Air conditioner for vehicle

Abstract

In a vehicle air conditioner, a heating heat exchanger is disposed in an air passage of a casing to heat air to be blown toward a vehicle compartment by performing heat exchange between air and a heating fluid, a heat radiation portion is disposed to radiate heat to the heating fluid before being heat-exchanged in the heating heat exchanger, a heat absorption portion is disposed to absorb heat from the heating fluid after being heat-exchanged in the heating heat exchanger, and a Peltier element is disposed between the heat radiation portion and the heat absorption portion to pump heat from the heat absorption portion to the heat radiation portion. Furthermore, the heat radiation portion is disposed in the air passage of the casing, in which the heating heat exchanger is disposed. Thus, heat discharged from the Peltier element can be effectively used.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2010-246948 filed on Nov. 3, 2010, the contents of which are incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to an air conditioner for a vehicle.

BACKGROUND

Conventionally, a vehicle air conditioner is provided with a heating heat exchanger that heats air to be blown into a vehicle compartment by using engine coolant as a heat source, and an auxiliary heater for performing supplementary heating operation, for example, in Patent Document 1 (JP 2007-278624A corresponding to U.S. 2008/0041071A1) or Patent Document 2 (JP 2008-126820A).

However, in a case where the engine coolant is simply heated by the auxiliary heater, the heat quantity without being heat-exchanged with air in the heating heat exchanger may be radiated from the surface of an engine coolant system, and the heated quantity may be uselessly consumed.

This problem is also caused when a fluid other than the engine coolant is used as the heat source.

SUMMARY

The present invention is made in view of the above matters, and it is an object of the present invention to provide an air conditioner for a vehicle, in which a heat amount discharged from a Peltier element can be effectively used.

It is another object of the present invention to provide an air conditioner for a vehicle, in which a heat amount discharged from a Peltier element can be effectively used while mounting performance of the Peltier element to the vehicle can be improved.

According to an aspect of the present invention, an air conditioner for a vehicle includes a casing defining an air passage through which air flows into a vehicle compartment, a heating heat exchanger disposed in the air passage of the casing to heat air to be blown toward the vehicle compartment by performing heat exchange between air and a heating fluid, a heat radiation portion disposed to radiate heat to the heating fluid before being heat-exchanged in the heating heat exchanger, a heat absorption portion disposed to absorb heat from the heating fluid after being heat-exchanged in the heating heat exchanger, and a Peltier element disposed between the heat radiation portion and the heat absorption portion to pump heat from the heat absorption portion to the heat radiation portion. In the vehicle air conditioner, because the heat radiation portion is disposed in the air passage of the casing, in which the heating heat exchanger is disposed, heat discharged from the Peltier element can be effectively used for heating air to be blown into the vehicle compartment.

Furthermore, by mounting the casing to the vehicle, it is possible for the heat radiation portion, heat absorption portion and the Peltier element to be mounted to the vehicle, thereby improving the mounting performance in the vehicle. For example, the heat radiation portion, the Peltier element and the heat absorption portion may be formed integrally with the heating heat exchanger.

The heating heat exchanger may include a passage forming member defining a heating fluid passage in which the heating fluid flows. In this case, the heat radiation portion may be configured by a heating-fluid inlet side portion of the passage forming member, the heat absorption portion may be configured by a heating-fluid outlet side portion of the passage forming member, and the Peltier element may be arranged between the heating-fluid inlet side portion and the heating-fluid outlet side portion of the passage forming member. Furthermore, the heat radiation portion configured by the heating-fluid inlet side portion of the passage forming member may be a part of a heat-exchanging portion in which the heating fluid is heat-exchanged with air.

The heating heat exchanger may include a first heating heat exchanger, and a second heating heat exchanger disposed to heat air after passing through the first heating heat exchanger. In this case, the heat radiation portion, the Peltier element and the heat absorption portion may be provided at least at the second heating heat exchanger, in the first and second heating heat exchangers. Furthermore, the heat radiation portion and the heat absorption portion may be configured such that the heating fluid flowing out of the first heating heat exchanger is joined to the heating fluid flowing in the heat absorption portion or the heating fluid before flowing into the heat absorption portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:

FIG. 1 is a schematic diagram showing an air conditioner for a vehicle according to a first embodiment of the present invention;

FIG. 2 is a perspective view showing a first heater core and a second heater core in the air conditioner shown in FIG. 1;

FIG. 3 is a schematic diagram showing a configuration of the second heater core according to the first embodiment;

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3;

FIG. 5 is a block diagram showing an air conditioning controller in the air conditioner, according to the first embodiment;

FIG. 6 is a flowchart showing a control process performed by the air conditioning controller shown in FIG. 5;

FIG. 7 is a flow diagram showing a detail control at step S4 of FIG. 6;

FIG. 8 is a graph showing the relationship between a passage height of a tube in the second heater core and a heat transmission efficiency, according to the first embodiment;

FIG. 9 is a schematic diagram showing a configuration of a second heater core according to a second embodiment of the present invention;

FIG. 10 is a schematic diagram showing a configuration of a second heater core according to a third embodiment of the present invention;

FIG. 11 is a schematic diagram showing a configuration of a second heater core according to a fourth embodiment of the present invention;

FIG. 12 is a schematic diagram showing a configuration of a second heater core according to a fifth embodiment of the present invention;

FIG. 13 is a perspective view showing a first heater core and a second heater core according to a sixth embodiment of the present invention;

FIG. 14 is a perspective view showing a first heater core and a second heater core according to a seventh embodiment of the present invention;

FIG. 15 is a schematic perspective view showing a first heater core and a second heater core according to an eighth embodiment of the present invention;

FIG. 16 is a schematic diagram showing an air conditioner for a vehicle according to a ninth embodiment of the present invention;

FIG. 17 is a schematic diagram showing an air conditioner for a vehicle according to a tenth embodiment of the present invention;

FIG. 18 is a schematic diagram showing an air conditioner for a vehicle according to an eleventh embodiment of the present invention;

FIG. 19 is a schematic diagram showing an air conditioner for a vehicle according to a twelfth embodiment of the present invention; and

FIG. 20 is a schematic diagram showing an air conditioner for a vehicle, in a comparison example of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.

First Embodiment

A first embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG. 1 is a schematic diagram showing an air conditioner 1 for a vehicle according to the first embodiment of the present invention. For example, the air conditioner of the first embodiment is mounted to a hybrid car which obtains driving force from an engine (combustion engine) EG and an electric motor. Thus, the engine EG is an example of a driving device for obtaining a driving force for a vehicle running in the invention.

In the hybrid vehicle of the embodiment, the engine EG is operated or stopped in accordance with a traveling load of the vehicle. Thus, the hybrid vehicle can be switched to a traveling state in which the vehicle is traveled by using driving force from both of the engine EG and the electrical motor for traveling, or switched to a traveling state (i.e., EV traveling state) in which the vehicle is traveled only by using the electrical motor for traveling while the engine is stopped. Fuel consumption can be reduced compared with a usual car that obtains driving force from only engine EG.

The vehicle air conditioner 1 is provided with an interior air conditioning unit 10 shown in FIG. 1, and an air conditioning controller 60 (NC ECU) shown in FIG. 5.

The interior air conditioning unit 10 is located inside of an instrument panel (i.e., dash panel) positioned at the frontmost portion in the vehicle compartment. The interior air conditioning unit 10 includes an air conditioning casing 11 forming an outer shell and defining the air passage. In the air conditioning casing 11, a blower 12, an evaporator 13, a first heater core 14, a second heater core 15 and the like are disposed.

The casing 11 defines the air passage through which air flows into the vehicle compartment. The casing 11 is made of a resin (e.g., polypropylene) having a suitable elasticity and being superior in the strength. An inside/outside air switching box 20 is located at the most upstream side to selectively introduce inside air or/and outside air into the casing 11. Here, inside air is air inside the vehicle compartment, outside air is air outside the vehicle compartment.

More specifically, the inside/outside air switching box 20 is provided with an inside air introduction port 21 for introducing inside air into the casing 11, and an outside air introduction port 22 for introducing outside air into the casing 11. An inside/outside air switching door 23 is disposed in the inside/outside air switching box 20 to continuously adjust open areas of the inside air introduction port 21 and the outside air introduction port 22. Therefore, the inside/outside air switching door 23 can adjust a ratio between a flow amount of inside air (i.e., air inside the vehicle compartment) introduced from the inside air introduction port 21 and a flow amount of outside air (i.e., air outside the vehicle compartment). The inside/outside air switching door 23 is driven by an electrical actuator 71, and operation of the electrical actuator 71 is controlled by a control signal output from the air conditioning controller 60.

The blower 12 is disposed in the casing 11 at a downstream air side of the inside/outside air switching box 20, to blow air drawn via the inside/outside air switching box 20 toward the interior of the vehicle compartment. The blower 12 is an electrical blower having a centrifugal multi-blade fan (e.g., sirocco fan) 12a and an electrical motor 12b, for example. In this case, the centrifugal multi-blade fan 12a is driven by the electrical motor 12b, and the rotational speed (air blowing amount) of the electrical motor 12b is controlled by a control voltage output from the air conditioning controller 60.

An evaporator 13 is disposed in the air conditioning casing 11 at a downstream air side of the blower 12 to cross all the air passage area in the air conditioning casing 11. The evaporator 13 is a cooling heat exchanger in which the refrigerant passing therein is heat-exchanged with air blown by the blower 12 to cool the blown air. The evaporator 12 is one component in a refrigerant cycle. The refrigerant cycle includes a compressor, a condenser, a gas-liquid separator and an expansion valve, in addition to the evaporator 13, which are generally known.

At a downstream air side of the evaporator 13, the air passage of the casing 31 is provided with a first air passage 16 through which air after passing through the evaporator 13 flows, a second air passage 17 used as a cool air bypass passage through which air after passing through the evaporator 13 flows while bypassing the first and second heater core 14, 15, and a mixing space 18 in which air from the first air passage 16 and air from the second air passage 17 are mixed.

In the first air passage 16, the first and second heater cores 14 and 15 are arranged, so that air dehumidified and cooled by the evaporator 13 flows through the first and second heater cores 14 and 15 in this order through the first air passage 16. The first heater core 14 is a first heating heat exchanger configured to perform heat exchange between engine coolant (hot water) heated by heat of the vehicle engine EG and air after passing through the evaporator 13. Thus, the first heat core 14 heats air after passing through the evaporator 13 in the first air passage 16. The second heater core 15 is a second heating heat exchanger configured to perform heat exchange between engine coolant (hot water) and air after passing through the first heater core 14. Thus, the second heat core 15 heats air after passing through the first heater core 14 in the first air passage 16. For example, the engine coolant is water, or a water solution including an addition component.

Specifically, a coolant circuit 30 is provided, so that coolant is circulated between the first and second heater cores 14, 15 and the engine EG via the coolant circuit 30. The coolant circuit 30 is provided with a first coolant passage 31 used for the first and second heater cores 14, 15, and a second coolant passage 32 used for a radiator 41. The first and second coolant passages 31, 32 are connected to the engine EG in parallel with respect to a flow of the coolant from the engine EG.

The coolant passage 31 for the first and second heater cores 14, 15 is provided with a branch point 31a, a join point 31b, and first and second coolant passages 33, 34. The coolant flowing out of the engine EG is branched at the branch portion 31a into the first coolant passage 33 and the second coolant passage 34, and is joined at the join point 31b. The first heater core 14 is located in the first coolant passage 33 so that the coolant flowing into the first coolant passage 33 flows through the first heater core 14. The second heater core 15 is located in the second coolant passage 34 so that the coolant flowing into the second coolant passage 34 flows through the second heater core 15. The coolant having passed through the first and second heater cores 14, 15 respectively is joined at the join point 31b. Thus, the first and second heater cores 14, 15 are arranged in parallel with respect to the flow of the engine coolant.

A thermostat 42 is located in the coolant circuit 30 at a coolant inlet side of the engine EG. A flow amount of the coolant flowing into the coolant passage 31 for the first and second heater cores 14, 15 and a flow amount of the coolant flowing into the coolant passage 32 for the radiator 41 are adjusted by the thermostat 42. An electrical water pump 43 is disposed in the coolant circuit 30 so that the coolant circulates in the coolant circuit 30. The water pump 43 is controlled by the air conditioning controller 60 such that the water pump 43 is operated even when the engine EG is stopped. The water pump 43 may be operated by the power from the engine EG. In this case, the water pump 43 is also stopped when the engine EG stops.

A first coolant temperature sensor 65 is located at a coolant outlet side of the engine EG, to detect the temperature of the coolant flowing out of the engine EG. A second coolant temperature sensor 66 is located to detect the temperature of the coolant having passed through an inlet side portion 151a of the tube 151 in the second heater core 15.

FIG. 2 is a perspective view showing first and second heater cores 14, 15 arranged in the first air passage 16 of the casing 11 in this order in the air flow direction.

As shown in FIG. 2, the first heater core 14 includes a plurality of tubes 141 arranged in parallel with each other, a first header tank 142 connected to at one end side of the plurality of tubes in a tube longitudinal direction, a second header tank 143 arranged at the other end side of the plurality of tubes 141 in the tube longitudinal direction, and fins 144 attached to the outer surfaces of the tubes 141 so as to facilitate heat exchange between the coolant and air. A pipe connection portion 145 is provided at a coolant inlet side of the first heater core 14 to be connected to the first header tank 142, and a pipe connection portion 146 is provided at a coolant outlet side of the first heater core 14 to be connected to the second header tank 143. Therefore, coolant flowing from the pipe connection portion 145 into the first header tank 142 is distributed into the tubes 141 from the first header tank 142, and the coolant after passing through the tubes 141 is joined in the second header tank 143 and then flows out of the pipe connection portion 146 that is provided at the coolant outlet side of the first heater core 14. The plural tubes 141 and the plural fins 142 are alternately stacked in a stack direction that is parallel to the longitudinal direction of the header tanks 142, 143, thereby forming a heat exchanging portion in which air blown by the blower 12 is heat-exchanged with the coolant.

As shown in FIG. 2, the height dimension of the entire second heater core 15 is made lower than the height dimension of the entire first heater core 14. In the example of FIG. 2, both the first and second heater cores 14, 15 are arranged on the same surface of the casing 11, and the height dimension of the second heater core 15 is set about half of the height dimension of the first heater core 14. The height dimension of the second heater core 15 may be suitably changed with respect to the height dimension of the first heater core 14, without being limited to the example shown in FIG. 2.

Thus, the flow resistance of the coolant flowing through the second heater core 15 can be made larger than the flow resistance of the coolant flowing through the first heater core 14, and thereby the flow amount of the coolant flowing through the second heater core 15 can be made smaller than the flow amount of the coolant flowing through the first heater core 14. For example, the passage sectional area of the second coolant passage 34 of the second heater core 15 is set smaller than the passage sectional area of the first coolant passage 33 of the first heater core 14. More specifically, the flow resistance of the coolant flowing through the second coolant passage 34 of the second heater core 15 is made larger than the flow resistance of the coolant flowing through the first coolant passage 33 of the first heater core 14, and thereby the flow amount of the coolant flowing through the second heater core 15 is made smaller than the flow amount of the coolant flowing through the first heater core 14.

The second heater core 15 is a heat exchanger in which a single flat tube 151 is arranged in meandering to have a serpentine shape. Furthermore, fines 152 are provided in the spaces between adjacent tubes 151.

The tube 151 is made of metal such as Cu or Al, and is formed to define a coolant passage therein. The fins 152 are made of metal such as Cu or Al, and are formed to facilitate heat exchange between air and coolant. The single tube 151 is bent in meandering to have plural tube parts that are stacked alternately with the fins 152 in a stack direction and are made to contact the fins 152 in the stack direction. The tube 151 is folded around the fins 152, thereby forming a heat exchanging portion in which air blown by the blower 12 and having passed through the first heater core 14 is heat-exchanged with the coolant. The tube 151 is provided with tube parts 151b, 151d that are provided without contacting the fins 152 to define a coolant passage through which the coolant flows to a coolant outlet of the second heater core 15.

In the present embodiment, the coolant passage of the second heater core 15 is formed separately from the first heater core 14. An inlet-side pipe connection portion 153 is connected to one end side of the tube 151, and an outlet-side pipe connection portion 154 is connected to the other end side of the tube 151. The pipe connection portions 153, 154 are connected to a piping that defines the coolant passage between the engine and the second heater core 15. Thus, the inlet-side pipe connection portion 153 is adapted as a coolant inlet of the second heater core 15, and the outlet-side pipe connection portion 154 is adopted as a coolant outlet of the second heater core 15. As shown in FIGS. 2 and 3, the inlet-side pipe connection portion 153 and outlet-side pipe connection portion 154 are arranged adjacent to each other.

In the present embodiment, the second heater core 15 is arranged in a lower half area of the first air passage 16, the inlet-side pipe connection portion 153 is arranged at a bottom portion of the second heater core 15, and the outlet-side pipe connection portion 154 is arranged at a lower side of the inlet-side pipe connection portion 153. The tube 151 is folded from the lower side of the second heater core 15 to have plural folded parts.

In the present embodiment, the fin 152 is a corrugated fin bent in a wave shape. In the example of FIG. 2, the corrugated fins 152 are configured, such that the fin pitch fp1 of the fins 152 in a high temperature area that is at an upstream side of the coolant flow is relatively large, and the fin pitch fp2 of the fins 152 in a low temperature area that is a downstream side of the coolant flow is relatively small. Here, the fin pitch Fp1, Fp2 is a distance between adjacent fin ridges protruding on the same side.

FIG. 3 is a schematic diagram showing a configuration of the second heater core 15 when being viewed from a downstream air side of the second heater core 15.

In FIGS. 2 and 3, the inlet side portion 151a positioned at the coolant inlet side of the tube 151 and the outlet side portion 151b positioned at the coolant outlet side of the tube 151 are arranged adjacent to each other. In the present embodiment, the entire outer shape of the second heater core 15 is formed approximately in a rectangular shape, the inlet side portion 151a extends straightly at a bottom portion in the rectangular shape, and the outlet side portion 151b extends straightly at a lower side of the inlet side portion 151a. The inlet side portion 151a and the outlet side portion 151b are arranged approximately in parallel with each other.

The coolant after flowing into the inlet side portion 151a of the tube 151 passes through the folded tube parts of the tube 151 as in the chain line arrows of FIG. 3 to be heat-exchanged with air, and then flows into the outlet side portion 151b. Thus, the inlet side portion 151a of the tube 151 can be adapted as a coolant tube part before being heat-exchanged, and the outlet side portion 151b of the tube 151 can be adapted as a coolant tube part after being heat-exchanged. The flow direction of the coolant flowing through the outlet side portion 151b of the tube 151 is opposite to the flow direction of the coolant flowing through the inlet side portion 151a of the tube 151.

Furthermore, the Peltier module 50 is arranged and inserted between the inlet side portion 151a and the outlet side portion 151b of the tube 151.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3. The Peltier module 50 includes a plurality of Peltier elements 51, which are formed integrally. When electrical current flows through the Peltier element 51, heat is moved from one side of the Peltier elements 51 to the other side of the Peltier elements 51, thereby pumping heat. The moving direction of the heat in the Peltier elements 51 is determined based on the flow direction of the electrical current.

Specifically, Peltier element 51 is provided with a P-type layer 52, an N-type layer 53, an electrode 54 electrically connected to one P-type layer 52 and one N-type layer 53 at one end side, and an electrode 55 electrically connected to the one N-type layer 53 and an another P-type layer 52 at the other end side. The P-type layer 52 and the N-type layer 53 are made of a semiconductor or a metal, etc., and the electrodes 54 and 55 are made of metal, which are generally known.

In the Peltier module 50, the plural Peltier elements 51 are connected in series, and the Peltier elements 51 arranged in a straight line are placed between a pair of insulation layers 56, 57. The insulation layers 56 and 57 are plate shapes, and are made of ceramics or the like. In the present embodiment, electrical current is supplied to the electrodes 54, 55, such that the one side insulation layer 56 at a side of the inlet side portion 151a of the tube 151 is used as a heat radiation plate, and the other side insulation layer 57 at a side of the outlet side portion 151b of the tube 151 is used as a heat absorption plate. The Peltier element 51 of the Peltier module 50 is electrically turned on or off based on a control signal outputted from the air conditioning controller 60.

In the present embodiment, the inlet side portion 151a of the tube 151 is provided with an open portion 161, and the open portion 161 is closed by the heat-radiation insulation layer 56 of the Peltier module 50. Thus, the coolant passage of the inlet side portion 151a of the tube 151 is defined by a metal plate member and the heat-radiation insulation layer 56, so that heat is radiated directly to the coolant from a heat-radiation surface 56a of the heat-radiation insulation layer 56.

Similarly, the outlet side portion 151b of the tube 151 is provided with an open portion 162, and the open portion 162 is closed by the heat-absorption insulation layer 57 of the Peltier module 50. Thus, the coolant passage of the outlet side portion 151b of the tube 151 is defined by a metal plate member and the heat-absorption insulation layer 57, so that heat is absorbed directly from the coolant by a heat-absorption surface 57a of the heat-absorption insulation layer 57.

The inlet side portion 151a and the outlet side portion 151b of the tube 151 are configured such that the height of the coolant passage inside of the inlet side portion 151a and the outlet side portion 151b is smaller than 1 mm. More specifically, the height of the coolant passage inside of the inlet side portion 151a and the outlet side portion 151b is set in a range smaller than 1 mm and larger than 1 μm (e.g., some μm). Here, the height of the coolant passage inside of the inlet side portion 151a is a height in a direction perpendicular to the surfaces of the insulation layers 56, 57 of the Peltier module 50.

On the other hand, as shown in FIG. 1, cool air having passed through the evaporator 13 flows into the mixing space 18 through the second air passage 17 used as the cool air bypass passage while bypassing the first and second heater cores 14 and 15. Thus, the temperature of air (i.e., conditioned air) mixed in the mixing space 18 is changed by adjusting a ratio between a flow amount of air passing through the first air passage 16 and a flow amount of air passing through the second air passage 17.

In the present embodiment, an air mix door 19 is located on a downstream air side of the evaporator 13 at an upstream air side of the first air passage 16 and the second air passage 17, and is configured to continuously change a ratio between a flow amount of air passing through the first air passage 16 and a flow amount of air passing through the second air passage 17.

The air mix door 19 is used as a temperature adjusting unit that adjusts the air temperature in the mixing space 18 so as to adjust the temperature of conditioned air to be blown into the vehicle compartment. The air mix door 19 is driven by an electrical actuator 72, and operation of the electrical actuator 72 for the air mix door 19 is controlled by a control signal output from the air conditioning controller 60.

Furthermore, at the most downstream air side, the casing 11 is provided with plural opening portions 24, 25, 26 from which conditioned air of the mixing space 18 is blown into the vehicle compartment that is a space to be air-conditioned. For example, the plural opening portions 24, 25, 26 include a defroster opening portion 24, a face opening portion 25 and a foot opening portion 26.

A defroster duct (not shown) is connected to the defroster opening portion 24, such that conditioned air is blown toward an inner surface of a front windshield of the vehicle from a defroster air outlet provided at a downstream end of the defroster duct. A face duct (not shown) is connected to the face opening portion 25, such that conditioned air is blown toward an upper side of a passenger in the vehicle compartment from a face air outlet provided at a downstream end of the face duct. A foot duct (not shown) is connected to the foot opening portion 26, such that conditioned air is blown toward a lower side of a passenger in the vehicle compartment from a foot air outlet provided at a downstream end of the foot duct.

Air outlet mode doors for selectively switching an air outlet mode are provided in the casing 11. The air outlet mode doors include a defroster door 24a for opening and closing the defroster opening portion 24, a face door 25a for opening and closing the face opening portion 25, and a foot door 26a for opening and closing the foot opening portion 26. The outlet mode doors 24a, 25a, 26a are driven by an electrical actuator 73, and operation of the electrical actuator 73 for the outlet mode doors 24a, 25a, 26a is controlled by a control signal output from the air conditioning controller 60.

The electric control portion of the present embodiment will be described with reference to FIG. 5. The air conditioning controller 60 includes a microcomputer and a circumference circuit. The microcomputer has CPU, ROM, RAM, etc. The air conditioning controller 60 performs various calculations and processes based on control programs stored in the ROM, and control operation of various equipments connected to output side of the air conditioning controller 60. For example, various air-conditioning control equipments such as the blower 12, various actuators 71, 72, 73 and Peltier element 51 are connected to the output side of the air conditioning controller 60.

Air conditioning sensor group is connected to an input side of the air conditioning controller 60. For example, the air conditioning sensor group includes an inside air sensor 61 configured to detect a temperature Tr of the vehicle compartment, an outside air temperature sensor 62 configured to detect an outside air temperature Tam , a solar sensor 63 configured to detect a solar radiation amount Ts of the vehicle compartment, an evaporator temperature sensor 64 configured to detect an air temperature TE blown from the evaporator 13, the first and second coolant temperature sensors 65, 66 for detecting the coolant temperature TW of the engine EG. The air temperature TE blown from the evaporator 13 corresponds to a refrigerant evaporation temperature in the evaporator 13.

An operation panel 70 is located near the instrument panel at the front portion of the vehicle compartment. The operation panel 70 is connected to the input side of the air conditioning controller 60, such that operation signals of various air-conditioning operation switches provided in the operation panel 70 are input to the air conditioning controller 60. The air-conditioning operation switches provided in the operation panel 70 include, for example, an operation switch (not shown) of the air conditioner 1, an air-conditioning switch 70a for selectively turning on or off of the compressor thereby turning on or off of the air conditioning operation in the air conditioner 1, an automatic switch 70b for setting or releasing an automatic control of the air conditioner 1, an operation mode selecting switch (not shown) for selecting an operation mode, a suction mode selecting switch (not shown) for selectively switching an air suction mode, an air outlet mode selecting switch (not shown) for selectively switching an air outlet mode, an air amount setting switch (not shown) for setting an air blowing amount of the blower 12, a temperature setting switch 70c for setting a temperature of the vehicle compartment, an economic switch 70d for outputting an economy priority mode in which the refrigerant cycle is operated with a priority of the power saving.

The air conditioning controller 60 is electrically connected to an engine controller 80 (ENGINE ECU) which controls operation of the engine EG. The air conditioning controller 60 and the engine controller 80 are configured to be capable of electrically communicating with each other. When a signal is input into one of the controllers, the other of the controllers can control the equipments connected to the output side based on the signal. For example, when the air conditioning controller 60 outputs an operation request signal to the engine controller 80, the engine controller 80 causes the engine EG to be operated.

Next, the operation of the present embodiment with the above configuration will be described with reference to FIG. 6. FIG. 6 is a flow diagram showing a control process performed by the air conditioning controller 60 in the first embodiment. The respective steps in FIG. 6 correspond to respective function portions provided in the air conditioning controller 60.

First, at step S1, initialization of a flag, a timer, a control variable, and an initial position setting of a stepping motor in respective electrical motors, and the like are performed.

At step S2, operation signals of the operation panel 70 and signals regarding the circumstances of the vehicle used for the air conditioning control, that is, detection signals from the above group of sensors 61 to 66 are read, and then the operation proceeds to step S3. Specifically, the operation signals include a vehicle interior setting temperature Tset set by the vehicle interior temperature setting switch 70c, a selection signal of the air outlet mode, a selection signal of the air suction mode, a setting signal of the amount of air blown by the blower 12, and the like.

At step S3, a target outlet air temperature TAO of blown air into the vehicle compartment is calculated. The target outlet air temperature TAO of blown air into the vehicle compartment is calculated based on the vehicle interior setting temperature Tset and the vehicle environment condition such as the inside air temperature, by using the following formula F1.

TAO=Kset×Tset−Kr×Tr−Kam×Tam−Ks×Ts+C  (F1)

where Tset is a vehicle interior setting temperature set by the vehicle interior temperature setting switch 70c, Tr is an inside air temperature detected by the inside air sensor 61, Tam is an outside air temperature detected by the outside air sensor 62, and Ts is an amount of solar radiation detected by the solar radiation sensor 63. Furthermore, Kset, Kr, Kam and Ks are gains, and C is a constant value for a correction.

Next, at step S4, control target values of the various equipments connected to the output side of the air conditioning controller 60 are determined. For example, an air blowing amount (blower level) of the blower 12, the air suction mode, the air outlet mode, the open degree of the air mix door 19, the engine operation request signal and ON/OFF operation of the Peltier elements 51 and the like are determined. The air blowing amount and the air outlet mode and the like are determined based on the target outlet air temperature TAO. Furthermore, the air conditioning controller 60 determines whether the engine operation request signal is output or not based on the engine coolant temperature TW. For example, when the engine coolant temperature TW detected by the first coolant temperature sensor 65 is lower than a predetermined temperature TW1, the air conditioning controller 60 outputs the engine operation request signal to the engine EG. Next, the ON/Off operation determination of the Peltier elements 51 will be described.

Then, at step S5, control signals are output from the air conditioning controller 60 to various air-conditioning control equipments or the engine controller 80, such that the control target values determined at step S4 can be obtained.

Thus, the blower 12 is operated to have a predetermined air blowing amount, the air outlet mode doors are positioned to set a desired air outlet mode, and the engine EG is operated in accordance with the engine operation request signal output from the air conditioning controller 60.

Next, at step S6, it is determined whether a control time period i elapses. When it is determined that the control time period i elapses at step S6, the control program returns to step S2.

Next, the control process of step S4 for determining the ON/OFF operation of the Peltier element 51 will be described in detail. FIG. 7 is a flowchart for determining ON/OFF operation of the Peltier element 51, according to the present embodiment.

At step S11, an air temperature TWD blown from the second heater core 15 is calculated. The air temperature TWD is a heated temperature of air heated by the engine coolant at least at the second heater core 15. The air temperature TWD can be calculated by the coolant temperature TW2 detected by the second coolant temperature sensor 66, the air temperature TE after passing through the evaporator 13 and the heat exchange capacity of the heater core 15 and the like. Generally, the air temperature TWD blown out of the second heater core 15 is approximately equal to the coolant temperature TW2 detected by the second coolant temperature sensor 66. However, an air temperature sensor for detecting the temperature of air blown from the second heater core 15 may be used instead of the second coolant temperature sensor 66.

Next, at step S12, the air temperature TWD blown from the second heater core 15 is compared with the target outlet air temperature TAO. When the air temperature TWD is lower than the target outlet air temperature TAO at step S12, the Peltier element 51 is turned on at step S13. When the air temperature TWD is not lower than the target outlet air temperature TAO at step S12, the Peltier element 51 is turned off at step S14.

For example, when a long time elapses after the engine EG stops, the coolant temperature may become lower, and thereby the air temperature TWD may become lower than the target outlet air temperature TAO. In this case, in the present embodiment, electrical power is supplied to the Peltier element 51, such that heat is absorbed from the coolant after passing through the second heater core 15, and heat is radiated to the coolant before being heat-exchanged in the second heater core 15. Thus, the temperature of the coolant before being heat-exchanged and flowing into the second heater core 15 is increased to a temperature required for the heating of the vehicle compartment. In this case, it is prefer to set the air mix door 19 at the maximum heating position, by the air conditioning controller 60.

When the engine EG is operated or an elapsed time after the stop of the engine EG is shorter, the coolant temperature is sufficiently high. In this case, if the air temperature TWD is equal to or higher than the target outlet air temperature TAO, it is unnecessary to heat the engine coolant by using the operation of the Peltier element 51. In this case, the Peltier element 51 is not turned on by the air conditioning controller 60. In this case, the position (open degree) of the air mix degree 19 is controlled by the air conditioning controller 60, thereby adjusting the temperature of conditioned air blown into the vehicle compartment.

The operation effects of the first embodiment will be described.

(1) when the Peltier element 51 is not provided, the coolant flowing out of the second heater core 15 flows simply into the engine EG. In this case, the heat quantity without being heat-exchanged with air in the second heater core 15 may be radiated from the surface of the engine EG.

In contrast, according to the present embodiment, because the heat is pumped from the coolant flowing out of the second heater core 15 to the coolant before being heat-exchanged in the second heater core 15 by using the Peltier element 51, the heat quantity without being heat exchanged with air in the second heater core 15 can be further used for the heating of the vehicle compartment. Thus, the heat quantity of the engine coolant can be effectively used for the heating.

(2) In the present embodiment, the Peltier module 50 including the Peltier element 51 is arranged between the inlet side portion 151a of the tube 151 of the second heater core 15 and the outlet side portion 151b of the tube 151 of the second heater core 15.

That is, the Peltier element 51 is inserted between the inlet side portion 151a of the tube 151 and the outlet side portion 151b of the tube 151. Thus, the inlet side portion 151a of the tube 151 can be used as a heat radiation portion which radiates heat from the Peltier element 51 to the coolant, and the outlet side portion 151b of the tube 151 can be used as a heat absorption portion which absorbs heat from the coolant to the Peltier element 51. In the present embodiment, the heat radiation portion as the inlet side portion 151a, the Peltier element 51, and the heat absorption portion as the outlet side portion 151b can be formed integrally.

FIG. 20 is a comparison example of a vehicle air conditioner 1 performed by the inventors of the present application. In FIG. 20, parts similar to or corresponding to those of FIG. 1 are indicated by the same reference numbers.

The air conditioner 1 shown in FIG. 20 is provided the first and second heater cores 14, 15, similarly to the example of FIG. 1. Furthermore, a heat radiation portion 34a is provided in the coolant passage 34 at an upstream side of the second heater core 15, and a heat absorption portion 34b is provided in the coolant passage 34 at a downstream side of the second heater core 15. Furthermore, a Peltier module 50 is arranged between the heat radiation portion 34a and the heat absorption portion 34b. The Peltier module 50, the heat radiation portion 34a and the heat absorption portion 34b are combined as a single component, and are disposed in the engine compartment outside of the casing 11.

In the vehicle air conditioner 1 shown in FIG. 20, heat is pumped and moved by using the Peltier element of the Peltier module 50 from the coolant flowing in the heat absorption portion 34b to the coolant flowing in the heat radiation portion 34a. Therefore, heat of the coolant without being heat-exchanged with air in the second heater core 15 can be effectively used for the heating.

However, in the vehicle air conditioner 1 shown in FIG. 20, because the Peltier element 50, the heat radiation portion 34a and the heat absorption portion 34b are arranged outside of the casing 11, a part of the heat radiated from the Peltier element cannot be effectively used, thereby causing heat radiation loss.

In this case, the heat loss cannot be transmitted to the coolant in the heat radiation portion 34a.

Furthermore, in the comparison example of the vehicle air conditioner 1 shown in FIG. 20, because the Peltier module 50, the heat radiation portion 34a and the heat absorption portion 34b are configured separately from the casing 11, it is necessary to mount the Peltier module 50, the heat radiation portion 34a and the heat absorption portion 34b to the vehicle, separately from the casing 11.

In the comparison example of the vehicle air conditioner 1 shown in FIG. 20, because the heat radiation portion 34a is arranged outside of the casing 11, heat loss may be caused from the heat radiation portion 34a, or heat loss is caused from the coolant while flowing from the heat radiation portion 34a outside of the casing 11 to the second heater core 15.

In contrast, in the first embodiment shown in FIG. 1, the heat radiation portion 151a, the Peltier module 50 and the heat absorption portion 151b are integrated with the second heater core 15, and thereby the heat radiation portion 151a can be arranged inside of the first air passage 16. Thus, according to the present embodiment, the heat radiation amount of the Peltier element 51 can be effectively used for the heating of the air blown toward the vehicle compartment.

Furthermore, the heat radiation portion as the inlet side portion 151a of the tube 151, the Peltier module 50 and the heat absorption portion as the outlet side portion 151b of the tube 151 are integrated with the second heater core 15. Therefore, the heat radiation portion 151a, the Peltier module 50 and the heat absorption portion 151b can be easily mounted to the vehicle together with the casing 11. For example, it is unnecessary for the Peltier module 50 to be mounted in an engine compartment, thereby improving mounting performance.

(3) In the present embodiment, the inlet side portion 151a of the tube 151 is used as a part of a heat-exchanging core portion in which the coolant is heat-exchanged with air. That is, a part of the tube 151 that configuring the heat-exchanging core portion is used as the heat radiation portion.

The fin 152 is also provided on the outer surface of the inlet side portion 151a of the tube 151, used as the heat radiation portion. Therefore, heat of the coolant flowing through the inlet side portion 151a as the heat radiation portion can be easily transmitted to air, thereby reducing the temperature of the heat absorption side of the Peltier element 51.

When the temperature difference between the heat absorption side and the heat radiation side is too enlarged, the performance of the Peltier element 51 is decreased.

In the present embodiment, because the heat pumped from the Peltier element 51 can be quickly transmitted to air, it can prevent temperature increase of the coolant flowing through the inlet side portion 151a of the tube 151, thereby preventing a decrease in the performance of the Peltier element 51.

Thus, it is possible to facilitate the transmission of the heat radiated from the Peltier element 51 to air.

The lower surface of the outlet side portion 151b of the tube 151, as the heat absorption portion, is abutted to the wall surface of the casing 11, and the upper surface of the outlet side portion 151b of the tube 151, as the heat absorption portion, is abutted to the Peltier module 50. Therefore, it can effectively restrict the outlet side portion 151b of the tube 151, as the heat absorption portion, from being exposed to the air to be blown into the vehicle compartment. Thus, it can prevent the air from being cooled by the coolant flowing through the outlet side portion of the tube 151.

In the present embodiment, the passage height of the inlet side portion 151a and the outlet side portion 151b of the tube 151, defining the heat radiation portion and the heat absorption portion, is set in a range of some-pm size smaller than 1 mm. Therefore, the coolant passage of the heat radiation portion and the heat absorption portion can be made as in a micro channel. Thus, it is possible to cause a turbulent flow in the coolant passage, thereby improving heat transmission efficiency of the coolant in the heat radiation portion and the heat absorption portion.

More preferably, the passage height of the inlet side portion 151a and the outlet side portion 151b of the tube 151 is set in a range from 0.2 mm to 0.85 mm. In this case, the heat transmission efficiency of the coolant in the inlet side portion 151 a as the heat radiation portion and in the outlet side portion 151b as the heat absorption portion can be more increased.

FIG. 8 is a graph showing the relationship between the passage height of the tube 151 and the heat transmission efficiency. The heat transmission efficiency of the tube 151 is calculated by using a generally know method, in a case where the passage width of the tube 151 is set at 10 mm. As shown in FIG. 8, the heat transmission efficiency is gradually decreased as the passage height becomes higher. When the passage height of the tube 151 becomes equal to or higher than 0.85 mm, the heat transmission efficiency is rapidly decreased. When the passage height of the tube 151 is smaller than 0.20 mm, pressure loss in the tube 151 may be increased.

Second Embodiment

A second embodiment of the present invention will be described with reference to FIG. 9. FIG. 9 shows a second heater core 15 according to the second embodiment.

In the above-described first embodiment, the second heater core 15 is configured such that the coolant passage of the tube 151 from the inlet side portion 151a to the outlet side portion 151b is formed in meandering.

In contrast, in the second embodiment, the tube 151 including the inlet side portion 151 and the outlet side portion 151b are configured, such that the coolant flowing into the inlet side portion 151a of the tube 151 is branched into plural passages of plural tube parts 151m extending straightly upwardly, and is joined to flow into the outlet side portion 151b as in the chain line arrows of FIG. 9. The tube parts 151m are arranged in parallel, in a direction perpendicular to the extension direction of the inlet side portion 151a and the outlet side portion 151b. On end sides of the plural tube parts 151m are connected to the inlet side portion 151a to communicate with the inlet side portion 151a, and the other end sides of the plural tube parts 151m are joined in a join portion 151n, and the join portion 151n is connected to the outlet side portion 151b of the tube 151 to communicate with the outlet side portion 151b.

That is, the coolant flow passage between the inlet side portion 151a as the heat radiation portion of the Peltier element and the outlet side portion 151b as the heat adsorption portion of the Peltier element can be arbitrarily changed based on heat exchanging capacity or the flow amount of the coolant of the second heat core 150.

In a case where the flow amount of the coolant flowing through the second heater core 15 is smaller than that of the first heater core 14, the tube 151 is preferably formed into a serpentine shape similarly to the first embodiment. In this case, a temperature distribution in air blown from the second heater core 15 can be made smaller, and thereby the temperature of air blown from the second heater core 15 can be made in uniform. In the second embodiment, because the coolant flows through the tube parts 151m in one way, a temperature difference may be caused. However, in this case, the pressure loss in the tube 151 can be reduced, thereby increasing the flow amount of the coolant flowing into the tube 151. In the second embodiment, the other parts of the second embodiment are similar to those of the above-described first embodiment.

Third Embodiment

A third embodiment will be described with reference to FIG. 10. FIG. 10 shows a second heater core 15 according to the third embodiment. In the third embodiment, the arrangement range of the Peltier module 50 is enlarged as compared with the above-described first embodiment.

More specifically, as shown in FIG. 10, an inlet side portion of the tube 151 as the heat radiation portion is configured by two straight inlet side portions 151a, 151c that are connected perpendicularly. The inlet side portion 151a positioned upstream of the inlet side portion 151c in the coolant flow direction is arranged at the bottom portion in the entire rectangular shape of the heater core 15, and the inlet side portion 151c positioned downstream of the inlet side portion 151a in the coolant flow direction is arranged at one side portion of the entire rectangular shape of the heater core 15. Similarly, as shown in FIG. 10, an outlet side portion of the tube 151 as the heat absorption portion is configured by two straight inlet side portions 151b, 151d that are connected perpendicularly. The outlet side portion 151b positioned downstream of the outlet side portion 151d in the coolant flow direction is arranged at the bottom portion in the entire rectangular shape of the heater core 15, and the outlet side portion 151d positioned upstream of the outlet side portion 151b in the coolant flow direction is arranged at the one side portion of the entire rectangular shape of the heater core 15.

Furthermore, in the second heater core 15 shown in FIG. 10, two plate-shaped Peltier modules 50 are arranged in 1 L-shape between the inlet side portions 151a, 151c of the tube 151 as the heat radiation portion, and the outlet side portion 151b, 151d of the tube 151 as the heat absorption portion. In the above-described third embodiment, the other parts are similar to those of the above-described first embodiment.

Fourth Embodiment

A fourth embodiment of the present invention will be described with reference to FIG. 11. FIG. 11 shows a second heater core 15 according to the fourth embodiment. In the fourth embodiment, the arrangement range of the Peltier module 50 is further enlarged as compared with the above-described third embodiment.

More specifically, as shown in FIG. 11, an inlet side portion of the tube 151 as the heat radiation portion is configured by three straight inlet side portions 151a, 151c, 151e that are connected in this order. The inlet side portion 151a positioned most upstream of the inlet side portion 151c in the coolant flow direction is arranged at the bottom portion in the entire rectangular shape of the heater core 15, the inlet side portion 151c positioned downstream of the inlet side portion 151a in the coolant flow direction is arranged at one side portion of the entire rectangular shape of the heater core 15, and the inlet side portion 151e positioned downstream of the inlet side portion 151c in the coolant flow direction is arranged at the top side portion of the entire rectangular shape of the heater core 15. Similarly, as shown in FIG. 11, an outlet side portion of the tube 151 as the heat absorption portion is configured by three straight outlet side portions 151b, 151d, 151f that are connected in this order. The outlet side portion 151b positioned most downstream in the coolant flow direction is arranged at the bottom portion in the entire rectangular shape of the heater core 15, the outlet side portion 151d positioned upstream of the outlet side portion 151b in the coolant flow direction is arranged at the one side portion of the entire rectangular shape of the heater core 15, and the outlet side portion 151f positioned upstream of the outlet side portion 151d in the coolant flow direction is arranged at the top side portion of the entire rectangular shape of the heater core 15

Furthermore, in the second heater core 15 shown in FIG. 10, three plate-shaped Peltier modules 50 are arranged in a U-shape between the inlet side portions 151a, 151c, 151f of the tube 151 as the heat radiation portion, and the outlet side portion 151b, 151d, 151f of the tube 151 as the heat absorption portion. In the above-described fourth embodiment, the other parts are similar to those of the above-described first embodiment.

Fifth Embodiment

A fifth embodiment of the present invention will be described with reference to FIG. 12. FIG. 12 shows a second heater core 15 according to the fifth embodiment. In the fifth embodiment, the arrangement range of the Peltier module 50 is further enlarged as compared with the above-described fourth embodiment.

More specifically, as shown in FIG. 12, an inlet side portion of the tube 151 as the heat radiation portion is configured by four straight inlet side portions 151a, 151c, 151e, 151g that are connected in this order. The inlet side portion 151a positioned most upstream in the coolant flow direction is arranged at the bottom portion in the entire rectangular shape of the second heater core 15, the inlet side portion 151c positioned downstream of the inlet side portion 151a in the coolant flow direction is arranged at one side portion of the entire rectangular shape of the heater core 15, the inlet side portion 151e positioned downstream of the inlet side portion 151c in the coolant flow direction is arranged at the top side portion of the entire rectangular shape of the heater core 15, and the inlet side portion 151g positioned downstream of the inlet side portion 151e in the coolant flow direction is arranged at the other one side portion of the entire rectangular shape of the heater core 15. Similarly, as shown in FIG. 12, an outlet side portion of the tube 151 as the heat absorption portion is configured by four straight inlet side portions 151b, 151d, 151f, 151h that are connected in this order. The outlet side portion 151b positioned most downstream in the coolant flow direction is arranged at the bottom portion in the entire rectangular shape of the heater core 15, the outlet side portion 151d positioned upstream of the outlet side portion 151b in the coolant flow direction is arranged at the one side portion of the entire rectangular shape of the heater core 15, the outlet side portion 151f positioned upstream of the outlet side portion 151d in the coolant flow direction is arranged at the top side portion of the entire rectangular shape of the heater core 15, and the outlet side portion 151h positioned upstream of the outlet side portion 151f in the coolant flow direction is arranged at the other one side portion of the entire rectangular shape of the heater core 15.

Furthermore, in the second heater core 15 shown in FIG. 12, four plate-shaped Peltier modules 50 are arranged in a part of the rectangular shape between the inlet side portions 151a, 151c, 151e, 151g of the tube 151 as the heat radiation portion, and the outlet side portion 151b, 151d, 151f, 151h of the tube 151 as the heat absorption portion. In the above-described third embodiment, the other parts are similar to those of the above-described first embodiment.

Sixth Embodiment

A sixth embodiment of the present invention will be described with reference to FIG. 13. FIG. 13 is a perspective view showing first and second heater cores 14, 15 according to the sixth embodiment of the present invention. In the sixth embodiment, as shown in FIG. 13, the outlet side portion 151b of the tube 151 is arranged outside of the first air passage 16, with respect to the second heater core 15 shown in FIG. 2 described in the first embodiment.

More specifically, an opening portion penetrating through a wall portion of the casing 11 is provided, and the outlet side portion 151b of the tube 151 is fixed to the casing 11 in a state that the outlet side portion 151b is arranged in the opening portion of the casing 11.

Instead of the opening portion, a recess portion recessed in the inner wall surface of the casing 11 may be provided such that the outlet side portion 151b is arranged in the recess portion. In the present embodiment, the inlet side portion 151a of the tube 151 and the Peltier module 50 are arranged above the wall surface of the casing 11 defining the first air passage 16, while the outlet side portion 151b of the tube 151 is not arranged in the first air passage 16 of the casing 11.

Because the outlet side portion 151b of the tube 151 is not exposed in the air flowing through the first air passage 16, it can prevent the air passing through the first air passage 16 from being re-cooled by the coolant in which heat has been absorbed.

In the present embodiment, the heat radiation portion 151a, the Peltier module 50 and the heat absorption portion 151b are integrated with the second heater core 15, thereby improving the mounting performance in the vehicle. In the above-described sixth embodiment, the other parts are similar to those of the above-described first embodiment.

Seventh Embodiment

A seventh embodiment of the present invention will be described with reference to FIG. 14. FIG. 14 is a perspective view showing first and second heater cores 14, 15 according to the seventh embodiment of the present invention. In the seventh embodiment, the first heater core 14 and the second heater core 15 are fixed to each other by using a connection member.

As shown in FIG. 14, a pipe connection portion 153 at the coolant inlet side of the second heater core 15 is made to communicate with a pipe connection portion 145 at the coolant inlet side of the first heater core 14, and a pipe connection portion 154 at the coolant outlet side of the second heater core 15 is made to communicate with a pipe connection portion 146 at the coolant outlet side of the first heater core 14, with respect to the arrangement of the first and second heater cores 14, 15 shown in FIG. 2. Therefore, a single coolant inlet is provided in the pipe connection portion 145 for both the first and second heater cores 14, 15, and a single coolant outlet is provided in the pipe connection portion 146 for both the first and second heater cores 14, 15. The coolant from the single coolant inlet of the pipe connection portion 145 is branched into first and second coolant streams flowing to respectively the first heater core 14 and the second heater core 15. Furthermore, the coolant flowing from both the first heater core 14 and the second heater core 15 are joined and flows out of the single coolant outlet of the pipe connection portion 146.

In the prevent embodiment, the number of the pipe connection portions can be reduced, thereby reducing the pipe connection steps, as compared with the above described first embodiment. In the above-described seventh embodiment, the other parts are similar to those of the above-described first embodiment.

Eighth Embodiment

An eighth embodiment of the present invention will be described with reference to FIG. 15. FIG. 15 is a schematic perspective view showing first and second heater cores 14, 15 according to the eighth embodiment of the present invention. In the eighth embodiment, a communication portion communicating with the coolant outlet 147 of the first heater core 14 is provided with respect to the second heater core 15 of FIG. 2 described in the first embodiment, such that the coolant flowing out of the first heater core 14 is joined with the coolant flowing in the outlet side portion 151b of the tube 151 of the second heater core 15.

Thus, when the temperature of the coolant flowing out of the first heater core 14 is higher than the temperature of the coolant after being heat-exchanged in the second heater core 15, the temperature of the coolant flowing through the outlet side portion 151 of the tube 151 can be increased, thereby reducing the temperature difference between the coolant flowing through the inlet side portion 151a of the tube 151 and the coolant flowing through the outlet side portion 151b of the tube 151.

Generally, the heat radiation amount of the Peltier element 51 becomes relatively larger, as a temperature difference between the heat absorbing side and the heat radiating side of the Peltier element 53 is smaller. Thus, according to the present embodiment, it is possible to make the heat radiation amount of the Peltier element 51 to be larger, and thereby it is possible to increase the temperature of the coolant flowing through the inlet side portion 151a of the tube 151.

The position of the communication portion 155 provided in the second heater core 15 may be suitably changed only if the coolant from the first heater core 14 is joined with the coolant of the tube 151 before being heat-absorbed by the Peltier element 51. For example, the communication portion 155 may be provided in any position (e.g., a middle position, a position upstream of the middle position) of the outlet side portion 151b of the tube 151. In the above-described sixth embodiment, the other parts are similar to those of the above-described first embodiment.

Ninth Embodiment

A ninth embodiment of the present invention will be described with reference to FIG. 16. FIG. 16 is a schematic diagram showing an air conditioner 1 for a vehicle according to the ninth embodiment of the present invention. In the air conditioner 1 according to any one of the above-described first to eighth embodiments, two heater cores such as the first and second heater cores 14, 15 are disposed. In the air conditioner 1 of the present embodiment, a single heater core 15 is disposed to heat air to be blown into the vehicle compartment. In the present embodiment, the heater core 14 described in the first embodiment is deleted in the air conditioner 1. Thus, the coolant circuit for the heater core 14 is also deleted.

In the present embodiment, the present invention can be suitably used for an air conditioner with a single heater core. In the above-described ninth embodiment, the other parts are similar to those of any one of the above-described first to eighth embodiments.

Tenth Embodiment

A tenth embodiment of the present invention will be described with reference to FIG. 17. FIG. 17 is a schematic diagram showing an air conditioner 1 for a vehicle according to the tenth embodiment of the present invention. In the above-described embodiments, the single engine cooling system is provided for the first and second heater cores 14, 15. Thus, when the first and second heater cores 14, 15 are provided, the cooling water from the single engine cooling system is branched to flow into the first and second heater cores 14, 15. In the tenth embodiment, two engine cooling systems are provided so that the coolant from the two engine cooling systems respectively flows into the first and second heater cores 14, 15.

For example, in a case where a cooling circuit for a cylinder head (CH) of an engine EG and a cooling circuit for a cylinder block (CB) of the engine EG are respectively provided in a vehicle, coolant flowing out of the cylinder head 101 flows into the first heater core 14, and the coolant flowing through the cylinder block 102 flows into the second heater core 15.

In a stationary operation of the engine EG, because the flow amount of the coolant flowing in the cylinder head 101 becomes larger than the flow amount of the coolant in the cylinder block 102, the temperature of the coolant flowing out of the cylinder head 101 becomes lower than the temperature of the coolant flowing out of the cylinder block 102. In this case, the cylinder head 101 can be preferentially cooled, thereby reducing knock. The coolant flowing out of the cylinder block 102 has a temperature higher than the temperature of the coolant flowing out of the cylinder block 101, thereby effectively performing the heating operation while it can prevent a friction increase in the engine EG.

Because the temperature of the coolant flowing into the second heater core 15 is higher than the temperature of the coolant flowing into the first heater core 14, heat exchanging efficiency can be improved in both the heater cores 14, 15. In the above-described tenth embodiment, the other parts are similar to those of the above-described first embodiment.

Eleventh Embodiment

An eleventh embodiment of the present invention will be described with reference to FIG. 18. FIG. 18 is a schematic diagram showing an air conditioner 1 for a vehicle according to the eleventh embodiment of the present invention. In the above-described embodiments, the coolant of the engine EG is used as the heating fluid flowing through the heater core(s). In the eleventh embodiment, a coolant of an inverter 111 is also used as a heating fluid for heating air.

The inverter 111 is mounted to a hybrid vehicle or an electrical vehicle to convert an electrical current, supplied from an electrical motor for a vehicle traveling, from the direct current to alternate current. In the vehicle air conditioner 1 of the eleventh embodiment, a coolant circuit is provided such that the coolant is circulated between the second heater core 14 and the inverter 111. Thus, the coolant after cooling the inverter 111 flows into the second heater core 15. On the other hand, the first heater core 14 is provided in the engine coolant circuit so that the coolant of the engine EG flows into the first heater core 14. Thus, the coolants having different temperatures flows into both the first heater core 14 and the second heater core 15. In the above-described eleventh embodiment, the other parts are similar to those of the above-described first embodiment.

Twelfth Embodiment

A twelfth embodiment of the present invention will be described with reference to FIG. 19. FIG. 19 is a schematic diagram showing an air conditioner 1 for a vehicle according to the twelfth embodiment of the present invention. In the above-described embodiments, the heat radiation portion, the heat absorption portion and the Peltier element are formed integrally with the heater core; however, the heat radiation portion, the heat absorption portion and the Peltier element may be formed separately from the heater core.

As shown in FIG. 19, a Peltier module 50, a heat radiation portion 34a and a heat absorption portion 34b are arranged in the first air passage 16 of the casing 111, and are fixed to the casing 11 separately from the second heater core 15.

The heat radiation portion 34a and the heat absorption portion 34b are made of metal such as Cu or Al, and are formed to form a coolant passage therein. Furthermore, the Peltier module 50 is arranged between the heat radiation portion 34a and the heat absorption portion 34b. The heat radiation portion 34a and the heat absorption portion 34b may be configured by a metal member and insulation layers of the Peltier module 50, similarly to the above first embodiment.

Thus, according to the present embodiment, because the heat radiation portion 34a is arranged in the first air passage 16, the heat amount discharged from the Peltier element 51 can be effectively used for the heating of air to be blown into the vehicle compartment.

Furthermore, because the Peltier module 50 is assembled into the casing 11, the Peltier module 50 can be mounted to the vehicle by mounting the casing 11 to the vehicle. In this case, it is unnecessary for the Peltier module 50 to be mounted in an engine compartment, thereby improving mounting performance.

Even in the twelfth embodiment, the heat absorption portion 34b may be arranged to contact the wall surface of the casing 11 inside of the casing 11 or outside of the first air passage 16 of the casing 11.

Other Embodiment

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.

(1) For example, in the above-described first embodiment, the inlet side portion 151a as the heat radiation portion and the outlet side portion 151b as the heat absorption portion are configured by the metal members and the insulation layers 56, 57 of the Peltier module 50, and thereby heat can be directly transmitted between the insulation layers 56, 57 and the coolant in the tube.

However, the inlet side portion 151a as the heat radiation portion and the outlet side portion 151b as the heat absorption portion may be configured by only the metal member of the tube 150. In this case, the insulation layers 56, 57 of the Peltier module 50 are arranged to directly contact the metal member of the inlet side portion 151a and the outlet side portion 151b, and thereby heat can be transmitted between the insulation layers 56, 57 and the coolant via the metal member of the inlet side portion 151a and the outlet side portion 151b.

(2) In the present embodiment, the inlet side portion 151a of the tube 151 is used as a part of a heat-exchanging portion in which the coolant is heat-exchanged with air. However, the inlet side portion 151a of the tube 151 may be configured such that the coolant before being heat-exchanged with air flows through the inlet side portion 151a without being heat-exchanged with air. Even in this case, the inlet side portion of the tube 151 used as the heat radiation portion can be formed integrally in the heater core 15.

(3) In the above-described embodiments, the number of the Peltier element(s) in the Peltier module 50 may be suitably set, and the number of the Peltier module(s) 50 may be suitably set.

(4) In the above-described embodiments provided with the first and second heater cores 14, 15, the Peltier module 50 is provided only in the second heater core 15; however, the Peltier module 50 may be arranged in both the first and second heater cores 14, 15. In this case, the structure of the first heater core 14 can be made similar to the structure of the second heater core 15.

(5) In the above-described first to ninth embodiments, the air conditioner according to the invention may used for a hybrid car having an engine EG and an electrical motor for a vehicle traveling. Alternatively, the air conditioner according to the invention may be suitably used for an idling-stop vehicle or other kinds of vehicles such as a fuel cell vehicle or an electrical vehicle that has a vehicle driving source other than the engine EG. Furthermore, in a case where the heat efficiency of the engine is improved and heat generation amount from the engine is small, the heat source from the engine is insufficient to perform the heating. In this case, the Peltier element 51 may be set to be always tuned ON.

In the above-described first embodiment, the coolant of the engine EG is used as the heating fluid flowing through the heater core(s). Furthermore, in the eleventh embodiment, the coolant of the inverter 111 is used as the heating fluid for heating air. However. Other heating fluids may be used for the heating of air to be blown into the vehicle compartment.

For example, a motor generator mounted to a hybrid vehicle or an electrical vehicle, or a fuel cell of a hybrid vehicle provided with an engine EG and the fuel cell may be used as a heat generator. In this case, heat exhausted from the heat generator mounted to the vehicle may be used in the vehicle. Furthermore, as the coolant used as the heating fluid, water is generally used. However, a cooling liquid for cooling a heat generator other than water may be used, or a cooling gas for cooling a heat generator may be used, as the heating fluid.

(6) The above described embodiments may be suitably combined if there is no contradiction therebetween.

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

Claims

1. An air conditioner for a vehicle, comprising:

a casing defining an air passage through which air flows into a vehicle compartment;

a heating heat exchanger disposed in the air passage of the casing to heat air to be blown toward the vehicle compartment by performing heat exchange between air and a heating fluid;

a heat radiation portion disposed to radiate heat to the heating fluid before being heat-exchanged in the heating heat exchanger;

a heat absorption portion disposed to absorb heat from the heating fluid after being heat-exchanged in the heating heat exchanger; and

a Peltier element disposed between the heat radiation portion and the heat absorption portion to pump heat from the heat absorption portion to the heat radiation portion, wherein the heat radiation portion is disposed in the air passage of the casing, in which the heating heat exchanger is disposed.

2. The air conditioner for a vehicle according to claim 1, wherein the heat radiation portion, the Peltier element and the heat absorption portion are formed integrally with the heating heat exchanger.

3. The air conditioner for a vehicle according to claim 1, wherein

the heating heat exchanger includes a passage forming member defining a heating fluid passage in which the heating fluid flows,

the heat radiation portion is configured by a heating-fluid inlet side portion of the passage forming member,

the heat absorption portion is configured by a heating-fluid outlet side portion of the passage forming member, and

the Peltier element is arranged between the heating-fluid inlet side portion and the heating-fluid outlet side portion of the passage forming member.

4. The air conditioner for a vehicle according to claim 3, wherein

the heat radiation portion configured by the heating-fluid inlet side portion of the passage forming member is a part of a heat-exchanging portion in which the heating fluid is heat-exchanged with air.

5. The air conditioner for a vehicle according to claim 3, wherein the passage forming member is formed in a serpentine shape.

6. The air conditioner for a vehicle according to claim 3, wherein

the heating heat exchanger includes a fin member that is arranged on an outer surface of the passage forming member in the heat exchanging portion to facilitate heat exchange between air and the heating fluid,

the fin member is arranged with different fin pitches at a heating-fluid upstream side of the passage forming member and at a heating-fluid downstream side of the passage forming member, and

the fin pitch of the fin member at the heating-fluid upstream side of the passage forming member is larger than the fin pitch of the fin member at the heating-fluid downstream side of the passage forming member.

7. The air conditioner for a vehicle according to claim 3, wherein

the heating-fluid inlet side portion used as the heat radiation portion and the heating-fluid outlet side portion used as the heat absorption portion have therein a passage height that is smaller than 1 mm.

8. The air conditioner for a vehicle according to claim 1, wherein

the heating heat exchanger includes a first heating heat exchanger, and a second heating heat exchanger disposed to heat air after passing through the first heating heat exchanger, and

the heat radiation portion, the Peltier element and the heat absorption portion are provided at least at the second heating heat exchanger, in the first and second heating heat exchangers.

9. The air conditioner for a vehicle according to claim 8, wherein

the heat radiation portion and the heat absorption portion are configured such that the heating fluid flowing out of the first heating heat exchanger is joined to the heating fluid flowing in the heat absorption portion or the heating fluid before flowing into the heat absorption portion.