KR0148796B1 - Process for metering fuel - Google Patents

Abstract

One of the two methods of determining the fuel amount is characterized by calculating the suction line pressure that can be replenished during the next intake stroke, thereby determining the amount of fuel to be injected during the next intake stroke. The second method is characterized in that the amount of air determined by the suction tube pressure is corrected by a model that takes into account the temperature effect. These two methods contribute to a better preliminary calculation of the fuel quantity, which is particularly advantageous in the case of unfixed transitions. In addition, the ignition time is preferably set by the amount of air calculated in advance.

Description

[Name of invention]

How to determine the amount of fuel supplied to the internal combustion engine

Detailed description of the invention

The present invention relates to a method for determining the amount of fuel to be supplied to an internal combustion engine during each stroke.

The method known in the art will be described later with reference to the known device shown in FIG. This apparatus comprises means (11) for determining control values, means (12) for determining non-fixed transition values, adjustment means (13), throttle flap (15), inlet valve device (16) at suction line (18). And an internal combustion engine 14 having a pressure sensor 17 and also having a lambda probe 19 in the exhaust pipe 20. Initially, the internal combustion engine 14 is considered to be in controllable operation. In this case, only the signal from the means 11 for determining the control value acts on the injection valve device 16. An operating parameter value, in particular the setting angle of the prottle flap 15 and the engine speed are provided to the means 11 for determining the control value, so that the means 11 emits an injection time signal. In addition, only the pressure signal from the suction pipe pressure sensor 17 can be supplied to the means 11 for determining the control value as an input signal. The injection time is then basically set in proportion to the measured pressure. The signal is advantageously corrected to the value read out from the characteristic group as a function of the operating parameter value in the full load range.

Simply controlling the injection time is often insufficient to achieve the desired amount of exhaust gas. This can be improved with the help of the lambda probe 19 and the adjusting means 13. For this purpose, the actual lambda value from the lambda probe 19 is compared with the desired lambda value at the comparator stage 21, so that the difference value is provided to the adjusting means 13 as a control deviation, and the adjusting means 13 The set value is determined in the form of an adjustment factor RF multiplied by the value provided by the means 11 for determining the control value in the set value logic stage 22 as a function of the control deviation. The control circuit supplements that the control values for which the desired lambda values cannot be obtained alone are corrected in such a way that they can nevertheless achieve this object.

Regardless of whether the amount of fuel to be injected is controlled or whether there is pilot control of overlapping adjustment, it should be remembered that the values determined by the control value determining means 11 are normally determined in the stop operating state. However, for example, when acceleration occurs between the first stop operation state and the second stop operation state, acceleration enhancement is required in the movement. Non-stop transition value determining means 12 may be provided to handle the non-stop state and other non-stop states according to the present embodiment. If the operating parameter value is changed due to a high time change, the non-stop transition value determining means 12 calculates a time sequence of values logically associated with the control value in the non-stop correction stage 23.

Non-stop correction can only be made through the control system or pilot control system of redundancy adjustment. For all practical applications, special problems arise in the case of the above state where a number of non-stop conditions for initializing new non-stop transition functions are satisfied in a short time sequence. As a result, overlap may occur that actually strengthens or offsets each other in an undesirable way.

In order to prevent this type of overlap, efforts have been made to continuously determine the control value through the same method, that is, no deviation occurs between the stop operating state or the non-stop operating state. This method is based on Non-stationary behavior-a new factor in engine tuning by M. Theissen, H.-St. Braun and G. Kramer in Conference Volume 1 Aachener Conference, Vehicle and Engine Technology '87, Aachen October 1987. When no specific measurement is taken, occurrence errors in the control value determination in the non-stop method are designated as update errors, phase errors and wall-film errors. The update error occurs in the usual way, i.e. when a non-stop event occurs after calculating the amount of fuel to be injected during the next stroke and so the new fuel amount calculated in this event can be calculated before the intake stroke is over, a post injection occurs. Is handled in such a way. Wall error is estimated separately as a function of various operating parameter values. Phase error is an error that arises especially from the fact that the air mass meter measures not only the air sucked in combustion, but also the air that increases the pressure in the suction pipe. This phase error is compensated by adjusting the slope of the signal coming from the air mass meter with the slope of the suction tube pressure. Therefore, the suction pipe pressure is measured, and the amount of air sucked in combustion at each stroke is determined by the suction pipe pressure.

Since the phase error is adjusted by adjusting the slope of the signal from the air mass meter to the slope of the signal from the pressure sensor in the non-stop state, this method is a standard in which the amount of air sucked in combustion is directly determined from the measured suction pressure. It is done in a similar way. However, in this method, it is known that these methods do not satisfactorily compensate for the phase error occurring in the nonlinear method.

It is an object of the present invention to provide a method for determining the amount of fuel entering the internal combustion engine during each stroke, through which phase errors can be prevented.

The invention is given by the features of claims 1 and 10. Further preferred embodiments of the method according to claim 1 are added to subclaims 2-9. The two methods are used separately from each other or jointly with each other. An additional correction method for the ignition time is added to claim 11.

The method according to claim 1 is that the amount of air sucked in combustion is not determined from the suction pipe pressure currently measured, but from the suction pipe pressure occurring during the next stroke, and the calculation of the air volume is carried out to the previously calculated suction pipe pressure. It is characterized by. This procedure allows the suction pipe pressure to change relatively sharply from stroke to stroke during a non-stop transition, i.e. in the case of the amount of fuel injected during the next stroke, an optimum control value can be obtained when the pressure of the suction pipe is precomputed. I'm using the facts.

The method according to claim 10 is characterized in that the amount of air determined by the suction tube pressure can be corrected, in particular by a value taken in accordance with temperature influences.

The amount of air drawn in during combustion does not match the amount of air that can be expected in relation to the pressure conditions. Here, it should be remembered that the pressure state actually affects the flow of air volume, not air mass. The air mass with a certain volume also varies with the temperature of the air being sucked. However, temperature conditions in internal combustion engines change during non-stop transitions. The relationship between the correction value and the operating parameter value may be set in advance. This preset relationship is utilized to correct the amount of air initially determined as the suction pipe pressure.

Several alternatives are specified for determining the suction canal pressure during subsequent strokes according to claim 1, which have their particular advantages in accordance with the various aspects.

By assuming that the suction pipe pressure changes in time according to a specific function, the following suction pipe pressure can be calculated.

In the simplest case, a linear change is assumed, but this results in a very small deviation between the calculated and measured values when the first order transition function is required for the change. There are four parameters. These parameters can be determined, for example, by measuring the suction line pressure and the stop occurrence time for three series periods including the current period, storing these values and then calculating the current value of the parameter from the four measurement results. The suction line pressure present during the next stroke can then be determined using the set transfer function. This method is characterized by the fact that it always acts at its current value, that is, without a group of features. As a result, this change in shape is particularly effective after a change in the flow cross section due to a change in the fixed angle of the throttle flap. The accuracy is highly high when not additionally generated. However, if the cross section changes continuously, the parameters of the transfer function also change continuously but this is not taken into account sufficiently. This is because already useless values are used in the calculations.

In the latter case, a more accurate process is necessarily the determination of the predominant suction tube pressure during the next stroke based solely on the current suction cross section, the current speed and the current suction tube pressure. Obtaining a new value is possible when the start of each calculation cycle is determined by the time of the transition function and the property group is used, in particular one for the final value of the transition function and one for the time constant of the transition function. The last parameter is determined by determining the current suction line pressure. This determination is made by measuring the suction pipe pressure or by using the suction pipe pressure as the current pressure, calculated as the subsequent pressure in the entire cycle in the ignition. The advantage of the first alternative is that the current suction line pressure is always at a reliable and accurate value. However, there is a drawback that a pressure sensor, that is, a relatively expensive component, is required. The advantage of the second alternative is that there is no need for a pressure sensor, but the pressure calculated from the ignition may deviate slightly from the actual pressure.

By measuring the pressure in the suction line, the numerical values in this group of properties can be adapted according to the beneficial further development. Measurement of the air mass flow allows for further applications. It is remarkably advantageous to determine the combustion time as well as the amount of fuel supplied by the amount of air calculated above.

[Brief Description of Drawings]

The invention is described in detail below by way of exemplary embodiments shown by the figures.

1 to 4 show the time-dependent view of the change in the set angle of the throttle flap, the related change in suction line pressure, the change in air volume and the wall fuel amount in relation to the associated temperature,

5 shows a preferred method flow diagram in the form of a block diagram,

6-8 show a partial method flow diagram for determining the predominantly suction tube pressure during the next period, the partial method flow is shown in a flow chart in FIG. 6 but in a block diagram in FIGS.

9 shows a flowchart for explaining an application method,

10 shows a diagram illustrating the time relationship between the intake stroke and the calculation period.

Description of a Typical Example

The following description assumes that the suction pipe has a throttle flap corresponding to the throttle flap of FIG. 10 to adjust the flow cross section of the air. Thus, the throttle flap angle is always mentioned instead of the flow cross section. If another device, for example a slide or lamellar device, is used in place of the throttle flap to adjust the cross section, the displacement movement or lamella angle must therefore replace the throttle flap angle. It is further assumed that the fuel supply is made later by the injection valve device.

However, it is also possible to use another fuel proportionately supplying device, for example a Cabreta, which is always arranged to add a certain amount of fuel to the amount of air sucked in the intake stroke. Finally, it is pointed out that it is not important whether the values calculated according to the procedure described below are used only for controlling the fuel volume or for pilot control of superposed regulation.

Preferred exemplary embodiments are now described by FIGS. 1 through 5.

In FIG. 1, the throttle flip angle α is plotted against time t. At the time point to, the throttle flap angle changes rapidly from the previous invariant value to a new invariant value corresponding to the orifice cross-section than the previous orifice.

As a result of the increased orifice cross section, the suction tube pressure rises with the change of the throttle flap angle, in particular essentially with the primary transition function, ie according to the following equation.

The change in time at the suction tube pressure ps (t) is plotted in FIG.

This makes it possible to predict what value the suction tube pressure takes at a time later than the current time point by the time interval? T (w). This time interval is likewise shown in FIG.

It should be remembered here that the suction line pressure has to be predicted for a specific crank-angle interval, not for a specific time interval in actual calculations.

For simplicity, the first predicted time interval corresponds to a permanently fixed crank-angle interval 720 °, i.e. the distance between two suction strokes for a particular fixed cylinder. The number of calculation cycles for a particular cylinder is then equal to the suction stroke of this cylinder. The particular current calculation period is later represented by the letter n.

According to FIG. 5, the suction tube pressure is calculated in the means 24 for the pressure calculation. During the current calculation period n, the predominant pressure ps (n + 1) is calculated during the next suction stroke of one particular cylinder under consideration. The calculation example is further explained below in connection with FIGS. 1 to 6.

The potential volume of air mLV (n + 1) that is likely to be inhaled on the next intake stroke is calculated from the inlet line pressure pS (n + 1) for the next stroke.

Except for the full load range, it is known that this amount is essentially proportional to the suction line pressure.

In a typical embodiment, the potential air volume mLV (n + 1) is read from the group 1 air mass characteristics 25, which are presented in particular as values of the calculated intake pipe pressure pS (n + 1), speed w and engine temperature tw.

The temporal trend of the air volume mLV (t) calculated as a function of the suction tube pS (t) is shown in FIG. In FIG. 3, the air volume mLT (t) is plotted according to the temperature variable that must be applied to the temporary air volume to find the additional air volume, in particular the volume of air actually inhaled for combustion (t). The air volume mLT (t) according to the temperature variable is calculated by the auxiliary temperature variable ΔT (t). To this end, the auxiliary variables TStat (n), h1 (n) and h2 (n) are plotted according to FIG. 5 as values of the throttle flap angle, speed and engine temperature of one root-temperature-variable calculation period n. Read at (26).

The value read is converted into a future value ΔT (n + 1) by means for the ignition calculation 27, which is multiplied by a constant kT and the provisional air volume mLV (n + 1), and thus the amount of air according to the temperature variable thus obtained. mLT (n + 1) is added to the potential air volume mLV (n + 1). It is possible to calculate the amount of fuel to be added to the amount of air to obtain a specific lambda value from the amount of air mL (n + 1) drawn from the suction pipe thus determined. According to FIG. 5, the conversion is at divider stage 28. However, the amount of fuel so calculated is the amount of fuel that will be added to the amount of inhaled air, as some fuel is also used to form a wall-film or is released from the wall if it starts deceleration instead of acceleration, as opposed to first degree. Not the same Therefore, the fuel amount calculated from the intake air amount mL (n + 1) is only a provisional fuel amount mkV (n + 1).

The temporal trend of the potential fuel amount mkV (t) is plotted in FIG. Additional fuel quantity mK to be injected for wall formation (t) is also drawn there.

The actual amount of fuel mk (t) to be injected is the sum of the amount of potential fuel and the amount of fuel required for wall formation. This summation is also shown in FIG.

Therefore, the flow of the method is generally that the pressure in the suction pipe is calculated from the throttle flap angle, the amount of air sucked in is determined as the pressure in the suction pipe, and this temporary determined value is corrected to the value according to the temperature change, The amount of fuel required to obtain a predetermined lambda value is calculated from the correction value, and the amount of fuel is corrected through a wall-film model to obtain a substantial amount of fuel to be injected for the stroke following the current stroke. Is done.

Now, an embodiment of how the calculation for pressure is performed well will be described in detail with reference to FIGS. 6-8. The operating point for the third step method described in relation to Figures 6-8 is the first order transition function according to Figure 2 and equation (1). The first-order transition function most accurately represents the action observed on an internal combustion engine after a sudden change in throttle flap angle.

The first-order transition function of equation (1) has three parameters, specifically, the final pressure pStat, the initial pressure pS (to) and the time constant kp. In the method according to FIG. 6, all three parameters are determined to be pressure measurements, whereas in the methods of FIGS. 7 and 8, two parameters are determined from a characteristic group and the third parameter can be obtained from a pressure measurement or otherwise The determination of the third parameter can be omitted by using. The jump time to is reset to zero in each calculation period, resulting in pS (to) = pS (n).

In some processes of FIG. 6, the pressure pS (n) is measured in steps s1,6 during the current calculation period.

From this newly measured value and the two values ps (n-1) and pS (n-2) measured in the previous period, three parameters of equation (1) are determined in step s2.6 and thus period n The suction pipe pressure pS (n + 1) at +1 hour is determined from equation (1). In step s3.6, the pressure value of the last cycle is determined as the pressure value of the last cycle, but the pressure value of the current cycle is determined as the pressure value of the previous cycle, so that these two values are used to calculate the amount of fuel to be injected. After execution of the additional method step, when step s1.6 again reaches the next cycle, it is valid as a past value, so that the measured pressure becomes the current pressure. The pressure calculation method then provides a pressure value for the next period, which corresponds very closely to the value measured when the throttle flap change suddenly occurs, as shown in FIG. In particular, the transition equation applies to all measurement points, ie the three parameters remain unchanged. However, if the throttle flap angle changes between measurement points, the parameters also change so that each parameter is applied at a different time. However, in step s2.6 it is assumed that the transition function is always valid.

In contrast, the throttle flap changes that occur before the current period do not affect the method described with reference to FIGS. 7 and 8.

In the above two methods, two of the three parameters of equation (1) are determined from the characteristic group, i.e., the final pressure pStat and the time constant kp, which values depend on the throttle flap angle α and the velocity value at the present period. Change. Therefore, the stop pressure pStat (n) is determined as a group of stop pressure characteristics 28 specifying the values α (n) and w (n), and the value kp (n) of the time constant valid for that value is designated as the value. It is determined as a possible time constant characteristic group. The values of the stop pressure and the time constant are supplied to the equation calculating means 30, to which the current suction pipe pressure value pS (n) is also applied. The third parameter to can be calculated from equation (1) by using the measured value. When this calculation is made, the suction pressure pS (n + 1) that occurs during the next cycle is calculated by equation (1). Therefore, in this method all three parameters are determined based on the currently available measurements.

Thus, in the non-stop mode, the accuracy is further increased, compared with the accuracy that can be achieved in the method described with reference to FIG. However, in the stop mode, the method of setting the pressure measurement becomes somewhat more accurate since it is not accompanied by characteristic values.

The method described with reference to FIG. 8 now takes place with very simple means. In particular, this method does not require a pressure measurement and in any case only uses the throttle flap angle α and speed w values available on the internal combustion engine. The characteristic groups described above with reference to FIG. 7 are designated by these values. The method of FIG. 8 differs from the method of FIG. 7 in that the suction pipe pressure pS (n) is determined from the ignition formula of the ignition calculation means 31, not measured. This is done according to the following equation.

The suction pipe pressure pS (n + 1) for the next period determined to be this ignition type is stored in the calculation means in the next cycle, which is indicated by the sensing / holding means 32 in FIG. In subsequent cycles, the pressure pS (n + 1) during the next cycle, calculated in this manner, becomes the current pressure value pS (n). The argument G and the time constant kp can be interchanged as shown in equation (1). The method has advantages and disadvantages over the method of FIG. 7 but has advantages over the method of FIG. 7 in that it does not require a relatively expensive pressure sensor. In contrast, there is a disadvantage in that an error is transmitted in the calculation of the suction pipe pressure because a value which is not calculated completely correctly during the next period is related to the current value which is correctly assumed in the next calculation.

Compared to the method of FIG. 6 and FIG. 7, the method of FIG. 7 and the method of FIG. 8 are very new, although these values are characteristic groups (where slightly inaccurate values can often be established for internal combustion engines). There is a disadvantage that must be determined from. These shortcomings can be addressed through coordination. Embodiments of such a method are described in detail with reference to FIG. In a first step s1.9 of the adjustment method according to FIG. 9, the suction pipe pressure pS (n) generated during the current period n is measured. In step s2.9, this measured value is compared with the pressure value calculated in the previous period during the next period. In step s3.9, when two values deviate from each other by a difference greater than a predetermined limit value ΔpS, the value that the time integer g must possess is calculated and the value measured in the current period by the calculation in the previous period. Will be provided. When this value is determined, the values determined as the correlation values of the throttle flap angle and speed are corrected with the newly calculated values. For the way in which such corrections are made, see German Federal Republic of Germany Patent Study No. 36 03137 A1, which describes further adjustment methods.

When step s3.9 ends or a negative answer is given to the question in step s2.9, step s4.9 is reached. In this step, it is checked whether or not a stop operating state exists. If no stop operational state exists, the method returns to step s1.9. In contrast, when there is a stop operating state, the stop pressure pStat (α, w) is measured in step s5.9. In step s6.9, it is checked whether the measured value differs more than the predetermined limit value? PStat from the input value stored as the present values of the designated variables? And w. If there is a difference, the characteristic value is corrected to the measured value in step s7.9. Therefore, in the correction | amendment of a time constant characteristic group, the said statement is applied in the detail of this. After the end of step s7.9 and also a negative answer to the question in step s6.9, the method returns to step s1.9.

The method according to 6, 7 or 8 and 9 can also be carried out jointly. For example, all of the above methods operate continuously in parallel. If no change in the throttle flap occurs before the last three measurements are made, the pressure value calculated by the method means according to FIG. 6 is used. In contrast, if a change in the throttle flap occurs, the pressure value calculated by the method means according to FIG. 7 or 8 is used. In the manner described above, adjustments to the feature group occur continuously.

In the description of the present technology, a system in series has been described in which the suction pressure is continuously measured and the injection time for the subsequent suction stroke is calculated from the current suction pressure value. In this type of system, the accuracy in determining the control value is determined using the suction pressure determined by the method according to the invention, i.e. at the next suction stroke of a particular cylinder, the previous measured pressure rather than the current measured suction pressure. It can be significantly improved when using the suction pressure calculated at.

As already briefly mentioned above with reference to FIGS. 3 and 5, further improvements are obtained if the calculated values are also modified by the air mass mLT with temperature. This measurement is also performed without any calculation of the suction pressure described above, ie when the suction tube pressure currently measured is used as the predominant suction tube pressure for the next cycle.

The temperature-dependent modification is based on the fact that the mass flowing into the intake tube and the engine is assigned differently when both the intake tube and the engine are relatively cold and when the intake tube is cold and the engine is hot. Therefore, the mass of air flowing into the engine for combustion depends not only on the suction line pressure but also on the temperature difference. The time operation due to the temperature influence is relatively closely simulated by the second order transition function, which essentially has only one parameter that is closely dependent on the operating variable value increase and stop temperature ΔTStat. The stop temperature can be addressed via throttle flap angle, speed and engine temperature values, i.e., ΔTStat (n) = f (α (n), w (n), tw (n)). Are recorded in the system of auxiliary-temperature-change characteristics 26. The ignition type is as follows.

The constant values k1 (n) and k2 (n) are also read from the system of auxiliary-temperature-change characteristics in a corresponding manner with respect to the quiescent temperature ΔTStat (n). By these changes, the above-mentioned ignition equation 3 is calculated in the means 27 for calculating the ignition equation.

The auxiliary variable ΔT used to correct the tentatively calculated air mass mLV is used to simply clarify the dimension of the temperature, indicating that the effect modified by it is mainly the effect of temperature. Modification variables are also directly dimensioned. The effects in addition to the temperature effect, in particular the vibration effect, are considered by modifying the above-mentioned ignition equation and also by multiplication by, for example, a triangular vibration function.

In addition to the corrections considered, the mass of air provided to the fuel is obtained as follows.

The adjustment method is also performed in relation to mL of air mass.

For this reason, the calculated air mass mL (n + 1) is compared with the air mass actually inhaled during cycle n + 1. For example, this measurement is made by an air mass meter which detects the air mass flow. Suction mass is obtained from the mass flow and suction time. If the difference between the actually inhaled air mass and the calculated air mass exceeds the limit, the stop temperature TStat is preferably calculated in reverse, whereby the corrected stop temperature gives the corrected air mass. Then, the modified stop temperature is recorded in the system of characteristic 26.

Starting from the calculated air mass mL (n + 1), the ignition time is set on the one hand and the fuel mass applied to this air mass on the other hand is calculated. The setting of the ignition time is performed by selecting a conventional system of speed / air / mass / ignition time characteristics. If the conventional system characteristic selection is not already made by the currently measured air mass value, there is an advantage made by means of conventional calculated values. The ignition time is calculated from the velocity and air mass values by equations instead of from the characteristic system. In this case also, the calculation is carried out by the predetermined air mass value and not by the current air mass value.

The fuel mass is calculated from the air mass by the predetermined desired lambda value lambda SOLL (n + 1) in the drive stage 27. The fuel mass obtained by dividing the air mass mL (n + 1) by the preferred value is only the potential fuel mass mkV (n + 1). It is provisional because it still needs to consider how much fuel is included in the build-up of the wall when the fuel supply is increased or how much fuel is obtained from the removal of the wall when the fuel supply is reduced. Wall modification is accomplished by a known method in which the transient A / F control characteristics of a 51 central fuel injection engine manufactured by C.F Aquino are preferably described in SAE Paper 81 0494, page 115. Therefore, the time change of the wall fuel mass mKF is calculated from the fuel supply mass mkZ according to the following equation.

Where X = sedimentation rate

T = evaporation time constant

From this result, the transition fuel amount mK generated by fusing in the wall or the interior thereof as shown in the following equation Is

Then, the actual amount of fuel injected with mk (n + 1) is calculated as follows.

The above-mentioned transition function and the ignition equation for calculating the suction pipe pressure or temperature influences only point to the example that emerges from the preliminary measurement. For special uses, other transition functions and associated ignitions also explain much better the conditions actually measured. Two methods are used for the critical elements, each of which is improved by known methods. The methods are each used individually or in combination. Regardless of how this is determined, by means of a temperature-effect model, one method involves precomputing a particularly predominant suction tube pressure during the next suction cycle and the other method includes a modification of the suction tube pressure.

For the sake of simplicity, assuming that the computing cycle occurs in each cylinder, ie in each case for the intake stroke of a four stroke engine, the calculation is repeated every 720 ° of the crank-angle for each cylinder. However, the intake stroke of a four-cylinder four-stroke engine is offset at only 180 ° relative to each other, which means that the calculation is performed separately for all four cylinders and for each cylinder. In the next calculation that includes each value for this cylinder, it is necessary to store the final calculated value. For each cylinder, changed conditions, in particular changed positional adjustment of the trough flap, occur only every 720 °. Therefore, an easy-to-understand process has many disadvantages.

By referring also to FIG. 10, a procedure for avoiding the above disadvantages is now described. In FIG. 10 each suction stroke for four cylinders z1-z4 is plotted as if each of the boxes of the same length, ie the same crank-angle, overlapped. Since the special suction pipe pressure is calculated in the middle of the suction stroke, the injected fuel mass is determined from this. The middle of all suction strokes are each at a distance of 180 ° from each other. Marks M1-M4 are related in between. Mark M1 clearly indicates at the crank-angle whether the fuel mass has been injected into the cylinder ZI, so it inhales this fuel during its next intake cycle. In this situation described, the mark M1 is located at the crank-angle zero and the middle of the associated suction stroke is 540 °. Calculation of the fuel mass begins when the crank angle is small before a mark appears, so the calculation results can be used when the mark appears.

Starting from these predetermined conditions, the evaluation of the ignition formula 2 with respect to the suction pipe pressure is now described.

Since the calculation of the suction tube pressure is performed every 180 °, the constant value G (α (n) (, W (N)) is recorded for each time difference at which the 180 ° crank-angle overlaps at a specific speed. Once 2) is calculated, a suction tube pressure is obtained, perhaps occurring later than 180 °, i.e. before mark M2 is set, however, since the suction tube pressure remains at mark M4, the ignition equation is more than twice according to equation (2). Therefore, immediately before the symbol M1 appears, the evaluation value of the ignition formula (2) is rapidly generated three times in succession, so when the mark M1 appears, the amount of fuel injected into the intake stroke of the cylinder Z1 generated at the mark M4 The results of the calculations for each iteration can be used to memorize intermediate results for individual iteration calculations, especially for the following reasons: The results of the first calculation using the iterations indicate that the iteration marks M2. When executed three times immediately before, the initial value is formed to calculate the fuel value required for the intake stroke of Z2 around the next mark M1.If a repeat formula is used with the initial value, the result is that the mark M1 appears. Corresponds to what is obtained after the second use of the iteration formula just before, but if the position of the throttle flap changes in the middle, there is no correspondence. Appropriately used to correct the fuel amount for the intake stroke, if more fuel than the first one is calculated, the difference amount is additionally injected.If less fuel is required than already injected, the difference value for cylinder Z1 The next injection is subtracted, if only a slight progress has been made in the current operating state, ie when the mark M2 appears the mark M note If the fuel for the intake stroke of the cylinder Z1 above has not been injected yet, the required amount of fuel is recalculated.

It is also possible to cover smaller angular sectors, for example 60 °, in each iteration step rather than 180 °. The calculation mark is then output every 60 ° crank angle. For these calculation marks not located directly in front of one of the marks M1 to M4, the repeating formula 2 is used only once. In contrast, in the calculations performed immediately before one of the marks M1 to M4, the iteration formula is calculated nine times in succession to predict the suction tube pressure over the time when the crank angle covers 540 °. The smaller the angular sector covered by the iteration formula, the more updated the application for possible changes in the throttle flap angle, but the higher the computational cost.

Predictions occurring above each 540 ° sector are unnecessary. This sector was not selected in the specific embodiment because it covers the longest run time. If the method is used in an engine with a smaller maximum run time, the calculation thus covers smaller angular sectors. Therefore, the above description of the calculation of equation (2) applies to the calculation of equation (3) for the auxiliary temperature variable ΔT.

Claims (5)

A method of determining the amount of fuel supplied to the internal combustion engine according to the operating voltage during each intake stroke by calculation occurring in a calculation cycle, wherein the amount of air sucked for combustion during each intake stroke is determined by the intake pipe pressure; A fuel amount determining method supplied to an internal combustion engine comprising the step of determining the amount of fuel supplied during each intake stroke from the air amount in consideration of the wall model, wherein a factor G (n) corresponding to the time constant when the inlet pipe pressure changes And the associated suction line pressure is determined by a variable value indicative of the air intake section and the engine speed, and using this value, the suction line pressure PS (n + 1) for a critical and future occurrence in the intake stroke and A method for determining the amount of fuel supplied to an internal combustion engine, which is calculated by a repetition formula. 2. A method according to claim 1, wherein each value for the intake pressure can be read from a family. A method according to claim 1, wherein each value for the factor G (n) can be read from the characteristic group. The temperature influence from the relationship according to any one of claims 1 to 3, taken into account in calculating the amount of preliminary air sucked in for combustion and between the operating variable value and the specific calibration value, the relationship set to regulate the internal combustion engine. And a preliminary air amount correction calculated based on the air amount correction value. 4. A method according to any one of claims 1 to 3, wherein the ignition time in each stroke is determined from the air quantity value in a conventional manner, and the predicted calculated value is used as the air quantity value. .