Computer for probe clogging diagnosis of a vehicle

Abstract

The present invention relates to a computer (50) for a vehicle (1) comprising a heat engine (10), a pollution abatement system (20) configured to abate pollution from exhaust gases of the heat engine, a first probe (30) disposed between an outlet of the heat engine and an inlet of the pollution abatement system and configured to measure a first parameter related to an oxygen content in the exhaust gases at the outlet of the heat engine, a second probe (40) disposed at an outlet of the pollution abatement system and configured to measure a second parameter related to an oxygen content in the exhaust gases at the outlet of the pollution abatement system, the computer being configured to receive values measured by the first probe and by the second probe over a predefined measurement time interval and to diagnose a clogging of the first probe.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of vehicles equipped with a heat engine, and more particularly to a computer for probe clogging diagnosis, the probe being configured to measure the amount of oxygen at the outlet of the heat engine of the vehicle. BACKGROUND

[0002] It is known for the heat engine of a vehicle to be connected to an exhaust line, in particular making it possible to evacuate the exhaust gases emitted during the combustion phase of the heat engine via the exhaust pipe. Furthermore, the exhaust line comprises a pollution elimination system, which makes it possible to reduce the pollution of the exhaust gases before evacuating the exhaust gases emitted by the heat engine.

[0003] Furthermore, a probe is installed between the outlet of the heat engine and the inlet of the pollution elimination system, which makes it possible to measure, among other things, the oxygen content in the exhaust gases.

[0004] It is also known for the vehicle to comprise an engine control unit, which makes it possible to control the various actuators of the heat engine, in particular the injectors, the intake throttle, etc. The control unit determines the amount of fuel to be injected into the heat engine based on the oxygen content measured by the probe, so that the ratio between the amount of fuel and the amount of air during the combustion phase of the heat engine is optimal to ensure maximum efficiency of the heat engine.

[0005] Furthermore, the probe also makes it possible to provide the engine control unit with information on the level of pollutants contained in the exhaust gases.

[0006] However, during the combustion of a mixture of air and fuel by the engine, when this mixture contains more fuel than is necessary, it is possible for soot to deposit on the probe, thus causing the oxygen probe to clog, or else to be damaged.

[0007] When the probe is clogged, it can make erroneous measurements, in which case the engine control unit can determine an erroneous amount of fuel to be injected.

[0008] Furthermore, when the probe is clogged, it can no longer be possible to make measurements.

[0009] The engine control unit is able to detect this probe malfunction and to advise the user of the vehicle to replace the oxygen probe. However, the clogging of the probe is temporary in nature. Indeed, the probe can be descaled in a few tens of minutes, in particular when the heat engine is running at high speed, in other words when the flow rate and the temperature of the gases in the heat engine are high.

[0010] Therefore, if the user of the vehicle follows the advice given by the engine control unit and decides to replace the probe or to carry out a replacement of the probe, this generates costs, in particular the cost of the new probe or the cost of the assembly of the new probe, which could have been avoided.

[0011] Therefore, there is a need for a solution that enables at least partial resolution of these drawbacks. SUMMARY

[0012] The present invention relates to a computer for a vehicle, said vehicle comprising:

[0013] - a heat engine,

[0014] - a pollution abatement system in fluid communication with the engine and configured to abate pollution originating from exhaust gases of said engine,

[0015] - a first probe arranged between the outlet of the engine and the inlet of the pollution abatement system and configured to measure a first parameter related to the amount of oxygen in the exhaust gases at the outlet of the engine,

[0016] - a second probe arranged at the outlet of the pollution abatement system and configured to measure a second parameter related to the amount of oxygen in the exhaust gases at the outlet of the pollution abatement system,

[0017] said computer being configured to communicate with the first probe and the second probe, said computer comprising a storage area in which a predetermined counter value is recorded, said computer being configured to:

[0018] - receive values measured by the first probe and the second probe over a predefined measurement time interval,

[0019] - determine a variation of a first air coefficient over the predefined measurement time interval based on the values received from the first probe and a variation of a second air coefficient over the predefined measurement time interval based on the values received from the second probe, the first air coefficient and the second air coefficient being defined as the ratio of the mass of air introduced in the heat engine and the mass of air introduced corresponding to the theoretical air mass demand for the complete combustion of a predefined fuel quantity injected into the heat engine,

[0020] - calculate an integral between the variation of the first coefficient and the variation of the second coefficient over a calculation time interval comprised in the predefined measurement time interval,

[0021] - determine whether the calculated integral is comprised in a predefined reference average value interval or outside said predefined reference average value interval,

[0022] - decrement the counter when the calculated integral is comprised in the predefined reference average value interval,

[0023] - incrementing a counter when the computed integral is outside a predefined reference average interval,

[0024] - diagnosing a first probe clogging when the value of the counter is equal to a predefined counter threshold.

[0025] The computer thus makes it possible to quickly detect a clogging of the first probe. Moreover, the computer thus makes it possible to distinguish between a definitive failure of the first probe, in particular due to the aging of the first probe, and a temporary clogging of the first probe.

[0026] Preferably, the computer is configured to trigger a descaling operation of the first probe when it diagnoses a clogging of the first probe.

[0027] The computer thus makes it possible to detect a descaling and implement a remediation of the clogging of the first probe.

[0028] Preferably, the computer is configured to calculate an average value between the computed integral value and a predetermined average value when the computed integral is included in a predefined reference average interval.

[0029] The computer thus makes it possible to update the average value based on the computed integral value.

[0030] Still preferably, the computer is configured to record the computed average value in its memory area.

[0031] The last value of the computed average value is thus conserved for a subsequent use by the computer, in particular after the next integral calculation.

[0032] Still preferably, the computer is configured to reinitialize the value of the counter when it diagnoses a clogging of the first probe.

[0033] Advantageously, the computer is configured to, before determining the variation of the first air coefficient and the variation of the second air coefficient, apply a first correction factor to each value received by the computer and measured by the first probe and a second correction factor to each value received by the computer and measured by the second probe.

[0034] The first correction factor and the second correction factor make it possible in particular to correct measurement errors that can exist.

[0035] Still preferably, the computer is configured to record the applied first correction factor and the applied second correction factor when the computed integral is included in a predefined reference average interval.

[0036] The first correction factor and the second correction factor are thus conserved when the first probe is operating correctly, making it possible to use these values again subsequently.

[0037] Preferably, the measurement time interval is defined between a first time instant, defined as the time instant at which the fuel injection in the heat engine stops, and a second time instant, defined as the time instant at which at least one of the values measured by the first probe and by the second probe is equal to a predefined maximum threshold value.

[0038] Still preferably, the calculation time interval is defined between a first time instant, defined as the time instant at which the fuel injection in the heat engine stops, and a third time instant, defined as the time instant at which the value measured by at least one of the second probes starts to be greater than or equal to the value measured by the first probe.

[0039] The present application also relates to a vehicle comprising:

[0040] - a heat engine,

[0041] - a pollution abatement system in fluid communication with the engine and configured to abate pollution originating from the exhaust gases of said engine,

[0042] - a first probe arranged between the outlet of the engine and the inlet of the pollution abatement system and configured to measure a first parameter related to the oxygen content in the exhaust gases at the outlet of the engine,

[0043] - a second probe arranged at the outlet of the pollution abatement system and configured to measure a second parameter related to the oxygen content in the exhaust gases at the outlet of the pollution abatement system,

[0044] - a computer as previously described.

[0045] The present application also relates to a method for diagnosing a clogging of the first probe of a vehicle according to the present application, comprising the steps of:

[0046] - measuring, by the first probe, the first parameter and measuring, by the second probe, the second parameter, during a predefined measurement time interval,

[0047] - determining the variation of a first air coefficient over the predefined measurement time interval based on the values received from the first probe and determining the variation of a second air coefficient over the predefined measurement time interval based on the values received from the second probe, the first air coefficient and the second air coefficient being defined as the ratio of the mass of introduced air in the heat engine to the mass of introduced air corresponding to the theoretical air demand for the complete combustion of a predefined fuel quantity injected into the heat engine,

[0048] - calculating the integral between the variation of the first coefficient and the variation of the second coefficient over a calculation time interval comprised in the predefined measurement time interval,

[0049] - when the calculated integral is comprised in a predefined reference average value interval, decrementing a counter,

[0050] - when the calculated integral is outside the predefined reference average value interval, incrementing the counter,

[0051] - diagnosing a first probe clogging when the value of the counter is equal to a predefined counter threshold.

[0052] The present application also relates to a computer program product, characterized in that it comprises a set of program code instructions which, when executed by one or more processors, configure the one or more processors to implement the method as previously described. BRIEF DESCRIPTION OF DRAWINGS

[0053] Other features and advantages of the present application will become more apparent from the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings wherein:

[0054] Figure 1 An embodiment of a vehicle according to the present application is schematically illustrated;

[0055] Figure 2 A first example of values of a first parameter measured by a first probe and of values of a second parameter measured by a second probe as a function of time is illustrated when the first probe is operating correctly;

[0056] Figure 3 A second example of values of a first parameter measured by a first probe and of values of a second parameter measured by a second probe as a function of time is illustrated when the first probe is clogged;

[0057] Figure 4 An embodiment of a method according to the present application is illustrated. DETAILED DESCRIPTION

[0058] Vehicle

[0059] Reference Figure 1 An embodiment of a vehicle 1 according to the present application will now be described.

[0060] The vehicle 1 is known to comprise a thermal engine 10, a pollution elimination system 20, a first probe 30, at least one second probe 40 and a computer 50.

[0061] The thermal engine 10 is known to make it possible to ensure the movement of the vehicle 1. To this end, the thermal engine 10 generates mechanical energy from a mixture of fuel and air, more particularly from the combustion of a mixture of fuel and air. This combustion also generates exhaust gases, comprising in particular carbon dioxide, water, oxygen molecules, nitrogen, carbon monoxide, hydrocarbons and nitrogen oxides.

[0062] The pollution elimination system 20 is in fluid communication with the heat engine 10. More particularly, the pollution elimination system 20 is connected to the heat engine 10 via a pipe, in particular a tubular pipe, so that the exhaust gases emitted by the heat engine 10 can go into the pollution elimination system 20.

[0063] The pollution elimination system 20 is configured to eliminate the pollution of the exhaust gases emitted by the heat engine 10, in other words to transform the polluting gases, in particular the carbon monoxide, the hydrocarbons or the nitrogen oxides included in the exhaust gases, into gases that are harmless to the environment.

[0064] To this end, the pollution elimination system 20 can notably comprise a particulate filter. As its name indicates, the particulate filter makes it possible to filter out the particles emitted in the exhaust gases, so that these particles are not emitted into the environment of the vehicle 1.

[0065] The pollution elimination system 20 can also comprise other systems, such as a so-called RCS (“réduction catalytique sélective”, selective catalytic reduction) module and an oxidation catalyst.

[0066] The RCS module known to the person skilled in the art notably makes it possible to reduce the quantity of nitrogen oxides contained in the exhaust gases. The oxidation catalyst makes it possible to transform the carbon monoxide and the hydrocarbons present in the exhaust gases into substances that are harmless to the environment of the vehicle 1 by an oxidation method.

[0067] The first probe 30 is positioned between the outlet of the heat engine 10 and the inlet of the pollution elimination system 20. More particularly, the first probe 30 is positioned on the tubular pipe connecting the heat engine 10 and the pollution elimination system 20.

[0068] More particularly, the first probe 30 is positioned between the outlet of the heat engine 10 and the inlet of the particulate filter of the pollution elimination system 20.

[0069] The first probe 30 can be, for example, a probe known to the person skilled in the art called “oxygen probe” or “lambda probe” or “upstream probe”.

[0070] The first probe 30 can also be a probe known to the person skilled in the art called “NOX probe”.

[0071] More particularly, the first probe 30 comprises a pumping unit. The first probe 30 is in fluid communication with the pipe connecting the heat engine 10 and the pollution elimination system 20 via said pumping unit. In other words, the exhaust gases flowing between the heat engine 10 and the pollution elimination system 20 also flow through the pumping unit of the first probe 30.

[0072] The first probe 30 is configured to measure a first parameter related to the oxygen content in the exhaust gas at the outlet of the heat engine 10, in particular a first parameter related to the oxygen content in the exhaust gas flowing from the heat engine 10 to the pollution elimination system 20 via the duct. The oxygen content in the exhaust gas also enables to determine the oxygen concentration in the exhaust gas.

[0073] The first parameter corresponds in particular to a so-called "pumping current". The pumping current represents the current supplied to the pumping unit when the exhaust gas flows through the pumping unit. More specifically, the pumping current is due to the movement of oxygen in the pumping unit, and more specifically, to the movement of oxygen ions of the exhaust gas.

[0074] The pumping current represents in particular the difference between the oxygen content in the exhaust gas and a reference oxygen content emitted in the exhaust gas by the heat engine 10 after having combusted a mixture of air and fuel, wherein the amount of air is a sufficient amount necessary for the fuel to be completely combusted.

[0075] The first probe 30 is also configured to send at least one measured value of the first parameter related to the oxygen content to the computer 50 through a first communication link. The first communication link is in particular a CAN (for "Controller Area Network" in English) data bus.

[0076] In addition, the first probe 30 is configured to send to the computer 50 an identifier associated with each sent measured value, so that the computer 50 determines that the measured value is sent from said first probe 30.

[0077] The second probe 40 is arranged at the outlet of the pollution elimination system 20. More specifically, the second probe 40 is arranged on the second duct, in particular the tubular duct, which enables the pollution-eliminated exhaust gas from the pollution elimination system 20 to be discharged outside the pollution elimination system 20. More specifically, the second probe 40 is arranged on the second duct at the outlet of the particulate filter of the pollution elimination system 20.

[0078] The second probe 40 can be for example a probe known to the person skilled in the art as an "oxygen probe" or a "lambda probe" or an "upstream probe".

[0079] The second probe 40 can also be a probe known to the person skilled in the art as a "NOx probe".

[0080] More specifically, the second probe 40 comprises a second pumping unit. The second probe 40 is in fluid communication with the second duct via said second pumping unit. In other words, the pollution-eliminated exhaust gas leaving the pollution elimination system 20 also flows through the second pumping unit of the second probe 40.

[0081] The second probe 40 is configured to measure a second parameter related to the oxygen content in the exhaust gas at the outlet of the pollution abatement system 20, and in particular a second parameter related to the oxygen content in the exhaust gas discharged from the pollution abatement system 20 via the second conduit.

[0082] The second parameter corresponds in particular to a so-called "second pumping current". The second pumping current represents the current supplied to the second pumping unit when the exhaust gas flows through the second pumping unit. More specifically, the second pumping current is due to the movement of oxygen in the pumping unit, and more specifically, to the movement of oxygen ions of the exhaust gas.

[0083] The second pumping current also represents the difference between the oxygen content in the exhaust gas and the reference oxygen content.

[0084] The second probe 40 is also configured to send at least one measured value of the second parameter related to the oxygen content to the computer 50 through a second communication link. The second communication link is in particular a CAN (for "Controller Area Network" in English) data bus.

[0085] Furthermore, the second probe 40 is configured to send to the computer 50 an identifier associated with each sent measured value, so that the computer 50 determines that the measured value is sent from said second probe 40.

[0086] Reference is made to Figure 2 , which shows a first example of the variation of the measured values of the first parameter P1 and of the second parameter P2 as a function of time t when the first probe 30 is functioning normally, in other words correctly. Figure 3 Reference is made to

[0087] The computer 50 is configured to communicate with the first probe 30 via a first communication link and with the second probe 40 via a second communication link.

[0088] The computer 50 comprises a storage zone in which are recorded predetermined counter values and predetermined average values.

[0089] The computer 50 is configured to receive, in particular continuously, the values measured by the first probe 30 and by the second probe 40, respectively, and the identifiers associated with each measured value, respectively, via said first communication link and via said second communication link.

[0090] More specifically, reference is made to Figure 2 and Figure 3In particular, the computer 50 is configured to select, from the received values, the values measured by the first probe 30 and by the second probe 40 in a measurement time interval defined between a first time instant tl and a second time instant t2.

[0091] The first time instant tl is defined as the time instant at which the fuel injection in the heat engine 10 is stopped, in particular when the accelerator of the vehicle 1 is not actuated by the driver. For example, if the accelerator is an acceleration pedal, the injection stop means that the driver does not exert any pressure on the acceleration pedal.

[0092] The second time instant t2 is defined as the time instant at which the first probe 30 and the second probe 40 start measuring at least one value equal to a predefined maximum threshold value. The maximum threshold value is defined, in particular, by the manufacturer as a value equal to the second parameter P2, or to the first parameter PI, corresponding to an oxygen amount close to that contained in pure air.

[0093] In particular, the computer 50 is configured to determine the first time instant tl and the second time instant t2 in order to define the measurement time interval to be considered.

[0094] In order to determine the first time instant tl, the computer 50 can be connected to a computer of the heat engine 10, which is able to control the various actuators of the heat engine 10, in particular the injectors, the intake throttle, etc. According to this example, the computer 50 determines the first time instant tl by receiving information indicating the injection stop sent by the engine computer.

[0095] According to another example, the computer 50 is connected to the accelerator and is configured to detect when the accelerator is not activated.

[0096] In order to determine the second time instant t2, the computer 50 compares the values measured by the first probe 30 and by the second probe 40 with a predefined maximum threshold value and detects the second time instant t2 when at least one value equal to the predefined maximum threshold value is measured by the first probe 30 and by the second probe 40.

[0097] Moreover, based on the identifier associated with each value measured by the first probe 30 and by the second probe 40, respectively, the computer 50 is configured to identify whether the measured value is sent by the first probe 30 or by the second probe 40.

[0098] The computer 50 is further configured to apply a predefined first correction factor to each reception value measured by the first probe 30 and to apply a predefined second correction factor to each reception value measured by the second probe 40. To this end, the computer 50 adds the value of the first correction factor to each reception value measured by the first probe 30 and the computer 50 adds the value of the second correction factor to each reception value measured by the second probe 40.

[0099] The first correction factor and the second correction factor are in particular predefined by the computer 50 itself in order to adjust potential measurement errors made by the first probe 30 and / or by the second probe 40 according to the environment. For example, the first correction factor (or the second correction factor) enables the reception values measured by the first probe 30 (or by the second probe 40) to be recentered around a nominal value corresponding to said first probe 30 (or to said second probe 40).

[0100] The value of the first correction factor and the value of the second correction factor are in particular recorded in a memory area of the computer 50. The first correction factor and the second correction factor can correspond to the same value.

[0101] In addition, a predefined correspondence table is recorded in a memory area of the computer 50. This correspondence table comprises, for each value of the first parameter PI - in other words, for each value of the first pumping current - an associated first air coefficient value. In addition, this correspondence table comprises, for each value of the second parameter P2 - in other words, for each value of the second pumping current - an associated second air coefficient value.

[0102] The first air coefficient and the second air coefficient are defined as the ratio of the mass of introduced air in the heat engine 10 and the mass of introduced air corresponding to the theoretical air requirement for the complete combustion of a predefined quantity of fuel injected into the heat engine 10.

[0103] In addition, the computer 50 is further configured to determine the variation of the first air coefficient over a predefined measurement time interval on the basis of the reception values measured by the first probe 30 to which the computer 50 has applied the first correction factor and on the basis of the correspondence table. Similarly, the computer 50 is configured to determine the variation of the second air coefficient over a predefined measurement time interval on the basis of the reception values measured by the second probe 40 to which the computer 50 has applied the second correction factor and on the basis of the correspondence table.

[0104] For example, when the first pumping current is positive or its value is relatively high, the value of the first coefficient is greater than 1. This means that the mixture of air and fuel injected into the heat engine 10 comprises, before the mixture is combusted, an air mass greater than the introduced air mass corresponding to the theoretical air mass demand for complete combustion of the amount of fuel injected into the heat engine 10. The mixture of air and fuel previously injected into the heat engine 10 is then called a lean mixture. When the first pumping current is positive, the value of the first coefficient is greater than 1.

[0105] Conversely, when the first pumping current is negative or its value is relatively low, the value of the first coefficient is less than 1. This means that the mixture of air and fuel injected into the heat engine 10 comprises, before the mixture is combusted, an air mass less than the introduced air mass corresponding to the theoretical air mass demand for complete combustion of the amount of fuel injected into the heat engine 10. The mixture of air and fuel previously injected into the heat engine 10 is then called a rich mixture.

[0106] The computer 50 is also configured to calculate an integral between the variation of the first coefficient and the variation of the second coefficient over a calculation time interval comprised in a predefined measurement time interval.

[0107] With reference to Figure 2 and Figure 3 , the calculation time interval is defined between a first time instant ti and a third time instant t3, the third time instant t3 being defined as the time instant at which each value of the second parameter P2 measured by the second probe 40 is greater than or equal to the value of the first parameter Pi measured by the first probe 30.

[0108] In a first example illustrated in Figure 2 , the third time instant t3 coincides with the second time instant t2. In a second example illustrated in Figure 3 , the third time instant t3 is different from the second time instant t2, in particular less than the second time instant t2. Thus, the integral calculated by the computer 50 on the basis of the values of the first parameter Pi and of the second parameter P2 illustrated in Figure 3 is less than the integral calculated by the computer 50 on the basis of the values of the first parameter Pi and of the second parameter P2 illustrated in Figure 2 .

[0109] The computer 50 is also configured to determine whether the calculated integral is comprised in a predefined reference average value interval or outside said predefined reference average value interval.

[0110] The reference average value interval is in particular predefined by the computer 50, for example at the start of the operation of the vehicle 1. The reference average value interval can also correspond to a rating.

[0111] The reference average value interval can be defined in accordance with a predetermined average value recorded in the storage area. For example, the maximum value of the reference average value interval corresponds to the recorded average value plus a value of a predefined first threshold. As another example, the minimum value of the reference average value interval corresponds to the recorded average value minus a value of a predefined second threshold. The first threshold and the second threshold can correspond to the same value.

[0112] In particular, the computed integral of the first example shown is comprised in the predefined reference average value interval. In contrast thereto, the computed integral related to the second example shown is outside the predefined reference average value interval, in particular because the value of the computed integral related to the second example is small and smaller than the minimum value of the reference average value interval. Figure 2 The computed integral of the first example shown is comprised in the predefined reference average value interval. In contrast thereto, the computed integral related to the second example shown is outside the predefined reference average value interval, in particular because the value of the computed integral related to the second example is small and smaller than the minimum value of the reference average value interval. Figure 3 The computed integral of the first example shown is comprised in the predefined reference average value interval. In contrast thereto, the computed integral related to the second example shown is outside the predefined reference average value interval, in particular because the value of the computed integral related to the second example is small and smaller than the minimum value of the reference average value interval.

[0113] The computer 50 is further configured to calculate an average value between the value of the computed integral and the predetermined average value when the computed integral is comprised in the predefined reference average value interval.

[0114] Furthermore, the computer 50 is further configured to record the computed average value in the storage area as a replacement for the predetermined average value.

[0115] The computer 50 is further configured to decrement a counter recorded in the storage area when the computed integral is comprised in the predefined reference average value interval. For example, the computer 50 decrements the value of the counter recorded in the storage area by 1.

[0116] Furthermore, the computer 50 is further configured to record in its storage area the first correction factor previously applied to the at least one measured value of the first parameter PI when the computed integral is comprised in the predefined reference average value interval. Similarly, the computer 50 is further configured to record in its storage area the second correction factor previously applied to the at least one measured value of the second parameter P2. Thus, the recorded values of the first and second factors can be used again subsequently when subsequent measurements by the first and second detectors 30, 40 are received by the computer 50.

[0117] Thus, the computer 50 preserves the values of the first and second correction factors when the first and second detectors 30, 40 are operating correctly.

[0118] Furthermore, the computer 50 is further configured to increment a counter recorded in the storage area when the computed integral is outside the predefined reference average value interval. For example, the computer 50 increments the value of the counter recorded in the storage area by 1.

[0119] Moreover, the computer 50 is configured to diagnose a clogging of the first probe 30 when the value of the counter is equal to a predefined counter threshold. More particularly, in the present example, the counter has been incremented.

[0120] The counter threshold is notably predefined, for example by the manufacturer, and its value is also recorded in the memory area of the computer 50. The value of the counter threshold is notably less than 20, preferably less than or equal to 10.

[0121] Moreover, when the computer 50 diagnoses a clogging of the first probe 30, the computer 50 is configured to stop the recording of the values of the first and second correction factors for a predefined descaling time interval.

[0122] Moreover, when the computer 50 diagnoses a clogging of the first probe 30, the computer 50 is also configured to reinitialize the value of the counter, notably to 0, and to trigger a descaling operation of the first probe 30.

[0123] The predefined descaling time interval notably corresponds to the time necessary to descale the first probe 30. For example, the predefined descaling time interval is equal to a value between 10 minutes and 2 hours, preferably as short as possible.

[0124] During the descaling operation, the heat engine 10 is run at high speed, with a high flow rate and temperature of the gases in the heat engine 10. Under these conditions, the soot previously deposited on the first probe 30 and clogging the first probe 30 burns due to the high temperature and is evacuated due to the large flow rate.

[0125] Moreover, during the descaling operation, the computer 50 can also be configured to close the EGR (for “Exhaust Gaz Recirculation” in English) valve of the heat engine 10. The EGR valve notably makes it possible to redirect the exhaust gases emitted by the heat engine 10 towards the injectors of the heat engine 10, so that the exhaust gases are burned a second time. This increases the amount of soot released by the heat engine 10 into the exhaust gases. When the EGR valve is closed, this notably makes it possible to limit the release of soot into the exhaust gases, and thus also the clogging of the first probe 30.

[0126] To do so, the computer 50 is configured to send a control signal to the EGR valve of the heat engine 10, the control signal comprising a run instruction instructing the closing of said EGR valve.

[0127] The control signal can be sent directly to the EGR valve, or via another computer installed in the vehicle 1.

[0128] The computer 50 comprises a processor capable of implementing a set of instructions enabling the implementation of the functions described above.

[0129] Therefore, the computer 50 is able to diagnose blockages in the first detector 30 and, if necessary, trigger descaling of the first detector 30.

[0130] method

[0131] Now refer to Figure 4 To describe an embodiment of the method.

[0132] The method includes a measurement step E1, in which a first parameter P1 and a second parameter P2 are measured within a measurement time interval. In measurement step E1, a first detector 30 measures the value of the first parameter P1, which is related to the oxygen content in the exhaust gas at the outlet of the thermal engine 10. Furthermore, a second detector 40 measures the value of the second parameter P2, which is related to the oxygen content in the exhaust gas at the outlet of the pollution removal system 20.

[0133] The method includes a sending step E2, in which the values ​​measured by the first detector 30 and the second detector 40 are sent to the computer 50. Furthermore, the values ​​measured by the first detector 30 and the second detector 40 are associated with identifiers of the first detector 30 and the second detector 40, respectively.

[0134] The method further includes a receiving step E3, in which computer 50 receives measurement values ​​sent by first detector 30 and measurement values ​​sent by second detector 40. Furthermore, during this step, computer 50 identifies whether the value was sent by first detector 30 or second detector 40 based on identifiers associated with each measurement value of first parameter P1 and second parameter P2, respectively.

[0135] Following the receiving step E3, the method includes a selection step E3', which selects the received values ​​to be considered. During the selection step E3', the computer 50 determines a first time t1 and a second time t2 to define the measurement time interval to be considered, thereby determining which received values ​​to select and consider next.

[0136] After selecting step E3′, the method includes applying step E4, whereby computer 50 applies a first correction factor to each received value measured by first detector 30 within the measurement time interval and applies a second correction factor to each received value measured by second detector 40 within the measurement time interval.

[0137] The method also includes a determination step E5, in which computer 50 determines the changes in the first coefficient and the second coefficient.

[0138] More specifically, during the determining step E5, the computer 50 determines the variation of the first air coefficient over the defined measurement time interval on the basis of the received values measured by the first detector 30 to which the computer 50 has applied the first correction factor and on the basis of the correspondence table. In particular, for each received value of the first parameter P1, the computer 50 selects the corresponding value of the first air coefficient from the correspondence table.

[0139] In addition, the computer 50 determines the variation of the second air coefficient over the defined measurement time interval on the basis of the received values measured by the second detector 40 to which the computer 50 has applied the second correction factor and on the basis of the correspondence table. In particular, for each received value, the computer 50 selects the value of the second air coefficient from the correspondence table.

[0140] The method then comprises a computing step E6 in which the computer 50 computes the integral between the variation of the first coefficient and the variation of the second coefficient over the computation time interval.

[0141] The method then comprises a mean value computing step E7 in which, when the value of the computed integral is comprised within a reference mean value interval, the computer 50 computes the mean value between the value of the computed integral and a predetermined mean value previously recorded in a storage area of the computer 50. The computed new mean value is then recorded in the storage area, as a replacement of the predetermined mean value.

[0142] In addition, if the value of the computed integral is comprised within a predefined reference mean value interval, the method then comprises a decrementing step E8 in which the computer 50 decrements a counter, the value of which is recorded in the storage area.

[0143] In addition, when the computed integral is comprised within a predefined reference mean value interval, the method comprises a recording step E9 in which the first correction factor previously applied to each received measured value of the first parameter P1 and the second correction factor previously applied to each received measured value of the second parameter P2 are recorded. The decrementing step E8 and the recording step E9 can be performed sequentially or simultaneously.

[0144] Conversely, if the computed integral is outside the predefined reference mean value interval, the method comprises an incrementing step E10 in which a counter, the value of which is recorded in the storage area, is incremented.

[0145] When the value of the counter thus incremented is equal to a predefined counter threshold value, the method comprises a diagnosing step E11 in which a clogging of the first detector 30 is diagnosed. In addition, after the diagnosing step E11, the computer 50 reinitializes the value of the counter to 0.

[0146] Furthermore, after the diagnostic step E11 of diagnosing the clogging of the first probe 30, the method comprises a triggering step E12 of triggering a descaling operation of the first probe 30 for a predefined descaling time interval. In particular, in this case, the heat engine 10 is run at high speed so that the gas flow and the temperature in the heat engine 10 are high in order to burn and expel the soot that clogs the first probe 30.

[0147] As another example, during the descaling operation, the computer 50 sends a control signal to the EGR valve in order to stop its operation during the predefined descaling time interval.

[0148] The method according to the application advantageously makes it possible to detect the clogging of the first probe 30 and, if necessary, to trigger a descaling operation of said first probe 30. Since the clogging is sudden, the method makes it possible to quickly detect the clogging of the first probe 30. Furthermore, in the opposite case, i.e. when the first probe is not clogged but is running normally, the method makes it possible to record the values of the first and second correction factors of the first probe 30 corresponding to the normal operation.

Claims

1. Computer (50) for a vehicle (1), the vehicle (1) comprising: - a thermal engine (10), - a pollution abatement system (20) in fluid communication with the thermal engine (10) and configured to abate pollution from exhaust gases of the thermal engine (10), - a first probe (30) disposed between an outlet of the thermal engine (10) and an inlet of the pollution abatement system (20) and configured to measure a first parameter (PI) related to an amount of oxygen in the exhaust gases at the outlet of the thermal engine (10), - a second probe (40) disposed at an outlet of the pollution abatement system (20) and configured to measure a second parameter (P2) related to an amount of oxygen in the exhaust gases at the outlet of the pollution abatement system (20), the computer (50) being configured to communicate with the first probe (30) and the second probe (40), the computer (50) comprising a storage area in which a predetermined counter value is recorded, the computer (50) being configured to: a) receive values measured by the first probe (30) and the second probe (40) in a predefined measurement time interval, b) determine a variation of a first air coefficient in the predefined measurement time interval based on the values received from the first probe (30) and a variation of a second air coefficient in the predefined measurement time interval based on the values received from the second probe (40), the first air coefficient and the second air coefficient being defined as a ratio of two introduced air masses: an introduced air mass in the thermal engine (10) and an introduced air mass corresponding to a theoretical air mass demand for a complete combustion of a predefined fuel quantity injected into the thermal engine (10), c) calculate an integral between the variation of the first air coefficient and the variation of the second air coefficient in a calculation time interval comprised in the predefined measurement time interval, d) determine whether the calculated integral is comprised in a predefined reference average value interval or outside the predefined reference average value interval, e) decrement the counter when the calculated integral is comprised in the predefined reference average value interval, f) increment the counter when the calculated integral is outside the predefined reference average value interval, g) diagnose a clogging of the first probe (30) when the value of the counter is equal to a predefined counter threshold value.

2. Computer (50) according to claim 1, configured to trigger a descaling operation of the first probe (30) when the computer (50) diagnoses a clogging of the first probe (30).

3. Computer (50) according to claim 1, configured to reinitialize the value of the counter when it diagnoses a clogging of the first probe (30).

4. Computer (50) according to any one of claims 1 to 3, configured to apply, before determining the variation of the first air coefficient and the variation of the second air coefficient, a first correction factor to each value received by the computer (50) and measured by the first probe (30) and a second correction factor to each value received by the computer (50) and measured by the second probe (40).

5. The computer (50) according to claim 4, configured to record the applied first correction factor and the applied second correction factor when the computed integral is comprised within a predefined reference average value interval.

6. The computer (50) according to claim 4, further having recorded in a memory area of the computer (50) a predefined correspondence table comprising, for each value of the first parameter (PI), a value of the associated first air coefficient and, for each value of the second parameter (P2), a value of the associated second air coefficient.

7. The computer (50) according to any one of claims 1 to 3, wherein Said first parameter (PI) and second parameter (P2) correspond to a pumping current, which represents the current supplied to the pumping unit when the exhaust gases flow through the pumping unit of the first probe (30) and of the second probe (40), respectively.

8. The computer (50) according to any one of claims 1 to 3, wherein The measurement time interval is defined between a first time instant (tl) and a second time instant (t2), the first time instant (tl) being defined as the time instant at which the fuel injection in the heat engine (10) stops, and the second time instant (t2) being defined as the time instant at which at least one of the first probe (30) and of the second probe (40) measures a value equal to a predefined maximum threshold value.

9. The computer (50) according to any one of claims 1 to 3, wherein The computation time interval is defined between the first time instant (tl) and a third time instant (t3), the first time instant (tl) being defined as the time instant at which the fuel injection in the heat engine (10) stops, and the third time instant (t3) being defined as the time instant at which the value measured by at least one of the second probes (40) starts to be greater than or equal to the value measured by the first probe (30).

10. Vehicle (1) comprising: - a heat engine (10), - a pollution abatement system (20) in fluid communication with the heat engine (10) and configured to abate pollution from exhaust gases originating from said heat engine (10), - a first probe (30) disposed between an outlet of the heat engine (10) and an inlet of the pollution abatement system (20) and configured to measure a first parameter (PI) related to the oxygen content in the exhaust gases at the outlet of the heat engine (10), - a second probe (40) disposed at an outlet of the pollution abatement system (20) and configured to measure a second parameter (P2) related to the oxygen content in the exhaust gases at the outlet of the pollution abatement system (20), - a computer according to any one of claims 1 to 7.

11. Method for diagnosing a clogging of the first probe (30) of a vehicle (1) according to claim 10, comprising the following steps: a) the first probe (30) and the second probe (40) measure (El) the first parameter (PI) and the second parameter (P2) for a predefined measurement time interval, b) determining (E5) a change of a first air coefficient over a predefined measurement time interval based on values received from the first probe (30) and determining (E5) a change of a second air coefficient over the predefined measurement time interval based on values received from the second probe (40), the first air coefficient and the second air coefficient being defined as the ratio of two introduced air masses: an introduced air mass in the heat engine (10) and an introduced air mass corresponding to a theoretical air mass demand for a complete combustion of a predefined fuel quantity injected into the heat engine (10), c) calculating (E6) an integral between the change of the first air coefficient and the change of the second air coefficient over a calculation time interval comprised in the predefined measurement time interval, d) decrementing (E8) a counter when the calculated integral is comprised in a predefined reference average value interval, e) incrementing (E10) the counter when the calculated integral is outside the predefined reference average value interval, f) diagnosing (E11) a clogging of the first probe (30) when the value of the counter is equal to a predefined counter threshold value.

12. Computer program product, characterized in that a computer program comprising a set of program code instructions, the program code instructions, when executed by one or more processors, configure the one or more processors to implement the method according to claim 11.

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