DE102014218656A1 - Method for operating a partially switched off internal combustion engine and internal combustion engine for carrying out such a method - Google Patents

Abstract

Method for operating a partially switched-off internal combustion engine (7) with min. two cylinders arranged in series (1, 2, 3, 4), in which - each cylinder (1, 2, 3, 4) comprises a piston, min. an outlet and min. has an inlet opening, - min. two cylinders (1, 2, 3, 4) are configured in such a way that these min. two groups each with min. a cylinder (1, 2, 3, 4) form, wherein the min. a cylinder (1, 4) of a first group is a cylinder (1, 4) which is also in operation during partial deactivation of the internal combustion engine (7) and the at least one cylinder (2, 3) of a second group is a load - dependent switchable cylinder (2, 3 ), and - min. a valvetrain comprising valve means is provided for controlling a four-cycle charge cycle, each valve being movable along a longitudinal axis between a valve closed position and a valve open position to complete a maximum valve lift, the exhaust gas of an in-service cylinder (1, 4) of the first group is discharged during the charge exchange from this exhaust gas supplying cylinder (1, 4) and via overflow (5a, 5b) in a deactivated cylinder (2, 3) of the second group during the charge cycle of this exhaust gas receiving cylinder (2, 3) is introduced, wherein exhaust gas-receiving deactivated cylinder (2, 3) of the second group, a cylinder (2, 3) preceding in the ignition sequence is used, and a cylinder (1, 4) following in the ignition sequence as exhaust-supplying operating cylinder (1, 4) of the first group is used and in the overflow channel (5a, 5b) min. a shut-off is provided.

Description

• – jeder Zylinder einen Kolben umfasst, der im Betrieb der Brennkraftmaschine zwischen einem unteren Totpunkt (UT) und einem oberen Totpunkt (OT) oszilliert,
• – jeder Zylinder mindestens eine Auslassöffnung aufweist, an die sich eine Abgasleitung zum Abführen der Abgase via Abgasabführsystem anschließt,
• – jeder Zylinder mindestens eine Einlassöffnung aufweist, an die sich eine Ansaugleitung zum Zuführen von Ladeluft via Ansaugsystem anschließt,
• – mindestens zwei Zylinder in der Art konfiguriert sind, dass diese mindestens zwei Gruppen mit jeweils mindestens einem Zylinder bilden, wobei der mindestens eine Zylinder einer ersten Gruppe ein auch bei Teilabschaltung der Brennkraftmaschine in Betrieb befindlicher Zylinder ist und der mindestens eine Zylinder einer zweiten Gruppe als lastabhängig schaltbarer Zylinder ausgebildet ist, und
• – mindestens ein Ventile umfassender Ventiltrieb zum Steuern eines vier Takte umfassenden Ladungswechsels vorgesehen ist, wobei jedes Ventil entlang einer Längsachse zwischen einer Ventilschließstellung und einer Ventiloffenstellung unter Vollführung eines maximalen Ventilhubs bewegbar ist.

The invention relates to a method for operating a partially switched off internal combustion engine having at least two cylinders arranged in series, in which

• Each cylinder comprises a piston which, during operation of the internal combustion engine, oscillates between a bottom dead center (UT) and a top dead center (TDC),
• Each cylinder has at least one outlet opening adjoined by an exhaust pipe for discharging the exhaust gases via the exhaust gas removal system,
• Each cylinder has at least one inlet opening adjoined by an intake line for supplying charge air via the intake system,
• - At least two cylinders are configured in such a way that they form at least two groups each having at least one cylinder, wherein the at least one cylinder of a first group is also in partial deactivation of the internal combustion engine in operation cylinder and the at least one cylinder of a second group as load-dependent switchable cylinder is formed, and
• - Valve drive comprising at least one valve is provided for controlling a charge cycle comprising four cycles, wherein each valve is movable along a longitudinal axis between a valve closed position and a valve open position under full control of a maximum valve lift.

Furthermore, the invention relates to an internal combustion engine for carrying out such a method.

An internal combustion engine of the type mentioned is used as a motor vehicle drive. In the context of the present invention, the term internal combustion engine includes diesel engines and gasoline engines, but also hybrid internal combustion engines, which use a hybrid combustion process, and hybrid drives, which in addition to the internal combustion engine comprise an electric motor which can be electrically connected to the internal combustion engine, which receives power from the internal combustion engine or as switchable auxiliary drive additionally delivers power.

In the development of internal combustion engines, it is a fundamental goal to minimize fuel consumption, with an improved overall efficiency in the foreground of the efforts.

The fuel consumption and thus the efficiency, especially in gasoline engines, d. H. in spark-ignition internal combustion engines. The reason for this lies in the basic working method of the gasoline engine. The load control is usually carried out by means of a throttle valve provided in the intake system. By adjusting the throttle, the pressure of the intake air behind the throttle valve can be reduced more or less. The farther the throttle is closed, d. H. the more this obstructs the intake system, the higher the pressure loss of the intake air across the throttle and the lower the pressure of the intake air downstream of the throttle and before the intake into the at least two cylinders, d. H. Combustion chambers. With a constant combustion chamber volume, the air mass, d. H. the quantity will be set. This also explains why the quantity control proves to be disadvantageous especially in part-load operation, because low loads require high throttling and pressure reduction in the intake system, whereby the charge exchange losses increase with decreasing load and increasing throttling.

In order to reduce the losses described, various strategies have been developed for de-throttling a spark-ignited internal combustion engine.

One approach to dethrottling the gasoline engine is, for example, an Otto engine working method with direct injection. The direct injection of the fuel is a suitable means for realizing a stratified combustion chamber charge. The direct injection of the fuel into the combustion chamber thus allows within certain limits a quality control of the gasoline engine. The mixture formation takes place by the direct injection of the fuel in the cylinders or in the air in the cylinders and not by external mixture formation, in which the fuel is introduced into the intake system in the intake air.

Another way to optimize the combustion process of a gasoline engine, is the use of an at least partially variable valve train. In contrast to conventional valve trains, in which both the stroke of the valves and the control times are not variable, these parameters influencing the combustion process and thus the fuel consumption can be varied more or less by means of variable valve trains. Throttle-free and thus lossless load control is already possible if the closing time of the intake valve and the intake valve lift can be varied. The mixture mass or charge air mass flowing into the combustion chamber during the intake process is then not controlled by means of a throttle valve, but via the intake valve stroke and the opening duration of the intake valve. However, variable valve trains are very cost-intensive and therefore often unsuitable for serial installation.

Another solution for dethrottling a gasoline engine offers the cylinder deactivation, ie the shutdown of individual cylinders in certain load ranges. The efficiency of the gasoline engine in part-load operation can be improved by such a partial shutdown, because the shutdown of a cylinder of a multi-cylinder internal combustion engine increases the load of the remaining still operating cylinders at constant engine power, so that the throttle for introducing a larger air mass in this cylinder can be opened or must be, which overall a Entdrosselung the internal combustion engine is achieved. The continuously operating cylinders operate during partial shutdown in the area of higher loads, where the specific fuel consumption is lower. The load collective is shifted to higher loads.

The further operated during the partial shutdown cylinder also have due to the larger air mass supplied or mixture mass improved mixture formation.

Further efficiency advantages result from the fact that a deactivated cylinder as a result of the lack of combustion no wall heat losses generated as a result of heat transfer from the combustion gases to the combustion chamber walls.

Although diesel engines, d. H. self-igniting internal combustion engines, due to the applied quality control higher efficiency, d. H. have a lower fuel consumption than gasoline engines, in which the load - as described above - is set by throttling or quantity control on the filling of the cylinder, there is room for improvement in diesel engines and improvement in terms of fuel consumption and efficiency.

A concept for reducing fuel consumption is also the cylinder deactivation in diesel engines, d. H. the shutdown of individual cylinders in certain load ranges. The efficiency of the diesel engine in part load operation can be improved by a partial shutdown, d. H. be increased, because the shutdown of at least one cylinder of a multi-cylinder internal combustion engine increases at constant engine power even in the diesel engine, the load of the remaining operating cylinders, so that these cylinders operate in areas of higher loads, in which the specific fuel consumption is lower. The load collective in part-load operation of the diesel engine is shifted to higher loads.

With regard to the wall heat losses, the same advantages result as in the gasoline engine, for which reason reference is made to the corresponding explanations.

The partial shutdown in diesel engines should also prevent the fuel-air mixture under the quality scheme with decreasing load by reducing the amount of fuel used too much.

The multi-cylinder internal combustion engines with partial deactivation described in the prior art and the associated methods for operating these internal combustion engines nevertheless have clear potential for improvement, as will be briefly explained below.

Is in an internal combustion engine for the purpose of partial shutdown, the fuel supply to the turn-off cylinders prevented, d. H. If the associated valve drive of this cylinder is not deactivated or can not be deactivated, the deactivated cylinders continue to participate in the charge exchange. The charge cycle losses generated thereby by the deactivated cylinders reduce the improvements in fuel consumption and efficiency achieved by the partial shutdown and counteract these, so that the benefit of the partial shutdown is at least partially lost, ie. H. the partial shutdown in the sum actually brings a less significant improvement than would be possible.

In practice, it is often not expedient to remedy the adverse effects described above in that switchable valve trains are provided because switchable valve trains such as variable valve trains are costly and are not always suitable for mass production. To completely deactivate the valvetrain of the switchable cylinders during partial shutdown, d. H. to leave the intake and exhaust valves in the closed position, would have the disadvantage that sets in the deactivated cylinders after a few working games as a result of the blow-by a negative pressure, the oil promotes the combustion chamber, which burned when reconnecting the deactivated cylinder or unburned enters the exhaust system and significantly increases pollutant emissions.

In addition, switchable valve trains would result in turbocharged supercharged by exhaust gas turbochargers to further problems, since the turbine of an exhaust gas turbocharger is to be interpreted to a certain amount of exhaust gas and thus to a certain number of cylinders. When the valve train of a deactivated cylinder is deactivated, the total mass flow through the cylinders of the internal combustion engine decreases due to the lack of mass flow through the deactivated cylinders. The guided by the turbine Exhaust mass flow decreases and with this the turbine pressure ratio. This has the consequence that the boost pressure ratio also decreases, ie, the boost pressure drops, and only a little fresh air or charge air is supplied to the further operating cylinders or can be supplied. The low charge air flow can also cause the compressor to operate beyond the surge line.

The effects described above lead to a limitation of the applicability of the partial shutdown, namely to a limitation of the load range in which the partial shutdown can be used. The reduced amount of charge air supplied to the cylinders in operation during the partial shutdown reduces the effectiveness or quality of the combustion and adversely affects the fuel consumption and the pollutant emissions.

The charge pressure at partial shutdown and thus the still in operation cylinders supplied charge air quantity could be increased, for example, by a small design of the turbine cross-section and simultaneous Abgasabblasung, whereby the relevant for a partial shutdown load range would be extended again. However, this approach has the disadvantage that the charging behavior is insufficient when all cylinders are operated.

The charge pressure at Teilabschaltung and thus the still in operation cylinders supplied charge air quantity could also be increased by the fact that the turbine is equipped with a variable turbine geometry, which allows an adjustment of the effective turbine cross section to the current exhaust gas mass flow. At the same time, however, the exhaust gas back pressure in the exhaust gas removal system upstream of the turbine would increase, which in turn leads to higher charge exchange losses in the cylinders still in operation.

Concepts are also known from the prior art in which a shut-off element is provided in the exhaust gas removal system of a cylinder switched off for discharging the exhaust gases, wherein optionally the cylinder-related exhaust gas by means of return line, which from the Abgasabführsystem upstream of the Damping branches off and opens into the intake of the switchable cylinder, can be returned or will.

Concepts are also known from the prior art, in which a shut-off element is provided in the intake system of a load-dependent switchable cylinder, which blocks the intake system of the deactivated cylinder for supplying charge air in partial shutdown. Also, a return line can be provided, is removed with the exhaust gas from the Abgasabführsystem and returned to the suction side in the intake system of the deactivated cylinder downstream of the shut-off.

Like switchable valve trains, the latter two concepts are associated with additional costs. In addition, significant modifications of the Abgasabführsystems and / or the intake system are required. In addition, the problems discussed in connection with switchable valve trains are not or only partially solved.

In view of the foregoing, it is an object of the present invention to provide a method of operating a partially cut-off internal combustion engine having at least two cylinders arranged in series according to the preamble of claim 1, which improves the partial shutdown.

Another object of the present invention is to provide an internal combustion engine for carrying out such a method.

• – jeder Zylinder einen Kolben umfasst, der im Betrieb der Brennkraftmaschine zwischen einem unteren Totpunkt (UT) und einem oberen Totpunkt (OT) oszilliert,
• – jeder Zylinder mindestens eine Auslassöffnung aufweist, an die sich eine Abgasleitung zum Abführen der Abgase via Abgasabführsystem anschließt,
• – jeder Zylinder mindestens eine Einlassöffnung aufweist, an die sich eine Ansaugleitung zum Zuführen von Ladeluft via Ansaugsystem anschließt,
• – mindestens zwei Zylinder in der Art konfiguriert sind, dass diese mindestens zwei Gruppen mit jeweils mindestens einem Zylinder bilden, wobei der mindestens eine Zylinder einer ersten Gruppe ein auch bei Teilabschaltung der Brennkraftmaschine in Betrieb befindlicher Zylinder ist und der mindestens eine Zylinder einer zweiten Gruppe als lastabhängig schaltbarer Zylinder ausgebildet ist, und
• – mindestens ein Ventile umfassender Ventiltrieb zum Steuern eines vier Takte umfassenden Ladungswechsels vorgesehen ist, wobei jedes Ventil entlang einer Längsachse zwischen einer Ventilschließstellung und einer Ventiloffenstellung unter Vollführung eines maximalen Ventilhubs bewegbar ist, das dadurch gekennzeichnet ist, dass
• – Abgas eines in Betrieb befindlichen Zylinders der ersten Gruppe während des Ladungswechsels aus diesem abgasliefernden Zylinder abgeführt wird und via Überströmkanal in einen abgeschalteten Zylinder der zweiten Gruppe während des Ladungswechsels dieses abgasempfangenden Zylinders eingeleitet wird, wobei als abgasempfangender abgeschalteter Zylinder der zweiten Gruppe ein in der Zündfolge vorangehender Zylinder verwendet wird und als abgasliefernder in Betrieb befindlicher Zylinder der ersten Gruppe ein in der Zündfolge folgender Zylinder verwendet wird und in dem Überströmkanal mindestens ein Absperrelement vorgesehen ist.

The first object is achieved by a method for operating a partially switched off internal combustion engine having at least two cylinders arranged in series, in which

• Each cylinder comprises a piston which, during operation of the internal combustion engine, oscillates between a bottom dead center (UT) and a top dead center (TDC),
• Each cylinder has at least one outlet opening adjoined by an exhaust pipe for discharging the exhaust gases via the exhaust gas removal system,
• Each cylinder has at least one inlet opening adjoined by an intake line for supplying charge air via the intake system,
• - At least two cylinders are configured in such a way that they form at least two groups each having at least one cylinder, wherein the at least one cylinder of a first group is also in partial deactivation of the internal combustion engine in operation cylinder and the at least one cylinder of a second group as load-dependent switchable cylinder is formed, and
• - Valve drive comprising at least one valve is provided for controlling a charge cycle comprising four cycles, wherein each valve is movable along a longitudinal axis between a valve closed position and a valve open position under full control of a maximum valve lift, characterized in that
• - Exhaust gas of an operating cylinder of the first group is discharged during the charge exchange from this exhaust gas supplying cylinder and is introduced via overflow into a deactivated cylinder of the second group during the charge cycle of this exhaust gas receiving cylinder, as exhaust-receiving deactivated cylinder of the second group in the firing order the preceding cylinder is used and is used as the exhaust gas in operating cylinder of the first group, a cylinder following in the firing order and in the overflow at least one shut-off element is provided.

In the method according to the invention for operating a partially switched-off internal combustion engine, exhaust gas of an operating cylinder is supplied to a deactivated cylinder during partial shutdown via overflow channel.

In the present invention, the exhaust gas-supplying in-service cylinder is also referred to as the exhaust gas-supplying cylinder, whereas the cylinder which receives the exhaust gas is also referred to as the exhaust gas-receiving cylinder. Each cylinder of the first group which is also in operation when the internal combustion engine is partially switched off can serve as an exhaust gas supplying cylinder and each cylinder of the second group deactivated during partial shutdown can function as an exhaust gas receiving cylinder.

In the present case, the switchable cylinders do not necessarily have to be equipped with switch-off valve drives. Rather, according to the invention, the deactivated cylinders can continue to take part in the charge exchange if, for example, the overflow channel leads from the outlet side of an exhaust-supplying cylinder to the inlet side of a deactivated cylinder. The associated valvetrain of the deactivated cylinder can be operated further and does not have to be switched off together with the cylinders.

When the cylinder is switched off, the exhaust gas of a cylinder in operation and less or no charge air is supplied to the intake cylinder via an intake system, which reduces the charge cycle losses of the deactivated cylinder.

It should also be borne in mind that with the release of an overflow channel, the exhaust gases from an in-service cylinder of the internal combustion engine due to the high pressure levels prevailing in the cylinder towards the end of combustion and the associated high pressure difference between the operating exhaust gas cylinder and the deactivated exhaust gas receiving cylinder Flow at high speed through the overflow into the deactivated exhaust gas receiving cylinder. This pressure-driven transfer process is accompanied by a pressure peak, which can provide an overpressure or pressure increase even in the deactivated cylinder, prevents or complicates the supply of charge air and in individual cases leads to a torque is generated even in the deactivated cylinder. The latter supports the objective associated with the partial shutdown, namely to increase the efficiency of the internal combustion engine. It is therefore also advantageous to perform the overflow as small as possible or short.

The passage of the exhaust gas via overflow is inventively supported by the fact that as a cylinder receiving the exhaust gas in the ignition sequence is used as the exhaust-receiving cylinder and as an exhaust gas in operation cylinder in the following firing order cylinder.

Two cylinders following each other in the firing order have the least offset in terms of their work processes and are therefore suitable for the transfer of exhaust gas from one cylinder to the other cylinder, ie. H. from the cylinder following in the firing order to the cylinder preceding in the firing order. In a four-cylinder in-line engine whose cylinders are operated with the ignition sequence 1-3-4-2, for example, the fourth cylinder offers to deliver exhaust gas for the third cylinder preceding in the ignition sequence. While the fourth cylinder supports the passage of the exhaust gas through an upward stroke of the piston in the context of a Ausschiebetakt, the third cylinder simultaneously sucks the exhaust gas by a downward stroke movement of the piston in the context of an intake stroke.

The deactivated cylinders pump the transferred exhaust gas as a result of the stroke movement of the piston during the Ausschiebetaktes in the manner of a piston working machine in the Abgasabführsystem, where it can be used in the future in an optionally provided turbine for energy.

By passing hot exhaust gas through the deactivated cylinders during partial shutdown, these cylinders can not cool. This has advantages in terms of pollutant emissions, in particular with regard to the emissions of unburned hydrocarbons, since the deactivated cylinders again reach or have their operating temperature immediately after completion of the partial shutdown.

Although the introduction of hot exhaust gas into the deactivated cylinders does not directly increase the mass flow through the internal combustion engine, but for supercharged internal combustion engines with turbocharger turbocharger indirectly benefits. In contrast to the concepts described in the prior art, in which the exhausted cylinders only charge air is supplied during the partial shutdown, with the inventive introduction of hot exhaust gas in the deactivated cylinder, a higher exhaust gas temperature and a higher exhaust gas pressure in the Abgasabführsystem located in the exhaust gas generated. Both result in a higher exhaust gas enthalpy, which is largely determined by the exhaust gas pressure and the exhaust gas temperature. The higher exhaust gas enthalpy, ie the larger exhaust gas energy, which is available at the turbine of an exhaust gas turbocharger, leads to an increase of the boost pressure and thus the charge air quantity, which is why more charge air can be supplied to the cylinders in operation. This extends the scope of partial shutdown, namely the load range in which the partial shutdown can be used, and improves the quality of the combustion and thus the fuel consumption and emission behavior of the internal combustion engine. In addition, arranged in Abgasabführsystem exhaust aftertreatment achieve faster due to the hotter exhaust gases their operating temperature or light-off.

There are also advantages over concepts in which exhaust gas is supplied to the deactivated cylinders via the return line during partial deactivation, since the exhaust gas conducted in accordance with the invention is hotter than the exhaust gas recirculated by means of external exhaust gas recirculation. This circumstance is important and advantageous, since the temperature significantly determines the exhaust gas enthalpy.

With the method according to the invention, the first object underlying the invention is achieved, namely a method for operating a partially switched-off internal combustion engine according to the preamble of claim 1, which improves the partial shutdown.

Further advantageous embodiments of the method according to the invention are described in accordance with the subclaims.

Embodiments of the method in which the ignition of the at least one cylinder in operation is initiated by means of self-ignition are advantageous.

The above process variant relates to methods in which the combustion is initiated by means of auto-ignition, and thus also on working methods, such as are commonly used in diesel engines.

It is also possible to use a hybrid combustion process with auto-ignition for operating a gasoline engine, for example the so-called HCCI process, which is also referred to as a space ignition process or as a CAI process. This method is based on a controlled auto-ignition of the fuel supplied to the cylinder. Here, the fuel - as in a diesel engine - under excess air, so superstoichiometric, burned. The lean-burn gasoline engine has comparatively low nitrogen oxide emissions due to the low combustion temperatures and also no soot emissions due to the lean mixture. In addition, the HCCI process leads to a high thermal efficiency. The fuel can be introduced both directly into the cylinder and into the intake manifold.

However, embodiments of the method in which the ignition of the at least one cylinder in operation is initiated by means of spark ignition are also advantageous.

Advantageous in this context are embodiments of the method in which each cylinder is equipped to initiate a spark ignition with a spark plug, which serves as an ignition device, wherein the ignition device of the at least one switchable cylinder is preferably deactivated at shutdown.

The above method variant relates to the application of the method in a spark-ignited internal combustion engine, for example a direct-injection spark-ignition engine, the cylinders of which are each equipped with an ignition device for initiating spark ignition.

Embodiments of the method are advantageous in principle in which the spark ignition of the deactivatable cylinder is deactivated during partial shutdown.

In principle, and in particular in the case of auto-ignition methods, embodiments in which the fuel supply to the deactivatable cylinders is deactivated during partial deactivation are advantageous.

Embodiments of the method in which in each case an in-use cylinder and a deactivated cylinder are combined to form a charge-change group are advantageous, with exhaust gas being introduced from the cylinder in operation into the deactivated cylinder.

In the present case, the exhaust gas of exactly one cylinder is transferred to exactly one other cylinder, ie a specific assignment of two cylinders is made. Make two cylinders each a so-called charge change group. Compared to concepts in which an exhaust gas supplying cylinder more than one exhaust gas-receiving cylinder, for example, two or three other cylinders, supplied with exhaust gas, there are advantages.

If only one cylinder receives the exhaust gas, the - preferably pressure-driven - transfer operation can advantageously be used to generate an overpressure or increase in pressure in the deactivated cylinder. In this way, the supply or the suction of charge air can be effectively counteracted and a force exerted on the piston in the deactivated cylinder to generate a torque.

The exhaust gas in the cylinder, under pressure and a specific cylinder volume filling exhaust gas is transferred into a comparably large volume, namely the combustion chamber of the exhaust gas-receiving cylinder. The exhaust energy can be used better than when the exhaust gas is transferred into several cylinders and thus under pressure reduction in a much larger volume, namely in a multiple combustion chambers comprehensive volume.

The same considerations lead to the smallest possible or short executed overflow is particularly advantageous.

Therefore, embodiments of the method are advantageous in this context, in which two adjacent cylinders are combined to form a charge exchange group. In that case, the overflow channel can be particularly short and thus small in volume.

For operating a partially switched-off internal combustion engine, in which the exhaust pipes of the two cylinders of a charge exchange group merge to form a common exhaust pipe to form an exhaust manifold, are advantageous variants of the method, which are characterized in that the Abgasabführsystem the at least two cylinders is used as overflow.

In the present case, the Abgasabführsystem - at least - shared, d. H. at least parts of the overflow channel are formed by the already existing Abgasabführsystem. Optionally, the entire overflow channel is formed by the Abgasabführsystem, d. H. Parts of the Abgasabführsystems be used as overflow or misappropriated.

Embodiments of the method are advantageous in which the at least one inlet opening of the at least one operating cylinder is operated with partial switching off during the charge change with unchanged control times.

Embodiments of the method are advantageous in which the at least one outlet opening of the at least one operating cylinder is operated with partial switching off during the charge change with unchanged control times.

This variant ensures that the cylinders of the first cylinder group, which are still in operation at partial shutdown, do not have to be equipped with variable valve drives which are cost-intensive and therefore unsuitable for series production.

Embodiments of the method are advantageous in which the at least one inlet opening of the at least one load-dependent switchable cylinder is kept closed during partial shutdown. For this purpose, the load-dependent switchable cylinder of the second cylinder group must be equipped at least on the inlet side with disconnectable valve trains.

The above process variant requires that the transfer passage from the exhaust side of an exhaust gas supplying cylinder to the exhaust side of a deactivated cylinder, i. H. the transfer of exhaust gas takes place here on the outlet side. When the cylinder is switched off, only an exhaust gas from an operating cylinder and no charge air via the intake system are supplied to a deactivated cylinder.

Embodiments of the method are advantageous in which at least one outlet opening of each load-dependent switchable cylinder is operated with partial switching off with changed control times.

For this purpose, the load-dependent switchable cylinder of the second cylinder group must be equipped at least on the outlet side with variable valve trains with which the timing of the at least one outlet opening of the exhaust gas receiving cylinder can be changed, d. H. a shift of the opening time or closing time of this outlet opening can be made to early or late.

In this connection, embodiments of the method are advantageous in which the at least one outlet opening of the load-dependent switchable cylinder of a charge exchange group is opened when the at least one outlet opening of the cylinder in operation of this charge change group is opened.

Frequently, however, an outlet opening of the load-dependent switchable exhaust-gas-receiving cylinder can not be opened in accordance with the above process variant, ie simultaneously with an outlet opening of the exhaust gas cylinder in operation, since there is a risk that the piston of the exhaust-receiving cylinder near the top dead center with the associated exhaust valve in Touch comes, ie collides.

Therefore, embodiments of the method are also advantageous in which the at least one outlet opening of the load-dependent switchable cylinder of a charge change group is opened later than the at least one outlet opening of the cylinder in operation of this charge change group.

Embodiments of the method are advantageous in which the at least one outlet opening of the load-dependent switchable cylinder of a charge change group is closed when the cylinder-associated piston is on the way from bottom dead center (UT) to top dead center (TDC). Then can be adjusted with the closing time of the exhaust port, the exhaust gas amount, which is included in the exhaust gas receiving cylinder, d. H. remains to be subsequently compressed and to relax in the subsequent expansion phase in the cylinder again.

In the present case, it is not desirable to introduce as much exhaust gas as possible into the exhaust-gas-receiving cylinder and to enclose it in this. Rather, a part of the exhaust gas introduced into the exhaust-gas-receiving cylinder can be pushed out again by means of pistons. The remaining amount of exhaust gas in the cylinder should be such that a vacuum or negative pressure in the exhaust gas receiving cylinder is avoided or reduced until the next opening.

In this context, embodiments of the method are advantageous in which the at least one outlet opening of the load-dependent switchable cylinder of a charge change group 30 to 80 ° CA before top dead center (TDC) is closed, preferably 30 to 60 ° CA before top dead center (TDC) or 40 to 50 ° CA before top dead center (TDC).

Embodiments of the method in which the outlet valve belonging to the at least one outlet opening of the load-dependent switch cylinder is also kept open while maintaining a reduced valve lift for a predefinable crank angle range are advantageous if the cylinder-associated piston is on its way from bottom dead center (UT ) to top dead center (TDC).

Embodiments of the method are advantageous in which the at least one outlet opening of the load-dependent switchable cylinder of a charge change group is opened again before the at least one outlet opening of the cylinder in operation of this charge change group is opened again.

The transferred into the exhaust-receiving cylinder and remaining in this cylinder amount of exhaust gas should be pushed out by means of pistons and discharged via Abgasabführsystem to again introduce the next working cycle hot exhaust gas in the deactivated cylinder or can pass.

Therefore, embodiments of the method in which the at least one outlet opening of the load-dependent switchable cylinder of a charge exchange group is opened again when the cylinder-associated piston is on the way from bottom dead center (UT) to top dead center (TDC) are advantageous in this connection.

In this context, embodiments of the method are advantageous in which the at least one outlet opening of the load-dependent switchable cylinder of a charge exchange group is opened 30 to 80 ° CA after bottom dead center (UT), preferably 30 to 60 ° CA after bottom dead center (UT) or 40 to 50 ° CA after bottom dead center (UT).

In this context, embodiments of the method are advantageous in which the at least one outlet opening of the load-dependent switchable cylinder of a charge exchange group is opened again, wherein the associated outlet valve performs a reduced valve lift.

Embodiments of the method in which the at least one outlet opening of the load-dependent switchable cylinder of a charge change group is closed again before the at least one outlet opening of the cylinder in operation of this charge change group is opened are advantageous.

Embodiments of the method in which the at least one outlet opening of the load-dependent switchable cylinder of a charge exchange group is closed again when the cylinder-associated piston is on the way from bottom dead center (UT) to top dead center (TDC) are also advantageous.

• – jeder Zylinder einen Kolben umfasst, der im Betrieb der Brennkraftmaschine zwischen einem unteren Totpunkt (UT) und einem oberen Totpunkt (OT) oszilliert,
• – jeder Zylinder mindestens eine Auslassöffnung aufweist, an die sich eine Abgasleitung zum Abführen der Abgase via Abgasabführsystem anschließt,
• – jeder Zylinder mindestens eine Einlassöffnung aufweist, an die sich eine Ansaugleitung zum Zuführen von Ladeluft via Ansaugsystem anschließt,
• – mindestens zwei Zylinder in der Art konfiguriert sind, dass diese mindestens zwei Gruppen mit jeweils mindestens einem Zylinder bilden, wobei der mindestens eine Zylinder einer ersten Gruppe ein auch bei Teilabschaltung der Brennkraftmaschine in Betrieb befindlicher Zylinder ist und der mindestens eine Zylinder einer zweiten Gruppe als lastabhängig schaltbarer Zylinder ausgebildet ist, und
• – mindestens ein Ventile umfassender Ventiltrieb zum Steuern eines vier Takte umfassenden Ladungswechsels vorgesehen ist, wobei jedes Ventil entlang einer Längsachse zwischen einer Ventilschließstellung und einer Ventiloffenstellung unter Vollführung eines maximalen Ventilhubs bewegbar ist, und die dadurch gekennzeichnet ist, dass
• – jeweils ein in Betrieb befindlicher Zylinder der ersten Gruppe mit einem bei Teilabschaltung abgeschalteten Zylinder der zweiten Gruppe via Überströmkanal verbindbar ist, wobei in dem Überströmkanal mindestens ein Absperrelement vorgesehen ist.

The second sub-task on which the invention is based, namely to provide an internal combustion engine for carrying out a method of the type described above, is achieved by an internal combustion engine with at least two cylinders arranged in series, in which

• Each cylinder comprises a piston which, during operation of the internal combustion engine, oscillates between a bottom dead center (UT) and a top dead center (TDC),
• Each cylinder has at least one outlet opening adjoined by an exhaust pipe for discharging the exhaust gases via the exhaust gas removal system,
• Each cylinder has at least one inlet opening adjoined by an intake line for supplying charge air via the intake system,
• - At least two cylinders are configured in such a way that they form at least two groups each having at least one cylinder, wherein the at least one cylinder of a first group is also in partial deactivation of the internal combustion engine in operation cylinder and the at least one cylinder of a second group as load-dependent switchable cylinder is formed, and
• - Valve drive comprising at least one valve is provided for controlling a charge cycle comprising four cycles, wherein each valve is movable along a longitudinal axis between a valve closed position and a valve open position under full control of a maximum valve lift, and which is characterized in that
• - In each case an in-service cylinder of the first group is connected to a switched off during partial shutdown cylinder of the second group via overflow, wherein in the overflow at least one shut-off is provided.

The comments made in connection with the method according to the invention also apply to the internal combustion engine according to the invention.

• – jeder Zylinder mindestens zwei Auslassöffnungen zum Abführen der Abgase aus dem Zylinder aufweist,
• – jeweils ein in Betrieb befindlicher Zylinder und ein abschaltbarer Zylinder eine Ladungswechselgruppe bilden, wobei jede Ladungswechselgruppe einen außenliegenden Zylinder und den benachbarten innenliegenden Zylinder umfasst,
• – die Auslassöffnungen der zwei Zylinder einer Ladungswechselgruppe sich gegenüberliegen, wobei die Abgasleitungen der Zylinder einer Ladungswechselgruppe unter Ausbildung eines im Zylinderkopf integrierten Abgaskrümmers zu einer gemeinsamen Abgasleitung zusammenführen, so dass das Abgasabführsystem der zwei Zylinder einer Ladungswechselgruppe als Überströmkanal dient.

Embodiments of an internal combustion engine with four cylinders arranged in series along a longitudinal axis of a cylinder head, which are characterized in that they are advantageous, are advantageous

• Each cylinder has at least two outlet openings for discharging the exhaust gases out of the cylinder,
• In each case an in-service cylinder and a deactivatable cylinder form a charge-change group, each charge-change group comprising an outer cylinder and the adjacent inner cylinder,
• The outlet openings of the two cylinders of a charge exchange group are opposite one another, wherein the exhaust gas lines of the cylinders of a charge exchange group combine to form a common exhaust pipe in the cylinder head, so that the exhaust gas removal system of the two cylinders of a charge exchange group serves as an overflow channel.

As part of the charge cycle, the combustion gases are pushed out via the outlet openings of the cylinders and the cylinders are filled with fresh mixture or air via the inlet openings. It is the task of the valve drive to open the inlet and outlet openings in time or to close, with a quick release of the largest possible flow cross-sections is sought to keep the throttle losses low and the best possible filling or an effective, d. H. To ensure complete removal of the exhaust gases. Therefore, it is also advantageous to equip each cylinder with two or more outlet openings. The required for the movement of the valves valve actuating mechanism including the valves themselves is referred to as a valve train.

The merging of the exhaust pipes of a charge exchange group within the cylinder head allows a compact design of the internal combustion engine, a dense packaging of the drive unit and a reduction of the components.

The integration of the exhaust manifold of a charge cycle group in the cylinder head also has the advantage that can be participated in an optionally provided in the cylinder head liquid cooling, in the way that the manifold does not have to be made of thermally highly resilient and therefore costly materials.

It should also be borne in mind that, in the case of an exhaust gas turbocharger, the turbine of the exhaust gas turbocharger should be arranged as close as possible to the outlet of the cylinders in order to be able to optimally utilize the exhaust gas enthalpy of the hot exhaust gases, which is largely determined by the exhaust gas pressure and the exhaust gas temperature, and to ensure a fast response of the turbine or the turbocharger. Furthermore, the path of the hot exhaust gases to the various exhaust aftertreatment systems should be as short as possible, so that the exhaust gases are given little time to cool and the exhaust aftertreatment systems reach their operating temperature or light-off as soon as possible, especially after a cold start of the engine.

It is therefore endeavored in exhaust-gas-fired internal combustion engines to minimize the thermal inertia of the section of Abgasabführsystems between exhaust port on the cylinder and turbine or between the exhaust port on the cylinder and exhaust aftertreatment system, which Reduction of the mass and the length of this section can be achieved., For example, by integration of the exhaust manifold in the cylinder head.

As has already been explained, it is advantageous to design the overflow channel of a charge exchange group as small as possible or as short as possible. Also in this regard, the integration of the exhaust manifold of a charge cycle group in the cylinder head is expedient if, as in the present case, the Abgasabführsystem the two cylinders of a charge cycle group is used as overflow.

Embodiments of the internal combustion engine in which the at least two outlet openings of each cylinder are each arranged along a virtual straight line which forms an angle α with the longitudinal axis of the cylinder head are advantageous, with 70 ° ≦ α ≦ 110 °.

This embodiment specifies the opposing of the outlet openings of the two cylinders of a charge exchange group. It should be noted that the opposite of the outlet openings in particular serves a small-volume and as short as possible embodiment of the overflow.

• – eine virtuelle Gerade, welche eine Auslassöffnung des in Betrieb befindlichen Zylinders einer Ladungswechselgruppe mit einer Auslassöffnung des abschaltbaren Zylinders dieser Ladungswechselgruppe verbindet, durch den integrierten Abgaskrümmer dieser Ladungswechselgruppe hindurch verläuft.

Also advantageous are embodiments of the internal combustion engine, in which

• A virtual straight line which connects an outlet opening of the cylinder in operation of a charge exchange group to an outlet opening of the deactivatable cylinder of this charge exchange group, extends through the integrated exhaust manifold of this charge exchange group.

If the Abgasabführsystem or the exhaust manifold of a charge exchange group is carried out as described above, a direct, d. H. straight forward passing of exhaust gas. This reduces the distance, the time for the transfer and the pressure loss to be accepted.

Embodiments of the internal combustion engine in which the at least one shut-off element is an outlet valve of a cylinder are advantageous. If an exhaust valve of a cylinder is used as a shut-off, eliminating the need to provide an additional element and an actuator for this purpose.

In the following the invention is based on an embodiment according to the 1 . 2a and 2 B described in more detail. Hereby shows:

1 schematically the cylinder head of a first embodiment of teilabschaltbaren internal combustion engine in section,

2a the Ventilerhebungskurven an exhaust gas-producing in operation first cylinder and an exhaust gas-receiving turn-off second cylinder in normal operation, and

2 B the valve lift curves of an exhaust gas-producing in operation first cylinder and an exhaust gas-receiving switched-off second cylinder at partial shutdown.

1 schematically shows the four cylinders 1 . 2 . 3 . 4 a spark-ignited four-cylinder in-line engine 7 in a section through the cylinder head 8th , The four cylinders 1 . 2 . 3 . 4 are in series, ie along the longitudinal axis 8a of the cylinder head 8th arranged.

Every cylinder 1 . 2 . 3 . 4 has two outlet openings 1a . 2a . 3a . 4a and two inlet openings 1b . 2 B . 3b . 4b on, being attached to each outlet opening 1a . 2a . 3a . 4a an exhaust pipe for discharging the exhaust gases and to each intake port 1b . 2 B . 3b . 4b a suction line for supplying air connects.

The four cylinders 1 . 2 . 3 . 4 are also configured to form two groups of two cylinders each 1 . 2 . 3 . 4 , where the two outer cylinders 1 . 4 form a first group whose cylinder 1 . 4 even with partial shutdown of the internal combustion engine 7 are in operation, and the two inner cylinders 2 . 3 form a second group whose cylinder 2 . 3 as a load-dependent switchable cylinder 2 . 3 are formed, which are turned off in the context of a partial shutdown.

The internal switchable cylinders 2 . 3 be switched off in partial load operation falls below a predetermined load and that by deactivating the fuel injection and spark ignition (not shown). This increases the load requirement on the outer cylinders which are still in operation 1 . 4 which then operate at higher load with lower specific fuel consumption. An improvement in the efficiency is the result.

In order to reduce the charge cycle losses during partial shutdown, exhaust gas from the operating cylinders 1 . 4 during the charge change in the deactivated cylinders 2 . 3 reconciled. The transfer process can be in a deactivated cylinder 2 . 3 provide an overpressure or pressure increase, which also in the deactivated cylinder 2 . 3 a torque is generated. Because of hot exhaust gas in the deactivated cylinders 2 . 3 passed, these cylinders cool 2 . 3 at Teilabschaltung not off, which has advantages.

In each case a cylinder in operation 1 . 4 and a deactivated cylinder 2 . 3 are grouped into a charge change group, wherein in each case two adjacent cylinders 1 . 2 . 3 . 4 ie an outboard cylinder 1 . 4 and the adjacent inner cylinder 2 . 3 form a charge change group. During partial shutdown, exhaust gas will be out of the operating outer cylinder 1 . 4 in the deactivated adjacent cylinder 2 . 3 initiated. These are the cylinders 1 . 2 . 3 . 4 a charge change group each via overflow 5a . 5b connectable, wherein at least one outlet valve serves as a shut-off and the overflow 5a . 5b blocked or released.

The outlet openings 1a . 2a . 3a . 4a the cylinder 1 . 2 . 3 . 4 a charge change group are facing each other, with the outlet openings 1a . 2a . 3a . 4a every cylinder 1 . 2 . 3 . 4 are arranged on a virtual line, with the longitudinal axis 8a of the cylinder head 8th forms almost a right angle α.

The exhaust pipes of the cylinders 1 . 2 . 3 . 4 a charge change group lead to the formation of a cylinder head 8th integrated exhaust manifold 6a . 6b to a common exhaust pipe together, wherein in each case the Abgasabführsystem or the manifold 6a . 6b the two cylinders 1 . 2 . 3 . 4 a charge change group as overflow channel 5a . 5b serves.

So that the two exhaust-receiving deactivated cylinder 2 . 3 cylinders preceding in the firing order 2 . 3 and the two exhaust-producing cylinders in operation 1 . 4 in the firing order following cylinders 1 . 4 , the cylinders become 1 . 2 . 3 . 4 of the four-cylinder in-line engine 7 operated with the ignition sequence 1-3-4-2. Then the fourth cylinder delivers 4 Exhaust gas for the preceding in the firing order third cylinder 3 and the first cylinder 1 Exhaust for the preceding in the firing order second cylinder 2 ,

2a shows the valve lift curves A ₁ , A ₂ , E ₁ , E _{2 of} an exhaust gas-producing in operation first cylinder 1 and an exhaust-receiving turn-off second cylinder 2 in normal operation.

2 B shows the valve lift curves A ₁ , A ₂ , E _{1 of} an exhaust gas supplying operating in the first cylinder 1 and an exhaust-receiving deactivated second cylinder 2 at partial shutdown.

At the in 2 B shown method variant, the inlet openings and the outlet openings of the first cylinder in operation 1 operated at partial shutdown during the charge change with unchanged control times. The valve lift curves A ₁ and E _{1 of} the first cylinder 1 remain unchanged.

The inlet openings of the deactivated second cylinder 2 are kept closed during partial shutdown, which is why the valve lift curve E _{1 is} omitted. On the other hand, the outlet openings of the deactivated second cylinder 2 operated at partial shutdown with changed control times.

The outlet ports of the deactivated second cylinder 2 are opened in the present case, shortly after the outlet openings of the first cylinder in operation 1 were opened. The offset ensures that the piston of the exhaust-receiving second cylinder 2 does not collide near the top dead center (TDC ₂ ) with the associated exhaust valves. The first cylinder 1 supplies exhaust gas for the second cylinder as part of a Ausschiebetaktes 2 , The transfer of exhaust gas is supported by an upward stroke of the piston of the first cylinder 1 and a downward stroke of the piston of the second cylinder 2 in the context of an intake stroke.

Closed are the outlet openings of the deactivated second cylinder 2 when the cylinder-associated piston is on the way from bottom dead center (UT ₂ ) to top dead center (TDC ₂ ). About the closing time of the outlet openings in the second cylinder 2 set remaining exhaust gas amount, which is such that no too large negative pressure in the deactivated cylinder 2 until the next opening. In the present case, the outlet openings of the second cylinder 2 closed about 35 ° CA before top dead center (TDC ₂ ), the associated exhaust valves are kept open while maintaining a reduced valve lift for a predetermined crank angle range when the cylinder-associated piston on the way from bottom dead center (UT ₂ ) to top dead center ( OT ₂ ) is located.

The outlet ports of the deactivated second cylinder 2 are opened again when the cylinder-associated piston is again on the way from bottom dead center (UT ₂ ) to top dead center (TDC ₂ ) and before the outlet openings of the exhaust gas supplying the first cylinder 1 be opened again. The associated exhaust valve performs a reduced valve lift. The in the exhaust gas-receiving cylinder 2 übergeleitete exhaust gas amount is ejected and discharged via Abgasabführsystem to initiate hot exhaust gas in the subsequent cycle again.

LIST OF REFERENCE NUMBERS

1

 first cylinder, outboard cylinder

1a

 Outlet opening of the first cylinder

1b

 Inlet opening of the first cylinder

2

 second cylinder, internal cylinder, switchable cylinder

2a

 Outlet opening of the second cylinder

2 B

 Inlet opening of the second cylinder

3

 third cylinder, internal cylinder, switchable cylinder

3a

 Outlet opening of the third cylinder

3b

 Inlet opening of the third cylinder

4

 fourth cylinder, outboard cylinder

4a

 Outlet opening of the fourth cylinder

4b

 Inlet opening of the fourth cylinder

5a

 Overflow channel of the first charge exchange group

5b

 Overflow channel of the second charge change group

6a

 integrated exhaust manifold of the first charge change group

6b

 integrated exhaust manifold of the second charge change group

7

 Internal combustion engine, four-cylinder in-line engine

8th

 cylinder head

8a

 Longitudinal axis of the cylinder head

° CA

 Degree crank angle

A ₁

 Valve lift curve from the outlet of the first cylinder

A ₂

 Valve lift curve from the outlet of the second cylinder

E ₁

 Valve lift curve from the inlet of the first cylinder

E ₂

 Valve lift curve from the inlet of the second cylinder

UT

 bottom dead center

OT

 Top Dead Center

UT ₁

 bottom dead center of the first cylinder

OT ₁

 top dead center of the first cylinder

UT ₂

 bottom dead center of the second cylinder

OT ₂

 top dead center of the second cylinder

Claims (23)

Method for operating a partially switched off internal combustion engine ( 7 ) with at least two cylinders arranged in series ( 1 . 2 . 3 . 4 ), in which - each cylinder ( 1 . 2 . 3 . 4 ) comprises a piston which in the operation of the internal combustion engine ( 7 ) oscillates between a bottom dead center (UT) and a top dead center (TDC), 1 . 2 . 3 . 4 ) at least one outlet opening ( 1a . 2a . 3a . 4a ), to which an exhaust pipe for discharging the exhaust gases via Abgasabführsystem connects, - each cylinder ( 1 . 2 . 3 . 4 ) at least one inlet opening ( 1b . 2 B . 3b . 4b ), which is followed by an intake line for supplying charge air via the intake system, - at least two cylinders ( 1 . 2 . 3 . 4 ) are configured in such a way that these at least two groups each having at least one cylinder ( 1 . 2 . 3 . 4 ), wherein the at least one cylinder ( 1 . 4 ) a first group also at partial shutdown of the internal combustion engine ( 7 ) operating cylinder ( 1 . 4 ) and the at least one cylinder ( 2 . 3 ) of a second group as a load-dependent switchable cylinder ( 2 . 3 ), and - at least one valves comprehensive valve drive for controlling a four-cycle charge change is provided, each valve along a longitudinal axis between a valve closed position and a valve open position under full control of a maximum valve lift is movable, characterized in that - one exhaust gas in operation located cylinder ( 1 . 4 ) of the first group during the charge exchange from this exhaust gas supplying cylinder ( 1 . 4 ) is discharged and via the overflow channel ( 5a . 5b ) in a deactivated cylinder ( 2 . 3 ) of the second group during the charge cycle of this exhaust gas-receiving cylinder ( 2 . 3 ), wherein as the exhaust-gas-receiving deactivated cylinder ( 2 . 3 ) of the second group is a cylinder preceding in the firing order ( 2 . 3 ) is used and as exhaust gas in operating cylinder ( 1 . 4 ) of the first group is a cylinder following in the firing order ( 1 . 4 ) is used and in the overflow channel ( 5a . 5b ) At least one shut-off is provided. A method according to claim 1, characterized in that in each case a cylinder in operation ( 1 . 4 ) and a deactivated cylinder ( 2 . 3 ) are combined into a charge cycle group, wherein exhaust gas from the operating cylinder ( 1 . 4 ) in the deactivated cylinder ( 2 . 3 ) is initiated. Method according to claim 2, characterized in that in each case two adjacent cylinders ( 1 . 2 . 3 . 4 ) are combined into a charge change group. Method according to Claim 3 for operating a partially switched-off internal combustion engine ( 7 ), in which the exhaust pipes of the two cylinders ( 1 . 2 . 3 . 4 ) a charge exchange group with formation of an exhaust manifold ( 6a . 6b ) merge into a common exhaust pipe, characterized in that the Abgasabführsystem the two cylinders ( 1 . 2 . 3 . 4 ) as overflow channel ( 5a . 5b ) is used. Method according to one of the preceding claims, characterized in that the at least one outlet opening ( 1a . 4a ) of the at least one operating cylinder ( 1 . 4 ) at Partial shutdown is operated during the charge change with unchanged control times. Method according to one of the preceding claims, characterized in that the at least one inlet opening ( 2 B . 3b ) of the at least one load-dependent switchable cylinder ( 2 . 3 ) is kept closed during partial shutdown. Method according to one of the preceding claims, characterized in that at least one outlet opening ( 2a . 3a ) each load-dependent switchable cylinder ( 2 . 3 ) is operated at partial shutdown with changed control times. A method according to claim 7, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) of a charge change group is opened when the at least one outlet opening ( 1a . 4a ) of the cylinder in operation ( 1 . 4 ) of this charge change group is opened. A method according to claim 7, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) of a charge change group is opened later than the at least one discharge opening ( 1a . 4a ) of the cylinder in operation ( 1 . 4 ) of this charge change group. Method according to one of claims 7 to 9, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) of a charge change group is closed when the cylinder-associated piston is on the way from bottom dead center (UT) to top dead center (TDC). A method according to claim 10, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) a charge change group 30 to 60 ° CA before top dead center (TDC) is closed. A method according to claim 10 or 11, characterized in that to the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) is maintained open while maintaining a reduced valve lift for a predetermined crank angle range when the cylinder-associated piston is on the way from bottom dead center (UT) to top dead center (TDC). Method according to one of claims 7 to 12, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) a charge exchange group is opened again before the at least one outlet opening ( 1a . 4a ) of the cylinder in operation ( 1 . 4 ) of this charge change group is opened. A method according to claim 13, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) of a charge change group is opened again when the cylinder-associated piston is on the way from bottom dead center (UT) to top dead center (TDC). A method according to claim 14, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) of a charge change group 30 to 60 ° CA after the bottom dead center (UT) is opened. Method according to one of claims 13 to 15, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) is opened again a charge change group, wherein the associated exhaust valve performs a reduced valve lift. Method according to one of claims 13 to 16, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) is closed again before the at least one outlet opening ( 1a . 4a ) of the cylinder in operation ( 1 . 4 ) of this charge change group is opened. Method according to one of claims 13 to 17, characterized in that the at least one outlet opening ( 2a . 3a ) of the load-dependent switchable cylinder ( 2 . 3 ) is closed again when the cylinder-associated piston is on the way from bottom dead center (UT) to top dead center (TDC). Internal combustion engine ( 7 ) for carrying out a method according to one of the preceding claims with at least two cylinders arranged in series ( 1 . 2 . 3 . 4 ), in which - each cylinder ( 1 . 2 . 3 . 4 ) comprises a piston which in the operation of the internal combustion engine ( 7 ) oscillates between a bottom dead center (UT) and a top dead center (TDC), 1 . 2 . 3 . 4 ) at least one outlet opening ( 1a . 2a . 3a . 4a ), to which an exhaust pipe for discharging the exhaust gases via Abgasabführsystem connects, - each cylinder ( 1 . 2 . 3 . 4 ) at least one inlet opening ( 1b . 2 B . 3b . 4b ), which is followed by an intake line for supplying charge air via the intake system, - at least two cylinders ( 1 . 2 . 3 . 4 ) are configured in such a way that they have at least two groups each at least one cylinder ( 1 . 2 . 3 . 4 ), wherein the at least one cylinder ( 1 . 4 ) a first group also at partial shutdown of the internal combustion engine ( 7 ) operating cylinder ( 1 . 4 ) and the at least one cylinder ( 2 . 3 ) of a second group as a load-dependent switchable cylinder ( 2 . 3 ), and - at least one valve comprehensive valve drive for controlling a four-stroke charge change is provided, each valve is movable along a longitudinal axis between a valve closed position and a valve open position under full control of a maximum valve lift, characterized in that - each one in operation located cylinder ( 1 . 4 ) of the first group with a shutdown during partial shutdown ( 2 . 3 ) of the second group via overflow channel ( 5a . 5b ) is connectable, wherein in this overflow ( 5a . 5b ) At least one shut-off is provided. Internal combustion engine ( 7 ) according to claim 19 with four along a longitudinal axis ( 8a ) of a cylinder head ( 8th ) arranged in series cylinders ( 1 . 2 . 3 . 4 ), characterized in that - each cylinder ( 1 . 2 . 3 . 4 ) at least two outlet openings ( 1a . 2a . 3a . 4a ) for discharging the exhaust gases from the cylinder ( 1 . 2 . 3 . 4 ), - in each case an operating cylinder ( 1 . 4 ) and a deactivatable cylinder ( 2 . 3 ) form a gas exchange group, each gas exchange group comprising an external cylinder ( 1 . 4 ) and the adjacent inner cylinder ( 2 . 3 ), - the outlet openings ( 1a . 2a . 3a . 4a ) of the two cylinders ( 1 . 2 . 3 . 4 ) are opposite to a charge exchange group, wherein the exhaust gas lines of the cylinder ( 1 . 2 . 3 . 4 ) a charge change group to form a cylinder head ( 8th ) integrated exhaust manifold ( 6a . 6b ) merge to a common exhaust pipe, so that the Abgasabführsystem the two cylinders ( 1 . 2 . 3 . 4 ) of a charge change group as overflow channel ( 5a . 5b ) serves. Internal combustion engine ( 7 ) according to claim 20, characterized in that - the at least two outlet openings ( 1a . 2a . 3a . 4a ) of each cylinder ( 1 . 2 . 3 . 4 ) are respectively arranged along a virtual straight line, which with the longitudinal axis ( 8a ) of the cylinder head ( 8th ) forms an angle α, with 70 ° ≤ α ≤ 110 °. Internal combustion engine ( 7 ) according to claim 20 or 21, characterized in that - a virtual straight line which has an outlet opening ( 1a . 4a ) of the cylinder in operation ( 1 . 4 ) a charge exchange group with an outlet opening ( 2a . 3a ) of the deactivatable cylinder ( 2 . 3 ) connects this charge change group, passes through the integrated exhaust manifold of this charge cycle group. Internal combustion engine ( 7 ) according to one of claims 19 to 22, characterized in that the at least one shut-off element is an outlet valve of a cylinder ( 1 . 2 . 3 . 4 ).

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