IT201800004695A1 - Improved Motor Vehicle Air Conditioning. - Google Patents

Description

"Improved air conditioning for motor vehicles"

The present invention relates to an air conditioner for motor vehicles, particularly, but not exclusively, useful and practical for cooling and heating passenger cars, commercial vehicles and work vehicles.

Nowadays, air conditioning systems that allow the passenger compartment to be cooled and / or heated are considered an almost indispensable accessory for any vehicle with a passenger compartment.

The air conditioners are in fact installed on the vast majority of vehicles on the market, both those for private use, such as typically cars, and those for commercial, tourist or industrial use, such as vans, buses, agricultural and construction vehicles.

The air conditioners installed in the vehicles make it possible to maintain optimal temperature and humidity conditions inside the passenger compartment, even in the presence of very high or very low external temperatures, to the benefit of the comfort and health of the occupants.

Known vehicle air conditioners consist of refrigerating systems that use a compression / expansion refrigeration thermodynamic cycle.

More in detail, these known systems comprise an electromechanical compressor which compresses a gas, the temperature of which increases due to the reduction of its volume.

The compressed gas then passes into a condenser, consisting of a heat exchanger in thermal communication with the external environment, where it loses heat, passing from the gaseous phase to the liquid phase.

Once cooled, the pressurized fluid passes into a second heat exchanger in which it is put in thermal communication with the air of the environment to be refrigerated and in which it is made to expand, lowering the pressure, through a lamination valve inside. of which there is a nozzle that makes the liquid expand with the minimum possible entropy. In practice, the liquid, through the lamination valve, is vaporized by cooling the surrounding air.

Once through the second heat exchanger, the low pressure fluid returns to the compressor to start a new cycle.

According to the known art, the heating function is instead normally performed by exploiting the heat generated by the vehicle engine, conveying the heated air inside the passenger compartment by passing it through a suitable radiator connected to the engine cooling circuit.

Sometimes, an electrical resistance is also provided to supplement the radiator, which allows the air to be heated more quickly in the initial phases of use of the vehicle, in which the engine temperature is still relatively low.

The air conditioning systems for vehicles in use today, although very useful and practical, have the significant limitation of being able to operate exclusively with the vehicle engine running.

In fact, the electromechanical compressor needs to be powered, directly or indirectly, by the vehicle engine.

Furthermore, even the heating of the air can only take place thanks to the heat generated by the engine during its operation.

Some known types of air conditioning systems for vehicles overcome this limit by providing an additional independent motor for powering the compressor and / or electrical resistances for heating. However, this solution has the considerable disadvantage of being very noisy, as well as very polluting due to engine emissions.

Furthermore, this solution is also economically disadvantageous due to the consumption of the additional engine.

Another disadvantage of this solution is represented by the costs for the installation and maintenance of the additional motor.

Another disadvantage common to all known vehicle air conditioning systems is represented by the fact that the refrigerant gases used are particularly harmful to the environment.

A further disadvantage of air conditioning systems for vehicles of the known type is represented by the fact that the presence of electromechanical parts in motion (such as for example the parts of the compressor) makes them particularly prone to failures and not entirely reliable.

The aim of the present invention is to provide an air conditioner for vehicles which solves the technical problem described above, obviates the drawbacks and overcomes the limits of the known art, allowing the passenger compartment to be cooled and heated even when the engine is not running.

Within the scope of this aim, an object of the present invention is to provide an air conditioning system for vehicles which has a lower environmental impact if compared to the known art.

Another object of the invention is to provide a more silent air conditioning system for vehicles than in the known art.

A further object of the invention is to provide an air conditioning system for vehicles with limited consumption.

Another object of the invention is to provide an air conditioning system which allows to increase the efficiency of the vehicle on which it is installed, in terms of lower consumption, less pollution and greater engine power available.

Another object of the invention is to provide an air conditioning system for vehicles which is more reliable and less subject to breakdowns if compared to the known art.

Not least object of the invention is to provide an air conditioning system for vehicles which is easy to manufacture and economically competitive if compared to the known art.

The aforementioned aim, as well as the aforementioned objects and others which will appear more clearly later on, are achieved by an air conditioner for air conditioning the passenger compartment of a vehicle of the type provided with an internal combustion engine,

characterized in that it includes an absorption refrigeration unit which in turn includes:

- a refrigeration circuit adapted to contain a fluid compound and comprising at least one evaporator placed in thermal communication with the passenger compartment of the vehicle and

- a duct suitable for conveying the exhaust gases of the internal combustion engine, the duct being placed in thermal communication with the refrigeration circuit, the exhaust gases flowing within said duct heating said fluid compound in such a way as to evaporate at least a part of it making it circulate in the refrigeration circuit towards the evaporator.

This aim and these and other objects are also achieved by a method according to claim 10.

Further characteristics and advantages of the invention will become clearer from the description of a preferred but not exclusive embodiment of an air conditioner for motor vehicles, illustrated by way of non-limiting example with the aid of the attached drawings in which:

Figure 1 is a block diagram of the air conditioner for motor vehicles according to the invention;

Figure 2 is a schematic representation of a possible embodiment of an air conditioner according to the invention, in a cooling configuration;

Figure 3 is a schematic representation of the air conditioner of Figure 2, in a cooling configuration.

With reference to the aforementioned figures, the air conditioner for motor vehicles, motor boats and the like, globally indicated with the reference number 10, is intended for the air conditioning of the passenger compartment A of a motor vehicle, and more precisely of a vehicle equipped of an internal combustion engine (fed by any type of fuel) 33 and of a tank 29 adapted to contain a fuel F for feeding this engine.

A motor vehicle therefore means any vehicle both for the transport of passengers (such as cars, minibuses, coaches, campers, etc.), and vehicles for transporting goods (such as trucks, cabin forklifts, etc.), and work vehicles (such as agricultural or construction vehicles with cabs). In practice, the present invention can be used on any vehicle as long as it is equipped with a passenger compartment and an engine 33 fed at least partially with fuel F present in a tank 29 (thus including so-called hybrid vehicles).

Also the fuel F is to be understood, in a completely general way, any fuel, both liquid and gaseous, suitable for powering an engine 33 (such as for example petrol, diesel, LPG, methane, etc.) normally contained in the tank 29 of the vehicle.

According to the invention, the air conditioner 10 comprises an absorption refrigeration unit 100 which in turn comprises a refrigeration circuit 90 and a duct 20 placed in thermal communication with this refrigeration circuit 90. The duct 20 receives inlet the exhaust gases of the internal combustion engine with which the vehicle is provided and which is fed with the fuel F present in the tank 29 of the vehicle.

It should be noted that, from now on, the term "in thermal communication" is understood to be operationally connected in such a way as to be able to reciprocally exchange heat, that is to say that two elements described as "in thermal communication" are to be understood as capable to exchange heat either directly (by contact, radiation or convection) or indirectly (being connected through a thermal conductor or a flow of a heat transfer fluid).

Returning to the air conditioner 10, according to the invention, the refrigeration circuit 90 comprises at least one evaporator 50 placed in thermal communication with the passenger compartment A of the vehicle.

At least during operation, a fluid compound SR is contained within the refrigeration circuit 90, which flows inside the circuit 90, partly in the liquid phase and partly in the gaseous phase, as normally occurs in known absorption refrigerant circuits. and how it will become clearer later.

The fluid compound SR is preferably constituted by a binary compound SR comprising a refrigerant fluid R and a solvent S.

Even more preferably, this binary compound SR consists of lithium bromide and water (H20-BrLi), where water (H20) is the refrigerant fluid R and lithium bromide (BrLi) is the solvent S, or ammonia and water (NH3-H20), where ammonia (NH3) is the refrigerant fluid R and water (H20) is the solvent S.

Note that these binary compounds are less harmful to the environment than the refrigerant gases normally used in compressor air conditioners.

In other possible embodiments, the fluid compound SR consists of any other chemical solution suitable for operating an absorption thermodynamic cycle.

According to the invention, the refrigeration circuit 90 can be configured at least in a cooling configuration for cooling the passenger compartment A and preferably also in a heating configuration for heating the passenger compartment A. The configuration of the refrigeration circuit 90, in cooling configuration and possibly in heating configuration, is carried out according to the known art, preferably according to what is normally carried out in known type absorption heat pumps.

The passage from the cooling configuration to the heating configuration also takes place in known ways.

Preferably, there is also a user interface provided with a thermostat and control electronics which allows the user to control the operation of the refrigeration unit 100 and, if necessary, to pass from the cooling configuration to the heating configuration.

One of the possible embodiments of the refrigeration circuit 90 is schematically represented in Figure 3 where the circuit 90 is represented, respectively, in a cooling configuration and in a heating configuration.

With reference to Figure 3, the exhaust gas duct 20 is, as mentioned, in thermal communication with the refrigeration circuit 90 and, more precisely, the exhaust gases allow the fluid compound SR to be heated in such a way as to make it evaporate at least a part by making it circulate in the circuit 90 towards the evaporator 50. More in detail, in the preferred embodiments, the exhaust gases present in the duct 20 heat the binary compound SR by evaporating a substantial part of the refrigerant fluid R, thus separating it from the solvent S and creating a pressure which pushes it in the circuit 90 towards the evaporator 50.

Preferably, this heating of the binary compound SR with consequent separation of the refrigerant fluid R takes place inside a generation chamber 30, consisting for example of a desorbator or a boiler (or what is generically defined in the branch as "generator"), placed in thermal communication with the duct 20.

In the example schematically illustrated in Figure 3, the refrigeration circuit 90 comprises a generation chamber 30 in thermal communication with the duct 20 and in fluid communication with a condenser 40, which condenser 40 is in thermal communication with the external environment E is in fluid communication with evaporator 50, which evaporator 50 is in fluid communication with an absorption chamber 60, which absorption chamber 60 is in turn in fluid communication with the generation chamber 30.

It is useful to specify that by indicating two elements as "in fluid communication" it is meant here that these two elements are connected, preferably by means of a conduit, in such a way that a fluid can flow from one element to another.

Returning in greater detail to the elements which, in the example illustrated, make up the refrigeration circuit 90, the condenser 40 is preferably constituted by a heat exchanger (for example a coil) in which the refrigerant fluid R releases heat to the external environment E (in the cooling configuration) or to passenger compartment A (in the heating configuration), passing from the gas to the liquid phase.

The vaporizer 50 is, as known, an element inside which the refrigerant fluid R is evaporated at very low pressure, cooling and absorbing heat from the surrounding air, cooling it (and therefore absorbing heat from the passenger compartment A when the refrigeration circuit 90 is in cooling configuration or from the external environment AND when in heating configuration).

It should be noted that, preferably, in the heating configuration the condenser 40 is placed in thermal communication with the passenger compartment A and the evaporator 50 is placed in thermal communication with the external environment E, so that the refrigerant fluid R is released heat to the passenger compartment A and absorbed heat from the external environment E.

Vice versa, in the cooling configuration, the condenser 40 is placed in thermal communication with the external environment E and the evaporator 50 is placed in thermal communication with the passenger compartment A, in such a way that heat is transferred from the refrigerant fluid R to the external environment E and absorbed heat from the passenger compartment A.

The passage of the refrigerant fluid R in the low pressure vapor state is preferably caused by at least one lamination valve 51 located upstream of the evaporator 50.

To facilitate the passage of the cooled air from the evaporator 50 (and possibly, in the heating configuration, of the air heated by the condenser 40) to the passenger compartment, a ventilation system can be provided comprising one or more ventilation elements 99, 99 'such as for example one or more fans.

Optionally, the evaporator 50 and / or the condenser 40 is placed in thermal communication with a heat-carrying liquid, preferably water, which in turn is placed in thermal communication with the passenger compartment A (for example by circulating within a circuit comprising exchangers of heat placed in thermal communication with the passenger compartment A).

The absorption chamber 60 is connected to the generation chamber 30 by means of a delivery duct 61 for the passage of the solvent S (or in any case part of the binary compound SR not evaporated and poor in refrigerant fluid R) from the generation chamber 30 to the absorption 60 and a return conduit 62 for the passage of the binary compound SR (recombined in the absorption chamber 60) from the absorption chamber 60 to the generation chamber 30.

The absorption chamber 60 is, in other words, a chamber into which the refrigerant fluid R coming from the vaporizer 50 and the solvent S coming from the generation chamber 30 converge, in such a way as to be able to recombine to form the binary compound SR.

In practice, the gases present in the duct 20 and passing through this duct heat the binary compound SR in the generation chamber 30 and evaporate at least part of the refrigerant fluid R, separating it from the solvent S and pushing it, in the gaseous phase, towards the condenser 40, in which the refrigerant fluid R condenses giving up heat, and then towards the vaporizer 50, in which it vaporizes by absorbing heat, and then towards the absorption chamber 60 in which it recombines with the solvent S reconstituting the binary compound SR to finally return to the chamber of generation 30.

As mentioned, one of the peculiarities of the invention consists in the fact that the gases which pass in the duct 20 are the exhaust gases of the internal combustion engine 33 which is fed by the fuel present in the tank 29 of the vehicle. Finally, it should be noted that, since in the air conditioner according to the invention there are no moving electromechanical parts, it is particularly reliable and not subject to breakdowns.

The operation of the air conditioner 10 is clear and evident from what has been described.

In practice it has been found that the air conditioner for motor vehicles according to the present invention achieves the intended aim and objects since it allows the passenger compartment to be cooled and possibly heated by making use of the engine exhaust gases.

Another advantage of the air conditioner according to the invention consists in the fact that it has a lower environmental impact if compared to the known art.

A further advantage of the air conditioner according to the invention consists in the fact that it is quieter than in the known art.

Another advantage of the air conditioner according to the invention consists in the fact that it has limited consumption.

Another advantage of the air conditioner according to the invention consists in the fact that it is more reliable and less subject to breakdowns than the known art.

Another advantage of the air conditioner according to the invention consists in the fact that it is easy to manufacture and economically competitive if compared to the known art.

The air conditioner for motor vehicles thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the attached claims.

Furthermore, all the details can be replaced by other technically equivalent elements.

In practice, the materials employed, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.

Claims (8)

1. Air conditioning system (10) for the air conditioning of the passenger compartment (A) of a vehicle of the type equipped with an internal combustion engine, characterized in that it comprises an absorption refrigeration unit (100) which in turn comprises: a refrigeration circuit (90) adapted to contain a fluid compound (SR) and comprising at least one evaporator (50) placed in thermal communication with the passenger compartment (A) of the vehicle and - a duct (20) adapted to convey the exhaust gases of said internal combustion engine, said duct (20) being placed in thermal communication with said refrigeration circuit (90), the exhaust gases flowing within said duct heating said compound fluid (SR) in such a way as to evaporate at least a part of it making it circulate in the refrigeration circuit (90) towards said evaporator (50). 2. Air conditioner (10) according to claim 1, characterized in that said fluid compound (SR) is a binary compound (SR) comprising a refrigerant fluid (R) and a solvent (S). 3. Air conditioner (10) according to claim 2, characterized in that said binary compound (SR) is one of the following: lithium bromide and water (H20-BrLi), in which water (H20) is the refrigerant fluid ( R) and lithium bromide (Brìi) is the solvent (S), ammonia and water (NH3-H20), in which ammonia (NH3) is the refrigerant fluid (R) and water (H20) is the solvent (S). 4. Air conditioner (10) according to claim 2 or 3, characterized in that said refrigeration circuit (90) comprises a generation chamber (30) in thermal communication with said duct (20) and in fluid communication with a condenser ( 40), which condenser (40) is in thermal communication with the external environment (E) and in fluid communication with said evaporator (50), which evaporator (50) is in fluid communication with an absorption chamber ( 60), which absorption chamber (60) is in turn in fluid communication with said generation chamber (30); said refrigeration circuit (90) being configurable at least in a cooling configuration for cooling the passenger compartment (A), in which: the gases flowing into the burner (20) heating said binary compound (SR) in the generation chamber (30 ) to evaporate at least part of the refrigerant fluid (R) by separating it from the solvent (S) and pushing it, in the gaseous phase, towards the condenser (40), in which said refrigerant fluid (R) condenses, releasing heat to the external environment (E), and then towards the vaporizer (50), in which it vaporizes by absorbing heat from the passenger compartment (A), and then towards the absorption chamber (60) in which it recombines with the solvent (S), reconstituting said binary compound (SR); said absorption chamber (60) being connected to the generation chamber (30) by means of a delivery duct (61) for the passage of the solvent (S) from the generation chamber (30) to the absorption chamber (60) and a return (62) for the passage of the binary compound (SR) from the absorption chamber (60) to the generation chamber (30). 5. Air conditioner (10) according to one or more of the preceding claims, characterized in that said evaporator (50) and / or said condenser (40) is placed in thermal communication with a heat-carrying liquid which in turn is placed in thermal communication with the passenger compartment (A). 6. Air conditioner (10) according to claim 4 or 5, characterized in that said refrigeration circuit (90) can also be configured in a heating configuration for heating the passenger compartment (A), in which said condenser (40) is thermal communication with the passenger compartment (A) and said evaporator (50) is placed in thermal communication with the external environment (E) so that heat is transferred from said refrigerant fluid (R) to the passenger compartment (A) and absorbed heat from the external environment (E). 7. Method for air conditioning the passenger compartment (A) of a vehicle of the type equipped with an internal combustion engine (33), characterized in that it comprises at least the steps of: a) taking exhaust gases from said internal combustion engine; b) using the heat of said exhaust gases to heat a binary compound (SR) comprising a solvent (S) and a refrigerant fluid (R), by evaporating at least part of said refrigerant fluid (R); c) let said refrigerant fluid (R) pass first through a condenser (40) making it liquefy and then into an evaporator (50) in which it is evaporated at low pressure, cooling the surrounding air and / or a heat-carrying fluid which cools the surrounding air; d) convey the air cooled in the previous step into the passenger compartment (A) of the vehicle. 8. Motor vehicle characterized in that it comprises an air conditioner (10) according to one or more of claims 1 to 6.