METHOD FOR CONTROLLING THE OPERATION OF A CATALYTIC CONVERTER FOR EXHAUST FUMES FROM A MOTOR VEHICLE INTERNAL COMBUSTION ENGINE

Description

Technical field of the invention

[0001] The invention relates to the field of devices for treating exhaust gases produced by a heat engine fitted to a motor vehicle. The invention relates more specifically to methods for regulating the real-time operation of a catalyst placed on an exhaust line for the gases to be treated, making it possible to improve the performance of the catalyst in treating the exhaust gases prior to their release into the atmosphere. Prior art

[0002] Motor vehicles are commonly equipped with a powertrain comprising at least one internal combustion engine - also known as a heat engine - or even an electric motor in the case of a vehicle with a hybrid propulsion system. Such heat engines are supplied with fuel and oxidizer, the respective quantities of which are regulated. Commonly, the fuel is hydrocarbon-based and the oxidizer is air. As a result of the combustion of the hydrocarbons, the heat engine produces exhaust gases which are conveyed from the heat engine outlet to the outside of the vehicle, via an exhaust line.

[0003] However, complete combustion of fuel is difficult to achieve. As a result, the exhaust gases emitted by the internal combustion engine are often laden with various chemical compounds. For example, such chemical compounds include carbon monoxide (CO), nitrogen oxide (NOx), and unburned hydrocarbons (HC). Such chemical compounds are toxic and, as a result, must be reduced by regulation before exhaust gases are released into the atmosphere.

[0004] For this purpose, the exhaust line incorporates at least one catalyst for treating the exhaust gases by oxidation, exploiting the oxygen present in the exhaust gases. However, the effectiveness of the catalyst in treating the exhaust gases depends on several factors during its operation, such as in particular its temperature which must be sufficiently high at a predefined temperature threshold, the content in the exhaust gases of the chemical agents to be treated, and / or the oxygen storage capacity of the catalyst.

[0005] This is why it is appropriate to monitor in real time the ability of the catalyst to effectively treat the exhaust gases and - in the event of a failure - to intervene to optimize its performance. For this purpose, it is known to install on board the vehicle a control-command device comprising a system for real-time analysis of the operation of the catalyst and a regulator of its operation. In the event that the analysis system identifies a failure of the catalyst to effectively treat the exhaust gases, the regulator is activated to improve its performance.

[0006] To do this, it is common to use oxygen sensors placed on the exhaust line upstream and downstream of the catalyst. Such oxygen sensors are notably voltaic sensors, i.e. measuring an electrical potential. It is notably known to use an upstream sensor providing proportional measurements, and a downstream sensor providing binary measurements. For precision, the concepts upstream and downstream used here and subsequently are relative concepts considered according to the direction of circulation of the exhaust gases through the catalyst.

[0007] The analysis of the functioning of the catalyst is notably carried out continuously - or in other words in real time - at different operating points of the thermal engine. Such an analysis is carried out by comparing the response of the catalyst to an exhaust gas purification request with a reference nominal response. Depending on the difference obtained between said responses, it is deduced whether the catalyst is functioning correctly by comparing the difference obtained between the responses with a reference threshold.

[0008] Based on the measurements provided by the oxygen sensors, the analysis system identifies a difference in the oxygen content present in the exhaust gases upstream and downstream of the catalyst. If such an analysis reveals an insufficient capacity of the catalyst to effectively treat the exhaust gases, the regulator is then activated.

[0009] For example, we can refer to document FR3058183-B1 (PEUGEOT CITROEN AUTOMOBILES SA) in this regard. According to this document, it is proposed to estimate the temperature of the catalyst and its oxygen storage capacity, from measurements taken by oxygen sensors installed on the exhaust line respectively upstream and downstream of the catalyst. If the estimated temperature of the catalyst is lower than a predefined threshold temperature, the catalyst and / or the exhaust gases to be treated are heated until the catalyst reaches the said threshold temperature. However, the reliability of the analysis of the operation of the catalyst can be difficult to obtain, particularly during transient phases of the operation of the thermal engine. In such cases, analyses carried out while the operation of the thermal engine is unstable may be erroneous.The result of the analysis is then not significantly indicative of the actual capacity of the catalyst to treat exhaust gases.

[0010] This then results in the control-command device learning incorrectly a potentially non-existent failure in the operation of the catalyst, which may be irreversible. This ultimately results in causing inappropriate regulation of the operation of the catalyst. Document US2003024514A1 relates to an air-fuel ratio control device which is capable of assessing a deteriorated state of a catalytic converter to purify an exhaust gas. Presentation of the invention

[0011] Based on the observation which has just been made, the invention aims to overcome the inadequacies of the state of the art concerning the obtaining of relevant regulation in real time of the performance of a catalyst to treat the exhaust gases produced by the thermal engine of a motor vehicle.

[0012] The invention aims more specifically to provide a solution for making the analysis of the operation of the catalyst more reliable and consequently for obtaining relevant regulation of its operation in order to improve its performance. Such a reliable analysis is sought in particular by preventing transient phases of operation of the heat engine from disrupting a correct analysis of the operation of the catalyst.

[0013] To do this, the approach of the invention, which is at least partly based on the previously mentioned observation, is based on the fact that a proportional-integral correction of the measurements provided by the upstream probe makes it possible to boost the correction made, particularly in the case of a significant error detected during the analysis of the operation of the catalyst. Such a correction is carried out by an integrator included in the analysis system. To clarify, the integrator is a logic circuit delivering an output signal proportional to the time integral of an input signal.

[0014] The integrator performs a proportional-integral correction of the measurements provided by the downstream probe, which makes it possible to eliminate a static error detected during the analysis of the operation of the catalyst, in particular in the event of a dispersion in the reliability of the measurements provided by the upstream probe. The dynamic factors for analyzing the operation of the catalyst by the integrator can be defined by analytical models according to various parameters, such as for example a voltage error of the downstream probe, the mass flow rate of the exhaust gases, a catalyst aging factor and / or a downstream voltage setpoint.

[0015] Ideally, on a nominal system when the integrator is activated, a voltage error detected by the upstream probe should be close to 0 (zero). However, activation of the integrator while the upstream regulation is not controlled - or in other words is unstable, such as in the transient phase of operation of the heat engine - can cause a drift in the result provided by the integrator to the catalyst operation regulator. The regulator is in particular - without being exclusive - at least a regulator of the dosage of oxidant and fuel admitted into the heat engine.

[0016] An instability in the measurements provided by the downstream probe then causes discrepancies between detected errors and actual - or in other words real - errors, identifying a failure of the catalyst to treat the exhaust gases. The detected errors are in this case erroneous errors and cause inappropriate regulation of the oxygen richness of the exhaust gases passing through the catalyst.

[0017] It is therefore proposed by the invention to tend towards a convergence of the oxygen richness deduced by the integrator respectively upstream and downstream of the catalyst, by identifying in real time the measurements provided by the downstream probe on the basis of a common - or in other words identical - reference frame with stable measurements provided by the upstream probe. The stability of such measurements over a predefined duration is indicative of a stable operating state of the catalyst favorable to a relevant analysis in real time of its operation and consequently favorable to an adapted regulation of the operation of the catalyst.

[0018] The activation of the integrator is then conditioned at least on a stabilization of the data provided by the upstream probe. This makes it possible to exclude the acquisition by the control-command device of erroneous data relating to non-existent errors in oxygen richness upstream and downstream of the catalyst. As soon as errors detected from the measurements carried out by the upstream probe converge towards an admissible error threshold which is predefined by calibration - in a range of errors close to 0 (zero) - only the binary measurements provided by the downstream probe can be effectively taken into account - on the basis of said error threshold - to identify an effective error requiring regulation of the operation of the catalyst.

[0019] By making the analysis of the catalyst's operation more reliable, a relevant regulation of its operation is obtained. Thus, the performance of the catalyst in treating the exhaust gases prior to their release into the atmosphere is optimized, notwithstanding the transient phases of the thermal engine's operation during which the integrator is deactivated.

[0020] The activation of the integrator is conditioned on the one hand by a first parameter relating to a stabilization of the operating state of the catalyst over a significant stabilization period, and on the other hand by a second parameter relating to said convergence of error of the oxygen richness of the exhaust gases upstream of the catalyst with respect to said reference error threshold.

[0021] It is also proposed to evaluate the stabilization time of the operating state of the catalyst according to a time value which is preferably identified at least by data relating to the mass flow rate of the exhaust gases passing through the catalyst. The aging state of the catalyst is also preferably taken into account to calibrate a gas mass threshold identifying a stable operating state of the catalyst.

[0022] Such a mass flow rate is in particular determined by a gas mass meter, the activation of which is conditioned by the prior identification of the validation of the conditions relating to the first parameter. In other words, the activation conditions of the integrator are applied in series, firstly by validation of the conditions relating to the first parameter and secondly by activation of the gas mass meter dependent on the prior obtaining of the validation of the conditions relating to the first parameter. The invention thus makes it possible to control the performance of the integrator in providing a reliable analysis of the operation of the catalyst to at least one regulator of its operation, in particular a regulator of the oxygen richness contained in the exhaust gases upstream of the catalyst. Such regulation is advantageously carried out at least by controlling the dosage of oxidant and fuel admitted into the heat engine.

[0023] Such reliable analysis is obtained with regard to the precision of the results from the processing of the binary measurements provided by the downstream probe, which are rectified by the integrator in an error range close to zero according to a reference system conforming to - or in other words identical to - that identifying the measurements provided by the upstream probe.

[0024] It should be noted that the invention is simple to implement within a control-command device regulating the oxygen richness present in the exhaust gases downstream of the catalyst based on a regulation of the dosage of oxidant and fuel admitted into the heat engine.

[0025] As described above, the invention relates to a method for real-time regulation of the operation of at least one exhaust gas catalyst produced by a heat engine fitted to a motor vehicle. The method of the invention uses a control-command device comprising a system for real-time analysis of the operation of the catalyst and at least one regulator for air intake into the exhaust gases upstream of the catalyst.

[0026] The implementation of the regulator is subject to an activation order issued by the analysis system in the event of detection of an oxygen richness error in the exhaust gases upstream of the catalyst. Said oxygen error is detected from a logical processing by the analysis system of measurements respectively provided by voltaic oxygen sensors placed on an exhaust gas exhaust line. The oxygen sensors comprise a proportional upstream sensor and a binary downstream sensor respectively placed upstream and downstream of the catalyst.

[0027] According to the invention, said oxygen richness error is identified after a proportional-integral correction of the measurements provided by the downstream probe which is carried out by an integrator which the analysis system comprises. The activation of the integrator is conditioned at least as a dependency of the validation of a first parameter and a second parameter.

[0028] The first parameter relates to an error convergence of the oxygen richness of the exhaust gases measured upstream of the catalyst by the upstream probe with respect to a predefined error threshold. The second parameter relates to a detection of a stable operating state of the catalyst over a predefined period.

[0029] It is understood that said error threshold is included in a range of admissible error values ​​close to a zero value, which is previously defined by calibrating the integrator. As a non-restrictive indication, such a range of admissible error values ​​is of the order between -0.15 V and + 0.15 V (V: volt).

[0030] Other preferred features of the method of the invention are mentioned below. The validation of the second parameter is carried out dependent on the prior validation of the first parameter.

[0031] The said error threshold is entered in a range of admissible error values ​​close to a zero value, which is previously defined by calibrating the integrator.

[0032] The detection of a stable operating state of the catalyst over a predefined period is identified from an evaluation of a mass of exhaust gas passing through the catalyst in a quantity at least equal to a gas mass threshold predefined by calibration.

[0033] The said gas mass threshold is predefined by calibration at least according to the age of the catalyst.

[0034] Said evaluation of a mass of exhaust gas passing through the catalyst is provided by a gas mass meter.

[0035] Activation of the gas mass meter is conditional on the prior obtaining of said convergence of error in the oxygen richness of the exhaust gases upstream of the catalyst in relation to said predefined reference error threshold.

[0036] Said evaluation of a mass of exhaust gas passing through the catalyst can also take into account at least one flow of air and / or fuel admitted into the heat engine.

[0037] In other words, said evaluation of a mass of exhaust gas passing through the catalyst can take into account - in isolation or in combination - either only the flow rate of air admitted into the heat engine, or only the flow rate of fuel admitted into the heat engine. Preferably, the proportion of air and fuel admitted into the heat engine is taken into account.

[0038] The invention also relates to a device for real-time regulation of the operation of at least one exhaust gas catalyst produced by a heat engine fitted to a motor vehicle. The regulation device comprises a control-command device comprising a system for real-time analysis of the operation of the catalyst from measurements provided by said oxygen sensors. The control-command device also comprises at least one regulator - including a regulator of an air intake into the exhaust gases upstream of the catalyst - the implementation of which is dependent on the analysis system.

[0039] According to the invention, said regulation device is configured in accordance with the implementation of a method as just described. For clarification, the analysis system equipping the regulation device generally comprises said integrator carrying out said proportional-integral correction of the measurements provided by the downstream probe prior to the identification of said oxygen richness error in the exhaust gases upstream of the catalyst.

[0040] The invention also relates to a motor vehicle equipped with a propulsion engine comprising at least one heat engine. The vehicle is equipped with an exhaust line for the gases produced by the heat engine incorporating at least one catalyst. The vehicle is equipped with a device for real-time regulation of the operation of said at least one catalyst.

[0041] According to the invention, the regulation device equipping the vehicle conforms to a regulation device as just described.

[0042] The vehicle's propulsion system may be provided exclusively by a thermal engine or be a hybrid propulsion system typically combining a thermal engine and an electric motor.

[0043] To also clarify the real-time concept - particularly considered in relation to the measurements provided by the oxygen sensors, the analysis of the operation of the catalyst and / or the regulation of the operation of the catalyst - the real-time concept is appreciated when the heat engine is in operation and consequently produces exhaust gases which are conveyed to the catalyst via an exhaust line. Presentation of figures

[0044] The invention will be better understood upon reading the following detailed description of an exemplary embodiment of the invention, in relation to the following figures: [ Fig. 1 ] There figure 1 is a diagram illustrating the context of the invention, according to which a control-command system according to the invention regulates the real-time operation of a catalyst for treating exhaust gases produced by a heat engine fitted to a motor vehicle. Said regulation is notably carried out under the control and following a real-time logical analysis of the operation of the catalyst, in order to improve the efficiency of the catalyst in treating the exhaust gases. Fig.2 ] There figure 2 is a diagram illustrating a method according to the invention, making it possible to improve the performance of the catalyst in real time via the control-command system shown in the figure 1 . [ Fig.3 ] There figure 3is a first diagram illustrating for example the risk of a potential fault in analyzing the real-time operation of a catalyst for treating exhaust gases produced by a heat engine fitted to a motor vehicle, which the invention seeks to avoid. Fig.4 ] There figure 4 is a second diagram illustrating - by comparison with the first diagram shown on the figure 3 - the result obtained by applying the method of the invention shown diagrammatically for example on the figure 1 and the figure 2 , which prevents the logical analysis obtained from the operation of the catalyst from being erroneous. Detailed description of the invention

[0045] The figures and their detailed, non-limiting descriptions set out the invention in particular ways that are not restrictive as to its scope. The figures and their detailed descriptions of an exemplary embodiment of the invention may serve to better define it, if necessary in relation to the general description which has just been given. Furthermore, to avoid overloading the figures and thus facilitate their reading, the reference numbers assigned to the terms and / or concepts used to describe the invention and indicated in any one of the figures are potentially repeated in the description of any other figure without implying their presence in all of the figures.

[0046] On the figure 1, a vehicle whose propulsion engine is at least provided by a heat engine 1 emits exhaust gases G1 which must be treated prior to their release into the atmosphere. The exhaust gases G1 are produced by the heat engine 1 which is supplied with oxidant C1 - air in particular - and with fuel C2 - hydrocarbons in particular. According to the example illustrated, the propulsion engine of the vehicle can be equipped with a turbocharger 2 providing, if necessary, supercharging of the heat engine 1 with oxidant C1.

[0047] The exhaust gases G1 are routed to the outside of the vehicle via an exhaust line 3 incorporating a catalyst 4. The catalyst 4 is a device for treating the exhaust gases G1 by oxidation-reduction of the toxic chemical agents they contain, such as carbon monoxide (CO), nitrogen oxide (NOx) and unburned hydrocarbons (HC).

[0048] To certify that the exhaust gases G1 discharged into the atmosphere are purified in accordance with the regulations, a control-command device 6 on board the vehicle regulates the operation of the catalyst 4 in real time when the heat engine 1 is in operation. The control-command device 6 comprises in particular an analysis system 5 and at least one regulator, including a regulator 7 of the dosage of air C1 and / or fuel C2 admitted into the heat engine 1.

[0049] The regulator 7 is in particular configured to regulate the oxygen richness present in the exhaust gases G1 discharged from the heat engine 1 inside the exhaust line 3. The oxygen regulation operated by the regulator 7 is identified by an activation order 5a which is generated by the analysis system 5 and which is transmitted to the regulator 7 in order to obtain optimal treatment of the exhaust gases G1.

[0050] The activation order 5a is generated by the analysis system 5, in the event of detection of an oxygen richness error in the exhaust gases G1 upstream of the catalyst 4. Such an oxygen richness error is likely to affect the capacity of the catalyst 4 to effectively treat the exhaust gases G1 to reduce the content of toxic chemical agents that they contain before their release into the atmosphere.

[0051] For this purpose, the analysis system 5 uses voltaic measurements M1, M2 which are provided by oxygen probes 8a, 8b placed on the exhaust line 3 on either side of the catalyst 4. The oxygen probes 8a, 8b comprise an upstream probe 8a and a downstream probe 8b, which are placed on the exhaust line 3 respectively upstream and downstream of the catalyst 4 in the direction S1 of circulation of the exhaust gases G1 through the catalyst 4.

[0052] The upstream probe 8a provides proportional M1 measurements and the downstream probe 8b provides binary M2 measurements. An analysis of the operating state of the catalyst 4 is then carried out via the analysis system 5, at least from a logical processing of the measurements M1, M2 by the analysis system 5. The logical processing of the measurements M1, M2 by the analysis system 5 makes it possible to identify a possible oxygen error upstream of the catalyst 4 and consequently to generate, if necessary, the activation order 5a of the regulator 7. The logical processing of the measurements M1, M2 carried out by the analysis system 5 uses an integrator 10, which performs a proportional-integral correction of the measurements M1 provided by the downstream probe 8b.

[0053] However, there remains a risk that the oxygen error identified by the integrator 10 is imprecise and / or incorrect, in particular depending on the different operating phases of the heat engine 1 which can also vary rapidly. Indeed, the supply of air C1 and / or fuel C2 in the heat engine 1 is adapted according to the operating phase of the heat engine 1, to the detriment of operating stability of the catalyst 4.

[0054] For illustration purposes, it is shown for example on the diagrams of the figure 3 and of the figure 4a Cartesian reference indicating - over a nominal analysis cycle - the results obtained on the distribution of a richness error detected downstream of catalyst 4 during activation of the proportional integral correction carried out by integrator 10. The voltage errors of the M2 measurements provided by the downstream probe 8b are shown on the abscissa and the distribution of the oxygen errors detected to the detriment of the performance of catalyst 4 is shown on the ordinate.

[0055] It appears on the figure 3 - which relates to the result obtained in the absence of the application of the present invention - that oxygen errors are detected on the ordinate while the voltage errors of the M2 measurements provided by the downstream probe 8b - indicated on the abscissa - are far from a zero voltage error by being detected between minus 0.2 V and plus 0.5 V. However, a detected and corrected voltage error should be close to 0 (zero) when the integrator 10 is activated.

[0056] The invention therefore proposes a solution to overcome obtaining an analysis of the operation of the catalyst 4 which would be erroneous on the basis of such non-existent voltage errors illustrated in the figure 3 , because they are far from a zero voltage error (0: zero) despite their correction by the integrator 10.

[0057] To do this on the figure 1 and the figure 2 , the analysis system 5 of the invention integrates an activation module 11 of the integrator 10, as detailed for example in the figure 2 The activation module 11 of the integrator 10 generates an activation instruction DV of the integrator 10, subject to the validation of two parameters P1, P2.

[0058] A first parameter P1 relates to an error convergence PE1 of the oxygen richness of the exhaust gases G1 measured by the upstream probe 8a with respect to a reference error threshold PS1 predefined by calibration. A second parameter P2 relates to a detection of a stable operating state of the catalyst 4 over a predefined duration. Concerning the first parameter P1, the error convergence PE1 of the oxygen richness of the exhaust gases G1 takes into account the evaluation of an error PE1 of oxygen richness with respect to said error threshold PS1, in a range of admissible error values ​​which is previously defined by calibration of the integrator 10. At the end of such an evaluation, a first data item D1 relating to the activation of the integrator 10 is emitted.

[0059] In the case where the PE1 oxygen richness errors detected by the upstream probe 8a do not converge towards the error threshold PS1, a first value of the first data item D1 relates to a prohibition of activation of the integrator 10. Conversely, when the PE1 oxygen richness errors detected by the upstream probe 8a converge towards the error threshold PS1, a second value of the first data item D1 relates to an authorization of activation of the integrator 10.

[0060] Concerning the second parameter P2, a gas mass counter 12 evaluates a mass of exhaust gas G1 passing through the catalyst 4 over a predefined duration. Such a gas mass evaluation makes it possible to identify a time value of stability of the operating state of the catalyst 4.

[0061] The implementation of the gas mass counter 12 is conditioned on the generation of the second value of the first data D1 authorizing an activation of the integrator 10. This provides a joint validation of the first parameter P1 and the second parameter P2 conditioning the effective activation of the integrator 10. More specifically, a validation of the effective activation of the integrator 10 is emitted in series, firstly by validation of the first parameter P1 then by validation of the second parameter P2, the activation of the gas mass counter 12 being effective as soon as the first parameter P1 is previously validated.

[0062] According to the example illustrated, the evaluation carried out by the gas mass meter 12 takes into account the flow rate DC1 of oxidant C1 admitted into the heat engine 1. The mass of gas evaluated by the gas mass meter 12 is compared to a gas mass threshold S2 which is predefined according to the age 9 of the catalyst 4, the age 9 of the catalyst being a determining factor in the capacity of the catalyst 4 to effectively treat the exhaust gases G1 prior to their release into the atmosphere.

[0063] Following the comparison between the gaseous mass evaluated by the gaseous mass counter 12 and said gaseous mass threshold S2, a second data item D2 relating to the effective activation or not of the integrator 10 is emitted.

[0064] It is recalled here that the implementation of the gas mass counter 12 is subject to the emission of a value of the first data D1 validating the activation of the integrator 10. Thus, the generation of a validation instruction DV of the activation of the integrator 10 is generated by successively validating in series the first parameter P1 and the second parameter P2.

[0065] In other words, in the case where the evaluated gaseous mass does not reach said gaseous mass threshold S2 in real time - preferably taking into account the obsolescence 9 of the catalyst 4, a first value of the second data item D2 relates to a prohibition of activation of the integrator 10. Conversely, when the evaluated gaseous mass reaches said gaseous mass threshold S2, the stable operating state of the catalyst 4 is validated. A second value of the second data item D2 relating to an authorization of activation of the integrator 10 then generates said validation instruction DV of the activation of the integrator 10. Following the logical analysis of the measurements M1, M2 provided by the oxygen probes 8a, 8b - at least including the processing by the integrator 10 of the measurement M1 provided by the downstream probe 8a - the activation order 5a of the regulator 7 is generated by the analysis system 5.The regulator 7 then corrects the oxygen richness of the exhaust gases downstream of the catalyst 4, in accordance with the activation order 5a of the catalyst 4 emitted by the analysis system 5.

[0066] On the figure 4 the result of the oxygen errors detected after application of a method of the invention is represented for example in a continuous line, in comparison with the result obtained on the figure 3 which is reproduced on the figure 4 in broken line.

[0067] It appears on the figure 4that the oxygen errors shown in solid lines are detected on the ordinate while the voltage errors of the measurements M1 provided by the downstream probe 8b - indicated on the abscissa - are close to a zero voltage error by being detected between substantially minus 0.15 V and plus 0.05 V. By applying a method according to the invention, there emerges an improvement in the relevance of the oxygen errors detected by the downstream probe 8b which condition the implementation of the regulator 7 to increase the performance of the catalyst 4 to effectively treat the exhaust gases G1. According to the needs identified by the analysis system 5 on the operating state of the catalyst 4, the regulator 7 controls - in accordance with the activation order 5a which it receives - a supply of fuel C2 and / or air C1 in the heat engine 1. The supply of air C1 in the heat engine 1 can, if necessary, be carried out via the turbocharger 2 as illustrated in the figure 1 .

[0068] Such regulation makes it possible to measure the quantity of oxygen present in the exhaust gases G1 at the outlet of the heat engine 1, according to the oxygen error identified by the analysis system 5 which is corrected by the integrator 10 whose implementation is controlled by the activation module 11. The relevance obtained from the oxygen error thus makes it possible to optimize the capacity of the catalyst 4 to purify the exhaust gases G1 of the toxic agents which they convey.

Claims

1. Method for real-time regulation of the operation of at least one catalyst (4) of exhaust gases (G1) produced by a heat engine (1) equipping a motor vehicle, the method implementing a control-command device (6) comprising a system (5) for analyzing in real time the operation of the catalyst (4) and at least one regulator (7) of an air intake into the exhaust gases (G1) upstream of the catalyst (4), the implementation of the regulator (7) being placed under dependence on an activation order (5a) emitted by the analysis system (5) in the event of detection of an oxygen richness error in the exhaust gases (G1) upstream of the catalyst (4), said oxygen error being detected from a logical processing by the analysis system (5) of measurements (M1, M2) respectively provided by voltaic oxygen probes (8a, 8b) placed on an exhaust line (3) of the exhaust gases (G1), including a proportional upstream probe (8a) and a binary downstream probe (8b) respectively placed upstream and downstream of the catalyst (4), characterized: in that said oxygen richness error is identified after a proportional-integral correction of the measurements (M1) provided by the downstream probe (8b) which is carried out by an integrator (10) which the analysis system (5) comprises, and in that the activation of the integrator (10) is conditioned at least as a dependency of the validation: - ) of a first parameter (P1) relating to an error convergence (PE1) of the oxygen richness of the exhaust gases (G1) measured upstream of the catalyst (4) by the upstream probe (8a) with respect to a predefined error threshold (PS1), and - ) of a second parameter (P2) relating to a detection of a stable operating state of the catalyst (4) over a predefined duration.

2. Method according to claim 1, characterized in that the validation of the second parameter (P2) is carried out dependent on the prior validation of the first parameter (P1).

3. Method according to any one of claims 1 and 2, characterized in that said error threshold (PS1) is entered in a range of admissible error values close to a zero value, which is previously defined by calibrating the integrator (10).

4. Method according to any one of claims 1 to 3, characterized in that the detection of a stable operating state of the catalyst (4) over a predefined duration is identified from an evaluation of a mass of exhaust gas (G1) passing through the catalyst (4) in a quantity at least equal to a gas mass threshold (S2) predefined by calibration.

5. Method according to claim 4, characterized in that said gas mass threshold (S2) is predefined by calibration at least according to the age (9) of the catalyst (4).

6. Method according to any one of claims 4 and 5, characterized in that said evaluation of a mass of exhaust gas (G1) passing through the catalyst (4) is provided by a gas mass counter (12).

7. Method according to claim 6, characterized in that the activation of the gas mass counter (12) is conditioned on the prior obtaining of said error convergence (PE1) of the oxygen richness of the exhaust gases (G1) upstream of the catalyst (4) relative to said predefined reference error threshold (PS1).

8. Method according to any one of claims 4 to 7, characterized in that said evaluation of a mass of exhaust gas (G1) passing through the catalyst (4) takes into account at least one flow rate (DC1) of air (C1) and / or fuel (C2) admitted into the heat engine (1).

9. Device for real-time regulation of the operation of at least one catalyst (4) of exhaust gases (G1) produced by a heat engine (1) equipping a motor vehicle, the regulation device comprising a control-command device (6) comprising a system (5) for real-time analysis of the operation of the catalyst (4) from measurements (M1, M2) provided by said oxygen probes (8a, 8b), and comprising at least one regulator (7) of an air intake into the exhaust gases (G1) upstream of the catalyst (4) the implementation of which is placed under dependence of the analysis system (5), characterized in that said regulation device is configured in accordance with the implementation of a method according to any one of claims 1 to 8.

10. Motor vehicle equipped with a propulsion engine comprising at least one heat engine (1) and equipped with an exhaust line (3) for the gases produced by the heat engine (1) incorporating at least one catalyst (4), the vehicle being equipped with a device for real-time regulation of the operation of said at least one catalyst (4), characterized in that the regulation device equipping the vehicle conforms to a regulation device (5) according to claim 9.