CROSS-REFERENCE TO RELATED APPLICATIONS

This Patent Application claims priority from Italian Patent Application No . 102021000022877 filed on September 3 , 2021 , the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention concerns a heat management system, in particular a heat management system for a fuel cell vehicle .

The present invention finds its preferred, although not exclusive , application in a heavy vehicle such as a truck; reference will be made to this application by way o f example below .

BACKGROUND OF THE INVENTION

Fuel cell vehicles comprise fuel cell modules that need to be maintained within a preset range of temperature . Accordingly, fuel cell modules need to be cooled or to be heated according to the vehicle operation and to environment conditions .

Furthermore , such need is common with other operating modules of the vehicle such as the brake resistors , the cabin or battery modules .

In order to provide a correct management of the temperatures of all such elements , each of them is provided with a speci fic heat management system that foresees the presence of heat exchangers , expansion tanks and ventilation means .

The aforementioned heat management systems clearly increases the complexity of the vehicle , reduces the useful spaces thereon and increases the manufacturing costs .

Moreover, the use of the known heat management systems foresees the use of electrical energy therefore reducing the ef ficiency of the vehicle .

Therefore , the need is felt to manage heat transmission into fuel cell vehicles to improve the ef ficiency of the system while saving costs , reducing encumbrances and allowing the operation of the di f ferent operational systems of the vehicle .

An aim of the present invention is to satis fy the above mentioned needs in a cost ef fective and optimi zed way .

SUMMARY OF THE INVENTION

The aforementioned aim is reached by a heat management system as claimed in the appended set of claims .

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the present invention, a preferred embodiment is described in the following, by way of a non-limiting example , with reference to the attached drawings wherein :

• Figure 1 is hydraulic schematic of the heat management system according to the invention;

• Figure 2 is hydraulic schematic of the heat management system according to the invention in a first operative condition;

• Figure 3 is hydraulic schematic of the heat management system according to the invention in a second operative condition;

• Figure 4 is hydraulic schematic of the heat management system according to the invention in a third operative condition;

• Figure 5 is hydraulic schematic of the heat management system according to the invention in a fourth operative condition;

• Figure 6 is hydraulic schematic of the heat management system according to the invention in a fi fth operative condition; and

• Figure 7 is hydraulic schematic of the heat management system according to the invention in a sixth operative condition .

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 discloses in a schematic way a heat management system 1 for a heavy vehicle such as a truck (not shown) .

The heavy vehicle comprises a fuel cell module 2 is configured, as known, to provide electrical energy via chemical reaction between hydrogen and oxygen .

The heavy vehicle further comprises a battery module 3 configured to store and allow the utili zation of the electrical energy provided by the fuel cell module 2 .

The heavy vehicle further comprises brake resistor means 4 configured to impart a braking torque on a rotating shaft , in order to brake the vehicle , via production of electrical energy and its dissipation as heat .

The heavy vehicle is provided with a cab (not shown) for housing a driver during the use of the vehicle and therefore the heavy vehicle comprises a cab heater 5 configured to provide heat to the housing space of the cab .

According to the invention, the heat management system 1 is configured to fluidly connect together , at least indirectly, the fuel cell module 2 , the battery module 3 , the brake resistor means 4 , the cab heater 5 , a plurality of heat exchangers 6 , 7 , 8 and at least an expansion tank 9 via a plurality of conduits and valve means to allow the trans fer of heat among the fuel cell module 4 , the battery module 3 , the brake resistor means 4 and the cab heater 5 in function of their temperature and their operational status .

In detail , according to the advantageous disclosed embodiment represented in figure 1 , the heat management system 1 comprises a fuel cell portion 1 ' comprising a first conduit 11 and a second conduit 12 fluidly connecting the fluid cell module 2 and a fuel cell radiator 6 ' fluidly in series one with respect to the other .

The fuel cell portion 1 ' further comprises a by-pass conduit 13 fluidly interposed between first and second conduits 11 , 12 in parallel with respect to fuel cell radiator 6 ' to bypass this latter . Advantageously, by-pass conduit 13 is fluidly connected to second conduit 12 via a T-j unction while it is connected to first conduit 11 via valve means 14 configured to make fluid flow towards the fuel cell radiator 6 ' or the by-pass conduit 13 .

Moreover, fuel cell portion 1 ' i s provided with pump means 15 fluidly interposed in one between first and second conduits 11 , 12 , in the discloses embodiment in second conduit 12 , and configured to make refrigerant flow recirculate between the conduits 11 , 12 and 13 , in particular from the fuel cel l radiator 6 ' towards the fuel cel l module 2 .

Fuel cell portion 1 ' may further comprise a fuel cell expansion tank 9 ' fluidly connected to one between first and second conduits 11 , 12 , in the discloses embodiment to second conduit 12 upstream to valve means 15 , and configured to allow the expansion of conditioning fluid according to its temperature , as per se known .

The heat management system 1 comprises a battery portion 1 ' ' comprising a first conduit 21 and a second conduit 22 fluidly connecting the battery module 3 and a battery radiator 6 ' ' in series one with respect to the other .

The battery portion 1 ' ' further comprises a by-pass conduit 23 fluidly interposed between first and second conduits 21 , 22 in parallel with respect to battery radiator 6 ' ' to bypass this latter . Advantageously, by-pass conduit 23 is fluidly connected to second conduit 22 via a T-j unction while it is connected to first conduit 21 via valve means 24 configured to make fluid flow towards the battery radiator 6 ' ' or the by-pass conduit 23 . The battery portion 1 ' ' further comprises a chiller 7 fluidly interposed on by-pass conduit 23 .

It is noticed that with chiller 7 it is meant a radiator provided with conditioning means for actively withdrawing heat into environment while a passive dissipater is intended a mere radiator provided with ventilation means to withdraw into environment heat without the use of a conditioning cycle apparatus .

Moreover, battery portion 1 ' ' is provided with pump means 25 fluidly interposed in one between first and second conduits 21 , 22 , in the discloses embodiment in first conduit 21 , and configured to make refrigerant flow recirculate between the conduits 21 , 22 and 23 , in particular from the battery radiator 6 ' ' towards the battery module 4 .

Battery portion 1 ' ' may further comprise a battery expansion tank 9 ' ' fluidly connected to one between first and second conduits 21 , 22 , in the discloses embodiment to first conduit 21 upstream to pump means 25 , and configured to allow the expansion of conditioning fluid according to its temperature , as per se known . The heat management system 1 comprises a brake resistor portion 1' ' ' comprising a first conduit 31 and a second conduit 32 fluidly connecting the cab heater 5 and the brake resistor means 4 in series one with respect to the other.

Brake resistor portion 1' ' ' is provided with pump means 33 fluidly interposed in one between first and second conduits 31, 32, in the discloses embodiment in second conduit 32, and configured to make refrigerant flow recirculate between the conduits 31 and 32, in particular from the cab heater 5 towards brake resistor means 4.

Brake resistor portion 1' ' ' may further comprise a brake resistor expansion tank 9' ' ' fluidly connected to one between first and second conduits 31, 32, in the discloses embodiment to second conduit 32 upstream to pump means 33, and configured to allow the expansion of conditioning fluid according to its temperature, as per se known.

The brake resistor portion 1' ' ' and the fuel cell portion 1' , such as the battery portion 1' ' and the fuel cell portion 1' are fluidly separated one with respect to the other, i.e. the conditioning fluid of fuel cell portion 1' is different with respect to the conditioning fluid flowing into brake resistor portion 1' ' ' and battery portion 1' ' .

In particular, the brake resistor portion 1' ' ' comprises a heat exchanger 8 configured to allow the heat transfer between the conditioning fluids flowing into the fuel cell portion 1' and brake resistor portion 1' ' ' . Accordingly, the heat exchanger 8 is designed so as to maintain the two conditioning fluid flows separated one with respect to the other.

In the disclosed embodiment, according to the above configuration, heat exchanger 8 is a counter-flow heat exchanger .

Advantageously, brake resistor portion 1' ' ' and battery portion 1' ' are fluidly connected via a plurality of connection conduits 41, 42, 43, 44, as described hereinafter, therefore the conditioning fluid that flows in brake resistor portion 1' ' ' and battery portion 1' ' is the same.

In detail, the heat management system 1 comprises a first connection conduit 41 configured to fluidly connect a point on second conduit 32 of brake resistor portion 1' ' ' fluidly interposed between heat exchanger 8 and cab heater 5, preferably via a T-joint, with second conduit 22 of the battery portion 1' ' downstream to battery radiator 6' ' , preferably via valve means 41' .

Furthermore, the heat management system 1 comprises a second connection conduit 42 configured to fluidly connect a point on first connection conduit 41, preferably via a T- joint, with first conduit 21 of the battery portion 1' ' in a point fluidly interposed between battery module 3 and battery radiator 6' ' , preferably via valve means 42' . Second connection conduit 42 is furthermore fluidly connected between the aforementioned T-joint and the valve means 42 to second conduit 32 of brake resistor portion 1' ' ' .

Furthermore, the heat management system 1 comprises a third connection conduit 43 configured to fluidly connect a point on second conduit 32 of brake resistor portion 1' ' ' fluidly interposed between the connection of second connection conduit 42 and the brake resistor expansion tank 9' ' ' , preferably via a T-joint, with first conduit 21 of the battery portion 1' ' in a point fluidly interposed between the battery expansion tank 9' ' battery radiator 6' ' , preferably via a T-j oint .

Moreover, the heat management system 1 comprises a fourth connection conduit 44 configured to fluidly connect a point on first conduit 31 of brake resistor portion 1 ' ' ' fluidly interposed between the connection o f third connection conduit 43 and the brake resistor expans ion tank 9 ' ' ' ( and as represented preferably coincident with its fluidic connection point ) , preferably via a T-j oint , with second conduit 22 of the battery portion 1 ' ' in a point fluidly interposed between the battery radiator 6 ' ' and bypass conduit 23 , preferably via a valve means 44 ' .

Heat management system 1 is furthermore provided with on-of f valves configured to allow or deny the flow of fluid on the respective conduit according .

In particular, according to the described configuration, heat management system 1 comprises :

- A first valve 31 ' fluidly interposed on the second conduit 32 of the brake resistor portion 1 ' ' ' between the connection of the second connection conduit 42 and the heat exchanger 8 ;

A second valve 31 ' ' fluidly interposed on the first conduit 31 of the brake resistor portion 1 ' ' ' between the connection of the third connection conduit 43 and the cab heater 5 ;

- A third valve 41 ' ' fluidly interposed on the first connection conduit 41 between the connection of the second connection conduit 42 and the brake resistor portion 1 ' ' ' ;

A fourth valve 42 ' ' fluidly interposed on the second connection conduit 42 between the connection with the first connection conduit 41 and the brake resistor portion 1 ' ' ' ; and

- A fi fth valve 43 ' fluidly interposed on the third connection conduit 43 .

The aforementioned valves and pump means disclosed in the portions and conduits are preferably electrically controlled via an electronic control unit , not shown, configured to vary their status .

In particular, work vehicle is provided with temperature sensor means conf igured to detect the temperature of the fuel cell module 2 , of battery module 3 , of brake resistor means 4 and of cab heater 5 . Such sensor means are electrically connected to the electronic control unit that comprises elaboration means suitable for elaborating the temperature value detected by these latter and control consequently the valves and pump means of heat management system 1 .

The operation of the above described heat management system 1 is the following .

According to a first operative mode , shown in figure 2 , the fuel cell module 2 is detected as below a lower temperature threshold, i . e . it is too cold . Accordingly, brake resistor means 4 provide a heat flow within brake resistor portion 1 ' ' ' to the conditioning fluid flowing therein . In particular, valves 41 ' ' , 42 ' ' , 43 ' , 44 ' and 42 ' do not allow the fluid to pass through themselves and therefore conditioning fluid flows only in conduits 31 , 32 carried by pump means 33 . The heated conditioning fluid from brake resistor means 4 passes through heat exchanger 8 providing a heat flow to the fuel cell module that increases its temperature . Such condition may be maintained till necessary to make temperature over the aforementioned lower threshold. As shown, the heat flow provided by the brake resistor means 4 may also be used by passing into cab heater 5 to provide a heat flow to cab of the vehicle, if also this later is too cold. During such operation the battery portion 1' ' is isolated from the other operation and valve means 14 are controlled to bypass fuel cell radiator 6' .

According to a second operative mode, shown in figure 3, the fuel cell module 2 and the battery module 3 are detected as below respective lower temperature thresholds, i.e. they are too cold. Accordingly, brake resistor means 4 provide a heat flow within brake resistor portion 1' ' ' to the conditioning fluid flowing therein. In particular, valves 41' ' , 42' ' , 43' do not allow the fluid to pass through themselves while valves 42' and 44' allows the passage within the battery portion 1' ' . Therefore, the heated conditioning fluid from brake resistor means 4 passes through heat exchanger 8 providing a heat flow to the fuel cell module that increases its temperature while part is deviated into conduit 21 thereby being pumped toward battery module 3 increasing also its temperature. Such two flows then join together upstream pump means 13 and are sent again to brake resistor means 4. Such condition may be maintained till necessary to make temperature over the aforementioned lower thresholds. As shown, the heat flow provided by the brake resistor means 4 may also be used by passing into cab heater 5to provide a heat flow to cab of the vehicle, if also this later is too cold. During valve means 14 are controlled to bypass fuel cell radiator 6' .

According to a third operative mode, shown in figure 4, the fuel cell module 2 and the battery module 3 are detected as over respective upper temperature thresholds, i.e. they are too hot, while brake resistor means 4 are not working. In particular, valves 24 and 42' are controlled to allow the circulation of conditioning fluid only between chiller 7 and battery module 3 while valves 41' , 43'31' , 41' ' are controlled to include in brake resistor portion 1' ' ' also battery heat exchanger 6' ' . Valve means 14 are instead controlled to make a great part of flow of conditioning fluid to flow into fuel cell radiator 6' . Then heat from battery module 3 is transferred to conditioning fluid that is flow to chiller 7 wherein it is dissipated into environment. Instead, fuel cell module 2 provides heat to conditioning fluid that flows towards fuel cell radiator 6' dissipating heat into environment. When returning towards the fuel cell module, part of the conditioning fluid flows towards heat exchanger 8 thereby subcooling and providing a heat flow to the brake resistor portion 1' ' ' . In this latter such heat is flow to battery radiator 6' ' and there dissipated into environment. If needed, part of such heat could be used into cab heater 5.

According to a fourth operative mode, shown in figure 5, the fuel cell module 2 and the battery module 3 are detected as over respective upper temperature thresholds, i.e. they are too hot, while brake resistor means 4 are working. In particular, valves 24 and 42' are controlled to allow the circulation of conditioning fluid only between chiller 7 and battery module 3 while valves 41' , 43' , 42' ' are controlled to include in brake resistor portion 1' ' ' also battery heat exchanger 6' ' and to exclude the heat exchanger 8. Valve means 14 are instead controlled to make a great part of flow of conditioning fluid to flow into fuel cell radiator 6' . Then heat from battery module 3 is transferred to conditioning fluid that is flow to chiller 7 wherein it is dissipated into environment. Instead, fuel cell module 2 provides heat to conditioning fluid that flows towards fuel cell radiator 6' dissipating heat into environment. On the other hand the brake resistor means 4 provide heat to the conditioning fluid that flows towards battery radiator 6' ' and is dissipated into environment. If needed, part of such heat could be used into cab heater 5. In this case, not shown in the drawings, valve 31' ’ is open.

According to a fifth operative mode, shown in figure 6, the fuel cell module 2 and the battery module 3 are detected as over respective upper temperature thresholds, i.e. they are too hot, while brake resistor means 4 are not working. In particular, valves 24 and 42' are controlled to allow the circulation of conditioning fluid only between chiller 7 and battery module 3 while valves 41' , 43' , 42' ' are controlled to include in brake resistor portion 1' ' ' also battery heat exchanger 6' ' and to exclude the heat exchanger 8. Valve means 14 are instead controlled to make a great part of flow of conditioning fluid to flow into fuel cell radiator 6' . Then heat from battery module 3 is transferred to conditioning fluid that is flow to chiller 7 wherein it is dissipated into environment. Instead, fuel cell module 2 provides heat to conditioning fluid that flows towards fuel cell radiator 6' dissipating heat into environment.

On the other hand the conditioning fluid flows for security reason into brake resistor portion 1' ' ' without providing heat exchanges.

According to a sixth operative mode, shown in figure 7, the fuel cell module 2 and the battery module 3 are detected as over respective upper temperature thresholds , i . e . they are too hot , while brake resistor means 4 are not working . In particular, valves 24 and 42 ' are controlled to allow the circulation o f conditioning fluid only between battery radiator 6 ' ' and battery module 3 while valves 41 ' ' , 43 ' , 31 ' ' are controlled make circulate conditioning fluid in brake resistor portion 1 ' ' ' only between brake resistor means 4 and cabin heater 5 . Valve means 14 are instead controlled to make a great part of flow of conditioning fluid to flow into fuel cell radiator 6 ' . Then heat from battery module 3 is trans ferred to conditioning fluid that is flow to battery radiator 6 ' ' wherein it is dissipated into environment . Instead, fuel cell module 2 provides heat to conditioning fluid that flows towards fuel cell radiator 6 ' dissipating heat into environment . On the other hand the conditioning fluid flows for security reason into brake resistor portion 1 ' ' ' without providing heat exchanges .

In view of the foregoing, the advantages of a heat management system for a fuel cell vehicle according to the invention are apparent .

Thanks to the proposed heat management system there all the operative elements of the vehicle are fluidly connected together, it is possible to ef ficiently allow heat trans fer according to their needs .

Moreover, since fuel cell conditioning circuit is fluidly separated with respect to the battery and brake resistor conditioning circuit , there is no problem of contamination that could lead to wear due to chemical reactions in conduits .

Thanks to the combination of all the elements together it is possible : - To use fuel cell and/or brake resistor heat to warm cab of the vehicle and/or battery module; and

- To use the heat exchangers of battery module and/or brake resistor/cab heater as additional heat exchangers for cooling down fuel cell and/or brake resistor (and even battery module, if needed) .

In view of the above, it may be sufficient to use radiators (i.e. passive heat exchangers) instead of using chillers that need active conditioning means, except for exceptional circumstances.

Accordingly, not only the heat management system is compact and requires less elements, thereby being less costly, but, moreover, it allows reducing energy consumption on the vehicle.

It is clear that modifications can be made to the described heat management system for a fuel cell vehicle that do not extend beyond the scope of protection defined by the claims.

For example, the relative topology of conduits, valve and pump means may be varied according to the typology and dimension of the elements of the vehicle.

Furthermore, the heat exchanger and the pump means, such as temperature sensor means, may be of any typology.