WO2011107127A1

WO2011107127A1 - Method for operating a reciprocating piston machine

Info

Publication number: WO2011107127A1
Application number: PCT/EP2010/007313
Authority: WO
Inventors: Tilmann RÖMHELD; Michael Wagenplast
Original assignee: Daimler Ag
Priority date: 2010-03-02
Filing date: 2010-12-02
Publication date: 2011-09-09
Also published as: DE102010009910A1

Abstract

The invention relates to a method for operating a reciprocating piston machine, in which method at least one lever element (16) which is mounted on a crank pin (14) of a crank shaft (12) and is connected to a corresponding connecting rod (18) is set by means of a corresponding adjustment device (24) for setting the compression ratio of the reciprocating piston machine between at least two rotary positions relative to the crank pin (14), wherein at least two lever elements (16) which are mounted on a respective crank pin (14) and are each connected to a corresponding connecting rod (18) are set independently of one another, by means of one assigned adjustment device (24) each, to different respective rotary positions relative to the respectively corresponding crank pin (14), in order to set the compression ratio.

Description

Method for operating a reciprocating piston engine

The invention relates to a method for operating a reciprocating engine specified in the preamble of claim 1. Art.

WO 2007/092168 A2 discloses an internal combustion engine with an adjustable compression ratio. To set the compression ratio is a

Crankshaft of the internal combustion engine mounted on an eccentric carrier, whereby the position of the axis of rotation of the crankshaft in a crankcase of the

Internal combustion engine can be adjusted. The eccentric carrier is actuated via a fork of a hydraulic actuator. This internal combustion engine has further potential for representing efficient operation.

From WO 02/12694 A1 a reciprocating internal combustion engine with a displaceably arranged in a cylinder piston is known, which is pivotally coupled to a connecting rod and whose movement is transferable to a crank of a crankshaft of the reciprocating internal combustion engine. Between the connecting rod and the crank is a

Transmitter provided whose movement is manipulated by a control lever, with the aim of ensuring a controllable movement of the piston, in particular to allow a variation of the compression ratio. These too

Reciprocating internal combustion engine has potential for representing even more efficient operation.

US 2007/0150164 1 discloses an internal combustion engine with a variable

Compression ratio and a method for operating such

An internal combustion engine, which is adapted to be operated with one of a plurality of compression ratios selectable compression ratio. Also, this internal combustion engine has further potential to make its operation more efficient. It is therefore an object of the present invention to provide a method for operating a reciprocating engine, which enables efficient operation.

This object is achieved by a method for operating a reciprocating engine having the features of patent claim 1. Advantageous embodiments with

expedient and non-trivial developments of the invention are specified in the dependent claims.

An inventive method for operating a reciprocating engine, in which at least one mounted on a crank pin of a crankshaft and connected to a corresponding connecting rod lever element is adjusted by means of a corresponding adjusting device for adjusting the compression ratio of the reciprocating engine between at least two rotational positions relative to the crank pin is characterized in that at least two lever elements mounted on a respective crank pin and connected to a corresponding connecting rod are each independently connected to each other by means of an associated actuating device

Setting the compression ratio in each, different rotational positions are adjusted relative to the respective corresponding crank pin. This means that respective compression ratios of respective, corresponding to the respective crank pin, of respective, to the respective crank pin

corresponding work spaces, in particular cylinders, the reciprocating engine are set, which differ from each other.

This workspace individual adjustment of the compression ratio

or the compression ratios allows the representation of a very efficient operation of the reciprocating engine, since the compression ratio can be adapted to respective prevailing conditions in the working space. If, for example, one of these working spaces is operated in a fired mode in which fuel is introduced into the working space, in particular injected, and a mixture of fuel and air is burned, while the other of the work spaces is operated in a non-fired operation, in which no fuel in the

Working space is introduced, as is the case for example in a pushing operation, these mutually different operating conditions of the work spaces possibly different from each other, respective compression ratios and thus different settings of the respective lever elements relative to the respective corresponding crank pin for representing optimal conditions in the working space. This leads to a very efficient operation of the reciprocating engine. This is possible by the method according to the invention, resulting in a lower

Fuel consumption and thus low C0 ₂ emissions of the reciprocating engine result.

In a coasting operation of the reciprocating engine, in which the reciprocating engine is thus driven via wheels of a motor vehicle, it is advantageous for saving fuel, a fuel supply to the working spaces, in particular cylinder, the

To finish reciprocating engine or to introduce no fuel into the work spaces, as combustion processes for the operation of the reciprocating engine are not required. At the same time, however, it is desirable to keep an exhaust aftertreatment device, for example a catalyst, corresponding to the reciprocating piston engine at operating temperature, in order to ensure a delay-free cleaning of exhaust gas of the reciprocating piston engine in a fired operation of the reciprocating engine which follows the overrun operation in time

To ensure exhaust aftertreatment device. To the

Exhaust aftertreatment device to maintain operating temperature is introduced into at least one of the working spaces in the overrun fuel, either to generate hot exhaust gas either as a result of combustion, with this exhaust the

Keep the exhaust aftertreatment device at its operating temperature or to push out unburned fuel from the working space, whereupon the unburned fuel ignites at the still warm exhaust aftertreatment device and this keeps warm as a result of this combustion or heated.

If a working space is now operated in a non-fired operation, while a further working space is described in a fired state, then, as already explained, these different operating states may be required

different compression ratios in order to represent optimal conditions for representing an efficient operation of the reciprocating engine. The

inventive method now allows this setting the

Working space individual conditions by the individual working space adjustment of the lever elements and thus the compression ratios.

In an advantageous embodiment of the invention, in a coasting operation and / or in an idling operation of the reciprocating engine by adjusting at least one lever element corresponding to the one lever element

Compression ratio or the compression ratio of the one Lever element corresponding working space, in particular cylinder, and reduced by adjusting at least one further lever member corresponding to the at least one further lever element compression ratio or the compression ratio of the at least one further lever element

corresponding working space, in particular cylinder, increased. As a result, optimal boundary conditions are created in the respective work spaces to take into account the respective operating conditions of the work spaces and to set a very efficient operation of the reciprocating engine.

A particularly efficient and therefore fuel - efficient operation of the

Reciprocating engine while keeping the exhaust gas purification device to operating temperature is thereby realized that fuel in the working space

introduced, in particular injected, which to the lever element

By adjusting the corresponding compression ratio is increased, for example, while the fuel supply is terminated in the working space, which corresponds to the lever element, by adjusting the

corresponding compression ratio is reduced.

It should be noted at this point that the introduction of fuel into the respective working space is accompanied by a fired operation of the respective working space, whereby combustion takes place in the working space. In this case, the

Adjustment of the compression ratio and thus the representation of optimal

Combustion conditions particularly advantageous. Furthermore, the termination of the fuel supply in the respective working space is accompanied by a non-fired operation of the internal combustion engine.

In a particularly advantageous embodiment of the invention, first of all, fuel is introduced into the at least one working space of the reciprocating piston engine corresponding to the one of the lever elements, and the fuel supply in the at least one further corresponds to the one further lever element

Working space of the reciprocating engine finished. After a predetermined period of time, in particular in a coasting operation and / or in an idling operation of

Reciprocating engine, the fuel supply is terminated in the at least one corresponding to the one of the lever elements working space of the reciprocating engine and introduced fuel into the at least one further to the one further of the lever elements corresponding working space. This means that after this period of time fuel is introduced into the working space, during which during the Time duration, so over this time, the fuel supply has not taken place, so ended or was suspended and at the same time after this period of time, the fuel supply to the working space is terminated, in which during this period, that is, over this time, fuel was introduced. This allows for a reduction of fuel consumption while keeping the

Exhaust after-treatment device on the operating temperature and at the same time avoid excessive cooling of the working space, the fuel supply is terminated first. This has a positive effect on the conditions for subsequent combustion and lubricating properties of lubricant, in particular

Lubricating oil, the reciprocating engine off.

If the reciprocating engine is designed, for example, as a four-cylinder reciprocating engine, that is to say if the crankshaft has four crankpins, then it is extreme

advantageous, for example, if two cylinders with a high

Compression ratio and two cylinders with a relatively low

Be operated compression ratio, wherein only introduced into two of these cylinders fuel and combustion is carried out, so they are operated in a fired operation. Advantageously, the introduction of fuel or the termination of the fuel supply takes place as a function of a firing order of the cylinders. It is also possible that in a cylinder by adjusting the

corresponding high compression ratio and the other three cylinders a relatively low compression ratio is set. A reverse adjustment is also possible, so with three cylinders, a high compression ratio is set, while in a cylinder, a relatively low compression ratio is set. The same applies to the introduction and thus for the fired or non-fired operation of the cylinder, that is introduced into a cylinder fuel and this is fired, while the fuel supply to the other three cylinders is terminated and they are operated in a non-fired operation or vice versa. As already stated, it is advantageous for the combustion, the compression ratio of the

Cylinder or to increase the compression ratios of the cylinder, which are operated fired, ie, in which fuel is introduced while the compression ratio of the cylinder or the compression ratios of the cylinders that are not fired, ie in which no fuel is introduced, especially in comparison to the high compression ratio or to the high compression ratios to reduce. The same applies to a three-cylinder internal combustion engine, which thus has three cylinders and thus a crankshaft with three crank pins. In this case, for example, the compression ratios of two cylinders are increased and the

Compression ratio of the third cylinder in particular reduced relative thereto. A reverse adjustment is also possible. Further, it is also possible to introduce and operate fuel in two of the cylinders while stopping fuel supply to the third cylinder and terminating it in a non-fired operation.

From the comments it is apparent that the reciprocating piston engine according to the invention offers a very high flexibility and many degrees of freedom to significantly reduce fuel consumption and thus the C0 ₂ emissions while maintaining low

Emissions and exhaust emissions as a result of holding the

Exhaust gas aftertreatment device to its operating temperature.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features mentioned above in the description and

Combinations of features as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively indicated combination but also in other combinations or alone, without departing from the scope of the invention.

The drawings show in:

1 is a perspective and partially sectioned view of a crank mechanism of a reciprocating engine with a crankshaft with four crank pins, on each of which a connected to a corresponding connecting rod lever member is mounted, each of the lever elements is assigned a hydraulically actuated and a translational movement executable actuator, by means of which the respective lever element for adjusting the compression ratio of the reciprocating engine is set between at least two rotational positions relative to the respective crank pin; Fig. 2 is a perspective and partially sectioned view of a with a

Connecting rod and an associated actuating device connected lever element of FIG. 1;

Fig. 3 is another perspective view of the conrod and the

Actuator connected lever element of FIG. 2;

Fig. 4 is a partially sectioned plan view of the conrod and the

Actuator connected lever element according to Figures 2 and 3.

Fig. 5 is a sectional view of an adjusting device according to the preceding

Characters; and

6 shows five longitudinal sectional views of the adjusting device according to FIG. 5 in FIG

different positions for presentation

different rotational positions of the lever element and thus to represent different compression ratios of the reciprocating engine.

1 shows a crank mechanism 10 of a reciprocating engine with a crankshaft 12. The crankshaft 12 has four crank pins 14, on each of which a lever element 16 is mounted, so that the lever elements 16 can rotate relative to the respective crank pins 14. The lever elements 16 are each pivotally connected to a connecting rod 18 and formed as a transverse lever which transverse to the axis of rotation of the

Crankshaft 12 run. The connecting rods 18 in turn each have a connecting rod 22, via which the respective connecting rod 22 with a piston of the reciprocating piston displaceably arranged in a cylinder of the reciprocating engine is connectable. As is known, the pistons of the reciprocating engine due to gas expansions by combustion of a fuel-air mixture in the respective cylinder through translational movements, which transmitted via the connecting rods 18 and the lever members 16 on the crank pin 14 and on to the crankshaft 12 and in a rotational movement of the crankshaft 12 are converted, so that the crankshaft 12 according to a direction arrow 20 rotates about its axis of rotation.

As can be seen from FIG. 1, the pistons and thus the connecting rods 22 always apply the same stroke, ie the same translatory upward and downward movement. To illustrate an adjustable compression ratio of the reciprocating engine is associated with each lever element 16 is an adjusting device 24, which is connected in an articulated manner to the respective lever element 16. By means of the adjusting devices 24, the lever elements 16 between at least two rotational positions relative to the respective crank pin 14 rotatable about this. This causes an adjustment of a final volume, which is also referred to as compression volume, in the respective cylinder at top dead center of the respective piston, since the rotational position of the lever elements 16 relative to the respective crank pin 14 affects the translational position of the bottom and top dead center of the piston in the cylinder , An enlargement of the

Compression volume leads to a reduction of the compression ratio and / or vice versa. To adjust the lever member 16 and thus the

Compression ratio of the reciprocating engine, the adjusting devices 24 perform a translational movement, which causes a rotation of the respective lever member 16 relative to the respective crank pin 14 about this.

For the sake of clarity, the function of the actuators 24 is based on a

Setting device 24 explained, which is shown in the following figures. FIGS. 2 to 5 show the adjusting device 24, which has a working space 26

Hydraulic cylinder 28 includes. In the hydraulic cylinder 28 and its working space 26, a displaceable piston 30 is arranged, which is fixedly connected to a push rod 32. The piston 30 divides the working space 28 into a first, in the Fig. 2 upper control chamber 34 and a lower, in Fig. 2, the second control chamber 36, wherein the control chambers 34 and 36 have a respective volume, which with a working medium in the form of Lubricating oil of the reciprocating engine can be acted upon. In Fig. 2, the piston 30 and thus the push rod 32 is in a first end position in which the volume of the control chamber 34 is minimal and the volume of the control chamber 36 is maximum. In this case, the volume of the control chamber 36 is filled with the lubricating oil while the control chamber 34 contains at least almost no lubricating oil.

2, the lever element 16 assumes a first rotational position relative to the crank pin 14, in which a low compression ratio of, for example, ε = 7 is present. If the compression ratio is increased, the piston 30 and thus the

Adjusting device 24 moved out of the first end position shown in FIG. 2 and the piston 30 are moved in the direction of a surface 38. This means that the volume of the control chamber 36 is reduced and the volume of the control chamber 34 must be increased. For this purpose, the lubricating oil has to be removed from the control chamber 36 and lubricating oil introduced into the control chamber 34.

In order to allocate appropriate and desired amounts of lubricating oil to the respective control chamber 34 and 36, channels 40, 42, 44 and 46 are provided through which the lubricating oil can flow. The channels 40, 42 and 44 are releasable and closable by corresponding control edges 48, 50 and 52 of a partially received in the push rod 32 control piston 54.

To increase the compression ratio now give the corresponding

Control edges 48, 50 and 52, the channels 40 and 42 free, whereupon the lubricating oil can flow into the control chamber 34 via the channel 40 from the control chamber 36 and via the channel 42. In addition, further lubricating oil can flow via the channel 46 into the control chamber 34, which lubricating oil can be supplied via a shaft 62. The channel 46 is connected to a lubricating oil supply of the reciprocating engine and ensures the supply of the adjusting device 24 with sufficient working fluid in the form of

Lubricating oil. Corresponding control valves in the form of check valves 56, 58 and 60 prevent an undesirable flow of lubricating oil.

The adjusting device 24 can in particular by using the check valves 56, 58 and 60 additional means for pressure enhancement of the lubricant, ie

Pumps, obsolete or allows at least a small dimensioning of such a device in terms of dimensions and performance, since the actuating device 24 virtually independently as a result of voltage applied to the push rod 32 alternating forces the lubricating oil in and out of the control chambers 34 and 36 promotes and that according to the Channels 40, 42 and 44 released or closed by the control edges 48, 50 and 52. The aforementioned alternating forces result from pressure and gas forces in the cylinder resulting from the abovementioned combustion, which occur via the piston, the connecting rod 18 and the lever element 16 the push rod 32 and thus transferred to the piston 30, thus the lubricating oil in or out of the corresponding

Control chambers 34 and / or 36 pumps.

This means an extremely low energy requirement for setting the

Compression ratio, which keeps the fuel consumption and thus the C0 ₂ emissions of the reciprocating engine in a small frame. The fact that the adjusting device 24 performs a translational movement, it has the further advantage that it has only a small space requirement while achieving a very precise adjustment of the compression ratio, whereby the reciprocating engine can be adapted very precisely to different operating points and thus a very efficient Operation possible.

As becomes clear in conjunction with FIG. 1, the crank mechanism 10 and thus the reciprocating engine further have the advantage that the lever elements 16 can be adjusted independently of one another by the adjusting devices 24, as a result of which

Compression ratio of each cylinder is selectively adjustable.

Thus, the adjusting device 24 perform movements of the lever member 16 and movements of the reciprocating engine with and possibly compensate, it is pivotally held about the rotatably supported on a crankcase of the reciprocating engine shaft 62 and thus pivotally and indirectly supported on the crankcase. The shaft 62 is fixed inter alia by fasteners 80.

Fig. 3 illustrates the operation of the control piston 54 for adjusting the

Lever element 16 and thus to adjust the compression ratio. to

Actuation of the control piston 54, the adjusting device 24 comprises a pin 64 which penetrates the rotatably fixed to the crankcase shaft 62 and is connected to a substantially U-shaped actuating member 66. The shaft 62 penetrating through a corresponding bore 64 and the substantially U-shaped actuating element 66 are integrally formed with each other and by means of an actuator, not shown, magnetically translatable in the direction of movement of the push rod 32 movable. If the actuating element 66 is moved via the pin 64 in the direction of the push rod 32, the actuating element 66 presses the control piston 54 counter to a spring force of a spring element 68 supported on the control piston 54 and on the push rod 32 in the corresponding direction, resulting in a relative movement of the control piston 54 to the push rod 32 results. As a result, the control edges 48, 50 and 52 release the channels 40, 42 and 44, allowing the lubricating oil to flow into or out of the control chambers 34 and / or 36 in the manner outlined.

From this flow of lubricating oil results in an increase in volume and a reduction in volume of the control chambers 34 and 36, which in turn a

Relative movement of the piston 30 and thus the push rod 32 to the control piston 54th results. This relative movement takes place until the channels 40, 42 and 44, the corresponding control edges 48, 50 and 52 of the control piston 54 run over and closed again, whereby the flow of the lubricating oil is stopped and the piston 30 and thus the push rod 32 and thus turn the Lever 16 occupy a predetermined position, whereby a desired compression ratio of the reciprocating engine is set.

A reverse operation of the control piston 54 is effected, for example, in that the actuating element 66 and the pin 64 are switched powerless, whereby the spring element 68 can push the control piston 54 in the direction of the actuating element 66, whereupon the actuating element 66 and the pin 64 of the push rod 32nd move away. In this case, the control edges 48, 50 and 52, the channels 40, 42 and 44 free and the push rod 32 moves in the same direction in the other direction.

It is clear that to adjust the lever member 16 and thus the

Compression ratio of the reciprocating engine only a specification of a desired position of the control piston 54 must be done via a specification of a desired position of the actuating element 66 and the pin 64 and the adjusting device 24 then adjusts automatically until the flow of the lubricating oil is interrupted. An additional operation of the control piston 54 to terminate the adjustment of the actuator 24 is not required. Furthermore, this means that any leaks due to wear, as it can occur over a very long lifetime, is quasi self-compensated by the adjusting device 24. It is merely an adaptation of the specification of the desired position of the control piston 54 and the actuating element 66 and the pin 64 needed. If appropriate, this adaptation can take place via a simple comparison of predetermined desired values with actual values detected by means of detection devices. This ensures a very precise adjustment of the compression ratio over a very long service life of the reciprocating engine and thus the representation of a very efficient and fuel-efficient operation derselbigen.

As can be seen from FIG. 3, the actuating element 66 and the control piston 54 are not firmly connected to each other but act via a

arcuate surface 70 of the actuating element 66 together. The center of the arcuate surface is at least substantially on the pivot axis of the adjusting device 24, which coincides with the central axis of symmetry of the shaft 62. The arcuate surface 70 ensures a constant stroke and thus a constant movement of the control piston 54 even during a movement or at a Pivoting the adjusting device 24 about its pivot axis, wherein the control piston 54 carries out this pivoting movement while the actuating element 66 is rotationally fixed as described. To improve the contact conditions between the control piston 54 and the arcuate surface 70, the control piston 54 has a rounded head which abuts the arcuate surface 70 and can slide along it with little friction.

To illustrate the executed relative movement of the cylinder 28 and thus of the control piston 54 to the actuating element 66, the cylinder 28 has a slot 72 in which the actuating element 66 is arranged.

To illustrate a simple and inexpensive installation, the cylinder 28 comprises three parts 74, 76 and 78, the part 74 being connected to the part 76. The part 78 is also connected to the part 76 and is partially received in the part 76 and limited on the one hand the working space 26th

Fig. 6 shows the adjusting device 24 in five different from each other

Positions for the representation of five different rotational positions of the lever member 16 relative to the respective crank pin 14 and for representing five different compression ratios of the reciprocating engine. According to illustration A, the adjusting device 24 is in the upper end positions shown in FIGS. 1 to 5, in which the lowest compression ratio is present, which is, for example, ε = 7.

As shown in Figure B, there is a larger amount of lubricating oil in the control chamber 34 than in the illustration A, while there is a small amount of lubricating oil in the control chamber 36. Accordingly, the piston 30 and thus the push rod 32 has moved away from the shaft 62. By this movement, the compression volume decreases in the corresponding cylinder of the reciprocating engine, since the push rod 32, the lever member 16 in a different rotational position relative to the

Hubzapfen 14 presses, wherein this rotational movement via the connecting rod 18 in a

translational movement of the piston is converted in the cylinder. According to illustration C, a compression ratio of ε = 9.5 is set. In comparison, this is

Compression ratio at the setting shown in FIG

Regulating device 24 again slightly less, while the compression ratio in the position shown in illustration E of the adjusting device 24 ε = 14. It can be seen that now a particularly large amount of lubricating oil is received in the control chamber 34, while the control chamber 36 contains almost no more lubricating oil. The overview 6, the remaining reference numerals have been omitted, the analogous to the adjustment device 24 according to the preceding figures being analogous to the adjusting device 24 according to FIG. 6.

The crank mechanism 10 of the reciprocating engine now makes it possible for the lever elements 16 to be independently of one another by means of the respective associated setting device 24 for setting the respective lever element 16 corresponding to the respective one

Compression ratio can be adjusted in respective, different rotational positions relative to the respective corresponding crank pin 14.

This makes it possible to create conditions in the corresponding to the respective lever member 16 cylinder of the reciprocating engine, which are either at least almost optimal for a fired operation of the cylinder, in which fuel is introduced into the cylinder, or at least almost optimally for a are not fired operation of the corresponding cylinder, in which no fuel is introduced into the cylinder and this in one

Push mode is operated. This favors a very efficient and

low-fuel consumption operation of the reciprocating engine, since compromises with respect to the adjustment of the lever members 16, as they would be necessary with a simultaneous adjustment of all lever members 16, are not necessary, but the lever elements 16 rather independent of each other and thus can be set individually for each cylinder.

If in the present reciprocating engine, for example, fuel is introduced into two cylinders corresponding to two of the lever elements 16, while no fuel is introduced into two other cylinders corresponding to the other lever elements 16, then the lever elements 16 corresponding to the cylinders can be injected with no fuel is set so that there is a low compression ratio, while the lever members 16 corresponding to the cylinders, into which fuel is introduced and in which combustion is performed, can be set so that one in particular relative to the compression ratios of the other cylinder high compression ratio is present.

The reduction of the compression ratio in the cylinders, in which no fuel is introduced, which are therefore operated in a non-fired operation, resulting in that less compression work to be done nhuss, resulting in a lower friction and thus lower losses of the reciprocating engine result. This favors the efficient operation of the reciprocating engine. By introducing fuel into the other of the cylinders, an exhaust aftertreatment device associated with the reciprocating engine may be maintained at operating temperature during a relatively long duration overrun of the reciprocating engine, thereby cleaning exhaust gas of the reciprocating engine in a fired operation subsequent to overrun operation the reciprocating engine is possible at least almost instantaneously. This keeps the emissions and in particular the exhaust emissions of the reciprocating engine in a very small frame.

Claims

claims

Method for operating a reciprocating piston engine, in which at least one lever element (16) mounted on a crankpin (14) of a crankshaft (12) and connected to a corresponding connecting rod (18) is adjusted by means of a corresponding adjusting device (24) for adjusting the

Compression ratio of the reciprocating engine between at least two rotational positions relative to the crank pin (14) is set,

characterized in that

at least two lever elements (16) mounted on a respective crankpin (14) and each with a corresponding connecting rod (8) by means of an associated adjusting device (24) independently of each other for setting the compression ratio in respective, different from each other

Rotary positions are adjusted relative to the respective corresponding crank pin (14).

Method according to one of claims 1 or 2,

characterized in that

in a coasting operation and / or in an idling operation of the reciprocating engine by adjusting at least one lever element (16) to the one

Lever element (16) corresponding compression ratio is reduced and by adjusting at least one further lever element (16) to the at least one further lever element (16) corresponding compression ratio is increased.

Method according to one of the preceding claims,

characterized in that

in at least one corresponding to one of the lever elements (16)

Working space, in particular cylinder, the reciprocating engine fuel the Hubkolbenmaschine introduced, in particular injected, and a

Fuel supply in at least one further to a further of the lever elements (16) corresponding work space, in particular cylinder, the

Reciprocating engine is stopped.

4. Process according to claims 2 and 3,

characterized in that

Fuel in the working space, in particular cylinder, introduced, in particular injected, is, which corresponds to the lever element (16), by the setting of the corresponding compression ratio is increased,

5. The method of claim 3 or claim 4 in its reference back to

Claim 3,

characterized in that

first into the at least one to the one of the lever elements (16)

corresponding working space of the reciprocating engine fuel the

Hubkolbenmaschine introduced, in particular injected, and the

Fuel supply in the at least one further to the one further of the lever elements (16) corresponding working space of the reciprocating engine terminated and after a predetermined period of time, in particular in a

Push operation and / or idling operation of the reciprocating engine, the

Fuel supply in the at least one to the one of the lever elements (16) corresponding working space of the reciprocating engine terminated and introduced fuel into the at least one further to the one further of the lever elements (16) corresponding working space, in particular injected, is.

6. The method according to any one of the preceding claims,

characterized in that

the respective lever element (16) via a threaded spindle of the adjusting device (24) and / or by a hydraulic actuation of the adjusting device (24) is set.

7. The method according to any one of the preceding claims,

characterized in that

the respective lever element (16) by an at least substantially translational movement of the adjusting device (24) between the at least two rotational positions is set.

8. The method according to any one of the preceding claims,

characterized in that

the respective lever element (16) is adjusted via a piston (30) of the adjusting device (24) that is displaceably received axially relative to the cylinder (28) in a working chamber (26) of a cylinder (28) and connected to a rod (32).