EP2653677A2 - Method and device for determining the quantity of soot particles introduced in a lubricating oil for a diesel engine - Google Patents

Abstract

The method involves calculating a median value of a parameter for a given group according to the parameter statements for each interval of the group. A load in soot particles introduced into a lubrication oil of a diesel engine for the given group is determined according to a pre-established mapping. The loads in soot particles corresponding to the given group are added to the preceding groups to determine a total load of evaluated soot particles during the operation of the corresponding engine. An independent claim is also included for a device for determining quantity of soot particles introduced in lubricating oil for a diesel engine of a car.

Description

The invention relates to a method for evaluating the soot particle charge introduced into a lubricating oil of a diesel engine and a device for carrying out said method.

More generally, this evaluation method can be part of a method of adapting the emptying frequency of a diesel engine according to the evaluation of the soot particle charge introduced into the oil by forming the first part of said adaptation process but it is not mandatory.

It is known that the combustion of diesel in diesel engines generates soot combustion. The quantity of these combustion soot is a function notably of the combustion temperature and the diesel fuel richness (see the Pishinger diagram illustrated in figure 1 of the present patent application).

These soot can be transmitted in the lubricating oil of the engine by the oil film covering the wall of a cylinder of the engine, this during complex processes of thermophoresis and turbulent diffusion, the contaminated oil at the top of the barrel being brought back into the oil tank by scraping the shirt by the segments.

This pollution of the oil must be taken into account by these soot particles, in particular to determine the need for renewal of the lubricating oil and to adapt the emptying interval accordingly. Indeed, an oil so polluted by soot can cause premature wear of the engine components, by abrasion of the lubricated contacts, before reaching the nominal emptying step.

Thus, a lack of knowledge of the degree of pollution of the lubricating oil by soot particles excludes the possibility of adapting the maintenance of the lubricant to the severity of use.

The document FR-A-2,610,724 discloses a device for measuring the concentration of soot in a diesel engine oil. This device includes a soot concentration sensor in the form of a capacitive sensing element immersed in the lubricating oil of the diesel engine.

The concentration sensor described in this document is therefore immersed in oil at high temperature which strongly solicits it, said sensor being able to be damaged by its proximity in a very high temperature environment formed by the oil tank or being able to deliver oil. false measures.

The problem underlying the present invention is to estimate in real time the contamination rate of the lubricating oil of a diesel engine by soot particles from the combustion of diesel, this in a reliable and simple manner and without the help of a sensor.

• décomposition d'une durée de fonctionnement du moteur en groupes, chaque groupe comprenant le même nombre limité d'intervalles de temps successifs,
• pour chaque intervalle d'un groupe donné, acquisition d'au moins un paramètre représentatif des conditions de fonctionnement du moteur,
• calcul d'une valeur moyenne dudit au moins un paramètre pour le groupe donné selon lesdits au moins un paramètre relevés pour chacun des intervalles dudit groupe,
• détermination d'une charge en particules de suie introduite dans l'huile de lubrification du moteur pour le groupe donné selon au moins une cartographie préétablie,
• sommation des charges en particules de suie correspondant au groupe donné et aux groupes le précédant afin de déterminer une charge totale de particules de suie évaluée pendant le fonctionnement du moteur correspondant.

To achieve this objective, there is provided according to the invention a method for evaluating the soot particle charge of the lubricating oil of a diesel engine, said method comprising the following steps:

• decomposing a running time of the motor into groups, each group comprising the same limited number of successive time intervals,
• for each interval of a given group, acquisition of at least one parameter representative of the operating conditions of the engine,
• calculating an average value of said at least one parameter for the given group according to said at least one parameter recorded for each interval of said group,
• determining a soot particle charge introduced into the engine lubricating oil for the given group according to at least one predetermined mapping,
• summation of the soot particles charges corresponding to the given group and groups preceding it to determine a total charge of soot particles evaluated during operation of the corresponding engine.

The technical effect is to obtain an accurate assessment of the soot particle charge introduced into the lubricating oil. Such a method and device operate without the aid of a sensor and thus do not present any risk of false measurement or deterioration.

Advantageously, said at least one parameter is chosen from the engine speed, the engine load and the engine water temperature, these parameters being taken individually or in combination.

Advantageously, said at least one parameter is measured in real time, the duration of an interval being one tenth of a second and the number of intervals of a group being 10.

Advantageously, the mapping or mappings are pre-established either on a test bench, said at least one parameter then being measured while the load in soot particles is determined by taking oil samples from the engine and measuring the soot load that it contains.

• décomposition du kilométrage lors du fonctionnement du moteur en plusieurs intervalles kilométriques successifs,
• pour chaque intervalle kilométrique, acquisition de la masse d'huile de lubrification effective en tenant compte des pertes par (consommation d'huile) de même qu'acquisition de la charge en particules de suie introduite dans ladite huile pour cet intervalle kilométrique,
• sommation de ladite charge en particules de suie pour ledit intervalle kilométrique avec les charges en particules de suie acquises pour les intervalles kilométriques précédents afin d'obtenir une charge totale en particules de suie, ceci en tenant compte de la perte de charge en particules lors de la perte d'huile,
• rapport de la charge totale en particules de suie sur la masse d'huile de lubrification en tenant compte des pertes pendant ledit intervalle kilométrique et les intervalles kilométriques précédents.

Advantageously, the evaluation method comprises the following steps:

• decomposition of the mileage during the operation of the engine in several successive kilometric intervals,
• for each kilometric interval, acquisition of the mass of effective lubricating oil taking into account losses by (oil consumption) as well as acquisition of the soot particulate load introduced into said oil for this kilometric interval,
• summation of said soot particles charge for said kilometric interval with the soot particulate charges acquired for the preceding kilometric intervals in order to obtain a total charge of soot particles, taking into account the particulate pressure drop during oil loss,
• the ratio of the total charge of soot particles to the lubricating oil mass taking into account the losses during the said kilometer interval and the preceding kilometric intervals.

The invention also relates to a device for implementing such a method for evaluating the soot particle charge of the lubricating oil of a diesel engine, said device comprising means for communicating with a fuel cell element. control of the motor as well as means for acquiring in real time at least one parameter representative of the operating conditions of the motor transmitted by said element, means for calculating an average value of said at least one parameter for a given group according to said at least one parameter recorded for each of the intervals of said group, means for storing at least one preset cartography, calculation means for each group of the soot particulate charge introduced into the lubricating oil from said at least one averaged parameter, these calculation means being associated with at least one mapping and means for summing the respective soot particles loads of a group and groups preceding it.

Advantageously, the device is integrated with the motor control.

The invention also relates to a diesel engine, characterized in that its oil consumption is estimated in accordance with such a method or by such a device.

The invention finally relates to a motor vehicle, characterized in that it comprises such a diesel engine.

• la figure 1 représente une courbe de Pischinger montrant la délimitation d'un domaine de formation de suies en fonction de la température locale régnant dans le moteur d'un véhicule Diesel et de l'excès d'air dans un mélange air-gazole alimentant ledit moteur,
• la figure 2 est un schéma des diverses étapes d'un procédé d'évaluation de la charge de particules de suie introduite dans une huile de lubrification d'un moteur Diesel selon la présente invention, ce procédé d'évaluation étant complété par un procédé d'adaptation de la fréquence de vidange d'un moteur Diesel en fonction de l'évaluation de ladite charge de particules de suie introduite, le procédé d'évaluation incluant le procédé d'adaptation pour ses premières étapes.

Other features, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings given by way of non-limiting examples and in which:

• the figure 1 represents a Pischinger curve showing the delimitation of a soot formation domain as a function of the local temperature prevailing in the engine of a diesel vehicle and of the excess air in an air-diesel mixture feeding said engine,
• the figure 2 is a diagram of the various steps of a method for evaluating the soot particle charge introduced into a lubricating oil of a diesel engine according to the present invention, this evaluation method being completed by a method of adaptation of the emptying frequency of a diesel engine as a function of the evaluation of said introduced soot particle charge, the evaluation method including the adaptation method for its first steps.

Referring to the figure 1 , it is recalled that the soot is produced during the combustion of hydrocarbons. The soot particles emitted by a diesel engine are essentially composed of carbon but may contain other elements such as oxygen or hydrogen.

The figure 1 , illustrating a Pischinger curve well known to motorists, shows the delineation of a formation zone S of soot particles according to the engine temperature in degrees Kelvin shown on the ordinate and the excess of local air in the air-diesel mixture shown on the abscissa, this for a diesel engine of a motor vehicle.

For the curve illustrated in figure 1 the formation of soot particles occurs essentially above 1400 ° K for a gas oil-rich air-diesel mixture, the excess of local air then being substantially between 0 and 0.5. This is mainly explained by the presence of an excess of diesel, source of the formation of soot particles.

To the figure 1 , it is also shown that the oxidation O of the soot is at a temperature greater than 1000 ° K for an excess of local air of between 1 and 2. This does not however concern the soot particles introduced into the oil of engine lubrication.

As previously mentioned, some of these soot particles are found in the lubricating oil of the diesel engine and affect the lubricating quality of the oil. This requires to provide a drain of the lubricating oil so polluted by the soot particles with a shorter interval between two oil changes that initially planned and therefore to adapt the frequency of emptying to the soot particle load present in the 'oil.

The present invention therefore proposes to evaluate the load of soot particles in the lubricating oil, taking into account the driving conditions of the motor vehicle. Advantageously, the present invention proposes to use this evaluation in order to carry out or not a draining of the lubricating oil, this emptying taking place when the load of soot particles estimated to be contained in the oil reaches a limit value, this taking into account account of the mass of lubricating oil then present in the engine.

When the load of soot particles does not exceed said limit value, the oil changes are conducted according to the usual cycle of emptying determined for the motor vehicle.

The figure 2 shows a diagram of the various steps of the soot particle charge evaluation method introduced into a lubricating oil of a Diesel engine according to the present invention, this method being advantageously integrated into a method of adapting the emptying frequency of a diesel engine according to the evaluation of said soot charge introduced into the lubricating oil.

From the initial step referenced 0, the first step 1 of the evaluation method provides a statement by communication with a control element of the vehicle, more particularly of the motor control type. This makes it possible to know the mileage Km of the vehicle at a given moment, this mileage being taken as initial mileage after having been transmitted by the control element during the first step 1.

Starting from the value of the initial mileage, the second step 2 of the evaluation method provides for assigning an index i to the mileage recorded, the index i being equal to 1 for the first mileage surveyed. A group of time intervals is thus formed.

The third step 3 of the evaluation method provides for a given time interval a reading by communication with said vehicle control element, in order to know at least one operating parameter of the engine which is likely to influence the production of particles. of soot. The preferred parameters are the R engine speed, the engine load C and the engine water temperature.

These parameters can be taken individually or in combination for the evaluation of the soot particle load that can be found in the lubricating oil. The communication with the vehicle control element, advantageously the engine control, is done in real time.

Such readings are consecutively on each interval i of time, for example every tenth of a second. For an interval i, the mileage records and the said at least one operating parameter C, R are indicated with the index i, the following interval being part of the same group receiving the index i + 1, which takes place in the fourth step of the method referenced 4.

The fifth step of the method provides a comparison of the current index i with a predetermined number of intervals in a group. If i then equals said predetermined value, the readings are transmitted to the next step by the branch O. If i does not reach said value, which corresponds to the branch N, it is again taken to a reading of said at least one operating parameter and thus to the third step 3 of the method, this during a new time interval being the i + 1 of the group and until completion of the group of time interval .

Advantageously, a time interval can be one-tenth of a second and the threshold value for a group of time slots to be complete can be 10 so that an averaged measurement of said at least one operating parameter, as it will be described in the following, corresponds to a second.

The sixth step 6 of the method consists in calculating said at least one operating parameter of the motor by averaging the readings of said at least one parameter for all time intervals forming part of the same group, therefore with a number of intervals. equal to the threshold value. For example, when the threshold value is 10, the average of said at least one operating parameter is made on the readings of ten consecutive time intervals, each record being respectively associated with a time interval.

For example for the motor load C, for a number of intervals of 10, the average motor load Cmoy is defined by Cmoy = average (C1, C2, ....., C9, C10). Again, it should be kept in mind that there may be several engine operating parameters respectively averaged.

The seventh step 7 of the method lies in the prior definition of a method of calculating the soot load estimated to have been introduced into the lubricating oil during the rolling period. Preferably, this quantity is previously estimated by at least one mapping, establishing the soot charge introduced into the oil according to said at least one operating parameter.

As possible maps of the evaluation of the soot load introduced into the oil, it is possible to envisage, for example, a cartography based on the temperature of the engine cooling water, a cartography based on the engine R regime and a cartography based on the motor load C. Mapping based on interpolation between R-speed and C-load maps is also possible and may be preferred. The advantage is to have two maps of carbon introduction in regime / load made at two different water temperatures corresponding to two modes of combustion and to interpolate between them as a function of the water temperature

Alternatively, partial or complete modeling of the introduction of soot particles into the lubricating oil may be carried out. This modeling can be done for example either completely by calculating the production of combustion soot particles, their transfer in the oil film and the scraping in the oil tank or partially by counting the soot load introduced by means of cartographies. soot production in the combustion chamber and then calculating the transfer and scraping. Such calculations have already been undertaken but require substantial means, including three-dimensional calculations incompatible with the power of motor control or CMM. It is therefore advantageous to start directly from the measurement of soot in the oil, which is the direct consequence of all these phenomena.

The one or more maps for evaluating the soot charge introduced into the oil are advantageously coded in the aforementioned vehicle control element and are delivered by said element according to the combustion mode prevailing at the given moment, same as the values of the at least one engine operating parameter.

The eighth step 8 of the method consists in the effective calculation of the soot load estimated to have been introduced into the lubricating oil during a group of time intervals, this with the aid of the detailed cartography or maps at the seventh step. 7.

The ninth step 9 consists in summing the masses of soot by adding to the soot load previously calculated in the eighth step for a given group the soot charge previously summed for the group preceding said given group.

• décomposition d'une durée de fonctionnement du moteur en groupes, chaque groupe comprenant le même nombre limité d'intervalles de temps successifs,
• pour chaque intervalle d'un groupe donné, acquisition d'au moins un paramètre R, C représentatif des conditions de fonctionnement du moteur,
• calcul d'une valeur moyenne dudit au moins un paramètre R, C pour le groupe donné selon lesdits au moins un paramètre R,C relevés pour chacun des intervalles dudit groupe,
• détermination d'une charge en particules de suie introduite dans l'huile de lubrification du moteur pour le groupe donné selon au moins une cartographie préétablie Mc, Cs,
• sommation des charges en particules de suie correspondant au groupe donné et aux groupes le précédant afin de déterminer une charge totale Ms de particules de suie évaluée pendant le fonctionnement du moteur correspondant.

These nine steps relate to a process for evaluating the soot charge but are not all essential. The process according to the invention essentially comprises the following steps:

• decomposing a running time of the motor into groups, each group comprising the same limited number of successive time intervals,
• for each interval of a given group, acquisition of at least one parameter R, C representative of the operating conditions of the engine,
• calculating an average value of said at least one parameter R, C for the given group according to said at least one parameter R, C taken for each of the intervals of said group,
• determining a soot particle charge introduced into the engine lubricating oil for the given group according to at least one pre-established mapping Mc, Cs,
• summation of the soot particles charges corresponding to the given group and groups preceding it to determine a total load Ms of soot particles evaluated during the operation of the corresponding engine.

These nine steps can be followed by the following steps.

The tenth step 10 of the adaptation process provides for the decomposition of the mileage during operation of the engine in several successive kilometric intervals. The number of kilometers traveled after the last oil change is compared to an appropriate mileage threshold value for incrementing the soot load over a sufficient engine operating time.

Advantageously, this threshold value is equal to 1000 km. During this tenth step 10, the mileage is raised by communication with the aforementioned vehicle control element. A comparison of the mileage is made with the initial mileage recorded during the first step 1. If the slice formed by the difference of these two kilometers does not reach the threshold value, then it is returned by the branch N to the third step. 3 of the method for reading at least one operating parameter and the readings continue for each consecutive time interval. In the other case, symbolized by branch 0, the questioning of the merits of a continuous emptying.

The eleventh step 11 provides for the attribution of a second index n for a succession of readings in order to determine whether or not an emptying is to be done, this within a mileage range corresponding to the threshold value defined in FIG. tenth step 10, said mileage being advantageously 1000 kilometers.

The twelfth step 12 provides for the updating of the mass of oil contained in the engine. Indeed, this mass of oil suffers losses during operation of the vehicle, losses by consumption of the oil "CsH" which are estimated in advance in or raised by the control element of the vehicle, preferably the engine control. For each step n, it is proceeded to oil loss estimates estimated Csh, oil percentage ph and kilometers traveled at the previous kilometric interval Km_n-1, this in communication with the engine control element.

Thus, for each kilometer interval, a mass of oil Mh is calculated from an oil consumption communicated by the control element and a mass of soot Ms introduced into the oil, this mass Ms being calculated from of the mass introduced during 1000 km to which one subtracted a mass of soot introduced lost because of the loss in oil.

où p_n est le pourcentage total de suie introduite pour l'intervalle kilométrique n, p_n-1 le pourcentage total de suie introduite pour l'intervalle kilométrique n-1, Mhn-1 la masse d'huile pour l'intervalle n-1, Mhn la masse d'huile pour l'intervalle n, Ms la masse de suie introduite lors de l'intervalle n.The thirteenth step 13 provides for the calculation of a total percentage p_n of soot introduced into the oil at the end of a kilometer interval. This total percentage p_n of soot introduced into the oil is calculated according to the total percentage p_n-1 of introduced soot calculated at the end of the preceding kilometer interval taking into account, firstly, the mass of soot lost due to the loss. oil between these two intervals and, secondly, the soot mass Ms introduced during the kilometer interval n. So : $$\mathrm{p\_n}=\mathrm{p\_n}-1\left(\mathrm{Mhn}-1/\mathrm{Mhn}\right)+100\mathrm{ms}/\mathrm{Mhn}$$

where p_n is the total percentage of soot introduced for the kilometer interval n, p_n-1 the total percentage of soot introduced for the kilometer interval n-1, Mhn-1 the mass of oil for the n-1 interval, Mn the mass of oil for the interval n, Ms the mass of soot introduced during the interval n.

The fourteenth step 14 provides a comparison of the total percentage p_n of soot introduced previously calculated with a drain threshold value representative of a need to drain the lubricating oil.

If said total percentage p_n is greater than the drain threshold value, then a drain is proposed and the process continues with branch O with reset of the main parameters. The need for draining is signaled to the driver by any means.

If the total percentage p_n is lower than the drain threshold value, it is not proposed to perform a drain. By passing through the N-branch after the fourteenth step 14, it is again proceeded to the succession of the preceding steps 2 to 14 starting with the second step 2 and the attribution of the index 1 for a first time interval so to make new readings of at least one engine parameter and the soot load calculations introduced.

It is possible to compare another parameter than the total percentage of soot introduced with a drain threshold value. Thus, at a predetermined threshold value representative of a need for emptying, it is possible to compare a ratio of the total charge of soot particles on the lubricating oil mass, taking into account the losses during said kilometer interval and the kilometric intervals. previous after the last emptying, a new drain being proposed when said ratio is greater than the threshold value of emptying. Step 14 retrieves the information "emptying" and then resets the model taking into account the residual.

où p_n est le pourcentage total de suie introduite pour le pas n juste avant vidange, Mhrés est la masse d'huile résiduelle et Mhnom est la masse d'huile correspondant à la masse totale d'huile ajoutée après vidange additionnée de la masse d'huile résiduelle.The fifteenth step 15 calculates the total residual percentage of soot introduced and contained in the residual oil remaining in the engine after draining. This total percentage is expressed according to the formula: $$\mathrm{near}=\mathrm{p\_n}\mathrm{.}\mathrm{Mhrés}/\mathrm{Mhnom}$$

where p_n is the total percentage of soot introduced for the step n just before emptying, Mhrés is the mass of residual oil and Mhnom is the mass of oil corresponding to the total mass of oil added after draining with added mass of residual oil.

The sixteenth step 16 indicates that the steps 17, 18 and 19 go hand in hand with the fifteenth step 15, in order to update the basic parameters of the evaluation method of a drain, since an emptying has been done.

Thus, in the seventeenth step 17, the odometer used as a basis for determining the mileage intervals of step n is reset to the value of the mileage reached during the emptying. In addition, at the eighteenth step 18, the number n of kilometric intervals of oil mass, soot mass and total percentage of soot input are also reset to zero as well as to the ninth step 19 the total percentage of starting soot p_0 is set to the total residual percentage of soot introduced.

After the update of the mileage, the index number of the survey interval just before the emptying and the total percentage of soot introduced, the process of adapting the emptying frequency of a diesel engine starts again in step 1 and passes by the nine steps of the soot charge evaluation method initiating said adaptation process to complete steps 10 to 19 as previously mentioned.

The invention also relates to a device for implementing a method for evaluating the soot particle charge of the lubricating oil of a diesel engine. The device comprises means for communicating with a motor control element as well as means for real-time acquisition of at least one parameter R, C representative of the operating conditions of the motor transmitted by said element, means for calculating the motor. an average value of said at least one parameter R, C for a given group according to said at least one parameter R, C taken for each of the intervals of said group, means for storing at least one pre-established Mc, Cs mapping, means calculating for each group the soot particulate charge introduced into the lubricating oil from said at least one averaged R, C parameter, said means being associated with at least one Mc, Cs mapping and charge summing means respective soot particles of a group and groups preceding it.

This device can be advantageously integrated in motor control or CMM.

Advantageously, such a device is included in the element for controlling the operation of the motor, more particularly the motor control.

• il n'y a pas de contrainte d'implantation du dispositif comme cela serait le cas pour un capteur et les paramètres de fonctionnement du moteur sont aisément calibrables,
• il est obtenu un gain de charge et de mémoire du contrôle moteur, quand celui-ci héberge le dispositif selon l'invention, par rapport à une modélisation physique du phénomène,
• la calibration du ou des paramètres de fonctionnement est facilitée en étant basée sur des essais existants déjà prévus dans les processus de validation du moteur.

The advantages of the present invention are numerous. We can mention among others:

• there is no constraint of implantation of the device as it would be the case for a sensor and the operating parameters of the engine are easily calibrated,
• it is obtained a charge and memory gain of the motor control, when it hosts the device according to the invention, compared to a physical modeling of the phenomenon,
• the calibration of the operating parameter (s) is facilitated by being based on existing tests already provided for in the engine validation processes.

Claims (9)

A method of evaluating the soot particle charge of the lubricating oil of a diesel engine, said method comprising the steps of: decomposing a running time of the motor into groups, each group comprising the same limited number of successive time intervals, For each interval of a given group, acquisition of at least one parameter (R, C) representative of the operating conditions of the engine, Calculating an average value of said at least one parameter (R, C) for the given group according to said at least one parameter (R, C) recorded for each of the intervals of said group, Determining a soot particle charge introduced into the engine lubricating oil for the given group according to at least one predetermined mapping (Mc, Cs), • summation of the soot particles charges corresponding to the given group and groups preceding it to determine a total charge (Ms) of soot particles evaluated during the operation of the corresponding engine. Evaluation method according to the preceding claim, wherein said at least one parameter (R, C) is chosen from the engine speed (R), the engine load (C) and the engine water temperature, these parameters being taken individually or in combination. Evaluation method according to any one of the two preceding claims, for which the said at least one parameter (R, C) is measured in real time, the duration of an interval being one tenth of a second and the number of intervals of one group being 10. Evaluation method according to the preceding claim, for which the mapping (s) (Mc, Cs) are pre-established either on a test bench, said at least one parameter (R, C) then being measured while the soot particle load is determined by sampling the engine oil and measuring the load in soot that it contains or by modeling the introduction of soot particles into the lubricating oil. A method as claimed in any one of the preceding claims, which also comprises the following steps: • decomposition of the mileage during engine operation in several successive kilometric intervals, • for each kilometric interval, acquisition of the effective lubrication oil mass, taking into account the losses by (oil consumption) as well as the acquisition of the soot particulate charge introduced into said oil for this kilometer interval, • summation of said soot particles charge for said kilometric interval with soot particulate loads acquired for the preceding kilometric intervals in order to obtain a total charge of soot particles, this taking into account the particle pressure drop during oil loss, • ratio of the total soot particle load to the lubricating oil mass taking into account losses during the said kilometer interval and the previous mileage intervals. Device for the implementation of a method for evaluating the soot particle charge of the lubricating oil of a diesel engine according to any one of the preceding claims, said device comprising means of communication with an element for controlling the motor as well as means for acquiring in real time at least one parameter (R, C) representative of the operating conditions of the motor transmitted by said element, means for calculating an average value of said at least one parameter (R, C) for a given group according to said at least one parameter (R, C) recorded for each of the intervals of said group, means for storing at least one predetermined mapping (Mc, Cs), calculation means for each group of the soot particulate charge introduced into the lubricating oil from said at least one parameter (R, C) averaged, these calculation means being associated with at least one mapping (Mc, Cs) and means d e summation of the respective soot particles loads of a group and groups preceding it. Device according to the preceding claim, which is integrated in the motor control. Diesel engine, characterized in that its oil consumption is estimated according to a method according to any one of claims 1 to 5 or by a device according to any one of the two preceding claims. Motor vehicle, characterized in that it comprises a diesel engine according to the preceding claim.

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