EP1956203B1 - Device and method for estimating the oil consumption of a vehicle engine - Google Patents

Abstract

The device has measurement sensors (2-5) to determine values of engine functioning rate, engine load, and temperatures of cooling water and oil. A calculation unit (1) co-operates with the sensors. The calculation unit has an algorithm to calculate an oil consumption term based on the values of the engine functioning rate and load during a given functioning time. The algorithm permits to calculate another oil consumption term to be applied to the former term from the values of the temperatures for deducing an estimation of intended oil consumption.

Description

The present invention relates to a device and a method for estimating the oil consumption of a vehicle engine.

It also relates to a device and a method for estimating the oil consumption of a vehicle engine adapted to also perform the determination of the amount of oil present in the engine, the diagnosis of this consumption and the prediction of the engine oil. emptying interval.

It applies to all types of internal combustion engines, such as, for example, of the turbocharged diesel type, comprising a pressurized lubricant circuit.

It is known for the purpose of ensuring a durable and efficient operation of an internal combustion engine, to use lubricating oil to reduce the friction of the various moving parts of this engine, such as pistons, shafts cams, crankshaft, etc., and limit the increase in temperature thereof.

It is also known that during its operation, a motor thus lubricated loses oil in particular by combustion of the oil entering the combustion chambers by recirculation of the crankcase gases or through the operating clearances between the segmentation of the pistons and the cylinders. Note that in certain circumstances, this loss of oil can reduce the volume of lubricating oil present in the engine until it reaches and drops the minimum allowable volume of oil in the engine, resulting in severe malfunctions. of the motor.

It is also known that during the operation of an internal combustion engine, unburned fuel in the combustion chambers can flow along the cylinders and pistons and mix with the lubricating oil whose volume and composition find then modified. Note that under certain circumstances, this dilution of the fuel in the oil can increase the volume of lubricating oil to increase and exceed the maximum allowed volume also resulting in severe malfunctions of the engine.

It is also known that lubricating oil loses its properties and essential qualities during operation of the engine, in particular by shearing during its function of reducing the friction of the various moving parts, by oxidation of hydrocarbons by oxidizing substances. present especially in the unburned gases which infiltrate into the housing containing the lubricant, or by dilution of the lubricant with fuel that can pass into the lubricant.

The manufacturers have therefore planned to operate at specified intervals of time or course, for example every 30,000 kilometers, oil changes intended in particular to eliminate the oil whose properties have deteriorated and to return an appropriate amount of oil new. This periodicity recommended to operate the emptying of an engine, on the basis of a given type of oil and for predetermined use cases of the engine, may however be inappropriate in certain situations of use of the vehicle.

Indeed, these phenomena of aging, loss of oil or dilution of fuel can vary in fairly large proportions according to multiple factors including the points of operation of the engine or the type of oil used. It is therefore important to regularly monitor the amount of oil in the engine to ensure that there is always an adequate amount of oil in the engine.

Various devices for controlling the amount of oil present in an engine, are currently used to avoid a too low or too high level of this oil in the engine that can lead to a degradation of the parts of this engine, or even to the breakage of this last.

These devices are either of the mechanical type comprising a gauge allowing a visual reading of the oil level in the crankcase and the indication of a minimum level and a maximum level, either of the electronic type with level sensors. oil and visual display means in the vehicle of the oil level provided by the sensors and, if necessary, warning means, for example of the light or sound type in case of lack of lubricating oil.

The disadvantage of the oil level control gauge is that the driver of the vehicle must manually perform the verification of this oil level, operation that the driver performs less and less including forgetting or negligence.

This disadvantage is eliminated by the electronic oil level control devices for viewing the vehicle dashboard the volume of oil remaining in the engine crankcase of the vehicle. However, the electronic sensors used in these devices fail to provide a measurement accuracy dependent on their cost, thus leading to installing in vehicles, inexpensive sensors but at the same time not very accurate and unreliable, reliable and accurate sensors but extremely expensive.

A certain number of solutions have been developed to dispense with specific sensors for measuring the quantity of oil remaining in an engine and to estimate it directly from the engine operating parameters by using the electronic computers which control the engines and the information that they exploit to operate this control. Thus, the document JP-A2-10266823 describes a device for managing an internal combustion engine that makes it possible to avoid a lack of engine oil by integrating the operating speed of the engine to determine an integrated value of this engine, substituting this value for a correlation expression prescribed for determining an estimated value of oil loss and producing an alarm when the amount of residual oil is less than a prescribed amount.

However, the estimation solutions known to date have the disadvantage of being relatively inaccurate on the estimated value of oil loss and fuel dilution especially due to the parameter (s) of engine operation considered and selected models.

Moreover, the known solutions do not make it possible to deduce from their calculations the residual quantity of oil in the engine, to make a diagnosis of the oil consumption, or to estimate the next emptying interval in particular according to the nature of the oil present in the engine.

The present invention aims to overcome the disadvantages of the known devices for controlling oil level in an internal combustion engine of a motor vehicle.

For this purpose, according to the invention, the device for estimating the oil consumption of a vehicle engine comprises a calculation unit co-operating with means for determining the values taken by predetermined parameters of operation of the engine comprising the operating speed of the engine, the engine load, the engine cooling water temperature and the engine oil temperature, such determining means being such as measuring sensors or the on-board computer of the vehicle.

In the present text, the resultant oil consumption will be called between the loss phenomena, in particular by combustion and the inflow phenomena, in particular by fuel dilution.

According to the invention, this device for estimating the oil consumption is characterized in that the calculation unit comprises an algorithm making it possible to calculate for a given operating period, a first term of consumption of engine oil in based on the values of the operating speed and the engine load during this period and to calculate, from the water and oil temperature values, a second term of engine oil consumption to be applied to the first term for deduce the estimate of the desired oil consumption.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, the calculation unit comprises a memory containing a map of the engine oil consumption as a function of engine speed and load. and the algorithm of this unit can calculate the first engine oil consumption term by linear interpolation of the data contained in the mapping in memory.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, the calculation unit comprises a memory containing a map of the engine oil consumption as a function of engine speed and load. for different engine water temperatures and a memory containing a map of the engine oil consumption as a function of the engine speed and load for different engine oil temperatures and the calculation unit algorithm calculates the second term of engine oil consumption by linear interpolation of the data contained in the stored maps.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, the algorithm of the calculation unit also makes it possible to subtract from a given quantity of oil the estimated oil consumption to determine the amount of oil remaining in the engine.

According to an alternative embodiment of the invention, the device for estimating the oil consumption that is the subject of the invention, the computing unit also cooperates with means for measuring the oil level in the engine providing a measurement of the volume of oil remaining in this engine, and in that the algorithm of the calculation unit makes it possible to compare the remaining volume of oil calculated with the volume of oil remaining measured and to provide information relating to a consumption abnormal oil in case of discrepancy between the remaining oil volumes calculated and measured higher than a predetermined value.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, the means for measuring the oil level are sensors of the electronic type which measure oil levels in stages whose number depends on the number of sensors used.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, the algorithm of the calculation unit making it possible to calculate the remaining quantity of oil is adapted according to the type of oil used in the engine and allows to control means of alerting the driver of the vehicle to perform an oil change when the amount of oil remaining in the engine and calculated according to the type of oil used reaches a critical value.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, the calculation unit comprises a memory containing linear relationship curves, at various constant operating speeds of the engine, between the viscosity of the oil and oil pressure of the engine oil pump and the algorithm is able to determine the type of oil used in the engine from the measurement of the viscosity of the oil obtained according to the pressure of the oil pump according to the operating speed of the engine.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, it comprises on-vehicle sensors making it possible to carry out mass spectrometry to determine the chemical constitution of the oil and the algorithm is suitable. to deduce the type of oil used in the engine compared to a base of data from a memory of the computing unit and relating to various chemical constitutions of different oils.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, it comprises sensors and models from which the algorithm is able to measure periodically the evolution of aging of the properties of the oil. and weighting this measurement by a coefficient which is a function of the remaining amount of calculated oil.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, it comprises means for displaying at least one of the following information: the calculated quantity of oil remaining in the engine and possibly, the amount of oil measured, the information relating to an abnormal oil consumption of the engine, an alert to perform a drain, the remaining mileage of the vehicle to perform the oil change.

According to another characteristic of the device for estimating the oil consumption which is the subject of the invention, this device is integrated in the on-board computer of the vehicle.

The invention also relates to a method for estimating the oil consumption of a vehicle engine consisting in continuously measuring engine operating parameters such as the operating speed of the engine, the engine load, the temperature of the engine, and the engine temperature. of the engine cooling water and the engine oil temperature, which is characterized in that it consists in continuously calculating a first instant engine oil consumption term as a function of the operating speed and the engine oil temperature. load of this engine and calculate, from the measured water and oil temperatures of the engine at these operating speed and engine load, a second term of engine oil consumption to be applied to the first term to correct this last and produce the estimate of the instantaneous oil consumption of the engine.

The method also consists in continuously calculating the sum of the instantaneous oil consumption of the engine and deducting this sum of the quantity of oil initially present in the engine to deduce the amount of residual oil present in the engine.

According to the invention, it is also possible to diagnose the oil consumption of a vehicle engine according to the method of determining, from a continuous calculation of instantaneous oil consumption as a function of operating parameters of the engine. engine speed, engine load, engine cooling water temperature and engine oil temperature, a volume of oil remaining in the engine, measured continuously, from of sensors for measuring the oil level in the engine, a volume of oil remaining in this engine, compare the remaining oil volume calculated with the volume of oil remaining measured, and provide information relating to oil consumption abnormal in the case of deviation between the remaining oil volumes calculated and measured greater than a predetermined value.

According to the invention, it is also possible to predict the emptying interval of the lubricating oil of a vehicle internal combustion engine and which is characterized in that it consists in estimating by calculation in real time the consumption of engine oil from measured parameters of engine operation, such as the operating speed of the engine, the engine load, the engine coolant temperature and the engine oil temperature, determine by calculation the remaining amount of oil from the estimated oil consumption, adjust calculating the engine oil consumption according to the type of oil used in the engine, and informing the driver of the vehicle to perform an oil change when the amount of oil remaining in the engine and calculated in depending on the type of oil used reaches a critical value.

According to one embodiment, the method of predicting the emptying interval consists of determining the type of oil used in the engine from the measurement of the viscosity of the oil.

In another embodiment, the method of predicting the emptying interval is to determine the type of oil used in the engine from the chemical constitution of the oil.

Advantageously, the method for predicting the emptying interval further comprises periodically measuring the aging evolution of the properties of the oil and weighting this measurement by a coefficient which is a function of the remaining amount of calculated oil, and informing the driver of the vehicle to carry out an oil change when the weighted measurement reaches a critical value, or to inform him that his emptying interval decreases or increases to allow him to predict his passage in concession.

The method of predicting the emptying interval is to display on the dashboard of the vehicle the remaining mileage of the vehicle before performing the oil change.

• les figures 1a, 1b et 1c sont des schéma-blocs du dispositif d'estimation de la consommation d'huile d'un moteur à combustion interne de véhicule conforme à l'invention selon trois modes de réalisation de réalisation de l'invention ;
• la figure 2 représente une cartographie permettant de déterminer une consommation d'huile instantanée du moteur en fonction du régime de fonctionnement et de la charge de celui-ci ;
• la figure 3 représente une cartographie permettant de déterminer une valeur de correction de la consommation d'huile instantanée du moteur en fonction de la charge et du régime de fonctionnement de celui-ci pour différentes valeurs de température d'eau de refroidissement de ce moteur ;
• la figure 4 représente une cartographie permettant de déterminer une correction de la consommation d'huile instantanée du moteur en fonction du régime de fonctionnement et de la charge de celui-ci pour différentes valeurs de température d'huile du moteur ;
• la figure 5 est un tableau représentant des valeurs de consommation d'huile instantanée du moteur en fonction du régime de fonctionnement, de la charge, de la température d'eau de refroidissement et de la température d'huile du moteur ;
• la figure 6 est un graphe représentant la relation entre la pression d'huile d'une pompe à huile du véhicule et la viscosité de l'huile à diverses vitesses de rotation constantes du moteur ; et
• la figure 7 représente sous forme de schéma-blocs un dispositif permettant d'estimer le vieillissement des propriétés de l'huile de lubrification d'un moteur.

The invention will be better understood, and other objects, features, details and advantages thereof will appear more clearly in the following explanatory description made with reference to the accompanying schematic drawings given solely by way of example illustrating different embodiments of the invention and in which:

• the figures 1a , 1b and 1 C are block diagrams of the device for estimating the oil consumption of a vehicle internal combustion engine according to the invention according to three embodiments of embodiment of the invention;
• the figure 2 represents a map making it possible to determine an instantaneous oil consumption of the engine as a function of the operating regime and of the load thereof;
• the figure 3 represents a map for determining a correction value of the instantaneous oil consumption of the engine as a function of the load and the operating speed thereof for different values of the cooling water temperature of this engine;
• the figure 4 represents a map for determining a correction of the instantaneous oil consumption of the engine as a function of the operating speed and the load thereof for different engine oil temperature values;
• the figure 5 is a table showing instantaneous oil consumption values of the engine as a function of operating speed, load, cooling water temperature and engine oil temperature;
• the figure 6 is a graph showing the relationship between the oil pressure of a vehicle oil pump and the viscosity of the oil at various constant engine speeds; and
• the figure 7 represents in the form of a block diagram a device for estimating the aging of the properties of the lubricating oil of an engine.

The device of the invention for estimating the oil consumption of an internal combustion engine of a vehicle comprising a pressurized lubricant circuit, such as for example a diesel engine, comprises, as shown in FIG. figure 1a , a calculation unit 1 receiving electrical information signals from sensors for measuring engine operating parameters, in particular a sensor 2 of the operating speed or rotation speed of the engine, a load sensor 3 or a load torque of engine, a sensor 4 for measuring the engine cooling water temperature and a sensor 5 for measuring the oil temperature of this engine.

More specifically, the calculation unit 1 comprises a calculation means 6 receiving the output signals of the sensors 2 to 5 and making it possible to calculate continuously (in real time), during the operation of the engine, and under the control of a algorithm, a first term of CsH instantaneous oil consumption expressed in grams per hour (g / h) of the engine as a function of the values of the engine operating speed and the engine load measured by the two sensors 2, 3.

For this purpose, the calculation unit 1 further comprises a first memory 7 connected to the calculation means 6 and which contains a map of the kind represented in FIG. figure 2 and relating to the engine oil consumption as a function of the operating speed and the load of this engine.

Thus, the calculation means 6 allows a calculation of a first term of the instantaneous oil consumption of the engine for example by linear interpolation of the data contained in the stored map of the figure 2 according to the values of the operating speed of the motor and the load of the latter in the elementary interval of time considered.

The calculation unit 1 further comprises a second memory 8 connected to the calculation means 6 and a third memory 9 also connected to this calculation means.

The memory 8 contains a map of the kind represented in figure 3 the engine oil consumption as a function of the operating speed and the engine load for different engine water temperature values ranging from about 80 ° C to about 110 ° C.

The figure 3 shows that this map consists of layers, one of the plies being relative to the variation of engine oil consumption as a function of the operating speed and the load of this engine at a water temperature of, for example, 80 ° C while the other layer relates to a variation of engine oil consumption depending on the operating speed and the load thereof at a water temperature of for example 100 ° C.

The algorithm of the calculation means 6 makes it possible to calculate a corrective term of oil consumption to be applied to the first term, this corrective term being obtained for example by linear interpolation of the data contained in the map layers of the figure 3 . Thus, with each variation of the engine cooling water temperature, measured by the sensor 4, is assigned a corresponding change in oil consumption and the correction coefficient to be applied to the value of the first term of instantaneous oil consumption. calculated by means 6 from the mapping of the figure 2 is determined by linear interpolation of the oil consumption values assigned to the measured water temperatures.

Similarly, mapping the figure 4 stored in the memory 9 of the calculation unit 1 consists of plies relating to a lubricating oil temperature of the engine which can vary between 100 ° C and about 120 ° C. The algorithm of the calculation means 6 makes it possible to determine, as a function of the operating speed and the engine load and for each oil temperature measured by the sensor 5, an oil consumption value and makes it possible to calculate, for example by linear interpolation, a corrective term for correction of lubricating oil consumption during changes in the oil temperature and which is applied to the value of the first term instantaneous oil consumption calculated by the calculation means 6 from cartography of the figure 2 .

In the end, the algorithm of the calculation means 6 makes it possible to calculate a second oil consumption term that operates a correction of the first term of instantaneous oil consumption of the engine, for example by linear interpolation of data contained in the maps of the engine. Figures 3 and 4 contained respectively in the memories 8, 9, and this, so as to produce the calculated value of the instantaneous oil consumption of the engine.

The table of the figure 5 provides an example of different values of instant oil consumption CsH of a motor calculated by the calculation unit 1 as a function of different values of the operating speed in revolutions / min and the load expressed as a percentage of the engine and after correction instantaneous oil consumption from the various water and oil temperature values of this engine.

The calculation unit 1 further comprises a counter 10 and a calculation means 11 making it possible to determine in real time the quantity of oil consumed, for example by summing, using an integrator not shown, the different calculated values. Instant oil consumption. This calculation means 11 also makes it possible to determine in real time the quantity of oil remaining in the engine by subtracting between the quantity of oil initially present in the engine and the consumed quantity calculated by the calculation means 11.

The output of the calculating means 11 of the calculation unit 1 can be connected to a means for displaying the quantity of oil remaining in the engine of the vehicle as the instant oil consumption calculated by this unit. Preferably, the calculation unit unit 1 and display means is integrated in the dashboard of the vehicle, the unit 1 then forming part of the onboard computer of this vehicle.

Of course, the functional block diagram of the calculation unit 1 is given only as an example and this unit can be constituted simply by a microprocessor whose algorithm performs the same calculations as those described above.

The device of the invention thus makes it possible to accurately calculate in real time the quantity or volume of oil remaining in the engine without using measuring means. This prediction accuracy of the engine oil level therefore makes it possible to display a reliable value of this level to the driver of the vehicle who is no longer forced to manually check this level by a conventional gauge.

The computing unit 1 of the device of the invention also receives, according to an alternative embodiment of the non-limiting invention of the invention shown in FIG. figure 1b , electronic sensor signals 12, only one of which is shown, for measuring the oil level in the crankcase of the engine. For example, for a turbocharged diesel engine with a displacement of 1.6 liters and having an oil pan that can receive four liters of oil, six oil level measuring sensors can be provided, thus giving a measurement accuracy of this level of about 0.7 liter in absolute value.

The sensors 12 may be connected to another calculation means 13 of the calculation unit 1 making it possible to determine the volume of oil remaining in the crankcase from the measurement sensors 12. In addition, the calculation means 13, under the control of the algorithm of the calculation unit 1, makes it possible to compare the remaining oil volume calculated by the calculation means 11 with the remaining oil volume measured by the sensors 12 and to provide information relating to a abnormal oil consumption, positive or negative, depending on an abnormal decrease or increase in the volume of oil, in the event of a difference between the remaining volumes of oil calculated and measured greater than a predetermined value.

If it is considered that the calculation accuracy of the remaining oil volume estimated from the engine operating parameters is less than 20%, the predetermined difference value mentioned above can be set at 20%. In the example previously given, this gap or failure criterion would then be 20% of 0.7 liter, or 0.14 liter.

Under these conditions, when the algorithm of the calculation unit 1 has estimated by calculation a consumption of 0,84 liter (0,7 liter + 0,14 liter) and that the sensors of measurement 12 did not indicate that the level of oil fell of a slice or stage of 0,7 liter, one considers then that there is a lower oil consumption than normal and, therefore, that there is a risk of increasing the volume of lubricating oil due to the passage of gas oil in the oil diluting the latter.

Conversely, if one of the measurement sensors 12 indicates that the oil level of the crankcase has dropped by one slice or step of 0.7 liter and that the algorithm of the calculation unit 1 has estimated by calculation oil consumption of less than 0.56 liter (0.7 liter - 0.14 liter), it is considered that there is excessive oil consumption which may be due to oil leakage due to a leakage or deterioration of some engine components, which may lead to breakage of the latter.

The calculation unit 1 can then provide the display means of the vehicle dashboard with information relating to a drift in oil consumption, that is to say a decrease or an abnormal increase in the volume of the vehicle. oil. This information can be signaled on the dashboard of the vehicle by a light or sound signal prompting the driver of the vehicle to go to a convenience store before a serious breakdown occurs.

Of course, the functional block diagram of the calculation unit 1 is given only as an example and this unit can be constituted simply by a microprocessor whose algorithm performs the same calculations as those described above.

The general principle of the invention according to the variant which has just been described with regard to the figure 1b is therefore to determine continuously (in real time) from a calculation the volume of oil remaining in the crankcase of an internal combustion engine, for example of the turbocharged diesel type during normal operation of this engine, to be measured at from oil level sensors, the volume of oil remaining in the oil sump, compare the remaining oil volumes calculated and measured, and provide information on abnormal oil consumption in the event of a discrepancy between the remaining oil volumes calculated and measured greater than a predetermined value.

• il permet au propriétaire du véhicule de diagnostiquer une dérive de consommation d'huile anormale du moteur de son véhicule pour l'inciter à faire réparer le moteur avant une panne,
• il permet au véhicule de disposer d'un moyen de diagnostic très fiable d'une défaillance du moteur liée à l'huile de lubrification,
• il permet de gérer automatiquement les intervalles de vidange grâce au suivi extrêmement précis du niveau d'huile et de fournir un signal indiquant qu'une vidange doit être effectuée pour éviter une casse du moteur.

The device of the invention according to this variant embodiment has the following advantages:

• it allows the vehicle owner to diagnose abnormal oil consumption drift from the engine of his vehicle to encourage him to have the engine repaired before a breakdown,
• it allows the vehicle to have a very reliable diagnostic means of an engine failure related to the lubricating oil,
• it allows to automatically manage the emptying intervals thanks to the extremely precise monitoring of the oil level and to provide a signal indicating that an emptying must be carried out to avoid a breakage of the engine.

In addition, the device of the invention makes it possible to accurately determine the intervals of emptying of the lubricating oil by accurately monitoring the oil level and, therefore, prevents the owner of the vehicle from performing a premature emptying or late.

The device of the invention according to another variant embodiment which will be described with reference to figures 1c , 6 and 7 is in fact adapted to predict or estimate the emptying interval of the lubricating oil of a internal combustion engine of a vehicle, such as for example a turbocharged diesel engine, from the oil consumption calculated by this device and according to the type of oil used in the engine of the vehicle and that the device is suitable to be determined from means that will be described below.

The algorithm of the calculation unit 1 can in fact also be adapted to take into account the type of oil used in the engine when calculating the oil consumption of this engine.

An embodiment allowing the algorithm of the calculation unit 1 to predict the type of oil used in the engine is to measure by a sensor 14 the oil pressure of the engine oil pump, from which pressure can be measured the viscosity of the oil.

Indeed, an engine oil pump comprises a control valve which opens from a certain pressure level. The main condition of pressure-viscosity linearity of the pump oil is to have a pump in an unregulated operating zone. The control valve will be open for temperatures that are too cold and motor operating speeds that are too high.

The figure 6 represents a graph of the relationship between the oil pressure P measured by the sensor 14 at the outlet of the oil pump and the viscosity of the oil Vi at various constant rotation speeds ω 1, ω 2, ω 3 expressed in revolutions per minute. This graph may be stored in a memory of a calculation means 15 of the unit 1 connected on the one hand to the calculation means 11 and on the other hand to the sensor 14 for measuring the oil pressure of the pump. oil.

Thus, the calculation means 15 is able, under the control of the algorithm of the calculation unit 1, to measure the viscosity of the oil from the oil pressure of the engine oil pump and, depending on the measurement of this viscosity, in deduce the type of oil used in the engine and the grade of this oil.

Another embodiment for predicting the type of oil used in the engine is to determine the chemical constitution of the lubricating oil from on-vehicle sensors and to perform mass spectrometry. The information relating to these sensors can be transmitted to the algorithm of the calculation unit 1 by means of the calculation means 15 to determine the overall constitution of the oil and to deduce the type of oil used by comparing it. a database included for example in the calculation means 15 of the unit 1 and relating to various chemical constitutions of different oils.

Thus, the algorithm of the calculation unit 1 allows the latter to output a continuous adaptation information of the emptying interval of the lubricating oil according to the conditions of use of the engine of the vehicle, for example at high load or low load, and the type of oil used in the engine and predicted by the various sensors mentioned above.

In this way, the device of the invention allows to predict the oil change interval even if the previous emptying was carried out in a network outside that of the car manufacturer using an oil different from that recommended by this manufacturer, thanks to the sensors used to predict the type of oil present in the engine of the vehicle.

If the vehicle is not equipped with sensors for the detection of the type of oil used in the engine of this vehicle, and for oil changes carried out in the manufacturer's network, the person in charge of this network can simply load into the algorithm of the unit of calculation 1 the information relating to the type of oil that it will use during the emptying so that the algorithm of this unit can take into account the type of oil used to predict the optimal moment of the next oil change. for example, telling the driver how much he can still drive with his vehicle before proceeding with the next oil change.

The block diagram of the figure 7 takes a known architecture of a device for evaluating the aging properties of a lubricating oil of an internal combustion engine.

Such a device is described in the patent US 6,253,601 . This device makes it possible in general to evaluate the properties of the oil by a computer 714 operating under the control of an algorithm, from different sensors 715, 716, 717 and as a function of measured engine operating parameters. such as those from the sensors of the operating mode 72, the load 73, measuring the cooling water temperature 74 and measuring the oil temperature 75 of the engine.

When the information relating to this evaluation indicates that certain criteria come out of intervals of validity, the algorithm of the computer 714 recommends the change of oil. This emptying algorithm is based on the aging of the properties of the oil. Preference will therefore be made to this patent US 6,253,601 to understand how aging properties of oil are evaluated to alert the driver of the vehicle of the optimum moment at which it must carry out the oil change of the engine of its vehicle.

This alerting information is supplied to a display means 718 connected to the computer 714 and which may be the one connected to the aforementioned calculation unit 1. The sensors 715, 716 and 717 can be respectively an oil level sensor, a soot sensor and a viscosity sensor.

The remaining amount of oil in the crankcase, calculated as indicated above with reference to the figure 1 , modifies the aging analysis of the properties of the oil as it was carried out in the patent description US 6,253,601 .

Indeed, the chemical aging rate of the lubricating oil, linked for example to the percentage of carbon and / or fuel present in this oil and to the viscosity thereof, is proportional to the amount of the lubricating oil. lubrication. Therefore, the evolution of the characteristics of the lubricating oil measured by the sensors and the models described in the patent US 6,253,601 between each measurement time step is to be weighted by a multiplying factor depending on the amount of lubricating oil remaining in the crankcase of the engine.

So, for example, if a sensor used in the device of the figure 7 patent US 6,253,601 indicates that between the time T and the time T + 1 the percentage of carbon in the lubricating oil has increased by n%, the algorithm of the calculation unit 1 that can be used in the calculator 714 adds to this evolution of carbon percentage between T and T + 1 the evolution of the quantity of oil calculated by the algorithm which can then estimate that between the time T + 1 and the time T + 2 the evolution the percentage of carbon will be proportional to the ratio of the quantities or volumes of oil to T + 2 and T + 1, ie a predicted percentage change of carbon in the oil of (n + 1)% = n% * volume of oil at T + 2 / volume of oil at T + 1.

Thus, by periodically measuring the aging evolution of the properties of the lubricating oil and weighting this measurement by a coefficient which is a function of the remaining quantity of the calculated oil, the driver is informed that he must perform a draining of the lubricating oil. the engine oil of his vehicle when the weighted measurement reaches a critical value.

The device of the invention describes according to the variant embodiment of the figure 1c , thus allows to adapt the intervals of lubricant draining of a vehicle according to both the conditions of use of the vehicle, the type of engine and the type of oil used during a draining of the vehicle and without must add physical means (sensors) to measure the oil consumption which is estimated by calculation with an uncertainty of less than 20%.

The unit with calculation unit and display means of the device of the invention is advantageously integrated into the dashboard of the vehicle, the computing unit can then be part of the vehicle's on-board computer.

Of course, the functional block diagram of the calculation unit 1 is given only by way of example and this unit can be constituted simply by a microprocessor or by a calculator of the kind of the figure 7 and whose algorithm performs the same calculations as those described above.

• il permet d'adapter automatiquement les intervalles de vidange de lubrifiant d'un véhicule, d'où un gain économique,
• il permet l'utilisation de plusieurs types d'huile et peut, par conséquent, éviter au propriétaire d'un véhicule d'être lié à un fabricant d'huile, d'où également un gain économique, et
• il permet d'être indépendant des lieux de vidanges, tels que ceux faisant partie du réseau du constructeur ou ceux constitués par des garages indépendants non liés aux constructeurs, ou tout simplement ceux où le propriétaire du véhicule effectue de lui-même la vidange d'huile qui peut, par ailleurs, être effectuée sans problème à l'étranger avec d'autres types d'huile, d'où un gain technique.

The device of the invention according to the embodiment of the figure 1c therefore has the following advantages:

• it makes it possible to automatically adapt the intervals of lubricant draining of a vehicle, resulting in an economic gain,
• it allows the use of several types of oil and can, therefore, prevent the owner of a vehicle from being linked to an oil manufacturer, hence also an economic gain, and
• it makes it possible to be independent of the emptying places, such as those forming part of the manufacturer's network or those constituted by independent garages not related to the builders, or quite simply those where the owner of the vehicle carries out himself the emptying of oil which can, besides, be carried out without problem abroad with other types of oil, from where a technical gain.

Claims (12)

1. Device for estimating the consumption of oil of a vehicle engine, comprising a calculation unit (1) cooperating with means for determining the values taken by predetermined functioning parameters of the engine comprising the functioning rate of the engine, the load of the engine, the temperature of cooling water of the engine and the temperature of the oil of the engine, the said determining means being such as measurement sensors (2, 3, 4, 5) or the on-board computer of the vehicle, characterized in that the calculation unit (1) comprises an algorithm permitting the calculation, for a given functioning period, of a first consumption term of oil of the engine as a function of the values of the functioning rate and of the load of the engine during this period, and the calculation, from the values of water and oil temperature, of a second consumption term of oil of the engine to apply to the said first term, to deduce therefrom the estimation of the oil consumption which is sought.
2. Device according to Claim 1, characterized in that the calculation unit (1) comprises a memory (7) containing a cartography of the consumption of oil of the engine as a function of the rate and of the load of the engine and the algorithm of this unit permits the calculation of the said first consumption term of oil of the engine by linear interpolation of the data contained in the stored cartography.
3. Device according to one of Claims 1 to 2, characterized in that the calculation unit (1) comprises a memory (8) containing a cartography of the consumption of oil of the engine as a function of the rate and of the load of the engine for different temperatures of water of the engine, and a memory (9) containing a cartography of the consumption of oil of the engine as a function of the rate and of the load of the engine for different oil temperatures of the engine and the algorithm of the calculation unit (1) permits a calculation of the said second consumption term of oil of the engine by linear interpolation of the data contained in the stored cartographies.
4. Device according to one of the preceding claims, characterized in that the algorithm of the calculation unit (1) also permits a deduction from a given quantity of oil, the estimated consumption of oil for determining the quantity of oil remaining in the engine.
5. Device according to Claim 4, characterized in that the calculation unit (1) additionally cooperates with measurement means (12) of the oil level in the engine providing a measurement of the volume of oil remaining in this engine, and in that the algorithm of the calculation unit permits a comparison of the calculated volume of remaining oil with the measured volume of remaining oil, and a provision of information relating to an abnormal consumption of oil in the case of a difference between the volumes of remaining oil calculated and measured which is greater than a predetermined value.
6. Device according to Claim 5, characterized in that the measurement means of the oil level are sensors (12) of the electronic type and measure levels of oil by levels, the number of which depends on the number of sensors which are used.
7. Device according to any one of Claims 4 to 6, characterized in that the algorithm of the calculation unit (1) permitting a calculation of the remaining quantity of oil is adapted as a function of the type of oil which is used in the engine, and allows a control of the warning means of the driver of the vehicle to carry out an emptying of the oil when the quantity of oil remaining in the engine and calculated as a function of the type of oil which is used reaches a critical value.
8. Device according to Claim 7, characterized in that the calculation unit (1) comprises a memory containing linear relationship curves, at various constant functioning rates of the engine, between the viscosity of the oil and the oil pressure of the oil pump of the engine and the algorithm is able to determine the type of oil used in the engine from the measurement of the viscosity of the oil obtained as a function of the oil pressure of the oil pump according to the functioning rate of the engine.
9. Device according to Claim 7, characterized in that it comprises sensors (14) on board the vehicle, permitting a mass spectrometry to be carried out to determine the chemical constitution of the oil, and the algorithm is able to deduce the type of oil used in the engine by comparison with a database of a memory of the calculation unit (1) and relative to various chemical constitutions of different oils.
10. Device according to one of Claims 7 to 9, characterized in that it comprises sensors (715-717) and models from which the algorithm is able to measure periodically the aging evolution of the properties of the oil and to balance this measurement by a coefficient which is a function of the calculated remaining quantity of oil.
11. Device according to any one of Claims 4 to 10, characterized in that it comprises a display means of at least one item of information from the following items of information: the calculated quantity of oil remaining in the engine and possibly, the measured quantity of oil, the information relating to an abnormal consumption of oil of the engine, a warning to carry out an emptying operation, the remaining mileage of the vehicle for carrying out the emptying of the oil.
12. Device according to one of the preceding claims, characterized in that it is integrated in the on-board computer of the vehicle.

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