Method for controlling an internal combustion engine, control device, internal combustion engine unit and motor vehicle

Abstract

Method for controlling an internal combustion engine comprising a crankshaft (1), an intake valve, and a charge air compressor for pre-compressing charge air, wherein, during a charging stroke, the intake valve closes from a top dead center position (TDC, 0°) of the crankshaft (1) and in the direction of rotation (2) of the crankshaft (1), measured: - in a first operating mode (B1) at a first crankshaft angle (CW1) at a bottom dead center position (BDC, 180°) of the crankshaft (1); or - in a second operating mode (B2) at a second crankshaft angle (CW2) that is smaller than the first crankshaft angle (CW1) before the bottom dead center position (BDC, 180°); or - in a third operating mode (B3) at a third crankshaft angle (CW3) that is smaller than the second crankshaft angle (CW2) before the bottom dead center position (BDC, 180°), wherein the internal combustion engine - in the first operating mode (B1) is operatedif a first operating criterion is met, which is deemed to be met if one or more of the following first sub-criteria are met, namely if: - a current charge air pressure (pL) has a value that is derived from a first predetermined charge air pressure value range, which includes values ​​from zero up to and including a first predetermined limit charge air pressure (GpL), and / or - a current load of the internal combustion engine has a value that is derived from a first predetermined load value range, which includes values ​​from zero up to and including a first predetermined limit load value, and / or - a current gear ratio of a transmission coupled to the internal combustion engine has a value that is derived from a first predetermined gear ratio value range, which includes values ​​from zero up to and including a first predetermined limit gear ratio value.and / or - a current driving speed of a motor vehicle that has an internal combustion engine as its drive motor, has a value derived from a first predetermined speed value range, which includes values ​​from zero up to and including a first predetermined limit speed value, and / or - a current operating duration during which the internal combustion engine was last operated continuously in the first operating mode, has a value derived from a first predetermined time value range, which includes values ​​from zero up to and including a first predetermined limit operating duration value, and / or - an exhaust gas temperature is determined at an exhaust gas tract point of the internal combustion engine, the value of which is derived from a first predetermined exhaust gas temperature value range, which includes values ​​from zero up to and including a first predetermined limit exhaust gas temperature value,- is switched from the first operating mode (B1) to the second operating mode (B2) when a second operating criterion is met, - is switched from the second operating mode (B2) to the third operating mode (B3) when a third operating criterion is met.

Description

The present invention relates to a method for controlling an internal combustion engine, a control device configured to carry out the method or to control the internal combustion engine, an internal combustion engine unit comprising the control device, and a motor vehicle comprising such an internal combustion engine unit. There is a general need to minimize pollutant emissions from internal combustion engines throughout their entire operation, i.e., in all operating conditions, and to create means to operate internal combustion engines with ever lower emissions. Current efforts to achieve this aim include ensuring that the combustion process in the combustion chambers of the respective internal combustion engine always proceeds with a stoichiometric fuel-air ratio λ = 1. Furthermore, it is known – for example, from DE 44 80 333 T1, DE 603 ​​01 093 T2, or EP 3 620 635 A1 – to control an intake valve train in such a way that the corresponding intake valve is completely closed during a charging stroke (i.e., well before the associated connecting rod journal of a crankshaft of the internal combustion engine reaches its bottom dead center).DE 699 15 093 T2 discloses an internal combustion engine whose intake valve is adjusted such that, with increasing engine speed, it closes at an increasingly longer time interval from the moment the piston reaches bottom dead center. This reduces the fill level of the corresponding combustion chamber for a given compression ratio. Advantages include improved utilization of the expansion energy during the power stroke and consequently an increase in thermodynamic efficiency, reduced knocking tendency, the possibility of advancing the ignition timing at full load, and a reduced exhaust gas temperature. To compensate for the performance disadvantage resulting from the application of this principle (known to those skilled in internal combustion engines as the Miller cycle), charge air compressors (e.g., exhaust gas turbochargers, compressors, etc.) are used.) used, which require higher charge air pressures to be provided compared to conventionally operated internal combustion engines with charge air charging. The Miller cycle is used in modern internal combustion engines as soon as the engine speed, load, and charge air pressure allow for its use. This cools the exhaust gas early and efficiently, preventing predefined temperature limits of exhaust gas-contacting engine components and their peripherals from being exceeded. However, such early activation of the Miller cycle simultaneously leads to increased stress on engine components, particularly charge air compressors, even if the exhaust gas temperature would be uncritical without the Miller cycle's cooling effect.Therefore, there is a conflict of objectives between the desire to achieve the advantages of the Miller principle and the increased stress on components, especially charge air compressors, of the internal combustion engine when the Miller principle is applied. The purpose of the invention is to operate an internal combustion engine in a particularly efficient and low-emission manner. This problem is solved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and possible embodiments set forth in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, across categories and embodiments as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the dependent claims. In operation, an internal combustion engine emits exhaust gases. Temperature limits are specified to protect components of an internal combustion engine, or its peripheral components and / or assemblies, that come into contact with the exhaust gases. The invention is based on the consideration that, under average overall use of the internal combustion engine – for example, during use of a motor vehicle containing the internal combustion engine by an end user – temperatures exceeding or approaching the specified temperature limits are extremely rare.In order to at least mitigate the conflict of objectives described at the beginning, between the endeavor to efficiently exploit the advantages of the Miller principle and the increased component stress on the components, in particular a charge air compressor, of the internal combustion engine, the inventive method for controlling the internal combustion engine is proposed. Furthermore, the invention proposes a control device, for example an engine control unit, for an internal combustion engine, wherein the control device is configured to execute the method or to control the internal combustion engine according to the method. The invention further proposes an internal combustion engine unit comprising the internal combustion engine and the control device. The control device and the internal combustion engine are coupled or can be coupled to each other such that control signals provided by the control device result in an action by the internal combustion engine. The invention further proposes a motor vehicle comprising the internal combustion engine of the internal combustion engine unit as a drive motor.In its intended installation position, the internal combustion engine forms an integral part of the motor vehicle, with a crankshaft of the internal combustion engine and a wheel of the motor vehicle being mechanically coupled or connectable via one or more transmissions for the transmission of power / torque. Alternatively or additionally, the internal combustion engine serves as a drive element for an electric generator, which is coupled or connectable to an electric drive motor, with a rotor of the electric drive motor being directly or via one or more transmissions coupled or connectable to the wheel for the transmission of power / torque. Accordingly, the motor vehicle can be a purely internal combustion engine-powered vehicle or a hybrid-electric vehicle. The inventive method for controlling the internal combustion engine can be a computer-implemented method. In this case, the control unit is configured to execute the method. Furthermore, the invention proposes a computer program which, upon execution of its program commands by the control unit, causes the control unit to execute the method and consequently provide control signals for the internal combustion engine. The invention also proposes a computer-readable storage medium on which the computer program is stored. The internal combustion engine is a four-stroke reciprocating engine and comprises a crankshaft, a combustion chamber, and an intake valve associated with the combustion chamber. Furthermore, the internal combustion engine includes an intercooler for pre-compressing intake air. The intercooler consists of a compressor unit. This compressor unit is, in particular, an exhaust gas turbocharger or a compressor driven mechanically by the crankshaft and / or electrically; combinations of two or more compressors—especially of different types—are conceivable. Other components required for a functioning internal combustion engine, as well as possible designs—especially with two or more combustion chambers, each with two or more intake valves, etc.—are described below.These terms are familiar to those skilled in the art, which is why they are only discussed here to the extent necessary for the description. For the sake of simplicity, reference is made here only to a combustion chamber with its associated intake valve. When it is stated here that the intake valve is completely closed, this means that an intake valve seat of the combustion chamber is completely blocked against the flow of any fluid (e.g., air, etc.) by the intake valve body of the intake valve. If there are two or more intake valves per combustion chamber, the statement that the intake valve is completely closed means that all intake valve seats of the combustion chamber are completely blocked against the flow of any fluid. In this method, the intake valve train of the internal combustion engine is controlled such that, during a charging stroke occurring every two full crankshaft revolutions, the intake valve is fully closed at different crankshaft angles during the engine's normal operating direction, depending on the currently active operating mode. In other words, during each charging stroke, further movement of the intake valve body towards the closed position becomes impossible sooner or later, depending on the operating mode, because the intake valve body is already fully seated in the intake valve seat at the corresponding crankshaft angle, completely blocking airflow. The intake valve train can, for example, include a camshaft and / or a valve-specific linear actuator.In any case, the intake valve train is designed to adjust the timing of the intake valve, that is, to set an intake valve spread angle (described here in relation to a top dead center position of the crankshaft). In the first operating mode, the intake valve is actuated by the intake valve train in such a way that, during a charging stroke of the internal combustion engine, the intake valve closes completely at a first crankshaft angle KW1 (measured from the crankshaft's top dead center position in the direction of power rotation) and is fully closed at the crankshaft's bottom dead center position. In this first operating mode, the adjustment of the intake valve to its closed position is fully completed at bottom dead center, i.e., closer to bottom dead center than in the other two operating modes. In the second operating mode, the intake valve is actuated by the intake valve train in such a way that, during the charging stroke, the intake valve closes completely at a second crankshaft angle KW2 (measured from the crankshaft's top dead center position in the direction of power rotation).In this mode, the second crankshaft angle (KW2) is smaller than the first crankshaft angle (KW1); the adjustment of the intake valve to its closed position is completed closer to top dead center (i.e., earlier) than in the first operating mode. In a third operating mode, the intake valve is actuated by the intake valve train in such a way that, during the charging stroke, the intake valve closes completely at a third crankshaft angle (KW3) (measured from the crankshaft's top dead center in the direction of rotation). Here, the third crankshaft angle (KW3) is smaller than the second crankshaft angle (KW2); the adjustment of the intake valve to its closed position is therefore completed even closer to top dead center (i.e., even earlier) than in the second operating mode. The respective crankshaft angles KW1, KW2, KW3 are, in particular, angle values ​​derived from one of the crankshaft angle ranges [KW1], [KW2], [KW3] belonging to the corresponding operating mode. All angle values ​​of the first crankshaft angle range [KW1] are greater than all angle values ​​of the second and third crankshaft angle ranges [KW2], [KW3], with all angles of the second crankshaft angle range [KW2] being greater than all angle values ​​of the third crankshaft angle range [KW3]; the following holds true. Thus, the closing of the intake valve is completely completed in the first operating mode at the first crankshaft angle KW1 originating from the first crankshaft angle range [KW1], in the second operating mode at the second crankshaft angle KW2 originating from the second crankshaft angle range [KW2], and in the third operating mode at the third crankshaft angle KW3 originating from the third crankshaft angle range [KW3]. In this process, the internal combustion engine is further controlled such that it operates in the first operating mode if and as long as a first operating criterion is met. The first operating criterion is met if one or more of the sub-criteria described below are fulfilled. For example, the first operating criterion is met if the charge air flowing into the combustion chamber during the charging stroke has a charge air pressure whose value is derived from a first predefined charge air pressure range, which includes values ​​from zero up to and including a first predefined limit charge air pressure. Accordingly, the internal combustion engine operates in the first operating mode, for example, if and as long as the charge air is compressed by the charge air compressor to no more than the first predefined limit charge air pressure.The current boost pressure is determined, and if its value lies within the first predefined boost pressure range, the internal combustion engine—since the first sub-criterion relating to boost pressure is met—continues to operate in the first operating mode. The first predefined boost pressure limit characterizes, for example, a boost pressure at which the internal combustion engine provides the maximum possible torque for which it is designed. This means that, according to the procedure, the internal combustion engine operates in the first operating mode, in which the intake valve is fully closed at the first crankshaft angle (KW1) until the engine provides the maximum possible torque. This allows the vehicle to receive its full torque particularly quickly.Because the lower the charge air pressure, the better the responsiveness, meaning the more dynamic the driving experience of the vehicle feels to a user or driver. The first operating criterion is also met if the current load of the internal combustion engine has a value that falls within a first predefined load value range, which includes values ​​from zero up to and including a first predefined limit load value. The internal combustion engine will therefore continue to operate in the first operating mode if the load-related sub-criterion is met. For this purpose, the current load is determined. If the corresponding load value lies within the first predefined load value range, the first load-related sub-criterion is met. The first operating criterion is also met if the current gear ratio of a transmission coupled to the internal combustion engine has a value that falls within a first predefined range of gear ratio values, encompassing values ​​from zero up to and including a first predefined limit value. Thus, the currently engaged and / or coupled gear ratio is determined, and if the corresponding gear ratio value lies within the first predefined range, the first sub-criterion relating to the gear ratio is met, and the internal combustion engine continues to operate in the first operating mode. Furthermore, the first operating criterion is met if the current speed of a motor vehicle powered by an internal combustion engine falls within a predefined speed range, encompassing values ​​from zero up to and including a predefined limit speed. In other words, the vehicle's current speed is determined. If the corresponding speed value lies within this predefined speed range, the internal combustion engine continues to operate in the first operating mode, as the first sub-criterion relating to the vehicle speed is fulfilled. Furthermore, the first operating criterion is met if the current operating time, during which the internal combustion engine was last operated continuously in the first operating mode, has a value that falls within a first predefined time value range, encompassing values ​​from zero up to and including a first predefined limit operating time value. In other words, the system determines how long the internal combustion engine was last operated continuously in the first operating mode. If this time lies within the first predefined time value range, the first sub-criterion concerning operating time is met, and the internal combustion engine continues to operate in the first operating mode. The first operating criterion is also met if an exhaust gas temperature is determined at an exhaust gas tract point of the internal combustion engine, the value of which comes from a first predefined exhaust gas temperature range encompassing values ​​from zero up to and including a first predefined limit exhaust gas temperature value. The internal combustion engine therefore continues to operate in the first operating mode if the first sub-criterion concerning the exhaust gas temperature is met. For this purpose, the current exhaust gas temperature at the corresponding exhaust gas tract point is determined. If the corresponding exhaust gas temperature value lies within the first predefined exhaust gas temperature range, the first sub-criterion concerning the exhaust gas temperature is met. One, some, or all of the values ​​described herein (including the crankshaft speed described below) can be modeled, for example, by means of the engine control unit and / or another control unit (such as a transmission control unit, etc.). Alternatively or additionally, one, some, or all of the aforementioned values ​​can be measured, for example, by means of a suitably configured and positioned sensor. For example, the exhaust gas temperature can be determined by modeling the exhaust gas temperature or the corresponding exhaust gas temperature value at the exhaust system point, for example, by means of the engine control unit. Alternatively or additionally, the exhaust gas temperature can be determined by measuring the exhaust gas temperature directly at the corresponding exhaust system point, for example, by means of a temperature sensor.This applies analogously to the other values ​​determined for the method or an embodiment thereof. Measuring and modeling the same value to be determined is possible, for example for reasons of redundancy or operational safety, for plausibility checks, etc. In particular, two or more of the aforementioned first sub-criteria must be met in order for the first operating criterion to be considered fulfilled and for the internal combustion engine to be operated in the first operating mode. According to another possible embodiment, the first operating criterion is fulfilled if – as a further first sub-criterion – the current crankshaft speed has a value that falls within a first predefined speed range, encompassing values ​​from zero, in particular an idle speed, up to and including a first predefined limit speed. In other words, the system determines the current speed of the internal combustion engine's crankshaft. If the corresponding speed value lies within the first predefined speed range, the internal combustion engine continues to operate in the first operating mode, as the first sub-criterion relating to the crankshaft speed is fulfilled. If, or as long as, a second operating criterion is met, the internal combustion engine switches from the first to the second operating mode, in which the intake valve is fully closed at the second crankshaft angle (KW2). The second operating criterion can be met, for example, if the charge air has a charge air pressure whose value falls within a second predefined charge air pressure range. This range includes values ​​from the first predefined limit charge air pressure up to and including a second predefined limit charge air pressure. The current charge air pressure is determined, and if its value lies within the second predefined charge air pressure range and consequently outside the first predefined charge air pressure range, the internal combustion engine—meaning the second sub-criterion concerning charge air pressure is met—switches to the second operating mode. Furthermore, the second operating criterion can be met if the current crankshaft speed of the internal combustion engine has a value that falls within a second predefined speed range. This second range includes values ​​from the first predefined limit speed up to and including a second predefined limit speed. In other words, the system determines the current rotational speed of the internal combustion engine's crankshaft. If this speed value lies within the second predefined speed range and consequently outside the first predefined speed range, the internal combustion engine is switched to the second operating mode, as the second sub-criterion concerning the crankshaft speed is then fulfilled. The second operating criterion can also be met if the current load of the internal combustion engine has a value that falls within a second predefined load range, encompassing values ​​from the first predefined limit load value up to and including a second predefined limit load value. The internal combustion engine is therefore switched to the second operating mode when the second load-related sub-criterion is met. For this purpose, the current load is determined. If the corresponding load value lies within the second predefined load range and thus outside the first predefined load range, the second load-related sub-criterion is met. Furthermore, the second operating criterion can be met if the current gear ratio of the transmission has a value that falls within a second predefined range of gear ratio values. This second range includes values ​​from the first predefined limit value up to and including a second predefined limit value. In other words, the currently engaged and / or activated gear ratio is determined, and if the corresponding gear ratio value lies within the second predefined range and therefore outside the first predefined range, the second sub-criterion relating to the gear ratio is met, and the internal combustion engine is switched to the second operating mode. Furthermore, it is conceivable that the second operating criterion is met if the current speed of the vehicle falls within a second predefined speed range, encompassing values ​​from the first predefined speed limit up to and including a second predefined speed limit. In other words, the vehicle's current speed is determined. If the corresponding speed value lies within the second predefined speed range—and consequently outside the first—the internal combustion engine is switched to the second operating mode, as the second sub-criterion concerning the vehicle speed is fulfilled. Furthermore, the second operating criterion can be met if the current operating time, during which the internal combustion engine was last operated continuously in the first operating mode, has a value that falls within a second predefined time value range. This range includes values ​​from the first predefined limit operating time value up to and including a second predefined limit operating time value. In other words, the system determines how long the internal combustion engine was last operated continuously in the first operating mode. If this time lies within the second predefined time value range, i.e., outside the first predefined time value range, the second sub-criterion concerning operating time is met, and the internal combustion engine is switched to the second operating mode. Furthermore, the second operating criterion can be met if an exhaust gas temperature is measured at an exhaust gas tract point of the internal combustion engine, the value of which comes from a second predefined exhaust gas temperature range. This range includes values ​​from the first predefined limit exhaust gas temperature value up to and including a second predefined limit exhaust gas temperature value. The internal combustion engine is therefore switched to the second operating mode when the second sub-criterion concerning the exhaust gas temperature is met. For this purpose, the current exhaust gas temperature at the corresponding exhaust gas tract point is determined. If the corresponding exhaust gas temperature value lies within the second predefined exhaust gas temperature range and therefore outside the first predefined exhaust gas temperature range, the second sub-criterion concerning the exhaust gas temperature is met. In particular, two or more of the aforementioned second sub-criteria must be met in order for the second operating criterion to be considered fulfilled and for the internal combustion engine to be switched to the second operating mode or operated in the second operating mode. The process is specifically designed to switch the internal combustion engine to the second operating mode as early as possible, where it operates according to a Miller cycle of first Miller intensity. This advantageously reduces the exhaust gas temperature particularly early. The Miller combustion process lowers the effective compression ratio by causing a portion of the intake air in the combustion chamber to expand and then compress again due to the premature closing of the intake valve. This reduced effective compression ratio results in a lower tendency to knock. Consequently, earlier ignition timing can be set. The earlier the fuel-air mixture is ignited in the combustion chamber, the earlier combustion begins and the more advanced it is at the time the exhaust valve opens. This results in a lower exhaust gas temperature.This ensures that components interacting with the exhaust gas – for example, an exhaust-driven turbine in the charge air compressor, an exhaust aftertreatment system, etc. – come into contact with particularly cool exhaust gas, effectively preventing undesirably high temperatures, especially reaching the specified temperature limits. Furthermore, the switch from the first to the second operating mode is torque-neutral. This means that the intake valve timing and boost pressure are adjusted while maintaining the current torque. Therefore, vehicle occupants do not notice the change in operating mode. Only when a third operating criterion is met, which is specified in particular for component protection of the internal combustion engine components or their peripheral components and / or assemblies that come into contact with the exhaust gas and / or charge air, is the internal combustion engine switched from the second to the third operating mode, in which the intake valve is fully closed at the third crankshaft angle (KW3). Specifically, the internal combustion engine will only operate in the third operating mode as long as the third operating criterion is met. The third operating criterion can be met, for example, if the charge air has a charge air pressure whose value comes from a third predefined charge air pressure range that includes only values ​​from the second predefined limit charge air pressure and higher charge air pressure values.The current charge air pressure is determined, and if its value is within the third specified charge air pressure range and consequently neither in the first nor in the second specified charge air pressure range, the internal combustion engine - since the third sub-criterion relating to charge air pressure is fulfilled - is switched to the third operating mode. Furthermore, the third operating criterion can be met if the current crankshaft speed of the internal combustion engine has a value that falls within a third predefined speed range, which includes only values ​​from the second predefined limit speed and higher speeds. In other words, the system determines the current speed of the internal combustion engine's crankshaft. If the corresponding speed value lies within the third predefined speed range and consequently neither within the first nor the second predefined speed range, the internal combustion engine is switched to the third operating mode, as the third sub-criterion relating to the crankshaft speed is fulfilled. The third operating criterion can also be met if the current load of the internal combustion engine has a value that falls within a third predefined load value range, which includes only values ​​below the first and second predefined limit load values ​​and higher load values. The internal combustion engine is therefore switched to the third operating mode when the third load-related sub-criterion is met. For this purpose, the current load is determined. If the corresponding load value lies within the third predefined load value range, i.e., neither within the first nor the second predefined load value range, the third load-related sub-criterion is met. Furthermore, the third operating criterion can be met if the current gear ratio of the transmission has a value that falls within a third predefined range of gear ratio values, which includes only values ​​from the second predefined range and higher gear ratio values. Thus, the currently engaged and / or activated gear ratio is determined, and if the corresponding gear ratio value lies within the third predefined range—outside the first and second predefined ranges—the third sub-criterion relating to the gear ratio is met, and the internal combustion engine is switched to the third operating mode. Furthermore, it is conceivable that the third operating criterion is met if the current speed of the vehicle falls within a third predefined speed range, which includes only values ​​from the second predefined limit speed and higher speeds. In other words, the vehicle's current speed is determined. If the corresponding speed value lies within the third predefined speed range—and thus neither within the first nor the second predefined speed range—the internal combustion engine is switched to the third operating mode, as the third sub-criterion relating to the vehicle speed is fulfilled. The third operating criterion can also be met if a current continuous operating time, during which the internal combustion engine was last operated continuously in the second operating mode, has a value that falls within a third predefined time value range. This range includes only values ​​from the second predefined limit operating time value and higher operating time values. In other words, the system determines how long the internal combustion engine was last operated continuously in the second operating mode. If this time lies within the third predefined time value range, i.e., outside the first predefined time value range, the second sub-criterion concerning operating time is met, and the internal combustion engine is switched to the second operating mode. Furthermore, the third operating criterion can be met if an exhaust gas temperature is measured at an exhaust gas tract point of the internal combustion engine, the value of which comes from a third predefined exhaust gas temperature range that includes only values ​​from a second predefined limit exhaust gas temperature value and higher exhaust gas temperature values. The internal combustion engine is therefore switched to the third operating mode when the third sub-criterion relating to exhaust gas temperature is met. For this purpose, the current exhaust gas temperature at the corresponding exhaust gas tract point is determined. If the corresponding exhaust gas temperature value lies within the third predefined exhaust gas temperature range and therefore outside the first and second predefined exhaust gas temperature ranges, the third sub-criterion relating to exhaust gas temperature is met. In particular, two or more of the aforementioned third sub-criteria must be met for the third operating criterion to be considered fulfilled and for the internal combustion engine to be switched to or operated in the third operating mode. It may also be stipulated that the internal combustion engine will continue to operate in the second operating mode as long as the third operating criterion is met. In particular, it is stipulated that the values ​​of the second specified charge air pressure range are all greater than the largest value of the first specified charge air pressure range, the values ​​of the second specified speed range are greater than the largest value of the first specified speed range, the values ​​of the second specified load range are all greater than the largest value of the first specified load range, the values ​​of the second specified gear ratio range are all greater than the largest value of the first specified gear ratio range, and the values ​​of the second specified speed range are all greater than the largest value of the first specified speed range.the values ​​of the second specified time value range are all greater than the largest value of the first specified time value range and / or the values ​​of the second specified exhaust gas temperature value range are all greater than the largest value of the first specified exhaust gas temperature value range. In the third operating mode, the internal combustion engine operates according to a Miller cycle of second Miller intensity, where the first Miller intensity of the second operating mode is lower than the second Miller intensity of the third. Compared to the second operating mode, the charge air compressor must provide a higher charge air pressure in the third operating mode, thus placing a greater load on the compressor. This is accepted, however, in order to sufficiently reduce the exhaust gas temperature in the third operating mode to maintain or not exceed a maximum permissible exhaust gas temperature at which the intended function of the corresponding component is still guaranteed. This means that the maximum permissible exhaust gas temperature must be strictly adhered to during the operation of the internal combustion engine for component protection reasons, to prevent damage to the corresponding component. In particular, the sub-criteria are mutually exclusive. In other words, either the first sub-criterion, the second sub-criterion, or the third sub-criterion is met, as the specified value ranges do not overlap. The procedure is specifically designed so that the operating modes do not overlap. In other words, the first operating mode is active when neither the second nor the third operating mode is active. The second operating mode is active when neither the first nor the third operating mode is active. The third operating mode is active when neither the first nor the second operating mode is active. Furthermore, the procedure is specifically designed so that when the third operating mode is active, the system switches from the third to the second operating mode as soon as possible. In other words, the third operating mode is used only to reduce the exhaust gas temperature until it falls below the limit temperature. In other words, the system switches from the third to the second operating mode when the exhaust gas temperature falls below the limit temperature.In particular, a switch-back limit temperature is specified for switching from the third to the second operating mode, which is lower than the limit exhaust gas temperature and which comes into play instead of the limit exhaust gas temperature when switching from the third to the second operating mode. This prevents switching back and forth between the second and third operating modes. Only if the conditions for operating the internal combustion engine in the second operating mode are not yet or no longer met, is the internal combustion engine switched to the first operating mode according to the procedure, for example, when the charge air pressure falls below the limit charge air pressure and / or a crankshaft speed and / or a load on the internal combustion engine prevent the use of the Miller cycle. In particular, at least one intermediate operating mode for the internal combustion engine is conceivable. For example, in a first intermediate operating mode, the intake valve may close later than in the second, but earlier than in the first. Furthermore, a second intermediate operating mode is conceivable in which the intake valve closes later than in the third, but earlier than in the second. Between the first and second operating modes and / or between the second and third operating modes, two or more different first and second intermediate operating modes (each with a different Miller cycle intensity) may be provided. This allows for particularly fine adjustment of the Miller cycle intensity. The method is transferable to the intermediate operating mode(s).If the first operating criterion (or another / additional first operating criterion, possibly with further and / or different first sub-criteria) is met, the system can switch from the first operating mode to one of the first intermediate operating modes. If the second operating criterion (or another / additional second operating criterion, possibly with further and / or different second sub-criteria) is met, the system can switch from this intermediate mode to another of the (first or second) intermediate operating stages or to the third operating mode. This process enables particularly efficient and low-emission operation of the internal combustion engine, keeping the exhaust gas temperature below the limit temperature while maintaining a consistently stoichiometric fuel-air ratio (λ = 1). Specifically, it avoids enriching the fuel-air mixture (λ < 1) to cool the exhaust gas, as this leads to increased emissions from the engine and a low conversion rate of any catalytic converter connected to the exhaust side of the engine. Furthermore, it ensures that the thermal stress on components interacting with the exhaust gas does not exceed permissible limits due to the third operating condition. Current legal requirements, which stipulate low emission limits across the entire operating range of the internal combustion engine, are met.Furthermore, higher driving performance is possible with the vehicle, which uses an internal combustion engine as its drive system. Thanks to the variably controllable intake spread, higher performance can be achieved in the first and second operating modes than in the third operating mode. According to another possible embodiment, the first crankshaft angle KW1 or the first crankshaft angle range [KW1] and the second crankshaft angle KW2 or the second crankshaft angle range [KW2] are spaced apart from each other by a first angular distance, which is in particular more than 10° or more than 30°. Alternatively or additionally, the second crankshaft angle KW2 and the third crankshaft angle KW3 or the second crankshaft angle range [KW2] and the third crankshaft angle range [KW3] are spaced apart from each other by a second angular distance, which is in particular more than 5°. In particular, the first angular distance by which the crankshaft angles KW1, KW2 or the crankshaft angle ranges [KW1], [KW2] are spaced apart from each other is greater than the second angular distance by which the crankshaft angles KW2, KW3 or the crankshaft angle ranges [KW2], [KW3] are spaced apart from each other. A possible further development aims to ensure that switching between the first and second operating modes and / or between the second and third operating modes is stepless. This guarantees particularly gentle switching between the operating modes of the internal combustion engine. Alternatively or additionally, switching between the first and second operating modes and / or between the second and third operating modes can be performed in discrete steps. In another possible embodiment of the method, determining the exhaust gas temperature includes determining a first exhaust gas temperature at a first exhaust gas tract point. This first exhaust gas tract point is associated with a turbine of an exhaust gas turbocharger of the internal combustion engine, specifically located in / on an inlet section of the turbine through which the exhaust gas flows during operation of the internal combustion engine to drive the turbine impeller. Alternatively or additionally, determining the exhaust gas temperature includes determining a second exhaust gas temperature at a second exhaust gas tract point, which is associated with an inlet side of an exhaust aftertreatment device, such as a catalytic converter, of the internal combustion engine. This second exhaust gas tract point is specifically located in / on an inlet channel section of the exhaust aftertreatment device through which the exhaust gas flows during operation of the internal combustion engine.Alternatively or additionally to determining the first and / or second exhaust gas temperature at the first or second exhaust gas tract point, it is further provided that determining the exhaust gas temperature includes determining a third exhaust gas temperature at a third exhaust gas tract point. The third exhaust gas tract point is assigned to an aftertreatment chamber of the exhaust aftertreatment system, for example, a conversion chamber of the catalyst, through which the exhaust gas flows, and is located, for example, within the aftertreatment chamber. The respective exhaust gas temperature can be measured, for example, using appropriately configured temperature sensors. Alternatively or additionally, one or more of the exhaust gas temperatures can be modeled, for example, using the control unit. The first sub-criterion concerning exhaust gas temperature is considered fulfilled if the value of the first exhaust gas temperature is from the first exhaust gas temperature range, and / or if the value of the second exhaust gas temperature is from the first exhaust gas temperature range, and / or if the value of the third exhaust gas temperature is from the first exhaust gas temperature range. An individual first exhaust gas temperature range is provided for each exhaust system section. This means, for example, that a first exhaust gas temperature range assigned to the first exhaust system section may contain different exhaust gas temperature values ​​than a first exhaust gas temperature range assigned to the second exhaust system section.The second sub-criterion concerning exhaust gas temperature is considered fulfilled if the value of the first exhaust gas temperature is from the second exhaust gas temperature range, and / or if the value of the second exhaust gas temperature is from the second exhaust gas temperature range, and / or if the value of the third exhaust gas temperature is from the second exhaust gas temperature range. For each exhaust system section, an individual first and / or an individual second exhaust gas temperature range is provided. This means that, for example, a first / second exhaust gas temperature range assigned to the first exhaust system section may contain different exhaust gas temperature values ​​than a first / second exhaust gas temperature range assigned to the second exhaust system section. This applies analogously to the other exhaust system sections.The third sub-criterion concerning exhaust gas temperature is considered fulfilled if the value of the first exhaust gas temperature is from the third exhaust gas temperature range and / or if the value of the second exhaust gas temperature is from the third exhaust gas temperature range and / or if the value of the third exhaust gas temperature is from the third exhaust gas temperature range. An individual third exhaust gas temperature range is provided for each exhaust system section. This means, for example, that a third exhaust gas temperature range assigned to the first exhaust system section may contain different exhaust gas temperature values ​​than a third exhaust gas temperature range assigned to the second exhaust system section. This applies analogously to the other exhaust system sections. This ensures that the exhaust gas temperatures at various points in the internal combustion engine are taken into account with particular precision. Furthermore, a plausibility check can be implemented. For example, if an implausibly high exhaust gas temperature is measured at the first exhaust gas tract point, exceeding the first limit exhaust gas temperature, switching from the second to the third operating mode can be avoided if a plausible exhaust gas temperature is measured at the second exhaust gas tract point, which is below the second limit exhaust gas temperature. Further features of the invention may become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures themselves, can be used not only in the combinations specified, but also in other combinations or on their own, without departing from the scope of the invention. The drawing shows in Fig. 1, for an approximately 20-second powered acceleration of an internal combustion engine having a crankshaft, which is controlled by means of a method for controlling an internal combustion engine, over a common time axis: a) a crankshaft speed curve of the internal combustion engine and a gear ratio curve of a gear transmission coupled to the crankshaft, b) an active state curve of three operating modes of the internal combustion engine, c) a curve of an intake valve spread angle, which indicates at which angular position of the crankshaft relative to its top dead center position the intake valve is open with a maximum lift, d) a charge air pressure curve and e) a charge air temperature curve, Fig.2. To illustrate the operating modes and the associated intake valve spread angles, the schematically depicted crankshaft is shown a) in a top dead center position, b) in a first angular position moved from the first dead center position by a first crankshaft angle, c) in a second angular position moved from the first dead center position by a second crankshaft angle, d) in a third angular position moved from the first dead center position by a third crankshaft angle. The following is a joint description of a method for controlling an internal combustion engine, a control device configured to execute the method, an internal combustion engine unit comprising the internal combustion engine and the control device, and a motor vehicle comprising the internal combustion engine unit. In the figures, identical and functionally equivalent elements are designated with the same reference numeral. The motor vehicle comprises an internal combustion engine unit, such that the internal combustion engine of the unit forms a propulsion machine for the motor vehicle. In addition to the internal combustion engine, the unit includes a control device with means for carrying out the method of controlling the internal combustion engine. The control device provides control signals for the internal combustion engine, in particular for an intake valve train of the engine, and the engine is configured to accept the control signals provided by the control device as input control signals. Accordingly, the internal combustion engine and the control device are coupled or can be coupled to each other for the transmission of control signals. The internal combustion engine is designed as a four-stroke reciprocating engine and, in addition to the intake valve train, has a crankshaft 1, a combustion chamber, and an intake valve associated with the combustion chamber. Furthermore, the internal combustion engine has a charge air compressor, for example, an exhaust gas turbocharger, for pre-compressing charge air supplied to the combustion chamber. During firing operation of the internal combustion engine, one exhaust side of the combustion chamber is tightly closed by means of an exhaust valve to allow charge air or a fuel-air mixture to enter the combustion chamber during a charging stroke, while one intake side of the combustion chamber is opened by means of an intake valve that is at least partially open, allowing fluid to flow into the combustion chamber.To move a piston mounted for translational movement within the combustion chamber, the crankshaft 1 is rotated from its top dead center (TDC) position – shown at 0° in Fig. 2 – and in its intended operating direction 2 (see Fig. 2a) towards its bottom dead center (BDC) position – shown at 180° in Fig. 2. The charging stroke is followed by a compression stroke, during which the crankshaft 1 rotates in its operating direction from BDC (180°) towards TDC (360°). In the subsequent full revolution of the crankshaft 1, an expansion stroke (from 360° to 540°) and an exhaust stroke (from 540° to 720° = 0°) follow, and the four-stroke cycle begins again. Fig. 1 a) shows the crankshaft speed n over time t, as well as the number of gear ratios N of a transmission coupled to the internal combustion engine, during which the engine is accelerated. The internal combustion engine is controlled according to the method. Figure 1b) shows the time intervals during the acceleration process in which the internal combustion engine operates in a first operating mode B1, a second operating mode B2, and a third operating mode B3. It can be seen that the operating modes B1, B2, and B3 do not overlap. That is, the first operating mode B1 is only active when neither the second operating mode B2 nor the third operating mode B3 is active. The second operating mode B2 is active when neither the first operating mode B1 nor the third operating mode B3 is active. Consequently, the third operating mode B3 is only active when neither the first operating mode B1 nor the second operating mode B2 is active. Operating modes B1, B2, and B3 differ primarily in their respective intake valve spread angle ES, the course of which over time t is shown in Fig. 1c). Depending on the operating mode (B1, B2, or B3), the intake valve is maximally open, i.e., fully open, at a different intake valve spread angle ES1, ES2, or ES3. The intake valve spread angle ES is a crankshaft angle measured in the direction of rotation 2 of the crankshaft 1 and starting from the top dead center (TDC) position of the crankshaft 1. It follows that, depending on the operating mode (B1, B2, or B3), the intake valve is fully closed at different crankshaft angles KW1, KW2, or KW3 with respect to the respective charging cycle. Figures 2 b), c), and d) illustrate the intake valve spread angles ES1, ES2, and ES3 at which the intake valve is open with maximum lift. It can be seen that in the first operating mode B1, the intake valve is maximally open at a first intake valve spread angle ES1. This means that at a first crankshaft angle KW1 of approximately 180°, i.e., at about bottom dead center (BDC), the intake valve is completely closed. In other words, in the first operating mode B1, the closing movement of the intake valve is completely finished at bottom dead center (BDC), or when the crankshaft has reached the first crankshaft angle KW1. The flow of charge air into the combustion chamber is completely blocked at the first crankshaft angle KW1. It is known that (for tolerance reasons, such as valve clearance, and / or to utilize advantageous thermo- or...(fluid dynamic effects) the closing of the intake valve may be completely completed shortly before or shortly after bottom dead center, but in any case in a close range around bottom dead center (BDC), for example in a range of ± 10° around BDC. Therefore, the first intake valve spread angle ES1 is derived in particular from a first intake valve spread angle range [ES1], and consequently, the first crankshaft angle KW1 is derived in particular from a first crankshaft angle range [KW1]. In the second operating mode B2, the intake valve is fully open at a second intake valve spread angle ES2. This means that the intake valve closes earlier compared to the first operating mode B1, i.e., at a second crankshaft angle KW2 and in any case before the crankshaft 1 has reached its first crankshaft angle KW1. As a result, the flow of charge air into the combustion chamber is completely blocked even during the charging stroke. Thus, the internal combustion engine operates in a Miller cycle of first Miller intensity. The second intake valve spread angle ES2 can originate from a second intake valve spread angle range [ES2], which means that the second crankshaft angle KW2 can originate from a second crankshaft angle range [KW2]. The first crankshaft angle KW1, or its angular range [KW1], and the second crankshaft angle KW2, or its angular range [KW2], are separated from each other by a first angular interval. This means that the first intake valve spread angle ES1, or its angular range [ES1], and the second intake valve spread angle ES2, or its angular range [ES2], can be separated from each other by this first angular interval. The first angular interval is greater than 10°, and in particular greater than 30°. The intake valve closes, for example, 40° earlier in the first Miller cycle, or in the second operating mode B2, compared to the first operating mode B1. In the third operating mode B3, the intake valve is fully open at a third intake valve spread angle ES3, which means that the intake valve closes even earlier compared to the second operating mode B2, namely at a third crankshaft angle KW3. This results in the internal combustion engine operating in a Miller cycle of second Miller intensity. The third crankshaft angle KW3 can be derived from a third crankshaft angle range [KW3], and the third intake valve spread angle ES3 can be derived from a third intake valve spread angle range [ES3]. The second crankshaft angle KW2, or its angular range [KW2], and the third crankshaft angle KW3, or its angular range [KW3], are separated by a second angular distance greater than 5°. Therefore, the intake valve spread angle ranges [ES2] and [ES3] can be separated by this second angular distance.The closing of the intake valve is completed earlier in the second Miller cycle intensity (i.e., in the third operating mode B3) compared to the first operating mode B1, and even earlier compared to the second operating mode B2. Thus, the effects associated with a Miller cycle are more pronounced in the second Miller cycle intensity (i.e., in the third operating mode B3) than in the second operating mode B2; the second operating mode B2 has the first, weak Miller intensity, and the third operating mode B3 has the second, strong Miller intensity. The procedure determines the charge air pressure. The boost air pressure curve pL during the fired acceleration considered here is shown in Fig. 1 d) over time t. In particular, the crankshaft speed and load of the internal combustion engine are determined. Additionally, the current gear ratio of a transmission coupled to the internal combustion engine and the current vehicle speed are determined. Furthermore, the current operating time of the internal combustion engine and the exhaust gas temperature at an exhaust system point are determined.One, some, or all of the values ​​determined here—namely, boost pressure, crankshaft speed (RPM), load, gear ratio, vehicle speed, operating time, and exhaust gas temperature—can be modeled, for example, by the engine control unit. Alternatively or additionally, one, some, or all of these values ​​can be measured, for example, by a suitably configured and positioned sensor. In this case, for instance, the exhaust gas temperature is determined by modeling the exhaust gas temperature at the exhaust manifold point using the engine control unit. The internal combustion engine operates in the first operating mode B1 if and as long as a first operating criterion is met. In this example, the first operating criterion is considered met if one of the first sub-criteria is met, or if two or more of the first sub-criteria are met. The first sub-criteria are as follows: - The charge air currently has a charge air pressure pLauf, the value of which comes from a first predefined charge air pressure range, which includes values ​​from zero up to and including a first predefined limit charge air pressure value GpL. - The current crankshaft speed n has a value that comes from a first predefined speed range, which includes values ​​from zero, in particular from an idle speed value, up to and including a first predefined limit speed value.- The current load has a value derived from a first predefined load value range, which includes values ​​from zero up to and including a first predefined limit load value. - The current gear ratio N of the transmission has a value derived from a first predefined gear ratio value range, which includes values ​​from zero up to and including a first predefined limit gear ratio value. - The current vehicle speed has a value derived from a first predefined speed value range, which includes values ​​from zero up to and including a first predefined limit speed value. - The current operating time, during which the internal combustion engine was last operated continuously in the first operating mode, has a value derived from a first predefined time value range, which includes values ​​from zero up to and including a first predefined limit operating time value.- The exhaust gas temperature is determined at the exhaust tract point of the internal combustion engine, the value of which comes from a first predetermined exhaust gas temperature value range, which includes values ​​from zero up to and including a first predetermined limit exhaust gas temperature value. In this process, the internal combustion engine switches from the first operating mode B1 to the second operating mode B2 when a second operating criterion is met. In this example, the second operating criterion is considered met if one of the second sub-criteria is met, or if two or more of the second sub-criteria are met. The second sub-criteria are as follows: - The charge air currently has a charge air pressure pLauf, the value of which is taken from a second predefined charge air pressure range, encompassing values ​​from the first predefined limit charge air pressure GLauf (exclusively) up to and including a second predefined limit charge air pressure. - The current crankshaft speed has a value taken from a second predefined speed range, encompassing values ​​from the first predefined limit speed up to and including a second predefined limit speed.- The current load has a value derived from a second predefined load value range, which includes values ​​from the first predefined limit load value up to and including a second predefined limit load value. - The current gear ratio of the transmission has a value derived from a second predefined gear ratio value range, which includes values ​​from the first predefined limit gear ratio up to and including a second predefined limit gear ratio. - The current vehicle speed has a value derived from a second predefined speed value range, which includes values ​​from the first predefined limit speed up to and including a second predefined limit speed.- The current operating time, during which the internal combustion engine was last operated continuously in the first operating mode, has a value derived from a second predefined time value range, which includes values ​​from the first predefined limit operating time value exclusively up to and including a second predefined limit operating time value. - An exhaust gas temperature is determined at the exhaust system point, the value of which is derived from a second predefined exhaust gas temperature value range, which includes values ​​from the first predefined limit exhaust gas temperature value exclusively up to and including a second predefined limit exhaust gas temperature value. The internal combustion engine is therefore operated in the first operating mode B1 as long as one or more of the second sub-criteria are not met, for example, as long as the charge air pressure pL is lower than the limit charge air pressure GpList. It is intended that the internal combustion engine is switched to the second operating mode B2 as early as possible and that it is operated in the second operating mode B2 for as long as possible. It can be seen from Fig. 1 d) that in the second operating mode B2 the charge air compressor delivers a higher charge air pressure than in the first operating mode B1. The switching from the first operating mode B1 to the second operating mode B2, and vice versa, is currently stepless. Alternatively, it is conceivable that the switching from the first operating mode B1 to the second operating mode B2, and vice versa, could be performed via discrete steps. According to the procedure, the internal combustion engine is switched from the second operating mode B2 to the third operating mode B3 only if this is necessary for component protection. A third operating criterion is provided for this purpose, whereby the internal combustion engine is switched from the second operating mode B2 to the third operating mode B3, or operates in the third operating mode B3, if the third operating criterion is met. In this example, the third operating criterion is considered met if one of the third sub-criteria is met, or if two or more of the third sub-criteria are met. The third sub-criteria are as follows: - The charge air has a current charge air pressure prun, the value of which comes from a third predefined charge air pressure range that includes values ​​from the second predefined limit charge air pressure Grun and higher.- The current crankshaft speed has a value derived from a third predefined speed range, which includes only values ​​from and above the second predefined limit speed value. - The current load has a value derived from a third predefined load range, which includes only values ​​from and above the second predefined limit load value. - The current gear ratio of the transmission has a value derived from a third predefined gear ratio range, which includes only values ​​from and above the second predefined limit gear ratio. - The current vehicle speed has a value derived from a third predefined speed range, which includes only values ​​from and above the second predefined limit speed value.- The current operating time, during which the internal combustion engine was last operated continuously in the second operating mode, has a value derived from a third predefined time value range, which includes only values ​​from and above the second predefined limit operating time value. - An exhaust gas temperature is determined at the exhaust system point, the value of which is derived from a third predefined exhaust gas temperature value range, which includes only values ​​from and above the second predefined limit exhaust gas temperature value. For example, if the measured exhaust gas temperature is higher than a predefined limit, the internal combustion engine switches to the third operating mode, B3. Specifically, as soon as the exhaust gas temperature allows it again—that is, as soon as the measured exhaust gas temperature at the corresponding exhaust system point falls below a predefined limit—the internal combustion engine switches back to the second operating mode, B2. In this case, a switchback limit temperature is specified for switching from the third operating mode, B3, to the second operating mode, B2. This limit temperature is lower than the limit and is applied instead of the limit when switching from the third operating mode, B2, to the second operating mode, B3. The switching between the second operating mode, B2, and the third operating mode, B3, is stepless.Alternatively, it is conceivable that switching from the second operating mode B2 to the third operating mode B3 or vice versa is done via discrete stages. The internal combustion engine can furthermore be operated in a first intermediate operating mode, characterized by an intake valve spread angle ES that is smaller than the first intake valve spread angle ES1 but larger than the second intake valve spread angle ES2. This means that in the first intermediate operating mode, the intake valve closes at a crankshaft angle that is smaller than the first crankshaft angle KW1 and larger than the second crankshaft angle KW2. The internal combustion engine can also be operated in a second intermediate operating mode, characterized in particular by an intake valve spread angle ES that is smaller than the second intake valve spread angle ES2 and larger than the third intake valve spread angle ES3.In each second intermediate operating mode, the intake valve closes at a crankshaft angle that is smaller than the second crankshaft angle (KW2) but larger than the third crankshaft angle (KW3). Two or more first or two or more second intermediate operating modes are possible. By switching between one or more of the intermediate operating modes (for example, first operating mode B1 - first intermediate operating mode - further first intermediate operating mode(s) - second operating mode B2 - second intermediate operating mode - further second intermediate operating mode(s) - third operating mode B3), the Miller cycle intensity can be adjusted very precisely to meet specific requirements. In this procedure, a first exhaust gas temperature is determined at a first exhaust gas tract point, a second exhaust gas temperature at a second exhaust gas tract point, and a third exhaust gas temperature at a third exhaust gas tract point. The first exhaust gas tract point is assigned to a turbine of the exhaust gas turbocharger, for example, located in / on an inlet section of the turbine, and is defined for component protection of the turbine. The second exhaust gas tract point is assigned to an inlet side of an exhaust aftertreatment system, for example, a catalytic converter, of the internal combustion engine and is specifically located in / on an inlet channel section of the exhaust aftertreatment system. A second limit exhaust gas temperature is defined for component protection of the exhaust aftertreatment system.The third exhaust tract point is assigned to an aftertreatment chamber of the exhaust aftertreatment system, for example, a conversion chamber of the catalyst, through which the exhaust gas flows, and is located, for example, within the aftertreatment chamber. A third exhaust gas temperature limit is specified here to protect the aftertreatment chamber. Each exhaust system section is assigned an individual first, second, and third exhaust gas temperature range. The first sub-criterion concerning exhaust gas temperature is considered fulfilled if the value of the first exhaust gas temperature, the second exhaust gas temperature, and / or the third exhaust gas temperature is taken from the corresponding assigned individual first exhaust gas temperature range. The second sub-criterion concerning exhaust gas temperature is considered fulfilled if the value of the first exhaust gas temperature, the second exhaust gas temperature, and / or the third exhaust gas temperature is taken from the corresponding assigned second exhaust gas temperature range.The third sub-criterion relating to the exhaust gas temperature is deemed to be fulfilled in this case if the value of the first exhaust gas temperature and / or the value of the second exhaust gas temperature and / or the value of the third exhaust gas temperature originates from the correspondingly assigned individual third exhaust gas temperature value ranges. Figure 1e) shows the temperature profile of the charge air TL over time t. It can be seen that in the second operating mode B2, the charge air temperature TL is higher than in the first operating mode B1. Measures may need to be taken to cool the charge air, for example, a particularly efficient charge air cooler, etc. A comparison of Figures 1 d) and e) shows that components and peripheral components of the internal combustion engine that come into contact with or interact with the charge air and / or exhaust gas are subjected to a higher load in the second operating mode B2 than in the first operating mode B1. This is accepted, however, in order to switch to the second operating mode as early as possible during combustion and to operate the internal combustion engine in the second operating mode as often and for as long as possible. This is because the second operating mode—that is, the Miller cycle of first or low Miller intensity—offers advantages with regard to exhaust gas temperature compared to the first operating mode B1. Thus, the components / peripheral components that interact with the exhaust gas—for example, the turbine of the charge air compressor, the exhaust aftertreatment system, especially its aftertreatment chamber, etc.—are subjected to lower temperatures.- with advantageously cool exhaust gas. Undesirably high temperatures, in particular reaching the specified limit temperature(s), are therefore effectively avoided. Using this method, the internal combustion engine is operated with a stoichiometric fuel-air ratio λ = 1, deliberately omitting enrichment of the fuel-air mixture (λ < 1) to cool the exhaust gas. If, during operation of the internal combustion engine, the exhaust gas temperature(s) exceeds the limit exhaust gas temperature(s), enrichment of the fuel-air mixture (λ < 1) to cool the exhaust gas is nevertheless omitted, and instead, the system switches to the third operating mode – i.e., the Miller cycle of second or strong Miller intensity.Thus, the internal combustion engine operates with a fuel-air ratio λ = 1, even under high loads, especially at a steady full load, with the exhaust gas temperature(s) not exceeding the specified limit(s). Current legal requirements, which prescribe particularly low emission limits across the entire operating range of the internal combustion engine, are met. The method for controlling the internal combustion engine, the control device designed to carry out the method, the internal combustion engine and the motor vehicle containing the internal combustion engine demonstrates a particular possibility of operating an internal combustion engine in a particularly efficient and low-emission manner. Reference symbol list 1 Crankshaft 2 Working direction CW1 first crankshaft angle [CW1] first crankshaft angle range CW2 second crankshaft angle [CW2] second crankshaft angle range CW3 third crankshaft angle [CW3] third crankshaft angle range TDC top dead center position of the crankshaft BDC bottom dead center position of the crankshaft B1 first operating mode B2 second operating mode or first Miller cycle B3 third operating mode or second Miller cycle ES1 first intake valve spread angle ES2 second intake valve spread angle ES3 third intake valve spread angle pL charge air pressure GpL limit charge air pressure TL charge air temperature

Claims

Method for controlling an internal combustion engine comprising a crankshaft (1), an intake valve, and a charge air compressor for pre-compressing charge air, wherein, during a charging stroke, the intake valve closes from a top dead center position (TDC, 0°) of the crankshaft (1) and in the direction of rotation (2) of the crankshaft (1), measured: - in a first operating mode (B1) at a first crankshaft angle (CW1) at a bottom dead center position (BDC, 180°) of the crankshaft (1); or - in a second operating mode (B2) at a second crankshaft angle (CW2) that is smaller than the first crankshaft angle (CW1) before the bottom dead center position (BDC, 180°); or - in a third operating mode (B3) at a third crankshaft angle (CW3) that is smaller than the second crankshaft angle (CW2) before the bottom dead center position (BDC, 180°), wherein the internal combustion engine - in the first operating mode (B1) is operatedif a first operating criterion is met, which is deemed to be met if one or more of the following first sub-criteria are met, namely if: - a current charge air pressure (pL) has a value that is derived from a first predetermined charge air pressure value range, which includes values ​​from zero up to and including a first predetermined limit charge air pressure (GpL), and / or - a current load of the internal combustion engine has a value that is derived from a first predetermined load value range, which includes values ​​from zero up to and including a first predetermined limit load value, and / or - a current gear ratio of a transmission coupled to the internal combustion engine has a value that is derived from a first predetermined gear ratio value range, which includes values ​​from zero up to and including a first predetermined limit gear ratio value.and / or - a current driving speed of a motor vehicle that has an internal combustion engine as its drive motor, has a value derived from a first predetermined speed value range, which includes values ​​from zero up to and including a first predetermined limit speed value, and / or - a current operating duration during which the internal combustion engine was last operated continuously in the first operating mode, has a value derived from a first predetermined time value range, which includes values ​​from zero up to and including a first predetermined limit operating duration value, and / or - an exhaust gas temperature is determined at an exhaust gas tract point of the internal combustion engine, the value of which is derived from a first predetermined exhaust gas temperature value range, which includes values ​​from zero up to and including a first predetermined limit exhaust gas temperature value,- is switched from the first operating mode (B1) to the second operating mode (B2) when a second operating criterion is met, - is switched from the second operating mode (B2) to the third operating mode (B3) when a third operating criterion is met. Method according to claim 1, characterized in that the first operating criterion is met when a further first sub-criterion is met, namely when a current crankshaft speed has a value that originates from a first predetermined speed value range, which includes values ​​from zero, in particular from an idle speed value, up to and including a first predetermined limit speed value. A method according to claim 1 or 2, characterized in that the second operating criterion is met if one or more of the following second sub-criteria are met, namely if: - the current charge air pressure (pL) has a value derived from a second predetermined charge air pressure value range, which includes values ​​from the first predetermined limit charge air pressure (GpL) exclusively up to and including a second predetermined limit charge air pressure value, and / or - the current crankshaft speed has a value derived from a second predetermined speed value range, which includes values ​​from the first predetermined limit speed value exclusively up to and including a second predetermined limit speed value, and / or - the current load of the internal combustion engine has a value derived from a second predetermined load value range.the values ​​from the first specified limit load value exclusively up to and including a second specified limit load value, and / or- the current gear ratio of the transmission coupled to the internal combustion engine has a value that comes from a second specified gear ratio range, which includes values ​​from the first specified limit gear ratio exclusively up to and including a second specified limit gear ratio, and / or- the current vehicle speed has a value that comes from a second specified speed range, which includes values ​​from the first specified limit speed value exclusively up to and including a second specified limit speed value;- the current operating time during which the internal combustion engine was last operated continuously in the first operating mode has a value,which originates from a second predetermined time value range, which includes values ​​from the first predetermined limit operating time value exclusively up to and including a second predetermined limit operating time value; - an exhaust gas temperature is determined at the exhaust gas tract point of the internal combustion engine, the value of which originates from a second predetermined exhaust gas temperature value range, which includes values ​​from the first predetermined limit exhaust gas temperature value exclusively up to and including a second predetermined limit exhaust gas temperature value. The method according to claim 3, characterized in that the third operating criterion is met if one or more of the following third sub-criteria are met, namely if: - the current charge air pressure (pL) has a value derived from a third predetermined charge air pressure value range, which includes values ​​from the second predetermined limit charge air pressure value (GpL) exclusively and higher, and / or - the current crankshaft speed has a value derived from a third predetermined speed value range, which includes values ​​from the second predetermined limit speed value exclusively and higher, and / or - the current load of the internal combustion engine has a value derived from a third predetermined load value range, which includes values ​​from the second predetermined limit load value exclusively and higher, and / or - the current gear ratio of the transmission coupled to the internal combustion engine has a valuewhich originates from a third predefined transmission stage value range, which includes only and higher values ​​from the second predefined limit transmission stage value, and / or - the current driving speed of the motor vehicle has a value that originates from a third predefined speed value range, which includes only and higher values ​​from the second predefined limit speed value, and / or - the current operating time during which the internal combustion engine was last operated continuously in the second operating mode has a value that originates from a third predefined time value range, which includes only and higher values ​​from a second predefined limit operating time value, and / or - an exhaust gas temperature is determined at the exhaust system point of the internal combustion engine, the value of which originates from a third predefined exhaust gas temperature value range.the values ​​include only those from the second specified limit exhaust gas temperature value and higher. Method according to one of the preceding claims, characterized in that - the first crankshaft angle (KW1) and the second crankshaft angle (KW2) are spaced apart from each other by a first angular distance, which is in particular more than 10° or more than 30°, and / or - the second crankshaft angle (KW2) and the third crankshaft angle (KW3) are spaced apart from each other by a second angular distance, which is in particular more than 5°. Method according to one of claims 2 to 5, characterized in that the determination of the exhaust gas temperature comprises determining a first exhaust gas temperature at a first exhaust gas tract point which is assigned to a turbine of an exhaust gas turbocharger of the internal combustion engine. Method according to one of claims 2 to 6, characterized in that the determination of the exhaust gas temperature comprises determining a second exhaust gas temperature at a second exhaust gas tract location, which is assigned to an inlet side of an exhaust gas aftertreatment device of the internal combustion engine. Method according to one of claims 2 to 7, characterized in that the measurement of the exhaust gas temperature comprises measuring a third exhaust gas temperature at a third exhaust gas tract point, which is assigned to an aftertreatment chamber of the exhaust gas aftertreatment device through which the exhaust gas flows. Control device for an internal combustion engine, wherein the control device is configured to perform the method designed according to one of the preceding claims. Internal combustion engine unit comprising an internal combustion engine and a control device designed according to claim 9, which is coupled or can be coupled to the internal combustion engine for controlling the internal combustion engine. Motor vehicle with an internal combustion engine unit designed according to claim 10.

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