FR2850060A1 - Passenger compartment temperature control device for motor vehicle, has heat exchange unit with independent temperature control casings and flow control valves connected to respective semi-heat exchangers - Google Patents

Abstract

The device has a reversible refrigerating loop (1) and a loop (9) provided with a heat exchanger (4) traversed by refrigerant and coolant fluids. A heat exchange unit is traversed by the coolant fluid and air flow intended to heat or cool passenger compartment. The heat exchange unit has independent temperature control casings (17a-17c), and flow control valves (24a-24c, 25a-25c) connected to respective semi-heat exchangers. An Independent claim is also included for a method for controlling temperature in a passenger compartment of a motor vehicle.

Description

Device and method for thermal regulation of the passenger compartment of a vehicle

automotive

  The present invention relates to a device and a method for thermal regulation of the passenger compartment of a motor vehicle.

  Devices of this type are known comprising a reversible refrigeration loop with circulation of a refrigerant and a secondary loop provided with a heat exchanger through which the refrigerant and a heat transfer fluid pass. Depending on the direction of circulation of the refrigerant in the refrigeration loop, this provides heating or cooling of the heat transfer fluid, the refrigeration loop functioning either as a refrigeration system generating frigories, or as a heat pump. The heat transfer fluid, which may for example be brine, can transfer calories or frigories into the passenger compartment of the vehicle via an air flow which passes through a heat exchanger also traversed by the fluid. coolant.

  We know, for example from French patent application 2,780,490, a system for adjusting the temperature in the passenger compartment of a vehicle comprising a secondary loop associated with two heat exchangers, one of which is placed in the passenger compartment. and the other outside.

  Also known from French patent applications 2 808 740, 2 808 741 and 2 808 742 a device for thermal regulation of the passenger compartment of a motor vehicle comprising an exchanger for the production of cold and an exchanger for the production of heat, both arranged in the passenger compartment of the vehicle, all the other elements of the system being mounted in the engine compartment. These devices have the disadvantage of being bulky.

  French patent application 2 804 068 describes a device for heating and air conditioning the passenger compartment of a vehicle which comprises a single exchanger placed in the passenger compartment and which can alternatively provide air conditioning or heating. Such a device, if it has the advantage of greater compactness, does not make it possible to avoid the phenomenon of instantaneous fogging which occurs when the same exchanger, over a short period of time, is used successively to produce cold then to produce hot.

  In this case, in fact, the exchanger having first operated in air conditioning mode is charged with humidity. When the hot heat transfer fluid circulates in this same exchanger, the moisture vaporizes, causing the instantaneous appearance of mist in the passenger compartment.

  Furthermore, in most of the known thermal regulation devices for the passenger compartment of a motor vehicle, it is necessary to provide a mixing and distribution box for the air which must be sent to different places in the passenger compartment of the vehicle 15 after having been heated or cooled in contact with a heat exchanger. Such a mixing and distribution box equipped with a plurality of mixing and distribution flaps is generally disposed in the vicinity of the engine compartment and has the drawback of increasing the size of the entire thermal regulation system 20 and cause significant pressure drops in the air supply lines to the appropriate places in the vehicle cabin.

  The object of the present invention is to allow the thermal regulation of the passenger compartment of a motor vehicle in a more compact manner than by the devices of the prior art while allowing better comfort throughout the passenger compartment. .

  The invention also relates to a thermal regulation device in which the problems caused by the phenomenon of instantaneous fogging in the passenger compartment are resolved.

  The device according to the invention for the thermal regulation of the passenger compartment of a motor vehicle, comprises a reversible refrigeration loop with circulation of a refrigerant and a secondary loop provided with a heat exchanger through which the refrigerant and by a heat transfer fluid. A heat exchange means is traversed by the heat transfer fluid and by an air flow intended to heat or cool the passenger compartment of the vehicle. The heat exchange means 5 comprises at least two independent thermal control boxes, each comprising two half heat exchangers, an air supply means, air distribution flaps and two connected flow control valves respectively to the two half-exchangers.

  It thus becomes possible to provide several thermal control boxes of reduced size, each being arranged in the passenger compartment near the place where the calories or the frigories must be brought. In particular, a central space-saving box can be provided in the vicinity of the dashboard of the vehicle so as to demist the windshield and possibly to supply central air vents. Each half-exchanger, intended for the thermal management of an area of the passenger compartment, can be of smaller size than a conventional exchanger intended for the thermal management of the entire passenger compartment.

  The different boxes are each connected to the refrigeration loop by flexible pipes conveying the heat transfer fluid. These pipes, with a diameter of for example 20 mm, which reduces the pressure losses, are compact and easy to insulate thermally. The pressure drops in the air lines are also reduced by this exploded arrangement of the individual housings.

  Each unit can be regulated in flow, temperature and air distribution independently of the other units, thereby ensuring comfort adapted to each specific area of the passenger compartment.

  One can for example provide a central box for demisting and two side boxes for the comfort of the driver and front passenger. Other additional side boxes can be added if one wishes to also ensure the comfort, for example, of the rear passengers. Just add individual boxes to ensure individual comfort.

  Preferably, the two half heat exchangers are mounted in series in the air flow and in parallel on the heat transfer fluid flow.

  Each half-exchanger can be connected alternately or simultaneously to the secondary loop and / or to a thermal regulation circuit of the vehicle drive motor depending on the control of the flow control valves placed respectively upstream and downstream of the different thermal regulation boxes.

  A control unit is advantageously provided for controlling the flow control valves according to the environmental conditions.

  In an advantageous embodiment, the thermal regulation device comprises means for detecting the operation of each half-exchanger and timing in order to prevent operation in heating mode of a half-exchanger before the expiration of a period of time. predetermined after operating in air conditioning mode of the same half-exchanger.

  This avoids the instantaneous phenomenon of fogging in the passenger compartment, which occurs when the same heat exchanger is used to produce heat immediately after being used to produce cold.

  In a preferred embodiment, the refrigeration loop is entirely housed in the engine compartment of the vehicle.

  The thermal regulation method according to the invention, for the passenger compartment of a motor vehicle implements a means of heat exchange traversed by a heat transfer fluid and by an air flow to heat or cool the passenger compartment of the vehicle , and plans to independently regulate the flow of heat transfer fluid passing in parallel at least two half heat exchangers through which the air flow is forced.

  Preferably, the mode of operation of each half-exchanger and the duration of operation are detected and operation in heating mode of a half-exchanger is prevented before expiration of a predetermined period of time after operation in air conditioning mode of the same half exchanger, so as to avoid the phenomenon of instant fogging.

  The invention will be better understood on studying the description of the two embodiments described by way of non-limiting examples and illustrated by the appended drawings in which: - Figure 1 illustrates a first embodiment; and - Figure 2 illustrates a second embodiment.

  In FIGS. 1 and 2 are schematically represented the main elements of two embodiments of a thermal regulation device according to the invention. The engine compartment of the motor vehicle is designated by the letter M while the passenger compartment is designated by the letter H. The long dashed line represents the border between the engine compartment and the passenger compartment of the vehicle.

  Referring first to Figure 1, in the engine compartment, is installed the refrigeration loop 1, the circulation of refrigerant is symbolized by a dotted line. The refrigeration loop 1 comprises a high pressure heat exchanger 2, an expansion element 3, a low pressure heat exchanger 4 and a compressor 5. A fan 6 is capable of bringing an air flow over the heat exchanger. high pressure heat 2. The direction of circulation of the refrigerant in the refrigeration loop can be reversed by means of a valve 7, the inversion being symbolized by the dashed cycle 8. Of course, any other element could also be used. capable of modifying the direction of circulation of the refrigerant.

  In refrigeration mode, the high pressure exchanger 2, playing the role of condenser, releases calories to the outside air.

  The low pressure exchanger 4 which acts as an evaporator allows the cooling of a heat transfer fluid which circulates in a secondary loop 5 illustrated in dashes and which comprises a circulation pump 10.

  In heat pump mode, the direction of flow of the refrigerant is reversed so that the high pressure exchanger 4 acts as a condenser while the low pressure heat exchanger 6 acts as an evaporator. The heat exchanger 4 then makes it possible to heat the heat transfer fluid which flows in the secondary loop 9.

  The secondary loop 9 is coupled to the cooling circuit 11 of the engine 12 of the motor vehicle. This cooling circuit 15 It includes a radiator 13 coupled to the high pressure heat exchanger 2 with regard to the flow of the air flow caused by the fan 6. A circulation pump 14 causes the circulation of heat transfer fluid to through the engine 12 then through the radiator 13. A branch branch 15 is also provided with a three-way valve i5a to isolate the engine 12 from the radiator 13 during the cold start phase. A two-way valve 16 is mounted in the circuit II to isolate the engine 12 from the branches of the cooling circuit 11 which convey calories in the passenger compartment H, as explained below.

  It will be noted that the refrigeration loop 1 can be produced in a particularly compact manner and entirely housed in the engine compartment M which also includes the low pressure heat exchanger 4 and the cooling loop 11 of the engine 12.

  The calories or the frigories are brought into the passenger compartment H 30 via several small-sized boxes referenced respectively 17a, 17b and 17c and housed in the passenger compartment H of the vehicle.

  Each of these housings 17a, 17b and 17c comprises two half heat exchangers 18a, 19a; 18b, 19b; 18c, 19c. An air supply means, such as a fan or an air blower 20a, 20b, 20c brings an air flow which passes in series through the two half heat exchangers 18a, 19a; 18b, 19b and 18c, 19c. These air flows 5 have been identified in the figure by the arrows 21. In each housing 17a, 17b, 17c, the two half-exchangers 18a, 19a; 18b, 19b and 18c, 19c are mounted in parallel on the heat transfer fluid circuit and connected on one side to a pipe 22 and on the other side to a return pipe 23. Controlled valves are provided at the inlet of each 10 of the semi-exchangers and referenced 24a, 25a; 24b, 25b and 24c, 25e; so as to individually control the flow of fluid flowing in each of the half-exchangers.

  The housing 17a has the particularity of receiving on the half-exchanger 18a the heat transfer fluid coming directly from the secondary loop 15 9. An additional valve 26 makes it possible to isolate the flow of heat-transfer fluid coming from the loop 9 and the other half-exchanger 19a as well as the two housings 17b and 17c. In the open position of the valve 26, the half-exchanger 19a is supplied with heat transfer fluid from the secondary loop 9 and the two housings 17b and 17c both receive the heat transfer fluid from the secondary loop 9.

  A three-way valve 27 placed in the engine compartment also makes it possible to isolate the secondary loop 9 from the cooling loop 11 of the vehicle engine.

  A control unit not shown in the figure makes it possible to control the various flow control valves 24a, 25a; 24b, 25b; and 24c, 25c; as well as the valves 26 and 27 depending on the environmental conditions and the thermal regulation sought for the passenger compartment.

  The box 17a can constitute a particularly compact central box placed in the vicinity of the dashboard of the vehicle, allowing both the demisting of the windshield of the vehicle and the possible supply of hot or cold air to central ventilators not shown on the figure.

  To this end, the central box 17a like the two boxes 17b and 17c includes air distribution flaps not shown in the figure.

  It is understood that such an architecture, using a plurality of independent thermal regulation boxes allows great modularity depending on the range of the vehicle and the desired service. In all cases, it is conceivable to use a central box 10 such as the box 17a and a second cabin box 17b and then to add other side boxes such as the box 17c according to the wishes and range of the vehicle. or other identical boxes to provide individualized comfort at different points in the vehicle cabin.

  Means for detecting the operation of each half-exchanger in each housing 17a, 17b, 17c are also provided but have not been shown in the figure. These means also make it possible to exercise a time delay on the control of the various distribution valves 24a, 25a; 24b, 25b; and 24c, 25c; in order to prevent the occurrence of the instant fogging phenomenon.

  To this end, if the first half-exchanger such as the half-exchanger 18a of the housing 17a has been used in air conditioning mode, its operation in heating mode will be prohibited for a certain time. For this, the positioning of the valve 24a will be such that the exchanger 18a which has released frigories and which now has retained the humidity of the air, does not receive the calories coming from the circuit 11 for cooling the engine or the secondary loop 9 of the refrigeration circuit 1 operating in heat pump mode. The heating produced by the housing 17a will then be ensured only by the second half-exchanger 19a which has not been used in refrigeration mode immediately before, the valve 25a being controlled so as to allow the passage of the heat-transfer fluid through this half -exchanger 19a. This operation will continue for a certain time until the humidity of the first exchanger 18a is slowly removed by the passage of air. After a predetermined time, the valve 24a can again be placed in the open position so as to allow the operation of the half-exchanger 18a in heating mode.

  The position of the various control valves 24a, 25a; 24b, 25b; and 24c, 25c; also allows regulation of the flow rate of the heat transfer fluid 10 or of the temperature of the exchangers of the various housings. The use of two half-exchangers in each of the housings 17a, 17b, 17c makes it possible to produce particularly compact housings since they no longer include a complete exchanger dedicated solely to the production of cold and a complete exchanger dedicated solely to the production heat. Indeed, the two half exchangers can be used simultaneously for the production of cold or hot. In addition, the temperature is adjusted by regulating the flow rate and / or the temperature of the heat transfer fluid, which makes it possible to eliminate the air mixing chamber and the mixing flap usually used in thermal regulation devices. of known type.

  For example, we can control the different control valves as follows: Situation 1: very hot environment (30 to 45 'C) The two half-exchangers of each box 17a, 17b, 17c produce cold to obtain the maximum cold power in the passenger compartment. The frigories come from the secondary loop 9, the coolant flowing through the valve 26 which is in the open position in the pipe 22. The return of the coolant 30 is done through the pipe 23 and the valve 27 as far as in the heat exchanger 4. The valve 16 is closed.

  Situation 2: hot environment (15 to 30 'C) The power of the refrigeration loop required is lower and only the first half-exchanger 18a, 18b and 18c of the various housings 17a, 17b, 17c is switched on, in order to optimize the 5 operation of the refrigeration loop. In other words, the valves 25a, 25b, 25c and 16 are placed in the closed position. As before, the heat transfer fluid coming from the secondary loop 9 passes through the valve 26 in the pipe 22 and returns through the pipe 23 and the valve 27 in the heat exchanger 4. 10 The second half-exchangers 19a , 19b, 19c therefore remain inactive.

  Situation 3: temperate environment (00C at 15 'C): To avoid the phenomenon of instantaneous fogging in heating mode, at least the first half-exchanger 18b, 18c of the housings 17b, 17c remains inactive if it has been used in the preceding phases 15 for cooling the air and the second exchanger 19a, 19b, 19c is used to heat the passenger compartment either with the engine calories coming from the engine cooling circuit 11, or with the calories from the thermally linked secondary loop 9 to refrigeration loop 1 operating in heat pump mode. Optionally, the first half-exchanger 18a can continue to receive the frigories of the secondary loop 9 to dry the air. To thermally optimize the actuation of the vehicle, the second half-exchanger 19a, 19b, 19c receives the calories from the heat pump during the starting of the engine 12 via the valve 26 25 in the open position, the valve 16 being held closed. As soon as the motor 12 has reached the operating set temperature, the secondary loop 9 is isolated by means of the three-way valve 27 which authorizes a return to the motor 12, the valve 26 remaining closed. The calories coming from the cooling loop 11 30 pass into the second half-exchanger 19a, 19b, 19c by passing through the valve 16 then the line 22 before returning via the line 23 through the valve 27. The necessary heat is thus supplied to the passenger compartment without increasing consumption due to the operation of the refrigeration loop which is not used.

  Situation 4: very cold environment (O "C to -18 'C) The same strategy can be used as in the previous situation 5 by this time operating the refrigeration loop 1 with a heat pump. In this situation there is no no risk that the first exchanger 18a, 18b, 18c has previously been used to produce cold air, operation in air conditioning is prohibited below 0 'C. The second exchanger 19a, 19b, 19c and possibly the first exchanger 18a , 18b, 18c can therefore receive calories without the risk of instant fogging, in order to obtain the maximum heating power in the passenger compartment.

  Situation 5: demisting of the passenger compartment The frigories of the refrigeration loop 1 are transferred, via the secondary loop 9, to the first exchanger 18a to dry the air. Then, the second exchanger 19a charged with calories by the circulation of the heat transfer fluid which has been heated in the circuit 11 for cooling the engine, regulates the temperature of air 20 blown towards the passenger compartment.

  The embodiment illustrated in FIG. 2 in which the identical parts have the same references differs from the previous embodiment by the mounting, on each of the housings 17b and 17c of an additional two-way valve 26b, 26c at the inlet and d a three-way valve 28c and four-way valve 28b at the outlet. Thanks to this arrangement, it is possible to connect the half-exchangers 18b and 18c by a pipe 29 to the secondary loop 9, the return being made by a pipe 30.

  It is possible, in this alternative embodiment, to control the 30 different valves so as to allow demisting in several zones of the passenger compartment. The housings 17a, 17b, 17c are then connected in parallel to the secondary loop 9. The valves 26a, 26b and 26c are placed in the closed position so that the half-exchangers 18a, 18b and 18c are supplied by the secondary loop 9. The return of the fluid at the outlet of the half-exchangers 18b and 18c takes place by means of the valves 28b and 28c which make it possible to avoid mixing with the return fluid from the half-exchangers 19b and 19c. The three half-exchangers 19a, 19b and 19e are supplied by the engine cooling circuit II via the pipe 22, the return being carried out by the pipe 23 and the three-way valve 27.

  All of these operating strategies of the two half-exchangers in each of the individual housings are made possible by the arrangement of the various elements and the appropriate control of the various control valves. The invention also makes it possible to produce a central box such as the particularly compact box 17a, and the arrangement of side boxes such as the boxes 17b 15 or 17c, at the appropriate places in the passenger compartment of the vehicle. This gives a remarkable gain in efficiency because the source of calories and frigories is located closest to the passenger and the place where it should be used. In addition, the pressure drops on the air passing through the half-exchangers are greatly reduced.

  The air conditioning refrigeration loop 1 can be made more compact than in conventional devices and placed entirely inside the engine compartment M. This allows for more efficient maintenance, faster replacement of the refrigerant and better control of leaks. . This results in a significant advantage for the use of CO2 as a refrigerant or other refrigerants working at higher pressures, such as potentially explosive hydrocarbons.

  Thanks to the arrangement of the entire refrigeration loop inside the engine compartment, it avoids the circulation of refrigerant in the passenger compartment of the vehicle, which can be dangerous in the event of a leak.

  Thanks to the structure of the device according to the invention and to the thermal regulation method of the present invention, it is possible to use a reversible refrigerating loop in a heat pump without risking the appearance of the phenomenon of instantaneous formation of fogging and without it it is necessary to add an additional exchanger as may have been recommended. Lateral demisting of the vehicle windows can be ensured by individual lateral boxes suitably arranged and operating in heating mode or in demisting mode.

  Thanks to its modularity, the secondary loop used in the device of the present invention makes it possible to offer multi-zone comfort with individual adjustment in flow, temperature and air distribution. The power distribution permitted by the use of individual boxes allows these small-sized boxes to be installed inside the dashboard of the vehicle. The boxes are particularly small thanks to the elimination of the chamber and the mixing flap usually used.

  The method and the device of the invention allow the individual operation of each of the half-exchangers fitted to each individual housing and thus make it possible to optimize the consumption of the operation of the refrigeration loop. In addition, it becomes possible to prohibit the circulation of calories from the engine in the passenger compartment in air conditioning or heat pump operating mode, which allows a faster rise in the temperature of the engine cooling water. vehicle.

Claims (8)

  1. A device for thermal regulation of the passenger compartment of a motor vehicle comprising a reversible refrigerating loop (1) with circulation of a refrigerant and a secondary loop (9) provided with a heat exchanger (4) through which the refrigerant and a heat transfer fluid and a heat exchange means through which the heat transfer fluid and an air flow intended to heat or cool the passenger compartment of the vehicle, characterized in that the exchange means thermal comprises at least two independent thermal regulation boxes (17a, 17b, 17c), each comprising two half heat exchangers (18a, 19a; 18b, 19b; 18c, 19c), an air supply means (20a , 20b, 20c), air distribution flaps and two controlled valves (24a, 25a; 24b, 25b; 24c, 25c) flow control connected respectively to the two half-exchangers (18a, '19a; 18b; 19b ; 18c, 19c).   2. A thermal regulation device according to claim 1 characterized in that the two half heat exchangers (18a, 19a; 18b, 19b; 18c, 19c) are mounted in series in the air flow and in parallel on the heat transfer fluid flow.   3. A thermal regulation device according to one of claims 1 or 2 characterized in that each half-exchanger (18a, 19a; 18b, 19b; 18c, 19c) can be connected alternately or simultaneously to the secondary loop (9 ) and / or to a circuit (11) for thermal regulation of the vehicle drive motor as a function of the control of flow control valves (26a, 26b, 26c) placed upstream of the housings (17a, 17b, 17c ) and flow control valves (27, 28b, 28c) placed downstream of the housings (17a, 17b, 17c).   4. A thermal regulation device according to any one of the preceding claims, characterized in that a control unit is provided for controlling the flow control valves as a function of the environmental conditions.   5. A thermal regulation device according to claim 4 characterized in that it comprises means for detecting the operation of each half-exchanger and timing in order to prevent operation in heating mode of a half-exchanger 5 before expiration a predetermined period of time after operating in air conditioning mode of the same half-exchanger.   6. A thermal regulation device according to any one of the preceding claims, characterized in that the refrigeration loop (1) is entirely housed in the engine compartment (M) of the vehicle.   7. A method of thermal regulation of the passenger compartment of a motor vehicle using a reversible refrigerating loop (1) and a secondary loop (9) provided with a heat exchange means traversed by a heat transfer fluid and by a flow of air intended to heat or cool the passenger compartment of the vehicle, characterized in that at least two independent units are used and the flow of heat-transfer fluid passing in parallel through at least two half heat exchangers of each unit is independent through which the air flow is forced.   8. A method of thermal regulation according to claim 7 characterized by the fact that the operating mode of each half exchanger and the duration of operation are detected and that operation in heating mode of a half exchanger is prevented before expiration a predetermined period of time after operating in air conditioning mode of the same half-exchanger.