DE102018205404B4 - PISTON ARRANGEMENT AND INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

Piston arrangement (1) for an internal combustion engine, comprising: a crankshaft (10) defining a first axis of rotation (A1), the crankshaft (10) having a crank section (11) defining a second crank axis (A2), the second crank axis (A2 ) is offset relative to the first axis of rotation (A1) and extends inclined relative to the first axis of rotation (A1);a piston (20);a piston pin (40) fixed to the piston (20) and inclined relative extends to the second crank axis (A2); anda connecting rod (30) having a first end portion (31) rotatably supported on the piston pin (40) and a second end portion (32) rotatably supported on the crank portion (11) of the crankshaft (10);wherein the second end portion (32) of the connecting rod (30) is slidably mounted on the crank portion (11) along the second crank axis (A2); andwherein the first end portion (31) of the connecting rod (30) is mounted on the piston pin (40) for displacement along the piston pin (40), the piston pin (40) being inclined with respect to the first axis of rotation (A1) and inclined with respect to the second crank axis (A2) extends, and wherein the second crank axis (A2) and the piston pin (40) are inclined in opposite directions of rotation with respect to the first axis of rotation (A1), the connecting rod (30) being displaceable by means of a bearing device (50). is mounted on the crank section (11) of the crankshaft (10), the bearing device (50) having a sliding body (51) sliding on the crank section (11), a coupling body (52) positively connected to the sliding body (51), which is provided for this purpose is to be actuated for movement along the crank portion (11), and a pivot bearing interposed between the slide body (51) and an inner surface (32a) of the second end portion (32) of the connecting rod (30). (53).

Description

Technical field of the invention

The present invention relates to a piston assembly for an internal combustion engine and an internal combustion engine, particularly for a vehicle such as an automobile.

background

It is desirable to reduce the fuel consumption of internal combustion engines, particularly in the automotive sector, for a number of reasons. However, customers also expect a certain level of performance. Attempts have therefore been made to improve the efficiency of internal combustion engines.

One way to improve the efficiency of internal combustion engines is to increase the engine's compression ratio. Compression ratio is commonly defined as the ratio of the volume of a combustion chamber before compression to the volume of the combustion chamber after compression. Here, the volume of the combustion chamber is determined by the position of a piston within a cylinder, the piston being coupled to a crankshaft by means of a connecting rod. While increasing the compression ratio results in increased engine efficiencies, the engine is prone to knocking during high load operation.

To reduce the effects of these conflicting compression ratio requirements, variable compression ratio engines have been proposed. For example, describes the EP 1 496 219 A1 a motor having a connecting rod divided into two sections connected by a pivot, the pivot being axially displaceable by means of a control rod to flexibly adjust the effective length of the connecting rod. WO 2004/015 256 A1 describes a piston arrangement with an inner piston which is slidably mounted in an outer piston. Furthermore describes the EP 2 764 229 B1 a piston assembly having a piston, a connecting rod, and an adjuster having a piston pin coupled to the piston and an eccentric sleeve coupled to the piston pin and the connecting rod.

US 2016/0 256 915 A1 describes an R-Theta device.

the DE 10 2007 017 153 A1 describes a reciprocating internal combustion engine with a variable compression ratio.

the U.S.A. 4,240,386 describes a lifting motor.

Disclosure of Invention

It is one of the objects of the present invention to provide an arrangement which allows flexible adjustment of the compression ratio of an internal combustion engine and which is simple in construction.

This object is achieved by a piston arrangement according to claim 1 and by an internal combustion engine according to claim 5.

Further embodiments of the present invention are the subject matter of the dependent claims and the following description.

One aspect of the invention relates to a piston assembly for an internal combustion engine, particularly for a motor vehicle such as an automobile.

The piston assembly includes a crankshaft, a piston, a piston pin, and a connecting rod.

The crankshaft defines a first axis of rotation and includes a crank portion defining a second crank axis, the second crank axis being offset relative to the first axis of rotation. In particular, a base section of the crankshaft defines the first axis of rotation, wherein a torque can be tapped off at the base section when the piston arrangement is installed in an engine. The crank portion is radially offset from the base portion, that is, perpendicular to the first axis of rotation. The second crank axis extends inclined relative to the first axis of rotation.

The piston is intended to be guided in a cylinder when the assembly is installed in an engine. The plunger pin is attached to the plunger. For example, the piston pin may be located in an interior of the piston defined by a piston skirt and may be attached to the piston skirt. The second crank axis extends inclined relative to the piston pin. That is, the second crank axis extends inclined relative to the first axis of rotation and to the piston pin.

The connecting rod includes a first end portion rotatably attached to the plunger pin is journaled, and a second end portion rotatably journaled to the crank portion of the crankshaft. That is, the connecting rod couples the piston to the crankshaft such that when the piston assembly is installed in an engine, axial movement of the piston is converted to rotational movement of the crankshaft about its first axis of rotation. In particular, the connecting rod may be coupled to the crank portion of the crankshaft and to the piston pin by means of bearing devices, respectively, with the bearing devices each defining an axis of rotation that extends parallel to the first axis of rotation. In particular, the connecting rod may be coupled to the crank portion of the crankshaft and to the piston pin by means of bearing devices, respectively, with the bearing devices each defining an axis of rotation that extends parallel to the first axis of rotation.

It is one of the ideas of the invention to vary the compression ratio by adjusting an effective distance between the piston and the crank portion of the crankshaft by simply sliding the connecting rod along the crank portion, particularly along the second crank axis. Therefore, the second end portion of the connecting rod is slidably supported on the crank portion along the second crank axis, and the first end portion of the connecting rod is slidably supported on the piston pin along the piston pin. That is, the second end portion of the connecting rod is slidably or slidably guided along the second crank axis on the crank portion and the first end portion of the connecting rod is slidably or slidably guided along the pin longitudinal axis on the piston pin. Thus, when the second end portion of the connecting rod is slid along the crank portion of the crankshaft, the first end portion of the connecting rod is caused to move along the pin. Since the second crank axis extends inclined relative to the piston pin, the piston is caused to move toward or away from the crank portion.

The piston assembly of the present invention allows the compression ratio of an internal combustion engine to be varied by simply sliding the connecting rod along the crankshaft. In the piston arrangement according to the invention, in particular the number of moving parts is very small. In particular, no complicated mechanical kinematics are required. The simple construction improves reliability over the life of the piston assembly. By flexibly adjusting the compression ratio, thermal efficiency is increased at low loads, thereby reducing the fuel consumption of an internal combustion engine. Furthermore, the tendency to knock can be significantly reduced at higher loads.

According to one embodiment of the piston arrangement, the piston pin extends parallel to the first axis of rotation. That is, a longitudinal axis of the pin extends parallel to the first axis of rotation. A particularly simple construction of the crankshaft is thereby achieved.

The piston pin extends inclined with respect to the first axis of rotation, the second crank axis and the piston pin being inclined in opposite directions of rotation with respect to the first axis of rotation. According to this embodiment, the longitudinal pin axis is inclined with respect to the first axis of rotation such that it extends inclined in an opposite rotational direction with respect to the second crank axis, particularly when both the piston pin and the second crank axis are on the same side with respect to the first Axis of rotation are arranged. That is, a distance between the piston pin and the crank portion becomes even larger compared to the case where the second crank axis extends parallel to the first rotation axis. Thus, with the same displacement of the connecting rod, an even larger displacement of the piston relative to the crank section can be achieved.

According to one embodiment, an angle between the second crank axis and the piston pin, in particular the longitudinal axis of the pin, is between 5 degrees and 30 degrees.

The connecting rod is movably mounted on the crank section of the crankshaft by means of a bearing device, the bearing device having a sliding body which slides on the crank section, a coupling body which is positively connected to the sliding body and is intended to be actuated for movement along the crank section, and an intermediate pivot bearing inserted between the sliding body and an inner surface of the second end portion of the connecting rod. The pivot bearing thus forms a rotatable connection between the second end section of the connecting rod and the crank section of the crankshaft, and the sliding body provides axial guidance. In particular, the pivot bearing defines a second axis of rotation parallel to the first axis of rotation and allows for rotational movement of the second end portion of the connecting rod relative to the slider. The sliding body is stationary with respect to rotational movement about the second crank axis, but is movable along the second crank axis. The storage device advantageously has a very simple structure.

According to one embodiment, the crank section of the crankshaft has a recess which is covered by the sliding body of the bearing device to form a closed pressure chamber, the coupling body dividing the pressure chamber into a first chamber section and a second chamber section, and the crankshaft having a fluid channel which ending in the first or the second chamber section. According to this embodiment, an actuation structure or an actuation system for moving the coupling body along the crankshaft is realized as a hydraulic system. The coupling body is guided in the pressure chamber formed by a recess of an outer peripheral surface of the crank portion extending along the second crank axis. The coupling body can be displaced by introducing a hydraulic fluid such as oil into one of the chamber portions, thereby increasing the volume of the corresponding chamber portion. Optionally, a second fluid channel can be provided, which ends in the respective other chamber section. One of the advantages of this actuation structure according to this embodiment is that it can be easily integrated into existing internal combustion engine designs, since hydraulic circuits are typically already provided, for example for lubricating, cooling or actuating engine components.

According to a further embodiment, a coil is arranged on the crankshaft at a distance from the coupling body, and the coupling body has a magnetizable or magnetic material. That is, according to this embodiment, an electric actuation system for moving the coupling body along the crankshaft is provided. By applying an electrical voltage to the coil, a magnetic field is generated, which magnetizes the magnetizable material of the coupling body and causes it to move in the direction of the coil. Optionally, the coupling body can also be implemented as a permanent magnet. Depending on the polarity of the electrical voltage applied to the coil, the direction of movement of the coupling body can be varied in a simple manner. The advantage of this solution is that it can be easily retrofitted or replaced.

According to one embodiment, a biasing means biases the bearing assembly to a home position along the crank portion. A starting position corresponds to a position of the second end portion of the connecting rod on the crank portion of the crankshaft, in which the connecting rod sets a predetermined distance, for example a maximum possible distance, between the crank portion and the piston. The home position may be physically defined, for example, by a stop formed on the crank portion. Furthermore, the home position may be defined by a specific volume of hydraulic fluid in one of the chamber portions of the optional hydraulic chamber or by a specific magnetic force generated by the optional spool. The biasing device is designed to apply a force to the bearing device along the second crank axis. For example, the prestressing device can be realized by an elastic part, such as a spring. The provision of a pretensioning device offers the advantage that the bearing section and thus also the connecting rod are reliably moved back into the starting position if an actuating force by which the connecting rod is positioned is unintentionally lost, for example in the event of an unintentional failure of the optional coil or a hydraulic pressure in the optional hydraulic chamber.

According to another aspect of the present invention, there is provided an internal combustion engine having a cylinder and a piston assembly according to any of the embodiments described above.

The cylinder includes a cylinder body defining a stroke axis and a cylinder head disposed at a first end of the cylinder body. The crankshaft is rotatably mounted about its first axis of rotation, for example on a bearing structure such as an engine block. The piston is guided in the cylinder housing along the stroke axis between a top dead center, OT, and a bottom dead center, UT.

In general, the piston and cylinder define a combustion chamber. At TDC, the piston is arranged at a first distance from the cylinder head. At BDC, the piston is spaced a second distance from the cylinder head, the second distance being greater than the first distance. The piston and cylinder define a first volume at piston TDC and a second volume at piston BDC that is greater than the first volume. A compression ratio may be defined by the ratio between the first volume and the second volume. This compression ratio can be easily adjusted by adjusting the position of the connecting rod on the crank portion of the crankshaft.

According to an embodiment of the internal combustion engine, a control device is provided, wherein the control device is configured to indicate the position of the control rod of the second crank axis during the movement of the piston between TDC and BDC by means of an actuator, the actuator causing the connecting rod to be displaced between an initial position at BDC and a setting position at TDC. The first signal can be a crankshaft angle of the crankshaft, for example. The actuator can be formed by the optional coil, for example.

According to a further embodiment, a distance between the starting position and the setting position optionally depends on a second input signal S2. The second signal can be, for example, a load requirement on the crankshaft, a position of a combustion air flap that determines the air/fuel ratio of an air/fuel mixture for the engine, or another state variable of the engine characterizing a load state of the internal combustion engine.

The features described herein for the device are also disclosed for the method and vice versa.

character list

• 1 zeigt eine schematische Schnittansicht eines internen Verbrennungsmotors gemäß einem Vergleichsbeispiel der vorliegenden Erfindung;
• 2 zeigt eine Detail-Schnittansicht des in 1 durch den Buchstaben Z gekennzeichneten Bereichs;
• 3 zeigt eine vereinfachte, schematische Ansicht einer Kurbelwelle einer Kolbenanordnung gemäß einem Ausführungsbeispiel der vorliegenden Erfindung;
• 4 zeigt eine vereinfachte, schematische Ansicht einer Kurbelwelle einer Kolbenanordnung gemäß einem weiteren Ausführungsbeispiel der vorliegenden Erfindung;
• 5 zeigt eine schematische Schnittansicht eines internen Verbrennungsmotors gemäß einem weiteren Ausführungsbeispiel der vorliegenden Erfindung; und
• 6 zeigt ein Diagramm eines thermischen Wirkungsgrads eines internen Verbrennungsmotors abhängig von einem geometrischen Verdichtungsverhältnis des Motors für verschiedene Luft-Kraftstoff-Verhältnisse.

For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in connection with the accompanying drawings. The invention is explained in more detail below with reference to exemplary embodiments that are specified in the schematic figures of the drawings:

• 1 Fig. 12 is a schematic sectional view of an internal combustion engine according to a comparative example of the present invention;
• 2 shows a detailed sectional view of the in 1 area indicated by the letter Z;
• 3 12 shows a simplified, schematic view of a crankshaft of a piston assembly according to an embodiment of the present invention;
• 4 shows a simplified, schematic view of a crankshaft of a piston assembly according to another embodiment of the present invention;
• 5 12 is a schematic sectional view of an internal combustion engine according to another embodiment of the present invention; and
• 6 Figure 12 shows a graph of thermal efficiency of an internal combustion engine versus a geometric compression ratio of the engine for various air-fuel ratios.

In the figures, the same reference numbers designate the same components unless otherwise indicated.

Detailed description of exemplary embodiments

1 shows an example of an internal combustion engine 2 with a cylinder 120 and a piston arrangement 1.

The cylinder 120 has a cylinder housing 121 and a cylinder head 122 . As in 1 As shown, the cylinder housing 121 has an inner surface 121a which extends cylindrically and thereby defines a stroke axis A121 which is also a cylinder axis. At a lower end portion 121A of the cylinder housing 121, the inner surface 121a defines a first opening. At an upper end portion 121B of the cylinder housing 121, which is opposite to the lower end portion 121A, the inner surface 121a defines a second opening.

The cylinder head 122 is arranged at the upper end portion 121B of the cylinder housing 121 and covers the second opening. The cylinder head 122 may include ports for routing valves (not shown), cooling passages (not shown), and similar structures.

As in 1 As further shown, the piston assembly 1 includes a crankshaft 10, a piston 20, a connecting rod 30 and a piston pin 40. FIG.

The crankshaft 10 has a base portion 12 defining a first axis of rotation A1 and a crank portion 11 defining a crank axis A2. The crank portion 11 is offset relative to the base portion 12 such that the crank portion 11 is rotatable about the base portion 12 when the base portion 12 is rotatably supported about the first rotation axis A1. Both the base portion 12 and the crank portion 11 may have a circular cross-section (not shown). As in 1 shown, the base section 12 and the crank section 11 can be connected to one another by a coupling section 13 which extends transversely to the base section 12, in particular transversely to the first axis of rotation A1. As in 1 is shown as an example, the coupling portion 13 can be realized as a disk- or plate-shaped part, wherein the base portion 12 is fixed in a central portion of the coupling portion 13, and wherein the crank portion 11 in an edge portion of the Kopp ment section 13 is attached. As in 1 As shown, the second crank axis A2 extends inclined relative to the first rotation axis A1. A second axis of rotation R2, which extends parallel to the first axis of rotation A1, is defined by an optional bearing device 50, as described in detail below with reference to FIG 5 is explained.

The piston 20 may include a piston skirt 21 and a piston crown 22 . The piston skirt 21 has an inner surface 21a which defines an interior space 121 of the piston 20 and further defines piston skirt 21 openings located at opposite ends of the piston skirt 21 . The piston skirt 21 also has an outer surface 21b which defines an optionally cylindrical periphery of the piston 20 . The piston crown 22 is fixed to an end portion of the piston skirt 21 and covers one of the openings of the piston skirt 22 .

As in 1 As shown, the plunger pin 40 is implemented as an elongate member having a pin longitudinal axis A40 defined by an outer surface of the pin 40 .

The connecting rod 30 is implemented as an elongate member having a first end portion 31 and a second end portion 32, the first and second end portions 31, 32 being located at opposite ends of an elongate lever portion 33 of the connecting rod 30, respectively. Like this in 1 for the first end portion 31 and in 2 is shown for the second end portion 32, the first and the second end portion 31, 32 of the connecting rod 30 may each have a through hole. That is, the first and second end portions 31, 32 each preferably form a sleeve.

As in 1 As shown, the piston pin 40 is attached to the piston 20, specifically, the piston pin 40 may be attached to the piston skirt 21 and extend within the interior space 121 of the piston 20. As in 1 As shown further schematically, the piston pin 40 extends transversely relative to a piston axis defined by the outer surface 21b of the piston skirt 21 . As in 1 is shown, the piston pin 40 can in particular extend parallel to the first axis of rotation A1. In this case, the pin longitudinal axis A40 corresponds to a pin rotation axis R40. According to the invention, the piston pin 40 extends inclined relative to the first axis of rotation A1, as shown in 5 is shown. In this case, the pin axis of rotation R40 is defined by a pin bearing device 70 such that it extends parallel to the first axis of rotation A1, as will be explained in more detail below.

The connecting rod 30 couples the piston 20 to the crankshaft 10 . Furthermore, the second end section 32 of the connecting rod 30 is mounted on the crank section 11 in such a way that it can be displaced along the crank section 11, in particular along the second crank axis A2. Accordingly, the first end section 31 of the connecting rod 30 is mounted on the piston pin 40 in such a way that it can be displaced along the piston pin 40, in particular along the longitudinal axis A40 of the pin.

As in 1 shown, the crank section 11, in particular the second crank axis A2, extends both relative to the first axis of rotation A1 and relative to the piston pin 40, in particular to the longitudinal axis A40 of the pin, with in 1 the pin longitudinal axis extends parallel to the first axis of rotation A.

In a state installed in an internal combustion engine, as exemplified in 1 As shown, the crankshaft 10 is rotatably mounted about its first axis of rotation A1, for example on an engine block (not shown). The cylinder 120 is fixedly positioned with respect to the first rotation axis A1 and arranged such that the lower end portion 121A of the cylinder housing 121 faces the crankshaft 10 . The piston 20, particularly the outer surface 21a of the piston skirt 21, is guided within the cylinder housing 121, particularly by the inner surface 121a of the cylinder housing 121. Generally, the piston is within the cylinder housing 121 along the stroke axis A121 between a top dead center, TDC, and a bottom dead center, UT, out. In 1 the piston 20 is shown at TDC. In this position, a TDC volume is defined by the piston 20, in particular the piston crown 21, the cylinder housing 121 and the cylinder head 122. At TDC, the distance d between the piston 20, in particular between the piston crown 21 and the first axis of rotation A1 of the crankshaft 10, is at its maximum. At TDC, the second crank axis A2 and the longitudinal axis A40 of the pin preferably lie in a common plane and extend at an incline relative to one another. At BDC, the distance d between the piston 20, in particular between the piston crown 21 and the first axis of rotation A1 of the crankshaft 10, is minimal. Therefore, a BDC volume defined by the piston 20, in particular the piston crown 21, the cylinder housing 121 and the cylinder head 122, is larger than the OT volume. A compression ratio may be defined as the ratio between BDC volume and TDC volume.

Since the connecting rod 30 is slidably mounted on the piston pin 40 and the crank portion 11 of the crankshaft, and since the second crank axis A2 extends inclined relative to the piston pin 40, particularly at TDC, the TDC volume can be increased by sliding the second end portion 32 of the connecting rod 30 along of the second crank axis A2 can be adjusted. This shift along the second crank axis A2 also corresponds to a shift along the first axis of rotation A1. In 1 the connecting rod 30, the piston 20 and the piston pin 40 are shown in solid lines in a home position. In order to increase the TDC volume, the connecting rod 30 is displaced by a distance along the second crank axis A2, which corresponds to a displacement of the connecting rod 30 along the first axis of rotation A1 by a distance X1. In 1 this shift corresponds to a movement to the right. The position of the connecting rod 30, the piston 20 and the piston pin 40 in the shifted position are shown in FIG 1 shown in dashed lines. As in 1 As can be seen, a displacement of the connecting rod 30 towards one end of the piston pin 40 causes a movement of the piston relative to the first axis of rotation A1 of the crankshaft 10 due to the inclined arrangement of the second crank section 11 relative to the piston pin 40. In 1 the displacement X1 along the first axis of rotation A1 results in a displacement H1 of the piston 20 along the stroke axis A121. Generally, at TDC, the connecting rod 30 is displaced along the second crank axis A2 in a direction in which a distance between the second crank axis A2 and the first rotation axis A1 increases (in 1 to the left), an increase in the distance d between the piston 20 and the first axis of rotation A1. As a result, the OT volume is reduced and the compression ratio is increased. A displacement of the connecting rod 30 along the second crank axis A2 in a direction in which a distance between the second crank axis A2 and the first rotation axis A1 becomes smaller (in 1 to the right), causes a reduction in the distance d between the piston 20 and the first axis of rotation A1. As a result, the TDC volume increases and the compression ratio decreases.

As in 1 As further shown, the connecting rod 30 is supported on the piston pin 40 by means of a pin bearing device 70 . The pin bearing device 70 has a pin slider 71 and a pivot bearing 72 . As in 2 As shown, the connecting rod 30 is supported on the crank portion 11 of the crankshaft 10 by means of a bearing device 50 . Generally, the pin bearing assembly 70 defines a pin axis of rotation R40 and the bearing assembly 50 defines a second axis of rotation R2, with the pin axis of rotation R40 and the second axis of rotation R2 each being parallel to the first axis of rotation A1.

The pin slider 71 is in sliding contact with the plunger pin 40. The pin slider 71 may be implemented as a sleeve surrounding the pin 40, for example. Optionally, a first guide structure such as a protrusion (not shown) may be formed on an inner surface of the pen slider 71 and a second guide structure such as a groove (not shown) may be formed on an outer surface of the pen. The optional second guide structure extends along the longitudinal axis of the pen and the first guide structure engages the second guide structure. The plunger pin 40 extends through an opening defined by the inner surface of the pin slider 71 . An outer surface of the pen slider 71 defines the pen rotation axis R40. In 1 the pin rotation axis R40 corresponds to the pin longitudinal axis A40. In 5 the pin longitudinal axis A40 extends inclined to the pin longitudinal axis A40.

The pivot bearing 72 is interposed between the pin slider 71 and an inner surface of the first end portion 31 of the connecting rod 30 . In particular, the pivot bearing 72 surrounds the pin slider 71. The pivot bearing 72 is stationary relative to the pin slider 71 and the first end portion 31 of the connecting rod 30 for translational movement along the pin longitudinal axis A40. However, the pivot bearing 72 allows the first end portion 31 of the connecting rod 30 to pivot relative to the pin slider 71 about the pin rotation axis R40.

2 shows a detailed sectional view of the in 1 area marked by the letter Z. As in 2 shown, the connecting rod 30 is mounted on the crank section 11 of the crankshaft 10 by means of a bearing device 50 . In the 2 The bearing device 50 shown as an example has a sliding body 51 , a coupling body 52 and a pivot bearing 53 .

As in 2 shown, the sliding body 52 is in sliding contact with the crank section 11, in particular with an outer surface 11a of the crank section 11. The sliding body 52 can be realized, for example, as a sleeve surrounding the crank section 11, the sleeve optionally consisting of two half-shells 51A, 51B is formed like this in 2 is shown as an example. Optionally, a first guide structure such as a protrusion (not shown) may be formed on an inner surface of the slider body 51 and a second guide structure such as a groove (not shown) may be formed on the outer surface of the crank portion 11 . The optional second guide structure extends ent along the second crank axis and the first guide structure engages the second guide structure.

The coupling body 52 can be realized, for example, as a ring enclosing the crank section 11 . The coupling body 52 is positively connected to the sliding body 51 and is intended to be actuated for movement along the crank portion 11 . For example, an outer end of the coupling body 52 can protrude into a groove 54 formed on the inner surface of the sliding body 51 .

The pivot bearing 53 is interposed between the slider 51 and an inner surface 32a of the second end portion 32 of the connecting rod 30 . In particular, the pivot bearing 53 surrounds the slider body 51. The pivot bearing 53 is stationary relative to the slider body 51 and the second end portion 32 of the connecting rod 30 with respect to translational movement along the second crank axis A2. However, the pivot bearing 53 defines a second pivot axis R2 about which pivotal movement of the second end portion 32 of the connecting rod 30 relative to the slide body 51 is permitted. Since the second crank axis A2 in the 1 and 2 extends inclined to the first axis of rotation A1, the second axis of rotation R2 in the 1 and 2 also inclined to the second crank axis A2.

As in the 1 and 2 As further illustrated, a hydraulic fluid distribution structure can optionally be integrated into the crankshaft 10 . 3 also shows an optional hydraulic actuation system 150.

As in 2 1, to realize the hydraulic fluid distribution structure, the crank portion 11 may have a recess 15 formed on the outer surface 11a of the crank portion 11 and extending along the second crank axis A2. Furthermore, the crankshaft 10 has at least one fluid channel 17A, 17B which ends in the recess 15 of the crank section 15 . As in the 2 and 3 is shown schematically, the at least one fluid channel 17A, 17B extends through the base section 12, the coupling section 13 and the crank section 11. As in FIGS 2 and 3 is shown by way of example, a first and a second fluid channel 17A, 17B can be provided for each crank section 11, the channels 17A, 17B terminating in the recess 15 at a distance from one another with respect to the second crank axis A2.

As in 2 is shown, the recess 15 of the crank section 11 is covered by the sliding body 51 of the bearing device 50 . As a result, a closed pressure chamber 16 is formed. The coupling body 52 divides the pressure chamber 16 into a first chamber portion 16A and a second chamber portion 16B. In particular, the coupling body 52 seals the first and second chamber sections 16A, 16B from one another. The at least one fluid channel 17A, 17B ends in the first or the second chamber section 16A, 16B. In particular, the first and second fluid channels 17A, 17B end on opposite sides of the coupling body 52.

As in 3 shown schematically, the at least one fluid channel 17A, 17B, in particular the first fluid channel 17A, can be connected to a first pressure line 151 of the hydraulic actuation system 150. The optional second fluid channel 17B can be connected to a second pressure line 152 of the hydraulic actuation system 150 . The first and second pressure lines 151, 152 are connected to a source 150 of pressurized hydraulic fluid, such as oil, and carry the hydraulic fluid. The pressure of the hydraulic fluid in the first pressure line 151 can be adjusted using a first pressure valve 153 . The pressure of the hydraulic fluid in the second pressure line 152 can be adjusted by means of a second pressure valve 154 . By adjusting the pressure in the first and second pressure lines 151, 152, the volume of hydraulic fluid contained in the first and second chamber portions 16A, 16B can be increased or decreased. As a result, the position of the coupling body 52 can be varied along the second crank axis A2. For example, when the pressure in the first pressure line 151 is increased over the pressure in the second pressure line 152, additional hydraulic fluid is supplied to the first chamber portion 16A, causing the coupling body 52 to move toward the second chamber portion 16B.

As in the 3 and 4 is shown, the internal combustion engine may further comprise a control device 200 which is set up to control the position of the control rod 30 on the second crank axis A2 during the movement of the piston 20 between TDC and BDC by means of an actuator, the actuator having the Connecting rod 30 is caused to translate between the home position at BDC to the adjusted position at TDC, with a distance along the first axis of rotation A1 between the home position and the set position optionally depending on a second input signal S2. The second input signal S2 can, for example, represent a load requirement that is applied to the crankshaft 10 . For example, corresponds to 1 the position shown in solid lines of the connecting rod 30 of the starting position Connecting rod 30 at BDC and the position of connecting rod 30 shown in dashed lines corresponds to the displaced position of connecting rod 30 at TDC.

The control device 200 can also be integrated into the hydraulic actuation system 150 . The control device 200 is set up to adjust the pressure in the first and the second pressure line 151, 152 in accordance with the input signal S1. For example, the control device 200 is set up to adjust the pressure in the first and the second pressure line 151, 152 such that during the movement of the piston 20 between the TDC and the BDC the coupling body 52 causes the connecting rod 30 to move between the starting position into the shifted position.

4 shows a motor 2 with a piston arrangement 1 with a coil 55, the coupling body 52 having a magnetizable or magnetic material. The coil 55 is arranged on the crankshaft 10 at a distance from the coupling body 52 . For example, the spool may be disposed within the cross section of crank portion 12 or generally on crank portion 12 . In 4 is shown by way of example that the coil is arranged on the optional coupling section 13 of the crankshaft 10 . By applying an electrical voltage to the coil, a magnetic field is generated, which causes the coupling body 52 to move along the second crank axis A2. In this case, the coil 55 forms an actuator for moving the connecting rod 30.

As in 4 shown, the optional control device 200 can also be coupled to the coils 55 as actuators. The control device 200 is set up, according to the input signal S1, to set the polarity and/or the magnitude of the electrical voltage which is applied to the respective coils. For example, the controller 200 is configured to adjust the tension such that during movement of the piston 20 between TDC and BDC, the coupling body 52 causes the connecting rod 30 to move between the home position and the shifted position.

As in the 2 until 4 is further shown, a biasing device may be provided. The biasing device 60 can be realized, for example, as a spring, as is symbolic in FIGS 2 until 4 1 and biases the bearing assembly 50 to the home position along the crank portion 11 .

5 shows an internal combustion engine 2 with a piston arrangement 1. The piston arrangement 1 differs from that in FIG 1 Piston arrangement shown in that the piston pin 40, in particular the pin longitudinal axis A40 extends inclined relative to the first axis of rotation A1 and inclined relative to the second crank axis A2. As in 5 As shown, the second crank axis A2 and the piston pin 40 are inclined in opposite directions of rotation with respect to the first axis of rotation A1. Especially in the OT, as in 5 As shown, the second crank axis A2 and the piston pin 40 are inclined in opposite directions of rotation with respect to the first axis of rotation A1. This course of the piston pin 40, in particular the piston longitudinal pin A40, and the second crank axis A2, which diverges at TDC, offers the advantage that only a small displacement X1 along the first axis of rotation X1 is required for a given displacement H1 of the piston 20 along the stroke axis A121 .

The pin storage device 70 has the same components in the same arrangement as in FIG 1 shown. However, the piston slider 71 is configured similarly to the slider 51. That is, the outer surface of the pin slider 71 defines the pin axis of rotation R40, which is parallel to the first axis of rotation A1 of the crankshaft 10 and parallel to the second axis of rotation A2 extends.

6 1 shows schematically the dependency of the thermal efficiency of the internal combustion engine 2 on the geometric compression ratio for different air-fuel ratios A. As can be seen, the thermal efficiency increases with an increasing compression ratio. By adjusting the compression ratio by sliding the connecting rod 30 as described above, the thermal efficiency can be greatly increased. Since adjustment is possible, knocking can be reliably prevented.

The invention has been described in detail with reference to exemplary embodiments. However, it will be appreciated by those skilled in the art that modifications to these embodiments are possible without departing from the principles and central ideas of the invention, the scope of protection as defined in the claims and the range of equivalency thereto.

Reference List

1

piston assembly

10

crankshaft

11

crank section

11a

outer surface of the crank section

12

base section

13

coupling section

15

recess

16

pressure chamber

16A

first chamber section

16B

second chamber section

17A, B

fluid channel

20

Pistons

21

piston shirt

21a

inner surface of the piston skirt

21b

outer surface of the piston skirt

22

piston crown

30

connecting rod

31

first end portion of the connecting rod

32

second end portion of the connecting rod

32a

inner surface of the second end portion of the connecting rod

33

Lever section of connecting rod

50

storage device

51

sliding body

51A, 51B

half shells

52

coupling body

53

pivot bearing

54

groove

55

Kitchen sink

60

pretensioning device

70

pin storage device

120

cylinder

121

cylinder body

121A

lower end portion of the cylinder body

121a

inner surface of the cylinder body

121B

upper end portion of the cylinder body

122

cylinder head

150

hydraulic actuation system

151

first pressure line

152

second pressure line

153

first pressure valve

154

second pressure valve

155

hydraulic fluid pressure source

200

control device

A1

first axis of rotation

A2

second crank axle

A40

pen longitudinal axis

A121

lifting axis

H1

Displacement of the piston along the stroke axis

121

interior of the flask

R2

second axis of rotation

R40

Pen rotation axis

X1

Displacement of the connecting rod along the first axis of rotation

X2

Distance of displacement of the connecting rod along the second crank axis

A

air to fuel ratio

Claims (7)

Piston arrangement (1) for an internal combustion engine, comprising: a crankshaft (10) defining a first axis of rotation (A1), the crankshaft (10) having a crank section (11) defining a second crank axis (A2), the second crank axis (A2 ) is offset relative to the first axis of rotation (A1) and extends inclined relative to the first axis of rotation (A1); a piston (20); a piston pin (40) fixed to the piston (20) and extending inclined relative to the second crank axis (A2); and a connecting rod (30) having a first end portion (31) rotatably supported on said piston pin (40) and a second end portion (32) rotatably supported on said crank portion (11) of said crankshaft (10); the second end portion (32) of the connecting rod (30) being slidably supported on the crank portion (11) along the second crank axis (A2); and wherein the first end portion (31) of the connecting rod (30) is mounted on the piston pin (40) for displacement along the piston pin (40), the piston pin (40) being inclined with respect to the first axis of rotation (A1) and inclined with respect to the second crank axis (A2), and wherein the second crank axis (A2) and the piston pin (40) are inclined in opposite directions of rotation with respect to the first axis of rotation (A1), the connecting rod ( 30). connected coupling body (52) intended to be operated to move along the crank portion (11) and one inserted between the sliding body (51) and an inner surface (32a) of the second end portion (32) of the connecting rod (30). Pivot bearing (53) has. Piston assembly (1) after claim 1 , wherein the crank section (11) of the crankshaft (10) has a recess (15) which is covered by the sliding body (51) of the bearing device (50) to form a closed pressure chamber (16), the coupling body (52) containing the pressure chamber (16) into a first chamber section (16A) and a second chamber section (16B), and wherein the crankshaft (10) has a fluid channel (17A; 17B) which ends in the first or the second chamber section (16A; 16B). Piston assembly (1) after claim 1 , wherein a coil (55) is arranged on the crankshaft (10) at a distance from the coupling body (52), and wherein the coupling body (52) comprises a magnetizable or magnetic material. Piston assembly (1) according to one of Claims 1 until 3 wherein a biasing means biases the bearing device (50) to a home position along the crank portion (11). Internal combustion engine (2), with: a cylinder (120) having a cylinder body (121) defining a stroke axis (A121) and a cylinder head (122) disposed at a first end of the cylinder body (121); and a piston arrangement (1) according to any one of the preceding claims; wherein the crankshaft (10) is rotatably mounted about its first axis of rotation (A1); and wherein the piston (20) is guided in the cylinder housing (121) along the stroke axis (A121) between a top dead center, OT, and a bottom dead center, UT. Internal combustion engine (2) after claim 5 , additionally comprising a control device (200), wherein the control device (200) is set up to the position of the connecting rod (30) on the second crank axis (A2) during the movement of the piston (20) between the OT and the UT by means of an actuator to control, wherein the actuator causes the connecting rod (30) to a displacement between a starting position in the UT in a setting position in the OT. Internal combustion engine (2) after claim 6 , wherein a distance between the starting position and the setting position optionally depends on a second input signal (S2).

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