DE102009037496A1 - Valve gear of an internal combustion engine - Google Patents

Abstract

The variable dual overhead camshaft valve gear (1) has a disconnected supporting element for each cylinder, which is inserted in a support of a cylinder head seated between two gas channels. A rocker finger (10) is supported at an end (11) on the supporting element.

Description

Field of the invention

The The invention relates to a variable cam follower valve train Internal combustion engine, with two identical gas exchange valves per cylinder and with disconnectable support elements.

Background of the invention

at Cam follower valves of variable design, which at this point need not be explained in more detail, occur especially in those with external disconnectable Abstützelementen considerable space problems. These switchable elements build wider and deeper than non-switchable "classic" elements. Thus, these are with their shots in many cases too close (above or to the side) to gas channels of the cylinder head. Optionally, a subsequent implementation of turn-off Support elements in existing and still to be enlarged Recordings of the cylinder head not possible.

in addition comes the increased construction and cost. This means, that per cylinder with two equally acting gas exchange valves themselves two drag levers with two disconnectable support elements in two shots prove necessary.

Object of the invention

task The invention is therefore to propose a variable valve train, used in cramped cylinder head conditions can and whose construction costs and costs keep within limits.

Solution of the task

According to the invention this task by the combination of a disconnectable support element with only one drag lever for two equally effective Gas exchange valves per cylinder of the internal combustion engine solved, which drag lever is shown either as a fork rocker arm is, at the other end at the same time two equally effective Gas exchange valves actuated or which rocker arm as a "classic" bar-shaped Component is present and at its other end to a gas exchange valves connecting cross strut acts and wherein the support element in a seated between two gas channels recording the Cylinder head is implemented, which recording according to a preferred embodiment of the invention preferably lower than a top of the gas channels lies.

Consequently the disadvantages described above are eliminated. It is ever Cylinder only a disconnectable support before whose Recording between two gas channels runs.

It is obvious that due to the reduced number of parts compared the prior art, the assembly costs and costs are reduced.

proposed are two variants for the overhead drag lever. According to a first variant of the drag lever have in the area of its other end a cross strut, the integral part of this is and with their bottom on the same effect Gas exchange valves acting in the hoist. The drag lever has this in plan view a fork-like geometry. According to one second variant, the drag lever is a "classic", Bar-shaped component from mass production provided, in the area of his other end on a separate crossbar acting, which bypasses the respective gas exchange valves.

To Another proposal is the drag lever made of inexpensive sheet metal exist and for example be punched from a board or tape.

to Representation of a stiff and thin-walled profile for The rocker arm is a U or H-profile in question. Possibly is also an inverted U-profile conceivable and provided.

As Abstützbarer Abschaltbarer design is a well-known from the prior art component in question (see, for example. DE 102 47 949 A1 ). This can ultimately be used unaltered and possibly hinged to the rocker arm as a unit to be delivered.

One particularly low-friction cam tap on the cam follower is then before, if the rocker arm for this purpose with a rotatable Roll is provided. Alternatively, it is also a sliding surface intended.

After all should the support element with a hydraulic lash adjuster be provided so that mechanical clearance measures unnecessary. However, it is also proposed every contact surface the drag lever at the other end with a hydraulic clearance compensation element to provide what its misalignment with uneven Elongation of gas exchange valves possibly prevented.

about the proposed inventive design in particular, a cylinder shutdown should be realized, so as it makes sense in internal combustion engines with a cylinder number> 5; however not exclusively.

Short description of the drawing

The The invention is explained with reference to the drawing. Show it:

1 a spatial view of the valve gear according to the invention;

2 a disconnectable support element of the valve train in longitudinal section and

3 in a schematic representation of a plan view of a cylinder head section with valve train.

Detailed description the drawing

Is shown in 1 a variable valve train 1 an internal combustion engine. As 3 This shows in more detail, are per cylinder 4 two in the camshaft direction one behind the other, equivalent gas exchange valves 2 . 3 intended. These lead to schematically drawn gas channels 6 . 7 ,

On the gas exchange valves 2 . 3 is a fork-like drag lever 10 with one at the other end 15 trained cross strut 14 on. A lateral guidance of the finger lever 10 on the gas exchange valves 2 . 3 is through guide tabs 19 realized. The latter go, as closer in 1 revealed, from an end-face 20 of the rocker arm 10 on the other end 15 out and are on a bottom 18 of the rocker arm 10 bent. A tour takes place on insides 21 the gas exchange valves 2 . 3 ,

In the area of an end 11 is the drag lever 10 with its bottom 18 on a head of a disconnectable support element 5 on. The support element 5 is with his recording 8th optimally accurate between the gas channels 6 . 7 positioned (see 3 ). A reason of its inclusion 8th can thus also deeper than a top of the gas channels 6 . 7 run.

The aforementioned cross strut 14 of the rocker arm 10 However, it can also be designed separately, so that the drag lever 10 with its other end 15 on a top of the crossbar 14 acting, in which case the drag lever 10 a completely elongated, beam-like design has.

The rocker arm 10 consists of thin-walled sheet steel and has two upright side walls 17 through a transom 16 are connected so that there is a U-shaped profile in cross section. From 1 an obvious role in the rocker arm 10 forms a cam contact surface 13 for a not shown lifting cam of a corresponding intake or exhaust camshaft (DOHC valve train).

The closer 2 apparent support 5 disconnectable type is not described in detail here, because it is well known to the art. Essentially, it consists of a pot-like housing 22 that in the recording 8th of the cylinder head 9 sitting. In the case 22 is telescopically an interior element 23 installed, which radially extendable coupling means 24 Has. In the shutdown case, the coupling means 24 via hydraulic fluid pressure so retracted that the inner element 23 an idle stroke with respect to the housing 22 completes, being used as a pivot point for the drag lever 10 then the gas exchange valves 2 . 3 count, which thus remain closed.

Of course, an insert of the valve drive proposed here 1 also conceivable and provided with cylinder heads with internal support elements.

LIST OF REFERENCE NUMBERS

1

valve train

2

Gas exchange valve

3

Gas exchange valve

4

cylinder

5

supporting

6

gas channel

7

gas channel

8th

admission

9

cylinder head

10

cam follower

11

one The End

12

top

13

Cam contacting surface

14

crossmember

15

other The End

16

crossbeam

17

Side wall

18

bottom

19

guide tab

20

Endstirn (other end)

21

inside

22

casing

23

inner element

24

coupling means

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10247949 A1 [0011]

Claims (9)

Variable DOHC valve train ( 1 ) an internal combustion engine for the simultaneous admission of two equally acting gas exchange valves ( 2 . 3 ) per cylinder ( 4 ), with this a turn-off support element ( 5 ) per cylinder ( 4 ) placed in one between two gas channels ( 6 . 7 ) seated intake ( 8th ) of a cylinder head ( 9 ) is installed, wherein on the support element ( 5 ) a drag lever ( 10 ) at one end ( 11 ) is mounted on the top ( 12 ) a cam contact surface ( 13 ) is intrinsic and wherein the gas exchange valves ( 2 . 3 ) by an overlying transverse strut ( 14 ), which is either present separately or from the drag lever ( 10 ) with its other end ( 15 ) or the integral part of the rocker arm ( 10 ) at the other end ( 15 ). Valve gear according to claim 1, wherein the respective receptacle ( 8th ) with the supporting element ( 5 ), based on an area between a camshaft axial line and a longitudinal center line of the cylinder head ( 9 ), positioned outside. Valve gear according to claim 1, wherein the respective receptacle ( 8th ) is lower than an upper side of the laterally adjacent gas channels ( 6 . 7 ). Valve gear according to claim 1, wherein the drag lever ( 10 ), in the case of one-piece connection with the transverse strut ( 14 ), a) from two by a crossbeam ( 16 ), upright side walls ( 17 ), b) has a U or H profile in cross-section, c) at its one end ( 11 ) is narrow in a top view in plan view and d) towards the other end ( 15 ), starting at or after the cam contact surface ( 13 ), for forming the transverse strut ( 14 ), funnel-shaped or fork-shaped. Valve gear according to claim 1 or 4, wherein on a lower side ( 18 ) of the transverse strut ( 14 ) two guide straps ( 19 ), which are either in one piece from an end-face ( 20 ) of the transverse strut ( 14 ) on the other end ( 15 ) and go to the bottom ( 18 ) bent or the one-piece from the bottom ( 18 ), which guide tabs ( 19 ), based on a longitudinal center plane through the drag lever ( 10 ), either on the inside or both on the outside ( 21 ) of the gas exchange valves ( 2 . 3 ) are guided. Valve gear according to claim 1, wherein the drag lever ( 10 ), in the case of the separate formation of the transverse strut ( 14 ), is continuously narrow beam-like, consists of two connected by a cross bar, upright and at least largely equally spaced side walls and wherein the drag lever ( 10 ) forms in cross section a U, H or an inverted U-profile. Valve drive according to one of claims 1, 4 or 6, wherein the drag lever ( 10 ) consists of thin-walled lightweight material such as sheet steel. Valve gear according to claim 1, wherein as a cam contact surface ( 13 ) is a roller bearing or roller bearing role. Valve gear according to claim 1, wherein the supporting element ( 5 ) is provided with hydraulic valve clearance compensation.

Images