Abstract: In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, a control unit controls an air blowing amount of an evaporator fan so that a flow speed of refrigerant flowing in an evaporator becomes in a predetermined flow speed range. Therefore, it can prevent a large amount of lubrication oil from staying in the evaporator, and thereby the lubrication oil can sufficiently returns to a compressor. For example, the control unit includes a determining means for determining the predetermined flow speed range based on at least one of an atmosphere temperature of a condenser, a temperature of air supplied to the evaporator and a flow amount of refrigerant discharged from the compressor.

Abstract: In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, a refrigerant outlet is provided in an evaporator at a position upper than a refrigerant inlet. Therefore, a circulation performance of refrigerant flowing in the evaporator can be improved. Accordingly, even when a pumping capacity generated in the ejector becomes smaller, a sufficient amount of refrigerant can be drawn into the ejector from the evaporator. Thus, a refrigerant amount supplied to the evaporator can be effectively increased. Further, a control unit controls an amount of cooling air supplied to a condenser based on the temperature of the cooling air, to control a refrigerant state to be introduced to the nozzle. In this case, a pressure increasing amount in the ejector can be effectively increased, and consumption power in the compressor can be effectively increased.

Abstract: In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, a receiver for storing refrigerant therein is disposed at a refrigerant outlet side of a condenser. Further, a bypass passage and a switching valve for opening and closing the bypass passage are provided so that high-temperature refrigerant discharged from a compressor is introduced into an evaporator while bypassing the condenser in a defrosting operation. When the defrosting operation is set, the switching valve is opened while a fan for blowing cool air to the condenser is operated. Accordingly, in the defrosting operation, at least a part of refrigerant discharged from the compressor flows into the evaporator to remove frost on a surface of the evaporator, and a surplus refrigerant is condensed in the condenser and is stored in the receiver. Accordingly, it can prevent condensation capacity of the condenser from being decreased.

Abstract: In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, a variable throttle device is disposed upstream from the nozzle to decompress and expand high-pressure refrigerant flowing from a condenser. For example, the variable throttle device decompresses the high-pressure refrigerant in a gas-liquid two-phase state at an upstream position from the nozzle of the ejector. In addition, the variable throttle device includes a back pressure chamber having an inner pressure that changes by sensing a refrigerant temperature at a refrigerant outlet side of an evaporator, and a pressure introducing means for introducing a refrigerant pressure of a refrigerant outlet side of the evaporator to a side opposite to the back pressure chamber with respect to a diaphragm. Therefore, a pressure difference between the back pressure chamber and the side opposite to the back pressure chamber can be made smaller.

Abstract: In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, an insulation member is provided on an outer surface of the ejector to suppress a heat exchange with an external side. When a suction portion of the ejector is insulated by the insulation member, pressure loss in the suction portion can be reduced, a gas refrigerant ratio at an inlet port of the mixing portion can be reduced, and a liquid refrigerant amount to be supplied to the evaporator can be increased. In addition, when a mixing portion and a diffuser portion of the ejector are insulated, it can prevent liquid refrigerant from being excessively evaporated. As a result, it can effectively restrict heat loss due to a heat exchange in the ejector with the external side.

Abstract: In an ejector, a nozzle is provided within a housing to defining a passage portion around the nozzle, and a suction port is provided in the housing to draw a refrigerant by entrainment of a driving refrigerant jetted from the nozzle. Further, a wall portion is provided in the housing such that the refrigerant drawn from the suction port into the passage portion is prevented from flowing toward an inlet side of the nozzle from a position of the suction port in an axial direction of the nozzle. Therefore, all of the refrigerant flowing from the suction port flows toward an outlet side of the nozzle without flowing toward the inlet side of the nozzle from the position of the suction port in the axial direction. Thus, it can prevent a large pressure loss from being caused in the refrigerant sucked from the suction port, and ejector efficiency can be effectively increased.

Abstract: In a heat exchanger for cooling air, a tube has a streamlined-shaped cross-section so that air flows along an outer surface of the tube without stagnating. Therefore, it is less likely that moisture contained in the air will adhere on the outer surface of the tube. Accordingly, the formation of frost is restricted.

Abstract: In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, a variable throttle is disposed upstream from the nozzle of the ejector to decompress and expand high-pressure refrigerant flowing from a radiator. For example, the variable throttle decompresses and expands the high-pressure refrigerant in a gas-liquid two-phase state at an upstream position from the nozzle of the ejector. The variable throttle controls a throttle opening degree so that a refrigerant super-heating degree at a refrigerant outlet side of an evaporator or at a refrigerant suction side of a compressor becomes in a predetermined range. Accordingly, the ejector cycle has an improved nozzle efficiency and an improved ejector efficiency in a wide load variation range of the ejector cycle.