WO2015173412A1

WO2015173412A1 - Internal combustion engine having an impact-reducing switching surface for adjusting a variable compression ratio

Info

Publication number: WO2015173412A1
Application number: PCT/EP2015/060795
Authority: WO
Inventors: Uwe Schaffrath
Original assignee: Fev Gmbh
Priority date: 2014-05-15
Filing date: 2015-05-15
Publication date: 2015-11-19
Also published as: DE112015002278A5

Abstract

The invention relates to a reciprocating-piston machine, in particular an internal combustion engine (1), having an adjustable compression ratio and comprising a crankshaft (2), at least a first connecting rod (3), an adjusting mechanism (4) for adjusting the adjustable variable compression ratio, a first switch-over element (5) for adjusting and/or for triggering an adjustment of the adjusting mechanism (4), wherein the first switch-over element (5) is arranged on the first connecting rod (3), and a first actuating element having a first switching surface for transferring the first switch-over element (5) from a first position to a second position and/or vice versa, wherein the switching surface has two different slopes with respect to a reference plane at at least two different points, which reference plane extends perpendicularly to the crankshaft axis, and wherein the two slopes with respect to the reference plane have the same sign.

Description

Combustion engine with shock reducing button for adjusting a variable compression ratio

The present patent application claims priority from German Patent Application 10 2014 007 053.0 of May 15, 2014, the content of which is hereby incorporated by reference into the subject matter of the present patent application.

The invention relates to an internal combustion engine with a variable compression ratio, a crankshaft, at least a first connecting rod, an adjusting mechanism for adjusting the compression ratio, a first switching element for adjusting the adjusting mechanism, wherein the first switching element is arranged on the first connecting rod and a first actuating element with an actuating - or button for transferring the first switching element from a first position to a second position and / or vice versa.

Such an internal combustion engine is known from WO-A-2014/019684, WO-A-2014/019683, DE-A-10 205 055 199, DE-10 2010 016 037 and DE-A-10 2012 014 917. In the internal combustion engine according to WO-A-2014/019684, the first switching element, which is arranged in a lower region of the connecting rod, actuated via a cam member. In this case, the first switching element in the connecting rod and the adjusting mechanism is integrated in an upper region of the connecting rod. Such a constructed connecting rod is sensitive to vibrations during operation of the internal combustion engine. Above all, vibrations can be conducted into the interior of the connecting rod during the transfer of the first switching element via impacts on the cam disk element, where they in particular damage mechanical components of the adjusting mechanism in continuous operation.

The object of the present invention is therefore to provide a reciprocating piston or in particular special internal combustion engine ready to stel len, in which the Vibrati ^¬ on when pressing a switching element of an adjustment mechanism for Verstel len the variable compression of the internal combustion engine are red u ^¬ adorned and / or the operation of the switching element safely and reliably takes place.

This object is achieved according to the invention by an internal combustion engine with the features of patent claim 1. Advantageous embodiments with expedient developments of the invention will become apparent from the remaining claims, the description and the figures.

Logically, t he actuating or mechanical actuating element for mechanical Einwir ^¬ effect on the switching element with different slopes union rather different amounts button is therefore proposed with the invention, but to provide g offset sign. This can be taken into account the fact that the U mschaltelement during a revolution of the connecting rod with different Licher speed speed on the actuation surface moves past. This difference in speed of movement of the switching element can lead, in particular at low rotational speeds, to the fact that the switching element which is thus moved comparatively slowly with the connecting rod is not reliably switched over, or if the rotational speed is high, the actuation of the switching element, which is in th e ^¬ sem case verg facilitated as moving fast, leads to undesirable vibrations and pulses könn- jeopardize the reliability of switching, if necessary, t he th. It is therefore proposed according to the invention, th e pitch of the Betätig ungsfläche in that region in which the switching ungsfläche during its movement past the Betätig a verg facilitated as low Ge ^¬ speed which can vary and select particular g horses as ungsfläche in areas of Betätig , through which the U mschaltelement moves faster during a connecting rod circulation. But there are also fiction, ^¬ possible according to situations where the climbing ungsverhältnisse be chosen inversely to the situation described above. Overall, it can be said be chosen that the choice of the slope and the design of the button to the respective conditions, as found in a reciprocating engine with switching element and switch for changing the compression ratio, adapted.

The different speeds of movement of the switching element during a Pleuelumlaufs ultimately hang together with the fact that the connecting rod in particular at its lower and upper dead center has a much greater rotational speeds than each offset by 90 ° in the direction of rotation, namely, where the rotational speed of the connecting rod much lower and in particular per revolution on lowest is. Since, due to the design, often due to the limited space around or within the crankshaft is not possible to access at those positions during a Pleuelumlaufs on the connecting rod arranged on the switching element, where the Pleuelumlaufgeschwindigkeit in particular is maximum, it must be ensured that a reliable Switching of the switching element reliably takes place even at lower Pleuelumlaufgeschwindigkeiten. This can, as explained above, be carried out by the approach according to the invention, namely namely the slope or the change in the orientation of the contact surface relative to the plane of movement of the switching element in a Pleuelumlauf speed-dependent or depending on the speed change is chosen to be steeply different.

The switching element is, since it is arranged on the connecting rod mainly in the region of the large conrod bearing (crankshaft journal bearing), moved with this. During one revolution of the connecting rod, the switching element moves along an ellipse. Since access should preferably be given to the changeover element when the respective connecting rod section in which the changeover element is arranged is located outside the crankshaft and its balancing weights, only a limited path section is available per circulation for this access. Depending on the engine type (in-line, V or boxer engine), only the areas of an orbit may possibly be close in this respect offer one of the two focal points of the ellipse; In these areas, the rotational speed of the connecting rod and thus of the switching element can be relatively low or the change in the rotational speed can be relatively large. With regard to the choice of the arrangement of the actuating element along the path of movement of the switching element per circulation is on the also filed today at the European Patent Office PCT patent application entitled "positioning of the switching element for a mechanically switched VCR connecting rod" with the lawyer 150821where, the contents of which are hereby incorporated by reference into the subject matter of the present patent application.

In order to provide a reciprocating piston and in particular an internal combustion engine, in which the vibrations are reduced when shifting a switching element of an adjusting mechanism for adjusting the compression ratio of the internal combustion engine, it is proposed according to a variant of the invention that the button of the actuating element at at least two different points of a contact track, along which the switching element moves and contacts the button, each having at least two different slopes with respect to a reference plane, which is perpendicular to the crankshaft axis and z. B. is defined by the plane of movement of the switching element in a circulation of the connecting rod, wherein the two slopes relative to the reference plane have the same sign. The adjusting mechanism for adjusting the variable compression of the internal combustion engine can be realized in particular by an adjustable engine component. An adjustable engine component may be, for example, a variable effective length conrod, a variable compression height piston, or a crankshaft with a variable crank radius. In WO-A-2014/019683 a connecting rod with variable effective length between the crankshaft and the compression piston is described, whereby the compression ratio of the internal combustion engine is adjusted.

The adjustment of this adjustment mechanism by means of a switching element, which is arranged in the lower region of the connecting rod and switches a switch. It is with respect to a possible embodiment of the adjustment mechanism, the particular hydraulically acting switch for switching the adjustment mechanism and an arrangement for switching the switching element fully referenced to the above-mentioned publications, whose contents belong by reference to the subject of the present application.

The first position of the first switching element and thus of the switch corresponds to a first compression ratio of the internal combustion engine, which is via the adjusting mechanism, preferably taking advantage of forces acting on an engine component during operation of the internal combustion engine, after switching the first switching element from the second position to the first Position or vice versa. Similarly, the second position of the first switching element corresponds to a second compression ratio of the internal combustion engine, which is via the adjusting mechanism, again preferably using forces acting on an engine component during operation of the internal combustion engine, after switching the first switching element from the first position to the second Position stops. A first actuating element is preferably arranged in an area which lies outside the space occupied by the crankshaft during its rotation, in particular below the crankshaft. Advantageously, the first actuating element for switching the switching element from the first position to the second position and vice versa has a first and a second button. The first and the second button allow a switching of the first switching element during operation of the internal combustion engine (from the first position to the second position and vice versa). When transferring the first switching element from the first position to the second position, the first switching element abuts the first button of the first actuating element. In an advantageous embodiment of the invention, the first switching element switches over from the first to the second position on contact with the first button of the first actuating element due to the pulse. In a modified embodiment, the first switching element can be switched from the first to the second position by sliding along the first button of the first actuating element. A further development provides that the first switching element at a first speed of the internal combustion engine through

Sliding along and switchable at a second speed by impulse upon contacting the first button of the first actuating element from the first to the second position, wherein the first speed is different from the second speed. Preferably, the first speed is lower than the second speed.

When transferring the first switching element from the second position to the first position, the first switching element abuts the second button of the first actuating element. In an advantageous embodiment of the invention, the first switching element switches on the basis of the pulse, it can be switched from the second to the first position when contacting the second button of the first actuating element. In a modified embodiment, the first switching element is switchable by sliding along the second button of the first actuating element from the second to the first position. A further development provides that the first switching element at a first speed of the internal combustion engine by sliding along and at a second speed by pulse when contacting the second button of the first actuating element from the second to the first position is switchable, wherein the first speed of the second speed is different. Preferably, the first speed is lower than the second speed. The first switching element can be designed as a pin, cylindrical pin or bolt which protrudes from the connecting rod. Preferably, the first switching element has two rounded ends, which touch the first button or the second button for switching. The movement of the first switching element is dependent on the kinematics of the internal combustion engine, which is determined by the crank radius and the push rod length or the push rod ratio, and the position of the first switching element, where the switching element is located on the connecting rod.

The reference plane is to be understood as a plane against which the two different gradients of the first and the second button can be determined. The reference plane may be, for example, the plane which passes through the center of gravity of the crankshaft and to which the crankshaft axis is perpendicular. However, the reference plane may also be that plane within which the switching element moves during one revolution of the connecting rod. A first slope at a first point of the first button may be formed over an intersection angle between a surface normal of the reference plane and a first surface normal of the first button passing through the first point. A second slope with respect to the reference plane can accordingly be formed at a second point of the first button over an intersection angle between the normal of the reference plane and a second surface normal of the first button which extends through the second point.

The surface normal of the reference plane and in each case the first and the second surface normal are the same orientation in space. A similar orientation here means that a scalar product of the surface normal of the reference plane with each of the first or second surface normal is positive.

The first actuating element is preferably parallel to the orientation of the Kur- belwellenach.se linearly displaceable between a first and a second actuating position. In the first actuating position of the first actuating element, the first switching element can be switched from the first position to the second position by means of the first button. In the second actuating position of the first actuating element, the first switching element can be switched from the second position to the first position by means of the second button.

The first switching element is preferably fixed relative to the connecting rod by means of a latching element in two latching positions, which respectively correspond to the first and the second position of the first switching element. When hitting the first switching element to z. B. the first button of the first actuating element, the switching element is moved from the first detent position to the second detent position. After impact, preferably after "leaving" the first button, the switching element remains in the second detent position. In an adjustment from the second position to the first position, the switching element meets the second button of the first actuating element and is moved from the second detent position to the first detent position. After the switching element has moved past the second button of the first actuating element, it remains in the first detent position. The configuration of the latching element can in particular bring about a displacement path of the first switchover element into a first or second latching position, which is a distance of the first switchover element in the first and second latching position corresponding to the second or first button, preferably from about 1 mm to 2 mm, realized.

In the first switching position, the switching element projects beyond a first side of the connecting rod, while in its second switching position it projects beyond a second side facing away from the first side of the connecting rod. If the switching element as a bolt or the like. is formed, this bolt is z. B. in a connecting rod or the bore odgl. Recess. The embodiment described above assumes that the switching element after completion of the operation by the actuating element occupies a different switching position than before. But it is also conceivable that the switching element automatically returns to the other switching position after an operation in which it has been briefly transferred to the one switching position (similar to a toggle switch). In such an embodiment, the actuating element thus needs to be equipped with only one button. Due to the kinematic conditions of the crank mechanism of the internal combustion engine, which is predetermined primarily by the crank radius, the push rod length, the piston stroke and the push rod ratio, describes the switching element, which is arranged on the connecting rod, an elliptical movement and has a non-uniform velocity. The position of the connecting rod is described below with the indication of degrees crank angle, wherein a crank angle of 0 degrees describes the position of the connecting rod in its top dead center and a crank angle of 180 degrees, the position of the connecting rod in its bottom dead center. The elliptical movement of the connecting rod results in a different speed, in particular absolute speed of the switching element as a function of the position of the connecting rod.

The following is an embodiment of the invention is considered in which the actuating element is switched from the first operating position to the second operating position within a time interval which lasts longer than the time period for at least one complete revolution of the first connecting rod. Furthermore, in this embodiment, the actuation of the first actuating element is not synchronized with a specific position of the connecting rod. This can cause the impact point of the switching element on the first button or the second button of the first actuating element is unpredictable. Compared to the prior art with a flat first button with the same slope in all their points an actuator with a first button, which at least at two different points each have a different slope from the reference plane, reduce the vibration when switching the switching element. The switching element hits at different points of the first and second button, depending on the position occupied by the actuating element at the time of impact of the switching element.

Particularly advantageously, the slope of the first or second button is adapted to the course of the movement speed of the first connecting rod, or of the switching element arranged thereon during the circulation of the connecting rod. Depending on the movement position of the first operating element when moving, for example, from the first operating position to the second operating position, the first button intersects the path of the first switching element at different points when the first switching element is in the first position. Depending on where the first actuating element is located when the first switching element encounters the first button, the switching element strikes the first button at a different impact point. A connecting line of all possible points of impact of the first switching element on the first button results in a switching curve arranged in space when the first switching element is in the first position.

The slope of the first button relative to the reference plane is matched to the course of the movement speed of the first switching element such that the first button at a first impact point at which the first switching element has a first speed, a first

Slope against the reference plane, and the first button at a second point of impact, wherein the first switching element a second speed, which is higher than the first speed, has a second slope relative to the reference plane, wherein the first slope is greater than the second slope. This means that in this embodiment the rise of the button is greater, the lower the speed of the switching element with which the switching element passes the respective area of the button.

Preferably, the slope of the second button of the first actuating element is adapted to the speed characteristic of the first switching element in a simple manner.

In a further embodiment of the subject invention is provided that the button has a curvature. In this embodiment, t he jeweil strength of impact of the switching element preferably lie on the ERS th and second button on a connecting line, d ie is continuous in the mathematical ^¬'s sense.

In a further embodiment of the subject invention, it can be provided that the first and the second button are formed as planes arranged next to one another, each with different pitches relative to the reference plane. The first or second button can be formed, for example, by a sheet bent several times.

In a further development of the subject matter of the invention, it is provided that the curvature varies along a path of the switching element. Example ^¬ can as d ie curvature be higher in a place nied engined absol uter Bewegungsgeschwind ig ness of the switching element on the railway line of the switching element than a location at which the switching element has a higher absol ute Geschwind ig ness.

In a further development, it is provided that the button is concave in an area. In a further embodiment, it is provided that the button surface is convex in one area.

A further advantageous embodiment of the invention provides that the internal combustion engine has a second connecting rod and a second actuating element, wherein the first actuation element has a concave button and the second U mschalter a convex button. Particularly advantageous ^¬ way, the first actuator a first concave button and a second concave button for switching the switching element of the first connecting rod of the first actuator ung in t he second adjusting clothes or from the two-th manipulated ung in t he first Stel lung While the second actuator has a first convex button and a second convex button for switching the (second) switching element of the second connecting rod from the first Stel development in the second Stel development or from the second Stell ung the second switching element in the first Stel development ,

In a further image UNG can be provided that t he internal combustion engine having a first and a second Zyl inthe bank and Minim ^¬ least one actuating element is provided with button per bank. For example, it may be provided that a first, third and fifth actuating element are provided, each with concave first and second buttons for the first bank and a second, fourth and sixth actuating element, each with convex first and second buttons for the second cylinder bank. Preferably, the first actuating element (particularly preferably also the third and fifth actuating element) is or are arranged in a range of 200 degrees to 250 degrees crank angle. Furthermore, it can be provided that the second, preferably also the fourth and sixth actuator in a range of 110 degrees to 160 degrees crank angle angeord net is / are.

In a further embodiment, it is provided that the first actuating element has a second surface which has a slope with a sign opposite to the slope of the first and / or second button and adjacent to the first or second button, and as a fuse against a shearing of the switching element at a turning back of the internal combustion engine acts.

In a further embodiment of the invention it can be provided that the first or second button in a direction opposite to the top dead center of the connecting rod and / or in a direction opposite thereto, has a varying pitch with respect to the reference plane.

Furthermore, a method for switching an adjustable compression ratio of an internal combustion engine with a crankshaft, a first connecting rod, a first actuator with a button, a second connecting rod, a second actuator with a button and an adjustment mechanism for adjusting the variable compression ratio is proposed, wherein a switching element for switching the adjusting mechanism is arranged on the first connecting rod and on the second connecting rod and the method comprises the following steps. In a first step, the first actuating element and the second actuating element are moved from a first to a second or from a second to a first actuating position. This is preferably done independently of a rotational position of the crankshaft and thus not in synchronism with the crankshaft rotation. In a second step, the first connecting rod is moved in the direction of rotation until the switching element of the first connecting rod at a first

Touching touches the button of the first actuating element, wherein the button at the first point of contact has a first slope relative to a reference plane, which is described by a line of the first connecting rod. At the same time the second connecting rod is moved in the direction of rotation until the switching element of the second connecting rod at a first

Touching touches the button of the second actuating element, wherein the button at the first point of contact has a second slope relative to the reference plane, wherein the two slopes are different and opposite the reference plane have the same sign. Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and with reference to the figures.

These show in

Fig. 1 is a sectional view of an internal combustion engine with an adjustable compression ratio, a crankshaft, a first connecting rod, an adjustment mechanism for adjusting the compression ratio and a first switching element.

Fig. 2: a sectional view of the first switching element with associated

Switch installed in the connecting rod;

Fig. 3 shows a speed profile of the first switching element over a first crankshaft range;

Fig. 4 shows a second speed profile of the first switching element over a second crankshaft range;

5 shows a sectional view of a first connecting rod and a second connecting rod and a respective speed profile of a first and a second switching element in the region of a first and a second actuating element;

Fig. 6 is a sectional view of the first actuating element and

Fig. 7 is a sectional view of a second actuating element.

1 shows an internal combustion engine having a housing 1 with a variably adjustable compression ratio, a crankshaft 2 at least one connecting rod 3, an adjusting mechanism 4 for adjusting the adjustable Compression ratio and a first switching element 5 for a switch (not shown in Fig. 1, see, for example, Fig. 2) for switching the adjusting mechanism 4. The first switching element 5 is angeord ^¬ net on the connecting rod 3. The connecting rod 3 has a connecting rod shank on which the connecting piston 3 'bearing connecting rod eye is formed, and a connecting rod cap 3, which surrounds the crankshaft journal. Furthermore, a holder 6 is preferably provided in an area near the bottom dead center of the connecting rod 3, which is movable back and forth parallel to the crankshaft center axis extension and on which an actuating element 7 with two actuating surfaces 8, 8 'for optional mechanical action on the first switching element. 5 are arranged during the passing movement of the actuating element 7 during one revolution of the connecting rod 3. The actuating surfaces 8, 8 'cause a switching of the first switching element 5 and thus the switch from the first in the second switching position, while the actuating surface 8', the first switching element 5 is actuated for transferring the switch from the second in the first switching position.

The first switching element 5 may, in a specific embodiment, a switch 20 in the form of a hydraulic directional control valve for a hydraulic control of a working space, as for example in Fig. 1 of DE-A-10 2005 055 199 designed as a working space 29.1 and 29.2, respectively ^¬ control. In particular, the first switching element 5 can control a hydraulic directional control valve, which in each case releases a drainage bore assigned to a working space. Such a drainage hole is shown for example in FIG. 2 of DE-A-10 2005 055 199 as drainage bore 36. The hydraulic valve has at least two switching controls, which correspond in each case to a first position of the switch 20 and a second position of the switch 20. DE-A-10 2012 020 999 describes different possibilities of interconnecting a hydraulic directional control valve. With regard to a possible embodiment of the hydraulic circuit in the connecting rod, as well as the design of the circuit in the connecting rod, this document makes full reference in the context of the disclosure of this present application. sen, so that the content of DE-A-10 2012 020 999 belongs to the subject of the present application.

Fig. 2 further shows the interaction of the first switching element 5 with a hydraulic directional control valve as a three / two-way valve 11 or generally with the switch 20. The three / two-way valve function is in this case by the interaction of a first two / two-way valve 12 and a second Two / two-way valve 13 realized. The two / two-way valves 12 and 13 can be designed as poppet valves, for example by a ball check valve, which can be pressed on a plunger. A first plunger 14 is associated with the first two / two-way valve 12. Furthermore, a second plunger 15 is associated with the second two / two-way valve. The two plungers 14 and 15 are controlled by the first switching element 5. The first switching element 5 can be held by means of a latching device 16 in a specific switching position. The latching device 16 can be realized via a resilient pressure piece 17 and a first latching contour 18 formed on the first switching element 5. So that the tappets do not unintentionally open the two / two-way valves under the influence of inertial forces, the tappets are pressed against the first changeover element 5 by springs. In addition to the first latching contour 18, the latching device 16 has a second latching contour 19. The locking contour 18 causes, in cooperation with the resilient pressure piece 17 holding the first switching element 5 in a first position. The latching contour 19, in cooperation with the resilient pressure piece 17, causes the first switchover element 5 to be held in a second position. By displacement of the actuating element 7 in one of the two by the double arrow in FIG. 2 indicated directions, the switching element 5 and thus the switch 20 when the connecting rod 30 with its switching element 5 having connecting rod portion on the actuating element 7 moves past (see the individual case in Fig. 2) transferred from a first switching position to a second and vice versa.

The first switching element 5 moves during one revolution of the connecting rod 3 Because of the kinematic specifications, such as the crankshaft radius, the push rod length of the connecting rod 3 and the position of the first U mschalt ^¬ elements 5 on the first connecting rod 3 along a movement path with varying speed. In Fig. 1 is shown for a special le design an elliptic see line 9 of the first switching element 5. At a virtually constant speed of the internal combustion engine, this results in a Geschwind igkeitsverlauf, which varies depending on the position of the first Umschaltele ^¬ element 5. In the following, the positions of the first switching element 5 on the web 9 will be indicated in degrees of crank angle as a function of the rotational position of the crankshaft 2, which is described by an angle alpha. In this case, a value of the angle α pha of 0 degrees crank angle corresponds to a position of the first switching element 5 at the top dead center of the first connecting rod 3, this point in FIG. 1 on the Bahnl inie with a point 10 is located. A value of the angle alpha degree crank angle of 180 corresponds to the position 21 of the first switching element 5 which lies on the line 9.

Fig. FIG. 3 shows a first qualitative velocity curve 41 of the absolute velocity vi of the first switching element 5 over the angle alpha in degrees of crank angle. The absolute speed of the first change-over element 5 is strictly monotonically increasing in a crank angle range of 170 degrees to 190 degrees. At a speed of the internal combustion engine of about 4500 revolutions per minute, the absolute speed of the switching element preferably reaches a value of a maximum of 30 m / s.

Fig. 4 shows a second qualitative Geschwind ig keitsverlauf 42 of the absolute velocity v2 of the first switching element 5 to the position of the first switching element 5, in degrees crank angle of the angle al ^¬ pha. In a crank angle range of 200 degrees to 220 degrees, the absolute speed of the first switching element 5 is strictly monotonically decreasing. At a speed of the internal combustion engine of about 4500 U m ^¬ d rehungen per minute reaches the absolute speed of U mschaltele- It prefers a maximum value of 30 m / s.

Fig. 5 shows the crankshaft 2, the first connecting rod 3 and a second connecting rod 51 and a Massenausg easy element 52. Furthermore, a speed curve 53 of the first switching element 5 of the first connecting rod 3 and a speed ^¬ course 54 of a first switching element of the second connecting rod 51 is ^¬ recorded , In this case, the individual NEN marked points of the speed curve 53 d he positions of the first switching element 5 of the first connecting rod 3, wherein from one position, for example, the position 55, to the next position, for example, the position 56, the crankshaft 2 to 5 Degree crank angle d reht. Accordingly, a large distance between two points represents a high absolute velocity of the first switching element 5, while a small distance between two points, for example between the point 57 and the point 58, is a low absolute velocity of the first switching element 5 represents. The movement direction of the first connecting rod 3 with the arrow 59 dargestel lt. Adapted to the speed profile of the absolute speed of the first switching element 5 is a first button 60 and a second button 61 of the first Actu ^¬ gungsungselement 7 is formed. The view A on the first actuator 7 is d urch by looking at the plane 62 in the direction 63 made light.

By way of example, the respective gradients of the various impact points will be illustrated below. At the in Fig. 3, the first switching element 5 has a first speed and a second speed at a corresponding point of impact 57. The point belonging to Bahnl inie dot 64 corresponds to the impact point 75 in FIG. 6 and the corresponding point 57 of the web line 59 corresponds to the impact point 76 on the first button 71 of the first actuating element 7.

The rise of the first button 71 at the point of impact 75 is with the Line 77 does not clarify. The rise of the first button 71 relative to the reference plane 73 at the impact point 76 is shown by the line 78. For better illustration, the two lines 77 and 78 are displaced in parallel in the direction 74 towards the reference plane 73 and represented by the respective lines 79 and 80. The jeweil strength gradients at the impact points 75 and 76 can each have a first surface normal 81 to the reference ^¬ plane 73, describe a normal 82 to the line 79, a second surface normal 83 to the reference plane 73 and a normal 84 to the line 80th The slope at the impact point 75 is equal to the value of the tangent of the angle a, which is described between the first surface normal 81 of the reference plane 73 and the normal 82 to the line 79. The gradient at the impact point 76 of the first button 71 is d urch the tangent of the angle ß described, wherein the angle ß by the angle between the second surface normal 83 to the reference plane 73 and the normal 84 to the line 80 ge ^¬ forms is.

The absolute Geschwind ig ness of the first switching element 5 is higher than the absolute Geschwind ig ness of the first Schaltelemen- to the up ^¬ treffpunkt 75 tes 5 at the impact point 76. The first button 71 of the first Betätig ungselements 7 is such to this Geschwind adapted igkeitsverlauf that the riser ung at the hit point 75 is smaller than the slope at the point of impingement 76. In advantageous legally t he first button 71 is designed as a kon ^¬ kave button.

Fig. 7 shows a further embodiment of the first actuating element 7 with a first button 91 and a second button 92, wherein the first button 91 is defined by a first plane 93, a second plane 94 and a ^third plane 95, each at different angles n 96, 97 and 98 extend to the reference plane 99, is formed. The angles 96, 97 and 98 of the planes 93, 94 and 95 are dependent on the speed of the switching element 5, which this in his movement along the single nen levels chosen, and that the angles are greater, the smaller the speed of the switching element 5 is.

Fig. 8 shows the second actuating element 7, which is arranged in a crank angle range of approximately 120 degrees to 170 degrees. Fig. 8 shows a

Top view of the second actuating element 7 from the direction 66 of FIG. 3. The second actuating element 7 has a first button 102 and a second button 103, wherein the first button 102 and the second button 103 are adapted to a speed curve 54 of a second switching element 5 of the second connecting rod 51. The second switching element 5 has, at a point of impact 167, a first speed and at a point of impact 156, a second Geschwind ig ness on, the second Ge ^¬ dwindling ness strength is higher than t he first Geschwind ig ness. According to the invention, the rise of the first button 102 at the impact point 167 is higher than the rise of the first button 102 at the impact point 156. The tangent 104 of the first button 102 contacting the impact point 167 describes a reference plane 105 which is perpendicular to the crankshaft axis of Kurbelwel le 2, an angle 106. The tangent 107 of the first button 102, which touches the impact point 156, forms with the reference plane 105 an angle 108th

The course of the first button 102 of the second actuating element 7 is adapted to the speed of the second switching element when hitting the first button 102 such that the angle 106 and thus the rise at the point of impact 167 at the first speed ness of the second switching element is higher than the angle 108 and th e pitch of the first button 102 at the point of incidence 156, wherein t he velocity of the second U is mschaltelements 5 is higher at the impingement point 156 than the vELOCITY ^¬ ness of the second switching element 5 at the impact point 167 ,

Preferably, the first connecting rod 3 of a first bank of an internal combustion engine and the second connecting rod 51 of a second bank of the combustion engine assigned machine. The in Fig. 3 illustrated embodiment accordingly has banking-adapted actuators. Preferably, for each individual connecting rod, for example for a first, second, third, fourth, fifth and sixth connecting rod, in each case a single actuating element 7 before. The individual actuators 7 can be moved in opposite directions or in the same direction. In the same direction displacement of the actuators 7, the individual banks each have different connecting rods, wherein the respective switching elements 5 of the single connecting rod each point to one end of the crankshaft and the other opposite end of the crankshaft. The internal combustion engine may be an in-line engine, a V-type engine or a boxer engine. Preferably, in an inline engine, the first and the second actuating element 7 may not be arranged centrally, that is to say not underneath the crankshaft 2, opposite the bottom dead center of the connecting rod, but laterally thereof, as shown in FIG. 3 shown.

The in Figs. FIGS. 6 to 8 show profiles of the first and second buttons, each representing a shock-optimized spatial contact curve, on which the first or second switching element 5 contacts the first or second button of the first and second actuating element 7 when actuated. This preferably spatial, optimized Berührkurve allows a comparatively gentle power surge when switching and reduces the wear of the switching elements 5, the / the actuating elements 7 and the components within the connecting rod. Likewise, by an arrangement of the actuating element 7 laterally of the bottom dead center of the connecting rod to release an additional space in the region of the bottom dead center of the connecting rod and thus reduce the overall height of the internal combustion engine. Furthermore, a steeper Berührkurve the first and second buttons of the respective actuating element 7 is made possible by such a lateral arrangement. In this case, the actuating element 7 is preferably arranged directly below the connecting rod.

To illustrate the buttons of the actuators of FIGS. 6 to 8 be said that the actuation elements 7 each have additional switching ^¬ surfaces 43, ie he thought to reindeer at a reverse twist of the connecting rod, as for example when switching off the engine or when back ^¬ rol len of a vehicle with engaged reverse gear of Case may be to protect the U mschaltelement against damage by, for example, shearing, if during this back twisting of the connecting rod zufäl lly the actuating element 7 is moved with one of its buttons in the direction of the movement path of the switching element 5. The invent ung can alternatively d urch rewrite a of the following feature groups further, the feature groups are combined with one another and individual features of one Merkmalsg ru p ^¬ pe with one or more features of one or more other feature groups and / or one or more of previously mentioned embodiments of the invention can be combined.

1. Internal combustion engine with an adjustable compression ratio, a crankshaft 2, at least one (first) connecting rod 3, an adjustment mechanism 4 for adjusting and / or triggering an adjustment and / or an optional self-actuating adjustment or adjustment of the SET lbaren Dilute ichtungsverhältnisses, a (first) switching element 5 for switching of the adjusting mechanism 4, wherein the (first) switching is ^¬ is 5 to the (first) connecting rod 3 ord net, and a (first) actuator 7 with at least one ( first) switching or Betätig ungsfläche to the OB berführen the (first) switching element 5 from at least one of a first Dilute I ^¬ duty ratio corresponding first Stel lung in a second Dilute ichtungsverhältnis corresponding second Stel lung and / or vice versa, wherein the control area on at least two differed union points two differnet cozy inclines relative to a Refe ^¬ renz- b zw. Radial plane has, which is perpendicular to the crankshaft axis and in which the switching element in a revolution of the Pleuels moves, with the two slopes with respect to the reference plane have the same sign. Internal combustion engine according to item 1, wherein the button has a curvature. Internal combustion engine according to item 1 or 2, wherein the degree of curvature varies along a line of the (first) switching element 5 on the button. Internal combustion engine according to one of the preceding figures, wherein the button is concave in a region. Internal combustion engine according to one of the preceding figures, wherein the button in a region is convex. Internal combustion engine according to one of the preceding figures, wherein the internal combustion engine has a second connecting rod and a second actuating element, wherein the first actuating element has a concave button and the second actuating element has a convex button. Internal combustion engine according to one of the preceding figures, wherein the internal combustion engine has a first and a second cylinder bank and per cylinder bank at least one actuating element is provided. Internal combustion engine according to one of the preceding figures, wherein the (first) actuating element has a further button, which has a gradient with opposite sign to the slope of the first button and as a safeguard against a shearing off of the (first) switching element when turning back the combustion combustion engine acts.

Internal combustion engine according to one of the preceding figures, wherein in the (first) actuator is arranged in a range of 200 to 250 degrees crank angle.

Internal combustion engine according to one of the preceding figures, wherein the (first) actuating element is arranged in a range of 110 to 160 degrees crank angle.

Internal combustion engine according to one of the numbers, wherein the (first) actuating element for acting on the first switching element is displaceable at least parallel to the crankshaft axis.

A method for switching an adjustable compression ratio of an internal combustion engine with a crankshaft 2, a first connecting rod 3, a (first) actuator with a button, a second connecting rod, a second actuator with a button and a verse tell mechanism for optionally active and / or automatic understanding of the compression ratio, wherein a first switching element 5 and a second switching element for switching the adjusting mechanism are arranged on the first connecting rod 3 and on the second connecting rod, respectively, with the following steps: a) moving the first actuating element 7 and the second actuating element from a first to a second or from a second to a first Betätigungselmentposition, preferably independently of one of the current rotational position of the crankshaft 2; b) circulating the first connecting rod 3 until the first switching element ment the first connecting rod touches the button of the first actuating element 7 at a first contact point, wherein the button at the first contact point has a first slope with respect to a plane which is described by a line of the first connecting rod or the first switching element 5 of the first connecting rod ;

Circulating the second connecting rod until the second switching element of the second connecting rod touches the button of the second actuating element 7 at a first contact point, wherein the button has a second slope with respect to the plane at the first contact point, wherein the two slopes are different and opposite to the plane each have the same sign.

E N G L I S H E S T E

1 housing

1 'cylinder

2 crankshaft

3 connecting rods

3 'compression piston

4 adjustment mechanism

5 switching element

6 bracket

7 actuator

8 actuating surface

8 'actuating surface

9 railway line

10 point

11 three / two-way valve

12 two / two-way valve

13 two / two-way valve

14 pestles

15 pestles

16 locking device

17 pressure piece

18 locking contour

19 locking contour

21 position

29 workspace

36 drainage hole

41 speed course

42 speed history

43 further actuating surface

51 connecting rods

52 mass balance element

53 Speed course

54 speed history

55 position

56 position

57 impact point

58 point

59 railway line

60 button

61 button

62 level

63 Viewing direction

64 impact point

66 direction

71 button

72 button

73 Reference level

74 direction 75 impact point

76 impact point

77 line

78 line

79 line

80 line

81 surface normals

82 normal

83 surface normals

84 normals

91 button

92 button

93 level

94 level

95 level

96 angles

97 angles

98 angles

99 reference level

102 button

103 button

104 tangent

105 reference plane

106 angles

107 tangent

108 angles

156 impact point

167 impact point

Claims

1. Reciprocating piston engine, in particular internal combustion engine, with variable compression ratio, with

a housing (1),

a housing (1) rotatably mounted crankshaft (2) with a crankshaft center axis,

a connecting rod (3) which is rotatably mounted on the crankshaft, a compression piston (3 ') carried by the connecting rod (3), which is bidirectionally movably guided within a cylinder (1') formed in the housing (1),

an adjustment mechanism (4) arranged on the connecting rod (3) for adjusting the compression ratio by selectively releasing and / or blocking and / or supporting a displacement of the compression piston (3 ') relative to the connecting rod (3),

arranged on and / or in the connecting rod (3) switch (20) with a mechanically operated switching element (5) for transferring the switch from a first switching position corresponding to a first compression ratio, in at least a second switching position, the one of the first compression ratio corresponds to different second compression ratio, and vice versa,

wherein the switching element moves during one revolution of the connecting rod (3) in a plane of movement which extends at right angles to the crankshaft center axis, and

an actuating element (7) for the mechanical actuation of the switching element (5),

wherein the actuating element (7) has at least one actuating surface (8, 8 '),

wherein the actuating element (7) for actuating the switching element (5) is movable in the direction of the movement plane and thereby the actuating surface (8, 8 ') in contact with the at Circulation of the connecting rod (3) passing switching element (5) can be brought and

wherein the actuating surface (8, 8 ') along a contact track with the passing switching element (5), viewed at at least two locations, relative to the plane of movement of the switching element (5) has a different pitch, each having the same sign.

2. A reciprocating engine according to claim 1, characterized in that the contact track has at least two straight sections of different pitch, each having the same sign.

3. Reciprocating piston engine according to claim 1, characterized in that the contact track has a curvature extending in the same direction.

4. Reciprocating piston engine according to claim 3, characterized in that the contact track is curved convexly or concavely.

5. Reciprocating piston engine according to one of claims 1 to 4, characterized in that the actuating element (7) has a further actuating surface (8, 8 '), wherein both actuating surfaces (8, 8') facing each other and on both sides of the movement path of the switching element (5 ) are arranged and formed at least in terms of their Umschaltelement- contact tracks substantially symmetrically to the plane of movement of the switching element (5).

6. A reciprocating engine according to one of claims 1 to 5, characterized in that on the crankshaft (2) at least one further connecting rod (3) with a switch (20) with switching element (5) for adjusting the compression ratio is rotatably mounted, that the switching element (5) the further connecting rod (3) a further actuating element (7) is associated with at least one actuating surface (8, 8 ') for the mechanical actuation of the switching element (5) of the further connecting rod (3).

7. A reciprocating piston engine according to claim 6, characterized in that the at least one actuating surface (8, 8 ') of each actuating element (7) have an opposite direction at least along their respective contact tracks.

8. Reciprocating piston engine according to one of claims 1 to 7, characterized in that the or each actuating element (7) in addition to the at least one actuating surface (8, 8 ') arranged additional actuating surface (43), these two actuating surfaces (8, 8 ', 43) of the actuating element (7) or of each actuating element (7) are arranged on the same side of the plane of movement of the associated switching element (5), and that the respective additional actuating surface (43) has a pitch for the respective other actuating surface (8, 8 ') has an inverse slope and the prevention of damage to the switching element (5) in an unintentional circulation of the connecting rod (3) in the direction opposite to its preferential circulation direction is used.

9. Reciprocating piston engine according to one of claims 1 to 8, characterized in that the or each actuating element (7) is movable back and forth in a direction parallel to the crankshaft center axis direction.