EP3625446A1

EP3625446A1 - Method for operating an internal combustion engine, device, and internal combustion engine

Info

Publication number: EP3625446A1
Application number: EP18725464.4A
Authority: EP
Inventors: G nther SCHMIDT; Ralf Speetzen
Original assignee: MTU Friedrichshafen GmbH
Current assignee: Rolls Royce Solutions GmbH
Priority date: 2017-05-18
Filing date: 2018-05-15
Publication date: 2020-03-25
Also published as: US20200080471A1; DE102017110855A1; WO2018210817A1; DE102017110855B4; CN110799738A

Abstract

The invention relates to a method for operating an internal combustion engine comprising a motor which has a crankshaft, wherein a charge air flow delivered to the motor is compressed by means of a compressor via a second rotational movement, and a power turbine for producing a first rotational movement is charged with an exhaust gas flow discharged from the motor. According to the invention the following steps are provided: in a first operational mode operating the internal combustion engine in four-stroke mode, and in a second operational mode operating the internal combustion engine in two-stroke mode. Furthermore, according to the invention the crankshaft can be driven by the power turbine via the first rotational movement, and the compressor can be driven by the crankshaft via the second rotational movement, wherein the second rotational movement for the compressor can be set differently from the first rotational movement of the power turbine.

Description

Method for operating an internal combustion engine, device, internal combustion engine

The invention relates to a method for operating an internal combustion engine having an engine having a crankshaft, wherein a charge air flow supplied to the engine is compressed by means of a compressor via a second rotational movement and applied to a Nutzturbine for generating a first rotational movement with an exhaust gas stream discharged from the engine becomes. The invention also relates to an internal combustion engine which is operated in accordance with the method and to a device for operating the internal combustion engine.

Advantageous solutions for improved charging of internal combustion engines are known in the art. For example, DE 10 2010 043 027 A1 describes an internal combustion engine with a compressor that can be driven by a drive that is separate from the internal combustion engine. Further, in DE 10 2011 079 036 AI an internal combustion engine is described, comprising an internal combustion engine with an exhaust gas side and a Ladefluidseite and a charging system comprising a Abgasturbo loader for charging the internal combustion engine, with a compressor assembly on the charging fluid side and a turbine assembly on the exhaust side and a compressor, whose primary side is connected to the charging fluid side and whose secondary side is connected to the exhaust side. Here, a designed as a motor / generator electric machine is provided, which is coupled to the internal combustion engine, wherein the electric machine is driven as a generator of the internal combustion engine or can drive the engine as a motor and wherein the compressor is driven by a mechanical drive coupling directly from the electric machine.

A method for operating an internal combustion engine independently of a charge, in particular for switching an engine from four-stroke operation to two-stroke operation, are also generally known. Thus, US Pat. No. 7,421,981 describes a shift mechanism that can selectably switch between two-stroke operation and four-stroke operation of an engine, the shift mechanism being switchable between engagement with a first cam lobe for four-stroke operation and engagement with a second cam lobe for one Two-stroke operation.

This basically advantageous approach is characterized by a selective switchability between two-stroke operation and four-stroke operation depending on the boundary conditions and requirements during operation.

It is desirable to further improve a method for operating a supercharged internal combustion engine, in particular with regard to technical and economic aspects.

At this point, the invention begins, whose task is to provide a method in an improved manner, at least one of the above problems, in particular regarding a possibility of switching between two-stroke operation and four-stroke operation of a supercharged internal combustion engine, addressed.

The object, concerning the method, is solved by the invention with a method of claim 1.

The invention is based on a method for operating an internal combustion engine with an engine having a crankshaft, wherein a charge air flow supplied to the engine is compressed by means of a compressor via a second rotational movement and a power turbine for generating a first rotational movement with a discharged from the engine Exhaust gas flow is applied.

According to the invention, the method further comprises the steps of operating the internal combustion engine in four-stroke mode in a first operating mode, operating the internal combustion engine in two-stroke mode in a second operating mode.

According to the invention, it is further provided in the method that the crankshaft can be driven by the useful turbine via the first rotational movement, the compressor can be driven by the crankshaft via the second rotational movement, wherein the second rotational movement is achieved Rotational movement for the compressor can set different from the first rotary movement of the power turbine.

This means, in particular, that the utility turbine and compressor are, so to speak, "mechanically decoupled" -that is, above all, "not directly mechanically connected to one another" - are. Thus, the turbine and compressor to a crankshaft of the engine are mechanically and torque-transmitting independently coupled.

The invention is based on the consideration that a possibility of switching between two-stroke operation and four-stroke operation during operation of an internal combustion engine is associated with significant advantages. These advantages relate in particular to the greater flexibility for achieving optimum operating states of the engine, in particular with regard to consumption, performance and pollutant emissions. In a two-stroke engine, the real power with the same space and weight of the engine is up to about 70% higher than a four-stroke engine. In contrast, there are construction-related disadvantages of the two-stroke engine, in particular the higher fuel consumption and higher pollutant emissions. In particular, by a possibility of switching between two-stroke operation and four-stroke operation, the advantages of both modes can be combined. The invention has now further recognized that the use of suitable flushing in two-stroke operation, the engine of a supercharged internal combustion engine is advantageous for the implementation of both modes, namely four-stroke operation and two-stroke operation is suitable. The invention has further recognized that different flushing pressures or purge gradients are required for both operating modes, namely two-stroke and four-stroke operation. The purging gradient here denotes the pressure difference between compressed fresh or charge air after compression and the exhaust gas discharged from the engine before entering the power turbine.

In a two-stroke operation, a favorable purging gradient is usually higher, since the process of loading fresh gas into a cylinder and the process of ejecting exhaust gas from a cylinder is not - in contrast to the four-stroke operation - in separate cycles, but together during a tact. For this process, also referred to as rinsing, the incoming fresh gas into the cylinder must in particular have a sufficiently high pressure be acted upon to displace the exhaust gas located in the cylinder in an effective manner. This applies - here listed only for example - especially for a particularly advantageous head reversal flushing. In any downstream exhaust turbochargers (ATL), the exhaust back pressure is further increased and the compression of the fresh gas must be further increased to ensure effective flushing of the cylinder.

Since modern engines are usually operated with an exhaust gas turbocharger, they can, in particular due to the rigid, or mechanically-directly coupled, connection between ATL turbine and ATL compressor, in the engine map sometimes only relatively small differential pressures or scavenging of In particular realize about 0.6 bar. This value is in a non-optimal range, especially for a two-stroke operation. Therefore, the switching between two-stroke operation and four-stroke operation in a way leading to technical and economic benefits so far only limited possible. The invention has recognized from these factual relationships, above all, that a variable-performance adjustable compressor makes it possible to set a required for a particular purge gradient boost pressure in an advantageous manner, since the boost pressure can be adjusted independently of the exhaust back pressure. According to the invention, it is therefore provided that the crankshaft can be driven by the power turbine via the first rotational movement, the compressor can be driven by the crankshaft via the second rotational movement, wherein the second rotational movement for the compressor can be different from the first rotational movement of the power turbine ,

The concept of the invention leads to the solution of the problem also to a device according to claim 11 for the operation of an internal combustion engine and an internal combustion engine according to claim 12.

Accordingly, the device is provided for operating an internal combustion engine having a motor and a charger arrangement, wherein a charge air flow supplied to the engine is compressed by means of at least one compressor and at least one turbine can be acted upon by an exhaust gas flow discharged from the engine, in particular designed for carrying out a method according to the concept of the invention for operating an internal combustion engine, wherein the crankshaft of the power turbine is drivable via the first rotational movement, the compressor is driven by the crankshaft via the second rotational movement wherein the second rotational movement for the compressor is different from the can set the first rotary movement of the power turbine.

The internal combustion engine comprises a motor and a supercharger arrangement, wherein the supercharger arrangement comprises: a power turbine for converting energy of an exhaust gas stream of the engine into a rotary movement, a compressor for compressing a charge air flow for the engine, wherein the internal combustion engine is designed to carry out a method according to the concept of the invention and / or a device for operating an internal combustion engine.

Advantageous developments of the invention can be found in the dependent claims and specify in particular advantageous ways to realize the above-described concept within the scope of the problem and with regard to further advantages.

In particular, according to a concept of a development of the compressor is not directly mechanically coupled to the power turbine, but only indirectly, namely both compressor and turbine can be coupled to the crankshaft of the engine by means of a clutch assembly, is still an advantageous way of energy recovery from the exhaust stream reached.

In particular, the "indirect clutch" means that the utility turbine and compressor are coupled via the crankshaft (rather than directly and rigidly, for example via a turbocharger shaft); they are, so to speak, "mechanically decoupled" -that is, above all, "not directly mechanically interconnected" -. "Indirect" in this sense thus means that the turbine and compressor to the crankshaft of the engine are coupled mechanically and torque transmitting.

The energy recovered by the power turbine from the exhaust gas flow is thus not used directly, or not exclusively for compressing the charge air, but according to the concept of the invention, first by coupling the power turbine with the crankshaft of the engine in the form of a rotary motion and thus in the form of kinetic energy returned to the engine.

From the crankshaft, this recirculated kinetic energy, together with the kinetic energy generated by the engine and the resulting from the inertia of the moving engine components, stored kinetic energy by an opposite output torque resulting from the primary movement of the engine, such as the propulsion movement of a vehicle, and further drivingly connected aggregates results, consumed. According to the concept of the invention, such aggregates also include, in particular, the compressor, which can be connected to the crankshaft by means of a compressor clutch. In this way, the time of energy recovery by the power turbine and the time of the energy supply for the compressor can be advantageously decoupled, this in particular in contrast to a conventional exhaust gas turbocharger (ATL).

In particular, instead of a conventional, at least partial, direct use of the exhaust gas energy for the compression of charge air in a conventional mechanically-directly coupled turbine and compressor (for example via a rigid turbocharger shaft) - a use of the exhaust energy for the recovery of mechanical energy or kinetic energy Supply of the crankshaft of the engine used by a power turbine advantageous; namely from the first rotary movement of the power turbine. This first rotary movement of the power turbine can be removed according to the concept of the invention-as a result of the decoupling of power turbine and compressor-defined via the only indirect drive - be removed by the crankshaft and / or the compressor or just not; in general, therefore, the second rotary motion for the compressor may be different than the first rotary motion of the power turbine. Accordingly, then the compressor of the power turbine is indirectly driven via a second rotational movement for the compressor in the sense that the second rotational movement for the compressor can be set differently from the first rotational movement of the power turbine. In particular, the second rotational movement for the compressor can be adjusted independently of the first rotary movement of the power turbine or adjusts itself after the operation of the engine. This second rotational movement is possibly provided by the crankshaft via their coupling to the compressor and / or the power turbine available. The second rotational movement for the compressor is thus independent of the first rotary movement of the power turbine adjustable, for example, with a suitable gear ratio or free as a result of the current operation of the engine. This is particularly advantageous if a relatively high purging gradient is to be achieved for a two-stroke operation. The concept preferably provides the basis for an engine operating in an improved manner, since the switchover possibility of two-stroke operation to four-stroke operation and the charger assembly according to the invention in a synergetic way and an efficient, in particular resource-efficient, operation without significant performance losses, in a conventional turbocharger would occur.

Furthermore, it is advantageous in this approach according to the concept that the kinetic energy obtained from the power turbine does not have to be converted into another form of energy, in particular electrical energy, as is the case with existing approaches for storage and later use, but directly, ie. H. is fed in kinetic form of the crankshaft. The same applies to conversion losses in the later reconversion, in particular in electrical energy stores from electrical to kinetic energy, which do not occur in this approach according to the concept.

Thus, with a return of the kinetic energy via the power turbine into the crankshaft according to the concept of the engine relieved, which leads to an advantageous saving of fuel.

Analogously, according to the concept for the purpose of driving the compressor, the crankshaft can be coupled to the compressor, in particular in the case of a spontaneous power requirement. By the moment of inertia of the crankshaft and possibly all torque transmitting connected components of the drive train (including the inertia of the moving vehicle), the compressor can be comparatively abruptly brought to nominal speed to meet the spontaneous power requirements - especially in comparison to a conventional, only by flow with Exhaust gas to be accelerated Abgasturbo loader.

In particular, it is provided that the method further comprises the step of: switching from a four-stroke operation of the first operating mode to a two-stroke operation of the second operating mode. Specifically, this development includes in particular the switching during operation of a four-stroke operation in a two-stroke operation, in particular according to the concept of the invention in an advantageous manner to achieve a short time higher power of the engine. This is particularly advantageously possible, since despite the two-stroke operation, a sufficiently high scavenging gradient can be generated by the mechanical decoupling of power turbine and compressor according to the concept of the invention.

Within the scope of a particularly preferred development, it is provided that the method further comprises the step of switching from a two-stroke operation of the second operating mode to a four-stroke operation of the first operating mode. Specifically, this may mean that the engine of the internal combustion engine, after it has already been switched in a previous step of a four-stroke operation in a two-stroke operation, is switched back to a four-stroke operation. This is particularly advantageous if the higher power of the two-stroke operation, which is advantageously used in transient requirements such as during acceleration, is not needed in a current operating state of the engine. In such, in particular stationary operating state, the internal combustion engine can therefore be switched in accordance with the concept of the invention in favor of a lower fuel consumption and lower pollutant emissions in a four-stroke operation.

In particular, it is provided that the power turbine can be coupled via a turbine clutch to the crankshaft of the engine. Specifically, this specifically means that the drive connection between the power turbine and the crankshaft of the engine can be closed and opened. This makes it possible in an advantageous manner to produce the transmission of the rotational movement generated by the power turbine to the crankshaft of the engine as needed, interrupt, or even adjust gradually or partially. In this way For example, it can be ensured that a slower rotating, driven by the power turbine shaft is separated from the crankshaft to avoid a braking effect on the engine. Within the scope of a particularly preferred development, it is provided that the turbine coupling is designed as a hydrodynamic coupling, in particular as a filling-controlled hydrodynamic coupling. Specifically, this specifically means that a turbine output shaft of the power turbine is connected via a hydrodynamic coupling with the crankshaft of the engine, in particular also via a transmission. In particular, according to the principle of a hydrodynamic coupling, the torque is not transmitted directly but by driving a fluid surrounding both coupling partners. As a result, it is achieved in an advantageous manner that, in particular, speed jumps of a clutch partner are transferred to the other clutch partner virtually without jerks by the continuous adjustment of the flow velocity of the fluid. In general, torsional vibrations are damped by a hydrodynamic transmission, which thus contributes positively to smoothness. Furthermore, such a development includes in particular that the fluid for coupling both coupling partners in a controlled or regulated manner in the both clutch partner enclosing the clutch space of the hydrodynamic coupling can be filled or discharged from the clutch chamber. As a result, the transmission power of the hydrodynamic coupling - and in particular the transmitted speed - can be continuously adjusted during operation in an advantageous manner.

In the context of a particularly preferred development, it is provided that the compressor can be coupled to the crankshaft of the engine via a compressor clutch. Specifically, this includes in particular that the drive connection between the crankshaft of the engine and compressor can be closed and opened as needed. This makes it possible in an advantageous manner to produce the transmission of the rotational movement generated by the crankshaft of the motor to the compressor as needed, to interrupt, or even gradually or partially adjust. Thus, advantageously, the power of the compressor and thus the degree of compression of the charge air depending on momentary requirements and currently prevailing operating conditions, in particular continuously or quasi-continuously in the manner of a control loop, can be adjusted. This is particularly advantageous compared to a conventional rigid drive connection between the turbine and compressor, in which such an adjustment is not readily possible. In particular, it is provided that the compressor clutch is designed as a hydrodynamic coupling, in particular as a filling-controlled hydrodynamic coupling. Specifically, this specifically means that a drive shaft of the compressor is connected via a hydrodynamic coupling with the crankshaft of the engine. In particular, according to the principle of a hydrodynamic coupling, the torque is not transmitted directly but by driving a fluid surrounding both coupling partners. As a result, it is achieved in an advantageous manner that, in particular, speed jumps of a clutch partner are transferred to the other clutch partner virtually without jerks by the continuous adjustment of the flow velocity of the fluid. In general, torsional vibrations are damped by a hydrodynamic transmission, which thus contributes positively to smoothness. In concrete terms, this means, in particular, that the fluid for coupling both coupling partners in a controlled or regulated manner in the clutch housing enclosing the coupling space of the hydrodynamic coupling can be filled or discharged from the clutch space. In this way, the transmission power of the hydrodynamic coupling can be continuously adjusted during operation and in particular the speed of the compressor can be controlled or regulated during operation in an advantageous manner. Furthermore, such a development includes in particular that the fluid for coupling both coupling partners in a controlled or regulated manner in the both clutch partner enclosing the clutch space of the hydrodynamic coupling can be filled or discharged from the clutch chamber. In this way, the transmission power of the hydrodynamic coupling can be continuously adjusted during operation and in particular the speed of the compressor can be controlled or regulated during operation in an advantageous manner. In particular, it is provided that the power turbine continues to be arranged via a power turbine transmission between the turbine clutch and crankshaft, with the crankshaft can be coupled. Specifically, this means that the speed of the power turbine can be changed, in particular reduced, before it is fed into the engine. For this purpose, the speed of the generally higher-speed turbine can be reduced by a transmission, in particular with a transmission ratio of i = 25-30. In this way, the use of recovered exhaust gas energy in mechanical form is advantageously made possible by the direct transfer to the crankshaft of the engine. In the context of a particularly preferred embodiment, it is provided that the compressor is further arranged via a compressor transmission between compressor clutch and crankshaft, with the crankshaft can be coupled. Specifically, this includes in particular that the speed of the crankshaft of the engine by means of a compressor transmission changed, in particular increased, is to drive the compressor with an adapted, in particular for compressing the charge air sufficiently high speed. This makes it possible in an advantageous manner to use the rotational movement of the motor directly by means of a corresponding translation for the charge air compression. Within the scope of a preferred development, the invention has recognized that, in particular, a head reversal purge proves to be advantageous for use as a purge method in two-stroke operation in comparison to a two-stroke operation with a longitudinal purge; Particularly advantageous requires a head reversing flushing only minor constructive adjustments of the internal combustion engine. In particular, it is accordingly provided that when the internal combustion engine is operated in two-stroke operation, the cylinders are flushed by a head reversal flush. Specifically, this means in particular that the combustion chamber formed from cylinder and piston flushed through openings or valves, that is flooded and emptied is, which are arranged on one side of the combustion chamber, in particular on the upper inside or head side of the cylinder. Such a development leads in particular to the advantage that the structure of the engine and in particular of the individual cylinders are the same or similar to the structure of a four-stroke engine and thus requires an adaptation for enabling both operating modes only minor structural changes of the internal combustion engine. In this way it is possible, in particular, to switch between two-stroke operation and four-stroke operation, in particular by adapting the valve control, for example by means of hydraulic adjustment of the camshaft.

Furthermore, in the case of a head reversing purge, the piston, or any piston rings and / or piston seals, are not stressed mechanically by the overflow of inlet slots which are arranged to implement other rinsing methods, such as, for example, a longitudinal rinse or DC rinse, in particular in the lower cylinder region. As a result, the risk of damage or increased wear of the piston, or any piston rings and / or piston seals, advantageously reduced. The possibility of setting a higher flushing gradient, which is required in a head reversing flushing in particular compared to a longitudinal flush, is achieved by the Kuppelbarkeit of the turbine and compressor via the crankshaft of the engine according to the concept of the invention in an advantageous manner.

With regard to the internal combustion engine is provided in a development that the clutch assembly is formed electromechanically, in particular that a rotational movement in a generator current or the generator current is convertible into a rotary motion. Specifically, this includes in particular that both turbine and compressor side an arrangement consisting of generator, controller and motor allows a conversion of kinetic, in particular rotational energy into electrical energy, further a regulation and a subsequent reconversion of electrical energy into kinetic energy. By such a development can be carried out by the conversion of kinetic energy into electrical energy and vice versa particularly advantageous both turbine-side and compressor side, a speed conversion. Furthermore, it is also possible to store the kinetic energy converted into electrical energy by means of suitable energy stores, in particular rechargeable batteries, and to migrate them back into kinetic energy at a later time. In a preferred embodiment of the internal combustion engine is provided that the exhaust gas turbine drives a generator. The power generated by this generator drives an electric motor, which is mechanically connected via a suitable transmission with the crankshaft of the engine. Thus, the energy generated by the exhaust gas turbine is transmitted to the engine. By controlling the electric motor, the maximum available energy can be transmitted from the engine throughout the engine map.

In a preferred embodiment of the internal combustion engine is provided that the crankshaft of the engine mechanically drives a generator. The power generated by this generator drives an electric motor, which is mechanically connected to the compressor via a suitable gear ratio. Thus, the energy generated by the engine (regardless of the available exhaust gas enthalpy) is transferred to the compressor. By controlling the electric motor, the optimum speed for the compressor can be set throughout the engine map. Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiments shown and described below or limited to an article which would be limited in comparison with the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this shows in:

1 A - B is a schematic representation of the sequence of a two-stroke combustion process, Fig. 2A - D is a schematic representation of the sequence of a four-stroke combustion process,

3 is a schematic representation of a development of a loader arrangement according to the concept of the invention, a schematic representation of an alternative implementation according to the concept of the invention, 5 is a schematic representation of a flushing of a cylinder in two-stroke operation according to the concept of the invention,

Fig. 6 is a motor map.

FIGS. 1A and 1B show a schematic representation of the sequence of a two-stroke combustion process. In Fig. 1A, a cylinder 420 is shown, in which a in the direction of the cylinder axis of the cylinder 420 translationally movable piston 424 is arranged. The piston 424 is shown in the vicinity of a bottom dead center UT. According to the principle of reversing the head, gas, in particular a two-stroke charge air stream L2T, flows into the combustion chamber 432 formed essentially by a cylinder wall 422 of the cylinder 420 and the piston 424. The charge air L2T is conveyed into the combustion chamber 432 by at least one inlet valve 426E.

The two-stroke charge air flow L2T is previously compressed by a compressor 300, which is driven according to the concept of the invention, to a sufficiently high pressure for the two-stroke operation. At the same time displaced with the influx of the charge air stream L2T in the combustion chamber 432 located exhaust gas. This exhaust gas leaves the combustion chamber in the form of a two-stroke exhaust gas flow A2T through at least one exhaust valve 426A, which is arranged here on the upper side of the cylinder 420 in the vicinity of a top dead center OT

432nd

The process illustrated in FIG. 1A thus includes charging the combustion chamber 432 with charge air L2T and virtually simultaneously discharging the exhaust gas A2T. In Fig. 2B, the piston 424 is in the vicinity of the top dead center OT, that is, that the combustion chamber 432 has reached almost its minimum volume. This means that the charge air L2T which has previously flowed into the combustion chamber 432 has been compressed by the upward movement of the piston 424 and thus the reduction of the combustion chamber 432. The inlet valve 426E and the outlet valve 426A 426 are closed to prevent leakage of the charge air L2T. The illustrated state is practically the end of the compression process. By ignition ZUE of the compressed gas in the combustion chamber 432 of the piston 426 is then moved in the phase referred to as the working phase of the expanding gas down toward a bottom dead center UT. Practically when the bottom dead center UT is reached by the piston 424, the cycle starts again by the loading or ejecting operation shown in FIG. 1A.

FIGS. 2A to 2D show a schematic representation of the sequence of a four-stroke combustion process. FIG. 2A shows the process of loading in a cylinder 420. Due to the position of a piston 424 near bottom dead center UT, the combustion chamber 432 practically has its largest possible volume. A four-stroke charge air flow L4T flows, in particular by prior pressurization by a compressor 300 not shown here and / or by a negative pressure generated by the downward movement of the piston 424, through the open inlet valve 426E in the combustion chamber 432nd In contrast to the in FIG 1A illustrated two-stroke operation is in this case the exhaust valve 426 A closed.

In Fig. 2B, the piston 424 is near top dead center OT. The intake valve 426E and the exhaust valve 426A are closed; the gas which has flowed in the previous step, represented in FIG. 2A, is thus already compressed at the instant represented here. The state shown in Fig. 2B is practically the end of the compression. There is an ignition ZUE.

In Fig. 2C, the piston 424 is again at bottom dead center UT. This state is preceded by an expansion by the ignition ZUE of the compressed gas, which in turn has taken place following the final state of compression shown in FIG. 2B. The state shown in Fig. 2C thus represents practically the end of working or the working phase, in which in particular a drive movement of a motor 1200 is generated. In Fig. 2D, finally, the discharge of an exhaust gas, which has arisen during the previous expansion or ignition. For this purpose, the exhaust valve 426A is opened so that upon an upward movement of the piston 424 or at a reduction of the combustion chamber 432, the exhaust gas leaves the combustion chamber 432 in the form of a four-stroke exhaust stream A4T. FIG. 3 shows a schematic illustration of a development of a loader arrangement 100 according to the concept of the invention. In this case, the supercharger arrangement 100 has in particular a utility turbine 200 and a compressor 300. In particular, an exhaust gas flow A directed from an engine 1200 is conducted completely through the utility turbine 200, in which the energy of the exhaust gas is converted into kinetic energy, in particular into a first rotational movement RT. The loader assembly 100 further includes a clutch assembly 150. In the present case, the rotational movement generated by the utility turbine is transmitted to a turbine coupling 250 via a turbine output shaft 202, which is preferably designed as a hydrodynamic coupling. By means of the hydrodynamic coupling, in particular, speed jumps can be adjusted without jerking or jerk-reducing, and torsional vibrations can advantageously be damped. From the turbine clutch 250, the rotational movement is further transmitted via a power turbine transmission drive shaft 204 to a power turbine gearbox 280, which serves in particular the rotational speed adjustment of the rotational movement generated by the power turbine 200. The speed adjustment takes place in particular for reducing or reducing the generally higher speed of the power turbine 200 to a suitable for coupling into a crankshaft 400 of the engine 1200 speed. Typical ratios for translation or reduction are between 25 and 30.

From the utility turbine transmission 280, the reduced rotational motion is transmitted to the crankshaft 400 of the engine 1200. In this way, the energy recovered from the exhaust stream A is returned to the engine 1200 in mechanical form. More preferably, the utility turbine transmission 280 further includes a freewheel to inhibit power flow in the event that the speed of the utility turbine transmission input shaft 204 is less than the speed of the crankshaft 400. From the crankshaft 400 of the engine 1200, a compressor transmission 380 is further driven in accordance with the concept of the invention. The compressor gearbox 380 changes the rotational speed of the rotary motion emanating from the crankshaft 400 so that it is suitable for driving the compressor 300, in particular sufficiently high.

The corresponding translated rotational movement is then transmitted via a compressor transmission output shaft 304 from the compressor transmission 380 to a compressor clutch 350, which in turn provides a second rotational movement RV for the compressor 300, which is transmitted to the compressor via a compressor drive shaft. The compressor clutch 350 has, analogous to the turbine clutch 250, the advantage that speed jumps are aligned in particular smoothly and torsional vibrations are damped by the operation of a hydrodynamic coupling. In particular, it is achieved by a filling-controlled hydrodynamic coupling that the transmission capacity of the compressor clutch can be controlled or regulated by adjusting the level of a coupling fluid within a coupling space 258. In particular, in this way an optimum rotational speed of the compressor 300, which is optimal for an instantaneous operating state of the engine 1200, can be regulated.

The compressor 300, which in the present case is designed as a flow compressor, is mechanically driven in this way by the rotational movement of the crankshaft 400. Thus, the compressor 300 can advantageously compress a charge airflow L supplied to the engine 1200.

Furthermore, a device 900 for operating the internal combustion engine 1000 is shown schematically, which in the present case has a control and processing means 910. This control and processing means 910 is signal-connected to the turbine clutch 250, the utility turbine transmission 280, the compressor clutch 350, and the compressor transmission 380, as shown in dashed lines herein. In this way, the concept of the invention can be implemented, for example, in the sense of an automatic system or control circuit shown in this preferred embodiment. In particular, the rotational movements, that is, here the rotational movements RT and RV, can be adjusted according to this embodiment. These rotary movements RT and RV can be translated or reduced by activating the power turbine transmission 280 and / or the compressor transmission 380. Additionally or alternatively, the transmission of the rotational movement can be interrupted or used by activating the turbine clutch 250 and / or the compressor clutch 350.

Furthermore, the control and processor means 910 signal leading with a here only indicated, but not shown in detail, in particular parent control of the internal combustion engine 1000 in connection. It may additionally or alternatively be part of this to the method according to the concept of the invention, in particular the switching of Motors 1200 of the two-stroke operation in the four-stroke operation or the four-stroke operation in the two-stroke operation to implement.

Fig. 4 shows a schematic representation of an alternative implementation according to the concept of the invention. Shown is an internal combustion engine 1000 "with a supercharger arrangement 100", which has a utility turbine 200 "and a compressor 300". The utility turbine 200 "is acted upon by an exhaust gas flow A" coming from an engine 1200.

The kinetic energy or rotational movement RT generated in this way is transmitted via a generator drive shaft 212 to a turbine-side generator 220. This turbine-side generator 220 converts the kinetic energy into electrical energy, which is transmitted via a turbine-side generator line 221, in particular in the form of a turbine-side generator current 242, to a turbine controller 240.

In the turbine controller 240, the turbine-side generator current 242 is regulated in accordance with setpoint values 241, which originate in particular from a higher-level control, in particular an engine electronics. A turbine-side generator current 243 regulated in this manner is then transmitted via a turbine-side engine line 222 to a turbine-side engine 230. The latter is torque-transmittingly connected to a crankshaft 400 "of the engine 1200", so that a rotational movement RM generated by the turbine-side engine 230 can be used to drive the crankshaft 400 ", in particular to support the rotational movement RK of the crankshaft 400".

In contrast to the development shown in FIG. 3, therefore, no complete mechanical recovery of the exhaust gas energy takes place in the present case. Instead, by conversion to electrical energy, regulation, and subsequent reconversion to mechanical energy, electromechanical recovery of the exhaust energy occurs. The crankshaft 400 "is further connected according to the concept of the invention in this development torque transmitting with a compressor-side generator 224.

This compressor-side generator 224 converts the kinetic energy transmitted by the crankshaft 400 "in the form of a rotational movement into electrical energy, which is transmitted in particular in the form of a compressor-side generator current 246 via a compressor-side generator line 225 to a compressor controller 244 is the compressor-side generator current 246, according to set values 245 for the Compressor controller 244, regulated. Analogously to the turbine controller 240, the setpoint values 245 likewise originate in particular from a higher-level control, in particular an engine electronics.

A regulated compressor-side generator current 247 is then passed via a compressor-side motor line 226 to a compressor-side motor 234. This compressor-side motor 234 is torque-transmittingly connected to the compressor 300 "via a compressor drive shaft 312. Thus, by driving the compressor 300" through the compressor-side motor 234, a charge air flow L "supplied to the engine 1200" is compressed.

In contrast to the development shown in FIG. 3, in the present case a rotational movement from the crankshaft 400 "to the compressor 300" is not completely mechanical, but by a conversion of kinetic energy into electrical energy, a regulation, and a back conversion of electrical energy into kinetic energy, electromechanically transmitted. In the present case, this is therefore an electromechanical clutch arrangement 150 '. By such a development can be carried out by the conversion of kinetic energy into electrical energy and vice versa particularly advantageous both turbine-side and compressor side, a speed conversion. Furthermore, it is also possible to store the kinetic energy converted into electrical energy by means of suitable energy stores, in particular rechargeable batteries, and to migrate them back into kinetic energy at a later time.

5 further shows the principle of purging a cylinder 420, especially in two-stroke operation. For this purpose, the cylinder is shown in a state analogous to the state shown in Fig. 1A. The combustion chamber 432 is practically greatest possible, ie the piston 424 is located practically at the bottom dead center UT. A charge air flow L2T flows through at least one inlet valve 426E in the combustion chamber 432. A charge air flow L is compressed according to the concept of the invention by a compressor 300 and a charge air cooler 440 and a distributor not shown here in at least one feed channel 434 passed. In this case, according to the concept of the invention, the compressor 300 is not directly mechanically connected to the utility turbine 200, as would be the case with an exhaust-gas turbocharger in a figurative sense. In the present case, a torque-transmitted connection between the utility turbine 200 and the compressor 300 is essentially produced via a clutch arrangement 150, not shown here, and a crankshaft 400. As a result, in particular, there is the possibility that close torque-transmitting connection or open or in particular only partially produce a filling-controlled hydrodynamic coupling, in particular for influencing the speed of the transmitted rotary motion. Furthermore, there is the possibility to translate or reduce the rotational movement by not shown here transmission.

Furthermore, with the inflow of the charge air flow L2T into the combustion chamber 432 in accordance with the concept of a two-stroke engine, the simultaneous discharge of an exhaust gas flow A2T via at least one open exhaust valves 426 A and also an exhaust manifold 430 takes place. The exhaust gas flow A is still directed to the turbine 200, in FIG the remaining energy contained in the exhaust stream A is further converted into a mechanical rotary motion. However, this energy is lower compared to a discharged in four-stroke operation exhaust gas flow A4T. Fig. 6 shows schematically the characteristic diagram of a motor. On the ordinate here the effective mean pressure p _{me is} plotted, which in turn is proportional to the torque Md of the engine via the following relationship:

M, * 2π

7

H ¹

Here, VH is the total stroke volume of the engine and i the number of cycles per revolution (0.5 for four-stroke, 1 for two-stroke operation).

The abscissa shows the engine speed nMot. Furthermore, the isolines Bl - B7 respectively indicate operating points of the same effective engine power P _e . In the present case, the operating point Bl corresponds to an engine power of 10%, the operating point B2 to an engine power of 20%, the operating point B3 to an engine power of 30%, the operating point B4 to an engine power of 50%, and the operating point B5 to an engine power of 70% , In these

Operating points Bl - B5 is according to the concept of the invention at any time a switch to the 2-stroke operation possible or useful, in particular to increase the engine power in the short term and to reach an operating point in a further right upper area in the diagram shown here. The isolines B6 and B7 shown as solid lines show certain operating points of the engine. In this case, the isoline B6 corresponds to an engine power of 80% and the isoline B7 to an engine power of 100%. Such operating points are approached in particular in stationary operation, where operation in two-stroke operation is not advantageous. A two-stroke operation is therefore always useful if - especially in transient range - fast performance leaps are to be achieved. The area K further indicates the entire power range of the motor, which is limited by the limit G enclosing the power range K.

LIST OF REFERENCE NUMBERS

100, 100 "loader arrangement

150, 150 'coupling arrangement

200, 200 "power turbine

202 Turbine output shaft

204 power turbine transmission drive shaft

212 Generator drive shaft

220 turbine-side generator

221 Turbine-side generator line

222 Turbine-side motor cable

224 Compressor-side generator

225 Compressor-side generator line

226 Compressor-side motor cable

230 turbine-side engine

234 Compressor-side engine

240 turbine controllers

241 setpoints for the turbine controller

242 Turbine-side generator current

243 Regulated turbine-side generator current

244 Compressor controller

245 setpoint values for the compressor controller

246 Compressor-side generator current

247 Regulated compressor-side generator current

250 Turb entenkupp development

258 clutch room

280 turbines gearbox

300, 300 "compressor

302 Compressor drive shaft

304 Compressor transmission output shaft

312 Compressor drive shaft

350 compressor clutch

380 compressor gearbox

400, 400 "crankshaft 420 cylinders

422 cylinder wall

424 pistons

426 valve

426A exhaust valve

426E inlet valve

430 exhaust manifold

432 combustion chamber

434 feed channel

440 intercooler

900 device for operating an internal combustion engine

910 control and processor means

1000, 1000 "internal combustion engine

1200, 1200 "engine

A, A '' exhaust gas flow

A2T Cylinder exhaust gas flow in 2-stroke operation

A4T cylinder exhaust gas flow in 4-stroke operation

Bl - B7 Isolines with operating points of equal effective engine power

G Limit of the power range

K power range

L, L "charge air flow

L2T cylinder charge air flow in 2-stroke operation

L4T cylinder charge air flow in 4-stroke mode

OT top dead center

RK Rotational movement of the crankshaft

RM Rotary movement of the turbine-side engine

RT Rotary movement of the utility turbine, first rotational movement

RV Rotary movement for the compressor, Second rotary movement

UT lower dead center

ZUE ignition

Claims

A method of operating an internal combustion engine (1000, 1000 ") with an engine (1200, 1200") having a crankshaft (400, 400 "), wherein a charge air flow (L, L.) Supplied to the engine (1200, 1200") ") by means of a compressor (300, 300") via a second rotational movement (RV) compressed and a Nutzturbine (200, 200 ") for generating a first rotational movement (RT) with a out of the motor (1200, 1200") Exhaust gas stream (A, A ") is acted upon, characterized by the steps: in a first operating mode operating the internal combustion engine (1000, 1000") in four-stroke operation,

in a second operating mode operating the internal combustion engine (1000, 1000 ") in two-stroke operation, wherein

the crankshaft (400, 400 ") of the power turbine (200, 200") is drivable via the first rotary motion (RV), - the compressor (300, 300 ") of the crankshaft (400, 400") is drivable over the second rotary motion (RV) wherein the second rotary motion (RV) for the compressor (300, 300 ") may be different from the first rotary motion (RT) of the power turbine (200, 200").

2. The method of claim 1, further comprising the step of:

Switching from a four-stroke operation of the first operation mode to a two-stroke operation of the second operation mode.

3. The method according to claim 1 or 2, further comprising the step: Switching from a two-stroke operation of the second operation mode to a four-stroke operation of the first operation mode.

4. The method according to any one of the preceding claims, characterized in that the power turbine (200) via a turbine clutch (250) to the crankshaft (400) of the engine

(1200) can be coupled.

5. The method according to any one of the preceding claims, characterized in that the turbine clutch (250) is designed as a hydrodynamic coupling, in particular as a filling-controlled hydrodynamic coupling.

6. The method according to any one of the preceding claims, characterized in that the compressor (300) via a compressor clutch (350) to the crankshaft (400) of the engine (1200) can be coupled.

7. The method according to any one of the preceding claims, characterized in that the compressor clutch (350) is designed as a hydrodynamic coupling, in particular as a filling-controlled hydrodynamic coupling. 8. The method according to any one of the preceding claims, characterized in that the power turbine (200) further arranged via a power turbine transmission (280) between the turbine clutch (250) and crankshaft (400) with the crankshaft (400) can be coupled.

9. The method according to any one of the preceding claims, characterized in that the compressor (300) further comprises a compressor transmission (380) between the compressor clutch

(350) and crankshaft (400) arranged, with the crankshaft (400) can be coupled.

10. The method according to any one of the preceding claims, characterized in that when operating the internal combustion engine in the two-stroke operation, the cylinder (420) are flushed by a Kopfumkehrspülung.

11. A device (900) for operating an internal combustion engine (1000, 1000 ") with a motor (1200, 1200") and a loader arrangement (100, 100 "), wherein a charge air flow (L, L ") by means of at least one compressor (300, 300") compacted and at least one turbine (200, 200 ") can be acted upon by an exhaust gas flow (A, A") discharged from the engine (1200, 1200 "), configured to carry out a method according to one of claims 1 to 10 for operating an internal combustion engine ( 1000, 1000 "), wherein the crankshaft (400, 400") of the power turbine (200, 200 ") is drivable via the first rotational movement (RV), the compressor (300, 300") of the crankshaft (400, 400 ") is drivable via the second rotational movement (RV) wherein the second rotational movement (RV) for the compressor (300, 300") different from the first rotational movement (RT) of the power turbine (200, 200 ") can be adjusted. 12. Internal combustion engine (1000, 1000 ") with a motor (1200, 1200") and with a loader arrangement (100, 100 "), wherein the loader assembly (100, 100") comprises: a power turbine (200, 200 ") for conversion of energy of an exhaust gas flow (A, A ") of the engine (1200, 1200") into a rotary motion, a compressor (300, 300 ") for compressing a charge air flow (L, L") for the engine (1200, 1200 ") wherein the internal combustion engine (1000, 1000 ") is designed for carrying out a method according to one of claims 1 to 10 and / or a device (900) according to claim 11 for operating an internal combustion engine (1000, 1000").

13. internal combustion engine (1000, 1000 ') according to claim 12, characterized in that the coupling arrangement (150') is formed electromechanically, wherein a rotary motion (RT, RK) in a generator current (242, 243, 246, 247) or the generator current (242, 243, 246, 247) in a rotary motion (RM, RV) is convertible.

14. Internal combustion engine (1000, 1000 ') according to claim 12 or 13, characterized in that the power turbine (200 ") drives a generator (220).

15. Internal combustion engine (1000, 1000 ') according to any one of claims 12 to 14, characterized in that the crankshaft (400 ") of the motor (1200") drives a generator (224).