DE102004040652A1 - Completely-variable five-section valve gear for internal combustion engine, includes guide rocker, moving connection adjuster, control pawl and cam track - Google Patents

Abstract

An intermediate section formed by a rocker lever (3) has a cam-actuated contact surface (3g). On one side of the pivotal axis (C3) it has a guide rocker (3a). On the other side of the axis is a control pawl (3b). The guide rocker is pivotally connected to the adjuster (2) at the end remote from the axis. The adjuster varies the position of the moving connection. The control pawl (3b) is supported at the end facing away from the axis (C3) by a support roller (3h) on a center (C3a) or by a circular sliding surface with a center (C3a) on a cam track (4a) fixed to the casing. The cam track form is a circular curve. When the valve has come to rest, this lies concentric with the center of rotation (C5) of the roller of the valve operating section (5). This roller is in driven connection with a control curve (3f) of the control pawl (3b). The curve (3f) transitions from a valve dwell section (3c) describing a radial contour about the center (C3a), through a run-on ramp (3d) which departs from he radial contour, into a lifting section (3e).

Description

The The invention describes a fully variable five-membered valvetrain Internal combustion engine.

With Such a fully variable valve train can be in particular a spark ignition Operate engine throttle free, which manages the with conventional throttling over wide load conditions to minimize occurring charge exchange losses. This is possible improve the performance and torque characteristics as well as fuel consumption and reduce pollutant emissions.

Furthermore is characterized by such a fitted internal combustion engine in the lower Speed range through improved response and a increased Smooth running out.

The Load is at a fully variable valve train through the opening cross-section determines the respectively adjusted elevation curve of the intake valve.

Around to allow throttle-free operation in idle and part-load range, It is advantageous, in addition to the valve lift and the opening duration (Event) To reduce the greatest possible potential of the throttle-free To develop load regulation, it is desirable here in the idling and part load range, the inlet valve as possible early to shut down.

From the DE 100 06 018 A1 (INA Ecovalve - system) is known in the art, a so-called five-member fully variable valve train, in which between the camshaft and a roller rocker arm, a two-piece intermediate member is connected, which consists of a pivotable about an adjusting, acted upon by the camshaft rocker arm and a pawl, which is pivotally mounted at a free end of the rocker arm, wherein the pawl with a roller scans a locking mountain, which can be rotated about the bearing axis of the adjusting by an adjusting device.

The Jack acts over here an attack surface, which during the valve catch is arranged concentrically to the adjusting shaft, on a roller rocker arm, which operates the lift valve.

With This valve drive can both the lifting height and the opening time (Event) from a maximum lift curve to a valve shutdown be varied.

Around Here is a desired Control strategy of the "early intake concludes "being able to realize is For this purpose, the camshaft with a separate Phasenverstelleinrichtung provided, with a relatively large Adjustment angle can be represented by the phase adjustment got to.

tasks The invention is a five-membered to provide fully variable valve train, wherein during the Adjustment of stroke and event at the same time a phase adjustment caused by the movement of the gear members.

hereby Ideally, with an optimal design, it can completely disappear a separate Phasenverstelleinrichtung be waived, or at least one phase adjustment device with a much smaller Adjustment angle than in the aforementioned prior art use Find.

According to the invention this Problem solved by the features of claim 1. advantageous Embodiments are shown in the subclaims.

A preferred embodiment possibility and the operation of the valve train according to the invention should with the help of 1 be explained in more detail.

It becomes the control mechanism of two intake valves operated in parallel 7 a single cylinder, wherein the valve train is preferably provided for multi-cylinder engines.

The 1 shows the valve train from the front of the cylinder head during the Grundkreisphase, with the eccentric, adjusting shaft 2 is adjusted in its angular position to a maximum stroke.

In a cylinder head is a, about the axis C1 rotating camshaft 1 intended.

The camshaft 1 is provided with two axially arranged in the Hubventilebene cams, each with a cam roller 3g a two-piece link 3 in operative connection.

The intermediate link 3 is as a toggle 3 configured and consists on the one hand of a guide rocker 3a , which is located axially in the center of the cylinder plane, as well as two axially offset, arranged in the Hubventilebenen control pawls 3b , where the guide rocker 3a pivot via a connecting bolt with the center C3 moving with the two tax pawls 3b connected is.

Advantageously, the two cam rollers 3g axially mounted in a respective valve plane on this connecting bolt.

The guide swing 3a is with her, the articulated connection C3 remote end in the embodiment of the eccentric as the eccentric shaft 2 designed adjusting shaft 2 pivotally mounted, with the adjusting shaft 2 preferably extends over several cylinders.

The adjusting shaft 2 is here rotatably mounted about the stationary bearing axis C2 in the cylinder head and is in driving connection with an unspecified electromechanical or hydraulic adjusting device (actuator) of known type.

The two tax pawls 3b are based with their articulated connection C3 facing away from the end preferably via a support roller 3h or alternatively via a circular arc-shaped sliding surface with a center C3a on one, firmly attached to the cylinder head structure or on one integrated in the cylinder head structure, eg cast-gate track 4a from.

Every slide track 4a is preferred on a manufactured from steel backdrop block 4 provided, which advantageously extends in its longitudinal axis over a plurality of cylinders.

The tax pawls 3b are on their the lift valves 7 Assigned side each with a control cam 3f provided, which each with a roller of a roller cam follower 5 in operative connection, wherein the two roller rocker arms 5 with its free end on each one lift valve 7 act and with their housing-side end on each support 6 with hydraulic valve clearance compensation.

The control curve 3f one control pin each 3b in this case goes from a valve latch section 3c which describes a radius contour around the center C3a, via a starting ramp deviating from the radius contour 3d in one, in the direction of the roller rocker arm 5 extending, lifting section 3e above.

The slide track 4a is here by a circular arc-shaped contact surface 4a formed, wherein the circular arc portion during the valve latch concentric with the bearing axis C5 of the roller of the roller finger follower 5 is located.

Furthermore, there is a so-called lost motion element 8th provided, which is formed in the embodiment by a compression spring, which is guided on a pin construction.

This lost-motion element 8th is arranged axially between the valve springs and in this case with its two ends articulated between the cylinder head housing structure and the guide rocker 3a supported and biased, whereby always a full contact between the cam rollers 3g and the cam surfaces of the camshaft 1 is guaranteed.

In the following it is assumed that the valve gear in the in 1 is shown position.

Will now the camshaft 1 offset in a rotation counterclockwise, so after the base circle phase, the two cams on the two cam rollers 3g effective, wherein over the connecting bolt, the two control pawls 3b be taken along and at the same time the guide swing 3a around the center of the eccentric of the adjusting shaft 2 is deflected.

This steering the tax pawls 3b around the bearing axis C3a of the support rollers 3h from, at the same time the support rollers 3h through the arcuate trajectory of the connecting axis C3 over a very small distance along the slide tracks 4a to roll back and forth.

Due to the deflection of the control latches 3b Here are the first ramps 3d and subsequently the lifting sections 3e the cams 3f on the rollers of the roller rocker arms 5 effective, which are thereby deflected maximum and the globe valves 7 open maximum.

In the further course, the cam rollers roll 3g along the descending flanks of the cam to the base circle position, the toggle lever ( 3 ) resumes its initial position and the globe valves 7 be closed again.

The following is the adjustment shaft 2 about the adjustment rotated by 180 degrees, for example.

This is due to the displacement of the eccentric of the toggle 3 in its entirety shifted to the left.

Here, the cam rollers roll 3g along the camshaft, which is caused by the changed contact point in conjunction with the direction of rotation of the camshaft, a significant phase change in the direction of "early".

At the same time, the outriggers are rolling roll 3h the tax pawl 3b along the slide tracks 4a from, in addition to the rollers of the roller rocker arms 5 along the valve gate sections 3c roll over, creating the contact point of the valve latch sections 3c is changed relative to the Schlepphebelaufrollen.

Will now the camshaft 1 again offset in a counterclockwise rotation, so after the base circle phase, the cams again on the two cam rollers 3g effective, wherein over the connecting bolt, the two control pawls 3b be taken along and at the same time the guide swing 3a is deflected around the center of the eccentric.

This steering the tax pawls 3b again about the bearing axis C3a of the support rollers 3h from, at the same time the support rollers 3h through the arcuate trajectory of the connecting axis C3 over a very small distance along the slide tracks 4a to roll back and forth.

During the deflection of the control pawls 3b have the rollers of the roller rocker arms 5 however, due to the changed location allocation relative to the tax pawls 3b only contact with the valve locking sections 3c , causing the roller rocker arms 5 not be deflected and the globe valves 7 remain completely closed. (Lift valves switched off)

The inventive solution can be defined by rotating the adjusting 2 within an adjustment angle on the one hand, the duration of the opening (event) and the lifting height of the applied lift valve 7 vary continuously.

in this connection is in a valve train in a kinematic according to the invention Design a phase shift during Ventilhub- and event adjustment causes.

in the following should be closer on some of the embodiment different execution options To be received.

In the previous embodiment, that is, with the guide rocker 3a in drive connection adjusting means 2 through an eccentric shaft 2 formed, in principle, however, other, relative to the cylinder head structure displaceable means may be provided, with which the guide rocker 3a articulated is connected.

In particular, here slidably guided plunger are considered here in the cylinder head, which with a free end via a joint with the guide rocker 3a are connected and linearly displaceable by per se known adjusting devices (eg hydraulically by piston - cylinder, mechanically by movement thread or by toothed racks - toothed shaft connection).

A Such a configuration is particularly envisaged when a cylinder-selective load control is to be carried out, which in particular also a selective cylinder deactivation is possible.

in this connection is ever an adjustment per cylinder and provided with one provided separate actuator.

Basically, the cam roller 3g be replaced by a correspondingly shaped sliding surface in the valve train.

Also are also other combinations of axial arrangements or number the gear members (e.g., two axially juxtaposed guide wings per cylinder) conceivable.

Further from the embodiment deviating and / or alternative design options are shown in the subclaims.

Claims (8)

Fully variable five-member valve train with a camshaft rotating about an axis C1 ( 1 ) and at least one, provided with a roller valve actuator ( 5 ), which on the free end of at least one lift valve ( 7 ), wherein between the camshaft ( 1 ) and the valve actuator ( 5 ) a two-part, in an axis C3 hingedly connected intermediate member ( 3 ), characterized in that, from the cam via a contact surface ( 3g ) acted upon intermediate member ( 3 ) by a toggle ( 3 ) is formed, which on the one hand its hinge axis C3 with at least one guide rocker ( 3a ) and on the other hand its joint axis C3 with at least one control latch ( 3b ) and the guide rocker ( 3a ) with its hinge axis C3 facing away from the end with an adjustment ( 2 ) is pivotally connected, wherein the position of the pivotally movable connection by the adjusting means ( 2 ) is changeable and the control latch ( 3b ) at its the hinge axis C3 opposite end via a support roller ( 3h ) with a center C3a or via a circular arc-shaped sliding surface with a center C3a on a housing-fixed slide track ( 4a ) is supported and the slide track ( 4a ) is designed as a circular arc, which during the valve latch concentric with the center of rotation C5 of the roller of the valve actuator ( 5 ) is arranged and the roller of the valve actuator ( 5 ) with a control cam ( 3f ) of the control latch ( 3b ) is in drive connection, which control cam ( 3f ) from a valve latch section ( 3c ), which describes a radius contour around the center C3a, via a starting ramp deviating from the radius contour (( 3d ) in a lifting section ( 3e ) passes over. Valve gear according to claim 1, characterized in that - the adjusting means ( 2 ) by a, about a fixed axis C2 rotatable eccentric shaft ( 2 ) is formed, wherein the guide rocker ( 3a ) is mounted to pivot or roll around the center of the eccentric and the eccentric shaft ( 2 ) is optionally electromechanically or hydraulically rotated, or - the adjusting means is formed by a linearly guided ram, which at a free end via a joint with a guide rocker ( 3a ) is operatively connected, wherein the plunger selectively hydraulically or mechanically actuated (eg piston - cylinder, movement thread or racks - toothed shaft connection) is displaceable in its guide, in particular for each cylinder, a single, independently of the other cylinders, adjustable plunger can be provided. Valve gear according to claim 1 and 2 characterized in that, - located on the slide tracks ( 4a ) supporting support rollers ( 3h ) on the control latches ( 3b ) is roller-mounted on a bearing pin, wherein for each control pawl ( 3b ) one support roller each ( 3h ) is arranged axially in the Hubventilebene, or - a common roller bearing support roller on a common bearing pin axially between two control pawls ( 3b ) is arranged in the cylinder plane, which is located on a common, arranged axially in the cylinder plane slide track ( 4a ) is supported. Valve gear according to claim 1 to 3, characterized in that - two acted upon by a cam attack surfaces ( 3g ) on the knee lever ( 3 ) by a respective roller bearing roller ( 3g ) are formed, which are mounted concentrically to the articulated connection C3, wherein each a roller ( 3g ) in the middle of a control latch ( 3b ) is arranged axially in the Hubventilebene, or - one, acted upon by a cam attack surface ( 3g ) on the knee lever ( 3 ) is formed by a single roller, which is mounted concentrically to the articulated connection C3, wherein the roller centrally within the guide rocker ( 3a ) is arranged axially in the cylinder plane, or - two acted upon by a cam attack surfaces ( 3g ) on the knee lever ( 3 ) by a respective molded sliding surface on each control pawl ( 3b ) are formed, which are arranged axially in the Hubventilebene, or - one, acted upon by a cam attack surface ( 3g ) on the knee lever ( 3 ) by a molded sliding surface on the guide rocker ( 3a ) is formed, which is arranged axially in the cylinder plane, Valve gear according to claim 1 to 4, characterized in that, - in two parallel actuated globe valves ( 7 ) a common guide rocker ( 3a ) and / or - a common control pawl ( 3b ) is provided, which preferably acts on a so-called fork rocker arm. Valve gear according to claim 1 to 5 characterized in that, each slide track ( 4a ) on a, preferably made of steel, one-piece block block ( 4 ) is provided, which preferably extends over a plurality of cylinders, wherein the sliding block ( 4 ) is preferably oriented at one, extending over the cylinder head, stop surface or groove in its position and bolted to the cylinder head. Valve gear according to claim 1 to 6, characterized in that, between at least part of the toggle lever ( 3 ) and the cylinder head housing at least one preloaded Lost Motion spring ( 8th ) is arranged, which by a linearly guided compression spring ( 8th ) or may be formed by a torsion leg spring or by a tension spring. Valve gear according to claim 1 to 7 characterized in that, - in two parallel actuated globe valves ( 7 ) a single, arranged in the cylinder plane guide rocker ( 3a ) is rotatably mounted on the connecting bolt with the axle center C3 via a rolling or sliding bearing, wherein two axially arranged in the Hubventilebenen control pawls ( 3b ) are non-rotatably joined with the connecting bolt, or - in the case of two parallel actuated lifting valves ( 7 ) a single, arranged in the cylinder plane guide rocker ( 3a ) is non-rotatably joined with the connecting bolt with the axis center C3, wherein two axially arranged in the Hubventilebenen control pawls ( 3b ) are rotatably mounted on the connecting bolt with the axle center C3 via a rolling or sliding bearing.