DE102017122934A1 - Method for controlling an exhaust gas behavior of an internal combustion engine - Google Patents

Abstract

The invention relates to a method for controlling an exhaust gas behavior of an internal combustion engine (2) of a vehicle (1), with a control unit (3) of the internal combustion engine (2) having a reference value (43.1, 43.2) for an emission of an exhaust gas component in real time during an operation Internal combustion engine (2) is determined and calculations of multiple integrals of a mass flow of the exhaust gas component offset in time and a period between starting a calculation of an integral of the mass flow of the exhaust gas component and triggering starting a calculation of another integral of the mass flow of the exhaust gas component to a driving condition of Vehicle (1) is adjusted.

Description

The invention relates to a method for controlling an exhaust gas behavior of an internal combustion engine of a vehicle.

Such a method is from the Document "RDE Data Evaluation Using The Moving Average Window Method", published by the European Commission Joint Research Center (ECJRC) in May 2014 , known. The document describes a procedure of the software EMROAD for the execution of exhaust gas tests. In this method, after a test drive, an emission value for an exhaust gas component is determined on the basis of a mass flow profile of the exhaust gas component in relation to a covered distance of the vehicle. In this case, calculations of several integrals of the mass flow of the exhaust gas component are started in succession. The time interval from a start of a calculation to a start of a subsequent calculation of the integrals is predetermined with a time step size. However, this time increment is so small and a required memory correspondingly large that in an implementation of the method on a control unit of the internal combustion engine operation in real time is difficult. An increase in the time step size does not solve this problem satisfactorily, as changes in a state of the internal combustion engine can thereby be detected much more difficult and could falsify the result.

The object of the present invention is therefore to provide a method for controlling an exhaust gas behavior of an internal combustion engine which can be executed in real time on a control unit of the internal combustion engine.

This object is achieved by a method according to claim 1 and an internal combustion engine according to claim 10. Further advantageous embodiments will become apparent from the dependent claims.

To solve this problem, a method for controlling an exhaust gas behavior of an internal combustion engine of a vehicle is proposed. In this method, a reference value for an emission of an exhaust gas component during operation of the internal combustion engine is determined in real time with a control unit of the internal combustion engine.

For this purpose, several integrals of a mass flow of the exhaust gas component detected by means of the control unit are calculated. The calculations of the integrals of the mass flow of the exhaust gas component are started offset in time. Upon starting a calculation of an integral of the mass flow of the exhaust gas component, a calculation of an integral of a state quantity of the vehicle is triggered. After an integral value of the integral of the state variable has increased by a predetermined threshold value, a start of a calculation of a further integral of the mass flow of the exhaust gas component is triggered.

The calculations of the integrals of the mass flow of the exhaust gas component are terminated as soon as a respective calculated integral value of the integral of the mass flow of the exhaust gas component is greater than or equal to a predetermined mass of the exhaust gas component.

Furthermore, in each case a corresponding traveled distance of the vehicle is measured in relation to the integrals of the mass flow of the exhaust gas component. The measurement of the respective corresponding traveled distance starts at a time of starting the calculation of the corresponding integral of the mass flow of the exhaust gas component and ends at a time of stopping the calculation of the corresponding integral of the mass flow of the exhaust gas component. In addition, a respective corresponding normalized emission value for the exhaust gas component is calculated from the integral value of the integral of the mass flow of the exhaust gas component and each of the corresponding traveled distance.

Furthermore, a respective corresponding average speed of the vehicle is detected for the respective integral of the mass flow of the exhaust gas component, the respective distance traveled or the respective normalized emission value. On the basis of the detected corresponding average speeds, the respective normalized emission values are assigned to a first, second or third speed range.

The inventive method further provides that the reference value is determined from the normalized emission values, wherein at least three of the normalized emission values are used, which were assigned to the first, second and third speed range. When determining the reference value, the normalized emission values are weighted as a function of the corresponding average speeds and / or a variable describing an operating state of the internal combustion engine. To check the exhaust gas behavior of the internal combustion engine, the reference value is compared with a desired value.

An integral of the mass flow of the exhaust gas component is referred to below as the integral of the mass flow. The sequence of steps listed here is only an example Sequence of steps there. The method may also provide a different order of steps. In addition, the steps of the proposed method can be partially performed in parallel. For example, the calculation of the integral of the mass flow may continue to be performed upon the initiation of the start of the calculation of the further integral of the mass flow. In the same way, a weighting of a normalized emission value can be carried out before the normalized emission value is assigned to a speed range.

The individual normalized emission values are preferably calculated in each case from a quotient with the corresponding integral value of the integral of the mass flow as a dividend and the corresponding traveled distance as a divisor. The exhaust gas component may be carbon dioxide, carbon black, sulfur oxide or nitric oxide, i. Nitric oxide or nitrogen dioxide, be.

Furthermore, all integrals preferably have the time as an integration variable. By an integral of a mass flow, a velocity or a state variable is meant an integral with a mass flow, a velocity or a state variable as integrand. A calculation of an integral means an integration as such, in particular a numerical integration. An integral value can be determined from a calculation of an integral. The measurement of the corresponding traveled distances can each take place by measuring a current speed of the vehicle and calculating a respective integral of the current speed of the vehicle.

It is particularly advantageous in the proposed method that the starting of the calculation of the further integral of the mass flow is triggered after the integral value of the integral of the state variable has increased by the predetermined threshold value. Thus, between starting the computations of the integrals of the mass flow, a time period that depends on a progression of the state variable of the vehicle over time elapses.

In a particular embodiment of the method, the state variable is an emitted carbon dioxide mass flow, a power of the internal combustion engine or a speed of the vehicle. Such a configuration of the method causes the time period to become smaller the higher a value of the state quantity is during a part of the time period. Conversely, the lower the value of the state variable during another part of the time span, the larger the time span.

For example, at a standstill of the vehicle, the time span is greater than during a driving operation of the vehicle, because an output power of the internal combustion engine is smaller compared to the driving operation. When the vehicle is operating at an acceleration, the output power or the carbon dioxide mass flow is higher than when traveling at a constant speed and the time is shorter compared to the operation in this overland travel. The length of the time span is thus adapted to the course of the state variable during the time span.

The greater the amount of time, the less mass flow integral calculations are performed per time and the less integral values of the individual mass flow integrals are calculated per time and must be stored in the controller. Accordingly, a greater period of time reduces the required computing power of the control unit on which the method is carried out and, secondly, a required memory of the control unit. This reduction makes it possible in particular for the proposed method to be carried out in real time on the control unit of the internal combustion engine.

A further advantage of the proposed method is that at least three of the normalized emission values assigned to the first, second and third speed ranges are used when determining the reference value. This has the advantage that each of the three speed ranges is taken into account when determining the reference value. When determining the reference value, it is advantageous to use a predetermined number of normalized emission values that have been assigned to the first, second or third speed range. Thus, the reference value can be determined based on a driving profile representing a test cycle. The test cycle preferably includes city, overland and highway travel.

In a further refinement of the method, it is provided that those normalized emission values which were last assigned to the respective speed ranges are used to determine the reference value. As a result, the reference value takes into account the exhaust gas behavior of the vehicle, at least during three last-traveled routes at at least three different speeds, the respective speeds being within the first, second or third speed range. A reference value determined in this way is referred to below as the current reference value. The current reference value can in particular represent actual exhaust performance of the internal combustion engine under conditions similar to exhaust test conditions. By determining the current reference value, it is possible to detect a change in a component of an exhaust system of the internal combustion engine, for example due to aging effects.

According to a development of the method, the exhaust gas component carbon dioxide and the state variable of the vehicle is a carbon dioxide mass flow. Furthermore, the reference value is a reference value for the emission of carbon dioxide, wherein the threshold value and the predetermined mass of the exhaust gas component are constant in the calculations of the integrals of the mass flow of the exhaust gas component.

According to this embodiment, the mass flow of the exhaust gas component is also the state variable. The particular advantage of this variant is that a number of calculations of the integrals of the mass flow, which is performed simultaneously in the controller, is constant over time. The vectors and matrices and storage elements for the vectors and matrices used in the controller for carrying out the method may therefore have constant sizing over time. This can be dispensed with a new allocation of memory elements during the process. This can have the effect that a required size of the storage elements in the control unit when carrying out the proposed method is independent of an operating state and / or a change in an operating state of the internal combustion engine. As a result, an implementation of the method on the control unit in real time can be simplified or only possible.

The integration of the state variable can be done in addition to the integration of the mass flow. In this case, an additional integrator is started. Another variant provides that a difference is formed from a current integral value of one of the integrals of the mass flow and an integral value at the start time of the calculation of this integral. The difference can be compared to the threshold. As soon as the difference is greater than or equal to the threshold value, the calculation of the further integral of the mass flow is started. This has the advantage that no additional integrator for the integration of the state variable is needed.

In the event that the mass flow is a carbon dioxide mass flow, the normalized emission values are preferably weighted on the basis of the corresponding average speeds.

In a further advantageous embodiment of the method, a calculation of a first integral and a second integral of the mass flow are respectively divided. Furthermore, at least part of the calculation of the first integral and part of the calculation of the second integral begin and end at the same time, these parts of the calculations being performed with a single integrator. This has the advantage that a calculation of two integrals of the mass flow can be carried out at least partially or completely with a single integrator instead of two integrators. This further reduces the required computing power and space required by the controller. Particularly advantageously, all calculations of the integrals of the mass flow are divided and carried out with a single integrator.

In a particular embodiment, it is provided that the exhaust gas component is carbon dioxide and, in addition to the reference value for the emission of carbon dioxide, a reference value for an emission of nitrogen oxide in real time is determined. This is preferably done with the following steps. First, a respective integral of a mass flow of nitrogen oxide is calculated to the respective integral of the mass flow of carbon dioxide. The respective calculation of the corresponding integral of the mass flow of nitrogen oxide is started at a same starting time as the calculation of the corresponding integral of the mass flow of carbon dioxide and is terminated at the same end time as this calculation.

Furthermore, in each case one corresponding normalized emission value for nitrogen oxide is calculated from an integral value of an integral of the mass flow of nitrogen oxide and in each case the corresponding distance traveled by the vehicle. The normalized emission levels for nitrogen oxide are each assigned to the first, second or third speed range based on the detected corresponding corresponding average speeds.

In a further step, the reference value for the emission of nitrogen oxide from the normalized emission values for nitrogen oxide is determined. At least three of the standardized emission values for nitrogen oxide, which were assigned to the first, second or third speed range, are used. A weighting of the respective standardized emission values for nitrogen oxide takes place at least as a function of the corresponding corresponding normalized emission values for carbon dioxide. Subsequently, the reference value for the emission of nitric oxide is compared with a target value for emission of nitrogen oxide.

Through the synchronous calculations of the integrals of the mass flow of nitrogen oxide to the calculations of the integrals of the mass flow of carbon dioxide, a determination of the reference value for the emission of nitrogen oxide in real time is possible. The advantage of a weighting as a function of the standardized emission values of carbon dioxide is that an influence of a load of the internal combustion engine on the nitrogen oxide emissions is taken into account.

In a further development, it is provided that the reference value is used to control the internal combustion engine. In this variant, a deviation of the reference value from the desired value, for example, a legal specification, is preferably calculated. Depending on the deviation, a control variable is calculated with a controller, which acts on a component of the internal combustion engine. Thus, for example, an ammonia dosage can be increased if the reference value for the emission of nitrogen oxide is above the setpoint for emission of nitrogen oxide.

Because the reference value is determined in real time, the reference value, in particular the current reference value, can be used at any time during operation of the internal combustion engine for regulating the internal combustion engine. Thus, the emissions, in particular of nitrogen oxide, the internal combustion engine can be controlled more accurately. The more accurate control allows an application of the internal combustion engine with a lower or no safety distance to a limit value for the emissions of nitrogen oxide can be performed. As a result, permissible value ranges for parameters enabling a more economical operation of the internal combustion engine can be increased, for example a permissible value range for an injection quantity of fuel, an injection time, an air ratio or an exhaust gas recirculation rate.

Another possibility is to use the reference value for an application of the internal combustion engine. Due to the fact that the reference value represents an emission behavior of the last traveled distances at corresponding speeds, a renewed application can take place while performing a shortened test drive of the vehicle. Furthermore, the reference value can be used to monitor the internal combustion engine. For example, after determining a reference value which is high in comparison with normal operation, a control display can issue a warning to a driver.

According to a further embodiment, the normalized emission values are assigned to the speed ranges during an entire drive of the vehicle. In this case, the reference value represents an exhaust performance of the internal combustion engine for the entire trip. This can allow a more environmentally friendly driving of the vehicle, because a feedback is provided to a driver of the vehicle about his driving behavior.

Further advantages, features and details of the invention will become apparent from the following description of at least one preferred embodiment and with reference to the figures. These show in:

1 a vehicle with an internal combustion engine and an exhaust aftertreatment system,

2 a representation of an integration of a mass flow of an exhaust gas component,

3 calculated integral values for different time windows,

4 a representation of an integration of a mass flow of nitrogen oxide,

5 Steps for forming a reference value for emission of an exhaust gas component,

6 normalized emission levels of carbon dioxide as a function of average speed,

7 a weighting factor as a function of a relative normalized emission of carbon dioxide,

8th a subdivision of a speed interval,

9 an influence of a control with the reference value for the emission of the exhaust gas component.

1 shows a vehicle 1 comprising an internal combustion engine 2 with a control unit 3 and an exhaust aftertreatment system 4 with a sensor 5 , The control unit 3 detects a current state variable of the vehicle 1 , The state quantity may be a speed of the vehicle 1 or one with the sensor 5 measured mass flow 6 an exhaust gas component in the exhaust aftertreatment system 4 be. A variant provides that the control unit 3 a virtual sensor 7 with which a value of the state variable based on further state variables of the vehicle 1 is modeled.

2 shows a course 10 an accumulated from the internal combustion engine 2 emitted mass 11 the exhaust gas component during a time interval 11.1 , preferably a driving cycle of the internal combustion engine 2 , Furthermore, a first, second, third, fourth, fifth, sixth, seventh and eighth time window with a corresponding reference numeral 12 . 13 . 14 . 15 . 16 . 17 . 18 and 19 shown.

The time windows each represent a calculation of an integral of the mass flow 6 within the time interval 11.1 , A width of a time window along a horizontal axis indicates a duration of the respective calculation in minutes and a height of a time window along a vertical axis an integral value of the calculated respective integral at the end of the respective calculation in grams. It can be seen that the calculations of the individual integrals overlap in time and are started with a time offset from one another. After starting a calculation of a first integral of the mass flow 6 a calculation of an integral of the state variable is triggered.

At the in 2 The example shown is the state variable of the mass flow 6 , If the integral value of the integral of the state variable has a predetermined threshold value 21 is increased, starting a calculation of another integral of the mass flow 6 triggered. The calculations of the individual integrals of the mass flow 6 are each terminated as soon as a respective calculated integral value of a single integral of the mass flow 6 equal to a given mass 20 the exhaust gas component is, for example, 30 grams as in a table in FIG 3 is shown. Out 2 it can be seen that the height of all time windows 12 . 13 . 14 . 15 . 16 . 17 . 18 and 19 is equal to. This value corresponds to the case in which the exhaust gas component is carbon dioxide, preferably one half of an emitted carbon dioxide mass of the internal combustion engine 2 during an entire test cycle, especially during a chassis dynamometer cycle.

In the following it is assumed that the exhaust gas component is carbon dioxide. Particularly advantageous is an increase in the integral value of the state variable by the predetermined threshold value 21 not just the respective calculation of an integral of the mass flow 6 from carbon dioxide, but also a calculation of a respective corresponding integral of a mass flow of nitrogen oxide, a speed of the vehicle and time. The computations of these corresponding integrals become the same times as the computations of the respective integrals of the mass flow 6 started and stopped. An integral value of the integral of the speed of the vehicle at the end of the calculation of this integral corresponds to a distance covered by the vehicle in a period from a start of the calculation of this integral to an end of the calculation of this integral.

3 shows in the table by way of example respective integral values of the integrals of the mass flow 6 of carbon dioxide, the mass flow of nitric oxide, the speed of the vehicle 1 and the time, which at the end of the respective time window 12 . 13 . 14 . 15 . 16 . 17 . 18 and 19 were calculated. The end of the calculation in the time window 19 . 18 . 17 . 16 . 15 . 14 . 13 . 12 corresponds in each case to a time t + 1, t, t-1, t-2, t-3, t-4, t-5, t-6. The numerical values given in the table are only examples and do not indicate a duration of the respective in 2 shown time window again.

At the end of each time window, the calculated integral values are preferably stored in a vector t, t-1, t-2, t-3, t-4, t-5, t-6 and t + 1, respectively. In the control unit 3 Preferably, the last seven vectors, ie the computations of the integrals within the last seven time windows, are stored. If a new time window is started, such as the time window 19 , at the end of the time window, ie at the end of the calculation of the integrals, a new vector t + 1 is stored in the control unit and the oldest vector, here t - 6, from a memory of the control unit 3 deleted. To calculate a reference value for an emission of an exhaust gas component, those in the control unit 3 stored integral values, ie in particular only the respectively last determined integral values used.

4 shows a course 30 the accumulated mass 11 of carbon dioxide as a function of an accumulated mass 31 of nitric oxide during the time interval 11.1 , Furthermore, a first, second, third, fourth, fifth, sixth, seventh and eighth window with a corresponding reference numeral 32 . 33 . 34 . 35 . 36 . 37 . 38 and 39 shown.

The window 32 . 33 . 34 . 35 . 36 . 37 . 38 and 39 each represents one to each calculation of an integral of the mass flow 6 Corresponding calculation of an integral of the mass flow of nitrogen oxide within the time interval 11.1 , A width of a window along a horizontal axis indicates an integral value of the individual integrals of the mass flow of nitric oxide at the end of the respective calculation in grams. A height of a window along a vertical axis gives an integral value of a respective integral of the mass flow 6 of carbon dioxide in grams at the end of the calculation in the time windows 12 . 13 . 14 . 15 . 16 . 17 . 18 and 19 or the windows 32 . 33 . 34 . 35 . 36 . 37 . 38 and 39 at. This height is for all windows 32 . 33 . 34 . 35 . 36 . 37 . 38 and 39 equal and corresponds to the given mass 20 of carbon dioxide, for example 30 grams as in the table in 3 shown. The calculations of the individual corresponding integrals of the mass flow of nitrogen oxide are started after the integral value of the integral of the state variable is around the threshold value 21 has increased and stopped after the integral values of the respective integrals of the mass flow 6 the given mass 20 of carbon dioxide.

At every time window 12 . 13 . 14 . 15 . 16 . 17 . 18 and 19 , ie to each integral of the mass flow 6 , in each case a corresponding average speed 44 of the vehicle 1 in the calculation of the respective integrals of the mass flow 6 , a corresponding normalized emission value for carbon dioxide 41 and a corresponding normalized emission level for nitric oxide 42 calculated.

With the in 5 shown process steps from the normalized emission values for carbon dioxide 41 and the normalized emission levels for nitric oxide 42 a reference value 43.2 formed for emission of nitric oxide. First, for each time slot 12 . 13 . 14 . 15 . 16 . 17 . 18 and 19 a weighting of the corresponding normalized emission value for carbon dioxide 41 and the corresponding normalized emission value for nitrogen oxide 42 , The weighting of the standardized emission values 41 and 42 is preferably done by multiplication by a factor. The factor can be used, for example, for the standardized emission value for carbon dioxide 41 depending on the corresponding average speed 44 vary between 0 and 1.

Depending on the average speed 44 during the calculations of the integrals are weighted and normalized emission levels for nitric oxide 48 or in detail 48.1 . 48.2 . 48.3 . 48.4 . 49.1 . 49.2 . 49.3 . 49.4 . 50.1 . 51.2 . 51.3 and 52.4 , assigned to a first, second or third speed range. The first speed range 45.1 preferably includes speeds between 0 and 45 km / h, the second speed range 45.2 Speeds between 45 and 80 km / h and the third speed range 45.3 Speeds over 80 km / h. In 5 is an assignment of the weighted and normalized emission values 48 for nitric oxide to the respective speed ranges 45.1 . 45.2 and 45.3 shown.

Due to the weighting of the standardized emission values for nitrogen oxide 42 is it possible that of the in 3 shown 7 time windows and their determined integral values are only 4 time windows after a weighting relevant and for a determination of the reference value 43.2 be used for the emission of nitric oxide.

From the weighted and standardized emission values for nitrogen oxide 48 will be in a subsequent step 46 the reference value 43.2 formed for the emission of nitric oxide. Here, the reference value 43.2 as an average of all weighted and normalized emission levels for nitric oxide 48 be formed. This reference value 43.2 can be compared with a setpoint value, for example a legally prescribed maximum value for emission of nitrogen oxide. In 5 are the steps for determining the reference value 43.2 represented for the emission of nitrogen oxide. A determination of a reference value 43.1 for emission of carbon dioxide preferably comprises the same steps, except that the normalized emission levels for nitrogen oxide 42 preferably not used.

Based on 6 should be an exemplary weighting of the standardized emission values for carbon dioxide 41 to be discribed. In the graphic in 6 are single normalized emission levels for carbon dioxide 41 , which were determined for a respective time window, over respective corresponding average speeds 44 plotted during the respective time window. This shows a solid curve 51 Normalized carbon dioxide emission levels determined by a prior art test method and a dashed curve 52 standardized emission levels for carbon dioxide 41 , which were determined by the method according to the invention. Every point of the curve 52 provides a normalized emission level for carbon dioxide 41 which was calculated at the end of a time window. Different emission levels can result, for example, from ascents or descents.

In addition, a first curve represents 53 standardized emission levels for carbon dioxide as a function of a respective corresponding average speed in a chassis dynamometer test. A second turn 54 and a third curve 55 define an area 58 , within which the normalized emission levels for carbon dioxide 41 in a calculation of the reference value 43.1 for the emission of carbon dioxide and / or the reference value 43.2 for the emission of nitric oxide. Outside the area 58 become the normalized emission levels for carbon dioxide 41 not considered for the calculation of the reference value for the emission of carbon dioxide. These are in particular emission values, which at comparatively high and low load of the internal combustion engine 2 were recorded.

In addition, it is possible the respective normalized emission levels for carbon dioxide 41 between 0 and 1, depending on how far the normalized emission levels for carbon dioxide 41 from the first bend 53 are spaced. In this case, an additional division into several subregions by a fourth curve 56 and a fifth turn 57 made or a linear interpolation be performed.

7 shows a function for determining a weighting factor 61 for the weighting of the standardized emission values for nitrogen oxide 42 , The weighting factor 61 is in this example dependent on a respective ratio 62 the respective calculated normalized emission levels for carbon dioxide 41 and a corresponding normalized emission value of the first curve 53 at the same respective average speeds 44 , At a ratio 62 from 75% to 125% takes the weighting factor 61 the value 1, while at a ratio 62 from 0 to 50% and at a ratio 62 of 150% and greater assumes a value of zero. Between a relationship 62 of 50 and 75% and a ratio 62 of 125 and 150% becomes the weighting factor 61 linear interpolated. The advantage of such a weighting is that a dependence of the normalized emission values for nitrogen oxide 42 from a load of the internal combustion engine 2 is taken into account. Thus, the normalized emission values for nitrogen oxide become dependent on an operating state of the internal combustion engine 2 descriptive size, here's the ratio 62 , weighted.

In 8th are medium speeds 44 , which were determined for each one time window, over a number of time windows 72 shown. A speed interval 73 from 0 to 120 km / h is used to determine the reference value 43.1 . 43.2 for the emission of carbon dioxide or nitrogen oxide divided into three or eight speed ranges. A subdivision into more than three speed ranges has the advantage that a more accurate determination of the reference value 43.1 . 43.2 is possible. Preferably, the first, second, third, fourth, fifth, sixth, seventh and eighth speed ranges are each between 0 and 25 km / h, 25 and 35 km / h, 35 and 45 km / h, 45 and 60 km / h, 60 and 80 km / h, 80 and 100 km / h, 100 and 110 km / h and 110 and 120 km / h. Such a classification can cause the normalized emission values 41 . 42 , which have been assigned to the respective speed ranges, in the determination of the reference value 43.1 . 43.2 be represented in more detail.

In 9 are a first graph 81 and a second graph 82 shown, which in each case a course of determined nitrogen oxide emissions of the internal combustion engine 2 over a covered distance of the vehicle 1 play. The first graph 81 shows the course of the nitrogen oxide emissions, wherein after a distance traveled of about 3,000 km, an increase in an emission of nitrogen oxide is detected, for example by wear of an injection nozzle. A third graph 83 shows an injection rate of ammonia in an SCR catalyst of the exhaust aftertreatment system 4 in a range of 0.5 and 1.5. After increasing the emission of nitric oxide, the injection rate is increased, but the first graph diverges 81 further from a target value 84 the emissions of nitric oxide. If, however, a regulation with a calculation of the reference value 43.2 For the emissions of nitrogen oxide carried out according to the proposed method, the second graph is obtained 82 corresponding course of emissions of nitric oxide. The second graph 82 is closer to the target value 84 as the first graph 81 ,

Based on the table in 3 So far, it has been described how individual integral values for each time window are stored in each case in a vector t + 1, t, t - 1, t - 2, t - 3, t - 4, t - 5 and t - 6. The following is based on the in 3 4, how a division of the calculations of the respective integrals of the mass flow of carbon dioxide and nitrogen oxide, the speed and the time in a single time window can be made. The first five lines of the table represent a division of a calculation of a respective first integral of the mass flow of carbon dioxide and nitrogen oxide, the speed and the time during the time window 18 Each of the last five lines of the table represents a division of a calculation of a respective second integral of the mass flow of carbon dioxide and nitrogen oxide, the speed and the time during the time window 19 in each case seven partial calculations.

Accordingly, a calculation, for example, of the first integral of the mass flow of nitrogen oxide is carried out by seven partial calculations t-6, t-5, t-4, t-3, t-2, t-1 and t carried out with a single integrator. The time window 18 can be subdivided into seven subwindows t - 6, t - 5, t - 4, t - 3, t - 2, t - 1 and t. At the beginning of each subwindow, the integrator starts with a value of zero. At the end of a respective subwindow, the corresponding integral value of the mass flow of nitrogen oxide calculated with the integrator is stored in an entry t-6, t-5, t-4, t-3, t-2, t-1 and t of a vector. The integral value of the first integral of the mass flow of nitric oxide at the end of the time window 18 is formed from a sum of the entries t - 6, t - 5, t - 4, t - 3, t - 2, t - 1 and t of the vector.

To calculate the second integral of the mass flow of nitrogen oxide is only one Performing a partial calculation t + 1 of the second integral required. Subsequently, the integral value of the second integral of the mass flow of nitrogen oxide is formed from a sum of the entries t + 1, t, t-1, t-2, t-3, t-4 and t-5. The partial calculation t + 1 can be performed with the same integrator since the calculation of the first integral of the mass flow of nitrogen oxide is terminated at the beginning of the subwindow t + 1. After the end of the partial calculation t + 1, the vector has the entries t + 1, t, t-1, t-2, t-3, t-4, t-5. The oldest entry t - 6 is deleted when the newest entry t + 1 is added. Thus, the vector may represent a kind of moving time window whose sum of the entries corresponds to a current integral value of an integral of the mass flow of nitrogen oxide.

Starting the partial calculations t + 1, t, t-1, t-2, t-3, t-4 and t-5 in the example shown in the table increases the integral value of the state variable by the predetermined threshold value 21 of FIG 30 grams triggered. The state variable here is the mass flow of carbon dioxide. Thus, the carbon dioxide mass flow integrator serves as the trigger for nitrogen oxide integral calculations, velocity and time, and as a trigger for the partial calculations of these integrals and their integrators. The integrators for the sub-calculations are reset to zero each time the sub-calculations are triggered. Furthermore, it is possible to calculate normalized emission values for the respective subwindows, similar to the time windows.

According to this variant, the integral values of the mass flow of carbon dioxide would not have to be calculated for the respective time windows or subwindows, since these always have the same value. However, the time at which this integral value is reached during operation of the internal combustion engine is unknown. Thus, the integrator of the carbon dioxide mass flow is used as the trigger for the other integrators. In a further embodiment, the integrator for the covered distance of the vehicle 1 or be designed for a work performed by the internal combustion engine as a trigger of the other integrators.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• Document "RDE Data Evaluation Using The Moving Average Window Method" issued by the European Commission Joint Research Center (ECJRC) in May 2014 [0002]

Claims (10)

Method for controlling an exhaust gas behavior of an internal combustion engine ( 2 ) of a vehicle ( 1 ), whereby with a control device ( 3 ) of the internal combustion engine ( 2 ) a reference value ( 43.1 ; 43.2 ) for an emission of an exhaust gas component in real time during an operation of the internal combustion engine ( 2 ) is determined by the following steps: - calculation of several integrals by means of the control unit ( 3 ) mass flow ( 6 ) of the exhaust gas component, wherein at a start of a calculation of an integral of the mass flow ( 6 ) of the exhaust gas component, a calculation of an integral of a state variable of the vehicle ( 1 ), triggering of starting a calculation of another integral of the mass flow ( 6 ) of the exhaust gas component, after an integral value of the integral of the state variable has shifted by a predetermined threshold value ( 21 ), - ending the calculations of the integrals of the mass flow ( 6 ) of the exhaust gas component as soon as a respective calculated integral value of the integral of the mass flow ( 6 ) of the exhaust gas component is greater than or equal to a predetermined mass ( 20 ) is the exhaust gas component, - each measuring one to the respective integral of the mass flow ( 6 ) of the exhaust gas component corresponding to the covered distance of the vehicle ( 1 ), wherein measuring the respective corresponding distance traveled at a time of starting the calculation of the corresponding integral of the mass flow ( 6 ) of the exhaust gas component begins and at a time of completion of the calculation of the corresponding integral of the mass flow ( 6 ) of the exhaust gas component ends, - calculation of a respective corresponding normalized emission value for the exhaust gas component ( 41 ; 42 ) from in each case the integral value of the integral of the mass flow ( 6 ) of the exhaust gas component and in each case of the corresponding traveled distance, - detecting in each case a corresponding average speed ( 44 ) of the vehicle ( 1 ) to the respective integral of the mass flow ( 6 ) of the exhaust gas component, the respective distance traveled or the respective normalized emission value ( 41 ; 42 ), - assignment of the respective normalized emission values ( 41 ; 42 ) to a first, second or third speed range based on the detected corresponding average speeds ( 44 ), - determining the reference value ( 43.1 ; 43.2 ) for the emission of the exhaust gas component from the normalized emission values ( 41 ; 42 ), whereby at least three of the normalized emission values ( 41 ; 42 ), which have been assigned to the first, second and third speed ranges, respectively, and the normalized emission values ( 41 ; 42 ) as a function of the corresponding average speeds ( 44 ) and / or an operating state of the internal combustion engine ( 2 ) descriptive size, - comparison of the reference value ( 43.1 ; 43.2 ) with a setpoint. A method according to claim 1, characterized in that for determining the reference value ( 43.1 ; 43.2 ) those normalized emission levels ( 41 ; 42 ), which were last assigned to the respective speed ranges. A method according to claim 1 or 2, characterized in that the exhaust gas component carbon dioxide and the state quantity of the vehicle ( 1 ) is a carbon dioxide mass flow and the reference value ( 43.1 ) a reference value ( 43.1 ) for the emission of carbon dioxide and the threshold ( 21 ) and the given mass ( 20 ) of the exhaust gas component in the calculations of the integrals of the mass flow ( 6 ) of the exhaust gas component are constant. Method according to one of the preceding claims, characterized in that a calculation of a first integral and a second integral of the mass flow ( 6 ) of the exhaust gas component are each divided and at least part of the calculation of the first integral and a part of the calculation of the second integral start and end at the same time and are performed with a single integrator. Method according to one of the preceding claims, characterized in that the exhaust gas component is carbon dioxide and in addition to the reference value ( 43.1 ) is a reference value for the emission of carbon dioxide ( 43.2 ) for an emission of nitrogen oxide in real time is determined by the following steps: - calculation of a respective corresponding integral of a mass flow ( 6 ) of nitric oxide to the respective integral of the mass flow ( 6 ) of carbon dioxide, the respective calculation of the corresponding integral of the mass flow ( 6 ) of nitrogen oxide at a same starting time as the calculation of the corresponding integral of the mass flow ( 6 ) of carbon dioxide is started and terminated at the same end time, - calculation of a respective corresponding normalized emission value for nitrogen oxide ( 42 ) each of an integral value of the integral of the mass flow ( 6 ) of nitrogen oxide and in each case the corresponding distance traveled by the vehicle ( 1 ) - Assignment of the respective standardized emission values for nitrogen oxide ( 42 ) to the first, second or third speed range from the detected corresponding corresponding average speeds ( 44 ), - determining the reference value ( 43.2 ) for the emission of nitrogen oxide from the normalized emission levels for nitrogen oxide ( 42 ), wherein at least three of the standardized emission values for nitrogen oxide ( 42 ), which have been assigned to the first, second and third speed ranges, respectively, and a weighting of the respective standardized emission values for nitrogen oxide ( 42 ) at least as a function of the corresponding corresponding standardized emission values for carbon dioxide ( 41 ), - comparing the reference value ( 43.2 ) for the emission of nitric oxide with a target value for emission of nitrogen oxide. Method according to one of the preceding claims, characterized in that the reference value ( 43.1 ; 43.2 ) for controlling the internal combustion engine ( 2 ) is used. Method according to one of the preceding claims, characterized in that the reference value ( 43.1 ; 43.2 ) for an application of the internal combustion engine ( 2 ) is used. Method according to one of the preceding claims, characterized in that the reference value ( 43.1 ; 43.2 ) for monitoring the internal combustion engine ( 2 ) is used. Method according to one of the preceding claims, characterized in that during a whole journey of the vehicle ( 1 ) the normalized emission values ( 41 ; 42 ) are assigned to the speed ranges and the reference value ( 43.1 ; 43.2 ) an exhaust gas behavior of the internal combustion engine ( 2 ) for the entire journey. Internal combustion engine ( 2 ) with a control device ( 3 ), which has at least one integrator, wherein the integrator one by means of the control unit ( 3 ) detected mass flow ( 6 ) an exhaust gas component of the internal combustion engine ( 2 ) and the control unit ( 3 ) has a non-transitory computer-readable storage medium with information stored thereon, which when executed by a processor of the controller ( 3 ) effect an implementation of the method according to claim 1.

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