Patent ID: 9027358
Filing Date: 2015-05-12
Classification: B60H,F25B

Abstract:
1. A vehicle heat pump system comprising: a compressor including an inlet side and an outlet side; a first valve fluidly coupled to the outlet side of the compressor to receive compressed refrigerant exiting the outlet side of the compressor; a cooling circuit being fluidly coupled between the first valve and the inlet side of the compressor; a heating circuit fluidly coupled between the first valve and the inlet side of the compressor, the heating circuit including a heating circuit evaporator, the heating circuit further including a second valve located between the heating circuit evaporator and the inlet side of the compressor, the first valve being configured to switch direction of flow of compressed refrigerant exiting the compressor between flowing to the cooling circuit establishing a cooling mode and flowing to the heating circuit establishing a heating mode, the second valve being configured to switch between an open state and a closed state such that in the open state refrigerant within the heating circuit flows to the inlet side of the compressor and in the closed state refrigerant within the heating circuit is prevented from flowing to the inlet side of the compressor; and a controller operatively coupled to the first and second valves, the controller being configured to switch the first valve to block refrigerant flow to the heating circuit and direct refrigerant flow to the cooling circuit to establish the cooling mode, the controller being configured to switch the first valve to block refrigerant flow to the cooling circuit and direct refrigerant flow to the heating circuit to establish the heating mode, and the controller being further configured such that while operating in the heating mode the controller cycles the second valve between the open state where refrigerant flows from the heating circuit to the inlet of the compressor and the closed state where the second valve blocks refrigerant flow from the heating circuit to the inlet side of the compressor, such that with the second valve in the closed state the compressor draws refrigerant out of the cooling circuit and refrigerant pressure builds up within the heating circuit, and the controller being further configured to maintain the second valve in the open state upon the controller determining that sufficient refrigerant has been drawn out of the cooling circuit during the cycling of the second valve while operating in the heating mode.