DE19629349A1 - Valve drive for internal combustion engine - Google Patents

Abstract

The valve drive has a poppet valve (12) actuated by a camshaft (34) for variable stroke movement. A drive transmission rocker has a contact face (80) for pressure transmission. The contact face is pivotable on the bearing axis of the camshaft. There is a first upper surface area (80.1) with a cylindrical curvature having the same axis as the cam shaft bearing. A second upper surface (80.2) does not have a cylindrical curvature and is connected to the first section. There can be a third surface (80.3) with a larger radius than that of the first.

Description

TECHNICAL AREA

The invention relates to a valve train and one with egg Such a valve train equipped cylinder head one Internal combustion engine. The valve train is between her at least one lift valve and its camshaft for control of the variable stroke pattern available.

STATE OF THE ART

Such a generic type is known from EP-A1 0 638 706 Valve train is known, with which a valve lift course Visibly adjustable stroke size and stroke duration. Of the Valve gear has a rocker arm that swings on one Bolt is suspended. The bolt is in an elongated hole in the Rocker arm stored and can be within the slot means of an eccentric press on the outside of the rocker arm Assume different positions. This is the position of the rocker arm's pendulum axis varies, depending on the position of the bolt within the slot. Of the Rocker arm carries a roller that is pressing on a cam wave is present. By means of their curved on their underside The rocker arm presses on the contact surface as a rocker lever designated another rocker arm, which in turn has a pressing effect on the globe valve. The one on the rocker arm and thus indirectly acting on the globe valve Contact surface area of the rocker arm includes an under different outer surface area of the rocker arm, depending on Position of the bolt within the elongated hole and thus depending depending on the respective self-aligning bearing. When adjusting the Self-aligning bearings can be both the maximum lifting height as well make the opening time of the globe valve variable, namely  in that when increasing the maximum stroke size too the opening time increases.

The elongated bolt bearing has a disadvantage Rocker arm. So can a game of bolts in Do not avoid elongated holes for reasons of assembly. This game increases when the internal combustion engine is operating Material wear in the area of line contact between Elongated hole and bolt. In connection with the tolerances of the ge there may be a curved contact surface on the bottom of the rocker arm thereby also when the cam takes effect with its Cam base circle come to a stroke movement of the valve. In Connection with the hydraulic built into the rocker arm Valve clearance compensation element may cause an unwanted stroke movement only a few hundredths in the upper resting point of the globe valve Amount to millimeters, otherwise it is called inflation of the hydraulic element can come. The latter would result in that the lift valve, for example the inlet valve, can no longer be closed completely.

From DE-A1 43 42 806 a valve train is known in which two rocker arms between the camshaft and the lift valve positio are nated. Those from opposite directions in between engaging space between the camshaft and valve train Rocker arms are adjustable around the camshaft. At this valve train changes the valve lift course hend that together with the maximum lifting height at the same time The stroke duration is also changed, in the same way Way, i.e. lifting height and lifting time simultaneously increased or be made smaller.

The valve train known from DE-Al 43 22 480 is required two camshafts to adjust the valve lift of one Valve. Depending on the mutual orientation of the concerned Cams of the two camshafts can be swiveled on one Variably designed valve pressing the swivel lever  to valve lift and valve opening time at the same time to adjust.

From DE-A1 29 51 361 a valve train is known with which the valve stroke curve of a globe valve is only in size can be adjusted. The valve train has two Swing levers that come from opposite directions in the tw Intervene between the camshaft and valve. The Swivel levers are arranged one above the other. During one The other swivel lever is pivoted bel designed with its axis of rotation. This longitudinally displaceable training requires a large one constructive effort. The cylinder is also laterally pierce the necessary construction elements. Apart from that, it is needed next to the cylinder head There is hardly any space required in today's engine compartments. Finally, there is also the practically existing point contact between the longitudinally movable pivot lever and the Ven til shaft unsuitable for large-scale production.

PRESENTATION OF THE INVENTION

The invention is based on this prior art the task of specifying a valve train that a Adjustment of the valve stroke and the valve opening time enabled in a constructively satisfactory manner and with the the most compact possible cylinder head designed can be.

This invention is for a valve train by the features of claim 1 and for a corresponding Zylin derkopf given by the features of claim 12.

Starting from EP-A1 0 638 706 mentioned at the beginning The prior art is characterized by the invention appropriate valve train through a contact surface of its pressure  Carrier from a first surface area and a subsequent second different one Has surface area, the first surface area rich a circular curvature, with the bearing axis as the longitudinal axis of the cylinder, and has the second surface richly deviating, not circular cylindrical Has curvature. As long as the pressure transmission device with their first surface area, that is with their circular cylindrical contact surface, on the globe valve works by scanning the rotating cam wave cam caused swiveling movement of the pressure transfer supply device and thus the contact area around this camp axis no lifting movement of the lifting valve, such as in particular an intake valve; the contact surface rolls on egg ner non-moving contact surface of the globe valve. Only when the pressure transmission device is more powerful steers, that is, is pivoted, and with which follows contact area, no longer circular cylinder is curved in shape, on the contact surface of the globe valve is present, a stroke movement of the valve can be generated. Each after alignment of the contact surface to the contact surface of the Lift valve, that is, depending on the "zero position" of the contact surface che and thus the pressure transmission device can the public a valve can be delayed. In addition, that can also Closing of the valve is earlier. This ver Adjustment options do not require an additional phase setting ler.

After an essential development of the invention closes a third surface on the curved contact surface area, which is also a circular cylindrical elbow Mung, and also with the bearing axis around which the pressure transmission device or its Contact surface swiveled as the longitudinal axis of the cylinder. This third surface area has a radius that is larger is as the radius of the first surface mentioned above kitchen area.  

As soon as the pivot lever with its contact surface in this third surface area arrives, which is a correspondingly large ßes pivoting of the pressure transmission device and thus assuming the contact area, this can be ge accordingly opened valve should be left in this position; the The contact surface rolls along on their contact surface the lift valve without an additional positive or negati ve to cause stroke movement of the valve. The valve can thus in its preferably maximum open position to remain for a certain period of time.

Due to the fact that a phase adjustment is made possible a changed opening or closing time of the globe valve in the valve according to the invention drive is not required, the camshaft can with non changes to be driven at constant speed. This allows to control a single camshaft both the intake and exhaust valves of an engine one To provide internal combustion engine. There will be space above the cylin the head of this engine is free, in which the valve train with its Pressure transmission devices can be placed. The be Required space above a cylinder head is when the namely the valve train according to the invention is practically not large ßer, so that a very slim cylinder head constructively can be formed.

The cylinder head designed according to the invention accordingly An internal combustion engine is characterized in that between the only camshaft and the at least one off let valve a known first valve train and that between this single camshaft and the at least one Inlet valve a second, the above fiction appropriate valve train is present. This second valve train has the above-mentioned pressure transmission device device with the curved contact surface pivotable by a bearing axis aligned parallel to the camshaft axis  is there. The pivotability of this curved contact surface can be changed both by changing the position of the contour a camshaft-cam sensing body as well one additionally acts on the pressure transmission device kende adjusting device can be effected. This allows in Dependence on that caused by the adjusting device Pivotal position of the contact surface is different Surface areas optionally for the by turning the Pressure transmission caused by cam are available.

With such a cylinder head, camshaft and ver control shaft at about the same height above the valves with ih essential components are present.

Further features and advantages of the invention are those in the Claims further listed features and the next to see existing embodiments.

BRIEF DESCRIPTION OF THE DRAWING

The invention is described below with reference to the drawing illustrated embodiments described and he purifies. Show it:

Fig. 1 shows a section through a camshaft of an internal combustion engine with a first embodiment of a valve gear according to the invention,

Fig. 2 shows a section through a camshaft and a Zylin The head of an internal combustion engine with a two-th embodiment of a valve train for gleichzei term operation of the existing inlet and outlet valves,

Fig. 3 is a schematic representation of the contour of the pressure acting on an inlet valve contact surface of an existing pressure transmission device in the valve train.

WAYS OF CARRYING OUT THE INVENTION

A section of a cylinder head 10 with an intake valve 12 is shown in FIG. 1 of an internal combustion engine. Above the cylinder head 10 and thus also above the intake valve 12, there is an overhead camshaft 34 , of which its axis 14 and one of several cams, an intake cam 16 serving to control the intake valve 12 , can be seen.

On the cam 16 , a roller 35 is rotatably attached, which is needle-supported in the present case. The axis of rotation 36 of the roller 35 is parallel to the axis 14 of the camshaft 34 and parallel to a further shaft 30 . This shaft 30 can be adjusted back and forth on a circumferential circle 31 with the radius R2 around the center point M (axis 14 ). For this purpose, the shaft 30 is attached to a swivel element 32 . This Schwenkele element 32 can be adjusted in a corresponding circular arc just about the axis 14 with a constant radius.

The adjustment of the pivot member 32 is relative to the respective rotational position of the camshaft 34 by means of an adjustment shaft 56 mounted on a gear 54 which meshes with egg ner existing on the pivot member 32 toothing 52 in mesh with the procedure. The gear 54 is fixed on the adjusting shaft 56 in a rotationally fixed manner. By turning the adjusting shaft 56 and thus the gear 54 , the pivot element 32 is thus adjusted relative to the camshaft 34 in one or the other direction of rotation.

On the shaft 30 , which is fixed to the pivot member 32 , a pivot lever 74 is rotatably mounted, which carries the roller 35 at its upper end in FIG. 1, which lies against the inlet cam 16 .

At the lower end in FIG. 1, one end of a push rod 76 presses against the pivot lever 74 . The other end of this push rod 76 presses against a swivel element 78 encircling the camshaft 34 in an annular manner. The pivot member 78 is relatively rotatably attached to the camshaft 34 . When rotating the camshaft 34 and rotating the inlet cam 16 accordingly, the pivot lever 74 is pivoted about the shaft 30 by the roller 35, depending on whether the cam 16 with its cam base circle 16.1 or its cam elevation 16.2 is in the region of the roller 35 . Accordingly, the push rod 76 presses more or less against the pivot element 78 . A rotation of the inlet cam 16, for example in the counterclockwise direction, will therefore push the push rod 76 to the right, as shown in FIG. 1, and thus pivot the pivot element 78 just about counterclockwise about the axis 14 (center point M).

The underside of the pivoting element 78 facing the inlet valve 12 has a specially shaped contact surface 80 . This contact surface 80 presses on a roller 82 which is rotatably held on a further rocker arm 84 . This lower cam follower 84 is located on the intake valve 12 from above at a contact surface 22nd This rocker arm 84 is pivotally mounted on a Hy drobolzen 23 . Depending on how far the roller 82 is pressed from above, the valve plate 40 of the valve 12 is moved more or less far away from the valve seat 42 and the inlet channel 44 is thereby opened to different lengths and lengths.

The contact surface 80 of the pivot member 78 has a he most surface area 80.1 , which has a circular cylindrical curvature with the camshaft axis 14 as a cylinder longitudinal axis. The radius of this cylindrical curvature sits the constant dimension RT (see also Fig. 3). This surface area 80.1 is followed by a further surface area 80.2 on the contact surface 80 , which has an alternating distance from the axis 14 . This second surface area 80.2 is followed by a third surface area 80.3 , which again has a circular cylindrical curvature, with the camshaft axis 14 as the cylinder longitudinal axis. The radius of this third surface area 80.3 has the constant dimension R3. R3 is larger than R1 of the first surface area 80.1 .

Rolling of the contact surface 80 on the roller 82 in the area of the first surface area 80.1 and the third surface area 80.3 causes no relative adjustment of the valve plate 40 with respect to its valve seat 42 during the rolling movement within these two partial areas 80.1 and 80.3 and thus no change in the stroke position of the inlet valve 12 . Only within the central surface area 80.2 does a rotation of the pivot element 78 and thus a pivoting of the contact surface 80 change the stroke position of the inlet valve 12 . This effect can be used in different ways.

In the closed position of the inlet valve 12 shown in FIG. 1, the roller 82 is not in the area 80.1 of the contact surface 80 . The anlie on the inlet cam 16 constricting roller 35 stands still in the area of the cam base circle 16.1. With a rotation of the camshaft 34 in the counterclockwise direction and thus also in the rotation of the inlet cam 16 in the counterclockwise direction, roller 35 will roll for a while in the area of the cam base circle 16.1 of the inlet cam 16 . Only when the roller 35 comes into the region of the cam elevation 16.2 from the inlet cam 16 , the pivot lever 74 is pivoted ver about the shaft 30 in the counterclockwise direction, and thus also the pivoting element 78 is pivoted via the push rod 76 with the contact surface 80 in the counterclockwise direction. Then the different, increasing distances from the axis 14 having the second upper surface area 80.2 successively come into contact with the roller 82 of the lower rocker arm 84 . As a result, the inlet valve 12 is opened further and further in succession. The opening of the inlet valve 12 is delayed until the point at which the inlet cam 16 with its cam elevation 16.2 has reached the area of the roller 35 .

If the pivoting element 78 is pivoted so far in the counterclockwise direction that the third surface area 80.3 comes into contact with the roller 82 , the then before existing, open position of the inlet valve 12 is not changed; pivoting of the swivel element 78 in the swivel area in which the third surface area 80.3 is in contact with the roller 82 does not cause a change in the stroke position of the inlet valve 12 because of the cylindrical curvature of this third surface area. The open inlet valve 12 will therefore remain in its open position as long as the third surface area 80.3 is in contact with the roller 82 . In this way, a maximally opened inlet valve 12 can be kept open uniformly over a predetermined period of time. Only when swinging back the pivot element 78 in a clockwise direction, which is caused by a rolling of the roller 35 from the cam elevation 16.2 in the direction of the cam base circle 16.1 , can the inlet valve 12 move back into its closed position in FIG. 1.

The pivoting element 32 , which is not shown in more detail, can be held on a part that includes the camshaft 34, for example. The adjusting shaft 56 , which allows a pivoting of the pivot element 32 relative to the alignment of the camshaft 34 , can be rotated in the usual way.

Instead of the roller 35 , the pivot lever 74 can also bear against the camshaft 34 with a correspondingly shaped sliding surface. In addition, the contact surface 80 can also rest against a cup tappet provided for example for hydraulic play compensation of an inlet valve.

In Fig. 2, a cylinder head 10.2 , each with an inlet valve 12.2 and an exhaust valve 13.2 can be seen. A rocker arm 84 lies on the inlet valve 12.2 , as has already been described above in connection with FIG. 1 for the inlet valve 12 there. The existing on the rocker arm 84 ne roller 82 is from below on the contact surface 80 , which in turn has three surface areas 80.1 , 80.2 and 80.3 . These three surface areas are arranged from left to right in FIG. 2, while they are arranged from right to left in FIG. 1.

The contact surface 80 is part of a swivel element 78.2 which surrounds an adjusting shaft 56.2 in a ring shape , rotatable relative to the same. Against an extension 90 of this Schwenkele element 78.2 presses a compression spring 92 from below, which is supported with its lower end on the cylinder head 10.2 . The compression spring 92 wants to rotate the swivel element 78.2 counterclockwise around the adjusting shaft 56.2 .

On the adjusting shaft 56.2 there is a pivoting lever 94 which projects in a rotationally fixed manner and, in the present example, projects obliquely into the area between the two valves 12.2 and 13.2 . At the free end of this pivot lever 94 , a rocking lever 96 is rotatably held. At the free end 98 of the rocker arm 96 , the roller 35 is rotatably mounted on the one hand, which abuts the inlet cam 16 , and the one end of a push rod 76.2 is mounted. The other end of this push rod 76.2 presses against the swivel element 78.2 . The push rod 76.2 thus presses clockwise against the swivel element 78.2 . When rolling along the roller 35 to catch the inlet cam 16 so when turning the inlet cam 16 clockwise the roller 35 when it comes into contact with the cam elevation 16.2 , the push rod 76.2 to the right and thus the pivoting element 78.2 clockwise sense around the Axis 100 of the adjusting shaft 56.2 rotated. So that one after the other, with correspondingly further adjustment of the push rod 76.2 to the right, the surface areas 80.1 , 80.2 and possibly 80.3 come into contact with the roller 82 , as described above in connection with FIG. 1. In this way, the inlet valve 12.2 can be adjusted as well as the inlet valve 12 described in connection with FIG. 1.

In addition, an exhaust cam 116 is also present on the only camshaft whose camshaft axis 14 is drawn. This outlet cam 116 abuts a roller 182 on a rocker arm 184 , which in turn presses against the outlet valve 13.2 . This control of the outlet valve 13.2 by means of the outlet cam 116 is known.

Significant in the present case, however, is that the intake and exhaust valves 12.2 , 13.2 arranged in the cylinder head 10.2 are controlled by a single camshaft. While the exhaust valve 13.2 is driven by the camshaft (camshaft axis 14 ) positioned above this exhaust valve 13.2 (camshaft axis 14 ) in a manner known per se, the same camshaft is also used to control the opposite intake valve 12.2 . The valve train required for this is arranged in the area above the two valves 12.2 , 13.2 and ne ben of this camshaft. The cylinder head 10.2 can build very slim upwards. This is also possible in particular in that a phase adjustment of the inlet valve 12.2 for changing the opening start or opening end is not necessary, since this can be effected by the adjusting shaft 56.2 , which is positioned instead of a second cam shaft. Such a cylinder head can therefore be built extremely compact. Nevertheless, the intake valves in stroke amplitude and opening duration can be actuated variably via mechanical transmission elements. A constant opening position of the inlet valve is also possible in connection with the surface area 80.3 of the contact surface 80 . The components of the valve train are short and compact, so that a natural vibration of the Tei le can practically not occur.

The contact surface 80 is shown enlarged again in FIG. 3. In a first surface area 80.1 there is a circular cylindrical surface with a constant radius R1. The surface area 80.1 is followed by a second surface area 80.2 , the distance from the center point M of which increases. The third surface area 80.3 is in turn followed by a circular cylindrical surface with a constant radius R3. In the area of the transition arc, which is between the two cylindrical surface areas 80.1 and 80.3 , there is a different distance from the center M. As long as the circular cylindrical surface areas 80.1 and 80.3 roll on the roller 82 ( FIGS . 1, 2), there is no relative adjustment of the globe valve 12 or 12.2 . Only in the contact area of the transition sheet, the central surface area 80.2 , there is an adjustment of the inlet valve 12 or 12.2 , as described above in connection with FIGS . 1 and 2.

There is the possibility of valve shutdown by the roller 82 per cycle only running in the area 80.1 of the contact surface 80 .

The pivoting of the pivot elements 32 , 94 is used with a suitable design of the components and corresponding direction of rotation of the camshaft not only to change the maximum stroke and opening duration, but also changes the phase position of the respective maximum stroke relative to the camshaft / crankshaft so that particularly favorable engine operating points Visible fuel consumption and exhaust emissions can be shown without an additional twisting device of the intake camshaft.

Claims (14)

1. valve train of an internal combustion engine, which is present between its at least one lift valve ( 12 ) and its camshaft ( 34 ) for controlling the variable stroke profile,

• - With a pressure transmission device which presses against the lifting valve ( 12 ) and which is pivotable ver about a bearing axis aligned parallel to the camshaft axis ( 14 ),
• with a contact body ( 35 ) which bears against a cam ( 16 ) of the camshaft ( 34 ) and which causes the pressure transmission device to pivot when it changes position by rotating the cam ( 16 ),
• - The pressure transmission device has a contact surface ( 80 ) through which the pressure transmission can be set forth, characterized in that
• - The contact surface ( 80 ) pivotable about the bearing axis ( 14 , 100 ) at least
• a first surface area ( 80.1 ), which has a circular cylindrical curvature, with the bearing axis ( 14 , 100 ) as the longitudinal axis of the cylinder,
• - A second surface area ( 80.2 ) which adjoins the first surface area ( 80.1 ) and which has a non-circular cylindrical curvature.

2. Valve train according to claim 1, characterized in that

• - The contact surface ( 80 ) has a third surface area ( 80.3 ), which also has a circular cylindrical curvature, also with the bearing axis ( 14 , 100 ) as the longitudinal axis of the cylinder, wherein
• - The radius (R3) of this third surface area ( 80.3 ) is larger than the radius (R1) of the first surface area ( 80.1 )
• 3. Valve train according to one of the preceding claims, characterized in that
• - Contains the pressure transmission device
• a swivel element ( 78 ) having the contact surface ( 80 ),
• - Pressure transmission members ( 74 , 76 ; 76.2 , 96 , 94 ), through which on the one hand the pressure transmission between the body ( 35 ) bearing against the cam ( 16 ) and the swivel element ( 78 ) can be produced, and through which, on the other hand, the swivel of the swivel element ( 78 ) about the bearing axis ( 14 , 100 ) can be produced.

4. Valve train according to claim 3, characterized in that

• - The bearing axis is the camshaft axis ( 14 ), so that the pivot element ( 78 ) about the camshaft ( 34 ) is pivotable ver,
• - A swivel lever ( 74 ) which can be swiveled around another shaft ( 30 ) with its one end region pressing against which the contact surface ( 80 ) has swivel element ( 78 ), and at the other end region of which the body ( 35 ) bearing against the cam ( 16 ) ) is attached,
• - The shaft ( 30 ) concentrically to the camshaft ( 34 ) ver adjustable, namely along the circumference of a circle ( 31 ) with the radius (R2), the center of which is the axis of rotation ( 14 ) of the camshaft ( 34 ).

5. Valve train according to claim 4, characterized in that

• - A push rod ( 76 ) between the pivot lever ( 74 ) and the pivot element ( 78 ) is present.

6. Valve train according to claim 4 or 5, characterized in that

• - An adjustment device for the swivel lever ( 74 ) is available before, with which its orientation to the camshaft axis can be changed.

7. Valve train according to claim 6, characterized in that

• - An arbitrarily rotatable adjusting shaft ( 56 ) with parallel alignment next to and at a distance from the camshaft ( 34 ) is present,
• - A transmission connection between the adjusting shaft ( 56 ) and the pivot lever ( 74 ) is present.

8. Valve train according to one of the preceding claims, characterized in that

• - The bearing axis ( 100 ) axis of rotation of a parallel and at a distance from the camshaft axis ( 14 ) aligned, be arbitrarily rotatable adjusting shaft ( 56.2 ),
• - The swivel element ( 78.2 ) having the contact surface ( 80 ) surrounds the adjusting shaft ( 56.2 ) in a ring and is pivotably mounted to the adjusting shaft ( 56.2 ),
• - The body ( 35 ) resting on the cam ( 16 ) is supported on the one hand on the adjusting shaft ( 56.2 ), on the other hand presses against the swivel element ( 78.2 ).

9. Valve train according to claim 8, characterized in that

• - On the adjusting shaft ( 56.2 ) a first pivot lever ( 94 ) is attached, on which a rocker arm ( 96 ) is pivotally held,
• - The body ( 35 ) bearing against the cam ( 16 ) is mounted on the rocker arm ( 96 ),
• - The rocking lever ( 96 ) by means of a push rod ( 76.2 ) is pressed on the pivoting element ( 78.2 ) to be supported.

10. Valve train according to claim 8, characterized in that

• - The swivel element ( 78,2 ) has a cantilever arm ( 90 ) which is supported on an elastically deformable pressure member ( 92 ).

11. Valve train according to one of the preceding claims, characterized in that

• - The contact surface ( 80 ) pressing directly on the valve ( 12 ) or indirectly by means of known transfer elements such as, for example, by means of a roller drag lever ( 84 ) on the valve ( 12 ).

12. Cylinder head of an internal combustion engine

• - With at least one inlet ( 12.2 ) and one outlet valve ( 13.2 ),
• - with a camshaft to control the stroke of the valves ( 12.2 , 13.2 ),
• - With a valve train between this camshaft and the respective valve, according to one of the preceding claims, characterized in that
• - Between this one camshaft and the at least one exhaust valve ( 13.2 ) a valve drive known per se and first Ven
• - A second valve train is present between this one camshaft and the at least one inlet valve ( 12.2 ),
• - This second valve train has the pressure transmission device, which bears with the curved contact surface ( 80 ) on the inlet valve ( 12.2 ) and which is pivotable about a bearing axis ( 14 , 100 ),
• - This pivotability both by the position change tion of the contour of a cam ( 16 ) of the camshaft sensing body ( 35 ) and by an additional acting on the pressure transmission device Ver adjusting device (adjusting shaft 56, 56.2) can be produced, so that
• - Depending on the pivoting position caused by the adjusting device on the pressure transmission device existing contact surface ( 80 ) whose different surface areas ( 80.1 , 80.2 , 80.3 ) are available for the pressure transmission caused by turning the cam.

13. Cylinder head according to claim 12, characterized in that

• - there are at least two lift valves ( 12.2 , 13.2 ) aligned at an acute angle to each other,
• - About a valve ( 13.2 ) the camshaft and about above the other valve ( 12.2 ) the Verstellwel le is arranged.

14. Cylinder head according to claim 13, characterized in that

• - The camshaft and the adjusting shaft are approximately at the same height above the valves.

15. Cylinder head according to claim 13 or 14, characterized in that

• - The pressure transmission device is essentially present between the camshaft and the adjusting shaft.