CN109236481B

CN109236481B - Method for heating at least one catalytic converter of an internal combustion engine having an odd number of cylinders

Info

Publication number: CN109236481B
Application number: CN201810751043.1A
Authority: CN
Inventors: M.克诺普; S.哈尔; J.舒尔策
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-07-11
Filing date: 2018-07-10
Publication date: 2022-06-24
Anticipated expiration: 2038-07-10
Also published as: CN109236481A; DE102017211850A1

Abstract

The invention relates to a method for heating at least one catalyst of an internal combustion engine (10) having an odd number of cylinders, wherein two successive cylinders form a pair in a predefinable ignition sequence, wherein one cylinder of the pair is operated at an air/fuel ratio (lambda) greater than one and the other cylinder of the pair is operated at an air/fuel ratio (lambda) less than one, wherein the overall air/fuel ratio (lambda) of the pair assumes a predefinable value.

Description

Method for heating at least one catalytic converter of an internal combustion engine having an odd number of cylinders

Technical Field

The invention relates to a method for heating at least one catalytic converter of an internal combustion engine having an odd number of cylinders. The invention also relates to a computer program which is set up to carry out one of the methods.

Background

Catalyst heating is currently carried out with various engine measures in order to bring the catalyst as quickly as possible into its exhaust-gas-optimum temperature window in order to minimize emissions and to ensure a high efficiency of the catalyst. In order to achieve an optimum operating point within the conversion window of the catalytic converter, for example also after the engine has started, further engine measures are taken in order to keep the catalytic converter warm. One of these measures is for example lambda separation. Here, the cylinders are operated alternately around a known factor lean (mager) and rich (fett).

DE 1320890B 4 discloses a method for heating at least one catalyst (36, 38) in the exhaust gas of a combustion motor (12) which is operated with external ignition and direct injection of fuel into the air charge of at least one combustion chamber (11), by alternately generating a lean combustion chamber charge and a rich combustion chamber charge in the at least one combustion chamber (11), wherein the combustion motor (12) is operated in a first operating mode with a stratified combustion chamber charge and in a second operating mode with a homogeneous combustion chamber charge, wherein the lean combustion chamber charge is generated in the first operating mode and the rich combustion chamber charge is generated in the second operating mode, and wherein the external ignition (65) of the rich combustion chamber charge is delayed compared to the external ignition (63) of the lean combustion chamber charge, the delay of the external ignition (65) is distributed in such a way that the same torque is obtained from the combustion of the lean combustion chamber charge and the combustion of the rich combustion chamber charge.

EP 0902172 a2 discloses a method for operating a multi-cylinder internal combustion engine having the function of direct injection of gasoline into the cylinders, in which method at least one cylinder is operated alternately from cycle to cycle at a lambda value greater than or less than or sometimes equal to 1.0 and at least one other cylinder is operated alternately from cycle to cycle at a lambda value less than or greater than or sometimes equal to 1.0 for the purpose of post-combustion of gasoline in an exhaust system. As a result, post-combustion can take place in the exhaust system of the internal combustion engine, which can be carried out without additional injection and ignition devices, without a secondary air pump and without expensive temperature-dependent regulation.

In engines with an odd number of cylinders, a fixed configuration of the air/fuel ratio λ per cycle change forcibly results in: due to the odd number of cylinders, a uniform distribution is not possible, so that an undesirably different torque occurs.

Due to the different air/fuel ratios λ and the unequal number mainly through the cylinders, the torque of the cylinders provided by the cylinders changes during the transition from normal operation without λ separation to operation with λ separation. Such a change can be felt by the driver.

Disclosure of Invention

Against this background, the object of the invention is to: optimal heating of at least one catalyst of an internal combustion engine having an odd number of cylinders is provided, wherein all cylinders are used for heating the catalyst.

The invention relates to a method and a device for heating at least one catalyst of an internal combustion engine having an odd number of cylinders, and a computer program on a storage medium for carrying out the method. Advantageous refinements are the subject of the preferred embodiments.

In a first aspect, the invention relates to a method for heating at least one catalyst of an internal combustion engine having an odd number of cylinders, wherein two successive cylinders form a pair in a predefinable ignition sequence, wherein one cylinder of the pair is operated at an air/fuel ratio greater than one and the other cylinder of the pair is operated at an air/fuel ratio smaller than one, wherein the overall air/fuel ratio of the pair assumes a predefinable value.

It is particularly advantageous in this case: by alternating operation of the cylinders with an air/fuel ratio greater than and less than one and by the pairing of two successive cylinders and by the predetermination of the air/fuel ratio for the pairing, good running smoothness of the internal combustion engine can be ensured, since the torque is distributed unequally to the heating process. Catalyst heating for internal combustion engines having an odd number of cylinders, in particular for internal combustion engines having three cylinders, is thus possible without the vehicle driver feeling an undesirable torque disturbance or the smoothness of operation of the internal combustion engine being disturbed. In other words, all cylinders participate in the heating process, in particular in the ignition sequence, so that the heating of the catalytic converter can be achieved more quickly.

Furthermore, it can be provided that the predeterminable value for the overall air/fuel ratio of the pair is one.

This is particularly advantageous when a three-way catalyst is used, since in this case a high conversion to harmful substances produced by the internal combustion engine can be ensured.

By alternating lean and rich operation of the cylinders: the exhaust gases of every two cylinders sum to give the desired air/fuel ratio and thus the best possible exhaust gas conversion.

On the other hand, the remaining cylinders in a combustion cycle and the cylinders from the subsequent combustion cycle form a pair, particularly in a cylinder ignition order that can be specified in advance. By forming the pair, uniform running smoothness of the internal combustion engine having an odd number of cylinders can be ensured.

Further, one cylinder of the pair operates at an air/fuel ratio less than one according to a first factor and the other cylinder of the pair operates at an air/fuel ratio greater than one according to a second factor.

The first factor is also limited by a comparison with a maximum predefinable threshold value, in particular by the air/fuel ratio.

This has particular advantages: the efficiency and the combustion limit can be observed by limiting the first factor. By taking into account the limited air/fuel ratio, it is prevented that: when the overall lambda changes, the lambda of the rich cylinder lies within a range predefined by the combustion limit, the ignition angle control range and sometimes for mobility reasons.

The second factor is limited by a comparison with a minimum threshold value that can be specified in advance, in particular by the air/fuel ratio.

By limiting the second factor, it is possible to comply with safe operation of the internal combustion engine and to comply with combustion limits. By taking into account the limited air/fuel ratio, it is prevented that: when the overall lambda changes, the lambda of the lean cylinder lies within a range predefined by the combustion limit, the ignition angle control range and sometimes for mobility reasons.

In one refinement, a value of the oxygen filling level for the at least one catalyst is determined, and the process of heating the at least one catalyst is started with an air/fuel ratio of less than one when the value of the oxygen filling level for the at least one catalyst exceeds the predeterminable threshold value.

If the at least one catalyst has stored sufficient oxygen, it is particularly advantageous: the process of catalyst heating (katilizen) begins with an air/fuel ratio of less than one because oxygen is already present as a reactive component for the heating process. Thereby preventing: the oxygen storage fill level of the catalyst goes to its limit and the exhaust conversion of the catalyst drops.

In a flexible refinement, the value of the oxygen filling level for the at least one catalyst is determined, and the process of heating the at least one catalyst is started with an air/fuel ratio greater than one when the value of the oxygen filling level for the at least one catalyst is below the predefinable threshold value.

This is advantageous because the heating of the catalyst can thus be carried out efficiently. This can prevent: the oxygen storage fill level of the catalyst goes to its limit and the exhaust conversion of the catalyst decreases.

Advantageously, the internal combustion engine is operated in a homogeneous operating state.

In a further aspect, the internal combustion engine can be a gasoline direct injection and/or Gas operated internal combustion engine, in particular an internal combustion engine operated with Liquefied Petroleum Gas (LPG-Liquefied Petroleum Gas) or with Compressed Natural Gas (CNG-Compressed Natural Gas).

In a further aspect, the invention relates to an apparatus, in particular a controller, and a computer program which are set up, in particular programmed, to carry out one of the methods. In a further aspect, the invention relates to a machine-readable storage medium on which the computer program is stored.

Drawings

The invention is further explained below with the aid of embodiments and with reference to the drawings. Wherein:

FIG. 1 shows a schematic diagram of an internal combustion engine with direct injection and exhaust, the exhaust having a catalyst;

FIG. 2 shows a flowchart of an example of a method for heating at least one catalyst of an internal combustion engine having an odd number of cylinders; and is

Fig. 3 shows two combustion cycles.

Detailed Description

Fig. 1 shows a schematic illustration of an internal combustion engine 10 with direct injection and an exhaust system with a catalytic converter. The internal combustion engine 10 has at least one combustion chamber 11, which is movably sealed by a piston 12. The change of the charge of the combustion chamber 11 is controlled by means of at least one inlet valve 6 and at least one outlet valve 7. The intake valve 6 is operated by the intake valve adjuster 4, and the exhaust valve 7 is operated by the exhaust valve adjuster 5. The intake valve adjuster 4 and the exhaust valve adjuster 5 can be realized not only by a camshaft as a mechanical adjuster, but also by an electrical or pneumatic adjuster.

The piston 12 draws air from an intake pipe 13 when the intake valve 6 is open. During the suction process and/or during the subsequent compression process, fuel is dosed directly into the combustion chamber 11 via the injection valve 8. The resulting combustible mixture is ignited by the spark plug 9 in the combustion chamber 11 (ignition from an external source).

When the exhaust valve 7 is opened, burned exhaust gas is discharged from the combustion chamber 11 to the exhaust device. The catalyst 18 is located downstream of the exhaust gas device, that is to say downstream of the exhaust gas line 17. The catalyst 18 may for example consist of three

support structures

20, 21 and 22, which differ in their catalytic coating. The catalytic converter 18 is preferably designed as a three-way catalytic converter and is regulated when the air/fuel ratio λ is equal to one. Alternatively or additionally, a plurality of catalytic converters can also be arranged in series from front to back or parallel to one another. When λ is equal to one, the internal combustion engine 10 is operated alternately with an oxygen excess and an oxygen deficiency, the cycle time of the rich-lean transition lying in the second range. In this case, the catalyst 18 stores oxygen and nitrogen during the oxygen-rich period, and catalytically reacts the oxygen and nitrogen with hydrocarbons and carbon monoxide contained later in the exhaust gas to produce carbon dioxide, water, and nitrogen during the oxygen-poor period. In this case also referred to as storage catalyst 18.

If, on the other hand, the internal combustion engine 10 is operated for a longer time with a lean mixture, that is to say with an excess of oxygen, the increasingly emitted nitrogen oxides are absorbed by the catalytic coating of the

support structures

20, 21 and 22 in the catalytic converter 18 and stored in the form of nitrate nitrogen (stickstoffnitanten).

This nitrate nitrogen is decomposed again by the short-term operation of the internal combustion engine 10 with a rich mixture. In contrast to the λ =1 regulation, the lean phase and the rich phase, with which the operation of the catalyst 18 is not approximately symmetrical, are utilized. The catalyst 18 can store oxygen and nitrogen oxides for a period of time of the order of minutes and release them again in converted form over a period of time of the order of seconds. In this way, the internal combustion engine 10 can be operated lean in total, while nitrogen oxides increasingly emitted in lean operation do not reach the environment in greater amounts.

Alternatively, the catalyst 18 may also be a particle catalyst or a three-way catalyst.

The control of the internal combustion engine 10 is effected by a control unit 100 which processes at least the signals of the air mass flow meter 1, the signals of the rotational speed sensor 15 interacting with the sensor wheel 14 and the signals of the driver request transmitter 24. Furthermore, the control unit 100 can be supplied with signals from the first exhaust gas sensor 23, signals from the second exhaust gas sensor 19 and further signals, not shown, from sensors for pressure and/or temperature in the region of the internal combustion engine 10 or the exhaust system. From these and, if appropriate, further input signals, the controller 100 forms control signals with which the internal combustion engine 10 can be operated in accordance with the driver's expectations and/or in accordance with preprogrammed requirements.

The filling quantity of the combustion chamber 11 can thus be adjusted in homogeneous operation of the internal combustion engine 10, for example, by means of the position of the throttle valve 2, which is actuated by the throttle actuator 3. In homogeneous operation, the torque produced by the internal combustion engine 10 is substantially determined by the mass of the combustion chamber charge and the selected ignition timing. In stratified operation, the internal combustion engine 10 operates relatively largely without restriction with the open throttle 2 and the maximum air-utilizing combustion chamber charge of the combustion chamber 11. In this case, the torque generated by the internal combustion engine 10 is essentially determined by the mass of fuel injected and the ignition time.

Fig. 2 shows a flowchart of a method for heating at least one catalyst 18 of an internal combustion engine 10 having an odd number of cylinders. The method may also be used with an internal combustion engine 10 having an odd number of cylinders with more than three cylinders (5, 7, 9 … cylinders). The internal combustion engine 10 can furthermore be a gas-operated internal combustion engine 10, for example the following: the internal combustion engine operates with Liquefied Petroleum Gas (LPG-Liquefied Petroleum Gas) or Compressed Natural Gas (CNG-Compressed Natural Gas) or as a mixture with gasoline and Gas.

The following describes an embodiment for an internal combustion engine 10 having three cylinders.

In a first step 500, the temperature of the catalyst 18 is determined by means of a temperature sensor or a temperature model. If the determined temperature value of the catalytic converter 18 is below a first predefinable threshold value (for example 500 ℃) and above a second predefinable threshold value (for example between 200 and 250 ℃), the catalytic converter 18 must be heated in order to reach a minimum temperature at which it can guarantee its catalytic effect. Preferably, the operating temperature for the catalyst lies at about 500 ℃.

As an alternative or in addition to the criterion for determining whether the catalytic converter 18 has to be heated, an evaluation of the operating state of the internal combustion engine 10, for example, a cold start of the internal combustion engine 10, may be carried out. Such an operating state of the internal combustion engine 10 can be realized, for example, by information stored in the controller 100.

The heating of the catalytic converter 18 is effected by post-combustion of the fuel in the exhaust system.

In this case, a lambda separation for the cylinders of the internal combustion engine 10 is carried out. That is, the cylinders of the internal combustion engine 10 are alternately operated lean or rich, that is to say with an air/fuel ratio λ greater or less than one, around a known factor.

The distribution of the different air/fuel ratios λ in one combustion cycle leads to an uneven distribution over the cylinders present, which is mandatory due to the odd number of cylinders. The "one combustion cycle" is preferably understood as follows: each cylinder is operated once in a predefinable firing sequence, in particular for 4-stroke or 2-stroke operation.

For an internal combustion engine 10 having three cylinders, during a combustion cycle, two cylinders are operated at an air/fuel ratio λ greater than one and one cylinder is operated at an air/fuel ratio λ less than one or vice versa.

If the temperature of the catalytic converter 18 lies above a first predeterminable threshold value and below a second predeterminable threshold value, the process continues to the preceding step 500.

If in step 500: if a heating process of the catalytic converter 18 is required, then in step 510 different allocations of the air/fuel ratio λ for the three cylinders are required. This process is also referred to as lambda separation.

The air/fuel ratio lambda is distributed essentially as a function of the current operating parameters of the internal combustion engine 10. The operating parameters that have a great influence on the air/fuel ratio λ and the distribution of the air/fuel ratio λ are, for example: the rotational speed and torque of internal combustion engine 10 and the difference between the target catalyst temperature, which can be specified, and the current temperature of catalyst 18.

In step 510, the allocation for the odd number of cylinders now proceeds as follows. Starting with a predefinable ignition sequence, in particular a repeating ignition sequence, for each two cylinders a pair is formed, wherein one cylinder of the pair is operated with an air/fuel ratio lambda greater than one and the other cylinder of the pair is operated with an air/fuel ratio lambda less than one, such that the overall air/fuel ratio lambda is_gesIn particular, a predefinable, in particular one, value is obtained on average over the cylinder pair.

In fig. 3, a total of two combustion cycles (a; B) are shown. A possible ignition sequence for the first combustion cycle (a) starts with cylinder 1 and then follows

cylinders

2 and 3. The second combustion cycle B then begins again with cylinder 1, followed by

cylinders

2 and 3, and so on.

Based on the air/fuel ratio λ for the cylinder 1 adjusted in the first combustion cycle a, i.e. with an air/fuel ratio λ greater or less than one, the air/fuel ratio λ for the following cylinder in the ignition sequence is determined such that the cylinder is always operated with an alternating air/fuel ratio λ greater or less than one.

From one combustion cycle to the next, the air/fuel ratio lambda for each cylinder is alternated.

That is, a cylinder operating at an air/fuel ratio λ greater than one is operating at an air/fuel ratio λ less than one in the following combustion cycle and vice versa.

In the example of fig. 3, the first cylinder 1 of the firing sequence is operated at an air/fuel ratio λ greater than one. This yields: the cylinder 2 is operated with an air/fuel ratio lambda smaller than one. The cylinder 3 is then again operated at an air/fuel ratio lambda greater than one, and so on.

For a unique combustion cycle, it is possible to simply identify: such operation of the

cylinders

1, 2 and 3 causes unevenness in the air/fuel ratio λ.

This unevenness is then eliminated: two successive cylinders form a pair in a predefinable ignition sequence, so that the overall air/fuel ratio lambda is_gesIn particular, a predefinable, in particular one, value is obtained on average over the cylinder pair. In combustion cycle A, cylinder 1 and cylinder 2 form a first pair 70. Cylinder 3 in the first combustion cycle a then forms a second pair 80 with cylinder 1 from combustion cycle B, followed by a third pair 90 consisting of cylinder 2 and cylinder 3 in the second combustion cycle B. It can be easily understood that: each cylinder of internal combustion engine 10 is alternately operated at an air/fuel ratio λ that is greater than or less than one from one combustion cycle to the next.

Such repeated shifting of the air/fuel ratio λ by cylinders at air/fuel ratios λ greater than and less than one and the pairwise allocation of cylinders may ensure good running smoothness for an internal combustion engine 10 having an odd number of cylinders, so that the different torques are distributed uniformly and almost imperceptibly. Furthermore, the conversion of the exhaust gas is improved.

The use of this method is suitable primarily for homogeneous operation of the internal combustion engine 10, so that the air/fuel ratio λ preferably varies between 0.8 and 1.2, i.e. operation with an air/fuel ratio λ close to one.

Preferably, the first cylinder starts with a rich air/fuel ratio λ, that is to say with an air/fuel ratio λ which is smaller than one, after activation of the heating process of the catalytic converter 18.

The lambda separation for the cylinders is regulated by a characteristic map which determines a separation factor as a function of, for example, the rotational speed and/or the torque of internal combustion engine 10 and/or the current temperature regulation for catalytic converter 18.

The separation factor is calculated here for a cylinder pair as follows:

（1）

（2）

（3）

wherein λ_gesamtAn air/fuel ratio, faktor, for the cylinder pair is described_{Rich oil}Factors for cylinders operating at air/fuel ratios less than one are described, and faktor_{Lean oil}A factor is described for a cylinder operating at an air/fuel ratio greater than one. Preferably, the factor is always determined by the control unit 100, starting from a cylinder which is operated rich.

The faktor_{Lean oil}It is described herein that a factor is utilized that the air/fuel ratio λ is greater than one, and faktor_{Rich oil}A factor is described that utilizes an air/fuel ratio lambda less than one. Alternatively or additionallyAdditionally, in step 520, the two factors faktor_{Rich in oil}And faktor_{Lean oil}It is additionally possible to limit the current by comparing the current value with a threshold value.

If the faktor_{Rich oil}If a predefinable threshold value is exceeded, it can be predefined, for example, for faktor_{Rich oil}A maximum substitute value that can be specified beforehand, for example, a maximum value of 0.8 of the air/fuel ratio λ is obtained. In effectively limiting faktor_{Rich oil}Just, faktor_{Lean oil}The matching must be performed identically to equation (2).

If the faktor_{Lean oil}If the threshold value is lower than a predefinable threshold value, it can be predefined, for example, for faktor_{Lean oil}The smallest possible substitute value of (a) can be specified in advance, for example, a minimum value of 1.1 or 1.2 (for CNG) for the air/fuel ratio λ is obtained.

In effectively limiting faktor_{Lean oil}Just, faktor_{Rich oil}The matching must be performed identically to equation (2).

The limitation of the factor for the air/fuel ratio λ to be set yields additional safety, since the combustion limit of the cylinder can be monitored and too little injection time for combustion can be prevented, so that the flexibility of the internal combustion engine 10 can be ensured.

Alternatively or additionally, in step 530 it may be determined by means of a model determined on controller 100 for the oxygen load of catalyst 18: the cylinder at the beginning of the heating process of catalyst 18 should be operated at an air/fuel ratio greater or less than one.

For this purpose, the actual value of the oxygen load for the catalytic converter 18 is determined in the control unit 100.

If the actual value of the oxygen load for the catalytic converter 18 exceeds a predefinable threshold value, the catalytic converter 18 has stored a sufficient amount of oxygen for the heating process, so that the heating process can start with rich combustion, that is to say with an air/fuel ratio λ which is smaller than one.

If the actual value of the oxygen load for the catalyst 18 is below what can be specified in advanceAt a certain threshold value, the catalytic converter 18 has stored an oxygen quantity or not so far that the heating process starts with lean combustion, i.e. with an air/fuel ratio λ greater than one, that the catalytic converter 18 is initially supplied with oxygen in order to enable a chemical reaction which proceeds exothermically as quickly as possible. The target fuel quantity for the current cylinder is then determined by the controller 100 in step 540 and then multiplied by a predefined separation factor for that cylinder. If the cylinder should be operated at an air/fuel ratio greater than one, then the faktor is used_{Lean oil}. If the current cylinder is operating at an air/fuel ratio less than one, then the factor faktor is used_{Rich oil}。

The other cylinder of the pair is then operated by the factor determined for this cylinder, so that the overall air/fuel ratio λ_gesIn particular, a predefinable value, in particular one, is obtained on average over the cylinder pair.

The currently determined temperature of catalyst 18 may then be compared to the target catalyst temperature to be reached. If the current temperature of the catalyst 18 is below the target catalyst temperature, heating of the catalyst 18 continues.

If the current temperature of catalyst 18 is greater than or equal to the target catalyst temperature, catalyst heating is complete and may continue in step 500.

Claims

1. Method for heating at least one catalyst of an internal combustion engine (10) having an odd number of cylinders, characterized in that two successive cylinders form a pair in a predefinable ignition sequence, wherein one cylinder of the pair is operated at an air/fuel ratio (λ) greater than one and the other cylinder of the pair is operated at an air/fuel ratio (λ) smaller than one, wherein the overall air/fuel ratio (λ) of the pair_ges) The remaining cylinders in the combustion cycle and the cylinders from the subsequent combustion cycle are paired in a cylinder firing order that can be specified in advance.

2. Method according to claim 1, characterized in that the air/fuel ratio (λ) for the whole of the pair_ges) Is one.

3. A method according to claim 1 or 2, characterized in that one cylinder of the pair is according to a first factor (faktor)_{Rich oil}) Operating with an air/fuel ratio (λ) less than one and the other cylinder of the pair being operated according to a second factor (faktor)_{Lean oil}) Operating at an air/fuel ratio (λ) greater than one.

4. A method according to claim 3, characterized in that said first factor (faktor)_{Rich in oil}) The limitation is performed by comparison with a maximum threshold value that can be predetermined.

5. A method according to claim 3, characterized in that the second factor (faktor)_{Lean oil}) The limitation is performed based on a comparison with a minimum threshold value that can be predefined.

6. Method according to claim 1 or 2, characterized in that a value for the oxygen filling level for at least one catalyst is determined and the process of heating up of the at least one catalyst (18) is started with an air/fuel ratio (λ) smaller than unity when the value for the oxygen filling level for the at least one catalyst (18) exceeds a predefinable threshold value.

7. Method according to claim 1 or 2, characterized in that a value for the oxygen filling level for at least one catalyst is determined and the process of heating of the at least one catalyst (18) is started with an air/fuel ratio (λ) greater than one when the value for the oxygen filling level for the at least one catalyst (18) is below a predefinable threshold value.

8. Method according to claim 1 or 2, characterized in that the internal combustion engine (10) is operated in a homogeneous operating state.

9. Method according to claim 1 or 2, characterized in that the internal combustion engine (10) is a gasoline direct injection and/or gas operated internal combustion engine (10).

10. The method according to claim 4, characterized in that the first factor (faktor)_{Rich oil}) The limitation is performed by the air/fuel ratio (λ).

11. The method according to claim 5, characterized in that the second factor (faktor)_{Lean oil}) The limitation is performed by the air/fuel ratio (λ).

12. Method according to claim 9, characterized in that the internal combustion engine (10) is an internal combustion engine (10) running on liquefied petroleum gas or on compressed natural gas.

13. Electronic storage medium having a computer program which is set up for carrying out the method according to any one of claims 1 to 12.

14. Controller (100) set up for implementing the method according to any one of claims 1 to 12.