KR20140024324A - Method and device for calibrating a fuel metering system of a motor vehicle - Google Patents

Abstract

The present invention relates in particular to a calibration method for calibrating a fuel control system of an internal combustion engine of a motor vehicle, in which the first injector is controlled by a first test injection with a first control period and the second injector is a second injector. Controlled by a second test injection with a control period, the resulting total excitation is detected as an overlap between the first excitation of the first injector and the second excitation of the second injector, from which the first excitation of the first injector The total vibration on which the excitation and the second excitation of the second injector are reconstructed is determined, and on the basis of each excitation as the respective quantitative signal for each injector, zero quantitative correction is performed regardless of the other injector. For each injector, each minimum control period is determined. In addition, a corresponding correction device is provided.

Description

TECHNICAL AND METHOD AND DEVICE OF CALIBRATION OF FUEL CONTROL SYSTEM

The present invention relates in particular to a calibration method and apparatus for calibrating a fuel control system of an internal combustion engine of a motor vehicle.

In today's fuel injection systems of the type related to this, for example as in common rail diesel injection systems, partial injection with a relatively small amount of fuel at the same time before or after the corresponding main injection, for the purpose of improving mixer formation. Partial injection is performed. In this case, the main injection is usually calculated based on the torque requirements of the corresponding driver. The injection amount of the partial injections should be as small as possible to avoid exhaust gas shortcomings. On the other hand, the injection amount must be sufficient to ensure that the minimum quantity required for the corresponding combustion process is always set, under conditions where all tolerance sources are considered. Improved mixer formation of this type enables the reduction of emissions and the reduction of combustion noise.

In the case of the partial injections, a small fuel amount requires precise control of each injection amount. For example, in the injection components provided, namely common rail injection systems, the partial injection is completely omitted because the injector has not yet injected due to the usual tolerance when based on the trigger signal, which has a significant effect on the operation of the internal combustion engine. This, for example, results in increased noise generation during combustion. The practical co-dimensionality of the quantitative precision of the preliminary injection is the so-called drift of each injector.

In the case of the common rail diesel injection systems, by means of a high pressure accumulator, so-called "rail", pressure generation and injection are separated from each other, and injection pressure is generated irrespective of engine speed and injection quantity and can be used for injection in the high pressure accumulator. Will be. In this case, each injection time point and each injection amount is calculated in the electronic engine control device and added to corresponding injectors of each cylinder of the internal combustion engine through remotely controlled valves. In this case, it should be ensured that the partial injections are always realized with the highest possible precision.

The manufacturing tolerances that occur when manufacturing the injectors of the corresponding fuel control system lead to differences in the operating characteristics of the individual injectors, which often occur over the service life of the respective injectors or fuel control system, Even during the service life. In addition, the injectors of the fuel control system typically have different quantitative property maps, that is, different dependencies between injection volume, rail pressure and control period. As a result, different injectors fill the associated combustion chamber with different amounts of fuel even under very precise control.

The adjustment of the minimum quantitation is based on the so-called zero quantification correction. The zero quantitative correction is described, for example, in German publication DE 199 45 618 A1. In this case, the individual injectors are controlled in the so-called trailing throttle state of each internal combustion engine, and the control period is controlled until the change of the quantitative replenishment signal (reduced quantitative signal) at the minimum control period condition is set. For example, it gradually increases until a measurable torque increase is set in the internal combustion engine, which becomes a reference for identifying that the injection has started. The control period provided then corresponds to the operating state in which the injection for the relevant internal combustion engine, that is to say for the cylinder of the internal combustion engine, is directly applied. The treatment method is correspondingly carried out in connection with every injector or cylinder of the internal combustion engine. The control periods obtained in this case are stored in a so-called control characteristic map applied in the range of zero quantitative correction in subsequent control of the injectors, and the current values between the controllers are converted into correction values for the amount of fuel to be supplied, respectively.

Furthermore, from DE 10 2008 002 482 A1 a calibration method and apparatus for calibrating a fuel control system of an internal combustion engine are known, in which case one or more injectors are controlled by a first test injection using a first test injection amount and occur at this time. The first quantitative signal to be detected is detected. In this case, a first minimum control period is determined, and in addition, the one or more injectors are controlled by one or more second test injections using a second injection amount different from the first injection amount, and at least a second quantitative signal generated at this time is detected, and At least a second minimum control period is determined for at least the second injection amount. Then, the regression calculation is performed based on the first quantitative signal and the at least second quantitative signal as well as the first minimum control period and the at least second minimum control period. By the method introduced in the German publication, the learning method at zero quantification correction can be improved by reducing the time required for learning the correction value.

In the zero quantitative correction already mentioned, test injections with varying control periods are carried out on a cylinder or injector assigned to it in the trailing throttle state. For each control period, a relevant quantitative supplemental signal is calculated which can be obtained, for example, through the processing of the measured velocity signal. In this regard, the control period varies until a preset set value of the quantitative signal is reached. In a subsequent step, the control period learning value is calculated and stored non-volatile. In this case, the method is applied separately for each injector at a plurality of rail pressure stages.

Thus, the calibration of the individual injectors at the individual rail pressure stages is done sequentially.

Accordingly, an object of the present invention is to facilitate the determination of the above-described learning values.

Each of the above problems is solved by a correction method according to claim 1 and a corresponding correction device according to claim 8. Preferred embodiments are made in the respective dependent claims.

According to the calibration method according to the invention, the first injector is controlled by the first test injection and the first control period and the second test injection and the second control period is used, in particular for the correction of the fuel control system of the internal combustion engine of the automobile. The point of controlling two injectors and detecting the resulting overall excitation as a superposition of the first excitation of the first injector and the second excitation of the second injector is provided. Then, from the total excitation, the overall vibration on which the first excitation of the first injector and the second excitation of the second injector are reconstructed is determined. And based on each excitation as each quantitative signal for each injector, zero quantitative correction is performed irrespective of the other injector, so that each minimum control period is determined for each injector.

In this case, the determination of the learning values is made as in the case of normal zero quantitative correction in the trailing throttle state. However, the proposed method is executed independently and in parallel on each of the two injectors in terms of the learning process. From each test injection of both injectors, excitation of the power train occurs. The excitations overlap in the power train as they occur in parallel or approximately simultaneously. From this the corresponding speed signal evaluation determines the overall vibration with absolute value and phase. From this, the excitation of each individual injector is then reconstructed according to the principle of vector addition. Then, on the basis of the reconstructed quantitative signal for each injector, the calibration for each injector is made independently, as in the aforementioned "normal" zero quantitative calibration.

An advantage of the proposed correction method is the possibility of doubling the correction speed without having to suffer the deterioration in the signal-to-noise ratio.

According to one embodiment of the proposed correction method, the first test injection for the first injector and the second test injection for the second injector are executed at about the same time in the trailing throttle state.

In this case, according to a possible embodiment of the proposed correction method, the first injector or the first cylinder assigned to the injector and the second injector or the second cylinder assigned to the injector are orthogonal to each other.

In an alternative manner, the first injector and the second injector, or the respective cylinders, may be placed out of phase with each other or may be positioned to take a mutual angle τ according to a further embodiment, where τ is 90 °. The angle is not equal to a multiple of.

Further, each of the determined excitations may be input to each control period characteristic map and stored in the control period characteristic map as respective quantitative signals for each injector.

In the execution of the calibration method according to the invention, in the trailing throttle state, two injectors are pressed simultaneously with their respective test injections. Each of the test injections causes excitation of the vibratory structural members of the power train. The overlap resulting from the two excited vibrations can be measured by the speed sensor. Then, according to the correction method according to the invention, the amplitudes of the individual signals belonging to the respective injectors from the superimposed signal are reconstructed.

The invention also relates, in particular, to a correction device for correcting a fuel control system of an internal combustion engine of a motor vehicle. The calibration device comprises control means for controlling the first injector with the first test injection with the first control period and the second injector with the second test injection with the second control period. In addition, sensor means are also provided which are configured to detect the resulting total excitation as a superposition of the first excitation of the first injector and the second excitation of the second injector and to determine the total vibration according to the result of the total excitation. The proposed correction apparatus also includes calculation means configured to reconstruct the first excitation of the first injector and the second excitation of the second injector from the total vibration. In addition, by means of the calculation means provided, zero quantitative correction can be carried out, independent of the other injector, on the basis of each excitation as a respective quantitative signal for each injector, whereby for each injector Each minimum control period is determined.

The proposed compensator is particularly applicable to common rail diesel injection systems.

Further advantages and embodiments of the present invention are presented from the description and the accompanying drawings.

Obviously, the features mentioned above and again mentioned below can be used independently or in combination with each other as well as with each specified combination feature, without departing from the scope of the invention.

1 shows, in the example of a four-cylinder system, superimposition of amplitude signals of two orthogonal injectors or cylinders, and with each individual amplitude signals of two separate injectors, carried out according to one embodiment of a correction method according to the invention. It is a graph showing the separation of the overlap to be separated.
Fig. 2 is a coordinate graph showing a control period characteristic map of a second injector parallel-corrected with the first injector according to a further embodiment of the correction method according to the present invention, under the condition that the control period of the first injector is regarded as a parameter. to be.
3 is a coordinate graph showing a control period characteristic map of a first injector parallel-corrected with a second injector according to a further embodiment of a correction method according to the present invention, under conditions in which the control period of the second injector is regarded as a parameter; to be.
4 is a graph showing the superposition of two amplitude signals of two injectors placed so as to take an angle τ not equal to a multiple of 90 ° to each other.
5 is a schematic block diagram showing an embodiment of a correction apparatus according to the present invention.

1 shows, as part of one embodiment of the calibration method according to the invention, the excitation of two injectors simultaneously pressed into the respective test jets from the measured excitation of the vibrating structural members of the power train, especially inside the internal combustion engine of the motor vehicle. Reconstruction is shown. In this case, the measured excitation or vibration occurs as a superposition of the vibrations excited through each of the two individual injectors which are pressed into the respective test injections.

In this case, hereinafter, in the example of the four-cylinder system, it is assumed that two injectors, or correspondingly assigned cylinders, pressurized with respective test injections, lie at right angles to each other. Thus, the first injector or associated cylinder 1 is represented by the ordinate, while the second injector or cylinder 2 is shown by the abscissa. The vibration to be measured is then first shown by the phase α corresponding to the amplitude A12. This can be done, for example, as a Fourier transform of the corresponding speed signal. Respective phases of pure excitation or vibration on the first cylinder 1 or the second cylinder 2 are known from the prior art and, as already mentioned above, are used as axes in the coordinate system shown here. Then, the measured signal with amplitude A12 and phase α is projected on two axes according to trigonometric standards. This is shown in the following formula.

In the above formula,

A12 represents the amplitude of the total vibration, ie the overlap of the two vibrations caused through the respective injectors, A1 represents the reconstructed amplitude of the cylinder 1 and A2 represents the reconstructed amplitude of the cylinder 2. α is obtained from the phase or phase displacement of the excitation measured with respect to the phase of the cylinder 2 or cylinder 1.

The two individual excitations of the injectors 1 and 2 are thereby separated in a simple manner, resulting in a total excitation.

Then, for each of the two injectors, namely the first injector 1 and the second injector 2, a search algorithm according to the prior art is executed, and the control period of each injector is reached when the preset target amount is reached. Is corrected until, and then the aforementioned learning values are determined according to the prior art.

In Fig. 2, test results obtained after the execution of the correction method according to the present invention in a vehicle equipped with a four-cylinder engine are reproduced. In this case, the acquired control period characteristic map of the second injector 2 was determined three times. In this case, each control period of the first injector 1 was used as a parameter and the control periods were 140 ms, 180 ms and 220 ms, respectively. In this regard, the three determined control period characteristic curves 10, 20, 30 may generate respective predetermined quantitative signals S2 of the second injector 1 over the control period T measured in units of μs. It is shown in the graph displayed. In this case, the control period characteristic map 10 shows the control period characteristic map of the second injector 2 under the condition that the control period of the first injector is 140 ms. The control period characteristic map 20 is recorded under the condition that the control period of the first injector is 180 ms, and the control period characteristic map 30 is recorded when the control period of the first injector is 220 ms. will be. In this case, the three determined control period characteristic maps of the second injector 2 exactly overlap each other within the range of the measurement accuracy of the speed evaluation method used.

In Fig. 3 a corresponding graph of the corresponding control period characteristic maps of the first injector 1 is shown, where the injector 1 and the injector 2 seem to differ from each other in comparison to FIG. Function. In the graph shown here, each of the predetermined quantitative signals S1 of the first injector 1 is displayed over the control period T measured in units of ㎲. In this case, the control period of the second injector 2 was used as a parameter, it was 140 ms for the control period characteristic map 10 ', 180 ms for the control period characteristic map 20', and the control period characteristic map. It was 220 Hz for (30 '). Here too, the three control period characteristic maps determined for the injector 1 overlap each other precisely within the measurement accuracy range of the speed evaluation method.

Two injectors or cylinders that are placed out of phase can also be excited in such a manner as to be substituted for the above scenario where two orthogonal injectors 1 and 2 or corresponding cylinders are pressurized with respective test injections. Then, the two vibrations are extinguished correctly if the injection amounts for the respective injectors are the same. This can be used, for example, to correct two injectors accurately with each other when the absolute value of each injection to be corrected is not important.

On the other hand, in Fig. 4, the reconstruction, which is performed according to the correction method according to the present invention, is a reconstruction of vibrations excited through the first and second injectors, respectively, from the total vibrations generated through the two vibrations. . In this case, the injectors 1 and 2 take an angle τ which is not equal to a multiple of 90 °. Corresponding to FIG. 1, this arrangement is likewise shown in the coordinate system, in which the second cylinder 2 or injector 2 is indicated on the horizontal axis and the first cylinder 1 or injector 1 with respect to the horizontal axis. It is indicated on the axis rotated by τ. The coordinate axes of the coordinate system thus take an angle τ. The measured signal is again converted to a scheme with amplitude and phase and displayed correspondingly in the coordinate system. In this case, the amplitude A12 is represented by the angle α with respect to the injector 2. The reconstruction of the individual amplitudes A1 or A2 is here through the application of the law of sines, similar to the reconstruction of FIG. 1. Thus, the following generalized evaluation relations are obtained.

In FIG. 5 an embodiment of a calibration device according to the invention for controlling a fuel conditioning system is shown in a simplified block diagram. In FIG. 5, the internal combustion engine 10 by which the fuel control unit 30 adjusts a predetermined amount of fuel at a predetermined time point is shown. In this case, the sensor means detect the measurements 15 characterizing the operating state of the internal combustion engine 10 and correspondingly transmit the measurements to the control device 20 of the various sensors 40. Form, in particular in the form of a speed sensor. In addition, the control device 20 is also supplied with output signals 25 of additional provided sensors 45 for detecting variables characterizing the state and / or environmental conditions of the fuel regulation unit 30. The variable 25 is for example an actual driver request. The additional variables 25 may be for example the pressure and temperature of the ambient air. The control device 20 calculates control pulses 35 which are used to cause the fuel regulation unit 30 to be pressurized based on the measured values 15 and the additional variables 25.

The internal combustion engine is preferably a direct injection internal combustion engine and / or a self-ignition internal combustion engine.

The fuel control unit 30 may be formed in various ways. The fuel control unit can be formed, for example, as a common rail injection system already mentioned and described above. In this type of system, the high pressure pump compresses the fuel in the accumulator. The fuel then arrives in respective combustion chambers of the internal combustion engine via injectors from the accumulator. The duration and / or start of fuel injection is controlled by the injectors. In this case, the injectors preferably comprise respective solenoid valves or piezo actuators.

Each cylinder is provided with an electrically operated valve. In the following solenoid valves and / or piezoelectric actuators controlling fuel regulation are referred to as electrically operated valves.

The electrically operated valve is arranged such that the amount of fuel to be injected is determined through the opening period of the valve or through its closing period.

On the other hand, for the correction of the fuel regulation system, the control device 20 controls the first injector with the first test injection having the first control period using the control pulse 35_1 according to the present invention and the control pulse 35_2. Control means (50) for controlling the second injector with a second test injection having a second control period. In addition, the sensors 40, in particular the speed sensor provided, detect the resulting total excitation as a superposition of the first excitation of the first injector and the second excitation of the second injector and the total vibration according to the result of this total excitation. Is configured to determine. The control device 20 also reconstructs the first excitation of the first injector and the second excitation of the second injector from the total vibration, and based on each excitation as the respective quantitative signal for each injector, Regardless of the injector, it also includes calculation means 55 configured to perform zero quantitative calibration. This determines the respective minimum control period for each injector.

Claims (9)

In particular, a calibration method for calibrating a fuel control system of an internal combustion engine of an automobile, wherein the first injector is controlled by a first test injection having a first control period and the second injector is controlled by a second test injection path having a second control period. The resulting total excitation is detected as an overlap between the first excitation of the first injector and the second excitation of the second injector, from which the first excitation of the first injector and the second excitation of the second injector The total vibration on which the is reconstructed is determined, and based on each excitation as a respective quantitative signal for each injector, zero quantitative correction is performed, independent of the other injector, whereby for each injector A method of calibrating a fuel control system of an internal combustion engine, wherein each minimum control period is determined. The internal combustion of claim 1, wherein a total vibration having any absolute value and phase is determined and the first excitation of the first injector and the second excitation of the second injector are reconstructed through application of a vector addition from the total vibration. How to calibrate the engine's fuel control system. The method of claim 1 or 2, wherein the first test injection for the first injector and the second test injection for the second injector are executed at about the same time in the trailing throttle state. 4. The method of claim 1, wherein the first and second injectors are orthogonal to one another. 5. 4. The method of claim 1, wherein the first and second injectors are in antiphase with each other. 5. The method of claim 1, wherein the first and second injectors are mutually exclusive.

A method of correcting a fuel control system of an internal combustion engine, wherein the internal combustion engine is positioned to take an angle τ of the phosphorus condition. The internal combustion engine of claim 1, wherein each excitation determined as a respective quantitative signal for each injector is input to a respective control period characteristic map and stored in the control period characteristic map. How to calibrate fuel control system. In particular, a calibration device for calibrating a fuel control system of an internal combustion engine of an automobile, the first injector having a first control period for controlling the first injector and the second injector with a second control period for controlling the second injector Control means for detecting and sensor means for detecting the total excitation as a superposition of the first excitation of the first injector and the second excitation of the second injector and determining the total vibration of the resulting total excitation; Reconstruct the first excitation of the first injector and the second excitation of the second injector from the total vibration, and based on each excitation as the respective quantitative signal for each injector, perform zero quantitative correction irrespective of the other injector Thereby comprising calculation means configured for each minimum control period to be determined for each injector. 9. The apparatus for compensating a fuel control system of an internal combustion engine according to claim 8, in particular for use in a common rail injection system.

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