METHOD FOR HEATING A HOUSING CONTAINING AT LEAST ONE FUNCTIONAL BODY

Abstract

Disclosed is a method for heating a housing containing at least one functional member, the housing including: at least one wall shared with a reservoir intended to receive a liquid; and at least one wall provided with an orifice leading to the outside and closed by a pressure equalizing membrane porous to water vapor and impermeable to liquid water. The method is notable in that the interior volume of the housing is heated in at least one of the following situations: when the reservoir is subjected to a drop in temperature other than a drop in temperature likely to cause the liquid to freeze; each time a vehicle equipped with this housing is started; and when thermal conditions capable of producing condensates are detected in the interior volume of the housing, closed by the membrane.

Claims

1. A method for heating a housing containing at least one functional member, said housing comprising: at least one wall shared with a reservoir intended to receive a liquid, and at least one wall provided with an orifice leading to the outside and closed by a pressure equalizing membrane porous to water vapor and impermeable to liquid water, the interior volume of said housing in at least one of the following situations: when said reservoir is subjected to a drop in temperature other than a drop in temperature likely to cause said liquid to freeze, each time a vehicle equipped with this housing is started, when thermal conditions capable of producing condensates are detected in the interior volume of said housing, closed by said membrane.

2. The method as claimed in claim 1, wherein the interior volume of said housing is heated when said rcservoir is filled with said liquid, or after having detected this filling.

3. The method as claimed in claim 1, wherein the interior volume of said housing is heated when said reservoir and said housing are at least partially submerged during fording.

4. The method as claimed in claim 1, wherein the interior volume of said housing is heated by means of elements secured to said shared wall and provided to ensure that said liquid melts.

5. The method as claimed in claim 1, wherein the interior volume of said housing is heated by means of a heat flow coming from the engine of a vehicle equipped with said reservoir.

6. The method as claimed in claim 1, wherein the heating of the interior volume of said housing is triggered on the basis of information supplied by a sensor selected from the group comprising a sensor for sensing the pressure, a sensor for sensing the temperature, a sensor for sensing the level inside said reservoir, an opening sensor for sensing the opening of the filling orifice of said reservoir.

7. The method as claimed in claim 1, wherein the interior volume of said housing is heated for at least 30 seconds and at most 2 hours, and so as to raise its absolute temperature from 30K to 100K.

8. The method as claimed in claim 1, applied to a housing integral with a reservoir of urea for reducing NOx emissions in a diesel engine.

9. The method as claimed in claim 1, applied to a housing integral with a reservoir of water for cooling a gasoline engine.

10. The method as claimed in claim 1, applied to a housing integral with a reservoir of fuel for supplying the hydrogen production device of a fuel-cell-powered engine.

11. A device for controlling the heating of the interior volume of said housing, wherein the device is programmed to implement the heating method as claimed in claim 1.

12. A non-transitory computer-readable medium on which is stored a computer program, which when executed by a computer in a device for controlling the heating of the interior volume of a housing, causes the computer to perform the method of claim 1.

13. The method as claimed in claim 2, wherein the interior volume of said housing is heated by means of elements secured to said shared wall and provided to ensure that said liquid melts.

14. The method as claimed in claim 3, wherein the interior volume of said housing is heated by means of elements secured to said shared wall and provided to ensure that said liquid melts.

15. The method as claimed in claim 2, wherein the interior volume of said housing is heated by means of a heat flow coming from the engine of a vehicle equipped with said reservoir.

16. The method as claimed in claim 3, wherein the interior volume of said housing is heated by means of a heat flow coming from the engine of a vehicle equipped with said reservoir.

17. The method as claimed in claim 4, wherein the interior volume of said housing is heated by means of a heat flow coming from the engine of a vehicle equipped with said reservoir.

18. The method as claimed in claim 2, wherein the heating of the interior volume of said housing is triggered on the basis of information supplied by a sensor selected from the group comprising a sensor for sensing the pressure, a sensor for sensing the temperature, a sensor for sensing the level inside said reservoir, an opening sensor for sensing the opening of the filling orifice of said reservoir.

19. The method as claimed in claim 3, wherein the heating of the interior volume of said housing is triggered on the basis of information supplied by a sensor selected from the group comprising a sensor for sensing the pressure, a sensor for sensing the temperature, a sensor for sensing the level inside said reservoir, an opening sensor for sensing the opening of the filling orifice of said reservoir.

20. The method as claimed in claim 4, wherein the heating of the interior volume of said housing is triggered on the basis of information supplied by a sensor selected from the group comprising a sensor for sensing the pressure, a sensor for sensing the temperature, a sensor for sensing the level inside said reservoir, an opening sensor for sensing the opening of the filling orifice of said reservoir.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features and advantages of the invention will become apparent on reading the following description, with reference to the appended figures, in which:

[0031] Fig. 1: shows a schematic section of a reservoir of liquid and its associated housing, to which the method according to the invention is applied;

[0032] Fig. 2: shows a detail view of the zone Z in FIG. 1, when the reservoir is being filled with a liquid, causing condensation to form on the inside of the wall of the housing;

[0033] Fig. 3: shows a detail view of the zone Z in FIG. 1, once the heating elements arranged on the inside of the wall of the housing have been activated.

[0034] For greater clarity, identical or similar elements are denoted by identical or similar reference signs throughout the figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Reference is now made to FIG. 1, in which there is shown a reservoir 1, provided with a stopper 3, which is able to contain a liquid 5 such as an aqueous solution of urea.

[0036] A housing 7 overlapping the interior volume of the reservoir 1 is provided, such that this housing and this reservoir have a shared wall 9.

[0037] The reservoir 1 and the housing 7 may both be formed, for example, from high density polyethylene (HDPE).

[0038] The housing 7 contains various members which are not shown, such as sensors for sensing the level and temperature of the liquid 5, a sensor for sensing the pressure inside the reservoir 1, a pump, an electrically controlled valve, etc.

[0039] A hydraulic connector 11 makes it possible to pump the liquid 5 located inside the reservoir 1 in the direction of the point of use.

[0040] The aqueous urea solution 5 is suitable for reducing NOx emissions in the exhaust gases of a diesel engine: in the prior art, reference is made to the SRC process: Selective Catalyst Reduction.

[0041] Of course, the present invention is not limited to this type of application, and the method of the invention can be used if the liquid 5 is water in order to cool a gasoline engine to comply with the new anti-pollution standards, according to which it is no longer permitted to cool a gasoline engine by injecting excess fuel for the sole purpose of cooling the engine, or if this liquid is a mixture of water and alcohol (for example ethanol) for a hydrogen-cell-powered engine.

[0042] As is known per se, in its lower part, that is to say in its part intended to be located toward the bottom when the assembly of reservoir 1 and housing 7 is in use on board a vehicle, the housing 7 has an outer wall having an orifice provided with a breathable membrane 13.

[0043] As is known per se, such a membrane 13 makes it possible for water vapor to circulate into or out of the housing 7, but prevents the passage of liquid water. This membrane equalizes the total and partial pressures of the gases on either side of the wall of the housing.

[0044] Reference will now be made more particularly to FIG. 2.

[0045] As can be seen in this figure, the housing 7 has, on the inside of its wall 9, heating elements 15, which may be formed for example by self-regulating heating ceramics, often denoted in the literature as “PTC elements”.

[0046] FIG. 2 shows the reservoir 1 and the housing 7 when the reservoir 1 is being filled with liquid 5.

[0047] During this filling operation, the liquid 5 suddenly cools the wall 9, thereby having the effect of suddenly cooling the humid air present inside the housing 7, consequently reducing the saturation vapor pressure, causing the condensation of the excess water vapor and the appearance of moisture in the form of condensate on the inner face of the wall 9.

[0048] This condensation is detrimental to all of the members located inside the housing 7, running the risk of causing corrosion phenomena in these members.

[0049] To avoid this drawback, the method according to the invention consists in activating the heating elements 15, such that they emit heat (symbolized by the arrows 20) increasing the saturation vapor pressure and evaporating the water droplets 17 appearing on the inside of the wall 9.

[0050] Thus, the partial pressure of the water vapor inside the housing 7, and also the overall pressure of the air inside this housing, increase, such that the air passes through the membrane 13 out of the housing 7, as is indicated by the arrow 21.

[0051] It is thus possible to quickly reduce the phenomenon of condensation inside the housing 7, and thus protect the members located inside this housing against phenomena of corrosion or electrical insulation fault.

[0052] In practice, it was possible to verify that activation of the heating elements 15 for a few minutes was enough to significantly reduce the humidity inside the housing 7.

[0053] It is also possible to envisage activating the heating elements 15 periodically, in order to evaporate the residual condensates in an already dry environment and therefore to further reduce the humidity.

[0054] More specifically, a temperature increase of 60K makes it possible typically to discharge 20% of the water vapor volume to the outside through the breathable wall 13, and a temperature increase of 80K makes it possible typically to discharge 30% of this water vapor volume.

[0055] It will be noted that the heating elements 15 already exist inside the housing 7, that is to say that they are used in any case for an antifreeze (melting) function of the solidified product 5.

[0056] Thus, the present invention in no way requires the installation of new heating elements inside the housing 7, but consists in an activation of these elements outside of their previously known operating circumstances.

[0057] Thus, the present invention can be implemented without new equipment, and therefore without considerable additional cost, on existing vehicles.

[0058] In the above text, the invention has been illustrated in the case in which the rapid cooling of the wall 9 of the housing 7 is caused by the reservoir 1 being filled with the liquid 5.

[0059] It will however be noted that the method according to the invention can be implemented in other types of circumstances, for example when the housing 7 is suddenly cooled during fording of the vehicle, this cooling then being caused by the body of water through which the vehicle passes: this is because the reservoir 1 and its associated housing 7 are frequently installed in the floor of the vehicle, that is to say in a zone exposed during fording.

[0060] Of course, the invention is described in the above text by way of example. It is understood that those skilled in the art are able to produce different variant embodiments of the invention without thereby departing from the scope of the invention.