Abstract: In an ejector cycle having an ejector, a decompression amount of refrigerant between a gas-liquid separator and an evaporator is adjusted by a differential pressure control valve, so that a pressure increasing amount in a pressure increasing portion of the ejector is controlled to be equal to or lower than a predetermined amount. Therefore, a suction pressure of refrigerant to be sucked to the compressor can be restricted from being excessively increased in accordance with the increase of the pressure increasing amount in the ejector, and it can prevent heat radiating capacity of a radiator from being decreased. Thus, a sufficient cooling capacity can be always obtained in the ejector cycle.

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 vapor compression refrigeration system, an evaporator and a gas-liquid separator are received in a common casing, so that the gas-liquid separator and the evaporator are placed close to each other. Thus, it is possible to limit heat absorption of the liquid phase refrigerant from the atmosphere to reduce the heat loss upon discharge of the refrigerant from the gas-liquid separator. Also, it is possible to reduce pressure loss in a refrigerant passage between the gas-liquid separator and the evaporator.

Abstract: In an ejector, a nozzle includes a nozzle tapered section having an inner passage with a radial dimension reduced toward a nozzle outlet port, and a needle having a needle tapered section disposed in the inner passage. The needle tapered section has a cross sectional area reduced toward a downstream end of the needle, and the downstream end of the needle is positioned at a downstream side with respect to the nozzle outlet port. In addition, the nozzle tapered section has a taper angle (&phgr;1) which is equal to or greater than a taper angle (&phgr;2) of the needle tapered section. Therefore, a boundary face on the outside of a nozzle jet flow becomes in a balanced natural shape, and is controlled in accordance with an operating condition. Thus, the ejector cycle can be operated while keeping high efficiency, regardless of the thermal load of the ejector cycle.

Abstract: In a vapor-compression refrigerant cycle having an ejector, a mixture refrigerant of a first refrigerant and a second refrigerant is used. When the mixture refrigerant is decompressed and expanded in a nozzle of the ejector, the first refrigerant has an adiabatic heat drop that is larger than that of the second refrigerant. Further, the second refrigerant has an evaporation latent heat that is larger than that of the first refrigerant. In a gas-liquid separator, a gas-phase amount of the first refrigerant is made larger than that of the second refrigerant, and a liquid-phase amount of the second refrigerant is made larger than that of the first refrigerant. For example, the first refrigerant is propane, and the second refrigerant is butane. Accordingly, expansion energy recovered in the nozzle can be effectively converted to pressure energy in a pressure increasing portion of the ejector while cooling capacity of an evaporator can be improved.

Abstract: In a gas-liquid separator for an ejector cycle, a tank body is constructed such that a refrigerant sprayed from a refrigerant inlet forms a spiral stream in the tank body. The tank body has a horizontal longitudinal axis greater than a vertical axis. The refrigerant inlet is located at a distance from the horizontal longitudinal axis of the tank body such that the refrigerant sprayed from the refrigerant inlet generates a turning force and spirally flows. With this, a gas-liquid separation distance of the refrigerant increases.

Abstract: An ejector for a refrigerant cycle includes a nozzle having therein a refrigerant passage, and a needle valve provided in the refrigerant passage of the nozzle upstream from a throat portion of the nozzle. The needle valve is disposed in the nozzle to define therebetween a throttle portion that is positioned upstream from the throat portion. A top end portion of the needle valve and an inner wall of the nozzle are formed, so that refrigerant is decompressed to a gas-liquid two-phase state at upstream of the throat portion. Accordingly, a throttle degree of the nozzle can be variably controlled while ejector efficiency is not deteriorated.

Abstract: An air conditioner with an ejector includes first and second interior heat exchangers for performing heat-exchange between refrigerant and air to be blown into a compartment. The second interior heat exchanger is disposed at a downstream air side of the first interior heat exchanger, and a decompression valve for decompressing refrigerant in a dehumidifying-heating operation is disposed in a refrigerant passage connecting the first and second interior heat exchangers. In a cooling operation, the first and second interior heat exchanger are used as evaporators. On the other hand, in the dehumidifying-heating operation, refrigerant decompressed in the decompression valve is evaporated in the first interior heat exchanger while bypassing a nozzle of the ejector, and refrigerant is radiated in the second interior heat exchanger.

Abstract: In an ejector cycle system, a variable throttle is disposed at an upstream side of an ejector. When high-pressure side refrigerant pressure in the ejector cycle system is approximately equal to or higher than critical pressure of the refrigerant, the variable throttle is fully opened. When the high-pressure side refrigerant pressure is approximately lower than the critical pressure of the refrigerant, a throttle open degree of the variable throttle is reduced from the fully open degree so that high-pressure side refrigerant is decompressed in two steps of the variable throttle and the ejector. Accordingly, in both cases of a high heat load and a low heat load of the ejector cycle system, COP of the ejector cycle system can be improved.

Abstract: When an air conditioning heat load is equal to or greater than a predetermined value, the degree of throttle opening of a nozzle arrangement of an ejector is controlled in such a manner that a coefficient of performance coincides with a target value. When the air conditioning heat load is less than the predetermined value, the degree of throttle opening of the nozzle arrangement is controlled in such a manner that a flow rate of refrigerant, which passes through the nozzle arrangement, coincides with a target value.

Abstract: In a vapor compression refrigeration system, an evaporator and a gas-liquid separator are received in a common casing, so that the gas-liquid separator and the evaporator are placed close to each other. Thus, it is possible to limit heat absorption of the liquid phase refrigerant from the atmosphere to reduce the heat loss upon discharge of the refrigerant from the gas-liquid separator. Also, it is possible to reduce pressure loss in a refrigerant passage between the gas-liquid separator and the evaporator.

Abstract: An ejector includes a nozzle having therein a throat portion, and a needle valve that extends at least from the throat portion to the outlet of the nozzle. The needle valve is displaced in an axial direction of the nozzle to adjust an opening degree of the throat portion and an opening degree of an outlet of the nozzle. Therefore, even when a flow amount of refrigerant flowing into the nozzle is changed, it can prevent a vertical shock wave from being generated by suitably adjusting both the opening degrees of the throat portion and the opening degree of the outlet of the nozzle. Accordingly, nozzle efficiency can be improved regardless of a change of the flow amount of the refrigerant.

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.

Abstract: In a refrigerant cycle system with an ejector pump, refrigerant to be introduced into a nozzle of the ejector pump is heated in a heat exchanger using waste heat from a vehicle engine as a heating source, and any one of a first mode, a second mode and a third mode can be selectively set based on a thermal load of an evaporator. In the first mode, refrigerant circulates from the evaporator toward a radiator only by the ejector pump. In the second mode, refrigerant circulate from the evaporator toward the radiator only by a compressor. Further, in the third mode, refrigerant circulates from the evaporator toward the radiator by using both the ejector pump and the compressor. Accordingly, the waste heat can be effectively recovered while a flow resistance of the refrigerant can be restricted.

Abstract: In an ejector cycle having an ejector for decompressing refrigerant, a check valve is disposed in an oil return passage through which refrigerant including a lubrication oil is introduced from a refrigerant outlet side of an evaporator to a refrigerant suction side of a compressor while bypassing the ejector. When the lubrication oil amount staying in the evaporator reduces, the check valve is automatically closed, and a normal operation mode of the ejector cycle is automatically set. On the contrary, when a large amount of lubrication oil stays in the evaporator, the check valve is automatically opened, and an oil return mode is automatically set. Therefore, the lubrication oil staying in the evaporator can be controlled equal to or lower than a predetermined amount, thereby effectively returning the lubrication oil to the compressor.

Abstract: In an ejector-type depressurizer, a nozzle arrangement converts pressure energy of refrigerant supplied from a radiator into velocity energy to depressurize and expand the refrigerant, and a pressurizer arrangement mixes the refrigerant discharged from the nozzle arrangement with the refrigerant drawn from an evaporator and converts the velocity energy of the refrigerant discharged from the nozzle arrangement into pressure energy to increase the pressure of the mixed refrigerant discharged from the pressurizer arrangement. The pressurizer arrangement includes a refrigerant passage that conducts the refrigerant supplied from the nozzle arrangement and the refrigerant supplied from the evaporator, and the refrigerant passage includes a refrigerant passing zone, through which the refrigerant from the nozzle arrangement and the refrigerant from the evaporator mainly pass during operation of the ejector-type depressurizer.

Abstract: A nozzle (41) is made of a sintered metal, and a pressure increasing portion (a mixing portion (42) and a diffuser (43)) is manufactured by plastic-forming a metal pipe. Accordingly, the nozzle (41) can be manufactured in a short time while high accuracy in machining is maintained. Thus, the cost of manufacturing an ejector (40) can be reduced.

Abstract: Piping, which connects between a radiator and an ejector, is covered with a thermal insulator to thermally insulate a refrigerant passage defined in the piping. Thus, it is possible to limit a reduction in enthalpy of refrigerant, which could be induced by cooling of high temperature refrigerant by low temperature atmosphere to lose the enthalpy before depressurization of the high temperature refrigerant through the ejector. As a result, it is possible to limit a reduction in a theoretical value of recoverable energy at the time of depressurization and expansion of the refrigerant.

Abstract: An air conditioner includes a compressor for compressing refrigerant, an exterior heat exchanger for performing heat exchange between refrigerant and outside air, an interior heat exchanger for performing heat exchange between the refrigerant and air to be blown into the compartment, an ejector for decompressing high-pressure refrigerant, a heater core for heating air using a high-temperature fluid as a heating source, and a fluid-refrigerant heat exchanger that heats the fluid flowing to the heater core using high-temperature refrigerant discharged from the compressor as a heating source. In a dehumidifying and heating operation, refrigerant in the interior heat exchanger absorbs heat from air so that the air is cooled and dehumidified, and the dehumidified and cooled air can be further heated in the heater core by indirectly using the heating source from the high-temperature refrigerant.

Abstract: An air conditioner includes a compressor for compressing refrigerant, an exterior heat exchanger for performing heat exchange between refrigerant and outside air, an interior heat exchanger for performing heat exchange between the refrigerant and air to be blown into the compartment, a decompression unit for decompressing high-pressure refrigerant, and a heater that heats air using high-temperature refrigerant discharged from the compressor as a heating source. In a dehumidifying and heating operation, refrigerant in the interior heat exchanger absorbs heat from air so that the air is cooled and dehumidified, and the heater heats air having been dehumidified and cooled by using the heating source, so that low-humidity and high-temperature air is supplied into the compartment. The heater can be disposed to indirectly heat air by heating a fluid flowing through a heater core for heating air, or to directly heat air to be blown into the compartment.