wherein said regulator valve cooperates with the SSV for increasing the variable restriction when the discharge pressure is indicative of the compressor operating at low displacement for preventing the noise from propagating out of the compressor, and decreasing the variable restriction when the discharge pressure is indicative of the compressor operating at high displacement for improving compressor efficiency at high displacement, wherein the regulator valve is also in fluid communication with an internal suction pressure, whereby if a pressure difference of the discharge pressure minus the internal suction pressure is less than a first threshold, then the discharge pressure is indicative of the compressor operating at low displacement, and if the pressure difference of discharge pressure minus the internal suction pressure is greater than the first threshold, then the discharge pressure is indicative of the compressor operating at high displacement, wherein the suction valve is located in an internal suction region containing refrigerant at the internal suction pressure received from an external suction region containing refrigerant at an external suction pressure, and the variable restriction provided by the SSV variably restricts fluid communication between the internal suction region and the external suction region, a housing separating the internal suction region and the external suction region and defining an opening for fluid communication between the internal suction region and the external suction region; a piston sliding sealingly within the housing, said piston having a piston position relative to the opening for variably obstructing the opening to vary the variable restriction; and a regulated region defined at least in part by the piston and the housing, said regulated region containing refrigerant at a regulated pressure, and said regulated pressure being influenced by the regulator valve, wherein the piston position is biased by the regulated pressure towards obstructing the opening, thereby increasing the variable restriction, wherein the regulator valve comprises a restricted orifice for providing restricted fluid communication between the internal suction region and the regulated region; a valve body having an outlet orifice for providing fluid communication between the regulated region and a discharge region containing refrigerant at the discharge pressure; a valve member arranged within the valve body, said valve member having a valve member position relative to the outlet orifice for variably obstructing the outlet orifice and thereby influencing the regulated pressure by variably restricting fluid communication between the regulated region and the discharge region; and a regulator spring for biasing the regulator valve such that the outlet orifice is not obstructed if the pressure difference is less the first threshold, and the outlet orifice is obstructed if the pressure difference is greater than the first threshold, wherein the restricted orifice, the outlet orifice and the spring are proportionately sized such that the regulated pressure is biased toward the discharge pressure if the pressure difference less than the first threshold, and the regulated pressure is biased toward the internal suction pressure if the pressure difference is greater than the first threshold, wherein the regulator valve fluid communication with the discharge region is through an inlet orifice and the regulator valve is further configured to block fluid communication between the discharge region and the regulated region if the pressure difference is less than a second threshold that is less than the first threshold, wherein the pressure difference being below the second threshold indicates that the compressor is not being operated for discharging refrigerant.