FR3046845A1 - SYSTEM AND METHOD FOR MEASURING AIR QUALITY IN THE CABIN OF A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a system (1) for measuring the quality of the air (2A) within the passenger compartment of a motor vehicle by absorption of a light (L1) passing through the air (2A) said system (1) comprising: - at least one light source (11) adapted to emit light, of which at least a first portion (L1) passes through air (2A) whose quality is to be measured, at least a first receiving module (12 ') adapted to receive said first portion of light (L1) not passing through the air (2, 2A, 2B) whose quality is to be measured and for measuring the luminous intensity of the light received, - a second receiving module (12) adapted to receive a second portion (L2) of the light emitted by the light source (11) and to measure its light intensity, and - a light guide ( 13) adapted to guide the second light portion (L2) of the light source (11) to the second receiving module (12).

Description

SYSTEM AND METHOD FOR MEASURING AIR QUALITY IN THE CABIN OF A MOTOR VEHICLE

[001] The invention relates to the field of motor vehicles, and aims in particular a system for measuring the quality of the air within a vehicle interior.

[002] A motor vehicle includes an air management system within the passenger compartment of the vehicle to ensure the comfort of passengers of the motor vehicle during a journey. Such a HVAC system for Heating Ventillation and Air Conditioning in English, meaning Heating, Ventilation and Air Conditioning, now takes into account a new element: air pollution. In fact, the level of air pollution reaches a level such that it is unpleasant or dangerous for a passenger of the vehicle to breathe such air.

[003] Also, HVAC systems allow the depollution of air within the cabin of the vehicle. Such systems are, for example, activated when a predetermined level of air pollution is reached.

[004] In order to determine the level of air pollution, it is known to make measurements of the air quality inside and / or outside the passenger compartment of the vehicle, particularly in measuring the concentration of certain polluting gases, such as ozone and nitrogen dioxide, in the air. A known method consists in measuring the absorbance of a light passing through an air thickness, the level of pollution of which it is desired to measure. For this purpose, a light source emits light through the air and a measurement sensor is placed at a distance from the light source to receive the light emitted by the source and having passed through a thickness of air at measure. By comparing the light emitted and the light received, it is possible to determine the presence of polluting gases and their concentration in the air in order to determine the level of pollution.

[005] It is known to use a theoretical value, generally provided by the manufacturer, of the light emitted by the source. However, such a theoretical value may differ from the light actually emitted which can distort the measurements. In addition, the light emitted by the source may vary during its lifetime and differ from the theoretical value used and cause the disadvantages described above.

[006] It is also known, from document US2006255278A1, to use two light sources: one serves as a reference value while the second, whose light passes through an air thickness, can measure the level of pollution air compared to the reference value. However, the two light sources can deviate from each other during use, which can cause errors in measurements and is therefore a disadvantage.

[007] The invention therefore aims to solve these disadvantages by proposing a system for measuring the quality of air within a vehicle interior allowing a reliable and effective measurement of air quality within the vehicle. cabin.

[008] To achieve this result, the present invention relates to a system for measuring the quality of the air within the passenger compartment of a motor vehicle by absorption of a light passing through the air, said system comprising at least one light source adapted to emit light, at least a first portion of said light passing through the air whose quality is to be measured, at least a first reception module adapted to receive said first portion of light; the light and to measure the luminous intensity of the light received, - a second reception module adapted to receive a second part of the light emitted by the light source not passing through the air whose quality is to be measured and measuring the light intensity, and - a light guide adapted to guide the second light portion of the light source to the second receiving module.

With the device according to the invention, it is possible to determine the concentration of a polluting gas in the air of the passenger compartment of the vehicle by comparing the intensity of the light absorbed by said pollutant gas to the reference intensity of the light emitted. The reference intensity of the emitted light is determined by guiding a portion of the emitted light. Thus, the reference intensity of the emitted light can be determined during the measurement of the air quality which increases the reliability of such a measurement. In addition, the same light source emits two parts of light: a part that passes through the air whose quality is to be measured and a part that is guided to determine the reference intensity, which allows to increase the reliability of the measurement of the quality of the air.

Advantageously, the light guide is adapted to directly guide the second light portion of the light source to the second receiving module.

Advantageously, the first part and the second part of the light are emitted simultaneously by the light source.

[0012] Advantageously, the light guide comprises polycarbonate.

Advantageously, the system comprises at least a second light source adapted to emit light, at least a first portion of said light passing through the air whose quality is to be measured, the second receiving module being adapted to receiving said first portion of the light emitted by the second light source and measuring the light intensity of the light received, the first receiving module being adapted to receive a second portion of the light emitted by the second light source and measuring the light intensity, the system comprising a second light guide adapted to guide the second portion of the light of the second light source to the first receiving module.

Advantageously, the system comprises a first plurality of light sources, each light source being adapted to emit a first portion of light passing through the air whose quality is to be measured and received by the first reception module and a second light portion guided by the light guide of said light source to the second receiving module.

The invention also relates to a motor vehicle comprising a system, as described above, for measuring the quality of the air within the passenger compartment of said vehicle.

The invention also provides a method for measuring the quality of air within the passenger compartment of a motor vehicle, said vehicle comprising a measuring system comprising at least one light source, a first module receiver and a second receiver module adapted to receive and determine the intensity of at least a portion of the light emitted by the light source and a light guide connecting the light source to the second receiver module, the method comprising a step of simultaneous emission by the light source of a first portion and a second portion of light, a step of reception by the first receiving module of the first portion of light having passed through a layer of light; air whose quality is to be measured, - a step of reception by the second receiving module of the second part of light that has not passed through the air whose quality is suitable r and guided by the light guide, and - a step of determining the quality of the air layer by comparing the light intensity of the light received by each of the receiving modules.

Advantageously, the measurement system comprising at least a second light source and a second light guide connecting the second light source to the first receiving module, the method comprises an alternative control step of the first light source and of the second light source.

Other features and advantages of the invention will appear on reading the detailed description of the embodiments of the invention, given by way of example only, and with reference to the drawings which show: FIG. 1 a diagram of a vehicle passenger compartment in which a measuring system according to the invention is installed; • FIGS. 2 and 3, operating diagrams of the measuring system of FIG. 1, and • FIGS. 4 and 5, control signals of the measuring system of Figure 1.

In what follows, the described embodiments focus more particularly on an implementation of the system according to the invention within a motor vehicle. However, any implementation in a different context, in particular in any type of vehicle, is also covered by the present invention.

Figure 1 shows a system 1 according to the present invention for measuring the quality of air 2 within the passenger compartment 3 of a motor vehicle 4.

The motor vehicle 4 further comprises means 5 for ventilating the air 2 in the passenger compartment 3.

The ventilation means 5 are adapted to be supplied with outside air 2A or air 2 of the passenger compartment 3 in order to supply the passenger compartment 3 with air 2B. To do this, the ventilation means 5 comprise an aerator 51 through which air 2B enters the passenger compartment 3. Such an aerator 51 is in the form of nozzles installed in the passenger compartment 3 and may include a fan ( not shown) to facilitate the flow of air. An air filter 52 placed upstream of the aerator 51 makes it possible to filter certain polluting particles present in the air 2A, 2 supplying the ventilation means 5 so that the air 2B entering the passenger compartment 3 is healthy for vehicle passengers 4. Such an air filter 52 may, for example, be an activated carbon filter.

It has been presented an air filter 52 for cleaning the air 2A, 2 flowing through the ventilation means 5, but it goes without saying that any other air pollution control system could be suitable, for example ionizing, catalytic, absorbent systems, etc.

The measuring system 1 is located downstream of the ventilation means 5 as shown in Figure 1 to measure the quality of the air entering the passenger compartment 2B 3. However, the measurement system 1 could be mounted at another place, in particular upstream of the ventilation means 5 in order to measure the quality of the outside air 2A, in other words, before their depollution by the ventilation means 5.

Referring to Figures 2 and 3 and according to one embodiment of the system according to the invention, the measuring system 1 is adapted to measure the quality of the air 2A upstream of the ventilation means 5 and to measure the quality of the air 2B downstream of the ventilation means 5. Thus, the measurement system 1 makes it possible to compare the quality of the air 2 before and after depollution and thus determine the effectiveness of such a depollution of the air air 2.

The measuring system 1 can determine the level of pollution of the air 2 by measuring the absorption of a light passing through the air 2. The intensity of the light after absorption is compared with the intensity light emitted by its source to deduce the presence and concentration of gaseous pollutants as will be described later.

To do this, again with reference to Figures 2 and 3, the measuring system 1 comprises a first measuring device 10 and a second measuring device 10 '. Each measuring device 10, 10 'comprises a light source 11, 11', a receiving module 12, 12 'adapted to receive light and a guide 13, 13' adapted to guide a part of the light emitted by the light. light source 11, 11 'directly to the receiving module 12, 12'. The light source 11, 11 'and the receiving module 12, 12' are mounted on a support structure 14, 14 'of the measuring device 10, 10'.

The light source 11, 11 'is adapted to emit light. At least a portion of the light emitted by the light source 11, 11 'passes through a predetermined thickness of air 2A, 2B in order to deduce the level of pollution as will be described later. At least a portion of the light emitted by the light source 11, 11 'is guided to the receiving module 12, 12' via the guide 13, 13 'in order to determine the intensity of the light emitted by the light source 11, 11 'as will be described later. The light source 11, 11 'emits light whose light intensity is referred to as the reference intensity 10 in order to be compared with the intensity I of the light received by a reception module 12, 12' of which a part has absorbed by the pollutant gas to be measured.

The light source 11, 11 'is adapted to emit light whose wavelength is predetermined. The wavelength is determined according to the pollutant gas whose concentration is to be determined in the air 2 whose quality is to be measured.

Such a light source 11, 11 'may, for example, be in the form of a laser, a light-emitting diode, also designated LED, or a xenon lamp, deuterium or tungsten, etc. .

The receiving module 12, 12 'is adapted to receive at least a portion of the light emitted by the light source 11, 11' in order to measure the light intensity. Advantageously, the receiving module 12, 12 'can be configured to measure the light intensity of the light only at a predetermined wavelength.

The receiving module 12, 12 'can receive light emitted by the light source 11, 11' via the guide 13, 13 'in order to determine the reference light intensity 10 of the light emitted by said source. of light 11, 11 '. The receiving module 12, 12 'can also receive light emitted by a light source 11, 11' and having passed through an air thickness 2 in order to measure the luminous intensity I after absorption in said air 2.

Such a receiving module 12, 12 'may, for example, be in the form of a photodiode, a photographic sensor, also called CCD sensor, a camera, a thermopile or a photo-multiplier, etc.

The guide 13, 13 'is adapted to guide at least a portion L2, L2' of the light emitted by the light source 11, 11 'directly to the receiving module 12, 12'. Thus, said light portion L2, L2 'does not pass through the air 2 whose level of pollution it is desired to measure in order to determine the reference light intensity 10 of the light source 11, 11 Such a guide 13, 13' can for example, be made of polycarbonate.

As illustrated in Figures 2 and 3, the measuring system 1 comprises two measuring modules 10, 10 'mounted face to face and separated by a predetermined distance D to form an air passage 2 which is desired measure the level of pollution.

The light sources 11, 11 'of the measuring modules 10, 10' are controlled so that a single light source 11, 11 'at a time does not emit light.

When light is emitted by the light source 11 of the first measurement module 10 and with reference to FIG. 2, a first portion L1 of the light emitted by the light source 11 of the first measurement module 10 crosses a thickness D of air 2A to the measuring module 10 'of the second measurement module 10' so that the latter measures the intensity I of the light after absorption by the air 2A crossed. A second portion L2 of the light emitted by the light source 11 of the first module 10 is guided by the guide 13 to the receiving module 12 of the first module 10 in order to determine the reference intensity 10 of the first light source. 11.

According to an advantageous aspect of the invention, the first light portion L1 and the second light portion L2 are simultaneously emitted by the light source 10. Thus, the measured reference intensity 10 corresponds to the light emitted by the light source 10 and then received by the measuring module 10 'after passing through the air 2 A which is to measure the level of pollution.

By comparing the intensity I after absorption by the outside air 2A at the reference intensity 10, it is possible to determine the concentration of a polluting gas in said outside air 2A.

To do this, we apply the law of Lambert Beer such as: [0041] (1)

Where A is the absorbance of air 2A, ε is the molar absorption coefficient of the polluting gas, D is the thickness of air 2A crossed by the light and C is the molar concentration of the polluting gas.

Thus, to find the concentration C in the outside air 2A of a desired polluting gas, such as ozone or nitrogen dioxide, the equation (1) is applied to said pollutant gas using its coefficient molar absorption ε. In addition, in order to ensure that only the desired polluting gas absorbs the light emitted by the light source 11 and that it is its concentration that is measured, said light source 11 emits light whose wavelength is characteristic of the polluting gas. Such a characteristic wavelength corresponds to a wavelength absorbed by said polluting gas and not by other gases present in the air 2A.

The determination of the concentration of a gas in air by the law of Beer Lambert is known and will not be described in more detail.

When light is emitted by the light source 11 'of the second measurement module 10' and with reference to FIG. 3, a first portion L1 'of the light emitted by the light source 11' of the second measuring module 10 'passes through a thickness D of air 2B to the measurement module 10 of the first measurement module 10 in order to measure the intensity I of the light after absorption by the crossed air 2B. A second portion L2 'of the light emitted by the light source 11' of the second module 10 'is guided by the guide 13' to the receiving module 12 'of the second module 10' in order to determine the reference intensity 10. of the second light source 11 '.

As described above, it is then possible to determine the concentration of a polluting gas in the air 2B entering the passenger compartment 3 of the vehicle 4. Thus, thanks to the system 1 measuring the concentration of a polluting gas in upstream and downstream of the air filter 52, it is possible to determine the efficiency of said air filter 52.

It has been presented a measuring system 1 comprising two measurement modules 10, 10 'in order to measure the concentration of a pollutant gas upstream and downstream of an air filter 52, however, it goes without saying that such a measuring system 1 could be used without an air filter 52, in particular for measuring the concentration of two pollutant gases, each light source 11, 11 'of the measuring system 1 then emitting light at a length of different wave, each wavelength being characteristic of one of the polluting gases.

As illustrated in Figures 4 and 5, the light sources 11, 11 'and the receiving modules 12, 12' are controlled alternately. In other words, the light source 11 of the first measurement module 10 emits light (at a high level of the control signal P1 of the light source 11) and then the light source 11 'of the second measurement module 10 emits light (at a high level of the light source control signal P1 ') and so on so that at each instant only one of the light sources 11, 11' emit light. In other words, the light sources 11, 11 'are controlled in phase opposition. In the case of a measuring system 1 comprising more than two light sources 11, 11 ', their phase shift would also be opposite to the number of light sources 11, 11' of the measuring system 1.

Each receiving module 12, 12 'is also controlled so as to alternately determine the reference intensity 10 of the light source 11, 11' of the measurement module 10, 10 'of said receiving module 12, 12' (at a low level of the P2 signal, P2 'control of the receiving module 12, 12') and the intensity of the light received from the light source 11, 11 'of the other measurement module 10, 10 '(at a high level of signal P2, P2' control of the receiving module 12, 12 '). Thus, only two receiving modules 12, 12 'are required to measure the absorption of the light emitted by a plurality of alternately controlled light sources 11, 11'.

The measurement system 1 could also include more than two light sources 11, 11 '. To this end, each measuring device 10, 10 'could comprise a plurality of light sources 11, 11' emitting light of different wavelengths, said light sources 11, 11 'being connected to the reception module 12 , 12 'of the measuring device 10, 10' by a light guide 13, 13 'to determine the reference intensity 10 of each light source 11, 11'. Advantageously, the light guide 13, 13 'of a measurement module 10, 10' can be in the form of a single polycarbonate plate making it possible to connect all the light sources 11, 11 'of the light module. measuring 10, 10 'to the receiving module 12, 12'.

It is specified, moreover, that the present invention is not limited to the examples described above and is capable of variants accessible to those skilled in the art.

Claims (9)

Claims: 1. System (1) for measuring the quality of the air (2, 2A, 2B) within the passenger compartment (3) of a motor vehicle (4) by absorption of a light (L1, L1 ' ) passing through air (2, 2A, 2B), said system (1) comprising: - at least one light source (11, 11 ') adapted to emit light, at least a first portion (L1, L1 ') of said light passing through the air (2, 2A, 2B) whose quality is to be measured, - at least a first receiving module (12, 12') adapted to receive said first light portion (L1, L1 ') and for measuring the luminous intensity (I) of the light received, - a second reception module (12, 12') adapted to receive a second portion (L2, L2 ') of the light emitted by the light source (11, 11 ') not passing through the air (2, 2A, 2B) whose quality is to be measured and to measure its luminous intensity (l0), and - a light guide (13, 13') adapted to guide the second by light section (L2, 12 ') of the light source (11, 1Γ) to the second receiving module (12, 12'). 2. System (1) according to claim 1, wherein the light guide (13, 13 ') is adapted to directly guide the second portion (L2, L2') of light of the light source (11, 11 '). ) to the second receiving module (12, 12 '). 3. System (1) according to one of the preceding claims, wherein the first portion (L1, L1 ') and the second portion (L2, L2') of the light are emitted simultaneously by the light source (11, 11 '). 4. System (1) according to one of the preceding claims, wherein the light guide (13, 13 ') comprises polycarbonate. 5. System (1) according to one of the preceding claims, comprising at least a second light source (11, 11 ') adapted to emit light, at least a first portion (L1, Ι_Γ) of said through light of the air (2, 2A, 2B) whose quality is to be measured, the second receiving module (12, 12 ') being adapted to receive said first part (L1, U') of the light emitted by the second source of light (12, 12 ') and for measuring the light intensity (I) of the light received, the first receiving module (12, 12') being adapted to receive a second portion (L2, 12 ') of the light emitted by the second light source (11, 11 ') and measuring its light intensity (10), the system (1) comprising a second light guide (13, 13') adapted to guide the second part (L2 , L2 ') of the light of the second light source (L1, L1') to the first receiving module (12, 12 '). 6. System (1) according to one of the preceding claims comprising a first plurality of light sources (11, 11 '), each light source (11, 11') being adapted to emit a first light portion (L1, L1 ') passing through air (2, 2A, 2B) whose quality is to be measured and received by the first receiving module (11, 11') and a second light portion (L2, L2 ') guided by the light guide (13, 13 ') of said light source (11, 11') to the second receiving module (12, 12 '). 7. Motor vehicle (4) comprising a system (1) according to one of the preceding claims, for measuring the quality of the air (2, 2A, 2B) within the passenger compartment (3) of said vehicle (4). ). 8. A method for measuring the quality of the air (2, 2A, 2B) within the passenger compartment (3) of a motor vehicle (4), said vehicle (4) comprising a measuring system (1) according to one of claims 1 to 6, said system (1) comprising at least one light source (11, 11 '), a first reception module (12, 12') and a second reception module (12, 12 ') adapted to receive and determine the intensity (I, 10) of at least a portion (L1, L1', L2, L2 ') of the light emitted by the light source (11, 11') and a guide of light (13, 13 ') connecting the light source (11, 11') to the second receiving module (12, 12 '), the method comprising: - a step of simultaneous emission by the light source (11, 11 ') of a first part (L1, L1') and a second part (L2, L2 ') of light, - a step of reception by the first receiving module (12, 12') of the first part of light (L1, L1 ') having passed through a layer of air (2, 2A, 2B) whose quality is to be measured, - a step of reception by the second receiving module (12, 12 ') of the second light part (L2, L2') not having passed through the air whose quality is to be measured and guided by the light guide (13, 13 '), and - a step of determining the quality of the air layer (2, 2A, 2B) by comparing the light intensity (I, l0) of the light received by each of the receiving modules (12, 12 '). Method according to the preceding claim, the measuring system (1) comprising at least a second light source (11, 11 ') and a second light guide (13, 13') connecting the second light source (11, 11 ') to the first receiving module (12, 12'), the method comprising an alternating control step of the first light source (11, 11 ') and the second light source (11, 11').