EP2500533A2 - Combustion engine with mixed cam shaft - Google Patents

Abstract

The engine has working cylinder with two intake valves (78) and exhaust valve (80). The valve timing of mixed camshaft (18) associated with intake and exhaust valves relative to the valve timing of other cam is adjusted in early or later stages. A cam carrier (54) is arranged axially displaceable on the joint camshaft. The different cam paths (60,62,64,66) are formed on cam carrier for cams (24,26). The grooves (56,58), driving pin (92) and cam pin (96) are provided between first and second axial positions, for axial displacement of cam carrier with respect to mixed camshaft.

Description

The invention relates to an internal combustion engine, in particular a diesel engine, in particular a motor vehicle, with at least one working cylinder, wherein each cylinder at least two intake valves and at least one exhaust valve is assigned, wherein at least two camshafts are provided, of which at least one mixed camshaft both at least one inlet valve and actuated at least one exhaust valve, wherein at least one mixed camshaft which actuates both at least one inlet valve and at least one exhaust valve, a phaser is arranged which valve timing of the mixed camshaft associated intake and exhaust valves against the valve timing of the at least one other camshaft optional after Early or late adjusted, according to the preamble of claim 1.

From the DE 44 26 557 A1 It is known, working cylinders of an internal combustion engine functionally identical valves, so for example, two intake valves or two exhaust valves to arrange diagonally opposite, so that two camshafts each control a portion of the intake valves. In this way, two separate inlet systems are provided, which have different timing, but these timing are fixed.

In the well-known Miller / Atkinson cycle, the point in time "intake valve closes" (ES) is postponed. In this way, already in-cylinder fresh gas is z.T. pushed out again. This means a filling disadvantage, which can be compensated but via a charge with a suitable boost pressure. In this case, the charge pressure in the volume between the loader outlet and the engine inlet is to be controlled so that the boost pressure at each Miller operating point, i. each operating point in which the "MillerCycle" is used, corresponds to the theoretical compression end pressure in the working cylinders of the internal combustion engine at the time intake valve closes. For the control, optionally also control, come pressure and / or temperature and / or mass flow sensors or useful combination sensors of the three types of sensor used.

The positive effect of the Miller / Atkinson cycle on the NO _x emission and homogenization of the diesel mixture by means of an early or late point in time for closing the inlet valve is known. Furthermore, in ottomotorischen applications Tapping tendency when charging high can be significantly reduced. In contrast to the gasoline engine, which can work due to lack of geometric constraints with positive valve overlap, in the diesel engine, a simple implementation of the method using a phaser is generally not possible. The reason for this is a mechanical collision of the valve with the piston during early adjustment and increased pumping work with retardation.

From the pamphlets DE 42 30 877 and DE 199 08286 a valve train is known in which a cam carrier is arranged rotationally fixed and axially displaceable on a base camshaft. The cam carrier consists of a tubular material, on which at least one cam is arranged, in which emerge from a common base circle axially offset several different cam tracks. By the axial displacement of the cam piece on the base camshaft, a gas exchange valve can be actuated by the differently shaped cam tracks in different ways, with the cam tracks differ in the Hubkontur and / or in the phase position.

The object of the invention is to improve or optimize intake and / or exhaust gate times for the thermodynamic optimization of engine operation in the map.

This object is achieved by an internal combustion engine o.g. Art solved with the features characterized in claim 1. Advantageous embodiments of the invention are described in the further claims.

For this it is in an internal combustion engine o.g. Art provided according to the invention that at least on the mixed camshaft at least one cam carrier is provided, wherein the cam carrier relative to this mixed camshaft rotatably and axially displaceably on the mixed camshaft is arranged, wherein the at least one cam carrier has at least one cam on which at least two different Cam tracks are formed, wherein means for axially displacing the at least one cam carrier relative to the mixed camshaft between a first axial position and at least one second axial position are provided.

The at least two different cam tracks may be arranged axially spaced from each other and extend substantially parallel to each other. In particular, at least a first of the at least two different cam tracks may have a different course from a second of the at least two different cam tracks on the cam at a radial distance from the axis of the cam Have camshaft and / or in the circumferential direction of the mixed camshaft.

This has the advantage that a cam switch with a reduced number of cam positions is available, since, for example, an actuator converts both an intake cam and an exhaust cam.

A high mechanical stability with functional reliability of the cam carrier over many cycles is achieved by enclosing the at least one cam carrier for supporting the at least one camshaft of at least one cylinder head-fixed camshaft bearing.

In embodiments in which the internal combustion engine has a plurality of working cylinders, the mixed camshaft may in each case comprise at least one cam for one of the working cylinders, wherein the intake and exhaust valves associated with the mixed camshaft are simultaneously adjustable by actuation of the adjuster either early or late.

A particularly well optimizable adaptation of valve timing to an operating state of the internal combustion engine is achieved in that the adjuster is designed such that it has an adjustment range for the valve timing of 60 ° CA +/- 20 °.

The operation of the individual intake and exhaust valves, in particular for a working cylinder, can be designed individually: at least one of the at least two different cam tracks on a cam for actuating an intake valve and at least one other of the at least two different cam tracks on a cam for actuating an exhaust valve different courses at a radial distance from the axis of the mixed. Have camshaft and / or in the circumferential direction of the mixed camshaft. In other words, the cam tracks may have different profiles of their height as a function of the azimuthal angle to the axis of the mixed camshaft.

Furthermore or alternatively, the actuation of the individual intake and exhaust valves of an internal combustion engine with a plurality of working cylinders can be designed individually for individual working cylinders, in particular for the intake valves or for the exhaust valves: at least one of the at least two different cam tracks on one first cam for actuating an inlet or an outlet valve of a first working cylinder and at least one other of the at least two different cam tracks on a cam for actuating a on or Exhaust valve of a second working cylinder may have different courses at a radial distance from the axis of the mixed camshaft and / or in the circumferential direction of the mixed camshaft. In other words, the cam tracks may have different profiles of their height as a function of the azimuthal angle to the axis of the mixed camshaft.

A particularly good and optimized gas exchange during operation of the internal combustion engine is achieved in that each cylinder two exhaust valves are assigned, wherein two camshafts are provided, wherein a first camshaft, one half of the intake and exhaust valves and a second camshaft, the other half of the Ein - And exhaust valves actuated, wherein the first camshaft fixed timing for the camshaft associated valves and is arranged on the second camshaft of the adjuster.

A particularly large adjustment range, especially in diesel engines, without collision between valves and reciprocating piston is achieved in that the second camshaft is designed such that at an adjustment angle of 0 ° KW, the second camshaft associated exhaust valves close earlier than those associated with the first camshaft Open exhaust valves and the intake valves associated with the second cam later and later close than the intake valves associated with the first camshaft.

A further improvement of the thermodynamic optimization of the operation of the internal combustion engine is achieved in that the second camshaft is designed such that close at an adjustment angle of 0 ° KW, the intake valves associated with the second camshaft at the same time with the intake valves associated with the first camshaft. In this case, only a late adjustment takes place.

A particularly simple and functionally reliable axial displacement of the cam carrier is achieved in that the means for axially displacing the at least one cam carrier relative to the mixed camshaft between a first axial position and at least a second axial position at least one axially fixed relative to the blended camshaft and radially between a first and a second pin position displaceable bolt which engages in the second pin position in a formed on the cam carrier, in the radial direction circumferential groove and spaced in the first pin position of this groove, wherein the groove is formed such that the cam carrier of an axial position on the mixed camshaft shifts to a different axial position on the mixed cam shaft when the bolt engages in the groove.

A particularly fast and repeatable axial displacement of the cam carrier is achieved by providing at least one first pin which selectively engages a first groove and at least one second pin spaced axially with respect to the mixed cam shaft from the first pin engages the second groove spaced axially from the first groove with respect to the blended camshaft, wherein the cam carrier moves from the first axial position on the blended camshaft to the second axial position on the blended camshaft as the first bolt engages and disengages the first cam groove second axial position on the blended camshaft moves to the first axial position on the blended camshaft when the second bolt engages the second groove.

The internal combustion engine may in particular be a diesel engine. It is preferably an internal combustion engine of a motor vehicle, in particular a trackless agricultural vehicle.

Fig. 1

eine bevorzugte Ausführungsform einer erfindungsgemäßen Brennkraftmaschine in schematischer Ansicht,

Fig. 2

eine schematische Darstellung der Nockenwellenanordnung bei der erfindungsgemäßen Brennkraftmaschine gemäß Fig. 1,

Fig. 3

eine graphische Darstellung der Ventilbewegung von Einlass- und Auslassventilen der verschiedenen Nockenwellen und der Kolbenbewegung bei einem Verstellwinkel von 0°KW,

Fig. 4

eine graphische Darstellung der Ventilbewegung von Einlass- und Auslassventilen der verschiedenen Nockenwellen und der Kolbenbewegung bei maximaler Verstellung in Richtung Spät und

Fig. 5

eine graphische Darstellung der Ventilbewegung von Einlass- und Auslassventilen der verschiedenen Nockenwellen und der Kolbenbewegung bei maximaler Verstellung in Richtung Früh.

The invention will be explained in more detail below with reference to the drawing. This shows in

Fig. 1

a preferred embodiment of an internal combustion engine according to the invention in a schematic view,

Fig. 2

a schematic representation of the camshaft assembly in the internal combustion engine according to the invention Fig. 1 .

Fig. 3

a graphical representation of the valve movement of intake and exhaust valves of the various camshafts and the piston movement at an adjustment angle of 0 ° KW,

Fig. 4

a graphical representation of the valve movement of intake and exhaust valves of the various camshafts and the piston movement at maximum displacement in late and

Fig. 5

a graphical representation of the valve movement of intake and exhaust valves of the various camshafts and the piston movement at maximum displacement in the direction of early.

In the Fig. 1 illustrated, preferred embodiment of an inventive internal combustion engine comprises a cylinder head 10, are arranged in the non-illustrated working cylinder, in which each have a reciprocating piston (not shown) oscillating moves. The cylinder head 10 has an outlet side 12, at which exhaust gases are discharged from the working cylinders, and an inlet side 14, at which the working cylinders fresh gas is supplied.

Each cylinder is associated with two intake valves (not shown) and two exhaust valves (not shown), wherein a first camshaft 16 and a second camshaft 18 are provided. The first camshaft 16 carries inlet cams 20; each actuating an intake valve, and exhaust cams 22 each actuating an exhaust valve. Likewise, the second camshaft 18 carries intake cams 24, each actuating an intake valve, and exhaust cams 26, each actuating an exhaust valve. On both camshafts 16, 18, intake cams 20, 24 and exhaust cams 22, 26 alternate as seen in the longitudinal direction. In this way, the two intake valves and exhaust valves of each working cylinder are actuated by different camshafts 16, 18. As especially in addition Fig. 2 Thus, each of the camshafts 12, 14 is a so-called mixed camshaft, ie each camshaft 12, 14 actuates both intake and exhaust valves via respective intake cams 20, 24 and exhaust cams 22, 26, respectively.

The timing of the first camshaft 16 for the associated intake and exhaust valves are fixed unchangeable. Arranged on the second camshaft 18 is a phaser 28 which changes the timing of the intake and exhaust valves associated therewith with respect to the timing of the first camshaft 16 by rotating the second camshaft 18 by the phaser 28 relative to the first camshaft 16. The first camshaft 16 is the camshaft that is driven at 30 by a crankshaft, not shown, of the internal combustion engine. The first camshaft 16 in turn drives the second camshaft 18 via gears 32.

In the Fig. 3 to 5 is on a horizontal axis 34, a crank angle and a vertical axis 36, a lifting movement applied. On the horizontal axis 34 is at 38 a bottom dead center (UT) of the reciprocating before.dem charge change, at 40 an upper dead center (TDC) of the reciprocating piston during the charge cycle and at 42 a bottom dead center (UT) of the reciprocating piston applied after the charge cycle. A first graph 44 illustrates the lift 36 across the crank angle 34 for the piston, a second graph 46 illustrates the lift 36 over the crank 34 for those exhaust valves controlled by the exhaust cams 22 of the first cam 16, a third graph 48 (dashed line) FIG. 4 illustrates the lift motion 36 versus the crank angle 34 for those exhaust valves controlled by the exhaust cams 26 of the second camshaft 18. A fourth graph 50 illustrates the lift motion 36 versus the crank angle 34 for those intake valves that are from the intake cams 20 of the first camshaft 16 controlled and a fifth graph 52 (dashed) illustrates the lift 36 over the crank angle 34 for those intake valves controlled by the intake cams 24 of the second camshaft 18.

In Fig. 3 is a position of the adjuster 28 shown at 0 ° KW, ie, the camshafts 16, 18 are not rotated against each other. In Fig. 4 is a position of the adjuster at maximum displacement towards late and in Fig. 5 is a position of the adjuster at maximum adjustment shown in the morning. Like from the Fig. 2 to 5 immediately seen, the stroke of the valves of the first crankshaft 16 (second graph 46 and fourth graph 50) remains unchanged relative to the crankshaft, whereas the stroke of the valves of the second crankshaft 18 (third graph 48 and fifth graph 52 each dashed) together for the associated Inlet valves and exhaust valves are moved. As a result, a millereffect can be simulated on the one hand by the shifted opening times between the intake valves of the first crankshaft 16 (intake cam 20, fourth graph 50) and the intake valves of the second crankshaft 18 (intake cam 24, fifth graph 52). Fig. 3 On the other hand, a collision between the intake valves and the reciprocating piston is prevented.

The prerequisite for this simulated Miller is the presence of at least two intake valves per cylinder and one, preferably two exhaust valves per cylinder, the intake valves of each cylinder being actuated by different crankshafts. Here, a camshaft 16 serves half of all intake and exhaust valves with conventional timing. Alternatively, the inlet side is optimized for maximum filling at a specific operating point, for example for the cold start operating point. The second camshaft 18 operates the remaining intake and exhaust valves and is with respect to the cam contour for "exhaust valve closes" and "inlet valve opens" designed so that an adjustment of this camshaft 18 of about 60 ° CA +/- 20 ° can take place without piston collision ,

The Millereffekt is achieved in that the earliest "intake valve opens" associated with one camshaft 16 and the latest "intake valve closes" the other camshaft 18 different valves for each cylinder, see. Fig. 4 ,

An increase in the compression end temperature is possible in that at "intake valve closes" of the fixed camshaft 16 (fourth graph 50) in the UT 42, the second camshaft 18 (Miller shaft) is also moved in the direction of early (fifth graph 52; Fig. 5 ). At the same time, an increase of the exhaust gas temperature (important for exhaust aftertreatment) can be achieved by a premature pushing of the "exhaust valve opens" the Millerwelle 18 (third graph 48), as in Fig. 5 shown. This may assist a rapid heating of an exhaust catalyst after a cold start,

The first camshaft 16 has an ES at approx. = UT 42 in order to achieve the maximum compression ratio with advance adjustment of the second camshaft 18. Alternatively to the in Fig. 3 shown situation at 0 ° -Verstellung of the adjuster 28, this can also be considered as 0 ° position for the second camshaft 18, so that then only a retardation occurs. It is important in any case, however, that the intake cam of the first camshaft 16 is shortened in such a way in comparison to UT, for example in diesel engines at about 10 ° -25 ° CA to UT, that the UT position ES can be achieved by both cams.

FIG. 6 shows a portion of the second mixed camshaft 18, on which axially spaced, for example, four formed as a hollow shaft cam carrier 54 are arranged, wherein in Fig. 6 only one of the cam supports 54 is shown. The following description refers only to the illustrated cam carrier 54, but also applies to all other, not shown cam carrier on the second camshaft 18. The cam carrier 54 is axially displaceable on the second camshaft 18 but rotatably mounted. At both ends of the cam carrier 18 there is arranged a worm drive with an axial curve 56 or 68 designed as a depression or groove, which winds helically about a cam carrier axis. In other words, the grooves 56, 58 extend circumferentially around the cam carrier 54. On the cam carrier 54, two cams are arranged, with each cam from the same base circle axially offset two different cam tracks 60, 62 and 64, 66 emerge. The cylindrical region of the lateral surface of each cam piece 54 located between the two cams is designed as a bearing surface for a camshaft bearing 68.

Each cam carrier 54 is rotatably and axially displaceably mounted with this cylindrical bearing surface in a camshaft bearing block 68 of a cylinder head (not shown). The two camshaft bearing block 68 facing end faces of the cams are formed as contact surfaces 70 and 72. Accordingly, the cam-facing end faces of the camshaft bearing 68 are formed as a contact surface 74 and 76, respectively. The distance between the two contact surfaces 70 and 72 of the cams is greater than the distance between the contact surfaces 74 and 76 of the camshaft bearing 68. In this case corresponds to the maximum distance between the contact surfaces 70 and 72, and the contact surfaces 74 and 76 from each other, the width of the cam tracks 60, 62, 64, 66, as well as the distance that a cam carrier 54 can be displaced in the axial direction relative to the second camshaft 18 by the axial curves 56 and 58 of the worm gears. Gas exchange valve 78, 80 of the internal combustion engine are actuated by the cam via cam follower 82, 86, the Friction reduction with a roller 84 are formed. Here, for example, one gas exchange valve 78 is an inlet valve and the other gas exchange valve 80 is an outlet valve. Associated with the rocker arms 82, 86 is in a conventional known manner formed in the cylinder head clearance compensation element 88 and 90th

In the first position of the cam carrier 54, as in FIG Fig. 6 in which the contact surface 70 of the inlet cam 24 abuts the abutment surface 74 of the camshaft bearing 68, and in the second position of the cam carrier 54, in which the abutment surface 72 of the exhaust cam 26 abuts the abutment surface 76 of the camshaft bearing 68, the cam carrier 54 is respectively fixed in the axial direction by a releasable locking device, as in Fig. 6 is indicated in the broken outlet cam 26. In this way, the cam carrier 2 is fixed for both axial positions.

The adjustment of the Hubventilsteuerung of the in FIG. 6 shown. Operating state in the second position (not shown), takes place in that a driving pin 92 of a cylinder head arranged in the electric actuator 94, which is associated with the axial cam 56 engages in the formed as a recess or groove axial cam 56. As a result of the rotation of the camshaft 18 and the cam carrier 54, the cam carrier 54 is displaced axially to the left by contact contact between the driver pin 92 and the groove walls of the axial cam 56. It moves the contact surface 72 of the exhaust cam 26 to the contact surface 76 of the camshaft bearing 68 and comes into axial contact with this contact the cam carrier 54 is axially fixed in this second position corresponding to a second operating state of the Hubventilsteuerung. The driving pin 92 is pulled out by means of the electric actuator 94 in a known manner again from the formed as a circumferential groove axial cam 56. To adjust the lift valve control from the second position back to the in FIG. 6 shown first position corresponding to a first operating state of the Hubventilsteuerung, another driving pin 96 of the axial cam 58 associated and arranged in the cylinder head electrical actuator 98 is introduced by the actuator 98 in the recess formed as a groove or other axial cam 58.

By the rotation of the camshaft 18 via the contact contact between the groove walls of the axial cam 58 and the driving pin 96 of the cam carrier 54 in FIG. 6 axially displaced to the right, so that the contact surface 70 of the inlet cam 24 comes into contact with the abutment surface 74 of the camshaft bearing 68. The cam carrier 54 is fixed by the system between the contact surface 70 of the inlet cam 24 and the bearing surface 74 of Lagerbo3 camshaft bearing 68 on the one hand and by the locking device on the other hand axially in both directions. The driving pin 96 is pulled out by means of the electric actuator 98 in a known manner from the circumferential groove of the axial cam 58. The actuation of the electrical actuators 94, 98 is controlled in a known, not shown manner by an engine control unit, not shown.

The cam carrier 54 arranged on the second camshaft 18 can in this way be adjusted individually by the associated actuators 94 and 98, respectively, between their two operating positions for the stroke valve control. According to the invention, such a configuration of the adjustment of the Hubventilsteuerung for a both intake valves controlling and exhaust valves controlling mixed camshaft 18 is provided with camshaft adjuster 28.

LIST OF REFERENCE NUMBERS

10

cylinder head

12

outlet

14

inlet side

16

first camshaft

18

second camshaft

20

Intake cam of the first camshaft 16

22

Exhaust cam of the first camshaft 16

24

Intake cam of the second camshaft 18

26

Exhaust cams of the second camshaft 28

28

adjuster

30

Drive first camshaft 16

32

gears

34

horizontal axis: crank angle

36

vertical axis: lifting movement

38

bottom dead center (UT) of the reciprocating piston before the charge cycle

40

top dead center (TDC) of the reciprocating piston during the charge cycle

42

bottom dead center (UT) of the reciprocating piston after the charge change

44

first graph: stroke movement piston

46

second graph: stroke movement exhaust valves first camshaft 16

48

third graph: stroke movement exhaust valves second camshaft 18

50

fourth graph: stroke movement intake valves first camshaft 16

52

fifth graph: stroke movement intake valves second camshaft 18

54

cam support

56

groove

58

groove

60

Cam track

62

Cam track

64

Cam track

66

Cam track

68

camshaft bearings

70

Contact surface on the end face of the cams

72

Contact surface on the end face of the cams

74

Contact surface of the camshaft bearing 68

76

Contact surface of the camshaft bearing 68

78

Gas exchange valve / inlet valve

80

Gas exchange valve / exhaust valve

82

cam follower

84

role

86

cam follower

88

Lash adjuster

90

Lash adjuster

92

Carrier pin

94

actuator

96

Carrier pin

98

actuator

Claims (15)

Internal combustion engine, with at least one working cylinder, wherein each working cylinder at least two inlet valves (78) and at least one outlet valve (80) is associated with at least two camshafts (16, 18) are provided, of which at least one mixed camshaft (18) both at least one Inlet valve (78) and at least one exhaust valve (80) is actuated, wherein on at least one mixed camshaft (18) which actuates both at least one inlet valve (78) and at least one outlet valve (80), an adjuster (28) is arranged, which valve timing of the mixed camshaft (18) associated with intake and exhaust valves (78, 80) with respect to the valve timing of the at least one other camshaft (16) selectively adjusted early or late, characterized in that at least at the mixed camshaft (18) at least a cam carrier (54) is provided, the cam carrier (54) being movable relative to this mixed cam the at least one cam carrier (54) has at least one cam (24, 26) on which at least two subordinate cam tracks (60, 62, 64, 66) are arranged ), means (92, 96, 56, 58) for axially displacing the at least one cam carrier (54) relative to the blended camshaft (18) between a first axial position and at least a second axial position. Internal combustion engine according to claim 1, characterized in that the at least two different cam tracks (60,62,64,66) are arranged axially spaced and substantially parallel to each other. Internal combustion engine according to one of the preceding claims, characterized in that at least a first of the at least two different cam tracks (60,62,64,66) from a second of the at least two different cam tracks (60,62,64,66) on the cam (24,26) has a different radial distance from the axis of the mixed camshaft (18) and / or in the circumferential direction of the mixed camshaft (18). Internal combustion engine according to one of the preceding claims, characterized in that the at least one cam carrier (54) for supporting the at least one camshaft (18) of at least one cylinder head fixed Camshaft bearing (68) is included. Internal combustion engine according to one of the preceding claims, characterized in that the internal combustion engine comprises a plurality of working cylinders and the mixed camshaft (18) each comprises at least one cam (24, 26) for one of the working cylinders, wherein the mixed camshaft associated intake and exhaust valves (78,80) are simultaneously adjustable by pressing the adjuster either early or late. Internal combustion engine according to at least one of the preceding claims, characterized in that the adjuster (28) is designed such that it has an adjustment range for the valve control times of 60 ° CA +/- 20 °. Internal combustion engine according to one of the preceding claims, characterized in that at least one of the at least two different cam tracks (60,62,64,66) on a cam (24) for actuating an intake valve and at least one other of the at least two different cam tracks (60,62 , 64, 66) on a cam (26) for actuating an exhaust valve have different courses at a radial distance from the axis of the mixed camshaft (18) and / or in the circumferential direction of the mixed camshaft (18). Internal combustion engine according to one of the preceding claims, characterized in that the internal combustion engine comprises a plurality of working cylinders and at least one of the at least two different cam tracks (60,62,64,66) on a first cam (24,26) for actuating a on or an outlet valve of a first working cylinder and at least one other of the at least two different cam tracks (60,62,64,66) on a cam (24, 26) for actuating an inlet or outlet valve of a second working cylinder different courses at a radial distance from the axis of the Having mixed camshaft (18) and / or in the circumferential direction of the mixed camshaft (18). Internal combustion engine according to at least one of the preceding claims, characterized in that each exhaust cylinder associated with two exhaust valves (80), wherein two camshafts (16, 18) are provided, wherein a first camshaft (16) one half of the intake and exhaust valves and a second camshaft (18) actuates the other half of the intake and exhaust valves, wherein the first camshaft (16) fixed Having control times for this camshaft (16) associated valves and on the second camshaft (18) of the adjuster (28) is arranged. Internal combustion engine according to claim 9, characterized in that the second camshaft (18) is designed such that at an adjustment angle of 0 ° KW, the exhaust valves (80) associated with the second camshaft (18) close earlier than those associated with the first camshaft (16) Open exhaust valves and the intake valves (78) associated with the second camshaft (18) later and close later than the intake valves associated with the first camshaft (16). Internal combustion engine according to claim 9, characterized in that the second camshaft (18) is formed such that at an adjustment angle of 0 ° KW, the second camshaft (18) associated intake valves (78) simultaneously with the first camshaft (16) associated with inlet valves shut down. Internal combustion engine according to at least one of the preceding claims, characterized in that the means for axially displacing the at least one cam carrier relative to the mixed camshaft between a first axial position and at least a second axial position at least one axially fixed relative to the blended camshaft (18) and radially between a first and a second bolt position displaceable bolt (92) which engages in the second bolt position in a cam carrier on the (54) formed in the radial direction circumferential groove (56) and in the first bolt position of this groove (56) is spaced wherein the groove (56) is configured such that the cam carrier (54) shifts from an axial position on the blended camshaft (18) to a different axial position on the blended camshaft (18) when the bolt (92) slides in the groove (56) engages. Internal combustion engine according to claim 12, characterized in that at least one first pin (92) is provided, which selectively engages in a first groove (56) and at least one axially with respect to the mixed camshaft (18) of the first pin (92) spaced second pin (96) which selectively engages a second groove (58) spaced axially from the first groove (56) with respect to the blended camshaft (18), the cam support (54) extending from the first axial position on the blended camshaft (54). 18) moves to the second axial position on the blended camshaft (18) when the first bolt (92) engages the first groove (56) and from the second axial position on the blended camshaft (18) to the first axial position the mixed camshaft (18) moves when the second bolt (96) in the second groove (58) engages. Internal combustion engine according to one of the preceding claims, characterized in that the internal combustion engine is a diesel engine. Internal combustion engine according to one of the preceding claims, characterized in that the internal combustion engine is an internal combustion engine of a motor vehicle.

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