Method for controlling a purge gas gasoline concentration sensor and associated engine control unit

Abstract

Method for controlling a purge gas gasoline concentration sensor, the method being implemented by a processor of an engine control unit (2) of an internal combustion engine (1) and comprising the following steps: a. Obtaining a measurement of the purge gas gasoline concentration (S100) by the purge gas gasoline concentration sensor, b. Calculating an error E for determining the measured concentration (S225, S245, S255) from internal operating parameters of the internal combustion engine, c. Comparing the error E for determining the measured concentration with a predetermined threshold (S300), d.If the measured concentration determination error E is greater than the predetermined threshold, the purge gas gasoline concentration measurement is considered invalid and the processor assigns the purge gas gasoline concentration an estimated concentration value from internal engine operating parameters (S420), e. If the measured concentration determination error E is less than the predetermined threshold, the purge gas gasoline concentration measurement is considered valid and the processor assigns the purge gas gasoline concentration to the purge gas gasoline concentration measurement (S520). Abstract figure: Figure 2.

Description

Title of the invention: Method for controlling a purge gas gasoline concentration sensor and associated engine control unit Technical field

[0001] The present disclosure relates to the field of engine control of an internal combustion engine and more particularly to the management of a purge gas in such an engine. Prior art

[0002] In order to avoid releasing vaporized gasoline into the atmosphere, it is known to recover gasoline vapors in an absorber also called a "canister". Since this has a limited absorption capacity, it is also planned to purge it regularly by injecting gasoline vapors contained in it into an air intake duct. This avoids the untimely release of gasoline vapors into the atmosphere. Of course, the gasoline vapors injected into the intake duct are taken into account during fuel injection in order to obtain the desired air / gasoline ratio.

[0003] Different strategies can be used to control the purging of the canister and / or the quantity of gasoline in order to limit the release of polluting gases into the atmosphere. According to a first strategy, the quantity of gasoline vapor present in a conduit between the canister and a purge valve is estimated according to different operating parameters of the internal combustion engine. This method lacks precision so that the efficiency of the purging of the canister is not optimal. Thus, gasoline vapors can still be released unintentionally into the atmosphere when the canister is saturated. According to a second strategy described in document US6568240 B1, a gas concentration sensor is placed on the air intake conduit, between an injector and a butterfly valve, in order to measure the concentration of gasoline present in the air intake conduit after the introduction of the purge gas.It is thus possible to control more precisely the air / fuel ratio of the engine and more particularly the quantity of fuel to be admitted into the engine via the injectors to obtain a given air / fuel ratio. However, the position of the sensor does not allow to know precisely the quantity of fuel vapor at the outlet of the canister, which can have repercussions on the emissions of pollutants at the outlet of the catalytic converter. Summary .

[0004] The present disclosure aims to remedy at least in part the drawbacks of the prior art.

[0005] An aim of the present invention is in particular to propose a more reliable evaluation of the gasoline concentration at the outlet of the canister.

[0006] Another object of the present invention is to enable better control of the emission of pollutants into the environment, even in the event of malfunction of the purge gas gasoline concentration sensor.

[0007] According to a first aspect, a method for controlling a purge gas gasoline concentration sensor is proposed, the method being implemented by a processor of an engine control unit of an internal combustion engine and comprising the following steps: a. Obtaining a measurement of the purge gas gasoline concentration C™ by the purge gas gasoline concentration sensor, b. Calculation of an error E in determining the measured concentration from internal operating parameters of the internal combustion engine, c. Comparison of the error E of determination of the measured concentration with a predetermined threshold, d. If the error E in determining the measured concentration is greater than the predetermined threshold, the measurement of the purge gas gasoline concentration is considered invalid and the processor assigns to the purge gas gasoline concentration an estimated concentration value based on internal engine operating parameters, e. If the error E in determining the measured concentration is less than the predetermined threshold, the measurement of the purge gas gasoline concentration is considered valid and the processor attributes the purge gas gasoline concentration measurement Cp- to the purge gas gasoline concentration

[0008] According to another aspect, there is provided an engine control unit of an internal combustion engine, the engine control unit comprising a processor configured to implement the method of controlling a purge gas gasoline concentration sensor described above.

[0009] According to another aspect, there is provided a computer program comprising instructions for implementing all or part of a method as defined herein when this program is executed by a processor. According to another aspect, there is provided a non-transitory, computer-readable recording medium on which such a program is recorded.

[0010] The features set out in the following paragraphs may, optionally, be implemented, independently of one another or in combination with one another:

[0011] - A concentration measurement validity indicator is emitted based on a result of the comparison between the error E of determination of the measured concentration with the predetermined threshold.

[0012] - The error E of determination of the measured concentration is calculated according to of a ratio between a quantity of air and a quantity of gasoline at the outlet of the internal combustion engine. In this case, the ratio between a quantity of air and a quantity of gasoline at the outlet of the engine may correspond to a value measured by a suitable sensor such as a lambda probe or to a set value when the lambda probe only provides indications of transitions between a rich air / fuel mixture (X < 1) and a lean air / fuel mixture (X > 1) and the richness regulation is activated.

[0013] - The error E of determination of the measured concentration is calculated, when a re richness regulation is activated so as to reach a set value Xc of an air / fuel ratio X at the output of the internal combustion engine, as follows:

[0014] [Math.l] p _ 1-ÀA “ 14.77V

[0015] with A = ; R = 1 + Afb, and ~ Qa Àfb being an error E measured when the richness regulation is activated with the set value Xc, the error E being measured on the basis of a measurement of the air / fuel ratio X by a concentration sensor of an air / fuel mixture at the outlet of the internal combustion engine, Qp corresponding to the flow rate of the air / fuel gas mixture passing through the purge valve, Qa corresponding to the air flow entering the butterfly valve.

[0016] - The error E of determination of the measured concentration is calculated, when a re richness control configured to achieve a set value Xc of an air / fuel ratio X at the output of the internal combustion engine is deactivated, as follows

[0017] [Math.2] ...iv / ?... ~ 14.77V

[0018] With: X = Xmes, R = 1 and T , ~ Qa Xmes corresponding to a measurement of an air / fuel ratio X by a concentration sensor of an air / fuel mixture at the outlet of the internal combustion engine, Qp corresponding to the flow rate of the air / fuel gas mixture passing through the purge valve, and Qa corresponding to the air flow entering the butterfly valve.

[0019] - The error E of determination of the measured concentration corresponds to the difference between the measurement of the gasoline concentration of the purge gas C", and an estimated concentration (Cp) from internal operating parameters of the internal combustion engine.

[0020] - The method further comprises a step of storing the last concentration measured by the purge gas gasoline concentration sensor considered valid.

[0021] - The value of the estimated concentration Cp is determined based on the last concentration considered as valid stored, so that at an instant k+1, we have:

[0022] [Math.3] Cp(k+ï)=Cp(k)+ ^Cp

[0023] being the concentration estimated at the previous instant, Cp(0) being the last concentration measured by the purge gas gasoline concentration sensor considered valid, and A Cp being a variable that is a function of at least one internal operating parameter of the internal combustion engine.

[0024] - The variable A Cp is a function of at least one measurement representative of the temperature temperature of a fuel tank associated with the internal combustion engine or the error E in determining the measured concentration calculated when the richness regulation is activated.

[0025] Thus, the described control method makes it possible to check whether the gasoline concentration value of the gas measured by the purge gas gasoline concentration sensor is valid. When the concentration measurement is considered invalid, an estimated value of the concentration is then used instead of the value measured by the purge gas gasoline concentration sensor. This estimated value makes it possible to continue the canister purging and / or fuel injection strategy with an estimated purge gas gasoline concentration value closer to the actual operating state, which makes it possible to optimize the purge performance and limit the emission of polluting gases. Advantageously, the estimation of the purge gas gasoline concentration can take into account the last value of the concentration measured and considered valid.The estimate is therefore more precise since we start from a starting point corresponding to a situation that actually existed. Brief description of the drawings

[0026] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: Fig.l

[0027] [Fig.l] illustrates a position of a purge gas gasoline concentration sensor according to one embodiment. Fig. 2

[0028] [Fig.2] illustrates a method for controlling a purge gas gasoline concentration sensor according to one embodiment. Description of the embodiments

[0029] [Fig.l] schematically illustrates a system comprising an internal combustion engine 1, an engine control unit 2, an air and fuel supply circuit 3 and an exhaust circuit 4.

[0030] The air and fuel supply circuit 3 comprises an intake duct 5 configured to supply an air / fuel mixture to the engine during an intake phase according to one embodiment. Air from the outside 6 is drawn into the intake duct 5 when a so-called butterfly valve 7 is actuated by the engine control unit 2 and an incoming air flow rate is measured by a flow meter 8. Alternatively, the incoming air flow rate can be calculated from measurements of the pressure and temperature of the incoming air. Furthermore, fuel, for example gasoline from a fuel tank 9 can be injected by means of an injector 10, either into the intake duct 5 as shown here, or directly into a combustion chamber of the engine (not shown here) depending on the type of injection used by the internal combustion engine in question.It will be noted that the system also comprises a vaporized fuel absorber 11, also called a "canister" by those skilled in the art, comprising for example activated carbon and connected to the fuel tank. In a known manner, the canister 11 is configured to store and release vaporized fuel, in particular gasoline. The vaporized fuel released by the canister, hereinafter called purge gas, is injected in a controlled manner by a purge valve 12 into the intake duct before or after the butterfly valve 7 depending on the type of operation of the engine. Usually, the purge gas can be injected into the intake duct 5 downstream of the butterfly valve 7 via a pipe 13 connecting the purge valve 12 to the intake duct 5.The purge gas can be injected, when the engine is supercharged, into the intake duct 5 upstream of a compressor or a turbocharger of a supercharging device 14 located before the butterfly valve 7 by means of a pipe 15 connecting the purge valve 12 to the intake duct 5.

[0031] The exhaust circuit 4 comprises a catalytic converter 16 and an exhaust duct 17 for the burnt air / fuel mixture. The exhaust circuit 4 also comprises at least one concentration sensor 18, also called a “lambda probe” by those skilled in the art, configured to measure an air / fuel ratio at the outlet of the engine 1 before the exhaust gases enter the catalytic converter 16.

[0032] It will be noted that the engine control unit 2 is configured to receive data from different sensors (including in particular those mentioned previously) and to control different actuators such as the butterfly valve 7, the purge valve 12 or the injector 10 according to the values ​​provided by the different sensors. The engine control unit 2 therefore comprises a communication interface with the different sensors and actuators. Furthermore, the engine control unit 2 also comprises at least one processor and a memory capable of storing code instructions making it possible to implement the method described with reference to [Fig.2].

[0033] Furthermore, according to the embodiment described here, the system may comprise at least one purge gas gasoline concentration sensor 19 located between the purge valve 12 and the canister 11. It is thus possible, thanks to the sensor 19, to measure the purge gas gasoline concentration at all times, including when the purge valve 12 is closed. Alternatively, a purge gas gasoline concentration sensor may be placed on the intake duct downstream of the location where the purge gas is injected, for example between the duct 13 and the injector 10. The measurement of the purge gas concentration is however less precise than when the purge gas concentration sensor is located before the injection of the purge gas into the intake duct 5.

[0034] [Fig.2] illustrates a method for controlling a purge gas gasoline concentration sensor according to one embodiment. It is recalled here that this method is implemented by a processor of the engine control unit 2.

[0035] Generally, according to the invention, the method comprises a step S100 of obtaining a measurement of the purge gas concentration Cp and a step of determining an error E in determining the measured concentration S200. This error E can be determined in several ways depending on the type of air / fuel mixture concentration sensor at the engine outlet, i.e. lambda probe, used or the richness regulation status (activated / deactivated) in particular. According to a first variant, the error E in determining the measured concentration can be calculated by subtracting from the measured concentration C1^, an estimated concentration Cp from internal engine operating parameters estimated or received by the engine control unit as described later with reference to steps S220 and S240.According to a second variant, the error E for determining the measured concentration can be estimated directly from the air / fuel ratio measured by the concentration sensor 18 at the engine outlet as described with reference to step S251 for example or from a set air / fuel ratio when the richness regulation is activated as described later with reference to step S250. It will be noted that the second variant also involves internal operating parameters of the . engine as described later.

[0036] During step S300, the processor of the engine control unit checks whether the error E for determining the measured concentration is less than a predetermined threshold Th.

[0037] If the error E for determining the measured concentration is less than the predetermined threshold (E < Th), the processor considers that the concentration value C™ measured by the purge gas gasoline concentration sensor is valid and that the purge gas gasoline concentration value Ce corresponds to the value C™ measured by the sensor. The processor of the engine control unit then assigns the concentration measured by the purge gas gasoline concentration sensor 19 during step S100 to the purge gas gasoline concentration Ce during a step S520. The concentration value C'^ measured by the purge gas gasoline concentration sensor 19 is therefore stored in a memory space corresponding to the purge gas gasoline concentration Ce to be taken into account subsequently by the engine control unit 2 to control the engine.

[0038] On the other hand, if the error E in determining the measured concentration is greater than the predetermined threshold (E > Th), the processor considers that the concentration value C1^ measured by the purge gas gasoline concentration sensor 19 is invalid. The concentration value Ce taken into account by the engine control unit is then a purge gas gasoline concentration value C^esthnée from internal engine operating parameters. The internal parameters may come from measurements made by different sensors and received by the engine control unit. They may also be calculated from the measurements received or other parameters stored in a memory of the engine control unit.The processor can then, during a step S420, either assign to the concentration Ce the concentration Cpestimated during one of the steps S220 or S240 described in more detail later, or calculate an estimate of the concentration when the error E in determining the measured concentration has been evaluated on the basis of an air / fuel ratio obtained during one of the steps S250, S251. In this case, with the richness regulation being activated, the processor can use the error in the richness regulation to estimate the fuel concentration of the purge gas as described in more detail later.

[0039] Optionally, a validity indicator Ival of the measurement can also be stored. The value of this indicator depends on the result of the verification made during step S300. For example, a value of 1 can be assigned to the validity indication 1 val, when the error E in determining the measured concentration is less than the predetermined threshold (E < Th) during a step S510 and a value of 0 when the error E in determining the measured concentration is greater than the predetermined threshold (E > Th) during a step S410. The validity indicator Ival also makes it possible to know whether the stored gasoline concentration value Ce corresponds to an estimated value or to a measured value. It will be noted that the best measurement accuracy is of course obtained for a validated measurement. Thus, advantageously, as described later, a concentration measurement considered to be valid can be used to estimate a purge gas concentration more precisely.

[0040] Furthermore, the value of the validity indicator Ival makes it possible to issue a diagnosis of the operation of the sensor. It can in fact be concluded from an invalid measurement that a sensor is defective because it is either poorly calibrated or dirty or one of its components is potentially out of service or damaged.

[0041] The method for controlling a purge gas gasoline concentration sensor is now described in more detail, according to a particular embodiment. In this embodiment, the purge gas gasoline concentration sensor 19 is placed between the canister 11 and the purge valve 12 as illustrated in [Fig. 1]. It will be noted that the purge gas gasoline concentration sensor 19 can also be integrated into the purge valve 12, that is to say in the same housing or be located on the pipe 15 connecting the purge valve 12 to the intake duct when the engine comprises a supercharging device 14.

[0042] In the embodiment described here, step S100 therefore comprises the measurement, by the purge gas gasoline concentration sensor 19, of the purge gas concentration on command from the engine control unit 2 and the storage of the measured value in a memory of the engine control unit 2. It will be noted that during step S100, several successive values ​​can be measured and that only a representative value, for example resulting from first-order filtering or the calculation of a sliding average, can be stored. In other embodiments, the purge gas gasoline concentration can be measured and stored periodically and one of the stored values, for example the last one, can be read on command from the processor during the implementation of step S100.

[0043] During step S200, as mentioned previously, the error E for determining the measured concentration can be determined in different ways depending on the type of air / fuel mixture concentration sensor 18 used and the richness regulation status (activated / deactivated) in particular.

[0044] Step S200 includes a step S210 for checking the state of the purge valve. Thus, in the embodiment described here, the gasoline concentration of the purge gas is measured both when the purge valve is open (indicator VP = 1) and when the purge valve is closed (indicator VP = 0).

[0045] When the purge valve is closed (VP = 0), the purge gas concentration is first estimated during a step S220 then the error E of determining the measured concentration is determined in a step S225 by calculating the difference between the measured concentration C™ obtained in step S100 and the estimated concentration Cp in step S220 according to the following formula:

[0046] [Math.4] E = Cp-Cp

[0047] When the purge valve is open (VP = 1), it is checked, during a step S230, whether the richness regulation is activated by checking for example the value of a corresponding indicator, here RR. If the richness regulation is activated (RR = 1), it is possible to obtain, during a step S250, the setpoint value of the richness regulation. This value is stored in a memory of the engine control unit and can be read by the processor. It can be either the setpoint richness or the setpoint lambda Xc, it being understood that the richness value is the inverse of the lambda value as known to those skilled in the art. It is possible for example, during a step S255, to calculate the error E for determining the measured concentration using the following formula:

[0048] [Math.5] p _ t-ÀR ~ 14.777

[0049] with 2 = ; R = 1 + and T _ ~ Qa Àfh is the error measured during the richness regulation and therefore corresponds to the difference between the richness regulation setpoint Xc and the variable measured by the concentration sensor 18 at the engine output, ^corresponds to the flow rate of the air / fuel gas mixture passing through the purge valve, and <2fl corresponds to the air flow entering the butterfly valve 7 as described previously. Note that Qp and Qa are internal operating parameters of the engine.

[0050] In an alternative embodiment, 2 = 2^ could be used, when the air / fuel mixture concentration sensor 18, i.e. the lambda probe, makes it possible to measure a value representative of an air / fuel ratio.

[0051] In a manner known to those skilled in the art, variable 2 is defined by:

[0052] [Math.6] 2=-<-A 14.7 Q

[0053] With (J the air flow actually pumped by the engine, and Q the flow of gasoline injected into the engine.

[0054] By developing in the formula [Math.6] the terms Q1 and with the following equations:

[0055] [Math.7]

[0056] [Math.8] Q = Q +o" ^ess ^inj

[0057] with Qinj the mass flow rate of gasoline injected by the injectors, and pC mass flow of gasoline from the canister purge injected through line 13 or line 15, Q and Qp correspond to the flow rates previously described with reference to the formula [Math.5], and C'p is the actual concentration of gasoline vapor from the purge.

[0058] Using the following formula:

[0059] [Math.9] / i_ / 1. —I ~'J Cf ^inj “ \ 100 / 14.7 "

[0060] With the lambda error of the richness regulation expressed in percentages, 0e the estimated air flow pumped by the engine, and Q?The estimated fuel flow from the canister purge.

[0061] We thus obtain:

[0062] [Math. 10] A = 4+(1-4)*4

[0063] By introducing f = C, - C,, and taking into account that the actual or estimated purge gas concentration CP is written as the ratio / q, after various simpli factions and changes of variables, we obtain:

[0064] [Math. 11] 1+(1-4)7-441+(1-^ ~ 14.7 47

[0065] Taking into account that T « 1, C^ and Cp« 1, we obtain:

[0066] [Math. 12] - 14,774

[0067] It will be noted that the formula [Math.7] described here corresponds to the case where the purge gas is injected upstream of the butterfly valve 7 via the pipe 13 but that the formula [Math. 12] remains valid when the purge gas is injected into the intake duct via the pipe 15, depending on the type of engine and the operating mode of the engine. (supercharging activated or not).

[0068] Returning to step S230, when the richness regulation is not activated, it is checked, during a step S235, whether the air / fuel mixture concentration sensor 18, i.e. the lambda probe, is a sensor configured to measure a value representative of an air / fuel ratio.

[0069] If the air / fuel mixture concentration sensor 18 is configured to measure a value representative of an air / fuel ratio, a value of the air / fuel ratio measured by the sensor is obtained during a step S251, for example the lambda value Xmes measured by the lambda probe, and the error E in determining the measured concentration is determined during step S255 using the formula [Math.5]. depending on the value of the air / fuel ratio measured by sensor 18, here depending of the lambda value Xmes measured by the lambda probe as described with reference to step S255 with A — R = 1 and T _ Gp . Note that also a 1 ~ Q internal engine operating parameter.

[0070] If the air / fuel mixture concentration sensor 18 is not configured to measure a value representative of an air / fuel ratio, the air / fuel mixture concentration sensor 18 is then configured to detect only transitions between a rich air / fuel mixture (X < 1) and a lean air / fuel mixture (X > 1). In this case, a concentration value is estimated during a step S240 from internal operating parameters of the engine and the error E for determining the measured concentration is determined, during a step S245, by subtracting the gasoline vapor concentration estimated during the step S240 from the measured gasoline vapor concentration obtained during the step S100. according to the formula [Math.4] described previously with reference to step S225.

[0071] Advantageously, the estimation of the gasoline concentration of the purge gas Cj, carried out during steps S220 and S240, can take into account the last gasoline concentration of the purge gas considered to be valid stored during step S520. In this case, an initialization step S000 is implemented during which a gasoline concentration of the purge gas is measured at least once with the activated control loop considered to be valid.

[0072] The estimation of the concentration Cp can, according to one embodiment, take into account the temperature T of the air admitted into the intake duct, which therefore corresponds to the temperature to which the fuel tank is subjected. During steps S220 and S240, the calculation of the estimation of the concentration Cp can be done for example using the following formula:

[0073] [Math. 13] CJ,(Æ+1) =Cep{k) + AC^r)

[0074] With AC; / T) a variable which depends on the temperature T of the air admitted into the intake duct and therefore on the temperature to which the tank 9 is subjected, and C^(0) the last measured value considered as valid of the gasoline concentration of the purge gas either during the initialization step, or during step S520 after the initialization step has been implemented.

[0075] It will be noted that the variable CP(T ) is not defined in the same way depending on whether step S220 or step S240 is executed. Indeed, the variation in the quantity of vaporized gasoline contained in the purge gas does not change in the same way depending on the opening state of the purge valve.

[0076] Then, it is checked in step S300 whether the measurement of the gasoline concentration of the purge gas is valid as described previously, and the concentration evaluated by the processor and subsequently used by the latter to control the engine and the opening of the purge valve is assigned either the measured concentration value (step S520) or an estimated concentration value (step S420).

[0077] It is recalled here that, during step S420, the evaluated concentration Ce is assigned either the concentration CpCstiméc during one of steps S220 or S240, or an estimate of the calculated concentration taking into account the regulation error, for example when the richness regulation is activated.

[0078] The richness concentration can be estimated in a similar manner to what was described previously by incrementing the concentration value estimated at the previous instant in the following manner:

[0079] [Math. 14] c;(k + 1 ) = Cp(k) + AC^E)

[0080] With AC^E") a variable which depends on the error E of determination of the measured concentration determined during the previous step S255, and C^(0) the last measured value considered as valid of the gasoline concentration of the purge gas either during the initialization step, or during step S520 after the initialization step has been implemented.

[0081] It will be noted that the sign of the variable AC^(E) also depends on the sign of the regulation error, for example X / &. Thus, when the mixture is richer than desired (¼ < 0), the sign of the variable AC^E) is positive so that the estimated concentration C / j is incremented and when the mixture is less rich than desired (¼ > 0), the sign of the variable AC^E) is negative so that the estimated concentration C^ is decremented. Indeed, when Xa, < 0, this means that the quantity of gasoline injected should be decreased because the air / fuel mixture is too rich, the concentration Cf, (A) is therefore underestimated, it must therefore be increased. Furthermore, when Xn, > 0, this means that the quantity of gasoline injected should be increased because the air / fuel mixture is lean, the concentration Cf( &) is therefore overestimated and it must be decreased.

[0082] It will also be noted that the value of the variable ACj / Ti) can also depend on the number of openings and the duration of opening of the purge valve 12.

[0083] The method described above is implemented by a processor of the engine controller 2 when the latter wishes to know the concentration of the purge gas in gasoline. The method described above can for example be implemented after the engine start-up phase, after the richness regulation has been activated for the first time. Indeed, in this regime, a purge can be envisaged since the catalyst is capable of treating the residual gasoline in the exhaust gases. This avoids any potential pollution which would be due to a release of unburned gasoline into the atmosphere. The method described above can also be implemented, in certain cases, during an engine restart initiated by a start and stop device.

[0084] Advantageously, according to the method of the invention, the concentration measurement carried out by the purge gas gasoline concentration sensor is validated when the calculated error E is less than a predetermined threshold. This may be a single threshold, for example 5% or two different thresholds, depending on the status of the richness regulation regime (activated / inactivated). Indeed, when the richness regulation is inactivated, the calculated error E is less reliable and a higher threshold may be taken into account to validate or invalidate the concentration measurement made by the purge gas gasoline concentration sensor 19.

Claims

Claims

1. Method for controlling a purge gas gasoline concentration sensor, the method being implemented by a processor of an engine control unit (2) of an internal combustion engine (1) and comprising the following steps: has. b. Obtaining a measurement of the purge gas gasoline concentration C™ (S 100) by the purge gas gasoline concentration sensor, Calculating an error E in determining the concentration measured (S225, S245, S255) from internal operating parameters of the internal combustion engine, the error E of determining the measured concentration is calculated in function of a ratio between a quantity of air and a quantity of gasoline coming out of the internal combustion engine (20 Anies ii. when a richness regulation is activated so as to reach a set value Xc of an air / fuel ratio X at the output of the internal combustion engine, as follows: E = —, with A = Ac ; R — 1 + A fh, and y- _ A fy being an error E measured when the richness regulation is activated with the set value Xc, the error E being measured on the basis of a measurement (Ames) of the air / fuel ratio X by a concentration sensor of an air / fuel mixture (18) at the outlet of the internal combustion engine, Qp corresponding to the flow rate of the air / fuel gas mixture passing through the purge valve (12), and Qa corresponding to the flow rate of air entering the butterfly valve (7), when a richness regulation configured to reach a set value Xc of an air / fuel ratio X at the outlet of the internal combustion engine is disabled, as follows: E = ' ' 14,777. with: A — Ames, R = 1 and T, Xmes cor corresponding to a measurement of an air / fuel ratio X by a concentration sensor of an air / fuel mixture (18) at the outlet of the internal combustion engine, Qp corresponding to the flow rate of the air / fuel gas mixture passing through the purge valve (12), and Qa corresponding to the flow rate of air entering the butterfly valve (7), c. Comparison of the error E of determination of the measured concentration with a predetermined threshold (S300), d. If the error E in determining the measured concentration is greater than the predetermined threshold, the measurement of the purge gas gasoline concentration is considered invalid and the processor assigns to the purge gas gasoline concentration an estimated concentration value based on internal engine operating parameters (S420), e. If the measured concentration determination error E is less than the predetermined threshold, the purge gas gasoline concentration measurement is considered valid and the processor assigns the purge gas gasoline concentration measurement Cp (S520) to the purge gas gasoline concentration.

2. Method for controlling a purge gas gasoline concentration sensor according to the preceding claim, in which a validity indicator (Ivai) of the concentration measurement is emitted as a function of a result of the comparison between the error E of determining the measured concentration with the predetermined threshold (S410, S510).

3. Method for controlling a purge gas concentration sensor according to one of claims 1 to 2, in which the error E in determining the measured concentration corresponds to the difference between the measurement of the gasoline concentration of the purge gas Cp and an estimated concentration Cp from internal operating parameters of the internal combustion engine.

4. Method for controlling a purge gas gasoline concentration sensor according to any one of the preceding claims, in which: - the method further comprises a step of storing the last concentration measured by the purge gas gasoline concentration sensor purge gas considered valid, - the value of the estimated concentration is determined based on the last concentration considered valid stored, so that at a time k+1, we have: [Math. 15] Cp(k+l) + ACp being the concentration estimated at the previous time, C^(0) being the last concentration measured by the purge gas gasoline concentration sensor considered valid and AC'p being a variable that is a function of at least one internal operating parameter of the internal combustion engine.

5. Method for controlling a purge gas gasoline concentration sensor according to the preceding claim, in which the variable A Cp is a function of at least one measurement representative of the temperature of a gasoline tank associated with the internal combustion engine or of the error E in determining the measured concentration calculated when the richness regulation is activated.

6. Engine control unit (2) of an internal combustion engine (1), the engine control unit (2) comprising a processor configured to implement the method of controlling a purge gas gasoline concentration sensor according to any one of the preceding claims.

7. Computer program comprising instructions for implementing the method for controlling a purge gas gasoline concentration sensor according to one of claims 1 to 5 when this program is executed by a processor.

8. Non-transitory recording medium readable by a computer on which is recorded a program for implementing the method of controlling a purge gas gasoline concentration sensor according to one of claims 1 to 5 when this program is executed by a processor.

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