DE102010061360A1 - Reversing valve for controlling engine oil flow in spark ignition petrol engine of passenger motor car, has two working chambers brought in fluid communication with engine inner space via fluid conduits - Google Patents

Abstract

The valve (110) has two working chambers (82, 92) brought in fluid communication with an engine inner space (120) via fluid conduits (86, 96), where the valve is displaced between two switching positions by applying activation pressure (I) i.e. engine oil pressure, on the valve. The valve is coupled to a spring such that the actuation of the valve is carried out when the activation pressure exceeds a predetermined threshold pressure level. The two workspaces are filled with fluid i.e. engine oil, through hydraulic passages (85, 95). The spring is arranged at an end of a control piston. An independent claim is also included for a combustion engine comprising a connecting rod arrangement.

Description

The present invention relates to a switching valve for controlling a fluid flow and an internal combustion engine having such a switching valve.

Although applicable to any vehicle, the present invention and the underlying problem with respect to a passenger car will be explained in more detail.

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, the compression ratio, however, may only be selected so high that so-called "knocking" of the internal combustion engine is avoided during full-load operation. However, for the much more frequently occurring partial load range of the internal combustion engine, ie with low cylinder filling, the compression ratio with higher values could be selected without "knocking" occurring. The important part load range of an internal combustion engine can be improved if the compression ratio is variably adjustable. Various systems are described for adjusting the compression ratio.

The DE 10 2005 055 199 describes a system in which the connecting rod length is variably adjustable. The variation of the connecting rod length is carried out by a rotation of an eccentric connecting rod eye. The rotation of the connecting rod eye is initiated by the action of mass and gas forces of the internal combustion engine, wherein the rotational movement is assisted by acted upon with engine oil piston in the connecting rod. To control the rotational movement of the eccentric connecting rod each one of the piston is pressurized with engine oil, while the other piston is depressurized. The pistons are controlled via a 3/2-way valve. To switch the 3/2-way valve, this must be operated mechanically. For this purpose, a complex solution of slide tracks, switching and push rods, which are driven by an electric motor, for example, provided from outside. However, this requires extensive changes to the internal combustion engine.

Thus, the present invention has for its object to provide an improved changeover valve, which eliminates the disadvantages mentioned above.

This object is achieved by a switching valve with the features of claim 1 and / or by an internal combustion engine with the features of claim 7.

Accordingly, it is provided:
A switching valve, in particular for controlling a fluid flow, wherein the switching valve is selectively displaceable in a first and a second switching position, whereby in each case a first working space or a second working space can be brought into fluid communication with a volume.

An internal combustion engine having an adjustable compression ratio, comprising: such a switching valve; and a connecting rod assembly with a arranged in a connecting rod eye and / or a Hublagerauge hydraulically adjustable eccentric means for adjusting an effective connecting rod length, wherein an adjustment of the eccentric means of the switching valve is controllable.

The basic idea of the present invention is to provide a switching valve which can be displaced optionally into a first and a second switching position, whereby a respective first working space or a second working space can be brought into fluid communication with a volume.

In the dependent claims are advantageous refinements and improvements of the specified in claim 1 switching valve or specified in claim 7 internal combustion engine.

According to a preferred development, the switching valve has a fluid groove for establishing the fluid connection of the first or second working space with the volume. This advantageously allows a simple production of the changeover valve and at the same time a simple switching from the first switching position to the second switching position.

According to a further preferred embodiment, a displacement of the switching valve in the respective switching position by an actuating pressure or switching pressure on the switching valve can be triggered, whereby a defined and controlled displacement is possible. The terms "operating pressure" and "switching pressure" are to be used synonymously.

According to a further preferred embodiment, the actuation pressure can be applied by a fluid pressure. As a result, the displacement of the switching valve in an easily controllable manner executable.

According to a further preferred development, in each case a specific fluid pressure can be applied for displacing the switching valve into the first and the second switching position. This allows a reliable and safe switching from the first to the second switching position and vice versa, whereby the reliability of the switching valve increases, since the switching depends on a certain predeterminable and controllable pressure value.

According to a further preferred embodiment, the switching valve is formed by means of a spring device coupled to the switching valve such that actuation of the switching valve takes place only at an actuating pressure above a predetermined pressure threshold value. This reliably prevents accidental switching of the switching valve, thereby increasing its reliability.

According to a further preferred development, the changeover valve is integrated in the connecting rod arrangement, in particular in a region of the lifting bearing eye, whereby the changeover valve takes up only small installation space. As a result, the range of application of the changeover valve is advantageously extended.

According to a preferred embodiment, the actuation pressure can be applied by an engine oil pressure, the combustion engine having means, for example a controllable oil pump or a pressure accumulator or an additional oil pump, for permanently increasing the engine oil pressure. This advantageously makes it possible to integrate the changeover valve into existing engine oil systems, thereby widening the range of use of the changeover valve.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the attached schematic figures of the drawings.

From the figures shows:

1 Cross-sectional views of a connecting rod-piston assembly with a switching valve according to a preferred embodiment of the present invention in various operating conditions;

2 a detailed view of the connecting rod-piston assembly in an in 1 shown operating state;

3a / b is a detailed view of a switching valve of the connecting rod-piston assembly 1 the preferred embodiment of the present invention;

4a an engine load / speed shift diagram and an oil pressure / speed shift diagram for the changeover valve of the preferred embodiment of the present invention;

5a / b is a detailed view of a switching valve of the connecting rod-piston assembly 1 in a further preferred embodiment of the present invention; and

6 an oil pressure / speed shift diagram for the switching valve of the further preferred embodiment of the present invention.

In the figures of the drawings, the same reference numerals designate the same or functionally identical components, unless indicated otherwise.

1 shows for a change-over valve according to the invention a connecting rod-piston arrangement 10 in two operating states A and B, wherein in operating state B, the connecting rod-piston assembly 10 is shown only partially to illustrate the essential difference between operating state A and B.

For better clarity, an inventive switching valve is initially omitted here. The connecting rod-piston arrangement 10 consists of a connecting rod 20 with a crank eye 30 , With the connecting rod 20 is a piston 40 coupled, which about a center axis 45 a connecting rod bearing eye 46 is pivotable, but in an eccentric manner, since a midpoint axis 50 a piston pin bore 60 of the piston 40 from the midpoint axis 45 of the connecting rod bearing eye 46 is spaced. By an eccentric device 65 with an eccentric body 70 and on the eccentric body 70 hinged eccentric rods 80 and 90 can be a position of the piston 40 relative to the connecting rod 20 be changed so as to produce a higher or lower compression as needed.

The operation of the eccentric rods 80 . 90 will be below with reference to 2 explained. However, in 1 to recognize that depending on a position of the eccentric rods 80 . 90 in the designated A operating state of the piston 40 relative to the connecting rod 20 protrudes further, and thus a compression is maximum, and in B designated operating state of the piston 40 relative to the connecting rod 20 is closer, and thus a compression is minimal.

In 2 is the connecting rod 20 shown in cross section, in turn, the Hublagerauge 30 , the connecting rod eye 46 with its midpoint axis 45 , the eccentric body 70 and the eccentric rods hinged thereto 80 and 90 can be seen. The eccentric rods 80 . 90 are with pistons 81 respectively. 91 in a first workroom 82 or in a second workspace 92 feasible. The workrooms 82 . 92 can via hydraulic lines 85 . 95 be filled with a fluid, such as engine oil, alternately, so that when one of the working spaces 82 . 92 is acted upon by fluid, the piston located therein 81 respectively. 91 is displaced accordingly, and thus eccentric rod 80 respectively. 90 the eccentric body 70 pivoted, which has a change in the piston position relative to the connecting rod and thus a changed compression result.

Im in 2 example shown is workspace 92 subjected to fluid while working space 82 is empty.

The in 2 shown state corresponds to the state B in 1 because an effective length l _eff between a midpoint axis 100 of the stroke bearing eye 30 and the midpoint axis 50 the (not shown here) piston pin bore is minimal.

So that an alternating filling of the work spaces 82 respectively. 92 can be done is a switching valve 110 provided, which in 2 is shown only schematically, and in detail with reference to 3 should be explained.

In principle, the change-over valve ensures 110 for being the first workroom 81 via a fluid line 86 or the second workspace 92 via a fluid line 96 alternatively with one volume 120 which, for example, the engine compartment (ie crankshaft housing) and / or the stroke bearing of the Hubagerauges 30 corresponds, is brought into fluid communication. That is, the changeover valve 110 can, as in 2 is shown, the fluid line 96 lock, leaving the work space 92 with fluid through the fluid line 95 is fillable. At the same time, the fluid line 86 of the workroom 82 via the changeover valve 110 open so that over the fluid line 85 in the workroom 82 flowing fluid again via a vent hole not shown in the volume 120 can escape, being the volume 120 the engine compartment or the stroke bearing or both can be. Thus, in the first working space 82 do not apply pressure to the eccentric rod 80 to move. As a corresponding vent hole for the second working space 92 through the switching valve 110 Locked, this can be done via fluid line 95 Incoming fluid does not escape, and it builds a pressure in the second working space 92 on which the eccentric rod 90 can shift, and thus the eccentric body 70 pivoted with the coupled thereto (not shown here) piston.

By a in 2 shown arrow I is indicated that an operating pressure must be applied to the switching valve, so that the switching valve 110 moves from one switch position to another, so corresponding to a fluid connection of the work spaces 82 . 92 with the volume 120 or not. If the change-over valve is displaced into a switching position, the corresponding pressure must be present permanently in order to hold the change-over valve in this switching position.

3a and 3b each show a detailed view of the switching valve 110 out 2 in a first switching position ( 3a ) and in a second switching position ( 3b ). It should be noted that the better representability because of in 3a and 3b shown switching valve 110 by 90 ° with respect to the representation of in 2 schematically shown switching valve 110 is turned.

The following description refers to both 3a as well 3b :
The changeover valve 110 sits in a valve block 130 of in 2 shown connecting rod 20 , and is in a valve hole 140 to the right and left, based on the 3a respectively. 3b , relocatable.

Furthermore, the changeover valve comprises 110 a control piston 190 , At one end of the control piston 190 there is a spring device 200 in a recess 201 , wherein the spring device 200 with the control piston 190 is coupled and this to the right (relative to the 3a and 3b ). Around the spool 190 runs a fluid groove 210 , which depending on the switching position of the switching valve 110 with fluid lines 96 . 96 ' respectively. 86 . 86 ' can be brought into fluid communication. Here are the fluid lines 86 . 96 in the 2 shown fluid lines 86 . 96 , and the fluid lines 86 ' and 96 ' are the above-mentioned but not previously shown vent holes to the engine compartment out. This in 3b Example shown thus shows the in 2 shown state where the first working space 82 with fluid line 86 through the switching valve 110 in fluid communication with the engine compartment or volume 120 stands, via vent hole or fluid line 86 ' , In this switching position of the changeover valve 110 is the fluid line 96 through the control piston 190 locked accordingly, the second working space 92 in 2 is not in fluid communication with the volume 120 and therefore can be pressurized with fluid while the first working space 82 (please refer 2 ) is depressurized.

As in 3a and 3b each indicated by an arrow designated I (see also 2 ), by an actuating pressure I along a fluid line 97 for shifting the switching valve 110 in a switching position, a pressure on the switching valve 110 exerted, wherein the pressure is controlled by an oil pressure of the internal combustion engine. However, additional pressure generating devices are also conceivable.

In 3b the actuating pressure I acts against a force of the spring device 200 , so starting from the position of the changeover valve 110 in 3b the changeover valve 110 in the in 3a shown shifted position. For the opposite case, ie from the position in 3a in the position in 3b , the operating pressure I must be correspondingly smaller than the force of the spring device 200 be. In 3a is a switching position 1 with ε = low shown, while in 3b a switching position 2 with ε = high is shown.

As an explanation to complement the 4a and 4b serve.

4a shows an example of an engine load / speed diagram in which map areas for compression ratios ε for low compression (ε = low) and high compression (ε = high) are plotted. The compression ratio ε results from the quotient of (displacement + compression space) and compression space. A solid line curve a represents the maximum threshold for engine load _versus speed. A dashed line curve p _me1 indicates an effective average engine load resulting from the effective mean engine pressure in the engine compartment, multiplied by the displacement of the engine. Below the curve p _me1 is a map with ε = high, with a high compression (ε = high) in a speed range of about 1000 revolutions / min up to a speed threshold n2 at slightly less than 4000 revolutions / min, ie in the partial load range , automatically results in "normal" oil pressure gradients. Also, with respect to 4b , with a suitable choice of a switching pressure threshold p2 the compression by the "normal" oil pressure for speeds n greater than a speed threshold n1 independently on ε = low controlled. In order to reduce the compression in the upper performance range, the oil pressure level of the engine is durable to a pressure p greater than a switching pressure p _switching raised (see 4b ). Related to 3a Thus, p ≥ p2, and based on 3b p <p1.

Further with reference to 4a can be switched for the speed range from n2 but alternatively to the top - depending on the engine load - either in a map with low compression (ε = low) or in a map with high compression (ε = high), the two maps in 4a are separated from each other by a predefinable engine load switching threshold M.

This in 5a and 5b in each case different positions shown switching valve 110 is essentially the same as in 3a and 3b shown switching valve 110 , but with the difference that the fluid lines 86 . 86 ' and 96 . 96 ' regarding 3a and 3b are reversed. In this case, the in 5a shown switching position 1 a high compression (ε = high), and the in 5b shown switching position 2 corresponds to a low compression (ε = low). For this embodiment, the compression would be at an oil pressure corresponding 6 always low. In order to increase the compression in the partial load range, the oil pressure level would have to be raised permanently to a pressure p greater than the switching pressure p ₂ .

LIST OF REFERENCE NUMBERS

10

Connecting rod-piston arrangement

20

pleuel

30

Hublagerauge

40

piston

45

Center point pin rod eye

46

Pleuellagerauge

50

Center point of the piston pin bore

60

Piston pin bore

65

eccentric

70

eccentric

80

eccentric

81

piston

82

first working space

85

fluid line

86

fluid line

86 '

vent hole

90

eccentric

91

piston

92

second workspace

95

fluid line

96

fluid line

96 '

vent hole

97

fluid line

100

Center point axle bearing eye

110

switching valve

120

Volume / engine compartment

130

manifold

140

valve bore

190

spool

200

spring means

201

Recess for spring device

210

fluid groove

Ip1

actuating pressure

Ip2

actuating pressure

a, b, c

curves

M

Engine load switching threshold

n ₂

Speed threshold

p _engine

pressure level

_partnership

pressure level

p _max

pressure level

p1, p2

pressures

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 102005055199 [0004]

Claims (9)

Changeover valve ( 110 ) for controlling a fluid flow, wherein the switching valve ( 110 ) is selectively displaceable in a first and a second switching position, whereby in each case a first working space ( 82 ) or a second workspace ( 92 ) with a volume ( 120 ) can be brought into fluid communication. Changeover valve ( 110 ) according to claim 1, characterized in that the switching valve ( 110 ) a fluid groove for establishing the fluid connection of the first and second working space ( 82 . 92 ) with the volume ( 120 ) having. Changeover valve ( 110 ) according to claim 1 or 2, characterized in that a displacement of the switching valve ( 110 ) in the respective switching position by an actuating pressure (I) on the switching valve ( 110 ) is triggered. Changeover valve ( 110 ) according to claim 3, characterized in that the actuating pressure (I) can be applied by a fluid pressure. Changeover valve ( 110 ) according to claim 4, characterized in that for displacing the switching valve ( 110 ) in the first and the second switching position ( 82 . 92 ) in each case a certain fluid pressure can be applied. Changeover valve ( 110 ) according to one of claims 4 or 5, characterized in that the switching valve ( 110 ) by means of a with the switching valve ( 110 ) coupled spring device ( 200 ) is designed such that an actuation of the switching valve ( 110 ) takes place only at an actuation pressure (I) above a predetermined pressure threshold value. An internal combustion engine having an adjustable compression ratio, comprising: a switching valve ( 110 ) according to any one of the preceding claims; and a connecting rod assembly ( 10 ) with one in a connecting rod eye ( 46 ) and / or a bung eye ( 30 ) arranged hydraulically adjustable eccentric ( 65 ) for adjusting an effective connecting rod length (l _eff ), wherein an adjustment of the eccentric ( 65 ) by means of the switching valve ( 110 ) is controllable. Internal combustion engine according to claim 7, characterized in that the switching valve ( 110 ) in the connecting rod assembly ( 10 ), in particular in a region of the Hubagerauges ( 30 ) is integrated. Internal combustion engine according to claim 7 or 8, characterized in that the actuating pressure (I) can be applied by an engine oil pressure, wherein the internal combustion engine having means, such as a controllable oil pump or a pressure accumulator or a booster oil pump, for increasing the engine oil pressure.

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