FR2802620A1 - HEATING AND / OR AIR CONDITIONING SYSTEM WITH DETECTION OF FILTER CLOGGING - Google Patents

Abstract

The invention relates to a heating and / or air conditioning installation having an air circuit equipped with an adsorbent filter (5) and comprising a device for detecting at least one parameter characteristic of the state of the filter (5). According to the invention, the detection device has a pollution sensor (4) capable of measuring at least one significant component of clogging and / or saturation of the filter (5) to generate at least one signal representative of said component as well as a module (M) able to combine the values of at least said signal representative of said component to produce an indication representative of the clogging and / or the saturation of the filter (5).

Description

HEATING AND / OR AIR CONDITIONING INSTALLATION

  HAVING A FILTER CLOGGING DETECTION

  The present invention relates to a heating and / or air conditioning installation which is equipped with an air filter for which a clogging detection device is provided. Already known, for example from Japanese Patent Application JP 10151942 (CALSONIC) published on June 9, 1998, a filter clogging detection device, intended for an installation of this type. The device implements a pressure difference sensor which evaluates the 0o pressure difference between the upstream and downstream of the filter. This difference increases as the filter becomes clogged and a clogging is

  detected when this pressure difference reaches a predetermined value.

  This technique requires the use of a differential sensor (or two sensors), that is to say means which on the one hand are

  expensive and which on the other hand are only used for detecting clogging.

  Another known technique presents similar problems. This is the technique proposed by Japanese Patent Application JP 11034653 (NIPPONDENSO) published on February 9, 1999, which implements an ultrasonic sensor which measures the variation of the resonance frequency of the filter during clogging with respect to at the frequency of

  clean resonance of the filter in new condition.

  There are actually two significant parameters of the efficiency of a filter, namely clogging but also the saturation of the activated carbon contained in the filter. If in general the clogging of the filter occurs before the saturation of the carbon, there are on the other hand a significant number of situations

  in which carbon saturation occurs before clogging.

  A problem with known devices is that they are only capable of detecting clogging. There is indeed no

  known operational technique capable of performing saturation detection.

  The present invention provides a technique which presents

  more flexibility than known techniques.

  The air filter is crossed by air coming from outside the passenger compartment and which is loaded with various pollutants, in particular coming from

other vehicle exhaust.

  The basic idea of the invention is to use a

  pollution to detect clogging and / or saturation of the filter.

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  Such a sensor can be dedicated to this application, but it can also be used for another function, namely, a pollution detection which controls, in a manner known per se, the automatic closing of an air recirculation flap, in the event of excessive outdoor air pollution. The invention thus relates to a heating and / or air conditioning installation having an air circuit equipped with an adsorbent filter and comprising a device for detecting at least one parameter characteristic of the state of the filter characterized in that the device detection presents a 0o pollution sensor able to measure at least one significant component of clogging and / or saturation of the filter to generate at least one signal representative of said measured component as well as a module capable of accumulating the values of at least said signal representative of said component to produce a

  representative indication of clogging and / or saturation of the filter.

  1 5 The installation can be characterized in that the module has a memory memorizing a relationship between the contents of at least one said measured component and of at least one element representative of the clogging and / or of the saturation of the filter, and in that said accumulation is carried out so as to determine a cumulative quantity of at least one said element, said cumulative quantity constituting a said value representative of the clogging and / or of the saturation of the filter. The module can be arranged to receive and take into account at least one additional parameter such as

  the air flow through the filter.

  At least one component measured can be NOx and

especially the NO.

  The element representative of clogging and / or saturation of the filter can be at least one gaseous contaminant of the hydrocarbon type.

monocyclic aromatic.

  At least one component measured can be COx and

especially CO.

  The element representative of clogging and / or saturation of the filter may be at least one particulate contaminant and / or at least one

  gaseous contaminant of the type different from the previous one, such as NO2 or SO2.

  The pollution sensor can be intended for an air inlet of

Installation.

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  It can be placed upstream of the filter, or downstream of it. The installation advantageously includes at least one clogging and / or saturation indication element (sound, visual, intermittent or not, or accessible in the event of maintenance). Other characteristics and advantages of the invention

  will appear better on reading the description which follows, given as

  non-limiting example, in conjunction with the drawings in which: - Figure 1 illustrates a preferred embodiment of an installation according to the invention; - Figure 2 represents a curve illustrating the evolution of the

  CO content detected as a function of the toluene content.

  The Applicant company has identified that there is a correlation between the contents of carbon oxides (COx), of sulfur oxides (SOx,) or of nitrogen oxides (NO,) measured by a

  pollution, and the contents of the elements clogging the filter.

  According to the invention, the values representative of the content of at least one of these components are accumulated over time and clogging (and / or saturation) is detected when the accumulation reaches a limit value.

  determined in advance, which indicates that the filter should be changed.

  Vehicles with an internal combustion engine discharge gaseous contaminants, namely HAM monocyclic aromatic hydrocarbons such as toluene, benzene, etc., into the atmosphere, solid contaminants, namely PAH polycyclic aromatic hydrocarbons, such as indenopyrene, benzopyrene etc ..., and aldehydes, such as

  formaldehyde, acetaldehyde, benzaldehyde.

  Particulate contaminants are trapped by the filter, including activated carbon, and tend to clog it. The clogged filter is no longer effective and lets these particles pass, possibly dangerous for the health of users, and presenting unpleasant odors. Carbon saturation is caused

  mainly by gaseous contaminants such as HAM.

  A pollution sensor, located in the treated air flow ventilating the passenger compartment of the vehicle, is capable of detecting at least one first parameter chosen from the following parameters: the content of carbon oxides (COx), the content of sulfur oxides (SOx) and the oxide content

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  nitrogen (NOx). An electronic module correlates at least one of these first parameters to at least one second parameter chosen from the following parameters: the content of a monocyclic aromatic hydrocarbon (toluene, benzene ...) a polycyclic aromatic hydrocarbon (indenopyrene, benzopyrene, etc.) .) and an aldehyde (formaldehyde, acetaldehyde, benzaldehyde, tolualdehyde ...). The module integrates this second parameter over time. When integration reaches a predetermined threshold value

  corresponding to the clogging of the filter, a signal informs of the clogging of the filter.

  Said correlation is carried out using at least one curve or a formula

o0 pre-saved calibration.

  Since the clogging of the filter is caused by particulate contaminants and the saturation of the carbon is mainly caused by the gaseous contaminants, the correlation or correlations of interest are chosen to detect the clogging and / or saturation of the charcoal and

  warn of the need to change the filter.

  The pollution sensor can be located in the air flow at the inlet of the treatment installation, upstream of the filter or even downstream of it. This positioning does not influence the detection of CO and NO,

  because the air filter does not filter these two components.

  The module can optionally take into account the estimated air flow rate from the current in the blower which circulates the air, the speed of the blower, the control position of the air flow on the dashboard

and / or vehicle speed.

  In a simplified mode, integration is carried out without

  compensation taking into account average operating conditions.

  The filter is sometimes located in a derivative circuit called "bypass", controlled by a shutter and it is then necessary to take into account

the position of this flap.

  If the filter is likely to be crossed by recirculated air, it is recommended to interrupt or weight the detection (or the

  cumulative) when this mode is used.

  The module M can present a means for interrupting or weighting the measurement and / or the accumulation as a function of the position of the shutter of

  bypass 7 and / or the recirculation flap 3.

  The clogging information signal can be in particular visual (indicator light) or audible. It can be persistent, activate by

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  intermittent, for example when starting the vehicle, or be obtained at the

  request during diagnostic / maintenance operations.

  Advantageously, the gaseous contaminants HAM are correlated on CO and the particulate contaminants (particles less than 10 p, s PAH) and the other gaseous contaminants (NO2, SO2) are correlated at the level

from NO.

  It is also possible to directly detect SO2 using the pollution sensor. In this case there is no longer any need to perform correlation. Just integrate the values over time

  I0 obtained by taking into account any parameters (air flow etc ...).

  FIG. 1 illustrates an installation according to the invention, in which a pollution detector 4 is arranged in the channel 1 for the arrival of outside air, a shutter 3 organizing the switching between operating modes from outside air coming from from channel 1 or from recirculated air from channel 2 (or a mixture of the two). The installation further comprises a filter 5 disposed in a bypass channel 6 controlled by a flap 7 (position 5a in FIG. 1), a blower 8, and downstream of this and in a conventional manner, an evaporator 9, a heating element 10, a flap 11 allowing or not an air passage through the

  radiator 10 and air outlets 12 towards the passenger compartment of the vehicle.

  A module M receives the signals from the sensor 4 and performs the calculations making it possible to detect clogging and / or saturation of the filter 5, the result of which may be, for example, a visual or audible alarm on an indicator A. The module M may be part the vehicle computer, which, in this case, performs the calculation and storage functions. It can take the signals it needs, for example air speed, from the signal base of the central computer. The specifics of the M module are then reduced to the input (sensor 4) and output (indicator A) interfaces and

  specific data stored.

  FIG. 1 also represents two possible alternative positions of the filter 5, namely a position 5b arranged in the channel 1 in

  upstream of the shutter 3, or else a position 5c between the blower 8 and the evaporator 9.

  Figure 2 is an example of a correlation curve between the CO content (expressed in pg / m3 of air) and the toluene content (expressed in pg / m3 of air). A pollution sensor gives a signal representing the instantaneous CO content. By integrating this signal and taking into account

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  this diagram as well as any parameters indicated above

  in the description, a cumulative mass of toluene is deduced therefrom. When

  this mass reaches a value corresponding to a given threshold, we consider

that the filter is clogged.

  Similar reasoning applies to the other components

  significant of clogging and / or saturation of the filter.

  It is possible to detect several components and for example to trigger an alarm as soon as a clogging or

saturation is reached.

  The accumulation is subject to a reset each time the filter is changed. To this end, the module can present a means of

reinitialization of said accumulation.

  The pollution sensor can advantageously be a sensor already present to induce an automatic shutdown of the outside air supply (and start of the "recirculated air" mode) in the event that the level of

  incoming air pollution is too high.

  When the vehicle is provided with a positioning system, in particular GPS, it is advantageous to carry out a correction of the cumulation, for example of the correlation, or of the measurement as a function of the geographical position of the vehicle. Indeed, the natural concentration of COx and / or NOx in the air in different regions can be naturally high, this natural content not being related to an element representative of clogging and / or saturation of the filter. The module M can present a means of correcting the measurement or the accumulation as a function of the content

  natural in at least one measured component.

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Claims (14)

  1. Heating and / or air conditioning installation having an air circuit equipped with an adsorbent filter and comprising a device for detecting at least one parameter characteristic of the state of the filter characterized in that the detection device has a pollution sensor (4) capable of measuring at least one significant component of clogging and / or saturation of the filter (5) to generate at least one signal representative of said measured component as well as a module (M) capable of accumulating values at least io of said signal representative of said component to produce a value   representative of clogging and / or saturation of the filter (5).   2. Installation according to claim 1, characterized in that the module (M) has a memory memorizing a relationship between the contents of at least one said measured component and of at least one element i5 representative of clogging and / or of the saturation of the filter (5), and in that said accumulation is carried out to determine a cumulative quantity of at least one said   element, a so-called cumulative quantity constituting a so-called representative value.   3. Installation according to claim 2, characterized in that the module (M) is arranged to receive and take into account at least one   additional parameter such as the air flow rate passing through the filter.   4. Installation according to one of claims 1 to 3   characterized in that at least one component measured is NOx and in especially the NO.   5. Installation according to claim 4, characterized in that the element representative of clogging and / or saturation of the filter (5) is at least one gaseous contaminant of the monocyclic aromatic hydrocarbon type.   6. Installation according to one of the preceding claims,   characterized in that at least one component is COx, and in particular CO. 7. Installation according to claim 6, characterized in that the element representative of clogging and / or saturation of the filter (5) is at least one particulate contaminant and / or at least one gaseous contaminant such as NO2 or NO. 8 2802620   8. Installation according to one of the preceding claims,   characterized in that the pollution sensor (4) is arranged at an inlet air (1) from the installation.   9. Installation according to one of the preceding claims,   characterized in that the pollution sensor (4) is arranged upstream of the filter (5).   10. Installation according to one of the preceding claims,   characterized in that the pollution sensor (4) is arranged downstream of the filter (5).   11. Installation according to one of the preceding claims,   characterized in that it comprises at least one element (A) for indicating the   clogging and / or saturation of the filter (5).   12. Installation according to one of the preceding claims,   characterized in that the module has a means for resetting the is cumulative.   13. Installation according to one of the preceding claims,   characterized in that the module (M) has a means for correcting the measurement or the accumulation as a function of the natural content of at least one component measured.   14. Installation according to one of the preceding claims,   characterized in that the module (M) has a means for interrupting or weighting the measurement and / or the accumulation as a function of the position of a flap (7) of   bypass of the air flow through the filter (5) and / or a recirculation flap (3).