Air treatment system for a motor vehicle, which system is provided with a hepa filter

Abstract

The invention relates to an air treatment system (1) for a motor vehicle comprising an exterior air intake duct (2), a passenger compartment air recirculation duct (3), a distribution duct (4) housing a motor-fan unit (5) and a first air filter (6), a two-way circulation filtration duct (7) housing a second HEPA air filter (8) and two bypass ducts (9, 10), the system further comprising a first flap for controlling the air flow (11) arranged at the interface between the outlet of the intake duct, a first inlet / outlet of the filtration duct and the inlet of the first bypass duct; and a second flap for controlling the air flow (12) arranged at the interface between the outlet of the recirculation duct, the second inlet / outlet of the filtration duct and the inlet of the second bypass duct.

Description

Description Title of the invention: Air treatment system for a motor vehicle provided with a HEPA filter [Technical field] [1] The present invention claims priority from French application 2306877 filed on June 29, 2023, the content of which (text, drawings and claims) is incorporated herein by reference. [2] The present invention relates generally to air treatment systems within the passenger compartment of motor vehicles. [3] The invention relates in particular to such an air treatment system for a motor vehicle provided with a HEPA type air filter. [Earlier technique] [4] As is known, a motor vehicle includes an air treatment system within the passenger compartment of this vehicle in order to ensure passenger comfort. [5] Generally referred to by the acronym HVAC (for Heating, Ventilation and Air-Conditioning in English), such an air treatment system typically includes: - an external air intake duct whose inlet is fluidically connected to the exterior of the vehicle; - a passenger compartment air recirculation duct whose inlet is fluidically connected to the interior of the vehicle passenger compartment; and - a diffusion duct whose outlet is fluidically connected to the interior of the vehicle's passenger compartment. [6] The HVAC air treatment system also includes a motor-fan unit and at least one first air filter housed in the diffusion duct, these two elements generally being integrated into an HVAC module located under the dashboard of the vehicle. [7] Such an HVAC air treatment system further comprises an air flow control flap arranged at the interface between the outlet of the outside air intake duct, the outlet of the recirculation duct and the inlet of the diffusion duct. [8] This control flap is movable between an open position in which said exterior air intake and diffusion ducts are fluidically connected so that the pulsed air entering the passenger compartment comes only from outside the vehicle, and a closed position in which said recirculation and diffusion ducts are fluidically connected so that the pulsed air entering the passenger compartment is only recycled air. [9] The actuation of this air flow control flap can generally be controlled either manually by the driver or front passenger via mechanical or tactile control devices, or automatically via the HVAC air treatment system supervision module.

[0010] In order to improve the quality of the cabin air, it is also known, in particular from US 10525395 B2, to place a HEPA type air filter (for "High Efficiency Particulates Arresting" in English, translating into French as [filter] with high efficiency against airborne particles) in the exterior air intake duct.

[0011] Such a HEPA filter is capable of filtering at least 99.95% of fine particles, invisible to the naked eye, with a diameter greater than or equal to 0.3 micrometers (pm).

[0012] In order to compensate for the pressure losses generated by these HEPA filters, they must have relatively large surface dimensions which can reach or even exceed 30 dm 2 , so they must be installed in the vehicle's engine compartment outside the HVAC module due to lack of sufficient free space under the dashboard.

[0013] These significant pressure losses also lead to a significant increase in the electrical power absorbed by the motor-fan unit for a given air flow rate at the filter outlet.

[0014] This electrical power proves to be particularly important during the rapid cooling phases initiated, for example, when starting vehicles with a very high passenger compartment temperature resulting from prolonged exposure in summer to full sunlight.

[0015] During such a rapid cooling phase, the pressure losses caused by the HEPA filter (and which evolve according to the square of the air flow rate at the inlet of this filter) are in fact particularly significant since the motor-fan unit then operates at its maximum electrical power so that the air flow rate entering the passenger compartment is as high as possible (approximately 500 kg / h) so as to ensure rapid cooling of this passenger compartment.

[0016] It is therefore understandable that the installation of such a HEPA filter requires oversizing the motor-fan unit, the maximum operating power of which must be greater than that of a conventional motor-fan unit fitted to vehicles without this type of filter.

[0017] In addition to the additional cost and the increase in operating noise generated by this oversizing of the motor-fan unit, the major disadvantage of installing such a HEPA filter lies in the excess electricity consumption generated, this criterion being particularly sensitive in the case of electric vehicles for which the loss of autonomy can be relatively significant.

[0018] Also known from document US 2020 / 0376934 A1 is an HVAC module comprising: - a housing defining an air inlet and an air outlet connected by an air duct, this air inlet being able to be fluidically connected selectively to an exterior air intake duct and to a passenger compartment air recirculation duct; - a first air filter positioned inside the air duct; - a second HEPA-type air filter positioned downstream of the first air filter inside the air duct; and - an airflow control flap positioned in the housing and selectively operable to connect the air passage to a bypass duct further defined by the housing.

[0019] The bypass duct has an inlet located at the flap and opening into the air duct downstream of the first air filter and upstream of the second HEPA air filter. This bypass duct also has a outlet opening into the bypass line downstream of the second HEPA air filter.

[0020] Thus, depending on the position of the control flap, the air flow passes either only through the first air filter, or successively through this first air filter and the second HEPA filter.

[0021] Such an installation of the second HEPA filter downstream of the first air filter in the HVAC module unfortunately requires drastically limiting its dimensions and therefore its efficiency. [Statement of the invention]

[0022] The present invention therefore aims to improve the situation.

[0023] To this end, it proposes an air treatment system for a motor vehicle comprising an outside air intake duct, a passenger compartment air recirculation duct, a diffusion duct opening into the passenger compartment of said vehicle and housing a motor-fan unit and a first air filter; characterized in that it also comprises: - a two-way circulation filtration duct housing a second HEPA-type air filter and extending between the outlet of said intake duct and the outlet of said recirculation duct, - a first bypass duct extending between the outlet of said intake duct and the inlet of the diffusion duct, and - a second bypass duct extending between the outlet of said recirculation duct and the inlet of said diffusion duct, said system further comprising: - a first air flow control flap arranged at the interface between the outlet of said intake duct, a first inlet / outlet of said filtration duct and the inlet of said first bypass duct; and - a second air flow control flap, arranged at the interface between the outlet of said recirculation duct, the second inlet / outlet of said filtration duct and the inlet of said second bypass duct.

[0024] The air treatment system according to the invention thus makes it possible to control the path of the air flow (external or recycled) according to different configurations. such that it can selectively pass through either only the first air filter, bypassing the second HEPA air filter, or successively pass through this second HEPA air filter and this first air filter.

[0025] Furthermore, such an air treatment system according to the invention is perfectly compatible with the installation of the second HEPA air filter in the engine compartment of the vehicle, so that its dimensions and therefore its efficiency are optimal.

[0026] According to a preferred characteristic of said air treatment system according to the invention, said first control flap is movable between: - a first position in which said intake duct, said first bypass duct and said filtration duct are fluidically connected; - a second position in which only said intake and filtration ducts are fluidically connected while the inlet of said first bypass duct is closed; and - a third position in which only said filtration duct and said first bypass duct are fluidically connected while the outlet of said intake duct is closed; said second control flap being movable between: - a first position in which only said filtration duct and said second bypass duct are fluidically connected, while the outlet of said recirculation duct is closed; and - a second position in which only said recirculation and filtration conduits are fluidically connected, while the inlet of said second bypass conduit is closed.

[0027] The air treatment system according to the invention is advantageously capable of operating in a first mode in which: - said first control flap occupies its first position so that the pulsed air, entering the passenger compartment and coming only from outside the vehicle, circulates successively in said intake duct, said first bypass duct and said diffusion duct while passing only through said first air filter, and - said motor-fan unit operates at its maximum electrical power.

[0028] This first operating mode is, for example, configured to activate automatically in the presence of at least one passenger in the vehicle and when the temperature in the passenger compartment is above a predetermined threshold temperature.

[0029] The air treatment system according to the invention is also advantageously capable of operating in a second mode in which: - said first control flap occupies its second position and where said second control flap occupies its first position, so that the pulsed air, entering the passenger compartment and coming only from outside the vehicle, circulates successively in said intake duct, said filtration duct, said second bypass duct and said diffusion duct, passing successively through said second HEPA air filter and said first air filter; and - said motor-fan unit operates at its maximum electrical power.

[0030] This second operating mode is, for example, configured to activate automatically when there are no passengers in the vehicle and when the temperature inside the passenger compartment is above a predetermined threshold temperature.

[0031] According to one feature, the face of this second HEPA air filter crossed first by the air flow in said second operating mode is covered with an antistatic pre-filter.

[0032] The air treatment system according to the invention is further advantageously capable of operating in a third mode in which said first control flap occupies its third position and where said second control flap occupies its second position, so that the pulsed air, entering the passenger compartment and consisting solely of recycled air, circulates successively in said recirculation duct, said filtration duct, said first bypass duct and said diffusion duct, successively passing through said second HEPA air filter and said first air filter.

[0033] This third operating mode is, for example, configured to activate automatically in the presence of at least one passenger in the vehicle and when the temperature in the passenger compartment is less than or equal to a predetermined threshold temperature.

[0034] The invention also relates, in a second aspect, to a motor vehicle comprising such an air treatment system. [Brief description of the drawings]

[0035] The description of the invention will now be continued by the detailed description of several exemplary embodiments, given below for illustrative but non-limiting purposes, with reference to the appended drawings, in which: - [Fig 1] represents a schematic view of an HVAC air treatment system according to the invention for a motor vehicle; - [Fig 2] is a view of the HVAC air treatment system according to the invention in a configuration corresponding to its first mode of operation; ■ [Fig 3] represents a view of the HVAC air treatment system according to the invention in a configuration corresponding to its second mode of operation; and - [Fig 4] is a view of the HVAC air treatment system according to the invention in a configuration corresponding to its third mode of operation. [Detailed description]

[0036] With reference to Figure 1, the HVAC air treatment system 1 according to the invention comprises: - an external air intake duct 2 whose inlet is fluidically connected to the exterior E of the vehicle; - a passenger compartment air recirculation duct 3 whose inlet is fluidically connected to the interior of the passenger compartment H of the vehicle; - a diffusion duct 4 whose outlet is fluidically connected to the interior of the passenger compartment H of the vehicle, this diffusion duct 4 housing a motor-fan unit 5 as well as a first air filter 6; - a two-way circulation filtration duct 7 extending between the outlet of the intake duct 2 and the outlet of the recirculation duct 3, this filtration duct 7 housing a second HEPA type air filter 8; - a first bypass duct 9 extending between the outlet of the intake duct 2 and the inlet of the diffusion duct 4; and - a second bypass duct 10 extending between the outlet of the recirculation duct 3 and the inlet of the diffusion duct 4.

[0037] In the remainder of this description, the terms “upstream” and “downstream” used to characterize the position of certain elements of the air treatment system 1 will be considered in relation to the direction of circulation of the air flow in the ducts 2, 3, 4, 9 and 10.

[0038] The first air filter 6 is advantageously constituted by a high efficiency (HE) filter making it possible to filter gaseous pollutants such as volatile organic compounds (VOCs), dust and fine particles such as those with an average diameter of 2.5 pm (PM 2.5) and those with an average diameter of 9 pm (PM 9).

[0039] This first air filter 6 can also be made up of a simple pollen filter, an activated carbon filter for filtering and neutralizing odors, or a biocidal filter ensuring more effective filtering of allergens. This filter 6 can also be made up of a plurality of layers, each layer performing the function of one of the filters defined previously.

[0040] The second HEPA 8 type air filter is advantageously class H13 so as to ensure the filtering of at least 99.95% of fine particles, invisible to the naked eye, with a diameter greater than or equal to 0.3 micrometers (pm).

[0041] According to alternative embodiments, this second HEPA 8 filter can be of an even more efficient class (for example, class H14 ensuring the filtering of at least 99.995% of fine particles, invisible to the naked eye, with a diameter greater than or equal to 0.3 micrometers).

[0042] This second HEPA filter 8 is also advantageously installed in the engine compartment of the vehicle located under the front hood, so that the passenger compartment air recirculation ducts 3 and the bypass ducts 9, 10 pass through the bulkhead of the vehicle separating the engine compartment and the passenger compartment, this bulkhead being shown schematically in this figure 1 by the broken line T.

[0043] The HVAC air treatment system 1 also comprises a first air flow control flap 11, arranged at the interface between the outlet of the intake duct 2, a first inlet / outlet of the filtration duct 7 and the inlet of the first bypass duct 9.

[0044] This first control flap 11 is movable via a motorized actuator not shown between: - a first position (see figure 2) in which the intake duct 2, the first bypass duct 9 and the filtration duct 7 are fluidically connected; - a second position (see figure 3) in which only the intake ducts 2 and filtration ducts 7 are fluidically connected, while the inlet of the first bypass duct 9 is closed; and - a third position (see figure 4) in which only the filtration duct 7 and the first bypass duct 9 are fluidically connected, while the outlet of the intake duct 2 is closed.

[0045] The HVAC air treatment system 1 further comprises a second air flow control flap 12, arranged at the interface between the outlet of the recirculation duct 3, the second inlet / outlet of the filtration duct 7 and the inlet of the second bypass duct 10.

[0046] This second control flap 12 is movable via a motorized actuator not shown between: - a first position (see figures 2 and 3) in which only the filtration duct 7 and the second bypass duct 10 are fluidically connected, while the outlet of the recirculation duct 3 is closed; and - a second position (see figure 4) in which only the recirculation 3 and filtration 7 conduits are fluidically connected, while the inlet of the second bypass conduit 10 is closed.

[0047] The HVAC air treatment system 1 also comprises a supervision module (not shown) capable of managing, autonomously or according to control orders transmitted by the passengers of the vehicle, the operation of the motor-fan unit 5 in order to adapt the flow of pulsed air leaving the latter as well as the operation of the first and second air flow control flaps 11, 12.

[0048] Preferably made up of the vehicle's BSI (for "Intelligent Servitude Box") also called VSM (for "Vehicle Supervisor Module" in English) in common terminology, this supervision module includes a computer having one or more interconnected microprocessors, as well as a memory module comprising non-volatile and non-volatile memory.

[0049] This supervision module is capable of operating the HVAC 1 air treatment system of the vehicle in a first mode called “rapid cooling” illustrated by Figure 2 and in which: - the first air flow control flap 11 occupies its first position so that the pulsed air, entering the passenger compartment H and coming only from the exterior E of the vehicle, circulates successively in the exterior air intake duct 2, the first bypass duct 9 and the diffusion duct 4, passing only through the first air filter 6, and - the motor-fan unit 5 operates at its maximum electrical power.

[0050] This first operating mode may, for example, be configured to activate automatically in the presence of at least one passenger in the vehicle and when the temperature within the passenger compartment H is higher than a predetermined threshold temperature (for example, between 35 and 40°C). It may also be envisaged that this first operating mode may be activated manually by a passenger in the vehicle.

[0051] The second HEPA filter 8 is therefore bypassed when this first operating mode is activated (the entire air flow passing through the first bypass duct 9 which offers no resistance to the passage of air unlike the filtration duct 7), so that the pressure losses are contained and a sufficient air flow rate at the passenger compartment inlet (approximately 500 kg / h) can be obtained without oversizing the motor-fan unit 5 (and therefore with limited electrical consumption as well as reduced operating cost and noise).

[0052] In this first operating mode, the second air flow control flap 12 advantageously occupies its first position in which the outlet of the recirculation duct 3 is closed, so as to reduce the intensity of the parasitic noise generated in the passenger compartment H.

[0053] The supervision module is also capable of operating the vehicle's air treatment HVAC system 1 in a second mode called “preconditioning” illustrated by Figure 3, in which: - the first air flow control flap 11 occupies its second position and where the second air flow control flap 12 occupies its first position, so that the pulsed air, entering the passenger compartment H and coming only from the exterior E of the vehicle, circulates successively in the exterior air intake duct 2, the filtration duct 7, the second bypass duct 10 and the diffusion duct 4, passing successively through the second HEPA air filter 8 and the first air filter 6; and - the motor-fan unit 5 operates at its maximum electrical power.

[0054] This second operating mode can for example be configured to activate automatically in the absence of a passenger in the vehicle and when the temperature within the passenger compartment H is higher than a predetermined threshold temperature (advantageously the same as that associated with the triggering of the first operating mode called “rapid cooling”, so that the two modes follow one another automatically). It is also possible to envisage that this second operating mode can be activated manually by a passenger in the vehicle.

[0055] This second operating mode thus makes it possible to cool the passenger compartment H before passengers enter the vehicle while maintaining optimal filtration quality.

[0056] The reduction in the air flow rate at the passenger compartment inlet caused by the greater pressure losses generated by the passage of this second HEPA 8 air filter naturally results in cooling occurring more slowly compared to the first operating mode. This is not, however, problematic in this case considering that there is no imperative here to reach a bearable temperature in the passenger compartment as quickly as possible (which is, however, obviously the case in the presence of at least one passenger).

[0057] The supervision module is further capable of operating the HVAC air treatment system 1 of the vehicle in a third mode called “thermal convergence” illustrated by Figure 4, in which the first air flow control flap 11 occupies its third position and where the second air flow control flap 12 occupies its second position, so that the pulsed air, entering the passenger compartment H and consisting solely of recycled air, circulates successively in the recirculation duct 3, the filtration duct 7 (the air flow circulating there in the opposite direction to that in the second operating mode), the first bypass duct 9 and the diffusion duct 4, successively passing through the second HEPA air filter 8 and the first air filter 6.

[0058] This third operating mode, intended to converge the temperature in the passenger compartment H towards a predefined set temperature, can for example be configured to activate automatically in the presence of at least one passenger in the vehicle and when the temperature within the passenger compartment H is less than or equal to a predetermined threshold temperature (advantageously the same as that associated with the triggering of the first operating mode called “rapid cooling”, so that the two modes follow one another automatically). It is also possible to envisage that this third operating mode can be activated manually by a passenger in the vehicle.

[0059] This third operating mode also ensures optimal filtration quality. Since the difference between the interior temperature of the passenger compartment H and the set temperature is less than in the first operating mode, the reduction in air flow at the passenger compartment inlet caused by the greater pressure losses generated by the passage through this second HEPA 8 air filter is no longer a problem.

[0060] Preferably, the face of this second HEPA air filter 8 crossed first by the air flow in the second operating mode called “preconditioning” (illustrated by figure 3) is covered with an antistatic pre-filter 8A intended to retain the largest part of the particles sucked in from the outside air, so as to prevent this HEPA filter 8 from becoming too quickly saturated or obstructed.

[0061] In order to reduce operating noise, the supervision module will be advantageously configured so as to gradually reduce the electrical power of the motor-fan unit 5 as the differential between the temperature within the passenger compartment H and the outside temperature decreases.

[0062] Many variant embodiments are of course conceivable and it is recalled in this respect that the present invention is not limited to the embodiments described and shown, but also encompasses all variant embodiments within the reach of those skilled in the art, i

Claims

Claims

1. Air treatment system (1) for a motor vehicle comprising an outside air intake duct (2), a passenger compartment air recirculation duct (3), a diffusion duct (4) opening into the passenger compartment (H) of said vehicle and housing a motor-fan unit (5) as well as a first air filter (6); characterized in that it also comprises: - a two-way circulation filtration duct (7) housing a second HEPA type air filter (8) and extending between the outlet of said intake duct (2) and the outlet of said recirculation duct (3), - a first bypass duct (9) extending between the outlet of said intake duct (2) and the inlet of the diffusion duct (4), and - a second bypass duct (10) extending between the outlet of said recirculation duct (3) and the inlet of said diffusion duct (4), said system further comprising: - a first air flow control flap (11) arranged at the interface between the outlet of said intake duct (2), a first inlet / outlet of said filtration duct (7) and the inlet of said first bypass duct (9); and - a second air flow control flap (12), arranged at the interface between the outlet of said recirculation duct (3), the second inlet / outlet of said filtration duct (7) and the inlet of said second bypass duct (10).

2. Air treatment system (1) according to claim 1, characterized in that said first control flap (11) is movable between: - a first position in which said intake duct (2), said first bypass duct (9) and said filtration duct (7) are fluidically connected; - a second position in which only said intake (2) and filtration (7) conduits are fluidically connected while the inlet of said first bypass conduit (9) is closed; and - a third position in which only said filtration duct (7) and said first bypass duct (9) are fluidically connected while the outlet of said intake duct (2) is closed; said second control flap (12) being movable between: - a first position in which only said filtration duct (7) and said second bypass duct (10) are fluidically connected, while the outlet of said recirculation duct (3) is closed; and - a second position in which only said recirculation (3) and filtration (7) conduits are fluidically connected, while the inlet of said second bypass conduit (10) is closed.

3. Air treatment system (1) according to claim 2, characterized in that it is capable of operating in a first mode in which: - said first control flap (11) occupies its first position so that the pulsed air, entering the passenger compartment (H) and coming only from the exterior (E) of the vehicle, circulates successively in said intake duct (2), said first bypass duct (9) and said diffusion duct (4) passing only through said first air filter (6), and - said motor-fan unit (5) operates at its maximum electrical power.

4. Air treatment system (1) according to claim 3, characterized in that said first operating mode is configured to activate automatically in the presence of at least one passenger in the vehicle and when the temperature within the passenger compartment (H) is higher than a predetermined threshold temperature.

5. Air treatment system (1) according to one of claims 2 to 4, characterized in that it is capable of operating in a second mode in which: - said first control flap (11) occupies its second position and where said second control flap (12) occupies its first position, so that the pulsed air, entering the passenger compartment (H) and coming only from the exterior (E) of the vehicle, circulates successively in said intake duct (2), said filtration duct (7), said second bypass duct (10) and said diffusion duct (4) by successively passing through said second HEPA air filter (8) and said first air filter (6); and - said motor-fan unit (5) operates at its maximum electrical power.

6. Air treatment system (1) according to claim 5, characterized in that said second mode is configured to activate automatically in the absence of a passenger in the vehicle and when the temperature within the passenger compartment (H) is higher than a predetermined threshold temperature.

7. Air treatment system (1) according to one of claims 5 or 6, characterized in that the face of said second HEPA air filter (8) crossed first by the air flow in said second operating mode is covered with an antistatic pre-filter (8A).

8. Air treatment system (1) according to one of claims 2 to 7, characterized in that it is capable of operating in a third mode in which said first control flap (11) occupies its third position and where said second control flap (12) occupies its second position, so that the pulsed air, entering the passenger compartment (H) and consisting solely of recycled air, circulates successively in said recirculation duct (3), said filtration duct (7), said first bypass duct (9) and said diffusion duct (4) by successively passing through said second HEPA air filter (8) and said first air filter (6).

9. Air treatment system (1) according to claim 8, characterized in that said third operating mode is configured to activate automatically in the presence of at least one passenger in the vehicle and when the temperature within the passenger compartment (H) is less than or equal to a predetermined threshold temperature.

10. Motor vehicle comprising an air treatment system (1) according to one of claims 1 to 9.

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