FR3093957A1 - FLUID HEATING DEVICE FOR AUTOMOTIVE VEHICLES - Google Patents

Abstract

The subject of the invention is a device for heating a fluid (F) for a motor vehicle, comprising at least a first heating block (2) delimiting a zone for heating said fluid (11) and comprising a means of circulation of the fluid in said first heating block (2), the fluid circulating means (12) being internal to the heating zone (11).

Description

FLUID HEATER DEVICE FOR MOTOR VEHICLE

The subject of the invention is a device for heating a fluid for a motor vehicle, of the so-called high voltage type.

In known manner, such a device comprises a heating block disposed in a housing, an outer surface of the heating block being spaced from an internal wall of the housing so as to form a passage for the fluid, which is then heated in contact with the heating block.

The heating block is powered by an electrical voltage generally greater than 40V, for example 48V, preferably greater than 60V, which ensures efficient heating of the heat transfer fluid, itself preferably intended for a heating, ventilation and/or heating system. air conditioning of a motor vehicle cabin, or to a thermal management system of a battery of an electric or hybrid vehicle.

Nevertheless, such a known device has the drawback that the external surface of the heating block can reach temperatures above 100° C., which causes the layer of fluid in direct contact with the surface to boil. The fluid which circulates in the device then comprises a liquid and gaseous mixture which can alter the operation of the associated heating system and present a risk of ignition of the gases, in particular of explosion, and of a rise in pressure of the fluid.

The object of the invention is to remedy this drawback.

To this end, the subject of the invention is a device for heating a fluid for a motor vehicle comprising at least a first heating block delimiting a zone for heating said fluid and comprising a means for circulating the fluid in said first heating block, the fluid circulation means being internal to the heating zone.

The heating device according to the present invention ensures, thanks to the means for circulating fluid internal to the heating zone, the displacement of the fluid in the heating block, which makes it possible to drastically reduce the risk of overheating, while being compact and simple to install in a motor vehicle, the often strong installation constraints of which must be respected.

According to another characteristic of the invention, the means for circulating fluid is an endless screw.

According to another characteristic of the invention, the first heating block comprises a hollow heating element defining a fluid flow passage, the endless screw extending in the fluid flow passage.

According to another characteristic of the invention, the hollow heating element is of tubular shape directed along a longitudinal axis, the endless screw extending longitudinally along the longitudinal axis of the heating element.

According to another characteristic of the invention, the device comprises a second heating block delimiting a fluid heating zone and comprising means for circulating the fluid in said second heating block, said means for circulating fluid being internal to the heating zone of the second heating block.

According to another characteristic of the invention, the device comprises a fluid outlet outside the device (that is to say towards the outside of the device) common to the first and to the second heating blocks.

According to another characteristic of the invention, the device comprises a first fluid outlet and a second fluid outlet dedicated respectively to the first heating block and to the second heating block.

According to another characteristic of the invention, the device comprises a motor or actuator for controlling each means for circulating fluid.

According to another characteristic of the invention, the device comprises a printed circuit board for controlling each heating block, said board also being configured to electrically supply each control motor.

According to another characteristic of the invention, each motor comprises a winding integral with the printed circuit board, and a set of magnets integral in rotation with the means for circulating the associated fluid.

The invention also relates to a heating, ventilation and/or air conditioning system for a motor vehicle, comprising a heating device as described previously.

The invention also relates to a thermal management system for a battery for an electric motor vehicle, comprising a heating device as described previously.

Other characteristics, details and advantages of the invention will appear on reading the detailed description below, and on analyzing the appended drawings, in which:

Fig. 1

illustrates a perspective view of a heating device according to the present invention;

Fig. 2

illustrates a longitudinal view of the device of Figure 1.

Fig. 3

illustrates a heating device according to another alternative embodiment connected to a heat exchanger.

Fig. 4

illustrates a heating device according to another alternative embodiment connected to two heat exchangers.

As illustrated in the figures, the subject of the invention is a heating device, referenced 1 in the figures. Device 1 heats a liquid fluid, such as water, or glycol water, referenced F.

The device 1 is preferably associated with a heating, ventilation and/or air conditioning system for a motor vehicle passenger compartment and/or with a battery thermal management system for an electric or hybrid vehicle.

The device 1 is of the high voltage type, that is to say it is powered by a voltage greater than 40V, for example 48V, or 60V up to 800-1000V .

The device 1 comprises at least a first heating block. In the embodiments illustrated, the device comprises a first and a second heating block, referenced 2 and 3 respectively in the figures.

As can be seen from the figures, the device 1 also comprises a casing 4 for housing the heating blocks 2, 3. The casing 4 is provided with an inlet 7 for the fluid F in the device 1, forming the bottom of the casing 4 as well as with one or two fluid outlets 8 out of device 1, opposite to inlet 7.

As visible in the figures, each of the heating blocks 2, 3 comprises a hollow heating element 10 and delimiting a fluid circulation passage 11. In the figures, each heating element 10 is a cylindrical heating tube comprising a heating resistor of the type screen-printed track (the screen-printed track being arranged outside the heating tube while the fluid circulates inside this same heating tube). Thus, the passage 11 forms a heating zone of the associated heating block, 2, 3.

Thanks to this configuration, the heat produced by the resistance is directly transmitted to the fluid to be heated through the wall of the corresponding heating tube 10, which minimizes heat losses and reduces the thermal inertia of the device, the fluid being able to be heated quickly.

Passage 11 forms a heating zone of electric heating device 1.

As also emerges from FIGS. 1 and 2, each heating block 2, 3 comprises an associated fluid circulation means 12. In the illustrated embodiments, the circulation means is an endless screw.

Each endless screw 12 comprises a shaft 13 on which is mounted a helical spline 14 and extending along a longitudinal axis A, A' parallel to a longitudinal axis L, L' of the associated heating element 10. In Figure 2, the axes A and A' coincide respectively with the axes L and L'.

Each endless screw 12 is rotatable around its longitudinal axis L, L′, which drives the fluid F in a movement from bottom to top, from the inlet 7 to one of the outlets 8.

The endless screws 12 are internal to the associated heating zone 11, which ensures the compactness of the cooling device 1.

As also emerges from the figures, each heating block 2, 3 comprises an electric motor 15 to control the movement of the shaft 13 of the endless screw 12. The electric motor is advantageously of the brushless or stepper type.

Each of the motors 15 comprises on the one hand a set of magnets 16 and on the other hand windings 17 to set the magnets 16 in motion. The magnets 16 are mounted on one end 18 of the shaft 13, thereby driving the rotation of the shaft 13 around its longitudinal axis L, L′.

As also visible in FIG. 2, the device 1 comprises a printed circuit board 19. The printed circuit board 19 makes it possible to control the heating power generated by the heating elements 10. The printed circuit board 19 also makes it possible to supply and electrically drive the windings 17 of the motors 15. It is noted that advantageously, the windings 17 are soldered and/or connected to the printed circuit board 19.

The configuration according to the present invention makes it possible to best adjust the rotation of the endless screws 12 taking into account the flow rate and the temperature of the fluid and/or according to the power and/or heating temperature of each heating element 10, in order to avoid any risk of overheating the heating elements and to limit the risk of the fluid boiling.

According to the variant of Figure 1, the heating device 1 comprises an input 7 and a single output 8.

According to the variant of Figure 3, the heating device 1 comprises an inlet 7 and two outlets 8, 8 'of the heat transfer fluid. Each of the outputs 8, 8' is connected to a separate part 21, 21' of a heat exchanger 20. Thus, the first heating block 2 is dedicated to part 21 of the exchanger 20 while the second heating block heater 3 is dedicated to part 21' of exchanger 20.

According to the variant of Figure 4, the heating device 1 comprises an inlet 7 and two outlets 8, 8 'of the heat transfer fluid. Each of the outlets 8, 8' is connected to a respective heat exchanger 20, 20'. Thus, the first heating block 2 is dedicated to the exchanger 20 while the second heating block 3 is dedicated to the exchanger 20'. Advantageously, one of the exchangers 20, 20' is part of a heating, ventilation and/or air conditioning system for the passenger compartment of the motor vehicle, while the other of the exchangers 20, 20' is part of a thermal management of a battery of an electric or hybrid vehicle.

According to these last two variants, the control of the endless screw 12 and of the heating element 10 of the first block 2 is advantageously independent of the control of the endless screw 12 and of the heating element 10 of the second heating block 3.

As already apparent from the preceding description, the heating device 1 according to the present invention ensures a movement from bottom to top, from the input 7 to the outputs 8; 8', heat transfer fluid while being compact, easy to install, adjustable to the power of the heating elements, minimizing the risk of boiling and which can be adapted to different heat exchangers.

It is noted that, of course, the invention is not limited to the illustrated embodiments. For example, heater blocks 2 and 3 are identical in the figures but, nevertheless, depending on the heating needs of the vehicle, heater blocks 2 and 3 may differ from each other. In particular, the endless screws may have different dimensions and/or rotational speeds.

Claims (10)

Device for heating a fluid (F), preferably a liquid fluid, for a motor vehicle, comprising at least a first heating block (2) delimiting a zone for heating said fluid (11) and comprising circulation of the fluid in said first heating block (2), the fluid circulation means (12) being internal to the heating zone (11). Heating device according to the preceding claim, in which the fluid circulating means (12) is a worm. A heating device according to the preceding claim, wherein the first heating block (2) comprises a hollow heating element (10) delimiting a fluid flow passage (11), the worm extending into the fluid flow passage. fluid flow (11). Heating device according to the preceding claim, in which the hollow heating element (10) is of tubular shape directed along a longitudinal axis (L), the worm (12) extending longitudinally along the longitudinal axis (L) of the heating element (10). Heating device according to one of the preceding claims, comprising a second heating block (3) delimiting a heating zone of the fluid (11) and comprising means for circulating the fluid (12) in said second heating block ( 3), said means for circulating fluid (12) being internal to the heating zone (11) of the second heating block (3). Heating device according to the preceding claim, comprising a fluid outlet outside the device (8) common to the first and to the second heating blocks (2, 3). Heating device according to claim 5, comprising a first fluid outlet (8) and a second fluid outlet (8 ’) dedicated respectively to the first heating block (2) and to the second heating block (3). Device according to one of the preceding claims, comprising a motor or actuator (15) for controlling each fluid circulation means (12). Heating device according to the preceding claim, comprising a printed circuit board (19) for controlling each heating block, said board (19) also being configured to supply electric power to each control motor (15). Heating device according to the preceding claim, in which each motor (15) comprises a coil (17) integral with the printed circuit board (19), and a set of magnets (16) integral in rotation with the circulation means. associated fluid (12).
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