WO2012013264A1

WO2012013264A1 - Method for operating a reciprocating piston engine

Info

Publication number: WO2012013264A1
Application number: PCT/EP2011/002892
Authority: WO
Inventors: Marc Wodischek; Simone NOWAK; Bernd-Heinrich Schmitfranz; Tilmann RÖMHELD; Michael Wagenplast; Dieter Nowak
Original assignee: Daimler Ag
Priority date: 2010-07-28
Filing date: 2011-06-11
Publication date: 2012-02-02
Also published as: DE102010032488A1

Abstract

The invention relates to a method for operating a reciprocating piston engine, in particular for a motor vehicle, in which a compression ratio of at least one cylinder of the reciprocating piston engine, in which a piston (30) is received so as to be guided in a translatorily moveable manner, is set by means of a servomechanism (38) corresponding to the cylinder, wherein the reciprocating piston engine, which is in a deactivated operating state, is activated with a set compression ratio which is increased with respect to a previous compression ratio that was set in a previous, activated operating state of the piston engine. According to the invention, upon an activation of the reciprocating piston engine that is in operation with a set compression ratio of the cylinder, a compression ratio that is different therefrom is also set, which ratio is at least substantially maintained upon an activation of the reciprocating piston engine following the deactivation.

Description

Method for operating a reciprocating piston engine

The invention relates to a method for operating a reciprocating piston engine according to claims 1 and 5.

DE 199 55 250 A1 discloses a method for monitoring the function of a

Device for variably adjusting the cylinder compression in a reciprocating internal combustion engine. Before and after activation of the cylinder-compression-varying device, an engine operating parameter responsive to a change in cylinder compression is determined, wherein both values of the engine operating parameter are compared with each other to determine whether a change in the engine operating parameter

Engine operating parameters has occurred. A change in the engine operating parameter is an indication of a correct function of the device for the variable adjustment of the cylinder compression.

From WO 01/34948 A1 a method for controlling the cylinder compression during the starting phase of an internal combustion engine is known as known, which is equipped with a device for changing the compression end pressure. Before the

Switching on a starter of the internal combustion engine, one or more criteria for a difficult starting the machine are checked. If at least one criterion for a difficult starting is met, then the cylinder compression in at least one cylinder is reduced to a predetermined minimum value until the engine speed has been increased to a defined threshold, in which case the cylinder compression is increased.

EP 1 431 559 A2 shows an air intake control device for an engine having a mechanism for variably adjusting an amount of intake air which variably controls an amount of fresh air flowing into the engine and a motor

Mechanism for variably setting a compression ratio, which includes Compression ratio of the engine variable controls. Sensors record operating conditions of the engine as well as the compression ratio. Further, a control device is provided, which is designed with the sensors, the mechanism for variably adjusting the amount of intake air and with the mechanism for variable

Adjustment of the compression ratio to be connected to control the mechanism for the variable adjustment of the amount of intake air based on the compression ratio and on the operating conditions of the engine.

DE 38 25 369 C1 discloses a device for controlling the

Compression ratio of an internal combustion engine, with a mechanism for changing the compression ratio of the internal combustion engine, at least between a first higher and a second lower stage, corresponding to

Machine operating conditions, and with a compression ratio measuring device for determining the current compression ratio. The device contains a

Sensor error detection device for detecting a malfunction of

Compression ratio measuring device and a protective device for changing and maintaining the compression ratio at the lower level, when the

Sensor error detection means a malfunction of

Compression ratio measuring device detects.

DE 10 2004 031 288 A1 discloses an internal combustion engine with a

map-controlled, variable compression ratio, which at least one

Load detection, a load request detection and an actuator for adjusting the compression ratio comprises. Further, a motor controller is provided, which is in communication with a time signal generator, wherein the engine control for the

Determining the variable compression ratio to be set in an area of the internal combustion engine has signal lines for detecting at least part of the engine load. The internal combustion engine further comprises a in the

Engine control integrated comparator, which out of the over the signal lines

transmitted signals concerning at least the load in comparison with at least values from a predeterminable map an optimized compression ratio determined.

DE 102 58 872 A1 discloses a method for operating a multi-cylinder

A variable compression ratio internal combustion engine in which starting of the internal combustion engine is performed at a compression ratio that is opposite

Compression ratios is reduced during normal operation of the internal combustion engine. The known reciprocating engines and methods for operating

Reciprocating engines have potential to reduce the energy consumption of the reciprocating engine.

It is therefore an object of the present invention to provide a method for operating a reciprocating engine, which allows a reduced energy consumption of the reciprocating engine.

This object is achieved by a method for operating a reciprocating piston engine having the features of patent claim 1 and by a method for operating a reciprocating piston engine having the features of patent claim 5. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the dependent claims.

The first aspect of the invention relates to a method for operating a

Reciprocating engine, in particular for a motor vehicle, in which a

Compression ratio of at least one cylinder of the reciprocating engine, in which a piston is guided translationally movable, by means of a to the cylinder

corresponding adjusting device is set.

According to the invention, it is provided that the reciprocating piston engine, which is in a deactivated operating state, is activated with a set compression ratio, which is opposite a preceding one, in particular directly

previous, activated operating state of the reciprocating engine set compression ratio is increased.

Starting the reciprocating engine with the increased compression ratio allows a so-called quick start of the reciprocating engine, especially if it is designed as an internal combustion engine, during their operation in the cylinder run combustion processes. Such a quick start or such

Quick start function means that fuel is introduced into the cylinder and in particular directly injected and ignited, wherein the high compression ratio starting enables the generation of a high force for starting and thus the starting process of the reciprocating engine can be completed very quickly. This is especially in a so-called start / stop operation of

Reciprocating advantageous, in which to save fuel the

Reciprocating engine automatically deactivated, for example, when stopping the motor vehicle at a traffic light and automatically activated again when starting or immediately before starting. The described quick start function, in particular by starting with the increased compression ratio allows a particularly fast starting of the deactivated internal combustion engine, whereby a

undesirable long standing at the traffic lights is avoided.

In the pre-deactivated state, activated operating state, so for example when reaching the traffic light, which requires a stop of the motor vehicle, the reciprocating engine, for example, with respect to the subsequent startup, i. opposite to the subsequent activation of the

Internal combustion engine, lower compression ratio to be operated or operated in order to realize an efficient, low-emission and energy consumption, especially fuel consumption, operation of the reciprocating engine, wherein the reciprocating engine or the compression ratio of the cylinder is adapted to the present operating point of the reciprocating engine as needed.

If the reciprocating piston engine located in the activated operating state with this compression ratio is deactivated, in particular automatically deactivated during start / stop operation, then it may be advantageously provided that the compression ratio with which the reciprocating piston engine is activated in the deactivated operating state is activated, at the activation preceding the deactivation (when the traffic light is reached) the then in the activated operating state reciprocating engine is set. In other words, even when the internal combustion engine is deactivated, a compression ratio which is higher than the previously activated operating state is set, which then also exists during the deactivated operating state following the activated operating state and during the subsequent start (activation). This means that the desired high or higher compression ratio when starting the internal combustion engine does not have to be set during the starting process, but already exists, since it has already been set in advance. Thereby, the starting process and in particular the quick start can be performed in a very short time and the reciprocating engine can be started very fast. A realized by the adjustment of the compression ratio according to the invention when activating the reciprocating engine oxygen excess in the cylinder additionally ensures a rapid heating in the flow direction of an exhaust gas of the reciprocating engine, which is ejected from the cylinder through the piston, downstream of the reciprocating engine arranged catalyst so that this particular quickly reaches an advantageous operating temperature (light-off temperature) and can clean the exhaust gas. In this way, the harmful emissions of the reciprocating engine can be kept very low and even in time very early after starting derselbigen.

It should be noted at this point that the reciprocating engine preferably has a plurality, i. at least two cylinders, in each of which a piston is received translationally movable and which is associated with at least one adjusting device for adjusting the respective compression ratio of the cylinder. This allows a cylinder-individual, variable, controlled or regulated, gradual or continuous adjustment of the respective compression ratios. The

Cylinder-specific adjustment of the compression ratios means that each of the compression ratios set for themselves and thus the cylinder can be adjusted very precisely and as needed to the current operating point of the reciprocating engine. In this case, the compression ratio of a cylinder can be set individually and independently of the other compression ratios of the other cylinder. So it is possible that at least two

Compaction conditions of the cylinders differ from each other and the

Reciprocating engine can be operated with at least two different compression ratios. From the cylinder-specific setting of the

Compression ratio at which each cylinder is optimally suited to the

Present operating point of the reciprocating engine, for example, also in response to a present clock of the cylinder or the piston, adapted and

is set accordingly, results in a particularly efficient, low-emission and energy consumption, especially low fuel consumption, operating the

Reciprocating engine.

In a further advantageous embodiment of the invention, which is in the activated operating state reciprocating engine is deactivated with a set compression ratio, which is increased compared to a set in the deactivated operating state compression ratio. This is one

Quick stop function with a relatively high compression ratio realized to the Reciprocating engine starting from the activated operating state particularly fast ie within a particularly short period of time to disable. This keeps a restless behavior of the reciprocating engine in the deactivation, which is referred to as Abstellruckeln, low, so that the reciprocating engine has a particularly high smoothness in their deactivation. This benefits the comfort of occupants of the motor vehicle.

In a further advantageous embodiment of the invention, the

Reciprocating deactivated or activated with a set compression ratio, which is at least temporarily set or can be set even in an activated operating state of the reciprocating engine. The

Reciprocating machine advantageously has a plurality of adjustable

On the one hand to perform a particularly efficient, low-emission and low-energy operation of the reciprocating piston engine as well as the described start and / or stop functions for implementing the quick start function or the quick stop function, with the set to be

Compression ratios during normal operation, ie during the activated operating state of the internal combustion engine, can be adjusted and can be used to represent a very efficient operation of the reciprocating engine. In the case of deactivation and / or activation

Compression ratios are therefore not special

Densification conditions, only for activating and / or deactivating the

Reciprocating engine can be adjusted or adjusted. Rather, these can also be set during activated operating state, so that the range of compression ratios to be set is particularly large. Thus, a very high flexibility is created to adapt the reciprocating engine to a variety of different operating points to represent efficient operation.

Due to the described and due to the inventive setting of

Compression ratio advantageous to be performed quick start function of

Reciprocating engine is a separate starting device, in particular a starter, not required for activating the reciprocating engine or must not be used because the reciprocating engine can be activated by the quick start function as a result of the introduction of fuel into the cylinder and the ignition desselbigen without further starting device. This keeps the weight of the motor vehicle in a small frame and helps to avoid or solve package problems, especially in a space-critical area such as an engine compartment of the motor vehicle. Nonetheless Of course, be provided that the car such a starting device, in particular a starter includes, which is used when activating the reciprocating engine in the presence of certain conditions or can be to activate the reciprocating engine.

A further advantage of the activation of the reciprocating engine with the compression ratio increased compared to the previously activated operating state is that the oxygen surplus in the cylinder gives rapid heating of the cylinder, which is also referred to as the combustion chamber, and thus of the reciprocating engine. This leads to a rapid heating of a lubricant, in particular a lubricating oil, the reciprocating engine, which in turn results in low friction and thus low losses of the reciprocating engine, especially when activating and during a starting phase. This keeps energy requirements low, especially during the starting phase of the reciprocating engine, which is low

Fuel consumption and low C0 ₂ emissions.

The second aspect of the invention relates to a method for operating a

Reciprocating engine, in particular for a motor vehicle, in which a

Compression ratio of at least one cylinder of the reciprocating engine, in which a piston is taken translationally guided, is adjusted by means of a corresponding actuator with the cylinder. According to the invention it is provided that with a deactivation of the set with a

Compression ratio of the cylinder in operation reciprocating engine on the other hand, a different compression ratio is set, which in a subsequent to the deactivation, in particular directly

subsequent, activation of the reciprocating engine is at least substantially maintained. Advantageous embodiments of the first aspect of the invention are to be seen as advantageous embodiments of the second aspect of the invention and vice versa.

The second aspect of the invention allows a particularly good and needs-based and especially fast starting or activating the reciprocating engine out of its deactivated operating state, since the advantageous for activating the reciprocating engine in the presence of certain conditions compression ratio is already set in the previous deactivation or was and thus in the

Activation is present at least almost without delay. In other words, the compression ratio does not have to be set when activating the reciprocating engine be, which would undesirably prolong the starting process, but the desired and adapted to a desired starting behavior of the reciprocating engine compression ratio is already present.

Thus, depending on existing conditions, driver's request, operating state of the reciprocating engine or the motor vehicle and / or the like different starting functions of the reciprocating engine can be realized. If an already described with respect to the first aspect of the invention, so-called quick start function of

Hubkolbenmaschine be realized, so can at the deactivation of the

Reciprocating engine increased compared to the activated operating state

Be set compression ratio, thus the reciprocating engine without use of any existing, separate starting device only by introducing or injecting fuel into the cylinder and ignition desselbigen to start particularly quickly.

Another possible starting function is, for example, to start the reciprocating engine with a separate starting device, in particular a starter. Then it is particularly advantageous, a relation to the compression ratio of the in operation, ie in activated operating state, located reciprocating engine increased

Set compression ratio that then at least almost instantaneously when activating, i. at the transition from the deactivated to the activated operating state of the reciprocating engine, is present. The activation with a relatively low

Compression ratio keeps the force required to start the reciprocating engine low, so that the starter has to muster a small force the

Start reciprocating engine. This results in a low energy requirement of the

Starter, which goes hand in hand with energy and thus fuel savings.

If the reciprocating piston engine comprises such a separate starting device, in particular a starter, then in the context of the first and the second aspects of the invention, depending on the type of start, for example by a driver's request

Operating state of the reciprocating engine and / or the like can be specified, the reciprocating engine can be started either by means of the starting device or without the aid of the starting device and only by injecting and igniting fuel in the cylinder. In all respects, the methods according to the invention enable a fast, at least almost delay-free, comfortable and therefore very good start and stop behavior of the reciprocating piston engine, and a particularly efficient behavior of the same during activation or deactivation. Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and with reference to the drawing. The features mentioned above in the description and

Feature combinations as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures are not only in the respectively indicated combination but also in others

Combinations or alone, without departing from the scope of the invention.

The drawing shows in:

Fig. 1 a detail of a schematic side view of a crank mechanism for a reciprocating engine with a plurality of cylinders and the cylinders associated pistons, wherein by means of the crank mechanism respective compression ratios of the cylinder cylinder individually independently adjustable; and

Fig. 2 shows a detail of a schematic side view of the crank mechanism according to

Fig. 1 with a schematic diagram for detecting a position of a

Control piston of an adjusting device for adjusting the

Compression ratio, wherein based on the detected position of the control piston, the set compression ratio of the corresponding cylinder is determined.

Fig. 1 shows a crank mechanism 10 for a reciprocating engine of a motor vehicle, wherein the reciprocating piston engine comprises a plurality of cylinders. For the sake of clarity, the crank mechanism 10 will be described with reference to FIG. 1 with respect to one of these cylinders corresponding to the crank mechanism 10 of the reciprocating piston engine. It is understood that the description of the crank mechanism 10 and the cylinder is analogous to the other cylinders of the reciprocating piston engine, in particular all others.

The crank mechanism 10 comprises a crankshaft 12, which has main bearing points, via which the crankshaft 12 is mounted in a crankcase of the reciprocating engine. Furthermore, the crankshaft 12 crank webs, of which such a crank arm 14 is shown in FIG. 1. In addition, the crankshaft 12 crank pin, of which a crank pin 16 is shown in FIG. The crankpin 16 corresponds to a cylinder of the reciprocating engine. In the same way, the other crank pin correspond respectively to a cylinder of

Reciprocating engine.

Furthermore, the crank operation 10 includes a transverse lever 18, which is a first

Lever element 20 and a second lever element 22 includes, which are connected to each other, for example, screwed together, are. The transverse lever 18 is rotatably mounted on the crank pin 16 relative to this about an axis of rotation 25 and performs strokes in a rotation of the crankshaft 12, for example, during operation of the reciprocating engine, with out.

The transverse lever 18 has a first bearing 24, on which a connecting rod 26 of the crank mechanism 10 is articulated. In this case, the connecting rod 26 can rotate about a rotation axis 28. As can be seen from FIG. 1, the axis of rotation 28 is spaced from the axis of rotation 25 in the radial direction of the crank pin 16 by a first lever arm n.

The crank mechanism 10 also includes a piston 30, which corresponds to the cylinder, to which the crank pin 16 corresponds, and in which the piston 30 is received translationally movable. The piston 30 is pivotally connected to the connecting rod 26 via a further bearing 32. Attached is the piston 30 to the connecting rod 26 via a piston pin, which in the piston 30 by a corresponding

Circlip is secured in the axial direction of the piston pin. If the piston 30 is moved translationally in the cylinder as a result of combustion processes, this translational movement is converted via the connecting rod 26, the transverse lever 18 and the crankpin 16 into a rotational movement of the crankshaft 12.

The transverse lever 18 has a further bearing 34, on which a control piston 36 of an adjusting device 38 of the reciprocating engine articulated and with the

Cross lever 18 is connected. In this case, the control piston 36 can rotate about an axis of rotation 40 of the bearing 34. The axis of rotation 40 is spaced by a further lever h ₂ in the radial direction of the crank pin 16 of the rotation axis 25. It can be seen that the levers and h ₂ differ in terms of amount. The lever h ₂ is larger than the lever h ^. It is equally possible that the lever and h ₂ are equal in magnitude, or the lever h is greater than the lever H _2. In addition to

Control piston 36, the adjusting device 38 comprises a housing 41 through which a cylinder is formed. In the cylinder, the control piston 36 is held translationally guided guided. By supplying or removing a working medium into the cylinder, For example, compressed air, hydraulic fluid or the like, the control piston 36 can be moved translationally in accordance with a direction arrow 43 and with respect to the housing 41 according to a direction arrow 44 extended or retracted according to a direction arrow 46. In contrast to such an active attitude is also a passive one

Adjustment possible, in which the control piston 36 is moved as a result of gas and inertial forces of the reciprocating engine, which act on the piston 30 on the control piston 36. The control piston 36 is released by the working fluid and valve means, for example check valves which are connected via other control valves, for example, a control slide with control edges which lines for the working fluid release or obstruct, in a desired direction of movement and opposite in the desired direction of movement

Movement direction blocked or completely held. It is a kind of hydraulic freewheel. This embodiment has the advantage that a desired compression ratio can be set without and with only a very small additional energy input. It is also possible to actuate the control piston 36 by means of an electromagnet.

If the crankshaft 12 rotates, the crank pin 16 moves up and down, which also leads to a movement of the transverse lever 18. The adjusting device 38 also moves by the housing 41 pivotable about a pivot axis 42 at a

Adjusting device 38 surrounding housing, for example, on a crankcase of the reciprocating engine, is mounted.

If the control piston 36 is moved translationally according to the directional arrow 43, this leads to a rotation of the transverse lever 18 relative to the crank pin 16 according to a directional arrow 48, whereby the compression ratio of the corresponding cylinder can be adjusted. In this case, the adjustment of the control piston 36 acts on the ratio of the lever and h _{2 to} the same extent, reinforced or reduced. In other words, the adjustment of the control piston 36 leads to an adjustment or adjustment of the top dead center of the piston 30 in the cylinder and thus to an adjustment or adjustment of the compression volume v _{c of} the corresponding cylinder. The adjustment of the control piston 36 also affects the stroke and thus the stroke volume v _{H of} the piston 30. The stroke volume v _H reduces as the flow increases

Compression ratio, which is desirable in terms of the downsizing concept. This results in a corresponding compression ratio, which is also referred to as ε. As already indicated, advantageously, each of the cylinders of the reciprocating engine associated with such a control device 38, by means of which the compression ratio of the corresponding cylinder can be adjusted independently of the other cylinders. This cylinder-specific adjustment of the corresponding compression ratios allows a very precise and extremely needs-based adjustment of

Reciprocating engine to present operating points, so that the reciprocating engine very efficient, low emissions and energy consumption, in particular

low fuel consumption, can be operated.

For precise and needs-based adjustment of the compression ratio, it is desirable to determine the set compression ratio and

if necessary check. This is possible, for example, in which the position of the control piston 36 relative to a reference point and / or the distance covered during the movement of the control piston 36 way, so the stroke of the control piston 36 to detect, and starting therefrom, inter alia, in dependence on the levers hh and h ₂ , the connecting rod 26, etc. on the set compression ratio infer or determine this. A position or the stroke of the control piston 36th

characterizing signal can then be used to control or regulate the

Compression ratio can be used to adjust this variable, continuously or stepwise.

This is illustrated by the schematic diagram in FIG. 2. A schematically illustrated in FIG. 2 sensor 50 detects the position of the control piston 36 and a

Control rod this relative to a reference point and / or the stroke of the control piston 36 and a position and / or the stroke characterizing signal. This signal is transmitted according to a directional arrow 52 to a position control 54 of a control device 56, wherein the control device 56 is formed, for example, as a control unit of the reciprocating engine. The control device 56 further comprises a combustion control 58, by means of which the combustion processes in the cylinders of the reciprocating engine are controlled or regulated. Considering that

Combustion control 58, inter alia, a feedback 60 of the set actual compression ratio, which is determined by the position control 54 based on the signal detected by the sensor 50 and thus based on the position of the control piston 36. For adjusting the compression ratio and for adjusting desselbigen transmitted to an operating point of the reciprocating engine transmits the

Combustion control 58, a preset 62 of a target compression ratio to the position control 54, the target compression ratio in a position to be set of the control piston 36 transferred. For this purpose, the position control 54 also takes into account any other system variables 64 of the crank mechanism 10 and the

Reciprocating engine.

The determined position for setting the desired compression ratio or a position of the control piston 36 characterizing signal is transmitted to a control 65 for the control device 38, which transmits corresponding control signals to an actuator 66, by means of which the control piston 36 moves and thus the

Compression ratio is set.

FIG. 3 shows a possibility of detecting the or at least one position of the control piston 36. For this purpose, the sensor 50 is designed as a Hall sensor with a detection part 68 which cooperates with an arcuate bipolar encoder plate 70 of the Hall sensor. The detection part 68 is, for example, fixed to the

Cranking 10 surrounding crankcase of the reciprocating engine attached while the bipolar encoder plate 70 is fixedly connected to the control piston 36. Since during operation of the reciprocating engine to pivot the adjusting device 38 about the pivot axis 42 according to a direction arrow 72, the encoder plate 70 is curved, wherein the center of the curvature is advantageously on the pivot axis 42. Thus, angle errors can be kept at least very low and it is a very precise detection of the position and / or the stroke of the

Control piston 36 allows. Also, the magnetic field of the encoder plate 70 is

accordingly formed curved.

The control piston 36 is designed, for example, as a hydraulic piston and can be actuated such that the cylinder, with which the cylinder formed by the housing 41 is acted upon by hydraulic fluid, ie the hydraulic fluid is supplied to the housing or removed. The supply of hydraulic fluid into the cylinder or out of the cylinder can be controlled or regulated, for example via an electromagnet, which has particularly fast switching times, so that the

Compression ratio particularly fast to changing operating points of

Reciprocating engine can be adjusted.

It is also possible that the control piston 36 is designed as an electromagnet or at least partially as part of such an electromagnet, so that the

Control piston 36 can be compacted very quickly to set the compression ratio. Furthermore, it is possible that the control piston 36 is designed as a pneumatic piston and is actuated by supply or discharge of compressed air in or out of the cylinder. The supply or discharge of compressed air can also be controlled or controlled by an electromagnet, which has particularly short switching times and allows the fast operation of the control piston 36.

In addition, it is possible that the control piston 36 is actuated by means of a gear, in particular a pinion, the control piston 36 is at least partially formed as a rack with a toothing for actuating the control piston 36 with a corresponding toothing of the gear, in particular the Ritzels, cooperates.

Another possible embodiment is that the control piston 36 is actuated by means of a cam, wherein the control piston 36 is at least partially formed as a rod, which with the cam for actuating the control piston 36th

interacts.

At a distance, the control piston 36 can at least partially be designed as a spindle and be actuated by means of a ball screw to set the

Compression ratio.

Daimler AG

LIST OF REFERENCE NUMBERS

10 crank drive

12 crankshaft

14 crank arm

16 crank pins

18 cross levers

20 lever element

22 lever element

24 storage location

25 axis of rotation

26 connecting rods

28 axis of rotation

30 pistons

32 storage location

34 storage location

36 control piston

38 adjusting device

40 axis of rotation

41 housing

42 pivot axis

43 directional arrow

44 directional arrow

46 directional arrow

48 directional arrow

50 sensor

52 directional arrow

54 position control

56 control device

58 combustion control feedback

specification

system sizes

control

actuator

lever

Claims

claims

Method for operating a reciprocating piston engine, in particular for a motor vehicle, in which a compression ratio of at least one cylinder of the reciprocating piston engine, in which a piston (30) is received translationally guided, by means of a corresponding to the cylinder

Adjusting device (38) is set,

characterized in that

which is activated in a deactivated operating state reciprocating engine with a set compression ratio, which is increased compared to a previous, activated operating state of the reciprocating engine set compression ratio.

Method according to claim 1,

characterized in that

which is in the activated operating state of the reciprocating engine is deactivated with a set compression ratio, which is increased compared to a set in the activated operating state compression ratio.

Method according to one of claims 1 or 2,

characterized in that

the compression ratio with which in the deactivated

Operating state-located reciprocating engine is activated, is set in an activation of the previous deactivation of located in the previous, activated operating state reciprocating engine.

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

characterized in that

the reciprocating engine is deactivated or activated with a set compression ratio, which also in an activated operating state of

Reciprocating engine is set at least temporarily.

5. A method for operating a reciprocating engine, in particular for a

Motor vehicle in which a compression ratio of at least one cylinder of the reciprocating piston engine, in which a piston (30) is received in a translationally guided manner, by means of a corresponding to the cylinder

Adjusting device (38) is set, in particular according to one of the preceding claims,

characterized in that

upon deactivation of the reciprocating engine in operation with a set compression ratio of the cylinder, a contrasting different compression ratio is set, which is at least substantially maintained at an activation of the reciprocating engine following the deactivation.

6. The method according to claim 5,

characterized in that

a versus the compression ratio of the in-service

Reciprocating engine increased compression ratio is set.