EP1913241B1 - Pneumatic pressure control valve - Google Patents

Abstract

The invention relates to a pneumatic pressure control valve (1) for controlling the pressure in the crankcase of an internal combustion engine. To this end, a regulating diaphragm (2) is provided inside the pressure control valve (1) whereby enlarging or reducing the size of the passage through a first larger outflow opening (15) and through at least one second smaller outflow opening (16) of the pressure control valve (1) that is separate and located at a distance from the first opening. The novel pressure control valve (1) is characterized in that: the regulating diaphragm (2) is acted upon by a single control spring (3); the spring force can be introduced by the single control spring (3) both into a diaphragm area (25), which interacts with the larger outflow opening (15), as well as into a diaphragm area (26) interacting with the at least one outflow opening (16); diaphragm area (25), which interacts with the larger outflow opening (15), can be displaced relative to the remaining regulating diaphragm (2) perpendicular to the diaphragm plane and which has an area equal to no greater than 1/5 of the total area of the regulating diaphragm (2); the regulating diaphragm (2) has an inner roll fold (21) around the diaphragm area (25) interacting with the larger outflow opening (15), and; the diaphragm area (26) of the regulating diaphragm (29) interacting with the at least one smaller outflow opening (16) is located outside of the inner roll fold (21).

Description

The present invention relates to a pneumatic pressure control valve for automatic control of the pressure in the crankcase of an internal combustion engine, wherein the pressure control valve is arranged in the course of a crankcase ventilation line, the passage of which by means of the pressure control valve in dependence on the differential pressure between a reference pressure and an applied pressure at an inlet of the pressure control valve automatically variable is, is provided in the pressure control valve, a clamped in a valve housing actuating diaphragm which is acted upon on the one hand by the reference pressure and on the other hand by the gas pressure and spring force, whereby when changing the differential pressure between the adjoining the control diaphragm areas the control diaphragm is adjusted and the control diaphragm the Passage through a first, larger outflow opening and through at least one separate, spaced apart second, smaller, parallel flow-through outflow opening the pressure control valve increased or decreased, wherein at decreasing pressure at the inlet of the pressure control valve by the control diaphragm first the larger outflow opening and only then the smaller outflow opening is closed.

With regard to the crankcase ventilation of modern internal combustion engines, the statutory and resulting As a result, the technical requirement that in the crankcase, regardless of the pressure in the intake tract of the internal combustion engine and regardless of the volume or mass flow of the crankcase ventilation gas in all operating conditions or map ranges of the internal combustion engine, taking into account a pressure drop in a usually provided Ölnebelabscheider a negative pressure in a predetermined pressure range, in practice z. B. between 0 and about 30 hPa. In order to keep the pressure in the crankcase with varying pressures in the intake and different flow rates of the crankcase ventilation gas as constant as possible, pressure control valves are predominantly used in both gasoline and diesel engines in which a function of a force acting on a control diaphragm pressure difference, a flow area of the Valve regulated and thus the crankcase pressure is maintained at a more or less constant value. A high control quality and thus a high degree of independence of the crankcase pressure from the pressure in the intake tract and the flow rate of the crankcase ventilation gas results in pressure control valves with a large area ratio between the control diaphragm surface and regulated by the control diaphragm Abströmquerschnitt from the pressure control valve. However, with regard to the total pressure loss across the pressure regulating valve, the outflow cross-section must not be too small. At the same time, the increasingly limited space requirements and the cost pressure force the development of pressure control valves with small construction dimensions, whereby the possible area of the control diaphragm is limited.

From the DE 101 55 176 A1 a pressure control valve of the type mentioned is known. In this known pressure control valve, the first outflow opening is a first Regelfeder and the second outflow opening assigned its own, second control spring. Each control spring exerts on itself on the control diaphragm in each case an opening force acting force. The first control spring should act only on a first membrane area and the second control spring act only on a second, different membrane area. A disadvantage is to be considered in this known pressure control valve, that it requires a relatively large number of items, in particular two different control springs due to the use of two separate control springs. This leads to an increased, manufacturing and assembly costs. In addition, it is unfavorable that when using multiple control springs whose tolerances add in the worst case so that a relatively large dispersion in the control characteristic, which has the pressure control valve in total, results. Finally, disturbing effects of the springs on the respective non-associated membrane area arise when the springs and the respectively associated membrane areas are not sufficiently far apart from each other; However, a large distance is difficult or impossible to keep in practice because of the usual space limitations.

Another pressure control valve is off DE 102 49 720 A1 known. This pressure regulating valve is specially designed for an internal combustion engine with a turbocharger. In an internal combustion engine having a turbocharger, crankcase ventilation must be connected both to the intake manifold upstream of the turbocharger via a first vent line section and to the intake manifold downstream of the turbocharger via a second vent line section. The pressure regulating valve described here has a valve seat cooperating with a valve body, which has a first output channel and a second output channel, wherein in each case one output channel is connected to one of the two aforementioned areas of the intake upstream or downstream of the turbocharger. Within the pressure control valve, the second output port is concentrically disposed about the first output port. In addition, a separate non-return valve is arranged in each output channel. When the turbocharger is in operation, venting takes place in the intake tract upstream of the turbocharger; If the turbocharger is not in operation, the venting takes place in the area of the intake tract downstream of the turbocharger. In this pressure control valve, therefore, depending on the turbocharger operating state, either only the first output channel or alternatively only the second output channel flows through the crankcase ventilation gas. Thus, while this known pressure control valve provides an automatic choice of the area of the intake tract into which the crankcase ventilation gases are introduced, this pressure control valve does not provide an improved control characteristic in view of the requirements set forth above, which are generally made to pressure control valves of modern internal combustion engines.

From the EP 0 471 142 B1 is another pressure control valve for installation in a vent line to an internal combustion engine, in particular between the crankcase and intake, known. This pressure regulating valve has a valve housing, which is composed of a cup-shaped housing lower part and a housing cover. The housing has an opening into the lower housing inlet and a branch opening from the lower outlet spout, whose centrally disposed within the valve housing end portion is formed as a valve seat. Furthermore, the valve has a sealed at its edge in a groove between the housing cover and the lower housing part clamped control diaphragm, which Valve housing divided into a valve chamber and connected via a ventilation duct with the atmosphere ventilation chamber. In this case, the membrane has a valve seat facing the valve end at the end of the valve. Furthermore, a compression spring is provided, which is supported on the bottom of the housing base and exerts a force on the membrane in the direction of the housing cover. Furthermore, it is essential in this pressure control valve, that between the valve plate of the diaphragm and the first valve seat on the lower housing part, an intermediate valve is arranged, which has a second valve seat, which faces the membrane and cooperates with the valve plate of the membrane. In addition, the intermediate valve has a valve plate which faces the valve seat of the housing base and cooperates therewith, wherein the intermediate valve is arranged on the membrane such that an axial relative movement between the diaphragm and the intermediate valve is possible. Preferably, a hollow cylindrical part is arranged on the membrane, which is provided on its jacket with openings and in which the intermediate valve is arranged. In addition, a further compression spring is preferably arranged between the diaphragm and the intermediate valve, which in the idle state holds open the second valve formed by the intermediate valve and the valve plate of the diaphragm.

Although the desired good control characteristic of the pressure control valve by means of the use of the two valves, namely the main valve and the intermediate valve is achieved with this known pressure control valve, but this advantage is associated with a very high cost of items and a correspondingly high installation costs. Since here too two compression springs are preferably used as control springs, the problem of an unfavorable superposition of spring tolerances also occurs here, plus further component tolerances due to the many individual parts.

For the present invention, therefore, the object is to provide a pressure control valve of the type mentioned above, which avoids the disadvantages set out and achieved in the case of a simple construction with few items and low assembly costs and low tolerances high control quality and reliable operation become.

The solution of this object is achieved according to the invention with a pressure control valve of the type mentioned, which is characterized in that the control diaphragm is acted upon by a single control spring to generate the spring force, that by the single control spring, the spring force in both a cooperating with the larger outflow membrane area can also be introduced into a membrane region cooperating with the at least one smaller outflow opening, that the membrane region which interacts with the larger outflow opening is adjustable relative to the rest of the control membrane perpendicular to the membrane plane and has an area which is at most 1/5 of the total area of the control membrane, in that the adjusting membrane has an inner rolled fold around the membrane area cooperating with the larger outflow opening and that the membrane area of the adjusting membrane cooperating with the at least one smaller outflow opening is located outside the d he inner roll fold lies.

The pressure control valve according to the invention has the advantage of a favorable control characteristic, because the crankcase pressure at high flow rates of the crankcase ventilation gas and low pressure applied to the pressure control valve pressure differences through the large outflow opening is regulated. If there is a drop in the pressure in the crankcase, the control diaphragm initially closes against the spring force of the control spring of the pressure control valve by axially approaching the larger outlet opening. If there is then a further drop in the crankcase pressure, the control diaphragm is adjusted with further deformation of the same single control spring and deformation of the control membrane in itself so that now also narrowed the at least one smaller outlet opening in its cross section and is closed in the limit. Since the remaining cross-section of the smaller outflow opening used for the closed-loop larger discharge port is smaller than the cross-section of the larger outflow opening, a favorable area ratio between the control diaphragm surface and the surface of the outflow cross section of the smaller outflow opening is now achieved even with small surface dimensions of the control diaphragm ensures a desired good control characteristic and high control quality. This statement applies in particular against the background that a serious reduction in the effective area of the control diaphragm and thus the force of the control diaphragm after placing the membrane area cooperating with the larger outflow opening is prevented by the relative mobility between the membrane areas cooperating with the different outflow openings. As a result, the pressure regulating valve, despite its particularly simple structure largely independent of the negative pressure in the intake tract holds the crankcase pressure in a desired, prescribed pressure range. Thus, the pressure control valve according to the invention allows a compact design with a relatively small area of the control diaphragm. As for the pressure control valve according to the invention, the control diaphragm both deformable as a whole and defined in itself deformable, ie in their different, the various outflow openings assigned areas relative to each other must be adjustable, the control diaphragm around the cooperating with the larger outflow opening membrane area around an inner roll fold, wherein the cooperating with the at least one smaller discharge opening membrane region of the control diaphragm is located outside of the inner roll fold. This advantageously results in a low loss of effective membrane area after placement on the larger outflow opening, since the remaining membrane effective area is still large. The inner roll fold provided in the control membrane ensures that an inner region of the control membrane located inside the inner roll fold and an outer region of the control membrane lying outside the inner roll fold can be adjusted relative to one another in a defined and reproducible manner, wherein the various Membrane areas do not interfere with each other in an adjustment relative to each other. Instead of the roll fold can be provided to achieve the same function and equivalent means in the membrane, for example, areas of different hardness, which can be produced with two-component material, or material dilutions for targeted local increase in the flexibility of the membrane or a bellows. Furthermore, it is particularly advantageous that the pressure control valve according to the invention requires only a single control spring. The pressure control valve thus comes with a very small number of items, which ensures easy and cost-effective production and installation. In addition, it is thus avoided that tolerances of several components subject to tolerances, such as springs, unfavorably add up to an undesirably large total tolerance.

An even better control behavior can be achieved if the diaphragm area, with the larger outflow opening cooperates, has an area which is at most 1/8 of the total area of the control diaphragm. The effective area reduction of the control membrane after closing the larger outflow opening is kept even lower.

A preferred embodiment of the invention provides that seen in section parallel to the control diaphragm, the valve housing is round. This shape contributes to a compact design and avoids the need for a stretched or elongated valve housing which would generally be more difficult to accommodate in the area of an internal combustion engine.

A further development proposes that the larger outflow opening centrally in the valve housing and the smaller outflow opening is arranged eccentrically in the valve housing. This arrangement also contributes to a compact, space-saving design.

An alternative embodiment proposes that in addition to the larger outflow opening are provided symmetrically to and radially outside of this two or more smaller outflow openings. This symmetrical arrangement has advantages, in particular with regard to the design of the control diaphragm, since in this embodiment the control diaphragm itself can also be implemented symmetrically. This simplifies and reduces the production of the control diaphragm and avoids errors in the assembly of the pressure control valve. In addition, this results in symmetrical forces acting on the control diaphragm, which is advantageous for their adjustment and deformation and thus for the function of the valve.

Furthermore, it is preferably provided that with two or more smaller outflow openings, the cross-sectional area of the larger outflow opening is greater than the cross-sectional area sum of the two or more smaller outflow openings. In this way, it is reliably ensured that even with the execution of the valve with several smaller outflow openings already closed by the control diaphragm larger outflow advantageous for the high control quality favorable area ratio between the surface of the control diaphragm and the entire cross-sectional area of the two or more smaller outflow openings results.

A preferred embodiment is characterized in that the at least one smaller outflow opening is bounded by a cooperating with the control diaphragm sealing surface, seen in the closing direction of the adjusting diaphragm behind a likewise cooperating with the control diaphragm, the larger outflow opening bounding sealing surface. With this embodiment, it is achieved that, when the control diaphragm first moves in the closing direction as a whole, it initially only comes into abutment against the sealing surface, which surrounds the larger outflow opening; only by a further adjustment and deformation of the control diaphragm, even now against the force of the same control spring, the control diaphragm also reaches the sealing surface, which bounds the at least one smaller outflow opening. In this way, the desired two-stage control behavior is effected with little effort.

Specifically, the sealing surface of the at least one smaller outflow opening preferably lies behind it by 0.2 to 1.0 mm, preferably by 0.3 to 0.6 mm, behind the sealing surface of the larger outflow opening. As can be seen here, In practice, therefore, very small measures in the differentiation of the position of the two sealing surfaces are sufficient to reliably achieve the desired function. In this case, this stage can advantageously be generated relatively accurate tool falling.

In order to keep the control membrane as simple as possible and thereby cost-effective, the control diaphragm is preferably round over its surface and the inner rolled fold is preferably arranged concentrically to the central axis of the control diaphragm.

A further embodiment of the pressure control valve provides that the control spring on the control diaphragm initiates the spring force in an annular region which surrounds the membrane region cooperating with the larger outflow opening, while the membrane region interacting with the at least one smaller outflow opening lies outside this annular region. The introduction of the spring force in the control diaphragm thus takes place here in a membrane part which is located between the cooperating with the different outflow membrane areas. Thus, the spring force of the control spring reaches the various membrane areas on short, comparably long paths.

In an alternative embodiment, it is provided that the control spring introduces its spring force on the control diaphragm in an annular region which encloses both the membrane region cooperating with the larger outflow opening and the membrane region cooperating with the at least one smaller outflow opening. In this embodiment, the ways in which the spring force of the control spring reaches the membrane areas cooperating with the various outflow openings are different long; These different lengths of way can be used specifically to let the single control spring act to varying degrees on the different membrane areas.

The control spring of the pressure control valve according to the invention is preferably a helical spring. In this form, the control spring is a low-cost and reliable component that can be manufactured with low tolerances at low production costs. In addition, the coil spring offers the possibility to initiate the spring force, as described above, in an annular region in the control diaphragm, without additional measures, which is advantageous for a symmetrical loading of the control diaphragm.

Next, the invention proposes that the control diaphragm has at least one membrane support body which is arranged radially outwardly of the inner rolled fold in or on the control diaphragm. With the support body, the control diaphragm can be reinforced and stiffened in desired areas in order to specifically influence the properties and function of the control diaphragm and to achieve a long durability for the purpose of the longest possible trouble-free operation. At the same time the active surface of the control diaphragm is maximized by the support body, so that despite small dimensions of the pressure control valve, a good characteristic curve is achieved. The membrane support body can be arranged as a separate component between the control spring and the control diaphragm and thereby preferably linked to the control diaphragm or alternatively integrally connected by injection molding with the control diaphragm and integrated into it.

In order to make the control membrane as a whole easily adjustable and at the same time as easy to install in the housing of the pressure control valve, it is further preferred that the control diaphragm near its outer region has an outer rolled fold.und with an outer edge of the membrane clamped between two interconnected Parts of the valve housing is held. Since the control diaphragm usually consists of a Elastomär- or rubber material, the desired sealing is achieved without the use of special seals by clamping at the same time. In this embodiment, the membrane support body mentioned in the preceding paragraph is preferably arranged radially between the inner and the outer roll fold. Instead of the rolled fold, equivalent means may be provided in the membrane to achieve the same function, for example, as mentioned above in connection with the inner roll fold areas of different hardness, which can be generated with two-component material, or material dilutions for targeted local increase in flexibility the membrane or a bellows.

Next is provided for the pressure control valve, that the larger outflow opening and the at least one smaller outflow opening open into a common outlet of the pressure control valve. In this way, it is achieved that the pressure control valve can be connected to the internal combustion engine via only two lines, namely an inlet leading to the inlet and a line leading away from the outlet. Alternatively, it is also possible to connect the larger outflow opening on the one hand and the at least one smaller outflow opening on the other via a separate outlet and further separate lines with different locations of the internal combustion engine, in particular different sections of the intake tract, if this is advantageous or necessary for the function.

Alternatively, the larger outflow opening and the at least one smaller outflow opening may each open into a separate outlet of the pressure regulating valve. This embodiment may serve to apply the crankcase ventilation gas flowing out of the pressure control valve to two different portions of the intake tract of the associated internal combustion engine, e.g. in front of and behind a throttle or in front of and behind a turbocharger.

A development of the embodiment described above provides that in each outlet a check valve is arranged. This will produce an automatic, e.g. achieved by the pressure in each section of the intake tract dependent opening and closing of the two outlets.

Thus, the control diaphragm occupies a defined basic position in the absence of pressure difference within the pressure control valve, a stop is expediently provided in the valve housing and / or on the control diaphragm, which limits the path of movement of the control diaphragm in the opening direction. This ensures that the control diaphragm has a certain distance from the outflow openings in its basic position.

A further advantageous embodiment of the pressure control valve is that a stop is preferably provided within the control diaphragm, which prevents a leading movement of the cooperating with the larger outflow diaphragm portion of the control diaphragm in the closing direction relative to the cooperating with the at least one smaller outlet opening membrane region of the control diaphragm or limited. Hereby becomes prevents unwanted premature closing of the larger outflow opening by "sucking" the cooperating with the larger outflow membrane area. Rather, the diaphragm region of the control diaphragm which cooperates with the larger outflow opening can only move in the closing direction together with the diaphragm region of the control diaphragm cooperating with the at least one smaller outflow opening. Only the membrane region cooperating with the at least one smaller outflow opening is able to move further in the closing direction, independently of the other membrane region, when the other membrane region closes the larger outflow opening and thus reaches its end position.

With regard to the abovementioned stop, it is preferably provided that this stop is formed within the setting diaphragm by a stopper disc which engages with the membrane area cooperating with the at least one smaller outflow opening on the side facing away from the outflow openings and which is arranged on the other, with the larger outflow opening. The stop disc is a simple component that can be produced inexpensively and quickly and easily connected to the control diaphragm.

In the case of high demands on the characteristic curve of the pressure regulating valve, it may be advantageous to design the smaller outflow opening (s) as a Laval nozzle (s). If there are several smaller outlet openings, the Laval nozzles can have the same or different sizes. This ensures that at pressure differences between the inflow side of the outflow opening (s) and the intake above a certain threshold, for example about 180 hPa, in the narrowest gap, a critical pressure gradient adjusts so that the pressure drop is limited to eg about 180 hPa for the throttling at the gap between the control membrane and the / the smaller discharge opening (s) even at high pressures in the intake system. As a result, greater independence of the crankcase pressure from the negative pressure in the intake tract is achieved in the described map areas. The effect of this measure on the control characteristic of the pressure control valve is comparable in the mentioned operating conditions with an increase in the effective area ratio of the control diaphragm.

As is known per se, the pressure control valve according to the invention can optionally be designed as a single unit which can be connected to an internal combustion engine or, alternatively, be integrated into a component of the internal combustion engine, for example its valve cover.

The individual parts of the pressure control valve, except the control diaphragm and the control spring, are expedient injection molded plastic parts to allow cost-effective mass production with high accuracy.

Figur 1

ein erstes Druckregelventil im Vertikalschnitt in einem ersten Betriebszustand,

Figur 2

das Druckregelventil aus Figur 1 in gleicher Darstellung in einem zweiten Betriebszustand,

Figur 3

das Druckregelventil aus den Figuren 1 und 2 in gleicher Darstellung in einem dritten Betriebszustand,

Figur 4

eine Stellmembran des Druckregelventils gemäß den Figuren 1 bis 3 als Einzelteil in einem vergrößerten Vertikalschnitt,

Figur 5

das Druckregelventil aus Figur 1 im Horizontalschnitt gemäß der Schnittlinie V-V in Figur 1,

Figur 6

das Druckregelventil in einer zweiten Ausführung im Vertikalschnitt in einem Betriebszustand, der dem in Figur 1 gezeigten Betriebszustand entspricht,

Figur 7

das Druckregelventil in einer geänderten Ausführung in einem Teil-Vertikalschnitt, und

Figur 8

das Druckregelventil in einer weiteren Ausführung im Vertikalschnittschnitt in einem Betriebszustand, der dem in Figur 1 gezeigten Betriebszustand entspricht.

In the following embodiments of the pressure control valve according to the invention will be explained with reference to a drawing. The figures of the drawing show:

FIG. 1

a first pressure control valve in vertical section in a first operating state,

FIG. 2

the pressure control valve off FIG. 1 in the same representation in a second operating state,

FIG. 3

the pressure control valve from the FIGS. 1 and 2 in the same representation in a third operating state,

FIG. 4

a control diaphragm of the pressure control valve according to the FIGS. 1 to 3 as a single part in an enlarged vertical section,

FIG. 5

the pressure control valve off FIG. 1 in horizontal section along the section line VV in FIG. 1 .

FIG. 6

the pressure control valve in a second embodiment in vertical section in an operating condition corresponding to the in FIG. 1 corresponds to the operating state shown,

FIG. 7

the pressure control valve in a modified version in a partial vertical section, and

FIG. 8

the pressure control valve in a further embodiment in vertical section section in an operating condition corresponding to the in FIG. 1 corresponds to the operating state shown.

As the FIGS. 1 to 3 show, the pressure control valve 1 shown here has a housing 10 which is closed on the top side with a lid 10 '. From the left, an inlet 11 opens into the housing 10. To the right goes from the housing 10, an outlet 12. Both the inlet 11 and the outlet 12 are each formed here as a pipe socket for connecting in each case a continuing, not shown here line. The inlet 11 is usually connected to the crankcase of an associated internal combustion engine; the outlet 12 is usually connected to the intake tract of an internal combustion engine, not shown here.

In the housing 10 is between the top and the lid 10 'a control diaphragm 2 with its membrane edge 20 sealingly clamped and held. The control diaphragm 2 separates an area 13 below it in the housing 10 from an upper area 14 lying between the control diaphragm 2 and the cover 10 '. The area 14 communicates with a reference pressure source via a reference pressure port 14', which in the simplest case the surrounding atmosphere can be.

Centrally below the control diaphragm 2, a first, larger discharge opening 15 is arranged, which has the shape of a pipe section, the upper end face of which forms an annular sealing surface 15 '. At the lower end of the pipe section, the discharge opening 15 is connected to the outlet 12.

To the left and right of the larger outflow opening 15 is spaced from each have a smaller discharge opening 16, also in the form of a respective pipe section arranged. The upper front end of the two smaller outflow openings 16 each forms an annular sealing surface 16 '. At the lower end, the two smaller outflow openings 16 forming pipe sections are also connected to the outlet 12.

Concentric with the larger outflow opening 15 and radially outside the two smaller outflow openings 16 designed as a helical spring control spring 3 in the region 13 of the housing 10 is arranged. The control spring 3 is supported with its lower end on the housing 10 and exerts with its upper end in an annular region 29 an acting in the opening direction spring force on the control diaphragm 2. To secure the position of the control spring 3 relative to the control diaphragm 2 has the latter one integrated membrane support body 24, of which integrally projecting a Federzentrierring 28 downwards, which surrounds the upper end of the control spring 3.

The control membrane 2 is seen here in plan view circular and has two concentric rolling folds 21 and 22. The roll fold 21 is arranged as an inner roll fold in a region of the control diaphragm 2, which cooperates between a membrane region 25 which cooperates with the larger outflow opening 15 and a membrane region 26, which cooperates with the two smaller outflow openings 16, is arranged. The second roll fold 22 is arranged as an outer rolled fold directly radially inward from the clamping edge 20 of the control membrane 2.

At its side remote from the outflow openings 15, 16 side, the control diaphragm 2 has a central, undercut projection 23 ', on which a stop plate 23 is latched. The stop disc 23 extends in the radial direction outwardly beyond the inner roll fold 21 away into a region above the membrane portion 26, which cooperates with the smaller outflow openings 16.

By stops 27, which are arranged at the top of the control diaphragm 2 in the radially outer portion immediately radially inward of the outer roll fold 22, a defined, in FIG. 1 shown position of the control diaphragm 2 causes in its open position. In this position, the stops 27 on the underside of the lid 10 'are formed on it, downwardly facing projections.

The in FIG. 1 illustrated operating state in which the control diaphragm 2 is in its upper end position, assumes the pressure control valve 1, if no pressure difference is present, ie in particular at standstill of the associated internal combustion engine. In this state, the control spring 3 ensures that the control diaphragm is moved up to the start of the attacks 27 against the lid 10 'upwards or held in this position.

FIG. 2 shows a second operating state of the pressure regulating valve 1, which occurs when the pressure in the crankcase of the internal combustion engine drops. This sinking pressure propagates through the inlet 11 into the region 13 below the control diaphragm 2 of the pressure control valve 1 and causes a force acting on the control diaphragm 2 pressure difference and thus an adjusting force. The pressure difference moves against the force of the control spring 3, the control diaphragm 2 in total in the closing direction until, as in FIG. 2 shown, the central diaphragm portion 25 comes into contact with the sealing seat 15 'of the larger discharge opening 15.

In addition to the sealing seat 15 'are the sealing seats 16' of the two smaller outflow openings 16 seen in the closing direction of the control diaphragm 2 behind the sealing seat 15 'back, so that in the in FIG. 2 illustrated state, the membrane portions 26, which cooperate with the two smaller outflow openings 16, still have a distance from the associated sealing seats 16 'of the smaller outflow openings 16. In this state, the crankcase ventilation gas to be discharged from the crankcase flows only through the two smaller outflow openings 16, which have a free cross section, which in total is significantly smaller than the cross section of the larger outflow opening 15; This results in a favorable ratio of the surface of the control diaphragm 2 to the cross-sectional area of the two smaller outflow openings 16 with high control quality. Because of the Flexibility of the cooperating with the outflow opening 15 membrane region 25 arranged inner fold 21 decreases when placing the control diaphragm 2 on the sealing seat 15 ', the membrane effective area and thus the remaining membrane force only slightly. Here, therefore, the pressure control in the crankcase is effected only by the two smaller outflow openings 16 and the membrane region 26 cooperating therewith.

FIG. 3 shows the pressure control valve 1 from the FIGS. 1 and 2 now in a third operating state, in, after the larger outflow opening 15 now the two smaller outflow openings 16 are closed. This condition occurs when the pressure in the crankcase of the internal combustion engine drops so far that the pressure difference caused thereby now also the so far downwardly cooperating with the smaller outlet openings membrane region 26 of the control diaphragm 2 against the force of the same control spring 3, until the membrane region 26 comes into sealing contact with the sealing seats 16 'of the two smaller outflow openings 16. In this state, no crankcase ventilation gas can flow through the pressure control valve 1, whereby the pressure in the crankcase increases again until the pressure difference thereby changed again to an adjustment first of the outer membrane part 26 and, with further increasing pressure, and the inner membrane part 25 in the opening direction, up here, leads.

FIG. 4 shows an enlarged view of the control diaphragm 2 in cross section as a single part. Completely outside, ie in FIG. 4 left and right, the radially outer edge of the membrane 20 is visible, which serves for sealing clamping of the control diaphragm 2 between the housing and its lid. Radially inward on the edge 20 follows the outer Roll fold 22, which serves to adjust the control diaphragm 2 in total.

Radially further inward, the membrane support body 24, which is embedded in the remaining membrane 2 follows. The control diaphragm 2 has upwardly projecting ribs, which form the stop 27 for the movement of the control diaphragm 2 in the opening direction, ie upwards. Projecting downwardly, the membrane support body 24 has the one-piece spring centering ring 28.

Radially further inward, the inner rolled fold 21 then follows, separating the central membrane region 25 from the membrane region 26 which projects radially outwards onto the roll fold 21.

On the upper side, the control membrane 2 has the central, undercut projection 23 ', on which the stop plate 23 is latched. The stop disc 23 protrudes in the radial direction outwardly beyond the inner roll fold 21 away over the membrane area 26. Wie die FIG. 4 illustrated, the bottom of the stop plate 23 forms in its radially outer region a stop 27 'for the top 26' of the diaphragm portion 26. This ensures that the central diaphragm portion 25 relative to the radially outwardly therefrom membrane portion 26 is not leading in the axial direction leading can adjust. Rather, the central membrane region 26 can only be moved downwards in this direction together with the membrane region 26 located radially outside the inner roll fold. Conversely, however, there is the freedom that the lying radially outward of the inner roll fold 21 membrane portion 26 moves relative to the radially inner membrane portion 25 in the axial direction downwards, as already in connection with the FIG. 3 has been described.

Radially inside of Federzentrierring 28 is an annular portion 29 of the control diaphragm 2, in which the control spring not shown here rests with its upper end and exerts its upward spring force on the control diaphragm 2.

FIG. 5 shows the pressure control valve according to the FIGS. 1 to 3 in a longitudinal section along the section line VV in FIG. 1 , Particularly clearly shows the FIG. 5 in that the housing 10 is round and that, accordingly, the control membrane, which is not visible here, has a suitable round outline.

Left in FIG. 5 the inlet 11 for the crankcase ventilation gas can be seen; to the right, the outlet 12 goes off.

In the center of the housing 10 is in the housing portion 13, ie below the not visible here Stellmembran, the larger outflow opening 15 with her here the viewer facing sealing surface 15 '.

Left and right of the central larger outflow opening 15, the two smaller outflow openings 16 are arranged eccentrically and at a distance, in which case each of their sealing surface 16 'faces the viewer.

FIG. 6 shows a modified version of the pressure control valve 1, which differs from the previously described embodiment essentially in that the example according to FIG. 6 dispensed with a stop disk in the control diaphragm 2. The central part of the control diaphragm 2 here forms the diaphragm region 25, which cooperates with the central, larger outflow opening 15. Radial outwardly from this follows the inner rolled fold 21, which in turn continues radially outwardly adjoining the membrane region 26, which cooperates with the two smaller outflow openings 16. Radially outermost here is the control diaphragm 2 by means of their membrane edge 20 sealingly held between the housing 10 and the lid 10 '. Inside the housing 10, the radially outer roll fold 22 lies directly radially inward from the clamping edge 20. Between the radially outer roll fold 22 and the radially inner roll fold 21, the membrane support body 24 is arranged in the control membrane 2, which stiffens this part of the membrane 2. Again, the control diaphragm 2 carries upwardly projecting ribs, which form the stop 27 for limiting the movement of the control diaphragm 2 in the opening direction. On the underside, here too the membrane support body 24 has the spring centering ring 28. Radially inwardly of this Federzentrierring 28 which also here the shape of a coil spring having control spring 3 is located at its upper end to the annular portion 29 of the control diaphragm 2 and exerts its spring force in the opening direction, ie upwards, on the control diaphragm 2.

The in FIG. 6 shown operating state of the pressure control valve 1 adjusts when there is no pressure difference across the control diaphragm 2. In this state, the control spring 3 pushes the control membrane 2 in the opening direction upwards until it rests with its stop 27 on the underside of the lid 10 '.

With decreasing pressure in the crankcase of the associated internal combustion engine, ie with decreasing pressure in the inlet 11 and in the housing portion 13, the control diaphragm 2 moves downwards due to the pressure difference applied thereto, whereby also here, as in FIG. 2 already described, First, the central membrane area 25, the larger outlet opening 15 is reduced and finally closes. As the pressure in the crankcase continues to fall, the diaphragm region 26 lying radially outward moves even further down until it initially reduces the size of the two smaller outflow openings 16 and finally completely closes them. The functions of the pressure control valve 1 according to FIG. 6 So correspond to the functions of the pressure control valve, which in the FIGS. 1 to 3 was shown and explained. Also the others in FIG. 6 visible items correspond to the items according to the previously described drawing figures with the same reference numerals.

FIG. 7 shows in a partial vertical section a section of a pressure control valve 1 in a further embodiment. Characteristic of this embodiment is that the two smaller outflow openings 16 are each here in the form of a Laval nozzle. The cross section of the two smaller outflow openings 16 is initially seen relatively small in the flow direction, and then becomes slower again after a smallest diameter. The execution of the smaller outflow openings 16 as Laval nozzles offers the advantage that at pressure differences between the inflow side of the outflow openings 16, here in the region 13 of the valve housing 10, and the outlet 12, which is usually connected to the intake of an associated internal combustion engine, above a certain Limit value, in practice, for example, about 180 hPa, at the narrowest point of the discharge openings 16 sets a so-called critical pressure gradient. Thus, for the throttling at the gap between the control membrane and the smaller outflow openings 16, the pressure drop to the aforementioned limit even with a strong negative pressure in the outlet 12, For example, limited to 180 hPa. In this way, a greater independence of the crankcase pressure from the negative pressure in the outlet 12 is achieved.

FIG. 8 shows in the same representation as the FIG. 1 a further embodiment of the pressure control valve 1. In most parts, the pressure control valve 1 is true with the pressure control valve 1 according to the FIGS. 1 to 3 match.

Unlike the examples described above, in the pressure control valve 1 according to FIG. 8 in that the larger outflow opening 15 opens into a first outlet 12 and that the two smaller outflow openings 16 open together into a second outlet 12 ', which is fluidly separated from the first outlet 12. Thereby, it is possible to supply the partial flow of the crankcase ventilation gas, which flows through the outlet 12, to another region of the intake tract of an associated internal combustion engine than the partial flow of the crankcase ventilation gas, which flows through the other outlet 12 '.

In addition, each outlet 12, 12 'is assigned its own non-return valve 17, 17'. The check valves 17, 17 'adjust automatically depending on the pressure conditions on the two sides of the check valve 17 and 17', so that depending on the existing pressure conditions automatic opening and closing of the outlet 12 and the outlet 12 'is effected.

Claims (21)

1. A pneumatic pressure regulating valve (1) for automatically regulating the pressure in the crankcase of an internal combustion engine, wherein the pressure regulating valve (1) is arranged in the path of a crankcase ventilation line, the opening of which can be automatically changed by means of said pressure regulating valve (1) in relation to the differential pressure between a reference pressure and a gas pressure applied to an inlet (11) of said pressure regulating valve (1), wherein a control diaphragm (2) inserted in a valve casing (10) is provided in the pressure regulating valve (1), said control diaphragm (2) being, on the one hand, subjected to the reference pressure and, on the other hand, to the gas pressure as well as the force of a spring, wherein a change in the differential pressure between the regions (13, 14) adjacent to the control diaphragm (2) causes an adjustment of the control diaphragm (2) and the control diaphragm (2) increases or reduces the passage through a first larger outflow opening (15) and through at least one smaller second outflow opening (16) of the pressure regulating valve (1), said second outflow opening (16) being separated and spaced apart from and being throughflowable in parallel to said first outflow opening (15), wherein, with the pressure at the inlet (11) of the pressure regulating valve (1) decreasing, the control diaphragm (2) can, at first, close the larger outflow opening (15) and only thereafter the smaller outflow opening (16),
   characterized in

   - that the control diaphragm (2) is loaded by a single governor spring (3) acting in the opening direction and provided for generation of the spring force,

   - that, by means of the single governor spring (3), the spring force can be introduced both into a diaphragm region (25) associated with the larger outflow opening (15) and into a diaphragm region (26) associated with the at least one smaller outflow opening (16),

   - that the diaphragm region (25) that is associated with the larger outflow opening (15) is adjustable perpendicularly to the plane of the diaphragm in relation to the remaining control diaphragm (2) and comprises a surface area which amounts to no more than one fifth of the total surface area of the control diaphragm (2),

   - that the control diaphragm (2) comprises an inner roll corrugation (21) around the diaphragm region (25) associated with the larger outflow opening (15), and

   - that the diaphragm region (26) of the control diaphragm (29) that is associated with the at least one smaller outflow opening (16) is positioned outside the inner roll corrugation (21).
2. The pressure regulating valve according to Claim 1, characterized in that the diaphragm region (25) that is associated with the larger outflow opening (15) comprises a surface area which amounts to no more than one eighth of the total surface area of the control diaphragm (2).
3. The pressure regulating valve according to Claim 1 or 2, characterized in that the valve casing is round in section, as seen in parallel to the control diaphragm (2).
4. The pressure regulating valve according to anyone of Claims 1 to 3, characterized in that the larger outflow opening (15) is arranged centrally in the valve casing (10) and the smaller outflow opening (16) is arranged eccentrically in the valve casing (10).
5. The pressure regulating valve according to anyone of Claims 1 to 3, characterized in that the larger outflow opening (15) is arranged centrally in the valve casing (10) and that, adjacent to the larger outflow opening (15), two or more smaller outflow openings (16) are provided symmetrically therewith and in a radially outward direction therefrom.
6. The pressure regulating valve according to Claim 5, characterized in that the cross-sectional area of the larger outflow opening (15) is in excess of the sum total of the cross-sectional areas of the two or more smaller outflow openings (16).
7. The pressure regulating valve according to anyone of the preceding claims, characterized in that the at least one smaller outflow opening (16) comprises a sealing surface (16') which is associated with the control diaphragm (2) and, as seen in the direction of the closing movement of the control diaphragm (2), is positioned downstream of a sealing surface (15') of the larger outflow opening (15), said sealing surface (15') also being associated with the control diaphragm (2).
8. The pressure regulating valve according to Claim 7, characterized in that the sealing surface (16') of the at least one smaller outflow opening (16) is positioned downstream of the sealing surface (15') of the larger outflow opening (15) by 0.2 to 1.0 mm, preferrably by 0.3 to 0.6 mm.
9. The pressure regulating valve according to anyone of the preceding claims, characterized in that the control diaphragm (2) is round as seen across its surface area and that the inner roll corrugation (21) is arranged concentrically in relation to the central axis of the control diaphragm (2).
10. The pressure regulating valve according to anyone of Claims 1 to 9, characterized in that the governor spring (3) exerts the spring force on the control diaphragm (2) in an annular region (29) which encloses the diaphragm region (25) associated with the larger outflow opening (15) whereas the diaphragm region (26) associated with the at least one smaller outflow opening (16) is positioned outside this annular region (29).
11. The pressure regulating valve according to anyone of Claims 1 to 9, characterized in that the governor spring (3) exerts the spring force on the control diaphragm (2) in an annular region (29) which encloses both the diaphragm region (25) associated with the larger outflow opening (15) and the diaphragm region (26) associated with the at least one smaller outflow opening (16).
12. The pressure regulating valve according to anyone of the preceding claims, characterized in that the governor spring (3) is a helical spring.
13. The pressure regulating valve according to anyone of the preceding claims, characterized in that the control diaphragm (2) comprises at least one diaphragm supporting body (24) which is arranged in or on the control diaphragm (2) in a radially outward direction in relation to the inner roll corrugation (21).
14. The pressure regulating valve according to anyone of the preceding claims, characterized in that the control diaphragm (2) comprises an outer roll corrugation (22) near its outer region and, with an outer diaphragm edge (20), is retained between two parts of the valve casing (10) in an inserted manner, said parts being connected to each other.
15. The pressure regulating valve according to anyone of Claims 1 to 14, characterized in that the larger outflow opening (15) and the at least one smaller outflow opening (16) end in a joint outlet (12) of the pressure regulating valve (1).
16. The pressure regulating valve according to anyone of Claims 1 to 14, characterized in that the larger outflow opening (15) and the at least one smaller outflow opening (16) each end in their own outlet (12, 12') of the pressure regulating valve (1).
17. The pressure regulating valve according to Claim 16, characterized in that a check valve (17, 17') is arranged in each outlet (12, 12').
18. The pressure regulating valve according to anyone of the preceding claims, characterized in that a stop (27) is provided in the valve casing (10) and/or on the control diaphragm (2), said stop (27) limiting the travel distance of the control diaphragm (2) in the opening direction.
19. The pressure regulating valve according to anyone of the preceding claims, characterized in that a stop (27') is provided in the interior region of the control diaphragm (2), said stop (27') preventing or limiting any leading movement of the diaphragm region (25) of the control diaphragm (2) that is associated with the larger outflow opening (15) in the closing direction thereof (25), in relation to the diaphragm region (26) of the control diaphragm (2) that is associated with the at least one smaller outflow opening (16).
20. The pressure regulating valve according to Claim 19, characterized in that the stop (27') in the interior region of the control diaphragm (2) is formed by a stop disk (23) that, on the side facing away from the outflow openings (15, 16), laps over the diaphragm region (26) associated with the at least one smaller outflow opening (16) and is arranged at the other diaphragm region (25) associated with the larger outflow opening (15).
21. The pressure regulating valve according to anyone of the preceding claims, characterized in that the smaller outflow opening(s) (16) is/are formed as de Laval nozzle(s).

Images