FR2985316A1 - Method for external diagnosis of malfunction of e.g. lubricant additive, additivation device in vehicle's diesel engine, involves analyzing variation between measured and theoretical additive contents with respect to maximum variation - Google Patents

Abstract

The method involves analyzing a fuel in a tank of a vehicle to measure an additive content in the fuel by a spectrometer associated with optical fiber and probe placed in the tank by using spectroscopic analysis technique after additivation request, where the additive is in form of suspension or colloidal dispersion of nano-particles. The measured additive content is compared with theoretical content. Variation between the measured content and the theoretical content is analyzed with respect to maximum variation authorized for the additive content.

Description

The invention relates to a method for the external diagnosis of the malfunction of a device for additive additive in a fuel. for an internal combustion engine vehicle. The new engine technologies, such as diesel engines with Common Rail 10 system and very high pressure fuel injection or gasoline direct injection engines are very efficient but very sensitive to fuel quality. Thus, there is a benefit in using a fuel containing additives improving its quality, including additives for improving the distribution of fuel in the engine, engine performance enhancement additives and fuel additives. improving the stability of the engine operation. These are, for example, detergent agents, lubricating additives or anticorrosive additives. However, the quality of commercially available fuels does not always provide fuel for the engine with a fuel containing sufficient additives. In addition, fuels worldwide respond to more or less demanding standards and therefore have a variable quality. There is therefore interest for optimum operation of the engine to adjust the concentration of additive contained in the fuel. In addition, in order to meet the new emission control standards for vehicles, particularly diesel vehicles, the vehicles are progressively equipped with particulate filter (FAP) type of pollution control means. This is already the case in Europe since the advent of the Euro 5 standard. In most cases, a catalyst is used to help burn soot periodically and thus regenerate the FAP. The use of a FAP regeneration additive, vectorized by the fuel supplying the engine or "Fuel Borne Catalyst" (FBC), has proved to meet many criteria since it makes it possible to regenerate the FAP more quickly and efficiently. at lower temperatures than the competing technology called Catalysed Soot Filter (CSF) or Catalyzed Particulate Filter (C-DPF). It is therefore advantageous to equip the vehicle with an on-board device for introducing into the fuel an additive to aid the regeneration of the FAP and / or fuel additives improving the quality of the fuel and / or the operation of the engine and / or its durability. It is known that there are systems for introducing such additives into the fuel, in particular catalytic additives FBC for assisting the regeneration of particulate filters. These systems are generally based on a large tank, 1 to 3 liters minimum volume, containing the additive reserve and must be installed in areas close to the fuel tank. The dosage of the additive is then generally performed using high precision metering pumps controlled by an additional electronic central unit (ECU). This metering device is finely managed to ensure an additive content in the fuel sufficient to allow a good regeneration of the FAP, but not too excessive to avoid premature fouling of the FAP due to the mineral residues of regeneration of the FAP which remain collected within it. Conventionally when the fuel level increases in the tank, following the addition of fuel, a calculator indicates to the pump the amount of additive to be injected into the tank so as to maintain a constant additive concentration in the fuel and this to any time.

All of these devices (pump / reservoir) have no means to easily detect a malfunction of the device. By malfunction, it can be understood that the device does not deliver an additive contrary to the instruction that is required for example following the addition of fuel when the additivation is enslaved to this parameter. It can also be understood by dysfunction that the amount additive is significantly different from the theoretical amount to be injected. Malfunctions can have multiple origins such as a defect on a standard equipment (pump, ECU ...) or a bad connection or connection of the entire device. In these cases, the malfunction appears from the first additivation request. There are many other possible causes that could cause the device to malfunction. In the event of a malfunction, the devices currently in place do not generally identify in a direct way the failure of the additive system. The vehicle ECU for example in the case of a BCF detect a failure of the pollution control system, including poor regeneration of the FAP without identifying the true cause of the failure that is to say a bad additivation or absence additivation.

Moreover, the detection can be done after a more or less long period of time after the defective additivation: typically in the example given for the regeneration of the FAP, the dysfunction will be identified after the regeneration of the FAP, so typically after more than 500 to 700 km or several hours after the additivation, or only after several requests for regeneration of the FAP. In this example, this lack of additivation can have serious consequences such as the destruction of the FAP and generate significant costs of compliance.

In contrast, an excess of FBC additive will not be detected during regenerations of the FAP since it will regenerate without difficulty. The defect will only occur after a journey of several tens of thousands of kilometers from the vehicle when the FAP will be prematurely obstructed by an excess of ash from the residual BCF in the FAP after soot combustion. The same is true for other fuel additives: in this case the detection is even more difficult because many other parameters can influence the operation of the engine. The consequences, for example on the deterioration of high-pressure pumps or high-pressure injectors, are nonetheless very important and costly in the case where these devices have to be replaced. There is therefore a need to be able to quickly detect a defect of the vehicle additive system: it means quickly to be able to detect the failure from the first injection, especially on the production plant or assembly of the vehicle or before the vehicle is delivered to the customer. There is also interest in determining whether the dysfunction corresponds to a lack of injection or to a difference between the quantity injected and the quantity theoretically injected. This helps in diagnosing the failure and implementing the corrective action (s) more quickly and / or more efficiently. There is also a need in the maintenance or the repair of the system in the concession and in the car repair shop, for example after adding FBC in its specific tank (refilling) in the case of a vehicle with FAP, or after replacing the fuel tank due to an accident or rupture of its wall, or after changing the additive dosing pump on the vehicle for example.

More generally, there is a need in case of failure, including alerting via the On Board Diagnostic (OBD) system such as for example the OBD of the pollution control line, to determine whether additivation is involved. The object of the invention is therefore to meet these needs. For this purpose, the method according to the invention is a method for the external diagnosis of the malfunction of a device for adding at least one additive in a fuel for a vehicle with an internal combustion engine and it is characterized in that It comprises the following steps: (a) a fuel analysis step for measuring the additive content in the fuel; - (b) a comparison step between the additive content measured in the previous step and a theoretical content; (c) a step of analyzing the difference between the measured content and the theoretical content with respect to the maximum permissible deviation for the additive content. This method has the advantage of being easily implemented at any time and with a device whose operation is simple. Other characteristics, details and advantages of the invention will appear even more completely on reading the description which follows, as well as a concrete but nonlimiting example intended to illustrate it. This method of the invention is suitable for all fuel additive and additive storage systems and devices such as: additive systems comprising a rigid or flexible additive reservoir, a metering pump, additive and a calculator for determining and introducing the additive into the fuel in a controlled manner, based on the data available on the vehicle. An additive system of this type is described in US patent application 2008/0037908 for example; the storage and additive systems integrated into the perimeter of the fuel filter as described in patent applications US Pat. No. 6,638,554; US 2009/0101561 and US 2001/0000400 in particular; storage and additive systems which are connected directly to the fuel line and out of the perimeters described above, for example integrated directly into the fuel line as described in US Pat. No. 6,827,750 for example. The process of the invention is also applicable to the various forms of additives, whether they are used in the form of a liquid vector, more or less viscous, or in the form of gels or solid dispersible or soluble in fuels used with a speed of solubility or dispersibility more or less controlled. The process of the invention comprises a first step, step (a), in which the fuel is analyzed in order to measure its additive content.

As will be seen below, the analysis may not be based on a direct measurement of the additive content in the fuel but on an indirect measurement, that is to say on the measurement of a characteristic or a fuel parameter that is correlated with this content, for example the absorbance of radiation by the fuel.

In a second step, step (b), comparing the results of the measurement in the previous step with a theoretical value so as to highlight a possible difference between the measured value and the theoretical value. The last step, step (c), is a step of analysis of the difference between the measured content and the theoretical content with respect to the maximum permissible deviation for the additive content. By analysis step means on the one hand the detection of a deviation and on the other hand the verification that this difference is greater than or not a maximum value of deviation, set beforehand. If this difference is greater than the maximum value mentioned above, the method of the invention may then comprise an alerting step. This maximum value set is that beyond which it is considered that there is a malfunction and is determinable by the skilled person: it depends in particular on the type of additive used, the sensitivity of the chosen detection device, the type of vehicle and / or engine, the type of engine technology, the type of fuel used by the vehicle, in particular the standard in force in the geographical area of use of the vehicle, the pollution control technology, in particular the type when a difference is observed between the measured value and the theoretical value and that this difference is greater than the maximum value of deviation tolerated, the additive device of the vehicle is considered to be faulty. The vehicle can then be isolated from other vehicles and corrective actions can be taken to remedy the failure. Once the corrective actions have been carried out, an additive request is requested from the vehicle and then a second series of analysis is started to ensure that the additive is in accordance with the objective and that the failure has been corrected. The method can be applied at defined frequency and / or event.

The method of the invention is an external diagnostic method, which means that it is not implemented with a device on the vehicle. Thus according to a first embodiment, this method is applied in a vehicle assembly plant, particularly at the end of the assembly line and can be inserted into the series of tests performed on the vehicle at the end of the assembly line. According to another embodiment, the method of the invention is applied in a dealership where the vehicles are sold or in an automobile repair shop and it can be used to diagnose a possible failure of the additive system or to control it. smooth operation following a modification. Any analytical technique for detecting the presence, amount of additive and / or variation of this amount in the fuel may be used. The choice of this technique will depend on the additive and the fuel. However, and according to a particular embodiment, the analysis of the fuel is done by a spectroscopic analysis technique. More specifically, the detection and measurement of a quantity of additive in the fuel is based on a spectroscopic method using infra-red technology: near infra-red (typically 780 to 1400 nm), medium infra-red ( typically 1400 to 3000 nm) or far infra-red (typically 3000 to 1 000 000 nm), visible (typically 780 to 380 nm), near ultraviolet (380-200 nm) or extreme ultraviolet (200 -100 nm). Preferably, close infra-red (or PIR), visible or near ultraviolet spectroscopy will be used in the wavelength range between 190 and 2500 nm. Indeed these spectroscopies are well suited to the analysis of fuels and they can be implemented for analytical methods that are very sensitive to a change in fuel composition. Devices for spectroscopic analysis generally include: - a lighting device configured to generate a light beam covering the chosen wavelength range; a probe configured so that the light beam coming from the lighting device interacts with the fuel to be analyzed; A spectral analysis device configured to receive the light beam after interacting with the fuel to be analyzed and to provide measurements as a function of a quantity of light received for different wavelength ranges.

According to a preferred embodiment, the analysis device is designed to operate at a specific wavelength, wavelength selected with regard to the type of additive and the type of fuel (in particular gasoline or diesel) and making it possible to develop a maximum signal difference between the additive fuel and the non-additive fuel. Such devices are for example described in WO 2009/047605, WO 2009/047607 or WO 2009/047608. These technologies make it possible to use spectrometers without moving parts of the dispersive network type, transformed Fourrier, emitting diodes or others. They can also be miniaturized and the transmission and detection systems can be connected to one another via optical fibers. Thus these technologies are easily integrated in a factory, a workshop-repair or a car dealership. They are also robust and low cost.

According to a preferred embodiment, the fuel analysis device is a monolong wave visible spectroscopy device, typically 780 to 380 nm. There are such devices that are compact, very simple to use, especially for people with no particular knowledge in analysis or chemistry, and low cost.

It should be noted that the method of the invention is particularly applicable to vehicles whose engines use gasoline or diesel fuel. These fuels may contain fractions of biofuels, including bioalcohols such as bioethanol, vegetable oils, fatty esters of vegetable oils such as fatty acid methyl esters meeting the EN14214 standard. The method of the invention may be used more particularly in the case where the additive is a regeneration additive particulate filters including FBC type. As indicated above, this method applies to vehicles equipped with a device for dispensing an additive in a fuel circulation circuit of the vehicle engine. The method of the invention is used to control the operation of the additive dispensing device of a new vehicle that is to say in the very first hours of operation of the vehicle or more generally to control the operation of the device for dispensing the additive of a vehicle. In the case of a new vehicle, preferably, this method is implemented as soon as the first additivation is requested, ideally from the end of manufacture of the vehicle. This check can be done at any time, including either on the assembly plant or in a dealership before handing over the vehicle, as indicated above. It should be noted that this method also applies to the case of a vehicle called "retrofitted". Retrofitté means a vehicle having already rolled which is modified to equip it with a device for dispensing an additive in its fuel circulation circuit. It is also understood by retrofitted, a vehicle equipped with a device for dispensing an additive in its fuel circulation circuit having already rolled but for which the device for dispensing the additive and / or the additive and / or its setting has been changed.

In addition, the vehicles may be so-called "off road" vehicles, such as construction machinery, or so-called "on road" vehicles, such as motor vehicles. The analysis apparatus for detecting the presence, the amount of additive and / or the variation of this quantity in the fuel will therefore be installed near the place where it is desired to control the operation of the additive device . Particularly in the case of a control on the manufacturing plant and / or assembly of the vehicle, the measuring device can be installed in particular either in a central laboratory of the plant or installed at the edge of the assembly line, particularly in end of assembly line in the area where the vehicle checks are carried out. The device can also be installed in a repair shop or a dealership to carry out a control of the additive system before delivery of the vehicle. This case is particularly interesting in the case of a retrofit of the vehicle but also as a result of maintenance or repair on the storage system and dosing additives. This method can also be used in a repair shop or a concession to help diagnose a failure, including a failure of the pollution control system, in the case of a vehicle equipped with an additive introduction device or a vehicle running a manual additive additive (as in the case of the addition of "pod" directly into the tank by the user). The method can be implemented according to different variants which will be described below. Thus, the method may comprise, prior to step (a), a step of sampling a fuel sample from the vehicle tank. The volume of the sample taken will depend on the volume necessary to carry out the analysis and therefore on the chosen analysis. Generally less than 100 ml is sufficient for most analyzes. The analysis of step (a) is then performed on the sample thus taken. According to another variant, the method comprises, after the step (a) mentioned above - a step (a1) of additivation request to the additive device; a step (a2) for analyzing the fuel after the additivation request; a step (a3) of calculating the additive content added in step (a1) by the difference between the fuel analysis before and after additivation; the step (b) above being a comparison step between the additive content measured after step (a3) and a theoretical content. In the case of this variant, it is also possible to carry out a step of sampling a fuel sample from the vehicle tank prior to step (a). According to yet another variant, the step of sampling a fuel sample from the vehicle tank may be omitted in the case of an on-line analysis of the presence or the concentration of additive, particularly in the case of an analysis based on optical spectroscopy preferably by infrared, near infrared, visible or ultraviolet. In order to avoid sampling, the analysis can be done either online by a miniaturized device at the outlet of the tank to the engine supply or directly into the tank of the vehicle. The measuring device is then for example composed of a spectrometer, Ocean Optics or Ayantes type or any spectrometer capable of either measuring at a fixed wavelength or the full spectrum, associated with a sufficient optical fiber in length to place in the tank a probe allowing measurement in situ. The probe will preferably be a transmission probe. This measure will make it possible to determine the correct operation of the additive addition assembly and to eliminate any sampling and any manipulation of fuel, which makes it possible to carry out the process according to the invention at any location without resorting to precautions / installations guaranteeing correct conditions for handling fuel. The process employing the above-mentioned steps (a), (b), (c) can be used more particularly in the case where the characteristics of the fuel present in the tank of the vehicle are known, which is the case of control on factory assembly lines. In the case of using a spectroscopic analysis technique, the essence of the fuel is essentially its absorbance in the length range used.

The process according to the variant implementing the above steps (a1), (a2) and (a3), will preferably be used in the case where the characteristics of the fuel present in the reservoir are not known, which can be the case especially in the repair shops. The different additives that can be used by the dispensing device according to the invention will now be more particularly described, these additives being well known in the technical field concerned here. These additives can be classified into two categories: on the one hand, those which have a catalytic function of assisting the regeneration of particulate filters, and, on the other hand, those which have a function other than a catalytic function, such as improvement of the fuel distribution in the engine, additives for improving the performance of the engine operation, additives for improving the stability of the operation of the engine. The additives used are generally in liquid form and may consist of a liquid or a mixture of liquids, a colloidal suspension in a liquid base, or in the form of a gel whose viscosity permits the flow of the liquid. 'additive. However, solid additives can also be used which will gradually dissolve or disintegrate to release the amount of additive needed in the fuel. Regeneration aid additives These additives are ideally liquid in the operating temperature range, generally between 20 and 45 ° C but they can also be in another physical form such as a gel or a solid. These additives may contain any type of catalyst effective to catalyze the combustion of soot including platinum, strontium, sodium, manganese, cerium, iron and / or their combination. The amount of additive required in the fuel is generally at least about 1 ppm and at most about 100 ppm, this amount being expressed as the weight of the metal additive element relative to the fuel weight. These additives may be in the form of an organometallic salt or a mixture of organometallic salts which are soluble or dispersible in the fuel. These salts are characterized in that they comprise at least one metal part and a complexing organic part generally of acid origin, all suspended in a solvent.

The BCF additives may also be in the form of an organometallic complex or a mixture of organometallic complexes soluble or dispersible in the fuel. These complexes are characterized in that they comprise at least one metal part and at least two organic complexing parts. Such a product is for example described in GB 2,254,610. Also, the FBC additives may also be in the form of a colloidal suspension or dispersion of nanoparticles, for example amorphous or crystalline metal oxide or oxyhydroxide.

The term "colloidal dispersion" designates in the present description any system consisting of fine solid particles of colloidal dimensions based on the additive, in suspension in a liquid phase, said particles possibly also possibly containing residual amounts of bound or adsorbed ions such as, for example, nitrates, acetates, citrates, ammoniums or chlorides. By colloidal dimensions is meant dimensions of between about 1 nm and about 500 nm. These particles may more particularly have an average size of at most 100 nm and even more particularly of at most 20 nm. In the case of BCF additives in the form of a colloidal dispersion, the particles may be based on a rare earth and / or a metal selected from groups IIA, IVA, VIIA, VIII, IB, IIB, IIIB and IVB of the periodic table. Rare earth means the elements of the group constituted by yttrium and the elements of the periodic classification of atomic number inclusive between 57 and 71.

The periodic table of elements to which reference is made is that published in the Supplement to the Bulletin of the Chemical Society of France No. 1 (January 1966). For these additives that may be used in the form of a colloidal dispersion, the rare earth may be chosen more particularly from cerium, lanthanum, yttrium, neodymium, gadolinium and praseodymium. Cerium can be chosen especially. The metal may be selected from zirconium, iron, copper, gallium, palladium and manganese. Iron can be chosen especially. The iron may be in the form of an amorphous or crystalline compound.

Colloidal dispersions based on a combination of cerium and iron may also be mentioned more particularly. The colloidal dispersions can comprise more particularly: an organic phase, particles of the additive, of the type described above (in particular rare earth and / or a metal chosen from groups IIA, IVA, VIIA, VIII, 113, IIB, IIIB and IVB), suspended in the organic phase; at least one amphiphilic agent.

These colloidal dispersions may especially contain an additive based on iron or an iron compound. The colloidal dispersions may be in various embodiments described in particular the following patent applications: EP 671 205, WO 97/19022, WO 01/10545, WO 03/053560, WO 2008/116550.

The other additives Other types of known additives, different from the BCFs and which have a function other than a catalytic function, can also be injected into the circulation circuit. These additives allow the improvement of the fuel distribution in the engine and / or the improvement of the performance of the engine operation and / or the improvement of the stability of the operation of the engine. Among the additives for improving the fuel distribution in the engine are, for example, anti-foam additives, such as organosilicones, de-icing additives, such as low molecular weight alcohols or glycols. Other additives are those improving the operation of the cold engine. These include polymeric additives that reduce the temperature at which fuel is cloudy or freeze, flow-promoting additives, such as high molecular weight polymers that reduce turbulence in fluids, and can increase throughput by 20 to 40 percent. . Corrosion inhibiting additives may also be used. Engine performance improvement additives may also be used, such as procetane additives, prooctane additives, smoke inhibiting additives, friction loss reducing additives called FM additives for "Friction Modify" or "additive" additives. extreme pressure. . Detergent additives intended to limit any deposit at the injectors can also be used. The fuel can form deposits in the fuel system, especially at the high-pressure fuel injectors and especially at the holes of the injectors. The extent of deposition formation varies with the design of the engine, including the characteristics of the injectors, the fuel composition and the composition of the oil used to lubricate the engine. In addition, these detergents are also effective in reducing the negative impact of the presence of metal compounds in the fuel such as zinc or copper that may arise from contamination of the fuel distribution system, for example, or traces of compounds. from the process of synthesis of fatty acid esters. Excessive deposits can alter the aerodynamics of, for example, the jet of fuel from the injector, which in turn can impede the air-fuel mixture. In some cases this results in overconsumption of fuel, loss of engine power and increased pollutant emissions. Detergent additives have the particularity of dissolving already formed deposits and reducing the formation of deposit precursors, in order to avoid the formation of new deposits. An example of a detergent additive is, for example, described in WO 2010/150040.

Additives for improving the lubricating power can also be used to avoid wear or seizure of the high-pressure pumps and injectors, the lubricating power of the fuels being poor. They contain a polar group that is attracted to the metal surfaces to form a protective film on the surface.

Additives for improving the operating stability of the engines can be envisaged. Indeed, the instability of fuels causes the formation of gums that participate in the fouling of the injectors, the clogging of the fuel filter and fouling of the pumps and the injection system.

The following additives can also be used: antioxidant type additives; stabilizing additives; metal deactivating additives to neutralize the catalytic effects of certain metals; dispersant additives for dispersing the formed particles and preventing agglomeration of rather large particles. According to a particular embodiment, the additive is a combination of a detergent additive and a lubricating additive, and possibly a corrosion inhibiting additive.

In the case of a vehicle equipped with a FAP, it will be advantageous to associate with an additive type FBC at least one detergent type performance fuel additive as described in the patent application WO 2010/150040.

In the case of a vehicle equipped with a FAP, it will also be advantageous to associate with an additive type FBC several fuel performance additives, especially when the vehicle is marketed in a geographical area where the fuel is of variable quality and / or poor. In the case of a vehicle not equipped with a FAP, different types of additive combinations can be envisaged such as that combining one or more detergents with a lubricating additive and a corrosion inhibitor. In terms of the physical form of the additives on board and stored on the vehicle, mention may be made of liquids (as in the patent application WO 2010/150040), gels (as in the patents US 2004/0261313 and US 7000655) or solids (as described in US Patents 2001/0000400 and US 6835218), with of course a system for storing and dispensing additive in the appropriate fuel. The embodiments specified above are given for information only and are in no way limiting. Those skilled in the art will understand that the invention also relates to embodiments not shown here but resulting from the combination of several previously described modes or the substitution of one or more characteristics by other different and associated characteristics. A concrete example will now be given. EXAMPLE This example describes the implementation of the method using fixed wavenumber visible spectroscopy (500 nm) to detect the presence of FBC type additive in a diesel fuel. The FBC additive used in this example consists of a colloidal suspension of iron-based particles such as the dispersion C of Example 3 of the patent application WO 2010/150040. This catalytic colloidal suspension is typically used in a concentration range to add fuel with an iron concentration of 7 ppm iron (metal) in the fuel to regenerate FAPs of particular vehicles such as those with an engine. Euro 5 with 2 liters of displacement. In this example, 4 different fuels were tested: 35 - a commercial diesel fuel meeting the European standard EN590; - a B10 diesel bio-fuel containing 90% of EN590 diesel fuel and 10% of fatty acid methyl ester (EMAG) biodiesel meeting the EN14214 standard; - a B30 diesel bio-fuel containing 70% diesel fuel EN590 5 and 30% biodiesel based on fatty acid methyl ester (EMAG) meeting the EN14214 standard; - a kerosene cutting fuel corresponding to the NATO RF63 fuel of origin the tanker TOTAL. These fuels were supplemented with a precise amount of BCF additive so as to result in a BCF content in the fuel of 5, 6 or 10 ppm by weight. Each fuel before and after additivation is analyzed by the spectrometer at 500 nm wavelength and the absorbance of the light by the fuel is recorded. These absorbances are reported in the table below. It is found that the fuels without additives have variable Al absorbances between 0.042 and 0.141. In each case, the addition of FBC additive, even in a very small amount, leads to an increase in absorbance (A2, A3 or A4), the increase being all the greater as the amount of FBC added is important. . This shows that a comparison of the absorbance of the fuel at 500 nm before and after additivation makes it possible to detect whether there has been (increase) or not (no increase) additivation. The table also indicates that the difference in absorbance between the additive fuel and the non-additive fuel is, for a fixed additive content, identical regardless of the fuel: typically 0.015-0.016 for 5 ppm iron and 0.031-0.035 for 10 ppm iron, 6 ppm iron leading to intermediate relative absorbance (0.023). The difference is proportional to the additive content in the fuel. Thus, it is clearly possible to detect an excess (or lack) of additivation by the value of the difference in absorbance.

Table Diesel Diesel B10 Diesel B30 Commercial Fuel NATO EN590 RF63 Al = Absorbance 0.141 0.071 0.066 0.042 non-additive fuel A2 = Absorbance 0.156 0.087 - 0.057 fuel at 5 ppm iron A3 = Absorbance - - 0.089 - fuel at 6 ppm iron A4 = Absorbance 0.176 0.104 - 0.073 fuel at 10 ppm iron A2-A1 = Absorbance 0.015 0.016 - 0.015 due 5 ppm iron A3-A1 = Absorbance - - 0.023 - due 6 ppm iron A4-A1 = Absorbance 0.035 0.033 - 0.031 due 10 ppm iron

Claims (13)

1. A method for the external diagnosis of the malfunction of a device for additive additives in at least one fuel in a vehicle with internal combustion engine, characterized in that it comprises the following steps: - (a) a fuel analysis step for measuring the additive content in the fuel; (b) a comparison step between the additive content measured in the previous step and a theoretical content; (c) a step of analyzing the difference between the measured content and the theoretical content with respect to the maximum permissible deviation for the additive content. 2. Process according to claim 1, characterized in that the analysis of the fuel is carried out by a spectroscopic analysis technique. 3- A method according to claim 1 or 2, characterized in that the step (a) above is performed on a fuel sample of the vehicle tank previously removed. 20 4- Method according to claim 1 or 2, characterized in that the step (a) above is carried out online without sampling of fuel from the vehicle tank. 25 5. Process according to claim 4, characterized in that the analysis of step (a) is carried out with a spectrometer associated with an optical fiber and a probe placed in the fuel tank of the vehicle. 6. Method according to one of the preceding claims, characterized in that it comprises after step (a) above - a step (a1) additivation request to the additivation device; a step (a2) for analyzing the fuel after the additivation request; a step (a3) of calculating the additive content added in step (a1) by the difference between the fuel analysis before and after additivation; Said step (b) being a step of comparing the additive content measured after step (a3) with a theoretical content. 7- Method according to one of the preceding claims, characterized in that the additive is selected from the additives for improving the fuel distribution in the engine and / or improving the performance of the engine operation and / or improving the stability of the engine operation. 8- Process according to claim 7, characterized in that the additive is a combination of a detergent additive and a lubricating additive. 9- Method according to one of claims 1 to 6, characterized in that the additive is an additive to aid the regeneration of particulate filters. 10- Method according to claim 9, characterized in that the additive is in the form of a suspension or a colloidal dispersion of nanoparticles. 11- Process according to claim 9 or 10, characterized in that the additive is based on iron and / or cerium. 12- Method according to one of the preceding claims, characterized in that the additive is a combination of a detergent additive and an additive type FBC. 13- Method according to one of the preceding claims, characterized in that it is implemented in a vehicle assembly plant, in a concession or in a repair shop.