DE202014010758U1 - Switching device with a hydraulic valve for switching an actuating piston - Google Patents

Abstract

Switching device (100) with a hydraulic valve (10) for controlling a hydraulic fluid, in particular for switching an actuating piston (48) in a connecting rod (40) for a variable compression of an internal combustion engine, and with at least one electric coil (30, 32), wherein the Hydraulic valve (10) comprises a valve housing (16) having a first control bore (17) for a first channel (18) and a second control bore (19) for a second channel (20) and having a vent hole (21) for connection with a venting channel (22), wherein in the valve housing (16) a movable piston (12) is arranged which optionally at least in a first switching position (S1) or at least in a second switching position (S2) for acting on the first or second channel ( 18, 20) is displaceable with hydraulic fluid, wherein the at least one coil (30, 32) outside of the valve housing (16) and the piston (12) is arranged and the piston (12) at least ze It is brought into operative connection with the at least one coil (30, 32) in order to move the piston (12) from one switching position (S1, S2) into the respective other switching position (S2, S1).

Description

Technical area

The invention relates to a switching device with a hydraulic valve for controlling a hydraulic fluid, in particular for switching an actuating piston in a connecting rod for a variable compression of an internal combustion engine of a motor vehicle.

State of the art

In internal combustion engines, a high compression ratio has a positive effect on the efficiency of the internal combustion engine. Under compression ratio is generally understood the ratio of the entire cylinder space before compression to the remaining cylinder space after compression. In internal combustion engines with spark ignition, in particular gasoline engines, which have a fixed compression ratio, however, the compression ratio may only be selected so high that a so-called "knocking" of the internal combustion engine is avoided at full load operation. However, for the much more frequently occurring partial load range of the internal combustion engine, that is to say with low cylinder filling, the compression ratio could be selected with higher values without "knocking" occurring. The important part load range of an internal combustion engine can be improved if the compression ratio is variably adjustable. For the adjustment of the compression ratio, for example, systems with variable connecting rod length are known.

From the DE 10 2012 112 461 A1 is a switching valve, in particular for controlling a hydraulic fluid flow for adjusting a connecting rod length known. The switching valve has a tap element, in the surface of which a groove is formed. In addition, the switching valve has a sleeve-shaped connecting portion. The sleeve-shaped connecting portion has a first bore which connects the switching valve with a first hydraulic fluid line. The sleeve-shaped connecting portion further comprises a second bore which connects the switching valve with a second hydraulic fluid line. Moreover, the sleeve-shaped connecting portion on a vent hole, which connects the switching valve with a vent channel. The tapping element is arranged in the sleeve-shaped connecting portion and is selectively displaced into a first switching position or a second switching position, wherein in the first switching position, the groove formed in the tapping element connects the first hydraulic fluid line with the ventilation channel and wherein in the second switching position formed in the tapping element Groove connects the second hydraulic fluid line with the vent channel. The switching valve may be switched by an actuating pulse for displacing the tap member in the sleeve-shaped connecting portion by means of an electrically operated actuator.

Disclosure of the invention

An object of the invention is to provide a switching device with a hydraulic valve for controlling a hydraulic fluid, which has a compact design and is simple and robust to switch.

Another object is to provide a connecting rod with a hydraulic valve and a hydraulic valve for such a switching device, which has a compact design and is simple and robust to switch.

The above object is achieved according to one aspect of the invention with the features of independent claim 1.

Favorable embodiments and advantages of the invention will become apparent from the other claims, the description and the drawings.

 It is a switching device with a hydraulic valve for controlling a hydraulic fluid, in particular for switching an actuating piston in a connecting rod for a variable compression of an internal combustion engine, and proposed with at least one electric coil, wherein the hydraulic valve comprises a valve housing having a first control bore for a first channel and a second control bore for a second channel and having a vent hole for connection to a vent channel. Further, a movable piston is arranged in the valve housing, which is selectively displaceable at least in a first switching position or at least in a second switching position for acting on the first or second channel with hydraulic fluid. In this case, the at least one coil outside of the valve housing and the piston is arranged and the piston at least temporarily brought into operative connection with the at least one coil to move the piston from one switching position to the respective other switching position.

According to the invention, a hydraulic fluid is controlled by a switching device with a hydraulic valve, which is arranged in a connecting rod mechanism, which changes the compression ratio of an internal combustion engine via an actuating piston in the connecting rod mechanism. There are two fundamentally different valve concepts that can implement the function. On the one hand a bistable hydraulic valve, which is characterized by different Pressure levels of the hydraulic fluid switches. In another concept, the hydraulic valve is activated by pressure pulses. In the concept of the pressure pulse circuit, it may happen that, when a hydraulic valve does not switch on application of a pressure pulse, an asymmetry of the hydraulic pressure in the actuating mechanism arises. The concept of the circuit with pressure levels can cause problems when pressure fluctuations of the hydraulic fluid occur because it can lead to an unwanted switching of the hydraulic valve. Further problems represent a strong dependence of the switching behavior of the speed of the internal combustion engine.

These problems can be circumvented with the solution according to the invention by a mutual complementing of the advantages of both concepts with a hydraulic valve. The switching between two chambers of a control piston takes on a conventional hydraulic switching valve. However, the actuation of the hydraulic valve does not happen as with existing solutions by a mechanical coupling, but contactless by a magnetic force. Via at least one mounted in the vicinity of the crankshaft electric coil, a magnetic field is generated, which switches the hydraulic valve between two switching positions back and forth, which is designed for an interaction with the coil accordingly.

Advantages of the invention are a simple construction of the switching device with low component costs. Next results in a high durability of the hydraulic valve, since no wear caused by the switching function by the switching operation on non-contact way, since there is no tactile connection of the coil to the hydraulic valve. The hydraulic valve itself has little wear or tear due to large bearing surfaces of the piston.

The switching device is easy to install and has a safe operation with rotation of the crankshaft. The individual components required as the at least one electrical coil can be produced in a simple manner. The switching device has no dependence on the speed of the internal combustion engine. In addition, the switching capability remains unrestricted at start / stop operation of the internal combustion engine. Switching states are freely selectable. Operation of the internal combustion engine with cylinder deactivation is possible.

According to an advantageous embodiment, the at least one coil can be arranged at least temporarily in a longitudinal axis of the piston. In this way, the most favorable possible initiation of the magnetic force generated by the energization of the coil is made possible in the piston. At the same time tilting of the piston is avoided in the valve housing, so that the most secure and responsive switching function of the switching device is guaranteed.

According to an advantageous embodiment, the piston may at least partially comprise a hard magnetic material. The piston thus constitutes a permanent magnet, which enters into operative connection with the coil when energized therewith. The piston can be displaced by a magnetic force generated by the energization of the coil from one switching position to another switching position.

According to an advantageous embodiment, at times one coil may be arranged on opposite end faces of the piston at times. By such an arrangement, the magnetic force generated by the energization of the coil can be symmetrically aligned with the piston and act particularly effectively on the permanent magnetic piston. An axial alignment of the magnetic field of the coils is easy to produce by this arrangement, so that the movement of the piston in the valve housing can be done as smoothly as possible.

According to an advantageous embodiment, the hydraulic valve may be arranged in a connecting rod of an internal combustion engine, and the at least one coil connected to a crankcase of the internal combustion engine, so that the coil at least temporarily by the movement of the connecting rod on a crankshaft in the crankcase for switching the hydraulic valve itself is in operative connection with the hydraulic valve. The hydraulic valve can operate in such an arrangement arranged in the connecting rod actuating piston for a variable compression of an internal combustion engine when the hydraulic valve is at least temporarily brought into the magnetic field of the coil by the rotation of the crankshaft and thereby caused movement of the connecting rod, so that the hydraulic valve on this way can be switched. The coil itself can be fixed to the housing, for example, arranged on the crankcase or another location of the internal combustion engine or its surroundings.

According to an advantageous embodiment, two coils can be arranged on mutually opposite sides of the connecting rod for switching the hydraulic valve. In such an arrangement, the hydraulic valve can be brought in each case between the two coils during the movement of the connecting rod, for example so that the two end faces of the piston of the hydraulic valve are located between the two coils and so the permanent magnetic piston by a magnetic force generated by the coils of a switching position in the other switching position can be moved.

The invention relates in another aspect to a connecting rod having a hydraulic valve for controlling a hydraulic fluid, in particular for switching an actuating piston for variable compression of an internal combustion engine, and having at least one electric coil, wherein the hydraulic valve comprises a valve housing having a first control bore for a first Channel and a second control bore for a second channel and having a vent hole for connection to a vent channel, wherein in the valve housing a movable between at least two switching positions piston is arranged, which has at least partially a hard magnetic material. The hydraulic valve can operate in such an arrangement arranged in the connecting rod actuating piston for a variable compression of an internal combustion engine when the hydraulic valve is at least temporarily brought into the magnetic field of the coil by the rotation of the crankshaft and thereby caused movement of the connecting rod, so that the hydraulic valve on this way can be switched. The coil itself can be fixed to the housing, for example, arranged on the crankcase or another location of the internal combustion engine or its surroundings.

The invention relates in another aspect to a hydraulic valve for controlling a hydraulic fluid, in particular for switching an actuating piston of a connecting rod for variable compression of an internal combustion engine, with a valve housing having a first control bore for a first channel and a second control bore for a second channel and a vent hole for connection to a vent channel, wherein in the valve housing between at least two switch positions movable piston is arranged, which has at least partially a hard magnetic material. The piston can be moved in this way by a magnetic field generated in at least one electric coil, so that the hydraulic valve can control the flow of a hydraulic fluid.

 According to an advantageous embodiment, the first switching position and the second switching position may each be formed as stable layers of the hydraulic valve. Such a stable position of the hydraulic valve is of particular advantage when the hydraulic valve is brought by a movement of the connecting rod from the effective range of the coil. Thus, the hydraulic valve remains in a fixed switching position even in the absence of magnetic field, until the piston of the hydraulic valve is brought by the action of the magnetic field in another switching position.

According to an advantageous embodiment, the piston can be locked by means of a latching element in the first switching position in a first latching receptacle and be locked in the second switching position in a second latching receptacle. A stable position of the piston of the hydraulic valve can be achieved for example by such a latching element which can be locked in a latching receptacle and can be moved by the action of a magnetic force on the piston in a second latching receptacle.

According to an advantageous embodiment, the locking element can cooperate by means of a spring with the two formed in the piston locking receptacles. The locking element can be pressed by the spring in the locking receptacles, so that only when exceeding the spring force, the locking element is moved out of a locking receptacle and can engage in the other locking receptacle again.

Brief description of the drawings

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

 They show by way of example:

1 a plan view of a hydraulic valve according to the prior art in a first switching position;

2 a plan view of a hydraulic valve according to the prior art in a second switching position;

3 a section through a hydraulic valve according to the prior art in a first switching position, which illustrates a Verrastungsfunktion the piston;

4 a plan view of a switching device with a hydraulic valve and two coils according to an embodiment of the invention;

5 a connecting rod with a hydraulic valve according to an embodiment of the invention;

6 a schematic representation of a connecting rod assembly of a four-cylinder internal combustion engine with a switching device according to an embodiment of the invention; and

7 a schematic representation of the movement of a connecting rod with a switching device according to an embodiment of the invention.

Embodiments of the invention

In the figures, the same or similar components are numbered with the same reference numerals. The figures are merely examples and are not intended to be limiting.

1 shows a plan view of a hydraulic valve 10 according to the prior art in a first switching position S1. The hydraulic valve 10 includes a valve housing 16 in which there is a piston 12 emotional. The valve housing 16 has a first hole 17 on which the hydraulic valve 10 over a first channel 18 connects to a first hydraulic fluid line, and a second bore 19 on which the hydraulic valve 10 over a second channel 20 connects to a second hydraulic fluid line. Next, the valve housing 16 a vent hole 21 on which the hydraulic valve 10 via a ventilation channel 22 connects with a vent line. The piston 12 is cylindrical. The valve housing 16 has a hollow cylinder-shaped inner tread 36 on which the piston is on 12 is displaceable in the longitudinal axis L. The in the piston 12 trained groove 14 is T-shaped, wherein the groove 14 in the first switching position S1 in a region of the first bore 17 and the vent hole 21 and in the second switching position S2 in a region of the second bore 19 and the vent hole 21 is arranged. The vent hole 21 is in an area between the first and the second hole 17 . 19 arranged. In the first switching position S1 connects in the piston 12 trained groove 14 the first channel 18 with the venting channel 22 and in the second shift position S2, the one in the piston connects 12 trained groove 14 the second channel 20 with the venting channel 22 , In 1 is the switch position 1 shown.

2 shows a plan view of the hydraulic valve 10 according to the prior art in the second switching position S2, in which the in the piston 12 trained groove 14 the second channel 20 with the venting channel 22 combines.

3 shows a section through the hydraulic valve 10 According to the prior art in the first switching position S1, which is a Verrastungsfunktion the piston 12 illustrated. The first shift position S1 and the second shift position S2 are each as stable positions of the hydraulic valve 10 educated. The piston 12 is by means of a locking element 24 in the first switching position S1 in a first latching receptacle 26 lockable and in the second switching position S2 in a second locking receptacle 27 lockable. The locking element 24 acts by means of a spring 25 with the two in the flask 12 trained snap shots 26 . 27 together. The piston 12 has two groove-shaped locking receptacles 26 . 27 in which a locking element 24 can engage and so the piston 12 opposite the valve housing 16 can lock. The locking element 24 is doing by a spring 25 held and against the locking shots 26 . 27 pressed. Will the piston 12 in its longitudinal axis L in the direction of the first end face 28 pressed, so when the spring force is exceeded, the locking element 24 from the first snap-in receptacle 26 disengage and in the second locking receptacle 27 engage. The piston 12 is then held in the second switching position S2.

In 4 is a plan view of a switching device 100 with a hydraulic valve 10 and two coils 30 . 32 illustrated according to an embodiment of the invention. The switching device 100 with a hydraulic valve 10 for controlling a hydraulic fluid, in particular for switching an actuating piston 48 in a connecting rod 40 for a variable compression of an internal combustion engine, has two coils 30 . 32 on. The hydraulic valve 10 includes a valve housing 16 , which is a first control bore 17 for a first channel 18 and a second control bore 19 for a second channel 20 has and a vent hole 21 for connection to a ventilation duct 22 having. In the valve housing 16 is a moving piston 12 arranged, which optionally at least in a first switching position S1 or at least in a second switching position S2 for acting on the first or second channel 18 . 20 is displaceable with hydraulic fluid. The spools 30 . 32 are outside of the valve body 16 and the piston 12 arranged, the piston 12 at least temporarily with at least one coil 30 . 32 is brought into operative connection to the piston 12 to move from one switching position S1, S2 in the respective other switching position S2, S1. The piston 12 includes at least partially a hard magnetic material, so that it represents a permanent magnet and by a when energizing the coils 30 . 32 generated magnetic field is attracted or repelled and thus moves in the longitudinal axis L. The spools 30 . 32 are at least temporarily in the longitudinal axis L of the piston 12 , preferably on opposite end faces 28 . 29 of the piston 12 arranged.

In 5 is a connecting rod 40 an internal combustion engine with a hydraulic valve 10 illustrated according to an embodiment of the invention. The connecting rod 40 has a hydraulic valve 10 for controlling a hydraulic fluid, in particular for switching an actuating piston 48 for a variable compression of an internal combustion engine, as well as at least one electric coil 30 . 32 (not shown). The hydraulic valve 10 , whose individual components in 5 are not visible as they are inside the connecting rod 40 sit, includes a valve housing 16 , which is a first control bore 17 for a first channel 18 and a second control bore 19 for a second channel 20 has and a vent hole 21 for connection to a ventilation duct 22 wherein, in the valve housing 16 a between at least two switching positions S1, S2 movable piston 12 is arranged, which has at least partially a hard magnetic material.

The hydraulic valve 10 is in the connecting rod 40 arranged. The at least one coil 30 . 32 is with a crankcase 62 (not shown) of the internal combustion engine, so that the coil 30 . 32 through the movement of the connecting rod 40 on a crankshaft 60 in the crankcase 62 at least temporarily for switching the hydraulic valve 10 in operative connection with the hydraulic valve 10 located. This process is in 7 to see schematically. For switching the hydraulic valve 10 are the two coils 30 . 32 Conveniently on opposite sides of the connecting rod 40 arranged.

The connecting rod 40 has a hole 66 for receiving a cylinder piston bearing. Next is a piston guide inside the connecting rod 46 for receiving a control piston 48 arranged over one in the hole 66 arranged eccentric as a cylinder piston bearing a different stroke of a cylinder piston 54 and thus can cause a variable compression of an internal combustion engine. The connecting rod 40 itself is about a connecting rod bearing 42 connected to a crankshaft. In the connecting rod bearing 42 is a channel 52 arranged to supply the hydraulic fluid.

6 shows a schematic representation of a connecting rod assembly of a four-cylinder internal combustion engine with a switching device 100 according to an embodiment of the invention. The four connecting rods 40 are with a schematically illustrated crankshaft 60 connected and carry at its opposite end in each case a likewise schematically illustrated cylinder piston 54 , Inside the connecting rod 40 is each a hydraulic valve 10 arranged, which depends on the position of the connecting rod 40 in the sphere of action of both sides of the connecting rod 40 arranged coils 30 . 32 is brought. Inside the connecting rod 40 at least one runs in each case through the hydraulic valve 10 controlled actuator piston 48 , the different strokes of the cylinder pistons 54 and thus can cause a different compression of the internal combustion engine.

In 7 is a schematic representation of the movement of a connecting rod 40 with a switching device 100 to see according to an embodiment of the invention. The one with the crankshaft 60 connected connecting rods 40 moves in the direction of rotation 50 the crankshaft 60 in a rotational movement 64 , It will be in the connecting rod 40 arranged hydraulic valve 10 through the effective range of the two on both sides of the connecting rod 40 arranged electric coils 30 . 32 guided. An energization of the coils 30 . 32 creates a magnetic field associated with the permanent magnet of the piston 12 of the hydraulic valve 10 interacts and thus the piston 12 moved in its longitudinal axis L and so the hydraulic valve 10 on. A switching of the hydraulic valve 10 causes a longitudinal movement of the inside of the connecting rod 40 arranged adjusting piston 48 whose movement turn one in a bore 66 arranged and with the actuator piston 48 connected eccentric 58 adjusted. The eccentric 58 is doing one with a piston pin bearing eye 56 stored cones 68 of the cylinder piston 54 connected. About the eccentric 58 so can a different stroke of the cylinder piston 54 be effected in a cylinder bore and thus a variable compression of the internal combustion engine.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012112461 A1 [0003]

Claims (11)

Switching device ( 100 ) with a hydraulic valve ( 10 ) for controlling a hydraulic fluid, in particular for switching an actuating piston ( 48 ) in a connecting rod ( 40 ) for a variable compression of an internal combustion engine, and with at least one electrical coil ( 30 . 32 ), whereby the hydraulic valve ( 10 ) a valve housing ( 16 ) comprising a first control bore ( 17 ) for a first channel ( 18 ) and a second control bore ( 19 ) for a second channel ( 20 ) and having a vent hole ( 21 ) for connection to a ventilation channel ( 22 ), wherein in the valve housing ( 16 ) a movable piston ( 12 ) which is optionally arranged at least in a first switching position (S1) or at least in a second switching position (S2) for acting on the first or second channel ( 18 . 20 ) is displaceable with hydraulic fluid, wherein the at least one coil ( 30 . 32 ) outside of the valve housing ( 16 ) and the piston ( 12 ) is arranged and the piston ( 12 ) at least temporarily with the at least one coil ( 30 . 32 ) is operatively connected to the piston ( 12 ) to move from one switching position (S1, S2) in the respective other switching position (S2, S1). Switching device according to claim 1, wherein the at least one coil ( 30 . 32 ) at least temporarily in a longitudinal axis (L) of the piston ( 12 ) is arranged. Switching device according to claim 1 or 2, wherein the piston ( 12 ) comprises at least partially a hard magnetic material. Switching device according to one of the preceding claims, wherein at times a respective coil ( 30 . 32 ) on opposite end faces ( 28 . 29 ) of the piston ( 12 ) is arranged. Switching device according to one of the preceding claims, wherein the hydraulic valve ( 10 ) in a connecting rod ( 40 ) of an internal combustion engine, and wherein the at least one coil ( 30 . 32 ) with a crankcase ( 62 ) of the internal combustion engine is connected so that the coil ( 30 . 32 ) by the movement of the connecting rod ( 40 ) on a crankshaft ( 60 ) in the crankcase ( 62 ) at least temporarily for switching the hydraulic valve ( 10 ) in operative connection with the hydraulic valve ( 10 ) is located. Switching device according to claim 5, wherein for switching the hydraulic valve ( 10 ) two coils ( 30 . 32 ) on opposite sides of the connecting rod ( 40 ) are arranged. Connecting rod ( 40 ) with a hydraulic valve ( 10 ) for controlling a hydraulic fluid, in particular for switching an actuating piston ( 48 ) for a variable compression of an internal combustion engine, and with at least one electrical coil ( 30 . 32 ), whereby the hydraulic valve ( 10 ) a valve housing ( 16 ) comprising a first control bore ( 17 ) for a first channel ( 18 ) and a second control bore ( 19 ) for a second channel ( 20 ) and having a vent hole ( 21 ) for connection to a ventilation channel ( 22 ), wherein in the valve housing ( 16 ) between at least two switching positions (S1, S2) movable piston ( 12 ) is arranged, which has at least partially a hard magnetic material. Hydraulic valve ( 10 ) for controlling a hydraulic fluid, in particular for switching an actuating piston ( 48 ) of a connecting rod ( 40 ) for a variable compression of an internal combustion engine, with a valve housing ( 16 ), which has a first control bore ( 17 ) for a first channel ( 18 ) and a second control bore ( 19 ) for a second channel ( 20 ) and having a vent hole ( 21 ) for connection to a ventilation channel ( 22 ), wherein in the valve housing ( 16 ) between at least two switching positions (S1, S2) movable piston ( 12 ) is arranged, which has at least partially a hard magnetic material.  Hydraulic valve according to claim 8, wherein the first switching position (S1) and the second switching position (S2) are each formed as stable positions of the hydraulic valve. Hydraulic valve according to claim 8 or 9, wherein the piston ( 12 ) by means of a latching element ( 24 ) in the first switching position (S1) in a first latching receptacle ( 26 ) is lockable and in the second switching position (S2) in a second latching receptacle ( 27 ) is lockable. Hydraulic valve according to claim 10, wherein the latching element ( 24 ) by means of a spring ( 25 ) with the two in the piston ( 12 ) formed locking recesses ( 26 . 27 ) cooperates.

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