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

Abstract

A method for operating an internal combustion engine having an engine with a first number of cylinders and a second number of cylinders and a supercharger arrangement, wherein a charge air flow supplied to the engine is compressed by means of at least one compressor and at least one turbine is acted on by an exhaust gas flow discharged from the engine. In a main operating mode, the engine operates the first number of cylinders in two-stroke operation and the second number of cylinders in four-stroke operation. A scavenging gradient of the engine is greater for the cylinders operated in the two-stroke operation than for the cylinders operated in the four-stroke operation.

Claims

1. A method for operating an internal combustion engine, the internal combustion engine including an engine with a first number of cylinders and a second number of cylinders and a supercharger arrangement, the method comprising the steps of: supplying a charge air flow to the engine, the charge air being compressed by at least one compressor and at least one turbine that is acted on by an exhaust gas flow discharged from the engine; and operating the engine in a main operating mode that includes: operating the first number of cylinders in a two-stroke operation; and operating the second number of cylinders in a four-stroke operation, wherein a scavenging gradient is greater for the first number of cylinders operated in the two-stroke operation than for the second number of cylinders operated in the four-stroke operation, wherein a second exhaust gas flow of the second number of cylinders operated in the four-stroke operation is used for producing the scavenging gradient in the first number of cylinders operated in the two-stroke operation.

2. The method as claimed in claim 1, further comprising the steps of: operating the engine in a four-stroke operating mode by operating the first number of cylinders and the second number of cylinders in the four-stroke operation; and/or operating the engine in a two-stroke operating mode by operating the first number of cylinders and the second number of cylinders in the two-stroke operation.

3. The method as claimed in claim 2, further comprising the step of switching the engine over from the four-stroke operation of the four-stroke operating mode to the two-stroke operation of the two-stroke operating mode.

4. The method as claimed in claim 2, further comprising the step of switching the engine over from the two-stroke operation of the two-stroke operating mode to the four-stroke operation of the four-stroke operating mode.

5. The method as claimed in claim 1, wherein in the main operating mode, the first number of cylinders or at least one first cylinder or the second number of cylinders or at least one second cylinder is switched over from the four-stroke operation to the two-stroke operation.

6. The method as claimed in claim 1, wherein in the main operating mode, the first number of cylinders or at least one first cylinder or the second number of cylinders or the at least one second cylinder is switched over from the two-stroke operation to the four-stroke operation.

7. The method as claimed in claim 1, wherein when operating the internal combustion engine of a number of cylinders of the first and second number of cylinders in the two-stroke operation, one or more of the number of cylinders are scavenged by head loop scavenging.

8. The method as claimed in claim 1, wherein the first number of cylinders are arranged in a first cylinder bank and the second number of cylinders are arranged in a second cylinder bank.

9. The method as claimed in claim 1, wherein cylinders of the first number of cylinders and cylinders of the second number of cylinders are respectively arranged alternately next to one another.

10. The method as claimed in claim 1, further comprising the step of passing a first exhaust gas flow of the first number of cylinders directly past a high-pressure stage of the supercharger arrangement to a low-pressure stage of the supercharger arrangement.

11. The method as claimed in claim 10, further comprising the step of passing the second exhaust gas flow of the second number of cylinders to the high-pressure stage of the supercharger arrangement and subsequently to a low-pressure stage of the supercharger arrangement.

12. The method as claimed in claim 1, further comprising the step of passing a first exhaust gas flow of the first number of cylinders directly past the supercharger arrangement to an exhaust system, or a wastegate or the like.

13. The method as claimed in claim 1, further comprising the step of successively operating the internal combustion engine in a first operating phase and a second operation phase, wherein an assignment of a total number of cylinders to each of the first number of cylinders and the second number of cylinders for the first operating phase is the reverse of the assignment of the second operating phase.

14. A device for operating an internal combustion engine, comprising: an engine with a first number of cylinders and a second number of cylinders; a supercharger arrangement wherein a charge air flow is supplied to the engine, the charge air flow being compressed by at least one compressor and at least one turbine that is acted on by an exhaust gas flow discharged from the engine; control and processor means carrying out a method for controlling and regulating the internal combustion engine by executing the step of operating the internal combustion engine in a main operating mode, wherein the first number of cylinders of the engine are operated in a two-stroke operation and the second number of cylinders of the engine are operated in a four-stroke operation, wherein a scavenging gradient is greater for the first number of cylinders operated in the two-stroke operation than for the second number of cylinders operated in the four-stroke operation, wherein a second exhaust gas flow of the second number of cylinders operated in the four-stroke operation is used for producing the scavenging gradient in the first number of cylinders operated in the two-stroke operation.

15. An internal combustion engine, comprising: an engine with a first number of cylinders and a second number of cylinders; a supercharger arrangement with at least one low-pressure stage wherein a charge air flow supplied to the engine is compressed by at least one compressor and at least one turbine acted on by an exhaust gas flow discharged from the engine; and a control or processor carrying out the step of operating the internal combustion engine in a main operating mode, wherein the first number of cylinders are operated in a two-stroke operation and the second number of cylinders are operated in a four-stroke operation, wherein a scavenging gradient is greater for the first number of cylinders operated in the two-stroke operation than for the second number of cylinders operated in the four-stroke operation, wherein a second exhaust gas flow of the second number of cylinders operated in the four-stroke operation is used for producing the scavenging gradient in the first number of cylinders operated in the two-stroke operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows an internal combustion engine of a preferred embodiment of the present invention in a schematic representation;

(3) FIG. 2A shows a schematic representation of a sequence of a two-stroke combustion process;

(4) FIG. 2B shows a schematic representation of another sequence of the two-stroke combustion process of FIG. 2A;

(5) FIG. 3A shows a schematic representation of one sequence of a four-stroke combustion process, the sequence being sequentially represented in FIGS. 3A-3D;

(6) FIG. 3B shows another schematic representation of one sequence of a four-stroke combustion process, the sequence being sequentially represented in FIGS. 3A-3D;

(7) FIG. 3C shows yet another schematic representation of one sequence of a four-stroke combustion process, the sequence being sequentially represented in FIGS. 3A-3D;

(8) FIG. 3D shows still another schematic representation of one sequence of a four-stroke combustion process, the sequence being sequentially represented in FIGS. 3A-3D; and

(9) FIG. 4 shows an internal combustion engine of a further preferred embodiment of the present invention in a schematic representation.

(10) Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

(11) Referring now to the drawings, and more particularly to FIG. 1 there is shown an internal combustion engine 1000 with a gas flow control system 10 in a first embodiment of the invention. The gas flow control system 10 is arranged at the periphery of an engine 1200 for conducting gas, i.e. fresh air and exhaust gas. Engine 1200 has an inflow-side periphery and an outflow-side periphery. Engine 1200 is shown symbolically in the form of a large diesel engine and has a first cylinder bank B1 with a first gas delivery 3 and a second cylinder bank B2 with a second gas delivery 4.

(12) A gas flow control system 100 has an inflow-side gas supply 1 for supplying gas to an input side of engine 1200. Gas supply 1 has in the present case a fresh air section 11. Fresh air section 11 of gas supply 1 is initially formed by a raw air section 11.1 for taking in raw air with an air filter 180 ahead of a low-pressure compressor 172 with a downstream intercooler 178. In the present case, two raw air sections 11.1 and two low-pressure compressors 172 and two intercoolers 178 are provided.

(13) The two raw air sections 11.1 are brought together into a common charge air gap 11.2 ahead of a high-pressure compressor 162, which is adjoined by a high-pressure charge air section 11.3, which leads from the high-pressure compressor 162 to a charge air cooler 480. On the inflow side of charge air cooler 480 there is a supply-line separating means 190, by which the gas-conducting connection between a charge air section 11.3 and the charge air cooler 480 can be established or interrupted. On an outflow side of charge air cooler 480, there adjoins, in the present case, two cylinder charge air sections 11.4 of fresh air section 11, which establish a gas-conducting connection to cylinders 442, arranged on first cylinder bank B1 or cylinders 444 arranged on second cylinder bank B2.

(14) The compressors of the supercharger arrangement 100, to be specific the two low-pressure compressors 172 and the high-pressure compressor 162, are respectively driven by a turbine 164, 174 of the outflow-side gas discharge 2. For this purpose, two low-pressure turbines 174 in a low-pressure exhaust gas section 13.1 and a high-pressure turbine 164 in an intermediate exhaust gas section 13.3 are arranged between low-pressure turbines 174 and a high-pressure exhaust gas section 13.2 of exhaust gas line 13. An outflow-side gas discharge 2 adjoins on the outflow side of the high-pressure exhaust gas section 13.2 of line 13, which is connected to gas deliveries 3, 4. Gas deliveries 3, 4 are respectively connected on the outflow side of engine 1200 to cylinders 442, 444 of cylinder banks B1, B2, that is to say in the present case are arranged on an output side of engine 1200.

(15) Engine 1200 is operable according to the concept of the invention in four-stroke operation, in two-stroke operation or in a hybrid operation, that is to say with some cylinders in four-stroke operation and some other cylinders in two-stroke operation. For two-stroke operation, in particular a charge is provided in order to achieve sufficient scavenging, in particular head loop scavenging, of the cylinders.

(16) In the present illustration, all of the cylinders 442 of a first number Z1 of cylinders are arranged on the first cylinder bank B1. Furthermore, all of the cylinders 444 of a second number Z2 of cylinders are arranged on the second cylinder bank B2. Also possible of course are assignments different from this, as explained in more detail below for example in connection with FIG. 4.

(17) In the present case, internal combustion engine 1000 in a first main operating mode is explained. Here, cylinders 442 of first cylinder bank B1 are operated in two-stroke operation and the cylinders 444 of second cylinder bank B2 are operated in four-stroke operation. For carrying out hybrid operation, in the present case a first exhaust gas flow AG1 originating from cylinders 442 of first cylinder bank B1 and a second exhaust gas flow AG2 originating from cylinders 444 of second cylinder bank B2 are conducted separately. For this purpose, arranged on high-pressure exhaust section 13.2, which connects first gas delivery 3 and second gas delivery 4, are a first barrier separating means 196, which is closed for this purpose, and a second barrier separating means 198, which is open for this purpose. Furthermore, a first bypass separating means 192, arranged on first gas delivery 3, and a second bypass separating means 194, arranged on second gas delivery 4, provide the possibility of respectively passing exhaust gas flow AG1 or AG2, originating from the corresponding cylinder bank B1 or B2 directly, especially past a high-pressure stage 160 of supercharger arrangement 100, to low-pressure turbine 174 of low-pressure stage 170 of supercharger arrangement 100.

(18) In the present case, first bypass separating means 192 is open. In this way, first exhaust gas flow AG1 of cylinders 442 operated in two-stroke operation is passed via a first bypass line 13.4 directly to low-pressure exhaust gas section 13.3, and consequently advantageously achieves a low exhaust gas back pressure for cylinders 442 operated in two-stroke operation. From low-pressure exhaust gas section 13.3, first exhaust gas stream AG1 is passed directly to low-pressure turbines 174 of low-pressure stage 170. Both low-pressure turbines 174 are respectively connected via a low-pressure turbine shaft 176 for transmitting a rotational movement in each case to low-pressure compressor 172.

(19) Furthermore, second bypass separating means 194 is closed and second barrier separating means 198 is open, whereby second exhaust gas flow AG2 originating from cylinders 444 of second cylinder bank B2 is passed via high-pressure exhaust gas section 13.2 to high-pressure turbine 164 of high-pressure stage 160. This achieves the effect that second exhaust gas flow AG2, which has a higher exhaust gas pressure than first exhaust gas flow AG1 due to the four-stroke operation of cylinders 444, is used for acting on high-pressure turbine 164. High-pressure turbine 164, which is set in rotary motion by exhaust gas flow AG2, drives high-pressure compressor 162 via a high-pressure turbine shaft 166. Here, first barrier separating means 196 is closed and second barrier separating means 198 is open.

(20) Nevertheless, a reverse assignment of first number Z1 of cylinders and second number Z2 of cylinders is just as conceivable in a second main operating mode. By a corresponding closing of first bypass separating means 192 and an opening of second bypass separating means 194, first exhaust gas flow AG1 of cylinders 442, now operated in four-stroke operation, can consequently be passed to high-pressure turbine 164, and correspondingly second exhaust gas flow AG2 of cylinders 444, now operated in two-stroke operation, is passed via a second bypass line 13.5 directly to low-pressure turbine 174 of low-pressure stage 170. For this purpose, correspondingly first barrier separating means 196 is open and second barrier separating means 198 is closed.

(21) By way of separating means 192, 194, 196, 198, the assignment of cylinders 444 operated in four-stroke mode and cylinders 442 operated in two-stroke mode can consequently be reversed in any way desired, according to the concept of the invention, in particular to ensure uniform loading of all the cylinders and engine components connected to the cylinder.

(22) By the separation, and in particular the separate use of first exhaust gas flow AG1 and second exhaust gas flow AG2, an advantageous use, in particular a use corresponding to the different exhaust gas pressures of both exhaust gas flows, or recovery of the exhaust gas energy is consequently achieved.

(23) Alternatively, it is also conceivable not to pass the exhaust gas flows AG1, AG2 to a supercharger arrangement to make possible a scavenging gradient sufficient for two-stroke operation, but to divert them via a wastegate or the like.

(24) The following shows the switching states of the separating means in the two main operating modes described above:

(25) TABLE-US-00001 First main Second main operating mode operating mode First bypass Open Closed separating means 192 Second bypass Closed Open separating means 194 First barrier Closed Open separating means 196 Second barrier Open Closed separating means 198

(26) Now, additionally referring to FIG. 2A and FIG. 2B there is shown a schematic representation of the sequence of a two-stroke combustion process. Shown in FIG. 2A is a cylinder 420, in which there is arranged a piston 424 which is movable translationally in the direction of a cylinder axis of cylinder 420. In the representation of FIG. 2A, piston 424 is in the vicinity of a bottom dead center UT. According to the principle of head loop scavenging, gas, in particular a two-stroke charge air flow L2T, flows into combustion chamber 432 formed substantially by a cylinder wall 422 of cylinder 420 and piston 424. For this purpose, charge air L2T is conveyed through at least one inlet valve 426E into combustion chamber 432.

(27) For this, two-stroke charge air flow L2T is previously compressed by a compressor 162, which is not shown here, to a sufficiently high pressure for two-stroke operation. At the same time, exhaust gas located in combustion chamber 432 is displaced as charge air flow L2T flows in. This exhaust gas leaves combustion chamber 432 in the form of a two-stroke exhaust gas flow A2T through at least one outlet valve 426A, which in the present case is arranged on the upper side of cylinder 420 in the vicinity of a top dead center OT.

(28) The process represented in FIG. 2A thus involves a charging of the combustion chamber 432 with charge air L2T and, virtually at the same time, an expulsion of exhaust gas A2T.

(29) In FIG. 2B, piston 424 is in the vicinity of a top dead center, i.e. combustion chamber 432 has almost reached its minimum volume. This means that charge air L2T, which previously flowed into combustion chamber 432 has been compressed by the upward movement of piston 424, and consequently by the reduction in size of combustion chamber 432. Inlet valve 426E and outlet valve 426A are in this case closed, to prevent charge air L2T from escaping. The state shown represents virtually the end of the compression process.

(30) An ignition ZUE of the compressed gas in combustion chamber 432 then, in the phase which is also referred to as the working phase, causes piston 426 to be moved downward in the direction of a bottom dead center UT by the expanding gas. Virtually when the bottom dead center UT is reached by piston 424, the cycle begins anew by the charging and expulsion process shown in FIG. 2A.

(31) Now, additionally referring to FIGS. 3A to 3D there is shown a schematic representation of the sequence of a four-stroke combustion process. In FIG. 3A, the process of charging in cylinder 420 is shown. As a result of the position of piston 424 close to the bottom dead center UT, combustion chamber 432 has virtually its largest possible volume. A four-cycle charge air flow L4T flows through the open inlet valve 426E into combustion chamber 432, in particular as a result of prior pressurization by a compressor 162, not shown here, and/or as a result of a negative pressure generated by the downward movement of piston 424. By contrast with the two-stroke operation shown in FIG. 2A, in the present case outlet valve 426A is closed.

(32) In FIG. 3B, piston 424 is close to the top dead center OT. Inlet valve 426E and outlet valve 426A are closed; the gas which flowed in in the previous step, shown in FIG. 3A, is thus already compressed at the time shown in the present case. The state shown in FIG. 3B represents virtually the end of the compression cycle. An ignition ZUE then takes place.

(33) In FIG. 3C, piston 424 is again at the bottom dead center UT. This state has been preceded by an expansion caused by ignition ZUE of the compressed gas, which in turn took place following the end state of compression shown in FIG. 3B. The state shown in FIG. 3C thus represents virtually the end of the work or the working phase, in which a drive movement of engine 1200 is produced.

(34) In FIG. 3D, finally, the expulsion of an exhaust gas which has occurred during the preceding expansion or ignition takes place. For this purpose, outlet valve 426A is opened such that, when there is an upward movement of the piston 424 or when there is a reduction in the size of combustion chamber 432, the exhaust gas leaves the combustion chamber 432 in the form of a four-stroke exhaust gas flow A4T.

(35) Now, additionally referring to FIG. 4 there is shown an internal combustion engine 1000 according to a further preferred embodiment. Engine 1200 is likewise designed as a 12-cylinder engine. In particular as a difference from the embodiment shown in FIG. 1, engine 1200 shown here is charged in a single stage, to be precise via a compressor stage 170′. Here, cylinders A1 to A6 are arranged on a first cylinder bank B1 and cylinders B1 to B6 are arranged on a second cylinder bank B2. In the present case, the cylinders A1, A3, A5, B1, B3, B5 form a first number Z1′ of cylinders. Furthermore, the cylinders A2, A4, A6, B2, B4, B6 form a second number Z2′ of cylinders.

(36) According to the division into a first number Z1′ of cylinders and a second number Z2′ of cylinders, both first gas delivery 3 of first cylinder bank B1 and second gas delivery 4 of second cylinder bank B2 are in each case divided.

(37) Here, the cylinders of first number Z 1′, which are arranged in first cylinder bank B1, to be specific cylinders A1, A3 and A5, are connected in a gas-conducting manner via a first delivery branch 3.1 of first gas delivery 3 to a first turbine separating means 490.1.

(38) Furthermore, first delivery branch 3.1 of first gas delivery 3 can be connected in a gas-conducting manner via a first bypass separating means 492.1 directly to an exhaust gas section 413.

(39) Furthermore, the cylinders of first number Z 1′, which are arranged on second cylinder bank B2, to be specific the cylinders B1, B3 and B5, are connected in a gas-conducting manner via a first delivery branch 4.1 of second gas delivery 4 to first turbine separating means 490.1.

(40) Also first delivery branch 4.1 of second gas delivery 4 can be connected in a gas-conducting manner via first bypass separating means 492.1 directly to exhaust gas section 413.

(41) By closing first bypass separating means 492.1 and opening first turbine separating means 494.1, the exhaust gas flow AG1 originating from cylinders A1, A3, A5, B1, B3 and B5 of first number Z1′ can consequently be passed to one of the two turbines 174′. Turbines 174′ are thereby set in motion and, via a turbine shaft 176′ in each case, can drive a compressor 172′ for the purpose of compressing a charge air flow L. Charge air flow L is in turn supplied via a charge air cooler 480 to cylinders A1 to A6 and B1 to B6.

(42) By opening first bypass separating means 492.1 and closing first turbine separating means 494.1, exhaust gas flow AG1 originating from cylinders A1, A3, A5, B1, B3 and B5 of first number Z1′ can in turn be passed directly to exhaust gas section 413. This is particularly conducive to two-stroke operation, since a significantly lower exhaust back pressure is generated as a result of bypassing compressor stage 170′.

(43) The cylinders of second number Z2′, which are arranged on first cylinder bank B1, to be specific cylinders A2, A4 and A6, are connected in a gas-conducting manner via a second delivery branch 3.2 of first gas delivery 3 to a second turbine separating means 490.2. Furthermore, second delivery branch 3.2 of first gas delivery 3 can be connected in a gas-conducting manner via a second bypass separating means 492.2 directly to exhaust gas section 413.

(44) By analogy with first cylinder bank B1, the cylinders of second number Z2′, which are arranged on second cylinder bank B2, to be specific cylinders B2, B4 and B6, are connected in a gas-conducting manner via a second delivery branch 4.2 of second gas delivery 4 to second turbine separating means 490.2. Furthermore, second delivery branch 4.2 of second gas delivery 4 can likewise be connected in a gas-conducting manner via second bypass separating means 492.2 directly to exhaust gas section 413.

(45) By closing second bypass separating means 492.2 and opening second turbine separating means 490.2, exhaust gas flow AG2 originating from cylinders A2, A4, A6, B2, B4 and B6 of the second number Z2′ can consequently be passed to one of the two turbines 174′. Turbines 174′ are thereby set in motion and, via a turbine shaft 176′ in each case, drive a compressor 172′ for the purpose of compressing a charge air flow L. The charge air flow L is in turn supplied via a charge air cooler 480 to cylinders A1 to A6 and B1 to B6.

(46) By opening second bypass separating means 492.2 and closing second turbine separating means 494.2, in turn exhaust gas flow AG2 originating from cylinders A2, A4, A6, B2, B4 and B6 is passed directly to exhaust gas section 413. This is particularly conducive to two-stroke operation, since a significantly lower exhaust back pressure is generated as a result of bypassing compressor stage 170′.

(47) Consequently, it is advantageously possible for example to operate the cylinders of first number Z1′ in four-stroke operation, and the cylinders of second number Z2′ simultaneously in two-stroke operation. For this purpose, first turbine separating means 490.1 and second bypass separating means 492.2 are open, and second turbine separating means 490.2 and first bypass separating means 492.1 are closed.

(48) Conversely, in the present case it is equally possible to operate the cylinders of first number Z1′ in two-stroke operation, and the cylinders of second number Z2 in four-stroke operation. For this purpose, first turbine separating means 490.1 and second bypass separating means 492.2 are closed, and second turbine separating means 490.2 and first bypass separating means 492.1 are open.

(49) Also schematically shown is a device 900 for operating internal combustion engine 1000, which in the present case comprises a control and processor means 910. As illustrated in the present case by dashed lines, this control and processor means 910 is connected in a signal-conducting manner to separating means 490.1, 490.2, 492.1 and 492.2. 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, separating means 490.1, 490.2, 492.1 and 492.2 can be set in a way corresponding to the method according to the concept of the invention, that is to say be opened or closed. Furthermore, control and processor means 910 is in signal-conducting connection with a controller of internal combustion engine 1000 that is not shown here, in particular a higher-level controller. It may additionally or alternatively also be part of this, in order to implement the method according to the concept of the invention, in particular the switching over of the cylinders from two-stroke operation to four-stroke operation or from four-stroke operation to two-stroke operation.

(50) In the present embodiment, the shown assignment of cylinders to a first number Z1′ and a second number Z2′ is virtually alternately next to one another and distributed among both cylinder banks B1, B2. Nevertheless, it is of course conceivable to choose another grouping, such as for example the embodiment shown in FIG. 1 or another.

(51) While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

LIST OF REFERENCE SIGNS

(52) 1 Gas supply 2 Gas discharge 3 First gas delivery, gas delivery of the first cylinder bank 3.1 First delivery branch of the gas delivery of the first cylinder bank 3.2 Second delivery branch of the gas delivery of the first cylinder bank 4 Second gas delivery, gas delivery of the second cylinder bank 4.1 First delivery branch of the gas delivery of the second cylinder bank 4.2 Second delivery branch of the gas delivery of the second cylinder bank 10 Gas flow control system 11 Fresh air section 11.1 Raw air section 11.2 Common charge air section 11.3 High-pressure charge air section 11.4 Cylinder charge air section 13 Exhaust line 13.1 Low-pressure exhaust gas section 13.2 High-pressure exhaust gas section 13.3 Intermediate exhaust gas section 13.4 First bypass section 13.5 Second bypass section 100 Supercharger arrangement 160 High-pressure stage of the supercharger arrangement 162 High-pressure compressor 164 High-pressure turbine 166 High-pressure turbine shaft 170 Low-pressure stage of the supercharger arrangement 170′ Compressor stage 172 Low-pressure compressor 172′ Compressor 174 Low-pressure turbine 174′ Turbine 176 Low-pressure turbine shaft 176′ Turbine shaft 178 Intercooler 180 Air filter 190 Supply line separating means 192 First bypass separating means 194 Second bypass separating means 196 1st barrier separating means 198 2nd barrier separating means 413 Exhaust gas section 420 Cylinder 422 Cylinder wall 424 Piston 426 Valve 426A Outlet valve 426E Inlet valve 432 Combustion chamber 442 Cylinders of the first number of cylinders 444 Cylinders of the second number of cylinders 470 Exhaust system, exhaust 480 Charge air cooler 490.1 First turbine separating means 490.2 Second turbine separating means 492.1 First bypass separating means 492.2 Second bypass separating means 900 Device for operating an internal combustion engine 910 Control and processor means 1000 Internal combustion engine 1200 Engine AG Exhaust gas flow AG1 First exhaust gas flow, exhaust gas flow of the first number of cylinders AG2 Second exhaust gas flow, exhaust gas flow of the second number of cylinders A2T Cylinder exhaust gas flow in 2-stroke operation A4T Cylinder exhaust gas flow in 4-stroke operation B1 First cylinder bank B2 Second cylinder bank L Charge air flow L2T Cylinder charge air flow in 2-stroke operation L4T Cylinder charge air flow in 4-stroke operation OT Top dead center UT Bottom dead center Z1, Z1′ First number of cylinders, first cylinder Z2, Z2′ Second number of cylinders, second cylinder ZUE Ignition