EP2520773A2 - Combustion engine with at least one combustion chamber - Google Patents

Abstract

The internal combustion engine has a combustion chamber (1), from which exhaust gas is discharged by the discharge valves (2,2'). An engine braking device is provided with a hydraulic valve-control unit (3), which is integrated into a connection mechanism (5) for connecting the discharge valves with a cam shaft (4) and holds the discharge valves in an intermediate open position during actuation of the engine braking device. A hydraulic valve clearance compensation mechanism (7) is provided for the discharge valves. An independent claim is included for a method for operating an internal combustion engine.

Description

The invention relates to an internal combustion engine having at least one combustion chamber, from which by means of at least one exhaust valve exhaust is discharged, comprising an engine brake device with a hydraulic auxiliary valve control unit, which is integrated into the exhaust valve with a camshaft connecting link mechanism and the exhaust valve when the engine brake device in an intermediate-open position and a hydraulic valve clearance compensation mechanism for the exhaust valve, wherein the link mechanism comprises at least one rocker arm and an intermediate member disposed between the rocker arm and the exhaust valve and the hydraulic auxiliary valve control unit of the engine braking device comprises a first piston-cylinder unit for temporary intermediate opening of an exhaust valve and the hydraulic lash adjuster mechanism comprises a second piston-cylinder unit for counteracting valve lash.

Out US 2010/319657 A1 is known a method and a system with an EVB (Exhaust Valve Brake), in which the braking energy of the engine is achieved by the combination of a motor dust brake and a decompression brake. For this sees the US 2010/0319657 A1 in that two exhaust valves are controlled on a valve bridge, wherein one of the exhaust valves is mounted on the valve bridge by a piston-cylinder unit movable and controllable. This first piston-cylinder unit in the valve bridge ensures the feasibility and holding an open position of the linearly displaceable exhaust valve of the valve bridge and thus the possibility of braking.

Further, the valve bridge comprises a second piston-cylinder unit, which serves as a connecting means to the valve-side leg of the rocker arm, wherein on the upper side of this rocker arm leg of the rocker arm is biased by a spring. In addition, the camshaft is provided with a larger main exhaust cam and a smaller compression reduction cam. With each revolution of the camshaft, regardless of whether a braking operation has been initiated, the rocker arm responds to the two cams of the camshaft. Through an oil guide channel extending from the center of the rocker arm via the connecting elements, to the second piston-cylinder unit and from this to the first piston-cylinder unit, the system is applied during the braking phase with an oil pressure, which is controlled with the the channel connected elements acts. By way of an outlet opening of the valve bridge, which is closed in phases by an anvil, the oil trapped in the valve bridge or the oil pressure can escape or be decomposed at certain times (when passing through the large cam).

A disadvantage of this system is that on the one hand an active activation namely an oil pressure loading is required to open the exhaust valve for the braking effect of the engine and keep it open. Basically, the construction of an oil pressure within the rocker arm, the valve bridge and the parts connecting them is problematic because in the course of using this system, the tolerances and in particular the tightness of the aforementioned elements can vary greatly, which directly affects the reliability of the pressure build-up and thus can affect the controllability of the outlet opening. Furthermore, it is disadvantageous that the entire system always passes through both cams. The movement of the compression reduction cam in the non-braking state represents an unnecessary expenditure of energy and increases the wear of the entire system.

Another disadvantage is the fact that in case of a defect of the necessary for the valve clearance compensation piston-cylinder unit as well as the feasibility of the first piston-cylinder unit is directly affected, since the oil supply passage in the manner of a series circuit passes through several elements.

The invention has the object of providing an internal combustion engine with the features of the preamble of claim 1 and a method of operating an internal combustion engine according to the preamble of claim 15 such that in a simple and reliable way a valve clearance compensation and at the same time a combined engine dust and decompression brake ( EVB) is executable. It is another object of the invention to make the system such that it is easy to manufacture, is subject to low wear, the executed movements of the elements are low and have a low frictional resistance. A further object of the invention is to enable a passively controlled EVB which manages without an actively acting electronic / electrical or hydraulic control line.

This object is solved by the features of claims 1 and 15. Advantageous developments of the invention will become apparent from the dependent claims 2 to 14.

As the core of the invention, it is considered that the first piston-cylinder unit is arranged in or on the intermediate element and the second piston-cylinder unit in or on the rocker arm. The fact that the first and the second piston-cylinder unit are arranged in or on two separate elements of the connecting mechanism, it is easily possible to achieve a delay in the response of the two piston-cylinder units to each other. Another core of the invention is to take advantage of this delay of the response of the two piston-cylinder units to each other and to take into account in the interpretation that substantially minimizes undesirable effects of a piston-cylinder unit to the other piston-cylinder unit and / or completely excluded.

Since the intermediate element, usually including, inter alia, a valve bridge is not firmly connected to the rocker arm and a gap could result if the valves would perform a fast to the combustion chamber directed movement. Such a gap would lead to an albeit small proportion of movement of the rocker arm is possible without direct influence on the intermediate element. During this rate of motion inertia forces may act as a drag and / or acceleration retarding effect on the rocker arm. When a force acts on the rocker arm, this forces a rotational movement, this movement is carried out only with delay or with a delayed acceleration, since the mass of the rocker arm acts. For example, this effect can be used positively in the case of a valve jump, since the restoring force of the hydraulic valve play compensation (from the second piston-cylinder unit) can therefore only have a limited effect on a possible undesired adjustment movement of the rocker arm in the direction of valves. This can lead to the introduction of force acting on the rocker arm and its movement / acceleration so late that the second piston-cylinder unit arranged on the rocker arm does not react directly and thus delayed and thus unwanted movement and / or acceleration of the second piston Cylinder unit prevented or thereby at least can be minimized so that only a negligible impact on the overall system.

According to a preferred embodiment, the first and the second piston-cylinder unit for oil supply are connected to a common oil source, wherein the first and the second piston-cylinder unit are each connected to the oil source without the interposition of the other. The valve drive or the connection mechanism is fed, for example, by an oil feed present at the bearing of the rocker arm. The provided there with a substantially constant pressure oil is passed through oil passages both to the first and the second piston-cylinder unit and to bearings of movably mounted parts. In this structural measure has the advantage that the first and the second piston-cylinder unit are independently pressurized with oil pressure, so that in case of failure of one of the two piston-cylinder units each other in their function and / or in your control not being affected.

The decoupling of leading to the first and second piston-cylinder unit oil channels also supports the delayed, decoupled and thus more independent function of each piston-cylinder unit.

In a particularly preferred embodiment, the rocker arm has at least two legs enclosing an angle. Here, in a first variant, the second piston-cylinder unit in or on the camshaft facing leg of the Rocker be arranged. In an alternative variant, the second piston-cylinder unit arranged in or on one limb of the rocker arm is arranged between a rocker arm bearing and the intermediate element or the valve bridge, preferably with the interposition of a further separately movable rocker arm element.

The former variant is characterized by the fact that the arrangement of the second piston-cylinder unit on the opposite side of the valve bridge leg of the rocker arm, the effect of inertia on the movement of the rocker arm is amplified. With the second variant, a series connection of the oil supply of the first and second piston-cylinder unit can be realized. Also in embodiments in which the rocker arm is formed of a plurality of mutually movable parts, an arrangement of the second piston-cylinder unit between the rocker arm bearing and the intermediate elements or on the intermediate element (eg., The valve bridge) associated side starting from the rocker arm be beneficial.

The intermediate element may comprise, as an essential component, a valve bridge which connects at least two exhaust valves to one another. Furthermore, the intermediate element may also comprise connecting links between the rocker arm and the outlet valve. In the following, reference is made to embodiments in which the intermediate element is designed as a valve bridge.

In the EVB systems, a distinction can be made between active and passive systems wherein the active systems for shifting the exhaust valve to an intermediate open position either use direct electronic / electrical control of an exhaust valve or initiate it via a control circuit operating at a defined controllable oil pressure. The passive systems to this effect are characterized by the fact that the intermediate opened position of the exhaust valve initiated by an exhaust gas backflow stagnated in the exhaust duct, or that the exhaust valve is stopped in its closing movement in an intermediate position. In this case, a flap in the exhaust duct is closed to achieve the braking effect of the engine, which builds up from there exhaust gas builds up a back pressure, which is the closing of the linearly movably mounted in the valve bridge Counteracts exhaust valve. The blocking effect of the first piston-cylinder unit keeps the outlet valve open.

Another significant advantage in the embodiment underlying the inventive concept can be achieved in that the rocker arm is constructed in several parts and comprises a base body and a carrier body, wherein the carrier body is movably mounted relative to the base body and the relative mobility of the base body and carrier body through the second piston-cylinder unit can be influenced. As a result of the oil pressure being applied to the second piston-cylinder unit, a biasing force can act between the two levers, so that a hydraulic valve clearance compensation (HVA) can be carried out by the relative movement of the base body and carrier body. Alternatively or additionally, a correspondingly biased spring can apply the restoring force.

Preferably, the second piston-cylinder unit is designed in the manner of a one-way valve and executed with a biasing action relative to the carrier body to the camshaft with the second piston-cylinder unit ensures a substantially rigid connection between the rocker arm and the camshaft in a locked phase. Preferably, a deflection is carried out during a readjustment phase. The second piston-cylinder unit forms an integral part of the hydraulic valve clearance compensation and ensures that in the event that between the contact region of the support body (eg a roller) and the camshaft resulting due to wear or other circumstances gap Adjustment of the second piston-cylinder unit reliably remains closed, or does not form.

Preferably, the method according to the invention is applied to an overhead camshaft engine.

However, despite hydraulic valve clearance compensation, the basic function of the rocker arm to be ensured, after which the rocker arm undergoes a defined tilting movement when passing through the cam, for this purpose, the rocker arm in a certain rigid property in itself, which is carried out at least during the lock phase. Despite the almost rigid connection of the base and Trägerköpers starting from the second piston-cylinder unit, a slight deflection of the second piston-cylinder unit is executed or approved accepting the cam when passing through the cam. It is important to note here that in the interpretation of reacting to the tilting movement of the rocker arm components this slight deflection of the second piston-cylinder unit is considered when passing through the cam. The slight deflection in the passage of the cam and the then performed recovery of the second piston-cylinder unit from a arranged in the second piston-cylinder unit return spring and / or by the voltage applied to the second piston-cylinder unit oil pressure allows one Self-balancing of the system so that, if necessary, too strong adjustment by the second piston-cylinder unit to avoid a gap this can be returned to a "normal" again after passing through the cam of the camshaft. This avoids increased stresses in the connection mechanism.

It is further proposed to align the axis of rotation of a rotatable support body concentric with the axis of rotation of the rocker arm. The fact that the two bearing points coincide will require fewer bearing elements and allow a compact design.

Furthermore, it is advantageous if a contacting with the camshaft contact element is arranged on the carrier body or movably mounted on the carrier body, wherein preferably the contact element is designed as a rotatably mounted on the carrier body roller. The carrier body thus acts as a carrier of the contact element designed as a roller and allows movement of the contact element in response to the movement of the camshaft.

The carrier body is in turn movably mounted on the main body or parallel to this at, for example, a rocker shaft. If the carrier body is movably mounted on the base body, this can be realized either by a rotary bearing which ensures a rotational movement of the carrier body relative to the base body or by a linear bearing which ensures a linear movement of the carrier body relative to the base body become. In the case of a rotatably mounted on the base body support body, it is advantageous if the longitudinal axis of the second piston-cylinder unit with an auxiliary line extending from a point of retracted end position of the second piston-cylinder unit to the center of the axis of rotation of the camshaft and / or spans to the center of the axis of rotation of a rotatably mounted contact element, encloses an angle of 45 ° to - 45 °. In the case of a linearly mounted carrier body, it is advantageous if the longitudinal axis of the second piston-cylinder unit to the longitudinal axis of the linear movement of the support body forms an angle of 45 ° to - 45 ° or aligned parallel thereto. In particular, it is advantageous if the angular range between 20 ° to -20 °, particularly preferably between 10 ° to -10 °, both for the rotatable and for the linearly displaceable support body. The closer the angle approaches to 0 ° or to the parallel alignment of the two longitudinal axes, the more favorable the efficiency of the introduction of force of the second piston-cylinder unit on the support element, so that a lower oil pressure to perform the defined restoring force is needed.

The first and the second piston-cylinder unit are preferably each provided with a biased by a spring piston, a pressure chamber and a pressure chamber at least in phases occlusive locking element. The blocking element and the pressure chamber make it possible for these elements to be used as blocking means by the oil temporarily trapped in the pressure chamber. Due to the blocking function of the second piston-cylinder unit, the mobility of the carrier to the main body can be largely inhibited. By the blocking function of the first piston-cylinder unit, a holding function of the exhaust valve in an intermediate open position executable.

The pressure chamber of the first piston-cylinder unit comprises a leading to the outside of the pressure chamber of the intermediate element oil passage which is phase-locked by a counter-holder substantially oil-tight. The closing function of the counter-holder with regard to the oil passage of the pressure chamber of the first piston-cylinder unit leading from the intermediate element (eg the valve bridge) is active when the rocker arm runs on the base circle of the cam and thus the valve bridge remains in its closed valve position , Now, if the rocker arm, starting from the passage of the cam a Performs tilting movement, thereby the valve bridge is pressed down, the counter-holder as relative to the pivot point to the rocker arm fixed element remains in place, so that the leading from the pressure chamber of the first piston-cylinder unit oil passage is released to the outside of the valve bridge, so that the In the pressure chamber prevailing oil pressure is removed and the blocking function of the first piston-cylinder unit is canceled, and thus the exhaust valve actuated in the first piston-cylinder unit or connected is moved back into its closing end position by the spring force of the valve springs.

In principle, the system according to the invention can be applied to both active and passive EVBs. However, a particularly advantageous embodiment is achieved in that the inventive idea underlying the main claim is applied to a passive EVB and the engine braking effect is achieved by keeping open an exhaust valve and / or not by an additional operating exclusively for the braking effect valve.

The device according to the invention is also based on a method which is characterized essentially by the fact that the internal combustion engine is provided with at least one two-part rocker arm for operating an internal combustion engine with a hydraulic valve lash adjuster and a combined engine stall and decompression brake, which comprises a carrier body and a base body perform in the case of the valve clearance compensation relative movement to each other, wherein in a short-term movement of the valve and / or the intermediate element, the second piston-cylinder unit due to their arrangement in or on the rocker arm and / or the inertia of the rocker arm an insignificant or no movement of the carrier body is performed relative to the main body.

Fig. 1:

eine schematische Schnittdarstellung eines Teiles einer Brennkraftmaschine, die mit einer Motorbremseinrichtung und einem hydraulischen Ventilspielausgleichsmechanismus ausgestattet ist;

Fig. 2:

eine schematische Schnittdarstellung gemäß Detail A aus Figur 1;

Fig. 3:

eine vereinfachte schematische Darstellung wesentlicher Elemente der Brennkraftmaschine mit geschlossenen Ventilen und Kipphebelrolle auf Nockengrundkreis;

Fig. 4:

eine schematische Darstellung gemäß Figur 3, wobei die Kipphebelrolle auf dem Nocken läuft und die Ventile in Offenstellung positioniert sind;

Fig. 5:

eine schematische Darstellung gemäß Figur 3, wobei die Kipphebelrolle auf dem Nockengrundkreis läuft und ein Auslassventil in eine zwischengeöffnete Stellung angeordnet ist (Bremsbetrieb);

Fig. 6:

eine schematische Darstellung gemäß Figur 3, wobei die Kipphebelrolle auf dem Nocken der Nockenwelle läuft und die beiden Auslassventile in der geöffneten Stellung angeordnet sind;

Fig. 7:

eine schematische Darstellung einer alternativen Ausführungsform des Verbindungsmechanismus zwischen Nockenwelle und Auslassventile;

Fig. 8:

eine schematische Darstellung einer weiteren alternativen Ausführungsform wobei die zweite Kolben-Zylinder-Einheit zwischen Nockenwelle und Auslassventil angeordnet ist;

Fig. 9:

eine schematische Darstellung gemäß Figur 3 die Ventile einen Ventilsprung ausführen;

Fig. 10:

eine schematische Detaildarstellung der zweiten Kolben-Zylinder-Einheit.

The invention is explained in more detail with reference to embodiments in drawing figures. These show:

Fig. 1:

a schematic sectional view of a part of an internal combustion engine, which is equipped with an engine brake device and a hydraulic valve clearance compensation mechanism;

Fig. 2:

a schematic sectional view according to detail A from FIG. 1 ;

3:

a simplified schematic representation of essential elements of the internal combustion engine with closed valves and rocker roller on cam base circle;

4:

a schematic representation according to FIG. 3 wherein the rocker arm roller is running on the cam and the valves are positioned in the open position;

Fig. 5:

a schematic representation according to FIG. 3 wherein the rocker arm roller is running on the cam base circle and an exhaust valve is arranged in an intermediate open position (braking operation);

Fig. 6:

a schematic representation according to FIG. 3 wherein the rocker roller is running on the cam of the camshaft and the two exhaust valves are arranged in the open position;

Fig. 7:

a schematic representation of an alternative embodiment of the connection mechanism between the camshaft and exhaust valves;

Fig. 8:

a schematic representation of another alternative embodiment wherein the second piston-cylinder unit between the camshaft and exhaust valve is arranged;

Fig. 9:

a schematic representation according to FIG. 3 the valves make a valve jump;

Fig. 10:

a schematic detail of the second piston-cylinder unit.

Drawing figure 1 shows the essential elements of the invention. An internal combustion engine is provided with at least one combustion chamber 1, from which exhaust gas can be discharged by means of at least one exhaust valve 2, 2 ', wherein the internal combustion engine is provided with an engine brake device with a hydraulic additional valve control unit 3. The auxiliary valve control unit 3 is integrated into a connecting mechanism 5 connecting the exhaust valve 2, 2 'to a camshaft 4, the exhaust valve 2 being held in an intermediate open position Z when the engine braking device is actuated. The valves 2, 2 'are moved by the reaction of the rocker arm 6 to the position of the camshaft 4 between a closed position S and an open position O back and forth. Only one of the exhaust valves 2, 2 'namely exhaust valve 2 can be kept temporarily or during a braking phase by the additional valve control unit 3 in the case of a braking operation in an intermediate open position Z.

Furthermore, the internal combustion engine comprises a hydraulic valve clearance compensation mechanism 7 by which occurring in the course of wear of individual elements of the connecting mechanism 5 wear and thus a game within the system by adjusting individual elements is avoided. The connecting mechanism 5 further comprises a rocker arm 6 and an intermediate element 8 arranged between the rocker arm 6 and the outlet valve 2, 2 '. The intermediate element 8 is designed in the illustrated embodiment as a valve bridge 9 which couples two exhaust valves 2, 2' to one another tilting lever side adjustably mounted adjusting screw 10 is in contact. The adjusting screw 10 is connected via a coupling element 29 with the valve bridge 9, the coupling element 29 may be an integral part of the intermediate element 8 or an attached component of the intermediate element 8. The coupling element 29 is in the illustrated embodiment on the valve bridge 9 and can move away from this.

By the adjusting screw 10, a tilting movement of the rocker arm 6 is transmitted to the valve bridge 9 and thus to the exhaust valves 2, 2 '. As a result of this movement, activation of the outlet valves 2, 2 'and their defined movement from a closed position S to an open position O and back is achieved. The two valves 2, 2 'are biased by valve springs (not shown) in their closed position S, so that also a return movement after moving back the rocker arm is executable. To realize the engine braking device, the hydraulic additional valve control unit 3 provides a first piston-cylinder unit 11. The hydraulic valve clearance compensation mechanism 7 comprises a second piston-cylinder unit 12 which counteracts the occurrence of a valve clearance.

The first piston-cylinder unit 11 is arranged in the illustrated embodiment in the valve bridge 9 and the second piston-cylinder unit 12 in the rocker arm 6.

In the FIGS. 1 . 2 . 3 . 5 . 7 . 8th and 9 the connection mechanism 5 is always aligned on the base circle of the camshaft 4 and thus in its normal position G. In the FIGS. 4 and 6 the connection mechanism 5 is moved out of the basic position G by the cam 13 of the camshaft 4 into a position which brings the valves 2, 2 'into the open position O.

The first and the second piston-cylinder unit 11, 12 is connected to the oil supply to a common oil source here in the storage area 14 of the rocker arm 6, wherein the first and second piston-cylinder unit 11, 12 respectively without interposition of the other piston Cylinder unit 11, 12 is connected to the oil source. Starting from the bearing 14 of the rocker arm 6 oil is passed through an axial bore 15 to the center of the bearing 14 and from there via channel sections 16, 16 ', 16 "within the bearing 14 to the camshaft side of the rocker arm 6, to the valve bridge side of the rocker arm. 6 and to lubrication regions 17 for lubricating the rotational movement of the rocker arm 6 relative to the bearing 14. The channel section 16 merges into the oil passages 18, 18 'which guide the oil to bearings or the axes of rotation 19, 20 of a carrier body 21 and a roller 22, respectively The channel portion 18 'also disposed in the rocker arm 6 directs the oil to the second piston-cylinder unit 12. The channel portion 16 guides the oil through a passage portion 23 to the adjusting screw 10 within which an axial oil guide bore (not shown) is located in turn, the oil leads to the valve bridge 9 and there in an arranged within the valve bridge 9 oil passage 24 to a pressure chamber 25 of the ers th piston-cylinder unit 11 leads.

The rocker arm 6 is preferably provided with two legs 26, 26 'enclosing an angle α, the second piston-cylinder unit 12 being arranged in the leg 26 of the rocker arm 6 facing the camshaft 4, cf. FIG. 2 , In an alternative embodiment shown in FIG. 7, the second piston-cylinder unit 12 is arranged in the leg 26 'of the rocker arm 6, wherein the second piston-cylinder unit 12 is arranged in the region between a rocker arm bearing 14 and the valve bridge 9.

The rocker arm 6 is constructed in several parts in the illustrated embodiment and comprises a base body 27 and a support body 21, wherein the support body 21 is rotatably mounted relative to the base body 27, wherein the relative mobility (arrow R) of the base body 27 and support body 21 through the second piston-cylinder unit 12 can be influenced. As the main body 27, the element of the rocker arm 6 is defined, which is mechanically closer to the valve bridge 9 and the intermediate element 8. The carrier element 21 forms the carrier for the contact element 28 which is in contact with the camshaft 4. The contact element 28 may be a slider, compare FIG. 7 or include a roller 22. The axis of rotation 29 of the support body 21 may be aligned concentrically with the axis of rotation 14 of the main body 27 of the rocker arm 6 according to the drawing figures 7 and 8.

The support body 21 is thus rotatably arranged on the main body 27 via the rotation axis 19 according to the drawing figures 1 to 6, wherein the rotational movement R of the support body 21 by action of the second piston-cylinder unit 12 on the one hand and on the other hand by the contact via the contact element 28 and / or the roller 22 is affected on the camshaft 4. When the camshaft 4 is further rotated out of the base circle, the roller 22 drives on the cam 13, the second piston-cylinder unit 12 behaves substantially - except for a slight deflection and rebound - rigid and initiates the movement of the cam 13 the rocker arm 6, so that it performs a rotational movement, which in turn acts on the valve bridge 9 via the adjusting screw 10 and this displaced in the direction of the combustion chamber 1 and thus the valves 2, 2 'in an open position O spends. By this essentially a blocking effect performing property of the second piston-cylinder unit 12, the usual function of Rocker arms 6 are ensured. The substantially rigid property of the second piston-cylinder unit 12 can be achieved by behaving essentially in the manner of a one-way valve.

As shown in particular in Figure 1, it is advantageous if the longitudinal axis 31 of the second piston-cylinder unit 12 with a straight auxiliary line 32, the point of the retracted end position (cross-sectional center of the piston, in FIG. 1 marked "x") of the second piston-cylinder unit 12 is constructed with the rotational axis 20 of the pivot bearing, an angle β 45 ° to -45 °, including in particular an angle β of 10 ° to -10 °.

The structure of the first and / or the second piston-cylinder unit 11, 12 respectively provides a preferably by a spring 41, 45 in the extended position biased piston 40, 44, a pressure chamber 25, 47 and a pressure chamber 25, 47 at least phasing blocking element 42, 46 before. Thus, a filled with oil pressure chamber 25, 47 and with simultaneous closure of the pressure chamber 25, 47 by the blocking element 42, 46 a blocking of the movement of the first and / or second piston / cylinder unit 11, 12 are executed.

The arranged in the valve bridge 9 pressure chamber 25 of the first piston-cylinder unit 11 also provides a leading to the outside of the pressure chamber 25 oil passage 33, which is in phases closed by the anvil 34. This shutter stops at least as long as the valve bridge 9 remains in its basic position GS. When the roller 22 is running on the cam 13 of the camshaft 4, the valve bridge 9 is moved downward from its basic position GS by the tilting movement of the rocker arm 6, so that the positionally fixed counterholder 34 releases the oil passage 33 and thus the pressure chamber 25 and pushes out the oil trapped therein can be.

How out FIG. 10 can be seen, the second piston-cylinder unit 12 comprises a disc 48 on which a cylindrical support means 49 having a through hole centrally in the bottom surface, is attached. Between the piston 44 and support means 49, a pressure chamber 47 is formed, which via the through hole with an anteroom connected is. The support means 49 is partially surrounded by an inner region of the piston 44. A step in the interlocking area serves as Endlagenbegrenzer the movement of the piston 44 relative to the support means 49. The through hole is closed in phases with a ball 51, wherein a spring 52 biases the ball 51 in its closed position, this spring is supported on a 52 Cage 53 off. During the compression of the second piston-cylinder unit reach small amounts of oil in the pressure chamber 47 through the gap 50 of the piston 44 and support means 49 to the vent passage 37th

According to the second piston-cylinder unit 12 and the bearing 19 of the support body 21 to the base body 27 is arranged and designed such that in short-term movements of the valves 2, 2 'influenced by the second piston-cylinder unit 12 movement R of the Carrier body 21 relative to the base body 27 to a negligible extent or not executed, preferably this is based to an insignificant extent or not performed movement substantially on the inertia of the rocker arm. 6

In particular, in the case of a valve jump which describes a short-term movement 35 of the valves 2, 2 ', this inertia is essential, cf. FIG. 9 , In FIG. 9 the valves 2, 2 'are shown schematically with a distance 43, 43' from the valve bridge 9. For example, when the valves 2, 2 'are acted upon by the exhaust gas jammed back from an exhaust gas flap (not shown) in the exhaust pipe, a force acting on the valves 2, 2' initiates a sudden movement 35 of the valves 2, 2 '. Since the valves 2, 2 'are moved away from the valve bridge 9 due to this jump movement, the valve bridge 9 is in a quasi "floating state" because the support to the valves 2, 2' is missing. In this situation, the valve bridge could also - like the valves 2, 2 '- move towards the combustion chamber 1 and from the basic position GS away. This would cause the anvil 34 opens the oil passage 33 and can build up no oil pressure in the pressure chamber 25 and finally it would come to a blocking effect of the valve 2 in its intermediate open position.

To make matters worse, that the second piston-cylinder unit 12 by its bias of the support body 21 to the camshaft 4 causes the biasing force the rocker arm 6 in the direction (in FIG. 9 : clockwise) to the valve side and the valve bridge 9 would actively push away from its home position GS. This influence of the second piston-cylinder unit 12 is not desired. Therefore, the inertia of the rocker arm 6, in particular that of the main body 27 can be used to the effect that the effect of the second piston-cylinder unit 12 on the acceleration of the rocker arm 6, in particular of the main body 27, so "delayed" is performed that it is not comes to a "pushing" of the valve bridge through the second piston-cylinder unit 12 or this happens only in an insubstantial for the overall course dimensions. Since during the valve jump, the first piston-cylinder unit 11 extends, which fills thereby increasing pressure chamber volume with oil from the oil passage 23, 24, an oil pressure in the pressure chamber 25, which gives the valve bridge 9 a "stop" and this forms in the Basic position GS and thus against the anvil 34 presses.

The distance 43 or the path of the valve 2 from the valve bridge 9 should be ensured by the possible, held out path of the piston 40 within the cylinder of the first piston-cylinder unit 11. By the spring 41, a quick reaction of the first piston-cylinder unit 11 is achieved, which in turn allows a rapid filling of the enlarged by the piston movement pressure chamber 25. Thus, the first piston-cylinder unit 11 reacts with the result of the blocking effect by filling the pressure chamber 25 and the lock by the blocking element 42 faster than the second piston-cylinder unit 12 with the Vorspannungsweitergabe or force application to the valve bridge 9 and thus with the movement of the valve bridge 9 to the combustion chamber 1 out.

Alternatively and / or in addition to the consideration of the mass of the rocker arm 6 and the associated delayed acceleration of the rocker arm 6, it may be provided, the bearing area of the axis of rotation 19 of the support member 21 relative to the base body 27 and / or the storage of the rocker arm 6 at its Kipphebelellager 14 form such that an inertia is forced by the increased static friction the rocker arm 6 and its acceleration capability, so that the second piston-cylinder unit 12 can not or only insignificantly close a (short-term) distance 43, 43 'between the valve bridge 9 and the valves 2, 2' by moving the valve bridge 9. In the course of the valve jump, there may be an uneven and or non-synchronous movement of the valves 2, 2 'relative to the valve bridge 9. Also, in this case, the valve bridge could briefly move in an inclined position.

Further, go out FIG. 2 that the camshaft 4 facing the first leg 26 of the rocker arm 6 and the exhaust valve 2, 2 'facing second leg 26' of the rocker arm 6 are each provided with at least one oil guide channel 18 ', 23 wherein the oil guide channels 18', 23 with the Oil source (here the bore 15) are connected and the oil, starting from the arranged in the region of the Kipphebellagers 14 oil source via the oil guide channels 18 ', 23 to the first and second piston-cylinder unit 11, 12 can be fed. In the illustrated embodiment, a further oil guide channel 18 is additionally arranged in the first leg 26, which passes the oil to the storage area 19 of the carrier body 21 and channel sections in the carrier body 21 via this to the storage area 20 of the contact element 28. At the oil guide channel 18 'and / or at the second piston-cylinder unit 12, a vent channel 37 is provided, which emits a small amount of oil, for example, in the case of compression of the second piston-cylinder unit 12 to the environment of the rocker arm 6 , Additionally or alternatively, air can escape through the channel 37 of the rocker arm 6.

The above-described arrangement of the first and second piston-cylinder unit 11, 12 according to the invention is particularly advantageous for overhead camshaft engines 4.

LIST OF REFERENCE NUMBERS

1

combustion chamber

2, 2 '

outlet valve

3

Valve additional control unit

4

camshaft

5

joint mechanism

6

rocker arm

7

Valve play compensation mechanism

8th

intermediate element

9

valve bridge

10

adjusting

11

first piston-cylinder unit

12

second piston-cylinder unit

13

Cam v. 4

14

Warehouse v. 6

15

drilling

16, 16 ', 16 "

channel section

17

lubrication region

18, 18 '

channel section

19

Rotation axis v. 21

20

Rotation axis v. 22

21

Carrier body v. 22, 28

22

role

23

Canal section v. 26

24

oil passage

25

Pressure chamber v. 11

26, 26 '

Thighs v. 6

27

Basic body v. 6

28

contact element

29

coupling element

30

31

Longitudinal axis v. 12

32

ledger line

33

Oil channel v. 8th

34

backstop

35

Move

36

exhaust duct

37

vent channel

40

Piston v. 11

41

Federv.11

42

Blocking element v. 11

43, 43 '

Distance between 2, 2 'and 9

44

Piston v. 12

45

Spring v. 12

46

Blocking element v. 12

47

Pressure chamber v. 12

48

disc

49

proppant

50

gap

51

Ball v. 46

52

Spring v. 46

53

Cage v. 46

α

Angle between 26 and 26 '

β

Angle between 31 and 32

R

Movement between 21 and 27

S

Closed position v. 2, 2 '

O

Open position v. 2, 2 '

Z

Intermediate disclosure v. 2

G

Initial position. v. 6

GS

Basic position v. 9

Claims (15)

Internal combustion engine having at least one combustion chamber (1) from which exhaust gas can be discharged by means of at least one exhaust valve (2, 2 '), comprising an engine brake device with a hydraulic auxiliary valve control unit (3) which is connected to the exhaust valve (2) with a camshaft (3). 4) connecting the connecting mechanism (5) is integrated and holds the exhaust valve (2) with the engine brake device in an intermediate open position (Z), and a hydraulic valve clearance compensation mechanism (7) for the exhaust valve (2, 2 ') wherein the connecting mechanism (5) at least one rocker arm (6) and an intermediate element (8) arranged between the rocker arm (6) and the outlet valve (2, 2 ') and the hydraulic auxiliary valve control unit (3) of the engine brake device comprises a first piston-cylinder unit (11) for the temporary intermediate opening of an exhaust valve (2) and the hydraulic valve clearance compensation mechanism (7) comprises a second piston-cylinder Einhei t (12) for counteracting a valve clearance comprises, characterized in that the first piston-cylinder unit (11) in or on the intermediate element (8) and the second piston-cylinder unit (12) in or on the rocker arm (6) is. Internal combustion engine according to claim 1, characterized in that the first and second piston-cylinder unit (11, 12) are connected to the oil supply to a common oil source and the first and second piston-cylinder unit (11, 12) respectively without interposition of each other piston-cylinder unit (11, 12) are connected to the oil source. Internal combustion engine according to claim 1 or 2, characterized in that the rocker arm (6) comprises at least two legs (26, 26 ') enclosing an angle α and - The second piston-cylinder unit (12) in or on the camshaft (4) facing legs (26) of the rocker arm (6) is arranged or - The arranged in or on a leg (26) of the rocker arm (6) second piston-cylinder unit (12) between a rocker arm bearing (14) and the intermediate element (8) is arranged. Internal combustion engine according to one of claims 1 to 3, characterized in that the intermediate element (8) is designed as a valve bridge (9) which connects at least two exhaust valves (2, 2 ') with each other. Internal combustion engine according to one of the preceding claims, characterized in that the rocker arm (6) is constructed in several parts and a base body (27) and a carrier body (21) wherein the carrier body (21) relative to the base body (27) is movably mounted and the Relative mobility (R) of the base body (27) and carrier body (21) by the second piston-cylinder unit (12) can be influenced. Internal combustion engine according to claim 5, characterized in that the axis of rotation (19) of the Trägerköpers (21) concentric with the axis of rotation (20) of the base body (27) of the rocker arm (6) is aligned. Internal combustion engine according to claim 5 or 6, characterized in that the second piston-cylinder unit (12) carries out a bias of the carrier body (21) to the camshaft (4) out with the second piston-cylinder unit (12) in a locking phase ensures a substantially rigid connection between the rocker arm (6) and the camshaft (4) wherein preferably during a Nachstellphase a deflection is executable. Internal combustion engine according to one of claims 5 to 7, characterized in that one with the camshaft (4) in contact standing Contact element (28) arranged on the carrier body (21) and / or movably mounted, wherein preferably the contact element (28) is designed as a rotatably mounted on the carrier body (21) roller (22). Internal combustion engine according to one of claims 5 to 8, characterized in that the carrier body (21) is rotatably supported by a pivot bearing (19) on the base body (27) and the longitudinal axis (31) of the second piston-cylinder unit (12) with a Auxiliary line 32, which is clamped between a final bearing point of the retracted second piston-cylinder unit (12) and the center of the rotational axis of the pivot bearing (20), an angle β of 45 ° to -45 ° includes or that the support body (21) linear is movably mounted and the longitudinal axis (31) of the second piston-cylinder unit (12) to the longitudinal axis of the linear movement of the carrier body (21) encloses an angle β of 45 ° to -45 ° or is aligned parallel to each other. Internal combustion engine according to one of the preceding claims, characterized in that the first and the second piston-cylinder unit (11, 12) each have a piston (40, 44) biased by a spring (41, 45), a pressure chamber (25, 47 ) and a pressure element (25, 47) at least in phases occlusive blocking element (42, 46). Internal combustion engine according to claim 10, characterized in that the pressure chamber (25) of the first piston-cylinder unit (11) to an outside of the pressure chamber (25) of the intermediate element (8) leading oil passage (33) which in phases by a counter-holder ( 34) is closable. Internal combustion engine according to one of the preceding claims, characterized in that the second piston-cylinder unit (12) in or on the rocker arm (6) and / or the mounting of the carrier body (21) to the Base body (27) is arranged and designed such that for short-term movements (35) of the valves (2, 2 ') by the second piston-cylinder unit (12) influenceable movement (R) of the carrier body (21) relative to the Base body (27) is carried out to a negligible extent or not, preferably this is based in an insignificant extent or not executed movement substantially on the inertia of the rocker arm (6). Internal combustion engine according to claim 12, characterized in that - The camshaft (4) facing first leg (26) of the base body (27) of the rocker arm (6) and - the outlet valve (2, 2 ') facing the second leg (26') of the Grundköpers (27) of the rocker arm (6) each having at least one oil guide channel (18, 18 ', 18 ", 23) are provided with the oil guide channels (18 , 18 ', 18 ", 23) are connected to the oil source and the oil from the oil source arranged in the region of the rocker arm bearing (14) via the oil guide channels (18, 18', 18", 23) to the first and the second piston Cylinder unit (11, 12) can be fed. Internal combustion engine according to one of the preceding claims, characterized in that the hydraulic additional valve control unit (3) is designed such that the intermediate open position (Z) of the exhaust valve (2) is initiated by an exhaust gas flow back-stowed in the exhaust duct (36) and / or the intermediate opened position (Z) of the exhaust valve (2) is initiated by a second control oil circuit acting on the auxiliary hydraulic control unit (3). Method for operating an internal combustion engine with a hydraulic valve clearance compensation (7) and a combined engine accumulator and decompression brake, comprising an internal combustion engine according to one of the preceding claims wherein the rocker arm (6) at least two parts is formed and a carrier body (21) and a base body (27) which in the case of the valve clearance compensation relative movement (R) to each other perform during a short-term movement of the valve (2, 2 '), the second piston-cylinder unit ( 12) due to their arrangement in or on the rocker arm (6) and / or the inertia of the movement of the rocker arm (6) an insignificant or no movement of the carrier body (21) relative to the base body (27) is executed.

Images