Fuel dispensing method

Abstract

Method for determining a characteristic of the fuel to be applied to a nozzle of an internal combustion engine, said internal combustion engine comprising a fuel tank, at least one nozzle and a characteristic measuring sensor inserted in a conduit connecting the fuel tank to said at least one nozzle, said method being characterized in that: - data of the characteristic of the fuel are collected over a first period of time by means of the measuring sensor, the average of the collected data is determined and stored in a matrix, it is associated to a volume counter having a given initial value, - for each subsequent period of time, data of the characteristic of the fuel and data of the volume of fuel injected during this period of time are collected, the volume of fuel injected is subtracted from each volume counter associated to each average of the matrix, the average of the collected data is determined, if this average differs from the last stored average by a positive or negative predetermined coefficient, said average is stored in the matrix and said average is associated to a volume counter having a given initial value, - the characteristic to be applied to the nozzle is the last average of the volume counters stored in the matrix which is less than or equal to zero.

Description

Technical Field

[0001] The technical field of this invention is an apparatus and method for controlling the fuel supply of an internal combustion engine. Background Technology

[0002] Since the advent of internal combustion engines capable of operating on fuels with variable characteristics, a highly accurate understanding of the actual taux (characteristics) of the fuel injected into the engine's combustion chamber has been essential. In fact, the taux of fuel characteristics (such as ethanol) allows for the determination of the amount of fuel to be injected to achieve complete combustion of the fuel / air mixture, thereby optimizing engine performance. Conversely, incomplete combustion negatively impacts engine performance and durability, consumes fuel, and pollutes the environment.

[0003] This type of engine requires sensors to measure various characteristics of the fuel. However, due to its inherent characteristics, such sensors can only be placed at locations with lower fuel pressures, namely between the fuel tank and the high-pressure pump upstream of the fuel injector. There is thus a delay between the characteristic content measured by the sensor and the actual characteristic content injected into the engine. This delay must be taken into account to avoid interrupting engine operation during fuel transitions (e.g., during fuel changes).

[0004] After, for example, the fuel tank is filled and the fuel in the tank has a new ethanol content, there will be a transition volume of new fuel. This volume lies between the fuel tank as measured by the ethanol content sensor and the injector. The ethanol content in the injector will change from the old content to the new content. During this transition period, it is necessary to know the ethanol content as accurately as possible to optimize engine operation.

[0005] A method is described in FR1858049, belonging to this applicant. This method includes taking fuel consumption into account when reconstructing the ethanol content at the nozzle based on ethanol content measured by a sensor. The method also takes into account the volume difference between the area around the sensor and the area around the nozzle, which affects the fuel transition rate. Finally, this method enables the detection of fuel transition based on measurements of ethanol content.

[0006] To account for delays during ethanol content transitions, this method continuously stores the data acquired by the ethanol content sensor. The ethanol content data is stored in a matrix, with a delay in recovery based on fuel consumption. Therefore, the size of the matrix used needs to be related to the distance between the sensor and the nozzle. However, using such a matrix requires significant storage resources, and the further the sensor is from the nozzle, the more storage resources are needed. Furthermore, because measurement history needs to be preserved, the matrix needs to be stored in non-volatile memory. This storage in non-volatile memory is particularly recommended when the ethanol content changes and the computer loses power. This situation may occur when a driver has just filled up the tank, moved the vehicle, and then parked it shortly afterward.

[0007] Needless to say, the above method also makes it possible to determine the content of any products contained in the fuel that the nozzle actually senses, provided that a corresponding measuring sensor is installed. Measuring sensors now exist that can measure various characteristics of the fuel, which further increases the amount of data that can be stored, thus increasing storage resources for components such as engine control units.

[0008] The amount of fuel characteristic data stored to determine the characteristics of the fuel that will actually be injected into the nozzle needs to be reduced. Summary of the Invention

[0009] Therefore, the present invention relates to a method for determining the characteristics of fuel to be applied to an nozzle of an internal combustion engine, the internal combustion engine including a fuel tank, at least one nozzle, and a measuring sensor for measuring the characteristics, the measuring sensor being inserted in a conduit connecting the fuel tank and the at least one nozzle, the method being characterized in that:

[0010] - Using a measuring sensor, data on the characteristics of the fuel are collected over a first time period. The average value of the collected data is determined and compared to a reference value. If the average value differs from the reference value by a predetermined positive or negative coefficient, the average value of the collected data is stored in a matrix. Alternatively, if the matrix does not include the reference value, the average value of the collected data becomes the reference value.

[0011] - Whenever a new reference value for the average of the collected data is obtained, it is correlated with a volume counter, the initial value of which corresponds to the volume of the conduit located between the measuring sensor and the at least one nozzle.

[0012] - For each subsequent time period, collect the data on the characteristics of the fuel and the data on the fuel volume injected during each time period, and subtract the fuel volume injected for each elapsed time period from each volume counter associated with each average of the matrix.

[0013] - The fuel to be applied to the nozzle is characterized by the earliest average value of the volume counters stored in the matrix that are less than or equal to zero.

[0014] According to one embodiment of the invention, the predetermined coefficient corresponds to the error tolerance of the characteristics of the fuel to be applied to the nozzle that are acceptable to the nozzle.

[0015] According to another embodiment of the invention, the predetermined coefficient K is between 2% and 5%.

[0016] According to another embodiment of the present invention, when the volume counter associated with the average value is less than or equal to zero, the volume counter and the average value are removed from the matrix.

[0017] According to another embodiment of the invention, the characteristics of the fuel to be applied to the nozzle of an internal combustion engine correspond to the ethanol content of the fuel.

[0018] According to another embodiment of the invention, the characteristics of the fuel correspond to characteristics selected from the group consisting of: fuel density, fuel PCI (lower heat of combustion), fuel octane number, fuel cetane number, and fuel ester content.

[0019] According to another embodiment of the invention, in the previous feature P applied to the nozzle Rj Estimate the characteristics of the fuel to be applied to the nozzle by comparing them with the characteristics of the next fuel to be applied to the nozzle.

[0020] Advantageously, the estimation includes applying an affine law through which the features of the previous application are passed, the slope of which is equal to the gradient between the features of the next application and the features of the previous application, and the application of the affine law continues until the next feature to be applied is received, or the estimation is limited to the next feature to be applied.

[0021] The present invention also relates to an engine control unit for implementing the method according to the present invention in an internal combustion engine.

[0022] One advantage of this invention is that it reduces the amount of data stored in the memory of, for example, the engine control unit.

[0023] Another advantage of the present invention is the ability to determine multiple characteristics of the fuel to be applied to the nozzle.

[0024] Another advantage is the reduction in costs associated with implementing methods for determining the characteristics of the fuel to be applied to the nozzle. Attached Figure Description

[0025] Other features, advantages, and details of the invention will be better understood by reading the following further description in conjunction with the accompanying drawings, in which:

[0026] Figure 1 A schematic diagram of an internal combustion engine is shown.

[0027] Figure 2 A graph illustrating the changes in fuel characteristics as measured by a measuring sensor is shown.

[0028] Figure 3 A flowchart illustrating the steps of a method according to an embodiment of the present invention is shown, and

[0029] Figure 4 Another flowchart illustrating the steps of a method according to an embodiment of the present invention is shown.

[0030] Figure 5 An example of estimating the ethanol content of the injection is shown in a graph. Detailed Implementation

[0031] As described above, the present invention relates to a method for determining the characteristics of fuel to be applied to an nozzle of an internal combustion engine.

[0032] Within the scope of this invention, "fuel characteristics" refers to the inherent characteristics of the fuel used for engine operation. These characteristics relate to the type of fuel the engine is permitted to use. In particular, small-cylinder-displacement turbocharged direct-injection gasoline engines with highly optimized efficiency can be cited. For this type of engine, very precise knowledge of the ethanol content is required.

[0033] Within the scope of this invention, "characteristics of fuel" means any characteristic that characterizes the fuel used. Fuel characteristics may in particular correspond to the fuel's ethanol content, density, PCI, octane number, cetane number, or ester content.

[0034] Figure 1 An internal combustion engine that can be used to implement the method according to the invention is shown. The engine includes a fuel tank 1 connected to a nozzle 4 via a conduit 5, a feature measurement sensor 3 located at the conduit 5, and an engine control unit 2. (Using V) TOT This represents the volume of the conduit 5 located between the measuring sensor 3 and the nozzle 4.

[0035] The measuring sensor 3 collects data on the characteristics of the fuel passing through the conduit 5 at regular time intervals.

[0036] Nozzle 4 enables the injection of the desired amount of fuel into the combustion chamber.

[0037] The engine control unit 2 enables the storage, processing, and retransmission of data collected by the measuring sensors to the nozzle 4. The engine control unit 2 specifically includes a data storage device, a data processing device, and a nozzle 4 control device. The engine control unit 2 enables the implementation of the method according to the invention.

[0038] Therefore, the method according to the invention enables the determination of the characteristics of the fuel to be injected downstream of the measuring sensor while taking fuel consumption into account.

[0039] Figure 2A graph illustrating the changes in fuel characteristics as measured by a measuring sensor is shown.

[0040] In five time periods T x-1 T x T x+1 T x+2 and T x+3 The above example illustrates the characteristic changes. Time periods T x-1 T x T x+1 T x+2 and T x+3 The duration of each time interval can vary and is related to the fuel characteristics being measured and the changes in those characteristics. Therefore, the duration of a time interval is typically between 1 second and 20 seconds, preferably 10 seconds.

[0041] Initially, by means of a measuring sensor, in the first time period T x-1 Data on the characteristics of the collected fuel P x-1 Data P x-1 In time period T x-1 Data was collected at regular time intervals during the period. Data P x-1 The collection interval is greater than the duration T x-1 Short. For example, for a duration T equal to 10 seconds. x-1 Data P is collected every 100ms.

[0042] The collected data P x-1 This allows us to determine the duration T. x-1 Data P collected during the period x-1 Average PM x-1 This is how it works in time period T. x-1 The average PM was determined at the end. x-1 .

[0043] Therefore, the average PM x-1 Reference value PM of the average of the collected data included in the matrix CURi-1 Compare them. If the average PM x-1 Reference value PM compared to the average of the collected data CURi-1 The difference is determined by a predetermined coefficient K, or if the matrix does not include reference values, then data P will be collected. x-1 Average PM x-1 Stored in a matrix and used as a reference value PM CURi .

[0044] Whenever a new reference value PM for the average of the collected data is obtained. CURi At that time, it is associated with the volume counter CV. i The volume counter CV i initial value VTOT Corresponding to the volume of the conduit located between the measuring sensor 3 and the at least one nozzle 4.

[0045] Volume counter CV i The initial value is equal to V. TOT In fact, the average PM value used to determine the characteristics of the fuel at the measurement sensor is... x-1 Therefore, PM with average characteristics x-1 The fuel needs to complete the measurement of the equivalent volume V between the sensor and the nozzle. TOT Only then can it reach the nozzle.

[0046] This results in a matrix containing elements with an initial value of V. TOT Volume counter CV i Related single data PM x-1 This makes it possible to significantly reduce the time interval T in a single time period. x-1 The amount of data stored internally. If we consider a time period T... x-1 The process lasts for 10 seconds, and data is collected every 100ms. x-1 Then the amount of data stored will be reduced to one percent. If the average feature PM x-1 Only every 50 time periods T x-1 With PM CURi If there is a discrepancy, the amount of data stored will be reduced to one five-thousandth.

[0047] according to Figure 2 The embodiment of the method according to the present invention shown has a time period T. x-1 Then comes the time period T. x Time period T x Then comes the time period T. x+1 Time period T x+1 Then comes the time period T. x+2 Time period T x+2 Then comes the time period T. x+3 .

[0048] Therefore, the method according to the invention includes a continuous time period T. x T x+1 T x+2 And so on. For each subsequent time period T... x T x+1 T x+2 Waiting in the previous time period T x-1 T x T x+1 Start at the end. For each subsequent time interval T... x T x+1 T x+2 Wait, during time period T x Tx+1 T x+2 Data on fuel characteristics collected during the same period P x P x+1 P x+2 Equal injection fuel volume VI x VI x+1 VI x+2 wait.

[0049] The predetermined coefficient K corresponds to the acceptable error tolerance of the fuel characteristics to be applied to the nozzle. The acceptable tolerance means that as long as the characteristics of the fuel applied to the nozzle show an error not exceeding the predetermined coefficient K, the engine operation remains optimal. The coefficient K is specifically based on the measured fuel characteristics. The coefficient K is typically between 2% and 5%, preferably 3%.

[0050] Thus, in each time period T x At the end, obtain the reference value PM. CURi and the volume of fuel injected VI x Injected fuel volume VI x Make the reference value PM in the matrix CURi Associated volume counter CV x The value decreases. The fuel characteristic P to be applied to the nozzle... Rj It is a volume counter CV stored in a matrix. i The earliest reference value for less than or equal to zero PM CURi In fact, each volume counter CV i They all have an initial value V TOT And in each time period T x At the end, reduce the volume of the sprayed material (VI) during that time period. x Therefore, each counter CV i Decrease, when it is less than or equal to zero, which means that the associated average PM x The nozzle has been reached. The actual features seen at the nozzle and therefore the features P applied to the nozzle. Ri It is the associated volume counter CV stored in the matrix. i The earliest reference value for less than or equal to zero PM CURi According to one embodiment of the present invention, the volume counter CV is removed from the matrix. i Reference value PM less than or equal to zero CURi .

[0051] The value P Rj This will be applied to the nozzle until the new counter CV is reached. i+1 It becomes less than or equal to zero. The reference value PM associated with this counter. CURi The new feature P to be applied to the nozzle Rj+1Although the fuel characteristics actually observed by the nozzle are at value P Rj With P Ri+1 The error varies between these values, but because the error is less than or equal to the predetermined coefficient K, it remains at a minimum.

[0052] To overcome this deficiency, one embodiment of the method according to the invention enables the estimation of the characteristics of the fuel to be applied to the nozzle in two values ​​P. Rj The changes between them. Thus, in the previous feature P applied to the nozzle... Rj With the characteristic P of the next fuel to be applied to the nozzle Rj+1 The estimation between the parameters is to be applied to the nozzle feature P. R This estimation includes, for example, the application of features P from a previous application. Rj The affine law has been passed, and the slope of this affine law is equal to the feature P of the previous application. Rj-1 Feature P of the previous application Rj The gradient between them is used to apply the affine law until the next feature P to be applied is received. Rj+1 Or estimate one of the features P to be applied. Rj+1 Limited to.

[0053] This estimation, as a function of time, is achieved by applying, for example, affine or linear laws. Thus, based on the gradient of the previous change, the characteristic P of the fuel applied to the nozzle is... Rj It will saturate due to the value of the predetermined coefficient K until a new feature P to be applied is received. Rj+1 Alternatively, if a new feature P to be applied is received before saturation. Rj+1 If so, apply it immediately.

[0054] Therefore, the gradient is applied until the next feature P to be applied is received. Rj+1 Or until the gradient value of the application is similar to the feature P of the previous application. Rj The difference is a positive or negative coefficient K.

[0055] The instantaneous ethanol content was estimated based on the previously calculated slope. (From the volume counter CV) i From the instant the value reaches zero or a negative value, the estimated instantaneous ethanol content is equal to the value P. Rj From this moment on, based on the feature P of the previous application... Rj The estimated ethanol content of the instantaneous injection was calculated using an affine law whose slope equals the previously calculated gradient. Therefore, the affine law is applied:

[0056] -until the next volume counter CV i+1 The value reaches zero or is negative. In this case, the estimated instantaneous ethanol content is then corrected and adjusted to the value PM. CURi+1;or

[0057] - Until the estimated value of the ethanol content in the immediate spray reaches the value of PM CURi+1 In this case, the estimated ethanol content of the instantaneous injection is frozen at a value of PM. CURi+1 Until the next volume counter CV i+1 It reaches a negative value. This is how it works for each time period T. x Repeat the method according to the invention.

[0058] Figure 5 The above process is illustrated: the horizontal axis represents time, and the vertical axis represents the estimated ethanol concentration at the nozzle. Between two restorations a, b, c, and d, the instantaneous ethanol content is estimated based on the slope determined from the just received sample and the previous sample. This ethanol content will be saturated with the value of the next sample. Figure 5 In the example, when sample b is received, the gradient is calculated using the measurements of samples a and b, and this gradient is referenced until sample c is received. Figure 5 There is: a = P Rj-1 b = P Rj c = P Rj+1 (To be received), d = P Rj+2 (Pending receipt)

[0059] refer to Figure 2 The example shown illustrates the evolution of a matrix.

[0060] In time period T x-1 At the end, the matrix consists of a single value PM x-1 The composition, and its related initial value is V TOT Volume counter CV i-1 Average PM x-1 Therefore, the reference value is PM. CURi-1 Because it is the previous value stored in the matrix.

[0061] In time period T x At the end, the average PM was obtained. x and during duration T x The value of the volume of the injection during the period VI x The average PM x Compared with reference value PM CURi-1 (PM here) x-1 They are compared to determine if they differ by a predetermined coefficient K. According to this example, the value PM... CURi-1 With PM x Since there is no predetermined positive or negative coefficient K, the average value PM is not included. x Included in the matrix. Volume counter CV i-1 Reduce VIx The value of . Thus, in the time period T x At the end, the matrix is ​​composed of the reference value PM CURi-1 Composition, and related to it is the value V TOT -VI x Volume counter CV i-1 .

[0062] In time period T x+1 At the end, the average PM was obtained. x+1 and during duration T x+1 The value of the volume of the spray during the period VI x+1 The average PM x+1 Compared with reference value PM CURi-1 (PM here) x-1 They are compared to determine if they differ by a predetermined coefficient K. According to this example, the value PM... CURi-1 With PM x+1 Since there is no predetermined positive or negative coefficient K, the average value PM is not included. x+1 Included in the matrix. Volume counter CV i-1 And all the previous volume counters CV i-2 All of these reduce VI x+1 The value of . Thus, in the time period T x+1 At the end, the matrix is ​​composed of the reference value PM CURi-1 Composition, reference value PM CURi-1 With volume counter CV i-1 Relatedly, the volume counter CV i-1 The value is V TOT -VI x -VI x+1 The volume counter also decreased the value VI. x+1 The previously stored value.

[0063] In time period T x+2 At the end, the average PM was obtained. x+2 and during duration T x+2 The value of the volume of the spray during the period VI x+2 The average PM x+2 Compared with reference value PM CURi-1 (PM here) x-1 They are compared to determine if they differ by a predetermined coefficient K. According to this example, the value PM... CURi-1 With PM x+2 The difference is due to a positive or negative predetermined coefficient K, therefore the average value PM x+2 Stored in a matrix and used as a reference value PM CURi Volume counter CV i-1 And all the previous volume counters CV i-2All of these reduce VI x+2 The value of . Thus, in the time period T x+2 At the end, the matrix is ​​composed of the reference value PM CURi-1 and reference value PM CURi Composition, reference value PM CURi-1 With volume counter CV i-1 Relatedly, the volume counter CV i-1 The value is V TOT -VI x -VI x+1 -VI x+2 The volume counter also decreased the value VI. x+2 The previously stored value, reference value PM CURi With an initial value of V TOT Volume counter CV i Related.

[0064] In time period T x+3 At the end, the average PM was obtained. x+3 and during duration T x+3 The value of the volume of the spray during the period VI x+3 The average PM x+3 Compared with reference value PM CURi-1 (PM here) x+2 They are compared to determine if they differ by a predetermined coefficient K. According to this example, the value PM... CURi With PM x+3 The difference is due to a positive or negative predetermined coefficient K, therefore the average value PM x+3 Stored in a matrix and used as a reference value PM CURi+1 Volume counter CV i-1 and CV i Reduce VI x+3 The value of . Thus, in the time period T x+3 At the end, the matrix is ​​composed of the reference value PM cURi-1 Reference value PM cURi and reference value PM CURi+1 Composition, reference value PM CURi-1 With value V TOT -VI x -VI x+1 -VI x+2 -VI x+3 Volume counter CV i-1 Related, reference value PM CURi With volume counter CV i Related, and reference value PM CURi+1 With an initial value of V TOT Volume counter CV i+1 Related.

[0065] Now assume that in time period T... x+3 At the end, compared with the average PM x-1 (CV i-1 The earliest associated volume counter is less than or equal to zero. Therefore, in time period T... x+3 The feature P to be applied to the nozzle at the end Rj It is a characteristic PM x-1 .

[0066] Figure 3 A flowchart illustrating the steps of a method according to an embodiment of the present invention is shown, wherein the fuel being measured is characterized by its ethanol content. The flowchart illustrates a fast computational loop, for example, performed by an integrated computer at each time period t. Figure 3 In the example shown, t equals 100 ms. The flowchart illustrated also enables the determination of the average ethanol content, its storage in a matrix, and its association with a volume counter.

[0067] In this way, the ethanol content and injected fuel volume at the measurement sensor are measured every 100 ms. For each subsequent time period T, the cumulative ethanol content and cumulative injected fuel volume are determined.

[0068] As shown in step 10, the cumulative ethanol content is equal to the sum of the ethanol content measured in each time period T. Similarly, the cumulative injected fuel volume is equal to the sum of the injected fuel volumes measured in each time period T.

[0069] When the sum of time periods t is greater than or equal to the predetermined time period T1, as shown in step 11, the average value of the ethanol content measured during time period T1 is calculated in step 12. If the average value of the ethanol content determined in time period T differs from the previous average value of the ethanol content stored in the matrix by a positive or negative coefficient K (step 13), then the average value of the ethanol content determined in time period T is stored in the matrix and becomes the previous average value of the ethanol content stored in the matrix, and is associated with the initial value V. TOT Volume counter (step 14).

[0070] The next steps enable the determination and estimation of the ethanol content to be applied to the nozzle. These steps also include... Figure 4 The slow calculation loop 15 is shown.

[0071] Figure 4 This is a flowchart illustrating the steps of a method according to an embodiment of the present invention. The flowchart shows the aforementioned slow computation loop 15, for example, executed by a computer in each time period T1. Figure 4 In the example shown, T1 = 10 s. This slow calculation loop also makes it possible to determine and estimate the ethanol content to be applied to the nozzle.

[0072] Thus, for each time period T1, the volume counter associated with each average ethanol content stored in the matrix is ​​reduced by the value of the fuel volume injected during time period T1 (step 16). When the volume counter becomes less than or equal to zero (step 17), the associated average ethanol content is then the average ethanol content to be applied to the nozzle (step 18).

[0073] Therefore, it is necessary to estimate the ethanol content to be applied to the nozzle until the next ethanol content to be applied to the nozzle is determined. This determines the new estimated slope (step 19). This slope is equal to the slope between the average value of the previous application to the nozzle and the average value of the new application to the nozzle.

Claims

1. A method for determining the characteristics of fuel to be applied to an nozzle (4) of an internal combustion engine, the internal combustion engine including a fuel tank (1), at least one nozzle (4), and a measuring sensor (3) for measuring the characteristics, the measuring sensor (3) being inserted in a conduit (5) connecting the fuel tank (1) and the at least one nozzle (4), the method being characterized in that: - Using a measuring sensor (3), data on the characteristics of the fuel are collected over a first time period. The average value of the collected data is determined and compared with a reference value. If the average value differs from the reference value of the average value of the collected data by a predetermined positive or negative coefficient, or if the matrix does not include the reference value, the average value of the collected data is stored in the matrix, and the average value of the collected data becomes the reference value. - Whenever a new reference value for the average of the collected data is obtained, it is correlated with a volume counter whose initial value corresponds to the volume of the conduit located between the measuring sensor (3) and the at least one nozzle (4). - For each subsequent time period, collect the data on the characteristics of the fuel and the data on the volume of fuel injected during each time period, and subtract the volume of fuel injected for each elapsed time period from each volume counter associated with each reference value of the matrix. - The fuel to be applied to the nozzle is characterized by the earliest reference value of the volume counter stored in the matrix that is less than or equal to zero.

2. The method according to claim 1, characterized in that, The predetermined factor corresponds to the error tolerance of the characteristics of the fuel that the nozzle is acceptable for application to the nozzle.

3. The method according to claim 1, characterized in that, The pre-booking coefficient is between 2% and 5%.

4. The method according to any one of claims 1 to 3, characterized in that, When the volume counter associated with the reference value is less than or equal to zero, the volume counter and the reference value are removed from the matrix.

5. The method according to any one of claims 1 to 3, characterized in that, The characteristics of the fuel to be applied to the nozzle (4) of an internal combustion engine correspond to the ethanol content of the fuel.

6. The method according to any one of claims 1 to 3, characterized in that, The characteristics of a fuel correspond to characteristics selected from the group consisting of: fuel density, fuel lower heat of combustion (PCI), fuel octane number, fuel cetane number, and fuel ester content.

7. The method according to any one of claims 1 to 3, characterized in that, Estimate the characteristics of the fuel to be applied to the nozzle by comparing the characteristics of the previous feature applied to the nozzle with the characteristics of the next fuel to be applied to the nozzle.

8. The method according to claim 7, characterized in that, The estimation includes applying an affine law through which the features of the previous application are passed, the slope of which is equal to the gradient between the features of the previous application and the features of the previous application, and applying the affine law until the next feature to be applied is received.

9. The method according to claim 7, characterized in that, The estimation includes applying the affine law through which the features of the previous application are passed, the slope of which is equal to the gradient between the features of the previous application and the features of the next application, and the estimation is limited to the features to be applied next.

10. An engine control unit (2) for an internal combustion engine, which is used to implement the method according to any one of claims 1 to 9.

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