Vehicle thermal management system

A heat medium discharge side of a first pump and a heat medium discharge side of a second pump are connected to a first switching valve in parallel with each other. Respective heat medium inlet sides of a plurality of temperature adjustment devices are connected to the first switching valve in parallel with each other. Respective heat medium outlet sides of the temperature adjustment devices are connected to a second switching valve in parallel with each other. A heat medium suction side of the first pump and a heat medium suction side of the second pump are connected to the second switching valve in parallel with each other. Each of the temperature adjustment devices is switched between a state in which the heat medium circulates between the device and the first pump, and another state in which the heat medium circulates between the device and the second pump.

CROSS REFERENCE TO RELATED APPLICATION APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C. 371 of International Application No. PCT/JP2013/000504 filed on Jan. 30, 2013 and published in Japanese as WO 2013/114874 A1 on Aug. 8, 2013. This application is based on Japanese Patent Applications No. 2012-020905 filed on Feb. 2, 2012, No. 2012-084444 filed on Apr. 3, 2012, and No. 2012-278552 filed on Dec. 20, 2012. The entire disclosures of all of the above applications are incorporated herein by reference.

FIELD OF THE INVENTION

The present disclosure relates to a thermal management system used for a vehicle.

BACKGROUND OF THE INVENTION

Conventionally, as disclosed in Patent Document 1, there is proposed a heat controller for cooling a motor generator, an inverter, a battery, and a vehicle compartment of an electric vehicle.

The heat controller in the related art includes a cooling circuit for allowing a coolant for cooling the motor generator and the inverter to circulate therethrough, a first circulation circuit for allowing a coolant for cooling the battery and vehicle compartment to circulate therethrough, and a second circulation circuit for allowing a coolant exchanging heat with outside air through an outdoor heat exchanger to circulate therethrough.

Further, the heat controller includes a first valve for connecting/disconnecting between the cooling circuit and the first circulation circuit, a second valve for connecting the cooling circuit to either the first circulation circuit or second circulation circuit, and a third valve for connecting/disconnecting between the cooling circuit and the second circulation circuit. The respective valves are controlled to switch the subject of connection of the cooling circuit between the first and second circulation circuits.

Heat can be transferred by a heat transfer device between the coolant circulating through the first circulation circuit and the coolant circulating through the second circulation circuit. The heat transfer device transfers the heat from the coolant at a high temperature to the coolant at a low temperature between the coolants in the first and second circulation circuits.

The heat of the coolant in the first circulation circuit is transferred to the coolant in the second circulation circuit by the heat transfer device, and the heat of the coolant in the second circulation circuit can be dissipated into the outside air by the outdoor heat exchanger, thereby cooling the battery and vehicle compartment.

The cooling circuit is connected to the first circulation circuit or second circulation circuit by use of the first to third valves, so that the heat of the coolant in the cooling circuit can be dissipated into the outside air by the outdoor heat exchanger in the second circulation circuit, thereby cooling the motor generator and inverter.

PRIOR ART DOCUMENT

Patent Document

Patent document 1: JP 2011-121551 A

SUMMARY OF INVENTION

The related art described above has an advantage that only one outdoor heat exchanger is required to cool a plurality of temperature adjustment devices, including the motor generator, the inverter, the battery, and the vehicle compartment in a cooling system. However, the entire circuit configuration might become complicated. In this case, as the number of temperature adjustment devices is increased, the circuit configuration becomes more complicated.

For example, the temperature adjustment devices which require cooling include an EGR cooler, an intake air cooler, and the like, in addition to the motor generator, the inverter, and the battery. Those devices have different required cooling temperatures.

In order to appropriately cool the respective temperature adjustment devices, the coolant to circulate through the respective devices is proposed to be switchable among the devices, which leads to an increase in the number of circulation circuits according to the number of devices for the temperature adjustment. Together with the increase, the number of valves for connecting/disconnecting between the respective circulation circuits and the cooling circuit is also increased, which results in a complicated structure of flow paths for connecting the respective circulation circuits and the cooling circuit.

The present disclosure has been made in view of foregoing points, and it is an object of the present disclosure to simplify the structure of a vehicle thermal management system that can switch heat media circulating through a plurality of temperature adjustment devices.

To achieve the above object, a vehicle thermal management system according to an aspect of the present disclosure includes: a first pump and a second pump drawing and discharging a heat medium; a heat medium heat exchanger that exchanges heat between the heat medium and outside air; a plurality of temperature adjustment devices with temperatures adjusted by the heat medium, each of the temperature adjustment devices having a flow path that allows the heat medium to flow therethrough; a first switching valve that switches an inflow state of the heat medium flowing into each of the temperature adjustment devices between one state in which the heat medium discharged from the first pump flows to the temperature adjustment devices, and another state in which the heat medium discharged from the second pump flows to the temperature adjustment devices, wherein a heat medium discharge side of the first pump and a heat medium discharge side of the second pump are connected in parallel with each other, and respective heat medium inlet sides of the temperature adjustment devices are connected in parallel with each other; a second switching valve that switches an outflow state of the heat medium from each of the temperature adjustment devices between one state in which the heat medium flowing out of the temperature adjustment devices flows to the first pump, and another state in which the heat medium flowing out of the temperature adjustment devices flows to the second pump, wherein a heat medium suction side of the first pump and a heat medium suction side of the second pump are connected in parallel with each other, and respective heat medium outlet sides of the temperature adjustment devices are connected in parallel with each other; and a controller that controls operations of the first switching valve and the second switching valve to switch between (i) one circulation state of the heat medium circulating between the first pump and the temperature adjustment devices, and (ii) another circulation state of the heat medium circulating between the second pump and the temperature adjustment devices.

Accordingly, the temperature adjustment devices are connected in parallel between the first and second switching valves for switching the flows of heat media. With such a simple structure, the heat media circulating through the temperature adjustment devices can be switched among the devices of interest.

EMBODIMENTS FOR CARRYING OUT INVENTION

First Embodiment

In the following, a first embodiment of the invention will be described based onFIGS. 1 to 15. A vehicle thermal management system10shown inFIG. 1is used to cool various devices mounted on a vehicle (devices requiring cooling or heating) or an interior of the vehicle to an appropriate temperature.

In this embodiment, the cooling system10is applied to a hybrid car that can obtain the driving force for traveling from both an internal combustion engine (engine) and an electric motor for traveling.

A hybrid car of this embodiment is configured as a plug-in hybrid car that can charge a battery (vehicle-mounted battery) mounted on the vehicle, with power supplied from an external power source (commercial power source) during stopping of the vehicle. For example, a lithium ion battery can be used as the battery.

A driving force output from the engine is used not only for traveling of the vehicle, but also for operating a generator. Power generated by the generator and power supplied from the external power source can be stored in the battery. The power stored in the battery can be supplied not only to the electric motor for traveling, but also to various vehicle-mounted devices, such as electric components included in the cooling system.

As shown inFIG. 1, the cooling system10includes a first pump11, a second pump12, a radiator13, a coolant cooler14, a battery cooler15, an inverter cooler16, an exhaust gas cooler17, a cooler core18, a first switching valve19, and a second switching valve20.

The first ump11and the second pump12are an electric pump for drawing and discharging the coolant (heat medium). The coolant is preferably liquid containing at least ethylene glycol or dimethylpolysiloxane.

The radiator13is a heat exchanger for heat dissipation (radiator) that dissipates heat of the coolant into the outside air by exchanging heat between the coolant and the outside air. The coolant outlet side of the radiator13is connected to the coolant suction side of the first pump11. An outdoor blower21is an electric blower for blowing the outside air to the radiator13. The radiator13and the outdoor blower21are disposed at the forefront of the vehicle. Thus, during traveling of the vehicle, the radiator13can face the traveling air.

The coolant cooler14is a cooling device for cooling the coolant by exchanging heat between the coolant and a low-pressure refrigerant of a refrigeration cycle22. The coolant inlet side of the coolant cooler14is connected to the coolant discharge side of the second pump12.

The coolant cooler14serves as an evaporator of the refrigeration cycle22. The refrigeration cycle22is an evaporation compression refrigerator which includes a compressor23, a condenser24, an expansion valve25, and the coolant cooler14as the evaporator. The refrigeration cycle22of this embodiment employs a fluorocarbon refrigerant as the refrigerant, and forms a subcritical refrigeration cycle whose high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant.

The compressor23is an electric compressor driven by power supplied from the battery. The compressor23draws and compresses the refrigerant in the refrigeration cycle22to discharge the compressed refrigerant therefrom. The condenser24is a high-pressure side heat exchanger for condensing a high-pressure refrigerant by exchanging heat between the outside air and the high-pressure refrigerant discharged from the compressor23.

The expansion valve25is a decompression device for decompressing and expanding a liquid-phase refrigerant condensed by the condenser24. The coolant cooler14is a low-pressure side heat exchanger for evaporating a low-pressure refrigerant by exchanging heat between the coolant and the low-pressure refrigerant decompressed and expanded by the expansion valve25. The gas-phase refrigerant evaporated at the coolant cooler14is sucked into and compressed by the compressor23.

The radiator13serves to cool the coolant by the outside air, while the coolant cooler14serves to cool the coolant by the low-pressure refrigerant of the refrigeration cycle22. Thus, the temperature of the coolant cooled by the coolant cooler14is lower than that of the coolant cooled by the radiator13.

Specifically, the radiator13cannot cool the coolant to a temperature lower than that of the outside air, whereas the coolant cooler14can cool the coolant to a temperature lower than that of the outside air.

Hereinafter, the coolant cooled by the outside air in the radiator13is referred to as an “intermediate-temperature coolant”, and the coolant cooled by the low-pressure refrigeration of the refrigerant cycle22in the coolant cooler14is referred to as a “low-temperature coolant”.

Each of the coolant cooler14, the battery cooler15, the inverter cooler16, the exhaust gas cooler17, and the cooler core18is the device whose temperature is adjusted by either the intermediate-temperature coolant or the low-temperature coolant.

The battery cooler15has a flow passage for coolant, and cools the battery by dissipating the heat of the battery into the coolant.

The battery preferably has its temperature maintained in a range of about 10 to 40° C. for the purpose of preventing the reduction in output, charging efficiency, degradation, and the like.

The inverter cooler16has a flow passage for coolant, and cools the inverter by dissipating the heat of the inverter into the coolant.

The inverter is a power converter that converts a direct-current (DC) power supplied from the battery to an alternating-current (AC) voltage to output the AC voltage to an electric motor for traveling. The inverter preferably has its temperature maintained at 65° C. or lower for the purpose of preventing the degradation thereof or the like.

The exhaust gas cooler17has a flow passage for coolant, and cools exhaust gas by dissipating the heat of the exhaust gas of the engine into the coolant. The exhaust gas cooled by the exhaust gas cooler17is returned to the intake side of the engine. The exhaust gas returned to the intake side of the engine has its temperature maintained in a range of 40 to 100° C. for the purpose of reducing the engine loss, and preventing knocking and generation of NOX, and the like.

The cooler core18is a heat exchanger for cooling (air cooler) that cools blast air by exchanging heat between the coolant and the blast air. An indoor blower26is an electric blower for blowing the outside air to the cooler core18. The cooler core18and the indoor blower26are disposed inside a casing27of the indoor air conditioning unit.

Each of the first and second switching valves19and20is a flow switching device that switches the flow of coolant. The first switching valve19and second switching valve20have the same basic structure. However, the first switching valve19differs from the second switching valve20in that an inlet and outlet for the coolant are reversed to each other.

The first switching valve19includes two inlets19aand19bas an inlet for the coolant, and four outlets19c,19d,19e, and19fas an outlet for the coolant.

The inlet19ais connected to the coolant discharge side of the first pump11. The inlet19bis connected to the coolant outlet side of the coolant cooler14.

The outlet19cis connected to the coolant inlet side of the cooler core18. The outlet19dis connected to the coolant inlet side of the exhaust gas cooler17. The outlet19eis connected to the coolant inlet side of the battery cooler15. The outlet19fis connected to the coolant inlet side of the inverter cooler16.

The second switching valve20includes inlets20a,20b,20c, and20das an inlet for the coolant, and outlets20e, and20fas an outlet for the coolant.

The inlet20ais connected to the coolant outlet side of the cooler core18. The inlet20bis connected to the coolant outlet side of the exhaust gas cooler17. The inlet20cis connected to the coolant outlet side of the battery cooler15. The inlet20dis connected to the coolant outlet side of the inverter cooler16.

The outlet20eis connected to the coolant inlet side of the radiator13. The outlet20fis connected to the coolant suction side of the second pump12.

The first switching valve19is configured to be capable of switching among three types of communication states between the inlets19aand19band the outlets19c,19d,19e, and19f. The second switching valve20is also configured to be capable of switching among three types of communication states between the inlets20a,20b,20c, and20dand the outlets20e, and20f.

FIG. 2shows the operation (first mode) of the cooling system10when the first and second switching valves19and20are switched to a first state.

In the first state, the first switching valve19connects the inlet19awith the outlets19d,19e, and19f, and also connects the inlet19bwith the outlet19c. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19d,19e, and19fas indicated by alternate long and short dash lines with arrows inFIG. 2, and also allows the coolant entering the inlet19bto flow out of the outlet19cas indicated by a solid arrow inFIG. 2.

In the first state, the second switching valve20connects the inlets20b,20c, and20dwith the outlet20e, and also connects the inlet20awith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlets20b,20c, and20dto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIG. 2, and also allows the coolant entering the inlet20ato flow out of the outlet20fas a solid arrow inFIG. 2.

FIG. 3shows the operation (second mode) of the cooling system10when the first and second switching valves19and20are switched to a second state.

In the second state, the first switching valve19connects the inlet19awith the outlets19d, and19f, and also connects the inlet19bwith the outlets19cand19e. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19dand19fas indicated by alternate long and short dash lines with arrows inFIG. 3, and also allows the coolant entering the inlet19bto flow out of the outlets19cand19eas indicated by solid arrows inFIG. 3.

In the second state, the second switching valve20connects the inlets20aand20cwith the outlet20f, and also connects the inlet20band20dwith the outlet20e. Thus, the second switching valve20allows the coolant entering the inlets20band20dto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIG. 3, and also allows the coolant entering the inlets20aand20cto flow out of the outlet20fas indicated by solid lines with an arrow inFIG. 3.

FIG. 4shows the operation (third mode) of the cooling system10when the first and second switching valves19and20are switched to a third state.

In the third state, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19c,19e, and19f. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 4, and also allows the coolant entering the inlet19bto flow out of the outlets19c,19e, and19fas indicated by solid arrows inFIG. 4.

In the third state, the second switching valve20connects the inlet20bwith the outlet20eand also connects the inlets20a,20c, and20dwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlet20bto flow out of the outlet20eas indicated by an alternate long and short dash line with an arrow inFIG. 4, and also allows the coolant entering the inlets20a,20c, and20dto flow out of the outlet20fas indicated by a solid arrow inFIG. 4.

As shown inFIG. 5, the first switching valve19and the second switching valve20include rotary shafts191and201of valve elements, respectively. A rotative force of an output shaft30aof an electric motor30for a switching valve is transmitted to the rotary shafts191and201via gears31,32,33, and34. Thus, by the common electric motor30for a switching valve, the valve elements of the first and second switching valves19and20are driven to cooperatively rotate.

Alternatively, an electric motor for a switching valve may be individually provided in each of the first and the second switching valves19and20. In such a case, the operations of the two electric motors for the switching valves may be cooperatively controlled, whereby the valve elements of the first and second switching valves19and20are driven to cooperatively rotate.

The first switching valve19and the second switching valve20have the same basic structure. In the following, the specific structure of the first switching valve19will be described, and thus the description of the specific structure of the second switching valve20will be omitted.

The first switching valve19includes a case192serving as an outer shell. The case192is formed in a substantially cylindrical shape extending in the longitudinal direction of the rotary shaft191of the valve element (in the vertical direction ofFIG. 5). The rotary shaft191of the valve element penetrates one end surface (upper end surface shown inFIG. 5) of the case192.

The cylindrical surface of the case192has outer and inner diameters thereof decreased in four stages from one end side (upper end side ofFIG. 5) to the other end side (lower end side ofFIG. 5). Specifically, at the cylindrical surface of the case192, a first cylindrical portion192awith the largest outer and inner diameters, a second cylindrical portion192bwith the second largest outer and inner diameters, a third cylindrical portion192cwith the third largest outer and inner diameters, and a fourth cylindrical portion192dwith the smallest outer and inner diameters are formed in that order from the one end side to the other end side.

The first cylindrical portion192ais provided with the outlet19c. The second cylindrical portion192bis provided with the outlet19d. The third cylindrical portion192cis provided with the outlet19e. The fourth cylindrical portion192dis provided with the outlet19f.

As shown inFIG. 6, at the other end surface of the case192(lower end surface shown inFIG. 6), the inlet19afor coolant and the inlet19bfor coolant are formed.

An inner cylindrical member193is inserted into an internal space of the case192. The inner cylindrical member193is formed in a cylindrical shape with constant inner and outer diameters, and positioned coaxially with respect to the case192. One end of the inner cylindrical member193on the other end side of the case192(the lower end thereof shown inFIG. 6) is fixed in close contact with the other end surface of the case192.

A partition plate193ais provided within the inner cylindrical member193. The partition plate193ais formed across the entire area of the inner cylindrical member193in the axial direction thereof to partition the internal space of the inner cylindrical member193into two half-round spaces193band193c.

The first space193bof the two spaces193band193ccommunicates with the inlet19aof the case192, and the second space193cthereof communicates with the inlet19bof the case192.

The cylindrical surface of the inner member193is provided with four openings193d,193e,193f, and193gcommunicating with the first space193b, and four openings193h,193i,193j, and193kcommunicating with the second space193c.

With the inner cylindrical portion193inserted into the case192, the openings193dand193hof the inner cylindrical member193are opposed to the first cylindrical portion192aof the cylindrical member193, the openings193eand193iare opposed to the second cylindrical portion192bof the inner cylindrical member193, the openings193fand193jare opposed to the third cylindrical portion192cof the inner cylindrical member193, and the openings193gand193kare opposed to the fourth cylindrical portion192dof the inner cylindrical member193.

A valve element194for opening and closing eight openings193dto193kof the inner cylindrical member193is inserted into between the case192and the inner cylindrical member193. The valve element194is formed in a substantially cylindrical shape, and positioned coaxially with respect to the case192and the inner cylindrical member193.

A rotary shaft191is fixed to the center of one end surface (upper end surface ofFIG. 6) of the valve element194. The valve element194is rotatable with the rotary shaft191centered with respect to the case192and the inner cylindrical member193.

The inner diameter of the valve element194is set constant, like the outer diameter of the inner cylindrical member193. Like the inner diameter of the case192, the outer diameter of the valve element194is decreased in four stages from one end side to the other end side thereof.

Specifically, at the outer peripheral surface of the valve element194, a first cylindrical portion194awith the largest outer diameter, a second cylindrical portion194bwith the second largest outer diameter, a third cylindrical portion194cwith the third largest outer diameter, and a fourth cylindrical portion194dwith the smallest outer diameter are formed in that order from the one end side to the other end side.

With the valve element194inserted into between the case192and the inner cylindrical member193, the first cylindrical portion194aof the valve element194is opposed to the first cylindrical portion192aof the case192, the second cylindrical portion194bof the valve element194is opposed to the second cylindrical portion192bof the case192, the third cylindrical portion194cof the valve element194is opposed to the third cylindrical portion194cof the case192, and the fourth cylindrical portion194dof the valve element194is opposed to the fourth cylindrical portion194dof the case192.

A plurality of holes194eis formed at the first cylindrical portion194aof the valve element194. A plurality of holes194fis formed at the second cylindrical portion194bof the valve element194. A plurality of holes194gis formed at the third cylindrical portion194cof the valve element194. A plurality of holes194his formed at the fourth cylindrical portion194dof the valve element194.

FIG. 7is a cross-sectional view of the first switching valve19taken at a part of the first cylindrical portion194aof the valve element194in the direction perpendicular to the axial direction thereof.

The three holes194eof the first cylindrical portion194aof the valve element194are formed in the circumferential direction of the first cylindrical portion194a. When the valve element194is located in a predetermined rotating position, the holes194eare superimposed over the openings193dand193hof the inner cylindrical member193.

A packing195is fixed to the periphery of each of the openings193dand193hof the inner cylindrical member193. The packing195is in close contact with the first cylindrical portion194aof the valve element194, and serves to seal a gap between the first cylindrical portion194aand the openings193dand193hof the inner cylindrical member193in a liquid-tight manner.

A first ring-like space196ais formed between the first cylindrical portion194aof the valve element194and the first cylindrical portion192aof the case192. The first ring-like space196acommunicates with the outlet19c.

FIG. 8is a cross-sectional view of the first switching valve19taken at a part of the second cylindrical portion194bof the valve element194in the direction perpendicular to the axial direction thereof.

The three holes194fof the second cylindrical portion194bof the valve element194are formed in the circumferential direction of the second cylindrical portion194b. When the valve element194is located in a predetermined rotating position, the holes194fare superimposed over the openings193eand193iof the inner cylindrical member193.

The packing195is fixed to the periphery of each of the openings193eand193iof the inner cylindrical member193. The packing195is in close contact with the second cylindrical portion194bof the valve element194, and serves to seal a gap between the second cylindrical portion194band the openings193eand193iof the inner cylindrical member193in a liquid-tight manner.

A second ring-like space196bis formed between the second cylindrical portion194bof the valve element194and the second cylindrical portion192bof the case192. The second ring-like space196bcommunicates with the outlet19d.

FIG. 9is a cross-sectional view of the first switching valve19taken at a part of the third cylindrical portion194cof the valve element194in the direction perpendicular to the axial direction thereof.

The three holes194gof the third cylindrical portion194cof the valve element194are formed in the circumferential direction of the third cylindrical portion194c. When the valve element194is located in a predetermined rotating position, the holes194gare superimposed over the openings193fand193jof the inner cylindrical member193.

The packing195is fixed to the periphery of each of the openings193fand193jof the inner cylindrical member193. The packing195is in close contact with the third cylindrical portion194cof the valve element194, and serves to seal a gap between the third cylindrical portion194cand the openings193fand193jof the inner cylindrical member193in a liquid-tight manner.

A third ring-like space196cis formed between the third cylindrical portion194cof the valve element194and the third cylindrical portion192cof the case192. The third ring-like space196ccommunicates with the outlet19e.

FIG. 10is a cross-sectional view of the first switching valve19taken at a part of the fourth cylindrical portion194dof the valve element194in the direction perpendicular to the axial direction thereof.

The three holes194hof the fourth cylindrical portion194dof the valve element194are formed in the circumferential direction of the third cylindrical portion194c. When the valve element194is located in a predetermined rotating position, the holes194hare superimposed over the openings193gand193kof the inner cylindrical member193.

The packing195is fixed to the periphery of each of the openings193gand193kof the inner cylindrical member193. The packing195is in close contact with the fourth cylindrical portion194dof the valve element194, and serves to seal a gap between the fourth cylindrical portion194dand the openings193gand193kof the inner cylindrical member193in a liquid-tight manner.

A fourth ring-like space196dis formed between the fourth cylindrical portion194dof the valve element194and the fourth cylindrical portion192dof the case192. The fourth ring-like space196dcommunicates with the outlet19f.

As shown inFIG. 11, a gap between the first ring-like space196aand the second ring-like space196bis sealed by a packing197in a liquid-tight manner. The packing197is formed in a ring-like shape so as to have its entire periphery sandwiched between a stepped surface of the valve element194and a stepped surface of the case192.

Although not shown, a gap between the second and third ring-like spaces196band196c, as well as a gap between the third and fourth ring-like spaces196cand196dare also sealed by the ring-like packing197in the liquid-tight manner.

The first state of the first switching valve19will be described below based onFIG. 12.FIG. 12is a cross-sectional view of the first switching valve19taken at a part of the first cylindrical portion194aof the valve element194in the direction perpendicular to the axial direction thereof. For better understanding of the description,FIG. 12illustrates only one of three holes of each of the types194e,194f,194g, and194hwhile omitting the illustration of other remaining two holes194e,194f,194g, and194hof each type.

In the first state, the valve element194is rotated to the position shown inFIG. 12, so that the hole194eof the first cylindrical portion194aof the valve element194is superimposed over the opening193hon the second space193cside of the inner cylindrical member193, thereby causing the first cylindrical portion194aof the valve element194to close the opening193don the first space193bside of the inner cylindrical member193.

Thus, as indicated by the solid arrows inFIG. 12, the second space193cof the inner cylindrical member193communicates with the outlet19cvia the opening193hof the inner cylindrical member193, the hole194eof the valve element194, and the first ring-like space196a. On the other hand, the first space193bof the inner cylindrical member193does not communicate with the outlet19c.

Accordingly, in the first state, the outlet19ccommunicates with the inlet19b, and not with the inlet19a.

Although not shown, in the first state, the hole194fof the second cylindrical portion194bof the valve element194is superimposed over the opening193eon the first space193bside of the inner cylindrical member193, thereby causing the second cylindrical portion194bof the valve element194to close the opening193ion the second space193cside of the inner cylindrical member193.

Thus, as indicated by the dashed arrows inFIG. 12, the first space193bof the inner cylindrical member193communicates with the outlet19d, and the second space193cof the inner cylindrical member193does not communicate with the outlet19d. Accordingly, the outlet19dcommunicates with the inlet19a, and not with the inlet19b.

Although not shown, in the first state, the hole194gof the third cylindrical portion194cof the valve element194is superimposed over the opening193fon the first space193bside of the inner cylindrical member193, thereby causing the third cylindrical portion194cof the valve element194to close the opening193jon the second space193cside of the inner cylindrical member193.

Thus, as indicated by a broken line with an arrow inFIG. 12, the first space193bof the inner cylindrical member193communicates with the outlet19e, and the second space193cof the inner cylindrical member193does not communicate with the outlet19e. Accordingly, the outlet19ecommunicates with the inlet19a, and not with the inlet19b.

Although not shown, in the first state, the hole194hof the fourth cylindrical portion194dof the valve element194is superimposed over the opening193gon the first space193bside of the inner cylindrical member193, thereby causing the fourth cylindrical portion194dof the valve element194to close the opening193kon the second space193cside of the inner cylindrical member193.

Thus, as indicated by a broken line with an arrow inFIG. 12, the first space193bof the inner cylindrical member193communicates with the outlet19f, and the second space193cof the inner cylindrical member193does not communicate with the outlet19f. Accordingly, the outlet19fcommunicates with the inlet19a, and not with the inlet19b.

The second state of the first switching valve19will be described below based onFIG. 13.FIG. 13is a cross-sectional view of the first switching valve19taken at a part of the first cylindrical portion194aof the valve element194in the direction perpendicular to the axial direction thereof. For better understanding of the description,FIG. 13illustrates only one of three holes of each of the types194e,194f,194g, and194hwhile omitting the illustration of other remaining two holes194e,194f,194g, and194hof each type.

In the second state, the valve element194is rotated to the position shown inFIG. 13, so that the hole194eof the first cylindrical portion194aof the valve element194is superimposed over the opening193hon the second space193cside of the inner cylindrical member193, thereby causing the first cylindrical portion194aof the valve element194to close the opening193don the first space193bside of the inner cylindrical member193.

Thus, as indicated by a solid arrow inFIG. 13, the second space193cof the inner cylindrical member193communicates with the outlet19c, and the first space193bof the inner cylindrical member193does not communicate with the outlet19c. Accordingly, the outlet19ccommunicates with the inlet19b, and not with the inlet19a.

Although not shown, in the second state, the hole194fof the second cylindrical portion194bof the valve element194is superimposed over the opening193eon the first space193bside of the inner cylindrical member193, thereby causing the second cylindrical portion194bof the valve element194to close the opening193ion the second space193cside of the inner cylindrical member193.

Thus, as indicated by a broken line with an arrow inFIG. 13, the first space193bof the inner cylindrical member193communicates with the outlet19d, and the second space193cof the inner cylindrical member193does not communicate with the outlet19d. Accordingly, the outlet19dcommunicates with the inlet19a, and not with the inlet19b.

Although not shown, in the second state, the hole194gof the third cylindrical portion194cof the valve element194is superimposed over the opening193jon the second space193cside of the inner cylindrical member193, thereby causing the third cylindrical portion194cof the valve element194to close the opening193fon the first space193bside of the inner cylindrical member193.

Thus, as indicated by a broken line with an arrow inFIG. 13, the second space193cof the inner cylindrical member193communicates with the outlet19e, and the first space193bof the inner cylindrical member193does not communicate with the outlet19e. Accordingly, the outlet19ecommunicates with the inlet19b, and not with the inlet19a.

Although not shown, in the second state, the hole194hof the fourth cylindrical portion194dof the valve element194is superimposed over the opening193gon the first space193bside of the inner cylindrical member193, thereby causing the fourth cylindrical portion194dof the valve element194to close the opening193kon the second space193cside of the inner cylindrical member193.

Thus, as indicated by another broken line with an arrow inFIG. 13, the first space193bof the inner cylindrical member193communicates with the outlet19f, and the second space193cof the inner cylindrical member193does not communicate with the outlet19f. Accordingly, the outlet19fcommunicates with the inlet19a, and not with the inlet19b.

The third state of the first switching valve19will be described below based onFIG. 14.FIG. 14is a cross-sectional view of the first switching valve19taken at a part of the first cylindrical portion194aof the valve element194in the direction perpendicular to the axial direction thereof. For better understanding of the description,FIG. 14illustrates only one of three holes of each of the types194e,194f,194g, and194hwhile omitting the illustration of other remaining two holes194e,194f,194g, and194hof each type.

In the third state, the valve element194is rotated to the position shown inFIG. 14, so that the hole194eof the first cylindrical portion194aof the valve element194is superimposed over the opening193hon the second space193cside of the inner cylindrical member193, thereby causing the first cylindrical portion194aof the valve element194to close the opening193don the first space193bside of the inner cylindrical member193.

Thus, as indicated by a solid arrow inFIG. 14, the second space193cof the inner cylindrical member193communicates with the outlet19c, and the first space193bof the inner cylindrical member193does not communicate with the outlet19c. Accordingly, the outlet19ccommunicates with the inlet19b, and not with the inlet19a.

Although not shown, in the third state, the hole194fof the second cylindrical portion194bof the valve element194is superimposed over the opening193eon the first space193bside of the inner cylindrical member193, thereby causing the second cylindrical portion194bof the valve element194to close the opening193ion the second space193cside of the inner cylindrical member193.

Thus, as indicated by a broken line with an arrow inFIG. 14, the first space193bof the inner cylindrical member193communicates with the outlet19d, and the second space193cof the inner cylindrical member193does not communicate with the outlet19d. Accordingly, the outlet19dcommunicates with the inlet19a, and not with the inlet19b.

Although not shown, in the third state, the hole194gof the third cylindrical portion194cof the valve element194is superimposed over the opening193jon the second space193cside of the inner cylindrical member193, thereby causing the third cylindrical portion194cof the valve element194to close the opening193fon the first space193bside of the inner cylindrical member193.

Thus, as indicated by a broken line with an arrow inFIG. 14, the second space193cof the inner cylindrical member193communicates with the outlet19e, and the first space193bof the inner cylindrical member193does not communicate with the outlet19e. Accordingly, the outlet19ecommunicates with the inlet19b, and not with the inlet19a.

Although not shown, in the third state, the hole194hof the fourth cylindrical portion194dof the valve element194is superimposed over the opening193kon the second space193cside of the inner cylindrical member193, thereby causing the fourth cylindrical portion194dof the valve element194to close the opening193gon the first space193bside of the inner cylindrical member193.

Thus, as indicated by a broken line with an arrow inFIG. 14, the second space193cof the inner cylindrical member193communicates with the outlet19f, and the first space193bof the inner cylindrical member193does not communicate with the outlet19f. Accordingly, the outlet19fcommunicates with the inlet19b, and not with the inlet19a.

Next, an electric controller of the cooling system10will be described with reference toFIG. 15. A controller40is comprised of a known microcomputer, including CPU, ROM, RAM, and the like, and a peripheral circuit thereof. The controller40is a control device for controlling the operations of the devices connected to the output side thereof, including the first pump11, the second pump12, the compressor23, the electric motor30for a switching valve, and the like by performing various kinds of computations and processing based on air conditioning control programs stored in the ROM.

The controller40is integrally structured with a control unit for controlling various devices for control connected to an output side thereof. The control unit for controlling the operations of the devices for control has a structure (hardware and software) that is adapted to control the operation of each of the devices for control.

In this embodiment, particularly, the structure (hardware and software) that controls the operation of the electric motor30for a switching valve acts as a switching valve controller40a. Obviously, the switching valve controller40amay be independently provided from the controller40.

Detection signals from a group of sensors, including an inside air sensor41, an outside air sensor42, a water temperature sensor43, and the like are input to the input side of the controller40.

The inside air sensor41is a detector (inside air temperature detector) for detecting the temperature of inside air (temperature of the vehicle interior). The outside air sensor42is a detector (outside air temperature detector) for detecting the temperature of outside air. The water temperature sensor43is a detector (heat medium temperature detector) for detecting the temperature of coolant flowing therethrough directly after passing through the radiator13.

An operation signal is input from an air conditioning switch44to the input side of the controller40. The air conditioning switch44is a switch for switching an air conditioner between ON and OFF (in other words, ON and OFF of cooling), and disposed near a dash board in the vehicle compartment.

Now, the operation of the above-mentioned structure will be described. When an outside air temperature detected by the outside air sensor42is equal to or lower than 15° C., the controller40performs the first mode shown inFIG. 2. When an outside air temperature detected by the outside air sensor42ranges from more than 15° C. and less than 40° C., the controller40performs the second mode shown inFIG. 3. When an outside air temperature detected by the outside air sensor42is equal to or higher than 40° C., the controller40performs the third mode shown inFIG. 4.

In the first mode, the controller40controls the electric motor30for a switching valve such that the first switching valve19and the second switching valve20are brought into the first state shown inFIG. 2to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlets19d,19e, and19f, and also connects the inlet19bwith the outlet19c. The second switching valve20connects the inlets20b,20c, and20dwith the outlet20e, and also connects the inlet20awith the outlet20f.

Accordingly, a first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the battery cooler15, the inverter cooler16, the exhaust gas cooler17, and the radiator13, whereas a second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, and the cooler core18.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 2, the coolant discharged from the first pump11is branched by the first switching valve19into the battery cooler15, the inverter cooler16, and the exhaust gas cooler17. Then, the coolant flows in parallel through the battery cooler15, the inverter cooler16, and the exhaust gas cooler17are collected into the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by a solid arrow inFIG. 2, the coolant discharged from the second pump12flows through the coolant cooler14and then through the cooler core18via the first switching valve19into the second switching valve20. The coolant flows through the second switching valve20, thereby being sucked into the second pump12.

Thus, in the first mode, the intermediate-temperature coolant cooled by the radiator13flows through the battery cooler15, the inverter cooler16, and the exhaust gas cooler17, whereas the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18.

As a result, the battery, the inverter, and the exhaust gas are cooled by the intermediate-temperature coolant, and the blast air into the vehicle interior is cooled by the low-temperature coolant.

For example, when the outside air temperature is about 15° C., the intermediate-temperature coolant cooled by the outside air in the radiator13becomes at a temperature of about 25° C., so that the intermediate-temperature coolant can sufficiently cool the battery, inverter, and exhaust gas.

The low-temperature coolant cooled by the low-pressure refrigerant of the refrigeration cycle22in the coolant cooler14is at about 0° C., so that the blast air into the vehicle interior can be sufficiently cooled by the low-temperature coolant.

In the first mode, the battery, inverter, and exhaust gas are cooled by the outside air, which can effectively achieve the energy saving as compared to the case in which the battery, inverter, and exhaust gas are cooled by the low-pressure refrigerant of the refrigeration cycle22.

In the second mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the second state shown inFIG. 3to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlets19dand19f, and also connects the inlet19bwith the outlets19cand19e. The second switching valve20connects the inlets20band20dwith the outlet20e, and also connects the inlets20aand20cwith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the inverter cooler16, the exhaust gas cooler17, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, and the battery cooler15.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 3, the coolant discharged from the first pump11is branched by the first switching valve19into the inverter cooler16and the exhaust gas cooler17. Then, the coolants flowing in parallel through the inverter cooler16and the exhaust gas cooler17are collected into the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 3, the coolant discharged from the second pump12flows through the coolant cooler14, and is branched by the first switching valve19into the cooler core18and the battery cooler15. Then, the coolants flowing in parallel through the cooler core18and the battery cooler15are collected into the second switching valve20to be sucked into the second pump12.

That is, in the second mode, the intermediate-temperature coolant cooled by the radiator13flows through the inverter cooler16and the exhaust gas cooler17, whereas the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18and the battery cooler15.

As a result, the inverter and the exhaust gas are cooled by the intermediate-temperature coolant, and the battery and the blast air into the vehicle interior are cooled by the low-temperature coolant.

For example, when the outside air temperature is about 25° C., the intermediate-temperature coolant cooled by the outside air in the radiator13becomes at a temperature of about 40° C., so that the intermediate-temperature coolant can sufficiently cool the inverter, and exhaust gas.

The low-temperature coolant cooled by the low-pressure refrigerant of the refrigeration cycle22in the coolant cooler14is at about 0° C., so that the battery and the blast air into the vehicle interior can be sufficiently cooled by the low-temperature coolant.

Since in the second mode the battery is cooled by the low-pressure refrigerant of the refrigeration cycle22, the battery can be sufficiently cooled even when the outside air cannot cool the battery adequately because of the high temperature of the outside air.

In the third mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the third state shown inFIG. 4to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlet19dand also connects the inlet19bwith the outlets19c,19e, and19f. The second switching valve20connects the inlet20bwith the outlet20e, and also connects the inlets20a,20c, and20dwith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the exhaust gas cooler17, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, the battery cooler15, and the inverter cooler16.

That is, as indicated by an alternate long and short dash line with an arrow inFIG. 4, the coolant discharged from the first pump11flows through the exhaust gas cooler17via the first switching valve19, and then through the radiator13via the second switching valve20, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 4, the coolant discharged from the second pump12flows through the coolant cooler14, and is branched by the first switching valve19into the cooler core18, the battery cooler15, and the inverter cooler16. Then, the coolants flowing in parallel through the cooler core18, the battery cooler15, and the inverter cooler16are collected into the second switching valve20to be sucked into the second pump12.

Thus, in the third mode, the intermediate-temperature coolant cooled by the radiator13flows through the exhaust gas cooler17, whereas the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18, the battery cooler15, and the inverter cooler16.

Thus, the exhaust gas is cooled by the coolant cooled by the radiator13, and the blast air into the vehicle interior, the battery, and the inverter are cooled by the coolant cooled by the coolant cooler14.

For example, when the outside air temperature is about 40° C., the intermediate-temperature coolant cooled by the outside air in the radiator13becomes at a temperature of about 50° C., so that the intermediate-temperature coolant can sufficiently cool the exhaust gas.

The low-temperature coolant cooled by the low-pressure refrigerant of the refrigeration cycle22in the coolant cooler14is at about 0° C., so that the blast air into the vehicle interior, the battery, and the inverter can be sufficiently cooled by the low-temperature coolant.

Since in the third mode the battery and the inverter are cooled by the low-pressure refrigerant of the refrigeration cycle22, the battery and the inverter can be sufficiently cooled even when the outside air cannot cool the battery and the inverter adequately because of the very high temperature of the outside air.

This embodiment employs the simple structure in which the temperature adjustment devices15,16,17, and18are connected in parallel between the first and second switching valves19and20, so that the coolants circulating through the respective temperature adjustment devices15,16,17, and18can be switched among the devices.

Specifically, the outside air temperature is detected as a temperature associated with the temperature of the coolant obtained after the heat exchange by the radiator13, and then based on the outside air temperature detected, the operations of the first switching valve19and the second switching valve20are controlled to thereby perform the first to third modes. Thus, the coolant circulating through each of the temperature adjustment devices15,16,17, and18can be switched among the devices according to the temperature of the coolant obtained after the heat exchange by the radiator13.

More specifically, when the outside air temperature is lower than a predetermined temperature (15° C. in this embodiment), the first mode is performed to allow the coolant to circulate between the first pump11and each of the temperature adjustment devices15,16,17, and18. When the outside air temperature is higher than the predetermined temperature (15° C. in this embodiment), the operation is shifted from the second mode to the third mode as the outside air temperature becomes higher, which increases the number of devices for temperature for allowing the coolant to circulate through the second pump12.

Thus, the cooling load of the coolant cooler14(that is, cooling load of the refrigeration cycle22) can be changed according to the temperature of the coolant obtained after the heat exchange by the radiator13, which can achieve the energy saving.

More specifically, the temperature adjustment devices15,16,17, and18have different required cooling temperatures. When the outside air temperature is higher than the predetermined temperature (15° C. in this embodiment), as the outside air temperature becomes higher, the operation is shifted from the second mode to the third mode, whereby the coolant circulates starting from the device requiring the lower cooling temperature in the order of increasing the required cooling temperature to the second pump12.

Thus, this embodiment can shift the circulation through the respective temperature adjustment devices15,16,17, and18between the low-temperature coolant and the high-temperature coolant in accordance with the required coolant temperature thereof, which can appropriately cool the temperature adjustment devices15,16,17, and18, while achieving the energy saving.

Second Embodiment

Although in the first embodiment, the exhaust gas cooler17is connected between the outlet19dof the first switching valve19and the inlet20bof the second switching valve20, in a second embodiment, as shown inFIG. 16, a condenser50(temperature adjustment device) and a heater core51are connected between the outlet19dof the first switching valve19and the inlet20bof the second switching valve20.

The condenser50is a high-pressure side heat exchanger for condensing a high-pressure refrigerant by exchanging heat between the coolant and the high-pressure refrigerant discharged from the compressor23, thereby heating the coolant. The coolant inlet side of the condenser50is connected to the outlet19dof the first switching valve19.

The heater core51is a heat exchanger for heating that heats the blast air by exchanging heat between the coolant and the blast air having passed through the cooler core18. The heater core51is disposed downstream of the air flow of the cooler core18within the casing27of the indoor air conditioning unit.

The coolant inlet side of the heater core51is connected to the coolant outlet side of the condenser50. The coolant outlet side of the heater core51is connected to the inlet20bof the second switching valve20.

Although in the first embodiment, the coolant cooler14is connected between the discharge side of the first pump11and the inlet19bof the first switching valve19, in this embodiment, the coolant cooler14is connected between the first switching valve19and the cooler core18. Specifically, the coolant inlet side of the coolant cooler14is connected to the outlet19cof the first switching valve19, and the coolant outlet side of the coolant cooler14is connected to the coolant inlet side of the cooler core18.

The first switching valve19is configured to be capable of switching among the five types of communication states between the inlets19aand19band the outlets19c,19d,19e, and19f. The second switching valve20is also configured to be capable of switching among five types of communication states between the inlets20a,20c, and20dand the outlets20e, and20f.

FIG. 17shows the operation (first mode) of the cooling system10when the first and second switching valves19and20are switched to a first state.

In the first state, the first switching valve19connects the inlet19awith the outlets19d,19e, and19f, and also connects the inlet19bwith the outlet19c. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19d,19e, and19fas indicated by alternate long and short dash lines with arrows inFIG. 17, and also allows the coolant entering the inlet19bto flow out of the outlet19cas indicated by a solid arrow inFIG. 17.

In the first state, the second switching valve20connects the inlets20b,20c, and20dwith the outlet20e, and also connects the inlet20awith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlets20b,20c, and20dto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIG. 17, and also allows the coolant entering the inlet20ato flow out of the outlet20fas a solid arrow inFIG. 17.

FIG. 18shows the operation (second mode) of the cooling system10when the first and second switching valves19and20are switched to a second state.

In the second state, the first switching valve19connects the inlet19awith the outlets19d, and19f, and also connects the inlet19bwith the outlets19cand19e. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19dand19fas indicated by dashed-dotted lines with arrows inFIG. 18, and also allows the coolant entering the inlet19bto flow out of the outlets19cand19eas indicated by solid arrows inFIG. 18.

In the second state, the second switching valve20connects the inlets20band20dwith the outlet20eand also connects the inlets20a, and20cwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlets20band20dto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIG. 18, and also allows the coolant entering the inlets20aand20cto flow out of the outlet20fas indicated by solid lines with an arrow inFIG. 18.

FIG. 19shows the operation (third mode) of the cooling system10when the first and second switching valves19and20are switched to a third state.

In the third state, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19c,19e, and19f. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 19, and also allows the coolant entering the inlet19bto flow out of the outlets19c,19e, and19fas indicated by solid arrows inFIG. 19.

In the third state, the second switching valve20connects the inlet20bwith the outlet20eand also connects the inlets20a,20c, and20dwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlet20bto flow out of the outlet20eas indicated by an alternate long and short dash line with an arrow inFIG. 19, and also allows the coolant entering the inlets20a,20c, and20dto flow out of the outlet20fas indicated by a solid arrow inFIG. 19.

FIG. 20shows the operation (fourth mode) of the cooling system10when the first and second switching valves19and20are switched to a fourth state.

In the fourth state, the first switching valve19connects the inlet19awith the outlets19c,19e, and19f, and also connects the inlet19bwith the outlet19d. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19c,19e, and19fas indicated by solid arrows inFIG. 20, and also allows the coolant entering the inlet19bto flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 20.

In the fourth state, the second switching valve20connects the inlet20bwith the outlet20fand also connects the inlets20a,20c, and20dwith the outlet20e. Thus, the second switching valve20allows the coolant entering the inlets20a,20c, and20dto flow out of the outlet20eas indicated by solid arrows inFIG. 20, and also allows the coolant entering the inlet20bto flow out of the outlet20fas indicated by an alternate long and short dash line with an arrow inFIG. 20.

FIG. 21shows the operation (fifth mode) of the cooling system10when the first and second switching valves19and20are switched to a fifth state.

In the fifth state, the first switching valve19connects the inlet19awith the outlet19c, and also connects the inlet19bwith the outlets19d,19e, and19f. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlet19cas indicated by a broken line with an arrow inFIG. 21, and also allows the coolant entering the inlet19bto flow out of the outlets19d,19e, and19fas indicated by an alternate long and short dash line with an arrow inFIG. 21.

In the fifth state, the second switching valve20connects the inlet20awith the outlet20eand also connects the inlets20b,20c, and20dwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlet20ato flow out of the outlet20eas indicated by a broken line with an arrow inFIG. 21, and also allows the coolant entering the inlets20b,20c, and20dto flow out of the outlet20fas indicated by alternate long and short dash lines with arrows inFIG. 21.

The specific structures of the coolant cooler14and the condenser50in this embodiment will be described below with reference toFIG. 22. The coolant cooler14and condenser50are included in one heat exchanger52of the tank-and-tube type. One half of the heat exchanger52constitutes the coolant cooler14, while the other half of the heat exchanger52constitutes the condenser50.

The heat exchanger52includes a heat exchanger core52a, tank portions52band52c, and a partition portion52d. The heat exchanger core52aincludes a plurality of tubes through which the coolant and the refrigerant independently flow. The tubes are stacked on each other in parallel.

The tank portions52band52care disposed on both sides of the tubes to distribute and collect the coolant and refrigerant with respect to the tubes. The internal spaces of the tank portions52band52care partitioned into a space for allowing the coolant to flow therethrough, and another space for allowing the refrigerant to flow therethrough by a partition member (not shown).

The partition portion52dpartitions the insides of the tank portions52band52cinto two spaces in the stacking direction of the tubes (in the left-right direction ofFIG. 22). One side of the heat exchanger52(on the right side ofFIG. 22) in the stacking direction of the tubes with respect to the partition portion52dconstitutes the coolant cooler14, whereas the other side of the heat exchanger52(on the left side ofFIG. 22) in the stacking direction of the tubes with respect to the partition portion52dconstitutes the condenser50.

Members constituting the heat exchanger core52a, the tank portions52band52c, and the partition portion52dare formed of metal (for example, an aluminum alloy), and bonded together by brazing.

One part of the tank portion52bserving as the coolant cooler14is provided with an inlet52efor the coolant and an outlet52ffor the refrigerant. The other part of the tank portion52cserving as the coolant cooler14is provided with an outlet52gfor the coolant and an inlet52hfor the refrigerant.

Thus, in the coolant cooler14, the coolant flows from the inlet52einto the tank portion52b, and is then distributed to the tubes for the coolant by the tank portion52b. The coolants after having passed through the tubes for the coolant are collected into the tank portion52cto flow from the outlet52g.

In the coolant cooler14, the refrigerant flows from the inlet52hinto the tank portion52c, and is then distributed to the tubes for the refrigerant by the tank portion52c. The refrigerants after having passed through the tubes for the coolant are collected into the tank portion52bto flow from the outlet52f.

One part of the tank portion52bserving as the condenser50is provided with an inlet52hfor the coolant and an outlet52ifor the refrigerant. The other part of the tank portion52cserving as the condenser50is provided with an outlet52jfor the coolant and an inlet52kfor the refrigerant.

Thus, in the condenser50, the coolant flows from the inlet52hinto the tank portion52b, and is then distributed to the tubes for the coolant by the tank portion52b. The coolants after having passed through the tubes for the coolant are collected into the tank portion52cto flow from the outlet52j.

In the condenser50, the refrigerant flows from the inlet52kinto the tank portion52c, and is then distributed to the tubes for the refrigerant by the tank portion52c. The refrigerants after having passed through the tubes for the refrigerant are collected into the tank portion52bto flow from the outlet52i.

The heat exchanger52is not limited to the tank-and-tube type heat exchanger, and can be applied to other types of heat exchangers. For example, a laminate-type heat exchanger including a lamination of a number of plate-like members may be adopted.

A control process executed by the controller40of this embodiment will be described with reference toFIG. 23. The controller40executes a computer program according to a flowchart ofFIG. 23.

First, in step S100, it is determined whether the air conditioning switch44is turned on or not. When the air conditioner44is determined to be turned on, the cooling is considered to be necessary, and then the operation proceeds to step S110. In step S110, it is determined whether the temperature of coolant detected by the water temperature sensor43is lower than 40 degrees or not.

When the temperature of coolant detected by the water temperature sensor43is determined to be lower than 40 degrees, the temperature of the coolant (intermediate-temperature coolant) cooled by the outside air in the radiator13is considered to be low, and then the operation proceeds to step S120. In step S120, the first mode shown inFIG. 17is performed.

In the first mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the first state shown inFIG. 17to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlets19d,19e, and19f, and also connects the inlet19bwith the outlet19c. The second switching valve20connects the inlets20b,20c, and20dwith the outlet20e, and also connects the inlet20awith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the battery cooler15, the inverter cooler16, the condenser50, the heater core51, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, and the cooler core18.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 17, the coolant discharged from the first pump11is branched by the first switching valve19into the battery cooler15, the inverter16, and the condenser50to flow in parallel through the battery cooler15, the inverter cooler16, and the condenser50. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51, through the battery cooler15, and through the inverter cooler16are collected by the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by a solid arrow inFIG. 17, the coolant discharged from the second pump12flows through the coolant cooler14and the cooler core18in series via the first switching valve19, and is then sucked into the second pump12via the second switching valve20.

Thus, in the first mode, the intermediate-temperature coolant cooled by the radiator13flows through the battery cooler15, the inverter cooler16, the condenser50, and the heater core51, whereas the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18.

Thus, in the battery cooler15and the inverter cooler16, the battery and inverter are cooled by the intermediate-temperature coolant. In the condenser50, the intermediate-temperature coolant is heated by exchanging heat with the high-pressure refrigerant of the refrigeration cycle22. In the cooler core18, the blast air into the vehicle interior is cooled by exchanging heat between the low-temperature coolant and the blast air into vehicle interior.

The intermediate-temperature coolant heated by the condenser50exchanges heat with the blast air having passed through the cooler core18when flowing through the heater core51. Thus, the heater core51heats the blast air having passed through the cooler core18. That is, the blast air cooled and dehumidified by the cooler core18can be heated by the heater core51to form a conditioned air at a desired temperature.

For example, when the outside air temperature is about 15° C., the intermediate-temperature coolant cooled by the outside air in the radiator13becomes at about 25° C., so that the intermediate-temperature coolant can sufficiently cool the battery and the inverter.

The low-temperature coolant cooled by the low-pressure refrigerant of the refrigeration cycle22in the coolant cooler14becomes at about 0° C., so that the low-temperature coolant can sufficiently cool the blast air into the vehicle interior.

In the first mode, the battery and the inverter are cooled by the outside air, which can effectively achieve the energy saving as compared to the case in which the battery and the inverter are cooled by the low-pressure refrigerant of the refrigeration cycle22.

In contrast, in step S110, when the temperature of the coolant detected by the water temperature sensor43is determined not to be lower than 40 degrees, the temperature of the intermediate-temperature coolant is considered to be higher, and then the operation proceeds to step S130. In step S130, it is determined whether or not the temperature of the coolant detected by the water temperature sensor43is 40 degrees or more and less than 50 degrees.

When the temperature of the coolant detected by the water temperature sensor43is determined to be 40 degrees or more and less than 50 degrees, the operation proceeds to step S140, in which the second mode is performed as shown inFIG. 18.

In the second mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the second state shown inFIG. 18to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlets19dand19f, and also connects the inlet19bwith the outlets19cand19e. The second switching valve20connects the inlets20band20dwith the outlet20e, and also connects the inlets20aand20cwith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the inverter cooler16, the condenser50, the heater core51, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, and the battery cooler15.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 18, the coolant discharged from the first pump11is branched into the inverter cooler16and the condenser50by the first switching valve19to flow in parallel through the inverter cooler16and the condenser50. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51and through the inverter cooler16are collected by the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 18, the coolant discharged from the second pump12is branched into the coolant cooler14and the battery cooler15by the first switching valve19to flow in parallel through the coolant cooler14and the battery cooler15. The coolant flowing through the coolant cooler14flows in series through the cooler core18. The coolants flowing through the cooler core18and through the battery cooler15are collected by the second switching valve20to be sucked into the second pump12.

Thus, in the second mode, the intermediate-temperature coolant cooled by the radiator13flows through the inverter cooler16, the condenser50, and the heater core51, whereas the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18and the battery cooler15.

Thus, the inverter can be cooled by the intermediate-temperature coolant, and the battery can be cooled by the low-temperature coolant. Additionally, like the first mode, the blast air cooled and dehumidified by the cooler core18is heated by the heater core51, which can make the conditioned air at the desired temperature.

For example, when the outside air temperature is about 30° C., the intermediate-temperature coolant cooled by the outside air in the radiator13becomes at a temperature of about 40° C., so that the intermediate-temperature coolant can sufficiently cool the inverter.

The low-temperature coolant cooled by the low-pressure refrigerant of the refrigeration cycle22in the coolant cooler14becomes at about 0° C., so that the battery and the blast air into the vehicle interior can be sufficiently cooled by the low-temperature coolant.

Since in the second mode the battery is cooled by the low-pressure refrigerant of the refrigeration cycle22, the battery can be sufficiently cooled even when the outside air cannot cool the battery adequately because of the high temperature of the outside air.

In step S130, when the temperature of coolant detected by the water temperature sensor43is determined to be 40 degrees or more and less than 50 degrees, the temperature of the intermediate-temperature coolant is considered to be very high, and then the operation proceeds to step S150. In step S150, the third mode shown inFIG. 19is performed.

In the third mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the third state shown inFIG. 19to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlet19dand also connects the inlet19bwith the outlets19c,19e, and19f. The second switching valve20connects the inlet20bwith the outlet20e, and also connects the inlets20a,20c, and20dwith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the condenser50, the heater core51, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, the battery cooler15, and the inverter cooler16.

That is, as indicated by an alternate long and short dash line with an arrow inFIG. 19, the coolant discharged from the first pump11flows through the condenser50and heater core51in series via the first switching valve19, and then through the radiator13via the second switching valve20, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 19, the coolant discharged from the second pump12is branched into the coolant cooler14, the battery cooler15, and the inverter cooler16by the first switching valve19. The coolant flowing through the coolant cooler14flows in series through the cooler core18. The coolants flowing through the cooler core18, through the battery cooler15, and through the inverter cooler16are collected by the second switching valve20to be sucked into the second pump12.

Accordingly, in the third mode, the intermediate-temperature coolant cooled by the radiator13flows through the condenser50and the heater core51, whereas the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18, the battery cooler15, and the inverter cooler16.

Thus, the battery and the inverter can be cooled by the low-temperature coolant, and like the first and second modes, the blast air cooled and dehumidified by the cooler core18is heated by the heater core51, which can make the conditioned air at the desired temperature.

For example, when the outside air temperature is about 40° C., the intermediate-temperature coolant cooled by the outside air in the radiator13becomes at about 50° C. The low-temperature coolant cooled by the low-pressure refrigerant of the refrigeration cycle22in the coolant cooler14becomes at about 0° C., so that the blast air into the vehicle interior, the battery, and the inverter can be sufficiently cooled by the low-temperature coolant.

Since in the third mode the battery and the inverter are cooled by the low-pressure refrigerant of the refrigeration cycle22, the battery and the inverter can be sufficiently cooled even when the outside air cannot cool the battery and the inverter adequately because of the very high temperature of the outside air.

When the air conditioning switch44is determined not to be turned on in step S100, the cooling is considered not to be necessary, and then the operation proceeds to step S160. In step S160, it is determined whether the outside air temperature detected by the outside air sensor42is lower than 15 degrees or not.

When the outside air temperature detected by the outside air sensor42is determined to be 15 degrees or less, the high heating capacity is considered to be necessary, and then the operation proceeds to step S170, in which a fourth mode is performed as shown inFIG. 20.

In the fourth mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the fourth state shown inFIG. 20to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlets19c,19e, and19f, and also connects the inlet19bwith the outlet19d. The second switching valve20connects the inlets20a,20c, and20dwith the outlet20e, and also connects the inlet20bwith the outlet20f.

Accordingly, a first coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, the cooler core18, the battery cooler15, the inverter cooler16, and the radiator13, whereas a second coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the condenser50, and the heater core51.

That is, as indicated by solid arrows inFIG. 20, the coolant discharged from the first pump11is branched into the coolant cooler14, the battery cooler15, and the inverter cooler16by the first switching valve19. The coolant flowing through the coolant cooler14flows in series through the cooler core18. The coolants flowing through the cooler core18, through the battery cooler15, and through the inverter cooler16are collected by the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by an alternate long and short dash line with an arrow inFIG. 20, the coolant discharged from the second pump12flows through the condenser50and the heater core51in series via the first switching valve19, and is then sucked into the second pump12via the second switching valve20.

Thus, in the fourth mode, the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18, the battery cooler15, and the inverter cooler16, which can cool the blast air into the vehicle interior, the battery, and the inverter by the low-temperature coolant.

In the fourth mode, the low-temperature coolant cooled by the coolant cooler14flows through the radiator13, allowing the coolant to absorb heat from the outside air in the radiator13. Then, the coolant having absorbed heat from the outside air in the radiator13exchanges heat with the refrigerant of the refrigeration cycle22in the coolant cooler14to dissipate heat therefrom. Thus, in the coolant cooler14, the refrigerant of the refrigeration cycle22absorbs heat from the outside air via the coolant.

The refrigerant having absorbed heat from the outside air in the coolant cooler14exchanges heat with the coolant of the intermediate-temperature coolant circuit in the condenser50, whereby the coolant of the intermediate-temperature coolant circuit is heated. The coolant of the intermediate-temperature circuit heated by the condenser50exchanges heat with the blast air having passed through the cooler core18in flowing through the heater core51, thereby dissipating heat therefrom. Thus, the heater core51heats the blast air having passed through the cooler core18. Accordingly, the fourth mode can achieve heat pump heating that heats the vehicle interior by absorbing heat from the outside air.

For example, when the outside air temperature is 10° C., the intermediate-temperature coolant heated by the condenser50becomes at about 50° C., so that the blast air having passed through the cooler core18can be sufficiently heated by the intermediate-temperature coolant.

The low-temperature coolant cooled by the low-pressure refrigerant of the refrigeration cycle22in the coolant cooler14becomes at about 0° C., so that the battery and the inverter can be sufficiently cooled by the low-temperature coolant.

Note that the fourth mode can achieve the dehumidification heating, by allowing the heater core51to heat the blast air cooled and dehumidified by the cooler core18.

In the following step S180, it is determined whether or not the inside air temperature detected by the inside air sensor41is 25 degrees or more. When the inside air temperature detected by the inside air sensor41is determined not to be 25 degrees or more, the high heating capacity is considered to be necessary, and then the operation returns to step S180. Thus, until the inside air temperature is increased to 25 degrees or more, the fourth mode is performed.

When the inside air temperature detected by the inside air sensor41is determined to be 25 degrees or more, the high heating capacity is considered not to be necessary, and then the operation proceeds to step S190, in which a fifth mode is performed as shown inFIG. 21.

In the fifth mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20becomes the fifth state shown inFIG. 21.

Thus, the first switching valve19connects the inlet19awith the outlet19cand also connects the inlet19bwith the outlets19d,19e, and19f. The second switching valve20connects the inlet20awith the outlet20e, and also connects the inlets20b,20c, and20dwith the outlet20f.

Accordingly, a first coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, the cooler core18, and the radiator13, whereas a second coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the battery cooler15, the inverter cooler16, the condenser50, and the heater core51.

At this time, the second pump12is operated to thereby stop the first pump11and compressor23. Thus, in the first coolant circuit indicated by dashed arrows inFIG. 21, the coolant does not circulate therethrough.

On the other hand, as indicated by alternate long and short dash lines with arrows inFIG. 21, in the second coolant circuit, the coolant discharged from the second pump12is branched into the battery cooler15, the inverter cooler16, and the condenser50by the first switching valve19. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51, through the battery cooler15, and through the inverter cooler16are collected by the second switching valve20to be sucked into the second pump12.

Thus, in the fifth mode, the coolant which has absorbed heat from the battery in the battery cooler15and the coolant which has absorbed heat from the inverter in the inverter cooler16flow through the heater core51, so that the blast air into the vehicle interior can be heated by exhaust heat from the battery and inverter.

For example, when the outside air temperature is 10° C., the coolant heated by the battery cooler15and the inverter cooler16becomes at about 30° C., whereby the blast air into the vehicle interior can be heated to 25 degrees or more with the inside air temperature maintained at 25 degrees or more.

In this embodiment, when the outside air temperature is lower than a predetermined temperature (15° C. in this embodiment), the forth mode or the fifth mode can be carried out to perform heating.

In the fourth mode, the coolant circulates between the coolant cooler14and the first pump11, whereas the coolant heat medium circulates between the condenser50and the second pump12.

Thus, the coolant cooled by the coolant cooler14flows through the radiator13, so that the refrigerant of the refrigeration cycle22in the coolant cooler14can absorb heat from the outside air via the coolant flowing through the radiator13. Thus, the heat of the outside air can be pumped up from the coolant cooler14(low-pressure side heat exchanger) of the refrigeration cycle22to the condenser50(high-pressure side heat exchanger).

The heat of the outside air pumped up by the refrigeration cycle22can heat the blast air into the vehicle interior by use of the heater core51, which can achieve the heat pump heating which heats the vehicle interior by absorption of the heat from the outside air.

In the fifth mode, the coolant circulates between each of the battery cooler15and the heater core51, and the second pump12, whereby the operation of the first pump11is stopped. Thus, the coolant absorbs heat from the battery in the battery cooler15, and the coolant which has absorbed the heat from the battery heats the blast air into the vehicle interior by the heater core51, so that the exhaust heat from the battery can be used to heat the vehicle interior.

Third Embodiment

In the second embodiment, the low-pressure refrigerant of the refrigeration cycle22is evaporated by the coolant cooler14, thereby cooling the blast air into the vehicle interior by the cooler core18. However, in a third embodiment, as shown inFIG. 24, the low-pressure refrigerant of the refrigeration cycle22is evaporated in the coolant cooler14and an evaporator55, thereby cooling the blast air into the vehicle interior by the evaporator55of the refrigeration cycle22.

The evaporator55allows the refrigerant to flow in parallel to the coolant cooler14. Specifically, the refrigerant cycle22has a branch portion56for refrigerant flow that is located between the refrigerant discharge side of the compressor23and the refrigerant inlet side of the expansion valve25, and a collection portion57for refrigerant flow that is located between the refrigerant outlet side of the coolant cooler14and the refrigerant suction side of the compressor23. An expansion valve58and the evaporator55are connected between the branch portion56and the collection portion57.

The expansion valve58is a decompression device for decompressing and expanding a liquid-phase refrigerant branched by the branch portion56. The evaporator55is adapted to evaporate a low-pressure refrigerant so as to cool the blast air by exchanging heat between the blast air into the vehicle interior and the low-pressure refrigerant decompressed and expanded by the expansion valve25.

An electromagnetic valve59(opening and closing valve) is connected between the branch portion56and the expansion valve25. When the electromagnetic valve59is opened, the refrigerant discharged from the compressor23flows through the expansion valve25and the coolant cooler14. When the electromagnetic valve59is closed, the flow of refrigerant toward the expansion valve25and the coolant cooler14is interrupted. The operation of the electromagnetic valve59is controlled by the controller40.

The refrigeration cycle22includes a supercooler60. The supercooler60is a heat exchanger for further cooling the liquid-phase refrigerant to enhance a supercooling degree of the refrigerant by exchanging heat between the coolant and the liquid-phase refrigerant condensed by the condenser50.

The coolant inlet side of the supercooler60is connected to the outlet19eof the first switching valve19. The coolant outlet side of the supercooler60is connected to the coolant inlet side of the battery cooler15.

In this embodiment, the battery cooler15and the battery are accommodated in an insulating container formed of thermal insulating material. Thus, cold energy stored in the battery can be prevented from escaping outward, thereby keeping the battery cold.

The first switching valve19is configured to be capable of switching between two types of communication states between the inlets19aand19band the outlets19c,19d,19e, and19f. The second switching valve20is also configured to be capable of switching between two types of communication states between the inlets20a,20b,20c, and20dand the outlets20e, and20f.

FIG. 25shows the operation (first mode) of the cooling system10when the first and second switching valves19and20are switched to a first state, and the electromagnetic valve59is switched to an opened state.FIG. 26shows the operation (second mode) of the cooling system10when the first and second switching valves19and20are switched to the first state, and the electromagnetic valve59is switched to a closed state.

In the first and second states, the first switching valve19connects the inlet19awith the outlets19d, and19f, and also connects the inlet19bwith the outlets19cand19e. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19d, and19fas indicated by alternate long and short dash lines with arrows inFIGS. 25 and 26, and also allows the coolant entering the inlet19bto flow out of the outlets19cand19eas indicated by solid arrows inFIGS. 25 and 26.

In the first and second states, the second switching valve20connects the inlets20band20dwith the outlet20eand also connects the inlets20a, and20cwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlets20b, and20dto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIGS. 25 and 26, and also allows the coolant entering the inlets20aand20cto flow out of the outlet20fas indicated by solid arrows inFIGS. 25 and 26.

FIG. 27shows the operation (third mode) of the cooling system10when the first and second switching valves19and20are switched to a third state.

In the third state, the first switching valve19connects the inlet19awith the outlets19c, and19f, and also connects the inlet19bwith the outlet19d, thereby closing the outlet19e. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19cand19fas indicated by solid arrows inFIG. 27, and also allows the coolant entering the inlet19bto flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 27, thereby preventing the coolant from flowing out of the outlet19e.

In the third state, the second switching valve20connects the inlets20aand20dwith the outlet20eand also connects the inlet20bwith the outlet20f, thereby closing the inlet20c. Thus, the second switching valve20allows the coolant entering the inlets20aand20dto flow out of the outlet20eas indicated by solid arrows inFIG. 27, and also allows the coolant entering the inlet20bto flow out of the outlet20fas indicated by an alternate long and short dash line with an arrow inFIG. 27, thereby preventing the coolant from flowing out of the inlet20c.

The specific structures of the coolant cooler14, the condenser50, and the supercooler60in this embodiment will be described below with reference toFIG. 28.

The coolant cooler14, the condenser50, and the supercooler60are included in one heat exchanger61of the tank-and-tube type. Specifically, the supercooler60is disposed between the coolant cooler14and the condenser50.

The heat exchanger61includes a heat exchanger core61a, tank portions61band61c, and two partition portions61dand61d. The heat exchanger core61aincludes a plurality of tubes through which the coolant and the refrigerant independently flow. The tubes are stacked on each other in parallel.

The tank portions61band61care disposed on both sides of the tubes to distribute and collect the coolant and refrigerant with respect to the tubes. The internal spaces of the tank portions61band61care partitioned into a space for allowing the coolant to flow therethrough, and another space for allowing the refrigerant to flow therethrough by a partition member (not shown).

The two partition portions61dand61dpartition the insides of the tank portions61band61cinto three spaces in the stacking direction of the tubes (in the left-right direction ofFIG. 28). One side of the heat exchanger52(on the right side ofFIG. 28) in the stacking direction of the tubes with respect to the partition portion61dconstitutes the coolant cooler14, whereas the other side of the heat exchanger52(on the left side ofFIG. 28) in the stacking direction of the tubes with respect to the partition portion61dconstitutes the condenser50, whereby a gap between the partitions61dand61dserves as the supercooler60.

Members constituting the heat exchanger core61a, the tank portions61band61c, and the partition portion61dare formed of metal (for example, an aluminum alloy), and bonded together by brazing.

One part of the tank portion61bserving as the coolant cooler14is provided with an inlet61efor the coolant and an outlet61ffor the refrigerant. The other part of the tank portion61cserving as the coolant cooler14is provided with an outlet61gfor the coolant and an inlet61hfor the refrigerant.

Thus, in the coolant cooler14, the coolant flows from the inlet61einto the tank portion61b, and is then distributed to the tubes for the coolant by the tank portion61b. The coolants after having passed through the tubes for the coolant are collected into the tank portion61cto flow from the outlet61g.

In the coolant cooler14, the refrigerant flows from the inlet61hinto the tank portion61c, and is then distributed to the tubes for the refrigerant by the tank portion61c. The refrigerants after having passed through the tubes for the refrigerant are collected into the tank portion61bto flow from the outlet61f.

One part of the tank portion61bserving as the condenser50is provided with an inlet61ifor the coolant. A hole61jfor allowing the refrigerant to flow therethrough is formed in a part of the partition portion61dfor partitioning the inner space of the tank portion61binto a tank space for the condenser50and another tank space for the supercooler60. Another part of the other tank portion61cserving as the condenser50is provided with an outlet61kfor the coolant and an inlet611for the refrigerant.

Thus, in the condenser50, the coolant flows from the inlet61iinto the tank portion61b, and is then distributed to the tubes for the coolant by the tank portion61b. The coolants after having passed through the tubes for the coolant are collected into the tank portion61cto flow from the outlet61k.

In the condenser50, the refrigerant flows from the inlet611into the tank portion61c, and is then distributed to the tubes for the refrigerant by the tank portion61c. The refrigerants after having passed through the tubes for the refrigerant are collected into the tank portion61bto flow from the supercooler60via the hole61jof the partition portion61d.

One part of the tank portion61bserving as the supercooler60is provided with an outlet61mfor the coolant. Another part of the other tank portion61cserving as the supercooler60is provided with an inlet61nfor the coolant and an outlet610for the refrigerant.

Thus, in the condenser60, the coolant flows from the inlet61ninto the tank portion61c, and is then distributed to the tubes for the coolant by the tank portion61c. The coolants after having passed through the tubes for the coolant are collected into the tank portion61bto flow from the outlet61m.

In the supercooler60, the refrigerant flows into the tank portion61bthrough the hole61jof the partition portion61d, and is then distributed to the tubes for the refrigerant by the tank portion61b. The refrigerants after having passed through the tubes for the refrigerant are collected into the tank portion61cto flow from the outlet610.

Now, the operation of the above-mentioned structure will be described. When the battery is charged with an external power source, the controller40performs the first mode shown inFIG. 25.

In the first mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the first state shown inFIG. 25to operate the first and second pumps11and12and the compressor23, thereby switching the electromagnetic valve59to the opened state.

Thus, the first switching valve19connects the inlet19awith the outlets19dand19f, and also connects the inlet19bwith the outlets19cand19e. The second switching valve20connects the inlets20band20dwith the outlet20e, and also connects the inlets20aand20cwith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the inverter cooler16, the condenser50, the heater core51, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the supercooler60, and the battery cooler15.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 25, the coolant discharged from the first pump11is branched into the inverter cooler16and the condenser50by the first switching valve19to flow in parallel through the inverter cooler16and the condenser50. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51and through the inverter cooler16are collected by the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 25, the coolant discharged from the second pump12is branched into the coolant cooler14and the supercooler60by the first switching valve19to flow in parallel through the coolant cooler14and the supercooler60. The coolant flowing through the supercooler60flows in series through the battery cooler15. The coolants flowing through the battery cooler15and through the coolant cooler14are collected by the second switching valve20to be sucked into the second pump12.

In this way, in the first mode, the intermediate-temperature coolant cooled by the radiator13flows through the inverter cooler16, the condenser50, and the heater core51, whereas the low-temperature coolant cooled by the coolant cooler14flows through the supercooler60and the battery cooler15.

As a result, the inverter and the high-pressure refrigerant of the condenser50are cooled by the intermediate-temperature coolant, and the battery and the liquid-phase refrigerant of the supercooler60are cooled by the low-temperature coolant. Thus, the cold energy is stored in the battery.

When the battery is charged with the external power source, the compressor23of the refrigeration cycle22is driven by power supplied from the external power source. Thus, in the first mode, the cold energy is stored in the battery using the power supplied from the external power source.

In the first mode, the evaporator55exchanges heat between the blast air into the vehicle interior and the low-pressure refrigerant of the refrigeration cycle22to thereby cool the blast air into the vehicle interior. In the first mode, the condenser50exchanges heat between the intermediate-temperature coolant and the high-pressure refrigerant of the refrigeration cycle22to thereby heat the intermediate-temperature coolant, whereas the heater core51exchanges heat between the blast air into the vehicle interior and the intermediate-temperature coolant to thereby heat the blast air into the vehicle interior.

Thus, the conditioned air at the desired temperature can be made to adjust the temperature of air in the vehicle interior. For example, when the battery is charged before a passenger rides on a vehicle, pre-air conditioning can be carried out to perform air conditioning of the vehicle interior before the passenger rides on.

When the battery is not charged with the external power source and the interior of the vehicle needs cooling, the controller40performs the second mode shown inFIG. 26.

In the second mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the first state shown inFIG. 26to operate the first and second pumps11and12and the compressor23, thereby switching the electromagnetic valve59to the closed state. That is, the second mode has the same states of the first and second switching valves19and20as those in the first mode, but differs from the first mode in that the electromagnetic valve59is closed.

Thus, the low-pressure refrigerant of the refrigeration cycle22does not flow through the coolant cooler14, and as a result the coolant is not cooled by the coolant cooler14. However, the coolant is cooled by the cold energy stored in the battery in the first mode, at the battery cooler15.

Since the low-temperature coolant cooled by the battery cooler15flows through the supercooler60, the liquid-phase refrigerant (high-pressure refrigerant) of the supercooler60is cooled by the low-temperature coolant.

Thus, in the second mode, the cold energy stored in the battery can be used to supercool the high-pressure refrigerant of the refrigeration cycle22, which can improve the efficiency of the refrigeration cycle22, thereby achieving the energy saving.

Note that in the second mode, the low-temperature coolant may be cooled by the coolant cooler14with the electromagnetic valve59opened.

When the battery is at a predetermined temperature (for example, 40° C.) or less, and thus does not need cooling, and when the vehicle interior needs to be heated, the controller40performs the third mode shown inFIG. 27.

In the third mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the second state shown inFIG. 27to operate the first and second pumps11and12and the compressor23, thereby switching the electromagnetic valve59to the opened state.

Thus, the first switching valve19connects the inlet19awith the outlets19c, and19f, and also connects the inlet19bwith the outlet19d, thereby closing the outlet19e. The second switching valve20connects the inlets20aand20dwith the outlet20e, and also connects the inlet20bwith the outlet20f, thereby closing the inlet20c.

Accordingly, a first coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, the inverter cooler16, and the radiator13, whereas a second coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the condenser50, and the heater core51.

That is, as indicated by solid arrows inFIG. 27, the coolant discharged from the first pump11is branched into the coolant cooler14, and the inverter cooler16by the first switching valve19to flowing through the coolant cooler14and the inverter cooler16in parallel. The coolants flowing through the coolant cooler14, and through the inverter cooler16are collected by the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by an alternate long and short dash line with an arrow inFIG. 27, the coolant discharged from the second pump12flows through the condenser50and the heater core51in series via the first switching valve19, and is then sucked into the second pump12via the second switching valve20.

Thus, in the third mode, the low-temperature coolant cooled by the coolant cooler14flows through the inverter cooler16, which can cool the inverter by the low-temperature coolant.

In this case, the battery is at a predetermined temperature (for example, 40° C.) or less, and thus does not need to be cooled, so that the circulation of the coolant to the battery cooler15is stopped.

In the third mode, the low-temperature coolant cooled by the coolant cooler14flows through the radiator13, allowing the coolant to absorb heat from the outside air in the radiator13. Then, the coolant that has absorbed heat from the outside air in the radiator13exchanges heat with the refrigerant of the refrigeration cycle22in the coolant cooler14to dissipate heat therefrom. Thus, in the coolant cooler14, the refrigerant of the refrigeration cycle22absorbs heat from the outside air via the coolant.

The refrigerant that has absorbed heat from the outside air in the coolant cooler14exchanges heat with the coolant of the intermediate-temperature coolant circuit in the condenser50, whereby the coolant of the intermediate-temperature coolant circuit is heated. The coolant of the intermediate-temperature circuit heated by the condenser50exchanges heat with the blast air having passed through the evaporator55in flowing through the heater core51, thereby dissipating heat therefrom. Thus, the heater core51heats the blast air after having passed through the evaporator55. Accordingly, the fourth mode can achieve heat pump heating that heats the vehicle interior by absorbing heat from the outside air.

The blast air heated by the heater core51is a dried cool air cooled and dehumidified by the low-pressure refrigerant of the refrigeration cycle22in the evaporator55. Thus, in the third mode, the dehumidification heating can be performed.

Alternatively, when the temperature of the battery increases in the third mode, the intermediate-temperature coolant or low-temperature coolant may circulate into the battery cooler15, thereby cooling the battery.

In this embodiment, when the battery is charged with the electric power supplied from the external power source, the electromagnetic valve59is opened to allow the low-pressure refrigerant of the refrigeration cycle to flow into the coolant cooler14, so that the coolant cooled by the coolant cooler14flows through the battery cooler15to thereby cool the battery. Thus, the cold energy made by the refrigeration cycle22can be stored in the battery.

After the battery is charged with the electric power supplied from the external power source, the coolant flowing through the battery cooler15flows through the supercooler60, so that the refrigerant flowing through the supercooler60can be cooled by the cold energy stored in the battery, further improving the efficiency of the refrigeration cycle22. At this time, the electromagnetic valve59is closed to prevent the low-pressure refrigerant of the refrigeration cycle from flowing into the coolant cooler14, thereby decreasing a cooling load on the refrigeration cycle22.

Thus, for example, when the external power source cannot be used during traveling of the vehicle, the cold energy stored in the battery can be used for cooling of the temperature adjustment devices, thereby decreasing the power consumption.

In this embodiment, the supercooler60and the battery cooler15are connected together in series, which can effectively cool the coolant heated through the supercooler60with the cold energy stored in the battery cooler15as compared to the case in which the supercooler60and the battery cooler15are connected together in parallel.

Fourth Embodiment

In a fourth embodiment of the invention, as shown inFIG. 29, an intake air cooler65(temperature adjustment device) is added to the structure of the above third embodiment. The intake air cooler65is a heat exchanger that cools intake air by exchanging heat between the coolant and the intake air at a high temperature compressed by a supercharger for an engine. The intake air is preferably cooled down to about 30° C.

The coolant inlet side of the intake air cooler65is connected to the outlet19gof the first switching valve19. The coolant outlet side of the intake air cooler65is connected to the inlet20gof the second switching valve20.

In this embodiment, the supercooler60is connected to the coolant outlet side of the coolant cooler14and the inlet20aof the second switching valve20.

The first switching valve19is configured to be capable of switching among three types of communication states between the inlets19aand19band the outlets19c,19d,19e,19f, and19g. The second switching valve20is also configured to be capable of switching among three types of communication states between the inlets20a,20b,20c,20d, and20gand the outlets20e, and20f.

FIG. 30shows the operation (first mode) of the cooling system10when the first and second switching valves19and20are switched to a first state.

In the first state, the first switching valve19connects the inlet19awith the outlets19d,19f, and19g, and also connects the inlet19bwith the outlets19cand19e. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19d,19f, and19gas indicated by alternate long and short dash lines with arrows inFIG. 30, and also allows the coolant entering the inlet19bto flow out of the outlets19cand19eas indicated by solid arrows inFIG. 30.

In the first state, the second switching valve20connects the inlets20b,20d, and20gwith the outlet20e, and also connects the inlets20a, and20cwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlets20b,20d, and20gto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIG. 30, and also allows the coolant entering the inlets20aand20cto flow out of the outlet20fas indicated by solid lines with an arrow inFIG. 30.

FIG. 31shows the operation (second mode) of the cooling system10when the first and second switching valves19and20are switched to a second state.

In the second state, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19c,19e,19f, and19g. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 31, and also allows the coolant entering the inlet19bto flow out of the outlets19c,19e,19f, and19gas indicated by solid arrows inFIG. 31.

In the second state, the second switching valve20connects the inlet20bwith the outlet20eand also connects the inlets20a,20c,20d, and20gwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlet20bto flow out of the outlet20eas indicated by an alternate long and short dash line with an arrow inFIG. 31, and also allows the coolant entering the inlets20a,20c,20d, and20gto flow out of the outlet20fas a solid arrow inFIG. 31.

FIG. 32shows the operation (third mode) of the cooling system10when the first and second switching valves19and20are switched to a third state.

In the third state, the first switching valve19connects the inlet19awith the outlets19cand19f, and also connects the inlet19bwith the outlets19d,19e, and19g. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19c, and19fas indicated by solid arrows inFIG. 32, and also allows the coolant entering the inlet19bto flow out of the outlets19d,19e, and19gas indicated by alternate long and short dash lines with arrows inFIG. 32.

In the third state, the second switching valve20connects the inlets20a, and20dwith the outlet20e, and also connects the inlets20b,20c, and20gwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlets20aand20dto flow out of the outlet20eas indicated by solid arrows inFIG. 32, and also allows the coolant entering the inlets20b,20c, and20gto flow out of the outlet20fas the alternate long and short dash line with the arrow inFIG. 32.

Now, the operation of the above-mentioned structure will be described. When the outside air temperature detected by the outside air sensor42is more than 15° C. and less than 40° C., the controller40performs the first mode shown inFIG. 30.

In the first mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the first state shown inFIG. 30to operate the first and second pumps11and12and the compressor23, thereby switching the electromagnetic valve59to the opened state.

Thus, the first switching valve19connects the inlet19awith the outlets19d,19f, and19g, and also connects the inlet19bwith the outlets19cand19e. The second switching valve20connects the inlets20b,20d, and20gwith the outlet20e, and also connects the inlets20aand20cwith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the inverter cooler16, the condenser50, the heater core51, the intake air cooler65, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the supercooler60, and the battery cooler15.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 30, the coolant discharged from the first pump11is branched into the inverter cooler16, the condenser50, and the intake air cooler65by the first switching valve19to flow in parallel through the inverter cooler16, the condenser50, and the intake air cooler65. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51, through the inverter cooler16, and through the intake air cooler65are collected by the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 30, the coolant discharged from the second pump12is branched into the coolant cooler14and the battery cooler15by the first switching valve19to flow in parallel through the coolant cooler14and the battery cooler15. The coolant flowing through the coolant cooler14flows in series through the supercooler60. The coolants flowing through the supercooler60and through the battery cooler15are collected by the second switching valve20to be sucked into the second pump12.

Thus, in the first mode, the intermediate-temperature coolant cooled by the radiator13flows through the inverter cooler16, the condenser50, the heater core51, and the intake air cooler65, whereas the low-temperature coolant cooled by the coolant cooler14flows through the supercooler60and the battery cooler15.

As a result, the inverter, the intake air, and the high-pressure refrigerant of the condenser50are cooled by the intermediate-temperature coolant, and the liquid-phase refrigerant of the supercooler60and the battery are cooled by the low-temperature coolant.

In the first mode, the evaporator55exchanges heat between the blast air into the vehicle interior and the low-pressure refrigerant of the refrigeration cycle22to thereby cool the blast air into the vehicle interior. In the first mode, the condenser50exchanges heat between the intermediate-temperature coolant and the high-pressure refrigerant of the refrigeration cycle22to thereby heat the intermediate-temperature coolant, whereas the heater core51exchanges heat between the blast air into the vehicle interior and the intermediate-temperature coolant to thereby heat the blast air into the vehicle interior. Thus, the conditioned air at the desired temperature can be made to adjust the temperature of air in the vehicle interior.

When the outside air temperature detected by the outside air sensor42is 40° C. or higher, the controller40performs the second mode shown inFIG. 31.

In the second mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the second state shown inFIG. 31to operate the first and second pumps11and12and the compressor23, thereby switching the electromagnetic valve59to the opened state.

Thus, the first switching valve19connects the inlet19awith the outlet19dand also connects the inlet19bwith the outlets19c,19e,19f, and19g. The second switching valve20connects the inlet20bwith the outlet20e, and also connects the inlets20a,20c,20d, and20gwith the outlet20f.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the condenser50, the heater core51, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the supercooler60, the battery cooler15, the inverter cooler16, and the intake air cooler65.

That is, as indicated by an alternate long and short dash line with an arrow inFIG. 31, the coolant discharged from the first pump11flows through the condenser50and the heater core51in series via the first switching valve19, and is then sucked into the first pump11via the second switching valve20.

On the other hand, as indicated by solid arrows inFIG. 31, the coolant discharged from the second pump12is branched into the coolant cooler14, the battery cooler15, the inverter cooler16, and the intake air cooler65by the first switching valve19. The coolant flowing through the coolant cooler14flows in series through the supercooler60. The coolants flowing through the supercooler60, through the battery cooler15, through the inverter cooler16, and through the intake air cooler65are collected by the second switching valve20to be sucked into the second pump12.

Thus, in the second mode, the intermediate-temperature coolant cooled by the radiator13flows through the condenser50and the heater core51, whereas the low-temperature coolant cooled by the coolant cooler14flows through the supercooler60, the battery cooler15, the inverter cooler16, and the intake air cooler65.

As a result, the high-pressure refrigerant of the condenser50is cooled by the intermediate-temperature coolant, and the liquid-phase refrigerant of the supercooler60, the battery, the inverter, and the intake air are cooled by the low-temperature coolant.

In the second mode, the evaporator55exchanges heat between the blast air into the vehicle interior and the low-pressure refrigerant of the refrigeration cycle22to thereby cool the blast air into the vehicle interior. In the second mode, the condenser50exchanges heat between the high-pressure refrigerant of the refrigeration cycle22and the intermediate-temperature coolant to thereby heat the intermediate-temperature coolant, whereas the heater core51exchanges heat between the intermediate-temperature coolant and the blast air into the vehicle interior to thereby heat the blast air into the vehicle interior. Thus, the conditioned air at the desired temperature can be made to adjust the temperature of air in the vehicle interior.

Even in performing the first mode, under sudden acceleration, such as upon startup, the low-temperature coolant is allowed to flow through the intake air cooler65, thereby cooling the intake air with the low-temperature coolant in the same way as the second mode. Thus, even though the intake air temperature is increased due to an increase in supercharging pressure at the time of sudden acceleration, the intake air can be sufficiently cooled to improve the fuel efficiency.

When the outside air temperature detected by the outside air sensor42is 0° C. or lower, the controller40performs the third mode shown inFIG. 32.

In the third mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the third state shown inFIG. 32to operate the first and second pumps11and12and the compressor23, thereby switching the electromagnetic valve59to the opened state.

Thus, the first switching valve19connects the inlet19awith the outlets19cand19fand also connects the inlet19bwith the outlets19d,19e, and19g. The second switching valve20connects the inlets20aand20dwith the outlet20e, and also connects the inlets20b,20c, and20gwith the outlet20f.

Accordingly, the first coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, the supercooler60, the inverter cooler16, and the radiator13, whereas the second coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the battery cooler15, the condenser50, the heater core51, and the intake cooler65.

That is, as indicated by solid arrows inFIG. 32, the coolant discharged from the first pump11is branched into the coolant cooler14and the inverter cooler16by the first switching valve19. The coolant flowing through the coolant cooler14flows in series through the supercooler60. The coolants flowing through the supercooler60and through the inverter cooler16are collected by the second switching valve20to thereby be sucked into the second pump11.

On the other hand, as indicated by alternate long and short dash lines with arrows inFIG. 32, the coolant discharged from the second pump12is branched into the battery cooler15, the condenser50, and the intake air cooler65by the first switching valve19. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51, through the battery cooler15, and through the intake air cooler65are collected by the second switching valve20to be sucked into the second pump12.

In the third mode, the low-temperature coolant cooled by the coolant cooler14flows through the inverter cooler16, which can cool the inverter by the low-temperature coolant.

In the third mode, the low-temperature coolant cooled by the coolant cooler14flows through the radiator13, allowing the coolant to absorb heat from the outside air in the radiator13. Then, the coolant which has absorbed heat from the outside air in the radiator13exchanges heat with the refrigerant of the refrigeration cycle22in the coolant cooler14to dissipate heat therefrom. Thus, in the coolant cooler14, the refrigerant of the refrigeration cycle22absorbs heat from the outside air via the coolant.

The refrigerant which has absorbed heat from the outside air in the coolant cooler14exchanges heat with the coolant of the intermediate-temperature coolant circuit in the condenser50, whereby the coolant of the intermediate-temperature coolant circuit is heated. The coolant of the intermediate-temperature circuit heated by the condenser50exchanges heat with the blast air having passed through the evaporator55in flowing through the heater core51, thereby dissipating heat therefrom. Thus, the heater core51heats the blast air after having passed through the evaporator55. Accordingly, the fourth mode can achieve heat pump heating that heats the vehicle interior by absorbing heat from the outside air.

The blast air heated by the heater core51is a dried cool air cooled and dehumidified by the evaporator55. Thus, in the third mode, the dehumidification heating can be performed.

In the third mode, the intermediate-temperature coolant heated by the condenser50flows through the battery cooler15and the intake air cooler65. Thus, the third mode can improve the output of the battery by heating the battery, and promote the atomization of the fuel by heating the intake air, further improving the fuel efficiency. In particular, at the cold start when fuel is difficult to atomize due to the cold engine, the promotion of the atomization of the fuel can improve the combustion efficiency.

Fifth Embodiment

Although in the second embodiment, the radiator13is connected between the outlet20eof the second switching valve20and the suction side of the first pump11, in a fifth embodiment, as shown inFIG. 33, the radiator13is connected between the outlet19gof the first switching valve19and the inlet20gof the second switching valve20.

The coolant inlet side of the radiator13is connected to the outlet19gof the first switching valve19. The coolant outlet side of the radiator13is connected to the inlet20gof the second switching valve20.

The first switching valve19is configured to be capable of switching between two types of communication states between the inlets19aand19band the outlets19c,19d,19e,19f, and19g. The second switching valve20is also configured to be capable of switching between two types of communication states between the inlets20a,20b,20c,20d, and20gand the outlets20e, and20f.

FIG. 34shows the operation (first mode) of the cooling system10when the first and second switching valves19and20are switched to a first state.

In the first state, the first switching valve19connects the inlet19awith the outlets19dand19e, and also connects the inlet19bwith the outlets19c,19f, and19g. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19dand19eas indicated by an alternate long and short dash line with an arrow inFIG. 34, and also allows the coolant entering the inlet19bto flow out of the outlets19c,19f, and19gas indicated by solid arrows inFIG. 34.

In the first state, the second switching valve20connects the inlets20b, and20cwith the outlet20eand also connects the inlets20a,20d, and20gwith the outlet20f. Thus, the second switching valve20allows the coolant entering the inlets20band20cto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIG. 34, and also allows the coolant entering the inlets20a,20d, and20gto flow out of the outlet20fas indicated by solid arrows inFIG. 30.

FIG. 35shows the operation (second mode) of the cooling system10when the first and second switching valves19and20are switched to a second state.

In the second state, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19c,19e, and19f, thereby closing the outlet19g. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 35, and also allows the coolant entering the inlet19bto flow out of the outlets19c,19e, and19fas indicated by solid arrows inFIG. 35, thereby preventing the coolant from flowing out of the outlet19g.

In the second state, the second switching valve20connects the inlet20bwith the outlet20eand also connects the inlets20a,20c, and20dwith the outlet20f, thereby closing the inlet20g. Thus, the second switching valve20allows the coolant entering the inlets20bto flow out of the outlet20eas indicated by an alternate long and short dash line with an arrow inFIG. 35, and also allows the coolant entering the inlets20a,20c, and20dto flow out of the outlet20fas indicated by solid arrows inFIG. 35, thereby preventing the coolant from flowing out of the inlet20g.

When the battery is charged with the power supplied from the external power supply at a very low temperature of the outside air (for example, at 0° C.) in winter, the controller40performs the first mode shown inFIG. 34.

In the first mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the first state shown inFIG. 34to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlets19dand19eand also connects the inlet19bwith the outlets19c,19f, and19g. The second switching valve20connects the inlets20band20cwith the outlet20e, and also connects the inlets20a,20d, and20gwith the outlet20f.

Accordingly, a first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the battery cooler15, the condenser50, and the heater core51, whereas a second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, the inverter cooler16, and the radiator13.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 34, the coolant discharged from the first pump11is branched into the battery cooler15and the condenser50by the first switching valve19to flow in parallel through the battery cooler15and the condenser50. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51and through the battery cooler15are collected by the second switching valve20to be sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 34, the coolant discharged from the second pump12is branched into the coolant cooler14, the inverter cooler16, and the radiator13by the first switching valve19. The coolant flowing through the coolant cooler14flows in series through the cooler core18. The coolants flowing through the cooler core18, through the inverter cooler16, and through the radiator13are collected by the second switching valve20to be sucked into the second pump12.

In the first mode, the low-temperature coolant cooled by the coolant cooler14flows through the inverter cooler16and the cooler core18, which can cool the inverter and the blast air into the vehicle interior by the low-temperature coolant.

In the first mode, the low-temperature coolant cooled by the coolant cooler14flows through the radiator13, allowing the coolant to absorb heat from the outside air in the radiator13. Then, the coolant which has absorbed heat from the outside air in the radiator13exchanges heat with the refrigerant of the refrigeration cycle22in the coolant cooler14to dissipate heat therefrom. Thus, in the coolant cooler14, the refrigerant of the refrigeration cycle22absorbs heat from the outside air via the coolant.

The refrigerant which has absorbed heat from the outside air in the coolant cooler14exchanges heat with the coolant of the intermediate-temperature coolant circuit in the condenser50, whereby the coolant of the intermediate-temperature coolant circuit is heated. The coolant of the intermediate-temperature circuit heated by the condenser50exchanges heat with the blast air having passed through the cooler core18in flowing through the heater core51, thereby dissipating heat therefrom. Thus, the heater core51heats the blast air having passed through the cooler core18. Accordingly, the fourth mode can achieve heat pump heating that heats the vehicle interior by absorbing heat from the outside air.

The blast air heated by the heater core51is a dried cool air cooled and dehumidified by the cooler core18. Thus, in the first mode, the dehumidification heating can be performed.

For example, when the battery is charged before a passenger rides on a vehicle, pre-air conditioning can be carried out to perform air conditioning of the vehicle interior before the passenger rides on.

Further, in the first mode, the intermediate-temperature coolant heated by the condenser50flows through the battery cooler15, so that the warm energy can be stored in the battery by heating the battery. In this embodiment, in the first mode, the battery is heated up to about 40° C.

When the charging of the battery with the power from the external power source is completed and the vehicle starts traveling, the controller40performs the second mode shown inFIG. 35.

In the second mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the second state shown inFIG. 35to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19c,19e, and19f, thereby closing the outlet19g. The second switching valve20connects the inlet20bwith the outlet20e, and also connects the inlets20a,20c, and20dwith the outlet20f, thereby closing the inlet20g.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the condenser50, and the heater core51, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, the battery cooler15, and the inverter cooler16, thus stopping circulation of the coolant toward the radiator13.

That is, as indicated by an alternate long and short dash line with an arrow inFIG. 35, the coolant discharged from the first pump11flows through the condenser50and the heater core51in series via the first switching valve19, and is then sucked into the first pump11via the second switching valve20.

On the other hand, as indicated by solid arrows inFIG. 35, the coolant discharged from the second pump12is branched into the coolant cooler14, the battery cooler15, and the inverter cooler16by the first switching valve19. The coolant flowing through the coolant cooler14flows in series through the cooler core18. The coolants flowing through the cooler core18, through the battery cooler15, and through the inverter cooler16are collected by the second switching valve20to be sucked into the second pump12.

In the second mode, the low-temperature coolant cooled by the coolant cooler14flows through the battery cooler15, allowing the low-temperature coolant to absorb heat from the battery in the battery cooler15. Then, the coolant absorbing heat from the battery in the battery cooler15exchanges heat with the refrigerant of the refrigeration cycle22in the coolant cooler14to dissipate heat therefrom. Thus, in the coolant cooler14, the refrigerant of the refrigeration cycle22absorbs heat from the battery via the coolant.

The refrigerant absorbing heat from the battery in the coolant cooler14exchanges heat with the coolant of the intermediate-temperature coolant circuit in the condenser50, thereby heating the coolant of the intermediate-temperature coolant circuit. The coolant of the intermediate-temperature circuit heated by the condenser50exchanges heat with the blast air having passed through the cooler core18in flowing through the heater core5, thereby dissipating heat therefrom. Thus, the heater core51heats the blast air having passed through the cooler core18. Accordingly, the second mode can achieve heat pump heating that heats the vehicle interior by absorbing heat from the battery.

The blast air heated by the heater core51is a dried cool air cooled and dehumidified by the cooler core18. Thus, in the second mode, the dehumidification heating can be performed.

In this embodiment, in the first mode, the battery is heated up to about 40° C., and hence in the second mode, the heat pump can be achieved by drawing heat from the battery at the 40° C. Thus, this embodiment can operate the thermal management system at a higher temperature than the case where the low-pressure refrigerant of the refrigeration cycle22absorbs heat from the outside air (for example, 0° C.), thereby improving the operating efficiency of the heat pump.

In the second mode, the coolant does not circulate through the radiator13, and the radiator13does not absorb heat from outside air, which can prevent the frost formation of the radiator13.

Sixth Embodiment

Although in the above respective embodiments, the temperature adjustment devices include the coolant cooler14, the battery cooler15, the inverter cooler16, the exhaust gas cooler17, the cooler core18, the condenser50, and the intake air cooler65by way of example, in a sixth embodiment, as shown inFIG. 36, the temperature adjustment devices include the intake air cooler65, a fuel cooler66, and a vehicle-mounted electronic device cooler67.

The fuel cooler66is a heat exchanger for cooling fuel by exchanging heat between the fuel supplied to the engine and the coolant. The vehicle-mounted electronic device cooler67is a heat exchanger for cooling a vehicle-mounted electronic device by exchanging heat between the vehicle-mounted electronic device and the coolant. Thus, various devices can be used as the temperature adjustment devices.

Like this embodiment, the condenser50may be connected to the discharge side of the first pump11and the inlet19aof the first switching valve19.

Seventh Embodiment

Although in the above third embodiment, the outlet61gand inlet61nfor the coolant are formed in parts constituting the coolant cooler14and the supercooler60of the tank portion61cof the heat exchanger61, in a seventh embodiment, as shown inFIG. 37, the outlet61gand inlet61nfor the coolant are removed, and a hole61pfor allowing the refrigerant to flow therethrough is formed in a part of the partition portion61dthat partitions the internal space of the tank portion61binto a tank space for the coolant cooler14, and another tank space for the supercooler60.

Thus, in the coolant cooler14, the coolant flows from the inlet61einto the tank portion61b, and is then distributed to the tubes for the coolant by the tank portion61b. The coolants after having passed through the tubes for the coolant are collected into the tank portion61cto flow from the hole61pof the partition portion61dinto the supercooler60.

In the supercooler60, the coolant flows into the tank portion61bthrough the hole61pof the partition portion61d, and is then distributed to the tubes for the coolant by the tank portion61c. The coolants after having passed through the tubes for the coolant are collected into the tank portion61bto flow from the outlet61m.

This embodiment can remove the outlet61gand inlet61nfor the coolant with respect to the heat exchanger61of the third embodiment, and thus can simplify the connection structure of the coolant pipes.

Eighth Embodiment

Although in the seventh embodiment, the coolant cooler14, the condenser50, and the supercooler60are included in one heat exchanger61, in an eighth embodiment, as shown inFIG. 38, the coolant cooler14, the condenser50, and the expansion valve25are integrated together.

The coolant cooler14is composed of the tank-and-tube type heat exchanger, and includes a heat exchanger core14a, and tank portions14band14c. The heat exchanger core14aincludes a plurality of tubes through which the coolant and the refrigerant independently flow. The tubes are stacked on each other in parallel. The tank portions14band14care disposed on both sides of the tubes to distribute and collect the coolant and refrigerant for the tubes.

Members constituting the heat exchanger core14a, and the tank portions14band14care formed of metal (for example, an aluminum alloy), and bonded together by brazing.

The condenser50is composed of the tank-and-tube type heat exchanger, and includes a heat exchanger core50a, and tank portions50band50c. The heat exchanger core50aincludes a plurality of tubes through which the coolant and the refrigerant flow independently. The tubes are stacked on each other in parallel. The tank portions50band50care disposed on both sides of the tubes to distribute and collect the coolant and refrigerant for the tubes.

Members constituting the heat exchanger core50a, and the tank portions50band50care formed of metal (for example, an aluminum alloy), and bonded together by brazing.

The coolant cooler14and the condenser24are disposed in parallel in the stacking direction of tubes (in the horizontal direction ofFIG. 38). Specifically, the expansion valve25is fixed while being sandwiched between the coolant cooler14and the condenser24.

The expansion valve25is a thermal expansion valve whose valve opening is adjusted by a mechanical system such that a degree of superheat of the refrigerant flowing from the coolant cooler14is in a predetermined range. The expansion valve25has a temperature sensing portion25afor sensing the superheat degree of the refrigerant on the outlet side of the coolant cooler14.

One tank portion14cof the coolant cooler14is provided with an inlet14efor the coolant and an outlet14ffor the refrigerant. The outlet14ffor the refrigerant is superimposed over the refrigerant inlet of the temperature sensing portion25aof the expansion valve25.

The other tank portion14bof the coolant cooler14is provided with an outlet14gfor the coolant and an inlet14hfor the refrigerant. The inlet14hfor the refrigerant is superimposed over the refrigerant outlet of the expansion valve25.

Thus, in the coolant cooler14, the coolant flows from the inlet14einto the tank portion14c, and is then distributed to the tubes for the coolant by the tank portion14c. The coolants after having passed through the tubes for the coolant are collected into the tank portion14bto flow from the outlet14g.

In the coolant cooler14, the refrigerant decompressed by the expansion valve25flows from the inlet14hinto the tank portion14b, and is then distributed to the tubes for the refrigerant in the tank portion14b. The refrigerants having passed through the tubes for the refrigerant are collected into the tank portion14cto flow from the outlet14finto the temperature sensing portion25aof the expansion valve25. The temperature sensing portion25aof the expansion valve25is provided with an outlet25bfor the refrigerant.

One tank portion50bof the condenser50is provided with an inlet50efor the coolant and an outlet50ffor the refrigerant. The outlet50bfor the refrigerant is superimposed over the refrigerant inlet of the expansion valve25. The other tank portion50cof the condenser50is provided with an outlet50gfor the coolant and an inlet50hfor the refrigerant.

Thus, in the condenser50, the coolant flows from the inlet50einto the tank portion50b, and is then distributed to the tubes for the coolant by the tank portion50b. The coolants after having passed through the tubes for the coolant are collected into the tank portion50cto flow from the outlet50g.

In the condenser50, the refrigerant flows from the inlet50hinto the tank portion50c, and is then distributed to the tubes for the refrigerant by the tank portion50c. The coolants after having passed through the tubes for the refrigerant are collected into the tank portion50bto flow from the outlet50finto the expansion valve25. The refrigerant flowing from the outlet50finto the expansion valve25is decompressed by the expansion valve25to flow into the coolant cooler14.

This embodiment does not need any refrigerant pipe between the coolant cooler14and the expansion valve25, and between the condenser50and the expansion valve25, and thus can simplify the connection structure between the refrigerant pipes.

Ninth Embodiment

Although in the above first embodiment, the operating mode is switched according to the outside air temperature detected by the outside air sensor42, in a ninth embodiment, the operating mode is switched according to the temperature of the inverter and the temperature of the battery.

The first switching valve19is capable of switching among four types of communication states between the inlets19aand19band the outlets19c,19d,19e, and19f. The second switching valve20is also capable of switching among four types of communication states between the inlets20a,20b,20c, and20dand the outlets20e, and20f.

FIG. 39shows the operation (first mode) of the cooling system10when the first and second switching valves19and20are switched to a first state.

In the first state, the first switching valve19closes the inlet19a, and connects the inlet19bwith the outlet19c,19d,19e, and19f. Thus, the first switching valve19does not allow the coolant to enter the inlet19a, but allows the coolant entering the inlet19bto flow out of the outlets19c,19d,19e, and19fas indicated by solid arrows inFIG. 39.

In the first state, the second switching valve20closes the outlet20e, and connects the inlets20a,20b,20c, and20dwith the outlet20f. Thus, the second switching valve20does not allow the coolant to flow out of the outlet20e, but allows the coolant entering the inlets20a,20b,20c, and20dto flow out of the outlet20fas indicated by solid arrows inFIG. 39.

FIG. 40shows the operation (second mode) of the cooling system10when the first and second switching valves19and20are switched to a second state.

In the second state, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19c,19e, and19f. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 40, and also allows the coolant entering the inlet19bto flow out of the outlets19c,19e, and19fas indicated by solid arrows inFIG. 40.

In the second state, the second switching valve20connects the inlets20a,20c, and20dwith the outlet20f, and also connects the inlet20bwith the outlet20e. Thus, the second switching valve20allows the coolant entering the inlet20bto flow out of the outlet20eas indicated by an alternate long and short dash line with an arrow inFIG. 40, and also allows the coolant entering the inlets20a,20c, and20dto flow out of the outlet20fas indicated by a solid arrow inFIG. 40.

FIG. 41shows the operation (third mode) of the cooling system10when the first and second switching valves19and20are switched to a third state.

In the third state, the first switching valve19connects the inlet19awith the outlets19dand19e, and also connects the inlet19bwith the outlets19c, and19f. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlets19dand19eas indicated by alternate long and short dash lines with arrows inFIG. 41, and also allows the coolant entering the inlet19bto flow out of the outlets19cand19fas indicated by solid arrows inFIG. 41.

In the third state, the second switching valve20connects the inlets20a, and20dwith the outlet20f, and also connects the inlets20band20cwith the outlet20e. Thus, the second switching valve20allows the coolant entering the inlets20band20cto flow out of the outlet20eas indicated by alternate long and short dash lines with arrows inFIG. 41, and also allows the coolant entering the inlets20aand20dto flow out of the outlet20fas indicated by solid lines with an arrow inFIG. 41.

FIG. 42shows the operation (fourth mode) of the cooling system10when the first and second switching valves19and20are switched to a fourth state.

In the fourth state, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19eand19f, thereby closing the outlet19c. Thus, the first switching valve19allows the coolant entering the inlet19ato flow out of the outlet19das indicated by an alternate long and short dash line with an arrow inFIG. 42, and also allows the coolant entering the inlet19bto flow out of the outlets19eand19fas indicated by solid arrows inFIG. 42, thereby preventing the coolant from flowing out of the outlet19c.

In the fourth state, the second switching valve20connects the inlets20cand20dwith the outlet20fand also connects the inlet20bwith the outlet20e, thereby closing the inlet20a. Thus, the second switching valve20allows the coolant entering the inlets20bto flow out of the outlet20eas indicated by an alternate long and short dash line with an arrow inFIG. 42, and also allows the coolant entering the inlets20cand20dto flow out of the outlet20fas indicated by solid arrows inFIG. 42, thereby preventing the coolant from flowing out of the inlet20a.

Next, an electric controller of the cooling system10will be described with reference toFIG. 43. The electric controller of the cooling system10has a structure in which detection signals from an inverter temperature sensor45and a battery temperature sensor46are input to the input side of the controller40, in addition to the above-mentioned structure of the first embodiment.

The inverter temperature sensor45is an inverter temperature detector for detecting the temperature of the inverter. For example, the inverter temperature sensor45may detect the temperature of coolant flowing from the inverter cooler16. The battery temperature sensor46is a battery temperature detector for detecting the temperature of the battery. For example, the battery temperature sensor46may detect the temperature of coolant flowing from the battery cooler15.

A control process executed by the controller40of this embodiment will be described with reference toFIG. 44. The controller40executes a computer program according to a flowchart ofFIG. 44.

First, in S200, it is determined whether an inverter temperature Tinv detected by the inverter temperature sensor45exceeds 60° C.

When the inverter temperature Tinv is determined not to exceed 60° C., the priority of cooling of the inverter is determined not to be high, and the operation proceeds to S210, in which the first mode shown inFIG. 39is performed.

In the first mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the first state shown inFIG. 39, thereby operating the second pump12and the compressor23, and stopping the first pump11.

Thus, the first switching valve19closes the inlet19a, and connects the inlet19bwith the outlets19c,19d,19e, and19f. The second switching valve20connects the inlets20a,20b,20c, and20dwith the outlet20f, and closes the outlet20e.

Thus, the low-temperature coolant circuit is formed of the second pump12, the coolant cooler14, the battery cooler15, the inverter cooler16, the exhaust gas cooler17, and the cooler core18, and the intermediate-temperature coolant circuit is not formed.

That is, as indicated by solid arrows inFIG. 39, the coolant discharged from the second pump12flows through the coolant cooler14, and is branched into the battery cooler15, the inverter cooler16, the exhaust gas cooler17, and the cooler core18by the first switching valve19. Then, the coolants flowing in parallel through the battery cooler15, the inverter cooler16, the exhaust gas cooler17, and the cooler core18are collected into the second switching valve20to be sucked into the second pump12.

In contrast, as indicated by a broken line with an arrow inFIG. 39, the coolant is not discharged from the first pump11, and does not flow through the radiator13.

Thus, in the first mode, the low-temperature coolant cooled by the coolant cooler14flows through the battery cooler15, the inverter cooler16, the exhaust gas cooler17, and the cooler core18. As a result, the battery, the inverter, the exhaust gas, and the blast air into the vehicle interior are cooled by the low-temperature coolant.

When the inverter temperature Tinv is determined to exceed 60° C. in S200, the priority of cooling of the inverter is considered to be high, and then the operation proceeds to S220. In S220, it is determined whether or not the inverter temperature Tinv is less than 70° C.

When the inverter temperature Tinv is determined to be 70° C. or more, the inverter is considered to be at an abnormal high temperature, and the operation proceeds to S230, in which a warning light is lit up. Thus, a passenger can be informed that the inverter is at the abnormal high temperature.

When the inverter temperature Tinv is determined to be less than 70° C., the inverter is considered not to be at an abnormal high temperature, and the operation proceeds to S240, in which the warning light is turned off. Thus, a passenger can be informed that the inverter is not at the abnormal high temperature.

In S250following steps S230and S240, it is determined whether or not the coolant of the intermediate-temperature coolant circuit (intermediate-temperature coolant) circulates through the exhaust gas cooler17. Specifically, whether or not the coolant of the intermediate-temperature coolant circuit (intermediate-temperature coolant) circulates through the exhaust gas cooler17is determined based on the operating states of the first and second switching valves19and20.

When the intermediate-temperature coolant is determined not to circulate through the exhaust gas cooler17, the operation proceeds to S260so as to reduce the cooling capacity of the exhaust gas. In S260, the second mode shown inFIG. 40is performed.

In the second mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the second state shown inFIG. 40to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlet19dand also connects the inlet19bwith the outlets19c,19e, and19f. The second switching valve20connects the inlets20a,20c, and20dwith the outlet20f, and also connects the inlet20bwith the outlet20e.

Accordingly, an intermediate-temperature coolant circuit is formed of the first pump11, the exhaust gas cooler17, and the radiator13, whereas a low-temperature coolant circuit is formed of the second pump12, the coolant cooler14, the battery cooler15, the inverter cooler16, and the cooler core18.

That is, as indicated by an alternate long and short dash line with an arrow inFIG. 40, the coolant discharged from the first pump11flows through the exhaust gas cooler17via the first switching valve19, and then through the radiator13via the second switching valve20, thereby being sucked into the first pump11.

On the other hand, as shown in solid arrows inFIG. 40, the coolant discharged from the second pump12flows through the coolant cooler14to be branched into the battery cooler15, the inverter cooler16, and the cooler core18by the first switching valve19. The coolants flowing in parallel through the battery cooler15, the inverter cooler16, and the cooler core18are collected into the second switching valve20to be sucked into the second pump12.

Thus, in the second mode, the intermediate-temperature coolant cooled by the radiator13flows through the exhaust gas cooler17, whereas the low-temperature coolant cooled by the coolant cooler14flows through the battery cooler15, the inverter cooler16, and the cooler core18. As a result, the exhaust gas is cooled by the intermediate-temperature coolant, and the battery, the inverter, and the blast air into the vehicle interior are cooled by the low-temperature coolant.

Accordingly, the cooling capacity of the inverter can be improved as compared to the first mode in which the exhaust gas can also be cooled by the low-temperature coolant.

When the intermediate-temperature coolant is determined to circulate through the exhaust gas cooler17in S250, the operation proceeds to S270. In S270, it is determined whether a battery temperature Tbatt detected by the battery temperature sensor46exceeds 50° C. or not.

When the battery temperature Tbatt is determined not to exceed 50° C., the priority of cooling of the battery is determined not to be high, and the operation proceeds to S280, in which the third mode shown inFIG. 41is performed.

In the third mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the third state shown inFIG. 41to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlets19d, and19e, and also connects the inlet19bwith the outlets19cand19f. The second switching valve20connects the inlets20a, and20dwith the outlet20f, and also connects the inlets20band20cwith the outlet20e.

Accordingly, an intermediate-temperature coolant circuit is formed of the first pump11, the battery cooler15, the exhaust gas cooler17, and the radiator13, whereas a low-temperature coolant circuit is formed of the second pump12, the coolant cooler14, the inverter cooler16, and the cooler core18.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 41, the coolant discharged from the first pump11is branched by the first switching valve19into the battery cooler15and the exhaust gas cooler17. Then, the coolants flowing in parallel through the battery cooler15and the exhaust gas cooler17are collected into the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

On the other hand, as shown in solid arrows inFIG. 41, the coolant discharged from the second pump12flows through the coolant cooler14to be branched into the inverter cooler16, and the cooler core18by the first switching valve19. The coolants flowing in parallel through the inverter cooler16, and the cooler core18are collected into the second switching valve20to be sucked into the second pump12.

Thus, in the second mode, the intermediate-temperature coolant cooled by the radiator13flows through the battery cooler15and the exhaust gas cooler17, whereas the low-temperature coolant cooled by the coolant cooler14flows through the inverter cooler16, and the cooler core18. As a result, the battery and the exhaust gas are cooled by the intermediate-temperature coolant, and the inverter and the blast air into the vehicle interior are cooled by the low-temperature coolant.

Thus, the cooling capacity of the inverter can be improved as compared to the second mode in which the battery can also be cooled by the low-temperature coolant.

When the battery temperature Tbatt is determined to exceed 50° C. in S270, the priority of cooling of the battery is determined to be high, and the operation proceeds to S290, in which the fourth mode shown inFIG. 42is performed.

In the fourth mode, the controller40controls the electric motor30for a switching valve such that the first and second switching valves19and20are brought into the fourth state shown inFIG. 42to thereby operate the first and second pumps11and12and the compressor23.

Thus, the first switching valve19connects the inlet19awith the outlet19d, and also connects the inlet19bwith the outlets19e, and19f, thereby closing the outlet19c. The second switching valve20closes the inlet20aand connects the inlet20bwith the outlet20e, and also connects the inlets20cand20dwith the outlet20f.

Accordingly, an intermediate-temperature coolant circuit is formed of the first pump11, the exhaust gas cooler17, and the radiator13, whereas a low-temperature coolant circuit is formed of the second pump12, the coolant cooler14, the battery cooler15, and the inverter cooler16.

That is, as indicated by an alternate long and short dash line with an arrow inFIG. 42, the coolant discharged from the first pump11flows through the exhaust gas cooler17via the first switching valve19, and then through the radiator13via the second switching valve20, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 41, the coolant discharged from the second pump12flows through the coolant cooler14, and is branched into the battery cooler15and the inverter cooler16by the first switching valve19. Then, the coolants flowing in parallel through the battery cooler15, and the inverter cooler16are collected into the second switching valve20to be sucked into the second pump12. In contrast, as indicated by a broken line with an arrow inFIG. 41, the coolant does not circulate through the cooler core18.

In this way, in the second mode, the intermediate-temperature coolant cooled by the radiator13flows through the exhaust gas cooler17, whereas the low-temperature coolant cooled by the coolant cooler14flows through the battery cooler15and the inverter cooler16, thereby stopping the circulation of the coolant toward the cooler core18. As a result, the battery and the exhaust gas are cooled by the intermediate-temperature coolant, and the inverter is cooled by the low-temperature coolant, thereby stopping the cooling (that is, air conditioning) of the blast air into the vehicle interior.

Thus, the cooling capabilities of the battery and the inverter can be improved as compared to the second mode in which the blast air into the vehicle interior can also be cooled by the low-temperature coolant.

In this embodiment, when the inverter temperature Tinv is higher than the predetermined temperature (60° C. in this embodiment), the third mode is performed to allow the coolant to circulate between the inverter coolant16and the second pump12, and also to circulate between the above-mentioned battery cooler15and the first pump11. Thus, when the inverter temperature is high, the inverter with a smaller heat capacity can be preferentially cooled as compared to the battery with a larger heat capacity. As a result, the inverter can be effectively cooled while suppressing the increase in temperature of the battery.

Tenth Embodiment

As shown inFIG. 45, a tenth embodiment of the invention includes a coolant tank70for storing the coolant therein, in addition to the structure of the first embodiment.

The coolant tank70is provided with a first coolant outlet/inlet70aand a second coolant outlet/inlet70b. The first coolant outlet/inlet70ais connected to a first branch portion71provided between an outlet20eof the second switching valve20and a coolant inlet side of the radiator13. The second coolant outlet/inlet70bis connected to a second branch portion72provided between an outlet20fof the second switching valve20and a suction side of the second pump12.

Thus, a coolant flow path of the first coolant circuit (coolant circuit on the first pump11side) on the suction side of the first pump11communicates with a coolant flow path of the second coolant circuit (coolant circuit on the second pump12side) on the suction side of the second pump12via the coolant tank70.

In this embodiment, the first coolant circuit communicates with the second coolant circuit, which can equalize the internal pressure between the first and second coolant circuits. Thus, a difference in pressure acting on a valve element inside each of the first and second switching valves19and20can be decreased to thereby prevent the leakage of the coolant in the switching valve.

For example, given that the first coolant circuit and the second coolant circuit communicate with each other on the discharge side of one pump as well as on the suction side of the other pump, the coolant circuit communicating with the suction side of the pump might have its internal pressure abnormally increased. In contrast, in this embodiment, the first coolant circuit and the second coolant circuit communicate with each other on the suction sides of both pumps, which can prevent the internal pressure of the coolant circuits from abnormally increasing, thereby facilitating the design of parts with good pressure resistance.

Eleventh Embodiment

Although in the tenth embodiment, the first coolant circuit and the second coolant circuit communicate with each other on the suction sides of both the pumps, in an eleventh embodiment of the invention, as shown inFIG. 46, the first coolant circuit and the second coolant circuit communicate with each other on the discharge sides of both the pumps.

Specifically, the first branch portion71of the first coolant circuit is provided between the discharge side of the first pump11and the inlet19aof the first switching valve19, and the second branch portion72of the second coolant circuit is provided between the discharge side of the second pump12and the inlet19bof the first switching valve19.

Although in the tenth embodiment, the coolant tank70is provided with the first coolant outlet/inlet70afor connection with the first coolant circuit, and the second coolant outlet/inlet70bfor connection with the second coolant circuit, in an eleventh embodiment, the coolant tank70is provided with one coolant outlet/inlet70cconnected to both the first and second coolant circuits.

One coolant pipe connected to the coolant outlet/inlet70cof the coolant tank70is branched into two parts toward the first branch portion71and the second branch portion72.

This embodiment can also obtain the same operation and effects as those of the tenth embodiment described above.

Twelfth Embodiment

A twelfth embodiment of the invention includes a circulation flow path80, a third pump81, a three-way valve82, and an inlet water temperature sensor83as shown inFIG. 47, in addition to the structure of the second embodiment.

The circulation flow path80is a flow path through which the coolant circulates without passing through the first and second switching valves19and20. The circulation flow path80has one end connected to the coolant outlet side of the battery cooler15, and the other end connected to the coolant inlet side of the battery cooler15.

The circulation flow path80is provided in parallel to a flow path84for the battery cooler (non-circulation flow path). The flow path84for the battery cooler is a flow path in which the battery cooler15is disposed. The flow path84has one end connected to the outlet19eof the first switching valve19, and the other end connected to the inlet20cof the second switching valve20.

In the example shown inFIG. 47, parts of the circulation flow path80and the flow path84for the battery cooler, which are located near the battery cooler15, are integrated together to form one flow path. Thus, between the battery cooler15and the second switching valve20, the flow path is branched into the circulation flow path80and the flow path84for the battery cooler, whereas between the battery cooler15and the first switching valve19, the circulation flow path80and the flow path84for the battery cooler are merged into.

The third pump81is an electric pump adapted for drawing and discharging a coolant (heat medium), and disposed in the circulation flow path80. In the example ofFIG. 47, the third pump81is disposed in a branched part of the circulation flow path80other than the flow path84for the battery cooler (or, a part forming a flow path different from the flow path84for the battery cooler).

The three-way valve82is a circulation switching valve for switching between opening and closing of the circulation flow path80and the flow path84for the battery cooler, and thus is disposed in the branch portion between the circulation flow path80and the flow path84for the battery cooler.

When the three-way valve82opens the circulation flow path80and closes the flow path84for the battery cooler, the coolant flowing from the battery cooler15circulates through the circulation flow path80into the battery cooler15. In contrast, when the three-way valve82opens the flow path84for the battery cooler and closes the circulation flow path80, the coolant flowing from the battery cooler15flows through the flow path84for the battery cooler to flow into the second switching valve20.

The inlet water temperature sensor83is disposed on the coolant inlet side of the battery cooler15. The inlet water temperature sensor83is an inflow temperature detector for detecting the temperature of coolant flowing into the battery cooler15(inflow heat medium temperature).

The operations of the third pump81and the three-way valve82are controlled by the controller40. A detection signal from the inlet water temperature sensor83is input to the controller40.

A control process executed by the controller40of this embodiment will be described with reference toFIG. 48. The controller40executes a computer program according to a flowchart ofFIG. 48.

In S300, first, it is determined whether the battery is required to be cooled or not. Specifically, when the battery temperature is equal to or higher than a first predetermined temperature (for example, 35° C.), the cooling of the battery is considered to be required. In contrast, when the battery temperature is lower than the first predetermined temperature, the cooling of the battery is determined not to be required.

When the cooling of the battery is determined to be required, the operation proceeds to S310, in which it is determined whether the battery temperature exceeds a target cooling temperature (for example, 40° C.). When the battery temperature is determined to exceed the target cooling temperature, the operation proceeds to S320. When the battery temperature is determined not to exceed the target cooling temperature, the operation returns to S300.

In S320, the operations of the first switching valve19, the second switching valve20, the three-way valve82, and the third pump81are controlled so as to achieve a first cooling mode (non-circulation mode) shown inFIG. 49.

In the first cooling mode, the first switching valve19connects the inlet19awith the outlet19d, as well as the inlet19bwith the outlets19c,19e, and19f, whereas the second switching valve20connects the inlet20bwith the outlet20e, as well as the inlets20a,20c, and20dwith the outlet20f.

In the first cooling mode, the three-way valve82opens the flow path84for the battery cooler to close the circulation flow path80, so that the third pump81is stopped.

Thus, a first coolant circuit (intermediate-temperature coolant circuit) indicated by an alternate long and short dash line with an arrow inFIG. 49and a second coolant circuit (low-temperature coolant circuit) indicated by a solid arrow inFIG. 49are formed.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the condenser50, the heater core51, and the radiator13, whereas the second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, the battery cooler15, and the inverter cooler16.

That is, as indicated by the alternate long and short dash line with the arrow inFIG. 49, the coolant discharged from the first pump11flows through the condenser50and heater core51in series via the first switching valve19, and then through the second switching valve20and radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by the solid line with the arrow inFIG. 49, the coolant discharged from the second pump12is branched into the coolant cooler14, the battery cooler15, and the inverter cooler16by the first switching valve19. The coolants flow in parallel through the coolant cooler14, the battery cooler15, and the inverter cooler16. The coolant flowing through the coolant cooler14flows in series through the cooler core18. The coolant flowing through the cooler core18, the coolant flowing through the battery cooler15, and the coolant flowing through the inverter cooler16are collected by the second switching valve20to be sucked into the second pump12.

As mentioned above, in the first cooling mode, the low-temperature coolant cooled by the coolant cooler14flows through the battery cooler15. Thus, the battery is cooled by the low-temperature coolant cooled by the coolant cooler14.

In the following S330, it is determined whether or not the coolant temperature detected by the inlet water temperature sensor83(hereinafter referred to as a “battery-cooler inlet water temperature”) is below a first cooling determination temperature Tc1(for example, 10° C.). The first cooling determination temperature Tc1is a temperature determined based on the lower limit temperature in a range of usable temperatures of the battery (for example, from 10 to 40° C.), and is previously stored in the controller40.

When the battery-cooler inlet water temperature is determined to be less than the first cooling determination temperature Tc1, the operation proceeds to S340. When the battery-cooler inlet water temperature is determined not to be less than the first cooling determination temperature Tc1, the operation returns to S310.

In S340, the operations of the first switching valve19, the second switching valve20, the three-way valve82, and the third pump81are controlled so as to achieve a second cooling mode (circulation mode) shown inFIG. 50.

In the second cooling mode, the first switching valve19connects the inlet19awith the outlet19d, as well as the inlet19bwith the outlets19cand19f, and closes the outlet19e, whereas the second switching valve20connects the inlet20bwith the outlet20e, as well as the inlets20aand20dwith the outlet20f, and closes the inlet20c.

In the second cooling mode, the three-way valve82opens the circulation flow path80to close the flow path84for the battery cooler, so that the third pump81operates.

Thus, a first coolant circuit (intermediate-temperature coolant circuit) indicated by a solid arrow inFIG. 50, a second coolant circuit (low-temperature coolant circuit) indicated by an alternate long and two short dashes line with an arrow inFIG. 50, and an internal circulation circuit indicated by an alternate long and two short dashes line with an arrow inFIG. 50are formed.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the first pump11, the condenser50, the heater core51, and the radiator13. The second coolant circuit (low-temperature coolant circuit) is formed of the second pump12, the coolant cooler14, the cooler core18, the inverter cooler16. An internal circulation circuit is formed of the third pump81and the battery cooler15.

That is, as indicated by the alternate long and short dash line with the arrow inFIG. 50, the coolant discharged from the first pump11flows through the condenser50and heater core51in series via the first switching valve19, and then through the second switching valve20and the radiator13, thereby being sucked into the first pump11.

On the other hand, as indicated by solid arrows inFIG. 50, the coolant discharged from the second pump12is branched into the coolant cooler14and the inverter cooler16by the first switching valve19to flow in parallel through the coolant cooler14and the inverter cooler16. The coolant flowing through the coolant cooler14flows in series through the cooler core18. The coolants flowing through the cooler core18and through the inverter cooler16are collected by the second switching valve20to be sucked into the second pump12.

Further, as indicated by an alternate long and two short dashes line with an arrow inFIG. 50, the coolant discharged from the third pump81flows through the battery cooler15to be sucked into the third pump81.

As mentioned above, in the second cooling mode, the coolant circulating through the internal circulation circuit flows through the battery cooler15. Thus, the low-temperature coolant cooled by the coolant cooler14does not flow through the battery cooler15.

In the following S350, it is determined whether or not the battery-cooler inlet water temperature exceeds a second cooling determination temperature Tc2(for example, 12° C.). The second cooling determination temperature Tc2is a higher temperature than the first cooling determination temperature Tc1, and is previously stored in the controller40.

When the battery-cooler inlet water temperature is determined to exceed the second cooling determination temperature Tc2, the operation returns to S310. When the battery-cooler inlet water temperature is determined not to exceed the second cooling determination temperature Tc2, the operation returns to S350.

On the other hand, when the cooling of the battery is determined not to be required in S300, the operation proceeds to S360, in which it is determined whether the battery is required to be heated or not. Specifically, when the battery temperature is less than a second predetermined temperature (for example, 15° C.), the heating of the battery is considered to be required. In contrast, when the battery temperature is equal to or higher than the second predetermined temperature, the heating of the battery is determined not to be required.

When the heating of the battery is determined to be required, the operation proceeds to S370, in which it is determined whether the battery temperature is below a target heating temperature (for example, 10° C.). When the battery temperature is determined to be lower than the target heating temperature, the operation proceeds to S380. When the battery temperature is determined not to be lower than the target heating temperature, the operation returns to S300.

In S380, the operations of the first switching valve19, the second switching valve20, the three-way valve82, and the third pump81are controlled so as to achieve a first heating mode (non-circulation mode) shown inFIG. 51.

In the first heating mode, the first switching valve19connects the inlet19awith the outlet19c, as well as the inlet19bwith the outlets19dand19e, whereas the second switching valve20connects the inlet20awith the outlet20e, as well as the inlets20band20cwith the outlet20f.

In the first heating mode, the three-way valve82opens the flow path84for the battery cooler to close the circulation flow path80, so that the third pump81is stopped.

Thus, a first coolant circuit (intermediate-temperature coolant circuit) indicated by an alternate long and short dash line with an arrow inFIG. 51and a second coolant circuit (low-temperature coolant circuit) indicated by a solid arrow inFIG. 51are formed.

Accordingly, a first coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the battery cooler15, the condenser50, and the heater core51, whereas a second coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, the cooler core18, and the radiator13.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 51, the coolant discharged from the second pump12is branched into the battery cooler15and the condenser50by the first switching valve19to flow in parallel through the battery cooler15and the condenser50. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the battery cooler15and through the heater core51are collected by the second switching valve20to be sucked into the second pump12.

On the other hand, as indicated by a solid arrow inFIG. 51, the coolant discharged from the first pump11flows through the coolant cooler14and the cooler core18in series via the first switching valve19, and is then sucked into the first pump11via the second switching valve20and the radiator13.

As mentioned above, in the first heating mode, the intermediate-temperature coolant heated by the condenser50flows through the battery cooler15. Thus, the battery is heated by the intermediate-temperature coolant heated by the condenser50.

In the following S390, it is determined whether or not the battery-cooler inlet water temperature exceeds a first heating determination temperature Tw1(for example, 40° C.). The first heating determination temperature Tw1is a temperature determined based on the upper limit temperature in a range of usable temperatures of the battery (for example, from 10 to 40° C.), and is previously stored in the controller40.

When the battery-cooler inlet water temperature is determined to exceed the first heating determination temperature Tw1, the operation proceeds to S400.

When the battery-cooler inlet water temperature is determined not to exceed the first heating determination temperature Tw1, the operation returns to S370.

In S400, the operations of the first switching valve19, the second switching valve20, the three-way valve82, and the third pump81are controlled so as to achieve a second heating mode (circulation mode) shown inFIG. 52.

In the second heating mode, the first switching valve19connects the inlet19awith the outlet19c, as well as the inlet19bwith the outlet19d, and closes the outlet19e, whereas the second switching valve20connects the inlet20awith the outlet20e, as well as the inlet20bwith the outlet20f, and closes the inlet20c.

In the second heating mode, the three-way valve82opens the circulation flow path80to close the flow path84for the battery cooler, so that the third pump81is operated.

Thus, a first coolant circuit (intermediate-temperature coolant circuit) indicated by an alternate long and short dash line with an arrow inFIG. 52, a second coolant circuit (low-temperature coolant circuit) indicated by a solid arrow inFIG. 52, and an internal circulation circuit indicated by an alternate long and two short dashes line with an arrow inFIG. 52are formed.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the condenser50, and the heater core51, whereas a second coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, the cooler core18, and the radiator13.

That is, as indicated by the alternate long and short dash line with the arrow inFIG. 52, the coolant discharged from the second pump12flows through the condenser50and the heater core51in series via the first switching valve19, and is then sucked into the second pump12via the second switching valve20.

On the other hand, as indicated by the solid line with the arrow inFIG. 52, the coolant discharged from the first pump11flows through the coolant cooler14and the cooler core18in series via the first switching valve19, and is then sucked into the first pump11via the second switching valve20.

Further, as indicated by an alternate long and two short dashes line with an arrow inFIG. 52, the coolant discharged from the third pump81flows through the battery cooler15to be sucked into the third pump81.

As mentioned above, in the second heating mode, the coolant circulating through the internal circulation circuit flows through the battery cooler15. Thus, the intermediate-temperature coolant heated by the condenser50does not flow through the battery cooler15.

In the following S410, it is determined whether or not the battery-cooler inlet water temperature is below the second heating determination temperature Tw2(for example, 38° C.). The second heating determination temperature Tw2is higher than the first heating determination temperature Tw1, and is previously stored in the controller40.

When the battery-cooler inlet water temperature is determined to be lower than the second heating determination temperature Tw2, the operation returns to S370. When the battery-cooler inlet water temperature is determined not to be lower than the first cooling determination temperature Tc1, the operation returns to S410.

On the other hand, when the heating of the battery is determined not to be required in S360, the operation proceeds to S420. In S420, it is determined whether or not a difference in temperature between battery cells forming the battery, namely, a difference in temperature between a cell having the highest temperature and another cell having the lowest temperature exceeds a predetermined value (for example, 5° C.).

When the difference in temperature between the battery cells is determined to exceed the predetermined value, the operation proceeds to S430, in which the operations of the first switching valve19, the second switching valve20, the three-way valve82, and the third pump81are controlled so as to achieve a battery temperature equalization operating mode (circulation mode) shown inFIG. 53.

In the battery temperature equalization operating mode, the first switching valve19closes the outlet19e, and the second switching valve20closes the inlet20c. In the battery temperature equalization operating mode, the three-way valve82opens the circulation flow path80to close the flow path84for the battery cooler, so that the third pump81is operated.

Thus, the internal circulation circuit indicated by an alternate long and two short dashes line with an arrow inFIG. 53is configured. Accordingly, as indicated by the alternate long and two short dashes line with the arrow inFIG. 53, the coolant discharged from the third pump81flows through the battery cooler15to be sucked into the third pump81.

As mentioned above, in the battery temperature equalization operating mode, the coolant circulating through the internal circulation circuit flows through the battery cooler15. Thus, the low-temperature coolant cooled by the coolant cooler14and the intermediate-temperature coolant heated by the condenser50do not flow through the battery cooler15.

When the difference in temperature between the battery cells is determined not to exceed the predetermined value in S420, the operation returns to S300.

In this embodiment, when the cooling of the battery is required, once the battery-cooler inlet water temperature becomes lower than the first cooling determination temperature Tc1, the first cooling mode is switched to the second cooling mode, which can optimize the operation of the battery, while ensuring the cooling performance. In the following, the reason for this will be described.

The temperature of coolant flowing into the battery coolant15is preferably in a range of 10 to 40° C. This is because the temperature at which the battery optimally operates ranges from 10 to 40° C. That is, when the battery temperature exceeds 40° C., the degradation of the battery is rapidly promoted, which leads to the reduction in lifetime of the battery, or breakage of the battery. On the other hand, when the battery temperature is lower than 10° C., the chemical reaction of the battery is suppressed to reduce an input/output of the battery, which reduces the acceleration of the vehicle, or the efficiency of regeneration and charging of the battery.

Since the output or internal resistance of the battery depends on the temperature, the drastic change in temperature of the battery causes drastic changes in input and output performance of the battery, which makes the controllability of the battery worse. Further, the drastic change in temperature of the battery also causes variations in temperature of the inside of the battery, which reduces the lifetime of the battery.

In contrast, when the cooling performance is intended to be ensured, the temperature of coolant flowing into the cooler core18is preferably in a range of 0 to 10° C.

Thus, the battery cooler15and the cooler core18differ in appropriate temperature range for the coolant flowing thereinto.

In this aspect, in the second cooling mode, the coolant circulating through the internal circulation circuit flows through the battery cooler15, and the low-temperature coolant cooled by the coolant cooler14does not flow through the battery cooler15, so that the coolant circulating through the internal circulation circuit is heated by the heat from the battery, resulting in a gradual increase in temperature of the coolant.

Even though the temperature of the low-temperature coolant cooled by the coolant cooler14is lower than the first cooling determination temperature Tc1, the temperature of coolant flowing through the battery cooler15can be equal to or higher than the first cooling determination temperature Tc1. This embodiment can prevent the degradation of the input and output of the battery due to the battery temperature lower than the usable temperature range, as well as the reduction in charging efficiency of the battery.

On the other hand, the low-temperature coolant cooled by the coolant cooler14flows into the cooler core18. The low-temperature coolant having a temperature equal to or lower than the first cooling determination temperature Tc1can flow into the cooler core18to ensure the cooling performance.

Furthermore, when the temperature of coolant circulating through the internal circulation circuit gradually increases in the second cooling mode to exceed the second cooling determination temperature Tc2, the second cooling mode is switched to the first cooling mode, whereby the low-temperature coolant cooled by the coolant cooler14is guided to the battery cooler15. Thus, the temperature of the coolant flowing through the battery cooler15can be prevented from continuously increasing to be much higher than the second cooling determination temperature Tc2.

Likewise, in order to ensure the heating performance, the temperature of coolant flowing into the heater51is preferably in a range of 50 to 60° C. The battery cooler15and the heater core51differ in appropriate temperature range of the coolant flowing thereinto.

In this embodiment, taking this point into consideration, when the cooling of the battery is required, once the battery-cooler inlet water temperature exceeds the first heating determination temperature Tw1, the first cooling mode is switched to the second cooling mode, which can optimize the operation of the battery, while ensuring the heating performance.

That is, in the second heating mode, the coolant circulating through the internal circulation circuit flows through the battery cooler15, and the intermediate-temperature coolant heated by the condenser50does not flow through the battery cooler15, so that the coolant circulating through the internal circulation circuit is cooled by the battery, resulting in a gradual decrease in temperature of the coolant.

Even though the temperature of the intermediate-temperature coolant heated by the condenser50exceeds the first heating determination temperature Tw1, the temperature of coolant flowing through the battery cooler15can be equal to or higher than the first heating determination temperature Tw1. This embodiment can prevent the quick degradation of the battery and the decrease in lifetime of the battery due to the battery temperature exceeding the usable temperature range, as well as the breakage of the battery.

On the other hand, the intermediate-temperature coolant heated by the condenser50flows into the heater core51. The intermediate-temperature coolant having a temperature equal to or lower than the first heating determination temperature Tw1can flow into the heater core51to ensure the heating performance.

Once the temperature of the coolant circulating through the internal circulation circuit gradually decreases in the second heating mode to be lower than the second heating determination temperature Tw2, the second heating mode is switched to the first heating mode, whereby the intermediate-temperature coolant heated by the condenser50is guided to the battery cooler15. Thus, the temperature of the coolant flowing through the battery cooler15can be prevented from continuously decreasing to be much lower than the second heating determination temperature Tw2.

In the case where neither the cooling nor heating of the battery is required in this embodiment, when the difference in temperature between the battery cells forming the battery exceeds the predetermined value (for example, 5° C.), the battery temperature equalization operating mode is performed, so that the coolant can circulate through the battery cooler15to decrease the difference in temperature between the battery cells forming the battery. In the following, the reason for this will be described.

In general, a battery is mounted under a floor or a luggage area of a vehicle. In particular, in battery cars or the like, batteries are mounted to be distributed due to a large volume of each battery, which makes the temperature distribution in the surroundings of the respective battery cells, resulting in variations in temperature of each battery cell.

Such a difference in temperature between the battery cells causes variations in internal resistance of the respective cells, leading to variations in amount of heat generated by each cell, output from the cell, degradation speed thereof, and the like, disadvantageously resulting in reduction in output from a battery pack and in lifetime thereof.

From this point of view, even when neither the cooling nor heating of the battery is required in this embodiment, once the difference in temperature between the battery cells exceeds the predetermined value (for example, 5° C.), the battery temperature equalization operating mode is performed to allow the coolant to flow through the battery cooler15, so that the difference in temperature among the battery cells can be reduced.

In the battery temperature equalization operating mode, the coolant circulating through the internal circulation circuit flows through the battery cooler15, and the low-temperature coolant cooled by the coolant cooler14and the intermediate-temperature coolant heated by the condenser50do not flow through the battery cooler15.

Thus, when the air conditioning is not necessary, that is, when the coolant does not need to be cooled by the coolant cooler14and also does not need to be heated by the condenser50, the coolant is allowed to circulate through the battery cooler15.

When the air conditioning is not necessary, the coolant can circulate through the battery cooler15without allowing the coolant to circulate through the first and second coolant circuits, which can reduce a water flow resistance as compared to the case where the coolant of the first or second coolant circuit circulates through the battery cooler15, further decreasing the power consumption by the pump.

Thirteenth Embodiment

Although in the twelfth embodiment, the circulation flow path80is provided for the battery cooler15, in a thirteenth embodiment, as shown inFIG. 54, the circulation flow path80is provided for the cooler core18.

The circulation flow path80is provided in parallel with a flow path85for a cooler core. The flow path85for the cooler core is a flow path in which the cooler core18is disposed. The flow path85has one end connected to the outlet19cof the first switching valve19, and the other end connected to the inlet20aof the second switching valve20.

One end of the circulation flow path80is connected to the coolant outlet side of the cooler core18, and the other end of the circulation flow path80is connected to the coolant inlet side of the cooler core18.

In the example shown inFIG. 54, parts of the circulation flow path80and the flow path85for the cooler core, which are located near the cooler core18, are integrated together to form one flow path. Thus, between the cooler core18and the second switching valve20, the flow path is branched into the circulation flow path80and the flow path85for the cooler core, whereas between the cooler core18and the first switching valve19, the circulation flow path80and the flow path85for the cooler core are merged into one path.

The three-way valve82is disposed in the branch portion between the circulation flow path80and the flow path85for the cooler core, and adapted to switch between opening and closing of the circulation flow path80and the flow path85for the cooler core.

That is, when the three-way valve82opens the circulation flow path80and closes the flow path85for the cooler core, the coolant flowing from the cooler core18circulates through the circulation flow path80into the cooler core18. In contrast, when the three-way valve82opens the flow path85for the cooler core and closes the circulation flow path80, the coolant flowing from the cooler core18circulates through the cooler core18to flow into the second switching valve20.

The inlet water temperature sensor83is disposed on the coolant inlet side of the cooler core18. The inlet water temperature sensor83is adapted to detect the temperature of coolant flowing into the cooler core18(intake heat medium temperature).

Although in the above twelfth embodiment, the coolant cooler14and the cooler core18are disposed in series in the same flow path, in this embodiment, the coolant cooler14and the cooler core18are disposed in different flow paths in parallel.

That is, the coolant inlet side of the coolant cooler14is connected to the outlet19gof the first switching valve19. The coolant outlet side of the coolant cooler14is connected to the inlet20gof the second switching valve20.

The first switching valve19is capable of switching the communication states between the inlets19aand19band the outlets19c,19d,19e,19f, and19g. The second switching valve20is also capable of switching the communication states between the inlets20a,20b,20c,20d, and20gand the outlets20e, and20f.

Although a description has been omitted in the embodiments mentioned above, as shown inFIG. 54, an air mix door86is disposed between the cooler core18and the heater core51within the casing27of the indoor air conditioning unit. The air mix door86is a temperature adjustment device for controlling the temperature of conditioned air to be blown into the vehicle interior by adjusting the ratio of the volume of air passing through the heater core51to that of air bypassing the heater core51in the blast air having passed through the cooler core18.

A control process executed by the controller40of this embodiment will be described with reference toFIG. 55. The controller40executes a computer program according to a flowchart ofFIG. 55.

In S500, first, it is determined whether the cooling is required or not. Specifically, when the air conditioning switch44is turned on, the cooling is determined to be required. In contrast, when the air conditioning switch44is turned off, the cooling is determined not to be required.

When the cooling is determined to be required, the operation proceeds to S510. In S510, the operations of the first and second switching valves19and20, the three-way valve82, and the third pump81are controlled so as to achieve the first cooling mode (non-circulation mode) shown inFIG. 56.

In the first cooling mode, the first switching valve19connects the inlet19awith the outlets19cand19g, as well as the inlet19bwith the outlets19dand19e, whereas the second switching valve20connects the inlets20aand20gwith the outlet20e, as well as the inlets20band20cwith the outlet20f.

In the first cooling mode, the three-way valve82opens the flow path85for the cooler core to close the circulation flow path80, so that the third pump81is stopped.

Thus, a first coolant circuit (intermediate-temperature coolant circuit) indicated by an alternate long and short dash line with an arrow inFIG. 56, and a second coolant circuit (low-temperature coolant circuit) indicated by a solid arrow inFIG. 56are formed.

Accordingly, a first coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the condenser50, the heater core51, and the battery cooler15, whereas a second coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, the cooler core18, and the radiator13.

That is, as indicated by alternate long and short dash lines with arrows inFIG. 56, the coolant discharged from the second pump12is branched into the condenser50and the battery cooler15by the first switching valve19. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51and through the battery cooler15are collected by the second switching valve20to be sucked into the second pump12.

On the other hand, as indicated by solid arrows inFIG. 56, the coolant discharged from the first pump11is branched into the coolant cooler14and the cooler core18by the first switching valve19to flow through the coolant cooler14and the cooler core18in parallel. The coolants flowing through the coolant cooler14, and through the cooler core18are collected by the second switching valve20to flow through the radiator13, thereby being sucked into the first pump11.

As mentioned above, in the first cooling mode, the low-temperature coolant cooled by the coolant cooler14flows through the cooler core18. Thus, the blast air into the vehicle interior is cooled by the low-temperature coolant cooled by the coolant cooler14.

In the following S520, it is determined whether or not the coolant temperature detected by the inlet water temperature sensor83(hereinafter referred to as a “cooler core inlet water temperature”) is lower than a first cooling determination temperature Tf1(for example, 1° C.). The first cooling determination temperature Tf1is a temperature determined based on the lower limit temperature in a range of temperatures that does not cause the frost formation (frost) on the surface of the cooler core18, and is previously stored in the controller40. Instead of the cooler core inlet water temperature, the surface temperature (fin temperature) of the cooler core18may be used.

When the cooler core inlet water temperature is determined to be lower than the first cooling determination temperature Tf1, the operation proceeds to S530. When the cooler core inlet water temperature is determined not to be lower than the first cooling determination temperature Tf1, the operation returns to S500.

In S530, the operations of the first switching valve19, the second switching valve20, the three-way valve82, and the third pump81are controlled so as to achieve a second cooling mode (circulation mode) shown inFIG. 57.

In the second cooling mode, the first switching valve19connects the inlet19awith the outlet19g, as well as the inlet19bwith the outlets19dand19e, and closes the outlet19c, whereas the second switching valve20connects the inlet20gwith the outlet20e, as well as the inlets20band20cwith the outlet20f, and closes the inlet20a.

In the second cooling mode, the three-way valve82opens the circulation flow path80to close the flow path85for the cooler core, so that the third pump81is operated.

Thus, a first coolant circuit (intermediate-temperature coolant circuit) indicated by an alternate long and short dash line with an arrow inFIG. 57, a second coolant circuit (low-temperature coolant circuit) indicated by a solid arrow inFIG. 57, and an internal circulation circuit indicated by an alternate long and two short dashes line with an arrow inFIG. 57are formed.

Accordingly, the first coolant circuit (intermediate-temperature coolant circuit) is formed of the second pump12, the condenser50, the heater core51, and the battery cooler15. The second coolant circuit (low-temperature coolant circuit) is formed of the first pump11, the coolant cooler14, and the radiator13. The internal circulation circuit is formed of the third pump81and the cooler core18.

That is, as indicated by the alternate long and short dash lines with arrows inFIG. 57, the coolant discharged from the second pump12is branched into the condenser50and the battery cooler15by the first switching valve19. The coolant flowing through the condenser50flows in series through the heater core51. The coolants flowing through the heater core51and through the battery cooler15are merged into the second switching valve20to be sucked into the second pump12.

On the other hand, as indicated by the solid line with the arrow inFIG. 57, the coolant discharged from the first pump11flows through the coolant cooler14via the first switching valve19. The coolant flowing through the coolant cooler14is then sucked into the second pump12via the second switching valve20and the radiator13.

Further, as indicated by the alternate long and two short dashes line with an arrow inFIG. 57, the coolant discharged from the third pump81flows through the battery cooler18to be sucked into the third pump81.

As mentioned above, in the second cooling mode, the coolant circulating through the internal circulation circuit flows through the cooler core18. Thus, the low-temperature coolant cooled by the coolant cooler14does not flow through the cooler core18.

In the following S540, it is determined whether or not the cooler core inlet water temperature exceeds a second cooling determination temperature Tf2(the second cooling determination temperature). The second cooling determination temperature Tf2is a temperature (for example, 3° C.) which is higher than the first cooling determination temperature Tf1, and is previously stored in the controller40.

When the cooler core inlet water temperature is determined to exceed the second cooling determination temperature Tf2, the operation returns to S500.

When the cooler core inlet water temperature is determined not to exceed the second cooling determination temperature Tf2, the operation returns to S540.

In this embodiment, when the cooling is required, once the cooler core inlet water temperature becomes lower than the first cooling determination temperature Tf1, the first cooling mode is switched to the second cooling mode, which can suppress the generation of the frost formation (frost) on the surface of the cooler core18. In the following, the reason for the above description will be described.

When the surface temperature of the cooler core18is lower than 0° C., the condensed water attached to the surface of the cooler core18is frozen to generate the frost formation (frost). As a result, an air passage of the cooler core18is closed to decrease the volume of blast air into the vehicle interior, reducing the air conditioning performance. Thus, the appropriate range of the temperatures of coolant flowing into the cooler core18is equal to or higher than 0° C.

From this point of view, in this embodiment, when the cooling is required, once the cooler core inlet water temperature is lower than the first cooling determination temperature Tf1in the first cooling mode, the first cooling mode is switched to the second cooling mode, so that the coolant circulating through the internal circulation circuit flows through the cooler core18, and the low-temperature coolant cooled by the coolant cooler14does not flow through the cooler core18.

At this time, the coolant circulating through the internal circulation circuit is heated by the blast air into the vehicle interior, gradually increasing its temperature. Even though the temperature of the low-temperature coolant cooled by the coolant cooler14is lower than the first cooling determination temperature Tf1, the temperature of coolant flowing through the cooler core18can be equal to or higher than the first cooling determination temperature Tf1, which can suppress the frost formation (frost) on the surface of the cooler core18.

Fourteenth Embodiment

Although in the twelfth embodiment, the third pump81is disposed in a part branched from the flow path84for the battery cooler in the circulation flow path80, in a fourteenth embodiment, as shown inFIG. 58, the third pump81is disposed in a part of the circulation flow path80which is integrated with the flow path84for the battery cooler (near the battery cooler15).

This embodiment can obtain the same operation and effects as those of the twelfth embodiment described above. Further, in this embodiment, the third pump81is operated all the time, whereby the supply of the coolant to the battery cooler15can be controlled not to be stopped in switching between the non-circulation mode (first cooling mode or the like) and the circulation mode (second cooling mode or the like).

Fifteenth Embodiment

In a fifteenth embodiment of the invention, as shown inFIG. 59, the arrangement of the coolant cooler14, condenser50, and radiator13is modified with respect to the arrangement of the above-mentioned twelfth embodiment.

The coolant cooler14is disposed between the second pump12and the first switching valve19. That is, the coolant inlet side of the coolant cooler14is connected to the coolant discharge side of the second pump12, and the coolant outlet side of the coolant cooler14is connected to the inlet19bof the first switching valve19.

The condenser50is disposed between the first pump11and the first switching valve19. That is, the coolant inlet side of the condenser50is connected to the coolant discharge side of the first pump11, and the coolant outlet side of the condenser50is connected to the inlet19aof the first switching valve19.

The radiator13is disposed between the first and second switching valves19and20. That is, the coolant inlet side of the radiator13is connected to the outlet19gof the first switching valve19, and the coolant outlet side of the radiator13is connected to the inlet20gof the second switching valve20.

The first switching valve19is configured to be capable of switching the communication state between the inlets19aand19band the outlets19c,19d,19e,19f, and19g. The second switching valve20is also configured to be capable of switching the communication state between the inlets20a,20b,20c,20d, and20gand the outlets20e, and20f.

This embodiment can obtain the same operation and effects as those of the twelfth embodiment described above.

Sixteenth Embodiment

In the above-mentioned twelfth embodiment, the coolant is allowed to circulate through the battery cooler15without flowing through the first and second switching valves19and20, which optimizes the operation of the battery, while ensuring the air conditioning performance (cooling and heating performance). On the other hand, in a sixteenth embodiment shown inFIG. 60, the battery cooler15is composed of a heat pipe type heat exchanger, which optimizes the operation of the battery, while ensuring the air conditioning performance.

The upward and downward arrows shown inFIG. 60indicate the vertical direction (direction of gravitational force) in a vehicle-mounted state. The battery cooler15includes a first gas-liquid phase changing portion151and a second gas-liquid phase changing portion152which are adapted to condense or evaporate the refrigerant (working fluid).

The first gas-liquid phase changing portion151includes a container151aand a coolant pipe151b. The refrigerant is sealed in the container151ain two phases, namely, in gas and liquid phases. The inlet side of the coolant pipe151bis connected to the outlet of the first switching valve19, and the outlet side of the coolant pipe151bis connected to the inlet of the second switching valve20. An intermediate part of the coolant pipe151bis disposed in the container151a.

The refrigerant sealed in the container151aexchanges heat with coolant flowing through the coolant pipe151bto condense or evaporate.

The second gas-liquid phase changing portion152includes a refrigerant pipe152athrough which the refrigerant flows. One end of the refrigerant pipe152ais connected to a lower portion of the container151aof the first gas-liquid phase changing portion151, that is, a portion where the liquid-phase refrigerant exists. The other end of the refrigerant pipe152ais connected to an upper portion of the container151aof the first gas-liquid phase changing portion151, that is, a portion where the gas-phase refrigerant exists.

In the second gas-liquid phase changing portion152, the refrigerant flowing through the refrigerant pipe152aevaporates or condenses by being heated or cooled by a battery90.

The battery90is composed of a plurality of battery cells. The battery90is provided with a battery temperature sensor91for detecting a temperature of the battery cells. A detection signal from the battery temperature sensor91is input to the controller40.

When the temperature of coolant flowing into the first gas-liquid phase changing portion151is low, the gas-phase refrigerant is cooled by the coolant to condense in the first gas-liquid phase changing portion151. At this time, when the liquid-phase refrigerant evaporates in the second gas-liquid phase changing portion152by being heated by the battery90, the refrigerant circulates between the first gas-liquid phase changing portion151and the second gas-liquid phase changing portion152as indicated by the arrows inFIG. 60, so that the battery90is cooled.

Conversely, when the temperature of coolant flowing into the first gas-liquid phase changing portion151(battery cooler15) is high, the liquid-phase refrigerant is heated by the coolant to evaporate in the first gas-liquid phase changing portion151. At this time, when the gas-phase refrigerant is cooled by the battery90to condense in the second gas-liquid phase changing portion152, the refrigerant circulates between the first gas-liquid phase changing portion151and the second gas-liquid phase changing portion152in the direction opposite to the direction of the arrows inFIG. 60, so that the battery90is heated.

A control process executed by the controller40of this embodiment will be described with reference toFIG. 61. The controller40executes a computer program according to a flowchart ofFIG. 61.

In S600, first, it is determined whether the battery is required to be cooled or not. Specifically, when the battery temperature is equal to or higher than a first predetermined temperature (for example, 35° C.), the cooling of the battery is considered to be required. In contrast, when the battery temperature is lower than the first predetermined temperature, the cooling of the battery is determined not to be required.

When the cooling of the battery is determined to be required, the operation proceeds to S610, in which it is determined whether the battery temperature exceeds a target cooling temperature (for example, 40° C.). When the battery temperature is determined to exceed the target cooling temperature, the operation proceeds to S620. When the battery temperature is determined not to exceed the target cooling temperature, the operation returns to S600.

In S620, the operations of the first and second switching valves19and20are controlled such that the low-temperature coolant (coolant cooled by the coolant cooler14) is supplied to the battery cooler15. Thus, the battery90is cooled.

In the following S630, it is determined whether or not the temperature of the battery cell detected by the battery temperature sensor91is lower than the first cooling determination temperature Tc1(for example, 15° C.). The first cooling determination temperature Tc1is the lower limit temperature in a range of usable temperatures of the battery (for example, 15 to 35° C.).

When the battery-cooler inlet water temperature is determined to be less than the first cooling determination temperature Tc1, the operation proceeds to S640. When the battery-cooler inlet water temperature is determined not to be less than the first cooling determination temperature Tc1, the operation returns to S610.

In S640, the operations of the first and second switching valves19and20are controlled such that the supply of the low-temperature coolant to the battery cooler15is stopped.

In the following S650, it is determined whether or not the battery-cooler inlet water temperature exceeds a second cooling determination temperature Tc2(for example, 17° C.). The second cooling determination temperature Tc2is higher than the first cooling determination temperature Tc1.

When the battery-cooler inlet water temperature is determined to exceed the second cooling determination temperature Tc2, the operation returns to S610. When the battery-cooler inlet water temperature is determined not to exceed the second cooling determination temperature Tc2, the operation returns to S650.

On the other hand, when the cooling of the battery is determined not to be required in S600, the operation proceeds to S660, in which it is determined whether the battery is required to be heated or not. Specifically, when the battery temperature is less than a second predetermined temperature (for example, 15° C.), the heating of the battery is determined to be required. In contrast, when the battery temperature is equal to or higher than the second predetermined temperature, the heating of the battery is determined not to be required.

When the heating of the battery is determined to be required, the operation proceeds to S670. When the heating of the battery is determined not to be required in S670, the operation returns to S600.

In the following S670, it is determined whether or not the battery temperature is lower than a target heating temperature (for example, 10° C.). When the battery temperature is determined to be lower than the target heating temperature, the operation proceeds to S680. When the battery temperature is determined not to be lower than the target heating temperature, the operation returns to S600.

In S680, the operations of the first and second switching valves19and20are controlled such that the high-temperature coolant (coolant heated by the condenser50) is supplied to the battery cooler15. Thus, the battery90is heated.

In the following S690, it is determined whether or not the temperature of the battery cell detected by the battery temperature sensor91is higher than the first heating determination temperature Tw1(for example, 35° C.). The first heating determination temperature Tw1is the upper limit temperature in a range of usable temperatures (for example, 15 to 35° C.) of the battery.

When the battery-cooler inlet water temperature is determined to exceed the first heating determination temperature Tw1, the operation proceeds to S700. When the battery-cooler inlet water temperature is determined not to exceed the first heating determination temperature Tw1, the operation returns to S670.

In S700, the operations of the first and second switching valves19and20are controlled so as to stop the supply of the high-temperature coolant to the battery cooler15.

In the following S710, it is determined whether or not the battery-cooler inlet water temperature is lower than the second heating determination temperature Tw2(for example, 33° C.). The second heating determination temperature Tw2is lower than the first heating determination temperature Tw1.

When the battery-cooler inlet water temperature is determined to be lower than the second heating determination temperature Tw2, the operation returns to S670. When the battery-cooler inlet water temperature is determined not to be lower than the second heating determination temperature Tw2, the operation returns to S710.

In this embodiment, when the cooling of the battery is required, once the battery cell temperature is lower than the first cooling determination temperature Tc1, the supply of the low-temperature coolant to the battery cooler15is stopped, which can prevent the reduction in input and output of the battery and in charging efficiency of the battery due to the low battery temperature which is lower than the usable temperature range.

When the battery cell temperature is gradually increased to exceed the second cooling determination temperature Tc2while the supply of the low-temperature coolant to the battery coolant15is stopped, the low-temperature coolant can be supplied to the battery cooler15to prevent the battery cell temperature from continuously increasing to much higher than the second cooling determination temperature Tc2.

Likewise, when the heating of the battery is required, once the battery cell temperature exceeds the first heating determination temperature Tw1, the supply of the high-temperature coolant to the battery cooler15is stopped, which can prevent the quick degradation of the battery, the decrease in lifetime of the battery, and the breakage of the battery due to the high battery temperature exceeding the usable temperature range.

When the battery cell temperature is gradually decreased to be lower than the second heating determination temperature Tw2while the supply of the high-temperature coolant to the battery coolant15is stopped, the high-temperature coolant can be supplied to the battery cooler15to prevent the battery cell temperature from continuously decreasing to much lower than the second heating determination temperature Tw2.

In this embodiment, the battery cooler15is composed of a heat pipe type heat exchanger, so that the difference in temperature between the battery cells forming the battery90can be reduced by action of the refrigerant even when the supply of the coolant into the battery coolant15is stopped.

Seventeenth Embodiment

Although in the above-mentioned sixteenth embodiment, the battery cooler15is composed of the heat pipe type heat exchanger, in a seventeenth embodiment, as shown inFIG. 62, the cooler core18is composed of a heat pipe type heat exchanger.

The upward and downward arrows shown inFIG. 62indicate the vertical direction (direction of gravitational force) in a vehicle-mounted state. The cooler core18includes a first gas-liquid phase changing portion181and a second gas-liquid phase changing portion182which are adapted to condense or evaporate the refrigerant. The first gas-liquid phase changing portion181includes an upper tank181a, and a coolant pipe181b. The second gas-liquid phase changing portion182includes tubes182a, fins182b, and a lower tank182c.

A number of the tubes182aform refrigerant flow paths for allowing the refrigerant to flow therethrough, and are arranged in parallel with each other to have the longitudinal direction thereof directed vertically. Air passages through which the blast air flow into the vehicle interior are formed in between the tubes182a.

The fins182bare a heat transfer promoting member for promoting the heat exchange between the refrigerant and the blast air into the vehicle interior by increasing an area of heat transfer between the tube182aand the blast air into the vehicle interior. The fins182bare bonded to the outer surfaces of the tubes182a.

Each of the upper tank181aand the lower tank182cis the tank for distributing refrigerant or collecting refrigerants with respect to the tubes182a. The upper tank181ais disposed above a large number of tubes182a, and the lower tank182cis disposed below a large number of tubes182a.

The coolant pipe181bis disposed inside the upper tank181a. The inlet side of the coolant pipe181bis connected to the outlet of the first switching valve19, and the outlet side of the coolant pipe181bis connected to the inlet of the second switching valve20.

The refrigerant is sealed in the cooler core18in two phases, namely, in gas and liquid phases. Specifically, the refrigerant is sealed in the tubes182aand lower tank182cin the liquid phase, and the refrigerant is sealed in the upper tank181ain the gas phase.

The fins182bare provided with a cooler core temperature sensor95for detecting the temperature of the fins182b, that is, the surface temperature of the cooler core18. A detection signal from the cooler core temperature sensor95is input to the controller40.

When the temperature of the coolant flowing into the coolant pipe181bis low, the gas-phase refrigerant in the upper tank181ais cooled and condensed by the coolant flowing through the coolant pipe181b. At this time, when the liquid-phase refrigerant in each tube182ais heated and evaporates by the blast air into the vehicle interior, the refrigerant circulates through between the upper tank181aand the tubes182a, thereby cooling the blast air into the vehicle interior.

A control process executed by the controller40of this embodiment will be described with reference toFIG. 63. The controller40executes a computer program according to a flowchart ofFIG. 63.

In S700, first, it is determined whether the battery is required to be cooled or not. Specifically, when the air conditioning switch44is turned on, the cooling is determined to be required. In contrast, when the air conditioning switch44is turned off, the cooling is determined not to be required.

When the cooling is determined to be required, the operation proceeds to S710. When the cooling is determined not to be required, the operation returns to S700.

In S710, the operations of the first and second switching valves19and20are controlled such that the low-temperature coolant (coolant cooled by the coolant cooler14) is supplied to the cooler core18. Thus, the blast air into the vehicle interior is cooled in the cooler core18.

In the following S720, it is determined whether or not the cooler core temperature detected by the cooler core temperature sensor95is lower than the first cooling determination temperature Tf1(for example, 1° C.). The first cooling determination temperature Tf1is a temperature determined based on the lower limit temperature in a range of temperatures that does not cause the frost formation (frost) on the surface of the cooler core18, and is previously stored in the controller40.

When the cooler core temperature is determined to be less than the first cooling determination temperature Tf1, the operation proceeds to S730. When the cooler core temperature is determined not to be less than the first cooling determination temperature Tf1, the operation returns to S700.

In S730, the operations of the first and second switching valves19and20are controlled such that the supply of the low-temperature coolant to the cooler core18is stopped.

In the following S740, it is determined whether or not the cooler core temperature exceeds a second cooling determination temperature Tf2(for example, 3° C.). The second cooling determination temperature Tf2is a temperature (for example, 3° C.) which is higher than the first cooling determination temperature Tf1, and is previously stored in the controller40.

When the cooler core temperature is determined to exceed the second cooling determination temperature Tf2, the operation returns to S700. When the cooler core temperature is determined not to exceed the second cooling determination temperature Tf2, the operation returns to S740.

In this embodiment, when the cooling of the battery is required, once the cooler core temperature becomes lower than the first cooling determination temperature Tf1, the supply of the low-temperature coolant to the cooler core18is stopped, which can suppress the generation of the frost formation (frost) on the surface of the cooler core18.

When the cooler core temperature is gradually increased to exceed the second cooling determination temperature Tf2while the supply of the low-temperature coolant to the cooler core18is stopped, the low-temperature coolant can be supplied to the cooler core18to prevent the cooler core temperature from continuously increasing to much higher than the second cooling determination temperature Tf2.

Other Embodiments

The present disclosure is not limited to the above-mentioned embodiments, and various modifications and changes can be made to the disclosed embodiments as follows.

(1) Various devices can be used as the temperature adjustment devices. For example, the temperature adjustment device for use may be a heat exchanger incorporated in a seat where a passenger sits and adapted to cool and heat the seat by coolant. The number of temperature adjustment devices may be any number as long as the number is a plural number (two or more).

(2) The above first embodiment shows one example of the arrangement pattern of holes formed in valve elements of the first and second switching valves19and20. However, the arrangement pattern of holes formed in the valve elements of the first and second switching valves19and20can be changed in various manners.

The communication state between the inlet and outlet for the coolant can be changed in a variety of ways by modifying the arrangement pattern of the holes formed in the valve elements of the first and second switching valves19and20, which can easily adapt to the change of specifications, including addition of an operating mode and the like.

(3) Although in the above first embodiment, the switching is performed among the first to third modes based on the outside air temperature detected by the outside air sensor42, the switching among the first to third modes may be performed based on the coolant temperature detected by the water temperature sensor43.

(4) Although in the above third embodiment, the cold energy stored in the battery is used to supercool the high-pressure refrigerant of the refrigeration cycle22in the second mode, the cold energy stored in the battery may be used to cool the air of the vehicle interior, the inverter, and the like.

(5) In the embodiments described above, the coolant cooler14for cooling the coolant by the low-pressure refrigerant of the refrigeration cycle22is used as the cooler for cooling the coolant down to a lower temperature than the outside air temperature. However, a Peltier device may be used as the cooler.

(6) In each of the above-mentioned embodiments, the coolant may intermittently circulate through the battery cooler15to thereby control the cooling capacity for the battery.

(7) In each of the above-mentioned embodiments, the switching may be performed between a state of circulation of the intermediate-temperature coolant through the exhaust gas cooler17and another state of circulation of the low-temperature coolant therethrough according to a load on an engine. When a load on the engine is small, for example, while the vehicle is traveling in midtown, the switching can be performed to the low-temperature coolant circulation to cool the exhaust gas by the refrigeration cycle22, resulting in an increase in density of exhaust gas returned to the engine intake side, thereby improving the fuel efficiency.

(8) In each of the above-mentioned embodiments, the coolant is used as the heat medium for cooling or heating the temperature adjustment device. Alternatively, various kinds of media, such as oil, may be used as the heat medium.

(9) The refrigeration cycle22of each of the above embodiments employs a fluorocarbon refrigerant as the refrigerant. However, the kind of the refrigerant is not limited thereto. Specifically, a natural refrigerant, such as carbon dioxide, a hydrocarbon-based refrigerant, and the like may also be used as the refrigerant.

The refrigeration cycle22of each of the above embodiments forms a subcritical refrigeration cycle whose high-pressure side refrigerant pressure does not exceed a critical pressure of the refrigerant. Alternatively, the refrigeration cycle22may form a supercritical refrigeration cycle whose high-pressure side refrigerant pressure exceeds the critical pressure of the refrigerant.

(10) In each of the above-mentioned embodiments, the vehicle thermal management system of the present disclosure is applied to the hybrid car by way of example. Alternatively, the present disclosure may be applied to an electric vehicle which obtains a driving force for traveling from an electric motor for traveling without including an engine.

(11) In the above twelfth to fifteenth embodiments, the three-way vale82is adapted to switching between opening and closing of the circulation flow path80and the flow path84for the battery cooler by the three-way valve82. Alternatively, the three-way valve82is removed, and then a check valve may be provided in the circulation flow path80.

In this case, the first and second switching valve19and20close the flow path84for the battery cooler, so that the switching can be performed to the circulation mode (second cooling mode, second heating mode, battery temperature equalization operating mode, or second cooling mode). Alternatively, the switching can also be performed to the circulation mode by causing the first switching valve19to connect the flow path84for the battery cooler to one of the first and second coolant circuits, and also causing the second switching valve20to connect the flow path84for the battery cooler to the other of the first and second coolant circuits.

(12) In the twelfth to fifteenth embodiments, the internal circulation circuit is formed in the battery cooler15or cooler core18by way of example. However, the invention is not limited thereto, and the internal circulation circuit may be formed for other temperature adjustment devices.

For example, the internal circulation circuit may be formed for the inverter cooler16. Thus, the cooling capacity of the inverter can be adjusted to be prevented from excessively increasing due to the introduction of the low-temperature coolant into the inverter cooler16on traveling conditions with the small amount of heat generated by the inverter.

(13) Although in the above sixteenth embodiment, the coolant is intermittently supplied into the battery cooler15according to the temperature of the battery90, the flow rate of the coolant supplied to the battery cooler15may be adjusted according to the temperature of the battery90.

Likewise, although in the above seventeenth embodiment, the coolant is intermittently supplied into the cooler core18according to the temperature of the cooler core18, the flow rate of the coolant supplied to the cooler core18may be adjusted according to the temperature of the cooler core18.

The flow rate of the coolant can be adjusted by controlling the operation of at least one of the first and second switching valves19and20.

(14) The cooler core18of the above seventeenth embodiment may be provided with a refrigerant pipe for returning the refrigerant condensed in the upper tank181adirectly to the lower tank182c.