DE102019008969B4 - Valve actuation device for an internal combustion engine and method for operating such a valve actuation device - Google Patents

Abstract

Valve actuation device (10) for actuating at least one gas exchange valve (12) of an internal combustion engine (14), with at least one brake rocker arm (34), which can be pivoted about a pivot axis (36) between at least one starting position and at least one actuation position for actuating the gas exchange valve (12). , with at least one actuating element (50) held on the brake rocker arm (34) so as to be movable along a direction of movement (52) relative to the brake rocker arm (34), through which the gas exchange valve ( 12) can be actuated by means of the brake rocker arm (34), and with a chamber (54) partially delimited by the actuating element (50), which can be supplied with a fluid, characterized by at least one pressure accumulator (62), in which when the brake rocker arm moves (34) from the starting position to the actuating position, the fluid can be conveyed from the chamber (54) by means of the actuating element (50) in a fired operation of the internal combustion engine (14) and an actuation of the gas exchange valve (12) by means of the brake rocker arm (34) causes an engine brake ) is omitted.

Description

The invention relates to a valve actuation device for an internal combustion engine according to the preamble of patent claim 1. The invention further relates to a method for operating such a valve actuation device according to the preamble of patent claim 10.

Such a valve actuation device for actuating at least one gas exchange valve of an internal combustion engine and a method for operating such a valve actuation device are already available, for example EP 2 425 105 B1 as known. The valve actuation device comprises at least one rocker arm and can be pivoted about a pivot axis between at least one starting position and at least one actuation position for actuating the gas exchange valve. The valve actuating device further comprises at least one actuating element which is held on the rocker arm and is movable along a direction of movement relative to the rocker arm, through which or via which the gas exchange valve can be actuated, in particular opened, by means of the rocker arm when the rocker arm moves from the starting position into the actuating position . In addition, the valve actuation device has a chamber partially delimited by the actuation element, which can be supplied with a fluid, in particular a liquid.

In addition, the reveals US 2017 / 0 002 702 A1 a four-stroke internal combustion engine which has at least one cylinder and a piston arranged in the cylinder.

The object of the present invention is to further develop a valve actuation device and a method of the type mentioned in such a way that a particularly advantageous operation of the internal combustion engine can be achieved in a particularly simple manner.

This object is achieved by a valve actuation device with the features of patent claim 1 and by a method with the features of patent claim 10. Advantageous embodiments with useful developments of the invention are specified in the remaining claims.

A first aspect of the invention relates to a valve actuation device for actuating at least one gas exchange valve of an internal combustion engine, in particular for a motor vehicle such as a motor vehicle. This means that the motor vehicle, which is preferably designed as a commercial vehicle, has the internal combustion engine, which is preferably designed as a reciprocating piston engine, in its fully manufactured state and can be driven by means of the internal combustion engine. The gas exchange valve is preferably an outlet valve through which a gas, in particular exhaust gas, can be discharged or flow out of a combustion chamber of the internal combustion engine.

The valve actuation device comprises at least one rocker arm, which can be pivoted about a pivot axis between at least one starting position and at least one actuation position for actuating the gas exchange valve, in particular relative to at least one component of the valve actuation device. The component is, for example, a bearing axis, also simply referred to as an axis or rocker arm axis, on which the rocker arm can be mounted so that it can pivot about the pivot axis relative to the bearing axis. By pivoting or moving the rocker arm from the starting position into the actuating position, the gas exchange valve can be or is actuated by means of the rocker arm. The operability or actuation of the gas exchange valve can be understood in particular to mean that the gas exchange valve can be opened or is opened by actuating the gas exchange valve.

For example, during an engine braking operation or during an engine braking operation of the internal combustion engine, the gas exchange valve can be or is actuated by means of the rocker arm, in particular in such a way that the internal combustion engine works as an engine brake or that an engine brake of the internal combustion engine is activated. The rocker arm assigned to an engine brake is also referred to as a brake rocker arm. In other words, in the engine braking operation or during the engine braking operation, which is also referred to as braking operation, an engine brake of the internal combustion engine is activated, so that the internal combustion engine works as an engine brake in the engine braking operation. The engine brake or the engine braking operation is designed in particular as a decompression brake, as is already well known from the general state of the art. During engine braking operation, the gas exchange valve can be or is actuated by means of the rocker arm, for example, in such a way that a compressed gas is compressed, for example by means of a piston of the internal combustion engine that partially delimits the aforementioned combustion chamber is or was, in particular in the compressed state of the gas, discharged from the combustion chamber via the gas exchange valve, in particular by opening the gas exchange valve, so that compression energy contained in the compressed gas is at least predominantly lost unused and therefore not or only very slightly after the gas has been compressed is used to move the piston from its top dead center to its bottom dead center. The internal combustion engine must or had to provide compression energy to compress the gas before the compressed gas is released. Since this compression work carried out, which is contained in the compressed gas, is not used or only used very little to drive the piston and thus an output shaft of the internal combustion engine, which is designed, for example, as a crankshaft and is in particular articulated to the piston via a connecting rod, the motor vehicle in the engine braking operation and thus braked by means of the internal combustion engine acting as an engine brake, or an excessive increase in the driving speed at which the motor vehicle is traveling can be avoided by the engine braking operation.

The valve actuating device comprises at least one actuating element, for example designed as a piston or pin, which is movably held on the rocker arm and can be moved along a direction of movement relative to the rocker arm, in particular translationally. In other words, the actuating element is held on the rocker arm so that it can move along a direction of movement relative to the rocker arm, so that the actuating element can be pivoted, for example, with the rocker arm between the starting position and the actuating position about the pivot axis. Through the actuation element, when the rocker arm moves from the initial position to the actuation position, the gas exchange valve can be actuated, in particular opened, by means of the rocker arm. In other words, the actuating element is arranged such that, for example, during engine braking operation, that is, while the engine braking operation and thus the engine brake are activated, an actuating force for actuating the gas exchange valve acts from the rocker arm via the actuating element on the gas exchange valve, whereby the gas exchange valve over the actuating element can be actuated or is actuated by means of the rocker arm, in particular in the manner of a decompression brake.

The valve actuating device also has a chamber partially delimited by the actuating element, which can be supplied with a fluid, in particular with a liquid such as an oil. This means that the fluid can or can be introduced into the chamber. The chamber is arranged, for example, in the rocker arm and is delimited partly by the actuating element and partly by the rocker arm, in particular directly.

In order to be able to realize a particularly advantageous operation of the internal combustion engine in a particularly cost-effective manner, it is provided according to the invention that the valve actuation device has at least one pressure accumulator, in which the fluid can be conveyed from the chamber by means of the actuating element when the rocker arm moves from the starting position is. In other words, the actuating element is movable, for example, along the direction of movement relative to the rocker arm between at least one transmission position and at least one conveying position, in particular translationally. For example, a movement of the actuating element from the conveying position into the transfer position leads to an increase in the volume of the chamber. Thus, for example, a movement of the actuating element from the transfer position into the conveying position leads to a reduction in the volume of the chamber. For example, during engine braking operation, that is, when the engine brake is activated, the actuating element is secured against movement from the transmission position into the delivery position, in particular hydraulically and/or by means of the fluid received in the chamber, in particular in such a way that during the movement of the Rocker arm from the starting position into the actuating position prevents fluid from flowing out of the chamber, so that when the rocker arm is pivoted from the starting position into the actuating position while the actuating element is secured against movement from the transfer position into the delivery position, the gas exchange valve opens is actuated in the previously described manner via the actuating element by means of the rocker arm, thus the actuating force is transmitted from the rocker arm to the gas exchange valve via the actuating element.

The engine braking operation coincides, for example, with an unfired operation of the combustion chamber or the internal combustion engine, so that, for example, combustion processes occurring in the combustion chamber, in particular in the internal combustion engine as a whole, during unfired operation do not occur.

If the engine braking operation and thus the engine brake are deactivated, the actuating element is, for example, released for movement from the transmission position into the delivery position ben, in particular by allowing the fluid initially received in the chamber to flow out of the chamber during or during the movement of the rocker arm from the starting position into the actuating position. The engine braking operation is deactivated, for example, during a fired operation of the internal combustion engine, with combustion processes taking place in the combustion chamber, in particular in the internal combustion engine, during the fired operation. During fired operation, the gas exchange valve is not actuated by means of the rocker arm and in the manner of a decompression brake or which causes an engine brake. If, for example, the rocker arm is pivoted from the starting position into the actuating position while the actuating element is released for movement from the transfer position into the conveying position, then, for example, the actuating element is moved out of the transfer position by a reaction or movement force acting at least indirectly from the gas exchange valve on the actuating element moved into the delivery position relative to the rocker arm along the direction of movement, while the gas exchange valve is not actuated or opened. The movement of the actuating element from the transfer position into the delivery position is accompanied by a reduction in the volume of the chamber, whereby the fluid initially received in the chamber, which was introduced into the chamber before the volume was reduced, for example, and is therefore received in the chamber, by means of the actuating element is conveyed out of the chamber and into the pressure accumulator. As a result, the fluid conveyed out of the chamber by means of the actuating element and conveyed into the pressure accumulator is received or stored in the pressure accumulator. In this way, the actuating element can be used, for example, as a pressure pump, in particular as a high-pressure pump, by means of which the fluid can be conveyed at a pressure to and in particular into the pressure accumulator, the fluid being stored at the pressure in the pressure accumulator by means of the pressure accumulator can. In other words, the aforementioned pressure can be brought about or generated by means of the actuating element. This pressure generation can be realized by means of an already existing component in the form of the actuating element and thus in a way that is economical in terms of weight, cost and installation space. By using the pressure accumulator, the fluid having the pressure can be stored in a cost-, space- and weight-efficient manner and, for example, can be used as needed after the fluid has been conveyed into the pressure accumulator. Overall, it can be seen that the actuating element, for example when the actuating element is designed as a piston, is used together with the rocker arm as a piston pump in order to convey the fluid into the pressure accumulator and in the pressure accumulator with a pressure that can be brought about, in particular by means of the actuating element can be generated to store pressure in the pressure accumulator.

In order to be able to convey the fluid particularly advantageously and store it in the pressure accumulator, so that a particularly advantageous operation of the internal combustion engine can be realized, it is provided in one embodiment of the invention that the valve actuating device has a spring element. By means of the spring element, when the rocker arm moves from the actuating position to the starting position, the actuating element can be moved along the direction of movement relative to the rocker arm from the conveying position to the transfer position, in particular translationally. This enables a defined and targeted movement of the actuating element from the conveying position to the transfer position. Since a or the movement of the actuating element from the conveying position into the transfer position is accompanied by an increase in the volume of the chamber, the fluid can be introduced into the chamber, in particular sucked in by means of the actuating element, for example by or during the movement of the actuating element from the conveying position into the transfer position . This can ensure targeted and needs-based delivery of the fluid via the chamber in the pressure accumulator.

The pressure accumulator is preferably, in particular completely, arranged outside the rocker arm and outside the actuating element, whereby, for example, a particularly large amount of fluid can be stored in the pressure accumulator. For example, the internal combustion engine can have several combustion chambers and a rocker arm for each combustion chamber, to which the previous and following statements can be transferred to the rocker arm and vice versa. A plurality of rocker arms and a plurality of chambers can thus be provided, with the fluid from the plurality of chambers, in particular under pressure, being able to be received and stored, for example in the pressure accumulator or in one and the same pressure accumulator. As a result, a supply of at least one device of the internal combustion engine with the fluid, in particular under pressure, from the pressure accumulator can be ensured in a particularly simple and particularly low-weight, cost-effective and space-saving manner. Since the fluid in the pressure accumulator has the aforementioned pressure or is to be stored or stored under pressure, the fluid can be provided by the pressure accumulator as a pressure fluid, in particular as a pressure oil. The pressurized fluid that can be provided by the pressure accumulator can be used, for example, to supply at least one device of the internal combustion engine with the pressurized fluid and thereby operate or actuate it by means of the pressurized fluid.

A further embodiment is characterized in that the movement of the actuating element from the conveying position into the transfer position leads to an increase in the volume of the chamber or causes an increase in the volume of the chamber. In other words, the volume of the chamber can preferably be increased by moving the actuating element from the conveying position into the transfer position.

It has proven to be particularly advantageous if at least a portion of the actuating element arranged in the rocker arm in the conveying position moves out of the rocker arm, in particular along the direction of movement and/or translationally, during or as a result of the movement of the actuating element from the conveying position into the transfer position . As a result, a dual function of the rocker arm and the actuating element can be realized in a particularly advantageous manner, so that the number of parts, the costs, the weight and the installation space requirement can be kept particularly low. As part of the dual function, the rocker arm and the actuating element are used on the one hand during engine braking operation or when engine braking operation is activated in order to implement the engine brake described above or to operate the internal combustion engine as an engine brake, in particular in the manner of a decompression brake. For this purpose - while the engine braking operation is activated - the actuating element is secured against movement from the transmission position into the delivery position, so that when the rocker arm and with it the actuating element are pivoted from the starting position into the actuating position, the gas exchange valve is activated via the actuating element by means of the rocker arm , in particular in the manner of a decompression brake, is actuated, in particular opened. On the other hand, as part of the dual function, the rocker arm and the actuating element are used as a pump, in particular as a piston pump, in particular when the engine braking operation is deactivated, that is to say when the engine braking operation is deactivated and thus in particular during the fired operation of the internal combustion engine, by means of which the fluid from the Chamber is conveyed into the pressure accumulator. The pivoting of the rocker arm from the starting position into the actuating position when the actuating element is released for movement from the transfer position into the conveying position requires a movement of the actuating element from the transfer position into the conveying position, since when the rocker arm is out of the Starting position is pivoted into the actuating position, the actuating element initially in the transfer position is supported at least indirectly, in particular directly, on the gas exchange valve, for example in its closed position, or in at least indirect, in particular direct, support system with the gas exchange valve, for example in its closed position comes. As a result, the previously described motive force occurs, which acts at least indirectly from the gas exchange valve on the actuating element, in particular in such a way that the actuating element is moved from the transmission position into the delivery position by means of the motive force. As a result, the fluid previously introduced into the chamber and thus received in the chamber is conveyed out of the chamber and into the pressure accumulator.

If the rocker arm is then pivoted from the actuating position into the starting position, in particular pivoted back, the actuating element is moved from the conveying position into the starting position, in particular by means of the spring element. This is accompanied, for example, by an increase in the volume of the chamber, so that fluid can be introduced into the chamber, in particular sucked in. The fluid initially taken up in the chamber can then be conveyed out of the chamber again in the manner described and conveyed into the pressure accumulator.

In order to be able to realize a particularly advantageous operation of the internal combustion engine in a particularly cost-effective manner, it is provided in a further embodiment of the invention that the valve actuating device has at least one camshaft, by means of which the gas exchange valve is provided via the rocker arm and/or at least one in addition to the gas exchange valve. second gas exchange valve of the internal combustion engine can be actuated. The camshaft has, for example, a cam which can be rotated with the camshaft about a camshaft rotation axis. For example, the rocker arm can be actuated by means of the cam and thus by means of the camshaft and can thereby be pivoted from the starting position into the actuating position, so that pivoting of the rocker arm from the starting position into the actuating position can be effected by means of the cam or by means of the camshaft. This causes or causes the previously described actuation of the gas exchange valve when the engine brake is deactivated, and when the engine brake is activated, the previously described delivery of the fluid by means of the camshaft is caused or caused.

The valve actuating device also includes at least one phase adjuster, by means of which the camshaft can be phase-adjusted, that is, rotated, relative to the aforementioned output shaft of the internal combustion engine. The camshaft can be driven, for example, by the output shaft and can therefore be rotated about the camshaft rotation axis. By means of the phase adjuster, the camshaft can be rotated relative to the output shaft, in particular while the camshaft is coupled to the output shaft, in particular in a torque-transmitting manner. In this way, for example, by means of the phase adjuster, valve control times, i.e. times at which the respective gas exchange valve is actuated by means of the camshaft, can be set, that is, changed or varied.

The phase adjuster can be supplied with the fluid received or stored in the pressure accumulator by means of the pressure accumulator, whereby the camshaft can be phase-adjusted relative to the output shaft by means of the phase adjuster. In other words, the phaser can be supplied with the pressure fluid stored in the pressure accumulator, whereby the phaser can be actuated or operated by means of the pressure fluid, and whereby the camshaft can be rotated relative to the output shaft by means of the phaser. The invention thus enables a particularly cost-effective supply of the phase adjuster with the pressure fluid, so that the camshaft can be rotated, that is, phase-adjusted, relative to the output shaft in a particularly cost-effective manner.

Since the phase adjuster can be supplied with the pressure fluid from the pressure accumulator and can therefore be operated by means of the pressure fluid from the pressure accumulator, and since the pressure fluid is preferably a liquid, the phase adjuster, also known as a camshaft adjuster or camshaft adjuster, is a hydraulic phase adjuster. The invention is based on the following findings: In modern internal combustion engines, the use of hydraulic camshaft actuators to change the phase position of the camshaft is becoming increasingly difficult, in particular due to optimizations in the engine oil circuit with regard to pressure and volume flow. In order to implement an automatic start-stop system and thus, for example, in start-stop conditions, mechanical locking elements in the camshaft actuator are usually used in order to ensure defined starting conditions, for example when the internal combustion engine is automatically started after an automatic deactivation.

In order to be able to realize this, it is usually provided that an oil circuit system of an internal combustion engine is divided into a low-pressure circuit and a high-pressure circuit. For this purpose, it is usually necessary to use an appropriate pressure control on an oil pump to pump the oil, or a pump with variable delivery capacity is used to pump the oil. It is also conceivable to use an additional electric oil pump. In addition, camshaft actuators with an integrated oil reservoir are conceivable in order to achieve a sufficiently high adjustment speed. With regard to a camshaft actuator, it is particularly desirable to achieve high adjustment speeds with which the camshaft can be phase-adjusted.

The invention now relies on the actuating element that is already provided in order to implement the previously described, in particular hydraulic, pump and subsequently to bring about a sufficiently high pressure of the fluid by means of the pump and to store the fluid with the pressure in the pressure accumulator. In this way, an advantageous supply of the phase adjuster with the pressure fluid can be ensured in a simple manner, and by using the high-pressure fluid to operate or actuate the phase adjuster, sufficiently high adjustment speeds can be achieved, with which the camshaft is phase-adjusted relative to the output shaft by means of the phase adjuster can be. The delivery of the fluid into the pressure accumulator, whereby the fluid is stored in the pressure accumulator and stored with the pressure in the pressure accumulator, is also referred to as loading the pressure accumulator.

The camshaft that can be adjusted by means of the phase adjuster is, for example, an intake camshaft, by means of which at least one intake valve of the internal combustion engine can be actuated. Furthermore, it is conceivable that the camshaft is an exhaust camshaft, by means of which at least one exhaust valve of the internal combustion engine can be actuated. In other words, the gas exchange valve that can be actuated by means of the camshaft can be an inlet valve or an outlet valve. In particular, it is conceivable to supply several phase adjusters with the fluid stored in the pressure accumulator, for example a first of the phase adjusters being assigned to an intake camshaft and a second of the phase adjusters being assigned to an exhaust camshaft is. In this way, particularly advantageous operation of the internal combustion engine can be ensured in a particularly simple manner.

In particular, it is conceivable that the camshaft is rotated, i.e. phase-adjusted, relative to the output shaft by means of the phaser when the engine brake is activated compared to a state in which the engine brake is deactivated. In particular, it is conceivable to simultaneously adjust the intake camshaft and the exhaust camshaft by means of the phase adjusters, in particular when activating or deactivating the engine braking operation, by supplying the phase adjusters with the fluid from the pressure accumulator. Furthermore, it is, for example, alternatively or additionally conceivable to use the fluid from the pressure accumulator to secure the actuating element against movement from the transfer position into the conveying position or to secure the actuating element against movement from the transfer position into the conveying position.

The use of the pressure accumulator makes it possible, in particular, to provide a particularly large amount of the fluid having the pressure in a short time, so that switching tasks can be implemented with a sufficiently high adjustment speed. These switching tasks include, for example, activating or deactivating engine braking operation. The switching tasks therefore include, for example, a phase adjustment of the camshaft relative to the output shaft that is effected or is to be effected by means of the phase adjuster. Alternatively or additionally, the switching tasks include securing the actuating element against movement from the transfer position into the conveying position.

The invention allows pressure control of a pump such as an oil pump to be avoided. The pump is used, for example, to convey the fluid through a fluid circuit and/or to convey the fluid into the chamber, in particular via the fluid circuit. Furthermore, a pump with variable delivery capacity for conveying the fluid can be dispensed with, and the invention also makes it possible to dispense with an additional electric pump. This means that the number of parts, costs, weight and installation space requirements can be kept particularly low.

In comparison to conventional solutions, conventionally provided springs on the rocker arms can also be omitted, in particular by using the pressure accumulator as a hydraulic spring, for example to move the actuating element from the delivery position into the transmission position. In particular, the use of the pressure accumulator enables particularly fast switching times or switch-on and switch-off times, for example to switch between fired operation and engine braking operation. In particular, the invention can be used particularly advantageously for start-stop systems or for start-stop applications.

In order to realize a particularly advantageous operation of the internal combustion engine and, for example, to be able to activate and deactivate the engine braking operation in a particularly defined and needs-based manner and thus, for example, to be able to switch between the engine braking operation and the fired operation as needed, it is provided in a further embodiment of the invention that the valve actuation device has at least one supply line having. The fluid conveyed from the chamber by means of the actuating element can flow through the supply line. The fluid from the chamber conveyed by means of the actuating element and thereby flowing through the supply line can be guided to and in particular into the pressure accumulator by means of the supply line. At least one valve element is arranged in the supply line, which can be adjusted between at least one closed state and at least one release state. In the closed state, the supply line is blocked at least in the direction of the pressure accumulator by means of the valve element, so that no fluid can flow from the chamber via the supply line to and into the pressure accumulator. In the release state, the valve element releases the supply line at least in the direction of the pressure accumulator, so that in the release state the fluid can flow from the chamber via the supply line to and in particular into the pressure accumulator.

The closed state is a first state or is also referred to as a first state, with the release state also being referred to as a second state or is a second state. The closed state corresponds, for example, to at least one closed position of the valve element, the release state corresponding, for example, to at least one release position of the valve element. In this case, for example, the valve element can be moved between the closed position and the release position, in particular translationally and/or relative to the previously mentioned component.

In order to be able to activate and deactivate the engine braking operation in a particularly simple and therefore cost-effective manner and thus to be able to switch, for example, between the engine braking operation and the fired operation, it is provided in a further embodiment of the invention that the valve actuation actuation device has an actuating line, via which the valve element can be supplied, in particular acted upon, by means of the pressure accumulator with fluid received by the internal pressure accumulator, whereby the valve element can be adjusted from at least one of the states to the other state, in particular from the closed state to the release state. By supplying, in particular pressurizing, the valve element with the fluid from the pressure accumulator via the actuation line, the fluid can, for example, at least indirectly, in particular directly, exert a switching force on the valve element. By means of the switching force, the valve element can be adjusted from one state to the other state, in particular from the release state to the firing state. As a result, a particularly simple and therefore cost-effective adjustment of the valve element from one state to the other state can be achieved.

A further embodiment is characterized in that a valve device is arranged in the actuating line, which is adjustable between at least one blocking state that blocks the actuating line at least in the direction of the valve element as a third state and at least one open state that releases the actuating line at least in the direction of the valve element as a fourth state . This allows the engine braking operation to be activated and deactivated particularly as needed.

It has proven to be particularly advantageous if the valve device is designed as an electrically actuated valve device and can therefore be adjusted from the third state to the fourth state and/or from the fourth state to the third state by means of electrical energy, in particular electrical current. As a result, an adjustment of the valve device and subsequently an adjustment of the valve element can be effected in a particularly needs-based manner.

The locked state corresponds, for example, to a locked position, with the open state corresponding, for example, to an open position. For example, the valve element can be moved between the blocking position and the open position, in particular translationally and/or relative to the component. As a result, the installation space requirement can be kept particularly low.

A second aspect of the invention relates to a method for operating a valve actuation device, in particular a valve actuation device according to the invention according to the first aspect of the invention, for actuating at least one gas exchange valve of an internal combustion engine, in particular for a motor vehicle. In the method, the valve actuation device has a rocker arm which can be pivoted about a pivot axis between at least one starting position and at least one actuation position for actuating the gas exchange valve. In the method, the valve actuating device also has an actuating element which is held on the rocker arm and can be moved along a direction of movement, in particular translationally, relative to the rocker arm, through which the gas exchange valve can be actuated by means of the rocker arm when the rocker arm moves from the starting position into the actuating position. In addition, in the method, a chamber partially delimited by the actuating element, in particular directly, is supplied with a fluid, in particular with a liquid such as an oil. For this purpose, for example, the fluid is conveyed by means of a pump, in particular conveyed into the chamber.

In order to be able to realize a particularly advantageous operation of the internal combustion engine in a particularly cost-effective manner, it is provided in the second aspect of the invention that the valve actuation device has a pressure accumulator. When or as a result of a movement of the rocker arm from the starting position into the actuating position, the fluid is conveyed from the chamber into the pressure accumulator by means of the actuating element. Advantages and advantageous refinements of the first aspect of the invention are to be viewed as advantages and advantageous refinements of the second aspect of the invention and vice versa.

Further advantages, features and details of the invention result from the following description of a preferred exemplary embodiment and from the drawing.

Further advantages, features and details of the invention result from the following description of a preferred exemplary embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and/or shown alone in the single figure can be used not only in the combination specified in each case, but also in other combinations or on their own, without the frame of the invention.

The drawing shows in the single figure a schematic representation of a valve actuation device according to the invention for actuating at least one gas exchange valve of an internal combustion engine for a motor vehicle.

The only figure shows a schematic representation of a valve actuation device 10 for actuating at least one gas exchange valve 12 of an internal combustion engine 14, which can be seen in detail in the figure. In its fully manufactured state, the internal combustion engine 14 includes the valve actuation device 10. For example, the internal combustion engine 14 is part of a motor vehicle, which in its fully manufactured state includes the internal combustion engine 2614 and can be driven by means of the internal combustion engine 14. The internal combustion engine 14 has a crankcase 16, which has, forms or delimits at least one cylinder 18. A piston 20 is accommodated in the cylinder 18 in a translationally movable manner, so that the piston 20 is translationally movable relative to the crankcase 16. The piston 20 is articulated via a connecting rod 22 to a crankshaft 24 shown particularly schematically in the figure, the crankshaft 24 being rotatable about a crankshaft rotation axis 26 relative to the crankcase 16. The cylinder 18, the piston 20 and a cylinder head 29, not shown, each partially delimit a combustion chamber 28 of the internal combustion engine 14, the gas exchange valve 12 being assigned to the combustion chamber 28. The gas exchange valve 12 is held movably in the cylinder head 29 in a known manner. In particular, the gas exchange valve 12 is used to control a charge exchange or a charge change of the combustion chamber 28. The charge change is understood to mean an inflow of air into the combustion chamber 28 and an outflow of a gas, such as exhaust gas, from the combustion chamber 28. For example, the gas exchange valve 12 is designed as an outlet valve through which a gas such as exhaust gas or air can flow out of the combustion chamber 28. However, the previous and following statements regarding the gas exchange valve 12 can also be easily transferred to an intake valve and an actuation of the intake valve of the internal combustion engine 14.

The gas exchange valve 12 can be moved along an actuation direction illustrated in the figure by a double arrow 30 relative to the crankcase 16 or to the cylinder head 29 between at least one closed position and at least one open position, in particular translationally. The gas exchange valve 12 is assigned a valve spring 32, which is tensioned and in particular compressed by opening the gas exchange valve 12, that is to say by moving the gas exchange valve 12 from the closed position to the open position, and subsequently provides a spring force. By means of the spring force, the gas exchange valve 12 can be moved from the open position into the closed position and, in particular, can be held in the closed position.

The gas exchange valve 12 is held or mounted on the cylinder head 29 so that it can move along the actuation direction relative to the cylinder head 29, in particular translationally, and is therefore movable along the actuation direction relative to the cylinder head 29 between the open position and the closed position. The cylinder head 29 is formed separately from the crankcase 16 and is connected to the crankcase 16. The cylinder head 29 forms or delimits a gas channel assigned to the gas exchange valve 12 and the combustion chamber 28 and designed, for example, as an outlet channel, into which, for example, the gas can flow out of the combustion chamber 28 via the gas exchange valve 12, in particular when the gas exchange valve 12 is open, that is when the gas exchange valve 12 is in its open position.

The valve actuation device 10 comprises a rocker arm 34 assigned to the gas exchange valve 12, which can be pivoted about a pivot axis 36 relative to a component designed here as an axis 38 between at least one starting position and at least one actuation position. The axis 38 is also referred to as the rocker arm axis and is a component of the valve actuation device 10 or the internal combustion engine 14.

In addition, the valve actuating device 10 includes a camshaft 40, which is rotatable about a camshaft rotation axis 42 relative to the cylinder head 29, relative to the crankcase 16 and, for example, relative to the component (axis 38). The crankshaft axis of rotation 26 is spaced from the camshaft axis of rotation 42, with the camshaft axis of rotation 42 and the crankshaft axis of rotation 26 running parallel to one another. The pivot axis 36 is spaced from the crankshaft rotation axis 26 and from the camshaft rotation axis 42 and runs parallel to the camshaft rotation axis 42 and to the crankshaft rotation axis 26. The camshaft 40 has a cam 44, by means of which the rocker arm 34 can be actuated, in particular via a transmission element 46, and therefore in particular can be pivoted from the starting position into the operating position.

In the exemplary embodiment shown in the FIG Actuating the gas exchange valve 12. If the rocker arm 34 is assigned to an engine brake as in the exemplary embodiment shown in the figure, the rocker arm 34 is also referred to as a brake rocker arm or engine brake rocker arm. In the engine braking operation or during the engine braking operation, the internal combustion engine 14 works as an engine brake, in particular in the manner of a decompression brake, by means of which the motor vehicle can be braked, for example. This can be understood in particular to mean that a speed at which the motor vehicle is traveling is reduced and/or that an excessive increase in the speed, also referred to as the driving speed, is avoided by means of the engine brake. During engine braking operation, the gas exchange valve 12 is operated by means of the rocker arm 34, in particular in the manner of a decompression brake, which is already well known from the general state of the art. Expressed again in other words, it is preferably provided that the engine brake, which is activated during engine braking operation, is designed as a decompression brake. The cam 44 is therefore preferably a so-called brake cam.

The transmission element 46 is, for example, a roller which can be rotatably held on the rocker arm 34. In a base circle phase 48 of the camshaft 40 that is different from the cam 44, the rocker arm 34 is not actuated or pivoted by the camshaft 40 from the starting position into the actuating position, so that the rocker arm 34 can be actuated by means of the cam 44 and can therefore be pivoted from the starting position into the actuating position is. Overall, it can be seen that the gas exchange valve 12 can be actuated, in particular opened, via the rocker arm 34 by or by means of the camshaft 40.

The valve actuating device 10 further comprises an actuating element, in the present case designed as a piston 50, which is held on the rocker arm 34 in a translationally movable manner relative to the rocker arm 34 along a direction of movement. The direction of movement is illustrated in the figure by a double arrow 52. The piston 50 can be moved along the direction of movement relative to the rocker arm 34 in translation between at least one delivery position shown in the figure and at least one transmission position. In the delivery position, at least a portion T of the piston 50 is arranged in the rocker arm 34 or within the rocker arm 34. In the transmission position, however, at least the partial area T is arranged outside the rocker arm 34. In other words, if the piston 50 is moved translationally from the delivery position into the transmission position along the direction of movement relative to the rocker arm 34, the partial region T arranged in the rocker arm 34 in the delivery position is thereby moved out of the rocker arm 34 along the direction of movement. If the piston 50 is moved translationally from the transfer position into the conveying position along the direction of movement relative to the rocker arm 34, the partial area T arranged in the transfer position outside the rocker arm 34 is moved into the rocker arm 34 along the direction of movement.

The valve actuating device 10 also has a chamber 54, shown particularly schematically in the figure, which in the present case is arranged at least partially, in particular at least predominantly or completely, in the rocker arm 34 and is partially delimited by the rocker arm 34 and by the piston 50. The chamber can be supplied with a fluid. In other words, the fluid can be introduced into the chamber. The fluid is preferably a liquid. In particular, the fluid or liquid is an oil, also referred to as engine oil, which flows through, for example, a circuit also referred to as an oil circuit or fluid circuit. In other words, the valve actuation device 10 or the internal combustion engine 14 can comprise a circuit, also referred to as a fluid circuit or oil circuit, through which the fluid can flow. For example, a pump (not shown in the figure) is arranged in the circuit, by means of which the fluid can be conveyed or is conveyed through the circuit. If the fluid is in the form of oil, the pump is also referred to as an oil pump.

In the figure, a channel 56, also referred to as an oil channel or designed as an oil channel, can be seen particularly schematically, through which the fluid, in particular the oil, can flow. For example, the channel 56 is a so-called main oil gallery, which runs or is accommodated at least partially, in particular at least predominantly or completely, in the crankcase 16 or within the crankcase 16. In particular, the channel 56 is completely circumferentially bounded along its circumferential direction by the crankcase 16, in particular directly, so that the oil flowing through the channel 56 can directly touch the crankcase 16 or a wall of the crankcase 16 that directly delimits the channel 56 in its circumferential direction.

The valve actuation device 10 also includes a supply channel designated supply line 58, which can be supplied via the channel 56 with the oil flowing through the channel 56. Thus, at least part of the oil flowing through the channel 56 can flow out of the channel 56 and flow into the supply line 58 and then flow through the supply line 58. By means of the supply line 58, the oil flowing through the supply line 58 can be introduced to and in particular into the chamber 54, so that the chamber 54 can be supplied with the oil, in particular from the channel 56, via the supply line 58. In the exemplary embodiment shown in the figure, the supply line 58 branches off from the channel 56, wherein the supply line 58 can, for example, run at least partially, in particular at least predominantly or completely, outside the crankcase 16. Furthermore, it is conceivable that the supply line 58 runs at least partially, in particular at least predominantly, in the crankcase 16.

It can be seen from the figure that a check valve 60 is arranged in the supply line 58, which opens in the direction of the chamber 54 and blocks in the opposite direction. As a result, the oil flowing through the supply line 58 can flow out of the supply line 58 via the check valve 60 and flow into the chamber 54, whereby the chamber 54 can be supplied or is supplied with the oil. However, the check valve 60 prevents the oil from flowing from the chamber 54 back into the supply line 58 via the check valve 60. For example, an initial pressure of the oil can be achieved using the oil pump. In other words, the oil can be conveyed at a first pressure through the channel 56 and through the supply line 58 by means of the oil pump. This first pressure is labeled p _LP and is also referred to as low pressure. This means that the chamber 54 can be supplied or is supplied with the low-pressure oil via the supply line 58, in particular by means of the pump.

In order to be able to realize a particularly advantageous operation of the internal combustion engine 14 in a particularly cost-effective manner, the valve actuation device 10 has a pressure accumulator 62. The pressure accumulator 62 is also referred to as a pressure accumulator or is a pressure accumulator. Alternatively or additionally, the pressure accumulator 62 is at least partially, in particular at least predominantly or completely, arranged outside the rocker arm 34, outside the chamber 54 and outside the piston 50 as well as outside the gas exchange valve 12. In particular, the pressure accumulator 62 is at least partially, in particular at least predominantly or completely, arranged outside the crankcase 16 and outside the combustion chamber 28. As will be explained in more detail below, when or as a result of a movement of the rocker arm 34 from the starting position to the actuating position, the oil can be conveyed from the chamber 54 into the pressure accumulator 62 by means of the piston 50 and can subsequently be received or stored in the pressure accumulator 62. By means of the piston 50, in particular by conveying the oil from the chamber 54 into the pressure accumulator 62, a second pressure of the oil which is greater than the first pressure p _LP can be caused or generated, the second pressure also being referred to as high pressure. The high pressure is designated p _HP in the figure. The oil can be stored at high pressure in the pressure accumulator 62. In other words, the oil stored in the pressure accumulator 62 is at high pressure.

It can be seen from the figure that a movement of the piston 50 from the delivery position into the transfer position leads to an increase in the volume of the chamber 54 or is accompanied by an increase in the volume of the chamber 54 or causes an increase in the volume of the chamber 54. As a result, a movement of the piston 50 from the transfer position into the delivery position leads to a reduction in the volume of the chamber 54, so that by moving the piston 50 from the transfer position into the delivery position, the oil, which was previously introduced into the chamber 54 via the supply line 58, is released by means of the Piston 50 is conveyed out of the chamber 54 and into the pressure accumulator 62. This movement of the piston 50 from the transmission position into the delivery position is caused by pivoting the rocker arm 34 from the starting position into the actuation position. In other words, if the rocker arm 34 and with it the piston 50 held on the rocker arm 34 are pivoted from the starting position into the actuation position by means of the cam 44, while the piston 50 is released for movement from the transmission position into the delivery position, this is what happens Pistons initially in the transfer position in at least indirect, in particular direct, support contact with the gas exchange valve 12. The gas exchange valve 12 is in its closed position or is held in the closed position by means of the valve spring 32. Due to the support system described above, the gas exchange valve 12, by being held in the closed position by means of the valve spring 32, at least indirectly exerts a reaction or movement force on the piston 50, which is initially in the transfer position. By means of the motive force, the piston 50 is released from the transfer position into the delivery position because it is released for movement from the transfer position into the delivery position The position moves translationally along the direction of movement relative to the rocker arm 34. As a result, the oil initially located in the chamber 54 is conveyed out of the chamber 54 by means of the piston 50 and conveyed into the pressure accumulator 62.

In particular, the piston 50 is released for movement from the transmission position into the delivery position during the fired operation of the internal combustion engine 14. To activate the engine braking operation or during the engine braking operation, however, the piston 50 is secured against movement from the transmission position into the delivery position, in particular hydraulically. Then the aforementioned support system does not cause the piston 50 to be moved from the transmission position into the delivery position, but rather the support system causes the gas exchange valve 12 to move against the valve spring 32 or against the through the piston 50 by means of the rocker arm 34 Valve spring 32 provided spring force is actuated and in this case is opened.

It is also conceivable that the rocker arm 34, as a so-called inlet rocker arm, actuates a gas exchange valve 12 designed as an inlet valve.

The valve actuation device 10 includes at least one phase adjuster 64, which is also referred to as a camshaft adjuster or camshaft adjuster. By means of the phaser 64, the camshaft 40 can be phase-adjusted relative to the crankshaft 24, that is, rotated. The valve actuating device 10 includes an actuating line 66, also known as an adjusting channel, via which the phase adjuster 64 can be supplied with the oil from the pressure accumulator 62, that is to say with the oil received in the pressure accumulator 62, whereby the camshaft 40 is adjusted relative to the camshaft by means of the phase adjuster 64 Crankshaft 24 is phase-adjustable, that is, rotatable. For this purpose, the phase adjuster 64 has, for example, chambers A and B, which follow one another in the circumferential direction of the phase adjuster 64. A supply of the phase adjuster 64 with the oil from the pressure accumulator 62 can be adjusted as required via a valve unit 68 arranged in the control line 66, whereby, for example, by means of the phase adjuster 64, the camshaft 40 can be rotated relative to the crankshaft 24 in a first direction of rotation and in a The second direction of rotation opposite to the first direction of rotation can be effected.

A check valve 70 is arranged in the control line 66, via which the valve unit 68 and thus the phase adjuster 64 can be supplied with the oil from the pressure accumulator 62. The check valve 70 opens in the direction of the valve unit 68 or in the direction of the phase adjuster 64 and blocks in the opposite direction, i.e. in the direction of the pressure accumulator 62. Oil can therefore flow from the control line 66 via the check valve 70 to the valve unit 68 and through the valve unit 68 in flow through the phase adjuster 64, but no oil can flow from the phase adjuster 64 via the valve unit 68 and the check valve 70 into the control line 66.

The valve actuation device 10 also includes a return line 72, via which oil can flow from the phase adjuster 64, for example, into a reservoir 74. For example, the oil from the reservoir 74 can be pumped back into the channel 56 and thus into the supply line 58 using the oil pump. Since the oil can be stored in the pressure accumulator 62 with the second pressure p _HP which is greater than the first pressure p _LP and is also referred to as high pressure, the oil stored or recorded in the pressure accumulator 62 and which can be made available by means of the pressure accumulator 62 is also referred to as pressure oil. Overall, it can be seen that by means of the valve actuating device 10, the second pressure p _HP and thus the pressure oil can be generated particularly easily and thus in a weight-, space- and cost-effective manner. In addition, the phase adjuster 64 can be supplied with the pressure oil from the pressure accumulator 62 in a particularly cost-effective manner and in a particularly tailored manner by means of the valve actuating device 10. Since the pressure oil has the high, second pressure p _HP , sufficiently high adjustment speeds can be achieved with which the camshaft 40 can be rotated relative to the crankshaft 24 by means of the phaser 64, that is, can be adjusted in phase.

The valve actuating device 10 also comprises at least one feed line 76 through which the oil conveyed by means of the piston 50 flows from the chamber 54, by means of which or via which the oil conveyed by means of the piston 50 and thereby flowing through the feed line 76 flows to and in particular into the pressure accumulator 62 is conducted or is to be conducted. A valve element, also referred to as a control valve 78, is arranged in the feed line 76, which is between at least one closing state that blocks the feed line 76 at least in the direction of the pressure accumulator 62 as the first state and at least one that releases the feed line 76 at least in the direction of the pressure accumulator 62 and is shown in FIG .The release state shown can be adjusted as a second state. The closed state corresponds, for example, to a closed position of the control valve 78, the release state corresponding to a release position of the control valve 78.

A spring 80 is assigned to the control valve 78, which is tensioned more strongly in the closed state or in the closed position than in the released state or in the released position and therefore provides a spring force at least in the closed state or in the closed position, by means of which the control valve 78 comes out of the closed state or is adjustable, in particular movable, from the closed position into the release state or into the release position. In particular, the control valve 78 can be held in the release state or in the release position by means of the spring 80 or by means of the spring force provided by the spring 80, the release state or the release position being shown in the figure. The spring 80 is, for example, supported on the one hand at least indirectly, in particular directly, on the control valve 78 and on the other hand at least indirectly, in particular directly, on the rocker arm 34. It is conceivable that the control valve 78 and/or the spring 80 are arranged in the rocker arm 34. At least part of the supply line 76 runs through or in or within the axis 38. Alternatively or additionally, at least part of the supply line 58 runs through and thus in or within the axis 38. Furthermore, at least another part of the supply line 76 runs outside the Axis 38 and within the rocker arm 34. Alternatively or additionally, at least another part of the supply line 58 runs outside the axis 38 and within the rocker arm 34.

In addition, a check valve 82 is arranged in the supply line 76, which is arranged downstream of the control valve 78 and in particular downstream of the axis 38 in the flow direction of the oil flowing out of the chamber through the supply line 76 and thereby to and into the pressure accumulator 62. The check valve 82 is preferably arranged, in particular completely, outside the rocker arm 34 and/or outside the axis 38. The check valve 82 opens in the direction of the pressure accumulator 62 and closes in the opposite direction and thus in the direction of the chamber 54, so that no oil can flow into the chamber 54 via the check valve 82.

Furthermore, it can be seen in the figure that a high-pressure oil gallery 84 runs within the axis 38, through which the high-pressure oil from the chamber 54 can flow. In addition, the axis 38 has a low-pressure oil gallery 86, through which the low-pressure oil from the channel 56 or from the supply line 58 can flow. In particular, it is conceivable that at least part of the high-pressure oil gallery 84 is part of the supply line 76. Alternatively or additionally, at least part of the low-pressure oil gallery 86 is at least part of the supply line 58. In this case, for example, the check valve 82 is arranged downstream of the high-pressure oil gallery 84. Thus, for example, no oil can flow from the pressure accumulator 62 via the check valve 82 into the high-pressure oil gallery 84. The high-pressure oil gallery 84 and the low-pressure oil gallery 86 run within the axis 38 and preferably outside the rocker arm 34.

The valve actuating device 10 also includes a spring element 88, which can be supported or is supported along the direction of movement, on the one hand at least indirectly, in particular directly, on the piston 50 and on the other hand at least indirectly, in particular directly, on the rocker arm 34. The spring element 88 is more tightly tensioned in the conveying position than in the transfer position, so that at least in the conveying position the spring element 88 provides a spring force acting on the piston at least indirectly, in particular directly, along the direction of movement. By means of the spring force provided by the spring element 88, the piston 50 can be moved from the delivery position into the transfer position and preferably held in the transfer position. If the piston 50 is released for movement from the transmission position into the delivery position, in particular while the engine braking operation is deactivated, and the rocker arm 34 is pivoted from the starting position into the actuation position, the piston 50 is moved against the spring element 88 or against the Spring force provided by the spring element 88 is moved from the transfer position into the conveying position as a result of the support system described above or by means of the motive force. As a result, the spring element 88 is tensioned and, in this case, compressed. Preferably, the spring element 88 is at least partially, in particular at least predominantly or completely, arranged in the rocker arm 34. In particular, the piston 50 is moved from the transmission position into the delivery position by means of the cam 44 or while the cam 44 interacts with the transmission element 46. For example, the spring force provided by the spring element 88 holds the rocker arm 34 via the transmission element 46 in cooperation with the camshaft 40, so that, for example, during the base circle phase 48, the piston 50 moves out of the delivery position by means of the spring element 88 or by means of the spring force provided by the spring element 88 the transmission position is moved translationally along the direction of movement relative to the rocker arm 34.

Overall, it can be seen that the rocker arm 34 and the piston 50 are used as a piston pump be det in order to convey the oil from the channel 56 via the chamber 54, in particular periodically, into the pressure accumulator 62 and subsequently store it with the high pressure in the pressure accumulator 62.

The valve actuation device 10 has an actuation line 90, via which the control valve 78 can be supplied, in particular acted upon, by means of the pressure accumulator 62 with the oil held in the pressure accumulator 62. By supplying, in particular applying, the control valve 78 with the oil from the pressure accumulator 62 via the actuating line 90, the control valve 78 can be moved from the release state or from the release position into the closed state, in particular against the spring 80 or against the spring 80 or against the spring 80 Spring 80 provided spring force. This means that the control valve 78 is tensioned, in particular compressed, by adjusting the control valve 78 from the release state to the closed state. By applying the oil from the pressure accumulator 62 to the control valve 78 via the actuation line 90, the oil, in particular in the actuation line 90, exerts a force acting at least indirectly, in particular directly, on the control valve 78, which is due to the high pressure of the oil from the Pressure accumulator 62 is greater than the spring force of the spring 80. As a result, the control valve 78 is adjusted, in particular moved, from the release state to the closed state against the spring force provided by the spring 80.

In order to be able to adjust the control valve 78 as required, a valve device 92 is arranged in the actuating line 90, which is adjustable between at least one blocking state that blocks the actuating line 90 at least in the direction of the control valve 78 and at least one open state that releases the actuating line 90 at least in the direction of the control valve 78 . The blocking state of the valve device 92 is shown in the figure. The blocking state corresponds to a blocking position of the valve device 92, the open state corresponding to an open position of the valve device 92. This means that the valve device 92 assumes the blocked position in the locked state, with the valve device 92 assuming the open position in the open state. The valve device 92 is thus adjustable, in particular movable, in particular translationally and/or relative to the component, between the blocking position and the open position of the valve device 92.

It can be seen from the figure that the valve device 92 has a check valve 94, which in the blocked state is arranged in the actuating line 90 and blocks in the direction of the control valve 78 and opens in the opposite direction and thereby in the direction of the pressure accumulator 62. Thus, for example, in the blocked state, oil coming from the control valve 78 can flow via the check valve 94 in the direction of the pressure accumulator 62 or into the pressure accumulator 62, but in the blocked state no oil can flow from the pressure accumulator 62 via the valve device 92 to the control valve 78. At least a first part of the actuation line 90 runs, for example, outside the rocker arm 34 and/or outside the axis 38. At least a second part of the actuation line 90 runs, for example, inside the rocker arm 34 and outside the axis 38. Furthermore, it is conceivable that at least a third part the actuating line 90 runs within the axis 38 and in particular outside the rocker arm 34. The third part of the actuation line 90 includes, for example, an activation oil gallery p _JB , via which the oil coming from the pressure accumulator 62 and flowing through the actuation line 90 is guided to the control valve 78, thereby supplying the control valve 78 via the actuation line 90 with the pressure oil from the pressure accumulator 62 to act on and subsequently move, for example, from the release state to the closed state. This activates the engine braking operation, so that the activation oil gallery p _JB is used to activate the engine brake.

In the exemplary embodiment shown in the figure, the valve device 92 is designed as an electrically actuated valve device. In particular, the electrically actuable valve device can be a solenoid valve. As a result, the valve device 92 can be adjusted, in particular moved, with electrical energy, in particular by means of electrical current, for example from the blocked state or from the blocked position into the open state or into the open position. The valve device 92 is assigned a further spring 96, which is tensioned, in particular compressed, more strongly in the open state or in the open position of the valve device 92 than in the locked state or in the locked position. As a result, at least in the open state or in the open position of the valve device 92, the spring 96 provides a spring force, by means of which the valve device 92 can be moved from the open state or from the open position into the locked state, in particular into the locked position, and in particular in the locked state or in the locked position is to be kept. Overall, it can be seen that the valve device 92 moves from the locked state to the open state by means of electrical energy against the spring 96 or against the spring force provided by the spring 96 stand is adjustable, in particular movable. Preferably, the valve device 92 and/or the spring 96 is arranged completely outside the rocker arm 34. Furthermore, it is conceivable that the spring 80 is arranged within the rocker arm 34. In comparison to conventional solutions, the piston 50 is not held in the delivery position and thus in a retracted position by means of the spring element 88 during the base circle phase 48, but in the transmission position and thus in an extended position. This allows the rocker arm 34 and the piston 50 to be used as a piston pump to pump the oil from the chamber 54 into the pressure accumulator 62.

In other words, as a result of this and by pivoting the rocker arm 34 from the starting position into the actuating position, the oil is conveyed out of the chamber 54, in particular while the piston 50, also known as a brake piston, is at least indirectly, in particular directly, on the gas exchange valve 12, in particular on it Valve end supported. In a closing phase, that is, when the rocker arm 34, which was previously moved from the starting position into the actuating position by means of the cam 44, moves back from the actuating position into the starting position, the rocker arm 34, also simply referred to as a lever, is moved by the spring element 88 provided spring force, which acts at least indirectly on the brake piston, is held in at least indirect support system and thus in cooperation with the camshaft 40, in particular until the base circle phase 48 is reached.

The oil conveyed from the chamber 54 reaches the high-pressure oil gallery 84 of the axis 38, for example via at least one or more bearings for pivotally supporting the rocker arm 34, in particular on the axis 38, so that the oil is collected, for example, in the high-pressure oil gallery 84. In particular, for example, the oil from all chambers of all rocker arms is collected in the high-pressure oil gallery 84, from where the oil is directed into the pressure accumulator 62. The pressure accumulator 62 is designed for the second pressure p _HP , which is higher than the first pressure p _LP . Upstream of the pressure accumulator 62 and in particular downstream of the high-pressure oil gallery 84 is the check valve 82, designed as a pressure check valve, which prevents the oil from flowing back out of the pressure accumulator 62. The oil and thus a volume flow of the oil that reaches the pressure accumulator 62, in particular via the supply line 76, is, for example, the sum of all partial flows from all brake pistons of all rocker arms. Furthermore, it can be seen that the check valve 60 functions as a suction check valve, which in the aforementioned closing phase accordingly lets oil from the supply line 58 or from the channel 56 into the chamber 54, the check valve 60 during a so-called opening phase, during which the rocker arm 34 moves from the starting position into the actuating position, the supply line 58 for the oil from the chamber 54 closes.

The oil entering the chamber 54 is provided via a low pressure oil supply which includes the main oil gallery and the low pressure oil gallery 86. The pressure check valve is preferably not located directly in the rocker arm 34, but preferably outside the rocker arm 34 and outside the axis 38 and preferably in front of the pressure accumulator 62, in particular in front of an inlet of the pressure accumulator 62, via the inlet of which the oil from the supply line 76 in can flow into the pressure accumulator 62. As a result, an oil volume exchange can take place between the individual chambers or the individual rocker arms, since these are each in different stroke phases or movement phases depending on the ignition sequence of the internal combustion engine 14. This means that the total volume flow of oil delivered can be kept low. At the same time, the effort required for individual check valves on the rocker arms is kept low or avoided.

As soon as a certain pressure level is or is reached in the pressure accumulator 62, an unlocking piston can be activated on the pressure check valve (check valve 82), which opens the check valve 82, in particular both in the direction of the pressure accumulator 62 and in the direction of the chamber 54. As a result The oil can flow from the pressure accumulator 62 back via the supply line 76 to and in particular into the chamber 54, in particular via the control valve 78 which is in the release state. As a result, the pressure accumulator 62 can act as a hydraulic spring, which, for example, supports the spring element 88 in the movement of the piston 50 from the delivery position into the transmission position. In other words, the spring element 88 designed as a mechanical spring can be supported by the hydraulic spring, in particular with regard to causing a movement of the piston from the delivery position into the transmission position, so that the spring element 88 can be dimensioned to be particularly small and thus space-saving and weight-efficient. In addition, a pressure relief valve for a high-pressure oil circuit, which might otherwise be required, can be omitted because if the pressure check valve is opened, the total delivery rate becomes zero. This means that the hydraulic-mechanical efficiency of the entire system can also be improved.

When the engine brake is activated or switched on, for example, the control valve 78, which is located in the rocker arm 34 on a pressure side of the chamber 54, is closed, that is, adjusted to the closed state. As a result, the oil initially taken up in the chamber 54 can no longer flow out of the chamber 54, in particular via the supply line 76. This secures the piston 50 against movement from the transfer position into the delivery position. In other words, a retraction movement of the piston 50, which can move in the course of its retraction movement from the transfer position into the delivery position along the direction of movement relative to the rocker arm 34, for example, is blocked or avoided. As a result, the gas exchange valve 12 can be actuated via the piston 50 and the rocker arm 34 by means of the cam 44, in particular in the manner of a decompression brake. This means that the previously described pumping function of the piston 50 is deactivated when the control valve 78 is in the closed state, so that no more oil is delivered from the chamber 54 into the pressure accumulator 62.

When the engine brake is activated or switched on, the pressure accumulator 62 is discharged. This means that at least part of the oil received in the pressure accumulator 62 is discharged from the pressure accumulator 62 and, in particular via the actuating line 66, to the phase adjuster 64 and, in particular via the actuating line 90, to the control valve 78, in order to thereby on the one hand the engine braking operation to rotate the camshaft 40 relative to the crankshaft 24 and on the other hand to adjust the control valve 78 from the release state to the closed state. By discharging the pressure accumulator 62, for example, no more pressure oil is available. However, a supply of the valve device 92, which is designed, for example, as an electrical control valve, or a supply of the control valve 78, in particular via the valve device 92, with the low-pressure oil, in particular from the channel 56, can be ensured via a shuttle valve 98 of the valve actuating device 10, and via that Shuttle valve 98 can ensure that the phase adjuster 64 is supplied with the low-pressure oil, in particular from the channel 56, in particular until the engine braking operation has ended.

When the engine brake is deactivated or switched off, the control valve 78 is opened, whereby the oil can be pumped from the chamber 54 into the pressure accumulator 62 again by means of the piston 50. The fact that the piston 50, also known as the brake piston, extends with spring support, that is to say it is moved from the delivery position into the transmission position by means of the spring force provided by the spring element 88, whereby at least the partial area T is moved out of the rocker arm 34, and in that the chamber 54 is always filled with oil, a switching time for activating the engine brake or engine braking operation can be reduced compared to conventional systems. When deactivating the engine brake, a switching time required to deactivate the engine brake is positively influenced by the particularly high pressure level of the oil from the pressure accumulator 62 and a correspondingly stronger return spring, the return spring being able to be, for example, the spring 96 and/or the spring 80.

Reference symbol list

10

Valve actuation device

12

Gas exchange valve

14

Internal combustion engine

16

crankcase

18

cylinder

20

Pistons

22

connecting rod

24

crankshaft

26

Crankshaft rotation axis

28

combustion chamber

29

cylinder head

30

Double arrow

32

Valve spring

34

rocker arm

36

Pivot axis

38

axis

40

camshaft

42

Camshaft rotation axis

44

cam

46

Transmission element

48

Base circle phase

50

Pistons

52

Double arrow

54

chamber

56

channel

58

supply line

60

check valve

62

Pressure accumulator

64

Phaser

68

Valve unit

70

check valve

72

return line

74

reservoir

76

Feed line

78

control valve

80

Feather

82

check valve

84

High pressure oil gallery

86

Low pressure oil gallery

88

Spring element

90

Actuation line

92

Valve device

94

check valve

96

Feather

98

Shuttle valve

A

chamber

b

chamber

T

Sub-area

pHP

High pressure

pLP

Low pressure

PJB

Activation Oil Gallery

Claims (10)

Valve actuation device (10) for actuating at least one gas exchange valve (12) of an internal combustion engine (14), with at least one brake rocker arm (34), which can be pivoted about a pivot axis (36) between at least one starting position and at least one actuation position for actuating the gas exchange valve (12). , with at least one actuating element (50) held on the brake rocker arm (34) so as to be movable along a direction of movement (52) relative to the brake rocker arm (34), through which the gas exchange valve ( 12) can be actuated by means of the brake rocker arm (34), and with a chamber (54) partially delimited by the actuating element (50), which can be supplied with a fluid, characterized by at least one pressure accumulator (62), in which when the brake rocker arm moves (34) from the starting position to the actuating position, the fluid can be conveyed from the chamber (54) by means of the actuating element (50) in a fired operation of the internal combustion engine (14) and an actuation of the gas exchange valve (12) by means of the brake rocker arm (34) causes an engine brake ) is omitted. Valve actuation device (10). Claim 1 , characterized by a spring element (88), by means of which, when the brake rocker arm (34) moves from the actuating position to the starting position, the actuating element (50) can be moved along the direction of movement (52) relative to the brake rocker arm (34) from a conveying position to a transfer position is. Valve actuation device (10). Claim 2 , characterized in that the movement of the actuating element (50) from the conveying position into the transfer position causes an increase in the volume of the chamber (54). Valve actuation device (10). Claim 2 or 3 , characterized in that at least one portion (T) of the actuating element (50) arranged in the conveying position in the brake rocker arm (34) moves out of the brake rocker arm (34) when the actuating element (50) moves from the conveying position into the transfer position. Valve actuation device (10) according to one of the preceding claims, characterized by : - at least one camshaft (40), by means of which the gas exchange valve (12) via the brake rocker arm (34) and / or at least one provided in addition to US 2017/0 002 702 A1 , second gas exchange valve of the internal combustion engine (14) can be actuated; and - at least one phase adjuster (64), by means of which the camshaft (40) can be phase-adjusted relative to a crankshaft (24) of the internal combustion engine (14), the phase adjuster (64) being connected to that in the pressure accumulator (62) by means of the pressure accumulator (62). ) absorbed fluid can be supplied, whereby the camshaft (40) can be phase-adjusted relative to the crankshaft (24) by means of the phase adjuster (64). Valve actuating device (10) according to one of the preceding claims, characterized by : - at least one feed line (76) through which the fluid conveyed by means of the actuating element (50) can flow, by means of which the fluid conveyed by means of the actuating element (50) and thereby flowing through the feed line (76). Fluid is to be guided from the chamber (54) into the pressure accumulator (62); and - at least one arranged in the feed line (76). net valve element (78), which can be adjusted between at least one closing state that blocks the feed line (76) at least in the direction of the pressure accumulator (62) as a first state and at least one release state that releases the feed line (76) at least in the direction of the pressure accumulator (62) as a second state is. Valve actuation device (10). Claim 6 , characterized by an actuating line (90), via which the valve element (78) can be supplied with the fluid contained in the pressure accumulator (62) by means of the pressure accumulator (62), whereby the valve element (78) from at least one of the states to the other state is adjustable. Valve actuation device (10). Claim 7 , characterized in that a valve device (92) is arranged in the actuating line (90), which is between at least one blocking state that blocks the actuating line (90) at least in the direction of the valve element (78) as a third state and at least one the actuating line (90). in the direction of the valve element (78) releasing open state can be adjusted as a fourth state. Valve actuation device (10). Claim 8 , characterized in that the valve device (92) is designed as an electrically actuated valve device and can thereby be adjusted from the third state to the fourth state and/or from the fourth state to the third state by means of electrical energy. Method for operating a valve actuation device (10) for actuating at least one gas exchange valve (12) of an internal combustion engine (14), in which the valve actuation device (10) has: - a brake rocker arm (34), which about a pivot axis (36) between at least one starting position and at least one actuation position for actuating the gas exchange valve (12) can be pivoted; - an actuating element (50) which is movably held on the brake rocker arm (34) along a direction of movement (52) relative to the brake rocker arm (34), through which the gas exchange valve (12) is activated when the brake rocker lever (34) moves from the starting position into the actuating position. can be actuated by means of the brake rocker arm (34); and - a chamber (54) partially delimited by the actuating element (50), which is supplied with a fluid, characterized by a pressure accumulator (62), into which the fluid is released when the brake rocker arm (34) moves from the starting position to the actuating position the chamber (54) is conveyed by means of the actuating element (50) in a fired operation of the internal combustion engine (14) and the gas exchange valve (12) is not actuated by means of the brake rocker arm (34), which causes an engine brake.

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