EVAPORATOR UNIT

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2010-7965 filed on Jan. 18, 2010, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an evaporator unit for an ejector type refrigerating cycle.

2. Description of Related Art

A refrigerating cycle has an ejector as a refrigerant decompressor. Because the ejector has not only a refrigerant outlet but also a refrigerant suction port, it becomes complicated to connect the ejector to other devices of the refrigerating cycle, compared with a usual refrigerating cycle in which a decompressor has only the refrigerant outlet.

That is, it is not easy to mount the ejector type refrigerating cycle to a cooling or refrigerating device, compared with the usual refrigerating cycle. JP-B2-4259478 or JP-B2-3265649 discloses an evaporator unit, which is easily mounted to an ejector type refrigerating cycle, and the evaporator unit is produced by integrating an ejector and an evaporator.

JP-B2-4259478 discloses a tank-and-tube type heat exchanger as an evaporator. An ejector is integrated with the evaporator in a state that the ejector is arranged inside of a tank of the evaporator, or in a state that the ejector is arranged along a longitudinal direction of the tank. Thus, a size of the evaporator is made smaller as a whole unit.

JP-B2-3265649 discloses an evaporator unit having an ejector arranged adjacent to an evaporator. A refrigerant suction port of the ejector is connected to a refrigerant outlet of the evaporator by a suction side refrigerant pipe. Further, the suction side refrigerant pipe is made shorter, thereby lowering a pressure loss of refrigerant generated by the suction side refrigerant pipe. Thus, cycle efficiency is improved as a whole of ejector type refrigerating cycle.

When the ejector type refrigerating cycle is applied to a cooling or refrigerating device, for example, outer shapes of components constructing the cycle are required to be suitable for conditions of the device. When the ejector and the evaporator are integrated into the evaporator unit, an outer shape of the evaporator unit is required to be suitable for conditions of the device.

Therefore, a size of the evaporator is required to be made smaller. However, if a size of the tank of the evaporator is made smaller in JP-B2-4259478, the ejector cannot be arranged inside of the tank, or cannot be arranged along the longitudinal direction of the tank.

In contrast, if the evaporator unit is constructed by connecting the ejector and the evaporator by the refrigerant pipe, the outer shape of the evaporator unit is easily made suitable for conditions of the device.

However, a length of the refrigerant pipe cannot sufficiently be shortened by simply connecting the suction port of the ejector and the refrigerant outlet of the evaporator. In this case, the pressure loss of refrigerant generated by the refrigerant pipe may be increased. Thus, a refrigerant-drawing performance of the ejector may be lowered, and a refrigerating performance of the refrigerating cycle may be lowered.

SUMMARY OF THE INVENTION

In view of the foregoing and other problems, it is an object of the present invention to provide an evaporator unit.

According to an example of the present invention, an evaporator unit includes an ejector, an evaporator, and a refrigerant pipe. The ejector includes a nozzle to decompress refrigerant and a suction port to draw refrigerant using high-speed refrigerant flow injected from the nozzle. The evaporator evaporates refrigerant and discharges refrigerant toward the suction port of the ejector. The refrigerant pipe connects a refrigerant outlet of the evaporator and the suction port of the ejector. The ejector, the evaporator and the refrigerant pipe are integrated with each other into a unit, and the refrigerant outlet of the evaporator is located upper than the suction port of the ejector in a circumference direction of the refrigerant pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to a first embodiment;

FIG. 2 is view illustrating an ejector type refrigerating cycle having the evaporator unit;

FIG. 3A is a front view illustrating the evaporator unit, and FIG. 3B is a plan view illustrating the evaporator unit of FIG. 3A;

FIG. 4 is a perspective view illustrating the evaporator unit;

FIG. 5 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to a second embodiment;

FIG. 6 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to a third embodiment;

FIG. 7 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to a fourth embodiment;

FIG. 8 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to a fifth embodiment;

FIG. 9 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to a sixth embodiment;

FIG. 10 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to a seventh embodiment; and

FIG. 11 is a cross-sectional view illustrating an air-conditioner including an evaporator unit according to an eighth embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
First Embodiment

A first embodiment will be described with reference to FIGS. 1-4. An ejector type refrigerating cycle 20 having an evaporator unit 30 is applied to an air-conditioner of a vehicle, for example. An indoor unit of the air-conditioner has an air-conditioning unit 10, and the evaporator unit 30 is arranged in the air-conditioning unit 10, as shown in FIG. 1.

Up, down, front and rear arrow directions of FIG. 1 are defined in a state that the air-conditioning unit 10 is mounted in the vehicle. The indoor unit of the air-conditioner is arranged on an inner side of an instrument panel (not shown) ahead of a passenger compartment of the vehicle. The indoor unit is located on an inner side of a dash panel DP to separate an engine compartment from the passenger compartment, and is located on an inner side of a floor panel FP of the vehicle.

The indoor unit of the air-conditioner is constructed by the air-conditioning unit 10 of FIG. 1, and a blower unit (not shown) to send air to the air-conditioning unit 10. The air-conditioning unit 10 is arranged at approximately center section in a width direction of the vehicle. The blower unit is arranged on the inner side of the instrument panel, and is located offset from the center section toward a driver's seat.

The blower unit has an air inlet box (not shown) and a blower 27a of FIG. 2. The box switches air-introducing inlets between outside air and inside air. The blower 27a sends air into the passenger compartment from the box. The blower 27a is made of a centrifugal multi-blade fan such as sirocco fan, and is driven by an electric motor. A rotation number of the blower 27a is controlled by a control voltage output from an air-conditioning controller (not shown). Thus, an amount of air sent by the blower 27a is controlled.

As shown in FIG. 1, the air-conditioning unit 10 has a casing 11 to define an outer shape of the unit 10, and an air passage is defined in the casing 10. Air passes through the air passage toward the passenger compartment. The casing 11 is made of resin such as polypropylene, for example, having a certain elasticity and an outstanding strength.

A lowest section of the casing 11 has an air inlet space 12 defined by a dashed line. Air sent from the blower 27a flows into the air-conditioning unit 10 through the space 12. A bottom of the casing 11 located under the space 12 is gradually downward inclined as approaching the blower unit in the vehicle width direction.

Condensation water generated in a discharge side evaporator 27 and a suction side evaporator 28 is stored in a water storage space 11a. The space 11a is located in a bottom section of the air-conditioning unit 10 adjacent to the blower unit. A lowest section of the casing 11 has a drain port 11b protruding from the water storage space 11a, and the condensation water is discharged out of the unit 10 through the port 11b.

The discharge side evaporator 27 and the suction side evaporator 28 of the refrigerating cycle 20 are arranged in this order immediately after the space 12 in air flowing direction. Heat is exchanged between low-pressure refrigerant passing through the evaporator 27, 28 and air sent from the blower 27a. Thus, air to be sent into the passenger compartment is cooled by the evaporator 27, 28.

As shown in FIG. 2, the evaporator unit 30 has an expansion valve 23, a branch part 24, an ejector 25, a discharge side refrigerant pipe 26a, a suction side refrigerant pipe 26b, other than the evaporators 27, 28. The evaporator unit 30 is constructed by integrating the evaporators 27, 28, the expansion valve 23, the branch part 24, the ejector 25, and the pipes 26a, 26b. The ejector type refrigerating cycle 20 and the evaporator unit 30 are to be mentioned later.

As shown in FIG. 1, the evaporator unit 30 is mounted in the air-conditioner, in a state that a front side of heat-exchange core face of the evaporator 27, 28 is upward inclined by 20°, for example, from a horizontal direction.

Air flows upward after passing through the evaporators 27, 28. A heating passage 13 and a bypass passage 14 are defined above the evaporator 28, and air cooled by the evaporators 27, 28 passes through the heating passage 13 or the bypass passage 14. The heating passage 13 is an air passage to introduce air cooled by the evaporator 28 into a heater core 15. The bypass passage 14 is an air passage to bypass the heating passage 13. Air cooled by the evaporator 28 bypasses the heater core 15, when the air flows through the bypass passage 14.

The heater core 15 is a heat exchanger to reheat air cooled by the evaporator 28 using engine-cooling water circulating through a cooling water circuit (not shown) as a heat source. The heater core 15 is upward inclined by 20°, for example, from the horizontal direction, similar to the evaporator 27, 28.

Air passing through the heater core 15 flows into a mixing chamber 16. Air heated by the heater core 15 and air passing through the bypass passage 14 are mixed in the mixing chamber 16. The chamber 16 is located rear of the heater core 15, and is located above the bypass passage 14.

An air mix door 17 is arranged downstream of the evaporator 28 and upstream of the passage 13, 14 in the air flowing direction, and continuously changes a ratio of air to pass through the heating passage 13 to air to pass through the bypass passage 14.

Specifically, the air mix door 17 is made of a slidable film, and continuously changes an inlet area of the heating passage 13 and an inlet area of the bypass passage 14. The air mix door 17 corresponds to a temperature controlling portion to control a temperature of air in the mixing chamber 16 to be sent into the passenger compartment by continuously changing the air ratio.

The air mix door 17 is driven by an actuator (not shown), and the actuator is controlled by a control signal output from the air-conditioning controller. A face opening 18a, a front foot opening 18b, a rear foot opening 18c, and a defroster opening 18d are defined most downstream end of the casing 11 in the air flowing direction. Conditioned-air is sent from the mixing chamber 16 into the passenger compartment through the opening 18a, 18b, 18c, 18d.

The conditioned-air is blown toward an upper body of an occupant of the vehicle through the face opening 18a. The conditioned-air is blown toward a foot of the occupant seated on a front seat of the vehicle through the front foot opening 18b. The conditioned-air is blown toward a foot of the occupant seated on a rear seat of the vehicle through the rear foot opening 18c. The conditioned-air is blown toward an inner face of a front windshield FW of the vehicle through the defroster opening 18d.

A duct is connected to a downstream of the opening 18a, 18b, 18c, 18d, and introduces the conditioned-air. Only a foot duct 181 connected to the rear foot opening 18c is shown in FIG. 1, and the other ducts are omitted in FIG. 1.

A face-defroster door 19a is arranged upstream of the openings 18a, 18d, and simultaneously adjusts open areas of the openings 18a, 18d. The door 19a is made of a rotary door, for example.

A foot door 19b is arranged upstream of the openings 18b, 18c, and simultaneously adjusts open areas of the openings 18b, 18c. The door 19b is made of a rotary door, for example.

The door 19a, 19b corresponds to an air outlet mode switching portion to switch an air outlet mode of the air-conditioner, and is connected to an electric actuator (not shown). The actuator drives the door 19a, 19b to rotate through a link mechanism (not shown), and is controlled by a control signal output from the air-conditioning controller.

The ejector type refrigerating cycle 20 will be described with reference to FIG. 2. Chlorofluorocarbon-base refrigerant is used as refrigerant of the refrigerating cycle 20, and a sub-critical cycle is constructed in which a pressure of high-pressure side refrigerant does not exceed a critical pressure of the refrigerant.

A compressor 21 of the refrigerating cycle 20 draws and compresses refrigerant. The compressor 21 is arranged in the engine compartment, and drive force is transmitted to the compressor 21 from an engine (not shown). The compressor 21 is a variable capacity compressor, so that refrigerant discharge capacity can be controlled by changing a discharge rate. The discharge capacity of the compressor 21 is controlled by a control signal output from the air-conditioning controller.

Alternatively, the compressor 21 may be made of a capacity-fixed compressor. A refrigerant discharge capacity of the capacity-fixed compressor is controlled by changing an operating ratio of electromagnetic clutch. A refrigerant discharge capacity of an electric compressor is controlled by controlling a rotation number of the electric compressor.

A radiator 22 is arranged in the engine compartment, and is connected to a discharge side of the compressor 21. The radiator 22 is a heat exchanger to make high-pressure refrigerant to emit heat by exchanging heat between the high-pressure refrigerant discharged out of the compressor 21 and outside air sent by a cooling fan 22a. A rotation number of the fan 22a is electrically controlled by a control voltage output from the air-conditioning controller. Thus, an amount of the air is controlled.

A receiver 22b is connected to a discharge side of the radiator 22. The receiver 22b is a separator to separate refrigerant flowing out of the radiator 22 into gas and liquid, and stores extra liquid phase refrigerant. The radiator 22 and the receiver 22b are integrated with each other. Alternatively, the radiator 22 and the receiver 22b may be separated from each other.

The radiator 22 may be a sub-cool type condenser including a condensing heat exchanger, a receiver and a supercooling heat exchanger. The condensing heat exchanger condenses refrigerant. The receiver receives refrigerant from the condensing heat exchanger and separates the refrigerant into gas and liquid. The supercooling heat exchanger supercools the saturated liquid phase refrigerant flowing out of the receiver.

The expansion valve 23 may be made of a variable throttle mechanism, and is connected to a liquid refrigerant outlet of the receiver 22b. The expansion valve 23 is a decompressor to decompress high-pressure liquid refrigerant flowing out of the receiver 22b into middle-pressure refrigerant having gas and liquid phases. Further, the expansion valve 23 is a flow amount controlling portion to control an amount of refrigerant flowing out of the valve 23.

The expansion valve 23 operates based on a temperature, for example. Specifically, the expansion valve 23 has a temperature sensor 23a located at a refrigerant outlet of the evaporator 27. A superheat degree of refrigerant flowing out of the evaporator 27 is detected by the sensor 23a based on the temperature and the pressure. An opening degree of the valve 23 is controlled by a mechanical member in a manner that the superheat degree of refrigerant has a predetermined value, so that the refrigerant flow rate can be controlled.

The branch part 24 is connected a discharge side of the expansion valve 23, and a flow of the middle-pressure refrigerant is branched by the branch part 24. The branch part 24 has a three-way joint structure. One opening of the branch part 24 is an inlet of refrigerant, and the other two openings are outlets of refrigerant. The branch part 24 may be produced by forming plural holes in a metal or resin block.

One of the outlets of the branch part 24 is connected to a refrigerant inlet side of a nozzle 25a of the ejector 25, and the other outlet of the branch part 24 is connected to a refrigerant suction port 25b of the ejector 25 through a fixed throttle 29. The ejector 25 corresponds to a refrigerant decompressor to lower a pressure of the middle-pressure refrigerant, and corresponds to a refrigerant circulator to circulate refrigerant using high-speed refrigerant flow injected by the nozzle 25a.

Specifically, the nozzle 25a decompresses the middle-pressure refrigerant in isentropic state by narrowing a passage area of the middle-pressure refrigerant flowing out of the branch part 24. The refrigerant suction port 25b draws refrigerant flowing out of the evaporator 28, and is arranged to communicate with a refrigerant injection port of the nozzle 25a.

The ejector 25 further has a mixer 25c located downstream of the nozzle 25a and the suction port 25b in refrigerant flowing direction. The high-speed refrigerant flowing from the nozzle 25a and the refrigerant drawn from the suction port 25b are mixed in the mixer 25c. As shown in FIGS. 3A and 3B, a refrigerant inlet 27c of the evaporator 27 is connected to a refrigerant outlet 25d of the ejector 25 through the discharge side refrigerant pipe 26a. As shown in FIG. 2, the refrigerant outlet 25d is located downstream of the mixer 25c in the refrigerant flowing direction, and is the most downstream part of the ejector 25.

The refrigerant pipe 26a has a shape in a manner that the passage area of refrigerant is gradually increased in the refrigerant flowing direction. Due to the pipe 26a, refrigerant mixed in the mixer 25c is decelerated, and the pressure of the mixed refrigerant is raised. That is, velocity energy of the mixed refrigerant is converted into pressure energy. The pipe 26a is easily produced by expanding or contracting a usual refrigerant pipe.

Heat is exchanged in the evaporator 27 between low-pressure refrigerant flowing from the ejector 25 through the pipe 26a and air flowing into the casing 11 through the space 12. The low-pressure refrigerant absorbs heat by evaporation. A refrigerant inlet of the compressor 21 is connected to a refrigerant outlet 27d of the evaporator 27 of FIG. 3B.

The suction side evaporator 28 is connected to the refrigerant outlet of the branch part 24 through the throttle 29. The throttle 29 is a suction side decompressor to decompress and expand the middle-pressure refrigerant flowing from the branch part 24. The throttle 29 may be made of a capillary tube or orifice, for example.

Heat is exchanged in the evaporator 28 between low-pressure refrigerant decompressed by the throttle 29 and air passing through the evaporator 27. The low-pressure refrigerant absorbs heat by evaporation. As shown in FIGS. 3A and 3B, the refrigerant suction port 25b of the ejector 25 is connected to a refrigerant outlet 28d of the evaporator 28 through the suction side refrigerant pipe 26b.

The evaporator unit 30 will be described with reference to FIGS. 3A, 3B and 4. The evaporator unit 30 is constructed by integrally assembling the expansion valve 23, the branch part 24, the ejector 25, the refrigerant pipes 26a, 26b and the throttle 29, which are surrounded by a dashed line of FIG. 2.

FIG. 3A is a front view of the evaporator unit 30 seen from the air flowing direction, that is in a direction perpendicular to the heat-exchange face. FIG. 3B is a top view of FIG. 3A. FIG. 4 is a perspective view of the evaporator unit 30.

The evaporators 27, 28 are constructed by dividing a single layered-type heat exchanger into two. That is, the evaporators 27, 28 are integrated with each other. The layered-type heat exchanger is constructed by tubes 31 and fins 32 alternately layered and brazed with each other. Refrigerant flows through the tube 31, and the fin 32 promotes the heat exchange.

The tube 31 is produced by alternately forming projections and depressions on a plate made of metal having high heat conductivity, such as aluminum, and by connecting two of the plates in a manner that the projections oppose to each other. The tube 31 and the fin 32 are partially shown in FIGS. 3A and 4.

The tube 31 of the discharge side evaporator 27 and the tube 31 of the suction side evaporator 28 do not communicate with each other, because the single layered-type heat exchanger is divided into the evaporators 27, 28.

The evaporator 27, 28 has tanks 27b, 28b on both ends of the tubes 31. Refrigerant gathers into the tank 27b, 28b from the tubes 31, or is distributed into the tubes 31 from the tank 27b, 28b. The tank 27b, 28b has a through hole passing through the tube 31.

The tank 27b, 28b is defined by layering the tubes 31 in a layering direction, and communicates with the tubes 31 of the evaporator 27, 28. The through hole passing through the tube 31 located most periphery side in the layering direction is sealed, and the through hole passing through the tube 31 located approximately center in the layering direction is sealed. Therefore, an inner space of the tank 27b, 28b is divided into two spaces in the layering direction, so that a flowing direction of refrigerant is changed between the tubes 31.

A block 33 has a refrigerant inlet 33a and a refrigerant outlet 33b of the evaporator unit 30. The expansion valve 23, the branch part 24, the ejector 25 and the block 33 are integrally connected with each other by a fastening portion such as a bolt. Refrigerant ports of the valve 23, the branch part 24, the ejector 25 and the block 33 directly communicate with each other.

Specifically, the block 33, the expansion valve 23, the branch part 24, and the ejector 25 are arranged in this order in the layering direction of the tubes 31. The ejector 25 has a longitudinal direction corresponding to the layering direction. A seal member such as an O-ring is arranged at connections of the refrigerant ports so as to prevent a leakage from the connections.

When the evaporator unit 30 is mounted in the air-conditioner, the refrigerant outlet 28d of the suction side evaporator 28 is located upper than the suction port 25b of the ejector 25 in a circumference direction of the refrigerant pipe 26b, and the outlet 28d is made of opening that opens upward compared with the horizontal direction.

As shown in FIG. 3A, the suction side refrigerant pipe 26b has a communication pipe 261 and a connection pipe 262. The communication pipe 261 communicates with the refrigerant outlet 28d of the tank 28b of the suction side evaporator 28. The connection pipe 262 connects the communication pipe 261 to the suction port 25b of the ejector 25.

The communication pipe 261 extends in the layering direction of the tubes 31, and has a curve shape to approach the refrigerant suction port 25b of the ejector 25. When the tubes 31 and the fins 32 are brazed with each other, the tank 28b and the communication pipe 261 are brazed with each other, at the same time.

An end of the connection pipe 262 is fixed to the suction port 25b, and has a curve shape extending from the suction port 25b toward the communication pipe 261. An end of the pipe 261, 262 has a flange, and the flange of the pipe 261 is connected to the flange of the pipe 262 using a bolt, for example.

The pipe 26b extends only in the horizontal direction or extends downward from the outlet 28d in a state that the evaporator unit 30 is mounted in the air-conditioner. That is, the pipe 26b has a shape in a manner that refrigerant flows downward from the outlet 28d of the evaporator 28 to the suction port 25b of the ejector 25.

In contrast, the discharge side refrigerant pipe 26a has a distribution pipe 263 and a connection pipe 264. The distribution pipe 263 communicates with the refrigerant inlet 27c of the tank 27b of the discharge side evaporator 27. The connection pipe 264 connects the distribution pipe 263 to the refrigerant outlet 25d of the ejector 25.

The distribution pipe 263 extends in the layering direction of the tubes 31. Due to the pipe 263, refrigerant flowing out of the outlet 25d of the ejector 25 is equally distributed into the tubes 31. When the tubes 31 and the fins 32 are brazed with each other, the tank 27b and the distribution pipe 263 are brazed with each other, at the same time.

An end of the connection pipe 264 is fixed to the distribution pipe 263, and has a curve shape extending from the distribution pipe 263 to the refrigerant outlet 25d of the ejector 25. An end of the pipe 264 has a flange, and the refrigerant outlet 25d of the ejector 25 has a flange. The flanges are connected with each other using a bolt, for example.

As shown in FIG. 3B, the refrigerant outlet 27d of the discharge side evaporator 27 is connected to the block 33 through a refrigerant pipe. The refrigerant inlet 28c of the suction side evaporator 28 is connected to the branch part 24 through a capillary tube corresponding to the throttle 29. Thus, refrigerant flows inside of the evaporator unit 30 in a chain line arrow direction of FIG. 4.

The evaporator unit 30 is constructed by using the pipes 26a, 26b. Therefore, the evaporators 27, 28 integrated with each other are distanced from the block 33, the expansion valve 23, the branch part 24 and the ejector 25 integrated with each other, without contacting.

As shown in FIG. 1, the evaporators 27, 28 are arranged inside of the casing 11 of the air-conditioning unit 10. The block 33, the expansion valve 23, the branch part 24, and the ejector 25 are arranged under the casing 11 of the air-conditioning unit 10 in the passenger compartment located on the inner side of the floor panel FP.

The longitudinal direction of the ejector 25 is approximately parallel with the vehicle width direction. The block 33, the expansion valve 23, and the branch part 24 are omitted in FIG. 1.

Electric controlling parts of the air-conditioner will be described below. The air-conditioning controller includes a microcomputer and a periphery circuit. The microcomputer has CPU, ROM, RAM, etc. Calculation and processing are performed based on air-conditioning control program memorized in the ROM. The controller controls the compressor 21, the fan 22a, the blower 27a connected to an output side of the controller.

Sensors (not shown) used for controlling air-conditioning are connected to an input side of the air-conditioning controller. An inside air sensor detects a temperature of air in the passenger compartment. An outside air sensor detects an outside air temperature. A solar sensor detects a solar radiation amount in the passenger compartment. An evaporator temperature sensor detects an evaporator temperature of air blown out of the discharge side evaporator 27.

A console panel (not shown) is arranged near an instrument board located at a front part of the passenger compartment, and is connected to the input side of the air-conditioning controller. Operation signals input into switches of the console panel are output into the air-conditioning controller. The switches may include an activation switch of air-conditioning, or a temperature setting switch used for setting a target temperature of the passenger compartment.

Operation of the air-conditioner will be described below. When the air-conditioner is turned on, signals output from the sensors and the console panel are read by the controller. A target temperature TAO of air blown into the passenger compartment is set based on the signals.

Operation status of components connected to the output side of the controller are set based on the calculated target temperature TAO and the signals output from the sensors. For example, a target air amount sent from the blower 27a, that is, a control voltage input into the motor of the blower 27a is determined based on the target temperature TAO by referring to a control map memorized in the controller. The target air amount is set larger when the target temperature TAO is high or low, compared with a case where the target temperature TAO is middle.

A refrigerant discharge capacity of the compressor 21, that is, a control signal to be input into the compressor 21 defines a target evaporator blow-off temperature TEO of the evaporator 27 based on the target temperature TAO by referring to a control map memorized in the controller. A blow-off air temperature Te is determined based on a deviation between the value of TEO and the value of Te, in a manner that the value of Te approaches the value of TEO using feedback control.

A control signal input into the actuator of the air mix door 17 is determined using the target temperature TAO, the blow-off air temperature Te and an engine cooling-water temperature Tw in a manner that air to be sent into the passenger compartment has a predetermined temperature.

The control voltage and the control signal are output into the compressor 21, the fan 22a and the blower 27a. A routine of reading the signals, calculating the target temperature TAO, determining the operation status of the components, and outputting the control voltage and the control signal is repeated in this order with a predetermined period until the air-conditioner is turned off.

High-temperature high-pressure refrigerant discharged out of the compressor 21 flows into the radiator 22. The high-temperature refrigerant is cooled by outside air, and is condensed by the radiator 22. The high-pressure refrigerant flowing out of the radiator 22 is separated into gas and liquid in the receiver 22b. The liquid phase refrigerant separated by the receiver 22b flows into the evaporator unit 30 through the inlet 33a.

Refrigerant flowing into the inlet 33a is decompressed and expanded by the expansion valve 23 in isenthalpic state so as to have middle-pressure. At this time, the valve opening of the expansion valve 23 is controlled in a manner that the superheat degree of refrigerant flowing out of the evaporator 27 has a predetermined value. The expanded refrigerant is branched by the branch part 24 into the nozzle 25a of the ejector 25 and the throttle 29.

A ratio of refrigerant flowing into the nozzle 25a to refrigerant flowing into the throttle 29 is determined by characteristics of the nozzle 25a and the throttle 29. Further, the ratio is determined in a manner that the evaporators 27, 28 have suitable refrigerating capacities, so that a cycle efficiency (COP) can be made higher as a whole cycle.

The middle-pressure refrigerant flowing into the ejector 25 from the branch part 24 is further decompressed by the nozzle 25a in an isentropic state. At this time, pressure energy of refrigerant is converted into velocity energy by the nozzle 25a. Liquid phase refrigerant and gas phase refrigerant are injected with high-speed from the injection port of the nozzle 25a. At this time, refrigerant flowing out of the suction side evaporator 28 is drawn into the refrigerant suction port 25b due to the suction action of the injected refrigerant.

The refrigerant injected from the nozzle 25a and the refrigerant drawn through the suction port 25b are mixed in the mixer 25c. The mixed refrigerant flows out of the ejector 25 through the outlet 25d, and flows into the pipe 26a. Velocity energy of refrigerant is changed into pressure energy in the pipe 26a, because the refrigerant passage area is increased in the refrigerant pipe 26a. Thus, the pressure of refrigerant is raised.

Refrigerant flowing out of the pipe 26a flows into the discharge side evaporator 27. The low-pressure refrigerant flowing into the evaporator 27 absorbs heat from air flowing in the casing 11 by evaporation. Therefore, the air is cooled, and the cooled air is sent into the passenger compartment as conditioned-air. Gas phase refrigerant flowing out of the evaporator 27 flows through the outlet 33b, and is drawn and compressed by the compressor 21 again.

In contrast, the middle-pressure refrigerant flowing into the throttle 29 from the branch part 24 is decompressed and expanded by the throttle 29 into low-pressure refrigerant in isenthalpy state, and flows into the suction side evaporator 28. The low-pressure refrigerant absorbs heat from air passing through the evaporator 27 by evaporation in the suction side evaporator 28. Thereby, the air to be sent into the passenger compartment is further cooled. Refrigerant flowing out of the evaporator 28 is drawn into the suction port 25b of the ejector 25 through the pipe 26b.

According to the first embodiment, air sent by the fan 27a is efficiently cooled by the evaporator unit 30.

Because the pipe 26b raises the pressure of refrigerant, a refrigerant evaporation temperature of the evaporator 27 can be raised than that of the evaporator 28. Therefore, a temperature difference can be secured between the refrigerant evaporation temperature of the evaporator 27, 28 and the temperature of air to be sent into the passenger compartment, so that the air can be efficiently cooled.

Further, as shown in FIG. 1, air cooled by the evaporator unit 30 flows into the heating passage 13 or the bypass passage 14 based on the opening degree of the air mix door 17. Air flowing into the heating passage 13 is heated by the heater core 15, and the heated air is mixed with air passing through the bypass passage 14 in the mixing chamber 16. A temperature of the air is controlled in the mixing chamber 16, and the conditioned-air is blown into the passenger compartment through the opening 18a, 18b, 18c, 18d.

The air-conditioner performs a cooling operation by cooling the passenger compartment using the conditioned-air. The air-conditioner performs a heating operation by heating the passenger compartment using the conditioned-air.

Further, the ejector 25 and the evaporators 27, 28 are integrated into the evaporator unit 30, due to the refrigerant pipes 26a, 26b. Thereby, a relative position between the ejector 25 and the evaporators 27, 28 can be flexibly controlled by changing length of the refrigerant pipe 26a, 26b.

That is, the outer shape of the evaporator unit 30 can be easily made suitable for the air-conditioner having various sizes and shapes. Furthermore, the block 33, the expansion valve 23, the branch part 24, and the ejector 25 can be arranged in a space defined between the floor panel FP and the casing 11.

The space defined between the floor panel FP and the casing 11 can be used effectively. Ventilation resistance of the air passage in the casing 11 can be prevented from being increased by the block 33, the expansion valve 23, the branch part 24, and the ejector 25.

The suction side refrigerant pipe 26b has a shape in a manner that refrigerant flows downward from the refrigerant outlet 28d of the evaporator 28 into the refrigerant suction port 25b of the ejector 25. Therefore, liquid phase refrigerant having density higher than that of gas phase refrigerant can be introduced into the suction port 25b due to gravity if refrigerant having two-phase, that is liquid and gas, flows out of the outlet 28d of the evaporator 28.

If the length of the pipe 26b cannot be made shorter by conditions of the air-conditioner, pressure loss of refrigerant is increased in the pipe 26b. Even in this case, according to the first embodiment, the ejector 25 can draw refrigerant from the suction port 25b, and the evaporator 28 of the refrigerating cycle 20 can achieve sufficient refrigerating performance.

The ejector 25 may be located in an area X of FIG. 1, other than the present position. If the suction port 25b of the ejector 25 is located lower than the refrigerant outlet 28d of the evaporator 28 in a state that the evaporator unit 30 is mounted in the air-conditioner, the same effect can be obtained.

The suction port 25b of the ejector 25 is open upward than the horizontal direction. Therefore, refrigerant flowing downward in the pipe 26b efficiently flows into the suction port 25b, due to the gravity force.

The refrigerant passage area of the pipe 26a is gradually made larger in the refrigerant flowing direction. Therefore, the pipe 26a may correspond to a diffuser of a usual ejector. Therefore, a diffuser can be eliminated in the ejector 25, so that axial length of the ejector 25 can be made shorter. Thus, the size of the evaporator unit 30 can be made smaller.

As shown in FIG. 4, the expansion valve 23, the branch part 24, the ejector 25, the refrigerant pipes 26a, 26b, the evaporators 27, 28, and the block 33 are integrated into the evaporator unit 30, and the evaporator unit 30 is mounted in the air-conditioner. Therefore, the components of the refrigerating cycle 20 can be easily and flexibly mounted in the air-conditioner.

In contrast, there may be a case where the evaporator unit 30 is unable to be mounted in the air-conditioner. In this case, the ejector 25 may be connected to the evaporators 27, 28 using the pipes 26a, 26b, after the evaporators 27, 28 are mounted in the air-conditioning unit 10.

A connection structure to connect the suction port 25b of the ejector 25 and the refrigerant outlet 28d of the evaporator 28 may be achieved by the suction side refrigerant pipe 26b having a shape in a manner that refrigerant flows downward from the refrigerant outlet 28d of the evaporator 28 into the suction port 25b of the ejector 25.

Even in this case, the ejector 25 can draw refrigerant from the suction port 25b, and the evaporator 28 can achieve sufficient refrigerating performance, similar to the above case, even if the length of the pipe 26b cannot be made shorter by the conditions of the air-conditioner.

Second Embodiment

In a second embodiment, as shown in FIG. 5, a discharge side refrigerant pipe 26a is connected to a rear tank 27b located rear side of a discharge side evaporator 27, while the refrigerant pipe 26a of the first embodiment is connected to a front tank located front side of the evaporator 27.

FIG. 5 is a cross-sectional view illustrating the evaporator unit 30 mounted in the air-conditioning unit 10. It should be understood that throughout FIGS. 5-11, corresponding reference numerals indicate like or corresponding parts and features.

According to the second embodiment, the refrigerant pipe 26b has a shape in a manner that refrigerant flows downward from the refrigerant outlet 28d of the evaporator 28 into the refrigerant suction port 25b of the ejector 25. The same effect can be obtained in the second embodiment as the first embodiment. The ejector 25 may be located in the area X of FIG. 1, similar to the first embodiment.

Third Embodiment

The ejector 25 is located under the casing 11 of the air-conditioning unit 10 in the above embodiments. In a third embodiment, as shown in FIG. 6, the ejector 25 is located rear of the casing 11 and under the rear foot duct 181.

According to the third embodiment, a space defined between the casing 11 and the duct 181 can be effectively used. Further, the same effect can be obtained in the third embodiment as the first embodiment. The ejector 25 may be located in an area Y of FIG. 6, other than the present position, when the evaporator unit 30 is mounted in the air-conditioner.

Fourth Embodiment

In a fourth embodiment, as shown in FIG. 7, a discharge side refrigerant pipe 26a is connected to a rear tank 27b located rear side of a discharge side evaporator 27, while the refrigerant, pipe 26a of the third embodiment is connected to a front tank located front side of the evaporator 27.

The same effect can be obtained in the fourth embodiment as the third embodiment. The ejector 25 may be located in the area Y of FIG. 6, similar to the third embodiment.

Fifth Embodiment

As shown in FIG. 8, the air-conditioning unit 10 and the evaporator unit 30 are modified in a fifth embodiment, compared with the first embodiment. FIG. 8 is a cross-sectional view illustrating the air-conditioning unit 10 having the evaporator unit 30.

Specifically, the air inlet space 12 shown in a dashed line of FIG. 8 is located in a most front section of the casing 11 of the air-conditioning unit 10. The discharge side evaporator 27 and the suction side evaporator 28 are arranged in this order in the air flowing direction, and are located immediately downstream of the space 12 in the air flowing direction.

The heat-exchange face of the evaporator 27, 28 is set approximately parallel to a vertical direction. The casing 11 has a water storage space 11a located under the evaporators 27, 28, and condensation water generated in the evaporators 27, 28 is stored in the space 11a. The space 11a extends in the vehicle width direction.

The heating passage 13 and the bypass passage 14 are defined downstream of the evaporators 27, 28 in the air flowing direction, and air passes through the passage 13, 14 after passing through the evaporators 27, 28. The bypass passage 14 is located above the heating passage 13. Further, an auxiliary bypass passage 14a and an auxiliary bypass door 14b to open/close the passage 14a are defined above the bypass passage 14. When the maximum cooling operation is required for the air-conditioner, an amount of cool air is increased, due to the passage 14a.

The door 14b is connected to the actuator for the air mix door 17 through a link mechanism (not shown), and is driven by the actuator. Specifically, when the maximum cooling operation is required, the air mix door 17 totally opens the bypass passage 14 and totally closes the heating passage 13, and the auxiliary door 14b opens the auxiliary bypass passage 14a.

Another bypass passage 14c is defined under the heating passage 13 and the heater core 15. Air cooled by the evaporator 28 is introduced into the rear foot opening 18c by the passage 14c bypassing the heater core 15.

Another air mix door 17a is arranged at most downstream of the passage 14c in the air flowing direction. The door 17a continuously changes a ratio of air heated by the heater core 15 to air passing through the passage 14c.

Similar to the air mix door 17, the door 17a corresponds to a temperature controlling portion to control a temperature of air blown toward the rear seat. The door 17a is driven by an original electric actuator (not shown), and the actuator is controlled by a control signal output from the air-conditioning controller.

A rear face opening 18e is defined at the most downstream of the casing 11 in the air flowing direction other than the openings 18a, 18b, 18c, 18d. Conditioned-air is blown toward an upper body of an occupant seated on the rear seat through the opening 18e.

A face door 19c is arranged upstream of the opening 18a in the air flowing direction, and is made of cantilever board door to control an opening area of the opening 18a. A defroster door 19d is arranged upstream of the opening 18d in the air flowing direction, and is made of cantilever board door to control an opening area of the opening 18d.

A rear face-foot door 19e is arranged upstream of the openings 18c, 18e in the air flowing direction, and is made of butterfly door to simultaneously control opening areas of the openings 18c, 18e.

As shown in FIG. 8, the ejector 25 is located downstream of the evaporator 27 in the air flowing direction. Specifically, the ejector 25 is located in the space 11a defined rear and lower side of the evaporator 27, and extends in the vehicle width direction.

That is, the ejector 25 is located inside of the casing 11. Specifically, the evaporator unit 30 constructed by integrating the branch part 24, the ejector 25, the pipes 26a, 26b, the evaporators 27, 28 and the throttle 29 is arranged inside of the casing 11. The branch part 24 is omitted in FIG. 8.

The expansion valve 23 and the block 33 are located outside of the casing 11, and are connected to the evaporator unit 30 through a connecting member passing through a through hole of the casing 11. The construction of the refrigerating cycle 20 of the present embodiment is similar to that of the first embodiment.

Operations of the air-conditioner of the present embodiment will be described below. A target blow-off temperature TAOre is calculated other than the target blow-off temperature TAO, and corresponds to a target temperature of air to be blown toward the rear seat of the passenger compartment.

Further, a control signal input into the actuator of the air mix door 17a is determined based on the temperature TAOre, Te and the engine cooling-water temperature Tw in a manner that the temperature of air blown toward the rear seat has a predetermined temperature.

Other operations are similar to the first embodiment, so that the air-conditioner can perform suitable cooling or heating operation, and that the outer shape of the evaporator unit 30 can be easily made suitable for conditions of a device to which the evaporator unit 30 is mounted.

The suction side refrigerant pipe 26b has a shape in a manner that refrigerant flows downward from the outlet 28d of the evaporator 28 into the refrigerant suction port 25b of the ejector 25. Therefore, liquid phase refrigerant flowing out of the outlet 28d of the evaporator 28 can be introduced into the suction port 25b due to gravity, so that the evaporator 28 of the refrigerating cycle 20 can have sufficient refrigerating performance.

Further, the ejector 25 is arranged inside of the space 11a not constructing the air passage. Therefore, ventilation resistance of the casing 11 can be restricted from being increased by the ejector 25.

Sixth Embodiment

In a sixth embodiment, as shown in FIG. 9, a discharge side refrigerant pipe 26a is connected to a lower tank 27b located lower side of a discharge side evaporator 27, while the refrigerant pipe 26a of the fifth embodiment is connected to an upper tank located upper side of the evaporator 27.

According to the sixth embodiment, the water storage space 11a of the casing 11 can be effectively used, and the suction side refrigerator 28 can achieve sufficient refrigerating performance, similar to the fifth embodiment.

Seventh Embodiment

The ejector 25 is arranged in the ward storage space 11a downstream of the evaporator 27 in the air flowing direction in the fifth and sixth embodiments. In a seventh embodiment, as shown in FIG. 10, the ejector 25 is arranged upstream of the evaporator 28 in the air flowing direction.

Specifically, the ejector 25 is located on the front and lower side of the evaporator 28, so that the ejector 25 is not overlap with the heat-exchange face of the evaporator 28 in the air flowing direction. That is, the ejector 25 is located in a space defined among the most front face of the casing 11, the bottom face of the casing 11 and a member to support the evaporator unit 30, and the space is located lower than the lower end of the heat-exchange face of the evaporator 28.

According to the seventh embodiment, the ejector 25 does not increase the ventilation resistance of air passing by the heat-exchange face of the evaporator 28. Therefore, the suction side refrigerator 28 can achieve sufficient refrigerating performance, similar to the fifth embodiment.

Eighth Embodiment

In an eighth embodiment, as shown in FIG. 10, a discharge side refrigerant pipe 26a is connected to a lower tank 27b located lower side of a discharge side evaporator 27, while the refrigerant pipe 26a of the seventh embodiment is connected to an upper tank located upper side of the evaporator 27.

According to the eighth embodiment, approximately the same effect can be obtained as the seventh embodiment.

Other Embodiment

The present invention is not limited within the above embodiments. Changes and modifications are to be understood as being within the scope of the present invention.

The longitudinal direction of the ejector 25 is not limited to correspond to the vehicle width direction. For example, the ejector 25 may be arranged in the area X of FIG. 1 or the area Y of FIG. 6 in inclined state in a manner that the refrigerant outlet 25d of the ejector 25 is located upper than an inlet of the nozzle 25a of the ejector 25.

The refrigerant outlet 25d of the ejector 25 may be located upper than the refrigerant inlet 27c of the evaporator 27, because refrigerant flowing through the pipe 26a from the outlet 25d can flow into the evaporator 27 without using gravity force, due to the high-speed refrigerant flow injected from the nozzle 25a.

The branch part 24 may be eliminated from the evaporator unit 30.

For example, the receiver 22b and the branch part 24 may be eliminated from the refrigerating cycle 20 of FIG. 2. In this case, a low-pressure side gas-liquid separator is arranged downstream of the evaporator 27 as an accumulator, and liquid refrigerant separated by the accumulator flows into the evaporator 28. Further, the evaporator 27 may be eliminated from the cycle 20 in this case.

For example, the evaporator 27 may be eliminated from the refrigerating cycle 20 of FIG. 2, and an inner heat exchanger is arranged in the cycle 20. The inner heat exchanger exchanges heat between low-pressure refrigerant flowing out of the pipe 26a and middle-pressure refrigerant flowing from the branch part 24 toward the throttle 29. In this case, enthalpy of refrigerant flowing into the evaporator 28 can be lowered, so that the refrigerating performance of the evaporator 28 can be increased.

For example, the branch part 24 may be arranged on the outlet side of the ejector 25 in the refrigerating cycle 20 of FIG. 2. In this case, when refrigerant is branched into two flows, one of the flows is supplied to discharge side the evaporator 27, and the other flow is supplied to the suction side evaporator 28.

The pressure of the mixed refrigerant is raised by the discharge side refrigerant pipe 26a in the above embodiments. Alternatively, a diffuser may be arranged downstream of the mixer 25c of the ejector 25, and refrigerant passage area is gradually increased by the diffuser, so as to raise the pressure of refrigerant. Further, the mixer 25c may be smoothly connected to the diffuser. In this case, the mixer 25c and the diffuser are integrated with each other as a pressure-raising portion.

The refrigerant of the refrigerating cycle 20 is not limited to the chlorofluorocarbons. Alternatively, hydrocarbons or carbon dioxide may be used as the refrigerant. Further, the evaporator unit 30 may be applied to a supercritical refrigerating cycle in which a pressure of high-pressure side refrigerant exceeds the critical pressure of the refrigerant.

The evaporator unit 30 is not limited to be applied to the refrigerating cycle 20 of the air-conditioner mounted in the vehicle. The evaporator unit 30 may be applied to a commercial-use refrigerator device, a cooling device for a vending machine, or a showcase with cold storage function.

The evaporator unit 30 is not limited to be constructed by integrating the expansion valve 23, the branch part 24, the ejector 25, the pipes 26a, 26b, the evaporators 27, 28 and the throttle 29.

The evaporator unit 30 may be constructed by integrating at least the ejector 25, the suction side refrigerant pipe 26b and the suction side evaporator 28. Therefore, the ejector 25 can draw refrigerant from the suction port 25b, and the evaporator 28 can achieve sufficient refrigerating performance. That is, the evaporator unit 30 may not include the discharge side evaporator 27.

The evaporators 27, 28 are not limited to be constructed by dividing the single layered-type heat exchanger into two.

For example, fins of the evaporator 27 and fins of the evaporator 28 are made common in other tank-and-tube type heat exchanger, similar to the above embodiment. In this case, each of the evaporators 27, 28 is defined by tubes contacting the common fins.

For example, the evaporators 27, 28 are produced separatedly in advance, and the separated evaporators 27, 28 are integrated with each other through brazing, for example. Alternatively, the evaporators 27, 28 may be integrated with each other with a predetermined interval equal to or smaller than 10 mm through a mechanical connector such as bolt.

The evaporators 27, 28 are not limited to be located indoor of the vehicle, and the radiator 22 is not limited to be located outdoor of the vehicle. Alternatively, the evaporators 27, 28 may be outdoor heat exchangers to absorb heat from a heat source such as air, and the radiator 22 may be an indoor heat exchanger to heat refrigerant such as air or water.

The refrigerant pipe 26b is not limited to have a shape in a manner that refrigerant flows downward from the refrigerant outlet 28d of the evaporator 28 to the suction port 25b of the ejector 25 in the state that the evaporator unit 30 is mounted in the air-conditioner of the vehicle.

The refrigerant outlet 28d is located upper than the suction port 25b at least in the state that the evaporator unit 30 is mounted in the air-conditioner of the vehicle. Therefore, the refrigerating performance of the evaporator 28 can be improved, and the evaporator unit 30 is easily made suitable for the conditions of the air-conditioner.

If the refrigerant outlet 28d is located upper than the suction port 25b, refrigerant flowing upward in the vertical direction is smaller than refrigerant flowing downward in the vertical direction, as a whole of the refrigerant pipe 26b. Therefore, if two-phase, i.e., gas and liquid, refrigerant flows out of the outlet 28d of the evaporator 28, the liquid refrigerant having density higher than that of the gas refrigerant is easily introduced into the suction port 25b using the gravity force.

Even if the pipe 26b slightly has a section in which refrigerant flows upward in the vertical direction, the evaporator unit 30 can be easily fitted to the conditions of the air-conditioner. Further, the liquid refrigerant having density higher than that of the gas refrigerant is easily introduced into the suction port 25b using the gravity force, similarly to the above embodiments. Thus, the refrigerating performance of the evaporator 28 can be improved.

Refrigerant of the pipe 26b is not limited to flow downward just in the vertical direction. The pipe 26b may have a section inclined relative to the vertical direction. Further, the pipe 26b may have a horizontal section extending in the horizontal direction. That is, refrigerant may flow in the horizontal direction in the horizontal section of the pipe 26b.

Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.

EVAPORATOR UNIT

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CPC

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