DE102016202430A1 - Check valve and control system - Google Patents

Abstract

The invention relates to a check valve (27) for a control system of a device for varying the compression ratio of a cylinder unit of a reciprocating internal combustion engine, comprising a ball (29) mounted in a housing (28) and held in the closed position by a compression spring (30). The compression spring (30) is held by a spring holder (31) arranged in the housing (28). Furthermore, the invention relates to a control system for actuating two interacting with an adjusting actuator piston for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the control system according to the invention comprises check valves.

Description

Field of the invention

The invention relates to a check valve for a control system of a device for varying the compression ratio of a cylinder unit of a reciprocating internal combustion engine, comprising a ball mounted in a housing which is held by a compression spring in the closed position. Furthermore, the invention relates to a control system for actuating two interacting with an adjusting actuator piston for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element is adjustable by the engine forces of the reciprocating internal combustion engine in two different positions in which guided in the support cylinders single-acting Control piston, which together with the support cylinders each form a pressure chamber, are in a retracted or extended position, wherein the pressure chambers are each connected via an oil supply line, in which a check valve according to the invention is arranged with an oil supply, wherein from the two pressure chambers outgoing oil return lines a switching valve are connected, via which the oil return lines are optionally pressure relieved.

State of the art

With the compression ratio of a reciprocating internal combustion engine ε the ratio of the volume of the entire cylinder chamber to the volume of the compression chamber is designated. By increasing the compression ratio of the efficiency of the reciprocating internal combustion engine can be increased, resulting in a total of a reduction in fuel consumption results in the same performance of the reciprocating internal combustion engine. However, it should be noted that in spark-ignited reciprocating internal combustion engines with an increase in the compression ratio in full load operation, the tendency to knock increases.

The knocking is an uncontrolled self-ignition of the fuel-air mixture. On the other hand, in the partial load operation in which the charge is lower, the compression ratio may be increased to improve the corresponding partial load efficiency without the aforementioned knocking occurring. As a result, it is expedient to operate the reciprocating internal combustion engine in part-load operation with a relatively high compression ratio and in full load operation with a reduced compression ratio compared to this.

A change in the compression ratio is also particularly advantageous for supercharged reciprocating internal combustion engines with spark ignition, as these overall in terms of charging a low compression ratio is given, and to improve the thermodynamic efficiency in unfavorable areas of a corresponding engine map, the compression is to increase. In addition, it is possible to change the compression ratio generally depending on other operating parameters of the reciprocating internal combustion engine, such as. of driving conditions of the motor vehicle, operating points of the internal combustion engine, signals of a knock sensor, exhaust gas values, etc.

Among other things, devices are known from the prior art, which make an adjustment of the distance between a crank pin of a crankshaft and a piston pin. These are different devices, namely those with which the position of the piston relative to the connecting rod is variable, or those that make a change in position of the connecting rod relative to the crankshaft. In the case of the first-mentioned devices, the connecting rod is connected to the piston via an adjustable eccentric provided on the connecting rod eye, in which a piston pin bearing and a piston pin are arranged. In the further mentioned devices, an adjustable eccentric crank shaft side is thus provided at the connecting rod bearing eye, in which case this eccentric surrounds the connecting rod bearing.

The corresponding eccentric is adjusted by the engine forces occurring in the cylinder unit between the connecting rod on the one hand and the piston pin or the crank pin on the other hand, ie mass and load forces. In the working cycle of the cylinder unit, the acting forces change continuously. It is particularly useful for a device provided on the piston pin bearing device to connect the eccentric with two actuating pistons which act on this to its rotation and support via tabs. Thus, the rotational movement supported by the actuating piston and a provision of the eccentric, which can occur due to the force transmitted to the eccentric with different directions of force forces can be avoided.

A control system for actuating two cooperating with an adjusting actuator piston for a device for changing a compression ratio of a reciprocating internal combustion engine of the type described in the preamble of claim 1 is known from the DE 10 2012 112 434 A1 known. Thereafter, a arranged in a connecting rod eye of a connecting rod eccentric is provided with an eccentric piston pin bore, wherein the eccentric has diametrically extending tabs on which attack on eccentric rods pistons. Guide cylinders, which receive these pistons, are supplied with hydraulic fluid from a connecting rod bearing via hydraulic fluid lines, in each of which a backflow preventive check valve is arranged.

In addition to this hydraulic fluid line, a further hydraulic fluid line is connected to each of the two guide cylinder, which leads to a switching valve. The switching valve, which consists of a sleeve-like housing and a control element called Abgriffselement, selectively connects one of the hydraulic fluid lines with a designated as a vent passage tank port through which the hydraulic fluid can be discharged without pressure into an oil pan of the reciprocating internal combustion engine.

Disclosure of the invention

It is an object of the present invention to improve the function and design of the check valves.

This object is achieved by the features of the characterizing part of independent claim 1. Advantageous embodiments are given in the claims dependent thereon, which in themselves or in various combinations with each other may constitute an aspect of the invention.

Thereafter, the check valve should consist of a mounted in a separate housing ball, which is held by a spring in its closed position, wherein the spring is held by a spring holder disposed in the housing. This makes it possible to pre-assemble each check valve and then pressed as a unit in the oil supply line.

As a spring holder, a multiply bent wire is preferably used, which is bent so that a portion of the wire can simultaneously serve as a stop for the opening stroke of the ball. Thus, two functions are fulfilled by a component, namely to act once as a pen and the other as stroke limitation. As a wire, a simple round wire can be used. However, other cross-sectional shapes are conceivable. This is an inexpensive material available. The wire is brought into the desired shape by simple bending operations. As a result, there are no restrictions due to special shaping processes. The bending process is a fast and inexpensive manufacturing process and does not require expensive special machines. Another advantage of using a wire is that it has only a small cross section, so that it does not oppose any appreciable resistance of the hydraulic fluid flowing through.

It is advantageous if the two ends of the wire and a first central region lie in one plane. Then these areas can be used to attach the wire to the housing and at the same time as a spring plate.

The attachment of the wire can be done through openings in the housing. Here is the wire for easier assembly of spring wire. Then, for assembly, the two ends and preferably also the first central area only have to be pressed together and then snapped as it were under the spring action in the housing openings. As a result, a three-point attachment is achieved while providing a sufficiently large surface for holding the compression spring.

Alternatively, recesses or recesses may be incorporated in the housing edge, which receive the end regions and preferably also the first central region. To fix the position then the housing must be pressed into the respective hydraulic supply line, that the recesses or depressions are closed by a shoulder in the hydraulic supply line. This solution thus saves the installation of separate openings in the housing wall.

A simple way to limit the opening stroke of the ball, is that a second central region of the wire is angled in the direction of the ball. In this case, then only one more easy to produce bending process must follow the first bending process. This is also inexpensive to realize. In addition, the running within the spring second central area requires no additional space. Also, it can be prevented lateral migration of the spring. This area also serves as the lead at the same time.

If a third central region of the wire is also bent in the direction of the ball, we obtain two parallel stops for the ball. Tilting or pinching the ball between stop and spring is thus excluded. This also prevents buckling of the spring inwards, since the two central regions can guide the spring almost over its entire inner circumference.

In this case, it is advantageous to let the second and third middle regions run parallel. This gives you two closely spaced stop areas. The flow resistance for the hydraulic fluid is thus increased only negligible.

The invention is not limited to the specified combination of the features of independent claim 1 with the claims dependent thereon. In addition, there are further possibilities of combining individual features, in particular if they arise from the patent claims, the following description of the exemplary embodiments or directly from the figures. In addition, the reference of the claims to the figures by the use of reference numerals is not intended to limit the scope of the claims to the illustrated embodiment examples.

Short description of the drawing

For further explanation of the invention reference is made to the drawing, in which several different embodiments are shown in simplified form. Show it:

1 a schematic representation of a consisting of a working piston and a connecting rod unit with an adjusting element, via which the position of the working piston relative to the connecting rod is variable on a piston pin,

2a , b is a longitudinal section through a check valve in the closed and in the open state with a first embodiment of a spring holder,

3 a perspective view of the check valve after 2 from above,

4a , b is a perspective view of the first embodiment of the spring holder from above and below,

5a , b is a longitudinal section through a check valve in the closed and in the open state with a second embodiment of a spring holder,

6 a perspective view of the check valve after 5 from above,

7a , b is a perspective view of the second embodiment of the spring holder from above and below.

Detailed description of the drawing

In the 1 is with 1 a connecting rod for a cylinder unit of a reciprocating internal combustion engine referred to, which consists of a Pleueloberteil 2 and a connecting rod base 3 consists. The connecting rod upper part 2 and the connecting rod base 3 together form a connecting rod eye 4 over which the connecting rod 1 is mounted on a crank pin, not shown, a crankshaft. At its other end is the connecting rod shell 2 with a connecting rod eye 5 provided, in which about as eccentric 6 trained adjustment 7 and a not-shown piston pin bearing a piston pin 8th is arranged. About this rotatably guided in the piston pin bearing piston pin 8th is a working piston 9 a cylinder unit of the reciprocating internal combustion engine to the adjusting element 7 the rotation of which leads in one direction to set a relatively low compression ratio and its rotation in the opposite direction to set a higher compression ratio.

The eccentric 6 is characterized by in the cylinder unit between the connecting rod 1 on the one hand and the piston pin 8th or the crank pin on the other hand occurring engine forces, ie mass and load forces adjusted. In the working cycle of the cylinder unit, the acting forces change continuously. The eccentric 6 has diametrically extending tabs 10 and 11 on, each via piston rods 12 and 13 with single-acting actuator piston 14 and 15 are connected. The adjusting pistons 14 and 15 grip on the aforementioned components on the eccentric 6 to twist and support it. Thus, by the adjusting piston 14 and 15 the rotational movement of the eccentric 6 supports and its provision, due to different directions of force on the eccentric 6 transmitted forces can occur can be avoided.

The adjusting pistons 14 and 15 are in support cylinders 16 and 17 guided and together with these pressure chambers 18 and 19 in which serving as a hydraulic medium lubricating oil of the reciprocating internal combustion engine from a in the connecting rod eye 4 arranged connecting rod bearings 20 via oil supply lines 21 and 22 can flow in. Furthermore, it goes from each of the pressure chambers 18 and 19 an oil return line 23 respectively. 24 from, like, from the 1 emerges, both in a receiving bore 25 open for a switching valve. From the connecting rod bearing 20 also carries a control line 26 to the receiving hole 25 , In the two oil supply lines 21 and 22 is one - not visible here - check valve 27 installed, the structure of which is described below with reference to 2 to 7 is explained in more detail.

In 2a , b is a longitudinal section through the inventively constructed check valve 27 shown. It consists of a housing 28 , a ball 29 , a compression spring 30 as well as the pen holder 31 , The housing is pot-shaped and open at the top. It has at its bottom a flow opening 32 that from the ball 29 under the action of the compression spring 30 is closed. Preloaded held the compression spring 30 of the penholder 31 , which is made according to the invention of a bent wire whose structure in the 4 is shown in detail as the first embodiment. The wire is held in three on the circumference of the housing 28 distributed openings 43 ,

While in 2a the check valve is shown in its closed position, it is in 2 B shown in its open position. The view here is 90 ° opposite the view in 2a turned. Here is the ball 29 against the force of the compression spring 30 lifted and thus gives the flow opening 32 free. Furthermore, it is visible here that the pen 31 due to its shape at the same time as a stop for the opening stroke of the ball 29 serves. This prevents the compression spring 30 can go to block stop.

3 shows a perspective view of the check valve 27 from above. Here is visible how a part of the penholder 31 in the of the compression spring 30 enclosed interior protrudes. As a result, the compression spring is guided on a partial circumference and part length, so that bulging or buckling when opening the check valve is prevented.

So that the spring holder can fulfill these three functions (spring holder, opening stroke limitation and guidance of the compression spring), it is bent several times by 90 ° in different planes, like the 4a and 4b demonstrate.

Starting from a wire beginning 33 the wire is angled in the same plane by about 120 ° (wire section 34 ) and then again by about 10 °. Then it is then bent twice by 90 ° (wire section 35 . 36 and 37 ), so that the wire section 37 again parallel with a small distance to the wire section 35 runs. The wire section 36 lies on a circular path, on which also the free end of the wire beginning 33 lies. The sections 35 . 36 and 37 form the first middle area 31a of the spring holder 31

Next, the wire then becomes a wire section 38 bent 90 ° downwards, then twice in a plane 90 ° (wire sections 39 and 40 ) to be bent. The wire sections 39 and 40 serve the ball 29 as a stop at the opening stroke ( 2 B ). They form the second middle area 31b of the wire.

Then the wire is bent upwards again by 90 ° (wire section 41 ), and then finally bent 90 ° outwards (wire end 42 ). The two wire sections 38 and 41 run parallel again with a small distance to each other and form the third center area 31c of the wire. He prevent bulging of the compression spring 30 , Also this wire end 42 ends on the circular path, on which also the beginning of the wire 33 and the wire section 36 lie. These three sections are used to attach the spring holder to the housing 28 over the openings 43 , At the same time, the compression spring can 30 at the sections 34 . 35 . 37 and 42 support.

In the 5a to 7b becomes a second variant of the spring holder 31 used. Here are the same components with the same reference numerals as in the 2a to 4b designated. Also, the embodiments (with the exception of the spring holder 31 ) and functions of the individual components, so that a repetition of their functional description is superfluous.

As the 5a . 5b and 6 show are the wire sections 38 . 41 and 39 twice available. This is on the one hand an improved leadership of the compression spring 30 achieved, a buckling or buckling is reliably prevented, and on the other hand there are two stops for the ball to limit the opening stroke.

This is achieved by starting from the beginning of the wire 33 , in 7a and 7b The wire is now not bent by about 120 ° in a plane, but by 90 ° down (wire section 34 ' ), and then bent 90 ° again (wire section 34 '' ). Then it is bent further by 90 ° upwards (wire section 34 ''' ) so that it is parallel and with a small distance to the wire section 34 ' back up. Only then close the remaining wire sections from the 4a , b to, but with the exception that on the wire section 40 is omitted for reasons of space. This waiver affects the function of the stop for the opening stroke of the ball 29 not, because the wire section 34 '' in the same plane as the wire section 39 lies. The wire sections 34 '' and 39 form the second middle area 31b , By twice providing the third middle area 31c (made of wire section 34 ' and 34 ''' and wire section 38 and 41 ) is also the compression spring 30 guided on a plurality of inner peripheral portions on a portion of its length, so that bulging or buckling is reliably prevented.

The pre-assembled check valve 27 gets into the oil supply lines 21 and 22 pressed liquid-tight. For this purpose, an area of the housing 28 be widened on its outer circumference, as in the 2a , Federation 5a , b shown.

Alternative to the openings 43 can also be provided on the free edge of the housing recesses, which then receive the wire beginning, the first center region and the wire end. So that the spring stop 31 not in operation of the Pleuels is moved, have the oil supply lines 21 and 22 a stop that limits the depth of depression of the check valve and at the same time the recesses in the housing 28 closes.

In the case of openings 43 is the penholder 31 preferably made of spring steel. Then the wire beginning, the first middle portion and the wire end can be easily pressed together for mounting in the corresponding openings, so as to allow them to snap into the openings.

LIST OF REFERENCE NUMBERS

1

 pleuel

2

 Pleueloberteil

3

 Pleuelunterteil

4

 Pleuellagerauge

5

 connecting rod

6

 eccentric

7

 adjustment

8th

 piston pin

9

 working piston

10

 flap

11

 flap

12

 piston rod

13

 piston rod

14

 actuating piston

15

 actuating piston

16

 supporting cylinders

17

 supporting cylinders

18

 pressure chamber

19

 pressure chamber

20

 connecting rod bearing

21

 Oil supply line

22

 Oil supply line

23

 Oil return line

24

 Oil return line

25

 location hole

26

 control line

27

 check valve

28

Housing of 27

29

 Bullet

30

 compression spring

31

 penholder

31a

 first middle part

31b

 second middle part

31c

 third middle part

32

Flow opening in 28

33

 wire end

34-41

 wire section

42

 wire end

43

Openings in 28

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 102012112434 A1 [0007]

Claims (10)

Check valve ( 27 ) for a control system of a device for varying the compression ratio of a cylinder unit of a reciprocating internal combustion engine, comprising one in a housing ( 28 ) mounted ball ( 29 ), by a compression spring ( 30 ) is held in the closed position, characterized in that the compression spring ( 30 ) of one in the housing ( 28 ) arranged spring holder ( 31 ) is held. Check valve ( 27 ) according to claim 1, characterized in that the spring holder ( 31 ) is formed as a multiply bent wire, wherein a portion of the wire at the same time as a stop for the opening stroke of the ball ( 29 ) serves. Check valve ( 27 ) according to claim 2, characterized in that the wire is bent in such a way that its two end regions ( 33 . 42 ) and a first middle area ( 31a ) lie in a plane and radially outwardly to a wall of the housing ( 28 ) are bent. Check valve ( 27 ) according to claim 2 or 3, characterized in that the wire consists of spring wire and arranged in the wall of the housing openings ( 43 ) with at least two end regions ( 33 . 42 ) is held. Check valve ( 27 ) according to at least one of the preceding claims, characterized in that the first central region ( 31a ) also in one in the wall of the housing ( 28 ) arranged opening ( 43 ) is held. Check valve ( 27 ) according to at least one of the preceding claims, characterized in that at least the two end regions ( 33 . 43 ) of the wire over in the wall of the housing ( 28 ) arranged recesses are held Check valve ( 27 ) according to claim 2 or 3, characterized in that a second central region ( 31b ) of the wire within the compression spring ( 30 ) and is in a plane parallel to the first plane. Check valve ( 27 ) according to at least one of the preceding claims, characterized in that a third middle region ( 31c ) of the wire is perpendicular to the two planes. Check valve ( 27 ) according to at least one of the preceding claims, characterized in that the third central region of the wire is parallel to the longitudinal axis of the compression spring ( 30 ) and within the compression spring ( 30 ) runs. Control system for actuating two with an adjusting element ( 7 ) cooperating actuating piston ( 14 and 15 ) for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element ( 7 ) is adjustable by the engine forces of the reciprocating internal combustion engine in two different positions, in which the in support cylinders ( 16 and 17 ) guided single-acting actuator piston ( 14 and 15 ), which together with the support cylinders ( 16 and 17 ) each have a pressure chamber ( 18 . 19 ), in a retracted or extended position, the pressure chambers ( 18 . 19 ) each via an oil feed line ( 21 . 22 ), in which a check valve ( 27 ), with an oil supply ( 51 ), of which two pressure chambers ( 18 and 19 ) outgoing oil return lines ( 23 and 24 ) are connected to a switching valve, via which the oil return lines ( 23 and 24 ) are optionally pressure relieved, characterized in that the check valve is designed according to one or more of claims 1 to 9.

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