DE10115968A1 - Process for heating a catalyst - Google Patents

Abstract

The invention relates to a method for heating at least one catalytic converter (16, 18) arranged in an exhaust system of an internal combustion engine (10), wherein in particular after an engine start (T¶0¶) of the internal combustion engine (10) at least temporarily an exhaust gas temperature and / or a catalyst temperature (T¶Kat¶) is raised by at least one motor measure. DOLLAR A It is provided that the warm-up operation is carried out with at least two parameter sets (PE, PT) for controlling the internal combustion engine (10), between which, depending on the operating data of the internal combustion engine (10) and / or the exhaust system, it is possible to switch gradually or smoothly , and at least one first parameter set (PE) is designed for low pollutant emissions (emission-optimized) and at least one second parameter set (PT) is designed for achieving high exhaust gas temperature and / or catalyst temperature (T¶Kat¶) (temperature-optimized).

Description

The invention relates to a method for heating at least one in an exhaust system an internal combustion engine arranged catalyst, especially after a Engine start, with the features mentioned in the preamble of claim 1.

Catalysts are used in exhaust systems of internal combustion engines in order to Conversion of pollutants in exhaust gases from the internal combustion engine into less to make environmentally relevant components. To keep them operational, catalysts must at least refer to a catalyst-specific light-off or Have warmed light-off temperature. Since the catalyst is especially after a Engine cold start of the internal combustion engine for a certain period of time Starting temperature does not usually have, the pollutants of the Exhaust gas largely unconverted to the atmosphere during this period. Different strategies are for accelerating a catalytic converter warm-up and for Known reduction in pollutant emissions during warm-up.

Small-volume pre-catalysts are often installed at a position close to the engine Exhaust system used. The pre-catalysts achieve because of their low thermal Mass and their location near the engine relatively quickly their light-off temperature and bridge thus a period of time until a large volume that is further downstream Main catalytic converter has reached its operating temperature.

It is also customary to have an ignition angle at which an ignition of an air-fuel mixture a cylinder occurs while warming up late with respect to one Ignition angle to adjust with maximum efficiency. Through this Ignition retard is reduced and the working efficiency of the combustion simultaneously increases an exhaust gas temperature. The process of late ignition takes place Limitation at ignition angles at which the internal combustion engine runs unevenly increases improperly or reliable ignition can no longer be guaranteed can. Other methods, such as late fuel injection after ignition before or after a burning, aim at the release of combustion energy directly on the catalytic converter when converting the non-burned in the cylinder  Fuel. Disadvantages of these processes are often increased soot formation and Problems of burning stability and the representation of stable engine torques under load.

Another method for increasing the exhaust gas temperature is opened by a so-called multiple injection, which has recently been described for direct-injection, spark-ignition internal combustion engines in which the fuel is injected directly into a combustion chamber of a cylinder by means of injection valves (WO 00/08328, EP 0 982 489 A2, WO 00/57045). A total amount of fuel to be supplied during a working cycle of a cylinder is divided into two portions and fed to a combustion chamber of the cylinder with two injection processes. A first, early injection (homogeneous injection) takes place during an intake stroke of the cylinder such that the amount of fuel injected at the subsequent ignition point has an at least largely homogeneous distribution in the combustion chamber. A second, late injection (stratified injection), on the other hand, is carried out during a subsequent compression stroke, in particular during the second half of the compression stroke, and leads to a so-called stratified charge, in which the injected fuel cloud concentrates essentially in the area around a spark plug of the cylinder. Thus, in multi-injection operation of the internal combustion engine, there is a mixed operation of stratified charge and homogeneous charge. The multi-injection mode leads to an increased exhaust gas temperature compared to pure homogeneous mode due to its special type of combustion process. In addition, there is another advantage of multiple injection in a reduced raw emission of nitrogen oxides NO _x and unburned hydrocarbons HC, which overall leads to a reduction in pollutant breakthrough during the warm-up phase.

Problematic with practically all heating measures compared to an operation with optimal Engine efficiency is an increased raw emission of pollutants due to the still not or only partially operational catalyst not be implemented.

The invention is therefore based on the object of a method for warming up a To provide catalyst that the fastest possible heating of the catalyst guaranteed at the same time the lowest possible pollutant emissions.

This object is achieved by a method with the features mentioned in claim 1 solved. Because the warm-up mode with at least two parameter sets for Control of the internal combustion engine is carried out between those in Dependence on operating data of the internal combustion engine and / or the exhaust system  can be switched gradually or smoothly, and at least a first one Parameter set is designed with a view to low pollutant emissions (emission-optimized) and at least a second parameter set with regard to a high one Exhaust gas temperature and / or catalyst temperature is designed (temperature-optimized), is the warm-up mode needs to a current operating point of the Internal combustion engine or the exhaust system adapted.

It is particularly provided that warm-up operation after the engine has started initially carried out essentially according to the emission-optimized parameter set becomes. Since in this first phase, due to the still low catalyst temperatures, the The catalyst system contains at least largely unconverted pollutants will go through lowering the raw emissions, especially of unburned ones Hydrocarbons HC, pollutant emissions significantly reduced. A later phase the warm-up operation then takes place essentially in accordance with the temperature-optimized Parameter set to - as soon as a certain catalyst temperature, especially in one first catalyst, is reached and there is a noticeable conversion rate - under Acceptance of a higher raw emission through a warming of the to achieve entire catalyst system or parts thereof.

The operating data of the internal combustion engine and / or the exhaust system, in their Dependence the gradual or continuous switching between the Parameter sets or between the corresponding operating modes, preferably include temperature data of the at least one catalyst or such allow conclusions to be drawn about the catalyst temperature. In particular, the Operating data the current catalyst temperature itself and / or a catalyst temperature at engine start and / or a dynamic of the catalyst temperature and / or a current one Engine temperature and / or an engine temperature at engine start. To determine the Catalyst temperature can also be a measured or appropriate Operating parameters of the internal combustion engine modeled exhaust gas temperature be used. The relevant operating data can also include, among other things Operating point, in particular an engine load and / or an engine speed, and / or one Internal resistance of a lambda probe connected downstream of the internal combustion engine and / or a time elapsed since engine start and / or a time passed after engine start Fuel quantity and / or engine revolutions and / or one since engine start Distance traveled by engine start and / or in the catalyst system since engine start heat quantity entered.  

According to an advantageous embodiment of the method, it is used for at least one Operating data, a threshold value is specified, if exceeded between the Parameter sets, especially between the emission-optimized and the temperature-optimized parameter set, is switched. For example, at Exceeding a certain catalyst temperature, in particular at least one zone a pre-catalyst close to the engine, while accepting an increased Raw emissions can be switched to the temperature-optimized operating mode. This temperature threshold should be dimensioned such that the catalyst is a at least extensive conversion of raw emissions in the temperature-optimized Mode can afford. In an alternative embodiment of the method, this input Step switchover by a smooth switchover between the parameter sets replaced. For this purpose, the parameter sets are weighted depending on the above Operating data and a control of the warm-up operation with parameters by Interpolation between the weighted parameter sets determined and continuously updated become. The weighting is preferably such that a weight of the emission-optimized parameter set is high at low catalyst temperatures and decreases with increasing catalyst temperatures. Because fuzzy logic because of the A multitude of criteria compared to classic processes simplify the application and bring about a reduction in the calculation effort in an engine control system for weighting and / or interpolation, the use of a fuzzy Logic method based method. In addition, this version can be used with flowing Switching the warm-up coordinated in more detail with an actual journey because all emission-relevant parameters are constantly taken into account. As a result can be even lower compared to the gradual changeover Total emissions can be achieved behind the catalyst system.

In the case of a spark-ignited, lean-burn internal combustion engine with is equipped with a direct injection system, the engine heating measure a multiple injection is particularly preferred, in which within one working cycle a cylinder performed at least two fuel injections into the cylinder be, a first injection during an intake stroke and a second Injection during a compression stroke, especially the second half of the Compression cycle takes place. In this context, it is particularly preferably provided that that the internal combustion engine is also stratified, so that during the second injection of the multiple injection fuel becomes one Ignition timing essentially in the form of a fuel cloud in the area of a spark plug of the cylinder concentrated. The formation of this stratified charge cloud can  advantageously by known design measures in the form of a wall guide and / or an air duct are supported. A wall-guided measure can for example in the form of a special design of a piston crown, in particular with Troughs. On the other hand, the air flow of the stratified charge cloud by generating certain air flow conditions in the combustion chamber of the cylinder, for example in the form of a so-called tumble or swirl flow. For this purpose, the arrangement of movable, preferably stepless or multi-stage movable charge movement flaps in the cylinder's air intake pipes direct the air flow. Preferably with the first injection (Homogeneous injection) a homogeneous, lean, even non-ignitable air-fuel Mixture generated, so that only with the second injection in the area of the spark plug ignitable mixture is formed. After ignition and burning of this mixture cloud the flame migrates into the homogeneous outer zones of the combustion chamber and burns there much slower because of the low fuel content. As a result, the efficiency decreases of the engine and a release of energy into the exhaust gas increases. A ratio of Fuel proportions of the two injections can range from 20 to 80% to 80 to 20% lie, with an average air-fuel ratio in the combustion chamber preferably between λ = 0.9 and 1.2.

The engine measure can also be an ignition angle adjustment, in particular in Towards a late firing angle, preferably multiple injection and late ignition can be used in combination.

In the case of a combination of multiple injection and late ignition, these include Parameter sets as essential control parameters are an ignition angle and / or a Injection angle of the second injection of the multiple injection and / or an air Fuel ratio and / or fuel shares of the first and second injection of the Multiple injection operation. Of course, the parameter sets can be more variable or constant parameters, such as an exhaust gas recirculation rate or a Injection pressure included. The emission-optimized parameter set preferably comprises a firing angle earlier than the temperature-optimized parameter set and / or an earlier injection angle of the second injection and / or a leaner air -Fuel ratio.

The principle of the method according to the invention is not based on late ignition or Multiple injection limited. Rather, the motor measure can be used to raise it the exhaust gas and / or the catalyst temperature comprise further methods, for example  post-injection of fuel into the cylinders after the ignition timing before or after the end of burning. Furthermore, exhaust gas afterburning is known, in which a Ignition of a mixture of rich exhaust gas and secondary air in the exhaust tract with or without additional ignition device takes place, or a speed increase in idle. moreover non-motor heating measures can also be carried out, especially one electric catalyst heating and / or a catalyst heating by means of a Brenner and / or a suitable transmission control, at which switching points to higher Speeds are shifted.

Further preferred refinements of the invention result from the others in the Characteristics mentioned subclaims.

The invention is described below in exemplary embodiments on the basis of the associated Drawings explained in more detail. Show it:

Fig. 1 shows schematically an arrangement of an internal combustion engine with a downstream exhaust system;

Fig. 2 is a time course of different parameters according to a first embodiment of the method according to the invention;

Fig. 3 is a bar graph of a cumulative HC raw emissions and a catalyst temperature according to different parameter sets for catalyst warm-up and

Fig. 4 shows a variation of various parameters of a second embodiment of the method according to.

Fig. 1 shows a spark-ignition lean-running internal combustion engine capable of 10, which comprises for example four cylinders 12. The internal combustion engine 10 has a direct injection system, not shown, via which fuel is injected directly into the cylinders 12 . An exhaust gas generated by the internal combustion engine 10 is passed through an exhaust duct 14 of an exhaust system and the catalytic converter system 16 , 18 arranged therein. The catalytic converter system comprises a small-volume pre-catalytic converter 16 arranged close to the engine and a main catalytic converter 18 , for example a NO _x storage catalytic converter, which is usually arranged at an underbody position. An air-fuel ratio λ supplied to the internal combustion engine 10 is regulated by measuring an oxygen concentration of the exhaust gas with the aid of a lambda probe 20 . A temperature sensor 22 , which is arranged downstream of the pre-catalytic converter 16 in the exhaust gas duct 14 , makes it possible to measure an exhaust gas temperature and thus draw conclusions about the temperature of the pre-catalytic converter and / or the main catalytic converter 16 , 18 . Alternatively, the temperature sensor 22 can also be arranged elsewhere, for example upstream or in the pre-catalytic converter 16 . Furthermore, the catalytic converter temperature T _{Kat can} also be calculated on the basis of suitable models based on current operating parameters of the internal combustion engine 10 . The signals provided by the sensors 20 , 22 and various operating parameters of the internal combustion engine 10 are transmitted to an engine control unit 24 , where they are evaluated and processed in accordance with stored algorithms and maps. Depending on these signals, the engine 10 is controlled by the engine control unit 24 , in particular the air-fuel ratio λ, an injection mode and the ignition.

If, for example, after a cold engine start with the aid of the temperature sensor 22 or arithmetically a temperature of the catalytic converter system, in particular the pre-catalytic converter 16 , is determined, which is below a light-off temperature necessary for a sufficient pollutant conversion, the engine control unit 24 directs various measures for raising the exhaust gas temperature and / or Catalyst temperature T _{Kat on} . The operation of the internal combustion engine 10 is preferably switched from single injection to multiple injection. In multiple injection operation, a first, early injection takes place preferably within the first half of an intake stroke of a cylinder 12 , so that the fuel supplied in this injection is essentially homogeneous in the combustion chamber distribution at a subsequent ignition point (homogeneous injection). A second, late fuel injection (stratified injection) takes place in particular in the second half of a compression stroke. Supported by wall and / or air-guiding measures, the fuel supplied in the stratified injection is essentially in the form of a stratified charge cloud in the area of a spark plug of a cylinder 12 at the time of ignition. As a further heating measure, an ignition angle is adjusted in the direction of a late ignition point in relation to an ignition point with the highest engine efficiency. Both the special combustion processes of the multiple injection mode and the spark ignition cause an increase in the exhaust gas temperature and thus an accelerated warm-up of the catalyst system 16 , 18 .

According to the present invention, there are at least two parameter sets in the engine control unit 24 , according to which the internal combustion engine 10 can be controlled while the catalytic converter system 16 , 18 is warming up. At least one parameter set is optimized with regard to a low raw emission from the internal combustion engine 10 , in particular from unburned hydrocarbons HC, while a second parameter set is designed with the greatest possible heating effect. The switchover between the individual parameter sets, which can take place in stages or smoothly, is carried out as a function of a large number of operating data of the internal combustion engine 10 and / or of the exhaust system, in particular of a temperature of the pre-catalyst 16 .

The course of different parameters during a warm-up of the catalyst system 16 , 18 according to a first embodiment of the method, in which the warm-up is carried out in two phases with two parameter sets PE, PT with a one-stage changeover, is shown in FIG. 2. Warm-up operation is initiated shortly after an engine start t _O at time t _B , for which purpose multi-injection and the retarding of the ignition angle are used as engine heating measures. In a first phase of warming up, the control of the internal combustion engine 10 takes place with parameters that are stored in the emission-optimized parameter set PE. The operating status or an activation of the parameter sets is shown in the upper part of FIG. 2. In studies on a stratified charge, spark-ignited internal combustion engine with direct injection and 2-liter displacement, which has an air and wall-guided combustion process, a parameter set PE with a low spark ignition, a relatively high lambda pilot control value and an early injection end has been found for raw emission-optimized operation Layer injection proved to be advantageous. In particular, an ignition angle α _Z of 0 to 20 ° after an upper ignition dead center ZOT, preferably of 10 ° after ZOT has proven itself (lower part of the figure). At the same time, one end of the stratified injection is preferably actuated with an injection angle α _EE of 100 to 40 ° before ZOT, in particular from 90 to 50 ° before ZOT, preferably from 60 ° before ZOT. The air-fuel ratio λ is preferably pre-controlled or regulated in this phase to 1.1 to 1.3, in particular to 1.2 (middle part of the figure). This low-emission operation is maintained while the parameters α _Z , α _EE, λ are kept constant until predetermined operating data of the internal combustion engine 10 or of the exhaust system reach predetermined threshold values. In particular, a minimum temperature of at least a first zone of the pre-catalytic converter 16 can be taken into account, which guarantees a certain minimum conversion performance. When the threshold value is reached, the changeover point t _U switches from the emission-optimized operating mode to the temperature-optimized operating mode with the parameter set PT. Because of the now available minimum conversion activity of the pre-catalytic converter 16, a certain increase in the raw emissions can be accepted. At the same time, the catalyst system 16 , 18 should be heated as quickly as possible by means of the highest possible heating potential. In the above example, a strong late ignition, a late end of the stratified injection and a lower lambda pilot control value have proven to be advantageous for this. In particular, an ignition angle α _Z between 15 and 45 ° according to ZOT, in particular at approximately 30 ° according to ZOT, and an injection end α _{EE of} the stratified injection in multiple injection operation from 60 to 20 ° before ZOT, in particular from 50 to 30 ° before ZOT, have proven successful , preferably from 40 ° before ZOT. An air-fuel ratio λ of between 1.0 and 1.2, preferably of about 1.1, is set. Since the optimal parameters vary greatly with the design of the internal combustion engine 10 , the values mentioned are to be understood as examples. The warm-up operation is ended at a time t _E , for example when the pre-catalytic converter 16 has at least approximately reached its full operational capability. At this point, the system switches back to a single injection mode and the retarded ignition timing is withdrawn. The air-fuel ratio λ is specified as a function of the current operating point, in this example λ = 1.

The effects of an operation of the internal combustion engine 10 on the basis of different parameter sets on a cumulative raw HC emission HC and on a temperature T _{Kat of} a pre-catalytic converter 16 arranged about 30 mm downstream of the internal combustion engine 10 are shown in FIG. 3. The measurement took place 12 seconds after a cold engine start at 20 ° C with a vehicle speed profile according to the new European standard driving cycle NEDC. The data on the left-hand side of the illustration were obtained using a conventional catalytic converter heating process with spark ignition at an ignition angle α _Z of 10 ° according to ZOT in single-injection mode and serve as a reference. The data in the middle and right part of the figure correspond to measurements with the emission-optimized parameter set PE with α _Z = 10 ° according to ZOT, α _EE = 60 ° before ZOT and λ = 1.2 or with the temperature-optimized parameter set PT with α _Z = 30 ° after ZOT, α _EE = 40 ° before ZOT and λ = 1.1. The left-hand columns each show the raw HC emissions accumulated more than 12 seconds after the engine was started, that is to say the HC emissions upstream of the catalyst system 16 , 18 , the raw HC emissions being normalized to one another in relation to the conventional operation with spark ignition PK. The right-hand columns each show the temperature T _{Kat of} the pre-catalytic converter 16 , which was determined using a temperature measuring point located approximately 20 mm downstream of a gas inlet surface. The comparison of the raw HC emissions of the different operating modes shows, on the one hand, that in the multiple injection mode PE, PT the raw HC emissions can be significantly reduced compared to the single injection mode PK, namely to about 80% in temperature-optimized mode with the parameter set PT and even to about 35% , if the parameters are designed with the lowest possible pollutant emissions (parameter set PE). On the other hand, in multi-injection operation, a higher heating output is generally achieved than with conventional spark ignition. While the measured catalytic converter temperature T _{Kat of} the pre-catalytic converter 16 is only 50 ° K 12 seconds after the engine is started, a catalytic converter temperature T _Kat of approximately 65 ° C is observed in the emission-optimized multiple injection mode PE and even 200 ° C in the temperature-optimized multiple injection mode PT. As a result, it can be determined that the multiple injection operation with late ignition is fundamentally superior to the single injection operation with late ignition in terms of both pollutant emission and heating effect. Furthermore, it becomes clear that in multi-injection operation with spark ignition, by appropriate design of the parameters with which the internal combustion engine 10 is controlled, dramatic effects with regard to the raw HC emission on the one hand and the heating effect on the other hand can be achieved. In this way, by specifying the respective parameter sets in a targeted manner, the raw HC emissions and thus the final HC emissions can be reduced compared to conventional processes and, at the same time, the catalyst system can be heated up more quickly.

FIG. 4 shows time profiles of the parameters during a warm-up according to a second advantageous embodiment of the method, in which a continuous changeover between the two parameter sets PE and PT takes place instead of the step-by-step changeover. In this case, depending on the operating _data already mentioned, in particular the catalyst temperature T _Kat , the parameter sets PE and PT are weighted and the internal combustion engine 10 is controlled with interpolated parameters. According to the example shown, the warm-up operation begins at time t _B in pure emission-optimized operation, that is to say with a 100% weight of the parameter set PE. As the warm-up continues, in particular when the catalyst temperature T _{Kat rises} , the emission-optimized operation loses weight in favor of the temperature-optimized operation. As a result, the ignition angle α _Z and injection angle α _{EE of} the layer injection are adjusted increasingly late. At the same time, the lambda control value λ decreases. Compared to the embodiment shown in FIG. 2, the smooth transition from emission-optimized to temperature-optimized operation has the advantage of taking the actual operating state of internal combustion engine 10 into account more precisely and thus enables a further reduction in emissions with rapid catalyst heating.

LIST OF REFERENCE NUMBERS

10

Internal combustion engine

12

cylinder

14

exhaust duct

16

precatalyzer

18

Main catalyst / NO _x

storage catalyst

20

lambda probe

22

temperature sensor

24

Engine control unit
α _Z

firing angle
α _EE

Controlling stratified injection
EE single injection
λ air-fuel ratio
ME multiple injection
PE emission-optimized parameter set
PK conventional parameter set
PT temperature-optimized parameter set
t time
t _O

Engine Start End
t _B

Start of warm-up phase
t _E

End of warm-up phase
t _U

switchover
T _cat

catalyst temperature
ZOT top ignition dead center

Claims (24)

1. Method for heating at least one catalytic converter ( 16 , 18 ) arranged in an exhaust system of an internal combustion engine ( 10 ), in particular after an engine start (t _O ) of the internal combustion engine ( 10 ) at least temporarily an exhaust gas temperature and / or a catalyst temperature (T _Kat ) is raised by at least one engine measure, characterized in that the warm-up operation is carried out with at least two parameter sets (PE, PT) for controlling the internal combustion engine ( 10 ), between which step by step depending on operating data of the internal combustion engine ( 10 ) and / or the exhaust system or can be switched smoothly, and at least one first parameter set (PE) is designed for low pollutant emissions (emission-optimized) and at least one second parameter set (PT) is designed for reaching a high exhaust gas temperature and / or catalyst temperature (T _Kat ) (temperate uroptimiert). 2. The method according to claim 1, characterized in that the emission-optimized parameter set (PE) is designed essentially for a low raw emission of the internal combustion engine ( 10 ) from unburned hydrocarbons (HC). 3. The method according to claim 1 or 2, characterized in that after the engine start (t _O ), the warm-up operation is first carried out essentially according to the emission-optimized parameter set (PE) and later essentially according to the temperature-optimized parameter set (PT). 4. The method according to any one of the preceding claims, characterized in that the operating data of the internal combustion engine ( 10 ) and / or the exhaust system, a current catalyst temperature (T _Kat ) and / or a catalyst temperature (T _Kat ) at engine start and / or a dynamics of the catalyst temperature (T _Kat ) and / or a current engine temperature and / or engine temperature when starting an engine. 5. The method according to any one of the preceding claims, characterized in that the operating data of the internal combustion engine ( 10 ) and / or the exhaust system, an engine operating point, in particular an engine load and / or an engine speed, and / or an internal resistance of a lambda sensor connected downstream of the internal combustion engine ( 10 ) ( 20 ) and / or a time elapsed since engine start (t) and / or a quantity of fuel passed through after engine start and / or engine revolutions since engine start and / or a distance traveled since engine start and / or heat quantity entered into the catalytic converter system since engine start. 6. The method according to any one of the preceding claims, characterized in that a threshold value is specified for at least one of the operating data and at Exceeding the threshold between the emission-optimized Parameter set (PE) and the temperature-optimized parameter set (PT) switched becomes. 7. The method according to any one of claims 1 to 7, characterized in that the Parameter sets (PE, PT) are weighted depending on the operating data and the Warm-up operation variable with between the weighted parameter sets (PE, PT) interpolated parameters is operated. 8. The method according to claim 8, characterized in that a weighting of the emission-optimized parameter set (PE) is high at low catalyst temperatures (T _Kat ) and decreases with increasing catalyst temperatures (T _Kat ). 9. The method according to claim 8 or 9, characterized in that for the weighting and / or interpolation a method based on a fuzzy logic method is applied. 10. The method according to any one of the preceding claims, characterized in that the internal combustion engine ( 10 ) is spark-ignition and has a direct injection and the engine measure comprises a multiple injection (ME), with at least one cycle ( 12 ) of the internal combustion engine ( 10 ) two fuel injections are carried out in the cylinder ( 12 ) and a first injection takes place during an intake stroke of the working cycle and a second injection occurs during a compression stroke. 11. The method according to claim 11, characterized in that the internal combustion engine ( 10 ) is stratified and a fuel injected during the second injection of the multiple injection (ME) concentrates at an ignition point essentially in the area of a spark plug of the cylinder ( 12 ). 12. The method according to any one of the preceding claims, characterized in that the engine measure comprises an ignition angle adjustment, in particular in the direction of a late ignition angle (α _Z ). 13. The method according to any one of claims 11 to 13, characterized in that the parameter sets (PE, PT) an ignition angle (α _Z ) and / or an injection angle (α _EE ) of the second injection of the multiple injection (ME) and / or an air - Fuel ratio (λ) and / or fuel shares of the first and the second injection of the multiple injection (ME) include. 14. The method according to any one of claims 11 to 14, characterized in that the emission-optimized parameter set (PE) comprises an earlier ignition angle (α _Z ) than the temperature-optimized parameter set (PT). 15. The method according to any one of claims 11 to 15, characterized in that the emission-optimized parameter set (PE) comprises an earlier injection angle (α _EE ) of the second injection than the temperature-optimized parameter set (PT). 16. The method according to any one of claims 11 to 16, characterized in that the emission-optimized parameter set (PE) a leaner air-fuel ratio (λ) includes as the temperature-optimized parameter set (PT). 17. The method according to any one of claims 11 to 17, characterized in that the ignition angle (α _Z ) of the emission-optimized parameter set (PE) is between 0 and 20 ° after an upper ignition dead center (ZOT), in particular 10 ° according to ZOT. 18. The method according to any one of claims 11 to 18, characterized in that the injection end (α _EE ) of the second injection of the emission-optimized parameter set (PE) 100 to 40 ° before ZOT, in particular 90 to 50 ° before ZOT, in particular 60 ° before ZOT , is. 19. The method according to any one of claims 11 to 19, characterized in that the Air-fuel ratio (λ) of the emission-optimized parameter set (PE) between 1.1 and 1.3, in particular 1.2.   20. The method according to any one of claims 11 to 20, characterized in that the ignition angle (α _Z ) of the temperature-optimized parameter set (PT) is between 15 and 45 ° after an upper ignition dead center (ZOT), in particular 30 ° according to ZOT. 21. The method according to any one of claims 11 to 21, characterized in that the injection end (α _EE ) of the second injection of the temperature-optimized parameter set (PT) 60 to 20 ° before ZOT, in particular 50 to 30 ° before ZOT, preferably 40 ° before ZOT , is. 22. The method according to any one of claims 11 to 22, characterized in that the Air-fuel ratio (λ) of the temperature-optimized parameter set (PT) between 1.0 and 1.2, in particular 1.1. 23. The method according to any one of the preceding claims, characterized in that the engine measure comprises a post-injection of fuel into the cylinders ( 12 ) after ignition before, during or after the end of combustion and / or an exhaust gas post-combustion and / or an idle speed increase. 24. The method according to any one of the preceding claims, characterized in that no motor heating measures are carried out during warm-up, in particular an electric catalyst heating and / or Catalyst heating by means of a burner and / or a suitable one Transmission control with shifting of switching points to higher speeds.